Some Other IUPAC Titles of Interest from Pergamon Press Books ANGUS: International Thermodynamic Tables of the Fluid State, 7-Propylene BATTINO: Oxygen and Ozone BROWN & DA VIES: Organ-Directed Toxicity—Chemical Indices and Mechanisms CIARDELLI & GIUSTI: Structural Order in Polymers EGAN & WEST: Collaborative Interlaboratory Studies in Chemical Analysis FREIDLINA & SKOROVA: Organic Sulfur Chemistry FUWA: Recent Advances in Analytical Spectroscopy GOETHALS: Polymeric Amines and Ammonium Salts GOODWIN & BRITTON: Carotenoids HÖGFELDT: Stability Constants of Metal-Ion Complexes, Part A: Inorganic Ligands KORNHAUSER, RAO & WADDINGTON: Chemical Education in the Seventies LAIDLER: Frontiers of Chemistry LAURENT: Coordination Chemistry—21 PERRIN: Stability Constants of Metal-Ion Complexes, Part B: Organic Ligands RIGAUDY & KLESNEY: Nomenclature of Organic Chemistry ST-PIERRE & BROWN: Future Sources of Organic Raw Materials STEC: Phosphorus Chemistry Directed Towards Biology TROST & HUTCHINSON: Organic Synthesis—Today and Tomorrow YOUNG: Hydrogen and Deuterium YOUNG: Oxides of Nitrogen Journals CHEMISTRY INTERNATIONAL, the news magazine for chemists in all fields of specialization in all countries of the world. PURE AND APPLIED CHEMISTRY, the international research journal publishing proceedings of IUPAC conferences, nomenclature rules and technical reports. INTERNATIONAL UNION OF PURE AND APPLIED CHEMISTRY (Macromolecular Division) in conjunction with Centre National de la Recherche Scientifique Université Louis Pasteur de Strasbourg MACROMOLECULES Main Lectures Presented at the 27th International Symposium on Macromolecules Strasbourg, France, 6-9 July 1981 Edited by H. BENOIT and P. REMPP Centre de Recherches sur Jes MacromoJecuJes Strasbourg, France PERGAMON PRESS OXFORD • NEW YORK • TORONTO • SYDNEY • PARIS • FRANKFURT U.K. Pergamon Press Ltd., Headington Hill Hall, Oxford 0X3 OBW, England U.S.A. Pergamon Press Inc., Maxwell House, Fairview Park, Elmsford, New York 10523, U.S.A. CANADA Pergamon Press Canada Ltd., Suite 104, 150 Consumers Rd, Willowdale, Ontario M2J1P9, Canada AUSTRALIA Pergamon Press (Aust.) Pty. Ltd., P.O. Box 544, Potts Point, N.S.W. 2011, Australia FRANCE Pergamon Press SARL, 24 rue des Ecoles, 75240 Paris, Cedex 05, France FEDERAL REPUBLIC Pergamon Press GmbH, 6242 Kronberg-Taunus, OF GERMANY Hammerweg 6, Federal Republic of Germany Copyright © 1982 International Union of Pure and Applied Chemistry AJJ flights Reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means: electronic, electrostatic, magnetic tape, mechanical, photocopying, recording or otherwise, without permission in writing from the copyright holders. First edition 1982 Library of Congress Cataloging in Publication Data International Symposium on Macromolecules (27th: 1981: Strasbourg, France) Macromolecules: main lectures presented at the 27th International Symposium on Macromolecules, Strasbourg, France, 6-9 July 1981. (IUPAC symposium series) 1. Macromolecules—Congresses. I. Benoit, Henri, 1921— II. Rempp, P. III. International Union of Pure and Applied Chemistry. IV. Université Louis Pasteur de Strasbourg. V. Title. VI. Series. QD380.I58 1981 547.7 81-23481 AACR2 British Library Cataloguing in Publication Data International Symposium on Macromolecules [27th: 1981: Strasbourg] Macromolecules.—(IUPAC symposium series) 1. Polymers and polymerization—Congresses I. Benoit, H. II. Rempp, P. III. International Union of Pure and Applied Chemistry. Macromoiecuiar Division IV. Series 547.7 QD380 ISBN 0-08-026226-0 In order to make this volume available as economically and as rapidly as possible the authors' typescripts have been reproduced in their originaJ forms. This method un­ fortunately has its typographical limitations but it is hoped that they in no way distract the reader. Printed in Great Britain by A. Wheaton 6- Co. Ltd., Exeter SCIENTIFIC COMMITTEE Honorary Chairmen G. Champetier (Deceased), C. Sadron Chairman H. Benoit Vice-Chairmen P. Sigwalt, C. Wippler Members A. Banderet, E. Bouchez, M. Carrega, A. Chapiro, J.-B. Donnet, E. Guillet, A. Guyot, A. Kepes, A.-J. Kovacs, 3. Minoux, J. Neel, C. Pinazzi, C. Quivoron, P. Rempp, M. Rinaudo, B. Sillion, A. de Vries INTERNATIONAL UNION OF PURE AND APPLIED CHEMISTRY IUPAC Secretariat: Bank Court Chambers, 2-3 Pound Way, Cowley Centre, Oxford OX 4 3YF, UK PREFACE This book is a collection of the Main Lectures which were delivered during the 27th IUPAC Symposium on Macromolecules that was held in Strasbourg , July 6 to 9, 1981. The purpose of these lectures was to present and illustrate each of the themes selected by the scientific committee. These fields were chosen for their importance in Macromolecular Science and with the feeling that they were representative of the present trends in Polymer Research. Qualified lecturers were selected for their own con­ tributions to the corresponding domains. They were asked before­ hand to report not only on their own