Durability of Radiaton-Sterilized Polymers : IV Effect of depth of the Oxidative Layer on Degradation During Irradiation

Abstract

In relation to sterilization of medical devices, polypropylene film of various thickness (100-1000 μm) were irradiated with electron beam or γ-rays and effect of depth of the oxidative layer evaluated with chemiluminescence on the degree of deterioration (decrease in molecular weight and elongation at break) has been investigated. Upon irradiation thinner films degraded extremely due to the oxidation in the interior portion of sample as well as surface. On the countrary, the degradation was less for thicker samples. Deterioration by irradiation was more remarkable with decreasing dose rate owing to increase in the depth of oxidative layer, indicating preference irradiation in a shorter period under a higher dose rate.