Aging and Stabilization of Polymers

The need for a broad development of the production of polymer ma- terials has become evident. All these materials are subject to various types of aging (destruction); hence, stabilizers which permit the stor- age, reprocessing, and use of polymer materials without any appreci- able change in their properties must be introduced into them. In recent years, this problem of stabilizing polymers has attracted the attention of many scientists and technologists, both in the USSR and abroad. The scientific basis of the foreign studies will be found in a number of theo- retical premises, but chiefly the theory of chain reactions with un- branched chains. In the Soviet Union, the concepts of Academician N. N. Semenov on chain reactions with degenerate branches have become the starting point of theoretical studies of the stabilization and destruction of polymers. Soviet scientists have developed a theory of critical concentrations of antioxidants and have shown that the processes of stabilization have a very complex chemical character. The nature of the polymers them- selves greatly affects these processes and consequently, different stabil- izers are required for polymers of different structures. In addition, it has been shown that the antioxidants used thus far can not only cause chain termination, but can also initiate oxidation and give rise to de- generate branches.

Table of Contents:
Introduction: Significance and Prospects of the Stabilization of Polymers and Articles Made from Them.- I. Mechanism of the Thermooxidative Destruction and Stabilization of Polymers.- 1. Oxidation in the Gas and Liquid Phases.- 2. Oxidation in the Solid Phase.- 3. Oxidation in Polypropylene.- 4. Autoinhibition of the Oxidation of Polymers.- 5. Critical Concentration of Antioxidants.- 6. Initiation of Oxidation by Antioxidants.- 7. Theory of Synergism.- 8. Free Radicals as Stabilizers.- 9. Boric Stabilizers.- II. Stable Radicals of Inhibitors of Oxidative Processes.- 1. Phenoxyl Radicals.- 2. Stable Radicals of Naphthols.- 3. Stable Radicals of Aromatic Amines.- 4. Formation of Stable Radicals of Inhibitions During Oxidation Processes.- III. Synthesis of Stabilizers for Polymer Materials.- I. Photostabilizers.- II. Antioxidants.- IV. Aging and Stabilization of Polyolefins.- I. Oxidative Destruction of Polyolefins.- II. Stabilization of Polyolefins Against Oxidative Destruction.- III. Destruction of Polyolefins Under the Action of Light.- IV. Increasing the Light Stability of Polyolefins.- V. Aging and Stabilization of Polyformaldehyde.- 1. Thermal and Thermooxidative Destruction.- 2. Stabilization of Polyformaldehyde.- 3. Bonding of Formaldehyde by Polyamides.- 4. Inhibition of the Process of Oxidation of Polyformaldehyde by Inhibitors, Derivatives of Aromatic Amines and Phenols, Phosphites, and Sulfur-Containing Compounds.- 5. Inhibition of the Oxidation of Polyformaldehyde by Radical-Type Inhibitors.- 6. Consumption of Nitrogen Oxide Stable Radicals in the Thermal Oxidation of Polyformaldehyde.- VI. Aging and Stabilization of Polyvinyl Chloride and Copolymers of Vinyl Chloride.- I. Factors Determining the Mechanism and Rate of Decomposition of Polyvinyl Chloride.- II. General Principles of the Stabilization of Polyvinyl Chloride.- III. Methods of Evaluating the Effectiveness of the of the Action of Polyvinyl Chloride Stabilizers.- IV. Stabilizers of Polyvinyl Chloride and Vinyl Chloride Copolymers.- VII. Aging and Stabilization of Polyamides.- I. Thermal Aging of Polyamides.- II. Thermal Oxidation of Polyamides.- III. Stabilization of Polyamides Against Thermal Oxidation.- IV. Photoaging of Polyamides.- V. Photostabilization of Polyamides.- VIII. Aging of Certain Condensation Polymers.- I. Epoxide Resins.- II. Phenol-Formaldehyde Resins.- III. Polyarylates.- IV. Polycarbonate.- IX. Aging of Polymers with Inorganic Principal.- Chains of the Molecules, Framed by Organic Groups.- X. Aging and Stabilization of Raw and Cured Rubbers.- I. Thermal Oxidation of Raw Rubbers in the Presence of Inhibitors.- II. Thermal Oxidation of Cured Rubbers.- III. Light Aging.- IV. Aging of Raw Rubbers at High Temperatures.- V. Corrosion Cracking of Cured Rubbers.- VI. Aging of Polymers Under the Action of Ionizing Radiations.- VII. Influence of Mechanical Stresses on the Aging of Cured Rubbers.- XI. Mechanochemical Processes in Highly Elastic Polymers.- I. Cleavage of the Macromolecule.- II. Mechanochemical Phenomena in the Case of Repeated Deformation of Highly Elastic Polymers.- III. Mechanochemical Phenomena in the Reprocessing of Highly Elastic Polymers.