New Methods of Polymer Synthesis Volume 2 New Methods of Polymer Synthesis Volume 2 Edited by J. R. EBDON Director, The Polymer Centre University of Lancaster and G. C. EASTMOND Reader in Chemistry University of Liverpool SPRINGER-SCIENCE+BUSINESS MEDIA, B.V. First edition 1995 © 1995 Springer Science+Business Media Dordrecht Originally published by Chapman & Hali in 1995 Softcover reprint ofthe hardcover Ist edition 1995 Typeset in 1O/12pt Times by Pure Tech India Ltd., Pondicherry, India Bury St Edmunds, SufTolk ISBN 978-94-010-4268-0 ISBN 978-94-011-0607-8 (eBook) DOI 10.1007/978-94-011-0607-8 Apart from any fair dealing for the purposes of research or private study, or criticism or review, as permitted under the UK Copyright Designs and Patents Act, 1988, this publication may not be reproduced, stored, or transmitted, in any form or by any means, without the prior permission in writing of the publishers, or in the case of reprographic reproduction only in accordance with the terms of the licences issued by the Copyright Licensing Agency in the UK, or in accordance with the terms of licences issued by the appropriate Reproduction Rights Organization outside the UK. Enquiries concerning reproduction outside the terms stated here should be sent to the publishers at the Glasgow address printed on this page. The publisher makes no representation, express or implied, with regard to the accuracy of the information contained in this book and cannot accept any legal responsibility or liability for any errors or omissions that may be made. A catalogue record for this book is available from the British Library Library of Congress Catalog Card Number: 90-43657 t§Printed on acid-free text paper, manufactured in accordance with ANSI/NISO Z39.48-1992 (Permanence of Paper) Preface When New Methods of Polymer Synthesis was published in 1991, it was expected that a companion volume would eventually be warranted. However, such has been the pace of developments in polymer synthesis over the past four years that the need for another volume has come sooner than expected. Throughout the developed world, the requirement for polymers with special properties, and processes that offer better control over polymer structures, has continued unabated. The response to these demands has been remarkable, and has led to the establishment of new research groups in both academia and industry, many in centres that have not previously been noted for their polymer research, and involving a new generation of mainly organic chemists whose consider able synthetic skills have been brought to bear on the construction of new and modified macromolecules, with outstanding effect. Several such individuals are represented in the list of authors who have contributed to this volume. Also, the international nature of the current polymer synthetic endeavour can be seen in the list of the countries of origin of these contributions: Australia, France, Germany, Japan, the USA, and the UK. Like the first volume of New Methods of Polymer Synthesis, this second volume contains a set of essentially self-contained reviews, each of which covers a specific area of synthesis. Once again, the chapters have been written in ways which are intended to be useful to all interested in keeping abreast of developments, whether they be practitioners, teachers or students of the subject. Two of the chapters, those by Haddleton and Davis on radical polymerization, and by Feast and Khosravi on ring-opening metathesis polymerization (ROMP), build on accounts presented in Volume 1. It was recognized in that volume that the last word on ROMP had yet to be written, and that the ongoing development at that time of catalysts capable of being used with functionalized monomers and capable of giving living systems heralded further import ant developments. Likewise, it seemed likely even then that free-radical polymerization would soon warrant further discussion, and so it has proved to be with recent breaks-through in the area of living radical polymerization and in the control of molar mass through the use of catalytic chain transfer agents. The chapter by Sillion and Rabilloud on high-performance heterocyclic polymers goes some way towards recti- VI PREFACE fying the omISSIOn from Volume 1 of any significant coverage of polymers made by step reaction as opposed to chain reaction techniques. The account by Sawamoto and Kamigaito also covers an area afforded only a passing mention previously: living cationic polymerization. For so long, cationic polymerization has been regarded as a difficult area, given to irreproducible behaviour, and consequently has been a Cinderella subject in comparison