振动剪切-拉伸场下熔体解缠结对LCB-PP性能的影响  

Impact of Melt Disentanglement on the Properties of LCB-PP under Vibration Shear-Tensile Field

作　　者：孔德超 杜祖臣 李俊杰 张雪颂 高雪芹[1] 傅强[1] KONG Dechao;DU Zuchen;LI Junjie;ZHANG Xuesong;GAO Xueqin;FU Qiang(Sichuan University College of Polymer Science and Engineering,Chengdu 610065,China)

机构地区：[1]四川大学高分子科学与工程学院,四川成都610065

出　　处：《塑料工业》2023年第8期65-72,共8页China Plastics Industry

基　　金：聚合物熔体高效解缠结装置研制及解缠结机理和应用的研究(21627804)。

摘　　要：聚合物的缠结网络是高分子区别与其他小分子化合物的重要特征,分子链间的相互缠结会显著影响聚合物的流变行为、结晶和拉伸性能。本文采用自行设计的振动剪切挤出设备对长支链聚丙烯(LCB-PP)进行处理,实现了熔体解缠结并将低缠结状态有效保留在样品中。研究表明,经振动剪切-拉伸复合应力场处理后LCB-PP的缠结点间平均相对分子质量增加,零切黏度下降比例最高达70%。解缠结后分子链末端松弛时间减小,链运动能力增强使其能更快进行构象调整并规整排列,结晶度和取向度增加。同时生成了的β晶,挤出成型样品的拉伸强度获得提升。The entangled network of polymers was a crucial characteristic that distinguished them from other small molecule compounds.The intermolecular entanglement of polymer chains significantly affected the rheological behavior,crystallization,and tensile properties of polymers.In this study,a self-designed vibrational shear extrusion device was used to process long-chain-branched polypropylene(LCB-PP),achieving the melting entanglement and effectively preserving the low-entanglement state in the pellets.The research indicates that after treatment with a vibrational shear-stretching composite stress field,the average relative molecular weight between entanglement points of LCB-PP increases,and the drop in zero-shear viscosity is as high as 70%.After the disentanglement,the relaxation time of the polymer chain end decreases,and its chain mobility increases,enabling faster conformational adjustment and regular alignment,resulting in an increase in crystallinity and orientation.Moreover,a significant number ofβ-crystals are generated,and the tensile strength of the extruded samples are improved.

关 键 词：解缠结 振动剪切 长支链聚丙烯 黏度 结晶 

分 类 号：TQ325.14[化学工程—合成树脂塑料工业]