Silicone graft copolymers with acrylonitrile, chloroprene, styrene, methyl methacrylate, and an olefin.

Reaction of Me methacrylate, styrene, chloroprene and acrylonitrile monomers with siloxane polymers bearing thiol groups using a free radical initiator have been studied and performed a competing thiol-ene reaction with an olefins. One siloxane has a thiol group attached to each silicon atom, the second has thiol groups linked to about 5% of the silicons, and the third, the α,ω-polymer, has a thiol group at each end. At one extreme of the reaction used conditions - by choosing an olefin, or by using low monomer concn. and high thiol concn. - the olefin or monomers were linked singly to the sulfur by the thiol-ene reaction, and at the other extreme, many became attached to the sulfur atoms when the thiol group behaved as a chain transfer agent, so that graft copolymers formed. The turbidity of cast films and the presence of two glass transitions in the DSC traces are taken as evidence for two phases in the solid states. [on SciFinder(R)]