Polymer Processing with Supercritical Fluids (Rapra Review Reports)

Rapra Review Reports

ISSN: 0889-3144

Polymer Processing with Supercritical Fluids

V. Goodship and E.O. Ogur

Volume 15, Number 8, 2004

Expert overviews covering the science and technology of rubber and plastics

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

Source of original article Title

Item 1 Macromolecules

33, No.6, 21st March 2000, p.2171-83 EFFECT OF THERMAL HISTORY ON THE RHEOLOGICAL BEHAVIOR OF THERMOPLASTIC POLYURETHANES Pil Joong Yoon; Chang Dae Han Akron,University The effect of thermal history on the rheological behaviour of ester- and etherbased 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. GOODRICH B.F.

Location

USA

Authors and afÀliation

Abstract

Companies or organisations mentioned

Accession no.771897

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

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

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Conductive Polymers, W.J. Feast

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Medical, Surgical and Pharmaceutical Applications of Polymers, D.F. Williams

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

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

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

Report 37

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Engineering Thermoplastics, I.T. Barrie, Consultant.

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

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Reinforced Reaction Injection Moulding, P.D. Armitage, P.D. Coates and A.F. Johnson

Report 38

Epoxy Resins, K.A. Hodd

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

Report 40

Internal Mixing of Rubber, J.C. Lupton

Report 41

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

Report 42

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

Report 43

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

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

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

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

Report 44

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

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

Report 45

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

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

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

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

Report 47

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

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

Report 18

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

Report 48

Plastics in Building, C.M.A. Johansson

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

Report 20

Pultrusion, L. Hollaway, University of Surrey.

Report 21

Volume 5 Report 49

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

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

Report 50

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

Report 22

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

Report 51

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

Report 23

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

Report 52

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

Report 24

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

Report 53

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

Report 54

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

Report 55

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

Volume 3 Report 25

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

Report 26

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

Report 56

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

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

Report 57

Joining of Plastics, K.W. Allen, City University. Physical Testing of Rubber, R.P. Brown, Rapra Technology Ltd.

Report 27 Report 28

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

Report 58

Report 29

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

Report 59

Polyimides - Materials, Processing and Applications, A.J. Kirby, Du Pont (U.K.) Ltd.

Report 30

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

Report 60

Physical Testing of Thermoplastics, S.W. Hawley, Rapra Technology Ltd.

Report 31

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

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 34

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

Volume 6 Report 61

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

Report 65

Decorating and Coating of Plastics, P.J. Robinson, International Automotive Design.

Report 66

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

Report 67

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.

Volume 7

Separation Performance, T. deV. Naylor, The Smart Chemical Company. Report 90

Rubber Mixing, P.R. Wood.

Report 91

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

Report 92

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

Report 93

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

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.

Report 100

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

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 101

Report 76

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

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

Report 102

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

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

Report 103

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

Report 104

Plastics ProÀle Extrusion, R.J. Kent, Tangram Technology Ltd.

Report 105

Rubber Extrusion Theory and Development, B.G. Crowther.

Report 106

Properties and Applications of Elastomeric PolysulÀdes, T.C.P. Lee, Oxford Brookes University.

Report 77 Report 78

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

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 107

High Performance Polymer Fibres, P.R. Lewis, The Open University.

Report 81

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

Report 108

Chemical Characterisation of Polyurethanes, M.J. Forrest, Rapra Technology Ltd.

Report 82

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

Report 83

Report 84

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

Report 111

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

Report 112

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

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

Volume 8 Report 85

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

Report 113

Report 86

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

Rubber-ModiÀed Thermoplastics, H. Keskkula, University of Texas at Austin.

Report 114

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

Report 87

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

Report 115

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

Report 88

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

Report 116

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

Report 89

Polymer Membranes - Materials, Structures and

Report 117

Rapid Prototyping, Tooling and Manufacturing, R.J.M.

Report 118

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

Volume 13

Report 119

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

Report 145

Multi-Material Injection Moulding, V. Goodship and J.C. Love, The University of Warwick.

Report 120

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

Report 146

In-Mould Decoration of Plastics, J.C. Love and V. Goodship, The University of Warwick.

Report 147

Rubber Product Failure, Roger P. Brown.

Volume 11

Report 148

Plastics Waste – Feedstock Recycling, Chemical Recycling and Incineration, A. Tukker, TNO.

Report 121

Polyamides as Engineering Thermoplastic Materials, I.B. Page, BIP Ltd.

Report 149

Analysis of Plastics, Martin J. Forrest, Rapra Technology Ltd.

Report 122

Flexible Packaging - Adhesives, Coatings and Processes, T.E. Rolando, H.B. Fuller Company.

Report 150

Mould Sticking, Fouling and Cleaning, D.E. Packham, Materials Research Centre, University of Bath.

Report 123

Polymer Blends, L.A. Utracki, National Research Council Canada.

Report 151

Rigid Plastics Packaging - Materials, Processes and Applications, F. Hannay, Nampak Group Research & Development.

Report 124

Sorting of Waste Plastics for Recycling, R.D. Pascoe, University of Exeter.

Report 152

Report 125

Structural Studies of Polymers by Solution NMR, H.N. Cheng, Hercules Incorporated.

Natural and Wood Fibre Reinforcement in Polymers, A.K. Bledzki, V.E. Sperber and O. Faruk, University of Kassel.

Report 153

Report 126

Composites for Automotive Applications, C.D. Rudd, University of Nottingham.

Polymers in Telecommunication Devices, G.H. Cross, University of Durham.

Report 154

Polymers in Building and Construction, S.M. Halliwell, BRE.

Report 127

Polymers in Medical Applications, B.J. Lambert and F.-W. Tang, Guidant Corp., and W.J. Rogers, Consultant.

Report 155

Styrenic Copolymers, Andreas Chrisochoou and Daniel Dufour, Bayer AG.

Report 128

Solid State NMR of Polymers, P.A. Mirau, Lucent Technologies.

Report 156

Life Cycle Assessment and Environmental Impact of Polymeric Products, T.J. O’Neill, Polymeron Consultancy Network.

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 PolyoleÀns, C. Kröhnke and F. Werner, Clariant Huningue SA.

Volume 12 Report 133 Report 134

Volume 14 Report 157

Developments in Colorants for Plastics, Ian N. Christensen.

Report 158

Geosynthetics, David I. Cook.

Report 159

Biopolymers, R.M. Johnson, L.Y. Mwaikambo and N. Tucker, Warwick Manufacturing Group.

Report 160

Emulsion Polymerisation and Applications of Latex, Christopher D. Anderson and Eric S. Daniels, Emulsion Polymers Institute.

Report 161

Advances in Automation for Plastics Injection Moulding, J. Mallon, Yushin Inc.

Emissions from Plastics, C. Henneuse-Boxus and T. Pacary, Certech.

Report 162

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

Analysis of Thermoset Materials, Precursors and Products, Martin J. Forrest, Rapra Technology Ltd.

Report 163

Polymer/Layered Silicate Nanocomposites, Masami Okamoto, Toyota Technological Institute.

Report 164

Cure Monitoring for Composites and Adhesives, David R. Mulligan, NPL.

Report 165

Polymer Enhancement of Technical Textiles, Roy W. Buckley.

Report 135

Polymers in Sport and Leisure, R.P. Brown.

Report 136

Radiation Curing, R.S. Davidson, DavRad Services.

Report 137

Silicone Elastomers, P. Jerschow, Wacker-Chemie GmbH.

Report 138

Health and Safety in the Rubber Industry, N. Chaiear, Khon Kaen University.

Report 166

Developments in Thermoplastic Elastomers, K.E. Kear

Report 139

Rubber Analysis - Polymers, Compounds and Products, M.J. Forrest, Rapra Technology Ltd.

Report 167

PolyoleÀn Foams, N.J. Mills, Metallurgy and Materials, University of Birmingham.

Report 140

Tyre Compounding for Improved Performance, M.S. Evans, Kumho European Technical Centre.

Report 168

Plastic Flame Retardants: Technology and Current Developments, J. Innes and A. Innes, Flame Retardants Associates Inc.

Report 141

Particulate Fillers for Polymers, Professor R.N. Rothon, Rothon Consultants and Manchester Metropolitan University.

Volume 15

Report 142

Blowing Agents for Polyurethane Foams, S.N. Singh, Huntsman Polyurethanes.

Report 169

Engineering and Structural Adhesives, David J. Dunn, FLD Enterprises Inc.

Report 143

Adhesion and Bonding to PolyoleÀns, D.M. Brewis and I. Mathieson, Institute of Surface Science & Technology, Loughborough University.

Report 170

Polymers in Agriculture and Horticulture, Roger P. Brown.

Report 171

PVC Compounds and Processing, Stuart Patrick.

Rubber Curing Systems, R.N. Datta, Flexsys BV.

Report 172

Troubleshooting Injection Moulding, Vanessa Goodship, Warwick Manufacturing Group.

Report 144

Report 173

Regulation of Food Packaging in Europe and the USA, Derek J. Knight and Lesley A. Creighton, Safepharm Laboratories Ltd.

Report 174

Pharmaceutical Applications of Polymers for Drug Delivery, David Jones, Queen's University, Belfast.

Report 175

Tyre Recycling, Valerie L. Shulman, European Tyre Recycling Association (ETRA).

Polymer Processing with Supercritical Fluids

V. Goodship and E.O. Ogur (European Tyre Recycling Association (ETRA))

ISBN 1-85957-494-7

Polymer Processing with Supercritical Fluids

Contents 1

Supercritical Fluids ..................................................................................................................................3 1.1

What is a Supercritical Fluid? ..........................................................................................................3

1.2

Solvent Strength ...............................................................................................................................3

1.3

Advantages of Supercritical Fluids ..................................................................................................5

1.4

1.6

Polymers in Supercritical Carbon Dioxide (scCO2) .........................................................................5 1.4.1 Amorphous and Semi-Crystalline Polymers ........................................................................6 Supercritical Water (SCW) ...............................................................................................................6 1.5.1 Properties: Dielectric Constant ............................................................................................6 1.5.2 Properties: Ion Product ........................................................................................................7 Supercritical Methanol .....................................................................................................................9

1.7

Supercritical Nitrogen ......................................................................................................................9

1.5

2

Polymer Applications of Supercritical Fluids ........................................................................................9 2.1

Extraction and PuriÀcation ...............................................................................................................9

2.2

2.4

The Basic Principles of SCF Extraction of Polymers ....................................................................10 2.2.1 Choosing Solvent(s) for Supercritical Fluid Extraction (SFE) ..........................................11 2.2.2 Applications of SFE ...........................................................................................................11 Use of SCFs in Polymerisation ......................................................................................................11 2.3.1 Introduction ........................................................................................................................11 Impregnation ..................................................................................................................................13

2.5

Supercritical Fluid Dyeing (SFD) .................................................................................................14

2.6

Rapid Expansion of Supercritical Fluid Solutions (RESS Process) ...............................................15

2.7

Supercritical Anti-Solvents Precipitation (SASP) ..........................................................................15

2.3

3

Processing Applications of SCF Technology ........................................................................................16 3.1

Plasticisation of Polymers ..............................................................................................................16

3.2

3.4

Extrusion ........................................................................................................................................17 3.2.1 Microcellular Foams ..........................................................................................................17 3.2.2 MuCell Extrusion Technology ...........................................................................................19 Injection Moulding .........................................................................................................................19 3.3.1 Trexel: The MuCellTM System............................................................................................20 3.3.2 Ergocell ..............................................................................................................................20 3.3.3 Optifoam Process ...............................................................................................................22 3.3.4 Foamold .............................................................................................................................22 3.3.5 Applications and Properties of Microcellular Foams ........................................................23 Microcellular Blow Moulding ........................................................................................................23

3.5

Blending .........................................................................................................................................23

3.3

4

Hardening of Polymers ..........................................................................................................................24

5

Recycling and Recovery .........................................................................................................................24 5.1

Mechanical Recycling ....................................................................................................................24

5.2

Chemical Recycling .......................................................................................................................24

1

Polymer Processing with Supercritical Fluids

6

Conclusions .............................................................................................................................................25

Additional References ....................................................................................................................................26 Subject Index ................................................................................................................................................125 Company Index ............................................................................................................................................135

The views and opinions expressed by authors in Rapra Review Reports do not necessarily reÁect 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.

2

Polymer Processing with Supercritiical Fluids

1 Supercritical Fluids In the polymer industry supercritical Áuids are currently the subjects of intense research and commercial interest. They can be used for a variety of processes, for example as solvents in polymer synthesis, as plasticising agents or for chemical recycling. Supercritical Áuids of materials such as carbon dioxide and water also offer a ‘green’ solution, in that they do not harm the earth’s environment (181). The development and application of supercritical Áuid (SCF) technology has actually been quite slow, however it is unlikely that the pioneering researchers into supercritical Áuid properties in the early 1900s envisioned the wide-ranging impact supercritical materials would have later in the century, with applications in a variety of industries. Interest really began in the 1960s and 1970s with research into extraction techniques. These experiments used mainly supercritical carbon dioxide in their research and concentrated in the food industry for the extraction of Áavours and essential oils from materials such as hops and herbs and for decaffeinating coffee and tea. The decaffeination of coffee is the process most commonly associated with supercritical fluids and was Àrst carried out on a large production scale, in Germany in 1978. Here, the combined properties of the supercritical Áuid carbon dioxide were realised in a cost competitive and environmentally superior process. The major driver for the development of the SCF process was in the elimination of residual solvents in the products, especially methylene chloride, which had previously been used to decaffeinate coffee. Increasing regulatory attention to solvent residues in food products drove this, which is also driving current research in many polymer Àelds today. However there were also other advantages in employing supercritical fluids in these fields. Extraction by supercritical Áuid also gave improved Áavour and aroma characteristics in comparison to standard extraction practices. In the eighties, interest was heightened in the special solvent properties of supercritical fluids. Now, applications such as the RESS process, which will be described in more detail later on in this review, are part of standard industrial practice. In view of their ever growing importance in the polymer industry there is a need to fully comprehend how supercritical Áuids interrelate with polymeric materials in order to fully realise the potential that can be gained

from their use. This review will therefore begin with a quick introduction to supercritical Áuids.

1.1 What is a Supercritical Fluid? A supercritical Áuid (SCF) is a substance (liquid or gas) which is in a state above its critical temperature (Tc) and critical pressure (Pc). At this critical point liquids and gases coexist, and a supercritical Áuid shows unique properties that are different from those of either liquids or gases under standard conditions. The relationship between temperature, pressure and the formation of a supercritical Áuid can be seen in Figure 1. This is a phase diagram for carbon dioxide, a SCF of particular interest to polymer scientists, which will be discussed in more detail later on in this review. An unusually large compressibility means that the density can be manipulated by small changes in pressure. One enormous benefit being that a SCF exhibits a pressure-tuneable dissolving power that is ideally suited for developing processes for extracting, purifying and recrystallising substances and producing new product forms that at present cannot be obtained by conventional processing technologies. A SCF gives unusual properties, for example a viscosity like that of a gas, a density like that of a liquid, and a diffusion coefÀcient that lies between that of gas and liquid. In addition, it has the gaseous property of being able to penetrate porous and Àbrous solids and the liquid property of being able to dissolve materials into their components. It possesses no surface tension hence no capillary forces will appear during extraction. The solvating power of the SCF follows the changes in the density. The beneÀts accrued from using supercritical Áuids (especially water and carbon dioxide) include but are not limited to the following: (i) environmentally benign solvents, (ii) the ability to selectively tune chemical reactions and solvents, (iii) the ability to enhance reaction rates due to their low viscosities and high diffusivities. The parameters of some commonly used supercritical Áuids are summarised in Table 1.

1.2 Solvent Strength At the critical point the density is extremely sensitive to changes in temperature and pressure. Whilst the densities may be similar to those of organic liquids, the solubility can be orders of magnitude higher. Since the solvent strength is directly related to the density, by control or regulation of the pressure, the solvent

3

Polymer Processing with Supercritical Fluids

supercritical Áuid

Figure 1 Phase diagram for carbon dioxide (NB: At the boiling curve: gas and liquid phases co-exist. At the triple point: all three phases co-exist)

Table 1. Guide to physical parameters of commonly used supercritical solvents Compound

Boiling point (ºC) Nitrogen –195.9 Ethylene –10.8 Carbon dioxide –78.5 Ethane –88.7 Nitrous oxide –88.5 Butane –17.8 Propane –42.1 Ammonia –33.5 Acetone 56.0 Methanol 64.6 Ethanol 78.3 Tetrahydrofuran (THF) 65.0 Toluene 110.6 Water 100.0 * 1 bar=15 psi=100 kPa=0.99 atm

Critical temp. (ºC) -147.0 9.2 31.0 32.2 36.4 91.8 96.6 132.5 235.0 239.4 243.0 267.0 318.6 374.1

strength can be manipulated to simulate (and replace) the properties of many organic solvents. For example they can replace solvents such as hexane, methanol, methylene chloride and chloroform. Even the non-polar nature of supercritical (sc) CO2 material can also be overcome by adding a modiÀer in the form of a polar organic co-solvent. Thus SCFs have the potential to replace numerous chemicals in a variety of industries, apart from the polymer industry.

4

Critical pressure (bar)* 34.0 50.4 73.8 48.8 72.5 46.2 42.5 112.8 46.9 81.0 63.8 51.8 41.0 220.5

Critical density (g/cm³) 0.314 0.218 0.464 0.203 0.452 0.232 0.217 0.235 0.277 0.272 0.276 0.321 0.291 0.322

A supercritical Áuid exhibits physical and chemical properties intermediate between those of liquids and gases. Characteristics of a supercritical fluid are: (i) dense gas, (ii) solubilities approaching liquid phase, and (iii) diffusivities approaching gas phase. These Áuids have densities and diffusivities similar to liquids and viscosities comparable to gases as outlined in Table 2.

Polymer Processing with Supercritiical Fluids

Table 2. Fluid densities and diffusivities Mobile Phase Gas SCF Liquid

Density (g/cm³) –10³ 0.2–0.9 0.8–1.0

Mass transfer with supercritical Áuids is usually fast. Their active viscosities are nearer to those found in normal gaseous states. In the zone of the critical point, the diffusion coefÀcient is more than ten times that of a liquid and both the viscosity and diffusivity are dependent on temperature and pressure. Changes in viscosity and diffusivity are more marked in the area of the critical point. Also at high pressures, viscosity and diffusivity are considerably less than that of a liquid. Therefore, the properties of gas-like diffusivity, gaslike viscosity, and liquid-like density combined with pressure-dependent recovery control have provided the drive for applying supercritical Áuid technology to a variety of problems. The ability to improve solubility by using a material in a supercritical state has been known since the 1870s, therefore supercritical Áuid technology is not entirely a new technology. The unique properties of supercritical Áuids were reported slightly over one hundred years ago by the observation that at high pressures, gases such as carbon dioxide and ethylene, dissolved complex organic compounds and that this dissolving power of these Áuids was a strong function of pressure. However, it was not until the second half of the 1900s that the Àrst commercial scale supercritical processing of polymers was utilised to manufacture tonnes of LDPE per year using supercritical ethylene (a.1). As stated in the introduction, for many years, SCFs have been used in food processing industries to extract compounds such as caffeine, and the ability to purge polymer materials of unwanted contaminants is a new application with growing interest in this area of supercritical Áuid technology.

1.3 Advantages of Supercritical Fluids The advantages of using a SCF can therefore be summarised as follows: 1. SCFs have similar solvating powers to liquid organic solvents, but their higher diffusivities, lower viscosity and lower surface tension make them more effective in many cases. 2. Since their density is pressure-tuneable, separation of substances from solvents is easy to achieve.

Viscosity (Poise) 0.5–3.5(E-4) 0.2–1.0(E-3) 0.3–2.4(E-2)

Diffusivity (cm²/s) 0.01–1.0 0.1–3.3(E-4) 0.5–2.0(E-5)

3. The ability to add modiÀers to a SCF, for example to change the polarity, gives them more selective separation power. 4. Little harm is done to the environment in terms of residues from processes using SCF compared to volatile organic compounds (VOCs) and ozone depleting substances (ODSs). 5. SCFs are generally cheap, safe to use and have minimal disposal costs associated with their operation in industrial processes. By far and away the most widely used SCF of interest to polymer scientists is scCO2 which will now be considered in greater detail.

1.4 Polymers in Supercritical Carbon Dioxide (scCO2) Carbon dioxide (CO2) is the most commonly used supercritical Áuid because of its low critical temperature, low toxicity and high purity at a low cost. It is nonÁammable and its use does not contribute to the net global warming effect. In addition, CO2 is the second most abundant and the second least expensive solvent in the planet. Being a gas under ambient conditions favours its easy removal from polymeric products, thus saving costs on other secondary operations such as drying and solvent removal. This material has a relatively low operating pressure and temperature, which makes obtaining supercritical conditions less expensive then many other SCF materials. For example it is supercritical in a range often already experienced by polymers during manufacturing processes such as extrusion or injection moulding. It can also be easily removed by simply reducing the pressure. It can be easily recovered for recycling and can be used to replace harmful or toxic materials such as Freons. It is miscible with a variety of organic solvents, and can also be used to replace some organic solvents. With a few notable exceptions, most polymers with high molecular weights are not soluble in this material, an exception is Áuoropolymers which do dissolve. However, polymers can take up a signiÀcant quantity of the material in

5

Polymer Processing with Supercritical Fluids

a supercritical state. Amorphous polymers behave differently to semi-crystalline materials, this difference will now be discussed further.

(ii) impregnation and extraction of impurities, (iii) membrane conditioning, (iv) production of microparticles, foams, gels and Àbres and (v) polymerisation reactions.

1.4.1 Amorphous and Semi-Crystalline Polymers

Changes in the physical and mechanical properties of polymers are readily observed through the sorption of supercritical carbon dioxide, with the resultant effect of reduction of the glass-transition temperature. The major effects of supercritical carbon dioxide on amorphous polymers are summarised in Figure 2. Table 3 summarises the effects of scCO2 on both amorphous and semi-crystalline polymers.

At near critical conditions amorphous materials absorb CO2 to a greater extent than semi-crystalline polymers and a greater amount of plasticisation is found to occur. This is because CO2 is absorbed only into amorphous regions and not crystalline regions. As the concentration of the fluid increases, sorption and swelling in amorphous polymers (or amorphous regions of semicrystalline materials) can cause a phase transition from glass to liquid. The glass transition temperature (Tg) of the polymer drops signiÀcantly, a property which can be exploited in polymer processing. Quantities in the region of 10-30% by weight can be absorbed by these materials and treatment with just 8-10% can depress a Tg of 80 °C to below room temperature. The amount of absorption is increased by increases in temperature and pressure, however the polarity of the polymer and the structure of the polymer also determine the solubility of any particular polymer being used. Plasticisation of the polymer also causes an increase in crystallinity, which causes an increase in the melting temperature and induces changes in the mechanical properties of the materials. The different response to scCO2 means that amorphous and semi-crystalline polymers may be more suited to some applications than others. Certainly within the scope of this review it is amorphous polymers that are of most interest. There have been numerous attempts to quantify the plasticisation effects of scCO2 on various polymers, e.g., (72, 90, 94, 101, 113). However, it is difÀcult to deÀnitively state exact levels of either Áuid uptake or level of plasticisation effect for any given polymer, given the many different processes, conditions, and types of the same material which have been tested. All these factors make any comparison virtually impossible. Despite this however, in the Àeld of polymer processing, supercritical technology has already established its effectiveness. Due to their small size, supercritical Áuids penetrate into polymers more easily than do larger liquid solvents. This property facilitates the controlled rapid sorption of SCF through the adjustment of pressure and temperature. Supercritical Áuid used for polymer plasticisation has signiÀcant effects on polymer processing activities which include: (i) separation and fractionation of polymers for extraction of impurities,

6

1.5 Supercritical Water (SCW) Like carbon dioxide, water is readily available and hence of interest as a supercritical Áuid. It is now widely acknowledged that SCW possesses a massive capacity for the destruction of both toxic and hazardous materials. Whilst this interest is currently focused mainly in waste water treatment and the conversion of poorly biodegradable substances to less toxic and more degradable substances, it has also come to the attention of chemists. This is as a potential medium for chemical synthesis and also as a means of polymer recycling. This is because of its special pressure, volume and temperature (PVT) dependencies. As a supercritical Áuid it has a number of interesting and unique properties which are related to its dielectric properties and the ion product.

1.5.1 Properties: Dielectric Constant It can be seen from Figure 3 that supercritical water is able to operate at a range of dielectric constants as the temperature and pressure is changed. The dielectric constant can be varied in a useful region from about 2 to 30 (although higher values can be obtained) dependent on the pressure and/or temperature. The SCW can be controlled to give a dielectric constant representing polar to non-polar properties across this range, mimicking the polarities of numerous common solvents which occur. In comparison to common solvents, hexane (non-polar) is 1.8, carbon tetrachloride has a dielectric constant of 2.2 and methanol 32.6 (polar). It therefore has a higher solubility for organic substrates than water under atmospheric conditions and can dissolve parafÀn, aromatics and gases. At the critical point, it will appear as a weak polar solvent.

Polymer Processing with Supercritiical Fluids

Figure 2 Effect of supercritical carbon dioxide on amorphous polymers

Table 3 Summary of the effects and applications of scCO2 on amorphous and semi-crystalline polymers Gas absorption Plasticisation effect Crystallinity Common examples Potential applications

Semi-crystalline Low (only in amorphous regions) Low (only in amorphous regions) Small increases may be seen (only in amorphous regions) Nylon 66, PVDF, PP, HDPE Replacements for CFCS in cleaning applications (limited applications as amorphous dependent on degree of crystallinity)

1.5.2 Properties: Ion Product The catalytic properties are also enhanced in the supercritical state. The proton concentration increases greatly, by about 30 times, which allows the SCW to replace other acid catalysts. This change in activity is represented by the ion product which is the product of the hydrogen ion concentration and the hydroxy-ion concentration. This is deÀned as Kw = [H+][OH-] Under standard temperature and pressure, this has a value of 1 x 10-7 mol/l for both molecules, the value for Kw will therefore be 1 x 10-14 (mol/l)2. Under high

Amorphous High High Increased ABS, HIPS, PC, PMMA, PET Foaming and production of microcellular structures, impregnation, surface modiÀcation, introduction of crystallisation

temperatures and pressures, the value of the ion product will be considerably increased, giving the acid catalysis effect. The relationship to the dielectric constant at 400 °C is shown in Figure 4. It can be seen from the unique properties of SCW, that the ability to vary the properties of the reaction medium over a wide range of conditions can be achieved simply by changing the pressure and temperature. A reaction can be optimised without changing the solvent, which offers many advantages to chemists. This versatility can be clearly seen in the ability to vary the relative static dielectric constant (¡) and the Kw value with changes to temperature and pressure, since these two physical properties have such a major impact on both the polarity and acid/base-catalytic properties.

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Polymer Processing with Supercritical Fluids

Figure 3 The dielectric constant of water as a function of density and temperature

Figure 4 Changes in ion product and dielectric constant as pressure changes at 400 °C

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Polymer Processing with Supercritiical Fluids

With supercritical water high reaction rates can be achieved, due to the combined properties of high dissolving capacity and high transportability. This means that any mass transfer restrictions due to phase boundaries do not apply with compounds highly soluble in SCW. This is because as a supercritical Áuid it has a high diffusivity and low viscosity to penetrate materials. As well as this, the reaction kinetics can also be varied by pressure. Its pressure and temperature tunability enables good control as a reaction-causing solvent, and has been used for applications such as extraction, decomposition and removal of pollutants in waste water, sludge, coal and oil applications. It has also been the solvent of choice for recovery of waste plastics during chemical recycling.

are certain process advantages with microcellular foaming which can make this the gas of choice (see Section 3.2).

However, the use of SCW does have drawbacks. High investment costs are required due to the high working pressures, and the highly corrosive nature of SCW means expensive barrier materials are required when working with this material. However, despite these drawbacks SCW has great potential for the future especially in the Àelds of chemical synthesis and recycling.

2 Polymer Applications of Supercritical Fluids

1.6 Supercritical Methanol Supercritical methanol has mainly been used in the chemical recycling of polymers, as an alternative to SCW. It offers several advantages over SCW in selected applications, these being: •

Lower critical conditions

•

Easier separation of products from solvent (lower boiling point).

1.7 Supercritical Nitrogen Nitrogen (N2), is mainly found in the atmosphere, where it accounts for 78% by volume of the air we breath. Liquid nitrogen has a variety of uses, for example it is the most common cryogenic Áuid used to chill, freeze or store various products and materials. It is also used in various chemical reactions. The use of high-pressure nitrogen gas in the gas assisted injection moulding (GAIM) process is common, and requires pressures of between 10 bar to 200 bar and a nitrogen content of between 98.0% and 99.9%. From Table 1 it can be seen that this is well within the supercritical pressure range. Generally scCO2 is used instead of supercritical nitrogen; however there

Whilst there are other supercritical Áuids as shown in Table 1, at the time of this review none has yet generated any pertinent research or data to merit inclusion in this review. Now that supercritical Áuids themselves have been considered, discussion will now begin on how these materials can be applied to various aspects of polymer processing.

2.1 Extraction and PuriÀcation The increased analytical accuracy of modern equipment for polymer analysis has inevitably increased the scrutiny with which potential contaminants are detected and viewed. This is especially true in the medical device industry, where materials have intimate contact with the body such as implants, catheters and grafts. A number of polymers are used in medical applications, which can contain residual raw materials or by-products of production. In some cases, such as materials made of silicone or polyester-based polymers, these unwanted components can make up to several percent of the material, although this can be removed to some extent during manufacture. There are materials that can be used to remove impurities by dissolution and extraction. Hexane and methylene chloride are two such organic solvents, however they themselves often leave unwanted residues in the material and can alter its characteristics. Therefore, it is obvious that the use of scCO2 will be extremely attractive in these applications and is already currently used in the production of a number of medical components. The inÁuence of scCO2 swells the polymer molecules, this allows the Áuid to penetrate deep into the component and dissolve any unwanted materials or solute trapped within it. The ability to dissolve materials increases with an increase of density, controllable through control of the system pressure and temperature. Of course when the pressure is reduced, all the carbon dioxide is also removed and unlike conventional liquid extraction, the residual solvent in the extracted material is negligible.

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Polymer Processing with Supercritical Fluids

Generally extraction relies on the basic principle that the solubility of a given compound (solute) in a solvent varies with both temperature and pressure. At ambient conditions (25 °C and 1 bar) the solubility of a solute in a gas is generally negligible (and is related directly to the vapour pressure of the solute). In a SCF, however, solute solubilities of up to 10 orders of magnitude greater than those predicted by ideal gas law behaviour have been reported. This is because in supercritical Áuids the solubility of a solute is not just a function of pressure. Solute-solvent interaction as well as the vapour pressure, controls the dissolution reaction. Therefore volatile solids have a much higher solubility in SCF in general, than for example in ideal gases. The ability to further increase the solubility within a SCF extraction process may also be desirable, in order to reduce the amount of solvent required. This may be achieved by adding another component to the mixture. This may be referred as a co-solvent or entrainer. This material will generally have a volatility intermediate to that of the SCF and the solute which enables the reaction to be controlled more precisely and selectively. However, use of extra materials may also change the chemical nature of the SCF and the ability to remove it after reactions must also be taken into account.

2.2 The Basic Principles of SCF Extraction of Polymers The Áuid is compressed to elevated pressures above its critical pressure, to make it supercritical. The polymer is then exposed to the supercritical Áuid and swells. As

the free volume in the polymer is increased, the SCF can penetrate deeply into the matrix and the impurities are dissolved by the supercritical Áuid. As any volatile materials within the feed matrix will then partition themselves within the supercritical phase, these are removed with the SCF during the extraction from the feed system. In the de-pressurisation phase the pressure is quickly reduced and the supercritical fluid and impurities diffuse out of the polymer. The SCF can then be removed by changes to temperature and/or pressure, leaving negligible SCF in the extracted material and the SCF can be recycled by recompression. This system is shown in Figure 5. There are both advantages and disadvantages of using SCFs when compared to conventional liquid solvents for separations. Some of the advantages are: •

The dissolving power of the SCF is easily controlled and manipulated by pressure and/or temperature,

•

No harmful residue is left as solvents are nontoxic,

•

The SCF is easily recovered and recycled from the extract due to its volatility,

•

The ability to sometimes achieve separations that are not possible by traditional processes,

•

Heat sensitive materials can be extracted as low temperatures can be employed.

Figure 5 Basic principle of SCF extraction

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Polymer Processing with Supercritiical Fluids

Some of the disadvantages are: •

An elevated working pressure is required with associated costs and hazards,

•

Whilst recycling and cost savings can be achieved by a recompression of the solvent, equipment installation can be costly and complex,

•

A high capital investment is therefore necessary for equipment.

2.2.1 Choosing Solvent(s) for Supercritical Fluid Extraction (SFE) When choosing a solvent for SFE, many of the parameters are similar to those used in more traditional extraction methods, namely: has good properties, is inert to the Ànal material, can be easily separated and is economic to use. For SCF, this often means that the critical parameters must be achievable without undue cost or complexity. For this reason carbon dioxide is the most commonly used SCF in SFE, due primarily to its low critical parameters, low-toxicity and low cost. Another solvent with high potential is SCW, due to its ability to dissolve organic compounds whilst leaving behind inorganic salts. The opposite effect to its uncritical state. This enables the same solvent to be used for both extractions. Several other SCFs such as hexane and methylene chloride have been used commercially and in research. For example, the petrochemical industry uses organic solvents. However, these materials require explosion proof equipment, increasing the expense of these processes. Other restrictions on solvent choice may also apply, for example the use of one set of highly effective supercritical solvents (chloroÁuorohydrocarbons, CFCs) is limited due to their effect on the ozone layer. Use of carbon dioxide or water in the form of supercritical Áuids is used as a substitute for organic solvents in both the food and medical industries. SCFs are used as safe alternative solvents in the food processing industry. They are also used in the rapid extraction of spirits and other components at room temperature. Other areas of application include:

(ii) puriÀcation and separation of substances such as oil and grease and (iii) removal of impurities in chemical materials (195). Conventionally, the puriÀcation of polymers is carried out by either vacuum, steam stripping or solvent extraction. However, these methods are not always adequate as they come short in reducing the residual contents to the required permissible levels. Alternatively, devolatilisation with supercritical Áuids can improve impurity removal due to an increased thermodynamic driving force and improved molecular diffusivity. It is therefore more effective. This method can also be used to remove additives, residual solvents, catalysts, and side reaction products which can have a detrimental effect on the end-use properties. Since supercritical Áuids are ‘tuneable’, selective extractions can be carried out providing the SCF has sufficient solubilising power with the product to be puriÀed.

2.2.2 Applications of SFE Several applications for SFE outside the polymer industry have been commercialised, for example in the food industry to decaffeinate tea and coffee, extraction of oils, hops and aromas. Tobacco can be denicotined with this process. A process called Residum Oil Supercritical Extraction (ROSE) is used to remove impurities in the treatment of used oils and lubricants. The pharmaceutical industry uses SFE to extract ingredients from herbal plants, and also eliminate harmful residual solvents from their products. It can also be used to clean contaminated soil and remove residual solvents from waste materials. Supercritical extraction in polymer applications is not widely used yet, but the potential seems high for the polymer industry. One potential application may come in the mechanical recycling Àeld where supercritical Áuids could be used to remove low molecular weight contaminants from recyclate before re-processing. (It is these that often give recyclate such a distinctive smell.)

2.3 Use of SCFs in Polymerisation

2.3.1 Introduction (i) puriÀcation and fractionation of polymers such as the removal of unaffected monomers from polymers

The many attributes of scCO 2 which have been discussed earlier, have made it a viable alternative

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Polymer Processing with Supercritical Fluids

solvent in a number of polymerisation reactions. It has been intensively researched in a wide range of reactions and used as the continuous phase for numerous stepgrowth and chain-growth reactions. This includes freeradical, ionic- and metal-catalysed process routes.

Of all these processes it is the solution, suspension and emulsion type reactions that have attracted most attention for the application of SCF technology, because of the possibility to reduce waste water and/or solvent during polymerisation and to improve properties.

However, the long-term future of its use as a solvent will be limited by the poor solubility of most longchain polymers. Its application is likely to be limited to speciÀc special applications and materials such as Áuorinated polymers, polysiloxanes, and where the reaction involves soluble polymers such as those with a low molecular weight.

It should be noted that bulk polymerisation is by its nature (solvent-free), of no interest to SCF technology, since the objective is to replace solvents that are toxic or reduce waste. However the use of a solvent, as in solution polymerisation, often offers a number of advantages (and some disadvantages too) to a polymerisation process as summarised in Table 4.

Where SCFs have been used successfully, the ability to tailor the properties with scCO2 has enabled the synthesis of polymers with precise control of molecular weight and polydispersity, but with minimal contamination, and at acceptable levels. The morphology can also be controlled in some cases. ScCO2 also offers a potential process route to extremely low residue polymers by acting as a solvent in a number of polymerisation reactions.

A summary of various techniques covered in the abstracts accompanying this review is given in Table 5. It should be noted that all monomers could in theory be processed by any one of the routes highlighted here. However, there are often economic reasons why one or two processes are favoured above others.

In order to fully comprehend the application of SCFs in polymerisation, a quick revision of the various polymerisation routes is now provided. Commercial polymer materials are made by a variety of techniques depending on the required properties and the type of Ànal product. Polymerisation mechanisms can be simply classiÀed into two classes: step and chain. •

•

Step polymerisation proceeds with an increase of one species at a time in any given chain. During the reaction, any of the various sized polymer species present can react with another. The production of polyamides and polyurethane are examples of commercially used step polymerisation processes. With chain polymerisation an initiator is used to produce a reactive species such as a free radical, cation or anion. Monomer then reacts with the reactive species. Polystyrene and polyethylene are two examples of materials that can be made by undergoing chain polymerisation.

Radical polymerisation can be split into homogeneous and heterogeneous types based on the initial mixture. Mass and solution polymerisation are homogeneous; suspension and emulsion polymerisation are heterogeneous processes. A further type of radical chain polymerisation is emulsion polymerisation, which uses monomers in the form of colloidal dispersions.

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Fluoropolymers are already produced commercially using scCO2. The polymerisation reaction is carried out using the emulsion process. The use of SCF enabled the replacement of water and was termed ‘Process G’ by the manufacturers, DuPont. The materials produced were a range of melt processable PTFE resins (151, 153). Due to the higher solubility of materials in SCF compared to some conventional solvents, the range of polymers that can be produced by techniques like solution polymerisation can be expanded somewhat. However with this technique there is a requirement for the materials to be soluble in the solvent, which still means many polymers are not suitable for this route. Generally, this means applications are limited to silicone and Áuoropolymers. For example, DuPont has produced Áuorinated ethylene-propylene with scCO2 as a solvent using the solution polymerisation technique. With dispersion polymerisation, SCF can be applied for synthesis of polymers from monomers such as acrylate and methacrylate (59, 67). Homogeneous polymerisation with supercritical Áuids has also been studied for Áuoroacrylates.

Table 4. Use of solvents in polymerisation reactions Advantages Disadvantages Diluent Purity (residues) Aids heat transfer Chain transfer to solvent Allows mixing Better thermal control

Polymer Processing with Supercritiical Fluids

Table 5. Types of polymerisation reactions Polymerisation process Description conditions Emulsion This is when the monomer(s), initiator, (surfactant) and stabiliser are mixed in the dispersion media to form an inhomogeneous mixture capable of polymerisation of the monomer. Precipitation The polymer precipitates out on forming, as it does not dissolve in the monomer or solvent used. The initial mixture is homogeneous in nature consisting of monomer, initiator and solvent. On polymerisation the reaction becomes heterogeneous. Dispersion This is a type of precipitation polymerisation in which all the necessary ingredients, e.g., monomer(s), initiators(s) and stabiliser(s) are added to a solvent to produce a homogeneous mixture. The resulting polymerisation produces a polymer which does not dissolve in the solvent. This produces polymer particles. Solution This process uses a liquid solvent to dissolve the monomers and initiators. The resulting (co) polymer is often also soluble in the solvent. Suspension

Bulk (can be batch-type or continuous production)

In this method, the monomer(s) droplets are polymerised while being dispersed in a liquid phase (usually water) by continuous mixing. It is primarily utilised for PVC production. This process is also known as mass polymerisation. The monomer is polymerised with an accelerator or catalyst, without any other medium being present. Although the monomers are commonly in a liquid form, they can also be gases or solids if no solvents are present.

As well as the more commonly used scCO2, precipitation polymerisation has also been studied using one of the lesser-used SCFs, supercritical ethane. Unlike solution polymerisation, in this type of reaction it is required that the polymer is insoluble in the solvent being used. It has been used to successfully produce styrene polymers. Another important area of research is in the creation of surfactants for use with SCFs. In dispersion and emulsion polymerisation for example, the surfactants play an essential role in preventing aggregation of the growing polymer chain. With scCO2, many of the traditional surfactants have been found to be insoluble. Therefore increased uptake of scCO2 technology has led to much research, in Ànding suitable surfactants to utilise this new technology.

Polymer types used or produced PTFE, PVDF, PVA, ABS (88, 134, 150)

MMA (polymers and copolymers produced from monomer) (87), acrylonitrile (54), PVDF (89)

PMMA, styrene (59, 86, 96, 304), vinyl acetate, acrylamide

Vinyl acetate, acrylonitrile, PVDF, Áuorinated ethylenepropylene, perÁuoroalkoxy resins, Nylon 6 (125) PVDF, PVA, PE (57, 336)

Ethylene, styrene, MMA

2.4 Impregnation The impregnation of polymeric materials with supercritical fluids is an area of interest in the preparation of novel materials (61, 108). The properties of low surface tension, high diffusivity and the ability to recover the solvent with ease, makes the application of SCF achievable. The impregnation process becomes feasible when the material to be dispersed (the solute) can be dissolved in the supercritical Áuid. The material to be impregnated then swells under the action of the SCF, and the solute within the SCF is dispersed with it. Plasticisation, with the associated reduction in the glass transition temperature aids the impregnation process. Residual

13

Polymer Processing with Supercritical Fluids

solvent recovery can be made relatively easily, when compared to the cost of other solvent recovery options. The process steps are illustrated in Figure 6. Materials that are both miscible and immiscible can become dispersed. A material with little afÀnity for the matrix is dispersed and then trapped when it comes out of solution, but has no molecular attraction with the matrix. The scCO2 appears not to aid compatibility in these cases, in contrast to the effect seen in blending by extrusion for example. A material with afÀnity for the matrix has potential in a variety of applications such as a drug delivery mechanism, for dye impregnation and to produce polymer blends. In all cases it is necessary that the matrix species is able to swell under scCO2. The ability to replace current aqueous dying solvents with an environmentally benign material could reduce textile waste streams considerably. This will be further discussed in Section 2.5. scCO2 can be used to obtain modifications to the polymer molecules, by acting as a carrier for a second impregnated material. By impregnating one material with a monomer and an initiator, the matrix swollen under the effects of the scCO2 is modiÀed, without producing thermal stresses. This allows materials to be manufactured that may be difÀcult to obtain by more common methods. For example Lui and co-workers (107) have reported the polymerisation of styrene monomer within a polypropylene (PP) matrix. This was carried out by impregnating a swollen PP matrix with the monomer and an initiator using scCO2 as the solvent. There has been a similar study with the impregnation of LDPE

using styrene (224), again using the scCO2 to swell the LDPE substrate. After further treatment to induce polymerisation some entanglement between the LDPE/ PS blends could be seen. This technology has numerous possibilities, e.g., (55, 61), outside the range of melt mixing and with thermally unstable materials. For example it is possible to take a hydrophobic material such as PVC and generate a watersoluble polymethacrylic acid (PMAA) within it.

2.5 Supercritical Fluid Dyeing (SFD) A further application for SCF impregnation is to use it as an aid to the dyeing of polymers (212, 214). It offers a number of advantages when compared to the current water processes that require water, surfactants or dispersing aids and need a drying stage. With SFD the production of waste water, which contains remnants of all the additives and unused dye, can be eliminated, as can the necessary drying stage. PP fibres dyed using scCO2 also have a higher dye uptake than with conventional water-based dying systems. Aramid, PE and PET (227) can also all be successfully dyed. Dye molecules tend to be relatively large with slow diffusion rates and they penetrate only into amorphous regions of the polymer. In PP the plastication effect makes the polymer molecules more mobile and this, combined with the high diffusivity of scCO2, leads to higher dye diffusion into the polymer. There has also been considerable success in the dyeing of polyester (179, 200). The high initial investment for this technology means it is the harder to dye materials that will most likely utilise this technology Àrst.

Figure 6 The impregnation process

14

Polymer Processing with Supercritiical Fluids

2.6 Rapid Expansion of Supercritical Fluid Solutions (RESS Process) In the 1980s when a whole number of SCF applications were being explored, one such technology was an exciting new method to produce ultraÀne particles. Even today, this is still an area of intense development by pharmaceutical companies and researchers in the US, Japan (70) and in Europe. This is because the recrystallisation of materials by supercritical Áuid processing enables the manufacture of specially structured products of signiÀcantly high quality and function that simply cannot be produced with conventional manufacturing methods. This is because some pharmaceutical materials are too unstable to micronise by methods such as simple grinding or milling, as they either may form as amorphous materials or just smear. This makes control of the particle size extremely difÀcult. Two methods have been developed to overcome this problem: •

Rapid expansion of supercritical Áuid solutions (RESS) and

•

Supercritical anti-solvent precipitation (SASP)

The RESS process can be used to produce thin Àlm coating, polymer Àbres and Àne graining, by using this process to manufacture whisker-shaped fine particles of a submicrometre size. There is a wide range of different materials that can be processed using RESS technologies including organic and inorganic compounds and pharmaceutical materials. The RESS process is unique, as RESS products are generated ‘dry’, meaning little or no residual solvent. This is because the solvent changes phase during the expansion phase, leaving the deposited supercritical Áuid-soluble materials behind. The process works by exploiting property changes bought about by density changes. By passing supercritical Áuid solutions through a small oriÀce, a rapid expansion occurs, hence the acronym RESS. In this process materials are dissolved in supercritical Áuids that can then for example, be sprayed through a nozzle head and deposited continuously or as required, e.g., micrometre size powder coatings over relatively large areas. In this way it can replace mechanical actions such as grinding or milling to produce Àne deposits, hence preventing damage to delicate materials. Nonpolar materials can be dissolved in supercritical carbon dioxide and then sprayed.

The powder size produced can be manipulated by changes to parameters such as pressure, temperature and concentration. The advantages of carbon dioxide are the same as in other processes. It is cheap, non-toxic and leaves no residue. The rapid expansion stage causes a sudden drop in the dissolving capacity of the solvent as the Áuid comes out of its supercritical state, causing nucleation and growth of any low vapour pressure solute species that were present in the solution prior to expansion. This rapid crystallisation of the solute results in homogeneous submicrometre particles. In many ways the process relies on exploiting pressure drops, similar to the pressure drops employed in a number of SCF technologies such as in extrusion to produce foaming (which will be discussed in the plastic processing section). However, the products here can have a number of different forms dependant on the process settings employed. As in many current SCF applications, the solvent of choice is carbon dioxide; however as in other technologies it may be necessary to modify the properties of the solvent to improve solubility. Therefore modiÀers may be required especially to improve the solubility of polar molecules (e.g., MeOH), since carbon dioxide is non-polar, (but does have a limited afÀnity to polar materials). Co-solvents may also be employed to enhance solubility. A further approach is to add polarity with Áuorinated substituents. However, this can add expense to the process and also make recycling necessary. There are also a number of practical advantages associated with the use of supercritical carbon dioxide as a solvent such as the Ànal dryness achieved by evaporation. This could be essential where residual solvents are problematic such as in pharmaceutical manufacture. This technique is currently employed in the pharmaceutical industry to produce materials such as antibiotics, steroids and controlled release drugs. It is also possible to use supercritical carbon dioxide where there is no solubility, in a complimentary process to RESS called SASP.

2.7 Supercritical Anti-Solvents Precipitation (SASP) This process is also sometimes known as precipitation of a compressed Áuid anti-solvent (PCA). The limited solubility of polar materials in supercritical carbon dioxide has already been discussed. However,

15

Polymer Processing with Supercritical Fluids

supercritical carbon dioxide can still be employed in a powder forming reaction. The SASP process involves Àrst dissolving the material in a suitable solvent. This is then sprayed into the supercritical carbon dioxide, contained in a high-pressure chamber. Droplets are formed and the original solvent dissolves in the carbon dioxide, leaving the insoluble material in powder form. The size of the powder depends on the reaction conditions such as temperature, pressure, and the concentrations of the constituent reaction materials. Like RESS this technique is currently employed in the pharmaceutical industry (106). A further advantage of both the RESS and SASP processes are the extremely fast process times. Gas and solution mixing and pressure reductions can take place in times well below a second. Market opportunity is likely to increase for these technologies and this should also therefore enhance the economics of the process.

3 Processing Applications of SCF Technology 3.1 Plasticisation of Polymers Since it is the plasticisation of polymers using scCO2 which is of major interest in processing, a quick discussion on the effects of plasticisation will now follow. Plasticisers are additives sometimes mixed with polymers to change the rheology and/or the mechanical properties of the Ànal product. Perhaps the best-known use of plasticisers is in PVC where plasticisers can be used to reduce stiffness and lower the glass transition temperature. The effect of this addition depends on the nature of the additive and the structure of the polymer. If the additive is soluble in the plasticiser, then absorption will cause swelling and eventually it will dissolve. The behaviour of molten thermoplastic polymers with supercritical Áuids is of great interest as a substitute for plasticising agents in processing. This is particularly of importance for thermally labile polymers with high glass transition temperatures (Tg) and for materials that are highly viscous. Plasticisation is generally characterised by changes in the polymer system that result in: •

16

a lowering of the glass transition temperature,

•

a lower rigidity at room temperature,

•

increased elongation and Áexibility of individual chains in the polymer,

•

increased toughness.

Amorphous materials and amorphous regions in semicrystalline materials are more easily penetrated than crystalline regions in semi-crystalline polymers. The degree of crosslinking also affects the ability of the plasticiser to penetrate. This can be observed when considering that elastomers (with a less dense network of crosslinks) may swell in a solvent but a thermoset (highly crosslinked) neither swells nor dissolves. During polymer synthesis, plasticisation can generally be achieved either during synthesis by adding a small amount of co-monomer (to disturb the subsequent crystallinity and chain packing), or by adding a low molecular weight compound into a higher molecular weight polymer. In both techniques the result is an increase in the free volume leading to the described changes in physical properties. A further method to induce plasticisation is to include a high-pressure gas, a process called gas-induced plasticisation. When scCO2 is dissolved into a polymer melt the viscosity is observed to decrease. This is obviously of great interest in trying to process high viscosity melts. It also enables temperature-sensitive polymers to be processed at lower temperatures, as well as lower processing temperatures for materials with high glass transition temperatures. As previously described, amorphous polymers swell under the inÁuence of scCO2 and can absorb carbon dioxide to a greater extent than crystalline polymers, and therefore amorphous polymers have an increased potential for both plasticisation and foaming (which will be discussed later). For materials with high viscosities, a lowering of viscosity during processing can be achieved by an increase in the processing temperature. However an increase in temperature can also cause heat degradation, if this requires temperatures above the normal processing range. Therefore an alternative method that could reduce the viscosity of polymers is extremely attractive. This is not only in terms of the drop in viscosity and therefore improvements in processability, but also the ability to reduce the processing temperatures. This allows a drop in energy consumption and therefore leads to cost reductions. Obviously therefore, this is a very attractive proposition to material processors.

Polymer Processing with Supercritiical Fluids

The high pressures required for the containment of SCF within the polymers, are similar to those already encountered in processing operations such as injection moulding and extrusion. Therefore, it is not a great problem to modify these systems for use with a SCF such as scCO2. Also the gas can be easily removed by simply reducing the pressure. Processes developed for use with supercritical Áuids will now be discussed, whilst they are primarily focused on foam applications, the other major beneÀt of using supercritical Áuids (for energy savings) should also be borne in mind throughout.

3.2 Extrusion Standard extruders generally need little modiÀcation to incorporate scCO 2 as this can be introduced through a venting port (114, 118, 228). The scCO2 is injected downstream after the plastic undergoes initial plastication. The two materials then create a single phase through the action of the screw and mixers. The rapid pressure drop at the die initiates cell nucleation. The use of supercritical Áuids in extrusion has focused on two distinct applications: 1. Insulation foams, low density (< 0.4 g/cm3). 2. Microcellular foams, high density (approximately 0.7 g/cm3). The basic steps to foaming remain the same; the differences are in the pressure drop requirements, which control the Ànal cell sizes. For standard foams, conventional equipment can generally be used providing supercritical Áuid is introduced and adequately mixed prior to foaming. Under these conditions a standard extruder would generally be expected to produce low quality foam with large irregular cell sizes. These extrusions would have the same drawbacks as conventionally produced cellular materials using chemical-blowing agents, i.e., poor and irregular surface Ànish. For microcellular production, the pressure drop is more tightly controlled, by design and modiÀcations to both the screw and die. This enables maintenance of an adequate pressure within the system and ensures that a sufÀcient pressure drop is present when the material exits through the die. The Àrst step in extrusion is the injection of the physical blowing agents in a supercritical state. Carbon dioxide

(CO2) is the most common blowing agent but nitrogen (N2) is also used. This can be injected directly into the molten polymer in the extruder. By using these gases in supercritical states both a higher diffusivity and a higher solubility in the polymer can be achieved. A variety of injector systems are available, the main prerequisite being that they can deliver a controlled dose of the Áuid, to the barrel of the machine. The second step requires the saturation, mixing and dissolving of the SCF into the molten polymer to create a single-phase homogeneous polymer/gas solution. A number of different methods of mixing the polymer and gas have been studied. For example Rapra has done work on dispersing the SCF in the polymer, using both a static mixer and a cavity transfer mixer (CTM) (228). The work proved to be successful and was later applied to injection moulding for the Foamold process (see Section 3.3.4). Research has also been carried out to assess the feasibility of making compounds of gas encapsulated polymers, providing a gas/polymer ‘pre-mix’ to enable processing/foaming to be carried out without the need for further gas additions. The permeability of the polymer and hence gas diffusion and potential shelf-life of these compounds is obviously a limitation here. In terms of the extrusion processing itself, it has been found that the gas diffusion process depends on solubility, diffusion rate and extrusion parameters such as foaming temperature and saturation pressure (in order to promote the development of a microcellular structure). The Ànal step is the foaming as the material exits the die. The die has a dual function as it must maintain an adequate pressure in the extruder barrel to keep the blowing agent from coming out of solution. It must also provide the appropriate rapid pressure drop rate to bring the SCF back out of solution. At this stage there is nucleation, and gas nuclei form throughout the polymer matrix as the materials are split back into two phases. This is followed by a cell growth phase that relates to the growth and development of the cells. This is controlled by a combination of mass transfer and Áuid dynamics which is beyond the scope of this review. Depending on the parameters employed during processing, a variety of conventional size cells or microcellular cells will result. Some of the important parameters in SCF foaming are highlighted in Figure 7.

3.2.1 Microcellular Foams Since microcellular foams are of such high commercial interest, further discussion on their unique properties will now follow.

17

Polymer Processing with Supercritical Fluids

Figure 7 Important parameters in the extrusion foaming process

A microcellular foam is characterised by its cell size (smaller than 10 μm) and the cell density (density >109 cells/cm3). These materials have a more consistent and homogeneous cell structure compared to the cell size and structure of standard foam. These bring a number of advantages, including better physical properties such as improved impact strength and toughness. This means that when compared to common structural foams these materials have a higher weight to mechanical strength ratio. They also beneÀt from an improved surface appearance, low dielectric constant and improved thermal insulation. Another important beneÀt of this process is the ability to replace unfoamed applications which do not require the full mechanical properties achieved with unfoamed materials. This allows manufactures to achieve both material and weight savings. In order for microcellular foaming to be achieved, the supercritical Áuid and polymer must Àrst create a singlephase solution. For this, the CO2 needs to be dissolved with the polymer at high pressure, the solubility being pressure dependent. Lowering the pressure to below the saturation point will bring the CO2 out of solution. To create microcellular foams it is necessary for a large number of cells to be created before any increase in the size of those cells occurs. This can only be produced with a cell nucleation rate that is extremely high and higher than the diffusion rate of the blowing agent into cells (i.e., cell creation as opposed to cell growth). With a large number of nucleation sites in place, growth can then occur simultaneously and at the same rate. It is this relationship that gives the evenly distributed, uniformly

18

sized, microscopic cells than characterise microcellular moulding. There is little data available on the critical pressure drop required for microcellular foaming. For high impact polystyrene (HIPS), it is reported as being around 109 Pa/s. However such critical pressures are likely to be highly material dependant due to factors such as crystallinity, branching and additives which can all affect the number of available nucleation sites. The pressure drop in a system can be calculated as follows: dp 32μD4V2 = dt d6

where D = screw diameter, μ = material viscosity, d = nozzle oriÀce diameter, V = extrusion speed/injection speed. As the screw speed is increased the pressure drop also increases. The critical pressure required to create microcellular foams is however also related to the gate size (in injection moulding), the material, the gas percentage and the melt temperature. In injection moulding, which will be further discussed later in this review, there is a clear link between injection speed and potential weight reduction. Higher speeds lead to more foaming as there are considerably more cells produced at a higher injection speed. This is due to an increased pressure drop in the tool at a faster speed. At a further increased injection speed the pressure drop would continue to rise and more cells would be achieved until a saturation point was reached. It is the rate of pressure

Polymer Processing with Supercritiical Fluids

reduction which controls the time period for nucleation and growth. Under unsaturated process conditions, a higher pressure drop may be required to increase the nucleation rate. This can be achieved with the design of the nozzle and with consideration of factors such as tooling.

2. A proprietary screw design is used to disperse and intimately mix the SCF and the polymer to form a single-phase solution. A pressure proÀle is required to keep the SCF in solution and to ensure the availability of sufÀcient nucleation sites when the material exits the die.

In terms of service strength, the compressive strength of the foams depends on the cell size, as it has been found that the compressive strength increases with increasing cell size. The compressive force causes progressive buckling of the microcellular cells (319).

3. A suitably designed die will ensure there is control of the microcellular foaming when the material exits the die.

3.2.2 MuCell Extrusion Technology

3.3 Injection Moulding

Microcellular foaming was Àrst offered for extrusion commercially by Trexel under the trade name MuCell Extrusion Technology. This system provides both the equipment and processing technologies for producing microcellular foams using thermoplastic materials and can currently only be used under license. It can be installed in both new and existing extrusion equipment. As in conventional foaming, the MuCell Extrusion Technology is based on three stages, but the process requires the purchase and modiÀcation of several pieces of proprietary equipment:

Trexel along with others, have also successfully commercialised microcellular moulding in injection moulding. As in extrusion, all the systems represented here assume the creation of a single-phase of polymer and gas with a solubility gradient.

1. A Trexel SCF System provides the Áuid pumping and a MuCell® Injector Kit is used to inject the supercritical Áuid directly into the extruder barrel.

A diagram of a potential setup is shown in Figure 8.

scCO2 and supercritical nitrogen are currently used as foaming agents in injection moulding to produce lightweight components with high mechanical strength. The higher solubility of scCO2 is advantageous, however supercritical nitrogen can sometimes be used to produce a better surface Ànish and smaller cells. As with extrusion, to produce microcellular foams a higher pressure drop is required than with conventional foaming. This is to increase the number of nucleation sites.

Figure 8 Design for a MuCellTM system

19

Polymer Processing with Supercritical Fluids

3.3.1 Trexel: The MuCellTM System (166, 167)

•

An injection moulding system using scCO 2 is commercially available by licence from Trexel Inc., Woburn, MA. The technology is known as MuCellTM. There are numerous claims made for this process, for example it is claimed that this technology can lower the viscosity of the melt, allowing temperature reductions of up to 78 °C (especially useful if processing heat sensitive materials such as PVC leading to both reduced energy consumption and less chance of material degradation). There is also an associated reduction in the cavity pressure that is produced in the tool. This can allow an increase in the number of cavities, and hence improved manufacturing efÀciency. The MuCell TM process configuration includes a speciÀcally conÀgured screw and feed system designed to optimise the thermodynamic instability necessary to achieve rapid foaming. Carbon dioxide is introduced into the injection barrel to form a single-phase solution with the polymer melt. The following equipment is required to run MuCellTM: •

metering system for the supercritical Áuid (SCF) to ensure the Áuid is at the appropriate pressure and volume.

•

A Trexel designed screw and possibly new barrel.

Software and system modiÀcations to create and maintain the uniformity required of the single-phase solution through the injection moulding cycle.

The screws are usually 22:1 or 24:1 L/D with the barrel Àtted with injector systems designed to match the screw length. A shut-off nozzle and screw position control modiÀcations are used to help maintain the pressure for a single phase solution and prevent decompression. A system is shown in Figure 9. As with the Trexel extrusion technology, this system also requires the purchase of both a licence for the technology and any necessary machine modiÀcations. The next system attempts to introduce the material into the nozzle rather than the barrel, making the change to foaming much simpler and cheaper. It is much newer and therefore less established than the Trexel system, but also enables further understanding of the basic requirements for microcellular moulding.

3.3.2 Ergocell In 2001, Demag Ergotech Àrst showed its new Ergocell process for moulding microcellular foamed products. To overcome any possible patent conÁicts, they made an agreement with Trexel that makes it necessary for Ergocell customers to purchase a MuCell licence, however these are offered at reduced cost. As part of the agreement Demag also offer customers injection presses with a MuCell option.

Figure 9 MuCellTM system

20

Polymer Processing with Supercritiical Fluids

Unlike MuCell, which injects the gas part way along a specially modiÀed screw, the Ergocell process injects gas downstream of the plastication screw into an already fully homogenised melt. This process works by splitting the plasticising, gas mixing and injection stages into separate functions. Plasticising proceeds as normal but a mixing chamber is added on at the end of the screw to inject the gas and blend the gas/polymer mixture. A melt accumulator then holds the material under pressure until it is injected. This is achieved using conventional equipment: a standard injection cylinder and screw, and a non-return valve. This is because all the necessary work is carried out in a bolt-on unit Àtted to the end of existing machinery. Ergocell technology equipment is made up of: •

A module for gas metering and mixing (including a mixer, injection module and non-return valve).

•

An injection accumulator.

•

A gas station (a source of gas, carbon dioxide or nitrogen is also required by the user).

•

A gas metering and mixing module.

The function of the module is to ensure effective homogenising of the melt/gas mixture independent to the plasticising stage. It consists of an injection plunger which is attached to the existing plasticising screw. This then leads to a mixer where the gas nozzles are arranged

opposite each other. The mixer external geometry is splined to the plunger. A schematic of the module is shown in Figure 10. As the polymer is passed down the screw, gas delivery takes place simultaneously with plasticising of the next shot. Gas is fed from the metering station into the melt as the screw draws feed material in, and is pushed back by the back pressure. This feeding of material pushes existing material into the mixer and injection module. The melt here is intimately mixed with the CO2. The melt accumulator then holds the mixture under pressure until the nozzle valve is opened and the plunger injects the melt into the mould. scCO2 is the recommended blowing agent with this process, due to its high sorption capacity in polymers. Whilst nitrogen can be used, lesser weight savings are obtainable. The microcellular structure produced has realised material savings of up to 40 percent. Also, as in other injection moulding supercritical applications the gas reduces the viscosity of the material enabling reductions in injection pressure and clamping forces. The main differences in the Ergocell and MuCell systems are in the point of gas injection. Because of the design of Ergocell, it can be retroÀtted to Ergotech machines and also removed when necessary to use the machine in its standard conÀguration. The hardware itself does not require a licence as the MuCell system does. There is also the likelihood of less shear damage to the material, due to the nature of the mixing system, as the melt is not mixed in the screw but by a mixer.

injection piston

spine

screw

melt polymer gas (single phase) gas injection nozzle

Figure 10 Ergocell module

21

Polymer Processing with Supercritical Fluids

This also allows a wider processing window for many material applications. As summarised in Table 6, the other advantages of this process are the same as for MuCell technology.

3.3.3 Optifoam Process A further bolt-on system has been commercialised by Sulzer Chemtech Ltd. In this system gas is introduced in a specially designed injection nozzle rather than the barrel as in the MuCell system. This nozzle is shown schematically in Figure 11 and is mounted between the plasticising unit and the shut-off nozzle of a conventional machine in a similar manner to the Ergocell system.

Table 6. Advantages of microcellular mouldings over standard injection mouldings Process Reduction in part weight advantages Elimination of sink marks Control of warpage Lower internal stresses Improved insulation (thermal and acoustical) Dimensional stability Specially suited for decorating techniques Cost advantages Material savings Reduction in clamping force Reduction in cycle time

In order to produce a homogeneous distribution of gas in the melt a ring shape die design and a torpedo is used at the centre of the melt Áow channel to enlarge the mixing area. This is manufactured using sintered metal which is permeable to the gas. Static mixers downstream of the Áuid entrance point ensure intimate polymer/gas mixing is achieved. The results reported so far by IKV Aachen, Germany who initially developed the process, relate to the importance of the relative injection moulding parameters. Injection speeds, melt temperature and the concentration of the blowing agent are considered the key machine settings with this system. With an 8 mm wall thickness a density reduction of up to 66% was achieved using this system with polystyrene. (However, generally with all foaming methods, larger weight reductions can be achieved with thicker cavities. This correlation seems independent of the material type.) A further application for the Optifoam process achieved a 63% density reduction. This was on a thermoplastic polyurethane shoe sole (a.2). Like the Ergocell design, this can be retroÀtted to all injection moulding machines but unlike any of the processes so far, is license free.

3.3.4 Foamold The Foamold system by Rapra Technology Limited claims to be the world’s Àrst portable injection moulding machine with scCO2 foaming capability(188). The gas injection unit can be used either for foaming or as a means of lowering the viscosity of the molten material to allow easier mould Àlling and improved product

Figure 11 Optifoam gas injection nozzle schematic

22

Polymer Processing with Supercritiical Fluids

quality. Unlike other systems, the Foamold system uses both a cavity transfer mixer (CTM) and an internal static mixer to disperse the gas in the melt. Previous research carried out by Rapra on extrusion had shown the necessity to maintain uniform processing conditions. This was achieved by separation of the screw preplasticiser and the ram injection pot. The system, known as Foamold includes a cavity transfer mixer (designed and developed at Rapra) and a static internal mixer, to ensure near perfect dispersion of the gas in the melt. The small machine can deal in sample weights in the range 0.02-12 g. Lower processing temperatures (meaning less thermal degradation), lower injection pressures and shorter cycling times means there is a great potential for energy savings.

a lesser dependency on the supercritical Áuid level employed in processing.

3.4 Microcellular Blow Moulding Microcellular blow moulding has also been proposed by Trexel Inc. (196). Like the injection moulding and extrusion processes already commercialised by Trexel, the SCF is injected into the extruder. The process is preformed in the normal sequence and foaming controlled by modiÀcations to the die and screw.

3.5 Blending 3.3.5 Applications and Properties of Microcellular Foams Most materials can be produced with a microcellular structure, including amorphous, semi-crystalline and thermoplastic elastomer (TPE) materials (64). Therefore there are numerous applications reported for this technology of which some now follow: automotive fasteners and door latches, automotive interior trim, air distribution manifold, engine intake manifold gasket, automotive fuse box, rear air blower base connector, fan motor housing, printer components, electrical switches, electrical box, electrical connector, cable ties, child gate panel, thin-wall container, bottle cap, and thermoplastic vulcanisate weatherstrips (82). For the same reasons as stated in Section 1.4.1, it is difÀcult to deÀnitively give the properties of microcellular materials as they are so dependent on the particular process and material combination. However, Table 7 is a guide to the potential for the change of properties with microcellular processing when compared to standard techniques. The weld-line properties of injection moulded microcellular materials are affected by processing conditions similar to conventional injection moulding (129), that is increased strength with increasing melt temperature, injection speed and shot size. The weldline strength of microcellular materials also showed

Blends are extremely important materials, which can provide materials with properties not available from using a single material. Blends are produced by mixing or blending polymers together. Examples of common commercial blends are PVC-ABS or PC-ABS. These materials are not to be confused with copolymers, which are polymeric materials composed of one or more monomers in the same chain, e.g., high impact polystyrene (HIPS) or ABS which is a terpolymer (three different monomer groups), made up of a blend of acrylonitrile, butadiene and styrene. These types of materials would be produced by polymerisation routes as dealt with in Section 2. Successful polymer blending often depends on the very different viscosities of the polymers. For example a low viscosity polymer with a small quantity of high viscosity polymer can improve a number of properties such as the impact strength or the tear strength. Blends can be of two types: miscible (one phase) and have a single glass transition temperature or immiscible (two phases) with two glass transition temperatures. Most useful blends of two polymers are immiscible and hence form two phase systems (one phase rich with one material and another phase rich in the other material). The blend may be made up predominately of one of these materials, whilst the second component is dispersed within it. The level of dispersion plays an important part in determining the blend properties,

Table 7. Microcellular plastic compared to unfoamed (solid) material Properties Unfoamed plastic Microcellular plastic SpeciÀc density ratio 1.0 0.05-0.95 100 35 (PS with 10% CO2) Glass transition reduction, Tg (°C) Viscosity ratio (viscosity foamed/viscosity unfoamed) 1.0 0.20 (PS with 4% CO2)

23

Polymer Processing with Supercritical Fluids

particularly the particle size of the dispersed material. This is determined by the shearing action at blending but also depends on the surface tension of the material. Additives can be used to improve the stability of the material interface, they are called compatibilisers. They work by reducing the surface tension and hence the particle size between the dominant phase and the dispersed phase. They also help to prevent the particles from coalescing. When used in the creation of blends using an extruder, scCO2 can enable the beneÀts of compatibilisation to be achieved. Namely, whilst it does not dissolve most polymers, it is a very effective plasticiser affecting both the viscosity and the morphology. When a SCF is absorbed it causes swelling, reduced chain entanglement and the free volume is increased. Due to the properties of both the SCF (high diffusivity) and the polymer (swelling under SCF), a high level of penetration of the SCF is possible. Interfacial tension is reduced, reducing the strength between phases. The plasticising effect of the SCF also causes a reduction in the viscosity. This plasticising effect tends to cause polymer speciÀc viscosity reductions so in some cases reduces one component more than the other. This enables the viscosity ratio of the two components to be inÁuenced. A matching of viscosity ratio is beneÀcial to mixing and therefore also affects the dispersion parameters. These properties all lead to a reduction in particle size of the dispersed phase, thus improving the blend. With PS/LDPE blends extruded with 4% wt scCO2, it was found that the SCF reduced the size of the dispersed phase (103). However the current problem with using extrusion blending technology using SCF is that once the SCF is vented, the blends show the properties of untreated blends.

