微型注塑对聚乳酸/聚丁二酸丁二醇酯共混物的形貌结晶和力学性能的影响  

Effect of Microinjection Molding Conditions on Morphology,Crystallization and Mechanical Properties of Poly(lactic acid)/Poly(butylene succinate)Blends

作　　者：姜向升 陈英红[1] 王萌[1] 谢页平 Xiangsheng Jiang;Yinghong Chen;Meng Wang;Yeping Xie(State Key Laboratory of Polymer Materials Engineering,Polymer Research Institute of Sichuan University,Chengdu 610065,China)

机构地区：[1]高分子材料工程国家重点实验室四川大学高分子研究所,四川成都610065

出　　处：《高分子材料科学与工程》2020年第6期70-78,共9页Polymer Materials Science & Engineering

基　　金：国家自然科学基金资助项目(51773121,51721091);四川省青年科技创新研究团队专项计划(2016TD0010)。

摘　　要：以聚丁二酸丁二醇酯(PBS)为分散相,聚乳酸(PLA)为基体树脂制备了PLA/PBS共混物,实现其微型注塑。结合流变行为和ANSYS Polyflow计算机模拟研究了微型注塑条件(包括熔体温度和注射速率)对PLA/PBS共混物结构和性能的影响。结果表明,微型注塑过程中强的剪切和拉伸应力场实现了PBS在PLA基体中的原位成纤,微型注塑条件对PBS分散相纤维形貌、基体树脂PLA结晶行为以及共混物力学性能有重要影响。发现提高熔体温度有利于增强壁面滑移效应,降低浇口区域的负拉伸作用,改善熔体流场的稳定性,从而有利于分散相PBS的原位成纤,然而过高的注射速率会因强负拉伸作用而破坏纤维结构,不利于PBS的原位成纤和共混物力学性能的改善。PBS原位成纤及其诱导PLA形成的取向结晶结构有利于共混物力学性能的改善。PLA/PBS blends were prepared by using poly(butylene succinate)(PBS)and poly(lactic acid)(PLA)as dispersed phase and matrix,respectively.Then,the microinjection molding of prepared PLA/PBS blend was conducted.Combined with the rheological measurement and ANSYS Polyflow computer simulation,the effects of microinjection molding conditions,including injection speed and melt temperature,on the structure and properties of PLA/PBS blends were studied.The results show that the strong shear and stretch fields generated during microinjection molding process could realize the in-situ fibrillation of PBS in the PLA matrix,and the microinjection molding conditions have important influences on the morphology of the dispersed PBS fiber,the crystallization behavior of the PLA matrix and the mechanical properties of the blends.It is found that the increase of melt temperature is beneficial to wall slip effect,reduction in negative tensile effect in gate area and enhancement in melt flow stability,thus facilitating the in-situ fibrillation of PBS.However,the excessively high injection speed would destroy the fiber structure due to negative tension effect,which is not conducive to the in-situ fibrillation of PBS and hence the property improvement of blends.The in-situ formed PBS fiber structures and their induced-formation of PLA oriented crystal structures are beneficial to the improvement in the mechanical properties of the blends.

关 键 词：聚乳酸 共混物 微型注塑 原位成纤 壁面滑移 断裂伸长率 

分 类 号：TQ320.66[化学工程—合成树脂塑料工业]