UHMWPE/HDPE/纳米SiO2共混体系的毛细管挤出流变行为  

Rheological Behavior in Capillary Extrusion of UHMWPE/HDPE/Nano-SiO2 Blends

作　　者：刘丽超[1] 王非 付丽 薛平[1] 田静 LIU Lichao;WANG Fei;FU Li;XUE Ping;TIAN Jing(Institute of Plastic Machinery and Engineering,Beijing University of Chemical Technology,Beijing 100029,China;School of Material and Mechanical Engineering,Beijing Technology and Business University,Beijing 100048,China)

机构地区：[1]北京化工大学,塑料机械及塑料工程研究所,北京100029 [2]北京工商大学材料与机械工程学院,北京100048

出　　处：《塑料》2020年第2期36-39,共4页Plastics

基　　金：国家自然科学基金(51673021)。

摘　　要：采用毛细管流变仪,研究了超高分子量聚乙烯(UHMWPE)/高密度聚乙烯(HDPE)/纳米二氧化硅(SiO2)共混体系,及其对照组的流变行为和挤出过程中的不稳定流动现象,分析了共混物发生鲨鱼皮畸变和整体破裂的临界剪切应力和临界剪切速率的变化情况。结果表明,经过偶联剂改性的纳米SiO2粒子,在PE基质的共混体系中存在一定的界面黏附作用,降低了纳米共混体系的挤出胀大比,弹性特征减轻。这种界面相互作用限制了纳米共混材料在口模区域的黏性流动以及分子链离开口模后的构象恢复,降低了发生流动不稳定现象的临界剪切速率,发生鲨鱼皮畸变的临界剪切应力增大,整体破裂后,形成交替出现"鲨鱼皮-破裂"的振荡性变化外观。Rheological behaviors and the flow instabilities in the extrusion process of ultra-high molecular weight polyethylene(UHMWPE)/high-density polyethylene(HDPE)/nano-SiO2 blends and their control groups were investigated using capillary rheometer.The changes of critical shear stress and critical shear rate for sharkskin distortion and global fracture of blends were analyzed.The results showed that modified nano-SiO2 particles by the coupling agent were detected a certain interfacial adhesion in PE matrix,which reduced the extrudate swell and the elastic properties of the nanocomposite.The interfacial interaction limited viscous flow of nanocomposite inside the die and conformational recovery of molecular chains after leaving the die,thus reducing the critical shear rate of flow instabilities and increasing the critical shear stress of sharkskin distortion,and causing an oscillating appearance change of alternate"sharkskin-melt fracture"after the global extrusion fracture.

关 键 词：超高分子量聚乙烯 纳米二氧化硅 毛细管挤出 流变 熔体破裂 

分 类 号：TQ325.12[化学工程—合成树脂塑料工业]