“Living” free radical ring-opening copolymerization of 4,7-dimethyl-2-methylene-1,3-dioxepane and conventional vinyl monomers

It is the first report on the atom transfer radical ring-opening copolymerizations of unsaturated cyclic acetal: 4,7-dimethyl-2-methylene-1,3-dioxepane (DMMDO) with conventional vinyl monomers, styrene (St), acrylonitrile (AN) and methyl acrylate (MA) in the presence of ethyl α-bromobutyrate as initiator and CuBr/2,2^′-bipyridyl as catalyst/ligand at 110 °C. ¹H, ¹³C NMR and IR data show that the copolymerizations of DMMDO with St (or AN or MA) yield the copolymers, poly(DMMDO-co-St) [or poly(DMMDO-co-AN) or poly(DMMDO-co-MA)] with narrow molecular weight distribution, and low content of DMMDO in the copolymers for electron-donor St, higher contents of DMMDO for electron-acceptor AN or MA are observed.