Journal of Polymer Science Part A: Polymer Chemistry, Vol.45, No.10, 1868-1877, 2007
Photolytic transformation of aryl benzobisoxazole and aryl benzobisthiazole compounds into carbon dioxide
Solid-state aryl benzobisoxazole and aryl benzobisthiazole compounds photolyzed in the presence of O-2 undergo cleavage to produce benzobisoxazoles (or benzobisthiazoles), benzonitriles, and benzamides. A very high percentage of the carbon atoms in one of the two segments from chain cleavage are converted to CO2. This very unusual observation has been carefully confirmed by gas chromatography/mass spectroscopy analysis of the gaseous components in the photolysis vessel before and after photolysis, labeling experiments, and the correlation of the mass reduction in photolyzed polymers and the amount of CO2 that evolves. The rate of CO2 generation is used to compare the relative photostability of aryl benzobisoxazole and aryl benzobisthiazole model compounds, films, and fibers. (c) 2006 Wiley Periodicals, Inc.
Keywords:carbon dioxide;degradation;electron transfer;high temperature materials;photochemistry;photolysis;photostability;polyaromatics;polybenzobisoxazoles;polybenzobisthiazoles;poly(phenylene oxide);stabilization