Dispersion polymerization of acrylamide in aqueous solution of ammonium sulfate: Synthesis and characterization

Dispersion polymerization of acrylamide (PAM) has been successfully carried out in aqueous ammonium sulfate media by using poly(acryloyloxyethyl trimethylammonium chloride) (PAOTAC) as the polymeric stabilizer and 2,2'-azobis(2-methyl propionamidine) dihydrochloride (AIBA) as the initiator. The polymerization behaviors with varying concentrations of acrylamide, PAOTAC, AIBA, and ammonium sulfate were investigated. The reaction conditions for stable dispersion were concentrations of 5-10% for acrylamide, 0.6-1.8% for the stabilizer, 0.92-1.84 x 10(-4) mol/L for the initiator, and 24-30% for the salt. The resulting conversion-time curves were S-shaped, as is typically observed in polymerization. Polydisperse spherical particles were formed in the system. An image analyzer photographed the size of the dispersed particles and their distribution was measured. The mechanism and kinetics for the dispersion polymerization were discussed. (C) 2002 John Wiley & Sons, Inc.