Utilization of starch and clay for the preparation of superabsorbent composite

Starch and attapulgite were utilized as raw material for synthesizing starch-graft-poly(acrylic acid)/attapulgite superabsorbent composite by graft copolymerization reaction of starch and acrylic acid (AA) in the presence of attapulgite micropowder in aqueous solution. Major factors affecting on water absorbency such as weight ratio of AA to starch, initial monomer concentration, neutralization degree of AA, amount of crosslinker, initiator and attapulgite were investigated. The superabsorbent composite synthesized under optimal synthesis conditions with an attapulgite content of 10 wt% exhibit absorption of 1077 g H2O/g sample and 61 g H2O/g sample in distilled water and in 0.9 wt% NaCl solution, respectively. This superabsorbent composite with excellent water absorbency and water retention under load, being biodegradable in nature, economical and environment-friendly, could be especially useful in agricultural and horticultural applications. (c) 2006 Published by Elsevier Ltd.