Table Of Content

New Concepts in Polymer Science Structure and Properties of Conducting Polymer Composites New Concepts in Polymer Science Previous titles in this book series: Interaction of Polymers with Bioactive and Corrosive Media A.L. Iordanskii, T.E. Rudakova and G.E. Zaikov Immobilization on Polymers M. I. Shtilman Radiation Chemistry of Polymers V.S. Ivanov Polymeric Composites R. B. Seymour Reactive Oligomers S. G: Entelis, V.V. Evreinov and A.I. Kuzaev Diffusion of Electrolytes in Polymers G.E. Zaikov, A.L. Iordanskii and V.S. Markin Chemical Physics of Polymer Degradation and Stabilization N. M Emanuel and A.L. Buchachenko Of related interest: Journal of Adhesion Science and Technology Editors: K.L. Mittal and W.J. van Ooij New Polymeric Materials Editor-in-Chief: F.E. Karasz Journal of Biomaterials Science, Polymer Edition Editors: C.H. Bamford, S.L. Cooper and T. Tsuruta Composite Interfaces Editor-in-Chief: H. Ishida New Concepts in Polymer Science Structure and Properties of Conducting Polymer Composites VE. Gui' Boca Raton London New York CRC Press is an imprint of the Taylor & Francis Group, an informa business First published 1996 by VSP BV Published 2021 by CRC Press Taylor & Francis Group 6000 Broken Sound Parkway NW, Suite 300 Boca Raton, FL 33487-2742 © 1996 by Taylor & Francis Group, LLC CRC Press is an imprint of Taylor & Francis Group, an Informa business No claim to original U.S. Government works ISBN 13: 978-90-6764-204-0 (hbk) This book contains information obtained from authentic and highly regarded sources. Reasonable efforts have been made to publish reliable data and information, but the author and publisher cannot assume responsibility for the validity of all materials or the consequences of their use. The authors and publishers have attempted to trace the copyright holders of all material reproduced in this publication and apologize to copyright holders if permission to publish in this form has not been obtained. If any copyright material has not been acknowledged please write and let us know so we may rectify in any future reprint. Except as permitted under U.S. Copyright Law, no part of this book may be reprinted, reproduced, transmitted, or utilized in any form by any electronic, mechanical, or other means, now known or hereafter invented, including photocopying, microfilming, and recording, or in any information storage or retrieval system, without written permission from the publishers. For permission to photocopy or use material electronically from this work, please access www.copyright.com (http://www.copyright.com/) or contact the Copyright Clearance Center, Inc. (CCC), 222 Rosewood Drive, Danvers, MA01923, 978-750-8400. CCC is a not-for-profit organization that provides licenses and registration for a variety of users. For organizations that have been granted a photocopy license by the CCC, a separate system of payment has been arranged. Trademark Notice: Product or corporate names may be trademarks or registered trademarks, and are used only for identification and explanation without intent to infringe. Visit the Taylor & Francis Web site at http:// www. tay lorandfrancis. com and the CRC Press Web site at http// www.crcpress.com CIP-DATA KONINKLIJKE BIBLIOTHEEK, DEN HAAG Gui' V.E. Structure and properties of conducting polymer composites / V.E. Gui'. -Utrecht: VSP. -(New Concepts in Polymer Science, ISSN 0928-1584) With ref. ISBN 90-6764-204-5 bound NUGI 841 Subject headings: polymers. Contents Introduction vii Chapter 1. The main principles of the increase of electric conductivity of polymer composites 1 1.1. Various types of filler particle distribution in polymer matrix 2 1.2. Fractal structure of electrically conductive filler 4 1.3. The formation of electric current path in electrically conductive polymer composites 8 1.4. Experimental data on organisational forms of electrically conductive filler particles in a polymer matrix 15 1.5. Electric conductivity mechanisms of electrically conductive polymer composites 18 Chapter 2. Selection of basic polymer or polymer matrix 27 2.1. The analysis of exploitation conditions and required material properties 27 2.2. Polymers most commonly used for processing and article making 28 2.3. Electrically conductive polymers 34 2.4. Principles of mathematic modelling of ECPC content selection 54 Chapter 3. Selection of electrically conductive filler 61 3.1. Metal fillers 61 3.1.1. The mechanism of electric conductivity by particles of metal filler 61 3.1.2. Linear dependence of electric conductivity of metal-filled ECPC 65 VI Contents 3.1.3. Manufacture and properties of the metal powder 68 3.1.4. The influence of physical and chemical factors on the distribution of highly dispersed metal particles 77 3.1.5. Compulsory formation of current conductive paths in ECPCs 78 3.1.6. The influence of metal fillers on ECPC properties 90 3.1.7. The influence of magnetic field on the properties of ECPCs 102 3.2. Carbon-graphite fillers 105 3.2.1. The influence of structure and chemical composition of particle surface of carbon-graphite fillers on electric conductivity of ECPCs 105 3.2.2. Methods of increasing electric conductivity in ECPCs with carbon graphite fillers 112 3.3. Electron self-conductive polymers 123 Chapter 4. Estimation of working ability of electrically conductive polymers 147 Chapter 5. The main spheres of ECPC application 167 5.1. The principles of application of ECPCs instead of traditional materials 167 5.2. Some spheres of ECPC application 168 5.2.1. Electromagnetic radiation shielding 168 5.2.2. Antistatic articles 170 5.2.3. Heaters 173 5.2.4. Resistors and transducers 179 5.2.5. Assembling of