Effect of SiO₂ surface modification on the filler-reinforced interfaces in SiO₂-filled functional styrene butadiene rubber composites

Silicon dioxide (SiO2), commonly known as silica, the surface is modified using bis(3-triethoxysilylpropyl) tetrasulfide, also known as (Si69) and polyethylene glycol (PEG). A series of composites are prepared by mixing general solution styrene butadiene rubber (GSSBR) and polyethylene oxide-functionalized solution styrene butadiene rubber (FSSBR) with unmodified and modified SiO2. A comparative analysis is conducted using various characterization techniques to evaluate the performance of different composites regarding rubber-filler dispersion, thermal and dynamic mechanical properties. Field emission scanning electron microscopy demonstrates that FSSBR/SiO2@Si69 facilitates a more uniform and well-dispersed distribution of silica particles, improving the compatibility between the rubber-filler matrix and reducing the size of particle aggregates. Thermogravimetric analysis shows that composites GSSBR/SiO2@PEG and GSSBR/SiO2@Si69 + PEG and FSSBR/SiO2@Si69 possess superior thermal stability with minimal weight loss. According to the rubber process analyzer (RPA) analysis, FSSBR/SiO2@Si69 results in significantly reduced Payne effect values, indicating improved dispersion of the rubber-filler mixture. These findings suggest that the simultaneous functionalization of SSBR and surface modification of SiO2 effectively enhance the interaction between filler and rubber.