摘要:以滑石粉(Talc)作为成核剂,采用密炼机熔融混炼制备了聚乳酸(PLA)基生物降解材料,研究了增塑剂与成核剂对PLA结晶能力的影响。采用DSC研究了PLA/Talc共聚体系的等温结晶动力学和非等温结晶动力学,在降温速率分别为1、2.5、5和10℃/min的条件下,研究了PLA/Talc共聚体系的非等温结晶动力学;同时对PLA/Talc共聚体系进行了等温结晶动力学的研究,在一定温度范围下,等温结晶后的各试样在熔融时,会出现两个熔融峰。对所得数据用Avrami方程进行了处理,并计算了其活化能,结果表明:随着成核剂滑石粉的加入,加快了成核速率和球晶生长速率,缩短了半结晶时间并降低了活化能,表明滑石粉是有效的成核剂。
关键词:聚乳酸;增塑剂;成核剂;非等温结晶动力学;等温结晶动力学
Abstract:The polylactic acid (PLA) based biodegradable materials were prepared by using internal mixer,which took the method of melt-mixing,talcum powder (talc) as nucleating agent. We have studied the influence of plasticizer and nucleating agent to the crystallization of PLA. The nonisothermal crystallization kinetics and isothermal crystallization kinetics of PLA and its composites with talc was analyzed by DSC ,at different cooling rates of 1,2.5,5 and 10℃/min, The nonisothermal crystallization kinetics of PLA and its composites with talc was analyzed by DSC; and The isothermal crystallization kinetics of PLA and its composites with talc was analyzed by DSC, In a certain temperature range, the samples after isothermal crytallization in the melt, there will be two melting peaks. Processing of the data obtained using the Avrami equation and calculate its activation energy,The results showed that: With the addition of nucleating agent talc, accelerated the nucleation rate and spherulite growth rate, shorten the half crystallization time and reduces the activation energy,That talc is an effective nucleating agent.
Key words: polylactic acid;plasticizer;nucleation agent;the nonisothermal crystallization kinetics; the isothermal crystallization kinetics.