Property enhancement of acrylonitrile butadiene rubber/bagasse ash composites by tannic acid

Bagasse ash (BA) is an agricultural waste obtained from power plants using sugarcane bagasse as an energy source. Although BA is successfully used as a building material, its application in the polymer industry remains challenging due to the lack of surface reactivity. In this study, BA was purified and named PBA before being incorporated into acrylonitrile butadiene rubber (NBR). Tannic acid (TA), a naturally occurring plant polyphenol, was used as a surface-modifying agent for improved interfacial interaction. The effect of TA content on the properties of PBA-filled NBR was investigated. The results showed that the presence of TA resulted in cure retardation, i.e., the scorch time, cure time, and activation energy of the vulcanization reaction increased with increasing TA content. However, the increase in TA content enhanced a rubber-filler interaction, as evidenced by the considerable increase in bound rubber content. Such an enhancement resulted in the improvement of certain mechanical properties, including hardness, modulus, tensile strength, and tear strength. This research showed that tannic acid can be used as a surface-modifying agent in NBR/PBA composites.