Dithioketal Polymers Via Radical Polymerization of γ-Dithiobutyrolactone

Polymers bearing in-chain dithioketal groups are an emerging class of materials with specific properties like reactive oxygen species (ROS)-responsiveness and vitrimer-type behavior. Until now, these polymers have been exclusively produced by step-growth polymerization or polyaddition; herein, we report the first chain polymerization leading to dithioketal polymers. γ-dithiobutyrolactone (DTBL) is radically copolymerized with a series of conjugated monomers to yield copolymers with ring-retained dithioketal units exclusively. DFT calculations rationalize the contrasting behaviors of DTBL and its thionolactone analogue γ-thionobutyrolactone (TBL), highlighting how electronic effects of the ring heteroatoms govern propagation efficiency and ring-retention versus ring-opening pathways. The ability of DTBL to bring degradability to thermosets, latexes, and RAFT-derived complex architectures is revealed.