Characteristics of methyl silicone oil

Characteristics of methyl silicone oil
Methyl silicone oil has many special properties:

■ Good heat resistance
Because the main chain of the silicone oil molecule is composed of-Si-O-Si-bond, it has a similar structure with inorganic polymer, and its bond energy is very high, so it has excellent heat resistance.

■Good oxidation stability and weather resistance

■ Good electrical insulation
Silicone oil has good dielectric properties, and its electrical properties change little with the change of temperature and frequency. The dielectric constant decreases with increasing temperature, but changes little. The power factor of silicone oil is low and increases with temperature, but there is no rule with frequency. The volume resistivity decreases with increasing temperature.

■ Good hydrophobicity
Although the main chain of silicone oil is composed of polar bond Si-O, the non-polar alkyl group on the side chain is arranged outward to prevent water molecules from entering the interior and play a hydrophobic role. The interfacial tension of silicone oil to water is about 42 dyne/cm. When diffused on the glass, due to the water repellency of silicone oil, a contact angle of about 103 ° is formed, which is comparable to paraffin wax.

■ Small viscosity-temperature coefficient
The viscosity of silicone oil is low and changes little with temperature, which is related to the helical structure of silicone oil molecules. Silicone oil is a kind of oil with the best viscosity-temperature characteristics in various liquid lubricants, and this characteristic of silicone oil is of great significance to damping equipment.

■ High compression resistance
Due to the helical structure of silicone oil molecules and the large distance between molecules, it has high compression resistance. Using this characteristic of silicone oil, it can be used as a liquid spring, and compared with a mechanical spring, the volume can be greatly reduced.

■ Low surface tension
Low surface tension is a characteristic of silicone oil. A low surface tension indicates a high surface activity, and therefore, the silicone oil has excellent defoaming and antifoaming properties, barrier properties from other substances, and lubricating properties.

■ Non-toxic, odorless and physiologically inert
From a physiological point of view, silicone polymers are 1 of the most inactive compounds known. Dimethyl silicone oil is inert to organisms and has no rejection reaction with animal bodies. Therefore, they have been widely used in surgery and internal medicine, medicine, food and cosmetics.

■ Good lubricity
Silicone oil has many excellent properties as a lubricant, such as high flash point, low freezing point, thermal stability, viscosity changes with temperature, no corrosion of metal and rubber, plastic, paint, organic film without adverse effects and low surface tension, easy to spread on the metal surface and other characteristics. In order to improve the steel-to-steel lubricity of the silicone oil, a lubricity additive that is miscible with the silicone oil may be added. The introduction of chlorophenyl groups on the silicone chain or the substitution of trifluoropropylmethyl for dimethyl can greatly improve the lubricating properties of silicone oils.