Polymers - Properties and Applications – serie

This book deals with the most important substances used as additives in the plastics industry to improve the properties of polymer-based materials. Each chapter deals with a particular type of additive based on the type's definition, structure, and classification according to main effects on polymeric materials. The mechanism of the additive efficiency and its effects on basic properties of specific polymers are discussed and a survey of its important qualities and practical applications is given. Each chapter is introduced by a theoretical analysis of the practical and technological importance of the ad­ ditive. The book is mainly intended for students in technical colleges, polytechnics and universities who are studying plastics technology and macromolecular chemistry as part of their general curriculum and for technologists in industry engaged in development, sales, technical service and production functions, and applications of plastics. An elementary knowledge of chemistry, physical chemistry and polymer science at the technical college level is assumed. Prague and Montreal, December 1982 J. Stepek, H. Daoust Table of Contents Introduction .

The discoveries of organometallic catalysts for olefin polymerization by Karl Ziegler and that of stereoregular olefin polymers by Giulio Natta are probably the two most important achievements in the areas of catalysis and polymer chemistry in the second half of this century. They led to the development of a new branch of chemical industry, and to a large volume production of high-density and linear low-density polyethylene, isotactic polypropylene, ethylene-propylene rubbers, isotactic poly­ I-butene, and poly-4-methyl-l-pentene. These discoveries merited the Nobel prize, which was awarded to K. Ziegler and G. Natta in 1963. The initial works of Ziegler and Natta were followed by an "explosion" of scientific papers and patents covering all aspects of polymerization chemistry, catalyst synthesis, and polymerization kinetics as well as the structural, chemical, physical, and technological characteristics of stereo regular polyolefins, polydienes, and olefin copolymers. It is sufficient to say that in the twenty-five years after the first publications more than 15,000 papers and patents appeared on subjects related to the area. . The development brought about the establishment of several prominent groups of scientists occupied with the study of olefin polymerization. The most important of these were scientific schools in Italy, Germany, England, the United States, Japan, the Soviet Union, Czechoslovakia, and Venezuela. In addition, many major chemical and petrochemical corporations throughout the world established labora­ tories devoted to the development of the technology of catalyst synthesis and olefin polymerization.

"The sciences as a whole are slowly but gradually drifting away from life and are only returning after adetour". Goethe Detours should be avoided. The picture we are presenting here of the current theory in phenolic resin chemistry and the technical application of phenolic resins is based on day-to-day experiences in research, pro4uction and marketing, however, with the background of economic relevance. This book, then, is not to be regarded as a systematic collection and evaluation of the literature, although the literature up to July, 1978 has generally been taken into consideration. The audience to which this book is directed is wide-ranging: chemists, engineers, marketing professionals and students. We show where the first fully synthetic polymers, phenolic resins, stand today and what their future iso Taking a look back over their development, one is only more deeply convinced that after a wide variety of adaptions, they still possess the tech­ nical and economic strengths which allow for their further market growth and with it, a full appreciation of their value. We would like to extend our gratitude to all friends and promotors, in particular to those who helped and encouraged us with advice and assistance. Andre Knop Walter Scheib Frankfurt, January 1979 Table of Contents Historical and Economic Development of Phenolic Resins 1. History . . . 1 1.1. 1.2. Market Position 5 References. . 8 Raw Materials . 10 2. 10 2.1. Phenols. . . 10 2.1.l. Physical Properties of Phenol .

The development of polymers as an important class of material was inhibited at the first by the premature failure of these versatile compounds in many applications. The deterioration of important properties of both natural and synthetic polymers is the result of irreversible changes in composition and structure of polymers molecules. As a result of these reactions, mechanical, electrical and/or aesthetic properties are degraded beyond acceptable limits. It is now generally recognized that stabilization against degradation is necessary if the useful life of polymers is to be extended sufficiently to meet design requirements for long-term applications. Polymers degrade by a wide variety of mechanisms, several of which affect all polymers through to varying degree. This monograph will concentrate on those degradation mechanisms which result from reactions of polymers with oxygen in its various forms and which are accelerated by heat and/or radiation. Those stabilization mechanisms are discussed which are based on an understanding of degradation reaction mechanisms that are reasonably well established. The stabilization of polymers is still undergoing a transition from an art to a science as mechanisms of degradation become more fully developed. A scientific approach to stabilization can only be approached when there is an understanding of the reactions that lead to degradation. Stabilization against biodegradation and burning will not be discussed since there is not a clear understanding of how polymers degrade under these conditions.

