Polymerization of acrylamide in a micellar medium: Inhibition effect of surfactants



The polymerization of acrylamide (AM) in an aqueous medium and in the presence of anionic [sodium lauryl sulfates (NaLS)], cationic [cetyltrimethyl ammonium bromide (CTAB)], and nonionic (Brij-35) surfactants was carried out at 60°C with potassium persulfate as the initiator. The percentage conversion and rate of polymerization (Rp) decreased in the presence of the surfactant, and the inhibition effect of the surfactant was in the order CTAB > Brij-35 > NaLS. The viscosity data, namely, the intrinsic viscosity, viscosity-average molecular weight, and shape factor, were also obtained in each case. The polymer was characterized by Fourier transform infrared spectroscopy and thermogravimetric analysis. The inhibition effect of the surfactant on Rp of AM was explainable on the basis of hydrophobic and electrostatic interactions during the association/binding between the surfactant and monomeric free radical of the monomer. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011