Swelling behavior of Sulfonated Polyacrylamide Nanocomposite Hydrogels in Electrolyte Salt Solutions

فاقد چكيده

Nanocomposite hydrogels were prepared by crosslinking of aqueous solutions of sulfonated polyacrylamide / sodium montmorillonite with chromium triacetate. The effect of nanoclay content on equilibrium swelling ratio in NaCl and CaCl2 solutions, ultimate storage modulus and crosslink density were evaluated. In addition, experimental swelling results of these nanocomposite gels (NC) was compared with predictions of Flory-Rehner theory modified by Vasheghani-Farahani et al.(V-F model). The limiting storage modulus of the NC gels decreased for montmorillonite content of 1000ppm, while for montmorillonite loading greater than 1000ppm, there is an increase in the limiting storage modulus of the NC gels. The equilibrium swelling ratio of the NC networks decreased with increase of montmorillonite content in both NaCl and CaCl2 solutions. In addition, the V-F model was sensitive to clay concentration and that the swelling data for NC gels in dilute salt solutions can be well represented by V-F model. However, with increasing salt concentration, theoretical predictions show some deviations from experimental results.