Poly(vinyl alcohol) (PVA) was modified with phthalic and succinic anhydrides to give vinyl alcoholvinyl ester copolymers that contain carboxylate groups. These half-esters were then crosslinked by using the poly(ethylene glycol) (PEG) 400 diglycidylether. Low crosslinker/carboxylate ratios were used to obtain low degrees of crosslinking, so the capacity of the resulting hydrogel to absorb water was high. Water absorption was determined gravimetrically as a function of time at room temperature. The equilibrium swelling ratio and compressive modulus were characterized for all the resulting PVA hydrogels and related to the network structure. (C) 2003 Wiley Periodicals, Inc.