The effects of thermal treatment after radiation on microstructure and physical property of polypropylene(PP) were investigated. Isotactic PP(i-PP) was selected as the polymer matrix in this work. The PP sheets were prepared by pressing into a lmm sheet at 200°C. Co60 gamma-ray irradiation was conducted at 25kGy in nitrogen. Following the irradiation, the PP sheet was thermal-treated at various temperature to remove the remaining the radicals. The microstructure of i-PP such as crystalline phase, before and after thermal treatmernt after irradiation was evaluated by WAXD(wide angle x-ray diffraction). The crys-tallinity of the samples was evaluated, by differential scanning calorimetry(DSC), from the heat of fusion relative to a value of 209 J/g corresponding to a 100% crystalline PP. Thermal property of the i-PP after irradiation was also analysed by DSC. Tensile property of these irradiated specimens have been investigated as well.
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