Radical Group-Transfer Polymerization of 2-Thiocyanatoethyl Vinyl Ether

2-Thiocyanatoethyl vinyl ether (TCEVE), a vinyl ether, was observed to be polymerized in moderate yields with radical initiators such as dimethyl 2,2‘-azobisisobutyrate (MAIB) and 2,2‘-azobisisobutyronitrile. The rate ( R p ) of polymerization of TCEVE with MAIB in benzene at 60 °C was given by R p = k [MAIB] 0.8 [TCEVE] 1.0 . The overall activation energy of the polymerization was 105 kJ/mol. The number-average molecular weight ( M̄ n ) of the resulting poly(TCEVE) was in the range of 1700−3600, corresponding to polymerization degrees of 13−27. M̄ n tended to decrease with increasing TCEVE concentration, suggesting chain transfer to the monomer. The IR, 1 H-, and 13 C-NMR spectra and the thermal degradation behavior of the radically formed poly(TCEVE) distinguishably differed from those of a cationically formed polymer and indicated that the radical polymerization of TCEVE propagates with transfer of the cyano group. Radical copolymerizations of TCEVE with some vinyl monomers were examined on the monomer reactivity ratios and structures of copolymers.