The chemical composition of medical silica gel is polydimethylsiloxane, which is a special one in the customization of silica gel products. It is a repeating Si-O bond as the main chain, and the group is directly bonded to the silicon atom through the Si-C bond. Synthetic polymer, the molecular formula is CH3 2SiOn, its physical properties are liquid, jelly or solid according to the number of monomers, ie the number of "n" and the degree of crosslinking, medical polydimethylsiloxane Oxygen is colorless, transparent, odorless, tasteless, hydrophobic, insoluble in water and common organic solvents, and has excellent physical and chemical stability. The main products are silicone oil, silicone gel and silicone rubber.

The silicone oil is mainly composed of a single chain of PDMS, and there is no cross-linking between the chains. The number of monomers varies from a few to several thousand, and the greater the amount, the greater the viscosity of the silicone oil. The silicone gel is a network structure in which a PDMS single chain is cross-linked by a vinyl bond bridge and a long chain is intertwined. The uncrosslinked low molecular weight silicone oil is filled between the network structures, and the silicone oil can be precipitated from the network structure during storage, and no form of SiO2 is added to the silicon gel. Other silicone miscellaneous pieces are also cross-linked by PDMS in a single chain like silicone gel, but they are more cross-linked and contain almost no silicone oil in their mesh structure, due to the additional addition of 30% of the total weight. The non-crystalline structure of SiO2 particles gives the silicone rubber a high mechanical strength. The medical silicone products have very stable physical and chemical properties, corrosion resistance, oxidation resistance, and can be used in the temperature range of -60 ° C and 200 ° C to maintain their properties without any change.