Preparation of DEAE cotton-g-poly(methacrylic acid) for use as ion exchanger

Abstract

Diethylaminoethyl (DEAE) cottons having different % N were prepared by reacting cotton cellulose in the fabric form with diethylamine hydrochloride at different concentrations in the presence of sodium hydroxide. The modified samples so obtained were subjected to the graft polymerization reaction using methacrylic acid (MAA) as the vinyl monomer and potassium permanganate-citric acid system as the initiator. The percentage of grafting (PG) was found to increase by increasing the % N, indicating that the presence of the DEAE groups in the molecular structure of the cellulose enhances the susceptibility of the latter to grafting. DEAE groups seem to act as additional sites for grafting; and/or, by virtue of their basicity, they interact with the citric acid, thereby creating primary free radicals in the vicinity of the cellulose. As a result, grafting increases, increasing the initiator and monomer concentration, as well as the polymerization time and temperature functions in favor of the PG. It was also disclosed that DEAE cotton-g-poly (methacrylic acid) serves as cationic and anionic ion exchanger by virtue of the presence of both DEAE and carboxylic groups. This was evidenced by the results of a detailed investigation on the ability of the exchanger to adsorb direct and basic dyes as well as Cu2+ ions. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 67: 739–745, 1998