Developments In Crystalline Polymers 2

Modern society makes increasing demands for novelty in materials and their properties which are ever more exacting. Crystalline polymers are in the forefront of this demand and improvements are constantly occurring across the entire range from existing materials of high tonnage to novel materials with application in information technology. The developments recorded in this volume reflect this situation. Chapter 1 is a comprehensive review of the polymer PHB, poly(hydroxybutyrate), which is new to industrial manufacturing but is a naturally occurring substance. It has potentially valuable properties but has excited interest especially because it is biodegradable. It may, therefore, provide one means of reducing environmental pollution. Improvements in existing materials, beyond those which are ob tainable by optimization of known variables, are most likely to come from understanding of structure-property relationships. Polymer is able to make effective science has now reached the stage where it synthesis of information from complementary techniques, leading to rapidly deepening understanding. Chapters 2, 3 and 4 are all con cerned with technical developments which are contributing substan tially to this synthesis. The possibilities of electron microscopy, specifically the characterization of lamellar microstructure, have been transformed by permanganic etching. Now real organization (which can be very different from what had previously been inferred) can be used as a basis for explaining polymeric properties. In Chapter 3, Mitchell and Windle give a critical account of the assessment of orientation in liquid crystalline polymers, a rapidly developing new field in which they have played a leading part.

The last four years since the publication of the first of this series have seen further striking developments in both the science and technology of oriented polymers. In particular, polymers possessing very high degrees of molecular orientation are now quite commonplace, and this is reflected by the inclusion of five chapters dealing with ultra-high modulus polyethylene fibres, oriented liquid crystalline polymers (both lyotropics and thermo tropics) and polydiacetylene single crystal fibres. At the same time there is continuing interest in the structure and properties of less highly oriented polymers and in the mechanisms of deformation in polymers. It is therefore good to have these themes represented also. I should like to thank the contributors for adhering to a rather tight time schedule, and the publishers for their cooperation, so that this book can provide up-to-date reviews of the state of the art in a rapidly moving area of polymer science. I. M. WARD v CONTENTS Preface.... . . . .. . . . . .. ... . . . . . . . . . .. . . .. . . . . . . ... ... v List of Contributors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IX 1. Polymer Single Crystal Fibres ........................ .

This volume contains an eclectic collection of 22 papers on liquid crystalline polymers presented at the Sixth Polymer Workshop, in the series sponsored by the European Science Foundation, entitled: 'Liquid Crystal Polymer Systems', in Gentofte, Denmark, 12-14 September 1983. Since a contribution to this volume was strictly voluntary, and in some cases represents a considerably expanded version of that which was presented, it is strictly speaking not correct to term this a 'proceedings'. A description of the aims and purposes of the European Science Foundation with respect to the polymer area has been presented in: Shell Polymers, Vol. 5, No.2, pp. 34-35, 1981. The papers given here represent a cross-section of current research interests in liquid crystalline polymers in the areas of theory, synthesis, characterization, structure-property relationships and applications. At least some of the current interest is motivated by attempts to practically exploit the novel properties of these materials in the developing tech nologies of high strength fibres and advanced materials for constructional purposes, but also for functional materials in the areas of information retrieval, electronics and opto-electronics applications. The editor wishes to thank all those involved for their courtesy and co-operation.

This book provides a comprehensive overview of various self-assemblies in liquid crystalline polymers and their electrical, optical, mechanical, and flame retardant properties. Liquid crystalline polymers are unique self-assembled, functional soft materials with electrical, magnetic, and thermal responses which find potential applications in numerous areas. As well as providing an overview of their synthesis, self-assembly and dynamics the various applications are also discussed. Such applications as liquid crystalline elastomers, light responsive actuators, optical reflectors, gas barrier films, and even flame retardant polymers will be presented. The book is a useful resource for undergraduates, postgraduates and experienced researchers.

The Physics of Polymers presents the elements of this important segment of material science, focusing on concepts above experimental techniques and theoretical methods. Written for graduate students of physics, material science and chemical engineering and for researchers working with polymers in academia and industry, the book introduces and discusses the basic phenomena which lead to the peculiar physical properties of polymeric systems. The revised and expanded Third Edition includes a new chapter dealing with conjugated polymers, explaining the physical basis of the characteristic electro-optic response, and the spectacular electrical conduction properties of conjugated polymers created by doping.

Properties of Polymers: Their Correlation with Chemical Structure; Their Numerical Estimation and Prediction from Additive Group Contributions summarizes the latest developments regarding polymers, their properties in relation to chemical structure, and methods for estimating and predicting numerical properties from chemical structure. In particular, it examines polymer electrical properties, magnetic properties, and mechanical properties, as well as their crystallization and environmental behavior and failure. The rheological properties of polymer melts and polymer solutions are also considered. Organized into seven parts encompassing 27 chapters, this book begins with an overview of polymer science and engineering, including the typology of polymers and their properties. It then turns to a discussion of thermophysical properties, from transition temperatures to volumetric and calorimetric properties, along with the cohesive aspects and conformation statistics. It also introduces the reader to the behavior of polymers in electromagnetic and mechanical fields of force. The book covers the quantities that influence the transport of heat, momentum, and matter, particularly heat conductivity, viscosity, and diffusivity; properties that control the chemical stability and breakdown of polymers; and polymer properties as an integral concept, with emphasis on processing and product properties. Readers will find tables that give valuable (numerical) data on polymers and include a survey of the group contributions (increments) of almost every additive function considered. This book is a valuable resource for anyone working on practical problems in the field of polymers, including organic chemists, chemical engineers, polymer processers, polymer technologists, and both graduate and PhD students.

Proceedings of the NATO Advanced Research Workshop, Cap d'Agde, France, September 9-14, 1990