| abstract |
Non-hydrolyzable, hydrophilic, heterocyclic cross-linking agents for cross-linking vinyl comonomers are provided. The cross-linked copolymers form optically transparent, high water content, and high refractive index hydrogels having long term stability which are useful as intraocular lenses and superabsorbents. The crosslinkers are selected from 4,6 divinyl pyrimidine, 2,5 divinyl pyrazine, 1,4 divinyl imidazole and 1,5 divinyl imidazole. |