The process details have yet to be published, subject to patent applications. From reports that are available it appears they are using SCF as a plasticiser and are using scCO2 and methane as solvents in a process to ultimately deposit a ceramic on the surface of the polymer via a sol-gel process. Whilst the creation of a polymer-ceramic matrix is not new, incorporation of SCF into the process would suggest that a large process and hardness improvement should be achievable.

5 Recycling and Recovery With worldwide consumption of plastics increasing annually, and with Àfty percent of the mixed solid waste stream consisting of these materials, the opportunities for recycling and recovery of polymeric materials are high. In this regard SCF technology has been applied to these areas (102, 402).

5.1 Mechanical Recycling One application of SCF that may prove commercially viable to the recycling industry is as a cleaning agent to remove contamination from the polymer prior or during mechanical recycling. For example, supercritical Áuids can be used to clean polyethylene automotive fuel tanks of residual gasoline or diesel (56). A gas tank may absorb up to 5% by weight of fuel over the course of its service life. By pressurising the shredded materials and exposing them to scCO2, the gas acts as a solvent to extract the residual fuel. Supercritical fluids can also be used during recompounding to remove contaminants (373). Controlled experiments with naphthalene doped plastics found 95% or greater of the naphthalene could be removed by introducing SCF into a 34 mm counter-rotating, intermeshing twin-screw extruder.

4 Hardening of Polymers

5.2 Chemical Recycling

A further application for supercritical Áuids has been reported by Rosti Medical Plastics (25). They have announced a new product called Hard-Plas. This aims to replace traditional metal materials, primarily in medical applications, by producing disposable polymer scalpels to replace metal ones. This would remove the current contamination problem. It is reported that a hardness equivalent to quartz has been achieved.

Unlike mechanical recycling, which collects and uses waste plastics without any further chemical treatment, chemical recycling uses the waste products to turn them into their monomers (or other useful chemicals) by means of chemical reactions. Common examples of chemical recycling processes include cracking and hydrogenation. Thermal conversion technologies on the other hand generate conversion products and heat.

24

Polymer Processing with Supercritiical Fluids

These are used for both a volume reduction in the waste and for energy recovery. There are three common types of categories of reactions, distinguished by their air requirements: •

Pyrolysis: thermal processing in the absence of oxygen. (Pyrolysis conditions have found few commercial applications because of high viscosities and low heat transfer rates.)

•

Hydrogenation: as pyrolysis but in a high hydrogen or carbon monoxide environment.

•

GasiÀcation: partial combustion with a limited air supply.

In this respect chemical recycling would appear to offer ideal recycling routes for thermoset resins that cannot be recycled by reprocessing like thermoplastics can. However, their highly crosslinked nature can make them difÀcult to depolymerise and generally chemical recycling is more suited to polymers such as PET, PA and PU. An alternative disposal method for hazardous or toxic materials is the supercritical oxidation processes. These are ‘green’ technologies since they operate as closed processes and hence no emissions to the atmosphere occur. Epoxy resin, polyetheretherketones and xylene resin can all be decomposed back into monomers using SCW (73). Likewise, phenol resin can be recycled using SCW and supercritical methanol. Using SCW with appropriate oxidisers under hydrothermal conditions, components can be decomposed to simpler materials such as carbon dioxide, nitrogen and water. This is a highly efÀcient ‘combustion’ system with efÀciencies >99.9%. Since the critical point of water is relatively high (374 °C) and its properties vary signiÀcantly as discussed in Section 1.5, easy control can be achieved over reaction pathways and reaction rate.

can be considerably improved, also no additive or compatibilisers are required with SCW. This should lead to a process that is more efÀcient than the conventional process for PET decomposition. Recently the effect of supercritical ammonia on polycarbonates has also been studied (52). Polyamide (161) has also been decomposed with SCW, as have flame retardant additive containing epoxy materials (162). In this case the SCW enabled accelerated bromine abstraction for the plastic to be achieved.

6 Conclusions The use of supercritical Áuids in the polymer industry presents an opportunity to create unique products both now and in the future as demand and usage of the technology further develops. The choice to change to supercritical processing technology will depend primarily on the demands of the marketplace and the economics of the technology versus existing processes. A switch to a high-pressure technology requires both investment cost and the desire to tackle what may be a highly complex process. Market demand may come in the form of improved product performance/ speciÀcations or environmental legislation affecting factors such as purity and/or recycling and disposal. A market may also exist for products which realistically cannot be manufactured by alternative process routes. The extent to which SCF technology will be applied in the polymer industry has yet to be realised, but the massive research effort currently being put into the numerous and varied potential applications makes further utilisation of these processes highly likely.

Polyethylene has been decomposed using SCW in a reaction using pyrolysis and partial oxidation (164); silane-crosslinked PE was likewise decomposed using supercritical methanol (160). Thermoplastic polyethylene terephthalate (PET) can be decomposed by hydrolysis. Conversion methods proceed by methanolysis or glycolysis. The hydrolysis of PET generates terephthalic acid and ethylene glycol. By using hydrolysis with supercritical water or supercritical methanol (171) the reaction time

25

Polymer Processing with Supercritical Fluids

Additional References a.1

K.M. Scholsky, Process Polymers with Supercritical Fluids, Chemtech, 1987.

a.2

Sulzer Technical Review, Sulzer Chemtech Ltd., 2004.

26

References and Abstracts

Abstracts from the Polymer Library Database Item 1 GPEC 2004: Plastics - Helping Grow A Greener Environment. Proceedings of a conference held Detroit, Mi., 18th-19th Feb.2004. BrookÀeld, Ct., SPE, 2004, Paper 27, pp.6, CD-ROM, 012 AROMATIC HYDROCARBON CONTENT OF COMMON PLASTIC PACKAGING MATERIALS Ezrin M; Lavigne G Connecticut,University (SPE,Environmental Div.) Various plastics packaging materials containing readily detected levels of aromatic hydrocarbons were subjected to supercritical Áuid extraction with carbon dioxide to remove the hydrocarbons and then exposed to atmosphere to allow them to reabsorb hydrocarbons from the air either in a Áask or garage. The plastics packaging materials were analysed before extraction, after extraction and after exposure to hydrocarbons in the atmosphere by thermal desorption gas chromatography/mass spectroscopy using heat to evolve volatile compounds onto the chromatography column. The materials were found to absorb hydrocarbons from the atmosphere. The most likely source of the absorbed hydrocarbons was identiÀed as gasoline vapours. USA

Item 3 Polymer Science Series A 46, No.4, April 2004, p.377-80 SYNTHESIS OF POLYIMIDES IN SUPERCRITICAL CARBON DIOXIDE Said-Galiyev E E; Vygodskii Y S; Nikitin L N; Vinokur R A; Khokhlov A R; Potoskaya I V; Kireev V V; Schaumburg K Russian Academy of Sciences; Mendeleev University of Chemical Technology; Roskilde,University High molecular-mass polyimides are synthesised in supercritical carbon dioxide by the one-step polycyclisation of diamines and tetracarboxylic dianhydrides under batch and Áow regimes. The effect of various reaction parameters (including the content of water in the reaction system) on the structure, molecular mass and yield of polymers is studied. It is shown that the solubility of monomers in supercritical CO2 is indecisive for polymer growth. It is hypothesised that CO2 exhibits catalytic activity when polyimides are prepared in the presence of water. 11 refs. DENMARK; EU; EUROPEAN COMMUNITY; EUROPEAN UNION; RUSSIA; SCANDINAVIA; WESTERN EUROPE; WESTERN EUROPE-GENERAL

Accession no.922515

Accession no.923279 Item 2 GPEC 2004: Plastics - Helping Grow A Greener Environment. Proceedings of a conference held Detroit, Mi., 18th-19th Feb.2004. BrookÀeld, Ct., SPE, 2004, Paper 49, pp.10, CD-ROM, 012 DEVULCANIZATION OF RECYCLED TIRE RUBBER USING SUPERCRITICAL CARBON DIOXIDE Tzoganakis C; Zhang Q Waterloo,University (SPE,Environmental Div.) An investigation was carried out into the devulcanisation of crumb rubber from recycled truck tyres in a twinscrew extruder into which supercritical carbon dioxide was injected to swell the crumb rubber. The effects of the supercritical carbon dioxide on extrusion and of processing conditions (Áow rate, carbon dioxide concentration, screw speed and conÀguration and temperature) on the viscosity and degree of devulcanisation of the rubber were examined and chemical changes occurring during devulcanisation assessed using FTIR spectroscopy. 14 refs.

Item 4 Journal of Cellular Plastics 40, No.5, Sept.2004, p.371-82 CELL DEVELOPMENT IN MICROCELLULAR INJECTION MOLDED POLYAMIDE-6 NANOCOMPOSITE AND NEAT RESIN Chandra A; Gong S; Turng L-S; Gramann P Wisconsin-Madison,University; Madison Group The effects of processing parameters and nanofillers (nanoclay) on cell nucleation and cell growth during the injection moulding of microcellular polyamide6 nanocomposites were investigated using various techniques. A fractional four-factorial, three level, L9 Taguchi design of experiments was performed to minimise the number of trials and facilitate the analysis of the results and morphology development of cell structure was analysed by scanning electron microscopy. Processing parameters studied included melt temperature, injection speed, supercritical Áuid concentration and shot size. (ANTEC 2004, Chicago, Illinois, 16th-20th May) 8 refs. USA

Accession no.922671

CANADA

Accession no.923300

© Copyright 2005 Rapra Technology Limited

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References and Abstracts

Item 5 Macromolecules 37, No.11, 1st June 2004, p.4241-6 CHARACTERIZATION OF POLYETHYLENES PRODUCED IN SUPERCRITICAL CARBON DIOXIDE BY A LATE-TRANSITION-METAL CATALYST de Vries T J; Kemmere M F; Keurentjes J T F Eindhoven,University of Technology

Item 7 Journal of Applied Polymer Science 93, No.2, 15th July 2004, p.545-9 NEW PDMS MACROMONOMER STABILIZER FOR DISPERSION POLYMERIZATION OF STYRENE IN SUPERCRITICAL CARBON DIOXIDE Ruolei Wang; Cheung H M Akron,University

Polymerisation of ethylene in a supercritical carbon dioxide (scCO2) medium, using a palladium based catalyst, was studied over a range of temperatures, pressures and ethylene concentrations. Polymers were characterised using gel permeation chromatography, differential scanning calorimetry, and nuclear magnetic resonance spectroscopy. High molecular weight amorphous polymers with narrow molecular weight distribution and a high degree of branching were obtained, similar to those obtained from solution polymerisation in dichloromethane. Degree of short chain branching was higher when sc CO2 was used, and evidence of a new branch-on-branch structure was observed. Molecular weight, but not short chain branching were affected by polymerisation temperature and ethylene concentration. 22 refs.

A polydimethylsiloxane(PDMS) macromonomer was used as a stabiliser for free radical dispersion polymerisation of PS in supercritical carbon dioxide. The reactions were conducted in a 225 mL stainless steel autoclave over the temperature range 60 to 80C and under pressures of 1500 to 3000 psi. The effects of the stabiliser concentration on conversion, molec.wt. and product morphology were investigated. After 2 to 12 h of polymerisation, the conversion determined by the gravimetric method was between 20 and 80%. These preliminary results indicated that the macromonomer provided satisfactory stabilisation for the styrene system. 14 refs.

EUROPEAN COMMUNITY; EUROPEAN UNION; NETHERLANDS; WESTERN EUROPE

Accession no.921548 Item 6 ANTEC 2003. Proceedings of the 61st SPE Annual Conference held Nashville, Tn., 4th-8th May 2003. BrookÀeld, Ct., SPE, 2003, Volume 1-Processing Session M13-Recycling, p.2811-5, CD-ROM, 012 MELT PROCESSING OF THERMALLY UNSTABLE POLYMERS PLASTICIZED WITH CO2 Bortner M J; Wilding M D; Baird D G Virginia,Polytechnic Institute & State University (SPE) An acrylonitrile copolymer was plasticised using supercritical carbon dioxide, so as to reduce the melt viscosity and allow melt spinning at temperatures below those at which signiÀcant crosslinking occurred. The copolymer (65 mol% acrylonitrile, 25 mol% methyl acrylate and 10 mol% rubber), in pellet form, was exposed to carbon dioxide at 11 MPa and 120 C for various time periods and characterised by differential scanning calorimetry and capillary rheometer measurements. A plasticising effect was observed, with a nonlinear pressure dependence, indicating that further plasticisation would occur at higher pressures. 14 refs.

USA

Accession no.920957 Item 8 E-Polymers No.2, 2004, p.1-7 SOLVATION OF POLY(METHYL ACRYLATE) AND POLY(VINYL ACETATE) BY CO2 STUDIED VIA ATOMISTIC MONTE CARLO SIMULATION TECHNIQUES Beuermann S; Buback M; Drache M; Nelke D; Schmidt-Naake G Clausthal,Technical University; Gottingen,GeorgAugust-Universitat The differences in solubility of PVAc and polymethyl acrylate(PMA) were studied by using atomistic Monte Carlo simulation techniques. Polymer segments consisting of nine monomer units served as model compounds for polymer chains. As a measure of intermolecular interactions with the solvent environment, cohesion energies of the polymer segments embedded in either the corresponding monomer or in carbon dioxide were calculated. SpeciÀc interactions between polymer segments were identiÀed only in the case of PMA segments in carbon dioxide environment. This result was in agreement with experimental results on phase behaviour and propagation kinetics. 15 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.920167

USA

Accession no.920541

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References and Abstracts

Item 9 E-Polymers No.3, 2004, p.1-14 REVERSIBLE ADDITION FRAGMENTATION CHAIN TRANSFER(RAFT) POLYMERIZATION OF STYRENE IN FLUID CO2 Arita T; Beuermann S; Buback M; Vana P Gottingen,Georg-August-Universitat RAFT polymerisations of styrene in liquid carbon dioxide were carried out at 80C and 300 bar using cumyl dithiobenzoate as the controlling agent in the concentration range 0.0035 to 0.021 mol/L. The polymerisation rates were retarded, depending on the concentration of added RAFT agent, with no significant difference between the RAFT polymerisation performed in liquid carbon dioxide and in toluene. Full chain length distributions were analysed with respect to peak molec.wts., indicating the successful control of radical polymerisation in liquid carbon dioxide. A characterisation of the peak widths indicated a minor inÁuence of liquid carbon dioxide on the addition reaction of macroradicals on the dithiobenzoate group. 29 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.920168 Item 10 Macromolecules 37, No.12, 15th June 2004, p.4580-9 GRAFTING OF MALEIC ANHYDRIDE ONTO ISOTACTIC POLYPROPYLENE IN THE PRESENCE OF SUPERCRITICAL CARBON DIOXIDE AS A SOLVENT AND SWELLING FLUID Galia A; De Gregorio R; Spadaro G; Scialdone O; Filardo G Palermo,University Grafting of maleic anhydride(MA) onto isotactic PP(iPP) was carried out by thermal decomposition of dicumyl peroxide(DCP) using supercritical carbon dioxide (scCO2) as a solvent and swelling Áuid. As long as the initial concentration of anhydride dissolved in scCO2 was higher than 1% w/w, the grafting occurred without signiÀcant molec.wt. modiÀcation of the polymer and, with proper selection of the operative conditions, a grafting level higher than 0.5% w/w with respect to the polymer mass was obtained. The amount of grafted MA was determined by FTIR spectroscopy and polymer degradation was monitored by dynamic mechanical tests in the melt state. The effect of MA and DCP concentration, of scCO2 density and of the reaction time on the grafting yield and on the melt Áow behaviour was studied. MA homopolymerisation during the grafting was indicated by the FTIR spectra. The maleated iPP synthesised was an effective compatibilising agent in the preparation of iPP/nylon-6 blends. 42 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; ITALY; WESTERN EUROPE

Accession no.920303

© Copyright 2005 Rapra Technology Limited

Item 11 ANTEC 2003. Proceedings of the 61st SPE Annual Conference held Nashville, Tn., 4th-8th May 2003. BrookÀeld, Ct., SPE, 2003, Volume 1-Processing Session M16-Interface and Compatibilization, p.2271-5, CD-ROM, 012 EFFECTS OF SUPERCRITICAL CO2 ON THE INTERFACIAL REACTION OF MALEIC ANHYDRIDE FUNCTIONALIZED POLYETHYLENE AND POLYAMIDE-6 Xue A; Tzoganakis C Waterloo,University (SPE) Blends of maleic anhydride-functionalised polyethylene and polyamide-6 (PA-6) were prepared by reactive extrusion using a co-rotating twin-screw extruder, with injections of 1-4 wt% carbon dioxide. Nonreactive low density polyethylene was added to some blends to reduced the maleic anhydride (MA) concentration. The degree of interfacial reaction was determined by measuring the amount of unreacted MA by Fourier transform infrared spectroscopy. The MA conversion increased with increasing carbon dioxide concentration. This was attributed to interfacial reactions between the two melt phases. It is proposed that dissolution of carbon dioxide into the polymer melt increased the free volume, which enhanced segmental chain mobility and promoted reorientation of the chain conÀguration, so facilitating contact of reactive functional groups. The inÁuence of carbon dioxide on the MA conversion was less pronounced with increasing PA-6 content in the blend. At high PA-6 concentrations (70%), MA conversions as high as 80% were achieved without the use of carbon dioxide. This was attributed to the development of a crosslinked interfacial region, or to the saturation of copolymers at the interface. 19 refs. CANADA

Accession no.919057 Item 12 Asian Plastics News July-Aug.2004, p.13-4 NEW TECHNOLOGIES FROM JAPAN Japanese Àrms have been working on processes to improve the surface Ànish of plastics parts and obviate the need for coating. Munekata employs supercritical CO2 in a process to improve the surface Ànish of moulded products. Supercritical CO2 is also being used in microcellular foam extrusion. For parts that have been coated, various recycling technologies are available to enable the reuse of plastics. Idemitsu TechnoÀne has developed a system to recycle plated parts by employing a magnetic force to remove metals from recycled plastics after it has been finely powdered. Nanotechnology is another active research area in Japan. Unitika has applied nanotechnology to realise a biodegradable polylactic acid compound with mechanical properties superior to PS, PP and ABS. JAPAN

Accession no.917826

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References and Abstracts

Item 13 Polymer Materials Science and Engineering 20, No.2, March 2004, p.65-8 Chinese STUDY OF POLYPROPYLENE DEGRADATION IN SUPERCRITICAL WATER Wang Jun; Shen Mei-qing; Gong Yan-ling; Ma Pei-sheng Tianjin,University The degradation of PP in supercritical water was studied with particular reference to the inÁuence of conditions such as temperature, pressure, reaction time and ratio of water to PP. The results obtained are discussed in relation to the development of guidelines for degradation of PP and other waste plastics materials in supercritical water. 8 refs. CHINA

Accession no.918212 Item 14 Polymer Materials Science and Engineering 20, No.2, March 2004, p.155-7 Chinese INVESTIGATION OF SORPTION AND DESORPTION OF SUPERCRITICAL CARBON DIOXIDE INTO POLYSTYRENE Chen Cun-she; Xu Hui; Li Xiao-juan Beijing,University of Technology & Business The interaction of supercritical carbon dioxide with PS was investigated systematically. PS Àlms of 0.67 mm thickness were treated with carbon dioxide at pressures between 15 MPa and 30 MPa, at temperatures between 40 and 80C and for soaking times between 6 and 10 h. During carbon dioxide sorption, the formerly transparent PS samples became opaque. The gravimetric desorption data were kinetically evaluated, assuming Fickian diffusion. The sorbed amount of carbon dioxide ranged from 9.7% (80C, 15 MPa) to 13.5% (40C, 25 MPa). The desorption diffusivities decreased with decreasing concentrations of carbon dioxide inside the polymer. 7 refs. CHINA

Accession no.918236 Item 15 Journal of Materials Chemistry 14, No.11, 7th June 2004, p.1663-78 MATERIALS PROCESSING IN SUPERCRITICAL CARBON DIOXIDE: SURFACTANTS, POLYMERS AND BIOMATERIALS Woods H M; Silva M M C G; Nouvel C; Shakesheff K M; Howdle S M Nottingham,University Supercritical carbon dioxide (scCO2) is a unique solvent with a wide range of interesting properties. Recent advances in the use of scCO2 in materials synthesis and materials processing are reviewed. In particular, the

30

advances made in three major areas are considered. First of all, the design and application of new surfactants for use in scCO2 which enable the production of metal nanoparticles, porous polymers and polymers of high molecular weight with excellent morphology. Secondly, the development of new polymer processing and polymer blend technologies in scCO2 which enable the synthesis of some very complex polymer composites and blends. Finally, the application of scCO2 in the preparation of novel biomedical materials, e.g. biodegradable polymer particles and scaffolds. The examples described highlight the fact that scCO2 allows facile synthesis and processing of materials, leading to new products with properties that would otherwise be very difÀcult to achieve. 180 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.917005 Item 16 Macromolecules 37, No.10, 18th May 2004, p.3564-8 EFFECTS OF PRESSURE AND TEMPERATURE ON THE KINETICS OF L-LACTIDE POLYMERIZATION IN SUPERCRITICAL CHLORODIFLUOROMETHANE Pack J W; Kim S H; Park S Y; Lee Y-W; Kim Y H Korea,Institute of Science & Technology; Seoul,National University The ring-opening polymerisation of L-lactide initiated by stannous 2-ethylhexanoate in the presence or absence of 1-dodecanol in supercritical chlorodiÁuoromethane was studied at a range of pressures and temperatures, and the polymers characterised by GPC (molecular weight, polydispersity). The effects of pressure and temperature on polymerisation kinetics are discussed. 37 refs. KOREA

Accession no.917051 Item 17 Journal of Applied Polymer Science 92, No.4, 15th May 2004, p.2363-8 DEPOLYMERIZATION OF POLY(TRIMETHYLENE TEREPHTHALATE) IN SUPERCRITICAL METHANOL Hao-Hong Zhang; Hong-Wei Xiang; Yong Yang; YuanYuan Xu; Yong-Wang Li Chinese Academy of Sciences The depolymerisation of poly(trimethylene terephthalate) (PTT) was carried out in supercritical methanol in a batch reactor at temperatures between 280 and 340C, at pressures between 2.0 and 14.0 MPa and a reaction time of up to 60 min. The degradation products of PTT were dimethyl terephthalate (DMT) and 1,3-propane diol (PDO). The yields of DMT and PDO increased greatly with increasing temperature and the monomer yields increased with increasing pressure up to 10 MPa and then levelled off at

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References and Abstracts

higher pressures. PTT seemed to completely depolymerise to monomers at 320C after 30 min or more. The Ànal yields of DMT and PDO at 320C and 10.0 MPa with a 10:1 weight ratio of methanol to PTT reached 98.2%. A kinetic model for the simulation of the depolymerisation reaction agreed well with the experimental data. In this model, the scission of one PTT ester linkage by a methanol molecule resulted in the formation of one carboxymethyl group and one hydroxyl group. 29 refs. CHINA

Accession no.917303 Item 18 Macromolecules 37, No.7, 6th April 2004, p.2450-3 ENZYME-CATALYZED RING-OPENING POLYMERIZATION OF EPSILONCAPROLACTONE IN SUPERCRITICAL CARBON DIOXIDE Loeker F C; Duxbury C J; Kumar R; Wei Gao; Gross R A; Howdle S M Nottingham,University; Brooklyn,Polytechnic University The ring-opening polymerisation of epsilon-caprolactone was carried out in supercritical carbon dioxide using an enzyme catalyst (Novozym-435, which is lipase B from Candida antarctica supported on macroporous beads). The molecular weights of the poly(epsilon-caprolactone) obtained were very similar to those obtained using toluene but in supercritical carbon dioxide, the polydispersity of the polymer was lower and the yields were higher. The enzyme catalyst could be cleaned and recycled using supercritical carbon dioxide while still producing a high molecular weight polymer. Thus, it was not necessary to use organic solvents. 34 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; USA; WESTERN EUROPE

Accession no.917368 Item 19 Journal of Cellular Plastics 40, No.3, May 2004, p.229-41 SUPERCRITICAL CO2 PROCESSED POLYSTYRENE NANOCOMPOSITE FOAMS Strauss W; D’Souza N A North Texas,University The preparation of cellular PS nanocomposites containing various amounts of montmorillonite-layered silicate using carbon dioxide supercritical Áuid, as a solvent and blowing agent, is reported. The characterisation of compression moulded laminates based on the foams by scanning electron microscopy, DSC and X-ray diffraction is also reported. The effects of the silicate on foam nucleation, growth and microstructure are assessed and the thermal properties of the nanocomposite foams before and after processing tabulated. 24 refs. (SAMPE 2003, Long Beach,

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California; ANTEC 2003, Nashville, Tennessee, 4-8 May, 2003) USA

Accession no.916790 Item 20 Polymer Science Series B 46, No.3-4, March-April 2004, p.61-5 COPOLYMERIZATION OF PROPYLENE OXIDE AND CARBON DIOXIDE UNDER SUPERCRITICAL CONDITIONS Rakhimov T V; Said-Galiev E E; Vinokur R A; Nikitin L N; Khokhlov A R; Il’in V V; Nysenko Z N; Sakharov A M; Schaumberg K Moscow,Institute of Organoelement Compounds; Moscow,Institute of Organic Chemistry; Roskilde,University The copolymerisation of propylene oxide with supercritical carbon dioxide using zinc adipate as catalyst was investigated at different comonomer ratios. The product poly(propylene carbonate) was characterised by proton NMR (copolymer structure) and GPC (molecular weight), and the effects of carbon dioxide concentration on copolymer yield and polydispersity are discussed. 21 refs. DENMARK; EU; EUROPEAN COMMUNITY; EUROPEAN UNION; RUSSIA; SCANDINAVIA; WESTERN EUROPE; WESTERN EUROPE-GENERAL

Accession no.915631 Item 21 ANTEC 2003. Proceedings of the 61st SPE Annual Conference held Nashville, Tn., 4th-8th May 2003. BrookÀeld, Ct., SPE, 2003, Volume 1-Processing Session T7-Polymerisation Catalysis and Application of New Polymers, p.1794-8, CD-ROM, 012 KINETIC STUDY OF THE POLYMERIZATION OF METHYL METHACRYLATE UNDER SUPERCRITICAL FLUID CO2 Lu S; Zhang Z; Nawaby A V; Day M Canada,National Research Council (SPE) High pressure differential scanning calorimetry was used to study the kinetics of the in-situ polymerisation of methyl methacrylate using supercritical carbon dioxide as solvent and benzoyl peroxide as initiator. The steady state polymerisation obeyed Àrst-order reaction kinetics, with rates similar to those observed for polymerisation in air, but the molecular weight 34% was higher. The polymerisation kinetics increased and the induction time decreased with increasing initiator concentration. 14 refs. CANADA

Accession no.915676

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References and Abstracts

Item 22 ANTEC 2003. Proceedings of the 61st SPE Annual Conference held Nashville, Tn., 4th-8th May 2003. BrookÀeld, Ct., SPE, 2003, Volume 1-Processing Session W7-Thermoplastic Foams Applications Part I, p.1812-6, CD-ROM, 012 EFFECT OF MONTMORILLONITE ON FORMATION OF POLYSTYRENE FOAMS USING SUPERCRITICAL CO2 Strauss W; Ranade A; D’Souza N A; Reidy R F; Paceley M North Texas,University (SPE) Styrene monomer, benzoyl peroxide initiator and various concentrations of montmorillonite clay were mixed and heated to initiate in-situ polymerisation. The nanocomposites were compression moulded into sheets of 1.1 mm thickness, which were immersed in liquid carbon dioxide at temperatures in the range 60-85 C at pressures of 7.6-12.0 MPa. After soaking for a set time, the pressure was reduced to atmospheric and the samples cooled at a rate of 1 C/min to room temperature. Rapid carbon dioxide absorption rates were observed, compared with polystyrene, and foams were successfully prepared at temperatures in the range 75-85 C, at pressures of 8-12 MPa. The key process parameters were temperature and depressurisation rate. The cell morphology was strongly dependent upon the clay concentration and dispersion, and preferred orientation was observed round the foam cells. 24 refs. USA

Accession no.915679 Item 23 Journal of Applied Polymer Science 92, No.3, 5th May 2004, p.2008-12 EFFECT OF SUPERCRITICAL CARBON DIOXIDE DYEING CONDITIONS ON THE CHEMICAL AND MORPHOLOGICAL CHANGES OF POLY(ETHYLENE TEREPHTHALATE) FIBERS Hou A; Xie K; Dai J Shanghai,Donghua University The effects of supercritical carbon dioxide dyeing conditions at various temperatures on the chemical and morphological properties of poly(ethylene terephthalate) Àbres were investigated using FTIR, x-ray diffraction, DSC and SEM. The results are discussed in terms of changes in crystal size, melting temperature, crystallinity and surface morphology. 14 refs. CHINA

Accession no.914028

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Item 24 Polyurethanes Expo 2003. Proceedings of a conference held Orlando, Florida, 1st-3rd Oct.2003. Arlington, VA, Alliance for the Polyurethanes Industry, 2003, p.61-6, 28 cm, 012 SUPERCRITICAL OR SUBCRITICAL CO2 ASSISTED WATER BLOWN SPRAY FOAMS Ohnuma Y; Mori J Achilles Corp. (American Plastics Council; Alliance for the Polyurethanes Industry) In Japan, spray foams occupy about 40 % of the rigid PU (PUR) foam market. HCFC-141b used as a blowing agent in this segment is scheduled to be phased out by the end of 2003. Potential substitutes include HFC-245fa, HCF-365mfc and water. The Ministry of Economy, Trade & Industry commenced research on recovery and processing technology of CFCs from thermal insulations for building in 2001. The bank of CFCs in existing rigid PUR foams has been estimated at 29,000 to 36,000 tonnes; there is greater interest in all water or hydrocarbon blown foams. Japanese spray foams are mostly used in the building envelope area where thermal conductivity is not the most critical requirement, so water is considered to be the preferred blowing agent. All water blown PUR foams suffer from poor dimensional stability and poor adhesion to substrates besides high thermal conductivity. Rigid polyisocyanurate (PIR) spray foams using aromatic polyester polyol are widely used in Japan. In this case, if water is used, B-component degradation occurs in a short period. An attempt is made to solve these difÀculties using supercritical or subcritical CO2. With some equipment modification, proprietary water blown spray systems are developed. Adding 1.5% of CO2, isotropic cells are obtained which lead to dimensionally stable foams at the density comparable to HCFC-141b blown foams. Not only is a conventional foam system developed, but also an aromatic polyester polyol-based Áame-retardant foam system in which water is added as a separate stream. These foams can be processed as well as HCFC-141b blown foams and good adhesion is shown even at low temperature. 4 refs. JAPAN

Accession no.914048 Item 25 Materials World 12, No.7, July 2004, p.9-10 ROSTI MEDICAL PLASTICS ANNOUNCES CUTTING EDGE POLYMER ENGINEERING Wilkes S Hard-Plas is a unique polymer hardening process developed by Rosti that looks set to take on products that are traditionally manufactured from metals in a wide variety of Àelds. It is the medical area that will probably be the Àrst to beneÀt from the process, as disposable polymer scalpels hardened using the technique would overcome

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References and Abstracts

problems of possible contamination faced by multipleuse stainless steel scalpels. The process itself is carried out within a pressure vessel that can withstand pressures exceeding 20 bar and temperatures above 120C. The HardPlas process can achieve a surface hardness of at least 7 Mohs or 178 Brinell, equivalent to quartz. Rosti Medical Plastics EUROPEAN COMMUNITY; EUROPEAN UNION; NETHERLANDS; WESTERN EUROPE

Accession no.914369 Item 26 ANTEC 2003. Proceedings of the 61st SPE Annual Conference held Nashville, Tn., 4th-8th May 2003. BrookÀeld, Ct., SPE, 2003, Volume 1-Processing Session W5-Recent Advances in Polymer Structure, Properties and Morphology, p.1610-4, CD-ROM, 012 PROCESSING OF INTRACTABLE POLYMERS USING HIGH-PRESSURE CARBON DIOXIDE Garcia-Leiner M; Lesser A J Massachusetts,University (SPE) To facilitate the processing of polymers with high melt viscosities such as Áuorinated ethylene-propylene copolymer, polytetrafluoroethylene and syndiotactic polystyrene, the feed section of a single screw extruder was modiÀed so that the polymer could interact with carbon dioxide (CO2) under conditions close to or in the supercritical regime prior to extrusion. It was shown that cell nucleation was controlled by the diffusion rate of CO2 in the polymer melt, so that the provision of a saturation time prior to extrusion facilitated foaming. Cell nucleation was also enhanced by operating with the die temperature close to the polymer melting point. Increasing the saturation pressure gave higher cell densities and lower average cell sizes. The enhanced processability was attributed to a plasticisation effect and to a hydrostatic contribution. 23 refs. USA

Accession no.914651 Item 27 Macromolecular Bioscience 4, No.3, 15th March 2004, p.340-5 RING-OPENING POLYMERIZATION OF LACTIDE AND PREPARATION OF ITS MICROSPHERE IN SUPERCRITICAL FLUIDS Pack J W; Kim S H; Park S Y; Lee Y-W; Kim Y H Korea,Institute of Science & Technology; Seoul,National University The ring-opening polymerisation of lactide initiated by stannous octoate was carried out in supercritical chlorodiÁuoromethane at various reaction conditions and reactant concentrations. Polylactide microspheres were prepared by using a continuous supercritical antisolvent process. Molecular weights and MWDs were determined

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using GPC. Characterisation was also undertaken using proton NMR and SEM. 20 refs. KOREA

Accession no.912715 Item 28 Colloid and Polymer Science 282, No.6, April 2004, p.569-74 PRODUCTION OF POLY(METHYL METHACRYLATE) PARTICLES BY DISPERSION POLYMERIZATION WITH MERCAPTOPROPYL TERMINATED POLY(DIMETHYLSILOXANE) STABILIZER IN SUPERCRITICAL CARBON DIOXIDE Fujii S; Minami H; Okubo M Kobe,University PMMA particles were produced by dispersion polymerisation of methyl methacrylate in the presence of mercaptopropyl-terminated polydimethylsiloxane(MPPDMS) in supercritical carbon dioxide with AIBN initiator at about 30 MPa for 24 h at 65C. The particle diameter could be controlled in a size range of submicron to micron by varying MP-PDMS concentration. The MP-PDMS was shown to work not only as a chain transfer agent but also as a colloidal stabiliser. 26 refs. JAPAN

Accession no.912886 Item 29 International Polymer Processing 19, No.1, March 2004, p.77-86 DEVELOPMENT OF A HYBRID SOLIDMICROCELLULAR CO-INJECTION MOLDING PROCESS Turng L-S; Kharbas H Wisconsin-Madison,University The development of a hybrid solid-microcellular coinjection moulding process, which employs a modiÀed two-colour injection moulding machine equipped with an interfacial platen and a supercritical Áuid unit for co-injection moulding, is reported. The production of coinjection moulded PS parts having a microcellular core encapsulated by a solid skin layer is demonstrated and the effects of process conditions and core-skin volume ratios on penetration and morphology of the core are examined. The cell structure and morphology of the parts, as determined by scanning electron microscopy, are compared with microcellular injection moulded PS parts and the potential beneÀts of the process are discussed. 24 refs. USA

Accession no.911353

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References and Abstracts

Item 30 ANTEC 2003. Proceedings of the 61st SPE Annual Conference held Nashville, Tn., 4th-8th May 2003. BrookÀeld, Ct., SPE, 2003, Volume 1-Processing Session T34-Shear Rheology, p.986-90, CD-ROM, 012 RHEOLOGICAL CHANGES IN CO2 IMPREGNATED POLYSTYRENE REINFORCED WITH NANOCLAYS Wingert M J; Han X; Zeng C; Li H; Lee L J; Tomasko D L; Koelling K W Ohio,State University (SPE)

Item 32 ANTEC 2003. Proceedings of the 61st SPE Annual Conference held Nashville, Tn., 4th-8th May 2003. BrookÀeld, Ct., SPE, 2003, Volume 1-Processing Session W22-Microcellular Molding, p.691-5, CDROM, 012 MICROCELLULAR NANOCOMPOSITE INJECTION MOLDING PROCESS Yuan M; Turng L-S; Spindler R; CaulÀeld D; Hunt C Wisconsin-Madison,University; Kaysun Corp.; US,Dept.of Agriculture,Forest Products Laboratory (SPE)

The combined effects of montmorillonite and carbon dioxide additions on the melt rheology of polystyrene (PS) was studied using an extrusion slit die rheometer. In the absence of carbon dioxide, the nanocomposite viscosity increased with increasing clay content. However, the melt viscosity of PS containing carbon dioxide decreased with increasing clay content. It was considered that this may be due to the adsorption of carbon dioxide onto the clay surface, so lubricating the Áow and creating a unique particle layering structure. 21 refs.

Tensile and impact test bars of several polyamides and polyamide-clay nanocomposites were prepared by microcellular injection moulding using nitrogen as the supercritical Áuid. The presence of the supercritical Áuid enhanced the clay exfoliation and dispersion during moulding. Compared with the corresponding microcellular polyamides, the microcellular nanocomposites exhibited superior mechanical properties, cell structures and cell distributions. 4 refs.

USA

Accession no.910803

USA

Accession no.911397 Item 31 ANTEC 2003. Proceedings of the 61st SPE Annual Conference held Nashville, Tn., 4th-8th May 2003. BrookÀeld, Ct., SPE, 2003, Volume 1-Processing Session W22-Microcellular Molding, p.686-90, CDROM, 012 MICROCELLULAR INJECTION MOLDING Turng L-S Wisconsin-Madison,University (SPE) In the microcellular injection moulding process, supercritical nitrogen or carbon dioxide is introduced into the polymer melt in the machine barrel. The gas and polymer phases separate during moulding to form microcells. The beneÀts include lower operating temperatures and pressures, the ability to mould thin walls, reduced cycle times and improved dimensional stability. Samples of a variety of polymers and Àller systems were prepared by microcellular injection moulding using nitrogen gas and a range of processing parameters. The samples were characterised by microstructural studies and by measurements of mechanical properties. The cell size decreased with increasing supercritical gas content, injection speed and melt plastication pressure. The cell size was signiÀcantly reduced by the presence of exfoliated nanoclay. The microcellular structure generally resulted in reductions in tensile, impact and weld line strength. 10 refs. USA

Accession no.910802

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Item 33 ACS Polymeric Materials: Science and Engineering. Spring Meeting 2003. Volume 88. Proceedings of a conference held New Orleans, La., 23rd-27th March 2003. Washington, D.C., ACS,Div.of Polymeric Materials Science & Engineering, 2003, p.92-3, CD-ROM, 012 POLYMER-CLAY NANOCOMPOSITES PREPARED IN SUPERCRITICAL CARBON DIOXIDE Garcia-Leiner M; Lesser A J Massachusetts,University (ACS,Div.of Polymeric Materials Science & Engng.) The preparation of nanocomposites based on either HDPE or polytrimethylene terephthalate and modiÀed or unmodified montmorillonite nanoparticles in the presence of supercritical carbon dioxide is described. The effects of the clay nanoparticles on the morphology and crystallisation of the polymers and on the foaming process are discussed and the inÁuence of supercritical carbon dioxide on melt intercalation is assessed. 10 refs. USA

Accession no.909399 Item 34 Polymer Preprints. Volume 44. Number 1. March 2003. Papers presented at the ACS meeting held New Orleans,Lo., 23rd-27th March 2003. Washington, DC, ACS, Div.of Polymer Chemistry, 2003, p.1216-7, 28CM, 012 DEGRADATION OF PET UNDER SUPERCRITICAL METHANOL

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References and Abstracts

Hanfu Wang; Xiaogang Zhao; Xincai Liu; Yubin Zheng; Zhongwen Wu; Yunchun Zhou Jilin,University; Changchun,Institute of Applied Chemistry A method for degradation of polyethylene terephthalate, and recovery of its constituent parts, using degradation/ depolymerisation under supercritical methanol is described. Recovery of ethylene glycol and dimethyl terephthalate approached 95 percent, under the correct operating conditions of the reactor. Polymers and liquids were characterised by fourier transform infrared spectroscopy and gas chromatography. 5 refs CHINA

Accession no.908541 Item 35 Polymer Preprints. Volume 44. Number 1. March 2003. Papers presented at the ACS meeting held New Orleans,Lo., 23rd-27th March 2003. Washington, DC, ACS, Div.of Polymer Chemistry, 2003, p.1218-9, 28CM, 012 DEGRADATION OF PBT UNDER SUPERCRITICAL METHANOL Hanfu Wang; Yubin Zheng; Zhongwen Wu; Yunchun Zhou Jilin,University; Changchun,Institute of Applied Chemistry A method for degradation of polybutylene terephthalate, using degradation/depolymerisation under supercritical methanol is described. Recovery of a blend of 1,4-butanyldiol and dimethyl terephthalate as a fluid, and dimethyl terephthalate as a solid, approached 100 percent under the correct operating conditions of the reactor. Polymers and liquids were characterised by fourier transform infrared spectroscopy and gas chromatography. 2 refs CHINA

Item 37 Polymer Degradation and Stability 83, No.3, 2004, p.389-93 STUDIES ON THE DECOMPOSITION BEHAVIOR OF NYLON-66 IN SUPERCRITICAL WATER Meng L; Zhang Y; Huang Y; Shibata M; Yosomiya R Harbin,Institute of Technology; Chiba,Institute of Technology Polyamide-6,6 was decomposed in supercritical water and the decomposition products analysed by gas chromatography and mass spectroscopy. The effects of reaction conditions on reaction rate and product yield were examined and the decomposition of polyamide-6,6 in the presence of adipic acid studied. Addition of adipic acid was found to result in an increase in the decomposition rate. 14 refs. CHINA; JAPAN

Accession no.909009 Item 38 Polymer Degradation and Stability 83, No.3, 2004, p.481-5 DECOMPOSITION REACTIONS OF PLASTIC MODEL COMPOUNDS IN SUB- AND SUPERCRITICAL WATER Shibasaki Y; Kamimori T; Kadokawa J-I; Hatano B; Tagaya H Yamagata,University Model compounds of PEEK and PEK having ether linkages, such as dibenzyl ether, dinaphthylether, diphenyl ether, 1,4-diphenoxybenzene and p-phenoxyphenol, were decomposed in subcritical water and supercritical water and the optimum conditions required for decomposition to monomeric compounds investigated. 9 refs. JAPAN

Accession no.909022

Accession no.908542 Item 36 Journal of Polymer Science: Polymer Chemistry Edition 42, No.3, 1st Feb.2004, p.416-31 UNIFORM POLYMER IN SYNTHETIC POLYMER CHEMISTRY Hatada K; Kitayama T; Ute K; Nishiura T Fukui,University of Technology

Item 39 Biomaterials 25, No.13, 2004, p.2611-7 GENERATION OF POROUS MICROCELLULAR 85/15 POLYLACTIDE-CO-GLYCOLIDE FOAMS FOR BIOMEDICAL APPLICATIONS Singh L; Kumar V; Ratner B D Washington,University

The preparation of uniform polymers, polymers composed of molecules uniform with regard to molecular weight and constitution, typically by a combination of living polymerisation and supercritical Áuid separation, and their applications are reviewed. Examples discussed include the study of complex formation between isotactic and syndiotactic poly(methyl methacrylate)s using GPC and NMR. 44 refs.

Porous lactide-glycolide copolymer foams were produced by the pressure quench method using supercritical carbon dioxide as the blowing agent. The rate of carbon dioxide uptake and carbon dioxide equilibrium concentration in the copolymer at different processing conditions were studied by performing sorption experiments. The effects of saturation pressure and temperature on average cell size and relative density of the resulting foams were also studied. 17 refs.

JAPAN

USA

Accession no.908825

Accession no.906946

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References and Abstracts

Item 40 Journal of Materials Science. Materials in Medicine 15, No,2, Feb.2004, p.123-8 LASER STEREOLITHOGRAPHY AND SUPERCRITICAL FLUID PROCESSING FOR CUSTOM-DESIGNED IMPLANT FABRICATION Popov V K; Evseev A V; Ivanov A L; Roginski V V; Volozhin A I; Howdle S M Russian Academy of Sciences; Nottingham,University Details are given of the laser photo polymerisation of a liquid mixture of polyfunctional acrylic monomer, photoinitiator and hydroxyapatite. Pure polymeric and composite materials were fabricated by laser stereolithography based on images derived from 3-D computer modelling. The materials were treated with supercritical carbon dioxide to remove toxic residues and to improve interconnectivity microporosity. Samples were implanted to study living tissue response and processes of osteointegration and osteoinduction. 20 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; RUSSIA; UK; WESTERN EUROPE

Accession no.906934 Item 41 Cellular Polymers 23, No.1, 2004, p.25-37 MICROCELLULAR FOAMING WITH SUPERCRITICAL CARBON DIOXIDE IN INJECTION MOULDING Goodship V; Stewart R L; Hansell R; Ogur E O; Smith G F Warwick,University Commercial systems for microcellular injection moulding are reviewed. The design considerations for nozzle systems for microcellular foaming with supercritical carbon dioxide in injection moulding of polystyrene were investigated. The results are discussed in terms of the effects of pressure drop, weight reduction and injection speed, and recommendations for design modiÀcations are made. 13 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.906826 Item 42 European Plastics News 31, No.2, Feb.2004, p.16-8 FOAM ADVANTAGE Smith C Trexel launched its MuCell microcellular foam moulding technology in 1997 and is gradually building a worldwide network of licensees. Polytec Reisselmann is among the most recent European Àrms to take on the technology, which it is using to manufacture non-visible structural interior trim parts for the Porsche Cayenne and VW Tuareg vehicles. Trexel’s process is based on development work carried out at MIT during the early 1990s exploring supercritical

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Áuids. Under the right circumstances, a relatively uniform microcellular closed-cell structure can be created. It is this structure that Trexel claims sets its MuCell technology apart from alternative internal gas technologies. Sulzer Chemtech’s Optifoam foam injection moulding process is based on technology originally developed at IKV. Sulzer holds exclusive rights to use this technology and plans to market it as a licence-free alternative to the Trexel MuCell system. Demag Ergotech has reached an agreement with Trexel that allows it to supply its Ergocell technology hardware with a discounted Trexel licence. TREXEL INC.; SULZER CHEMTECH AG; DEMAG ERGOTECH GMBH WORLD

Accession no.906319 Item 43 Patent Number: US 6642330 B2 20031104 SUPERCRITICAL FLUID PRESSURE SENSITIVE ADHESIVE POLYMERS AND THEIR PREPARATION McGinniss V D; Vijayendran B R; Spahr K B; Shibata K; Yamamoto T Nitto Denko Corp. Pressure sensitive adhesive (PSA) polymers, especially low Tg, high tack, non-polar and polar polymers useful in formulating PSA, can be solubilised or dispersed in a supercritical Áuid (SCF), such as liquid CO2 or supercritical CO2, using an organic cosolvent, such as toluene. PSA polymers can be polymerised in SCF Áuids to make unique adhesive products. Inclusion of a Áuorinated reactant in the SCF polymerisation process yields a PSA with improved resistance to mineral oil. USA

Accession no.906285 Item 44 Macromolecular Symposia No.204, 2003, p.141-9 EFFECT OF SUPERCRITICAL CO2 ON BULK HYDROGENATION OF NITRILE BUTADIENE RUBBER CATALYZED BY RHCL(PPH3)3 Li G; Pan Q; Rempel G L; Ng F T T Waterloo,University The results are reported of a study of the influence of supercritical carbon dioxide on the bulk hydrogenation of nitrile rubber catalysed with RhCl(PPh3)3. The effects of various parameters, such as reaction time, reaction temperature, hydrogen pressure, catalyst loading and film thickness, on the process are examined. A method for measuring the degree of dissolution or apparent solubility of the catalyst in supercritical carbon dioxide is also reported. 6 refs. (IUPAC 10th International Symposium on Macromolecule-Metal Complexes, Moscow, 18th-23rd May, 2003) CANADA

Accession no.906232

© Copyright 2005 Rapra Technology Limited

References and Abstracts

Item 45 Rubber Chemistry and Technology 76, No.4, Sept.-Oct.2003, p.957-68 DEVULCANIZATION OF SULFUR-CURED ISOPRENE RUBBER IN SUPERCRITICAL CARBON DIOXIDE Kojima M; Ogawa K; Mizoshima H; Tosaka M; Kohjiya S; Ikeda Y Toyo Tire & Rubber Co.Ltd.; Kyoto,University; Kyoto,Institute of Technology The effectiveness of supercritical carbon dioxide as a swelling solvent in the devulcanisation of unfilled polyisoprene vulcanisates with different crosslink densities was evaluated. Devulcanisation was carried out at different temperatures for a period of 60 min. in the presence of various devulcanising agents. The effects of cure time and curing agent on devulcanisation were examined and the chemical structure of the devulcanised rubber analysed by NMR spectroscopy. The degradation of the main chains due to devulcanisation was also examined. 27 refs. JAPAN

Accession no.906201 Item 46 Polymer 44, No.13, 2003, p.3627-32 THIN FLUOROPOLYMER FILMS AND NANOPARTICLE COATINGS FROM THE RAPID EXPANSION OF SUPERCRITICAL CARBON DIOXIDE SOLUTIONS WITH ELECTROSTATIC COLLECTION Fulton J L; Deverman G S; Yonker C R; Grate J W; De Young J; McClain J B PaciÀc Northwest National Laboratory; Micell Technologies The application of nanometer thick Áuoropolymer Àlms onto metal and semiconductor substrates is described. Nanometer-sized polymer particles were generated by homogeneous nucleation during the rapid expansion of supercritical Áuid solutions. Charged nanoparticles were collected on a solid surface forming uniform coatings with thicknesses from tens of nanometers to several micrometers thick. Supercritical carbon dioxide solutions of three different Áuoropolymers were used to generate different types of coatings. 18 refs. USA

Accession no.905933 Item 47 Journal of Polymer Science: Polymer Physics Edition 42, No.2, 15th Jan.2004, p.280-5 EFFECT OF SUPERCRITICAL CARBON DIOXIDE ON THE CRYSTALLIZATION AND MELTING BEHAVIOR OF LINEAR BISPHENOL A POLYCARBONATE Xia Liao; Jin Wang; Gang Li; Jiasong He

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Beijing,State Key Laboratory of Engineering Plastic The crystallisation and melting behaviour of bisphenol A polycarbonate treated with supercritical carbon dioxide for various times at a range of temperatures and pressures was investigated using DSC and wide-angle x-ray diffraction. The effects of the various processing conditions on the crystallisation temperature and the multiple melting behaviour are discussed. 28 refs. CHINA

Accession no.905893 Item 48 Industrial and Engineering Chemistry Research 42, No.25, 10th Dec.2003, p.6431-56 REVIEW OF CO2 APPLICATIONS IN THE PROCESSING OF POLYMERS Tomasko D L; Li H; Liu D; Han X; Wingert M J; Lee L J; Koelling K W Ohio,State University The use of supercritical carbon dioxide as a processing solvent for the physical processing of polymeric materials is reviewed. Fundamental properties of carbon dioxide/polymer systems are discussed with an emphasis on available data and measurement techniques, the development of theory or models for a particular property, and an evaluation of the current state of understanding for that property. Applications such as impregnation, particle formation, foaming, blending and injection moulding are described. 319 refs. USA

Accession no.904409 Item 49 Journal of Polymer Science: Polymer Chemistry Edition 42, No.1, 1st Jan.2004, p.173-85 SYNTHESIS OF HYDROPHILIC POLYMERS IN SUPERCRITICAL CARBON DIOXIDE IN THE PRESENCE OF A SILOXANEBASED MACROMONOMER SURFACTANT: HETEROGENEOUS POLYMERIZATION OF 1-VINYL-2 PYRROLIDONE Galia A; Giaconia A; Iaia V; Filardo G Palermo,University The free radical, particle forming polymerisation of vinyl pyrrolidone in supercritical carbon dioxide in the presence of a reactive polysiloxane surfactant was studied. The reaction was initiated by the thermal decomposition of AIBN. The phase behaviour of the mixture was studied by subjecting the mixture in a high-pressure cell to a progression of stepwise increases in temperature to record the pressure temperature proÀle. The polymers were characterised by their solubility, yields determined gravimetrically and particle size determined by SEM. The polymerisation was followed at various concentrations of the surfactant, then at various concentration of AIBN

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References and Abstracts

initiator, monomer and at different reaction mixture densities. The Hildebrand parameter of the Áuid phase suggests that vinyl pyrrolidone acts as a cosolvent for the polysiloxane chains. Analysis of the kinetics suggested that, for this system, a nucleation mechanism different to that proposed for pure dispersion polymerisation processes was involved. 33 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; ITALY; WESTERN EUROPE

Accession no.904133 Item 50 Journal of Materials Chemistry 13, No.11, Nov.2003, p.2838-44 THE PREPARATION OF NOVEL NANOSTRUCTURED POLYMER BLENDS OF ULTRA HIGH MOLECULAR WEIGHT POLYETHYLENE WITH POLYMETHACRYLATES USING SUPERCRITICAL CARBON DIOXIDE Busby A J; Zhang J; Naylor A; Roberts C J; Davies M C; Tendler S J B; Howdle S M Nottingham,University Several methacrylates were polymerised in an ultrahigh molec.wt. PE matrix using supercritical carbon dioxide and the inÁuence of side chain length on the loading of the methacrylate phase and the morphology of the resulting polymer blends investigated. It was found that the methacrylates were located in nanoscalar phase separated domains within the PE and that these blends could not be fabricated in the absence of the supercritical carbon dioxide. 35 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.901742 Item 51 Polymer Preprints. Volume 44. Number 1. March 2003. Papers presented at the ACS meeting held New Orleans, La., 23rd-27th March 2003. Washington, D.C., ACS,Division of Polymer Chemistry, 2003, p.744-5, 28cm, 012 SOLID STATE POLYMERIZATION OF POLYBISPHENOL A CARBONATE FACILITATED BY SUPERCRITICAL CARBON DIOXIDE Shi C; Gross S M; DeSimone J M; Roberts G W; Kiserow D J North Carolina,State University; Micell Technologies (ACS,Div.of Polymer Chemistry) Details are given of the reaction kinetics of the solidstate polymerisation of polycarbonate with supercritical carbon dioxide as the sweep fluid. Reaction rate constants and phenol diffusivity in the polymer were determined and compared with results obtained for solid-state polymerisation with nitrogen as the sweep gas. The controlling reaction mechanism under different

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polymerisation conditions was determined by comparing the activation energies for chemical reaction and phenol diffusion. 9 refs. USA

Accession no.901299 Item 52 Polymer Preprints. Volume 44. Number 1. March 2003. Papers presented at the ACS meeting held New Orleans, La., 23rd-27th March 2003. Washington, D.C., ACS,Division of Polymer Chemistry, 2003, p.738-9, 28cm, 012 CHEMICAL RECYCLING OF POLYCARBONATES WITH (SUPERCRITICAL) AMMONIA Mormann W; Spitzer D Siegen,Universitat (ACS,Div.of Polymer Chemistry) The behaviour of aliphatic and aromatic polycarbonates towards liquid and supercritical ammonia was investigated. The use of ammonolysis for the chemical recycling of bisphenol-A polycarbonate-containing composites such as compact disks or car windows is discussed. 5 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.901296 Item 53 Macromolecules 36, No.19, 23rd Sept.2003, p.6967-9 SUPERCRITICAL CARBON DIOXIDEMEDIATED INTERCALATION OF PEO IN CLAY Qian Zhao; Samulski E T North Carolina,University A model system of polyethylene oxide (PEO) and sodium montmorillonite was utilised to provide unambiguous evidence for the supercritical carbon dioxide (scCO2) mediated intercalation of the polymer into silicate nanolayers. X-ray diffraction, differential scanning calorimetry and thermogravimetric analysis were used to examine the model system, and the swelling of PEO in scCO2 indicated the strong plasticising effect of the CO2, indicating an enthalpically driven intercalation mechanism similar to that found during melt intercalation. 26 refs. USA

Accession no.901148 Item 54 Colloid and Polymer Science 281, No.10, Oct.2003, p964-72 PRODUCTION OF POLYACRYLONITRILE PARTICLES BY PRECIPITATION POLYMERIZATION IN SUPERCRITICAL CARBON DIOXIDE Okubo M; Fujii S; Maenaka H; Minami H

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References and Abstracts

Kobe,University Polyacrylonitrile particles were produced by precipitation polymerisation of acrylonitrile in supercritical carbon dioxide. The effects of initiation rate of the polymerisation and acrylonitrile concentration on the conversion, the Áuidity of powder, the degree of coagulation, the viscosityaverage molecular weight and the crystallinity were examined in detail. 41 refs. JAPAN

Accession no.900163 Item 55 Journal of Applied Polymer Science 90, No.8, 21st Nov.2003, p.2040-4 SUPERCRITICAL CO2-ASSISTED SYNTHESIS OF POLY(ACRYLIC ACID)/NYLON1212 BLEND Chang Y; Xu Q; Liu M; Wang Y; Zhao Q Zhengzhou,University Blends of polyacrylic acid and polyamide-12,12 were prepared by the infusion of acrylic acid into and radical polymerisation within the polyamide-12,12 using supercritical carbon dioxide as a substrate-swelling agent and monomer/initiator carrier and characterised by DSC, FTIR spectroscopy and scanning electron microscopy. The sorption of carbon dioxide into the polyamide-12,12 and effects of impregnation conditions on the preparation of the blends investigated. 24 refs.

Item 57 Macromolecules 36, No.16, 12th Aug.2003, p.5908-11 SUSPENSION POLYMERIZATION OF LLACTIDE IN SUPERCRITICAL CARBON DIOXIDE IN THE PRESENCE OF A TRIBLOCK COPOLYMER STABILIZER Bratton D; Brown M; Howdle S M Nottingham,University; Smith & Nephew Details are given of the preparation of a well-deÀned Áuorinated triblock copolymer surfactant for suspension polymerisation of polylactide in supercritical carbon dioxide. Data concerning the ether-caprolactone copolymer and their interaction with polylactide particles in suspension polymerisation are discussed. Molecular structures and morphological properties were determined. 27 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.898508 Item 58 Journal of Applied Polymer Science 90, No.4, 24th Oct.2003, p.1113-6 PREPARATION OF CONDUCTING COMPOSITES OF POLYPYRROLE USING SUPERCRITICAL CARBON DIOXIDE Abbett K F; Teja A S; Kowalik J; Tolbert L Georgia,Institute of Technology

CHINA

Accession no.899792 Item 56 Modern Plastics International 33, No.11, Nov.2003, p.18 NEW WAY TO RECYCLE AUTO PLASTICS A group of seven industrial Àrms led by the Fraunhofer Institute for Chemical Technology has developed an economical and safer way to recycle PE fuel tanks from end-of-life vehicles. Over the course of their working lives, the tanks absorb up to 5% of their weight in gasoline or diesel. The research group is studying the use of supercritical carbon dioxide to separate fuel from plastic, it is brieÁy reported. The shredded fuel tanks are placed in pressurised vessels and diffused with CO2 gas. At a speciÀc pressure and temperature, the gas acts as a highly efÀcient solvent, extracting the fuel that has inÀltrated the plastic. FRAUNHOFER-INSTITUT FUER CHEMISCHE TECHNOLOGIE EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.898687

Pyrrole was polymerised in several host polymers (PCTFE, crosslinked PDMS, PMMA and porous crosslinked PS) using supercritical carbon dioxide as the transport medium and reaction medium for in-situ polymerisation and the morphology and electrical conductivity of the resulting composites determined. It was found that conductive composites were formed using PMMA and porous crosslinked PS as host polymers, the level of pyrrole polymerised on the surface or in the pores of the host polymer being sufÀcient to produce the interconnected conducting polymer networks. 17 refs. USA

Accession no.898131 Item 59 Macromolecules 36, No.13, 1st July 2003, p.4779-85 DISPERSION POLYMERIZATION OF MMA IN SUPERCOOLED CARBON DIOXIDE IN THE PRESENCE OF COPOLYMERS OF PERFLUOROOCTYLETHYLENE METHACRYLATE AND POLY(PROPYLENE GLYCOL) METHACRYLATE Lunhan Ding; Olesik S V Ohio,State University Radical copolymerisation was used to prepare a series of random copolymer dispersants based on perfluorooctylethylene methacrylate and propylene

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References and Abstracts

glycol methacrylate. These dispersants were then used for the dispersion polymerisation of methyl methacrylate in supercritical carbon dioxide. Yield and morphology of the resulting polymethyl methacrylate was shown to have a high dependence on composition of the dispersant The effects on the polymerisation process of varying dispersant and monomer concentrations, and the reaction pressure were also examined. Polymers were characterised using scanning electron microscopy, nuclear magnetic resonance spectroscopy, dynamic light scattering and high performance liquid chromatography. 25 refs. USA

Accession no.897575 Item 60 European Polymer Journal 39, No.9, Sept.2003, p.1785-90 THE POLYMERISATION OF FUNCTIONALISED METHACRYLATE MONOMERS IN SUPERCRITICAL CARBON DIOXIDE Giles M R; GrifÀths R M T; Irvine D J; Howdle S M Nottingham,University Isobornyl methacrylate and poly(ethylene glycol)methacrylate were homopolymerised in supercritical carbon dioxide and copolymerised with methyl methacrylate using, as stabiliser systems, poly(dimethyl siloxane) monomethylacrylate and Krytox 157FSL. The effects of initiator (AIBN) concentration and copolymer composition on polymer and copolymer properties, such as solubility, were examined and the performance of the stabilisers compared. 24 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.896214 Item 61 Polymer 44, No.18, 2003, p.5449-54 SUPERCRITICAL CARBON DIOXIDE-ASSISTED SYNTHESIS OF POLY(ACRYLIC ACID)/NYLON6 AND POLYSTYRENE/NYLON6 BLENDS Qun Xu; Yuning Chang; Jinling He; Buxing Han; Yukun Liu Zhengzhou,University; Chinese Academy of Sciences Poly(acrylic acid)/nylon 6 and PS/nylon 6 blends were prepared by the infusion of acrylic acid or styrene into, and radical polymerisation within, solid nylon 6 using supercritical carbon dioxide as a carrier. The content of the incorporated polymers could be controlled by adjusting the reaction conditions. The poly(acrylic acid)/nylon 6 blend had better thermal stability than the original nylon 6. Supercritical carbon dioxide-induced crystallisation was found in carbon dioxide-treated nylon 6 and blend samples. 25 refs. CHINA

Accession no.895482

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Item 62 ACS Polymeric Materials: Science and Engineering. Fall Meeting 2002. Volume 87. Proceedings of a conference held Boston, Ma., 18th-22nd Aug. 2002. Washington, D.C., ACS,Div.of Polymeric Materials Science & Engng., 2002, p.409-10, CD-ROM, 012 TOTALLY “DRY” MICROLITHOGRAPHY IN CARBON DIOXIDE Flowers D; Hoggan E; Carbonell R G; DeSimone J M North Carolina,University; North Carolina,State University (ACS,Div.of Polymeric Materials Science & Engng.) It is proposed that the use of carbon dioxide for the manufacture of integrated circuits would reduce the environmental, wetting and image collapse problems associated with current solvents, whilst acting as a good solvent for the highly Áuorinated polymers proposed for 157 nm photolithography. Liquid carbon dioxide solutions of a random copolymer of perÁuorooctylmethacrylate and tetrahydropyranyl methacrylate (a 193 nm resist system) were used to spin-coat wafers, using ionic and non-ionic photoacid generators (PAG). It is shown that CO2 was able to replace organic and aqueous solvents at each step of the microlithography process. When used in conjunction with an ionic PAG, the system was able to produce images which were developed and stripped in CO2. 5 refs. USA

Accession no.895291 Item 63 Advanced Materials 15, No.13, 4th July 2003, p.1049-59 POROUS MATERIALS AND SUPERCRITICAL FLUIDS Cooper A I Liverpool,University Porous materials are used in a wide variety of applications, including catalysis, chemical separation and tissue engineering. The synthesis and processing of these materials is frequently solvent intensive. In addition to reducing organic solvent emissions, supercritical Áuids (SCFs) offer a number of speciÀc physical, chemical and toxicological advantages as alternative solvents for the production of functional porous materials. The review shows that there is number of speciÀc beneÀts that can be derived from the use of supercritical Áuids for the synthesis and modiÀcation of porous materials. SCFs are useful for the production of microcellular foams, both by expansion and by using crystallisation or anti-solvent phase separation routes. In the case of biocomposite foams, the introduction of toxic solvent residues into the Ànal product can be avoided. The potential of reducing organic solvent usage in the production of porous materials and composites is offered. This is particularly important for processes that currently use large volumes of organic solvents. SCF routes to porous materials that exploit more than one of these speciÀc advantages are likely to be

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References and Abstracts

proÀtable subjects for future research. 126 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.895234 Item 64 Blowing Agents and Foaming Processes 2003. Proceedings of a conference held Munich, Germany, 19th-20th May 2003. Shawbury, Rapra Technology Ltd., 2003, Paper 11, p.101-25, 29 cm, 012 NEW DEVELOPMENTS IN MUCELL MARKETS Traut H Trexel (Rapra Technology Ltd.) The latest developments and commercial applications of the MuCell microcellular foam injection moulding process are presented. In particular, advancements in the MuCell screw design combined with the simple ability to upgrade a standard electric or hydraulic injection moulding machine into a fully capable MuCell moulding machine are described. The MuCell process has been adopted as a core plastics manufacturing technology to achieve higher productivity weight reduction, quality improvement and cost savings. The microcellular foam injection moulding process results in plastic components that are lighter, Áatter, straighter and more dimensionally stable at extreme operating temperatures compared to conventionally moulded parts. The MuCell process can be applied to a wide variety of Àlled and unÀlled materials, including many high temperature engineering resins and thermoplastic elastomers (TPEs). Today there are MuCell products in various markets, including automotive, business equipment, electric/electronic, consumer and medical industries. The MuCell process uses supercritical Áuids (SCF) of inert gases, typically nitrogen or carbon dioxide, to evenly distributed and uniformly sized microscopic cells throughout a polymer. In injection moulding the microcellular foam process enhances product design, improves processing efÀciency and reduces costs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.895001 Item 65 Polymer Composites 24, No.4, Aug.2003, p.545-54 EVALUATING THE MECHANICAL PERFORMANCE OF SUPERCRITICAL CO2 FABRICATED POLYAMIDE 6,6/PMMA, FIBER REINFORCED COMPOSITES Caskey T C; Lesser A J; McCarthy T J Massachusetts,University The mechanical properties of a polyamide-6,6 Àbre/PMMA composite made by a novel supercritical carbon dioxide assisted process under compressive force were investigated.

