PLASTICS MATERIALS SEVENTH EDITION J. A. Brydson Former Head of the Department of Physical Sciences and Technology, Polytechnic of North London (now known as the University of North London) f EINEMANN OXFORD AUCKLAND BOSTON JOHANNESBURG MELBOURNE NEW DELHI Butterworth-Heinemann Linacre House, Jordan Hill, Oxford OX2 8DP 225 Wildwood Avenue, Wobum, MA 01801-2041 A division of Reed Educational and Professional Publishing Ltd A member of the Reed Elsevier plc group First published by Iliffe Books Ltd 1966 Second edition 1969 Reprinted 1970 Third edition 1975 Reprinted with revisions 1977 Reprinted 1979 Fourth edition published by Butterworth-Heinemann 1982 Reprinted 1985 Fifth edition 1989 Reprinted 1991, 1993 Sixth edition 1995 Reprinted 1995, 1996, 1998 Seventh edition 1999 0 J. A. Brydson 1995, 1999 All rights reserved. No part of this publication may be reproduced in any material form (including photocopying or storing in any medium by electronic means and whether or not transiently or incidentally to some other use of this publication) without the written permission of the copyright holder except in accordance with the provisions of the Copyright Designs and Patents Act 1988 or under the terms of a licence issued by the Copyright Licensing Agency Ltd, 90 Tottenham Court Road, London, England WlP 9HE. Applications for the copyright holder’s written permission to reproduce any part of this publication should be addressed to the publisher British Library Cataloguing in Publication Data Brydson, J. A. (John Andrew), 1932- Plastics materials. - 7th ed. 1. Plastics I. Title 668.4 ISBN 0 7506 4132 0 Library of Congress Cataloguing in Publication Data Brydson, J. A. Plastics materia1slJ.A. Brydson. - 7th ed. p. cm. Includes bibliographical references and index. ISBN 0 7506 4132 0 (hbk.) 1. Plastics. I. Title. TP1120 B7 99-30623 668.4-dc21 CIP Composition by Genesis Typesetting, Laser Quay, Rochester, Kent Printed and bound in Great Britain by Biddles Lt4 Guildford and King’s Lynn Contents Preface to the Seventh Edition Preface to the First Edition Acknowledgements for the Seventh Edition Abbreviations for Plastics and Rubbers 1 The Historical Development of Plastics Materials 1.1 Natural Plastics 1.2 Parkesine and Celluloid 1.4 1.5 Developments since 1939 1.6 Raw Materials for Plastics 1.7 The Market for Plastics 1.8 The Future for Plastics 1.3 1900-1930 The Evolution of the Vinyl Plastics 2 The Chemical Nature of Plastics 2.1 Introduction 2.2 Thermoplastic and Thermosetting Behaviour 2.3 Further Consideration of Addition Polymerisation 2.3.1 2.3.2 Ionic polymerisation 2.3.3 Ziegler-Natta and metallocene polymerisation Elementary kinetics of free-radical addition polymerisation 2.4 Condensation Polymerisation 3 States of Aggregation in Polymers 3.1 Introduction 3.2 Linear Amorphous Polymers 3.2.1 3.3 Crystalline Polymers 3.3.1 Orientation and crystallisation 3.3.2 Liquid crystal polymers Orientation in linear amorphous polymers 3.4 Cross-linked Structures 3.5 Polyblends 