Effects of antioxidant functionalized silica on reinforcement and anti-aging for solution-polymerized styrene butadiene rubber: Experimental and molecular simulation study

A new type of antioxidant functionalized silica (SiO2-g-MC) was prepared by grafting antioxidant N-(4-aniline phenyl) maleic imide (MC) onto the surface of silica via γ-mercaptopropyl trimethoxysilane (KH590). The effects of SiO2-g-MC on reinforcement and anti-aging for solution-polymerized styrene butadiene rubber (SSBR) were investigated by experimental and molecular simulation methods. It was found that the reinforcement of SiO2-g-MC was much more effective than that of the neat silica (SiO2) in SSBR matrix due to well-dispersion and strong interfacial interaction between SiO2-g-MC and SSBR. Compared with KH590 modified silica (SiO2-KH590) and SiO2, SiO2-g-MC had better vulcanization behavior and could greatly improve thermo-oxidation resistance of SSBR composite. Furthermore, grafting MC onto the surface of silica could not only restrain the migration of free MC, but also reduce the negative influence of free MC on cross-linking density of SSBR composite. Therefore, SiO2-g-MC/SSBR composite exhibited more preeminent mechanical properties than SiO2-KH590/MC/SSBR composites during the thermo-oxidation aging process. These results indicated that SiO2-g-MC could be used as a functional filler for the preparation of high performance SSBR composites, and moreover, the theoretical molecular simulation process can help us gain a better insight into the structure-property relationship for SSBR composite.