Flexural, Morphological and Thermal Properties of Poly(Lactic Acid)/ Organo-Montmorillonite Nanocomposites

Abstract

Poly(lactic acid) (PLA)/organo-montmorillonite (OMMT) nanocomposites were prepared by using solution intercalation and melt intercalation methods. For solution intercalation method, toluene was used as solvent. For melt intercalation method, PLA/OMMT composites were prepared by using single-screw extruder. The flexural properties of PLA/OMMT composites have been studied by using three point bending tests. Comparisons between the flexural properties of PLA/OMMT nanocomposites prepared by both methods have been carried out. The microstructures of the PLA/OMMT nanocomposites were assessed by Field Emission Scanning Electron Microscopy (FESEM) and X-ray Diffraction (XRD) analysis. The thermal properties of PLA/OMMT nanocomposites have been characterized by using Differential Scanning Calorimeter (DSC). The flexural modulus of PLA/OMMT nanocomposites prepared by both solution intercalation and melt intercalation methods increased significantly by the addition of OMMT. For both methods, it was found that the optimum flexural properties of the PLA nanocomposites was achieved at 1 wt.% OMMT loading. The dispersion of OMMT in the PLA prepared by solution intercalation is better than that of melt intercalation method. This is attributed to the ease of intercalation of PLA chain into the OMMT layered silicate during the solution intercalation process. XRD results revealed that intercalation of OMMT layered silicate occurred in the PLA matrix.