Infrared and Raman Spectroscopy of Polymers

Report 134

Infrared and Raman Spectroscopy of Polymers J.L. Koenig

Volume 12, Number 2, 2001

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 Abstracts 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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Previous Titles Still Available Volume 1

Volume 4

Report 3

Advanced Composites, D.K. Thomas, RAE, Farnborough.

Report 37

Report 4

Liquid Crystal Polymers, M.K. Cox, ICI, Wilton.

Polymers in Aerospace Applications, W.W. Wright, University of Surrey.

Report 5

CAD/CAM in the Polymer Industry, N.W. Sandland and M.J. Sebborn, Cambridge Applied Technology.

Report 39

Polymers in Chemically Resistant Applications, D. Cattell, Cattell Consultancy Services.

Report 8

Engineering Thermoplastics, I.T. Barrie, Consultant.

Report 41

Failure of Plastics, S. Turner, Queen Mary College.

Report 11

Communications Applications of Polymers, R. Spratling, British Telecom.

Report 42

Polycarbonates, R. Pakull, U. Grigo, D. Freitag, Bayer AG.

Report 12

Process Control in the Plastics Industry, R.F. Evans, Engelmann & Buckham Ancillaries.

Report 43

Polymeric Materials from Renewable Resources, J.M. Methven, UMIST.

Report 44

Flammability and Flame Retardants in Plastics, J. Green, FMC Corp.

Volume 2 Report 13

Injection Moulding of Engineering Thermoplastics, A.F. Whelan, London School of Polymer Technology.

Report 45

Composites - Tooling and Component Processing, N.G. Brain, Tooltex.

Report 14

Polymers and Their Uses in the Sports and Leisure Industries, A.L. Cox and R.P. Brown, Rapra Technology Ltd.

Report 46

Quality Today in Polymer Processing, S.H. Coulson, J.A. Cousans, Exxon Chemical International Marketing.

Report 47

Report 15

Polyurethane, Materials, Processing and Applications, G. Woods, Consultant.

Chemical Analysis of Polymers, G. Lawson, Leicester Polytechnic.

Report 16

Polyetheretherketone, D.J. Kemmish, ICI, Wilton.

Report 17

Extrusion, G.M. Gale, Rapra Technology Ltd.

Report 49

Report 18

Agricultural and Horticultural Applications of Polymers, J.C. Garnaud, International Committee for Plastics in Agriculture.

Blends and Alloys of Engineering Thermoplastics, H.T. van de Grampel, General Electric Plastics BV.

Report 50

Report 19

Recycling and Disposal of Plastics Packaging, R.C. Fox, Plas/Tech Ltd.

Automotive Applications of Polymers II, A.N.A. Elliott, Consultant.

Report 51

Report 20

Pultrusion, L. Hollaway, University of Surrey.

Biomedical Applications of Polymers, C.G. Gebelein, Youngstown State University / Florida Atlantic University.

Report 21

Materials Handling in the Polymer Industry, H. Hardy, Chronos Richardson Ltd.

Report 52

Polymer Supported Chemical Reactions, P. Hodge, University of Manchester.

Report 22

Electronics Applications of Polymers, M.T.Goosey, Plessey Research (Caswell) Ltd.

Report 53

Weathering of Polymers, S.M. Halliwell, Building Research Establishment.

Report 23

Offshore Applications of Polymers, J.W.Brockbank, Avon Industrial Polymers Ltd.

Report 54

Health and Safety in the Rubber Industry, A.R. Nutt, Arnold Nutt & Co. and J. Wade.

Report 24

Recent Developments in Materials for Food Packaging, R.A. Roberts, Pira Packaging Division.

Report 55

Computer Modelling of Polymer Processing, E. Andreassen, Å. Larsen and E.L. Hinrichsen, Senter for Industriforskning, Norway.

Volume 3

Report 56

Plastics in High Temperature Applications, J. Maxwell, Consultant.

Report 25

Report 57

Joining of Plastics, K.W. Allen, City University.

Report 58

Physical Testing of Rubber, R.P. Brown, Rapra Technology Ltd.

Report 59

Polyimides - Materials, Processing and Applications, A.J. Kirby, Du Pont (U.K.) Ltd. Physical Testing of Thermoplastics, S.W. Hawley, Rapra Technology Ltd.

Foams and Blowing Agents, J.M. Methven, Cellcom Technology Associates.

Volume 5

Report 26

Polymers and Structural Composites in Civil Engineering, L. Hollaway, University of Surrey.

Report 27

Injection Moulding of Rubber, M.A. Wheelans, Consultant.

Report 28

Adhesives for Structural and Engineering Applications, C. O’Reilly, Loctite (Ireland) Ltd.

Report 60

Report 29

Polymers in Marine Applications, C.F.Britton, Corrosion Monitoring Consultancy.

Volume 6

Report 30

Non-destructive Testing of Polymers, W.N. Reynolds, National NDT Centre, Harwell.

Report 61

Food Contact Polymeric Materials, J.A. Sidwell, Rapra Technology Ltd.

Report 31

Silicone Rubbers, B.R. Trego and H.W.Winnan, Dow Corning Ltd.

Report 62

Coextrusion, D. Djordjevic, Klöckner ER-WE-PA GmbH.

Report 63

Conductive Polymers II, R.H. Friend, University of Cambridge, Cavendish Laboratory.

Report 64

Designing with Plastics, P.R. Lewis, The Open University. Decorating and Coating of Plastics, P.J. Robinson, International Automotive Design.

Report 32

Fluoroelastomers - Properties and Applications, D. Cook and M. Lynn, 3M United Kingdom Plc and 3M Belgium SA.

Report 33

Polyamides, R.S. Williams and T. Daniels, T & N Technology Ltd. and BIP Chemicals Ltd.

Report 65

Report 34

Extrusion of Rubber, J.G.A. Lovegrove, Nova Petrochemicals Inc.

Report 66

Report 35

Polymers in Household Electrical Goods, D.Alvey, Hotpoint Ltd.

Reinforced Thermoplastics - Composition, Processing and Applications, P.G. Kelleher, New Jersey Polymer Extension Center at Stevens Institute of Technology.

Report 67

Report 36

Developments in Additives to Meet Health and Environmental Concerns, M.J. Forrest, Rapra Technology Ltd.

Plastics in Thermal and Acoustic Building Insulation, V.L. Kefford, MRM Engineering Consultancy.

Report 68

Cure Assessment by Physical and Chemical Techniques, B.G. Willoughby, Rapra Technology Ltd.

Report 69

Toxicity of Plastics and Rubber in Fire, P.J. Fardell, Building Research Establishment, Fire Research Station.

Report 70

Acrylonitrile-Butadiene-Styrene Polymers, M.E. Adams, D.J. Buckley, R.E. Colborn, W.P. England and D.N. Schissel, General Electric Corporate Research and Development Center.

Report 71

Rotational Moulding, R.J. Crawford, The Queen’s University of Belfast.

Report 72

Advances in Injection Moulding, C.A. Maier, Econology Ltd.

Report 94

Compressive Behaviour of Composites, C. Soutis, Imperial College of Science, Technology and Medicine.

Report 95

Thermal Analysis of Polymers, M. P. Sepe, Dickten & Masch Manufacturing Co.

Report 96

Polymeric Seals and Sealing Technology, J.A. Hickman, St Clair (Polymers) Ltd.

Volume 9 Report 97

Rubber Compounding Ingredients - Need, Theory and Innovation, Part II: Processing, Bonding, Fire Retardants, C. Hepburn, University of Ulster.

Report 98

Advances in Biodegradable Polymers, G.F. Moore & S.M. Saunders, Rapra Technology Ltd.

Report 99

Recycling of Rubber, H.J. Manuel and W. Dierkes, Vredestein Rubber Recycling B.V.

Volume 7 Report 73

Reactive Processing of Polymers, M.W.R. Brown, P.D. Coates and A.F. Johnson, IRC in Polymer Science and Technology, University of Bradford.

Report 74

Speciality Rubbers, J.A. Brydson.

Report 75

Plastics and the Environment, I. Boustead, Boustead Consulting Ltd.

Report 100 Photoinitiated Polymerisation - Theory and Applications, J.P. Fouassier, Ecole Nationale Supérieure de Chimie, Mulhouse.

Report 76

Polymeric Precursors for Ceramic Materials, R.C.P. Cubbon.

Report 101 Solvent-Free Adhesives, T.E. Rolando, H.B. Fuller Company.

Report 77

Advances in Tyre Mechanics, R.A. Ridha, M. Theves, Goodyear Technical Center.

Report 102 Plastics in Pressure Pipes, T. Stafford, Rapra Technology Ltd.

Report 78

PVC - Compounds, Processing and Applications, J.Leadbitter, J.A. Day, J.L. Ryan, Hydro Polymers Ltd.

Report 103

Report 79

Rubber Compounding Ingredients - Need, Theory and Innovation, Part I: Vulcanising Systems, Antidegradants and Particulate Fillers for General Purpose Rubbers, C. Hepburn, University of Ulster.

Report 80

Anti-Corrosion Polymers: PEEK, PEKK and Other Polyaryls, G. Pritchard, Kingston University.

Report 81

Thermoplastic Elastomers - Properties and Applications, J.A. Brydson.

Report 82

Advances in Blow Moulding Process Optimization, Andres Garcia-Rejon,Industrial Materials Institute, National Research Council Canada.

Report 83

Molecular Weight Characterisation of Synthetic Polymers, S.R. Holding and E. Meehan, Rapra Technology Ltd. and Polymer Laboratories Ltd.

Report 84

Rheology and its Role in Plastics Processing, P. Prentice, The Nottingham Trent University.

Gas Assisted Moulding, T.C. Pearson, Gas Injection Ltd.

Report 104 Plastics Profile Extrusion, R.J. Kent, Tangram Technology Ltd. Report 105 Rubber Extrusion Theory and Development, B.G. Crowther. Report 106 Properties and Applications of Elastomeric Polysulfides, T.C.P. Lee, Oxford Brookes University. Report 107 High Performance Polymer Fibres, P.R. Lewis, The Open University. Report 108 Chemical Characterisation of Polyurethanes, M.J. Forrest, Rapra Technology Ltd.

Volume 10 Report 109 Rubber Injection Moulding - A Practical Guide, J.A. Lindsay. Report 110 Long-Term and Accelerated Ageing Tests on Rubbers, R.P. Brown, M.J. Forrest and G. Soulagnet, Rapra Technology Ltd.

Volume 8

Report 111

Polymer Product Failure, P.R. Lewis, The Open University.

Report 85

Ring Opening Polymerisation, N. Spassky, Université Pierre et Marie Curie.

Report 112 Polystyrene - Synthesis, Production and Applications, J.R. Wünsch, BASF AG.

Report 86

High Performance Engineering Plastics, D.J. Kemmish, Victrex Ltd.

Report 113 Rubber-Modified Thermoplastics, H. Keskkula, University of Texas at Austin.

Report 87

Rubber to Metal Bonding, B.G. Crowther, Rapra Technology Ltd.

Report 114 Developments in Polyacetylene - Nanopolyacetylene, V.M. Kobryanskii, Russian Academy of Sciences.

Report 88

Plasticisers - Selection, Applications and Implications, A.S. Wilson.

Report 115 Metallocene-Catalysed Polymerisation, W. Kaminsky, University of Hamburg.

Report 89

Polymer Membranes - Materials, Structures and Separation Performance, T. deV. Naylor, The Smart Chemical Company.

Report 116 Compounding in Co-rotating Twin-Screw Extruders, Y. Wang, Tunghai University.

Report 90

Rubber Mixing, P.R. Wood.

Report 117 Rapid Prototyping, Tooling and Manufacturing, R.J.M. Hague and P.E. Reeves, Edward Mackenzie Consulting.

Report 91

Recent Developments in Epoxy Resins, I. Hamerton, University of Surrey.

Report 118 Liquid Crystal Polymers - Synthesis, Properties and Applications, D. Coates, CRL Ltd.

Report 92

Continuous Vulcanisation of Elastomer Profiles, A. Hill, Meteor Gummiwerke.

Report 119 Rubbers in Contact with Food, M.J. Forrest and J.A. Sidwell, Rapra Technology Ltd.

Report 93

Advances in Thermoforming, J.L. Throne, Sherwood Technologies Inc.

Report 120 Electronics Applications of Polymers II, M.T. Goosey, Shipley Ronal.

Titles Available in the Current Volume Volume 11 Report 121 Polyamides as Engineering Thermoplastic Materials, I.B. Page, BIP Ltd. Report 122 Flexible Packaging - Adhesives, Coatings and Processes, T.E. Rolando, H.B. Fuller Company. Report 123 Polymer Blends, L.A. Utracki, National Research Council Canada. Report 124 Sorting of Waste Plastics for Recycling, R.D. Pascoe, University of Exeter. Report 125 Structural Studies of Polymers by Solution NMR, H.N. Cheng, Hercules Incorporated. Report 126 Composites for Automotive Applications, C.D. Rudd, University of Nottingham. Report 127 Polymers in Medical Applications, B.J. Lambert and F.-W. Tang, Guidant Corp., and W.J. Rogers, Consultant. Report 128 Solid State NMR of Polymers, P.A. Mirau, Lucent Technologies. Report 129 Failure of Polymer Products Due to Photo-oxidation, D.C. Wright. Report 130 Failure of Polymer Products Due to Chemical Attack, D.C. Wright. Report 131 Failure of Polymer Products Due to Thermo-oxidation, D.C. Wright. Report 132 Stabilisers for Polyolefins, C. Kröhnke and F. Werner, Clariant Huningue SA.

Volume 12 Report 133 Advances in Automation for Plastics Injection Moulding, J. Mallon, Yushin Inc.

Infrared and Raman Spectroscopy of Polymers J. L. Koenig (Case Western Reserve University)

ISBN: 1-85957-284-7

Infrared and Raman Spectroscopy of Polymers

Contents 1.

Introduction .............................................................................................................................................. 5

2.

Elementary Theory of Vibrational Spectroscopy ................................................................................. 5

3.

2.1

Selection Rules for IR Spectroscopy .............................................................................................. 6

2.2

Selection Rules for Raman Spectroscopy ....................................................................................... 6

Basis of Vibrational Spectroscopy as a Structural Tool ....................................................................... 6 3.1

4.

Structural Dependence of Vibrational Frequencies ........................................................................ 6

Vibrational Spectroscopic Instrumentation .......................................................................................... 7 4.1

Types of IR Instrumentation ........................................................................................................... 7 4.1.1 4.1.2 4.1.3 4.1.4 4.1.5 4.1.6

4.2

Types of Raman Instrumentation .................................................................................................... 9 4.2.1 4.2.2 4.2.3 4.2.4 4.2.5 4.2.6

5.

Dispersive IR Instrumentation ............................................................................................ 7 FTIR Instrumentation ......................................................................................................... 7 Microscopic FTIR Instrumentation .................................................................................... 7 FTIR Imaging Instrumentation ........................................................................................... 8 Filter IR Instrumentation .................................................................................................... 8 Fibre-Optic IR Instrumentation .......................................................................................... 9 Dispersive Raman Instrumentation .................................................................................... 9 Fourier Transform Raman Instrumentation ........................................................................ 9 Resonance Raman Instrumentation .................................................................................. 10 Surface-Enhanced Raman Instrumentation ...................................................................... 10 Raman Mapping and Imaging Instrumentation................................................................ 11 Fibre-Optic Raman Instrumentation................................................................................. 11

Sampling for Vibrational Spectroscopy ............................................................................................... 11 5.1

IR Sampling .................................................................................................................................. 11 5.1.1 5.1.2 5.1.3 5.1.4 5.1.5 5.1.6

Transmission Spectroscopy .............................................................................................. 12 Internal Reflection (or Attenuated Total Reflection (ATR)) (a.20) .................................. 12 External Reflection Spectroscopy .................................................................................... 13 Diffuse Reflectance FTIR (DRIFT) Spectroscopy........................................................... 13 Emission Spectroscopy ..................................................................................................... 13 Microsampling .................................................................................................................. 13

5.2 Sampling for Raman Spectroscopy ................................................................................................... 13 5.2.1 6.

7.

Microscopic Sampling in Raman Spectroscopy and Imaging ......................................... 14

Measuring Polymer Orientation with IR and Raman Spectroscopy ............................................... 14 6.1

IR Dichroism ................................................................................................................................. 14

6.2

Raman Characterisation of Polymer Orientation ......................................................................... 15

IR and Raman Applications to Polymer Characterisation ................................................................ 16 7.1

Material Identification .................................................................................................................. 16

1

Infrared and Raman Spectroscopy of Polymers

7.1.1 7.1.2

Additive Analysis ............................................................................................................. 16 Chromatographic Separation and Identification .............................................................. 17

7.2

Determination of the Chemical Structure of a Repeating Unit .................................................... 17

7.3

Crystalline and Conformational Structural Order in Polymers .................................................... 18 7.3.1 7.3.2 7.3.3 7.3.4 7.3.5

Introduction ...................................................................................................................... 18 Crystal Phases of Polymers .............................................................................................. 18 Complex Formation between Polymers and Complexing Agents ................................... 19 Conformational Analysis .................................................................................................. 19 Nematic Ordering in Polymer Dispersed Liquid Crystals ............................................... 19

7.4

Quantitative Analysis .................................................................................................................... 20

7.5

Copolymer Composition and Structure ........................................................................................ 21

7.6

Polymerisation Kinetics and Mechanism in Multicomponent Systems ....................................... 21 7.6.1 7.6.2 7.6.3 7.6.4

Approach .......................................................................................................................... 21 Examples Using IR Fibre Optics ...................................................................................... 21 Examples Using Raman Fibre Optics .............................................................................. 22 Examples Using Rapid Scan FTIR Spectroscopy ............................................................ 22

7.7 Polymer Blends.................................................................................................................................. 23 7.7.1 7.7.2

Utility of Polymer Blends ................................................................................................ 23 Miscible Blends ................................................................................................................ 23 7.7.2.1 Compatibilised Blends ........................................................................................ 23 7.7.2.2 Reactive Blends ................................................................................................... 23

7.8

Conducting Polymers .................................................................................................................... 24

7.9

Emulsion Polymers ....................................................................................................................... 24

7.10 Graft Polymers .............................................................................................................................. 25 7.11 Degradation of Polymers .............................................................................................................. 26 7.11.1 7.11.2 7.11.3 7.11.4 7.11.5

Degradation with Ionising Radiation ............................................................................... 26 Degradation by Photooxidation ........................................................................................ 26 Degradation by Thermal Oxidation Processes ................................................................. 27 Degradation by Chemical Exposure ................................................................................. 27 Analysis of Evolving Gases from Polymers .................................................................... 28

7.12 Orientation of Polymer Chains Due to External Perturbations .................................................... 28 7.12.1 7.12.2 7.12.3 7.12.4 7.12.5 7.12.6 7.12.7

Approach using Vibrational Spectroscopy ....................................................................... 28 Orientation Functions for Mechanical Deformation ........................................................ 29 Strain-Induced Crystallisation .......................................................................................... 29 Deformation-Induced Conformational Changes .............................................................. 30 Relaxation Processes after Drawing ................................................................................. 30 Electric Field Induced Reorientation of Polymers ........................................................... 30 Laser-Induced Orientation ................................................................................................ 30

7.13 Time-Resolved Spectroscopy ....................................................................................................... 30 7.14 Rheooptical FTIR Spectroscopy ................................................................................................... 31 7.15 Two-Dimensional IR (2D-IR) Spectroscopy ................................................................................ 31 7.16 Recycling of Polymers .................................................................................................................. 33

2

Infrared and Raman Spectroscopy of Polymers

7.17 Depth Profiling from Surfaces and Interfaces .............................................................................. 34 7.17.1 Optical Depth Profiling Using ATR-FTIR Spectroscopy................................................. 34 7.17.2 Depth Profiling Using Photoacoustic IR Spectroscopy ................................................... 34 7.17.3 Depth Profiling Using Confocal Raman Microspectroscopy .......................................... 35 7.18 FTIR Microspectroscopy .............................................................................................................. 36 7.19 FTIR Imaging ............................................................................................................................... 37 7.20 Raman Microimaging ................................................................................................................... 38 Additional References ................................................................................................................................... 39 Abbreviations ................................................................................................................................................. 41 References from the Rapra Abstracts Database .............................................................................................. 43 Subject Index ...................................................................................................................................................... 129

The views and opinions expressed by authors in Rapra Review Reports do not necessarily reflect those of Rapra Technology Limited or the editor. The series is published on the basis that no responsibility or liability of any nature shall attach to Rapra Technology Limited arising out of or in connection with any utilisation in any form of any material contained therein.

3

Infrared and Raman Spectroscopy of Polymers

4

Infrared and Raman Spectroscopy of Polymers

1 Introduction Vibrational spectroscopy represents two physically different, yet complementary spectroscopic techniques: infrared (IR) and Raman spectroscopy. Vibrational spectroscopy is advantageous as an analytical tool for polymers, because it provides a wealth of information about complex macromolecules with respect to composition, structure, conformation, and intermolecular interactions utilising simple sampling techniques. Although both spectroscopic methods have been successfully utilised for many years, recent advances in electronics, computer technologies and sampling techniques make Fourier transform IR (FTIR) and laser-excited Raman spectroscopy powerful and versatile analytical tools. These spectroscopic methods utilise a broad range of sampling techniques and do not require prior separation techniques such as solvent extraction and they do not require high vacuum. Low instrument cost, speed and simplicity make them cost effective for polymer analysis. Additionally, the techniques are suitable for quality and process control applications. IR spectroscopy is one of the most powerful spectroscopic tools available for the analysis of polymer systems (a.1). IR spectroscopy is molecularly specific with high sensitivity. It is based on the absorption or attenuation by matter of electromagnetic radiation of a specified motion of chemical bonds. Through quantum physics, nature defines the absorption modes, their locations in the frequency spectrum and the amount of energy absorbed by each molecule. The absorbance at a characteristic frequency is a measure of the concentration of the chemical species being probed in the sample. The Raman effect occurs when a sample is irradiated by monochromatic light, causing a small fraction of the scattered radiation to exhibit shifted frequencies that correspond to the sample’s vibrational transitions. Ground-state molecules produce lines shifted to energies lower than the source, while the slightly weaker lines at higher frequency are due to molecules in excited vibrational states. These lines, the result of the inelastic scattering of light by the sample, are called Stokes and anti-Stokes lines, respectively. Elastic collisions result in Rayleigh scattering and appear as the much more intense, unshifted component of the scattered light. The ratio of the intensities of the Stokes and anti-Stokes lines can be used to determine the temperature of the sample. In normal Raman scattering, a molecule is excited to a virtual state, which corresponds to a quantum level relating to the electron cloud distortion created by the

electric field of the incident light. A virtual state does not correspond to a real eigenstate (vibrational or electronic energy level) of the molecule, but rather is a sum over all eigenstates of the molecule. Raman spectroscopy is now coming of age as a routine analytical method. Advances in Raman technology have meant that robust, user-friendly equipment can be manufactured at a reasonable cost. Key features of the instruments include high stability and optical efficiency, large frequency scan ranges, confocal and spatial resolution, mapping capability, rapid imaging, high resolution, and near IR (NIR) excitation to reduce interfering fluorescence. These advances allow many applications of Raman spectroscopy and Raman microscopic systems to polymer analysis.

2 Elementary Theory of Vibrational Spectroscopy Vibrational spectra including IR and Raman result from the interactions of the vibrational motions of a molecule with electromagnetic radiation (a.2). A simple harmonic oscillator model can describe these vibrational interactions. After separating the electronic contributions, each molecule has an internal vibrational energy, U, which can be expressed in terms of the coordinates and interbond forces between the atoms constituting the molecule. A nonlinear molecule consisting of N atoms has 3N–6 degrees of freedom. Thus, a set of 3N–6 generalised coordinates, Gi, can be found that completely describes the internal motions of this nonlinear molecule. The internal energy of the molecule can be written as: U = U(G1…Gi) where i = 3N–6. It can be shown that the internal energy can be written:

U = Uo + 1 2

∑Q Λ 2 i

ii

i

where Qi are a set of ith normal coordinates and Λii is a diagonal matrix. Thus, we have a system of weakly coupled harmonic oscillators. The first term, Uo, is the internal potential energy of the molecule in the equilibrium state. The second term represents the contribution to the potential energy from the fundamental collective vibrational bands, while the cubic and higher terms are responsible for combination, difference, and overtone bands.

5

Infrared and Raman Spectroscopy of Polymers

The decomposition of coupled harmonic oscillators into a collection of independent oscillators is known as a normal mode expansion and the independent oscillators are called normal modes. Normal modes are defined as modes of vibration where the respective atomic motions of the atoms are in ‘harmony’, i.e., they all reach their maximum and minimum displacements at the same time. These normal modes can be expressed in terms of bond stretches and angle deformation (termed internal coordinates) and can be calculated by using a procedure called normal coordinate analysis.

2.1 Selection Rules for IR Spectroscopy A normal vibrational mode in a molecule may give rise to resonant IR absorption (or emission) of electromagnetic radiation only when the transition is induced by the interaction of the electric vector, E, of the incident beam with the electric dipole moment, μi, of the molecule. That is, the dynamic dipole moment of the ith normal mode, δμi/δqi or μi, is nonzero. The intensity of the transition is proportional to the square of the transition dipole moment, i.e., the matrix element of the electric dipole moment operator between the two quantised vibrational levels involved.

3 Basis of Vibrational Spectroscopy as a Structural Tool Our primary interest is in determining the structure of polymers so we need to understand the molecular basis of vibrational spectroscopy as a structural tool (a.4). The vibrational energy levels can be calculated from first principles by using a technique called normal coordinate analysis (a.5), and as a result some of the factors influencing spectra have been discovered. The vibrational frequencies of a molecule depend on: • Nature of the motion, • Mass of the atoms, • Detailed geometric arrangements, • Nature of the chemical bonding, and • Chemical and physical environment. Vibrational techniques are particularly sensitive to the structure of the macromolecules. A vast literature exists from which group frequencies have been correlated with structural components of the molecules (a.6).

2.2 Selection Rules for Raman Spectroscopy Raman scattering is envisaged as the process of reradiation of scattered light by dipoles induced (P) in the molecules by the incident light and modulated by the vibrations of the molecules (a.3). In normal Raman scattering by molecules in isotropic media, the dipoles are simply those that result from the action of the electric field component, E, of the incident light on the molecules, P = αE where α is the molecular (dipole) polarisability. The molecule will scatter light at the incident frequency. However, the molecule vibrates with its own unique frequencies. If these molecular motions produce changes in the polarisability, α, the molecule will further interact with the light by superimposing its vibrational frequencies on the scattered light at either higher or lower frequencies. Raman scattering stems from the oscillating polarisability within a molecule as a function of vibration and not from the permanent dipole of the molecule. As a result, Raman spectra are less affected by dipole interactions and as a result show sharp, stable lines.

6

3.1 Structural Dependence of Vibrational Frequencies A vibrational spectrum either is ordinarily recorded in wavenumbers (cm -1 ), the number of waves per centimetre. The relationship between ν and the wavelength, λ (μm), is

ν (cm-1) = (104) / λ(μm) which can also be written

ν (cm-1) = 3 x 1010 Hz The wavenumber scale is directly proportional to the energy and the vibrational frequency of the molecule. In wavenumbers

ΔEvib = h cs ν (cm-1) where ΔEvib is the vibrational energy level separation, h is Planck’s constant (6.62 x 10-34 J.S), and cs is the speed of light (3 x 1010 cm/s).

Infrared and Raman Spectroscopy of Polymers

The fundamental IR region arbitrarily extends from 4,000 cm-1 to approximately 300 cm-1. The far-IR region extends from 300 to 10 cm-1, and the observed bands are due to molecular torsional motions as well as lattice and intermolecular modes. The low IR source energy makes this region generally inaccessible except with special instrumentation. The NIR region extends from 14,000 to 4,000 cm -1 (0.7-2.5 μm) and the observed bands consist of overtones and combinations of fundamental mid-IR bands (a.7). The NIR is becoming an important IR method, particularly in quality control.

4 Vibrational Spectroscopic Instrumentation 4.1 Types of IR Instrumentation IR spectroscopic instrumentation is grouped into multiplex (Fourier transform) and nonmultiplex (dispersive) methods. These two categories reflect the means by which the spectra are acquired.

4.1.1 Dispersive IR Instrumentation A dispersive IR instrument (such as a scanning spectrometer) utilises a grating or prism as a wavelength separation device to resolve the IR radiation into individual wavelength components (referred to as spectral resolution elements). A means is provided in the instrument, such as an exit slit, to isolate specific spectral resolution elements for passage to the detector. The IR spectrum is obtained by moving (scanning) the grating over a given wavenumber region after passing through the sample. The intensity of the spectral resolution element is determined by the intensity of the source and the sensitivity of the detector. Scanning IR spectrometers have a rich history of use but they have a number of disadvantages arising primarily from the ‘step-wise’ nature in which the spectra are acquired. The optical dispersion process and the entrance and exit slits limit the amount of energy falling on the detector to a small fraction of the total IR energy. Additionally, moving the grating or prism imposes strict mechanical tolerances on the optical components. With scanning spectrometers it is not easy to increase the signal-to-noise ratio (SNR) by multiple scanning, as it is difficult to reproduce precisely the position of the grating.

4.1.2 FTIR Instrumentation IR absorbance spectra have traditionally been recorded using dispersive instruments but, since 1970, FTIR instruments have been available that are capable of collecting high-quality spectra in a fraction of the time previously required with enhanced SNR and wavenumber accuracy. The key component of these spectrometers is a Michelson interferometer, which operates on the principle of amplitude division of the incoming light. The mechanism is simple. The incoming light is split inside an interferometer, one beam going to an internal fixed mirror and the other to the moving mirror. After reflection, the beams recombine inside the interferometer, undergoing constructive and destructive interference, producing the interferogram. The spectral information is contained in the interferogram. After the data are detected and stored, it is necessary to perform a mathematical transform operation (a Fourier transform) on the data set to convert it into a conventional spectrum. The primary advantage of multiplexing the spectral resolution elements in the IR is the improvement in the SNR. The improvement arises because the detector irradiance for each measurement is increased. Because the detector noise is constant and independent of the source, the SNR is improved because the multiplexing distributes the detector noise over the intensities of many spectral resolution elements. This distribution process lowers the noise in each spectral resolution element more so than if the spectral resolution element is measured individually by step scanning. Mid-IR measurements are typically performed using a linear scan interferometer and appropriate sampling accessory to guide the light to and from the sample of interest.

4.1.3 Microscopic FTIR Instrumentation FTIR microspectroscopy is a microanalytical technique, which interfaces an FTIR spectrometer to an optical microscope. Regions of interest in the sample are spatially isolated using the microscope’s apertures. It enables the IR spectrum of sampling regions down to about 10 μm resolution to be taken. Consequently, FTIR microscopy is ideal for compositional mapping and analysis of heterogeneous samples whose domain sizes are in the tens of micrometre range. FTIR microscopes use x15 and x10 condensor lenses of the non-IR absorbing Cassegrainian type. They are constructed from front surface mirrors and are mounted

7

Infrared and Raman Spectroscopy of Polymers

on-axis so that the path for the visible light is parafocal and colinear with the IR light. The microscope stage is computer controlled with 1 μm steps. The sample is not physically aperatured since the sample is spatially isolated from the microscope aperatures. For IR microscopy, two apertures take up positions such that their images concide in the sample plane (redundant aperturing). The aperatures are a set of crossed knife blades in the form of a rectangle which is of adjustable size. The principal problem in IR microscopy is the presence of scattered light due to diffraction which limits the spatial resolution by increasing the noise. Diffraction is significant when the aperture dimensions approach the wavelength of the IR radiation. The main effect of diffraction is that at small aperature sizes, light spreads outside the specified area into the surrounding region. As higher spatial resolution is sought, the problem increases, as the apertures are smaller, ultimately leading to loss of spectral quality and photometric accuracy.

4.1.4 FTIR Imaging Instrumentation FTIR imaging (as opposed to FTIR mapping) is a method using two-dimensional array detectors and the image is obtained in the ‘snap-shot’ mode, i.e., all elements of the field of view of the microscope are recorded simultaneously. FTIR imaging is an outstanding new tool for online materials monitoring. A spectroscopic imaging system consists of three components: image capturing, image processing, and a visualisation system. The spectral data obtained from IR imaging are analysed to produce a variety of response factors which are spatially expressed in terms of the individual data grid coordinates. The data collection associated with the spectroscopic mapping contains all of the information required to deconvolute the contributions of the different species in the sample. Using a computer, one can analyse the entire spectral range at each positional coordinate or, for a given frequency, develop a spatial image demonstrating the spatial distribution of an object-specific spectral feature (a.8).

Figure 1 Diagram of an FPA camera imaging system (x and y refer to axis)

• High selectivity (IR spectra are fingerprints of molecules with many bands available), • Rapid acquisition of data, • Sample preparation is simple (optical microscopic methods are generally useful), • Experiment can be automated to trigger acquisition as required and • Images can be computer-enhanced for visualisation and interpretation. FTIR imaging with a focal plane array (FPA) detector is a new state-of-the-art multichannel (a.9) method of simultaneously recording the spectral image of a sample as shown in Figure 1 (a.10). The IR chemical imaging system measures chemicallyspecific IR spectra using a mercury cadmium telluride (HgCdTe) FPA detector which provides broad frequency response (out to ~ 18 μm), high sensitivity (2 x 1011 cm Hz 1/2/Watt), and an operating temperature of 40-60 K.

The advantages of FTIR imaging are: • Micro-spatial (~7 μm) chemical mapping of heterogeneous complex samples, • High sensitivity (ppm in many cases),

8

4.1.5 Filter IR Instrumentation One IR spectroscopic system often used for industrial monitoring is the ‘selective-wavelength’ spectrometer

Infrared and Raman Spectroscopy of Polymers

or a ‘filtometer’ (a contraction of the terms ‘filter’ and ‘photometer’). These devices consist of a source of radiation, energy collecting optics, a beam chopper, a sample compartment, another set of collection optics and a radiation detector or detectors. Interference filters provide wavelength selection.

became a revitalised field. This was followed by the availability of computers, two-dimensional detectors and filter devices to replace monochromaters. Only a few brief remarks will be made here with references given for the interested reader.

The basic function of band-pass optical filters is to efficiently transmit light within a chosen wavelength band and effectively reject the wavelengths lying outside of this band. The ratio of the in-band (desired) transmitted energy to the out-of-band (undesired) transmitted energy is the single most important parameter to be considered.

4.2.1 Dispersive Raman Instrumentation

The electronics of the filtometer include power supplies that operate the source, control temperature and power amplifiers and related circuits that convert detector signals to concentration values. The limitation of this type of control instrumentation is primarily sensitivity particularly when remote sensing, via emission, is the sampling method. Filter IR instruments have found broad applications in process control in the past (a.11). By utilising a portable IR spectrometer, the characteristic chemical sensitivity and selectivity of IR measurements can be performed in the field to interrogate the composition of industrial samples (a.12).

The configuration for a Raman dispersive experiment basically consists of five parts (laser, sample, dispersing element, detector and computer) (a.13). A monochromatic laser beam (excitation radiation) is focused on the scattering sample. The scattered light from the sample is focused on the entrance slit of a monochromator and dispersed. The dispersion element discriminates between the strong elastic scattering (Rayleigh scattering) and the weak inelastically scattered light (Raman scattering) with different frequencies. A typical single monochromator provides stray light rejections of 10-5-10-6 (as a fraction of the Rayleigh light that enters the spectrometer) limited by the imperfections on the optical surfaces such as gratings. Double and triple monochromators are often required to obtain adequate stray light rejection. The Raman spectrum is given by the detection of the intensity of the scattered, frequency-shifted light by a photoelectric system. The resulting signal of the detector is amplified and converted to a form appropriate for plotting as a function of frequency.

4.1.6 Fibre-Optic IR Instrumentation IR-transmitting optical fibres are evanescent wave sensors using a mathematical deconvolution technique to extract the absorbances and follow the concentrations of the components as they occur in both laboratory scale and process production. The fibre-optic probe used can be placed at specific locations within the samples or at the surface. The specificity of the technique, the speed of data acquisition and the portability of equipment make this method ideal as a tool to fundamentally probe polymer reactions and processes. Chalcogenide optical fibres are used to direct IR radiation from an FTIR spectrometer through an attenuated total reflection (ATR) probe immersed in a reactor and back to the spectrometer.

4.2 Types of Raman Instrumentation The evolution of Raman instrumentation has been dramatic. After making difficult measurements with uncertain sources, the laser came along and Raman

4.2.2 Fourier Transform Raman Instrumentation The basic problem in Raman spectroscopy is the inefficiency of the Raman scattering; roughly only one out of 108 incident photons is Raman scattered. This, coupled with the fact that most polymeric systems give rise to an interfering fluorescent background, leads to a real problem of detectibility. For example, if a system contains one part per million of an interfering system which fluoresces under visible excitation, the same incident flux of 10 8 photons will produce 100 fluorescent photons which will completely mask the Raman signal. This fluorescence does not occur when the excitation frequency is below the electronic energy levels of the molecules. The recent development of Fourier transform Raman (FT-Raman) spectroscopy, using NIR excitation, drastically reduces the problem of fluorescent interference. FT-Raman also benefits from advantages inherent to interferometry: high collection efficiency, excellent

9

Infrared and Raman Spectroscopy of Polymers

wavelength precision, easily variable resolution and spectral coverage, software developments in FTIR (a.14). The restrictions of FT-Raman arise from the low SNR. The SNR is limited by detector noise rather than signal shot noise. Detectors in the 1 to 2 μm region are noisy. The result is an SNR comparable to that for a single-channel dispersive system with equal measurement time (a.15).

Ultraviolet Raman resonance (UVRR) spectroscopy provides for chemical species identification from both the characteristic vibrational structure and electronic spectra. The resonance enhancement also increases the absolute sensitivity of detection, making it easier to detect the structures. The advantages of UVRR spectroscopy are high sensitivity, lack of fluorescence and suitability for use in aqueous solutions.

FT-Raman spectroscopy became possible due to the commercial availability of the Nd:YAG laser output at 9395 cm-1. The Stokes-shifted Raman scattering occurs in the 5000-9000 cm-1 spectral range, coincident with the NIR region. Although the photon energy at 1076 nm is insufficient to cause fluorescence (which can overwhelm the weak Raman scattering spectrum), the intensity of Raman scattering is diminished by a factor of ~22, in comparison to excitation at 488.0 nm (the laser frequency of the Ar+ laser); this factor can be compensated for by increasing the excitation power.

Resonance Raman spectroscopy combines both vibrational and electronic spectroscopies. The vibrational spectrum at a particular excitation wavelength provides the first dimension. The excitation spectrum, the intensity of each vibrational band as a function of the excitation wavelength, provides the second dimension. Since most molecules have resonance enhancement in the UV, this approach is quite general, but not universal. The availability of a range of excitation frequencies from the laser source makes exploitation of this form of Raman scattering possible.

To obtain good Raman spectra using the FT-Raman method, the unwanted Rayleigh scattering must be removed. Because of the nature of the Michelson interferometer, both Rayleigh and Raman-scattered light enter the system. Since the Rayleigh component is from 106 to 108 times more intense than the Raman scattering, it must be removed before it reaches the detector, because a signal of this intensity drives the detector into the distributive noise regime, resulting in high-frequency noise spread throughout the transformed spectrum.

4.2.3 Resonance Raman Instrumentation Resonance Raman spectroscopy occurs when the energy of the exciting beam is close to an electronic energy level of the molecule and the excitation makes one term in the sum of eigenstates dominate over all others. Resonance Raman spectroscopy takes place when the frequency of the exciting line is similar to the absorption frequency of a chromophore in the sample. When this occurs, the electron cloud surrounding the molecule is more readily distorted by the electric field of the incident light. The transition has a higher probability, and there is an enhancement of the Raman process. The Raman signal from the chromophore can be enhanced by seven or eight orders of magnitude. The vibrational modes enhanced are dominated by vibrational bands that are part of the chromophore responsible for the resonance. The resonance lines are generally totally symmetric and distort the molecule along directions of electron density changes between the ground and the resonant electronic excited state.

10

Detection of UVRR spectra is complicated by a number of experimental difficulties: the photooxidation and photodestruction of molecules, distortion of spectral information due to optical saturation phenomena and photoinduced transients, and fluctuations of the scattered light intensity in inhomogeneous samples.

4.2.4 Surface-Enhanced Raman Instrumentation In surface-enhanced Raman spectroscopy (SERS), increased Raman signals are observed from molecules attached to metallic clusters ranging in size of the order of tens of nanometres (a.16). Enhancements as high as 1014 have been observed. These enhancement factors can lead to single-molecule Raman spectroscopy (a.17). Using a Raman microscope the probe volume can be as small as 10 picolitres. Spectra can be measured with a one-second collection time. In order to achieve large surface Raman signals, it is necessary that the metal surfaces are specially prepared in one of several ways, which renders them rough or finely divided on a length scale comparable to optical wavelengths. Under favourable conditions, SERSactive metals enhance the surface Raman intensity by up to 105-fold, giving strong Raman signals. The enhancement of Raman scattering at noble metal (gold, platinum, etc.) surfaces can be attributed to two factors. One is an electromagnetic effect (discussed above) observed for molecules near roughened noble metal surfaces, and the second is a chemical interaction

Infrared and Raman Spectroscopy of Polymers

between the absorbed molecule and the metal surface. The electromagnetic enhancement observed by SERS arises from the unique optical properties of noble metals. The zero oxidation electronic configurations of these metals are d10s1. The single s electron is well shielded by the inner shell electrons and behaves as a free electron. In the visible region of the spectrum, this free electron causes the dielectric constant of the metal to have a large negative real component and a small imaginary component. The large negative component of the real part means that the electrons react very strongly to incident radiation and their displacement is such that the field due to the polarisation of the particles resists further polarisation. The result is a resonance condition that absorbs energy from the incident light and creates a locally intense electric field within the metal particle. When the incident radiation interacts with the surface, it causes the free electrons to oscillate with the incident electric field and polarises the noble metal particles. This creates a strong local electric field at the particle surface known as a surface plasmon. When a molecule is in close proximity to a noble metal particle the molecule is polarised by the electric field of the noble metal particle. This leads to an enhancement of the Raman signal because the Raman scattering is proportional to the square of the local electric field.

4.2.5 Raman Mapping and Imaging Instrumentation The ideal Raman spectrometer would consist of a highdispersion, low-stray-light (where the scattered light is low) single monochromator with a multichannel detector. In the new generation of Raman instruments, a polychromator or spectrograph and a multichannel detector are used instead of the monochromator and photomultiplier. The entire spectrum is collected simultaneously using an array of detectors in which each element of the multichannel detector is comparable in sensitivity to a single photomultiplier. The assumption is that all light incident on the detector is correctly positioned with a single wavelength incident upon each single detector. In this way, the time needed to record a spectrum is reduced markedly. Additionally, the simultaneous detection of the spectrum increases the accuracy of intensity measurements of different Raman bands and avoids errors in interpreting accidental changes in the background due to laser fluctuations as Raman bands. Furthermore, multichannel detectors offer new possibilities for investigation of photolabile systems (i.e., systems that degrade by photoirradiation), timeresolved experiments and chemical images.

The wavelength at a particular detector element is determined by the position of that element at the focal plane of the monochromator (the grating position). In another mode of operation, an acousto-optic tunable filter (AOTF) is used rather than a monochromater. In Raman applications, the AOTF is used to spectrally filter the source (a.18). Under computer control, the AOTF is swept through a wavelength range and, at predetermined intervals, images are recorded. For more rapid operation, the AOTF may be digitally tuned to predetermined frequencies where single frames may be collected (a.19). In practice, the AOTF is placed between the Raman scatterer and a Si FPA detector yielding a no-moving parts Raman spectroscopic imager. The AOTF replaces the dispersive monochromator and is operable between 400 nm and 1900 nm. At each discrete wavelength a charge collection detector (CCD) frame is collected, digitised and stored. The size, wavelength range, wavelength increment and exposure time for each image frame maybe modified under computer control. Potentially, one can record one frame/second.

4.2.6 Fibre-Optic Raman Instrumentation A dual-fibre optical probe has been developed for Raman spectroscopic monitoring of a number of polymer processes. In the dual-fibre configuration the internal bundles transmit the light to the sample and the outer fibres carry the signals back to the spectrometer for processing.

5 Sampling for Vibrational Spectroscopy 5.1 IR Sampling One of the most attractive aspects of FTIR spectroscopy is its ability to deal with a great number of sampling techniques, making it a versatile method which can be adapted to the study of a wide range of materials. For IR spectroscopy, sample preparation has been a labour-intensive operation requiring some measure of skill and experience. Conventional IR spectroscopy is mainly based on transmission measurements except for samples for which the preparation of a thin layer is problematic, inadequate, or prohibited. In these cases special sample preparation is required as indicated in Section 5.1.1, 5.1.2, etc. The main sampling techniques may be seen schematically in Figure 2.

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Infrared and Raman Spectroscopy of Polymers

Figure 2 IR sampling techniques for polymers

5.1.1 Transmission Spectroscopy Transmission spectroscopy is the simplest and most popular mode for quantitative analysis. Radiation passes through the sample and is absorbed by a length equal to the thickness of the sample in the direction of IR propagation. The single beam intensity can be ratioed against a background collected without the sample and an absorbance spectrum obtained. The absorbance has a simple linear relation to the concentration under most conditions and can be used for quantitative analysis. In general, it delivers the highest SNR of all sampling techniques and does not affect the spectral data in any manner. No special sample handling techniques are required and quantitative data processing is straightforward. However, films usually have to be thin, i.e., 1 to 100 μm. Such films can be prepared by solvent casting or compression moulding.

5.1.2 Internal Reflection (or Attenuated Total Reflection (ATR)) (a.20) Attenuated reflection may be used for samples with no or low transmission or when sample geometry demands

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it. The sample is brought into contact with an IRtransparent crystal of high refractive index. The IR beam then traverses the length of the crystal while penetrating the sample with multiple internal reflections at the free crystal surface. Thus, depending on the refractive index and angle of incidence, the region of the sample examined is typically a 0.1-10 μm layer close to the crystal. Spectral data is different from that obtained in transmission and the signal does not vary linearly with concentration. Hence, calibration is required for quantitative studies. Depth profiling is also a possibility using the ATR technique (a.21) and probed depth (i.e., how deep in the sample the light probes) varies as dp =

λ

2 π( n sin 2 θ − n 2 ) 2 o

1/ 2

(1)

where dp is the probed depth, no and n are the refractive indices of the ATR crystal and the sample respectively, θ is the angle of incidence and λ the wavelength of radiation. Algorithms to extract depth of penetration independent of wavenumber have been developed (a.22, a.23).

Infrared and Raman Spectroscopy of Polymers

5.1.3 External Reflection Spectroscopy

5.1.6 Microsampling

Reflection-absorption spectroscopy is an external reflection technique that utilises an IR beam incident at a grazing angle. This allows for a convenient method to study polymers in contact with reflective (e.g., metal) surfaces. When IR light impinges on a metal surface, an electrical field arises near the surface. The metallic surface imposes a strict dipole moment selection rule, which demands that the incident light should have a component parallel to the plane of incidence (p- or parallel polarisation). The interaction between the sample and the incident light is strong when the angle of incidence is between 75° and 89° and approaches a maximum at 88°. For parallel-polarised incident radiation, only the dipole moments of the surface species normal substrate interact with the electric field. A detailed discussion of the technique has been published (a.24, a.25). It has been established that the sensitivity of reflection absorption IR spectroscopy is greatly improved when using a grazing incidence (65° or more). In the particular case of thin layers (of organic or inorganic material) deposited on a good reflecting surface such as a metal, a lower detection limit of a few nanometres in thickness can be achieved. The drawbacks include the appearance of asymmetric absorption modes and shifting of mode frequencies that may be corrected by the use of the Kramers-Kronig transformation.

As far as microspectroscopy is concerned, only transmission and reflection under near-normal incidence are initially implemented. The recent launch of specialised objectives provide the user with additional techniques such as external reflection under grazing angle and ATR.

5.2 Sampling for Raman Spectroscopy The sampling techniques used in Raman spectroscopy are shown in Figure 3. A sample in any state can be examined without difficulty by using Raman spectroscopy. The laser beam is narrow, collimated, and unidirectional, so it can be manipulated in a variety of ways depending on the configuration of the sample.

5.1.4 Diffuse Reflectance FTIR (DRIFT) Spectroscopy Light impinging on a solid or powdered surface is diffusively scattered in all directions and may be directed to an IR detector. This technique is particularly useful if the sample is strongly scattering and weakly absorbing. A general theory for powdered samples was developed by Kubelka and Munk (a.26) and relates the sample concentration to the scattered radiation intensity. DRIFT spectroscopy requires little sample preparation, is ideal for particulate substances and has fast data collection with good SNR. However, some information is lost in the highly absorbing regions and there is small band shape distortion. Quantitative analysis should be performed on the same particle size. DRIFT spectroscopy has been used to probe polymer layers, fibres and polymers on metals (a.27).

5.1.5 Emission Spectroscopy If collected correctly, emission spectra mirror absorbance spectra and can be collected even from opaque samples. The material must not have thermal gradients, readsorption of emission, or self-adsorption.

Figure 3 Raman sampling techniques for polymers

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Infrared and Raman Spectroscopy of Polymers

For liquids, a cylindrical cell of glass or quartz with an optically flat bottom is positioned vertically in the laser beam. For solids, the particular method used depends on the transparency of the sample. For clear pellets or samples, right angle scattering is used. With translucent samples, it is helpful to drill a hole in the sample pellet. Powdered samples can be analysed by using front-surface reflection from a sample holder consisting of a hole in the surface of a metal block inclined at 60° with respect to the beam. Injection moulded pieces, pipes, and tubing, blown films, cast sheets, and monofilaments can be examined directly. One of the advantages of Raman sampling is that glass containers can be used which can be sealed if desired (a.29).

5.2.1 Microscopic Sampling in Raman Spectroscopy and Imaging The incorporation of high-resolution optics in a Raman spectrometer allows sampling from areas of less than 1 x 10-6 m in diameter. The addition of a confocal microscope improves the axial resolution to a couple of microns. Those developments, along with the introduction of notch filters and holographic transmission gratings, allow the reduction of the acquisition time of Raman spectra from minutes to seconds. The fast data collection combined with the high lateral and vertical resolutions makes possible the collection of Raman images with several micron spatial resolutions.

6 Measuring Polymer Orientation with IR and Raman Spectroscopy

direction of alignment is required in order to understand how molecular design and processing strategies lead to the ultimate state of alignment. There are several methods available, including IR dichroism, X-ray diffraction, nuclear magnetic resonance (NMR), birefringence, polarised fluorescence, ultrasonic measurements, and polarised vibrational spectroscopies (IR and Raman). Of all these techniques, IR dichroism is one of the most frequently applied, since it is applicable to many polymer systems, it can be used to make measurements on the microscopic and macroscopic scales, and it can specifically measure orientation of different phases (i.e., amorphous or crystalline) in the same sample.

