PREPARATION OF HYDROPHILIC POLYMER NETWORKS BY POST-CURING REACTION

Hydrophilic gels are a very important class of polymeric materials with extensive applications as biomedical products. The critical properties of hydrogels, such as sorption and desorption, mechanical behavior, swelling properties, etc., are controlled by network characteristics, i.e. degree of crosslinking and the density, distribution and length of crosslinks. Hydrogels prepared by copolymerization of 2-hydroxyethyl methacrylate (HEMA) with ethylene glycol dimethacrylate (EGDMA) have already been studied in detail. In this work, hydrophilic networks were prepared by crosslinking HEMA with EGDMA, and poly(2-hydroxy-ethel methacrylate) (PHEMA) with diphenylmethane-4,4'-diisocyanate (MDI). The swelling properties of both types of networks were studied and the differences in behavior were attributed to the different techniques applied for network formation.