PREPARATION AND CHARACTERIZATION OF HYDROGELS OBTAINED BY GRAFTING OF ACRYLONITRILE ONTO CASSAVA STARCH BY CERIC ION INITIATION

Graft starch-polyacrylonitrile copolymers have been obtained from cassava starch (yucca starch or tapioca), which was pre-heated at 65 and 95-degrees-C for different lengths of time. The copolymerization was carried out by using ceric ion as initiator at different concentrations (2.0 to 8.0 mmol/L) and also varying both the length of time of copolymerization and the ratio of monomer to starch. The composition, or grafting parameters, of all the obtained copolymers was determined by weight difference after they were extracted with dimethylformamide and hydrolyzed with an acidic solution. Samples of these copolymers were also hydrolyzed with an aqueous solution of potasium bydroxide to produce the corresponding hydrogels, and its absorbency in water was determined.