A novel vulcanization system for curing silicone rubber by Diels-Alder reaction has been suggested. Some cyclopentadienyl silanes or siloxanes such as were used as efficient crosslinking agent for vulcanization of polysiloxanes having vinyl groups. Compounds III IV could also be used as hardening agents though each had only one cyclopentadienyl group. It might

probably be that the alkoxysilanes first reacted with the silanols on the surface of the filler (SiOs) to form polycyclopentadienyl compounds the latters then crosslinked with the vinyl groups leading to vulcanization of polysilo-xanes. The resulting elastomers possessed higher tensile strength

tear strength and elongation Attempts to cure silicome rubber with compounds.