Swelling characterization of novel ternary semi-IPNs: acrylamide/1-vinylimidazole/PEG hydrogels

New ternary semi interpenetrating polymer networks (semi-IPNs) systems containing acrylamide (AAm), 1-vinylimidazole (VI) and poly (ethylene glycol) (PEG) have been prepared. AAm/Vl hydrogels and semi-IPN's, poly (AAm/VI/PEG) with 0.25, 0.50, 0.75 and 1.00 g of PEG (per 1.00 g AAm) were prepared by free radical solution polymerization in aqueous solution of AAm with VI as comonomer and a multifunctional crosslinker such as 1,4 butanediol dimethacrylate (BDMA). Swelling experiments were performed in water at 25 degrees C, gravimetrically. The influence of VI and PEG content in hydrogels were examined. AAm/VI and AAm/VI/PEG hydrogels showed large extents of swelling in aqueous media, the swelling being highly dependent on the chemical composition of the hydrogels. Percentage swelling ratio of AAm/VI hydrogels and AAm/VI/PEG hydrogels was shown as 650-4167%. The values of equilibrium water content (EWC) of the hydrogels are between 0.8990 and 0.9750. Diffusion behavior was investigated. Water diffusion into hydrogels was found to be non-Fickian in character. Copyright (C) 2007 John Wiley & Sons, Ltd.