Atom Transfer Radical Polymerization of Methyl Methacrylate Utilizing an Automated Synthesizer

The homogeneous atom transfer radical polymerization of methyl methacrylate mediated by CuBr/N-(n-hexyl)-2-pyridylmethanimine was successfully carried out using an automated synthesizer. The effects of initiators, solvents and reactant ratios on the polymerization were investigated. Three different kinds of initiators, namely ethyl 2-bromoisobutyrate, (1-bromoethyl)-benzene, and p-toluenesulfonyl chloride, were utilized to initiate the polymerization and ethyl 2-bromoisobutyrate was proven to be the best initiator for the studied system in terms of molecular weight control and narrow polydispersities of the obtained polymers. The solvents used (i.e., toluene, p-xylene, and n-butylbenzene) were found to have strong effects on the polymerization. The reactions in toluene and p-xylene were well-controlled and almost the same polymerization rates were observed. However, the reaction rate dramatically increased in the case of n-butylbenzene, resulting in radical termination during the polymerization. The initiator and Cu(I) concentrations had a positive effect on the polymerization rate. In the meantime, all the reactions were controlled and polymers with predetermined molecular weights and low polydispersity indices (< 1.3) were obtained.