Preparation and characterization of interpenetrating network beads of poly(vinyl alcohol)-grafted-poly (acrylamide) with sodium alginate and their controlled release characteristics for cypermethrin pesticide

Interpenetrating network polymeric beads of poly(vinyl alcohol)-grafted-acrylamide with sodium alginate have been prepared by crosslinking with glutaraldehyde. Cypermethrin, a widely used pesticide, was loaded with 80% efficiency in these hydrogel beads. The beads were characterized by Fourier transform infrared spectroscopy to confirm the grafting. Scanning electron microscopy was used to know the morphology of the beads. Equilibrium swelling experiments indicated that swelling of the beads decreased with an increase in crosslinking. The in vitro release studies were performed under static conditions and the release data have been fitted to an empirical relation to estimate the transport parameters, The diffusion coefficients have been calculated for the transport of pesticide through the polymeric beads using the initial time approximation method. These values showed decrease with increasing crosslinking as well as increasing pesticide loading. (C) 2002 John Wiley Sons, Inc.