Studies on influence of silica filler and rice husk ash on the mechanical properties of vulcanized hybrid rubber composite

Abstract

The primary aim of this research work is to develop Nitrile butyl rubber (NBR) based hybrid composites, reinforced with cotton fabric and silica-rice husk ash as filler materials. This study aims to investigate the effect of silica and rice husk ash filler loading on the mechanical and swelling properties. The work studied the filler loading by considering two cases: (a) the silica filler addition 10, 20, 30 and 40 phr (b) addition of equal amount of silica and rice husk ash (RHA) 10, 20, 30 and 40phr. The rubber compound with silica or silica + RHA was prepared using a twin-screw extrusion machine and the cotton fabric was coated with a rubber compound. The specimens are vulcanized at temperature 150 °C under pressure 150 kg/cm2 for 20 min duration. The samples were cut and the morphological and mechanical characteristics such as tensile strength, tear strength and hardness are evaluated as per ASTM standards. The results indicate that a more uniform dispersion of silica and RHA make it a good interfacial adhesion among all the phases of the composite. The tensile strength and hardness were increased with increased loading of the fillers but Elongation at break was decreased. The tear strength was increased due to silica filler loading but silica + RHA filler loading increased the tear strength up to 20phr and beyond this level tear strength was decreased.