分子量分布对HDPE微孔膜结构与性能的影响  

Effect of Molecular Weight Distribution on Structure and Properties of HDPE Microporous Membrane

作　　者：黄恒辉 田子钦 苏植祥 谢嘉宜 徐睿杰[1] 雷彩红[1] HUANG Henghui;TIAN Ziqin;SU Zhixiang;XIE Jiayi;XU Ruijie;LEI Caihong(School of Materials and Energy,Guangdong University of Technology,Guangzhou,Guangdong 510006,China)

机构地区：[1]广东工业大学材料与能源学院,广东广州510006

出　　处：《塑料》2020年第6期98-102,共5页Plastics

基　　金：国家自然科学基金(51773044,51603047)。

摘　　要：采用2种重均分子量相似、分子量分布不同的高密度聚乙烯作为原料,通过熔体拉伸法制备了高密度聚乙烯微孔薄膜,研究了不同分子量分布对高密度聚乙烯微孔膜结晶结构及其成孔性能的影响。实验结果表明,与分子量分布较窄的HDPE2相比,分子量分布较宽的HDPE1中,低分子量部分具有增塑作用,然而高分子量部分缠结程度较高,松弛时间较长,导致临界缠结分子量小,非晶区缠结密度和tie链体积分数较大,因此,由其制备的微孔薄膜片晶侧向尺寸比HDPE2短38.2 nm,使其在后拉伸过程中,表现出更大的屈服应力和拉伸硬化模量。并且,在相同的工艺条件下,由HDPE1制备的微孔膜片晶分离程度更大,平均孔径比HDPE2大8.5 nm,能够表现出更好的成孔性。Two types of HDPE resins with similar weight-average molecular weight and different molecular weight distribution were selected to prepare HDPE microporous membrane by melt-stretching.The effect of molecular weight distribution on the crystalline structure and the stretched porosity in the HDPE microporous membrane was investigated.The results demonstrated that,compared with HDPE2 with narrow molecular weight distribution,the low molecular weight part of HDPE1 with broad molecular weight distribution had a plasticizing effect.The high molecular weight part of HDPE1 had a greater degree of entanglement and longer relaxation time,which resulted in a smaller critical entangled molecular weight,larger entangled density in the amorphous region and the larger tie chain volume fraction.Lateral crystal size of HDPE1’s microporous membrane was 38.2 nm shorter than that of HDPE2,which resulted in larger yield stress and hardening modulus during the post stretching process.And under the same processing conditions,the micro-porous membrane prepared by HDPE1 had a greater degree of lamellae separation and a larger average pore size than HDPE2 by 8.5 nm,which had better porosity.

关 键 词：高密度聚乙烯树脂 分子量分布 片晶结构 缠结分子量 力学性能 

分 类 号：TQ325.12[化学工程—合成树脂塑料工业]