Polymer Layered Silicate Nanocomposites (Rapra review reports) (v. 14, No. 7)

RAPRA REVIEW REPORTS A Rapra Review Report comprises three sections, as follows: 1. A commissioned expert review, discussing a key topic of current interest, and referring to the References and Abstracts section. Reference numbers in brackets refer to item numbers from the References and Abstracts section. Where it has been necessary for completeness to cite sources outside the scope of the Rapra Abstracts database, these are listed at the end of the review, and cited in the text as a.1, a.2, etc. 2. A comprehensive References and Abstracts section, resulting from a search of the Rapra Polymer Library database. The format of the abstracts is outlined in the sample record below. 3. An index to the References and Abstracts section, derived from the indexing terms which are added to the abstracts records on the database to aid retrieval.

Source of original article Title

Item 1 Macromolecules

33, No.6, 21st March 2000, p.2171-83 EFFECT OF THERMAL HISTORY ON THE RHEOLOGICAL BEHAVIOR OF THERMOPLASTIC POLYURETHANES Pil Joong Yoon; Chang Dae Han Akron,University The effect of thermal history on the rheological behaviour of ester- and ether-based commercial thermoplastic PUs (Estane 5701, 5707 and 5714 from B.F.Goodrich) was investigated. It was found that the injection moulding temp. used for specimen preparation had a marked effect on the variations of dynamic storage and loss moduli of specimens with time observed during isothermal annealing. Analysis of FTIR spectra indicated that variations in hydrogen bonding with time during isothermal annealing very much resembled variations of dynamic storage modulus with time during isothermal annealing. Isochronal dynamic temp. sweep experiments indicated that the thermoplastic PUs exhibited a hysteresis effect in the heating and cooling processes. It was concluded that the microphase separation transition or order-disorder transition in thermoplastic PUs could not be determined from the isochronal dynamic temp. sweep experiment. The plots of log dynamic storage modulus versus log loss modulus varied with temp. over the entire range of temps. (110-190C) investigated. 57 refs.

Location

GOODRICH B.F. USA

Authors and affiliation

Abstract

Companies or organisations mentioned

Accession no.771897

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Polymer/Layered Silicate Nanocomposites

Masami Okamoto (Toyota Technological Institute)

ISBN 1-85957-391-6

Polymer/Layered Silicate Nanocomposites

Contents 1.

Introduction .............................................................................................................................................. 3

2.

Layered Silicates ...................................................................................................................................... 3

3.

4.

5.

2.1

Structure and Properties .................................................................................................................. 3

2.2

Organophilic Modification ............................................................................................................. 5

Preparative Methods for PLS Nanocomposites .................................................................................... 5 3.1

Intercalation of Polymer or Pre-Polymer from Solution ................................................................ 6

3.2

In Situ Intercalative Polymerisation Method .................................................................................. 6

3.3

Melt Intercalation Method .............................................................................................................. 6

Structure and Characterisation of PLS Nanocomposites .................................................................... 6 4.1

Structure of PLS Nanocomposites .................................................................................................. 6

4.2

Characterisation of PLS Nanocomposites ...................................................................................... 7

Types of Polymers for the Preparation of Nanocomposites ................................................................ 7 5.1

Vinyl Polymer Systems ................................................................................................................... 7 5.1.1 5.1.2 5.1.3 5.1.4

5.2

Condensation Polymers and Rubbers ............................................................................................11 5.2.1 5.2.2 5.2.3 5.2.4 5.2.5 5.2.6 5.2.7 5.2.8 5.2.9 5.2.10 5.2.11

5.3

PP/LS Nanocomposites .................................................................................................... 22 PE/LS Nanocomposites .................................................................................................... 24

Speciality Polymers ...................................................................................................................... 24 5.4.1 5.4.2

5.5

Nylon/LS Nanocomposites .............................................................................................. 12 PCL/LS Nanocomposites ................................................................................................. 14 PET/LS Nanocomposites ................................................................................................. 14 PBT/LS Nanocomposites ................................................................................................. 14 PC/LS Nanocomposites .................................................................................................... 15 PEO/LS Nanocomposites ................................................................................................. 15 LCP/LS Nanocomposites ................................................................................................. 16 PBO/LS Nanocomposites ................................................................................................. 16 EPR/LS Nanocomposites ................................................................................................. 16 PU/LS Nanocomposites ................................................................................................... 22 Polyimide/LS Nanocomposites ........................................................................................ 22

Polyolefins .................................................................................................................................... 22 5.3.1 5.3.2

5.4

PS/LS Nanocomposites ...................................................................................................... 9 PMMA/LS Nanocomposites .............................................................................................. 9 PVA/LS Nanocomposites ................................................................................................. 10 Block Copolymer/LS Nanocomposites ............................................................................ 10

PANI/LS Nanocomposites ................................................................................................ 25 PNVC/LS Nanocomposites .............................................................................................. 25

Biodegradable Polymers ............................................................................................................... 25 5.5.1 5.5.2

PLA/LS Nanocomposites ................................................................................................. 25 PBS/Clay Nanocomposites .............................................................................................. 28

1

Polymer/Layered Silicate Nanocomposites

6.

Properties of PLS Nanocomposite Materials ...................................................................................... 29 6.1

Dynamic Mechanical Analysis (DMA) ........................................................................................ 29

6.2

Tensile Properties .......................................................................................................................... 32

6.3

Flexural Properties and Heat Distortion Temperature .................................................................. 33

6.4

Thermal Stability .......................................................................................................................... 36

6.5

Fire Retardant Properties .............................................................................................................. 36

6.6

Gas Barrier Properties ................................................................................................................... 37

6.7

Ionic Conductivity ........................................................................................................................ 38

6.8

Optical Transparency .................................................................................................................... 39

6.9

Biodegradability............................................................................................................................ 39

6.10 Crystallisation ............................................................................................................................... 41 6.10.1 Spherulite Growth ............................................................................................................ 41 6.10.2 Effect of Intercalation on Enhancement of Dynamic Modulus ....................................... 41 6.10.3 Crystallisation Controlled by Silicate Surfaces ............................................................... 42 7.

8.

9.

Melt Rheology ........................................................................................................................................ 42 7.1

Linear Viscoelastic Properties ...................................................................................................... 42

7.2

Elongational Flow and Strain-Induced Hardening ....................................................................... 45

Processing Operations ........................................................................................................................... 47 8.1

Foam Processing Using Supercritical CO2 ................................................................................................................................................ 47

8.2

Shear Flow Processing .................................................................................................................. 47

8.3

Electrospinning ............................................................................................................................. 47

8.4

Porous Ceramic Materials ............................................................................................................. 48

Multifunctional Polyhedral Oligomeric Silsesquioxane Nanocomposites ....................................... 48

10. Carbon Nanotube Polymer Composites .............................................................................................. 49 11. Outlook ................................................................................................................................................... 49 Additional References ................................................................................................................................... 49 Abbreviations and Acronyms ....................................................................................................................... 51 Abstracts from the Polymer Library Database .......................................................................................... 53 Subject Index ............................................................................................................................................... 153 Company Index............................................................................................................................................ 163

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2

Polymer/Layered Silicate Nanocomposites

was thoroughly dispersed in advance (a.7, a.8). The resulting composite with a loading of only 4.2 wt% clay possessed a doubled modulus, a 50%-enhanced strength, and an increase in heat distortion temperature (HDT) of 80 °C compared to the neat Nylon 6, as shown in Table 1. Second, Vaia and co-workers (408) found that it is possible to melt-mix polymers with layered silicates without the use of organic solvents. Today, efforts are being conducted globally using almost all types of polymer matrices.

1 Introduction Polymer/layered silicate (PLS) nanocomposites have received a great deal of attention during the past decade. They often exhibit attractive improvement of material properties (393) when compared with pure polymer or conventional composites (both micro- and macro-composites). These improvements can include, high moduli (a.1), increased strength and heat resistance (a.2), decreased gas permeability (410) and flammability (a.3) and increased biodegradability of biodegradable polymers (a.4). On the other hand, these materials have also been proved unique model systems to study the structure and dynamics of polymers in confined environments (175, 176, 394).

This review is intended to highlight the major developments in this area during the last decade. The different techniques used to prepare PLS nanocomposites, their physicochemical characterisation, and the improved materials properties that those materials can display; the processing and probable applications of PLS nanocomposites will be reported in detail.

The main reason for these improved properties is interfacial interaction between the polymer matrix and organically modified layered silicate (OMLS) as opposed to conventional composites. Layered silicates (LSs) have layer thickness in the order of 1 nm and very high aspect ratios (e.g., 10-1000). A few weight percent of OMLS that is properly dispersed throughout the matrix thus creates a much higher surface area for polymer-filler interfacial interactions than in conventional composites (130).

2 Layered Silicates 2.1 Structure and Properties The commonly used layered silicates for the preparation of PLS nanocomposites belong to the same general family of 2:1 layered- or phyllosilicates. Their crystal structure consists of layers made up of two silica tetrahedral layers fused to an edge-shared octahedral sheet of either aluminium or magnesium hydroxide. The layer thickness is around 1 nm and the lateral dimensions of these layers may vary from 30 nm to several microns and even larger depending on the particular layered silicate. Stacking of the layers leads to a regular van der Waals gap between the layers called the interlayer or gallery. Isomorphic substitution within the layers (for example, Al+3 replaced by Mg+2 or by Fe+2, or Mg+2 replaced by Li+1) generates negative

Although the intercalation chemistry of polymers when mixed with appropriately modified layered silicate and synthetic layered silicates has been known for a long time (a.5, a.6), the field of PLS nanocomposites has gained large momentum recently. Two major findings stimulated the revival of these materials. First, Usuki, Fukushima and their colleagues of Toyota Central Research & Development Co. Inc. (TCRD) successfully prepared, for the first time, exfoliated Nylon 6/LS hybrid (NCH) via in situ polymerisation of ε-caprolactam, in which alkylammonium-modified montmorillonite (MMT)

Table 1 Mechanical and thermal properties of Nylon 6/clay hybrid (NCH) Properties

Nylon 6 Nanocomposite

Neat Nylon 6

Clay content (wt%)

4.2

0

Specific gravity

1.15

1.14

Tensile strength (MPa)

107

69

Tensile modulus (GPa)

2.1

1.1

Impact (kJ/m2)

2.8

2.3

HDT (°C at 1.8 MPa)

147

65

3

Polymer/Layered Silicate Nanocomposites

charges that are counterbalanced by alkali and alkaline earth cations situated inside the galleries. The type of layered silicate is characterised by a moderate surface charge (known as cation exchange capacity (CEC), and generally expressed by mequiv/100 g). This charge is not locally constant as it varies from layer to layer and must rather be considered as an average value over the whole crystal. MMT, hectorite, and saponite are the most commonly used layered silicates. LSs have two types of structure, i.e., tetrahedral-substituted and octahedral substituted. In the case of tetrahedral substituted layered silicates the negative charge is located on the surface of the silicate layers, and hence, the polymer matrices can react with tetrahedralsubstituted silicate more readily compared to

octahedral-substituted. Details regarding the structure and chemistry of these layered silicates are provided in Figure 1 and Table 2, respectively. There are two particular characteristics of layered silicates that we generally consider in PLS nanocomposites. The first is the ability of the silicate particles to disperse into the individual layers. The second characteristic is the ability to fine-tune their surface chemistry through ion exchange reactions with organic and inorganic cations. These two characteristics are, of course, interrelated since the degree of dispersion of layered silicate in a particular polymer matrix depends on the interlayer cation.

Figure 1 Structure of 2:1 phyllosilicates (Adapted from (a.9), S. Shinha Ray. et al., Macromolecules, 2003, 36, 2355, with permission from the American Chemical Society)

Table 2 Chemical formula and characteristic parameters of commonly used 2:1 phyllosilicates Chemical formulaa

CEC (mequiv/100 g)

Particle length (nm)

Montmorillonite

Mx(Al4-xMgx)Si8O20(OH)4

110

100-150

Hectorite

Mx(Mg6-xLix)Si8O20(OH)4

120

200-300

Saponite

MxMg6(Si8-xAlx)Si8O20(OH)4

86.6

50-60

2:1 Phyllosilicates

a

4

M = monovalent cation; x = degree of isomorphous substitution (between 0.3 and 1.3).

Polymer/Layered Silicate Nanocomposites

(a)

(b)

(c)

Figure 2 Alkyl chain aggregation models: (a) short chain lengths, the molecules are effectively isolated from each other, (b) medium lengths, quasi-discrete layers form with various degrees of inplane disorder and interdigitation between the layers and (c) long lengths, interlayer order increases leading to a liquid-crystalline polymer environment. Open circles represent the CH2 segments while cationic head groups are represented by filled circles. (Reprinted from (a.3), R. A. Vaia et al., Chem. Mater., 1994, 6, 1017, with permission from the American Chemical Society)

2.2 Organophilic Modification Any physical mixture of a polymer and layered silicate, however, does not form a nanocomposite. This situation is analogous to polymer blends, and in most cases separation into discrete phases normally takes place. In immiscible systems, which typically correspond to the more conventionally filled polymers, the poor physical interaction between the organic and the inorganic components leads to poor mechanical and thermal properties. In contrast, the strong interactions between the polymer and the layered silicate in PLS nanocomposites leads to the organic and inorganic phases being dispersed at the nanometer level. As a result nanocomposites exhibit unique properties not shared by their micro counterparts or conventionally filled polymers. Pristine layered silicates usually contain hydrated Na+ or K+ ions (a.10). Obviously, in this pristine state layered silicates are only compatible with hydrophilic polymers, such as polyethylene oxide (PEO) (139, 175, 195, 239, 384, 417), polyvinyl alcohol (PVA) (223, a.11) etc. To render layered silicates compatible with other polymer matrices, one must convert the normally hydrophilic silicate surface to organophilic, which makes the intercalation of many engineering polymers possible. Generally, this can be done by ion-exchange reactions with cationic surfactants including primary, secondary, tertiary, and quaternary alkyl ammonium or alkylphosphonium cations. The role of alkylammonium or alkylphosphonium cations in the organosilicates is to lower the surface energy of the inorganic host and to improve the wetting characteristics with the polymer matrix, and results in a larger interlayer spacing. One can evaluate that about 100 alkylammonium salt molecules are localised near the individual silicate layers (~8 × 10-15 m2) and active surface area (~800 m2/g).

Additionally, the alkylammonium or alkylphosphonium cations could provide functional groups that can react with the polymer matrix or in some cases initiate the polymerisation of monomers to improve the strength of the interface between the inorganic and the polymer matrix (386, a.12). Traditional structural characterisation to determine the orientation and arrangement of the alkyl chain involved primarily the use of wide angle X-ray diffraction (WAXD). Depending on the packing density, temperature and alkyl chain length, the chains were thought to lie either parallel to the silicate layers forming mono or bilayers, or radiate away from the silicate layers forming mono or bimolecular arrangements. Vaia and Giannelis (a.13) have shown that alkyl chains can vary from liquid-like to solid-like, with the liquid-like structure dominating as the interlayer density or chain length decreases (Figure 2), or as the temperature increases. They used Fourier transform infrared spectroscopy (FTIR), because of the relatively small energy differences between the trans and gauche conformers. The idealised models described earlier assume all trans conformations. In addition, for the longer chain length surfactants, the surfactants in the layered silicate can show thermal transition akin to melting or liquid-crystalline to liquid like transitions upon heating.

3 Preparative Methods for PLS Nanocomposites So far there have been many papers published devoted to developing PLS nanocomposites with different

5

Polymer/Layered Silicate Nanocomposites

combinations of OMLS, employing somewhat different technologies appropriate to each polymer and matrix polymers such as: •

epoxy resin (143, 193, 201, 255, 261, 277, 283, 313, 395),

•

polyurethane (PU) (118, 136, 171, 215, 225, 270, 272, 326, 356),

•

polyetherimide (PEI) (258, 289),

•

polybenzoxazine (212, 315),

•

polypropylene (PP) (149, 169, 180, 181, 187, 197, 198, 205, 208, 214, 227, 230, 262, 268, 271, 278, 319, 372, 374),

•

polystyrene (PS) (155, 160, 167, 204, 222, 235, 240, 248, 276, 300, 310, 323, 340),

•

polymethyl methacrylate (PMMA) (170, 240, 246, 280, 286, 323, 330, 389),

•

poly(ε-caprolactone) (PCL) (124, 141, 152, 154, 398) and

•

liquid crystalline polymers (LCP) (148, 285).

The technologies are broadly classified into three main categories.

3.1 Intercalation of Polymer or Pre-Polymer from Solution This is based on a solvent system in which polymer or pre-polymer is soluble and the silicate layers are swellable. The layered silicate is first swollen in a solvent, such as water, chloroform or toluene. When the polymer and layered silicate solutions are mixed, the polymer chains intercalate and displace the solvent within the interlayer of the silicate. Upon solvent removal, the intercalated structure remains, resulting in PLS nanocomposites.

3.3 Melt Intercalation Method This method involves annealing, statically or under shear, a mixture of the polymer and OMLS above the softening point of the polymer. This method has great advantages over either in situ intercalative polymerisation or polymer solution intercalation. Firstly, this method is environmentally benign due to the absence of organic solvents. Secondly, it is compatible with current industrial processes, such as extrusion and injection moulding. The melt intercalation method allows the use of polymers which were previously not suitable for in situ polymerisation or the solution intercalation method. This solvent-free method is much preferred for practical industrial material production because of its high efficiency and possibility of avoiding environmental hazards. Other possibilities are exfoliation-adsorption (a.14), and template synthesis (a.15).

4 Structure and Characterisation of PLS Nanocomposites 4.1 Structure of PLS Nanocomposites Layered silicates have layer thickness in the order of 1 nm and very high aspect ratio (e.g., 10-1000), thus creating a much higher surface area for polymer/filler interaction than in conventional composites. Depending on the strength of interfacial interaction between polymer matrix and layered silicate (modified or not), three different types of PLS nanocomposites are thermodynamically achievable (Figure 3) (a.9). (1) Intercalated nanocomposites: in an intercalated nanocomposite, the insertion of polymer matrix into the layered silicate structure occurs in a crystallographically regular fashion, regardless of the silicate layer (clay) to polymer ratio. Properties of the composites typically resemble those of ceramic materials.

3.2 In Situ Intercalative Polymerisation Method In this method, the OMLS is swollen within the liquid monomer or a monomer solution so that the polymer formation can occur in between the intercalated sheets. Polymerisation can be initiated either by heat or radiation, by the diffusion of a suitable initiator, or by an organic initiator or catalyst fixed through cation exchange inside the interlayer before the swelling step by the monomer.

6

(2) Flocculated nanocomposites: conceptually this is the same as with intercalated nanocomposites, however, silicate layers are sometimes flocculated due to hydroxylated edge-edge interaction of the silicate layers. The length of the oriented collections in the range of 300-800 nm is far larger than the original silicate layer (mean diameter 150 nm) (165, 286, a.9). Such flocculation presumably

Polymer/Layered Silicate Nanocomposites

Intercalated

Intercalated-and-flocculated

Exfoliated

Figure 3 Schematic illustration of three different types of thermodynamically achievable polymer/clay nanocomposites. (Adapted from (a.9), S. Sinha Ray et al., Macromolecules, 2003, 36, 2355, with permission from the American Chemical Society)

is governed by an interfacial energy between polymer matrix and organoclays and controlled by ammonium cation-matrix polymer interaction. The polarity of the matrix polymer is of fundamental importance in controlling the nanoscale structure. (3) Exfoliated nanocomposites: in exfoliated nanocomposites, the individual silicate layers are separated in a continuous polymer matrix by an average distance that totally depends on the layered silicate loading. Usually, the clay content of an exfoliated nanocomposite is much lower than that of an intercalated nanocomposites.

4.2 Characterisation of PLS Nanocomposites The structure of the PLS nanocomposites has typically been established using wide-angle X-ray diffraction (WAXD) analysis and transmission electron microscope (TEM) observations. Due to its ease of use and availability WAXD is most commonly used to probe the PLS nanocomposite structure and sometimes to study the kinetics of the polymer melt intercalation. By monitoring the position, shape and intensity of the basal reflections from the distributed silicate layers, the nanocomposite structure either intercalated or exfoliated may be identified. For example, in the case of exfoliated nanocomposites, the extensive layer separation associated with the delamination of the original silicate layers in the polymer matrix results in the eventual disappearance of any coherent X-ray diffraction from the distributed silicate layers. On the other hand, for intercalated nanocomposites, the finite layer expansion associated with the polymer intercalation results in the appearance of a new basal reflection corresponding to the larger gallery height. Although, WAXD offers a convenient method to determine the interlayer spacing

of the silicate layers in the original layered silicates and in the intercalated nanocomposites (within 1-4 nm), however, little can be said about the spatial distribution of the silicate layers or any structural inhomogeneities in the PLS nanocomposites. Additionally, some layered silicates initially do not exhibit well-defined basal reflection. Thus, peak broadening and intensity decreases are very difficult to study systematically. Therefore, conclusions concerning the mechanism of nanocomposites formation and their structure based solely on WAXD patterns are only tentative. On the other hand, TEM allows a qualitative understanding of the internal structure, spatial distribution of the various phases, and defect structure through direct visualisation. However, special care must be exercised to guarantee a representative crosssection of the sample. The WAXD patterns and corresponding TEM images of three different types of nanocomposites are presented in Figure 4.

5 Types of Polymers for the Preparation of Nanocomposites 5.1 Vinyl Polymer Systems These include the vinyl addition polymers derived from common monomers like: •

methyl methacrylate (MMA) (170, 240, 246, 280, 286, 314, 320, 323, 330, 389, 341, a.16-a.18),

•

methyl methacrylate copolymers (280, 286, 367),

•

other acrylates (322, 325, 392),

7

Polymer/Layered Silicate Nanocomposites

Intercalated

Intercalated-and-flocculated

Exfoliated (a)

(b)

Figure 4 (a) WAXD patterns and (b) TEM images of three different types of nanocomposites

•

acrylic acid (259, a.19),

•

acrylonitrile (AN) (132, 420, a.20, a.21),

In addition, more specialised polymers have also been used like: •

PVA (223, 299, 352, 375, a.11),

styrene (S) (155, 160, 167, 204, 222, 235, 240, 248, 276, 300, 310, 323, 327, 340, 371, 386, 390, 408, a.22, a.23),

•

poly(N-vinyl pyrrolidone) (PVP) (365),

•

polyvinyl pyrrolidinone (55, 318, 353),

•

4-vinylpyridine (224, a.24), and

•

polyvinyl pyridine (224, 331),

•

acrylamide (344, 354).

•

polyethylene glycol (PEG) (a.25),

•

8

Polymer/Layered Silicate Nanocomposites

•

ethylene-vinyl alcohol copolymer (PEVA) (126, a.26),

•

polyvinylidene fluoride (67),

•

poly (p-phenylenevinylene) (a.27),

•

polybutadiene (373),

•

styrene-acrylonitrile copolymer (SAN) (218, 294), and

•

polystyrene-polyisoprene diblock copolymer (133, 317).

5.1.1 PS/LS Nanocomposites Akelah and Moet (390) have used the in situ intercalative polymerisation technique for the preparation of PS/LS nanocomposites. They modified Na+-MMT and Ca+2-MMT with vinylbenzyltrimethyl ammonium cation by the ion exchange reaction and these modified MMTs were used for the preparation of nanocomposites. They first disperse and swell modified clays in various solvent and co-solvent mixtures such as acetonitrile, acetonitrile/toluene and acetonitrile/THF by stirring for 1 hour under N 2 atmosphere. To the stirred solution, S and N,N-azobis (isobutyronitrile) (AIBN) were added, and polymerisation of S was carried at 80 °C for 5 hours. The resulting composites were isolated by precipitation of the colloidal suspension in methanol, filtered off and dried. In this way, intercalated PS/MMT nanocomposites were produced and the extent of intercalation completely depends upon the nature of the solvent used. Although, the PS is well intercalated, a drawback of this procedure remains that the macromolecule produced is not a pure PS but rather a copolymer between S and vinylbenzyltrimethylammonium cations. For the preparation of PS based nanocomposites, Doh and Cho (357) have used more commonly used MMT. They compared the ability of several tetraalkylammonium cations incorporated in Na+-MMT through the exchange reaction to promote the intercalation of PS through the free radical polymerisation of S initiated by AIBN at 50 °C. They found that the structural affinity between S monomer and the surfactant of modified MMT plays an important role in the final structure and the properties of nanocomposites. This concept was nicely employed by Weimer and co-workers (a.23) for the preparation of PS/MMT nanocomposites. They modified Na+-

MMT by anchoring an ammonium cation bearing a nitroxide moiety known for its ability to mediate the controlled/‘living’ free radical polymerisation of S in bulk. The absence of WAXD peaks in the low angle area together with the TEM observations of silicate layers randomly dispersed within the PS matrix attest for the complete exfoliation of the layered silicate. PS was also the first polymer used for the preparation of nanocomposite using the melt intercalation technique with alkylammonium cation modified MMT (408). In a typical preparative method, PS was first mixed with host organoclay powder, the mixture was pressed into a pellet and then heated in a vacuum at 165 °C. This temperature is well above the bulk glass transition temperature of PS ensuring the presence of a polymer melt. The WAXD patterns of the hybrid before heating show peaks characteristic of the pure organoclay and during heating the organoclay peaks were progressively reduced while a set of new peaks corresponding to the PS/LS appeared. After 25 hours, the hybrid shows the WAXD patterns corresponding predominantly to the intercalated structure. Syndiotactic polystyrene (s-PS)/organoclay nanocomposites have also been prepared by the solution intercalation technique by mixing pure s-PS and organoclay with adsorbed cetyl pyridinium chloride (207).

5.1.2 PMMA/LS Nanocomposites Okamoto and co-workers (286, 323) used organically modified smectite clays for the preparation of PMMA/LS and PS/LS nanocomposites. Organically modified smectite clays (SPN and STN) were prepared by replacing Na+-smectite with quaternary ammonium (QA), oligo (oxypropylene)-, diethylmethylammonium cation (SPN) or methyltrioctylammonium cation (STN) by exchange reaction. In a typical synthesis, both lipophilised smectite clays (SPN and STN) were dispersed in MMA and S via ultrasonication at 25 °C for 7 hours to obtain suspensions. After that t-butyl peroxy-2-ethylhexanate and/or 1,1-bis(t-butyl peroxy) cyclohexane as an initiator was added to the suspensions and then free-radical polymerisation was carried out in the dark at 80 °C for 5 hours (for MMA) and at 100 °C for 16 hours (for S) in a silicon oil bath. For comparison the workers also prepared PMMA and/or PS including QA as the references under the same conditions and procedure. WAXD analyses were performed directly from the suspensions of MMA/SPN, MMA/STN and S/SPN, and corresponding nanocomposites.

9

Polymer/Layered Silicate Nanocomposites

been completely exfoliated or delaminated in the suspension. An almost similar pattern was observed in the corresponding PMMA/SPN nanocomposite but with a small remnant shoulder as shown in Figure 5b. Further studies (286) have demonstrated the effect of the nature of co-monomers on the structure of PMMA nanocomposites prepared via in situ free-radical copolymerisation of MMA in the presence of lyophilised smectite clays (each contain 10 wt%). They used three different types of co-monomers (each 1 mol%): N,Ndimethylaminopropyl acrylamide (PAA), N,Ndimethylaminoethyl acrylate (AEA) and acrylamide (AA) for the free-radical polymerisation of MMA. Figure 6 shows TEM pictures of the observed structures. In the case of PMMA-PAA/SPN10 (see Figure 6c), individual silicate layers connected through the edge are clearly observed in the PMMA-PAA matrix and large anisotropy of the dispersed clay is observed. In contrast, the PMMA-AA/SPN10 nanocomposite (see Figure 6d) exhibited less stacking of 4-5 silicate layers with a thickness of the stacking layers of about 5 nm as a fine dispersion in the PMMA-AA matrix. The coherent orders of the silicate layers in this system are higher than that in other systems.

Figure 5 WAXD patterns of various monomer/organoclay suspensions and corresponding polymer/LS nanocomposites: (a) PMMA/STN, (b) PMMA/SPN and (c) PS/SPN. The dashed lines indicate the location of the silicate (001) reflection of organoclay from suspensions and nanocomposites. The asterisk indicates the position of (001) reflections from suspensions and nanocomposites. The arrows indicate a small shoulder or a weak peak. (Reprinted from (323), M. Okamoto et al., Polymer, 2000, 41, 3887, with permission from Elsevier Science Ltd.)

From WAXD patterns of MMA/STN suspension (see Figure 5a), the higher-order peaks of interlayer spacing corresponding to d(002) and d(003) are clearly observed along with the basal spacing d(001) peak, suggesting MMA intercalated into the STN gallery without the loss of layer structure. The corresponding nanocomposite, PMMA/STN exhibits rather broad Braggs peaks, indicating the formation of disordered intercalated structure. In contrast, for MMA/SPN suspension (see Figure 5b), the absence of any Bragg diffraction peaks indicates that the silicate layer has

10

5.1.3 PVA/LS Nanocomposites Strawhecker and Manias (299) have produced PVA/ MMT nanocomposite films. PVA/MMT nanocomposite films were cast from MMT/water suspension where PVA was dissolved. Room temperature distilled water was used to form a suspension of Na+-MMT. The suspension was first stirred for 1 hour and then sonicated for 30 minutes. Low viscosity, fully hydrolysed atactic PVA was then added to the stirring suspensions such that the total solid (silicate plus polymer) was ≤ 5 wt%. The mixtures were then heated to 90 °C to dissolve the PVA, again sonicated for 30 minutes, and finally films were cast in a closed oven at 40 °C for 2 days. The recovered cast films were then characterised by both WAXD and TEM. Both the d-spacing and their distribution decrease systematically with increasing MMT wt% in the nanocomposites.

5.1.4 Block Copolymer/LS Nanocomposites Krishnamoorti (133, 317) prepared block copolymerbased layered silicate nanocomposites. Disordered polystyrene-polyisoprene block copolymer/LS nanocomposites were prepared by solution mixing of appropriate quantities of finely ground dimethyl-

Polymer/Layered Silicate Nanocomposites

dioctadecylammonium cation modified MMT (2C18MMT) and an anionically synthesised monodisperse polystyrene-1,4-polyisoprene (7 mol% 3,4 and 93 mol% 1,4) diblock copolymer (PSPI18) in toluene at room temperature. The homogeneous solution was dried extensively at room temperature and subsequently annealed at 100 °C in a vacuum oven for ~12 hours to remove any remaining solvent and to facilitate complete polymer intercalation between the silicate layers. The intercalation of PS into the silicate layers may be due to the slight Lewis base character imparted by the phenyl ring in PS, leading to favourable interactions with the 2C18-MMT layers. Further, the interlayer gallery spacing for the PSPI18/2C18-MMT composites is independent of the silicate loading. All the hybrids exhibit clear regular layered structure, demonstrated by the presence of the d001 and higherorder diffraction peaks. This independence of gallery height on the silicate loading is consistent with the results obtained by Vaia and coworkers on model PSbased nanocomposite systems.

5.2 Condensation Polymers and Rubbers Several technologically important polycondensates have also been used in nanocomposite preparation with LS. These include: •

Nylon 6 (85, 90, 91, 138, 145, 147, 162, 177, 179, 202, 203, 210, 211, 213, 217, 228, 232, 233, 237, 238, 256, 282, 288, 301, 305, 351, 358, 368, 369, 378, 399, 400, 404, 412, 413, 414, 415, 416, a.28, a.29),

•

several other polyamides (65, 92, 129, 194, 287, 309, 311, 355, 370, 401),

•

poly(ε-caprolactone) (PCL) (88, 102, 124, 141, 152, 154, 378, 380, 398, 409),

•

polyethylene terephthalate (PET) (120, 199, 229, 274, 348, 350, 381, 379, 391, a.30, a.31),

•

polybutylene terephthalate (PBT) (135),

•

polypropylene terephthalate (PPT) (a.32, a.33),

•

polycarbonate (PC) (284, 321, a.34, a.35),

•

PEO (128, 139, 142, 175, 195, 209, 221, 239, 247, 252, 293, 304, 332, 339, 384, 402, 411, 417, a.36-a.38),

Figure 6 TEM images of: (a) PMMA/SPN, (b) PMMA-AEA (1 mol%)/SPN, (c) PMMA-PAA (1 mol%)/SPN, and (d) PMMA-AA (1 mol%)/SPN. Each contains 10 wt% SPN. (Reprinted from (286), M. Okamoto et al., Polymer, 2001, 42, 1201, with permission from Elsevier Science Ltd.)

11

Polymer/Layered Silicate Nanocomposites

•

ethylene oxide copolymers (347),

•

polyethylene imine (a.39),

•

polydimethyl siloxane (PDMS) (241, 250, 316, 329, 363, 396),

•

liquid crystalline polymer (LCP) (148, 285),

•

polybenzoxazole (PBO) (140),

•

butadiene copolymers (231) (345) (297) (296),

•

epoxidised natural rubber (216, 343),

•

epoxy polymer resins (EPR) (95, 96, 130, 137, 143, 193, 201, 249, 255, 261, 277, 281, 283, 313, 364, 366, 388, 395, 403, 405, 407, a.40-a.43),

•

phenolic resins (275, 298),

•

polyurethanes (PU) (118, 136, 171, 184, 215, 225, 270, 272, 326, 356, a.44),

•

polyurethane urea (PUU) (171, 270),

•

polyimides (131, 185, 206, 242, 254, 263, 258, 266, 273, 279, 289, 290, 335, 337, 346, 377, 410, 406),

•

polyamic acid (200, 260, 269, 335, 342),

•

polysulfone (123, 220) and

•

polyetherimide (289).

5.2.1 Nylon/LS Nanocomposites In 1993, Usuki, Fukushima and their colleagues of TCRD successfully prepared, for the first time, exfoliated Nylon 6/LS hybrid (NCH) via in situ polymerisation of ε-caprolactam (see Section 1). TCRD reported (a.8) the ability of α,ω-amino acids (COOH(CH2)n-1-NH2+, with n = 2, 3, 4, 5, 6, 8, 11, 12, 18) and modified Na+-MMT to be swollen by the ε-caprolactam monomer at 100 °C and subsequently to initiate ring opening polymerisation to obtain Nylon 6/MMT nanocomposites. For the intercalation of ε-caprolactam, they chose the ammonium cation of ω-amino acids because these acids catalyse ringopening polymerisation of ε-caprolactam. Liu and co-workers (351) first used this technique for the preparation of commercially available Nylon 6/C18-MMT nanocomposites by using a twin-

12

screw extruder. They prepared nanocomposites with MMT content from 1 to 18 wt%. WAXD patterns and TEM observations respectively indicated that nanocomposites prepared with MMT content of less than 10 wt% leads to the exfoliated structure, but more than 10 wt% MMT leads to the formation of intercalated structure. After that VanderHart and coworkers (202, 203) prepared Nylon 6/LS nanocomposites using the melt intercalation method. Fornes and co-workers (211) have reported the preparation of Nylon 6/LS nanocomposites under molten state using a twin-screw extruder. They used three different molecular grades of Nylon 6 for the preparation of nanocomposites with bis(hydroxyethyl)(methyl)-rapeseed-quaternary ammonium ((HE)2M1R1) modified MMT, and tried to find out any effect of matrix molecular weights on structure, properties, rheology, etc. Nanocomposites were prepared using a Haake, co-rotating, intermeshing twinscrew extruder, which was operated at 240 °C with a screw speed of 280 rpm, and a feed rate of 980 g/h. They also examined the effect of OMLS structure on Nylon 6 nanocomposite morphology and properties (85). In order to understand this, a series of organic amine salts were ion exchanged with Na+-MMT to form OMLSs varying in amine structure or exchange level relative to the MMT. Each OMLS was melt-mixed with a high molecular weight (HMW) Nylon 6 using a twinscrew extruder; some organoclays were also mixed with low molecular weight (LMW) Nylon 6. The structure and corresponding nomenclature of various amine compounds that were used for the modification of Na+-MMT using the ion exchange method are presented in Figure 7. They concluded that three distinct surfactant effects were identified that lead to greater extents of exfoliation, higher stiffness, and increased yield strengths for nanocomposites based on the HMW Nylon 6: (a) one long alkyl tail on the ammonium ion rather than two; (b) methyl groups on the amine rather than 2-hydroxyethyl groups, and (c) an equivalent amount of amine surfactant on the layered silicate as opposed to an excess amount. Gilman and co-workers (105) reported the preparation of Nylon 6- and PS-based nanocomposites of MMT modified with trialkylimidazolium cation in order to obtain high stability of OMLS at high processing temperature. Figure 8 represents the various kinds of imidazolium salts used for the modification of MMT.

Polymer/Layered Silicate Nanocomposites

Cl-

CH3 N+

T(C18)

CH3

HT(C18)

N+

CH3

CH3

CH3

M3T1

M3(HT)1

CH2CH2OH ClN+

R(C22)

Cl-

CH3

Cl-

CH3 HT(C18)

CH3

CH2CH2OH

N+

CH3

HT(C18)

(HE)2M1R1

M2(HT)2 Cl-

Cl-

CH2CH2OH N+

T(C18)

CH2CH2OH C*(C12)

CH3

CH2CH2OH

HT(C18)

N+

CH3

CH2CH2OH

(HE)2M1T1

H

N+

(HE)2M1C*1 (HSO4)-

H

CH3

HT(C18)

CH3

N+

(HSO4)CH3

HT(C18)

M2H1(HT)1

M1H1(HT)2

Figure 7 (a) Molecular structure and nomenclature of amine salts used to organically modify Na+-MMT by ion exchange. Symbols M: Methyl, T: Tallow, HT: hydrogenated tallow, HE:2-hydroxy-ethyl, R: rapeseed, C: cocoalkyl, and H hydrogen designate the substitutents on the nitrogen. (Reprinted from (85), T.D. Fornes et al., Polymer, 2002, 43, 5915, with permission from Elsevier Science Ltd.)

Me

+

N

N R

propyl

X- = Cl-, BF4-

butyl

R=

decyl

Me

hexadecyl Dimethyl alkyl imidazolium salts

Figure 8 Structures of various imidazolium salts used to treat Na+-MMT (Reprinted from (105), J.W. Gilman et al., Chem. Mater., 2002, 14, 3776, with permission from the American Chemical Society)

13

Polymer/Layered Silicate Nanocomposites

For the preparation of nanocomposites they used a mini-extruder, which was operated at 10 °C above the melting point of the polymer with a residence time of 3-5 min and screw speed of 200-300 rpm.

5.2.2 PCL/LS Nanocomposites Messersmith and Giannelis (409) modified MMT using protonated aminolauric acid and dispersed the modified MMT in liquid ε-caprolactone (CL) before polymerising at high temperature. The nanocomposites were prepared by mixing up to 30 wt% of the modified MMT with dried and freshly distilled ε-caprolactone for a couple of hours followed by ring opening polymerisation under stirring at 170 °C for 48 hours. The same authors (398) have also reported on the ε-caprolactone polymerisation inside a Cr+3-exchanged fluorohectorite at 100 °C for 48 hours. Pantoustier and co-workers (88, 102) used this in situ intercalative polymerisation method. They used both pristine MMT and ω-amino dodecanoic acid modified MMT for the comparison of prepared nanocomposites properties. For nanocomposite synthesis, in a polymerisation tube, the desired amount of pristine MMT was first dried under vacuum at 70 °C for 3 hours. A given amount of ε-caprolactone was then added under nitrogen and the reaction medium was stirred at room temperature for 1 hour. A solution of initiator, dibutyl tin dimethoxide or tin (II) 2-ethylhexanolate in dry toluene was added to the mixture in order to reach a [monomer]/[Sn] molar ratio equal to 300. The polymerisation of CL with pristine MMT gives PCL with a molar mass of 4800 g/mol and a narrow distribution. For comparison the authors also conducted the same experiment without MMT but there was no polymerisation of CL. These results demonstrate the ability of MMT to catalyse and to control CL polymerisation, at least in terms of molecular weight distribution, to a remarkably narrow range. For the mechanism of polymerisation, the authors assume that the CL is activated through interaction with acidic sites on the clay surface and the polymerisation is likely to be proceeding via the activated monomer mechanism by the cooperative function of Lewis acidic aluminium and Bronstrated acidic silanol functionalities on the initiator. On the other hand, the polymerisation of CL with protonated ω-amino dodecanoic acid modified MMT, gives a molar mass of 7800 g/mol with a monomer conversion of 92% and again a narrow molecular weight distribution. In other very recent publications (150, 151), the same group prepared PCL/MMT nanocomposites by using in situ ring opening polymerisation of CL using dibutyl tin dimethoxide as an initiator/catalyst.

14

5.2.3 PET/LS Nanocomposites There are many reports on the preparation and characterisation of PET/LS nanocomposites using the in situ polymerisation method. Unfortunately no reports give a detailed description of the preparative method. One report describes the preparation of a PET nanocomposite by in situ polymerisation of a dispersion of organoclay in water; however, characterisation of the resulting composite was not reported (350). This report claims that water serves as a dispersing aid for the intercalation of monomers into the galleries of the OMLS and discloses that a wide variety of small molecules can serve as dispersing aids in place of, or in combination with, water. Imai (120) reported the preparation of higher-modulus PET/expandable fluorine mica nanocomposites with a novel reactive compatibiliser. Details regarding the synthetic route are presented in reference (120). Davis and co-workers (a.31) first reported the preparation of PET-based nanocomposite using the melt intercalation method. They used 1,2-dimethyl3-N-alkyl imidazolium salt modified MMT (hexadecyl-MMT) for the nanocomposite preparation with PET. PET/MMT nanocomposites were compounded via melt blending in a co-rotating mini twin-screw extruder operated at 285 °C. WAXD analyses and TEM (see Figure 9) observations respectively established the formation of mixed delaminated/intercalated structure in the nanocomposites.

5.2.4 PBT/LS Nanocomposites As well as PET/LS systems, this method was successfully applied by Chisholm and co-workers (135) for the preparation PBT/LS nanocomposites. They used sulfonated PBT for the preparation of nanocomposites. Because of the ionic nature of the -SO3Na groups and the expected insolubility of the -SO3Na groups in the polyester matrix, it was thought that the presence of the SO3Na groups may provide a thermodynamic driving force for the production of nanocomposites derived from MMT. But after preparation and characterisation of the nanocomposites it was found that the degree of intercalation was not strongly dependent on the amount of -SO3Na groups, however, the mechanical properties increased significantly with increasing -SO3Na content. This behaviour indicates that with high -SO 3 Na content the number of interactions increases between the clay particles and the matrix via strong specific interactions involving the -SO3Na groups.

Polymer/Layered Silicate Nanocomposites

(a)

50 nm

500 nm

(b)

500 nm

50 nm

Figure 9 TEM images of PET/LS nanocomposites: (a) high levels of dispersion and exfoliation, average tactoids of four sheets per stack and (b) similar levels of dispersion and delamination (Reprinted from (a.31), C.H. Davis et al., J Polym. Sci. Part B Polym. Phys., 2002, 40, 2661, with permission from John Wiley & Sons, Inc.)

5.2.5 PC/LS Nanocomposites Huang (321) reported the synthesis of a partially exfoliated bisphenol A PC nanocomposite using carbonate cyclic oligomers and ditallow dimethylexchanged MMT. WAXD patterns indicate that exfoliation of this organoclay occurs after mixing with the cyclic oligomers in a Brabender mixer for 1 hour at 180 °C. Subsequent ring-opening polymerisation of the cyclic oligomers converts the matrix into the polymer without disruption of the nanocomposite structure. TEM revealed that a little exfoliation is obtained. Mitsunaga and Okamoto (a.34, a.35) have reported the preparation of intercalated PC/LS nanocomposites, using the melt intercalation method in the presence of compatibiliser. The morphology of these nanocomposites and degradation of the PC-matrix after nanocomposite preparation could be controlled by varying the surfactants used for the modification of the clay and compatibilisers. The intercalated PC/LS

nanocomposites exhibited remarkable improvements of mechanical properties when compared with PC without silicate layers. They also conducted foam processing of PC/LS nanocomposites by using supercritical CO2 at 10 MPa in a batch process.

5.2.6 PEO/LS Nanocomposites In 1992, Aranda and Ruiz-Hitzky (417) first reported the preparation of PEO/MMT nanocomposites. They have carried out a series of experiments to intercalate PEO (MW = 105 g/mol) into Na+-MMT using different polar solvents, e.g., mixtures (1:1) of water/methanol and methanol/acetonitrile. In this method the nature of the solvents is very crucial to facilitate the insertion of polymers between the silicate layers, the polarity of the medium being a determining factor for intercalation. The high polarity of water causes swelling of Na+-MMT provoking the cracking of the films. Methanol is not suitable as a solvent for high molecular weight PEO,

15

Polymer/Layered Silicate Nanocomposites

whereas water/methanol mixtures appear to be useful for intercalations, although cracking of the resulting materials is frequently observed. PEO intercalated compounds derived from homoionic M+n-MMT and M+n-hectorite, can satisfactorily be obtained using anhydrous acetonitrile or methanol/acetonitrile mixture as solvents. In addition, the lack of PEO replacement by organic compounds having high affinity toward the parent silicate, such as dimethyl sulfoxide and crown ethers, indicates again the high stability of PEOintercalated nanocomposites. On the other hand, treatment with salt solutions provokes the replacement of the interlayer cations without disturbance of the PEO. For example, Na+ ions in PEO/Na+-MMT are easily replaced by NH 4+ or CH 3 (CH 2 ) 2 NH 3 + ions, after treatment (2 hours) at room temperature with aqueous solution of their chloride, perchlorate and thiocyanate salts (1N solutions), in a reversible process. Various other authors (142, 195) have used the same method and the same solvent for the preparation of PEO/LS nanocomposites. Vaia and co-workers (402) applied this method to intercalate PEO in Na+-MMT layers. Intercalation of PEO in layered silicate was accomplished by heating the PEO with the Na+-MMT at 80 °C. The WAXD patterns before any heating contain peaks characteristic of both Na+-MMT and crystalline PEO. After heating to 80 °C, the intensity of the peaks corresponding to the unintercalated silicate and crystalline PEO is progressively reduced while a set of new peaks corresponding to the PEO-intercalated MMT are observed signifying the completion of intercalation. Recently Shen and co-workers (139) reported the preparation of PEO/OMLS nanocomposites using the melt intercalation technique. In order to find out the effect of thermal treatment on the amount of PEO and polyethylene-polyethylene glycol diblock copolymer (PE-PEG) intercalated into the layers of Na+-MMT and on ionic conductivity of PEO/Na+-MMT, Liao and coworkers (209) have prepared PEO/Na+-MMT and PE-PEG di-block copolymer/Na + -MMT nanocomposites using a melt intercalation technique. It was found that PEO can be intercalated into the layers of Na+-MMT by simple mechanical blending and part of the PE in PE-PEG diblock copolymers was also intercalated into the layers of Na+-MMT. The intercalated amount increases with the thermal treatment time, which ultimately improves the ionic conductivity of the PEO/Na+-MMT nanocomposites.

nematic state. Melt intercalation of a model main chain liquid crystalline copolymer based on 4,4-dihydroxyα-methylstilbene and a 50:50 mole ratio mixture of heptyl/nonyl alkyl dibromide was accomplished by annealing a powder mixture of the polymer and OMLS within the nematic region of the polymer. In another report, Chang and co-workers (148) have prepared nanocomposites of thermotropic liquid crystalline polyester (TLCP) and Cloisite 25A (a commercial organoclay) using a melt intercalation method above the melt transition temperature of the TLCP. Liquid crystallinity of the nanocomposites was observed with OMLS content up to 6 wt%.

5.2.8 PBO/LS Nanocomposites Zhu (204) used phosphonium salt for the modification of clay and then tried to find out the differences between organo ammonium and phosphonium salt treatments of clay fillers in nanocomposites in their effects on thermal stability. This technique was successfully applied by Hsu (140) in order to prepare polybenzoxazole (PBO)/LS nanocomposite from a PBO precursor, polyhydroxyamide (PHA) and an OMLS. The PBO precursor was made by the low temperature polycondensation reaction between isophthaloyl chloride (IC) and 2,2-bis(3-amino-4hydroxyphenyl) hexafluoropropane with an inherent viscosity of 0.5 dl/g. For the preparation of PBO/LS nanocomposite, the OMLS was first dispersed in dimethyacetamide in which PHA was dissolved. The PHA/LS film was obtained from solution casting and dried at 80 °C under vacuum. Finally PBO/LS nanocomposite was obtained by curing the film at 350 °C to form the benzoxazole ring.

5.2.9 EPR/LS Nanocomposites The chemistry of ring opening polymerisation of epoxides to form polyether nanocomposites was followed by studies of both rubbery and glassy thermoset epoxy (EPR)/LS nanocomposites using different types of amine curing agents. The mechanisms leading to the monolayer exfoliation of clay layers in thermoset epoxy systems have been greatly elucidated. In addition, the polymer/LS interfacial properties have been shown to play a dominant role in determining the performance benefits derived from nanolayer exfoliation.

5.2.7 LCP/LS Nanocomposites Vaia (285) reported the reversible intercalation between OMLS and liquid crystalline polymers (LCP) in the

16

Giannelis and co-workers (405) first reported the preparation of epoxy resin based nanocomposites of OMLS. They have analysed the effect of different curing

Polymer/Layered Silicate Nanocomposites

agents and curing conditions on the formation of nanocomposites based on the diglycidyl ether of bisphenol A (DGEBA) and a MMT modified by bis (2-hydroxyethyl) methyl hydrogenated tallow alkylammonium cation. They found that this modified clay dispersed readily in DGEBA when sonicated for a short time period, as determined by the increase in viscosity at relatively low shear rates and the transition of the suspension from opaque to semitransparent. The increase in viscosity was attributed to the formation of a so-called ‘house-of-cards’ structure in which edge-toedge and edge-to-face interactions between dispersed layers form a percolation structure. Wang and Pinnavaia (407) used a series of acidic cations such as H+, NH4+, and acidic onium ions of the type [H3N(CH2)n-1COOH]+, [H3N(CH2)nNH2]+, [H3N(CH2)nNH3]+2 (n = 6 and 12) for the modification of MMT and carried out the polymerisation-delamination process over the temperature range of 198-287 °C. They found that the EPR-clay delamination temperature (PDT) was dependent on the heating rate and nature of the cation used for the modification of the clay. In general, the PDT increased with decreasing cation acidity and basal spacing of the clay. The delamination of MMT in the polymerised epoxy resin was confirmed by X-ray powder diffraction (XRD), as shown by the powder patterns in parts (a) and (b) of Figure 10 where [H3N(CH2)11COOH]+-MMT remains crystalline over the temperature range 25-229 °C. Only the very diffuse scattering characteristic of the

amorphous polyether appears in the XRD pattern of the composite. The absence of a 17 Å peak for [H3N(CH2)11COOH] +-MMT suggests that the clay particles have been exfoliated and the 9.6 Å-thick clay layers dispersed at the molecular level. TEM provides unambiguous evidence for the delamination of the MMT in the polyether matrix. PDT values and thermodynamic data for MMT-polyether nanocomposites formed from bifunctional onium ion MMT and onium ion NH4+, and H+ MMT are presented in Table 3 and Table 4. A group from Australia (137) has reported the morphology, thermal relaxation and mechanical properties of PLS nanocomposites of high-functionality epoxy resins. Three different types of resins were used: bifunctional DGEBA, trifunctional triglycidyl p-amino phenol (TGAP), tetrafunctional tetraglycidyldiamino diphenylmethane (TGDDM) and all were cured with diethyltoluene diamine (DETDA). The structure of the resins and curing agent are presented in Table 5. MMT modified with octadecylammonium cation was used for the preparation of nanocomposites. The morphology of the cured samples was investigated using WAXD and different microscopy techniques. Figure 11(a) shows the WAXD patterns of the MMT concentration series showing that the organoclay with an initial dspacing of 2.3 nm is mainly exfoliated in the DGEBAbased system. On the other hand, high content (10 wt%) OMLSs show intercalated structure, while DGEBAbased systems, resins of higher functionality show distinctive peaks even at low OMLS loading, indicating

Figure 10 (a) XRD powder patterns for a freeze-dried [H3N(CH2)11COOH]+-MMT, (b) [H3N(CH2)11COOH]+-MMT freeze-dried and then heated at 229 °C, and (c) clay-polyether nanocomposite containing 5 wt% [H3N(CH2)11COOH]+-MMT (Reprinted from (407), M.S. Wang et al., Chem. Mater., 1995, 7, 468, with permission from the American Chemical Society)

17

Polymer/Layered Silicate Nanocomposites

Table 3 PDT values and thermodynamic data for polyether/clay nanocomposites formed from bifunctional onium ion-MMTa Initial basal spacing (Å)

PDTb (°C)

Heat of reaction (J/g)

Heat of polymerisationc (kJ/mol)

[H3N(CH2)11COOH]+

17.0 ± 0.1

229 ± 1

572 ± 16

228 ± 6

[H3N(CH2)5COOH]+ [H3N(CH2)12NH3]2+ [H3N(CH2)6NH3]2+ [H3N(CH2)12NH2]+ [H3N(CH2)6NH2]+ a The clay:polymer composition

13.3 ± 0.0

248 ± 1

565 ± 06

225 ± 2

13.4 ± 0.1

271 ± 1

566 ± 08

225 ± 3

13.1 ± 0.1

273 ± 2

568 ± 07

226 ± 3

13.5 ± 0.0

281 ± 2

563 ± 07

224 ± 3

13.2 ± 0.1

287 ± 2

557 ± 03

222 ± 2

Interlayer cation

was 5:95 (w/w). is the onset temperature for epoxide polymerisation-clay delamination at a heating rate of 20 °C/min. c Heat of reaction for two epoxide equivalents. Reprinted from (407), M.S. Wang et al., Chem. Mater., 1995, 7, 468, with permission from the American Chemical Society. b PDT

Table 4 PDT values and thermodynamic data for polyether/clay nanocomposites formed from onium ion, NH4+, and H+ MMT Interlayer cation

Initial basal spacing (Å)

PDTa (°C)

Heat of reaction (J/g)

Heat of polymb (kJ/mol)

[H3N(CH2)11CH3]+

15.9 ± 0.2

198 ± 1

550 ± 3

219 ± 2

[H3N(CH2)5CH3]+

14.9 ± 0.1

287 ± 1

554 ± 6

220 ± 3

NH42+ H+

12.5 ± 0.1

247 ± 1

554 ± 5

220 ± 2

13.9 ± 0.1

231 ± 1

555 ± 12

221 ± 5

PDT is the onset temperature for epoxide polymerization-clay delamination at a heating rate of 20 °C/min and a composite clay:polymer composition of 5:95 (w/w). b Heat of polymerisation for two epoxide equivalents. Reprinted from (407), M.S. Wang et al., Chem. Mater., 1995, 7, 468, with permission from the American Chemical Society. a The

that these nanocomposites have a lower degree of exfoliated structure. WAXD patterns are shown in Figure 11b for TGAP and Figure 11c for TGADDM based nanocomposites of MMT. In the case of any nanocomposite systems, the peak observed at around 2.5 nm correlates to the (002) plane and therefore represents only half the distance of the d-spacing. Figure 12 comprises atomic force microscopy (AFM) phase contrast images of the DGEBA nanocomposite containing 5 wt% layered silicate. Individual layers cannot be seen by AFM as they usually are by the TEM. A striated structure, however, can be seen with increasing phase intervals at the top of the picture. From the AFM images it is evident that silicate layers are

18

not homogeneously distributed in the matrix, some stacked layers are present. Chen and co-workers (130) synthesised epoxy-MMT nanocomposite using a surface initiated method in order to understand the interlayer expansion mechanism and thermal-mechanical properties of these nanocomposites. MMT modified with bis-2-hydroxyethyl methyl tallow ammonium cation (C30B) was used as OMLS for nanocomposite synthesis. 3,4-epoxycyclohexylmethyl3,4-epoxycyclohexane carboxylate was used as the epoxy monomer, and hexahydro-4-methylphthalic anhydride (HHMPA), ethylene glycol (EG), and benzyldimethylamine (BDMA) were respectively used as curing agent, initiator and catalyst during synthesis.

Polymer/Layered Silicate Nanocomposites

Table 5 Epoxy resins and hardener as used for nanocomposite synthesis Substance

Formula

DGEBA

CH3

O CH2

CHCH2O

O

C

OCH2CH

CH2

CH3

TGAP

O O CH2

CHCH2O

CH2CH

CH2

CH2CH

CH2

N

O

TGDDM

O

O CH

CH2

CH2 N

CH2

CH

CH2

CH

CH2

CH2

CH

CH2

N

CH2

CH2

O

O

DETDA

CH3

CH3 NH2

CH3CH2

CH2CH3

H2N

CH3CH2

NH2

CH2CH3

NH2

Reprinted from (137), O. Becker et al., Polymer, 2002, 43, 4365, with permission from Elsevier Science Ltd.

The curing mechanism for an epoxy-anhydride system with an alcohol initiator is shown in Figure 13. Amine catalysts like BDMA were added to the mixture to accelerate the reaction by facilitating the ring opening of epoxy groups. Several published papers indicate that intragallery onium ions can catalyse the epoxy curing reaction and thus lead to favourable conditions for obtaining exfoliated PLS nanocomposites. Chen and co-workers (130) verified that the crosslinking reactions in the presence of C30B were due to hydroxy initiation and not due to catalytic reactions. The extent of reaction of a resin containing C30B was compared to the extent of reaction for a neat resin and resins containing either EG or BDMA. Time-resolved high-temperature-XRD is used to probe the expansion behaviour of the silicate layers during curing of the PLS nanocomposites. In Figure 14 the changes in d-spacing are plotted against the isothermal cure time for various clay loadings and cure temperature. On the basis of various characterisation methods, the authors proposed an exfoliation mechanism for surface-

initiated epoxy nanocomposites consisting of three stages. In the first stage, the interlayer expansion induced by intragallery polymerisation must overcome any polymer chains that bridge the silicate layers. The interlayer expansion cannot proceed beyond the first stage if the number of bridging units becomes too great. The second stage was characterised by a steady and linear increase in interlayer spacing and accounts for the majority of the total expansion realised. In this stage, the silicate layers could be monitored via isothermal differential scanning calorimetry experiments. Also, for samples that exhibited a large increase in interlayer expansion, it was found that the activation energy associated with the interlayer expansion was less than the activation energy associated with the curing. The reverse was true for samples that showed no increase in interlayer spacing. In the third stage, the interlayer expansion slowed then stopped, and in some cases decreased slightly. This was ascribed to the evolving modulus of the extragallery polymer such that the interlayer expansion stopped when the modulus of the extragallery polymer became equal to or exceeded the modulus of the intragallery polymer.

19

Polymer/Layered Silicate Nanocomposites

(a)

(b)

(c)

Figure 11 WAXD patterns of (a) DETDA cured DGEBA nanocomposites, (b) DETDA cured TGAP nanocomposites and (c) DETDA cured TGDDM nanocomposites containing 0-10 wt% organoclay (Reprinted from (137), O. Becker et al., Polymer, 2002, 43, 4365, with permission from Elsevier Science Ltd.)

Figure 12 Phase contrast AFM images of DETDA cured DGEBA containing 5 wt% organoclay (Reprinted from (137), O. Becker et al., Polymer, 2002, 43, 4365, with permission from Elsevier Science Ltd.)

20

Polymer/Layered Silicate Nanocomposites

O

O HO O

OH

+ O OH

OH

O

O HO O O O O

BDMA

OH O

Figure 13 Schematic illustration of generalised curing reaction involving the epoxy monomer, HHMPA, EG, and BDMA (Reprinted from (130), J.S. Chen et al., Polymer, 2002, 43, 4895, with permission from Elsevier Science Ltd.)

(a)

(b)

(c) Figure 14 Changes in d001 as a function of the curing time and temperature: (a) 5, (b) 10, and (c) 15 wt% silicate loading. The dashed lines denote the quantitative detection limit of the XRD setup (Reprinted from (130), J.S. Chen et al., Polymer, 2002, 43, 4895, with permission from Elsevier Science Ltd.)

21

Polymer/Layered Silicate Nanocomposites

5.2.10 PU/LS Nanocomposites Chen (a.44) has used a PCL-based nanocomposite synthesis technique for the preparation of novel segmented PU/LS nanocomposites from diphenylmethane diisocyanate, butanediol and preformed polycaprolactone diol. Although the mechanism proposed for the chemical link between the nanofiller surface and the polymer does not appear appropriate, they succeeded in producing a material where the nanofiller acts as a multifunctional chain extender inducing the formation of star-shaped segmented polyurethane. Biomedical PUU/MMT (modified with dimethyl ditallow ammonium cation) nanocomposites were prepared by adding organoclay suspension in toluene drop-wise to a solution of PUU in N,N-dimethylacetamide (DMAC) (270). The mixture was then stirred overnight at room temperature. The solution was degassed, and films were cast on to round glass Petri dishes. The films were airdried for 24 hours and subsequently dried under vacuum at 50 °C for 24 hours. WAXD analyses indicated the formation of intercalated nanocomposites but they did not show any TEM photographs.

solution of polyamic acid and a DMAC dispersion of MMT modified with dodecylammonium cation. Table 6 shows the dispersibility of various kinds of organically modified MMTs in DMAC and the average diameter of organophilic MMTs obtained from dynamic light scattering experiments. In the case of 12CH3MMT, the MMT appeared to disperse in DMAC homogeneously and the average diameter of the dispersed MMT particles was the smallest of all. Another interesting aspect is that as the carbon number of the surfactant increases, the hydrophilicity of the organophilic MMT decreases.

5.3 Polyolefins PP (149, 158, 169, 180, 181, 187, 197, 198, 205, 208, 214, 227, 230, 262, 268, 271, 278, 295, 302, 319, 372, 374, 385, a.45), polyethylene (PE) (115, 134, 164, 219, 226, 251, 334, 349, 362), copolymers like ethylenevinyl acetate copolymer (EVA) (127, 156, 182, 192, 234) and ethylene-propylene-diene terpolymer rubber (EPDM) (163) have also been used in nanocomposites.

5.3.1 PP/LS Nanocomposites 5.2.11 Polyimide/LS Nanocomposites Yano (184) has prepared polyimide/MMT nanocomposites from a dimethylacetamide (DMAC)

Tudor and co-workers (a.45) used the in situ intercalative polymerisation method for the preparation of PP/LS nanocomposites. They have demonstrated the ability of a soluble metallocene

Table 6 Dispersibility and average diameter of organically modified MMT in DMAC Dispersibility of organophilic MMT in DMAC

Average diametera (μm)

Not dispersible

-

Dispersible

0.44

Ammonium salt of 12-aminododecanoic acid (12COOH-MMT)

Partly dispersible

3.75

n-Decyltrimethylammonium chloride (C10A-MMT)

Partly dispersible

0.61

n-Dodecyltrimethylammonium chloride

Not dispersible

-

n-Hexadecyltrimethylammonium chloride

Not dispersible

-

n-Dioctadecyldimethylammonium chloride

Not dispersible

-

n-Trioctylmethylammonium chloride

Not dispersible

-

n-Benzyltrimethylammonium chloride

Not dispersible

-

Intercalated salts n-Octyltrimethylammonium chloride Ammonium salt of dodecylamine (12CH3-MMT)

a Values

of average diameter are much bigger than 200 nm, because an average diameter from light scattering measurement includes solvent around a substance.

22

Polymer/Layered Silicate Nanocomposites

catalyst to intercalate inside silicate layers and to promote the coordination polymerisation of propylene. A synthetic hectorite (Laponite RD) was first treated with methylaluminoxane (MAO) in order to remove all the acidic protons and to prepare the interlayer spacing to receive the transition metal catalyst. It should be noted that MAO is commonly used in association with metallocenes to produce coordination catalysts active in olefin polymerisations. In this first treatment step, WAXD analysis showed no noticeable increase of the layer spacing, although the diffraction peak broadened slightly, but the increase in Al content and complete disappearance of Si-OH signals from IR-spectra indicate MAO reaction/adsorption inside the layered silicate galleries. Upon the addition of the metallocene catalyst ([Zr(η-C5H5)Me(THF)]+), a cation exchange reaction occurs between Na+ in MAO treated hectorite and the metallocene catalyst as demonstrated by an increase in the interlayer spacing of 0.47 nm, consistent with the size of the species. Details are shown in Figure 15. Using a synthetic fluorinated mica-type layered silicate that is deprived from any protons in the galleries; the catalyst was even intercalated directly within the silicate layers without the need of MAO treatment. These two modified layered silicates catalysed the polymerisation of propylene with reasonably high activity when contacted with an excess of MAO, producing PP oligomers. Unfortunately, the authors did not report any characterisation of these composites, so one cannot discuss the morphology.

Usuki and co-workers (385) reported a novel approach to prepare PP/LS nanocomposites using functional oligomer with polar telechelic OH groups (PP-OH) as compatibiliser. In this approach, first PP-OH was intercalated between the layers of 2C18-MMT and the second step was the melt mixing of PP-OH/2C18-MMT with PP, a nanocomposite with intercalated structure was obtained. A further study by the same group (374) reported the preparation of PP/MMT nanocomposites by melt blending of PP, maleic anhydride grafted PP oligomer (PP-MA) and clays modified with stearylammonium, using a twin-screw extruder. In their study, they used two different types of maleic anhydride modified PP oligomer with different amounts of maleic anhydride groups and two types of OMLSs to understand the miscibility effect of the oligomers on the dispersibility of the OMLS in PP matrix, and to study the effect of hybridization on their mechanical properties when compared with neat PP and PP/LS nanocomposites without oligomers. Okamoto and co-workers (227) prepared PP/MMT nanocomposites using the same method as the previous authors. For example, a mixture of PP-MA (0.2 wt% MA) and C18-MMT was melt extruded at 200 °C in a twin-screw extruder. They prepared nanocomposites with three different amount of OMLS content (inorganic part) of 2, 4 and 7.5 wt%, which were correspondingly abbreviated as PPCN2, PPCN4 and PPCN7.5 respectively. WAXD patterns clearly established the formation of near to exfoliate structure with PPCN2, disordered intercalated nanocomposite

Figure 15 Schematic illustration of the modification and ion exchange of Laponite with [Zr(h-C5H5)2Me(THF)]BPh4 and propylene polymerisation. Details regarding the reagent and conditions are given in the relevant reference. (Reprinted from (a.45), J. Tudor et al., Chem. Commun., 1996, 2031, with permission from Royal Society of Chemistry)

23

Polymer/Layered Silicate Nanocomposites

(a) PPCN2

(b) PPCN7.5

Figure 16 A schematic illustration of the dispersed clay structure and the inter-fibrillar structure of PPCNs with: (a) 2 wt%, and (b) 7.5 wt% MMT. (Reprinted from (227), P.H. Nam et al., Polymer, 2001, 42, 9633, with permission from Elsevier Science Ltd.)

in the case of PPCN4, while PPCN7.5 showed ordered intercalated structure. In order to understand the hierarchical structure of PPCNs they also used polarising optical microscopy, light scattering and also small angle X-ray diffraction along with WAXD and TEM. On the basis of these analyses they demonstrated the dispersed clay and inter-fibrillar structure of PPCNs. A schematic illustration of this structure is presented in Figure 16. Manias and co-workers (205) reviewed the preparation of PP/organically modified MMT, having a coexisting intercalated and exfoliated structure, by the melt intercalation technique. In order to prepare nanocomposites they applied two different techniques: (a) by introducing functional groups in PP and using common alkylammonium MMT, and (b) by using neat/ unmodified PP and a semi-fluorinated surfactant modification of the silicates.

5.3.2 PE/LS Nanocomposites PE/LS nanocomposites have been prepared by the in situ intercalative polymerisation of ethylene using the so-called polymerisation filling technique (164). Pristine MMT and hectorite were first treated with trimethylaluminium-depleted methylaluminoxane before a Ti-based constrained geometry catalyst was attached. The nanocomposite was formed by addition and polymerisation of ethylene. In the absence of a chain transfer agent, ultra high molecular weight

24

polyethylene was produced. The tensile properties of these nanocomposites were poor and essentially independent of the nature and content of the silicate. Adding hydrogen during ethylene polymerisation decreased the molecular weight of the polyethylene with parallel improvement of the mechanical properties. The formation of exfoliated PE/LS nanocomposites was established using WAXD and TEM analyses. In another report, Heinemann and coworkers (334) prepared polyolefin/LS nanocomposites using this method. Maleic anhydride (MA) grafted polyethylene (PE-MA)/LS nanocomposites were also prepared by the melt intercalation technique (219). The extent of exfoliation and intercalation completely depends on the hydrophilicity of polyethylene grafted with MA and the chain length of the organic modifier in the clay. When the number of methylene groups in the alkylamine (organic modifier) was larger than 16, exfoliated nanocomposites were obtained. When the maleic anhydride grafting level was higher than about 0.1 wt% exfoliated nanocomposites were obtained, with the LS modified with dimethyl dehydrogenated tallow ammonium cation or octadecylammonium cation.

5.4 Speciality Polymers In addition to the above mentioned conventional polymers, several interesting developments have also been taking place in the preparation of PLS

Polymer/Layered Silicate Nanocomposites

nanocomposites with some speciality polymers including the N-hetrocyclic polymers like polypyrrole (PPY) (69, 186, 187, 188, 189, 190, 191, 397, a.46, a.47), poly(N-vinylcarbazole) (PNVC) (336, 361), and polyaromatics such as polyaniline (PANI) (166, 168, 243, 244, 253, 267, 291, 292, 306, 333), poly(pphenylene vinylene) (245, 328) and related polymers (265). PNVC is well known for its high thermal stability and characteristic optoelectronic properties. Some research has also been initiated with liquid crystalline polymer based nanocomposites (148, 285) and hyperbranched polymers (HBP) (174).

arising from the dissociation of interlayer water molecules coordinated to the exchangeable cations (361). Yet, another possibility, especially with NVC, was that the transition metal oxides (Fe2O 3/TiO2) present in MMT could also lead to cationic initiation of NVC. The same authors subsequently reported that direct interaction of MMT with pyrrole (PY) led only to ca. 5% yield of PPY in 3 hours while aniline (ANI) could not be polymerised by MMT (a.47). According to them, such a trend is possibly not surprising since NVC is relatively more susceptible to cationic polymerisation compared to the latter monomers (336).

5.4.1 PANI/LS Nanocomposites

5.5 Biodegradable Polymers

Nanocomposite formation was carried out by oxidative polymerisation of aniline in a PY/MMT-water system using FeCl3 and ammonium peroxodisulfate (306, a.47), as oxidant respectively in two systems.

Recently, some groups have studied the preparation, characterisation and materials properties of various kinds of biodegradable polymers/LS nanocomposites having properties suitable for a wide-range of applications. So far biodegradable polymers used for the preparation of nanocomposites are:

Kim and co-workers (333) used this method for the preparation of PANI/MMT nanocomposite using dodecylbenzenesulfonic acid (DBSA) and camphorsulfonic acid (CSA) as dopant. In a typical synthesis method, Na+-MMT was first dispersed in an aqueous medium and then sonicated by using an ultrasonic generator. The DBSA or CSA dopants were dissolved in distilled water and mixed with ANI monomer solution at a 1:1 molar ratio; then, the emulsion solutions were mixed in a 4-neck reactor by stirring while the temperature was kept at 25 °C. The oxidant initiator, (NH4)2S2O8 solution was dropped into the reactor. The WAXD analysis clearly indicated the formation of intercalated nanocomposites.

• polylactide (PLA) (9, 50, 54, 60, 64, 81, 110, 383, a.4, a.48, a.49), • polybutylene succinate (PBS) (a.50-a.52), • PCL (88, 102, 124, 141, 152, 154, 378, 380, 398, 409), • unsaturated polyester (307, 360), • polyhydroxybutyrate (376) and • aliphatic polyester (122, 146, 153, 161, 257).

5.4.2 PNVC/LS Nanocomposites 5.5.1 PLA/LS Nanocomposites Sinha Ray (361) first reported the preparation of PNVC/MMT nanocomposites by direct polymerisation of N-vinylcarbazole (NVC) (solid or in solution) in the presence of MMT without the use of any free radical initiator. Melt polymerisation of NVC in MMT (at 70 °C) as well as solution (in benzene) polymerisation of NVC in the presence of MMT at 50 °C resulted in the formation of PNVC/MMT nanocomposite with intercalated structure. On repeated benzene extraction of prepared nanocomposites, intercalated PNVC could not be removed, while all the surface-adsorbed PNVC was extracted with benzene. WAXD analyses confirmed intercalation of PNVC in MMT interlayer galleries. The initiation in the NVC/MMT system was suggested to be cationic involving Brønstrated acid sites in MMT

Sinha Ray and co-workers (a.48, a.49) first reported the preparation of intercalated PLA/LS nanocomposites. For PLA clay nanocomposites (PLACNs) preparation C18-MMT and PLA were first dry mixed by shaking them in a bag. The mixture was then melt-extruded by using a twin-screw extruder operated at 190 °C to yield very light grey colour strands of PLACNs. Nanocomposites loaded with a very small amount of oligo-PCL as a compatibiliser were also prepared in order to understand the effect of oligo-PCL on the morphology and properties of PLACNs (a.48). The compositions of various nanocomposites of PLA with C18-MMT are summarised in Table 7. Figure 17 shows the TEM photographs of the nanocomposites corresponding to

25

Polymer/Layered Silicate Nanocomposites

Table 7 Composition and characteristic parameters of various PLACNs based on PLA, oligo-PCL and C18-MMT Composition, wt% Sample PLA

oligo-PCL

C18-MMTb

Mw × 10-3 (g/mol)

Mw/Mn

Tg (°C)

Tm (°C)

χc c (%)

PLACN1

97

3 [2.0]

178

1.81

60.0

169

50.65

PLACN2

95

5 [3.0]

185

1.86

60.0

170

39.01

PLACN3

93

7 [4.8]

177

1.69

59.8

170

43.66

PLACN4

94.8

0.2

5 [3.3]

181

1.76

58.6

170

41.47

PLACN5

94.5

0.5

5 [3.3]

181

1.76

57.6

169

32.91

PLACN6

93

2.0

5 [2.8]

180

1.76

54.0

168

-

PLACN7

92

3.0

5 [2.4]

181

1.77

51.0

168

-

PLAa

100

187

1.76

60.0

168

36.24

PLA1

99.8

0.2

180

1.76

58.0

168.5

46.21

PLA2

99.5

0.5

180

1.76

57.0

168.8

52.51

PLA3

98

2.0

180

1.76

54.7

169

-

a Mw and polydispersity index of extruded PLA (at 190 °C) are 180 × 103 (g/mol) and 1.6 respectively. b Value in the parenthesis indicates the amount of clay (inorganic part) content after burning. c The degree of crystallinity.

(a)

(b)

2 μm

(c)

2 μm

(d)

500 nm

500 nm

Figure 17 TEM bright field images: (a) PLACN2 (x10000), (b) PLACN4 (x10000), (c) PLACN2 (x400000), and (d) PLACN4 (x40000). The dark entities are the cross sections of intercalated organoclay, and the bright areas are the matrices. (Reprinted from (a.48), S. Sinha Ray et al., Macromolecules, 2002, 35, 3104, with permission from the American Chemical Society)

26

Polymer/Layered Silicate Nanocomposites

the WAXD patterns. On the basis of WAXD analyses and TEM observation, Sinha Ray and co-workers calculated form factors (see Table 8), i.e., average length (L clay ) and thickness (dclay) of the stacked intercalated silicate layers, and the correlation length (ξclay) between them. These data clearly established that silicate layers of the clay were intercalated and randomly distributed in the PLA-matrix. Incorporation of a very small amount of oligo-PCL as a compatibiliser in the nanocomposites lead to a better parallel stacking of the silicate layers and also much stronger flocculation due to the hydroxylated edge-edge interaction of the silicate layers. Owing to the interaction between clay platelets and the PLA-matrix in the presence of a very small amount of oligo-PCL, the disk-disk interaction plays an important role in determining the stability of the clay particles and hence the enhancement of the mechanical properties of such nanocomposites.

They prepared a series of PLACNs with various types of OMLS in order to investigate the effect of OMLS on the morphology (50, 54), properties and biodegradability of PLACNs. Four different types of pristine layered silicates were used and each of them was modified with a different type of surfactant. Details of the various types of organoclay used by them are presented in Table 9. On the basis of WAXD analyses and TEM observations, the authors concluded that four different types of PLACNs were formed. Ordered intercalated-and-flocculated nanocomposites were obtained when ODA was used as organoclay, disordered intercalated structure in the case of PLA/SBE4 nanocomposite, PLA/SAP4 nanocomposite was a near to exfoliate nanocomposite, while co-existence of stacked intercalated and exfoliated nanocomposite structure was found with PLA/MEE4 nanocomposite. So the nature of the OMLS has a strong effect on the final morphology of PLA-based nanocomposites.

Table 8 Comparison of form factors between PLACN2 and PLACN4 obtained from WAXD patterns and TEM observations Form factors

PLACN2

PLACN4

d001 (nm)

3.03

2.98

dclay (nm)

13

10

dclay (nm)

38 ± 17.25

30 ± 12.5

Lclay (nm)

448 ± 200

659 ± 145

Lclay/dclay

12

22

ξclay (nm)

255 ± 137

206 ± 92

WAXD

TEM

Table 9 Specifications and designation of organoclay used for the preparation of PLACNs Pristine clay

Particles length (nm)

CEC (mequiv/100 g)

Organic salt used for the modification of clay

Suppliers

ODA

MMT

150-200

110

Octadecylammonium cation

Nanocor Inc., USA

SBE

MMT

100-130

90

Trimethyloctadecylammonium cation

Hojun Yoko Co., Japan

MEE

Synthetic F-mica

200-300

120

Dipolyoxyethylene alkyl(coco) methylammonium cation

CO-OP Chemicals, Japan

SAP

Saponite

50-60

86.6

Tributylhexadecylphosphonium cation

CO-OP Chemicals, Japan

Clay codes

27

Polymer/Layered Silicate Nanocomposites

In very recent work, Okamoto and Maiti (81) have prepared a series of PLACNs with three different types of pristine layered silicate such as saponite, MMT and mica, and each of them were modified with alkylphosphonium salts having various chain lengths. In their work they first tried to find out the effect of alkylphosphonium modifier of different chain lengths on the properties of OMLS and how the different clays behave having the same organic modifier. They also looked at the effects of dispersion, intercalation, and the aspect ratio of the clay on material properties. From the WAXD patterns it is clearly observed that the d-spacing (001) increases with increasing modifier chain length and for a fixed modifier it increases with increasing lateral dimension of the clay particle. Two reasons were suggested for this type of behaviour: one is the CEC value and the other is the lateral size of various pristine layered silicates, and in both cases layered silicates follow this order mica > MMT > saponite. According to the authors, out of the two factors, the former factor is more important in controlling the d-spacing/stacking of silicate layers than the latter. Since mica has high lateral size and also has high amounts of surfactant molecules due to its high CEC value, surfactant chains inside the intergallery have restricted conformation due to physical jamming. This physical jamming is said to be smaller in the case of saponite due to its lower CEC and smaller lateral size. Different types of OMLS, based on TEM and WAXD analyses, are schematically illustrated in Figure 18. Another important factor is that the coherency of the OMLS increases with increasing lateral dimension of the clay. For one clay system, they reported that for saponite with a different modifier, the coherency is almost the same. It is evident that stacking of OMLS increases with the dimension and CEC of the clay and it is maximum in the case of mica. It is believed

that out of the two factors, the density of organomodification (CEC) plays the more important role in determining the d-spacing/stacking of silicate layers.

5.5.2 PBS/Clay Nanocomposites Polybutylene succinate (PBS) is an aliphatic thermoplastic polyester with many interesting properties, including biodegradability, melt processability, and thermal and chemical resistance. Although the above properties show potential applications of PBS, some of the other properties such as softness, gas barrier properties, flexural properties, etc., are frequently not good enough for a wide range of applications. Sinha Ray and Okamoto (a.50) first reported the preparation of PBS/MMT nanocomposites (PBSCNs) by simple melt extrusion of PBS and OMLS, having properties suitable for a wide range of applications. MMT modified with octadecylammonium chloride was used as the organoclay for nanocomposites preparation. In recent publications (a.51, a.52), the same authors also reported details of a study on structure-property relationships for PBSCNs. Very recently, Lee and co-workers (161) reported the preparation of biodegradable aliphatic polyester (APES)/OMLS nanocomposites using a melt intercalation method. Two kinds of organoclays, Cloisite 30B and Cloisite 10A, with different ammonium cations located in the silicate galleries, were chosen for nanocomposite preparation. According to the authors, there may be more hydrogen-bonding interaction between APES and hydroxyl groups in the galleries of Cloisite 30B nanocomposites than for the APES/Cloisite 10A nanocomposites.

