Radiation-induced oxidation of plastics

Radiation-induced oxidation of polymers is reviewed, focusing on fundamental free radical aspects, degradation, along with changes in molecular structure and mechanical properties. Postirradiation oxidation involving carbon-centered free radicals, as well as kinetics, have been investigated by electron spin resonance methods. Oxygen diffusion into plastics plays an important role in the oxidation process. The relation between the polymer radical reactions and molecular motion has been determined by studying the peroxy radicals trapped in polypropylene. Oxygen uptake, analyses of oxidation products, effects of irradiation conditions, and the protection offered by antioxidants and antirad agents are also reviewed. (orig.)