Crosslinking of Polymers by Radiation

Abstract

Early work showed that many polymers become crosslinked following exposure to high energy radiation – typically high energy electrons or gammas. Subsequent research has sought to answer a number of basic questions on radiation mechanisms. At the same time applications have been sought successfully in a range of specialist materials.
One of the great advantages of radiation treatment is that it enables useful chemical reactions to be initiated in the solid state. The precise mechanisms involved are still not generally agreed, but appear to depend largely on the interaction of radicals which, to promote crosslinking, must be mobile. A series of reactions occur between the initial absorption of radiation and the final chemical change, and it is possible to intervene in several of these stages to modify the final product. This type of study shows considerable relevance to the problems investigated in radiobiology. Other aspects of importance are the crosslinking of polymers in solution, the radiation treatment of single crystals of polymer, and the use of additives for reinforcement.
After an initial period, radiation processing has become an established industrial procedure, aided largely by the rapidly reducing cost of high energy radiation. Its wider use must be largely determined by the discovery of new applications in which its unique advantages can be fully utilised.