温度对二次注射成型聚丙烯连接界面形态与性能的影响

Effect of Temperature on Interfacial Morphology and Properties of Polypropylene During over-Injection Moulding

研究了温度对二次注射成型聚丙烯连接界面形态结构与性能的影响。利用自主设计的注射成型模具制备了不同熔体温度和模具温度的二次注射连接体,利用超薄切片和偏光显微镜研究了不同温度梯度下连接界面不同区域的微观形态差异,通过对外力作用下连接界面破坏机理的讨论,预测了微观结构差异对宏观力学性能的影响,并通过界面剪切力学性能测试加以验证,最终建立了二次注射成型连接界面形态结构与力学性能之间的对应关系。

The effects of melt and mold temperature on interfacial morphology and properties of over-injection molded polypropylene were investigated in this article. The morphology at the interfacial region of over-injection molded specimens at different melt and mold temperature was observed by polarized light microscopy （PLM）. The interface was divided into two regions （S and I）. It is found that trans-crystals grow along the perpendicular direction of the interface at region S. The PLM results show that the region of trans-crystals can be enhanced by increasing melt and mold temperature. The tans-crystals play an important role in improving the interfacial bonding and mechanical properties of over-injection molded polypropylene,which is verified by interfacial shear tensile test.