微注射成型HDPE制品的结构和力学性能-《郑州大学学报(工学版)》

文章信息/Info

Title:: The Microstructure and Mechanical Property of Micro-injection Molded HDPE Parts: Effect of Molecular Weight

作者:: 石素宇; 王利娜; 许文仲; 郑国强; 申长雨; 1.河南工程学院材料与化学工程学院,河南郑州,450007;2.郑州大学材料科学与工程学院,河南郑州,450001

Author(s):: Shi Suyu1; Wang Lina1; Xu Wenzhong2; Zheng Guoqiang2; Shen Changyu2; 1. School of Materials and Chemical Engineering, Henan Institute of Engineering, Zhengzhou, Henan, 450007; 2. School of Materials Science and Engineering, Zhengzhou University, Zhengzhou, Henan, 450001

Keywords:: micro-injection molding; HDPE; tensile strength; fracture toughness; molecular weight

摘要:: 采用微注射成型技术制备了两种不同分子量的高密度聚乙烯( HDPE)制品，考察了不同分子量制品的微结构和力学性能.拉伸测试结果表明：与低分子量的HDPE制品相比，高分子量制品的拉伸强度提高了77.5%，同时断裂韧性也增大至低分子量的2倍.综合利用差示扫描量热法(DSC)，广角X射线衍射( WAXD)，小角X射线散射( SAXS)和扫描电子显微镜( SEM)对制品的微结构进行表征，进一步建立了结构-性能的关系，其中拉伸强度较高主要由于制品内分子链和片晶取向程度的增加；此外，制品内shish结构和shish-kebab结构数量的增加也有助于拉伸强度的提高，而制品韧性较高则归因于强的交联网络的形成.

Abstract:: The high density polyethylene ( HDPE ) parts with two different molecular weights were prepared with micro-injection molding. The dependence of microstructure and mechanical properties of samples with dif-ferent molecular weight were examined. Tensile test indicated that the increase to 77. 5% in tensile strength was achieved for HDPE parts with higher molecular weight. At the same time, the toughness of HDPE parts were enhanced about twice as compared with that of lower molecular weight. In this study, microstructure characterizations, including differential scanning calorimetry ( DSC) , wide-angle X-ray diffraction ( WAXD) , small-angle X-ray scattering ( SAXS) and scanning electronic microscope ( SEM) were emplayed/conducted to investigate the variations of microstructure and further established the relationship between microstructure and mechanical properties. It suggested that the increased molecular and crystalline orientation led to the reinforce-ment. Formation of more shish and shish-kebab structure was in favor of the enhanced strength as well. The notable improvement of toughness in the higher molecular weight parts should be ascribed to formate a strong physical crosslinking network.