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 degreesC; pre-formation of an aldehyde-amine adduct, which is subsequently dropped into an inverse emulsion of starch-graft-polyacrylamide. The reaction temperature was 45 degreesC, the reaction time was 3-4 h, and the pH was 5.5.