Synthesis and properties of new polyurethane ionomers. I. Photosensitive cationomers with triazene units

New bifunctional triazene compounds 1-(m-hydroxymethyl)phenyl-3-(2-hydroxyethyl)-3-methyltriaz(l)ene and 1-p-nitrophenyl-3,3-di(2-hydroxyethyl)triaz(l)ene as intermediates in polyurethane synthesis were prepared. Photosensitive polyetherurethane cationomers based on poly(tetrameth-ylene oxide) diol of 2,000 average molecular weight, tolylene-2,4-diisocyanate, and N-methyldiethanolamine/triazene diols, as cochain extender, followed by a quaternization with benzyl chloride, were synthesized and characterized. Upon UV irradiation, feniltriazene chromophore in monomer and both polymers (ionomeric or nonionomeric type) is irreversibly cleaved, as evidenced in photolytic and kinetic studies. The rate constant of photolysis in ionomer film was lower than for the corresponding nonionic film. A positive pattern can then be developed by treatment with CHCl3 that dissolves the exposed zone, while the unexposed area remains resistant and insoluble. By incorporating side nitrofeniltriazene groups, photostable polyurethanes were obtained. (C) 2003 Wiley Periodicals, Inc.