Silica is called hydrated silica, and can also be called colloidal silica. It mainly refers to precipitated silica and fumed silica. Its chemical formula can be expressed as Si02. nH20, a white amorphous structure powder, is not toxic. The silica has a porous structure, large specific surface area, high dispersibility, light weight, and excellent physical and chemical properties such as good chemical stability, high temperature resistance, non-combustion, and good electrical insulation.

The modified white carbon black almost inherits all the superior properties of ordinary fumed silica, and due to its special hydrophobicity, the application field is greatly expanded. Among the many hydrophobic products, hydrophobic white carbon black modified by DMDC is the most widely used, such as Degussa's Aerosil-R 972, which has the tendency of preventing material agglomeration and improving the fluidity of powder materials. It can be used for plastic powder, Fire extinguishing powder, peroxides, cosmetic powders, powder coatings and other fields to improve product processability, applicability and storage. Generally, amorphous silica has a refractive index of 1.46, which has good optical properties. Since its refractive index is similar to that of rubber, when silica is used as a reinforcing material for silicone rubber, silicon with good transparency can be prepared. rubber.

In order to obtain silicone rubber with better product performance, many people have set their sights on the modification of silica. There are a lot of silicon hydroxyl groups on the surface of silica. Therefore, it is easy to agglomerate when silica is added to silicone rubber. By making the fumed silica from hydrophilic to hydrophobic, the compatibility of the silica with the polymer can be improved. In short, it is the fact that silica cannot be dispersed in silicone rubber and does not play its due role, thereby eliminating or reducing the amount of hydroxyl on the surface of silica.