Dynamics of controlled release of potassium nitrate from a highly swelling binary polymeric blend of alginate and carboxymethyl cellulose

Highly water absorbing and homogeneous binary biopolymeric blends in bead form were prepared of calcium alginate and carboxymethyl cellulose by solution cast method. The prepared blends were evaluated for controlled delivery of KNO3 taking it as a model agrochemical. The beads characterized by Fourier transform infrared spectroscopy (FTIR) and Scanning electron microscopy (SEM) were used to investigate the molecular structure and morphology of beads. The swelling experiments were performed for different compositions of beads and at varying pH and temperature of the aqueous media. The release experiments were performed under static and varying experimental conditions and the release data obtained were conductometrically fitted to Ficks equation to evaluate diffusion coefficients of released KNO3. The release results were further analyzed by Ficks power law equation, and the possible mechanisms of KNO3 release were explored at different experimental conditions. (C) 2007 Wiley Periodicals, Inc.