聚乳酸成型加工过程中的熔体粘弹特性和结晶行为调控  

Tailoring the Melt Viscoelasticity and Crystallization Behavior of Poly(lactic acid)during Processing

作　　者：包睿莹[1] 魏馨丰[1] 曹志强 尹海燕[1] 刘正英[1] 杨鸣波[1] 杨伟[1] 

机构地区：[1]四川大学高分子科学与工程学院,高分子材料工程国家重点实验室,成都610065

出　　处：《高分子通报》2017年第10期96-106,共11页Polymer Bulletin

基　　金：国家自然科学基金(21374065,51422305,51503132)

摘　　要：聚乳酸(PLA)是目前合成生物可降解高分子材料中应用量最大的品种,可望逐渐部分取代聚烯烃而更广泛应用于各个领域。但PLA树脂结构决定的松弛特性导致其加工过程特殊的黏弹特性,使其熔体强度低、成型工艺特性不稳定并进而导致产品尺寸和性能不稳定。此外,PLA极低的结晶速率,使其在挤出和注射成型等较高冷却速率的实际加工条件下呈无定型态,进一步影响了其加工和使用性能。这些问题已成为PLA更大规模商品化应用的瓶颈。本文从通过调控PLA熔体加工过程的黏弹特性而提高其可加工性出发,综述近年来本课题组在PLA成型加工过程中熔体粘弹特性和结晶行为(结晶速率和结晶结构)调控方面的研究进展。Poly（lactic acid） （PLA） is one of the most applied synthesized degradable polymer materials and is hopeful to substitute polyolefine to be used in general plastic products. However, due to the particular viscoelastic responses resulting from the relaxation characteristic of PLA resin, the low melt strength of PLA causes the instability during processing, and the instability in size and properties of the products, which limits the development of PLA products. Moreover, PLA is usually amorphous after processing owing to its extremely slow crystallization rate in conventional processing conditions in extrusion and injection molding with high cooling rates. The extremely slow crystallization rate and low crystallinityof PLA result in poor processability and performance, which has become the bottleneck of PLA for large-scale commercial applications. Tailoring crystallization of PLA, including crystallinity and crystalline polymorphism, can achieve high performance of PLA. Based on the enhancement of processability of PLA, this paper gives a review on the controlling of melt viscoelasticity, crystallization rate and stereocomplex crystallization during processing of PLA.

关 键 词：聚乳酸 熔体粘弹特性 结晶速率 立构复合结晶 

分 类 号：O633.14[理学—高分子化学]