滑石粉对PLA/PBAT共混物非等温结晶行为的影响

Influence of Talc on Nonisothermal Crystallization Behaviors of PLA/PBAT Blends

采用差示扫描量热法研究了滑石粉（Talc）对聚乳酸/聚己二酸-对苯二甲酸丁二醇酯（PLA/PBAT）共混物非等温结晶行为的影响。结果表明,随着Talc用量的增加,结晶完成时间缩短,结晶温度向高温移动,且结晶度增大,这说明Talc可以起到异相成核剂的作用,显著提高共混物的结晶能力。此外,降温速率对共混物的非等温结晶行为也有显著影响。较低的降温速率有利于得到结晶度更高的PLA/PBAT共混材料。利用Jeziorny法对共混物的非等温结晶动力学进行研究。结果发现,在相同降温速率下,随着Talc含量的增加,结晶速率常数显著增大,而半结晶时间随之减小。在不同降温速率下得到的含Talc共混物的Avrami指数（n）接近3,故其成核机理是以异相成核为主,球晶生长方式为三维生长。

Nonisothermal crystallization behaviors of PLA/PBAT were studied by differential scanning calorimetry（DSC）. The results show that, with the increasing Talc content of PLA/PBAT blends, the crystallization time reduces, and the crystallization temperature shifts to higher temperature range. Meanwhile, the crystallinity of the blends also shows an obvious increase. It is confi rmed that Talc makes a strong heterogeneous nucleating effect to enhance the crystallization ability of the PLA/PBAT blends. In addition, cooling rate also has a signifi cant impact on the nonisothermal crystallization behaviors. It is favorable to obtain the PLA/PBAT blend with higher crystallinity under a lower cooling rate. The nonisothermal crystallization kinetics was studied by using Jeziorny method. The results indicate that, at the same cooling rate, crystallization rate constant increases largely, and crystallization half-time decreases with increasing Talc content. Each calculated Avrami index（n） of the blends at diff erent cooling rates is close to 3. It is revealed that the heterogeneous nucleation and 3 D growth are more likely to occur at the presence of Talc.