The mechanical properties of silicone elastomers at room temperature
are inferior to those of other elastomers.Silicone elastomers are unaffected by oxygen and ozone on natural ageing.
Because of their water-repellency, silicone elastomers are not seriously affected
by aqueous solutions of most chemical reagents.They are attacked by
strong acids and alkalis. General purpose elastomers are swollen by aliphatic,
aromatic and chlorinated hydrocarbons but much improved resistance is
shown by nitrile- and fluorine-containing silicones. In general, room temperature-
cured materials have lower solvent resistance.
The major use of conventional silicone elastomers is in aircraft components
where high and low temperature properties and electrical insulation
characteristics are utilized, e.g. gaskets, sealing strips, ducting and cable
insulation. Room-temperature vulcanizing silicone elastomers are used for
the encapsulation of electronic and electrical equipment and for caulking.
Liquid silicone elastomers are used for injection moulding of such components
as seals, diaphragms and O-rings. They are ideal for moulding intricate
shapes and are particularly suited to high-speed, high-volume operations.
