摘要
增韧改性聚乳酸(PLA)的结晶行为对材料耐热性、降解和力学性质影响较大。主要研究了含有不同手性聚乳酸的聚氨酯弹性体(D-PU和L-PU)增韧左旋聚乳酸(PLLA)的结晶形态学与动力学。弹性体链上相同手性聚乳酸链段对共混物的结晶成核影响较小,但在相反手性共混物中,由于界面构筑立构复合作用(sc-PLA),D-PU在PLLA基体中的散程度得到显著提高,促进基体形成大量细小球晶,与纯PLLA相比,成核密度提高了4~5个数量级,但生长速率降低。等温结晶动力学分析表明,PLLA/D-PU共混材料的半结晶时间缩小一半以上,这表明,D-PU促进了PLA的总结晶速率的提升。研究表明,界面sc-PLA在增韧聚乳酸体系结晶形态和动力学方面具有重要的影响,是调控聚乳酸基材料结构与性能的有效方法。
The crystallization behavior of toughened polylactide(PLA)possessed a close relation with the heat resistance,degradation and mechanical properties of the material.The crystal morphology and crystallization kinetics of poly-L-lactide(PLLA)toughened by polyurethane elastomers containing different chiral polylactide(D-PU and L-PU)were investigated.The polylactide segments with the same chirality on elastomer backbone had little effect on the crystallization behavior of the blend,but the dispersion of D-PU in the PLLA matrix was significantly improved by the formation of the interfacial stereocomplex(sc-PLA),and the nucleation density increased by 4~5 orders of magnitude compared with pure PLLA,which also promoted the formation of a large number of fine spherulites and reduced the growth rate.Isothermal crystallization kinetic analysis showed that the half crystallization time of the PLLA/D-PU was reduced by more than 2 times,conforming that the addition of D-PU promoted the increase of the total crystallization rate of PLA.This study showed that interfacial sc-PLA had an important influence on the crystalline morphology and kinetics of the toughened polylactide system,and was a powerful means to control the structure and properties of polylactide-based materials.
作者
杨康杰
周文娟
方华高
YANG Kangjie;ZHOU Wenjuan;FANG Huagao(Hefei University of Technology,Hefei,Anhui 230009,China)
出处
《塑料》
CAS
CSCD
北大核心
2022年第3期7-12,共6页
Plastics
关键词
聚乳酸
聚氨酯弹性体
立构复合结晶
结晶形态
结晶动力学
polylactide
polyurethane elastomer
stereocomplex
crystal morphology
crystallization kinetics