6.1 IR Dichroism In general, IR absorption is caused by the interaction between the IR electric field vector and the molecular dipole transition moments related to the molecular vibrations. Absorption is at a maximum when the electric field vector and the dipole transition moment are parallel to each other. In the case of perpendicular orientation, the absorption is zero. Directional absorptions are measured using polarised light. The terms parallel and perpendicular refer to the orientation of the polarised beam with respect to a reference axis. For deformation studies, the reference axis corresponds to the stretching direction. The IR dichroic ratio may be considered to be characteristic of the directional orientation of the segments of the molecule. For a polymer whose molecular axis is oriented parallel to the spectrometer sampling plane, the dichroic ratio, R, is defined as R=

Orientation can be defined as the preferential alignment (either uniaxial or biaxial) of polymer chains or segments when submitted to an external force. The orientation induces significant changes in the properties both positively and negatively. A high degree of alignment is the basis of improved mechanical, optical, and electrical properties in almost all polymers. Many factors influence the orientation behaviour of polymer chains, including crystallinity, phase separation, free volume, chain rigidity, molecular friction, interchain interactions and chain entanglements. Consequently, it is necessary to understand the correlations among molecular order, material properties, and fabrication procedures. Experimental characterisation of the degree and

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A || A⊥

where A|| is the absorbance parallel to the chain axis, and A⊥ is absorbance perpendicular to the chain axis. For highly oriented samples, the dichroic ratio may approach either infinity or zero, depending on the alignment of the transition-moment vector with respect to the molecular chain axis. The alignment of the chain segments can be determined from dichroic ratio measurements if the inherent polarisations are known (a.29). In general, A|| and A⊥ are determined successively by using a polariser that is aligned parallel and perpendicular to the stretching direction. For samples that have a low level of orientation, the magnitude of the dichroic ratio is close to 1. In these cases of minimal

Infrared and Raman Spectroscopy of Polymers

orientation, it is better to measure the dichroic difference A || –A ⊥ because it is a more sensitive measurement under these conditions. One of the practical problems in the case of IR dichroism measurements arises from the requirement of low band absorbance (roughly lower than 0.7 absorbance units) in order to permit use of the BeerLambert law. This condition implies use of very thin films in the range of 1 to 200 μm. NIR measurements alleviate this problem.

6.2 Raman Characterisation of Polymer Orientation Raman scattering arises from the interaction between radiation induced oscillating electric dipoles and molecular vibrational modes. In general, the induced polarisability is not necessarily in the direction of the incident beam, and they are related by a second range tensor, α, thus: P = αE or written in terms of the components: Px = αxxEx + αxyEy + αxzEz Py = αyxEx + αyyEy + αyzEz Pz = αzxEx + αzyEy + αzzEz where αxx, αyy and αzz are the components of the principal axes of the polarisability ellipsoid and αxy, αyz and αxz are the other components. A single crystal can give up to six different spectra, depending on its orientation towards the two directions of polarisation of the incident laser light. Consequently, the Raman scattered light emanating from even a random sample is polarised to a greater or lesser extent. For randomly oriented systems, the polarisation properties are determined by the two tensor invariants of the polarisation tensor, i.e., the trace and the anisotropy. The depolarisation ratio is always less than or equal to 3/4. For a specific scattering geometry, this polarisation is dependent upon the symmetry of the molecular vibration giving rise to the line. In solids, the problem of polarisation is more complicated, but the results are more rewarding (a.30). In solids, the molecular species are oriented with respect to each other. Therefore, the molecular

polarisability ellipsoids are also oriented along definite directions in the solid. Since the electric vector of the incident laser beam is polarised, the directionality in the crystal can be utilised to excite and obtain Raman data from each element of the polarisability ellipsoid. With the laser polarisation along z and collection along z, a spectrum from the αzz component of the tensor is obtained. By rotating the analyser 90°, thereby collecting x polarised light while still exciting along z, αzx is obtained. In the usual Raman experiment, the observations are made perpendicular to the direction of the incident beam, which is plane polarised. The ‘depolarisation ratio’ is defined as the intensity ratio of the two polarised components of the scattered light which are parallel and perpendicular to the direction of the propagation of the (polarised) incident light. The polarisation of the incident beam is perpendicular to the plane of propagation and observation. For this geometry, the depolarisation ratio is defined as the intensity ratio: ρ = VH/VV where, for the right angle scattering experiment, V is perpendicular to the scattering plane and H is in the scattering plane. An alternate notation expressed in terms of the laboratory coordinate system is: A(BC)D where A is the direction of travel of the incident beam, B and C are the polarisation of the incident and scattered light, respectively, and D is the direction in which the Raman scattered light is observed. Generally, the incoming beam is along the x axis, the scattered beam is along the z axis and the y axis is perpendicular to the scattering plane. One of the major problems is the difficulty of determining that the polarisation is scrambled whether by scattering inhomogeneities in the sample itself or by the birefringence of the sample itself. Many spectra show evidence of extensive depolarisation of both the incident and scattered light, and thus each spectrum is an indeterminate mixture of four different polarisations: the intended polarisation, the one resulting from depolarisation of the incident light, the one resulting from depolarisation of the scattered light, and (to a lesser extent) the one resulting from depolarisation of both the incident and scattered light. When this occurs, little useful information is available from the individual polarised spectra.

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Infrared and Raman Spectroscopy of Polymers

7 IR and Raman Applications to Polymer Characterisation 7.1 Material Identification IR and Raman spectroscopy are the best methods for the identification of unknown compounds if the spectra of the reference compounds are known. The idea underlying spectroscopic identification is that a pattern of frequencies provides a ‘fingerprint’ of a particular molecule and that this pattern of frequencies can be recognised when a spectral database is searched. Spectral comparison of an unknown sample for identification is generally done by visual comparison (often with the computer as a tool) or by using crosscorrelation techniques. With cross-correlation techniques, an identification is performed by calculating a matching score for the spectra of the unknown and an IR spectrum of a known compound in the database. Additional spectra in the database are ranked according to the matching score determined and the spectroscopist must make a final determination based on his knowledge of the properties of the unknown sample relative to the chemicals with high matching scores.

polymer and additives are also available (166, 357) including one for fibres (376). For Raman identification, the databases are smaller because of the limited history of collection of spectra but attempts are being made to bridge the gap (a.31).

7.1.1 Additive Analysis Polymer additives are materials designed to enhance or upgrade the performance or capabilities of base polymers to achieve the optimal properties for a specific application (a.32). Plastics would not be able to perform their diverse functions without the assistance of a very broad range of plastics additives (a.33). Without them, some plastics would degrade during processing and, over time, the polymers would lose impact strength, discolour, and become statically charged, to list just a few problems. Additives not only overcome these and other limitations, but can also impart improved performance properties to the final product.

Independent of the type of scoring system used, there is always a risk of obtaining a false identification result. Each measured spectra can match the frequencies of several different molecules in addition to the match with the molecule actually present in the sample. False results are caused by the accidental matching of the frequencies of a chemical with no properties similar to the unknown. An incorrect result is also obtained when the score due to random matching cannot be discerned from the score match due to matching of the real spectra in the sample. It is therefore useful to include other information when interpreting the quality of the match, such as the chemistry involved in the unknown sample. The likelihood of accidental matches (and hence the likelihood of false identification) increases if the spectral reproducibility is reduced.

It is necessary to be able to identify and quantify the additives in polymers and vibrational spectroscopy is a particularly useful approach to this problem. Compared with traditional chemical analyses, vibrational methods are nondestructive and are timeand cost-effective as well as more precise. A large number of examples exist in the literature. For example, antistatic agents (polyethylene glycol (PEG) in polyethylene (PE)) can be detected directly using FTIR sampling (367). An IR spectroscopic technique for the analysis of stabilisers (2, 6-di-tert-butyl-4methylphenol) in PE and ethylene-vinyl acetate (EVA) copolymer has been described (368). It is possible to quantify the amount of external and internal lubricants (stearic acid in polystyrene (PS)) (371). Fillers in polymers can also be analysed (white rice husk ash (predominantly silica in polypropylene (PP)) (268). Raman spectroscopy has been used to detect residual monomer in solid polymethyl methacrylate (PMMA) samples (326).

The Sadtler division of Bio-Rad Laboratories (http:// www.sadtler.com) has a product on compact disc containing 175,000 IR and 3,300 Raman spectra. For a subscription price the user gets the disc and an emailed code from Sadtler that opens the disc for searches on one computer for a year. Once the code opens the disc, the user may perform unlimited lookups on one computer for one year. A lookup retrieves spectra by names or structures for comparison. In addition, the user may perform unlimited searches to identify or classify unknowns. Other databases for

It is also possible to determine multiadditives in the same sample using FTIR and multivariate analysis methods. For example, the simultaneous determination of the concentrations of silica, erucamide and butylhydroxytoluene in PE were measured using IR spectroscopy and suitable calibration models. The concentrations were between 20 and 1100 wt/ppm (366). A multiadditive method was developed for characterisation of an antiblocking agent (silica) and lubricant (erucamide) in molten low density polyethylene (LDPE) samples (324).

16

Infrared and Raman Spectroscopy of Polymers

A method for the determination of vulcanised rubber additives by FTIR spectroscopy using partial leastsquares regression (PLSR) for multivariate calibration was developed (264). Interestingly enough, photoacoustic FTIR spectroscopy was used to characterise tread lugs sectioned from two worn offthe-road tyres. The tyres had experienced similar service but displayed significantly different performance in that ‘chipping/chunking’ was visible in one tyre brand. The technique was also used to examine a variety of rubber compounding ingredients, such as polymers and fillers, and model tyre compounds containing different levels of these ingredients (341). A long standing problem in analysing natural rubber (NR) is the determination of attached nitrogenous compounds. Bands at 3280 and 1540 cm-1 diminished when a fresh field latex was treated with enzyme followed by washing in the presence of surfactant. A band at 3320 cm-1 that remained after the treatment indicated the presence of residual amino acids bonded to the hevea rubber particles (349). A surface method of measurement of a sizing agent (partly hydrolysed polyvinyl alcohol) on the warp yarn substrate (polyester/cotton) using NIR diffuse reflectance spectroscopy has been described (337). A partial least-squares (PLS) modelling procedure used a frequency segment of the NIR spectrum that is most sensitive to changes in size concentration relative to the warp yarn.

7.1.2 Chromatographic Separation and Identification The combination of chromatography and IR spectroscopy provides a versatile tool for the characterisation of additives. High performance liquid chromatography-FTIR (HPLC-FTIR) interface systems deposit the output of a chromatograph on an IR optical medium, which is then scanned to provide data as a time-ordered set of spectra of the chromatogram (138). A spray-jet interface is used to deposit the effluent from a narrow-bore liquid chromatography (LC) column on a zinc selenide window. The deposited additives are analysed by FTIR transmission microscopy, yielding identification limits in the low-nanogram range (215). Although it is not a real time analysis, it has the advantages of total solvent removal before IR analysis, analysis of the total LC effluent as opposed to incremental fractions, and the ability to produce IR spectra at high SNR. A powerful new method of additive extraction has been developed termed supercritical fluid extraction/FTIR

spectroscopy (SFE/FTIR) (303). The SFE/FTIR technique has been applied to the analysis of fibre finishes on fibre/textile matrices. Three different fibre polymer types were examined (polyurethane (PU), polyamide (PA) and aramid), each requiring a different finish. Finishes ranged from a single-component polydimethylsiloxane (PDMS) oil to more complex multicomponent finishes that included various surfactants, fatty acid esters and soaps, antioxidants and oils.

7.2 Determination of the Chemical Structure of a Repeating Unit The most common type of structure determination is structure verification. In this case, enough information is available (perhaps on the basis of well-known synthetic reaction paths) to propose a probable structure. The structure information which is achieved using IR and Raman spectroscopy is usually sufficient here. One of the fundamental problems in polymer science is the determination of the chemical structure of the repeat unit; this moiety determines all of the chemical properties such as reactivity, stability and weatherability. Vibrational spectroscopic techniques are advantageous as a method of determining structure because the methods are applicable to all polymers regardless of the state of order. The IR and Raman spectroscopy methods are accurate, faster than chemical analysis and reduce exposure to irritating, toxic and corrosive chemicals. Bisphenol A phenoxy polymers and bisphenol A polycarbonates were blended in solution. Chemical changes from aromatic to aliphatic carbonate groups were monitored by FTIR as a function of time and temperature (348). The network structure of an epoxy resin system and the course of reaction of bisphenol A diglycidyl ether with 1-cyanoguanidine as curing agent dissolved in dimethyl formamide in the presence of different accelerators were studied. Fractions of reactive groups, such as oxirane rings, primary and secondary hydroxyl groups, imide and nitrile groups, were detected as functions of epoxy consumption and reaction conditions. Structural tautomerism of the curing agent, the influence of water, the reaction of nitrile groups and other structural features of the curing system were examined (354). The compound n-butyllithium was the initiator and cyclohexane the solvent for high-vinyl polybutadienes produced from anionic polymerisation. Complexing

17

Infrared and Raman Spectroscopy of Polymers

agents were used to change the mode of addition to 1,2 or vinyl, 1,2-dipiperidinoethane and diglyme were very effective, although their effectiveness decreased with temperature. The microstructure of the polymers was characterised by Raman spectroscopy using the Raman active carbon-carbon double bond stretching bands of cis and trans vinyl structures at 1640, 1650 and 1664 cm-1, respectively. The amount of each component was measured using band areas (369). An IR method was developed for determining the hydroxyl number in samples of polyesters formed by the copolymerisation of a hydroxy-functional acrylic oligomer with adipic acid and 1, 6-hexanediol (370). Oxazolidone-isocyanurate polymers were prepared by reacting five glycidyl ethers with 4, 4´-diisocyanatodiphenylmethane in the presence of 2-ethyl-4methylimidazole. The degree of cure of the resins was followed by IR spectroscopy by measuring the fraction of the isocyanurate to oxazolidone linkages (377).

7.3 Crystalline and Conformational Structural Order in Polymers 7.3.1 Introduction IR and Raman spectra are particularly sensitive to the configurations and conformations of the polymer molecules. The variations in the conformational and configurational structures are reflected in specific observable frequencies. Consequently, it is possible to detect and quantify the amounts of the conformational isomers whether they be crystalline, liquid crystalline, or disordered (amorphous). The vibrational spectroscopic approach to structural elucidation in polymers relies on the comparison of vibrational spectra of polymers containing specific conformational structures (incorporated into the polymer during polymerisation or by thermal or chemical modification), with spectra of models (polymers and small molecules) containing similar structures presumed to be present in the polymers.

7.3.2 Crystal Phases of Polymers Structural changes in the orthorhombic-to-hexagonal phase transition of PE crystals were investigated in the course of heating to the melting point. The IR and spectral patterns characteristic of the hexagonal phase were confirmed. In particular, the bands characteristic of the disordered short trans segments (shorter than

18

five methylene units) and the bands of the kink or double gauche linkages were detected. The observation of the trans and gauche bands was confirmed as well as the existence of conformationally disordered chains in the hexagonal phase (195). The defect density of states of the tight (110) fold in PE is calculated. Modes of the (110) fold calculated at 1348, 1342 and 1288 cm-1 and are assigned to IR bands at 1346-1347 cm-1 and 1342-1343 cm-1 and near 1295 cm-1. The (110) folds (approximately g′g′ggtg) also contribute to the gtg/gtg′ bands at 1368 cm-1, where g = +60° and g′ = -60° from the plane of the C-C backbone and t = trans. In contrast to the (200) fold, the (110) fold does not exhibit a localised gap mode near 700 cm-1. The observed IR bands are assigned to the defect modes of the (110) fold (373). The (110) folds are folds in the crystal plane and (200) folds lie along the (200) crystal plane. The phase transition in an ethylene-tetrafluoroethylene alternating copolymer from the orthorhombic to the hexagonal structure is a result of the generation and propagation of conformational collective defects (182). Syndiotactic poly-p-methylstyrene (PPMS) exhibits various crystalline forms and clathrate structures. Bands due to the syndiotactic stereostructure and bands typical of the two different chain conformations are observed in the crystalline structures as well as bands sensitive to intermolecular interactions typical of the different modes of chain packing (350). In polyamide 66, normalised absorbances of the bands at 924 and 1136 cm-1 were plotted against density and the intercept at zero absorbance provided a density of 1.26 g/cm3, which was very close to the crystalline density. The 924 and 1136 cm-1 bands are assigned to the conformation in the amorphous phase. The assignments of the bands at 936 and 1200 cm -1 to the conformation in the crystalline phase were confirmed (31). FTIR analysis provided a direct method for the evaluation of the amount of alpha and beta form crystalline phases in syndiotactic PS, although both contain chains in the same conformation (trans-planar) (186). Syndiotactic PS was found to exhibit two distinct vibrational peaks in the Raman spectrum. The presence of long all-trans sequences gives rise to a peak at about 773 cm-1, whereas trans/gauche conformations result in a separate peak at 798 cm-1. With increasing levels of crystallinity, the integrated intensity of the 773 cm-1 grows at the expense of the 798 cm-1. The relative area

Infrared and Raman Spectroscopy of Polymers

under the all-trans fundamental band can be directly related to the crystalline volume fraction (173). Cyclohexa(p-phenylene sulfide) (CHPS) is a precursor of poly(p-phenylene sulfide) (PPS). The FTIR and Raman spectra of CHPS resemble those of amorphous PPS. Specific modes indicative of the crystal structure and band shifts are reported and a crystal structure change in CHPS which was induced by pressure or heat is identified (84).

7.3.3 Complex Formation between Polymers and Complexing Agents Interactions between polyvinyl chloride (PVC) and cyclohexanone or n-methyl-2-pyrrolidone generated the occurrence of local configurational changes. The results suggest that the interaction is restricted to a definite number of polymer sites although no information as to the exact type of these sites can be drawn. The number of interaction sites is higher for cyclohexanone than for N-methyl-2-pyrrolidone (181). The IR spectrum of the delta phase of the syndiotactic PS/ethylbenzene complex predominantly involved bands in the 920 to 960 cm-1 region arising from helical structures. The 934 and 943 cm-1 peaks behaved as a doublet, primarily due to the delta phase, with the splitting increasing on annealing. The 940 cm-1 peak was solely due to the gamma phase helix. These assignments provide the opportunity for using these bands for further studies of complexation/ decomplexation in systems of this type (89).

7.3.4 Conformational Analysis A study of annealed polycarbonate showed that the heating process was primarily a modification of trans-trans and trans-cis population of the carbonate group, leading to a more stable structure with a lower internal energy. Ageing proceeded mainly by extremely local rearrangements compatible with a densified structure (177). The IR characteristic bands at 1230/1250 cm-1 of stereoregular polyacrylonitrile (PAN) are dependent on not only the configuration, but also on the conformation through the arrangements of the configurations on the polymer chain. The effect of configuration and conformation on the IR results was determined to be a function of the film preparation conditions (180).

Isotactic PS samples were shock-cooled and subsequently freeze-dried from very dilute solutions in benzene. FTIR studies on these samples indicated that there were conformational differences between these samples and a normal isotactic PS. Comparison of the IR spectra indicated that spectral changes occurred at the bands near 1261, 1085-1050, 982, 923906 and 550 cm-1. The changes in intensity of the crystalline bands showed that the freeze-dried isotactic PS from a very dilute solution exhibited a higher crystallinity than annealed samples (252). The conformational structures of polycarbonate were studied in the solid state and in solution. Based on the temperature dependences of the IR spectra, bands sensitive to transitions between the trans-trans and trans-cis conformations of the carbonate group were identified (361). The conformers of the ethylene glycoxy moeity of PET, have been studied in the amorphous and crystalline regions. The profiles of the 382 cm-1 band and the 1020 cm-1 band for a series of specimens annealed at different temperatures. Consistent results were obtained from both bands for the compositions of the three conformers, i.e., the trans conformer in the crystalline state and both the trans conformer and the gauche conformer in the amorphous state (365). Poly(ethylene 2,6-naphthalate) (PEN) film containing alpha, beta and amorphous phases were prepared, and the amorphous contribution digitally subtracted to yield the characteristic spectra of the amorphous, alpha, and beta phases. In other words, the amorphous spectrum is determined by melting the polymer, so after subtraction, one knows the spectrum of all of them. The alpha crystal form adopts an all-trans conformation, while the beta crystal form adopts a conformation with appreciable gauche character. Conformational changes in PEN occur due to the rotation of the naphthalene ring as well as rotation of the ethylene glycol units. The normalised absorbances of the bands at 824 and 814 cm-1 were correlated to polymer density, and can be used to represent the amorphous and alpha crystalline phases, respectively (56).

7.3.5 Nematic Ordering in Polymer Dispersed Liquid Crystals Real-time FTIR was used to study the curing of a UVcurable prepolymer (NOA65) and its mixtures with liquid crystals. Curing reactions were examined as a function of film thickness, temperature, and liquid

19

Infrared and Raman Spectroscopy of Polymers

crystal content. While there was little dependence of the curing behaviour on the thickness of the film, the effect of temperature was strong. Curing rates exhibited a maximum around 325 K, while conversions reached a plateau about 20 K higher. Liquid-crystal addition depressed the conversion. However, compared with the neat matrix, the final conversion was significantly lower only for phaseseparating concentrations. The rate of reaction decreased, and the induction period for the onset of polymerising reactions increased, with increasing liquid-crystal concentration (38). Nematic ordering can be observed and quantified based on a change in a characteristic band of the liquid crystal. Moreover, the phase separation and the onset of nematic ordering can be temporarily resolved. The conversion at phase separation decreased strongly with an increase in liquid crystal content, while the conversion required for phase separation increased with increasing temperature. The fraction of liquid crystal present as nematic droplets and total fraction of nematic domains in NOA65 were quantified from changes in the vibrational spectrum of the liquid crystal (E7, which refers to the commercial label for the liquid crystal) (37).

7.4 Quantitative Analysis The primary result of IR transmission spectroscopy is the transmittance of the cell plus sample, (It)/(Io),

where Io is the intensity incident on the cell and It is the intensity which leaves the cell, both measured outside the cell (Figure 4). The absorbance is calculated as -log10 (It)/(Io) and is equated with EmCl, the molar absorption coefficient (Em) multiplied by the concentration (C) multiplied by the pathlength (l) through the liquid. This is the Beer-Lambert law. The absorbance is a measure of energy lost from the radiation beam solely because of absorption by the sample. The experimental absorbance is a measure of the energy lost because of absorption by the sample, plus the energy lost because of reflection from the interfaces of the cell plus the energy lost because of unexplained baseline errors. The energy lost because of unexplained baseline errors may be positive or negative. Quantification requires knowledge of the beam path through the sample. Hence, the sample often needs to be modified to allow for a known geometry. Spectral subtraction, least square regression analysis, PLS and spectral deconvolution are some of the spectroscopic techniques widely used to quantify constituents in a multicomponent sample. For almost any type of spectroscopic analysis, this is usually the first step. It is especially important for polymers given the variations in spectra for the same polymer due to molecular weight, conformation, crystallinity, sample preparation, age and sampling method.

Figure 4 Transmission IR sampling techniques

20

Infrared and Raman Spectroscopy of Polymers

7.5 Copolymer Composition and Structure Direct measurement of absorbance of different functional groups, measurement of end groups, analysis of specific interactions and monomer concentration can all be used to monitor quantitative copolymer composition. Copolymer composition is determined by using the absorbance intensity ratio of monomer specific vibrational modes of vibration. A number of copolymer systems have been investigated: Copolymer system

item/no.

epichlorohydrin-gylicidyl ethers

(28)

ethylene-acrylate

(184)

EVA

(72)

EVA

(141)

ethylene-vinyl alcohol

(258)

ethylene-propylene

(110)

ethylene-propylene

(123)

ethylene-propylene-diene (EPDM)

(155)

acrylic/methyl methacrylate

(124)

formaldehyde-phenol

(127)

2-((phenylamino)carbonyl)-oxyethyl methacrylate

(338)

maleic anhydride-styrene

(343)

techniques are fast and can monitor the conversion curves in real time. IR and Raman techniques can determine in the course of the process the polymerisation and copolymerisation rates in the course of the process separately for each monomer by measuring variations in the intensity of IR and Raman bands of the reacting groups. In situ IR and Raman fibre optic probes can be placed at specific locations within the growing polymer to target the evolution of polymerisation chemistries at the surface or core of the process. The vibrational techniques of IR and Raman spectra permit better identification of spectral differences between monomer and polymer. The specificity of the technique, the speed of data acquisition and the portability of equipment all make this method ideal as a tool to fundamentally probe how the distribution of individual chemical species change during the polymerisation. Its utility is in understanding the mechanism of a polymerisation including modifications including a catalyst or novel formulations and changes in the polymerisation conditions. The kinetic parameters can be evaluated and the models for the polymerisation mechanism developed. Isothermal experiments can be performed for a series of reaction temperatures and used to determine the overall activation energy of the polymerisation reaction.

7.6.2 Examples Using IR Fibre Optics 7.6 Polymerisation Kinetics and Mechanism in Multicomponent Systems 7.6.1 Approach The synthesis of polymeric materials from lower molecular weight materials usually involves IR or Raman characterisation at some stage. The complete spectrum of a reacting species can lead to information of the concentration of each species involved without the need to stop the reaction or disturb it in any manner. The sample may be easily heated, exposed to UV, or exposed to electrical and magnetic fields or lasers with minor customisation of the sample holder (all in situ and for most reactions) in real time. Hence, these techniques are used to characterise the polymerisation process for many systems. Real-time chemical processing and analysis yields improvement in product consistency and quality while maximising process efficiency. IR and Raman spectroscopic techniques can be used for the study of kinetics of copolymerisation and terpolymers. These

Isobutylene polymerisation initiated by 1,2-epoxy2,4,4-trimethylpentane (TMPO-1)/TiCl4 was studied using IR fibre optics. The initiating mechanism involves the formation of tertiary carbocations, by both SN1 and SN2 paths. From the linearity of the first-order plots of monomer consumption, and the near uniformity of the polyisobutylene, it was concluded that living polymerisation conditions prevailed (i.e., no termination step) (32). The ATR head can monitor very low concentrations (0.1 mmol/l) (49). A linear-chained epoxy resin was formulated from phenyl glycidyl ether and nadic methyl anhydride, catalysed by benzyldimethylamine (248). An IR fibreoptic probe was used to follow the conversion of a thermosetting tetrafunctional epoxy resin in which the hardener was an aromatic diamine and a carboxylic dianhydride. A polymerisation system consisting of a cycloaliphatic diepoxide, epoxidised natural rubber (ENR), glycidyl methacrylate (GMA) and a cationic photoinitiator, triphenylsulfonium hexafluoroantimonate, was studied (75). Multifunctional epoxy/ amine formulations (Epon 825 plus 4,4'-methylene-

21

Infrared and Raman Spectroscopy of Polymers

dianiline) were examined by NIR spectroscopy (276). The polymerisation of bisphenol A diglycidyl ether and tetraglycidyl diaminophenyl methane and amine curing agents, i.e., 4,4'-methylenedianiline and diaminodiphenyl sulfone, were studied using near IR methods (277). Using an embedded silica optical fibre monitored in situ by evanescent wave spectroscopy, the epoxy ring-opening and crosslinking reactions could be followed in real time (217). IR-transmitting optical fibres as evanescent wave sensors (59) were used to study rigid PU/polyisocyanurate foam formation using new catalysts promoting different phases of PU foam.

7.6.3 Examples Using Raman Fibre Optics Raman fibre optics has been used to study the emulsion homopolymerisations of styrene and n-butyl acrylate (35). An IR spectroscopic technique for the examination of radical copolymerisations of acryl and vinyl monomers was developed. A comparative study of the copolymerisation of model monomer pairs was made using monofunctional and polyfunctional compounds. The data established the role of structural-physical transformations, involved in the formation of crosslinked polymers, on the copolymerisation kinetics and on the nonuniformity of distribution of crosslinks in the copolymers formed (151). Raman fibre optics of polymerisation of acrylic terpolymers was also used to monitor as well as an on-line measurement of morphology/composition (66). The high temperature (330 °C) cure reaction of 4-phenoxy-4'-phenylethynylbenzophenone was monitored using a modulated fibre optic FT-Raman spectrometer (80). The time-dependent evolution of the polymerisation and copolymerisation reactions of styrene/unsaturated polyester resin was characterised using optical levitation with Raman spectroscopy (135). The nbutyllithium-initiated anionic polymerisation of styrene in ethylbenzene was measured using Raman spectroscopy (214).

(363). Changes in the FT-Raman spectrum of 1,4-bis(3quinolyl)buta-1,3-diyne as a function of gamma-ray dosage are used to monitor the degree of monomer to polymer conversion in a solid-state topochemical polymerisation reaction (i.e., polymerisation directed by the solid-state structure) (315).

7.6.4 Examples Using Rapid Scan FTIR Spectroscopy An IR technique can obtain spectra every 5-10 seconds of a reacting PU foam system having a given temperature profile (360). The real-time IR spectroscopy method was found to be particularly useful for analysing high conversion kinetics. Results were obtained also for poly(ethylene glycol 200) dimethacrylate and poly(ethylene glycol 600) dimethacrylate (263). FTIR spectroscopy was applied to the study of polymerisation kinetics of simultaneous interpenetrating polymer networks composed of PU and vinyl ester resin (238). The comparison of vinyl ester resin with or without its pendant hydroxyl groups was also made to examine the intercomponent chemical binding effect. The copolymerisation of N-cyclohexylmaleimide (CHMI) and methyl methacrylate (MMA) using azobisisobutyronitrile as the initiator using rapid scan IR. Using the Mayo-Lewis equation, the reactivity ratios of CHMI and MMA were calculated (64). By measuring the presence of functional groups at finite depths from the crystal surface by real time ATR-FTIR spectroscopy, the conversion during acrylate polymerisations was measured. By varying the film thickness, the reactivity of multiacrylates could be spatially resolved (262). The simultaneous monitoring of vinyl acetate (VA) and erucamide additive concentrations in EVA copolymers was undertaken with NIR spectroscopy using an in-line flow cell attached to an extruder (130).

Raman experiments were performed on cationic photopolymerisations of a divinyl ether initiated with a diaryliodonium salt of hexafluoroantimonate photosensitised by anthracene. Isothermal Raman experiments were performed for a series of reaction temperatures and were used to determine the overall activation energy of the polymerisation reaction (240).

Monitoring the imidisation of a polyamic acid made from 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA) and p-phenylenediamine (PDA) was accomplished using IR spectroscopy (115).

A Raman spectrophotometer was used to measure in situ the polymerisation rate of acrylamide photoinitiated by hydrogen chromate anion in aqueous solution upon irradiation by laser beam (ionised argon)

FTIR spectroscopy was used with a common kinetics program to monitor the two separate reactions occurring during thermal curing of acetyleneterminated polyisoimide prepolymer (242).

22

Infrared and Raman Spectroscopy of Polymers

By the use of NIR instrumentation designed specifically for the process environment, the isocyanate content of a urethane polymerisation reaction is monitored in realtime (265). The cure mechanism for curing triglycidyl p-amino phenol with diaminodiphenylsulfone was studied. The concentration of primary and secondary amine and epoxide groups were monitored directly as a function of cure with NIR spectroscopy. In similar fashion, monitoring of the percent conversion of methyl methacrylate to PMMA in situ in a mould used shortwavelength NIR spectroscopy. NIR spectroscopy was also used to monitor conversion during conventional, anionic solution polymerisation of styrene and isoprene to homopolymers and block copolymers (314). FTIR spectroscopy was used to study the polymerisation of random copolymers of 4-vinylphenol with n-alkyl methacrylates which were prepared by free radical copolymerisation of 4-t-butyldimethylsilyloxystyrene and the corresponding alkyl methacrylates in benzene at 60 °C using azobisisobutyronitrile (AIBN) as an initiator (321). The thermal reaction of polyphenylene-1,2-dibromoethylene under argon flow was investigated using in situ kinetic IR spectroscopy (345). Stopped-flow FTIR spectroscopy was used to follow group transfer polymerisation (GTP) and cyclic oligomeric carbonate formation. The effect of catalyst structure, propagating end stereochemistry and degree of polymerisation on the rate of monomer addition in GTP was investigated (329).

high molecular weight polymers. As most polymer pairs are immiscible, they form multiphase systems with weak physical and chemical interactions across the phase boundaries. As a result, immiscible blends exhibit poor mechanical properties. Miscibility in polymer blends results from the Gibbs free energy of mixing (ΔGm) being a negative value. This term combines the effects of both entropy and enthalpy. It has been well established that the former generally has a weak contribution in the case of polymers because of their high molecular weight. The latter is related to interactions occurring at the segmental level between polymers and mainly dominates the miscibility of the blends.

7.7.2 Miscible Blends 7.7.2.1 Compatibilised Blends Compatible blends are two-phase materials with properties controlled by the properties and geometry of each phase and the nature of the connectivity between phases (compatiblilisers modify/improve the interface). In some cases, the addition of small amounts of an A/B copolymer compatibiliser will result in a compatibilised A-B blend morphology that has improved mechanical properties. The compatibiliser is considered to be located mainly at the interface between the two immiscible polymers, where it induces local miscibility. The compatibliser lowers the interfacial tension and allows the dispersion of the incompatibile homopolymers into small, microscopic domains. The following blends have been studied:

7.7 Polymer Blends 7.7.1 Utility of Polymer Blends Many practical benefits can be obtained by blending polymers. Blending allows for the beneficial properties of two polymers to be combined in one material while shielding their mutual drawbacks. Deviations in the rule of mixing can lead to properties of the blend over and above those of its components. Thus, processibility, chemical and environmental resistance, adhesion, and mechanical properties of polymer blends are superior to those of their homopolymers. The attractiveness of blending lies in the propertytailoring possibilities. However, most binary mixtures of polymers are not miscible on the molecular level because the entropy of mixing is not favourable for

• PP-LDPE with poly(propylene-g-maleic anhydride) and poly(ethylene-co-vinyl alcohol) as in situ reactive compatibilisers (117), • PET-LDPE compatibilised with diethylmaleate grafted polyethylene (120), and • EVA copolymer compatibilised with terpene-phenol resins (TPR) (165).

7.7.2.2 Reactive Blends Reactive blending is an important method for the compatibilisation of polymer blends. Two or more immiscible polymeric components are functionalised with chemical units that are coreactive. During melt

23

Infrared and Raman Spectroscopy of Polymers

processing, the polymers chemically react to form a copolymer at the interface between the two phases. This copolymer reduces the interfacial tension between the two phases, provides for better dispersion, and promotes adhesion between the two phases. A highly crosslinked epoxy resin was modified by reactive blending with bisphenol A polycarbonate. The bisphenol A polycarbonate was dissolved at high temperature in the uncured epoxy resin before the curing process. The physical and chemical interactions between the two components were studied by IR. Isothermal measurements showed that the presence of polycarbonate did not affect the overall curing mechanism but decreased both the initial reaction rate and the final conversion of reactants (278).

7.8 Conducting Polymers The 2000 Nobel Prize in chemistry was awarded to Heeger, MacDiarmid and Shirakawa for turning polymers which are traditionally insulators into conductors. They found that by doping polyacetylene, it became conducting. This discovery resulted in the establishment of new types of organic materials that combine the processing and mechanical advantages of plastics with the electronic and optical properties of metals and inorganic semiconductors. Considerable effort has been directed at determining the structural basis of this unusual observation. The chemical structure of electrically conducting polypyrrole films doped with p-toluene sulfonate and dodecyl sulfate was studied by FT-Raman spectroscopy. The spectra were compared with those from the corresponding reduced polymers after dedoping and found to be consistent with polaron and bipolaron descriptions of the electron transport mechanism in polypyrrole (331). Resonance Raman spectroscopy was used to investigate the products formed upon iodine doping of cispolyisoprene. Evidence for the production of polyenes was found and that these are in part responsible for the increased conductivity of iodine-doped cispolyisoprene (374). In situ Raman studies of the conducting and nonconducting poly-n-vinylcarbazole showed that the conducting polymer had a 3,3'-dicarbazyl structure formed by dimerisation at the 3,6 position. The conducting polymer was also obtained by electrolysis of the nonconducting polymer dissolved in

24

dichloromethane. The conducting polymer obtained by this method was found to have a similar structure to that obtained by direct electrolysis of the monomer. These spectra showed that there were no significant structural changes occurring in the conducting polymer during the polymerisation process (292).

7.9 Emulsion Polymers Emulsion polymerisation is characterised by the fact that a free radical initiator (usually water-soluble) is used to polymerise free radically polymerisable monomers to give a water-insoluble polymer. The main ingredients of an emulsion polymerisation system include monomer, dispersant, emulsifier and initiator. Water is often used as the dispersant. A water-insoluble monomer can be dispersed in water by means of an oil-in-water emulsifier and polymerised with a watersoluble initiator. Styrene, MMA and VA are systems for which emulsion polymerisation are commonly used. An important characteristic of emulsion polymerisation is that, unlike other polymerisation processes, the polymerisation rate and molecular weight can be increased at the same time. This is due to the compartmentalisation of the system that reduces the probability of mutual termination of the propagating radicals. The behaviour of this compartmentalised system depends on the rate of exchange of species between the elements of the system. Emulsion polymerisation gives particles in the diameter range ~50-500 nm, with the ability to accurately control particle size. Particle stability is usually achieved through the use of surfactants. The direct analysis of the organic phase of an emulsion polymerisation is possible. Quantification involves using the bending mode peak of water, which makes up the bulk of the reaction medium, as an internal standard. The process is demonstrated for MMA but is generally applicable to emulsion polymerisations. It does not require the introduction of an extraneous internal standard component into the reaction mixture (319). FTIR spectroscopy was used to study hydrogen bonding in films of PU and core shell type polyacrylate-PU microemulsions. The effects of hydrogen bonding on composition and core shell ratio, and its relationship to crosslinked structures (Type A and B) was revealed (60). PS microspheres, produced by microemulsion polymerisation, generally contain only one or a few

Infrared and Raman Spectroscopy of Polymers

polymer chains, and may thus be termed single- or pauci-chain microspheres. Changes in chain conformation on heating were studied using in situ FTIR spectroscopy (85). The phase transition between micellar phases of polyethylene oxide-polypropylene oxide-polyethylene oxide) (PEO-PPO-PEO) triblock copolymer in aqueous solution was investigated as a function of temperature using FTIR spectroscopy. As the temperature increases, PO blocks appear to be stretched conformers with strong interchain interactions, and the formation of a hydrophobic core in the micellar phase. The EO chains are found to change to a more disordered structure with low-chain packing density. Both the EO and PO blocks exhibit dehydration during the phase transition (78). Using a thermal micro ATR/FTIR spectroscopic system, a quantitative investigation was made of the molecular interactions in aqueous solutions of poly(Nisopropylacrylamide) (PNIPAAM). The results indicated that intermolecular interactions predominate between PNIPAAM and water at temperatures below the lower critical solution temperature (LCST). However, above the LCST, PNIPAAM molecules in water are aggregated because of intramolecular interactions and hydrophobic interactions in the system (93). The nature of the complexes formed by the interactions between polyacrylic acid (PAA) and polymethacrylic acid (PMAA) with poly(4-vinylpyridine) and poly(2vinylpyridine) in ethanol/water solution was studied using FTIR spectroscopy. The PMAA complexes involved hydrogen-bonding interactions, while there was evidence of ionic interactions in the PAA complexes. This difference in the behaviour between the complexes is attributed to the higher acidity of PAA compared with that of PMAA (140). The FTIR spectra were acquired as functions of water content in the range 2.6-38 wt% and temperatures in the range 300-373 K for hydrated poly(2-hydroxyethyl methacrylate) (PHEMA). The results suggest two types of water in the hydrogel polymer system, tightly-bound water and loosely-bound water. At low concentrations, water was mainly hydrogen-bonded to the polymer (tightly-bound water). At water concentrations greater than 18 wt%, however, part of the water existed in a different form and behaved as loosely-bound water. It was also suggested that some of the water continued to be hydrogen bonded to the polymer until at least a temperature of 373 K when the bulk water should have evaporated. FTIR spectroscopy was found to yield greater site-specific insight into the local behaviour of water in hydrated PHEMA (185).

The partitioning of acrylonitrile between particles and the aqueous phase of polybutadiene latex was measured by Raman spectroscopy using rubber latex as substrate. Raman line intensities yielded the partition values in the two phases (295).

7.10 Graft Polymers Graft copolymers can be prepared by radical grafting of a polymerisable monomer A onto a reactive polymer backbone B. As a result of the grafting reaction, a complex product is obtained comprising the graft copolymer AB, residual ungrafted polymer backbone B and homopolymer A. The condensation grafting of polyethylenimine (PEI) onto poly(acrylamide-co-acrylic acid) (PAM-co-AA) was studied by FTIR spectroscopy. The reaction mechanism, which proceeded by a two-step reaction, involved the conversion of AA to acid chloride (AC) using thionyl chloride, followed by the condensation of AC onto PAM and with amine onto PEI to form the graft copolymer (125). The grafting of PP films by PAA was demonstrated to start from the interface between the PP and the polymerisation solvent. The results suggested that it should be possible to control the location of grafting both by the content of antioxidants and by their extraction (322). LDPE was functionalised in the bulk through dicumyl peroxide-initiated grafting of dibutyl maleate and vinyltrimethoxysilane in the temperature range from 140 to 200 °C (327). The structure of EPDM grafted onto polyamide 66 was analysed by FTIR spectroscopy. Evidence indicated the presence of cyclic imide groups, derived from grafted maleic anhydride groupings (229). Polyglycidyl methacrylate and their copolymers obtained by radical graft onto polyvinyl alcohol (PVAL) fibres were studied by IR spectroscopy. The spectra regions sensitive to the sites of localisation of the chains of grafted poly(glycidyl methacrylate) are within 3600-3100, 1450-1300, 1120-1000 and 700500 cm-1, which correspond to the stretching and bending OH vibrations, stretching carbon-oxygen vibrations, and torsional vibrations of the hydroxyl groups, respectively. On this basis, it was established that grafted polyglycidyl methacrylate molecules are linked to PVAL macromolecules via oxygen atoms of hydroxyl groups (255).

25

Infrared and Raman Spectroscopy of Polymers

The use of an intermediate barrier layer to vary the penetration depth in an ATR experiment was used in probing concentration profiles away from the interface, Application of this technique in the study of PMMA/ PDMS graft copolymers deposited onto a copper oxide surface indicated a preferential presence of the siloxane component at the oxide interface; a concentration gradient was observed to decrease with increasing distance into the bulk of the sample film (275). IR spectra of polycaproamide fibre, polyglycidyl methacrylate and polycaproamide fibre grafted with polyglycidyl methacrylate were recorded. The spectral regions that were sensitive to localisation of the chains of grafted polyglycidyl methacrylate were identified, i.e., 3500-3100/cm-1 (stretching vibrations of NH groups), 1700-1500/cm-1 (Amide I and Amide II absorption bands), 1030-900/cm-1 (Amide IV) and 720640/cm-1 (Amide V). It was found that polyglycidyl methacrylate was grafted to the macromolecules of polycaproamide via an amide nitrogen (308). ATR-IR spectroscopy was used to characterise the grafting of PP films by PAA. It was shown that grafting always started from the interface between the PP and the polymerisation solvent. The results suggested that it should be possible to control the location of grafting both by the content of antioxidants and by their extraction (322). LDPE was functionalised in the bulk through dicumyl peroxide-initiated grafting of dibutyl maleate and vinyltrimethoxysilane in the temperature range from 140 to 200 °C. The degree of grafting was determined by IR spectroscopy. The total surface energy increased with grafting. The surface energy of the silane-grafted PE was found to be lower than that of dibutyl maleategrafted PE (327).

7.11 Degradation of Polymers The lifetime of many polymer products in use is limited by oxidative degradation. Exposed samples are usually non-uniformly oxidised. At the macroscopic level, the heterogeneities can result from oxygen-diffusionlimited effects. If the rate of oxygen consumption exceeds the rate of oxygen permeation, oxidation occurs in the surface layers, whereas the core remains practically unoxidised. The importance of this effect depends on several parameters. First, intrinsic parameters are linked to material geometry (e.g., sample thickness) coupled with the oxygen consumption rate, which depends on the reactivity of

26

the polymer, the presence of additives, and the oxygen permeability of the material. Second, extrinsic parameters such as the conditions of accelerated ageing and the oxygen pressure during ageing are important. Oxidation is accelerated if the temperature is elevated. Exposure to optical and UV radiation can also accelerate the degradation. Additionally, the thermooxidation and photooxidation are accelerated by generating chemical effects by the application of mechanical forces (i.e., mechano-chemical degradation). Vibrational spectroscopy is particularly useful for studying the degradation processes as the measurements can be made in real time.

7.11.1 Degradation with Ionising Radiation IR spectroscopy was used to follow the ageing processes of two types of epoxy resins. Resin samples were exposed to ionising radiation and the effects at the molecular level were determined. Aromatic amine cured resins were only slightly affected by the radiation, but those cured by alkyl diamines were more sensitive and thus absorbed more water molecules (41). The effect of radiation dose and the hydrolysis conditions on the chemical structure of electron irradiated PTFE was studied. Irradiation produced acid fluoride (COF) groups and, under ambient conditions, these hydrolysed with atmospheric humidity to form free and associated carboxylic acid (COOH) groups. The concentrations of these groups were different in the near-surface and bulk regions. The formation of carboxylic groups in different states of association depended on the hydrolysis conditions (146). IR spectroscopic analysis showed that the treatment of PAN films and fibres by gamma-irradiation led to cleavage of the polymer chains forming carbonylcontaining functional groups, the composition of which depended on the treatment conditions (330).

7.11.2 Degradation by Photooxidation The photooxidative degradation of anhydride-cured epoxies was studied. The degradation was heterogeneous, the surface being much more affected than the bulk. The disappearance rate of aromatic groups was dependent only upon their initial concentration, while the formation kinetics of hydroxyl groups was determined by the diffusion of oxygen into the material. The formation of hydrophilic products,

Infrared and Raman Spectroscopy of Polymers

acids, and alcohols was confirmed by chemical treatment, and it was concluded that their presence and high concentration at the surface could be responsible for the degradation of the insulating properties of epoxies when used as electrical insulators (112).

decomposition reaction was linear polymerisation of the nitrile group, with cyclisation followed by extended conjugation being a significant exothermic process. There was no evidence of the formation of oxygencontaining chromophores (113).

PS films were exposed to radiation of long wavelength (above 300 nm) and short wavelength (253.7 nm) under atmospheric oxygen. Changes in the FTIR spectra of the photooxidised samples were followed. The absorption maxima which were found in the carbonyl and hydroxyl regions of the IR were assigned, and the corresponding photoproducts were identified (351).

The thermooxidative degradation and SiO x film formation of poly(vinyl imidazole-co-vinyl trimethoxysilane) on copper was investigated. Thermal degradation of the copolymer was catalysed by copper in the film and at the substrate surface. Copper in the copolymer film contributed to the formation of a copper-containing SiO x film during thermal degradation. Copper oxides in the film interacted with the SiOx film to form a copper-rich phase near the film defects and cracks (142).

IR spectroscopy was used to study the microstructure of propylene-ethylene copolymer samples taken from seats which had degraded during storage or aged during outdoor exposure in an Olympic stadium in Barcelona over a period of 2.5 years. The changes observed included increases in aldehyde and ketone groups and decreases in unsaturation, peroxide, methyl and methylene groups and isotacticity. The results indicated that the main processes taking place were photooxidation and chain scission (189). The photooxidation of a nonwoven PE fabric showed hydroperoxide, alcohol, aldehyde, ketone, carboxylic acid, and anhydride groups were formed as the products of the photooxidation of the PE fabric and the relative amount of carboxyl increased as the photooxidation progressed. Distribution of the photooxidation products was inhomogeneous between the two surfaces of the fabric. The UV radiation at 254 nm caused photooxidation of PE. No photooxidation was observed in the fabric exposed to the UV radiation at 350 nm under the same conditions (288). PEO and polymethyl vinyl ether were UV irradiated in hydrogen peroxide solutions. Hydroxy and hydroperoxy radicals accelerate the oxidative degradation of these polymers. Hydroxy and possibly hydroperoxy radicals can abstract hydrogen from methylene groups in both polymers. As a result of further oxidative reactions, different carbonyl, hydroxy and hydroperoxy groups are formed (297).

7.11.3 Degradation by Thermal Oxidation Processes During thermal degradation of PAN over the temperature range 150-590 °C, gaseous and volatile products were produced with simultaneous stabilisation of the structure of the residual material. The principal

The thermal degradation (in vacuo, up to 500 °C), of a VA-methacrylic acid copolymer having 65% alternating units, and of the corresponding homopolymers, was studied. Polyvinyl acetate (PVA) copolymer crosslinks form due to double bond formation through deacetylation. PMAA generates little unsaturation, rather crosslinks by intermolecular anhydride formation. It decomposes above 350 °C when the anhydride breaks down with substantial chain scission. In the copolymer, both types of crosslinking reactions are disturbed by lactone formation between alternating VA and methacrylic acid units. The lactone formation protects the VA units from deacetylation and competes strongly with anhydride formation (273). The thermooxidative degradation of polyphenylene bibenzimidazole (PBI) and a blend of PBI with Ultem 1000 polyetherimide was investigated. The FTIR spectra of the blend were analysed by subtraction spectroscopy, allowing the fate of the two blend components to be selectively studied. No chemical interaction between the two components was detectable by FTIR spectroscopy during the degradation process (323).

7.11.4 Degradation by Chemical Exposure The mechanism responsible for the hardening of hydrogenated nitrile rubber automotive seal compounds on prolonged exposure to automatic transmission fluids at high temperature was investigated. The increase in hardness was found to result primarily from chemical attack at the acrylonitrile sites. This chemical attack first resulted in the formation of isocyanide or isonitrile ions. The proposed mechanism involved crosslinking at the acrylonitrile sites through the formation of isonitrile ions and the subsequent formation of imides.

27

Infrared and Raman Spectroscopy of Polymers

The isonitrile intermediate formed ionic bonds resulting in the formation of an ionomer once the concentration became sufficiently high. Ultimately these ions crosslinked to form imides in the presence of oxygen or water. It was proposed that the increase in hardness was due to the formation of the ionomer and the imides (154). Differences in bands assigned to carbonyl groups and hydroxyl groups in PET films aged in water suggested formation of different hydrogen-bonded species. The autocatalytic nature of the hydrolysis in water was confirmed and evidence for the so-called ‘chemicrystallisation effect’, with crystallinity increasing with degradation, was observed (50).

7.11.5 Analysis of Evolving Gases from Polymers A large number of different techniques are used to analyse fire gases including gas chromatography, mass spectrometry, and IR absorption. FTIR spectroscopy can be used for on-line quantification of evolved gas species during heating, burning, and smouldering of the sample. The use of FTIR spectroscopy enables a number of the more important gases to be determined continuously. Evolved gas analysis reveals features due mainly to the corresponding monomers or stable, volatile and low relative molecular weight degradation products. These gases include those of particular importance to PU foam containing fires, e.g., hydrogen cyanide, nitrogen oxides, hydrogen chloride and hydrogen bromide (from flame retardant additives) as well as carbon monoxide and carbon dioxide which are produced from all fires (236). The IR absorption spectra are used to identify the individual gas species within the fire gas mixture and the intensities of the absorption bands are used to quantify the gas concentrations. Linear-temperature controlled pyrolysis with subsequent analysis of the pyrolysates (volatiles and residues) by FTIR spectroscopy can provide information on the thermal degradation mechanisms of polymers including aromatic polyesters (325). Thermal analysis of PS, poly-p-methylstyrene and poly-α-methylstyrene was carried out using evolvedgas IR analysis (302). On decomposition, the polybutylene terephthalate (PBT) polymers give off mainly water, carbon dioxide, butadiene, tetrahydrofuran (THF) and PBT oligomers. The flame retardants marginally increased the polymer decomposition temperature (274).

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7.12 Orientation of Polymer Chains Due to External Perturbations 7.12.1 Approach using Vibrational Spectroscopy The elucidation of the mechanisms and dynamics of segmental mobility in polymers under the influence of external perturbations can contribute to the optimisation of the engineering properties of technically important polymeric materials. Application of a uniaxial or bidirectional stretching is a common method of treating a polymeric material to improve its mechanical enduse properties. Generally, time-resolved IR spectroscopy has proved an extremely valuable tool to investigate the structural details of molecular changes incurred by a polymer under the influence of such an external perturbation. The ability to monitor and model such drawing and relaxation processes would benefit greatly product quality and web efficiency. FTIR and Raman spectroscopy are two of the few techniques providing data on the crystallisation, orientation and conformational changes of a polymer during and after mechanical treatment. Front-surface reflection IR spectroscopy is often used to characterise the structure of drawn samples. This approach provides the complete IR spectrum, including the highly absorbing bands that are often saturated in transmission spectra. ATR techniques are used to depth profile the changes in orientation. One approach to characterising the molecular orientation in both uniaxially and biaxially oriented samples of PET makes use of the ratio of the absorption bands near 1250 and 1725 cm-1, the first of which shows parallel dichroism and the second perpendicular dichroism. An equation is developed that relates this ratio to the molecular orientation with respect to the direction of measurement. Thus, it is possible to determine individually the orientation functions with respect to the machine and transverse directions (131). Several sources of error may influence the calculations of chain orientation carried with the use of data from IR dichroism experiments. Three specific problems are the improper treatment of chain conformation, the imperfect polariser behaviour, and the inaccurate assumptions regarding the value of the angle between a particular IR-active transition moment and the polymer chain axis (309).

