Mechanical properties of sisal/oil palm hybrid fiber reinforced natural rubber composites

Natural rubber is reinforced with untreated sisal and oil palm fibers chopped to different fiber lengths. The effects of concentration and modification of fiber surface in sisal/oil palm hybrid fiber reinforced rubber composites have been studied. Increasing the concentration of fibers resulted in reduction of tensile strength and tear strength, but increased modulus of the composites. Composites were prepared using fibers treated with varying concentrations of sodium hydroxide solution and for different time intervals. The vulcanisation parameters, processability characteristics, and stress-strain properties of these composites were analysed. The rubber/fiber interface was improved by the addition of a resorcinol-hexamethylene tetramine bonding system. The reinforcing property of the alkali treated fiber was compared with that of untreated fiber. The extent of fiber alignment and strength of fiber-rubber interface adhesion were analysed from the anisotropic swelling measurements. (C) 2003 Elsevier Ltd. All rights reserved.