with anionic polymerization, despite its long standing commercial utility. However, as the present account shows, this unsatisfactory situation has been transformed, not least through the efforts of Sawamoto and his group. The remaining four chapters all introduce topics new to this series. Two of these outline the application of physical processes to the control of polymerization: namely the use of ultrasound to modify the course of otherwise conventional polymerizations and the generation of polymers from plasmas. Both chapters are written by the leading exponents of the techniques: Price and Yasuda, respectively. The chapter by Brunelle covers the still emerging technology of the generation of high molar mass polymers by the opening-up and polymerization of large rings. This development has been driven largely by industrial requirements for polymerization processes that inherently are stoichiometrically balanced, that can be driven easily to high conversion, and that give poiymers which are free from residual monomers. Last, but by no means least, is the chapter by Hawker and Frechet covering exciting recent work on the synthesis of truly monodisperse synthetic polymers from multi-functional monomers (briefly previewed whilst still in its infancy in chapter 1 of the first volume): so-called dendritic macromolecules, or dendrimers. Dendrimers promise to have applications in areas as diverse as biomimetics, catalysis, drug-release and nano-reactors. Finally, it is to be noted that, with this volume, the series has gained a second editor. This was felt necessary in order to ensure a speedy production of the volume, before further developments threatened to render it out of date whilst still in the gestation stage. Both editors thank the authors who have contributed to Volume 2 for all their hard work, without which there would have been no book, and the publishers for their help and guidance with the project. J. R. E. G. C. E. Contributors D. J. Brunelle G E Research and Development Center, PO Box 8, Schenectady, NY 12301, USA T. P. Davis School of Industrial Chemistry, University of New South Wales, Sydney, New South Wales, Australia G. C. Eastmond The Donnan and Robert Robinson Laboratories, De partment of Chemistry, The University of Liverpool, PO Box 147, Liverpool L69 3BX, UK J. R. Ebdon The Polymer Centre, School of Physics and Chemistry, University of Lancaster, Lancaster LAI 4YA, UK W. J. Feast IRC in Polymer Science and Technology, University of Durham, Durham DHI 3LE, UK J. M. J. Frechet Department of Chemistry, Baker Laboratory, Cornell University, Ithaca, NY 14853-1301, USA D. M. Haddleton Department of Chemistry, University of Warwick, Coventry CV 4 7A L, UK C. J. Hawker IBM Research Division, Almaden Research Centre, 650 Harry Road, K93/801, San Jose, CA 95120-6099, USA M. Kamigaito Department of Polymer Chemistry, Kyoto University, Kyoto 606-01, Japan E. Khosravi IRC in Polymer Science and Technology, University of Durham, Durham DHI 3LE, UK G. J. Price School of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK G. Rabilloud CEMOTA, BP no 3, 69390 Vernaison, France M. Sawamoto Department of Polymer Chemistry, Kyoto University, Kyoto 606-01, Japan Vlll CONTRIBUTORS B. Sillion CEMOTA, BP no 3, 69390 Vernaison, France H. Yasuda Center for Surface Science and Plasma Technology, The University of Missouri-Columbia, College of Engineering, W2009 Engineering Building East, Columbia, Missouri 65211, USA Contents 1 Recent developments in radical polymerization 1 T. P. DAVIS and D. M. HADDLETON 1.1 Introduction 1 1.2 Iniferters in radical polymerization 3 1.3 Use of nitro so compounds as modifiers in radical polymerization 4 1.3.1 General features 4 1.3.2 Alkoxylamine initiators as sources of nitroso radicals 6 1.3.3 Use of arenediazonium compounds 10 1.3.4 Use of stable nitro so radicals in conjunction with peroxides 12 1.3.5 Use of nitroso radicals in the presence of aluminium alkyls 14 1.3.6 Summary 17 1.4 Chain transfer polymerization 17 1.4.1 Introduction 17 1.4.2 Coenzyme B12 chemistry 18 1.4.3 Chain transfer mechanism 19 1.4.4 Catalytic inhibition 26 1.4.5 CCT in copolymerization 26 1.4.6 Catalyst structures 27 1.4.7 Axial base ligands 28 1.4.8 Oligomer structure and synthesis 30 1.4.9 Applications of CCT polymerization 30 1.5 Related polymerization techniques 32 1. 