electronic device components 183 5.2.6. Medicinal goods 184 5.2.7. Cables 185 5.2.8. Articles for technical purposes 186 5.2.9. Other articles made from ECPCs 188 5.3. Conclusion 190 References 193 Introduction The development of the principles of electrically conductive polymer composites and the creation of a wide variety of such materials are, no doubt, among the most important events of the 20-th century. A combination of unusual and valuable properties of polymer materials made them practically irreplaceable in many applications in science and technology. Thus, for example, it is impossible to find an alternative solution for apply- ing elastomers that are capable of deforming by a thousand per cent and then restoring their initial form after the applied force is removed. If, for what- ever reason, humankind had no possibility of using polymer materials, then the development of civilization would have followed a different path. For example, aircraft could not (because of the absence of the material for inner tire and protectors) be landed at current speeds. And there are many such examples. However, for a long time, polymer materials were excluded from a number of applications which required electrical conductivity. If one obtained a polymer material that was electrically conductive, it usually was a solid-like substance, which would decompose on melting. Consequently, its processing and forming into various articles met extraordinary difficulties. The situation changed radically when it was found that the introduction of some kinds of carbon black into elastomer compositions produced a new prop- erty — electrical conductivity [1]. The study of this phenomenon has shown that a polymer composition begins conducting electricity at a certain threshold concentration of additive [2, 3]. B.A. Dogadkin has shown that not all kinds of carbon black are able to give the elastomer composition the ability to conduct electric current. Such a prop- erty is provided by carbon whose particles are distributed in the polymer matrix as chain structures and not as lumps [2]. The development of electron microscopy as a method of studying polymer composition established an important law that holds for all known polymer compositions with an electrically conductive filler. The law says: providing certain other conditions are fulfilled, the composition becomes electrically conductive when particles of electrically conductive filler form a continuous chain structure, penetrating the material from the point of entry of electric current to viii Introduction the place where it leaves the polymer material [4-8]. The condition for the formation of such structures is the presence of the definite picture of interaction between polymer and low-molecular electrically conductive components [8, pp. 12-13]. Soon after, the idea of the compulsoriness of the formation of chain structures of electrically conductive components was realized in practice (see for example [9-17]). Thus, at present, conditions exist to obtain articles from polymer materials with a range of specific properties and which are able to conduct electric current in given directions. It has become possible to form electrically conductive structures of any configuration, which penetrate the volume of the polymer composition. The practical significance of scientific research, aimed in this direction could not be over-estimated. Thus at present, for example, resistors in microelec- tronic devices (including electrically conductive compositions) are included into the structure of some 50-60% of components. Adhesives based on electrically conductive polymer compositions (ECPCs) are often used for con- nection of hybrid integral and printed plates. Their principal advantage is that their application can help to avoid using soldering in cases when the article could not stand high temperatures. Of equal importance for practical application are the questions of the creation of many point contacts [9-12]. A special chapter (Chapter 5) is devoted to practical applications of ECPCs. Electric current passing through an ECPC is accompanied by sufficient changes of direction and the rate of degradation processes. The study of such processes is important not just for preventing unwanted degradation processes, but for prognosis of the working life of articles that are produced from ECPCs [18]. The exhaustion of the interior of the Earth, which is connected with the continuous digging out of mineral resources, the occurrence of ozone holes, the appearance of the hotbed effect and other ecological factors made it necessary for us to use raw resources and energy more efficiently. In developed countries, a decrease of landfill sites and profligate use of metals and other materials that require a lot of raw mineral resources and energy are observed. However, heavy metals play less and less role in the production of materials. The application of ECPCs instead of metal wires can become one factor contributing to an improvement of the ecological situation. The present monograph is devoted to the above mentioned aspects of the problem of the structure and properties of electrically conductive polymer composites. This is the first attempt to systematize modem ideas on the intercon- nection of the structure and properties of ECPCs with particular reference to the influence of electric current on the kinetics and the direction of chemical processes of interaction of such systems with air oxygen. This monograph will undoubtedly have its shortcomings, but the author gives his grateful thanks to Introduction IX his colleagues who felt able to make their comments and suggestions on the subject.