高熔体强度聚丙烯的结构与性能  

Structure and Properties of High Melt Strength Polypropylene

作　　者：魏红悦 史为轩 赵世成[1] Wei Hongyue;Shi Weixuan;Zhao Shicheng(School of Chemical Engineering,East China University of Science and Technology,Shanghai 200237,China)

机构地区：[1]华东理工大学化工学院,上海200237

出　　处：《工程塑料应用》2023年第5期104-109,共6页Engineering Plastics Application

基　　金：国家自然科学基金项目(21878089)。

摘　　要：为了揭示高熔体强度聚丙烯(HMSPP)的结构特征及其对性能的影响,研究了两种商业级长支链型高熔体强度聚丙烯(LCB-HMSPP)和一种线性聚丙烯(PP)的流变学行为、熔体强度、力学性能,并结合高温凝胶渗透色谱(GPC)与三检测器联用技术探究了HMSPP的基本结构,在此基础上分析了表征PP长链支化结构的方法。结果表明,LCB-HMSPP中存在支化结构,和线性PP相比,LCB-HMSPP有较高的分子量和较宽的分子量分布。LCB-HMSPP具有明显不同于线性PP的流变学特征,与线性PP相比,LCB-HMSPP出现剪切变稀现象,零剪切黏度变大,松弛时间变长,表现出明显的拉伸应变硬化行为,且应变硬化程度与GPC测得的支化程度及熔体强度结果相对应,即应变硬化程度与熔体强度呈正相关。另外,长支链结构对于改善PP的力学性能有积极作用,尤其能够显著提高PP的韧性。In order to reveal the structural characteristics of high melt strength polypropylene(HMSPP)and its influence on the properties,the rheological behavior,melt strength,and mechanical properties of two commercial grade long branched high melt strength polypropylene(LCB-HMSPP)and one linear polypropylene(PP)were investigated,and the basic structure of HMSPP was investigated by combining high temperature gel permeation chromatography(GPC)with triple detector coupling technique.On this basis,a method to characterize the long-chain branched structure of PP was analyzed.The results show that there is a branched structure in LCB-HMSPP,which has a higher molecular weight and a wider molecular weight distribution compared to linear PP.Compared with linear PP,LCB-HMSPP shows shear thinning,larger zero-shear viscosity,longer relaxation time,and obvious tensile strain hardening behavior,and the degree of strain hardening corresponded to the branching measured by GPC and melt strength results,which means that the degree of strain hardening is positively correlated with the melt strength.In addition,the long branched structure has a positive effect on improving the mechanical properties of PP,especially it can significantly improve the toughness of PP.

关 键 词：聚丙烯 长支链 流变行为 熔体强度 应变硬化 

分 类 号：TQ325.14[化学工程—合成树脂塑料工业]