Source Year: 2012

Three commercial paraffin waxes (carbon numbers 20-40) and one alkyl-aryl-p-phenylene-diamine antiozonant were mixed individually with natural rubber to produce rubber compounds. The compounds contained a precipitated amorphous white silica nanofiller the surface of which was pre-treated with bis(3-triethoxysilylpropyl-) tetrasulphane (TESPT). The rubber compounds were cured via the tetrasulphane groups of TESPT by adding a sulphenamide accelerator and zinc oxide. The viscosity, cure properties, hardness, tensile strength, elongation at break, stored energy density at break, Youngs modulus, modulus at different strain amplitudes, tear strength and cyclic fatigue life of the rubber vulcanizates were measured. The viscosity, scorch time and rate of cure increased, but the optimum cure time decreased when the waxes and antioxonant were added to the rubber. The highest tensile strength, stored energy density at break, modulus at different strain amplitudes and the longest cyclic fatigue life were measured for the vulcanisate with the antiozonant. The rubber vulcanisate containing one of the waxes had the highest tear strength.