Infrared and Raman Spectroscopy of Polymers

7.12.2 Orientation Functions for Mechanical Deformation FTIR spectroscopy was used to monitor orientation phenomena in highly crosslinked epoxy/amine networks during uniaxial deformation above their glass transition temperature (Tg). The resins were prepared from the diglycidyl ether of bisphenol A and various polyether di- and triamines in order to examine the influence of the structure of the network formed. The molecular orientation was studied in relation to network density and structure. The orientation behaviour was mainly determined by the flexibility of the polyether chain and the homogeneity of the network structure. The epoxy resins were also subjected to successive loading-unloading cycles. The results showed that the orientation of epoxy networks in their rubbery state was completely reversible and that no significant fatigue due to gradual chain rupture occurred until sample failure (253). IR dichroism was used to study the orientational development in the high-speed spinning of Nylon 66 yarns. A relationship between IR dichroism and orientation factor was developed and a correlation between orientation measured by IR and X-ray diffraction demonstrated (372). The orientation functions and dichroic difference data for a commercial polyester-urethane from B.F. Goodrich showed that, in static stretching, the soft domains reached orientation saturation before the hard domains. On the timescale of the static experiment, plasticisation diminished the ability of both domains to reorient, while the plasticiser itself did not orient (55). Micro-Raman spectroscopy was used to study the structural changes which occur in the cold-drawing of HDPE. The cold-drawn structure was highly orientated and a large decrease in the Raman orthorhombic crystallinity was observed. The results indicated an ill-defined orthorhombic crystalline structure with dislocations and disrupted crystals formed by cold-drawing, possibly resulting from molecules being pulled through the crystals. No disruption was observed in fibrils created during environmental stress crack resistance (ESCR) tests at 348 K. Temperature was an important parameter in the crystalline phase recovery of the orthorhombic crystallinity and when the cold-drawn HDPE was annealed, the monoclinic phase disappeared (94). The role of an ESCR detergent (active environment) during tensile deformation of PE samples was studied. IR spectroscopy indicated that the detergent was predominantly present within the transition fronts of

the material. The results indicated that the environment penetrated the sample during the necking process and stabilised crazing (99). ATR-IR spectroscopy at various angles of incidence was used to study ultradrawn films of PE. A gradient of molecular and crystalline structures was found from the surface into the core. The skin was highly orthorhombic. Moving inside the film, both monoclinic and orthorhombic lattices coexisted. A new phase with isolated trans-planar sequences was observed in the core. Various kinds of collective and oriented or isolated conformational disorder were identified. A molecular model was proposed for the process of orientation during drawing (346).

7.12.3 Strain-Induced Crystallisation The morphology of the strain-induced crystalline material produced by drawing amorphous PET is different from that of material obtained by thermal crystallisation. Furthermore, it has been shown that thermal crystallisation involves two distinct stages. The primary stage starts to become significant around 90 °C not far above the Tg, and shows a sigmoidal dependence on log (time). The secondary stage becomes significant only above about 140 °C and shows a linear dependence on log (time). Significant differences between samples with strain-induced crystallinity and one that was thermally crystallised are observed (90). Specular reflection spectra (spectra obtained using specular reflection sampling) was obtained from the surface of uniaxially drawn PET samples. The overall orientation function and content of trans-conformers is calculated. The results are correlated with mechanical modulus and crystallinity values (251). In uniaxially drawn PET films the skeletal structures, such as the CO bond in the ethylene glycol unit and the phenyl ring, are susceptible to deformation by mechanical stretching, while the dynamic structural changes around the methylene group are small. It was assumed that the backbone of the polymer is responsible for the change of the mechanical properties induced by the drawing of the film (158). The structure of poly(3-hydroxybutyrate-co-3hydroxyvalerate) fibres exhibit three crystalline structures: two orthorhombic, and one pseudohexagonal. The orthorhombic crystals with the c-axis preferentially orientate perpendicular to the fibre axis, and pseudo-hexagonal crystals are preferentially formed in the drawing process (114).

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Infrared and Raman Spectroscopy of Polymers

7.12.4 Deformation-Induced Conformational Changes PVC films were stretched to various elongation ratios and the dichroic behaviour of 615 and 637 cm-1 bands of the IR spectrum were investigated. The evolution of the dichroic ratios and of the relative absorbance of the bands in the direction perpendicular to that of stretching were compared so the occurrence of local chain orientation related to the conformational change from gttg-tt to gtgttt which occurs when PVC is stretched (51). FTIR polarisation spectroscopy was used to study the orientational behaviour of the different constituents of a liquid crystalline block copolymer (copolyesterimide) during uniaxial elongation at different temperatures. Differences in the degree of alignment (as well as in the response to the application of the mechanical load) were observed. With increasing temperature, the level of the applied stress and the induced degree of orientation decreased, while the differences in the orientational behaviour of the mesogen and the flexible spacer were retained (243).

7.12.5 Relaxation Processes after Drawing Epoxy resin films were subject to various successive loading-unloading cycles including elongation, recovery, annealing and stress relaxation to study the reversibility of the orientation during relaxation processes (197). The relaxation of the segmental orientation and the chain extension in polycarbonate was studied by IR dichroism and heat shrinkage after a step strain deformation to a draw ratio of 1.75. This made it possible to distinguish between local relaxation mechanisms and large-scale relaxation mechanisms of the molecular orientation. It was found that the average relaxation time for segmental orientation is shorter and more temperature-dependent than the average relaxation time for the chain extension. The segmental orientation relaxes almost totally at 170 °C (Tg 148 °C) before the chain extension even starts to relax (201).

7.12.6 Electric Field Induced Reorientation of Polymers Dipole reorientation under the influence of an electric field has been studied in oriented Nylon 11 films with polarised IR spectroscopy using the amide A (N-H

30

stretching) and amide I (carbonyl stretching) bands. Butterfly-shaped hysteresis loops were obtained from graphs of peak intensity versus applied electric field strength. Time-dependent studies of the absorption intensities show that both ordered and disordered species switch towards the electric field direction with the application of electric fields higher than the coercive field. Upon field removal, only the disordered species show orientation relaxation away from the field direction. Below the coercive field, neither species aligns with the field (231).

7.12.7 Laser-Induced Orientation The laser-induced anisotropy in thin films of cyanoazobenzene side-chain liquid crystalline polytetradecanedioates, -dodecanedioates, and -adipates selectively deuterated at different positions was investigated by FTIR. In polyesters with long main-chain spacing (tetradecanedioates and dodecanedioates), not only the light-sensitive azo chromophore, but also the main-chain methylene segment and to a small extent the flexible spacer are preferentially oriented perpendicular to the laser light polarisation. The extent of orientation increases with increasing spacer length. Rapid-scan FTIR analysis performed on line with laser irradiation reveals that the alignment of the aliphatic segments arises simultaneously with the chromophore orientation (143).

7.13 Time-Resolved Spectroscopy Time-resolved IR spectroscopy is an extremely valuable tool to investigate the structural details of molecular changes incurred by a polymer under the influence of an external perturbation. The elucidation of the transient molecular changes during polymer deformation is an important issue in polymer processing. The ability to monitor and model mechanical drawing and relaxation processes benefits product quality. Time-resolved FTIR is used to study the structure and dynamics of ferroelectric liquid crystalline block copolymers. From analysis of the dynamic dichroism of the FTIR spectra, it was concluded that the components in the PS microphase are oriented randomly while the liquid crystalline groups form an ordered phase. The switching is of an electroclinic type, in which the tilt angle and the mesogenic motion increase with temperature, especially if the PS block is heated above Tg. The orientation of the liquid crystalline block after

Infrared and Raman Spectroscopy of Polymers

heating to the isotropic phase is completely restored due to the memory effect (i.e., reversible behaviour) of the polymer microstructure (101).

maximum. The chain ends of broken molecules recoil by trans-to-gauche transitions. Local stress accumulation will lead eventually to yarn rupture (320).

Time-resolved FTIR spectroscopy measurements were performed under isothermal crystallisation conditions to clarify the origin of the cocrystallisation and phase segregation phenomena observed for a series of PE blends between the deuterated and hydrogenated species, The degree of undercooling or the temperature jump depth (i.e., the size of the temperature drop) from the molten state to the isothermal crystallisation temperature was controlled (96).

The molecular orientation of the epoxy networks was investigated using rheooptical FTIR spectroscopy and uniaxial deformation was carried out above and below the Tg. The effects of diol chain length and molar ratio on the mechanical properties and orientation parameter were discussed (79).

7.14 Rheooptical FTIR Spectroscopy

Rheooptical FTIR spectra of a thermoplastic polyester urethane and Nylon 6 films were recorded under a varying sinusoidal strain. The large bipolar bands in the dichroic in-phase spectra, caused by large frequency shifts of the original monopolar absorption bands, were ascribed to hydrogen bonds (102).

IR spectroscopy can be coupled with the polarisation modulation technique in order to characterise the molecular orientation in polymer films. A computercontrolled variable-temperature stretching machine is used, which allows monitoring of vibrational spectra and stress-strain diagrams during deformation of polymer films up to 523 K (355). Polarisation modulation improves the SNR and minimises errors generated by repositioning the sample or the polariser for a second measurement. This technique is capable of measuring small dichroic effects with high sensitivity, even for very small sample draw ratios (291). Phase-locked electronics are used to record the dynamic IR spectral change in-phase and out of phase with the applied mechanical field. The method provides insight to the response to the external stress on the molecular and submolecular scale. Rheooptical FTIR spectroscopy is one of the few techniques providing data on the crystallisation, orientation and conformational changes of a polymer during mechanical treatment (83). Two dimensional correlation analysis is utilised to enhance the information derived from the vibrational spectroscopic data. The IR rheooptical technique was applied to study the molecular processes that take place along the stress-strain curve of PET yarns. The results indicate that the first modulus maximum marks the breakdown of the amorphous entanglement network and the start of molecular uncoiling by gauche-to-trans transitions. In addition, stress develops on the crystals and particularly on tie molecules with a short contour length in the amorphous domains. Ultimately, molecular fracture of taut-tie molecules (extended chains of polymers between crystals) causes the modulus to pass through a second

For PS/poly(vinyl methyl ether) blends, the addition of poly(vinyl methyl ether) to the blend increases the orientation of the PS chains during the stretching (92).

7.15 Two-Dimensional IR (2D-IR) Spectroscopy The general experimental approach in 2D-spectroscopy involves the application of an external perturbation that can selectively excite various chemical components of a given system. The excitation and subsequent relaxation processes, which are manifested by changes in peak intensities, shifts in spectral frequencies and variations in band shape, are monitored by a given spectroscopic probe. Two-dimensional-IR spectroscopy is a technique where the spectral intensity is plotted as a function of two independent spectral variables, e.g., frequency. The two orthogonal axes of independent spectral variables define a 2D spectral plane, and the spectral intensity may be plotted along the third axis. This approach can be used for probing the relationships between the molecular motions in IR spectroscopy. Two-dimensional-IR spectroscopy provides information that cannot be obtained by normal IR spectroscopy. Two-dimensional-IR can aid in the interpretation of complex spectra, especially with the broad overlapped peaks commonly encountered with polymers. The advantage of this method is the ability to separate overlapping bands and investigate the time sequence of certain spectral events (a.34). The power of the 2D-IR spectroscopy approach results primarily from an enhancement of the spectral

31

Infrared and Raman Spectroscopy of Polymers

resolution that has a physical origin. This effect relies on the dissimilarity between the responses of various functionalities absorbing at distinct frequencies. One can also make band assignments between IR bands and bands in NIR and Raman spectra. Two-dimensional-IR spectroscopy requires a series of perturbation-dependent spectra. The types of physical perturbations probed with this technique include: mechanical stress, applied potential, temperature, pressure, concentration and composition (a.35). In 2D-IR spectroscopy, the sample is perturbed externally to induce time-dependent fluctuations of the IR signal. The external perturbation can be any perturbation source that can excite chemical species in the system, including mechanical, optical, electrical, magnetic, chemical, thermal and acoustic perturbations. The reorientation of each functional group in the sample with a unique rate, extent, and direction produces resolvable fluctuations in the dynamic IR intensities. The changes are recorded in the dynamic spectra in the form of variation in the intensities, shifts of spectral band positions and changes in the shape of peaks. Generalised 2D spectroscopy can handle spectral fluctuations as an arbitrary function of time or of any other physical variables such as temperature, pressure, concentration and composition. Generalised 2D spectra emphasise spectral features not readily observable in conventional 1D spectra. It helps to probe the specific order of certain spectral events taking place with the development of a controlling physical variable. The generalised 2D approach is a qualitative method only; one can interpret only positions and signs of correlation peaks. The absolute magnitude of these peaks cannot be directly interpreted since they include information on both the amplitude and phase changes at two different frequencies (a.36).

Polyester-based PU elastomers contain hard and soft domains. It is desirable to characterise the molecular level interactions giving rise to the two domains, and to use this information to monitor chemical changes. The 2D correlation method provides a means by which the spectral information arising from the two domains can be resolved using thermal perturbations (95). Two-dimensional-IR spectra of glassy atactic PS reveal that while the main-chain backbone reorients in the direction of applied strain, there also exist highly localised reorientational motions of phenyl side groups occurring independently of the main-chain realignment. This localised submolecular distortion is not observed at temperatures well above the glass transition (107). Two-dimensional-IR spectra were used to study the orientation and the mobility of a ferroelectric liquid crystal dimer during switching by an electric field. The detailed mutual arrangements of different molecular segments (poly(siloxane), poly(methylene) chain, polysiloxane chain) in a smectic C phase were derived from the static spectra. Temperature and electric field strength dependencies of the mobility of these segments were established (163). A 2D-IR spectroscopic study on dissociation and hydrogen bonds of Nylon 12 over a temperature range of 30-150 °C showed gradual weakening of inter- and intramolecular associative interactions and a decrease of local order leading to the eventual fusion. (167). The asynchronous 2D-NIR spectra indicate that the amide groups with a free carbonyl oxygen appear first, and then unassociated free amide and amide with free NH follow as the temperature is increased (174).

A 2D experiment can be carried out using a conventional spectrometer by introducing a relatively slow external perturbation applied to the system of interest. In a typical 2D experiment, a series of perturbation-induced dynamic spectra are collected in some sequential order. Such a set of spectra may be readily manipulated mathematically, with the use of a simple scheme of correlation analysis to yield the desired 2D correlation spectra.

Two-dimensional-IR spectroscopy was used to study the N-H stretching and amide I/amide II region of meltcrystallised Nylon 11 thin films on Teflon substrates. The samples were mechanically oscillated at a frequency of 11 Hz. The dynamic spectra indicated that the N-H stretching region splits into two peaks. Analysis of 2D cross plots between the N-H stretching region and the amide I/amide II region showed that the prominent peak in the N-H stretching region (about 3300 cm-1) was similar in morphological character to the ordered peak of the amide I region. The amide II region resolved into two ordered and one disordered peak (254).

Two-dimensional NIR spectroscopy has been used for studies on the composition-dependent spectral variations in EVA copolymers. As a result, additional assignments of bands were made to ethylene units in amorphous, disordered, and orthorhombic crystalline phases (73).

Two-dimensional-IR spectroscopy involving mechanical excitation has been employed to study the mechanical relaxation phenomena in an acrylonitrilebutadiene-styrene terpolymer (ABS) sample. The study revealed detailed information regarding the molecular

32

Infrared and Raman Spectroscopy of Polymers

segments involved in macroscopic mechanical relaxation. From the temperature dependence of the dynamic signals it is corroborated that in the ABS sample the polybutadiene rubber relaxes entirely independently from the styrene-acrylonitrile copolymer (SAN) matrix, and thus is present as a separate phase in the material (169). A 2D-IR spectroscopic analysis on the dynamic spectra indicates that neat LDPE is comprised of three regions: an ordered crystalline region, a disordered liquid-like region, and a crystal/amorphous interfacial region. The 1468 cm-1 peak in the methylene bending region is assigned to the all-trans structures which primarily reside in the interfacial region. A variety of LDPE samples with different additives were used in order to determine how the additives influence the dynamic mechanical properties of each morphological phase LPDE. It is found that talc associates with the crystallites, EVA is distributed in all three morphological phases of the LDPE, and pyrene is associated only with the non-crystalline regions (218). Two-dimensional-IR spectroscopic analysis was used to monitor the submolecular orientational responses of the components of a semicrystalline 50/50 blend of LDPE with perdeuterated HDPE to a small amplitude, uniaxial, 23.47 Hz, sinusoidal mechanical strain. Analysis of the data indicated that the crystalline parts of the two components reorient at different rates, with the functional groups of the high density portion reorienting faster, in general, than those of the LDPE in response to the mechanical strain (316). FT-Raman spectra were determined for atactic PS, poly(2,6-dimethyl-1,4-phenylene ether) (PPE) and their blends. Composition-dependent spectral variations of the blends were analysed using generalised 2-D correlation spectroscopy to study the conformational changes and blend interactions. The 2D synchronous correlation analysis was able to discriminate between the bands of PS and those of PPE, and was able to detect bands that were not readily identifiable in 1D spectra. The main chain conformation of PS undergoes a drastic change on blending with PPE (57).

7.16 Recycling of Polymers One of the main causes of the high costs of recycling is sorting. It is essential to separate collected postconsumer waste in order to obtain plastics of one single type to feed the recycling process. The addition of chemical additives and new granular plastics can

only be done efficiently with the knowledge of all relevant physical and chemical properties of the collected basic material. As physical methods are not sufficient, the identification method has to monitor structural or molecular properties of the polymers. The NIR spectral range (700 to 2500 nm) allows the monitoring of structural or molecular properties of the plastic articles under investigation for recycling. The reduced absorption in the NIR allows registration of spectra of bulky plastics of practical interest in recycling. For fast scanning of the wavelength region of 1000 to 2200 nm, spectrometers based on AOTFs with a scan speed of 1000 nm/ms are applied to identify the plastics in mass consumer products and household wastes (206). On-line spectroscopic imaging requires high-speed sensors and short image processing steps. An optical instrument consisting of a high-throughput NIR spectrograph with an indium, gallium, arsenic (InGaAs)-array detector and specially designed collection optics has been used to record spectra from post-consumer packages located on an industrial conveyor belt (157). As these imaging systems generate large amounts of data, multivariate statistical techniques are required to extract the important information from the multidimensional spectroscopic images (77). This measuring technique is both economic and suitable for industrial environments, at least for certain waste fractions (household plastics, hollow articles, engineering plastics). The visual distinction between the spectra is demonstrated by aid of principal component analysis (PCA) plots. A fuzzy neural network further classifies the spectra. The method is assessed to be suitable for on-line identification under industrial conditions. A spectroscopic NIR imaging system, using a FPA detector, has been developed for remote and on-line measurements on a macroscopic scale. Multivariate statistical techniques are required to extract the important information from the multidimensional spectroscopic images. These techniques include PCA and linear discriminant analysis for supervised classification of spectroscopic image data (178). A NIR spectrometer system has been described based on optical fibres for absorption and reflexion measurements, an AOTF and a transputer system. It is able to detect 1,000 spectra per second and to identify 20 pieces per second (209). The identification system was implemented and tested for a real-world application of plastic identification in municipal solid waste.

33

Infrared and Raman Spectroscopy of Polymers

Automated sorting of post-consumer plastic waste was achieved using a combination of fixed-filter NIR and neural network data analysis. Rapid and reliable identification of polymers can be made. The effectiveness of the method was demonstrated for sorting PET, HDPE, and PVC (261). The composition of recycled HDPE/virgin PP blends prepared in a single-screw extruder have been monitored in-line at three different points by NIR (247). The suitability of Raman spectroscopy for computerised classification of post-consumer plastics was evaluated. Plastics investigated were PET, PP, PS, PVC, HDPE and LDPE. It was found that Raman spectroscopy could be used to identify both HDPE and LDPE (81). The composition of a polymeric material is of interest throughout its useful life from process stream to product fabrication, and finally to post-consumer recycling. It is desirable to know not only what types of materials are present, but also their relative concentrations. In many cases, Raman spectroscopy can provide a quick, convenient and relatively inexpensive alternative conventional analytical method for performing these types of determinations (266).

7.17 Depth Profiling from Surfaces and Interfaces 7.17.1 Optical Depth Profiling Using ATR-FTIR Spectroscopy ATR-FTIR spectroscopy is an optical depth profiling method in which a concentration or structural gradient is probed near the surface of a material, such as an adhesive, sealant or coating. Recently, a number of improvements have been made in the method (192). In one method, by varying the thickness of a barrier film, different effective penetration depths are achieved (194). ATR-FTIR spectra of a laminate (PMMA/PVAL) were presented at different base layer thicknesses and different angles of incidence on a zinc selenide substrate. By varying the thickness of the PMMA barrier film, different effective penetration depths in the PVAL were achieved to detect interfacial interactions (245). In another method, two internal reflection elements, Ge and KRS-5, with an angle of incidence of 45 degrees, were used to obtain the depth profiles of the crystallinity of PP sheets from the surface to the bulk (204).

34

A metal overlayer ATR-FTIR technique which markedly enhances the SNR of monolayer and submonolayer film spectra has been described. The metals investigated were gold and aluminium, with a substrate of polyether-urethane elastomer (375). The use of silver films under ATR geometry has improved the detection limit of the surface layer on polymer films. An enhancement factor of 10 and 2 is reported for polydimethylsiloxane and polycarbonate respectively, compared to the conventional ATR technique (362). ATR-FTIR was used to determine the concentration of a chemical additive (cationic polyacrylamide resin) within a pulp fibre. The depth distribution of the additive was determined by sputter etching the fibre surface. The obtained profile was compared qualitatively with that obtained by the variable-angle ATR-FTIR depth profiling method. Most of the additive was located at the surface, with some distributed within the fibre (137).

7.17.2 Depth Profiling Using Photoacoustic IR Spectroscopy Photoacoustic spectroscopy involves the modulation of IR radiation at a frequency in the acoustic range. The radiation strikes a sample and is subsequently turned into heat energy by nonradiative deexcitation processes (i.e., excitation is loss by thermal motion and not by the emission of energy). Heat-generated thermal waves then propagate to the sample surface and facilitate the rapid expansion and contraction of a carrier gas. A microphone is used to sense the change in pressure in the enclosed cell. As only photoacoustic spectroscopic (PAS) signals generated within the thermal diffusion length are detected, the method can be used to discriminate between the surface and underlying layers of solid materials. PAS is useful for probing penetration of about 1 x 10-5 m. The depth of detection is dependent on the thermal and optical properties of the sample. Sampling depth in PAS is determined by the mirror velocity of the interferometer. Low optical velocities will result in PAS signals from deep within the sample, while high optical velocities will allow thermal diffusion from the surface regions. The sampling depth increases (by a factor of about three across the wavenumber range 400-4000 cm-1) with decreasing wavenumber. In PAS, the time-resolved photoacoustic response to sinusoidally modulated incident source radiation has a phase delay which depends on the depth in the sample

Infrared and Raman Spectroscopy of Polymers

from which the photoacoustic response originates. Use of a stepscanning interferometer circumvents the difficulties arising when a single chopping frequency is used for all wavelengths (a chopper is used to interpret the beam at a single frequency). Step-scan photoacoustic FTIR experiments can be used to collect information from selectable and constant depths from the sample surface. FTIR step-scan photoacoustic spectroscopy was used to study the composition of thermoplastic olefin films, as a function of depth below the surface. Experiments were completed at various modulation frequencies, enabling a stratification model to be developed. The uppermost layer (0-3 μm) showed large changes in talc and PP concentration, while the layer below showed a significant decrease in both the phases. In the third layer (6-9 μm), all three phases showed the maximum values. In the fourth layer (9-12 μm), the talc concentration reduced, whilst concentrations of elastomeric copolymer of ethylene and propylene (EPR) and PP were observed, decreasing with depth (44). FTIR photoacoustic spectroscopy was used for the study of the adsorption of poly(n-butyl methacrylate) from cyclohexane, benzene and carbon tetrachloride onto alumina. The efficiency of adsorption increased in the order cyclohexane, carbon tetrachloride, benzene, while methanol and tetrahydrofuran showed negative adsorption. Poly(n-butyl methacrylate) had a negative temperature coefficient of adsorption (126). A step-scan FTIR photoacoustic phase-resolved technique was used to depth profile micrometre-thick layered plasma polymers (171). Migration and concentration levels of sodium dioctylsulfosuccinate (SDOSS) surfactant molecules in silicone-modified 50%/50% styrene/butyl acrylate latex were detected at the film-substrate and film-air interfaces in mono- and double-layered films. The SDOSS content was shown to be influenced by the presence of trimethoxysilyl propylmethacrylate siloxane (202). Injection-moulded PP plates, with and without titanium dioxide pigment, were irradiated in a medium-accelerated photoageing device to the equivalent of 1 year of outdoor exposure. Photoacoustic FTIR spectra of photooxidised samples were analysed. The oxidation profiles monitored were shown to arise from oxygen diffusion limitation and also from the heterogeneous absorption of light by the titanium dioxide-pigmented samples (336).

Dimensionally dependent changes are encountered in PVC weathering processes. Changes are observed during outdoor photodegradation of PVC siding capstock (paint without additives such as pigments) formulations, as a function of exposure time and titanium dioxide level. Profiles through the thickness dimension were analysed to identify degradation species and depth distribution (76).

7.17.3 Depth Profiling Using Confocal Raman Microspectroscopy The depth and surface distribution of the PS grafts, crosslinker, and the sulfonation efficiency were studied using confocal Raman microspectroscopy. Highly grafted samples had a homogeneous distribution of grafts and homogeneous sulfonation, whereas uneven graft distributions were observed in samples with low and intermediate degrees of grafting. The crosslinker concentration in the interior of the film was approximately 50% of the surface concentration (61). Confocal Raman microscopy was used for the investigation of variations in crosslinking with depth in thicknesses of up to 0.5 mm in UV-cured coatings. Variations of curing with depth in pigment formulations, in thicknesses of up to 30 μm, were observed (62). Confocal Raman spectroscopy was used to examine depth or lateral profiles of the crosslinking process (e.g., the reaction progress) in radiation curable coatings with a resolution of approximately 1 μm3. The potential of confocal Raman microscopy is demonstrated for the problems of the inhibition of the radical polymerisation reaction by oxygen, the limited polymerisation reaction in deep layers due to the restricted penetration of UV light (Lambert-Beer), the reaction in pigmented coatings and the distribution of UV stabilisers interacting with the UV curing process (118). Confocal Raman microprobe spectroscopy was used to characterise polyaniline/poly(N-vinyl carbazole), polypyrrole/poly(N-vinyl carbazole) and polypyrrole/ polyaniline films (or reverse order of each pair in the films). Two types of film were observed, depending on the conditions. Either the second polymer was incorporated into the initially coated layer or a doublelayer film with a well-defined interface was formed. Electrolysis of pyrrole and aniline monomer mixtures gave films rich in pyrrole when the pyrrole:aniline molar ratios were greater than 0.12. However, polymerisation of N-vinyl carbazole and pyrrole monomer mixtures gave only polypyrrole over a wide range of molar ratios (121).

35

Infrared and Raman Spectroscopy of Polymers

Confocal Raman microspectroscopy was used to measure local compositions along a direction that was perpendicular to the original interface. Composition profiles generated by interdiffusion in the concentrated regime between polyphenylene oxide-polystyrene blend pairs were determined (128). Depth profiling was carried out using confocal Raman microspectroscopy to study PAN/PVAL and PAN/PA laminates. The laminates were annealed at 65, 75 and 90 °C. It was demonstrated that the degree of hydrogen bonding interaction between the nitrile and alcohol groups near the interfacial region changes between laminates annealed at different temperatures. For comparison, Raman mapping of a PAN-PVAL blend was used to study the interactions between the polymers in this (disordered) system (147). Confocal Raman microspectroscopy was used to characterise the chemical composition of clearcoats in paint systems. Weathered and unweathered samples of isolated acrylic/melamine and acrylic/urethane clearcoats, polyester urethane clearcoats in weathered and unweathered samples of a complete paint system on plastic, and UV light cured acrylic clearcoats on polycarbonate substrates were studied (149). It was demonstrated that confocal Raman microspectroscopy can be successfully used to study the hydrogen bonding interactions between the ester and alcohol groups near the interfacial region. Various laminates have been studied and it is demonstrated that PMMA layers with lower molecular weight show a greater degree of interpenetration for a given annealing time (225).

7.18 FTIR Microspectroscopy FTIR microspectroscopy, coupled with mapping techniques, is an effective method for evaluating dimensionally-dependent changes. The method is based on the specificity of the IR spectrum and the dimensional resolution of the microscope. The keys to the successful use of FTIR microscopy are experience in sample preparation, an understanding of light microscopy, and ingenuity in defining solutions. The fatigue of NR and styrene-butadiene rubber (SBR) is an enormous industrial problem, as important mechanical properties of these materials deteriorate quickly when stressed. Although fatigue may describe the deterioration of certain material properties, it is generally believed that the term also describes failure

36

by cracking. In fact, abrasive wear is due to the cumulative growth of cracks by tearing under repetitive loading. Therefore, the analysis and characterisation of cracks in NR are crucial to the development of material with improved fracture resistant properties. Several spectroscopic methods are available for characterising the crack tip region of the rubber on the molecular scale; FTIR microspectroscopy has been used for this purpose (91). FTIR microspectroscopy was applied for the characterisation of compositional heterogeneity of a polymer blend. For a polymer blend prepared by mixing PP and polycarbonate, the spatially specific compositional heterogeneity could be easily identified (106). Mapping the phases of PVAL and PVA blends was accomplished using FTIR microspectroscopy. The dimensions, shapes, and distributions of the domains are dependent on the initial composition of the polymeric mixtures in solution. Specific interactions between both homopolymers were observed (129). Polyvinylidene fluoride (PVDF) samples, obtained by casting from tetrahydrofuran (THF) solutions and submitted to various thermal treatments, were examined by FTIR microspectroscopy. The analysis permitted examination of microdomains of samples of different morphological characteristics and an indication of the polymorphism of PVDF is obtained (213). FTIR microspectroscopy was used to investigate the drying of water-based acrylic polymer coatings on an aluminised substrate. Changes in the absorbance peak heights were monitored as an indication of the remaining water content. The effects on drying of humidity, solids content, coating thickness and the presence of coalescing agents were studied. Coalescing agents were found to increase drying time while aiding film formation. Drying time decreased with increasing solids content and increased with increasing coating thickness. As expected, relative humidity was found to have an important effect on the drying process (246). The interphase in PE fibre/epoxy resin matrix composites was studied by FTIR microspectroscopy using a set up for investigation of the matrix as close to the fibre as a few microns or less. It was shown that moisture present on the fibre surface could influence the polymerisation reaction of the epoxy/anhydride matrix in an irreversible manner (249). Model composites of Kevlar-49 and D-glass fibre/ epoxy systems were analysed using FTIR micro-

Infrared and Raman Spectroscopy of Polymers

spectroscopy. The interphase and specific fibre-matrix interactions of the fibre-reinforced composites were characterised. The surfaces of both Kevlar-49 and Dglass fibres were found to affect the curing process in composite samples significantly. The epoxy was found to cure at an accelerated rate at the surface of these fibres indicating strong interaction between the fibres and the matrices. Using FTIR microspectroscopy, these interactions were found to be preferential segregation of the epoxy on the Kevlar surface. It was also determined that the amine group of the Kevlar fibre acted to catalyse the curing process (286). FTIR mapping was used to study vinyl siding. Particular attention was paid to the determination, in single mapping experiments, of the compositional changes associated with capstock to substrate transition and to evaluation of the degradation species and level observed during weathering exposure throughout the thickness of the siding panel (153). A combination of cryomicrotomy and FTIR microscopy was used to investigate chemical changes in unstrained sheets of PU caused by biodegradation (18 month subcutaneous ovine implant). Cryomicrotomy was used to obtain thin sections from the surface into the bulk, parallel to the plane of the surface. FTIR microscopy was then used to detect chemical changes (156). The effect of mechanical deformation on a UV-cured urethane-acrylate polymer and on a silicon carbide/ urethane-acrylate model composite was studied by FTIR microspectroscopy. This technique was used for the first time to measure the width of the interfacial zone beyond which the fibre has no influence on the matrix (161). FTIR microspectroscopy has proved useful in characterising contaminants as small as 5 x 10-5 m in diameter in resins and cured films as well as characterising cured film surfaces (191). Glass fibre strand was treated with gammamethacryloxypropyltrimethoxysilane as a coupling agent and used to reinforce a vinylester resin. The interface was studied by FTIR spectroscopy and showed that the silane was able to migrate into the resin and influence curing at a distance (200 μm) greater than the thickness of the interphase (328). IR microspectroscopy was used to study the cell membranes of a flexible PU foam and correlations were made of absorbance values of methyl signals with absolute thicknesses calculated from the interference patterns observed in the spectra (333).

A comparison is made of the polymer and liquid crystal droplet regions within polymer-dispersed liquid crystal films using FTIR microspectroscopy. IR functional group images of a droplet showed characteristic textures corresponding to the visual images of the same droplet. The textures in the IR images changed with IR polarisation and with an applied electric field. Hysteresis was observed in the IR region as a function of voltage and temperature (334). IR microspectroscopy was used to generate functional group images of liquid crystal (E7) droplets dispersed in poly-n-butyl methacrylate (PBMA). The spatial concentration fluctuations that occurred within the system were studied as a function of time. This approach was possible because spectral information could be obtained by focusing on regions of the order of tens of micrometres. The peak intensities were used as a measure of concentration of the components. The amount of liquid crystal dissolved in the polymer matrix determined the extent to which the polymer was plasticised, which in turn affected the shape and size of the droplets. The growth of the domains at any temperature was also determined by whether the system was maintained above or below the Tg of the matrix. It was observed that the growth of the droplets followed temporal power laws (i.e., time raised to a power of ~θn). The spatially resolved spectroscopic images provided valuable insights into the phase separation process and the formation of microdroplets of E7 in PBMA (280).

7.19 FTIR Imaging FTIR spectroscopic imaging microscopy is a technique in which instrumentation is designed about an InSb multichannel IR array detector, FPA detector and a variable-bandpass dielectric filter. The system may be configured for either macroscopic or microscopic applications and high-fidelity, chemically specific images may be acquired in real time. The functioning of the imaging microscope is demonstrated with samples including PS microspheres, preparation of lipids and an amino acid embedded in KBr disks, and a tissue sample derived from a coronal slice of a monkey cerebellum (271). The FTIR imaging method was extended to the realtime acquisition of images from systems varying with time. Emphasis is given to the monitoring of the diffusion of a low molecular weight liquid crystal pentylcyanobiphenyl into a solid polybutyl methacrylate film (136).

37

Infrared and Raman Spectroscopy of Polymers

An imaging spectrometer made measurements of the visible and NIR absorption spectra of EVA copolymers. The NIR spectral images obtained clearly indicated that the EVA copolymers exhibited a high degree of chemical inhomogeneity (105). FTIR imaging is a powerful technique that can be used to obtain spatially resolved chemical information from a large sample area in a relatively short time. However, temporal resolution of fast FTIR imaging is limited by rapid loss of data quality due to increased noise with faster image acquisition. The application of the proposed schemes allows for improved SNR characteristics in the resulting data. These schemes are tested by monitoring the dissolution of a polymer film (poly (alpha-methyl styrene)) by a low molecular weight solvent (methyl isobutyl ketone (MIBK)). A total acquisition time of about 100 s is achieved, allowing the dissolution process to be monitored by using image acquisitions separated by 3 minutes. Low noise concentration profiles, linear solvent penetration rate and polymer dissolution rate are measured. This result represents an order of magnitude improvement over untreated data (47). The FTIR imaging method was extended to the realtime acquisition of images from systems varying with time. Emphasis is given to the monitoring of the diffusion of a low molecular weight liquid crystal pentylcyanobiphenyl into a solid polybutyl methacrylate film (136). Fast FTIR imaging was used to study the distribution of chemical species and the degree of orientation in semi-crystalline systems. The systems investigated were PEG and blends of PEG with PEO, PMMA or PVA. The technique was shown to be useful for determining the distribution of species with different molecular weights and for determining the degree of segregation of the different blend components. Using an IR polariser, the degree of orientation was determined in the systems by generating spatially resolved dichroic ratio images (52). FTIR imaging, combined with statistical methods, was shown to be a valuable tool for determining phase composition in multiphase systems. A method for reducing liquid crystal solubility in production of polymer dispersed liquid crystals (PDLC) was developed which involved cooling a homogeneous liquid crystal/precursor matrix into the two-phase regime, followed by fast matrix polymerisation. The proposed procedure was tested by using a well-studied PDLC system, NOA65 (a UV-curable optical adhesive) and E7 (a mixture of cyanobiphenyls). Liquid crystal

38

remaining dissolved in the matrix was sharply reduced by this method. Residual solubility of the matrix material in liquid crystal domains was also decreased. While maintaining the same phase composition, the method also allowed dispersion size to be tailored according to needs as opposed to the invariable correlation between droplet size, solubility and polymerisation rate inherent in the classical polymerisation-induced phase separation methods. This general methodology could be usefully applied to other systems (88).

7.20 Raman Microimaging The incorporation of high-resolution optics in a Raman spectrometer allows sampling from areas of less than 1 x 10-6 m in diameter. The addition of a confocal microscope improves the axial resolution to 2 x 10 -6 m. Those developments, along with the introduction of notch filters and holographic transmission gratings, allow the reduction of the acquisition time of Raman spectra from minutes to seconds. The fast data collection combined with the high lateral and vertical resolutions makes possible scanning experiments in which the specimen is advanced in 1 x 10-6 m size steps. Analysis of the spectra provides information on the spatial composition of the sample (139). Two alternative methods of Raman imaging via global illumination and via point illumination in combination with confocal light collection can be applied to the study of heterogeneous polymer systems (205). The effects of spectrometer slit width, spatial resolution and the number of spectral variables of Raman line-images were studied. Depth of penetration and SNR considerations dominated the proper selection of slit width for the sample of PS spheres (10 μm diameter) embedded in an epoxy resin matrix. With the use of different microscope objectives to analyse the same sample region, the higher-magnification objective gave better results, probably due merely to the larger number of spectra processed (222). Raman microimaging is used to estimate the effect of the silica filler on phase separation in binary polymer blends composed of brominated poly(isobutylene-copara-methyl) styrene (BIMS) and butyl rubber (IIR). The domain sizes, relative concentration of polymer components within domains, and distribution of particulate silica filler and zinc stearate curative are characterised for blends of different compositions and history of ageing treatments. The presence of increased concentrations of precipitated silica results in better

Infrared and Raman Spectroscopy of Polymers

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D.A. Long, Raman Spectroscopy, McGrawHill, New York, NY, USA, 1977.

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D.B. Chase and J.F. Rabolt, Ed., Fourier Transform Raman Spectroscopy, Academic Press, Orlando, FL, USA, 1994.

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E.G. Bucher and J.W. Caranhan, Applied Spectroscopy, 1999, 53, 603.

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J.L. Koenig, Spectroscopy of Polymers, 2nd Edition, Elsevier, Amsterdam, the Netherlands, 1999, 147.

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polymer morphology since domain sizes are reduced. Increased temperature treatment also decreases domain sizes up to about 150 °C, but treatment at 200 °C appears to induce separation of the elastomer components. Silica is usually found near the centres of the BIMS domains. There is little difference in silica distribution before and after curing (33). Using micro-Raman imaging three blends consisting of PP/PE/EPR copolymer, PBT/polycarbonate/LDPE, and SAN copolymer/styrene-maleic anhydride copolymer/polydimethylphenylene oxide were studied with regard to compositional and morphological heterogeneities (221).

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P.C. Painter, M.M. Coleman and J.L. Koenig, The Theory of Vibrational Spectroscopy and its Application to Polymeric Materials, John Wiley & Sons, Inc., New York, NY, USA, 1982. D. Lin-Vien, N. Colthup, W.G. Fateley and J.G. Grasselli, The Handbook of Infrared and Raman Characteristic Frequencies of Organic Molecules, Academic Press, San Diego, CA, USA, 1991. B.G. Osborne, T. Fearn and P.H. Hindle, Practical NIR Spectroscopy, Longman Scientific and Technical Publishers, Harlow, UK, 1993.

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Infrared and Raman Spectroscopy of Polymers

Abbreviations ABS

Acrylonitrile-butadiene-styrene terpolymer

PBT

Polybutylene terephthalate

PCA

Principal component analysis

AC

Acid chloride

PDA

p-phenylene diamine

AIBN

Azobisisobutyronitrile

PDLC

Polymer dispersed liquid crystal

AOTF

Acousto-optic tunable filter

PDMS

Polydimethyl siloxane

ATR

Attenuated total reflection

PDPE

Low density polyethylene

BIMS

Brominated poly(isobutylene-copara methyl) styrene

PE

Polyethylene

PEG

Polyethylene glycol

BPDA

3´,3´,4,4´-biphenyltetracarboxylic dianhydride

PEI

Polyethyleneimine

CCD

Charge collection detector

PEN

Poly(ethylene naphthalate)

CHMI

N-cyclohexylmaleimide

PEO

Polyethylene oxide

CHPS

Cyclohexa(p-phenylene sulfide)

PET

Polyethylene terephthalate

COF

Acid fluoride group

PHEMA

Poly(2-hydroxyethyl methacrylate)

COOH

Carboxylic acid group

PLS

Partial least squares

DRIFT

Diffuse reflectance FTIR

PLSR

Partial least squares regression

ENR

Epoxidised natural rubber

PMAA

Polymethacrylic acid

EPDM

Ethylene-propylene-diene terpolymer

PMMA

Polymethyl methacrylate

PNIPAAM

Poly(N-isopropylacrylamide)

EPR

Ethylene-propylene copolymer

PP

Polypropylene

EVA

Ethylene-vinyl acetate

PPE

Poly(2,6-dimethyl-1,4-phenylene ether)

FPA

Focal plane array

PPMS

Poly-p-methylstyrene

FTIR

Fourier transform infrared

PPO

Polypropylene oxide

GMA

Glycidyl methacrylate

PPS

Poly(p-phenylene sulfide)

GTP

Group transfer polymerisation

PS

Polystyrene

HDPE

High density polyethylene

PTFE

Polytetrafluoroethylene

HPLC-FTIR

High performance liquid chromatography - FTIR

PU

Polyurethane

IIR

Butyl rubber

PVA

Polyvinyl alcohol

IR

Infrared

PVAL

Polyvinyl alcohol

LCST

Lower critical solution temperature

PVC

Polyvinyl chloride

MIBK

Methyl isobutyl ketone

PVDF

Polyvinylidene fluoride

MMA

Methyl methacrylate

SDOSS

Sodium dioctylsulfosuccinate

NIR

Near infrared

SERS

Surface-enhanced Raman spectroscopy

NMR

Nuclear magnetic resonance

SFE/FTIR

Supercritical fluid extraction/FTIR

NR

Natural rubber

SNR

Signal to noise ratio

PA

Polyamide

Tg

Glass transition temperature

PAA

Polyacrylic acid

THF

Tetrahydrofuran

PAM-co-AA

Poly(acrylamide-co-acrylic acid)

TMPO-1

1,2-epoxy-2,4,4-trimethylpentane

PAN

Polyacrylonitrile

TPR

Terpene-phenol resins

PBI

Polyphenylene bibenzimidazole

UVRR

Ultraviolet Raman resonance

PBMA

Poly-n-butyl methacrylate

VA

Vinyl acetate

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Infrared and Raman Spectroscopy of Polymers

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References and Abstracts

References from the Rapra Abstracts Database Item 1 ACS Polymeric Materials Science and Engineering. Volume 75. Conference Proceedings. Orlando, FL., Fall 1996, p.106-107. RAMAN AND FTIR STUDIES OF THE EFFECTS OF DRAW RATIO AND SIDE CHAIN LENGTH ON THE MOLECULAR ORIENTATION OF POLYESTER FILMS Vlassopoulos D; Petekidis G; Vogiatzis G; Kamitsos E I; Yiannopoulos Y; Bruggeman A Crete,Institute of Electronic Structure & Laser; Patras,Institute of Chemical Engineering & High Temperature Processes; Foundation for Research and Technology Hellas; Athens,National Hellenic Research Foundation; TNO Plastics & Rubber Research Institute (ACS,Div.of Polymeric Materials Science & Engng.) Laser Raman and FTIR spectroscopy measurements were combined to determine the degree of molecular orientation in uniaxially oriented polyester films, as a function of the draw ratio, and so that the effects of side chain length can be further quantified. The measurement of molecular orientation in liquid crystalline polymers is of high importance because of its potential in obtaining ultra-high modulus materials. A significant degree of molecular orientation along the stretching direction was identified. 10 refs. USA

Accession no.806758 Item 2 Journal of Sol-Gel Science and Technology 19, Nos.1-3, Dec.2000, p.403-7 STRUCTURE OF HYBRID GELS BY DRIFT AND NMR SPECTROSCOPIES Fidalgo A; Nunes T G; Ilharco L M Lisbon,Instituto Superior Tecnico Hybrid inorganic-organic gels were prepared by the solgel process using tetraethoxysilane as precursor, mixed with a low concentration of polytetrahydrofuran, under acid catalysis. The hybrid xerogels were characterised by DRIFTS and solid state proton, carbon-13 and silicon-29 NMR spectroscopies. The diffuse reflectance IR (DRIFT) spectra indicated that the polymer was responsible for decreasing the number of free silanol groups in comparison with pure silica. Solid state NMR spectra revealed the types of silicate structures formed and the conditions for establishing chemical bonds between the two phases, which were responsible for the silica network flexibility. It was concluded that it was possible to design a hybrid gel with tailored properties, even at very low polymer concentration, by selecting the appropriate preparation route. 10 refs. (10th International Workshop on Glass and Ceramics,

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Hybrids and Nanocomposites from Gels, ‘Sol-Gel ‘99’, Yokohama, Japan, Sept.1999) EUROPEAN COMMUNITY; EUROPEAN UNION; PORTUGAL; WESTERN EUROPE

Accession no.805107 Item 3 ACS Polymeric Materials Science and Engineering. Volume 75. Conference Proceedings. Orlando, FL., Fall 1996, p.70-1. 012 ATR FT-IR SPECTROSCOPIC STUDIES OF MICROWAVE PLASMA REACTIONS OF IMIDAZOLE ON POLY(VINYL CHLORIDE) Schmitt B R; Kim H; Urban M W North Dakota State University (ACS,Div.of Polymeric Materials Science & Engng.) This work focuses on imidazole reactions to polyvinyl chloride (PVC), formation of reactive sites, reaction mechanisms, and quantitative analysis of the surface species at various depths. For quantitative surface analysis ATR FT-IR spectroscopy was used. For hot-pressed PVC, no imidazole reactions were detected on PVC surfaces under argon and oxygen microwave plasma conditions. Under oxygen microwave plasma conditions, however, newly formed CH2 linkages are detected, resulting from the C-Cl bond cleavages. In solvent-cast PVC, imidazole molecules react to PVC through a carbon-carbon double cleavage of imidazole, and the formation of the ester linkages between PVC and imidazole molecules. Quantitative analysis of imidazole reactions to solventcast PVC surfaces at various depths reveals that imidazole reactions take place within 0.8 microns from the surface. At surface depths of up to 1.2 microns, surface concentration of imidazole reacted to PVC declines from 0.37 x 10-6 mole/square centimetre to 0.17 x 10-6 mole/ square centimetre. 8 refs. USA

Accession no.803055 Item 4 ACS Polymeric Materials Science and Engineering. Volume 75. Conference Proceedings. Orlando, FL., Fall 1996, p.65-6. 012 POLYOLEFIN CHARACTERIZATION OF FTIR TRANSMISSION SPECTROSCOPY Blitz J P Eastern Illinois,University (ACS,Div.of Polymeric Materials Science & Engng.) FTIR spectroscopy was used to measure polyethylene and polypropylene isotacticity, specifically to provide data in the relatively narrow, industrially important high isotacticity range. The FTIR data reported in this range is correlated with both NMR and solvent extraction

43

References and Abstracts

measurements. The present work demonstrates the usefulness of ordinary transmission FTIR spectroscopy in obtaining qualitative and quantitative data concerning short chain branching in a variety of polyethylenes. It is possible to obtain quantitative isotacticity values of polypropylene by transmission FTIR spectroscopy. FTIR has particular advantages over NMR spectroscopy in terms of cost and ease of use. In many instances, FTIR can be utilised more readily than NMR. In other instances, more detailed structural information can still be provided by NMR than FTIR. 4 refs. USA

Accession no.803052 Item 5 ACS Polymeric Materials Science and Engineering. Volume 75. Conference Proceedings. Orlando, FL., Fall 1996, p.63-4. 012 SPECULAR REFLECTION FT-IR STUDIES OF THE CONFORMATIONAL BEHAVIOUR OF PET Cole K C; Guevremont J; Aiji A; Pellerin E; Dumoulin M M Canada,Industrial Materials Institute (ACS,Div.of Polymeric Materials Science & Engng.) The use of front surface specular reflection Fourier infrared spectroscopy was used to obtain information on molecular conformation and orientation at the surface of thick samples of drawn poly(ethylene terephthalate) (PETP). Reflectance spectra measured with polarisation parallel or perpendicular to the draw direction can be decomposed into refractive index and absorption index spectra, by means of the Kramers-Kronig transformation. The most interesting of the strong bands of PETP is the carbonyl band. A mechanism for the conformational changes that take place on drawing PETP is proposed in which planar states are energetically favoured, the barrier to rotation is sufficiently low to allow a high probability of non-planar states. Drawing at 80 degrees Celsius causes significant conversion of gauche to trans conformers in the glycol segments, but it does not appear to have an effect on the terephthalate groups. 12 refs. USA

Accession no.803051 Item 6 ACS Polymeric Materials Science and Engineering. Volume 75. Conference Proceedings. Orlando, FL., Fall 1996, p.43. 012 DETERMINING THE ORIENTATIONAL ORDER OF MEMBRANE-BOUND POLYPEPTIDES BY POLARIZED ATIR-FTIR Axelsen P H; Citra M J Pennsylvania,University (ACS,Div.of Polymeric Materials Science & Engng.) The orientational order of polypeptide helices can be characterised by polarised attenuated total internal

44

reflection Fourier transform infrared (PATIR-FTIR) spectroscopy. This requires an understanding of the evanescent electric field amplitudes, and these, the orientation of the vibrational transition moment relative to the helix axis. A number of expressions used for calculating evanescent electric field amplitudes in supported lipid membranes are discussed and their validity tested by measuring the infrared dichroism of polygamma-benzyl-L-glutamate and poly-beta-benzyl-Laspartate under conditions in which their conformation and molecular order is known. The results suggest that the aspartyl and glutamyl peptides display differing values for theta, despite similar amide absorption frequencies and band shapes. The results also indicate that the absorption intensities for these polymers in a lipid membrane are self-consistent only if it assumed the electric field amplitudes to be determined entirely by the refractive index of the bulk medium in which the crystal is immersed. USA

Accession no.803039 Item 7 ACS Polymeric Materials Science and Engineering. Volume 75. Conference Proceedings. Orlando, FL., Fall 1996, p.39-40. 012 HIGH-PRESSURE PHOTOACOUSTIC STEPSCAN FT-IR SPECTROSCOPY OF POLYMERS Pennington B D; Urban M W North Dakota State University (ACS,Div.of Polymeric Materials Science & Engng.) The basis for high pressure photoacoustic spectroscopy and the resulting enhancement of the photoacoustic signal is described. An experimental setup has been designed which enhances the photoacoustic signal response, which is attributed to the more efficient transfer of the photoacoustic signal from the analysed specimen to the microphone. In addition, phase analysis results can be derived from high pressure experiments in step-scan mode. The high pressure experiments were carried out using thermoplastic olefin (TPO), silanol terminated polydimethylsiloxane (PDMS), and polyimide. In all cases intensity enhancements were detected as pressure rises. A comparison of the pressure effect on the relative signal enhancement shows a less pronounced effect in the liquid polymer (PDMS) than for the solid samples (TPO or polyimide). This is because the distance from the sample to the cell window is inversely proportional to the photoacoustic signal intensity so that a rise in this distance parameter will result in a decreased photoacoustic response. As pressure is applied to a specimen, specific volume and inter-molecular distance change, resulting in a decrease in the physical dimensions of the sample, which results in the change in the photoacoustic signal intensity and the shift of the photoacoustic phase. 15 refs. USA

