Nanocomposite super‐swelling hydrogels with nanorod bentonite

Abstract

Abstract A modified bentonite (nanorod bentonite) was obtained from conventional bentonite by an ultrasonic treatment. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images indicated that modified bentonite comprised rod‐shape morphology without any change in the chemical structure confirmed by Fourier transform infrared (FTIR) spectroscopy and X‐ray diffraction (XRD) patterns. Novel super‐swelling hydrogels with nanocomposite structure were then prepared via solution polymerization of 2‐acrylamido‐2‐methylpropane sulfonic acid (AMPS) and ( N ‐[3‐(dimethylamino)propyl] methacrylamide) (DMAPMA) in the presence of the nanobentonite and a crosslinker. The DMAPMA consisted of either intercalant or monomer in the polymerization. The hydrogel products were characterized by FTIR, swelling studies, dynamic mechanical thermal analysis (DMTA), XRD, and rheological measurements. It was proposed that exfoliated and intercalated morphology were obtained at low and high‐nanobentonite contents, respectively. DMTA indicated that mechanical properties of the dried gel were improved with raising the clay content. In the water‐swollen state, storage modulus was considerably increased in nanocomposites having <8% of modified bentonite, and then it was decreased at the higher clay content due to interfering effect of the clay in polymerization progression. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011