Synthesis of Methacrylate‐Terminated Block Copolymers with Reduced Transesterification by Controlled Ring‐Opening Polymerization

This work presents a robust method to achieve the synthesis of low molecular weight polyesters via ring‐opening polymerization (ROP) initiated by 2‐hydroxyethyl‐methacrylate (HEMA) when using triazabicyclodecene (TBD) as catalyst. The effect that the HEMA:TBD ratio has upon the final reaction rate and final polymer molecular architecture is discussed. The optimum HEMA:TBD ratio and reaction conditions required to minimize competing transesterification reactions are determined, in order to synthesize successfully the target ROP macromonomer species containing only a single 2‐methacryloyloxyethyl end‐group. Additionally, to confirm the terminal end‐group fidelity of the product macromonomers and confirm TBD utility for block copolymer manufacture, a small series of di‐block polyesters are synthesized using TBD and shown to exhibit good control over the final polymer structure whilst negating the side transesterification reactions, irrespective of the monomers used. Methacrylated block co‐polyesters are synthesized via triazabicyclodecene (TBD) catalyzed ring‐opening polymerization (ROP). TBD has been successfully employed as an active and selective catalyst for HEMA‐initiated ROP of D,L‐lactide (LA), trimethylene carbonate (TMC), and ε‐caprolactone (CL) in order to synthesize, under mild and standard laboratory conditions, homopolymers, and block copolymers with controlled molecular weight, low polydispersity, and a mono‐methacrylate final architecture.