Synthesis and properties of a novel double network nanocomposite hydrogel

A novel polyacrylamide/polyacrylic acid (PAAm/PAA) double network (DN) nanocomposite (NC) hydrogel had been synthesized by two‐step solution polymerization. The PAAm network was crosslinked by inorganic clay while the PAA network was crosslinked by a chemical crosslinker. The chemical structure of the network was confirmed by Fourier transform infrared (FTIR), X‐ray diffraction (XRD), and transmission electron microscopy (TEM). The swelling and mechanical strength properties of PAAm/PAA hydrogels were examined. The results showed that a DN hydrogel achieved both a high swelling capacity of 1219 g/g in deionized water and 124 g/g in 0.9 wt% NaCl solution and high compressive stress of 21.5 kPa in a high water content of 99.58%. Copyright © 2008 John Wiley & Sons, Ltd.