Silicone rubber polymer molecule is a chain structure connected by Si-O (silicon oxygen) bond. Its main composition is high molar mass linear polysiloxane. Because the Si-O-Si bond is the basic bond type, the silicon atom is mainly connected to the methyl group, a very small amount of unsaturated groups are introduced into the side chain, the intermolecular force is small, the molecules are in a helical structure, and the methyl groups are arranged outward and can rotate freely, so that the silicone rubber has better heat resistance, electrical insulation and chemical stability than other ordinary rubber. The typical silicone rubber, polydimethylsiloxane, has a helical molecular configuration with small intermolecular force, so it has good resilience. At the same time, the formaldehyde group pointing outside the helix can rotate freely, so the silicone rubber has unique surface properties, such as hydrophobicity and surface anti viscosity.


Heat resistance: silicone rubber has much better heat resistance than ordinary rubber. It can be used almost forever at 150 degrees without performance change; It can be used continuously for 10000 hours at 200 degrees; It can also be used for a period of time at 350 degrees. It is widely used in occasions requiring heat resistance: hot water bottle sealing ring, pressure cooker ring and heat-resistant handle


Cold resistance: the delay of ordinary rubber is - 20 ℃ ~ - 30 ℃, that is, silicone rubber still has good elasticity at - 60 ℃ ~ - 70 ℃. Some silicone rubber with special formula can also withstand extremely low temperature. Low temperature sealing ring


Weather resistance: ordinary rubber degrades rapidly under the action of ozone generated by corona discharge, while silicone rubber is not affected by ozone. And its physical properties change only slightly under ultraviolet and other climatic conditions for a long time. Sealing materials for outdoor use


Electrical properties: silicone rubber has high resistivity and its resistance remains stable in a wide temperature and frequency range. At the same time, silicone rubber has good resistance to high voltage corona discharge and arc discharge. High voltage insulator, TV high voltage cap, electrical parts, others


Conductivity: when conductive filler (such as carbon black) is added, silicone rubber has conductive contact points of keyboard


Thermal conductivity: when some thermal conductive fillers are added, the silicone rubber has thermal conductivity. Heat sink heat conductive gasket heat conductive roller of copier and fax machine


Radiation resistance: the radiation resistance of silicone rubber containing phenyl is greatly improved, such as electrically insulated cables, connectors for nuclear power plants, etc


Flame retardancy: silicone rubber is combustible, but when a small amount of flame retardant is added, it has flame retardancy and self extinguishing; And because the silicone rubber does not contain organic halides, it does not emit smoke or toxic gas during combustion. Various occasions with strict fire prevention


Air permeability: silicone rubber film has better air permeability than ordinary rubber and plastic waxing film. Another feature is that it has strong selectivity for different air permeability. Gas exchange membrane medical products artificial organs