Sawdust powder filled natural rubber composites were prepared by incorporation of different loadings (20100 phr) of sawdust powder fillers. Two series of composites were studied, i.e. composites with and without maleic anhydride grafted natural rubber (NRgMAH). Grafting of maleic anhydride onto the natural rubber was done prior to compounding using an internal mixer at 145°C. The curing characteristics, hardness property and tensile properties of the composites were studied. Results indicate that the scorch time and cure time decrease with increasing filler loading whereas the maximum torque exhibit an increasing trend. Increasing sawdust powder content also increases the tensile modulus and shows superior hardness property over than 80 shore A, but the tensile strength and elongation at break decrease. As the filler loading increases, the rubberfiller interactions of the composites decrease. The interfacial interaction of sawdust powder filler and natural rubber matrix was enhanced by the addition of NRgMAH, as exhibited by the fracture surfaces of the composites using a Scanning Electron Microscope (SEM) and rubberfiller interaction studies. The presence of NRgMAH has prolonged the curing time and scorch time and enhanced the tensile properties.
Natural Rubber Composites Filled with Cereals Straw Modified with Acetic and Maleic Anhydride: Preparation and Properties