动态保压注塑成型中少量HMWPE的诱导对HDPE结晶的影响

Effect of a little HMWPE on Crystallization of HDPE in Dynamic Packing Injection Molding

探讨了在动态保压注射成型中少量高摩尔质量聚乙烯(HMWPE)的诱导作用对高密度聚乙烯(HDPE)结晶行为的影响。通过扫描电子显微镜(SEM)可观测到HDPE在HMWPE诱导下生成了一种类似网状的串晶结构。该结构沿流动方向高度取向,垂直流动方向的片晶相互连接。实验结果证明,该结构可以同时大幅度提高试样的强度和韧性,其结构大大优于一般的串晶结构。差示扫描量热法(DSC)测试结果表明,少量HMWPE诱导的HDPE动态成型试样(B4)结晶度明显高于普通成型试样(S0)和未加高分子诱导的动态成型试样(B0)。广角X射线衍射(WAXD)结果显示B4内部晶体沿着流动方向的取向度也明显高于S0和B0。本研究可得到如下结论:少量HMWPE确实能有效诱导HDPE的结晶和取向,使HDPE的结晶行为得到明显改善。

The effect of a little amount of HMWPE on the crystallization of HDPE in dynamic packing injection molding （DPIM） was studied. The SEM results showed the much better web-like shish-kebab structure, in which most of the lamellae connect different columns, compared with conventional shish-kebab, was formed in HDPE blends induced by HMWPE in DPIM. With the aid of DSC and WAXD measurements, the crystallinity and orientation degrees of the induced samples were much higher than those of samples molded by static packing injection molding and no induced samples molded by DPIM. All the results showed that HMWPE would increase the crystallinity and orientation degrees of HDPE, and its crstallization could be improved apparently.