3.6 Summary xvii xix xxi xxiii 1 1 3 4 6 7 9 11 15 19 19 23 24 29 33 37 39 43 43 43 47 49 52 53 53 55 57 V vi Contents 4 Relation of Structure to Thermal and Mechanical Properties 4.1 Introduction 4.2 Factors Affecting the Glass Transition Temperature 4.3 Factors Affecting the Ability to Crystallise 4.4 Factors Affecting the Crystalline Melting Point 4.5 Some Individual Properties 4.5.1 Melt viscosity 4.5.2 Yield strength and modulus 4.5.3 Density 4.5.4 Impact strength 5 Relation of Structure to Chemical Properties 5.1 Introduction 5.2 Chemical Bonds 5.3 Polymer Solubility 5.3.1 Plasticisers 5.3.2 Extenders 5.3.3 Determination of solubility parameter 5.3.4 Thermodynamics and solubility Effects of Thermal, Photochemical and High-energy Radiation 5.4 Chemical Reactivity 5.5 5.6 Aging and Weathering 5.7 Diffusion and Permeability 5.8 Toxicity 5.9 Fire and Plastics 6 Relation of Structure to Electrical and Optical Properties 6.1 Introduction 6.2 6.3 6.4 Electronic Applications of Polymers 6.5 Electrically Conductive Polymers 6.6 Optical Properties Appendix-Electrical Testing Dielectric Constant, Power Factor and Structure Some Quantitative Relationships of Dielectrics 7 Additives for Plastics 7.1 Introduction 7.2 Fillers 7.2.1 Coupling agents 7.3 Plasticisers and Softeners 7.4 Lubricants and Flow Promoters 7.5 Anti-aging Additives 7.5.1 Antioxidants 7.5.2 Antiozonants 7.5.3 Stabilisers against dehydrochlorination 7.5.4 Ultraviolet absorbers and related materials 7.6 Flame Retarders 7.7 Colorants 7.8 Blowing Agents 7.9 Cross-linking Agents 7.10 Photodegradants 7.11 2-Oxazolines 59 59 59 64 70 73 73 74 74 74 76 76 76 80 87 89 89 93 95 96 99 100 103 1 04 110 110 110 117 119 120 120 122 124 124 126 128 131 132 134 134 143 143 143 145 149 150 153 154 155 Contents vii 8 Principles of the Processing of Plastics 8.1 Introduction 8.2 Melt Processing of Thermoplastics 8.2.1 Hygroscopic behaviour 8.2.2 Granule characteristics 8.2.3 8.2.4 Thermal stability 8.2.5 Flow properties 8.2.5.1 Terminology 8.2.5.2 Effect of environmental and molecular factors on viscous flow properties 8.2.5.3 Flow in an injection mould 8.2.5.4 Elastic effects in polymer melts 8.2.6 Thermal properties affecting cooling 8.2.7 Crystallisation 8.2.8 Orientation and shrinkage Melt Processing of Thermosetting Plastics Processing in the Rubbery State Solution, Suspension and Casting Processes Thermal properties influencing polymer melting 8.3 8.4 8.5 8.6 Summary 9 Principles of Product Design 9.1 Introduction 9.2 Rigidity of Plastics Materials 9.2.1 The assessment of maximum service temperature 9.2.1.1 Assessment of thermal stability 9.2.1.2 Assessment of softening point The assessment of impact strength 9.3 Toughness 9.3.1 9.4 Stress-Strain-Time Behaviour 9.4.1 The WLF equations 9.4.2 Creep curves 9.4.3 9.5 Recovery from Deformation 9.6 Distortion, Voids and Frozen-in Stress 9.7 Conclusions Practical assessment of long-term behaviour 10 Polyethylene 10.1 Introduction 10.2 Preparation of Monomer 10.3 