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Tests were carried out to determine the Áexural and tensile properties of the composites and an analysis was made of the evolution of damage and energy dissipation using a combination of cyclic loading and optical microscopy of post-stressed composite cross-sections. The relationship between the structure and properties of the composites was also analysed to provide a better understanding of the overall performance of the composites. 16 refs. USA

Accession no.894131 Item 66 Macromolecules 36, No.9, 6th May 2003, p.3380-5 QUANTIFYING PLASTICIZATION AND MELTING BEHAVIOR OF POLY(VINYLIDENE FLUORIDE) IN SUPERCRITICAL CARBON DIOXIDE UTILIZING A LINEAR VARIABLE DIFFERENTIAL TRANSFORMER Shenoy S L; Fujiwara T; Wynne K J Virginia,Commonwealth University The plasticisation and melting behaviour of PVDF in supercritical carbon dioxide were studied by measuring linear dilation as a function of temperature (75-130C) and pressure (138-670 bar) using a linear variable differential transformer. In constant temperature experiments at 75 and 99C, the carbon dioxide density or solvent quality determined the degree of swelling. At lower pressures, the rate of change of dilation with pressure increased rapidly up to 414 bar and then attenuated. At 117 and 130C, the rate of change of dilation with pressure was almost linear. Reasons for the higher swelling of PVDF above 100C were discussed. PVDF swelling was measured as a function of temperature at constant pressure. With increasing pressure, the melting temperature decreased to a minimum of 135C at 483 bar. Above 483 bar, hydrostatic effects predominated over plasticisation and the melting temperature increased. 54 refs. USA

Accession no.893374 Item 67 Polymer 44, No.14, June 2003, p.3803-9 HOMO AND COPOLYMERISATION OF 2(DIMETHYLAMINO)ETHYL METHACRYLATE IN SUPERCRITICAL CARBON DIOXIDE Wenxin Wang; Giles M R; Bratton D; Irvine D J; Armes S P; Weaver J V W; Howdle S M Nottingham,University; Uniqema; Sussex,University The free-radical dispersion homopolymerisation of 2-(dimethylamino)ethyl methacrylate(DMA) and copolymerisation of DMA with methyl methacrylate(MMA) in supercritical carbon dioxide were studied. The polymerisations were performed in the presence of two commercially-available stabilisers, poly(dimethylsiloxane)

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References and Abstracts

monomethacrylate macromonomer and the carboxylic acid-terminated perÁuoropolyether (Krytox 157FSL). Dry, Àne powdered polymer product was produced for the copolymer under optimised conditions, but only aggregated solid was formed for homo poly(DMA). The effect of reaction time, stabiliser, copolymer composition and reaction pressure on the yield, molec.wt. and morphology of the copolymers was investigated. 31 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.893235 Item 68 Patent Number: US 6590053 B2 20030708 SUPERCRITICAL FLUID PRESSURE SENSITIVE ADHESIVE POLYMERS AND THEIR PREPARATION McGinniss V D; Vijayendran B R; Spahr K B; Shibata K; Yamamoto T Nitto Denko Corp. Pressure sensitive adhesive (PSA) polymers, especially low Tg, high tack, non-polar and polar polymers, can be solubilised or dispersed in a supercritical Áuid, such as liquid carbon dioxide or supercritical carbon dioxide, using an organic cosolvent, such as toluene. The polymers can be polymerized in supercritical Áuids to make unique adhesive products. Inclusion of a Áuorinated reactant in the polymerisation process yields a pressure-sensitive adhesive with improved resistance to mineral oil. USA

Accession no.892878 Item 69 Polymer Engineering and Science 43, No.6, June 2003, p.1261-75 EXTRUSION OF POLYSTYRENE NANOCOMPOSITE FOAMS WITH SUPERCRITICAL CARBON DIOXIDE Han X; Zeng C; Lee L J; Koelling K W; Tomasko D L Ohio,State University Intercalated and exfoliated PS-nanoclay composites were prepared by mechanical blending and in situ polymerisation. The composites were foamed by using carbon dioxide as the foaming agent in an extrusion foaming process. Foam structures were measured. 59 refs. USA

Accession no.891650 Item 70 Journal of Applied Polymer Science 89, No.3, 18th July 2003, p.742-52 FORMATION OF MICROCAPSULES OF MEDICINES BY THE RAPID EXPANSION OF A SUPERCRITICAL SOLUTION WITH A NONSOLVENT

42

Matsuyama K; Mishima K; Hayashi K I; Ishikawa H; Matsuyama H; Harada T Fukuoka,University; Kyoto Institute of Technology; Mitsubishi Gas Chemical Co.Inc. The rapid expansion from a supercritical solution with a non-solvent(RESS-N) was used to produce polymeric microcapsules of medicines such as p-acetamidophenol, acetylsalicylic acid, 1,3-dimethylxanthine, Áavone and 3-hydroxyÁavone without agglomeration. The cosolvent ethanol was much less toxic than most organic solvents and no surfactant was required. The solubilities of the polymers (polyethylene glycol(PEG), PMMA, ethylcellulose and PEG-polypropylene glycol-PEG copolymer) increased signiÀcantly with addition of a small amount of a lower alcohol. The microcapsules had a globular form and a fairly monodispersed particle size distribution. The average particle diameter and standard deviation of the particle diameter were 14.6 micrometres and 0.41. The particle size distribution of the microcapsules could be controlled by changes in the polymer concentration. It changed very little with the pre-expansion pressure, temperature, injection Áow rate, injection distance and polymer molec.wt. The feed compositions were more effective than other factors for controlling the particle size. 44 refs. JAPAN

Accession no.891295 Item 71 Journal of Polymer Science: Polymer Physics Edition 41, No.12, 15th June 2003, p.1375-83 DRAWING OF ULTRAHIGH MOLECULAR WEIGHT POLYETHYLENE FIBERS IN THE PRESENCE OF SUPERCRITICAL CARBON DIOXIDE Garcia-Leiner M; Song J; Lesser A J Amherst,Massachusetts University; US,Army Soldier Systems Command The in situ drawing behaviour and the physical and mechanical properties of ultrahigh molecular weight polyethylene Àbres drawn uniaxially in supercritical carbon dioxide are compared to those observed for the process carried out in air. SigniÀcant differences in thermal and mechanical properties were observed, and the results of DSC and wide-angle x-ray scattering studies are discussed in terms of the crystallinity of the Àbres. 23 refs. USA

Accession no.889949 Item 72 Journal of Polymer Engineering 23, No.1, Jan.-Feb.2003, p.1-22 RHEOLOGICAL PROPERTIES OF POLYSTYRENE/SUPERCRITICAL CO2 SOLUTIONS FROM AN EXTRUSION SLIT DIE Xue A; Tzoganakis C Waterloo,University

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References and Abstracts

Recent advances in the use of supercritical CO2 (ScCo2) in polymer processing (i.e. injection moulding and extrusion) have increased the need for rheological data of polymer/ ScCO2) solutions at high pressures. A slit die with a sudden contraction is used to investigate the entrance drop as well as the shear and extensional viscosities of a PS melt and of a PS/scCO2 solution. Dissolution of CO2 into the PS melt is shown to reduce its entrance pressure drop as well as its shear and extensional viscosities. The entrance pressure drop of PS and PS/CO2 is found to be a strong (exponential) function of pressure. The entrance pressure drop as a function of wall shear stress can be Àtted with a master curve for all experiments at different temperature, pressure and CO2 concentrations. Shear viscosities of PS as well as PS/CO2 are described using the model and the Doolittle equation and different free volume models are compared. 24 refs. CANADA

Accession no.889376 Item 73 ISFR 2002. Proceedings of a conference held Ostend, Belgium, 8th-11th Sept.2002. Brussels, Belgium, Vrije University, 2002, Paper A39, pp.4, CD-ROM, 012 DECOMPOSITION REACTIONS OF PLASTICS AND THEIR MODEL COMPOUNDS IN SUB- AND SUPERCRITICAL WATER Tagaya H; Shibasaki Y; Kato C; Kadokawa J; Hatano B Yamagata,University (Brussels,Free University; Japan,Research Assn.for Feedstock Recycling of Plastics) Plastics such as xylene resin, epoxy resin and polyetheretherketone resin were decomposed into their monomers such as phenol and cresols by the thermal treatment of them in sub- and supercritical water by using 10ml tubing bomb reactor. The addition of basic compounds such as Na2CO3 was effective on the reaction. In the reaction of xylene resin, the total yield of identiÀed products reached near 40% in the reaction at 703K for 5 h. The reactions of model compounds containing methylene, ether or carbonyl bonds suggested the chemical participation of water on the decomposition reaction of them including the scission of bonds between aromatic polymer units. 10 refs. JAPAN

Eindhoven,University of Technology (Brussels,Free University; Japan,Research Assn.for Feedstock Recycling of Plastics) This study reports a new route for the recycling of consumer electronic plastics. Electronic plastics are either thermoplastic, containing low amounts of additives or thermo-set, normally containing high amounts of additives e.g. heavy metals. Upgrading experiments have shown that thermoplastic electronic parts, like ABS casings, can be recycled, although mechanical properties have degraded because of ageing. It is possible to improve these properties by extruding the recyclates together with certain silanes. For the thermo-set resins a depolymerisation/ extraction route is proposed, which makes molecular recycling possible. This depolymerisation/extraction process is based on the use of supercritical CO2 as extraction medium, which makes separation of wastes and pure monomers recovery technical, economical and environmental feasible. 3 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; NETHERLANDS; WESTERN EUROPE

Accession no.889103 Item 75 Journal of Polymer Science: Polymer Physics Edition 41, No.11, 1st June 2003, p.1143-56 EFFECT OF SUPERCRITICAL CARBON DIOXIDE ON THE DIFFUSION COEFFICIENT OF PHENOL IN POLY(BISPHENOL A CARBONATE Shi C; Roberts G W; Kiserow D J North Carolina,State University; US,Army Research OfÀce The diffusion coefÀcient of phenol in poly(bisphenol A carbonate) was measured during solid state polymerisation of the polymer under diffusion-limited conditions to establish the reason for the faster rate of polymerisation in supercritical carbon dioxide. Phenol diffusivities were determined between 135 and 180C in the presence of atmospheric nitrogen and supercritical carbon dioxide as sweep Áuids and diffusion coefÀcients of condensate molecules calculated from a proÀle of molec.wt. versus time. 32 refs. USA

Accession no.888592

Accession no.889108 Item 74 ISFR 2002. Proceedings of a conference held Ostend, Belgium, 8th-11th Sept.2002. Brussels, Belgium, Vrije University, 2002, Paper A33, pp.4, CD-ROM, 012 DESIGN AND OPTIMISATION OF A SEPARATION, PURIFICATION AND UPGRADING PROCESS FOR POLYMERS FROM ELECTRONIC AND ELECTRIC EQUIPMENT van Schijndel P P A J; van Kasteren H J M N

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Item 76 Macromolecular Rapid Communications 24, No.7, 7th May 2003, p.457-61 WELL-CONTROLLED BIODEGRADABLE NANOCOMPOSITE FOAMS. FROM MICROCELLULAR TO NANOCELLULAR Fujimoto Y; Ray S S; Okamoto M; Ogami A; Yamada K; Ueda K Toyota Technological Institute; Unitika Ltd. The foaming process of polylactide and polylactide-silicate nanocomposites were conducted using supercritical carbon

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References and Abstracts

dioxide as a foaming agent. The morphological correlation between the dispersed silicate particles with nanometer dimensions in the bulk and the obtained closed-cell structure of the foam is discussed. 9 refs.

Item 79 High Performance Plastics June 2003, p.8 SUPERCRITICAL CARBON DIOXIDE PROCESS

JAPAN

A novel recycling process for some of the most common kinds of polymers has been developed by researchers at North Carolina State University in the USA. This short article provides scant details of the new process, which involves the use of supercritical carbon dioxide combined with ethylene glycol or methanol, which reduces the viscosity of the polymer to be recycled, making it easier to process.

Accession no.888565 Item 77 Chemistry of Materials 15, No.10, 20th May 2003, p.2061-9 STRUCTURAL CONTROL IN POROUS CROSSLINKED POLYMETHACRYLATE MONOLITHS USING SUPERCRITICAL CARBON DIOXIDE AS A PRESSUREADJUSTABLE POROGENIC SOLVENT Hebb A K; Senoo K; Bhat R; Cooper A I Liverpool,University The synthesis of permanently porous, highly crosslinked polymethacrylate resins using supercritical carbon dioxide is described. The pressure-adjustable solvent properties were exploited to Àne-tune the average pore size and surface area of the materials. Pore size distributions were recorded by mercury intrusion porosimetry. Morphologies were examined using SEM. 71 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.888558 Item 78 Macromolecules 36, No.5, 11th March 2003, p.1603-8 HIGHLY CONCENTRATED, INTERCALATED SILICATE NANOCOMPOSITES: SYNTHESIS AND CHARACTERIZATION Zerda A S; Caskey T C; Lesser A J Massachusetts,University Nanocomposites of poly(methyl methacrylate) containing in excess of 20 wt% organically modiÀed montmorillonites were prepared using a custom-made high pressure apparatus. Monomer, radical initiator and clay were added to the apparatus along with supercritical carbon dioxide, which lowered the viscosity of the system, homogeneously distributed the monomer and facilitated clay intercalation. The d spacing of intercalated nanocomposites containing less than 40 wt% clay was commensurate with the dimensions of the fully extended surfactant chains. Larger clay additions decreased the d spacing as the composite volume became saturated with the inorganic material. A model to estimate this transition concentration is given. A 50% increase in modulus was obtained for a 40 wt% clay addition, whilst the glass transition temperature was unchanged. Orientation achieved by subsequent melt processing increased the tensile modulus, as determined by dynamic mechanical thermal analysis, by 220%. 29 refs. USA

Accession no.888394

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NORTH CAROLINA,STATE UNIVERSITY USA

Accession no.888308 Item 80 Polymer Preprints. Volume 43. Number 2. Fall 2002. Papers presented at the ACS Meeting held Boston, Ma., 18th-22nd Aug.2002. Washington, DC, ACS, Div.of Polymer Chemistry, 2002, p.1252-3, 28cm, 012 TREATMENT OF PEEK UNDER SUPERCRITICAL ETHANOL Hanfu Wang; Xincai Liu; Liang Chen; Zhongwen Wu; Yunchun Zhou Jilin,University; Changchun,Institute of Applied Chemistry (ACS,Div.of Polymer Chemistry) The treatment of PEEK under supercritical ethanol was studied and the properties of the treated polymer were examined by techniques such as IR spectroscopy, X-ray diffraction, DSC and rheological measurements. It was shown that supercritical Áuid had an extraction effect on PEEK and that this effect provided evidence for the model of melting-recrystallisation with a double melting peak. 2 refs. CHINA

Accession no.888084 Item 81 Polymer Preprints. Volume 43. Number 2. Fall 2002. Papers presented at the ACS Meeting held Boston, Ma., 18th-22nd Aug.2002. Washington, DC, ACS, Div.of Polymer Chemistry, 2002, p.956, 28cm, 012 SUPERCRITICAL CO2 POST-PLASTICIZATION MORPHOLOGIES OF PVDF AND PVDFCOPOLYMER Fujiwara T; Shenoy S LWvnne K J Virginia,Commonwealth University (ACS,Div.of Polymer Chemistry) Super-critical CO2 has attracted considerable attention in polymer processes such as fractionation and swelling because of its non-toxic, non-corrosive and non-Áammable

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References and Abstracts

properties. Processing behaviour as a function of temperature and pressure has been studied by various methods. However, there are few studies on the postplasticised morphologies. The conformation change of syndiotactic PS after SCCO2 plasticisation by using Xray technique has been reported. Recently, a programme to study plasticisation of semicrystalline polymers as a function of pressure and temperature approaching melting point (Tm) has been initiated. Unique post-plasticised thermal behaviour is described and the morphologies of PVDF and PVDF copolymer, vinylidene Áuorideco-5 mol.% hexafluoropropylene (PVDF-HFP), are investigated. 9 refs. USA

Accession no.887894 Item 82 Plastics and Rubber Weekly 2nd May 2003, p.9 JYCO SEALING USES MUCELL PROCESS FOR AUTOMOTIVE FOAM SEALS Proving that the MuCell microcellular foaming technology is not just for injection moulders, US-based Jyco Sealing Technologies is using the process to manufacture foamed thermoplastic vulcanisate (TPV) weatherstrips for the automotive sector. According to chief executive ofÀcer Sam Jyawook, the foaming process is critical in the production of weather seals because an open-cell structure will not meet the demanding automotive industry standards. The MuCell technique, which uses supercritical Áuids to create the foam structure, has proved to give good control of cell structure, reducing surface porosity and preventing moisture uptake. MuCell developer Trexel now has a commercial TPV foaming process. TPVs are predicted to continue replacing EPDM in weather-seal applications, where they are claimed to provide easier recyclability, colourability and improved design Áexibility. The company claims its process is consistent in highoutput manufacturing processes with a range of material formulations. JYCO SEALING TECHNOLOGIES; TREXELL INC. USA

Accession no.887869 Item 83 Polymer Preprints. Volume 43. Number 2. Fall 2002. Papers presented at the ACS Meeting held Boston, Ma., 18th-22nd Aug.2002. Washington, DC, ACS,Div.of Polymer Chemistry, 2002, p.1338, 28cm, 012 MICROCELLULAR FOAMING OF AMORPHOUS HIGH-TG POLYMER USING CARBON DIOXIDE Wang D; Jin Y; Jiang Z; Wu Z Jilin,University (ACS,Div.of Polymer Chemistry)

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The preparation and SEM characterisation of microcellular foams from high-Tg fluorinated aromatic PEEK are described. These foams, produced using supercritical carbon dioxide, as blowing agent, are closed-cell foams with low dielectric constants and better thermal insulation properties than their matrix. A SEM micrograph of the microcellular polymer is illustrated. 4 refs. CHINA

Accession no.886331 Item 84 Polymer 44, No.8, 2003, p2201-11 CARBOXYLIC ACID END GROUP MODIFICATION OF POLY(BUTYLENE TEREPHTHALATE) IN SUPERCRITICAL FLUIDS de Gooijer J M; Scheltus M; Jansen M A G; Koning C E Eindhoven,University of Technology; DSM Research ModiÀcation of polybutylene terephthalate carboxylic end groups by 1,2-epoxybutane was carried out at different temperatures and pressures in supercritical carbon dioxide, and mixtures of this with an added 10 mol percent of dioxane. Highest modiÀcation was achieved in the mixed solvent at the highest experimental temperature, resulting in much improved hydrolytic stability of the polymer as observed by molecular weight measurements and intrinsic viscosity change with respect to hydrolysis time. An increase in crystallinity was observed, using differential scanning calorimetry, due to the plasticising effect of the mixed solvents. 27 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; NETHERLANDS; WESTERN EUROPE

Accession no.885760 Item 85 Journal of Applied Polymer Science 88, No.9, 31st May 2003, p2189-93 PLASTICISATION OF POLYMERS WITH SUPERCRITICAL CARBON DIOXIDE: EXPERIMENTAL DETERMINATION OF GLASS TRANSITION TEMPERATURES Alessi P; Cortesi A; Kikic I; Vecchione F Trieste,University A method for the study of the plasticisation effect of supercritical carbon dioxide on polymers, including polymethyl methacrylate, polystyrene and polycarbonate, and its effect on glass transition temperature was shown to be high-pressure partition chromatography, a modiÀcation to inverse gas chromatography. Experimental results were compared with published Àgures for each polymer, and shown to be in good agreement. 14 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; ITALY; WESTERN EUROPE

Accession no.885711

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References and Abstracts

Item 86 European Polymer Journal 39, No.3, March 2003, p.423-8 MONITORING DISPERSION POLYMERISATIONS OF METHYL METHACRYLATE IN SUPERCRITICAL CARBON DIOXIDE Wang W; GrifÀths R M T; Giles M R; Williams P; Howdle S M Nottingham,University; UK,Health and Safety Laboratory Details are given of the development of power compensation calorimetry equipment to monitor the dispersion polymerisation of methyl methacrylate in supercritical carbon dioxide. The effect of initiator concentration and stabiliser on the reaction was studied and the enthalpy of polymerisation obtained from the apparatus was found to correlate with other reported data. 21 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.884200

Item 89 Polymer Preprints. Volume 43. Number 2. Fall 2002. Papers presented at the ACS Meeting held Boston, Ma., 18th-22nd Aug.2002. Washington, D.C., ACS,Div.of Polymer Chemistry, 2002, p.889, 28cm, 012 POLYMERIZATION OF VINYLIDENE FLUORIDE IN DENSE CARBON DIOXIDE Wojcinski L M; Saraf M K; Charpentier P; DeSimone J M; Roberts G W North Carolina,State University; North Carolina,Chapel Hill University (ACS,Div.of Polymer Chemistry) Vinylidene Áuoride was polymerised via free radical precipitation polymerisation in supercritical carbon dioxide in a continuous stirred tank reactor. The initiator was diethyl peroxydicarbonate. The resulting PVDF was highly porous with a novel bimodal molecular weight distribution which varied with reaction conditions such as monomer concentration, temperature and pressure. No refs. USA

Item 87 Journal of Applied Polymer Science 88, No.5, 2nd May 2003, p.1393-8 MOLECULAR WEIGHT AND SPINNABILITY OF POLYACRYLONITRILE PRODUCED BY PRECIPITATION POLYMERIZATION IN SUPERCRITICAL CO2 Teng X-R Tongji,University Details are given of the precipitation polymerisation of acrylonitrile in supercritical carbon dioxide. The effects of monomer and initiator concentration, total reaction time, temperature and carbon dioxide pressure on polymer molecular weight were investigated. Processability is discussed. 25 refs. CHINA

Accession no.884127 Item 88 Revista de Plasticos Modernos 83, No.550, April 2002, p.409-18 Spanish POLYMERISATION AND SUPERCRITICAL SOLVENTS Trabelsi S; Ajzenberg N; Recasens F Catalunya,Universitat Politecnica The characteristics of supercritical Áuids are examined, and their possible use as solvents in solution, suspension and emulsion polymerisation reactions is discussed. The application of such Áuids in plastics recycling by depolymerisation reactions is also considered. 47 refs.

Accession no.883973 Item 90 Polymer Preprints. Volume 43. Number 2. Fall 2002. Papers presented at the ACS Meeting held Boston, Ma., 18th-22nd Aug.2002. Washington, D.C., ACS,Div.of Polymer Chemistry, 2002, p.888, 28cm, 012 SUPERCRITICAL AND LIQUID CARBON DIOXIDE: POLYMER SWELLING AND EFFECTS ON MELTING BEHAVIOR Wynne K J; Shenoy S; Fujiwara T; Irie S; Woerdeman D; Sebra R; Garach A; McHugh M Virginia,Commonwealth University (ACS,Div.of Polymer Chemistry) A linear variable differential transformer method was used to measure the dilation of polymer samples by supercritical and liquid carbon dioxide. Results obtained with SBS, PS, PMMA and PVDF showed that each polymer had a characteristic pattern of swelling behaviour. The linear dilation for SBS was very low and was complicated by compression. However, “inÁation” of the sample occurred when the pressure was released. The solubility of carbon dioxide in PS was very low, although the glass transition temperature was greatly affected. The solubility of carbon dioxide in PMMA was much greater and the glass transition temperature of PMMA was also sharply lowered by supercritical carbon dioxide. Semicrystalline PVDF showed complex swelling behaviour which was sensitive to temperature. 7 refs. USA

Accession no.883972

EUROPEAN COMMUNITY; EUROPEAN UNION; SPAIN; WESTERN EUROPE

Accession no.884067

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References and Abstracts

Item 91 Polymer Preprints. Volume 43. Number 2. Fall 2002. Papers presented at the ACS Meeting held Boston, Ma., 18th-22nd Aug.2002. Washington, D.C., ACS,Div.of Polymer Chemistry, 2002, p.887, 28cm, 012 PLASTICIZATION AND MELTING BEHAVIOR OF PVDF AND PVDF COPOLYMERS IN SUPERCRITICAL CARBON DIOXIDE Shenoy S L; Fujiwara T; Wynne K J Virginia,Commonwealth University (ACS,Div.of Polymer Chemistry) PVDF and poly(vinylidene fluoride-co-4.9 mol% hexaÁuoropropylene) were plasticised by supercritical carbon dioxide. The degree of plasticisation depended strongly on the temperature and the pressure. The hexaÁuoropropylene groups resulted in a much larger swelling of the copolymer. The melting temperatures of both the homopolymer and the copolymer were lowered by polymer-supercritical carbon dioxide interactions. However, above about 540 bar, there was a modest increase in the melting temperature due to the hydrostatic pressure. Thus, the melting behaviour was a balance between the lowering of the melting temperature due to plasticisation and increasing it due to the hydrostatic pressure. 12 refs. USA

Accession no.883971 Item 92 Journal of Applied Polymer Science 88, No.2, 11th April 2003, p.522-30 SURFACE MODIFICATION OF POLYBUTADIENE FACILITATED BY SUPERCRITICAL CARBON DIOXIDE Ngo T T; McCarney J; Brown J S; Lazzaroni M J; Counts K; Liotta C L; Eckert C A Georgia,Institute of Technology The hydrophilicity of polybutadiene was increased by treating the polymer surface with hydrophilic monomers (such as 3-vinylbenzoic acid and crotonic acid) in the presence of a photoinitiator in a supercritical carbon dioxide environment. The carbon dioxide acted as the swelling agent for the polymer and the transport medium for solutes to diffuse on to the polymer surface. The carbon dioxide pressure had a substantial effect on the partitioning of the solute between the polymer and the Áuid phase and a smaller effect on the diffusivity of the solute onto the polymer surface. Based on these results, the operating conditions of the process could be optimised to obtain the required surface properties. The dimerisation kinetics of carboxylic acids in carbon dioxide solution were examined. This dimerisation behaviour signiÀcantly affected the solubility and diffusivity of the acids in solution. 15 refs.

Item 93 Polymer Preprints, Volume 43. Number 2. Fall 2002. Papers presented at the ACS Meeting held Boston, Ma., 18th-22nd Aug. 2002. Washington, DC, ACS,Div. of Polymer Chemistry, 2002, p.938-9, 28 cm, 012 ELECTROCHEMICAL SYNTHESIS AND CHARACTERIZATION OF CONDUCTING POLYPYRROLE FILMS IN SUPERCRITICAL CARBON DIOXIDE Badlani R N; Mayer J L; Anderson P E; Mabrouk P A Northeastern University (ACS,Div.of Polymer Chemistry) Pyrrole polymers were synthesised by the electrochemical polymerisation of pyrrole in supercritical carbon dioxide on gold disks and indium tin oxide/glass working electrodes. They were characterised by cyclic voltammetry, four-point probe conductivity, scanning electron microscopy and UV vis spectroscopy and found to exhibit relatively high conductivity and distinct surface morphology. 21 refs. USA

Accession no.883668 Item 94 ANTEC 2002. Proceedings of the 60th SPE Annual Technical Conference held San Francisco, Ca., 5th-9th May 2002. BrookÀeld, Ct., SPE, 2002, Paper 611, Session W17-Applied Rheology. Wall Slip, Instabilities and Processing Aids, pp.5, CD-ROM, 012 RHEOLOGY AND EXTRUSION OF CO2 PLASTICIZED ACRYLIC COPOLYMERS Bortner M J; Baird D G Virginia,Polytechnic Institute & State University (SPE) The reduction of the glass transition temperature (Tg) and hence the melt viscosity of poly(acrylonitrile-comethyl acrylate) (10 mol% methyl acrylate) by the addition of carbon dioxide, to facilitate melt spinning, was investigated. Copolymer pellets were saturated with carbon dioxide in a sealed pressure vessel for various time periods. Following depressurisation, dynamic and steady shear measurements were made using a torsional rheometer, and a modiÀed capillary rheometer, pressurised using nitrogen, was used to study both saturated and unsaturated copolymer. Tg was determined by differential scanning calorimetry. A reduction of approximately 40% in melt viscosity was obtained on saturating the copolymer with carbon dioxide, leading to a reduction in processing temperature of up to 20 C. 7 refs. USA

Accession no.883569

USA

Accession no.883780

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References and Abstracts

Item 95 Journal of Polymer Science: Polymer Physics Edition 41, No.4, 15th Feb.2003, p.368-77 PREPARATION AND CHARACTERIZATION OF MICROCELLULAR POLYSTYRENE/ POLYSTYRENE IONOMER BLENDS WITH SUPERCRITICAL CARBON DIOXIDE Jin Wang; Xingguo Cheng; Xuejing Zheng; Mingjun Yuan; Jiasong He Beijing,Institute of Chemistry

Item 97 Polymer Engineering and Science 43, No.1, Jan.2003, p.157-68 EFFECT OF PROCESS CONDITIONS ON THE WELD-LINE STRENGTH AND MICROSTRUCTURE OF MICROCELLULAR INJECTION MOLDED PARTS Lih-Sheng Turng; Kharbas H Wisconsin-Madison,University

Preparation of microcellular PS, lightly sulphonated PS(SPS), zinc-neutralised lightly sulphonated PS(ZnSPS) and blends of PS/SPS and PS/ZnSPS via supercritical carbon dioxide was carried out using the pressure-quench process. Both higher foaming temperature and lower pressure resulted in larger cell sizes, lower cell densities and lower relative density for microcellular ionomers and blends than for microcellular PS. The difference between the various microcellular samples was the change of cell size with the sample composition. The cell size decreased in the sequence from SPS, through PS/SPS blends, PS and PS/ZnSPS blends, to ZnSPS. The diffusivity of carbon dioxide in samples also decreased in the sequence from SPS, through PS/SPS blends, PS and PS/ZnSPS blends, to ZnSPS. For this series of samples with similar structure and identical solubility of carbon dioxide, the varying diffusivity was responsible for the difference of cell sizes. 36 refs.

The way in which the process conditions affected the weldline strength and microstructure of injection-moulded microcellular parts was investigated. Experimental design was used and polycarbonate tensile test specimens were produced for tensile tests and microscopic analysis. Injection moulding trials were performed by systematically adjusting four process parameters, i.e. melt temp., shot size, supercritical Áuid level and injection speed. Conventional solid specimens were also produced for comparison. The TS was measured at the weld line and away from the weld line. The weld-line strength of injection moulded microcellular parts was lower than that of its solid counterparts. It increased with increasing shot size, melt temp. and injection speed and was weakly dependent on the supercritical Áuid level. The microstructures of the moulded specimens at various cross-sections were examined using SEM and optical microscopy in order to study the variation of cell size and density with different process conditions. 21 refs.

CHINA

USA

Accession no.882238

Accession no.881046

Item 96 Industrial and Engineering Chemistry Research 42, No.3, 5th Feb.2003, p.448-55 DISPERSION COPOLYMERIZATION OF VINYL MONOMERS IN SUPERCRITICAL CARBON DIOXIDE Galia A; Muratore A; Filardo G Palermo,University

Item 98 Journal of Applied Polymer Science 87, No.7, 14th Feb.2003, p.116-22 REACTIVE EXTRUSION OF POLYPROPYLENE WITH SUPERCRITICAL CARBON DIOXIDE: FREE RADICAL GRAFTING OF MALEIC ANHYDRIDE Dorscht B M; Tzoganakis C Waterloo,University

An investigation was carried out into the free-radical copolymerisation of methyl methacrylate and N,Ndimethylacrylamide initiated by the thermal decomposition of AIBN in supercritical carbon dioxide in the presence of polysiloxane surfactants. The phase behaviour of the reaction mixture was examined by combining visual observation of the mixture to the recording of the pressure trend inside a Àxed-volume view cell during slow heating and cooling of the reaction mixture. The effects of the nature of the surfactant, feed composition and surfactant concentration on dispersion copolymerisation were studied and the end-use properties of the copolymers evaluated. 24 refs.

Supercritical carbon dioxide was used in a reactive extrusion process for the peroxide-initiated functionalisation of PP with maleic anhydride. The use of supercritical carbon dioxide led to improved free radical grafting of maleic anhydride on to PP when high levels of maleic anhydride were used. There was no evidence of improvement in the homogeneity of the product and melt Áow rate measurements showed a reduction in the degradation of PP during the grafting reaction when low levels of maleic anhydride were used. 26 refs. CANADA

Accession no.880727

EUROPEAN COMMUNITY; EUROPEAN UNION; ITALY; WESTERN EUROPE

Accession no.881794

48

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References and Abstracts

Item 99 Advanced Materials 14, No.24, 17th Dec.2002, p.1802-4 INCORPORATION OF PROTEINS INTO POLYMER MATERIALS BY A NOVEL SUPERCRITICAL FLUID PROCESSING METHOD Watson M S; Whitaker M J; Howdle S M; Shakesheff K M Nottingham,University The preparation of porous tissue engineering poly(D,Llactide) scaffolds containing biologically active material for controlled-release using a combination of solution and supercritical Áuid processing, which permits the accurate dosing of biological agent and provides a very clean route to porous materials, is described. The controlled release of avidin tagged with rhodamine using these scaffolds and retention of biological activity throughout supercritical carbon dioxide reprocessing using the enzyme ribonuclease A are demonstrated. 23 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.880165

viscosity reduction due to addition of supercritical carbon dioxide became less. 22 refs. TAIWAN

Accession no.879404 Item 102 RP Asia 2002: Composites in the global market. Proceedings of a conference held Kuala Lumpur, Malaysia, 5th-6th Sept.2002. Oxford, Elsevier Science Ltd., 2002, Paper 14, p.263-6, 29cm, 012 COMPOSITES WASTE MANAGEMENT Nomaguchi K Japan,Society of Plastics Recycling (Elsevier Science Ltd.) Polymer composites are very durable, but eventually they must Ànish their service life and become “waste”. The author has been studying composite waste management and trying to exchange information among North American, European and Asian regions to Ànd the most efÀcient methods. This paper covers basic ideas on composite waste management and the practical processes which have been developed. 4 refs. JAPAN

Item 100 Polymer Preprints. Volume 42. Number 2. Fall 2001. Papers presented at the ACS meeting held Chicago, Il., 26th-30th Aug.2001. Washington, DC, ACS,Div.of Polymer Chemistry, 2001, p.817, 28cm, 012 POLYMERIZATION OF VINYL CHLORIDE IN SUPERCRITICAL CARBON DIOXIDE Li G; Johnston K P; Zhou H; Venumbaka S R; Cassidy P Texas,University (ACS,Div.of Polymer Chemistry) Details are given of the polymerisation of vinyl chloride in supercritical carbon dioxide using AIBN as initiator. Molecular weight was determined using GPC. 5 refs. USA

Accession no.879641 Item 101 Journal of Polymer Research 9, No.3, 2002, p157-62 STUDY ON THE RHEOLOGICAL BEHAVIOR OF PP/SUPERCRITICAL CARBON DIOXIDE MIXTURE Hung-Yu Lan; Hsieng-Cheng Tseng Taiwan,National University of Science & Technology An injection moulding machine was modiÀed with gas injection port and special screw to measure the rheological behaviour of polypropylene (PP) mixed with supercritical carbon dioxide. A reduction in viscosity of the polymer was expected, compared to the pure PP, but this was found to be greatest at low shear rates. As the shear rate increased,

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Accession no.879311 Item 103 ANTEC 2002. Proceedings of the 60th SPE Annual Technical Conference held San Francisco, Ca., 5th-9th May 2002. BrookÀeld, Ct., SPE, 2002, Paper 487, Session T48Alloys & Blends. Morphology Development, pp.5, CD-ROM, 012 EFFECTS OF SUPERCRITICAL CO2 ON THE DISPERSED PHASE SIZE AND COCONTINUITY OF PS/LDPE BLENDS Xue A; Tzoganakis C Waterloo,University (SPE) Blends of polystyrene and low density polyethylene (LDPE), containing 10-90 vol% LDPE, were prepared using a co-rotating twin-screw extruder, with 4 wt% supercritical carbon dioxide injected into the barrel. Scanning electron microscopy, and gravimetry following selective extraction showed that the CO2 reduced the dispersed phase size, and also reduced the region of cocontinuity, attributed to a reduction in melt viscosity. The morphology at the die following CO2 venting was similar to that of blends was no CO2 addition. In the co-continuous region, very Àne morphologies were observed during the foaming process. 16 refs. CANADA

Accession no.878322

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References and Abstracts

Item 104 ANTEC 2002. Proceedings of the 60th SPE Annual Technical Conference held San Francisco, Ca., 5th-9th May 2002. BrookÀeld, Ct., SPE, 2002, Paper 392, Session T32Engineering Properties and Structure. PolyoleÀns III: Structure and Properties of PolyoleÀns, pp.5, CD-ROM, 012 DRAWING OF UHMWPE FIBERS IN THE PRESENCE OF SUPERCRITICAL CO2 Garcia-Leiner M; Song J; Lesser A J Massachusetts,University; US,Army Soldier Systems Command (SPE) Ultra high molecular weight polyethylene Àbres were drawn in air and in supercritical carbon dioxide (scCO2) over a range of temperatures. The drawing properties in air varied with temperature, whilst in scCO2 they were temperature-independent. Differential scanning calorimetry and wide angle X-ray scattering studies showed that crystallisation of the air-drawn samples occurred in an internally constrained manner which resulted in changes in the thermal behaviour. However, in scCO2, crystals grew without constraint, possibly due to crystal-crystal transformation, allowing the processing temperature to increase up to 110 C. 12 refs. USA

Accession no.876482 Item 105 ANTEC 2002. Proceedings of the 60th SPE Annual Technical Conference held San Francisco, Ca., 5th-9th May 2002. BrookÀeld, Ct., SPE, 2002, Paper 351, Session T25Applied Rheology, Extrusion I, Thermoplastic Materials and Foams. Interactive Presentations, pp.5, CD-ROM, 012 VISCOSITY MEASUREMENTS ON POLYPROPYLENE MIXED WITH SUPERCRITICAL FLUID AT HIGH SHEAR RATES Hung-Yu Lan; Hsieng-Cheng Tseng Taiwan,National University of Science & Technology (SPE) An injection moulding machine with a 36 mm diameter screw was modiÀed by Àtting a carbon dioxide injector port to the barrel and a slit die with pressure transducers in front of the nozzle. Flow rates were determined by measuring screw displacement. Reduction in the viscosity of polypropylene by the introduction of supercritical CO2 was investigated, the viscosity being determined by applying Bagley and Rabinowitsch corrections to the measured pressure and Áow rates. A 30% reduction in viscosity was achieved at low shear rates, and stable values were observed at high shear rates. 21 refs. TAIWAN

Accession no.876441

50

Item 106 Industrial and Engineering Chemistry Research 41, No.24, 27th Nov.2002. p.6049-58 SUPERCRITICAL CO2 BASED PRODUCTION OF MAGNETICALLY RESPONSIVE MICRO- AND NANOPARTICLES FOR DRUG TARGETING Chattopadhyay P; Gupta R B Auburn,University A supercritical antisolvent technique was used to produce magnetically responsive PMMA, lactideglycolide copolymer and Eudragit RS polymer particles via coprecipitation of the polymer with a suspension of magnetite particles in mineral oil and a fatty acid surfactant, using dichloromethane as the solvent. The supercritical antisolvent technique was used to precipitate drug-loaded magnetically responsive polymer particles. Size, morphology and drug-release kinetics of the particles were studied. 33 refs. USA

Accession no.875759 Item 107 Chemistry of Materials 14, No.11, Nov.2002, p.4619-23 COMPOSITES PREPARED BY THE POLYMERIZATION OF STYRENE WITHIN SUPERCRITICAL CARBON DIOXIDESWOLLEN POLYPROPYLENE Zhimin Liu; Zexuan Dong; Buxing Han; Jiaqui Wang; Jun He; Guanying Yang Beijing,Institute of Chemistry The monomer styrene and the initiator AIBN dissolved in supercritical(SC) carbon dioxide were impregnated into SC carbon dioxide-swollen PP matrix at 35C and the monomer was then polymerised within the PP substrates at 70C, resulting in PP/PS composites. The Young’s modulus and TS of the PP were improved signiÀcantly in the presence of PS. TEM, DSC and IR spectroscopy were used to characterise the morphology and microstructure of the composites. The results showed that the PS was more homogeneously dispersed in the blends and its phase size was in the range of nanometers. Some of the PS entangled with PP in the composites. The special microstructures and morphology of the blends resulted in the enhanced mechanical performances of PP/PS composites. 27 refs. CHINA

Accession no.875594 Item 108 European Polymer Journal 39, No.1, Jan.2003, p.151-6 SYNTHESIS OF ELECTRICALLY CONDUCTIVE POLYPYRROLE-POLYSTYRENE COMPOSITES USING SUPERCRITICAL CARBON DIOXIDE. II. EFFECTS OF THE DOPING CONDITIONS

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References and Abstracts

Tang M; Wen T-Y; Du T-B; Chen Y-P Chinese Culture University; Taipei,National Taiwan University A polymer composite was produced by impregnating a pyrrole monomer within a PS substrate in supercritical carbon dioxide followed by soaking the resulting composite in a solution of a metal salt to form an electrically conductive composite. The effects of doping solvent (acetonitrile or water), doping temperature and nature of the oxidants (iron chloride, iron sulphate, iron perchlorate or iron nitrate) on the electrical conductivity of the composites were investigated and the heat stability of the composites determined by thermogravimetry. 18 refs. TAIWAN

Accession no.875416 Item 109 Industrial and Engineering Chemistry Research 41, No.22, 30th Oct.2002, p.5393-400 HYDROTHERMAL DECHLORINATION AND DENITROGENATION OF MUNICIPAL-WASTEPLASTICS-DERIVED FUEL OIL UNDER SUBAND SUPERCRITICAL CONDITIONS Akimoto M; Ninomiya K; Takami S; Ishikawa M; Sato M; Washio K Niigata,University The hydrothermal processing of municipal-waste-plasticsderived fuel oil (kerosene fraction; Cl content = 62 ppm, N content = 1150 ppm) under sub- and supercritical conditions is investigated so as to demonstrate the possible use of water and aqueous solutions of metal salts and hydroxides for the dechlorination and denitrogenation of the fuel oil. The hydrothermal processing is carried out in a small SUS316 stainless steel batch reactor under nitrogen atmosphere. Although the two reactions take place in water, they proceed much more readily under basic conditions, especially in aqueous solutions of alkaline metal hydroxides. That is, the nitrogen content in the product oil decreases to 297 ppm upon processing with water for 15 min at 425 deg.C, whereas it decreases to 49 ppm when 0.10 mol/L NaOH is used instead of water at 375 deg.C. Under these hydrothermal conditions, the chlorine content in the product oil is always nearly 0 ppm. Organic acids such as benzoic acid and phthalic acid in the fuel oil can also be removed. 37 refs.

The degradation kinetics of polycarbonate (poly(bisphenol A carbonate)) in supercritical and subcritical benzene is studied at various temperatures (523-618 K) at 50 atm. The degradation is also investigated in other solvents at 573 K and 50 atm. The time evolution of molecular weight distribution is obtained by gel permeation chromatography and modelled with continuous distribution kinetics to obtain the degradation rate coefÀcients. The activation energy, determined from the temperature dependence of the rate coefÀcient, increases from 16.7 to 20.4 kcal/mol from the subcritical region to the supercritical region of the solvent. The degradation rate coefÀcients at the supercritical conditions are an order higher than the rate coefÀcients at subcritical conditions, indicating enhanced degradation at supercritical conditions. The Arrhenius plot shows a break at the supercritical transition point, while the semilogarithmic plot of rate coefÀcients with the density of the reaction mixture shows a continuous linear variation. 17 refs. INDIA

Accession no.875148 Item 111 Polymer 43, No.25, 2002, p.6653-9 PREPARATION OF CROSS-LINKED MICROPARTICLES OF POLY(GLYCIDYL METHACRYLATE) BY DISPERSION POLYMERIZATION OF GLYCIDYL METHACRYLATE USING A PDMS MACROMONOMER AS STABILIZER IN SUPERCRITICAL CARBON DIOXIDE Wenxin Wang; GrifÀths R M T; Naylor A; Giles M R; Irvine D J; Howdle S M Nottingham,University; Uniqema The dispersion polymerisation of glycidyl methacrylate was carried out using poly(dimethylsiloxane) monomethacrylate macromonomer as the stabiliser in supercritical carbon dioxide. Under optimised conditions, discrete crosslinked polymer particles were produced with high monomer conversion during a very short reaction time of less than 4 h. The reaction pressure and stabiliser concentration affected the morphology of the Ànal product. 18 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.874632

JAPAN

Accession no.875151 Item 110 Industrial and Engineering Chemistry Research 41, No.22, 30th Oct.2002, p.533-40 KINETICS OF DEGRADATION OF POLYCARBONATE IN SUPERCRITICAL AND SUBCRITICAL BENZENE Silvalingam G; Madras G Indian Institute of Science

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Item 112 Macromolecules 35, No.23, 5th Nov.2002, p.8869-77 PREPARATION OF A POLYMETHYL METHACRYLATE/ULTRAHIGH MOLECULAR WEIGHT POLYETHYLENE BLEND USING SUPERCRITICAL CARBON DIOXIDE AND THE IDENTIFICATION OF A THREEPHASE STRUCTURE. AN ATOMIC FORCE MICROSCOPY STUDY Zhang J; Busby A J; Roberts C J; Chen X; Davies M C;

51

References and Abstracts

Tendler S J B; Howdle S M Nottingham,University Supercritical carbon dioxide was used as a processing medium to facilitate impregnation and polymerisation of methyl methacrylate in ultrahigh molecular weight PE. Morphological structures were investigated using tapping mode atomic force microscopy. DSC analysis was also carried out. 37 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.873640 Item 113 Polymer Engineering and Science 42, No.11, Nov.2002, p.2234-45 MEASUREMENT AND PREDICTION OF LDPE/ CO2 SOLUTION VISCOSITY Areerat S; Nagata T; Ohshima M Kyoto,University The melt viscosities of LDPE/supercritical carbon dioxide solutions were measured with a capillary rheometer equipped at a foaming extruder. The viscosity measurements were performed by varying the content of carbon dioxide and temperature. Melt viscosities were measured by measuring the pressure drop and Áow rate of polymer running through the tube. A mathematical model was developed to predict viscosity reduction owing to carbon dioxide dissolution. 34 refs. JAPAN

Accession no.873543 Item 114 Polymer Engineering and Science 42, No.11, Nov.2002, p.2094-106 CONTINUOUS MICROCELLULAR POLYSTYRENE FOAM EXTRUSION WITH SUPERCRITICAL CO2 Han X; Koelling K W; Tomasko D L; Lee L J Ohio,State University The continuous production of PS microcellular foams with supercritical carbon dioxide was achieved on a twostage single-screw extruder. Simulations related to the foaming process were accomplished by modelling the phase equilibria with the Sanchez-Lacombe equations of state and combining the equations of motion, the energy balance, and the Carreau viscosity model to characterise the Áow Àeld and pressure distribution in the die. The position of nucleation in the die was determined from the simulation results via a computational Áuid dynamics code. The effects of carbon dioxide concentration and die pressure were investigated. 48 refs. USA

Accession no.873530

Item 115 Silicones in Coatings IV. Proceedings of a conference held Guildford, UK, 30th-31st May 2002. Teddington, Paint Research Association, 2002, Paper 4, pp.11, 29cm, 012 SUPERCRITICAL FLUIDS AND SILICONES - A POTENTIAL REVOLUTION OF WOOD AND OTHER POROUS MATERIALS - AN UPDATE Johns K; Hay J N Chemical & Polymer; Surrey,University (Paint Research Association) The use of silicone polymers and of supercritical carbon dioxide technology in the coating of various substrates, but particularly of wood, is described. The problems of wood coating are considered and the selection of suitable biocides and water repellents is discussed. The environmental advantages of using supercritical Áuid systems are examined and their use in powder coatings, inverse microemulsions and microporous coatings is described. 36 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.873338 Item 116 Polymer Engineering and Science 42, No.9, Sept.2002, p.1907-18 FOAM PROCESSING AND CELLULAR STRUCTURE OF POLYPROPYLENE/CLAY NANOCOMPOSITES Pham Hoai Nam; Maiti P; Okamoto M; Kotaka T; Nakayama T; Takada M; Ohshima M; Usuki A; Hasegawa N; Okamoto H Toyota Technological Institute; Kyoto,University; Toyota Central R & D Laboratories Inc. PP/clay nanocomposites(PPCNs) were autoclave-foamed in a batch process. Foaming was performed using supercritical carbon dioxide at 10 MPa, within the temp. range 130.6 to 143.4C, i.e. below the m.p. of either PPCNs or maleic anhydride(MA)-modiÀed PP matrix without clay. The foamed PP-MA and PPCN2 (prepared at 130.6C and containing 2 wt % clay) showed closed cell structures with pentagonal and/or hexagonal faces, while foams of PPCN4 and PPCN7.5 (prepared at 143.4C, 4 and 7.5 wt % clay) had spherical cells. SEM conÀrmed that foamed PPCNs had high cell density of 10,000,000 to 100,000,000 cells/mL, cell sizes in the range of 30 to 120 micrometres, cell wall thicknesses of 5 to 15 micrometres and low densities of 0.05 to 0.3 g/mol. TEM observations of the cell structure showed biaxial Áow-induced alignment of clay particles along the cell boundary. The correlation between foam structure and rheological properties of the PPCNs is also discussed. 15 refs. JAPAN

Accession no.873198

52

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References and Abstracts

Item 117 ACS Polymeric Materials: Science and Engineering. Spring Meeting. Volume 84. Proceedings of a conference held San Diego, Ca., 1st-5th April 2001. Washington, D.C., ACS,Div.of Polymeric Materials Science & Engng., 2001, Paper 343, p.625-6, 27cm, 012 SUPERCRITICAL CARBON DIOXIDE INTERACTION WITH POLYMERIC MATERIALS: SORPTION AND DESORPTION DIFFUSION COEFFICIENT Shuely W J; Ince B S US,Research & Technology Directorate; US,Army,Aberdeen Proving Ground (ACS,Div.of Polymeric Materials Science & Engng.) Sorption and desorption diffusion coefÀcient measurements by means of TGA were carried out to characterise the plasticisation of a range of polymers by supercritical carbon dioxide, which is utilised as a cleaning Áuid for sensitive equipment. Polymers tested included PVC, PPO, polycarbonate, PMMA and polydimethylsiloxane. The time required to return to the unplasticised state was estimated using diffusion coefÀcient equations and continuous desorption curve measurements permitted adjustment and correction for extractables and zero-time sorption measurement lag after decompression. 3 refs. USA

Accession no.872806 Item 118 Foams 2002. Proceedings of a conference held Houston, Tx., 22nd-23rd Oct.2002. BrookÀeld, Ct., 2002, Session VII, p.163-8, 27cm, 012 INNOVATIVE FOAMING TECHNOLOGIES Reedy M E Reedy International Corp. (SPE,Thermoplastic Materials & Foams Div.; SPE,South Texas Section) Many new innovative technologies are now being introduced and reintroduced for foamed injection moulding processing. Often called microcellular foaming, the new technologies utilise a number of approaches to achieve Àne cellular structures with double-digit weight and cycle time reductions. The key to the innovative technologies is computerised process control, good tool design including counter pressure, static melt mixing and new chemical blowing agents. These technologies have subtle differences, which are very important for optimum part performance. Technologies include a microcellular injection moulding process using supercritical gas and polymer mixtures, which reduce part weight while creating a swirled surface Ànish. A class A surface is obtained with the use of Textron’s IntelliMould, a process control system that decreases part weight and cycle time while eliminating surface irregularities. In addition, new compact gas counter pressure modules are providing signiÀcantly improved structural foam processing. Processors are also using new tailored static mixers to create highly uniform melt components at constant temperatures.

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New chemical blowing agents (CBAs) are making dramatic strides in achieving reproducible cell distributions and cell size in microcellular foaming. New applications include automotive mouldings, such as foamed bumpers and fascia. CBAs now utilise microencapsulated small particle size components with very narrow distributions to achieve both signiÀcant weight reduction and cycle time improvement. Trials show that these improvements can be achieved on conventional equipment. 11 refs. USA

Accession no.871809 Item 119 162nd ACS Rubber Division Meeting - Fall 2002. Proceedings of a conference held Pittsburgh, Pa., 8th11th Oct. 2002. Akron, Oh., ACS Rubber Division, 2002, Paper 116, pp.17, 28cm, 012 DEVULCANIZATION OF UNFILLED NATURAL RUBBER IN SUPERCRITICAL CARBON DIOXIDE Kojima M; Tosaka M; Kohjiya S; Ikeda Y Kyoto,University; Kyoto,Institute of Technology (ACS,Rubber Div.) Sulphur cured unÀlled NR was devulcanised in supercritical carbon dioxide using diphenyl disulphide, as devulcanising agent, and the product fractionated into sol and gel fractions. The structure and properties of the devulcanised rubber were determined by rheometry, viscometry, swelling measurements, NMR spectroscopy, GPC and DSC. The dependence of devulcanisation on the amount of devulcanising agent, pressure and time was examined and the effect of crosslink distribution in the vulcanisate on devulcanisation evaluated. 20 refs. JAPAN; USA

Accession no.871413 Item 120 Journal of Applied Polymer Science 86, No.9, 28th Nov.2002, p.2338-41 MOLECULAR WEIGHT DISTRIBUTION OF POLYACRYLONITRILE PRODUCED IN SUPERCRITICAL CARBON DIOXIDE Xin-rong Teng; Hui-li Shao; Xue-chao Hu Shanghai,Donghua University An effectively linear molec.wt. calibration curve of PAN was obtained using a copolymer standard with a single broad MWD. The molec.wts. and MWDs of PAN obtained from precipitation polymerisation of acrylonitrile in supercritical carbon dioxide were quantiÀed by the calibration curve. The effects of monomer concentration, initiator concentration, carbon dioxide pressure and total reaction time on the molec.wt. and MWD were studied in detail. 28 refs. CHINA

Accession no.871260

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References and Abstracts

Item 121 Journal of Applied Polymer Science 86, No.9, 28th Nov.2002, p.2272-8 IMPROVEMENT IN THE WATER-ABSORBING PROPERTIES OF SUPERABSORBENT POLYMERS (ACRYLIC ACID-CO-ACRYLAMIDE) IN SUPERCRITICAL CARBON DIOXIDE Li Ma; Le Zhang; Ji-Chu Yang; Xu-Ming Xie Tsinghua,University

homogeneous kinetic model that included chain transfer to polymer predicted the polydispersities reasonably well. This model also predicted a region of inoperability that matched the experimental results. The extended homogeneous model could not, however, account for the bimodal distributions. 26 refs.

Superabsorbent resins prepared from acrylic acid and acrylamide were prepared by UV polymerisation and were treated with supercritical carbon dioxide(SC-CO2). The water-absorbing properties of the treated resins were found to be signiÀcantly improved. The water-absorbing properties of resins treated with SC-CO2 in a pressure range of 10 to 35 MPa and a temp. range of 40 to 60C were studied. The effects of treatment time and depressurising speed of carbon dioxide after treatment were also examined. Different results were found for particles of different sizes, smaller particles being more efÀcient under the same treatment conditions. The samples were tested using DSC. The results showed that the plasticising effect of carbon dioxide reduced the Tg of the polymer and it was suggested that the plasticisation effect might have led to polymer chain redistribution and better Áexibility. Minor changes in the surface morphology of the particles were observed by SEM. The extraction of the unpolymerised monomers by SC-CO2 was also studied. 13 refs.

Item 123 ANTEC 2002. Proceedings of the 60th SPE Annual Technical Conference held San Francisco, Ca., 5th-9th May 2002. BrookÀeld, Ct., SPE, 2002, Paper 235, Session M44Applied Rheology. Experimental And Numerical Flow Modeling, pp.4, CD-ROM, 012 MELT PROCESSING OF POLYMERS USING SUPERCRITICAL FLUIDS Matthews S O; Dhadda K S; Hornsby P R Brunel University (SPE)

USA

Accession no.871097

CHINA

Low density polyethylene, with and without additions of glass beads, was processed using single screw and co-rotating twin-screw extruders Àtted with slit dies carrying pressure transducers and thermocouples for rheometry measurements. Supercritical carbon dioxide injected into the polymer during processing signiÀcantly reduced viscosity, the reduction being greater than theoretical predictions. 8 refs.

Accession no.871251

EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.870783 Item 122 Macromolecules 35, No.21, 8th Oct.2002, p.7976-85 CONTINUOUS PRECIPITATION POLYMERIZATION OF VINYLIDENE FLUORIDE IN SUPERCRITICAL CARBON DIOXIDE: FORMATION OF POLYMERS WITH BIMODAL MOLECULAR WEIGHT DISTRIBUTIONS Saraf M K; Gerard S; Wojcinski L M; Charpentier P A; DeSimone J M; Roberts G W North Carolina,State University; North Carolina,University The polymerisation of vinylidene Áuoride in supercritical carbon dioxide was studied in a continuous stirred tank reactor using diethylperoxydicarbonate as the free radical initiator. The effect of inlet monomer concentration, temp., average residence time and stirring on the polymerisation rate, average molec.wts. and MWD of the PVDF. A homogeneous kinetic model that included inhibition due to chain transfer to monomer predicted the polymerisation rates reasonably well. Imperfect mixing rather than a chemical effect could, however, have caused the apparent inhibition observed at high monomer concentrations. At inlet monomer concentrations greater than about 1.5M, broad and bimodal MWDs were observed. An extended

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Item 124 Polymer Preprints. Volume 41, Number 1. Proceedings of a conference held San Francisco, Ca., March 2000. Washington D.C., ACS,Div.of Polymer Chemistry, 2000, p.14-5, 28cm, 012 SYNTHESIS OF LINEAR POLY(TETRAFLUOROETHYLENE-CO-VINYL ACETATE) IN SUPERCRITICAL CARBON DIOXIDE Lausenberg R D; Shoichet M S Toronto,University (ACS,Div.of Polymer Chemistry) Linear copolymers of tetraÁuoro ethylene and vinyl acetate were prepared in supercritical carbon dioxide solution with different initiator and tetraÁuoroethylene concentrations. The linearity of the polymers was proven by attempted hydrolysis of the vinyl acetate to vinyl alcohol, where only a slight change in molar mass was observed. Causes of this mass change were discussed. Polymers were characterised using gel permeation chromatography, fourier transform infrared and nuclear magnetic resonance analysis, and elemental analysis. 13 refs. CANADA

Accession no.868858

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References and Abstracts

Item 125 Polymer Preprints. Volume 42, Number 1. Spring 2001. Papers presented at the ACS meeting held San Diego, Ca., 1st-5th April 2001. Washington D.C., ACS,Div.of Polymer Chemistry, 2001, p.159-60, 28cm, 012 HYDROSILATION POLYMERIZATIONS WITH DIALLYL MONOMER-BENZENE SOLUTION VS SUPERCRITICAL CARBON DIOXIDE Welsch R; Blanda M T; Venumbaka S R; Cassidy P E; Fitch J W Southwest Texas,State University (ACS,Div.of Polymer Chemistry) Comparison was made of the use of supercritical carbon dioxide (SC CO) or benzene as solvent for the solution polymerisation of a new class of Áuorine and silicone containing polymers. Polymers were prepared from synthesised diallyl Áuorine containg monomers and a dihydrosilane or a siloxane using a platinum complex catalyst. Molecular weights of polymers obtained when using SC CO were equivalent or higher than when benzene was used. Polymers had good thermal stability in both air and argon. Polymers were characterised using infrared and nuclear magnetic resonance spectroscopy, gel permeation chromatography, differential scanning calorimetry and thermogravimetric analysis. 6 refs USA

the carbon-13 NMR method used. 19 refs. CHINA

Accession no.868607 Item 127 Polymer 43, No.20, 2002, p.5511-20 GENERATION OF MICROCELLULAR FOAMS OF PVDF AND ITS BLENDS USING SUPERCRITICAL CARBON DIOXIDE IN A CONTINUOUS PROCESS Siripurapu S; Gay Y J; Royer J R; DeSimone J M; Spontak R J; Khan S A North Carolina,State University Supercritical carbon dioxide was used as a blowing agent to generate microcellular foams of PVDF and its blends with PS or PMMA in a continuous process. Foams of neat PVDF and immiscible blends with PS showed poor cell characteristics but miscible blends of PVDF with PMMA produced foams with greatly improved morphologies. The PVDF/PMMA melt viscosity, decreased markedly with increasing PMMA content and supercritical carbon dioxide concentration. The cell density of microcellular PVDF/PMMA foams increased with increasing PMMA fraction and decreasing foaming temperature. 32 refs. USA

Accession no.868068

Accession no.868798 Item 126 Polymer Journal (Japan) 34, No.7, 2002, p.534-8 STUDY ON THE STEREOREGULARITY OF POLYACRYLONITRILE PRODUCED BY PRECIPITATION POLYMERIZATION IN SUPERCRITICAL CARBON DIOXIDE Xin-Rong Teng; Xue-Chao Hu; Hui-Li Shao Tongji,University; Shanghai,Donghua University The triad and pentad tacticities of PAN obtained by precipitation polymerisation in supercritical carbon dioxide, using AIBN as initiator (referred to as CO2-PAN), were analysed by carbon-13 NMR and IR spectroscopies. The pentad tacticities of CO2-PAN from the intensities of cyano peaks were examined by statistical methods. It was found that CO2-PAN was completely random in stereoregularity and its sequence distributions obeyed Bernoullian statistics. Comparisons were made with the aqueous phase suspension polymerisation of acrylonitrile, using AIBN as initiator (referred to as S-PAN), and aqueous phase precipitation polymerisation of acrylonitrile, using redox-type initiator (R-PAN), and it was found that the isotacticity of CO2-PAN was lower than that of S-PAN and R-PAN, although the three types of PAN were all random in stereoregularity. The cause was probably the different polarities of the solvents used. The relation between IR data and stereoregularity of PAN was also used to calculate the isotactic triad units of CO2-PAN and the result was shown to be in agreement with

© Copyright 2005 Rapra Technology Limited

Item 128 Polymer Preprints. Volume 42. Number 1. Spring 2001. Papers presented at the ACS Meeting held San Diego, Ca., 1st-5th April 2001. Washington, D.C., ACS,Div.of Polymer Chemistry, 2001, p.518-9, 28cm, 012 RING-OPENING METATHESIS POLYMERIZATION OF NORBORNENE IN SUPERCRITICAL CARBON DIOXIDE Xiaochuan Hu; Blanda M T; Venumbaka S R; Cassidy P E Southwest Texas,State University (ACS,Div.of Polymer Chemistry) Ring-opening metathesis polymerisation of norbornene was carried out in supercritical carbon dioxide. The molecular weight, molecular weight distribution and thermal stability of the polynorbornenes synthesised by this method were similar to those of polynorbornenes synthesised in the conventional THF solvent. A high trans structure was obtained in all the polynorbornenes prepared using the Grubbs catalyst and the trans/cis ratio could be adjusted by adding co-solvent (THF and toluene). However, when the Schrock’s catalyst was used, a high cis structure was obtained. Temperature had no effect on the cis/trans ratio of the polymers but affected the molecular weights and their distribution; Pressure had no signiÀcant effect on the microstructure of the polynorbornenes prepared in supercritical carbon dioxide. 9 refs. USA

Accession no.867542

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References and Abstracts

Item 129 ANTEC 2002. Proceedings of the 60th SPE Annual Technical Conference held San Francisco, Ca., 5th-9th May 2002. BrookÀeld, Ct., SPE, 2002, Paper 131, Session M28Injection Moulding Analysis, pp.5, CD-ROM, 012 STUDY OF WELD-LINE STRENGTH AND MICROSTRUCTURE OF INJECTION MOLDED MICROCELLULAR PARTS Kharbas H; Turng L-S; Spindler R; Burhop B Wisconsin-Madison,University; Kaysun Corp. (SPE) The inÁuence of process parameters on the weld line strength and microstructure of polycarbonate processed by microcellular injection moulding was investigated. The mould temperature and the melt back pressure were maintained constant at 71.1 C and 17.2 MPa, respectively. The weld line strength increased with increasing melt temperature, injection speed, and shot size, and also exhibited a weak dependence on the supercritical Áuid level. 5 refs. USA

Accession no.867335 Item 130 Journal of Materials Chemistry 12, No.9, Sept.2002, p.2688-91 SYNTHESIS OF COMPOSITES OF SILICON RUBBER AND POLYSTYRENE USING SUPERCRITICAL CO2 AS A SWELLING AGENT Liu Z; Wang J; Dai X; Han B; Dong Z; Yang G; Zhang X; Xu J Chinese Academy of Sciences The heterogeneous free-radical polymerisation of styrene within supercritical carbon dioxide swollen silicon rubber Àlm is conducted to prepare silicone rubber/PS (SR/PS) polymer blends. The PS content in the blends can be controlled by adjusting the soaking time and the concentration of styrene in the supercritical Áuid. Scanning electron microscopy (SEM) indicates that the PS phase is uniformly distributed in the blends, and the phase size is very small, although the two polymers are very different and incompatible. The mechanical properties of the blends and the average molecular weight of the PS polymerised in the matrix are also measured. The results indicate that the average molecular weight of the PS in the blend depends on the PS content or its phase size. The tensile strength of the blends is higher than that of original SR substrate, and there is a maximum in tensile strength in.vs. PS content. Young’s modulus of the blends increases monotonously with PS content in the blends. 23 refs.

