流动诱导大量聚乳酸shish-kebab结构生成及其在注塑成型中实现

项目名称： 流动诱导大量聚乳酸shish-kebab结构生成及其在注塑成型中实现

项目编号： No.51203104

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 有机高分子材料学科

项目作者： 钟淦基

作者单位： 四川大学

项目金额： 25万元

中文摘要： 流动诱导生成的串晶（shish-kebab）结构可显著提高半结晶聚合物制品性能，但由于聚乳酸的分子链呈半刚性且分子量较低， shish-kebab 结构形成所需的流动场条件苛刻，因此，迄今为止，尚未在注塑制品中生成大量shish-kebab 结构的报道。本课题拟在注塑保压阶段，模具型腔中施加强的振动流动场，促进聚乳酸分子链取向，发生流动诱导结晶，并添加少量与之相溶的聚乙二醇增加分子链活动能力，提高结晶速率，抑制shish 的松弛，制备含大量shish-kebab 结构的聚乳酸注塑制品，提高聚乳酸制品的力学性能。本课题拟系统研究流动场诱导PLLA 结晶规律和形成shish-kebab 结构的临界条件、实际加工流动场下PLLA shish-kebab 结构形成规律，以及结构与性能的关系，为聚乳酸加工中的形态调控及其高性能化提供理论指导。

中文关键词： 聚乳酸；流动场；串晶；注塑；性能

英文摘要： The properties of semicrystalline polymers can be improved significantly by introduction of flow-induced shish-kebab structure, however, for the biodegradable polymer of poly(L-lactide) (PLLA), it is hard to fullfill the critical conditons for formation of the shish-kebab structure of PLLA due to it's low molecular weight and the nature of semi-rigid chain, thereby the PLLA product with plenty of shish-kebab structure of PLA has not been reported yet. In this project, we plan to promote the formation of shish-kebab structure by introducing a high flow field into the cavity of injection mold, in addtion, small amount of compatible polyethylene glycol is added to increase the mobility of polylactide chains, aiming to improve crystallization rate and suppress the relaxation of shish. Thus, the injection molded PLA products containing plenty of shish-kebab structure are expect to be fabricated. By investigation of flow-induced crystallization of PLA and the critical condition of the shish-kebab formation, and exploring the rule of shish-kebab formation in PLA under injection molding as well as the structre-property relationship, it is promising to give some valuable theory guideline and technical support for manipulating the structure of PLA and achievement of the high performance parts.

英文关键词： polylactide；flow field；shish-kebabs；injection molding；properties