Swelling of superabsorbents polymers in an aqueous medium

The polymers studied are superabsorbents materials. They were synthesized by inverse suspension polymerisation of acrylic acid. The polymers studied, X10 and X5, are different in their degree of ionisation. In fact, our objective was to increase the amount of water that may be stored by the polymer. In this article, we investigated not only the effect of temperature and pH on the satured water absorbency of polymers X10 and X5, but also various swelling behaviours of polymer X10 in different saline solutions. The results show that for temperature ranging from 10 to 90°C, the effect of temperature on the satured water absorbency is rather limited when the superabsorbent is swelled by distilled water. Further, water absorbency of X10 and X5 is strongly affected by the pH value. The results also indicate that saline solutions can weaken the swelling abilities of the polymer X10. Water absorbency of polymer X10 in aqueous chloride salt solutions has the following order: Na⁺ = K⁺= NH > Ca²⁺ = Mg²⁺ all through the range of investigated concentration. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010