动态保压成型下中等分子量聚乙烯串晶形成的影响

The effect of the shish-kebab structure formation of middling-PE molded by dynamic packing injection

采用自制的动态保压注射成型(DPIM)装置,向中等分子量的HDPE中添加高、低分子量聚乙烯(HMWPE、LMWPE)双重诱导成型自增强串晶的组织与性能影响进行研究。实验表明,在双重诱导和采用DPIM装置下,试样产生了大量的串晶结构,在160℃动态保压注射试样的拉伸强度为111.6 MPa,是其HDPE纯料静态试样拉伸强度24.5 MPa的4.56倍,提高了355.5%;通过WAXD、DSC和SEM测试可知,在DPIM下,试样产生互锁紧密的串晶结构;高分子量聚乙烯的加入有利于串晶脊纤维晶体的生成,低分子量聚乙烯的加入有利于片晶生长增厚,从而使得串晶结构更完善。

The influence of self-enhancement and shish-kebab of the middling-HDPE added high molecular weight PE and low molecular weight PE was studied by using the self-designed and self-made dynamic packing injection molding( DPIM) equipment. Testing results show that tensile strength of dynamic sample was 111. 6 MPa at 160 ℃,which was4. 56 times as high as the static one( 24. 2 MPa) and approximately increased by 355. 5%; it was known that,from the test results of differential scanning calorimetry( DSC),scanning electron microscopy( SEM) and wide-angle X-ray diffraction( WAXD),the interlocking structure of shish-kebab was generated under the acts of DPIM. Adding high molecular weight PE can be beneficial to the formation of shish-kebab spine fiber crystal and the thickness of lamellar crystal was benefit from adding low molecular,so as to improve the property of shish-kebab.