Effectiveness of DOP mobilizer on the radiolysis of a semi-crystalline ethylene–propylene copolymer

The role of dioctyl phthalate, DOP, added as a radiation stabilizer (mobilizer) to a commercial, medical grade polypropylene has been examined by FTIR and XPS analyses. It was found that the DOP degraded during γ-irradiation to a sterilization dose under vacuum at 298 K and that the degradation products, which included a variety of oxygenated and aromatic compounds, diffused to the polymer surface.