文献类型：期刊文献

中文题名：基于毛细管挤出的PE?UHMW/PE?HD共混物不稳定流动行为分析

英文题名：Analysis of unstable flow behavior in PE?UHMW/PE?HD blends during capillary extrusion

作者：徐成龙[1];王玉[1];李果[1];谢林生[1];马玉录[1]

机构：[1]华东理工大学机械与动力工程学院,上海200237

年份：2025

卷号：39

期号：11

起止页码：13

中文期刊名：中国塑料

外文期刊名：China Plastics

收录：;北大核心:【北大核心2023】；

语种：中文

中文关键词：超高分子量聚乙烯;毛细管挤出;流变特性;不稳定流动;熔体破裂

外文关键词：ultra-high molecular weight polyethylene;capillary extrusion;rheological property;unstable flow

摘要：针对超高分子量聚乙烯在熔融挤出过程中容易产生挤出缺陷的问题,借助毛细管流变仪挤出超高分子量聚乙烯(PE-UHMW)/高密度聚乙烯(PE-HD)共混物,通过观察纯PE-UHMW、纯PE-HD及共混挤出物的表面形貌,分析了不同挤出温度下共混物的不稳定流动行为,包括挤出过程中发生振荡畸变和熔体破裂现象的临界剪切速率,以及超过临界剪切速率后挤出物的压力振荡行为和壁面滑移现象。结果表明,共混物的挤出形貌经过了鲨鱼皮-振荡畸变-整体熔体破裂的演变过程。毛细管挤出温度为260℃时,当剪切速率达到116 s^(-1)后,挤出压力产生剧烈振荡,熔体与管壁界面存在动态黏-滑转变特征,引起挤出物的振荡畸变和壁面滑移现象。同时,挤出温度的升高可以延缓挤出物不稳定流动的发生,引发振荡畸变形貌发生的剪切速率区间从116~522 s^(-1)增加至152~686 s^(-1)。
This study investigated the unstable flow behavior of ultra-high molecular weight polyethylene(PE-UHMW)/high-density polyethylene(PE-HD)blends during capillary extrusion.The surface morphology of extrudates,including pure PE-UHMW,pure PE-HD,and their blends,was analyzed to characterize flow instabilities at various extrusion tem-peratures.Key phenomena examined include the critical shear rate for the onset of oscillatory distortion and melt frac-ture,as well as pressure oscillations and wall slip beyond this critical rate.The results indicated that the extrusion mor-phology evolved through a sequence of shark skin,oscillatory distortion,and global melt fracture.At an extrusion tem-perature of 260℃,severe pressure oscillations occurred at a shear rate of 116 s^(-1),accompanied by a dynamic stick–slip transition at the melt–wall interface that induces oscillatory distortion and wall slip.Furthermore,increasing the extru-sion temperature delayed the onset of unstable flow,expanding the shear rate range for oscillatory distortion from 116~522 s^(-1) to 152~686 s^(-1).