Mechanical properties, thermal degradation and natural weathering of high density polyethylene/rice hull composites compatibilized with maleic anhydride grafted polyethylene

The influences of rice hull (RH) contents and particle sizes on the mechanical, physical, thermal and morphological properties of high density polyethylene (HDPE)/RH composites were investigated in the current research. Further study was conducted by incorporating maleic anhydride grafted polyethylene (MA-g-PE) to improve the interfacial adhesion between HDPE and RH. Experimental results indicated that the flexural and the tensile strengths were increased upon raising the silica-rich RH contents. With the addition of RH, the composites became brittle as was reflected by the lower impact strength. An improvement of all the flexural, tensile and impact strength was evident when the MA-g-PE was added in all levels. SEM micrographs revealed some RH pulled-out and numerous interfacial cavities occurred within the untreated HDPE/RH composites. With the presence of the compatibilizer, the interfacial adhesion was significantly improved. Lower water absorption was found when MA-g-PE was added in all compositions. Under UVexposure, the colors of the composites found to paler shade.