中文摘要：

利用Avrami方程，研究PLA及PLA/PBAT/SiO2复合材料的等温结晶动力学，研究结果表明：PLA及其共混物的Avrami指数n值分别为2.06~2.29和1.91~3.05；样品的结晶常数K(T)、半结晶时间t1/2和结晶速率τ1/2均随结晶温度的升高先增大后减小；在相同的结晶温度条件下，PLA/PBAT/SiO2样品的K(T)和t1/2均高于纯PLA的。采用改进的Avrami方程，分析PLA及PLA/PBAT/SiO2复合材料样品的非等温结晶过程。研究结果表明：PLA及其共混物的Avrami指数n1数值范围为1.31~4.88，表明晶体生长模式均为二维生长和三维生长并存；所有样品的n1均随着升温速率的增大而增大，且n1均小于n2，Zc1和Zc2也随升温速率的增大而增大。基于Mo方程分析结果与基于改进的Avrami方程分析结果一致，进一步证实了纳米SiO2的引入提高了PLA的结晶速率；且PLA/PBAT/SiO2样品的结晶活化能ΔE均大于纯PLA的，说明PBAT及SiO2的引入阻碍了PLA主链的链段向晶体生长表面的迁移过程。

英文摘要：

The isothermal crystallization kinetics of PLA and PLA/PBAT/SiO2composites were investigated byAvrami equation.The results showed that Avrami Indexes(n)of PLA and PLA/PBAT/SiO2composites were2.06~2.29and1.91~3.05respectively.The crystallization constant K(T),semi-crystallization time t1/2and crystallization rateτ1/2were firstly increased and then decreased with the increasing crystallization temperature.The K(T)and t1/2of PLA/PBAT/SiO2composites were higher than those of pure PLA at the same crystallization temperature.Simultaneously,the non-isothermal crystallization kinetics of PLA and PLA/PBAT/SiO2composites were investigated by Avramiequation with Jeziorny improvement,while n1values were ranged from1.31to4.88,indicating the coexistence of twodimensionaland three-dimensional growth in crystal growth pattern.The n1,Zc1and Zc2of all samples were increasedwith increasing heating rate,and n1was less than n2.The result of analysis based on Mo equation was coincident withAvrami equation with Jeziorny improvement,which further indicated that the introduction of nano-SiO2increased thecrystallization rate of PLA.The crystallization activation energyΔE of PLA/PBAT/SiO2composites was greater thanthat of pure PLA,indicating that the introduction of PBAT and nano-SiO2hindered the migration process of the segmentin the main chain of the PLA to the crystal growth on the surface.