work, but also on the present state of knowledge and on the possible developements and potential applications in the field in which they are involved. The authors of Main Lectures originate from countries in which Polymer Science is most actively investigated, and a world-wide distribution of invited speakers was achieved. These considerations will explain the broad field covered by this book. It contains topics ranging from Pure Polymer Chemistry to Polymer Physics and Polymer Technology. This illustrates the diversity of the interest of scientists involved in Polymer Science and shows once more the pluridisciplinarity of our field. In a certain way, this is not the kind of book in which a specialist of a given topic will gain new information or results in his domain of interest. The purpose of this book is to allow anybody interested to get precise and up-to-date information on the present state of research in the domains selected. It should be specially valuable for scientists who try to keep contact with progress in Polymer Science beyond their own field of activity. It should also provide for new ideas, encourage collaboration, and possibly lead to new applications. Besides the Main Lectures some 320 short communications have been presented at the IUPAC Symposium in Strasbourg. These short communications will not be published as such, but two volumes of preprints have been made available for the participants. Addi­ tional copies can be obtained from the Centre de Recherches sur les Macromolécules by anybody wanting more details on the Meeting. Twenty-nine years ago, a similar IUPAC Symposium was held in Strasbourg, gathering fewer than 200 scientists, but most of the pioneers of Polymer Science. In 1981 there were about 1000 people attending, on selected topics. One can rejoice in the huge developements of our scientific discipline, for it illustrate the growing interest in Polymer Science and Technology and the increa­ sing importance of Scientific Research in the present world. We want to express our deep appreciation to the authors of the Main Lectures for having prepared and made available a written version of their presentation to the IUPAC Symposium. We know that this takes time and requires much care, and we feel indebted to them. Preface We would also like to express our warmest thanks to all the researchers, technicians and students of the Centre de Recherches sur les Macromolécules, Strasbourg, and of the Ecole d'Application des Hauts Polymères, Strasbourg for having participated actively and willingly in the organisation of the Meeting. Without their time-consuming help it would have been impossible to set up such a Symposium. Last, but not least, we would like to acknowledge the financial support of Franch Public Research Bodies (CNRS, DGRST, DRET) and of numerous French Industries devoted to Polymer production and processing. H. BENOIT P. REMPP Centre de Recherches sur les Macromolécules 6,rue Boussingault - 67083 STRASBOURG(France) Septembre 1981 ON COMMON TENDENCIES OF NON-EQUILIBRIUM POLYCONDENSATION V.V. Korshak Institute of Organo-Element Compounds, Acad. Sci. USSR, 117813 Moscow, USSR Abstract - The chemistry of polycondensation processes has gained a rather rapid development at the present time. All known polycondensation reactions can be combined into two groups: 1; equilibrium and 2) non-equilibrium polycondensa­ tion. They differ in the equilibrium constant of the process under investigation. Equilibrium polycondensation includes reactions with K <10-% reactions with K > 10-* belong to non-equilibrium process. The difference between these two polycondensation types shows up in the properties of the re­ sulting polymers, the mechanism of elementary reactions, the nature and mechanism of catalyst action, the kinetics, the molecular weight distribution, the mechanism of copolycon- densation, the structure of copolymers and the like. Various side reactions also occur. As a result, anomalous units are formed in the macromolecule which gives rise to "raznozven- ny" (different-unit) polymers. Their structure can be des- cribed by the following formula: . ^ . ^^ with M as normal unit and A as anomalous one. Anomalous units and, as a consequence, polymer raznozvennost (different-unit structure) have been shown to present in different classes of polymers prepared by polycondensation methods. Catalysts strongly influence the non-equilibrium polycondensation pro­ cess. The use of tertiary amines makes it possible to cont­ rol the structure of the resulting polymers and to produce conformational-specific polymers. In 1833 Gay-Lussak and Pelouze obtained the first synthetic polyester by polycondensation of the hydroxycarboxylic acid (1). In the following years we observed an ever-increasing number of investigations concerning the poly­ condensation field (2-4). Thus at the present time the polycondensation as a synthetic process has gi­ ven a large number of polymeric structures