Water absorbency behaviour of acrylamide (AAm)/2,3-dihydroxybutanedioic acid (DBA) hydrogels synthesized by, gamma-radiation crosslinking of AAm and DBA in an aqueous solution was investigated. Different amounts of DBA containing AArn/DBA hydrogels were obtained in the form of rods via a radiation technique. Swelling experiments were performed in water at 25 degreesC, gravimetrically. The influence of absorbed dose and DBA content of the hydrogels on swelling properties were examined. The hydrogels showed enormous swelling in an aqueous medium and displayed swelling characteristics which were highly dependent on the chemical composition of the hydrogels and irradiation dose. Diffusion behaviour and some swelling kinetic parameters were investigated. The values of the weight swelling ratio of AAm/DBA hydrogels were between 8.34 and 15.16, while the values of the weight swelling ratio of pure AAm hydrogels were between 7.58 and 8.28. Water diffusion into hydrogels was found to be non-Fickian in character. Equilibrium water contents of the hydrogel systems were changed between 0.8681 and 0.9340. (C) 2004 Elsevier B.V. All rights reserved.