Inverse Emulsion of Starch‐graft‐Polyacrylamide

An inverse emulsion of cationic starch‐graft‐polyacrylamide was prepared by inverse emulsion polymerization and a subsequent Mannich reaction. The copolymerization was carried out using potassium persulfate as initiator. The reaction conditions and factors affecting emulsion stability were studied. Experiments showed that a high solids content, a high cationic degree and a stable latex can be obtained under the following condition: A molar ratio starch/acrylamide/formaldehyde/dimethylamine of 0.11:1:1:1.2; a stable inverse emulsion system; graft copolymerization of starch and acrylamide for 2‐3 h at 50 °C; pre‐formation of an aldehyde‐amine adduct, which is subsequently dropped into an inverse emulsion of starch‐graft‐polyacrylamide. The reaction temperature was 45 °C, the reaction time was 3‐4 h, and the pH was 5.5.