Solvent effects on polymerization of functionalized monomers in presence of alkyl halide/CuBr without a ligand

A modified system of atom transfer radical polymerization was used to perform polymerization of sodium o-methacryloylaminophenylarsonate (o-MAPHA-Na). The reaction was carried out without ligand at 48 °C for 45 h with methyl 2-chloro-propionate (MCP) as the initiator, copper bromide (CuBr) as the metal, and different mixtures of polar solvents, including: dimethylformamide (DMF):H₂O (60:40), dimethylsulfoxide (DMSO):H₂O (20:80), and DMSO. The ¹H NMR spectra showed that MCP was covalently attached as end group of the resulting polymers. Unexpectedly, we found that o- and p-MAPHA-Na could polymerize in the presence of alkyl halides without any initiation method to produce free radicals from alkyl halide. Further experiments suggested that radicals could be generated from the used monomer by initiation methods such ultraviolet radiation of environmental light or temperature. Thus, it was possible that the monomer generated phenyl radicals by breaking its C-As bond. Reactions of o-MAPHA-Na and o-MAPHA with MCP and different ratios of H₂O:DMF and H₂O:Metanol (MeOH) showed that water was necessary for polymerization to proceed. Finally, we found that o-MAPHA underwent self-initiated polymerization when water was present in the reaction media.