Acid-assisted depolymerization of RAFT-derived PMMA.

Chemical recycling of vinyl polymers to their constituent monomers offers a route to closed-loop reuse, but depolymerization of polymethacrylates typically requires very high temperatures or catalysts. Here, we show that simple Brønsted acids accelerate the depolymerization of RAFT-derived poly(methyl methacrylate). Addition of p-toluenesulfonic acid increased depolymerization by more than nine-fold within the first hour and by nearly an order of magnitude at longer reaction times relative to thermal depolymerization alone, and this acceleration compounded additively with green-light irradiation. The magnitude and duration of acceleration depended on the identity of the Brønsted acid, suggesting a role for the conjugate base beyond simple proton donation. These results suggest acid addition as a strategy for accelerating depolymerization of RAFT-derived polymers that is compatible with existing thermal and photochemical methods.