Photodegradation of Polymers: Physical Characteristics and Applications

ISBN-13: 9783642800924 / Angielski / Miękka / 2011 / 212 str.

Jan F. Rabek

Opis

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.

Spis treści

1 Absorption of Radiation.- 1.1 Radiation and Its Energy.- 1.2 SI Units Used in Photochemistry.- 1.3 Absorption Cross Section.- 1.4 Practical Aspects of the Lambert-Beer Equation.- 2 Electronically Excited States in Polymers.- 2.1 Formation of Excited States.- 2.2 Radiative Processes.- 2.3 Radiationless Transitions.- 2.4 Excitation of Chromophores.- 2.5 Luminescence Emission from Chromophores.- 2.6 Kinetics of Photophysical Processes.- 2.7 Quenching Processes of Excited States.- 2.8 Quenching Processes in Solution.- 2.9 Quenching Processes in Polymer Matrices.- 3 Electronic Energy Transfer Processes in Polymers.- 3.1 Energy Transfer in Photodegradation Processes.- 3.2 Physical Aspects of Electronic Energy Transfer.- 3.3 Radiative Energy Transfer.- 3.4 Electron Exchange Energy Transfer.- 3.5 Resonance Excitation Energy Transfer.- 3.6 Efficiency of Energy Transfer.- 3.7 Spectroscopic Overlap Integral.- 3.8 Energy Transfer Processes in Solution.- 3.9 Diffusion-Controlled Reactions.- 3.10 Solvent Effects.- 3.11 Viscosity Effects.- 3.12 Energy Transfer in Rigid Polymer Matrix.- 3.13 Spectroscopic Methods for the Determination of Electronic Energy Transfer Processes.- 3.14 Singlet—Singlet Energy Transfer in Polymers.- 3.15 Triplet—Triplet Energy Transfer in Polymers.- 3.16 Energy Transfer from Carbonyl Groups to Hydroperoxides..- 3.17 Energy Transfer from Phenyl Group to Hydroperoxides.- 3.18 Excited State Annihilation Processes.- 3.19 Energy Migration in Polymers.- 3.20 Energy Migration in Excimer-Forming Polymers.- 4 Photo-Oxidative Degradation.- 4.1 Introduction to Photochemical Reactions in Polymers.- 4.2 Photochemical Laws.- 4.3 Photochemical Activation.- 4.4 Photodissociation of a Molecule.- 4.5 Quantum Yields of Photodegradation.- 4.6 Absorption of Radiation by Polymers.- 4.7 Formation of UV/Light Absorbing Impurities.- 4.8 Photoinitiation of Polymer Degradation.- 4.9 General Mechanism of Polymer Photo-Oxidative Degradation.- 4.10 Chain Propagation.- 4.11 Photochain-Oxidation Reaction.- 4.12 Main Chain Scission.- 4.13 Chain Branching.- 4.14 Termination Reaction.- 4.15 Dark Processes in Photodegradation of Polymers.- 4.16 Hydrogen Atom Abstraction.- 4.17 Formation of Hydroxy and/or Hydroperoxy Groups.- 4.18 Homolytic Decomposition of Hydroperoxides.- 4.19 Photodecomposition of Hydroperoxide Groups.- 4.20 Reactions of Hydroxy (HO·) and Hydroperoxy (HO2·) Radicals with Polymers.- 4.21 Formation of Carbonyl Groups.- 4.22 Formation of Carboxylic and Per-Carboxylic Groups.- 4.23 Norrish Type I and Type II Reactions.- 4.24 Formation of ?, ?-Unsaturated Carbonyl Groups.- 4.25 Conversion of Polymeric Free Radicals Under UV/Visible Radiation and Warming.- 4.26 Photodegradation of Chlorinated Polymers.- 4.27 Phenyl Ring-Opening Photo-Reactions.- 4.28 PhotoFries Rearrangement in Polymers.- 4.29 Photo-Oxygenation of Polymers by Singlet Oxygen.- 4.30 Photoinitiated Degradation of Polymers.- 4.31 Photoinitiated Degradation of Polymers by Dyes.- 4.32 Photoinduced Electron Transfer.- 5 Physical Factors Which Influence Photodegradation.- 5.1 Effect of Free Volume.- 5.2 Effect of the Glass Transition Temperature.- 5.3 Effect of Crystallinity.- 5.4 Localization of the Oxidation Processes in Semicrystalline Polymers.- 5.5 Chemicrystallization Process.- 5.6 Effect of Polymer Molecular Weight.- 5.7 Effect of the Formation of Hydrogen Bonds.- 5.8 Cage Recombination.- 6 Kinetic Treatments of Degradation.- 6.1 Photodegradation in Isothermal and Non-Isothermal Conditions.- 6.2 Decay of Free Radicals in a Polymer Matrix.- 6.3 Spin Trapping of Polymeric Radicals.- 6.4 Photodepolymerization.- 6.5 Kinetics of Photodegradation.- 6.6 Number of Main Chain Scissions.- 6.7 Quantum Yield of Chain Scission.- 6.8 Quantum Yield of Crosslinking.- 6.9 Principles Governing the Changes in Molecular Weight and Molecular Weight Distribution During Polymer Photodegradation.- 6.10 Reaction Kinetics of Polymer Photo-Oxidation.- 6.11 Diffusion Controlled Oxidation of Polymers.- 6.12 Oxidation Profiles.- 7 Photodegradation of Solid Polymers.- 7.1 Differences Between Photodegradation of Polymers in Solid and Liquid Phases.- 7.2 Polymer Mechanical Properties Affected by Degradation.- 7.3 Role of Water in the Degradation Processes.- 7.4 Effect of Orientation on Degradation.- 7.5 Degradation of Polymers Under Deformation Forces.- 7.6 Feedback in Polymer Degradation.- 7.7 Stress-Accelerated Photo-Oxidation of Polymers.- 7.8 Photodegradation of Polymers for Solar Energy Devices.- 8 Photodecomposition of Polymers by Laser Radiation.- 8.1 Ablative Photodecomposition of Polymers.- 8.2 Photokinetic Etching.- 8.3 Thermal Processing of Polymers by Visible and Infrared Laser Radiation.- 9 Practical Aspects of Polymer Photodegradation.- 9.1 Photodegradation of Polymers Under Weathering Conditions.- 9.2 Photodegradation of Polymers in Natural Waters.- 9.3 Photodegradation of Polymers Under Marine Exposure Conditions.- 9.4 Hydrolysis Processes During Ageing of Polymers.- 9.5 Plastic Ecological Problems.- 9.6 Photodegradable Polymers with Controlled Lifetimes.- 9.7 Ecolyte Plastics.- 9.8 Plastic Protective Films.- 9.9 Recovery of Photodegraded Polymers.- 9.10 Photodegradation of Polymers in the Polluted Atmosphere.- 9.11 Photodegradation of Polymers in the Stratosphere.- 9.12 Photodegradation of Polymers in Space.- 9.13 Atomic Oxygen Reactions with Polymers.- 9.14 Polymeric Photoinitiators Operating with a Fragmentation Mechanism.- 9.15 Positive-Working Photo resists.- 10 References.

O autorze

The greatest benefit of this book is that it covers for the first time the latest development relating polymer degradation with physical processes. Experiments are collected and the practical aspects are shown. This book is of interest to all engineers and scientists in industry and universities working in polymer and materials science or in physics in the field of photodegradation.