Silicone oil is used as high-grade lubricating oil, shock-absorbing oil, and insulating oil.
Silicone oil (also known as silicone) is a linear poly siloxane mixture produced through processes such as hydrolysis, cracking, and polymerization of dimethyl dichlorosilane. It is a synthetic material. This substance has a colorless (or light yellow) appearance, no odor, is non-toxic, and is not volatile. It exhibits a liquid-like property with a wide viscosity range (0.65 centistokes to over 100,000 centistokes), and possesses characteristics such as high resistance to high and low temperatures (thermal stability up to 250°C), antioxidant properties, low surface tension, and electrical insulation. Silicone oil is classified into two types based on its application: industrial dimethyl silicone oil and daily-use silicone oil. The main chain of the molecule is composed of the Si-O-Si structure. This material is widely used in the production of high-grade lubricating oil, shock-absorbing oil, insulating oil, defoamer, and release agent. It is also applied in fields such as electronic encapsulation and insulation, motor and electrical appliance insulation, textile finishing, automotive damping, medical and daily chemical, surface treatment, plastic and rubber additives, and in waste gas biological treatment. 
Silicone oil is usually a transparent, colorless, odorless, tasteless and non-toxic oily liquid. Its viscosity range is extremely wide, ranging from 0.65 cst to 1,000,000 cst or even 2,000,000 cs, and the viscosity remains constant over a wide temperature range. 
Silicone oil has excellent thermal stability, with a thermal stability of up to 250°C, a high flash point, low volatility, and low vapor pressure. It also has excellent electrical insulation properties, resistance to electric arcs and electric corona, and stable dielectric performance. 
Silicone oil has a low surface tension and is easy to spread on the surface of objects; it can be dissolved in non-polar solvents but not in water or polar solutions. The solubility can be adjusted through chemical modification. At 25°C, its density is approximately 0.963 g/mL and its refractive index is approximately 1.403. 
Silicone oil has stable chemical properties and excellent antioxidant and anti-hydrolysis capabilities. It does not corrode metals. Its main molecular chain is composed of repeated Si-O bonds, and the side groups are connected with organic groups. According to the functional groups and structure, it can be classified into linear and branched types. 
The production of silicone oil (silicone rubber) can be carried out using a new solid-phase catalyst process for the preparation of low-molecular-weight polysiloxanes. This process replaces the traditional catalyst, concentrated sulfuric acid, with a new highly efficient solid-phase catalyst to produce linear hydrogen-containing polysiloxanes (hydrogen-containing silicone oil) and end-hydroxyl polysiloxanes (hydroxyl silicone oil). The specific steps are as follows: using petroleum ether as the solvent and hydrochloric acid as the medium, the monomethyl hydrogen dichlorosilane and trimethyl chlorosilane are co-hydrolyzed at a temperature below 25℃. The hydrolyzate is washed, separated, and dried, and then catalyzed by the new solid-phase catalyst for rearrangement to carry out copolymerization reactions. Finally, after filtration and solvent removal treatment, the product is obtained. 
Silicone oil mainly consists of two types: industrial-grade dimethyl silicone oil and the commonly used silicone oil for daily use. Additionally, based on the different organic groups in the side chains, silicone oil can be further classified into types such as methyl silicone oil, ethyl silicone oil, methyl phenyl silicone oil, and acrylate-containing silicone oil, among which methyl silicone oil is the most commonly used. 
Silicone oil is applied in many fields. Among various types of silicone oil, methyl silicone oil is the most widely used and is the most common variety of silicone oil. The next is methyl phenyl silicone oil. Various functional silicone oils and modified silicone oils are mainly used for specific purposes. 


Silicone oil is widely used in various industrial and civilian fields due to its excellent electrical insulation properties, high temperature resistance, low surface tension, chemical inertness, and physiological inertness. Its main applications include being used as a textile softener, an electronic and electrical insulation and packaging material, shock-absorbing damping oil, release agent, defoamer, lubricant, surface treatment agent, performance additive, and environmental treatment emulsifier, etc. 
It is commonly used as lubricating oil, shock-absorbing oil, insulating oil, defoamer, release agent, polishing agent and vacuum diffusion pump oil, etc. Methyl silicone oil is the most commonly used. In addition, there are ethyl silicone oil, methyl phenyl silicone oil, and acrylonitrile-containing silicone oil, etc. 
Silicone oil is also applied in environmental treatment. Research has shown that it has an enhancing effect on the biological treatment of organic waste gas. When treating toluene waste gas using a biological drip filter tower, adding silicone oil can significantly improve the solubilization effect of toluene, and has no negative impact on the degradation activity of microorganisms. Under the same experimental conditions, the removal efficiency of toluene by the biological drip filter tower with silicone oil added can be approximately 10% higher than that of the ordinary biological drip filter tower.