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

摘要

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.