Accession no.803035

© Copyright 2001 Rapra Technology Limited

References and Abstracts

Item 8 ACS Polymeric Materials Science and Engineering. Volume 75. Conference Proceedings. Orlando, FL., Fall 1996, p.11. 012 QUANTITATIVE ASPECTS OF ATR AND PHOTOACOUSTIC STEP-SCAN FT-IR AND INTERFACIAL ANALYSIS OF POLYMERIC FILMS Urban M W North Dakota State University (ACS,Div.of Polymeric Materials Science & Engng.) There are significant implications arising from the ability of stratifying polymer surfaces and interfaces using attenuated total reflectance and photoacoustic step-scan Fourier transform infrared (FTIR) spectroscopy. Theoretical concepts and experimental methods involved in the stratification approach to polymer films are discussed. Quantitative analysis of interfacial regions in multi-layered polymers is given particular emphasis. The utilisation of ATR and SS PAS, together with the stratification multi-layer concept, enables depth-profiling experiments to be carried out on multi-layered polymer films. It also provides molecular level data relating to interfacial interactions between the layers. USA

Accession no.803018 Item 9 ACS Polymeric Materials Science and Engineering. Volume 75. Conference Proceedings. Orlando, FL., Fall 1996, p.11. 012 SURFACE-ENHANCED AND FOURIERTRANSFORM RAMAN SPECTROSCOPY OF POLYMERS Boerio F J; Zhao W W; Tsai Y M Cincinnati,University (ACS,Div.of Polymeric Materials Science & Engng.) In order to determine the interfacial and bulk structure of polymers surface-enhanced (SERS) and FourierTransform Raman spectroscopy were utilised. LangmuirBlodgett monolayers of PMDA/ODA polyimides were formed by transferring monolayers of the dimethylhexadecylamine salt of the polyamide acid onto silver island films. SERS spectra of 1- and 3-layer LB films of the salts were characterised by bands near 1400 and 1620 cm-1 that were related to carboxylate species and to a stretching mode of the benzene rings, respectively, New bands related to isoimide and imide groups appeared near 1695 and 1800 cm-1 when the films were imidised. Characterisation of the curing of a model rubber compound consisting of squalene (instead of natural rubber), initiators, sulphur, accelerators, adhesion promoters, anti-oxidants, and carbon black was achieved by using FT/Raman spectroscopy. Only one band, near 1670 cm-1, was observed between 1500 and 1700 cm-1 for short curing times. For longer curing times, new bands attributed to conjugated double bonds were observed near

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1646, 1640, 1628, 1600 and 1580 cm-1. Also, a new band related to polysulphidic crosslinks appeared near 210 cm1 after reaction for 15 minutes. After about 30 minutes the intensity of this band reached a maximum. A model for the curing reaction was developed from these observations. USA

Accession no.803017 Item 10 ACS Polymeric Materials Science and Engineering. Volume 75. Conference Proceedings. Orlando, FL., Fall 1996, p.8. 012 RAMAN SPECTROSCOPY AND CRYSTALLINE POLYMERS: THE POLYETHYLENES Mandelkern L; Rufina G A Institute of Molecular Biophysics; FAMU-FSU College of Engineering (ACS,Div.of Polymeric Materials Science & Engng.) An overview is given of some of the applications of Raman spectroscopy that lead to an understanding of the factors that determine the phase structure of crystalline, flexible chain polymers. Emphasis is given to the polyethylenes of different molecular architectures and their corresponding oligomers, the n-alkanes. The focus of the spectroscopic data is the internal mode and LAM spectral regions. In order to determine the crystallite thickness it is necessary to establish Young’s modulus and to evaluate the validity of the basic relation that is involved. This study illustrates the difficulty in determining the exact ordered sequence length for polyethylene and for folded n-alkanes and other oligomers and relates to the establishing of integral fold periods. For a system of stacked lamellae, an analysis of both the LAM and internal modes can give the thickness of the interfacial region. Data is presented which gives quantitative agreement of the interfacial thickness, as determined by either the Raman method or small-angle X-ray scattering. Studies of n-alkanes and polyethylenes in the melt and in the crystalline state indicate that the 1060 cm-1 band measures both the long trans sequences in the crystalline state as well as short sequences in the interphase and liquid-like regions. The persistence of this band in the melt precludes its use in quantifying the level of crystallinity. For a high molecular weight linear polyethylene it has been found that alpha a determined from the band around 860 cm-1 was less than that determined from the 1303 em-1 band. It was postulated that a fourth element of phase structure was present. The experimental findings for a large range of molecular weight polyethylenes have been confirmed, but an alternate explanation of these results can be given that is consistent with the three basic elements of phase structure. 16 refs. USA

Accession no.803015

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References and Abstracts

Item 11 Antec 2000.Conference proceedings. Orlando, Fl., 7th-11th May, 2000, paper 499 CHARACTERIZATION OF POLYETHYLENE BLENDS BY USING NOVEL TECHNIQUES SUCH AS THE SUCCESSIVE SELFNUCLEATION AND ANNEALING (SSA) AND THE FOURIER SELF-DECONVOLUTION IR SPECTROSCOPY (FSD-IR) Sierra J D; Ospina S; Montoya N; del Pilar Noriega M; Osswald T A Instituto de Capacitacion e.Investigacion del Plastico y del Caucho; Wisconsin-Madison,University (SPE) The characterisation of binary and ternary blends of polyethylenes by successive self-nucleation and annealing (SSA), and by Fourier self deconvolution infrared spectroscopy was investigated. The SSA investigation, which is capable of determining lamellar thickness distributions, short chain branching, and characterising grafted polymers, was done using a conventional heat flow calorimeter. Self deconvolution is a Fourier transform mathematics technique to enhance the resolution between adjacent bands, to quantify linear low density polyethylene. It was concluded that SSA was a low-cost alternative for the characterisation of novel metallocene polymers. 7 refs. COLOMBIA; USA

Accession no.802029 Item 12 Colloid & Polymer Science 278, No.10. Oct.2000, p.946-53 TIME-RESOLVED NEAR-INFRARED AND TWODIMENSIONAL NEAR-INFRARED CORRELATION SPECTROSCOPIC STUDIES ON POLYMERIZATION OF THE SILANE COUPLING AGENT PERFLUOROOCTYLTRIMETHOXYSILANE Ogasawara T; Nara A; Okabayashi H; Nishio E; O’Connor C J Nagoya,Institute of Technology; Nicolet Japan Corp.; Auckland,University Both two-dimensional near infrared (2D NIR) and time resolved near infrared (TR NIR) indicate the progress of the polymerisation process of perfluorooctyltrimethoxysilane catalysed by hydrogen chloride in ethanol. TR NIR was used to monitor the bands associated with water and ethanolic hydroxyl groups during the reaction. Consumption and release of water molecules was observed strongly in the initial reduction, followed by rapid increase of the band at 5164 reciprocal centimetres. The band at 4825 reciprocal centimetres (associated with OH groups) increased throughout the reaction as a result of the hydrolysis of methoxy groups and formation of silanols. 2D NIR allowed the observance, from calculated asynchronous spectral maps, of two

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species of silanol groups whose behaviour during the reaction is considered. 33 refs JAPAN; NEW ZEALAND

Accession no.796713 Item 13 Applied Spectroscopy 54, No.9, Sept.2000, p.1384-90 FT-RAMAN SPECTROSCOPIC INVESTIGATIONS ON THE ORGANIC CROSSLINKING IN HYBRID POLYMERS. I. MODEL REACTIONS OF SIMPLE EPOXIDES Riegel B; Kiefer W; Hofacher S; Schottner G Wuerzburg,University; Fraunhofer-Institut fuer Silicatforschung Model reactions of epoxypropane and epoxyhexane were analysed using Fourier Transform-Raman spectroscopy and Carbon-13 NMR spectroscopy to obtain information on the possible products of ring opening in epoxy silane-based solgel derived hybrid polymers. A mixture of epoxyalkane, tetramethoxysilane and aluminium sec-butylate was employed to investigate behaviour during the sol-gel process. Raman band and NMR peak assignments for various reaction products are presented and discussed. 24 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.794693 Item 14 Applied Spectroscopy 54, No.8, Aug.2000, p.1192-202 MEASUREMENT OF THE SENSITIVITY AND PHOTOMETRIC ACCURACY OF FT-IR SPECTROMETERS Bowie B T; Griffiths P R Idaho,University A method is developed to investigate the sensitivity and photometric accuracy of a Fourier transform infrared (FTIR) spectrometer by statistically analysing a set of spectra of a 75 mu m thick film of PETP. These tests are applied to three commercial FT-IR spectrometers. Although the photometric accuracy of all three instruments is generally better than 0.1%, small artifacts that cannot be removed by signal averaging are often observed where strong bands should have a transmittance of less than 0.01%. Binding of the moving mirror of one of the spectrometers appears to degrade its performance. When the standard deviation of the noise on 100% lines is calculated conventionally, none of the instruments give efficient signal averaging after 25 scans have been co-added, because of small slopes in the baseline. By calculation of the noise level by successive difference, signal averaging is improved, but even with this approach the noise level on one of the instruments does not decrease after 100 scans are averaged. 8 refs. USA

Accession no.789824

© Copyright 2001 Rapra Technology Limited

References and Abstracts

Item 15 Polymer Science Series B 42, Nos.5-6, May-June 2000, p.169-74 IR SPECTROSCOPY STUDY OF POLYMER POROSITY Pakhomov P M; Kruglova E V; Khizhnyak S D Tver,State University IR spectroscopic method is developed for evaluating the porosity (concentration and size of pores) in polymers. PE and PAN films of various porosity are prepared from the solutions in liquid and solid paraffins. The concentration and maximum pore size in the bulk and in a surface layer of the samples are determined by IR spectroscopy in the transmission and reflection modes, respectively. The results obtained are in agreement with the data of optical and atomic force microscopy. 12 refs. RUSSIA

Accession no.786845 Item 16 Applied Spectroscopy 54, No.7, July 2000, p.968-73 INFRARED RHEO-OPTICS OF BOMBYX MORI FIBROIN FILM BY DYNAMIC STEP-SCAN FTIR SPECTROSCOPY COMBINED WITH DIGITAL SIGNAL PROCESSING Sonoyama M; Nakano T Tokyo,University of Agriculture & Technology; Nippon Bio-Rad Laboratories Dynamic step-scan FTIR spectroscopy combined with software-based digital signal processing(DSP) was applied for IR rheo-optical measurements of isotactic PP and regenerated Bombyx mori silk fibroin film undergoing sinusoidal mechanical strain. Comparative measurements of dynamic IR spectra of PP film using the DSP-based method and two lock-in amplifiers(LIAs) indicated that a high signal-to-noise ratio(SNR) advantage was attained by the DSP method combined with the LIA method. With the DSP technique, dynamic spectra of Bombyx mori silk fibroin film with high SNR were successfully recorded in the whole mid-IR region in only 30 min. The dynamic spectra revealed that stress-induced dynamic reorientation in fibroin film was mainly localised in the segment with beta-sheet conformation and was almost synchronous with the applied mechanical strain. Two-dimensional correlation analyses of the dynamic spectra showed that the broad amide I band was resolved into three components whose positions were dependent on secondary structures, that the dynamic behaviour of tyrosine residues was extracted by separation of the feature due to its aromatic side chains from the broad envelope of the amide I band in the 2D asynchronous map and that the dynamic behaviour of the amide A and B modes was the same as that of the amide II mode, when the mechanical strain was applied to fibroin film. 36 refs.

Item 17 Polymer 41, No.24, 2000, p.8659-71 RAMAN MICROSCOPIC STUDIES OF THE DISTRIBUTION OF THE FUNGICIDE FLUORFOLPET IN PLASTICISED PVC FILMS Mura C; Yarwood J; Swart R; Hodge D Sheffield,Hallam University; Avecia Ltd. Confocal Raman microscopy was used to study the distribution and redistribution (by leaching) of the fungicide Fluorfolpet (N-dichlorofluoromethylthiophthalimide, 5%) in PVC films containing various levels of DOP plasticiser. The distribution of both DOP and Fluorfolpet was found to be uneven on a micron scale, but there was no evidence of inhomogeneity of distribution of either of these on a macroscopic scale. There was little or no leaching of DOP into water. Leaching of Fluorfolpet from the films was observed and the redistribution of Fluorfolpet molecules (measured by mapping and depth profiling) showed that this leaching depended strongly on the DOP concentration or the amount of water penetrating the film. The results were discussed. 51 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.784928 Item 18 ACS Polymeric Materials: Science & Engineering.Spring Meeting 2000.Volume 82.Conference proceedings. San Francisco, Ca., 26th-30th March 2000, p.404-5 DEGRADATION OF POLYURETHANES AND EPOXIES; STEP-SCAN PHOTOACOUSTIC FTIR AND IR/RAMAN IMAGING Kim H; Urban M W Cessna Aircraft Co.; Southern Mississippi,University (ACS,Div.of Polymeric Materials Science & Engng.) Epoxy and polyurethane films were applied by spraying to aluminium alloy substrates and exposed to UV light at 60 C to accelerate the effect of UV exposure. The resulting degradation was studied using step-scan Fourier transform infrared (FTIR) spectroscopy, FTIR microscopy and Raman chemical imaging. The epoxy films formed cracks following 5 weeks exposure, associated with a higher concentration of primary amine groups, indicating higher degradation, whilst in the non-cracked areas the intensity of the N-H deformation band at 1509 /cm increased, indicating diminished crosslinking reactions. In addition the C-N bond stretching band at 1296 /cm decreased due to C-N bond cleavage of tertiary amine groups. The formation of polyurea was observed in the polyurethane coating, attributed to crosslinking reactions of urethane NH groups and NCO from the hexamethylene diisocyanate used for its synthesis. 10 refs.

JAPAN

USA

Accession no.785947

Accession no.784762

© Copyright 2001Rapra Technology Limited

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References and Abstracts

Item 19 ACS Polymeric Materials: Science & Engineering.Spring Meeting 2000.Volume 82.Conference proceedings. San Francisco, Ca., 26th-30th March 2000, p.398-9 MAPPING AND IMAGING ORIENTATION, CRYSTALLINITY AND CHEMICAL COMPOSITION IN POLYMER ARTICLES USING INFRARED AND RAMAN MICROSCOPIES Everall N J; Chalmers J M; Kidder L H; Lewis E N; Schaeberle M; Levin I ICI plc; Spectral Dimensions Inc.; US,National Institutes of Health (ACS,Div.of Polymeric Materials Science & Engng.)

San Francisco, Ca., 26th-30th March 2000, p.378-9 STRATIFICATION PROCESSES IN LATEXES; ATR, PHOTOACOUSTIC, AND IR/RAMAN IMAGING STUDIES Zhao Y; Urban M W Southern Mississippi,University (ACS,Div.of Polymeric Materials Science & Engng.) The surface distribution of sodium dioctyl sulphosuccinate and sodium dodecylsulphate surfactant molecules in films formed from poly(styrene-co-n-butyl acrylate-comethacrylic acid) latex was investigated using Fourier transform infrared (FTIR) and Fourier transform Raman spectroscopies, and surface morphology and depth profiling were investigated using attenuated total reflectance FTIR. It was concluded that these techniques were effective for the study of surfactant stratification during the latex film formation. The concentration of surfactant aggregates was significantly higher at the film/air interface than at the film/ substrate interface, with surfactant hydrophilic groups exhibiting preferential parallel orientation, and hydrophobic groups preferential perpendicular orientation to the latex film surface, the degree of orientation being surfactant structure related. 21 refs.

The use of a fibre-coupled confocal Raman microscope and an infrared microscope for both point mapping and global imaging in the study of spatial variations in polymer chemistry and morphology is illustrated by studies of the curing of the UV-cured acrylate coatings, crystallinity in drawn polyethylene terephthalate (PET) film, molecular orientation in PET bottles, and the analysis of a PES/PEES copolymer blended with epoxy resin and cured at elevated temperature. 8 refs.

USA

USA

Accession no.784750

Accession no.784759 Item 20 ACS Polymeric Materials: Science & Engineering.Spring Meeting 2000.Volume 82.Conference proceedings. San Francisco, Ca., 26th-30th March 2000, p.396-7 INFRARED, RAMAN AND NEAR-INFRARED STUDIES ON STRUCTURE-PROPERTIES RELATIONSHIP IN HIGH DENSITY AND LOW DENSITY POLYETHYLENE Ozaki Y; Amari T; Sasic S; Sato H; Shimoyama M; Kamiya T; Ninomiya T Kwansei-Gakuin,University; Mitsubishi Chemical Corp.; Hyogo,Prefectural Police Headquarters (ACS,Div.of Polymeric Materials Science & Engng.) Infrared, near-infrared, and Raman spectroscopy were used to study high density, linear low density (LLDPE), and low density polyethylene. Overlapping spectral bands were separated using the second derivative, principal component analysis, and two-dimensional correlation analysis. A model was developed, using partial least squares regression, to calculate the density of LLDPE. 1 ref. JAPAN

Accession no.784758 Item 21 ACS Polymeric Materials: Science & Engineering.Spring Meeting 2000.Volume 82.Conference proceedings.

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Item 22 Journal of Polymer Science: Polymer Physics Edition 38, No.13, 1st July 2000, p.1773-87 DIFFUSION MEASUREMENTS USING ATRFTIR SPECTROSCOPY: ACETONE DIFFUSION IN POLYPROPYLENE - USE OF PENETRANT FLUID PRESSURE TO IMPROVE SAMPLE-IRE CONTACT Yi X; Portnoy J; Pellegrino J US,National Inst.of Standards & Technology A simple method for improving the sample film to crystal contact during measurement of the diffusion of liquids into polymer thin films is described using attenuated total reflectance (ATR)-FTIR. The method is based on controlling the penetrant fluid pressure above a threshold value (greater than 230 kilo Pascal) in the ATR flow cell. Using acetone in a commercial polypropylene film, the calculated diffusion time constant was found to be constant at pressures above this threshold value. It was concluded that the apparent good fit between experimental data and a model does not justify complete confidence in the accuracy of the calculated diffusion time constant. A reasonable measure of consistency between experimental conditions and the mass transfer and optical absorbance model assumptions was obtained by monitoring the absorbance of the non-overlap polymer absorbance bands. This indicated whether the required intimate contact between the sample film and crystal was reached and maintained. 16 refs. USA

Accession no.784616

© Copyright 2001 Rapra Technology Limited

References and Abstracts

Item 23 Journal of Macromolecular Science B B39, No.3, 2000, p.387-95 FTIR ANALYSIS OF NANOPARTICLES OF SYNDIOTACTIC POLYSTYRENE CONTAINING SINGLE AND/OR MULTIPLE CHAINS Chen M; Fan Z; Bu H Fudan,University Samples of nanoparticles containing single and/or multiple chains are prepared by precipitation from dilute solutions of syndiotactic PS (s-PS). Vibrational spectra of the nanoparticles are determined at room temperature and are compared with bulk s-PS. Significant changes in line shape and line width are observed in the spectra of the nanoparticles. Infrared analysis of the nanoparticles also indicates a faster crystallisation rate and higher crystallinity than for the bulk sample. 12 refs. CHINA

Accession no.784110 Item 24 China Synthetic Rubber Industry 23, No.4, July 2000, p.219-21 Chinese CURING KINETICS OF PU ELASTOMERS BY FTIR Zaifeng L; Zhenqin X; Caifeng D; Zhaolian G; Dehe L; Guanghua Y Qingdao,Institute of Chemical Technology; Beijing,University of Petroleum The kinetics of curing reaction of PU elastomers is analysed by in situ quantitative FTIR. The reactions, uncatalysed and catalysed by dibutyltin dilaurate (DBTDL), follow second-order kinetics at low conversion. At high conversion, however, the secondorder rate constants decrease with the increase of reaction extent, due to the influence of diffusion control. The reaction kinetics parameters are given and the possible reaction mechanism is further offered. DBTDL is an effective positive catalyst for the reaction of -NCO with OH. 8 refs. CHINA

Accession no.783773 Item 25 Analytical Chemistry 72, No.12, 15th June 2000, p.71R-9R INFRARED SPECTROSCOPY Gillie J K; Hochlowski J; Arbuckle-Keil G A Applied Extrusion Technologies Inc.; Abbott Laboratories; Rutgers,University This review on IR spectroscopy highlights three areas in which it has become increasingly important during the last two years. These areas are two-dimensional infrared (2D IR) spectroscopy, combinatorial chemistry and human health. This trend is quite evident in the abstracts

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examined. The review is focused on articles published during 1998 and 1999, but occasionally includes articles from earlier work if they provide additional information. 148 refs. USA

Accession no.783746 Item 26 Journal of Applied Polymer Science 77, No.4, 25th July 2000, p.764-75. IN SITU FTIR MEASUREMENT OF CARBON DIOXIDE SORPTION INTO POLY(ETHYLENE TEREPHTHALATE) AT ELEVATED PRESSURES Brantley N H; Kazarian S G; Eckert C A Georgia,Institute of Technology Using poly(ethylene terephthalate) near-IR spectroscopy was used to investigate the sorption rate and solubility of carbon dioxide in the polymer at elevated pressures. The effects of carbon dioxide processing on the crystallinity of the poly(ethylene terephthalate) was also studied. 40 refs. USA

Accession no.782739 Item 27 Polymer 41, No.18, 2000, p.6965-8 INVESTIGATION OF GLASS FORMATION AND PHYSICAL AGEING IN POLY(ETHYLENE TEREPHTHALATE) BY FT-IR SPECTROSCOPY Atkinson J R; Biddlestone F; Hay J N Birmingham,University The changes in chain conformation of PETP which occur during glass formation and physical ageing were studied using FTIR spectroscopy. On cooling and on physical ageing, a change from the trans to the gauche conformations of the ethylene units in PETP was found to occur. This was at variance with the results of a previously reported investigation. 12 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.782252 Item 28 Polymer Testing 19, No.4, 2000, p.415-7 CHARACTERIZATION OF POLYEPICHLOROHYDRIN AND COPOLYMERS OF EPICHLOROHYDRINGYLICIDYL ETHERS BY IR SPECTROSCOPY Glavcheev I; Sirashki G; Mateva R Sofia,University of Chemical Technology & Metallurgy; Svistov,D.Tsenov Economic University A study of the possibilities of using infra red spectra for the characterisation of H-bonds formed as the result of macromolecular interactions and the most suitable

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References and Abstracts

absorbencies to be used for qualitative and quantitative calculation used epichlorohydrin, phenylglycidyl ether and butylglycidyl ether as its basis. A good agreement between chemical structure, oxygen atom content and calculated H-bonds was found using IR spectra. 7 refs. BULGARIA; EASTERN EUROPE

Accession no.779577 Item 29 Polymer Bulletin 44, No.3, April 2000, p.293-300 DETERMINATION OF SMALL INTERACTIONS IN POLYMER COMPOSITES BY MEANS OF FTIR AND DSC Canavate J; Pages P; Saurina J; Colom X; Carrasco F Catalunya,Universitat Politecnica; Girona,Universidad A series of composites of polystyrene (PS) and block poly(styrene-butadiene) (SBS) prepared by extrusion blending in the injection screw and injection moulding were studied by Fourier transform infrared (FTIR) analysis. Moulded samples were then dissolved and cast as a film and again studied using FTIR, with higher levels of miscibility noted than on the original moulding. SBS content of the samples was between 20 and 80 percent, with studies also completed on the pure polymers. Differences observed from simulated spectra of the polymer composites were explained by interactions between the two polymers due to partial miscibility. Corroboration of results was provided by calorimetry studies. 16 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; SPAIN; WESTERN EUROPE

Accession no.779461 Item 30 Macromolecules 33, No.9, 2nd May 2000, p.3431-40 FOURIER TRANSFORM INFRARED SPECTROSCOPY OF PERFLUOROCARBOXYLATE POLYMERS Perusich S A Auburn,University Perfluorocarboxylate polymers in the carboxylic methyl ester, potassium salt and carboxylic acid forms were analysed by FTIR transmission and ATR spectroscopies. Band assignments were made for most of the dominant peaks. An absorbance band ratio, comparing the 555/cm C-F band to the 982/cm C-O-C ether band, was found to be a direct measure of the equivalent weight of the polymers. In addition, the transition from the methyl ester form to the acid form was determined by examining the 2969/cm methyl ester band versus the broad 3200/cm band. Quantitative expressions were presented for use in the computation of equivalent weight and acid content based on the FTIR thin film absorbance measurements. The technique used provided a direct measure of the trade-off

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between high anionic selectivity (high equivalent weight) and good conductivity (low equivalent weight). 7 refs. USA

Accession no.778456 Item 31 Macromolecular Rapid Communications 21, No.7, 12th May 2000, p.354-7 IN SITU FTIR SPECTROSCOPIC STUDY OF THE REGULARITY BANDS AND PARTIALORDER MELTS OF ISOTACTIC POLY(PROPYLENE) Xinyuan Zhu; Deyue Yan; Hongxi Yao; Pingfang Zhu Shanghai,Jiao Tong University An experimental method was developed for the determination of the order of the regularity bands of isotactic polypropylene, using fast heating Fourier transform infrared spectroscopy, which resulted in the bands being arranged in terms of the order degree, from high to low: 940, 1220, 1167, 1303, 1350, 841, 998, 900, 808, 1100 and 973 /cm. Partially ordered melt was formed when the crystalline polymer melted, with the crystalline peak shifting to lower temperatures and the exothermic enthalpy increasing, with decreasing degree of order. 23 refs. CHINA

Accession no.778334 Item 32 Macromolecules 33, No.10, 16th May 2000, p.3518-24 REAL-TIME MID-IR MONITORING OF THE INITIATION AND PROPAGATION IN EPOXIINITIATED LIVING ISOBUTYLENE POLYMERIZATIONS Michel A J; Puskas J E; Brister L B Western Ontario,University The initiation and propagation of the polymerisation of isobutylene (IB), initiated by 1,2-epoxy-2,4,4trimethylpentane (TMPO-1)/TiCl4, was monitored in-situ using a fibre optic transmission mid-infrared probe. Polyether formation, the isomerisation of TMPO-1 into 2,4,4-trimethylpentanal, and its complexation by TiCl4 occurred simultaneously with the initiation of the polymerisation. It is proposed that the initiating mechanism involves the formation of tertiary carbocations, by both SN1 and SN2 paths. From the linearity of the first-order plots of monomer consumption, and the near uniformity of the polyisobutylene, it was concluded that living polymerisation conditions prevailed. 16 refs. CANADA

Accession no.778280 Item 33 157th ACS Rubber Division Meeting - Spring 2000. Conference preprints.

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References and Abstracts

Dallas, Tx., 4th-6th April 2000, paper XVIII RAMAN MICRO IMAGING OF POLYMER BLENDS Appel R; Zerda T W; Waddell W H Texas,Christian University; ExxonMobil Chemical Co. (ACS,Rubber Div.) Raman microimaging is used to estimate the effect of the silica filler on phase separation in binary polymer blends composed of BIMS and BR. The domain sizes, relative concentration of polymer components within domains, and distribution of particulate silica filler and zinc stearate curative are characterised for blends of different compositions and history of ageing treatments. The presence of increased concentrations of precipitated silica results in better polymer morphology since domain sizes are reduced. Increased temperature treatment also decreases domain sizes up to about 150 deg.C, but treatment at 200 deg.C appears to induce separation of the elastomer components. Silica is usually found near the centres of the BIMS domains. There is little difference in silica distribution before and after curing. 6 refs. USA

Accession no.778124 Item 34 Polymer News 25, No.5, May 2000, p.172-5 FT-IR DEVICE FOR ON-LINE MONITORING OF CURE REACTIONS UNDER PRESSURE Carotenuto G; Del Nobile A M; Nicolais L Italy,National Research Council; Naples,University A special device is designed to study the effect of pressure on the kinetic behaviour of a commercial phenolic resin by IR spectroscopy (FTIR). Accurate and reproducible spectra are generated, the characteristic IR peaks assigned and the reaction kinetics evaluated by monitoring the rates of peak disappearance. The pressure has the effect to increase both reaction rate and maximum conversion value. 6 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; ITALY; WESTERN EUROPE

Accession no.778119 Item 35 Macromolecular Symposia Vol.150, Feb.2000, p.121-6 EMULSION (CO)POLYMERISATION OF STYRENE AND BUTYL ACRYLATE MONITORED BY ON-LINE RAMAN SPECTROSCOPY van den Brink M; Pepers M; van Herk A M; German A L Eindhoven,University of Technology On-line, in-situ Raman spectroscopy was used to monitor the solution homopolymerisations of styrene and n-butyl acrylate. The results obtained were then applied to the study of the emulsion homopolymerisations of both

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monomers. The data from the emulsions homopolymerisations were then employed to calculate monomer concentrations during the emulsion copolymerisation of styrene and butyl acrylate. 15 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; NETHERLANDS; WESTERN EUROPE

Accession no.777405 Item 36 Macromolecular Symposia Vol.143, Aug.1999, p.323-36 DIFFUSION OF ALCOHOLS AND WATER IN POLYAMIDE 11: A STUDY BY FOURIERTRANSFORM NEAR-INFRARED SPECTROSCOPY Wu P; Siesler H W Essen,University The diffusion of different deuterium-labelled (OD) low molecular weight alcohols and deuterium oxide in polyamide 11 (PA11) was investigated by monitoring the NH/ND exchange in the polymer by Fourier transform near-infrared spectroscopy (FTNIR). The results demonstrate that the diffusion process of the different penetrants is strongly controlled by their molecular structure and geometry. To characterise this phenomenon quantitatively, the diffusion coefficients for the different deuteration agents were determined for PA11. Furthermore, it was shown that with this technique the less ordered regions of the polymer could be separated spectroscopically from the crystalline domains, which are not accessible for the isotopically labelled diffusants. 27 refs. (World Polymer Congress, 37th International Symposium on Macromolecules, Gold Coast, Australia, 12-17 July 1998) EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.770951 Item 37 Macromolecules 32, No.26, 28th Dec.1999, p.8989-95 STUDYING POLY-DISPERSED LIQUIDCRYSTAL FORMATION BY FTIR SPECTROSCOPY. II. PHASE SEPARATION AND ORDERING Bhargava R; Shi-Qing Wang; Koenig J L Case Western Reserve University It is shown that rapid scan FTIR is a powerful tool for monitoring physical changes (phase separation and nematic ordering). Phase separation was observed during the curing process by a scattering-induced change in the absorbance spectrum of the sample. Nematic ordering could be observed and quantified based on a change in a characteristic band of the liquid crystal. Moreover, the phase separation and the onset of nematic ordering were temporarily resolved. The conversion at phase separation decreased strongly with an increase in liquid crystal

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content, while the conversion required for phase separation increased with increasing temperature. The fraction of liquid crystal present as nematic droplets and total fraction of nematic domains in the polymer dispersed liquid crystal were quantified from changes in the vibrational spectrum of the liquid crystal (E7). On the basis of mass balance applied to the closed process, the phase diagram of the system could be determined as a function of curing temperature. Solubility limits obtained by this method agree well with results obtained by other researchers. The concept of a spectroscopic composite plot that completely describes the formation process in a polymer dispersed liquid crystal is proposed. 36 refs. (Part 1, previous paper, this journal, p.8982-8) USA

Accession no.766636 Item 38 Macromolecules 32, No.26, 28th Dec.1999, p.8982-8 STUDYING POLYMER-DISPERSED LIQUIDCRYSTAL FORMATION BY FTIR SPECTROSCOPY. I. MONITORING CURING REACTIONS Bhargava R; Shi-Qing Wang; Koenig J L Case Western Reserve University Real-time FTIR was used to study the curing of a UVcurable prepolymer (NOA65) and its mixtures with liquid crystals. Curing reactions were examined as a function of film thickness, temperature, and liquid crystal content. While there was little dependence of the curing behaviour on the thickness of the film, the effect of temperature was strong. Curing rates exhibited a maximum around 325K, while conversions reached a plateau about 20K higher. Liquid-crystal addition depressed the conversion. However, compared with the neat matrix, the final conversion was significantly lower only for phaseseparating concentrations. The rate of reaction decreased, and the induction period for the onset of polymerising reactions increased, with increasing liquid-crystal concentration. It is concluded that real-time FTIR is a useful tool for monitoring polymer-dispersed liquid crystal formation and optimising curing conditions. NOA65 (from Norland Products Inc.) is a thiolenechemistry curable prepolymer mixture of trimethylolpropane diallyl ether, trimethylolpropane tris(thiol), isophorone diisocyanate ester, and a benzophenone photoinitiator. 34 refs. USA

Accession no.766635 Item 39 Polymer 41, No.8, 2000, p.2961-70 FT-IR STUDIES OF SIDE CHAIN LIQUID CRYSTALLINE THERMOPLASTIC ELASTOMERS

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Nair B R; Gregoriou V G; Hammond P T Massachusetts Institute of Technology The response of a PU with liquid crystals pendant to the soft segments to an applied strain was studied using FTIR linear dichroism. It was found that this complex material followed the trend established in the literature for both side chain liquid crystalline homopolymers and segmented PUs. At low strains, the soft segments aligned with strain, inducing an orientation in ‘lone’ hard segments. Up to strains of 40%, the liquid crystalline mesogens aligned with the strain field and the hard segments in hydrogen bonded domains aligned perpendicular to the field. At strains above 40%, a rearrangement of the ordering was found that resulted in smectic layers and the hard segments aligning parallel to the field. A model was proposed to represent these findings and the cooperative movement of the different macromolecular components of the PU was considered. 37 refs. USA

Accession no.766050 Item 40 Journal of Biomaterials Science: Polymer Edition 10, No.12, 1999, p.1289-302 FTIR SPECTROSCOPIC INVESTIGATION AND MODELLING OF SOLUTE/POLYMER INTERACTIONS IN THE HYDRATED STATE Am Ende M T; Peppas N A Purdue University Attenuated total reflectance infrared spectroscopy is used to investigate possible interactions during transport of oxyprenolol.HCL bovine scrum albumin, alphachymotrypsin and fibrinogen through polyacrylic acid and its random copolymeric gels. Carbonyl and carboxylate ion peak shifts are used to identify drug/gel binding due to electrostatic and hydrogen bond interactions between the polymer carrier and the drugs tested. These findings are used to interpret the decrease in calculated diffusion coefficients of drugs diffusing through these gels and the associated hindering of drug transport. A model is developed to analyse this transport process as a function of the binding heat of the drug with the polymer. 16 refs. USA

Accession no.765134 Item 41 Journal of Polymer Science: Polymer Physics Edition 38, No.2, 15th Jan.2000, p.329-40 EPOXY-AMINE RETICULATES OBSERVED BY INFRARED SPECTROMETRY. II. MODIFICATIONS OF STRUCTURE AND OF HYDRATION ABILITIES AFTER IRRADIATION IN A DRY ATMOSPHERE Ngono Y; Marechal Y CEA/Grenoble

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References and Abstracts

Infrared spectroscopy was used to follow the ageing processes of two epoxy resins. Resin samples were exposed to ionising radiation and the effects at the molecular level, and how the resins modified their hydration mechanisms was discussed. Aromatic amine cured resins are only slightly affected by the radiation, but those cured by alkyl diamines are more sensitive and thus absorb more water.molecules. 14 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; WESTERN EUROPE

Accession no.763885 Item 42 Macromolecular Rapid Communications 20, No.12, Dec.1999, p.607-11 POLYELECTROLYTE COMPLEX LAYERS: A PROMISING CONCEPT FOR ANTI-FOULING COATINGS VERIFIED BY IN-SITU ATR-FTIR SPECTROSCOPY Mueller M; Rieser T; Lunkwitz K; Meier-Haack J Dresden,Institute of Polymer Research In-situ ATR FTIR spectroscopy was used to study the interaction between the differently charged model proteins human serum albumin, lysozyme, immunoglobulin G and multilayer assemblies, which were deposited by alternating adsorption of polyethyleneimine and polyacrylic acid onto silicon crystals. Low adsorbed protein amounts were observed if the top polyelectrolyte layer and the protein were equally charged, whereas enhanced protein adsorption occurred for electrostatic attraction between protein and top polyelectrolyte layer. 18 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.761294

side groups was shown to provide a good fit to the available experimental data. 29 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; UK; WESTERN EUROPE

Accession no.760880 Item 44 Polymer 41, No.4, 2000, p.1597-606 DISTRIBUTION OF INDIVIDUAL COMPONENTS IN THERMOPLASTIC OLEFINS: STEP-SCAN FT-IR PHOTOACOUSTIC PHASE ANALYSIS Kiland B R; Urban M W; Ryntz R A North Dakota State University; Visteon Automotive Systems Fourier transform infrared step-scan photoacoustic spectroscopy was developed to study the composition of thermoplastic olefin films, as a function of depth below the surface. Infrared bands associated with talc, polypropylene (PP), and ethylene-propylene rubber (EPR) were used as depth-profiling probes to identify photoacoustic signals. Experiments were done at various modulation frequencies, enabling a stratification model to be developed. The uppermost layer (0-3 micrometre) showed large changes in talc and PP concentration, whilst the layer below showed a significant decrease in both the phases. In the third layer (6-9 micrometre), all three phases showed the maximum values. In the fourth layer (9-12 micrometre), the talc concentration reduced, whilst concentrations of EPR and PP were observed, decreasing with depth. 32 refs. USA

Accession no.760721

Item 43 Macromolecules 32, No.24, 30th Nov.1999, p.8161-6 VIBRATION MODE INTERACTION IN THE RAMAN SPECTRA OF POLY(1,6-BIS(NCARBAZOLYL)-2,4-HEXADIYNE) Bloor D; Fehn T Durham,University; Bayreuth,University

Item 45 Applied Spectroscopy 53, No.11, Nov.1999, p.1412-8 IN-LINE NEAR-INFRARED MONITORING OF POLYMER PROCESSING. I. PROCESS/ MONITOR INTERFACE DEVELOPMENT Reshadat R; Desa S; Joseph S; Mehra M; Stoev N; Balke S T Toronto,University

The Raman spectrum of the above polydiacetylene was re-examined and analysed in terms of the resonant interaction of backbone and side-group vibration modes. FTIR Raman spectra were recorded for partially and fully polymerised samples. These data complemented earlier studies of the resonance-Raman spectra of partially polymerised crystals conducted at low temps. The multipeaked spectrum, which was observed in the vicinity of the stretching vibration of the backbone carbon double bond, was analysed using these results. A model that incorporated the resonant interaction of the carbon doublebond mode with three vibrational modes of the carbazolyl

Near-infrared inline monitoring of polymer processing means using an optical fibre-assisted spectrometer to obtain spectra of the polymer melt flowing through commonly used processing equipment (an extruder). Conditions in the extruder are typically 200 deg.C and 20 MPa. The design of interfaces between the spectrometer and the molten polymer is shown. Three designs are shown, each permitting monitoring at a different location in the process: a melt-at-die interface, a melt-in-barrel interface and a strand interface. These designs are for monitoring just before the extruder exit, in the main barrel of the extruder and after the product exits from the extruder as a strand,

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References and Abstracts

respectively. All these interfaces protect the inserted optical fibre probe from the harsh environment within the extruder while permitting easy replacement or a probe without interrupting the process. This latter characteristic is very important because it permits easy probe repair as well as the use of other types of probes (for monitoring colour or particles, for example) to be used during a run. Examples of near-infrared spectra obtained with each of the interfaces used with an immiscible blend of PE and PP are shown. Large differences in the spectra demonstrate that the design of the interface will affect multivariate analysis directed at composition prediction. Subsequent papers are directed at using the melt-at-die interface for composition prediction and accounting for nonlinear relationships between absorbance and concentration. 6 refs. CANADA

Accession no.760231 Item 46 Applied Spectroscopy 53, No.11, Nov.1999, p.1398-402 PLASTIC DEFORMATION OF POLYETHYLENE STUDIED BY INFRARED DICHROISM Elkoun S; Seguela R; Depecker C Lille,Universite des Sciences et Technologies; URA CNRS IR dichroism measurements are carried out to investigate the plastic deformation mechanisms of homogeneous and heterogeneous ethylene copolymers issued from the metallocene and the Ziegler-Natta catalyses, respectively. The two copolymers having the same density display significantly different plastic behaviour that should result from different mechanisms of crystal slip. Such mechanisms are analysed on the basis of the main crystal slip systems (100)(001) and (010)(001) having the higher shear compliances. Attention is focused on the Schmid factor, S, of the slip planes, which is the ratio of the shear stress acting on each slip plane to the applied tensile stress. From the orientation functions of the three crystallographic axes of the orthorhombic unit cell, the Schmid factor of the two slip systems is determined as a function of plastic strain. The heterogeneous copolymer exhibits somewhat higher data for the (010)(001) slip, which suggests a preferred activation of this system during the yielding stage. In contrast, the homogeneous copolymer displays close values for the two slip systems, indicating that plastic flow is more likely governed by a combined activation of the two slip systems and with eventual cross slip owing to the common (001) slip direction. 17 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; WESTERN EUROPE

Accession no.760229 Item 47 Applied Spectroscopy 53, No.11, Nov.1999, p.1313-22

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TOWARDS FASTER FT-IR IMAGING BY REDUCING NOISE Bhargava R; Ribar T; Koenig J L Case Western Reserve University Fourier transform infrared (FT-IR) imaging is a powerful technique that can be used to obtain spatially resolved chemical information from a large sample area in a relatively short time. However, temporal resolution of fast FT-IR imaging is limited by rapid of data quality due to increased noise) with faster image acquisition. Various coaddition schemes to reduce noise and improve the quality of images acquired from such systems are presented. The application of the proposed schemes allows for improved signal-to-noise ratio (SNR) characteristics in the resulting data. These schemes are tested by monitoring the dissolution of a polymer film (poly alpha-methyl styrene) by a lowmolecular-weight solvent (methyl isobutyl ketone (MIBK)). Pseudo coaddition improves the SNR by approximately 45%, while the SNR for sampling coaddition is found to scale as aproximately N0.5, where N is the number of coadded pixels. A total acquisition time of about 100 s is achieved, allowing the dissolution process to be monitored by using image acquisitions separated by 3 min. Low noise concentration profiles, linear solvent penetration rate and polymer dissolution rate are measured. Detection limits of approximately 5% and quantification limits of ~20% are achieved using optimal coaddition strategies. This result represents an order of magnitude improvement over untreated data. 25 refs. USA

Accession no.760228 Item 48 156th ACS Rubber Division Meeting - Fall 1999. Conference preprints. Orlando, Fl., 21st-23rd Sept.1999, paper 122 RAMAN STUDY OF KINETICS OF GRAPHITISATION OF CARBON BLACKS Zerda T W; Gruber T Texas,Christian University (ACS,Rubber Div.) Raman spectra of laser heated carbon blacks provide information on the dynamics of graphitisation process. Continuous wave and pulsed-laser heating is used. It is shown that two ordering mechanisms of distinctly different reaction rates are present during the heat treatment. The mechanism dominating during the initial stages of graphitisation is characterised by a very fast rate. The rate during the later stages of the process, after the initial first couple of seconds is orders of magnitude slower. 8 refs. USA

Accession no.759712

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References and Abstracts

Item 49 156th ACS Rubber Division Meeting - Fall 1999. Conference preprints. Orlando, Fl., 21st-23rd Sept.1999, paper 160 REAL-TIME MONITORING OF POLYMERISATION PROCESSES USING A MIDIR FIBREOPTIC PROBE Puskas J E; Michel A J; Brister L B Western Ontario,University (ACS,Rubber Div.) A novel fibreoptic mid-IR probe is developed for the realtime monitoring of polymerisation processes. The probe is equipped with two interchangeable heads: one is an attenuated total reflectance (ATR) head and the other one is a transmission (TR) head. The TR head can monitor very low concentrations (0.1 mmol/L). The ATR probe is used to monitor both homogeneous and heterogeneous isobutylene (IB) polymerisations by the disappearance of the C=C double bond stretch at 1655 cm -1 and of the C-H stretch in the CH3- group at 1375 cm -1. Polymer formation is monitored by the appearance of the following signals characteristic of polyisobutylene (PIB): the 1230 cm -1 band identified as the vibrations of the distorted carbon tetrahedrons (-C(CH3)2- groups); the 1364/1391 cm -1 asymmetrical doublet representing the C-H bending of the t-butyl groups; and the 1470 cm-1 methylene ‘scissoring’ vibration. The TR probe is used to monitor the initiation step in a living IB polymerisation initiated by 2-(2,2-dimethyl-propyl)-2-methyl-oxirane (TMPO-1)/ TiCl4. The appearance of bands characteristic of aldehyde/ ketone isomerisation products and polyethers at 1635, 1665 and 1100 cm-1, respectively, is observed in realtime. The disappearance of the C-O-C stretching at 1260 cm-1 can only be monitored in the absence of IB because of overlapping with the 1230 cm-1 band. Due to the sensitivity of the TR probe the 1655 cm-1 band is saturated at the beginning of the polymerisation, so IB consumption is followed by monitoring the 2nd overtone of the =CH2 bending at 1780 cm-1. The results demonstrate the versatility and powerfulness of this new method. 8 refs. CANADA

Accession no.759419 Item 50 Polymer Degradation and Stability 67, No.1, 2000, p.149-58 FTIR STUDY OF THE EFFECT OF HYDROLYTIC DEGRADATION ON THE STRUCTURE OF THIN PETP FILMS Sammon C; Yarwood J; Everall N Sheffield,Hallam University; ICI Research & Technology Centre Thin films (about 100 nanometres) were prepared by spin casting. They were treated with pure water or 1% potassium hydroxide at 90C for up to 8 days. Changes in chemistry and morphology were followed using FTIR and Reflection Absorption Infrared Spectroscopy. Dramatic

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changes in the intensity of the characteristic carbonhydrogen band were noted as a function of degradation of the samples degraded by both the water and the alkali. This was interpreted as resulting from a change in the environment of the aliphatic methyl groups and subsequent extensive hydrogen bonding, due to an increase in the numbers of hydrophilic end groups. Differences in bands assigned to carbonyl groups and hydroxyl groups suggested formation of different hydrogen bonded species in the two systems. The autocatalytic nature of the hydrolysis in pure water was confirmed and evidence for the so-called ‘chemicrystallisation effect’, with crystallinity increasing with degradation, was observed. The thin nature of the films allowed a spectroscopic insight into the morphology of the degrading films as a function of treatment time. 26 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.758436 Item 51 Polymer International 48, No.11, Nov.1999, p.1108-12 IRREVERSIBILITY OF STRETCHINGINDUCED LOCAL CONFORMATIONAL CHANGES AS VERIFIED THROUGH AN FTIR DICHROISM STUDY FOR PVC Guarrotxena N; Millan J-L Madrid,Instituto de Ciencia y Tec.de Polim. Polyvinyl chloride (PVC) films were stretched to various elongation ratios and the dichroic behaviour of 615 and 637 /cm bands of the infrared spectrum was investigated. The evolution of the dichroic ratios and of the relative absorbance of the bands in the direction perpendicular to that of stretching were compared so that the occurrence of local chain orientation related to the conformational change GTTG-TT to GTGTTT at mmr isotactic tetrads could be differentiating from the normal orientation of syndiotactic sequences, to confirm that this conformational change occurs when stretching PVC. 19 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; SPAIN; WESTERN EUROPE

Accession no.757990 Item 52 Journal of Polymer Science: Polymer Physics Edition 37, No.17, 1st Sept.1999, p.2353-9 FAST FTIR IMAGING: A NEW TOOL FOR THE STUDY OF SEMICRYSTALLINE POLYMER MORPHOLOGY Snively C M; Koenig J L Case Western Reserve University Fast FTIR imaging was used to study the distribution of chemical species and the degree of orientation in semi-crystalline systems. The systems investigated were pure poly(ethylene glycol) (PEG) and blends of

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PEG with PEO, PMMA or PVAC. The technique was shown to be useful for determining the distribution of species with different molecular weights and for determining the degree of segregation of the different blend components. Using an IR polariser, the degree of orientation was determined in the systems by generating spatially-resolved dichroic ratio images. 20 refs. USA

Accession no.757179 Item 53 Journal of Polymer Science: Polymer Physics Edition 37, No.16, 15th Aug.1999, p.2261-8 STUDYING ANOMALOUS DIFFUSION IN A LIQUID CRYSTAL/POLYMER SYSTEM USING FAST FTIR IMAGING Snively C M; Koenig J L Case Western Reserve University Fast FTIR imaging showed that the diffusion of liquid crystal 4-n-pentyl-4'-cyanobiphenyl into a poly(butyl methacrylate) matrix exhibited anomalous diffusion behaviour. A fit to several models was attempted, but no single model described the observed diffusion behaviour adequately. A simple mass uptake analysis would have indicated that diffusion occurred according to Fick’s second law, whereas fast FTIR correctly identified the process as anomalous. 20 refs. USA

Accession no.757170

Item 55 Macromolecules 32, No.21, 19th Oct.1999, p.7147-55 STATIC AND DYNAMIC FT-IR LINEAR DICHROISM STUDIES OF PLASTICIZATION EFFECTS IN A POLYURETHANE ELASTOMER Graff D K; Haochuan Wang; Palmer R A; Schoonover J R Los Alamos National Laboratory; Duke,University The physical role of plasticisation was assessed by combining FTIR data for plasticised Estane 5703 (a polyester-urethane from B.F.Goodrich) subjected to mechanical deformation with spectral differences as a function of added plasticiser. The orientation functions and dichroic difference data for Estane showed that, in static stretching, the soft domains reached orientation saturation before the hard domains. With added plasticiser, hydrogen bonding to the hard segments was disrupted and the Tg of the soft domain decreased, indicating that plasticiser remained solubilised in the soft domain. On the time scale of the static experiment, plasticisation diminished the ability of both domains to reorient, while the plasticiser itself did not orient. With added plasticiser, neither domain reached orientation saturation during the pre-stretching process and dynamic distortion resulted in a similar response from both domains. Bimodal bands in the dynamic data indicated that the strain applied on a rapid time scale (20 Hz) allowed resolution of the components of differently oriented bands. 34 refs. GOODRICH B.F. USA

Accession no.756264 Item 54 Macromolecules 32, No.20, 5th Oct.1999, p.6807-12 IN SITU SPECTROELECTROCHEMICAL RAMAN STUDIES OF POLY(3,4ETHYLENEDIOXYTHIOPHENE) (PEDT) Garreau S; Louarn G; Buisson J P; Froyer G; Lefrant S Nantes,Institut des Materiaux The results are reported of a spectroelectrochemical study of the oxidative doping of PEDT carried out using UV-vis-NIR optical absorption spectroscopy and resonance Raman scattering spectroscopy with two excitation lines, namely green (514 nm) and infrared (1064 nm). Changes in the Raman spectra during doping are interpreted in terms of modification of electronic distribution along the chain. Results of vibrational calculations, determined using a symmetrised dynamical matrix model, are compared with experimental data and a coherent set of force constants related to the assignment of the Raman bands and estimation of the polymer chain modification during doping is proposed. 17 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; WESTERN EUROPE

