HYDROPHILIC SPONGES BASED ON 2-HYDROXYETHYL METHACRYLATE .3. EFFECT OF INCORPORATING A HYDROPHILIC CROSS-LINKING AGENT ON THE EQUILIBRIUM WATER-CONTENT AND PORE STRUCTURE

The effect of using a hydrophilic crosslinking agent (divinyl glycol, DVG) on 2-hydroxyethyl methacrylate (HEMA) sponge swelling and pore mo rphology was evaluated. Concentrations of crosslinking agent, redox in itiators and HEMA (75-90 wt%) in the initial aqueous monomer mixture w ere varied. Anomalous sponge swelling behaviour, together with the for mation of nonuniform stratified sponges was rationalised in terms of t he assumed disparate free radical reactivities of DVG and HEMA. Enviro nmental scanning electron microscopy indicated that the stratified spo nges did not exhibit suitable porosity for biomedical use.