Modelling of swelling of PVA hydrogels considering non-ideal mixing behaviour of PVA and water.

Abstract

Poly(vinyl alcohol) (PVA) hydrogel microbeads are widely used as embolization agents for the treatment of cancer infiltering organs. The success of embolization procedures depends strongly on the swelling properties of the hydrogels. PVAhydrogels can be understood as non-ideal mixtures of PVA and water. Here, the sum of PVA and water volumes is differentthan the volume of their resulting mixture. The correlation between volumetric and mass swelling of PVA and water ishighly relevant to several technological issues. In the present contribution, the water up take (WU), the most importantcharacteristic of PVA hydrogel microbeads intended for use as embolic agents, was investigated considering the hydrogelas a non-ideal mixture of PVA and water. Hydrogel microbeads were obtained by chemical crosslinking of PVA withglutaraldehyde (GA) in emulsion. The structure of resulting microbeads was investigated using FT-IR, SEM and digitalimage analysis. The volumetric and mass swelling of the microbeads in water were followed by optical microscopy andgravimetric studies, respectively. Additionally, a WU model for hydrogels where the polymer and water behave as nonidealmixtures is presented.