Dispersion polymerization of acrylamide with living character and controlled morphologies initiated and mediated by cobalt porphyrin

Abstract

Dispersion polymerization of acrylamide (AM) catalyzed by cobalt porphyrin [cobalt tetramethoxyphenylporphyrin, (TMOP)Co(II)] with the feature of living radical polymerization (LRP) in alcohol/water or dimethylformamide (DMF)/water is described. Well-defined polyacrylamide (PAM) uniform spherical particles with predetermined molecular weight and narrow polydispersity (M_w/M_n = 1.09–1.35) were obtained under mild thermal conditions. Linear first-order kinetics with different feeding ratios of AM and cobalt porphyrin were obtained and the number-average molecular weight (M_n) increased linearly with monomer conversion. However, little research has been reported on (TMOP)Co(II) mediating a living radical dispersion polymerization of acrylamide. The effects of the feeding ratio of monomer and cobalt porphyrin, the solvent, the time of polymerization as well as monomer concentration on the morphology of the spherical particles were investigated. There were increasing trends in the particle size with the increasing concentration of monomer, the time of polymerization and feeding ratio of AM and cobalt porphyrin. The effects of the volume ratio of alcohol or DMF and water were also studied.