Anionic polyacrylamide “water-in-water” emulsion prepared by dispersion polymerization in mixed salt aqueous media

Abstract Polyacrylamide “water-in-water” emulsion was regarded as a new generation of water-soluble polymeric materials and has attracted much attention from both academia and industry because of its environmentally-friendly character. Anionic polymeric “water-in-water” emulsions prepared by dispersion polymerization of acrylamide (AM) and sodium acrylic acid (NaAA) in mixed solution of Na2SO4 and (NH4)2SO4 are reported in this paper, and the parameters influencing polymerization and the final dispersion stability, including, N2 flow rate, chain transfer agent content, inorganic salt content, and the molar ratio of AM to NaAA were examined and opitimized. It was found that the intrinsic viscosity of resulting copolymers decreased as the N2 flow rate and CTA concentration increased, and the resultant dispersions with 27 % ∼ 28 % inorganic salt have regular particle shape, lowest particle size, better flowability and storage stability. The salt level in the reaction system would also dominate the time that the dispersion formed, and the ratio of AM to NaAA would influence the total monomers conversion and polymerization rate.