Kinetics of the SET-LRP of Oligo(ethylene glycol) Methacrylate Initiated with Chitosan Based Macroinitiator

Chitosan O-poly(oligo(ethylene glycol) methacrylate) (CS-O POEGMA) was synthesized through single electron transfer living radical polymerization (SET-LRP) of OEGMA, using O brominated chitosan (CS-Br) as an initiator and Cu (I)Br as the catalyst. The polymerization kinetics under different conditions was studied using in situ 1H NMR. Results showed that with the decreasing of medium pH, the polymerization rate declined. When CS-Br concentration was raised to a certain extent, gelation took place during polymerization. The degree of substitution of bromobutyrate groups in CS-Br had little effect on the polymerization kinetics in pH 5.0 buffer solution, suggesting the conformation of chitosan backbone was in an extended state and the controllability of the polymerization was the best.