不同初始条件下聚乳酸的等温结晶动力学  

Isothermal Crystallization Kinetics of Polylactic Acid from Different Initial States

作　　者：冯立栋[1,2] 高战团[1,2] 边新超[1,2] 陈志明 陈学思[1,2] 陈文启[1,2] 

机构地区：[1]中国科学院长春应用化学研究所,高分子物理与化学国家重点实验室,长春130022 [2]浙江海正生物材料股份有限公司,浙江台州318000

出　　处：《功能高分子学报》2009年第2期142-147,共6页Journal of Functional Polymers

基　　金：浙江省科技计划项目(2004C13020);国家科技部攻关计划项目(2005BA314C);国家发展改革委员会高新技术产业化项目(20062352)

摘　　要：用差示扫描量热法（DSC）研究聚乳酸（PLA）从熔体及玻璃态两种初始状态下的等温结晶行为，考查结晶动力学参数与结晶温度（t）及初始状态的关系。实验结果表明：从玻璃态结晶活化能（359kJ／mol）较从熔体结晶活化能（103kJ／mol）高；相应的Avrami指数n（2．3～2．7）小于从熔体的（2．5～3．1）；所测得的平衡熔点是一致的，分别为155．7℃（玻璃态）、156．4℃（熔体）；从玻璃态结晶诱导时间（￡i）随着Tc升高而逐渐减小，从熔体结晶丁。-95℃时，出现最小ti为9．47min；在整个T。区间，从玻璃态结晶速率（G）都受生长控制，从熔体低温时G受生长过程控制，高温时受成核过程控制。The isothermal crystallization kinetics of polylactic acid （PLA） was investigated by differential scanning calorimeter （DSC）, and two initial states, polymer melt and glass state, were concerned particularly. The influences of initial states of PLA and various temperatures on the crystallization behavior were discussed. When PLA is isothermally crystallized from glass state, activation energy （359 kJ/mol） is higher than that from polymer melt （103 kJ/mol）. Exponent of Avrami, n, is just reverse; the former is 2.3--2.7 and the latter is 2.5--3.1. There is no appreciable distinction between the equilibrium melting points, respectively 156.4 ℃ from polymer melt and 155.7℃ from another. From glass state, induced time decreases gradually with the increasing of crystallization temperature. When crystallized from polymer melt, the shortest induced time （9.47 min） is observed at 95℃. Furthermore, the control steps of PLA crystallization rate, in the whole temperature range, are different owing to their initial states. Initiated from the glass state, the rate depends strongly on crystal growth process. While initiated from the melting state, the rate is controlled by the foregoing rule at low temperature, and by nucleation process at high temperature.

关 键 词：聚乳酸 等温结晶动力学 熔体 玻璃态 

分 类 号：O631[理学—高分子化学]