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 both probes dissolved in the polymer blends. The temperature of the glass transition in the homopolymers was determined by the radiationless deactivation of anthracene as T-g(PVAc) congruent to 304 K and the photobleaching of fluorescein as T-g(PVA) congruent to 350 K. The relaxation processes of the different phases of the polymer blends occur at temperatures close to the homopolymers, which may be explained by the localization of each molecular probe within the matrix. These deactivation curves, however, are not similar to those of the individual homopolymers, suggesting a partial miscibility between these polymers. (C) 1995 John Wiley and Sons, Inc.55688990