Synthesis and properties of hydrogels from poly (vinyl alcohol) and ethylenediaminetetraacetic dianhydride

Crosslinked poly(vinyl alcohol) with different amounts of ethylenediaminetetraacetic dianhydride was synthesized and characterized by elemental analysis, C-13-NMR and IR spectroscopy. The average molecular weight between crosslinks ((M) over bar (c)), the mesh size (xi) and the crosslinking density (rho (x)) were calculated from swelling studies and related to OH/anhydride ratios. The polymer-solvent interaction parameter (chi) was calculated by mechanical measurements. The swelling behaviour of hydrogels was studied as a function of the crosslinking degree. A kinetic study of the absorption determined the transport mechanism. The diffusion coefficient was calculated for the Fickian mechanism, and the swelling behaviours were analyzed in buffer solutions at various pH and temperature ranges. Swelling ratios were relatively high and sensitive to pH and ionic strength, but not to temperature. (C) 2001 Published by Elsevier Science Ltd.