PLA/PPC/OMMT纳米复合材料的结构与性能研究

采用双螺杆挤出机制备了聚乳酸（PLA）/聚碳酸亚丙酯（PPC）共混物和PLA/PPC/有机改性蒙脱土（OMMT）纳米复合材料，采用偏光显微镜、差示扫描量热仪和力学性能试验机等对共混物和纳米复合材料的相态结构、熔融与结晶行为和力学性能等进行了研究。结果表明，在PPC含量低于30 %时，随着PPC含量的增加，PLA/PPC和PLA/PPC/OMMT体系中PLA的玻璃化转变温度（Tg）均降低，在PPC含量为50 %时出现了明显的相分离；随着PPC含量的增加，PLA/PPC的冲击强度增大；OMMT的含量小于1.5 %时，PLA/PPC/OMMT体系的结晶度、拉伸强度、断裂伸长率和冲击强度均随OMMT含量的增加而增大。

Phase Morphology and Properties of Ternary PLA/PPC/OMMT Nanocomposties

PLA/PPC blends and PLA/PPC/OMMT(organically modified layered silicate) nanocomposites were prepared by melt mixing in a co-rotating twin-screw extruder. Phase morphology, thermal behavior, and mechanical properties of the resultant PLA/PPC blends and PLA/PPC/OMMT nanocomposites were analyzed by polarizing optical microscope, differential scanning calorimetry and universal testing machine equipments, respectively. The results showed that there were two Tg occurred between PLA and PPC, when the loadings of PPC are equal to and more than 30 wt %, which suggests that the compatibility of PLA and PPC becomes worse, and phase separation occurred obviously at the loading of 50 wt % PPC. With the increasing loadings of PPC, the elongation at break of PLA/PPC blends went up. When the mass fractions of OMMT were less than 1.5 wt %,the crystallinity, tensile strength, elongation at break and impact strength of the nanocomposites all increased.