High water-absorbent copolymers comprising acrylic acid (AA) and acrylamide (AM) were prepared in the presence of a crosslinking agent, monofunctional aldehyde, by a solution polymerization technique using a redox initiation system. Such copolymers have very high water absorbency and absorbing kinetics to the distilled water. The copolymer formed which absorbed about 900 g water/g dry copolymer was used to study the influence of sodium chloride on the absorption capacity at 24 degrees C. The swelling of this copolymer was studied in alcohol/water mixtures of increasing alcohol content at 294, 304, and 314 K. The main transition for ethanol/water and methanol/ water mixtures is a rapid decrease of the retention capacity of the copolymer at 50-60 vol % ethanol and 55-65 vol % methanol, respectively. Swelling in distilled water at different temperatures (T) and the effect of solvent composition were also studied. Among the variables examined were initiator concentration, polymerization temperature, and amount of AM in the copolymer.