where ≡ represents two methyl groups and the rest of the
polymer chain.
This reaction has been used for high-consistency silicone
rubbers (HCRs) such as those used in extrusion or injection
molding, as well as those that are cross-linked at elevated
temperatures. The peroxide is added before processing. During
cure, some precautions are needed to avoid the formation of
voids by the peroxide’s volatile residues. Postcure may also
be necessary to remove these volatiles, which can catalyze
depolymerization at high temperatures.