基体性质对PP/POE共混物力学性能和形态的影响

Effect of Matrix Property on Mechanical Properties and Morphology of PP/POE Blends

采用过氧化二异丙苯(DCP)降解PP/POE共混物。熔体流动速率试验结果表明,当DCP含量从0．2‰(质量分数,下同)增加到1‰时,对应的共混物的熔体流动速率从7．0 g/10 min增加到17．2g/10 min,二者基本成线性关系。并且这种增加(相对分子质量的降低)导致其冲击性能从125 J/m下降到50 J/m；拉伸实验结果表明,共混物相对分子质量的降低对其屈服应力影响不大,这说明相对分子质量的降低主要是引起基体断裂应力的降低,从而导致共混物的冲击强度大大降低；通过扫描电子显微镜观察了不同相对分子质量共混物中橡胶相的分散情况,结果表明,随着DCP含量的增加,共混物中橡胶相的相区尺寸明显增加。因此,共混物冲击强度的降低是基体相对分子质量降低与橡胶相粒径变化共同作用的结果。

The degradation behavior of PP/POE blends caused by DCP was studied. When the content of DCP increased from 0.2 %0 to 1.0 %0, the melt flow rate of the blend increased from 7.0 g/10 rain to 17.2 g/10 min linearly, meanwhile the impact strength decreased sharply. However, tensile test showed that the yield stress was not affected by the degradation. This indicated that the decreasing in molecular weight led to deceasing of stress at break only. SEM showed that the size of the dispersed rubber phase increased with increasing DCP content, which was also responsible for the decreasing in impact strength.