| abstract |
Copolymers comprising acrylic or methacrylic acid and methyl methacrylate are neutralized by the addition of cyclic alkylene imines, preferably ethylene imine, to form a product which is capable of absorbing large amounts of material soluble in water, and slowly releasing those materials. The fundamental copolymer may be modified by the addition of cross-linking agents, chain terminators, plasticizers, etc., prior to treatment with the alkylene imine. The treated copolymers are particularly useful in the formation of contact lenses for the application of medicinals to the eye, and for other depot materials. |