Effect of chemical modification on properties of hybrid fiber biocomposites

The effects of chemical modification of fiber surface in sisal–oil palm reinforced natural rubber green composites have been studied. Composites were prepared using fibers treated with varying concentrations of sodium hydroxide solution and different silane coupling agents. The vulcanisation parameters, processability conditions and tensile properties and swelling characteristics of these composites were analysed. The fiber reinforcing efficiency of the chemically treated biocomposites was compared with that of untreated composites. The extent of fiber alignment and strength of fiber–rubber interfacial adhesion was analysed from the swelling measurements. Composites containing chemically treated fibers were found to possess enhanced mechanical properties. The hardness and abrasion resistance of the untreated and treated composites were also analyzed. Surface characterization of treated and untreated sisal fibers by XPS showed the presence of numerous elements on the surface of the fiber. The fracture mechanism of treated and untreated fiber reinforced rubber biocomposites was investigated from SEM studies.