Dimethyl silicone rubber is referred to as methyl silicone rubber:
The preparation of high molecular weight linear dimethyl polysiloxane rubber requires high-purity raw materials. In order to ensure the purity of the raw materials, the industry is usually first to purify the dimethyl dimethyl polysiloxane with a content of more than 99.5%. Chlorosilane is hydrolyzed and condensed in an ethanol-water medium under acid catalysis, and a bifunctional siloxane tetramer, namely octamethylcyclotetrasiloxane, is separated, and then the tetracyclic body is subjected to the action of a catalyst. , forming a polymer linear dimethylpolysiloxane.
Dimethyl silicone rubber is a colorless and transparent elastomer, which is usually vulcanized with organic peroxides with high activity. Vulcanized rubber can
When used in the range of -60~+250℃, the vulcanization activity of dimethyl silicone rubber is low, and the permanent deformation of high temperature compression is large, so it is not suitable for thick products. Since methyl vinyl silicone rubber containing a small amount of vinyl has better properties, dimethyl silicone rubber has been gradually replaced by methyl vinyl silicone rubber. Other types of silicone rubbers produced and used today, in addition to containing dimethylsiloxane structural units, also contain more or less other bifunctional siloxane structural units, but their preparation methods are different from those of dimethylsiloxane. There is no essential difference in the preparation method of rubber. The preparation method is generally to hydrolyze and condense a desired difunctional silicon monomer under the conditions conducive to the formation of the ring body, and then add octamethacrylate in the required proportion. base cyclotetrasiloxane, and then co-reacted under the action of a catalyst.