Graft copolymerization of chitosan with acrylic acid under microwave irradiation and its water absorbency

Acrylic acid was grafted onto chitosan by using the ceric ion as an initiator in the presence of N,N′-methylenebisacrylamide (MBA) as a crosslinker under microwave irradiation based on our modified apparatus. The effects of some grafting variables on the water absorbency were investigated by orthogonal tests, and the optimal conditions were described. The structure of the graft copolymer was confirmed by IR spectrum and TGA. The influence of microwave power and the amounts of the initiator and crosslinker on the reaction were further studied. The result shows that the microwave irradiation method can increase the reaction rate by eight times over the conventional method. The graft copolymer is an effective superabsorbent resin (SAR) and can absorb water 704 times its own dry weight.