Mechanisms of Polymer Degradation and Stabilisation

Author: G. Scott
Publisher: Springer Science & Business Media
ISBN: 9401138389
Format: PDF, ePub
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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.

Fundamentals of Polymer Degradation and Stabilization

Author: N.S. Allen
Publisher: Springer Science & Business Media
ISBN: 9781851667734
Format: PDF
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During the past decade, the field of polymer degradation and stabilization has become a subject of central importance in polymer science and technology. This book provides a fundamental source of information designed for those with only a basic understanding of the background of the field.

Polymer Degradation and Stabilization

Author: W. L. Hawkins
Publisher: Springer Science & Business Media
ISBN: 3642693768
Format: PDF, Kindle
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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 Stabilisation

Author: Norman Grassie
Publisher: CUP Archive
ISBN: 9780521357975
Format: PDF, Mobi
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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.

The Chemistry of Membranes Used in Fuel Cells

Author: Shulamith Schlick
Publisher: John Wiley & Sons
ISBN: 1119196051
Format: PDF
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The evolution of fuel cells and their components -- Degradation mechanism of perfluorinated membranes -- Ranking the stability of perfluorinated membranes to attack by hydroxyl radicals -- Stabilization of perfluorinated membranes using Ce3+ and Mn2+ redox scavengers: mechanism and applications -- Hydrocarbon proton exchange membranes -- Stabilization of perfluorinated membranes using nanoparticle additives -- Degradation mechanism in aquivion perfluorinated membranes and stabilization strategies -- Anion exchange membrane: stability and synthetic approach -- Profiling of membrane degradation processes in a fuel cell by 2D spectral-spatial FTIR-- Quantum mechanical calculation of the degradation in perfluorinated membranes used in fuel cells

Handbook of Polymer Degradation Second Edition

Author: S. Halim Hamid
Publisher: CRC Press
ISBN: 1482270188
Format: PDF, ePub, Mobi
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"Covers recent advances in polymer degradation and stabilization. Focuses on the basics of photo- and bio-degradability. Delineates special and general environmental parameters such as solar irradiation, temperature, and agrochemical exposure. Surveys plastic waste disposal strategies such as recycling, incineration, chemical recovery by pyrolysis, and source reduction."

Polymer durability

Author: Roger Lee Clough
Publisher: An American Chemical Society Publication
ISBN: 9780841231344
Format: PDF
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Provides a comprehensive overview of the science of polymer durability. Discusses the molecular mechanisms of polymer aging and deterioration, emphasizing UV and thermal exposure environments. Describes a variety of analytical techniques for studying degradation, with special emphasis on chemiluminescence. Covers advances in the use of additives and other approaches for enhancing polymer stability. Reviews mechanisms and applications of major classes of stabilizers, and discusses the problem of stabilizer migration and loss. Examines new methods for predicting the aging rate and lifetime of a material.

Polymer Photodegradation

Author: Jan F. RABEK
Publisher: Springer Science & Business Media
ISBN: 9401112746
Format: PDF, Mobi
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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.