6 Conclusion 33 References 34 2 Precision polymer synthesis by living cationic polymerization 37 M. SAW AMOTO and M. KAMIGAITO 2.1 Introduction 37 2.1.1 Background 37 2.1.2 Living cationic polymerization 37 2.1.3 Precision polymer synthesis: scope 40 2.2 Pendent-functionalized polymers 41 2.2.1 Vinyl ethers 41 2.2.2 Styrene derivatives 43 2.3 End-functionalized polymers 44 2.3.1 Vinyl ethers 45 2.3.2 Styrene derivatives 49 2.3.3 Isobutene 49 2.4 Macromonomers 50 2.5 Block polymers 52 2.5.1 Sequential living cationic polymerization 52 2.5.2 Transformation of mechanisms (method (6)-A-ii) 56 2.5.3 Polymer coupling 58 2.5.4 Living cationic polymerization from macroinitiator (method (7)) 58 2.6 Multiarmed and macrocyclic polymers 59 2.6.1 Multiarmed polymers 59 2.6.2 Macrocyc1ic polymers 63 References 64 x CONTENTS 3 Recent advances in metathesis polymerisation 69 W. J. FEAST and E. KHOSRAVI 3.1 Introduction 69 3.2 Well-defined initiators 69 3.3 Ring opening metathesis polymerisation (ROMP) 74 3.3.1 Synthesis of functional polymers 74 3.3.2 Aqueous ROMP 89 3.4 Combination of living ROMP with other polymerisation techniques 94 3.4.1 ROMP with aldol GTP 94 3.4.2 ROMP with anionic polymerisation 94 3.5 Ring closing olefin metathesis 98 3.6 Acyclic diene metathesis (ADMET): olefin metathesis in a step growth polymerisation 99 3.7 Materials via metathesis 101 3.7.1 Conducting polymers 101 3.7.2 New highly polar materials 106 3.7.3 Nanoscale clusters via microphase separated materials 107 3.7.4 Side chain liquid crystal polymers 108 3.7.5 Precursors to ceramics 111 References 112 4 Polymer synthesis using high intensity ultrasound 117 G. J. PRICE 4.1 Introduction 117 4.1.1 Origin of sonochemical effects 118 4.1.2 Cavitation 118 4.1.3 Factors affecting cavitation 120 4.1.4 Consequences of cavitation 122 4.2 Experimental techniques in sonochemistry 123 4.3 Ultrasonic degradation of polymers in solution 125 4.3.1 Kinetics of degradation 125 4.3.2 Mechanism of degradation 128 4.3.3 Applications of ultrasonic degradation 129 4.3.4 Summary 132 4.4 Polymerization initiated by radicals 133 4.4.1 The initiation process 135 4.4.2 The polymerization process 139 4.4.3 Summary 142 4.5 Suspension and emulsion polymerization 143 4.6 Ring opening polymerizations 144 4.7 Condensation polymerizations 147 4.8 Electrochemically promoted polymerizations 147 4.9 Polymerization employing organometallic reagents 150 4.9.1 Ziegler-Natta polymerizations 150 4.9.2 Poly(organosilanes) 152 4.10 Conclusions and future prospects 155 References 157 5 Plasma polymerization and plasma modification of polymer surfaces 161 H. YASUDA 5.1 Introduction 161 5.2 Domain of plasma polymerization and plasma surface modification 162 CONTENTS Xl 5.2.1 Comparison of vacuum deposition processes - chemical vapour deposition (CVD), plasma-assisted CVD and plasma polymerization 162 5.2.2 Plasma-induced polymerization 164 5.2.3 Plasma surface modification of polymers 165 5.2.4 Concept of 'polymer' in plasma polymerization 167 5.2.5 System dependency 167 5.2.6 Competitive ablation polymerization (CAP) principle 167 5.3 Fundamentals of plasmas 168 5.3.1 Types of plasmas 168 5.3.2 Distribution of energy and number of electrons 169 5.3.3 Excitation of organic molecules 173 5.3.4 Interaction of plasmas with surfaces 174 5.4 Ablation by plasmas 174 5.4.1 Chemical and physical etching of polymer surfaces ~~ 5.4.2 Influence of chemical structure of polymers 5.4.3 Influence of plasma gas /176 5.5 Plasma-state polymerization 177 5.5.1 Deposition rate 177 5.5.2 Mass balance in a plasma polymerization reactor 177 5.5.3 Growth mechanisms of plasma polymerization 179 5.5.4 Chemical structures of organic compounds for plasma polymerization 183 5.5.5 Dependence of properties of plasma polymers on chemical structure of monomer 184 5.5.6 Dependence of properties of plasma polymers on operational parameters 186 5.5.7 Dependence of properties of plasma polymers on substrate materials 187 5.6 Surface modification of polymers by non-polymer-forming plasmas 191 5.6.1 Plasma treatment of polymer surfaces 191 5.6.2 General principle (non-polymer-forming gases) 192 5.7 Post-plasma chemical reactions of trapped free radicals 193 5.8 General characteristics and significance of plasma polymers 193 References 195 6 Macrocycles for the synthesis of high molecular weight polymers 197 D. J. BRUNELLE 6.1 Introduction 197 6.2 Cyclic polymers: formation 199 6.2.1 Kinetically controlled formation and thermodynamic ring opening 199 6.2.2 Ring opening polymerization 200 6.3 Cyclic aromatic carbonates 200 6.3.1 Background 200 6.3.2 Cyclic oligomeric carbonates 201 6.4 Macrocyclic esters 217 6.4.1 Macrocyclic arylates 217 6.4.2 Macrocyclic araliphatic esters 220 6.5 Macrocyclic ethers and ethersulfones, etherketones and etherimides 223 6.6 Macrocyclic aramids 229 6.7 Conclusion 233 References 233 7 Heterocyclic polymers with high glass transition temperatures 236 B. SILLION and G. RABILLOUD 7.1 Introduction-general features 236