Xanthate-modified silica as a novel multifunctional additive for properties improvement of natural rubber

Reinforcing agents and accelerators are the most important auxiliaries for rubber industry. In this paper, ceric ammonium nitrate (CAN), for the first time, worked as a catalyst for hydroxyl groups in silica to prepare silica grafted sodium xanthate (SSX), which was used as an in-situ modified multifunctional rubber additive in this work. Compared with sodium isobutyl xanthate (SIBX), SSX has enhanced the initial and final degradation temperatures, achieving the improvement of 103 °C and 277 °C, respectively. Notably, owing to the powerful interaction between each component, SSX can be homogeneously dispersed in the natural rubber (NR) matrix in contrast to the seriously aggregated silica. Meanwhile, NR/SSX composites exhibited superior curing properties and showed an increase of 29.1% and 33.4% in the tensile strength and tear strength , respectively, compared to that of traditional 2-mercaptobenzothiazole (MBT) system. Since high-performance rubber composites can be obtained by introducing SSX, we believe that this work can provide a novel and facile approach to prepare natural silicate minerals-based vulcanization accelerators.