Atom transfer radical polymerization of glycidyl methacrylate:: A functional monomer

A detailed investigation of the polymerization of glycidyl methacrylate (GMA), an epoxy-functional monomer, by atom transfer radical polymerization (ATRP) was performed. Homopolymers were prepared at relatively low temperatures using ethyl 2-bromoisobutyrate (EBrIB) as the initiator and copper halide (CuX) with pentamethyldietbylenetriamine (PMDETA) as the catalyst system. The high polymerization rate in the bulk did not permit polymerization control. However, homopolymerization in solution enabled us to explore the effects of different experimental parameters, such as temperature, solvent (toluene vs. diphenyl ether) and initiator concentration, on the controllability of the ATRP process. SEC analysis of the homopolymers synthesized confirmed the importance of solvent character on molecular weight control, the lowest polydispersity indices (M-w/M-n < 1.25) and the highest efficiencies being found when the polymerizations were performed in diphenyl ether in combination with a mixed halide technique. A novel poly(glycidyl methacrylate)-block-poly (butyl acrylate) (PGMA-b-PBA) diblock copolymer was prepared through ATRP using PGMA-Cl as a macro-initiator. This chain growth experiment demonstrated a good living character under the conditions employed, while simultaneously indicating a facile synthetic route for this type of functional block copolymer. In addition, the isotacticity parameter for the PGMAs obtained was estimated using H-1 NMR analysis which gave a value of sigma(GMA) = 0.26 in agreement with that estimated in conventional radical polymerization. [GRAPHICS] SEC chromatograms of PGMA-Cl macroinitiator and PGMA-b-PBA diblock copolymer.