Controlled release of insecticide carbaryl from crosslinked carboxymethylcellulose beads

Abstract

Copper-carboxymethylcellulose (CuCMC) beads containing carbaryl were prepared by the ionotropic crosslinking of sodium carboxymethylcellulose (NaCMC) with copper ions. The beads were characterized by carbaryl encapsulation efficiency, bead diameter, equilibrium swelling degree and carbaryl release kinetics. The spherical nature and surface morphology of the beads were confirmed by scanning electron microscopy (SEM). The effects of the bead preparation conditions such as percent of NaCMC, carbaryl:sodium carboxymethylcellulose (car:NaCMC) ratio, crosslinker concentration and kaolin addition as a filler on carbaryl release were studied. The release results indicated that carbaryl. release from the beads increases with increase in the percentage composition of NaCMC, car:NaCMC ratio, and kaolin addition, but decreases with increase of crosslinker concentration. The equilibrium swelling degree of the beads were also in agreement with the release results. The carbaryl release experiments indicated that the transport deviates from Fickian to non-Fickian mechanism with an increase in car:NaCMC ratio.