摘要
非晶态聚消旋乳酸(PDLLA)对聚左旋乳酸(PLLA)的结晶行为有较大的影响。本文利用差示扫描量热仪和偏光显微镜对不同分子量PLLA、PDLLA按不同比例制得的共混物结晶进行了研究。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。
The existence of amorphous ploy(D,L-Lactic acid)(PDLLA) will influence the crystallization behavior of Ploy(L-Lactic acid)(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.When the molecular weight of PDLLA is small,the spherulite characteristics of PLLA are obviously destroyed.When the molecular weight of blending PDLLA is large,PLLA is more likely to maintain the spherulitic characteristics,and it is easy to form a ring-shaped spherulitic morphology.It is depending on the degree of matching between the crystallization rate and the diffusion rate of the amorphous component.The maximum growth rate appears at lower temperature while blending with PDLLA that have smaller molecular weight.
引文
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