Polymerisation 10.3.1 High-pressure polymerisation 10.3.2 Ziegler processes 10.3.3 The Phillips process 10.3.4 Standard Oil Company (Indiana) process 10.3.5 Processes for making linear low-density polyethylene and metallocene polyethylene Structure and Properties of Polyethylene 10.5.1 Mechanical properties 10.5.2 Thermal properties 10.5.3 Chemical properties 10.5.4 Electrical properties 10.5.5 10.5.6 Properties of metallocene-catalysed polyethylenes 10.4 10.5 Properties of Polyethylene Properties of LLDPE and VLDPE 158 158 159 159 159 161 163 163 164 167 170 171 174 17.5 175 176 179 181 182 184 184 184 186 186 188 190 192 195 196 198 200 20 1 202 204 205 205 207 208 208 209 210 211 21 1 212 217 217 22 1 223 226 227 227 viii Contents 10.6 Additives 10.7 Processing 10.8 10.9 Cross-linked Polyethylene 10.10 Chlorinated Polyethylene 10.11 Applications Polyethylenes of Low and High Molecular Weight 11 Aliphatic Polyolefins other than Polyethylene, and Diene Rubbers 11.1 Polypropylene 11.1.1 Preparation of polypropylene 11.1.2 11.1.3 Properties of isotactic polypropylene 11.1.4 Additives for isotactic polypropylene 11.1.5 Processing characteristics 11.1.6 Applications 11.1.7 Atactic and syndiotactic polypropylene 11.1.8 Chlorinated polypropylene 11.2.1 Atactic polybut- 1-ene Structure and properties of polypropylene 11.2 Polybut-1-ene 11.3 Polyisobutylene 11.4 Poly-(4-methylpent-l-ene) 11.4.1 Structure and properties 11.4.2 General properties 11.4.3 Processing 11.4.4 Applications 11.5 Other Aliphatic Olefin Homopolymers 11.6 Copolymers Containing Ethylene 1 1.6.1 1 1.6.2 Ethylene-cyclo-olefin copolymers 11.7 Diene Rubbers Ethylene-carbon monoxide copolymers (ECO) 11.7.1 Natural rubber 11.7.2 Synthetic polyisoprene (IR) 11.7.3 Polybutadiene 11.7.4 Styrene-butadiene rubber(SBR) 11.7.4.1 ‘High styrene resins’ 11.7.5 Nitrile rubber (NBR) 11.7.6 Chloroprene rubbers (CR) 11.7.7 Butadiene-pentadiene rubbers 11.8 Thermoplastic Diene Rubbers 11.9 Aliphatic Olefin Rubbers 11.10 Rubbery Cyclo-olefin (Cyclo-alkene) Polymers 11.9.1 Thermoplastic polyolefin rubbers 1 1.10.1 Aliphatic polyalkenamers 11.10.2 Polynorbomene 11.10.3 Chlorine-containing copolymers 11.11 1,2-Polybutadiene 11 .I2 Ethylene-styrene copolymers 11.13 Other elastomers 12 Vinyl Chloride Polymers 12.1 Introduction 12.2 Preparation of Vinyl Chloride 12.3 Polymerisation 12.4 Structure of Poly(viny1 chloride) 12.4.1 Characterisation of commercial polymers 228 232 238 239 240 24 1 247 247 248 25 1 253 260 262 265 267 268 268 269 269 270 270 272 273 273 273 275 278 280 280 285 289 290 29 1 294 294 295 296 296 299 302 304 304 306 307 307 308 309 311 311 313 315 317 320 12.5 12.6 12.7 12.8 12.9 Compounding Ingredients 12.5.1 Stabilisers 12.5.2 Plasticisers 12.5.3 Extenders 12.5.4 Lubricants 12.5.5 Fillers 12.5.6 Pigments 12.5.7 12.5.8 Miscellaneous additives 12.5.9 Formulations Properties of PVC Compounds Processing 12.7.1 Plasticised PVC 12.7.2 Unplasticised PVC 12.7.3 Pastes 12.7.4 Copolymers 12.7.5 Latices Applications