The basic structural unit of silicone rubber products is composed of silicon-oxygen chains, and the side chains are connected with other organic groups through silicon atoms. Therefore, the structure of organic silicon products contains both "organic group" and "inorganic structure". This special composition and molecular structure makes it integrate the characteristics of organic matter and the functions of inorganic matter. Compared with other macromolecule materials, the most outstanding properties of silicone products are:
1. Temperature Resistance
Silicone products are mainly composed of silicon-oxygen (Si-O) bond. The bond energy of C-C bond is 82.6 kcal/molecule. The bond energy of Si-O bond is 121 kcal/molecule in silicone. Therefore, the thermal stability of silicone products is high, and the chemical bonds of silicone molecules continue to split and not decompose at high temperature (or irradiation). Silicone can not only withstand high temperature, but also low temperature. It can be used in a wide temperature range. Both chemical and physical mechanical properties are less affected by temperature.
2. Weatherability
The main chain of organosilicon products is-Si-O-, and there is no double bond, so it is not easy to be decomposed by ultraviolet light and ozone. Silicone has better thermal stability, radiation and weather resistance than other polymer materials. Silicone can be used in natural
environment for decades.
3. Electrical Insulation Performance
Silicone products all have good electrical insulation properties. Their dielectric loss, voltage resistance, arc resistance, corona resistance, volume resistance coefficient and surface resistance coefficient are among the top insulating materials, and their electrical properties are little affected by temperature and frequency. Therefore, they are a kind of stable electrical insulation materials, which are widely used in the electronic and electrical industries. In addition to excellent heat resistance, organosilicon also has excellent water repellency, which is the guarantee of high reliability of electrical equipment in wet condition.
4. Physiological inertia
Polysiloxanes are one of the most inactive compounds known. They are very resistant to biological aging, have no rejection reaction with animals, and have good anticoagulant properties.
5. Low surface tension and low surface energy
The main chain of organosilicon is very flexible. The intermolecular force of organosilicon is much weaker than that of hydrocarbons. Therefore, the viscosity of organosilicon is lower than that of hydrocarbons with the same molecular weight, the surface tension is weaker, the surface energy is smaller and the film forming ability is stronger. This low surface tension and low surface energy are the main reasons for its application in many ways: hydrophobic, defoaming, foam stabilization, anti sticking, lubrication, polishing and other excellent properties.
