拉伸条件下聚乳酸的结晶行为  

Crystallization Behavior of PLA Under Tensile Condition

作　　者：王传琪 何旭[2] Wang Chuanqi;He Xu.(Henan Applied Vocational Technological College, Department of Chemical Engineering,Zhengzhou 450007,Chin;Basic Teaching Department, Chengdu Textile College,Chengdu 611731.Chin)

机构地区：[1]河南应用技术职业学院化工系,河南郑州450007 [2]成都纺织高等专科学校基础教学部,四川成都611731

出　　处：《塑料科技》2018年第7期32-37,共6页Plastics Science and Technology

基　　金：国家自然科学基金青年项目(11304211)

摘　　要：通过红外拉伸技术研究了聚乳酸（PLA）非晶样品的结晶行为。结果发现：样品在接近玻璃化转变温度（Tg）拉伸时加快了分子链运动,其构象不断调整,直接发生了由无序相到有序相的转变;基于热力学和形变对结晶的贡献,在稍高于Tg时,拉伸能促使分子链发生取向,导致分子链间的堆砌越来越紧密,晶体结构不断完善,以至晶体相出现,从而诱导PLA结晶。此外,拉伸过程中所对应的真应变受到温度影响,温度越高,开始结晶时对应的真应变就越小。PLA样品在开始结晶后均出现了明显的应变硬化现象,这说明应变诱导结晶对材料的力学行为也有一定的影响。The cold crystallization behavior of poly（lactic acid）（PLA） amorphous sample was mainly researched by FTIR technology under tensile condition. The results show that the tension can accelerate the chain movement, adjust conformation constantly and then directly happen to the phase transition from disorder to order when approaching Tg. Besides, the tension can promote the chain orientation when slightly above Tg and the molecular interchain packing become closer and closer, the crystal structure is perfected constantly and the crystal phase appears, which cause the crystallization of PLA because of thermodynamics and deformation contribution to crystallization. Moreover, the true strain value corresponding to the tensile process is affected by temperature. With the increase of temperature, the corresponding true strain value becomes smaller. The strain hardening occurred in the PLA samples after the beginning of crystallization, which implies that it has a certain affect on mechanical behavior for materials in the process of strain-induced crystallization.

关 键 词：聚乳酸 拉伸 结构变化 结晶行为 

分 类 号：TQ323.4[化学工程—合成树脂塑料工业]