聚左旋乳酸/聚消旋乳酸共混物的结晶行为

非晶态聚消旋乳酸(PDLLA)对PLLA的结晶行为有较大的影响。本文利用差示扫描量热仪(DSC)和偏光显微镜(POM)对不同分子量PLLA、PDLLA按不同比例制得的共混物结晶进行了系统研究。结果表明随PDLLA含量的增大PLLA冷结晶温度升高，且越接近熔融温度。PDLLA分子量较小时PLLA球晶特征被明显破坏，PDLLA分子量较大时PLLA更易形保持球晶特征且易形成环带球晶形貌，这与结晶速率与非晶组分的扩散速率匹配程度有关。低分子量的PDLLA使PLLA的最大生长速率对应的温度出现在较低温度。

Crystallization Behavior of PLLA/PDLLA Blends

The existence of amorphous ploy(D,L-Lactic acid) (PDLLA) will influence the crystallization behavior of PLLA. In this work, the Differential Scanning Calorimeter (DSC) and Polarizing Optical Microscope (POM) were used to investigate the crystallization behavior of PLLA/PDLLA blends with different molecular weights and compositions. As a result, the cold-crystallization temperature increases with the increasing of PDLLA content, getting closer to the melting temperature.The adding of PDLLA with smaller molecular weight has greater destruction of the spherulitic morphology, while the spherulites with better regularity and the ring-banded spherulite is more likely to form in the blends with PDLLA having larger molecular weight. It is depending on the degree of the match between the crystallization rate and the diffusion rate of the amorphous component. The maximum growth rate appears at lower temperature for the blend with PDLLA having smaller molecular weight.