The successful impossible radical ring-opening copolymerization of thionolactones and methacrylates via an auxiliary third comonomer

Polymethacrylate derivatives are widely used in various industrial applications. The incorporation of degradable thioester bonds in polymethacrylates to achieve degradability/recyclability upon disposal is a challenge. Unfortunately, the most efficient thionolactone to insert cleavable thioester linkages does not copolymerize with methacrylates. We show that a small amount of the thionolactone can be inserted into polymethacrylates by the use of methyl acrylate or N-phenyl maleimide as an auxiliary third comonomer. We confirmed the selective degradation of the copolymer via aminolysis. The intriguing incorporation of the thionolactone via the formation of triads is demonstrated using Monte Carlo simulations and such method is also used to optimize the synthesis conditions. Copolymers of 60,000 g.mol-1 is obtained that could be degraded with a 25-fold reduction of size, confirming the model-based insights and opening the pathway to degradability for polymethacrylates. This approach is also successfully extended to poly(butyl methacrylate), and water-soluble poly(oligo(ethyleneglycol) methacrylate) for biomedical applications. Polymethacrylate derivatives are widely used in industry but precise incorporation of degradable thioester bonds in polymethacrylates to achieve degradability remains challenging. Here the authors show that a thionolactone can be inserted into poly(methyl methacrylate) using an auxiliary third comonomer.