Figure 18 Schematic representation of organoclays with C16 ion (Reprinted from (81), P. Maiti et al., Chem. Mater., 2002, 14, 4654, with permission from the American Chemical Society)

28

Polymer/Layered Silicate Nanocomposites

6 Properties of PLS Nanocomposite Materials 6.1 Dynamic Mechanical Analysis (DMA) In the temperature dependence of storage modulus G′ and loss factor tan δ of various polymer/clay nanocomposites (PCNs) (such as PP/LS, PMMA/LS, Nylon 6/LS, PBS/LS and PLA/LS), below the glass transition region, samples exhibit high G′ and a substantial drop in G′ with increasing temperature. G′ in the glassy region below Tg is approximately 50-100% higher in the nanocomposite compared with the blend systems without clays. The shift of tan δ reaches to higher temperatures and decrease of the value indicates an increase in nanocomposite Tg. In some cases, the magnitude of the shift estimated by

tan δ is about 10 °C or more (280). These results indicate that the interaction between the polymer matrix and silicate layers at the interface could suppress the mobility in the polymer segments near the interface. That is, intercalated nanocomposites are formed. The large aspect ratio of the structural hierarchy on the nanoscale level might lead to such large enhancement in G′ throughout the glassy and rubbery region. The temperature dependence of G′, G′′ and tan δ of the PP/LS system (PPCNs) have been reported (Figure 19) (227). For all PPCNs, there is a strong enhancement of moduli in the investigated temperature range, which indicates the plastic and the elastic response of PP towards deformation is strongly influenced by the presence of organoclay. Below the Tg, the enhancement of G′ is clear in intercalated PPCNs.

Figure 19 Temperature dependence of G′, G′′ and tan δ for PP-MA matrix and various PPCNs (Reprinted from (227), P.H. Nam et al., Polymer, 2001, 42, 9633, with permission from Elsevier Science Ltd.)

29

Polymer/Layered Silicate Nanocomposites

Figure 20 Plots of G′PPCN / G′PP-MA vs. volume% of clay for PPCNs. The value of the Einstein coefficient (kE) is shown in the box. The theoretical lines show the results calculated by Halpin-Tai’s expression with various kE. (Reprinted from (227), P.H. Nam et al., Polymer, 2001, 42, 9633, with permission from Elsevier Science Ltd.)

The LS content dependence of G′ has also been reported (Figure 20) (227). The ratio of G′PPCN/G′PP-MA, G′PPCN and G′PP-MA are the moduli of the intercalated PPCNs and the PP-MA, respectively. The large reinforcement in G′ is observed in the figure. The essential factor governing the enhancement of mechanical properties is the aspect ratio of the dispersed silicate particles. According to Halpin and Tai’s theoretical expression on the enhancement of G′ (419), the Einstein coefficient (kE) was estimated by selecting an appropriate value for best fit to the experimentally obtained G′PPCN/ G′PP-MA versus volume fraction of the clay plots. The estimated values of kE are about 60 for PPCN4, and about 31 for PPCN2 and PPCN7.5. In the intercalated PPCNs, the explanation for the enhancement of G′ by only the kE factor as discussed in previous case of PPMA/LS nanocomposites (286) is hampered because each PPCN exhibits a different value of kE, despite the different silicate content. In the case of intercalated PPCNs, the enhancement of G′ is due to both the degree of the intercalation and the aspect ratio of the dispersed clay particles. The two dimensional aspect ratio of the dispersed silicate (clay) particles L clay /d clay estimated from TEM observation are reported to be 37 for PPCN2, 20 for PPCN4 and 12 for PPCN7.5. In PPCN4, despite the lower value of Lclay/dclay compared to PPCN2 and low addition of the clay compared to PPCN7.5, this

30

nanocomposite shows the highest value of kE, suggesting that much higher efficiency of the intercalation for the reinforcement is attained. Similar results were also reported in PBS/LS nanocomposites (a.50). The remarkable improvement in G′ related to the strong interaction between matrix and organoclay was clearly observed in the case of Nylon 6/LS nanocomposites by the author. Table 10 represents the temperature dependence of G′ and the thermal expansion coefficient (α) of the Nylon 6 matrix and various nanocomposites (N6CNs). The results of the dynamic temperature ram test for neat Nylon 6 and various N6CNs are shown. All N6CNs show very high increment of moduli at all temperature ranges. The increment in G′ directly depends upon the aspect ratio of dispersed clay particles. This is also clearly observed in the case of PBSCNs. The temperature dependence of the G′ of PBS and various PBSCNs have been reported (a.51). The nature of the enhancement of G′ in PBSCNs with temperature is somewhat different from wellestablished intercalated PPCNs (227) and well-known exfoliated N6CN systems (415). In the latter system, there is a maximum of 40-50% increment of G′ compared to that of the matrix at well below Tg, and above Tg there is a strong enhancement (>200%) in G′. This behaviour is common for nanocomposites tested so far, and the reason is the strong reinforcement effect of the clay particles

Polymer/Layered Silicate Nanocomposites

Table 10 Summary of DMA test for Nylon 6 and various Nylon 6 clay nanocomposites (N6CNs) under different temperature ranges 0 °C

25 °C

50 °C

100 °C

150 °C

200 °C

α × 105 (cm/cm. °C)

9.5

12

14

22

31

48

G′ (GPa)

1.04

0.94

0.52

0.16

0.11

0.065

a x 105 (cm/cm. °C)

8.9

9.7

11

16

22

60

G′/GPa

1.2

1.1

0.8

0.41

0.27

0.01

α × 105 (cm/cm. °C)

6.4

6.6

8.7

8. 5

14

67

G′ (GPa)

1.9

1.8

1.2

0.74

0.52

0.18

α × 105 (cm/cm. °C)

7.1

7.7

9.8

11

15

42

G′ (GPa)

1.4

1.3

0.95

0.56

0.38

0.14

Sample

Term

Nylon 6

N6CN1.6

N6CN3.7

N6CN4.4

above Tg when materials become soft. However, in the case of PBSCNs, the order of enhancement of G′ is almost the same below and above the Tg, and this behaviour may be due to the extremely low Tg (-29 °C) of the PBS matrix. In the temperature range of -50 °C to -10 °C, the increments in G′ are 18% for PBSCN1, 31% for PBSCN2, 67% for PBSCN3 and 167% for PBSCN4 compared to that of neat PBS. Furthermore, at room temperature, PBSCN3 and PBSCN4 show higher increments in G′ of 82% and 248%, respectively, compared with neat PBS, while the G′ values of PBSCN1 and PBSCN2 are 18.5%

and 44% higher. At 90 °C, only PBSCN4 exhibits a very strong enhancement of G′ compared to that of the other three PBSCNs. In Figure 21, Okamoto summarised the clay content dependence of G′ of various types of nanocomposites obtained well below the Tg. The Einstein coefficient, kE derived by using Halpin and Tai’s theoretical expression modified by Nielsen is shown in the Figure, and represents the aspect ratio (Lclay/dclay) of dispersed clay (silicate) particles without intercalation. From this

Figure 21 Plots of G′nanocomposite / G′′matrix vs. volume% of clay for various nanocomposites. The Einstein coefficient (kE) is shown as the number in the box. The lines show the calculated results from Halpin and Tai’s theory with various kE.

31

Polymer/Layered Silicate Nanocomposites

Figure 22 Formation of hydrogen bonds between PBS and clay, which leads to the flocculation of the dispersed silicate layers. (Adapted from (a.9), S. Shinha Ray. et al., Macromolecules, 2003, 36, 2355, with permission from the American Chemical Society)

Figure, it is clearly observed that PBSCNs show very high increment in G′ compared to other nanocomposites having the same content of clay in the matrix. PPCNs are well known for intercalated systems, N6CNs are well-established exfoliated nano-composites, PLACNs are intercalated-and-flocculated nanocomposites, while PBSCNs are intercalated-andextended flocculated nanocomposite systems (a.51, a.52). Due to the strong interaction between hydroxylated edge-edge groups, the clay particles are sometimes flocculated in the polymer matrix. As a result of this flocculation the length of the silicate particles increases enormously and hence the overall aspect ratio. For the preparation of high molecular weights PBS, di-isocyanate end-groups are generally used as a chain extender. These isocyanate end-groups chain extenders make urethane bonds with hydroxy terminated low molecular weight PBS, and each high molecular weight PBS chain contains two such bonds. These urethane type bonds lead to strong interaction with the silicate surface by forming hydrogen bonds and hence strong flocculation (see Figure 22). For this reason, the aspect ratio of dispersed clay particles is much higher in the case of PBSCNs compared to all nanocomposites, and hence the high enhancement of modulus.

formation of exfoliated nanocomposites, exhibit a drastic increase in the tensile properties at rather low filler content. The main reason for the drastic improvement of modulus in the case of N6CNs is the strong interaction between the matrix and silicate layers via the formation of hydrogen bonds as shown in Figure 23. The effect of MMT content and Nylon 6 molecular weight on the tensile modulus of nanocomposites prepared using MMT modified with (HE)2M1R1 has been reported (85, 211). The addition of OMLS leads to substantial improvement in stiffness for the composites based on each of the three Nylon 6 types, e.g., LMW, MMW and HMW. Interestingly, the stiffness increases with increasing matrix molecular weight at any given

6.2 Tensile Properties The tensile modulus of a polymeric material expressing the stiffness has shown to be remarkably improved when nanocomposites are formed with layered silicates. N6CNs prepared through the intercalative ring opening polymerisation of ε-caprolactam, leading to the

32

Figure 23 Schematic illustration of the formation of hydrogen bonds in Nylon 6/MMT nanocomposite

Polymer/Layered Silicate Nanocomposites

Table 11 Mechanical properties of some Nylon 6/(HE)2M1R1 nanocomposites Modulus (GPa)

Yield Strength (MPa)

Straina (%)

Elongation at break (%) Crosshead speed (0.51 cm/min)

Izod impact strength (J/m)

0.0 wt% MMT

2.82

69.2

4.0

232

36.0

3.2 wt% MMT

3.65

78.9

3.5

12

32.3

6.4 wt% MMT

4.92

83.6

2.2

2.4

32.0

0.0 wt% MMT

2.71

70.2

4.0

269

39.3

3.1 wt% MMT

3.66

86.6

3.5

81

38.3

7.1 wt% MMT

5.61

95.2

2 .4

2.5

39.3

0.0 wt% MMT

2.75

69.7

4.0

3.4

43.9

3.2 wt% MMT

3.92

84.9

3.3

119

44.7

7.2 wt% MMT

5.70

97.6

2.6

4.1

46.2

N6/(HE)2M1R1 Nanocomposites LMW

MMW

HMW

a Strain

at yield point measured during modulus and yield strength testing using a crosshead speed of 0.51 cm/min. Reprinted from (211), T.D. Fornes et al., Polymer, 2001, 42, 9929, with permission from Elsevier Science Ltd.

concentration even though the moduli of the neat Nylon 6 types are all quite similar. In Table 11 the moduli and other mechanical properties of the virgin materials and selected (HE) 2 M 1 R 1 Nylon 6/LS nanocomposites are summarised. The slightly larger modulus of 2.82 GPa for LMW may be due to the result of a higher degree of crystallinity - the result of faster crystallisation kinetics during the cooling of the specimen during injection moulding. Figure 24 shows an Instron tensile test study of a neatPP/f-MMT (modified by alkyltrichlorosilane) composite compared to a PP/2C18-MMT ‘conventional’ composite (205). There is a sharp increase of tensile modulus for a very small clay loading (= 3 wt%) followed by a much slower increase beyond a clay loading of 4 wt%, and this is the characteristic behaviour of PLS nanocomposites. With increased clay content, the strength does not change markedly compared to the neatPP value and there is only a small decrease in the maximum strain at break. PP systems (conventionally filled, no nanometer-level dispersion, by similar fillers) do not exhibit as strong improvement in their tensile modulus. On the other hand, as the PP/LS interaction is improved as for example when MA functional groups are incorporated in the polymer, the stress is much more effectively transferred from the polymer matrix to the

inorganic filler, and thus a higher increase in tensile properties is expected. The modulus of PPCNs systematically increases with increasing clay content. The tensile strength also increases with increasing clay content up to 4 wt%, then levels off. In a recent study by Reichert and co-workers (319), a systematic study of the dependencies on compatibiliser functionality and organic modification revealed that considerable tensile properties enhancement could be achieved only when appropriate PP-MA compatibilisers are used to pretreat the OMLS in conjugation with specific organic modification of the MMTs.

6.3 Flexural Properties and Heat Distortion Temperature Sinha Ray and co-workers (54) reported the results of measurement of the flexural properties of neat PLA and various PLACNs. They conducted flexural properties measurements with injection-moulded samples according to the ASTM D-790 method. Table 12 shows the flexural modulus, flexural strength, and distortion at break of neat PLA and various PLACNs measured at 25 °C. There is a significant

33

Polymer/Layered Silicate Nanocomposites

Figure 24 Tensile characterisation of PP/f-MMT nanocomposites (■) by Instron tensile test. For comparison, conventionally filled PP/2C18-MMT “macro” composites are also shown (● ). (Reprinted from (205), E. Manias et al., Chem. Mater., 2001, 13, 3516, with permission from the American Chemical Society)

Table 12 Comparison of materials properties between neat PLA and various PLACNs prepared with trimethyl octadecylammonium modified MMT Properties

PLA

PLACN4

PLACN5

PLACN7

Bending modulus (GPa)

4.8

5.5

5.6

5.8

Bending strength (MPa)

86

134

122

105

Distortion at break (%)

1.9

3.1

2.6

2

34

Polymer/Layered Silicate Nanocomposites

increase in flexural modulus for PLACN4 compared to that of neat PLA followed by a much slower increase with increasing OMLS content, and a maximum of 21% in the case of PLACN7. On the other hand, flexural strength and distortion at break are remarkably increased with PLACN4 then gradually decrease with organoclay loading. According to the author this behaviour may be due to a high organoclay content leading to brittleness of materials.

by the formation of hydrogen bonds (see Figure 23). Although Nylon 6 in nanocomposites stabilises in a different crystal phase (γ-phase) to that found in pure Nylon 6, this different crystal phase is not responsible for the higher mechanical properties of Nylon 6/LS nanocomposites because the γ-phase is a very soft crystal phase. The increase in mechanical properties of NCH with increasing clay content is due to the mechanical reinforcement effect.

The heat distortion temperature (HDT) of a polymeric material is an index of heat resistance under applied load. Most of the PLS nanocomposites studies reported HDT as a function of clay content, characterised by ASTM D-648. Kojima and co-workers (414) showed that the HDT of pure Nylon 6 increases up to 80 °C after PLS nanocomposite preparation with MMT. In their further work (416) they reported the clay content dependence of HDT of nylon/clay hybrid (NCH). In the case of NCH there is a marked increase in HDT, from 65 °C for the neat Nylon 6 to 150 °C for 4.7 wt% nanocomposite. Beyond that wt% of MMT, the HDT of nanocomposite levels off. They also conducted HDT tests on various NCHs prepared with clay having different lengths and found that HDT also depends upon the aspect ratio of the dispersed clay particles (414).

Sinha Ray and co-workers examined the HDT of neat PLA and various PLA/LS nanocomposites (PLACNs) under different load conditions. As seen in Figure 25(a) (54), there is a marked increase of HDT with intermediate load of 0.98 MPa, from 76 °C for the neat PLA to 98 °C for PLACN4 (inorganic content = 3 wt%). The value of HDT gradually increases with increasing organoclay content, and in the case of PLACN7 (inorganic content = 5 wt%), the value increases up to 111 °C.

Because the degree of crystallinity of Nylon 6/LS nanocomposite is independent of the amount and nature of the layered silicate (clay), the HDT of Nylon 6/LS nanocomposite is due to the presence of strong interaction between the matrix and the silicate surface

On the other hand, imposed load dependence of HDT is clearly observed in the case of PLACNs. Figure 25(b) shows the typical load dependence in the case of PLACN7. The increase of HDT of neat PLA in the nanocomposite preparation is a very important property improvement, not only from the industrial point of view but also because of molecular control on the silicate layers, that is, crystallisation through interaction between PLA molecules and SiO 4 tetrahedral layers in the MMT. In the case of high load (1.81 MPa), it is very difficult to achieve high

Figure 25 (a) Organoclay (wt%) dependence of HDT of neat PLA and various PLACNs. (b) Load dependence of HDT of neat PLA and PLACN7 (Reprinted from (54), S. Sinha Ray et al., Polymer, 2003, 44, 857, with permission from Elsevier Science Ltd.)

35

Polymer/Layered Silicate Nanocomposites

HDT enhancement without strong interaction between the polymer matrix and the OMLS (MMT) (414). In the case of all PLACNs studied here, the values of the melting temperature (Tm) do not change significantly as compared to that of neat PLA. So the improvement of HDT with intermediate load (0.98 MPa) originates from the better mechanical stability of the PLACNs due to mechanical reinforcement by the dispersed clay particles, higher value of the degree of crystallinity (c) and intercalation. This is qualitatively different from the behaviour of the NCH system, where the MMT layers stabilise in a different crystalline phase (γ-phase) (416) than that found in the neat Nylon 6, with strong hydrogen bondings between the silicate layers and Nylon 6 as a result of the discrete lamellar structure on both sides of the dispersed clay particles (see Figure 23).

6.4 Thermal Stability The thermal stability of polymeric materials is usually studied by thermogravimetric analysis (TGA). Generally the incorporation of silicate in the polymer matrix enhances the thermal stability by acting as a superior insulator and mass transport barrier to the volatile products generated during decomposition. Blumstein (a.53) first reported the improved thermal stability of a PLS nanocomposite that combined PMMA and MMT. He showed that PMMA intercalated (dspacing increase of 0.76 nm) between the galleries of MMT clay resisted thermal degradation under conditions that would otherwise completely degrade pure PMMA. These PMMA nanocomposites were prepared by free radical polymerisation of MMA intercalated in the clay. TGA data reveals that both linear PMMA and crosslinked PMMA intercalated into MMT layers have a 40-50 °C higher decomposition temperature. Blumstein argues that the stability of the PMMA nanocomposite is due not only to its different structure but also to the restricted thermal motion of the PMMA in the gallery. There are lots of reports regarding the improved thermal stability of nanocomposites prepared with various types of OMLS and polymer matrices (359, a.54). Zanetti and co-workers (192) conducted detailed TG analyses of nanocomposites based on EVA. The deacylation of EVA in nanocomposites is accelerated and may occur at temperatures lower than those for the pure polymer or corresponding microcomposite due to catalysis by the strongly acid sites created by thermal decomposition of the silicate modifier. These sites are active when there is an intimate contact between the

36

polymer and the silicate. Slowing down of the volatilisation of the deacylated polymer in nitrogen may be due to the labyrinth effect of the silicate layers in the polymer matrix (169, 264, 308). In air, the nanocomposite shows a significant delay of weight loss that may derive from the barrier effect to diffusion of both the volatile thermo-oxidation products and oxygen from the gas phase to the polymer. According to Gilman and co-workers this barrier effect increases during volatilisation owing to ablative reassembly of the reticular of the silicate on the surface (a.55). Many researchers believe that the role of clay in the nanocomposite structure might be the main reason for the difference in TGA results of these systems compared to other reported systems. The dispersed clay particles act as a heat barrier, which could enhance the overall thermal stability of the system, as well as assisting in the formation of char after thermal decomposition. Thereby, in the beginning stage of thermal decomposition, the clay could shift the decomposition temperature higher. However, after that, this heat barrier effect would result in a reversed thermal stability. In other words, the stacked silicate layers could hold accumulated heat that could be used as a heat source to accelerate the decomposition process, in conjunction with the heat flow supplied by the outside heat source.

6.5 Fire Retardant Properties The Cone calorimeter is the most effective bench-scale method for studying the fire retardant properties of polymeric materials. Fire-relevant properties, measured by the Cone calorimeter, such as heat release rate (HRR), peak HRR, and smoke and CO yield, are vital to the evaluation of the fire safety of materials. Gilman reviewed the flame retardant properties of nanocomposites in detail (178, 261, 303, a.56). Table 13 shows the cone calorimeter data of three different kinds of polymer and their nanocomposites with MMT. From this table we can see that all MMTbased nanocomposites reported here show reduced flammability. Peak HRR is reduced by 50-75% for Nylon 6, PS and PP-MA nanocomposites (303). The MMT must be nano-dispersed for it to affect the flammability of the nanocomposites. The layered silicate, however, need not be completely delaminated for it to affect the flammability of the nanocomposite. In general, the nanocomposites flame retardant mechanism is that a high-performance carbonaceoussilicate char builds up on the surface during burning; this insulates the underlying material and slows the mass loss rate of decomposition products.

Polymer/Layered Silicate Nanocomposites

Table 13 Cone calorimeter data of various polymers and their nanocomposites with organoclay Sample (structure)

% residue yield (± 0.5)

Peak HRR Mean HRR (kW/m2) (kW/m2) (Δ Δ%) (Δ Δ%)

Mean Hc (MJ/Kg)

Mean SEA (m2/kg)

Mean CO yield (kg/kg)

Nylon 6

1

1010

603

27

197

0.01

N6 nanocomposite 2% (delaminated)

3

686 (32)

390 (35)

27

271

0.01

N6 nanocomposite 5% (delaminated)

6

378 (63)

304 (50)

27

296

0.02

PS

0

1120

703

29

1460

0.09

PS-silicate mix 3% (immiscible)

3

1080

715

29

1840

0.09

PS-nanocomposite 3% (intercalated/delaminated)

4

567 (48)

444 (38)

27

1730

0.08

PS/DBDPO/Sb2O3) 30%

3

491(56)

318 (54)

11

2580

0.14

PP-MA

5

1525

536

39

704

0.02

PP-MA nanocomposite 2% (intercalated/delaminated)

6

450 (70)

322 (40)

44

1028

0.02

PP-MA nanocomposite 4% (intercalated/delaminated)

12

381 (75)

275 (49)

44

968

0.02

Heat flux, 35 Kw/m2. Hc, specific heat of combustion; SEA, specific extinction area; DBDPO decabromodiphenyl oxide. Peak heat release rate, mass loss rate, and SEA data, measured at 35 kW/m2, are reproducible to within ± 10%. The carbon monoxide and heat of combustion data are reproducible to within ±15%. Reprinted from (303), J.W. Gilman et al., Chem. Mater., 2000, 12, 1866, with permission from the American Chemical Society.

6.6 Gas Barrier Properties Nanoclays are believed to increase gas barrier properties by creating a maze or ‘tortuous path’ (see Figure 26) that retards the progress of the gas molecules through the matrix resin. The direct benefit of the formation of this type of path is clearly observed in polyimide/LS nanocomposites, which show dramatically improved barrier properties with a simultaneous decrease in thermal expansion coefficient (377, 410). The O 2 gas permeability has been measured for exfoliated PLA/synthetic mica nanocomposites prepared by Sinha Ray and Yamada (9). The relative permeability coefficient value, i.e., P PLACN/P PLA where P PLACN and PPLA stand for the nanocomposite and pure PLA permeability coefficient, respectively, has been plotted as a function of the wt% of clay. The curve fitting has been achieved by using the Nielsen theoretical expression (a.57) allowing the

prediction of gas permeability as a function of the length and width of the filler particles as well as their volume fraction within the PLA-matrix (see Figure 27). In the Nielsen model, if platelets of length (≅ Lclay) and width (≅ Dclay) of the clay are dispersed parallel in the polymer matrix, then the tortuosity factor (τ) can be expressed as τ = 1+ (Lclay/2Dclay)φclay where φclay is the volume fraction of dispersed clay particles. Therefore, the relative permeability coefficient (PPLS-nano/PNeat) is given by PPLS-nano/PNeat = τ-1 = 1/[1+ (Lclay/2Dclay) φclay] where PPLS-nano and PNeat are the permeability coefficient of PLS-nano and neat polymer, respectively.

37

Polymer/Layered Silicate Nanocomposites

Figure 26 Formation of tortuous path in polymer/clay nanocomposites

Figure 27 Oxygen gas permeability of neat PLA and various PLACNs as a function of organoclay content measured at 20 °C and 90% relative humidity. The filled circles represent the experimental data. Theoretical fits based on Nielsen tortuousity model. (Reprinted from (9), S. Shinha Ray. et al., Chem. Mater., 2003, 15, 1456, with permission from the American Chemical Society)

The H 2 O-vapour permeability for PUU/LS nanocomposites is presented by Manias and coworkers in terms of P c /P o, i.e., the permeability coefficient of the nanocomposite (Pc) relative to that of the neat PUU (P o) (270). The nanocomposite formation results in a dramatic decrease in H2Ovapour transmission through the PUU sheet. The mechanism was based in the tortuosity model for aspect ratios of 300 and 1000. A comparison between the experimental values and the theoretical model prediction suggests a gradual change in the effective aspect ratio of the filler (Lclay/Dclay).

38

6.7 Ionic Conductivity Solvent-free electrolytes are of much interest because of their charge-transport mechanism and their possible applications in electrochemical devices. On this basis, Vaia and co-workers (402) have considered the preparation of polyethylene oxide (PEO)/LS nanocomposites to fine tune the ionic conductivity of PEO. An intercalated nanocomposite prepared by melt intercalation of PEO (40 wt%) into Li+-MMT (60 wt%) has been shown to enhance the stability of the ionic conductivity at lower temperatures when compared to

Polymer/Layered Silicate Nanocomposites

a more conventional PEO/LiBF 4 mixture. This improvement in conductivity is explained by the fact that PEO is not able to crystallise when intercalated, hence eliminating the presence of crystallites, which are non-conductive in nature. The higher conductivity at room temperature compared to conventional PEO/ LiBF 4 electrolytes with a single ionic conductor character makes these nanocomposites new promising electrolyte materials. The same type of behaviour in ionic conductivity is also observed in the case of polybis(methoxy-ethoxy) ethoxy phosphazene/Na+MMT nanocomposites as prepared by Hutchison and co-workers (387). Okamoto and co-workers (280) have reported a correlation between internal structure and ionic conductivity behaviour of PMMA/LS and PS/LS nanocomposites having various dispersed morphology of the clay layers by using an impedance analyser in the temperature range of 90-150 °C. The nanocomposites having finer dispersion of the clay layers, exhibit higher ionic conductivity than the other systems such as PMMA/LS nanocomposite with stacking layer structure. The activation energy of the conductivity in finer dispersed morphology systems becomes larger than the other systems and the corresponding OMLS solids.

6.8 Optical Transparency Manias and co-workers have reported the UV/visible transmission spectra of pure PVA and PVA/Na+-MMT nanocomposites with 4 and 10 wt% MMT (299). The spectra show that the visible region is not affected at all by the presence of the silicate layers and retains the high transparency of the PVA. For the UV wavelengths, there is strong scattering and/or absorption, resulting in very low transmission of the UV light.

6.9 Biodegradability Another most interesting and exciting aspect of nanocomposite technology is the significant improvements of biodegradability of biodegradable polymers after nanocomposite preparation with OMLS. There is a need for the development of ‘green polymeric materials’ that would not use toxic or noxious components in their manufacture, and could be degraded in the natural environment or easily recycled. Aliphatic polyesters are among the most promising materials for the production of environmentally friendly

biodegradable plastics. Biodegradation of aliphatic polyester is well known, in that some bacteria degrade them by producing enzymes, which attack the polymer. Tetto (338) first reported some results about the biodegradability of nanocomposites based on PCL, where the authors found that the PCL/LS nanocomposites showed improved biodegradability compared to pure PCL. According to them, the improved biodegradability of PCL after nanocomposite formation may be due to the catalytic role of the OMLS in the biodegradation mechanism. But it is still unclear how the clay increases the biodegradation rate of PCL. Sinha Ray and Okamoto (54) first reported the biodegradability of neat PLA and corresponding nanocomposites prepared with trimethyl octadecylammonium modified MMT (C3C18-MMT). Compost was prepared from food waste and tests were carried out at a temperature of 58 ± 2 °C. Figure 28 shows photographs of the recovered samples of neat PLA and PLACN4 (C3C18-MMT = 4 wt%) from compost with time. The decreased Mw and residual weight percentage (Rw) of the initial test samples with time are reported in Figure 29. The biodegradability of neat PLA is significantly enhanced after PCN preparation. Within one month, both the extent of Mw decrease and the extent of weight loss are almost at the same level for both PLA and PLACN4. After one month, however, a sharp change occurs in the weight loss of PLACN4, and within two months it is completely degraded in compost. The degradation of PLA in compost is a complex process involving four main phenomena, namely: water absorption, ester cleavage and formation of oligomer fragments, solubilisation of oligomer fragments, and finally removal of soluble oligomers by bacteria (a.58). Therefore, the factor which increases the hydrolysis tendency of PLA, ultimately controls the degradation of PLA. The presence of terminal hydroxylated edge groups on the silicate layers may be one of the factors responsible for this behaviour. In the case of PLACN4, the stacked (~ 4 layers) and intercalated silicate layers are homogeneously dispersed in the PLA matrix (as determined from TEM images). These hydroxy groups start heterogeneous hydrolysis of the PLA matrix after absorbing water from compost. This process takes some time to start. For this reason, the weight loss and degree of hydrolysis of PLA and PLACN4 is almost the same up to one month (see Figure 29). However, after one month there is a sharp weight loss in the case of PLACN4 compared to that of PLA. That means that one month is a critical time to the start of heterogeneous hydrolysis, and due to this type of hydrolysis the matrix becomes very small fragments and disappears with the

39

Polymer/Layered Silicate Nanocomposites

Figure 28 Photographic records of the biodegradability of neat PLA and PLACN4 recovered from compost with time. Initial shape of the crystallised samples was 3 x 10 x 0.1 cm3 (Reprinted from (54), S. Sinha Ray et al., Polymer, 2003, 44, 857, with permission from Elsevier Science Ltd.)

Figure 29 Time dependence of residual weight (Rw) and of matrix Mw of PLA and PLACN4 under compost at 58 ± 2 °C (Reprinted from (54), S. Sinha Ray et al., Polymer, 2003, 44, 857, with permission from Elsevier Science Ltd.)

compost. This assumption was confirmed by conducting the same type of experiment with PLACN prepared by using dimethyl dioctadecyl ammonium salt

40

modified synthetic mica which has no terminal hydroxylated edge groups: the degradation tendency was almost the same as with neat PLA (a.59).

Polymer/Layered Silicate Nanocomposites

6.10 Crystallisation 6.10.1 Spherulite Growth Crystallisation of PLS nanocomposites might be a good tool for controlling the structure of nanocomposites and thereby the various properties. Maiti and co-workers (158) have reported an example of the time variation of the diameter of the spherulite (D) for PP-MA and PP/LS nanocomposites (PPCNs) at 135 °C (see Figure 30). A linear growth of D is seen in a range of time (t) scale for PP-MA, PPCN2 and PPCN7.5. The linear growth rate G (= 1/2(dD/ dt)), defined as the initial slope of the plots, slightly increases with increasing clay content. From the extrapolation of D versus t plots, we estimated the onset time (t0), which corresponds to the induction time of the crystallisation. The t0 of both PPCNs decreases with silicate (clay) content compared to the PP-MA matrix without clay. The reduction of t0 in the PPCNs is attributed to the nature of the clay as the nucleating agent. For PPCNs, G shows almost the same value compared to PP-MA without clay. In spite of the increase in clay content, the dispersed clay particles do not have much effect on the crystallisation and there is no big acceleration of G in the

Figure 30 Spherulitic diameter as a function of crystallisation time at Tc = 130.0 °C. The arrow indicates the induction time of crystallisation for PP-MA. (Reprinted from (158), P. Maiti et al., Macromolecules, 2002, 35, 2042, with permission from the American Chemical Society)

crystallisation of the PPCNs. In the changes in t0 with crystallisation temperature (Tc), the PPCNs show remarkably short times especially at high T c , suggesting that the dispersed clay particles have some contribution to enhance the nucleation. The primary nucleation density of the spherulites, i.e., the number of heterogeneous nuclei N was given by: N = (3/4 π) (Dm/2)-3 where Dm is the maximum diameter of the spherulite, i.e., the attainable diameter before impingement. The calculated values of N at 130 °C were 4 × 10-8 for PP-MA, 50 × 10-8 for PPCN2 and 200 × 10-8 μm-3 for PPCN7.5, respectively. The time variation of the volume fraction of the spherulites increases in proportion to NG3 (≅ overall crystallisation rate). This fact suggests that the overall crystallisation rates of the PPCNs are about one or two orders of magnitude higher than that of matrix PP-MA without clay.

6.10.2 Effect of Intercalation on Enhancement of Dynamic Modulus According to Khare’s prediction (382), the confinement of polymer chains increases the viscosity and mechanical properties of the system significantly. One can expect some difference in mechanical properties with the change of the degree of intercalation in the PPCNs vis-à-vis the clay content and Tc (see Table 14). It is clear from the table that for a particular Tc, G′ increases with increasing clay content. The PP-MA crystallised at 130 °C exhibits a 9.9% increase in G′ compared to the sample crystallised at 70 °C. The PPCN7.5 and PPCN 4 show 13.3% and 30.6% increases, respectively, in the same conditions. The effect of Tc on the G′ is in the order of PP-MA < PPCN7.5 < PPCN4. It may be recalled that the Tc dependence of d(0001) showed the order of intercalation PPCN7.5 < PPCN4. This implies that much higher efficiency of the intercalation for the reinforcement is attained in the PPCN4. For PPCN2, owing to the partial exfoliation, the degree of intercalation decreases and hence the modulus decreases compared to the low Tc condition (=70 °C). Here, it should be mentioned that the crystallinity increases a little bit with increasing Tc for both PP-MA and PPCNs and the extent is almost the same for all the systems. So, it is believed that not the crystallinity but the degree of intercalation affects the storage modulus.

41

Polymer/Layered Silicate Nanocomposites

Table 14 Dynamic storage modulus of PP-MA and PPCNs at T=50 °C, crystallised at different temperatures System

Tc (°C)

G′ × 10-8 (Pa)

% increase

PP-MA

70 130

2.92 3.21

9.9

PPCN2

70 130

4.79 4.50

PPCN4

70 130

5.16 6.74

30.6

PPCN7.5

70 130

7.49 8.49

13.3

Reprinted from (158), P. Maiti et al., Macromolecules, 2002, 35, 2042, with permission from the American Chemical Society.

6.10.3 Crystallisation Controlled by Silicate Surfaces The formation of the γ-form of Nylon in the presence of clay in the Nylon 6/MMT hybride (NCH) system is well known (416). The essential difference between the γform and α-form is the molecular packing; in the αform hydrogen bondings are formed between antiparallel chains, while the molecular chains have to twist away from the zigzag planes to form the hydrogen bonds among the parallel chains in the γ-form giving rise to lesser inter-chain interaction as compared to the α-form. The lamellar morphology and distribution of clay particles in NCH (N6CN3.7) (MMT=3.7 wt%), crystallised at 170 and 210 °C, has been reported by Okamoto and Maiti (a.60) and is shown in Figure 31. The white strips (Figure 31(a)) represent the discrete lamellar pattern, and after a close look, a black clay particle inside the lamella is clearly observed. In other words, lamellar growth occurs on both sides of the clay particles, i.e., the dispersed clay particle is sandwiched by the formed lamellae. This is a unique observation of lamellar orientation on the clay layers. In the semicrystalline polymer generally stacked lamellar orientation is found. The lamellar pattern at high Tc (Figure 31(b)) is similar but along with the sandwiched structure, branched lamellae are formed which originate from the parent sandwiched lamellae. There are no clay particles found inside the branch lamellae and the γphase having irregular chain packing with distortion (γ*-phase) is formed as revealed by WAXD, this is only observed in high Tc crystallised nanocomposites. This epitaxial growth (γ*-phase) on the parent lamella forms the shish-kebab type of structure, which enhances the mechanical properties of the nanocomposites. It has

42

to be remembered that Nylon 6 has the highest capability of forming hydrogen bonding to form hydrogen-bonded sheet. Pseudohexagonal packing is favoured with hydrogen-bonding between the silicate layers and Nylon 6, as a result the induction time of N6CN3.7 becomes very short, as compared to neat Nylon 6. Once one molecular layer is nucleated on the clay surface, other molecules may form hydrogenbonds on the molecule already hydrogen-bonded to the silicate surface giving rise to the discrete lamellar structure on both sides of the clay. This unique mechanism can well explain the higher crystallisation rate of PLS nanocomposites along with the morphology and developed internal structure. This sandwich structure (each silicate layer is covered by polymer crystals) makes the system very rigid, as a result the HDT increases up to 80 °C, but the surrounding excess amorphous part (lower crystallinity of N6CN3.7 as compared to neat Nylon 6) can easily retain the polymeric properties like impact strength, which ultimately makes PLS nanocomposites an improved system.

7 Melt Rheology 7.1 Linear Viscoelastic Properties The rheological properties of in situ polymerised nanocomposites with end-tethered polymer chains were first described by Krisnamoorti and Giannelis (378). The flow behaviour of PCL- and Nylon 6-based nanocomposites differs considerably from that of the corresponding neat matrices, whereas the

Polymer/Layered Silicate Nanocomposites

(a)

100 nm

Enlarged view of one particular lamella

(b)

100 nm

Figure 31 TEM micrographs of N6CN3.7 crystallised at (a) 170 °C and (b) 210 °C. The black strip inside the white part is clay. Figure (b) shows the typical shish-kebab type of structure.

thermorheological properties of the nanocomposites were entirely determined by the behaviour of the matrices. The slope of storage modulus G′(ω) and loss modulus G′′(ω) versus the frequency aT(ω) is much smaller than 2 and 1, respectively. Values of 2 and 1 are expected for linear homodispersed polymer melts, and large deviations, especially in the presence of very small amounts of layered silicate loading, may be due to the formation of network structures in the molten state. However, such nanocomposites based on the in situ polymerisation technique exhibit fairly broad molecular mass distribution of the polymer matrix, which hides the structure relevant information and impedes the interpretation of the results.

Up to this date, the melt state linear dynamic oscillatory shear properties of various kinds of nanocomposites have been examined for a wide range of polymer matrices including: Nylon 6 with various matrix molecular weights (85), PS-PI block copolymers (133, 317), PCL (141), PP (262), PLA (54, a.48) and PBS (360, a.51, a.52). The linear dynamic viscoelastic master curves for the neat PLA and various PLACNs are shown in Figure 32 (54). The linear dynamic viscoelastic master curves were generated by applying the time-temperature superposition principle and shifted to a common temperature Tref using both frequency shift factor aT and modulus shift factor bT.

43

Polymer/Layered Silicate Nanocomposites

expressed by the power law of G′(ω) ∝ ω2 and G′′(ω) ∝ ω for neat PLA, suggesting that this is similar to the narrow Mw distribution homopolymer melts. On the other hand, for aT < 5 rad.s-1, viscoelastic response (particularly G′(ω)) for all the nanocomposites displays significantly diminished frequency dependence as compared to the matrices. In fact, for all PLACNs, G′(ω) becomes nearly independent at low aTω and exceeds the G′′(ω), characteristic of materials exhibiting a pseudo-solid like behaviour (378). The terminal zone slope values of both neat PLA and PLACNs are estimated at a lower aTω region (< 10 rad.s-1) (54). The lower slope values and the higher absolute values of the dynamic moduli indicate the formation of ‘spatially-linked’ structure in the PLACNs under the molten state. Because of this structure of highly geometric constraints, the individual stacked silicate layers are incapable of freely rotating and hence by imposing small aTω, the relaxations of the structure are prevented almost completely. This type of prevented relaxation due to the highly geometric constraints of the stacked and intercalated silicate layers leads to the presence of the pseudo-solid like behaviour as observed in PLACNs. This behaviour probably corresponds to the shear-thinning tendency, which strongly appears in the viscosity curves (aTω < 5 rad.s-1) (| η* | versus aTω). Such features strongly depended on the shear rate in the dynamic measurement because of the formation of the shear-induced alignment of the dispersed clay particles (a.61).

Figure 32 Reduced frequency dependence of storage modulus, loss modulus and complex viscosity of neat PLA and various PLACNs (Reprinted from (54), S. Sinha Ray et al., Polymer, 2003, 44, 857, with permission from Elsevier Science Ltd.)

The moduli of the PLS nanocomposites increase with increasing clay loading at all frequencies (ω). At high ωs, the qualitative behaviour of G′(ω) and G′′(ω) is essentially the same and unaffected with frequencies. However, at low frequencies G′(ω) and G′′(ω) increase monotonically with increasing clay content. In the low frequency region, the curves can be

44

The temperature dependence frequency shift factors (aT, Williams-Landel-Ferry type) used to generate master curves are shown in Figure 33. The dependence of the frequency shift factors on the silicate loading suggests that the temperaturedependent relaxation process observed in the viscoelastic measurements are somehow affected by the presence of the silicate layers (378). In the case of N6CN3.7, where the hydrogen bonding occurs on the molecule already hydrogen-bonded to the silicate surface, the system exhibits a large value of flow activation energy (estimated from the slope in Figure 33a) nearly one order higher in magnitude compared with that of neat Nylon 6. The shift factor bT shows a large deviation from a simple density effect, it would be expected that the values would not vary far from unity. One possible explanation is an internal structure development occurring in PLACNs during measurement (shear process). The alignment of the silicate layers probably supports the PCN melts to withstand the shear force, thus leading to the increase in the absolute values of G′(ω) and G′′(ω).

Polymer/Layered Silicate Nanocomposites

Figure 33 (a) Frequency shift factor aT and (b) modulus shift factor bT as a function of temperature

7.2 Elongational Flow and Strain-Induced Hardening Okamoto and co-workers (a.62) conducted an elongation test on PP/LS nanocomposites (PPCN4) under molten state at constant Hencky strain rate ( ε˙ 0 ) using elongation flow optorheometry, and they have also attempted to control the alignment of the dispersed silicate layers of intercalated PPCNs under uniaxial elongational flow. Figure 34 shows double logarithmic plots of transient elongational viscosity ηE (ε˙ 0 ; t ) against time (t) observed for a Nylon 6/LS system (N6CN3.7) and a PPCN4 (MMT=4 wt%) with different Hencky strain rates ( ε˙ 0 ) ranging from 0.001 s-1 to 1.0 s-1. The solid curve represents time development of three-fold shear

viscosity, 3η0 ( γ˙ ; t ) , at 225 °C with a constant shear rate γ˙ = 0.001 s-1. In ηE (ε˙ 0 ; t ) at any ε˙ 0 , the N6CN3.7 melt shows a weak tendency of strain-induced hardening as compared to the PPCN4 melt. A strong behaviour of strain-induced hardening for the PPCN4 melt originated from the perpendicular alignment of the silicate layers to the stretching direction as reported by Okamoto and co-workers (a.62). From TEM observations (see Figure 30), the N6CN3.7 forms a fine dispersion of the silicate layers of about 100 nm in Lclay, 3 nm thickness in dclay and ξclay of about 20-30 nm between them. The ξclay value is one order of magnitude lower than the value of Lclay, suggesting the formation of a spatially-linked structure of the dispersed clay particles in the Nylon 6 matrix. For the N6CN3.7 melt, the silicate layers are densely dispersed

45

Polymer/Layered Silicate Nanocomposites

silicate. Medellin-Rodriguez and co-workers (217) reported that molten N6CN samples showed a planar orientation of silicate layers along the flow direction, which is strongly dependent on shear time as well as clay loading, reaching a maximally orienting level after being sheared for 15 minutes with γ˙ = 60 s-1. Okamoto and co-workers carried out TEM observation of sheared N6CN3.7 with γ˙ = 0.0006 s-1 for 1000 s (a.63) (Figure 35). The edges of the silicate layers lying along the z-axis (marked with the arrow (a)) or parallel alignment of the silicate edges to the shear direction (x-axis) (marked with the arrow (b)) rather than random orientation in the Nylon 6 matrix is observed, but in fact, one cannot see these faces in this plane. Here, it should be emphasised that the planar orientation of the silicate faces along the x-z plane does not take place prominently. In the case of rapid shear flow, the commonly applicable conjecture of the planar orientation of the silicate faces along the shear direction was first demonstrated to be true by Kojima (399).

Figure 34 Time variation of elongational viscosity ηE (ε˙ 0 ; t ) for (a) N6CN3.7 melt at 225 °C and for (b) PPCN4 at 150 °C. The solid line shows three times the shear viscosity, 3ηE ( γ˙ ; t ) , taken at a low shear rate γ˙ = 0.001 s-1 on a cone-plate rheometer.

into the matrix and hence difficult to align under elongational flow. Under flow fields, the silicate layers might translationally move, but not rotationally in such a way that the loss energy becomes minimum. This tendency was also observed in a PPCN7.5 melt with a higher content of MMT (= 7.5 wt%). The orientation of silicate layers and Nylon 6 crystallites in injection moulded N6CN3.7 using WAXD and TEM has been examined (399). Kojima and co-workers found three regions of different orientations in the sample as a function of depth. Near the middle of the sample, where the shear forces are minimal, the silicate layers are oriented randomly and the Nylon 6 crystallites are perpendicular to the silicate layers. In the surface region, shear stresses are very high, so both the clay layers and the Nylon 6 crystallites are parallel to the surface. In the intermediate region, the clay layers, presumably due to their higher aspect ratio, still orient parallel to the surface and the Nylon 6 crystallites assume an orientation perpendicular to the

46

Figure 35 TEM micrograph in the x-z plane showing N6CN3.7 sheared at 225 °C with γ˙ = 0.0006 s-1 for 1000s. The x-, y- and z-axes correspond respectively to flow, shear gradient and neutral direction.

Polymer/Layered Silicate Nanocomposites

Recently, Utracki and co-workers (121) reported liquid crystal like behaviour in N6CN melts with low content of clay. They conducted a frequency sweep test and flow reversal experiment at 240 °C. According to them, one possible explanation of the increase of shear viscosity is the polycondensation of the Nylon 6 matrix during flow with rest time from 500 to 4000 s. However, this assumption was not confirmed by them.

the dispersed silicate particles act as nucleating sites for cell formation and lowering of d value with increasing silicate content. TEM observation identified biaxial flow-induced alignment of silicate particles along the cell boundary. Such aligning behaviour of silicate particles helps cells to withstand the stretching force from breaking the thin cell wall and improves the modulus of the foam.

8.2 Shear Flow Processing

8 Processing Operations

Very slow shear-processing for Nylon 6/MMT system (N6CN3.7) (MMT=3.7 wt%) was examined with an expectation that this would result in an excellent material having enhanced mechanical properties (a.63). As anticipated, N6CN3.7 subjected to shearprocessing showed strong enhancement in relative modulus as compared to the corresponding Nylon 6 matrix (Table 15). For example, after having been sheared with γ˙ = 0.0006 s-1 for 1000 s, the modulus of N6CN3.7 at 30 °C was 2.6 times higher, while for the pre-sheared N6CN3.7 the modulus was only 1.8 times higher than that of neat Nylon 6. To improve the modulus, the silicate layers seem to act as an internal bone layer to protect the materials from being bent by external forces.

Flow-induced internal structural change occurs in both shear and elongational flow, and there are differences between nanocomposites, as judged from the above results on ηE (ε˙ 0 ; t ) and 3η0 ( γ˙ ; t ) (see also Figure 34). Thus, with these rheological features of PLS nanocomposites and the characteristics of each processing operation, there are issues as to which process type should be selected for a particular nanocomposite for the enhancement of its mechanical properties. For example, the strong strain-induced hardening in ηE (ε˙ 0 ; t ) is requisite for withstanding the stretching force during processing, while the rheopexy (shear thickening) in 3η0 ( γ˙ ; t ) suggests that for such PLS nanocomposites a promising technology is processing in a confined space such as injection moulding where shear force is crucial.

8.3 Electrospinning Fibres and nanofibres of N6CN (diameter 100-500 nm) were electrospun from hexafluoro-2-propanol (HFIP) solution and collected as non-woven fabrics or as aligned yarns (125). The electrospinning process resulted in highly aligned MMT particles and Nylon 6 crystallites. The cylindrical shaped fibres and nanofibres, and ribbon shaped fibres were found in the products. Electrospinning can be expected to align other nanofillers such as carbon nanotubes (CNTs).

8.1 Foam Processing Using Supercritical CO2 Okamoto and co-workers (89) first attempted to control the alignment of dispersed silicate layers in intercalated PP/LS nanocomposites (PPCNs) during foam processing by using supercritical CO 2. The PCCN foam exhibited smaller cell size, d (≅ 28 μm) and larger cell density, N c (≅ 3.4 × 10 8cell.cm -3) compared to neat PP-MA foam (137 μm for d and 3.5 × 106cell.cm-3 for Nc, respectively), suggesting that

Table 15 Bending modulus for N6CN3.7 and neat Nylon 6 Sample Ta (°C)

Modulus of N6CN3.7 (GPa)

Modulus of Nylon 6 (GPa)

Pre-shear

Post-shear

Pre-shear

Post-shear

30

2.69

4.00

1.51

1.54

150

1.76

2.22

0.46

0.52

a

Measuring temperature.

47

Polymer/Layered Silicate Nanocomposites

8.4 Porous Ceramic Materials A new route for the preparation of porous ceramic material from thermosetting epoxy/clay nanocomposites was first reported by Brown and coworkers (312). This route offers attractive potential for diversification and application of PLS nanocomposites. Sinha Ray and Okamoto have reported on the preparation of novel porous ceramic material via burning of the PLA/LS system (PLACN) (a.49), using PLACN containing 3.0 wt.% inorganic clay. The SEM image of the fracture surface of the porous ceramic material prepared from simple burning of the PLACN in a furnace up to 950 °C is shown in Figure 36. After complete burning, as seen in the figure, the PLACN becomes a white mass with porous structure. The bright lines in the SEM image correspond to the edges of the stacked silicate layers. In the porous ceramic material, the silicate layers form a house-of-cards structure, which consists of large plates having a length of ~1000 nm and a thickness of ~30-60 nm. This implies that the further stacked platelet structure is formed during burning. The material exhibits the open-cell type structure having 100-1000 nm diameter voids, BET surface area of 31 m2 g-1 and low density of 0.187 g ml-1. The BET surface area value of MMT is 780 m2/g and that of the porous ceramic material is 31 m2/g, which suggests that about 25 MMT plates are stacked together. The estimated rough value of the compression modulus

is of the order of ~1.2 MPa, which is five orders of magnitude lower than the bulk modulus of MMT (~102 GPa) (227, 286).

9 Multifunctional Polyhedral Oligomeric Silsesquioxane Nanocomposites The use of polyhedral oligomeric silsesquioxane (POSS) nanoparticles has received a great deal of attention for the preparation of polymeric nanocomposites (119, 157, 159, 172, 173, 183, 196, 236). POSS offers a unique opportunity in this area for preparing molecularly dispersed nanocomposites. POSS molecules combine a hybrid inorganic-organic composition, R n (SiO 1.5 ) n , with nano-sized cage structures having dimensions comparable to those of most polymeric segments or coils. The incorporation of POSS into polymeric materials often results in dramatic improvements in polymer properties which include, but are not limited to, increases in use temperature, oxidation resistance, surface hardening, and improved mechanical properties as well as reductions in flammability. Therefore, many nanocomposites may be designed on the basis of using POSS with conventional polymers. Gui and co-workers

Figure 36 SEM image of porous ceramic material after coating with a platinum layer (~10 nm thickness) (Reprinted from (a.49), S. Sinha Ray et al., Nano Letts., 2002, 2, 423, with permission from the American Chemical Society)

48

Polymer/Layered Silicate Nanocomposites

(183) reported that POSS units incorporated into the epoxy network were well-dispersed in the composites, but had almost no effect on the glass transition temperature. The storage moduli of the composites above glass transition temperature were enhanced compare with that of neat epoxy resin and increased with POSS content. However, the flexural strengths were lower than that of neat resin. Zheng and co-workers (196) have described an efficient synthetic route for preparing polyolefin POSS copolymers by using a metallocene/methylaluminoxane cocatalyst system. PE-POSS and PPPOSS copolymers were obtained with a wide concentration range of POSS incorporation. The hybrids showed substantial improvement in thermooxidative stability with promise for high temperature applications.

10 Carbon Nanotube Polymer Composites Composites of carbon nanotubes (CNTs) in polymeric matrices are attractive due to their unique mechanical and electrical properties. CTN polymer nanocomposites possess high stiffness, high strength and good electrical conductivity at relatively low concentrations of CNT filler (144, a.64). These enhancements stem from the distinct properties of the CNTs themselves. Various CNTs exhibited moduli and strength levels in the range 200-1000 GPa and 200900 MPa, respectively. In addition, CNTs have a very large aspect ratio, as high as 100-1000. Such special properties make CTNs excellent candidates for high strength and electrically conductive, polymer composite applications (144). In the automotive industry, CNTs are used as a conducting agent to aid in electrostatic painting. A key problem in producing superior CNT nanocomposites is the ability to control dispersion of the CNT in polymeric matrices. For this reason, Potschke and Paul (111) have focused on the rheological behaviour of CNT/polymer composites.

polymeric materials. Since the possibility of direct melt intercalation was first demonstrated by Giannelis and co-workers (408), the melt intercalation method has become a main stream of the preparation of intercalated polymer nanocomposites without in situ intercalative polymerisation. It is a quite effective technology for the PLS nanocomposite industry. Some PLS nanocomposites are already commercially available and applied in industrial products. Biodegradable polymer-based nanocomposites seem to have a very bright future for a wide range of applications as high performance biodegradable materials. Their unique properties originating from the controlled nanostructure paves the way to a broad range of applications. Research needs to be conducted to obtain detailed rheological measurements of various PLS nanocomposites in molten states, in order to obtain information about the processing conditions of these materials. PLS nanocomposites show concurrent improvement in various material properties at very low silicate content levels and can be prepared through simple processes such as melt intercalation, directly by melt extrusion or injection moulding, opening a new dimension for plastics and composites.

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M. Alexander, P. Dubois, Mater. Sci. Eng. Res., 2000, 28, 1.

a.2

E.P. Giannelis, Organomet. Chem., 1998, 12, 675.

a.3

J.W. Gilman, Appl. Clay Sci., 1999, 15, 31.

a.4

S. Sinha Ray, K. Yamada, M. Okamoto, K. Ueda, Nano Letts., 2002, 2, 1093.

a.5

A. Blumstein, J. Polym. Sci. Part A Polym. Chem., 1965, 3, 2653.

a.6

BKG. Theng, Formation and Properties of Clay-Polymer Complexes, Elsevier, Amsterdam, 1979.

a.7

A. Okada, M. Kawasumi, A. Usuki, Y. Kojima, T. Kurauchi, O. Kamigaito, in D.W. Schaefer, J.E. Mark, Eds., Polymer Based Molecular Composites, Materials Research Society, Pittsburgh, 1990, 171, 45.

11 Outlook Development of PLS nanocomposites is one of the latest evolutionary steps in polymer technology. Nanocomposites offer attractive potential for diversification and application of conventional

49

Polymer/Layered Silicate Nanocomposites

a.8

A. Usuki, Y. Kojima, A. Okada, Y. Fukushima, T. Kurauchi, O. Kamigaito, J. Mater. Res., 1993, 8, 1174.

a.28

A. Usuki, Y. Kojima, A. Okada, Y. Fukushima, T. Kurauchi, O. Kamigaito, J. Mater. Res., 1993, 8, 1174.

a.9

S. Sinha Ray, K. Okamoto, M. Okamoto, Macromolecules, 2003, 36, 2355.

a.29

A. Okada, A. Usuki. Mater. Sci. Eng., 1995, C3, 109.

a.10

S.W. Brindly, G. Brown, Eds., Crystal Structure of Clay Minerals and Their X-ray Diffraction, Mineralogical Society, London, 1980.

a.30

J.C. Matayabas Jr, S.R. Turner, B.J. Sublett, G.W. Connell, R.B. Barbee, inventors; Eastman Chemical Co., assignee; PCT Int. Appl. WO 98/29499, 1998.

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D.J. Greenland, J. Colloid Sci., 1963, 18, 647.

a.31

a.12

A. Blumstein, J. Polym. Sci. Part A Polym. Chem., 1965, 3, 2653.

C.H. Davis, L.J. Mathias, J.W. Gilman, D.A. Schiraldi, J.R. Shields, P. Trulove, T.E. Sutto, H.C. Delong, J. Polym. Sci. Part B Polym. Phys., 2002, 40, 2661.

a.13

R.A. Vaia, R.K. Teukolsky, E.P. Giannelis, Chem. Mater., 1994, 6, 1017.

a.32

Z. Liu, D. Yan, K. Chen, Polym. Prep. America, 03, New Orleans, 2003, 44, Part 1, 1138.

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C.O. Oriakhi, I.V Farr, M.M. Lerner, Clay and Clay Minerals, 1997, 45, 194.

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A. Blumstein, S.L. Malhotra, A.C. Watterson, J. Polym. Sci. Part A Polym. Chem., 1970, 8, 1599.

M. Mitsunaga, K. Hironaka, M. Okamoto, Polym. Prep. Japan, 02, Yokohama, 2002, 51, 2645.

a.35

M. Mitsunaga, Y. Ito, M. Okamoto, S. Sinha Ray, K. Hironaka, Macromol. Mater. Eng., 2003, 288, in press.

a.36

S. Wong, S. Vasudevan, R.A. Vaia, E.P. Giannelis, D. Zax, J. Am. Chem. Soc., 1995, 117, 7568.

a.37

H.L.M. Hatharasinghe, M.V. Smalley, J. Swenson, C.D. Willians, R.K. Heenan, S.M. King, J. Phys. Chem. B, 1998, 102, 6804.

a.16

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a.18

S. Bandyopadhyay, E.P. Giallelis, Polym. Mater. Sci. Eng., 2000, 82, 208.

a.19

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a.20

Y. Sugahara, S. Satakawa, K. Kuroda, C. Kato, Clays and Clays Miner., 1988, 36, 343.

a.38

F. Bergaya, F. Kooli, Clay Miner., 1991, 26, 33.

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a.24

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R.L. Parfitt, D.J. Greenland, Clay Miner., 1970, 8, 305.

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a.26

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Polymer/Layered Silicate Nanocomposites

Materials Research Society, Warrendalel, 1998, 520, 223.

a.61

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a.47

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a.49 a.50 a.51 a.52

a.53

2C18-MMT cation modified MMT AA

acrylamide

AEA

N,N-dimethylaminoethyl acrylate

AFM

atomic force microscopy

AIBN

N,N-azobis (isobutyronitrile)

AN

acrylonitrile

S. Sinha Ray, K. Okamoto, M. Okamoto, Macromolecules, 2003, submitted.

ANI

aniline

APES

aliphatic polyester

K. Okamoto, S. Sinha Ray, M. Okamoto, J. Polym. Sci. Part B: Polym. Phys., 2003, in press.

BDMA

benzyldimethylamine

CEC

cation exchange capacity

CL

liquid ε-caprolactone

CNT

carbon nanotubes

CSA

camphorsulfonic acid

DBDPO

decabromodiphenyl oxide

DBSA

dodecylbenzenesulfonic acid

DETDA

diethyltoluene diamine

DGEBA

diglycidyl ether of bisphenol A

DMA

dynamic mechanical analysis

DMAC

N,N-dimethylacetamide

EG

ethylene glycol

EPDM

ethylene-propylene-diene terpolymer rubber

EPR

epoxy polymer resins

EVA

ethylene-vinyl acetate copolymer

FTIR

Fourier transform infrared spectroscopy

HBP

hyperbranched polymers

Hc

specific heat of combustion

HDT

heat distortion temperature

S. Sinha Ray, K. Okamoto, K. Yamada, M. Okamoto, Nano Lett., 2002, 2, 423. S. Sinha Ray, K. Okamoto, M. Okamoto, J. Nanosci. Nanotech., 2002, 2, 171.

A. Blumstein, S.L. Malhotra, A.C. Watterson, J. Polym Sci Part A Polym Chem., 1970, 8, 1599.

a.54

J.W. Gilman, Appl. Clay Sci., 1999, 15, 31.

a.55

J.W. Gilman, T. Ksahiwagi, E.P. Giannelis, E. Manias, S. Lomakin, J.D. Lichtenhan, P. Jones, S. Al-Malaika, A. Golovoy, C.A. Wilkie, Eds., Chemistry and Technology of Polymer Additives, Blackwell Science, Oxford, 1999, Chapter 14.

a.56

J.W. Gilman, Appl. Clay Sci., 1999, 15, 31.

a.57

L. Nielsen, J Macromol. Sci. Chem. A1, 1967, 5, 929.

a.58

J.W. Liu, Q. Zhao, C.X. Wan, Space Medicine and Medical Eng., 2001, 14, 308.

a.59

S. Sinha Ray, K. Yamada, M. Okamoto, K. Ueda, Macromol. Mater. Eng., 2003, 288, 203.

a.60

Abbreviations and Acronyms

P. Maiti, M. Okamoto, Macromol. Mater. Eng., 2003, 288, 440.

51

Polymer/Layered Silicate Nanocomposites

(HE)2M1R1 bis(hydroxyethyl)(methyl)-rapeseedquaternary ammonium

PLS

polymer/layered silicate

PMMA

polymethyl methacrylate

PNVC

poly(N-vinylcarbazole)

POSS

polyhedral oligomeric silsesquioxane

PP

polypropylene

PPCN

polypropylene-clay nanocomposite

PP-MA

maleic anhydride grafted polypropylene oligomer

PP-OH

polypropylene with polar telechelic OH groups

HFIP

hexafluoro-2-propanol

HHMPA

hexahydro-4-methylphthalic anhydride

HMW

high molecular weight

HRR

heat release rate

IC

isophthaloyl chloride

LCP

liquid crystalline polymer

LMW

low molecular weight

LS

layered silicates

MA

maleic anhydride

PPT

polypropylene terephthalate

MAO

methylaluminoxane

PPY

polypyrrole

MMA

methyl methacrylate

PS

polystyrene

MMT

modified montmorillonite

PU

polyurethane

MMW

medium molecular weight

PUU

polyurethane urea

MW

molecular weight

PVA

polyvinyl alcohol

N6CN

Nylon 6 matrix clay nanocomposites

PVP

poly(N-vinyl pyrrolidone)

NCH

nylon/clay hybrid

PY

pyrrole

NVC

N-vinylcarbazole

QA

quaternary ammonium

OMLS

organically modified layered silicate

Rw

residual weight

PAA

N,N-dimethylaminopropyl acrylamide

S

styrene

PANI

polyaniline

SEA

specific extinction area

PBO

polybenzoxazole

SPN

PBS

polybutylene succinate

smetic clay modified with diethylmethylammonium cation

PBSCN

PBS/MMT nanocomposites

s-PS

syndiotactic polystyrene

PBT

polybutylene terephthalate

STN

PC

polycarbonate

smetic clay modified with methyltrioctylammonium

PCL

poly(ε-caprolactone)

Tc

crystallisation temperature

PDMS

polydimethyl siloxane

TCRD

Toyota Central Research & Development Co. Inc.

PDT

polymerisation-clay delamination onset temperature

TEM

transmission electron microscope

PE

polyethylene

Tg

glass transition temperature

PEG

polyethylene glycol

TGA

thermogravimetric analysis

PEI

polyetherimide

TGAP

trifunctional triglycidyl p-amino phenol

PEO

polyethylene oxide

TGDDM

tetrafunctional tetraglycidyldiamino diphenylmethane

PET

polyethylene terephthalate

TLCP

PEVA

ethylene-vinyl alcohol copolymer

thermotropic liquid crystalline polyester

PHA

polyhydroxyamide

Tm

melting temperature

PLA

polylactide

WAXD

wide angle X-ray diffraction

PLACN

polylactide-clay nanocomposite

XRD

X-ray diffraction

52

References and Abstracts

Abstracts from the Polymer Library Database Item 1 Macromolecular Materials and Engineering 288, No.2, 20th Feb.2003, p.175-80 ALIGNED NAFION NANOCOMPOSITES: PREPARATION AND MORPHOLOGICAL CHARACTERIZATION Karthikeyan C S; Schossig M; Radovanovic E; Goncalves M C; Wittich H; Schulte K; Nunes S P GKSS-Research Centre; Campinas,Universidade; Polymer Composites A nanocomposite based on Nafion (ionomer) and a layered silicate (montmorillonite) was prepared and processed under an electric field to induce orientation of the inorganic filler. The morphology of the oriented composites was analysed by scanning electric potential microscopy(SEPM) and TEM. Films based on both plain ionomer and composite exhibited fine contrast in SEPM, differentiating the phases, which could not be achieved using conventional atomic force microscopy. The orientation of the silicates in the composites was evident from the SEPM picture. 20 refs. BRAZIL; EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.887708 Item 2 Journal of Polymer Science: Polymer Chemistry Edition 41, No.7, 1st April 2003, p.905-13 PREPARATION, CHARACTERIZATION, AND PROPERTIES OF NOVOLAC-TYPE PHENOLIC/ SIO2 HYBRID ORGANIC-INORGANIC NANOCOMPOSITE MATERIALS BY SOL-GEL METHOD Chin-Lung Chiang; Ma C C M; Dai-Lin Wu; HsuChiang Kuan Taiwan,National Tsing Hua University; HungKuang,University Novolac-type phenolic resin/silica hybrid organicinorganic nanocomposites were prepared by a sol-gel process. FTIR and NMR were used to identify the structure of modified hybrid nanocomposites. The silica network was characterised by silicon-29 NMR. Results obtained indicated that Q4 (tetrasubstituted) and T3 (trisubstituted) were the main microstructures. The size of silica in the phenolic resin was characterised by SEM. The particle size of inorganic silica in the modified system was less than 100 nm. The nanocomposites exhibited good transparency and their thermal properties and mechanical properties exhibited significant improvement. The materials showed good flame-retardant properties. 33 refs. TAIWAN

Accession no.887627

© Copyright 2003 Rapra Technology Limited

Item 3 Journal of Polymer Science: Polymer Physics Edition 41, No.7, 1st April 2003, p.670-8 NANOCOMPOSITES BY MELT INTERCALATION BASED ON POLYCAPROLACTONE AND ORGANOCLAY Yingwei Di; Iannace S; de Maio E; Nicolais L Napoli,Universita Federico II; Naples,Institute of Composite Materials & Biomaterials Nanocomposites based on biodegradable polycaprolactone(PCL) and organically-modified layered silicates (montmorillonites) were prepared by melt mixing. The dependence of organoclay intercalation and/or exfoliation on the processing conditions and type of organoclay was studied, together with the thermal and rheological behaviour of the resultant nanocomposites. The nanocomposites with exfoliated filler exhibited improved thermal stability because the exfoliated platelets retarded the diffusion of oxygen into the polymer matrix. Much more significant shear thinning behaviour was observed for nanocomposites than for the neat PCL melt. The storage modulus and loss modulus exhibited less frequency dependence than pure PCL at a low frequency range. These results were attributed to the strong interactions of PCL and exfoliated organoclay layers, which lowered the molecular mobility of PCL and the resultant exfoliation structure of the organoclay. 29 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; ITALY; WESTERN EUROPE

Accession no.887546 Item 4 European Polymer Journal 39, No.5, May 2003, p.945-50 POLYPROPYLENE-CLAY NANOCOMPOSITES: EFFECT OF COMPATIBILIZING AGENTS ON CLAY DISPERSION Garcia-Lopez D; Picazo O; Merino J C; Pastor J M Valladolid,Universidad; CIDAUT PP-clay nanocomposites were prepared and studied using two different coupling agents, diethyl maleate and maleic anhydride. Two different clays, a commercial montmorillonite (Nanomer I30.TC) and a sodium bentonite purified and modified with octadecylammonium ions, were also used. The relative effect of each factor, matrix and clay modification, could be observed from structural analysis (small-angle X-ray scattering and TEM) and mechanical property tests. An explanation of the results was proposed in terms of the microstructure and chemical nature of the systems and the thermodynamic interaction operating during nanocomposite preparation. 17 refs.

53

References and Abstracts

NANOCOR EUROPEAN COMMUNITY; EUROPEAN UNION; SPAIN; WESTERN EUROPE

Accession no.887463 Item 5 European Coatings Journal 4, No.3, 2003, p.138/42 TINY PARTICLES, HUGE EFFECT. RADIATION CURABLE SILICA NANOCOMPOSITES FOR SCRATCH AND ABRASION RESISTANT COATINGS Roscher C hanse chemie AG Nanotechnological reinforced composites consisting of monodisperse, non-agglomerated silica-particles and radiation-curing acrylic resins (polyether acrylates, polyester acrylates and epoxy acrylates) were found to exhibit a significant enhancement of scratch and abrasion resistance and hardness without possessing the disadvantages known from other inorganic additives. Even with loadings of silica up to 50%, water-clear products with low viscosities and no sediment formation were obtained, rendering these nanocomposites useful for use in all types of high performance applications. 8 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.887402 Item 6 Journal of Polymer Science: Polymer Physics Edition 41, No.10, 15th May 2003, p.1014-21 POLY(1-BUTENE)/CLAY NANOCOMPOSITES: PREPARATION AND PROPERTIES Wanjale S D; Jog J P Pune,National Chemical Laboratory Poly(1-butene)(PB)/clay nanocomposites were successfully prepared using the melt-intercalation process with organically modified clay. X-ray diffraction patterns confirmed the intercalation of polymer in the silicate layers. Thermal analysis (DSC) was used to show the effect of clay on the phase transformation of PB. DMA showed that the nanocomposites had higher storage moduli relative to pure PB, dependent on the clay content, while the coefficient of thermal expansion was found to be significantly lower. 37 refs. INDIA

Accession no.887350 Item 7 Polymer 44, No.9, 2003, p.2761-72 POLYAMIDE-12 LAYERED SILCATE NANOCOMPOSITES BY MELT BLENDING McNally T; Murphy W R; Chun Y Lew; Turner R J; Brennan G P

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Belfast,Queen’s University Nanocomposites were prepared form polyamide-12 and either tetrasilicic fluoromica (ME100) or quaternary tallow ammonium chloride modified fluoromica (MAE) by melt blending. The structure of the materials were characterised by wide angle X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis, transmission electron microscopy and atomic force microscopy. The ME100 nanocomposites exhibited a largely intercalated morphology, while the MAE nanocomposites were highly exfoliated. The polymer crystallites lay perpendicular to the clay surfaces. The mechanical properties of the nanocomposites were much improved over polyamide-12, with only 4% of MAE in particular producing significant enhancement of the tensile and flexural properties and an increase in elongation at break from 120% to 500%. However, the impact strength was significantly reduced. Considerable increases in temperature were observed during tensile testing, in some cases causing the temperature to rise above the glass transition. The deformation mechanism was dominated by microvoid formation. The shear viscosity of the nanocomposites was lower than polyamide-12, in particular when MAE was used. This was shown not to be the result of polymer degradation. The thermal properties of the nanocomposites were investigated by thermomechanical analysis, thermogravimetric analysis and differential scanning calorimetry. The melting and crystallisation temperatures were identical to those of the pure polymer, and the thermal stability was slightly increased in the MAE case. The coefficient of thermal expansion increased slightly in the ME100 composite, but fell by 16% for the MAE material. The glass transition temperature and dynamic storage modulus of the materials were increased over polyamide-12. 53 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.886563 Item 8 Polymer Preprints Volume 43. Number 2. Fall 2002. Papers presented at the ACS meeting held Boston, Ma., 18th-22nd Aug.2002. Washington. DC, ACS,Div.of Polymer Chemistry, 2002, p.1049-50, 28cm, 012 MORPHOLOGY-RHEOLOGY-CORRELATIONS FOR POLYSTYRENE/LAYERED-SILICATE NANOCOMPOSITES Yuanming Zhang; Jin Zhu; Verploegen E A; Giannelis E P; Wiesner U Cornell University (ACS,Div.of Polymer Chemistry) Nanocomposites were prepared from polystyrene (PS) and organically modified montmorillonite with three different morphologies: immiscible, intercalated, and delaminated. The specific morphologies were confirmed by wide angle

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References and Abstracts

X-ray diffraction and transmission electron microscopy. The linear viscoelastic properties of the composites was investigated. Non-terminal rheological responses with higher storage moduli than PS were observed in all cases. As the morphology changed from immiscible to intercalated to delaminated, the viscoelastic behaviour changed from predominantly viscous behaviour to elastic behaviour exhibiting an elastic plateau. As frequency increased, the behaviour of the three nanocomposites became increasingly similar to one another and to PS. 5 refs. USA

Accession no.886522 Item 9 Chemistry of Materials 15, No.7, 8th April 2003, p.1456-65 NEW POLYLACTIDE/LAYERED SILICATE NANOCOMPOSITES. 3. HIGH-PERFORMANCE BIODEGRADABLE MATERIALS Ray S S; Yamada K; Okamoto M; Ogami A; Ueda K Toyota Technological institute; Unitika Ltd. The preparation, characterisation and properties of new biodegradable polylactide/organically modified synthetic fluorine mica nanocomposites with either intercalated, exfoliated or mixed intercalated/exfoliated silicate layers are reported. The structure, thermal properties, crystallite morphology, dynamic mechanical properties, flexural properties and heat distortion temperature are discussed as are their oxygen permeability and biodegradability. 47 refs. JAPAN

Accession no.886472 Item 10 Polymer Preprints. Volume 43. Number 2. Fall 2002. Papers presented at the ACS Meeting held Boston, Ma., 18th-22nd Aug.2002. Washington, DC, ACS,Div.of Polymer Chemistry, 2002, p.1314-5, 28cm, 012 POLYSTYRENE NANOCOMPOSITE USING A MASTERBATCH PREPARED BY POLYMERIZATION IN CLAY-DISPERSED WATER Ko M B; Jeong J; Jho J Y; Yang K Seoul,National University; LG Chemicals Ltd. (ACS,Div.of Polymer Chemistry) Clay/PS nanocomposites were prepared by emulsion polymerisation in clay-dispersed water using a functional comonomer, 2-aminoethyl methacrylate hydrochloride, to coagulate the emulsion particles and the polymerisation, coagulation behaviour and final dispersion state of the nanocomposites were examined. It was found that incorporation of the monomer appeared to promote the coagulation of the emulsion particles. Melt-blending a masterbatch of the clay-dispersed composite prepared by copolymerising the comonomer with styrene provided

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nanocomposites having individual silicate layers well distributed in the PS matrix. 12 refs. KOREA; USA

Accession no.886429 Item 11 Polymer Preprints. Volume 43. Number 2. Fall 2002. Papers presented at the ACS Meeting held Boston, Ma., 18th-22nd Aug.2002. Washington, DC, ACS,Div.of Polymer Chemistry, 2002, p.1312-3, 28cm, 012 POLYMER-LAYERED SILICATE NANOCOMPOSITES BY SUSPENSION AND EMULSION POLYMERIZATIONS: PVC-MMT NANOCOMPOSITES Xu Y; Malaba D; Huang X; Aguilar-Solis C; Brittain W J Akron,University (ACS,Div.of Polymer Chemistry) Polyvinyl chloride-montmorillonite nanocomposites were prepared either by in-situ suspension polymerisation using initiator- and comonomer-modified montmorillonite in the presence of free-radical initiators, such as AIBN, and compared. It was found that monomer conversion was low when the nanocomposites were prepared using initiatormodified montmorillonite. Exfoliated nanocomposites were obtained in the presence of both the initiator- and comonomer-modified montmorillonite. 5 refs. USA

Accession no.886428 Item 12 Polymer Preprints. Volume 43. Number 2. Fall 2002. Papers presented at the ACS Meeting held Boston, Ma., 18th-22nd Aug.2002. Washington, DC, ACS,Div.of Polymer Chemistry, 2002, p.1281-2, 28cm, 012 PREPARATION OF POLYMER-CLAY NANOCOMPOSITES, AND THEIR STUDIES BY MULTINUCLEAR SOLID-STATE NMR Hou S-S; Bonagamba T J; Beyer F L; Schmidt-Rohr K Iowa State University; US,Army Research Laboratory (ACS,Div.of Polymer Chemistry) Nanocomposites were prepared from Na+-hectorite and Na+-montmorillonite and either styrene-ethylene oxide diblock copolymers or PS latex. The microstructure, molecular motion and molecular conformation of these nanocomposites were investigated using Silicon 29 NMR spectroscopy with high sensitivity Silicon 29 detection, proton-Silicon 29 HETCOR NMR spectroscopy with proton spin diffusion and proton-Carbon 13 correlation NMR spectrocopy with proton spin diffusion. The data obtained indicated that these NMR techniques could be performed on the above composites with very good sensitivity and selectivity. 10 refs. USA

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References and Abstracts

Item 13 Fire & Materials 27, No.1, Jan.-Feb.2003, p.1-7 SOME COMMENTS ON THE MODES OF ACTION OF NANOCOMPOSITES IN THE FLAME RETARDANCY OF POLYMERS Lewin M Brooklyn,Polytechnic University; Jerusalem,Hebrew University A study was carried to account for the formation of a montmorillonite-rich char surface upon pyrolysis and combustion of montmorillonite-containing nanocomposites. The role of surface free energy in the surface structure of polymer blends, especially those with a silicon-containing component, was examined and data from an X-ray photoelectron spectroscopic study of the accumulation of montmorillonite on the surface of a PS nanocomposite re-examined. It is suggested that the accumulation of montmorillonite is due to migration or convection of montmorillonite to the surface of the nanocomposite mainly as a result of the lower surface energy of montmorillonite. 12 refs. ISRAEL; USA

Accession no.886406 Item 14 Journal of Applied Polymer Science 88, No.6, 9th May 2003, p.1526-35 MECHANICAL AND RHEOLOGICAL PROPERTIES OF THE MALEATED POLYPROPYLENE-LAYERED SILICATE NANOCOMPOSITES WITH DIFFERENT MORPHOLOGY Chong Min Koo; Mi Jung Kim; Min Ho Choi; Sang Ouk Kim; In Jae Chung Korea,Advanced Institute of Science & Technology; Cornell University; Wisconsin-Madison,University Three types of maleated PP-layered silicate nanocomposites (deintercalated, intercalated and exfoliated) were prepared from two types of maleated PP with different molecular weights, layered with pristine montmorillonite or organically modified montmorillonite. The molecular weight difference of the maleated PP matrix affected the intercalation kinetics and the final morphology of the nanocomposites. The rheological and mechanical properties depended largely on the final morphology of the nanocomposite and the clay content. 42 refs. KOREA; USA

Accession no.886169 Item 15 GPEC 2003: Plastics Impact on the Environment. Proceedings of a conference held Detroit, 26th-27th Feb.2003. Brookfield, CT, SPE, 2003, p.69-78, 27cm, 012

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EMERGING GREEN NANOCOMPOSITES: STRIVING FOR SUSTAINABILITY IN AUTOMOTIVE APPLICATIONS Mohanty A K; Misra M; Drzal L T Michigan,State University (SPE,Environmental Div.) Automakers now see strong promise in polymer clay nanocomposites, especially in PP/TPO/nylon based nanocomposites. Nanocomposites are lighter than metals and filled composites, thus main motivation for large fuel and energy savings in transportation. There is a growing urgency to develop novel biobased products and innovative technologies than can reduce the US dependence on fossil fuel. Green/biobased nanocomposites are the next generation of materials for the future. Renewable resource-based biodegradable polymers, including cellulosic plastic, polylactic acid and polyhydroxyalkanoate, are some of the potential biopolymers which on effective reinforcement with nanoclay can generate so called “green” nanocomposites for automotive applications. Such newly developing green nanocomposites need to be “sustainable” to compete with existing petroleum-based polymer clay nanocomposites. Green nanocomposites derived from renewable resources, having recycling capability and triggered biodegradability, with commercial viability and environmental acceptability, are termed as “sustainable”. 25 refs. USA

Accession no.886062 Item 16 Polymer 44, No.8, 2003, p.2441-6 EFFECT OF SAMPLE THICKNESS ON THE MECHANICAL PROPERTIES OF INJECTIONMOLDED POLYAMIDE-6 AND POLYAMIDE-6 CLAY NANOCOMPOSITES Uribe-Arocha P; Mehler C; Puskas J E; Altstadt V Bayreuth,University; BASF AG; Western Ontario,University Dynamic mechanical analysis in the injection direction under torsion and tension, and tensile testing, were used to examine the effects of sample thickness, ranging from 0.5 to 2mm thickness, on the mechanical properties polyamide 6 (PA6), and nanocomposites of PA6 and clay. Scanning electron microscopy was used to examine fracture surfaces, and evidence of a skin-core effect was observed in samples of the nanocomposite but not in the homopolymer. A micromechanical model was proposed, involving multiple voiding in the core with a stiffer and oriented skin, to explain the failure mechanism and the clear effect of reduction in tensile modulus and yield stress with increasing sample thickness. 32 refs. CANADA; EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.885788

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References and Abstracts

Item 17 Polymer 44, No.8, 2003, p2271-9 VAPOR BARRIER PROPERTIES OF POLYCAPROLACTONE MONTMORILLONITE NANOCOMPOSITES: EFFECT OF CLAY DISPERSION Gorrasi G; Tortora M; Vittoria V; Pollet E; Lepoittevin B; Alexandre M; Dubois P Salerno,University; Mons Hainaut,University Nanocomposite films of polycaprolactone (PCL) containing different levels of montmorillonite were prepared by melt blending of sodium montmorillonite to give microphase composites, and by ring opening polymerisation of e-caprolactone in the presence of organo modified montmorillonite to give exfoliated composites. Intercalated composites were prepared similarly, but the ring opening polymerisation was carried out in the presence of sodium montmorillonite, and the blending method utilised organo modified montmorillonite. Barrier properties to water vapour, and to dichloromethane, were studied by determining sorption and zero concentration diffusion coefficients for each liquid. Water sorption increased with increasing montmorillonite content, but diffusion parameters of microphase and intercalated nanocomposites were similar to pure PCL. For exfoliated nanocomposites, much lower diffusion parameters were observed. Sorption of the dichloromethane depended on amorphous PCL content at low relative pressures, but at higher relative pressures an enormous increase in sorption was observed due to plasticisation of the polymer matrix. Diffusion coefficient for both intercalated and exfoliated nanocomposites was lower than microphase composite due to higher obstruction to penetrant molecules in these nanocomposites. 24 refs. BELGIUM; EUROPEAN COMMUNITY; EUROPEAN UNION; ITALY; WESTERN EUROPE

Accession no.885768 Item 18 Polymer Preprints. Volume 43. Number 2. Fall 2002. Papers presented at the ACS meeting held Boston, Ma., 18th-22nd Aug.2002. Washington, DC, ACS,Div.of Polymer Chemistry, 2002, p.1019-20, 28cm, 012 PVC NANOCOMPOSITES VIA EMULSION AND SUSPENSION POLYMERIZATION Aguilar-Solis C; Yijin Xu; Brittain W J Akron,University (ACS,Div.of Polymer Chemistry) Both emulsion and suspension polymerisation were used to prepare polyvinyl chloride in the presence of untreated and organically modified clays to produce nanocomposites. Clay in the nanocomposites was exfoliated, and the mechanisms of nanocomposite synthesis were discussed. X-ray diffraction and

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thermogravimetric analysis were used in characterisation of the composites. 8 refs. USA

Accession no.885691 Item 19 Polymer Testing 22, No.4, 2003, p.453-61 EFFECT OF DIFFERENT CLAY TREATMENT ON MORPHOLOGY AND MECHANICAL PROPERTIES OF PVC-CLAY NANOCOMPOSITES Chaoying Ean; Xiuying Qiao; Yong Zhang; Yinxi Zhang Shanghai,Jiao Tong University Partially intercalated and disordered PVC/sodium montmorillonite (MMT) nanocomposites, and partially intercalated and partially exfoliated PVC/organically modified MMT nanocomposites were prepared by a melt blending process. The nanocomposites were examined by wide-angle X-ray diffraction, transmission electron microscopy and dynamic mechanical thermal analysis. At MMT loadings of up to 3 weight percent, stiffness and impact strength of the nanocomposites showed an improvement over that of PVC. Below 5 weight percent MMT, the nanocomposites retain good optical clarity. The content of organically modified MMT should be kept below 5 weight percent to improve mechanical properties and processing stability of the nanocomposites. 20 refs. CHINA

Accession no.885423 Item 20 Flexible No.6, March-April 2003, p.6/14 SMALL BEGINNINGS Anyadike N Polymer compounds containing relatively low loadings of nanometre-sized mineral particles are beginning to show up in PP, barrier beer bottles and nylon packaging films. The present generation of nanocomposite materials already show remarkable characteristics, including improved thermal stability, significantly increased mechanical strength and considerably improved barrier properties, and are increasingly seen as a solution for high-barrier packaging. It is in the production of films with barrier properties that the nanocomposite technology is finding the most application. Nylon 6 nanocomposites find application in mono and multilayer films as well as thin-wall structures. Recent data indicates the significant extent to which nanoclay incorporation can reduce the extent of water absorption in a polymer. Nanotechnology also enhances UV and infrared radiation absorbance, making it particularly suitable for blister packaging for pharmaceuticals. WORLD

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Item 21 Polymer Engineering and Science 43, No.3, March 2003, p.661-9 SYNTHESIS AND MECHANICAL PROPERTIES OF UNSATURATED POLYESTER BASED NANOCOMPOSITES Inceoglu A B; Yilmazer U Ankara,Middle East Technical University Two classes of nanocomposites are synthesised using an unsaturated polyester resin as the matrix and sodium montmorillonite as well as an organically modified montmorillonite as reinforcing agents. X-ray diffraction pattern of the composites shows that the interlayer spacing of the modified montmorillonite expands from 1.25 to 4.5 nm, indicating intercalation. Glass transition values of these composites increase from 72 deg.C, in the unfilled unsaturated polyester, to 86 deg.C in the composite with 10% organically modified montmorillonite. From scanning electron microscopy, it is seen that the degree of intercalation/exfoliation of the modified montmorillonite is higher than in the unmodified one. The mechanical properties also support these findings, since in general, the tensile modulus, tensile strength, flexural modulus, flexural strength and impact strength of the composites with modified montmorillonite are higher than the corresponding properties of the composites with unmodified montmorillonite. Tensile modulus, tensile strength, flexural modulus and flexural strength values show a maximum, whereas the impact strength exhibits a minimum at approximately 3-5 wt.% modified montmorillonite content. These results imply that the level of exfoliation may also exhibit a maximum with respect to the modified montimorillonite content. The level of improvement in the mechanical properties is substantial. Adding only 3 wt.% organically modified clay improves the flexural modulus of unsaturated polyester by 35%. The tensile modulus of unsaturated polyester is also improved by 17% at 5 wt.% of organically modified clay loading. 9 refs. TURKEY

Accession no.884499 Item 22 Nanocomposites 2003. Proceedings of a conference held Amsterdam, 13th-14th Feb.2003. Peterborough, Emap Maclaren. Polymer Group, 2003, Paper 6, pp.27, 31cm, 012 PRODUCING NANOCOMPOSITES USING COMPOUNDING EXTRUDERS Schonfeld S Coperion Werner & Pfleiderer GmbH & Co.KG Nanocomposites present significant potential for development of a wide range of enhanced performance polymer compounds. Even a small loading (4-5%) of properly dispersed clay in the base polymer can yield substantial improvement in thermal properties such as HDT, and mechanical properties such as flexural strength

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and modulus (without significant loss of impact, barrier properties, flame resistance, and abrasion resistance). Until recently, most development has been focused on determining proper surface treatment to make the clay compatible with the base polymer and therefore improve the ease with which it can be dispersed in the polymer. Most publications still concentrate on the importance of the chemistry used to modify the surface of the clay and give a description of resultant product properties but do not include the role of processing or give details of the compounding set-up. The key challenge is therefore to determine how to maximise clay exfoliation. Of course, using clay modified specifically for compatibility with the polymer matrix is extremely important, but proper design and operation of the compounding system is equally critical. Different extruder systems available are discussed with regard to their design flexibility for the processing of nanocomposites. Results of recent experiments on the co-rotating twin screw extruder (Werner & Pffleiderer ZSK) and the reciprocating single screw system (Buss Kneader MKS) and the key unit operations necessary to obtain clay that is well dispersed are presented. It is demonstrated how the results from the laboratory tests can be transferred for the design of a production line. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.884433 Item 23 Journal of Materials Science Letters 22, No.1, 1st Jan.2003, p.53-5 FABRICATION AND VISCOELASTIC PROPERTIES OF BIOGRADABLE POLYMER/ ORGANOPHILIC CLAY NANOCOMPOSITES Lee C H; Lim S T; Hyun Y H; Choi H J; Jhon M S Inha,University; Carnegie-Mellon University Compared to conventional polymer blends in which the internal structure of the clay is retained without intercalation of polymer, polymer/clay nanocomposites are a new class of composites that show the characteristic incorporation on the order of nanometer (nm) range inbetween the consisting components. As a result they usually exhibit physical and mechanical properties superior to those of conventional composites such as increased moduli and strengths, high heat distortion temperatures, electrical conductivity, anticorrosion and electrorheological properties due to a unique morphology and improved interfacial properties. There are two types of internal structures: intercalation, in which extended polymer chains are inserted between clay layers, and exfoliation, in which the clay single layers are dispersed into a continuous polymer matrix. The synthesis and rheological properties of nanocomposites fabricated from a biodegradable polymer and organophilic montimorillonite are investigated. Even though BAP can compete with PHB in cost, applications of BAP are limited

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References and Abstracts

material showed half the water absorption of PA6. The dynamic mechanical properties of the system were investigated, showing that PA6CN has a higher storage modulus than PA6 at all temperatures and that the relaxation peaks appear at the same temperatures as in PA6. 27 refs.

because it is still expensive when compared to conventional polymers. Therefore, BAP/clay nanocomposites can lower cost and increase the range of applicability of biodegradable polymers. Recently, biodegradable polymers have been used to produce poly(llactide) (PLLA)-montmorillonite (MMT), poly(Ecaprolactone) (PCL)-MMT and BAP intercalated nanocomposites. 31 refs.

