Comparative properties of natural rubber vulcanisates filled with defatted rice bran, clay and calcium carbonate

The effects of defatted rice bran (DRB) as a filler for natural rubbervulcanisate on its cure characteristics, mechanical properties and morphology wereinvestigated. The properties of the DRB-filled vulcanisate were also compared with clayfilledand CaCO3-filled vulcanisates. At similar loading level (50 parts per hundred ofrubber), DRB-filled vulcanisate gave the shortest cure time. Clay-filled vulcanisateshowed highest tensile and tear strength followed by DRB-filled vulcanisate. However,CaCO3-filled vulcanisate gave highest rebound resilience while DRB-filled vulcanisateexhibited highest modulus, hardness and abrasion resistance. Scanning electronmicrographs revealed that the morphology of clay-filled vulcanisate was morehomogenous than that of DRB-filled and CaCO3-filled vulcanisates. According to theseobservations, DRB can potentially be used as a cheap and more environment-friendlynatural filler when an improvement in mechanical properties was not so critical.