STUDY OF MISCIBILITY OF POLY(VINYL ACETATE) AND POLY(VINYL ALCOHOL) BLENDS BY FLUORESCENCE SPECTROSCOPY

Secondary relaxations of poly(vinyl alcohol) (PVA), poly(vinyl acetate ) (PVAc), and their blends in different proportions (9:1, 1:1, and 1:9 ) were studied by photoluminescence of anthracene, fluorescein, and bo th probes dissolved in the polymer blends. The temperature of the glas s transition in the homopolymers was determined by the radiationless d eactivation of anthracene as T-g(PVAc) congruent to 304 K and the phot obleaching of fluorescein as T-g(PVA) congruent to 350 K. The relaxati on processes of the different phases of the polymer blends occur at te mperatures close to the homopolymers, which may be explained by the lo calization of each molecular probe within the matrix. These deactivati on curves, however, are not similar to those of the individual homopol ymers, suggesting a partial miscibility between these polymers. (C) 19 95 John Wiley and Sons, Inc.