Abstract: Canna edulis Ker starch-acrylic acid graft copolymer was prepared by an inverse microemulsion method using ammonium persulfate as the initiator and N, N＇-meyhylene-bisacrylamide as cross-linking agent under nitrogen protection. An inverse emulsion system containing Canna edulis Ker starch was formed under an oil-to-water ratio of 1.2:1, complex emulsifier amount of 30%, and emulsifier HLB (hydrophilic-lipophilic balance) of 7.36. The optimal copolymerization conditions of Canna edulis Ker starch and acrylic acid were acrylic acid amount of 16 mL, initiator amount of 3.5%, cross-linking agent amount of 0.8%, and neutralization degree of acrylic acid of 70%. The water-absorbing capacity of graft copolymers prepared under the optimal conditions was 1340 g/g. Meanwhile, infrared spectral analysis revealed that acrylic acid was successfully grafted onto Canna edulis Ker starch.

Key words: inverse microemulsion, canna starch, graft polymerization, copolymer