Methyl silicone oil is generally colorless, tasteless, non-toxic and non volatile liquid, insoluble in water, methanol and glycol, it is miscible with benzene, dimethyl ether, carbon tetrachloride or kerosene, slightly soluble in acetone, dioxane, ethanol and butanol.
Because the intermolecular force of methyl silicone oil is small, it has helical molecular chain and free rotation of organic groups, and it has excellent spreading performance, lubricity, high and low temperature resistance, weather resistance, radiation resistance, high flash point, low surface tension and physiological inertia, etc., and is widely used in daily chemical, mechanical, electrical, textile, coating, medicine and food industries.
Methyl silicone oils have many special properties:
Because the main chain is composed of -Si-O-Si-bond, which is similar to inorganic polymer and has high bond energy, it has excellent heat resistance.
Silicone oil has excellemt dielectric properties, and its electrical characteristics change little with the change of temperature and cycle number. The dielectric constant decreases with the increase of temperature, but the change is little. The power factor of silicone oil is low, which increases with the increase of temperature, but has no regular change with frequency. The volume resistivity decreases with the increase of temperature.
Although the main chain of silicone oil is composed of Si-O, the non-polar alkyl groups on the side chain are oriented outward to prevent water molecules from entering into the interior and play a hydrophobic role. The interfacial tension of silicone oil to water is about 42 dyne/cm. When the silicone oil diffuses on the glass, the contact angle of about 103° is formed due to the water repellency of silicone oil, which is comparable to that of paraffin wax.