Reversible Swelling/Deswelling Characteristics of Ethylene Glycol Dimethacrylate Cross-Linked Poly(acrylic acid-co-sodium acrylate-co-acrylamide) Superabsorbents
(10918–10927) Industrial & Engineering Chemistry Research 50 #19 (2011)
Shukla and Madras of the Indian Institute of Science, India, synthesized poly(acrylic acid-co-sodium acrylate-co-acrylamide) superabsorbent polymers (SAPs) cross-linked with ethylene glycol dimethacrylate (EGDMA) by inverse suspension polymerization. The SAPs were swollen in DI water, and it was found that the equilibrium swelling capacities varied with the acrylamide content.  The equilibrium swelling capacity of the SAPs was found to decrease with increasing concentration of added electrolyte in the swelling medium. A first order model was used to describe the kinetics of swelling/deswelling, and the equilibrium swelling capacity, limiting swelling capacity, and swelling/deswelling rate coefficients were determined.  (RDC 10/11/2011)

Acrylamide–itaconic acid superabsorbent polymers and superabsorbent polymer/mica nanocomposites
(635–647)Polymers for Advanced Technologies 22 #5 (2011)
Foungfung et al of Chulalongkorn University, Thailand, synthesized superabsorbent polymer acrylamide (AM)/itaconic acid (IA) and its nanocomposite by redox polymerization in an aqueous solution of both monomers with mica used as an inorganic additive.  The water absorbency and the artificial urine absorbency of the composite with an AM-to-IA mole ratio of 95:5, 0.2% mol N-MBA, and 5% w/w mica were 748 ± 5 and 76 ± 2 g g−1, respectively, whilst the neat copolymer achieved only 640 ± 7 and 72 ± 2 g g−1 in water and artificial urine, respectively.  (RDC 6/9/2011)

Utilization of starch and montmorrilonite for the preparation of superabsorbent nanocomposite
(2406–2412)Journal of Applied Polymer  Science 121 #4 (2011)
Zhou, Zhao and Zhou of the Southwest Petroleum University, China, used starch and montmorillonite (MMT) as raw materials for synthesizing starch-graft-poly[acrylamide (AM)–acrylic acid (AA)]/MMT superabsorbent nanocomposite by graft and intercalation copolymerization reaction of starch, AM, and AA in the presence of organic MMT micropowder in aqueous solution.  The superabsorbent nanocomposite synthesized under optimal synthesis conditions exhibits absorption of 1120 g H2O/g sample and 128 g H2O/g sample in deionized water and in 0.9 wt % NaCl solution, respectively.  IR spectra showed that the graft copolymerization between OH groups on MMT and monomers took place during the reaction, and that crystal interlayer was pulled open in the superabsorbent nanocomposite.  X-ray diffraction analysis showed that the crystal interlayer of MMT was pulled open to 2.73 nm, and thus formed nanometer exfoliation composite material. Thermogravimetric analysis showed that starch-graft-poly (AM–AA) superabsorbent nanocomposite (8 wt % MMT) has good thermal stability. This superabsorbent nanocomposite with excellent water absorbency and water retention, being biodegradable in nature, economical and environment friendly, could be especially useful in industry, agricultural, and horticultural applications.  (RDC 5/23/2011)