Low Temperature Properties Of Polymers

Low-Temperature Properties of Polymers systematizes the available materials on polymers. This book also describes the main trends in the investigation of interrelated properties of polymers, such as thermal (heat capacity, thermal conductivity, and thermal expansion), acoustical, dielectric, and viscoelastic, which maintain the physical properties of polymers at low temperatures. Comprised of nine chapters, this book first covers heat capacity of polymers at low temperature, and then tackles thermal conductivity of polymers at low temperatures. Chapter 3 discusses thermal expansion of polymers at low temperatures, and Chapter 4 tackles electrical properties of polymers at low temperatures. The fifth chapter covers nuclear magnetic resonance in polymers at low temperature, while the succeeding chapter encompasses dynamic mechanical properties of polymers at low temperatures. Chapter 7 concerns itself with the acoustical properties of polymers at low temperatures, while the succeeding chapter covers viscoelastic parameters of polymers at low temperatures. The closing chapter covers how to determine the thermophysical characteristics of polymers by acoustic measurement at helium temperature. This book will be of great interest to researchers or professionals whose line of work involves the manipulation and understanding of the properties of polymers.

Most descriptions of polymers start at room temperature and end at the melting point. This textbook starts at very low temperatures and ends at room temperature. At low temperatures, may processes and relaxations are frozen which allows singular processes or separate relaxations to be studied. At room temperatures, or at the main glass transitions, many processes overlap and the properties are determined by relaxations. At low temperatures, there are temperature ranges with negligible influences by glass transitions. They can be used for investigating so-called basic properties which arise from principles of solid state physics. The chain structure of polymers, however, requires stringent modifications for establishing solid state physics of polymers. Several processes which are specific of polymers, occur only at low temperatures. There are also technological aspects for considering polymers at low temperatures. More and more applications of polymeric materials in low temperature technology appear. Some examples are thermal and electrical insulations, support elements for cryogenic devices, low-loss materials for high frequency equipments. It is hoped that, in addition to the scientific part, a data collection in the appendix may help to apply polymers more intensively in low temperature technology. The author greatly appreciates the contributions by his coworkers of the Kernforschungszentrum Karlsruhe in measurement and discussion of many data presented in the textbook and its appendix. Fruitful disccussions with the colleagues Prof. H. Baur, Prof. S. Hunklinger, Prof. D. Munz and Prof. R.

Kalia and Fu's novel monograph covers cryogenic treatment, properties and applications of cryo-treated polymer materials. Written by numerous international experts, the twelve chapters in this book offer the reader a comprehensive picture of the latest findings and developments, as well as an outlook on the field. Cryogenic technology has seen remarkable progress in the past few years and especially cryogenic properties of polymers are attracting attention through new breakthroughs in space, superconducting, magnetic and electronic techniques. This book is a valuable resource for researchers, educators, engineers and graduate students in the field and at technical institutions.

Cryogenics is an emerging technology filled with promises. Many cryogenic systems demand the use of nonmetallics and composites for adequate or increased performance. Thermal and electrical insulations, potting for superconducting magnets' mechanical sta bility, and composite structures appear to be some of the most significant applications. Research on nonmetallics at cryogenic temperatures has not progressed to the degree of research on metals. Nor can room temperature research be extrapolated to low tempera tures; most polymers undergo a phase transformation to the glassy state below room temperature. Research by producers, for the most part, has not been prac tical, because, except for LNG applications, the market for large material sales is not imminent. There are, however, many government stimulated developmental programs. Research on nonmetallics thus is dictated by development project needs, which require studies orien ted toward prototype hardware and specific objectives. As a result, research continuity suffers. Under these conditions, periodic topical conferences on this subject are needed. Industry and uni versity studies must be encouraged. Designers and project research material specialists need to exchange experiences and data. Low temperature-oriented research groups, such as the National Bureau of Standards and the Institute for Technical Physics - Karlsruhe, must contribute by assisting with fundamentals, interpreting proj ect data, and contributing to project programs through their materials research.

The minimum temperature in the natural universe is 2.7 K. Laboratory refrigerators can reach temperatures in the microkelvin range. Modern industrial refrigerators cool foods at 200 K, whereas space mission payloads must be capable of working at temperatures as low as 20 K. Superconducting magnets used for NMR work at 4.2 K. Hence the properties of materials must be accurately known also at cryogenic temperatures. This book provides a guide for engineers, physicists, chemists, technicians who wish to approach the field of low-temperature material properties. The focus is on the thermal properties and a large spectrum of experimental cases is reported. The book presents updated tables of low-temperature data on materials and a thorough bibliography supplements any further research. Key Features include: ° Detailed technical description of experiments ° Description of the newest cryogenic apparatus ° Offers data on cryogenic properties of the latest new materials ° Current reference review

This book focuses on the effect the composition of rubbers and the conditions of their processing have on low-temperature resistance. It considers the nature and development of two physical processes, glass transition and crystallization, determining low-temperature behavior of elastomers. The book addresses the effects of deformation, pressure, an