NOVEL POLYURETHANE SILICONE HYDROGELS

Polyurethane hydrogel derived from polysiloxane-based ultraviolet-curable polyurethane prepolymers and hydrophilic monomers were prepared and their properties were evaluated. The polyurethane prepolymers used in this study contained different arrangements of hard and soft segments and were derived from isophorone diisocyanate, neopentyl glycol, diethylene glycol, 1,4-butanediol, hydroxy-terminated polydimethylsiloxane, and 2-hydroxyethyl methacrylates. The hydrophilic monomers used were 2-hydroxyethyl methacrylate and N,N-dimethyl acrylamide. All compositions can be cured under ultraviolet (UV) and form hydrogels after hydration. The oxygen permeabilities of the hydrogels are much higher than those of nonsilicone hydrogels and decreased as the water contents increased. The tear strengths and moduli decreased as the water contents of the hydrogels increased. All hydrogels prepared showed good hydrolytic stability and did not absorb lysozyme. (C) 1995 John Wiley & Sons, Inc.