CELLULOSE POLY(VINYL ALCOHOL) BLENDS .1. INFLUENCE OF MISCIBILITY ANDWATER-CONTENT ON RELAXATIONS

This contribution is concerned with cellulose/poly(vinyl alcohol) blen ds, and it concentrates on the influence of miscibility and the presen ce of water on relaxations. The blends were characterized by small and wide angle X-ray scattering as well as by dielectric and dynamic mech anical spectroscopy. They display no residual crystallinity and are ch aracterized by a molecular mixing of the components with microheteroge neities on a nanometer scale. The water is bonded yet mobile. A temper ature increase leads to an enhanced mobility of the water as well as t o the onset of main-chain rearrangements and of decomposition. A secon dary relaxation occurs in all blends: the relaxation behavior is simil ar for the blends and the pure cellulose. A major result is that the p resence of water influences the relaxation in the blends more strongly than the presence of the blend component poly(vinyl alcohol).