A NOVEL NONIONIC HYDROGEL FROM 2-METHYL-2-OXAZOLINE .3. POLYOXAZOLINE HAVING A COUMARIN MOIETY AS A PENDANT GROUP - SYNTHESIS AND PHOTOGELATION

Polyoxazoline having a coumarin moiety in the pendant group was synthesized by the reaction of partially hydrolyzed poly(iV-acetylethylenimine) with (7-coumaryloxy)acetic acid in the presence of dicyclohexylcarbodiimide (DCC) as a condensing agent. The photosensitive polyoxazoline was irradiated with a 450-W high-pressure Hg lamp (X > 300 nm) for 7 h to produce polyoxazoline gels. These gels were swollen in water and showed characteristic properties of a hydrogel. Their equilibrium degree of swelling in water was controlled by the irradiation time and also by the degree of substitution of the coumarin moieties. The water uptake was up to 20 times the weight of the dry gel. The photocleavage reaction of the gel, which was monitored by its UV spectrum, was carried out by irradiation with a low-pressure Hg lamp (X ~ 253 nm). © 1990, American Chemical Society. All rights reserved.