Polymer Degradation and Stabilization

Polymer Degradation and Stabilization PDF Author: W. L. Hawkins
Publisher: Springer Science & Business Media
ISBN: 3642693768
Category : Technology & Engineering
Languages : en
Pages : 129

Get Book Here

Book Description
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.

Polymer Degradation and Stabilization

Polymer Degradation and Stabilization PDF Author: W. L. Hawkins
Publisher: Springer Science & Business Media
ISBN: 3642693768
Category : Technology & Engineering
Languages : en
Pages : 129

Get Book Here

Book Description
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.

Mechanisms of Polymer Degradation and Stabilisation

Mechanisms of Polymer Degradation and Stabilisation PDF Author: G. Scott
Publisher: Springer Science & Business Media
ISBN: 9401138389
Category : Technology & Engineering
Languages : en
Pages : 336

Get Book Here

Book Description
The purpose of this publication is two-fold. In the first place it is intended to review progress in the development of practical stabilising systems for a wide range of polymers and applications. A complemen tary and ultimately more important objective is to accommodate these practical developments within the framework of antioxidant theory, since there can be little question that further major advances in the practice of stabilisation technology will only be possible on a firm mechanistic foundation. With the continual increase in the number of commercial anti oxidants and stabilisers, often functioning by mechanisms not even considered ten years ago, there is a need for a general theory which will allow the potential user to predict the performance of a particular antioxidant structure under specific practical conditions. Any such predictive tool must involve a simplified kinetic approach to inhibited oxidation and, in Chapter 1, Denisov outlines a possible mechanistic approach with the potential to predict the most useful antioxidant to use and the limits of its usefulness. In Chapter 2, Schwetlick reviews the current state of knowledge on the antioxidant mechanisms of the phosphite esters with particular emphasis on their catalytic peroxidolytic activity. Dithiophosphate v vi PREFACE derivatives show a similar behaviour but for quite different reasons and, in Chapter 3, AI-Malaika reviews information available from analytical studies, particularly using 31p_NMR spectroscopy, to elucid ate the complex chemistry that leads to the formation of the antioxidant -active agents.

Polymer Photodegradation

Polymer Photodegradation PDF Author: J.F. Rabek
Publisher: Springer Science & Business Media
ISBN: 9401112746
Category : Technology & Engineering
Languages : en
Pages : 679

Get Book Here

Book Description
During the last two decades, the production of polymers and plastics has been increasing rapidly. In spite of developing new polymers and polymeric materials, only 40~60 are used commercially on a large scale. It has been estimated that half of the annual production of polymers is employed outdoors. The photochemical instability of most polymers limits their outdoor application as they are photodegraded quickly over periods from months to a few years. To the despair of technologists and consumers alike, photodegradation and environmental ageing of polymers occur much faster than can be expected from knowledge collected in laboratories. In order to improve polymer photostability there has been a very big effort during the last 30 years to understand the mechanisms involved in photodegradation and environmental ageing. This book represents the author's attempt, based on his 25 years' experience in research on photodegradation and photo stabilization, to collect and generalize a number of available data on the photodegradation of polymers. The space limitation and the tremendous number of publications in the past two decades have made a detailed presentation of all important results and data difficult. The author apologizes to those whose work has not been quoted or widely presented in this book. Because many published results are very often contradictory, it has been difficult to present a fully critical review of collected knowledge, without antagonizing authors. For that reason, all available theories, mechanisms and different suggestions have been presented together, and only practice can evaluate which of them are valid.

Thermal Degradation of Polymeric Materials

Thermal Degradation of Polymeric Materials PDF Author: Krzysztof Pielichowski
Publisher: iSmithers Rapra Publishing
ISBN: 9781859574980
Category : Science
Languages : en
Pages : 324

Get Book Here

Book Description
Understanding the thermal degradation of polymers is of paramount importance for developing a rational technology of polymer processing and higher-temperature applications. Controlling degradation requires understanding of many different phenomena, including chemical mechanisms, the influence of polymer morphology, the complexities of oxidation chemistry, and the effects of stabilisers, fillers and other additives. This book offers a wealth of information for polymer researchers and processors requiring an understanding of the implications of thermal degradation on material and product performance.

Polymer Degradation and Stabilisation

Polymer Degradation and Stabilisation PDF Author: Norman Grassie
Publisher: CUP Archive
ISBN: 9780521357975
Category : Science
Languages : en
Pages : 236

Get Book Here

Book Description
The study of polymer degradation and stabilisation is of considerable practical importance as the industrial uses of polymeric materials continue to expand. In this book, the authors lucidly relate technological phenomena to the chemistry and physics of degradation and stabilisation processes. Degradation embraces a variety of technologically important phenomena ranging from relatively low temperature processes such as 'weathering' of plastics, 'fatigue' of rubbers through the processing of polymers in shearing mixers to very high temperature processes such as flammability and ablation. All these technological phenomena have in common certain basic chemical reactions. Thus 'weathering' has its roots in photo-oxidation, 'fatigue' and melt-degradation in mechano-oxidation and flammability, and ablation in ablation in pyrolysis and vapour phase oxidation.

