Unexpected reactivity for the raft copolymerization of oligo(ethylene glycol) methacrylates

Homo- and copolymers of di(ethylene glycol) methyl ether methacrylate (DEGMA) and oligo(ethyleneglycol) methyl ether methacrylate (OEGMA 1100) were synthesized with various chain lengths via reversible addition fragmentation chain transfer (RAFT) polymerization in ethanol using [MMRAFT] ratios of 100 and 200. Kinetic investigations on the homo- and copolymerization of these monomers were performed using a parallel synthesizer resulting in well-defined polymers with poly- dispersity indices mostly below 1.3. The polymerization kinetics are presented and discussed in detail surprisingly revealing that the DEGMA homopolymerization is slower than the OEGMA1100 homopolymerization. Transfer coefficients c trarp were estimated to be ~0.5 for the RAFT polymerization of both DEGMA and OEGMA1100 resulting in hybrid behavior at the beginning of the polymerizations. Subsequent copolymerization also revealed fast incorporation of the OEGMA1100 and relatively slow incorporation of DEGMA resulting in well-defined copolymers with a molecular weight up to 100 kDa and polydispersities around 1.20. © 2009 Wiley Periodicals, Inc..