Silicone hydrogels with interpenetrating network structure prepared by simultaneous free-radical/cationic hybrid polymerizations

摘要

Silicone hydrogels with interpenetrating network (IPN) structure were prepared by ultraviolet (UV)-initiated simultaneous free-radical/cationic polymerizations in order to develop contact lens with high performances. The polymerization mechanism was investigated by gel fraction method using polymerization of 2-hydroxyethyl methacrylate (HEMA) and 4-hydroxybutyl vinyl ether (HBVE) as a model. The results showed that HEMA and crosslinker ethylene glycol dimethacrylate (EGDMA) polymerized by free-radical mechanism, while HBVE and crosslinker triethylene glycol divinyl ether (DVE-3) polymerized by cationic mechanism. The IPN silicone hydrogels were then prepared by UV-initiated hybrid photopolymerization of monomers including HEMA and bitelechelic polydimethylsiloxane bearing vinyl ethers end-groups (VS) in the presence of free-radical and cationic photoinitiators. Physiochemical properties such as optical properties, ion permeability, contact angle, and mechanical properties of the silicone hydrogels were characterized by UV spectroscopy, ionoflux technique, and tensile tester. The results revealed that the water content, surface wettability, and ion permeability of the hydrogels increased, but the tensile strength and Young's modulus decreased with the increase of the HEMA content.