Thirty years ago, Zavoisky, in Moscow (USSR), reported the first successful experi­ mental observations of the ESR phenomenon. Its application to polymer problems began about 20 years ago. ESR belongs to the most specific and useful methods in the study of polymer reactions. The main purpose of this book is to collect the present available information on the applications of electron spin resonance (ESR) spectroscopy in polymer research. The book has been written both for those who want an introduction to this field, and for those who are aheady familiar with ESR and are interested in application to polymers. Therefore, the fundamental principles of ESR spectroscopy are first out­ lined, the experimental methods including computer applications are described in more detail, and the main emphasis is on the application of ESR methods to polymer problems. Many results obtained are only briefly treated for lack of space. The authors hope that this book will provide a useful source of information by giving a coherent treatment and extensive references to original papers, reviews, and discussions in monographs and books. In this way we hope to encourage polymer chemists, organic chemists, biochemists, physicists, and material scientists to apply ESR methods to their research problems.

Many excellent volumes have been written on the chemistry of cellulose and its derivatives. Judging by the number of conferences which have been assembled to deal with the topic, cellulose and its derivatives continue to arouse great scientific interest. Matching this interest has been the development in copolymer science and technology. In both instances the driving force has been the search for products having useful, new or interesting properties. It appeared inevitable that these two concepts would be brought together at some time in the research and development of cellulosic copolymers. That time has arrived. In assembling this text our aim was to present an informative account of the chemistry and technology of cellulosic copolymers. As such, we intended that the contents be of interest to all those concerned with the production and use of cellulosic products whether in academic or industrial circles. Sections of the text should be of value in undergraduate and post-graduate teaching, provided the student is given guidance in following the text. The volume is divided into eight chapters, each dealing with factors which are relevant to an under­ standing of cellulosic copolymers. Each chapter carries its own bibliography and is reasonably self-contained.

The present monograph is intended as an introduction into a field which certainly did not receive proper attention in the past. It is one of the aims of this book to verify this suppo­ sition. The author hopes to show that the technique of the measurement of flow birefringence can fulfil an important com­ plementary task in polymer melt rheology. From this point it is expected that the present monograph will attract the atten­ tion of polymer scientists in general, and of rheologists and process engineers in particular. Certainly, the fourth chapter will appeal to the latter group. As a teacher in polymer science and technology the author wants to address also the group of the graduate students. In fact, the standard knowledge acquired during usual university studies in chemistry, physics or engineering does not enable a quick start of research activities in the field of polymer melt rheology. Certainly, in this typically interdisciplinary field everyone can lay emphasis on matters which are familar to hirn because of his preceding education. Significant research activities, however, can only be generated on the basis of a more universal knowledge. In the absence of this knowledge beginners have to rely upon the guidance of their supervisors for an unduly long period. Otherwise they take the risk of losing too much of their costly time. This holds in particular for the experimentalists who cannot be dispensed from being familiar with the necessary theoretical background.

This book has grown out of several courses oflectures held at the University of Mainz in the years 1978 to 1981, at the Ecole Poly technique Federal, Lausanne, and at the University of Fribourg, Switzerland. The last two courses were held in the framework of the "3e Cycle" lectures in June 1981. According to this genesis, the emphasis of the book lies on a unified and concise approach to introducing polymer spectroscopy rather than on completeness which, by the way, could hardly be achieved in a single volume. In contrast to other books on this subject, equal weight is given to electronic spectroscopy, vibrational spectroscopy and spin resonance techniques. The electronic properties of polymers have been increasingly investigated in the last ten years; until recently, however, these studies and the spectroscopic methods applied have not generally been considered as part of polymer spectroscopy. The increasing use of electronic spectroscopy by polymer researchers, on the other hand, shows that this type of spectroscopy provides efficient tools for gaining insight into the properties of polymers which cannot be obtained by any other means.

The development of polymers as an important class of material was inhibited at the first by the premature failure of these versatile compounds in many applications. The deterioration of important properties of both natural and synthetic polymers is the result of irreversible changes in composition and structure of polymers molecules. As a result of these reactions, mechanical, electrical and/or aesthetic properties are degraded beyond acceptable limits. It is now generally recognized that stabilization against degradation is necessary if the useful life of polymers is to be extended sufficiently to meet design requirements for long-term applications. Polymers degrade by a wide variety of mechanisms, several of which affect all polymers through to varying degree. This monograph will concentrate on those degradation mechanisms which result from reactions of polymers with oxygen in its various forms and which are accelerated by heat and/or radiation. Those stabilization mechanisms are discussed which are based on an understanding of degradation reaction mechanisms that are reasonably well established. The stabilization of polymers is still undergoing a transition from an art to a science as mechanisms of degradation become more fully developed. A scientific approach to stabilization can only be approached when there is an understanding of the reactions that lead to degradation. Stabilization against biodegradation and burning will not be discussed since there is not a clear understanding of how polymers degrade under these conditions.