to science and engineering and played an important role in the development of basic concepts of polymer science (2-4;. The rapid progress of investigations of polymer synthesis by polycondensation has enriched the polymer science with new reactions for polymer preparation, made it possible to understand the mechanism of poly­ condensation processes and enlarged a store of science with many new poly­ mers. Some Specific Features of Polycondensation Polycondensation processes essentially differ from polymerization processes (2 & 3). First of all, attention should be given to great universality of polycondensation processes and, consequently, to great variety of structures prepared with their help. The structures obtained by polymerization are less diversified than those obtained by polycondensation. Among the polymers ob­ tained by polycondensation is a great number of polymers having high thermo- stability, conductive polymers, physiologically active polymers and the like. Although the polycondensation is studied nowadays by a more narrow circle of workers than the polymerization, the effectiveness of their synthetic inves­ tigations is rather high (4). Thus, when considering various polymeric com­ pounds reported in scientific papers one can find that nearly 50% of new po­ lymers described in the literature are polymers produced by means of poly- l 2 V. V. Korshak condensation reactions (4). And finally, 1 would say, the most important di­ fference consists in that these two processes strongly differ from each ot­ her in the number of chemical reactions used in both cases. In polymeriza­ tion we make use only of two chemical reactions: addition to double and tri­ ple bonds between two atoms or addition to cycles. As to polycondensation, some dozens of chemical reactions are used in it already at the present time, and the number of reactions being drawn into these transformations increases from year to year. This is also true of a very important field such as biopolymers which are also mainly formed by means of polycondensa­ tion methods. It should be emphasized that polycondensation is of great importance as a method of natural polymer synthesis, since many significant biopolymers such as proteins, nucleic acids, natural caoutchouc, cellulose, starch, glycogen, chitin, pentosanes and many other polymers, as well as ferments, enzymes, and hormones are formed in living organisms by means of various polycondensation processes, that is, this process is widely repre­ sented in nature. And such still quite a new, but very promising domain of polymer science as inorganic polymers is almost completely the area of poly­ condensation application, because most heterochain inorganic polymers are prepared just by polycondensation (5 & 6). After such brief characteristic of specific features of polycondensation we dwell on the modern state of this field, giving particular consideration to distinguishing features of non-equilibrium polycondensation, to causes of the rise of raznozvennost in non-equilibrium polycondensation, as well as to the process of macromolecule formation and the effect of reaction conditi­ ons, catalysts and solvents, that is, to questions which nowadays determine the progress in the polycondensation that finally determines the perspecti­ ves of developments in this field• Types of Polycondensation Investigation of common tendencies of polycondensation processes has led us to the conclusion that all known polycondensation reactions can be combined into two large groups called equilibrium and non-equilibrium polycondensa­ tion (2,3t7>8). The difference between them is largely determined by the value of equilibrium constant (K„) of the process under investigation. ïïqui- P o librium polycondensation includes reactions with K„ < 10-^, reactions with o P K > 1<y belong to non-equilibrium polycondensation (7 & 8) . IT The difference between these two types of polycondensation shows up also in the properties of the resulting polymers, the mechanism of the proceeding reactions, the nature and mechanism of catalysts, the kinetics, molecular weight distribution, the mechanism of copolycondensation, the structure of copolymers, and other specific features of the process that will be shown below. The non-equilibrium process has been studied not so comprehensively, and this put the task of a detailed investigation of laws governing its course. The imortance of this trend is caused by that just non-equilibrium polycon­ densation makes it possible to synthesize polymers at a higher rate and to prepare rather high molecular weight polymers with new unit structures and interesting complex of physical and chemical properties (7 9t10). f Functionality of Monomers Carothers (11) formulated the rule of monomer functionality stating that li­ near polymers are formed when the monomers are bifunctional. If they are three-functional and higher, a gel formation occurs and a steric, insoluble and infusible