CHINA; EUROPEAN UNION; SCANDINAVIA; SWEDEN; WESTERN EUROPE

KOREA; USA

Accession no.884030

Accession no.884417 Item 24 Revista de Plasticos Modernos 83, No.550, April 2002, p.403-8 Spanish POLYMERIC NANOCOMPOSITES. II. Lopez M A; Arroyo M Instituto de Ciencia y Tecnologia de Polimeros A review is made of methods used in the preparation of nanocomposites consisting of silicate fillers dispersed in polymer matrices. The mechanical, dynamic mechanical, thermal, optical and barrier properties of such composites are considered, and the influence of the nature and content of the filler on these properties is examined. 58 refs. (Part I: Ibid., 83, No.549, March 2002, p.290-5). EUROPEAN COMMUNITY; EUROPEAN UNION; SPAIN; WESTERN EUROPE

Accession no.884066 Item 25 Journal of Applied Polymer Science 88, No.4, 25th April 2003, p.953-8 POLYAMIDE 6/CLAY NANOCOMPOSITES USING A COINTERCALATION ORGANOPHILIC CLAY VIA MELT COMPOUNDING XiaoHai Liu; Qiuju Wu; Berglund L A; Lindberg H; Jiaqi Fan; Zongneng Qi Lulea,University of Technology; Chinese Academy of Sciences Polyamide 6/clay nanocomposites (PA6CN) were prepared via a melt compounding method using a new type of organophilic clay. The novel filler was produced by cointercalation of a bisphenol A diglycidyl ether epoxy resin and hexadecyltrimethylammonium bromide into sodium montmorillonite. The material was characterised by X-ray diffraction and transition electron microscopy, and it was found that the silicate layers were dispersed homogeneously through the matrix in an almost fully exfoliated manner. This behaviour was ascribed to strong interactions between the epoxy groups and amide end groups of the polymer. The heat distortion temperature and impact strength were much improved over PA6. The notched Izod impact strength of PA6Cn was 80% higher than that of PA6 at 5% clay loading and was still higher than that of PA6 at 10% clay loading. The 10% clay loaded

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Item 26 Polymer Bulletin 49, No.6, March 2003, p.473-80 THERMALLY-CURED AND E-BEAM-CURED EPOXY LAYERED-SILICATE NANOCOMPOSITES Chenggang Chen; Curliss D Dayton,University; Wright-Patterson Air Force Base Layered-silicate epoxy nanocomposites were cured by conventional thermal processing. Wide angle X-ray diffraction, small angle X-ray scattering and TEM indicated that the nanocomposites had an exfoliated nanostructure. Layered-silicate epoxy nanocomposites cured by electron beam curing showed an intercalated nanostructure. Dynamic mechanical analysis showed an improvement in the modulus without decreasing the glass transition temperature for the electron beam cured nanocomposites. 16 refs. USA

Accession no.883989 Item 27 Polymer Preprints. Volume 43. Number 2. Fall 2002. Papers presented at the ACS Meeting held Boston, Ma., 18th-22nd Aug.2002. Washington, D.C., ACS,Div.of Polymer Chemistry, 2002, p.900-1, 28cm, 012 INTERACTIONS OF WATER SOLUBLE POLYMERS WITH MONTMORILLONITE CLAY FOR BIODEGRADABLE NANOCOMPOSITE APPLICATIONS Haynes, C T; Lochhead R Y Southern Mississippi,University (ACS,Div.of Polymer Chemistry) Poly(N-vinyl formamide), poly(vinyl amine) and poly(vinyl amine) which was hydrophobically modifed by reacting with methoxybenzoic acid chloride were prepared. The interactions between the polymer/ montmorillonite systems at various pHs were studied. Poly(N-vinyl formamide) adsorbed preferentially to the clay edges at both pH 3.0 and 7.0, but the method of polymer interaction could not be determined by the FTIR spectroscopic methods used. the charge density on the backbone of this non-ionic polymer was unaffected by the pH of the system. No polymer adsorption was observed at pH 10.0. Poly(vinyl amine) was adsorbed preferentially to the alumina-hydroxyl clay edges at pH

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References and Abstracts

3.0 and to the silica clay faces at pH 7.). At pH 10.0, the negative charges on both the clay face and edges inhibited interaction with the amine groups and no adsorption was observed. Hydrophobically modifed poly(vinyl amine) adsorbed most readily on the silica clay faces, regardless of the pH of the system. 4 refs.

THE RELATIONSHIP BETWEEN NANO- AND MICRO-STRUCTURES AND MECHANICAL PROPERTIES IN PMMA-EPOXY-NANOCLAY COMPOSITES Park J H; Jana S C Akron,University

USA

Organically modified nanoclay particles were dispersed in PMMA with the aid of mixtures of aromatic and aliphatic epoxy resins and the mechanical properties of the resulting three-phase composite materials determined by means of tensile and impact testing. The state of clay particle dispersion was analysed by one-dimensional wide angle X-ray diffraction, TEM and scanning electron microscopy and the mechanical properties of the composites compared with those for PMMA-nanoclay, epoxy-nanoclay and PMMA-epoxy composites as a function of nano- and micro-dispersed domains of phase separated epoxy resin and nanoparticles. 33 refs.

Accession no.883979 Item 28 Polymer 44, No.4, 2003, p.1315-9 MECHANICAL PROPERTIES OF INTERCALATED CYANATE ESTER-LAYERED SILICATE NANOCOMPOSITES Ganguli S; Dean D; Jordan K; Price G; Vaia R Tuskegee,University; Raytheon Electronic Systems Co.; Dayton,University; Wright-Patterson Air Force BAse Cyanate ester/organically modified layered silicate (OLS) nanocomposites were synthesised. the thermal stability, glass transition temperature and coefficient of thermal expansion were improved for a 2.5% loading of OLS. The fracture toughness and flexural modulus increased by 30% as the OLS loadings increased to 5%. 12 refs. USA

Accession no.883742 Item 29 Polymer Preprints, Volume 43. Number 2. Fall 2002. Papers presented at the ACS Meeting held Boston, Ma., 18th-22nd Aug. 2002. Washington, DC, ACS,Div. of Polymer Chemistry, 2002, p.900-1, 28 cm, 012 INTERACTIONS OF MODEL WATER SOLUBLE POLYMERS WITH MONTMORILLONITE CLAY FOR BIODEGRADABLE NANOCOMPOSITE APPLICATIONS Haynes C T; Lochhead R Y Southern Mississippi,University (ACS,Div.of Polymer Chemistry) An investigation was carried out into the adsorption of water-soluble polymers (polyvinyl formamide, polyvinyl amine and hydrophobically modified polyvinyl amine) on inorganic montmorillonite clay faces using adsorption isotherms and FTIR spectroscopy to characterise the nature of the chemical bonds in the clay. Factors affecting the adsorption of these polymers on clay were identified and the adsorption behaviour of the various polymers compared. 4 refs. USA

Accession no.883649 Item 30 Polymer 44, No.7, 2003, p.2091-100

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USA

Accession no.883639 Item 31 Polymer 44, No.7, 2003, p.2033-40 POLYMER/LAYERED SILICATE NANOCOMPOSITES BY COMBINED INTERCALATIVE POLYMERIZATION AND MELT INTERCALATION: A MASTERBATCH PROCESS Lepoittevin B; Pantoustier N; Devalckenaere M; Alexandre M; Calberg C; Jerome R; Henrist C; Rulmont A; Dubois P Mons Hainaut,University; CRESMAP; Liege,University The preparation of poly(epsilon-caprolactone) and PVC layered silicate nanocomposites by a combination of intercalative polymerisation and melt intercalation is described and a study of the formation of these nanocomposites by X-ray diffraction and TEM as well as the determination of their heat stabilities as a function of clay content by TGA are reported. The preparative process involved the in-situ polymerisation of epsiloncaprolactone intercalated organo-modified silicate layers and the addition of the resulting highly filled nanocomposites in the form of masterbatches in poly(epsilon-caprolactone) and PVC by melt blending. 24 refs. BELGIUM; EUROPEAN COMMUNITY; EUROPEAN UNION; WESTERN EUROPE

Accession no.883633 Item 32 2002 PLACE Conference. Proceedings of a conference held Boston, Ma., 9th-12th Sept. 2002. Atlanta, GA, TAPPI Press, 2002, Session 3, Paper 11, pp.4, CD Rom, 012

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References and Abstracts

POLYMER-CLAY NANOCOMPOSITES: ONE WAY TO IMPROVE THE BARRIER PROPERTIES OF POLYMERS USED IN PACKAGING Krook M; Hedenqvist M S Sweden,Institute for Packaging and distribution; Sweden,Royal Institute of Technology (TAPPI) Barrier packaging materials based on nanocomposites are examined. Polymer nanocomposites show high stiffness and s strength and barrier properties, with far less filler content than comparable conventional glass- or mineralfilled polymers. Tests were carried out on an experimental grade of polyesteramide and a C18-amine organoclay. It was found that both the oxygen and the water vapour transmission rate showed a modest decrease with increasing filler content. Incorporation of clay nanoparticles has been shown to significantly reduce permeability of polymers as well as increase their heat distortion temperature. In this project, a modest decrease in oxygen and water permeability with increasing content of polyesteramide/ octadecylammonium-treated montmorillonite clay, when going from 0-13 wt.% was observed. 15 refs. EUROPEAN UNION; SCANDINAVIA; SWEDEN; USA; WESTERN EUROPE

Accession no.883483 Item 33 Journal of Applied Polymer Science 87, No.14, 1st April 2003, p.2216-20 RUBBER-CLAY NANOCOMPOSITE BY SOLUTION BLENDING Pramanik M; Srivastava S K; Samantaray B K; Bhowmick A K Indian Institute of Technology A nanocomposite of EVA rubber (45% vinyl acetate content) and organomodified clay (12-Memontmorillonite) was prepared by solution blending of the rubber and the clay. A combination of X-ray diffraction, SEM and TEM studies showed that the composites obtained were on the nanometer scale. Measurements of the dynamic mechanical properties for different compositions over the temperature range -100 to +100C showed that the storage moduli of these rubberclay nanocomposites were higher above the Tg than for the neat rubber. The TS of the nanocomposites was about 1.6 times higher than that of the EVA-45. 20 refs. INDIA

Accession no.883251 Item 34 Journal of Applied Polymer Science 88, No.1, 4th April 2003, p.189-93 EFFECT OF NANOSILICA ON THE PROPERTIES OF POLYESTER-BASED POLYURETHANE

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Shu-Xue Zhou; Li-Min Wu; Jian Sun; Wei-Dian Shen Fudan,University; Eastern Michigan,University Polyester-urethanes with embedded nanosilica particles were prepared. The viscosity of polyester resins without and with nanosilica, the dispersion, and the mechanical and optical properties of the PUs with embedded nanosilica were investigated using rheoviscometry, TEM, hardness testing, scanning probe microscopy, abrasion and tensile testing, and UV-visible spectrophotometry. The viscosity of the polyester resins increased as the nanosilica content increased. It was shown that nanosilica could be dispersed into the polyester and its PU on a nanoscale. The addition of a small amount of nanosilica increased the hardness, abrasion resistance and tensile properties of the polymer films. These properties could, however, be worsened at higher nanosilica contents. The UV-visible spectra showed that the absorbance and reflection of UVvisible light by the PU films increased as the nano-silica content increased, especially at wavelengths of 290 to 400 nm. 11 refs. CHINA; USA

Accession no.883222 Item 35 Polymer Degradation and Stability 80, No.1, 2003, p.171-82 IN-SITU REACTIVE BLENDING TO PREPARE POLYSTYRENE-CLAY AND POLYPROPYLENECLAY NANOCOMPOSITES Dongyan Wang; Wilkie C A Marquette,University Nanocomposites of PS and PP with organically-modified clay were prepared by melt blending in a Brabender mixer. The presence of maleic anhydride was shown to increase the likelihood of nanocomposite formation of PS but was less important for PP. The materials obtained were immiscible materials in that the clay was not uniformly distributed throughout the polymer matrix, but there was polymer inserted between the clay layers. The results of cone calorimetry studies suggested that nanocomposite formation had occurred, as there was a significant reduction in the peak heat release rate. 33 refs. USA

Accession no.883202 Item 36 Polymer Degradation and Stability 80, No.1, 2003, p.163-9 PREPARATION AND FLAMMABILITY PROPERTIES OF POLYETHYLENE-CLAY NANOCOMPOSITES Jinguo Zhang; Wilkie C A Marquette,University PE-clay nanocomposites were prepared by melt blending in a Brabender mixer. X-ray diffraction and TEM were used to characterise the nanostructure of the composites,

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while the thermal stability was evaluated by TGA and the flammability by cone calorimetry. It was found that the PE-clay nanocomposites had a mixed immiscibleintercalated structure and that there was better intercalation when maleic anhydride was combined with the polymer and clay to be melt-blended. The reduction in peak heat release rate was 30 to 40%. 12 refs. USA

Accession no.883201 Item 37 China Synthetic Rubber Industry 26, No.2, 2003, p.115 EFFECT OF ORGANOMONTMORILLONITE MODIFIED WITH DIFFERENT INTERCALANTS ON PROPERTIES OF EPDM/CLAY NANO COMPOSITES Organomontmorillonite was modified with octadecyltrimethyl ammonium chloride, bis(2hydroxyethyl)methyl dodecyl ammonium chloride and octadecyl dimethyl benzyl ammonium chloride (DBAM) and the effect of the modified organomontmorillonite on the mechanical properties and dynamic mechanical properties of EPDM nanocomposites made therefrom. Nanocomposites containing the DBAM-modified organomontmorillonite were found to exhibit the best properties. 2 refs. CHINA

Accession no.883075 Item 38 Polymer 44, No.5, 2003, p1391-9 POLYIMIDE/MONTMORILLONITE NANOCOMPOSITES BASED ON THERMALLY STABLE, RIGID-ROD AROMATIC AMINE MODIFIERS Zhu-Mei Liang; Jie Yin; Hong-Jie Xu Shanghai,Jiao Tong University

Item 39 Materials and Processing - Ideas to Reality. Vol. 34. Proceedings of the 34th International SAMPE technical conference held Baltimore, Md., 4th-7th Nov.2002. Carina, Ca., SAMPE International Business Office, 2002, p.692-704, 23 cm, 012 THERMAL AND MECHANICAL PROPERTIES OF VINYLESTER BASED LAYERED SILICATE NANOCOMPOSITES Hussain F; Dean D Tuskegee,University (SAMPE) The effects of nano clay particles such as montmorillonite on improving mechanical and thermal properties of polymer matrix composite materials are examined. Basic correlations between polymer morphology, strength, modulus, toughness and thermal stability of thermoset nanocomposites are investigated as a function of layered silicate content. S2 glass-vinyl ester nanocomposites are prepared by adding different weight percentages of montmorillonite nano clay particles to vinyl ester matrices. The fabrication of S2 glass vinyl ester/organophillic clay nanocomposites is conducted by a cost effective vacuum assisted resin infusion moulding (VARIM) process via in situ intercalative polymerisation. The results show significant improvements in mechanical and thermal properties of the nanostructured materials with low loading of organo silicates, which offer promise of economically improving the performance of the fibre reinforced composites. Thermal property measurement includes thermogravimetric analysis and glass transition temperature. This new family of materials exhibits enhanced mechanical properties such as interlaminar shear strength, flexural strength, flexural modulus and fracture toughness. Optical and scanning electron microscopy are used to examine the failure surfaces. Molecular dispersion of the layered silicate within the crosslinked matrix is verified using wide angle X-ray diffraction and transmission electron microscopy, revealing that intercalated nanocomposites are formed. 20 refs. USA

New amine modifiers with a rigid-rod structure and which were thermally stable were developed and used for treating montmorillonite (MMT) clays prior to in situ polymerisation of polyimide (PI) onto the clay. A wider layer spacing was observed between MMT layers, and higher ion exchange ratio, compared to the use of conventional modifiers. PI/MMT nanocomposites were characterised using dynamic mechanical thermal analysis, thermogravimetric analysis, differential scanning calorimetry, X-ray diffraction, transmission electron microscopy and stress-strain properties. Properties of the nanocomposites were generally better than those prepared using conventional coupling agents, with both strength and toughness increased in the composite up to a MMT addition of 3 percent. Solvent uptake was also reduced. 31 refs. CHINA

Accession no.882876

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Accession no.882798 Item 40 Macromolecular Materials and Engineering 287, No.12, 30th Dec.2002, p.909-14 EVA COPOLYMER BASED NANOCOMPOSITES La Mantia F P; Lo Verso S; Dintcheva N T Palermo,University Nanocomposites are a new class of polymer material with an ultrafine phase dispersion of the order of a few nanometers that shows very interesting properties often very different from those of conventional filled polymers. The mechanical and optical properties of EVA copolymerbased nanocomposites are investigated to evaluate its possible use in several applications. For example, films for covering greenhouses made by EVA copolymer are

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References and Abstracts

appealing because of their interesting optical properties and for the so-called greenhouse effect. Mechanical properties and the rigidity in particular are, on the contrary, quite low. Nanocomposites should avoid this shortcoming if optical properties and processability are not unfavourably affected. EVA copolymer based nanocomposites are prepared by compounding polymer matrix and two different functionalised silicates (0-10 wt.%) in molten state. X-ray diffractograms show that, in the adopted experimental conditions, no exfoliation of the filler is obtained, but an intercalated morphology is observed. Rheological behaviour, both in shear and in non-isothermal elongational flow, is only slightly influenced by the presence of the filler. As for the mechanical properties, the elastic modulus strongly increases without any worsening of the elongation at break. Permeability in the UV region is not influenced by adding even relatively high contents of the silicates. The improved mechanical and optical properties and the unmodified processability suggest then the use of these new polymeric systems in many applications and in particular as films for covering greenhouses. 15 refs.

Item 42 ANTEC 2002. Proceedings of the 60th SPE Annual Technical Conference held San Francisco, Ca., 5th-9th May 2002. Brookfield, Ct., SPE, 2002, Paper 596, Session W13Composites. Joint with Engineering Properties and Structure. Nanocomposites I, pp.5, CD-ROM, 012 MODIFIED CLAY IN POLYVINYLCHLORIDE (PVC) Kalendova A; Kovarova L; Malac Z; Malac J; Vaculik J; Hrncirik J; Simonik J Zlin,Tomas Bata University (SPE) Poly(vinyl chloride) (PVC) nanocomposites were prepared by blending PVC with two different montmorillonites and plasticisers of different molecular weights, using a reciprocating screw blender. An increase in Young’s modulus was obtained. When significant bonding occurred between the matrix and the clay, the abrasion resistance of the in nanocomposite was not adversely affected. In the absence of bonding, the abrasion resistance was decreased. The nanocomposites exhibited enhanced heat resistance compared with PVC, particularly when good exfoliation was achieved. 6 refs.

EUROPEAN COMMUNITY; EUROPEAN UNION; ITALY; WESTERN EUROPE

CZECH REPUBLIC

Accession no.882669

Accession no.882331

Item 41 Composites Science & Technology 63, Nos.3-4, 2003, p.331-7 MORPHOLOGY, THERMAL AND MECHANICAL BEHAVIOUR OF POLYAMIDE 6/ LAYERED-SILICATE NANOCOMPOSITES Liu T X; Liu Z H; Ma K X; Shen L; Zeng K Y; He C B Singapore,Institute of Materials Research & Engineering The microstructure, morphology, thermal and mechanical properties of polyamide 6/layered-silicate nanocomposites (PLSN) are studied using X-ray diffraction (XRD), tapping-mode atomic force microscopy (AFM), differential scanning calorimetry (DSC) and tensile tests. XRD and AFM results indicate that the organically-modified layered silicates are intercalated in the polyamide 6 (PA6) matrix. Also, the crystallisation and thermal behaviour of PA6 are influenced by the addition of layered silicates into polymer matrix. A silicate-induced crystal transformation from the alpha-form to the gamma-form of PA6 is confirmed by XRD and DSC, i.e. the formation of gamma crystal is enhanced by the presence of silicates. In comparison to PA6, the thermal property of PLSN is investigated using DSC. The possible origins of a new silicate-induced endothermic peak are discussed. Tensile tests show that the tensile modulus and yield strength increase while the strain-at-yield decreases with increasing clay loading. 26 refs.

Item 43 ANTEC 2002. Proceedings of the 60th SPE Annual Technical Conference held San Francisco, Ca., 5th-9th May 2002. Brookfield, Ct., SPE, 2002, Paper 595, Session W13Composites. Joint with Engineering Properties and Structure. Nanocomposites I, pp.5, CD-ROM, 012 EFFECTS OF PROCESSING PARAMETERS ON THE PREPARATION OF HIGH DENSITY POLYETHYLENE/LAYERED SILICATE NANOCOMPOSITES Kwak M; Lee M; Lee B-K LG Chem Ltd. (SPE) Batch mixing was used to determine the optimum processing parameters for the preparation of nanocomposites comprising high density polyethylene (HDPE), organically modified clay and maleated polyethylene (PE-MAH). The degree of clay exfoliation was determined by X-ray diffraction and transmission electron microscopy. The d-spacing increased linearly with PE-MAH content, with exfoliation occurring at additions in excess of 25 wt%. Nanocomposites were subsequently prepared using an intermeshing, co-rotating twin screw extruder. Intercalation/exfoliation was enhanced by increasing the processing temperature, time, and the screw speed, and by decreasing the HDPE molecular weight. Exfoliation was influenced by shear stress on the clay and diffusion of HDPE into the clay gallery, the former being more dominant in this system. 13 refs.

SINGAPORE

KOREA

Accession no.882624

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Accession no.882330

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References and Abstracts

Item 44 ANTEC 2002. Proceedings of the 60th SPE Annual Technical Conference held San Francisco, Ca., 5th-9th May 2002. Brookfield, Ct., SPE, 2002, Paper 593, Session W13Composites. Joint with Engineering Properties and Structure. Nanocomposites I, pp.5, CD-ROM, 012 FATIGUE RESISTANCE OF POLYAMIDE-6 AND POLYAMIDE-6/CLAY NANOCOMPOSITE Bellemare S C; Bureau M N; Denault J; Dickson J I Montreal,Ecole Polytechnique; Canada,National Research Council (SPE) The fatigue resistances of polyamide-6 (PA6) containing 2 wt% montmorillonite and unfilled PA6 were compared. Longitudinal and transverse strains of injection moulded samples were measured during constant stress amplitude fatigue testing at 5 Hz. The fatigue resistances were similar. It was concluded that strain amplitude was best compared at the same maximum cyclic stress, whilst the accumulated strain at fracture was best compared at the same strain amplitude. The clay addition influenced the fatigue crack propagation mechanism, with crack initiation occurring in the bulk at or near to the clay particles. 12 refs. CANADA

Accession no.882328 Item 45 ANTEC 2002. Proceedings of the 60th SPE Annual Technical Conference held San Francisco, Ca., 5th-9th May 2002. Brookfield, Ct., SPE, 2002, Paper 592, Session W13Composites. Joint with Engineering Properties and Structure. Nanocomposites I, pp.5, CD-ROM, 012 POLYOLEFIN NANOCOMPOSITES USING MALEIC ANHYDRIDE MODIFIED POLYOLEFINS Lee J A; Gopakumar T G; Kontopoulou M; Parent J S Kingston,Queen’s University (SPE) Nanocomposites were prepared by melt blending 3-10 wt% modified montmorillonite clays with high density polyethylene and with high density polyethylene maleated with 1 wt% maleic anhydride (MA). The presence of MA gave strong interaction between matrix and clay, resulting in complete exfoliation. The clay additions accelerated the non-isothermal crystallisation of the PE. The viscous and elastic properties increased with increasing clay content, and the tensile strength was also enhanced, compared with pure PE and PE/clay mixtures. However, the elongation at break was significantly decreased. 11 refs. CANADA

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Item 46 Polymer International 52, No.1, Jan.2003, p.153-7 PREPARATION AND CHARACTERIZATION OF ETHYLENE VINYL ACETATE COPOLYMER/ MONTMORILLONITE NANOCOMPOSITE Cheol Hwan Jeon; Sung Hun Ryu; Young-Wook Chang Kyung Hee,University; Han Yang,University Ethylene-vinyl acetate (EVA) copolymer/montmorillonite (MMT) nanocomposites were prepared by melt blending. The effects of the vinyl acetate content and molecular weight of EVA on the intercalation behaviour of MMT in the EVA/MMT nanocomposites were studied. The interlayer distance of MMT increased with increasing vinyl acetate content up to 15 wt% but above that, no further increase of interlayer distance occurred. The molecular weight of EVA did not affect the intercalation behaviour. Various organomodified MMTs were used to examine the effects of substituted alkylammoniums on the dispersion of MMT in the EVA/MMT nanocomposites. The type of substituted alkylammonium played a critical role for the intercalation of MMT and dimethyldioctadecylammonium was suitable for the EVA nanocomposite. Maleic anhydride grafted HDPE (PEMA) was used as a compatibiliser to improve the intercalation behaviour of MMT. Intercalation/ exfoliation behaviour was obtained at 20 wt% PEMA. The tensile strength and elongation at break decreased, and the Young’s modulus increased, with increasing MMT content. Adding PEMA improved the tensile strength and elongation at break. 12 refs. KOREA

Accession no.881325 Item 47 Polymer Engineering and Science 43, No.1, Jan.2003, p.214-22 STUDY OF THE EFFECT OF SURFACTANTS ON THE PROPERTIES OF POLYSTYRENEMONTMORILLONITE NANOCOMPOSITES Wei Xie; Jyh Ming Hwu; Jiang G J; Buthelezi T M; Wei-Ping Pan Western Kentucky,University; Chung-Yuan Christian University PS-organomontmorillonite(organo-MMT) nanocomposites were prepared by suspension free radical polymerisation of styrene in dispersed organophilic montmorillonite. X-ray diffraction and TEM studies indicated that exfoliated nanocomposites were achieved. The effect of organic modifiers (surfactants) on the properties of the nanocomposites was studied. It was found that, under the experimental conditions studied, PSMMT nanocomposite with 5.0 wt % organo-MMT gave the greatest improvement in thermal stability and PSMMT nanocomposites with 7.5 wt % organo-MMT showed the greatest improvement in mechanical properties, compared with that of pure PS. The alkyl chain length of surfactant used in fabricating organo-MMT

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References and Abstracts

affected the PS nanocomposites synthesised, the Tg of the PS nanocomposite increasing with increase in alkyl chain length of the surfactant. The organoclay in the nanocomposites appeared, however, to play a dual role. It acted as a nanofiller leading to an increase of storage modulus and as a plasticiser leading to a decrease in storage modulus. 20 refs. TAIWAN; USA

Accession no.881051 Item 48 Polymer Engineering and Science 43, No.1, Jan.2003, p.204-13 NYLON 10 10-MONTMORILLONITE NANOCOMPOSITE MADE BY INTERCALATING POLYMERIZATION Guosheng Zhang; Yongjin Li; Deyue Yan; Youyong Xu Shanghai,Jiao Tong University The above nanocomposite was prepared by intercalating polymerisation and was characterised by X-ray diffraction, FTIR, atomic force microscopy, SEM, TGA, DSC and DMA. The results obtained showed that there were uniformly dispersed silicate layers in the nylon 1010 matrix. The resulting nanocomposites had higher onset decomposition temperature and dynamic storage moduli than those of pure nylon 1010. In addition, it was found that montmorillonite played an important role in heterophase nucleation of the crystallisation of nylon 1010 in composites. Mechanical testing showed that the tensile modulus of nanocomposites was superior to that of nylon 1010 and the ultimate strain values of the nanocomposites remained at a level similar to nylon 1010 if the content of montmorillonite was not more than 6 wt %. 22 refs. CHINA

Accession no.881050 Item 49 Journal of Applied Polymer Science 87, No.12, 21st March 2003, p.1901-9 NANOSTRUCTURE OF EVA/ORGANOCLAY NANOCOMPOSITES. EFFECTS OF KINDS OF ORGANOCLAYS AND GRAFTING OF MALEIC ANHYDRIDE ONTO EVA Li X; Ha C-S Hebei,University of Technology; Pusan,National University The nanostructure of EVAC/montmorillonite nanocomposites prepared by melt intercalation was investigated using X-ray diffraction and TEM. Three kinds of organoclays were used to examine their influences on the nanostructure of the EVAC hybrids. The effects of the polar interactions between the polymer and the silicate layers of organoclays were also investigated by grafting maleic anhydride onto EVAC. 28 refs. CHINA; KOREA

Accession no.880968

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Item 50 Macromolecular Rapid Communications 23, No.16, 25th Nov.2002, p.943-7 NEW POLYLACTIDE/LAYERED SILICATE NANOCOMPOSITE: NANOSCALE CONTROL OVER MULTIPLE PROPERTIES Ray S S; Yamada K; Ogami A; Okamoto M; Ueda K Toyota Technological Institute; Unitika Ltd. A polylactide/organically modified layered silicate (synthetic fluorine mica) nanocomposite was prepared and characterised. Wide angle X-ray diffraction and highresolution TEM showed that intercalated stacked and disordered/exfoliated mica layers coexisted in the nanocomposite. The nanocomposites showed improved mechanical properties and crystallisation behaviour with a simultaneous improvement in biodegradability compared with neat polylactide. 19 refs. JAPAN

Accession no.880688 Item 51 Macromolecular Symposia No.189, 2002, p.105-10 SHEAR CONTROLLED MORPHOLOGY OF RUBBER/ORGANOCLAY NANOCOMPOSITES AND DYNAMIC MECHANICAL ANALYSIS Schon F; Thomann R; Gronski W Freiburg,Universitat SBR/layered silicate composites are prepared using clays modified with alkyl ammonium salts of different structure. The influence of modifier structure and compounding conditions on the extent of exfoliation/intercalation of the silicates is investigated by electron microscopy and dynamic mechanical analysis. With increasing exfoliation, the glass transition temperature is lowered and the stability of the filler network is enhanced. 10 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.880600 Item 52 Fire & Materials 26, No.6, Nov.-Dec.2002, p.247-53 FLAMMABILITY OF POLYSTYRENE LAYERED SILICATE (CLAY) NANOCOMPOSITES: CARBONACEOUS CHAR FORMATION Morgan A B; Harris R H; Kashiwagi T; Chyall L J; Gilman J W US,National Inst.of Standards & Technology; Great Lakes Chemical Corp. Polymer layered-silicate (clay) nanocomposites have not only the unique advantage of reduced flammability but also improved mechanical properties. This is a key advantage over many flame retardants, which reduce flammability but also reduce the mechanical properties of the polymer. In efforts to further understand the

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References and Abstracts

mechanism of flame retardancy with polymer-clay nanocomposites, the effects of clay, loading level and polymer melt viscosity on the flammability of PS-clay nanocomposites are investigated. The nanoscale dispersion of the clay in the polymer is analysed by wide-angle X-ray diffraction (XRD) and transmission electron microscopy (TEM). Cone calorimetry and gasification studies are used to evaluate the flammability of these nanocomposites. There are major reductions in peak heat release rates (HRRs) and increased carbonaceous char formation, for these nanocomposites. It is determined that while viscosity of the PS nanocomposite plays a role in lowering the peak HRR, clay loading level has the largest effect on peak HRR. Finally, it is found that clay catalysed carbonaceous char formation and reinforcement of the char by the clay is responsible for the lowered flammability of these nanocomposites. 27 refs. USA

Accession no.880580 Item 53 Machine Design 75, No.3, 6th Feb.2003, p.28 NANOCOMPOSITES BODY PANELS ON THE HORIZON A new process, which could make nanocomposites feasible for the manufacture of automotive parts, such as body panels, has been developed by scientists at Ford Motor Co. The process involves the use of sound waves to increase the compatibility between microscopic smectite clay particles and plastics, such as PP and PE. FORD MOTOR CO. USA

Accession no.880030 Item 54 Polymer 44, No.3, Feb.2003, p.857-66 NEW POLYLACTIDE-LAYERED SILICATE NANOCOMPOSITES. II. CONCURRENT IMPROVEMENTS OF MATERIAL PROPERTIES, BIODEGRADABILITY AND MELT RHEOLOGY Ray S S; Yamada K; Okamoto M; Ueda K Toyota Technological Institute; Unitika Ltd. Nanocomposites were prepared from polylactide(PLA) and montmorillonite modified with trimethyl octadecylammonium cation. The internal structure of the nanocomposites in the nanometer range was established by using wide-angle X-ray diffraction and TEM analyses. All the nanocomposites exhibited superior improvement in practical material properties such as storage modulus, flexural modulus, flexural strength, heat distortion temp. and gas barrier properties as compared with neat PLA. The biodegradability of

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neat PLA and a representative nanocomposite was also studied under compost and the rate of biodegradation of neat PLA was shown significantly to increase after nanocomposite preparation. The melt rheology of neat PLA and various PLA nanocomposites was also studied. 42 refs. JAPAN

Accession no.879066 Item 55 Polymer 44, No.3, Feb.2003, p.681-9 CHARACTERISTICS OF POLYVINYLPYRROLIDONE-LAYERED SILICATE NANOCOMPOSITES PREPARED BY ATTRITION BALL MILLING Chong Min Koo; Hyeong Taek Ham; Min Ho Choi; Sang Ouk Kim; In Jae Chung Korea,Advanced Institute of Science & Technology Polyvinyl pyrrolidone(PVP)/sodium montmorillonite(MMT) nanocomposites prepared by the solution intercalation method were investigated by UV/ visible spectroscopy, SEM, X-ray diffraction, TEM, FTIR spectroscopy and polarised light microscopy. PVP/MMT nanocomposites showed exfoliation below 20 wt % MMT and intercalation above this concentration. Nanocomposites retained good optical clarity and increasing heat resistance with MMT content. The compatibility between PVP and MMT and their enhanced properties could be explained by hydrogen bonding interactions. In addition, the nanocomposites prepared under more rigorous mixing conditions showed better transparency because the smaller particle sizes were induced. A study on optically clear PVP/MMT suspensions was shown to provide information on the influence of existence of polymer in aqueous solution on optical anisotropy of MMT. 39 refs. SOUTH KOREA

Accession no.879048 Item 56 Journal of Biomedical Materials Research 64A, No.1, 1st Jan.2003, p.114-9 LOW PERMEABILITY BIOMEDICAL POLYURETHANE NANOCOMPOSITES Xu R; Manias E; Snyder A J; Runt J Pennsylvania,State University Details are given of a nanocomposite approach for reducing gas permeability through biomedical PU membranes used in cardiac assist devices. Nanocomposites were prepared using polyurethane ureas and two organically modified layered silicates. Characterisation was undertaken using X-ray diffraction and water vapour permeability measurements. 24 refs. USA

Accession no.878824

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References and Abstracts

Item 57 ANTEC 2002. Proceedings of the 60th SPE Annual Technical Conference held San Francisco, Ca., 5th-9th May 2002. Brookfield, Ct., SPE, 2002, Paper 473, Session T46Polymer Modifiers and Additives. Student Session, pp.5, CD-ROM, 012 TENSILE PROPERTIES OF PE CLAY NANOCOMPOSITES VIA TAGUCHI BASED DESIGN OF EXPERIMENTS Miller J; Greene J California,State University (SPE)

Item 59 ANTEC 2002. Proceedings of the 60th SPE Annual Technical Conference held San Francisco, Ca., 5th-9th May 2002. Brookfield, Ct., SPE, 2002, Paper 471, Session T46Polymer Modifiers and Additives. Student Session, pp.2, CD-ROM, 012 EFFECTS OF NANOCOMPOSITES ON THE OXYGEN BARRIER PROPERTIES OF POLYETHYLENE McConaughy S D Pennsylvania,University (SPE)

Nanocomposites of low density polyethylene (LDPE) and high density polyethylene (HDPE) were prepared by melt mixing the polymers with polypropylene-clay nanocomposites using one of maleic anhydride, acrylic acid or isopropyl alcohol as compatibiliser. The blends were extruded, pelletised and injection moulded to form tensile test specimens. Taguchi methodology was used to investigate the influences of composition and processing conditions on the tensile properties. The tensile modulus and strength of the polyethylene increased with increasing clay content, greater increases for HDPE being observed than for LDPE. Clay conditions reduced the elongation. Maleic anhydride and acrylic acid additions enhanced the mechanical properties, whilst isopropyl alcohol had little effect. 7 refs.

The barrier properties of polyethylene containing montmorillonite were evaluated by measuring the oxygen permeability at 40 C, using an extruded tubular sample of 0.127 mm wall thickness. The results were compared with those of low, medium and high density polyethylene, and of ethylene-vinyl alcohol copolymer. It was concluded that the addition of the clay to polyethylene enhanced it barrier properties for non-polar gases such as oxygen. However, the enhanced performance was still not as good as that of typical barrier polymers, such as EVOH. 3 refs.

USA

Accession no.878308 Item 58 ANTEC 2002. Proceedings of the 60th SPE Annual Technical Conference held San Francisco, Ca., 5th-9th May 2002. Brookfield, Ct., SPE, 2002, Paper 472, Session T46Polymer Modifiers and Additives. Student Session, pp.5, CD-ROM, 012 STUDY OF BLOWN FILM NANOCOMPOSITES CONSISTING OF POLYCAPROLACTONE AND MONTMORILLONITE CLAY Thellen C; Culhane E Massachusetts,University (SPE) Blown film was prepared from polycaprolactone containing 2-5% montmorillonite. A twin-screw extruder was used with a range of processing parameters. Exfoliation, as determined by X-ray diffraction and transmission electron microscopy, was enhanced by the use of slower screw speeds and feed rates. The polymer transition temperatures were not significantly changed by the clay additions. The film tensile strength and modulus increased with increasing extruder feed rate, or reducing screw speed. 5 refs. USA

Accession no.878307

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USA

Accession no.878306 Item 60 Polymer 44, No.2, 2003, p.443-50 NEW NANOCOMPOSITE MATERIALS BASED ON PLASTICIZED POLY(L-LACTIDE) AND ORGANO-MODIFIED MONTMORILLONITES: THERMAL AND MORPHOLOGICAL STUDY Paul M -A; Alexandre M; Degee P; Henrist C; Rulmont A; Dubois P Mons Hainaut,University; Liege,University Wide angle X-ray scattering, differential scanning calorimetry and thermogravimetric analysis were used to characterise new nanocomposite materials prepared by the melt mixing of a polylactide with montmorillonite clay using polyethylene glycol (PEG) as a plasticiser. Different filler levels, and both organo modified and unmodified montmorillonite samples, were used in the study, with the organo-modified materials showing the greater thermal stability at a constant filler level. Increasing filler levels also increased thermal stability. It was observed that intercalation into the interlayer spacing was by both polylactide and PEG, with competition between the materials due to polar attractions with the clay. 19 refs. BELGIUM; EUROPEAN COMMUNITY; EUROPEAN UNION; WESTERN EUROPE

Accession no.878182 Item 61 SPE Automotive TPO Global Conference 2001. Proceedings of a conference held Dearborn, Mi., 1st3rd Oct.2001.

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References and Abstracts

Brookfield, Ct., SPE, 2001, Paper 27, p.271, 27 cm, 012 LIGHTWEIGHT NANOCOMPOSITES FOR AUTOMOTIVE APPLICATIONS Kumar S R MERS LLC (SPE,Detroit Section) Clay exfoliation, prerequisite for nanoscale dispersion, may be achieved by chemical or physical means. Chemical means of achieving exfoliation is popular and its success has been demonstrated with certain polymerclay nanocomposite systems. Chemical exfoliation involves several sequential steps: modification with organic surfactants followed by monomer intercalation and in situ polymerisation. Chemical methods are generally tedious, less versatile and economically unattractive. Physical methods extant, on the other hand, use thermal and/or rheomechanical operations to break down the aggregate mineral structure with shear-induced dispersive forces, which invariably produce irreversible changes in structure with significant degradation in aspect ratio of clay particles. A simple rheological technique involving extensional flow to delaminate clay particles with little/no degradation in their aspect ratio has been developed, which offers many advantages. 3 refs.

Item 63 Industrial & Engineering Chemistry Research 41, No.25, 11th Dec.2002, p.6402-8 STRATEGIES FOR OPTIMIZING POLYPROPYLENE-CLAY NANOCOMPOSITE STRUCTURE Marchant D; Jayaraman K Michigan,State University An investigation was carried out into the effect of various amounts of maleated PP compatibilisers on the structure of nanocomposites produced by melt mixing PP with organically modified layered silicates using X-ray diffraction, TEM and melt rheological measurements. The degree of delamination in these nanocomposites was also investigated by analysing TEM images of each sample using a product of the single particle volume fraction and the intrinsic viscosity of such particles. This product was found to correlate directly with the ratio of low shear complex viscosity magnitude of the molten composite to that of the silicate-free mixture and the molar ratio of functional groups to compatibiliser chains was established as a good parameter for ranking compatibiliser effectiveness. 19 refs. USA

Accession no.877384

USA

Accession no.877729 Item 62 Journal of Materials Chemistry 12, No.12, Dec.2002, p.3528-32 POLYESTER LAYERED SILICATE NANOHYBRIDS BY CONTROLLED GRAFTING POLYMERIZATION Lepoittevin B; Pantoustier N; Alexandre M; Calberg C; Jerome R; Dubois P Mons Hainaut,University; Liege,Center for Education & Research on macromolecules; CRESMAP Poly-epsilon caprolactone layered silicate nanohybrids were prepared by ring-opening polymerisation of epsilon-caprolactone using a well-controlled coordination-insertion mechanism. Montmorillonite was modified by exchange of constitutive sodium cations with ammonium cations having one hydroxy function acting as precursors to aluminium or tin alkoxides and used to initiate polymerisation of the epsilon-caprolactone. The effects of the hydroxy functionality of the clay surface and nature of the catalyst on the molec.wt. and MWD of the polyepsilon-caprolactone and on the degree of exfoliation were examined and the nanohybrids obtained characterised by small-angle X-ray diffraction, TEM and thermogravimetry. 21 refs. BELGIUM; EUROPEAN COMMUNITY; EUROPEAN UNION; WESTERN EUROPE

Accession no.877404

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Item 64 Journal of Polymer Science: Polymer Physics Edition 41, No.1, 1st Jan.2003, p.94-103 POLY(LACTIC ACID) NANOCOMPOSITES WITH VARIOUS ORGANOCLAYS. I. THERMOMECHANICAL PROPERTIES, MORPHOLOGY AND GAS PERMEABILITY Jin-Hae Chang; Yeong Uk An; Gil Soo Sur Yeungnam,University; Kumoh,National University of Technology Nanocomposites were prepared from poly(lactic acid) (PLA) and three types of organoclay: hexadecylaminemontmorillonite (C16-MMT), dodecyltrimethylammonium bromide-montmorillonite (DTA-MMT) and commercial Cloisite 25A. The nanocomposites were characterised by thermogravimetric analysis, wide-angle X-ray diffraction, scanning electron microscopy, transmission electron microscopy and tensile testing. The clay layers were found to be dispersed homogeneously in the matrix polymer, although some aggregates were seen. The degradation temperature of the nanocomposites decreased linearly with an increased amount of clay, although with DTA-MMT the temperature remained constant at up to 8% clay by weight. The tensile properties improved to a maximum with clay loading and then declined. The oxygen permeability of the nanocomposites was less than half that of PLA alone for all three clays. 36 refs. SOUTH KOREA

Accession no.877160

© Copyright 2003 Rapra Technology Limited

References and Abstracts

Item 65 Journal of Polymer Science: Polymer Physics Edition 41, No.1, 1st Jan.2003, p.63-7 PHASE TRANSITION IN POLYAMIDE-66/ MONTMORILLONITE NANOCOMPOSITES ON ANNEALING Xiaohui Liu; Qiuju Wu; Qingxin Zhang; Zhishen Mo Lulea,University of Technology; Changchun,Institute of Applied Chemistry X-ray diffraction was used to investigate the solid-to-solid phase transition from the alpha- to the gamma- phase that occurs before melting during the annealing of polyamide66 (PA66), and the effects of the presence of nanoscale montmorillonite clay particles on the transition. The phase transition in PA66/montmorillonite nanocomposite occurred at 170C, 20C lower than in the bulk polymer. This reduction of the transition temperature was attributed to the favourable interactions between the gamma-phase structure and the nanoclay layers. 31 refs. CHINA; EUROPEAN UNION; SCANDINAVIA; SWEDEN; WESTERN EUROPE

Accession no.877157 Item 66 Journal of Polymer Science: Polymer Physics Edition 41, No.1, 1st Jan.2003, p.44-54 EFFECTS OF ORGANOCLAYS ON MORPHOLOGY AND THERMAL AND RHEOLOGICAL PROPERTIES OF POLYSTYRENE AND POLY(METHYL METHACRYLATE) BLENDS Gelfer M Y; Hyun H Song; Lizhi Liu; Hsiao B S; Chu B; Rafailovitch M; Mayu Si; Zaitsev V New York,State University at Stony Brook; Hannam,University; New York,Queens College Nanocomposites of polystyrene (PS), poly(methyl methacrylate) (PMMA), and PS/PMMA blends with Cloisite commercial organoclays were prepared by melt blending and characterised by transmission electron microscopy, small-angle X-ray scattering, secondary ion mass spectroscopy, differential scanning calorimetry and oscillatory shear rheometry. The clay particles were well dispersed and delaminated in the PS nanocomposites, but aggregated in PMMA. In the blends the clay particles were concentrated in the PMMA phase and the interfacial regions. The blends remained immiscible, but the nanocomposite blends showed a reduction in domain size of an order of magnitude compared to ordinary PS/PMMA blends. The effect of the surfactant used in preparation of the organoclays, dimethyl dioctadecyl ammonium chloride, on the blend miscibility was investigated. Like the clay, the surfactant was concentrated in the PMMA and interfacial regions, but the domain size reduction was much lower when the surfactant was added alone then in the nanocomposites. The nanocomposites had similar rheological properties to the polymers alone, suggesting weak clay-polymer interaction. The results as a whole

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were interpreted to suggest that the extent of clay exfoliation and other properties are controlled by interactions between the polymer matrix and the surfactant than between the polymer and the clay. 26 refs. SOUTH KOREA; USA

Accession no.877155 Item 67 Journal of Polymer Science: Polymer Physics Edition 41, No.1, 1st Jan.2003, p.31-8 INTERCALATED POLY(VINYLIDENE FLUORIDE)/CLAY NANOCOMPOSITES: STRUCTURE AND PROPERTIES Priya L; Jog J P Pune,National Chemical Laboratory Polyvinylidene fluoride (PVDF)/bentonite clay nanocomposites were prepared by melt intercalation and characterised by X-ray diffraction, differential scanning calorimetry and dynamic mechanical analysis. The clay was made organophilic by prior treatment with dimethyl dehydrogenated tallow ammonium chloride. X-ray diffraction indicated that the PVDF was intercalated into the clay and was in its beta crystalline form. Nonisothermal DSC showed that the nanocomposite had increased melting and crystallisation temperatures and a lower degree of crystallinity by comparison with the base polymer. Isothermal crystallisation studies showed that the addition of clay increased the rate of crystallisation. DMA indicated that the nanocomposite had a significantly improved storage modulus to the base polymer over a temperature range of -100C to 150C. 27 refs. INDIA

Accession no.877153 Item 68 Journal of Materials Science 37, No.22, 15th Nov.2002, p.4831-8 ULTRAFAST SYNTHESIS OF BENTONITEACRYLATE NANOCOMPOSITE MATERIALS BY UV-RADIATION CURING Decker C; Zahouily K; Keller L; Benfarhi S; Bendaikha T; Baron J CNRS Details are given of the preparation of nanocomposites made of silicate platelets dispersed in a polyurethaneacrylate by photopolymerisation. The mineral filler was treated with an ammonium salt or an acrylated amine to make it organophilic and allow the acrylic resin containing a photoinitiator to penetrate into the expanded organoclay galleries. The disappearance of the reactive function was followed by FTIR to evaluate both the formulation reactivity and the final cure extent of the nanocomposite. 42 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; WESTERN EUROPE

Accession no.876964

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References and Abstracts

Item 69 Polymer 44, No.1, 2003, p.289-93 INTERCALATED POLYPYRROLE/NA+MONTMORILLONITE NANOCOMPOSITE VIA AN INVERTED EMULSION PATHWAY METHOD Kim J W; Liu F; Choi H J; Hong S H; Joo J Inha,University; Korea,University Intercalated polypyrrole/Na+-montmorillonite nanocomposites were synthesised by an inverted emulsion polymerisation method using dodecylbenzenesulphonic acid as both an emulsifier and a dopant. X-ray diffraction studies showed that the nanocomposite had a layered structure. The electrical conductivity of the nanocomposite was lower than that of pure polypyrrole over a broad range of temperatures. The nanocomposites showed not only typical electrorheological behaviour with electric fields but also the existence of a critical electrical field when the yield stress of the nanocomposite-based electrorheological fluids was plotted as a function of an electric field. 41 refs. SOUTH KOREA

Accession no.876751 Item 70 Journal of Vinyl and Additive Technology 8, No.4, Dec.2002, p.238-45 PREPARATION OF PVC-CLAY NANOCOMPOSITES BY SOLUTION BLENDING Wang D; Wilkie C A Marquette,University Nanocomposites were prepared by solution blending PVC with sodium montmorillonite and an organically modified clay using THF, as solvent, and the layered structure of these nanocomposites characterised by TEM and X-ray diffraction. The thermal degradation of the composites was investigated by TGA and mechanical properties determined by tensile testing. It was found that solution blending produced a mixed immiscible-intercalated nanocomposite and that the presence of clay caused a change in the degradation path of the polymer. 28 refs. USA

Accession no.876667 Item 71 Polymer Engineering and Science 42, No.12, Dec.2002, p.2369-82 EFFECTS OF MOLECULAR WEIGHT AND CLAY ORGANO-IONS ON THE MELT INTERCALATION OF POLY(ETHYLENE OXIDE) INTO LAYERED SILICATES Shen Z; Simon G P; Cheng Y-B Australia,CSIRO; Monash,University Nanocomposites of PEO and layered silicate with either sodium cations or organically modified ammonium

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cations in the galleries of montmorillonite were prepared by melt intercalation and investigated by DSC, TGA and X-ray diffraction. The effects of polymer molec.wt., nature of the clay and the presence of water molecules in the clay galleries on melt intercalation were explored and a preliminary structural model of the nanocomposites and a model for the conformation of PEO in the clay galleries were derived. 26 refs. AUSTRALIA

Accession no.876633 Item 72 EURADH 2002. Adhesion ’02. Proceedings of a conference held Glasgow, 10th-13th Sept.2002. London. IOM Communications Ltd., 2002, Session 7; Chemistry and Rheology, Paper 9, p.141-4, 29cm, 012 THE MECHANICAL AND FRACTURE PROPERTIES OF THERMOSETS MODIFIED WITH MICRO- AND NANO-PARTICLES Tarrant A E; Kinloch A J; Taylor A C London,Imperial College of science,technol.& med. (Institute of Materials) The preparation of PMMA-clay nanocomposites by insitu intercalative polymerisation and their characterisation by X-ray diffraction and DMTA are described. The effects of clay loading on the microstructure of the nanocomposites and of microstructure on the Tg of the nanocomposites are examined and three possible microstructures are briefly discussed. 1 ref. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.876573 Item 73 ANTEC 2002. Proceedings of the 60th SPE Annual Technical Conference held San Francisco, Ca., 5th-9th May 2002. Brookfield, Ct., SPE, 2002, Paper 446, Session T42Plastics Environmental. Physical Property Enhancement of Recycled Polymers, pp.4, CD-ROM, 012 UPGRADING RECYCLED WASTE STREAM POLYETHYLENE BY MODIFICATION WITH NANOSCALE CLAY HYBRIDS Puttarudraiah A H; Goettler L A Akron,University (SPE) Recycled polyethylene was melt mixed with organically modified montmorillonite using maleic anhydride-grafted polyethylene (PE-MA) oligomer as a compatibiliser. Samples for tensile testing were prepared by compression moulding, and clay dispersion was assessed by X-ray diffraction and transmission electron microscopy. The mechanical properties improved with increasing clay and PE-MA content. Clay dispersion increased with increasing PE-MA content. The mechanical properties were

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References and Abstracts

adversely affected by excessive PE-MA additions, attributed to its inferior mechanical properties. Optimum results were achieved using the highest clay content and 14% PE-MA. 6 refs.

nanocomposites also had glass transition temperatures up to 12 C higher and exhibited significant reductions in melt viscosity. 16 refs.

USA

EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.876536

Accession no.876474

Item 74 ANTEC 2002. Proceedings of the 60th SPE Annual Technical Conference held San Francisco, Ca., 5th-9th May 2002. Brookfield, Ct., SPE, 2002, Paper 406, Session T35Blow Molding. Innovations in Blow Molding 2002, pp.5, CD-ROM, 012 HIGH BARRIER BLOW MOLDED CONTAINERS BASED ON NANO CLAY COMPOSITES Kenig S; Ophir A; Shepelev O; Weiner F Israel Plastics & Rubber Center (SPE)

Item 76 ANTEC 2002. Proceedings of the 60th SPE Annual Technical Conference held San Francisco, Ca., 5th-9th May 2002. Brookfield, Ct., SPE, 2002, Paper 381, Session T31Engineering Properties and Structure. Joint with Composites. Polymer Nanocomposites, pp.5, CDROM, 012 NANOCOMPOSITES STUDY OF ETHYLENE CO-VINYL ALCOHOL AND MONTMORILLONITE CLAY Lucciarini J M; Ratto J A; Koene B E; Powell B US,Army Soldier & Biological Chemical Command; Triton Systems Inc.; Southern Clay Products Inc. (SPE)

Containers of 10 and 22 litre capacity were extrusion blow moulded using high density polyethylene (HDPE) containing 2-5% exfoliated nanoclay, the processing being optimised to maximise the clay orientation parallel to the container surface. Loss of xylene and Fuel C by permeability from the containers at 23 and 50 C was compared with that from HDPE containers. The incorporation of the small amounts of nanoclay reduced the permeation by a factor of 70-100. In addition, the top load stiffness and dimensional stability of the containers were enhanced with no loss of impact resistance. 3 refs. ISRAEL

Accession no.876496 Item 75 ANTEC 2002. Proceedings of the 60th SPE Annual Technical Conference held San Francisco, Ca., 5th-9th May 2002. Brookfield, Ct., SPE, 2002, Paper 384, Session T31Engineering Properties and Structure. Joint with Composites. Polymer Nanocomposites, pp.5, CDROM, 012 NYLON 12-LAYERED SILICATE NANOCOMPOSITES Lew C Y; Murphy W R; McNally T; McNally G M Belfast,Queen’s University (SPE) A synthetic fluoromica, with and without ion exchange with quaternary alkylammonium, was melt compounded with polyamide-12 using a single screw extruder to obtain layered silicate nanocomposites. Wide angle X-ray diffraction, and transmission and scanning electron microscopies showed that use of the modified clay gave an exfoliated morphology. Significant increases in elongation at break, tensile strength and flexural modulus were also obtained, compared with polyamide-12. The

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Ethylene-vinyl alcohol (EVOH) containing 5 wt% montmorillonite was prepared using a twin screw extruder, blown into film and evaluated for food packaging applications. Film formation enhanced the clay delamination and dispersion compared with the compounded composite. The composite film exhibited significantly higher values of Young’s modulus and tensile strength compared with pure EVOH. The nanocomposite oxygen transmission rates were dramatically reduced, and it is proposed that the film was suitable for military ration packaging applications. 10 refs. USA

Accession no.876471 Item 77 ANTEC 2002. Proceedings of the 60th SPE Annual Technical Conference held San Francisco, Ca., 5th-9th May 2002. Brookfield, Ct., SPE, 2002, Paper 380, Session T31Engineering Properties and Structure. Joint with Composites. Polymer Nanocomposites, pp.5, CDROM, 012 MIXING AND STABILIZATION EFFECTS ON MECHANICAL PROPERTIES OF POLY(VINYL CHLORIDE)/LAYERED SILICATE NANOCOMPOSITES Hinojosa-Falcon L A; Goettler L A Akron,University (SPE) Plasticised poly(vinyl chloride)/organomontmorillonite nanocomposites were prepared by melt mixing. The influences of clay, plasticiser, and stabiliser contents, and of temperature and mixing time on the tensile properties of compression moulded samples were investigated. The

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most significant variable was clay concentration. Mechanical properties were also enhanced by: decreasing the plasticiser content (attributed to increased clay matrix interaction); and by increasing the mixing temperature and reducing the mixing time. 7 refs. USA

Accession no.876470 Item 78 ANTEC 2002. Proceedings of the 60th SPE Annual Technical Conference held San Francisco, Ca., 5th-9th May 2002. Brookfield, Ct., SPE, 2002, Paper 379, Session T31Engineering Properties and Structure. Joint with Composites. Polymer Nanocomposites, pp.5, CDROM, 012 STRUCTURE OF NANOCOMPOSITE FOAMS Changchun Zeng; Xiangmin Han; Lee L J; Koelling K W; Tomasko D L Ohio,State University (SPE) An intermeshing, co-rotating twin-screw extruder and insitu polymerisation were used to prepare polystyrene/clay nanocomposites, using carbon dioxide as the blowing agent. Cellular structure was studied by scanning and transmission electron microscopies. The presence of the clay particles resulted in a reduction in cell size and an increase in cell density, the highest densities and lowest cell sizes occurring when the clay was exfoliated. 9 refs.

in lower shear which prevented polymer degradation, whilst still achieving acceptable clay exfoliation. 8 refs. USA

Accession no.876464 Item 80 ANTEC 2002. Proceedings of the 60th SPE Annual Technical Conference held San Francisco, Ca., 5th-9th May 2002. Brookfield, Ct., SPE, 2002, Paper 373, Session T28Extrusion. Nanocomposites, pp.5, CD-ROM, 012 TWIN SCREW EXTRUSION GUIDELINES FOR COMPOUNDING NANOCOMPOSITES Andersen P G Coperion Corp. (SPE) Three alternative screw configurations were evaluated for the twin-screw extruder compounding of montmorillonite clay-containing polypropylene nanocomposites. Intercalation was enhanced by the use of higher molecular weight PP, and by adding the clay, polymer and compatibiliser at the first barrel, rather than feeding the clay downstream. Intercalation decreased slightly with increasing screw speed. Dispersive, distributive and masterbatch screw configurations had little influence on intercalation. The flexural modulus increased with increasing intercalation (d-spacing). 8 refs. USA

Accession no.876463

USA

Accession no.876469 Item 79 ANTEC 2002. Proceedings of the 60th SPE Annual Technical Conference held San Francisco, Ca., 5th-9th May 2002. Brookfield, Ct., SPE, 2002, Paper 374, Session T28Extrusion. Nanocomposites, pp.5, CD-ROM, 012 TWIN SCREW EXTRUSION OF POLYURETHANE NANOCOMPOSITES McLaughlin E A; Koene B E Triton Systems Inc. (SPE) Nanocomposites were prepared using a polyether-based polyurethane and 5-15 wt% organically modified montmorillonite, using a co-rotating twin-screw extruder with three alternative configurations and two temperature settings. Filler exfoliation was determined by transmission electron microscopy, and the nanocomposites were characterised by measurements of melt flow index, tensile properties, water vapour and diesel fuel permeability, and water and fuel resistance. The nanocomposites exhibited superior properties to those of the neat polymer, optimum properties being developed in those materials in which good exfoliation was achieved. It was concluded that the use of appropriate temperature profiles and screw design resulted

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Item 81 Chemistry of Materials 14, No.11, Nov.2002, p.4654-61 NEW POLYLACTIDE/LAYERED SILICATE NANOCOMPOSITES: ROLE OF ORGANOCLAYS Maiti P; Yamada K; Okamoto M; Ueda K; Okamoto K Toyota Technological Institute; Unitika Ltd. Organic modifiers of various chain lengths were examined in different types of clays, i.e. smectite, montmorillonite and mica, in order to prepare their corresponding organoclays. The layered structure and gallery spacing of organoclays and polylactide nanocomposites showed that, with a modifier of the same chain length, the gallery spacing of the organoclay was largest for mica and smallest for smectite because of the higher ion exchange capacity of mica and physical jamming of the modifier due to a restricted conformation at the core part of the clay of larger size. The increment of the modulus in a smectite nanocomposite, compared with that of polylactide, was higher than in MMT or mica nanocomposite due to better dispersion in a smectite system for the same clay loading. Smectite nanocomposites exhibited better gas barrier properties than the MMT or mica systems. 29 refs. JAPAN

Accession no.875596

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References and Abstracts

Item 82 Journal of Macromolecular Science B B41, No.4-6, 2002, p.1249-65 NUCLEATING EFFECT OF MONTMORILLONITE NANOPARTICLES IN POLYPROPYLENE Pozsgay A; Frater T; Papp L; Sajo I; Pukanszky B Budapest,Institute of Chemistry; Budapest,University of Technology & Economics The nucleation effect of two layered montmorillonite silicates of different origins was studied in PP. Montmorillonite was shown significantly to affect the crystallisation of PP. The effect was highly dependent on the origin and treatment of the filler, both treatment and composite preparation method leading to significant changes in the separation distance of the silicate layers. Even though the composites contained fillers with more than one population of layer distances, the nucleating effect was related to the completely collapsed galleries of 1 nm distance. Apart from gallery distance, organophilisation also modified the surface tension of the filler, but this did not influence its nucleating efficiency. The efficient gallery distance was twice as large as the characteristic matching lattice dimension determined by Lotz et al. Although a few observations could not be explained and the tentative explanation given earlier could need further verification, the results proved that nucleation did not occur at the flat surface of the filler but between its galleries, where polymer molecules could adsorb preferentially. 37 refs. (European Conference on Macromolecular Physics: Morphology and Properties of Crystalline Polymers, Eger, Hungary, Sept.2001) EASTERN EUROPE; HUNGARY

Accession no.875566 Item 83 European Polymer Journal 39, No.1, Jan.2003, p.85-91 MORPHOLOGY AND PROPERTIES OF WATERBORNE POLYURETHANE/CLAY NANOCOMPOSITES Kim B K; Seo J W; Jeong H M Pusan,National University; Ulsan,University The preparation of nanocomposites based upon an aqueous emulsion of a PU ionomer and organophilic clay and the particle size, morphology, mechanical properties and physical properties of these nanocomposites are described. The effects of the organoclay, which is intercalated or exfoliated in the PU matrix, on the modulus, tensile strength, hardness, thermal properties, water resistance and transparency of the nanocomposites are discussed. 21 refs. KOREA

Accession no.875408 Item 84 Polymer Degradation and Stability 79, No.1, 2003, p.111-21

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PROCESSING DEGRADATION OF POLYAMIDE 6/MONTMORILLONITE CLAY NANOCOMPOSITES AND CLAY ORGANIC MODIFIER Davis R D; Gilman J W; VanderHart D L US,National Inst.of Standards & Technology The thermal degradation of in-situ polymerised montmorillonite/polyamide-6 nanocomposites during injection moulding at 300C was investigated and the injection moulded materials characterised by solution Carbon-13 NMR spectroscopy, IR spectroscopy, GPC and thermogravimetric analysis. It was found that a four-fold increase in epsilon-caprolactam content and a significant reduction in number-average molec.wt. of the processed polyamide-6 occurred. A possible degradation mechanism, involving hydrolysis and peptide bond scission, was developed to account for the results obtained. 26 refs. USA

Accession no.875387 Item 85 Polymer Vol.43, No.22,2002, p.5915-33 EFFECT OF ORGANOCLAY STRUCTURE ON NYLON 6 NANOCOMPOSITE MORPHOLOGY AND PROPERTIES Fornes T D; Yoon P J; Hunter D L; Keskkula H; Paul D R Texas,University at Austin; Southern Clay Products Inc. A selected series of organic amine salts were ion exchanged with sodium montmorillonite to form organoclays varying in amine structure or exchange level relative to the clay. Using a twin screw extruder, each organoclay was melt-mixed with a high molecular grade of nylon 6 (HMW) and some organoclays were also mixed with a low molecular grade of nylon 6 (LMW). The effect of amine structure on nanocomposite morphology and physical properties was evaluated using wide angle X-ray scattering, transmission electron microscopy, and stress-strain behaviour studies. Three surfactant structural factors were identified which significantly affected nanocomposite morphology and properties in the case of the HMW nylon 6. These were decreasing the number of long alkyl tails from two to one tallows, using methyl rather than hydroxy-ethyl groups, and using an equivalent amount of surfactant with the montmorillonite, rather than adding excess, which leads to greater extents of silicate platelet exfoliation, increased moduli, higher yield strengths, and lower elongation at break. Similar surfactant structure behaviour was exhibited by LMW nanocomposites. Overall, higher extents of platelet exfoliation and better mechanical properties were exhibited by nanocomposites based on HMW nylon 6 compared with nanocomposites formed from the LMW polyamide, irrespective of the organoclay used. An explanation for

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this trend is the higher melt viscosity and consequent higher shear stresses generated during melt processing. 36 refs. USA

Accession no.873361 Item 86 Organic-Inorganic Hybrids II: Science. Technology. Applications. Proceedings of a conference held Guildford, UK, 28th-29th May 2002. Teddington, Paint Research Association, 2002, Paper 28, p.1-6, 29 cm, 012 CURRENT PROBLEMS WITH THE USE OF REACTIVE MELT PROCESSING TO PRODUCE CLAY/POLYMER NANOCOMPOSITES Fengge Gao; Zhaohui Han; Shuaijing Chen; Hull J B Nottingham,Trent University (Paint Research Association) The main problems in using reactive melt processing to produce clay/polymer nanocomposites are discussed, particular attention being paid to the degradation of organoclays and to the lack of understanding of the mechanism of melt intercalation. Future prospects for the successful application of melt intercalation in commercial nanocomposite production are considered. 14 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.873284 Item 87 Organic-Inorganic Hybrids II: Science. Technology. Applications. Proceedings of a conference held Guildford, UK, 28th-29th May 2002. Teddington, Paint Research Association, 2002, Paper 27, p.1-10, 29 cm, 012 MELT COMPOUNDED POLYPROPYLENE/ CLAY NANOCOMPOSITES Kretzschmar B; Pospiech D; Jehnichen D; Janke A Dresden,Institute of Polymer Research (Paint Research Association) Polypropylene/silicate(montmorillonite) nanocomposites with improved adhesion between silicate layers and polymer matrix were prepared by a melt compounding process. Studies were conducted of the influence of modification of the layered silicate on the exfoliation, the influence of interfacial tension between silicate and polymer matrix and the influence of the process design on the nanocomposite performance. 7 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.873283 Item 88 Polymer Engineering and Science 42, No.9, Sept.2002, p.1928-37 BIODEGRADABLE POLYESTER LAYERED

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SILICATE NANOCOMPOSITES BASED ON POLY(EPSILON-CAPROLACTONE) Pantoustier N; Lepoittevin B; Alexandre M; Kubies D; Calberg C; Jerome R; Dubois P Mons Hainaut,University; Liege,University; CRESMAP Nanocomposites based on biodegradable poly(epsiloncaprolactone)(PCL) and layered silicates (montmorillonite(MMT)) were prepared either by melt intercalation with PCL or by in-situ ring-opening polymerisation of epsilon-caprolactone as promoted by the coordination-insertion mechanism. Both non-modified clays and silicates modified by either non-functional long alkyl chains or chains terminated by carboxylic acid or hydroxyl groups were studied. Depending on the surface modification of MMT, nano- or microcomposites were obtained with specific mechanical or thermal properties. It was also shown that the formation of PCL-based nanocomposites depended not only on the ammonium cation and related functionality but also, for the same cation, on the synthetic route. 25 refs. BELGIUM; EUROPEAN COMMUNITY; EUROPEAN UNION; WESTERN EUROPE

Accession no.873200 Item 89 Polymer Engineering and Science 42, No.9, Sept.2002, p.1907-18 FOAM PROCESSING AND CELLULAR STRUCTURE OF POLYPROPYLENE/CLAY NANOCOMPOSITES Pham Hoai Nam; Maiti P; Okamoto M; Kotaka T; Nakayama T; Takada M; Ohshima M; Usuki A; Hasegawa N; Okamoto H Toyota Technological Institute; Kyoto,University; Toyota Central R & D Laboratories Inc. PP/clay nanocomposites(PPCNs) were autoclave-foamed in a batch process. Foaming was performed using supercritical carbon dioxide at 10 MPa, within the temp. range 130.6 to 143.4C, i.e. below the m.p. of either PPCNs or maleic anhydride(MA)-modified PP matrix without clay. The foamed PP-MA and PPCN2 (prepared at 130.6C and containing 2 wt % clay) showed closed cell structures with pentagonal and/or hexagonal faces, while foams of PPCN4 and PPCN7.5 (prepared at 143.4C, 4 and 7.5 wt % clay) had spherical cells. SEM confirmed that foamed PPCNs had high cell density of 10,000,000 to 100,000,000 cells/mL, cell sizes in the range of 30 to 120 micrometres, cell wall thicknesses of 5 to 15 micrometres and low densities of 0.05 to 0.3 g/mol. TEM observations of the cell structure showed biaxial flow-induced alignment of clay particles along the cell boundary. The correlation between foam structure and rheological properties of the PPCNs is also discussed. 15 refs. JAPAN

Accession no.873198

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References and Abstracts

Item 90 Polymer Engineering and Science 42, No.9, Sept.2002, p.1897-906 ROLE OF CRYSTALLINITY AND REINFORCEMENT IN THE MECHANICAL BEHAVIOR OF POLYAMIDE-6/CLAY NANOCOMPOSITES Bureau M N; Denault J; Cole K C; Enright G D Canada,National Research Council The mechanical behaviour of compression-moulded polyamide-6 reinforced with 2 wt % organo-nanoclay (montmorillonite intercalated with omegaaminododecanoic acid) was studied and compared with that of polyamide-6. The TS and the Young’s modulus of the polyamide-6/clay were 15% higher than those of polyamide-6. A crystallinity of 25% with a dual structure composed of the gamma and alpha forms was observed in the composite, while a crystallinity of 31% with the alpha form as the dominant crystalline structure was obtained in polyamide-6. The improvements in rigidity and strength observed when montmorillonite was added to polyamide-6 were found to be related to the reinforcing filler and not to a modification of the crystalline structure. 21 refs. CANADA

Accession no.873197 Item 91 Polymer Engineering and Science 42, No.9, Sept.2002, p.1883-96 EFFECT OF PRESSURE AND CLAY ON THE CRYSTALLIZATION BEHAVIOR AND KINETICS OF POLYAMIDE-6 IN NANOCOMPOSITES Kamal M R; Borse N K; Garcia-Rejon A McGill University; Canada,National Research Council

Nair S V; Goettler L A; Lysek B A Massachusetts,University; Akron,University; Solutia Inc. Results are presented of a fracture mechanics study of fracture toughness of polyamide-66 polymers with different types of nanoscale clay and mixed nanoscale/ microscale particulate reinforcements. Both fracture initiation and fracture propagation components of toughness are considered. The results obtained are compared with toughness levels imparted by conventional kaolin clay particulate reinforcements. Indirect evidence is obtained that damage zones of the order of a few hundred microns form around crack tips, which may be the reason why the toughness is not optimal in these composites. 17 refs. USA

Accession no.873195 Item 93 Polymer Engineering and Science 42, No.9, Sept.2002, p.1864-71 EFFECT OF CRYSTALLIZATION ON THE STRUCTURE AND MORPHOLOGY OF POLYPROPYLENE/CLAY NANOCOMPOSITES Maiti P; Pham Hoai Nam; Okamoto M; Kotaka T; Hasegawa N; Usuki A Toyota Technological Institute; Toyota Central R & D Laboratories Inc.

