分子量双峰分布聚乙烯PESP2520的高速流变性能

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吴其晔， 张娜， 慕晶霞， 李鹏

 （青岛科技大学 高分子科学与工程学院，山东 青岛 266042）

 摘要： 采用恒速型毛细管流变仪研究分子量双峰分布聚乙烯PESP2520的高速挤出性能。结果表明：因分子量分布的特殊性，PESP2520的结晶度和熔峰温度均低于对比样品LLDPE7047。高速挤出时PESP2520剪切黏度较高，非牛顿流动性较弱，入口压力降和熔体强度较高。与对比样品比较，PESP2520挤出稳定性好：挤出压力稳定，流动曲线连续，挤出畸变主要为鲨鱼皮畸变。流动稳定性提高的重要原因在于分子量双峰分布使分子链缠结能力下降，熔体/管壁边界应力集中效应弱。

 关键词： 聚乙烯； 分子量分布； 挤出； 流变性

 中图分类号：TQ 325文献标志码： A

 收稿日期： 20140421

基金项目： 国家自然科学基金资助项目（50973050）.

作者简介： 吴其晔(1943—)，男，教授，博士生导师.

 Rheological Properties of PESP2520 with Molecular Weight Distribution of Two Peaks

 WU Qiye, ZHANG Na, MU Jingxia, LI Peng

 (CollegeofPolymerScience and Engineering,QingdaoUniversityof Science and Technology,Qingdao266042,China)

 Abstract: The rheological properties of PESP2520 with molecular weight distribution of two peaks were studied by a capillary rheometer constant speed type. The results indicated that because the specificity of molecular weight distribution, the crystallinity and the melting point of PESP2520 were lower than the contrasting sample LLDPE7047. And the shear viscosity of PESP2520 was higher, the nonNewtonian fluidity weaker, the inlet pressure drop larger and melt strength higher. PESP2520 had better flow stability that was the extrusion pressure was stable, flow curve was continuous, and extrudate surface appeared as lighter sharkskin distortion. The reason of better flow stability depends on the molecular weight distribution of two peaks, it causes a weaker entanglement of molecular chains and a lighter stress concentration at boundary between melt and wall.

Key words: PE; molecular weight distribution; extrusion; rheological property