Superabsorbent polymeric materials. XII. Effect of montmorillonite on water absorbency for poly(sodium acrylate) and montmorillonite nanocomposite superabsorbents

A series of novel xerogels based on sodium acrylate (NaA), montmorillonite (MMT), and NN'-methylene-bisacrylamide (NMBA) were prepared by inverse suspension polymerization and water solution polymerization. The influences of pure MMT, intercalated MMT, the method of polymerization, and the content of the MMT in the copolymeric gels on the water absorbency and the initial absorption rate in deionized water and various salt solutions were investigated. Results showed that the water absorbency was increased by adding a small amount of the pure MMT into the copolymeric gels, but decreased by adding intercalated MMT into the gels. In addition, the water absorbency of the gels prepared by water solution polymerization was lower than that prepared by inverse suspension polymerization. (C) 2004 Wiley Periodicals, Inc.