What are the excellent properties of silicone oil that we don’t know?
Many products in life are synthesized from chemical products. These products are using their advantages for our use. Silicone oil usually refers to a linear polysiloxane product that maintains a liquid state at room temperature. It is generally a colorless (or light yellow), odorless, non-toxic, non-volatile liquid, insoluble in water, methanol, ethylene glycol, and compatible with benzene. , Dimethyl ether, carbon tetrachloride or kerosene are mutually soluble, slightly soluble in acetone, dioxane, ethanol and butanol. Let me introduce the excellent properties of silicone oil.
One. good heat resistance
Since the main chain of the polysiloxane molecule is composed of -Si-O-Si- bonds, it has a structure similar to that of inorganic polymers, and its bond energy is very high, so it has excellent heat resistance.
Two. Good oxidation stability and weather resistance
Three. good electrical insulation
Silicone oil has good dielectric properties, and its electrical characteristics change little with the change of temperature and frequency. The dielectric constant decreases with increasing temperature, but the change is small. The power factor of silicone oil is low, and it increases with the temperature rise, but there is no rule with the frequency change. The volume resistivity decreases as the temperature rises.
Four. good hydrophobicity
Although the main chain of silicone oil is composed of the polar bond Si-O, the non-polar alkyl group on the side chain is oriented outwards, preventing water molecules from entering the interior and playing a hydrophobic role. The interfacial tension of silicone oil to water is about 42 dyne/cm. When spreading on the glass, due to the water repellency of silicone oil, a contact angle of about 103oC is formed, which is comparable to paraffin wax.
Five. the viscosity-temperature coefficient is small
The viscosity of silicone oil is low, and it changes little with temperature, which is related to the helical structure of silicone oil molecules. Silicone oil has the best viscosity-temperature characteristics among various liquid lubricants. This characteristic of silicone oil is of great significance to damping equipment.
Six. high compression resistance
Due to the helical structure characteristics of the silicone oil molecules and the large distance between the molecules, it has high compression resistance. Utilizing this characteristic of silicone oil, it can be used as a liquid spring. Compared with a mechanical spring, the volume can be greatly reduced.
Seven. low surface tension
Low surface tension is the characteristic of silicone oil. Low surface tension means high surface activity. Therefore, silicone oil has excellent defoaming and anti-foaming properties, isolation properties from other substances, and lubricating properties.
Eight. non-toxic, tasteless and physiologically inert
“From a physiological point of view, silicone polymers are one of the most inactive compounds known. Simethicone is inert to organisms and has no rejection reaction with animal bodies. Therefore, they have been widely used in departments such as surgery and internal medicine, medicine, food and cosmetics.
Nine. good lubricity
Silicone oil has many excellent properties as a lubricant, such as high flash point, low freezing point, thermal stability, small viscosity change with temperature, no corrosion of metals, no adverse effects on rubber, plastics, coatings, organic paint films, and low surface tension. It is easy to spread on the metal surface and other characteristics. In order to improve the steel-to-steel lubricity of silicon oil, lubricity additives that can be miscible with silicon oil can be added. Introducing a chlorophenyl group on the siloxane chain or substituting a trifluoropropylmethyl group for a dimethyl group can greatly improve the lubricating properties of the silicone oil.
Ten. Chemical properties
Silicone oil is relatively inert because the Si-C bond is very stable. But strong oxidants are easy to interact with, especially at high temperatures. Silicone oil reacts violently with chlorine gas, especially for methyl silicone oil. Sometimes there will be an explosive reaction. The Si-O bond is easily broken by strong bases or acids. Concentrated sulfuric acid reacts quickly at low temperatures, breaking the siloxane chain and attaching it to it. In this regard, silicone oils with high alkane groups and phenyl groups are more stable, but concentrated sulfuric acid will break the benzene-silicon bond of the phenyl groups and release benzene.
Post time: Aug-23-2021