Mechanical properties of rice husk and rice husk ash filled maleated polymers compatibilized polypropylene composites

This study compares the mechanical properties of rice husk (RH) and rice husk ash (RHA) filled polypropylene (PP) composites and the effects of ethylene-acrylic-ester-maleic anhydride (E-AE-MA) and PP-g-maleic anhydride (MAPP) as compatibilizer. In this study, PP/RH and PP/RHA composites were blended at the ratios of 85/15 wt% and compatibilizers at four parts per hundred each, via melt extrusion in a twin-screw extruder prior to injection molding. Mechanical tests were tensile, flexural and impact tests. A morphological study was conducted by scanning electron microscope (SEM). Results show that PP/RHA composite exhibited a 4% significant increase in tensile strength compared to PP/RH composite (p < 0.05) while, PP-RH composite increased significantly by 5 and 3% in flexural and impact strength compared to PP-RHA composite (p < 0.05). MAPP increased significantly the flexural strength of PP-RH and PP-RHA composites by 23 and 21% (p < 0.05) compared to E-AE-MA. PP-RHA-MAPP composite increased significantly the impact strength by 18% compared to PP/RHA/E-AE-MA composite (p < 0.05). There was no significant difference in impact strength between PP/RH/MAPP and PP/RH/E-AE-MA composites (p >= 0.05). Overall results indicate that RH imparts better reinforcing effect in PP composite than RHA, while MAPP is a better compatibilizer. SEM study indicates that both compatibilizers improved the filler-matrix interfacial adhesion.