Miscellaneous Products 12.9.1 Crystalline PVC 12.9.2 Chlorinated PVC 12.9.3 Graft polymers based on PVC 12.9.4 Vinyl chloride-propylene copolymers 12.9.5 Vinyl chloride-N-cyclohexylmaleimide copolymers Polymeric impact modifiers and processing aids 13 Fluorine-containing Polymers 13.1 Introduction 13.2 Polytetrafluoroethylene 13.2. I Preparation of monomer 13.2.2 Polymerisation 13.2.3 Structure and properties 13.2.4 General properties 13.2.5 Processing 13.2.6 Additives 13.2.7 Applications 13.3 Tetrafluoroethylene-Hexafluoropropylene Copolymers 1 3.4 Tetrafluoroethylene-Ethylene Copolymers (ETFE) 13.5 Polychlorotrifluoroethylene Polymers (PCTFE) 13.6 Poly(viny1 fluoride) (PVF) 13.7 Poly(viny1idene fluoride) 13.8 1 3.9 Hexafluoroisobutylene-Vinylidene Fluoride Copolymers 13.10 Fluorine-containing Rubbers 13.11 Thermoplastic fluoroelastomers 13.12 Miscellaneous Fluoropolymers Poly(viny1 acetate) and its Derivatives 14.1 Introduction 14.2 Poly(viny1 acetate) and Copolymers with Ethylene (ECTFE) Other Plastics Materials Containing Tetrafluoroethylene 14 14.2.1 Preparation of the monomer 1 4.2.2 Polymerisation 14.2.3 Properties and uses 14.3.1 Structure and properties 14.3.2 Applications 14.3 Poly(viny1 alcohol) Contents ix 325 325 330 336 336 337 338 338 342 342 345 346 347 349 350 354 355 355 359 359 359 360 360 360 363 363 364 364 364 365 361 369 37 1 372 373 374 374 376 376 377 379 379 383 384 386 386 386 386 388 389 389 390 39 1 x Contents 14.4 The Poly(viny1 acetals) 14.4.1 Poly(viny1 formal) 14.4.2 Poly(viny1 acetal) 14.4.3 Poly(viny1 butyral) 14.5 Ethylene-Vinyl Alcohol Copolymers 14.6 Poly(viny1 cinnamate) 14.7 Other Organic Vinyl Ester Polymers 15 Acrylic Plastics 15.i 15.2 15.3 15.4 15.5 15.6 15.7 15.8 15.9 15.10 15.11 Introduction Poly(methy1 methacrylate) 15.2.1 Preparation of monomer 15.2.2 Polymerisation 15.2.3 Structure and properties 15.2.4 15.2.5 Additives 15.2.6 Processing 15.2.7 Applications Methyl Methacrylate Polymers with Enhanced Impact Resistance and Softening Point Nitrile Resins Acrylate Rubbers Thermosetting Acrylic Polymers Acrylic Adhesives Hydrophilic Polymers Poly(methacry1imide) Miscellaneous Methacrylate and Chloroacrylate Polymers and Copolymers Other Acrylic Polymers General properties of poly(methy1 methacrylate) 16 Plastics Based on Styrene 16.1 16.2 16.3 16.4 16.5 16.6 16.7 16.8 16.9 16.10 16.11 16.12 16.13 Introduction Preparation of the Monomer 16.2.1 Laboratory preparation 16.2.2 Commercial preparation Polymerisation 16.3.1 Mass polymerisation 16.3.2 Solution polymerisation 16.3.3 Suspension polymerisation 16.3.4 Emulsion polymerisation 16.3.5 Grades available Properties and Structure of Polystyrene General Properties High-impact Polystyrenes (HIPS) (Toughened Polystyrenes (TPS)) Styrene-Acrylonitrile Copolymers ABS Plastics 16.8.1 Production of ABS materials 16.8.2 Processing of ABS materials 16.8.3 Miscellaneous Rubber-modified Styrene- Acrylonitrile and Related Copolymers Styrene-Maleic Anhydride Copolymers Butadiene-Styrene