Vinylidene Chloride Copolymerization with Methyl Acrylate by Degenerative Chain Transfer

摘要

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_2H_5) and 1-phenylethyl iodide. The higher apparent chain transfer constant was found for the dithioester with R= CH(CH_3)C(O)OC_2H_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 Predici~R 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.