CANADA

The effect of crystallisation on the structure and morphology of maleic anhydride-grafted PP/ clay(montmorillonite) nanocomposites(PPCNs) was studied. Wide-angle X-ray diffraction(WAXD) measurements of PPCNs crystallised at different temps. showed that the extent of intercalation increased with the crystallisation temp. The enhancement of intercalation occurred with lower clay content PPCNs and maximum intercalation took place for 4 wt % clay content. A mechanism of intercalation through crystallisation is proposed. Excess gamma-form of the crystallite of PPMA appeared in the presence of clay, possibly because of the confinement of the polymer chain between the clay particles. WAXD data also revealed that d-spacing increased gradually with clay content. The decrease of spherulitic size with increasing clay content was observed, which indicated that clay particles acted as nucleating agents. Lamellar textures were examined by small-angle X-ray scattering and TEM, which showed that both the lamellar thickness and long period of the PPCNs were higher than those of PP-MA. 12 refs.

Accession no.873196

JAPAN

Item 92 Polymer Engineering and Science 42, No.9, Sept.2002, p.1872-82 TOUGHNESS OF NANOSCALE AND MULTISCALE POLYAMIDE-6,6 COMPOSITES

Item 94 Polymer Engineering and Science 42, No.9, Sept.2002, p.1841-51 MANIPULATING THE MICROSTRUCTURE

The crystallisation kinetics of polyamide-6 and its nanocomposite with 2% clay were studied, using a pressure dilatometer (50 MPa to 200 MPa) to follow the volume changes associated with the crystallisation process. Isobaric experiments were carried out to evaluate the effect of pressure and clay on m.p. and crystallisation temp. of polyamide-6. The materials exhibited two crystallisation zones in these experiments, the initial zone involving both the gamma-form and the alpha-form of polyamide-6, while the alpha-form was dominant in the latter zone. The Avrami equation was used to fit the isothermal/isobaric crystallisation data. 26 refs.

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Accession no.873194

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References and Abstracts

AND RHEOLOGY IN POLYMER-ORGANOCLAY COMPOSITES Gelfer M; Song H H; Lizhi Liu; Avila-Orta C; Ling Yang; Mayu Si; Hsiao B S; Chu B; Rafailovich M; Tsou A H New York,State University; Hannam,University; ExxonMobil Chemical Co. A series of nanocomposites prepared by melt-blending of cloisite-based organoclays with EVA and neutralised ethylene-methacrylic acid copolymers (EMA) was investigated by DSC, small-angle X-ray scattering and rheological techniques. SAXS results indicated partial clay exfoliation in all samples. In both EMA and EVA systems, the nominal m.p. and bulk crystallinity were not significantly affected by the presence of organoclays, suggesting that clay particles were predominantly confined in the amorphous phase. In rheological measurements (above m.p.), the EVA-clay system demonstrated a solid-like rheological behaviour under the small-strain oscillatory shear, yet it was able to yield and flow under a steady shear, which was the characteristic of physical crosslinking. In contrast, the EMA-clay system exhibited a melt-like rheological behaviour, where the influence of organoclay on the thermorheological behaviour of the EMA composite was quite minimal. It was suggested that the carbonyl groups of vinyl acetate in EVA interacted with the clay surface, resulting in a strong physically crosslinking-like interaction in the melt. The interaction between EMA and clay, on the other hand, was weak because of repulsion between carboxyl anions and negatively charged clay surface. 22 refs. USA

Accession no.873192

composites were found to have enhanced storage moduli, particularly at temps. higher than the Tg of the matrix. Tgs extracted from linear viscoelastic data were found to be slightly higher for modified organoclay nanocomposites, indicating enhanced interactions between the modified organoclay and the epoxy matrix. These results were also confirmed by independent measurements of Tg using DSC. 18 refs. NANOCOR INC. CANADA

Accession no.873190 Item 96 Polymer Engineering and Science 42, No.9, Sept.2002, p.1815-26 HIGH PERFORMANCE EPOXY-LAYERED SILICATE NANOCOMPOSITES Kornmann X; Thomann R; Muelhaupt R; Finter J; Berglund L A Lulea,University of Technology; AlbertLudwigs,University; Vantico AG Nanocomposites based on high performance epoxy resin were synthesised using fluorohectorite modified by means of interlayer cation exchange using cations such as protonated dihydroimidazolines and octadecylamine. The influence of these surface modifiers on curing reactions and on the Tg of the epoxy matrix was examined. The morphology and the mechanical properties of these high performance epoxy-layered silicate nanocomposites were also investigated. 26 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; SCANDINAVIA; SWEDEN; SWITZERLAND; WESTERN EUROPE

Accession no.873189 Item 95 Polymer Engineering and Science 42, No.9, Sept.2002, p.1827-35 POLYMERIZATION COMPOUNDING: EPOXYMONTMORILLONITE NANOCOMPOSITES Wei Feng; Ait-Kadi A; Riedl B Quebec,Universite Laval A strategy for the design of intercalated montmorillonite nanocomposites was devised. A commercial organoclay, 1.34 TCN (Nanocor Inc.) with bis(2-hydroxyethyl)methyl tallow ammonium, was modified by TDI and bisphenolA(BA). TGA, FTIR spectroscopy and X-ray diffraction(XRD) results of unmodified and modified 1.34 TCN(1.34-TDI-BA) indicated that TDI and BA reacted with hydroxyl groups on the surface of 1.34 TCN and hydroxyl groups in the interlayer of 1.34 TCN. Using a classical two-stage cure process with diamine as curing agent, intercalated epoxy nanocomposites were prepared for both types of organoclays. XRD and TEM results showed that the basal spacing of clay in nanocomposites was 3.68 and 4.42 nm for 1.34 TCN and 1.34-TDI-BA, respectively. DMA was performed on both modified and unmodified organoclay composites. Modified organoclay

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Item 97 Polymer Engineering and Science 42, No.9, Sept.2002, p.1800-7 POLYPROPYLENE/CLAY NANOCOMPOSITES: EFFECT OF COMPATIBILIZER ON THE THERMAL, CRYSTALLIZATION AND DYNAMIC MECHANICAL BEHAVIOR Hambir S; Bulakh N; Jog J P India,National Chemical Laboratory PP/clay nanocomposites were prepared using different grades of PP, compatibilisers and organically-modified clays. The melt intercalation of the PP was carried out in the presence of a compatibiliser. The nanocomposites were characterised for structure and properties using various techniques. X-ray diffraction results indicated well-defined structures. TGA indicated improved thermal stability of PP/clay nanocomposites. Isothermal crystallisation studies carried out using DSC illustrated enhanced crystallisation of PP in all the nanocomposites. Optical microscopic studies demonstrated that the nanocomposites could be crystallised at higher temps.,

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References and Abstracts

exhibiting well-defined birefringent structures. DMA revealed higher storage moduli over a temp. range of 40C to 120C for nanocomposites and the extent of increase in the storage modulus was dependent on the type of compatibiliser used. 20 refs.

using Schapery’s equation. Nanocomposites containing 5% clay exhibited similar viscoelastic behaviour to that of pure PP at low stress values. 6 refs. USA

Accession no.872885

INDIA

Accession no.873187 Item 98 ANTEC 2002. Proceedings of the 60th SPE Annual Technical Conference held San Francisco, Ca., 5th-9th May 2002. Brookfield, Ct., SPE, 2002, Paper 275, Session T5Engineering Properties and Structure. Polypropylene Nanocomposites, pp.5, CD-ROM, 012 SKIN-CORE EFFECTS IN POLYPROPYLENE NANOCOMPOSITES Hernandez-Luna A; D’Souza N A; Ranade A; Drewniak M North Texas,University; Solvay Engineering Polymers (SPE) Nanocomposites were prepared by blending polypropylene (PP), maleated polypropylene (mPP) and an organically-modified montmorillonite. The nanocomposites were characterised by transmission electron microscopy, X-ray diffraction, and measurements of thermal emissivity, tensile strength and fracture toughness. The clay was exfoliated in the bulk, whilst an intercalated structure was observed at the surface. This skin-core effect resulted in anisotropic properties. The addition of mPP to PP decreased the mechanical properties, but the clay additions restored the tensile properties and substantially increased the fracture toughness. 6 refs. USA

Accession no.872887 Item 99 ANTEC 2002. Proceedings of the 60th SPE Annual Technical Conference held San Francisco, Ca., 5th-9th May 2002. Brookfield, Ct., SPE, 2002, Paper 273, Session T5Engineering Properties and Structure. Polypropylene Nanocomposites, pp.5, CD-ROM, 012 CREEP AND TENSILE BEHAVIOR OF POLYPROPYLENE NANOCOMPOSITES Hernandez-Luna A; D’Souza N A North Texas,University (SPE) Nanocomposites of polypropylene with 1-5% montmorillonite, with and without an addition of maleated PP as a compatibiliser, were prepared and the structures studied by X-ray diffraction and transmission electron microscopy. Creep-recovery tests were performed on injection moulded samples. Master curves and shift factors were determined based on horizontal and vertical shifts

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Item 100 ACS Polymeric Materials: Science and Engineering. Spring Meeting. Volume 84. Proceedings of a conference held San Diego, Ca., 1st-5th April 2001. Washington, D.C., ACS,Div.of Polymeric Materials Science & Engng., 2001, Paper 354, p.645-6, 27cm, 012 SYNTHESIS OF PMR-15/LAYERED SILICATE NANOCOMPOSITES Islam M; Dean D R; Small S; Campbell S Tuskegee,University; US,NASA,Glenn Research Center (ACS,Div.of Polymeric Materials Science & Engng.) Novel polyimide-clay nanocomposites were produced by dispersing unmodified and modified montmorillonite clays into a polyamic acid solution and the properties of the nanocomposites determined by wide angle X-ray diffraction, TGA and dynamic mechanical analysis. The intercalated and exfoliated morphologies, heat stability and storage modulus of the nanocomposites are discussed. 7 refs. USA

Accession no.872817 Item 101 Plastics Additives & Compounding 4, No.10, Oct.2002, p.22-8 NANOCOMPOSITES - A NEW CLASS OF FLAME RETARDANTS FOR POLYMERS Beyer G Kabelwerk Eupen AG In this long and detailed article, the author reviews the current state of development of nanocomposites as a new class of flame retardants for polymers. Section headings include: introduction, layered silicates as fillers, nanocomposite synthesis, nanocomposite structures, nanocomposite properties, thermal stability, flame retardancy, flame retardant combinations, and conclusions. US,NATIONAL INST.OF STANDARDS & TECHNOLOGY BELGIUM; EUROPE-GENERAL; EUROPEAN COMMUNITY; EUROPEAN UNION; USA; WESTERN EUROPE

Accession no.872695 Item 102 Macromolecules 35, No.22, 22nd Oct.2002, p.8385-90 POLYCAPROLACTONE/CLAY NANOCOMPOSITES BY IN SITU INTERCALATIVE POLYMERIZATION

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References and Abstracts

CATALYZED BY DIBUTYLTIN DIMETHOXIDE Lepoittevin B; Pantoustier N; Devalckenaere M; Alexandre M; Kubies D; Calberg C; Jerome R; Dubois P Mons,University; Liege,University Polycaprolactone/clay nanocomposites were prepared by ring-opening polymerisation using dibutyltin dimethoxide as initiator/catalyst. The effect of surface modification, surface reactivity, and concentration of clay on the molecular weight of the composite were investigated. Morphology was characterised using X-ray diffraction and TEM. Resistance against thermal degradation was also compared by TGA. 27 refs. BELGIUM; EUROPEAN COMMUNITY; EUROPEAN UNION; WESTERN EUROPE

Accession no.872476 Item 103 SPE Automotive TPO Global Conference 2002. Proceedings of a conference held Dearborn, Mi., 30th Sept-2nd Oct.2002. Brookfield, Ct., SPE, 2002, Materials Session, p.121-9, 27cm, 012 TPO/CLAY NANOCOMPOSITES: MORPHOLOGY AND MECHANICAL PROPERTIES Mirabella F M; Bafna A; Rufener K; Mehta S Equistar Chemicals LP; Cincinnati,University (SPE,Detroit Section) Thermoplastic olefin (TPO)/clay nanocomposites are made at clay loadings from 0.6 to 5.6. The morphology of these TPO/Clay nanocomposites is investigated with atomic force microscopy (AFM) and transmission electron microscopy (TEM). The EPR particle morphology in the TPO is found to undergo progressive particle break-up and decrease in particle size, as clay loading increases in the range from 0.6 to 5.6% clay. TEM micrographs show that the clay platelets preferentially segregate to the rubber-particle interface. The clay platelets, and/or the accompanying chemical modifiers on the clay, apparently act as an interfacial agent, reducing the interfacial tension with concomitant reduction in particle size. Flexural modulus increases monotonically as clay loading increases. Impact strength modestly improves or is maintained at lower clay loadings and decreases sharply at the highest clay loading. 6 refs. USA

Accession no.872079 Item 104 Chemistry of Materials 14, No.9, Sept.2002, p.3837-43 COMPARISON OF VARIOUS METHODS FOR THE PREPARATION OF POLYSTYRENE AND POLY(METHYL METHACRYLATE) CLAY NANOCOMPOSITES Dongyan Wang; Jin Zhu; Qiang Yao; Wilkie C A

78

Marquette,University; Brooklyn,Polytechnic University Polymer-clay nanocomposites of styrene and methyl methacrylate were prepared by bulk, solution, suspension and emulsion polymerisations and by melt blending. Two different organic modifications of montmorillonite were used, one containing a styryl monomer on the ammonium ion and the other having no double bond. The organic modification as well as the mode of preparation determined whether the material would be exfoliated or intercalated. Exfoliation was more likely to occur if the ammonium ion contained a double bond which could participate in the polymerisation reaction, but the mere presence of this double bond was not sufficient always to produce an exfoliated system. Solution polymerisation also produced intercalated systems. Neither TGA nor the tensile modulus could be used to evaluate the type of nanocomposite that had been formed. 21 refs. USA

Accession no.871155 Item 105 Chemistry of Materials 14, No.9, Sept.2002, p.3776-85 POLYMER/LAYERED SILICATE NANOCOMPOSITES FROM THERMALLY STABLE TRIALKYLIMIDAZOLIUM-TREATED MONTMORILLONITE Gilman J W; Awad W H; Davis R D; Shields J; Harris R H; Davis C; Morgan A B; Sutto T E; Callahan J; Trulove P C; DeLong H C US,National Inst.of Standards & Technology; US,Naval Research Laboratory; US,Naval Academy Several trialkylimidazolium salt derivatives were prepared with propyl, butyl, decyl and hexadecyl alkyl chains attached to the imidazolium through one of the nitrogens. These imidazolium salts were used to prepare the corresponding treated layered silicates. The use of 1-alkyl2,3-dimethylimidazolium(I) salts to replace the sodium in natural montmorillonite(MMT) was shown to give organophilic MMT with a 100C improvement in thermal stability (in nitrogen) as compared with the alkylammonium-treated MMT. The use of I salt in fluorinated synthetic mica also gave a 100C improvement in thermal stability. The use of 1,2-dimethyl-3hexadecylimidazolium-treated MMT gave an exfoliated nylon-6 nanocomposite and, depending on processing conditions, either a partially exfoliated or an intercalated PS nanocomposite. 40 refs. USA

Accession no.871153 Item 106 Polymer 43, No.23, 2002, p.6147-57 STRUCTURAL CHARACTERIZATION AND TRANSPORT PROPERTIES OF ORGANICALLY

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References and Abstracts

MODIFIED MONTMORILLONITE/ POLYURETHANE NANOCOMPOSITES Tortora M; Gorrasi G; Vittoria V; Galli G; Ritrovati S; Chiellini E Salerno,University; Pisa,University PU-organically modified montmorillonite nanocomposites (montmorillonite contents between 4 and 40 wt%) were prepared by a three-step process using diphenylmethane diisocyanate, poly(epsiloncaprolactone), di(ethylene glycol) and poly(epsiloncaprolactone)-organically modified montmorillonite nanocomposites. Exfoliation occurred for low montmorillonite contents but for high contents, the intercalated clay rearranged to a minor extent. The elastic modulus and yield stress improved but the stress and strain at break decreased with increasing clay content. The sorption of water vapour or dichloromethane did not change very much with increasing clay content but the zero-concentration diffusion parameter decreased strongly with increasing clay content. The permeability was largely dominated by the diffusion parameter and showed a remarkable decrease up to 20 wt% of clay and levelled off at higher contents. 33 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; ITALY; WESTERN EUROPE

Accession no.870948 Item 107 China Synthetic Rubber Industry 25, No.3, 2002, p.173 SYNTHESIS OF RESOLE/MONTMORILLONITE NANOCOMPOSITE BY INTERCALATION POLYMERISATION Xinming L; Xialin L; Daming W Beijing,University of Chemical Technology Phenolic resin-layered-silicated nanocomposite has attracted interest recently, due to its excellent heat resistance and mechanical properties. Most studies have been concentrated on novolac resin, as it usually has a linear molecular structure, which make it easier to be inserted into clay galleries than resole resin. Few studies have been reported on resole resin as it usually has a 3D structure even before it is cured. A different polymerisation method, solution polymerisation, is proposed to minimise or overcome this problem. Montmorillonite is dipped in the monometer to make monometer enter the galleries of montmorillonite before the reaction. When the polymer is synthesised in the galleries of montmorillonite, the silicated layers are dispersed among polymers in nanoscale. The product is characterised by X-ray diffraction and transmission electron microscopy. The improved property of heat resistance is also analysed by thermogravimetry. 2 refs. CHINA

Accession no.870509

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Item 108 Polymer Preprints. Volume 41, Number 1. Proceedings of a conference held San Francisco, Ca., March 2000. Washington D.C., ACS,Div. of Polymer Chemistry, 2000, p.521-2, 28 cm, 012 SYNTHESIS OF A PMMA-LAYERED SILICATE NANOCOMPOSITE BY SUSPENSION POLYMERIZATION Huang X; Brittain W J Akron,University (ACS,Div.of Polymer Chemistry) A PMMA-layered silicate nanocomposite was prepared by in-situ suspension polymerisation using either AIBN or 2,2'-azobis(isobutylamidine hydrochloride) (AIBA), as initiator, and the mechanism of polymerisation and structures of the resulting nanocomposites investigated by means of wide angle X-ray diffraction. Two different polymerisation mechanisms are illustrated and the structure of the nanocomposite produced using AIBA as polymerisation initiator is shown to be of the exfoliated type, which is preserved after melt pressing. 19 refs. USA

Accession no.870373 Item 109 Polymers for Advanced Technologies 13, No.9, Sept. 2002, p.649-52 BARRIER PROPERTY OF CLAY/ ACRYLONITRILE-BUTADIENE COPOLYMER NANOCOMPOSITE Nah C; Ryu H J; Kim W D; Choi S-S Chonbuk,National University; Korea,Institute of Machinery & Materials; Chungnam,National University A nanocomposite was prepared by melt mixing an organotreated montmorillonite into an NBR matrix and curing the mixture with benzoyl peroxide at 170C in a compression mould. The effect of clay content on the barrier properties of the nanocomposite was investigated and the experimental results compared with predicted values obtained using Neilson’s tortuous model. Addition of a small amount of organoclay was found to markedly improve the barrier properties of the nanocomposite. 11 refs. KOREA

Accession no.870356 Item 110 Journal of Applied Polymer Science 86, No.6, 7th Nov.2002, p.1497-506 POLYLACTIDE/MONTMORILLONITE NANOCOMPOSITES AND MICROCOMPOSITES PREPARED BY MELT BLENDING: STRUCTURE AND SOME PHYSICAL PROPERTIES Pluta M; Galeski A; Alexandre M; Paul M-A; Dubois P Polish Academy of Sciences; Mons Hainaut,University

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References and Abstracts

Polylactide-based nanocomposites loaded with 3 wt% organomodified montmorillonite and polylactide-based microcomposites loaded with 3 wt% sodium montmorillonite were prepared by melt blending. The morphological and thermal properties of the composites were studied and were compared with unfilled polylactide with the same thermomechanical history. The good affinity between the organomodified clay and polylactide was sufficient to form an intercalated structure in the nanocomposite. The microcomposite formed a phase separated microstructure. The nature of the filler affected the ordering of the polylactide matrix at the molecular and supermolecular levels. The nanocomposites showed improved thermal stability in air and reduced flammability, together with char formation, compared with the microcomposite and unfilled polylactide. 19 refs. EASTERN EUROPE; EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; POLAND; WESTERN EUROPE

Accession no.868786 Item 111 Polymer 43, No.11, 2002, p.3247-55 RHEOLOGICAL BEHAVIOR OF MULTIWALLED CARBON NANOTUBE/ POLYCARBONATE COMPOSITES Potschke P; Fornes T D; Paul D R Texas,University at Austin The rheological behaviour of compression moulded mixtures of polycarbonate containing between 0.5 and 15 wt% of multiwalled carbon nanotubes was studied by means of oscillatory rheometry at 260C. The composites were obtained by diluting a masterbatch containing 15 wt% carbon nanotubes using a twin-screw extruder. The increase in viscosity associated with the addition of the nanotubes was much greater than viscosity changes caused by carbon nanofibres having larger diameters, and for carbon black composites and was explained by the higher aspect ratio of the nanotubes. The increase in viscosity was accompanied by an increase in the elastic melt properties, represented by the storage modulus, which was much higher than the increase in the loss modulus. The viscosity curves above 2 wt% nanotubes showed a larger decrease with frequency than samples containing lower nanotube loadings. Composites containing more than 2 wt% nanotubes showed non-Newtonian behaviour at lower frequencies. A step increase at about 2 wt% nanotubes was seen in the viscosity-composition curves at low frequencies and this step change was regarded as a rheological threshold. Eventually, the rheological threshold coincided with the electrical conductivity percolation threshold which occurred between 1 and 2 wt% nanotubes. 41 refs. USA

Accession no.868752

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Item 112 ANTEC 2002. Proceedings of the 60th SPE Annual Technical Conference held San Francisco, Ca., 5th-9th May 2002. Brookfield, Ct., SPE, 2002, Paper 194, Session M38Rotational Molding Materials, pp.4, CD-ROM, 012 DEVELOPMENT OF NANOCOMPOSITES TO ENHANCE FUNCTIONALITY OF MATERIALS FOR ROTATIONAL MOLDING Martin D; Halley P; Truss R; Murphy M; Meusburger S; Jackson O Queensland,University; Queensland Manufacturing Institute (SPE) Polyethylene-clay and castable thermoset polyurethaneclay nanocomposites for rotational moulding applications are reviewed. The clay particles have a high aspect ratio and may be natural or produced synthetically by hydrothermal synthesis. They require surface treatment to render them organophilic and suitable for intercalation by the polymer. In two-part polyurethane systems, the clay is dispersed in one of the low viscosity components by high shear homogenisation or ultrasonic probe prior to mixing. Introduction into polyethylene, which usually requires maleating to enhance compatibility, may be by masterbatch or one-step compounding. Low shear viscosity and melt elasticity, desirable for sintering during moulding, are obtained by the use of unmodified mica and synthetic magadite, whilst the use of surface-treated mica and natural montmorillonite result in significant viscosity and elasticity increases. 13 refs. AUSTRALIA

Accession no.868460 Item 113 ANTEC 2002. Proceedings of the 60th SPE Annual Technical Conference held San Francisco, Ca., 5th-9th May 2002. Brookfield, Ct., SPE, 2002, Paper 193, Session M38Rotational Molding Materials, pp.6, CD-ROM, 012 IMPROVING POLYETHYLENE PERFORMANCE - THE USE OF NANOCOMPOSITES IN ZIEGLER-NATTA POLYETHYLENE FOR ROTATIONAL MOULDING Murphy M J; Martin D J; Truss R; Halley P Queensland,University (SPE) Nanocomposites were prepared by melt blending a conventional medium density polyethylene containing 1% maleic anhydride with 6 wt% or 9 wt% of two organicallymodified clays, using a co-rotating twin screw extruder. The nanocomposites were characterised by dynamic mechanical thermal analysis, X-ray diffraction, crystallinity determination by differential scanning calorimetry, and parallel plate rheology studies, using compression moulded samples. The organoclay additions

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References and Abstracts

increased the melt viscosity, and also the storage moduli, particularly at higher temperatures. A slight increase in crystallinity was also observed. 7 refs. AUSTRALIA

Accession no.868459 Item 114 Composites International No.53, Sept.-Oct.2002, p.85-6 English; French MONTMORILLONITE FOR PLASTIC REINFORCEMENT Hunter D L Southern Clay Products Inc. Clay-based polymer nanocomposites are plastics that have nanometre-thick clay mineral added to improve the plastics functionality in several possible ways: reinforcement, thermal properties, barrier and flame retardancy. Montmorillonite has been used most extensively. Cloisite clay products supplied by Southern Clay Products have a nominal size of eight microns, but there are more than one million platelets in one particle. The delamination and dispersion to the platelet level is called exfoliation. Good exfoliation allows one to take advantage of the properties of montmorillonite: a surface area of 750 m2/g, an aspect ratio greater than 50 and a flexural modulus of about 170 GPa. USA

Accession no.868140 Item 115 Polymer 43, No.20, 2002, p.5483-91 INFLUENCE OF CLAY EXFOLIATION ON THE PHYSICAL PROPERTIES OF MONTMORILLONITE/POLYETHYLENE COMPOSITES Gopakumar T G; Lee J A; Kontopoulou M; Parent J S Kingston,Queen’s University Conventional montmorillonite clay/PE composites and nanocomposites of exfoliated montomorillonite platelets dispersed in a maleated PE matrix were prepared by melt compounding. The clay platelet exfoliation in the maleated PE nanocomposites significantly reduced the degree of crystallinity and increased the polymer crystallisation rates. Studies of the non-isothermal crystallisation kinetics indicated that the exfoliated clay promoted heterogeneous nucleation and two-dimensional crystallite growth. PE/clay composites showed modest increases in their rheological properties and Young’s modulus. The nanoscale dimensions of the dispersed clay platelets in the nanocomposites led to significant increases in viscous and elastic properties and improved stiffness. A mechanism for these changes was suggested. 31 refs. CANADA

Accession no.868065

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Item 116 Polymer Preprints. Volume 41, Number 1. Proceedings of a conference held San Francisco, Ca., March 2000. Washington D.C., ACS,Div.of Polymer Chemistry, 2000, p.591-2, 28cm, 012 EXFOLIATION OF MONTMORILLONITES IN EPOXY In-Joo Chin; Thurn-Albrecht T; Ho-Cheol Kim; Russell T P Massachusetts,University (ACS,Div.of Polymer Chemistry) The formation of epoxy-montmorillonite nanocomposites was investigated using time-dependent small angle X-ray scattering using synchrotron radiation and rotating anode X-ray radiation, DSC and atomic force microscopy. The influence of amine curing agent on clay exfoliation was examined and the necessity for the curing reaction to produce exfoliated nanocomposites investigated. Exfoliated nanocomposites were formed when diglycidyl ether of Bisphenol A (DGEBA) was self-polymerised with montmorillonites or when DGEBA was cured with an amine of less than equimolar concentration. An analysis of the exothermic heat evolved during exfoliation revealed that exfoliated nanocomposites could be produced without completion of the reaction. 11 refs. USA

Accession no.867931 Item 117 Polymer Preprints. Volume 41, Number 1. Proceedings of a conference held San Francisco, Ca., March 2000. Washington D.C., ACS,Div.of Polymer Chemistry, 2000, p.589-60, 28cm, 012 PREPARATION OF POLYCARBONATELAYERED SILICATE NANOCOMPOSITES Xinyu Huang; Lewis S; Brittain W J; Vaia R A Akron,University; Wright-Patterson Air Force Base (ACS,Div.of Polymer Chemistry) The preparation of intercalated and partially exfoliated polycarbonate nanocomposites from polycarbonate cyclic oligomers and an organically modified layered silicate and their characterisation by means of wide angle X-ray diffraction, TEM and gel-permeation chromatography are described. Preparative techniques involved compounding in a Brabender mixer and ring opening polymerisation. Factors important in the formation of nanocomposites are identified as molecular architecture, viscosity and shear. 20 refs. USA

Accession no.867930 Item 118 Journal of Polymer Science: Polymer Physics Edition 40, No.15, 1st Aug.2002, p.1690-703 SYNTHESIS AND STRUCTURAL CHARACTERIZATIONS OF CHROMOPHORE+-

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References and Abstracts

SAPONITE/POLYURETHANE NANOCOMPOSITES Wu-Jing Wang; Wei-Kuo Chin; Wan-Ju Wang Taiwan,National Tsing Hua University Non-linear optical nanocomposite materials were prepared by intercalating three different non-linear optical chromophores into layered aluminosilicate saponite and then dispersing the intercalated choromophore/saponite complexes into the PU matrix. The nanocomposite system showed excellent compatibility between the clay and PU, although the clay content was as high as 15 wt%. In most guest-host non-linear optical polymer systems, the glass transition temperature decreases with increasing chromophore content, but in the system studied here, the glass transition temperature of the synthesised nanocomposite proportionally increased with the clay content. The preparation method described in this paper provided a nanocomposite film with high molecular order and thermal stability. 39 refs. TAIWAN

Accession no.867521 Item 119 Polymer 43, No.19, 2002, p.5117-24 GLASS TRANSITION TEMPERATURES OF POLY(HYDROXYSTYRENE-COVINYLPYRROLIDONE-CO-ISOBUTYLSTYRYL POLYHEDRAL OLIGOSILSESQUIOXANES) Hongyao Xu; Shiao-Wei Kuo; Juh-Shyong Lee; FengChih Chang Taiwan,National Chiao-Tung University; Anhui,University A series of poly(hydroxystyrene-co-vinylpyrrolidone-coisobutylstyryl polyhedral oligosilsesquioxanes) (PHSPVP-POSS) hybrid polymers with various POSS contents were prepared and characterised. They were synthesised by the free radical copolymerisation of acetoxystyrene, vinylpyrrolidone with styrylisobutylpolyhedral oligosesquioxanes, and then selective removal of the acetyl protective group. POSS content of the hybrid polymers is controlled by varying the feed ratio of reactants. Hydrogen bonds are formed between the POSS siloxane and the PHS hydroxyl in the polymer to form the physically crosslinked POSS structure. This physically crosslinked POSS restricts the polymer chain motion and causes a significant increase in the Tg of the polymers, even with small amounts of POSS. The mechanism of Tg enhancement was investigated using DSC, FTIR and GPC. 25 refs. CHINA; TAIWAN

Accession no.866520 Item 120 Polymer Bulletin 49, No.1, Aug. 2002, p.69-76

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STRUCTURE AND THERMAL PROPERTIES OF COMPATIBILIZED PET/EXPANDABLE FLUORINE MICA NANOCOMPOSITES Saujanya C; Imai Y; Tateyama H AIST A series of PETP/expanded fluorine mica nanocomposites containing various amounts of 10-(3,5-bis(methoxycarbonyl)phenoxy)decyltriphenylphosphonium bromide (BPB), as compatibiliser, was prepared by in-situ polymerisation and the structure and thermal properties of these compatibilised nanocomposites investigated by X-ray diffraction and differential scanning calorimetry. The data obtained indicated that BPB enhanced the miscibility between the PETP and the mica, resulting in the formation of exfoliated structures. 17 refs. JAPAN

Accession no.866373 Item 121 Rheologica Acta 41, No.5, Aug.2002, p.394-407 DYNAMIC MELT FLOW OF NANOCOMPOSITES BASED ON POLYEPSILON-CAPROLACTAM Utracki L A; Lyngaae-Jorgensen J National Research Council of Canada; Denmark,Technical University The dynamic flow behaviour of polyamide-6 and a nanocomposite(PNC) based on it, containing 2 wt % organoclay, was studied. The two materials were blended in proportions of 0, 25, 50, 75 and 100 wt % PNC. The dynamic shear rheological properties of well-dried specimens were measured under nitrogen at a temperature of 240C, a frequency of 0.1-100 rad/s and a strain of 10 and 40%. The results obtained are discussed with reference to time sweeps, strain sweeps, frequency sweeps-loss modulus, intrinsic viscosity and the aspect ratio, apparent yield stress and frequency sweeps-storage modulus. 27 refs. CANADA; DENMARK; EUROPEAN COMMUNITY; EUROPEAN UNION; SCANDINAVIA; WESTERN EUROPE

Accession no.866005 Item 122 Polymer Preprints. Volume 42. Number 1. Spring 2001. Papers presented at the ACS Meeting held San Diego, Cal., 1st-5th April 2001. Washington, D.C., ACS,Div.of Polymer Chemistry, 2001, p.640-1, 28cm, 012 RHEOLOGICAL PROPERTIES OF BIODEGRADABLE ALIPHATIC POLYESTER/ MONTMORILLONITE NANOCOMPOSITES Lim S T; Hyun Y H; Choi H J; Jhon M S Inha,University; Carnegie-Mellon University (ACS,Div.of Polymer Chemistry) Nanocomposites were prepared from a biodegradable aliphatic polyester and organophilic montmorillonite

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References and Abstracts

(OMM) by solvent casting and their rheological properties investigated. It was found that these nanocomposites exhibited shear-thinning behaviour and improved storage and loss moduli with OMM loading and obeyed the Cox and Merz rule. 17 refs. KOREA; USA

Accession no.865245 Item 123 Polymer Preprints. Volume 42. Number 1. Spring 2001. Papers presented at the ACS Meeting held San Diego, Cal., 1st-5th April 2001. Washington, D.C., ACS,Div.of Polymer Chemistry, 2001, p.634-5, 28cm, 012 PREPARATION AND PROPERTIES OF NANOCOMPOSITES BASED ON POLYSULFONES AND AN ORGANOCLAY Sun H; Sur G S; Beaucage G; Mark J E Cincinnati,University; Yeungnam,University (ACS,Div.of Polymer Chemistry) Polysulphone/organoclay nanocomposites were prepared by mixing montmorillonite with a polysulphone and solvent casting and characterised by means of X-ray diffraction, small angle X-ray scattering, TEM, TGA and tensile testing. The organoclay was found to be exfoliated into nanoscale layers and homogeneously dispersed in the polysulphone matrix. The nanocomposites exhibited improved tensile properties and heat stability over the pure polymer. 7 refs. KOREA; USA

Accession no.865242 Item 124 Macromolecular Symposia Vol.183, 2002, p.95-102 LAYERED SILICATE/POLYESTER NANOHYBRIDS BY CONTROLLED RINGOPENING POLYMERISATION Lepoittevin B; Pantoustier N; Alexandre M; Calberg C; Jerome R; Dubois P Mons Hainaut,University; Liege,University; CRESMAP Layered silicate/aliphatic polyester nanohybrids are synthesised by ring-opening polymerisation of Ecaprolactone as promoted by the so-called co-ordinationinsertion mechanism. These nanocomposites are formed in the presence of montmorillonite surface-modified by ammonium cations bearing hydroxyl group(s), such as bis(2-hydroxyethyl)methyl (hydrogenated tallow alkyl) ammonium. The lactone polymerisation can be initiated by all the hydroxyl functions available at the clay surface, after activation into either tin(II) or Al(III) alkoxide active species. Hybrid nanocomposites are accordingly generated through the covalent grafting of every polyester chain onto the filler surface. Surface-grafted polycaprolactone (PCL) chains are untied and isolated

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by ionic exchange reaction with LiCl in THF solution and molar masses are measured by size exclusion chromatography. The PCL molar masses can be controlled and readily tuned by the content of hydroxyl groups available at the clay surface. Interestingly, initiation reaction by aluminium trialkoxide active species yields grafted PCL chains characterised by very narrow molecular weight distribution. These polyester-grafted layered silicate nanohybrids display complete exfoliation of silicate sheets as shown by X-ray diffraction and transmission electron microscopy. 7 refs. BELGIUM; EUROPEAN COMMUNITY; EUROPEAN UNION; WESTERN EUROPE

Accession no.864767 Item 125 Polymer Preprints. Volume 42. Number 1. Spring 2001. Papers presented at the ACS Meeting held San Diego, Ca., 1st-5th April 2001. Washington, D.C., ACS,Div.of Polymer Chemistry, 2001, p.354-5, 28cm, 012 FORMATION OF SELF GENERATING, INORGANIC PASSIVATION LAYER ON NYLON 6/LAYERED SILICATE NANOCOMPOSITE Hao Fong; Vaia R A; Sanders J H; Lincoln D; John P J; Vreugdenhil A J; Bultman J; Cerbus C A; Jeon H G Wright-Patterson Air Force Base (ACS,Div.of Polymer Chemistry) Nanoscale dispersion of only a few percentage of layered silicate (montomorillonite) in nylon-6 was shown to result in the formation of a uniform passivation layer upon exposure to oxygen plasma. The resulting inorganic layer significantly retarded the penetration of oxygen plasma and prevented further polymer degradation. The nanocomposite concept could thus potentially enhance the survivability of polymeric materials in extreme environments, especially in low earth orbit against atomic oxygen. 3 refs. USA

Accession no.863948 Item 126 Journal of Polymer Science: Polymer Physics Edition 40, No.16, 15th Aug.2002, p.1741-53 MELT BLENDING OF ETHYLENE-VINYL ALCOHOL COPOLYMER/CLAY NANOCOMPOSITES: EFFECT OF THE CLAY TYPE AND PROCESSING CONDITIONS Artzi N; Nir Y; Narkis M; Siegmann A Technion-Israel Institute of Technology Ethylene-vinyl alcohol copolymer(EVOH)/clay nanocomposites were prepared via dynamic melt blending and the effect of processing parameters on blends containing two clay types in different amounts was examined. The clays were an onium ion-modified montmorillonite and a modified montmorillonite

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containing 30-40 wt % poly(oxyethylene decyloxypropylamine). X-ray diffraction showed advanced EVOH intercalation within the galleries, whereas TEM images indicated exfoliation. A dilution process with EVOH and clay treatment in an ultrasonic bath before melt blending did not add to the intercalation level. Different trends were observed for the EVOHs containing the two different clay treatments. The m.p., crystallisation temp. and heat of fusion of the EVOH matrix decreased sharply with both increasing clay content and processing times. 15 refs. ISRAEL

Accession no.863601 Item 127 Polymer Degradation and Stability 77, No.2, 2002, p.299-304 THERMAL DEGRADATION AND RHEOLOGICAL BEHAVIOUR OF EVA/ MONTMORILLONITE NANOCOMPOSITES Riva A; Zanetti M; Braglia M; Camino G; Falqui L Torino,Universita; TILAB; Genova’Istituto di Studi Chimico-Fisici di Macromol.Sint.e Nat. Various modified phyllosilicates and EVA were mixed at 120C in a Brabender mixer in order to obtain polymer layered silicate nanocomposites. Exfoliated nanocomposites were obtained with montmorillonite exchanged with methyl tallow bis(2hydroxyethyl)ammonium and fluorohectorite exchanged with octadecylammonium, whereas with montmorillonite exchanged with dimethyl dehydrogenated tallow ammonium and fluorohectorite exchanged with amino dodecanoic acid an intercalated nanocomposite and a microcomposite were obtained, respectively. It was demonstrated that a low silicate percentage (10%) nanodispersed in the polymer matrix was capable of markedly reducing the influence of oxygen during thermooxidation and substantially increasing the storage modulus of the material. The acid catalysis of acetic acid elimination observed on heating EVA nanocomposites in nitrogen was more effective in the case of exfoliated morphologies. 11 refs. (8th European Conference on Fire Retardant Polymers, Alessandria, Italy, June 2001) EUROPEAN COMMUNITY; EUROPEAN UNION; ITALY; WESTERN EUROPE

Accession no.863592 Item 128 Polymer 43, No.18, 2002, p.5011-6 SOLID-STATE ELECTROLYTE NANOCOMPOSITES BASED ON POLYETHYLENE OXIDE, POLYOXYPROPYLENE DIAMINE, MINERAL CLAY AND LITHIUM PERCHLORATE Chen H-W; Chiu C-Y; Wu H-D; Shen I-W; Chang F-C Taiwan,National Chiao-Tung University

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Details are given of the preparation of a polyelectrolyte nanocomposite consisting of polyoxypropylene diamine and mineral clay. Specific interactions among silicate layer, polymer, ether oxygen, and lithium cation were investigated using DSC, alternating current impedance and FTIR. 29 refs. CHINA

Accession no.862373 Item 129 Polymer 43, No.18, 2002, p.4967-72 POLYMORPHISM IN POLYAMIDE 66/CLAY NANOCOMPOSITES Liu X; Wu Q; Berglund L A Lulea,University of Technology Polyamide 66/clay nanocomposites were prepared via melt compounding by using a new kind of organophilic clay which was obtained through co-intercalation of epoxy resin and quaternary ammonium into sodiummontmorillonite. Silicate layers were dispersed homogeneously and nearly exfoliated in nylon-66 matrix. The effect of the silicate layers on the crystallisation rate was determined. 55 refs. EUROPEAN UNION; SCANDINAVIA; SWEDEN; WESTERN EUROPE

Accession no.862367 Item 130 Polymer 43, No.18, 2002, p.4895-904 INTERLAYER EXPANSION MECHANISM AND THERMAL-MECHANICAL PROPERTIES OF SURFACE-INITIATED EPOXY NANOCOMPOSITES Chen J-S; Poliks M D; Ober C K; Zhang Y; Wiesner U; Giannelis E Cornell University The exfoliation mechanism and thermal-mechanical properties of surface-initiated epoxy resin nanocomposites were studied. The interlayer expansion mechanism was examined using time-resolved high-temperature X-ray diffraction, DSC, and isothermal rheological analysis. Differences in the activation energies of interlayer expansion and of curing on the final nanostructures of the materials were determined. Variations in ultimate properties were attributed to the formation of an interphase layer, where the interphase is hypothesised to be the epoxy matrix plasticised by surfactant chains. 34 refs. USA

Accession no.862360 Item 131 Chemistry of Materials 14, No.7, July 2002, p.3016-21 SYNTHESIS AND PROPERTIES OF COVALENTLY BONDED LAYERED SILICATES/ POLYIMIDE (BTDA-ODA) NANOCOMPOSITES

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References and Abstracts

Leu C-M; Wu Z-W; Wei K-H Taiwan,National Chiao-Tung University Covalently bonded layered silicates/polyimide (BTDAODA) nanocomposites are synthesised from gamma(aminopropyl)triethoxysilane (APTS) grafted kenyaite and polyamic acid. The existence of covalent bonds between APTS and silicates and between APTS and the dianhydride end groups of the polymer are confirmed by solid-state 13C and 29Si NMR and IR spectroscopy, respectively. The thermal, mechanical and moisture absorption retardation properties of these nanocomposites are found to improve substantially over those of neat BTDA-ODA. In particular, a maximum increase of 36 deg.C in the degradation temperature and a maximum reduction of 54% in moisture absorption are displayed by these nanocomposites. 37 refs. TAIWAN

Accession no.860842 Item 132 Chemistry of Materials 14, No.7, July 2002, p.2936-9 SYNTHESIS OF EXFOLIATED POLYACRYLONITRILE/NA-MMT NANOCOMPOSITES VIA EMULSION POLYMERISATION Choi Y S; Wang K; Xu M; Chung I J Korea,Advanced Institute of Science & Technology Polyacrylonitrile/Na MMT nanocomposites are synthesised through an emulsion polymerisation of acrylonitrile (AN) using 2-acrylamido-2-methyl-1-propanesulphonic acid (AMPS). The silicate (Na-MMT) layers are exfoliated during polymerisation. The nanocomposites are exfoliated up to 20 wt.% content of pristine Na-MMT relative to the amount of AN and exhibit the enhanced storage modulus, E’, when compared with pure PAN. Delaminated morphology of the nanocomposite is confirmed by TEM. 44 refs. KOREA

Accession no.860839 Item 133 Journal of Polymer Science: Polymer Physics Edition 40, No.14, 15th July 2002, p.1434-43 RHEOLOGICAL PROPERTIES OF DIBLOCK COPOLYMER/LAYERED-SILICATE NANOCOMPOSITES Mitchell C A; Krishnamoorti R Houston,University The melt-state viscoelastic properties of nanocomposites prepared with a symmetrical polystyrene-polyisoprene block copolymer and organically modified layered silicates are examined. Nanocomposites based on three thermodynamically equivalent organically modified layered silicates, primarily differing in lateral disk diameter (d), are studied with small-amplitude oscillatory shear. The effects of the domain structure of the ordered block

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copolymer and the mesoscale dispersion of the layered silicates on the rheological properties are examined via a comparison of data for the nanocomposites in the ordered and disordered states of the block copolymer. Hybrids prepared with 5 wt.% organically modified fluorohectorite and montmorillonite demonstrate a notable decrease in the frequency dependence of the moduli at low frequencies and a significant enhancement in the complex viscosity at low frequencies in the disordered state. This behaviour is understood in terms of the development of a percolated layered-silicate network structure. However, the viscoelastic properties in the disordered state with 5 wt.% organically modified laponite and in the ordered state of the block copolymer for all layered silicates demonstrate only minor changes from those observed for the unfilled polymer. 39 refs. USA

Accession no.860493 Item 134 Macromolecules 35, No.14, 2nd July 2002, p.5529-35 DEFORMATION BEHAVIOR OF POLYETHYLENE/SILICATE NANOCOMPOSITES AS STUDIED BY REALTIME WIDE-ANGLE X-RAY SCATTERING Ki Hyun Wang; In Jae Chung; Min Cheol Jang; Jong Kakh Keum; Hyun Hoon Song Korea,Advanced Institute of Science & Technology; Hannam,University Maleated PE(PEMA)/silicate nanocomposite and maleated PE/silica composite were prepared by melt compounding. TEM and X-ray scattering results confirmed the exfoliation of the silicate layers (20A) throughout the maleated PE matrix, but the silica particles were not well dispersed in the matrix. The long axes of exfoliated silicates were aligned along the tensile axis during deformation and showed no sign of cavity formation in the matrix. In PEMA/silica, however, large amounts of cavities were created along the tensile direction. During the tensile deformation, the crystallographic changes of pure PEMA and composites containing 20A and silica were investigated using realtime X-ray scattering. The 20A and silica particles in composites had little effect on the initiation of martensitic transformation, but they effectively inhibited the orientation of PE lamellae in the tensile direction. The lamellar fragmentation was higher in PEMA/20A than in PEMA/silica, while the former was less effective in inhibiting lamellar orientation. 48 refs. SOUTH KOREA

Accession no.860080 Item 135 Macromolecules 35, No.14, 2nd July 2002, p.5508-16 NANOCOMPOSITES DERIVED FROM

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SULFONATED POLY(BUTYLENE TEREPHTHALATE) Chisholm B J; Moore R B; Barber G; Khouri F; Hempstead A; Larsen M; Olson E; Kelley J; Balch G; Caraher J GE Corporate R & D; Southern Mississippi,University The effect of sodium sulphonate functionalisation of polybutylene terephthalate(PBT) on the properties of PBT/ montmorillonite composites was studied. The results showed that organic modification of montmorillonite clay coupled with the modification of PBT with low levels of SO3Na groups resulted in the production of highly exfoliated nanocomposites by a simple extrusion process. With regard to the effect of -SO3Na content, as little as 1.0 mol % -SO3Na groups was needed to achieve considerable exfoliation of organically modified montmorillonite. Although the degree of exfoliation was not observed to be strongly dependent on -SO3Na content, mechanical properties such as Young’s modulus and high-temp. storage moduli at temps. above Tg increased with increasing SO3Na content. These enhancements in mechanical properties produced by a higher -SO3Na content were due to an increase in the number of interactions between the clay particles and the matrix via electrostatic interactions involving the -SO3Na groups. 33 refs.

Item 137 Polymer 43, No.16, 2002, p.4365-73 MORPHOLOGY, THERMAL RELAXATIONS AND MECHANICAL PROPERTIES OF LAYERED SILICATE NANOCOMPOSITES BASED UPON HIGH-FUNCTIONALITY EPOXY RESINS Becker O; Varley R; Simon G Monash,University; CSIRO Details are given of the possibilities of improving the mechanical properties of epoxy resins through dispersion of octadecyl ammonium ion-modified layered silicates within the polymer matrix. All resins were cured with diethyl toluene diamine. The morphology of the cured material was examined using X-ray scattering as well as optical and atomic force microscopy. The alpha- and betarelaxation temperatures of the cured systems were determined using dynamic mechanical thermal analysis. The effect of different concentrations of the alkyl ammonium-modified layered silicate on the toughness and stiffness of the different epoxy resins was analysed. 42 refs. AUSTRALIA

Accession no.859410

USA

Accession no.860078 Item 136 Journal of Polymer Science: Polymer Physics Edition 40, No.7, 1st April 2002, p.670-7 NANOCOMPOSITES OF POLYURETHANE WITH VARIOUS ORGANOCLAYS: THERMOMECHANICAL PROPERTIES, MORPHOLOGY, AND GAS PERMEABILITY Jin-Hae Chang; Yeong Uk An Kumoh,National University of Technology The thermal stabilities, tensile properties, morphological properties and gas barrier properties of different polyurethane (PU) nanocomposites with three different organoclays were compared. The three organoclays used were: hexadecylamine-montmorillonite, dodecyltrimethyl ammonium-montmorillonite and Cloisite 25A. The properties of the nanocomposites in film form were studied as functions of the organoclay content in the matrix PU. Thermogravimetric analysis, wide-angle X-ray diffraction, scanning electron microscopy, transmission electron microscopy and tensile testing were used to study the nanocomposites. Most of the clay layers were dispersed homogeneously into the matrix polymer on the nanoscale, although some particles were agglomerated. The thermal stabilities and mechanical properties of the films were improved by the addition of only a small amount of organoclay, whereas gas permeability was reduced. 27 refs. KOREA

Accession no.859706

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Item 138 Polymer Engineering and Science 42, No.6, June 2002, p.1141-50 POLYMORPHIC BEHAVIOUR OF NYLON 6/ SAPONITE AND NYLON 6/ MONTMORILLONITE NANOCOMPOSITES Wu T-M; Chen E-C; Liao C-S I-Shou,University; Yuan Ze,University Polyamide 6/clay nanocomposites were prepared by the intercalation of epsilon-caprolactam followed by exfoliation of the layered saponite or montmorillonite by means of polymerisation. Changes in the crystal structure and behaviour of the nanocomposites were investigated by X-ray diffraction and DSC and the effect of heat treatment on the crystal structure of the nanocomposites between Tg and melting temperature examined. Evidence was found for the presence of polymorphism in the nanocomposites, which was dependent on the cooling rate of the nanocomposites from the melt and the content of clay in the nanocomposites. 28 refs. TAIWAN

Accession no.859227 Item 139 Polymer 43, No.15, 2002, p.4251-60 COMPARISON OF SOLUTION INTERCALATION AND MELT INTERCALATION OF POLYMER-CLAY NANOCOMPOSITES

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References and Abstracts

Zhiqi Shen; Simon G P; Yi-Bing Cheng CSIRO; Monash,University Nanocomposites of poly(ethylene oxide) (PEO) and organically-modified montmorillonite clays were prepared by both solution intercalation and melt intercalation, and compared by X-ray diffraction and Fourier transform infrared (FTIR) spectroscopy. The gallery size of the solution-intercalated composites increased with increasing PEO content up to 15%, whereas the gallery size of the melt-intercalated systems was constant and independent of PEO concentration. There was no difference in the FTIR spectra analysis of the solution and melt intercalated samples. It was concluded that the PEO conformation was a distorted helical structure. 45 refs. AUSTRALIA

Accession no.858719 Item 140 Polymer 43, No.15, 2002, p.4097-101 SYNTHESIS AND PROPERTIES OF POLYBENZOXAZOLE-CLAY NANOCOMPOSITES Steve Lien-Chung Hsu; Keng-Chuan Chang Taiwan,National Cheng Kung University A polybenzoxazole (PBO)-clay nanocomposite was prepared by adding a dimethylacetamide (DMAc)dispersion of organically-modified montmorillonite clay to a DMAc solution of PBO precursor, followed by solvent evaporation and thermal curing. The polyhydroxyamide precursor was synthesised by a low temperature polycondensation reaction between isophthaloyl chloride and 2,2-bis(3-amino-4hydroxyphenyl)hexafluoropropane. Clay dispersion was confirmed by X-ray diffraction and transmission electron microscopy. The composite thermal expansion decreased, whilst both the glass transition temperature and the thermal decomposition temperature increased, with increasing clay additions. 15 refs. TAIWAN

tallowalkyl-based quaternary ammonium cations. X-ray diffraction and TEM analyses showed that these nanocomposites had an intercalated/exfoliated structure. PCL microcomposites filled with natural sodium montmorillonite were prepared under the same conditions and formed a conventional composite with micron-sized particles dispersed in PCL. The tensile properties (particularly stiffness) and thermal stability of the exfoliated nanocomposites improved with the filler loading up to a content of 5 wt%. Above this filler content, these properties levelled off and/or decreased. A marked charring effect was observed on exposure to flame. A solid-like rheological response was observed for PCL modified by 3 wt% and more of organo-modified montmorillonite. 24 refs. BELGIUM; EUROPEAN COMMUNITY; EUROPEAN UNION; WESTERN EUROPE

Accession no.857644 Item 142 Chemistry of Materials 14, No.5, May 2002, p.1989-94 PREPARATION AND INTERACTION CHARACTERISTICS OF ORGANICALLY MODIFIED MONTMORILLONITE NANOCOMPOSITE WITH MISCIBLE POLYMER BLEND OF POLYETHYLENE OXIDE AND POLYMETHYL METHACRYLATE Lim S K; Kim J W; Chin I; Kwon Y K; Choi H J Inha,University The intercalation of modified montmorillonite in a polyethylene oxide/PMMA blend was demonstrated using dichloromethane as a cosolvent. X-ray diffraction was used to confirm the formation of nanoscale polymermontmorillonite hybrids and the localisation of the polymers between the organosilicate layers. Specific interaction between the components was quantified by the Flory-Huggins interaction parameters by combining the melting point depression and the binary interaction model. 31 refs. KOREA

Accession no.858701

Accession no.856786

Item 141 Polymer 43, No.14, 2002, p.4017-23 POLY(EPSILON-CAPROLACTONE)/CLAY NANOCOMPOSITES PREPARED BY MELT INTERCALATION: MECHANICAL, THERMAL AND RHEOLOGICAL PROPERTIES Lepoittevin B; Devalckenaere M; Pantoustier N; Alexandre M; Kubies D; Calberg C; Jerome R; Dubois P Mons Hainaut,University; Liege,University Poly(epsilon-caprolactone) (PCL)/clay nanocomposites were prepared by melt blending the polymer with montmorillonite organo-modified with hydrogenated

Item 143 Composites Science & Technology 62, Nos.7-8, 2002, p.1033-41 MORPHOLOGY DEVELOPMENT IN LAYERED SILICATE THERMOSET NANOCOMPOSITES Tolle T B; Anderson D P US,Air Force,Wright-Patterson Base

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The role of processing temperature on the morphology development of organically modified montmorilloniteepoxy nanocomposites is examined to determine the sensitivity of exfoliation to processing and the potential to achieve desired morphologies through processing routes. In situ small-angle X-ray scattering studies are

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performed to relate the initiation and levels of exfoliated morphologies with time and temperature. Scattering data are correlated with key stages in morphology development to provide insight into the process-morphology relationship. Absolute temperature as well as heating rate is shown to directly affect the development of exfoliated nanocomposite morphology. 25 refs. USA

Accession no.856489 Item 144 SAMPE Journal 38, No.3, May/June 2002, p.59-70 CARBON NANOTUBES AND NANOFIBERS IN COMPOSITE MATERIALS Maruyama B; Alam K Wright-Patterson Air Force Base; Ohio,University

but a reduction in specific heat change was observed for all samples exhibiting the 001 clay peak. The hardness was increased by the clay addition, but was independent of the concentration. 62 refs. USA

Accession no.856046 Item 146 Polymer 43, No.13, 2002, p.3699-705 STRUCTURE-PROPERTY RELATIONSHIPS IN CROSS-LINKED POLYESTER-CLAY NANOCOMPOSITES Bharadwaj R K; Mehrabi A R; Hamilton C; Trujillo C; Murga M; Fan R; Chavira A; Thompson A K Avery Research Center; Southern California,University

USA

Nanocomposites were prepared by dispersing 1.0-10.0 wt% organically modified montmorillonite in an unsaturated polyester resin followed by crosslinking using methyl ethyl ketone peroxide catalyst. Transmission electron microscopy showed a random dispersion of intercalated and exfoliated clay aggregates. With increasing clay content, the thermal degradation was slightly increased, the loss and storage moduli monotonically moved towards higher frequency values, and the tensile modulus decreased. The observed changes were attributed to a decrease in the degree of polymer crosslinking. The nanocomposite containing 2.5 wt% clay exhibited greater property reductions than other compositions. This was attributed to the greater degree of exfoliation and hence greater decrease in the degree of crosslinking. Oxygen permeability rates decreased with increasing clay content, fitting a tortuosity-based model. 29 refs.

Accession no.856072

USA

Carbon nanotubes and nanofibres are discussed with particular reference to the properties which make them potential candidates for a range of applications, and their ability to provide opportunities for the design of multifunctional material systems. One-dimensional nanocarbon (1D nanocarbon composites) are reviewed, in which category are included single-wall carbon nanotubes (SWNTs), multi-wall carbon nanotubes (MWNTs) and carbon nanofibres. This paper provides an overview of the current state of technology, and to identify critical issues that must be addressed before widespread application can be achieved. Following a brief summary of 1D nanocarbons and their potential benefits to composite materials, the R & D and industrial needs are examined. 54 refs.

Item 145 Polymer 43, No.13, 2002, p.3759-66 EXFOLIATED AND INTERCALATED POLYAMIDE-IMIDE NANOCOMPOSITES WITH MONTMORILLONITE Ranade A; D’Souza N A; Gnade B North Texas,University Nanocomposites were formed by adding xylene suspensions of organically modified montmorillonite clay to xylene suspensions of polyamide-imide, and films were formed by solvent evaporation. Optical microscopy showed increased edge-edge clay platelet attraction at the sample surface. Increased face-face coagulation and some edge-edge flocculated states of tactoid formation were observed through the thickness of the sample by transmission electron microscopy. High exfoliation was observed by X-ray diffraction for 1% clay additions, whilst additions of 1.5-3% resulted in intercalated and exfoliated dispersions. The glass transition temperature was not significantly influenced by the clay additions,

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Accession no.856039 Item 147 European Polymer Journal 38, No.7, July 2002, p.1383-9 NON-ISOTHERMAL CRYSTALLIZATION BEHAVIORS OF POLYAMIDE 6/CLAY NANOCOMPOSITES Xiaohui Liu; Qiuju Wu Lulea,University of Technology The non-isothermal crystallisation of polyamide 6 (PA6)/organophilic clay nanocomposites was studied using differential scanning calorimetry and X-ray diffraction. The clay particles acted as effective nucleation agents, their presence influencing the nucleation mechanism and the growth of the PA-6 crystallites. The degree of crystallinity increased with increasing cooling rate, attributed to the formation of gamma-crystalline PA-6 being favoured by the presence of the clay. 40 refs. EUROPEAN UNION; SCANDINAVIA; SWEDEN; WESTERN EUROPE

Accession no.856013

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References and Abstracts

Item 148 Polymer 43, No.10, 2002, p.2969-74 EXFOLIATION OF ORGANOCLAY IN THERMOTROPIC LIQUID CRYSTALLINE POLYESTER NANOCOMPOSITES Jin-Hae Chang; Bo-Soo Seo; Do-Hoon Hwang Kumoh,National University of Technology A thermotropic liquid crystalline polyester (TLCP) with an alkoxy side group was synthesised from 2ethoxyhydroquinone and 2-bromoterephthalic acid. Its optical texture was nematic. Nanocomposites of TLCP with an organoclay (Cloisite 25A, C25A) were prepared. Adding 2-6% of C25A to the TLCP maintained liquid crystallinity. C25A was exfoliated and dispersed homogeneously in the matrix polymer. The C25A/TLCP hybrids containing 0-6% C25A were processed for fibre spinning to study their tensile properties. The ultimate strength and initial modulus of the hybrids increased with increasing clay content and the mechanical properties reached maximum values in hybrids containing 6% of the organoclay. The thermal, morphological and thermomechanical behaviours were studied. 27 refs. SOUTH KOREA

Accession no.855448 Item 149 Polymer 43, No.10, 2002, p.2909-16 MELT COMPOUNDING OF SYNDIOTACTIC POLYPROPYLENE NANOCOMPOSITES CONTAINING ORGANOPHILIC LAYERED SILICATES AND IN SITU FORMED CORE/ SHELL NANOPARTICLES Kaempfer D; Thomann R; Muellhaupt R Albert-Ludwigs,Universitat Syndiotactic PP was melt compounded with an organophilic layered silicate (organohectorite obtained by cation exchange of fluorohectorite with octadecylammonium cations) in a corotating twin-screw extruder. Maleic anhydride-grafted isotactic PP (iPP-gMA) was used as a compatibiliser. The reinforcement of the syndiotactic PP matrix was achieved by in-situ formation of silicate nanoparticles via exfoliation combined with simultaneous in-situ encapsulation of the resulting nanosilicates in a thin shell of iPP-g-MA. Interlayer distance increased with increasing content and molecular weight of the compatibiliser. The Young’s modulus of the nanocomposite increased fivefold from 490 to 2640 MPa and this was attributed to silicate nanoreinforcement and nucleation of syndiotactic PP crystallisation via the iPP-g-MA shell of the dispersed organophilic silicate nanoparticles. The yield stress was increased. The effects of the silicate and compatibiliser content on the morphology and mechanical properties were studied. 16 refs.

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EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.855440 Item 150 Macromolecules 35, No.9, 23rd April 2002, p.3563-8 POLY(P-PHENYLENETEREPHTHALAMIDE)BASED NANOCOMPOSITES OBTAINED BY MATRIX POLYCONDENSATION. SYNTHESIS AND SOLID-STATE NMR CHARACTERIZATION Simonutti R; Mariani A; Sozzani P; Bracco S; Piacentini M; Russo S Milano-Bicocca,Universita degli Studi; Sassari,University; Genoa,University Matrix polymerisation is a suitable procedure for preparation of homogeneous blends that are otherwise difficult or practically impossible to prepare. Poly(pphenylene terephthalamide)(PPDT) was synthesised by direct polycondensation in the presence of poly(Nvinylpyrrolidone)(PVP) or poly(4-vinylpyridine) as polymer matrices. The molec.wt. effect of the latter polymers on the intrinsic viscosity of the aromatic polyamide was investigated. PPDT, characterised by intrinsic viscosity as high as 14.2 dL/g, was obtained when high molec.wt. PVP was used. The intimate composites formed in situ were characterised by solid-state NMR. The parent and daughter polymers in the composite exhibited the same proton T1 relaxation times in the rotating frame and this value differed from that of the neat polymers, this result demonstrating the intimacy of the blend at the level of a few nanometers. 30 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; ITALY; WESTERN EUROPE

Accession no.853378 Item 151 Macromolecules 35, No.9, 23rd April 2002, p.3338-41 CONTROLLED ROOM TEMPERATURE SYNTHESIS OF COFE2O4 NANOPARTICLES THROUGH A BLOCK COPOLYMER NANOREACTOR ROUTE Ahmed S R; Kofinas P Maryland,University Well-dispersed cobalt ferrite nanoparticles within a norbornene copolymer matrix were synthesised at room temp. and characterised. A modification of the previouslyreported templating schemes using block copolymers consisted of introducing a mixture of metal salts to a polymer solution before any microphase separation of the block copolymer constituents could occur, thus allowing fast diffusion of metals to the functional polymer backbone. The diblock copolymer matrix was synthesised using ring-opening metathesis polymerisation of norbornene derivatives. The self-assembly of the mixed-

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References and Abstracts

metal oxide within the polymer template was achieved at room temp. by introducing a mixture of ferric chloride and cobalt chloride into one of the functional polymer blocks and by subsequent processing of the copolymer by wet chemical methods to substitute the chlorine atoms with oxygen. Cobalt ferrite nanoparticles were thus formed within the spherical microphase-separated morphology of the diblock copolymer, which served as the templating medium. TEM, FTIR and wide-angle Xray diffraction were used to characterise the nanocomposite morphology, oxide chemical composition and process of oxide formation. 13 refs.

Melting temp. changes and residuals were measured by TGA. TS and elongation were also examined with a universal testing machine. Increases in both the thermal stability and the mechanical strength of BAP/OMMT were observed for several different OMMT loadings. The rheological properties of the BAP/OMMTs were also examined with a rotational rheometer having a parallel-plate geometry. The shear viscosity at low shear rate exhibited a Newtonian plateau even at high loading and showed a higher degree of shear thinning at higher shear rate. Both the Newtonian plateau and the enhanced power law behaviour were correlated with a scaling function. 46 refs.

USA

KOREA; USA

Accession no.853349

Accession no.853318

Item 152 Macromolecules 35, No.9, 23rd April 2002, p.3318-20 CONTROLLED RING-OPENING POLYMERIZATION OF EPSILONCAPROLACTONE IN THE PRESENCE OF LAYERED SILICATES AND FORMATION OF NANOCOMPOSITES Kubies D; Pantoustier N; Dubois P; Rulmont A; Jerome R Liege,University; Mons Hainaut,University; Belgium,Centre de Recherches en Sciences de Materiaux Polymeres

Item 154 Macromolecular Materials and Engineering 287, No.4, 26th April 2002, p.243-9 TRANSPORT PROPERTIES OF MODIFIED MONTMORILLONITE-POLY(EPSILONCAPROLACTONE) NANOCOMPOSITES Tortora M; Vittoria V; Galli G; Ritrovati S; Chiellini E Salerno,University; Pisa,University

The controlled/living polymerisation of epsiloncaprolactone(CL) was studied in the presence of montmorillonite modified by alkylammonium cations which were capable of initiating or not initiating the epsilonCL polymerisation. Tin(II) octoate was first combined with hydroxyl-containing alkylammonium cations and the polyepsilon-CL chains had to grow from the silicate surface as tethered chains. This was not the case when dibutyltin(IV) methoxide was the initiator in conjunction with inactive alkylammonium cations. 12 refs. BELGIUM; EUROPEAN COMMUNITY; EUROPEAN UNION; WESTERN EUROPE

Accession no.853344 Item 153 Chemistry of Materials 14, No.4, April 2002, p.1839-44 SYNTHETIC BIODEGRADABLE ALIPHATIC POLYESTER/MONTMORILLONITE NANOCOMPOSITES Lim S T; Hyun Y H; Choi H J; Jhon M S Inha,University; Carnegie-Mellon University Biodegradable aliphatic polyesters(BAPs), synthesised from diols and dicarboxylic acids, and organophilic montmorillonite(OMMT) were intercalated by a solventcasting method using chloroform as a co-solvent to produce nanocomposite. The d spacings of both BAP and BAP/ OMMT were examined by X-ray diffraction analysis and the microstructure of BAP/OMMT was examined by TEM.

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Nanocomposites of poly(epsilon-caprolactone) and modified montmorillonite, containing 0-44 wt% clay, were prepared by intercalating the monomer in the modified clay followed by ring-opening polymerisation. Exfoliation of the clay layers was detected by X-ray diffraction in nanocomposites containing up to 16 wt% clay. The presence of the clay did not stop crystallisation, but it did occur to a lesser degree. The permeation of water and difluoromethane vapours was studied. Dual sorption behaviour was observed, attributed to different sorption mechanisms. The permeability decreased with increasing clay content. 18 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; ITALY; WESTERN EUROPE

Accession no.853274 Item 155 Journal of Polymer Science: Polymer Chemistry Edition 40, No.10, 15th May 2002, p.1498-503 SILICON-METHOXIDE-MODIFIED CLAYS AND THEIR POLYSTYRENE NANOCOMPOSITES Zhu J; Start P; Mauritz K A; Wilkie C A Marquette,University; Southern Mississippi,University Clays, organically modified by reaction with ammonium salts containing a silicon methoxide linkage, were dispersed with AIBN in styrene and heated to 60 C to obtain polystyrene-clay nanocomposites. The nanocomposites were characterised by X-ray diffraction, and transmission electron and atomic force microscopies. Thermal stability and flame retardance were determined by thermogravimetric analysis and cone calorimetry. It is proposed that the linkage which occurred between the

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References and Abstracts

silicon and the clay did not occur in the nanocomposite as the distance between the reactive sites was increased by the polystyrene. 18 refs. USA

Accession no.853231 Item 156 Fire & Materials 25, No.5, Sept./Oct.2001, p.193-7 FLAME RETARDANT PROPERTIES OF EVANANOCOMPOSITES AND IMPROVEMENTS BY COMBINATION OF NANOFILLERS WITH ALUMINIUM TRIHYDRATE Beyer G Kabelwerk Eupen AG Flame retardant nanocomposites are synthesised by meltblending EVA with modified layered silicates (montmorillonites). Thermogravimetric analysis performed under different atmospheres (nitrogen and air) demonstrates a clear increase in the thermal stability of the layered silicate-based nanocomposites. Use of cone calorimetry to investigate the fire properties of the materials indicates that the nanocomposites cause a large decrease in heat release. Char formation is the main factor important for improvement and its function is outlined. Further improvements in flame retardancy by combinations of nanofillers and traditional FR additives on the basis of metal hydroxides are also studied. 15 refs. BELGIUM; EUROPEAN COMMUNITY; EUROPEAN UNION; WESTERN EUROPE

Accession no.852891

Item 158 Macromolecules 35, No.6, 12th March 2002, p.2042-9 INFLUENCE OF CRYSTALLIZATION ON INTERCALATION, MORPHOLOGY, AND MECHANICAL PROPERTIES OF POLYPROPYLENE/CLAY NANOCOMPOSITES Maiti P; Pham Hoai Nam; Okamoto M; Hasegawa N; Usuki A Toyota Technological Institute; Toyota Central R & D Laboratories Inc. Intercalated PP/clay nanocomposites were prepared by a melt extrusion process using maleic anhydride-modified PP (PP-MA) and organophilic clay (montmorillonite intercalated with stearylammonium ion). The intercalation of PP-MA chains in the space between silicate galleries increased with the crystallisation temperature and decreased with increasing clay content. Compared with matrix PP-MA, the dispersed clay particles in the PPMA matrix acted as nucleating agents and lowered the spherulite dimensions with increasing clay content. PP/ clay nanocomposites crystallised at high crystallisation temperatures showed some segregation of the dispersed clay particles around the boundary of the spherulites. Extensive intercalation occurred during crystallisation, especially at high crystallisation temperatures. The degree of intercalation of the PP-MA chains in the silicate galleries depended strongly on the time in the molten state. By controlling the intercalation by crystallising at a suitable temperature, the fine structure, morphology and mechanical properties of the nanocomposites could be controlled. 16 refs. JAPAN

Item 157 Macromolecules 35, No.6, 12th March 2002, p.2375-9 X-RAY CHARACTERIZATIONS OF POLYETHYLENE POLYHEDRAL OLIGOMERIC SILSESQUIOXANE COPOLYMERS Lei Zheng; Waddon A J; Farris R J; Coughlin E B Massachusetts,University PE-co-polyhedral oligomeric silsesquioxane (POSS) random copolymers were characterised using wide angle X-ray scattering. Crystallites of both PE and pendant POSS nanoparticles were found to coexist in the copolymers, leading to a “mutually dependant” microstructure in which neither component could be said to be controlling. POSS crystallised as anisotropically shaped crystallites. The presence of POSS disrupted the crystallisation of PE, resulting in less and smaller/ disordered PE crystallites. POSS nanocrystals were covalently connected to the PE crystallites and they reinforced the PE crystallites. The PE crystallites maintained their crystalline structure under high draw ratio. 27 refs. USA

Accession no.852210

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Accession no.852173 Item 159 Journal of Polymer Science: Polymer Chemistry Edition 40, No.7, 1st April 2002, p.885-91 SYNTHESIS AND THERMAL PROPERTIES OF HYBRID COPOLYMERS OF SYNDIOTACTIC POLYSTYRENE AND POLYHEDRAL OLIGOMERIC SILSESQUIOXANE Lei Zheng; Kasi R M; Farris R J; Coughlin E B Massachusetts,University Novel random copolymers of syndiotactic PS and polyhedral oligomeric silsesquioxane (POSS) were synthesised by the copolymerisation of styrene and a POSS-styryl macromonomer, using cyclopentadienyltitanium trichloride and methylaluminoxane. NMR studies showed a moderately high syndiotacticity of the PS backbone which was consistent with the catalyst used and a POSS loading as high as 24 wt% and 3.2 mol%. Thermogravimetric analysis of the copolymers under both nitrogen and air showed improved thermal stability with higher degradation temperatures and char yields, which showed that the incorporation of the inorganic POSS

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nanoparticles made the organic polymer matrix more thermally robust. 23 refs.

the superior tensile properties and lower biodegradability. 16 refs.

USA

CHINA; KOREA

Accession no.852134

Accession no.851424

Item 160 Journal of Polymer Science: Polymer Physics Edition 40, No.8, 15th April 2002, p.736-46 POLYMORPHIC BEHAVIOR IN SYNDIOTACTIC POLYSTYRENE/CLAY NANOCOMPOSITES Tzong-Ming Wu; Sung-Fu Hsu; Jeng-Yue Wu Taiwan,National Chung-Hsing University

Item 162 Polymer 43, No.8, 2002, p.2445-9 FT-IR SPECTROSCOPIC STUDY OF HYDROGEN BONDING IN PA6/CLAY NANOCOMPOSITES Qiuju Wu; Xiaohui Liu; Berglund L A Lulea,University of Technology

Syndiotactic PS(sPS)/clay nanocomposites were prepared by intercalation of sPS into layered montmorillonite. Both X-ray diffraction data and TEM micrographs of the nanocomposites indicated that most of the swellable silicate layers were exfoliated and randomly dispersed in the sPS matrix. The X-ray diffraction data also showed the presence of polymorphism in the sPS/clay nanocomposites. This polymorphic behaviour was strongly dependent on the thermal history of the nanocomposites from the melt and on the content of clay in the composites. Quenching from the melt induced crystallisation into the alpha-crystalline form and the addition of montmorillonite probably increased heterophase nucleation of the alpha-crystalline form. The effect of the melt crystallisation of sPS and sPS/clay nanocomposites at different temps. on the crystalline phases was also examined. 34 refs.

Fourier transform infrared spectroscopy was used to study polyamide-6/clay nanocomposites which had been cooled from the melt at different rates. Compared with the pure polymer, the presence of the clay silicate layers enhanced the formation of the gamma-crystalline phase, the effect being greater at faster cooling rates. This phenomenon is explained in terms of hydrogen bonding. It is proposed that the gamma-phase is most likely to be concentrated in regions close to the silicate layers, with alpha-phase formation being favoured in the bulk polymer. 45 refs.

TAIWAN

Accession no.851529 Item 161 Polymer 43, No.8, 2002, p.2495-500 MICROSTRUCTURE, TENSILE PROPERTIES, AND BIODEGRADABILITY OF ALIPHATIC POLYESTER/CLAY NANOCOMPOSITES Sang-Rock Lee; Hwan-Man Park; Hyuntaek Lim; Taekyu Kang; Xiucuo Li; Won-Jei Cho; Chang-Sik Ha Pusan,National University; Hebei,University of Technology Nanocomposites were prepared by melt intercalating a biodegradable aliphatic polyester with organoclays to enhance its tensile properties. Commercially available materials were used, the organoclays being modified montmorillonites, with different ammonium cations located in the silicate gallery, whilst the polyester was a copolymer prepared by polycondensation of aliphatic glycols (ethylene glycol and 1,4-butanediol) and aliphatic dicarboxylic acids (succinic and adipic acids). The dispersion of the silicate layers was studied using X-ray diffraction and transmission electron microscopy. The nanocomposites exhibiting the higher degree of intercalation, attributed to strong hydrogen bonding, had

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EUROPEAN UNION; SCANDINAVIA; SWEDEN; WESTERN EUROPE

Accession no.851419 Item 163 Polymer 43, No.8, 2002, p.2185-9 PREPARATION AND PROPERTIES OF EPDMCLAY HYBRIDS Usuki A; Tukigase A; Kato M Toyota Central R & D Laboratories Inc. Ethylene-propylene-diene terpolymer (EPDM)-exfoliated clay hybrids were prepared by melt blending EPDM with organophilic montmorillonite. Following additions of various accelerators, the EPDM was press moulded at 160 C to form sheets. Hybrids were successfully prepared when using thiuram and dithiocarbamate compounds as accelerators. The hybrid containing 4 wt% clay had a tensile strength twice that of neat EPDM at 25 C. The storage moduli of the hybrid were also higher, whilst the gas permeability was decreased by 30%. 21 refs. JAPAN

Accession no.851389 Item 164 Polymer 43, No.8, 2002, p.2123-32 POLYETHYLENE-LAYERED SILICATE NANOCOMPOSITES PREPARED BY THE POLYMERIZATION-FILLING TECHNIQUE: SYNTHESIS AND MECHANICAL PROPERTIES Alexandre M; Dubois P; Sun T; Garces J M; Jerome R

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References and Abstracts

Liege,University; Dow Chemical Co. Montmorillonite and hectorite were treated with trimethylaluminium-depleted methylaluminoxane, a Tibased constraint geometry catalyst attached to their surfaces, and ethylene polymerised in-situ to form nanocomposites. Ultra-high molecular weight polyethylene (PE) was produced in the absence of a chain transfer agent. The nanocomposites exhibited poor tensile properties, which were independent of the nature and content of the silicate. Hydrogen additions during polymerisation decreased the PE molecular weight and enhanced the tensile and shear moduli. Exfoliation of the layered silicates was studied using X-ray diffraction and transmission electron microscopy. 29 refs. BELGIUM; EUROPEAN COMMUNITY; EUROPEAN UNION; USA; WESTERN EUROPE

Accession no.851382 Item 165 Macromolecules 35, No.8, 9th April 2002, p.3104-10 NEW POLYLACTIDE/LAYERED SILICATE NANOCOMPOSITES. I. PREPARATION, CHARACTERIZATION AND PROPERTIES Ray S S; Maiti P; Okamoto M; Yamada K; Ueda K Toyota Technological Institute; Unitika Ltd. New polylactide/layered silicate nanocomposites were prepared by melt extrusion of polylactide and montmorillonite. Morphologies were examined using TEM. The effect of oligocaprolactone compatibiliser in the nanocomposites was investigated using morphological analysis and mechanical property measurements. 33 refs. JAPAN

Accession no.851164 Item 166 Synthetic Metals 128, No.1, 10th April 2002, p.115-20 POLYANILINE-DBSA/ORGANOPHILIC CLAY NANOCOMPOSITES: SYNTHESIS AND CHARACTERIZATION Jia W; Segal E; Kornemandel D; Lamhot Y; Narkis M; Siegmann A Technion-Israel Institute of Technology The polymerisation of anilinium-dodecylbenzenesulphonic acid(DBSA) monomer in an aqueous medium in the presence of an organically modified montmorillonite(MMT) clay (a special grade for nylon) resulted in the formation of nanocomposites. The polymerisation and conductivity behaviour of the nanocomposites were studied. The intercalation of polyaniline-DBSA into the galleries of the organoclay was confirmed by X-ray diffraction analysis and significantly large d-spacing expansions from 13.3 to 29.6A for the nanocomposites prepared at different conditions were observed. For comparison, a polyaniline-DBSA/untreated

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MMT composite was also studied. X-ray results for the latter showed that no intercalation had taken place. TGA demonstrated enhancement of the thermal stability of the nanocomposites relative to the bulk polymers. 22 refs. ISRAEL

Accession no.850480 Item 167 Macromolecular Rapid Communications 23, No.3, 19th Feb.2002, p.191-5 SYNTHESIS AND RHEOLOGY OF INTERCALATED POLYSTYRENE/NA+MONTMORILLONITE NANOCOMPOSITES Kim T H; Jang L W; Lee D C; Choi H J; Jhon M S Inha,University; Carnegie-Mellon University PS/clay nanocomposites were synthesised by emulsion polymerisation of styrene in the presence of sodium ionexchanged montmorillonite(Na+-MMT) and it was shown that the strongly hydrophobic PS was intercalated into the hydrophilic silicate layers. The nanocomposites were examined by means of X-ray diffraction, TEM and TGA. The rheological properties of the PS/Na+-MMT nanocomposites were also studied and more marked shear thinning behaviour was observed with increasing clay content. 47 refs. KOREA; USA

Accession no.848619 Item 168 Polymer Degradation and Stability 75, No.3, 2002, p.555-60 THERMAL DEGRADATION BEHAVIOR OF POLYANILINE IN POLYANILINE/NA+MONTMORILLONITE NANOCOMPOSITES Dongkyu Lee; Kookheon Char Seoul,National University The thermal degradation behaviour of polyaniline(PANI) in PANI/sodium montmorillonite(Na+-MMT) nanocomposites prepared by in-situ intercalative polymerisation of aniline into Na+-MMT was investigated by TGA and X-ray diffraction(XRD). The residual weight and its weight derivative of the nanocomposites suggested that the PANI chains for PANI/Na+-MMT nanocomposites were more thermally stable than those for a simple PANI/Na+-MMT mixture. This improvement in the thermal stability for the nanocomposites was attributed to the presence of Na+-MMT nanolayers with a high aspect ratio acting as barriers, thus shielding the degradation of PANI in the nanogalleries and also hindering the diffusion of degraded PANI from the nanocomposites. The shielding effect of the nanolayers was found to be significant as the Na+-MMT content in the PANI/Na+-MMT nanocomposites was increased. The XRD patterns of the nanocomposites after TGA measurements indicated that the basal spacing of the PANI/Na+-MMT nanocomposites was almost intact,

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indicating that the thermal decomposition of the PANI chains occurred mainly outside the silicate layers. 51 refs.

composition on the molecular barrier, optical clarity and thermal stability were studied and discussed. 16 refs.

