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 (SNR 10) 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-SNR 10 vulcanizates. The tensile strengths of both VT-filled and CB (N330) filled-SNR 10 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-SNR 10 vulcanizates. The results showed that Velvet tamarind seed shell manifested a reinforcing effect on the SNR 10 compounds but lower than that of CB (N330) filler.

Cure Characteristics and Mechanical Properties of Pineapple Leaf Fibre Filled Natural Rubber

“…Thus, the elongation at break decreased, and the modulus increased. The low elongation at break of the rubber vulcanizates obtained in this study implies that the rubber products would be rigid and are expected to have low hysteresis and heat build-up [17]. The observed decrease in elongation at break of PLF filled natural rubber vulcanizates with filler content is consistent with previously reported works on the variation of elongation at break of natural fibre reinforced rubber with filler content [16] [17] [21].…”

“…with filler content maybe attributed to filler related parameters such as particle size, surface area, filler surface reactivity and also, to the increase in mixing time resulting in the introduction of the filler into natural rubber [31] [32]. Okoh et al [17] who worked on Velvettamarid seed shell and CB filled natural rubber vulcanizates reported that the scorch times of the vulcanizates decreased with increasing filler content.…”

“…The figure shows that the EB of unfilled natural rubber vulcanizate is generally greater than those of filled natural rubber vulcanizates. This can be attributed to the adherence of the PLF into the rubber matrix resulting to stiffening of rubber chains, and subsequent hardening of the matrix leading to reduction in rubber ductility [17]. This leads to lower resistance to breakage.…”

“…Thus, renewable resources of agricultural origin that have been used to compound rubber in-cluded groundnut shell, palm kernel husk, rice husk, coco pod husk and cherry [13] [14] [15] [16]. Similarly, Okoh et al [17] who investigated the use of Velvet tamarind (VT) seed shell filler in compounding natural rubber and standard Nigerian Rubber (SNR 10 ) reported that VT shell filler manifested a reinforcing effect on SNR 10 vulcanizates but the reinforcing potential was lower than that of carbon black.…”

Investigation of eco-friendly cellulosic nanoparticles potential as reinforcement agent in the production of natural rubber composites

“…Similarly, for cotton linter based composites (NR-CLNC) the tensile strength increased from 1.85 to 3.92 MPa when CLNC content was increase from 0 -30 pphr while for carbon black(NR-CB) composites, the tensile strength increased from 1.85 to 4.5MPa for CB content of 0 -30 weight %.Generally, from these data presented the tensile strength increased with increasing weight of cellulosic nanoparticles and carbon black in the rubber matrix, though carbon black gave higher values. This behaviour is manifestation of reinforcement tendencies [15] & [16] which imply that there was a strengthening effect of these particulate materials due to the role they play by imposing restriction on rubber chains molecular rupture and slippage of these chains past each other. Also the nature of predominated interface (rubberrubber, rubber-particles or particle-particle) formed and the interfacial interaction between the rubber phase and the nanoparticulate materials plays a vital role in the reinforcement of rubber matrix [4,14,17], that is the higher the ability of the rubber to spread round the particle surface during processing (good wettability) the higher the stress require to break the physical bonding between the rubber and the particle hence the higher the tensile strength.…”