Preparation and characterization of crosslinked alginate-CMC beads for controlled release of nitrate salt

Carboxymethyl cellulose (CMC)/sodium alginate (SA) hydrogel beads were successfully prepared by Ca2+ ions crosslinking followed by gamma irradiation. The factors affecting beads formation are the composition of SA in the blend and concentration of calcium chloride as a crosslinking agent. The results indicated that the addition of CMC to SA increases the swelling (%) upto (1: 3) (CMC: SA) ratio. The effect of different irradiation doses (2.5, 5, and 10 kGy) on swelling (%) was studied. At low doses, swelling (%) decreases upto 5 kGy then starts to increase at 10 kGy. The degree of the swelling (%) and release (%) of ammonium nitrate salt from beads were investigated under different pH (1.2, 5 and 7). The beads were characterized by FTIR, SEM and TGA to investigate molecular structure, morphology and thermal stability of beads.