Item 131 Polymer 43, No.19, 2002, p.5363-7 PREPARATION OF NANOMETER DISPERSED POLYPROPYLENE/POLYSTYRENE INTERPENETRATING NETWORK USING SUPERCRITICAL CO2 AS A SWELLING AGENT Dan Li; Zhimin Liu; Buxing Han; Liping Song; Guanying Yang; Tao Jiang Chinese Academy of Sciences Nanometer dispersed polypropylene/polystyrene interpenetrating networks are prepared. These IPNs are then characterised in terms of thermal and mechanical properties, and the features of the IPNs formed are studied. The IPNs are prepared by the radical polymerisation and crosslinking of styrene within supercritical CO2-swollen PP substrates. Styrene, divinyl benzene (crosslinking agent) and benzoyl peroxide (initiator) were impregnated into a polypropylene matrix using supercritical CO2 as a solvent and swelling agent at 35 degree C, then polymerisation and crosslinking were carried out at 120 degree C. The compositions of the IPNs can be controlled by the supercritical CO2 pressure, styrene concentration and divinyl benzene concentration. The impact strength, tensile strength and elongation-at-break of the IPNs increases with the content of polystyrene. 26 refs. CHINA

Accession no.866550 Item 132 Macromolecular Symposia Vol.184, 2002, p.215-28 POLYMERS AND SUPERCRITICAL FLUIDS: OPPORTUNITIES FOR VIBRATIONAL SPECTROSCOPY Kazarian S G London,Imperial College of Science,Technology & Medicine A report is presented on the use of in-situ ATR-IR spectroscopy to study changes in polymers subjected to supercritical Áuids. Experiments are conducted utilising an ATR-IR cell with a diamond crystal accessory to measure the spectra. Application of this technique to study the sorption of high-pressure CO2 into polymers, swelling of polymers in high-pressure CO2, impregnation of polymers from supercritical CO2 solution, CO2-induced polymer melting and PMMA stereocomplex formation and polymers in near-critical water. 42 refs. (14th European Symposium on Polymer Spectroscopy, Dresden, 2nd-5th Sept., 2001, Germany)

CHINA

EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.866646

Accession no.866443

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© Copyright 2005 Rapra Technology Limited

References and Abstracts

Item 133 Advanced Materials and Processes 160, No.6, June 2002, p.19-20 NANOCOMPOSITE DENSE PLASTIC FOAM REPLACES SOLID PLASTIC It is briefly reported that researchers at Ohio State University claim to have developed nanocomposite plastic foam that is strong enough to replace solid plastic in structural applications such as car or airplane panels. To make foam, manufacturers inject gases into hot liquid plastic. The Ohio State researchers added nanometre-size clay particles to the molten plastic, and small bubbles of the injected gas about Àve microns across formed around the nanoparticles, adhering to them. With a foam that contains 5% clay particles, boards were made that are just as strong as typical foam, but two thirds as thick. OHIO,STATE UNIVERSITY USA

Accession no.864095 Item 134 Polymer Preprints. Volume 43, Number 1. Spring 2002. Papers presented at the ACS meeting held Orlando, Fl., 7th-11th April 2002. Washington D.C., ACS,Div.of Polymer Chemistry, 2002, p.744-5, 28cm, 012 EMULSION TEMPLATING USING SUPERCRITICAL FLUID EMULSIONS Butler R; Davies C M; Hopkinson I; Cooper A I Liverpool,University; Cavendish Laboratory (ACS,Div.of Polymer Chemistry) A new technique for using supercritical carbon dioxide, at volume fractions up to 80 percent, as the internal oil phase in emulsion templating during the preparation of porous polymers is described. Polymerisations of acrylamide with methylene bisacrylamide or hydroxyethyl acrylate and methylene bisacrylamide were carried out at different monomer concentrations and carbon dioxide volume fractions to illustrate the technique, and pore sizes were measured using mercury intrusion porosimetry. Polymer area was determined using nitrogen adsorption (BET method) and scanning electron microscopy was used to examine polymer morphology. Confocal microscopy was used to determine cell sizes. The claimed advantage of this method over others for preparation of porous monolithic polymers is the lack of involvement of organic solvents. 8 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.862535

FLUORIDE IN SUPERCRITICAL CARBON DIOXIDE: MOLECULAR WEIGHT DISTRIBUTION Saraf M K; Wojcinski L M; Kennedy K A; Gerard S; Charpentier P A; DeSimone J M; Roberts G W North Carolina,State University An investigation was carried out into the surfactant-free precipitation polymerisation of vinylidene Áuoride in supercritical carbon dioxide using, as polymerisation initiator, diethyl peroxydicarbonate. Polymerisation was carried out in a continuous stirred autoclave at temperatures from 65 to 85C and at pressures between 210 and 305 bar. Molecular weight distributions of the polymers were determined by GPC and the effects of inlet monomer concentration, total polymerisation pressure and polymerisation temperature on MWD evaluated. A model, which includes chain transfer to polymer, was developed to predict the increase in polydispersity observed with increasing monomer concentration and the reasons for the formation of polymers with bimodal MWD at many of the operating conditions investigated are brieÁy considered. (3rd IUPAC-Sponsored International Symposium on Free-Radical Polymerization: Kinetics and Mechanism, Il Ciocco (Lucca), Tuscany, Italy, 3rd-9th June, 2001) USA

Accession no.860998 Item 136 Macromolecular Symposia Vol.182, 2002, p.31-42 PROPAGATION KINETICS IN FREE-RADICAL POLYMERIZATIONS Beuermann S Gottingen,Georg-August-Universitat The effect of Áuid or supercritical carbon dioxide on the kinetics of propagation of a range of monomers in bulk and solution was examined using a combination of pulsed laser initiated polymerisation and size exclusion chromatography. The role of local monomer concentrations in the vicinity of the propagating radical is discussed and the contribution of local monomer concentrations towards a better understanding of increases in propagation rate coefÀcients with ester size in acrylates and methacrylates and the inÁuence of initiating laser pulse repetition rate on propagation rate coefÀcients is considered. 34 refs. (3rd IUPAC-Sponsored International Symposium on Free-Radical Polymerization: Kinetics and Mechanism, Il Ciocco (Lucca), Tuscany, Italy, 3rd-9th June, 2001) EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.860992 Item 135 Macromolecular Symposia Vol.182, 2002, p.119-29 CONTINUOUS PRECIPITATION POLYMERIZATION OF VINYLIDENE

© Copyright 2005 Rapra Technology Limited

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References and Abstracts

Item 137 Macromolecules 35, No.12, 4th June 2002, p.4653-7 SOLUBILITY OF CF2-MODIFIED POLYBUTADIENE AND POLYISOPRENE IN SUPERCRITICAL CARBON DIOXIDE McHugh M A; Park I-H; Reisinger J J; Ren Y; Lodge T P; Hillmyer M A Virginia,Commonwealth University; Kumoh,National University of Technology; Minnesota,University The cloud points of Áuorinated polyisoprenes (FPI) and Áuorinated polybutadienes (FBR) in supercritical CO2 were investigated over the temperature range 60-170 C and the pressure range 100-300 MPa. Neither polyisoprene (PI) nor hydrogenated PI were soluble in CO2 at temperatures of up to 155 C and pressures of 260 MPa. Pressures in excess of 100 MPa were required to obtain single phase solutions of FPI and FBR. The cloud point curves of FPI and FBR exhibited temperature minima at approximately 60 and 80 C, respectively, attributed to increased CO2-CO2 and polymer-polymer interactions relative to polymer-CO2 interactions. The cloud point curves for FPI moved to higher pressures and temperatures with decreasing Áuorine content. It was concluded that the incorporation of Áuorine into macromolecules results in a signiÀcant increase of solubility in CO2. 25 refs. KOREA; USA

Accession no.857463 Item 138 Polymer Preprints. Volume 43, Number 1. Spring 2002. Papers presented at the ACS meeting held Orlando, Fl., 7th-11th April 2002. Washington D.C., ACS, Div.of Polymer Chemistry, 2002, p.473, 28 cm, 012 STUDY ON DEGRADATION OF PET IN SUPERCRITICAL ETHYLENE GLYCOL Hanfu Wang; Liang Chen; Xincai Liu; Yubin Zheng; Zhongwen Wu; Yunchun Zhou Jilin,University; Changchun,Institute of Applied Chemistry (ACS,Div.of Polymer Chemistry) The degradation of PETP in supercritical ethylene glycol was studied. Degradation products of different molecular weights could be obtained by controlling the system pressure, temperature or ratio of polymer to ethylene glycol. The oligomeric degradation products could be converted into unsaturated polyesters by reacting with maleic anhydride. 7 refs. CHINA

Accession no.857005 Item 139 Industrial and Engineering Chemistry Research 41, No.11, 29th May 2002, p.2617-22 REDUCTION OF RESIDUAL MONOMER

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IN LATEX PRODUCTS BY ENHANCED POLYMERIZATION AND EXTRACTION IN SUPERCRITICAL CARBON DIOXIDE Kemmere M; van Schilt M; Cleven M; van Herk A; Keurentjes J Eindhoven,University of Technology The reduction of methyl methacrylate in a PMMA latex was studied. Pulsed electron beam experiments were performed to study the effect of supercritical carbon dioxide on the monomer concentration inside the polymer particles during the polymerization reaction. The partitioning behaviour of methyl methacrylate between water and carbon dioxide was measured as a function of pressure and temperature. 28 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; NETHERLANDS; WESTERN EUROPE

Accession no.856799 Item 140 ACS POLYMERIC MATERIALS SCIENCE AND ENGINEERING. SPRING MEETING 2001. VOLUME 84. Proceedings of a conference in San Diego, Ca.. Washington, D.C., 2001, p.280-1, 012 EVALUATING THE SWELLING OF POLYMERS IN SUPERCRITICAL CARBON DIOXIDE Shenoy S L; Sebra R; Woerdeman D; Wynne K Virginia,Commonwealth University A simple and inexpensive technique to accurately determine the degree of swelling of the commercially available polymer Kraton in carbon dioxide. At ambient temperature and 2000 psi Kraton swells by approximately 7% in liquid carbon dioxide. A microcellular morphology is obtained on sudden depressurisation. The use of supercritical carbon dioxide to control and manipulate the properties of polymeric melts is rapidly becoming an important area of research. 7 refs. USA

Accession no.855570 Item 141 ACS POLYMERIC MATERIALS SCIENCE AND ENGINEERING. SPRING MEETING 2001. VOLUME 84. Proceedings of a conference in San Diego, Ca.. Washington, D.C., 2001, p.279, 012 RHEOLOGY OF POLYMER MELTS SWOLLEN WITH DISSOLVED SUPERCRITICAL FLUIDS Manke C W; Gulari E; Smolinski J M; Kwag C Wayne State,University The effects of dissolved gases on the rheology of polymer melts are important to applications such as the production of polymer foams and the synthesis and processing of polymers in supercritical Áuids. Dissolved supercritical gases can reduce the viscosity of polymer melts by 2 to 3 orders of magnitude under suitable conditions. Viscosity measurements for several polymer-supercritical Áuid systems are presented, including polystyrene, polymethyl methacrylate, and

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References and Abstracts

polydimethyl siloxane with dissolved carbon dioxide, and polystyrene with the refrigerant gases 1,1-diÁuoroethane (R152a) and 1,1,1,2-tetraÁuoroethane (R134a). For each system, conventional viscoelastic scaling techniques were used to reduce the composition-dependent viscosity versus shear rate relationships to master curves identical to the viscosity curve for the pure polymer. The dependence of the viscoelastic scaling factors on dissolved gas content is correlated by a simple free volume theory, combined with an equation-of-state model for the polymer-gas mixture. Also considered is the effect of dissolved gas on the glass transition temperature of the polymer-gas mixture.

carbon dioxide-assisted extrusion and as a blowing agent in the microcellular foaming process. 7 refs.

USA

DuPont Fluoropolymers is introducing what it claims are the first commercial fluoropolymers made using supercritical carbon dioxide. The nine grades now debuting globally are similar to Áuorinated ethylene propylene polymers, but are terpolymers containing some vinyl ether. The materials, designated TeÁon G, are much tougher than FEP. Toughness at 100C is 4.6 kJ/m3 versus 1.7 kJ/m3 for TeÁon FEP. Tensile strength retention with increasing temperature exceeds all current FEP polymers, while ultimate elongation also is much higher. The new polymers are particularly suitable for extrusion. Initial applications will focus on heat-shrink tubing, wire and cable insulation and industrial Àlm.

Accession no.855569 Item 142 ACS POLYMERIC MATERIALS SCIENCE AND ENGINEERING. SPRING MEETING 2001. VOLUME 84. Proceedings of a conference in San Diego, Ca.. Washington, D.C., 2001, p.276-8, 012 CO2-ASSISTED POLYMER PROCESSING: ACCESSING NEW PROCESSING WINDOWS AND NOVEL MORPHOLOGIES Royer J R; Siripurapu S; DeSimone J M; Spontak R J; Khan S A North Carolina,State University; North Carolina,University A detailed rheological investigation to help elucidate the advantages of carbon dioxide-induced plasticisation is presented. Several example cases, speciÀcally microcellular foaming and extrusion technology are discussed to demonstrate the utilisation of supercritical carbon dioxide as a plasticiser. Experimental measurements of viscosity as a function of shear rate, pressure, temperature and carbon dioxide concentration were carried out for various commercial polymer resins using an extrusion slit die rheometer. Carbon dioxide was demonstrated to be an excellent plasticiser for all samples measured, lowering the viscosity of the polymer melts by 25-80% depending on pressure, temperature and carbon dioxide concentration. A free-volume model was developed to predict the effects of carbon dioxide on melt rheology, using existing theories for viscoelastic scaling of polymer melts and the prediction of glass transition temperature depression by a diluent. Conventional viscoelastic scaling and data corrections were formed using the predictive free-volume model developed. Utilising only the freevolume theory, the experimental data was collapsed to a single master curve independent of pressure and carbon dioxide concentration for each of the three polymer resins. A predictive tool to quantify the viscosity reduction of polymer melts due to plasticisation by carbon dioxide or other diluents is therefore possible from the combination of conventional viscoelastic scaling and free volume theory with thermodynamic models. This prediction assists in the design of novel extrusion processes and in understanding the ability of carbon dioxide to act as a processing aid for

© Copyright 2005 Rapra Technology Limited

USA

Accession no.855568 Item 143 Modern Plastics International 32, No.5, May 2002, p.35 NEW SOLVENT PROVES CRITICAL TO MAKING IMPROVED FLUOROPOLYMERS Rosenzweig M

DUPONT FLUOROPOLYMERS USA

Accession no.855046 Item 144 Blowing Agents and Foaming Processes 2002. Proceedings of a conference held Heidelberg, 27th-28th May 2002. Shawbury, Rapra Technology Ltd., 2002, Paper 8, p.7985, 29cm, 012 NEW DEVELOPMENTS IN MUCELL MICROCELLULAR FOAM MOULDING TECHNOLOGY AND COMMERCIAL APPLICATIONS Janisch R Trexel USA (Rapra Technology Ltd.) The MuCell microcellular foam injection moulding process, which provides plastics components that are lighter, Áatter, straighter and more dimensionally stable at extreme operating temperatures compared to conventionally moulded components, and the hardware necessary to adapt the process are brieÁy described. The cost beneÀts of the process are indicated and a range of products manufactured using the process, which employs supercritical fluids of inert gases to create evenly distributed and uniformly sized microscopic cells throughout the polymer, by companies from as far aÀeld as Australia and Singapore are illustrated. 5 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; USA; WESTERN EUROPE

Accession no.854592

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References and Abstracts

Item 145 Polymer Preprints, Volume 42, No.2, Fall 2001, Conference proceedings. Chicago, Il., Fall 2001, p.554-5 CONTINUOUS AND BATCH POLYMERISATIONS OF VINYLIDENE FLUORIDE IN DENSE CARBON DIOXIDE Wojeiski L M; Saraf M K; Roberts G W; DeSimone J M North Carolina,State University; North Carolina,Chapel Hill University (ACS,Div.of Polymer Chemistry) As an environmentally benign solvent, supercritical carbon dioxide (scCO2) has shown potential as a viable medium for a number of chemical processes, including the polymerisation of Áuorinated oleÀns. A green process has been developed, which allows for the continuous polymerisation of Áuorinated monomers via free radical precipitation polymerisation in scCO2 in a continuous stirred tank reactor (CSTR). It was hoped that by carrying out these polymerisations in a CSTR, the environmental beneÀts of CO2-based polymerisations could be coupled with the process advantages of using a continuous system. Although it has been possible to achieve desirable conversions of monomer, molecular weight of the polymers produces in this system has been lower than desired. A small-scale polymerisation system is implemented which allows for rapid screening of polymerisation conditions and initiators, in this case, for the free radical precipitation polymerisation of vinylidene Áuoride. The Áuorinated initiators examined are active at lower temperatures relative to non-Áuorinated initiators, which opens up the possibility of preparing high molecular weight polymer under reasonably mild reaction conditions. These lower reaction temperatures lead to an increase in the Tm of the polymer to one comparable with commercially available PVDF. NMR analysis of these polymers shows a reduced tendency to reverse added monomer units, and shows a lower concentration of end-groups, indicating that these materials have higher Mn’s relative to those prepared at high temperatures. 3 refs. USA

Accession no.853927 Item 146 Macromolecules 35, No.10, 7th May 2002, p.3866-9 PRESSURE AND TEMPERATURE DEPENDENCE OF THE PROPAGATION RATE COEFFICIENT OF FREE-RADICAL STYRENE POLYMERIZATION IN SUPERCRITICAL CARBON DIOXIDE Beuermann S; Buback M; Isemer C; Lacik I; Wahl A Gottingen,University; Slovak Academy of Sciences Free radical polymerisation of styrene in homogeneous phase of supercritical carbon dioxide was studied at temperatures between 40 and 80 C and pressures between 300 and 1500 bar. Propagation rate coefÀcients were

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obtained using pulsed-laser polymerisation in conjunction with size-exclusion chromatography. The points of inflection were determined from maxima of the first derivative curve of the experimental MWD. 11 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; SLOVAK REPUBLIC; SLOVAKIA; WESTERN EUROPE

Accession no.853624 Item 147 Macromolecules 35, No.9, 23rd April 2002, p.3653-61 KINETICS OF THE EARLY STAGE OF DISPERSION POLYMERIZATION IN SUPERCRITICAL CARBON DIOXIDE AS MONITORED BY TURBIDIMETRY. II. PARTICLE FORMATION AND LOCUS OF POLYMERIZATION Fehrenbacher U; Ballauff M Karlsruhe,University The dispersion polymerisation of methyl methacrylate was studied in supercritical carbon dioxide at 330 bar in situ by turbidimetry. All the experiments were conducted in the presence of the macromonomer polydimethylsiloxanemonomethacrylate which acted as a stabiliser. The formation of particles of PMMA was monitored quantitatively by turbidimetry because the degree of swelling by supercritical carbon dioxide, as well as the refractive index of these particles, was known accurately. The turbidity spectra were measured in the range 400 to 950 nm. The number density and the diameter could be obtained as a function of time in the earliest stage of the dispersion polymerisation with a time resolution of about 0.1 s. Furthermore, the mass of polymer could be deduced and thus a full kinetic analysis performed. Particular attention was paid to the size distribution of particles which was shown to play an essential role in the treatment of turbidimetric data. 30 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.853390 Item 148 Macromolecules 35, No.9, 23rd April 2002, p.3569-75 SYNTHESIS OF FLUOROCARBON-VINYL ACETATE COPOLYMERS IN SUPERCRITICAL CARBON DIOXIDE: INSIGHT INTO BULK PROPERTIES Baradie B; Shoichet M S Toronto,University A series of Áuorocarbon-vinyl acetate(VAc) copolymers was prepared in supercritical carbon dioxide with a broad range of compositions, high yields and high molec. wts. It was shown that surfactant-free carbon dioxide polymerisation of all three Áuorocarbons studied (tetraf luoroethylene(TFE), chlorotriÁuoroethylene(CTFE) and

© Copyright 2005 Rapra Technology Limited

References and Abstracts

vinylidene Áuoride(VDF)) with VAc was possible and that P(TFE-VAc) was linear. All the TFE-VAc copolymers had high yields and high molec.wts., suggesting good solubility in carbon dioxide. CTFE-VAc copolymers were synthesised in high yield when less than 50 mol % CTFE was in the feed. At higher concentrations of CTFE, the gradual consumption of VAc resulted in lower polymer yields and molec.wts., suggesting that CTFE was less soluble than TFE in carbon dioxide. VDF-VAc copolymers were synthesised with the lowest yields of the three Áuorocarbons studied due to the decreased reactivity (and probably carbon dioxide solubility) of VDF relative to VAc. 35 refs. CANADA

Accession no.853379

and synthesise novel materials with both strongly polar groups and highly CO2-philic segments. Synthetic polymers with pendent carbohydrate moieties and a stable C-C backbone are referred to as glycopolymers, which are water-soluble and have many potential applications in biochemical and biomedical Àelds. Novel amphiphilic block copolymers with well-defined glycopolymer and fluoropolymer blocks are reported using living anionic polymerisation. Both protected (hydrophobic/ CO2-philic) and deprotected (hydrophilic/CO2-philic) copolymers are CO2 amphiphiles and their solubility in CO2 is heavily inÁuenced by the amphiphilic structure. The emulsion polymerisation of N-ethylacrylamide in CO2 is successfully performed by using the hydrophilic deprotected block copolymer. 7 refs. USA

Item 149 Macromolecules 35, No.9, 23rd April 2002, p.3325-7 RIGID PORE STRUCTURE FROM HIGHLY SWOLLEN POLYMER GELS Winter H H; Gappert G; Ito H Massachusetts,University

Accession no.849822

A crosslinked PE specimen, when exposed to a suitable pressure-temp. cycle in the presence of supercritical propane, was shown to increase its size several fold and to develop an open-pore structure. The process was genuine and was expected to be applicable to other semicrystalline polymers which could be crosslinked and swollen. It provided a relatively simple method for obtaining high value-added materials from commodity polymers such as PE or from approved biopolymers. When supercritical Áuids were used as the swelling Áuid, the process was capable of producing extremely high-purity materials with zero emissions. 15 refs.

DuPont has launched a range of six high-performance melt processable PTFE resins, the first commercial products to be manufactured using its supercritical CO2 polymerisation technology. Process G uses supercritical CO2 in place of water used in traditional emulsion polymerisation of Áuoropolymers. The Àrst Process G resins are targeted at heat shrink tubing, high-performance Àlms and high temperature cable sleeving. Property data are presented. DUPONT CO.

Item 151 Plastics and Rubber Weekly 5th April 2002, p.9 SUPERCRITICAL DEBUT Smith C

USA

Accession no.849679

USA

Accession no.853346 Item 150 Polymer Preprints. Volume 42, Number 2, Fall 2001. Proceedings of a conference held Chicago, Il., 26th-30th August 2001. Washington D.C., ACS,Div.of Polymer Chemistry, 2001, p.340-1 LIVING ANIONIC POLYMERISATIONS OF WELL-DEFINED SUGAR-CONTAINING DIBLOCK FLUOROCOPOLYMER AND ITS APPLICATION IN CO2 EMULSION POLYMERISATIONS Ye W; DeSimone D M North Carolina,University (ACS,Div.of Polymer Chemistry) Carbon dioxide as a useful processing Áuid is limited by its inability to solubilise highly polar compounds. This problem can be alleviated by the addition of CO2philic amphiphiles. The primary objective is to design

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Item 152 Macromolecules 35, No.3, 29th Jan.2002, p.934-40 POLY(METHYL METHACRYLATE) AND POLY(BUTYL METHACRYLATE) SWELLING IN SUPERCRITICAL CARBON DIOXIDE Nikitin L N; Said-Galiyev E E; Vinokur R A; Khokhlov A R; Gallyamov M O; Schaumburg K Russian Academy of Sciences; Moscow,Lomonosov University; Copenhagen,University The swelling of PMMA and poly(butyl methacrylate) in supercritical carbon dioxide was studied by means of direct optical observation. The diffusion coefÀcients of carbon dioxide molecules in the polymers were determined by analysing the diffusion front propagation in the polymers and by volumetric measurements of the swelling kinetics for different temperatures and pressures. The results from the two methods were in good agreement. A difference in the appearance of diffusion fronts in these polymers with different glass transition temperatures was observed. The

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References and Abstracts

results were discussed. 26 refs. DENMARK; EUROPEAN COMMUNITY; EUROPEAN UNION; RUSSIA; SCANDINAVIA; WESTERN EUROPE

Accession no.848202 Item 153 Chemical and Engineering News 80, No.10, 11th March 2002, p.17 DUPONT DEBUTS FLUOROPOLYMERS DuPont has introduced the Àrst commercial Áuoropolymers made with a new polymerisation process based on supercritical carbon dioxide. The products, meltprocessable polymers for applications such as wire and cable insulation, are produced at a 40m US dollars facility in Fayetteville, N.C., that started up in late 2000. The technology was developed jointly by scientists at DuPont and at the University of North Carolina, Chapel Hill. This abstract includes all the information contained in the original article. DUPONT CO. USA

Accession no.847773 Item 154 ACS POLYMERIC MATERIALS SCIENCE AND ENGINEERING. SPRING MEETING 2001. VOLUME 84. Proceedings of a conference in San Diego, Ca.. Washington, D.C., 2001, p.270-1, 012 PROGRESS IN RESEARCH OF RAPID EXPANSION OF SUPERCRITICAL SOLUTIONS (RESS) TECHNIQUE OF DROPLET FORMATION OF PERFLUOROPOLYETHER FOR COATING APPLICATION Montero G A; Robert H B; Carbonell R G; DeSimone J M North Carolina,State University; North Carolina,University (AMERICAN CHEMICAL SOCIETY) A discussion is given of progress in research into the rapid expansion of supercritical solutions (RESS) technique of droplet formation of perÁuoropolyether for coating applications. The objective was to gain an understanding of the relationship between morphology of precipitate, droplet size, spray characteristics and RESS process conditions. It was demonstrated that small droplet size and a narrow droplet size distribution can be achieved in the system by using the RESS technique. RESS is a very promising technology because in principle small droplets and particles can be obtained with a narrow (monodisperse) size distribution. The technique for droplet size formation that has been demonstrated avoids the use of organic solvents for polymer coating applications. 3 refs. USA

Accession no.846723

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Item 155 ACS POLYMERIC MATERIALS SCIENCE AND ENGINEERING. SPRING MEETING 2001. VOLUME 84. Proceedings of a conference in San Diego, Ca.. Washington, D.C., 2001, p.203, 012 MULTICOMPONENT POLYMER SYSTEMS IN THE PRESENCE OF SUPERCRITICAL CARBON DIOXIDE Walker T A; Siripurapu S; Young J L; Hirsch S G; Khan S A; DeSimone J M; Spontak R J North Carolina,State University; North Carolina,University (AMERICAN CHEMICAL SOCIETY) The presence of supercritical carbon dioxide, which plasticises a broad range of polymers, can greatly affect the phase behaviour of multicomponent polymer systems. This effect was studied by investigating three related areas. The Àrst was an investigation into the extent to which supercritical carbon dioxide shifts the phase boundaries of polymethyl methacrylate/polyvinylidene fluoride (PMMA/PVDF) and polymethyl mercaptoacetamide/ polyvinylidene Áuoride (PEMA/PVDF) blends, which display lower critical solution temperature (LCST) behaviour. The second area was the extent to which supercritical carbon dioxide and high-pressure nitrogen inÁuence the cloud point of polydimethyl siloxane(PEMS) (upper critical solution temperature, UCST) blends. Within the context of microcellular polymer foams, polymer miscibility issues were considered. Through the liberal addition of PMMA, microcellular polymer foams of PVDF have been generated continuously in batch mode with very good homogeneity. The third area was a study of polystyrene/PMMA latex particles produced by emulsion polymerisation in supercritical carbon dioxide. A presentation is given of morphological characteristics discerned by transmission electron microtomography. USA

Accession no.846684 Item 156 ACS POLYMERIC MATERIALS SCIENCE AND ENGINEERING. SPRING MEETING 2001. VOLUME 84. Proceedings of a conference in San Diego, Ca.. Washington, D.C., 2001, p.195-6, 012 RELATIONSHIP BETWEEN MACROSCOPIC SCF-POLYMER PHASE BEHAVIOUR AND SOLUTION MICROSTRUCTURE Hugh M A M; van Zanten J H; DiNoia T P Virginia,Commonwealth University; North Carolina,State University (AMERICAN CHEMICAL SOCIETY) The relationship between macroscopic supercritical fluid- (SCF)-polymer phase behaviour and solution microstructure was investigated. The aim was to identify whether differences exist on a microscopic level between the quality of a liquid and an SCF solvent. Analysis was carried out using small angle neutron scattering of

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References and Abstracts

polyethylene butene in dimethyl ether. It was found that very high pressures are required to dissolve most polymers in SCF solvents. Typical SCF solvents are low molecular, high volatility gases at room temperature, which is an indication of very low cohesive energy. Pressure can be used to modulate the strength of interactions with an SCF solvent, however, whereas pressure has very little impact on liquid solvent strength. The concentration Áuctuations in an SCF solvent environment are larger than those in a liquid solvent environment even at similar distances to the phase boundary. 10 refs. USA

Accession no.846680 Item 157 Colloid and Polymer Science 280, No.2, Feb. 2002, p.183-7 PRODUCTION OF SUBMICRON-SIZED POLYMETHYL METHACRYLATE PARTICLES BY DISPERSION POLYMERIZATION WITH A POLYDIMETHYLSILOXANE-BASED AZOINITIATOR IN SUPERCRITICAL CARBON DIOXIDE Okubo M; Fujii S; Maenaka H; Minami H Kobe,University Details are given of the preparation of submicron-sized PMMA particles by dispersion polymerisation using a PDMS-based azo initiator in supercritical carbon dioxide. The initiator was found to operate not only as a radical initiator but also as a colloidal stabiliser. Characterisation was undertaken using SEM, proton NMR and X-ray photoelectron spectroscopy. 19 refs. JAPAN

Accession no.845782 Item 158 Kobunshi Ronbunshu 58, No.12, 2001, p.714-7 Japanese SORPTION PROPERTIES OF SUPERCRITICAL CARBON DIOXIDE IN POLY(ETHYLENE GLYCOL) AND POLY(ETHYLENE OXIDE) WITH HIGH-PRESSURE THERMOGRAVIMETRYDIFFERENTIAL THERMAL ANALYSIS Hata K-A Japan,Chemical Innovation Institute An in-situ high-pressure TGA-DTA method based on magnetic suspension was employed to investigate the sorption of and plasticisation effect of supercritical carbon dioxide in molten PEG and PEO. It was found that sorption of carbon dioxide increased almost linearly with pressure and that compressed carbon dioxide depressed the melting points of the polymers, which decreased linearly with the pressure of the carbon dioxide. 11 refs. JAPAN

Accession no.845103

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Item 159 Kobunshi Ronbunshu 58, No.12, 2001, p.710-3 INFUSION OF THE ORGANOMETALLIC COMPOUND INTO ORGANIC MATERIALS USING SUPERCRITICAL CARBON DIOXIDE Nakanishi T Japan,Chemical Innovation Institute The results are reported of a study of the infusion of Ti(Oi-C3H7)4 into PMMA using supercritical carbon dioxide. The titanium compound was infused into the surface of the polymer at low temperatures and diffused further into the polymer with increasing pressure under constant temperature. It reacts to produce clusters, which could be controlled by temperature and pressure. 7 refs. JAPAN

Accession no.845102 Item 160 Kobunshi Ronbunshu 58, No.12, 2001, p.703-9 Japanese DECOMPOSITION OF SILANE-CROSSLINKED POLYETHYLENE FOR MATERIAL RECYCLING BY USING SUPERCRITICAL METHANOL Goto T; Yamazaki T; Okajima I; Sugeta T; Miyoshi T; Hayashi S; Sako T Hitachi Cable Ltd.; Shizuoka,University; Japan,National Institute of Advanced Industrial Science & Technology Silane-crosslinked PE was decomposed using supercritical water and supercritical methanol and decomposition investigated by means of NMR spectroscopy and FTIR spectroscopy. Heating of the crosslinked PE in supercritical methanol at 300 to 340C and 8 to 10 MPa for 30 min. gave rise to a thermoplastic PE having a number-average molec. wt. of about 40,000 and no gel fraction. The data obtained indicated that the decomposition of PE using supercritical methanol was suitable for recycling silane-crosslinked polyethylene. 17 refs. JAPAN

Accession no.845101 Item 161 Kobunshi Ronbunshu 58, No.12, 2001, p.697-702 Japanese DECOMPOSITION OF AROMATIC POLYAMIDE USING SUPERCRITICAL WATER Takahashi K; Sato Y; Kato K; Nishi S Lifestyle & Environmental Technology Laboratories; Nippon Telegraph & Telephone Corp. Poly(p-phenylene terephthalamide) was decomposed using supercritical water in a batch reactor at temperatures ranging from 300 to 600C and at temperatures ranging from 10 to 60 mins. Decomposition products were identiÀed by HPLC and gas chromatography-mass spectrometry and

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References and Abstracts

compared with those obtained when decomposition was performed in a Áow reactor. The data obtained indicated that the mass-scale feedstock recycling of polyamide is possible. 4 refs. JAPAN

Accession no.845100 Item 162 Kobunshi Ronbunshu 58, No.12, 2001, p.692-702 Japanese DECOMPOSITION AND DEBROMINATION OF FLAME-RESISTANT POLYMERS CONTAINING BROMINE ATOMS WITH SUBCRITICAL WATER Okajima I; Sugeta T; Sako T Shizuoka,University; Japan,National Institute of Advanced Industrial Science & Technology The decomposition and debromination of tetrabrominated bisphenol A epoxy resin were investigated using subcritical and supercritical water. Decomposition products were identiÀed and hydrolysis with subcritical water compared with the pyrolysis of brominated epoxy resin. Hydrolysis with subcritical water inhibited carbonisation and accelerated bromine abstraction from the epoxy resin. 6 refs. JAPAN

Accession no.845099 Item 163 Kobunshi Ronbunshu 58, No.12, 2001, p.661-73 Japanese CONVERSION OF POLYETHYLENE TO OIL USING SUPERCRITICAL WATER AND DONATION OF HYDROGEN IN SUPERCRITICAL WATER Moriya T; Enomoto H Tohoku Electric Power Co.Inc.; Tohoku,University Thermal cracking and cracking in supercritical water of PE were carried out and the species, yields and structures of the cracked products investigated. The mechanism of degradation was also studied and supercritical water cracking compared with thermal cracking. Experiments were also carried out using D2O as a tracer and the stages involved in the donation of hydrogen from the supercritical water to the oil identiÀed. 28 refs. JAPAN

Accession no.845098 Item 164 Kobunshi Ronbunshu 58, No.12, 2001, p.631-41 Japanese POLYETHYLENE DECOMPOSITION VIA PYROLYSIS AND PARTIAL OXIDATION IN

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SUPERCRITICAL WATER Watanabe M; Adschiri T; Arai K Tohoku,University Polyethylene was degraded in a batch reactor at 420C for 30 min. and the effect of supercritical water on degradation investigated. The enhancement of decomposition observed was attributed to the dissolution of high molec. wt. hydrocarbons in the supercritical water and diffusion of water into the molten PE phase. The yield of partial oxidation products increased with the increasing density of supercritical water and partial oxidation was affected by the area of the interface between the molten PE and water-oxygen phase. 17 refs. JAPAN

Accession no.845096 Item 165 160th ACS Rubber Division Meeting - Fall 2001. Cleveland, Oh., 16th-18th October 2001, Paper 38, pp.24, 012 DEVULCANIZATION OF SULFUR-CURED ISOPRENE RUBBER IN SUPERCRITICAL CARBON DIOXIDE Kojima M; Ogawa K; Mizoshima H; Tosaka M; Kohjiya S Toyo Tire & Rubber Co.Ltd.; Kyoto,University (ACS,Rubber Div.) The devulcanisation of unÀlled isoprene rubber using devulcanising reagents in supercritical carbon dioxide was studied. In the supercritical gas, thiophenol/-n-butylamine and diphenyl disulphide devulcanised the vulcanisates effectively into chloroform-soluble polymer with molec. wt. of tens of thousands. The vulcanisates were degraded to sol fractions more easily with higher contents of polysulphidic crosslink using thiophenol/n-butylamine as a devulcanising reagent. Supercritical carbon dioxide assisted the diffusion of devulcanising reagents into the vulcanisates. The devulcanisation made progress more efÀciently in supercritical Áuid of carbon dioxide than in the gaseous state. 24 refs. USA

Accession no.842975 Item 166 Revue Generale des Caoutchoucs et Plastiques 78, No.796, June/July 2001, p.40-5 French INJECTION MOULDING OF TECHNICAL PARTS: FOUR PROCESSES UNDER EXAMINATION Delannoy G An examination is made of developments in four recently introduced plastics injection moulding processes, including sequential, two-material/multi-material and water-assisted injection moulding and the MuCell process developed by Trexel for the injection moulding of microcellular products

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References and Abstracts

using supercritical gases as blowing agents. Types of polymers processed and products manufactured by these techniques are reviewed. TREXEL USA; WORLD

Accession no.842593 Item 167 Plastics Engineering 57, No.5, May 2001, p.46-51 INJECTION MOULDING INNOVATION: THE MICROCELLULAR FOAM PROCESS Pierick D; Jacobsen K Trexel Inc.; Engel North America The microcellular foam moulding method known as the MuCell process uses supercritical Áuids of atmospheric gases to create evenly distributed and uniformly sized microscopic cells throughout a polymer. Suitable for injection moulding, the microcellular foam process enhances product design, improves processing efÀciency and reduces product costs. The technology offers weight reduction, cycle time improvements, reduced injection pressures and clamp tonnage, and energy savings. A polystyrene case study is presented which investigates Àve primary variables: injection speed, melt temperature, gas type, mould temperature and gas level in weight percent. CANADA; USA

Accession no.842319 Item 168 ACS Polymeric Materials Science and Engineering. Spring Meeting 2001. Volume 84. Proceedings of a conference in San Diego, Ca.. Washington, D.C., 2001, p.45-6. 012 FREE-RADICAL COPOLYMERIZATIONS OF STYRENE AND METHACRYLIC ACID ESTERS IN HOMOGENEOUS PHASE OF SUPERCRITICAL CARBON DIOXIDE Beuermann S; Buback M; Jurgens M Gottingen,Georg-August-Universitat Phase behaviour measurements and copolymer syntheses show that free-radical binary and ternary copolymerisations of styrene with functional methacrylates such as, for example, glycidyl methacrylate, 2-hydroxypropyl methacrylate or ibornyl methacrylate might be carried out in homogeneous phase in the presence of supercritical carbon dioxide up to high degrees of monomer conversion. Terpolymerisations of styrene with methyl methacrylate and glycidyl methacrylate were modelled using the software program PREDICI. Currently developed are strategies either for a batch or a continuous polymerisation process leading to a uniform copolymer composition. 7 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.841552

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Item 169 ACS Polymeric Materials Science and Engineering. Spring Meeting 2001. Volume 84. Proceedings of a conference in San Diego, Ca.. Washington, D.C., 2001, p.39-43. 012 PHARMACEUTICAL MATERIAL PRODUCTION VIA SUPERCRITICAL FLUIDS EMPLOYING THE TECHNIQUE OF PARTICLES FROM GASSATURATED SOLUTIONS (PGSS) Mandel F S; Wang J D; McHugh M A Ferro Corp.,Technical Center; Virginia,Commonwealth University For the production of many performance materials at Ferro Corp. A versatile and Áexible supercritical carbon dioxide manufacturing process, SF MicronMix, was developed and deployed. The supercritical Áuid-aided processing exploits the change in polymer properties that occurs when the polymer is contacted with an SCF solvent. Polymers considered include polylactide-co-glycolide. It is usually not necessary to dissolve the polymer to be processed, which is advantageous because the high pressures and temperatures required to dissolve polymers in supercritical Áuids have a severe negative impact on process economics. By interpretation using the principles of molecular thermodynamics, guidelines for the type of repeat groups that leads to polymer solubility in supercritical Áuid solvents at low temperatures and pressures are obtained. 58 refs. USA

Accession no.841551 Item 170 ACS Polymeric Materials Science and Engineering. Spring Meeting 2001. Volume 84. Proceedings of a conference in San Diego, Ca.. Washington, D.C., 2001, p.37-8. 012 OPEN-PORE MORPHOLOGIES BY CRYSTALLIZATION OF CROSSLINKED, POLYETHYLENE GELS SWOLLEN WITH SUPERCRITICAL PROPANE Gappert G; Ito H; Winter H H Massachusetts,University Crosslinked polyethylene was crystallised from supercritical propane to create open-pore structures in pre-shaped samples. A metallocene LLDPE was moulded from pellet into a Áat sheet and then radiation crosslinked in an inert atmosphere. The shaped, crosslinked sample was then swollen with its critical point to prevent the formation of a liquid phase during pore evacuation. Samples which contained a fraction of uncrosslinked chains were partially extracted during the swelling step. All samples displayed a rise in volume and decrease in density and maintained their original moulded shape. Scanning electron microscopy reveals pore sizes ranging from about 0.25 microns to 10 microns. Propane is recovered completely in high purity and leaves no residue in the porous polyethylene. 10 refs. USA

Accession no.841550

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Item 171 Polymer Degradation and Stability 75, No.1, 2002, p.185-91 STUDY ON METHANOLYTIC DEPOLYMERIZATION OF PET WITH SUPERCRITICAL METHANOL FOR CHEMICAL RECYCLING Yong Yang; Yijun Lu; Hongwei Xiang; Yuanyuan Xu; Yongwang Li Chinese Academy of Sciences Polyethylene terephthalate (PET) was subjected to methanolytic depolymerisation with supercritical methanol in a stirred stainless steel autoclave at temperatures of 523543 deg.C, pressure 8.5-14.0 MPa, and a 3-8 methanol to PET weight ratio. The solid products obtained, consisting mainly of dimethyl terephthalate and small amounts of methyl-(2-hydroxyethyl) terephthalate, bis(hydroxyethyl) terephthalate, dimers, and oligomers, were analysed by high performance liquid chromatography (HPLC), and the liquid products, mainly ethylene glycol and methanol were analysed by gas chromatography (GC). The temperature, weight ratio of methanol to PET, and the reaction time had a very marked effect on dimethyl terephthalate yield and the degree of PET depolymerisation, but the effect of pressure was insigniÀcant above the methanol critical point. The optimum PET depolymerisation conditions were: temperature 533-543 K, pressure 9.0-11.0 MPa, and a methanol to PET weight ratio of 6-8. The depolymerisation of several PET wastes from the Chinese market was studied under the optimum conditions. 28 refs. CHINA

Accession no.841527 Item 172 Asia PaciÀc Coatings Journal 14, No.6, Dec. 2001, p.557-63 DECOMPOSITION OF FIBER REINFORCED PLASTICS USING FLUID AT HIGH TEMPERATURE AND PRESSURE Sugeta T; Nagaoka; Otake K; Sako T Japan,National Institute of Advanced Industrial Science & Technology; Kumamoto,Industrial Research Institute; Shizuoka,University An investigation is reported of the decomposition of Àbre-reinforced plastics, being refractory waste, using a supercritical water and alkali solution with alcohol at high temperature and pressure. Fibre-reinforced unsaturated polyester was treated by supercritical water at 380 degrees C and most of the matrix was decomposed during 5 minutes reaction time. The main products were carbon dioxide and carbon monoxide in gas phase, and styrene derivatives and phthalic acid in liquid phase. After the treatment with supercritical water for 5 minutes, no signiÀcant change in the Àbre recovered was detected using scanning electron microscopy or infrared spectroscopy. On the other hand, phenolic resin used as a matrix of CFRP was not decomposed using only supercritical water, but was

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promoted by supercritical water with alkali. Futhermore, with used of alcohol-alkali aqueous solution at a high temperature, phenolic resin was found to be mostly broken down to soluble products. 15 refs. JAPAN

Accession no.840528 Item 173 Asia PaciÀc Coatings Journal 14, No.6, Dec. 2001, p.552-6 POLYMERIZATION OF GLYCIDYL METHACRYLATE IN SUPERCRITICAL CARBON DIOXIDE Matsuyama K; Mishima K; Hirabaru T; Takahashi K Fukuoka,University; Konoshima Chemical Co.Ltd. Polyglycidyl methacrylate was synthesised in supercritical carbon dioxide and its solubility in carbon dioxide was measured by observing the cloud point. The inÁuences of the reaction pressure, monomer and initiator concentrations were investigated. Furthermore, the effects of methacrylic acid and a Áuorous surfactant on the polymer morphology were also discussed. Polymer particles were obtained by the addition of methacrylic acid and the Áuorous surfactant. Spherical particles were produced by the addition of methacrylic acid. 16 refs. JAPAN

Accession no.840527 Item 174 Kobunshi Ronbunshu 58, No.10, 2001, p.548-51 Japanese MONOMERIZATION OF NYLON 6 IN SUB-AND SUPERCRITICAL WATER Goto M; Umeda M; Kodama A; Hirose T; Nagaoka S Kumamoto,University; Kumamoto,Industrial Research Institute Nylon-6, a polymer synthesised by ring-opening polymerisation of epsilon-caprolactam, was decomposed by hydrolysis in sub- and supercritical water. Nylon 6 and degassed water were charged into a batch reactor and heated to a reaction temperature in the range of 573~673 K for 5 to 60 mins. In a salt bath. The liquid phase of the product was analysed by HPLC and GC-MS. As a result of HPLC analysis, epsilon-caprolactam and epsilonaminocaproic acid were detected in the product liquid phase. The yields of monomer components were plotted as a function of reaction time and temperature. The total yields of these monomers were about 100% for reactions at 573 K in 60 mins. and at 603 K in 30 mins. The yield of e-aminocaproic acid decreased rapidly as reaction time increased. Nylon 6 was decomposed by hydrolyis to epsilon-aminocaproic acid followed by cyclodehydration to epsilon-caprolactam or decomposition further to smaller molecules in sub- and supercritical water. 6 refs. JAPAN

Accession no.840526

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References and Abstracts

Item 175 Kobunshi Ronbunshu 58, No.10, 2001, p.533-40 Japanese NONCATALYTIC ORGANIC SYNTHESIS OF EPSILON-CAPROLACTAM AND DECOMPOSITION OF NYLON 6 USING SUPERCRITICAL WATER Sato O; Ikushima Y Japan,National Institute of Advanced Industrial Science & Technology

Item 177 Kobunshi Ronbunshu 58, No.10, 2001, p.489-94 Japanese PREPARATION OF POLY(PHENYLACETYLENE) USING SUPERCRITICAL OR LIQUID CARBON DIOXIDE Hori H; Six C; Leitner W Max-Planck-Institut fuer Kohlenforschung; Japan,National Institute of Advanced Industrial Science & Technology

Non-catalytic Beckmann rearrangement of cyclohexanoneoxime into epsilon-caprolactam was conÀrmed to be signiÀcantly promoted near the critical temperature in subcritical and supercritical water. High temperature, high pressure FTIR was further used to study the reactivities, in which it was demonstrated that supercritical water acts effectively in place of conventional acid catalysts. The rate constant in the Áow reaction system nylon 6 was successfully decomposed to epsilon-caprolactam in supercritical water at 653 K and 25 Mpa, in which the yield of epsilon-caprolactam reached 91%, even in short reaction times ranging from 6-7 minutes. 23 refs.

Polymerisation of phenylacetylene was carried out with high efÀciency in supercritical or liquid carbon dioxide using rhodium catalysts. The polymerisation rate in carbon dioxide is higher than in conventional solvents such as THF or hexane. The polymers consist of cis-transoidal and cis-cisoidal species. The surface morphology, molecular weight, IR and NMR spectroscopic properties of the resulting polymers are compared to those obtained by polymerisation in conventional solvents, and discussed in terms of the microstructure of the polymers. 32 refs.

JAPAN

Accession no.840522

EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; JAPAN; WESTERN EUROPE

Accession no.840525 Item 176 Kobunshi Ronbunshu 58, No.10, 2001, p.521-6 Japanese FLUID DENSITY DEPENDENCE OF THE PARTITION COEFFICIENT OF DISPERSE DYES BETWEEN SYNTHETIC FIBER AND SUPERCRITICAL CARBON DIOXIDE IN SUPERCRITICAL DYEING Tataba I; Miyagawa S; Lyu J H; Cho S M; Hori T Fukui,University; Pusan,National University PETP and PP fibres were dyed with two different disperse dyes in supercritical carbon dioxide Áuid. The partition coefÀcients of dyes between polymer phase and supercritical carbon dioxide phase were calculated from the equilibrium dye uptake and the solubilities of dyes in supercritical carbon dioxide. A liner relation was found, and the slope of the plots was shown to be roughly dependent on the solvation number of the dye in supercritical carbon dioxide for all polymer-dye systems. These thermodynamic analyses for the equilibrium dyeing are claimed to offer some important information regarding dye selection, the design of dyeing equipment and the optimisation of the dyeing process. In addition, the results are applicable for impregnation processes of polymers using supercritical carbon dioxide. 24 refs.

Item 178 Journal of Injection Molding Technology 5, No.3, Sept.2001, p.152-9 MICROCELLULAR FOAM PROCESSING IN RECIPROCATING-SCREW INJECTION MOLDING MACHINES Jingyi Xu; Pierick D Trexel Inc. A microcellular foam processing system for the reciprocating-screw injection moulding machine was developed. The design criteria derived provided the necessary conditions for creating and maintaining a singlephase solution in the overall system of the plasticising unit, supercritical Áuid(SCF) delivery unit and hydraulic unit. An overall systems approach was the key to successful implementation of a microcellular foam process. These modiÀcations are described, together with the component designs required for a microcellular foam moulding machine. The important components discussed are the plasticising unit, injection unit, hydraulic unit, clamp unit and SCF unit. The general guidelines for designing an injection moulding machine for microcellular foam are listed as the conclusions. 18 refs. USA

Accession no.840081

JAPAN; KOREA

Accession no.840524

© Copyright 2005 Rapra Technology Limited

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References and Abstracts

Item 179 Journal of Industrial Textiles 31, No.1, July 2001, p.43-56 PROGRESS IN SUPERCRITICAL CO2 DYEING Hendrix W A North Carolina,State University Supercritical Áuids have special properties that could lead to substantial improvement when utilised as replacements for water in wet processing of textiles. These Áuids have densities and solvating powers similar to liquid solvents combined with viscosity and diffusion coefÀcients like those observed for gases. In particular these make supercritical carbon dioxide (SC-CO2) one of the most beneÀcial and acceptable solvents used in manufacturing processes today. Therefore it is anticipated that commercial textile processes using SC-CO2 will have many advantages when compared to conventional aqueous processes. Successful commercialisation of SC-CO2 in processing will improve the economics of dyeing and other textile chemical processes by eliminating wastewater discharges, reducing consumption, eliminating drying and reducing air emissions. As a result, the use of SC-CO2 is expected to make textile processing more economical and environmentally friendly. An overview of the status of the research is presented, together with the technical and economic factors important to the successful commercialisation of an SC-CO2 polyester yarn package dyeing process. 34 refs. USA

Accession no.839799 Item 180 Polymer Preprints. Volume 41. Number 2. Conference proceedings. Washington, D.C., 20th-24th Aug.2000, p.1838-9 PATTERNABLE LOW-K DIELECTRICS DEVELOPED USING SUPERCRITICAL CO2 Weibel G L; Pryce-Lewis H-G; Gleason K K; Ober C K’ Cornell University; Massachusetts,Institute of Technology (ACS,Div.of Polymer Chemistry) Processing used in microelectronics is increasingly designed with environmental impact in mind. As technologies change, new process insertion points occur. The role of polymers in microelectronics has traditionally been conÀned to photoresist materials, but is expanding to include low dielectric constant (low-k) materials. A collaboration is presented, intended to merge the role of resist and dielectric material, resulting in directly-patterned low-k Àlms. These patterned Àlms serve as insulating material compatible with metallisation schemes including the damascene process. In examining this all-dry process that involves CVD deposition and supercritical CO2 pattern development, it is shown that it may be possible to eliminate the multiple steps presently required in current manufacturing for generating patterned insulators. A new processing tool, supercritical CO2, has gained increasing interest as a developer, drying solvent and cleaning agent in

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efforts to capitalise on the unique properties of supercritical Áuids (SCF). SCF CO2 has high diffusivity comparable to gas, has negligible surface tension and has density near that of a liquid that can be tuned by minor temperature and pressure adjustments. SCF CO2 is found to be suitable as a developer for CVD Áuorocarbon systems, as well as for Áuorinated resists patterned with small and high aspect ratio features that may otherwise experience pattern collapse due to surface tension from aqueous developers. Positive-tone contrast is demonstrated in Áuorocarbon CVD Àlms by 1.0 mu m line and space features patterned from e-beam exposure. Investigations of polymer and CVD Àlm solubility/dissolution and minimum achievable feature sizes are discussed. 12 refs. USA

Accession no.839742 Item 181 Polymer Preprints. Volume 41. Number 2. Conference proceedings. Washington, D.C., 20th-24th Aug.2000, p.1817 CO2 TECHNOLOGY PLATFORM FOR SUSTAINABLE MANUFACTURING DeSimone J North Carolina,University; North Carolina,State University (ACS,Div.of Polymer Chemistry) Regulations on the release of toxic chemicals to the environment have steadily increased over the years. Organic or halogenated solvents account worldwide for more than 30 billion lb of solvent usage each year. Manufacturing and service industries are faced with the dilemma of avoiding the production, use and subsequent release of contaminated water, volatile organic solvents, chlorofluorocarbons and other noxious solvents and contaminants into the environment. The need to develop a more environmentally responsible and energy efÀcient solvent technology platform is paramount and the leading candidate is liquid and supercritical carbon dioxide. 4 refs. USA

Accession no.839731 Item 182 ACS POLYMERIC MATERIALS SCIENCE AND ENGINEERING. SPRING MEETING 2001. VOLUME 84. Proceedings of a conference in San Diego, Ca.. Washington, D.C., 2001, p.138. 012 SUPERCRITICAL FLUID-ASSISTED SYNTHESIS AND PROCESSING OF POLYMERIC MATERIALS: KINETIC AND THERMODYNAMIC CONSIDERATIONS Watkins J J; Brown G; Gupta R; Ortelli D; Ramachandra Rao V; Vogt B Massachusetts,University Case studies are presented which describe the preparation of precisely ordered nanocomposites and reactive blending in

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References and Abstracts

the presence of carbon dioxide. It was demonstrated that in multi-component polymer systems, carbon dioxide sorption not only inÁuences molecular mobility, but also has a very signiÀcant effect on polymer/polymer compatibility. The phase behaviour of polymer blends and block copolymers in the presence of carbon dioxide was determined using complimentary techniques including in situ small angle neutron scattering, high pressure Áuorescence spectroscopy, and measurements of optical birefringence. Results suggest that near upper critical solution transitions, carbon dioxide sorption can promote polymer miscibility through intersegment screening in analogy with liquid diluents, but near lower critical sorption transitions, sorption of carbon dioxide can induce phase segregation at temperatures hundreds of degrees below the ambient pressure transition. In all instances, the location of the transitions can be tuned over broad-ranges through pressure-mediated adjustments in solvent density. Small molecule diffusion in carbon dioxidedilated polymers using in situ Áuorescence non-radiative energy transfer techniques are also reported. The results indicate enhancement in probe diffusivities that exceed Àve orders of magnitude upon sorption of carbon dioxide in polystyrene. USA

Accession no.839631 Item 183 ACS POLYMERIC MATERIALS SCIENCE AND ENGINEERING. SPRING MEETING 2001. VOLUME 84. Proceedings of a conference in San Diego, Ca.. Washington, D.C., 2001, p.134-5. 012 INTERFACE STUDIES ON SUPERCRITICAL CO2 WELDED SEMI-CRYSTALLINE POLYMERS Caskey T C; Lesser A J; McCarthy T Massachusetts,University Studies were carried out on the interface of supercritical carbon dioxide welded semi-crystalline linear low density polyethylene (LLDPE) polymer films in order to more completely describe the mechanisms of adhesion. The samples were tested in a T-Peel geometry to determine the strength of adhesion. The integrity of the weld line was analysed using atomic force microscopy and optical microscopy. The morphological nature of the interface region was characterised using transmission electron microscopy and scanning electron microscopy. The interfaces were demonstrated to be seamless and to have good physical integrity. The interface is highly amorphous, as revealed by transmission electron microscopy and etching results. Adhesion was attained at temperatures below the melting temperature which allows the retention of the original morphology and crystal structure after processing, as revealed by differential scanning calorimetry and wide angle X-ray scattering. It is evident that the most consistent mechanism of adhesion is amorphous diffusion of chains across the interface. 5 refs.

Item 184 ACS POLYMERIC MATERIALS SCIENCE AND ENGINEERING. SPRING MEETING 2001. VOLUME 84. Proceedings of a conference in San Diego, Ca.. Washington, D.C., 2001, p.125-6. 012 SYNTHESIS OF MACROPOROUS POLYMER BEADS BY SUSPENSION POLYMERIZATION USING SUPERCRITICAL CARBON DIOXIDE AS A PRESSURE-ADJUSTABLE POROGEN Wood C D; Cooper A I Liverpool,University Investigations were carried out into the possibility of preparing macroporous polymer beads by oil-inwater suspension polymerisation using supercritical carbon dioxide as the porogenic solvent. Suspension polymerisation of trimethylol propane trimethacrylate was carried out under various conditions. Polymer morphology was studied using scanning electron microscopy. Nitrogen adsorption/desorption and mercury intrusion porosimetry results were also obtained. It was demonstrated that welldeÀned macroporous polymer beads can be synthesised in the absence of any organic solvents using supercritical carbon dioxide as the porogen. It is possible that these initial results are the most signiÀcant yet of a system where polymer properties can be tuned by varying the supercritical Áuid solvent density. 11 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.839624 Item 185 Polymer Engineering and Science 41, No.12, Dec. 2001, p.2259-65 SUPERCRITICAL CO2 WELDING OF LAMINATED LINEAR LOW DENSITY POLYETHYLENE FILMS Caskey T; Lesser A J; McCarthy T J Massachusetts,University Supercritical carbon dioxide was used as a reversible plasticising agent to promote solvent welding of quasiisotropic, highly oriented laminated LLDPE films. The interfacial adhesion between individual plies, morphological properties, crystal structure, tensile properties, puncture resistance and tear resistance of the laminated Àlms were investigated and the data obtained compared with those for unoriented LLDPE Àlms. 15 refs. USA

Accession no.839391

USA

Accession no.839628

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Item 186 Industrial and Engineering Chemistry Research 40, No.23, 14th Nov. 2001, p.5570-7 PROCESSING OF POLYAMIDE 11 WITH SUPERCRITICAL CARBON DIOXIDE Martinache J D; Royer J R; Siripurapu S; Henon F E; Genzer J; Khan S A; Carbonell R G North Carolina,State University; AtoÀna Chemicals Inc. The supercritical carbon dioxide induced swelling and plasticisation of polyamide 11 were investigated. The diffusion coefficient of carbon dioxide in polyamide 11 was calculated from the initial slope of the swelling kinetics data. The use of carbon dioxide as a blowing agent was also investigated and preliminary foaming attempts using a batch process are reported. 52 refs. USA

Accession no.838726 Item 187 Synthetic Metals 123, No.3, 24th Sept.2001, p.509-14 SYNTHESIS OF CONDUCTIVE ELASTOMERIC FOAMS BY AN IN SITU POLYMERIZATION OF PYRROLE USING SUPERCRITICAL CARBON DIOXIDE AND ETHANOL COSOLVENTS Shenoy S L; Kaya I; Erkey C; Weiss R A Connecticut,University Conductive polyurethane/polypyrrole composite foams were prepared using supercritical carbon dioxide to impregnate a polyurethane foam with ferric triÁuoromethane sulphonate or ferric triÁuoroacetate, followed by in situ polymerisation of pyrrole. A small amount of ethanol was added to the supercritical carbon dioxide and this greatly improved the solubility of the oxidants in the supercritical carbon dioxide. The conductivity of the composite foams was 0.0000001- 0.01 S/cm depending on how much ethanol was used and the impregnation time. The amount of polypyrrole formed depended on the amount of oxidant absorbed by the foam. When low ethanol concentrations and/or short impregnation times were used, the polypyrrole produced was concentrated at or near the surfaces of the foam sample. By increasing the amount of ethanol and the impregnation time the dispersion of the polypyrrole in the foam was improved. The use of the ferric triÁuoroacetate resulted in foams with much lower conductivity than those using triÁuoromethane sulphonate. The electrically conductive polymers formed have uses in technologies, such as rechargeable batteries, sensors, EMI shielding and biomaterials. 19 refs. USA

Accession no.836773 Item 188 Polymer Engineering 1, No.8, Nov.2001, p.24-5 FARADAY PORTABLE INJECTION MOULDER

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In response to signiÀcant industrial interest in liquid and supercritical CO2 as a ‘green solvent’ and processing aid, a demonstration unit has been developed to exploit the technology for in-situ plasticisation and foaming of plastics. This development is part of a Faraday Plastics project, in collaboration with Rapra Technology. This fully automated, user-friendly machine is believed to be the world’s Àrst portable injection moulding machine to incorporate supercritical CO2 foaming technology. The gas-injection facility can be used as a foaming agent or as a means to lower the viscosity of the melt in order to case Áow and improve product quality. Rapra had taken a standard bench-top injection moulder from MCP Equipment of Stone, Staffordshire, in order to carry out the conversion. MCP was chosen as a partner for this project as the company manufactures a range of mini-moulding and blow moulding machines ideal for R & D work due to their small footprint and portability. Details are given. FARADAY PLASTICS; MCP EQUIPMENT LTD.; RAPRA TECHNOLOGY LTD. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.835596 Item 189 Nippon Gomu Kyokaishi 74, No.5, May 2001, p.173-8 Japanese CHEMICAL RECYCLING PROCESS FOR WASTE PLASTICS USING SUPER-CRITICAL WATER Fukuzato R The reaction-catalysing properties of super-critical Áuids are described, and some examples are demonstrated of the chemical recycling of waste plastics. 16 refs. Articles from this journal can be requested for translation by subscribers to the Rapra produced International Polymer Science and Technology. Accession no.834123 Item 190 Macromolecular Chemistry and Physics 202, No.14, 28th Sept. 2001, p.2857-63 FREE-RADICAL POLYMERIZATIONS OF STYRENE IN CO2/ETHANOL MIXED SUPERCRITICAL FLUID Mingotaud A-F; Begue G; Cansell F; Gnanou Y CNRS The free radical polymerisation of styrene was studied in carbon dioxide/ethanol mixed supercritical Áuid. Results were compared with those generated in the presence of mesitylene or pure ethanol used as solvent. 29 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; WESTERN EUROPE

Accession no.833958

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References and Abstracts

Item 191 Polymer Science Series B 43, Nos.7-8, July/Aug.2001, p.227-9 SYNTHESIS OF POLYIMIDES IN SUPERCRITICAL CARBON DIOXIDE Said A-Galiev E E; Vygodskii Y S; Nikitin L N; Vinokur R A; Gallyamov M O; Khokhlov A R Russian Academy of Sciences Polyimides with a quantitative yield are produced by the polycyclocondensation of dianhydride 6F, diamine 6F and 9,9-bis(4’-aminophenyl)Áuorene in supercritical carbon dioxide (32.5 MPa, 180 deg.C). The synthesised polymers have an inherent viscosity up to 0.43 dl/g, Mw = 12.4 x 10 3, Mn = 4.7 x 10 3 and Mw/Mn = 2.6. It is suggested that, in the presence of traces of water, supercritical carbon dioxide plays the role of a catalyst in the formation of polyimides. 4 refs. RUSSIA

Accession no.831630 Item 192 Plast’ 21 No.102, May 2001, p.32-4 Spanish MORE ECONOMICAL GAS INJECTION MOULDING The MuCell process developed by Husky for injection moulding microcellular plastics and thermoplastic elastomer foam components is described. The advantages of this process, which uses supercritical Áuids of nitrogen or carbon dioxide as blowing agents, are examined in comparison with conventional gas injection moulding techniques. HUSKY INJECTION MOULDING SYSTEMS LTD.; TREXEL CANADA; USA

Accession no.831352 Item 193 Revista de Plasticos Modernos 81, No.535, Jan.2001, p.92-8 Spanish USE OF SUPERCRITICAL FLUID TECHNOLOGY IN THE PREPARATION OF SYSTEMS FOR THE CONTROLLED RELEASE OF DRUGS Fanovich M A; Fraile J; San Roman J; Rodriguez-Clemente R; Domingo C Barcelona,Institut de Ciencia de Materials; Instituto de Ciencia y Tecnologia de Polimeros

are classiÀed as a function of the solubility of polymers and drugs in the solvent. 50 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; SPAIN; WESTERN EUROPE

Accession no.831307 Item 194 Industrial and Engineering Chemistry Research 40, No.19, 19th Sept. 2001, p.4058-68 COATING OF METAL POWDERS WITH POLYMERS IN SUPERCRITICAL CARBON DIOXIDE Glebov E M; Yuan L; Krishtopa L G; Usov O M; Krasnoperov L N New Jersey,Institute of Technology Supercritical carbon dioxide was used as a solvent to produce PVDF and polyvinyl biphenyl Àlms on fused silica plates and metal powders. Protective properties of the Àlms were quantiÀed based on the dissolution rate. The average thickness of the Àlms was evaluated using UV absorption spectroscopy. A technique to measure the solubilities of poorly soluble polymers in supercritical carbon dioxide was developed. 47 refs. USA

Accession no.831141 Item 195 Journal of Biomedical Materials Research (Applied Biomaterials) 58, No.5, 2001, p.505-10 ASSESSMENT OF PARAMETERS ASSOCIATED TO THE RISK OF PVC CATHETER REUSE Granados D L; Jimenez A; Cuadrado T R San Juan,National University; Alicante,University; Mar del Plata,Universidad Nacional Details are given of the identiÀcation of material parameters that could contribute to the health risks associated with the practice of reprocessing PVC catheters. supercritical Áuid extraction was used to determine the total percentage of extractables and off-line gas chromatography-Áame ionisation detection was used for the identiÀcation and quantiÀcation of bisethylhexyl phthalate. Data are also presented for Tg, storage modulus, dissipation factor, and surface roughness. 24 refs. ARGENTINA; EUROPEAN COMMUNITY; EUROPEAN UNION; SPAIN; WESTERN EUROPE

Accession no.831095

The basic concepts of supercritical Áuid technology are examined, and the use of supercritical carbon dioxide as a solvent in processes for the preparation of polymeric microcapsules and microspheres for controlled drug release is discussed. The different preparation processes

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Item 196 Antec 2001.Conference proceedings. Dallas, Texas, 6th-10th May, 2001, paper 670 COMMERCIALIZATION OF MICROCELLULAR BLOW MOLDING Straff R; Anderson J; Blizard K; Chapman B Trexel Inc. (SPE) Microcellular blow moulding is brieÁy discussed. It is proposed that the technology may be used to reduce bottle weight whilst maintaining other important performance characteristics. The process involves the injection of a precise amount of supercritical Áuid blowing agent into the extruder, forming a single phase solution with the polymer melt. Nucleation is initiated by a rapid pressure drop followed by expansion of the cells, the size of which is controlled by controlling the process conditions. The Ànal stage is the shaping of the part. Process technology has been developed, including extruder screw design, Áuid injectors and metering systems, and die design to control cell nucleation. Conventional moulding techniques are used. USA

Accession no.830102 Item 197 Journal of Applied Polymer Science 81, No.9, 29th August 2001, p.2102-8 DEPOLYMERIZATION OF POLYETHYLEN ETEREPHTHALATE IN SUPERCRITICAL METHANOL Kim B-K; Hwang G-C; Bae S-Y; Yi S-C; Kumazawa H Hanyang,University The depolymerisation of PETP in supercritical methanol was caried out using a batch-type autoclave reactor. The conversion and yield of dimethyl terephthalate (DMT) increased with rising temperature. The yield of DMT exceeded 50% above 280C and the Ànal yield of DMT at 300 and 310C reached 97.0% and 97.7% respectively. the yield of ethylene glycol was slightly lower than that of DMT. the yield of DMT increased markedly when the methanol density was 0.08 g/cc and levelled off at higher densities. A kinetic model to simulate the depolymerisation of PETP in supercritical methanol was suggested. The values of the forward reaction rate constants at different temperatures were determined by comparing the observed time dependence with that calculated by the proposed model. The activation energy was found to be 49.9 kJ/mol, which was close to a previously published value of 55.7 kJ/mol. 4 refs. KOREA

Accession no.828757 Item 198 Advanced Materials 13, No.14, 18th July 2001, p.1111-4

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RECENT DEVELOPMENTS IN MATERIALS SYNTHESIS AND PROCESSING USING SUPERCRITICAL CO2 Cooper A I Liverpool,University Some recent studies involving the use of supercritical carbon dioxide, as a solvent, in the synthesis and processing of various advanced materials, including porous organic materials, coatings, lithographic resists, metal nanoparticles and biomaterials, are reviewed. 16 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.826341 Item 199 Antec 2001.Conference proceedings. Dallas, Texas, 6th-10th May, 2001, paper 331 SUPERCRITICAL CARBON DIOXIDE ASSISTED POLYMER BLENDING IN TWINSCREW EXTRUSION: PHASE INVERSION, MORPHOLOGY, AND MECHANICAL PROPERTIES Elkovitch M D; Lee L J; Tomasko D L Ohio,State University (SPE) The inÁuence of supercritical carbon dioxide additions during the twin-screw extrusion blending of polystyrene (PS) with poly(ethylene-co-methyl acrylate) impact modiÀer, and of poly(methyl methacrylate) (PMMA) with the impact modiÀer, was investigated. Phase inversion, morphology and mechanical properties were studied for a CO2 addition of 2.0 wt%. The CO2 increased the phase inversion rate by reducing the glass transition temperatures of PS and PMMA. The increased inversion rate, in conjunction with a reduced viscosity ratio, led to enhanced dispersion of the impact modiÀer phase. The use of CO2 gave an increase in impact strength and a reduction in the Áexural modulus, indicating the enhanced dispersion of the rubber impact modiÀer phase into the brittle polymer matrices. The morphology was not changed by reprocessing. 17 refs. USA

Accession no.825955 Item 200 Journal of Macromolecular Science B 40, No.2, 2001, p.189-97 DYEING BEHAVIOR OF HIGH-SPEED SPUN POLY(ETHYLENE TEREPHTHALATE) FIBERS IN SUPERCRITICAL CARBON DIOXIDE Kawahara Y; Yoshioka T; Sugiura K; Ogawa S; Kikutani T Kyoto,Institute of Technology; Kyoto,Municipal Textile Research Institute; Tokyo,Institute of Technology The dyeing behaviour of several types of high-speed and normal speed spun PETP Àbres was compared in

© Copyright 2005 Rapra Technology Limited

References and Abstracts

supercritical carbon dioxide Áuid. At lower temp. and pressure, the high-speed spun Àbres, which had inherently larger crystallite sizes and lower birefringence, showed a larger dye uptake than the other fibres. When the supercritical conditions were elevated to 125C and 230 bar, the dye uptake of both types increased markedly and the difference in dye uptake between the fibres became small. This indicated that the swelling of Àbres in supercritical carbon dioxide Áuid exceeded a certain level and the diffusion of dye molecules was then promoted. The swelling also promoted the rearrangement of molecular chains and permitted cold crystallisation to occur. The modiÀcation of Àbre structure through dyeing in supercritical carbon dioxide fluid was significant, particularly for the Àbres whose inherent structure was not so well developed. 20 refs. JAPAN

Accession no.825008 Item 201 Antec 2001.Conference proceedings. Dallas, Texas, 6th-10th May, 2001, paper 200 SUPERCRITICAL FLUID ASSISTED POLYMER PROCESSING Matthews S O; Hornsby P R Brunel University (SPE) A single screw extruder with a direct injection port for supercritical carbon dioxide was used to study the inÁuence of CO2 additions on the processing of polyethylene (PE) and PE containing silicon nitride. The extruder was Àtted with a slit die for in-line rheometry. The injection of CO2 gave an average reduction in viscosity of 25%. Negligible foaming was observed, and was dependent upon screw speed, temperature, and the rate of CO2 injection and pressure. Removal of the PE from the composite materials by thermal treatment yielded ceramics of controlled porosity which could be successfully sintered. 8 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.823412 Item 202 Antec 2001.Conference proceedings. Dallas, Texas, 6th-10th May, 2001, paper 199 MEASUREMENT OF ENTRANCE PRESSURE DROP OF POLYSTYRENE/SUPERCRITICAL CO2 SOLUTIONS Xue A; Tzoganakis C Waterloo,University (SPE) The inÁuence of pressure and supercritical carbon dioxide content on the entrance pressure drop and rheological properties of polystyrene/CO2 solutions was investigated using a twin screw extruder Àtted with 180 degree entrance angle slit dies with contraction ratios of 4:1 and 18:1.

