Silicones:-
They are a group of organosilicon polymers, which have (R2SiO) as a repeating unit. Preparation of Silicones. The starting materials for the manufacture of silicones are alkyl or aryl substituted silicon chlorides RnSiCl4n, where R is alkyl or aryl group.
When methyl chloride reacts with silicon in the presence of copper as a catalyst at a temperature 570 K, various types of methyl substituted chlorosilanes are formed. Hydrolysis of dimethyl dichloro silane i.e., (CH3)2SiCl2 followed by condensation polymerisation forms straight chain polymer i. e., silicone.
