Vinylidene Chloride Copolymerization with Methyl Acrylate by Degenerative Chain Transfer

Degenerative chain transfer copolymerization of vinylidene chloride (VC 2 ) with methyl acrylate (MA) was investigated at 70°C in benzene. Different dithiocompounds ZC(S)SR were tested as chain transfer agents in the RAFT process (Reversible Addition-Fragmentation Chain Transfer) while 1-phenylethyl iodide was tested as chain transfer agent in the ITP process (Iodine Transfer Polymerization). Dithioesters (Z= Ph) proved to be much more efficient to control VC 2 /MA copolymerization than both the xanthate (Z= OC 2 H 5 ) and 1-phenylethyl iodide. The higher apparent chain transfer constant was found for the dithioester with R=CH(CH 3 )C(O)OC 2 H 5 . Dithioesters had a pronounced effect on the kinetics, R=C(CH 3 ) 3 leading to the most important retardation effect. As illustrated by using the Predict® simulation package, the transfer to VC 2 was thought to be responsible for the limitation of the attainable molecular weight in a living fashion. In spite of this side reaction, chain extension as well as a block copolymerization with styrene were successfully performed.