Abstract
The objective of this study is to investigate the effects of partial replacement of montmorillonite (MMT) with microcrystalline cellulose (MCC) on the biodegradability and thermal properties of hybrid MMT/MCC filled polylactic acid (PLA) composites prepared using solution casting technique. Based on our previous study, the optimum MMT content based on having the highest tensile strength in PLA/MMT nanocomposites is 5 phr (parts per hundred parts of polymer). Therefore, the PLA/MMT/MCC hybrid composites were prepared at a total filler content of 5 phr. The biodegradability and thermal properties of PLA hybrid composites were investigated using soil burial test and thermogravimetric analysis, respectively. The biodegradability of PLA/MMT/MCC hybrid composites (1 phr MMT and 4 phr MCC) at 8th week significantly increased by approximately 228% and 367% compared to the optimum formulation of PLA/MMT nanocomposite and neat PLA, respectively. In addition, Fourier transform infrared spectroscopy (FTIR) revealed the formation of hydrogen bonding between the fillers and PLA matrix. The thermal stability of hybrid composites improved from 358.3 to 362.2 °C by incorporation of hybrid MMT/MCC (1 phr MMT and 4 phr MCC) into PLA matrix, as demonstrated by maximum decomposition temperature.