SOUTH KOREA

TAIWAN

Accession no.848541

Accession no.848144

Item 169 Chemistry of Materials 14, No.1, Jan.2002, p.189-93 FIRE RETARDANT HALOGEN-ANTIMONYCLAY SYNERGISM IN POLYPROPYLENE LAYERED SILICATE NANOCOMPOSITES Zanetti M; Camino G; Canavese D; Morgan A B; Lamelas F J; Wilkie C A Torino,Universita; US,National Inst.of Standards & Technology; Marquette,University

Item 171 Polymer Preprints. Volume 42. No.2. Fall 2001. Proceedings of a conference held Chicago, Il., 26th30th August 2001. Washington, D.C., ACS,Div.of Polymer Chemistry, 2001, p.99-100 MODIFIED BIOMEDICAL POLYURETHANE BLOCK COPOLYMERS: NANOCOMPOSITES AND POLYISOBUTYLENE COMB POLYMERS Runt J; Weisherg D M; Xu R; Garrett J T; Manias E; Renesi A; Gordon B; Snyder A J; Rosonberg G Pennsylvania,State University; Polymer Chemistry Innovations Inc. (ACS,Div.of Polymer Chemistry)

The flammability of nanocomposites of PP-graft-maleic anhydride with organically modified clays was studied with and without the presence of both decabromodiphenyl oxide and antimony trioxide fire retardants. The combustion behaviour was evaluated using oxygen consumption cone calorimetry. Synergy was observed between the nanocomposite and the fire retardants, which did not occur when antimony oxide and the brominated fire retardant were added to the virgin polymer. 28 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; ITALY; USA; WESTERN EUROPE

Accession no.848147 Item 170 Chemistry of Materials 14, No.1, Jan.2002, p.154-61 ANTICORROSIVELY ENHANCED PMMA-CLAY NANOCOMPOSITE MATERIALS WITH QUATERNARY ALKYLPHOSPHONIUM SALT AS AN INTERCALATING AGENT Jui-Ming Yeh; Shir-Joe Liou; Ching-Yi Lin; Chiao-Yu Cheng; Ya-Wen Chang; Kueir-Rarn Lee Chung-Yuan Christian University; Nanya,Institute of Technology PMMA-layered montmorillonite (MMT) clay nanocomposite materials were prepared by dispersing the MMT clay nanolayers in the PMMA matrix by in-situ thermal polymerisation. The organophilic clay was prepared by a cation exchange reaction between the sodium cations of MMT clay and the alkylphosphonium cations of the intercalating agent. Methyl methacrylate monomers were first intercalated into the interlayer regions of organophilic clay hosts, followed by free radical polymerisation. Nanocomposite coatings with a low clay loading (such as 1 wt%) on cold-rolled steel gave superior corrosion resistance to coatings of bulk PMMA on the basis of electrochemical measurements of corrosion potential, polarisation resistance, corrosion current and impedance spectroscopy in 5 wt% aqueous sodium chloride electrolyte. A further increase in the clay loading slightly enhanced the molecular barrier property of the nanocomposite materials. The effects of the material

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Polyurethane urea multiblock copolymers (PUU) are used in a range of biomedical applications, including bloodcontact components in ventricular assist systems. One of the drawbacks of these materials is their relatively high permeability to air and moisture. Conventional biomedical PUU elastomers are generally composed of ~80 wt.% soft segment, most often polytetramethylene oxide. It is penetrant diffusion through the continuous, low Tg polyether phase that gives rise to the high permeability. One approach to resolving this problem is to synthesise a polymer architecture that has backbone chemistry nearly identical to a typical biomedical PUU, and possesses polymeric combs of a material with superior barrier properties. The PUU backbone would render the comb polymer ‘compatible’ with existing PUU multiblock copolymers, while the combs, anticipated to microphase separate, are expected to reduce the transport of air and water vapour. Polyisobutylene is chosen for the combs due to the combination of its good barrier properties and its controllable (living cationic) polymerisation. A second approach involves dispersing organically-modified layered silicates (OMS) in typical biomedical PUUs. As a result of their high aspect ratio, the introduction of modest amounts of intercalated or exfoliated OMS inorganic layers in PUUs can dramatically enhance barrier properties. The synthesis and characterisation of a series of polymers with backbones chemically identical to the multiblock PUU, but which also possess polymeric combs of a material with superior barrier properties, are described. The concurrent property enhancements are well beyond what can be generally achieved through chemical modification of PUU polymers. 5 refs. USA

Accession no.847991 Item 172 Polymer Preprints. Volume 42. Number 2. Fall 2001. Proceedings of a conference held Chicago, Il., 26th30th August 2002.

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References and Abstracts

Washington, D.C., ACS,Div.of Polymer Chemistry, 2001, p.61-2 HIGH TEMPERATURE ORGANIC/INORGANIC NANOCOMPOSITES FROM CUBIC SILSESQUIOXANES Laine R M; Choi J; Tamaki R; Kim S G Michigan,University (ACS,Div.of Polymer Chemistry) It was recently suggested that it is possible to develop detailed structure-property-processing relationships in hybrid nanocomposites through use of octa-functionalised silsesquioxanes. In this approach, synthetic routes to cube macromonomers were developed that allow tailoring of the nanoarchitecture of the organic phase between SiO hard inorganic cores. In this way it has been possible, in a preliminary fashion, to develop materials that exhibit quite different mechanical properties based on small changes in the chemical make-up of the organic phase. Work to date has been with octaglycidyl epoxide functionalised cubes that have chains that limit their high temperature utility. Functionalised aromatic silsesquioxanes have now been produced. The potential of making nanocomposite materials with octaaminophenyl cubes is explored. In these studies, the ratio of epoxide groups to amine groups is varied such that the amine is less than stoichiometric to two times stoichiometric. 4 refs. USA

Accession no.847971 Item 173 Polymer Preprints. Volume 42. Number 2. Fall 2001. Proceedings of a conference held Chicago, Il., 26th30th August 2002. Washington, D.C., ACS,Div.of Polymer Chemistry, 2001, p.48-9 POSS NANOSTRUCTURED CHEMICALS: TRUE MULTIFUNCTIONAL POLYMER ADDITIVES Schwab J J; Reinerth W A; Lichtenhan J D; An Y-Z; Phillips S H; Lee A Hybrid Plastics; US,Edwards Air Force Base; Michigan,State University (ACS,Div.of Polymer Chemistry) Continuing demand for advancements in the performance of polymeric materials has driven the search for new additive technologies to upgrade the properties of existing plastics. One of the primary goals has been to reinforce polymeric chains and segments at the molecular level in much the same way that traditional fillers reinforce plastics on the macroscopic level. This would prevent polymers and their corresponding composites from being subject to thermal limitations imposed by coil-coil and segment-segment interactions. Significant opportunity exists for new additive technologies that are compatible with existing polymer/filler systems yet provide unique value that is not attained from conventional technological approaches. Nanostructured Chemicals represent a merger

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between chemical and filler technologies acting as true multifunctional polymer additives. The chemical diversity of POSS Nanostructured Chemicals is vast and parallels that of traditional organic systems, yet incorporates it onto a robust and precisely defined inorganic (silicon-oxygen) nanostructure. POSS Molecular Silicas can be utilised in the same manner as traditional polymer additives in both melt and solution compounding. Molecular Silicas are capable of alloying polymer chains at the molecular level to improve the physical properties of virtually all plastics. Loading levels for Molecular Silicas can be varied in accordance to the degree and level of enhancement desired. POSS Nanostructured Chemicals have the unique ability to act as multifunctional polymer additives by simultaneously acting as molecular level reinforcements, processing aids and flame retardants. 3 refs. USA

Accession no.847964 Item 174 Chemistry of Materials 14, No.2, Feb.2002, p.486-8 HYPERBRANCHED POLYMER LAYERED SILICATE NANOCOMPOSITES Plummer C J G; Garamszegi L; Leterrier Y; Rodlert M; Manson J A E Lausanne,Ecole Polytechnique Federale Hydroxy-terminated hyperbranched polyesters were processed with sodium montmorillonite using water as a dispersant. The polyesters were prepared by condensation of 2,2-bishydroxymethyl propionic acid with a tetrafunctional ethoxylated pentaerythritol core. Exfoliated composites were obtained at up to 10 wt % montmorillonite and used as precursors for glassy PU nanocomposites. TEM micrographs were obtained of a second pseudo-generation hyperbranched polymer/10 wt % sodium montmorillonite nanocomposite. The stressstrain properties of the composites were investigated and significantly enhanced stiffness enhancement was demonstrated in the presence of exfoliated silicate layers. 20 refs. SWITZERLAND; WESTERN EUROPE

Accession no.847645 Item 175 ACS Polymeric Materials Science and Engineering Fall Meeting.Volume 85. Chicago, IL, 26th-30th August 2001, p.562-3, 012 STUDY OF MOLECULES IN NANO-SCALE CONFINED SPACE BY DSC: NANOCOMPOSITE FORMATION BY ION-DIPOLE INTERACTION Li Y; Ishida H Case Western Reserve University (ACS,Div.of Polymeric Materials Science & Engng.) Differential scanning calorimetry was used to study the intercalation process and the amine interlayer structure

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References and Abstracts

following montmorillonite modification by hexadecylamine. Intercalation was confirmed by wide angle X-ray diffraction. The amine molecules intercalated immediately after melting and recrystallised within the clay layers. The confined amine formed an ordered structure, and had much higher melting temperatures than in the free state. The fine structure was strongly dependent upon the amine:clay ratio, and was further influenced by intercalation of polymer chains. 11 refs. USA

Accession no.847130 Item 176 ACS Polymeric Materials Science and Engineering Fall Meeting.Volume 85. Chicago, IL, 26th-30th August 2001, p.556-7, 012 COMPUTER SIMULATION OF LI+/ POLY(ETHYLENE-OXIDE) IN NANOMETER CONFINEMENTS Kuppa V; Manias E Pennsylvania,State University (ACS,Div.of Polymeric Materials Science & Engng.) Computer simulations showed the structure of the Li+ poly(ethylene oxide) (PEO) system to consist of a noncrystalline PEO bilayer with the Li+ located adjacent to the surfaces. In bulk systems a change in the ion transport mechanism was observed, from hopping motion between PEO crowns at low temperatures, to a random, Brownianlike motion at higher temperatures. When constrained in nano-sized channels (such as in montmorillonite nanocomposites), a hopping mechanism was exhibited at all temperatures, the Li+ moving between the low energy sites on the inorganic surface. 7 refs. USA

Accession no.847127 Item 177 Polymer 43,No.6,2002,p.1933-6 PHASE TRANSITION IN NYLON 6/CLAY NANOCOMPOSITES ON ANNEALING Xiaohui Liu; Qiuju Wu Lulea,University of Technology The gamma to alpha crystalline phase transition in nylon 6/clay nanocomposites prior to melting was investigated by X-ray diffraction. The phase transition in the nanocomposite took place at 160C, 40C higher than that of nylon 6 at 120C. The transition extent in the nanocomposite was lower than that in nylon 6. This could be caused by the strongly confined spaces between layers, and the favourable environment for the formation of the gamma phase in the presence of clay. Also, the less grown crystallites of the alpha phase transformed from the gamma phase in the nanocomposite began to melt at a much lower temperature than its normal melting temperature. 19 refs.

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EU; EUROPEAN COMMUNITY; EUROPEAN UNION; SCANDINAVIA; SWEDEN; WESTERN EUROPE; WESTERN EUROPE-GENERAL

Accession no.846167 Item 178 Chemistry of Materials 13, No.12, Dec.2001, p.4649-54 STUDIES ON THE MECHANISM BY WHICH THE FORMATION OF NANOCOMPOSITES ENHANCED THERMAL STABILITY Jin Zhu; Uhl F M; Morgan A B; Wilkie C A Marquette,University; US,National Inst.of Standards & Technology PS-clay and PS-graphite nanocomposites were prepared and used to explore the process by which the presence of clay or graphite in a nanocomposite enhanced the thermal stability of polymers. The study was designed to determine if the presence of paramagnetic iron in the matrix could result in radical trapping and thus enhance thermal stability. Nanocomposites were prepared by bulk polymerisation, using both iron-containing and irondepleted clays and graphites, and they were characterised by X-ray diffraction, TEM, TGA and cone calorimetry. The presence of structural iron, rather than that present as an impurity, significantly increased the onset temp. of thermal degradation in polymer-clay nanocomposites. Intercalated nanocomposites showed an iron effect, but this was less important for exfoliated systems. Polymergraphite nanocomposites showed no difference between iron-free and iron-containing nanocomposites, presumably because the iron was not nanodispersed in the graphite. 14 refs. USA

Accession no.846048 Item 179 Macromolecular Rapid Communications 22, No.17, 11th Dec.2001, p.1438-40 UNUSUAL CRYSTALLIZATION BEHAVIOR IN POLYAMIDE 6/MONTMORILLONITE NANOCOMPOSITES Qiuju Wu; Xiaohui Liu; Berglund L A Lulea,University of Technology The crystallisation behaviour and structure of polyamide6 nanocomposites containing 3 wt % montmorillonite(MMT) were studied by DSC and X-ray diffraction for different cooling conditions. In contrast to pure polyamide-6 and other semicrystalline polymers, increased cooling rates resulted in higher crystallinity of the composite. The highest crystallinity (60.8%) was observed for a liquid nitrogen-quenched polyamide-6/ MMT film. The gamma-crystalline form was predominant in rapidly cooled composites. 14 refs. EUROPEAN UNION; SCANDINAVIA; SWEDEN; WESTERN EUROPE

Accession no.846013

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References and Abstracts

Item 180 Journal of Applied Polymer Science 83, No.9, 28th Feb.2002, p.1978-85 CRYSTALLIZATION BEHAVIORS OF POLYPROPYLENE/MONTMORILLONITE NANOCOMPOSITES Jisheng Ma; Shimin Zhang; Zongneng Qi; Ge Li; Youliang Hu Chinese Academy of Sciences The isothermal crystallisation kinetics of PP/montmorillonite composites synthesised via intercalation polymerisation were studied using DSC and polarised optical microscopy. The crystallinity of the nanocomposites decreased with increasing montmorillonite content, indicating that the montmorillonite layers dispersed in the PP matrices confined the PP chains, thereby hindering their crystallisation. However, the montmorillonite layers acted as heterogeneous nuclei in the nucleation of crystallisation, causing a dramatic increase in crystallisation state and decrease of the spherulite size with increasing montmorillonite content. The nucleus density increased with increasing motmorillonite content, leading to a positive effect on the crystallisation. 16 refs. CHINA

Accession no.845562 Item 181 Advanced Materials 14, No.2, 16th Jan. 2002, p.128-30 HIGH-PERFORMANCE POLYPROPYLENECLAY NANOCOMPOSITES BY IN-SITU POLYMERISATION WITH METALLOCENE/ CLAY CATALYSTS Sun T; Garces J M Dow Chemical Co. The development of a procedure for making highperformance PP nanocomposites by in-situ polymerisation under mild polymerisation conditions is reported. These composites exhibit reduced thermal expansion coefficients, improved melt flow strengths, lower gas diffusion coefficients and increased heat distortion temperatures and are considered to have potential as replacements for engineering plastics. USA

Accession no.845220 Item 182 Polymer Degradation and Stability 74, No.3, 2001, p.413-7 COMBUSTION BEHAVIOUR OF EVA/ FLUOROHECTORITE NANOCOMPOSITES Zanetti M; Camino G; Mulhaupt R Torino,Universita; Freiburger Materialforschungszentrum The flammability properties of composites based on ethylene vinyl acetate copolymer (EVAc) and fluorohectorite exchanged with either octadecyl-

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ammonium (ODA) or aminododecanoic acid (ADA) are investigated. The product with ODA is a true nanocomposite. The weight loss behaviour in combustion is found to be similar to that in thermal decomposition. A delayed heat release results from delayed evolution of degradation products combined with the barrier effect of dispersed nanolayers. The ADA composite showed no exfoliation and appears to be a conventional filled polymer. The weight loss in combustion of the ADA composite is accelerated compared to thermal degradation. Accumulation of silicate on the surface of the burning specimen provides some barrier effects although it is less effective than the ODA nanocomposite. Dripping of burning particles in vertical combustion is suppressed only in the case of the nanocomposite which reduces the hazard of fire spread to surrounding flammable materials. 13 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; ITALY; WESTERN EUROPE

Accession no.844096 Item 183 Macromolecules 34, No.25, 4th Dec.2001, p.8686-93 VISCOELASTIC AND MECHANICAL PROPERTIES OF EPOXY/MULTIFUNCTIONAL POLYHEDRAL OLIGOMERIC SILSESQUIOXANE NANOCOMPOSITES AND EPOXY/LADDERLIKE POLYPHENYLSILSESQUIOXANE BLENDS Gui Zhi Li; Lichang Wang; Toghiani H; Daulton T L; Koyama K; Pittman C U Mississippi,State University; Mississippi,Stennis Space Center; Yamagata,University Aliphatic epoxy/multifunctional polyhedral oligomeric silsesquioxane (POSS) nanocomposites (epoxy/POSS 95/5 and 75/25) and epoxy blends with the prepolymer of ladder-like polyphenylsilsesquioxane (PPSQ) (epoxy/ PPSQ 95/5, 90/10 and 85/15) were prepared by solution casting and curing. The POSS units incorporated into the epoxy network were well-dispersed in the composite, even at high POSS content (25 wt%). The epoxy/PPSQ blends showed good miscibility only at low PPSQ content (up to 10 wt%). Incorporating POSS into the epoxy network by curing at upper temperatures of 120 and 150C broadened the temperature range of the glass transition of the composites but had almost no effect on their glass transition temperature. The glass transition temperature of epoxy/PPSQ blends containing up to 10 wt% PPSQ increased slightly with increasing PPSQ content but that of blends containing 15 wt% PPSQ was lower than that of the neat epoxy resin because the crosslink density was reduced in the blend. PPSQ had no effect on the width of the glass transition range of the blends. The storage moduli of both the composites and the blends above the glass transition temperature were higher than those of neat epoxy resin and increased

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with POSS or PPSQ content, improving their thermal dimensional stability. POSS or PPSQ increased the flexural modulus and hardness of the epoxy resins. However, the flexural strengths of both epoxy/POSS composites and epoxy/PPSQ blends were lower than that of neat epoxy. 22 refs. JAPAN; USA

Accession no.842675 Item 184 Polymer 43, No.3, 2002, p.1017-20 POLYMER/LAYERED CLAY NANOCOMPOSITES: 2. POLYURETHANE NANOCOMPOSITES Yao K J; Song M; Hourston D J; Luo D Z Loughborough,University; Hyperlast Ltd.

polyimide/clay nanocomposite films showed higher room temperature tensile moduli and lower strength and elongation to break than the control films. 38 refs. USA

Accession no.842631 Item 186 Plastics and Rubber Weekly 1st Feb.2002, p.2 KABELWERK EUPEN LAUNCHES NANOCOMPOSITE APPLICATION Beevers A

PU/Na montmorillonite nanocomposites were synthesised from modified MDI, modified polyether polyol and Na montmorillonite. The strength and strain at break increased with increasing amounts of layered clay. The storage modulus below the glass transition temperature of the soft segments in the PU was increased by more than 350%. The thermal conductivity decreased slightly with increased layered clay loading. 8 refs.

Belgian cable and pipe producer Kabelwerk Eupen has unveiled a commercial application for polymer-clay nanocomposites. It is using the materials to produce flame-retardant cables. The firm manufactures EVA-based nanocomposites using its “one-pot synthesis” extrusion technology. The addition of 5% nanoclay improves the fire performance of EVA by promoting char formation and delaying degradation. Importantly, it prevents dripping of burning polymer. Kabelwerk Eupen has also investigated the combination of nanocomposites with other flame retardants. These include incorporating alumina trihydrate into EVA to improve the resistance of cables to fire. KABELWERK EUPEN AG

EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

BELGIUM; EUROPEAN COMMUNITY; EUROPEAN UNION; WESTERN EUROPE

Accession no.842654

Accession no.842398

Item 185 Polymer 43, No.3, 2002, p.813-22 PREPARATION AND CHARACTERIZATION OF POLYIMIDE/ORGANOCLAY NANOCOMPOSITES Delozier D M; Orwoll R A; Cahoon J F; Johnston N J; Smith J G; Connell J W Williamsburg,College of William & Mary; NASA Langley Research Center

Item 187 Progress in Colloid & Polymer Science Vol.117, 2001, p.120-5 POLYPROPYLENE/MONTMORILLONITE NANOCOMPOSITES PREPARED BY THE DELAMINATION OF THE FILLER Pozsgay A; Papp L; Frater T; Pukanszky B Budapest,University of Technology & Economics; Hungarian Academy of Sciences

Several approaches were used to prepare welldispersed, fully exfoliated polyimide/organoclay nanocomposites, in which the modified montmorillonite clay contained a long chain aliphatic quaternary ammonium cation. The best results were obtained using in-situ polymerisation whereby poly(amic acid)s were synthesised in the presence of the organoclay. Thermal conversion of the resulting poly(amide acid)/organoclay films in either air or nitrogen produced the corresponding polyimide films, which were visually darker than control films without clay. This was because decomposition of the organic cation occurred, resulting in a degree of collapse of the clay particles into larger agglomerates. The degradation was less pronounced when the thermal treatment was carried out under nitrogen. The

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PP/montmorillonite (PP/MMT) nanocomposites are prepared by the exfoliation of the nanoclay during processing. The filler is used in various forms (sieved bentonite, sodium and organophilic MMT) in order to determine the effect of subsequent stages of organoclay preparation on the structure and properties of the composite. The filler content is varied over a relatively wide range to determine the extent of maximum reinforcement and the range of practically relevant compositions. Specimens are injection moulded with various weak sites (weld lines, gate section) in the test area to see the performance of the nanocomposite under practically relevant conditions. The results prove that extensive exfoliation of the organophilic MMT occurs during homogenisation and subsequent injection moulding of the PP composites studied; however, organophilisation of NaMMT is not complete, which

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References and Abstracts

hinders the perfect exfoliation of the MMT layers. Sieved bentonite and NaMMT behave like traditional fillers, while the incorporation of the organoclay into PP yields a true nanocomposite. Because of incomplete exfoliation and poor adhesion, only a moderate improvement of mechanical properties is achieved. Reinforcement depends on composition; above a certain filler content, the nanoclay behaves like a particulate filler, possibly due to the stacking of exfoliated layers. The weld line strength of PP nanocomposites is very low; exfoliated clay particles orientate parallel to the weld line and strongly deteriorate the properties. 19 refs. EASTERN EUROPE; HUNGARY

Accession no.842186 Item 188 Journal of Polymer Science: Polymer Physics Edition 39, No.22, 15th Nov.2001, p.2727-39 CRYSTALLISATION STUDIES OF ISOTACTIC POLYPROPYLENE CONTAINING NANOSTRUCTURED POLYHEDRAL OLIGOMERIC SILSESQUIOXANE MOLECULES UNDER QUIESCENT AND SHEAR CONDITIONS Fu B X; Yang L; Somani R H; Zong S X; Hsiao B S; Phillips S; Banski R; Ruth P Stony Brook,State University; US,Air Force Research Laboratory Crystallisation studies at quiescent and shear states in isotactic PP (iPP) containing nanostructured polyhedral oligomeric silsesquioxane (POSS) molecules are performed with in situ small-angle X-ray scattering (SAXS) and differential scanning calorimetry (DSC). DSC is used to characterise the quiescent crystallisation behaviour. It is observed that the addition of POSS molecules increases the crystallisation rate of iPP under both isothermal and nonisothermal conditions, which suggests that POSS crystals act as nucleating agents. Furthermore, the crystallisation rate is significantly reduced at a POSS concentration of 30 wt.% which suggests a retarded growth mechanism due to the molecular dispersion of POSS in the matrix. In situ SAXS is used to study the behaviour of shear-induced crystallisation at temperatures of 140, 145 and 150 deg.C in samples with POSS concentrations of 10, 20 and 30 wt.%. It is postulated that although POSS crystals have a limited role in shear-induced crystallisation, molecularly dispersed POSS molecules behave as weak crosslinkers in polymer melts and increase the relaxation time of iPP chains after shear. Therefore, the overall orientation of the polymer chains is improved and a faster crystallisation rate is obtained with the addition of POSS. Moreover, higher POSS concentrations result in faster crystallisation rates during shear. The addition of POSS decreases the average long-period value of crystallised iPP after shear, which indicates that iPP nuclei are probably initiated in

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large numbers near molecularly dispersed POSS molecules. 34 refs. USA

Accession no.842161 Item 189 Journal of Applied Polymer Science 82, No.13, 20th Dec.2001, p.3215-22 PREPARATION AND CHARACTERISATION OF POLYVINYL ALCOHOL-BASED MAGNETIC NANOCOMPOSITES. I. THERMAL AND MECHANICAL PROPERTIES Lopez D; Cendoya I; Torres F; Tejada J; Mijangos C CSIC; Barcelona,University CoFe2O4 magnetic nanoparticles are prepared by in situ precipitation and oxidation of Co2+ and Fe2+ within a sulphonated PS resin. The nanometric particles are characterised by X-ray diffraction. A ferrofluid is prepared from the CoFe2O4 mineralised polymer resin and water. Polyvinyl alcohol (PVA)-based nanocomposite materials are obtained by mixing different amounts of ferrofluid (compositions ranging within 0-51 wt.% of mineralised resin) with an aqueous solution of the polymer. The PVA composite materials are characterised by TGA, DSC and stress-strain testing. The thermal and mechanical properties of PVA change with filler content, exhibiting an initial increase in these properties due to polymer-filler interactions. After a maximum value, at about 15 wt.% of mineralised resin, the mechanical properties decrease probably due to particle aggregation which causes phase separation. The results obtained show that the nanoparticles are dispersed in the amorphous regions of the polymer, the crystalline zones remaining unaltered up to compositions as high as 30 wt.%. 36 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; SPAIN; WESTERN EUROPE

Accession no.842144 Item 190 Polymer Science Series A 43, No.11, Nov. 2001, p.1171-6 SYNTHESIS, STRUCTURE, AND PROPERTIES OF METAL-POLYMER NANOCOMPOSITES BASED ON SILVER AND POLYXYLYLENE Ozerin S A; Zavyalov S A; Chvalun S N Russian Academy of Sciences Details are given of the preparation of nanocomposites with a controllable high concentration of silver nanoparticles organised in a polyxylylene matrix. The structure of the nanocomposites was examined using wide-angle X-ray diffraction. Nanocomposites possessing hopping conductivity were found to display sensor properties toward moisture. 30 refs. RUSSIA

Accession no.842024

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Item 191 Polymer Science Series A 43, No.11, Nov. 2001, p.1163-70 NANOCOMPOSITES BASED ON POLYCARBONATE AND ULTRAFINE DIAMONDS Korobko A P; Krasheninnikov S V; Levakova I V; Ozerina L A; Chvalun S N Moscow,Karpov Institute of Physical Chemistry Polymeric nanocomposites were prepared by direct mixing of ultrafine diamonds with a polycarbonate melt. The structural and mechanical properties of the composites were studied by small-angle X-ray scattering and tensile tests. The mixing process was accompanied by changes in the basic parameter of fractal structure of ultrafine diamond powders and their intense deaggregation. 31 refs. RUSSIA

Accession no.842023 Item 192 Polymer 42, No.10, 2001, p.4501-7 SYNTHESIS AND THERMAL BEHAVIOUR OF LAYERED SILICATE-EVA NANOCOMPOSITES Zanetti M; Camino G; Thomann; Muelhaupt R Turin,University; Freiburger Materialforschungszentrum Extrusion moulding of both polymer-layered silicate nanocomposites and microcomposites based on the copolymer poly(ethylene-co-vinylacetate) with either 12 wt% (EVA 12) or 19 wt% (EVA 19) vinyl acetate content is described. The silicates were a synthetic fluorohectorite, rendered organophilic by means of cation exchange of intergallery sodium cations for octadecylammonium or ammoniumdodecanoic acid, and a montmorillonite, rendered organophilic with octadecylammonium. The materials thus obtained were characterised by wide angle XRD and TEM. It was established that dispersion of the organic phase depends on both the silicate type and silicate modification. At these vinyl acetate contents dispersion was achieved without additional compatibiliser. The thermal behaviour of the composites was examined on a thermobalance in nitrogen and in air. In the nanocomposites acceleration of EVA deacylation and slower thermal degradation were observed, while protection against thermo-oxidation and delayed weight loss were evident in air. 18 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; ITALY; WESTERN EUROPE

Accession no.840997 Item 193 Polymer 42, No.10, 2001, p.4493-9 SYNTHESIS OF EPOXY-CLAY NANOCOMPOSITES. INFLUENCE OF THE NATURE OF THE CURING AGENT ON

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STRUCTURE Kornmann X; Lindberg H; Berglund L A Lulea,University of Technology Epoxy-clay nanocomposites were synthesised by swelling an organophilic montmorillonite in a diglycidyl ether of bisphenol A resin with subsequent polymerisation. Three different curing agents were used: an aliphatic diamine and two cycloaliphatic diamines. The cure kinetics of these systems was evaluated by DSC and the structure of the nanocomposites was characterised by XRD and TEM. Successful nanocomposite synthesis was dependent not only on the cure kinetics of the epoxy system but also on the rate of diffusion of the curing agent into the galleries because it affects the intragallery cure kinetics. The nature of the curing agent greatly affects these two phenomena and therefore the resulting structure of the nanocomposite. The curing temperature controls the balance between the extragallery reaction rate of the epoxy system and the diffusion rate of the curing agent into the galleries. Thus, the choice of curing agent and curing conditions controls the extent of exfoliation of the clay in the material. 10 refs. EUROPEAN UNION; SCANDINAVIA; SWEDEN; WESTERN EUROPE

Accession no.840996 Item 194 Polymer 43, No.2, 2002, p.541-53 PREDICTING THE BINDING ENERGY FOR NYLON 6,6/CLAY NANOCOMPOSITES BY MOLECULAR MODELING Tanaka G; Goettler L A Solutia Inc.; Akron,University The binding energies for nanocomposites consisting of exfoliated clay layers treated with (usually quaternary) ammonium salts dispersed in nylon-6,6 resin were studied using molecular modelling techniques. A model was built, comprising nylon-6,6, a quaternary ammonium ion (quat) and a montmorillonite platelet, on a computer. The system was equilibrated by molecular dynamics and energy minimisation and the binding energies were calculated between all the components i.e. between the nylon-6,6 and the clay platelet, the nylon-6,6 and the quat, and the quat and the clay platelet. The binding energy between the nylon-6,6 and the clay platelet decreased almost linearly with the volume of adsorbed quat. Thus, the pristine clay showed the highest binding strength to the nylon-6,6. Clays which were partly substituted by long quats were equivalent to those which were fully substituted by short quats. 27 refs. USA

Accession no.840814 Item 195 Macromolecules 34, No.23, 6th Nov.2001, p.8084-93

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References and Abstracts

RHEOLOGY OF POLY(ETHYLENE OXIDE)/ ORGANOCLAY NANOCOMPOSITES Hyun Y H; Lim S T; Choi H J; Jhon M S Inha,University; Carnegie-Mellon University

POSS copolymer were maintained at low POSS loadings. A modulus plateau at temps. above 175C was observed, indicating suppression of melt flow for PE POSS copolymers. 40 refs.

A series of PEO/organoclay nanocomposites was prepared by a solvent casting method. Using three different organoclays modified with alkylammonium salts, the effect of surfactants on organoclay surfaces in polymer/ organoclay nanocomposites was investigated with particular reference to internal structure analysis and rheological measurement of the nanocomposites. The d spacings of both the pure PEO and intercalated organoclay were examined via X-ray diffraction analysis and the microstructure of these nanocomposites was examined by TEM. Rheological properties of these nanocomposites exhibited different behaviour with different modifier concentrations and surfactant sizes (chain lengths). In order to analyse the non-Newtonian flow behaviour, shear viscosity data were fitted via the Carreau model, showing that steady shear viscosity and power law behaviour increased with organoclay content. The hysteresis phenomenon was also enhanced with organoclay content and increases in the storage/loss moduli and interactions among organoclay platelets were observed with increasing organoclay content. The enhanced thermal stability of the nanocomposites by organoclay was also observed. 57 refs.

USA

KOREA; USA

Accession no.840225 Item 196 Macromolecules 34, No.23, 6th Nov.2001, p.8034-9 NOVEL POLYOLEFIN NANOCOMPOSITES: SYNTHESIS AND CHARACTERIZATIONS OF METALLOCENE-CATALYZED POLYOLEFIN POLYHEDRAL OLIGOMERIC SILSESQUIOXANE COPOLYMERS Lei Zheng; Farris R J; Coughlin E B Massachusetts,University Ethylene copolymers incorporating a norbornylenesubstituted polyhedral oligomeric silsesquioxane(POSS) macromonomer were prepared using a metallocene/ methylaluminoxane cocatalyst system. Isotactic PPcontaining POSS nanoparticles were also synthesised for the first time using a similar approach utilising a C2 symmetric ansa-metallocene. A wide range of POSS concentrations was obtained in these polyolefin POSS copolymers under mild conditions, up to 56 wt % for PEPOSS copolymers and 73 wt % for PP-POSS copolymers. Preliminary results indicated improved thermooxidative stability for these nanocomposite polyolefins containing the ‘molecular silica’ side groups relative to their homopolymer analogues. TGA of the PE-POSS copolymers under air showed a 90 degree C improvement, relative to a PE control sample of similar molec.wt., in the onset of decomposition temp. based upon 5% mass loss. DMTA showed that the tensile properties of the PE-

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Accession no.840220 Item 197 Polymer Engineering and Science 41, No.11, Nov.2001, p.2036-46 PROCESSING AND PROPERTIES OF POLYMERIC NANO-COMPOSITES Hua Wang; Changchun Zeng; Elkovitch M; Lee L J; Koelling K W Ohio,State University Polymeric nano-composites were prepared by melt intercalation. Nano-clay (montmorillonite) was mixed with either a polymer (nylon-6, PP or PS) or a polymer blend by twin-screw extrusion. The clay-spacing in the composites was measured by X-ray diffraction. The morphology of the composites and its development during the extrusion process were observed by SEM. Melt viscosity and mechanical properties of the composites and the blends were also measured. It was found that the clay spacing in the composites was markedly influenced by the type of polymer used. The addition of the nano-clay could greatly increase the viscosity of the polymer when there was a strong interaction between the polymer and the nano-clay. It could also change the morphology and morphology development of nylon 6/PP blends. The mechanical test showed that the presence of 5 to 10 wt % nano-clay significantly increased the elastic modulus of the composites and blends, while significantly decreasing the impact strength. The water absorption of nylon 6 was decreased in the presence of nano-clay. The effect of nanoclay on polymers and polymer blends was compared with that of kaolin clay under the same experimental conditions. 22 refs. USA

Accession no.840103 Item 198 Polymer Engineering and Science 41, No.11, Nov.2001, p.1963-9 EFFECT OF INTERLAYER STRUCTURE, MATRIX VISCOSITY AND COMPOSITION OF A FUNCTIONALIZED POLYMER ON THE PHASE STRUCTURE OF POLYPROPYLENEMONTMORILLONITE NANOCOMPOSITES Kyu-Nam Kim; Hyungsu Kim; Jae-Wook Lee Dankook,University; Sogang,University PP-clay composites were prepared by melt mixing in an intensive mixer. Three grades of PP with different melt viscosities were used to investigate mixing characteristics and phase structure of the composites with various organically modified montmorillonite(org-MMT) clays.

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Depending on the matrix viscosity and nature of the organic layer in MMT, significant variations in the phase structure of the composites was found. In addition to the simple combination of PP and clay, various functionalised PPs were also incorporated in an attempt to enhance thermodynamic interaction between the org-MMT and PP matrix. Particular attention was paid to the effect of varying thermodynamic affinity between the components on the phase evolution and mechanical properties of the composites. In the available range of maleic anhydride(MA) content in PP, it was found that an optimum content of the functional group existed, which balanced favourable interaction with org-MMT and adequate homogeneity with PP matrix. Together with using the optimum MA content, it was also important to use a low viscosity PP matrix to achieve a more random array of layered silicates. The observed phase structure was interpreted by using a model based on self-consistent field theory. 12 refs. KOREA

Accession no.840096 Item 199 Journal of Polymer Science: Polymer Physics Edition 39, No.21, 1st Nov.2001, p.2581-88 NANOCOMPOSITES OF POLY(ETHYLENE TEREPHTHALATE-CO-ETHYLENE NAPHTHALATE) WITH ORGANOCLAY Jin-Hee Chang; Dae-Keun Park Kumoh,National University of Technology Solution blending was used to prepare nanocomposites of ethylene terephthalate/ethylene naphthalate copolymer and hexadecylamine treated organoclay. Blends were examined for tensile properties and thermal stability, and it was found that the addition of 4 percent clay gave the optimum improvement in both these properties. From scanning electron microscopy and transmission electron microscopy studies, agglomeration of clay particles was observed at 6 percent loadings of clay, but below 4 percent, high dispersion of particles was noted. Optical clarity of films cast from solution was also assessed and found to decrease slightly with increasing filler level. 20 refs. SOUTH KOREA

Accession no.839594 Item 200 Polymer Engineering and Science 41, No.12, Dec. 2001, p.2226-30 POLYIMIDE NANOCOMPOSITES: COMPARISON OF THEIR PROPERTIES WITH PRECURSOR POLYMER NANOCOMPOSITES Chang J-H; Park K M Kumoh,National University of Technology Poly(amic acid)/organoclay hybrids were produced by the solution intercalation method using dodecylamine

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montmorillonite, as filler, and polyimide hybrids obtained therefrom by heat treatment at various temperatures. The dispersibility of the organoclay in the polymer, heat stability, mechanical properties, morphology and gas permeability of the hybrids were examined and the properties of the precursor hybrids compared with those of hybrids produced from polyimide. 27 refs. KOREA

Accession no.839388 Item 201 Polymer Engineering and Science 41, No.10, Oct.2001, p.1794-802 EPOXY + MONTMORILLONITE NANOCOMPOSITE: EFFECT OF COMPOSITION ON REACTION KINETICS Butzloff P; D’Souza N A; Golden T D; Garrett D North Texas,University; Bell Helicopter Textron Inc. The effects of montmorillonite layered silicates on the curing kinetics of an epoxy resin were studied. DSC was used to probe the changes in reactivity due to the presence of montmorillonite and due to the diamine curing agent. The enthalpy of polymerisation was strongly affected at compositions greater than 5 wt % montmorillonite for epoxy/montmorillonite reactions. On introduction of the curing agent, epoxy resin/amine kinetics dominated that reaction for all compositions except for a montmorillonite concentration of 2.5 wt %. X-ray diffraction was used to examine whether the reacted system was exfoliated. The results showed a strong montmorillonite composition dependence on the exfoliated state. TEM of the cured epoxy resins confirmed a mixed intercalated and exfoliated dispersion at compositions having more than 2.5 wt % montmorillonite. 21 refs. USA

Accession no.836362 Item 202 Chemistry of Materials 13, No.10, Oct.2001, p.3796-809 SOLID-STATE NMR INVESTIGATION OF PARAMAGNETIC NYLON-6 CLAY NANOCOMPOSITES. II. MEASUREMENT OF CLAY DISPERSION, CRYSTAL STRATIFICATION, AND STABILITY OF ORGANIC MODIFIERS VanderHart D L; Asano A; Gilman J W US,National Inst.of Standards & Technology NMR measurements of nylon-6/clay nanocomposites having nominally 5 mass % clay were performed, with emphasis on measurements with application to processing. A relative assay was proposed for the quality of the clay dispersion for families of similarly formulated nanocomposites when paramagnetic montmorillonite clays were used. The spatial stratification of any components that could be spectrally identified was also

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References and Abstracts

USA

measurements, TGA and cone calorimetry. The onset temp. of the degradation was increased by about 50C and the peak heat release rate was reduced by 27 to 58%, depending on the amount of clay that was present. The mass loss rates were also significantly reduced in the presence of the clay. 15 refs.

Accession no.836333

USA

investigated. The chemical stability of the organic modifier (specifically dimethyl dehydrogenated-tallow ammonium ion) through the processing stage where polymer/clay melt-blending occurred was examined. 20 refs. (Pt.I, ibid, p.3781-95)

Item 203 Chemistry of Materials 13, No.10, Oct.2001, p.3781-95 SOLID-STATE NMR INVESTIGATION OF PARAMAGNETIC NYLON-6 CLAY NANOCOMPOSITES. I. CRYSTALLINITY, MORPHOLOGY, AND THE DIRECT INFLUENCE OF FE3+ ON NUCLEAR SPINS VanderHart D L; Asano A; Gilman J W US,National Inst.of Standards & Technology Several exfoliated nylon-6/clay nanocomposites were investigated and compared with pure nylon-6 using solidstate NMR, both proton and carbon-13. The composites nominally had 5 mass % clay and were generated both by blending and by in-situ polymerisation. The crystallinity and morphology of the nanocomposites were studied and the stability of the nylon-6 crystal forms that developed upon melt crystallisation was examined. The influence of the paramagnetic Fe3+, embedded within the clay layers, on nuclear spins that were confined in galleries where the maximum distance from a clay surface was only 0.4 nm. A proper understanding of the impact of Fe3+ on both the line width and the relaxation behaviour of the nearby nuclear spins provided the basis for understanding the perturbation on relaxation of the more distant spins in the nanocomposites. 47 refs. USA

Accession no.836332

Accession no.836331 Item 205 Chemistry of Materials 13, No.10, Oct.2001, p.3516-23 POLYPROPYLENE/MONTMORILLONITE NANOCOMPOSITES. REVIEW OF THE SYNTHETIC ROUTES AND MATERIALS PROPERTIES Manias E; Touny A; Wu L; Strawhecker K; Lu B; Chung T C Pennsylvania,State University The literature on the synthesis and properties of PP/ montmorillonite nanocomposites is reviewed. Nanocomposite formation is shown to be achieved in two ways, either by using functionalised PPs and common organo-montmorillonites or by using neat/unmodified PP and a semi-fluorinated organic modification for the silicates. All the hybrids can be formed by solventless melt-intercalation or extrusion and the resulting polymer/ inorganic structures are characterised by the coexistence of intercalated and exfoliated montmorillonite layers. Addition of a small amount, typically less than 6 wt %, of these nanoscale inorganic fillers is shown to promote concurrently several of the PP material properties, including improved tensile characteristics, higher heat deflection temp., retained optical clarity, high barrier properties, better scratch resistance and increased flame retardancy. 32 refs. USA

Item 204 Chemistry of Materials 13, No.10, Oct.2001, p.3774-80 FIRE PROPERTIES OF POLYSTYRENE-CLAY NANOCOMPOSITES Jin Zhu; Morgan A B; Lamelas F J; Wilkie C A Marquette,University; US,National Inst.of Standards & Technology PS-clay nanocomposites were prepared using a bulk polymerisation technique. Three onium salt were used to prepare the nanocomposites, two being functionalised ammonium salts and the third a phosphonium salt. Using TGA/FTIR, both ammonium and phosphonium treatments were shown to degrade by a Hofmann elimination mechanism at elevated temps. TGA/FTIR showed that the phosphonium treatment was the most thermally stable treatment when compared with the two ammonium salts. The nanocomposites were characterised by X-ray diffraction, TEM, strength and EB

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Accession no.836316 Item 206 Polymer Engineering and Science 41, No.9, Sept.2001, p.1514-20 PREPARATION AND CHARACTERIZATION OF POLYIMIDE NANOCOMPOSITES WITH DIFFERENT ORGANO-MONTMORILLONITES Jin-Hae Chang; Kwang Min Park; Donghwan Cho; Hee Sam Yang; Kyo Jin Ihn Kumoh,National University of Technology; Kumoh Plastic Co.Inc.; Kangwon,National University Polyamic acid nanocomposites were synthesised from a DMAc solution with two organophilic montmorillonites(organo-MMTs). They were then heated at various temps. under vacuum, yielding 15 to 20 micrometer thick films of polyimide/organo-MMT hybrid with different clay contents (1-8 wt %). Dodecylamine(C12-) and hexadecylamine(C16-) were

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used as aliphatic alkylamines in organo-MMT. The ultimate strength monotonically increased with increasing clay content in the polymer matrix. Maximum enhancement in the initial modulus was observed for the blends containing 2 wt % clay with two types of organoclays and values did not alter significantly with further increases in clay content. Additions of only 2 wt % C12and C16-MMT to the polyimide were shown to cause 94 to 95% reduction in oxygen gas permeability. This was caused by the barrier properties of the clay layers dispersed in the composite. In general, C16-MMT was more effective than C12-MMT in increasing both the tensile properties and the gas barrier in a polyimide matrix. Intercalations of the polymer chains in clay were examined by wide-angle X-ray diffraction, SEM and TEM. 20 refs. KOREA

Accession no.836151 Item 207 Polymer 42, No.25, 2001, p.10063-70 PREPARATION AND CRYSTALLIZATION BEHAVIOR OF SYNDIOTACTIC POLYSTYRENE-CLAY NANOCOMPOSITES Chen-Rui Tseng; Jeng-Yue Wu; Hsin-Yi Lee; FengChih Chang Taiwan,National Chiao-Tung University; Taiwan,National Chung-Hsing University; Taiwan,Synchrotron Radiation Research Centre Solution blending was used to prepare syndiotactic polystyrene (sPS) and clay nanocomposites with up to 10 percent clay addition in the presence of a cationic surfactant. The surfactant (cetyl pyridium chloride) was necessary to achieve miscibility between clay and polymer. Dispersion was assessed using X-ray diffraction and transmission electron microscopy. Some intercalation of the polystyrene into the clay layers was observed, and studies with differential scanning calorimetry and Fourier transform infrared spectroscopy showed that formation of the thermodynamically more stable beta form of crystal in the sPS was facilitated in the presence of the clay. 24 refs. TAIWAN

Accession no.835240 Item 208 Polymer 42, No.25, 2001, p.10013-9 PP/CLAY NANOCOMPOSITES PREPARED BY GRAFTING-MELT INTERCALATION XIaohui Liu; Quijiu Wu Lulea,University of Technology; Beijing,Institute of Chemistry A new type of organophilic clay with a larger interlayer spacing than normal alkyl aluminium modified clays, and

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incorporating an unsaturated co-intercalation monomer, epoxypropyl methacrylate, was melt mixed and grafted into a polypropylene matrix at different loading levels up to 7 percent using a twin screw compounding extruder at different temperatures. X-ray diffraction and transmission electron microscopy confirmed that the dispersion effect of the silicate layers was improved. Thermal characteristics were analysed using differential scanning calorimetry and mechanical analysis of the samples was carried out using dynamic mechanical analysis and tensile testing. Stiffness, tensile modulus and tensile strength of the material increased with loading of clay. The glass transition temperature was reduced with clay loadings of up to 3%, but increased at loadings above this point. Both notched impact strength and crystal structure were virtually unchanged with clay loading, but crystallisation rate increased due to nucleation by the silicate layers. 32 refs. CHINA; EUROPEAN UNION; SCANDINAVIA; SWEDEN; WESTERN EUROPE

Accession no.835234 Item 209 Polymer 42, No.25, 2001, p.10007-11 POLYMER-LAYERED SILICATE NANOCOMPOSITES. 1. A STUDY OF POLY(ETHYLENE OXIDE)/SODIUMMONTMORILLONITE NANOCOMPOSITES AS POLYELECTROLYTES AND POLYETHYLENEBLOCK-POLY(ETHYLENE GLYCOL) COPOLYMER/SODIUM-MONTMORILLONITE NANOCOMPOSITES AS FILLERS FOR REINFORCEMENT OF POLYETHYLENE Bing Liao; Mo Song; Haojun Liang; Yongxin Pang Loughborough,University Developments of new kinds of fillers for polymer reinforcement and polyelectrolytes has been examined by the preparation, by melt mixing, of nanocomposites of sodium montmorillonite with polyethylene oxide or polyethylene/polyethylene glycol block copolymers. The tensile strength of polyethylene could be improved by a significant amount when small amounts (up to 15 percent) of these materials were added. In the preparation of the nanocomposites, the intercalation of the polymer into the filler increases with the thermal mixing time. Characterisation of these materials utilised thermogravimetric analysis, differential scanning calorimetry and ionic conductivity. 19 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.835233 Item 210 Polymer 42, No.25, 2001, p.9975-85 TEMPERATURE DEPENDENCE OF POLYMER CRYSTALLINE MORPHOLOGY IN NYLON

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References and Abstracts

6(MONTMORILLONITE NANOCOMPOSITES) Lincoln D M; Vaia R A; Wang Z-G; Hsiao B S; Krishnamoorti R Wright-Patterson Air Force Base; New York,State University; Houston,University The effects of sample preparation, using melt mixed and in-situ polymerised samples of polyamide-6 unfilled and filled with a nanodispersion of montmorillonite, and prepared by extrusion and compression moulding, on the crystal structure of the polymer at temperatures up to melting temperature were examined using X-ray scattering and modulated differential scanning calorimetry. It was shown that the presence of the aluminosilicate layers of the clay altered the relationship between alpha and gamma phase behaviour of the material, with unfilled polyamide exhibiting alpha phase behaviour, and gamma phase behaviour being stabilised with filler addition. Relative fractions of alpha and gamma phase, and the temperature dependence of total crystallinity, is very dependent on filler content with the gamma phase being preferentially in the region of the silicate plates and alpha phase being present away from the polymer-silicate interphase region. Crystal structure and stability was shown to be very dependent on both temperature and sample preparation methods. 33 refs. USA

Accession no.835230 Item 211 Polymer 42, No.25, 2001, p.9929-40 NYLON 6 NANOCOMPOSITES: THE EFFECT OF MATRIX MOLECULAR WEIGHT Fornes T D; Yoon P J; Keskkula H; Paul D R Texas,University at Austin Preparation, using twin screw extruder compounding, and characterisation of montmorillonite filled polyamide-6 nanocomposites with different filling levels and using polymers of low, medium and high molecular weight is reported. Characterisation of the blends using X-ray diffraction, transmission electron microscopy, mechanical properties and melt rheology indicated that increases in viscosity, particle density, modulus, yield strength and elongation at break occur with increasing molecular weight of the polymer. Differences of behaviour of the three different molecular weight composites were explained by the differences noted in the shear stress of the materials when capillary and parallel plate methods were used. Proposals are given for the mechanisms of exfoliation of the clay during melt mixing. 51 refs. USA

Accession no.835226 Item 212 Polymer 43, No.1, 2002, p.45-53

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POLYBENZOXAZINE/CLAY HYBRID NANOCOMPOSITES: INFLUENCE OF PREPARATION METHOD ON THE CURING BEHAVIOUR AND PROPERTIES OF POLYBENZOXAZINES Tsutomu Takeichi; Rachib Zeidam; Tarek Agag Toyohashi,University of Technology Different types of polybenzoxazine/clay nanocomposites were prepared from organically modified montmorillonite (OMMT) and mono- or bifunctional benzoxazine, 3phenyl-3,4-dihydro-2H-1,3-benzoxazine (Pa) or bis(3phenyl-3,4-dihydro-2H-1,3-benzoxazinyl) isopropane (Ba) respectively. The OMMT was obtained by cation exchange of montmorillonite (OMMT) with ammonium salts of amines, e.g. tyramine, phenylethylamine, aminolauric acid, and dodecyl amine. The polybenzoxazine/clay nanocomposites were obtained by two different methods, i.e. a melt and a solvent method. In the solvent method, OMMT was dispersed in an organic solvent and blended with benzoxazine. X-ray diffraction measurements of the nanocomposites indicated that the method of blending and the type of solvent played a crucial part in dispersion of the OMMT in the polybenzoxazine matrix. Differential scanning calorimetry indicated that inclusion of OMMT of any kind resulted in significant lowering of the benzoxazine curing exotherm. The nanocomposite showed higher glass transition temperatures than the pure resins. Dynamic and isothermal thermogravimetric analysis indicated that inclusion of clay improved the thermal stability of the composites. 27 refs. JAPAN

Accession no.835150 Item 213 Composite Interfaces 8, No.5, 2001, p.345-53 PRESSURE-VOLUME-TEMPERATURE RELATIONS OF A POLY-E-CAPROLACTAM AND ITS NANOCOMPOSITE Simha R; Utracki L A; Garcia-Rejon A Case Western Reserve University; Canada,National Research Council The equation of state of a poly-e-caprolactam melt, PA6, of-molar mass Mn = 22 kg/mol, is investigated in a Gnomix apparatus between 300 and 560 K, and pressures up to 150 MPa. Corresponding measurements are performed with addition of 1.6 wt.% of montmorillonite exfoliated particles. Reductions in specific volume of about 1 and 1.4% respectively, at 10 and 150 MPa, are observed. For the melt, excellent agreement between experiment and the results from lattice-hole theory is found for both systems. Addition of the nanoparticles reduces the hole (free volume) fraction by 14%. Evidently, the hole fraction is a sensitive indicator of structural changes. It is noteworthy that such a small quantity of added nanoparticles increases the tensile strength by about

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14% and modulus by 26%, at a cost of reduction in the elongation at break by about 25%. For a treatment of the PNC, and as an approximation, an earlier model of a particulate composite is adopted. To calculate the binary interaction parameters it is assumed that: the clay particles are in the form of flat discs, 100 nm diameter and 1 nm thick; the hard core segments of polymer interactions and of solid occupy the same lattice volume; and the energetic interactions of polymer with solid are given by the geometric average between the two self-interactions. 9 refs. CANADA; USA

Accession no.835050 Item 214 Polymer Degradation and Stability 74, No.1 2001, p.33-7 PHOTO-OXIDATION OF POLYMERICINORGANIC NANOCOMPOSITES: CHEMICAL, THERMAL STABILITY AND FIRED RETARDANCY INVESTIGATIONS Tidjani A; Wilkie C A Marquette,University Nanocomposites of polypropylene-graft-poly(maleic anhydride) (PP-g-MA)/clay and polypropylene (PP)/clay, with intercalated structures, were prepared by melt blending, and exposed to UV irradiation. The photooxidative stability was evaluated using Fourier transform infrared and UV spectroscopy. The influence of photooxidation on the thermal stability and fire resistance of the nanocomposites was evaluated by thermogravimetric analysis and cone calorimetry. The intercalated PP nanocomposites exhibited enhanced thermal stability compared with pure PP and PP-g-MA. The presence of the clay adversely affected the photooxidation resistance of the polymers. 11 refs. USA

Accession no.832484 Item 215 Journal of Applied Polymer Science 82, No.6, 7th Nov.2001, p.1444-8 SYNTHESIS AND CHARACTERISATION OF ELASTOMERIC POLYURETHANE/CLAY NANOCOMPOSITES Jisheng Ma; Shufan Zhang; Zongneng Qi Beijing,Institute of Chemistry Intercalative polymerisation technology was applied to the synthesis of an elastomeric polyurethane/clay (PU/ clay) nanocomposite. The results of wide-angle X-ray diffraction (WAXD) indicated that the clay gallery distance in the hybrid was increased from 1.9 to at least 4.4 nm. Introduction of clay into the PU matrix increased the tensile strength and elongation at break, and at a clay content of about 8% increased them by factors of 2 and 5 respectively compared with pure PU. The clay

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intercalative route to the nanocomposite synthesis affected the thermal properties of the nanocomposite. The clay used was sodium montmorillonite clay. 5 refs. CHINA

Accession no.832046 Item 216 Journal of Applied Polymer Science 82, No.6, 7th Nov.2001, p.1391-403 CLAY NANOLAYER REINFORCEMENT OF CIS1,4-POLYISOPRENE AND EPOXIDISED NATURAL RUBBER Yen T Vu; Mark J E; Pham Ly H; Engelhardt M Cincinnati,University; Hanoi,Institute of Chemistry; Yokohama Tire Corp. The conditions required for dispersing sodium montmorillonite clay nanolayers into cis-1,4-polyisoprene (synthetic) natural rubber (NR) and epoxidised natural rubbers (ENR) containing 25 and 50 mole% epoxide were established. The clay was used as a pristine layered silicate or as organically modified silicate layers, to make the galleries more hydrophobic and thus more compatible with the elastomers. Ion exchange with alkyl ammonium cations was used for chemical modification. The clays were incorporated into the elastomers by mixing the components in a standard internal blender or by mixing their dispersions in toluene or methyl ethyl ketone. The X-ray diffraction patterns indicated intercalation of the NR and ENR into the silicate interlayers, with subsequent exfoliation of the silicate layers into the elastomer matrices. The observed mechanical reinforcement of the elastomers by the intercalated and exfoliated clays was strongly dependent on the extent of dispersion of the silicate layers into the rubber matrices, and was of primary interest. 61 refs. USA; VIETNAM

Accession no.832041 Item 217 Polymer 42, No.21, 2001, p.9015-23 TIME-RESOLVED SHEAR BEHAVIOR OF ENDTETHERED NYLON 6-CLAY NANOCOMPOSITES FOLLOWED BY NONISOTHERMAL CRYSTALLIZATION Medellin-Rodriguez F J; Burger C; Hsaio B S; Chu B; Vaia R; Phillips S New York,State University; Wright-Patterson Air Force Base; US,Air Force Research Laboratory The orientation behaviour of nylon-6-montmorillonite nanocomposites was studied by in-situ synchrotron Xray techniques. The system could be oriented under relatively low shear fields and temperatures immediately above the experimental melting temperature. Gradual alignment of the through-view small angle X-ray scattering patterns indicated the rotation of the end-

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References and Abstracts

tethered clay along the shear direction. High temperature relaxation of the clay after shear was substantially longer than the polymer. Thus, non-isothermal crystallisation could be used to preserve the orientation of the clay induced by shear. Most of the clay planar alignment in the composites showed the gamma crystal form which is associated with extended chain crystallisation. Nylon 6, however, crystallised into the alpha form which is associated with quiescent crystals involving folded chains. The shear result were compared with quiescent crystallisation where the nanocomposites showed the gamma habit and the nylon-6 homopolymer showed mixed alpha/gamma habits. 23 refs. USA

Accession no.831912

compounding is described. Characterisation was carried out using elemental analysis, gel permeation chromatography, Fourier transform infrared spectroscopy, thermogravimetric analysis, transmission electron microscopy and X-ray diffraction. The hydrophilicity of the maleic anhydride grafted polymer and chain length of the organic modifier in the clay were found to control the intercalation and exfoliation behaviour of the blend, with more than 16 methylene groups in the alkylamine clay modifier required to give exfoliated nanocomposites. With a different clay modifier exfoliated nanocomposites were achieved with maleic anhydride grafting levels of more than 0.1 percent. When pure polyethylene was used, the thermodynamic equilibrium state of the clay surface controlled the intercalation capability of the blend. 41 refs. SOUTH KOREA

Item 218 Polymer 42, No.24, 2001, p.9837-42 PREPARATION OF CLAY-DISPERSED POLY(STYRENE-CO-ACRYLONITRILE) NANOCOMPOSITES USING POLY(ECAPROLACTONE) AS A COMPATIBILIZER Seong Woo Kim; Won Ho Jo; Moo Sung Lee; Moon Bae Ko; Jae Young Jho Seoul,National University; Chonnam,National University

Accession no.831807

A two-stage melt mixing process was used to prepare a nanocomposite of clay in a copolymer of styrene and acrylonitrile (SAN) with polycaprolactone (PCL) as compatibiliser. The first stage involved melt mixing of the clay with the compatibiliser, followed by melt mixing this into the SAN. The effect of mixing conditions was evaluated by examination of nanocomposites prepared under different shear rates by X-ray diffraction, scanning electron microscopy and dynamic mechanical thermal analysis for both the PCL mix and the finished SAN material. Lower temperatures and extended mixing times were shown to give the best intercalation and exfoliation of the clay. Some phase separation was observed between the SAN and PCL by a return of peaks associated with the intercalated structure of the organosilicate in the final product. 12 refs.

A solution-dispersion method was used to prepare polysulphone/organoclay nanocomposites which were then characterised using X-ray diffraction, transmission electron microscopy, thermogravimetric analysis and tensile measurements. Three levels of clay addition were used, 1,3 and 5 weight percent, and compared to the pure polymer, improvements in tensile and thermal properties were reported. 206 refs

KOREA

Accession no.831809 Item 219 Polymer 42, No.24, 2001, p.9819-26 SYNTHESIS AND CHARACTERIZATION OF MALEATED POLYETHYLENE/CLAY NANOCOMPOSITE Ki Hyun Wang; Min Ho Choi; Chong Min Koo; Keong Suk Choi; In Jae Chung Korea,Advanced Institute of Science and Technology Preparation and characterisation of maleic anhydride grafted polyethylene and clay nanocomposites by melt

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Item 220 Polymer 42, No.24, 2001, p.9783-9 SYNTHESIS, STRUCTURE, MECHANICAL PROPERTIES, AND THERMAL STABILITY OF SOME POLYSULFONE/ORGANOCLAY COMPOSITES Sur G S; Sun H L; Lyu S G; Mark J E Yeungnam,University; Cincinnati,University

KOREA; USA

Accession no.831803 Item 221 Polymer 42, No.24, 2001, p.9763-9 THE NOVEL POLYMER ELECTROLYTE NANOCOMPOSITE COMPOSED OF POLY(ETHYLENE OXIDE), LITHIUM TRIFLATE AND MINERAL CLAY National Chiao Tung University Edited by: Hsien-Wei Chen; Feng-Chitz Chang The ionic conductivity of a polyethylene oxide (PEO) lithium triflate based electrolyte is increased by a factor of up to sixteen by addition of an optimum quantity of montmorillonite clay. Investigation of the causes of this, using X-ray diffraction, differential scanning calorimetry, Fourier transform infrared analysis and alternating current impedance, indicate that addition of the clay increases the crystallinity of the PEO due to electrical interactions between the clay and the lithium cation. Three types of

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References and Abstracts

complexes have been identified, on each in the clay and PEO and one at the interphase between the two. The fraction of free ions is also increased in this system by improvement to the solubility of the lithium salts caused by the action of the clay. 32 refs. TAIWAN

Accession no.831801 Item 222 Journal of Polymer Science: Polymer Physics Edition 39, No.17, 1st Sept.2001, p.2097-107 CRYSTALLIZATION KINETICS AND CRYSTALLIZATION BEHAVIOR OF SYNDIOTACTIC POLYSTYRENE/CLAY NANOCOMPOSITES Chen-Riu Tseng; Hsin-Yi Lee; Feng-Chih Chang Taiwan,National Chiao-Tung University; Taiwan,Synchrotron Radiation Research Centre Syndiotactic polystyrene (sPS) was mixed with clay or clay treated with cetyl pyridinium chloride in a corotating twin screw compounding extruder. The resulting compounds were characterised using infrared spectroscopy, differential scanning calorimetry, X-ray diffraction and transmission electron microscopy. Dispersion of the treated clay was found to be better than the untreated clay. Crystallisation kinetics of the blends were examined and it was found that the crystallisation rate constant increased with increasing clay content. It was also determined that the clay had the effect of reducing the size and increasing the number of the beta-crystal lamellae in the sPS compared to the pure polymer. 28 refs. TAIWAN

Accession no.830205 Item 223 Journal of Polymer Science: Polymer Physics Edition 39, No.17, 1st Sept.2001, p.1968-75 DYNAMIC MECHANICAL AND DIELECTRICAL PROPERTIES OF POLY(VINYL ALCOHOL) AND POLY(VINYL ALCOHOL)-BASED NANOCOMPOSITES Gendoya I; Lopez D; Alegria A; Mijangos C CSIC; Pais Vasco,Universidad Dielectric spectroscopy and dynamic mechanical analysis were used to study the effect on the relaxations of polyvinyl alcohol (PVAlc) films which have up to 28.7 percent of nanosized magnetic filler treated with sulphonated polystyrene added to them. Addition of the filler at levels up to 10 percent increased the glass transition temperature (Tg), but at levels higher than 10 percent filler the Tg dropped due to plasticisation effects of water retained in the filler. Beta and gamma relaxation processes of PVAlc were unaffected by addition of fillers. 36 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; SPAIN; WESTERN EUROPE

Accession no.830193

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Item 224 Journal of Applied Polymer Science 82, No.3, 17th Oct.2001, p.555-61 INTERCALATIVE REDOX POLYMERIZATION AND CHARACTERIZATION OF POLY(4VINYLPYRIDINE)-VERMICULITE NANOCOMPOSITE Dhamodharan R; Samuel J D J S; Rajeswari M K Indian Institute of Technology Vinyl pyridine was polymerised in the gallery spacing of vermiculite to form an intercalate polymer in the nanocomposite. The nanocomposite was suitable for use in waste removal and recovery and its efficacy was shown by the removal of colour from dye wastewater. Polymerisation was achieved using redox polymerisation in the presence of copper ions that had been ion exchanged with the original magnesium ions in the vermiculite. Characterisation of the nanocomposite using infrared, ultraviolet and electron spin resonance spectroscopy, thermogravimetric analysis, X-ray diffraction and differential scanning calorimetry indicated that the polymer was confined in the gallery of the vermiculite and was between 18 and 19 percent of the total mass of the composite. Thermal stability of polymer was improved and both a lack of glass transition and an increase in gallery spacing observed with X-ray diffraction proved the virtually total intercalative nature of the nanocomposite. 9 refs. INDIA

Accession no.830171 Item 225 Colloid & Polymer Science 279, No.8, Aug.2001, p.819-22 SYNTHESIS OF POLYURETHANE/CLAY INTERCALATED NANOCOMPOSITES Hu Y; Song L; Xu J; Yang L; Chen Z; Fan W China,University of Science & Technology A PU/organophilic layered montmorillonite (OMT) nanocomposite was synthesised via a two-stage process. Firstly, a polyether (poly(propylene oxide))/OMT hybrid was prepared. the polyether was dispersed and intercalated into the gallery of the layered silicate. Then the polyether/ OMT reacted with TDI and diglycol to obtain PU/OMT intercalated nanocomposites as confirmed by X-ray diffraction and high-resolution electron microscopy. The content of the hard segment of PU and OMT affected the basal spacing of the nanocomposite. 14 refs. CHINA

Accession no.830166 Item 226 Polymer Bulletin 46, No.6, July 2001, p.499-505 EFFECT OF ASPECT RATIO OF CLAY ON MELT EXTENSIONAL PROCESS OF

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References and Abstracts

MALEATED POLYETHYLENE/CLAY NANOCOMPOSITES Ki Hyun Wang; Mingzhe Xu; Yeong Suk Choi; In Jae Chung Korea,Advanced Institute of Science & Technology A maleated PE (PEMA) nanocomposite with a high aspect ratio clay (PEMA/montmorillonite), one with a low aspect ratio clay (PEMA/laponite) and a macrocomposite with silica (PEMA/silica) were prepared by melt compounding. The PEMA/montmorillonite nanocomposite showed higher storage moduli, complex viscosity and melt tension than the other two composites studied. It also showed longer drawability and lower neck-in during melt processing, and showed an easy orientation in the polymer in the melt drawing direction. 33 refs. SOUTH KOREA

Accession no.830154 Item 227 Polymer 42, No.23, 2001, p.9633-40 HIERARCHICAL STRUCTURE AND PROPERTIES OF INTERCALATED POLYPROPYLENE/CLAY NANOCOMPOSITES Nam P H; Maiti P; Okamoto M; Kotaka T; Hasegawa N; Usuki A Toyota Technological Institute; Toyota Central R & D Laboratories Inc. Using maleic anhydride modified polypropylene (PPMA) and organophilic clay the intercalated nanocomposites of polypropylene/clay (PPCNs) were prepared via melt extrusion. Wide-angle X-ray diffraction, small-angle X-ray scattering, transmission electron microscopy, polarising optical microscopy and light scattering were used to study the hierarchical structure of the PPCNs from the structure of confined PP-MA chains, in the space of a few nanometer width between silicate galleries to crystalline lamellae of 7-15 nm thick and spherulitic texture of 10 micrometers. The PPCNs formed rod-like crystalline texture in the 10 micrometer length scale, after crystallisation had taken place at 80 degrees C. This crystalline texture consisted of the inter-fibrillar structure including gamma-phase crystallite caused by the reduction of the PP-MA chains mobility due to the intercalation of the polypropylene chains in the space between silicate galleries and the narrow space surrounded by the dispersed clay particles. Compared with polypropylene matrix without clay the intercalated PPCNs showed and enhanced moduli. 27 refs.

ON THE EXTENT OF EXFOLIATION IN ORGANOCLAY-BASED NANOCOMPOSITES Dennis H R; Hunter D L; Chang D; Kim S; White J L; Cho J W; Paul D R Southern Clay Products Inc.; Akron,University; Texas,University A study was carried out on the effects of the chemistry of the clay surface and of the mixing method on the properties of clay/polyamide-6 nanocomposites. Using 4 different types of extruders with multiple screw designs, montmorillonite treated with two different tallow ammonium modifiers were melt blended with polyamide6. X-ray diffraction, transmission electron microscopy and mechanical property tests were used to characterise the mixtures of organoclay and polyamide-6. The degree of dispersion is interpreted in terms of the residence time distribution in the extruder and the intensity of shear. A model for organoclay delamination in a polymer melt is proposed that incorporates the role of both shear and time. 31 refs. USA

Accession no.830130 Item 229 Antec 2001.Conference proceedings. Dallas, Texas, 6th-10th May, 2001, paper 650 CRYSTALLIZATION KINETICS OF POLY(ETHYLENE TEREPHTHALATE) BASED IONOMER NANOCOMPOSITE MATERIALS Carter C M Southern Mississippi,University (SPE) Suspensions of organically-modified and sodium montmorillonites in hexafluoropropanol were added to hexafluoropropanol solutions of poly(ethylene terephthalate) (PETP) and of sulphonated PETP (2-10 mol% sulphoisophthalic acid), and nanocomposite films prepared by casting. Crystallisation temperatures and rates were determined by differential scanning calorimetry. The introduction of the clays into PETP and into sulphonated PETP containing 2 and 6 mol% sulphoisophthalic acid resulted in an increase in the crystallisation temperature and a decrease in the crystallisation half-times. The organically modified clay was the most effective nucleating agent, the Na-montmorillonite giving the highest crystallisation temperatures and the slower crystallisation half-times. 6 refs. USA

Accession no.830082

JAPAN

Accession no.830142 Item 228 Polymer 42, No.23, 2001, p.9513-22 EFFECT OF MELT PROCESSING CONDITIONS

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Item 230 Rubber and Plastics News 31, No.3, 3rd Sept.2001, p.22 GM TO USE TPO NANOCOMPOSITE AUTO PARTS Begin S

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References and Abstracts

General Motors will commercialise the first thermoplastic olefin-based nanocomposite part on its upcoming minivans. Optional step assists on the 2002 GMC Safari and Chevrolet Astro vans will be moulded from the new material. Filled with tiny flakes of the clay mineral smectite, the nanocomposite weighs up to 20% less than traditional talc-filled TPOs, is more ductile at lowtemperature impacts, more recyclable, can be moulded on existing tooling and eventually could include UV stable colour pigments, yielding a Class A surface while eliminating the paint process. GM is developing other new applications for the trade secret material including exterior body panels, cladding, tool boxes and interior components. GENERAL MOTORS CORP.

(SPE) Polyamides based on polyamide-6 (PA-6) and blends of PA-6 with amorphous polyamides for high oxygen barrier food packaging applications are described. The oxygen barrier properties are also enhanced by the addition of a proprietary oxygen scavenging moiety and/or nanoclays. The nanoclay is introduced during polymerisation rather than melt compounding, so giving better barrier properties and lower haze levels. The polyamides are suitable for cast and blown film, and as barrier layers in coextrusion blow moulded bottles and co-injection stretch blow moulded poly(ethylene terephthalate) bottles. USA

Accession no.827185

USA

Accession no.829829 Item 231 Rubber Chemistry and Technology 74, No.2, May/June 2001, p.221-35 RUBBER NANOCOMPOSITES: MORPHOLOGY AND MECHANICAL PROPERTIES OF BR AND SBR VULCANIZATES REINFORCED BY ORGANOPHILIC LAYERED SILICATES Ganter M; Gronski W; Reichert P; Muelhaupt R Freiburg Materialsforschungszentrum Rubber compounds based on polybutadiene or SBR containing organophilic layered silicates were prepared. Organophilic silicates were swollen in a rubber/toluene solution. Matrix-filler reactive bonding was performed by adding bis(triethoxysilylpropyl)tetrasulphane(TESPT) during swelling. Good dispersion of organoclay nanofillers in rubber matrices was demonstrated by TEM and atomic force microscopy exhibiting intercalated and partially exfoliated silicate layers. Matrix-filler interfacial coupling by TESPT led to reduced strain at break and reduced hysteresis for both organoclay and silica-based vulcanisates as expected for successful matrix/filler coupling. Organoclay vulcanisates exhibited enhanced hysteresis when compared with silica compounds. This was related to orientation and sliding of anisotropic silicate layers, as determined by on-line wide-angle Xray scattering measurements during cyclic tensile testing. 16 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.827613 Item 232 Antec 2001.Conference proceedings. Dallas, Texas, 6th-10th May, 2001, paper 455 NEW HIGH BARRIER, OXYGEN SCAVENGING POLYAMIDES FOR PACKAGING APPLICATIONS Socci E P; Akkapeddi M K; Worley D C Honeywell International Inc.

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Item 233 Antec 2001.Conference proceedings. Dallas, Texas, 6th-10th May, 2001, paper 432 EFFECT OF NANOPARTICLES AND PROCESSING CONDITIONS ON THE DEVELOPMENT OF STRUCTURAL HIERARCHY IN INJECTION MOLDED NYLON COMPOSITES Yalcin B; Cakmak M Akron,University (SPE) Polyamide-6 (PA-6), PA-6 melt compounded nanocomposite, and PA-6 polymerised nanocomposite were injection moulded using two injection speeds and two mould temperatures. Orientation was studied using polarised optical microscopy. Melting and crystallisation of compression moulded samples were studied using differential scanning calorimetry and wide angle X-ray diffraction. The presence of the nanofiller enhanced preferential orientation through the thickness of the moulded parts, even at mould temperatures close to the polymer melting temperature. 11 refs. USA

Accession no.827059 Item 234 Antec 2001.Conference proceedings. Dallas, Texas, 6th-10th May, 2001, paper 430 NEW MODEL FOR INTERPRETING NANOCOMPOSITE BEHAVIOR Beall G W St.Louis,Missouri Baptist College (SPE) A model for the prediction of nanocomposite properties was developed from the tortuous path model. It considers four distinct phases: clay; a surface modified phase; a constrained polymer phase, the size and stability of which is dependent upon intermolecular bonding energies; and a polymer phase similar to the pure polymer. The model predicts that: permeabilities may be higher or lower than those from the simple tortuous path model, depending

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References and Abstracts

upon the relative diffusion coefficients of the phases; permeability may be different for different permeants; for most polymers, nematic phases predominate above approximately 5 wt% clay; and the filler aspect ratio is not the only factor determining permeability. 18 refs. USA

Accession no.827057 Item 235 Macromolecules 34, No.16, 31st July 2001, p.5727-9 DRIVEN DIFFUSION OF CONFINED POLYMERS Lee J Y; Loring R F Cornell University Molecular dynamics simulations of the flow of polymers from a bulk melt into a slit were performed to model the formation kinetics of polymer-layered silicate nanocomposites. Calculations were compared with experimental observations for PS. 17 refs. USA

Accession no.826994 Item 236 Macromolecules 34, No.16, 31st July 2001, p.5398-407 ORGANIC/INORGANIC NANOCOMPOSITE STAR POLYMERS VIA ATOM TRANSFER RADICAL POLYMERIZATION OF METHYL METHACRYLATE USING OCTAFUNCTIONAL SILSESQUIOXANE CORES Costa R O R; Vasconcelos W L; Tamaki R; Laine R M Minas Gerais,Universidade Federal; Michigan,University Details are given of the atom transfer radical polymerisation of a nanocomposite consisting of dispersed nanosized silsesquioxane in PMMA. The effect of variations in initiator and catalyst concentrations and type of initiator on MWD of the polymers were investigated. 52 refs. BRAZIL; USA

Accession no.826957 Item 237 Polymer 42, No.19, 2001, p.8235-9 POLYAMIDE 6-CLAY NANOCOMPOSITES/ POLYPROPYLENE-GRAFTED-MALEIC ANHYDRIDE ALLOYS Xiaohui Liu; Quiju Wu; Bergland L A; Jiaqi Fan; Zongnang Qi Lulea,University of Technology; Chinese Academy of Sciences Polyamide 6-clay nanocomposites (PA6CN) based on montmorillonite show increasing brittleness with clay

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addition. PA6CN/PP-g-MAH alloys were prepared through blending PA6CN with propylene-grafted-maleic anhydride (PP-g-MAH). The dynamic mechanical temperature spectra, morphology, mechanical properties and water absorption of the alloys were studied. The notched impact strength of the alloys increased greatly compared with PA6CN and the alloys maintained their higher stiffness and strength than that of PA 6. Scanning electron microscopy was used to study the morphological properties and it showed a PP-g-MAH toughening phase dispersed in PA6CN matrix. As the PP-g-MAH content was increased, reduced water absorption was observed. 36 refs. CHINA; EUROPEAN UNION; SCANDINAVIA; SWEDEN; WESTERN EUROPE

Accession no.826668 Item 238 Journal of Polymer Science: Polymer Physics Edition 39, No.12, 15th June 2001, p.1360-70 CLAY-REINFORCED POLYAMIDE: PREFERENTIAL ORIENTATION OF THE MONTMORILLONITE SHEETS AND THE POLYAMIDE CRYSTALLINE LAMELLAE Varlot K; Reynaud E; Kloppfer M H; Vigier G; Varlet J Nancy,Universite Henri Poincare; Institut National des Sciences Appliquees; Rhodia Recherches The microstructure of polyamide-6/montmorillonite nanocomposites was characterised. Intercalated and exfoliated nanocomposites were prepared by the extrusion and injection of polyamide-6 and swollen montmorillonite respectively. The basal spacing was more homogeneous in swollen montmorillonite than in non-treated montmorillonite attributed to the presence of surfactant. Surfactant crystallites were observed in swollen montmorillonite and in the nanocomposites. The nanocomposites exhibited highly anisotropic properties attributed to the orientation of the montmorillonite sheets. Detailed investigation of the montmorillonite sheets preferential orientation by small-angle X-ray scattering (SAXS) found it was related to the injection direction. Also the average distance between two sheets was measured from the SAXS spectra and found that the sheets were parallel to each other and uniformly distributed in the sample. The crystallographic state of the polyamide6 matrix was analysed by wide-angle X-ray diffraction (WAXD) and differential scanning calorimetry (DSC), which showed it was mainly in the gamma form. This differed from the pure form of polyamide-6 where both alpha and gamma forms coexist. The montmorillonite therefore played a major role in the crystallisation of the polyamide-6 matrix. Consequently, the gamma form of polyamide-6 lamellae is expected to be the preferred orientation that will grow on the montmorillonite sheets. It is considered that the orientation of the montmorillonite sheets and the polyamide-6 lamella will play a major role in the mechanical properties of nanocomposites. 11 refs.

