HYDROGELS BASED ON COPOLYMERS OF N-(2-HYDROXYETHYL)METHACRYLAMIDE, 2-HYDROXYETHYL METHACRYLATE, AND 4-T-BUTYL-2-HYDROXYCYCLOHEXYL METHACRYLATE

A nonionic, high water content, high-strength hydrogel based on N-(2-h ydroxy-ethyl) methacrylamide (HMA), 2-hydroxyethyl methacrylate (HEMA) , and a strengthening agent, 4-t-butyl-2-hydroxycyclohexyl methacrylat e (TBCM). The HMA was prepared by the reaction of methacryloyl chlorid e with ethanol amine. The copolymerization of HMA with varying concent rations of HEMA and TBCM resulted in transparent hydrogel films posses sing a wide range of mechanical and physical properties. A copolymer c omposition of 79 parts HMA, 20.7 parts TBCM, and 0.3 parts ethylene gl ycol dimethacrylate (EGDMA) gave a transparent, flexible film possessi ng a water content of 72.6%, a Young's modulus of 0.45 MPa, oxygen per meability of 28 barrers, and a tear strength of 28 N/m. In contrast, a copolymer composition of 40 parts HMA, 59.7 parts TBCM, and 0.3 parts EGDMA gave a hard, transparent film possessing a water content of 33% and a modulus of 504 MPa. (C) 1993 John Wiley & Sons, Inc.