Overview of Basic Characteristics and Applications of Silicone Oil
abstract
Silicone oil, as a type of organic silicon compound with a unique molecular structure, has shown extensive application prospects in multiple industrial fields since the 1940s. This article reviews the basic characteristics of silicone oil, including its viscosity, density and volume, thermophysical properties, chemical stability, etc. It also explores the applications of silicone oil in various fields such as mold release agents, anti sticking agents, smoothing agents, refrigerants, and cosmetics.


keyword
Silicone oil; Basic characteristics; Viscosity; Release agent; cosmetics


1. Introduction
Silicone oil, also known as polysiloxane oil, is a type of organic silicon compound that remains in a liquid state at room temperature. It is mainly composed of silicon atoms and oxygen atoms covalently connected to form a long chain structure, and organic groups (such as methyl, ethyl, phenyl, etc.) are introduced at the chain ends or side chains to improve its performance. Silicone oil has been widely used in various fields due to its excellent chemical stability, heat resistance, insulation, weather resistance, hydrophobicity, and low surface tension.


2. Basic characteristics of silicone oil
2.1 Viscosity characteristics
Silicone oil exhibits the best viscosity temperature stability in liquid lubricants, meaning its viscosity is less sensitive to temperature changes. The sensitivity of viscosity to temperature changes increases in the following order: dimethyl silicone oil, methyl hydrogen containing silicone oil<ethyl methyl silicone oil<low phenyl content methyl phenyl silicone oil<medium phenyl content methyl phenyl silicone oil, trifluoromethyl methyl silicone oil<high phenyl content methyl phenyl silicone oil. The viscosity of silicone oil also increases with the increase of pressure and has high compressibility.


2.2 Density and Volume
The relative density of silicone oil increases with the increase of its molar mass or viscosity, and eventually tends to a constant value. The influence of substituent groups can also cause changes in the relative density of silicone oil, such as the relative density of methylphenyl silicone oil being higher than that of pure dimethyl silicone oil. The temperature also has an impact on the relative density of silicone oil, which decreases regularly with increasing temperature.


2.3 Thermophysical Properties
The thermal expansion coefficient of silicone oil is larger than that of water and mercury, similar to mineral oil, and decreases with the increase of polymerization degree and viscosity of silicone oil. In terms of thermal conductivity, the thermal conductivity of silicone oil is about a quarter of that of water, similar to that of benzene and toluene. In the dimethyl silicone oil series, the thermal conductivity increases with the increase of viscosity, but tends to stabilize after reaching a certain viscosity.


2.4 Chemical stability
Silicone oil exhibits high resistance to climate, ozone, and glow discharge due to the chemical inertness and lack of reactive groups of polydimethylsiloxane. At room temperature, silicone oil exhibits stability against water, air, oxygen, various metals, wood, paper, and plastic, and can also resist corrosion from metal salt solutions, liquid hydrogen, and 3% hydrogen peroxide solutions.


3. Application of silicone oil
3.1 Release agent, anti sticking agent, smoothing agent
Silicone oil, as a release agent, anti sticking agent, and smoothing agent, has a wide range of applications in industries such as rubber, plastic, metal casting, glass, paper, and fiber production. High viscosity silicone oil provides excellent demolding and anti sticking properties, while low viscosity silicone oil has excellent coating properties and surface affinity.


3.2 Refrigerant
The branched siloxane oligomer methyl tris (trimethylsiloxy) silane has been widely studied and applied in the field of refrigerants due to its excellent physical and chemical properties. It has the characteristics of non corrosiveness, non toxicity, high boiling point, and suitability for low-temperature environments.


3.3 Cosmetics
In the field of cosmetics, silicone oil is widely used as a high-quality oily raw material due to its excellent physical and chemical properties. Silicone oil can improve the skin feel of cosmetics, provide a smooth and moisturizing effect, and have good spreading and stability.


4. Conclusion
Silicone oil, as a type of organic silicon compound with unique molecular structure and excellent properties, has shown broad application prospects in multiple industrial fields. In the future, with the continuous advancement of technology and changing demands, the application fields of silicone oil will further expand and deepen.