Swelling dynamics of a macromolecular hydrophilic network and evaluation of its potential for controlled release of agrochemicals

A hydrophilic macromolecular matrix has been prepared by performing graft copolymerization of crosslinked polyacrylamide chains onto carboxymethyl cellulose and polyvinyl alcohol, and water sorption capacity of grafted network was evaluated gravimetrically. The effects of chemical architecture of the gel, pH and temperature of the swelling medium and presence of electrolyte were investigated on water uptake by the grafted hydrogels. In order to evaluate the controlled release potential of the matrix, it was loaded with KNO3 as a model agrochemical and the release kinetics was studied as a function of the chemical composition of the hydrogel. The hydrogels were also characterized by IR spectral analysis and structural parameters such as molecular weight between crosslinks (M-c), crosslink density (q(e)) and number of elastically effective chains were determined. The mechanism of water transport through the synthesized grafts hydrogels was also explored. (C) 2002 Elsevier Science B.V. All rights reserved.