Polypropylene Response to High-Energy Radiation

Abstract

This chapter discusses that normal polypropylene will become highly embrittled following sterilizing doses of high-energy irradiation. This embrittlement becomes progressively severe with post-irradiation time and temperature. The basic mechanism involved is oxidative which is initiated by the radicals formed during the irradiation process. There are several factors involved in preventing or minimizing these degradative effects. The need for materials that will withstand ionizing radiation during sterilization of medical products has increased dramatically due to regulatory problems associated with ethylene oxide residuals found after ethylene oxide sterilization. As a consequence, the need for better stabilization packages that can tolerate a sterilizing dose of25 kGy has increased along with the requirement to understand the mechanism of why a plastic embrittles or discolors during irradiation. The chapter also analyzes polypropylene that readily degrades during irradiation. It provides a mechanistic example along with experimental results to support the theory of polymer stabilization by different approaches.