PREPARATION AND CHARACTERIZATION OF POLY LACTIC ACID/ZINC OXIDE PILLARED SAPONITE NANOCOMPOSITES

Poly lactic acid(PLA)/zinc oxide(ZnO) pillared saponite nanocomposites were prepared with ZnO pillared saponite synthesized via microwave hydrolysis method. The structure of ZnO pillared saponite and PLA/ZnO pillared saponite nanocomposites were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM). Moreover, the mechanical properties and thermostability of PLA/ZnO pillared saponite nanocomposites were studied. The microstructure showed that the ZnO pillared saponite appeared as exfoliated or partially intercalated nanometer layers, and the TEM showed that the ZnO pillared saponites were evenly dispersed in the PLA matrix in the form of exfoliated layers. The mechanical properties showed that the elongation at break of PLA nanoncomposites was improved when the loading content of ZnO pillared saponite was 0.3 wt%. SEM analysis demonstrated that a visible transformation took place in the section morphology which manifested the toughness of PLA nanocomposites; DSC results displayed that the ZnO pillared saponite decreased the glass transition temperature and cold crystallization temperature, and obviously promoted the crystallinity, which was in accordance with XRD analysis. TG-DTA analysis showed that the thermostability of PLA/ZnO pillared saponite nanocomposites was improved. In a word, a hererogeneous nucleation effect of ZnO pillared saponite on the PLA matrix was testified and all the results showed that the ZnO pillared saponite played an active role in accelerating the crystallization process of PLA matrix.