The reinforcing potentials of <i>Velvet tamarind</i> seed shell as filler in natural rubber compounds

Abstract

This work focused on the development of a reinforcing filler from renewable natural plant resources as part of the ongoing search for environmental friendly fillers that will substitute synthetic reinforcing fillers such as carbon black and silica in rubber manufacturing. The cure characteristics, physico-mechanical and equilibrium swelling properties of natural rubber, Standard Nigerian Rubber (SNR10) vulcanizates separately filled with commercial grade carbon black (CB), N330 and pulverized natural plant material, Velvet tamarind (VT), seed shell were investigated. The results of the analyses showed that the scorch and cure times decreased while the maximum torques increased with increasing filler loading for both filled-SNR10 vulcanizates. The tensile strengths of both VT-filled and CB (N330) filled-SNR10 vulcanizates increased to 30 phr and 40 phr respectively and decreased with increasing filler loading. The modulus at 100% strain, specific gravity, abrasion resistance and hardness increased while elongation at break, equilibrium swelling and rebound resilience decreased with increasing filler loading for both filled-SNR10 vulcanizates. The results showed that Velvet tamarind seed shell manifested a reinforcing effect on the SNR10 compounds but lower than that of CB (N330) filler.Keywords: Natural rubber, fillers, reinforcement and vulcanizate properties.