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EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; WESTERN EUROPE

Accession no.825483 Item 239 Chemistry of Materials 13, No.6, June 2001, p.2179-85 PREPARATION OF ORGANIC-INORGANIC NANOCOMPOSITES WITH A LAYERED TITANATE Sukpirom N; Lerner M M Oregon,State University A report is presented on the application of colloidal suspensions of exfoliated titania sheets, obtained in tetrabutylammonium hydroxide solutions, as precursors for the formation of lamellar titania nanocomposites with PEO and polyvinyl pyrrolidone and on the structural and compositional characterisation of these materials by Xray diffraction, TGA, DSC, FTIR and elemental analyses. Structural characterisation indicated that the PEO nanocomposites have polymer bilayers within titanate galleries. FTIR and thermal analyses indicated a reduced tetrabutylammonium cation content and water content relative to the intercalation compounds formed without polymer. 56 refs. USA

Accession no.825074 Item 240 Macromolecules 34, No.12, 5th June 2001, p.4098-103 POLY(METHYL METHACRYLATE) AND POLYSTYRENE/CLAY NANOCOMPOSITES PREPARED BY IN-SITU POLYMERIZATION Chanchun Zeng; Lee L J Ohio,State University PMMA/clay nanocomposites and PS/clay nanocomposites were synthesised by in-situ bulk polymerisation. The polarity and hydrophilicity of the initiators and monomers greatly affected the dispersion of the clay, because of the interactions of the monomers and initiators with the clay surface. Exfoliated PMMA and PS/clay nanocomposites with a clay concentration of 5 wt% were synthesised using a surfactant with a polymerisable group to modify the clay surface. The presence of clay substantially improved the dimensional stability of the polymer matrix in an exfoliated nanocomposite with uniform mesoscale (long range distribution) clay dispersion. 51 refs. USA

Accession no.824134 Item 241 Polymer 42, No.15, 2001, p.6545-6556 REINFORCEMENT OF

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POLY(DIMETHYLSILOXANE) NETWORKS BY MICA FLAKES Osman M A; Atallah A; Muller M; Suter U W ETH Zurich Spherical and plate-like particles are used to reinforce a poly(dimethylsiloxane) (PDMS) network. Laser diffraction, gas adsorption, cation exchange and scanning electron microscopy were used to examine the shape, size distribution, aspect ratio and surface area of the particles. The mechanical properties were measured of networks prepared with different crosslinker concentration in order to ascertain the optimal ratio of crosslinker to PDMS. Homogeneous distribution of the filler in the polymer matrix as well as complete dispersion of the particles are prerequisites for studying the influence of other parameters on the mechanical properties of composites. The elastic modulus of the PDMS dramatically increased by the addition of mica. The modulus rose with increasing diameter and aspect ratio as well as with the volume fraction of the particles. The plate-like particles enhanced the ultimate strength of the composite better than spheres. The strength enhancement was less dramatic and dependence on particle size was reversed compared to that of the modulus. The ultimate elongation of the mica composites was comparable to that of glass spheres. The polymer chains did not intercalate the aluminosilicate layers of mica, as expected. 32 refs. SWITZERLAND; WESTERN EUROPE

Accession no.823577 Item 242 Composites Science & Technology 61, No.9, 2001, p.1253-64 PREPARATION, STRUCTURE, PROPERTIES AND THERMAL BEHAVIOUR OF RIGID-ROD POLYIMIDE/MONTMORILLONITE NANOCOMPOSITES Magaraphan R; Lilayuthalert W; Sirivat A; Schwank J W Chulalongkorn,University; Michigan,University The above composites were produced from a solution of polyamic acid and dodecyl-montmorillonite (DMONT) using, as solvent, N-methyl-2-pyrrolidone and their thermal properties investigated by DMA. Cured films of the polyimide/DMONT hybrids were characterised by wide-angle X-ray diffraction, TEM, TGA and FTIR spectrocopy. The effects of DMONT content on the mechanical properties, water absorption, dielectric strength and onset of decomposition temperature were examined as well as the influence of DMONT content and polyimide flexibility on thermal expansion coefficient and of DMONT content and matrix flexibility on heat stability at high temperatures. The influence of high temperature thermal cycling on thermal properties was also examined. THAILAND; USA

Accession no.822962

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References and Abstracts

Item 243 Synthetic Metals 121, Nos.1-3, 15th March 2001, p.1325-6 SYNTHESIS AND ELECTRORHEOLOGY OF EMULSION INTERCALATED PANI-CLAY NANOCOMPOSITE Choi H J; Kim J W; Joo J; Kim B H Inha,University; Korea,University The electrorheological (ER) characteristics of three different polyaniline (PANI)/Na+-montmorillonite (MMT) nanocomposite systems obtained by an emulsion intercalation process were studied, and the nanocomposite particles were dispersed in silicone oil. Insertion of the PANI into the clay layer was studied by X-ray diffraction, which confirmed that the conductive PANI polymer was aligned with the clay layers. Dodecylbenzene sulphonate, used as both emulsifier and dopant, played an important part in the PANI-clay composites, and had an effect on the conductivity of the nanoparticles and their ER properties. ER fluids comprising PANI-clay composite showed typical ER behaviour and increased static yield stress under an applied electric field. 3 refs. KOREA

Accession no.821862 Item 244 Macromolecular Rapid Communications 22, No.8, 15th June 2001, p.616-9 NEW APPROACH TO ENHANCE THE YIELD STRESS OF ELECTRO-RHEOLOGICAL FLUIDS BY POLYANILINE-COATED LAYERED SILICATE NANOCOMPOSITES Park J H; Lim Y K; Park O O Korea,Advanced Institute of Science & Technology Details are given of the synthesis of polyaniline/ organoclay nanocomposite particles and electrorheological fluids by dispersing the particles in silicone oil. The effects of delaminated clay on the electrorheological yield stress were investigated and compared with other electro-rheological fluid systems. 15 refs. KOREA

Accession no.820204

the object of obtaining light-emitting devices (LED) based on environmentally stable polymer/layered silicate nanocomposite. The MEN-PPV/organo-clay ratio was 5/ 1 to 1/1 (w/w). The LED of the 1/1 blend gave the maximum quantum efficiency, 0.38% photons/electrons, which was increased 100-fold compared with the pure MEN-PPV layer device. The two-dimensional lamellartype nanocomposite device obtained had an electronic structure similar to that of known quantum well devices. 10 refs. KOREA

Accession no.819848 Item 246 Macromolecules 34, No.10, 8th May 2001, p.3255-60 SYNTHESIS AND CHARACTERIZATION OF PMMA NANOCOMPOSITES BY SUSPENSION AND EMULSION POLYMERIZATION Xinyu Huang; Brittain W J Akron,University PMMA-layered silicate nanocomposites were prepared by in-situ suspension polymerisation and emulsion polymerisation. Wide angle X-ray diffraction indicated that exfoliated structures could be obtained by both methods. The exfoliated structures remained stable during melt processing for samples prepared using organic modifiers which produced tethered polymer chains. Compared with a PMMA macrocomposite, these nanocomposites had glass transition temperatures which were up to 15C higher and thermal degradation temperatures up to 60C higher. 33 refs. USA

Accession no.819258 Item 247 Journal of Applied Polymer Science 80, No.12, 20th June 2001, p.2162-6 PREPARATION OF POLYETHYLENE OXIDE/ LIXV(2-DELTA)O(4-DELTA) NANOCOMPOSITES Xiao Y; Hu K A; Yu Q C; Wu R J Shanghai,Jiao Tong University

Item 245 Synthetic Metals 121, Nos.1-3, 15th March 2001, p.1737-8 ENHANCED QUANTUM EFFICIENCY IN POLYMER/LAYERED SILICATE NANOCOMPOSITE LIGHT-EMITTING DEVICES Tae-Woo Lee; O Ok Park; Jihyun Yoon; Jang-Joo Kim Korea,Advanced Institute of Science & Technology; Kwangju,Institute of Science & Technology

Nanocomposites of PEO and the above lithium vanadium oxide were prepared in aqueous solution. Characterisation of the nanocomposites using TGA, DSC, powder X-ray diffraction and FTIR spectroscopy showed that polymer chains intercalated inorganic host lamella and exhibited lattice expansion along the stacking direction of 4.2A. A possible model for the structure of the nanocomposite was also provided. It was suggested that the PEO between hosts had zig-zag type I conformation and that its crystallinity was restricted. 17 refs.

Poly(2-methoxy-5-(2'- ethyl-hexyloxy)-1,4-phenylene vinylene) (MEN-PPV) was blended with organo-clay with

CHINA

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Accession no.817849

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References and Abstracts

Item 248 Macromolecules 34, No.9, 24th April 2001, p.2992-9 CHAIN CONFORMATION AND CRYSTALLIZATION BEHAVIOR OF THE SYNDIOTACTIC POLYSTYRENE NANOCOMPOSITES STUDIED USING FOURIER TRANSFORM INFRARED ANALYSIS Hew-Der Wu; Chen-Rui Tseng; Feng-Chih Chang Taiwan,National Chiao-Tung University The effects of montmorillonite on the chain conformation and crystallisation of syndiotactic PS(s-PS) thin films were investigated using FTIR spectroscopy, X-ray diffraction and TEM. The clay was dispersed into the s-PS matrix using solution blending with particle size in the ranges 1 to 2 nm, or few tenths to 100 nm, depending on whether a surfactant was added or not. Upon adding clay, the chain conformation of s-PS tended to convert to TTTT from TTGG after drying because the highly dispersed clay overcame the energy barrier of chain conformation transformation. This phenomenon led to a change in a conventional mechanism of molecular packing for s-PS in the drying stage. During melt-crystallisation, clay played an important role in facilitating the formation of the thermodynamically favoured all-trans beta form crystal, particularly on the s-PS thin film samples. When the s-PS was melt-crystallised at a cooling rate of 1C/min from 320C, the highest absolute crystallinity of beta form up to 0.56 occurred in the clay dispersibility of few tenths to 100 nm in the s-PS matrix. Dispersibility was then 1 to 2 nm (0.49) and the final one was of pure s-PS (0.42). Clay evidently affected the chain conformation and crystallisation of s-PS. 30 refs. TAIWAN

Accession no.817720 Item 249 Journal of Polymer Science: Polymer Physics Edition 39, No.11, 1st June 2001, p.1137-46 INTERCALATED CLAY NANOCOMPOSITES: MORPHOLOGY, MECHANICS, AND FRACTURE BEHAVIOR Zerda A S; Lesser A J Massachusetts,University Intercalated nanocomposites of surface-modified montmorillonite clays in a glassy epoxy resin were prepared by crosslinking the epoxy with aliphatic diamine curing agents. The tensile modulus increased, but the intercalated morphology led to reductions in the ultimate strength and ductility. the macroscopic compressive behaviour was unchanged, but the failure mechanisms in compression differed from the unmodified epoxy resin. Improvements in fracture toughness values of 100% over unmodified resin were shown and the role of the morphology of the system in this improvement was discussed. 22 refs. USA

Accession no.817678

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Item 250 Journal of Applied Polymer Science 81, No.1, 5th July 2001, p.215-22 ORIENTATIONAL EFFECT OF MICA IN FUMED SILICA REINFORCED COMPOSITES Bokobza L; Nugay N Laboratoire de Physicochimie Struct.et Macromol.; Bogazici,University Mica filler was added to fumed silica-reinforced PDMS at loading levels of 1, 2, 5, 10 and 15 phr and the networks were crosslinked with dicumyl peroxide. the stress-strain properteis of the composite did not seem to be affected by the presence of the mica, but the swelling and orientational results showed interaction of the polymer chains with the filler particles. This produced additional crosslinks into the system and thus increased the network chain density. These interactions were not shown in the stress-strain curves, probably because the mica particles tended to orientate along the direction of stretch, thereby decreasing the viscosity of the system. 19 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; TURKEY; WESTERN EUROPE

Accession no.817666 Item 251 Macromolecular Rapid Communications 22, No.5, 26th March 2001, p.329-34 POLYETHYLENE NANOCOMPOSITE PREPARED VIA IN-SITU POLYMERIZATION Rong J; Jing Z; Li H; Sheng M Beijing,Research Institute of Petroleum Processing; Beijing,University of Chemical Technology Details are given of the preparation of an organic/ inorganic nanocomposite of PE by in-situ coordination polymerisation. The Ziegler-Natta catalyst was first supported on the surface of silicate nanowhiskers to subsequently initiate the polymerisation of ethylene on the surface of these nanowhiskers. Interactions between the nanowhiskers and the resin matrix are discussed. 34 refs. CHINA

Accession no.816185 Item 252 Macromolecular Rapid Communications 22, No.5, 26th March 2001, p.320-5 PREPARATION AND RHEOLOGICAL CHARACTERISTICS OF SOLVENT-CAST POLYETHYLENE OXIDE/ MONTMORILLONITE NANOCOMPOSITES Choi H J; Kim S G; Hyun Y H; Jhon M S Inha,University; Carnegie Mellon University PEO and montmorillonite clay nanocomposites were intercalated by a solvent casting method using chloroform as the cosolvent. The nanocomposites were characterised

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References and Abstracts

by an X-ray diffraction method. Rheological properties were investigated. 35 refs. KOREA; USA

Accession no.816183 Item 253 Chemistry of Materials 13, No.3, March 2001, p.1131-6 ENHANCEMENT OF CORROSION PROTECTION EFFECT IN POLYANILINE VIA THE FORMATION OF POLYANILINE-CLAY NANOCOMPOSITE MATERIALS Yeh J-M; Liou S-J; Lai C-Y; Wu P-C; Tsai T-Y Chung-Yuan,Christian University; Union Chemical Laboratories A series of nanocomposite materials consisting of emeraldine base of polyaniline and layered montmorillonite (MMT) clay are prepared by effectively dispersing the inorganic nanolayers of MMT clay in organic polyaniline matrix via in situ polymerisation. Organic aniline monomers are first intercalated into the interlayer regions of organophilic clay hosts and followed by one-step oxidative polymerisation. The as-synthesised polyaniline clay lamellar nanocomposite materials are characterised by IR spectroscopy, wide-angle powder X-ray diffraction and transmission electron microscopy. Polyaniline-clay nanocomposites (PCN) in the form of coatings with low clay loading on cold-rolled steel (CRS) are found much superior in corrosion protection over those of conventional polyaniline based on a series of electrochemical measurements of corrosion potential, polarisation resistance and corrosion current in 5 wt.% aqueous NaCl electrolyte. The molecular weights of polyaniline extracted from PCN materials and bulk polyaniline are determined by gel permeation chromatography. Effects of the material composition on the gas barrier property, thermal stability and mechanical strength of polyaniline along with PCN materials, in the form of both fine powder and free-standing film, are also studied by gas permeability measurements, differential scanning calorimetry, thermogravimetric analysis and dynamic mechanical analysis. 22 refs. TAIWAN

Accession no.816133 Item 254 Journal of Applied Polymer Science 80, No.11, 13th June 2001, p.2067-72 SYNTHESIS AND PROPERTIES OF ORGANOSOLUBLE POLYIMIDE/CLAY HYBRIDS Sheng-Huei Hsiao; Guey-Sheng Liou; Li-Ming Chang Tatung,University; I-Shou University A soluble polyimide was prepared from 7,7'-bis(4aminophenoxy)-4,4,4',4'-tetramethyl-2,2'-spirobichroman

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and 4,4'-hexafluoroisopropylidenediphthalic anhydride, and mixed with organo-modified montmorillonite or synthetic mica in N,N-dimethylacetamide. Transparent, flexible, and tough films were cast from the solutions and characterised by wide-angle X-ray scattering, transmission electron microscopy, thermomechanical analysis, thermogravimetric analysis and differential scanning calorimetry. The montmorillonite was more homogeneously dispersed than the mica. Both minerals gave a a reduction in thermal expansion coefficient and a slight increase in thermal stability. 14 refs. TAIWAN

Accession no.814360 Item 255 Polymer 42, No.13, 2001, p.5947-52 EXFOLIATION OF MONTMORILLONITE IN EPOXY In-Joo Chin; Thurn-Albrecht T; Ho-Cheol Kim; Russell T P; Jing Wang Massachusetts,University; Aspen Systems The structural evolution of epoxy-octadecyl amine treated montmorillonite nanocomposites was studied using small angle X-ray scattering and atomic force microscopy. When bisphenol A diglycidyl ether (DGEBA) was cured with equimolar or higher amounts of metaphenylenediamine (MPDA), only intercalated nanostructures were obtained. Exfoliated nanostructures were formed when DGEBA was cured with less than stoichiometric amounts of MPDA or when DGEBA was autopolymerised with montmorillonites. 28 refs. USA

Accession no.814024 Item 256 Polymer 42, No.13, 2001, p.5849-58 REINFORCEMENT AND ENVIRONMENTAL DEGRADATION OF NYLON-6/CLAY NANOCOMPOSITES Shelley J S; Mather P T; DeVries K L US,Air Force Research Laboratory; Connecticut,University; Utah,University The mechanism of reinforcement in nylon-6/clay nanocomposites was studied using tensile testing, dynamic mechanical analysis and FTIR spectroscopy. A 200% increase in modulus and a 175% improvement in yield stress was possible in extruded sheet of a 5 wt% clay nanocomposite. These improvements were attributed to the complexation of mid-chain carbonyl groups with the exfoliated clay lamellae. However, the incorporation of clay into nylon-6 did little to protect the material from exposure to atmospheric NO subscript 2, NO subscript 2 decreased the modulus and yield stress of moderately oriented nanocomposite sheet. The same rate of

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degradation occurred in the tensile modulus regardless of clay content or constrained volume. 55 refs. USA

Accession no.814012 Item 257 Polymer 42, No.13, 2001, p.5737-42 VISCOELASTICITY OF BIODEGRADABLE POLYMER BLENDS OF POLY(3HYDROXYBUTYRATE) AND POLY(ETHYLENE OXIDE) Park S H; Lim S T; Shin T K; Choi H J; Jhon M S Inha,University; Carnegie Mellon University The viscoelastic properties of biodegradable poly(3hydroxybutyrate)/PEO blends were studied by both steady shear and oscillatory experiments. The blends were miscible. The elastic and viscous properties from the steady shear experiments were qualitatively related to those measured by the oscillatory experiments, despite thermal degradation of the samples. 39 refs. SOUTH KOREA; USA

Accession no.813999 Item 258 Macromolecules 34, No.8, 10th April 2001, p.2735-8 CHARACTERIZATION OF THE DISPERSION OF CLAY IN A POLYETHERIMIDE NANOCOMPOSITE Morgan A B; Gilman J W; Jackson C L US,National Inst.of Standards & Technology Results are presented of TEM and X-ray diffraction studies of the dispersion of montmorillonite (sodium montmorillonite or montomorillonite treated with ndodecylamine ammonium salt or 12-aminododecanoic acid ammonium salt) in a polyetherimide nanocomposite. 17 refs. USA

Accession no.813465 Item 259 Macromolecular Rapid Communications 22, No.6, 5th April 2001, p.422-4 SYNTHESIS AND PROPERTIES OF POLYACRYLIC ACID/MICA SUPERABSORBENT NANOCOMPOSITE Lin J; Wu J; Yang Z; Pu M Huaqiao,University; Tianjin,University A novel polyacrylic acid/mica superabsorbent composite was synthesised by graft polymerisation reaction between partially neutralised acrylic acid and ultrafine mica powder. The influence of the neutralisation degree of acrylic acid and well as the amounts of mica and crosslinker on the absorbing properties are discussed. 8 refs. CHINA

Accession no.812301

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Item 260 Journal of Applied Polymer Science 80, No.4, 25th April 2001, p.592-603 SYNTHESIS AND LINEAR VISCOELASTIC BEHAVIOUR OF POLYAMIC ACIDORGANOCLAY HYBRID Kim J; Ahmed R; Lee S J Seoul,National University; Karachi,University The synthesis and rheology of polyamic acid-organoclay hybrids were studied to determine the molecular chain ordering and its relationship with clay particles in the prepolymer. The composite solution was mixed to the nanoscale level, and the extent of defoliation and phase separation were studied using X-ray diffraction, TEM, and DSC. Linear viscoelasticity was used to examine the influence of increasing extent of organoclay. 57 refs. KOREA; PAKISTAN

Accession no.811366 Item 261 Journal of Polymer Science: Polymer Chemistry Edition 39, No.7, 1st April 2001, p.986-96 FLAME-RETARDANT EPOXY RESINS: AN APPROACH FROM ORGANIC INORGANIC HYBRID NANOCOMPOSITES Hsiue G H; Liu Y L; Liao H H Taiwan,National Tsing Hua University; Chung Yuan University Phosphorus-containing epoxy-based epoxy-silica hybrid materials with a nanostructure are obtained from bis(3glycidyloxy)phenylphosphene oxide, diaminodiphenylmethane and tetraethoxysilane in the presence of the catalyst p-toluenesulphonic acid via an in situ sol-gel process. The silica, formed on a nanometer scale in the epoxy resin, is characterised with Fourier transform IR, NMR and scanning electron microscopy. The glass transition temperatures of the hybrid epoxy resins increase with silica content. The nanometer-scale silica shows an enhancement effect in improving the flame retardant properties of the epoxy resins. The phosphorus-silica synergistic effect on the limited oxygen index (LOI) enhancement is also observed with a high LOI value of 44.5. 36 refs. TAIWAN

Accession no.811204 Item 262 Macromolecules 34, No.6, 13th March 2001, p.1864-72 RHEOLOGY OF POLYPROPYLENE/CLAY HYBRID MATERIALS Solomon M J; Almusallam A S; Seefeldt K F; Somwangthanaroj A; Varadan P Michigan,University Hybrid materials of PP and amine-exchanged montmorillonite were prepared by melt mixing the

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References and Abstracts

components with maleic anhydride-functionalised PP as the compatibiliser. At inorganic loadings above 2.0%, the hybrid materials showed apparent low frequency plateaus in the linear viscoelastic moduli. The hybrid storage modulus depended on the chemistry of the amine exchanged into the clay. The amount of stress overshoot in flow reversal experiments was a function of the rest time allowed between the reversal. The transient stress in start-up of steady shear scaled with the applied strain. The results enabled the nanocomposite structure to be characterised, particularly at the mesoscopic level. 31 refs. USA

Accession no.811063 Item 263 Journal of Materials Science 36, No.4, 15th Feb.2001, p.871-7 PREPARATION AND PROPERTIES OF MONTMORILLONITE/ORGANO-SOLUBLE POLYIMIDE HYBRID MATERIALS PREPARED BY A ONE-STEP APPROACH Jun-Chao Huang; Zi-Kang Zhu; Xiao-Dong Ma; XueFeng Qian; Jie Yin Shanghai,Jiao Tong University Montmorillonite(MMT)/organo-soluble polyimide(PI) hybrids were prepared by a one-step approach. The organo-modified MMT was dispersed in a solution of diphenylether-3,3',4,4'-tetracarboxylic dianhydride and 4,4'-diamino-3,3'-dimethyldiphenylmethane. The solution polycondensation followed by a direct solution imidisation at 180C resulted in MMT/PI hybrid solutions. From wide-angle X-ray diffraction and TEM results, the MMT was basically exfoliated in the hybrid films cast from the solutions where the MMT content was below 5 wt %. Further increase in the MMT content led to severe aggregation. The properties of a MMT/PI hybrid were significantly dependent on the MMT content. When the MMT content was below 6 wt %, the introduction of the MMT led to strengthening and toughening of the PI matrix at the same time. The introduction of the MMT also resulted in improved thermal stability, a marked decrease in coefficient of thermal expansion, a slight increase in Tg and an increase in modulus. 34 refs. CHINA

Accession no.810892

octadecyl amine, was studied by TGA in comparison with that of non-exfoliated microcomposites based on organoclay, modified with protonated butyl amine. In the case of the nanocomposite, the temp. at which volatilisation occurred increased as compared with that of the microcomposite. Furthermore, the thermal oxidation process of the polymer was markedly slowed down in the nanocomposite with high char yield, both by a physical barrier effect enhanced by ablative reassembling of the silicate and by a chemical catalytic action due to the silicate and to the strongly acid sites created by thermal decomposition of the protonated amine silicate modifier. 10 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; ITALY; WESTERN EUROPE

Accession no.810866 Item 265 Chemistry of Materials 13, No.2, Feb.2001, p.250-2 INCLUSION OF POLY(TETRAMETHYL-PPHENYLENEDIAMINE DIHYDROCHLORIDE) INTO MOO3: A COOPERATIVE FORMATION ROUTE TO CONSTRUCT A POLYMER/MOO3 LAYERED STRUCTURE Shao Ke; Ma Ying; Cao Ya-an; Chen Zhao-hui; Ji Xuehai; Yao Jian-nian Beijing,Institute of Chemistry A polymer/molybdenum trioxide layered structure was obtained via a cooperative formation route by mixing the organic monomers with acidified ammonium molybdate. Molybdenum trioxide deposited as a hydrolysis product of ammonium molybdate when the monomers began to be polymerised. The polymer could be intercalated into molybdenum trioxide layers and its polymerisation would be made irreversible. The polymerisation was thus accelerated and could be conducted simultaneously with deposition of molybdenum trioxide. As a result, a precipitation of layered polymer/molybdenum trioxide could be obtained as soon as the starting materials were mixed. 14 refs. CHINA

Accession no.810486

Item 264 Macromolecular Rapid Communications 22, No.3, 23rd Feb.2001, p.176-80 THERMAL BEHAVIOUR OF POLY(PROPYLENE) LAYERED SILICATE NANOCOMPOSITES Zanetti M; Camino G; Reichert P; Muelhaupt R Torino,Universita; Freiburger Materialforschungszentrum; Albert-Ludwigs,University

Item 266 Chemistry of Materials 13, No.1, Jan.2001, p.222-6 EFFECT OF REACTIVITY OF ORGANICSMODIFIED MONTMORILLONITE ON THE THERMAL AND MECHANICAL PROPERTIES OF MONTMORILLONITE/POLYIMIDE NANOCOMPOSITES Horng-Long Tyan; Chyi-Ming Leu; Kung-Hwa Wei Taiwan,National Chiao Tung University

The thermal degradation behaviour of nanocomposites based on PP/organoclay, modified with protonated

Montmorillonite/polyimide (3,3',4,4'-benzophenone tetracarboxylic dianhydride-4,4'-oxydianiline, BTDA-ODA)

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117

References and Abstracts

nanocomposites displaying different morphological, thermal and mechanical characteristics were synthesised by using mono-, di- and trifunctional group swelling agent-modified montmorillonite and polyamic acid. It was found that the dispersion of silicate layers in BTDA-ODA shifted from intercalated to exfoliated structures when the number of functional groups of the swelling agent increased to three, as shown by X-ray diffraction and TEM studies. The improved morphology of the nanocomposites resulted in their enhanced mechanical and thermal properties. In particular, a 70% increase in Young’s modulus, a 50% increase in the maximum stress and a 30% reduction in the coefficients of thermal expansion were observed for the case of BTDA-ODA nanocomposites containing 5 wt % trifunctional group swelling agent-modified montmorillonite as compared with that of pure BTDA-ODA. 25 refs. TAIWAN

Accession no.810432

melt intercalation, with and without a compatibiliser. They were annealed and simultaneously characterised using high-temperature wide angle X-ray diffraction and controlled stress rheometry. The addition of a compatibiliser gave significantly higher creep resistance, and the creep resistance of the compatibilised composites increased with annealing time. From the creep data and microstructural studies it was concluded that a small amount of exfoliation occurred at the edges of the clay crystallites during extrusion and annealing. The zero shear viscosity of the compatibilised composites containing more than 3 wt% clay was at least 3 orders of magnitude greater than that of the matrix polymer and uncompatibilised composites. The increase in zero shear viscosity was not accompanied by an increase in flow activation energy. The rheological behaviour of the nanocomposites was attributed to large frictional interactions between the clay crystallites. 21 refs. INDIA

Item 267 Synthetic Metals 117, Nos.1-3, 15th Feb.2001, p.115-8 PHYSICAL CHARACTERIZATION OF POLYANILINE-NA SUPERSCRIPT +MONTMORILLONITE NANOCOMPOSITE INTERCALATED BY EMULSION POLYMERIZATION Kim B H; Jung J H; Kim J W; Choi H J; Joo J Korea,University; Inha,University Dodecyl benzene sulphonic acid doped polyaniline-Na superscript +-montmorillonite nanocomposite (PANDBSA-clay) was synthesised by emulsion polymerisation. The temperature dependence of the direct current (dc) conductivity of the nanocomposite followed a quasi onedimensional variable range hopping model. PAN-DBSA samples were in critical or metallic regime, whereas PANDBSA/clay samples were in insulating regime. The low conducting state of the nanocomposite samples resulted from the insertion of the clay layer which weakened the interchain interactions. X-ray photoelectron spectroscopy, EPR and X-ray diffraction studies showed that PANDBSA layers were inserted between the layers of Na superscript +-montmorillonite. 20 refs. SOUTH KOREA

Accession no.809665 Item 268 Macromolecules 34, No.4, 13th Feb.2001, p.852-8 RHEOLOGICAL STUDY ON THE KINETICS OF HYBRID FORMATION IN POLYPROPYLENE NANOCOMPOSITES Galgali G; Ramesh C; Lele A India,National Chemical Laboratory Nanocomposites of polypropylene containing an organically modified montmorillonite were prepared by

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Accession no.808647 Item 269 Journal of Polymer Science: Polymer Physics Edition 39, No.5, 1st March 2001, p.471-6 MONTMORILLONITE-BASED NANOCOMPOSITES OF POLYBENZOXAZOLE. SYNTHESIS AND CHARACTERIZATION Chang J-H; Park S-K; Ihn K J Kumoh,National University of Technology; Korea,Kangweon National University Polyamic acid was synthesised by means of lowtemperature solution polymerisation of dihydroxybenzidine and pyromellitic dianhydride in dimethylacetamide. The precursor polymer was heat treated at different temperatures to create a polybenzoxazole through a polyimide. Data are presented for mechanical, thermal and morphological properties of montmorillonite filled polybenzoxazoles. 18 refs. KOREA

Accession no.808072 Item 270 Macromolecules 34, No.2, 16th Jan.2001, p.337-9 NEW BIOMEDICAL POLY(URETHANE UREA)LAYERED SILICATE NANOCOMPOSITES Ruijian Xu; Manias E; Snyder A J; Runt J Pennsylvania,State University Poly(urethane urea)-alkylammonium-modified montmorillonite nanocomposite films were prepared. A significant reduction in gas permeability and an improvement in mechanical properties were observed for these layered films compared with neat poly(urethane urea). 19 refs. USA

Accession no.807933

© Copyright 2003 Rapra Technology Limited

References and Abstracts

Item 271 Journal of Polymer Science: Polymer Physics Edition 39, No.4, 15th Feb.2001, p.446-50 PP/CLAY NANOCOMPOSITES: A STUDY OF CRYSTALLIZATION AND DYNAMIC MECHANICAL BEHAVIOR Hambir S; Bulakh N; Kodgire P; Kalgaonkar R; Jog J P Pune,National Chemical Laboratory The crystallisation and dynamic mechanical properties of PP/clay nanocomposites were investigated. The composites exhibited disordered structures, as evidenced by the X-ray diffraction patterns. The thermal degradation temp. increased from 270 to about 330C on addition of the filler. DMA showed a significant improvement in the storage modulus. The intensity of the loss modulus peak was reduced, showing weak cooperative relaxations of PP in the PP/clay composites. A dramatic change in the crystalline morphology was observed in the PP/clay composites. The composites crystallised at a high temp. exhibited fibrous structures that grew with time. 13 refs. INDIA

Accession no.807384 Item 272 Polymer 42, No.7, 2001, p.3213-21 HYDROGEN BONDING AND MECHANICAL PROPERTIES IN SEGMENTED MONTMORILLONITE/POLYURETHANE NANOCOMPOSITES OF DIFFERENT HARD SEGMENT RATIOS Tien Y I; Wei K H Taiwan,National Chiao Tung University Hydrogen bonding in the hard segments of montmorillonite/PU nanocomposites of various hard segment ratios was found to decrease with increasing amount of montmorillonite, regardless of the hard segment ratios, but to reach plateau values at 5 wt % montmorillonite concentration. The maximal reductions of the hydrogen bonding in the PU nanocomposites ranged from 20 to 37%, depending on the hard segment ratios, as compared with that in the pure PU. The maximal strength and the EB of the PU nanocomposites increased significantly as compared with that of pristine PU and the maximal values occurred at 1 wt % montmorillonite concentration. 31 refs. TAIWAN

Accession no.807221 Item 273 Polymer 42, No.8, 2001, p.3399-408 THERMAL AND MECHANICAL PROPERTIES OF POLYIMIDE-CLAY NANOCOMPOSITES Agag T; Koga T; Takeichi T Toyohashi,University of Technology

© Copyright 2003 Rapra Technology Limited

The effect of the inclusion of a clay nanolayer on the mechanical and thermal properties of polyimides prepared from either 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA) and p-phenylene diamine (PDA) or pyromellitic dianhydride and 4,4'-oxydianiline. The curing behaviour, tensile and thermal properties of the nanocomposites are discussed as are the viscoelastic properties and linear coefficient of thermal expansion of the BPDA/PDA polyimide-clay nanocomposites. The effect of cold drawing on the BPDA/PDA polyimide clay nanocomposites is also evaluated and the amount of clay loading to provide nanocomposites with the best balance of properties established. 33 refs. JAPAN

Accession no.806138 Item 274 Antec 2000.Conference proceedings. Orlando, Fl., 7th-11th May, 2000, paper 710 DISPERSION OF NANOSCOPIC CLAY PARTICLES IN THERMOPLASTIC POLYMERS Barber G D; Carter C M; Moore R B Southern Mississippi,University (SPE) Alternative methods of clay dispersion, including melt processing, in-situ polymerisation and solution mixing, were evaluated for the dispersion of organically-modified montmorillonite nanoparticles in polymers, using ionomer compatibilisers. The polymer/ionomer combinations studied were: polyamide-6,6 (PA)/sulphonated PA, and poly(ethylene terephthalate) (PETP)/sulphonated PETP. The prepared nanocomposites were characterised by small angle X-ray scattering, transmission electron microscopy, differential scanning calorimetry, thermogravimetric analysis, dynamic mechanical analysis, and tensile testing. The incorporation of clay into PETP and PA gave partially intercalated structures, which were compatibilised by the introduction of the ionomers, with increasing ionic content and/or ionomer content giving increasing compatibility. Sulphonated PETP containing 10 mol% ionic functionality and sulphonated PA containing 2.3 mol% ionic functionality were effective compatibilisers for their respective homopolymers, giving a predominantly exfoliated morphology. The clay nanoparticles also acted as nucleating agents. 18 refs. USA

Accession no.805718 Item 275 ACS Polymeric Materials: Science and Engineering. Fall Meeting 2000. Volume 83. Washington, D.C., 20th-24th Aug.2000, p.105-6 FLAME RETARDANT PROPERTIES OF NOVOLAC PHENOLIC/BISOXAZOLINE AMENDED WITH AN EPOXY-TERMINATED SILOXANE AND CLAY NANOCOMPOSITE

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References and Abstracts

Dekar A; Stretz H; Koo J Southwest Texas,State University (ACS,Div.of Polymeric Materials Science & Engng.) It is determined whether pendant siloxanes and exfoliated nanocomposites provide interesting fire retardant properties to a phenolic system crosslinked with bisoxazoline and whether their action on the modulus, fire retardancy and impact strength is complementary. 7 refs. USA

Accession no.802845 Item 276 ACS Polymeric Materials: Science and Engineering. Fall Meeting 2000. Volume 83. Washington, D.C., 20th-24th Aug.2000, p.53-4 FLAMMABILITY OF POLYSTYRENE-CLAY NANOCOMPOSITES Morgan A B; Gilman J W; Harris R H; Jackson C L; Wilkie C A; Zhu J US,National Inst.of Standards & Technology; Marquette,University (ACS,Div.of Polymeric Materials Science & Engng.) Research in the area of condensed phase flame retardants for polymers usually builds upon technologies, such as metal hydroxides or phosphorus based materials. However, these materials tend to weaken mechanical properties while improving flammability resistance. No major new flame retardant technology has emerged in this area for quite some time. Polymer-clay nanocomposites have generated a great deal of interest lately due to improved mechanical and thermal properties. Also, they have improved flammability resistance while maintaining good mechanical properties, a key advantage over existing condensed phase flame retardants. It has been shown that polymer-clay nanocomposites have greatly reduced heat release rates. Further, polymers are observed which normally do not char, or leave any carbonaceous residue upon burning, produce char in the presence of clay. The flammability properties of styrene copolymers with phosphates and the ability to crosslink via Friedel-Crafts chemistry have been investigated. Friedel-Crafts technology is combined with clay to obtain an improved flame resistant PS. 4 refs. USA

Accession no.802816

The role of various quaternary ammonium-modified montmorillonites in epoxy/diamine nanocomposite formation is examined to further refine the criteria for selection of organic modifiers necessary to enable fabrication of thermoset resins containing nanoscale dispersions of inorganic phases. Utilisation of a hydroxylsubstituted quaternary ammonium modifier affords flexibility to combine both catalytic functionality, which increases the intragallery reaction rate, with enhanced miscibility toward both reagents. The rheological implications of these processing techniques are discussed with regards to using thermoset nanocomposites as a matrix in conventional fibre reinforced composites. The use of a low-boiling solvent to enhance mixability and processability of the initial mixtures is shown not to alter the structure or properties of the final nanocomposite. The use of autoclave techniques enables fabrication of highquality specimens containing up to 20 wt.% organically modified layered silicate. Finally, exfoliated and partially exfoliated epoxy/diamine nanocomposites are produced with enhanced heat-distortion temperature and increased flammability resistance. 28 refs. USA

Accession no.802545 Item 278 Advanced Materials 12, No.23, 1st Dec.2000, p.1835-9 POLYMERIC NANOCOMPOSITES FOR AUTOMOTIVE APPLICATIONS Garces J M; Moll D J; Bicerano J; Fibiger R; McLeod D G Dow Chemical Co.; Dow Automotive The use of nanocomposites for automotive applications is discussed in comparison with that of traditional materials. The key nanocomposite properties for automotive applications are described, including enhanced modulus and dimensional stability, higher heat distortion temp., improved scratch and mar resistance, and toughness and rheological properties. The production of polyolefin nanocomposites by melt processing of organoclays with modified polymers or by various insitu polymerisation methods is examined. The challenge of developing nanocomposites at competitive cost and with superior performance to replace metals and/or existing polymeric filler composites is considered. 22 refs. USA

Item 277 Chemistry of Materials 12, No.11, Nov.2000, p.3376-84 THERMOSET-LAYERED SILICATE NANOCOMPOSITES. QUATERNARY AMMONIUM MONTMORILLONITE WITH PRIMARY DIAMINE CURED EPOXIES Brown J M; Curliss D; Vaia R A US,Air Force,Wright-Patterson Base

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Accession no.800708 Item 279 Journal of Applied Polymer Science 79, No.2, 10th Jan.2001, p.289-94 NOVEL PREPARATION OF POLYIMIDE/CLAY HYBRID FILMS WITH LOW COEFFICIENT OF THERMAL EXPANSION Aijuan Gu; Feng-Chih Chang

© Copyright 2003 Rapra Technology Limited

References and Abstracts

Zhejiang,University; Taiwan,National Chiao Tung University

exfoliation of the clay as the epoxy resin was cured. The exfoliation mechanism is discussed. 18 refs.

A polyimide/clay hybrid nanocomposite (PI(PAAS)/CM) was developed from the polyamic acid salt of triethylamine and organomontmorillonite(CM) using a mixture solution of THF and methanol. For comparison, two other polyimide/clay hybrids derived from polyamic acid and CM in THF/methanol solution and DMAc solution (PI/CM(T/M) and PI/CM(DMAc), respectively) were also prepared. Dispersion of CM in polymer matrix, tensile properties and thermal expansion properties of the three hybrids were investigated. Results showed that PI(PAAS)/CM had the best dispersion of CM in polymer matrix, highest elongation and the lowest coefficient of thermal expansion values of all the prepared hybrids. In addition, PI/CM(T/M) had better dispersion of CM and lower coefficient of thermal expansion value than PI/ CM(DMAc). 23 refs.

CHINA

CHINA; TAIWAN

Accession no.800671 Item 280 Polymer 42, No.6, 2001, p.2685-8 DISPERSED STRUCTURE AND IONIC CONDUCTIVITY OF SMECTIC CLAY/ POLYMER NANOCOMPOSITES Okamoto M; Morita S; Kotaka T Toyota Technological Institute The correlation was examined between the internal structure and the ionic conductivity behaviour of lipophilised smectic clay/polymer nanocomposites having various dispersed morphologies of the clay layers. Both PS/clay and methyl methacrylate-acrylamide copolymer(99/1 mole ratio)/clay intercalated nanocomposites, which had finer dispersion of the clay layers, exhibited higher ionic conductivity than the other systems such as PMMA/clay nanocomposite with stacking layer structure. The conductivity of the nanocomposites was higher with increasing fineness of the dispersed morphology. 10 refs. JAPAN

Accession no.800651 Item 281 Journal of Polymer Science: Polymer Physics Edition 39, No.1, 1st Jan.2001, p.115-20 STUDY ON INTERCALATION AND EXFOLIATION BEHAVIOUR OF ORGANOCLAYS IN EPOXY RESIN Lu J; Ke Y; Qi Z; Yi X-S Hangzhou,Zhejiang University; Chinese Academy of Sciences The intercalation and exfoliation behaviour of organoclays in epoxy resins were studied through X-ray diffraction and DSC. A nanocomposite was obtained by the

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Accession no.799621 Item 282 Polymer 42, No.4, 2001, p.1621-31 SECONDARY STRUCTURE AND ELEVATED TEMPERATURE CRYSTALLITE MORPHOLOGY OF NYLON-6/LAYERED SILICATE NANOCOMPOSITES Lincoln D M; Vaia R A; Wang Z G; Hsiao B S Wright-Patterson Air Force Base; New York,State University Mesoscale (secondary) structure arising from association of layered silicates was quantified and its effect, together with that of constituent interactions, on elevated temp. crystalline morphology in nylon-6/montmorillonite nanocomposites was examined. Simultaneous small- and wide-angle X-ray scattering and diffraction methods were developed to provide detailed information on the secondary structure of the layered silicate and the structure of the crystalline polymer in the presence of the layered silicate. Ultra-long range order of the inorganic layers was observed at low-volume fractions. Elevated temp. (205C) crystallite morphology of the nylon-6 matrix depended on the secondary structure and interfacial interactions. Smaller, more disordered lamellae were observed in the in-situ polymerised nanocomposites, whereas larger, more ordered lamellae were observed in melt-processed nanocomposites. 67 refs. USA

Accession no.798940 Item 283 Polymer 42, No.4, 2001, p.1303-10 SYNTHESIS OF EPOXY-CLAY NANOCOMPOSITES: INFLUENCE OF THE NATURE OF THE CLAY ON STRUCTURE Kornmann X; Lindberg H; Berglund L A Lulea,University of Technology Epoxy resin-clay nanocomposites were synthesised using two montmorillonite clays(MMT) with different cationexchange capacities(CEC) with the aim of investigating the influence of the clay on the synthesis and structure of epoxy resin-clay nanocomposites. The dispersion of the 1 nm thick clay layers was investigated by X-ray diffraction(XRD) and TEM. Although XRD did not show any apparent order of the clay layers in the nanocomposite, TEM revealed parallel clay layers with interlamellar spacing of 90A and 110A for the higher and lower CEC clays, respectively, and the presence of remnant multiplets of non-exfoliated layers. A mechanism responsible for the influence of CEC on nanocomposite interlamellar

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References and Abstracts

spacing is discussed. The dispersion of the clay was investigated by SEM and found to be finer in the nanocomposites than in conventional composites, although the nanocomposites still had clay aggregates at the microscale rather than a monolithic structure. 29 refs.

interactions of an ordered polymeric guest do not preclude intercalation. The production of ultra-high performance polymer nanocomposites is thus possible. It was considered that the work showed a finite-size effect of the nematic state of thermotropic liquid crystalline polymers. 29 refs.

EUROPEAN UNION; SCANDINAVIA; SWEDEN; WESTERN EUROPE

USA

Accession no.798907 Item 284 Antec 2000.Conference proceedings. Orlando, Fl., 7th-11th May, 2000, paper 319 EFFECT OF LAYERED SILICATES ON THERMAL CHARACTERISTICS OF POLYCARBONATE NANOCOMPOSITES Severe G; Hsieh A J; Koene B E US,Army Research Laboratory; Triton Systems Inc. (SPE) Polycarbonate (PC)-matrix nanocomposites, containing layered silicates including phosphonium exchanged montmorillonites and synthetic clays containing C18alkyl side chains with or without additional tethering amino- or epoxy-groups, were characterised using differential scanning calorimetry and thermogravimetric analysis. The presence of the synthetic clays had little influence on the glass transition temperature (Tg) of the polymer, whilst those containing the montmorillonitebased fillers exhibited a very slight decrease in Tg. An endotherm was observed at approximately 50 C. The thermal stability was adversely affected by the addition of the synthetic clays, the nanocomposites containing 7.5% and 10% of the C18-synthetic clay exhibiting a twostep degradation, the second step occurring at a temperature slightly higher than the onset degradation temperature of pure PC. The nanocomposites containing exchanged montmorillonites exhibited higher thermal stability than those containing synthetic clays, the onset temperature of thermal degradation being slightly higher than that of pure PC. 7 refs. USA

Accession no.798501 Item 285 Polymer 42, No.3, 2001, p.1281-5 LIQUID CRYSTAL POLYMER NANOCOMPOSITES: DIRECT INTERCALATION OF THERMOTROPIC LIQUID CRYSTALLINE POLYMERS INTO LAYERED SILICATES Vaia R A; Giannelis E P US,Air Force Research Laboratory; Cornell University Two ordered media such as organically modified layered silicates and thermotropic liquid-crystalline polymers were demonstrated to have reversible intercalation in the nematic state. The decreased diffusivities and intermolecular

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Accession no.798402 Item 286 Polymer 42, No.3, 2001, p.1201-6 DISPERSED STRUCTURE CHANGE OF SMECTIC CLAY/POLY(METHYL METHACRYLATE) NANOCOMPOSITES BY COPOLYMERIZATION WITH POLAR COMONOMERS Okamoto M; Morita S; Kim Y H; Kotaka T; Tateyama H Toyota Technological Institute; Kyushu,National Industrial Research Institute Methyl methacrylate was copolymerised, using an in-situ method, with a small amount of polar comonomers such as N,N-dimethylaminopropyl acrylamide, N,Ndimethylaminoethyl acrylate and acrylamide clay/ copolymer-based nanocomposites were produced using lipophilised smectic clay. The dispersion and intercalation spacing were investigated using transmission electron microscopy and X-ray diffraction techniques. Inclusion of the clay gave a lower modulus due to the large aspect ratio of the dispersed clay particles. 6 refs. JAPAN

Accession no.798392 Item 287 Polymer 42, No.3, 2001, p.1095-100 INFLUENCE OF NANOFILLERS ON THE DEFORMATION PROCESS IN LAYERED SILICATE/POLYAMIDE-12 NANOCOMPOSITES Kim GG-M; Lee D-H; Hoffmann B; Kressler J; Stoppelmann G Eindhoven,University of Technology; Kyungpook,National University; AlbertLudwigs,University; Halle,Martin-Luther-Universitat Injection moulded polymer nanocomposites from a synthetic layered silicate and polyamide-12, were studied for their morphology and the influence on local deformation processes of the nanofiller particles. The dispersion of the silicate and the orientation of the lamellae were seen in the complexity of the deformation mechanisms. These latter mechanisms influence the macroscopic properties of the nanocomposite. The main deformation mechanism is the formation of microvoids within the layered silicate structure. 42 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; NETHERLANDS; SOUTH KOREA; SWITZERLAND; WESTERN EUROPE

Accession no.798382

© Copyright 2003 Rapra Technology Limited

References and Abstracts

Item 288 Polymer 42, No.3, 2001, p.1083-94 NYLON 6 NANOCOMPOSITES BY MELT COMPOUNDING Cho J W; Paul D R Austin,University of Texas Nanocomposites from nylon 6 and organoclay were prepared by direct melt compounding using a conventional twin-screw extruder. The morphology and mechanical properties of the nanocomposites were determined and a comparison made with similar materials produced by an in situ polymerisation technique. 53 refs. USA

Accession no.798381 Item 289 Polymer 42, No.3, 2001, p.873-7 POLY(ETHERIMIDE)/MONTMORILLONITE NANOCOMPOSITES PREPARED BY MELT INTERCALATION: MORPHOLOGY, SOLVENT RESISTANCE PROPERTIES AND THERMAL PROPERTIES Huang J-C; Zhu Z-K; Qian X-F; Sun Y-Y Shanghai,Jiao Tong University By melt-blending in an internal mixer an organic modified montmorillonite nanocomposite with a thermoplastic poly(etherimide) was prepared. X-ray diffraction was used to determine the dispersion of the montmorillonite layers within the poly(etherimide) matrix. The nanocomposites which resulted were found to exhibit a substantial glass transition temperature and thermal decomposition temperature increase, coupled with a dramatic solvent uptake compared to the original poly(etherimide). 24 refs. CHINA

Accession no.798360 Item 290 Journal of Polymer Science: Polymer Physics Edition 38, No.22, 15th Nov.2000, p.2873-8 MECHANICAL PROPERTIES OF CLAYPOLYIMIDE NANOCOMPOSITES VIA ODAMODIFIED ORGANOCLAY Tyan H-L; Wei K-H; Hsieh T-E Taiwan,National Chiao Tung University Clay-polyimide nanocomposites were synthesised from modified montmorillonite and polyamic acid. The layered silicates of organoclay were intercalated by polyimide and examined by X-ray diffraction and TEM. Tensile properties of the nanocomposites were investigated. 25 refs. TAIWAN

Accession no.797643

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Item 291 Polymer Preprints. Volume 40. Number 2. August 1999. Conference proceedings. New Orleans, La., August 1999, p.813-4 SYNTHESIS AND ELECTRORHEOLOGICAL CHARACTERISATION OF POLYANILINE-NA+MONTMORILLONITE CLAY SUSPENSIONS Chai H J; Kim J W; Kim S G; Jhon M S Inha,University; Carnegie-Mellon University (ACS,Div.of Polymer Chemistry) Electrorheological (ER) fluids are fluids whose rheological properties depend strongly and reversibly on an applied electric field. It is generally accepted that the ER effect of these suspensions is a result of particle fibrillation (strings of particles) oriented along the electric field direction. In general, ER fluids can solidify in (the order of) milliseconds and fluidise under applied deformation that destroys the chain structure formed by the particles. SAN-clay nanocomposite particles and their ER properties have recently been studied. The Na+exchanged MMT sample was emulsion polymerised with SAN in the presence of potassium persulphate and sodium lauryl sulphate. A novel investigation of the ER characteristics for suspensions of PANI-clay composite particles with intercalation structure is presented. 15 refs. USA

Accession no.797275 Item 292 Macromolecular Rapid Communications 21, No.16, 14th Nov.2000, p.1136-9 EXPANSION DISTRIBUTION OF BASAL SPACING OF THE SILICATE LAYERS IN POLYANILINE/NA+-MONTMORILLONITE NANOCOMPOSITES MONITORED WITH XRAY DIFFRACTION Lee D; Lee S-H; Char K; Kim J Seoul,National University; Sung Kyun Kwan University The preparation of polyaniline/sodium montmorillonite nanocomposites by in-situ intercalation polymerisation of aniline into sodium montmorillonite is described. The expansion distribution of basal spacing of the silicate layers in the nanocomposite upon increasing polyaniline content is demonstrated by an analysis of the square of the full-width at half-maximum of X-ray diffraction patterns and the relationship between the change in the basal spacing of the silicate layers to the degree of hydrogen bonding between the polyaniline and silicate basal surface in a confined geometry is discussed. 9 refs. KOREA

Accession no.795889 Item 293 Macromolecules 33, No.20, 3rd Oct.2000, p.7219-22

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References and Abstracts

SHEAR ORIENTATION OF VISCOELASTIC POLYMER-CLAY SOLUTIONS PROBED BY FLOW BIREFRINGENCE AND SANS Schmidt G; Nakatani A I; Butler P D; Karim A; Han C C US,National Inst.of Standards & Technology Results are presented of an investigation of the influence of shear on the structure of a highly viscoelastic synthetic hectorite-type clay-PEO aqueous solution, carried out by means of flow birefringence and small-angle neutron scattering measurements. The clay particles were composed of platelets of high purity and uniform crystallite size. The results obtained indicated that the polymer chains must be adsorbed to the clay particles and that flow was sufficiently strong to enhance and maintain a continuous increase in the orientation of the polymer-clay system. 37 refs. USA

Accession no.794470 Item 294 Polymer Bulletin 45, No.2, Sept.2000, p.183-90 EFFECTS OF ACRYLONITRILE CONTENT ON THE PROPERTIES OF CLAY-DISPERSED POLY(STYRENE-CO-ACRYLONITRILE) COPOLYMER NANOCOMPOSITE Moon Bae Ko Korea,Institute of Science & Technology Clay-dispersed nanocomposites were prepared by melt mixing of poly(styrene-co-acrylonitrile) copolymers with different acrylonitrile contents with two different kinds of organophilic clay, using a twin-screw extruder. The dispersion behaviour of 10 Angstrom-thick silicate layers was studied by TEM and X-ray diffraction. The acrylonitrile component of the copolymers accelerated intercalation of the copolymers into the galleries of the silicate layers modified with either dimethyl hydrogenated-tallow (2-ethylhexyl)ammonium or methyl tallow bis-2-hydroxyethylammonium. The reaction mechanisms which occurred were discussed. 9 refs. KOREA

Accession no.794373 Item 295 Journal of Applied Polymer Science 78, No.11, 9th Dec.2000, p.1918-22 PREPARATION AND MECHANICAL PROPERTIES OF POLYPROPYLENE-CLAY HYBRIDS BASED ON MODIFIED POLYPROPYLENE AND ORGANOPHILIC CLAY Hasegawa N; Okamoto H; Kato M; Usuki A Toyota Central R & D Laboratories Inc. PP-clay hybrid composites were prepared by melt blending of maleic anhydride-modified PP and

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organophilic clay. The silicate layers of the clay in these hybrids were exfoliated and dispersed to the monolayers. The hybridisation of the clay in PP was achieved with modified PP with a small amount of maleic anhydride groups. The tensile modulus of the hybrid composite with 5 wt % clay was 1.9 times higher than that of the matrix resin at 25C. The dynamic storage moduli of the composites were also higher than those of the modified PP. The moduli were 2.5 times higher than that of the matrix resin at 60C. 20 refs. JAPAN

Accession no.793642 Item 296 Journal of Applied Polymer Science 78, No.11, 9th Dec.2000, p.1879-83 PREPARATION AND CHARACTERIZATION OF RUBBER-CLAY NANOCOMPOSITES Yizhong Wang; Liqun Zhang; Chunhong Tang; Dingsheng Yu Beijing,University of Chemical Technology Styrene-butadiene rubber/clay nanocomposites were prepared by two different methods and characterised by TEM and X-ray diffraction(XRD). The TEM showed that clay had been dispersed to one or several layers. The XRD showed that the basal spacing in the clay was increased. Some macromolecules were found to intercalate to the clay layer galleries. The clay layer could be uniformly dispersed in the rubber matrix on the nanometer level. The mechanical tests showed that the nanocomposites had good mechanical properties. Some properties exceeded those of rubber reinforced with carbon black. 10 refs. CHINA

Accession no.793637 Item 297 Journal of Applied Polymer Science 78, No.11, 9th Dec.2000, p.1873-8 MORPHOLOGY AND MECHANICAL PROPERTIES OF CLAY/STYRENE-BUTADIENE RUBBER NANOCOMPOSITES Liqun Zhang; Yizhong Wang; Yiqing Wang; Yuan Sui; Dingsheng Yu Beijing,University of Chemical Technology Clay/SBR nanocomposites were prepared by mixing the SBR latex with a clay/water dispersion and coagulating the mixture. The structure of the dispersion of clay in the SBR was studied by TEM. The mechanical properties of the clay/SBR nanocomposites with different contents of clay filler were studied. The results showed that the main structure of the dispersion of clay in the SBR was a layer bundle whose thickness was 4 to 10 nm and its aggregation formed by several or many layer bundles. Some mechanical properties of clay/SBR nanocomposites exceeded those of carbon black/SBR composites and they were better than those of clay/SBR composites produced

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References and Abstracts

by directly mixing clay with SBR through regular rubber processing methods. 6 refs. CHINA

Accession no.793636 Item 298 Chemistry of Materials 12, No.10, Oct. 2000, p.2977-83 MORPHOLOGY AND CURING BEHAVIOURS OF PHENOLIC RESIN-LAYERED SILICATE NANOCOMPOSITES PREPARED BY METAL INTERCALATION Choi M H; Chung I J; Lee J D Korea,Advanced Institute of Science & Technology; Suwon,University The metal intercalation and curing behaviour of phenolic resin were investigated by use of layered silicates as curing agents. Cured phenolic resin-layered silicate nanocomposites were prepared by the sequential process of intercalation and curing and by the simultaneous process of mixing and curing. 51 refs.

Dispersions of intercalated clay(VDAC-MMT) in styrene monomer formed gels. Shear thinning behaviour of the gels was observed via rheological measurements. PS-clay nanocomposites were prepared by free radical polymerisation of styrene containing dispersed organophilic MMT. Exfoliation of MMT in PS matrix was achieved as revealed by X-ray diffraction and TEM. The exfoliated nanocomposites had higher dynamic modulus and higher decomposition temp. than pure PS. 23 refs. USA

Accession no.791290 Item 301 Kobunshi Ronbunshu 57, No.7, 2000, p.433-9 Japanese CRYSTAL STRUCTURE OF NYLON 6/ INORGANIC LAYERED SILICATE NANOCOMPOSITE FILM Fujimoto K; Yoshikawa M; Katahira S; Yasue K Unitika Ltd.

Details are given of the preparation of PVAL/sodium montmorillonite nanocomposites. Data are presented for thermal, mechanical and optical properties of pure PVAL and the nanocomposites. 25 refs.

Crystal structure of nanocomposite films composed of nylon 6 matrix and synthetic layered silicate as a filler (NCN 6) is analytically investigated using IR spectroscopy, differential scanning calorimetry (DSC) and X-ray scattering/diffraction. IR spectra indicate that the silicate layers have planar orientation, and Avrami indices obtained from isothermal DSC measurement indicate that the spherulites in the NCN 6 films are crystallised in a twodimensional fashion. Moreover, X-ray analysis reveals that the fibre axis of gamma-nylon 6 crystallites is parallel to the film surface in contrast with the pure nylon 6 crystallites, which are randomly oriented. As a result, for the NCN 6 films it is considered that the two-dimensional spherulites grown out of silicate layers have planar orientation parallel to the film surface, and this model is able to interpret qualitatively the high gas barrier of NCN 6 films. 10 refs.

USA

JAPAN

Accession no.792488

Accession no.790170

Item 300 Polymer 42, No.2, 2001, p.807-13 POLYMER-CLAY NANOCOMPOSITES: EXFOLIATION OF ORGANOPHILIC MONTMORILLONITE NANOLAYERS IN POLYSTYRENE Fu X; Qutubuddin S Case Western Reserve University

Item 302 Macromolecular Materials and Engineering Vols.280/281, Aug.2000, p.76-9 POLYOLEFIN-CLAY HYBRIDS BASED ON MODIFIED POLYOLEFINS AND ORGANOPHILIC CLAY Hasegawa N; Okamoto H; Kawasumi M; Kato M; Tsukigase A; Usuki A Toyota Central R & D Laboratories Inc.

Vi n y l b e n z y l d i m e t h y l d o d e c y l a m m o n i u m chloride(VDAC), a polymerisable cationic surfactant, was synthesised and used for functionalisation of montmorillonite(MMT) and preparation of exfoliated PSclay nanocomposites. Organophilic MMT was prepared by cationic exchange between inorganic ions of MMT and ammonium cations of VDAC in an aqueous medium.

Details are given of the preparation of polyolefin-clay hybrids by using maleic anhydride modified polyolefins and organophilic clay during melt blending. The silicate layers of the clay were exfoliated and homogeneously dispersed at the monolayers in the hybrids. 17 refs.

KOREA

Accession no.792491 Item 299 Chemistry of Materials 12, No.10, Oct. 2000, p.2943-9 STRUCTURE AND PROPERTIES OF POLYVINYL ALCOHOL/NA MONTMORILLONITE NANOCOMPOSITES Strawhecker K E; Manias E Pennsylvania,State University

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JAPAN

Accession no.789222

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Item 303 Chemistry of Materials 12, No.7, July 2000, p.1866-73 FLAMMABILITY PROPERTIES OF POLYMERLAYERED SILICATE NANOCOMPOSITES. POLYPROPYLENE AND POLYSTYRENE NANOCOMPOSITES Gilman J W; Jackson C L; Morgan A B; Harris R; Manias E; Giannelis E P; Wuthenow M; Hilton D; Phillips S H US,National Inst.of Standards & Technology; Pennsylvania,State University; Cornell University; US,Air Force Research Laboratory A continuing study of the mechanism of flammability reduction of polymer-layered silicate nanocomposites yields results for polypropylene-graft-maleic anhydride and polystyrene-layered-silicate nanocomposites using montmorillonite and fluorohectorite. Cone calorimetry is used to measure the heat release rate and other flammability properties of the nanocomposites, under well-controlled combustion conditions. Both the polymerlayered silicate nanocomposites and the combustion residues are studied by transmission electron microscopy and X-ray diffraction. Evidence is found for a common mechanism of flammability reduction. It is also found that the type of layered silicate, nanodispersion and processing degradation have an influence on the flammability reduction. 35 refs. USA

Accession no.786801 Item 304 Chemistry of Materials 12, No.8, Aug.2000, p.2168-74 EFFECT OF LAYER CHARGE ON THE INTERCALATION OF POLYETHYLENE OXIDE IN LAYERED SILICATES. IMPLICATIONS ON NANOCOMPOSITE POLYMER ELECTROLYTES Bujdak J; Hackett E; Giannelis E P Cornell University The effect of layer charge on the intercalation of PEO was investigated using a series of reduced-charge montmorillonites and smectites with varying layer charge. Experimental data were confirmed using molecular simulations. 36 refs. USA

Accession no.786603 Item 305 Journal of Macromolecular Science B B39, No.4, 2000, p.545-59 FIBRE STRUCTURE FORMATION IN HIGHSPEED MELT SPINNING OF POLYAMIDE 6/ CLAY HYBRID NANOCOMPOSITE Giza E; Ito H; Kikutani T; Okui N

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Tokyo,Institute of Technology Nanocomposites of polyamide 6 containing 2 and 5 wt.% of clay were melt spun at take-up velocities from 1 to 5 km/mm and structure formation during this high-speed spinning investigated. The influence of clay on fibre structure formation and of clay content, spinning conditions and structure on the mechanical properties of the as-spun filaments were evaluated. Investigative techniques employed included birefringence and density measurements, DSC, wide-angle X-ray diffraction, measurement of fibre shrinkage after spinning and tensile testing. The results obtained are compared with those for polyamide 6 spun at take-up speeds of from 1 to 7 km/ min. 27 refs. JAPAN

Accession no.786359 Item 306 Journal of Applied Polymer Science 77, No.13, 23rd Sept.2000, p.2948-56 WATER-DISPERSIBLE NANOCOMPOSITES OF POLYANILINE AND MONTMORILLONITE Biswas M; Ray S S Calcutta,Presidency College A nanodimensional composite of polyaniline and montmorillonite(MMT) was obtained by oxidative polymerisation of aniline in aqueous medium in the presence of ammonium peroxodisulphate and MMT. The composite could be obtained as a stable dispersion in water in the presence of a polymeric stabiliser, poly(Nvinyl pyrrolidone), under selective conditions. The bulk conductivities of these dispersions could be increased by increasing the loading of polyaniline on the composite by varying amounts of aniline or oxidant in the initial feed. 22 refs. INDIA

Accession no.786223 Item 307 Polymer 41, No.24, 2000, p.8557-63 PROPERTY AND FORMATION MECHANISM OF UNSATURATED POLYESTER-LAYERED SILICATE NANOCOMPOSITE DEPENDING ON THE FABRICATION METHODS Suh D J; Lim Y T; Park O O Korea,Advanced Institute of Science & Technology In order to study the properties and formation mechanism of unsaturated polyester (UP)/montmorillonite (MMT) layered nanocomposites, samples were prepared using simultaneous mixing or sequential mixing. In sequential mixing, a mixture of UP and organophilic-treated MMT were prepared and then a styrene monomer was added to the pre-intercalates of UP/MMT for various mixing times. The structures of the nanocomposites were studied by X-

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References and Abstracts

ray diffraction and TEM and the formation mechanism by dynamic mechanical thermal analysis, solution rheometry and melt rheometry. The formation mechanism was discussed and the thermal rheological and dynamic mechanical properties of the nanocomposites prepared by the two different methods were compared. Based on the mechanism of nanocomposite formation, the authors were able to increase the crosslink density and degree of dispersion in UP/MMT nanocomposites. 21 refs. SOUTH KOREA

Accession no.784916 Item 308 Fire & Materials 24, No.2, March/April 2000, p.85-90 INVESTIGATION OF FLAME RETARDANCY IN EVA Camino G; Sgobbi R; Zaopo A; Colombier S; Scelza C Torino,Universita; Pirelli Cavi e Sistemi SpA Strategies for fire retarding EVA in electrical cable insulation by means of halogen-free systems are explored. Attempts to increase char yield, promoting crosslinking of double bonds either created by deacetylation of vinyl acetate units or by dehydrogenation of ethylene sequences in EVA, are carried out. Pd catalysed dehydrogenation is unsuccessful, whereas oxidative dehydrogenation seems promising as shown by using thermally decomposing KMnO4. On the other hand, organic peroxides fail to increase the rate of crosslinking of deacetylated units. Better results are obtained with the addition to EVA of an intumescent system which is a combination of melamine phosphate and phosphate-phosphonate substituted trimethylamine. EVA is shown to play a substantial role in the intumescence phenomenon. 11 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; ITALY; WESTERN EUROPE

Accession no.784094 Item 309 Colloid & Polymer Science 278, No.7, July 2000, p.629-36 RHEOLOGY OF NANOCOMPOSITES BASED ON LAYERED SILICATES AND POLYAMIDE-12 Hoffman B; Kressler J; Stoppelmann G; Friedrich C; Kim G-M Freiburger Materialforschungszentrum; AlbertLudwigs,University; Halle,Martin-Luther-Universitat; EMS-Chemie AG; Eindhoven,University of Technology Nanocomposites based on polyamide-12 (PA-12) and layered silicates are synthesised and analysed with respect to their morphological and rheological properties. Transmission electron microscopy shows the fine dispersion of silicate layers in a PA-12 matrix. Different swelling agents for the clay (protonated aminododecanoic acid or water) are used. This allows the molar mass of

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PA-12 to be controlled during the preparation of the nanocomposites. When aminododecanoic acid is used as a swelling agent, the exfoliated silicate layers are chemically bonded to the matrix, whereas the use of water as a swelling agent leads to exfoliated silicate layers well dispersed in the polymer matrix without tethered polymer chains. The rheological behaviour of the nanocomposites differs extremely from that of the pure PA-12 matrices. A qualitative description of the rheology of these nanocomposites is provided. 40 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; NETHERLANDS; SWITZERLAND; WESTERN EUROPE

Accession no.784025 Item 310 Macromolecules 33, No.14,11th July 2000, p.5227-34 STABILITY OF DIBLOCK COPOLYMER/ LAYERED SILICATE NANOCOMPOSITE THIN FILMS Limary R; Swinnea S; Green P F Texas,University The stability of thin film nanocomposites on silicon substrates, formed from mixtures of a symmetric diblock copolymer blended with layered silicate nanocomposites, was investigated using a combination of optical microscopy, atomic force microscopy and X-ray diffraction. The two cases examined were PS-b-PMMA blended with montmorillonite modified with stoichiometric amounts of alkylammonium surfactant chains (OLS(S)) and PS-bPMMA blended with montmorillonite modified with excess alkylammonium (OLS(E)). While the phase behaviour of the OLS(S)/copolymer was similar to that observed in bulk studies, that of the OLS(E)/copolymer system was different. It was shown that an exchange occurred between surfactant molecules in the OLS(E) system with copolymer chains and that the surfactant molecules formed a separate layer on the substrate, resulting in a destabilisation of the film. 27 refs. USA

Accession no.783251 Item 311 ACS Polymeric Materials: Science & Engineering.Spring Meeting 2000.Volume 82.Conference proceedings. San Francisco, Ca., 26th-30th March 2000, p.286-7 SYNTHESIS AND CHARACTERIZATION OF NANOCOMPOSITES BASED ON LAYERED SILICATES AND POLYAMIDE-12 Hoffmann B; Kressler J; Stoppelmann G Freiburg,University; Halle,Martin-Luther-Universitat; EMS-Chemie AG (ACS,Div.of Polymeric Materials Science & Engng.) Nanocomposites were prepared by the polycondensation of omega-aminododecanoic acid (ADA) containing a

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variety of exfoliated or intercalated layered silicates, to investigate the influence of swelling conditions on the rheological and mechanical properties. The silicate materials were prepared by swelling synthetic silicates (using protonated ADA) or bentonite clay (using protonated ADA or water). The mechanical properties of the polyamide-12 (PA-12) nanocomposites were improved, whilst maintaining the same notched impact toughness, compared with PA-12. Enhanced dimensional stability, barrier resistance, thermal stability and flame resistance were also observed. The nanocomposites exhibited complex rheological behaviour. The slopes of the master curves of the shear storage modulus and the loss modulus in the terminal region were considerably lower than those of the matrix polymer, attributed to the formation of a superstructure in the molten state. 7 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; SWITZERLAND; WESTERN EUROPE

Accession no.783159 Item 312 ACS Polymeric Materials: Science & Engineering.Spring Meeting 2000.Volume 82.Conference proceedings. San Francisco, Ca., 26th-30th March 2000, p.278-9 PROCESSING AND MORPHOLOGY IN THERMOSETTING LAYERED SILICATE NANOCOMPOSITES Brown J M; Curliss D B; Vaia R A US,Air Force Research Laboratory (ACS,Div.of Polymeric Materials Science & Engng.)

the molecular level by covalent attachment of polyhedral oligomeric silsesquioxane (POSS) were compared with those of cured epoxy reinforced with exfoliated clay (alkylammonium ion-exchange montmorillonite). The glass transition temperature (Tg) of the POSS-reinforced networks increased with increasing POSS content, whilst the Tg of the clay system was independent of the clay content. Both reinforcements slowed the motion of network junctions and the small strain stress relaxation increased compared with the un-reinforced networks. It was concluded that to improve thermal, viscoelastic, and mechanical properties, reinforcements at the molecular level (POSS nanostructure) and at the microscopic level (exfoliated or intercalated clays) should be used. 6 refs. USA

Accession no.783134 Item 314 ACS Polymeric Materials: Science & Engineering.Spring Meeting 2000.Volume 82.Conference proceedings. San Francisco, Ca., 26th-30th March 2000, p.208-9 THERMAL AND THERMO-MECHANICAL PROPERTIES OF PMMA NANOCOMPOSITES Bandyopadhyay S; Giannelis E P; Hsieh A J Cornell University; US,Army Research Laboratory (ACS,Div.of Polymeric Materials Science & Engng.)

By combining new surface modifiers, low boiling point processing aids and autoclave processing, both exfoliated and partially exfoliated epoxies containing high loadings of layered silicates (20 wt%) were reproducibly fabricated. The structures were produced when a quaternary amine modified layered silicate was combined with a primary amine cured epoxy. With some compositions, the organic modifier served as a compatibiliser for the monomers as well as acting as a catalyst for the epoxy diamine cure. 10 refs.

Nanocomposites were prepared by the emulsion polymerisation of methyl methacrylate in the presence of sodium montmorillonite (MMT) or fluorohectorite (FH), and characterised by X-ray diffraction, transmission electron microscopy, thermogravimetric analysis, and dynamic mechanical analysis at a fixed frequency of 1 Hz from room temperature to 150 C. The composites exhibited enhanced thermal stability, storage moduli and glass transition temperatures relative to the polymer. The higher storage modulus in the rubbery regime of the MMT composite compared with the FH composite was attributed to the greater proportion of bound polymer. 29 refs.

USA

USA

Accession no.783155

Accession no.783120

Item 313 ACS Polymeric Materials: Science & Engineering.Spring Meeting 2000.Volume 82.Conference proceedings. San Francisco, Ca., 26th-30th March 2000, p.235-6 EPOXY-POSS AND EPOXY-CLAY NANOCOMPOSITES: THERMAL AND VISCOELASTIC COMPARISONS Lee A; Lichtenhan J D; Reinerth W A Michigan,State University; Hybrid Plastics (ACS,Div.of Polymeric Materials Science & Engng.)

