Treatment of natural rubber with bio-based components: A green endeavor to diminish the silica agglomeration for tyre tread application

Production of green tyres by replacing carbon black (CB) with silica in natural rubber (NR) has gathered attention in automotive industries in the recent past. Incorporating high dosages of silica in NR by solid-state mixing is a huge challenge. In green tyre technology, abrasion resistance index (ARI) is crucial alongside rolling resistance, wet grip, and heat build-up. In this study, two new non-silane coupling agents have been introduced to replace bis(3-Triethoxysilylpropyl)disulfide (TESPD). Amidst them, chemical-A (sorbitol) as an alternate coupling agent of TESPD effectively achieved most properties except ARI. Hence, the naturally obtainable sustainable and cost effective chemicals A and B (B-sorbic acid) are incorporated during mastication, acting as blocking agents. Consequently, chemical-A as a blocking agent executed remarkable improvement in crucial properties, including ARI. Furthermore, the optimization study of sorbitol is accomplished based on curing time, FTIR, and XPS analysis. Subsequently, using similar quantity (0.5 phr) sorbitol in silica-CB filled NR compound evidenced better performances as tyre tread compound.