“滑轮环”拓扑结构增韧聚乳酸及其形状记忆性能和机理探究

Toughing Polylactide with Topological Slide-ring Structure and Its Shape Memory Effect and Mechanism

通过羟丙基化改性聚轮烷(HPPR)引发L-丙交酯(LLA)开环聚合,将具有机械互锁特性的"滑轮环"拓扑结构引入到聚乳酸体系中,制备了高韧度的"滑轮环"聚乳酸基聚氨酯高分子体系(SR-PLAU),并将其与化学交联的聚乳酸基聚氨酯体系(CC-PLAU),以及聚乳酸/HPPR原位化学共混体系(PLA/HPPR)进行对比研究.结果表明"滑轮环"拓扑结构的引入有效地提高了聚乳酸基材料的拉伸性能,杨氏模量大幅度下降,当"滑轮环"拓扑结构含量为1%(摩尔分数)时,材料的断裂伸长率提高了10倍;"滑轮环"拓扑结构的引入赋予材料优异的形状记忆性能,形状固定率和形状回复率都达到了90%以上.提出了可能的形状记忆机理,并利用材料的应力松弛特性对形状记忆机理进行了分析验证.为材料的增韧改性和新性能研究提供新的理论和思路.

To toughen brittle poly(L-lactic acid),the topological slide-ring architecture was introduced by ring opening polymerization of L-lactic acid initiated by hydroxypropyl modifiedα-CD-based polyrotaxane(HPPR).The thermal properties,mechanical properties,dynamic mechanical properties and shape memory performance of slide-ring polylactic acid based polyurethane(SR-PLAU)and other all samples were investigated.The results show that,the embedding of the slide-ring structure not noly greatly improves the strain at break of polylactic acid,and significantly improves the mechanical properties,but also enables the material good shape memory performance,compared to CC-PLAU and PLA/HPPR.The shape memory mechanism of SR-PLAU was proposed and demonstrated by the stress relaxation characteristics of the materials.