Accession no.756395

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Item 56 Macromolecules 32, No.19, 21st Sept.1999, p.6319-25 STRUCTURAL AND CONFORMATIONAL CHARACTERIZATION OF POLY(ETHYLENE 2,6-NAPHTHALATE) BY INFRARED SPECTROSCOPY Vasanthan N; Salem D R TRI/Princeton X-ray diffraction analysis showed that poly(ethylene 2,6naphthalate) (PEN) film, annealed from 160 to 260 C crystallised in the alpha-crystal form, whilst crystallisation directly from the melt yielded the beta-crystal form when the crystallisation temperature (Tc) was greater than 200 C, and in the alpha form at lower Tc. Infrared spectra from PEN samples containing alpha, beta, and amorphous phases were determined, and the amorphous contribution digitally subtracted to yield characteristic spectra of the amorphous, alpha, and beta phases. It is proposed that the alpha crystal form adopts an all-trans conformation, whilst the beta crystal form adopts a conformation with appreciable gauche character. Conformational changes in PEN occurred due to the rotation of the naphthalene ring as well as rotation of the ethylene glycol units. The

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References and Abstracts

normalised absorbances of the bands at 824 and 814 /cm were correlated to polymer density, and could be used to represent the amorphous and alpha crystalline phases, respectively. Using drawn PEN film, the assignment of the amorphous 1338 /cm band to the trans conformation was studied. 32 refs. USA

Accession no.756087 Item 57 Macromolecules 32, No.19, 21st Sept.1999, p.6307-18 TWO-DIMENSIONAL FOURIER TRANSFORM RAMAN CORRELATION SPECTROSCOPY STUDIES OF POLYMER BLENDS: CONFORMATIONAL CHANGES AND SPECIFIC INTERACTIONS IN BLENDS OF ATACTIC POLYSTYRENE AND POLY(2,6-DIMETHYL-1,4PHENYLENE ETHER) Ren Y; Murakami T; Nishioka T; Nakashima K; Noda I; Ozaki Y Kwansei-Gakuin,University; Idemitsu Petrochemical Co.Ltd.; Saga,University; Procter & Gamble Co. Fourier transform Raman spectra were determined for atactic polystyrene (PS), poly(2,6-dimethyl-1,4phenylene ether) (PPE) and their blends, compositiondependent spectral variations of the blends being analysed using generalised two-dimensional correlation spectroscopy to study the conformational changes and blend-interactions. The two-dimensional synchronous correlation analysis was able to discriminate between the bands of PS and those of PPE, and was able to detect bands which were not readily identifiable in onedimensional spectra. The main chain conformation of PS underwent a drastic change on blending with PPE. Abnormal behaviour of bands at 1448 and 1329 /cm was attributed to backbone methylene vibrations, and of the band at 1070 /cm to C-C stretching vibration. Numerous out-of-phase band variations were observed. It was concluded that not only the phenyl ring of PS and PPE, but also the CH3 groups of PPE played an important role in the formation of the blends. 41 refs. JAPAN; USA

Accession no.756086 Item 58 Journal of Applied Polymer Science 74, No.11, 9th Dec.1999, p.2703-15 KINETIC STUDY OF PHENOLIC RESIN CURE BY IR SPECTROSCOPY Carotenuto G; Nicolais L Naples,University Fourier transform infra red spectroscopy was used to study the cure reaction and reaction kinetics of a commercial phenolic resin, using IR spectra in the absorbance mode. It was found that below 140 deg. centigrade that the

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kinetics of the reaction followed the Jander kinetic model and that a diffusive mechanism was in control. Above 140 deg.C a homogenous first order reaction model best described the reaction, as indicated by analysis using integral methods on the isothermal data. Other models tested, including diffusion controlled reactions, nucleation and growth kinetics and phase boundary movement did not fit the observed data as well as the first order homogenous model. A proposal for a mechanistic model for the resol cure at temperatures greater than 140 deg.C is made. 34 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; ITALY; WESTERN EUROPE

Accession no.756012 Item 59 Polyurethanes Expo ’99. Conference proceedings. Orlando, Fl., 12th-15th Sept.1999, p.303-11 FIBRE OPTIC FTIR: A NOVEL PUR/PIR CATALYST DEVELOPMENT TOOL McDaniel P L; Johnson G L; Kniss J G; Sabram K A Air Products & Chemicals Inc. (American Plastics Council,Alliance for the Polyurethanes Industry) Development of new catalysts promoting different phases of PU foam formation (blowing, gelling, crosslinking) is typically done using a series of physical and handmix generated reactivity profile properties. The ability to understand the evolution of chemical species associated with rigid PU/polyisocyanurate (PUR/PIR) foam formation has been historically only inferred based on their final distribution in the fully cured foam using FTIR or solid state carbon-13 NMR. Neither technique gives insight into the reactions as they occur. Recently, the use of IR transmitting optical fibres as evanescent wave sensors and a mathematical deconvolution technique (iterative target transformation factor analysis) to extract and follow the isocyanate, urea, urethane and trimer concentrations as they occur in both lab scale and machine scale foam production have been refined. The fibre optic probe used can be placed at specific locations within the growing foam to target the evolution of isocyanate chemistries at the surface or core of the foam. The specificity of the technique, speed of data acquisition and portability of equipment all make this method ideal as a tool to fundamentally probe how catalysts alter the distribution of individual chemical species during the initial moments in foam formation. Its utility in understanding the mechanism whereby a novel new catalyst, Polycat 48, improves dimensional stability in a HCFC-141b blown appliance formulation, is demonstrated. The fibre optic FTIR results for Polycat 48 are contrasted to a control catalyst blend of Polycat 5 and Polycat 41 in the same formulation. 10 refs. USA

Accession no.755697

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References and Abstracts

Item 60 Journal of Polymer Science: Polymer Physics Edition 37, No.19, 15th Sept. 1999, p.2642-50 IR SPECTRA STUDIES OF CORE-SHELL TYPE WATERBOURNE POLYACRYLATEPOLYURETHANE MICROEMULSIONS Dong A; Wan T; Feng S; Sun D Edited by: Tianjin,University FTIR spectroscopy was used to study hydrogen bonding in films of polyurethane and core shell type polyacrylatepolyurethane microemulsions. The effects of hydrogen bonding on composition, core shell ratio and its relationship to crosslinked structures (Type A and B) was revealed. Shifts of the -NH and C=O stretching bands to higher frequencies and the -NH bending bands to lower frequencies, with increase in acetone C=O number in the core reveals that the hydrogen bonds are broken between the soft and hard segments and those in the short range order in the hard segment phase. 24 Refs. CHINA

Accession no.755231 Item 61 Journal of Polymer Science: Polymer Chemistry Edition 37, No.16, 15th Aug.1999, p.3317-27 MICRO-RAMAN INVESTIGATIONS OF PVDFBASED PROTON-CONDUCTING MEMBRANES Mattsson B; Ericson H; Torell L M; Sundholm F Chalmers University of Technology Proton-conducting membranes were prepared by grafting poly(vinylidene fluoride) (PVDF) with styrene followed by sulphonation. The depth and surface distribution of the polystyrene grafts and crosslinker, and the sulphonation efficiency were studied using confocal Raman microspectroscopy. Highly grafted samples had a homogeneous distribution of grafts and homogeneous sulphonation, whereas uneven graft distributions were observed in samples with low and intermediate degrees of grafting. The crosslinker concentration in the interior of the film was approximately 50% of the surface concentration. Sulphonation efficiencies were poor at low graft levels, and were further inhibited by the presence of divinyl benzene crosslinker. At degrees of grafting in excess of 60%, the sulphonation efficiency was not affected by the crosslinker. The matrix polymer structure was largely retained after irradiation, grafting, and sulphonation. 32 refs. SCANDINAVIA; SWEDEN; WESTERN EUROPE

Accession no.753415 Item 62 Progress in Organic Coatings 35, No.1-4, Aug.1999, p.197-204 DEPTH PROFILING OF UV CURED COATINGS CONTAINING PHOTOSTABILIZERS BY

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CONFOCAL RAMAN MICROSCOPY Schrof W; Beck E; Koniger R; Reich W; Schwalm R BASF AG Confocal Raman microscopy combines chemical information from vibrational spectroscopy with the spatial resolution of confocal microscopy. Examples of its use are given, including: the investigation of variation of crosslinking with depth in thicknesses of up to 0.5 mm in UV-cured coatings; variations of curing with depth in pigment formulations, in thicknesses of up to 30 micrometre; and studies of the effect of UV light stabilisers on the UV curing of coating formulations. 11 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.752449 Item 63 Journal of Applied Polymer Science 74,No.3, 17th Oct.1999, p.532-40 TETRAFUNCTIONAL EPOXY RESINS:MODELING THE CURING KINETICS BASED ON FTIR SPECTROSCOPY DATA Musto P; Martuscelli E; Ragosta G; Russo P; Villano P Italy,National Research Council The curing kinetics of two thermosetting systems based on a tetrafunctional epoxy resin are investigated by Fourier transform infrared spectroscopy. Two formulations are studied, in which the hardener is an aromatic diamine and a carboxylic dianhydride, respectively. The quantitative evaluation of the epoxy conversion is based on spectra collected in the nearinfrared range (8000-4000 cm -1) as well as in the medium IR range (4000-400 cm -1). The kinetic parameters evaluated in the above frequency intervals are significantly different. The reasons for such a discrepancy are critically discussed. Several kinetic models, based on the widely employed Kamal approach, are applied to verify their predictive capability. Satisfactory results are obtained for the amine-cured system, particularly with a modified equation taking into account the autocatalytic nature of the process as well as a limiting diffusional effect. Less accurate results are achieved for the anhydride-cured system. 23 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; ITALY; WESTERN EUROPE

Accession no.752308 Item 64 Journal of Applied Polymer Science 74,No.3, 17th Oct.1999, p.516-22 REACTIVITY RATIOS OF NCYCLOHEXYLMALEIMIDE AND METHYLMETHACRYLATE BY INFRARED SPECTROSCOPY Dong S; Wei Y; Zhang Z Harbin,Institute of Technology

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References and Abstracts

The copolymerisation of N-cyclohexylmaleimide (CHMI) and methyl methacrylate (MMA) with azobisisobutyronitrile as the initiator is investigated. IR spectroscopy is applied to determine the copolymer compositions of the copolymers synthesised at 60, 70, 80 and 90 deg.C while the conversions of the copolymerisations are controlled to be below 10%. According to the Mayo-Lewis equation, the reactivity ratios of N-cyclohexylmaleimide and methyl methacrylate are calculated. It is proved that Ncyclohexylmaleimide is less reactive, and the optimum temperature of the copolymerisation is 80 deg C. 8 refs. CHINA

Accession no.752306 Item 65 Macromolecules 32, No.17, 24th Aug.1999, p.5552-60 RAMAN SPECTROSCOPIC CHARACTERISATION OF ASSOCIATION AND THERMOREVERSIBLE GELATION IN AQUEOUS SYSTEMS OF POLY(NACETAMIDOACRYLAMIDE) Ostrovskii D; Jacobsson P; Nystrom B; Marstokk O; Kopperud H B M Chalmers University of Technology; Oslo,University; Jotun AS A study was made of self-association and thermoreversible gelation in aqueous solutions of poly(N-acetamidoacrylamide) using Raman spectroscopy. The presence of polymer-polymer coordination was observed even at low concentrations, indicating polymer cluster formation. The influence of sodium thiocyanate, as denaturant, on intermolecular and intramolecular interactions was also examined and the effects of polymer concentration, level of denaturant addition and type of solvent, on gel formation evaluated. 41 refs. NORWAY; SCANDINAVIA; SWEDEN; WESTERN EUROPE

Accession no.752236 Item 66 Macromolecular Symposia Vol.141, 1999, p.103-16 RAMAN SPECTROSCOPY FOR POLYMER CHARACTERISATION IN AN INDUSTRIAL ENVIRONMENT Everall N; King B ICI Wilton Research Centre The versatility of Raman spectroscopy for the on-line analysis of polymers both in the laboratory and also insitu on the production line is demonstrated and the benefits and disadvantages of the technique as an on-line method are considered. Application of the technique to an analysis of acrylic terpolymers, monitoring of polymerisation and on-line measurement of morphology/composition is

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considered and difficult on-line sampling situations are briefly discussed. 14 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.752092 Item 67 Computational and Theoretical Polymer Science 9, No.3/4, 1999, p.327-33 CONFORMATIONAL DEPENDENCE OF RAMAN FREQUENCIES AND INTENSITIES IN ALKANES AND POLYETHYLENE Koglin E; Meier R J Julich,Institute of Applied Physical Chemistry; DSM Research Raman vibrational frequencies and intensities of octane, dodecane and hexadecane conformers were calculated using quantum mechanical ab initio methods. The results agreed with various trends observed in the experimental spectra of alkanes, as well as several observations from the experimental Raman spectra of PEs. The data obtained indicated that ab initio calculated Raman data on alkanes provided valuable information regarding the interpretation of polymer Raman spectra, in particular information concerning issues where interpretation based on experimental verification was not possible. 23 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; NETHERLANDS; WESTERN EUROPE

Accession no.750357 Item 68 Antec ’99. Volume II. Conference proceedings. New York City, 2nd-6th May 1999, p.2502-6. 012 MEASURING THE DIFFUSIVITY OF ADDITIVES IN POLYMER FILMS USING IN SITU FTIR-ATR SPECTROSCOPY Gaghardi C A.; Muire L B; Hirt D E Clemson,University (SPE) In many polymer-film applications, additives migrate from the bulk of a film to the film surfaces. For these cases, it is more realistic to measure the additive diffusivity in a diffusion-out mode rather than using a mass-sorption (diffusion-in) experiment. This is particularly true for additives that are solids at the testing temperature. This research focuses on the evaluation of additive diffusivity in a diffusion-out mode via in situ FTIR-ATR spectroscopy, which has the advantage of requiring only small samples of thin films. The technique is described, including methods to obtain reproducible contacting pressure between a film sample and an ATR crystal and to perform in situ experiments at elevated temperatures. Diffusivity results are presented for the migration of an erucamide slip agent in LLDPE films. 11 refs. USA

Accession no.749605

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Item 69 Antec ’99. Volume II. Conference proceedings. New York City, 2nd-6th May 1999, p.2429-32. 012 INFRARED CHARACTERISATION OF VINYL CINNAMATE COPOLYMER BLENDS BEFORE AND AFTER UV EXPOSURE Coleman M; Hu Y; Painter P C Pennsylvania,State University (SPE) During the past three years or so, chain connectivity and its effect on the free energy of mixing and phase behaviour of (co)polymer blends has been studied. IR spectroscopy has been the primary tool because in carefully chosen mixtures it is possible to measure the fraction of hydrogen bonded groups present as a function of composition and temperature. Attention is now turned to the effect of crosslinking one or both of the (co)polymers in the blend and the results of recent FTIR spectroscopic studies are presented. USA

Accession no.749591 Item 70 Antec ’99. Volume II. Conference proceedings. New York City, 2nd-6th May 1999, p.2424-8. 012 MOLECULAR ANALYSIS OF POLYMERS BY FTIR PHOTOACOUSTIC SPECTROSCOPY McClelland J F; Jones R; Bajic S MTEC Photoacoustics Inc.; Iowa State University (SPE) FTIR photoacoustic spectroscopy (PAS) has advantages relative to conventional IR techniques (transmission, reflection and emission) because it is non-destructive, does not involve sample preparation and can probe samples with compositional gradients and layers. The theory, instrumentation, methods and applications of FTIR-PAS are discussed and results are presented on several polymer analyses based on FTIR-PAS. 4 refs. USA

Accession no.749590 Item 71 Antec ’99. Volume II. Conference proceedings. New York City, 2nd-6th May 1999, p.1937-41. 012 IN-LINE MONITORING OF MULTIPLE ADDITIVES IN POLYETHYLENE MELT USING FIBRE-OPTIC SPECTROSCOPY Li J; Hansen M G Tennessee,University (SPE) The feasibility of simultaneous in-line monitoring of additives Irganox 1076, Irgafos 168, Tinuvin 622, erucamide and Armostat 310 is studied in molten LDPE. The near IR (NIR) and UV spectroscopic systems used for the determination of additives are described. Based

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on Partial Least Square (PLS) multivariate regression analysis, calibration models are built for predicting the concentrations of additives. It is found that some additives can be predicted reliably. 7 refs. USA

Accession no.748748 Item 72 Polymer Testing 18, No.7, 1999, p.551-7 DIRECT DETERMINATION OF VINYL ACETATE CONTENT OF ETHYLENE-VINYL ACETATE COPOLYMERS IN THICK FILMS BY INFRARED SPECTROSCOPY Meszlenyi G; Kortvelyessy G Szeviki Organic Chemistry Research Institute An IR spectroscopic method was developed for the determination of vinyl acetate content in thick (about 100 micrometres) films of EVAs. The A3460/A3610 ratio was used for the quantitative analysis, the function of this ratio plotted against vinyl acetate content of the EVA films being a convex hyperbola. The technique was simple and rapid and did not require a complicated sample preparation procedure. 11 refs. EASTERN EUROPE; HUNGARY

Accession no.748436 Item 73 Applied Spectroscopy 53, No.8, Aug.1999, p.919-26 TWO-DIMENSIONAL NEAR-INFRARED CORRELATION SPECTROSCOPY STUDIES ON COMPOSITION-DEPENDENT SPECTRAL VARIATIONS IN ETHYLENE/VINYL ACETATE COPOLYMERS: ASSIGNMENTS OF BANDS DUE TO ETHYLENE UNITS IN AMORPHOUS, DISORDERED, AND ORTHORHOMBIC CRYSTALLINE PHASES Yanzhi Ren; Shimoyama M; Ninomiya T; Matsukawa K; Inoue H; Noda I; Osaki Y Kwansei-Gakuin,University; Hyogo,Prefectural Police Headquarters; Osaka Municipal Technical Research Institute; Procter & Gamble Co. Results of the above studies are presented and discussed in relation to the potential of three powerful techniques, i.e. two-dimensional correlation analysis, the calculation of the second derivatives and calculation of regression coefficients in chemometrics, in examining the rather complex near-IR spectra. 22 refs. JAPAN; USA

Accession no.748410 Item 74 Journal of Applied Polymer Science 73, No.14, 29th Sept.1999, p.2837-47

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References and Abstracts

FTIR QUANTITATIVE CHARACTERIZATION OF CHEMICALLY MODIFIED POLYPROPYLENES CONTAINING SUCCINIC GRAFTED GROUPS Garcia-Martinez J M; Laguna O; Areso S; Collar E P Instituto de Ciencia y Tecnologia de Polimeros The grafting of succinic anhydride onto PPs was evaluated quantitatively by FTIR spectroscopy. The relative absorbance values obtained from the IR spectra were correlated with grafting levels of the sample as determined by an improved traditional hot titration method. The results obtained appeared to be valid for either atactic or isotactic modified PPs and suggested that a careful review should be conducted of the use of this technique in the quantification of polar groups grafted onto polyolefins. 37 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; SPAIN; WESTERN EUROPE

Accession no.747390 Item 75 Journal of Applied Polymer Science 73, No.8, 22nd Aug.1999, p1569-77 UV CURING OF SURFACE COATING SYSTEM CONSISTING OF CYCLOALIPHATIC DIEPOXIDE-ENR-GLYCIDYL METHACRYLATE BY CATIONIC PHOTOINITIATORSCHARACTERIZATION OF THE CURED FILM BY FTIR SPECTROSCOPY Kumar R N; Woo C K; Abusamah A Malaysia,Science University Films were cast from a system consisting of a cycloaliphatic diepoxide, epoxidised natural rubber (ENR), glycidyl methacrylate (GMA) and a cationic photoinitiator, triphenylsulphonium hexafluoroantimonate. The films were cured by UV radiation, and characterised using Fourier transform infrared spectroscopy. It was determined that the acrylic double bonds, the epoxy groups of GMA, the isoprene double bonds, the epoxy groups of ENR, and the epoxy groups of the cycloaliphatic epoxide resin all participated in the photoinitiated polymerisation and crosslinking reactions resulting in an interpenetrating polymer network. 21 refs. MALAYSIA

Accession no.744182 Item 76 Journal of Vinyl and Additive Technology 5, No.2, June 1999, p.81-6 FOURIER TRANSFORM INFRARED MICRO SPECTROSCOPY MAPPING STUDIES OF WEATHERED PVC CAPSTOCK TYPE FORMULATIONS. II. OUTDOOR WEATHERING IN PENNSYLVANIA Garcia D; Black J

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Elf Atochem NA FTIR micro spectroscopy, coupled with mapping techniques, was shown to be an effective method for evaluating dimensionally-dependent changes such as those encountered in PVC weathering processes. The method was based on the complexity and specificity of the IR spectrum and the dimensional resolution of the microscope. A systematic FTIR study was conducted of changes observed during outdoor photodegradation of PVC siding capstock formulations, as a function of exposure time and titanium dioxide level. The results were compared with previously-obtained accelerated QUV data. Profiles through the thickness dimension were analysed to identify degradation species and depth distribution. 14 refs. USA

Accession no.743282 Item 77 Polymer Recycling 3, No.4, 1997/1998, p.287-93 QUALITATIVE AND QUANTITATIVE CHARACTERISATION OF MIXED POLYMERS USING NEAR-INFRARED-SPECTROSCOPY (NIR) Michaeli W; Plessmann K W; Andrassy B; Breyer K; Laufens P IKV; Aachen,University of Technology Details are given of an experimental technique, (the PLS2 method), which has been developed to determine the composition of mixed polymers using the NIR technique as a tool for the quality control of recycled plastics. PP/ polystyrene blends were quantitively analysed, and the effects of aluminium and paper contaminants were evaluated. 9 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.742800 Item 78 ACS Polymeric Materials Science & Engineering.Volume 80.Conference proceedings. Anaheim, Ca., Spring 1999, p.556-7 IN-SITU FTIR INVESTIGATION ON CHAIN CONFORMATION CHANGE UPON HEATING FOR PAUCI-CHAIN POLYSTYRENE MICROSPHERE MADE BY MICROEMULSION POLYMERIZATION Weihua Ming; Yiqiang Zhao; Jun Zhao; Shoukuan Fu; Jones F N Fudan,University; Eastern Michigan,University (ACS,Div.of Polymeric Materials Science & Engng.) Polystyrene microspheres, produced by microemulsion polymerisation, generally contain only one or a few polymer chains, and may thus be termed single- or pauci-

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chain microspheres. Changes in chain conformation on heating were studied using in-situ Fourier transform infrared spectroscopy. Discontinuities in the relationship between peak height and temperature were attributed to the glass transition and changes in the phenyl ring stretch mode due to the formation of phenyl ring stacking. 12 refs. CHINA; USA

Accession no.742138 Item 79 Polymer Bulletin 42, No.5, May 1999, p.579-86 RHEO-OPTICAL FOURIER TRANSFORM INFRARED SPECTROSCOPY OF DIOLMODIFIED DIGLYCIDYL ETHER OF BISPHENOL-A EPOXY RESINS Scherzer T Leipzig,Institut fuer Oberflachenmodifizierung

POST-CONSUMER PLASTIC IDENTIFICATION USING RAMAN SPECTROSCOPY Allen V; Kalivas J H; Rodriguez R G Idaho,State University The suitability of Raman spectroscopy, when used with K-nearest neighbours, library searching or cyclic subspace regression, for computerised classification of postconsumer plastics was evaluated. Plastics investigated were PETP, PP, PS, PVC, HDPE AND LDPE. Modifications were made to the original cyclic subspace regression algorithm for modelling multiple sample properties and the adapted algorithm employed to directly compare the mechanisms of principal component regression and the PLS2 form of partial least-squares. It was found that Raman spectroscopy could be used to identify both HDPE and LDPE. 33 refs. USA

Accession no.741260

Diol-modified epoxy resins were prepared from bisphenol A diglycidyl ether modified with alpha,omega-diols of different chain lengths and at different molar ratios. the molecular orientation of the epoxy networks was investigated using rheooptical FTIR spectroscopy and uniaxial deformation was carried out above and below the glass transition temperature. The effects of diol chain length and molar ratio on the mechanical properties and orientation parameter were discussed. 17 refs.

Item 82 Applied Spectroscopy 53, No.5, May 1999, p.557-64 COMPARISON OF NEAR-INFRARED AND RAMAN SPECTROSCOPY FOR THE DETERMINATION OF CHEMICAL AND PHYSICAL PROPERTIES OF NAPHTHA Min-Sik Ku; Hoeil Chung SK Corp.

EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Near-infrared and FTIR Raman spectroscopy were compared and evaluated for the quantitative analysis of naphtha using partial least-squares regression. 19 refs.

Accession no.741938 Item 80 Applied Spectroscopy 53, No.6, June 1999, p.682-6 IN SITU ANALYSIS OF A HIGH TEMPERATURE CURE REACTION IN REAL TIME USING MODULATED FIBRE-OPTIC FT-RAMAN SPECTROSCOPY Aust J F; Cooper J B; Wise K L; Jensen B J Old Dominion University; US,NASA,Langley Research Center The high temperature (330C) cure reaction of 4-phenoxy4'-phenylethynylbenzophenone was monitored using a modulated fibre-optic Fourier transform-Raman spectrometer. Spectral evidence for two different reaction pathways (cyclisation and chain extension) is provided. The formation of a conjugated double bond system of varying chain lengths is indicated. 19 refs. USA

Accession no.741261 Item 81 Applied Spectroscopy 53, No.6, June 1999, p.672-81

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Accession no.740339 Item 83 ACS, Polymeric Materials Science and Engineering. Vol.76. Conference proceedings. San Francisco, Ca., Spring 1997, p.191-2. 012 TOWARDS A BETTER UNDERSTANDING OF SEGMENTAL MOBILITY IN POLYMERS UNDER EXTERNAL PERTURBATIONS: TIMERESOLVED FTIR-STUDIES Ameri A; Ekgasit S; Hendann C; Michel S; Wu P; Okretic S; Pfeifer F; Zebger I; Siesler H W Essen,University (ACS,Div.of Polymeric Materials Science & Engng.) The elucidation of the mechanisms and dynamics of segmental mobility in polymers under the influence of external perturbations can tremendously contribute to the improvement of certain manufacturing processes or to the optimisation of the engineering properties of technically important polymeric materials. Application of a uniaxial or bidirectional elongation, on the other hand, is a common pretreatment of a polymeric material to improve its mechanical end-use properties. Generally, time-

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References and Abstracts

resolved IR spectroscopy has proved an extremely valuable tool to investigate the structural details of molecular changes incurred by a polymer under the influence of such an external perturbation. The elucidation of the transient molecular changes during polymer deformation is an important issue in polymer processing. In the film forming process, an amorphous sheet is cast from the melt onto a cooled drum, followed by sequential forward and sideways drawing at different temperatures and heat setting in ovens. The ability to monitor and model such drawing and relaxation processes would benefit greatly product quality and web efficiency. Rheo-optical FTIR spectroscopy is one of the few techniques providing data on the crystallisation, orientation and conformational changes of a polymer during mechanical treatment. To emphasise the potential of the technique, selected examples of rheo-optical measurements on industrially relevant thermoplastic and elastomeric polymers are presented and interpreted in terms of their deformation, recovery and relaxation mechanisms. Where applicable, 2D-correlation analysis is utilised to enhance the information derived from the vibrational spectroscopic data. 3 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.737971 Item 84 Polymer 40, No.17, 1999, p.4723-31 INFRARED AND RAMAN SPECTROSCOPY OF CYCLOHEXA(P-PHENYLENE SULPHIDE) AND THE POLYMER OBTAINED THEREFROM Zimmerman D A; Koenig J L; Ishida H Case Western Reserve University Cyclohexa(p-phenylene sulphide) (CHPS) was studied as a precursor of poly(p-phenylene sulphide) (PPS). The FTIR and Raman spectra of CHPS were found to resemble those of amorphous PPS closely. Specific modes indicative of the crystal structure and band shifts were reported. A crystal structure change in CHPS which was induced by pressure or heat was identified. Polymerisation of CHPS was carried out and the polymerised CHPS showed a slightly higher crystallinity than that of commericial low molecular weight PPS with minimal branching. 23 refs. USA

Accession no.737357 Item 85 Colloid & Polymer Science 277, No.4, April 1999, p.376-81 FOURIER TRANSFORM INFRARED STUDY OF THE PHASE TRANSITION IN AQUEOUS SOLUTIONS OF ETHYLENE OXIDEPROPYLENE OXIDE TRIBLOCK COPOLYMER

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Guo C; Liu H Z; Chen J Y Chinese Academy of Sciences The phase transition between unimer and micellar phases of polyethylene oxide-polypropylene oxide-polyethylene oxide) (PEO-PPO-PEO) triblock copolymer Pluronic P105 in aqueous solution is investigated as a function of temperature using Fourier transform infrared spectroscopy. The transition of 8 wt.% Pluronic P105 in aqueous solution is found to occur at 25 deg.C. As the temperature increases, PO blocks appear to be stretched conformers with strong interchain interaction, and the formation of a hydrophobic core in the micellar phase. The EO chains are found to change to a more disordered structure with low-chain packing density from the unimer phase to the micellar phase. Both the EO and PO blocks exhibit dehydration during the phase transition. 20 refs. CHINA

Accession no.732300 Item 86 Coloring Technology for Plastics. New York, N.Y., Plastics Design Library, 1999, p.197207. 52 MEASURING STABILISERS IN PIGMENTED PLASTICS WITH NEAR-INFRARED SPECTROSCOPY Solera P; Nirsberger M; Castillo N Ciba Specialty Chemicals Corp. Edited by: Harris R M Near-infrared (NIR) spectroscopy has become a commonplace analytical tool in the plastics industry. NIR techniques have made quantification of many organic components in polymer processing easy and quick. The work presented outlines the methodology for using NIR to measure stabiliser levels in colour concentrates and natural polymer formulations. Advantages and limitations are considered as well as particle size and product form. 4 refs. USA

Accession no.732217 Item 87 Coloring Technology for Plastics. New York, N.Y., Plastics Design Library, 1999, p.1915. 52 PRACTICAL ANALYSIS TECHNIQUES OF POLYMER FILLERS BY FOURIER TRANSFORM INFRARED SPECTROSCOPY (FTIR) Coles B J; Hall C J Hauser Inc. Edited by: Harris R M The identification of polymers by FTIR is often complicated by the presence of fillers. However, for kaolin clay, FTIR analysis should be able to identify the filler and predict its

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concentration using a standard curve. The resulting percentage is more reliable than a simple ash, which may change the chemical composition of the filler. 2 refs. USA

Accession no.732216 Item 88 Macromolecules 32, No.8, 20th April 1999, p.2748-60 FTIR IMAGING STUDIES OF A NEW TWO-STEP PROCESS TO PRODUCE POLYMER DISPERSED LIQUID CRYSTALS Bhargava R; Shi-Qing Wang; Koenig J L Case Western Reserve University A method for reducing liquid crystal solubility in production of polymer dispersed liquid crystals(PDLCs) was developed which involved cooling a homogeneous liquid crystal/precursor matrix into the two-phase regime, followed by fast matrix polymerisation. The proposed procedure was tested by using a well-studied PDLC system, NOA65 (a UV-curable optical adhesive) and E7 (a mixture of cyanobiphenyls). Liquid crystal remaining dissolved in the matrix was sharply reduced by this method. Residual solubility of the matrix material in liquid crystal domains was also decreased. While maintaining the same phase composition, the method also allowed tailoring dispersion size according to needs as opposed to the invariable correlation between droplet size, solubility and polymerisation rate inherent in the classical polymerisation-induced phase separation methods. This general methodology could be usefully applied to other systems. FTIR imaging, combined with statistical methods, was shown to be a valuable tool for determining phase composition in multiphase systems. 49 refs. USA

Accession no.731938 Item 89 Macromolecules 32, No.8, 20th April 1999, p.2684-9 CONFORMATIONALLY SENSITIVE INFRARED VIBRATIONS OF THE SYNDIOTACTIC POLYSTYRENE/ETHYLBENZENE COMPLEX Moyses S; Spells S J Sheffield,Hallam University The 920 to 960/cm region of the IR spectrum of the delta phase syndiotactic PS/ethylbenzene predominantly involved bands arising from helical structures and was studied as a function of heating temp. Curve fitting and deconvolution showed the necessity, for annealing temps. above 120C, of adding a third component at 940/cm to peaks at 934 and 943/cm. The 934 and 943/cm peaks behaved as a doublet, primarily due to the delta phase, with the splitting increasing on annealing. The 940/cm peak was solely due to the gamma phase helix. These assignments provided the opportunity for using these bands for further

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studies of complexation/decomplexation in such systems. The reduction in absorbance of 934 and 943/cm peaks occurred at a lower temp. than the rise in the 940/cm absorbance and this was attributed to disordering of the delta phase helices prior to reformation as gamma phase helices. Similar measurements using deuterated syndiotactic PS also showed helix and zigzag bands, but without a predominantly delta phase helix peak. Solvent peaks in the deuterated syndiotactic PS/ethylbenzene system were used to monitor the delta to gamma phase transition. In combination with DSC and TGA data, the m.p. of the alpha phase was found to be depressed by 7C for the deuterated polymer, while the delta to gamma phase temp. was shown to be about 24C higher. 26 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.731930 Item 90 Polymer Preprints. Volume 40. Number 1. March 1999. Conference proceedings. Boston, Ma., March 1999, p.627-8. 012 ELUCIDATION OF CRYSTALLINE STRUCTURE IN POLYETHYLENE TEREPHTHALATE BY EXTERNAL REFLECTION INFRARED SPECTROSCOPY Cole K C; Ajji A; Pellerin E Canada,National Research Council (ACS,Div.of Polymer Chemistry) Despite countless studies of the microstructure of PETP and its relationship to process conditions and properties, the complex behaviour of this polymer is not fully understood. While it is clear that it cannot be described in terms of a simple two-phase (amorphous-crystalline) model, the nature of the third or intermediate phase is not easy to define. The morphology of the ‘strain-induced crystalline’ material produced by drawing amorphous PETP is different from that of material obtained by thermal crystallisation. Furthermore, it has been shown that thermal crystallisation involves two distinct stages. The primary stage starts to become significant around 90 deg.C not far above the glass transition temperature, and shows a sigmoidal dependence on log (time). The secondary stage becomes significant only above about 140 deg.C and shows a linear dependence on log (time). Front-surface reflection IR spectroscopy is used to characterise the structure of drawn samples. This approach is particularly interesting because it provides the complete IR spectrum, including the highly absorbing bands that are often saturated in transmission spectra. Significant differences between samples with strain-induced crystallinity and one that was thermally crystallised are observed. The study is extended to samples thermally crystallised over a wider range of conditions, in order to better understand the phenomena that govern the crystallisation of PETP. 4 refs. CANADA

Accession no.730486

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References and Abstracts

Item 91 ACS Polymeric Materials Science & Engineering. Volume 74. Conference proceedings. New Orleans, La., Spring 1996, p.266-7. 012 CRACK ANALYSIS OF UNFILLED NATURAL RUBBER USING INFRARED MICROSPECTROSCOPY Neumeister L A; Koenig J L Case Western Reserve University (ACS,Div.of Polymeric Materials Science & Engng.) The fatigue of natural and styrene-butadiene rubbers is an enormous industrial problem, as important mechanical properties of these materials deteriorate quickly when stressed. Although fatigue may describe the deterioration of certain material properties, it is generally believed that the term also describes failure by cracking. In fact, abrasive wear is due to the cumulative growth of cracks by tearing under repetitive loading. Therefore, the analysis and characterisation of cracks in NR are crucial to the development of material with improved fracture resistant properties. Several spectroscopic methods are available for characterising the crack tip region of the rubber on the molecular scale. Attenuated total reflectance or ATRIR has been used to characterise the structure of many different polymers. For example, it has been used to characterise the structure of 1,2-polybutadiene as well as to study the reactions of polymers. Transmission has also been well established as a viable technique for the molecular characterisation of transparent materials including thin films of unfilled NR. Again the spectra can be used for quantitative and qualitative experimentation and analysis. 7 refs. USA

Accession no.724898 Item 92 International Symposium on Orientation of Polymers: Application to Films and Fibres. Retec proceedings. Boucherville, Qc., 23rd-25th Sept.1998, p.573-74. 8(11)32 MOLECULAR ORIENTATION AND RELAXATION STUDIES OF POLYMERS USING POLARISATION MODULATION INFRARED SPECTROSCOPY Pellerin C; Vrabie D G; Duchesne C; Bazuin C G; Brisson J; Pezolet M; Prud’homme R E Quebec,Universite Laval (SPE; NRC/IMI) The apparatus is described and details given of its use with PETP homopolymer, PS/poly(vinyl methyl ether) miscible blend and styrene-styrenesulphonic acid copolymer/ethyl acrylate-4-vinylpyridine copolymer ionomer blend with ionic interactions. Orientation and relaxation curves were obtained for all three samples. It is concluded that the technique is very efficient for obtaining curves with high precision. For these three systems, the relaxation rate increases with temperature.

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For PETP, a reorientation as a function of time was observed. This phenomenon is dependent on temperature and draw ratio, and is probably due to the crystallisation of the sample. For the PS/poly(vinyl methyl ether) blend, the addition of poly(vinyl methyl ether) to the blend increased the orientation of the PS chains during the stretching. For the ionomer blends, the orientation of both types of chain was higher when the ionic content increased. 4 refs. CANADA

Accession no.724352 Item 93 Polymer 40, No.10, 1999, p.2619-24 THERMAL MICRO ATR/FT-IR SPECTROSCOPIC SYSTEM FOR QUANTITATIVE STUDY OF THE MOLECULAR STRUCTURE OF POLY(NISOPROPYLACRYLAMIDE) IN WATER Shan-Yang Lin; Ko-Shao Chen; Liang Run-Chu Taipei,Veterans General Hospital; Tatung,Institute of Technology A newly developed thermal micro attenuated total reflection (ATR)/FTIR spectroscopic system with curve fitting program was used for the quantitative investigation of molecular interactions in aqueous solutions of poly(Nisopropylacrylamide) (PNIPAAM). The lower critical solution temperature (LCST) in water of the PNIPAAM studied was found to be about 33C by cloud point measurement, DSC and the thermal micro ATR/FTIR spectroscopic system. The results from the new spectroscopic system with curve fitting program indicated that intermolecular interactions might predominate between PNIPAAM and water at temperatures below the LCST but above the LCST, PNIPAAM molecules in water were aggregated because of intramolecular interactions within the PNIPAAM molecules and the hydrophobic interactions in the system. 35 refs. TAIWAN

Accession no.724062 Item 94 Polymer 40, No.10, 1999, p.2569-86 MORPHOLOGICAL CHARACTERISATION OF THE CRYSTALLINE STRUCTURE OF COLDDRAWN HDPE USED AS A MODEL MATERIAL FOR THE ENVIRONMENTAL STRESS CRACKING (ESC) PHENOMENON Lagaron J M; Dixon N M; Reed W; Pator J M; Kip B J DSM Research; BP Chemicals; Valladolid,Universidad Micro-Raman spectroscopy was used in conjunction with mechanical deformation to study the structural changes which occur in the cold drawing of HDPE. The cold drawn structure was highly orientated and a large

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References and Abstracts

decrease in the Raman orthorhombic crystallinity was seen. The results indicated an ill-defined orthorhombic crystalline structure with dislocations and disrupted crystals formed by cold drawing, possibly resulting from molecules being pulled through the crystals. In-situ Raman straining experiments, carried out on cold drawn HDPE at 240K, showed that further orthorhombic crystalline disruption occurred with strain. No disruption was observed in fibrils created during environmental stress crack resistance tests at 348K. Temperature was an important parameter in the crystalline phase recovery of the orthorhombic crystallinity and when the cold drawn HDPE was annealed, the monoclinic phase disappeared. 47 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; NETHERLANDS; SPAIN; UK; WESTERN EUROPE

Accession no.724059 Item 95 ACS Polymeric Materials Science & Engineering, Spring Meeting 1998. Volume 78. Conference proceedings. Dallas, Tx., Spring 1998, p.24. 012 ANALYSIS OF A POLYURETHANE ELASTOMER USING THERMAL 2D FT-IR Graff D K; Wrobleski D A; Marsh A L; Kober E M; Smith M E; Schnoover J R Los Alamos National Laboratory (ACS,Div.of Polymeric Materials Science & Engng.) PU-polyester elastomers contain hard and soft domains which give these materials unique structural and elastic properties and lead to their use in various applications. It is desirable to characterise the molecular level interactions giving rise to the two domains, and to use this information to monitor chemical changes which take place in the polymer as a function of exposure to agents known to effect structural changes. IR spectroscopy has been used to study polymeric structures, including PU elastomers, as the vibrational absorption bands characteristic of different functional groups are sensitive to changes in their chemical environment. One difficulty in the application of IR spectroscopy to complex chemical systems has been the ambiguity of interpretation due to the limitations of different deconvolution techniques. The development of a 2D correlation method has provided a means by which convoluted spectral information, such as that arising from the two domains of estane, can be resolved as a function of some perturbation. A thermal 2D FT-IR study of estane is presented. 2 refs. USA

Accession no.719142 Item 96 ACS Polymeric Materials Science & Engineering, Spring Meeting 1998. Volume 78. Conference proceedings. Dallas, Tx., Spring 1998, p.22-3. 012

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DYNAMIC OPTO-RHEOLOGICAL STUDY OF ESTANE COPOLYMERS USING STEP-SCAN FTIR SPECTROSCOPY Wang H; Palmer R A; Graff D K; Schoonover J R Duke,University; Los Alamos National Laboratory (ACS,Div.of Polymeric Materials Science & Engng.) Urethane copolymers generally consist of linear segments of PU and polyester (or polyether). At room temperature, these polymers undergo a microphase separation, in which the PU segments form hard domains while the polyester segments form relatively soft domains that act as the crosslinks between the hard cores. This morphology provides such copolymers distinctive thermal and mechanical properties which have led to an extensive range of applications. A wide variety of techniques has been utilised to characterise the microscopic (molecular) structure of polymeric materials, including those of PUs and urethane copolymers, since the knowledge of the microscopic structure of these polymers is critical to the understanding of their macroscopic properties. Recently, a dynamic infrared opto-rheological method has been developed which involves the combination of dynamic mechanical analysis and time-resolved IR spectroscopy to study the real time IR spectral changes in polymer films under sinusoidal (or impulse) tensile stress of small amplitude. Phase-locked electronics are used to record the dynamic infrared spectral change in-phase and inquadrature with the applied mechanical field. The result provides insight to the response to the external stress on the molecular and submolecular scale. While for relatively narrow spectral ranges this experiment is efficiently carried out by use of a dispersive spectrometer, for measurements over broader spectral windows, the use of step-scan Fourier transform IR (S2FT-IR) has proved to be more effective. Dynamic opto-rheology using S2FTIR spectroscopy is applied to the urethane-ester copolymer Estane 5703. Dynamic in-phase and quadrature spectra in the mid-IR region at two orthogonal polarisations are collected, and dynamic dichroic spectra calculated and interpreted. 18 refs. USA

Accession no.719141 Item 97 ACS Polymeric Materials Science & Engineering, Spring Meeting 1998. Volume 78. Conference proceedings. Dallas, Tx., Spring 1998, p.20-1. 012 STEP SCAN PHOTOACOUSTIC FT-IR SPECTROSCOPY AND STRATIFICATION PROCESSES IN THERMOPLASTIC OLEFINS (TPO) Stegge J M; Urban M W North Dakota State University (ACS,Div.of Polymeric Materials Science & Engng.) The majority of methods used for analysis of complex systems such as thermoplastic olefins (TPO) are

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References and Abstracts

destructive. The technique that offers non-destructive features and allows probing surfaces on a molecular level for interactions is step-scan photoacoustic FT-IR (S2 PAS FTIR) spectroscopy. Although step-scan photoacoustic FTIR experiments can be used to collect information from selectable and constant depths from the sample surface, a possible limitation arising from this experiment is the contamination of the signal from sample areas above the sampling depth. In order for a signal to be produced the heat generated must travel completely through the sample from the depth of origin to the sample surface. In an effort to overcome this limitation it is beneficial to spread the spectral information out over another dimension. This can be accomplished by introducing a time dependence to the signal detection, and monitoring the sample response to a perturbation. While various external perturbations, including mechanical, thermal and magnetic field variation, have been employed or suggested to induce time dependence into a system, internal perturbations such as the photothermal effect have been mostly neglected or unrecognised. Through the use of this type of perturbation a two-dimensional correlation analysis can be used to gain increased spectral resolution or investigate component interaction. 12 refs. USA

Accession no.719140 Item 98 ACS Polymeric Materials Science & Engineering, Spring Meeting 1998. Volume 78. Conference proceedings. Dallas, Tx., Spring 1998, p.18-9. 012 MULTI-DIMENSIONAL SURFACE AND INTERFACIAL ANALYSIS OF POLYMERS AND COATINGS; ATR, STEP-SCAN PHOTOACOUSTIC, FT-IR/FT-RAMAN IMAGING Urban M W North Dakota State University (ACS,Div.of Polymeric Materials Science & Engng.) Vibrational spectroscopy represents two physically different, yet complementary spectroscopic techniques: IR and Raman spectroscopy. Although both methods have been utilised for many years, recent advances in electronics, computer technologies and sampling made Fourier transform infrared (FTIR) and Raman (FTRaman) one of the most powerful and versatile analytical tools. Enhanced sensitivity and surface selectivity allows non-invasive, no-vacuum molecular level analysis of surface and interfaces. Emphasis is placed on recent advances in attenuated total reflectance (ATR), step-scan photoacoustic (SS-PA), Fourier transform infrared (FTIR) and FT-Raman microscopies, as utilised to the analysis of polymeric surfaces and interfaces. A combination of these probes allows detection of molecular level changes responsible for macroscopic changes in three dimensions from various depths. 7 refs.

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USA

Accession no.719139 Item 99 Polymer 40, No.7, 1999, p.1629-36 ROLE OF AN ACTIVE ENVIRONMENT OF USE IN AN ENVIRONMENTAL STRESS CRACK RESISTANCE (ESCR) TEST IN STRETCHED POLYETHYLENE: A VIBRATIONAL SPECTROSCOPY AND SEM STUDY Lagaron J M; Pastor J M; Kip B J DSM Research; Valladolid,Universidad The role of an environmental stress crack resistance (ESCR) detergent (active environment) during tensile deformation of PE samples was studied using Raman and IR spectroscopy. Raman spectroscopy was found not to be suitable for detecting this environment inside the sample, but IR spectroscopy indicated that the environment was predominantly present within the transition fronts of the material. A stress-induced environment diffusion mechanism was suggested. SEM showed differences in the deformation process between drawing in air or in detergent. The results indicated that the environment penetrated the sample during the necking process and stabilised crazing. The molecular mechanisms were discussed. 14 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; NETHERLANDS; SPAIN; WESTERN EUROPE

Accession no.714041 Item 100 ACS Polymeric Materials Science and Engineering. Fall Meeting 1998. Volume 79. Conference proceedings. Boston, Mas., 23rd-27th Aug.1998, p.506-7. 012 INFRARED SPECTROSCOPIC STUDY OF OXIDATION IN POLYURETHANE HARD SEGMENTS Skorich S R; Benz M E Medtronic Inc. Previous studies have indicated that in vivo oxidation of polyether urethanes (PEUs) has involved depletion of the soft segment of the material . The use of an attenuated total reflectance (ATR) objective on the infrared (FTIR) microscope has allowed analysis of much smaller areas on PU tubing samples removed from in vivo implantation. By means of the micro ATR, the differences between the IR spectra of clear vs. fissured areas of PEUs are enhanced, and IR peaks typical of fissured areas are observed. Similar peaks were observed on fissured areas of a polycarbonate urethane (PCU) which shares the same hard segment with the PEUs. It became clear that the hard segment was involved in the fissuring process as well as the soft segment. Hard segments in both these materials were based on 4,4'-methylene bis diisocyanate (MDI) and

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References and Abstracts

1,4-butanediol (BDO). Two model diethyl carbamate (urethane) compounds are synthesised from 4,4'methylene dianiline and 4,4'-diaminobenzophenone. The spectra of these materials show the same sort of spectral differences as between the clear and fissured materials above. These compounds closely model the hard segment of the above materials, and differ only in the oxidation to a carbonyl group of the central methylene group in the molecule. This implies that the same process is occurring in the PU hard segments, in addition to any soft segment reactions. 6 refs. USA

Accession no.713291 Item 101 Macromolecules 31, No.25, 15th Dec.1998, p.9008-12 MOLECULAR ORIENTATION AND DYNAMICS IN FERROELECTRIC DIBLOCK COPOLYMERS MONITORED BY FTIR SPECTROSCOPY Merenga A; Shilov S V; Kremer F; Mao G; Ober Ch K; Brehmer M Leipzig,University; St.Petersburg,Institute of Macromol.Compounds; Cornell University; Wuppertal,Bergische Universitaet In ferroelectric liquid crystalline block copolymers the properties of ferroelectric liquid crystals are combined with those of diblock copolymers. Hence, one observes in these materials a microphase separation between the amorphous polymer (PS) and the ferroelectric liquid crystal segment (a side chain containing oxybiphenylene nitrooxybenzoate groups). The latter group can be switched by applying an external electric field. Time resolved FTIR was used to study structure and dynamics of these systems. From analysis of the dichroism of the FTIR spectra, it was concluded that the components in the PS microphase are oriented randomly while the liquid crystalline groups form an ordered phase. Time-resolved measurements of the switching of the liquid crystalline block were performed during the application of an external electric field. It may be shown that switching is of an electroclinic type and that the tilt angle and the mesogenic motion increase with temperature, especially if the PS block is heated above Tg. The orientation of the liquid crystalline block after heating to the isotropic phase is completely restored due to the memory effect of the polymer microstructure. 12 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; RUSSIA; USA; WESTERN EUROPE

Accession no.711651 Item 102 European Polymer Journal 34, No.11, Nov.1998, p.1571-7 DYNAMIC INFRARED SPECTROSCOPY, A TOOL TO DETECT HYDROGEN BONDS IN POLYMERS?

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Kischel M; Kisters D; Strohe G; Veeman W S Gerhard-Mercator Universitat Dynamic infrared linear polarised spectra of thermoplastic polyester urethane and nylon-6 films were recorded under a varying sinusoidal strain. Dichroic spectra were calculated from the dynamic polarised spectra. The large bipolar bands in the dichroic in-phase spectra, caused by large frequency shifts of the original monopolar absorption bands, were ascribed to hydrogen bonds. 29 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.709540 Item 103 Polymer 40, No.5, March 1999, p.1131-7 POLYMERIZATION OF HYDROXYALKYL METHACRYLATES CHARACTERIZED BY COMBINATION OF FT-RAMAN AND STEPSCAN FT-I.R. PHOTOACOUSTIC SPECTROSCOPY Kammer S; Albimsky K; Sandner B; Wartewig S Halle,Martin-Luther-Universitat The free radical polymerisation of 2-hydroxyethyl methacrylate was studied by FT-Raman spectroscopy and that of bisphenol-A-bis(2-hydroxypropyl methacrylate) was studied by this technique and also by FTIR photoacoustic spectroscopy. Raman spectroscopy was used to determine the conversion of C=C double bonds of the monomers exactly. 18 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.707124 Item 104 Polymer Degradation and Stability 62, No.2, 1998, p.395-401 OXIDATION OF RUBBERS ANALYSED BY HORIZONTAL ATR/IR SPECTROSCOPY Delor F; Barrois-Oudin N; Duteurtre X; Cardinet C; Lemaire J; Lacoste J Blaise Pascal,Universite; Renault; Hutchinson The analysis of rubbers containing large amounts of carbon black by IR spectroscopy is difficult, particularly studies of their chemical evolution upon ageing. The use of a horizontal ATR accessory equipped with a germanium crystal is described. Horizontal ATR(Ge)/FTIR analysis of both thermal- and photooxidations of EPDM, polychloroprene and NBR were first validated by conventional transmission spectroscopy in the absence of carbon black. Horizontal ATR(Ge) was then used with fully formulated rubbers with the aim of studying their long-term behaviour. The effects of temp., UV exposure, carbon black or stress as well as the oxidation profile across the materials on

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References and Abstracts

the identification of carboxylic acid/carboxylate groups were examined. 8 refs.

the spatially specific compositional heterogeneity could be easily identified. 18 refs.

EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; WESTERN EUROPE

JAPAN

Accession no.706569 Item 105 Analytical Chemistry 70, No.22, 15th Nov.1998, p.4701-8 SIMULTANEOUS MULTISPECTRAL IMAGING IN THE VISIBLE AND NEAR-INFRARED REGION: APPLICATIONS IN DOCUMENT AUTHENTICATION AND DETERMINATION OF CHEMICAL INHOMOGENEITY OF COPOLYMERS Tran C D; Yan Cui; Smirnov S Marquette,University

Accession no.704051 Item 107 Polymer Analysis and Characterization. V. Applied Polymer Symposium proceedings. Inuyama, 1st-4th June 1992, p.55-62. 91T TWO-DIMENSIONAL INFRARED STUDIES OF SUBMOLECULAR LEVEL DYNAMICS OF POLYMERS Noda I; Dowrey A E; Marcott C Procter & Gamble Co. (ISPAC) Applied Polymer Symposium 52

A multispectral imaging spectrometer capable of simultaneously recording spectral images in the visible and near-IR was developed. In this instrument, an acoustooptic tunable filter was used to diffract beams with orthogonal polarisation, one of them being detected by a silicon camera for the visible region, while the other beam was detected in the near-IR region with a near-IR camera. Preliminary applications of the imaging spectrometer included measurements of the visible and near-IR absorption spectra of ink used to print U.S. currency and studies of EVA copolymers. The near-IR spectral images obtained clearly indicated that the EVA copolymers exhibited a high degree of chemical inhomogeneity. 22 refs.

Two-dimensional infrared (2D IR) spectroscopy is used to elucidate the submolecular-level dynamics of an amorphous polymer under a dynamic deformation. In 2D IR, a polymer sample is perturbed by a small-amplitude oscillatory strain, and the resulting dynamic fluctuation of IR signals is used to construct a set of 2D correlation maps. These 2D maps are especially suited for obtaining detailed information about local dynamics of submolecular constituents of the system. 2D IR spectra of glassy atactic PS reveal that while the mainchain backbone reorients in the direction of applied strain, there also exist highly localised reorientational motions of phenyl side groups occurring independently of the mainchain realignment. This localised submolecular distortion is not strongly observed at temperatures well above the glassto-rubber transition. 6 refs.

USA

USA

Accession no.704919

Accession no.704035

Item 106 Polymer Analysis and Characterization. V. Applied Polymer Symposium proceedings. Inuyama, 1st-4th June 1992, p.251-9. 91T CHARACTERISATION OF COATED INTERFACES AND POLYMER BLENDS USING FOURIER TRANSFORM INFRARED MICROSPECTROSCOPY Nishioka T; Teramae N Idemitsu Petrochemical Co.Ltd. (ISPAC) Applied Polymer Symposium 52

Item 108 Synthetic Metals 96, No.1, 15th July 1998, p.63-70 SERS SPECTRA OF POLYANILINE THIN FILMS DEPOSITED ON ROUGH AG, AU AND CU. POLYMER FILM THICKNESS AND ROUGHNESS PARAMETER DEPENDENCE OF SERS SPECTRA Baibarac M; Cochet M; Lapkowski M; Mihut L; Lefrant S; Baltog I Rumania,National Institute of Material Physics; Nantes,Institut des Materiaux; Silesian Technical University

Fourier transform infrared microspectroscopy is applied for the characterisation of a coated interface and a polymer blend. The coated sample investigated is prepared by coating a urethane paint on an ethylene-ethyl acrylate copolymer whose ethyl-ester group is partially hydrolysed (EAA/EEA). It is demonstrated that a mixed phase is formed along the coated interface between the paint and the EAA/EEA. Interaction between molecules of the urethane paint and the EAA/EEA is observed. For a polymer blend prepared by mixing PP and polycarbonate,

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SERS spectra under 1064 nm excitation were studied for two forms of polyaniline, one of the emeraldine base type and the other of the emeraldine salt type to identify the chemical effects at the polymer/metal interface that are involved in the specific modifications of the SERS spectra. 19 refs. EASTERN EUROPE; EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; POLAND; RUMANIA; WESTERN EUROPE

Accession no.703351

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References and Abstracts

Item 109 International Composites Expo ’98. Conference proceedings. Nashville,Tn., 19th-21st Jan.1998, Session 21-D. 627 UTILISING FOURIER TRANSFER NEAR INFRARED (FT-NIR) TO MONITOR KEY CHEMICAL CHARACTERISTICS IN THE MANUFACTURE OF THERMOSET PLASTICS Landis L P; Cameron D G Premix Inc.; DHC Analysis Inc. (SPI,Composites Institute) Thermoset plastic companies manufacture a variety of products that utilise a complex array of ingredients and process environments. In a typical thermoset plastic, there could be over ten ingredients including resins, inorganic fillers, glass fibre, inhibitors, initiators, low profile additives, flame retardants, pigments and other special additives. To help monitor and control the manufacture of thermoset plastics near IR methods and protocols have been developed which are at least ten times more precise than the wet chemical methods. Premix has been using Fourier Transform Near Infrared (FT-Near IR) in the quality assurance laboratory since 1995 to measure key quality characteristics of some raw materials as well as resultant pastes. Wet chemical techniques (e.g. Karl Fischer Titration) for certain samples have been replaced by FT-Near IR. It is a nondestructive method that can be applied on, at or in-line. It allows companies to reduce the use of costly and dangerous chemicals which are often needed in many test methods, and realise significant savings through improved process control, product quality and waste reduction. 2 refs. USA

Accession no.702072 Item 110 Applied Spectroscopy 52, No.9, Sept.1998, p.1248-52 APPLICATION OF SAPPHIRE FIBERS TO AN IR FIBER-OPTIC SENSOR FOR THE INVESTIGATION OF POLYMERS AT ELEVATED TEMPERATURE Goetz R; Mizaikoff B; Kellner R Vienna,University of Technology The determination of the composition of ethylenepropylene copolymers at a temp. of 200C by means of an IR fibre-optic sensor based on sapphire fibres was studied. LDPE and PP were also investigated. Data are presented on spectra of LDPE and PP at 200C obtained using the sensor, CH3/CH2 ratio after curve fitting versus C2 content, ratio of absorbance at 2950 and 2852/cm versus C2 content and calibration graph of multivariate calibration. 31 refs.

Item 111 Applied Spectroscopy 52, No.9, Sept.1998, p.1141-4 NEAR-FIELD RAMAN SPECTRAL MEASUREMENT OF POLYDIACETYLENE Narita Y; Tadokoro T; Ikeda T; Saiki T; Mononobe S; Ohtsu M JASCO Corp.; Kanagawa,Academy of Science & Technology Two-dimensional near-field Raman spectra and topographic images of the polydiacetylene surface were measured simultaneously by using a near-field Raman spectrometer. The spectra (located 100 nm apart) had different spectral features. The peak intensity ratio of two C:C peaks at 1520 and 1457/cm did not correlate with the topographic image and showed differences in the subwavelength scale. These differences could be interpreted as spatial differences in the number of successive bonds on the polydiacetylene surface. In contrast, the near-field Raman intensity of the C:C bond at 1457/cm correlated strongly with the topographic image. This phenomenon could be interpreted as a change in the efficiency of collecting Raman scattering light. 26 refs. JAPAN

Accession no.700289 Item 112 Journal of Applied Polymer Science 70, No.6, 7th Nov.1998, p.1221-37 PHOTOOXIDATION OF ANHYDRIDE-CURED EPOXIES: FTIR STUDY OF THE MODIFICATIONS OF THE CHEMICAL STRUCTURE Ollier-Dureault; Gosse B Schneider Electric; CNRS-LEMD The photooxidative degradation of anhydride-cured epoxies was studied using transmission Fourier transform infrared and attenuated total reflection spectroscopy. The degradation was heterogeneous, the surface being much more affected from the bulk. Epoxies containing flexibilisers, which were rich in ester groups but containing fewer phenyl groups, degraded much more rapidly during the first hours of exposure than those without flexibilisers. After 40 hours of irradiation, the disappearance rate of aromatic groups was dependent only upon their initial concentration, whilst the formation kinetics of hydroxyl groups was determined by the diffusion of oxygen into the material. The formation of hydrophilic products, acids, and alcohols was confirmed by chemical treatment, and it was concluded that their presence and high concentration at the surface could be responsible for the degradation of the insulating properties of epoxies when used as electrical insulators. 20 refs.

AUSTRIA; WESTERN EUROPE

EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; WESTERN EUROPE

Accession no.700291

Accession no.700202

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References and Abstracts

Item 113 Journal of Polymer Science : Polymer Chemistry Edition 36, No.14, Oct.1998, p.2503-12 SPECTROSCOPIC INVESTIGATIONS OF POLYACRYLONITRILE THERMAL DEGRADATION Surianarayanan M; Vijayaraghavan R; Raghavan K V India,Central Leather Research Institute; Indian Institute of Chemical Technology The thermal degradation of polyacrylonitrile was investigated using Fourier transform infrared spectroscopy, high-resolution solid-state nuclear magnetic resonance spectroscopy, pyrolysis gas chromatography, and elemental analysis. Over the temperature range 150-590C, gaseous and volatile products were produced with simultaneous stabilisation of the structure of the residual material. The principle decomposition reaction was linear polymerisation of the nitrile group, with cyclisation followed by extended conjugation being a significant exothermic process. There was no evidence of the formation of oxygencontaining chromophores. 29 refs. INDIA

Accession no.699986 Item 114 Journal of Polymer Science : Polymer Physics Edition 36, No.14, Oct.1998, p.2471-82 STRUCTURAL ANALYSIS OF POLY(3HYDROXYBUTYRATE-CO-3HYDROXYVALERATE) FIBERS PREPARED BY DRAWING AND ANNEALING PROCESSES Furuhashi Y; Ito H; Kikutani T; Yamamoto T; Kimizu M; Cakmak M Tokyo,Institute of Technology; Ishikawa,Industrial Research Institute; Akron,University Wide-angle X-ray diffraction, density, infrared dichroism and birefringence measurements were used to characterise the structure of poly(3-hydroxybutyrateco-3-hydroxyvalerate) fibres which had been prepared by drawing and annealing. Three crystalline structures were present: two orthorhombic, and the third was pseudo-hexagonal. Both negative and positive values of birefringence were observed, being dependent upon the drawing and annealing temperatures. The birefringence of the amorphous phase was positive, decreasing with an increase in the annealing temperature. It was concluded that orthorhombic crystals with the c-axis preferentially orientated perpendicular to the fibre axis, and pseudo-hexagonal crystals were preferentially formed in the drawing process, irrespective of the temperature. 15 refs. JAPAN; USA

Accession no.699617

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Item 115 5th International Conference on Polyimides - New Trends in Polyimide Science and Technology. Retec proceedings. Ellenville, N.Y., 2nd-4th Nov.1994, p.25. 43C4 FTIR AND FLUORESCENCE MONITORING OF POLYIMIDE FORMATION Wang F W; Hutton R S; Lowry R E; Wang T T US,National Inst.of Standards & Technology; AT & T Bell Laboratories; Rutgers,University (SPE,Plastics Analysis Div.; SPE,Mid-Hudson Section) FTIR and fluorescence spectroscopy are used to monitor the imidisation of a polyamic acid made from 3,3',4,4'biphenyltetracarboxylic dianhydride (BPDA) and pphenylenediamine (PDA), and fluorescence spectroscopy is used to monitor the imidisation of a polyamic acid made from 2,2-bis(3,4-dicarboxyphenyl hexafluoropropane dianhydride (6FDA) and p-phenylene diamine. A film of the polyamic acid made from BPDA and PDA is heated in a nitrogen atmosphere for one hour at 75 deg.C, and the thermal treatment is repeated at each of the temperatures from 100 to 400 deg.C in 25 deg.C increments between successive thermal treatments. After each treatment, the fluorescence and the excitation spectra of the film are taken at an excitation wavelength of 460 nm and a fluorescence wavelength of 550 nm, respectively. Extended abstract only. USA

Accession no.698382 Item 116 Polymer 39, No.26, 1998, p.6899-904 CELLULOSIC BLENDS WITH POLY(ACRYLONITRILE): CHARACTERIZATION OF HYDROGEN BONDS USING REGIOSELECTIVELY METHYLATED CELLULOSE DERIVATIVES Shin J-H; Kondo T Japan,Forestry & Forest Products Res.Inst. Fourier transform infrared (FTir) spectroscopy was used to characterise the hydrogen bonds, in terms of hydroxyl regiochemistry, in blends of cellulose materials with polyacrylonitrile (PAN). Regioselectively substituted methylcelluloses were used as the cellulose model compounds. Wide-angle x-ray diffraction studies of cast films containing more than 50 wt% cellulose showed them to be highly amorphous, attributed to interaction between the cellulose and PAN. FTir analysis showed that the hydrogen bonds in washed films were only between the C-6 position in the cellulose and the nitrile group of the PAN. This was in contrast with the as-cast films, where the residual dimethylacetamide solvent promoted additional interaction between the two polymer components, resulting in enhanced miscibility. 28 refs. JAPAN

Accession no.697798

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Item 117 Polymer 39, No.26, 1998, p.6807-17 IN SITU COMPATIBILIZATION OF POLYPROPYLENE-POLYETHYLENE BLENDS: A THERMOMECHANICAL AND SPECTROSCOPIC STUDY Tselios Ch; Bikiaris D; Maslis V; Panayiotou C Thessaloniki,University Polypropylene (PP) and low density polyethylene (LDPE) were melt blended in various proportions, with poly(propylene-g-maleic anhydride) and poly(ethyleneco-vinyl alcohol) added in equal proportions as in situ reactive compatibilisers. The compatibilisation reaction was monitored by measuring the torque increase during mixing and by Fourier transform infrared spectroscopy. Improvements in tensile strength, elongation at break and impact strength were observed for all compatibilised blends, and particularly for the blends which contained 10 wt% compatibiliser. Scanning electron microscopy and Raman spectroscopy were used to investigate the blend morphology. 71 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GREECE; WESTERN EUROPE

Accession no.697789 Item 118 RadTech ’98. Conference proceedings. Chicago, Il., 19th-22nd April 1998, p.363-74. 895 CHARACTERISATION OF RADIATION CURABLE COATINGS BY CONFOCAL RAMAN MICROSCOPY Schrof W; Beck E; Koniger R; Meisenburg U; Menzel K; Reich W; Schwalm R BASF AG (RadTech International) Increasing amounts of radiation curable materials are being used in coating films for the surface refinement of furniture, wooden floor coverings, paper etc. Confocal Raman spectroscopy is used to examine depth or lateral profiles of the crosslinking process (e.g. the reaction progress) in these coatings with a resolution of approximately 1 mu3. The potential of confocal Raman microscopy is demonstrated for the problems of the inhibition of the radical polymerisation reaction by oxygen, the limited polymerisation reaction in deep layers due to the restricted penetration of UV light (LambertBeer), the reaction in pigmented coatings and the distribution of UV stabilisers interacting with the UV curing process. 11 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

INFRARED DICHROISM AND SURFACE CONFORMATIONAL DYNAMICS OF ADSORBED POLY(DIMETHYLSILOXANE) Soga I; Granick S Illinois,University Polymer conformations at a strongly adsorbing solid surface and their evolution with elapsed time during the adsorption process were examined. Poly(dimethyl-siloxane) (weight average molecular weight 118000, polydispersity index 1.16) was allowed to adsorb onto oxidised germanium from dilute carbon tetrachloride solutions. The mean backbone orientation was found to change even after the mass adsorbed had saturated. It’s conformation was determined using IR dichroism spectroscopy in attenuated total reflection (FTIRATR). The dichroic ratio of the Si-O-Si and Si-methyl stretch vibrations showed the poly(dimethylsiloxane) backbone to be preferentially horizontal to the surface (dichroic ratio about 0.9 at early adsorption times) and to grow increasingly flattened with increasing adsorption time. However, as the adsorbed amount increased with higher solution concentrations, the average orientation was less flattened. Chain flattening during the adsorption process was also slower, the higher the adsorbed amount, reflecting molecular crowding within more densely occupied layers. During desorption into the pure solvent, the evolution of the dichroic ratio could be described by the hypothesis of a bimodal configurational distribution. 21 refs. USA

Accession no.696674 Item 120 Polymer Bulletin 41, No.2, Aug 1998, p.191-8 CHARACTERISATION OF PET/LLDPE BLENDS COMPATIBILIZED WITH DEM-GRAFTEDPOLYETHYLENE Marquez L; Sabino M A; Rivero I A Simon Bolivar,Universidad Blends of polyethylene terephthalate and linear lowdensity polyethylene were compatibilised using diethylmaleate grafted polyethylene, and characterised using Fourier transform infra-red spectroscopy, thermogravimetric analysis and scanning electron microscopy. Interactions between the components in the blends were observed, which affected the glycol sequences of the polyester and also improved the thermal oxidative stability of the blends. The introduction of the compatibiliser resulted in a particle size reduction of the dispersed phase and better adhesion between the phase and the matrix. 15 refs. VENEZUELA

Accession no.696928

Accession no.696610

Item 119 Macromolecules 31, No. 16, 11th Aug. 1998, p.5450-5

Item 121 Polymer 39, No.20, 1998, p.4735-9

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References and Abstracts

CHARACTERIZATION OF ELECTROCHEMICALLY PRODUCED TWOCOMPONENT FILMS OF CONDUCTING POLYMERS BY RAMAN MICROSCOPY Sacak M; Akbulut U; Batchelder D N Leeds,University Polyaniline/poly(N-vinyl carbazole), polypyrrole/poly(Nvinyl carbazole) and polypyrrole/polyaniline films (or reverse order of each pair in the films) were synthesised on platinum foil electrodes by sequential electrolysis. Confocal Raman microprobe spectroscopy was used to characterise both the solution sides and the electrode sides of the films. Two types of film were observed, depending on the conditions. Either the second polymer was incorporated into the initially coated layer or a doublelayer film with a well-defined interface was formed. Electrolysis of pyrrole and aniline monomer mixtures gave films rich in pyrrole when the pyrrole:aniline molar ratios were greater than 0.12. However, polymerisation of N-vinyl carbazole and pyrrole monomer mixtures gave only polypyrrole over a wide range of molar ratios. 19 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.696557 Item 122 Polymer 39, No.20, 1998, p.4723-8 ATTENUATED TOTAL REFLECTANCE CELL FOR ANALYSIS OF SMALL MOLECULE DIFFUSION IN POLYMER THIN FILMS WITH FOURIER-TRANSFORM INFRARED SPECTROSCOPY Balik C M; Simendinger W H North Carolina,State University A cell for characterising the diffusion of small molecules through thin polymer films using attenuated total reflectance (ATR) FTIR spectroscopy was described. The cell was designed to be used with precast (commercially extruded) polymer films, thus enabling the as-processed transport properties of the film to be studied. The cell was used to measure the diffusion of carbon dioxide, amyl acetate and limonene, and simultaneous diffusion of the individual components from a 50/50 mixture of amyl acetate and limonene through the thin polymer films (HDPE, LDPE and PS). Diffusion coefficients measured with the ATR technique compared favourably with values obtained from gravimetric measurements with the same penetrants and polymer samples. 20 refs. USA

Accession no.696555 Item 123 Polymer 39, No.25, 1998, p.6589-96

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CHARACTERISATION OF RANDOM PROPYLENE-ETHYLENE COPOLYMER Feng Y; Hay J N Birmingham,University The comonomer sequence in a propylene-ethylene random copolymer was investigated using temperature rising elution fractionation, nuclear magnetic resonance spectroscopy, Fourier transform infra-red spectroscopy and differential scanning calorimetry. There was a wide range of compositional heterogeneity, the composition comprising mainly long propylene sequences with an occasional ethylene unit. The sequence distributions of the fractions did not fit either Bernoulli or first order Markovian statistics. The crystallisation kinetics and melting behaviour were strongly influenced by the ethylene content and the comonomer distribution. 33 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.694681 Item 124 Polymer 39, No.25, 1998, p.6533-9 NEW ACRYLIC TITANIUM POLYMERS: II. SYNTHESIS AND CHARACTERIZATION OF ORGANOTITANIUM POLYMERS Camail M; Humbert M; Margaillan A; Vernet J L Toulon et du Var,Universite The synthesis of acrylic organotitanium polymers by the copolymerisation of acrylic organotitanium monomers with methyl methacrylate via free-radical initiation in organic solvents, or by esterification of the acid functions of an acrylic polymer with titanium tetraalkoxide, was investigated. These polymers have potential application as a marine anti-fouling coating. With a stoichiometric molar ratio of titanium:carboxyl, a gel was formed. The preparation of an esterified polymer, soluble in the usual organic solvents, required an excess of titanium tetraalkoxide. The amount of excess required depended upon the nature of the alkoxide, the concentration and the nature of the polymer. 11 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; WESTERN EUROPE

Accession no.694674 Item 125 European Polymer Journal 34, No.8, Aug.1998, p.1199-205 PREPARATION AND CHARACTERIZATION OF GRAFT COPOLYMERS OF POLYACRYLAMIDE AND POLYETHYLENIMINE Li D; Zhu S; Pelton R H McMaster University The condensation grafting of polyethylenimine (PEI) onto poly(acrylamide-co-acrylic acid) (PAM-co-AA) was studied. Fourier transform infra-red spectroscopy was

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used to investigate the reaction mechanism, which proceeded by a two-step reaction, involving the conversion of AA to acid chloride (AC) using thionyl chloride, followed by the condensation of AC onto PAM and with amine onto PEI to form the graft copolymer. The condensation reaction was fast in formamide solution. The major factors determining the degree of grafting and the chain structure were the AA content of PAM, the molecular weight of PEI and the ratio PEI:PAM. Proposed structures of the graft copolymer chains are discussed. 16 refs. CANADA

Accession no.694435 Item 126 Journal of Applied Polymer Science 69, No.8, 22nd Aug. 1998, p.1669-74 FOURIER TRANSFORM INFRAREDPHOTOACOUSTIC SPECTROSCOPY OF POLY(N-BUTYL METHACRYLATE) ADSORBED FROM SOLUTION ON ALUMINA Pekel N; Guven O Hacettepe,University The adsorption of poly(n-butyl methacrylate) from cyclohexane, benzene and carbon tetrachloride onto alumina was qualitatively and quantitatively analysed using Fourier transform infra-red-photoacoustic spectroscopy. The efficiency of adsorption increased in the order cyclohexane, carbon tetrachloride, benzene, whilst methanol and tetrahydrofuran showed negative adsorption. Poly(n-butyl methacrylate) had a negative temperature coefficient of adsorption. 12 refs. TURKEY

Accession no.693610 Item 127 Journal of Applied Polymer Science 69, No.11, 12th Sept.1998, p.2175-85 IR SPECTROSCOPY AS A QUANTITATIVE AND PREDICTIVE ANALYSIS METHOD OF PHENOL-FORMALDEHYDE RESOL RESINS Holopainen T; Alvila L; Rainio J; Pakkanen T T Joensuu,University; Dynoresin Oy A set of resin samples was characterised by IR and carbon13 NMR spectroscopy. The suitability of IR spectroscopy for the quantitative analysis of resins was evaluated by statistical methods using the NMR reference data as calibration. The values of interesting properties, e.g. the amount of free phenol and the formaldehyde-to-phenol molar ratio, of the resins being similar to the calibration resins were predicted from the IR spectra. The predicted results were compared with those observed by carbon-13 NMR spectroscopy. 15 refs. FINLAND; SCANDINAVIA; WESTERN EUROPE

Accession no.692990

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Item 128 Macromolecular Rapid Communications 19, No.8, Aug.1998, p.413-7 DEVELOPMENT OF A SIMPLE EXPERIMENTAL METHOD TO MEASURE INTERPHASE COMPOSITION PROFILES GENERATED BY DIFFUSION IN POLYMERS. FURTHER RESULTS AND COMPARISON WITH RAMAN SPECTROSCOPY Tomba P; Carella J M; Pastor J M; Fernandez M R INTEMA; Mar del Plata,Universidad Nacional; Valladolid,Universidad Composition profiles generated by interdiffusion in the concentrated regime between polyphenylene oxidepolystyrene blend pairs were experimentally determined by two techniques. Three-point bending moment measurements over a convenient temperature range (dynamic mechanical analysis (DMA)) were used to determine interphase composition profiles. Confocal micro-Raman spectroscopy was also used to measure local compositions along a direction which was perpendicular to the original interface. The study included some limiting cases to test accuracy, precision and flexibility of the DMA method. 4 refs. ARGENTINA; EUROPEAN COMMUNITY; EUROPEAN UNION; SPAIN; WESTERN EUROPE

Accession no.692051 Item 129 Journal of Applied Polymer Science 69, No.4, 25th July 1998, p.645-55 MAPPING PHASES OF POLY(VINYL ALCOHOL) AND POLY(VINYL ACETATE) BLENDS BY FTIR MICROSPECTROSCOPY AND OPTICAL FLUORESCENCE MICROSCOPY Dibbern-Brunelli D; Atvars T D Z; Joekes I; Barbosa V C Campinas,Universidade Estadual Fluorescence optical microscopy (FOM) of poly(vinyl alcohol) and poly(vinyl acetate) blends in compositions 9/1, 1/1, and 1/9 (w/w) showed that these blends present phase separation in the solid state. Each domain of the solid samples was identified by FOM as poly(vinyl alcohol)-richer domains by green fluorescence of fluorescein and poly(vinyl acetate)-richer domains by the blue fluorescence of anthracene. The dimensions, shapes, and distributions of these domains were dependent on the initial composition of the polymeric mixtures in solution. Specific interactions between both homopolymers were studied using FTIR microspectroscopy, which allowed the obtaining of spectra for both poly(vinyl alcohol)-richer and poly(vinyl acetate)-richer domains. 24 refs. BRAZIL

Accession no.689629 Item 130 Antec ’98. Volume II. Conference proceedings. Atlanta, Ga., 26th-30th April 1998, p.2085-9. 012

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References and Abstracts

IN-LINE FIBRE-OPTIC NEAR-INFRARED SPECTROSCOPY: FEASIBILITY STUDIES FOR THE SIMULTANEOUS MONITORING OF VINYL ACETATE AND ERUCAMIDE ADDITIVE CONCENTRATIONS IN POLYETHYLENEVINYL ACETATE COPOLYMERS Vedula S; Hansen M G; Deshpande B J Tennessee,University (SPE) Feasibility studies for the simultaneous monitoring of vinyl acetate (VA) and erucamide additive concentrations in EVA copolymers are undertaken using near-infrared (NIR) spectroscopy. Two groups of samples, each group containing different erucamide concentrations for a fixed VA concentration, are used. NIR spectra of flowing molten polymers are obtained in-line using a flow cell attached to an extruder. The first derivatives of the NIR spectra in the region 1900-2000 nm show overlapping peaks of VA and erucamide. These peaks are deconvoluted using multivariate analysis methods. 7 refs. USA

Accession no.687493 Item 131 Antec ’98. Volume II. Conference proceedings. Atlanta, Ga., 26th-30th April 1998, p.2223-7. 012 NEW APPROACH TO THE CHARACTERISATION OF MOLECULAR ORIENTATION IN UNIAXIALLY AND BIAXIALLY STRETCHED SAMPLES OF PETP Cole K C; Daly H B; Sanschagrin B; Nguyen K T; Ajji A Canada,National Research Council; Montreal,Ecole Polytechnique (SPE) The usual approach used to characterise the molecular orientation in biaxially oriented samples by IR spectroscopy is used to measure spectra with polarisation in all three directions - machine, transverse and normal (or thickness). However, the latter measurement is rather difficult to make experimentally. A new approach to characterising the molecular orientation in both uniaxially and biaxially oriented samples of PETP is employed. It makes use of the ratio of the absorption bands near 1250 and 1725 cm-1, the first of which shows parallel dichroism and the second perpendicular dichroism. An equation is developed that relates this ratio to the molecular orientation with respect to the direction of measurement. Thus it is possible to determine individually the orientation functions with respect to the machine and transverse directions. The validity of functions determined in this way is confirmed by comparison with birefringence results. 9 refs. CANADA

Accession no.687420

© Copyright 2001Rapra Technology Limited

Item 132 Antec ’98. Volume II. Conference proceedings. Atlanta, Ga., 26th-30th April 1998, p.2215-8. 012 PRACTICAL ANALYSIS TECHNIQUES OF POLYMER FILLERS BY FOURIER TRANSFORM INFRARED SPECTROSCOPY (FTIR) Coles B J; Hall C J Hauser Inc. (SPE) The identification of polymers by FTIR is often complicated by the presence of fillers. However for kaolin clay, an FTIR analysis should be able to identify the filler and predict its concentration using a standard curve. The resulting percentage is more reliable than a simple ash, which may change the chemical composition of the filler. 2 refs. USA

Accession no.687418 Item 133 Polymer 38, No.15, 1998, p.3327-33 FTIR STUDY OF GRAFT COPOLYMER COMPATIBILIZERS FOR BLENDS OF FUNCTIONALIZED POLYPROPYLENE AND LIQUID-CRYSTALLINE POLYESTER Sek D; Kaczmarczyk B Polish Academy of Sciences FTIR spectroscopy was used to characterise mixtures of PP functionalised with 6 wt% of acrylic acid (PPAA) and liquid crystalline polyester (PPAA contents of 50% or 70%), graft copolymers of PPAA with the monomers from which the polyester was derived (sebacic acid, 4,4'dihydroxybiphenyl and d-hydroxybenzoic acid, again with PPAA contents of 50% or 70%) and the fractionation products of the graft copolymers. The aim of the investigation was to study the structure of compatibilisers consisting of the graft copolymers and the grafting was followed by measuring changes in the amount of carboxylic and aliphatic-aromatic ester groups. the results were discussed. 3 refs. EASTERN EUROPE; POLAND

Accession no.686650 Item 134 Applied Spectroscopy 52, No.5, May 1998, p.702-12 ANALYSIS AS A FUNCTION OF TEMPERATURE OF THE DYNAMIC LINEAR INFRARED DICHROISM SPECTRA OF ISOTROPIC AND COLD-DRAWN HIGH-DENSITY POLYETHYLENE Lagaron J M; Steeman P A M; Kip B J DSM Research

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A dynamic linear infrared dichroism study was carried out as a function of temperature on isotropic and cold drawn HDPE using a rapid-scan setup. The dynamic in-phase dichroic spectrum and its components (parallel and perpendicular polarised spectra) were analysed. 15 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; NETHERLANDS; WESTERN EUROPE

Accession no.685291 Item 135 Applied Spectroscopy 52, No.5, May 1998, p.692-701 INVESTIGATIONS OF RADICAL POLYMERISATION AND COPOLYMERISATION REACTIONS IN OPTICALLY LEVITATED MICRODROPLETS BY SIMULTANEOUS RAMAN SPECTROSCOPY, MIE SCATTERING, AND RADIATION PRESSURE MEASUREMENTS Musick J; Popp J; Trunk M; Kiefer W Wurzburg,University The combination of optical levitation with Raman spectroscopy, elastic (Mie scattering), and radiation pressure measurements enables in-situ and real-time investigation polymerisation and copolymerisation processes in microdroplets. The time-dependent evolution of the polymerisation and copolymerisation reactions of styrene/unsaturated polyester resin was characterised by observing the educt and product signals in the Raman spectra. The size, the refractive index, and the wavelength dependence of the optically levitated microparticle were determined from the position of the morphologydependent resonances observed in Raman spectra, in elastic light scattering, and in radiation pressure measurements. 36 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.685290 Item 136 Macromolecules 31, No.11, 2nd June 1998, p.3753-5 APPLICATION OF REAL TIME MID-INFRARED FTIR IMAGING TO POLYMERIC SYSTEMS. I. DIFFUSION OF LIQUID CRYSTALS INTO POLYMERS Snively C M; Koenig J L Case Western Reserve University The FTIR imaging method was extended to the real-time acquisition of images from systems varying with time. Emphasis is given to the monitoring of the diffusion of a low molecular weight liquid crystal pentylcyanobiphenyl into a solid polybutyl methacrylate film. 22 refs. USA

Accession no.685003

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Item 137 Journal of Applied Polymer Science 69, No.3, 18th July 1998, p.461-8 APPLICATION OF ATR-FTIR SPECTROSCOPY COMBINED WITH SPUTTER ETCHING FOR DEPTH PROFILING OF A CHEMICAL ADDITIVE WITHIN A PULP FIBER Tatsumi D; Yamauchi T Kyoto,University Attenuated total reflection-Fourier transform infra-red (ATR-FTIR) spectroscopy was used to determine the concentration of a chemical additive (cationic polyacrylamide resin) within a pulp fibre. The depth distribution of the additive was determined by sputter etching the fibre surface. The obtained profile was compared qualitatively with that obtained by the variableangle ATR-FTIR depth profiling method. Most of the additive was located at the surface, with some distributed within the fibre. It is concluded that the method can be used to clarify the distribution of other paper additives within a pulp fibre, and that it can be applied to depth profiling of minor components within a solid material. 21 refs. JAPAN

Accession no.684061 Item 138 Polymer Testing ’96. Conference proceedings. Shawbury, 5th-6th Sept.1996, paper 6. 57 IDENTIFICATION OF ADDITIVES IN RUBBER AND PLASTIC MATERIALS BY COMBINED LIQUID CHROMATOGRAPHY/INFRARED SPECTROSCOPY Sidwell J Rapra Technology Ltd. (Rapra Technology Ltd.; Plastics & Rubber Weekly; European Plastics News) The application of the Lab Connections LC Transform Interface for obtaining IR spectroscopic data on additive components from polymeric systems separated by chromatographic means is discussed. Examinations based on molecular size separation in solution using the techniques of gel permeation chromatography and also normal phase and reverse phase high performance liquid chromatography are described. 2 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.683811 Item 139 153rd ACS Rubber Division Meeting - Spring 1998. Conference preprints. Indianapolis, In., 5th-8th May,1998. Paper 7. 012 APPLICATION OF RAMAN MICROIMAGING IN CHARACTERISATION OF POLYMERS Appel R; Zerda T W

© Copyright 2001 Rapra Technology Limited

References and Abstracts

Texas,Christian University (ACS,Rubber Div.)

Luebbe Co.Ltd.; Osaka,Municipal Technical Research Institute; Kwansei-Gakuin,University

The incorporation of high-resolution optics in a Raman spectrometer allows sampling from areas of less than one micron in diameter. The addition of a confocal microscope improves the axial resolution to a couple of microns. Those developments, along with the introduction of notch filters and holographic transmission gratings, allow the reduction of the acquisition time of Raman spectra from minutes to seconds. The fast data collection combined with the high lateral and vertical resolutions makes possible scanning experiments in which the specimen is advanced in micron size steps. Analysis of the spectra provides information on the spatial composition of the sample. Phase separation in binary mixtures of two polymers, Exxpro and Budene, is studied for different composition of the blends. The average domain sizes are determined. 5 refs.

Near-infrared diffuse reflectance spectra were measured by use of a rotating drawer for pellets of 12 kinds of ethylene-vinyl acetate copolymers with vinyl acetate comonomer varying in the 7-44 wt% range. An attempt was made to predict the melting points of these copolymers. The potential of near-infrared spectroscopy with that of Raman spectroscopy in the discrimination of copolymers and the prediction of their properties was given. 23 refs.

USA

Accession no.683227 Item 140 Polymer 39, No.16, 1998, p.3631-40 XPS AND FTIR STUDIES OF INTERACTIONS IN POLY(CARBOXYLIC ACID)/ POLY(VINYLPYRIDINE) COMPLEXES Xu Zhou; Goh S H; Lee S Y; Tan K L Singapore,National University The nature of the complexes formed by the interactions between polyacrylic acid (PAA) and polymethacrylic acid (PMAA) and with poly(4-vinylpyridine) and poly(2vinylpyridine) in ethanol/water solution was studied using Fourier transform infra-red spectroscopy and x-ray photoelectron spectroscopy. The PMAA complexes involved hydrogen-bonding interactions, whilst there was evidence of ionic interactions in the PAA complexes. This difference in the behaviour between the complexes is attributed to the higher acidity of PAA compared with that of PMAA. 23 refs. SINGAPORE

Accession no.682246 Item 141 Journal of Polymer Science : Polymer Physics Edition 36, No.9, 15th July 1998, p.1529-37 DISCRIMINATION OF ETHYLENE/VINYL ACETATE COPOLYMERS WITH DIFFERENT COMPOSITION AND PREDICTION OF THE CONTENT OF VINYL ACETATE IN THE COPOLYMERS AND THEIR MELTING POINTS BY NEAR-INFRARED SPECTROSCOPY AND CHEMOMETRICS Shimoyama M; Hayano S; Matsukawa K; Inoue H; Ninomiya T; Ozaki Y Hyogo,Prefectural Police Headquarters; Bran &

© Copyright 2001Rapra Technology Limited

JAPAN

Accession no.681676 Item 142 Journal of Applied Polymer Science 68, No.5, 2nd May 1998, p.785-92 INFRARED SPECTROSCOPIC STUDY OF SILICA FILM FORMATION AND DECOMPOSITION OF VINYL SILANE DERIVATIVE BY HEAT TREATMENT. II. ON COPPER SURFACE Kim H; Jang J Seoul,National University The thermooxidative degradation and SiOx film formation of poly(vinyl imidazole-co-vinyl trimethoxysilane) on copper was investigated using Fourier transform infrared reflection and absorption spectroscopy. Thermal degradation of the copolymer was catalysed by copper in the film and at the substrate surface. Copper in the copolymer film contributed to the formation of a coppercontaining SiOx film during thermal degradation. Heat treatment caused defects in the copper-containing film, and copper corrosion proceeded through these defects. In a thickly coated sample, the film cracked because of residual stress, resulting in the formation of copper oxides through the crack. Copper oxides in the film interacted with the SiOx film to form a copper-rich phase in near to film defects and cracks. 33 refs. SOUTH KOREA

Accession no.679543 Item 143 Macromolecules 31, No. 7, 7th April 1998, p.2141-51 SELECTIVELY DEUTERATED LIQUID CRYSTALLINE CYANOAZOBENZENE SIDECHAIN POLYESTERS. III. INVESTIGATIONS OF LASER-INDUCED SEGMENTAL MOBILITY BY FOURIER TRANSFORM INFRARED SPECTROSCOPY Kulinna C; Hvilsted S; Hendann C; Siesler H W; Ramanujam P S Riso National Laboratory; Essen,University The laser-induced anisotropy in thin films of an extensive number of cyanoazobenzene sidechain liquid crystalline

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polytetradecanedioates, -dodecanedioates, and -adipates selectively deuterated at different positions was investigated by FTIR. The analysis of the segmental orientation based on dichroic ratios of characteristic absorption bands shows that, in polyesters with long mainchain spacing (tetradecanedioates and dodecanedioates), not only the light sensitive azo chromophore, but also the main-chain methylene segment and to a small extent the flexible spacer are preferentially oriented perpendicular to the laser light polarisation. The extent of orientation increases with increasing spacer length. On the other hand, in the shorter adipates only the chromophore and the spacer are likewise oriented. Rapid-scan FTIR analysis performed on-line with the laser irradiation reveals that the alignment of the aliphatic segments arises simultaneously with the chromophore orientation. Temperature dependent IR investigations of the laserinduced orientation shows that the preservation of the photoinduced anisotropy directly relates to the polyester phase behaviour. Relevance to rewritable optical storage is suggested. 41 refs. DENMARK; EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; SCANDINAVIA; WESTERN EUROPE

Accession no.679222 Item 144 Colour Quantification: Adding Value With Instruments. Retec proceedings. Baltimore, MD, 15th-17th Sept.1997, paper 11. 52 MEASURING STABILISERS IN PIGMENTED PLASTICS WITH NEAR-INFRARED SPECTROSCOPY Solera P; Nirsberger M; Castillo N Ciba Specialty Chemicals Corp. (SPE,Color & Appearance Div.) Near-infrared (NIR) spectroscopy has become a commonplace analytical tool in the plastics industry. NIR techniques have made quantification of many organic components in polymer processing easy and quick. The work presented outlines the methodology for using NIR to measure stabiliser levels in colour concentrates and natural polymer formulations. Advantages and limitations are considered as well as particle size and product form. 4 refs. USA

Accession no.672730 Item 145 Polymer Degradation and Stability 58, Nos.1-2, 1997, p.15-31 FTIR EMISSION SPECTROSCOPY APPLIED TO POLYMER DEGRADATION Celina M; Ottesen D K; Gillen K T; Clough R L Sandia National Laboratories The thermal degradation of some common polymers is investigated using IR emission spectroscopy. The potential of the technique to contribute to polymer degradation

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studies is demonstrated by measuring the spectroscopic changes that occur during thermal degradation, oxidation or decomposition of polymers under air at temperatures ranging from 150 to 25 deg.C. Polymer types studied include EPDM and nitrile rubbers (commercial materials containing some inorganic fillers), PMMA, PAN, PA, PVC and PS. The resulting qualitative changes in the polymers are easily detected, and are correlated with the current knowledge on the degradation mechanisms of these materials. These include simple carbonyl formation and related oxidative reactions, weight loss and volatilisation, as well as formation of conjugation and specific polymer reactions. Some fundamental aspects and limitations of the technique are discussed to demonstrate the intrinsic difficulties of attempting to determine precise emittances and ultimately quantitative spectroscopic information. FTIR emission appears to be promising for studying in situ polymer degradation. 33 refs. USA

Accession no.668861 Item 146 Polymer 39, No.3, 1998, p.573-82 FTIR. SPECTROSCOPY ON ELECTRON IRRADIATED POLYTETRAFLUOROETHYLENE Fischer D; Lappan U; Hopfe I; Eichhorn K-J; Lunkwitz K Dresden,Institute of Polymer Research The effect of radiation dose and the hydrolysis conditions on the chemical structure of electron irradiated PTFE was studied by different methods of FTIR spectroscopy. Irradiation produced acid fluoride (COF) groups and under ambient conditions, these hydrolysed with atmospheric humidity to form free and associated carboxylic acid (COOH) groups. The concentration of these groups was different in the near-surface regions and in the bulk phase. The formation of carboxylic groups in different states of association depended on the hydrolysis conditions. The results were discussed in detail. 9 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.665954 Item 147 Applied Spectroscopy 51, No.12, Dec.1997, p.1784-90 DEPTH PROFILING STUDY OF EFFECT OF ANNEALING TEMPERATURE ON POLYMER/ POLYMER INTERFACES IN LAMINATES USING CONFOCAL RAMAN MICROSPECTROSCOPY Hajatdoost S; Olsthoorn M; Yarwood J Sheffield,Hallam University; Utrecht,University The effect of annealing temperature on molecular interactions at the interface of polymer laminates was

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References and Abstracts

reported. Depth profiling was carried out using confocal Raman microspectroscopy to study polyacrylonitrile/ polyvinyl alcohol and polyacrylonitrile/polyacrylic acid laminates. The laminates were annealed at 65, 75 and 90C. It was demonstrated that the degree of hydrogen bonding interaction between the nitrile and alcohol groups near the interfacial region changes between laminates annealed at different temperatures. For comparison, Raman mapping of a polyacrylonitrile-polyvinyl alcohol blend was used to study the interactions between the polymers in this (disordered) system. 29 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; NETHERLANDS; UK; WESTERN EUROPE

Accession no.665697 Item 148 Applied Spectroscopy 51, No.11, Nov.1997, p.1736-40 GENERALISED TWO-DIMENSIONAL FOURIER TRANSFORM INFRARED PHOTOACOUSTIC SPECTRAL DEPTH-PROFILING ANALYSIS Jiang E Y; McCarthy W J; Drapcho D L; Crocombe R A Bio-Rad Laboratories Inc. A new application of generalised two-dimensional correlation spectroscopy in photoacoustic depth-profiling analysis. Both rapid-scan and step-scan photoacoustic spectroscopy (obtained by using the software-based digital signal processing technique) of multilayer samples were used to calculate generalised two-dimensional correlation maps. Advantages of this unambiguous analysis method in enhancing spectral as well as depth resolutions, over conventional two-dimensional correlation and other spectral depth-profiling methods, were discussed. 31 refs. USA

Accession no.665694 Item 149 Polymer Degradation and Stability 57, No.3, 1997, p.339-48 CLEARCOAT ANALYSIS IN ISOLATED AND MULTI-LAYER PAINT SYSTEMS BY CONFOCAL RAMAN MICROSCOPY Dupuie J L; Weber W H; Scholl D J; Gerlock J L Ford Motor Co. Confocal Raman spectroscopy was used to characterise the chemical composition of clearcoats in three paint systems: weathered and unweathered samples of isolated acrylic/melamine and acrylic/urethane clearcoats, polyester urethane clearcoats in weathered and unweathered samples of a complete paint system on plastic, and UV light cured acrylic clearcoats on polycarbonate substrates. 11 refs. USA

Accession no.664076

© Copyright 2001Rapra Technology Limited

Item 150 Journal of Applied Polymer Science 66, No.13, 26th Dec.1997, p.2465-73 MEASURING WATER DIFFUSION IN POLYMER FILMS ON THE SUBSTRATE BY INTERNAL REFLECTION FOURIER TRANSFORM INFRARED SPECTROSCOPY Linossier I; Gaillard F; Romand M; Feller J F Lyon,Universite; Sud Bretagne,Universite A method is presented based on multiple internal reflection-FTIR to measure the diffusion coefficients of liquid in polymer, e.g. PMMA or PS, films applied to a substrate. The experimental method here described was designed primarily to measure in-situ liquid water mass uptake and diffusion based on sorption kinetics, but it can also be suitable for vapours, or for other liquids. 24 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; WESTERN EUROPE

Accession no.664045 Item 151 Polymer Science Series B 39, Nos.9-10, Sept.-Oct.1997, p.358-64 IR SPECTROSCOPIC STUDY OF RADICAL POLYMERISATION KINETICS Kurmaz S V; Roshchupkin V P Russian Academy of Sciences An IR spectroscopic technique for the study of kinetics of radical copolymerisation of acryl and vinyl monomers was developed. The technique is based on monitoring the conversion curves and determining copolymerisation rates in the course of the process separately for each monomer by measuring variations in the intensity of IR absorption bands of reacting vinylidene groups. A comparative study of the copolymerisation of model monomer pairs using monofunctional and polyfunctional compounds provided data on the role of structural-physical transformations, involved in the formation of crosslinked polymers, on the copolymerisation kinetics and on the non-uniformity of distribution of crosslinks in the copolymers formed. 17 refs. RUSSIA

Accession no.662893 Item 152 Pigment & Resin Technology 26, No.6, 1997, p.387-8 POLYMER ANALYSIS USING NEAR INFRARED SPECTROSCOPY Bran & Luebbe Ltd. The use of infrared spectroscopy for polymer analysis is discussed, with particular reference to developments in equipment from Bran & Luebbe. The company offers four individual instruments, each with its own specific area of application for use at various stages in the manufacture

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of polymeric materials. They are the InfraProver, InfraPrime, InfraAlyzer 600 and InfraAlyzer 200, the latter representing the most recent breakthrough in the development technique, providing laboratories with the ability to analyse solid, powdered, semi-solid and liquid materials with a single instrument. The use of each instrument is discussed, and examples of the use of some by industry are described. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.662760 Item 153 Journal of Vinyl and Additive Technology 3, No.3, Sept.1997, p.200-4 FOURIER TRANSFORM INFRARED MICRO SPECTROSCOPY MAPPING. APPLICATIONS TO THE VINYL SIDING INDUSTRY Garcia D; Black J Elf Atochem NA

presence of oxygen or water. It was proposed that the increase in hardness was due to the formation of the ionomer and the imides. 9 refs. USA

Accession no.659564 Item 155 152nd ACS Rubber Division Meeting, Fall 1997. Conference Preprints. Cleveland, Oh., 21st-24th Oct.1997, Paper 40, pp.10. 012 THERMAL AND SPECTROSCOPIC (VIBRATIONAL AND NUCLEAR MAGNETIC RESONANCE) CHARACTERIZATION OF ETHYLENE-PROPYLENE-DIENE (EPDM) ELASTOMERS Winter J M; Edmondson M S; Parikh D R; Mangold D J; Castille M J DuPont Dow Elastomers LLC (ACS,Rubber Div.)

Applications of FTIR microspectroscopy mapping to the vinyl siding industry were examined. Particular attention was paid to determination, in single mapping experiments, of the compositional changes associated with capstock to substrate transition and to evaluation of the degradation species and level observed during weathering exposure throughout the thickness of the siding panel. 4 refs.

The sequence distribution of EPM and EPDM samples prepared using vanadium/aluminium chloride and metallocene catalysts was studied by carbon-13 NMR and Fourier transform IR spectroscopy. The influence of sequence distribution on thermal properties was also investigated. 13 refs.

USA

USA

Accession no.661984

Accession no.658294

Item 154 152nd ACS Rubber Division Meeting, Fall 1997. Conference Preprints. Cleveland, Oh., 21st-24th Oct.1997, Paper 123, pp.19. 012 HNBR AND LONG-TERM SERVICEABILITY IN MODERN AUTOMOTIVE LUBRICANTS. I. ANALYTICAL STUDY Tripathy B S; Smith K C Federal-Mogul Corp. (ACS,Rubber Div.)

Item 156 Biomaterials 18, No.21, 1997, p.1387-409 IN-VIVO DEGRADATION OF POLYURETHANES: TRANSMISSION-FTIR MICROSCOPIC CHARACTERISATION OF POLYURETHANES SECTIONED BY CRYOMICROTOMY McCarthy S J; Meijs G F; Mitchell N; Gunatillake P A; Heath G; Brandwood A; Schindhelm K CSIRO; New South Wales,University

The mechanism responsible for the hardening of hydrogenated nitrile rubber automotive seal compounds on prolonged exposure to automatic transmission fluids at high temperature was investigated using Fourier transform IR spectroscopy. The increase in hardness was found to result primarily from chemical attack at the acrylonitrile (AN) sites. This chemical attack first resulted in the formation of isocyanide or isonitrile ions. The proposed mechanism involved crosslinking at the AN sites through the formation of isonitrile ions and the subsequent formation of imides. The isonitrile intermediate formed ionic bonds resulting in the formation of an ionomer once the concentration became sufficiently high. Ultimately these ions crosslinked to form imides in the

A combination of cryomicrotomy and FTIR microscopy was used to investigate chemical changes in unstrained sheets of Pellethane 2363-80A, Tecoflex EG80A and Biomer caused by biodegradation (18 month subcutaneous ovine implant). Cryomicrotomy was used to obtain thin sections from the surface into the bulk, parallel to the plane of the surface. FTIR microscopy was then used to obtain infra red absorbance spectra. Comparisons between the IR spectra (by spectral subtraction) from implant surface, implant interior and non-implanted controls were used to detect chemical changes. SEM was used to assess microstructural changes owing to biodegradation. 94 refs.

