Synthesis and characterization of amphoteric polyacrylamide by dispersion polymerization in aqueous salts solution

Abstract

Amphoteric terpolymers composed of acrylamide, 2-methylacryloylxyethyl trimethyl ammonium chloride, and 2-acrylamido-2-methyl-1-propane sulfonate were prepared via free-radical polymerization in aqueous solution of ammonium sulfate (AS), using poly(2-methylacryloylxyethyl trimethyl ammonium chloride) as stabilizer to yield terpolymers with random distributions. The particle size of the synthesized amphoteric polyacrylamide (AmPAM) ranged from 1 to 8 μm and the intrinsic viscosity ranged from 5.6 to 14.2 dL/g. The influences of aqueous solution of AS concentration, stabilizer concentration, initiator concentration, monomer concentration on the conversion of monomer, the intrinsic viscosity, and the particle size were systematically investigated. The characteristic of amphoteric polymer was also be studied. Throughout the study, we found that the isoelectric point of the amphoteric polyelectrolyte we synthesized is about 7. With the increase in sodium chloride, the reduced viscosity of AmPAM increased. Among the different type of inorganic salt, the degree of influence of anionic is I > Br > Cl.