Water sorption kinetics of superabsorbent hydrogels of saponified cassava starch‐graft‐poly(acrylamide)

Abstract

Superabsorbent polymers (SAPs) are hydrophilic polymeric networks that can absorb, swell and retain large quantity of water and other physiological fluids. In this paper, the water sorption pattern and kinetics of cassava starch based SAP hydrogels were studied under different conditions of swelling such as soaking duration, pH, presence of salts, and particle size of the hydrogel. The kinetics was studied using Voigt‐based viscoelastic model to determine the rate parameter and the swelling rate (SR). It was noted that under all conditions, the water sorption followed a second order kinetics. The absorbency was directly proportional to the rate of swelling. But when the sample was allowed to swell in aqueous solutions of CaCl2 and AlCl3, the absorbency as well as the SR was irregular. The particle size also had significant effect on water absorption by the SAP and the polymer with smaller particles showed more absorption than those with larger particle size. The solvent induced phase transition of the superabsorbent hydrogel was also studied.

Superabsorbent hydrogels based on polysaccharides for application in agriculture as soil conditioner and nutrient carrier: A review

“…In recent years, SH incorporating polysaccharides have been widely studied [47][48][49], because they appear as viable ecologic and economically alternatives, aiming at soil conditioning [50]. Other characteristics which have been assigned for the use of polysaccharide-based SH are their nontoxicity, biodegradability, availability, and efficiency of application [51].…”

Effects of chain structures of corn starches on starch‐based superabsorbent polymers

“…Subsequently, Fanta et al prepared alkali‐hydrolyzed starch‐graft‐polyacrylonitrile, allowing the industrial production of SAPs. Since then, starch‐based SAPs have been developed by grafting starch with vinyl monomers, such as acrylic acid (AA) , acrylonitrile, acrylamide (AM) , sulfonic monomers, and other monomers.…”

The effect of swelling time on rheological properties of hydrogels, consisting of high -amylose carboxymethyl corn starch and acrylic polymers

“…Due to non‐biodegrability of acrylic polymers, attempts have been made to instead use natural polymers in the synthesis of superabsorbent polymers. Monomers such as acrylic acid , acrylamide acrylonitrile , etc. are commonly used for graft copolymerization of vinyl monomers onto a polysaccharide backbone .…”

“…are commonly used for graft copolymerization of vinyl monomers onto a polysaccharide backbone . Starch , cellulose , hyaluronan , dextran , and other polysaccharides have been reported in literature as suitable renewable sources for the production of biodegradable hydrogels.…”