polymer is formed. This rule needs radical changes, however, because there are many cases when this relationship is not confirmed, and three- and tetrafunctional monomers proved to be capable of forming polymers with linear macromolecules. This is possible in case of significant diffe­ rence in reactivity of functional groups, when the more reactive groups react earlier forming a linear polymer. This can be exemplified by the reac­ tion of glycerine with phthalic anhydride« Reaction conditions are also of importance. For instance, the non-equilibri­ um polycondensation of tetramine with terephthaloyl chloride gives a three- dimensional insoluble polymer. If the reaction proceeds in pyridine hydro- chloride or in the salt of another aminé, a linear polymer is formed, al­ though the monomer is tetrafunctional. But in this medium it acts as a di- functional compound (13): On Common Tendencies of Non-Equilibrium Polycondensation 3 H NAJ^MH -CORCO-NH-V^im-COKCO- "2O" v ""20 E^YYm2 HCl-C^N , HCl.H^YY^- 1101 01CORCOC1 .. HC1 -H„N WNH «HOI 0 ^ ^, -CORCO-NH'V^NH-CORCO- (1) There is a distinct difference between potential or structural and real or reactive functionality (13)» Steric factors can be of rather essential im­ portance. This can be exemplified by non-equilibrium polycondensation reac­ tions, for instance, by the formation of various polyheteroarylenes, when tetrafunctional compounds such as tetraamines, dihydroxydiamines, dithiadia- mines, tetracarboxylic acids, diaminodicarboxylic acids and other similar compounds of the general formula: (2) are used as monomers. Important in this case is the mutual position of func­ tional groups. If the position enables the formation of five- and six-mem- bered cycles, linear macromolecules of heterocyclochain polymers are formed due to a steric effect of functional groups. This fact demonstrates the pos­ sibility of preparing linear polymers from three- and tetrafunctional mono­ mers that earlier was considered to be impossible. Therefore, it should be concluded that important for the formation of linear polymers is not only the common functionality of monomers, but also the corresponding favourable mutual position of functional groups in the structural unit or monomers as well as the effect of reaction medium and reaction conditions in the course of polycondensation. This makes one to pose differently the problem of the importance of monomer fimctionality in a non-equilibrium polycondensation The Rule of Non-Equivalence of functional Groups As known, the rule of non-equivalence of functional groups holds for the reactions of dicarboxylic acids with glycols or diamines and generally for all cases of polycondensation when the initial substances are bifunctional (2,13). Tais principle provides a means of controlling the molecular weight of polymers prepared by equilibrium polycondensation when different quanti­ ties of monofunctional substances or an excess of one of the monomers are added (13). Figure 1 shows the changes of found and calculated molecular weight as a function of the excess of one of the monomers. Investigations of this re­ lation for non-equilibrium polycondensation with initial substances having higher functionality showed that in most cases here again the excess of one of the initial substances has similar effect in the reactions of tetrafunc­ tional monomers decreasing the molecular weight proportionally to the excess of one of the monomers. Such a dependence was observed in many cases of non-equilibrium polycondensation. The reaction of various tetrafunctional nucleophiles with tetracarboxylic acids or their derivatives follows the rule of non-equivalency of functio­ nal groups, as shown in the general form in Fig. 2. 4 V. V. Korshak 100 80 SO hO 20 0 20 40 60 80 100 Excess Excess component A component B Fig. 1. Dependence of the molecular weight of polyamides on the excess of one of the monomers. 1,2) calculated, 3) found molecular weight. P - coefficient of polymerization. \ red. k 1 2 M Nucleofile Electrofile excess,mole-% excess, mole- Fig. 2. Influence of excess monomers on the solution viscosi­ ty of polymers prepared from various tetrafunctional monomers (dihydrazides of dicarboxylic acids, bis-o-aminophenols, di- anilinodiamines, diamides of bis-anthranyl acids; with poly- carboxylic acids. Figure 3 shows the dependence of the viscosity of polyimide solution on the excess of initial substances in the reaction of diamine with pyromellitic dianhydride (16). The same occurs in the reaction of carboranedicarboxylic acid dichloride with tetraamines, as shown in Fig. 4 (16). Thus, the above examples evidence rather clearly a distinct dependence of the molecular weight of polymer to be synthesized on the excess of one of the monomers also in the case of tetrafunctional monomers and, consequently, "the rule of non-equivalency of functional groups" is also valid for many- functional monomers in a non-equilibrium polycondensation (3 & 13).