Block Copolymers Miscellaneous Polymers and Copolymers Stereoregular Polystyrene 16.13.1 Syndiotactic polystyrene Properties and applications of ABS plastics 39 1 392 393 393 394 395 397 398 398 400 400 40 1 405 405 409 409 41 I 413 415 417 418 419 420 420 42 1 423 425 425 426 426 427 429 429 43 1 43 1 432 432 433 434 437 44 1 441 442 447 447 448 450 450 452 454 454 Contents xi 16.14 Processing of Polystyrene 16.15 Expanded Polystyrene 16.15.1 Structural foams 16.16 Oriented Polystyrene 16.17 Applications 17 Miscellaneous Vinyl Thermoplastics 17.1 Introduction 17.2 Vinylidene Chloride Polymers and Copolymers 17.2.1 17.2.2 Vinylidene chloride-acrylonitrile copolymers Properties and applications of vinylidene chloride-vinyl chloride copolymers 17.3 Coumarone-Indene resins 17.4 Poly(viny1 carbazole) 17.5 Poly(viny1 pyrrolidone) 17.6 Poly(viny1 ethers) 17.7 Other Vinyl Polymers 18 Polyamides and Polyimides 18.1 18.2 18.3 18.4 18.5 18.6 18.7 18.8 18.9 18.10 18.1 1 18.12 18.13 18.14 18.15 18.16 Polyamides: Introduction Intermediates for Aliphatic Polyamides 18.2.1 Adipic acid 18.2.2 Hexamethylenediamine 18.2.3 18.2.4 Caprolactam 18.2.5 w-Aminoundecanoic acid 18.2.6 w-Aminoenanthic acid 18.2.7 Dodecanelactam Polymerisation of Aliphatic Polyamides 18.3.1 18.3.2 Nylon 6 18.3.3 Nylon 11 18.3.4 Nylon 12 18.3.5 Nylon 7 Structure and Properties of Aliphatic Polyamides General Properties of the Nylons Additives Glass-filled Nylons 18.7.1 Processing of the Nylons Applications Polyamides of Enhanced Solubility Other Aliphatic Polyamides Aromatic Polyamides 18.12.1 Glass-clear polyamides 18.12.2 Crystalline aromatic polyamides Sebacic acid and Azelaic acid Nylons 46, 66, 69, 610 and 612 Comparison of nylons 6 and 66 in glass-filled compositions 18.12.2.1 Poly-rn-xylylene adipamide 18.12.2.2 Aromatic polyamide fibres 18.12.2.3 Polyphthalamide plastics Polyimides Modified Polyimides 18.14.1 Polyamide-imides 18.14.2 Polyetherimides Elastomeric Polyamides 455 457 4.59 46 1 462 466 466 466 468 470 47 1 472 474 475 476 478 478 480 480 48 1 48 1 482 483 484 485 486 486 486 487 487 487 487 490 496 498 500 500 502 505 507 509 509 513 513 514 516 516 52 1 524 525 526 Polyesteramides- 528 xii Contents 19 Polyacetals and Related Materials 19.1 Introduction 19.2 Preparation of Formaldehyde 19.3 Acetal Resins 19.3.1 Polymerisation of formaldehyde 19.3.2 19.3.3 Properties of acetal resins 19.3.4 Processing 19.3.5 Additives 19.3.6 Acetal-polyurethane alloys 19.3.7 Polyethers from Glycols and Alkylene Oxides 19.5.1 Elastomeric polyethers Structure and properties of acetal resins Applications of the acetal polymers and copolymers 19.4 Miscellaneous Aldehyde Polymers 19.5 19.6 Oxetane Polymers 19.7 Polysulphides 20.1 Introduction 20.2 Production of Intermediates 20.3 Polymer Preparation 20 Polycarbonates 20.3.1 Ester exchange 20.3.2 Phosgenation process Relation of Structure and Properties 20.4.1 Variations in commercial grades 20.4 20.5 General Properties 20.6 Processing Characteristics 20.7 20.8 