Effect of Acetylation and MAPE on the Properties of Steam-Exploded Acacia mangium Fiber—HDPE Composites

Abstract

Composites of high-density polyethylene (HDPE) and alkali-extracted steam-exploded Acacia mangium fiber (AEF) were prepared using 2-roll mill and compression molding. AEF was acetylated (AAEF) to three different wt% gains (WPG) and maleic anhydride grafted polyethylene (MAPE) was used as compatibilizer. Acetylation of AEF (AAEF) did not improve the tensile properties, particularly tensile strength of the composites. Addition of maleic anhydride-grafted polyethylene (MAPE) to either HDPE—AEF or HDPE—AAEF composites improved the composite strength. The effectiveness of MAPE, however, was limited by the weight percent gain (WPG) of AAEF resulting in a decrease in composite strength and stiffness. Sorption kinetics and characteristics of water absorption of the composites immersed in distilled water at room temperature for 30 days were determined and compared. All composites were found to exhibit Fickian diffusion process. Results showed that acetylation and MAPE reduced equilibrium water uptake as well as rate of water absorption (diffusion coefficient) of the composites. A synergistic effect, however, was only observed for the equilibrium water uptake when both were considered in a composite formulation.