The Effect of Fumed Silica Loading on the Thermal Stability of Fluorosilicone Composites

The effect of fumed silica loading on the thermal stability and mechanical properties of fluorosilicone (FVMQ) rubber was investigated. The distribution of fumed silica inside FVMQ was characterized using scanning electron micros-copy, and the thermal stability of composites was evaluated using thermogravimetric analysis and by the changes in mechanical performance during thermo-oxidative aging. The function mechanism of fumed silica was studied by Fourier transform infrared spectroscopy. The results show that with increasing silica content, the crosslink density of composites, the modulus at 100%, and tensile strength also increased, whereas the elongation at break decreased. Furthermore, increas-ing the silica content of composites increased the initial decomposition temperature (Td) and residual weight of the com-posite after exposure to nitrogen. In addition, the thermal oxidative aging experiment demonstrated improved aging resistance of the FVMQ composites, including lower change in tensile strength, elongation at break, and modulus at 100%.