Photodegradation of Polymers

Photodegradation of Polymers PDF Author: Jan F. Rabek
Publisher: Springer Science & Business Media
ISBN: 3642800904
Category : Science
Languages : en
Pages : 222

Get Book Here

Book Description
In this book on physical characteristics and practical aspects of polymer photodegradation Rabek emphasizes the experimental work on the subject. The most important feature of the book is the physical interpretation of polymer degradation, e.g. mechanism of UV/light absorption, formation of excited states, energy transfer mechanism, kinetics, dependence on physical properties of macromolecules and polymer matrices, formation of mechanical defects, practics during environmental ageing. He includes also some aspects of polymer photodegradation in environmental and space condition.

Analytical Pyrolysis Handbook

Analytical Pyrolysis Handbook PDF Author: Karen D. Sam
Publisher: CRC Press
ISBN: 0429577036
Category : Science
Languages : en
Pages : 327

Get Book Here

Book Description
Analytical pyrolysis allows scientists to use routine laboratory instrumentation for analyzing complex, opaque, or insoluble samples more effectively than other analytical techniques alone. Analytical Pyrolysis Handbook, Third Edition is a practical guide to the application of pyrolysis techniques to various samples and sample types for a diversity of fields including microbiology, forensic science, industrial research, and environmental analysis. The much-anticipated third edition incorporates recent technological advances that increase the technique’s sensitivity to trace elements, improve its reproducibility, and expand its applicability. The book reviews the types of instrumentation available to perform pyrolysis and offers guidance for interfacing instruments and integrating other analytical techniques, including gas chromatography and mass spectrometry. Fully updated with new sample pyrograms, figures, references, and real-world examples, this edition also highlights new areas of application including cultural materials, forensic analysis, and environmental studies. This book illustrates how the latest advances make pyrolysis a practical, cost-effective, reliable, and flexible alternative for increasingly complex sample analyses. Analytical Pyrolysis Handbook, Third Edition is an essential, one-stop guide for determining if pyrolysis meets application-specific needs as well as performing pyrolysis and handling the data obtained.

Electrical Degradation and Breakdown in Polymers

Electrical Degradation and Breakdown in Polymers PDF Author: Len A. Dissado
Publisher: IET
ISBN: 9780863411960
Category : Science
Languages : en
Pages : 630

Get Book Here

Book Description
The book is in five parts: Part I introduces the physical and chemical structure of polymers and their breakdown; Part II reviews electrical degradation in polymers, and Part III reviews conduction and deterministic breakdown in solids. Part IV discusses the stochastic nature of break-down from empirical and modelling viewpoints, and Part V indicates practical implications and strategies for engineers. Much of the discussion applies to non-crystalline materials generally.

Polymer Degradation Mechanisms

Polymer Degradation Mechanisms PDF Author: United States. National Bureau of Standards
Publisher:
ISBN:
Category : Polymerization
Languages : en
Pages : 288

Get Book Here

Book Description


Reactions and Mechanisms in Thermal Analysis of Advanced Materials

Reactions and Mechanisms in Thermal Analysis of Advanced Materials PDF Author: Atul Tiwari
Publisher: John Wiley & Sons
ISBN: 1119117704
Category : Technology & Engineering
Languages : en
Pages : 660

Get Book Here

Book Description
Strong bonds form stronger materials. For this reason, the investigation on thermal degradation of materials is a significantly important area in research and development activities. The analysis of thermal stability can be used to assess the behavior of materials in the aggressive environmental conditions, which in turn provides valuable information about the service life span of the materiel. Unlike other books published so far that have focused on either the fundamentals of thermal analysis or the degradation pattern of the materials, this book is specifically on the mechanism of degradation of materials. The mechanism of rapturing of chemical bonds as a result of exposure to high-temperature environment is difficult to study and resulting mechanistic pathway hard to establish. Limited information is available on this subject in the published literatures and difficult to excavate. Chapters in this book are contributed by the experts working on thermal degradation and analysis of the wide variety of advanced and traditional materials. Each chapter discusses the material, its possible application, behavior of chemical entities when exposed to high-temperature environment and mode and the mechanistic route of its decomposition. Such information is crucial while selecting the chemical ingredients during the synthesis or development of new materials technology.