When adding fumed silica to RTV silicone rubber, one must pay attention to the degree of dispersion in the polymer. After the dispersion process is stopped, the fumed silica that has reached the optimal dispersion condition will form a complete network in the system. It has high viscosity and excellent thixotropic properties. When the rubber compound is subjected to shear force, the viscosity is greatly reduced. With certain fluidity, the viscosity will quickly recover after the shear force is released; if the dispersion is not enough or excessively dispersed, only a part of the fumed silica will be formed, resulting in lower viscosity and poor thixotropic properties. In transparent systems, the higher the transmittance, the better the dispersion of silica. Under the same dispersion conditions, fumed silica products with a large specific surface area generally have better transparency.