NONIONIC HYDROGELS BASED ON POLY(METHYL TRIETHYLENE GLYCOL VINYL ETHER)

Abstract

Two types of nonionic hydrogels have been synthesized in the present study by cationic polymerization. The first type was prepared by precipitative copolymerization of methyl triethylene glycol vinyl ether (MTVE) and tetraethylene glycol divinyl ether (TDVE). Methyl tert-butyl ether (MTBE) was used as a polymerization medium, because it is a good solvent for the monomers but not a solvent for their copolymer. The swelling capacity of the copolymers was found to reach its maximum (10 g/g), when the content of TDVE used as a crosslinker was 5 wt%. Another type was synthesized by cationic copolymerization of MTVE and vinyloxyethyl methacrylate (VEM) followed by the radical crosslinking. The monomers were first copolymerized in dichloromethane at −78°C to afford a water-soluble copolymer in almost quantitative yield. Then the copolymers were crosslinked using ammonium persulfate as a radical initiator. The crosslinked products containing 0.3 wt% of VEM exhibited maximum swellability in water (24 g/g). Both types of hydrogels were shown to be stable in the presence of an electrolyte salt as well as over a wide pH range of aqueous media.