The first edition of this book had been written with the special aim to provide the necessary information for an understanding of the deformation and scission of chain molecules and its role in polymer fracture. In this field there had been an intense ac­ tivity in the sixties and early seventies. The new results from spectroscopical (ESR, IR) and fracture mechanics methods reported in the first edition had complemented in a very successful way the conventional interpretations of fracture behavior. The extremely friendly reception of this book by the polymer community has shown that the subject was timely chosen and that the treatment had satisfied a need. In view of the importance of a molecular interpretation of fracture phenomena and of the continued demand for this book which still is the only one of its kind, a second edition has become necessary. The aims of the second edition will be similar to those of the first: it will be at­ tempted to reference and evaluate completely the literature on stress-induced chain scission, now up to 1985/86. References on other subjects such as morphology, vis­ coelasticity, plastiC deformation and fracture mechanics, where the treatment was never meant to be exhaustive, have remained selective, but they have been updated.

Polymer composites represent a field of intense and growing interest to consumers and producers of plastics. They are used to solve the most acute problems: energy and oil conservation, improvement of the properties of polymer materials, and the increase of their use. Even special problems, such as inflammability of plastics and industrial wastes, are closely connected with polymer composites. The achievements in this field are well known. Polymer composites have been widely used in building, furniture, electric appliances, cars, and other fields. Their production is growing at a higher rate than that of polymers as a whole. In the present book the emphasis is put on the principles that may become the foundation of designing new highly effective composites. The authors analyze their favorable properties as compared to "unfilled" polymers, as well as the means to improve moldability and strength. Economical and technical problems are examined. Special attention is paid to the matching of the components, development of technological processes of composites production, and to new ideas in the field. Fundamental and practical aspects of calculating properties and structure of composites are examined. The scope of the book does not include composites based on continuous reinforcing fibers, polymeric concretes, nor other special-purpose materials in which polymers are used to modify the properties of inorganic materials. The book reflects mainly ideas developed at the Institute of Chemical Physics of the USSR Academy of Sciences, but it also contains a review of the latest works in the field.

The increasing use of advanced composite materials in modem structures of high performance calls for a detailed knowledge of their properties. On the other hand, these materials possessing intense anisotropy, and in some cases non homogeneity, require complicated theories based on homogeneous anisotropic elasticity. Typically, such materials either involve fiber-reinforced composites, which are stacked in layers and form laminates, or particulate composites, containing a second phase in powder form. However, each case must be separately analyzed in terms of the particular characteristics of the materials involved and the process of preparation of the com­ posite systems. Composite materials consisting of more than one destinct phase are in general use in modem industrial applications. Machine parts, structural components and others may be manufactured from such materials. Epoxy resins are suitable matrices for this class of materials. This is due not only to their general-properties such as linear mechanical behavior, transparency, etc., but also to the possibility of modifying their mechanical and optical properties in a very wide range by using suitable modifiers. Their rheological behavior, as well as their dynamic properties have been extensively investigated.

The concept of controlled release has attracted increasing attention over the last two decades, with the applications of this technology proliferating in diverse fields in­ cluding medicine, agriculture and biotechnology. Research and developmental efforts related to controlled release are multiplying in both industry and academia. The reason for this phenomenal growth is obvious. The use of a variety of biologically active agents, such as drugs, fertilizers and pesticides, has become an integral part of modern society. Along with the use of these reagents has evolved an awareness that their uncontrolled application almost inevitably induces harmful effects on the health of humans and their surrounding environments. To eliminate or minimize these harmful effects necessitates the controlled release of these chemicals. Moreover, the controlled release of substances, not usually considered toxic or hazardous, e.g., some catalysts and nutrients, can enhance their effectiveness. The numberand variety of controlled release systems, differing in their physical and chemical makeup, are increasing rapidly. Proliferation almost always demands correlation, generalization and unification; it requires both the development of underlying theories of their behavior and the mechanistic interpretation of their performance. This, in turn, requires a statistical and mathematical (quantitative) treatment of the scientific information and technical data pertaining to them. A quantitative treatment can also facilitate the formulation of procedures for computer-aided design of these systems through a priori prediction of their per­ formance for a variety of design parameters.