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AUSTRALIA

Accession no.657629

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References and Abstracts

Item 157 Applied Spectroscopy 51, No.3, March 1997, p.362-8 ONLINE POST CONSUMER PACKAGE IDENTIFICATION BY NIR SPECTROSCOPY COMBINED WITH FUZZY ARTMAP CLASSIFIER IN INDUSTRIAL ENVIRONMENT Feldhoff R; Wienke D; Cammann K; Fuchs H Muenster,Institute of Chemical & Biochemical Sensor Research; Nijmegen,Catholic University; Muenster,University An optical set-up consisting of a high-throughput nearIR (NIR) spectrograph with an InGaAs-array detector and specially designed collection optics is used to record spectra from post consumer packages located on an industrial conveyor belt. NIR spectra of packages of different polymers (PE, PETP, PP, PS and PVC) and of a cardboard/plastic compound are recorded between 900 and 1700 nm with 6.3-ms integration time. The visual distinction between the spectra is demonstrated by aid of principal component analysis (PCA) plots. The spectra are further classified by a Fuzzy ARTMAP neural network. The method is assessed to be suitable for online identification under industrial conditions. 16 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; NETHERLANDS; WESTERN EUROPE

Accession no.656293 Item 158 Applied Spectroscopy 51, No.3, March 1997, p.346-9 AMPLITUDE SPECTRUM APPROACH IN DYNAMIC FT-IR SPECTROSCOPY OF UNIAXIALLY ORIENTED POLYETHYLENE TEREPHTHALATE FILMS. I. DRAW RATIO DEPENDENCE Sonoyama M; Shoda K; Katagiri G; Ishida H Toray Research Center Inc. A method of data manipulation using the dynamic magnitude spectrum and the static absorbance spectrum is applied to uniaxially drawn PETP films with five different draw ratios for the evaluation of the amplitude of dynamic structural changes under a sinusoidal strain at the level of a functional group. This analysis reveals that, in the drawn film, the skeletal structures, such as the C-O bond in the ethylene glycol unit and the phenyl ring, are susceptible to deformation by mechanical stretching, while the dynamic structural changes around the methylene group are small. It was assumed that the backbone of the polymer is responsible for the change of the mechanical properties induced by the drawing of the film. 24 refs. JAPAN

Accession no.656292 Item 159 Macromolecular Rapid Communications

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18, No.10, Oct.1997, p.903-9 SIMPLE METHODS FOR ASSESSING THE CONFORMATIONAL SENSITIVITY OF IR BANDS BY DICHROISM Ou-Yang W-C; Chen H-L Kaohsiung,National Institute of Technology; Taiwan,National Tsing Hua University Two methods for evaluating the conformational sensitivities of IR bands from the measurement of dichroic ratio using PEEK as an example. Both methods were based on the fact that the orientation function calculated by all conformationally insensitive bands should be identical. 11 refs. CHINA

Accession no.656202 Item 160 Synthetic Metals 89, No.2, Aug.1997, p.149-52 1320-NM EXCITED FT-RAMAN SPECTRA OF NA-DOPED TRANS-POLYACETYLENE Jin-Yeol Kim; Ando S; Sakamoto A; Furukawa Y; Tasumi M Tokyo,University The Fourier transform-Raman spectra of transpolyacetylene(t-PA) doped with sodium at various concentrations were observed with the 1320 nm laser line. Doping-induced Raman bands for lightly doped t-PA were observed for the first time. The observed wave numbers of the C:C and C-C stretch bands of lightly doped t-PA were lower than those of the corresponding bands of pristine t-PA, whereas the reverse was the case for heavily doped t-PA. The origins of doping-induced Raman bands are discussed in terms of solitons and polarons. 20 refs. JAPAN

Accession no.656141 Item 161 Polymer 38, No.22, 1997, p.5699-702 EFFECTIVE WIDTH OF INTERFACE IN A STRESSED MODEL POLYMER COMPOSITE MEASURED BY MICRO-FTIR Lourie O; Wagner H D; Levin N Weizmann Institute of Science; Israel,Police HQ Materials Laboratory The effect of mechanical deformation on a UV-cured urethane-acrylate polymer and on a silicon carbide/ urethane-acrylate model composite was studied by microFTIR spectroscopy. This technique was used for the first time to measure the width of the interfacial zone beyond which the fibre has no influence on the matrix. the results were discussed. 14 refs. ISRAEL

Accession no.654334

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Item 162 Macromolecular Symposia Vol.119, July 1997, p.277-82 FTIR AND ATR ANALYSES ON A POLYPROPYLENE (PP) SURFACE AFTER PLASMA TREATMENT IN THE STUDY OF CHITOSAN SURFACE GRAFTING TO IMPROVE PP DYEING BEHAVIOUR Rochery M; Lam T M; Crighton J S GEMTEX-ENSAIT; Leeds,University

Gregoriou V G; Hapanowicz R Polaroid Corp.; Nicolet Instrument Corp. Step-scan photoacoustic data are presented that prove the ability of the technique to successfully isolate the infrared signature on the top layer from the infrared spectrum of the bulk material, proving the sub-micron resolution capability of the method. Results are shown that underline the fact that the most serious problem in photoacoustic spectroscopy is saturation at high absorptivities. 12 refs. USA

The treatment of a PP film surface to improve its dyeing behaviour was studied. A plasma treatment was carried out to try to create oxidising groups on this surface, so that it could be then easier to apply a specific polysaccharide chitosan which is reported to be much more reactive than PP and easy to dye. A study about the various parameters of the plasma instrument was necessary to find the optimal treatment. The possible formed oxidising groups were emphasised by FTIR and ATR analyses. Chitosan was applied after the plasma treatment and the dyeing result which was then observed was quite encouraging in certain conditions. 8 refs.

Accession no.653724

EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; UK; WESTERN EUROPE

Specific interactions in binary blends of ethylene-vinyl acetate copolymer with various low molecular weight terpene-phenol tackifying resins (TPR) were systematically investigated, as a function of the composition of the blend and of the electron acceptor ability of the resin, by using attenuated total reflection FTIR spectroscopy. Molecular acid-base were evidenced between TPR hydroxyl groups and EVA carbonyl groups. Quantitative information on the fraction of acid-base bonded entities, the enthalpy and equilibrium constant of pair formation were obtained. A crystalline transition of the EVA copolymer was observed and discussed in terms of enthalpy and entropy considerations based on FTIR and calorimetric DSC investigations. Fundamental results are then summarised to predict the interfacial reactivity of such polymer blends towards acid or basic substrates. 16 refs.

Accession no.653741 Item 163 Macromolecular Symposia Vol.119, July 1997, p.261-8 ORDERING AND MOBILITY OF FERROELECTRIC LIQUID CRYSTAL DIMER AS STUDIED BY FTIR SPECTROSCOPY WITH 2-D IR CORRELATION ANALYSIS Shilov S V; Skupin H; Kremer F; Wittig T; Zentel R St.Petersburg,Institute of Macromol.Compounds; Leipzig,University; Mainz,University Both a conservative rapid-scan FTIR technique and a novel step-scan FTIR technique with two-dimensional analysis were used to study the orientation and the mobility of a ferroelectric liquid crystal dimer during switching under an electric field. The detailed mutual arrangements of different molecular segments (mesogen, poly(methylene) chain, polysiloxane chain) in a smectic C phase were derived from the static spectra. Temperature and electric field strength dependencies of the mobility of these segments are discussed. 18 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; RUSSIA; WESTERN EUROPE

Accession no.653739 Item 164 Macromolecular Symposia Vol.119, July 1997, p.101-11 APPLICATIONS OF PHOTOACOUSTIC STEPSCAN FTIR SPECTROSCOPY TO POLYMERIC MATERIALS

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Item 165 Macromolecular Symposia Vol.119, July 1997, p.89-100 EVIDENCE OF ELECTRON ACCEPTORELECTRON DONOR INTERACTIONS IN THERMOPLASTIC POLYMER BLENDS BY USING FTIR-ATR SPECTROSCOPY Brogly M; Nardin M; Schultz J Institut de Chimie des Surfaces et Interfaces

EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; WESTERN EUROPE

Accession no.653723 Item 166 Macromolecular Symposia Vol.119, July 1997, p.65-77 POLYMERS, ADDITIVES, SURFACTANTS AND THEIR MIXTURES: COMPUTER-BASED SEARCH WITH SPECIAL FTIR LIBRARIES Hummel D O Cologne,University The efficiency of selected search algorithms with specific FTIR libraries of application-defined chemical systems was assessed. This investigation was done with a PC of 850 MB/33 MHz, Windows 3.1 and the SPECTACLE program of LabControl/Cologne. The libraries contained

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References and Abstracts

standardised FTIR spectra of 3601 defined polymers, 530 industrial polymers and resins, 1969 additives (pigments, stabilisers, plasticisers, etc.), 1190 surfactants and 1614 monomers, pyrolysates and educts. For searches, the data density was reduced to 4/cm. 21 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.653721 Item 167 Macromolecular Symposia Vol.119, July 1997, p.49-63 POTENTIAL OF TWO-DIMENSIONAL NEARINFRARED CORRELATION SPECTROSCOPY IN STUDIES OF PRE-MELTING BEHAVIOUR OF NYLON 12 Ozaki Y; Yongliang Liu; Noda I Kwansei-Gakuin,University; Procter & Gamble Co. This review paper discusses the potential of generalised two-dimensional near-infrared correlation spectroscopy in studies of pre-melting behaviour and hydrogen bonds of nylon 12. A study on dissociation and hydrogen bonds of N-methylacetamide is also reviewed as a model compound study of nylon 12. FTIR spectra were measured over a temperature range of 30-150C where gradual weakening of inter- or intramolecular associative interactions and decrease of local order leading to the eventual fusion of nylon 12 crystals are observed. 24 refs. JAPAN; USA

USA

Accession no.653717 Item 169 Polymer 38, No.21, 1997, p.5455-62 STRUCTURE OF STYRENE-ACRYLONITRILE/ BUTADIENE POLYMER STUDIED BY 2D-IR SPECTROSCOPY Steeman P A M; Meier R J; Simon A; Gast J DSM Research; Bruker Analytische Messtechnik GmbH 2D IR spectroscopy involving mechanical excitation is employed to study the mechanical relaxation phenomena in an ABS sample, revealing detailed information regarding the molecular segments involved in macroscopic mechanical relaxation. From the temperature dependence of the dynamic signals it is corroborated that in the ABS sample the polybutadiene rubber relaxes entirely independently from the SAN matrix, and thus is present as a separate phase in the material. The rapidscan variation developed to perform 2D IR experiments offers a significantly reduced measurement time in comparison with the step-scan mode of operation. In particular, in relation to research in the polymer field, in which case stress relaxation is expected to occur during the 2D IR experiment, this presents a major advantage. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; NETHERLANDS; WESTERN EUROPE

Accession no.653720

Accession no.652565

Item 168 Macromolecular Symposia Vol.119, July 1997, p.1-13 APPLICATIONS OF TWO-DIMENSIONAL CORRELATION SPECTROSCOPY IN DEPTHPROFILING PHOTOACOUSTIC SPECTROSCOPY, NEAR-INFRARED DYNAMIC RHEO-OPTICS, AND SPECTROSCOPIC IMAGING MICROSCOPY Noda I; Story G M; Dowrey A E; Reeder R C; Marcott C Procter & Gamble Co.

Item 170 Applied Spectroscopy 51, No.8, Aug.1997, p.1245-50 STUDY OF IMPULSE POLYMER RHEO-OPTICS BY STEP-SCAN FT-IR TIME-RESOLVED SPECTROSCOPY Wang H; Palmer R A; Manning C J Duke,University; Manning Applied Technology

Some new developments of two-dimensional spectroscopy are discussed. As a specific example, twodimensional correlation analysis of a polymer laminate film using several different spectroscopic techniques is presented. The versatility of this technique was developed using depth-profiling photoacoustic spectroscopy, midand near-IR dynamic rheooptical developments, and spectroscopic imaging microscopy. Spatial and temporal variations of near-IR spectra are effectively analysed by the two-dimensional correlation technique. Step-scanning FTIR spectrometers provide an opportunity to obtain desired spectral information often difficult to obtain by the conventional rapid-scanning technique. 12 refs.

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The applicability of step-scan impulse/response FT-IR spectroscopy to the rheo-optical study of polymer films is demonstrated by spectral measurements with isotactic PP. A novel piezoelectrically driven microrheometer is employed to apply repetitive impulses to a polymer sample while time-domain spectra are recorded by stepscan FT-IR spectroscopy. The traditional advantages of Fourier transform spectroscopy are retained while providing a second multiplex advantage for the characterisation of the time-dependence of the sample response. Reproducible results, consistent with the frequency-domain literature data and having good signalto-noise ratio, are obtained. The spectral changes due to molecular reorientation are found to be essentially as fast as the mechanical stretching, also consistent with frequency-domain results. This is thought to be the first reported step-scan FT-IR time-domain rheo-optical

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measurement. This technique appears to be applicable to a variety of polymer samples. The advantages of timedomain measurements over frequency-domain measurements are briefly discussed. 33 refs. USA

Accession no.652416 Item 171 Applied Spectroscopy 51, No.8, Aug.1997, p.1238-44 PHASE-RESOLVED DEPTH PROFILING OF THIN-LAYERED PLASMA POLYMER FILMS BY STEP-SCAN FOURIER TRANSFORM INFRARED PHOTOACOUSTIC SPECTROSCOPY Jiang E Y; Palmer R A; Barr N E; Morosoff N Duke,University; Missouri-Rolla,University After reviewing the background of step-scan interferometric photoacoustic spectroscopy, a step-scan Fourier transform photoacoustic phase-resolved technique and its applications in depth profiling of micrometer-thick layered plasma polymers are described. In particular, the power of direct use of the photoacoustic phase spectrum in both qualitative and quantitative depth profiling of the layered samples is extensively discussed. The effects of both spatial origin and intensity of a photoacoustic signal on its phase are explicitly analysed for both overlapping and distinctive, non-overlapping bands of thin-layered plasma polymer samples. The phase spectrum technique is shown to be a very effective and efficient method of spectral depth profiling analysis. 29 refs. USA

Accession no.652415 Item 172 Applied Spectroscopy 51, No.8, Aug.1997, p.1083-91 IMPROVEMENTS IN USE OF ATTENUATED TOTAL REFLECTION FOURIER TRANSFORM INFRARED DICHROISM FOR MEASURING SURFACE ORIENTATION IN POLYMERS Everall N J; Bibby A ICI Research & Technology Centre; Graseby-Specac Ltd. Improvements in the use of attenuated total reflection (ATR) Fourier transform infrared (FT-IR) dichroism for measuring surface orientation in polymer films are described for PETP. It is shown that normalising band intensifies relative to a nondichroic band, prior to calculating dichroic ratios, eliminates the need to maintain identical contact areas/ pressures when removing, rotating and reclamping samples to the ATR element, which has been a major historical disadvantage of this technique. The normalisation is vital; it makes the calculated dichroic ratios largely insensitive to variations in sample/prism contact area, and less sensitive to uncertainties in the refractive indices and birefringence

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of the polymer. For PETP, it is shown that the birefringence can be neglected in the analysis, and a single approximate refractive index used. This is a significant benefit since the birefringence varies as a function of orientation and crystallinity. Equations are derived which allow the calculation of all second-order orientation parameters and the averaged squared direction cosines, from the normalised ATR dichroic ratios. It is also shown how a single-reflection diamond ATR unit is an ideal tool for this work, since it allows small, hard, or irregularly shaped samples to be examined without fear of damaging the ATR element. 16 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.652413 Item 173 Macromolecules 30, No.8, 21st April 1997, p.2400-7 RAMAN VIBRATIONAL STUDIES OF SYNDIOTACTIC POLYSTYRENE. II. USE OF THE FUNDAMENTAL VIBRATIONAL MODE AS A QUANTITATIVE MEASURE OF CRYSTALLINITY WITH ISOTROPIC MATERIAL Kellar E J C; Evans A M; Knowles J; Gaiotis C; Andrews E H London,University,Queen Mary & Westfield College Raman spectra were taken with the 514.5 nm line of an argon ion laser. Syndiotactic PS was found to exhibit two distinct vibrational peaks in the Raman spectrum corresponding to the fundamental vibrational mode. These features were assigned to the symmetric phenyl ring breathing mode coupled to the polymer backbone. The presence of long all-trans sequences gives rise to a peak at about 773/cm, whereas less well-defined trans/gauche conformations result in a separate peak at 798/cm. With increasing levels of crystallinity, the integrated intensity of the former feature grows at the expense of the highfrequency feature. The use of a series of annealed isotropic films of glassy syndiotactic PS of increasing crystallinity and molten syndiotactic PS has made it possible to examine the precise relationship between these two features and other neighbouring vibrational peaks. The level of crystallinity within each sample was determined independently using wide-angle X-ray scattering, DSC and IR spectroscopic measurements. Results indicate that the relative area under the all-trans fundamental band can be directly related to the crystalline volume fraction within each sample. It is proposed that this Raman vibrational feature centered around 773/cm can be used as a quantitative measure of crystallinity for syndiotactic PS once the contribution from the all-trans sequences in the melt is subtracted from the spectrum. 44 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.651397

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References and Abstracts

Item 174 Macromolecules 30, No.8, 21st April 1997, p.2391-9 TWO-DIMENSIONAL NEAR-INFRARED (NIR) CORRELATION SPECTROSCOPY STUDY OF PREMELTING BEHAVIOUR OF NYLON 12 Ozaki Y; Liu Y; Noda I Nishinomiya,Kwansei-Gakuin University; Procter & Gamble Co. FT-NIR spectra of Nylon 12 in a cast film was measured over a temperature range of 30-150C. The 2D NIR correlation analysis reveals that there are at least eight bands in the 6800-6100/cm region where the first overtone of an NH stretching mode of Nylon 12 is expected to appear. They may be ascribed to free- and hydrogenbonded NH groups in various environments. The asynchronous 2D NIR correlation spectrum in the above region indicates that the amide groups with a free carbonyl oxygen appears first and then unassociated free amide and amide with free NH follow as the temperature in increased. In the 6000-5500/cm region of the synchronous spectrum, four dominant autopeaks corresponding to the first overtones of the methylene stretching modes are observed at 5840, 5770, 5680, and 5640/cm, and negative cross peaks are found between the 5770/cm band and the rest. This observation, together with the careful inspection of the dynamic NIR spectra, suggests that the band at 5770/cm is due to the contribution of the CH stretching vibration of an ordered or highly associated form of Nylon 12, which decreases with temperature, while other NIR bands correspond to more disordered forms. 33 refs. JAPAN; USA

Accession no.651396 Item 175 Journal of Vinyl and Additive Technology 3, No.2, June 1997, p.126-9 APPLICATIONS OF INFRARED SPECTROSCOPY TO CUSTOMER PROBLEMS IN THE VINYL INDUSTRY Garcia D Elf Atochem North America This paper outlines procedures used in the identification of typical PVC formulations, starting with the resin and proceeding to impact modifier, process aids, lubricants, stabiliser system and fillers. The emphasis is on FTIR microscopy as the most versatile approach requiring small samples and minimal to no sample preparation. Other commonly used FTIR techniques are also outlined. Wet separation protocols, applicability and limitations as related to FTIR analysis are discussed. Typical examples include vinyl siding, packaging and bottle formulations as well as contaminants often encountered in these formulations and raw materials. USA

Accession no.650270

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Item 176 Kunststoffe Plast Europe 87, No.7, July 1997, p.12-3 NIR SPECTROSCOPY FOR THE ANALYSIS OF MIXED MATERIALS Pahl M H; Grosse-Aschhoff M Near infrared spectroscopy can be used to analyse the concentrations of all the components of a PVC mixture. Unlike conventional methods for the analysis of mixtures, this technique is not limited to one “critical” component. NIR, after calibration, can analyse all the components in a single measuring operation. This technique is therefore especially suitable for analysing dry blends comprising several components. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.648051 Item 177 Polymer 38, No.14, 1997, p.3435-40 FTIR. INVESTIGATION OF STRUCTURAL MODIFICATION OF POLYCARBONATE DURING THERMODYNAMICAL TREATMENTS Heymans N Bruxelles,Universite The effects of annealing and ageing on IR absorption spectra of polycarbonate were studied. The effect of annealing was primarily a modification of trans-trans and trans-cis population of the carbonate group, leading to a more stable structure with a lower internal energy. Ageing proceeded mainly by extremely local rearrangements compatible with a densified structure. Ageing was, however, accompanied by a slight change in conformational populations. The results were discussed. 34 refs. BELGIUM; EUROPEAN COMMUNITY; EUROPEAN UNION; WESTERN EUROPE

Accession no.647751 Item 178 Applied Spectroscopy 51, No.6, June 1997, p.856-65 APPLICATION OF A SPECTROSCOPIC INFRARED FOCAL PLANE ARRAY(FPA) SENSOR FOR ON-LINE IDENTIFICATION OF PLASTIC WASTE van den Broek W H A M; Wienke D; Melssen W J; Feldhoff R; Huth-Fehre T; Kantimm T; Buydens L M C Nijmegen,Catholic University; Germany,Institute for Biochemical Sensor Research A spectroscopic near-IR imaging system, using a FPA detector, was developed for remote and on-line measurements on a macroscopic scale. On-line spectroscopic imaging requires high-speed sensors and

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EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; NETHERLANDS; WESTERN EUROPE

intensity ratio was obtained when a good solvent such as dimethyl sulphoxide was used, whereas a lower value was obtained when a poor solvent such as malononitrile was used. A linear relationship between the intensity ratio of the IR bands and the dissolution power of nine different kinds of dipolar organic solvents was found. The IR characteristic bands of stereoregular PAN was dependent on not only configuration, but also conformation through the difference of the molecular cohesion state in the solvent-cast film. The effect of configuration and conformation on the IR results was quantitatively studied as a function of the film preparation conditions. NMR and wide angle X-ray diffraction results are given in addition to IR data. 15 refs.

Accession no.647715

JAPAN

short image processing steps. The use of a FPA detector in combination with fast chemometric software was investigated. As these imaging systems generated so much data, multivariate statistical techniques were required to extract the important information from the multidimensional spectroscopic images. These techniques included principal component analysis and linear discriminant analysis for supervised classification of spectroscopic image data. The identification system was constructed, implemented and tested for a real-world application of plastic identification in municipal solid waste. 31 refs.

Accession no.639300 Item 179 Journal of Polymer Science : Polymer Physics Edition 35, No.9, 15th July 1997, p.1361-72 INFRARED DICHROISM AND POLYMER ORIENTATION IN ATTENUATED TOTAL REFLECTION. THEORETICAL CONSIDERATIONS Belali R; Vigoureux J M; Morvan J Besancon,University The partial axial orientation model usually use for strongly oriented polymers was adjusted to samples of weakly aligned polymers and the parameters describing the orientation configuration were related to the dichroic ratios in four particular molecular chain distributions, i.e. randomly, totally, partially and elliptically oriented. A new method that led to the determination of these dichroic ratios from ATR spectra was developed. This method was based only on the use of three distinct polarisations of the beam. All the practical difficulties usually encountered in the other methods were thus eliminated. 28 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; WESTERN EUROPE

Accession no.645643 Item 180 Macromolecules 30, No.6, 24th March 1997, p.1782-6 SOLVENT CASTING EFFECT ON THE INFRARED CHARACTERISTIC ABSORPTION BANDS (1230/1250/CM) OF STEREOREGULAR ISOTACTIC POLY(ACRYLONITRILE) FILM Minagawa M; Yoshida W; Kurita S; Takada S; Yoshii F Yamagata,University; Japan,Atomic Energy Research Institute The solvent casting effect on the IR characteristic absorption bands of stereoregular isotactic PAN film was studied in comparison with those of an atactic sample. The ratio of intensities of the title IR characteristic bands of PAN film was strongly dependent on the kind of dipolar aprotic solvent used in the film preparation. A higher

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Item 181 Macromolecular Symposia Vol.114, Feb.1997, p.151-7 LOCAL MICROSTRUCTURE DEPENDENCE OF PVC INTERACTION WITH SOLVENTS. A FTIR VERIFICATION Gomez-Elvira J M; Tiemblo P; Martinez G; Millan J Madrid,Instituto de Ciencia y Tec.de Polim. Interactions between PVC and either cyclohexanone or N-methyl-2-pyrrolidone were studied by FTIR. The occurrence of local configuration based PVC-solvent interactions, specifically, is demonstrated by studying, first, the changes in FTIR frequency of both the solvent carbonyl band and the PVC carbon-chlorine stretching bands with the composition of PVC-solvent mixtures, and, secondly, the FTIR dichroic behaviour of the same bands upon stretching PVC films containing traces of solvent. The results suggest that the interaction is restricted to a definite number of polymer sites although no information as to the exact type of these sites can be drawn. The number of interaction sites is higher for cyclohexanone than for N-methyl-2-pyrrolidone. The latter turns out to be an original path to investigate polymer interactions. 8 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; SPAIN; WESTERN EUROPE

Accession no.639107 Item 182 Polymer 38, No.11, May 1997, p.2753-8 PHASE TRANSITION IN ETHYLENETETRAFLUOROETHYLENE (ETFE) ALTERNATING COPOLYMER. A SPECTROSCOPIC STUDY Radice S; Del Fanti N; Zerbi G Ausimont; Milano,Politecnico IR and Raman spectroscopy were used to investigate the mechanism, at the molecular level, of the phase transition

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References and Abstracts

in ethylene-tetrafluoroethylene alternating copolymer from the orthorhombic to the hexagonal structure. The study indicated that the transition may result from the generation and propagation of conformational collective defects. The results were discussed. 22 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; ITALY; WESTERN EUROPE

Accession no.638549 Item 183 International Journal of Polymer Analysis and Characterization 3, No.2, 1997, p.145-58 CHARACTERIZATION OF POLYETHYLENE TEREPHTHALATE USING NEAR AND FAR FTIR SPECTROSCOPY Lachenal G Universite Claude Bernard The use of near-IR and far-IR spectroscopies for characterisation of PETP films was investigated. After a brief review of previous work, some examples of transmission spectra of annealed PETP, showing complex changes in the absorption bands, are presented. Near-IR spectroscopy was used to follow the crystallinity (or conformation) of thick PETP films without any sample preparation. 40 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; WESTERN EUROPE

Accession no.637788 Item 184 European Polymer Journal 33, No.3, March 1997, p.375-9 QUANTITATIVE IR SPECTROSCOPIC ANALYSIS OF ETHYLENE-ACRYLATE COPOLYMERS Buback M; Busch M; Droege T; Maehling F O; Prellberg C Gottingen,University IR spectroscopy was used for quantitative analysis of the composition of three ethylene-acrylate copolymers, i.e. ethylene-methyl acrylate, ethylene-butyl acrylate and ethylene-2-ethylhexyl acrylate copolymers. Based on a simple model which explicitly considered vibrational band intensities characteristic for CH and for C:O, copolymer composition could be derived from the ratio of C:O and CH integrated absorbances with a precision of + or -3 mol %. It was not necessary to know the optical path length of the copolymer samples which were subjected to IR analysis as pressed films. 15 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.636548 Item 185 Colloid & Polymer Science

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275, No.4, April 1997, p.323-32 FOURIER TRANSFORM INFRARED STUDY OF POLY(2-HYDROXYETHYL METHACRYLATE)(PHEMA) Perova T S; Vij J K; Xu H Dublin,University The FTIR spectra in the wave number range 450-4500/ cm of PHEMA were studied as functions of water content in the range 38-2.6 wt % and temps. in the range 300373K. The results showed changes in the intensities of the stretching frequencies of the carbonyl band, H-O-H bending vibration and O-H stretching vibration with a change in water content and temp. The results confirmed two types of water in the hydrogel polymer system, tightly bound water and loosely bound water. At low concentrations, water was mainly hydrogen-bonded to the polymer and was described as tightly-bound water. At water concentrations greater than 18 wt % , however, part of the water existed in a different form and behaved as loosely bound water. For concentrations over 30%, there was some evidence that excess water behaved more loosely bound somewhat like bulk water. IR spectroscopic results supplemented those obtained by means of NMR by Smyth et al. and by dielectric spectroscopy. The authors’ results also suggested that some of the water continued to be hydrogen bonded to the polymer until at least a temp. of 373K when the bulk water should have evaporated. FTIR was found to yield greater site-specific insight into the local behaviour of water in hydrated PHEMA. 25 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; IRELAND; WESTERN EUROPE

Accession no.636483 Item 186 Journal of Polymer Science : Polymer Physics Edition 35, No.7, May 1997, p.1055-66 EVALUATION BY FOURIER TRANSFORM INFRARED SPECTROSCOPY OF THE DIFFERENT CRYSTALLINE FORMS IN SYNDIOTACTIC POLYSTYRENE SAMPLES Musto P; Tavone S; Guerra G; De Rosa C Italy,National Research Council; Salerno,University; Napoli,Universita Federico II FTIR spectra of syndiotactic PS semi-crystalline samples were examined by using the spectral subtraction approach. It was shown that FTIR analysis provided a direct method for the evaluation of the amount of alpha and beta form crystalline phases, although both contain chains in the same conformation (trans-planar). 50 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; ITALY; WESTERN EUROPE

Accession no.635541 Item 187 Polymer

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38, No.9, 1997, p.2077-91 RHEO-PHOTOACOUSTIC FTIR STUDIES OF THERMAL HISTORY-STRAIN DEPENDENCE IN POLY(VINYLIDENE FLUORIDE) Ludwig B W; Urban M W North Dakota State University The effect of thermal history on the morphology of PVDF was studied and rheophotoacoustic FTIR spectroscopy was used to measure changes in PVDF network permeability as a function of elongation. The rate at which PVDF was cooled from the melt and the morphological changes caused by annealing had a greater influence on the response of the network to deformations than did molecular weight. Before deformation, the crystalline phase and individual crystal size seemed to have the most effect on permeability but after stresses were applied, the number of tie molecules and their resistance to being pulled from their anchoring crystals dominated the permeability of the network. Annealing PVDF within 20C of its melting point of 170C increased the yield stress and Young’s modulus. Similar effects occurred on reducing the cooling rate. 15 refs. USA

Accession no.634449 Item 188 Polymer 38, No.9, 1997, p.2067-75 STUDY OF THE CONFORMATIONS OF POLY(EPSILON-CAPROLACTAM) AND POLY(EPSILON-CAPROLACTAM)POLYBUTADIENE BLOCK COPOLYMERS BY FTIR SPECTROSCOPY WITH PHOTOACOUSTIC DETECTION AND BY MICRO-RAMAN CONFOCAL SPECTROSCOPY Schmidt P; Fernandez M R; Pastor J M; Roda J Czech Republic,Academy of Sciences; Valladolid,Universidad; Czech Institute of Chemical Technology FTIR spectroscopy with photoacoustic detection and micro-Raman confocal spectroscopy were used to study the conformations of poly(epsilon caprolactam) and poly(epsilon-caprolactam)-polybutadiene block copolymers. In the block copolymers prepared by anionic polymerisation, the fraction of the planar conformation of poly(epsilon-caprolactam) chains decreased with increasing polybutadiene content. In the surface layers formed by rapid saw cutting and in the islands formed by microtome cutting, the content of the planar conformation was lowered. This was substantially increased by water treatment, especially at elevated temperatures. 15 refs. CZECH REPUBLIC; EUROPEAN COMMUNITY; EUROPEAN UNION; SPAIN; WESTERN EUROPE

Accession no.634448 Item 189 Revista de Plasticos Modernos

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71, No.475, Jan.1996, p.42-8 Spanish DETECTION OF DEGRADATIVE MICROSTRUCTURAL CHANGES IN PROPYLENE-ETHYLENE COPOLYMER COMPONENTS BY FT-IR SPECTROPHOTOMETRY Pages P; Carrasco F; Romeu J Cataluna,Universidad Politecnica; Girona,Universidad Fourier transform IR spectrophotometry was used to study the microstructure of propylene-ethylene copolymer samples taken from seats which had degraded during storage or aged during outdoor exposure in an Olympic stadium in Barcelona over a period of 2.5 years. Similar microstructural changes were observed for both types of sample, but these changes were more intense in samples taken from seats which had been subjected to the action of UV irradiation during outdoor exposure. The changes observed included increases in aldehyde and ketone groups and decreases in unsaturation, peroxide, methyl and methylene groups and isotacticity. The results indicated that the main processes taking place were photooxidation and chain scission. 7 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; SPAIN; WESTERN EUROPE

Accession no.632273 Item 190 Journal of Materials Science Letters 16, No.6, 15th March 1997, p.445-7 INFRARED SPECTROSCOPIC STUDIES OF THE INTERACTION BETWEEN NATURAL RUBBER AND CHLORINATED NATURAL RUBBER Cool J W; Edge S; Packham D E Bath,University The interactions that occur within a simple model consisting of NR and a chlorinated NR were studied using SEM, supported by electron probe microanalysis. The 1:1 wt% mixture of NR and chlorinated NR was not totally miscible when cast from xylene. Heating at 170 C for 30 min resulted in a dramatic change. The morphology of the film appeared to be homogeneous, and there was evidence for some type of accelerated chemical oxidation, possibly in the isoprene units in the NR. 7 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.632154 Item 191 RadTech ’96 North America. Volume 1. Conference proceedings. Nashville, Tn., 28th April-2nd May 1996, p.407-16. 895 ATTENUATED TOTAL REFLECTANCE FTIR MICROSCOPY AS AN ANALYTICAL PROBLEM SOLVING TOOL

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References and Abstracts

Buehner R W UCB Chemicals Corp. (RadTech International) Fourier transform IR microscopy has proved useful in characterising contaminants as small as 50 microns in diameter in resins and cured films as well as characterising cured film surfaces. The keys to the successful use of FTIR microscopy are experience in sample preparation, an understanding of light microscopy, and ingenuity in defining solutions. Examples are given of various problems that have been resolved using the attenuated total reflectance FTIR microscope technique. 4 refs. USA

Accession no.628096

50, No.12, Dec.1996, p.1500-4 RAMAN MAPPING OF THE DENTIN/ADHESIVE INTERFACE Wieliczka D M; Spencer P; Kruger M B Missouri,University The degree of adhesive penetration into dentin was studied by micro-Raman spectroscopic examination of the dentin/ adhesive interface. In contrast to previous studies, the Scotchbond multipurpose dentin adhesive penetrated less than 2 micrometres into the acid-etched and, thus, decalcified dentin. There was strong spectroscopic evidence that, upon acid etching of the dentin surface, which was typically performed immediately before the adhesive was applied, the collagen matrix collapsed upon itself. 21 refs. 3M CO.

Item 192 Journal of the Adhesive and Sealant Council. Volume 1. Fall 1996. Conference proceedings. San Francisco, Ca. 3rd-6th Nov.1996, p.521-33. 6A1 ATTENUATED TOTAL REFLECTION FOURIER TRANSFORM INFRARED SPECTROSCOPY (ATR FTIR): USEFUL TOOL FOR MOLECULAR ANALYSIS OF ADHESIVES, SEALANTS AND COATINGS Ishida H Case Western Reserve University (US,Adhesives & Sealants Council)

USA

Attenuated total reflection (ATR) Fourier transform infrared spectroscopy (FTIR) is a useful molecular characterisation technique for studying the surface region of adhesives, sealants, and coatings. As examples of challenging samples, applications for carbon fibre surfaces and their interaction with an epoxy coating are described. Special intensity enhancement observed on carbon fibre surfaces allows the study of surface species of oxidised carbon fibres. Another and more unique application of ATR spectroscopy is optical depth profiling in which a concentration or structural gradient is probed near the surface of a material, such as an adhesive, sealant or coating. Two techniques have been developed. The first method requires obtaining spectra at multiple angles and the analysis is done at a single frequency. On the other hand, the second method utilises multiple frequencies from only one spectrum. This latter technique allows insitu monitoring of structural or concentration changes as a function of time due to the short data acquisition time. Unlike traditional ATR depth profiling techniques, the newly developed methods do not require a guessed profile, eliminating human errors. High spatial resolution and the quantitative nature of the analysis have been demonstrated. 23 refs.

FTIR-ATR spectra of a laminate (PMMA/polyvinyl alcohol) were presented at different base layer thicknesses and different angles of incidence on a zinc selenide substrate. By varying the thickness of the PMMA barrier film, different effective penetration depths in the polyvinyl alcohol were achieved. These results agreed well with the calculated electric fields as a function of distance away from the substrate surface. The work provided the basis for depth profiling measurements to detect interfacial interactions. 18 refs.

USA

Accession no.626545 Item 193 Applied Spectroscopy

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Accession no.622477 Item 194 Journal of Polymer Science : Polymer Physics Edition 32, No.11, Aug.1994, p.1881-7 DEPTH PROFILING OF POLYMER LAMINATES USING FOURIER TRANSFORM (ATR) SPECTROSCOPY: THE BARRIER FILM TECHNIQUE Pereira M R; Yarwood J Durham,University; Sheffield,Hallam University

EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.621617 Item 195 Macromolecules 29, No.23, 4th Nov.1996, p.7460-9 STRUCTURAL INVESTIGATION OF ORTHORHOMBIC-TO-HEXAGONAL PHASE TRANSITION IN POLYETHYLENE CRYSTAL. EXPERIMENTAL CONFORMATION OF THE CONFORMATIONALLY DISORDERED STRUCTURE BY X-RAY DIFFRACTION AND INFRARED-RAMAN SPECTROSCOPIC MEASUREMENTS Tashiro K; Sasaki S; Kobayashi M Osaka,University Structural changes in the orthorhombic-to-hexagonal phase transition of PE crystal was investigated by

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measuring the DSC, X-ray diffraction, and IR and Raman spectra for the geometrically-constrained ultradrawn samples (gel film of Hizex Million 240M HMWPE and commercial ultrahigh modulus fibre called Dyneema from Toyobo Co. Ltd.) in the course of heating up to the melting temperature. The IR and spectral patterns characteristic of the hexagonal phase were confirmed. In particular, the bands characteristic of the disordered short trans segments (shorter than five methylene units) and the bands of the kink or double gauche linkages were detected definitely. The degree of orientation of the averaged chain axis, as detected from the temperature dependence of the X-ray fibre diagram, was reserved well enough even in the hexagonal phase, while the orientational degree of the methylene units, as detected from the polarised IR spectral measurements, was found to be lowered appreciably. This finding, combined with the observation of the trans and gauche bands, has confirmed experimentally and definitely the existence of the conformationally disordered chains in the hexagonal phase. 31 refs. JAPAN

Accession no.621218 Item 196 Journal of Applied Polymer Science 63, No.1, 3rd Jan.1997, p.89-101 REACTION OF POLYACRYLIC ACID AND METAL OXIDES: INFRARED SPECTROSCOPIC KINETIC STUDY AND SOLVENT EFFECT Ho-Shing Wu; Heay-Chain Jone; Jiann-Wen Hwang Yuan Ze,Institute of Technology; Nan Pao Resins Chemical Co.Ltd. IR spectroscopic studies were conducted of the reaction of polyacrylic acid(PAA) and metal oxides (zinc oxide, calcium oxide, cupric oxide, chromium oxide and aluminium oxide). Factors such as the amount of metal oxide, reaction time, solvents, type of metal oxides and temp. were also evaluated to derive the optimum conditions for this reaction. The reactions of chromium oxide and aluminium oxide were far from complete. An extra solvent added to the reaction system could increase the solubility of PAA and metal oxide in the solution to cause complete reaction. The reactivity of the reaction was increased by using a hydrophilic solvent, particularly water and methanol. Furthermore, the reaction rate increased when temp. decreased. The reactivity of the reaction was proportional to the pH value of the metal oxide in the aqueous solution. 16 refs. CHINA; TAIWAN

Accession no.618376 Item 197 Polymer 37, No.26, 1996, p.5807-16 FTIR-RHEOOPTICAL CHARACTERISATION OF THE MOLECULAR ORIENTATION

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BEHAVIOUR OF AMINE CURED EPOXY RESINS DURING CYCLIC DEFORMATION Scherzer T Institut fuer Oberflaechenmodifizierung Rheooptical FTIR spectroscopy was used to study molecular orientation in highly crosslinked epoxy resins based on the diglycidyl ether of bisphenol A and a polyetherdiamine. The rheooptical characterisation of these resins during specific cyclic deformation experiments below the Tg is reported. Epoxy resin films were subject to various successive loading-unloading cycles including elongation, recovery, annealing and stress relaxation to study the reversibility of the orientation during relaxation processes. 33 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.617807 Item 198 Macromolecules 29, No. 22, 21st Oct. 1996, p.7124-9 INVESTIGATION OF POLYMER DIFFUSION IN HYDROGEL LAMINATES USING NEAR-FIELD FTIR SPECTROSCOPY Sahlin J; Peppas N A Purdue University The role of diffusion in gel/gel adhesion was examined by near-field FTIR microscopy. Using a near-field FTIR microscopy technique, compositional maps were obtained with improved spatial resolution and enhanced signal to noise ratio. With this technique, the resolution was enhanced by about a factor of 5. Polymer chain diffusion across a gel/gel interface was a substantial mechanism of adhesion. Diffusion of poly(ethylene glycol) free chains across poly(acrylic acid) gels was investigated. The diffusivity of poly(ethylene glycol) was on the order of 1/100,000,000 to 1/1000,000,000 sq.cm/s for these swollen polymer gels. Poly(ethylene glycol) diffusivity in poly(acrylic acid) gels scaled to the -0.41 power of the molecular weight. This was similar to values reported for polyethylene glycol diffusion in aqueous solution. 20 refs. USA

Accession no.617217 Item 199 Applied Spectroscopy 50, No.11, Nov.1996, p.1360-5 DYNAMIC INFRARED LINEAR DICHROIC SPECTRA OF PRESTRETCHED POLYPROPYLENE Ingemey R A; Strohe G; Veeman W S Duisberg,Gerhard-Mercator University DIRLD (dynamic infrared linear dichroic) spectra of prestretched isotactic polypropylene were recorded. The line shape features in the in-phase spectra are described on the basis of frequency shifts and absorption amplitude

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References and Abstracts

variations during the stretching cycle. Details such as the dichroism of the bands, direction of the shift, and changes in the absorption intensities must be considered to explain signs and shapes of the DIRLD bands. Evidence for chain reorientations under stress was not found. The general principal of frequency shifts and changes in absorption intensities as the origin of DIRLD bands was demonstrated by spectral simulations. 34 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.616827 Item 200 Polymer 37, No. 21, Oct. 1996, p.4705-12 CROSSLINKING COPOLYMERISATION OF EPOXY METHACRYLATES AS STUDIED BY FOURIER TRANSFORM RAMAN SPECTROSCOPY Sandner S; Kammer S; Wartewig S Halle,Martin-Luther-Universitat Bisphenol A bis(2-hydroxypropyl methacrylate) was copolymerised with methyl derivatives of styrene (alphamethylstyrene, 4-methylstyrene and 60/40 3methylstyrene/4-methylstyrene mixture) initiated by ditert-butyl peroxide in the presence of 76 wt% of silica filler (quartz) at 150C-200C. The Raman bands of the carbon-carbon double bond stretching vibrations at 1630 and 1637/cm were found to be suitable for determining the conversion of double bonds of the styrene and methacrylate monomer simultaneously in dependence of the copolymerisation time. The carbonyl bands at 1702 and 1718 /cm were not suitable for assessing conversion of carbon-carbon double bonds. Relevance to polymerisable diluents for use with bisphenol A bis(2hydroxypropyl) methacrylate) in dental applications like restorative composite materials, sealants and adhesives, is suggested. 18 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.616206 Item 201 Macromolecules 29, No. 19, 9th Sept. 1996, p.6256-61 RELAXATION OF SEGMENTAL ORIENTATION AND CHAIN EXTENSION IN POLYCARBONATE STUDIED BY INFRARED DICHROISM AND SHRINKAGE Lundberg L; Stenberg B; Jansson J F Stockholm,Royal Institute of Technology The relaxation of the segmental orientation and the chain extension in polycarbonate (Makrolon 1143 from Bayer AG) were studied by IR dichroism and heat shrinkage after a step strain deformation to a draw ratio of 1.75. This makes it possible to distinguish between local relaxation mechanisms (Rouse) and large-scale relaxation

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mechanisms of the molecular orientation. It was found that the average relaxation time for segmental orientation is shorter and more temperature dependent than the average relaxation time for the chain extension. The segmental orientation relaxes almost totally at 170C (Tg 148C) before the chain extension even starts to relax. 16 refs. SCANDINAVIA; SWEDEN; WESTERN EUROPE

Accession no.616185 Item 202 Journal of Applied Polymer Science 62, No.11, 12th Dec.1996, p.1903-11 SURFACE AND INTERFACIAL FOURIER TRANSFORM INFRARED SPECTROSCOPIC STUDIES OF LATEXES. XVI. QUANTITATIVE ANALYSIS OF SURFACTANT IN MULTILAYERED FILMS Niu B J; Urban M W North Dakota State University Migration and concentration levels of sodium dioctylsulphosuccinate(SDOSS) surfactant molecules in silicone-modified 50%/50% styrene/butyl acrylate latex were detected at the film-substrate and film-air interfaces in mono- and double-layered films. The SDOSS content was shown to be influenced by the presence of trimethoxysilyl propylmethacrylate siloxane. Quantitative polarised ATR FTIR spectroscopy was used to analyse the content of the SDOSS molecules. 22 refs. (Pt.XV, ibid, p.1893-901) USA

Accession no.616095 Item 203 Progress in Organic Coatings 28, No.4, Aug.1996, p.279-83 VIBRATIONAL SPECTROSCOPIC STUDY OF DISTRIBUTION OF SODIUM DODECYL SULPHATE IN LATEX FILMS Amalvy J I; Soria D B CIDEPINT; La Plata,Universidad Nacional The migration of the surfactant sodium dodecyl sulphate to the film-air(F-A) and film-substrate(F-S) interfaces during coalescence of a methyl methacrylate-ethyl acrylate latex functionalised with methacrylic acid was monitored by IR and ATR-FTIR spectroscopic techniques. Both F-A and F-S interfaces showed surfactant enrichment, revealing a nearly parabolic distribution of surfactant throughout the film. 11 refs. ARGENTINA

Accession no.615836 Item 204 Macromolecular Chemistry & Physics 197, No.11, Nov.1996, p.3523-30

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CHARACTERISATION OF THE DIFFERENCES IN THE CRYSTALLINITY FROM SURFACE TO BULK OF COMPRESSION-MOULDED POLYPROPYLENE SHEETS USING ATTENUATED TOTAL REFLECTION FOURIERTRANSFORM IR SPECTROSCOPY Kawamoto N; Mori H; Nitta K H; Yui N; Terano M Japan,Advanced Institute of Science & Technology The crystallinities of compression-moulded PP sheets were investigated by application of FTIR and ATR FTIR analyses. Two internal reflection elements, Ge and KRS5, with an angle of incidence of 45 degrees, were used to obtain the depth profiles of the crystallinity of PP sheets from the surface to the bulk. The crystallinity in the region from the surface to about 0.7 micrometre depth was significantly lower than that in the bulk. PP sheets with higher comonomer content showed the same tendency, which was enhanced with decreasing moulding temp. 15 refs. JAPAN

Accession no.615802 Item 205 Applied Spectroscopy 49, No. 10, Oct.1995, p.1411-30 RAMAN IMAGING OF HETEROGENEOUS POLYMERS: A COMPARISON OF GLOBAL VERSUS POINT ILLUMINATION Markwort L; Kip B; Da Silva E; Roussel B DSM; Dilor SA Two alternative methods of Raman imaging via global illumination and via point illumination in combination with confocal light collection were applied to the study of heterogeneous polymer systems. The spectral and spatial resolving power of the different techniques was estimated experimentally. The influence of the depth resolution on the Raman image of a defined sample structure was demonstrated in a mathematical simulation. Data are given for PE, PS, polyacrylate, and epoxy resins. 23 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; NETHERLANDS; WESTERN EUROPE

Accession no.615631 Item 206 R’95 - Recovery, Recycling, Re-Integration. Volume III: Mechanical Processes, Logistic Networks, Separation Technologies. Conference proceedings. Geneva, 1st-3rd Sept. 1995, p.III.230-5. 8(13) FAST ONLINE IDENTIFICATION OF PLASTIC MATERIALS BY NEAR INFRARED SPECTROSCOPY Eisenreich N; Hrez J; Kull H; Mayer W Fraunhofer-Institut fuer Chemische Technologie Edited by: Barrage A; Edelmann X (EMPA; Swiss Federal Laboratories for Mat.Testing & Res.)

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An economic method for recycling of plastics has to separate the various types of polymeric materials. As physical methods are not sufficient, the identification has to monitor structural or molecular properties of the polymer. In the near infrared spectral range NIR (700 to 2500 nm), molecules absorb light by overtone or combination vibrations of the C-H, O-H, N-H and C-O bands. The reduced absorption in the NIR allows registration of spectra of bulky plastics of practical interest in recycling. Advantages of the NIR spectral range compared to the IR are: NIR-photo detectors, like Ge, InAs, or InGaAs photodiodes with fast response and higher detectivity; and quartz fibre optics with low attenuation. For fast scanning of the wavelength region of 1000 to 2200 nm, two spectrometers are realised based on acousto-optic tunable filters with a scan speed of 1000 nm/ms and applied to identify the plastics in mass consumer products and household wastes. 16 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.615266 Item 207 Journal of Materials Science Letters 15, No.21, 1st Nov.1996, p.1908-11 ANALYSIS OF STRESS CONCENTRATIONS IN MULTI-FIBRE MICROCOMPOSITES BY MEANS OF RAMAN SPECTROSCOPY Van Den Heuvel P W J; Peijs T; Young R J Eindhoven,University of Technology; UMIST; Manchester,University Preliminary results are presented showing that Raman spectroscopy makes it possible to measure stress concentration factors in fibres adjacent to a fibre break. Use is made of a carbon/epoxy resin multi-fibre microcomposite, in which five different carbon fibres are aligned parallel in a planar array at a predefined interfibre spacing in a dumbbell-shaped tensile bar. 16 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; NETHERLANDS; UK; WESTERN EUROPE

Accession no.615176 Item 208 China Synthetic Rubber Industry 19, No.5, 1996, p.314-6 Chinese APPLICATION OF FT-RAMAN SPECTROSCOPY IN RUBBER ANALYSIS Wang G; Xu F Shenyang,Rubber Industry Products Research Institute The application of FT-Raman spectroscopy in the analysis of rubbers and related materials is discussed. Characteristics of FT-Raman spectroscopy were compared with FTIR. 23 refs. CHINA

Accession no.609956

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References and Abstracts

Item 209 Antec ’96. Volume III. Conference proceedings. Indianapolis, 5th-10th May 1996, p.3131-5 FAST ON-LINE IDENTIFICATION OF PLASTICS BY NEAR-INFRARED SPECTROSCOPY FOR USE IN RECYCLING PROCESSES Eisenreich N; Herz J; Kull H; Mayer W; Rhoe T Fraunhofer-Institut fuer Chemische Technologie (SPE) For economic recycling of plastics, various types of polymeric materials have to be separated in a short period of time. The near-infrared spectral range allows the monitoring of structural or molecular properties of the plastic under investigation. The spectrometer system described is based on optical fibres for absorption and reflexion measurements, an acousto-optic tunable filter and a transputer system. It is able to detect 1,000 spectra/ s and to identify 20 pieces/second. 10 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.609107 Item 210 Polymer 37, No.18, 1996, p.4009-24 FOURIER TRANSFORM RAMAN STUDY OF THE STRAIN-INDUCED CRYSTALLISATION AND COLD CRYSTALLISATION OF NATURAL RUBBER Healey A M; Hendra P J; West Y D Southampton,University Two NR samples (cured and uncured) were studied. In all studies, the samples were stretched to 500% elongation. The Fourier-transform Raman spectrum of NR is presented as a function of time of cold soaking at -25C and of strain with respect to laser polarisation. Under both sets of conditions, changes occur in the spectra that can be attributed to crystallisation. Difference spectra showing only those bands due to crystallisation (i.e. spectra of crystalline NR) are presented, which allows the crystallisation process to be discussed with respect to the conditions under which crystallites are formed. A combination of Fourier-transform Raman and Fouriertransform IR depolarisation spectra was used to deduce preliminary assignments for some of the vibrational bands of natural rubber. 40 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.607325 Item 211 Polymer 37, No.15, 1996, p.3227-31 ISOTACTICITY DETERMINATION OF POLYPROPYLENE USING FT-RAMAN SPECTROSCOPY

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Sundell T; Fagerholm H; Crozier H Abo,Akademi University; Borealis Polymers Oy Carbon-13 NMR was used as the reference method to enable comparison of FT-Raman and FTIR spectroscopies as isotacticity determination methods. Calibration curves relating Raman scattering and IR absorption ratios to the carbon-13 NMR results are presented. The repeatability for both FT-Raman and FTIR measurements was comparable to that of carbon-13 NMR analysis and there was good correlation between between carbon-13 NMR and FT-Raman/FTIR results. The reliabilities of the three methods are statistically evaluated and compared. 9 refs. FINLAND; SCANDINAVIA; WESTERN EUROPE

Accession no.606302 Item 212 Composites Science & Technology 56, No.7, 1996, p.749-54 STUDY OF CARBON FIBRE STRAIN IN MODEL COMPOSITES BY RAMAN SPECTROSCOPY Leveque D; Auvray M H Office National d’Etudes & de Recherches Aerosp. The application of strain to the molecular structure of carbon fibre was shown to cause a linear shift of Raman frequencies. The magnitude of this shift increased with increasing organisation of the fibre structure, from -7/ cm/% for the T800HB intermediate modulus fibre to -11/ cm/% for the M40B high modulus fibre. Raman spectroscopy was shown to be a useful tool for identifying the different interfacial load transfer types from strain profile observation in single fibre model composites under tensile loading, i.e. fibre debonding with or without friction, and elastic stress transfer was well described by the Cox model. The interfacial shear stress distribution, the possible friction coefficient and the longitudinal thermal residual strain were derived from the strain profiles. 9 refs. (9th French National Colloquium on Composite Materials, Saint-Etienne, France, Nov.1994) EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; WESTERN EUROPE

Accession no.605822 Item 213 Polymer International 41, No.1, Sept.1996, p.35-41 FTIR-MICROSPECTROSCOPY(FTIR-M) AND DSC STUDIES OF POLYVINYLIDENE FLUORIDE(PVDF) Benedetti E; Catanorchi S; D’Allesio A; Moggi G; Vergamini P; Pracella M; Ciardelli F Pisa,University; CNR PVDF samples, obtained by casting from THF solutions and submitted to various thermal treatments, were examined by FTIR-M and DSC. This type of analysis permitted examination of microdomains of samples of

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different morphological characteristics and an indication of the polymorphism of PVDF to be obtained. In some cases, the simultaneous presence of two or three forms was observed by comparison of FTIR-M and DSC traces. Vibrational spectra of single crystalline forms could be recorded by FTIR-M on phase homogeneous microdomains. 13 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; ITALY; WESTERN EUROPE

Accession no.605759 Item 214 Polymer 37, No.16, 1996, p.3665-73 ANIONIC POLYMERISATION OF STYRENE AND BUTADIENE INITIATED BY NBUTYLLITHIUM IN ETHYLBENZENE: DETERMINATION OF THE PROPAGATION RATE CONSTANTS USING RAMAN SPECTROSCOPY AND GEL PERMEATION CHROMATOGRAPHY Auguste S; Edwards H G M; Johnson A F; Meszena Z G; Nicol P Bradford,University The rate of monomer loss during the n-butyllithiuminitiated anionic polymerisation of styrene in ethylbenzene was measured using Raman spectroscopy. GPC measurements on the reaction products were used as an indirect method of obtaining the concentrations of the propagating species involved in this reaction. The rate of propagation for styrene polymerisation was determined in the temperature range 25-70 C, and for specified liveend concentrations. 34 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.604626 Item 215 Analyst 121, No.8, Aug.1996, p.1069-74 POLYMER ANALYSIS BY COLUMN LIQUID CHROMATOGRAPHY COUPLED SEMI-ONLINE WITH FOURIER TRANSFORM INFRARED SPECTROMETRY Somsen G W; Rozendom E J E; Gooijer C; Velthorst N H; Brinkman U A T Amsterdam,Free University Additives in polymers were identified by solventelimination based coupling of reversed-phase column liquid chromatography(LC) and FTIR spectrometry. A spray-jet interface was used to deposit the effluent from a narrow-bore LC column on a zinc selenide window. The deposited additives were analysed by FTIR transmission microscopy, yielding identification limits in the low-nanogram range. High-quality IR spectra were obtained for components present in PVC and PP samples.

