Type and characteristics of silicaThe reinforcing filler used in silicone rubber mainly refers to synthetic silica,also known as white carbon black.White carbon black is divided into fumed silica and precipitated silica.

　　a,fumed silica

　　The size,specific surface area,surface properties,structure,etc.of the silica particles are related to the ratio of the material gas,the burning rate,and the residence time of the SiO2 core in the combustion chamber.

　　The finer the gas phase white carbon black particles,the larger the specific surface area,the better the reinforcing effect,but the worse the handling performance.On the contrary,its particles are coarser,the specific surface area is smaller,and the reinforcing effect is worse,but the operability is better.

　　Vapor white carbon black is one of the most commonly used reinforcing agents for silicone rubber.The vulcanized rubber which is reinforced by it has high mechanical strength and good electrical properties.Fumed silica can be used in combination with other reinforcing agents or weak reinforcing agents to obtain different requirements.

　　b,precipitated silica

　　The properties of precipitated silica are affected by precipitation conditions such as acidity,temperature,and the like.

　　Compared with the silicone rubber compound reinforced with fumed silica,the rubber reinforced with precipitated silica is slightly lower in mechanical strength,and the dielectric properties,especially the dielectric properties after damp,are poor,but heat aging The performance is better and the cost of the rubber compound is much lower.When the mechanical strength of the article is not critical,the precipitated silica may be used in combination with the fumed silica.