Synthesis of poly(vinyl pyrrolidon-co-acrylamide) flocculants by radical polymerization

The copolymerization of acrylamide (AAm) and 1-vinyl-2-pyrrolidon (VP) using disodium salt of 4,4′-azo-bis(4-cyanopentanoic acid) (ACPA-Na) as water-soluble catalyst was carried out to yield poly(acrylamide-co-1-vinyl-2- pyrrolidon) in aqueous solution at 70°C. The cross-linking of the polymer formation of water-insoluble polymer could be avoided by the addition of K ₂CO₃ to raise the pH of the reaction mixture above 7.0. The copolymers were used as flocculants in the flocculation of suspension of lineal concentrate and showed good flocculating properties.