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The preparation of carboxymethyl (CM)-Cassia tora gum (CTG) with monochloroacetic acid and sodium hydroxide was investigated under different reaction conditions. The carboxymethylation reaction was studied with respect to the degree of substitution of CM-CTG. The variables studied were the concentration of reactants, methanol-water ratio (solvent), reaction time, and reaction temperature. Carboxymethylation of CTG increased its solubil-ity in cold water and the stability of its paste to microorganisms. Regardless of the degree of substitution of these products, their aqueous solutions were characterized by non-Newtonian pseudoplastic behavior. Determination of the rheological properties of CM-CTGThe rheological properties were determined with a Brookfield digital viscometer (model RVTD, Stough-Correspondence to: V. Kumar (vineetkmadan@yahoo.co.in) or P. L. Soni (sonipl@icfre.org).

Graft copolymerization of acrylamide onto Cassia tora gum was studied in an aqueous medium using ceric ammonium nitrate-nitric acid as the redox initiator. To optimize the reaction conditions for obtaining maximum percent grafting, the concentrations of Cassia tora gum, ceric ammonium nitrate, acrylamide, and nitric acid, time, and temperature were varied. Results are discussed and a reaction mechanism is proposed.

The graft copolymerization of acrylonitrile (AN) onto Cassia tora gum (CTG) was carried out in an aqueous medium with a ceric ammonium nitrate (CAN)nitric acid initiation system. The percentage grafting and percentage grafting efficiency were determined as functions of the concentrations of CAN, nitric acid, AN, and CTG and the polymerization temperature and time. The results are discussed, and a reaction mechanism is proposed.

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