20.9 20.10 Miscellaneous Carbonic Ester Polymers Other Thermoplastics Containing p-Phenylene Groups Applications of Bis-phenol A Polycarbonates Alloys based on Bis-phenol A Polycarbonates Polyester Carbonates and Block Copolymers 2 1 21.1 21.2 21.3 21.4 21.5 21.6 21.7 21.8 21.9 21.10 Introduction Polyphenylenes Pol y-p-xylylene Poly(pheny1ene oxides) and Halogenated Derivatives Alkyl Substituted Poly(pheny1ene oxides) including PPO 21.5.1 Structure and properties of 21.5.2 21.5.3 21.5.4 Styrenic PPOs 21.5.5 Processing of styrenic PPOs 21.5.6 Polyamide PPOs 21 57 Poly(2,6-dibromo-l,4-phenylene oxide) Polyphenylene Sulphides 21.6.1 Amorphous polyarylene sulphides Pol ysulphones 21.7.1 21.7.2 General properties of polysulphones 21.7.3 Processing of polysulphones 21.7.4 Applications 21.7.5 Blends based on polysulphones Polyarylether Ketones Phenoxy Resins Linear Aromatic Polyesters poly-(2,6-dimethyl-p-phenylene oxide) (PPO) Processing and application of PPO Blends based in polyphenylene oxides Properties and structure of polysulphones 531 53 1 532 533 533 536 538 542 543 544 544 546 546 547 549 55 1 556 556 557 558 558 560 56 1 564 567 573 575 578 579 580 584 584 584 586 586 586 587 589 589 590 59 1 592 592 593 596 596 599 600 60 1 60 1 602 602 607 607 [...]...Contents xiii 21. 11 Polyhydantoin Resins 21. 12 Poly(parabanic acids) 21. 13 Summary 22 Cellulose Plastics 22 .1 Nature and Occurrence of Cellulose 22.2 Cellulose Esters 22.2 .1 Cellulose nitrate 22.2.2 Cellulose acetate 22.2.3 Other cellulose esters 22.3 Cellulose Ethers 22.3 .1 Ethyl cellulose 22.3.2 Miscellaneous ethers 22.4 Regenerated Cellulose 22.5 Vulcanised Fibre 609 610 611 613 613 616 616 62 1 627 629... Temperatures 29.7 29.7 .1 Fluorine-containing polymers 29.7.2 Inorganic polymers 29.7.3 Cross-linked organic polymers 29.7.4 Linear polymers with p-phenylene groups and other ring structures 29.7.5 Ladder polymers and spiro polymers 29.7.6 Co-ordination polymers 29.7.7 Summary xv 794 794 799 800 803 805 805 807 808 808 810 810 810 811 812 812 814 814 815 816 817 818 818 820 820 820 82 1 823 823 824 826 828... 30.7 .1 Composition and properties 30.8 Bituminous Plastics 853 853 853 854 855 856 858 859 860 860 865 867 867 868 868 869 870 870 87 1 3 1 Selected Functional Polymers 31 1 Introduction 3 1. 2 Thermoplastic Elastomers 3 1. 2 .1 Applications of thermoplastic elastomers 3 1. 2.2 The future for thermoplastic elastomers 3 1. 3 Degradable Plastics 31. 3 .1 Polyhydroxybutyrate-valerate copolymers (PHBV) 31. 3.2... Poly(trimethy1ene terephthalate) (PCT) 25.8 Poly-( 1, 4-~yclohexylenedimethyleneterephthalate) 25.8 .1 Poly-( 1, 4-~yclohexylenedimethyleneterephthalate25.9 25 .10 25 .11 25 .12 25 .13 co-isophthalate) Highly Aromatic Linear Polyesters 25.9 .1 Liquid crystal polyesters Polyester Thermoplastic Elastomers Poly(pivalo1actone) Polycaprolactones Surface Coatings, Plasticisers and Rubbers 26 Epoxide Resins 26 .1 Introduction... Abbreviations for Plastics and Rubbers Many abbreviations for plastics materials are in common use Some of these have now been incorporated into national and international standards, including: IS0 10 43 (19 78) Plastics- Symbols BS 3502 Common Names and Abbreviations for Plastics and Rubbers Part 1 Principal commercial plastics (19 78) (The 19 78 revision was carried out in accordance with IS 10 43 although... 