γ辐照LDPE/EPDM共混物的动态力学性能和热行为

Dynamic mechanical properties and thermal behavior of gamma-irradiated LDPE/EPDM blends

本文报道了^(60)Coγ辐照LDPE/EPDM共混物的动态力学性能和热行为。在动态力学性能谱上出现两个转变,-20℃左右的转变是LDPE的β转变和EPDM玻璃化转变相叠加的转变,其峰温简称T_(βg),转变峰较平坦,表明LDPE/EPDM具有一定相容性;在69℃附近的另一个转变是LDPE的结晶预熔温度,随辐照剂量的增加而下降。未辐照的α转变活化能为106kJ/mol,辐照后活化能下降至80kJ/mol左右。用DSC法在所利用的剂量范围内,EPDM的T_g随剂量变化甚微,共混物的T_(βg)则不明显。LDPE的T_m辐照后有所下降,结晶度略有改变。

The dynamic mechanical properties and thermal behavior of gamma radiation crosslinked LDPE/EPDM blends have been investigated over a temperature range from -50 to 100℃ and-70 to 150℃respectively. The results show that there is a damped peak (tanδmax) of about -20℃ in the dynamic mechanical spectra, and the peak temperature is denoted as Tβg, but the damped peak in low temperature region for each of LDPE and EPDM in blends disappeared. After irradiation, the Tβg of the LDPE/EPDM blends still appeared on the spectra, and gamma radiation does not affected the compatibility of LDPE and EPDM. The thermal analysis results reveal that the fusion temperature Tm of irradiated LDPE/EPDM systems decreases with the increase of radiation doses.