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These spectra allowed the characterisation of the additives by spectral library search and/or spectral interpretation. The usefulness of the spray-jet interface system for the coupling of size exclusion chromatography(SEC) and FTIR spectrometry was examined on the basis of the analysis of a PS standard mixture. Representative IR spectra of the SEC effluent indicated that the SEC-FTIR system could be used for the determination of compositional changes across the polymer MWD. 25 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; NETHERLANDS; WESTERN EUROPE

Accession no.604342 Item 216 Polymer Science Series A 38, No.5, May 1996, p.517-24 RAMAN SPECTROSCOPIC INVESTIGATION OF THE ORIENTATION PROCESS OF LINEAR POLYETHYLENE Russian Academy of Sciences The potential of polarisation Raman spectroscopy in probing the structure of oriented polymers was shown using linear PE as the example. The evolution of the Raman spectra of PE in the course of drawing from the isotropic state to that with the highest attainable orientation was investigated. The mechanism of transition from the lamellar structure to fibrillar one was shown to be independent of the particular method of an isotropic sample preparation. The use of micro Raman attachment made it possible to study the structure in the necking region. The data obtained showed that the change in orientation of the polymer chains along the length of a neck was continuous. 18 refs. RUSSIA

Accession no.601403 Item 217 Applied Spectroscopy 50, No.7, July 1996, p.900-5 IN SITU NEAR-IR CURE MONITORING OF A MODEL EPOXY MATRIX COMPOSITE Cossins S; Connell M; Cross B; Winter R; Kellar J South Dakota,School of Mines & Technology The curing of an epoxy resin adjacent to an embedded silica optical fibre was monitored in situ by evanescent wave spectroscopy. The epoxy resin was partially fluorinated and had a lower refractive index than the silica fibre. The lower refractive index of the epoxy resin allowed the silica optical fibre to be used as a waveguide for the internal reflection of the near-IR light. The epoxy resin curing was determined as a function of time and temp. by analysis of the near-IR spectrum from the epoxy adjacent to the fibre obtained by the interaction of the evanescent wave that occurred at each internal reflection with the low refractive index epoxy resin. The results obtained showed that epoxy ring-opening and

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References and Abstracts

PS and the routes for interchange amongst them are shown diagramatically. 28 refs.

crosslinking reactions could be followed in real time. Treatment of the fibre with a silane coupling agent had no observable effect on the curing reaction of the epoxy resin. 27 refs.

EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

USA

Accession no.597199

Accession no.600870 Item 218 Polymer 37, No.12, 1996, p.2335-43 DYNAMIC TWO-DIMENSIONAL INFRA-RED SPECTROSCOPY OF THE CRYSTALAMORPHOUS INTERPHASE REGION IN LOWDENSITY POLYETHYLENE Singhal A; Fina L J Rutgers,University Dynamic two-dimensional FTIR was used to study the nature of the interphase in LDPE. A two-dimensional correlation analysis on the dynamic spectra indicates that neat LDPE is comprised of three regions, specifically, an ordered crystalline region, a disordered liquid-like region, and a crystal/amorphous interfacial region. The 1468/cm peak in the methylene bending region is assigned to alltrans structures which primarily reside in the interfacial region. A variety of LDPE samples with different additives are used in order to determine how the additives influence the dynamic mechanical properties of each morphological phase. It is found that talc associates with the crystallites, ethylene vinyl acetate is distributed in all three morphological phases of the LDPE, and pyrene is associated only with the non-crystalline regions. 31 refs. USA

Accession no.599665 Item 219 Macromolecules 29, No.10, 6th May 1996, p.3515-20 RAMAN VIBRATIONAL STUDIES OF SYNDIOTACTIC POLYSTYRENE. 1. ASSIGNMENTS IN A CONFORMATIONAL/ CRYSTALLINITY SENSITIVE SPECTRAL REGION Kellar E J C; Galiotis C; Andrews E H Queen Mary & Westfield College A detailed analysis of the Raman spectrum of syndiotactic PS in the region 600-850/cm was undertaken. As syndiotactic PS exhibits considerable polymorphism, spectra of various preparations including melt-crystallised syndiotactic PS, solvent-crystallised syndiotactic PS and quenched glassy materials, were studied. Peaks are assigned to conformational changes and sequences. Comparison with atactic PS is made. Study of the cross section of a compression moulded plaque exhibiting a skin/core structure revealed the continuous way the structure varied with changing crystallinity. The various physical forms of syndiotactic

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Item 220 Synthetic Metals 71, Nos.1-3, 1st April 1995, p.1825-6 FTIR AND NIR-FT-RAMAN STUDY OF POTENTIAL MOLECULAR FERROMAGNETICS - POLY(DIACETYLENES) SUBSTITUTED WITH NITROXYL RADICALS Shchegolikhin A N; Lazareva O L; Ovchinnikov A A; Spector V N Moscow,Institute of Chemical Physics FTIR spectroscopy and near-infrared-FT-Raman spectroscopy were used to study the molecular structural transformations which occurred during thermal treatment of several nitroxyl substituted diacetylene monomers. These spectroscopic techniques were also used to investigate the solid state polymerisation reactions of the nitroxyl-substituted monomers, “classic” diacetylenes and of polydiacetylenes. The results were discussed. 7 refs. RUSSIA

Accession no.596062 Item 221 Journal of Applied Polymer Science 61, No.2, 11th July 1996, p.231-54 MICRO-RAMAN IMAGING OF HETEROGENEOUS POLYMER SYSTEMS: GENERAL APPLICATIONS AND LIMITATIONS Markwort L; Kip B DSM Using micro-Raman imaging three blends consisting of polypropene/polyethene/ethene-propene copolymer, PBTP/polycarbonate/LDPE, and styrene-acrylonitrile copolymer/styrene-maleic anhydride copolymer/ polydimethylphenylene oxide were studied with regard to compositional and morphological heterogeneities. The general structure of PE fibres in an epoxy resin matrix was also studied. 59 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; NETHERLANDS; WESTERN EUROPE

Accession no.595775 Item 222 Applied Spectroscopy 50, No.6, June 1996, p.708-14 EFFECTS OF SAMPLING PARAMETERS ON PRINCIPAL COMPONENTS ANALYSIS(PCA) OF RAMAN LINE IMAGES Hayden C A; Morris M D Michigan,University

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The effects of spectrometer slit width, spatial resolution and number of spectral variables used for PCA analysis of Raman line-images were studied. Depth of penetration and signal-to-noise considerations dominated the proper selection of slit width for the sample used in this study, 10micrometre-diameter PS spheres embedded in an epoxy resin matrix. With the use of different microscope objectives to analyse the same sample region, the higher-magnification objective gave better results, probably due merely to the larger number of spectra processed. Finally, the number of spectral variables could be reduced significantly before degradation of the PCA image had occurred, especially if the variables were carefully chosen. 9 refs. USA

Accession no.595341 Item 223 Journal of Polymer Science : Polymer Physics Edition 32, No.12, Sept.1994, p.2065-75 FTIR-ATR STUDIES OF DRAWING AND POLING IN POLYMER BILAMINATE FILMS Gang Chi Chen; Ji Su; Fina L J Rutgers,University FTIR-ATR spectroscopy was used to examine the structural variations as a function of depth for drawn and poled single nylon-11 and PVDF films and PVDF/nylon11 bilaminates. Simple one-way drawing in PVDF and nylon-11 produced anisotropy in dipole orientation in the plane transverse to the draw direction. In both single and bilaminate films, the average direction of the amide plane in nylon-11 and the CF2 dipoles in PVDF residues resided in the plane of the film, perpendicular to the subsequent poling field direction as a result of one-way drawing. The transverse plane orientation was depth dependent in nylon-11 in both single and bilaminate films and was attributed to a surface-induced effect. Poling fields of 1.6 MV/cm produced large differences between the surfaces of single films and the bilaminates. The PVDF and nylon11 dipoles important in polarisation appeared to be random at the interior interface of the drawn and poled bilaminates. The results were discussed. 36 refs. USA

Accession no.593532 Item 224 Kautchuk und Gummi Kunststoffe 49, No.5, May 1996, p.354-6 DETERMINATION OF THE SOLUBILITY OF SULPHUR IN ELASTOMERS USING FOURIER TRANSFORM RAMAN SPECTROSCOPY Brimblecombe A; Hendra P J; Wallen P; Chapman A; Jackson K; Loadman J; Van Duin M; Kip B; Hofstraat J W; Schreurs H Southampton,University; Malaysian Rubber Producers’ Research Assn.; DSM Research; Akzo Nobel Central Research BV

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Solubility of elemental sulphur in NR, EPDM, synthetic polyisoprene and deproteinised NR was determined over a period of 5 days. By varying the amount of sulphur added to the elastomers, heating the mixtures and analysing them on cooling in a Fourier Transform Raman instrument, both the immediate and long-term solubility could be assayed. Some of the non-elastomeric components could influence the rate and level of crystallisation. 11 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; NETHERLANDS; UK; WESTERN EUROPE

Accession no.592027 Item 225 Applied Spectroscopy 50, No.5, May 1996, p.558-63 DEPTH PROFILING OF POLY(METHYL METHACRYLATE), POLY(VINYL ALCOHOL) LAMINATES BY CONFOCAL RAMAN MICROSPECTROSCOPY Hajatdoost S; Yarwood J Sheffield,Hallam University It is demonstrated that this technique can be successfully used to study the hydrogen bonding interaction between the ester and alcohol groups near the interfacial region. Various laminates have been studied, and it is demonstrated that the PMMA layers with lower molecular weight show a greater degree of interpretation for a given annealing time. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.590639 Item 226 Journal of Elastomers & Plastics 28, No.2, April 1996, p.140-60 QUANTITATIVE CHARACTERISATION OF POLYMER STRUCTURE BY PHOTOACOUSTIC FOURIER TRANSFORM INFRARED SPECTROSCOPY Parker J R; Waddell W H PPG Industries Inc. The use of photoacoustic FTIR spectroscopy in quantitative analysis of polymers was investigated with reference to determination of vinyl acetate in EVA, acrylonitrile in NBR, ethylene in EPDM, styrene in SBR and vinyl-butadiene in SBR. The results obtained indicated that, despite the theoretical complexities of photoacoustic FTIR spectroscopy, simple quantitative relationships could be found for many of these polymer analyses. 24 refs. USA

Accession no.590610 Item 227 Polymer 37, No.8, 1996, p.1295-303

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References and Abstracts

MONITORING OF REACTIVE PROCESSING BY REMOTE MID INFRA-RED SPECTROSCOPY Mijovic J; Andjelic S Brooklyn,Polytechnic University An alternative approach to remote mid infra-red spectroscopy is presented which utilises gold-coated waveguides instead of fibre optics and which could be used for in-situ real-time process control in practically any environment. The principle objects of the paper are to describe a novel experimental set-up for remote mid infra-red spectroscopy recently assembled in laboratory, and to demonstrate the qualitative and quantitative analysis of the remote mid infra-red data using a multifunctional epoxy/amine formulation as an example. 18 refs. USA

Accession no.588252 Item 228 Acta Polymerica 47, No.4, April 1996, p.170-6 FTIR SPECTROSCOPIC STUDIES ON THE INTERFACIAL REACTIONS OF OXAZOLINEFUNCTIONALISED POLYMERS Schaefer R; Kressler J; Muelhaupt R Freiburg,Universitat The interfacial reaction of immiscible polymeric systems containing oxazoline and carboxylic acid groups, respectively, was studied by FTIR spectroscopy and FTIR microscopy. A poly(butadiene-co-acrylonitrile) rubber, where the nitrile groups are partially converted to oxazoline groups, was thermally annealed in a two-layer specimen with poly(ethylene-co-methacrylic acid). The formation of the esteramide in the interface was measured quantitatively by FTIR difference spectroscopy. 33 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.588230

of the type and amount of termonomer used (in this case only trans 1,4-hexadiene). The sample contains 20% EPDM rubber, 6% polyamide 66 grafted onto EPDM rubber and 74% neat polyamide 66. Some evidence was obtained via IR spectroscopy for the presence of cyclic imide groups, derived from grafted maleic anhydride groupings. No evidence for the use of a coupling agent could be obtained from either the carbon-13 single pulse excitation-magic angle spinning spectra of the interphase enhanced polyamide 66 or from the isolated rubber phase. 45 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; NETHERLANDS; WESTERN EUROPE

Accession no.588229 Item 230 Journal of Applied Polymer Science 60, No.1, 4th April 1996, p.29-35 STUDY OF DIFFUSION AND SORPTION OF BIS(2-CHLOROETHYL)SULPHIDE (SM) AND BIS(2-CHLOROETHYL)ETHER (OM) THROUGH POLYPROPYLENE (PP) AND BIAXIALORIENTED POLYPROPYLENE (BOPP) FILMS BY THE FTIR-ATR SPECTROSCOPIC METHOD Semwal R P; Banerjee S; Chauhan L R; Bhattacharya A; Rao N B S N India,Defence Research & Development Organisation Diffusion of sulphur mustard (SM) and oxygen mustard (OM) in PP and BOPP were measured using FTIR-ATR spectroscopy, which permits the study of the diffusion of liquid through thin polymer films in-situ. The temperature-dependent diffusion coefficients of OM and SM for PP and BOPP were also reported; these were in good agreement with values obtained by the weight gain method. Activation energy of diffusion was determined by both methods. The polymer-penetrant interaction parameter and transport number were calculated for the system PP/OM and BOPP/OM by weight gain method. 24 refs. INDIA

Item 229 Acta Polymerica 47, No.4, April 1996, p.161-9 SPECTROSCOPIC AND QUANTITATIVE CHARACTERISATION OF VARIOUS FRACTIONS OF THE HETEROGENEOUS POLYMER SYSTEM (EPDM-G-MALEIC ANHYDRIDE)-G-POLYAMIDE 66 USING HIGH RESOLUTION CARBON-13 SOLID STATE NMR AND IR TECHNIQUES van der Velden G; Nelissen H; Veermans T DSM Research Bv The structure of EPDM grafted onto polyamide 66 was analysed with high resolution solid state carbon-13 NMR and IR spectroscopy. Details about the EPDM rubber include the amount of rubber incorporated into this blend, the sequence analysis of the EPDM rubber and an estimate

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Accession no.585950 Item 231 Journal of Polymer Science : Polymer Physics Edition 34, No.4, March 1996, p.781-8 ELECTRIC FIELD-INDUCED DIPOLE REORIENTATION IN ORIENTED NYLON 11 BY IN SITU INFRARED SPECTROSCOPY Hsin Her Yu; Fina L J Rutgers,University Dipole reorientation under the influence of an electric field was investigated in oriented nylon 11 films with polarised IR spectroscopy for the amide A (N-H stretching) and amide I (carbonyl stretching) bands. Butterfly-shaped hysteresis loops were obtained from peak intensity versus applied electric field strength. Least-squares Gaussian

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curve fitting of the resolved multiple contributions to the amide I peak show that the components change in either a continuously reducing S-shaped fashion, or in butterflyshaped curves under ac poling fields. Time-dependent studies of the absorption intensities show that both ordered and disordered species switch towards the electric field direction with the application of electric fields higher than the coercive field. Upon field removal, only the disordered species show orientation relaxation away from the field direction. Below the coercive field, neither species responds orientationally to the field. 12 refs. USA

Accession no.585313 Item 232 Euradh ’94. Conference Proceedings. Mulhouse, 12th-15th Sept.1994, p.346-9. 9(12)4 USE OF INTERNAL REFLECTION FTIR SPECTROSCOPY FOR IN-SITU STUDY OF WATER-POLYMER-SUBSTRATE SYSTEMS Linossier I; Gaillard F; Romand M Lyon,Universite Claude Bernard (Societe Francaise du Vide; Institute of Materials; Dechema Institut) Multiple internal reflection FTIR spectroscopy was used for the in-situ determination of water diffusion coefficient through thin PMMA films. The technique was also used to study water uptake at the interface of an adhesive-substrate system and the effect of surface treatment of the substrate on this parameter. These studies were done to assess adhesion loss and durability of polymer-substrate joints. 7 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; WESTERN EUROPE

Accession no.584869 Item 233 Euradh ’94. Conference Proceedings. Mulhouse, 12th-15th Sept.1994, p.85-9. 9(12)4 QUANTITATIVE I.R.R.A.S. ANALYSIS OF ACIDBASE INTERFACIAL INTERACTIONS IN VARIOUS POLYMER/METAL MODEL SYSTEMS: RELEVANCE TO ADHESION Brogly M; Nardin M; Schultz J Centre de Recherches sur Physico-Chemie Surf.Sol. (Societe Francaise du Vide; Institute of Materials; Dechema Institut) Ethylene-vinyl acetate copolymer, terpene-phenol resins, polyethylene oxide, PMMA and some of their blends were solution cast on basic (aluminium oxide) and acidic (hydroxylated glass) substrates. Fourier transform infrared reflection absorption spectroscopy (IRRAS) was used to determine both the nature and the free energy of interfacial adduct formation in the polymer/metal systems. A correlation between IRRAS and adhesive strength may be used to predict both the acid-base work of adhesion and the density of interfacial interacting sites. 14 refs.

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EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; WESTERN EUROPE

Accession no.584819 Item 234 Applied Spectroscopy 50, No.3, March 1996, p.388-93 DENSITY MAPPING IN POLY(ETHYLENE TEREPHTHALATE) USING A FIBRE-COUPLED RAMAN MICROPROBE AND PARTIAL LEASTSQUARES CALIBRATION Everall N; Davis K; Owen H; Pelletier M J; Slater J ICI PLC Partial least-squares analysis was used to calibrate Raman microprobe spectra of PETP films in terms of density, to give insight into changes in crystallinity through the film thickness. The microprobe uses a static multiplexed holographic grating to obtain the entire Raman spectrum in a single shot. 13 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.584714 Item 235 Applied Spectroscopy 50, No.3, March 1996, p.377-81 DYNAMIC STEP-SCAN TWO-DIMENSIONAL FOURIER TRANSFORM INFRARED STUDIES OF UNIAXIALLY DRAWN POLY(ETHYLENE TEREPHTHALATE) FILM Sonoyama M; Shoda K; Katagiri G; Ishida H Toray Research Center Inc. Dynamic two-dimensional IR spectra of uniaxially drawn PETP under a sinusoidal strain were examined. 39 refs. JAPAN

Accession no.584712 Item 236 Cellular Polymers III. Conference proceedings. Coventry, 27th-28th April 1995, paper 3. 6124 USE OF FTIR TO ANALYSE FIRE GASES FROM BURNING POLYURETHANE FOAMS Paul K T Rapra Technology Ltd. (Rapra Technology Ltd.) A large number of different techniques may be used to analyse fire gases including gas chromatography, mass spectrometry, infrared absorption, ion chromatography, chemiluminescence, specific ion electrodes as well as various colourmetric and titrametric techniques. The use of Fourier Transform Infrared Analysis (FTIR) enables a number of the more important gases to be determined continuously. These gases include those of particular importance to polyurethane foam containing fires, e.g. hydrogen cyanide, nitrogen oxides, hydrogen chloride and

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References and Abstracts

hydrogen bromide (from flame retardant additives) as well as carbon monoxide and carbon dioxide which are produced from all fires. The use and limitations of FTIR to analyse fire gases in general is discussed and the fire gases produced by burning polyurethane foams of different types are compared. 4 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.583878 Item 237 Journal of Materials Science 31, No.4, 15th Feb.1996, p.851-60 CHARACTERISATION OF PAN-BASED CARBON FIBRES WITH LASER RAMAN SPECTROSCOPY. I. EFFECT OF PROCESSING VARIABLES ON RAMAN BAND PROFILES Melanitis N; Tetlow P L; Galiotis C Queen Mary & Westfield College Laser Raman spectroscopy was used to characterise the structure and morphology of a series of carbon fibres, to assess the ultimate firing temperature and pregraphitisation drawing during manufacture and to investigate the influence of oxidative treatment upon the integrity of the fibre surface. Ten types of polyacrylonitrile-based carbon fibres of varying modulus, diameter and manufacturing method, were examined. All their spectral features were recorded and analysed in terms of position, bandwidth and band intensity. The observed Raman spectra are discussed in detail and related to alterations in the conditions of manufacture. 49 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.581295 Item 238 Journal of Applied Polymer Science 59, No.9, 28th Feb.1996, p.1417-26 POLYMERISATION KINETICS OF POLYURETHANE AND VINYL ESTER RESIN INTERPENETRATING POLYMER NETWORKS BY USING FOURIER TRANSFORM INFRARED SPECTROSCOPY Lian Hua Fan; Chun Pu Hu; Zhi Ping Zhang; Sheng Kang Ying East China,University of Science & Technology FTIR was applied to the study of polymerisation kinetics of simultaneous interpenetrating polymer networks composed of PU and vinyl ester resin at a temperature range from 60-110C within 0.5h, in which the pendant hydroxyl groups were capped with acetyl groups to minimise the possibility of chemical binding between the two networks. The comparison of vinyl ester resin with or without its pendant hydroxyl groups was also made to examine the intercomponent chemical binding effect. 18 refs. CHINA

Accession no.580925

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Item 239 Macromolecules 29, No.1, 1st Jan.1996, p.239-46 STUDY OF THE MECHANISM AND RATE OF BISMALEIMIDE CURE BY REMOTE IN-SITU REAL TIME FIBRE OPTIC NEAR-INFRARED SPECTROSCOPY Mijovic J; Andjelic S Brooklyn,Polytechnic University The formulation comprised 4,4'-methylenebis(maleimidobenzene) (Matrimid 5295) and 2,2'diallylbisphenol A. In-situ real time study of the progress of the reaction was conducted in the temp. range from 140 to 250C using remote fibre optic near IR spectroscopy. The signal was clean, free from noise, and remarkably reproducible. The principal reaction observed was an alternating copolymerisation involving maleimide and allyl double bonds. Maleimide homopolymerisation was detected only in the initial stages of reaction at temperatures above 200C. The extent of self-condensation (or etherification) of hydroxyl groups on the allyl component, which leads to crosslinking, was observed to vary with reaction temperature, suggesting a path to tailormaking networks with desired morphology and physical/ mechanical properties. 23 refs. USA

Accession no.580381 Item 240 Journal of Polymer Science : Polymer Chemistry Edition 34, No.3, Feb.1996, p.403-11 KINETICS OF CATIONIC PHOTOPOLYMERISATIONS OF DIVINYL ETHERS CHARACTERISED USING IN-SITU RAMAN SPECTROSCOPY Nelson E W; Scranton A B Michigan,State University In-situ Raman spectroscopy experiments were used to determine effective kinetic propagation constants for a series of unsteady-state divinyl ether polymerisations at different isothermal temperatures and light intensities. A series of Raman experiments were performed on cationic photopolymerisations of a divinyl ether initiated with a diaryliodonium salt of hexafluoroantimonate photosensitised by anthracene. Isothermal Raman experiments were performed for a series of reaction temperatures and were used to determine the overall activation energy of the polymerisation reaction. 20 refs. USA

Accession no.578838 Item 241 Composite Interfaces 3, No.3, 1995, p.221-30 EFFECT OF THE MOLECULAR WEIGHT ON

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References and Abstracts

THE SURFACE COMPOSITION OF POLYCARBONATE/POLY(ETHYLENE TEREPHTHALATE) BLENDS BY FOURIER TRANSFORM IR ATTENUATED TOTAL REFLECTANCE SPECTROSCOPY Kugo K; Watanabe E; Kitaura T; Nishino J Konan,University; Gunze Ltd. The surface structure of melt-mixed blends of bisphenol A polycarbonate and PETP was investigated by FTIR attenuated total reflectance spectroscopy. Based on the peak intensity of the aromatic carbonate band for polycarbonate and the aliphatic ester band for PETP by using germanium and KRS-5 ATR crystals, the enrichment of the PETP component in the surface layer of the polycarbonate/PETP blend films was observed. 27 refs. JAPAN

Accession no.577664 Item 242 Journal of Applied Polymer Science 59, No.3, 18th Jan.1996, p.511-20 DYNAMIC FTIR METHOD FOR DETERMINING THE CURING TEMPERATURE RANGES OF AN ACETYLENE-TERMINATED POLYISOIMIDE PREPOLYMER Huang W X; Wunder S L Temple University To determine individual curing temperature ranges of the isoimide-imide isomerisation and crosslinking reactions, a rapid scan dynamic FTIR method was developed in which the two reactions were continuously monitored as the sample was heated at constant rate. Isothermal kinetic data was obtained on FTIR spectrometers using their fast scan capability and GC-IR software. Dynamic FTIR was used with a common kinetics program to monitor the two separate reactions occurring during thermal curing of the acetylene-terminated polyisoimide prepolymer Thermid IP-600 and to determine individual curing temperature ranges of the isoimide-imide isomerisation and crosslinking reactions. Results were compared with dynamic FTIR and the dynamic DSC data obtained for a model compound, IP-6001. 22 refs. USA

Accession no.577637 Item 243 Polymer Bulletin 36, No.1, Jan.1996, p.87-94 RHEO-OPTICAL FOURIER TRANSFORM INFRARED SPECTROSCOPY OF A LIQUID CRYSTALLINE BLOCK COPOLYMER Zebger I; Pospiech D; Boehme F; Eichhorn K J; Siesler HW Essen,University; Dresden,Institute of Polymer Research

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Rheo-optical experiments were conducted in which FTIR polarisation spectroscopy was used to investigate the orientational behaviour of the different constituents of a liquid crystalline block copolymer (copolyester-imide) during uniaxial elongation at different temps. The results exhibited differences in the degree of alignment as well as in the response to the application of the mechanical load. With increasing temp., the level of the applied stress and the induced degree of orientation decreased, while the differences in the orientational behaviour of the mesogen and the flexible spacer were retained. 12 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.576734 Item 244 Macromolecules 28, No.24, 20th Nov.1995, p.8209-15 SULPHONATED POLYSTYRENE IONOMERS NEUTRALISED BY BI- AND MULTIFUNCTIONAL ORGANIC CATIONS. I. AN INFRARED SPECTROSCOPIC STUDY Xiao-Dong Fan; Bazuin C G Quebec,Universite Laval An FTIR investigation of lightly sulphonated PS blended with ten different organic small molecules containing bi-, tri-, and quadrifunctional amine or pyridine groups was undertaken. Proton transfer from the sulphonic acid moieties of the polymer to the nitrogen functions of the small molecules, giving rise to ion pairs and hence ionic crosslinking, was clearly detected. the extent of proton transfer was correlated qualitatively with the relative basicity of the small molecule. A quantitative calculation of the degree of proton transfer was performed, based primarily on the normalised area of the absorption band and shoulder at 900-906/cm. The results range from about 50% proton transfer or less to purine, 2,2'-pyridil,, and Nphenyl-1,4-phenylenediamine to almost complete proton transfer to 1,6-hexanediamine and 1,4-phenylenediamine. Other small molecules were 1,4-phenylenediamine, 4,4'diaminodiphenylsulphone, 3,3-diaminobenzidine, hexamethylene tetramine and terpyridine. 31 refs. CANADA

Accession no.575981 Item 245 Journal of Polymer Science : Polymer Physics Edition 32, No.11, Aug.1994, p.1881-7 DEPTH PROFILING OF POLYMER LAMINATES USING FOURIER TRANSFORM (ATR) SPECTROSCOPY: THE BARRIER FILM TECHNIQUE Pereira M R; Yarwood J Durham,University; Sheffield,Hallam University FTIR-ATR spectra of a laminate (PMMA/polyvinyl alcohol) were presented at different base layer thicknesses

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References and Abstracts

and different angles of incidence on a zinc selenide substrate. By varying the thickness of the PMMA barrier film, different effective penetration depths in the polyvinyl alcohol were achieved. These results agreed well with the calculated electric fields as a function of distance away from the substrate surface. The work provided the basis for depth profiling measurements to detect interfacial interactions. 18 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.573664 Item 246 Antec ’95. Vol.II. Conference Proceedings. Boston, Ma., 7th-11th May 1995, p.2458-62. 012 FTIR MICROSPECTROSCOPIC METHOD FOR CHARACTERISING THE DRYING OF WATERBASED COATINGS Nedea C E; La H M; Campanelli J R Domco Industries Ltd. (SPE) Fourier transform IR microspectroscopy was used to investigate the drying of water-based acrylic polymer coatings on an aluminised substrate. Changes in the absorbance peak heights were monitored as an indication of the remaining water content. The effects on drying of humidity, solids content, coating thickness and the presence of coalescing agents were studied. Coalescing agents were found to increase drying time while aiding film formation. Drying time decreased with increasing solids content and increased with increasing coating thickness. As expected, relative humidity was found to have an important effect on the drying process. 7 refs. CANADA; USA

Accession no.571348 Item 247 Antec ’95. Vol.II. Conference Proceedings. Boston, Ma., 7th-11th May 1995, p.2057-61. 012 QUALITY MONITORING OF RECYCLED PLASTICS WASTE DURING EXTRUSION. I. INLINE NEAR-INFRARED SPECTROSCOPY Reshadat R; Cluett W R; Balke S T; Hall J W Toronto,University; NIRSystems Inc. (SPE) The composition of recycled HDPE/virgin PP blends prepared in a single-screw extruder was monitored inline at three different points by near-infrared spectroscopy. The data were interpreted by simple and multiple linear regression and multivariate methods. 5 refs. CANADA; USA

28, No.22, 23rd Oct.1995, p.7441-6 FOURIER TRANSFORM INFRARED ANALYSIS OF A LINEAR, ANHYDRIDE-CURED EPOXY Tadros R; Timm D C Nebraska,University A linear-chained epoxy resin was formulated from phenyl glycidyl ether and nadic methyl anhydride catalysed by benzyldimethylamine. Intermolecular polymerisations were modelled as a parallel set of propagation reactions. FTIR spectroscopy was used to determine the concentrations of the oxirane, anhydride and ester moieties within the resin as a function of time for two isothermal cures. Data analyses yielded the propagation rate constant as a function of temp. and the concentration of initiator, including contributions from impurities within the resin. Results obtained compared favourably with measurements on fractionated resins, using GPC. Population density distributions are described by Poisson molar distributions for this resin. 25 refs. USA

Accession no.569011 Item 249 Composite Interfaces 3, No.2, 1995, p.101-19 PHYSICOCHEMICAL CHARACTERISATION OF THE FIBRE/MATRIX INTERACTION IN POLYETHYLENE FIBRE/EPOXY MATRIX COMPOSITES. II. CHARACTERISATION OF THE INTERPHASE WITH FTIR MICROSPECTROSCOPY Van Mele B; Verdonck E Brussels,Free University The interphase in PE fibre/epoxy resin matrix composites was studied by FTIR microspectroscopy using a set-up for investigation of the matrix as close to the fibre as a few microns or less. It was shown that moisture present on the fibre surface could influence the polymerisation reaction of the epoxy/anhydride matrix in an irreversible manner. This effect was enhanced for composites from the more hydrophilic PVAl fibre. The fibre/matrix interaction in these thermoplastic fibre composites was also studied by DSC through characterisation of the fibre melting. A decreased ‘DSC interaction parameter’ was found if the composition of the interphase was changed by moisture. For a composite with an epoxy/amine matrix, on the other hand, the DSC interaction parameter was unaffected by moisture from the fibre surface. 22 refs. (Pt.I, ibid, p.83-100) BELGIUM; EUROPEAN COMMUNITY; EUROPEAN UNION; WESTERN EUROPE

Accession no.566704

Accession no.571279 Item 248 Macromolecules

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Item 250 Polymer 36, No.22, 1995, p.4233-8

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RHEO-OPTICAL RAMAN STUDY OF CHAIN DEFORMATION IN UNIAXIALLY STRETCHED BULK POLYETHYLENE Rodriguez-Cabello J C; Merino J C; Jawhari T; Pastor J M Valladolid,Universidad A rheo-optical study was developed to examine the nature of the structural changes, other than chain orientation, that can appear during uniaxial drawing of PE samples. Stretching was performed at room temperature in samples of melt crystallised HDPE and LDPE. Raman spectra were simultaneously collected along with stress and strain data to gain insight into the molecular basis of the properties resulting from the mechanical process. The need for realtime studies was to detect possible transient occurrences that cannot be observed with non-rheo-optical studies. 15 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; SPAIN; WESTERN EUROPE

Accession no.566487 Item 251 Polymer 36, No.17, 1995, p.3385-92 ORIENTATION AND CONFORMATION IN POLY(ETHYLENE TEREPHTHALATE) WITH LOW DRAW RATIOS AS CHARACTERISED BY SPECULAR REFLECTION INFRARED SPECTROSCOPY Guevremont J; Ajji A; Cole K C; Dumoulin M M Canada,National Research Council A quantitative treatment of the specular reflection spectra obtained from the surface of uniaxially drawn PETP samples was performed. A procedure for correcting for the effect of surface irregularities is presented, and an overall orientation function based on the orientation and content of trans-conformers is calculated. The results are correlated with mechanical modulus and crystallinity values. In addition, an unconventional dichroic ratio parameter based on a combination of two major bands is proposed. Results obtained from the Kramers-Kronig analysis and directly from the reflection spectra are discussed. Both are compared with the overall orientation function obtained before. 21 refs. CANADA

Accession no.564806 Item 252 Macromolecular Reports A32, No.7, 1995, p.1077-82 FOURIER TRANSFORM INFRARED SPECTROSCOPIC STUDY OF CONFORMATION OF FREEZE-DRIED ISOTACTIC POLYSTYRENE Dai Q; Liu X; Wang Y Nanjing,University

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Isotactic PS samples were prepared by shock-cooling and subsequent freeze-drying from very dilute solutions in benzene. FTIR studies on these samples indicated that there were conformational differences between them and a normal isotactic PS. Comparison of the IR spectra indicated that spectral changes occurred at the bands near 1261, 1085-1050, 982, 923-906 and 550/cm. The changes in intensities of the crystalline bands showed that the freeze-dried isotactic PS from a very dilute solution exhibited a higher crystallinity than the annealed sample. 11 refs. CHINA

Accession no.564742 Item 253 Journal of Applied Polymer Science 58, No.3, 17th Oct.1995, p.501-14 RHEO-OPTICAL FTIR SPECTROSCOPY OF EPOXY RESINS Scherzer T Halle,Martin-Luther-Universitat The use of rheooptical FTIR spectroscopy to monitor orientation phenomena in highly crosslinked epoxy/amine networks during uniaxial deformation above their Tg was investigated. The resins were prepared from the diglycidyl ether of bisphenol-A and various polyether di- and triamines in order to examine the influence of the structure of the network formed. The molecular orientation was studied in relation to network density and structure. The orientation behaviour was mainly determined by the flexibility of the polyether chain and the homogeneity of the network structure. The epoxy resins were also subjected to successive loading-unloading cycles. The results showed that the orientation of epoxy networks in their rubbery state was completely reversible and that no significant fatigue due to gradual chain rupture occurred until sample failure. 29 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.563380 Item 254 Applied Spectroscopy 49, No.8, Aug.1995, p.1073-8 DYNAMIC TWO-DIMENSIONAL INFRARED SPECTROSCOPY. I. MELT-CRYSTALLISED NYLON 11 Singhal A; Fina L J Rutgers,University Two-dimensional FTIR spectroscopy was used to study the N-H stretching and amide I/amide II region of meltcrystallised nylon 11 thin films on Teflon substrates. The samples were dynamic mechanically oscillated at room temp. at a frequency of 11 Hz. A two-dimensional correlation analysis on the dynamic spectra indicated that the N-H stretching region split into two peaks. Analysis

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References and Abstracts

of two-dimensional crossplots between the N-H stretching region and the amide I/amide II region showed that the prominent peak in the N-H stretching region (about 3300/ cm) was similar in morphological character to the ordered peak of the amide I region. The amide II region resolved into two ordered and one disordered peak. 28 refs. USA

Accession no.563353 Item 255 Polymer Science Series B 37, Nos.5-6, May-June 1995, p.289-92 IR SPECTROSCOPIC STUDY OF THE STRUCTURE OF POLY(VINYL ALCOHOL)POLY(GLYCIDYL METHACRYLATE) GRAFT COPOLYMERS Buslov D K; Korolik E V; Zhbankov R G; Druzhinina T V; Nazar’ina L A; Smolenskaya L M Belarus Academy of Sciences; Moscow,Textile Institute PVAl, poly(glycidyl methacrylate) and their copolymer (obtained by radical graft polymerisation of glycidyl methacrylate onto PVAl fibres) were studied by IR spectroscopy. The spectrum of the graft copolymer was also obtained by mathematical modelling. The spectra regions sensitive to the sites of localisation of the kinetic chains of grafted poly(glycidyl methacrylate) are found within 3600-3100, 1450-1300, 1120-1000 and 700-500/ cm, which correspond to the stretching and bending OH vibrations, stretching carbon-oxygen vibrations, and torsional vibrations of the hydroxyl groups, respectively. It was established that grafted poly(glycidyl methacrylate) molecules are linked to PVAl macromolecules via oxygen atoms of hydroxyl groups. 12 refs. BELARUS; RUSSIA

Accession no.562450 Item 256 Journal of Polymer Science : Polymer Physics Edition 32, No.8, June 1994, p.1493-502 FTIR STUDY OF PVDF IRRADIATED BY MEANS OF SWIFT HEAVY IONS Betz N; Le Moel A; Balanzat E; Ramillon J M; Lamotte J; Gallas J P; Jaskierowicz G DRECAM/SRSIM; CEA-CNRS; ISMRA; Palaiseau,Ecole Polytechnique Fourier transform IR measurements were used to investigate PVDF films which had been irradiated by means of heavy ions (krypton ions) and electrons. Irradiation with krypton ions was carried out in the presence of helium, hydrogen, deuterium and oxygen. Triple bonds were characteristic of krypton ion irradiation. Double bonds (isolated and conjugated) occurred with both types of irradiation but concentrations were higher with the krypton radiation. The results, including the role of oxygen on the chemical modifications, were discussed. 36 refs.

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EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; WESTERN EUROPE

Accession no.562089 Item 257 Journal of Polymer Science : Polymer Physics Edition 32, No.8, June 1994, p.1315-20 FTIR ANALYSIS OF HYDROGEN BONDING IN AMORPHOUS LINEAR AROMATIC POLYURETHANES. II. INFLUENCE OF STYRENE SOLVENT Wang F C; Feve M; Lam T M; Pascault J-P URA CNRS FTIR studies were carried out on a polyurethane gel synthesised by reacting the alpha,omega-hydroxyterminated random copolyadipate of ethanediol and butanediol with 4,4'-diphenylmethane diisocyanate in solution with 30% to 90% (w/w) of styrene. The results of studying N-H vibrations in the stretching and bending regions showed that the N-H groups of the PU could hydrogen bond with C=O groups and other groups in this system. Some of the aromatic rings of the styrene were hydrogen bonded with the N-H groups of the PU. The mole fractions of “free” N-H groups and of N-H groups hydrogen bonded to C=O groups and to the pi orbitals of the aromatic rings were calculated. 9 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; WESTERN EUROPE

Accession no.562071 Item 258 Journal of Polymer Science : Polymer Physics Edition 32, No.7, May 1994, p.1163-74 RAMAN SPECTRAL STUDY OF SOLID AND DISSOLVED POLY(VINYL ALCOHOL) AND ETHYLENE-VINYL ALCOHOL COPOLYMER Cooney T F; Wang L; Sharma S K; Gauldie R W; Montana A J Hawaii,University; Warner-Lambert Co.,Novon Products Group The Raman spectra of ethylene-vinyl alcohol copolymer and poly(vinyl alcohol) were measured and compared. The spectral changes that occurred during the dissolution of poly(vinyl alcohol) in, and the precipitation of films of poly(vinyl alcohol) from, both water and deuterium oxide were studied and the results were discussed. 46 refs. USA

Accession no.562058 Item 259 Journal of Applied Polymer Science 57, No.13, 26th Sept.1995, p.1585-94 QUANTITATIVE ANALYSIS OF FLUOROCARBON POLYMER FINISHES ON WOOL BY FTIR SPECTROSCOPY Church J S; Evans D J

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CSIRO Two contrasting IR spectroscopic techniques, ATR and photoacoustic spectroscopy, were investigated as means for the determination of fluorocarbon polymer finishes on wool fabric. Based on the experimental conditions used, the results of the photoacoustic spectroscopy method are more characteristic of the bulk sample, while the ATR results are more surface specific. Linear calibrations between polymer addition, as determined by total fluorine analysis, and the absorbance of the C-F stretching bands of the normalised spectral data were obtained for a typical commercial fluorocarbon polymer. The quantitative methods developed are used to help access the effects of wear and the subsequent heating of fluorocarbon polymertreated fabric samples. 21 refs. AUSTRALIA

Accession no.561437

Item 262 Macromolecules 28, No.15, 17th July 1995, p.5163-6 REAL-TIME ATTENUATED TOTAL REFLECTANCE-FOURIER TRANSFORM INFRARED SPECTROSCOPY TO MONITOR MULTIACRYLATE POLYMERISATION REACTIONS Dietz J E; Elliott B J; Peppas N A Purdue,University Real-time attenuated total reflectance FTIR spectroscopy was used to follow the conversion during acrylate polymerisations by measuring the presence of functional groups at finite depths from the crystal surface. By varying the film thickness, the reactivity of multiacrylates could be spatially resolved. These results were compared with results from different photocalorimetric studies. 22 refs. USA

Item 260 Polymer Testing 14, No.5, 1995, p.489-94 QUANTITATIVE APPLICATION OF DRIFT SPECTROSCOPY: DETERMINATION OF COMPOSITION OF SPECIAL ACRYLIC FIBRES Pandey G C; Rao K V; Kumar A Indian Petrochemicals Corp.Ltd. A fast, direct and non-destructive method involving no sample preparation was developed for recording a wellresolved and reproducible spectrum of special acrylic fibre (SAF), a precursor for carbon fibre using diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy. A novel method was developed for determining the composition of SAF containing both acrylate and carboxylic acid comonomers. The special feature is that no standard samples (of known composition) are required. 11 refs. INDIA

Accession no.559472 Item 261 Polymer Engineering and Science 35, No.12, June 1995, p.1011-5 IDENTIFICATION OF PLASTIC WASTE USING SPECTROSCOPY AND NEURAL NETWORKS Scott D M; Waterland R L Du Pont de Nemours E.I.,& Co.Inc. A new approach is described for the automated sorting of post-consumer plastic waste. It is shown that rapid and reliable identification of polymers can be achieved using a combination of fixed-filter near-IR spectroscopy and neural network data analysis. The effectiveness of the method is demonstrated for sorting PETP, HDPE, and PVC. 11 refs. USA

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Accession no.558238 Item 263 Macromolecules 28, No.11, 22nd May 1995, p.4040-3 REAL-TIME INFRARED CHARACTERISATION OF REACTION DIFFUSION DURING MULTIFUNCTIONAL MONOMER POLYMERISATIONS Anseth K S; Decker C; Bowman C N Colorado,University; Ecole Nationale Superieure de Chimie de Mulhouse Reaction diffusion is defined as radicals moving by propagating through unreacted double bonds and its significance, rather than segmental diffusion, in the termination reaction is pointed out. Diethylene glycol dimethacrylate was polymerised by UV light. Initiation was stopped at 18% conversion of double bonds and the dark reaction was monitored for 50s by real-time IR spectroscopy. The point at which reaction diffusion began to dominate termination could be accurately determined. The reaction diffusion parameter was found to be independent of the length of time the polymerisation was monitored in the dark. The method was found to be particularly useful for analysing high conversion kinetics. Results were obtained also for poly(ethylene glycol 200) dimethacrylate and poly(ethylene glycol 600) dimethacrylate. By selecting these monomers, the range of glassy to rubbery polymer networks was spanned. 19 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; USA; WESTERN EUROPE

Accession no.557329 Item 264 Applied Spectroscopy 49, No.6, June 1995, p.747-53 SIMULTANEOUS DETERMINATION OF

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References and Abstracts

RUBBER ADDITIVES BY FTIR SPECTROPHOTOMETRY WITH MULTIVARIATE CALIBRATION Blanco M; Coello J; Iturriaga H; Maspoch S; Bertran E Barcelona,Universidad Autonoma A new method for the determination of vulcanised rubber additives by FTIR spectrophotometry using partial leastsquares regression (PLSR) for multivariate calibration was developed. The effect of various wavenumber ranges and the use of the absorbance and first-derivative spectral modes on performance were studied by applying the method to three different sample batches containing several additives in different proportions all of which were resolved with satisfactory results. 15 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; SPAIN; WESTERN EUROPE

Accession no.555868 Item 265 Polyurethanes ’94. Conference proceedings. Boston, Ma., 9th-12th Oct.1994, p.381-3. 43C6 MONITORING THE PRODUCTION OF POLYURETHANES WITH NEAR-INFRARED SPECTROSCOPY Hall J W; DeThomas F A NIRSystems Inc. (SPI,Polyurethane Div.) By the use of near-infrared instrumentation designed specifically for the process environment, the isocyanate content of a urethane polymerisation reaction is monitored in real-time. A standard error of prediction of 0.15% is achieved. Real-time chemical process and analysis yields improvement in product consistency and quality while maximising process efficiency. 4 refs. USA

Accession no.555628 Item 266 Polyurethanes ’94. Conference proceedings. Boston, Ma., 9th-12th Oct.1994, p.375-80. 43C6 APPLICATIONS OF RAMAN SCATTERING TO PLASTICS RECYCLING AND PROCESS MONITORING Ben-Amotz D; Laplant F; Jiang Y; Biermann T Edited by: Purdue,University; BASF Corp. (SPI,Polyurethane Div.) The composition of a polymeric material is of interest throughout its useful life. From process stream to product fabrication, and finally to post-consumer recycling, it is desirable to know not only what types of materials are present, but also their relative concentrations. In many cases, Raman spectroscopy can provide a quick, convenient and relatively inexpensive alternative conventional analytical method for performing these types of determinations. 15 refs. USA

Accession no.555627

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Item 267 Polyurethanes ’94. Conference proceedings. Boston, Ma., 9th-12th Oct.1994, p.280-5. 43C6 IMPROVED TECHNIQUE FOR THE DETERMINATION OF ISOCYANURATE AND ISOCYANATE CONVERSION BY PHOTOACOUSTIC FTIR Bhattacharjee D; Engineer R Dow Chemical Co. (SPI,Polyurethane Div.) Conventional rigid polyisocyanurate foams blown with HCFC-141b often suffer from poorer compressive strengths, dimensional stability and inferior inflammability properties when compared to foams blown with CFC-11. An improved isocyanurate conversion test by photoacoustic Fourier Transform Infra Red technique is introduced. The method is not limited to polyisocyanurate foam, as isocyanate conversion is an important parameter to follow in PU foams as well, especially in all carbon dioxide blown foams. The method is found to be quite reproducible and further statistical analysis to ensure the validity of this technique is under way. 8 refs. USA

Accession no.555511 Item 268 Journal of Applied Polymer Science 56, No.12, 20th June 1995, p.1557-60 DETERMINATION OF FILLER CONTENT IN THERMOPLASTIC COMPOSITES BY FTIR ANALYSIS Fuad M Y A; Yaakob I; Rusli O; Ishak Z A M; Omar A K M Malaysia,Standards & Industrial Research Inst.; Sains Malaysia,University White rice husk ash (predominantly silica) was incorporated as a filler (10, 20, 30 and 40% by weight) into PP homopolymer. Absorption peaks at 480, 621 and 790/cm gave good linearity with increasing filler content. 9 refs. MALAYSIA

Accession no.555101 Item 269 Macromolecular Symposia Vol.94, May 1995, p.75-95 DYNAMIC FTIR SPECTROSCOPY OF POLYMER FILMS AND LIQUID CRYSTALS Gregoriou V G; Palmer R A Durham,Duke University The use of continuous-scan and step-scan FTIR spectroscopic techniques to study the dynamics of the response of polymer films and liquid crystals to external perturbations is described. Results are presented for

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HDPE, LDPE and SBR, and for pentylcyanobiphenyl and pentylcyanophenylcyclohexane liquid crystal molecules. 14 refs. USA

Accession no.554082 Item 270 Macromolecular Symposia Vol.94, May 1995, p.33-49 ROLE OF VIBRATIONAL SPECTROSCOPYMICROSCOPY TECHNIQUES IN POLYMER CHARACTERISATION Chalmers J M; Everall N J ICI Details are given of the use of IR and Raman microscopy/ microprobe spectroscopic techniques for the spatiallyresolved identification, study and characterisation of polymers. Chemical and physical property characterisations are discussed. 35 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.554079 Item 271 Applied Spectroscopy 49, No.5, May 1995, p.672-8 REAL-TIME, MID-INFRARED SPECTROSCOPIC IMAGING MICROSCOPY USING INDIUM ANTIMONIDE FOCAL-PLANE ARRAY DETECTION Lewis E N; Levin I W US,National Institutes of Health A new approach to mid-IR spectroscopic imaging microscopy is described in which instrumentation is designed about an InSb multichannel, focal-plane array detector and a variable-bandpass dielectric filter. The system may be configured for either macroscopic or microscopic applications and high-fidelity, chemically specific images may be acquired in real time. With the dielectric filter use