Methyl vinyl Phenyl Polysiloxane rubber is referred to as phenyl silicone rubber. Phenyl silicone rubber refers to high molecular weight lines containing phenyl siloxane or methyl phenyl siloxane in the main chain. type polysiloxane. After being mixed with fillers, organic peroxide vulcanizing agents and processing aids, it can be heated and vulcanized to become elastomers. Phenyl silicone rubber has small deformation under water compression except for methyl vinyl silicone rubber, and has a wide operating temperature range and is resistant to water. In addition to aging, shock resistance, moisture resistance and excellent electrical insulation properties, it also has excellent low temperature resistance, shock absorption, ablation resistance and radiation resistance. Due to the introduction of phenyl groups into the molecular structure, the regularity of the siloxane molecular structure is destroyed, the crystallinity of the polymer is reduced, and the cold resistance is improved.

1. Classification

1. When the phenyl content is 5-15% (the ratio of phenyl to silicon atoms), it is generally called low phenyl silicone rubber. At this time, the hardening temperature of the rubber drops to (-115 °C), which makes it have better low temperature resistance. , high damping and other characteristics, it still has flexible elasticity at -100 ℃. With the increase of phenyl content in phenyl silicone rubber PVMQ, the rigidity of molecular chain increases, and its crystallization temperature increases instead.

2. When the phenyl content is 15-25%, it is generally called medium phenyl silicone rubber, which is resistant to ablation and has the characteristics of flame resistance.

3. When the phenyl content is above 30%, it is generally called high phenyl silicone rubber, which has excellent radiation resistance. Phenyl silicone rubber is used in applications requiring low temperature resistance, ablation resistance, high energy radiation resistance, heat insulation, etc. With anti-radiation properties (anti-neutron radiation, such as gamma rays), it is used in nuclear power plants, reactors, radioactive sewage treatment plants. Lead powder can be added to phenyl silica gel (the role of lead, reducing weight), and it can be made into silicon-grade leather or silica gel sheet and put into clothes, which can be made into protective clothing for radiation protection purposes. It can also be made into a flexible radiation shield, or block the target gap with silicone mud.

Medium phenyl and high phenyl silicone rubbers are difficult to process. The physical and mechanical properties are poor, and the production and application are limited. The medium phenyl silicone rubber has excellent cold resistance. Once it catches fire, it can be self-extinguishing. The high phenyl silicone rubber has excellent radiation resistance. With the increase of phenyl content, the rigidity of the molecule increases, the radiation resistance and the flame resistance increase, but the cold resistance decreases. Copolymerization, the raw rubber is obtained by destroying the catalyst and removing low boilers in a vacuum, and mixing with silica and organic peroxide structure control agent on a rubber mixing machine to obtain a mixed rubber.

2. Use

It is processed into various products by molding and extrusion, and is used as sealing rings, gaskets, pipes and bars for low temperature resistance, radiation resistance, high damping and ablation resistance in electronic appliances, aviation, aerospace, military and other departments.