2. methyl vinyl silicone rubber

Due to the introduction of a small amount of vinyl in the macromolecular structure of silicone rubber can greatly improve the vulcanization performance of silicone rubber, so in the current application of silicone rubber, mostly contain vinyl. Methyl vinyl silicone rubber is one of the most versatile silicone rubber, currently in the production of silicone rubber at home and abroad in the dominant position. Because it has unsaturated vinyl on the side chain, its machinability and physical and mechanical properties are better than that of the two base silicone rubber. In addition to the general characteristics of dimethyl silicone rubber, it also has a wide range of temperature, can be in a range of 60 ~ 260℃ to maintain good elasticity, it is easier to vulcanize than dimethyl silicone rubber, has a small compression permanent deformation, good solvent resistance expansion and high pressure steam resistance stability and excellent cold resistance, etc. And because of the use of low activity of peroxide vulcanization, so as to reduce the vulcanization bubbles and poor rubber stability. Therefore, the general use of methyl vinyl silicone rubber can be made of larger thickness of products. Methyl vinyl silicone rubber is the most widely used in silicone rubber varieties, have sprung up in recent years, a variety of high performance and special purpose of silicon rubber, they are mostly based on vinyl silicone rubber, silicone rubber, such as high intensity at the low compression set of silicone rubber, don't need after vulcanization silicone rubber, thermal conductive silicone rubber, silicone and so on. Methyl vinyl silicone rubber in the aviation industry, widely used as gaskets, sealing materials and fragile, shockproof parts of the protective layer; In the electrical industry can be used as advanced insulating materials such as electronic components, dynamic sealing ring of high temperature potentiometer, sealing ring of underground long-distance communication equipment; In medicine, because of the small physiological reaction of methyl vinyl silicone rubber to the human body, it is used as a plastic surgery, artificial heart valve, blood vessels and so on.

3.methyl phenyl vinyl silicone rubber

Methyl phenyl vinyl silicone rubber is in methyl vinyl silicone rubber molecular chain in the introduction of methyl phenyl siloxy chain or diphenyl siloxy chain products.

The introduction of phenyl group to the side group of polysiloxane can greatly reduce the crystallization temperature of the polymer because of the destruction of the structure regularity of dimethylsiloxane, and expand the low temperature application range of the polymer material. Therefore, methyl phenyl vinyl silicone rubber in addition to all the compression of methyl vinyl silicone rubber permanent deformation is small, wide use temperature range, oxidation resistance, weather resistance, shock, moisture and good electrical insulation performance, but also has excellent low temperature resistance, ablative resistance and radiation resistance and other properties. These properties vary with the different content of phenyl in the molecular chain. Generally speaking, the content of phenyl (the ratio of phenyl to silicon atoms) in 5 ~ 10% is called low phenyl silicone rubber. It has unique cold resistance and can still maintain the elasticity of rubber at -70 ~ -100℃. In addition, it has the advantages of methyl vinyl silicone rubber and the cost is not high, so there is a trend to replace methyl vinyl silicone rubber. Phenyl content of 20 ~ 40% when the phenyl silicone rubber has the advantages of methyl vinyl silicone rubber and the cost is not high, so there is a trend to replace methyl vinyl silicone rubber. The phenyl content of 20 ~ 40% is called the phenyl silicone rubber, it has excellent fire resistance characteristics, once the fire can be self-extinguishing. Phenyl content in 40 ~ 50%, high phenyl silicone rubber, it has excellent radiation resistance, resistance to γ -ray 1xI08 roentgen. Generally speaking, with the increase of phenyl content, the rigidity of silicone rubber molecular chain gradually increases, and the low temperature resistance of silicone rubber gradually decreases, but with the increase of phenyl content, the fire resistance and radiation resistance of vulcanized rubber are improved.

Methyl phenyl vinyl silicone rubber is one of the important materials in aerospace industry, cutting-edge technology and other departments of national economy. It can be used for making various molded and extruded products as cold resistant rubber in aviation industry and sealing rings, pads, pipes and bars for ablative, heat aging or radiation resistant parts.