Copper‐Based Reversible Deactivation Radical Polymerization of Isopropenyl Boronate and Depolymerization of the Bromine‐Terminated Polymer

In this work, we investigated the depolymerization behavior of bromine-terminated poly(isopropenylboronic acid pinacol ester) [poly(IPBpin)] by copper catalyst in comparison with poly(methyl methacrylate) (PMMA), whose depolymerization behaviors have been extensively studied. Halogen-terminated poly(IPBpin)s were precisely synthesized via copper-mediated reversible deactivation radical polymerization with a bromide initiator. In the presence of a copper catalyst, the IPBpin polymers underwent depolymerization to regenerate the monomer (i.e., IPBpin) at temperatures below 100°C, in contrast to the inert behavior of bromine-terminated PMMA under the same conditions. The ceiling temperature was determined to be 76°C (1.0 M), which was much lower than that of PMMA (202°C, 1.0 M). Notably, despite exhibiting superior depolymerizability to PMMA, the IPBpin polymers showed comparable or even higher thermal stability.