Synthesis of Poly[4-arylazo-3-hydroxy-2-naphthoic m-methacrylamidoanilides] and their Light Fastness

Abstract

To investigate the composition and light fastness of homopolymer of polymerizable group containing Naphthol AS series azo dyes, poly[4-arylazo-3-hydroxy-2-naphthoic m-methacryl- amidoanilides] were prepared from the homopolymerization of monomeric dyes synthesized by the coupling reaction of 3-hydroxy-2-naphthoic m-methacryla mideoanilide with aromatic diazonium salts. The polymeric dyes containing the following- aryl groups were prepared, namely, the aryl groups were: 2-CH₃0-5-(C₂H₅)₂NSO₂C₆H₃, 2-CH₃-4-ClC₆H₃, 2-CH₃0-5-C₆H₅CH₂SO₂C₆ H₄, 3-ClC₆H₄, C₆H₅.

It was proved from GPC analysis that the polymeric dyes possessed a broad distribution of molecular weight but main components in the polymeric dyes were tetramer-hexamer. And it was confirmed from visible and infrared absorption spectra that a content of keto tautomer in the polymeric dye decreased and a content of enol tautomer in the polymeric dye increased, as compared with that of the monomeric dye.
The comparison of light fastness of the polymeric and monomeric dyes were caraied out in MMA resin cast film and in baked melamine-alkyde paint, as a result, light fastness of the polymeric dyes were poor than that of the corresponding monomeric dyes. It was presumed as a reason that the poor light fastness was yielded from a change of the proportion of tautomer in the polymeric dye.