Tensile and Morphological Properties of Hybrid Montmorillonite/Microcrystalline Cellulose Filled Polylactic Acid Composites: Effect of Filler Ratio

Abstract

The objective of this study is to investigate the effect of partial replacement of montmorillonite (MMT) with microcrystalline cellulose (MCC) on the tensile and morphology properties of polylactic acid (PLA) composites. PLA composites reinforced with hybrid MMT/MCC were prepared by solution casting. Based on our previous study, tensile strength exhibited that the optimum MMT content in the PLA/MMT is 5 phr. Therefore, partial replacement of MMT with MCC was performed at 5 phr of filler content in order to produce PLA/MMT/MCC hybrid composites. Fourier transform infrared spectroscopy revealed some polar interaction between fillers and PLA matrix. Young’s modulus of the PLA/MMT/MCC hybrid composites increased gradually with increasing MCC filler in the hybrid composites and was higher than PLA/MMT nanocomposites. However, the highest tensile strength of hybrid composites was obtained at 4 phr MMT and 1 phr of MCC filler (~26 MPa), which was lower than optimum formulation of PLA/MMT nanocomposites. Interestingly, the percent elongation at break of the hybrid composites were higher than that of PLA/MMT nanocomposites; increased significantly from ~10 to ~58 %. Field emission scanning electron microscopy indicated the aggregation of MCC and the presence of some cracks in the PLA hybrid composites, resulted in decrease of the tensile strength.