Deterioration of Organic Polymers

This paper is a general review of deterioration processes in polymers. It is pointed out that changes in properties with aging are usually the result of chemical reaction with components of the atmosphere. The mechanisms of these reactions and some methods of preventing or retarding them are discussed. / ^ R G A N I C compounds which have enough inherent strength to be used as structural materials--e.g. rubbers, plastics, textiles, and surface coatings--belong to a class called polymers. The deterioration of these materials in service is a serious problem, probably equal in dollar value to corrosion of metals, and one or another aspect of it has been under study in the Laboratories for years. 1 Everyone is familiar with the tendering of cotton cloth and with the loss of strength of rubber with time, but except among people who work with them there is not a wide recognition of the fact that plastics also suffer extensive damage from the weather. This is probably because organic corrosion is usually not visible in its early stages even though deep-seated changes may be taking place throughout the body of the material. In its advanced state, however, such deterioration is easily observable, manifesting itself in loss of strength, erosion, warpage, development of cracks, loss of transparency, or in other ways depending on the material and the application. These changes are of obvious importance in most engineering uses, particularly in the Bell System where apparatus frequently is expected to last thirty or forty years, and it is therefore desirable that they be understood.