839 840 84 1 84 1 842 846 847 848 850 85 1 xvi Contents 30 Miscellaneous Plastics Materials 30 .1 Introduction 30.2 Casein 30.2 .1 Chemical nature 30.2.2 Isolation of casein from milk 30.2.3 Production of casein plastics 30.2.4 Properties of casein 30.2.5 Applications 30.3 Miscellaneous Protein Plastics 30.4 Derivatives of Natural Rubber Gutta Percha and Related Materials 30.5 30.6 Shellac 30.6 .1 Occurrence... Pol y(propene) Poly(pheny1 ethene) Poly(ch1oroethene) Poly(methy1ene) Poly(propylene) Poly (1- phenyl ethylene) Poly( 1- chloroethylene) Poly(methy1 2-methyl propenoate) Poly[ 1- (methoxycarbonyl )1- methyl ethylene] In this book the policy has been to use normal usage scientific terms Table 3 Standard abbreviations for rubbery materials (based on I S 0 Recommendation and ASTM D 14 18) ABR ACM ACSM AECO AEM... Polyurethane-Acrylic Blends 27 .1 1 Miscellaneous Isocyanate-Based Materials 28 Furan 28 .1 28.2 28.3 28.4 28.5 29 Resins Introduction Preparation of Intermediates Resinification Properties of the Cured Resins Applications Silicones and Other Heat-resisting Polymers 29 .1 Introduction 29 .1. 1 Nomenclature 29 .1. 2 Nature of chemical bonds containing silicon 29.2 Preparation of Intermediates 29.2 .1 The Grignard method... compounding ingredients.) ASTM D 16 00-83 Abbreviations of terms relating to plastics DIN 7728 Part 1 (19 78) Symbols for terms relating to homopolymers, copolymers and polymer compounds Part 2 (19 80) Symbols for reinforced plastics In Table 1, drawn up by the author, of abbreviations in common use those in bold type are in the main schedule of BS 3502 In this list the names given for the materials are the commonly... Phenolic Laminates 23.6 .1 The properties of phenolic laminates 656 23.6.2 Applications of phenolic laminates 658 23.7 Miscellaneous Applications 659 23.8 Resorcinol-Formaldehyde Adhesives 662 662 23.9 Friedel-Crafts and Related Polymers 666 23 .10 Phenolic Resin Fibres 23 .11 Polybenzoxazines 666 24 Aminoplastics 668 668 24 .1 Introduction 669 24.2 Urea-Formaldehyde Resins 669 24.2 .1 Raw materials 24.2.2 Theories . 87 89 89 93 95 96 99 10 0 10 3 1 04 11 0 11 0 11 0 11 7 11 9 12 0 12 0 12 2 12 4 12 4 12 6 12 8 13 1 13 2 13 4 13 4 14 3 14 3 14 3 14 5 14 9 15 0 15 3 15 4 15 5 Contents vii 8 Principles. LLDPE and VLDPE 15 8 15 8 15 9 15 9 15 9 16 1 16 3 16 3 16 4 16 7 17 0 17 1 17 4 17 .5 17 5 17 6 17 9 18 1 18 2 18 4 18 4 18 4 18 6 18 6 18 8 19 0 19 2 19 5 19 6 19 8 200 20 1 202 204 205. 17 .5 Poly(viny1 pyrrolidone) 17 .6 Poly(viny1 ethers) 17 .7 Other Vinyl Polymers 18 Polyamides and Polyimides 18 .1 18 .2 18 .3 18 .4 18 .5 18 .6 18 .7 18 .8 18 .9 18 .10 18 .1 1 18 .12 18 .13