Abstract
Nanosilica was ssynthesized by acid hydrolysis of sodium silicate using dilute hydrochloric acid. The ssynthesized silica was scharacterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The particle size of silica was calculated to be 13 nm from XRD results. This synthetic nanosilica was used in place of hydrated silica in an HRH (hexamethylenetetramine, resorcinol, and silica) bonding system for a styrene–butadiene rubber (SBR)/nylon-6 short fibre composite. Nanosilica was also used as reinforcing filler in an SBR/nylon-6 short fibre hybrid composite. The cure characteristics and mechanical properties of the hybrid composites were evaluated. Minimum torque, maximum torque, and cure rate of the hybrid composites increased with silica loading. Cure time decreased with fibre loading and increased with silica content. Scorch time also decreased with fibre loading. The volume fraction of rubber in a solvent-swollen sample increased with nanosilica. Nanosilica in the rubber composites also improved the tensile strength, modulus, and tear strength to a greater extent than the conventional silica. Abrasion loss and hardness were also better for the nanosilica composites. Resilience and compression set were adversely affected. The composites showed anisotropy in mechanical properties.