Item 315 Polymer 41, No.19, 2000, p.7083-90 POLYBENZOXAZINE-MONTMORILLONITE HYBRID NANOCOMPOSITES: SYNTHESIS AND CHARACTERISATION Agag T; Takeichi T Toyohashi,University

The thermal properties, viscoelastic properties and physical ageing of cured epoxy networks reinforced at

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Polybenzoxazine-clay hybrid nanocomposites were produced from a polybenzoxazine precursor and montmorillonite surface treated with octyl, dodecyl or stearyl ammonium chloride surfactants. The curing behaviour of the precursor in the presence of dispersed

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References and Abstracts

montmorillonite was investigated using IR spectroscopy and DSC and dispersion of montmorillonite in the polybenzoxazine matrix was confirmed by X-ray diffraction. The viscoelastic and thermal properties of the nanocomposites were determined by DMA and dynamic TGA and the results obtained compared with those for pristine polybenzoxazine. 68 refs. JAPAN

Accession no.781319 Item 316 Journal of Polymer Science: Polymer Physics Edition 38, No.12, 15th June 2000, p.1595-604 NANOSTRUCTURE AND PROPERTIES OF POLYSILOXANE-LAYERED SILICATE NANOCOMPOSITES Burnside S D; Giannelis E P New York,Bard Hall Using polysiloxane layered silicate nanocomposites the relationship between their nanostructure and properties has been investigated. The nanocomposites were synthesised, and characterised. Solvent swelling, and bound rubber determinations were made. The crystalline and glass transition characteristics were evaluated, as were their viscoelastic properties. 40 refs. USA

Accession no.780589 Item 317 Macromolecules 33, No.10, 16th May 2000, p.3739-46 LINEAR VISCOELASTICITY OF DISORDERED POLYSTYRENE-POLYSTYRENE BLOCK COPOLYMER BASED LAYERED-SILICATE NANOCOMPOSITES Ren J; Silva A S; Krishnamoorti R Houston,University A series of intercalated nanocomposites consisting of polystyrene-block-polyisoprene diblock copolymers and dimethyldioctadecylammonium-modified montmorillonite was prepared, and the linear viscoelastic properties determined in the melt state. The linear dynamic oscillatory moduli and the stress relaxation moduli were in quantitative agreement, suggesting that the short time relaxation of the nanocomposites was unaffected by the presence of the silicate. At long times, or at the equivalent low frequency, significantly different viscoelastic behaviour was observed. The composites containing in excess of 6.7 wt% montmorillonite exhibited pseudosolid-like behaviour. The long time behaviour was attributed to the presence of anisotropic stacks of silicate sheets randomly oriented, which formed a percolated network structure which was incapable of complete relaxation. It is proposed that this observation was supported by the ability of large-amplitude

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oscillatory shear to orient the nanocomposites and to increase their liquid-like character. 35 refs. USA

Accession no.778307 Item 318 Journal of Applied Polymer Science 76, No.12, 20th June 2000, p.1825-30 INTERCALATIVE REDOX POLYMERIZATION AND CHARACTERIZATION OF POLY(NVINYL-2-PYRROLIDINONE) IN THE GALLERY OF VERMICULITE: A NOVEL INORGANICORGANIC HYBRID MATERIAL Nisha A; Rajeswari M K; Dhamodharan R Indian Institute of Technology A poly(N-vinyl-2-pyrrolidinone)-vermiculite hybrid material was synthesised and characterised by various spectroscopic techniques, X-ray diffraction(XRD) and thermal analysis. The polymer was synthesised by intercalative redox polymerisation of the monomer at 110C, using copper(II)-ion-exchanged vermiculite. XRD analysis following intercalative polymerisation indicated the presence of two prominent peaks with corresponding d(002) spacing of 14.3 A (intercalated) and 9.9 A (not intercalated), suggesting the formation of a partially intercalated hybrid material. ESR studies of the intercalated material showed values of ‘g’ different from that of the Cu(II)-ion-exchanged vermiculite, indicating that polymer formed in the gallery of vermiculite complexes with the unreacted Cu(II). TGA indicated the amount of polymer in the gallery spacing to be about 20 mass %, which was confirmed by iodine labelling of the PNVP in the nanocomposite, followed by UV spectroscopy. The IR absorption peaks corresponding to PNVP, together with the XRD and thermal analysis data, confirmed that the gallery expansion was due to the formation of a partially intercalated inorganic-organic hybrid material. 34 refs. INDIA

Accession no.776391 Item 319 Macromolecular Materials and Engineering Vol.275, Feb.2000, p.8-17 POLY(PROPYLENE)/ORGANOCLAY NANOCOMPOSITE FORMATION: INFLUENCE OF COMPATIBILIZER FUNCTIONALITY AND ORGANOCLAY MODIFICATION Reichert P; Nitz H; Klinke S; Brandsch R; Thomann R; Muelhaupt R Freiburger Materialforschungszentrum; Freiburg,Institut fur Makromolekulare Chemie PP composites containing synthetic sodium fluoromica, modified to render it organophilic by cation exchange with different aliphatic amines, were obtained by melt extrusion at 210C in order to study the influence of silicate

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modification and the addition of compatibiliser. Only dodecyl, hexadecyl and octadecyl-modified silicates, together with maleic anhydride-grafted PP as the compatibiliser, promoted exfoliation and self-assembly of individual silicate layers within the PP matrix, as shown by TEM micrographs. 26 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.774360 Item 320 Polymer Plastics Technology and Engineering 39, No.2, 2000, p.293-303 EFFECTS OF SHEAR AND THERMAL HISTORY ON THE MICROSTRUCTURE OF SOLUTION POLYMERIZED POLY(METHYL METHACRYLATE)-CLAY COMPOSITES Tabtiang A; Lumlong S; Venables R A Mahidol University PMMA-clay composites were synthesised by free-radical solution polymerisation of MMA in the presence of clay that was pre-intercalated with dodecylammonium or hexadecyltrimethylammonium ions. Neither the diffraction peak from the (001) plane nor the 00l reflections for the (001) plane were observed during Xray characterisation, showing that the clay particles were greatly expanded (i.e. exfoliated) in the reaction products, due to the presence of large amounts of polymer between the clay layers. Syntheses carried out with high clay loadings resulted in reductions in the weight- and numberaverage molec.wts. and increases in the polydispersities of the polymers, caused by chain transfer to active sites on the surface of the clay. It was found that heat and shear, during subsequent processing of the reaction products, resulted in reordering of the microstructure through narrowing of the clay galleries with the partial exclusion of the polymer. The final interlayer spacings were determined by the orientation and lengths of the preintercalated alkylammonium ions. It was concluded that the exfoliated structure created during polymerisation was unstable under the processing conditions and, consequently, reordered into a more stable form. 14 refs. THAILAND

Accession no.771918 Item 321 Macromolecules 33, No.6, 21st March 2000, p.2000-4 SYNTHESIS OF POLYCARBONATE-LAYERED SILICATE NANOCOMPOSITES VIA CYCLIC OLIGOMERS Xinyu Huang; Lewis S; Brittain W J; Vaia R A Akron,University; US,Air Force Research Laboratory A partially exfoliated bisphenol A polycarbonate nanocomposite was prepared by using carbonate cyclic oligomers and ditallow dimethyl exchanged

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montmorillonite(B34). Wide-angle X-ray diffraction indicated that exfoliation of this organically modified layered silicate occurred after mixing with the cyclic oligomers in a Brabender mixer for 1 h at 180C. Subsequent ring-opening polymerisation of the cyclic oligomers converted the matrix into linear polymer without disruption of the layer dispersion. TEM revealed that a partially exfoliated structure was obtained, although no indication of layer correlation was observed in wideangle X-ray diffraction. If linear polycarbonate was similarly treated with B34 in a Brabender mixer, only an intercalated hybrid was obtained. Furthermore, conventional melt or solution processing of the B34 with either linear polycarbonate or cyclic oligomers yielded intercalated nanocomposites with interlayer spacings of 3.27 and 3.6-3.8 nm, respectively. These results demonstrated that consideration of molecular architecture (cyclic versus linear) and kinetics (medium viscosity and shear) was critical for nanocomposite formation. 37 refs. USA

Accession no.771877 Item 322 Journal of Applied Polymer Science 75, No.6, 7th Feb.2000, p.796-801 SYNTHESIS, CHARACTERIZATION AND PROPERTIES OF CLAY-POLYACRYLATE HYBRID MATERIALS Chen Z; Huang C; Liu S; Zhang Y; Gong K South China,University of Technology; Zaozhuang Normal College Using an intercalation-polymerisation process, a novel hybrid material derived from clay and poly(butyl acrylate) was prepared. Using a number of analysis techniques the structure of the composite was investigated. The hybrid material was shown to have a decomposition central temperature of 485.6C which is 83C higher than that of poly(butyl acrylate). 25 refs. CHINA

Accession no.769021 Item 323 Polymer 41, No.10, 2000, p.3887-90 SYNTHESIS AND STRUCTURE OF SMECTIC CLAY/POLY(METHYL METHACRYLATE) AND CLAY/POLYSTYRENE NANOCOMPOSITES VIA IN SITU INTERCALATIVE POLYMERIZATION Okamoto M; Morita S; Taguchi H; Kim Y H; Kotaka T; Tateyama H Toyota Technological Institute; Kyushu,National Industrial Research Institute Clay/poly(methyl methacrylate) and clay/polystyrene nanocomposites were prepared using in-situ free radical polymerisation with lipophilised smectic clays. The intercalation spacing in the nanocomposites and the

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References and Abstracts

degree of dispersion were investigated using X-ray diffraction and transmission electron microscopy, respectively. Flocculation was observed under some conditions, attributed to hydroxylated edge-edge interaction of silicate layers. The nanocomposites had higher storage moduli and glass transition temperatures compared with the pure polymers. 7 refs. JAPAN

Accession no.767832 Item 324 Whitby, Ont., c.2000, pp.2. 27 cms. 6/4/00 DARTEK T-424 NA FOR HIGH PERFORMANCE INDUSTRIAL USES. TECHNICAL DATA DuPont Canada Inc. Dartek T-424NA is a clear thin uniaxially oriented film made from nylon 6,6, and designed for use as a release and carrier sheet. It has high shrinkage for greater wrap tension during high temperature curing processes by matching the shrinkage characteristics of working compounds. Dimensions, properties and typical applications are indicated. CANADA

Accession no.767382 Item 325 Polymer Bulletin 43, Nos.4-5, Nov./Dec. 1999, p.395-402 THERMAL PROPERTIES AND FLAMMABILITY OF ACRYLIC NANOCOMPOSITES BASED UPON ORGANOPHILIC LAYERED SILICATES Dietsche F; Mulhaupt R Albert-Ludwigs,University Thermal and mechanical properties of methyl methacrylate-dodecyl methacrylate copolymer nanocomposites based on exfoliated organophilic layered silicates were investigated as a function of the silicate and comonomer content. Flammability studies are discussed. Morphological properties were examined using TEM. 16 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.763801 Item 326 Polymer 41, No.4, 2000, p.1345-53 SYNTHESIS AND CHARACTERIZATION OF NOVEL SEGMENTED POLYURETHANE/CLAY NANOCOMPOSITES Chen T-K; Tien Y-I; Wei K-H Taiwan,National Chiao-Tung University Organoclays were formed by treatment of sodium montmorillonite clay with 12 aminolauric acid or benzidine (BZD). The exfoliation of the silicate layers in

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polyurethane (PU), forming nanocomposites, was studied using X-ray diffraction and transmission electron microscopy. Measurement of glass transition temperature and degree of phase separation by differential scanning calorimetry and Fourier transform infrared spectroscopy showed that the segmented structure of the PU was not affected by the presence of the silicate layers. The composite containing 1% of the BZD-treated clay had a two-fold increase in tensile strength and a three-fold increase in elongation compared with the pure PU. Both clays gave composites with lower water absorptions than that of the pure PU. 27 refs. TAIWAN

Accession no.760695 Item 327 Journal of Applied Polymer Science 74, No.14, 27th Dec.1999, p.3359-64 PREPARATION AND MECHANICAL PROPERTIES OF POLYSTYRENE-CLAY HYBRIDS Hasegawa N; Okamoto H; Kawasumi M; Usuki A Toyota Central R & D Laboratories Inc. PS-clay hybrids were prepared by melt blending a styrenevinyloxazoline copolymer with organophilic clay. In the hybrids, the silicate layers of the clay were delaminated and dispersed homogeneously to the nanometer level. The moduli of the hybrids were higher that that of the PS copolymer. The tensile modulus of the hybrid with 5 wt % clay, for example, was 1.4 times higher that that of the PS copolymer. 19 refs. JAPAN

Accession no.759985 Item 328 Journal of Materials Science Letters 18, No.19, 1st Oct.1999, p.1539-41 ORGANIC-INORGANIC HYBRID LIGHTEMITTING COMPOSITES: POLY(PPHENYLENE VINYLENE) INTERCALATED CLAY NANOPARTICLES Winkler B; Dai L; Mau A W-H CSIRO Poly(p-phenylene vinylene) (PPV) and its derivatives have been intensively studied since the first report on polymeric light emitting diodes (LEDs) in 1990. Owing to their relatively high photo/electroluminescence (PL/ EL) quantum efficiencies and good colour tunability through molecular engineering, PPV and its derivatives are among the most attractive materials for EL applications. PPV derivatives substituted with oligo(ethylene oxide) side chains (EO-PPVs) have been prepared for use in both LEDs and light emitting electrochemical cells (LECs). It was found that the covalent linkages between the EO and PPV constituents can effectively minimise the phase separation problem

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often associated with conventional LEC devices based on mixtures of conjugate light-emitting polymers and polymeric ion conductors. Organic-inorganic hybrid composites constitute a new class of materials, which could show properties characteristic of both constituent components with potential synergetic effects. In this context, certain electroluminescent organic-inorganic hybrid materials are prepared by sol-gel chemistry while various polymers have been incorporated into clay particles through either a solution or a melt intercalation process. Here, the first solution intercalation of EO3-PPV into clay nanoparticles for light-emitting applications is reported. 30 refs. AUSTRALIA

Accession no.757035 Item 329 Macromolecules 32, No.20, 5th Oct.1999, p.6792-9 REINFORCEMENT OF POLY(DIMETHYLSILOXANE) ELASTOMERS BY CHAIN-END ANCHORING TO CLAY PARTICLES Takeuchi H; Cohen C Cornell University The effects of network imperfections and precursor chain ends on the reinforcement of PDMS networks with clay were investigated. The end-linked PDMS networks having a broad range of crosslinker-toprecursor ratios were produced from difunctional hydroxyl-terminated and vinyl-terminated PDMS precursors, which had similar MWDs, and were crosslinked with tetrafunctional compounds, such as tetraethyl orthosilicate. The composite PDMS elastomers contained low concentrations of montmorillonite nanosize clay particles. The results indicated that reinforcement could be attributed to the anchoring of the hydroxyl end group to the filler, reducing the soluble fraction and binding pendent chain ends. 22 refs. USA

Accession no.756393 Item 330 Journal of Materials Science Letters 18, No.21, 1st Nov.1999, p.1761-3 PREPARATION AND PROPERTIES OF PMMA/ CLAY NANOCOMPOSITE Guohua Chen; Xiuqin Chen; Zhiyong Lin; Wei Ye; Kangde Yao Huaqiao,University; Tianjin,University A procedure was developed for the preparation of organoclay/PMMA hybrid in which 1 nm thick silicate layers of montmorillonite were dispersed in the PMMA matrix individually and homogeneously. The nanocomposites were characterised by X-ray diffraction,

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TEM and SEM. The barrier properties of the composites towards trichloromethane were examined. 11 refs. CHINA

Accession no.755865 Item 331 Chemistry of Materials 11, No.9, Sept.1999, p.2372-81 CLAY-POLYVINYLPYRIDINE NANOCOMPOSITES Fournaris K G; Karakassides M A; Petridis D; Yiannakopoulou K Athens,Democritos National Research Centre Nanocomposites of montmorillonite with poly-4vinylpyridinium salts (1,2-form), the quaternised ionene polymer (1,6-form) and poly-4-vinylpyridine (neutral form) were synthesised and characterised. Only one macromolecular sheet of poly-4-vinylpyridinium polyelectrolyte or the quaternised polyelectrolyte entered the interlayer space, regardless of the amount of polyelectrolyte used in the intercalation. Adsorption isotherms for the different forms of poly-4-vinylpyridine revealed that surface saturation coverage increased in the order partially protonated poly-4-vinylpyridine, quaternised ionene form, completely protonated poly-4vinylpyridine. Models were proposed to explain the different uptake of the three derivatives and the surface selectivity towards quaternised polycations. The electrochemical results confirmed that intercalative polymerisation produced only the quaternised form of the polymer and revealed that protonation of poly-4vinylpyridine occurred because of the acidity of the clay layers. 26 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GREECE; WESTERN EUROPE

Accession no.754098 Item 332 Macromolecules 32, No.20, 5th Oct.1999, p.6718-24 CONFORMATION OF POLY(ETHYLENE OXIDE) INTERCALATED IN CLAY AND MOS2 STUDIED BY TWO-DIMENSIONAL DOUBLEQUANTUM NMR Harris D J; Bonagamba T J; Schmidt-Rohr K Massachusetts,University; Sao Paulo,University The molecular conformation of the OC-CO bonds of PEO intercalated in hectorite and MoS2 was investigated using double-quantum solid-state NMR spectroscopy. Conformational statistics of the OC-CO bonds were determined using PEO with 13% carbon 13-carbon 13 labelled units. It was found that these bonds in narrow interlayer gaps of 0.8, 0.85 and 1.0 nm thickness exhibited a gauche content of about 90%. 43 refs. BRAZIL; USA

Accession no.753656

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References and Abstracts

Item 333 Macromolecular Rapid Communications 20, No.8, Aug.1999, p.450-2 SYNTHESIS AND ELECTRORHEOLOGICAL PROPERTIES OF POLYANILINE-NA+MONTMORILLONITE SUSPENSIONS Kim J W; Kim S G; Choi H J; Jhon M S Inha,University; Carnegie-Mellon University Polyaniline-Na+-montmorillonite nanocomposite particles were synthesised using an emulsion intercalation method and electrorheological(ER) fluids were prepared by dispersing the synthesised nanocomposite particles in an electrically insulating silicone oil. The conducting polymer (polyaniline) was inserted into the layers of clay and this insertion of polyaniline was confirmed by X-ray diffraction. ER properties were determined using a rotational rheometer equipped with a high voltage generator. 16 refs. KOREA; USA

Accession no.748428 Item 334 Macromolecular Rapid Communications 20, No.8, Aug.1999, p.423-30 POLYOLEFIN NANOCOMPOSITES FORMED BY MELT COMPOUNDING AND TRANSITION METAL CATALYZED ETHENE HOMO- AND COPOLYMERIZATION IN THE PRESENCE OF LAYERED SILICATES Heinemann J; Reichert P; Thomann R; Muelhaupt R Freiburger Materialforschungszentrum; AlbertLudwigs,University Nanocomposites of HDPE, LLDPE and highly branched PE rubbers were prepared both by means of melt compounding and by ethene homo- and copolymerisation in the presence of layered silicates which were rendered organophilic via ion exchange with various quaternary alkyl ammonium cations. In comparison with melt compounding, in-situ ethene homo- and copolymerisation, catalysed by methylaluminoxaneactivated zirconocene, nickel and palladium catalysts, proved more effective in nanocomposite formation, as evidenced by larger interlayer spacings and formation of exfoliated anisotropic nanosilicates with high aspect ratio. 22 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.748423 Item 335 Chemistry of Materials 11, No.7, July 1999, p.1942-7 THERMALLY AND MECHANICALLY ENHANCED CLAY/POLYIMIDE NANOCOMPOSITE VIA REACTIVE ORGANOCLAY

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Tyan H-L; Liu Y-C; Wei K-H National Chiao Tung University The preparation of high modulus and heat stable clay/ polyimide nanocomposites from reactive organoclay and polyamic acid is described and the thermal, dynamic and mechanical properties of these nanocomposites are reported. The clay was formed by using pphenylenediamine as a swelling agent for silicate layers of montmorillonite. Both X-ray and transmission electron microscopy confirmed that the swelling process, which was irreversible, gave a nanostructured material containing intercalated nanometer silicate layers dispersed in pyromellitic dianhydride-4,4'-oxydianiline. 24 refs. TAIWAN

Accession no.747466 Item 336 Journal of Applied Polymer Science 73, No.14, 29th Sept.1999, p.2971-6 PREPARATION AND EVALUATION OF COMPOSITES FROM MONTMORILLONITE AND SOME HETEROCYCLIC POLYMERS. II. A NANOCOMPOSITE FROM NVINYLCARBAZOLE AND FERRIC CHLORIDEIMPREGNATED MONTMORILLONITE POLYMERIZATION SYSTEM Ray S S; Biswas M Calcutta,Presidency College Polymerisation of N-vinylcarbazole in the presence of ferric chloride-impregnated montmorillonite was shown to result in the formation of a poly(N-vinylcarbazole)montmorillonite composite. X-ray diffraction analysis of the composite revealed no expansion for d001 spacing, in sharp contrast to that for the same composite prepared in the absence of ferric chloride. This indicated that the polymer was not intercalated in the montmorillonite lamellae but adhered to it in the same was as polypyrrole in colloidal silica, zirconia or tin oxide nanocomposite systems. TEM analysis revealed the particle size of the composite to be in the range 30-40 nm. The DC conductivity of the polymer-montmorillonite composite was in the range 0.00003 to 0.00005 S/cm depending on the ferric chloride loading of montmorillonite. 24 refs. INDIA

Accession no.747404 Item 337 Journal of Applied Polymer Science 73, No.11, 12th Sept.1999, p.2063-8 PREPARATION AND PROPERTIES OF ORGANOSOLUBLE MONTMORILLONITE/ POLYIMIDE HYBRID MATERIALS Zi-Kang Zhu; Yong Yang; Jie Yin; Xin-Yu Wang; YangChuan Ke; Zong-Neng Qi Shanghai,Jiao Tong University; Beijing,Institute of Chemistry

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The above materials were prepared using a monomer solution intercalation polymerisation method. Montmorillonite was organo-treated with p-aminobenzoic acid and the organosoluble polyimide was based on pyromellitic dianhydride and 4,4'-diamino-3,3'dimethyldiphenylmethane. The particle size of the montmorillonite in the hybrid containing 1 wt % of montmorillonite was about 400 nm. The strength and the toughness of montmorillonite/polyimide hybrids were improved simultaneously when the montmorillonite content was below 5 wt %. The thermal stabilities of montmorillonite/polyimide hybrids were markedly improved and their thermal expansion coefficients were reduced. When the montmorillonite content was below 5 wt %, the montmorillonite/polyimide hybrids were soluble in strong aprotic polar organic solvents. 16 refs. CHINA

Accession no.744929

Item 340 Polymer Bulletin 42, No.5, May 1999, p.619-26 SYNTHESIS AND CHARACTERIZATION OF PSCLAY NANOCOMPOSITE BY EMULSION POLYMERIZATION Myoung Whan Noh; Dong Choo Lee Inha,University Nanocomposites of PS and Na(superscript +)montmorillonite were prepared by emulsion polymerisation. X-Ray diffraction and IR spectroscopy showed that the PS was inserted between the lamellar clay layers. The enhanced thermal and mechanical properties of the composites were attributed to the fixing of the polymer chains between the clay layers and the restricted segmental motions near the organic-inorganic surfaces,together with the fine dispersion of clay particles into the polymer matrix. 14 refs. SOUTH KOREA

Item 338 Antec ’99. Volume II. Conference proceedings. New York City, 2nd-6th May 1999, p.1628-32. 012 POLYMERIC/CLAY NANOCOMPOSITES FOR BIODEGRADABLE APPLICATIONS Ratto J A; Steeves D M; Welsh E A; Powell B E US,Army; Southern Clay (SPE) Details are given of the preparation of a series of biodegradable polycaprolactone/clay nanocomposites by in situ polymerisation and twin screw extrusion. Characterisation was undertaken with regard to processability, biodegradation, morphology, thermal properties and mechanical properties. 12 refs. USA

Accession no.744510 Item 339 Journal of Materials Science Letters 18, No.9, 1st May 1999, p.711-3 MODIFICATION OF POLYETHYLENE OXIDE WITH POLYMETHYL METHACRYLATE IN POLYMER-LAYERED SILICATE NANOCOMPOSITES Chen W; Xu Q; Yuan R Z Wuhan,University of Technology The direct melt intercalation of PEO with PMMA in lithiumexchange layered silicate was studied. The polymer-layered silicate hybrids were analysed by X-ray diffraction and DSC and the influence of modification of the PEO with PMMA on polymer state and ionic transport was investigated by magic angle spinning NMR spectroscopy. It was found that PMMA modified the PEO chains and increased their random arrangement, weakening the interaction between lithium ions and polymer chains in layers. 6 refs. CHINA

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Accession no.741943 Item 341 Journal of Applied Polymer Science 73, No.3, 18th July 1999, p.425-30 MONTMORILLONITE CLAY/POLY(METHYL METHACRYLATE) HYBRID RESIN AND ITS BARRIER PROPERTY TO THE PLASTICIZER WITHIN POLY(VINYL CHLORIDE) COMPOSITE Guohua Chen; Kangde Yao; Jingtai Zhao Tianjin,University; Huaqiao,University; Xiamen,University A PMMA-clay hybrid resin was prepared via bulk polymerisation of MMA monomer in the presence of montmorillonite intercalated with an ammonium salt of octadecylamine. The products were characterised by IR spectroscopy, X-ray diffraction, pyrolysis gas chromatography and TEM. Results confirmed that the resin was intercalated with PMMA molecules. The layer spacing of montmorillonite was enlarged, whereas the silicate layers were homogeneously dispersed individually. When the PMMA-clay hybrid was blended with plasticised PVC, the resulting composite exhibited good barrier properties in preventing the migration of plasticiser from the inner matrix to the surface of the product. This was presumably caused by the barrier property of the silicate layers dispersed in the composite. 11 refs. CHINA

Accession no.738082 Item 342 Polymer 40, No.17, 1999, p.4877-86 ENHANCEMENT OF IMIDIZATION OF POLY(AMIC ACID) THROUGH FORMING

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References and Abstracts

POLY(AMIC ACID)/ORGANOCLAY NANOCOMPOSITES Horng-Long Tyan; Yau-Cheng Liu; Kung-Hwa-Wei Taiwan,National Chiao Tung University The imidisation kinetics of poly(amic acid)/ organoclay nanocomposites were studied using in-situ FTIR spectroscopy at several temperatures. The poly(amic acid) used consisted of pyromellitic dianhydride and 4,4'-oxydianiline, and the organoclay was produced by the modification of montmorillonite with p-phenylene diamine. When a small amount of the organoclay was dispersed in the poly(amic acid), the imidisation temperature and imidisation time of the poly(amic acid) could be greatly reduced. When two parts of exfoliated silicate layers of organoclay were dispersed in poly(amic acid), the imidisation temperature could be lowered by 50C, to 250C, for complete imidisation to occur. Also, when the amount of organoclay was increased to seven parts, the imidisation time of the poly(amic acid) at 250C could be reduced to 15 min. Using a first-order reaction to model the imidisation kinetics of the poly(amic acid)/ organoclay, a 20% drop in the activation energy for imidisation of the composite containing 7 phr organoclay was observed compared with that for the imidisation of the neat poly(amic acid). The thermal degradation temperature of the composite containing 7 phr organoclay was about 25C higher than that of the neat poly(amic acid). 21 refs. TAIWAN

Accession no.737373 Item 343 Journal of Applied Polymer Science 72, No.13, 24th June 1999, p.1895-903 BONDING BETWEEN EPOXIDIZED NATURAL RUBBER AND CLAY IN PRESENCE OF SILANE COUPLING AGENT Manna A K; Tripathy D K; De P P; De S K; Chatterjee M K; Peiffer D G Indian Institute of Technology; ICI India Ltd.; Exxon Research & Engineering Co. Using bound rubber determination, Monsanto rheometric studies, solvent swelling, measurement of physical properties and IR spectroscopic studies, it was shown that epoxidised NR and hard clay interacted chemically to form Si-O-C bond during high-temp. (180C) moulding. It was also observed that addition of the silane coupling agent N-3-(N-vinyl benzyl amino)-ethyl-gammaaminopropyl trimethoxysilane monohydrogen chloride enhanced the extent of the chemical interaction with the formation of coupling bonds of Si-O-Si type between clay and the coupling agent and C-N bonds between epoxidised NR and the coupling agent. 18 refs. INDIA

Accession no.736630

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Item 344 Journal of Materials Science 34, No.7, 1st April 1999, p.1543-52 RHEOLOGICAL PROPERTIES OF POLY(ACRYLAMIDE)-BENTONITE COMPOSITE HYDROGELS Deyu Gao; Heimann R B; Williams M C; Wardhaugh L T; Muhammad M Heilongjiang,Academy of Sciences; Freiburg,University of Mining & Technology; Alberta,University; NOVA Chemicals Ltd.; Robinson D.B.,Research Ltd. Dynamic and transient rheological properties were measured for a series of hydrogel composites whose microstructure was reported previously. The hydrogels, which were composed of radiation-crosslinked polyacrylamide and bentonite clay particles acting as polymer-absorbing mechanical crosslink sites, were prepared in the range 50-95% water. Dynamic storage and loss moduli were obtained at several strain amplitudes, over a range of frequency from 0.01 to 100 rad/s. Step strains produced stress peaks and decays interpreted in terms of the stress relaxation modulus, carried out to 10,000 s. Rheological complications with possible slip, yielding and non-linearities were avoided but are discussed in detail. Rubberlike rheology was exhibited in general and the dynamic storage modulus was found to depend exponentially on solids content, with parameters only weakly dependent on frequency. A practical measure of gel strength, defined in terms of the size of a water-containing cube that was mechanically stable, was used to demonstrate that these gels had considerable strength, with even a 1m cube stable at 80% water. 15 refs. CANADA; CHINA; EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.733321 Item 345 Macromolecular Chemistry & Physics 200, No.5, May 1999, p.955-63 NEW CATALYTIC SYSTEMS BASED ON INTERCALATED POLYMERMONTMORILLONITE SUPPORTS Akelah A; El-Borai M A; Abd El-Aal M F; Rehab A; Abou-Zeid M S Tanta,University A composite material was prepared by ion exchange between the ammonium salt of the alpha,omega-diamineterminated oligo(butadiene-co-acrylonitrile) and the interlamellar cation of the montmorillonite. Grafted freeradical polymerisation of both oligo(oxyethylene) methacrylate and chloromethylstyrene supported on the above composite was conducted. The chloromethyl groups were modified to produce onium salts which were suitable as phase transfer catalysts. The catalytic activities were investigated in nucleophilic reactions of thiocyanate,

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cyanate and nitrite with alkyl or aryl halides. The effects of the nature and structure of the support, amount of catalyst, solvent and temp. on the rate of reactions were studied. 16 refs. EGYPT

Accession no.733196 Item 346 Polymer 40, No.15, 1999, p.4407-14 PREPARATION AND PROPERTIES OF HYBRIDS OF ORGANO-SOLUBLE POLYIMIDE AND MONTMORILLONITE WITH VARIOUS CHEMICAL SURFACE MODIFICATION METHODS Yong Yang; Zi-kang Zhu; Jie Yin; Xin-yu Wang; Zongeng Qi Shanghai,Jiao Tong University; Chinese Academy of Sciences Hybrids of montmorillonite(MMT) and organo-soluble polyimide were prepared using a monomer solution intercalation polymerisation method. The organo-soluble polyimide was based on pyromellitic dianhydride and 4,4'diamino-3,3'-dimethyldiphenylmethane. The MMT was organo-modified with three types of intercalation agents, i.e. amino acids, primary aliphatic amines and quaternary ammonium salt. The dispersion behaviour of MMT in organic solvents and polyimide depended on the type of functional group and the bulky group of the intercalation agent. The MMT modified with 1-hexadecylamine was observed to possess the best dispersion behaviour. The properties of a MMT/polyimide hybrid were also significantly dependent on the dispersion behaviour of MMT particles. When the MMT was well dispersed, a MMT/polyimide hybrid would possess desired properties such as strengthening and toughening at the same time, improved thermal stability, decreased thermal expansion coefficient, retention of the solubility of the polyimide matrix and high optical transparency. 18 refs.

with the natural mineral were applied to act as compatibiliser. The interaction between the first part of the compatibiliser was preferentially an ionic interaction or an interaction between hydrogen bonds. This interaction led to a separation of the mineral into single sheets and/or small clusters containing 2-10 sheets and a subsequent homogenous incorporation of these clusters into a polymer matrix material. 15 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; NETHERLANDS; WESTERN EUROPE

Accession no.731801 Item 348 Journal of Polymer Science : Polymer Physics Edition 37, No.8, 15th April 1999, p.847-57 OXYGEN BARRIER PROPERTIES OF CRYSTALLIZED AND TALC-FILLED POLY(ETHYLENE TEREPHTHALATE) Sekelik D J; Stepanov E V; Nazarenko S; Schiraldi D; Hiltner A; Baer E Case Western Reserve University; Hoechst Corp. The improvement of the oxygen barrier properties of PETP on incorporation of an impermeable phase such as a crystalline phase or talc platelets was examined. Crystallinity was induced by crystallisation from the glassy state (cold crystallisation). Microlayering was used to create talc-filled structures with controlled layer structure. The reduction of permeability in crystallised and talc-filled PETP was well described by Nielsen’s model. Changes in permeability of crystalline PETP could not be ascribed to the filler effect of crystallites alone. Data on solubility, obtained from measurements of oxygen transport coefficients, confirmed a previous finding that the amorphous phase density of PETP decreased upon crystallisation. The data were amenable to interpretation by free volume theory. Talc-filled materials processed by different methods showed the same permeability. Much better mechanical properties were, however, achieved by microlayering. 34 refs.

CHINA

USA

Accession no.732029

Accession no.727122

Item 347 Acta Polymerica 50, No.4, April 1999, p.122-6 NANOCOMPOSITES FROM POLYMERS AND LAYERED MINERALS Fischer H R; Gielgens L H; Koster T P M TNO-TPD

Item 349 Journal of Materials Science 34, No.3, 1st Feb.1999, p.497-508 COMPOSITION-DEPENDENT PROPERTIES OF PE/KAOLIN COMPOSITES. II. THERMOELASTIC BEHAVIOUR OF BLOWMOULDED SAMPLES Privalko V P; Balta Calleja F J; Sukhorukov D I; Privalko E G; Walter R; Friedrich K CSIC; Ukraine,National Academy of Sciences; Kaiserslautern,University

Composites consisting of polymer matrix materials and natural or synthetic layered minerals, e.g. clays, were prepared by using special compatibilising agents between these two intrinsically non-miscible components. Block or graft copolymers combining one part of the polymer that was identically and/or completely miscible with the organic polymer and another part that was compatible

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Blow moulded HDPE filled with kaolin were characterised by wide-angle X-ray scattering, microhardness and stretching calorimetry. The thermoelastic behaviour of all

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References and Abstracts

samples below the apparent yield point was quantitatively described by classic equations for elastic solids. Thermoelastic parameters of the boundary interphase are discussed interms of predictions of the step-by-step averaging approach. 21 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; SPAIN; UKRAINE; WESTERN EUROPE

Accession no.726772 Item 350 Journal of Applied Polymer Science 71, No. 7, 14th Feb. 1999, p.1139-46 CRYSTALLISATION, PROPERTIES, AND CRYSTAL AND NANOSCALE MORPHOLOGY OF POLYETHYLENE TEREPHTHALATE-CLAY NANOCOMPOSITES Yangchuan Ke; Chenfen Long; Zongneng Qi Beijing,Institute of Chemistry The crystallisation process and crystal morphology of PETP-clay nanoscale composites prepared by intercalation, followed by in-situ polymerisation, were investigated by SEM, TEM, DSC and X-ray techniques, together with mechanical methods. Results of the nonisothermal crystallisation dynamics show that the nanocomposites of PETP have three times greater crystallisation rate than that of pure PETP. The thermal properties of nanocomposites of PETP showed heat distortion temperatures 20-50C higher than the pure PETP, while with a clay content of 5%, the moduli of nanocomposites of PETP were as much as 3 times that of pure PETP. Statistical results of particle distribution show that the average nanoscale size ranges from 10 to 100 nm. The particles are homogeneously distributed with their size percentages in normal distribution. The agglomeration of particles is 4% or so with some particle sizes in the micrometer scale. The morphology of exfoliated clay particles is in a disordered state, in which the morphology of the PETP spherulites are not easy to detect in most microdomains compared with pure PETP. The molecular chains intercalated in the interlamellae of clay are confined to some extent, which explains the narrow MWD of nanocomposites of PETP . The stripebelt morphology of the intercalated clays show that polymer PETP chains are intercalated into the enlarged interlamellar space. The starting materials for nanocomposites of PETP are termed treated clay and PETP monomers. Data includes melting point, Tg, heat distortion temperature, heat of fusion, decomposition temperature and tensile modulus. 18 refs. CHINA

Accession no.718463 Item 351 Journal of Applied Polymer Science 71, No. 7, 14th Feb. 1999, p.1133-8 STUDIES ON NYLON 6/CLAY NANOCOMPOSITES BY MELT-

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INTERCALATION PROCESS Liu L; Qi Z; Zhu X Beijing,Institute of Chemistry Organically modifed montmorrillonite (organoclay) was prepared by a cation exchange reaction between sodium montmorrillonite and ocatadecylammonium salt. Nanocomposites were prepared by mechanically mixing organoclay and polyamide-6 in a twin screw extruder. Extrudate was pelletised and injection moulded into test pieces. X-ray diffraction and DSC results show that the crystal structure and crystallisation behaviours of the nanocomposites are different from those of polyamide-6. Mechanical and thermal testing shows that the properties of the nanocomposites are superior to nylon 6 in terms of the heat distortion temperature, strength, and modulus without sacrificing their impact strength. This is due to the nanoscale effects and the strong interaction between the nylon 6 matrix and the clay interface, as revealed by X-ray diffraction, TEM and Molau testing. The Molau tests show the strong interaction between the nylon 6 matrix and the organoclay nanoparticles. 8 refs. CHINA

Accession no.718462 Item 352 Chemistry of Materials 11, No.1, Jan.1999, p.16-9 INTERCALATION OF POLYMERS IN CALCIUM SILICATE HYDRATE: A NEW SYNTHETIC APPROACH TO BIOCOMPOSITES? Matsuyama H; Young J F Illinois,University Polymer molecules intercalated between the layers of calcium silicate hydrate during its precipitation from aqueous solution were shown to expand the interlayer dimension. Alteration in the structure by changes in bulk composition allowed polymers of different charge to be intercalated. The polymer chains could adopt an extended linear conformation between the layers. In the example shown, PVAl chains lay along the a axis perpendicular to the plane of the page, between the silicate chains of the layer. 14 refs. USA

Accession no.715473 Item 353 Chemistry of Materials 11, No.1, Jan.1999, p.3-6 DIRECT INTERCALATION OF POLYVINYLPYRROLIDONE(PVP) INTO KAOLINITE BY A REFINED GUEST DISPLACEMENT METHOD Komori Y; Sugahara Y; Kuroda K Waseda,University Direct intercalation of PVP into the interlayer space of kaolinite at room temp. was achieved by a refined guest

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displacement method by using both a kaolinite-methanol intercalation compound and PVP dissolved in methanol. The product could be easily separated from the polymer solution by centrifugation. This procedure was superior to the in situ polymerisation of monomers between the layers from the viewpoint of the possibility of controlling the degree of polymerisation by choosing polymers with appropriate molec.wt. 32 refs. JAPAN

Accession no.715472 Item 354 Polymer Gels & Networks 6, Nos.3-4, 1998, p.205-15 SWELLING AND COLLAPSE OF THE GEL COMPOSITES BASED ON NEUTRAL AND SLIGHTLY CHARGED POLYACRYLAMIDE GELS CONTAINING NA-MONTMORILLONITE Churokchkina N A; Starodoubtsev S G; Khokhlov A R Russian Academy of Sciences; Moscow,State University Clay-polymer hydrogel composites are prepared on the basis of neutral and slightly charged cationic and anionic polyacrylamide gels containing different amounts of the clay mineral Na-montmorillonite. The swelling and collapse in water acetone media and the mechanical behaviour of such gels are studied. It is shown that the clay incorporated into neutral polyacrylamide gel hardly influences its degree of swelling in water. On the other hand, for the anionic and especially for the cationic gels, the swelling in the presence of clay decreases. The elastic modulus of gels with incorporated clay is higher, while the amplitude of the acetone-induced collapse is lower than for the corresponding pure gel systems. 11 refs. RUSSIA

Accession no.714136 Item 355 ACS Polymeric Materials Science and Engineering. Fall Meeting 1998. Volume 79. Conference proceedings. Boston, Mas., 23rd-27th Aug.1998, p.178-9. 012 MICROMECHANICAL DEFORMATION PROCESSES IN PA12-LAYERED SILICATE NANOCOMPOSITE Kim G-M; Michler G H; Reichert P; Kressler J; Mulhaupt R Halle,Martin-Luther-Universitat; AlbertLudwigs,University As the use of polymers in structural applications increases, a new class of polymeric materials with a unique combination of high strength, modulus and toughness is being demanded. Hybrid organic-inorganic composites have been considered as a attractive representative. It has been found that by incorporating a very small amount of inorganic components (only a few wt.%) in the polymer

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matrix on a nanometer scale, unexpected mechanical properties can be synergistically achieved. Frequently used inorganic filler particles are platy clay mineral particles consisting of layered silicates in a range of 1100 nm in length and several nm in thickness (very large aspect ratio). Although a considerable development of synthetic approaches in polymer nanocomposites has been performed in the last few years, the appropriate mechanisms responsible for the improvement of mechanical properties in this subject are still not presented. The influence of the morphology of dispersed silicate layers in nylon 12 on the micromechanical deformation processes is investigated by high voltage electron microscopy using an in situ tensile technique. 3 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.712649 Item 356 Chemistry of Materials 10, No.12, Dec.1998, p.3769-71 NANOLAYER REINFORCEMENT OF ELASTOMERIC POLYURETHANE Zhen Wang; Pinnavaia T J Michigan,State University A thermoset PU-clay nanocomposite was prepared by curing a PU network in the presence of alkylammoniumexchanged forms of montmorillonite. Unusual stressstrain behaviour was observed for the elastomeric nanocomposites. The reinforcement effects of the silicate nanolayers not only significantly improved the tensile properties of the matrix but the strain-at-break also increased with increasing clay loading. Nanocomposite formation thus both strengthened and toughened the elastomeric matrix in comparison with the pristine polymer. 17 refs. USA

Accession no.710872 Item 357 Polymer Bulletin 41, No.5, Nov.1998, p.511-8 SYNTHESIS AND PROPERTIES OF POLYSTYRENE-ORGANOAMMONIUM MONTMORILLONITE HYBRID Jae Goo Doh; Iwhan Cho Korea,Advanced Institute of Science & Technology Styrene monomer was mixed with quaternary ammonium montmorillonites(org-MMTs) and polymerised in the presence of radical initiator. The resulting materials showed an expansion of interlayer distance. These hybrid materials exhibited higher thermal stability compared with the virgin PS or PS/pristine-MMT microcomposite. PS/ Bz-MMT, containing a benzyl unit similar to styrene in org-MMT, exhibited higher decomposition temp. even for

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References and Abstracts

KOREA

study the structure and dynamics of polymers in confined environments. Using both delaminated and intercalated hybrids, the statics and dynamics of polymers confined over distances ranging from the radius of gyration of the polymer to the statistical segment length of the chains can be studied. 12 refs.

Accession no.706463

USA

MMT loading as low as 0.3 wt % compared with other PS/org-MMT hybrids. It was found that the structural affinity between styrene monomer and the organic group of org-MMT played an important role in the structure and the properties of hybrid materials. 17 refs.

Item 358 Kobunshi Ronbunshu 55, No.8, 1998, p.477-82 Japanese STUDIES ON PRODUCTION OF NANOCOMPOSITES OF POLYAMIDE 6 WITH EXPANDABLE SYNTHETIC MICA. IV. DISPERSION OF INTERCALATION COMPOUNDS OF SYNTHETIC MICA WITH EPSILON-CAPROLACTAM INTO POLYAMIDE 6 Katahira S; Yasue K; Inagaki M Hokkaido,University; Unitika R & D Center Intercalation compounds of synthetic mica(MIC) with epsilon-caprolactam(epsilon-CL) were mixed in epsilonCL. This mixture was polymerised to polyamide-6, resulting in nanocomposites of polyamide-6 with highly dispersed mica. The mechanism of production of the nanocomposite was considered to proceed in three steps on the bases of the present and previous studies. In the first step, epsilon-CL was protonated by acid or under high pressure, and then MIC was formed by exchanging epsilon-CL+ ions with Na+ ions in the gallery of mica layers in the second step. At the third step, epsilon-CL was polymerised above 260C and polyamide-6 in the gallery of mica caused cleavage of mica into thin flakes. 5 refs. JAPAN

Accession no.699126 Item 359 Applied Organometallic Chemistry 12, Nos.10-11, Oct/Nov.1998, p.675-80 POLYMER-LAYERED SILICATE NANOCOMPOSITES: SYNTHESIS, PROPERTIES AND APPLICATIONS Giannelis E P Cornell University Polymer nanocomposites, especially polymer-layered silicate (PLS) nanocomposites, represent a radical alternative to conventionally (macroscopic) filled polymers. Because of their nanometer-size dispersion, the nanocomposites exhibit markedly improved properties when compared with the pure polymers or conventional composites. These include increased modulus and strength, decreased gas permeability, increased solvent and heat resistance and decreased flammability. In addition to their potential applications, PLS nanocomposites are also unique model systems to

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Accession no.697961 Item 360 Polymer Engineering and Science 38, No.8, Aug.1998, p.1351-8 NANOCOMPOSITES BASED ON MONTMORILLONITE AND UNSATURATED POLYESTER Kornmann X; Berglund L A; Sterte J; Giannelis E P Lulea,University of Technology; Cornell University The possibility of synthesising materials with nanocomposite structure based on montmorillonite and unsaturated polyester was studied. The effect of montmorillonite content on mechanical properties was investigated. X-ray and TEM data supported the formation of a partly delaminated nanocomposite material. Montmorillonite was derived from bentonite, purified, activated by sodium ions and mixed with reactive unsaturated polyester. 27 refs. SCANDINAVIA; SWEDEN; USA; WESTERN EUROPE

Accession no.697284 Item 361 Polymer 39, No.25, 1998, p.6423-8 PREPARATION AND EVALUATION OF COMPOSITES FROM MONTMORILLONITE AND SOME HETEROCYCLIC POLYMERS. I: POLY(N-VINYLCARBAZOLE)MONTMORILLONITE NANOCOMPOSITE SYSTEM Biswas M; Ray S S Calcutta,Presidency College Polyvinylcarbazole (PNVC) was prepared from Nvinylcarbazole heated above its melting point (64C) by direct initiation using montmorillonite, and by solution polymerisation with montmorillonite in benzene at 50C. The PNVC was intercalated in the montmorillonite layers. The prepared nanocomposite was characterised by infrared and X-ray spectroscopy, transmission electron microscopy, thermogravimetric analysis and electrical conductivity measurements. The particle size was approximately 33 nanometres. The thermal stability of the composite was superior to that of PNVC, and its electrical conductivity was 10000000000 times greater than that of pure PNVC. 21 refs. INDIA

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Item 362 Polymer Bulletin 41, No.1, July1998, p.107-13 MORPHOLOGY OF POLYMER/SILICATE NANOCOMPOSITES. HIGH DENSITY POLYETHYLENE AND A NITRILE COPOLYMER Jeon H G; Jung H-T; Lee S W; Hudson S D Case Western Reserve University A sodium montmorillonite clay was intercalated to render it organophilic, and then solution blended with either high density polyethylene (HDPE) or a nitrile copolymer, to give nanoscale composites. Investigation by X-ray diffraction and transmission electron microscopy showed the silicate layers to be present in thin stacks, finely dispersed in the polymer matrix. Greater dispersion was observed in the nitrile copolymer, indicating a different degree of physical interaction with the clay. Lamellar crystals of HDPE formed parallel to the silicate layers. 13 refs. USA

Accession no.694370 Item 363 Journal of Applied Polymer Science 69, No.8, 22nd Aug. 1998, p.1557-61 SYNTHESES AND PROPERTIES OF SILICONE RUBBER/ORGANOMONTMORILLONITE HYBRID NANOCOMPOSITES. Shengjie Wang; Chengfen Long; Xinyu Wang; Qiang Li; Zongneng Qi Chinese Academy of Sciences Silicone rubber/organomontmorillonite hybrid nanocomposites were prepared using a melt-intercalation process, and characterised by x-ray diffraction, transmission electron microscopy and thermogravimetric analysis. The organomontmorillonite particles exfoliated to a thickness of approximately 50 nm, and were uniformly dispersed within the silicone rubber matrix. The mechanical properties and thermal stability of the prepared materials were very close to those of aerosilicafilled silicone rubber. 10 refs. CHINA

Accession no.693602 Item 364 Chemistry of Materials 10, No.7, July 1998, p.1820-6 HYBRID ORGANIC-INORGANIC NANOCOMPOSITES: EXFOLIATION OF MAGADIITE NANOLAYERS IN AN ELASTOMERIC EPOXY POLYMER Wang Z; Pinnavaia T J Michigan,State University Organomagadiite intercalates were used to form elastomeric polymer-layered silicate nanocomposites in

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in-situ polymerisation during the thermoset process. Exfoliated structures were observed in the rubbery epoxy matrix. Tensile properties were examined. 35 refs. USA

Accession no.692017 Item 365 Chemistry of Materials 10, No.5, May 1998, p.1440-5 IN SITU SYNTHESIS OF POLYMER-CLAY NANOCOMPOSITES FROM SILICATE GELS Carrado K A; Langqiu Xu Argonne National Laboratory Polymer-containing silicate gels were hydrothermally crystallised to form layered magnesium silicate hectorite clays containing polymers that were incorporated in situ. Gels consisted of silica sol, magnesium hydroxide sol, lithium fluoride and a polymer, e.g. polyvinyl pyrrolidone, hydroxypropylmethylcellulose, PAN, polydimethyldiallylammonium chloride and polyaniline. 26 refs. USA

Accession no.682893 Item 366 Journal of Applied Polymer Science 68, No.12, 20th June 1998, p.1997-2005 CHARACTERISATION OF EPOXY-CLAY HYBRID COMPOSITE PREPARED BY EMULSION POLYMERISATION Lee D C; Jang L W Inha,University Details are given of the direct intercalation of an epoxy resin in the interlayer of sodium ion-montmorillonite by a step type of polymerisation in an aqueous emulsion media. The synthesis and results of structural and thermal characterisations for this hybrid composite are described. 12 refs. KOREA

Accession no.681400 Item 367 Polymer 39, No.12, 1998, p.2651-6 STRUCTURE DETERMINATION OF CLAY/ METHYL METHACRYLATE COPOLYMER INTERLAYER COMPLEXES BY MEANS OF CARBON-13 SOLID STATE N.M.R Forte C; Geppi M; Giamberini S; Ruggieri G; Veracini C A; Mendez B CNR; Pisa,University; Venezuela,Universidad Central Solid state carbon-13 NMR techniques were used to study the interlayer complexes of several methyl methacrylate (MMA)/2-(N-methyl-N,N-diethylammonium iodide)ethyl acrylate (MDEA) copolymers with bentonite and hectorite

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References and Abstracts

smectite clays, synthesised by two different procedures. One was copolymerised within the clay previously functionalised with MDEA and the other was the direct interaction of the preformed MMA/MDEA copolymers with clay swollen in a water/acetonitrile mixture. Information on structure and copolymer dynamics in the inorganic layers, obtained from NMR spectra and relaxation time measurements, together with the interlayer spacings measured by X-ray diffraction and glass transition temperatures obtained by DSC, enabled the authors to determine the structural differences between the various complexes. These differences were correlated with the synthetic methods and the copolymer composition. 14 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; ITALY; VENEZUELA; WESTERN EUROPE

Accession no.680092 Item 368 Kobunshi Ronbunshu 55, No.2, 1998, p.90-5 Japanese HIGH DISPERSION OF SYNTHETIC MICA IN POLYAMIDE 6 MATRIX THROUGH HYDROLYSIS OF CAPROLACTAM WITH ACID Katahira S; Kojima K; Tamura T; Yasue K Hokkaido,University Polyamide 6 nanocomposites with mica were successfully prepared from expandable synthetic mica and caprolactam by accelerating hydrolysis, intercalation and polymerisation of caprolactam with acids. Caprolactam molecules protonated by acid were intercalated between the silicate layers of mica and then polymerised between the layers, which resulted in the cleavage and high dispersion of layers. Bending strength and modulus of the nanocomposites were high and comparable with those of nanocomposites prepared under pressure. 3 refs. JAPAN

Accession no.676309 Item 369 Kobunshi Ronbunshu 55, No.2, 1998, p.83-9 Japanese HIGH DISPERSION OF SYNTHETIC MICA IN POLYAMIDE 6 MATRIX THROUGH HYDROLYSIS OF CAPROLACTAM UNDER HIGH PRESSURE Katahira S; Tamura T; Yasue K Hokkaido,University Nanocomposites with highly dispersed mica layers in a polyamide 6 matrix were prepared by hydrolysis and polymerisation of caprolactam under high pressure and in the presence of expandable mica. Silicate layers of the starting mica were cleaved and highly dispersed into the nylon 6 matrix, and high bending strength and modulus were obtained for the nanocomposites as a result of

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cleaved thin layers with a high aspect ratio and the high dispersion. 11 refs. JAPAN

Accession no.676308 Item 370 Acta Polymerica 49, Nos.2-3, Feb./Mar.1998, p.116-23 NANOCOMPOSITES BASED ON A SYNTHETIC LAYER SILICATE AND POLYAMIDE-12 Reichert P; Kressler J; Thomann R; Muelhaupt R; Stoeppelmann G Albert-Ludwigs,University; EMS Chemie AG Nanocomposites based on a synthetic layer silicate and polyamide-12 were prepared and characterised. Emphasis was placed on the characterisation of the swelling behaviour of the layer silicate in 12-aminolauric acid(ALA), which was studied by wide-angle X-ray scattering(WAXS) measurements. Composites and nanocomposites were then prepared using the layer silicate prior to and after swelling with ALA, respectively. These materials were characterised by TEM, atomic force microscopy, WAXS and mechanical measurements. 29 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; SWITZERLAND; WESTERN EUROPE

Accession no.672040 Item 371 Journal of Polymer Science : Polymer Physics Edition 36, No.4, March 1998, p.673-9 INORGANIC/ORGANIC HOST-GUEST MATERIALS: SURFACE AND INTERCLAY REACTIONS OF STYRENE WITH COPPER(II)EXCHANGED HECTORITE Porter T L; Hagerman M E; Reynolds B P; Eastman M P; Parnell R A Northern Arizona,University; New York,Union College Schenectady The in-situ polymerisation of styrene in Cu(II)exchanged hectorite thin films was investigated. Scanning force microscopy(SFM) images of the polymer surface revealed that the surface PS was generally aggregated into groups of elongated strands. SFM imaging of the interclay regions, in conjunction with X-ray diffraction(XRD) and ESR data, indicated that approximately 20-30% of these regions contained PS, with minimal reduction in the majority of Cu2+ sites observed. XRD data showed little or no intercalation of the monomer into the true intergallery regions. Instead, the polymer probably formed in intercrystallite or planar defect regions. In addition, two distinct phases of polymeric material were found within these defect regions, a highly polymerised PS and a PS form exhibiting greater material stiffness. 28 refs. USA

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Item 372 Journal of Applied Polymer Science 67, No.1, 3rd Jan.1998, p.87-92 PREPARATION AND MECHANICAL PROPERTIES OF POLYPROPYLENE-CLAY HYBRIDS USING A MALEIC ANHYDRIDEMODIFIED POLYPROPYLENE OLIGOMER Hasegawa N; Kawasumi M; Kato M; Usuki A; Okada A Toyota Central R & D Laboratories Inc. PP-clay hybrids(PPCHs) were prepared using a maleic anhydride-modified PP(PP-MA) oligomer as a compatibiliser. PP was melt-blended with organophilic clay which was intercalated with PP-MA. In these PPCHs, the particles of silicate layers were dispersed at the nanometer level. The particles became smaller and were dispersed more uniformly, as the ratio of PP-MA to the clay was increased. The dynamic storage moduli of the PPCHs were higher than that of PP up to 130C. The modulus of the PPCH with 5 wt % clay and 22 wt % PPMA, for example, was 1.8 times higher than that of PP at 80C. As the dispersibility of the clays was improved, the reinforcement effect of the clays increased. 13 refs. JAPAN

Accession no.664533 Item 373 Journal of Applied Polymer Science 66, No.10, 5th Dec.1997, p.143-52 SWELLING AND STATIC-DYNAMIC MECHANICAL BEHAVIOUR OF MICAREINFORCED LINEAR ANS STAR-BRANCHED BR COMPOSITES Nugay N; Kusefoglu S; Erman B Bogazici,University Physical properties of mica-reinforced linear and starbranched BR composites were studied with emphasis given to the effect of silane coupling agent, degree of crosslinking, and degree of mica loading as well as the molecular structure of the BR. The effect of mica on tensile properties and swelling are discussed. 36 refs. TURKEY

Accession no.660725

silicate layers of the clays in the hybrids was investigated by TEM and X-ray diffraction. It was found that there were two important factors in achieving exfoliated and homogeneous dispersion of the layers in the hybrids, i.e. the intercalation capability of the oligomers in the layers and the miscibility of the oligomers with PP. Almost complete hybrids were obtained in the case where the PP-MA had both intercalation capability and miscibility. The hybrids exhibited higher storage moduli compared with those of PP, especially in the temp. range from Tg to 90C. The highest relative storage modulus at 80C of the hybrid based on a mica and the miscible PP-MA was as high as 2.0 to that of PP and was 2.4 to that of the PP/PPMA mixture, which was considered to be the matrix of the PPCH. The effects of the types of clay and oligomers on the dynamic moduli are discussed. 13 refs. JAPAN

Accession no.658751 Item 375 Journal of Applied Polymer Science 66, No.3, 17th Oct.1997, p.573-81 POLYVINYL ALCOHOL-CLAY AND POLYETHYLENE OXIDE-CLAY BLENDS PREPARED USING WATER AS SOLVENT Ogata N; Kawakage S; Ogihara T Fukui,University Montmorillonite(MON) was solvent-cast blended with PVAl and PEO using water as cosolvent. The structure and properties of the blend films were investigated. Using small- and wide-angle X-ray scattering measurements of the blends, the silicate layers of MON were found to be well dispersed individually in the PVAl-MON blends, while the silicate layers in PEO-MON blends were found to exist in the form of a large clay tactoid. It was also found, for both blends, that the silicate layers were parallel to the film surface of the blends and that preferred orientation of polymer crystallites was induced by the presence of MON. The effects of the MON content on the thermal behaviour of the PVAl- and PEO-MON blends were studied using DSC. The influence of geometry of the silicate layers on dynamic behaviour of the blends was also studied. 14 refs. JAPAN

Item 374 Macromolecules 30, No.20, 6th Oct.1997, p.6333-8 PREPARATION AND MECHANICAL PROPERTIES OF POLYPROPYLENE-CLAY HYBRIDS Kawasumi M; Hasegawa N; Kato M; Usuki A; Okada A Toyota Central R & D Laboratories Inc. PP-clay hybrids(PPCH) were prepared by simple meltmixing of three components, i.e. PP, maleic anhydridemodified PP oligomers(PP-MA) and clays intercalated with stearylammonium. The dispersibility of 10A thick

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Accession no.656133 Item 376 Macromolecular Symposia Vol.119, July 1997, p.149-55 MECHANICAL SPECTROSCOPY STUDY ON BIODEGRADABLE SYNTHETIC AND BIOSYNTHETIC ALIPHATIC POLYESTERS Choi H J; Kim J H; Jinho Kim Inha,University Miscibility behaviour and rheological properties with mechanical spectroscopy study of both poly(3-

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References and Abstracts

hydroxybutyrate)/poly(ethylene oxide) and biodegradable synthetic aliphatic polyester/LLDPE were investigated. Rotational rheometers were used to measure the shear viscosity as a function of the shear rate and the oscillating shear flow properties. Dynamic mechanical thermal analysis and DSC were used to measure the thermal properties of the blend systems. 14 refs. SOUTH KOREA

Accession no.653729 Item 377 Journal of Polymer Science : Polymer Chemistry Edition 35, No.11, Aug.1997, p.2289-94 SYNTHESIS AND PROPERTIES OF POLYIMIDE-CLAY HYBRID FILMS Yano K; Usuki A; Okada A Toyota Central R & D Laboratories Inc. Polyimide-clay hybrid films with four different sizes of clay minerals were synthesised to investigate the effect of the size of clay minerals to the properties of the hybrids. Hectorite, saponite, montmorillonite, and synthetic mica were used as clay minerals. Analysis of the hybrid and other properties are described. 10 refs. JAPAN

Accession no.653317 Item 378 Macromolecules 30, No.14, 14th June 1997, p.4097-102 RHEOLOGY OF END-TETHERED POLYMER LAYERED SILICATE NANOCOMPOSITES Krishnamoorti R; Giannelis E P Cornell University The rheology of end-tethered polymer layered silicate nanocomposites was investigated using linear viscoelastic measurements in oscillatory shear with small strain amplitudes. Two systems consisting of poly(epsiloncaprolactone) and nylon-6 with varying amounts of layered silicate (montmorillonite) were examined. Comparisons were drawn with rheology of other intrinsically anisotropic materials, and an attempt was made to explain penomenologically their rich-rheological behaviour. 25 refs. USA

Accession no.653260 Item 379 Patent Number: US 5567758 A 19961022 THERMOPLASTIC POLYESTER RESIN COMPOSITION Kinami N; Okamoto M; Shinoda Y; Sekura T; Yamaguchi A Tokyo Boseki KK; Co-Op Chemical Co.Ltd. Compositions are described comprising thermoplastic polyester resins comprising polyester molecules ending

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in terminal groups, where all or part of the terminal groups are represented by formula -R-SO3L, where R is a divalent aliphatic hydrocarbon having 1-20 carbon atoms and L is an alkali metal; an inorganic compound mixture, which comprises one or more compounds selected from: inorganic compounds consisting of M, Mg, Si, O and F and inorganic compounds consisting of M, Mg and F, where M is an alkali metal. The energy of the composition satisfies the following: U is less than or equal to 1,300 (cal/mole), and sigma times sigmae is less than 280000 cal squared/m power 4, where U is the activation energy, sigma is a lateral surface energy and sigmae is a fold surface energy. JAPAN

Accession no.642613 Item 380 Journal of Applied Polymer Science 64, No.11, 13th June 1997, p.2211-20 STRUCTURE AND THERMAL/MECHANICAL PROPERTIES OF POLY(EPSILONCAPROLACTONE)(PCL)-CLAY BLEND Jimenez G; Ogata N; Kawai H; Ogihara T Fukui,University Montmorillonite was organically modified with distearyldimethylammonium chloride. This organically modified clay(OMON) and PCL were solvent-cast blended with chloroform and the structure and properties of the resulting PCL-clay blends were investigated. It was found that a small amount of OMON in the blend accelerated the crystallisation of PCL, whereas a large amount of the organophilic clay delayed it. It was shown that the silicate layers forming the clay could not be dispersed individually in the PCL blends, i.e. the clay seemed to exist as the tactoids consisting of some silicate layers. These tactoids formed a remarkable geometric structure, their surface planes lying almost parallel to the blend film surface. Furthermore, the tactoids were stacked with insertion of PCL lamellae in the film-thickness direction. Preferred orientation of the PCL crystallites was induced by the presence of the clay. 18 refs. JAPAN

Accession no.640105 Item 381 Patent Number: US 5530052 A 19960625 LAYERED MINERALS AND COMPOSITIONS COMPRISING THE SAME Takekoshi T; Khouri F F; Campbell J R; Jordan T C; Dai K H General Electric Co. Silicate minerals which have undergone a cation exchange with at least one heteroaromatic cation comprising a positively charged organo-substituted heteroatom and/or at least one positively charged heteroatom not part of an aromatic ring with at least one bond having a bond order

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References and Abstracts

greater than one and compositions comprising the same are described. USA

Accession no.625416 Item 382 Macromolecules 29, No. 24, 18th Nov. 1996, p.7910-8 RHEOLOGY OF CONFINED POLYMER MELTS Khare R; de Pablo J J; Yethiraj A Wisconsin-Madison,University The behaviour of confined polymer melts in shear flow is investigated using molecular dynamics simulations. Polymer molecules are modelled as bead-spring chains that interact via repulsive site-site potentials. The fluid is contained between atomistic walls and shear is imparted by moving the walls in opposite directions to simulate planar couette flow. Experimental conditions are simulated by maintaining the walls at a constant temperature. The density, velocity, and temperature profiles during shear flow are monitored and compared to those of simple liquids under similar conditions. For the shear rates investigated, polymeric fluids exhibit a much stronger tendency for slip at the wall-fluid interface than simple fluids. The magnitude of slip increases with increasing shear rate. For short chains the magnitude of slip increases with increasing chain length, but appears to reach an asymptotic value at approximately the entanglement length. The viscosity increases as the film thickness is decreased, in qualitative agreement with surface forces apparatus experiments. The chains stretch and align in the flow direction when sheared. 27 refs. USA

Accession no.622393 Item 383 Journal of Polymer Science : Polymer Physics Edition 35, No.2, 30th Jan.1997, p.389-96 STRUCTURE AND THERMAL/MECHANICAL PROPERTIES OF POLY(L-LACTIDE) Ogata N; Jiminez G; Kawai H; Ogihara T Fukui,University Organophilic montmorillonite was obtained by the reaction of montmorillonite and distearyl-dimethylammonium chloride. The modified clay and poly(L-lactide) were solvent cast blended using chloroform as cosolvent. The structure and mechanical properties of the PLLA-clay blends were investigated. 24 refs. JAPAN

Accession no.622359 Item 384 Journal of Polymer Science : Polymer Physics Edition 35, No.1, 15th Jan.1997, p.59-67 RELAXATIONS OF CONFINED CHAINS IN

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POLYMER NANOCOMPOSITES: GLASS TRANSITION PROPERTIES OF POLYETHYLENE OXIDE INTERCALATED IN MONTMORILLONITE Vaia R A; Sauer B B; Tse O K; Giannelis E P Cornell University; Du Pont de Nemours E.I.,& Co.Inc. The relaxation behaviour of PEO, intercalated in montmorillonite, was studied by DSC and thermally stimulated dielectric depolarisation (or thermally stimulated current, TSC). The materials were synthesised by melt or solution-mediated intercalation. In both intercalates, the PEO chains were confined to about 0.8 nm galleries between the silicate layers. The solution intercalate contained a fraction of unintercalated PEO chains which exhibited a weak and depressed PEO melting endotherm in DSC. In contrast, the melt intercalate was ‘starved’ so that almost all the PEO chains were effectively intercalated. For these melt intercalates, no thermal events were detected by DSC. TSC thermal sampling was used to examine the Tg regions and to estimate the extent of cooperativity of chain motions. The motions of the intercalated PEO chains were inherently non-cooperative relative to the cooperative Tg motions in the amorphous portion of the bulk polymer. This was presumably due to the strong confining effect of the silicate layers on the relaxations of the intercalated polymer. 32 refs. USA

Accession no.621249 Item 385 Journal of Applied Polymer Science 63, No.1, 3rd Jan.1997, p.137-9 SYNTHESIS OF POLYPROPYLENE-CLAY HYBRID Usuki A; Kato M; Okada A; Kurauchi T Toyota Central R & D Laboratories Inc. Results are presented of an investigation of the possibility of insertion of PP into the clay gallery using clays modified with non-polar organic molecules. The organophilic clay used was obtained by a cation-exchange reaction between sodium montmorillonite and the distearyldimethylammonium ion. 11 refs. JAPAN

Accession no.618382 Item 386 Chemistry of Materials 8, No.8, Aug.1996, p.1728-34 STRUCTURE AND DYNAMICS OF POLYMERLAYERED SILICATE NANOCOMPOSITES Krishnamoorti R; Vaia R A; Giannelis E P Cornell University The static and dynamic properties of polymer-layered silicate nanocomposites are discussed in the context of

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References and Abstracts

polymers in confined media. Characterisation was undertaken by TEM, kinetic measurements of meltintercalation, NMR, DSC, and rheological dynamics. Data are given for PS, PEO, siloxane copolymers and nylon 6. 33 refs. USA

Accession no.603764 Item 387 Chemistry of Materials 8, No.8, Aug.1996, p.1597-9 CONDUCTIVITY ANISOTROPY OF POLYPHOSPHAZENE-MONTMORILLONITE COMPOSITE ELECTROLYTES Hutchison J C; Bissessur R; Shriver D F Illinois,Northwestern University The role of the intercalating polymer in long-range ion transport was examined for a polybismethoxyethoxyethoxyphosphazene-sodium montmorillonite composite by an analysis of the temperature-dependent conductivity. The methodology and results of conductivity anisotropy measurements are discussed. 27 refs. USA

Accession no.603759 Item 388 Chemistry of Materials 8, No.8, Aug.1996, p.1584-7 INTERFACIAL EFFECTS ON THE REINFORCEMENT PROPERTIES OF POLYMER-ORGANOCLAY NANOCOMPOSITES Shi H; Lan T; Pinnavaia T J Michigan,State University Details are given of the preparation of epoxy resin-clay composites using polyetheramine as curing agent to form a matrix with a subambient Tg. Tensile properties were examined. 12 refs. USA

Accession no.603758 Item 389 Journal of Applied Polymer Science 61, No.7, 15th Aug.1996, p.1117-22 PREPARATION AND CHARACTERISATION OF PMMA-CLAY HYBRID COMPOSITE BY EMULSION POLYMERISATION Dong Choo Lee; Lee Wook Jang Inha,University Nanocomposites were prepared by a simple technique involving emulsion polymerisation using methyl methacrylate monomer and Na+-montmorillonite. The products were purified by hot toluene extraction and characterised by FTIR, X-ray diffraction, TGA, DSC and tensile testing. A structural investigation confirmed that the products were intercalated with PMMA chain

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molecules oriented parallel to the direction of lamellar layers whose separation was consequently more enlarged than in the polymer-free clay. DSC traces also confirmed the confinement of the polymer in the inorganic layer by exhibiting no observable transition in the thermogram. Both the thermal stability and tensile properties of the products appeared to be markedly enhanced. The iondipole bonding was thought to be the driving force for the introduction and fixation of the organic polymer onto the interfaces of montmorillonite. 9 refs. SOUTH KOREA

Accession no.600813 Item 390 Journal of Materials Science 31, No.13, 1st July 1996, p.3589-96 POLYMER-CLAY NANOCOMPOSITES: FREERADICAL GRAFTING OF PS ON TO ORGANOPHILIC MONTMORILLONITE INTERLAYERS Akelah A; Moet A Tanta,University; Case Western Reserve University Vinyl monomer-montmorillonite intercalates were prepared by a cation exchange process and were grafted with PS. The effect of montmorillonite amounts on the formed PS was determined. Characterisation was undertaken by X-ray diffraction, elemental analysis, and IR spectroscopy. 36 refs. EGYPT; USA

Accession no.598978 Item 391 Journal of Materials Science Letters 15, No.13, 1st July 1996, p.1178-9 SYNTHESIS AND CRYSTALLISATION BEHAVIOUR OF AN INTERCALATED COMPOUND OF PETP AND MICA Okamoto M; Shinoda Y; Okuyama T; Yamaguchi A; Sekura T Toyobo Co.Ltd.; CO-OP Chemical Co.Ltd. Details are given of a PETP-mica compound synthesised by intercalation of ethylene glycol molecules to expandable fluorine mica. The crystallisation behaviour is discussed. 9 refs. JAPAN

Accession no.598945 Item 392 Journal of Materials Science 31, No.12, 15th June 1996, p.3123-7 SYNTHESIS AND CHARACTERISATION OF NOVEL POLYACRYLATE-CLAY SOL-GEL MATERIALS Seckin T; Onal Y; Aksoy I; Yakinci M E Inonu,University

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References and Abstracts

The synthesis of polyacrylate clay composites is described in which trialkyloxy silyl functional groups were hydrolysed and co-condensed to give a molecular composite of clay with polymer. A novel material was developed which was proved to be able to overcome most of the described problems. Free-radical polymerisation of trialkoxy silyl end-capped acrylate with ultrasound in the presence of an inert gas was carried out to yield polymers which have clay contents of 10, 50, 100 mol%wt/wt, respectively. Hydrolysis and co-condensation in the presence of an acid catalyst gave composites in which polymers were covalently bonded. The extent of the reaction leading to network formation was qualitatively followed by FTIR, and X-ray diffraction revealed that the silicate layers of the composite were uniformly dispersed. 15 refs. TURKEY

Accession no.595667 Item 393 Advanced Materials 8, No.1, Jan.1996, p.29-35 POLYMER LAYERED SILICATE NANOCOMPOSITES Giannelis E P Cornell University Polymer nanocomposites with layered silicates as the inorganic phase (reinforcement) are discussed. Particular attention is paid to nanocomposites produced by polymer melt intercalation, a versatile and environmentally benign synthetic approach. Such nanocomposites are shown to exhibit significantly improved stiffness, strength and thermal properties compared with their more conventional counterparts. Miscibility issues and the kinetics of polymer intercalation are also considered. 27 refs. USA

Accession no.580156 Item 394 Macromolecules 28, No.24, 20th Nov.1995, p.8080-5 KINETICS OF POLYMER MELT INTERCALATION Vaia R A; Jandt K D; Kramer E J; Giannelis E P Cornell University The kinetics of PS melt intercalation in organically modified mica-type silicates were studied using X-ray diffraction and TEM. By monitoring the change in the integrated intensity of the basal reflection of the silicate host, the rate of conversion from unintercalated to intercalated silicate was determined at various temperatures and for various molecular weights of PS. Hybrid formation was limited by mass transport into the primary particles of the host silicate and not specifically by diffusion of the polymer chains within the silicate galleries. The activation energy of hybrid formation is

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similar to that previously measured for PS self-diffusion in the melt, implying that the mobility of the polymer chains within the host galleries is at least comparable to that in the melt. Therefore, hybrid formation requires no additional processing time than currently required by conventional polymer processing techniques such as extrusion. 37 refs. USA

Accession no.575964 Item 395 Chemistry of Materials 7, No.11, Nov.1995, p.2144-50 MECHANISM OF CLAY TACTOID EXFOLIATION IN EPOXY-CLAY NANOCOMPOSITES Lan T; Kaviratna P D; Pinnavaia T J Michigan,State University Monolithic epoxy resin exfoliated-clay nanocomposites were prepared by the reaction of alkylammoniumexchanged smectite clays with diglycidyl ether of bisphenol A and phenylenediamine as the curing agent. Preliminary mechanical properties are mentioned. 36 refs. USA

Accession no.569446 Item 396 Chemistry of Materials 7, No.9, Sept.1995, p.1597-600 SYNTHESIS AND PROPERTIES OF NEW POLY(DIMETHYLSILOXANE) NANOCOMPOSITES Burnside S D; Giannelis E P Cornell University Using melt processing, PDMS-silicate nanocomposites were synthesised by first delaminating the silicate in the polymer matrix followed by crosslinking. The nanocomposites decreased swelling in toluene and increased thermal stability. The increased swelling resistance is attributed to strong reinforcement/matrix interactions and the large surface area attainable by delamination and dispersion of the silicate particles in the polymer matrix. 34 refs. USA

Accession no.564137 Item 397 Synthetic Metals 72, No.3, June 1995, p.261-7 POLYPYRROLE-BEARING CONDUCTIVE COMPOSITE PREPARED BY AN INVERTED EMULSION PATHWAY INVOLVING NON-IONIC SURFACTANTS Yue Sun; Ruckenstein E New York,State University

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References and Abstracts

Polypyrrole-rubber composites were prepared in two steps using an inverted emulsion pathway. Several non-ionic surfactants, which are not sensitive to the ionic strength, were used in the inverted pathway. The amount of surfactant needed thus becomes very small compared with that used for the ionic surfactant. The effect of the other preparation conditions, such as the nature of the surfactant and of the solvent used for washing the composite, was also investigated. 18 refs. USA

Accession no.554429 Item 398 Journal of Polymer Science : Polymer Chemistry Edition 33, No.7, May 1995, p.1047-57 SYNTHESIS AND BARRIER PROPERTIES OF POLY(EPSILON-CAPROLACTONE)-LAYERED SILICATE NANOCOMPOSITES Messersmith P B; Giannelis E P Cornell University A polymer-ceramic nanocomposite was synthesised which consisted of well-dispersed, two-dimensional layers of an organically modified mica-type silicate(MTS) within a degradable poly-epsilon-caprolactone matrix. A protonated amino acid derivative of MTS was used to promote delamination/dispersion of the host layers and initiate ring-opening polymerisation of epsiloncaprolactone monomer, resulting in poly-epsiloncaprolactone chains that were ionically bound to the silicate layers. The polymer chains could be released from the silicate surface by a reverse ion-exchange reaction and were shown to be spectroscopically similar to pure poly-epsilon-caprolactone. Thick films of the polymer nanocomposite exhibited a significant reduction in water vapour permeability that showed a linear dependence on silicate content. The permeability of nanocomposite containing as low as 4.8% silicate by volume was reduced by nearly an order of magnitude compared with pure polyepsilon-caprolactone. 64 refs. USA

Accession no.551767

and TEM. It was shown that the bar had a triple layer structure consisting of surface, intermediate and middle layers which had different preferred orientations. In the surface layer, both the silicate monolayers and the chain axes of nylon-6 crystallites were parallel to the bar surface, though the latter were randomly oriented within the plane. In the intermediate layer, the silicate monolayers remained parallel to the bar surface but the nylon-6 crystallites rotated by 90 degrees so that the chain axes would be perpendicular to the bar surface or the silicate monolayers. In the middle layer, the silicate monolayers were randomly oriented around the flow axis of the NCH bar, while remaining parallel to it, and the nylon crystallites were randomly oriented around the flow axis while keeping their chain axes perpendicular to the silicate monolayers. It could be concluded that such preferred orientation of nylon-6 crystallites was induced by the clay because the crystallites in the pure nylon-6 bar had no preferred orientation. 16 refs. JAPAN

Accession no.551743 Item 400 Journal of Polymer Science : Polymer Physics Edition 32, No.4, March 1994, p.625-30 FINE STRUCTURE OF NYLON-6-CLAY HYBRID Kojima Y; Usuki A; Kawasumi M; Okada A; Kurauchi T; Kamigaito O; Kaji K Toyota Central R & D Laboratories Inc.; Kyoto,University Nylon-6-clay hybrid (NCH) is a molecular composite of nylon-6 in which silicate monolayers of montmorillonite are uniformly dispersed in the nylon-6 matrix. Using Xray diffraction and transmission electron micrography, it was shown that both the the silicate layers and the nylon6 crystallites (gamma-form) in NCH film had planar orientation, and the chain axes of nylon-6 crystallites were parallel to the film surface. The orientation of chain axes of nylon-6 crystallite increased with montmorillonite content, but the planar orientation of the silicate layers was independent of montmorillonite content. The results were discussed. 11 refs. JAPAN

Item 399 Journal of Polymer Science : Polymer Physics Edition 33, No.7, May 1995, p.1039-45 NOVEL PREFERRED ORIENTATION IN INJECTION-MOULDED NYLON-6/CLAY HYBRID Kojima Y; Usuki A; Kawasumi M; Okada A; Kurauchi T; Kamigaito O; Kaji K Toyota Central R & D Laboratories Inc.; Kyoto,University The preferred orientation of montmorillonite and nylon6 crystallites in a thick injection-moulded bar of nylon-6/ clay hybrid(NCH) was investigated by X-ray diffraction

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Accession no.548607 Item 401 Chemistry of Materials 7, No.3, March 1995, p.562-71 TWO-DIMENSIONAL NANOCOMPOSITES: ALTERNATING INORGANIC POLYMER LAYERS IN ZIRCONIUM PHOSPHATE Yi Ding; Jones D J; Mairele-Torres P; Roziere J Montpellier,University The preparation of a number of organozirconium phosphate composites is described. The alpha,omegaamino acid intercalation compounds are temporally and

147

References and Abstracts

chemically stable, but their main interest lies in their use as precursors for intercalation processes and for polymerisation reactions in-situ, with formation, e.g. of the first nylon-6 zirconium phosphate hybrid. 46 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; WESTERN EUROPE

Accession no.547745 Item 402 Advanced Materials 7, No.2, Feb.1995, p.154-6 NEW POLYMER ELECTROLYTE NANOCOMPOSITES: MELT INTERCALATION OF POLYETHYLENE OXIDE IN MICA-TYPE SILICATES Vaia R A; Vasudevan S; Krawiec W; Scanlon L G; Giannelis E P Cornell University; Wright-Patterson Air Force Base The direct polymer intercalation of PEO in Na+ or Li+exchanged layered silicates, for preparation of polymer electrolyte nanocomposites, is described and the properties of the resulting nanocomposites are discussed. It is shown that intercalation of the polymer chains in the silicate galleries greatly suppress their tendency to crystallise. The conductivity of PEO/Li+-montmorillonite nanocomposite containing 40 wt % PEO is 0.0000016 S/ cm at 30C and exhibits a weak temp. dependence with an activation energy of 2.8 kcal/mol. 24 refs. USA

Accession no.547358 Item 403 Chemistry of Materials 6, No.12, Dec.1994, p.2216-9 CLAY-REINFORCED EPOXY NANOCOMPOSITES Lan T; Pinnavaia T J Michigan,State University Details are given of the synthesis and mechanical properties of clay-reinforced epoxy resin nanocomposites. Phenylenediamine was used as curing agent. 25 refs. USA

Accession no.538609 Item 404 Journal of Applied Polymer Science 55, No.1, 3rd Jan.1995, p.119-23 INTERACTION ON NYLON 6-CLAY SURFACE AND MECHANICAL PROPERTIES OF NYLON 6-CLAY HYBRID Usuki A; Koiwai A; Kojima Y; Kawasumi M; Okada A; Kurauchi T; Kamigaito O Toyota Central R & D Laboratories Inc. Nylon 6-clay hybrid materials were synthesised using montmorillonite, saponite, hectorite, and synthetic mica.

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Mechanical properties of their injection moulded specimens were measured. 6 refs. JAPAN

Accession no.537463 Item 405 Chemistry of Materials 6, No.10, Oct.1994, p.1719-25 SYNTHESIS AND CHARACTERISATION OF LAYERED SILICATE-EPOXY NANOCOMPOSITES Messersmith P B; Giannelis E P Cornell University An epoxy-silicate nanocomposite was prepared by dispersing an organically modified mica-type silicate in an epoxy resin and curing in the presence of nadic methyl anhydride, benzyldimethylamine or boron trifluoride monoethylamine at 100-200C. Molecular dispersion of the layered silicate within the crosslinked epoxy matrix was verified using X-ray diffraction and TEM, revealing layer spacings of 100A or more and good wetting of the silicate surface by the epoxy matrix. The curing reaction appeared to involve the hydroxyethyl groups of the alkylammonium ions located in the galleries of the organically modified silicate, which participated in the crosslinking reaction and resulted in direct attachment of the polymer network to the molecularly dispersed silicate layers. The nanocomposite exhibited a broadened Tg at slightly higher temp. than the unmodified epoxy. Furthermore, the dynamic storage modulus of the nanocomposite containing 4 vol % silicate was approximately 58% higher in the glassy region and 450% higher in the rubbery plateau region compared with the unmodified epoxy. 49 refs. USA

Accession no.534399 Item 406 Chemistry of Materials 6, No.5, May 1994, p.573-5 NATURE OF POLYIMIDE-CLAY HYBRID COMPOSITES Lan T; Kaviratna D; Pinnavaia T J Michigan,State University Polyimide-clay hybrid composites were prepared by intercalation of a polyamic acid in the galleries of a series of montmorillonites and subsequent conversion of the polyamic acid to polyimide. The composites were studied by X-ray diffraction and it was found that much of the clay was retained in an ordered intercalated state upon hybrid composition formation. The carbon dioxide permeability of the composites was also studied and it was shown that, despite the presence of a substantial fraction of highly ordered clay aggregates, the barrier film properties at low clay loadings were good. 21 refs. USA

Accession no.514226

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References and Abstracts

Item 407 Chemistry of Materials 6, No.4, April 1994, p.468-74 CLAY-POLYMER NANOCOMPOSITES FORMED FROM ACIDIC DERIVATIVES OF MONTMORILLONITE AND AN EPOXY RESIN Wang M S; Pinnavaia T J Michigan,State University A new type of clay-polymer nanocomposite was prepared by spontaneous self-polymerisation of an epoxy resin, the diglycidyl ether of bisphenol A (DGEBA), and the concomitant delamination (exfoliation) of acidic forms of montmorillonite at elevated temperatures. The epoxide polymerisation-clay delamination temperature (PDT) was dependent on the heating rate and the nature of the clayexchange cation. 16 refs. USA

Accession no.510626 Item 408 Chemistry of Materials 5, No.12, Dec.1993, p.1694-6 SYNTHESIS AND PROPERTIES OF TWODIMENSIONAL NANOSTRUCTURES BY DIRECT INTERCALATION OF POLYMER MELTS IN LAYERED SILICATES Vaia R A; Ishii H; Giannelis E P Cornell University A versatile synthetic approach is reported which is based on direct polymer melt intercalation, based on a predominantly enthalpic mechanism. Using an organically modified layered silicate, different polymers of varying degrees of polarity and crystallinity have been intercalated, including for the first time PS. A report is given on the properties of the intercalated polymers by concentrating on the PS-organosilicate hybrid. The results have important implications not only in the synthesis and properties of organic/inorganic nanostructures but also in diverse areas where ultrathin polymer films confined between are involved. These include filler-polymer interactions in polymer composites, polymer adhesives, lubricants, and interfacial agents between immiscible phases. 25 refs.

