【摘要】 用动态粘弹谱仪和DSC研究了聚丙烯/三元乙丙橡胶(PP/EPDM)的动态力学性能,考察了EPDM对PP/LDPE(低密度聚乙烯)的力学行为的影响。结果表明,EPDM对PP有增塑作用,在PP/LDPE/EPDM共混物中,PP和LDPE的非晶部分与EPDM具有部分相容性;PP有两个结晶温度(T_c),较低的一个T_c随共混物中EPDM含量(5～25质量份)的增加逐渐向更低温度区迁移,说明EPDM具有加快冷却速率的作用。更多还原

【Abstract】 The effect of EPDM on the mechanical damping and crystallization behavior of PP/LDPE blends are investigated by means of Rheovibron DDV- Ⅱ EA and Perkin Elmer DSC-2C.The Tg of PP in PP/EPDM blends decreases from 15°C to 5°C when the content of EPDM increases to 80% (mass) (Figure 1). The Tg peaks of LDPE and PP in PP/LDPE/EPDM blends overlap each other and shift to lower temperature side with increasing EPDM content (Figure 2). This phenomenon implies that the amorphous phases are compatible with EPDM . The αc relaxation peaks of both PP and LDPE in PP/LDPE/ EPDM blends overlap reciprocally and become broad sloping band at 30 - 160 °C . The relaxation is crystal premelting transition . The crystallization of PP in PP/EPDM is impeded by EPDM .The EPDM in PP’EPDM and PP/LDPE/EPDM acts as a crystal center . It is shown that the crystalline temperature (Tc) of PP and LDPE in PP/LDPE/EPDM decreases .TwoTc of PP are found in PP/LDPE/EPDM .The lower TC decreases with increasing EPDM content from 5% to 25% (Table).更多还原