Preparation and characterization of cellulose-supported HEMA hydrogels

Cellulose fibre-supported hydrogels of HEMA were prepared by means of an ozone-induced graft polymerization process. The effect of various process parameters during ozone treatment on the ability to form hydroperoxides on the cellulose fibres was studied. Ozonation of water-swollen cellulose fibres with a humidified, saturated ozone/oxygen mixture resulted in a significant increase in hydroperoxide formation. The hydroperoxidized cellulose initiated graft polymerization of HEMA mostly in the pores of cellulose, leaving the surface incompletely covered, as detected by ESCA and AFM. The addition of a bifunctional crosslinking monomer, DEGDMA, not only increased the amount of add-on, but also 'led-out' the graft polymerization process from the pores onto the surface and then into the symmetrical spheres. (C) 1997 Elsevier Science Ltd.