Preparation of Potato Starch-graft-acrylic Acid Superabsorbent Resin

Acrylic acid(AA)was grafted onto fully gelatinized potato starch for synthesizing potato starchgraft-acrylic acid superabsorbent by using redox synergistic agent(CJ-1).The optimum conditions for obtaining maximum water absorbency were as follows:the contents of initiator and cross-linking agent were 0.75%and 0.25%,respectively,based on the amount of monomer;the neutralization degree of acrylic acid was 85%;the mass ratio of potato starch to acrylic acid was 1∶4.5(g/g);The temperature of grafting and cross-linking were 60℃and 120℃,respectively;the cross-linking time was 3.0h.The sample exhibited water absorbency of 691.60g/g in distilled water and 54.80g/g in 5wt% NaCl solution,respectively.It was showed from the thermal analysis that the absorbent resin had a good heat resistance and water existed mainly in the form of free water besides a certain amount of bound water and irreducible water. SEM images indicated that the potato starch graft copolymerized completely and the microstructure of the resin was porous with deep wrinkles,which was beneficial to absorb or discharge water in all directions.