© Copyright 2005 Rapra Technology Limited

Pressure was measured using transducers before and after the die contraction. The introduction of CO2 into the polystyrene melt reduced the entrance pressure drop, and the shear and extensional viscosities. The entrance pressure drops as a function of wall shear stress Àtted a master curve for different CO2 contents and pressure levels. 10 refs. CANADA

Accession no.823411 Item 203 Blowing Agents ‘99. Proceedings of a conference held at the conference centre UMIST, UK, 9th.-10th December 1999.. Shawbury, 1999, Paper 11, p.59-63. 012 MICROCELLULAR FOAM MOLDING TECHNOLOGY Pierick D; Janisch R Trexel Inc. (Rapra Technology Ltd.) The MuCell foam moulding technology, invented by the Massachusetts Institute of Technology’s Mechanical Engineering Department, and licenced exclusively by Trexel Inc., is described. The proprietary process uses supercritical Áuids of atmospheric gases to create evenly distributed and uniformly sized microscopic cells throughout a polymer. The process is suitable for injection moulding, blow moulding and extrusion, providing advantages in product design, processing efÀciency and cost reduction. The use of MuCell technology permits moulders to reduce raw material consumption and cycle time whilst producing strong, lighter weight products, the ability to foam thin-walled parts, reduce processing temperatures, injection pressure and clamp tonnage. In addition, the process enables moulders to foam materials that previously could not be foamed successfully using conventional foaming technologies, such as high temperature polysulphone, polyetherimide, liquid crystalline polymers and thermoplastic elastomers. These advantages and features of the MuCell technology are further discussed, and examples of applications are described. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; USA; WESTERN EUROPE

Accession no.818864 Item 204 Blowing Agents ‘99. Proceedings of a conference held at the conference centre UMIST, UK, 9th.-10th December 1999.. Shawbury, 1999, Paper 10, p.53-57. 012 CARBON DIOXIDE AS BLOWING AGENT IN THE EXTRUSION OF THERMOPLASTIC FOAMS Gale M Rapra Technology Ltd. (Rapra Technology Ltd.) The use is discussed of carbon dioxide as a blowing agent in the extrusion of thermoplastic foams, in particular,

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polyoleÀns and polystyrene. The paper summarises some of the work carried out at Rapra Technology Ltd., into the use of carbon dioxide with a conventional single screw extruder, retroÀtted with a Cavity Transfer Mixer and a static mixer heat exchanger. Estimates are included of potential cost savings for a proposed commercial applications, and an indication of the type of equipment which will probably be used. 9 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.818863 Item 205 Industrial and Engineering Chemistry Research 40, No.3, 7th Feb.2001, p.756-67 DEPOLYMERISATION OF STYRENEBUTADIENE COPOLYMER IN NEAR-CRITICAL AND SUPERCRITICAL WATER Park Y; Hool J N; Curtis C W; Roberts C B Auburn,University Many conventional solvents do not sufÀciently dissolve crosslinked polymers such as SBR to allow efÀcient polymerisation. Supercritical and near-critical water provides an alternative benign solvent for this application. Supercritical water oxidation and thermal gradation under supercritical water conditions provide a means to break down rubbery materials into organic compounds that can then be recovered as a chemical feedstock. Depolymerisation reactions of SBR are examined in a semi-continuous reactor. A statistical experimental analysis technique is used to investigate the effect of various operating conditions: temperature, pressure and the presence of hydrogen peroxide as an oxidant. The results demonstrate the ability of supercritical and near-critical water to break down the SBR into a range lower molecular weight organic compounds for potential recovery. Analysis of variance shows that the temperature and oxidant concentration are signiÀcant at the 1% level for destruction efficiency. Benzene, toluene, ethylbenzene, styrene, phenol, acetophenone, benzaldehyde and benzoic acid are identiÀed as liquid products using gas chromatography in both and semi-continuous reactors. The gas products are comprised of carbon monoxide, carbon dioxide and water as determined by Fourier transform IR spectroscopy. The efÀciency and a semi-quantitative analysis of the liquid products show that both pyrolysis and oxidation products are observed, and low molecular weight oxidation products are to be primary. 7 refs. USA

Accession no.810172 Item 206 Polymer Science Series C 42, No.1, 2000, p.78-101 POLYMER PROCESSING WITH SUPERCRITICAL FLUIDS Kararian S G

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London,Imperial College of Science,Technology & Medicine Supercritical Áuids have a unique and valuable potential for the enhanced processing of many materials. Research in the applications of supercritical fluids to polymer processing are reviewed. The ability of supercritical carbon dioxide to swell and plasticise polymers is crucial to impregnation, extraction and modiÀcation of polymeric materials. This plasticisation also reduces viscosity and facilitates the processing of polymers due to lower shear stresses. Spectroscopy plays an important role in probing these interactions at a molecular level and to follow in situ the processes of CO2-induced plasticisation and the crystallisation of polymers. Opportunities exist for improving the processing of many polymeric-based materials ranging from textile to food and biomaterials. The implications of interactions between supercritical carbon dioxide and polymers for drying, dyeing, foaming and extrusion are also discussed with an outlook for further opportunities in this and related areas of polymer processing. 312 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.809650 Item 207 Macromolecules 34, No.4, 13th Feb.2001, p.775-81 RING-OPENING POLYMERIZATION OF EPSILON-CAPROLACTONE IN SUPERCRITICAL CARBON DIOXIDE Stasssin F; Halleux O; Jerome R Liege,University The ring-opening polymerisation of epsilon-caprolactone was investigated in supercritical carbon dioxide at 40 C and 210-215 bar, with dibutyltin dimethoxide initiator. The polymer molecular weight was dependent upon the monomer:tin alkoxide molar ratio and the degree of monomer conversion. First-order reaction kinetics were observed, the kinetics being lower than for polymerisation in toluene and in bulk. This was attributed to the competitive coordination of CO2 onto tin. 21 refs. BELGIUM; EUROPEAN COMMUNITY; EUROPEAN UNION; WESTERN EUROPE

Accession no.808638 Item 208 Polymer Engineering and Science 41, No.2, Feb.2001, p.135-44 DRAWING IN HIGH PRESSURE CARBON DIOXIDE - A NEW ROUTE TO HIGH PERFORMANCE FIBERS Hobbs T; Lesser A J Massachusetts,University A new draw technique for polymer orientation was developed and applied to different polymer Àbres (PETP,

© Copyright 2005 Rapra Technology Limited

References and Abstracts

nylon-66 and UHMWPE). In this technique, a polymer was drawn uniaxially in supercritical carbon dioxide using a custom high-pressure apparatus. This technique could be used as a replacement for the traditional drawing process or as a post-treatment process. With PETP, the technique was not effective at temps. at or below 130C. In contrast, the process was highly effective for nylon-66, where carbon dioxide drawn Àbres showed signiÀcantly higher crystallinity and orientation, together with improved mechanical properties. While the Àbres were plasticised, the drawability of the Àbres was only slightly dependent on temp. High pressure carbon dioxide drawing of UHMWPE fibres was equally effective. Commercial high performance Àbres could be drawn up to a ratio of 1.9 in a second stage, resulting in large increases in tensile modulus and small improvements in TS. 40 refs. USA

Accession no.807502 Item 209 Journal of the Textile Institute - Part 3: Textile Design: Technology, Management and Marketing Vol.91, 2000, p.166-7 NOTES ON FUTURE DEVELOPMENTS FOR TEXTILE FINISHING PROCESSES Knittel D; Schollmeyer E German Textile Research Institute North-West eV A brief description is presented of textile Ànishing processes that are liable to gain broad technical application in the near future and on other processes that require intensive research work but promise beneÀcial new ecological and economical treatment procedures. The processes discussed include supercritical Áuid dyeing of synthetic Àbres (particularly PETP), electric dyeing, liquid ammonia treatment of cellulosic Àbres, enzymatic processes, and processes for conductive Àbres, liquid crystal Àbres and Àbres derived from new bioresources. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.807440 Item 210 Chemical and Engineering News 79, No.5, 29th Jan.2001, p.34-5 ONE STEP TO BIOACTIVE POLYMERS Brennan M B A report is presented on studies led by S.M.Howdle at the University of Nottingham in which supercritical carbon dioxide is used to incorporate inorganic materials and enzymes into the biodegradable polymers poly(lactideco-glycolide) and poly(DL-lactide). Particular attention is paid to the incorporation of hydroxyapatite in order to create artiÀcial bone and to the incorporation of catalase, ribonuclease A and beta-D-galactosidase. NOTTINGHAM,UNIVERSITY

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EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.807333 Item 211 Industrial and Engineering Chemistry Research 40, No.2, 24th Jan.2001, p.536-43 LATEXES FORMED BY RAPID EXPANSION OF POLYMER/CARBON DIOXIDE SUSPENSIONS INTO WATER. I. HYDROPHILIC SURFACTANT IN SUPERCRITICAL CARBON DIOXIDE Jae-Jin Shim; Yates M Z; Johnston K P Texas,University The rapid expansion of poly-2-ethylhexyl acrylate suspensions in supercritical carbon dioxide containing a hydrophilic as well as a carbon dioxide-philic surfactant produced stable aqueous latices. The hydrophilic surfactants were soluble in both carbon dioxide and water. The aqueous latices could also be formed after depressurisation and resuspension of the polymer dispersion in carbon dioxide. Latices in basic buffer solutions were stable for a few weeks for concentrations up to 15.6% and for several months after sonication. The synthesis of water-dispersible polymer particles in carbon dioxide, which could be transferred to water without the need for organic solvents, could be used for preparation of new environmentally-benign coatings and adhesives. 28 refs. USA

Accession no.807153 Item 212 Journal of Polymer Research 7, No.3, Sept.2000, p.155-9 ANALYSIS ON THE DYEING OF POLYPROPYLENE FIBERS IN SUPERCRITICAL CARBON DIOXIDE Liao S K; Chang P S; Lin Y C Feng Chia,University PP Àbres were dyed in a supercritical carbon dioxide system and the results were compared with those for Àbres dyed in water system. Dye uptake value calculated by UV spectroscopy indicated that PP Àbre dyeing was much better in carbon dioxide than in water. Optical microscopic analysis showed that dye molecules had diffused thoroughly into Àbre in carbon dioxide because of the good compatibility between the dye and the carbon dioxide. X-ray and birefringence analysis demonstrated that plasticisation caused by the introduction of carbon dioxide made the molecular chain more mobile and led to an increase in the dyeing of PP Àbres. Furthermore, a mechanical test and DSC analysis indicated that the Àbre structure was not damaged when the fabric was dyed at 100C. 23 refs. TAIWAN

Accession no.807128

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Item 213 Macromolecules 33, No.25, 12th Dec.2000, p.9222-7 FREE RADICAL POLYMERIZATION OF METHYL METHACRYLATE IN SUPERCRITICAL CARBON DIOXIDE USING A PSEUDO-GRAFT STABILIZER: EFFECT OF MONOMER, INITIATOR, AND STABILIZER CONCENTRATIONS Christian P; Giles M R; GrifÀths R M T; Irvine D J; Major R C; Howdle S M Nottingham,University; Uniqema The free radical polymerisation of methyl methacrylate in supercritical carbon dioxide was described, using a commercially available acid-terminated perÁuoropolyether as a polymerisation stabiliser. The effects of varying the concentrations of monomer, stabiliser and initiator (AIBN) on the molecular weight, yield and morphology of the resulting PMMA were studied. Unusual morphologies occurred at high initiator concentration and low stabiliser concentration. Remarkably high polymer yields were produced even at very low stabiliser concentrations. No detectable stabiliser residues were found in the PMMA, even when very high stabiliser concentrations were used. 24 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.803578 Item 214 ACS Polymeric Materials Science and Engineering. Volume 75. Conference Proceedings. Orlando, FL., Fall 1996, p.73. 012 SUPERCRITICAL FLUID IMPREGNATION OF DYE INTO GLASSY POLYMERS Kazarian S G; Brantley N H; Vincent M F; West B L; Liotta C L; Eckert C A Georgia,Institute of Technology (ACS,Div.of Polymeric Materials Science & Engng.) It is known that supercritical carbon dioxide (scCO2) can be used to swell and plasticise glassy polymers for solventfree incorporation of additives. For example, although Disperse Red 1 dye (DR1) is relatively insoluble in scCO2, the high partition coefÀcient in scCO2 has enabled incorporation of about 3 weight percent into a PMMA matrix. This is likely to be attributable to hydrogen bonding between the hydroxyl moiety of DR1 and the carbonyl groups of PMMA. The enhanced diffusion process was observed in situ using FTIR and UV/vis spectroscopy. Among the other applications of tunable, solvent-free scCO2 impregnation into glassy polymers might be dyeing processes or non-linear optical materials. USA

Accession no.803056

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Item 215 Journal of Polymer Science: Polymer Physics Edition 38, No.23, 1st Dec.2000, p.3168-80 HIGH-PRESSURE RHEOLOGY OF POLYSTYRENE MELTS PLASTICISED WITH CO2: EXPERIMENTAL MEASUREMENT AND PREDICTIVE SCALING RELATIONSHIPS Royer J R; Gay Y J; Desimone J M; Khan S A North Carolina,State University A high-pressure extrusion slit die rheometer is constructed to measure the viscosity of polymer melts by liquid and supercritical CO2. A novel gas injection system is devised to accurately meter the follow of CO2 into the extruder barrel. Measurements of pressure drop, within the die, conÀrm the presence of a one-phase mixture and a fully-developed Áow during viscosity measurements. Experimental measurements of viscosity as a function of shear rate, pressure, temperature and CO2 concentration are conducted for three commercial PS melts. The CO2 is shown to be an effective plasticiser for PS, lowering the viscosity of the polymer melt by as much as 80%, depending of the process conditions and CO2 concentration. Existing theories for viscoelastic scaling of polymer melts and the prediction of Tg depression by a diluent are used to develop a free volume model for predicting the effects of CO2 concentration and pressure on polymer melt rheology. The free volume model, dependent only on material parameters of the polymer melt and pure CO2, is shown to accurately collapse the experimental data onto a single master curve independent of pressure CO2 concentration for each of the three PS a samples. This model constitutes simple predictive set of equations to quantify the effects of gas-induced plasticisation on molten polymer systems. 47 refs. USA

Accession no.802457 Item 216 ACS Polymeric Materials: Science and Engineering. Fall Meeting 2000. Volume 83. Washington, D.C., 20th-24th Aug.2000, p.538-9 CHEMICALLY SENSITIVE NANOPARTICLES DEVELOPED FROM RAPID EXPANSION OF SUPERCRITICAL SOLUTIONS Pestov D; Levit N; Colby D; Tepper G Virginia,Commonwealth University (ACS,Div.of Polymeric Materials Science & Engng.) Rapid expansion of supercritical solutions (RESS) is a versatile technique capable of particle size tuning over a range of 4-5 orders of magnitude. It takes advantage of the enormous solubility change that occurs by rapidly expanding a supercritical solution through a restriction (small oriÀce or capillary nozzle) in order to form precipitates with narrow and tunable size distributions. Silicone polymers are attractive for chemical sensor applications because of their favourable physical and chemical properties as well as the possibility for chemical modiÀcation. The most

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References and Abstracts

interesting family of silicone polymers are the silicone rubbers - ready for curing compounds, that overcome the poor mechanical properties of raw silicones after intermolecular net formation. Siloxane based polymers are known to be soluble in supercritical carbon dioxide over a wide range of concentrations. The main disadvantage of raw siloxanes in sensor applications is the loss of surface integrity over time due to inadequate viscosity. A new approach is described combining RESS and room temperature gas-phase curing to produce siloxane based, chemically active and physically stable polymer particles with a wide range of morphologies. 5 refs. USA

Accession no.802377 Item 217 Antec 2000.Conference proceedings. Orlando, Fl., 7th-11th May, 2000, paper 488 SUPERCRITICAL CARBON DIOXIDE ASSISTED POLYMER BLENDING IN TWIN-SCREW EXTRUSION: RELATIONS BETWEEN MORPHOLOGY EVOLUTION AND MECHANICAL PROPERTIES Elkovitch M D; Lee L J; Tomasko D L Ohio,State University (SPE) The inÁuence of additions of 0.5-3.0 wt% of supercritical carbon dioxide to blends of polystyrene (PS) and poly(methyl methacrylate) (PMMA) was investigated during compounding using a twin screw extruder. Viscosity reductions of up to 80% and 70% were observed for PMMA and PS, respectively. The dispersed phase exhibited a sharp decrease in size adjacent to the injection point, but further compounding resulted in its coalescence, and demixing occurred when the CO2 was vented. The Ànal morphology was similar to that observed without the addition of CO2. Small additions of Àllers slowed down the demixing on release of the CO2. 12 refs. USA

Accession no.802018 Item 218 Popular Plastics and Packaging 46, No.1, Jan. 2001, p.77-9 REVIEW ON THE APPLICATIONS OF SUPERCRITICAL FLUIDS IN POLYMER PROCESSING Tipnis S J The use of supercritical Áuids and in particular supercritical carbon dioxide is examined with respect to the beneÀts it provides in polymer processing and polymerisation. The viability of using supercritical carbon dioxide as a solvent medium for homogeneous solution of polymerisation in place of ecologically dangerous solvents such as CFC was demonstrated in the homogeneous synthesis of Áuorinated telomers. A further development in the use

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of supercritical carbon dioxide is in the direct formation of microcellular thermoplastic parts, in which the direct addition of supercritical Áuid is done in an extruder to produce foamed plastic parts. 6 refs. INDIA

Accession no.801405 Item 219 Industrial and Engineering Chemistry Research 39, No.12, Dec.2000, p.4891-6 NEW CHELATE COMPLEXES OF COPPER AND IRON: SYNTHESIS AND IMPREGNATION INTO A POLYMER MATRIX FROM SOLUTION IN SUPERCRITICAL CARBON DIOXIDE Said-Galiyev E; Nikitin L; Vinokur R; Gallyamov M; Kurykin M; Petrova O; Lokshin B; Volkov I; Khokhlov A; Schaumburg K Nesmeyanov Institute of Organo-Element Compounds; Copenhagen,University Chelate complexes of copper diiminate and iron diiminate were synthesised and their physical characteristics were studied. The diffusion of supercritical(SC) carbon dioxide into polyarylate(PAR) Àlms and their impregnation with diiminates were investigated. The equilibrium degree of PAR swelling in SC carbon dioxide was about 10%. The conditions of impregnation were determined. The impregnation was conÀrmed by the FTIR spectroscopic data. Thermal reduction of metal ions was investigated. Transformations of the chelate complexes on the polymerÀlm surface were studied by ESCA. The value of the Auger factor indicated that, after thermal reduction, the copper ion was in a nearly univalent state. The copper content in Àlms was as large as 6.3 wt % and the iron content was 4.5 wt %. The FTIR and ESCA spectroscopic studies showed that, in the course of impregnation, chelate complexes interacted with functional groups of the polymer. Subsequent thermal reduction of metal in air resulted in diiminate evaporation and thermooxidative degradation with ligand decomposition and enrichment of the surface with metal atoms. According to the SAXS data, the size distribution of metal-containing particles ranged from 20 to 60 nm with a maximum at 34 nm. 23 refs. DENMARK; EUROPEAN COMMUNITY; EUROPEAN UNION; RUSSIA; SCANDINAVIA; WESTERN EUROPE

Accession no.800608 Item 220 Industrial and Engineering Chemistry Research 39, No.12, Dec.2000, p.4707-13 COMPARISON OF DYE DIFFUSION IN POLY(ETHYLENE TEREPHTHALATE) FILMS IN THE PRESENCE OF A SUPERCRITICAL OR AQUEOUS SOLVENT Sicardi S; Manna L; Banchero M Torino,Politecnico The diffusion coefficients of a solute (a dyestuff) permeating a PETP Àlm in a supercritical impregnating

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References and Abstracts

system were measured for different working conditions and the results were compared with similar data obtained with the same solute in the same material but in a traditional aqueous system. The experimental technique used was that of the ‘Àlm roll method’ for the experiments conducted in the supercritical system. For the aqueous system, the sorption kinetics of the dyestuff on plane PETP sheets were measured. The results conÀrmed the high gain in the rate of diffusion obtained with the supercritical impregnating system, related to the high plasticising power of supercritical carbon dioxide towards synthetic polymers. Comparison was made with the data obtained by operating with supercritical carbon dioxide at different working pressures and temps. and in the presence of a proper modiÀed (ethanol). 25 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; ITALY; WESTERN EUROPE

Accession no.800602 Item 221 Industrial and Engineering Chemistry Research 39, No.12, Dec.2000, p.4622-6 PRODUCTION OF ENGINEERING PLASTICS FOAMS BY SUPERCRITICAL CARBON DIOXIDE Ming-Tsai Liang; Chang-Ming Wang I-Shou,University Foams of PETP and polycarbonate(PC) were prepared by rapid depressurisation of carbon dioxide-saturated molten resin. It was found that the attainable expansion ratio of the foam produced was generally less than 10. The effect of saturation temp. on the nucleation was mainly a result of the competition between the viscosity effect and the solubility effect. The effect of saturation pressure on the nucleation was, however, two-fold, i.e. the degree of supersaturation and the rate of depressurisation. The effect of lowering the depressurisation rate and changing the depressurisation pattern on the polymeric foams was also investigated. By careful observation of the microstructure, it was concluded that the foaming process was dominated by the nucleation kinetics. This study provided several alternative techniques for controlling the microstructure and the expansion ratio of PETP and PC foams. 12 refs. TAIWAN

Accession no.800596 Item 222 Industrial and Engineering Chemistry Research 39, No.12, Dec.2000, p.4588-96 CONTINUOUS PRECIPITATION POLYMERIZATION OF VINYLIDENE FLUORIDE IN SUPERCRITICAL CARBON DIOXIDE: MODELING THE RATE OF POLYMERIZATION Charpentier P A; DeSimone J M; Roberts G W North Carolina,State University

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The kinetics of the surfactant-free precipitation polymerisation of vinylidene Áuoride(VDF) in supercritical carbon dioxide were studied in a continuous stirred autoclave. Diethyl peroxydicarbonate was used as the free-radical initiator. The stirring rate and agitator design had no effect on the rate of polymerisation(Rp) or on the weight-average molec.wt.(Mw) of the PVDF formed. The fractional conversion of VDF ranged from 7 to 26% and Rp was as high as 0.000027 mol/L.s at 75C and at a VDF feed concentration of 2.5 mol/L. The PVDF was collected as a dry, free-Áowing powder and had Mws up to 150 kg/mol and melt Áow indices as low as 3.0 at 230C. Homogeneous, free-radical kinetics provided a reasonable basis for describing the Rp, despite the heterogeneous nature of the system. The order of the reaction with respect to the monomer was found to be 1.0 and the order with respect to the initiator was 0.5. The experimental data suggested that an inhibitor was present in the monomer or that the monomer itself acted as an inhibitor. 31 refs. USA

Accession no.800595 Item 223 Industrial and Engineering Chemistry Research 39, No.12, Dec.2000, p.4564-6 SYNTHESIS OF SUGAR-CONTAINING AMPHIPHILES FOR LIQUID AND SUPERCRITICAL CARBON DIOXIDE Weijun Ye; DeSimone J M North Carolina,University The use of liquid and/or supercritical carbon dioxide as a processing Áuid is limited by its inability to solubilise highly polar compounds. This problem can be alleviated by the addition of carbon dioxide-philic amphiphiles. The main aim of this study was to design and synthesise materials that had both strong polar moieties and highly carbon dioxidephilic segments. Sugar-containing hydrophobic/hydrophilic Áuorinated copolymers were synthesised by free-radical polymerisation. The degree of solubility of the amphiphiles in carbon dioxide was found to be strongly inÁuenced by the amphiphilic structure, including the polarity of the sugar head (acetal protected and deprotected) and the fraction of carbon dioxide-philic groups. It was also found that the presence of water in the carbon dioxide phase could decrease the solubility of the hydrophilic copolymer. The dispersion polymerisation of 2-hydroxyethyl methacrylate in carbon dioxide was tested by using the hydrophilic amphiphile as a stabiliser. Spherical particles in the submicron size range were obtained. 14 refs. USA

Accession no.800594 Item 224 Industrial and Engineering Chemistry Research 39, No.12, Dec.2000, p.4506-9 IMPREGNATION OF POLYETHYLENE(PE)

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References and Abstracts

WITH STYRENE USING SUPERCRITICAL CARBON DIOXIDE AS THE SWELLING AGENT AND PREPARATION OF PE/POLYSTYRENE COMPOSITES Dan Li; Buxing Han Beijing,Institute of Chemistry The impregnation of LDPE with styrene using supercritical(SC) carbon dioxide as the swelling agent was studied at 35C in the pressure range from 90 to 160 bar. The concentration of styrene in the Áuid phase ranged from 0 to 1.668 mol/l. The soaking time varied from 4 to 36 h. In the presence of AIBN initiator, styrene polymerised to some extent in the soaking process, which resulted in an increase in the mass uptake. LDPE/PS composites were prepared by the further polymerisation of styrene in SC carbon dioxide-swollen LDPE substrates at higher temp. Using this method, the composition of the composites could be controlled by the soaking time, pressure and styrene concentration in the Áuid phase. Some of the PS molecules in LDPE/PS blends entangled with the PE molecules, which caused signiÀcant improvement in the impact strength, the TS and the EB. 23 refs. CHINA

Accession no.800592 Item 225 Industrial and Engineering Chemistry Research 39, No.12, Dec.2000, p.4445-9 POLYMER DEPOSITION FROM SUPERCRITICAL SOLUTIONS FOR SENSING APPLICATIONS Tepper G; Levit N Virginia,Commonwealth University The feasibility and potential advantages of using supercritical Áuid technology for the development of advanced coatings for chemical sensor applications was demonstrated. Polydimethylsiloxane microspheres were deposited onto the sensing surface of a surface acoustic wave device using rapid expansion of supercritical solutions. The sensor output was monitored during repetitive exposure to dilute hexane vapour and was found to exhibit fast reversible behaviour. 16 refs. USA

Accession no.800589 Item 226 Patent Number: EP 1057855 A1 20001206 METHOD OF RECYCLING CROSSLINKED SILICONE COMPOUND WASTE Kawamoto T Yazaki Corp.

water mixture solvent under heating to thereby recover a non-crosslinked silicone or silicone oil-like product from the waste. EUROPEAN COMMUNITY; EUROPEAN UNION; JAPAN; WESTERN EUROPE-GENERAL

Accession no.800456 Item 227 International Journal of Polymeric Materials 47, No.4, 2000, p.657-65 EFFECT OF PRESSURE AND TEMPERATURE ON SUPERCRITICAL CO2 DYEING OF PETDYEING WITH MIXTURES OF DYES Tusek L; Golob V; Knez Z Maribor,University A study was made of the effects of pressure and temperature on the dyeing of PETP in supercritical carbon dioxide. The PETP was dyed with either one dye or with mixtures of two or three dyes and the dyed samples studied by colorimetry and extraction of the dyes from the fabric. It was found that variations in pressure and temperature gave rise to differences in colour, especially when mixed dyes were employed, and that the amount of dye on the fabrics increased with increasing temperature as a result of more rapid molecular motion of the chains and free volume formation in the Àbres. 12 refs. SLOVENIA

Accession no.800194 Item 228 Antec 2000.Conference proceedings. Orlando, Fl., 7th-11th May, 2000, paper 417 CARBON DIOXIDE EXTRUSION FOAMING OF ENGINEERING THERMOPLASTICS Gale M Rapra Technology Ltd. (SPE) The direct injection of supercritical Áuid carbon dioxide was evaluated for the extrusion foaming of a number of engineering thermoplastics (polyether-etherketone, polyphenylsulphone, styrene-maleic anhydride terpolymer, high temperature polycarbonate, polyphenylene oxide and linear polypropylene). A cavity transfer mixer and a static mixer were attached to an extruder to mix and homogenise the liquid carbon dioxide into the molten polymer, and to cool the polymer to the required foaming temperature. A simple measuring system for melt strength measurement was also evaluated. 8 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.799932

This involves hydrolysing crosslinked silicone compound waste by bringing the waste into contact with a solvent having a hydroxyl group in a molecule under a supercritical state or by bringing the waste into contact with an alcohol/

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References and Abstracts

Item 229 Antec 2000.Conference proceedings. Orlando, Fl., 7th-11th May, 2000, paper 414 MICROCELLULAR FOAM MOLDING: ADVANTAGES AND APPLICATION EXAMPLES Jacobsen K; Pierick D Engel North America; Trexel Inc. (SPE) Proprietary injection moulding technology is described for the production of microcellular components. Supercritical carbon dioxide or nitrogen is injected into the extruder, and forms evenly distributing, uniformly-sized cells (5-100 micrometre) in the product. BeneÀts of the process include: weight reduction, cycle time reduction, reduced injection pressures and clamp forces. The production of Àlled nylon mirror brackets and of nylon cable ties are described. CANADA; USA

Accession no.799929 Item 230 Macromolecular Materials and Engineering Vol.283, Nov.2000 p.120-5 A NOVEL, EFFICIENT ROUTE FOR THE CROSSLINKING AND CREEP IMPROVEMENT OF HIGH MODULUS AND HIGH STRENGTH POLYETHYLENE FIBRES Jacobs M; Heijnen N; Bastiaansen C; Lemstra P DSM High Performance Fibers; Eindhoven,University of Technology A new route for the chemical crosslinking of solution-spun, ultra-drawn Ultra-High-Molecular-Weight Polyethylene (UHMW-PE) Àbres is described. Utilising supercritical carbon dioxide as a carrier, UHMW-PE Àbres with a range of draw ratio’s, Young’s moduli and tensile strengths, were impregnated with a radical initiator. Following impregnation, the drawn Àbres were crosslinked with ultra-violet light and Àbres with a high gel content (greater than 90 percent) were obtained. The results indicated that the chemical crosslinking strongly reduces the plateau creep rate of the Àbres and that the threshold stress for irreversible creep is enhanced. Simultaneously, the high Young’s modulus and the high tensile strength of the drawn Àbres are preserved which shows that the long term properties of the Àbres (i.e. creep) are improved without a great deal of loss in terms of short term mechanical properties, for example, Young’s modulus. 41 refs. Accession no.798665 Item 231 Polymer Preprints. Volume 40. Number 2. August 1999. Conference proceedings. New Orleans, La., August 1999, p.671-2 SOLVENT INDUCED CRYSTALLISATION AND SOLID STATE POLYMERISATION OF POLYBISPHENOL A CARBONATE USING SUPERCRITICAL CO2 AS A PROCESSING AID

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Gross S M; Goodner M D; Roberts G W; Kiserow D J; DeSimone J M North Carolina,Chapel Hill University; US,Army; North Carolina,State University (ACS,Div.of Polymer Chemistry) Polycarbonate prepolymer crystallised by supercritical CO2 is rendered in a suitable morphology for solid-state polymerisation, thereby reducing the need for organic solvents in this step of the polymer processing. The solidstate polymerisation of polycarbonate is explored using N2 and supercritical CO2 as the sweep Áuid. Supercritical CO2 as a sweep Áuid offers a few advantages over N2. Supercritical CO2 plasticises polycarbonate, thereby lowering the Tg of the polymer. This allows for lower processing temperatures as solid-state polymerisation needs to be above Tg but below Tm of the polymer. A number of molecules display signiÀcant solubility in liquid or supercritical CO2, including a number of step growth reaction by other products. Although water has a low solubility in supercritical CO2, common condensates, such as acetic acid, neopentyl glycol and phenol have the potential to be using supercritical Áuid extraction methods which would drive the reaction to completion. 10 refs. USA

Accession no.797535 Item 232 Polymer Preprints. Volume 40. Number 2. August 1999. Conference proceedings. New Orleans, La., August 1999, p.551-2 EXPANSION OF POLYSTYRENE USING SUPERCRITICAL CARBON DIOXIDE: EFFECTS OF MOLECULAR WEIGHT AND LOW MOLECULAR WEIGHT COMPONENTS Stafford C M; Russell T P; McCarthy T J Amherst,Massachusetts University (ACS,Div.of Polymer Chemistry) Recently a novel method of creating microcellular foams by use of supercritical (SC) CO2 was reported. Using this method, SC C02 is used to plasticise the polymer matrix and lower the apparent Tg to near ambient temperatures. Upon rapid depressurisation the polymer becomes supersaturated with CO2 gas nucleation of cells occurs and growth of these cells continue until the polymer vitriÀes. Studies on PS foams prepared using this technique have been made. It was found that temperature, initial pressure depth of pressure quench, decompression rate, decompression proÀle and geometric constraints of the foaming vessel can be used to control cell size, cell size distribution and cell shape as well as the compressive properties of the foams. Several other parameters that may affect the foaming process using SC CO2 as the blowing agent are examined. The effects of polymer molecular weight and polydispersity on the Ànal structure of the foam using PS and blends of PS prepared by mixing samples with narrow molecular weight distributions are reported, as is the effect of a low molecular weight component found in commercial PS; it is shown that its

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References and Abstracts

presence dramatically changes resultant foam structure. Varying the concentration of this oligomer allows control of cell size in foams. 8 refs. USA

Accession no.797474 Item 233 Polymer Preprints. Volume 40. Number 2. August 1999. Conference proceedings. New Orleans, La., August 1999, p.829-30 SYNTHESIS OF TWO-STAGE COMPOSITE LATEX PARTICLES BY DISPERSION POLYMERISATION IN CARBON DIOXIDE Young J L; Spontak R J; DeSimone J M North Carolina,Chapel Hill University; North Carolina,State University (ACS,Div.of Polymer Chemistry) The synthesis of two-stage latex particles builds on earlier research on dispersion polymerisations in supercritical CO2. In this Àrst example of a two-stage latex synthesis in CO2, composite particles containing PS and PMMA were prepared and characterised. Two-stage latex particles are prepared by sequential polymerisation of two monomers. There are numerous possible particle morphologies, or distributions of the two polymer phases in the Ànal particles. For example, in a core-shell particle, the secondstage polymer forms a shell around the Àrst polymer core. Other morphologies include inverted, sandwich, raspberry and half-moon. The notation ‘PS/PMMA’ indicates that styrene was polymerised Àrst, followed by MMA. This notation does not necessarily mean that PS will form the core and PMMA will form the shell of the particles. A balance between thermodynamic and kinetic factors determines the morphology of the resulting particles. In considering the particle morphology produced in CO2, a non-polar solvent, it can be predicted that the more polar PMMA should form the core with a PS shell. However, there are other factors to be taken into account. PMMA has been shown by FTIR to have speciÀc interactions with CO2, and PMMA absorbs twice as much CO2 as PS under the same conditions. While PMMA’s polarity should be a driving force to form the core, the interactions with CO2 may be a driving force to form a PMMA shell. However, both PMMA and PS are highly plasticised in CO2, reducing the Tg of both polymers far below the typical polymerisation conditions of 65 deg.C, 345 bar. As a result, the mobility of both polymers may allow for rearrangement of particle morphology during the polymerisation. All of these inÁuences make it difÀcult to predict the morphology of these two-stage latex particles in CO2. 6 refs. USA

Accession no.797284 Item 234 Silicones in Coatings II. Conference proceedings. Florida, USA, 24th-26th March 1998, paper 13

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SUPERCRITICAL FLUIDS AND SILICONES: OVER A DECADE OF APPLICATIONS Wetmore P M; Krukonis V Phasex Corp. (Paint Research Association) Supercritical Áuids (SCFs) achieve improved processing results that are difÀcult, if not impossible, to attain using traditional methods. Motivated by demands for product and process improvements and by increasingly stringent restrictions on liquid organic solvent use, SCFs have been applied for over a decade to address and solve scores of silicone-containing polymer problems. The unique combination of gas-like and liquid-like properties of SCFs is exploited for carrying out operations such as extraction, fractionation, impregnation/deposition and recrystallisation. A broad spectrum of applications with silicone and siloxane polymers is examined and described, including extraction of residual monomers and cyclics from medical tubing and speciality lubricants, fractionation of silicone adhesives and functional siloxane polymers for improved performance, fractionation of copolymers for chemical composition elucidation, and impregnation of polycarbosilane polymers into composites for improving oxidation resistance. 49 refs. USA

Accession no.795777 Item 235 Silicones in Coatings II. Conference proceedings. Florida, USA, 24th-26th March 1998, paper 12 SUPERCRITICAL FLUIDS: ENVIRONMENTALLY ACCEPTABLE REPLACEMENTS FOR ORGANIC SOLVENTS - THE WAY AHEAD Howdle S Nottingham,University (Paint Research Association) Supercritical Áuids are becoming increasingly attractive as environmentally acceptable replacements for organic solvents in chemical reactions and material processing. The properties of supercritical Áuids are highlighted, especially those of supercritical CO2, which offers particular advantages for the handling of silicones; including small molecule reactants, polymers and stabilisers. 33 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.795776 Item 236 Silicones in Coatings II. Conference proceedings. Florida, USA, 24th-26th March 1998, paper 11a WHY SILICONES AND SUPERCRITICAL FLUIDS? Johns K Chemical & Polymer (Paint Research Association)

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Supercritical Áuid technology is an exciting but very much ignored route to new methods of surface modiÀcation. It is, however, a sister to the conventional alternatives to hydrocarbon solvents such as radiation curing, high solids, water-borne, powder coating. The technology can be complementary to these as well as competitive. The interest in SCF here arises from a previous need to develop techniques to replace CFC solvents for the deposition of thin Àlms of Áuorinated liquids. 15 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Details are given of the free radical polymerisation of methyl methacrylate-ethyl methacrylate copolymers in supercritical carbon dioxide. Mention is made of the use of polydimethyl siloxane methacrylate as a stabiliser. Characterisation was undertaken using NMR, SEM, DSC and GPC. The effect of varying AIBN initiator on the composition and molecular weights of the copolymers was also studied. 19 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.793530

Accession no.795775 Item 237 Modern Plastics International 30, No.10, Oct.2000, p.25-7 CARBON DIOXIDE FOAMING IS EXPLORED FOR THIN EXTRUSIONS Leaversuch R D We are told that the use of carbon dioxide as a foaming agent in extruded products made with commodity resins is gradually Ànding its market niche. This article discusses carbon dioxide in foam extrusion in detail, with many examples. RAPRA TECHNOLOGY LTD.; TREXEL; ECLIPSE BLING SYSTEMS; ALUSUISSE COMPOSITES; DUMAPLAST; POLYMER PROCESSING INSTITUTE; TORONTO,UNIVERSITY EUROPEAN COMMUNITY; EUROPEAN UNION; UK; USA; WESTERN EUROPE

Accession no.795336 Item 238 Industrial and Engineering Chemistry Research 39, No.11, Nov.2000, p.4020-3 CONTINUOUS DISTRIBUTION KINETICS FOR THE DEGRADATION OF POLYSTYRENE IN SUPERCRITICAL BENZENE Karmore V; Madras G Indian Institute of Science The degradation kinetics of PS in supercritical benzene was studied at various temperatures. The time evolution of the MWD was obtained by analysing the samples with GPC. Activation energies were determined from the temperature dependence of the rate coefÀcients. 24 refs. INDIA

Accession no.794849 Item 239 Macromolecular Rapid Communications 21, No.15, 23rd Oct.2000, p.1019-23 COPOLYMERISATION OF METHYL AND ETHYL METHACRYLATE IN SUPERCRITICAL CARBON DIOXIDE Giles M R; Hay J N; Howdle S M Nottingham,University; Surrey,University

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Item 240 Journal of Polymer Science: Polymer Physics Edition 38, No.21, 1st Nov.2000, p.2832-40 SOLUBILITY OF VINYLIDENE FLUORIDE POLYMERS IN SUPERCRITICAL CARBON DIOXIDE AND HALOGENATED SOLVENTS Dinoia T P; Conway S E; Jong Sung Lim; McHugh M A Johns Hopkins University; Korea,Institute of Science & Technology; Virginia,Commonwealth University The cloud point behaviours of PVDF and vinylidene Áuoride-22 mol % hexaÁuoropropylene copolymer were studied at temps. up to 250C and pressures up to 3000 bar in supercritical carbon dioxide and halogenated solvents. Cloud point pressures for both polymers decreased as the solvent polarisability, polar moment per molar volume and density increased. It was, however, extremely difÀcult to dissolve either Áuoropolymer in chlorotriÁuoromethane, which had a large polarisability and a small dipole moment. Carbon dioxide was an effective solvent because it complexed with the C-F dipole at low temps. where energetic interactions Àxed the phase behaviour. Polymer structure also had a marked effect on the cloud point pressure. 47 refs. KOREA; USA

Accession no.792538 Item 241 Analytical Chemistry 72, No.17, 1st Sept.2000, p.4230-4 POLYMER NMR CELL FOR THE STUDY OF HIGH-PRESSURE AND SUPERCRITICAL FLUID SOLUTIONS Wallen S L; Schoenbachler L K; Blatchford M A North Carolina,University NMR offers researchers unique, highly localised molecular information. The importance of this technique is well established in studies using chemical shift, spin coupling, and relaxation times providing detailed structural information, determining chemical equilibria and kinetics, and understanding molecular dynamic processes. However, the widespread application of NMR spectroscopy to highpressure liquids and supercritical Áuids has been limited due to the complexity of the necessary instrumentation. One approach to these studies is to build a dedicated

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References and Abstracts

high-pressure probe. Another involves the utilisation of a high-pressure cell designed to Àt in commercially available probes. The design and implementation of a simple, three-piece, high-pressure NMR cell constructed of high-performance polymers is presented. The cell has pressure capabilities of up to 400 bar; however, the ultimate temperature and pressure limits are determined by the speciÀc polymer chosen. High-resolution NMR spectra of methanol modiÀed and tributyl phosphate (TBP) modiÀed supercritical CO2 are presented. An example of supercritical Áuid phase behaviour monitored with NMR is demonstrated for the TBP system in which the chemical shift changes in the 31P nucleus as a function of density are indicative of solution phase separation. The multi-nuclear NMR data demonstrate the utility of this cell for studying supercritical Áuid solution systems relevant to analytical separations and extractions. 41 refs.

(Paint Research Association) Liquid and supercritical CO2 have been studied as environmentally sound alternatives for a variety of solvent-based chemical processes. Of recent signiÀcance is the development of liquid CO2-based commercial dry-cleaning of garments. Complimentary technology emerging in the application of low surface energy coatings, that are derived from Áuoropolymers, to textiles promises several potential advantages over traditional aqueous and solvent based textile treatment processes. Developmental efforts in the area of textile coating from CO2 processes are discussed with emphasis on these advantages and on the support framework within Micelle Technologies’ Micare dry clean system. 15 refs. USA

Accession no.790209

USA

Accession no.792119 Item 242 Advances in Polymer Technology 19, No.4, Winter 2000, p.300-11 EFFECTS OF SUPERCRITICAL CARBON DIOXIDE ON THE VISCOSITY AND MORPHOLOGY OF POLYMER BLENDS Lee M; Tzoganakis C; Park C B Waterloo,University; Toronto,University A PE/PS blend is investigated in the presence of supercritical carbon dioxide using various extrusion conÀgurations. These conÀgurations involving a twin-screw extruder and a single-screw extruder, were specially designed for the study of the rheological and morphological behaviour of this system. The viscosities of the polymer/carbon dioxide and the blend/carbon dioxide solutions were measured at various concentrations of carbon dioxide and PE/PS blending ratios using a wedge die mounted on the twin-screw extruder. The effect of carbon dioxide on the morphology of the PE/PS blends was also investigated using a twin/singlescrew tandem system. This system allowed for preferential dissolution of the carbon dioxide into the matrix and/or dispersed polymer phase. By introducing devolatisation to the tandem system, the morphological behaviours of PE/ PS blends were investigated on unfoamed Àlaments. It is generally concluded that the mixing of the two polymers was improved by the dissolution of carbon dioxide. 24 refs. CANADA

Accession no.791802 Item 243 Fluorine in Coatings III. Conference proceedings. Orlando, Fl., 25th-27th January 1999, paper 36 FLUOROPOLYMER COATINGS FROM LIQUID AND SUPERCRITICAL CARBON DIOXIDE DeYoung J; Romack T MICELL Technologies

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Item 244 Fluorine in Coatings III. Conference proceedings. Orlando, Fl., 25th-27th January 1999, paper 33 FLUOROCOPOLYMER COATINGS FROM ENVIRONMENTALLY BENIGN SUPERCRITICAL FLUIDS McHugh M A; Coneay S E; Dinioa T P John Hopkins University (Paint Research Association) The solubility of various Áuorocopolymers is determined in environmentally benign supercritical Áuid (SCF) solvents with an emphasis on CO2 and hydroÁuorocarbons. The objective is to investigate the inÁuence of Áuorocopolymer architecture on phase behaviour and to relate the differences to properties of coatings obtained from Áuoropolymer SCF solutions. The principles of molecular thermodynamics are used to interpret phase behaviour. Examples of coatings are presented. 9 refs. USA

Accession no.790206 Item 245 Polymer Process Engineering 99. Conference proceedings. London, June 1999, p.28-36 SUPERCRITICAL ENHANCED PROCESSING Kazarian S G; Briscoe B J; Lawrence C J London,Imperial College of Science,Technology & Medicine Edited by: Coates P D (Institute of Materials; UK,Interdisciplinary Research Centre in Polymer Science & Technology; Bradford,University) Supercritical Áuids have a unique and valuable potential for enhanced processing of polymeric based materials and soft solids. This is especially important due to the need to develop environmentally friendly chemical synthesis and materials processing systems. As a consequence there is

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a very real need to understand how supercritical Áuids interact with polymeric materials, in particular how this medium may modify many facets of process operation. This understanding will help engineers to utilise molecular level information for improving macroscopic properties of polymeric materials by supercritical Áuid processing. Spectroscopy is an economic tool to probe interactions at a molecular level. The beneÀcial changes, in the context of processing, in polymeric systems induced by supercritical carbon dioxide are currently being elucidated via in situ spectroscopic methods that provide a route to optimise new supercritical enhanced polymer processing operations. Spectroscopic data provide a fundamental understanding of the origin of the plasticising effect of CO2 on glassy polymers. This effect results, for example, in a viscosity reduction which facilitates processing of polymers due to lower shear stresses. Also, since supercritical CO2 can plasticise glassy polymers, it can also modify semicrystalline polymers by plasticising their amorphous phase resulting in induced crystallisation. The use of supercritical CO2 as a plasticiser therefore shows great promise in assisting the production of many polymeric based materials. In particular, an important application of CO2-induced polymer plasticisation will be in the processing of injection moulded or extruded polymer materials. 43 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.790078 Item 246 Macromolecular Chemistry and Physics 201, No.13, 11th Sept.2000, p.1532-9 KINETICS OF THE EARLY STAGE OF DISPERSION POLYMERIZATION IN SUPERCRITICAL CARBON DIOXIDE AS MONITORED BY TURBIDIMETRIC MEASUREMENTS. I. METHOD Fehrenbacher U; Muth O; Hirth T; Ballauff M Karlsruhe,University; Fraunhofer-Institut fuer Chemische Technologie The dispersion polymerisation of methyl methacrylate in supercritical carbon dioxide in the presence of polydimethylsiloxane-monomethyl acrylate was monitored in situ by turbidimetry at 330 bar and 60C. The turbidity spectra were recorded directly in the autoclave to produce the average number of particles per unit volume and the average particle diameter developing with time. The experimental set-up allowed the early stages of nucleation and particle formation to be monitored. The morphology of a quenched sample after 500 s reaction time was shown by SEM imaging. 34 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.789341

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Item 247 Journal of Macromolecular Science B B39, No.4, 2000, p.561-7 DIFFUSION OF ORGANOMETALLIC COMPOUNDS INTO HIGH-SPEED SPUN POLY(ETHYLENE TEREPHTHALATE) FIBRE IN SUPERCRITICAL CARBON DIOXIDE FLUID Kawahara Y; Kikutani T Kyoto,Institute of Technology The dyeability of high-speed spun PETP Àbres, which had higher crystallinity, larger crystallite sizes and lower birefringence than conventional PETP Àbres, in supercritical carbon dioxide Áuid was investigated using Fe3(CO)12, as a dye. The high-speed spun Àbres exhibited a larger dye uptake, at temperatures between 50 and 80C and a pressure of 18.2 to 19.3 MPa. The penetration of the dye into the Àbres was inÁuenced by the size of the channels caused by Àbrillation of the Àbres in the supercritical carbon dioxide Áuid. 10 refs. JAPAN

Accession no.786360 Item 248 Journal of Applied Polymer Science 77, No.14, 29th Sept.2000, p.3228-33 DEPOLYMERIZATION OF POLY(BUTYLENE TEREPHTHALATE) USING HIGHTEMPERATURE AND HIGH-PRESSURE METHANOL Shibata M; Masuda T; Yosomiya R; Meng Ling-Hui Chiba,Institute of Technology; Harbin,Institute of Technology PBTP was depolymerised in excess methanol under high temperature (473-523 K) and high pressure (4-14 MPa) conditions. Depolymerisation was carried out at 483 K and 4-12 MPa, and at 513 K and 6-14 MPa. The temperature had a great effect on the depolymerisation rate, but the reaction pressure did not. Under the former conditions, depolymerisation took over 80 min, but only about 20 min under the latter conditions. The se results showed that the supercritical state of methanol was not a key factor in the depolymerisation reaction. A kinetic study of the reaction at 473-523 K and 12 MPa showed that the decomposition rate constant of PBTP increased dramatically when the reaction temperature was higher than the melting point of PBTP (500 K). This indicated that partial miscibility of the molten PBTP and methanol was an important factor for the short-time depolymerisation. 9 refs. CHINA; JAPAN

Accession no.784903 Item 249 Polymer International 49, No.7, July 2000, p.712-8 PREPARATION AND MORPHOLOGY CHARACTERISATION OF MICROCELLULAR

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References and Abstracts

STYRENE-CO-ACRYLONITRILE (SAN) FOAM PROCESSED IN SUPERCRITICAL CO2 Lee K N; Lee H J; Kim J H Yonsei,University

morphology development was observed. Viscosity reduction of PS and PMMA were measured using a slit die rheometer attached to a twin-screw extruder. 24 refs.

Microcellular polymeric foam structures are generated using a pressure-induced phase separation in concentrated mixtures of supercritical CO2 and SAN. The process typically generates a microcellular core structure encased by a non-porous skin. Pore growth occurs through two mechanisms: diffusion of CO2 from polymer-rich into the pores and also through CO2 gas expansion. The effects of saturation pressure, temperature and swelling time on the cell size, cell density and bulk density of the porous materials are studied. Higher CO2 pressures (hence, higher Áuid density) provide more CO2 molecules for foaming generated lower interfacial tension and viscosity in the polymer matrix, and thus produce low cell size but higher cell densities. This trend is similar to what is observed in swelling time series. While the average cell size increases with increasing temperature, the cell density decreases. The trend of bulk density is similar to that of cell size. 15 refs.

Accession no.782988

KOREA

Accession no.784067 Item 250 Polymer Engineering and Science 40, No.8, Aug.2000, p.1942-52 RECYCLING OF POLYETHYLENE TEREPHTHALATE INTO CLOSED-CELL FOAMS Japon S; Leterrier Y; Manson J-A E Lausanne,Ecole Polytechnique Federale The increase of the elongational viscosity of recycled PETP was investigated with the aim of producing closed-cell foams by means of a cost-effective reactive extrusion technique. A recycled PETP grade containing contamination levels of PVC and PE was compared with virgin bottle-grade PETP as a reference. Data are presented for the microstructure of the foams obtained in a high-pressure vessel using supercritical carbon dioxide. 38 refs. SWITZERLAND; WESTERN EUROPE

Accession no.782997 Item 251 Polymer Engineering and Science 40, No.8, Aug.2000, p.1850-61 EFFECT OF SUPERCRITICAL CARBON DIOXIDE ON MORPHOLOGY DEVELOPMENT DURING POLYMER BLENDING Elkovitch M D; Lee L J; Tomasko D L Ohio,State University

USA

Item 252 ACS Polymeric Materials: Science & Engineering. Spring Meeting 2000.Volume 82.Conference proceedings. San Francisco, Ca., 26th-30th March 2000, p.41-2 DRAWING OF NYLON 6,6 IN HIGH PRESSURE CARBON DIOXIDE Hobbs T; Lesser A J Massachusetts,University (ACS,Div.of Polymeric Materials Science & Engng.) Fibre bundles of polyamide-6,6 were drawn to a draw ratio of 3.8 at room temperature and subsequently drawn in supercritical carbon dioxide at a pressure of 238 atm at temperatures of 95, 110, 130, and 145 C. Carbon dioxide was used as both a plasticiser and a pressure transmitting medium, high temperatures being used to promote crystallisation. The maximum draw ratio achieved was 6.1 at 130 C. The Àbres had 25% higher crystallinity and 30% higher strength values compared with conventional air-drawn Àbres. 11 refs. USA

Accession no.782850 Item 253 Plastics in Building Construction 24, No.8, 2000, p.5 MICROCELLULAR FOAM TECHNOLOGY USED FOR TWO PRODUCTS Brief details are given of the applications of two companies who are using the Mucell extrusion technology from Trexel Inc. to manufacture building/construction products. Alusuisse Composites Inc. is using the technology to manufacture microcellular foam products for its line of FOAM-X material laminated foam-centered boards used for graphic arts and three-dimensional moulding. Eclipse Blind Systems Inc. has begun distributing a range of high-performance vertical blind slates manufactured from PVC with this new process which uses supercritical Áuids of atmospheric gases to create microscopic cells throughout thermoplastic polymers to achieve improved parts performance and a reduction of production costs. TREXEL INC.; ALUSUISSE COMPOSITES INC.; ECLIPSE BLIND SYSTEMS INC. USA

Accession no.782788

Supercritical carbon dioxide was added during compounding of PS and PMMA and the resulting

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Item 254 ACS, Polymeric Materials Science & Engineering Fall Meeting 1999. Volume 81. Conference proceedings. New Orleans, La., 22nd-26th Aug.1999, p.47-8 SPIN COATING AND PHOTOLITHOGRAPHY USING LIQUID AND SUPERCRITICAL CARBON DIOXIDE Hoggan E N; Kendal J L; Flowers D; Carbonell R G; DeSimone J M North Carolina,State University (ACS,Div.of Polymeric Materials Science & Engng.) The conventional manufacturing of integrated circuits utilises two solvent intensive steps, spin coating of a photoresist layer and the development of the image after exposure. The complexity of modern semiconductor devices necessitates large numbers of material layers, thus requiring these solvent intensive steps to be repeated 30 times or more in the processing of a single wafer. This creates vast amounts of solvent waste. For example, a typical semiconductor sing line which produces 5,000 wafers per day will generate 2,000 gallons of waste developing solution and an equivalent amount of contaminated water. This does not include the large amount of organic waste generated by spin coating processes. The health and environmental hazards posed by these solvents has led to increased research on alternative processing solvents. One promising alternative is carbon dioxide. CO2 is non-toxic non-Áammable, inexpensive, environmentally benign and recyclable. Despite its promise, CO2 has not become widely used due to several challenges. Work conducted to resolve these issues is described. The synthesis of suitable resists, the construction of a highpressure spin coating apparatus, and the results obtained with these materials are reported. 8 refs. USA

Accession no.780710

Item 256 Macromolecular Symposia Vol.153, March 2000, p.77-86 CATIONIC AND ANIONIC RING-OPENING POLYMERISATION IN SUPERCRITICAL CO2 Mingotaud A-F; Dargelas F; Cansell F CNRS Details are given of the anionic and pseudoanionic polymerisation of caprolactone in supercritical carbon dioxide. Results are also presented for the cationic polymerisation of octamethylcyclotetrasiloxane and phenyloxazoline. 17 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; WESTERN EUROPE

Accession no.778920 Item 257 Macromolecules 33, No.10, 16th May 2000, p.3505-7 POLYMERIZATION OF VINYLPYRROLIDONE IN SUPERCRITICAL CARBON DIOXIDE WITH DIBLOCK COPOLYMER STABILIZER Berger T; McGhee B; Scherf U; Steffen W Max-Planck-Institut fuer Polymerforschung Polystyrene-block-polydimethylsiloxane diblock copolymers were evaluated as stabilisers for the radical polymerisation of vinylpyrrolidone in supercritical carbon dioxide. The presence of the stabiliser resulted in the formation of uniform, spherical microparticles of polymer, with a wide molecular weight distribution, attributed to surface plasticisation of the growing particles creating inhomogeneous polymerisation conditions. The polymerisation was very sensitive to the reaction parameters, particularly the stabiliser concentration. 12 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Item 255 Macromolecules 33, No.11, 30th May 2000, p.4008-14 IN-SITU INVESTIGATION ON THE MECHANISM OF DISPERSION POLYMERISATION IN SUPERCRITICAL CARBON DIOXIDE Li G; Yates M Z; Johnston K P; Howdle S M Texas,University; Nottingham,University The effect of stabilisers on the particle formation stage in dispersion polymerisation of methyl methacrylate in supercritical carbon dioxide was studied by in-situ turbidimetry. The point at which the particle number density becomes equivalent to the Ànal particle number density was determined. 45 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; USA; WESTERN EUROPE

Accession no.779858

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Accession no.778276 Item 258 Biomaterials 21, No.15, 2000, p.1587-93 CHARACTERISATION OF COPOLYMERS OF LACTIC AND GLYCOLIC ACID FOR SUPERCRITICAL FLUID PROCESSING Engwicht A; Girreser U; Muller B W Kiel,Christian-Albrecht-University Polymers of lactic and glycolic acid are often used for the production of injectable microparticles with controlled drug release. In the variety of processes used for the microparticle formulation, the aerosol solvent extraction system (ASES) is rather special. Microparticle formation and drying take place in one step by precipitating a methylene chloride solution of the polymer in supercritical CO2. This process sets special requirements to the polymers in crystallinity, solubility and thermal behaviour

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References and Abstracts

that are best fulÀlled by blocked copolymers. A number of lactide-co-glycolide polymers blocked distribution of the co-monomers by NMR spectroscopy and powder diffraction. The molar ratios are determined by 1H NMR spectroscopy to verify the manufacturer’s declarations of the purchased specimens. Additionally, the block length is determined by application of 13C NMR. Therefore, a method is modiÀed and evaluated in order to calculate the length of lactide and glycolide sequences in the polymer. The impact of synthesis conditions on block length and crystallinity, and the impact of the blocking on both crystallinity and solubility of the polymers, are examined. 11 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.778044 Item 259 Patent Number: EP 1006143 A1 20000607 APPARATUS FOR DECOMPOSITION AND RECOVERY OF POLYURETHANE RESIN Kodama K; Murayama K; Kumaki T; Kasuya F; Nagase Y; Nakata M; Nishida S Takeda Chemical Industries Ltd.; Kobe Seiko Sho KK This includes a Áuidiser, which Áuidises the polyurethane resin as a target compound of hydrolysis decomposition, a reactor, which hydrolyses the Áuidised target compound with either a supercritical water or high-temperature high-pressure water to a decomposition product mixture, a water supplier, which feeds either supercritical water or high-temperature high-pressure water to the reactor and a post-processor, which causes the decomposition product mixture discharged from the reactor to be subjected to a post treatment procedure, such as dehydration, addition, distillation, separation, or liquid separation, to recover a polyamine compound and/or a polyol compound. The required energy cost is reduced as is the size of the machine. Foreign substances are removed from the shredder dust and the required quantities of substances for decomposition are reduced. EUROPEAN COMMUNITY; EUROPEAN UNION; JAPAN; WESTERN EUROPE-GENERAL

Accession no.777712 Item 260 British Plastics and Rubber May 2000, p.4-9 FOAM EXTRUSION OF ENGINEERING AND COMMODITY POLYMERS USING CARBON DIOXIDE AS A BLOWING AGENT Gale M Rapra Technology Ltd. The use of carbon dioxide as blowing agent has been shown to be feasible on a laboratory scale using a conventional extruder retroÀtted with a Cavity Transfer Mixer to mix gas and polymer with some cooling, followed

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by further cooling in a static mixer heat exchanger. Using this arrangement, foams can be extruded from a number of engineering polymers including polyaryletherketone. In addition to the ability to foam engineering polymers, carbon dioxide as blowing agent should give considerable economic savings for commodity plastics foaming in comparison to chemical blowing agents. 5 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.777093 Item 261 Polymer Degradation and Stability 65, No.3, 1999, p.373-86 CHARACTERISTICS OF POLYETHYLENE CRACKING IN SUPERCRITICAL WATER COMPARED TO THERMAL CRACKING Moriya T; Enomoto H Tohoku Electric Power Co.Inc.; Tohoku,University PE cracking obtained from hydrothermal experiments with supercritical water was compared to water-free thermal cracking. The degradation mechanism of HDPE and the contribution of supercritical water to degradation were also considered by analysing the products in the aqueous phase after the reaction. 21 refs. JAPAN

Accession no.776428 Item 262 Polymer Process Engineering ‘97. Conference proceedings. London, July 1997, p.197-201 CHEMICAL ASSIST FOAMING AND THE ROLE OF SUPERCRITICAL FLUIDS IN EXTRUSION Reedy M E Reedy International Corp. (Institute of Materials) Processing and properties of polymers are the two most important criteria that are many times in conÁict with each other. The processor looks for the largest processing window while the designer looks for good surfaces, optimum density reduction, excellent thermal properties and great impact behaviour. Now, chemical foam assist (CFA) technology enables both commodity and engineering polymers to process more easily and with improved properties for a wide variety of extrusion processes. Carbon dioxide is used extensively as a physical blowing agent in the production of thermoplastic foams. For example, in the extrusion of foam sheet, carbon dioxide alone or in conjunction with other gases can produce lightweight products with excellent physical properties. Recent studies have shown that CO2 has unique low pressure solubility. In most polymers, CO2 when pressurised to 1,700 psi becomes a supercritical Áuid and acts as a solvent resulting in a lowering of the glass transition temperature and improved polymer melt Áow

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References and Abstracts

USA

terephthalate and ethylene glycol) was investigated and the proper conditions for the depolymerisation of PETP with supercritical methanol established. The maximum yield of dimethyl terephthalate was 94% and that of ethylene glycol was 80%. Supercritical methanol minimised secondary decomposition or side reactions of the monomers. 8 refs.

Accession no.775992

JAPAN

characteristics. During transition between a supercritical Áuid and a gas, the CO2 will absorb heat energy, improve melt cooling and consequently facilitate increased extrusion rates. The improved melt Áow characteristics and heat energy absorption result in improved physical properties of extruded board and sheet materials. 8 refs.

Accession no.772137 Item 263 Materials World 8, No.5, May 2000, p.10-2 CO2 UNDER PRESSURE - A CLEAN SOLUTION FOR POLYMER PROCESSING Cooper A; Howdle S Liverpool,University; Nottingham,University The use of supercritical carbon dioxide during the synthesis of polymers is examined, and its ability to produce novel materials which are difÀcult to obtain by more conventional methods. Supercritical carbon dioxide, as a solvent for polymer synthesis, also addresses concerns over volatile organic solvent emissions and the generation of aqueous waste streams. It can be used to produce a variety of polymers with tailored properties such as polymeric implants with modiÀed bioproperties, and the building macroporous monoliths.

Item 266 Macromolecules 33, No.6, 21st March 2000, p.1917-20 DISPERSION POLYMERIZATION OF 1-VINYL-2PYRROLIDONE IN SUPERCRITICAL CARBON DIOXIDE Carson T; Lizotte J; Desimone J M North Carolina,State University

EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

The low molec.wt. polymeric surfactant poly(1,1dihydroperÁuorooctyl acrylate)(polyFOA) was used in the dispersion polymerisation of 1-vinyl-2-pyrrolidone in supercritical carbon dioxide. It was found that increasing concentrations of polyFOA yielded a decrease in polymer particle diameter, while increasing the monomer concentration produced an increase in particle size. No signiÀcant change was observed in the particle morphology for polymerisations conducted at different pressures. 20 refs.

