Affiliation: | a Takasaki Radiation Chemistry Research Establishment, Japan Atomic Energy Research Institute, Watanuki-machi, Takasaki-shi, Gunma-ken 370-12, Japan b Center for the Applications of Isotopes and Radiation, National Atomic Energy Agency JL. Cinere Pasar Jumat PO Box 7002, JKSL, Jakarta 12070, Indonesia c Center for Nuclear Techniques, 217 Nguyen Trai St., District 1, HCMC, Vietnam d Graduate School of Engineering, Kyoto University, Yoshida Hon-cho, Sakyo-ku, Kyoto 606-01, Japan |
Abstract: | A compatibilizer is normally added to enhance the compatibility during blending of two polymers. Polypropylene (PP) has two degradations, during irradiation and also during storage after irradiation in radiation sterilization. A compatibilizer was added to PP to reduce these degradations. Compatibilizers, such as hydrogenated styrene (10 mol%)/butadiene rubber (CPB-2) and ethylene/propylene rubber grafted with maleic anhydride, were found to retard remarkably the above-mentioned degradations of PP. The compatibilizer concentration required for enhancing the radiation resistance of PP depends on the radiation resistance before addition of the compatibilizer. Poor radiation-resistant PP of a lower molecular weight (Melt flow index, 10) required a higher concentration, above 10% of CPB-2 to impart radiation resistance, but high-molecular-weight PP (Melt flow index, 1.0) and copolypropylene (CPP) with an ethylene content of 2.5% required CPB-2 of 5% and 10% to induce sufficient radiation resistance. Furthermore, CPB-2 was effective for improvement of transparency besides its contribution to radiation resistance of PP. The CPB-2 lead to lower crystallinity to retard the crystallization of PP and CPP and also may result in a mixed monoclinic and smectic structure giving radiation resistance. |