The effect of bio-based ingredients in isoprene rubber: A biomimetic approach to improve the dispersion of silica

Abstract

The effect of phospholipid, sorbitol, and their mixed combination in silica dispersion for a fixed loading of silica and CB ratio (30/20) in isoprene rubber matrix is realized and compared with the effect of DPNR composite as well. The higher loading of silica in tyre tread compound reduces the rolling resistance of a tyre, implicating a step towards a green approach and sustainability. Herein, the bio-based ingredients were used to enhance the dispersion of silica significantly which is otherwise a challenging task in rubber industries. Among them, the phospholipid embedded compound was proved as an ideal vulcanizate for tyre tread application based on its performance. The developed composite exhibited superior elastic storage modulus, low Tan δ at 70 °C (rolling resistance), and significant improvement in key properties (i.e., Tan δ at 0 °C, heat build-up, and abrasion resistance). Moreover, a homogenous dispersion of silica filler was evidenced by morphological analysis (FE-SEM, TEM, and AFM) and a low Payne effect from the dynamic strain sweep. However, the combination of sorbitol and phospholipid evidenced an interaction between them proved from FTIR and 1H NMR analysis, which displayed an improvement in many vital properties but due to its inferior mechanical strength and Tan δ at 0 °C, it could not be preferred as an ideal compound. As far as the tyre tread application is concerned, the presence of phospholipid made the compound persistent in terms of its overall performance, especially a significant improvement in Tan δ at 0 °C than the other compounds.