Accession no.773641

USA

Accession no.771863 Item 264 Patent Number: US 6025459 A1 20000215 SYNTHESIS OF POLYAMIDES IN LIQUID AND SUPERCRITICAL CO2 DeSimone J; Givens R; Ni Y North Carolina,University A nylon salt is condensed in carbon dioxide to form a polyamide and water. A polyamide is formed by polymerising a lactam monomer in carbon dioxide to form a polyamide. USA

Accession no.773536 Item 265 Polymer Journal (Japan) 32, No.2, 2000, p.178-81 RECOVERY OF CONSTITUENT MONOMERS FROM POLYETHYLENE TEREPHTHALATE WITH SUPERCRITICAL METHANOL Sako T; Okajima I; Sugeta T; Otake K; Yoda S; Takebayashi Y; Kamizawa C Japan,National Institute of Materials & Chemical Research The inÁuence of temperature, pressure and reaction time on the recovery of the constituent monomers (dimethyl

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Item 267 Macromolecules 33, No.5, 7th March 2000, p.1565-9 DISPERSION POLYMERISATION OF ACRYLONITRILE IN SUPERCRITICAL CARBON DIOXIDE Shiho H; DeSimone J M JSR Corp.; North Carolina,University Details are given of the dispersion polymerisation of acrylonitrile in carbon dioxide using a styrenedihydroperfluorooctyl acrylate block copolymer as a stabiliser. The effects of the initial concentrations of acrylonitrile and the stabiliser and the reaction pressure on the resulting size of the colloidal particles are discussed. 31 refs. JAPAN; USA

Accession no.771261 Item 268 Journal of Vinyl and Additive Technology 6, No.1, March 2000, p.39-48 CHALLENGE TO FORTYFOLD EXPANSION OF BIODEGRADABLE POLYESTER FOAMS BY USING CARBON DIOXIDE AS A BLOWING

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References and Abstracts

AGENT Park C B; Liu Y; Naguib H E Toronto,University A report is presented on the development of an approach for making extruded, low-density, biodegradable polybutylene succinate foams using supercritical carbon dioxide, as the blowing agent. The aim of the approach was the promotion of large volume expansion and production of a Àne cell structure by the prevention of cell coalescence, complete dissolution of blowing agent in the melt, reduction of gas diffusivity and optimisation of processing conditions in the die. The effects of processing conditions on the volume expansion ratio and cell population density and of the amount of blowing agent on the volume expansion ratio and die pressure are discussed. 35 refs. CANADA

Accession no.769389 Item 269 Surface Coatings International 83, No.3, March 2000, p.106-10 SUPERCRITICAL FLUIDS - A POTENTIAL REVOLUTION IN WOOD TREATMENT AND COATING Hay J N; Johns K Surrey,University; Chemical & Polymer The need to Ànd environmentally friendly alternatives for wood coatings is discussed, with particular reference to the use of supercritical Áuids. European softwoods could have their durability increased by increasing their hydrophobicity and minimising their biodegradation. The waste disposal and recycling of treated woods can be increased by the efÀcient use of more appropriate biocides, coupled with the ability to remove these prior to disposal or recycling. The use of supercritical carbon dioxide as a carrier for coating and impregnation systems is examined. 35 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.768106 Item 270 Journal of Materials Chemistry 10, No.2, Feb.2000, p.207-34 POLYMER SYNTHESIS AND PROCESSING USING SUPERCRITICAL CARBON DIOXIDE Cooper A I Liverpool,University A review is presented on recent developments in polymer synthesis and processing using liquid and supercritical carbon dioxide. Polymer synthesis techniques discussed include homogeneous polymerisation, precipitation polymerisation, dispersion polymerisation, emulsion and seeded polymerisation, synthesis of porous polymers, bulk condensation polymerisation using carbon dioxide as a plasticiser, and formation of polymer blends. Polymer processing aspects covered include fractionation,

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extraction and puriÀcation, impregnation and dyeing, heterogeneous chemical modiÀcation, manufacture of microcellular materials, particle formation, and coatings and lithography. 271 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.766867 Item 271 Industrial and Engineering Chemistry Research 39, No.2, Feb.2000, p.245-9 CHEMICAL RECYCLING OF PHENOL RESIN BY SUPERCRITICAL METHANOL Ozaki J; Djaja S K I; Oya A Gunma,University The reaction of phenolic resin in supercritical methanol was studied with variations in temp. from 300 to 420C and in reaction times from 30 to 150 min. The conversion increased rapidly above 350C to give 94% at maximum at 420C and the gas fraction also increased at the same time. When a longer reaction time was used from the reaction at 400C, the conversion increased without giving additional gas product. From the point of view of liquefaction, the longer reaction at lower temp. would give better results. A gas chromatographic study revealed that the liquid product included phenol and its methylated derivatives. The carbon content of the solid product was higher than the initial phenol resin, showing that some carbonisation took place during the reaction. 21 refs. JAPAN

Accession no.766857 Item 272 Polymer News 25, No.2, Feb.2000, p.68-9 SUPERCRITICAL FLUID TECHNOLOGY IN POLYMERISATION REACTIONS Rudzinski W E; Aminabhavi T M Southwest Texas,State University An overview is presented of the current understanding of supercritical Áuid technology relating to Áuoropolymers. Various polymerisations and copolymerisations carried out in supercritical Áuids are discussed. 3 refs. USA

Accession no.766708 Item 273 Macromolecules 33, No.1, 11th Jan.2000, p.40-5 CRYSTALLISATION AND SOLID-STATE POLYMERISATION OF POLYBISPHENOL A CARBONATE FACILITATED BY SUPERCRITICAL CARBON DIOXIDE Gross S M; Roberts G W; Kiserow D J; DeSimone J M North Carolina,University

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Details are given of the solid-state polymerisation of bisphenol A carbonate using supercritical carbon dioxide to induce crystallinity in low molecular weight polycarbonate beads. Crystallisation was studied as a function of time, temperature, molecular weight and pressure. The molecular weight and percent crystallinity of the polymer were determined as a function of time and radial position in the bead. 25 refs. USA

Accession no.764719 Item 274 Polymer Engineering and Science 39, No.10, Oct.1999, p.2075-84 SUPERCRITICAL CARBON DIOXIDE ASSISTED BLENDING OF POLYSTYRENE AND POLY(METHYL METHACRYLATE) Elkovitch M D; Tomasko D.L; Lee L J Ohio State,University Supercritical carbon dioxide addition has been used to assist in the blending of polymethylmethacrylate and polystyrene. Whether the melt viscosities of the two polymers are equal, or varying with a viscosity ratio of about 20, the results show a reduction in size of the minor or dispersed phase. Addition of the carbon dioxide lowers the melt viscosities, by being absorbed between the polymer chains causing an increase in free volume, resulting in a decrease in chain entanglement and thus increased chain mobility. Single and twin screw extruders were used in the studies. 29 refs. USA

Accession no.760460 Item 275 Patent Number: EP 972626 A2 20000119 METHOD OF ADDING SUPERCRITICAL CARBON DIOXIDE TO THERMOPLASTIC RESIN AND FOAMED ARTICLES Nishikawa S; Sugihara E; Takedachi M; Yorita K; Inoue H; Shimada Y; Eriguchi M Mitsui Chemicals Inc. Carbon dioxide is charged from a liqueÀed carbon dioxide cylinder into a predetermined amount deliverable pump while allowing the carbon dioxide to remain in a liqueÀed state. When the carbon dioxide is pressurised and delivered by the pump, the delivery pressure of the carbon dioxide is controlled at an optional pressure within a range from a critical pressure (7.4 MPa) of carbon dioxide to 40 MPa to deliver carbon dioxide without any Áuctuation of the amount of the delivery by setting up the pressure of a pressure control valve. The carbon dioxide is heated to a critical temperature (31C) of carbon dioxide or higher to convert it into supercritical carbon dioxide, which is then added to the thermoplastic resin in the forming machine. JAPAN

Accession no.760435

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Item 276 Macromolecules 32, No.22, 2nd Nov.1999, p.7610-6 EXPANSION OF POLYSTYRENE USING SUPERCRITICAL CARBON DIOXIDE: EFFECTS OF MOLECULAR WEIGHT, POLYDISPERSITY, AND LOW MOLECULAR WEIGHT COMPONENTS Stafford C M; Russell T P; McCarthy T J Massachusetts,University Closed cell foams of broad MWD commercial PS samples, prepared by expansion of supercritical carbon dioxide-swollen specimens, exhibited cell diameters that were 3 to 10 times larger than those of foams prepared from PS samples with narrow MWDs. Cell diameters for narrow MWD samples were independent of molec. wt. from 147 to 1050K. Simulated polydisperse samples prepared by blending narrow MWD samples ranging from 560 to 1050K and a polydisperse sample prepared by radical polymerisation produced foams with cells of the same size as in foams prepared from the narrow MWD samples. These observations suggested that molec.wt. and polydispersity were not important factors in determining cell size and were not responsible for the disparity in cell sizes described. This disparity was due to the presence of a very low molec.wt. component in the commercial samples. Extraction of this component reduced the cell diameter of resulting foams to that of the narrow MWD samples. Addition of a styrene oligomer to a narrow MWD sample resulted in foams with larger cell diameters. Varying the concentration of this oligomer allowed control of cell size in foams. Classical nucleation theory could not explain these observations, suggesting that an alternative mechanism of cell formation was active. 21 refs. USA

Accession no.759217 Item 277 Polymer Journal (Japan) 31, No.9, 1999, p.714-6 DECOMPOSITION OF POLYETHYLENE 2,6-NAPHTHALENE DICARBOXYLATE TO CONSTITUENT MONOMERS USING SUPERCRITICAL METHANOL Sako T; Sugeta T; Otake K; Yoda S; Takebayashi Y; Okajima I Tsukuba,National Institute of Materials & Chemical Research The depolymerisation of polyethylene 2,6-naphthalene dicarboxylate (PEN) to its constituent monomers and oligomer using supercritical methanol without a catalyst was investigated as a means of chemical recycling of waste PEN. Attention focused on the analysis of the decomposition products, which included both solids and liquids. The amount of gases produced was negligible, as the decomposition temperature was only 623 K. The solid phase consisted of unreacted PEN, undissolved

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References and Abstracts

monomer dimethyl 2,6-naphthalene dicarboxylate (DMN) and oligomer. The oligomer was deÀned as a product which was hydrolysed with sodium hydroxide aqueous solution to disodium 2,6-naphthalene dicarboxylate and ethylene glycol. The liquid phase contained ethylene glycol monomer, DMN monomer and oligomer. 5 refs. JAPAN

Accession no.758005 Item 278 Industrial and Engineering Chemistry Research 38, No.10, Oct.1999, p.3655-62 POLYMER COATINGS BY RAPID EXPANSION OF SUSPENSIONS IN SUPERCRITICAL CARBON DIOXIDE Jae-Jin Shim; Yates M Z; Johnston K P Texas,University Suspensions of poly(2-ethylhexyl acrylate) in supercritical carbon dioxide formed by dispersion polymerisation with a polydimethylsiloxane-based surfactant were sprayed to form uniform Àlms. The viscosity reduction of the dispersed phase caused by dissolved carbon dioxide was crucial for atomisation to produce Àne droplets and for coalescence and levelling on the surface to form a uniform Àlm. Resuspension of the polymer after depressurisation and repressurisation led to fairly large droplets in the suspension which produced a Àlm nearly as uniform as the original one. Inferior films were produced by suspensions without surfactant. Unlike previous studies of rapid expansion of homogeneous polymer solutions and related techniques, Àlms were produced from concentrated polymer mixtures without any organic solvent. 24 refs. USA

Accession no.756190 Item 279 Industrial and Engineering Chemistry Research 38, No.10, Oct.1999, p.3622-7 SUPERCRITICAL FLUID SEPARATION FOR SELECTIVE QUATERNARY AMMONIUM SALT PROMOTED ESTERIFICATION OF TEREPHTHALIC ACID Brown J S; Lesutis H P; Lamb D R; Bush D; Chandler K; West B L; Liotta C L; Eckert C A; Schiraldi D; Hurley J S Georgia,Institute of Technology; KoSa; Buckeye Technologies A study was conducted of the selective removal of a desired reaction intermediate with a supercritical Áuid in a new synthesis route to PETP, avoiding ethylene glycol. The esteriÀcation of terephthalic acid with ethylene oxide in a supercritical Áuid was successfully catalysed using a series of quaternary ammonium salts to form mono(2hydroxyethyl terephthalate). This desired monoester was removed from the non-volatile bed of terephthalic acid and catalyst by continuous extraction with supercritical

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Áuid before subsequent reaction to the diester could take place. 11 refs. USA

Accession no.756188 Item 280 Cellular Polymers 18, No.5, 1999, p.301-13 MEASUREMENT AND PREDICTION OF BLOWING AGENT SOLUBILITY IN POLYSTYRENE AT SUPERCRITICAL CONDITIONS Seong Uk Hong; Albouy A; Duda J L Pennsylvania,State University Partition coefÀcients of several blowing agents (HFCs AND HCFCs) in PS at the infinitely dilute solvent concentration region were measured using capillary column inverse gas chromatography. The measured partition coefÀcients were then used to calculate binary interaction parameters in the perturbed soft chain theory(PSCT). Using these values, solubility data of blowing agents in the Ànite solvent concentration region were predicted as a function of pressure in accordance with the PSCT. The prediction results from the PSCT were comparable with the experimental data in the literature. In addition, the PSCT was found to be very sensitive to the partition coefÀcient and, hence, the binary interaction parameter. 21 refs. USA

Accession no.755884 Item 281 Macromolecules 32, No.9, 4th May 1999, p.3167-9 SOLID STATE POLYMERISATION OF POLYCARBONATES USING SUPERCRITICAL CARBON DIOXIDE Gross S M; Flowers D; Roberts G; Kiserow D J; DeSimone J M North Carolina,University; US,Army Research OfÀce Polycarbonate prepolymer was synthesised by step-growth polymerisation of bisphenol A and diphenyl carbonate using an aqueous solution of lithium hydroxide as the initiator. The prepolymer formed beads when dripped into room-temperature water.The beads were crystallised by treatment with supercritical carbon dioxide. The crystallisation of the low molecular weight (2500) polycarbonate was studied as a function of time and temperature. DSC gave melting point, Tg, enthalpy of fusion and crystallinity. The crystallised prepolymer was then polymerised in the solid state at 3C below the onset of melting (160C) and samples removed after 2, 4, 6, and 12 hours. Because the melting point increased with polymerisation the process was repeated at 180C, 205C, 230C and 240C. It was repeated also with a 5000 molecular weight prepolymer. The development of crystallinity,

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molecular weight and melting point over 12h is shown. 12 refs. USA

Accession no.754788 Item 282 Journal of Polymer Science: Polymer Physics Edition 37, No.19, 1st Oct.1999, p.2771-81 RHEOLOGY OF MOLTEN POLYSTYRENE WITH DISSOLVED SUPERCRITICAL AND NEAR-CRITICAL GASES Kwag C; Manke C W; Gulari E Wayne State,University The viscosities of PS melts containing three different dissolved gases, carbon dioxide and the refrigerants R134a (1,1,1,2-tetrafluoroethane) and R152a (1,1difluoroethane) were investigated at pressures up to 20 MPa. These pressures reached near-critical and supercritical conditions for the three gas components and produced polymer-gas solutions containing up to 10 wt % gas. The measurements were performed in a sealed highpressure capillary rheometer at 150 and 175C and at shear rates ranging from 1 to 2000/s. Very large reductions in melt viscosity were observed at high gas loading, 10 wt % R152a at 150C reducing the Newtonian viscosity by nearly three orders of magnitude relative to pure PS. The viscosity data for all three PS-gas systems followed ideal viscoelastic scaling, whereby the set of viscosity curves for a polymer-gas system could be scaled to a master curve of reduced viscosity versus reduced shear rate identical to the viscosity curve for the pure polymer. The viscoelastic scaling factors representing the effect of dissolved gas content on rheological behaviour were found to follow roughly the same variation with composition for all three PS gas systems. 20 refs. USA

Accession no.754124 Item 283 Antec ‘99. Volume II. Conference proceedings. New York City, 2nd-6th May 1999, p.2433-5. 012 APPLICATIONS OF FTIR SPECTROSCOPY TO CHARACTERISE POLYMERS PROCESSED WITH SUPERCRITICAL CARBON DIOXIDE Kazarian S G London,Imperial College of Science,Technology & Medicine (SPE) Supercritical CO2 can induce crystallisation of amorphous polymers. Molecular level insight into the microstructures of CO2-processed polymers is needed to form a basis for utilisation and optimisation of supercritical fluid processing of polymeric materials. FTIR spectroscopy is applied to elucidate the morphology and microstructure of polymers processed with supercritical CO2. FTIR spectra of syndiotactic PS show an increased degree of

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crystallinity after being subjected to scCO2. The various crystalline forms induced by CO2 in syndiotactic PS are characterised via FTIR spectra. FTIR spectroscopy is also used to measure the kinetics of CO2-induced crystallisation in these polymers. 19 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.749592 Item 284 Antec ‘99. Volume II. Conference proceedings. New York City, 2nd-6th May 1999, p.2811-5. 012 MORPHOLOGY DEVELOPMENT IN CARBON DIOXIDE ASSISTED POLYMER BLENDING IN BATCH AND CONTINUOUS PROCESSES Elkovitch M D; Lee L J; Tomasko D L Ohio,State University (SPE) The compatibility of individual homopolymers is one of the most important parameters inÁuencing polymer blending. Often blending involves components with vastly different viscosities and interfacial tensions. Supercritical carbon dioxide can be added to polymer melts as a processing aid such that effective polymer blending will occur. A blend system of a high viscosity PMMA and low viscosity PS is analysed. Carbon dioxide has a higher afÀnity for PMMA than for PS. Therefore, a greater plasticising effect will occur for the PMMA than for the PS. The improved results in polymer blending are shown. The morphology development of the polymer blends is analysed in a high-pressure batch mixer and the continuous extrusion process. 13 refs. USA

Accession no.749543 Item 285 Antec ‘99. Volume II. Conference proceedings. New York City, 2nd-6th May 1999, p.2806-10. 012 EXTRUSION OF PE/PS BLENDS WITH SUPERCRITICAL CO2 IN A TWIN-SCREW EXTRUDER AND A TWIN/SINGLE TANDEM SYSTEM Lee M; Tzoganakis C; Park C B Waterloo,University; Toronto,University (SPE) The effects of dissolved supercritical carbon dioxide on the viscosity and morphological properties are investigated for PE, PS and their blends in a twin-screw extruder and a twin/single screw tandem system. The viscosities of the polymer/CO2 and the blend/CO2 solutions wae measured using a wedge die mounted on the twin-screw extruder. The effect of CO2 on the morphology of PE/PS blends is investigated using a twin/single screw tandem system. This system allows for preferential dissolution of the CO2 into the matrix and/or dispersed polymer phase. By introducing devolatilisation to the tandem system, the morphological

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References and Abstracts

behaviours of PE/PS blends are investigated on unfoamed Àlaments. 22 refs. CANADA

Accession no.749542 Item 286 British Plastics and Rubber Oct.1999, p.14-8 WHERE NEXT FOR GAS INJECTION? Coates P Gas injection moulding provides improved surface Ànish, reduced costs, partly through material saving, and improved dimensional stability. Original leading products were TV housings, where gas injection was used to reduce wall thicknesses and improve cosmetic appearance. Pentex has presented a variation on the gas injection theme, “gas in melt”, where carbon dioxide is added to the melt in the injection barrel, passing into solution in the melt as a supercritical Áuid. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.749219

DISPERSION POLYMERISATION OF METHYL METHACRYLATE IN SUPERCRITICAL CARBON DIOXIDE - EVALUATION OF WELL DEFINED FLUORINATED AB BLOCK COPOLYMERS AS SURFACTANTS Hems W P; Yong T-M; van Nunen J L M; Cooper A I; Holmes A B; GrifÀn D A Melville Laboratory; ZENECA Agrochemicals Application of the ‘screened anionic polymerisation’ method to the synthesis of well-defined AB block copolymers derived from methyl methacrylate and fluorinated methacrylate monomers has provided a family of tuneable surfactants for the free radical dispersion polymerisation of methyl methacrylate in supercritical carbon dioxide. PMMA is obtained with excellent conversion and high molecular weight. Block copolymers having higher molecular weight and higher Áuorine contents are superior surfactants, and by systematic evaluation of the parameters in the dispersion polymerisation of methyl methacrylate, discrete polymer particles can be obtained. 30 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.744478 Item 287 Journal of Polymer Science: Polymer Physics Edition 37, No.15, 1st Aug.1999, p.1881-91 IN SITU DRAWING OF HIGH MOLECULAR WEIGHT POLY(ETHYLENE TEREPHTHALATE) IN SUBCRITICAL AND SUPERCRITICAL CO2 Hobbs T; Lesser A J Massachusetts-Amherst,University Amorphous melt-spun poly(ethylene terephthalate) Àbres were subjected to in situ drawing in the presence of subcritical and supercritical carbon dioxide. The mechanical properties and morphological properties were studied in situ and following drawing treatment. Fibres soaked in subcritical carbon dioxide could be drawn to 30 % higher draw ratios compared with Àbres which were cold-drawn, and they had no measurable resistance to deformation until strain hardening occurred. Fibres drawn in supercritical carbon dioxide had a yield response, a signiÀcant decrease in ductility and a signiÀcant difference in post-yield behaviour. The Àbres drawn in subcritical carbon dioxide had slightly lower tensile properties than cold-drawn samples, whilst those drawn under supercritical conditions had much lower tensile properties, attributed to the limited draw ratio. X-ray diffraction studies showed that carbon dioxide treatment enhanced crystalline phase development. 33 refs. USA

Accession no.747616 Item 288 Journal of Materials Chemistry 9, No.7, July 1999, p.1403-7

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Item 289 Journal of Polymer Science: Polymer Chemistry Edition 37, No.14, 15th July 1999, p.2429-37 PREPARATION OF MICRON-SIZE POLYSTYRENE PARTICLES IN SUPERCRITICAL CARBON DIOXIDE Shiho H; Desimone J M JSR Corp.; North Carolina,Chapel Hill University The dispersion polymerisation of styrene in supercritical CO2 utilising poly(1,1-dihydroperÁuorooctyl acrylate) (pFOA) as a polymeric stabiliser is investigated as well as poly(1,1-dihydroperÁuorooctyl methacrylate) (p-FOMA). The resulting high yield of spherical and relatively uniform PS particles with micron-size range (2.9-9.6 mu m) is formed for 40 hrs at 370 bar using various amounts of pFOA and p-FOMA as a stabiliser with good stability until the end of the reaction. The particle diameter is shown to be dependent on the weight percent of added stabiliser. It has been previously reported that p-FOA is not effective for the dispersion polymerisation of styrene as a stabiliser. Here, it is shown that p-FOA can indeed be an effective stabiliser for the dispersion polymerisation of styrene in supercritical CO2, but the pressure necessary to achieve good stability is higher than pressure used previously. This study suggests the possibility that Áuorinated acrylic homopolymers are effective for the dispersion polymerisation of various kinds of monomers as a stabiliser. 30 refs. JAPAN; USA

Accession no.743140

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Item 290 Chemical Week Suppl.161, No.30, 11th Aug.1999, p.s23 USING SUPERCRITICAL FLUIDS TO PROVIDE USEFUL INFORMATION Krukonis V Phasex Corp. The use of supercritical Áuids to provide information on the molecular weight, chemical composition and crystallinity distribution in polyoleÀns, by the analysis of narrow fractions, is discussed. Such data allows process kinetics, reactor performance and catalyst activity to be determined in more detail than ever before, it is claimed. Supercritical Áuids exhibit a pressure-dependent dissolving power in order to extract narrow fractions to a simultaneous level of resolution and fraction amount that is not achievable by other methods, and enables producers of polyoleÀns to meet the increasing performance demands being placed on them to develop applications-speciÀc polymers. USA

Accession no.742794 Item 291 ACS Polymeric Materials Science & Engineering. Volume 80.Conference proceedings. Anaheim, Ca., Spring 1999, p.518-9 VINYL ACETATE DISPERSION POLYMERIZATION IN SUPERCRITICAL CARBON DIOXIDE RindÁeisch F; Becker R; Hergeth W-D Air Products Polymers GmbH & Co.KG; Wacker Polymer Systems GmbH & Co.KG (ACS,Div.of Polymeric Materials Science & Engng.) The dispersion polymerisation of vinyl acetate in supercritical carbon dioxide (SCCD), using a siloxanebased comb-like graft copolymer stabiliser, was studied. The solubility of polyvinyl acetate in vinyl acetateSCCD solutions of various compositions was studied by observing the transparent-cloud transition of the mixtures as the pressure was dropped at various Àxed temperatures. 3 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.741385 Item 292 Polymer Plastics Technology and Engineering 38, No.3, 1999, p.411-31 SEPARATION AND RECOVERY OF NYLON FROM CARPET WASTE USING A SUPERCRITICAL FLUID ANTISOLVENT TECHNIQUE GrifÀth A T; Park Y; Roberts C B Auburn,University The process involves selective dissolution of nylon up to 2.31 wt.% from a model carpet with an 88 wt.%

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liquid formic acid solution at 40C, recovery of nylon powder with supercritical CO2 antisolvent precipitation at pressures between 84 and 125 bar at 40C and recycling of the solvent and antisolvent by Áashing into two phases. Experiments carried out to study the effects of upstream pressure, downstream pressure, nozzle diameter and nylon solution concentration on the particle size and particle size distribution of the nylon powder revealed that these operating parameters had little inÁuence on such properties, indicating the controllability of the process. 19 refs. USA

Accession no.741245 Item 293 Polymer Degradation and Stability 64, No.2, May 1999, p.289-92 DECOMPOSITION OF POLYCARBONATE IN SUBCRITICAL AND SUPERCRITICAL WATER Tagaya H; Katoh K; Kadokawa J; Chiba K Yamagata,University The decomposition reaction of polycarbonate in subcritical and supercritical water was studied. The decomposition products were phenol, bisphenol A, p-isopropenylphenol and p-isopropylphenol at 230C-430C in water. The reactions were accelerated when sodium carbonate was added and the yields of identiÀed products reached 67%, even in the reaction at 300C for 24 h. 12 refs. JAPAN

Accession no.737350 Item 294 Journal of Elastomers and Plastics 31, No.2, April 1999, p.162-79 CONVERSION OF TYRE WASTE USING SUBCRITICAL AND SUPERCRITICAL WATER OXIDATION Park Y; Reaves J T; Curtis C W; Roberts C B Auburn,University The properties designed into tyres that make them strong and chemically resistant also inhibit their ability to be recycled easily. Conventional liquid solvents do not sufficiently dissolve waste tyres and tyre production material for convenient separation. Supercritical water oxidation (SCWO) may provide an alternative solution to this environmental problem. Partial SCWO can be used as a means to partially break down rubber (polymeric) waste materials into lower molecular weight components that could be recovered as a chemical feedstock. The feasibility of converting waste material from tyre production into useful products is explored. Batch SCWO studies illustrate the ability to efÀciently break down the waste tyre production material into a range of lower molecular weight organics for possible reuse depending on reaction conditions. Furthermore, a semi-continuous process is developed and preliminary results are presented. Destruction efÀciencies of greater than 0.9 are obtained

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References and Abstracts

in all runs regardless of reactor type. The results show SCWO to be a promising remediation alternative to the waste tyre problem. 32 refs. USA

Accession no.732310 Item 295 Industrial and Engineering Chemistry Research 38, No.4, April 1999, p.1391-5 DECOMPOSITION OF PREPOLYMERS AND MOULDING MATERIALS OF PHENOL RESIN IN SUBCRITICAL AND SUPERCRITICAL WATER UNDER AN ARGON ATMOSPHERE Suzuki Y; Tagaya H; Asou T; Kadokawa J; Chiba K Yamagata,University; Sumitomo Bakelite Co.Ltd. Seven phenol resin prepolymers and moulding materials were decomposed into their monomers by reactions at 523-703K under an argon atmosphere in subcritical and supercritical water. The decomposition reactions were accelerated by the addition of sodium carbonate. 28 refs. JAPAN

Accession no.732130 Item 296 Polymer Preprints. Volume 40. Number 1. March 1999. Conference proceedings. Boston, Ma., March 1999, p.228-9. 012 METAL-POLYMER COMPOSITES IN SUPERCRITICAL FLUID CARBON DIOXIDE Rajagopalan P; McCarthy T J Amherst,Massachusetts University (ACS,Div.of Polymer Chemistry) The synthesis of metal-polymer nanocomposites in supercritical Áuid (SCF) carbon dioxide has recently been reported. Supercritical Áuids have very attractive properties enabling them to be viable reaction media, some of these properties include gas-like diffusivity combined with a liquid-like density and a tunable solvent strength. Previously, an organo-platinum complex was dissolved in SCF CO2 under a given set of conditions and then infused within a polymer substrate (PTFE). Upon further reduction of the organoplatinum complex, nanoscale platinum particles were deposited through the entire polymer substrate. The infusion of an additive (dissolved in SCF CO2) into a SCF CO2 swollen polymer substrate has been studied. The additive was iron acetylacetonate, (Fe(acac)3), and LDPE was chosen as the polymer substrate. Fe(acac)3 has been reported to impart Áame retardant properties to polymeric substrates, thus satisfying another objective which is to observe thermal degradation properties of metal/polymer composites. Fe(acac)3, in addition to being a Áame retardant additive, is also a precursor to iron oxide. Iron oxide, a dehydrogenation catalyst, can promote char formation during thermal degradation of polymers, thus enhancing their Àre retardant properties. It is demonstrated that HDPE-Fe(acac)3 composites can

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be formed in SCF CO2. Fe(acac)3 is deposited closer to the surface of the LDPE plaques. In general, increasing infusion temperature increases concentration of Fe(acac)3 deposited within LDPE. The thermal degradation of LDPE-Fe(acac)3 composites in the 400-450 deg.C range is slower in comparison to virgin LDPE. 13 refs. USA

Accession no.730044 Item 297 ACS Polymeric Materials Science & Engineering. Volume 74. Conference proceedings. New Orleans, La., Spring 1996, p.260-1. 012 EFFECT OF ADDED HELIUM ON PARTICLE SIZE AND PARTICLE SIZE DISTRIBUTION OF DISPERSION POLYMERISATIONS OF METHYL METHACRYLATE IN SUPERCRITICAL CARBON DIOXIDE Hsaio Y-L; DeSimone J M North Carolina,University (ACS,Div.of Polymeric Materials Science & Engng.) The synthesis of spherical polymers particles with a range of diameters has been an active area of research due to the wide variety of applications for such materials. Practical use of these particles includes standards for the determination of pore size and the efÀciency of Àlters, column packing material for chromatographic separation, support materials for biochemicals, toner, cosmetics, drug delivery vehicles, etc. Control of particle size and uniformity has been a major area of interest. It is particularly challenging to prepare monodisperse polymer particles in the micron size range. Dispersion polymerisation is one of the best synthetic methods for the preparation of uniform particles in the micron range. As a means to control particle size and particle size distribution, a number of investigations has focused on the inÁuence of the reaction initiator, monomer and stabiliser concentrations; reaction temperature, and cosolvents. These studies concluded that the nucleation period plays an important role in determining particle size characteristics. One of the factors that strongly inÁuence the nucleation period is the solvency of the reaction medium. There are numerous examples using cosolvents to manipulate the particle size and particle size distribution through changing the solvency of the reaction media. It is demonstrated that it is possible to control the particle size characteristics of the dispersion polymerisation of methyl methacrylate in supercritical CO2 by varying the amount of a gaseous cosolvent - helium. 31 refs. USA

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Item 298 ACS Polymeric Materials Science & Engineering. Volume 74. Conference proceedings. New Orleans, La., Spring 1996, p.256-7. 012 SYNTHESIS OF POLY(2,6DIMETHYLPHENYLENE OXIDE) IN CARBON DIOXIDE Kapellen K K; Mistele C D; DeSimone J M North Carolina,University (ACS,Div.of Polymeric Materials Science & Engng.) The utilisation of CO2 as a medium for polymerisation reactions has attracted signiÀcant interest. For example, it has been successfully employed as a continuous phase in homogeneous free radical polymerisations, heterogeneous free radical polymerisations, as well as cationic polymerisations and ring-opening methathesis polymerisations. The advantages of carbon dioxide as a reaction medium include the case with which the polymer can be separated from the reaction medium and the powdery form in which the polymer can be obtained. Furthermore, the density and the viscosity of carbon dioxide can be tuned over a large range due to the compressibility of CO2, particularly in the supercritical phase. PPOs are mainly synthesised via the oxidative coupling polymerisation of 2,6-di- and 2,3,6tri-substituted phenols. The most common of these processes is performed using 2,6-dimethylphenol as monomer and a catalyst system which includes a copper halide, an amine and oxygen. Oxygen is usually passed through the reaction solution during the course of the reaction. All of the processes are solvent intensive as they are performed in organic solvents like toluene, benzene, halogenated hydrocarbons, dimethyl sulphoxide or in biphasic systems and are precipitated into a nonsolvent such as methanol to isolate the polymer. The use of carbon dioxide as the reaction medium for the synthesis of PPOs would eliminate the need for using organic solvents in the manufacture of this commercially important polymer. 10 refs. USA

Accession no.724893 Item 299 ACS Polymeric Materials Science & Engineering. Volume 74. Conference proceedings. New Orleans, La., Spring 1996, p.254-5. 012 CATIONIC POLYMERISATION OF OXETANES IN LIQUID CARBON DIOXIDE Kanameneni S; Desimone J M North Carolina,University (ACS,Div.of Polymeric Materials Science & Engng.) Cationic ring opening polymerisations of cyclic ethers are usually carried out in chlorinated organic solvents such as methylene chloride (CH2Cl2). Increasing concern regarding the dissemination of volatile organic compounds prompted chemical industries to use environmentally sound practices in the manufacture and processing of products. Carbon dioxide (CO2) has low dielectric constant, and low viscosity. It is a non-toxic, inexpensive

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and environmentally sound reaction medium. Previously it has been shown that supercritical carbon dioxide is an excellent solvent to conduct free-radical chain reactions and ring-opening metathesis reactions, etc. The cationic polymerisation of vinyl and cyclic ethers in CO2 has also recently been demonstrated, using boron triÁuoridetetrahydrofuran as the initiating system. The cationic ring opening polymerisation of oxetanes in liquid carbon dioxide as the solvent/dispersing medium are reported. The goal is to use the bifunctional initiator p-DCC/AgSbF6 for the homopolymerisation of oxetane monomers such as bis(ethoxymethyl)oxetane (BEMO) and ethoxymethyl methyl oxetane (EMMO) in CO2 and to eventually make triblock thermoplastic elastomers in CO2. The results of the cationic polymerisation of oxetanes using a bifunctional initiator in liquid CO2 are described. 12 refs. USA

Accession no.724892 Item 300 ACS Polymeric Materials Science & Engineering. Volume 74. Conference proceedings. New Orleans, La., Spring 1996, p.248-9. 012 SYNTHESIS OF POLYESTERS IN SUPERCRITICAL CARBON DIOXIDE Burke A L C; Maier G; DeSimone J M North Carolina,University (ACS,Div.of Polymeric Materials Science & Engng.) The melt phase polymerisation of many polyesters may be accomplished by the condensation of a variety of difunctional monomer units, releasing a small molecule condensate as a by-product of either a transesteriÀcation or a melt acidolysis reaction. Removal of this by-product is an essential force in driving the polymerisation reaction. The efÀciency of supercritical Áuid extraction methods to solubilise condensation byproducts for subsequent removal from the reaction is investigated. Polyesters suitable for supercritical fluid extraction encompass a variety of aliphatic and aromatic species, including polymers with potential applications as powder coatings. The synthesis of PETP using supercritical Áuid extraction (SCFE) is introduced. 9 refs. USA

Accession no.724889 Item 301 ACS Polymeric Materials Science & Engineering. Volume 74. Conference proceedings. New Orleans, La., Spring 1996, p.246-7. 012 POLYMER MODIFICATION IN SUPERCRITICAL CARBON DIOXIDE Kerschner J L; Jurelle S H; Harris R Unilever Research (ACS,Div.of Polymeric Materials Science & Engng.) With many polymers, the technique of compounding or the infusion of modiÀers into the polymer matrix requires

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References and Abstracts

procedures involving mixing or kneading the modiÀer with the polymer with the application or generation of heat which is often detrimental to the stability of the modiÀer itself or can even degrade the polymer. As an alternative method, dissolution of a polymer in a solvent followed by addition of the modiÀer can be successful, but exhaustive removal of the solvent is often difÀcult, and the residual solvent present in the modiÀed polymer can affect the intended use of the polymer and can present environmental and safety problems for the end product. Supercritical Áuids offer an inexpensive, non-toxic, nonÁammable alternative to typical organic solvents and these Áuids have the ability to swell and plasticise some polymers, resulting in a signiÀcant reduction of the glass transition temperature of the polymer. The adsorption of chemically reactive modiÀers/catalysts into the polymer is described. Under modiÀcation conditions, the modiÀers react with different polymer pendant groups adding new chemical functionality to the polymeric material. For example, in this process, long chain hydrophobic groups could be added to hydrophilic polymers resulting in new materials with distinctly different chemical and physical properties. 6 refs. USA

Accession no.724888 Item 302 ACS Polymeric Materials Science & Engineering. Volume 74. Conference proceedings. New Orleans, La., Spring 1996, p.2331-2. 012 HIGH-PRESSURE MISCIBILITY AND EXTRACTION OF POLYMERIC COATINGS AND HOT-MELT ADHESIVES WITH CARBON DIOXIDE AND PENTANE MIXTURES Kiran E; Malki K; Pohler H Maine,University (ACS,Div.of Polymeric Materials Science & Engng.) More than 150 million tons of municipal solid waste is generated each year in the USA; of this, paper and paper board accounts for 40% and plastics account for 8% by weight. A major source of waste is packaging materials (about 32%) of which paper and paper board, and plastics represent 18 and 3 %, respectively. The major plastic components found in the municipal solid waste are LDPE, HDPE, PS, PP and PETP. A variety of polymers is also found in paper wastes as they are used as barrier film coatings, hot-melt adhesives, pressure-sensitive adhesives, laser printer and photocopier toner inks and binders in paper coatings. These polymeric constituents often represent difÀculties in recycling of reclamation of secondary Àbres from waste paper. The University of Maine has been involved in applications of supercritical Áuids in the polymers, pulp and paper and forest products industries. Some recent activity has been focused on extraction of polymeric constituents from mixed plastics and/or from paper/polymer composites. For this purpose it has generated a fundamental data base on the miscibility

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of model polymers in selected fluid systems, and is conducting extraction studies on both simulated and real paper/plastic waste samples. The miscibility and extraction of selected polymers using carbon dioxide and alkane mixtures are described. 6 refs. USA

Accession no.724880 Item 303 ACS Polymeric Materials Science & Engineering. Volume 74. Conference proceedings. New Orleans, La., Spring 1996, p.230. 012 FORMATION OF MICROCELLULAR POLYMERIC MATERIALS VIA POLYMERISATION IN CARBON DIOXIDE Parks K; Sparacio D; Beckman E J Pittsburgh,University (ACS,Div.of Polymeric Materials Science & Engng.) Microcellular materials have been produced via phase separation in a liquid solution, via gas expansion in molten polymers and via combinations of both approaches. Phase separation can be accomplished via a temperature quench, pressure quench or the addition of a non-solvent to a single phase polymer-solvent mixture. Phase separation can also be induced by an increase in molecular weight or crosslink density, such as in the polymerisation of ion exchange resin systems in solution. While the two gas expansion techniques produce what is considered to be macrocellular foam, it has been shown that when a polymer sample is saturated with gas, then rapidly heated to a point above the glass transition, a microcellular material is produced. The formation of microcellular materials via generation of a PU network in carbon dioxide, followed by solvent (CO2) removal has been investigated. It has been shown that the PU precursors, polyols and isocyanates, are miscible with CO2 above certain threshold pressures. The polymerisation of the precursors can be conducted under conditions where the system is initially a single homogeneous phase. Here, the reaction pressure, type of isocyanate reacted with a particular polyol blend, ratio of diol to crosslinker in the polyol blend, reaction temperature and foaming agent are varied. Bulk densities, cell sizes and cell densities of the resultant foams are measured. It is examined how the mechanism for phase separation affects the pore size of the foams. There is a variety of possible mechanisms for introducing pores in a polymer/solvent mixture, several of which are accessible to this system. USA

Accession no.724879

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Item 304 ACS Polymeric Materials Science & Engineering. Volume 74. Conference proceedings. New Orleans, La., Spring 1996, p.228-9. 012 POLYMER STABILISED EMULSIONS IN SUPERCRITICAL CARBON DIOXIDE O’Neill M L; Yates M Z; Johnston K P; Wilkinson S P; DeSimone J M Texas,University at Austin; Air Products & Chemicals Corp.; North Carolina,University (ACS,Div.of Polymeric Materials Science & Engng.) Traditional supercritical fluid reaction and separation processes require that the target species be soluble in the SCI phase, yet few non-volatile species are soluble. SCF technology could be expanded markedly with the use of surfactants in heterogeneous processes, as reviewed recently for hydrophilic dispersed phases. Recently, a key breakthrough has been the dispersion of lipophilic phases within CO2. Supercritical Áuid (SCF) carbon dioxide (Tc=31 deg.C, Pc = 73.8 bar) is an attractive alternative to liquid and SCF organic solvents because it is non-toxic, nonÁammable, inexpensive and environmentally benign compared with organic solvents. However, because of its very low dielectric constant, E, and polarisability per volume, alpha/v, CO2 is a poor solvent for most non-volatile lipophilic or hydrophilic solutes, i.e. water. Consequently, it may be considered a third type of condensed phase. The appropriate choice of surfactant affords an interesting opportunity to disperse either lipophilic or hydrophilic phases into CO2 in the form of microemulsions, emulsions and latexes. Recently dispersion polymerisation has been performed successfully in SCF CO2 with surfactant stabilisers. Poly(l,1-dihydroperÁuorooctyl acrylate) poly(FOA) acts as a stabiliser in the dispersion polymerisation of methyl methacrylate. High molecular weight PMMA latex particles are produced with diameters from 1.55 to 2.86 mm. Models of emulsions and latexes in liquids are applied to SCF emulsions to better understand stabilisation mechanisms for polymer surfactants, in particular poly(FOA). 12 refs. USA

Accession no.724878 Item 305 ACS Polymeric Materials Science & Engineering. Volume 74. Conference proceedings. New Orleans, La., Spring 1996, p.1835-. 012 PLASTICISATION OF POLYMER MELTS WITH DENSE OR SUPERCRITICAL CO2 Kwag C; Gerhadt L J; Khan V; Gulari E; Manke C W Wayne State,University (ACS,Div.of Polymeric Materials Science & Engng.) Supercritical gases (SCGs) are of great interest as plasticisers for polymer processing applications such as composites, foams and paints, where an environmentally benign supercritical gas such as carbon dioxide can replace organic solvents or CFC blowing agents, thereby reducing or eliminating the emissions of VOCs or ozone-depleting components. Moreover, SCGs

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have important performance advantages over conventional organic solvents for applications where the viscosity of a thermoplastic resin must be reduced for more efÀcient processing. Like organic solvents, SCGs act to reduce viscosity by bulk dilution of the density of polymer chain segments within the melt. However, SCUs can also contribute signiÀcant free volume to the polymer melt, resulting in signiÀcant reductions in melt viscosity beyond those that can be achieved by chain dilution alone. The rheological behaviour of high molecular weight polydimethylsiloxane (PDMS) and PS melts plasticised with dissolved carbon dioxide are examined. Viscosity curves for both systems are measured with a pressurised capillary rheometer to characterise the melt viscosity as a function of shear rate and carbon dioxide content. An equation-of-state (EOS) model for the density of polymer-CO2 solutions is combined with a free-volume rheological theory to predict the compositiondependent shift factors directly. 3 refs. USA

Accession no.724855 Item 306 ACS Polymeric Materials Science & Engineering. Volume 74. Conference proceedings. New Orleans, La., Spring 1996, p.178-9. 012 SOLUBILITY OF POLYMERS AND COPOLYMERS IN SUPERCRITICAL CO2: WHY HIGH PRESSURES AND TEMPERATURES ARE NEEDED RindÁeisch F; DiNoia T; McHugh M A Johns Hopkins University (ACS,Div.of Polymeric Materials Science & Engng.) Carbon dioxide has been touted as the solvent of choice for many industrial applications because of its attractive attributes, e.g., it is environmentally benign, non-hazardous, and very inexpensive. CO2 has a modest critical temperature and pressure and it is much more dense than most supercritical Áuids which suggests that at temperatures slightly above room temperature it should be possible to obtain liquid-like densities, and by implication, liquid-like solvent characteristics. It has been shown that CO2 at or near room temperature and at pressures typically below 600 bar can be used to solubilise a variety of polymeric oils, such as many polydimethyl and polydiphenyl silicones, perÁuoroalkylpolyethers and chloro- and bromotriÁuoroethylene polymer. CO2 can also solubilise very low molecular weight, slightly polar polymers, such as PS, with molecular weights below 1,000. It has been demonstrated that CO2 can dissolve polymers comprised of long-chain side groups of Áuorinated alkyl acrylates. High molecular weight block copolymers have also been synthesised that are CO2 soluble. However, most polymers do not dissolve in CO2, regardless of temperature and pressure. Experimental cloud-point data are presented for a number of polymers and copolymers in CO2. The polymers of interest include polyacrylates, polymethacrylates, PE, and fluorinated copolymers. The cloud-point behaviour of these polymers in

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References and Abstracts

CO2 are compared to similar behaviour in other supercritical Áuids that exhibit certain physicochemical properties similar to CO2. 16 refs. USA

Accession no.724852 Item 307 ACS Polymeric Materials Science & Engineering. Volume 74. Conference proceedings. New Orleans, La., Spring 1996, p.433-4. 012 FREE RADICAL DISPERSION POLYMERISATIONS IN LIQUID CARBON DIOXIDE USING A REDOX INITIATOR Dessipri E; Hsiao Y-L; Mathes A C J; Shaffer K A; DeSimone J M North Carolina,University (ACS,Div.of Polymeric Materials Science & Engng.) Supercritical carbon dioxide has proved to be an excellent medium for the performance of free radical polymerisation reactions because of obvious environmental and toxicity advantages afforded by CO2 combined with its inertness towards free radicals, low viscosity and the ability to obtain high initiator efÀciencies. The use of carbon dioxide for homogeneous polymerisations is rather limited because of the insolubility of most common polymers in CO2. On the other hand, dispersion polymerisation of a variety of oleÀnic monomers can be carried out in carbon dioxide to yield polymers in the form of free Áowing powders made of uniform spherical particles. When considering dispersion polymerisations at lower temperatures, two issues are of prime concern: the kinetics of polymerisation should allow for the formation of high molecular weight materials at high yields and within reasonable reaction times, and the stabilisers used must be effective in liquid CO2. The successful polymerisation of methyl methacrylate at 30 deg.C using a low temperature initiator, 2,2’-azobis(4-methoxy-2,4-dimethyl valeronitrile), and a PDMS macromonomer as stabiliser in liquid C02. One system that can be used with organic solvents is the combination of BPC N,N-dialkylanilines. The rate of BPO decomposition is reported to increase by at least three orders of magnitude in the presence of dialkylanilines. The use of this initiating system for the dispersion polymerisation of methyl methacrylate in carbon dioxide using various polymeric steric stabilisers is described. 13 refs. USA

Accession no.724785 Item 308 ACS Polymeric Materials Science & Engineering. Volume 74. Conference proceedings. New Orleans, La., Spring 1996, p.431-2. 012 ZINC CATALYSTS FOR THE COPOLYMERISATION OF EPOXIDES AND CARBON DIOXIDE TO POLYCARBONATES Darensburg D J Texas A & M University

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(ACS,Div.of Polymeric Materials Science & Engng.) Supercritical CO2 has been found to be a suitable substitute for organic solvents in polymerisation reactions in which CO2 is also a reactant. Furthermore, the use of CO2 (at pressures greater than 700 psi) results in higher selectivity for polycarbonate versus polyether formation. In addition, the advantage of using supercritical carbon dioxide is that it is as effective a solvent as inert organic solvents, such as methylene chloride, for the copolymerisation, yet it is environmentally benign. 7 refs. USA

Accession no.724784 Item 309 ACS Polymeric Materials Science & Engineering. Volume 74. Conference proceedings. New Orleans, La., Spring 1996, p.430. 012 SUPERCRITICAL CO2 AS A MONOMER AND SOLVENT: POLYCARBONATES FROM CYCLOHEXENE OXIDE AND CARBON DIOXIDE Costello C A; Berluche E; Han S J; Sysyn D A; Super M S; Beckman E J Exxon Research & Engineering Co.; Pittsburgh,University (ACS,Div.of Polymeric Materials Science & Engng.) Supercritical CO2 has received much attention in extraction processes and in fractionation of polymers. Recently, there has been much interest in replacing organic polymerisation solvents with supercritical CO2 in various types of polymerisation processes due to the low toxicity CO2 possesses. Success has been realised in solution polymerisation, dispersion polymerisation and inverse emulsion polymerisation. There is interest in using supercritical CO2 as a monomer as well as a polymerisation solvent, thus providing a route to polymers using an inexpensive C1 feed. The concept of using supercritical CO2 as a reactant and solvent has been demonstrated in small molecule organic chemistry. The application of CO2 as a monomer in polymerisation has been reviewed. Most of the reactions reported are run at subcritical conditions and employ organic solvents in addition to CO2. Recent work on Ni(0)-catalysed alternating cycloaddition copolymerisation of acyclic diynes with CO2 also employs additional organic solvent. The alternating copolymerisation of CO2 and epoxides using zinc-based catalysts, which produces a polycarbonate with some ether linkages, is investigated. Cyclic carbonate is also produced in appreciable amounts. The development of a CO2-soluble Zn catalyst for cyclohexene oxide/CO2 copolymerisation in the absence of any additional organic solvents is reported, together with the pressure and temperature dependence on the conversion and selectivity of the reaction. 12 refs. USA

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References and Abstracts

Item 310 ACS Polymeric Materials Science & Engineering. Volume 74. Conference proceedings. New Orleans, La., Spring 1996, p.428-9. 012 SYNTHESIS OF TETRAFLUOROETHYLENEBASED, NON-AQUEOUS FLUOROPOLYMERS IN SUPERCRITICAL CARBON DIOXIDE Romack T J; DeSimone J M North Carolina,University (ACS,Div.of Polymeric Materials Science & Engng.) Carbon dioxide is an excellent, environmentally responsible alternative to CFCs in which to conduct nonaqueous polymerisations of ÁuorooleÀns. Copolymers of tetrafluoroethylene and perfluoro(propyl vinyl ether), as well as copolymers of tetrafluoroethylene and hexaÁuoropropylene are synthesised in high yields employing bis(perÁuoro-2-propoxy propionyl) peroxide as a free radical initiator in supercritical carbon dioxide. For TFE/PPVE copolymers, molecular weights achieved are high and FTIR analysis indicates the successful elimination of deleterious end groups. Copolymers of HFP with TFE show good incorporation and reasonable yields. In light of the impending ban on CFCs, and the improved physical attributes of these materials, the polymerisation of ÁuorooleÀns in such an environmentally responsible medium may well prove to be a viable alternative to conventional solvents for the manufacture of non-aqueous Áuoropolymers. 28 refs. USA

Accession no.724782 Item 311 ACS Polymeric Materials Science & Engineering. Volume 74. Conference proceedings. New Orleans, La., Spring 1996, p.427. 012 SYNTHESIS OF POLYACRYLIC ACIDS IN SUPER-CRITICAL CARBON DIOXIDE Dada E; Lau W; Merritt R F; Paik Y H; Swift G Rohm & Haas Co. (ACS,Div.of Polymeric Materials Science & Engng.) Polyacrylic acids are widely used in many applications depending on their molecular weight. High molecular weight polymers are usually prepared at low solids because of viscosity limitations or as dispersions in organic solvents; the former requires the use and transport of huge volumes of water and the latter careful control of solvent emissions. Low molecular weight polymers may also be prepared in water or organic solvents and these have the additional potential environmental issue of using high organic initiator levels and/or chain transfer agents, such as mercaptans, to control molecular weight. Should solid polymer isolation be required, removal of solvent and/or water is energy intensive which indirectly impacts the environment, and solvent emissions need to be controlled. There are quite obviously opportunities to develop improved free-radical addition polymerisations for acrylic acid which are free from these potential environmental

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issues, with good molecular weight control over a wide range, and with the ability to readily isolate solid polymeric products. Preliminary investigations suggest that polymerisations in super-critical carbon dioxide may satisfy all these requirements. 5 refs. USA

Accession no.724781 Item 312 ACS Polymeric Materials Science & Engineering. Volume 74. Conference proceedings. New Orleans, La., Spring 1996, p.404-5. 012 LIVING FREE RADICAL POLYMERISATIONS IN SUPERCRITICAL CARBON DIOXIDE Odell P G; Hamer G K Xerox Corp. (ACS,Div.of Polymeric Materials Science & Engng.) Living free radical polymerisation, employing the concept of reversible termination, using a nitroxide stable free radical, such as TEMPO, has been studied. This system can provide polymers of narrow polydispersity via controlled stepwise growth. The molar mass of these polymers can vary from low molecular weight oligomers through to high molecular weight polymers. This approach has been successfully applied not only to bulk homopolymerisation and block copolymerisation, but also suspension copolymerisation and aqueous polymerisations. Recent efforts employing stable free radical polymerisation (SFRP) techniques in supercritical carbon dioxide are described. One valuable attribute of a ‘living’ polymerisation is the potential for forming well-deÀned block copolymers. Supercritical Áuid technology provides additional beneÀt to SFRP as block copolymers may be obtained in the absence of conventional solvents and without any additional puriÀcation beyond the extraction of unreacted monomer of an earlier block. Furthermore, the plasticisation of polymers by CO2(sc) may also enhance the reactivity of the diffusion controlled process. Lastly, the different kinetics of free radical processes in CO2 due to its very low dielectric constant may provide insight or advantage to the SFRP process. Concurrently, the study of the repetitive homolytic cleavage of the nitroxide-polymer chain end bond may offer a broader understanding of free radical processes in supercritical carbon dioxide. 8 refs. CANADA

Accession no.724768 Item 313 Patent Number: US 5766637 A 19980616 MICROENCAPSULATION PROCESS USING SUPERCRITICAL FLUIDS Shine A D; Gelb J Delaware,University The present invention comprises a method for microencapsulating a core material comprising: (a) mixing a core material with an encapsulating polymer,

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References and Abstracts

(b) supplying a supercritical Áuid capable of swelling the polymer to the mixture under a temperature and a pressure sufÀcient to maintain the Áuid in a supercritical state, (c) allowing the supercritical Áuid to penetrate and liquefy the polymer while maintaining temperature and pressure sufÀcient to maintain the Áuid in a supercritical state, and (d) rapidly releasing the pressure to solidify the polymer around the core material to form a microcapsule. This method requires neither that the polymer nor core materials to be soluble in the supercritical Áuid and can be used to rapidly and efÀciently microencapsulate a variety of materials for a variety of applications. USA

Accession no.723418 Item 314 Journal of Polymer Science : Polymer Physics Edition 37, No.6, March 1999, p.553-60 HDPE FRACTIONATION WITH SUPERCRITICAL PROPANE Britto L J D; Soares J B P; Penlidis A; Krukonis V Waterloo,University; Phasex Corp. Supercritical propane was used to fractionate HDPE by molecular weight and short chain branching. The use of this solvent to obtain fractions of uniform molecular weight or chemical composition without generating hazardous solvent waste is discussed. 20 refs. CANADA; USA

Accession no.723319 Item 315 Journal of the Textile Institute - Part 1: Fibre Science and Textile Technology 89, No.4, 1998, p.657-68 DYEING OF POLYOLEFIN FIBRES IN SUPERCRITICAL CARBON DIOXIDE. II. THE INFLUENCE OF DYE STRUCTURE ON THE DYEING OF FABRICS AND ON FASTNESS PROPERTIES Bach E; Cleve E; Schollmeyer E Deutsches Textilforschungszentrum Nord-West eV Dyeing of gel-spun PE Àbres of low and high draw ratio, PP Àbres, and PETP Àbres was carried out in supercritical carbon dioxide at 280 bar and in water under optimum dyeing conditions at 120 C. The inÁuence of the chemical structure of different disperse azo and anthraquinone dyes on the dye uptake and also on the washing-, sublimation-, and light-fastness of the Àbres was presented. 23 refs.

89, No.4, 1998, p.647-56 DYEING OF POLYOLEFIN FIBRES IN SUPERCRITICAL CARBON DIOXIDE. I. THERMOMECHANICAL PROPERTIES OF POLYOLEFIN FIBRES AFTER TREATMENT IN CARBON DIOXIDE UNDER DYEING CONDITIONS Bach E; Cleve E; Schollmeyer E Deutsches Textilforschungszentrum Nord-West eV Viscoelastic properties of gel-spun PE and PP Àbres after treatment in supercritical carbon dioxide at 280 bar were examined to determine the optimum conditions for dyeing without causing Àbre damage. Melting, shrinkage and thermomechanical properties of PE and PP Àbres after treatment in carbon dioxide was presented. 18 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.721405 Item 317 ACS Polymeric Materials Science & Engineering, Spring Meeting 1998. Volume 78. Conference proceedings. Dallas, Tx., Spring 1998, p.155. 012 DECOMPOSITION OF MODEL COMPOUNDS AND PREPOLYMERS OF PHENOL RESIN WASTE WITH SUPERCRITICAL WATER Tagaya H; Suzuki Y; Karasu M; Kadokawa J; Chiba K Yamagata,University (ACS,Div.of Polymeric Materials Science & Engng.) Phenol resin is known to be a thermosetting thermally stable resin. It has been found that model compounds of phenol resin wastes such as p- and o-bis(hydroxyphenyl) methanes are decomposed into phenol and cresol easily by reaction with supercritical water. However, condensation reaction giving trimer is also conÀrmed. By the addition of small amounts of NaCl, product yield increases, however basic compounds are more effective additives than NaCl. The chemical participation of water is suggested from the structure of reaction intermediates which are obtained by the reaction at mild conditions. Prepolymers of phenol resin are also decomposed into their monomers even by the reaction at below critical temperature of water. Addition of basic compounds are also effective and yields of monomers are greater than 90% in the case of prepolymers of p-isopropylphenol resin. This abstract includes all the information contained in the original article. JAPAN

Accession no.719085

EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.721406 Item 316 Journal of the Textile Institute - Part 1: Fibre Science and Textile Technology

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References and Abstracts

Item 318 ACS Polymeric Materials Science & Engineering, Spring Meeting 1998. Volume 78. Conference proceedings. Dallas, Tx., Spring 1998, p.155. 012 CHEMICAL RECYCLING OF PLASTIC MOULDING MATERIALS IN SUB-CRITICAL AND SUPERCRITICAL WATER Katoh K; Suzuki Y; Tagaya H; Karasu M; Kadokawa J; Chiba K Yamagata,University (ACS,Div.of Polymeric Materials Science & Engng.) In Japan, more than 80% of plastic wastes are landÀlled and incinerated. Chemical recycling is essential to protect the environment issue and proceed effective use of carbon resources. To establish chemical recycling processes of polymer waste, moulding material (phenol resin and polycarbonate) decomposition in supercritical water (SCW) and in sub-SCW is studied. Phenol resin moulding materials are decomposed into phenol and cresol mainly in SCW. Polycarbonate moulding materials decompose in sub-SCW at around 300 deg.C; decomposition reaction with additive gives high yields. This abstract includes all the information contained in the original article. JAPAN

Accession no.719083 Item 319 Polymer Engineering and Science 38, No.12, Dec.1998, p.2055-62 COMPRESSIVE BEHAVIOUR OF MICROCELLULAR POLYSTYRENE FOAMS PROCESSED IN SUPERCRITICAL CARBON DIOXIDE Arora K A; Lesser A J; McCarthy T J Massachusetts,University Microcellular PS foams were prepared using supercritical carbon dioxide as the foaming agent. The cellular structures from this process are shown to have a signiÀcant effect on the corresponding mechanical properties of the foams. Compression tests were performed on highly expanded foams having oriented, anisotropic cells. For these materials an anisotropic foam model can be used to predict the effect of cell size and shape on the compressive yield stress. Beyond yield, the foams deformed heterogeneously under a constant stress. Microstructural investigations of the heterogeneous deformation indicate that the dominant mechanisms are progressive microcellular collapse followed by foam densification. The phenomenon is compared to the development of a stable neck commonly observed in polymers subjected to uniaxial tension, and a model that describes the densiÀcation process is formulated from simple energy balance considerations. Yield stress and collapse stress data are shown for various foam densities and cell dimensions. 25 refs. USA

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Item 320 Macromolecular Symposia Vol.135, Dec.1998, p.205-14 CONVERSION OF POLYMERS AND BIOMASS TO CHEMICAL INTERMEDIATES WITH SUPERCRITICAL WATER Arai K Tohoku,University Results are reported of recent studies on the conversion of polymers and biomass to chemical intermediates and monomers by using subcritical and supercritical water as the reaction solvent. The reactions of cellulose in supercritical water are shown to be rapid and to proceed to 100% conversion with no char formation, these reactions showing a signiÀcant increase in hydrolysis products and lower pyrolysis products when compared with reactions in subcritical water. There is also a jump in the reaction rate of cellulose at the critical temp. of water. If the methods used for cellulose are applied to synthetic polymers, such as PETP or polyamide, high liquid yields can be achieved although the reactions require about 10 min for complete conversion. The reason for this is the heterogeneous nature of the reaction system. For PE, higher yields of short-chain hydrocarbons, higher alkene/alkane ratios and higher conversions are obtained in supercritical water than those obtained by pyrolysis. 18 refs. (IUPAC, 38th Microsymposium on Recycling of Polymers, Prague, July 1997) JAPAN

Accession no.715499 Item 321 Patent Number: US 5780565 A 19980714 SUPERATMOSPHERIC REACTION Clough R S; Senger C L; Gozum J E Minnesota Mining & Mfg.Co. A polymerisation process is carried out in a Áuid held under superatmospheric conditions such that the Áuid is a liquid or a supercritical Áuid, such as carbon dioxide, a hydroÁuorocarbon, perÁuorocarbon or mixture thereof. The polymers obtained are insoluble in a reaction mixture, which was homogeneous before the polymer began to form. A dispersing agent in the polymerising system allows a kinetically stable dispersion of the polymer to be formed therein. USA

Accession no.705587 Item 322 Supercritical Fluid Technology. Conference proceedings. Birmingham, 15th-17th Sept.1997, paper 10. 91141T DESIGN OF INDUSTRIAL PLANT SPRAY COATING Mandel F S Ferro Corp.

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References and Abstracts

(Royal Society of Chemistry,Process Technology Group; SCI Separation Science & Technology Group; SCI Process Engineering Group; Environmental Technology Best Practice Programme) The employment of supercritical Áuids as a mixing aid for the manufacture of powder coatings and other products characterised by highly loaded polymer systems is being commercialised. Beneficial properties and enhanced product performance has been attained via the production of highly loaded polymer systems using supercritical carbon dioxide, an environmentally friendly solvent. The product beneÀts include enhanced electrostatic properties, high levels of porosity, strong colour adherence, excellent molecular weight control and the formation of particles via atomisation. The manufacturing techniques for the mixing of polymer formulations via Supercritical Fluid assisted manufacturing have been reviewed. Issues concerning scale up from laboratory to pilot plant to commercial facility have been addressed. This abstract includes all the information contained in the original article. USA

Accession no.704083 Item 323 Supercritical Fluid Technology. Conference proceedings. Birmingham, 15th-17th Sept.1997, paper 9. 91141T POLYMER SYNTHESIS IN LIQUID/ SUPERCRITICAL CARBON DIOXIDE Cooper A I Cambridge,University (Royal Society of Chemistry,Process Technology Group; SCI Separation Science & Technology Group; SCI Process Engineering Group; Environmental Technology Best Practice Programme) The use of carbon dioxide as an inert solvent has emerged recently as an important development in polymer chemistry. The past few years have seen major advances in the synthesis of a variety of Áuorinated and non-Áuorinated polymeric materials in carbon dioxide. Synthetic studies that deÀne the scope of this approach have been reviewed, including homogeneous polymerisation, dispersion polymerisation and precipitation polymerisation in scC02. Particular attention has been given to the equipment requirements for these reactions and the potential for industrial implementation of these techniques. Abstract only. 10 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.704082 Item 324 Supercritical Fluid Technology. Conference proceedings. Birmingham, 15th-17th Sept.1997, paper 5. 91141T PARTICLE FORMATION BY SUPERCRITICAL

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FLUID TECHNOLOGIES York P Bradford,University (Royal Society of Chemistry,Process Technology Group; SCI Separation Science & Technology Group; SCI Process Engineering Group; Environmental Technology Best Practice Programme) While the Àrst observations of the use of supercritical Áuids (SCF) to precipitate particles were made over a century ago, it is only relatively recently that researchers have adapted these approaches to address the limitations of currently used particle formation and processing operations. Throughout the particle formation and powder handling industries, conventional solvent crystallisation and precipitation methods are widespread, although difÀculties frequently arise. These range from problems with Àltering and harvesting Àne particles, environmental issues when milling to obtain desired particle size, to quality and regulatory concerns, such as product being out of speciÀcation for levels of retained solvent, and batch to batch variation which can cause downstream inefÀciency and even product malfunction. An alternative procedure with direct formation of particles of specified and controlled physicochemical criteria, such as size and shape, and enhanced handling properties is needed by industry. This is especially so for the pharmaceutical industry where the bioperformance of drug substances is often determined, inter alia, by particle properties. A recent development has been to cointroduce into a particle formation vessel the solution of material of interest and an SCF via a coaxial nozzle whereby the SCF acts simultaneously as an antisolvent and also as a mechanical dispersing agent to rapidly produce dry particles. This process, called SEDS (solution enhanced dispersion by supercritical Áuids), has been shown to produce solvent free Àne particles for a range of materials including pharmaceuticals, proteins and polymers. Extended abstract only. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.704081 Item 325 Supercritical Fluid Technology. Conference proceedings. Birmingham, 15th-17th Sept.1997, paper 3. 91141T CHEMISTRY IN SUPERCRITICAL FLUIDS Poliakoff M; Howdel S M Nottingham,University (Royal Society of Chemistry,Process Technology Group; SCI Separation Science & Technology Group; SCI Process Engineering Group; Environmental Technology Best Practice Programme) Supercritical fluids are highly compressed gases characterised by a curious combination of gas- and liquid-like properties which have fascinated scientists for generations. Currently, the combined pressures of environmental legislation and commercial competition

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References and Abstracts

are forcing many chemical companies to re-evaluate the possibility of replacing existing chemical technology by supercritical fluids. These fluids, and particularly supercritical CO2, scCO2, are becoming increasingly attractive as solvents for environmentally more acceptable chemical processes. High-pressure reactions, however, are more capital intensive than conventional low pressure processes. Therefore, supercritical Áuids will only gain widespread acceptance in those areas where the Áuids give real chemical advantages as well as environmental beneÀts. A number of examples illustrate some of these advantages. The examples range from promising laboratory reactions to processes which have already been commercialised or will be soon. Extended abstract only. 8 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.704080 Item 326 Supercritical Fluid Technology. Conference proceedings. Birmingham, 15th-17th Sept.1997, paper 2. 91141T PREPARATIVE CHROMATOGRAPHY: LIQUID OR SUPERCRITICAL ELUENTS Nicoud R-M NOVASEP (Royal Society of Chemistry,Process Technology Group; SCI Separation Science & Technology Group; SCI Process Engineering Group; Environmental Technology Best Practice Programme) Chromatography processes are being developed as production techniques with gas and mainly liquid eluents. These techniques are more and more used in the pharmaceutical industry, because of their Áexibility and their ability to solve difÀcult problems at reasonable costs. First industrial chromatographic processes using supercritical Áuids are announced. In order to transform a concept (the use of supercritical Áuids) into a technique, different technological aspects have to be carefully addressed: the column, the devices performing the solute/ eluent separation, the eluent loop, the co-solvent module. Whatever the physical state of the eluent, modelling is a key tool allowing the rapid development and optimisation of chromatographic processes. Good prediction models allow optimisation of classical elution systems, but also the design of new processes for which intuition is of limited help simulated moving bed or extrography. The chemical engineering tools allowing modelling of PSFC are similar to those allowing to model LC: mass balances, knowledge of adsorption isotherms, mass transfer coefÀcients. The main differences are due to the dependence of the Áuid viscosity and of the adsorption isotherms with respect to the pressure and thus to the position in the column. These properties make supercritical Áuids ‘adjustable’ solvents and most processes are based on these solvent power variations. A new and innovative process based on the association of columns to allow a continuous

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chromatography process and to take advantage of the variation of the solvent properties of supercritical Áuids is proposed. Extended abstract only. EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; WESTERN EUROPE

Accession no.704079 Item 327 Supercritical Fluid Technology. Conference proceedings. Birmingham, 15th-17th Sept.1997, paper 1. 91141T POLYMER FRACTIONATION Clifford A A Express Separations Ltd. (Royal Society of Chemistry,Process Technology Group; SCI Separation Science & Technology Group; SCI Process Engineering Group; Environmental Technology Best Practice Programme) Fractionation of polymers using supercritical Áuids is well established. In fact fractionation in supercritical Áuids has been a feature of polymer production from the 1940s and subsequent fractionation using a compressed gas was patented then. Time is a factor in these extractions which has previously been neglected. Modelling involves time and this leads to the idea of using a density gradient during extraction. An example of the use of a density gradient for the production of narrow fractions of polymers, i.e. those with low polydispersity, is given. However, by choosing an appropriate density programme, any distribution of molar mass in a polymer can, in principle, be produced. Narrow fractions of polymers are used as analytical standards for calibration in size-exclusion or gel permeation chromatography. A wide range of polymer samples are produced, typically with polydispersities of 1.05, for this purpose. For example, polymers can be fractionated by extracting them with a liquid using a solvent gradient: initial extraction being a ‘poor’ solvent, which extracts the lowest molar masses, to which a ‘better’ solvent is added in higher and higher proportions to extract fractions of progressively higher molar mass. For some polymers of lower molar mass, this and other methods are not successful because of their high solubility and the polymer fractions are made by preparing directly polymers of low polydispersity. However, the fractions made in this way have higher polydispersity than is desirable and at the same time these samples are more expensive. A possible solution is to extend the solubility range downwards by using supercritical Áuid extraction. Extended abstract only. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.704078 Item 328 Macromolecules 31, No.19, 22nd Sept.1998, p.6481-5 PULSED-LASER POLYMERISATION OF METHYL METHACRYLATE IN LIQUID AND

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References and Abstracts

SUPERCRITICAL CARBON DIOXIDE Quadir M A; DeSimone J M; van Herk A M; German A L North Carolina,University; Eindhoven,University of Technology The free-radical propagation rate coefÀcients for methyl methacrylate in liquid and supercritical carbon dioxide were determined using pulsed-laser polymerisation. The effect of carbon dioxide solvency on the propagation rate coefÀcient was examined. Results are compared with the bulk activation parameters for the propagation rate coefÀcient of methyl methacrylate as set by IUPAC. 33 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; NETHERLANDS; USA; WESTERN EUROPE

Accession no.699447 Item 329 Chemical Engineering 105, No.11, Oct.1998, p.32/41 German; English SUPERCRITICAL FLUIDS STAY SOLVENT Chin K; Crabb C; Ondrey G; Kamiya T The use of supercritical Áuids as environmentally-friendly alternatives to chlorinated solvents is discussed. These Áuids have already been used in coffee decaffeination and spice-extraction processes, but have yet to capitalise on the demand for environmentally-friendly alternatives in other segments of the chemical processes industries. Supercritical carbon dioxide applications for polymer processing are described. These include modiÀcation of aqueous processes to accommodate supercritical carbon dioxide, which eliminates the energy-intensive drying that is required when water is used, emulsion polymerisation using supercritical carbon dioxide, and use of supercritical carbon dioxide instead of water to dye polymer Àbres. USA

Accession no.699045

Item 331 Macromolecules 31, No. 16, 11th Aug. 1998, p.5407-14 THERMOPLASTIC VULCANISATES FROM ISOTACTIC POLYPROPYLENE AND ETHYLENE-PROPYLENE-DIENE TERPOLYMER IN SUPERCRITICAL PROPANE. SYNTHESIS AND MORPHOLOGY Han S J; Lohse D J; Radosz M; Sperling L H Exxon Research & Engineering Co.; Louisiana,State University; Lehigh University New thermoplastic vulcanisates were synthesised from isotactic PP and EPDM in a supercritical propane solution. The ternary solution of PP and EPDM in supercritical propane exhibited less solubility than the corresponding binary solutions of PP or EPDM separately in propane. Higher pressure is the supercritical polymer solution enhanced the mutual solubility of the two polymers. EPDM was crosslinked with tert-butyl peroxide while in supercritical solution. On lowering the pressure while remaining above the melting temperature of the polymers, the supercritical thermoplastic vulcanisate gel phase separated in a manner consistent with spinodal decomposition. On isobaric cooling of the supercritical thermoplastic vulcanisate gel, the PP crystallised, freezing the morphology. The crosslinking of EPDM in the homogeneous supercritical propane solutions was found to be nearly complete. The Ànal thermoplastic vulcanisates were phase separated, exhibiting two melting transitions. The morphology of the thermoplastic vulcanisates was a microporous, apparently closed cell polymeric foam. Phase contrast optical microscopy showed micro-heterogeneous EPDM domains dispersed in the PP matrix for the thermoplastic vulcanisates. The phase domain sizes were much smaller, by a factor of 5 to 10, than those of the corresponding melt blends. Phase diagrams are shown for solutions and both optical and SEM micrographs for solids. 25 refs. USA

Item 330 Patent Number: US 5739223 A 19980414 METHOD OF MAKING FLUOROPOLYMERS DeSimone J M North Carolina,Chapel Hill University A process for making a Áuoropolymer is disclosed. The process comprises solubilising a Áuoromonomer in solvent comprising a carbon dioxide Áuid, and then polymerising the fluoromonomer to produce the fluoropolymer. A preferred solvent for carrying out the process is supercritical carbon dioxide; preferred Áuoromonomer for carrying out the process are Áuoroacrylate monomers such as 1,1-dihydroperÁuorooctyl acrylate. The polymerisation step is preferably carried out in the presence of an initiator such as azobisisobutyronitrile. USA

Accession no.697872

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Accession no.696669 Item 332 Patent Number: EP 854165 A1 19980722 METHOD OF AND APPARATUS FOR DECOMPOSING WASTE Nagase Y; Fukuzato R Kobe Steel Ltd. Chemical plant waste, which contains target compounds having one or more hydrolysable bonds, e.g. ether, ester, amide or isocyanate bonds, is continuously supplied in a molten state or liquid state to a reactor, supercritical water or high pressure/high temperature water is continuously supplied to the reactor, the water is brought into contact with the waste to decompose the target compounds and the decomposed target compounds are recovered as raw material compounds or derivatives thereof for the target compounds. The target compounds were previously

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incinerated or discarded. JAPAN

Accession no.694962 Item 333 Polymer Engineering and Science 38, No.7, July 1998, p.1112-20 EXTRUSION OF PE/PS BLENDS WITH SUPERCRITICAL CARBON DIOXIDE Minhee Lee; Tzoganakis C; Park C B Waterloo,University; Toronto,University The effects of dissolved supercritical carbon dioxide on the viscosity and morphological properties were investigated for PE/PS blends in a twin-screw extruder. The viscosities of the blend/carbon dioxide solutions were measured at various carbon dioxide concentrations using a wedge die mounted on the extruder. The effect of processing parameters on the size of the dispersed PS phase and cell structure were investigated at various extrusion conditions and carbon dioxide concentrations. 47 refs. CANADA

Accession no.694905 Item 334 Japan Chemical Week 39, No.1990, 3rd Sept.1998, p.2 EPDM CAN BE RECYCLED WITH SUPERCRITICAL WATER It is brieÁy reported that Nishikawa Rubber has Ànished a basic study on chemical recycling technology for vulcanised EPDM. The technology enables the cracking of used EPDM into a compound with a molecular weight of 1,000-5,000 in supercritical water with sodium hydroxide under a high temperature and pressure. NISHIKAWA RUBBER CO. JAPAN

