Restricted accessResearch articleFirst published online 2026
Effect of partial replacement of silica with surface-treated and silver-grafted coir fiber on the physico-mechanical properties of coir fiber-reinforced rubber composites
Coir fiber (CF) used as a filler in rubber composites (RC) offers a distinct set of properties that can enhance composite performance. This study investigates the improvement of rubber composite properties achieved by partially replacing silica with differently treated short coir fibers: alkali treated coir fiber (ATCF) and silver nanoparticles grafted onto alkali-treated coir fiber (AgATCF). XRD analysis showed an approximately 4% higher crystallinity index for AgATCF compared to ATCF. FTIR spectroscopy confirmed the effective removal of lignin and hemicellulose in ATCF, while TGA showed higher thermal stability for both ATCF and AgATCF. Partial replacement of silica filler with 5 phr of novel AgATCF improved the tensile strength, tear strength, and modulus of the rubber composite by approximately 6%, 7%, and 23%, respectively, compared to ATCFRC. In addition, the AgATCF reinforced rubber composite exhibited a 35% reduction in compression set and a 17% decrease in water absorption, along with improved hardness, compared to ATCF-reinforced rubber composites. These results demonstrate that partial silica replacement with novel AgNP-grafted coir fiber provides high reinforcement efficiency, highlighting the potential of hybrid filler in reinforced rubber composites for demanding applications such as conveyor belts and flexible products used in cold environments.
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