Definition of silicone oil
 
Silicone oil is a polyorganosiloxane with a chain structure of different degrees of polymerization. It is prepared by hydrolyzing dimethyl dichlorosilane with water to obtain a primary polycondensation ring, which is then cracked and distilled to obtain a low-ring compound. The ring, head-capping agent, and catalyst are then combined and telomerized to obtain a mixture of various degrees of polymerization. After removing low-boiling substances by vacuum distillation, silicone oil can be obtained.
 
The most commonly used silicone oil has all methyl groups as organic groups, which is called methyl silicone oil. Other organic groups can also be used to replace some methyl groups in the organic group to improve certain properties of the silicone oil and adapt to various applications. Common other groups include hydrogen, ethyl, phenyl, chlorophenyl, trifluoropropyl, etc. In recent years, organic modified silicone oil has developed rapidly, and many organic modified silicone oils with special properties have emerged.
 
Silicone oil is generally a colorless (or light yellow), odorless, non-toxic, and non-volatile liquid. Silicone oil is insoluble in water, methanol, glycol, and - ethoxyethanol, but miscible with benzene, dimethyl ether, methyl ethyl ketone, carbon tetrachloride, or kerosene. It is slightly soluble in acetone, dioxane, ethanol, and methanol. It has a very low vapor pressure, high flash point and ignition point, and low freezing point. As the number of segments n increases, the molecular weight increases and the viscosity also increases. Therefore, silicone oil can have various viscosities ranging from 0.65 centistokes to millions of centistokes. If you want to produce low-viscosity silicone oil, you can use acidic clay as a catalyst and perform telomerization at 180°C, or use sulfuric acid as a catalyst and perform telomerization at low temperatures to produce high-viscosity silicone oil or viscous substances. Alkaline catalysts can be used for viscous substances.
 
Silicone oil classification
 
According to chemical structure, silicone oil can be divided into methyl silicone oil, ethyl silicone oil, phenyl silicone oil, methyl hydrogen silicone oil, methyl phenyl silicone oil, methyl chlorophenyl silicone oil, methyl ethoxy silicone oil, methyl trifluoropropyl silicone oil, methyl vinyl silicone oil, methyl hydroxyl silicone oil, ethyl hydrogen silicone oil, hydroxyl hydrogen silicone oil, cyanide-containing silicone oil, etc. According to the purpose, it can be divided into damping silicone oil, diffusion pump silicone oil, hydraulic oil, insulating oil, heat transfer oil, brake oil, etc.
 
Silicone oil has excellent heat resistance, electrical insulation, weather resistance, hydrophobicity, physiological inertness, and low surface tension. In addition, it has low viscosity-temperature coefficient and high compressibility. Some varieties also have radiation resistance properties.