Accession no.691538 Item 335 Industrial and Engineering Chemistry Research 37, No.8, Aug.1998, p.3067-79 SOLUBILITY OF HOMOPOLYMERS AND COPOLYMERS IN CARBON DIOXIDE O’Neill M L; Cao Q; Fang M; Johnston K P; Wilkinson S P; Smith C D; Kerschner J L; Jureller S H Texas,University; Air Products & Chemicals Inc.; Unilever Research The cloud points of various amorphous polyether, polyacrylate and polysiloxane homopolymers and some commercially-available block copolymers were measured in carbon dioxide at temps. from 25 to 65C and pressures of about 1000 to 6000 psia. The solubility parameters of the amorphous polymers, almost without exception, increased with a decrease in the cohesive energy density

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(or the surface tension of the polymer). With this decrease in surface tension, the polymer cohesive energy density became closer to that of carbon dioxide. Solubility was thus governed primarily by polymer-polymer interactions, while polymer-carbon dioxide interactions played a secondary role. The solubility was strongly dependent on molec.wt. for the less carbon dioxide-philic polymers. The solubilities of high molec.wt. polyÁuoroalkoxyphosp hazenes in carbon dioxide were comparable with those of poly(1,1-dihydroperÁuorooctylacrylate). 56 refs. USA

Accession no.691497 Item 336 Revista de Plasticos Modernos 73, No.488, Feb.1997, p.141-8 Spanish LATEST TECHNOLOGICAL DEVELOPMENTS IN THE PRODUCTION OF POLYETHYLENE Vargas L Repsol SA Developments in metallocene catalysts and suspension and gas phase polymerisation processes for PE production are reviewed, and the advantages of bimodal PE resins are examined. Statistics show world production capacities for PE in 1995 with forecasts for 2000, and West European PE consumption by application in 1993. 29 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; SPAIN; WESTERN EUROPE; WESTERN EUROPE-GENERAL; WORLD

Accession no.691292 Item 337 Journal of Applied Polymer Science 69, No.5, 1st Aug.1998, p.911-9 SUPERCRITICAL FLUID DYEING OF PMMA FILMS WITH AZO-DYES West B L; Kazarian S G; Vincent M F; Brantley N H; Eckert C A Georgia,Institute of Technology In-situ UV-vis spectroscopy was used to study diffusion of two azo dyes in a carbon dioxide-swollen matrix of PMMA. The diffusivity of both dyes can be tuned simply by changing the system pressure. The partitioning of the dyes between the polymer phase and the Áuid phase was measured. 40 refs. USA

Accession no.689709 Item 338 Macromolecules 31, No.14, 14th July 1998, p.4614-20 PREPARATION AND CHARACTERISATION OF MICROCELLULAR POLYSTYRENE FOAMS PROCESSED IN SUPERCRITICAL CARBON DIOXIDE

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References and Abstracts

Arora K A; Lesser A J; McCarthy T J Massachusetts,University Rapid decompression of supercritical carbon dioxidesaturated PS at sufÀciently high temperatures (above the depressed Tg) yields expanded microcellular foams. The resulting foam structures can be controlled by manipulating processing conditions. Experiments varying the foaming temperature while holding other variables constant show that higher temperatures produce larger cells and reduce densities. Structures range from isotropic cells in samples retaining their initial geometry to highly expanded foams recovered in the shape of the foaming vessel and having oriented anisotropic cells and limited density reduction. Higher saturation pressures lead to higher nucleation densities and hence smaller cells. Decreasing the rate of depressurisation permits a longer period of cell growth and therefore larger cell sizes. Foams having a bimodal distribution of cell sizes can be created by reducing the pressure in two stages. Relevance to the production of foamed blends is suggested. SEM micrographs show the size and shape of cells. 18 refs. USA

Accession no.689680 Item 339 Antec ‘98. Volume II. Conference proceedings. Atlanta, Ga., 26th-30th April 1998, p.1407-10. 012 VISCOSITY REDUCTION OF POLYMERS BY THE ADDITION OF SUPERCRITICAL CARBON DIOXIDE IN POLYMER PROCESSING Elkovitch M D; Lee L J; Tomasko D L Ohio,State University (SPE) The viscosity of a polymer often dictates the manner in which a polymer is processed, as well as the end use capabilities, mechanical strength and cost. As the viscosity of polymers is increased so is the energy required to process them. Plasticising agents are often added to high viscosity materials to aid in processing. Supercritical carbon dioxide, scCO2, can be added to polymer melts to lower their viscosity. ScO2 is injected into the barrel of a Haake single-screw extruder with a 0.75 inch screw and L/D = 25 that is processing PS. This technique results in a substantial drop in polymer melt viscosity as is measured by a slit die rheometer attached to the single-screw extruder. 9 refs. USA

Accession no.688621 Item 340 Antec ‘98. Volume II. Conference proceedings. Atlanta, Ga., 26th-30th April 1998, p.1418-20. 012 SUPERCRITICAL FLUIDS AS POLYMER PROCESSING AIDS Khan V; Kwag C; Manke C W; Gulari E Wayne State,University (SPE)

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The behaviour of molten thermoplastic polymers containing dissolved supercritical gases are pertinent to such processing operations as the manufacture of thermoplastic composites and polymer foams. Knowledge of supercritical gas solubility in polymer melts and the effects of these dissolved gases and supercritical Áuids on the physical properties of the melts are important for these processes. Measured viscosity ratios of PS melts with dissolved carbon dioxide and 1,1-diÁuoroethane relative to the viscosity of pure PS at temperatures above the glass transition temperature of PS are reported. A modiÀed freevolume theory is combined with thermodynamic models to predict the measured viscosity ratios. 4 refs. USA

Accession no.687566 Item 341 Antec ‘98. Volume II. Conference proceedings. Atlanta, Ga., 26th-30th April 1998, p.1415-7. 012 IN SITU SPECTROSCOPY OF CO2-INDUCED PLASTICISATION OF GLASSY POLYMERS Kazarian S G; Brantley N H; Eckert C A Georgia,Institute of Technology (SPE) In situ spectroscopy is used to study the plasticisation of glassy polymers by high-pressure and supercritical CO2. The methodology for in situ spectroscopic analysis of the interactions between CO2 and polymers is described. The changes in IR spectra of CO2 incorporated into various polymers indicate a speciÀc interaction between CO2 and polymer functional groups. Increased polymer segmental mobility is also observed, indicative of the plasticisation phenomenon. Implications of these discovered molecular interactions are discussed. 25 refs. USA

Accession no.687565 Item 342 Antec ‘98. Volume II. Conference proceedings. Atlanta, Ga., 26th-30th April 1998, p.2538-41. 012 SUPERCRITICAL FLUID ASSISTED POLYMER BLENDING Elkovitch M D; Lee L J; Tomasko D L Ohio,State University (SPE) The melt viscosity of individual homopolymers is one of the most important parameters inÁuencing polymer blending. Often blending involves components with vastly different viscosities. Supercritical carbon dioxide can be added to polymer melts in order to lower their viscosities, such that effective polymer blending will occur. A blend system of a high viscosity PMMA and low viscosity PS (viscosity ratio ca 20) is analysed. Carbon dioxide has a higher afÀnity for PMMA than for PS. Therefore the viscosity of the PMMA is selectively lowered by the carbon dioxide such that it becomes closer

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to that of PS. An improvement in polymer blending results. 10 refs. USA

Accession no.687407 Item 343 European Chemical News 69, No.1815, 1st-7th June 1998, p.25 TAKEDA/KOBE RECYCLING UNIT RECOVERS TDA It is brieÁy reported that Takeda Chemical Industries has started up a recycling unit using supercritical water technology to recover toluene diamine during manufacture of toluene diisocyanate at its Kashima plant in Japan. The technology has been jointly developed by Takeda and Kobe Steel. The recycling unit has a TDA recovery rate of 80%. TAKEDA CHEMICAL INDUSTRIES LTD.; KOBE STEEL LTD. JAPAN

Accession no.680580 Item 344 Polymers Paint Colour Journal 188, No.4400, Jan.1998, p.14-7 SUPERCRITICAL FLUID TECHNOLOGIES - NEW OPPORTUNITIES FOR COATING AND IMPREGNATING PLASTICS AND ELASTOMERS Hay J N; Johns K Surrey,University; Chemical & Polymer It is explained that, usually, large quantities of undesirable solvents are released during the application of coatings. This article looks at a new development which involves replacing the solvent (in part or completely) by carbon dioxide under supercritical conditions. Full details of the work are provided. 30 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.677252 Item 345 Journal of Polymer Science : Polymer Physics Edition 36, No.4, March 1998, p.617-27 ISOTACTIC POLYPROPYLENE FOAMS CRYSTALLIZED FROM COMPRESSED PROPANE SOLUTIONS Whaley P D; Kulkarni S; Ehrlich P; Stein R S; Winter H H; Conner W C; Beaucage G Massachusetts,University; Cincinnati,University Crystallisation of isotactic PP from homogeneous solution in supercritical propane yielded open-cell foams of high surface area. Their morphology usually consisted of microspheres with a dense core and a porous periphery of radiating Àbrils. Pore radii covering the mesopore range (2-

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50nm), making their largest contribution at 10-20 nm, were calculated from nitrogen adsorption isotherms. Surface areas of the correct order of magnitude were obtained by assuming that gas adsorption took place on the surfaces of lamellar crystals. Crystallisation of isotactic PP from n-butane and n-heptane generated foams of lower mesoporosity and smaller surface area. These more ‘liquid-like’ solvents did not allow for formation of an open network of mesopores or they promoted its collapse upon their removal. 22 refs. USA

Accession no.672015 Item 346 Fibres and Textiles in Eastern Europe 5, No.3, 1997, p.70-3 WATER-FREE DYEING OF HIGHPERFORMANCE FIBROUS MATERIAL WITH SUPERCRITICAL CARBON DIOXIDE AS DYEING BATH (SFD) Knittel D; Schollmeyer E Deutsches Textilforschungszentrum Nord-West eV The results of water-free dyeing of high-performance Àbres (aramids, polyarylketones, polyarylsulphides) are described. The new dyeing process is based on the use of supercritical carbon dioxide as a dyeing medium and on the use of disperse dyestuffs. Selective laboratory screening experiments are presented. Dyestuff uptake depends on structure of the polymers and has to be optimised. High washing fastnesses are obtainable. 17 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.668597 Item 347 Plastics Engineering 53, No.12, Dec.1997, p.37-40 CARBON DIOXIDE AS A CONTINUOUS PHASE FOR POLYMER SYNTHESIS Canelas D A; Burke A L C; DeSimone J M North Carolina,University The use is investigated of supercritical carbon dioxide in polymer synthesis with reference to the advantages it affords beyond the simple elimination of the use of organic solvents or water. Advantages in the properties and processing of materials are examined, which can be realised through the use of this medium, which are reported to be principally as a result of the lack of chain transfer and high plasticisation propensity. 82 refs. USA

Accession no.667077 Item 348 Patent Number: EP 818292 A2 19980114 PROCESS FOR PREPARING EXPANDED PRODUCT OF THERMOPLASTIC RESIN

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References and Abstracts

Nishikawa S; Yorita K; Ichikawa K; Inoue H; Eriguchi M; Sueda T; Amemiya H Mitsui Toatsu Chemicals Inc. Supercritical carbon dioxide and/or nitrogen is added, as a blowing agent, to a thermoplastic resin and melted therein. The resulting molten resin composition is cooled under a pressure not less than a critical pressure of the blowing agent and discharged from a die to lower the pressure to a level not more than the critical pressure and the expanded product is cooled to a level not more than the Tg or crystallisation temperature of the resin to control the cell diameter of the expanded product. The process uses a shear rate adjusting section, which generates a shear rate in a speciÀed range and has a sectional area (A), and a Áow velocity distribution adjusting section, which lowers the shear rate and has a sectional area (B), B/A being in the range of 1.3 to 20. The foams obtained have excellent surface appearance, high strength and cells of a Àne average cell diameter and a uniform average cell density. JAPAN

Accession no.664244

Polypyrrole was synthesised via thermal decarboxylation of a precursor monomer, pyrrole-2-carboxylic acid, using ferric salts in both supercritical carbon dioxide and supercritical Áuoroform. Pressed pellet conductivities were determined, and SEM revealed an unusual non-spherical morphology. 10 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.657616 Item 351 Patent Number: EP 798314 A1 19971001 DEVOLATILISATION Krupinski S; McQueen J T Nova Chemicals (International) SA A polymer melt may be devolatilised to less than 500, preferably less than 150 ppm, of residual volatile material by injecting into the melt an amount of a supercritical Áuid greater than the amount of residual volatile material in the melt, typically not more than about 10 wt.%, and passing the melt through a Áash chamber devolatiliser at a speciÀed pressure and a temp. of from 200 to 350C. SWITZERLAND; WESTERN EUROPE

Item 349 Journal of the National Institute of Materials and Chemical Research 5, No.4, 1997, p.175-183 Japanese APPLICATION OF SUPERCRITICAL FLUIDS TO EARTH ENVIRONMENT PROTECTION TECHNOLOGY Sako T; Sugeta T Three kinds of promising innovative environmental applications using supercritical Áuids to solve problems of energy, resources and global environment are shown: the complete decomposition of hazardous compounds with supercritical water, the recycling of waste plastics with supercritical methanol or supercritical water, and chemical reaction in supercritical carbon dioxide which is free from toxic organic solvents. Supercritical methanol depolymerised waste condensation polymers such as PETP and PEN into constituent monomers easily. The supercritical water decomposed composite plastics such as FRP into the glass Àbre and fuel oil with high efÀciency. 12 refs. JAPAN

Accession no.662847 Item 350 Journal of Materials Chemistry 7, No.10, Oct.1997, p.1965-6 FIRST EXAMPLE OF A CONDUCTING POLYMER SYNTHESISED IN SUPERCRITICAL FLUIDS Kerton F M; Lawless G A; Armes S P Sussex,University

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Accession no.656382 Item 352 Macromolecules 30, No.4, 24th Feb.1997, p.745-56 DISPERSION POLYMERISATION OF METHYL METHACRYLATE IN SUPERCRITICAL CARBON DIOXIDE Lepilleur C; Beckman E J Pittsburgh,University A series of graft copolymers, poly(methyl methacrylateco-hydroxyethyl methacrylate)-g-poly(perÁuoropropylene oxide), was synthesised for application as stabilisers in dispersion polymerisation of methyl methacrylate in supercritical carbon dioxide. The backbone, poly(methyl methacrylate-co-hydroxyethyl methacrylate), is effectively insoluble in carbon dioxide and the grafted chains, poly(perÁuoropropylene oxide), are completely miscible in carbon dioxide at moderate pressures. The effect of molecular architecture on polymerisation rate and PMMA particle size was evaluated by varying the molecular weight of the anchor group (backbone of the copolymer), molecular weight of the carbon dioxide-soluble graft chain, and graft chain density. The efÀciency of the graft copolymers as dispersants was demonstrated as micronsize polymer beads of molecular weight greater than 100000 were produced. The results showed that a careful balance between anchor group size (backbone length) and amount of soluble component (either graft chain length or graft chain density) is necessary, but not sufÀcient to achieve adequate stabilisation and that the distribution of the soluble component along the anchor group was also important. Furthermore, the backbone molecular

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weight was shown as the key component for stabilisation, provided that enough carbon dioxide-philic component has been included to ensure solubility. 38 refs. USA

Accession no.651555 Item 353 Advances in Polymer Science No.133, 1997, p.103-40 POLYMERIZATIONS IN LIQUID AND SUPERCRITICAL CARBON DIOXIDE Canelas D A; DeSimone J M North Carolina,University A review is presented of the literature on the use of carbon dioxide as an inert solvent for the synthesis and processing of polymers. Homogeneous solution polymerisations are discussed with emphasis on free radical chain growth and cationic chain growth in the synthesis of Áuoropolymers. Heterogeneous polymerisations are then considered, with reference to free radical precipitation polymerisations, dispersion and emulsion polymerisations, heterogeneous cationic polymerisations, metal-catalysed polymerisations, step growth polymerisations and hybrid systems. 148 refs. USA

Accession no.651346 Item 354 Journal of Polymer Science : Polymer Chemistry Edition 35, No.10, 30th July 1997, p.2009-13 DISPERSION POLYMERIZATION OF METHYL METHACRYLATE IN SUPERCRITICAL CARBON DIOXIDE: INFLUENCE OF HELIUM CONCENTRATION ON PARTICLE SIZE AND PARTICLE SIZE DISTRIBUTION Yu-Ling Hsiao; Desimone J M North Carolina,University Dispersion polymerisations of MMA using poly(1,1dihydroperfluorooctyl acrylate) as a steric stabiliser in supercritical carbon dioxide were carried out in the presence of helium. Particle size and particle size distribution were found to be dependent on the amount of inert helium present. Particle sizes ranging from 1.64 to 2.66 micrometres were obtained with various amounts of helium. Solvatochromic investigations using 9(alpha-perÁuoroheptyl-beta,beta-dicyanovinyl)julolidine indicated that the solvent strength of carbon dioxide decreased with increasing helium concentration. This effect was confirmed by calculations of Hildebrand solubility parameters. Dispersion polymerisation results indicated that PMMA particle size could be attenuated by the amount of helium present in supercritical carbon dioxide. 34 refs. USA

Accession no.648202

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Item 355 Informations Chimie No.375, Feb.1996, p.83-94 French REVOLUTION OF METALLOCENES AND NEW POLYMERISATION PROCESSES Gauthier X V Developments in metallocene polymerisation catalysts for polyoleÀn synthesis are examined, and commercial developments by a number of companies are reviewed. Some new polymerisation processes, including supercritical suspension, high temperature and supercondensing mode gas phase polymerisation, are also described. 6 refs. WORLD

Accession no.643008 Item 356 Macromolecules 30, No.9, 5th May 1997, p.2792-4 FORMATION OF CELLULOSE ACETATE FIBERS BY THE RAPID EXPANSION OF SUPERCRITICAL METHANOL SOLUTIONS Aniedobe N E; Thies M C Clemson,University The rapid expansion of secondary cellulose acetate from supercritical methanol solutions was investigated. Particular attention was paid to determining whether or not continuous Àbres could be made and the extent to which degradation of cellulose acetate occurred because of the elevated processing temps. 7 refs. USA

Accession no.638826 Item 357 Antec 97. Volume II. Conference proceedings. Toronto, 27th April-2nd May 1997, p.1991-5. 012 ON-LINE MEASUREMENT OF PS/CO2 SOLUTION VISCOSITIES Lee M; Park C B; Tzoganakis C Waterloo,University; Toronto,University (SPE) The reduction of viscosity via gas dissolution in a polymer is well explained in terms of the dilution and the free volume increase. The viscosity of polymer/supercritical Áuid (SCF) solutions has been studied by theoretical prediction or off-line measurement to date. A technology for the on-line measurement of melt viscosity of PS/SCF solutions is presented using a linear capillary tube die mounted on a single-screw extruder. Carbon dioxide is injected into the extrusion barrel and the content of CO2 is varied in the range of 0 to 4% by weight using a positive displacement pump. Single-phase polymer/SCF solutions are made using a microcellular extrusion system and formation of two-phase mixture is prevented by maintaining a high pressure in the capillary tube die. By

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References and Abstracts

measuring the pressure drops through the die, the viscosity of PS/CO2 solutions is determined. The solubility of CO2 is estimated by monitoring the pressure drops and the absolute pressure in the die. The effect of pressure on the viscosity of a PS/CO2 solution is also discussed. 27 refs. CANADA

Accession no.638327 Item 358 Patent Number: US 5559198 A 19960924 PROCESS FOR PREPARING POLYVINYL TRIFLUOROACETATE AND POLYVINYL TRIFLUOROACETATE/VINYL ESTER COPOLYMERS IN SUPERCRITICAL CO2 Eian G L; Elsbernd C L S Minnesota Mining & Mfg.Co. Polyvinyl triÁuoroacetate (PVTFA) is obtained in relatively high yield under mild conditions by using carbon dioxide under supercritical conditions, as a solvent. Synthesis of syndiotactic PVTFA on a commercial scale without the use of environmentally-harmful solvents is made possible by the process, which provides a convenient route to syndiotactic PVAL. USA

Accession no.635518 Item 359 Journal of Applied Polymer Science 64, No.7, 16th May 1997, p.1309-17 HIGHLY REFLECTIVE POLYIMIDE FILMS CREATED BY SUPERCRITICAL FLUID INFUSION OF A SILVER ADDITIVE Boggess R K; Taylor L T; Stoakley D M; St.Clair A K US,NASA,Langley Research Center; Radford,University Supercritical Áuid infusion of a silver-containing additive into a fully cured polyimide was achieved with moderately high-density carbon dioxide at 110C. The nature of the silver and its distribution within the Àlm and on the Àlm surface were established via microscopy and surface analysis techniques. 25 refs. USA

Accession no.635399 Item 360 Patent Number: US 5550211 A 19960827 METHOD FOR REMOVING RESIDUAL ADDITIVES FROM ELASTOMERIC ARTICLES DeCrosta M A; Jagnandan I Schering Corp. The articles are cleaned by contacting them with at least one supercritical Áuid under conditions and for a time sufÀcient to remove the phthalates and/or polynuclear aromatic hydrocarbons contained therein. Articles having reduced phthalate contents can be used as gaskets, valves, seats, Áaps

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or plugs in metered dose delivery devices, such as aerosols for demanding medicinal and pharmaceutical uses. USA

Accession no.633883 Item 361 Journal of Polymer Science : Polymer Physics Edition 35, No.3, Feb.1997, p.523-34 RHEOLOGY OF POLYDIMETHYLSILOXAN E(PDMS) SWOLLEN WITH SUPERCRITICAL CARBON DIOXIDE Gerhardt L J; Manke C W; Gulari E Wayne State,University Viscosity curves were measured for PDMS melts swollen with dissolved carbon dioxide at 50 and 80C for shear rates ranging from 40 to 2300/s, and for carbon dioxide contents ranging from 0 to 21 wt %. The measurements were performed with a capillary extrusion rheometer modiÀed for sealed, highpressure operation to prevent degassing of the melt during extrusion. The concentration-dependent viscosity curves for these systems were self-similar in shape, exhibiting low-shear rate Newtonian plateau regions followed by shear-thinning power-law regions. Considerable reduction of viscosity was observed as the carbon dioxide content increased. Classical viscoelastic scaling methods, employing a compositiondependent shift factor to scale both viscosity and shear rate, were used to reduce the viscosity data to a master curve at each temp. The dependence of the shift factors on polymer chain density and free volume were investigated by comparing the shift factors for PDMS-carbon dioxide systems with those obtained by iso-free volume dilutions of high molec. wt. PDMS. This comparison suggested that the free volume added to PDMS upon swelling with dissolved carbon dioxide was the predominant mechanism for viscosity reduction in those systems. 19 refs. USA

Accession no.625151 Item 362 Polymer Recycling 2, No.2, 1996, p.77-82 CHEMICALS OF COMMERCE FROM RECYCLED SCRAP TYRES Dhawan J C; Huddleston H T South Alabama,University Tyre disposal problems are highlighted. The application of supercritical Áuid (SCF) technology to produce liquid hydrocarbons is discussed. The SCF-liquid can be blended with crude oil for upgrading in an existing reÀnery scenario or it could be fractionated to produce a variety of low molecular weight aromatic hydrocarbons, The SCF-tyre oil process is safe to operate since the pressure energy at supercritical conditions is contained in the liquid. The process would only require ‘off the shelf’ processing equipment. 16 refs. USA

Accession no.622309

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Item 363 R’95 - Recovery, Recycling, Re-Integration. Volume IV: Chemical Processes, Biological Processes, Hospital Waste. Conference proceedings. Geneva, 1st-3rd Sept. 1995, p.IV.14-21. 8(13) DEGRADATION OF POLYMERS AND ADDITIVES IN SUB- AND SUPERCRITICAL WATER Hirth T; Bunte G; Eisenreich N; Krause H; Schweppe R Fraunhofer-Institut fuer Chemische Technologie Edited by: Barrage A; Edelmann X (EMPA; Swiss Federal Laboratories for Mat.Testing & Res.)

separate halogenated Áame retardants out of polymer composites seems to be the extraction by supercritical Áuids like C02. The main objective is to Ànd suitable conditions for high extraction efÀciencies. For model mixtures involving the Áame retardants TBBA, TBPA and HBCD, the extraction efÀciency from the inert matrix MgSO4 was examined in relation to extraction pressure, temperature and time. The data form the basis for realistic tests on ABS composites with different Áame retardants.

Polymers include problematic substances, e.g. Àre retardants, which, for ecological reasons, cannot be passed on to the environment but have to be disposed of by the correct disposal process. These substances are usually disposed of by incineration. However, as the waste materials contain halogen and nitrogen compounds, their disposal poses considerable problems. Thus, in the elimination of chlorinecontaining organic waste materials, the formation of hydrogen chloride, chlorine and dioxins must be reckoned with, whereas nitrous oxides may also be produced on the destruction of waste materials containing nitrogen. The removal of compounds containing chlorine is discussed, and new possible conversion processes are presented: pressure hydrolysis in subcritical and supercritical water and the supercritical water oxidation. These processes are used for the degradation of monomers, polymers and additives. When alkaline hydrolysis of halogenated polymers is carried out in the supercritical range, e.g. at 500 deg.C , over 98 % of the organically bonded chlorine in the aqueous phase is found. In this process the principal polymer chain is also decomposed. Under supercritical water conditions it is also possible to oxidise additives from plastics like Àre retardants. First results have shown that compounds like tetrabromophthalic acid anhydride break down in supercritical water to form carbon dioxide, water and bromide. 6 refs.

Item 365 Antec ‘96. Volume II. Conference proceedings. Indianapolis, 5th-10th May 1996, p.2326-30. 012 IMPACT OF SUPERCRITICAL FLUIDS ON THE MORPHOLOGY OF POLYETHERETHERKETONE Kander R G; Lee J R Virginia,Polytechnic Institute & State University (SPE)

EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.615222 Item 364 R’95 - Recovery, Recycling, Re-Integration. Volume IV: Chemical Processes, Biological Processes, Hospital Waste. Conference proceedings. Geneva, 1st-3rd Sept. 1995, p.IV.3-8. 8(13) EXTRACTION OF BROMINATED FLAME RETARDANTS FROM POLYMER COMPOSITES WITH SUPERCRITICAL CARBON DIOXIDE Bunte G; Hardle T; Mariothe E; Michelfelder B Fraunhofer-Institut fuer Chemische Technologie Edited by: Barrage A; Edelmann X (EMPA; Swiss Federal Laboratories for Mat.Testing & Res.) In the Àeld of polymer recycling and/or disposal of e.g. polymer composites of mass consumer products, new techniques are highly required. One promising way to

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EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.615221

The application of supercritical Áuid (SCF) technology to high-performance polymers is becoming increasingly important as such polymers become more prevalent in industry. The response of fabricated parts to SCF environments can be critical to performance. This study examines the effects of absorption of SCFs on the crystallisation behaviour of polyaryletheretherketone (PEEK). Special attention is given to the ability to induce different levels of crystallinity by exposing PEEK to chlorodiÁuoromethane at various supercritical conditions. 29 refs. USA

Accession no.606522 Item 366 Polymer 37, No.15, 1996, p.3405-10 EFFECT OF STRUCTURE ON GAS SOLUBILITY AND GAS INDUCED DILATION IN A SERIES OF POLY(URETHANE) ELASTOMERS Briscoe B J; Kelly C T London,Imperial College of Science,Technology & Medicine The interaction of high pressure subcritical and supercritical carbon dioxide with a series of PU elastomers of differing hard segment content was studied by means of dilation and dynamic mechanical studies in a high pressure cell. Pressures were up to 23 MPa. The data indicates that, for this particular series of ester-based polyurethanes, the extent of sorption and dilation are directly related to the structural properties of each polymer including the extent and characteristics of the soft phase component. DSC data are given for each PU. 18 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.606324

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References and Abstracts

Item 367 Patent Number: US 5462973 A 19951031 SEPARATION OF POLYETHYLENE TEREPHTHALATE AND POLYVINYL CHLORIDE USING SUPERCRITICAL CARBON DIOXIDE Serad G A; Thornburg T S Hoechst Celanese Corp. A method for separating co-mingled polymeric materials, in particular PETP and PVC is described. The process involves selectively dissolving a superÀcial Áuid into one of the materials at the appropriate temperature and pressure. Upon rapid reduction of the system pressure, the selected material foams providing a change in density. Under ambient conditions, the polymeric materials having a large density difference can be separated by means of aqueous separation and Áotation. The preferred supercritical Áuid for the process is carbon dioxide, and PVC is the material into which the supercritical Áuid is preferentially dissolved. USA

Accession no.594423 Item 368 Japan Chemical Week 37, No.1874, 9th May 1996, p.6 USED PET RESIN DECOMPOSED INTO CHEMICAL MATERIALS The process is brieÁy described in which researchers at the National Institute of Materials & Chemical Research have completely decomposed PETP using supercritical Áuid. The process mixes used pulverised PETP which is mixed with methanol in a ratio close to 1:10 by weight, and in which the resultant product is put for 30 minutes under the speciÀed condition of 80-90 atmospheres and a temperature of 300 degrees C. to produce dimethyl terephthalate and ethylene glycol. The development hopes to help with legislation in which producers of PETP bottles are required to recycle them. JAPAN,NATIONAL INSTITUTE OF MATERIALS & CHEMICAL RESEARCH JAPAN

Accession no.590180 Item 369 Chemical Engineering 103, No.4, April 1996, p.48 SUPERCRITICAL FLUIDS MOVE INTO PLASTICS PROCESSING Parkinson G Supercritical Áuids may soon be used to make plastics, according to recent research. The article brieÁy describes the environmental and cost advantages, together with possible disadvantages of using supercritical Áuids in the processing of plastics. Brief details of a process for producing PETP, which offers advantages over current

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commercial methods are given. AMERICAN CHEMICAL SOCIETY; NORTH CAROLINA,UNIVERSITY USA

Accession no.587423 Item 370 Journal of Microencapsulation 13, No.2, March-April 1996, p.131-9 PRODUCTION OF DRUG LOADED MICROPARTICLES BY THE USE OF SUPERCRITICAL GASES WITH THE AEROSOL SOLVENT EXTRACTION SYSTEM(ASES) PROCESS Bleich J; Mueller B W Kiel,Christian-Albrecht-University The ASES process using supercritical gas was used for encapsulation of model drugs such as hyoscine butylbromide, indomethacin, piroxicam and thymopentin. As a carrier, the polymer poly-L-lactide was used. The resulting microparticles were investigated with regard to particle formation, morphology, particle size, size distribution and drug loading. With decreasing polarity of the incorporated drug, an increasing extraction occurred which lowered the drug loading of the microparticles. The extraction capacity of the gas phase depended on temp. and pressure, which determined density and polarity of the gas, The results obtained showed that the production conditions had to be optimised for each drug/polymer combination. Totally non-polar drugs were completely extracted together with the organic solvent, but polar drugs and especially peptides and proteins were easy to incorporate with the ASES process. 24 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.586391 Item 371 Materials World 4, No.1, Jan.1996, p.6 GREEN SOLVENT FOR ACRYLIC PLASTICS Research scientists at the University of Surrey are investigating whether acrylic plastics can be made using totally clean supercritical carbon dioxide in place of toxic solvents. The article supplies brief details of the beneÀts of using supercritical carbon dioxide, which is cheaper, easily recycled and leaves no toxic residue. SURREY,UNIVERSITY; EPSRC EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.583032

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Item 372 Patent Number: WO 9518834 A1 19950713 SUPERCRITICAL FLUID EXTRACTION INVOLVING HYDROFLUOROALKANES Blackwell J A; Chen D T; Alband T D; Perman C A Minnesota Mining & Mfg.Co. A composition containing Àrst and second components is contacted with a supercritical Áuid comprising 1,1,1,2tetraÁuoroethane or 1,1,1,2,3,3,3-heptaÁuoropropane or a mixture thereof, in the supercritical state under conditions and for a time sufÀcient to remove the Àrst component from the composition. USA

Accession no.582627 Item 373 2nd Annual Recycling Conference: Putting Plastics Recycling Technology to Use. Retec proceedings. Akron, Oh., 2nd-3rd Nov.1995, p.9-16 8(13) INNOVATIVE APPROACH TO IMPROVE THE QUALITY OF RECYCLED PLASTIC Agrawal R; Lancaster T; Papinsick J Liquid Carbonic Inc. (SPE,Recycling Div.; SPE,Akron Section) A novel technique is presented for removal of impurities from plastic using supercritical carbon dioxide in a twin-screw extruder. A 34 mm counterrotating, intermeshing twin-screw extruder was used. The source of plastic used was from kerbside collections consisting of detergent, fabric softener and milk bottles. The impurities contained in these bottles were aromatic hydrocarbons and fragrance type compounds like d-limonene. Control experiments were run by doping virgin plastic with naphthalene and then processing with supercritical carbon dioxide. It is shown that this process can remove contaminants within the plastic to 95% or greater efÀciencies. USA

Accession no.579418 Item 374 Journal of Applied Polymer Science 59, No.4, 24th Jan.1996, p.707-17 INTERACTION OF SUPERCRITICAL CARBON DIOXIDE WITH POLYMERS. II. AMORPHOUS POLYMERS Shieh Y T; Su J H; Manivannan G; Lee P H C; Sawan S P; Spall W D Lowell,University; Los Alamos National Laboratory Eleven different polymers of amorphous type were subjected to supercritical carbon dioxide treatment under a wide range of pressures and temps. The effects of the treatment on appearance, weight change, and thermal and mechanical properties were followed systematically. In addition, the effects of treatment conditions and dimension of the samples of weight changes were also monitored. It was found that amorphous polymers could absorb carbon dioxide to a greater extent than crystalline polymers and, in turn, the phenomenon of plasticisation was

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also very high. In addition to morphology, the polarity of the polymer was also crucial in determining the solubility in carbon dioxide. Comparison was also made with the behaviour of crystalline polymers. 12 refs. (Pt.I, ibid, p.695-705) USA

Accession no.576754 Item 375 Journal of Applied Polymer Science 59, No.4, 24th Jan.1996, p.695-705 INTERACTION OF SUPERCRITICAL CARBON DIOXIDE WITH POLYMERS. I. CRYSTALLINE POLYMERS Shieh Y T; Su J H; Manivannan G; Lee P H C; Sawan S P; Spall W D Lowell,University; Los Alamos National Laboratory The interaction of supercritical carbon dioxide with nine different crystalline polymers (four types of substituted and unsubstituted PE), PP, nylon 66, PETP, polyoxymethylene and PVDF) was studied systematically over a wide range of pressures and temps. Critical factors such as changes in appearance and weight, temp., pressure and time of the supercritical Áuid treatment and dimension of samples were observed. The effect of supercritical carbon dioxide on the thermal properties of treated polymers was investigated through TGA analysis. Changes in the mechanical properties, such as yield strength, ultimate elongation and elastic modulus, of the crystalline polymers studied were also observed. The possible implications of the observed changes for certain applications are discussed. 23 refs. USA

Accession no.576753 Item 376 PolyoleÀns IX. Conference Proceedings. Houston, Tx., 25th Feb-1st March,1995, p.31-47. 42C1 THIRD-GENERATION POLYOLEFIN TECHNOLOGIES AND THEIR CAPABILITIES Sinclair K B SRI International (SPE,South Texas Section; SPE,Thermoplastic Materials & Foams Div.) Three developments in polyoleÀn technology are discussed, together with their advantages over current commercial polyoleÀn processes. The developments are supercritical slurry processes for PE and PP, high-temperature PP processes and supercondensing gas-phase processes. These developments in process operating techniques, combined with recent developments in catalysis, promise to provide great improvements in productivity and product range capability. 5 refs. NESTE OY; HOECHST; MITSUBISHI PETROCHEMICAL; NOVACOR; DOW; UNION CARBIDE; EXXON; BASF USA

Accession no.576276

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References and Abstracts

Item 377 Macromolecules 28, No.24, 20th Nov.1995, p.8429-31 SYNTHESIS OF TETRAFLUOROETHYLENEBASED, NONAQUEOUS FLUOROPOLYMERS IN SUPERCRITICAL CARBON DIOXIDE Romack T J; DeSimone J M; Treat T A North Carolina,University; du Pont de Nemours E.I.,& Co.Inc.

The synthesis and fractionation by supercritical Áuid chromatography of an isotactic and symmetrical PMMA are described. Characterisation was undertaken by proton NMR. Single crystals were grown from a solution and the crystal structure was determined by X-ray analysis. 26 refs.

Copolymers of tetraÁuoroethylene with perÁuoro(propyl vinyl ether), as well as copolymers of tetraÁuoroethylene with hexaÁuoropropylene, were synthesised in high yields employing bis(perfluoro-2-propoxypropionyl) peroxide as a free radical initiator in supercritical carbon dioxide. Yield, copolymer composition and melting point data are shown in addition to SEM micrographs of morphology. For tetraÁuoroethylene-perÁuoro(propyl vinyl ether) copolymers, molecular weights were high and FTIR indicated the successful elimination of deleterious end groups. 28 refs.

Item 380 Patent Number: US 5412027 A 19950502 PREPARATION OF HOMOGENEOUS POLYMERS USING SUPERCRITICAL FLUID SOLUTIONS Shine A D; Smith S D; Noda I Procter & Gamble Co.; Delaware,University

USA

Accession no.576006 Item 378 Polymer 36, No.25, 1995, p.4817-26 MISCIBILITY, DENSITY AND VISCOSITY OF POLYDIMETHYLSILOXANE(PDMS) IN SUPERCRITICAL CARBON DIOXIDE Xiong Y; Kiran E Maine,University Phase boundaries, densities and viscosities of solutions of PDMS in supercritical carbon dioxide were determined. It was shown that the densities and phase behaviour could be well described with the Sanchez-Lacombe model. It was shown that the molec.wt. and MWDs had a signiÀcant effect on the observed demixing pressures. Viscosities of these solutions showed the usual behaviour in that temp. dependence followed Arrhenius-type behaviour with Áow activation energies of about 8 kJ/mol. Pressure dependence was also exponential, with the apparent volume of activation being in the range 30 to 60 cc/mol. The effects of temp. and pressure were uniÀed with density and the viscosity data were best correlated with Doolittle-type free volume based relationships. 28 refs. USA

Accession no.572198 Item 379 Polymer Journal (Japan) 27, No.9, 1995, p.951-8 CONTROLLED SYNTHESIS OF ISOTACTIC AND SYMMETRICAL PMMA DIRECTED TOWARD UNIFORM POLYMERS WITH HIGH CRYSTALLINITY Ute K; Yamasaki Y; Naito M; Miyatake N; Hatada K Osaka,University

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JAPAN

Accession no.565762

Homogeneous polymer blends are prepared from otherwise thermodynamically immiscible polymers, especially block copolymers. Thus, polymers, such as PS/PMMA block copolymer or PS/poly(1,2-butadiene) block copolymer, are dissolved under pressure in supercritical Áuid solvents, such as chlorodiÁuoromethane and n-butane, respectively, and expanded through a Àne nozzle. As the SCF solvent evaporates, the polymer deposits as a homogeneous material. USA

Accession no.564962 Item 381 Emerging Technologies in Plastics Recycling. Symposium proceedings. Philadelphia, Pa., 3rd-5th June 1991, p.172-85. 8(13) SEPARATION OF THERMOPLASTICS BY DENSITY USING NEAR-CRITICAL AND SUPERCRITICAL CARBON DIOXIDE AND SULPHUR HEXAFLUORIDE Super M S; Enick R M; Beckman E J Pittsburgh,University Edited by: Andrews G D; Subramanian P M (ACS,Div.of Polymer Chemistry) ACS Symposium Series 513 Near-critical and supercritical fluids composed of carbon dioxide and/or sulphur hexaÁuoride are used to sort thermoplastic waste mixtures according to density. For example, PVC can be readily removed from waste PETP, and tinted or Àlled materials can be separated from their clear and unfilled counterparts. Carbon dioxide alone can be used to separate polyoleÀns, while pure sulphur hexaÁuoride can be used to separate the non-olefin thermoplastics. Sulphur hexafluoride-rich CO2/SF6 mixtures can be used to separate all of the thermoplastics. The brief exposure of the thermoplastics to the mild temperature, high-pressure environment does not chemically alter them. The densities of the supercritical or near-critical Áuid mixtures are accurately correlated to temperature, pressure and Áuid composition using a cubic

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References and Abstracts

equation of state. 15 refs. USA

Accession no.564824 Item 382 Adhesives Age 38, No.10, Sept.1995, p.34-6 UNGLUING BY SUPERCRITICAL FLUIDS Manivannan G; Sawan S P Massachusetts,University The ability to unglue assembled parts will take on more importance as recycling issues continue to gain more importance. The use of supercritical carbon dioxide could Ànd a niche among various existing dismantling technologies. Aspects covered include adhesives and supercritical Áuid treatment. 6 refs. USA

Accession no.562909 Item 383 Cellular Polymers II. Conference proceedings. Edinburgh, 23-25th March 1993, paper 5. 6124 GENERATION OF MICROCELLULAR POLYMERS USING SUPERCRITICAL CO2 Goel S K; Beckman E J Pittsburgh,University (Rapra Technology Ltd.) Supercritical CO2 is known to be a very good swelling agent and plasticiser for PMMA, a consequence of an interesting combination of liquid-like and gas-like properties exhibited by supercritical fluids. Making use of this behaviour, a constant temperature process of generating microcellular polymers which employs a sudden pressure drop to induce phase separation in a solution of supercritical CO2 and PMMA is studied. The method is different from commonly-used temperature quench methods in that it makes use of the glass transition depression due to the presence of diluent in the polymer rather than heating the polymer to above its normal glass transition temperature. 24 refs. USA

Accession no.562718 Item 384 Polymer 36, No.16, 1995, p.3173-82 SEMICRYSTALLINE MICROFIBRILS AND HOLLOW FIBRES BY PRECIPITATION WITH A COMPRESSED FLUID ANTISOLVENT Luna-Barcenas G; Kanakia S K; Sanchez I C; Johnston KP Austin,University of Texas Precipitation with a compressed-Áuid antisolvent was studied theoretically and experimentally. Solutions of PAN in DMF sprayed into supercritical Áuid carbon dioxide

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form hollow Àbres and highly oriented microÀbril. In the dilute region, microÀbrils are produced with diameters as low as 100 nm due to the dipole forces, in contrast with microspheres produced from solutions of PS in toluene. For PAN microÀbrils, orientation increases with shear, then goes through a maximum and eventually decreases at higher Áow rates due to an expanding jet. The concentration for the transition from microÀbrils to a single hollow Àbre is in agreement with the calculated transition concentration (C) from the dilute to semidilute region. In the semidilute region, the morphology changes from hollow Àbres to highly oriented Àbrils with an increase in Áow rate. The increase in turbulence enhances convective mass transport, leading to more uniform nucleation throughout the crosssection of the jet, favouring the highly oriented Àbrils. The enhanced transport of carbon dioxide into the jet lowers the solvent quality, raising the above transition concentration (C), which further favours Àbril formation. For both PANDMF and PS-toluene solutions, the transition from highly oriented microÀbrils to hollow Àbres occurs at about 3C (in a good solvent), suggesting some similarities in the mass-transfer pathways in each system. 27 refs. USA

Accession no.562479 Item 385 Polymer 36, No.16, 1995, p.3099-102 PLASTICISATION OF A POLYURETHANE BY CARBON DIOXIDE AT HIGH PNEUMATIC STRESSES Briscoe B J; Kelly C T London,Imperial College of Science,Technology & Medicine The interaction of high pressure, subcritical and supercritical carbon dioxide with a polyesterurethane elastomer (Diprane 54) was studied. A novel optical high pressure cell was employed to examine the gas-polymer interactions at a molecular level, using FTIR. Spectra indicated that the hydrogen bonding between the polymer chains was disrupted by the imbibed gas. The data were then used in conjuction with temperature-dependent spectral data and the modulus-temperature characteristics of the polymer, to estimate the change in modulus of the polymer as a function of gas pressure. The predicted modulus of the PU was seen to fall as the gas pressure was increased, indicating that the PU was plasticised by the carbon dioxide. The plasticisation effect became the less dominant process at pressures above 12 MPa. The procedure provides a relatively convenient method for quantifying plasticisation in PU systems in the presence of high pneumatic stresses. Such data are valuable in predicting the consequences of gas-induced rupture during ambient gas decompression. 13 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; UK; WESTERN EUROPE

Accession no.562469

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References and Abstracts

Item 386 Advanced Materials Newsletter 17, No.16, 28th Aug.1995, p.6 SUPERCRITICAL FLUIDS CAN BENEFIT POLYMER AND COMPOSITE PROCESSES It is reported that researchers at the Center for Composite Materials have been introducing high pressure CO2 to act as a solvent, non-solvent or as a plasticiser. How the supercritical Áuids function depends on the Áuid density and which polymer or composite is being processed. The processing techniques could eventually prove useful in composite work; brief details are noted. US,CENTER FOR COMPOSITE MATERIALS USA

Accession no.561374 Item 387 Macromolecules 28, No.8, 10th April 1995, p.3002-4 CATIONIC POLYMERISATION OF VINYL AND CYCLIC ETHERS IN SUPERCRITICAL AND LIQUID CARBON DIOXIDE Clark M R; DeSimone J M North Carolina,University Vinyl ethers, particularly isobutyl vinyl ether, and oxetanes, particularly bis(ethoxymethyl)oxetane, were successfully polymerised cationically in carbon dioxide. Yield, molecular weight and MWD data are given. The processes became heterogeneous using hydrocarbon vinyl ethers and oxetanes, but high molar mass and high conversions could still be achieved. Homogeneous cationic polymerisations were also possible with several Áuorocarbon-based alkyl vinyl ethers and 3-methyl-3’((1,1-dihydroheptaÁuorobutoxy)methyl)oxetane. Control polymerisations were performed using cyclohexane and Freon-113 as solvent. 18 refs. USA

Accession no.550488

of polymer structure and morphology on the amount of non-ideality of the mixing behaviour as quantiÀed by the magnitude of the interaction parameter of the equation of state. Atomistic simulations were applied to the sorption and diffusion of carbon dioxide in bisphenol A polycarbonate. The heat of solution and diffusion coefÀcient could be calculated with rough but reasonable agreement with experimental results by using model systems of sufÀcient size and averaging over many such systems. 17 refs. USA

Accession no.549411 Item 389 Macromolecules 28, No.5, 27th Feb.1995, p.1724-6 FREE-RADICAL TELOMERISATION OF TETRAFLUOROETHYLENE IN SUPERCRITICAL CARBON DIOXIDE Romack T J; Combes J R; DeSimone J M North Carolina,University; Kenan Laboratories Telomerisation of tetrafluoroethylene was performed in supercritical carbon dioxide using AIBN as initiator and perÁuorobutyl iodide as telogen. Thermally initiated telomerisations were also performed. Safety advantages of using carbon dioxide are emphasised. Data are shown for yield, molecular weight (570-650) and polydispersity index. 15 refs. USA

Accession no.547164 Item 390 Macromolecules 28, No.4, 13th Feb.1995, p.912-5 PRECIPITATION POLYMERISATION OF ACRYLIC ACID IN SUPERCRITICAL CARBON DIOXIDE Romack T J; Maury E E; DeSimone J M North Carolina,University

Item 388 Antec ‘94. Conference Proceedings. San Francisco, Ca., 1st-5th May 1994, Vol.II, p.2105-9. 012 MODELLING OF THE TRANSPORT OF CARBON DIOXIDE THROUGH POLYMERS Bicerano J; Ralston A R K; Moll D J Dow Chemical Co.; Wisconsin-Madison,University (SPE)

Precipitation polymerisation was successful at pressures from 125 to 345 bar using AIBN as initiator. Analyses by GPC and SEM indicate that for the pressure range studied there was no appreciable effect on molecular weight, MWD, particle size or morphology. In addition, effective molecular weight control was demonstrated for precipitation polymerisation of acrylic acid in carbon dioxide through use of ethyl mercaptan as a chain transfer agent. 15 refs.

The sorption of carbon dioxide in a wide variety of polymers was modelled by the combination of a statistical thermodynamic equation of state with simple empirical quantitative structure-property relationships. Henry’s law solubility coefÀcients in rough but reasonable agreement with experimental values could be calculated in this manner. Information could also be obtained on the effects

USA

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Accession no.545142

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Item 391 Plastics and Rubber Weekly No.1576, 10th March 1995, p.1 PE OUTPUT RATE SET TO MULTIPLY

A thermodynamic basis is provided to aid in choosing an appropriate SCF solvent for a given fractionation, and several fractionation examples are given to reveal the potential of this emerging technique. 24 refs

A new, third generation of polyolefin manufacturing technology is promising to revolutionise production giving undreamed of output rates limited more by downstream handling than reactor capability. Newly patented advances could mean three-fold boosts to gas phase reactors, while developments in slurry and catalyst technology for PP and PE manufacture also presage improvements in both product and output. BP Chemicals recently announced its High Productivity System and Exxon’s Supercondensing Technology has just been patented. Exxon has managed to lift the liquids content in the gas Áow to between 25 and 30%. Development of the Supercritical Slurry Processes led by Neste centres upon using a propane diluent enabling process temperatures to be raised.

USA

USA

Accession no.544143 Item 392 Patent Number: WO 9413733 A1 19940623 French METHOD FOR ELIMINATING POLLUTANTS OF LOW MOLEC.WT. CONTAINED IN ELASTOMER SEALS AND PLASTIC MATERIALS Tcherevatchenkoff A; Perre C Etablissements Valois The pollutants are extracted by immersing the part in supercritical CO2 followed by a slow isothermal decompression step in the CO2 down to atmospheric pressure for between 30 min. and 16h at a temp. above 31C. EUROPEAN COMMUNITY; EUROPEAN UNION; FRANCE; WESTERN EUROPE

Accession no.533047 Item 393 Trends in Polymer Science 2, No.9, Sept.1994, p.301-7 SUPERCRITICAL FRACTIONATION OF POLYMERS AND COPOLYMERS McHugh M A; Krukonis V J; Pratt J A Johns Hopkins University; Phasex Corp. Supercritical Áuid fractionation (SCF) is a relatively rapid technique providing macrosized fractions that characterise the molecular weight and chemical composition distributions of the parent material, and which allow product performance determination of narrow molecular weight and chemical composition fractions. A review is given of the techniques used for fractionating polymers with supercritical Áuids, particularly Áuid fractionation operating schemes, selected SCF fractionations, SCF solvent selection, and applications of SCF fractionation.

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Accession no.529942 Item 394 Polymer Engineering and Science 34, No.14, July 1994, p.1148-56 GENERATION OF MICROCELLULAR POLYMERIC FOAMS USING SUPERCRITICAL CARBON DIOXIDE. II. CELL GROWTH AND SKIN FORMATION Goel S K; Beckman E J Pittsburgh,University Microcellular polymeric foam structures were generated using a pressure induced phase separation in concentrated mixtures of supercritical carbon dioxide and PMMA. The process typically generates a microcellular core structure encased by a non-porous skin, the thickness of which decreases with increasing saturation pressure. This trend can be described by a model for skin formation that is based on the diffusion rate of gas out of the sample. SigniÀcant density reductions can be achieved by changing the pressure and temperature conditions in the foaming process. Variation of cell size by temperature and pressure is described. 20 refs. USA

Accession no.523554 Item 395 Polymer Engineering and Science 34, No.14, July 1994, p.1137-47 GENERATION OF MICROCELLULAR POLYMERIC FOAMS USING SUPERCRITICAL CARBON DIOXIDE. I. EFFECT OF PRESSURE AND TEMPERATURE ON NUCLEATION Goel S K; Beckman E J Pittsburgh,University A process for synthesising microcellular polymeric foams has been studied that makes use of a pressure quench at constant temperature to initiate nucleation in a homogeneous liquid solution of supercritical carbon dioxide in PMMA. The foams thus generated invariably have a microcellular core surrounded by a relatively nonporous skin, the characteristics of which can be manipulated by changing the process conditions. 25 refs. USA

Accession no.523553 Item 396 Patent Number: EP 595184 A1 19940504 RECYCLING CELLULOSE ESTERS FROM THE WASTE FROM CIGARETTE MANUFACTURE

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References and Abstracts

Schiraldi D A Hoechst Celanese Corp. A substantial portion of cellulose ester polymer is separated from a waste stream, which includes tobacco, cellulose ester polymer and paper. The polymer is contacted with a sufficient volume of fluid to extract contaminants therefrom. The Áuid is under pressure and temperature conditions such that the Áuid is a supercritical or near supercritical Áuid. USA

Accession no.519269 Item 397 Utech ‘94: Groundwork for Growth. Conference proceedings. Hague, 22nd-24th March 1994, paper 14, pp.3. 43C6 SOLVENT EMISSION REDUCTION TECHNOLOGY FOR MOULD RELEASE OF HIGH RESILIENCE MOULDED FOAM Derderian E J; Blakemore D L OSi Specialities Inc. Edited by: Reed D; Lee C A (Crain Communications Ltd.; Rapra Technology Ltd.) OSi’s novel mould release technology (SERT or Solvent Emissions Reduction Technology) uses supercritical carbon dioxide to replace hydrocarbon solvents. Since SERT uses by-product carbon dioxide which has already been generated, no new carbon dioxide is created. The critical point for carbon dioxide occurs at rather mild conditions of temperature and pressure, 31C and 73.7 bar. Above these conditions, carbon dioxide is a supercritical Áuid with solvency properties similar to hydrocarbon solvents. This paper discusses the principles of the SERT Mould Release Technology and its performance features. It also describes the commercially available blending/ metering and spray equipment for delivering SERT mould release agents to the mould surface. 2 refs. USA

Accession no.518942 Item 398 Industrial and Engineering Chemistry Research 33, No.6, June 1994, p.1476-85 EFFECT OF RESS DYNAMICS ON POLYMER MORPHOLOGY Lele A K; Shine A D Delaware,University Details are given of the relationship between polymer morphology and the dynamics of the rapid expansion of supercritical solutions (RESS) process. Data are given for polycaprolactone, polylactic acid, PMMA, polyethyl methacrylate, and a styrene-methyl methacrylate copolymer. Experimentally observed morphologies were correlated with RESS. 42 refs.

Item 399 Angewandte Makromolekulare Chemie Vol.218, May 1994, p.69-79 German DYEING IN SUPERCRITICAL CARBON DIOXIDE: DETERMINATION OF PARAMETERS INFLUENCING THE STRUCTURAL CHARACTERISTICS OF PETP FIBRES Knittel D; Saus W; Hoger S; Schollmeyer E Deutsches Textilforschungszentrum Nord-West ev The effect of dyeing in supercritical carbon dioxide Áuids on characteristics of polymer structure was investigated using PETP Àbres. The implications of Àbre structure for successful dyeing or impregnation of Àbres in supercritical systems are discussed. 28 refs. EUROPEAN COMMUNITY; EUROPEAN UNION; GERMANY; WESTERN EUROPE

Accession no.517591 Item 400 Polymer Bulletin 32, No.5/6, May 1994, p.537-43 CARBOCATIONIC POLYMERISATIONS IN SUPERCRITICAL CARBON DIOXIDE. I. EXPLORATORY EXPERIMENTS WITH ISOBUTYLENE Pernecker T; Kennedy J P Akron,University The carbocationic polymerisation of isobutylene in supercritical carbon dioxide was achieved. It was shown that in carbon dioxide at 32.5C and about 120 bar, the 2chloro-2,4,4-trimethylpentane(TMPCl)/tin tetrachloride and TMPCl/titanium tetrachloride initiating systems led to about 30% isobutylene conversion and gave polyisobutylenes with Mn about 2000 and Mw/Mn about 2.0. It was claimed that this was the highest temp. at which isobutylene was ever polymerised to reasonably high molec.wt. products. Polymerisations at 32.5C under similar but conventional (non-living) conditions in the absence of supercritical carbon dioxide would yield only very low molec.wt. oligomers. The structure of the polymers obtained in supercritical carbon dioxide was virtually identical with those obtained at much lower temps. in conventional liquid-phase systems, indicating the presence of chain transfer to monomer in both systems. In contrast to TMPCl initiated polymerisations, the 1,3bis(2-hydroxy-2-propyl)-5-tert-butylbenzene initiator in conjunction with boron trichloride and tin tetrachloride yielded only oligomers in supercritical carbon dioxide. 22 refs. USA

Accession no.516307

USA

Accession no.517649

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Item 401 Patent Number: EP 590842 A2 19940406 PROCESS FOR PREPARING LOW MOLEC.WT. POLYMERS Dada E A; Lau W; Merritt R F; Paik Y H; Swift G Rohm & Haas Co. Polymerisation is conducted in supercritical carbon dioxide at temps. of at least 200C and pressures above 3,500 psi. The process may be continuous, semi-continuous or batch. The polymers, which have molec.wts. below 5000 and polydispersity below 2.5, are useful as detergent additives, scale inhibitors, dispersants and crystal growth modiÀers. USA

Accession no.512984 Item 402 Recycle ‘93. Conference Proceedings. Davos, 22nd-26th March 1993, paper 14/4. 8(13) INCORPORATION OF RECYCLABILITY THROUGH MOLECULAR DESIGN Beckman E J Pittsburgh,University (Maack Business Services)

coverage and cost data for conventional and supercritical Áuid plastics coating formulations are presented. 9 refs. USA

Accession no.503913 Item 404 Plastics World 52, No.1, Jan.1994, p.10 NOVEL GAS PROCESS MAKES UNIQUE FOAMS Miller B A new approach to producing thermoplastic foams has been developed at Massachusetts Institute of Technology. These microcellular foams (MCF) contain billions of micron-size voids per cubic centimetre, a structure that is claimed to retain unusually high levels in mechanical properties, even at substantial density reductions. The MCF process involves using supercritical liquid carbon dioxide, injected into the extruder barrel, as the blowing agent. Applications are foreseen in light-weighting all types of thermoplastic extrusions including proÀles, Àlms and Àbres. Commercialisation of MCF is being handled by Axiomatics Corp. MASSACHUSETTS INSTITUTE OF TECHNOLOGY; AXIOMATICS CORP. USA

The use of molecular design in different ways to incorporate recyclability into thermoplastic and thermoset materials is reviewed. Design of a material whose molecular properties allow easier separation from a mixed thermoplastic waste stream or creation of a material which degrades chemically in a predetermined way are both aspects of recyclability by molecular design. Examples are discussed. All decisions about molecular design must take into account the full life cycle of the material so that improved recyclability by molecular design does not result in a negative impact of the polymer on the environment. 35 refs. USA

Accession no.505789 Item 403 In Tune with the Newest Decorating Technologies. Retec proceedings. Nashville, Tn., 12th-13th Oct.1993, p.104-17. 8(11)34 SUPERCRITICAL FLUID SPRAY APPLICATION OF LOW-POLLUTION COATINGS FOR PLASTIC SUBSTRATES Miller W P Union Carbide Corp. (SPE,Decorating Div.; SPE,Tennessee Valley Section) The supercritical Áuid spray coating process, use of which can result in signiÀcant reductions of volatile organic content(VOC) emissions, is described. Particular attention is paid to supercritical carbon dioxide as a coating solvent, reduction of the ‘greenhouse effect’, spray generation and conditions, spray characteristics, transfer efÀciency, and suitable polymeric coating systems. Comparative VOC,

120

Accession no.501618 Item 405 Macromolecules 26, No.19, 13th Sept.1993, p.5052-60 PHASE BEHAVIOUR OF POLYMER-SUPERCRITICAL CHLORODIFLUOROMETHANE SOLUTIONS Haschets C W; Shine A D Delaware,University The phase behaviour of solutions of PMMA and polycaprolactone in supercritical chlorodiÁuoromethane was studied using a high pressure variable-volume view cell. The effect of polymer polydispersity and the critical state of the solvent on the phase behaviour was examined, and the ability of lattice Áuid and hydrogen bond models to describe the experimental data was investigated. 43 refs. USA

Accession no.494354 Item 406 Resources, Conservation and Recycling 9, No.1/2, Aug.1993, p.75-88 DENSITY-BASED SEPARATION OF THERMOPLASTICS FOUND IN THE POSTCONSUMER WASTE STREAM Super M S; Enick R M; Beckman E J Pittsburgh,University The use of near-critical CO2 and near-critical mixtures of CO2 and SF6, Áuids with highly adjustable densities, to

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References and Abstracts

separate thermoplastics found in the post-consumer waste stream from each other and contaminants was investigated. Separation of thermoplastics mixtures, including HDPE/ LDPE/PP and PVC/PETP, was carried out in a lab-scale, density-based separator. Separation efÀciency, factors affecting separation purity and favourable operating conditions and procedures were evaluated. The purity of the separated homopolymers ranged from 100 to 77 wt.%. 14 refs. USA

Accession no.490055 Item 407 Plastiques Modernes et Elastomeres 45, No.3, April 1993, p.58-60 French SUPERCRITICAL CARBON DIOXIDE: A SOLUTION TO EMISSIONS OF VOLATILE ORGANIC COMPOUNDS Moudden B Unicarb System Europe The Unicarb coating process developed by Union Carbide and Nordson is described. Carbon dioxide in the supercritical state is used in place of the usual diluents, thereby considerably reducing solvent emissions. The coatings, based on conventional resins, are applied by spraying using electrostatic guns developed by Nordson. UNION CARBIDE CHEMICALS & PLASTICS CO.INC.; NORDSON CORP. SWITZERLAND; USA; WESTERN EUROPE

Accession no.483667 Item 408 Polymer 33,No.23,1992,p.5032-9 MODELLING THE SWELLING OF CROSSLINKED ELASTOMERS BY SUPERCRITICAL FLUIDS Goel S K; Beckman E J Pittsburgh,University The mean Àeld lattice-gas model of Kleintjens et al for the free energy of mixing with an additional elastic term due to Flory was used to model the swelling of crosslinked silicones by supercritical carbon dioxide. Whereas the model reproduces well the pressure trends in both volume change and weight fraction of Áuid absorbed for the poly(dimethylsiloxane)-carbon dioxide system, the absolute predictions of weight fraction carbon dioxide absorbed are too high in the vicinity of critical pressure. 37 refs. USA

Accession no.464484

Item 409 Journal of Applied Polymer Science 46,No.8,15th Nov.1992,p.1395-9 REMOVAL OF CARBON TETRACHLORIDE FROM CHLORINATED POLYISOPRENE USING CARBON DIOXIDE Burgess A N;Jackson K ICI CHEMICALS & POLYMERS LTD. The use of supercritical carbon dioxide in the removal of residual carbon tetrachloride from chlorinated polyisoprene in a packed column was demonstrated. The effects of varying temp. and pressure on the efÀciency of extraction were examined. The data indicated that an optimum combination of pressure and temp. existed and that quite small deviations from these conditions could produce markedly poorer extraction efÀciency and lead to the destruction of the polymer particle morphology. 10 refs. EUROPEAN COMMUNITY; UK; WESTERN EUROPE

Accession no.461780 Item 410 Die Makromolekulare Chemie- Macromolecular symposia No.57,May 1992,p.305-10 CHEMICAL RECYCLING OF POLYURETHANES AND SEPARATION OF THE COMPONENTS BY SUPERCRITICAL AMMONIA Lentz H;Mormann W SIEGEN,UNIVERSITAT Chemical recycling of a RIM PU elastomer and a Áexible foam based on MDI and a polyether polyol was performed by ammonolytic cleavage of urethane and urea bonds under supercritical conditions. Resulting products were the polyols, the amines corresponding to the isocyanates used, and unsubstituted urea. Under suitable conditions the polyether polyol was completely separated from the ammonolysis products which in turn could be further separated and used for the manufacture of PU’s or for the synthesis of diisocyanates. 10 refs. (IUPAC, Macromol. Div., Int. Symp. on Recycling of Polymers. Science & Technology. Marbella, Spain, 18th-20th Sept. 1991). GERMANY

Accession no.455131 Item 411 Industrial and Engineering Chemistry Research 31,No.5,May 1992,p.1414-7 MICROCELLULAR MATERIALS VIA POLYMERISATION IN SUPERCRITICAL FLUIDS Srinivasan G;Elliott J R AKRON,UNIVERSITY A process is demonstrated whereby microcellular polymer foams can be obtained by polymerisation directly in a nearcritical diluent. Critical point drying can be effected in the

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References and Abstracts

reactor vessel in a relatively efÀcient manner. The key to the process is the choice of diluent and matching it to the polymer to be gelled and dried. Propane and Freon-22 were studied as diluents with the polymer system of poly(methyl methacrylate-co-ethylene glycol-dimethacrylate). Freon 22 proved to be the superior choice. Morphology and density of the resulting materials were comparable to microcellular foams prepared by a more conventional carbon dioxide wash and dry approach. 14 refs.

Item 414 Journal of Polymer Science : Polymer Physics Edition 29,No.8,July 1991,p.989-99 INTERACTION OF CARBON DIOXIDE GAS WITH SILICONE ELASTOMER AT HIGH AMBIENT PRESSURES Briscoe B J;Zakaria S London,Imperial College of Science,Technology & Medicine

USA

Interaction of high pressure carbon dioxide gas with a silicone elastomer, nitrile rubber and PTFE was studied. Sorption dilation was measured with piezoelectric ultrasonic transducers under gas pressures up to ca.22 MPa at 42C. The gas mass sorption was determined by a vibrating reed probe. For silicone elastomer systems, the dilation isotherm mimicked the sorption isotherm. A signiÀcant drop in the partial molar volume of the absorbed gas was observed when the carbon dioxide gas became supercritical. In the transition region the formation of discrete small high density zones of carbon dioxide in the rubber matrix was observed. Plasticisation effects of the absorbed high pressure gas were indicated by changes in the acoustic longitudinal modulus. SigniÀcant inÁation of certain polymer specimens in the desorption cycle was observed. 26 refs.

