Synthesis of Graft Copolymers by Combination of PET-RAFT and Ring Opening Polymerization at Ambient Temperature

Abstract

Well-defined poly(methyl acrylate-co-hydroxyethyl acrylate)-graft-poly(epsilon-caprolactone) (PMA-g-PCL) copolymers were successfully synthesized via a combination of photoinduced electron/energy transfer-reversible addition-fragmentation chain transfer (PET-RAFT) and ring-opening polymerization (ROP) under ambient conditions. Initially, random copolymers of methyl acrylate (MA) and 2-hydroxyethyl acrylate were prepared through PET-RAFT polymerization. These copolymers, bearing pendant hydroxyl moieties, subsequently served as macroinitiators for the grafting of poly(epsilon-caprolactone) side chains via ROP. The influence of monomer concentration in feed and polymerization time on grafting density and efficiency was investigated. Structural and molecular characterization of both the precursor copolymers and the final graft copolymers was conducted by 1H-NMR, FT-IR, and GPC analysis. The combined spectroscopic and chromatographic results confirmed that both PET-RAFT and ROP proceeded in a controlled manner, resulting in graft copolymers with well-defined architectures and narrow molecular weight distributions.