nce of a dehydrofluorination initiator for the fluoroelastomer and from a polyorganosiloxane having reactive functionality and the formula: ##STR5## where R is an alkyl, alkenyl or aryl group having less than 19 carbon atoms or an aryl group substituted with an alkyl or alkenyl group having less than 19 carbon atoms, the functional group A is hydrogen, hydroxy, alkoxy, amino, epoxy, vinyl, acrylic