Accession no.454109 Item 412 Advanced Materials Newsletter 14,No.3,10th Feb.1992,p.4 LIGHTWEIGHT EPOXY FOAM US,DEPT.OF ENERGY US patent 5,066,684 has been assigned to the US Department of Energy for a lightweight epoxy foam material. It can have densities ranging from 35-150 mg/cc. The foam’s cell diameters are less than 1 micron. The epoxy resin is a multifunctional type mixed with a non-reactive diluent. A crosslinked epoxy gel is formed, which is mixed with a solvent, replacing the diluent. The solvent is then replaced with liquid carbon dioxide. Vaporising the carbon dioxide under supercritical conditions yields the foam. This abstract includes all the information contained in the original article. USA

Accession no.443062 Item 413 Polymeric Materials Science and Engng.Vol.60. Conference Proceedings. Dallas,Tx.,Spring 1989,p.695-9. 012 LOW DENSITY FOAMS FROM MACROPOROUS EPOXY GELS LeMay J D LAWRENCE LIVERMORE NATIONAL LABORATORY (ACS,Div.of Polymeric Materials Science & Engng.) A technology for making low density, microcellular epoxy foams is described. The foam precursor is a two phase macroporous gel made by homopolymerising an epoxy novolac oligomer in an inert diluent. Dry foam is recovered from the gel with little shrinkage by exchanging the diluent with liqueÀed carbon dioxide then processing at supercritical conditions. Foams have been made with densities ranging from 0.034 to 0.15 g/cc. SEM micrographs reveal a highly porous ramiÀed morphology that is self-similar over at least 1-2 orders of magniÀcation. The structure contains open cells with diameters ranging from 0.1 to several microns. The foams are characterised by high BET surface areas. 8 refs. USA

Accession no.439871

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Accession no.434957 Item 415 Die Makromolekulare Chemie- Macromolecular symposia No.42/43,March 1991,p.219-28 THERMAL AND RHEOLOGICAL PROPERTIES OF ACRYLIC COPOLYMERS POSSESSING CRYSTALLISABLE POLYESTER SIDE CHAINS Scholsky K M;Orier E B;Bixler K J;Stackman R W JOHNSON S.C.,& SON INC. Ring-opening of epsilon-caprolactone onto styrene-acrylic acid copolymers occurred readily at 220C. GPC and extraction experiments utilising supercritical carbon dioxide indicate that the caprolactone has grafted onto the polymer backbone as polyester side chains. DSC of these comb-like polymers showed that grafted side chains lowered Tg and contributed to crystallinity. M.p. and heat of fusion increased as a function of the amount of grafted polycaprolactone. The extent of grafting had a pronounced effect on melt rheology and crystallisation rate. 8 refs. (ACS,Div.Polym.Chem.,6th Int.Symp.on Ring-opening and Cyclopolymerisation, Boston,Mass.,22nd-27th April 1990). USA

Accession no.424716 Item 416 Plastics Technology 37,No.3,March 1991,p.29/37 NOVEL LOW-VOC PAINT TECHNOLOGY

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References and Abstracts

Schut J H Detailed information is presented on paint spraying equipment being developed by several companies for use with Unicarb technology from Union Carbide Chemicals & Plastics Co.Inc. The Unicarb technology is reported to have been developed for thinning paint with supercritical carbon dioxide. Union Carbide is also said to have licensed Àve paint companies to produce coatings compatible with the Unicarb process. Advantages and limitations of the Unicarb process are discussed in some detail. UNION CARBIDE CHEMICALS & PLASTICS CO.INC. USA

Accession no.419191

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Subject Index

Subject Index A ABS, 74 88 286 364 374 ABSORPTION, 1 22 39 56 61 193 200 212 233 374 ACRYLIC, 344 ACRYLIC ACID COPOLYMER, 121 415 ACRYLIC POLYMER, 28 147 211 246 278 301 354 371 407 ACRYLONITRILE-METHYL ACRYLATE COPOLYMER, 6 94 ACTIVATION ENERGY, 17 51 110 197 238 328 378 ADDITION REACTION, 259 ADDITIVE, 8 10 24 115 116 165 166 192 200 211 212 214 220 237 262 270 280 296 318 329 334 346 355 359 363 364 383 ADHESIVE, 43 68 211 302 ADIPIC ACID, 37 ADSORPTION, 92 184 193 AEROSOL, 193 360 370 AIBN, 28 54 60 77 88 96 100 107 111 126 213 224 AIR, 71 104 219 AIRCRAFT, 133 ALBUMIN, 193 ALCOHOLYSIS, 138 171 ALKYD RESIN, 407 AMINOCAPROIC ACID, 174 AMMONIA, 52 209 402 410 AMMONOLYSIS, 52 410 AMORPHOUS, 127 183 300 335 336 365 374 386 388 AMPHIPHILIC, 150 223 ANALYSIS, 1 2 4 19 23 37 45 55 65 75 81 83 93 96 108 124 132 135 136 160 161 176 280 294 393 405 ANIONIC POLYMERISATION, 150 256 ANTISOLVENT, 292 384 APPLICATION, 15 25 36 39 40 42 62 64 70 79 82 99 106 115 118 133 144 166 169 180 187 192 193 195 203 210 211 219 225 237 243 260 278 324 336 344 349 360 362 370 375 393 407 AQUEOUS, 109 220 269 ARGON, 237 295 AROMATIC, 1 7 9 14 83 95 107 224 276 280 282 360 362 373 ARRHENIUS’S LAW, 17 110 378

ARTIFICIAL BONE, 210 286 ATOMIC FORCE MICROSCOPY, 77 112 180 183 ATTENUATED TOTAL REFLECTION SPECTROSCOPY, 132 341 AUTOCLAVE, 7 17 116 135 193 197 222 246 312 AUTOMOTIVE APPLICATION, 42 64 82 118 133 166 192 203 344 382 402 416 AZOBISISOBUTYRONITRILE, 28 54 60 77 88 96 100 107 111 126 213 224

B BATCH POLYMERISATION, 49 155 168 401 BATCH REACTOR, 17 161 164 174 205 BENZENE, 110 125 205 238 BENZOIC ACID, 193 205 BENZOIN ETHYL ETHER, 92 BIMODAL, 89 122 135 336 BIOCIDE, 115 269 BIOCOMPATIBLE, 40 125 BIODETERIORATION, 12 39 76 125 193 210 268 269 BIOMATERIAL, 15 39 40 63 106 198 BIOMEDICAL APPLICATION, 15 193 BIOPOLYMER, 149 209 BIREFRINGENCE, 182 200 212 247 BISETHYLHEXYL PHTHALATE, 195 BISPHENOL A, 75 162 231 BISPHENOL A POLYCARBONATE, 47 281 388 BLEND, 10 11 15 48 50 55 61 69 95 101 103 107 112 127 130 155 182 199 204 206 217 224 242 251 270 274 276 284 285 286 331 333 342 355 362 380 BLIND, 253 BLOCK COPOLYMER, 88 182 257 258 267 288 335 380 BLOW EXTRUSION, 228 BLOW MOULDING, 196 203 336 BLOWING AGENT, 19 24 39 69 83 118 127 166 186 192 196 204 228 232 237 260 262 268

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275 280 338 348 357 383 395 402 404 BORNYL METHACRYLATE COPOLYMER, 168 BOTTLE, 196 373 402 BUILDING APPLICATION, 260 BULK POLYMERISATION, 136 270 BUMPER, 166 BUSINESS MACHINE, 167 BUTADIENE-ACRYLONITRILE COPOLYMER, 44 414 BUTADIENE-STYRENE COPOLYMER, 205 BUTANE, 345 380 BUTANEDIOL, 35 248 BUTYL METHACRYLATE COPOLYMER, 254 BUTYLENE COPOLYMER, 336 355

C CABLE COVERING, 151 CABLE INSULATION, 143 153 336 CABLE TIE, 203 CALORIMETRY, 5 53 84 86 111 365 CAPACITY, 143 151 336 343 355 376 CAPROLACTAM, 174 175 CAPROLACTONE, 18 CAPROLACTONE COPOLYMER, 57 415 CAPSULE, 70 193 CAR, 166 192 CARBOCATIONIC POLYMERISATION, 400 CARBON FIBRE-REINFORCED PLASTIC, 260 CARBON MONOXIDE, 172 205 CARBON TETRACHLORIDE, 409 CATALASE, 210 CATALYSIS, 336 355 376 CATALYST, 5 18 20 44 125 128 177 279 298 336 349 353 355 369 391 CATALYTIC DEGRADATION, 109 CATHETER, 195 CATIONIC POLYMERISATION, 256 299 353 387 400 CAVITY PRESSURE, 192 CAVITY TRANSFER MIXER, 204 260

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Subject Index

CELL COLLAPSE, 319 CELL DENSITY, 22 26 31 32 116 127 249 303 319 348 CELL GROWTH, 4 22 26 167 192 394 CELL MORPHOLOGY, 22 26 31 32 CELL SIZE, 26 31 32 95 97 116 144 166 167 196 229 232 249 276 303 319 338 348 383 388 394 404 CELL STRUCTURE, 4 22 26 29 31 32 116 144 196 229 268 333 338 413 CELLULOSE, 209 320 396 407 CELLULOSE ACETATE, 356 CELLULOSE ACETATE BUTYRATE, 374 407 CEMENT KILN, 102 CFC, 218 347 CFC FREE, 377 CFC REPLACEMENT, 193 310 CHAIN TRANSFER, 9 122 135 347 400 CHAIN TRANSFER AGENT, 9 28 390 CHARACTERISATION, 5 16 19 20 34 35 53 55 59 61 83 84 92 93 95 103 124 125 183 233 258 289 327 393 411 CHEMICAL MODIFICATION, 43 44 63 83 84 95 109 162 171 197 248 259 270 279 301 350 364 402 CHEMICAL PLANT, 332 CHEMICAL RECYCLING, 38 102 171 172 189 197 248 271 277 334 CHEMICAL SENSOR, 216 225 CHEMICAL STRUCTURE, 2 3 5 15 35 45 51 52 57 59 77 92 106 119 125 128 157 163 177 190 213 239 240 256 258 267 295 315 336 341 349 355 359 CHEMICAL VAPOUR DEPOSITION, 180 CHLORODIFLUOROMETHANE, 16 27 380 405 CHLOROFLUOROCARBON, 218 347 CHLOROFLUOROHYDROCARBON, 204 237 280 CHLOROFORM, 165 CHLOROTRIFLUOROETHYLENE COPOLYMER, 148 CHLOROTRIFLUOROMETHANE, 240 CHLOROTRIMETHYLPENTANE, 400

126

CHROMATOGRAPHY, 1 3 5 16 17 18 20 27 34 35 36 37 51 52 73 76 84 85 86 100 110 111 119 124 125 128 135 136 146 157 161 171 174 190 195 205 232 234 238 239 248 250 256 261 267 271 273 295 311 314 326 327 379 CIGARETTE, 396 CLAMP FORCE, 42 166 167 192 CLAMPING UNIT, 178 CLAY, 4 22 32 33 53 69 78 116 CLEANING, 18 117 360 CLOSED CELL, 42 83 116 250 276 331 CLOUD POINT, 137 155 173 240 289 335 398 405 COALESCENCE, 217 268 278 COATED FABRIC, 243 COATING, 46 115 154 194 198 211 225 235 236 244 254 269 270 278 300 302 322 336 344 403 407 416 COCATALYST, 336 355 376 COINJECTION, 29 167 COLLOID, 157 267 COLLOIDAL STABILITY, 28 297 COMMERCIAL INFORMATION, 153 343 355 376 416 COMPACT DISC, 286 COMPATIBILITY, 182 212 284 COMPOSITE, 12 22 30 32 40 58 64 65 69 76 78 102 108 116 133 172 187 201 260 296 313 333 349 364 369 386 402 COMPOSITION, 11 22 30 36 62 78 98 103 127 137 202 217 277 291 372 COMPOUNDING, 12 217 251 COMPRESSION MOULDING, 19 65 COMPUTER SIMULATION, 40 114 388 CONCENTRATION DEPENDENCE, 11 20 21 22 78 257 CONDENSATION POLYMERISATION, 191 264 270 279 CONDUCTIVE FIBRE, 209 CONDUCTIVE POLYMER, 63 350 CONFOCAL LASER SCANNING MICROSCOPY, 134 CONSTRAINED GEOMETRY CATALYST, 336 355 CONTAMINANT, 373 396 CONTAMINATION, 250 406

CONTINUOUS, 89 117 127 222 274 332 356 CONTINUOUS POLYMERISATION, 89 122 145 151 168 401 CONTINUOUS STIRRED TANK REACTOR, 122 CONTROLLED-RELEASE, 99 106 193 258 386 CONVERSION, 7 11 111 197 222 271 320 400 COOLING, 96 166 192 204 237 348 391 COPOLYMER COMPOSITION, 20 60 67 91 148 377 388 CORE, 394 395 CORE-SHELL, 181 COSMETICS, 166 COSOLVENT, 43 68 70 88 128 193 COST, 42 64 144 167 192 203 204 209 253 259 260 286 339 371 376 403 COUNTER-ROTATING EXTRUDER, 373 CRACKING, 163 261 336 CRITICAL POINT, 170 248 411 CRITICAL PRESSURE, 275 348 408 CRITICAL SOLUTION TEMPERATURE, 155 405 CRITICAL TEMPERATURE, 175 275 320 CROSSLINK, 160 226 402 CROSSLINK DENSITY, 45 119 CROSSLINKED, 111 149 170 205 263 408 CROSSLINKING, 58 92 111 131 170 216 230 CRYSTALLINITY, 23 54 61 71 84 90 91 104 127 183 185 200 208 247 252 258 273 281 287 290 336 376 379 388 415 CRYSTALLISATION, 33 47 48 63 64 80 104 170 206 231 245 273 281 283 314 345 365 415 CURING, 216 269 407 CURING AGENT, 45 119 131 165 331 CYCLE TIME, 42 64 166 167 192 203 CYCLOHEXANONE OXIME, 175 CYCLOHEXENE OXIDE, 309

D DEBROMINATION, 162 DECHLORINATION, 109 DECOMPOSITION, 38 96 160 162

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Subject Index

172 174 175 204 259 293 332 349 368 DECOMPOSITION PRODUCT, 37 160 161 162 163 164 259 265 277 DECOMPRESSION, 117 385 392 407 414 DEGRADABLE, 12 125 210 268 DEGRADATION, 10 13 34 35 88 98 109 110 138 171 197 205 261 293 317 318 363 402 DEGRADATION PRODUCT, 17 138 197 271 293 320 DEGREE OF POLYMERISATION, 11 378 387 389 390 392 393 398 400 401 DEGREE OF SWELLING, 66 152 219 DEMIXING, 378 405 DEMOULDING, 166 DENSIFICATION, 319 DENSITY, 24 49 66 88 95 97 110 116 164 170 192 193 197 218 237 240 255 260 336 338 361 378 381 383 388 394 395 402 404 406 411 412 DEPOLYMERISATION, 17 34 35 73 88 171 197 205 248 265 277 349 402 DEPRESSURISED, 140 193 221 278 338 DESIGN, 41 64 90 97 178 192 215 322 357 376 DESORPTION, 1 14 61 117 184 388 414 DETERGENT, 373 401 DEVOLATILISATION, 242 351 DEVULCANISATION, 2 45 119 165 DIAMINOTOLUENE, 343 DICHLOROMETHANE, 5 106 DIE, 72 201 202 260 268 333 339 DIE DESIGN, 196 DIELECTRIC CONSTANT, 83 151 193 388 DIETHYL PEROXYDICARBONATE, 89 122 135 222 DIETHYLHEXYL PHTHALATE, 195 DIFFERENTIAL THERMAL ANALYSIS, 5 19 23 47 51 53 55 61 66 71 80 81 84 90 107 112 119 121 125 158 183 212 239 273 314 316 379 398 DIFFRACTION, 19 23 53 54 61 69 76 80 DIFFUSION, 14 51 75 88 90 92 99

117 139 152 159 164 165 182 183 186 192 193 200 212 214 219 220 247 268 316 337 388 404 414 DIFFUSIVITY, 14 88 92 95 337 DIFLUOROETHANE, 141 282 DILATION, 66 90 414 DILUENT, 88 263 336 376 383 391 407 411 412 DIMENSIONAL STABILITY, 24 144 167 192 286 375 DIMETHYL ACRYLAMIDE COPOLYMER, 96 DIMETHYL ETHER, 156 DIMETHYL FORMAMIDE, 54 DIMETHYL SILOXANE COPOLYMER, 257 DIMETHYL TEREPHTHALATE, 17 34 35 171 197 248 265 368 DIMETHYLACRYLAMIDE COPOLYMER, 96 DIPHENYL DISULFIDE, 119 165 DIPHENYL ETHER, 38 DISPERSE DYE, 176 DISPERSE PHASE, 242 333 DISPERSE RED 1, 214 DISPERSION, 12 43 49 68 131 187 193 199 217 321 324 DISPERSION COPOLYMERISATION, 96 DISPERSION POLYMERISATION, 7 28 59 67 86 88 96 111 147 157 181 223 233 246 255 266 267 270 278 288 289 291 297 307 323 352 353 354 DISSOLUTION, 44 164 242 268 292 348 380 DISSOLVING, 141 333 DIVINYL BENZENE, 131 DOMESTIC APPLIANCE, 166 DOOR HANDLE, 286 DOPING, 108 350 373 DRAWING, 71 104 208 252 287 315 DRUG DELIVERY, 106 193 258 386 DWELL TIME, 122 DYE, 176 179 200 212 214 220 227 247 315 337 346 399 DYEING, 23 176 200 209 212 270 315 316 329 337

E ELASTIC MODULUS, 107 130 230 336 375 ELASTIC PROPERTIES, 141 142

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316 ELASTOMER, 2 28 44 45 64 68 82 90 92 115 119 130 137 165 166 187 192 199 203 204 205 216 225 237 294 299 313 321 323 324 325 326 327 330 331 332 334 344 351 353 355 360 361 366 367 371 372 377 378 380 385 387 388 392 397 401 ELECTRICAL APPLICATION, 64 166 187 ELECTRICAL CONDUCTIVITY, 58 63 93 108 187 350 ELECTRICAL PROPERTIES, 63 108 187 193 350 388 ELECTROCHEMICAL POLYMERISATION, 93 ELECTRON MICROGRAPH, 111 127 213 ELECTRON MICROSCOPY, 4 19 23 29 55 83 93 130 150 170 173 183 184 232 233 294 296 ELECTRONIC APPLICATION, 166 180 192 382 ELONGATION, 143 151 250 375 EMISSION, 344 407 EMISSION CONTROL, 347 EMULSION, 115 134 269 304 EMULSION POLYMERISATION, 49 88 134 150 155 270 329 353 ENCAPSULATION, 29 193 313 370 END GROUP, 28 84 138 213 ENERGY CONSERVATION, 181 259 ENERGY SAVING, 167 ENGINEERING APPLICATION, 42 88 166 192 204 221 260 ENVIRONMENT, 88 102 181 188 204 254 269 308 311 318 325 344 349 368 369 397 402 403 407 ENVIRONMENTALLY FRIENDLY, 18 115 203 211 329 343 358 371 ENZYME, 18 99 209 EPDM, 331 334 355 EPOXY NOVOLAC RESIN, 413 EPOXY RESIN, 73 102 162 382 402 407 412 EPSILON CAPROLACTAM, 174 175 EPSILON-CAPROLACTONE, 18 EQUIPMENT, 25 222 397 416 ETHANOL, 70 80 187 190 220 ETHYL METHACRYLATE COPOLYMER, 239 ETHYLBENZENE, 205

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Subject Index

ETHYLENE, 5 393 ETHYLENE-BUTYLENE COPOLYMER, 336 355 ETHYLENE COPOLYMER, 336 355 ETHYLENE GLYCOL, 34 60 79 138 171 197 265 349 368 411 ETHYLENE-HEXENE COPOLYMER, 336 355 ETHYLENE-MALEIC ANHYDRIDE COPOLYMER, 11 ETHYLENE-METHYL ACRYLATE COPOLYMER, 199 ETHYLENE-OCTENE COPOLYMER, 355 ETHYLENE OXIDE, 279 ETHYLENE-PROPYLENE COPOLYMER, 26 355 ETHYLENE-PROPYLENEDIENE TERPOLYMER, 331 334 355 ETHYLENE-STYRENE COPOLYMER, 355 ETHYLENE-VINYL ALCOHOL COPOLYMER, 402 EXCLUSION CHROMATOGRAPHY, 52 84 136 146 190 232 256 314 327 EXFOLIATION, 32 EXPANSION, 70 90 154 193 278 356 EXTRACTION, 1 56 80 121 193 227 241 270 279 300 344 364 370 372 409 EXTRUDER, 2 12 26 79 123 127 199 201 204 217 228 242 260 274 284 285 333 339 357 EXTRUSION, 2 12 26 69 72 103 105 113 114 123 127 142 143 196 199 201 202 203 204 217 218 228 237 242 245 250 251 260 262 268 274 284 285 333 336 339 404 EXTRUSION BLOW MOULDING, 196 EXTRUSION BLOWING, 228 EXTRUSION COMPOUNDING, 217 EXTRUSION MIXING, 103 199 242 284 285

F FABRIC, 179 209 227 243 315 FIBRE, 23 71 87 102 104 176 179 200 208 209 212 227 230 247

128

252 287 315 316 329 336 346 356 399 404 FIBRE-REINFORCED PLASTIC, 65 172 260 FIBRILLATION, 247 FILLER, 33 40 53 69 76 78 102 116 123 217 FILM, 14 44 46 79 143 151 180 183 194 219 220 254 278 336 337 344 404 FLAME PROOFING, 24 296 363 364 FLAME RETARDANCE, 24 296 363 364 FLAMMABILITY, 12 204 FLASHING, 292 FLEXURAL PROPERTIES, 12 65 143 199 237 336 FLOW, 114 116 192 262 348 378 FLOW RATE, 2 105 151 FLOW REACTOR, 161 FLUID, 88 136 193 321 337 344 FLUID BED, 193 336 376 FLUORINATED, 26 137 289 FLUORINATED ETHYLENEPROPYLENE COPOLYMER, 143 377 FLUOROACRYLATE POLYMER, 354 FLUOROELASTOMER, 137 FLUOROPOLYMER, 46 62 88 122 137 143 148 150 151 153 180 222 223 240 244 266 272 330 335 353 375 377 387 FOAM, 4 12 19 22 24 33 39 48 63 64 69 76 82 83 97 114 116 118 127 133 134 141 144 155 166 167 178 186 187 188 192 203 204 218 228 229 232 237 249 250 253 260 262 263 268 275 276 280 303 319 331 338 345 348 357 383 394 395 397 404 410 411 412 413 FOAMING, 22 41 95 127 142 204 338 FOAMING AGENT, 19 24 39 69 83 118 127 166 186 192 196 204 228 232 237 260 262 268 275 280 338 348 357 FOAMING TEMPERATURE, 127 FOURIER TRANSFORM INFRARED SPECTROSCOPY, 2 10 23 34 35 55 92 98 125 150 160 175 180 213 214 219 248 283 294 339 377 385 FRACTIONATION, 119 234 270 290 314 327 362 379 393 FRACTURE MORPHOLOGY, 4 7

15 23 27 29 33 40 49 50 54 55 57 58 65 67 69 76 81 83 87 93 106 107 112 114 121 130 134 157 173 195 199 212 216 239 242 246 249 251 255 266 267 274 331 342 345 350 359 FREE RADICAL COPOLYMERISATION, 96 168 377 FREE RADICAL POLYMERISATION, 5 7 9 49 55 59 61 67 89 96 122 130 131 136 145 146 168 190 191 213 239 263 288 299 307 310 311 312 328 377 389 390 FREE VOLUME, 141 142 193 215 227 361 378 FREON, 411 FURNITURE, 166 407

G GALACTOSIDASE, 210 GAS ABSORPTION, 22 385 408 GAS-ASSISTED, 166 192 GAS CHROMATOGRAPHY, 1 34 35 37 73 85 161 171 174 205 271 280 GAS DIFFUSION, 192 268 388 GAS INJECTION, 12 133 166 167 GAS INJECTION MOULDING, 166 192 286 GAS PERMEABILITY, 388 414 GAS-PHASE, 167 172 193 344 376 GAS PHASE POLYMERISATION, 67 336 355 391 GAS PRESSURE, 192 286 GAS SOLUBILITY, 169 335 366 388 GAS SORPTION, 366 385 388 GEL, 149 170 331 412 413 GEL PERMEATION CHROMATOGRAPHY, 3 5 16 17 18 20 27 36 51 76 86 100 110 111 119 124 125 128 135 157 195 234 238 239 248 250 261 267 273 295 311 327 379 GEL SPINNING, 315 316 GLASS FIBRE-REINFORCED PLASTIC, 64 102 260 349 GLASS TRANSITION TEMPERATURE, 43 48 68 76 83 85 90 94 112 114 121 141 152 193 199 218 231 254 263 281 348 383 398 415 GLASSY, 206 214 341 GLYCIDYL METHACRYLATE, 111 168 173

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Subject Index

GLYCOL COPOLYMER, 59 GLYCOLIDE COPOLYMER, 39 106 169 210 258 GRAVIMETRIC ANALYSIS, 7 14 53

H HARDNESS, 25 151 203 HCFC, 204 237 280 HEAT DEGRADATION, 45 109 163 164 238 293 295 296 356 HEATING, 1 96 160 365 HELIUM, 297 354 HEPTAFLUOROPROPANE, 372 HEPTANE, 345 HETEROGENEOUS POLYMERISATION, 49 193 HEXAFLUOROPROPYLENE COPOLYMER, 46 91 240 377 HFA-134A, 141 282 HFC, 244 280 321 HIGH DENSITY POLYETHYLENE, 33 88 204 237 260 261 314 336 355 373 376 381 393 406 HIGH PERFORMANCE LIQUID CHROMATOGRAPHY, 59 161 171 174 295 HIGH PRESSURE, 132 155 158 172 182 208 248 252 259 332 334 366 405 414 HIGH TEMPERATURE, 151 172 203 248 259 332 334 376 HOMOGENEOUS, 122 222 270 321 345 353 380 395 HOT MELT ADHESIVE, 302 HOT WATER, 332 HOUSING, 203 286 HYDROCHLOROFLUOROCARBON, 204 237 280 HYDROFLUOROCARBON, 244 280 321 HYDROLYSIS, 124 162 174 259 320 363 HYDROLYTIC DEGRADATION, 37 161 162 259 293 HYDROPHILIC, 49 92 150 211 223 301 HYDROPHOBIC, 150 193 223 269 315 HYDROXYAPATITE, 40 210 HYDROXYBENZENE, 75 205 271

I IMMISCIBLE, 15 127 242 380

IMPACT PROPERTIES, 12 31 32 131 199 224 336 IMPLANT, 40 IMPREGNATION, 48 55 61 108 112 132 193 206 214 219 220 224 245 269 270 344 399 IMPURITY, 360 373 INDOMETHACIN, 106 370 INFRARED SPECTRA, 3 10 23 61 80 92 107 126 132 138 171 191 213 283 294 341 INITIATOR, 10 16 21 27 28 40 49 54 55 60 61 86 87 88 89 92 96 100 107 111 120 122 126 131 135 145 157 207 213 222 224 230 239 256 299 307 310 330 INJECTION MOULD, 166 192 INJECTION MOULDED, 31 32 129 INJECTION MOULDING, 4 12 25 29 31 32 41 42 48 64 97 101 118 129 144 166 167 178 188 192 203 229 245 286 336 INJECTION MOULDING MACHINE, 29 42 105 166 192 INJECTION PRESSURE, 42 166 167 192 INJECTION RATE, 70 260 INJECTION SPEED, 4 31 41 97 129 167 INSULATION, 83 143 153 260 INTEGRAL SKIN FOAM, 29 394 395 INTERACTION, 8 11 14 193 219 240 315 335 374 375 388 INTERCALATION, 33 53 78 ISOTACTIC, 10 36 331 336 345 355 ISOTHERM, 88 405 414 ISOTHERMAL, 316 392 393

K KINETICS, 9 16 17 21 49 51 61 75 92 110 136 146 147 152 182 207 222 246 248 290 355

L LACTIDE COPOLYMER, 39 106 169 210 258 LANGIVIN EQUATION, 17 61 66 72 85 92 98 101 110 134 152 193 LATICES, 139 155 211 233 LICENCE, 42 203 237 LINEAR LOW DENSITY POLYETHYLENE, 88 170 183

© Copyright 2004 Rapra Technology Limited

185 237 336 355 376 393 LIQUID CARBON DIOXIDE, 43 49 68 176 223 264 LIQUID CHROMATOGRAPHY, 59 161 171 174 295 326 LIQUID CRYSTAL, 209 LITHOGRAPHY, 62 198 254 270 LIVING POLYMERISATION, 9 36 150 312 LOW DENSITY POLYETHYLENE, 88 103 113 123 204 224 237 296 336 355 381 406 LOWER CRITICAL SOLUTION TEMPERATURE, 155 405

M MACHINERY, 12 29 42 79 105 127 144 166 178 188 192 201 217 228 260 274 285 332 333 339 357 373 406 416 MALEIC ANHYDRIDE COPOLYMER, 10 98 116 MASS POLYMERISATION, 136 270 MASS SPECTRA, 1 37 174 MATERIAL REPLACEMENT, 82 88 181 204 269 310 329 344 402 MATRIX, 50 83 131 193 214 337 MEASUREMENT, 44 90 92 98 105 117 119 152 280 333 337 357 383 MECHANISM, 163 197 248 276 293 361 MEDICAL APPLICATION, 15 25 39 40 99 166 169 192 193 195 360 386 MEDIUM-DENSITY POLYETHYLENE, 336 MELAMINE RESIN, 407 MELT, 10 33 79 140 141 237 268 282 351 MELT FLOW, 10 30 192 MELT FLOW INDEX, 167 222 MELT FLOW RATE, 98 143 MELT RHEOLOGY, 6 30 94 142 217 MELT STRENGTH, 204 228 260 MELT TEMPERATURE, 4 6 94 97 129 167 183 192 201 231 260 MELT VISCOSITY, 6 26 30 94 127 142 192 217 274 282 339 361 415 MELT VISCOSITY INDEX, 167 222 MELTING, 47 66 80 90 91 132 316

129

Subject Index

348 MELTING POINT, 116 151 158 281 377 379 393 398 415 MELTING TEMPERATURE, 23 66 91 248 MERCURY POROSIMETRY, 134 184 METALLOCENE, 170 336 355 METERING, 275 397 METHACRYLATE COPOLYMER, 59 62 67 136 168 223 254 METHACRYLIC ESTER COPOLYMER, 59 62 67 136 168 223 254 METHANOL, 17 34 35 79 160 171 197 248 265 271 277 349 356 368 METHANOLYSIS, 171 197 248 METHYLBENZENE, 9 27 43 68 88 128 205 METHYL METHACRYLATE, 59 213 METHYL METHACRYLATE COPOLYMER, 60 67 96 239 352 380 398 402 411 MICROCAPSULE, 70 193 MICROCELLULAR, 4 12 29 31 32 41 42 64 83 95 97 118 127 129 140 142 144 155 166 167 178 192 196 203 218 229 232 249 253 263 270 303 319 338 383 394 395 404 411 413 MICROEMULSION, 115 269 304 MICROENCAPSULATION, 313 370 MICROFIBRIL, 384 MICROLITHOGRAPHY, 62 MICROPARTICLE, 111 193 370 MICROPOROUS, 115 193 MICROSPHERE, 27 193 225 345 384 MICROSTRUCTURE, 19 65 97 107 128 129 156 177 221 250 283 MIRROR, 167 286 MISCIBILITY, 127 155 182 302 378 MIXER, 204 260 284 MIXING, 53 103 199 242 274 284 285 388 405 MODIFICATION, 41 84 263 270 301 MOLECULAR STRUCTURE, 2 3 5 15 35 45 51 52 57 59 77 92 96 106 119 125 126 128 157 163 177 190 213 239 240 256 258 267 290 295 315 336 341 349 355 359 379 388 400 402

130

MOLECULAR WEIGHT, 3 5 7 9 10 15 16 18 20 21 27 36 50 52 54 67 70 71 75 76 79 84 86 87 89 98 100 110 120 122 125 128 130 135 138 145 146 148 152 156 160 164 165 173 177 193 207 213 222 230 232 234 239 257 261 266 267 273 276 281 288 289 290 306 311 312 314 334 335 336 352 355 361 362 378 387 389 390 392 393 398 400 401 405 MOLECULAR WEIGHT DISTRIBUTION, 27 89 110 120 122 128 135 139 146 238 250 257 276 314 328 336 355 376 MONOETHYLENE GLYCOL, 34 79 138 171 197 265 349 MONOMER, 17 38 61 89 92 111 136 213 349 350 369 MONOMER RECOVERY, 88 265 MONTMORILLONITE, 19 22 30 33 53 78 MORPHOLOGY, 4 7 15 23 27 29 33 40 49 50 54 55 57 58 65 67 69 76 78 81 83 87 93 103 106 107 111 112 114 121 127 130 134 140 154 155 157 170 173 177 183 184 185 195 199 212 213 216 217 239 242 246 249 251 255 266 267 274 283 285 287 331 333 342 345 350 359 370 374 377 384 390 398 411 413 MOULD, 166 192 MOULD RELEASE, 397 MOULD TEMPERATURE, 129 167 MOULDING, 19 65 167 203 237 295 318 MOULDING PRESSURE, 166 192 MULTI-COMPONENT, 155 166 182 MULTI-MATERIAL MOULDING, 166 MULTIPLE INJECTION MOULDING, 166

N NANOCOMPOSITE, 4 12 19 22 30 32 33 53 78 116 133 296 NANOPARTICLE, 4 30 33 46 49 198 NANOSTRUCTURE, 50 63 NAPHTHALENE, 88 315 373 405 NAPHTHALENEDICARBOXYLIC

ACID, 368 NATURAL RUBBER, 119 NBR, 44 NITRILE RUBBER, 44 414 NITROGEN, 32 51 75 155 166 167 184 192 203 229 237 348 363 NON-POLAR, 43 68 NON-POROUS, 394 395 NOZZLE, 41 166 292 NUCLEAR MAGNETIC RESONANCE, 5 20 27 36 45 57 59 119 124 125 126 128 145 157 160 177 239 241 256 258 261 298 379 NUCLEATION, 4 19 26 49 167 192 196 221 246 276 338 383 395 NYLON, 10 32 55 88 161 166 167 208 264 292 320 NYLON-11, 186 NYLON-12,12, 55 NYLON-6, 4 10 11 61 174 175 NYLON-6-6, 12 37 65 203 208 252 375

O OFFICE EQUIPMENT, 166 192 OIL RESISTANCE, 43 68 243 OPEN-CELLED, 345 OPTICAL MICROSCOPY, 61 65 97 152 183 212 OPTIMISATION, 38 67 92 111 370 376 ORTHOPAEDIC APPLICATION, 263

P PACKAGING, 1 166 237 260 368 381 402 PARTICLE FORMATION, 147 246 270 PARTICLE SIZE, 28 76 88 103 106 111 121 154 157 193 213 223 246 255 257 266 267 292 297 331 354 370 390 PARTICLE SIZE DISTRIBUTION, 70 147 154 173 292 297 354 370 PATENT, 25 42 237 336 412 PENTANE, 302 405 PEROXIDE, 88 98 122 222 331 PHARMACEUTICAL APPLICATION, 70 99 106 169 193 210 324 360 370 PHASE BEHAVIOUR, 8 49 96 155 156 182 199 240 244 337 393

© Copyright 2004 Rapra Technology Limited

Subject Index

405 PHASE SEPARATION, 50 63 134 241 249 331 394 PHASE STRUCTURE, 103 112 199 PHENOL, 75 205 271 PHENOLIC RESIN, 102 172 271 295 317 318 407 PHOTOLITHOGRAPHY, 62 254 PHOTOPOLYMERISATION, 40 PHOTORESIST, 62 198 254 PIPE, 237 336 PLASTICISATION, 6 26 66 81 85 90 91 117 142 158 166 193 206 208 212 215 220 284 305 341 347 374 385 395 414 PLASTICISER, 91 117 142 185 186 215 218 270 305 339 340 355 386 PLASTICISING, 121 178 PLASTICS WASTE, 74 172 402 POLAR, 43 68 POLARITY, 126 128 223 370 374 388 POLYACRYLAMIDE, 134 POLYACRYLATE, 8 88 136 211 266 278 335 POLYACRYLIC ACID, 55 61 193 311 390 POLYACRYLONITRILE, 54 87 120 126 267 384 POLYAMIDE, 10 32 55 88 161 166 167 208 229 264 292 320 375 POLYAMIDE-11, 186 POLYAMIDE-12,12, 55 POLYAMIDE-6, 4 10 11 61 174 175 POLYAMIDE-6,6, 12 37 65 252 375 POLYARAMIDE, 346 POLYARYL KETONE, 346 POLYARYLATE, 219 POLYARYLETHERKETONE, 260 POLYARYLSULFIDE, 346 POLYBISETHOXYMETHYLOXE TANE, 387 POLYBUTADIENE, 92 137 140 POLYBUTYL ACRYLATE, 306 POLYBUTYL METHACRYLATE, 152 POLYBUTYLENE, 400 POLYBUTYLENE SUCCINATE, 268 POLYBUTYLENE TEREPHTHALATE, 35 84 248 POLYCAPROAMIDE, 4 10 11 61 POLYCAPROLACTAM, 4 10 11 61

POLYCAPROLACTONE, 18 193 207 256 398 405 POLYCARBONATE, 51 52 74 75 85 88 97 110 117 129 166 221 228 231 260 286 293 309 318 374 388 404 POLYCONDENSATION, 191 264 270 279 POLYCYANOACRYLATE, 382 POLYDIHYDROPERFLUOROOC TYL ACRYLATE, 46 266 354 POLYDIMETHYLAMINOETHYL METHACRYLATE, 67 POLYDIMETHYLPHENYLENE OXIDE, 298 POLYDIMETHYLSILOXANE, 7 28 117 141 216 225 234 246 278 327 361 378 393 408 POLYDIMETHYLSILOXANE METHACRYLATE, 60 111 147 POLYDISPERSITY, 5 16 18 20 122 135 232 276 327 394 401 405 POLYEPOXIDE, 73 102 162 POLYETHER KETONE, 38 73 POLYETHER URETHANE, 366 POLYETHER-ETHERKETONE, 38 80 83 228 237 365 POLYETHERIMIDE, 374 POLYETHYL ACRYLATE, 306 POLYETHYL HEXYL ACRYLATE, 211 278 306 POLYETHYL METHACRYLATE, 398 POLYETHYLACRYLAMIDE, 150 POLYETHYLENE, 5 33 50 56 71 88 103 104 112 113 123 149 160 163 164 166 170 183 185 201 204 208 224 230 237 242 260 261 285 296 314 315 316 320 333 336 355 373 375 376 381 391 393 402 405 406 POLYETHYLENE GLYCOL, 70 POLYETHYLENE GLYCOL METHACRYLATE, 60 POLYETHYLENE NAPHTHALENE DICARBOXYLATE, 277 POLYETHYLENE OXIDE, 53 158 POLYETHYLENE TEREPHTHALATE, 23 34 79 138 171 176 197 200 208 209 220 221 227 247 250 265 279 287 300 315 320 349 368 369 374 375 381 399 402 406 POLYETHYLHEXYL ACRYLATE, 211 278 306 POLYFLUOROETHYLENE, 26 88 151 310

© Copyright 2004 Rapra Technology Limited

POLYGLYCIDYL METHACRYLATE, 111 181 POLYIMIDE, 359 POLYIMINOCARBONATE, 402 POLYISOBORNYL METHACRYLATE, 60 POLYISOPRENE, 45 137 165 409 POLYKETONE, 80 POLYLACTIC ACID, 12 193 398 POLYLACTIDE, 16 27 57 76 99 210 370 POLYMER CRACKING, 334 POLYMERIC STABILISER, 7 28 60 67 147 213 289 354 POLYMERIC SURFACTANT, 49 88 96 266 278 352 POLYMERISATION CATALYST, 18 128 177 279 298 336 353 355 POLYMERISATION INITIATOR, 10 21 27 28 40 54 55 60 61 86 87 88 89 96 100 107 111 120 122 126 135 145 157 207 213 222 224 239 256 299 310 330 400 POLYMERISATION KINETICS, 9 16 21 49 51 75 136 146 147 207 222 246 355 POLYMERISATION MECHANISM, 18 27 40 49 51 54 57 69 86 87 92 100 139 146 157 190 239 255 256 267 273 298 308 328 336 POLYMERISATION PRESSURE, 7 67 96 135 266 321 336 401 POLYMERISATION RATE, 9 21 75 122 177 222 POLYMERISATION REACTOR, 3 122 336 355 411 POLYMERISATION TEMPERATURE, 7 96 122 135 224 336 400 401 POLYMERISATION TIME, 10 67 75 111 120 147 246 POLYMERISATION YIELD, 3 18 POLYMETHACRYLATE, 40 50 67 77 136 147 223 382 POLYMETHYL ACRYLATE, 8 306 POLYMETHYL MERCAPTOACETAMIDE, 155 POLYMETHYL METHACRYLATE, 21 28 36 58 59 65 70 78 85 86 88 90 106 112 117 127 132 139 141 147 152 155 157 159 181 199 213 214 217 233 246 251 255 274

131

Subject Index

284 288 297 304 307 328 337 341 342 352 354 374 379 383 394 395 398 405 POLYNORBORNENE, 128 POLYOLEFIN, 7 9 10 13 14 95 107 116 149 204 208 212 224 276 280 282 290 315 316 320 336 344 345 355 375 376 381 391 400 POLYOLEFIN ELASTOMER, 355 POLYORGANOSILOXANE, 7 28 58 88 115 117 216 225 226 234 246 278 POLYOXETANE, 299 387 POLYOXYETHYLENE, 53 POLYOXYMETHYLENE, 375 POLYPHENYLACETYLENE, 177 POLYPHENYLENE OXIDE, 117 167 228 298 374 POLYPHENYLENE SULFIDE, 237 260 POLYPHENYLOXAZOLINE, 256 POLYPHENYLSULFONE, 228 POLYPHOSPHAZENE, 335 POLYPROPYLENE, 10 12 13 64 88 98 101 105 107 116 131 166 167 176 203 204 212 228 237 260 315 316 331 336 345 355 375 376 381 391 402 406 POLYPYRROLE, 58 93 108 187 350 POLYSILOXANE, 7 28 49 88 96 115 216 226 335 POLYSTYRENE, 7 9 14 19 26 29 30 41 58 61 69 72 85 88 90 95 103 107 108 114 127 130 131 141 142 146 155 166 167 181 182 190 199 202 204 217 224 232 233 237 238 242 251 260 274 276 280 282 283 284 285 289 312 319 333 336 338 340 342 355 357 374 384 402 404 POLYSULFONE, 374 POLYTETRAFLUOROETHYLENE, 26 88 151 310 367 389 POLYTRIFLUOROCHLOROETH YLENE, 58 POLYTRIMETHYLENE TEREPHTHALATE, 17 33 POLYTRIMETHYLOLPROPANE TRIMETHACRYLATE, 184 POLYURETHANE, 24 187 259 303 344 374 382 397 402 407 410 POLYURETHANE ELASTOMER, 385 POLYVINYL ACETATE, 8 291

132

POLYVINYL ALCOHOL, 358 POLYVINYL CHLORIDE, 88 100 117 195 237 367 374 381 402 404 406 POLYVINYL CYANIDE, 54 87 267 POLYVINYL ETHER, 387 POLYVINYL ISOBUTYL ETHER, 387 POLYVINYL PYRROLIDONE, 49 181 257 266 POLYVINYL TRIFLUOROACETATE, 358 POLYVINYLBENZENE, 26 30 41 85 103 131 141 142 155 182 199 202 204 217 242 274 POLYVINYLIDENE FLUORIDE, 66 81 88 89 90 91 122 127 135 155 194 222 240 375 POLYVINYLPYRROLIDONE, 49 181 257 266 PORE SIZE, 77 134 170 263 345 PORE STRUCTURE, 149 319 POROSITY, 4 39 40 76 77 89 115 134 149 166 170 263 269 276 345 413 POROUS, 58 63 99 115 184 193 198 249 263 270 POWDER COATING, 115 269 300 322 407 PRECIPITATION, 88 193 292 324 384 PRECIPITATION POLYMERISATION, 54 87 89 120 122 126 135 145 222 270 323 353 390 PRESSURE, 5 13 14 16 17 44 47 66 70 84 88 89 90 91 92 95 111 119 120 121 128 138 140 142 149 152 156 158 159 173 182 192 193 200 220 221 224 227 237 240 247 248 249 268 275 280 282 286 292 315 316 335 337 344 348 350 351 362 370 374 375 378 380 392 393 394 395 396 404 405 407 409 PRESSURE CONTROL, 159 166 167 192 275 286 PRESSURE DEPENDENCE, 22 31 129 137 201 202 252 316 337 385 PRESSURE DROP, 41 201 202 PRESSURE-SENSITIVE ADHESIVE, 43 68 PRESSURISATION, 275 278 PROCESS CAPABILITY, 31 32 376 PROCESSABILITY, 6 26 62 79 94 203 347 PROCESSING, 2 4 19 31 39 47 48

62 79 97 99 104 112 115 116 127 143 165 178 182 195 198 200 201 208 209 218 223 270 271 320 329 333 353 356 373 376 395 403 407 PROOFED FABRIC, 243 PROPANE, 88 149 170 314 331 336 345 393 405 411 PROPYLENE COPOLYMER, 10 98 116 355 PROPYLENE-ETHYLENE COPOLYMER, 26 PROTEIN, 99 193 370 PULSED LASER POLYMERISATION, 136 328 PURIFICATION, 79 218 270 373 392 409 PYROLYSIS, 102 162 320

R RADICAL POLYMERISATION, 5 7 9 49 55 59 61 67 89 122 130 131 145 146 190 191 222 223 257 263 276 299 328 353 RATE CONSTANT, 51 136 175 197 RATE OF POLYMERISATION, 9 21 75 122 177 222 REACTION CONDITIONS, 17 18 61 89 92 98 111 128 138 197 213 248 376 REACTION INJECTION MOULDING, 204 410 REACTION MECHANISM, 17 18 35 84 92 197 248 293 REACTION PRESSURE, 111 173 248 376 REACTION RATE, 21 197 248 REACTION TEMPERATURE, 17 174 248 376 REACTION TIME, 111 138 174 248 REACTIVE EXTRUSION, 11 98 REACTOR, 3 89 122 197 376 391 RECIPROCATING SCREW, 178 RECLAIM, 109 294 302 318 363 364 381 RECLAIMING, 45 119 165 189 277 349 396 402 406 RECLAMATION, 189 277 402 RECYCLING, 12 18 38 52 56 73 74 79 88 102 109 160 161 171 172 189 195 197 226 248 250 259 271 277 292 294 302 318 320 332 334 343 349 362 363 364 368 371 373 381 402 410 REINFORCED PLASTIC, 30 31

© Copyright 2004 Rapra Technology Limited

Subject Index

40 64 65 69 76 78 102 172 187 260 333 349 369 386 402 RHEOLOGICAL PROPERTIES, 2 6 10 26 30 48 54 72 78 79 80 87 88 94 98 101 105 113 114 116 123 127 141 142 166 167 186 191 192 193 201 202 206 215 217 221 242 250 251 262 278 282 284 285 305 333 340 342 357 361 RIBONUCLEASE, 99 210 RING-OPENING POLYMERISATION, 16 18 27 128 174 207 299 355 387 415 RUBBER, 2 28 44 45 68 82 90 92 115 119 130 137 165 166 187 192 199 203 205 216 225 237 294 313 321 323 324 325 326 327 330 331 332 334 344 351 353 355 360 361 366 367 371 372 377 378 380 385 387 388 392 397 401 408 409 410 414

S SATURATED POLYESTER, 179 200 208 209 210 220 221 268 279 320 375 SCANNING ELECTRON MICROSCOPY, 4 15 19 23 27 29 39 40 46 48 49 55 57 59 69 77 83 87 93 97 106 111 116 121 127 130 134 150 155 157 170 173 181 183 184 186 194 195 213 232 233 239 246 255 267 274 294 296 331 333 338 350 359 377 383 384 390 413 SCRAP TYRES, 2 294 362 SCREW DESIGN, 196 SCREW EXTRUDER, 26 123 204 217 242 SCREW PLASTICISATION, 166 SEEDED POLYMERISATION, 270 SEMI-CONTINUOUS POLYMERISATION, 401 SEMICRYSTALLINE, 90 91 127 149 183 244 336 384 SEPARATION, 36 56 259 279 292 367 372 381 402 406 SEQUENTIAL INJECTION MOULDING, 166 SHEAR FLOW, 105 202 SHEAR PROPERTIES, 105 215 361 SHEAR RATE, 6 72 105 127 141 142 282 305 348 361 SHOT SIZE, 4 97 129

SILICONE COPOLYMER, 291 SILICONE ELASTOMER, 130 216 408 SILICONE POLYMER, 7 28 88 96 115 216 226 335 SIMULATION, 8 17 197 276 388 SINGLE SCREW EXTRUDER, 26 204 242 339 357 SIZE EXCLUSION CHROMATOGRAPHY, 52 84 136 146 190 232 256 314 327 SKIN FORMATION, 394 395 SKIN-CORE, 29 SKIN-INSERT MOULDING, 167 SLIT DIE, 72 201 202 339 SLIT-DIE RHEOMETER, 215 SLOT DIE, 72 201 202 339 SLURRY POLYMERISATION, 376 391 SMALL ANGLE NEUTRON SCATTERING, 156 182 SOLID STATE POLYMERISATION, 75 231 273 281 SOLUBILITY, 3 8 44 48 51 52 57 62 70 88 90 92 95 100 113 114 127 128 137 148 150 167 169 173 176 179 180 187 191 193 194 216 218 221 223 231 234 240 244 251 258 260 280 291 297 304 306 309 335 336 342 343 357 374 375 404 405 414 SOLUBILITY PARAMETER, 88 335 354 388 SOLUTION, 99 108 113 132 137 182 192 193 219 292 331 333 345 378 380 395 405 SOLUTION POLYMERISATION, 21 88 125 136 148 190 218 308 309 336 353 355 SOLVATION, 8 88 176 218 SOLVENT EMISSION, 403 407 SOLVENT EVAPORATION, 380 SOLVENT EXTRACTION, 56 193 370 409 SOLVENT-FREE, 214 236 407 SORPTION, 14 55 61 117 132 158 182 218 220 242 388 414 SPECTRA, 5 34 35 111 SPECTROSCOPY, 1 2 3 5 10 23 34 35 37 55 59 92 93 98 125 132 160 174 182 213 214 235 248 337 339 341 SPHERE, 27 193 225 345 SPINNING, 87 200 230 247 SPRAY COATING, 403 407 SPRAYING, 384 407 416 STABILISER, 7 28 60 67 86 111

© Copyright 2004 Rapra Technology Limited

147 157 213 239 255 257 267 288 289 291 297 304 307 354 STATIC MIXER, 204 260 STEP-GROWTH POLYMERISATION, 353 STEREOREGULARITY, 126 355 STIRRED TANK REACTOR, 89 STIRRING, 122 135 222 STRUCTURAL FOAM, 203 STYRENE, 61 172 205 STYRENE ACRYLONITRILE COPOLYMER, 88 249 STYRENE-BUTADIENESTYRENE BLOCK COPOLYMER, 90 STYRENE COPOLYMER, 168 257 267 355 380 398 415 STYRENE-MALEIC ANHYDRIDE TERPOLYMER, 228 260 SUBCRITICAL, 110 293 SUBCRITICAL FLUID, 38 162 174 175 385 SUBLIMATION, 88 315 SUGAR COPOLYMER, 223 SUPERCONDENSING MODE, 336 355 391 SUPERCRITICAL SOLUTION, 26 31 32 62 73 78 105 137 154 189 192 193 196 225 331 356 398 SUPERCRITICAL SOLVENT, 8 72 88 125 137 177 193 201 202 207 235 265 281 291 331 349 358 371 377 SURFACE ACTIVE AGENT, 15 49 57 88 96 106 150 173 193 211 236 288 304 321 352 SURFACE FINISH, 12 42 166 167 192 262 286 SURFACE PROPERTIES, 23 46 77 92 93 177 195 359 413 SURFACE TENSION, 180 335 395 SURFACE TREATMENT, 25 63 92 236 316 359 403 SURFACTANT, 15 49 57 88 96 106 150 173 193 211 236 266 278 288 304 SURFACTANT FREE, 135 148 222 SURGICAL APPLICATION, 210 263 SUSPENSION, 106 193 211 278 SUSPENSION POLYMERISATION, 57 88 100 184 336 355 SWELLING, 2 10 45 66 90 91 92 107 119 130 132 140 147 149 152 170 186 193 200 214 219 249 296 313 337 361 395 408

133

Subject Index

414 SWELLING AGENT, 55 61 130 131 193 224 SYNDIOSPECIFIC POLYMERISATION, 355 SYNDIOTACTIC, 36 283 336 355 358 SYNTHESIS, 7 9 10 36 49 60 67 68 75 93 96 107 122 126 141 147 148 155 168 175 182 184 191 198 211 219 222 246 263 264 266 270 272 278 279 300 350 353 354 358 369 383 395 400 401 411 415

T TACTICITY, 126 355 TANDEM EXTRUDER, 242 TELEPHONE, 166 TELEVISION, 166 286 TEMPERATURE CONTROL, 159 167 204 260 TEMPERATURE DEPENDENCE, 6 17 22 26 104 110 129 137 201 238 252 291 316 328 378 405 TENSILE PROPERTIES, 31 32 65 69 78 97 107 129 130 131 143 151 185 208 224 230 252 287 TEREPHTHALIC ACID, 279 TERPOLYMERISATION, 168 TETRAFLUOROETHANE, 141 282 372 TETRAFLUOROETHYLENE COPOLYMER, 46 124 148 377 TETRAFLUOROETHYLENEHEXAFLUOROPROPYLENE COPOLYMER, 143 377 TETRAHYDROFURAN, 54 128 TEXTILE, 243 399 THERMAL DEGRADATION, 45 109 163 164 238 293 295 296 356 THERMAL INSULATION, 83 THERMAL POLYMERISATION, 190 389 THERMAL PROPERTIES, 19 66 71 81 86 90 91 94 121 127 131 142 169 182 192 193 248 316 345 374 375 380 383 THERMOGRAVIMETRIC ANALYSIS, 53 117 125 158 375 THERMOPLASTIC ELASTOMER, 64 82 192 203 204 237 299 331 355 THICKNESS, 44 46 62 79 133 194 394 TOLUENE, 9 27 43 68 88 128 205

134

TOLUENE DIAMINE, 343 TRANSITION PHENOMENA, 6 30 94 217 228 TRANSMISSION ELECTRON MICROSCOPY, 4 15 19 23 29 54 55 69 76 83 93 106 107 116 130 150 155 170 173 181 183 184 232 233 251 274 294 296 359 TRIFLUOROCHLOROETHYLENE COPOLYMER, 148 TRIFLUOROMETHANE, 350 TRIMETHYLOL PROPANE, 263 TUBING, 143 151 TUBULAR REACTION, 336 TURBIDIMETRY, 147 246 255 TWIN-SCREW EXTRUDER, 2 79 199 217 242 274 284 285 333 373 TWO-MATERIAL INJECTION MOULDING, 29 166 TYRE, 2 294 362

U ULTRA HIGH MOLECULAR WEIGHT POLYETHYLENE, 50 71 104 208 230 ULTRADRAWN, 230 UNSATURATED POLYESTER, 138 172 407 UREA-FORMALDEHYDE RESIN, 407 UV POLYMERISATION, 121 UV SPECTROSCOPY, 81 92 93 194 212 214 307 337

V VAPOUR PHASE POLYMERISATION, 336 355 VEHICLE INTERIOR, 42 VEHICLE MIRROR, 167 286 VEHICLE TRIM, 64 VIBRATIONAL SPECTROSCOPY, 3 10 23 61 80 107 126 132 171 191 283 294 VINYL ACETATE COPOLYMER, 124 148 402 VINYL ESTER COPOLYMER, 358 VINYL PYRROLIDONE, 49 VINYL TRIFLUOROACETATE COPOLYMER, 358 VINYLIDENE FLUORIDE COPOLYMER, 46 81 91 148 240

VISCOELASTIC, 141 142 316 VISCOSITY, 2 6 26 48 54 72 78 79 84 87 88 98 101 105 113 114 123 141 142 166 167 186 191 192 193 201 202 206 215 221 242 250 251 262 278 282 284 285 305 333 340 342 357 378 VISCOSITY MODIFIER, 94 245 339 VISIBLE SPECTROSCOPY, 92 93 214 337 VOLATILE ORGANIC COMPOUND, 263 269 347 397 403 VULCANISATE, 45 119 237 331

W WALL THICKNESS, 166 167 192 237 WASHING MACHINE, 166 WASTE, 74 88 102 172 226 277 292 332 349 396 402 406 WATER, 13 37 38 88 108 132 134 160 161 162 163 164 166 171 175 189 205 211 223 226 259 264 293 315 320 332 336 349 WATER ABSORPTION, 121 151 WATER BLOWN, 24 WATER DEGRADABLE, 13 WATER SOLUBILITY, 181 343 WATER-ASSISTED INJECTION MOULDING, 166 WEIGHT REDUCTION, 41 42 166 167 179 192 203 237 286 404 WELD LINE, 31 97 129 166 WIDE ANGLE X-RAY SCATTERING, 47 71 183 WOOD, 115 269

X X-RAY SCATTERING, 19 23 47 53 54 61 69 71 76 80 183 212 219 XYLYLENE POLYMER, 73

Y YIELD, 20 37 67 148 163 164 171 174 175 197 213 317 320 350 377

Z ZIEGLER-NATTA CATALYST, 336 355 376

© Copyright 2004 Rapra Technology Limited

Company Index

Company Index A ACHILLES CORP., 24 AIR PRODUCTS & CHEMICALS, 304 335 AIR PRODUCTS POLYMERS GMBH & CO.KG, 291 AKRON,UNIVERSITY, 7 400 411 ALICANTE,UNIVERSITY, 195 ALUSUISSE COMPOSITES, 237 253 AMERICAN CHEMICAL SOCIETY, 369 AMHERST,MASSACHUSETTS UNIVERSITY, 71 232 296 ATOFINA CHEMICALS INC., 186 AUBURN,UNIVERSITY, 106 205 292 294 AUSTIN,UNIVERSITY OF TEXAS, 384 AXIOMATICS CORP., 404

B BARCELONA,INSTITUT DE CIENCIA DE MATERIALS, 193 BASF, 376 BEIJING,INSTITUTE OF CHEMISTRY, 95 107 224 BEIJING,STATE KEY LABORATORY OF ENGINEERING PLASTIC, 47 BEIJING,UNIVERSITY OF TECHNOLOGY & BUSINESS, 14 BRADFORD,UNIVERSITY, 324 BROOKLYN,POLYTECHNIC UNIVERSITY, 18 BRUNEL UNIVERSITY, 123 201 BUCKEYE TECHNOLOGIES, 279

C CAMBRIDGE,UNIVERSITY, 323 CANADA,NATIONAL RESEARCH COUNCIL, 21 CATALUNYA,UNIVERSITAT POLITECNICA, 88 CAVENDISH LABORATORY, 134 CHANGCHUN,INSTITUTE OF APPLIED CHEMISTRY, 34 35 80 138 CHEMICAL & POLYMER, 115 236 269 344

CHIBA,INSTITUTE OF TECHNOLOGY, 37 248 CHINESE ACADEMY OF SCIENCES, 17 61 130 131 171 CHINESE CULTURE UNIVERSITY, 108 CINCINNATI,UNIVERSITY, 345 CLAUSTHAL,TECHNICAL UNIVERSITY, 8 CLEMSON,UNIVERSITY, 356 CNRS, 190 256 CONNECTICUT,UNIVERSITY, 1 187 COPENHAGEN,UNIVERSITY, 152 219 CORNELL UNIVERSITY, 180

D DELAWARE,UNIVERSITY, 313 380 398 405 DEMAG ERGOTECH GMBH, 42 DEUTSCHES DEXTILFORSCHUNGSZENTRUM NORD-WEST EV, 315 316 346 399 DOW, 376 388 DSM HIGH PERFORMANCE FIBERS, 230 DSM RESEARCH, 84 DU PONT DE NEMOURS E.I.,& CO.INC., 377 DUMAPLAST, 237 DUPONT CO., 151 153 DUPONT FLUOROPOLYMERS, 143

F FARADAY PLASTICS, 188 FENG CHIA,UNIVERSITY, 212 FERRO CORP., 169 322 FRAUNHOFER-INSTITUT FUER CHEMISCHE TECHNOLOGIE, 56 246 363 364 FUKUI,UNIVERSITY, 36 176 FUKUOKA,UNIVERSITY, 70 173

G GEORGIA,INSTITUTE OF TECHNOLOGY, 58 92 214 279 337 341 GERMAN TEXTILE RESEARCH INSTITUTE NORTH-WEST EV, 209 GOTTINGEN,GEORG-AUGUSTUNIVERSITAT, 8 9 136 168 GOTTINGEN,UNIVERSITY, 146 GUNMA,UNIVERSITY, 271

H HANYANG,UNIVERSITY, 197 HARBIN,INSTITUTE OF TECHNOLOGY, 37 248 HITACHI CABLE LTD., 160 HOECHST, 376 HOECHST CELANESE CORP., 367 396 HUSKY INJECTION MOULDING SYSTEMS LTD., 192

E

I

ECLIPSE BLIND SYSTEMS INC., 237 253 EINDHOVEN,UNIVERSITY OF TECHNOLOGY, 5 74 84 139 230 328 ENGEL NORTH AMERICA, 167 229 EPSRC, 371 ETABLISSEMENTS VALOIS, 392 EXPRESS SEPARATIONS LTD., 327 EXXON, 376 EXXON RESEARCH & ENGINEERING CO., 309 331

I-SHOU,UNIVERSITY, 221 ICI CHEMICALS & POLYMERS LTD., 409 INDIAN INSTITUTE OF SCIENCE, 110 238 INSTITUTO DE CIENCIA Y TECNOLOGIA DE POLIMEROS, 193

© Copyright 2005 Rapra Technology Limited

J JAPAN,CHEMICAL INNOVATION INSTITUTE, 158 159 JAPAN,NATIONAL INSTITUTE

135

Company Index

OF ADVANCED INDUSTRIAL SCIENCE & TECHNOL, 160 162 172 175 177 JAPAN,NATIONAL INSTITUTE OF MATERIALS & CHEMICAL RESEARCH, 265 368 JAPAN,SOCIETY OF PLASTICS RECYCLING, 102 JILIN,UNIVERSITY, 34 35 80 83 138 JOHN HOPKINS UNIVERSITY, 240 244 306 393 JOHNSON S.C.,& SON INC., 415 JSR CORP., 267 289 JYCO SEALING TECHNOLOGIES, 82

K KARLSRUHE,UNIVERSITY, 147 246 KAYSUN CORP., 32 129 KENAN LABORATORIES, 389 KIEL,CHRISTIAN-ALBRECHTUNIVERSITY, 258 370 KOBE SEIKO SHO KK, 259 KOBE STEEL LTD., 332 343 KOBE,UNIVERSITY, 28 54 157 KONOSHIMA CHEMICAL CO.LTD., 173 KOREA,INSTITUTE OF SCIENCE & TECHNOLOGY, 16 27 240 KOSA, 279 KUMAMOTO,INDUSTRIAL RESEARCH INSTITUTE, 172 174 KUMAMOTO,UNIVERSITY, 174 KUMOH,NATIONAL UNIVERSITY OF TECHNOLOGY, 137 KYOTO,INSTITUTE OF TECHNOLOGY, 45 70 119 200 247 KYOTO,MUNICIPAL TEXTILE RESEARCH INSTITUTE, 200 KYOTO,UNIVERSITY, 45 113 116 119 165

L LAUSANNE,ECOLE POLYTECHNIQUE FEDERALE, 250 LAWRENCE LIVERMORE NATIONAL LABORATORY, 413

136

LEHIGH UNIVERSITY, 331 LIEGE,UNIVERSITY, 207 LIFESTYLE & ENVIRONMENTAL TECHNOLOGY LABORATORIES, 161 LIQUID CARBONIC INC., 373 LIVERPOOL,UNIVERSITY, 63 77 134 184 198 263 270 LONDON,IMPERIAL COLLEGE OF SCIENCE,TECHNOLOGY & MEDICINE, 132 206 245 283 366 385 414 LOS ALAMOS NATIONAL LABORATORY, 374 375 LOUISIANA,STATE UNIVERSITY, 331 LOWELL,UNIVERSITY, 374 375

M MADISON GROUP, 4 MAINE,UNIVERSITY, 302 378 MAR DEL PLATA,UNIVERSIDAD NACIONAL, 195 MARIBOR,UNIVERSITY, 227 MASSACHUSETTS,INSTITUTE OF TECHNOLOGY, 180 404 MASSACHUSETTS,UNIVERSIT Y, 26 33 65 78 104 149 170 182 183 185 208 252 276 319 338 345 382 MASSACHUSETTSAMHERST,UNIVERSITY, 287 MAX-PLANCK-INSTITUT FUER KOHLENFORSCHUNG, 177 MAX-PLANCK-INSTITUT FUER POLYMERFORSCHUNG, 257 MCP EQUIPMENT LTD., 188 MELVILLE LABORATORY, 288 MENDELEEV UNIVERSITY OF CHEMICAL TECHNOLOGY, 3 MICELL TECHNOLOGIES, 46 51 243 MINNESOTA MINING & MFG. CO., 321 358 372 MINNESOTA,UNIVERSITY, 137 MITSUBISHI GAS CHEMICAL CO.INC., 70 MITSUBISHI PETROCHEMICAL, 376 MITSUI CHEMICALS INC., 275 MITSUI TOATSU CHEMICALS INC., 348 MOSCOW,INSTITUTE OF ORGANIC CHEMISTRY, 20 MOSCOW,INSTITUTE OF

ORGANOELEMENT COMPOUNDS, 20 MOSCOW,LOMONOSOV UNIVERSITY, 152

N NESMEYANOV INSTITUTE OF ORGANO-ELEMENT COMPOUNDS, 219 NESTE OY, 376 NEW JERSEY,INSTITUTE OF TECHNOLOGY, 194 NIIGATA,UNIVERSITY, 109 NIPPON TELEGRAPH & TELEPHONE CORP., 161 NISHIKAWA RUBBER CO., 334 NITTO DENKO CORP., 43 68 NORDSON CORP., 407 NORTH CAROLINA,CHAPEL HILL UNIVERSITY, 89 145 231 233 289 330 NORTH CAROLINA,STATE UNIVERSITY, 51 62 75 79 89 122 127 135 142 145 154 155 156 179 181 186 215 222 231 233 254 266 NORTH CAROLINA,UNIVERSITY, 53 62 122 142 150 154 155 181 223 241 264 267 273 281 297 298 299 300 304 307 310 328 347 353 354 369 377 387 389 390 NORTH TEXAS,UNIVERSITY, 19 22 NORTHEASTERN UNIVERSITY, 93 NOTTINGHAM,UNIVERSITY, 15 18 40 50 57 60 67 86 99 111 112 210 213 235 239 255 263 325 NOVA CHEMICALS (INTERNATIONAL) SA, 351 NOVACOR, 376 NOVASEP, 326

O OHIO,STATE UNIVERSITY, 30 48 59 69 114 133 199 217 251 274 284 339 342 OSAKA,UNIVERSITY, 379 OSI SPECIALITIES INC., 397

P PACIFIC NORTHWEST NATIONAL LABORATORY, 46

© Copyright 2005 Rapra Technology Limited

Company Index

PALERMO,UNIVERSITY, 10 49 96 PENNSYLVANIA,STATE UNIVERSITY, 280 PHASEX CORP., 234 290 314 393 PITTSBURGH,UNIVERSITY, 303 309 352 381 383 394 395 402 406 408 POLYMER PROCESSING INSTITUTE, 237 PROCTER & GAMBLE CO., 380 PUSAN,NATIONAL UNIVERSITY, 176

R RADFORD,UNIVERSITY, 359 RAPRA TECHNOLOGY LTD., 188 204 228 237 260 REEDY INTERNATIONAL CORP., 118 262 REPSOL SA, 336 ROHM & HAAS CO., 311 401 ROSKILDE,UNIVERSITY, 3 20 ROSTI MEDICAL PLASTICS, 25 RUSSIAN ACADEMY OF SCIENCES, 3 40 152 191

S SAN JUAN,NATIONAL UNIVERSITY, 195 SCHERING CORP., 360 SEOUL,NATIONAL UNIVERSITY, 16 27 SHANGHAI,DONGHUA UNIVERSITY, 23 120 126 SHIZUOKA,UNIVERSITY, 160 162 172 SIEGEN,UNIVERSITAT, 52 410 SLOVAK ACADEMY OF SCIENCES, 146 SMITH & NEPHEW, 57 SOUTH ALABAMA,UNIVERSITY, 362 SOUTHWEST TEXAS,STATE UNIVERSITY, 125 128 272 SRI INTERNATIONAL, 376 SULZER CHEMTECH AG, 42 SUMITOMO BAKELITE CO.LTD., 295 SURREY,UNIVERSITY, 115 239 269 344 371 SUSSEX,UNIVERSITY, 67 350

T TAIPEI,NATIONAL TAIWAN UNIVERSITY, 108 TAIWAN,NATIONAL UNIVERSITY OF SCIENCE & TECHNOLOGY, 101 105 TAKEDA CHEMICAL INDUSTRIES LTD., 259 343 TEXAS A & M UNIVERSITY, 308 TEXAS,UNIVERSITY, 100 211 255 278 335 TEXAS,UNIVERSITY AT AUSTIN, 304 TIANJIN,UNIVERSITY, 13 TOHOKU ELECTRIC POWER CO.INC., 163 261 TOHOKU,UNIVERSITY, 163 164 261 320 TOKYO,INSTITUTE OF TECHNOLOGY, 200 TONGJI,UNIVERSITY, 87 126 TORINO,POLITECNICO, 220 TORONTO,UNIVERSITY, 124 148 237 242 268 285 333 357 TOYO TIRE & RUBBER CO.LTD., 45 165 TOYOTA CENTRAL R & D LABORATORIES INC., 116 TOYOTA TECHNOLOGICAL INSTITUTE, 76 116 TREXEL, 42 64 82 144 166 167 178 192 196 203 229 237 253 TRIESTE,UNIVERSITY, 85 TSINGHUA,UNIVERSITY, 121 TSUKUBA,NATIONAL INSTITUTE OF MATERIALS & CHEMICAL RESEARCH, 277

U UK,HEALTH AND SAFETY LABORATORY, 86 UNICARB SYSTEM EUROPE, 407 UNILEVER RESEARCH, 301 335 UNION CARBIDE, 376 UNION CARBIDE CHEMICALS & PLASTICS CO.INC., 407 416 UNION CARBIDE CORP., 403 UNIQEMA, 67 111 213 UNITIKA LTD., 76 US,ARMY, 231 US,ARMY RESEARCH OFFICE, 75 281 US,ARMY SOLDIER SYSTEMS

© Copyright 2005 Rapra Technology Limited

COMMAND, 71 104 US,ARMY,ABERDEEN PROVING GROUND, 117 US,CENTER FOR COMPOSITE MATERIALS, 386 US,DEPT.OF AGRICULTURE,FOREST PRODUCTS LABORATORY, 32 US,DEPT.OF ENERGY, 412 US,NASA,LANGLEY RESEARCH CENTER, 359 US,RESEARCH & TECHNOLOGY DIRECTORATE, 117

V VIRGINIA,COMMONWEALTH UNIVERSITY, 66 81 90 91 137 140 156 169 216 225 240 VIRGINIA,POLYTECHNIC INSTITUTE & STATE UNIVERSITY, 6 94 365

W WACKER POLYMER SYSTEMS GMBH & CO.KG, 291 WARWICK,UNIVERSITY, 41 WASHINGTON,UNIVERSITY, 39 WATERLOO,UNIVERSITY, 2 11 44 72 98 103 202 242 285 314 333 357 WAYNE STATE,UNIVERSITY, 141 282 305 340 361 WISCONSINMADISON,UNIVERSITY, 4 29 31 32 97 129 388

X XEROX CORP., 312

Y YAMAGATA,UNIVERSITY, 38 73 293 295 317 318 YAZAKI CORP., 226 YONSEI,UNIVERSITY, 249

Z ZENECA AGROCHEMICALS, 288 ZHENGZHOU,UNIVERSITY, 55 61

137

Company Index

138

© Copyright 2005 Rapra Technology Limited

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