Radical Copolymerization of Thionoglycolide and Derivatives for Preparation of Degradable Vinyl Polymers

This study explores the copolymerization behavior of thionated glycolide derivatives with a focus on thionoglycolide (TGD). It was found that TGD exhibits a nuanced reactivity profile, showing the highest compatibility with styrene and tert-butyl acrylate (tBA). Kinetic analysis of the TGD/tBA system conducted at 100 °C in bulk demonstrated comparable incorporation rates for both monomers. Furthermore, RAFT copolymerization mediated by a trithiocarbonate RAFT agent resulted in a well-defined copolymer with Mn = 13.4 kg mol–1 and Đ = 1.2. 2D-NMR microstructural analysis revealed that TGD was exclusively incorporated in its ring-closed S,O-thioketal form, suggesting a selective 1,2-vinyl propagation mechanism. The degradability of the resulting copolymers was also investigated, with NaOCl, NaOMe, and benzoyl peroxide effectively cleaving S,O-thioketal linkages.