Salep-g-poly(sodium acrylate)/alumina as an environmental-sensitive biopolymer superabsorbent composite: Synthesis and investigation of its swelling behavior

A novel kind of a biopolymer-based superabsorbent composite, salep-g-poly(sodium acrylate)/alumina, was prepared from salep, sodium acrylate, and alumina by aqueous polymerization, using N,N′-methylenebisacrylamide (MBA) as a cross-linker and ammonium persulfate (APS) as an initiator. The reaction parameters [i.e., acrylic acid (AA), MBA, APS amounts, and neutralization percentage of AA as well as alumina/salep weight ratio] affecting the water absorbency of the hydrogel composite were optimized using systematic method to achieve a composite with high swelling capacity as possible. The swelling behavior of optimum superabsorbent composite was measured in various pH solutions. In addition, swelling kinetics, swelling in various NaCl concentrations, swelling in various solvents, and the absorbency underload were investigated. Also, pH-reversibility and the on–off switching behaviors of the composite in various environments were investigated. © 2011 Wiley Periodicals, Inc. Adv Polym Techn 31: 41–51, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/adv.20233