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文章编号： 1672-6987（2021）04-0054-08； DOI： 10.16351/j.1672-6987.2021.04.008
乔盼， 闫路瑶， 胡海青*， 蔺玉胜， 李媛媛， 赵健
(青岛科技大学 高分子科学与工程学院，山东 青岛 266042)
摘要： 研究了线性分子链结构的无规共聚聚丙烯（PPR）和通过化学接枝改性获得少量长支链结构的高熔体强度聚丙烯（HMSPP）的流动不稳定性以及剪切、拉伸流动性能。结果表明:PPR挤出物出现螺纹状畸变，在高剪切速率下发生熔体破裂与入口区压力不稳定性有关；HMSPP入口压力降在测试范围内没有出现明显的压力波动，挤出物仅表现出螺纹畸变；PPR的剪切黏度随毛细管长径比的增大而增大，毛细管长径比对HMSPP的剪切黏度影响较小；PPR和HMSPP的黏流活化能表现出切应力敏感性；PPR的拉伸黏度表现出拉伸软化行为，HMSPP因其特殊的长支链结构表现出不同程度的拉伸硬化行为。HMSPP的支化结构对拉伸硬化有明显的影响。
关键词： 无规共聚聚丙烯； 高熔体强度聚丙烯； 流动不稳定性； 拉伸硬化
中图分类号： O 063文献标志码： A
引用格式： 乔盼， 闫路瑶， 胡海青， 等. 线性和长支链结构聚丙烯的流动不稳定性［J］. 青岛科技大学学报(自然科学版), 2021, 42(4): 54-61.
QIAO Pan, YAN Luyao, HU Haiqing, et al. Flow instability of linear and long chain branched polypropylene［J］. Journal of Qingdao University of Science and Technology（Natural Science Edition), 2021， 42（4）： 54-61.
Flow Instability of Linear and Long Chain Branched PolypropyleneQIAO Pan, YAN Luyao, HU Haiqing, LIN Yusheng, LI Yuanyuan, ZHAO Jian
（College of Polymer Science and Engineering, Qingdao University of Science and Technology, Qingdao 266042, China）
Abstract: The flow instability, shear and tensile properties of random copolymer polypropylene (PPR) with linear molecular chain structure and HMSPP with high melt strength obtained by chemical graft modification were studied. It was demonstrated that the spiral distortion of PPR extruder and the melt cracking at high shear rate were related to the pressure instability in the entrance zone. The entrance pressure drop of HMSPP did not show obvious pressure fluctuation within the test range, the extrudate only showed screw thread distortion. The shear viscosity of PPR increased with the increase of capillary length-diameter ratio, while the capillary length-diameter ratio had weak effect on the shear viscosity of HMSPP. The activation energies of PPR and HMSPP showed shear stress sensitivity. The elongation viscosity of PPR exhibited elongation softening behavior, well HMSPP exhibited different degrees of elongation hardening behavior due to its special long branched chain structure. The branched structure of HMSPP had obvious effect on elongation hardening.
Key words: random copolymer polypropylene; high melt strength polypropylene; extrusion flow instability; elongation hardening
收稿日期： 2020-07-10
基金项目： 山东省自然科学基金资助项目（ZR2016BM15，ZR201807060363，2017GGX20132）.
作者简介： 乔盼（1994—），男，硕士研究生.*通信联系人.
