聚己内酯/聚乳酸共混体系的相形态及其流变行为

Phase morphology and rheological behavior of poly(ε-caprolactone)/polylactide blend

通过熔融共混制备了生物可降解的聚己内酯(PCL)/聚乳酸(PLA)共混体系,采用扫描电镜(SEM)和旋转流变仪分别研究了共混体系不相容的相形态及结构流变学。结果表明,共混体系的相形态强烈依赖于组分比。随PCL组分含量的增加,体系内部球形分散的形态逐渐向纤维状和部分双连续的相形态转变。两相界面的存在增加了体系动态弹性响应,并使体系出现了动态形状松弛。但从共混物模量对频率的依赖性仅能够判断体系是否存在不相容的相界面,相形态的差异则需通过松弛曲线来反映。

Poly （ε-caprolactone）（PCL） /polylactide （PLA） blend was prepared by melt mixing and its morphology and structural rheology were studied by using scanning electron microscope （SEM） and cone- plate rheometer. The results showed that the PCL/PLA blend presented a typical immiscible phase structure, which was dependent on the mass ratio between two components strongly. With increasing PCL component loading level, the morphology of dispersed spherical droplets in the continuous phase changed into fibrous and finally to the co-continuous structure. The presence of the phase interface led to remarkable increase of the dynamic elastic response of the blend, and also to the appearance of dynamic shape relaxation. However, the dependence of modulus on the frequency can only be used to estimate the presence of the immiscible interface, and the detailed differences among those immiscible phase structures should be characterized by relaxation curves.