AbstractThe synthesis of poly[vinylamine-co-(sodium acrylate)] [P(VAm-co-NaAA)] and its application as a paper strength additive have been investigated. P(VAm-co-NaAA) was synthesized by the alkaline hydrolysis of poly[N-vinylformamide-co-(acrylic acid)] (PNVFAA). The influence of polymer concentration, hydrolysis temperature, and NaOH concentrations on the extent of hydrolysis were examined experimentally. The hydrolysis was 100% completed under the following conditions: hydrolysis temperature 80 °C, hydrolysis time 8 h, polymer concentration 2%, and NaOH concentration 0.045 mol/g of PNVFAA. P(VAm-co-NaAA) obtained in this manner increased the tensile strength and folding endurance of paper by 44% and 48%, respectively, and the strength increase was greater than that obtained with the commercially available polyvinylamine.