RAFT/MADIX Copolymerization of Vinyl Acetate and 5,6-Benzo-2-methylene-1,3-dioxepane

The synthesis of well-defined degradable poly(vinyl acetate) analogues is achieved by RAFT copolymerization of 5,6-benzo-2-methylene-1,3-dioxepane (BMDO) and vinyl acetate (VAc) using methyl (ethoxycarbonothioyl)sulfanyl acetate (MEA) as controlling agent. Several monomer mixtures with low BMDO contents (<30 mol %) are employed to prepare different copolymers. In all the cases, the evolution of molar masses and the dispersity values (<1.26) confirm the controlled feature of the polymerization. The livingness of the obtained chains is demonstrated by successful chain extension experiments with VAc, although the presence of dead chains is also shown. The introduction of ester groups into the main chain of these P(VAc-co-BMDO) copolymers allows their degradation when treated with a mixture of KOH/MeOH in reflux during 2.5 h.