SYNTHESIS, CHARACTERIZATION AND SWELLING BEHAVIOUR OF POLY(SODIUM ACRYLATE)/PALYGORSKITE SUPERABSORBENT COMPOSITES BASED ON PALYGORSKITE AND ORGANO-PALYGORSKITE

Novel superabsorbent composites based on partially neutralized acrylic acid (SA) and palygorskite (PLG) were synthesized by aqueous solution polymerization. The effects of PLG, organo-PLG (O-PLG) and the content of PLG in the copolymeric gels on the water sorption and the initial swelling rate in deionized water and saline solution (0.2 wt% NaCl(aq)) were studied. Experimental results indicate that the absorption in saline solution is smaller than that in deionized water. In comparison with a polymer prepared under clay-free conditions (415 gg(-1)), no considerable change in absorption is observed with incorporating 20.0 wt% PLG or 20.0 wt% O-PLG (368 gg(-1) or 356 gg(-1)), which significantly reduces in the cost of preparing superabsorbents. Plots of swelling against time have been found to fit mathematical relationships which are based on spring and dashpot models and are applied in the polymer field to viscoelastic systems. The thermal stability of the composites was found to be increased, and this was associated with the addition of palygorskite. In addition, the XRD patterns of poly(SA)/PLG and poly(SA)/O-PLG indicate the formation of a traditional microcomposite.