聚乳酸/纳米SiO_2复合材料的熔融和冷结晶行为

采用熔融共混法制备了聚乳酸(PLLA)/纳米SiO2复合材料;利用透射电镜观察了复合材料的微观形貌;利用差示扫描量热仪测定了该复合材料的熔融行为和非等温冷结晶行为;利用Jeziorny法和Mo法研究了PLLA及其复合材料的非等温冷结晶动力学.结果表明,纳米SiO2在PLLA基体中具有良好的分散性和异相成核作用,使得PLLA基体的结晶峰向低温方向移动;复合体系的熔融温度和熔融焓的变化与SiO2的加入量密切相关.采用Jeziorny法和Mo法均可以很好地处理复合材料的非等温冷结晶过程.

Melting behavior and cold crystallization of poly(L-lactic acid)/nano-silica composite

Poly（L-lacticacid）/nano-silica（denoted as PLLA/nano-SiO2） composites were prepared by melting blending.The micro-morphology of as-prepared PLLA/nano-SiO2 composites was observed with a transmission electron microscope.The melting behavior and non-isothermal cold crystallization behavior of pure PLLA and PLLA/nano-SiO2 composites were analyzed by differential scanning calorimetry.Moreover,the non-isothermal cold crystallization kinetics of PLLA and PLLA/nano-SiO2 composites was analyzed by Jeziorny model and Mo model.Results indicate that SiO2 nanoparticles are homogeneously dispersed in PLLA matrix to promote the cold crystallization of the matrix via heterogeneous nucleation.Moreover,both Jeziorny model and Mo model can be well adopted to describe the non-isothermal cold crystallization processes of as-prepared PLLA/nano-SiO2 composites.