Conventional and RAFT copolymerization of tetrafluoroethylene with isobutyl vinyl ether

Abstract

The solution copolymerizations of tetrafluoroethylene (TFE) with isobutyl vinyl ether (iBuVE), using both conventional radical and RAFT/MADIX methods, are presented. O-Ethyl-S-(1-methyloxycarbonyl)ethyl xanthate and benzoyl peroxide (BPO) were used as RAFT chain transfer agent and initiator, respectively, in dimethyl carbonate. Degrees of polymerization ca. 20 were targeted. In all cases, alternating copolymers were obtained. Poly(TFE-alt-iBuVE) copolymers synthesized via conventional radical copolymerization using from 1 to 30 mol % BPO exhibited molar masses varying between 11000 and 4400 g mol–1, respectively, and broad dispersities (Đ = 2). Poly(TFE-alt-iBuVE) copolymers synthesized by RAFT/MADIX had molar masses ranging from 1200 to 2000 g mol–1 at 15 min to 24 h, respectively, and more narrow Đ (1.08 and 1.11, respectively). The ratio of chain ends is nearly time invariant, with a slight tendency to accumulate TFE chain ends over time. Proton transfer from the solvent to the macroradicals was observed in both the conventional and RAFT polymerizations. This work is the first study of the RAFT/MADIX solution copolymerization of TFE with a vinyl ether.