A biodegradable nanocomposite consisting of polyepsilon-caprolactone-intercalated fluorohectorite embedded in a matrix of the same polymer was synthesised by heating the monomer intercalated silicate in excess epsilon-caprolactone. NMR, IR, DSC and powder X-ray diffraction analyses were used to characterise the nanocomposite. The intercalated polymer was strongly adsorbed within the two-dimensional silicate galleries and did not show the characteristic melting transition of poly-epsilon-caprolactone. 21 refs. USA

Accession no.493193 Item 410 Journal of Polymer Science : Polymer Chemistry Edition 31, No.10, Sept.1993, p.2493-8 SYNTHESIS AND PROPERTIES OF POLYIMIDE-CLAY HYBRID Yano K; Usuki A; Okada A; Kurauchi T; Kamigaito O Toyota Central R & D Laboratories Inc. A polyimide hybrid with montmorillonite clay mineral was synthesised from a dimethylacetamide (DMAC) solution of polyamic acid and a DMAC dispersion of montmorillonite intercalated with an ammonium salt of dodecylamine. In this hybrid, montmorillonite is dispersed homogeneously into the polyimide matrix and oriented parallel to the film surface, this structure showing excellent gas barrier properties. Only 2 wt% addition of montmorillonite brought permeability coefficients of various gases to values less than half of those of ordinary polyimide. This hybrid also has low thermal expansion coefficient. 13 refs. JAPAN

Accession no.491611

Accession no.500889

Item 411 Chemistry of Materials 5, No.6, June 1993, p.835-8 STRUCTURAL, THERMAL, AND ELECTRICAL CHARACTERISATION OF LAYERED NANOCOMPOSITES DERIVED FROM NAMONTMORILLONITE AND POLYETHERS Wu J; Lerner M M Oregon University

Item 409 Chemistry of Materials 5, No.8, Aug.1993, p.1064-6 POLYMER-LAYERED SILICATE NANOCOMPOSITES: IN SITU INTERCALATIVE POLYMERISATION OF EPSILON-CAPROLACTONE IN LAYERED SILICATES Messersmith P B; Giannelis E P Cornell University

Nanocomposites were prepared from Na-montmorillonite and PEO or poly(oxymethylene oligo(oxyethylene)) and characterised by X-ray diffraction, impedance spectroscopy, DTA and TGA. Two ordered phases with intersheet spacings of 13.6 and 17.7A, accommodating either single or double polymer layers within the montmorillonite galleries, were formed with polymer/Namontmorillonite stoichiometries of 0.15 and 0.30 g/g, respectively. Materials prepared with intermediate stoichiometries yielded diffraction profiles characteristic of solid solutions of these two phases. The details of

USA

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References and Abstracts

composition and structure provided strong evidence that the polymer conformation was not helical as in crystalline PEO but more closely resembled an adsorbed layer. Sodium salts could also be incorporated into the polyether/ clay phases. The double-layer phase exhibited a maximum stable ionic conductivity between 0.00001 and 0.000001 S/cm at 520K. 13 refs. USA

Accession no.489206 Item 412 Journal of Applied Polymer Science 49, No.7, 15th Aug.1993, p.1259-64 SORPTION OF WATER IN NYLON 6-CLAY HYBRID Kojima Y; Usuki A; Kawasumi M; Okada A; Kurauchi T; Kamigaito O Toyota Central R & D Laboratories Inc. Various nylon 6-clay hybrids, such as molecular composites of nylon 6 and silicate layers of montmorillonite or saponite, were synthesised. Sorption of water in the hybrids was measured to estimate the resistance to water permeation. The diffusion coefficient and the partition coefficient were obtained from the sorption curves. Montmorillonite improved the resistance to water permeation of nylon 6 more than saponite. Diffusion coefficients decreased with an increase in the amount of clay minerals. An equation relating diffusion coefficient to composition was obtained. 11 refs. JAPAN

Accession no.488971 Item 413 Journal of Polymer Science : Polymer Chemistry Edition 31, No.7, June 1993, p.1755-8 ONE-POT SYNTHESIS OF NYLON 6-CLAY HYBRID Kojima Y; Usuki A; Kawasumi M; Okada A; Kurauchi T; Kamigaito O Toyota Central R & D Laboratories Inc. Nylon 6-clay hybrids were synthesised by polymerising mixtures of epsilon-caprolactam and mixtures of 6aminocaproic acid (accelerator) in the presence of water, montmorillonite, and various acids. Tensile and heat distortion tests were carried out to estimate the mechanical properties. 8 refs. JAPAN

Accession no.481706 Item 414 Journal of Materials Research 8, No.5, May 1993, p.1185 MECHANICAL PROPERTIES OF NYLON 6CLAY HYBRID

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Kojima Y; Usuki A; Kawasumi M; Okada A; Fukushima Y; Kurauchi T; Kamigaito O Toyota Central R & D Laboratories Inc. Various nylon 6-clay hybrids, such as molecular composites of nylon 6 and silicate layers of montmorillonite and saponite, NCHs and NCHPs, respectively, were synthesised. Tensile, flexural, impact and heat distortion tests were carried out. NCH was found to be superior in strength and modulus and comparable in impact strength to nylon 6. The heat distortion temp.(NDT) of NCH (montmorillonite 4.7 wt %) was 152C, which was 87C higher than that of nylon 6. In NCHP, saponite had a smaller effect on the increase in these mechanical properties. The modulus and HDT of NCH and NCHP increased with an increase in the amount of the clay minerals. It was found that these properties were well described by the contribution of the constrained region calculated from the storage and loss modulus at the Tg. 9 refs. JAPAN

Accession no.478754 Item 415 Journal of Materials Research 8, No.5, May 1993, p.1179-84 SYNTHESIS OF NYLON 6-CLAY HYBRID Usuki A; Kojima Y; Kawasumi M; Okada A; Fukushima Y; Kurauchi T; Kamigaito O Toyota Central R & D Laboratories Inc. epsilon-Caprolactam was polymerised in the interlayer of montmorillonite, a layered silicate, yielding a nylon 6clay hybrid(NCH). X-ray diffraction and TEM studies showed that the NCH was a real ‘polymer-based molecular composite’ or ‘nanometer composite’. Endgroup analysis of the nylon in NCH demonstrated that NH3+ ions were present in NCH and interacted in the montmorillonite layers, that COOH end groups in 12montmorillonite initiated polymerisation of epsiloncaprolactam and that the ratio of the bonded nylon to nonbonded nylon increased with increasing montmorillonite content in NCH. 8 refs. JAPAN

Accession no.478753 Item 416 Journal of Polymer Science : Polymer Chemistry Edition 31, No.4, 30th March 1993, p.983-6 SYNTHESIS OF NYLON-6-CLAY HYBRID BY MONTMORILLONITE INTERCALATED WITH EPSILON-CAPROLACTAM Kojima T; Usuki A; Kawasumi M; Okada A; Kurauchi T; Kamigaito O Toyota Central R & D Laboratories Inc. Montmorillonite intercalated with epsilon-caprolactam was prepared from clay, water, caprolactam and

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References and Abstracts

hydrochloric acid. X-ray diffraction revealed that the chain axes of the epsilon-caprolactam were parallel to the montmorillonite plates. The intercalated montmorillonite was swollen by molten epsiloncaprolactam at 200C. Epsilon-caprolactam and 6aminocaproic acid (accelerator) were polymerised with the intercalated montmorillonite at 160C for 6h, yielding a nylon-6-clay hybrid. X-ray diffraction and TEM revealed that the silicate layers of the hybrid were uniformly dispersed in the nylon 6 matrix. Mechanical properties of the hybrid were improved. 8 refs. JAPAN

Accession no.474394 Item 417 Chemistry of Materials 4,No.6,Nov/Dec.1992,p.1395-403 POLYETHYLENE OXIDE-SILICATE INTERCALATION MATERIALS Aranda P; Ruiz-Hitzky E Instituto de Ciencia de Materiales The results are reported of a study of the intercalculation of PEO into 2:1 charged phyllosilicates (montmorillonite and hectorite). Typical conductivity values associated with the motion of the intracrystalline cations contained in the PEO/montmorillonite materials are given. A model for the PEO-silicate compounds, based on the preservation of the helical structure of the polymer, is presented, which is supported by IR, NMR and X-ray diffraction data. 47 refs. EUROPEAN COMMUNITY; SPAIN; WESTERN EUROPE

Accession no.470911 Item 418 Makromolekulare Chemie 192,No.8,Aug.1991,p.1715-25 SYNTHESIS AND PROPERTIES OF QUASIRIGID POLYESTERS CONTAINING DISUBSTITUTED TETRAHYDROPYRAN RINGS IN THEIR MAIN CHAIN Atsumi M;Okada M;Sumitomo H;Yamada S NAGOYA,UNIVERSITY

Item 419 - REISSUE OF ABS.05024 pp.XIV,255. USD.24.50. 9ins. 25/6/75. R.ROOM. 95 MECHANICAL PROPERTIES OF POLYMERS AND COMPOSITES. VOL.1. NEW YORK, MARCEL DEKKER INC., 1974 NIELSEN L E This volume outlines the general mechanical properties of polymers and composites. Particulate-filled polymers, fibre filled composites, foams, high impact polymers and poly blends are considered in relation to: stress-strain properties; chemical structure; conversion factors for moduli, stress and viscosity; glass transition temps. And melting points; and relationships betweentengineering moduli and tensor moduli. 393 refs. Accession no.12239 Item 420 ACS, MACROMOLECULAR SECRETARIAT. SYMPOSIUM, CHICAGO, ILL., AUG.1973 APPLIED POLYMER SYMPOSIA 25,1974, P.81-8. CONFER.42C391 POLYMERISATION OF MONOMOLECULAR LAYERS ADSORBED ON MONTMORILLONITE: CYCLISATION IN POLYACRYLONITRILE AND POLYMETHACRYLONITRILE BLUMSTEIN R; BLUMSTEIN A; PARIKH K K A report is presented on the extensive cyclisation to polyimine in PAN and pman prepared through free-radical initiation in the case of monolayers of an and man adsorbed on the surface of a sodium or a calcium montmorillonite. 15 refs. Accession no.3614

A polyester composed of linked tetrahydropyran rings was synthesised by direct polycondensation of hydroxytetrahydropyran carboxylic acid using methylchloropyridinium iodide or triphenylphosphine and hexachloroethane as condensing agents in pyridine at 25 or 50C. The hydroxycarboxylic acid was polymerised also with dibutyltin oxide. Some properties were examined. 11 refs. JAPAN

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References and Abstracts

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Subject Index

Subject Index A ABRASION RESISTANCE, 5 34 42 ABSORPTION, 259 289 392 ACRYLAMIDE, 286 ACRYLIC POLYMER, 5 104 320 341 389 ACRYLONITRILE, 294 ACRYLONITRILE-STYRENE COPOLYMER, 294 ADHESION, 24 336 343 ADSORPTION, 27 29 82 194 293 331 411 AGGREGATE, 283 406 AGGREGATION, 64 66 118 157 263 297 371 ALIGNMENT, 1 89 ALKYLAMMONIUM GROUP, 46 270 356 ALKYLAMMONIUM ION, 152 AMINE, 38 95 96 116 126 175 201 206 279 319 341 346 405 AMINE-TERMINATED, 345 AMINO ACID, 346 401 AMINODODECANOIC ACID, 90 127 182 309 AMINOLAURIC ACID, 370 AMMONIUM COMPOUND, 95 127 195 204 300 310 341 345 374 AMMONIUM ION, 24 71 104 129 169 202 216 277 AMMONIUM PEROXODISULFATE, 306 AMMONIUM SALT, 258 410 ANALYSIS, 6 9 12 13 21 30 31 39 41 52 62 63 71 84 107 108 109 116 118 132 134 138 156 170 188 202 203 219 239 253 277 292 305 315 316 318 322 332 339 377 417 ANISOTROPY, 55 98 157 238 301 334 378 387 APPLICATION, 5 15 20 32 53 56 61 101 114 144 171 230 232 265 270 278 324 345 352 359 402 AQUEOUS, 10 55 83 166 170 246 247 293 300 306 352 ASPECT RATIO, 20 24 111 114 121 168 226 241 334 369 ASSEMBLY, 144 151 319 ATOMIC FORCE MICROSCOPY, 7 41 48 103 116 137 155 231 246 249 255 310 370

AUTOMOTIVE APPLICATION, 15 20 53 61 114 144 230 278 AZOBISISOBUTYRONITRILE, 11 108 240 246

B BARRIER PROPERTIES, 20 24 32 54 59 81 109 114 170 171 182 205 206 232 301 330 341 348 398 406 410 BEER BOTTLE, 20 BENDING STRENGTH, 368 369 BENTONITE, 67 68 311 344 360 367 BENZOXAZINE, 212 BENZYLDIMETHYLAMINE, 405 BIOCOMPOSITE, 352 BIODEGRADABLE, 3 15 20 23 27 29 50 54 88 122 153 161 257 376 409 BIOMATERIAL, 56 376 BIOMEDICAL APPLICATION, 171 270 BIREFRINGENCE, 97 250 305 BISHYDROXYETHYLMETHYL DODECYLAMMONIUM CHLORIDE, 37 BISPHENOL A, 95 116 407 BISPHENOL A DIGLYCIDYL ETHER, 25 249 255 BISPHENOL A POLYCARBONATE, 321 BLEND, 10 30 31 66 142 150 183 197 199 207 208 210 211 216 220 232 257 288 302 339 341 376 383 419 BLENDING, 33 35 46 110 141 203 208 BLISTER PACKAGING, 20 BLOCK COPOLYMER, 12 133 151 310 317 347 BLOW MOULDING, 74 232 349 BLOWN FILM, 58 76 232 BODY PANEL, 230 BOTTLE, 20 232 BRABENDER MIXER, 35 36 127 321 BULK POLYMERISATION, 104 155 178 204 240 341 BUTADIENE-ACRYLONITRILE COPOLYMER, 109 345 BUTADIENE-STYRENE COPOLYMER, 231 296 297

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C CABLE, 186 308 CALCIUM SILICATE, 352 CALCIUM STEARATE, 216 CALORIMETER, 35 36 52 156 169 178 204 303 CALORIMETRY, 38 52 60 199 207 208 209 210 221 222 224 303 CAPILLARY RHEOMETRY, 148 CAPROLACTAM, 84 368 369 413 CARBON 13, 12 84 159 203 332 367 CARBON BLACK, 111 CARBON DIOXIDE, 89 CARBON FIBRE, 144 CARBON-REINFORCED PLASTICS, 111 CAST, 263 380 CASTING, 122 123 153 183 195 383 CATALYST, 102 144 159 196 236 251 334 345 392 CATION, 69 141 221 345 381 417 CATION EXCHANGE, 149 212 241 283 319 381 407 CELLULAR MATERIAL, 78 89 CERAMIC, 398 CHAR, 13 101 141 CHAR FORMATION, 52 110 156 186 CHAR YIELD, 159 264 CHARACTERISATION, 1 2 9 18 29 38 46 48 50 59 60 62 69 70 72 79 80 84 97 98 106 113 117 123 139 140 150 151 155 157 159 166 169 170 178 185 192 193 196 206 218 219 220 224 225 242 246 247 250 254 258 268 274 284 288 289 291 296 311 314 315 316 318 326 330 331 340 341 360 361 363 370 377 378 389 392 405 409 410 411 CHEMICAL MODIFICATION, 14 27 29 46 60 63 101 106 110 115 135 141 158 169 171 185 192 216 226 246 249 250 263 264 270 294 331 342 358 CHEMICAL RESISTANCE, 24 79 289 330 359 CHEMICAL STRUCTURE, 2 23 27 68 93 106 117 128 130 137 141 144 148 149 157 159 175

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Subject Index

176 183 184 185 190 191 193 194 208 212 221 236 239 240 246 247 249 260 269 272 285 290 294 321 339 359 360 361 364 366 367 373 375 419 CHLOROFORM, 153 380 383 CHROMATOGRAPHY, 7 52 84 110 117 119 159 165 170 219 236 246 253 CLARITY, 5 20 55 205 CLOSED CELL, 89 CO-ROTATING, 149 CO-ROTATING EXTRUDER, 79 COATING, 5 144 170 253 COEXTRUSION, 232 COLD DRAWING, 273 COMBUSTION, 13 169 182 COMMERCIAL INFORMATION, 20 COMONOMER, 10 11 246 294 COMPATIBILISER, 4 46 57 63 73 97 99 120 149 165 218 262 274 312 319 347 372 COMPATIBILITY, 53 55 114 240 347 COMPLEX VISCOSITY, 14 63 111 115 226 257 COMPOSITION, 14 28 57 58 73 76 77 79 80 98 99 106 110 111 113 118 145 146 148 149 155 158 159 163 170 180 183 184 185 225 226 229 240 249 250 268 270 274 284 311 312 317 323 342 361 379 381 COMPOSTING, 54 COMPOUNDING, 22 40 95 101 129 134 334 COMPRESSION MOULDING, 109 111 233 COMPUTER SIMULATION, 118 176 194 235 304 382 CONDENSATION POLYMERISATION, 148 150 263 418 CONDUCTION, 209 221 CONDUCTIVE POLYMER, 243 267 333 CONE CALORIMETER, 35 36 52 156 169 178 204 303 COOLING, 110 147 162 179 248 COOLING RATE, 115 138 147 162 COPOLYMER, 159 199 COPOLYMER COMPOSITION, 46 157 294 367 COPOLYMERISATION, 40 119 159 CORROSION RESISTANCE, 170 253

154

COST, 230 278 COUPLING AGENT, 4 343 373 CROSSLINK DENSITY, 172 183 250 307 CROSSLINKING, 94 101 119 146 188 201 249 250 255 275 276 307 308 344 373 396 CRYSTALLINITY, 7 9 24 32 45 67 90 91 93 94 113 115 138 147 154 157 158 160 162 177 179 180 202 203 208 210 217 222 229 233 238 247 248 282 301 316 348 351 371 375 380 399 400 408 CRYSTALLISATION, 7 24 41 45 48 50 67 82 91 93 97 115 129 147 149 154 157 158 160 162 179 180 188 203 217 227 229 233 248 271 350 351 365 380 383 391 402 CURING, 5 26 28 68 96 109 116 137 183 185 212 242 255 273 277 281 298 307 315 356 388 395 403 405 CURING AGENT, 24 26 95 116 183 193 201 249 255 277 307 329 388 403 405 CYANATE, 345 CYANATE ESTER RESIN, 28

D DECABROMODIPHENYL OXIDE, 101 169 DECOMPOSITION, 64 101 182 DECOMPOSITION TEMPERATURE, 64 242 289 322 340 DECYLTRIMETHYLAMMONIUM CHLORIDE, 246 DEFECT, 329 371 DEFORMATION, 24 134 287 355 DEFORMATION TEMPERATURE, 9 25 32 54 181 278 351 DEGRADABLE, 3 15 20 23 27 29 54 88 122 153 161 257 376 DEGRADATION, 70 86 101 125 156 185 246 256 303 308 313 340 342 DEGRADATION TEMPERATURE, 159 246 342 DEGREE OF CRYSTALLINITY, 113 115 147 154 180 210 400 DEGREE OF DISPERSION, 4 35 53 64 73 79 80 81 134 161 185 202 248 258 266 279 294 307 372

DEGREE OF POLYMERISATION, 353 390 394 DEINTERCALATION, 14 DELAMINATION, 63 66 118 132 187 228 327 359 360 383 396 398 407 DENSITY, 89 101 180 305 382 DIAMETER, 111 410 DIAMINE, 95 201 249 277 DIBUTYLTIN DIMETHOXIDE, 102 152 DICHLOROMETHANE, 17 106 142 DIELECTRIC SPECTROSCOPY, 223 DIELECTRIC STRENGTH, 242 DIFFERENTIAL SCANNING CALORIMETRY, 6 7 21 41 66 67 175 188 189 207 210 212 233 238 253 254 274 277 284 316 326 DIFFERENTIAL THERMAL ANALYSIS, 6 7 21 38 41 48 56 60 66 67 71 94 95 97 106 110 116 119 120 128 129 130 138 141 142 148 149 158 159 165 170 175 179 180 185 188 189 193 199 201 207 208 209 212 217 221 222 224 227 233 238 239 246 247 253 254 255 257 260 269 274 277 281 284 298 299 305 315 316 326 338 339 340 342 347 351 366 367 375 376 383 384 386 389 392 407 408 409 411 DIFFRACTION, 6 14 18 19 21 23 25 26 28 30 31 33 36 38 39 41 46 47 48 49 50 52 DIFFRACTION PATTERN, 14 28 46 69 115 118 141 157 170 184 185 207 212 215 217 225 226 240 245 267 270 307 DIFFUSION, 3 17 24 106 168 171 235 DIFFUSION COEFFICIENT, 17 106 181 234 412 DIFFUSION RATE, 193 DIMENSIONAL STABILITY, 74 183 240 278 311 DIMETHYL ACETAMIDE, 206 269 279 410 DIMETHYL HYDROGENATED TALLOW AMMONIUM ION, 67 DIMETHYL HYDROGENATED TALLOW ETHYLHEXYLAMMONIUM, 141 294

© Copyright 2003 Rapra Technology Limited

Subject Index

DIPHENYLMETHANE DIISOCYANATE, 106 184 DISPERSE PHASE, 280 286 DISPERSIBILITY, 148 200 DISPERSING AGENT, 174 DISPERSION, 10 14 22 24 30 34 45 51 52 61 68 73 100 101 112 115 118 123 136 137 140 141 149 158 161 180 185 192 194 207 208 216 218 222 226 228 231 240 241 246 274 283 294 295 296 297 300 302 306 309 315 327 330 335 340 341 342 346 358 359 362 368 369 374 396 398 405 410 DISPERSIVITY, 4 35 53 64 73 79 80 81 134 161 185 202 248 258 266 279 294 307 372 DISTEARYL DIMETHYL AMMONIUM CHLORIDE, 380 383 385 DODECYL TRIMETHYL AMMONIUM BROMIDE, 64 DODECYLAMINE, 200 206 320 410 DODECYLAMMONIUM CHLORIDE, 315 DODECYLTRIMETHYLAMMONIUM BROMIDE, 64 DOMAIN, 30 262 DOMAIN SIZE, 66 DRAWING, 157 383 DUCTILITY, 230 249 DYNAMIC MECHANICAL ANALYSIS, 6 16 26 28 48 51 67 95 97 100 172 208 212 223 237 242 253 256 262 271 274 314 315 316 DYNAMIC MECHANICAL PROPERTIES, 7 9 24 25 33 37 50 51 67 97 100 106 113 172 216 227 262 271 307 323 DYNAMIC MECHANICAL THERMAL ANALYSIS, 7 19 38 72 113 183 196 218 307 376 DYNAMIC MODULUS, 300 317 405 DYNAMIC PROPERTIES, 7 9 24 25 33 37 50 51 67 97 100 106 113 172 216 227 262 271 307 323 335 359 DYNAMIC THERMOMECHANICAL ANALYSIS, 7 19 38 113 183 218 307 376

E E-MODULUS, 24 42 46 76 90 115

135 141 144 149 211 249 266 340 383 ELASTIC MODULUS, 15 24 42 46 76 90 106 115 135 141 144 149 197 211 249 266 340 377 383 ELASTIC PROPERTIES, 8 23 24 45 115 133 183 186 241 257 260 262 273 313 315 317 349 378 ELASTOMER, 15 20 24 33 34 37 51 61 103 109 118 157 159 163 174 196 215 216 231 250 272 296 297 316 329 334 343 345 356 362 363 364 373 381 382 386 396 ELECTRIC CABLE, 186 308 ELECTRICAL CONDUCTIVITY, 69 111 166 190 221 267 280 306 336 361 387 397 402 417 ELECTRICAL PROPERTIES, 69 101 128 144 166 245 267 280 291 306 308 333 336 361 411 417 ELECTRON DISPERSIVE X-RAY ANALYSIS, 7 ELECTRON MICROGRAPH, 14 26 46 111 118 141 148 149 158 169 170 185 217 240 249 250 294 307 342 400 ELECTRON MICROSCOPY, 7 21 30 51 64 136 199 218 225 237 241 261 287 288 355 ELECTRON SPIN RESONANCE, 224 318 371 ELECTRORHEOLOGICAL PROPERTIES, 69 243 291 333 ELEMENTAL ANALYSIS, 118 219 239 390 397 ELONGATION AT BREAK, 7 24 40 45 46 57 64 75 141 142 148 185 204 211 215 231 270 272 279 326 356 397 EMULSION, 10 83 243 246 EMULSION POLYMERISATION, 10 18 69 104 132 167 243 246 267 291 314 340 366 389 397 END GROUP, 329 345 379 ENERGY DISPERSIVE SPECTROSCOPY, 397 ENVIRONMENTAL DEGRADATION, 256 ENVIRONMENTALLY FRIENDLY, 393 EPOXIDISED NR, 216 343 EPOXY ACRYLATE POLYMER, 5 EPOXY RESIN, 24 25 26 30 95 96 116 130 137 143 172 183 193

© Copyright 2003 Rapra Technology Limited

201 249 255 281 283 313 364 366 388 395 403 405 407 EQUILIBRIA, 106 180 250 ETHYLENE COPOLYMER, 46 94 126 134 157 196 199 209 219 226 302 334 ETHYLENE GLYCOL COPOLYMER, 161 209 ETHYLENE OXIDE COPOLYMER, 12 ETHYLENE-PROPYLENE COPOLYMER, 267 ETHYLENE-PROPYLENEDIENE TERPOLYMER, 37 163 ETHYLENE TEREPHTHALATE COPOLYMER, 199 ETHYLENE-MALEIC ANHYDRIDE COPOLYMER, 115 ETHYLENE-VINYL ACETATE COPOLYMER, 33 40 46 49 94 101 127 156 182 186 192 308 ETHYLENE-VINYL ALCOHOL COPOLYMER, 59 76 EXCLUSION CHROMATOGRAPHY, 110 EXFOLIATED, 14 17 26 42 43 45 50 58 74 75 78 79 98 141 145 146 154 163 164 185 194 226 238 240 246 274 311 312 316 321 342 EXFOLIATION, 3 7 9 11 18 24 42 43 45 46 47 50 51 55 58 62 66 75 78 79 83 85 87 94 98 100 104 105 106 108 114 115 116 117 118 120 123 124 126 127 132 134 135 138 145 148 149 154 160 164 174 178 185 187 193 201 203 205 211 216 218 219 226 228 231 239 255 263 266 274 281 288 289 295 300 311 312 319 EXPANDABLE, 358 368 EXPANSION, 7 24 140 254 377 EXPANSION COEFFICIENT, 6 15 28 181 242 254 263 266 273 279 337 346 377 EXTRACTION, 389 EXTRUSION, 22 24 43 58 74 79 80 101 135 148 149 158 165 173 186 192 197 205 208 222 228 256 288 294 319 338 EXTRUSION BLOW MOULDING, 74 EXTRUSION COATING, 32 EXTRUSION INJECTION MOULDING, 238

155

Subject Index

EXTRUSION MIXING, 22 79 80 173 197 208 222

F FABRICATION, 307 FAILURE, 39 44 249 256 FIBRE, 305 FIBRE SPINNING, 148 FILLER DISTRIBUTION, 363 FILM, 1 17 20 32 58 76 136 145 170 185 190 206 232 242 245 248 250 253 254 263 270 279 301 310 375 377 382 383 398 400 410 FLAME RESISTANCE, 141 155 156 214 261 275 311 FLAME RETARDANCE, 52 101 155 156 169 173 186 276 308 FLAMMABILITY, 2 13 24 36 101 110 114 141 155 156 169 182 186 204 205 214 261 275 276 303 308 311 325 359 FLEXIBLE, 242 254 FLEXURAL PROPERTIES, 7 9 19 21 24 28 50 54 74 75 80 103 114 115 141 144 174 183 237 249 294 371 393 414 FLOW, 40 89 235 262 382 399 FLOW BIREFRINGENCE, 293 FLUORINE, 9 205 319 379 FLUOROHECTORITE, 96 127 133 149 182 192 314 409 FLUOROMICA, 7 75 319 FLUOROPOLYMER, 101 FOAM, 78 89 419 FOOD-CONTACT APPLICATION, 20 76 232 FORMULATION, 187 189 FOURIER TRANSFORM INFRARED SPECTROSCOPY, 2 27 29 48 55 68 69 95 118 119 128 139 151 162 170 191 204 207 214 219 221 222 239 242 247 248 256 285 298 322 326 340 342 366 387 389 392 FRACTURE, 24 92 98 249 269 403 FRACTURE MORPHOLOGY, 1 2 4 9 30 38 39 40 54 63 83 93 96 100 127 130 132 137 143 144 151 165 197 200 203 208 209 210 211 218 219 221 222 224 231 244 251 258 266 269 280 282 283 287 289 293 297 298 302 316 325 338 350 351 355 362 363 366 377 380 FRACTURE TOUGHNESS, 28 39

156

92 98 194 249 360 FREE-RADICAL INITIATOR, 11 FREE-RADICAL POLYMERISATION, 47 119 170 246 300 320 323 345 357 392 FREQUENCY, 3 111 115 121 344 378 FUEL, 74 FUEL RESISTANCE, 79 FUMED SILICA, 250 FUNCTIONAL GROUP, 63 294 346 392 FUNCTIONALISATION, 135 198 205 262 300 FUNCTIONALITY, 62 319

G GAS PERMEABILITY, 20 24 54 56 64 76 81 106 136 146 163 171 181 200 206 253 270 359 406 410 GEL, 24 300 344 354 365 GEL PERMEATION CHROMATOGRAPHY, 7 52 84 117 119 159 165 170 219 236 246 253 391 408 GLASS TRANSITION TEMPERATURE, 7 21 24 26 28 47 50 51 58 66 72 75 95 96 118 119 128 135 137 138 140 145 165 183 184 207 208 212 223 224 246 257 263 284 289 290 307 313 314 316 323 326 340 350 351 367 374 376 384 388 405 419 GRAFT COPOLYMER, 46 93 115 149 169 214 226 302 303 347 390 GRAFT POLYMERISATION, 259 302 345 GRAPHITE, 178 GRAVIMETRIC ANALYSIS, 7 18 28 38 39 60 64 107 110 118 132 136 141 148 155 159 170 185 189 199 209 212 214 215 219 220 224 246 253 254 261 274 284 314 322 340 342 361 363

HEAT DISTORTION TEMPERATURE, 9 25 32 50 54 181 205 278 351 413 414 416 HEAT RELEASE, 24 156 303 HEAT RELEASE RATE, 35 36 169 204 275 HEAT RESISTANCE, 3 20 24 28 36 42 47 55 64 97 101 105 107 110 118 136 140 141 146 153 155 156 159 166 168 170 172 178 185 195 204 212 214 220 254 263 269 284 303 311 314 316 337 340 346 357 359 361 HEAT STABILITY, 31 100 123 140 155 200 242 254 284 311 314 335 HEAT TREATMENT, 138 200 269 HECTORITE, 24 164 293 332 365 367 371 377 404 417 HEXADECYLAMINE, 64 206 346 HIGH DENSITY POLYETHYLENE, 43 45 46 57 74 334 349 362 HIGH MODULUS, 335 HIGH MOLECULAR WEIGHT, 85 185 HIGH TEMPERATURE, 242 282 343 HIGH VOLTAGE ELECTRON MICROSCOPY, 287 HOMOGENEOUS, 123 150 327 330 347 374 HYBRID, 119 148 159 185 200 212 217 225 294 322 339 346 363 366 374 385 410 413 414 415 HYBRID COMPOSITE, 148 163 217 256 262 294 305 315 327 340 363 394 400 401 HYBRID POLYMER, 119 159 359 377 408 HYDROGEN BOND, 55 119 161 162 272 292 347 HYDROGENATED, 141 216 228 HYDROLYSIS, 84 265 368 369 392 HYDROPHILIC, 114 167 219 324 HYDROPHOBIC, 29 114 167 219

I H HARDNESS, 34 83 145 183 349 HEAT DEGRADATION, 24 42 48 52 70 84 102 127 131 146 168 182 185 192 196 214 246 254 257 264 271 284 290 300 308 340 342

IMIDISATION, 185 263 342 IMMISCIBLE, 8 35 36 70 182 408 IMPACT PROPERTIES, 7 15 19 24 25 30 103 141 149 197 208 211 237 275 311 351 414 IMPEDANCE SPECTROSCOPY, 170 411

© Copyright 2003 Rapra Technology Limited

Subject Index

IN-SITU, 35 72 84 149 155 170 217 240 246 292 323 342 365 401 409 IN SITU POLYMERISATION, 11 24 31 38 108 120 164 181 185 203 210 240 274 278 286 350 371 INDUCTIVELY COUPLED PLASMA SPECTROMETRY, 118 INITIATOR, 11 62 102 108 152 236 240 246 357 INJECTION MOULDING, 16 24 52 57 84 114 187 233 287 351 399 404 INSERTION POLYMERISATION, 88 INTERACTION, 3 4 55 94 95 135 158 195 197 198 282 307 343 347 351 371 396 408 INTERCALATING AGENT, 170 294 INTERFACIAL ADHESION, 24 87 231 343 INTERFACIAL AGENT, 408 INTERFACIAL FREE ENERGY, 180 INTERFACIAL PROPERTIES, 157 194 282 351 INTERFACIAL TENSION, 87 103 INTERLAMELLAR, 345 INTERLAMELLAR SPACING, 283 INTERLAYER, 170 198 332 357 367 INTERLAYER SPACING, 149 158 240 262 294 321 334 367 INTRINSIC VISCOSITY, 63 121 150 ION EXCHANGE, 81 114 149 212 216 224 241 283 318 319 334 345 381 390 398 IONIC CONDUCTIVITY, 209 221 280 411 IONOMER, 1 83 229 274 331 IR SPECTROSCOPY, 2 27 48 55 68 69 84 95 106 118 119 128 131 139 151 162 170 191 204 212 214 224 239 247 248 250 256 285 298 315 322 326 340 341 343 361 366 390 409 417 418 ISOPRENE-STYRENE COPOLYMER, 317 ISOTHERM, 27 29 331 ISOTHERMAL, 91 97 180

K KAOLIN, 197 349 KAOLINITE, 353 392

L LAMELLA, 93 134 227 238 239 247 256 282 287 340 380 389 LAMINATE, 359 399 LANGIVIN EQUATION, 17 69 106 115 131 133 143 158 170 180 183 184 188 189 194 212 213 LATEX, 12 297 LATTICE, 82 157 247 LAYER, 6 169 170 180 185 194 255 262 270 294 340 342 347 359 367 378 400 401 408 LAYERED STRUCTURE, 14 26 28 50 69 81 88 118 141 149 164 169 170 184 192 225 246 265 270 285 287 307 311 312 316 347 LIGHT DEGRADATION, 214 230 LIGHT MICROSCOPY, 55 LIGHT SCATTERING, 158 227 LIGHT STABILITY, 214 LIQUID CRYSTAL POLYMER, 148 LIVING POLYMERISATION, 152 LLDPE, 334 376 LOADING, 28 110 111 141 159 170 184 262 LOSS TANGENT, 3 7 14 25 28 67 111 115 122 141 146 195 208 216 227 237 257 271 307 311 344 378 414 LOW DENSITY POLYETHYLENE, 57 LOW TEMPERATURE PROPERTIES, 230

M MAGNESIUM SILICATE, 251 365 MAGNETIC PROPERTIES, 367 MALEATED, 14 45 63 98 115 226 MALEIC ANHYDRIDE, 4 24 35 36 45 57 198 226 227 262 372 374 MALEIC ANHYDRIDE COPOLYMER, 46 89 93 134 149 158 169 214 219 226 237 295 302 303 319 MAR RESISTANCE, 278 MASS POLYMERISATION, 104 155 178 204 240 341 MASTERBATCH, 10 22 31 MATERIAL REPLACEMENT, 101 181 186 278 MATRIX, 10 24 83 101 109 110

© Copyright 2003 Rapra Technology Limited

115 118 123 136 148 149 158 159 170 180 226 241 242 294 315 340 347 396 400 410 MATRIX POLYMERISATION, 150 MDI, 106 184 MECHANICAL SPECTRA, 376 MECHANISM, 70 84 86 93 115 149 154 158 176 178 204 246 248 249 256 283 307 358 405 408 MEDICAL APPLICATION, 56 171 270 MEDIUM-DENSITY POLYETHYLENE, 113 MELT, 3 6 31 46 54 63 71 88 97 108 110 134 141 158 160 195 197 203 205 212 262 289 307 319 321 334 339 384 393 402 MELT BLEND, 7 36 66 77 104 126 163 214 295 327 MELT COMPOUNDING, 75 87 115 149 226 288 334 MELT EXTRUSION, 149 226 227 MELT FLOW, 94 121 181 196 382 394 MELT MIXING, 73 77 85 163 198 210 262 294 374 MELT POLYMERISATION, 24 MELT PROCESSING, 57 77 85 86 139 214 226 228 268 274 278 282 396 MELT PROPERTIES, 40 111 112 113 268 311 MELT SPINNING, 305 MELT VISCOSITY, 75 85 112 113 197 198 382 MELTING, 67 148 177 384 409 MELTING POINT, 7 58 89 91 94 126 142 148 153 175 233 324 350 419 MELTING TEMPERATURE, 50 58 138 175 177 180 189 233 METHACRYLATE COPOLYMER, 345 METHACRYLIC ACID COPOLYMER, 94 METHYL ALUMINOXANE, 159 164 196 334 METHYL METHACRYLATE, 240 METHYL METHACRYLATE COPOLYMER, 280 286 310 325 367 METHYL TALLOW BISHYDROXYETHYLAMMONIUM, 294 MICA, 9 50 81 105 120 241 250 254 259 319 358 368 369 373 377 391 394 398 402 404 405

157

Subject Index

MICROCOMPOSITE, 110 127 141 192 MICROGRAPHY, 16 38 199 208 211 218 219 220 MICROPHASE SEPARATION, 151 171 MICROPOROUS, 172 MICROSCOPY, 1 16 34 38 51 97 137 149 199 207 208 211 218 219 220 222 225 227 310 355 371 415 MICROSTRUCTURE, 2 4 9 12 63 70 71 72 94 120 144 153 158 195 225 320 323 MICROVOID, 7 287 MIGRATION, 13 341 MISCIBILITY, 66 120 183 207 257 347 374 376 393 MIXER, 35 36 127 321 MIXING, 3 22 24 35 36 60 63 70 73 77 79 80 109 123 163 173 185 191 197 198 208 210 211 218 219 222 262 274 289 294 297 298 307 374 394 MODIFICATION, 14 27 29 46 60 104 106 110 115 135 141 158 169 171 185 226 246 249 270 294 342 MODIFIED, 9 11 28 30 37 46 62 100 101 106 110 117 184 226 246 249 MODIFIER, 6 103 202 246 312 MODULUS, 81 83 133 148 193 196 206 256 262 263 270 275 278 286 355 359 360 368 369 414 MOISTURE CONTENT, 239 344 MOISTURE RESISTANCE, 131 MOLECULAR CONFIGURATION, 12 71 118 139 194 248 332 352 MOLECULAR DYNAMICS, 176 177 194 359 367 382 394 MOLECULAR INTERACTION, 27 29 194 294 307 339 MOLECULAR MOBILITY, 3 24 MOLECULAR MOTION, 12 340 384 417 MOLECULAR ORIENTATION, 118 217 400 MOLECULAR PACKING, 248 350 MOLECULAR STRUCTURE, 2 23 27 68 93 106 117 128 130 137 141 144 148 149 157 159 175 176 183 184 185 190 191 193 194 208 212 217 221 236 239 240 246 247 249 260 269 272 285 290 294 321 339 359 360 361 364 366 367 373 375 388

158

390 395 400 403 408 411 418 MOLECULAR WEIGHT, 7 14 43 46 52 62 71 84 85 102 124 149 150 164 165 170 253 294 320 353 376 378 390 394 MOLECULAR WEIGHT DISTRIBUTION, 62 124 236 329 MONSANTO RHEOMETER, 343 MOULDING, 109 112 192 230 233 343 MULTILAYER, 20 32 101 225 MULTIWALL, 111 144

N NANOCRYSTAL, 157 NANOFIBRE, 111 144 NANOLAYER, 118 170 216 300 356 NANOPARTICLE, 24 30 73 75 82 92 112 140 145 147 149 151 157 159 196 229 232 233 268 274 312 314 326 351 NANOPHASE, 42 43 44 45 147 161 175 233 314 NANOPOWDER, 79 80 232 NANOSTRUCTURE, 19 36 108 124 173 261 316 323 408 NANOTUBE, 15 20 111 144 NATURAL RUBBER, 216 343 NBR, 109 345 NETWORK, 2 183 241 250 287 356 392 NETWORK STRUCTURE, 133 329 NEUTRON SCATTERING, 293 NITRILE COPOLYMER, 362 NITROGEN-CONTAINING POLYMER, 55 239 265 306 318 331 336 344 353 NORBORNENE COPOLYMER, 151 NOVOLAC RESIN, 2 NUCLEAR MAGNETIC RESONANCE, 2 12 84 106 131 150 159 202 203 236 332 339 367 386 404 409 417 418 NUCLEATING AGENT, 82 93 147 229 274 383 NUCLEATION, 48 115 144 147 149 158 160 180 229 274 NYLON, 24 41 48 85 90 91 92 101 105 114 121 125 150 179 197 202 203 210 211 232 282 358 370 378 413 414 NYLON-12, 7 75 287 309 311 355 370 NYLON-6, 15 16 20 24 25 41 44 84

85 90 91 105 121 125 138 147 162 177 179 197 202 203 213 217 228 232 233 237 238 256 282 288 301 351 358 359 368 369 378 386 399 400 401 404 413 414 415 NYLON-6,6, 20 65 92 129 194 274 324

O OLIGOMER, 117 196 321 372 374 ONE-STEP, 263 ONIUM ION, 126 246 ONIUM SALT, 204 345 OPTICAL CLARITY, 19 170 OPTICAL MICROSCOPY, 50 97 110 137 148 149 158 180 227 233 249 310 OPTICAL PROPERTIES, 2 24 34 40 55 83 97 118 170 185 205 245 250 299 346 410 OPTIMISATION, 43 57 63 79 198 ORGANIC-INORGANIC COMPOSITE, 2 139 157 312 313 314 326 340 ORGANOCLAY, 3 25 32 46 47 64 81 85 86 90 94 95 101 118 121 136 148 169 185 192 193 199 264 288 ORGANOCLAY COMPOUND, 112 113 139 140 145 146 155 161 294 311 312 326 342 363 ORGANOPHILIC, 82 83 105 122 149 153 158 166 170 187 193 206 227 231 240 294 295 300 307 319 327 334 372 377 380 383 ORGANOSILICATE, 50 ORGANOSILOXANE POLYMER, 363 ORIENTATION, 1 74 134 157 188 226 231 233 238 250 256 293 320 324 375 380 399 400 410 OXIDATION, 127 192 214 264 OXIDATIVE COUPLING, 306 OXYDIANILINE, 266 273 335 342 OXYGEN, 3 125 127 170 206 379 OXYGEN PERMEABILITY, 9 59 64 76 146 232 348 OXYGEN SCAVENGER, 20 OXYGEN TRANSMISSION RATE, 20 32 76

P PACKAGING, 20 32 232 PARAMAGNETIC, 178 202 203 367

© Copyright 2003 Rapra Technology Limited

Subject Index

PARTICLE, 10 63 69 158 185 241 262 340 396 PARTICLE SIZE, 2 5 55 83 103 114 158 192 241 244 329 336 337 350 359 361 372 377 PATTERN, 14 46 115 118 158 217 225 255 PERCOLATION THRESHOLD, 111 PERMEABILITY, 20 24 32 54 56 59 64 74 76 79 81 106 136 146 154 163 170 171 181 200 206 232 234 253 270 299 348 377 398 410 PHASE BEHAVIOUR, 183 210 310 326 PHASE IMAGING, 246 PHASE SEPARATION, 30 110 151 171 183 260 326 PHASE STRUCTURE, 1 198 408 PHASE TRANSITION, 7 65 67 177 PHENOLIC RESIN, 2 107 275 298 PHENYLENE DIAMINE, 249 273 335 342 395 403 PHOSPHONIUM COMPOUND, 204 PHOTOCHEMICAL STABILITY, 214 PHOTOELECTRON SPECTROSCOPY, 13 267 PHOTOOXIDATION, 214 PHOTOPOLYMERISATION, 68 PHYSICAL PROPERTIES, 7 58 83 101 142 148 173 175 233 324 343 350 373 PIGMENT, 22 230 PLASTICISER, 15 42 47 60 77 341 PLATELET, 3 85 114 115 194 195 293 POLARISED LIGHT MICROSCOPY, 55 POLARISED OPTICAL MICROSCOPY, 50 110 148 158 180 233 POLYACRYLAMIDE, 344 354 POLYACRYLATE, 5 392 POLYACRYLIC ACID, 259 POLYACRYLONITRILE, 132 365 420 POLYAMIC ACID, 100 200 206 242 260 266 269 290 335 342 406 410 POLYAMIDE, 24 41 48 85 90 91 92 101 105 114 121 125 150 179 197 202 203 210 211 232 282 358 370 378 399 414 415 POLYAMIDE IMIDE, 145

POLYAMIDE-1010, 48 POLYAMIDE-12, 7 75 287 311 370 POLYAMIDE-6, 15 16 20 24 25 41 44 62 84 85 90 91 105 121 125 138 147 162 177 179 197 202 203 213 217 228 232 233 237 238 256 282 288 305 351 358 359 368 369 378 386 399 400 401 404 412 413 414 415 416 POLYAMIDE-6,6, 20 65 92 194 274 POLYANILINE, 166 168 243 244 253 267 291 292 306 333 365 POLYBENZOXAZINE, 212 315 POLYBENZOXAZOLE, 140 269 POLYBUTADIENE, 231 373 POLYBUTYL ACRYLATE, 322 POLYBUTYLENE, 6 171 POLYBUTYLENE TEREPHTHALATE, 135 POLYCAPROLACTAM, 16 25 44 84 90 91 138 147 162 177 179 213 217 228 232 233 237 238 256 351 359 POLYCAPROLACTONE, 3 17 23 31 58 88 102 106 141 152 154 218 338 380 398 409 POLYCARBONATE, 111 117 191 284 POLYCONDENSATION, 148 150 263 418 POLYDIMETHYL SILOXANE, 24 101 241 250 329 359 386 396 POLYDISPERSITY, 285 320 POLYELECTROLYTE, 128 221 304 331 354 402 POLYEPOXIDE, 24 25 26 30 95 96 116 130 137 143 172 183 193 201 249 255 281 283 313 364 366 POLY-EPSILONCAPROLACTAM, 16 25 44 62 84 90 91 138 147 162 177 179 217 228 232 233 237 238 256 351 359 POLYESTER ACRYLATE, 5 POLYESTER RESIN, 34 379 POLYESTER-URETHANE, 34 174 POLYESTERAMIDE, 32 POLYETHER, 195 225 239 247 293 375 384 402 411 POLYETHERIMIDE, 289 POLYETHYLENE, 36 43 45 46 53 57 59 73 74 101 112 113 115 134 164 209 226 251 334 349

© Copyright 2003 Rapra Technology Limited

362 376 POLYETHYLENE GLYCOL, 60 POLYETHYLENE OXIDE, 71 128 139 142 176 195 209 221 239 247 252 257 293 304 332 339 375 376 384 386 402 411 417 POLYETHYLENE TEREPHTHALATE, 20 120 229 274 348 350 391 POLYHEDRAL OLIGOMERIC SILSESQUIOXANE, 157 159 183 POLYHYDROXYALKANOATE, 15 POLYHYDROXYBUTYRATE, 23 257 376 POLYIMIDE, 24 38 100 131 172 185 200 206 242 254 260 266 269 273 279 290 335 337 346 377 406 410 POLYIONENE, 1 83 229 274 331 POLYISOBUTYLENE, 171 POLYISOPRENE, 216 POLYLACTIC ACID, 15 64 POLYLACTIDE, 23 50 54 60 81 110 165 383 POLYLACTONE, 124 380 409 POLYLAUROLACTAM, 7 75 287 311 370 POLYMERIC COMPATIBILISER, 73 99 274 POLYMERISATION, 10 11 17 18 24 31 38 40 47 48 62 68 69 84 88 95 101 102 104 107 108 116 119 124 132 133 138 150 151 152 154 155 159 167 170 178 180 193 204 215 224 236 240 243 246 255 263 267 269 274 278 286 291 292 300 306 314 318 320 321 323 337 340 341 345 346 350 357 366 368 369 371 401 407 413 420 POLYMERISATION CATALYST, 102 159 196 236 251 334 POLYMERISATION INITIATOR, 11 62 102 108 152 236 240 357 398 415 POLYMERISATION MECHANISM, 62 68 102 106 108 157 159 236 251 259 269 338 366 POLYMETHYL METHACRYLATE, 24 30 66 72 104 108 142 170 236 240 246 314 320 323 330 339 341 347 389 POLYORGANOSILOXANE, 241 250 329 363

159

Subject Index

POLYOXYETHYLENE, 128 139 142 176 209 376 POLYPHENYLENE VINYLENE, 328 POLYPHENYLSILSESQUIOXANE, 183 POLYPROPYLENE, 4 14 15 20 24 35 53 80 82 87 89 93 97 98 99 101 149 158 169 173 180 181 187 188 196 197 198 205 208 214 227 262 264 268 271 278 295 303 319 372 374 385 POLYPROPYLENE OXIDE, 225 POLYSILOXANE, 316 363 POLYSTYRENE, 8 10 12 13 24 35 47 52 66 78 104 105 133 155 159 160 167 178 197 204 207 222 235 240 248 276 280 300 303 323 327 340 357 359 371 386 390 394 408 POLYSULFONE, 123 220 POLYUREA-URETHANE, 171 270 POLYURETHANE, 24 34 56 79 83 106 112 118 136 174 184 215 225 272 326 POLYURETHANE ACRYLATE, 68 POLYURETHANE ELASTOMER, 24 356 POLYURETHANE ESTER, 34 174 POLYURETHANE-UREA, 171 270 POLYVINYL ALCOHOL, 189 223 299 352 375 POLYVINYL AMINE, 27 29 POLYVINYL CARBAZOLE, 336 361 POLYVINYL CHLORIDE, 11 18 19 31 42 70 77 101 186 341 POLYVINYL CYANIDE, 132 POLYVINYL ESTER, 39 POLYVINYL FORMAMIDE, 27 29 POLYVINYL PYRIDINE, 150 224 331 POLYVINYL PYRROLIDONE, 55 119 150 239 306 318 353 365 POLYVINYLBENZENE, 8 66 78 155 207 222 323 POLYVINYLCARBAZOLE, 336 361 POLYVINYLIDENE FLUORIDE, 67 PROCESSABILITY, 20 40 218 312 PROCESSING, 1 3 5 19 35 36 43

160

55 86 87 89 110 126 135 143 197 202 217 312 319 321 334 338 374 PROCESSING AID, 173 218 312 PROPYLENE COPOLYMER, 63 89 93 149 158 169 196 214 237 295 302 319 PROTON MAGNETIC RESONANCE, 12 150 203 PYROLYSIS GAS CHROMATOGRAPHY, 341 PYROMELLITIC ANHYDRIDE, 269 273 335 342

Q QUALITY CONTROL, 22 QUATERNARY AMMONIUM, 141 185 194 288 334 346 357 QUATERNARY PHOSPHONIUM SALT, 170

R RADIATION CURING, 5 344 RADICAL POLYMERISATION, 47 170 236 300 320 345 357 420 REACTION CONDITIONS, 28 69 118 159 240 REACTION MECHANISM, 106 118 159 169 185 225 240 294 307 342 REACTIVE BLENDING, 35 208 RECYCLING, 15 73 230 REDOX POLYMERISATION, 224 318 RELAXATION, 25 217 317 384 RELAXATION TIME, 150 317 367 RESISTIVITY, 111 144 RHEOLOGICAL PROPERTIES, 3 5 7 14 23 34 40 45 52 54 61 63 66 69 75 89 94 111 112 113 115 117 121 122 127 130 133 141 150 153 165 167 195 196 198 211 212 218 226 235 244 252 257 260 262 268 277 278 288 291 300 307 309 311 321 333 344 376 378 382 386 RHEOMETER, 153 333 343 376 RING OPENING POLYMERISATION, 17 62 88 102 124 151 152 154 321 ROOM TEMPERATURE, 151 185 353 ROTATIONAL MOULDING, 112 ROTATIONAL RHEOMETER,

153 333 376 RUBBER, 15 24 33 34 37 51 61 103 109 118 157 159 163 174 196 215 216 231 250 272 296 297 316 329 334 343 345 356 362 363 364 373 381 382 386 396 419

S SAPONITE, 118 138 377 404 412 414 SATURATED POLYESTER, 3 23 54 88 122 124 135 148 152 153 161 174 348 376 379 398 409 418 SBR, 231 296 297 SCANNING ELECTRON MICROSCOPY, 2 7 8 15 16 19 21 25 30 33 39 48 52 55 64 66 85 89 107 111 124 131 132 136 148 155 161 192 193 197 199 206 218 228 237 241 244 249 250 251 254 261 269 274 283 286 287 288 289 303 309 314 322 323 326 330 347 350 361 362 363 366 390 394 397 400 SCANNING FORCE MICROSCOPY, 371 SCANNING PROBE MICROSCOPY, 34 SCRATCH RESISTANCE, 5 205 278 SCREW DESIGN, 79 80 SCREW EXTRUDER, 288 SCREW SPEED, 43 58 SECONDARY ION MASS SPECTROSCOPY, 66 SELF-ASSEMBLY, 144 151 319 SELF-POLYMERISATION, 116 407 SEQUENTIAL MIXING, 307 SHEAR, 63 117 217 228 257 262 268 293 307 320 321 SHEAR MODULUS, 164 277 307 311 SHEAR PROPERTIES, 3 51 69 85 122 153 164 167 188 211 217 243 257 291 300 378 SHEAR RATE, 43 69 153 217 218 243 268 359 376 SHEAR STRESS, 69 85 211 243 257 291 SHEAR VISCOSITY, 7 14 23 69 153 195 257 268 307 376 386 SHEET, 27 238 256 331 347 SHEETING, 16 SHRINKAGE, 305 324

© Copyright 2003 Rapra Technology Limited

Subject Index

SILANISATION, 250 SILICONE COPOLYMER, 196 386 SILICONE ELASTOMER, 24 363 SILICONE POLYMER, 316 363 SILOXANE, 101 275 SILSESQUIOXANE, 172 188 236 313 SILSESQUIOXANE COPOLYMER, 119 196 SINGLE SCREW EXTRUDER, 22 228 288 SIZE EXCLUSION CHROMATOGRAPHY, 110 SMALL ANGLE X-RAY SCATTERING, 14 26 66 123 210 217 238 255 274 SMALL-ANGLE, 62 116 383 SMECTITE, 53 81 230 286 304 367 SODIUM MONTMORILLONITE, 19 55 69 70 101 110 167 168 174 209 215 292 SOLUBILITY, 254 329 337 346 348 SOLUTION, 55 70 84 100 185 200 242 247 260 293 307 321 352 384 410 SOLUTION CASTING, 183 SOLUTION POLYMERISATION, 24 104 107 263 269 320 337 SOLUTION PROCESSING, 139 SOLVENT, 24 70 101 153 212 242 252 285 337 343 345 346 375 380 396 397 SOLVENT CASTING, 122 123 153 195 375 383 SOLVENT RESISTANCE, 24 289 330 359 SOLVENTLESS, 205 SONICATION, 185 SPACING, 139 197 255 SPHERULITE, 50 93 158 180 SPINNING, 148 305 367 STABILISER, 77 306 STABILITY, 3 20 24 28 36 42 47 64 97 101 105 110 118 136 140 141 146 153 155 156 159 166 168 170 172 178 185 195 204 212 214 220 254 263 269 284 303 310 311 314 316 337 340 346 357 361 STACKING, 50 247 383 STEARYLAMMONIUM, 158 315 374 STEPS, 15 114 230 STIFFNESS, 19 24 74 115 141 144 174 249 294 371 393 STORAGE MODULUS, 3 6 7 8 14 15 24 25 26 28 33 47 48 50 54

67 95 97 100 111 113 121 122 127 132 135 141 146 158 163 172 183 184 195 208 211 226 227 237 256 257 262 271 295 307 309 311 314 323 372 374 377 378 405 414 STRAIN, 44 48 121 144 216 256 344 STRAIN AT BREAK, 184 249 STRENGTH, 20 144 153 187 194 204 249 263 337 344 346 355 356 359 393 STRESS, 44 69 106 121 149 216 244 256 266 313 STRESS RELAXATION, 313 317 344 STRESS-STRAIN PROPERTIES, 38 85 106 174 189 191 244 250 262 295 340 347 356 386 419 STYRENE, 104 240 307 STYRENE-ACRYLONITRILE COPOLYMER, 218 291 294 STYRENE COPOLYMER, 10 12 133 310 327 STYRENE-ETHYLENE BUTYLENE-STYRENE BLOCK COPOLYMER, 397 STYRENE-ISOPRENE COPOLYMER, 317 SURFACE PROPERTIES, 49 112 130 304 331 371 399 SURFACE TREATMENT, 32 37 102 109 112 240 249 312 315 346 SURFACTANT, 47 66 85 195 207 238 240 248 300 310 312 315 397 SUSPENSION POLYMERISATION, 11 18 47 104 108 246 SWELLING, 160 193 231 238 250 316 335 343 354 370 373 396 SWELLING AGENT, 184 266 309 335 SYNCHROTRON RADIATION, 116 217 SYNDIOTACTIC, 149 159 160 207 222 248 SYNTHESIS, 21 27 28 48 50 62 69 104 106 118 148 150 151 152 154 159 166 167 180 181 184 186 192 193 196 205 206 212 215 225 240 243 246 254 263 270 283 291 306 307 314 316 318 321 326 331 333 334 340 357 359 360 361 363 365 367 377 392 396 397 398 405 407 408 409 410 413 415

© Copyright 2003 Rapra Technology Limited

T TALLOW, 85 95 127 202 216 228 TALLOW AMINE, 7 67 141 TAN DELTA, 24 26 115 132 183 184 307 376 383 TAPPING MODE ATOMIC FORCE MICROSCOPY, 249 TDI, 95 225 TEMPERATURE DEPENDENCE, 43 74 77 102 113 165 176 233 262 267 277 314 377 386 387 391 402 TENSILE PROPERTIES, 7 15 16 21 24 30 33 34 38 40 42 45 46 48 57 58 64 70 73 75 76 77 79 83 90 98 99 115 123 134 136 141 142 144 146 148 149 153 161 163 164 184 185 191 196 199 205 206 208 209 211 215 220 228 237 249 256 262 269 270 272 273 274 279 290 295 305 326 327 338 340 350 351 356 360 364 373 388 389 397 403 404 413 414 416 TEST, 9 13 22 29 30 31 37 39 63 70 71 72 83 100 109 122 123 134 138 200 242 252 269 273 275 290 298 299 302 304 305 308 315 325 335 338 349 351 364 373 376 377 378 386 387 388 390 391 395 397 403 404 413 417 418 TESTING, 101 141 256 303 418 TETRAHYDROFURAN, 70 170 279 THERMAL ANALYSIS, 6 21 39 41 52 107 132 156 188 253 277 316 318 322 THERMAL DEGRADATION, 24 42 48 52 64 70 84 102 127 131 146 168 182 185 192 196 214 246 254 257 264 271 284 290 300 308 340 342 THERMAL EXPANSION, 7 24 140 254 377 THERMAL EXPANSION COEFFICIENT, 6 15 28 181 242 254 263 266 273 279 337 346 377 410 THERMAL PROPERTIES, 2 4 7 9 24 25 28 35 36 39 41 45 47 50 58 65 66 67 82 83 88 91 93 94 96 97 101 106 110 114 120 131 136 137 140 141 144 145 146 148 155 156 159 175 179 180 182 184 189 192 198 199 204 205 210 212 214 242 248 254 261

161

Subject Index

266 269 271 273 279 284 288 289 299 307 311 313 314 315 316 325 335 338 340 349 363 366 375 376 377 380 383 384 388 391 393 404 405 409 410 411 414 THERMAL STABILITY, 3 20 24 28 36 42 47 55 64 97 101 105 107 110 118 136 140 141 146 153 155 156 159 166 168 170 172 178 185 195 204 212 214 220 254 263 269 284 303 311 314 316 337 340 346 357 359 361 389 396 THERMOGRAVIMETRIC ANALYSIS, 7 18 28 31 36 38 39 48 60 64 70 71 84 95 97 100 102 107 110 118 123 132 136 141 148 153 155 159 166 167 168 170 178 185 189 196 199 204 209 212 214 215 219 220 224 239 242 246 247 253 254 261 264 269 274 284 289 299 304 314 315 316 318 322 325 340 342 361 363 364 366 389 396 411 THERMOMECHANICAL ANALYSIS, 254 314 THERMOMECHANICAL PROPERTIES, 130 314 THERMOOXIDATION, 127 192 264 THERMOOXIDATIVE STABILITY, 110 196 THERMOPLASTIC ELASTOMER, 15 20 THERMOSET, 2 5 21 22 24 26 28 30 34 39 61 83 95 96 100 101 106 107 111 112 116 118 119 130 131 133 136 137 143 146 148 157 159 172 183 184 185 193 200 201 206 225 238 240 241 242 246 249 250 253 255 258 261 262 263 266 273 275 277 278 279 281 283 291 292 294 298 307 312 313 329 335 337 340 342 346 347 356 360 364 366 387 388 395 400 403 405 406 407 THICKNESS, 16 101 250 294 332 382 THIN FILM, 185 248 310 382 408 THIN-WALL, 20 TOLUENE, 101 216 231 396 397 TOLUENE DIISOCYANATE, 95 225 TOUGHNESS, 24 254 263 278 337 346 355 356

162

TRANSITION PHENOMENA, 111 112 113 268 311 TRANSLUCENCY, 199 TRANSMISSION ELECTRON MICROSCOPY, 1 4 7 8 14 15 19 21 25 26 30 31 33 34 36 38 39 46 47 49 50 52 54 55 62 63 64 66 70 85 89 93 102 107 117 118 123 124 126 130 131 132 134 136 141 142 148 149 151 153 155 158 160 161 165 167 169 170 174 178 183 185 192 193 195 199 201 204 206 207 208 211 217 218 219 220 222 226 228 231 237 240 241 242 248 249 254 258 260 261 263 266 269 274 283 286 287 288 289 290 294 296 297 298 299 300 302 303 307 309 314 319 321 322 323 325 326 330 335 336 341 342 347 350 351 359 360 361 362 363 370 374 386 390 395 399 400 403 405 407 415 416 TRANSPARENCY, 2 24 55 83 118 254 346 410 TRANSPORT PROPERTIES, 32 106 144 154 176 348 TWIN-SCREW EXTRUDER, 22 79 80 149 173 197 208 228 288 294 TWO-DIMENSIONAL, 115 332 398 401 408

VINYL ALCOHOL COPOLYMER, 126 VINYL CARBAZOLE, 361 VINYL CHLORIDE, 18 VISCOELASTIC PROPERTIES, 8 23 95 133 183 212 257 260 262 273 293 313 315 316 317 378 VISCOSITY, 5 7 14 23 34 45 52 63 69 111 115 117 121 150 153 195 198 211 218 226 257 268 277 307 321 376 419 VISIBLE SPECTROSCOPY, 34 55 170 VOLUME FRACTION, 24 31 63 72 122 138 144 241 242 273 282 305 316

W

ULTRASONIC, 126 392 UNSATURATED POLYESTER, 21 24 34 146 307 360 379 UV SPECTROSCOPY, 34 40 55 170 214 224 318 UV STABILITY, 214 230 UV VIS SPECTROSCOPY, 34 55 170

WATER ABSORPTION, 20 25 197 237 242 304 326 410 WATER CONTENT, 239 344 WATER PERMEABILITY, 32 412 WATER RESISTANCE, 79 83 WATER SOLUBLE, 27 29 WATER VAPOUR, 106 377 WATER VAPOUR PERMEABILITY, 79 154 171 270 398 WATER VAPOUR TRANSMISSION, 32 WEAR RESISTANCE, 5 34 42 WIDE ANGLE, 26 30 39 50 100 106 108 117 158 170 184 217 242 246 305 383 WIDE ANGLE X-RAY SCATTERING, 7 8 60 64 85 149 157 207 210 211 215 216 221 222 233 238 249 254 262 268

V

X

VAPOUR PERMEABILITY, 79 154 171 270 VAPOUR TRANSMISSION, 32 VEHICLE INTERIOR, 230 VEHICLE MIRROR, 144 VEHICLE SHELL, 53 VERMICULITE, 224 318 VIBRATIONAL SPECTROSCOPY, 84 131 212 315 340 341 343 VINYL ACETATE-ETHYLENE COPOLYMER, 182 192

X-RAY PHOTOELECTRON SPECTROSCOPY, 13 267

U

Y YIELD STRENGTH, 185 211 351 YIELD STRESS, 69 106 121 149 244 256 YOUNG’S MODULUS, 15 24 42 46 76 90 106 115 135 141 144 149 197 211 249 266 340 377 383

© Copyright 2003 Rapra Technology Limited

Company Index

Company Index TECHNOLOGY & ECONOMICS, 82 187

A AIST, 120 AKRON,UNIVERSITY, 11 18 30 73 77 92 108 117 194 228 233 246 321 ALBERT-LUDWIGS, UNIVERSITY, 96 149 264 287 309 325 334 355 370 ALBERTA,UNIVERSITY, 344 ANHUI,UNIVERSITY, 119 ANKARA,MIDDLE EAST TECHNICAL UNIVERSITY, 21 ARGONNE NATIONAL LABORATORY, 365 ASPEN SYSTEMS, 255 ATHENS,DEMOCRITOS NATIONAL RESEARCH CENTRE, 331 AUSTIN,UNIVERSITY OF TEXAS, 288 AUSTRALIA,CSIRO, 71 AVERY RESEARCH CENTER, 146

B BARCELONA,UNIVERSITY, 189 BASF AG, 16 BAYREUTH,UNIVERSITY, 16 BEIJING,INSTITUTE OF CHEMISTRY, 208 215 265 337 350 351 BEIJING,RESEARCH INSTITUTE OF PETROLEUM PROCESSING, 251 BEIJING,UNIVERSITY OF CHEMICAL TECHNOLOGY, 107 251 296 297 BELFAST,QUEEN’S UNIVERSITY, 7 75 BELGIUM,CENTRE DE RECHERCHES EN SCIENCES DE MATERIAUX POLYMERES, 152 BELL HELICOPTER TEXTRON INC., 201 BOGAZICI,UNIVERSITY, 250 373 BROOKLYN,POLYTECHNIC UNIVERSITY, 13 104 BUDAPEST,INSTITUTE OF CHEMISTRY, 82 BUDAPEST,UNIVERSITY OF

CSIC, 189 223 349 CSIRO, 137 139 328

C

D

CALCUTTA,PRESIDENCY COLLEGE, 306 336 361 CALIFORNIA,STATE UNIVERSITY, 57 CAMPINAS,UNIVERSIDADE, 1 CANADA,NATIONAL RESEARCH COUNCIL, 44 90 91 213 CARNEGIE-MELLON UNIVERSITY, 23 122 153 167 195 252 257 291 333 CASE WESTERN RESERVE UNIVERSITY, 175 213 300 348 362 390 CHANGCHUN,INSTITUTE OF APPLIED CHEMISTRY, 65 CHINA,UNIVERSITY OF SCIENCE & TECHNOLOGY, 225 CHINESE ACADEMY OF SCIENCES, 25 180 237 281 346 363 CHONBUK,NATIONAL UNIVERSITY, 109 CHONNAM,NATIONAL UNIVERSITY, 218 CHULALONGKORN, UNIVERSITY, 242 CHUNG YUAN UNIVERSITY, 47 170 253 261 CHUNGNAM,NATIONAL UNIVERSITY, 109 CIDAUT, 4 CINCINNATI,UNIVERSITY, 103 123 216 220 CNR, 367 CNRS, 68 CO-OP CHEMICAL CO.LTD., 379 391 CONNECTICUT,UNIVERSITY, 256 COPERION CORP., 80 COPERION WERNER & PFLEIDERER GMBH & CO.KG, 22 CORNELL UNIVERSITY, 8 14 130 235 285 303 304 314 329 359 360 378 384 386 393 394 396 398 402 405 408 409 CRESMAP, 31 62 88 124

DANKOOK,UNIVERSITY, 198 DAYTON,UNIVERSITY, 26 28 DENMARK,TECHNICAL UNIVERSITY, 121 DOW AUTOMOTIVE, 278 DOW CHEMICAL CO., 164 181 278 DRESDEN,INSTITUTE OF POLYMER RESEARCH, 87 DU PONT DE NEMOURS E.I.,& CO.INC., 384 DUPONT CANADA INC., 324

© Copyright 2003 Rapra Technology Limited

E EASTERN MICHIGAN,UNIVERSITY, 34 EINDHOVEN,UNIVERSITY OF TECHNOLOGY, 287 309 EMS CHEMIE AG, 309 311 370 EQUISTAR CHEMICALS LP, 103 ETH ZURICH, 241 EXXON RESEARCH & ENGINEERING CO., 343 EXXONMOBIL CHEMICAL CO., 94

F FORD MOTOR CO., 53 FREIBURG MATERIALSFORSCHUNGSZENTRUM, 231 FREIBURG,INSTITUT FUR MAKROMOLEKULARE CHEMIE, 319 FREIBURG,UNIVERSITY, 51 311 344 FREIBURGER MATERIALFORSCHUNGSZENTRUM, 182 192 264 309 319 334 FUDAN,UNIVERSITY, 34 FUKUI,UNIVERSITY, 375 380 383

G GE CORPORATE R & D, 135

163

Company Index

GENERAL ELECTRIC CO., 381 GENERAL MOTORS CORP., 230 GENOA,UNIVERSITY, 150 GENOVA’ISTITUTO DI STUDI CHIMICO-FISICI DI MACROMOL.SINT.E NAT., 127 GKSS-RESEARCH CENTRE, 1 GREAT LAKES CHEMICAL CORP., 52

H HALLE,MARTIN-LUTHERUNIVERSITAT, 287 309 311 355 HAN YANG,UNIVERSITY, 46 HANGZHOU,ZHEJIANG UNIVERSITY, 281 HANNAM,UNIVERSITY, 66 94 134 HANOI,INSTITUTE OF CHEMISTRY, 216 HANSE CHEMIE AG, 5 HEBEI,UNIVERSITY OF TECHNOLOGY, 49 161 HEILONGJIANG,ACADEMY OF SCIENCES, 344 HOECHST CORP., 348 HOKKAIDO,UNIVERSITY, 358 368 369 HONEYWELL INTERNATIONAL INC., 232 HOUSTON,UNIVERSITY, 133 210 317 HUAQIAO,UNIVERSITY, 259 330 341 HUNG-KUANG,UNIVERSITY, 2 HUNGARIAN ACADEMY OF SCIENCES, 187 HYBRID PLASTICS, 173 313 HYPERLAST LTD., 184

I I-SHOU UNIVERSITY, 138 254 ICI INDIA LTD., 343 ILLINOIS,NORTHWESTERN UNIVERSITY, 387 ILLINOIS,UNIVERSITY, 352 INDIA,NATIONAL CHEMICAL LABORATORY, 97 268 INDIAN INSTITUTE OF TECHNOLOGY, 33 224 318 343 INHA,UNIVERSITY, 23 69 122 142 153 167 195 243 252 257 267 291 333 340 366 376 389

164

INONU,UNIVERSITY, 392 INSTITUT NATIONAL DES SCIENCES APPLIQUEES, 238 INSTITUTO DE CIENCIA DE MATERIALES, 417 INSTITUTO DE CIENCIA Y TECNOLOGIA DE POLIMEROS, 24 IOWA STATE UNIVERSITY, 12 ISRAEL PLASTICS & RUBBER CENTER, 74

J JERUSALEM,HEBREW UNIVERSITY, 13

K KABELWERK EUPEN AG, 101 156 186 KAISERSLAUTERN, UNIVERSITY, 349 KANGWON,NATIONAL UNIVERSITY, 206 KARACHI,UNIVERSITY, 260 KINGSTON,QUEEN’S UNIVERSITY, 45 115 KOREA,ADVANCED INSTITUTE OF SCIENCE & TECHNOLOGY, 14 55 132 134 219 226 244 245 294 298 307 357 KOREA,INSTITUTE OF MACHINERY & MATERIALS, 109 KOREA,KANGWEON NATIONAL UNIVERSITY, 269 KOREA,UNIVERSITY, 69 243 267 KUMOH,NATIONAL UNIVERSITY OF TECHNOLOGY, 64 136 148 199 200 206 269 KWANGJU,INSTITUTE OF SCIENCE & TECHNOLOGY, 245 KYOTO,UNIVERSITY, 89 399 400 KYUNG HEE,UNIVERSITY, 46 KYUNGPOOK,NATIONAL UNIVERSITY, 287 KYUSHU,NATIONAL INDUSTRIAL RESEARCH INSTITUTE, 286 323

L LABORATOIRE DE PHYSICOCHIMIE STRUCT.ET MACROMOL., 250 LAUSANNE,ECOLE POLYTECHNIQUE FEDERALE, 174 LG CHEMICALS LTD., 10 43 LIEGE,CENTER FOR EDUCATION & RESEARCH ON MACROMOLECULES, 62 LIEGE,UNIVERSITY, 31 60 88 102 124 141 152 164 LONDON,IMPERIAL COLLEGE OF SCIENCE,TECHNOL.& MED., 72 LOUGHBOROUGH, UNIVERSITY, 184 209 LULEA,UNIVERSITY OF TECHNOLOGY, 25 65 96 129 147 162 177 179 193 208 237 283 360

M MAHIDOL UNIVERSITY, 320 MARQUETTE,UNIVERSITY, 35 36 70 104 155 169 178 204 214 276 MARYLAND,UNIVERSITY, 151 MASSACHUSETTS, UNIVERSITY, 58 92 116 157 159 196 249 255 332 MCGILL UNIVERSITY, 91 MERS LLC, 61 MICHIGAN,STATE UNIVERSITY, 15 63 173 313 356 364 388 395 403 406 407 MICHIGAN,UNIVERSITY, 172 236 242 262 MILANOBICOCCA,UNIVERSITA DEGLI STUDI, 150 MINAS GERAIS,UNIVERSIDADE FEDERAL, 236 MISSISSIPPI,STATE UNIVERSITY, 183 MISSISSIPPI,STENNIS SPACE CENTER, 183 MONASH,UNIVERSITY, 71 137 139 MONS HAINAUT,UNIVERSITY, 17 31 60 62 88 110 124 141 152 MONS,UNIVERSITY, 102 MONTPELLIER,UNIVERSITY,

© Copyright 2003 Rapra Technology Limited

Company Index

401 MONTREAL,ECOLE POLYTECHNIQUE, 44 MOSCOW,KARPOV INSTITUTE OF PHYSICAL CHEMISTRY, 191 MOSCOW,STATE UNIVERSITY, 354

N NAGOYA,UNIVERSITY, 418 NANCY,UNIVERSITE HENRI POINCARE, 238 NANOCOR, 4 95 NANYA,INSTITUTE OF TECHNOLOGY, 170 NAPLES,INSTITUTE OF COMPOSITE MATERIALS & BIOMATERIALS, 3 NAPOLI,UNIVERSITA FEDERICO II, 3 NASA LANGLEY RESEARCH CENTER, 185 NATIONAL CHIAO TUNG UNIVERSITY, 221 335 NATIONAL RESEARCH COUNCIL OF CANADA, 121 NEW YORK,BARD HALL, 316 NEW YORK,QUEENS COLLEGE, 66 NEW YORK,STATE UNIVERSITY, 66 94 210 217 282 397 NEW YORK,UNION COLLEGE SCHENECTADY, 371 NORTH TEXAS,UNIVERSITY, 98 99 145 201 NORTHERN ARIZONA,UNIVERSITY, 371 NOTTINGHAM,TRENT UNIVERSITY, 86 NOVA CHEMICALS LTD., 344

O OHIO,STATE UNIVERSITY, 78 197 240 OHIO,UNIVERSITY, 144 OREGON UNIVERSITY, 411 OREGON,STATE UNIVERSITY, 239

P PAIS VASCO,UNIVERSIDAD, 223 PALERMO,UNIVERSITY, 40

PENNSYLVANIA,STATE UNIVERSITY, 56 171 176 205 270 299 303 PENNSYLVANIA,UNIVERSITY, 59 PIRELLI CAVI E SISTEMI SPA, 308 PISA,UNIVERSITY, 106 154 367 POLISH ACADEMY OF SCIENCES, 110 POLYMER CHEMISTRY INNOVATIONS INC., 171 POLYMER COMPOSITES, 1 PUNE,NATIONAL CHEMICAL LABORATORY, 6 67 271 PUSAN,NATIONAL UNIVERSITY, 49 83 161

Q QUEBEC,UNIVERSITE LAVAL, 95 QUEENSLAND MANUFACTURING INSTITUTE, 112 QUEENSLAND,UNIVERSITY, 112 113

R RAYTHEON ELECTRONIC SYSTEMS CO., 28 RHODIA RECHERCHES, 238 ROBINSON D.B.,RESEARCH LTD., 344 RUSSIAN ACADEMY OF SCIENCES, 190 354

S SALERNO,UNIVERSITY, 17 106 154 SAO PAULO,UNIVERSITY, 332 SASSARI,UNIVERSITY, 150 SEOUL,NATIONAL UNIVERSITY, 10 168 218 260 292 SHANGHAI,JIAO TONG UNIVERSITY, 19 38 48 247 263 289 337 346 SINGAPORE,INSTITUTE OF MATERIALS RESEARCH & ENGINEERING, 41 SOGANG,UNIVERSITY, 198 SOLUTIA INC., 92 194 SOLVAY ENGINEERING POLYMERS, 98

© Copyright 2003 Rapra Technology Limited

SOUTH CHINA,UNIVERSITY OF TECHNOLOGY, 322 SOUTHERN CALIFORNIA,UNIVERSITY, 146 SOUTHERN CLAY PRODUCTS INC., 76 85 114 228 338 SOUTHERN MISSISSIPPI,UNIVERSITY, 27 29 135 155 229 274 SOUTHWEST TEXAS,STATE UNIVERSITY, 275 ST.LOUIS,MISSOURI BAPTIST COLLEGE, 234 STONY BROOK,STATE UNIVERSITY, 188 SUNG KYUN KWAN UNIVERSITY, 292 SUWON,UNIVERSITY, 298 SWEDEN,INSTITUTE FOR PACKAGING AND DISTRIBUTION, 32 SWEDEN,ROYAL INSTITUTE OF TECHNOLOGY, 32

T TAIWAN,NATIONAL CHENG KUNG UNIVERSITY, 140 TAIWAN,NATIONAL CHIAO TUNG UNIVERSITY, 119 128 131 207 222 248 266 272 279 290 326 342 TAIWAN,NATIONAL CHUNGHSING UNIVERSITY, 160 207 TAIWAN,NATIONAL TSING HUA UNIVERSITY, 2 118 261 TAIWAN,SYNCHROTRON RADIATION RESEARCH CENTRE, 207 222 TANTA,UNIVERSITY, 345 390 TATUNG,UNIVERSITY, 254 TECHNION-ISRAEL INSTITUTE OF TECHNOLOGY, 126 166 TEXAS,UNIVERSITY, 228 310 TEXAS,UNIVERSITY AT AUSTIN, 85 111 211 TIANJIN,UNIVERSITY, 259 330 341 TILAB, 127 TNO-TPD, 347 TOKYO BOSEKI KK, 379 TOKYO,INSTITUTE OF TECHNOLOGY, 305 TORINO,UNIVERSITA, 127 169 182 264 308 TOYOBO CO.LTD., 391 TOYOHASHI,UNIVERSITY, 212

165

Company Index

273 315 TOYOTA CENTRAL R & D LABORATORIES INC., 89 93 158 163 227 295 302 327 372 374 377 385 399 400 404 410 412 413 414 415 416 TOYOTA TECHNOLOGICAL INSTITUTE, 9 50 54 81 89 93 158 165 227 280 286 323 TRITON SYSTEMS INC., 76 79 284 TURIN,UNIVERSITY, 192 TUSKEGEE,UNIVERSITY, 28 39 100

U UKRAINE,NATIONAL ACADEMY OF SCIENCES, 349 ULSAN,UNIVERSITY, 83 UNION CHEMICAL LABORATORIES, 253 UNITIKA LTD., 9 50 54 81 165 301 UNITIKA R & D CENTER, 358 US,AIR FORCE RESEARCH LABORATORY, 188 217 256 285 303 312 321 US,AIR FORCE,WRIGHTPATTERSON BASE, 26 28 117 125 143 144 210 217 277 282 402 US,ARMY, 338 US,ARMY RESEARCH LABORATORY, 12 284 314 US,ARMY SOLDIER &

166

BIOLOGICAL CHEMICAL COMMAND, 76 US,EDWARDS AIR FORCE BASE, 173 US,NASA,GLENN RESEARCH CENTER, 100 US,NATIONAL INST.OF STANDARDS & TECHNOLOGY, 52 84 101 105 169 178 202 203 204 258 276 293 303 US,NAVAL ACADEMY, 105 US,NAVAL RESEARCH LABORATORY, 105 UTAH,UNIVERSITY, 256

V VALLADOLID,UNIVERSIDAD, 4 VANTICO AG, 96 VENEZUELA,UNIVERSIDAD CENTRAL, 367

X XIAMEN,UNIVERSITY, 341

Y YAMAGATA,UNIVERSITY, 183 YEUNGNAM,UNIVERSITY, 64 123 220 YOKOHAMA TIRE CORP., 216 YUAN ZE,UNIVERSITY, 138

Z ZAOZHUANG NORMAL COLLEGE, 322 ZHEJIANG,UNIVERSITY, 279 ZLIN,TOMAS BATA UNIVERSITY, 42

W WASEDA,UNIVERSITY, 353 WESTERN KENTUCKY,UNIVERSITY, 47 WESTERN ONTARIO,UNIVERSITY, 16 WILLIAMSBURG,COLLEGE OF WILLIAM & MARY, 185 WISCONSINMADISON,UNIVERSITY, 14 382 WUHAN,UNIVERSITY OF TECHNOLOGY, 339

© Copyright 2003 Rapra Technology Limited

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