Durability of radiation‐sterilized polymers. I. Estimation of oxidative degradation in polymers by chemiluminescence

Abstract

In relation to sterilization of medical supplies, the degree of degradation by γ‐ray and electron beam irradiations of homopolypropylene (HP), copolypropylene (CP, coplymer including 6% of ethylene unit) and polymethylpentene were compared, and chemiluminescence (CL) of irradiated polymers were measured. HP degraded extremely around the sterilization dose (2.5 Mrad) by either γ‐ray or electron beam irradiations. In the case of CP and polymethylpentene, stabilities of polymers far differed between γ‐ray and electron beam irradiations. The polymethylpentene was more stable than the polypropylenes against irradiation. The counts of CL emitted by recombination of peroxy radical (ROO ·) increased with increasing dose, reflecting degrees of oxidation of polymers. The degradation of polymers was independent of irradiation sources, rather it depended on the degree of oxidation. It was found that CL analysis are favorable for estimation of degradation in irradiated polymers.