Effect of addition of saccharides on gelation of aqueous poly(vinyl alcohol) solutions

The properties of poly(vinyl alcohol) (PVA) hydrogels containing saccharides (D-xylose, D-fructose, D-glucose, and maltose) were examined. The effect of the addition of saccharides to PVA hydrogels on their melting temperatures was remarkable when the gels were chilled at 0 degrees C with saccharide contents above 40 g/dL. Particularly, the melting temperature was the highest for PVA hydrogels with glucose and above 73 degrees C at the polymer concentrations above 6 g/dL. Namely, the enthalpy of the thermal dissociation of the junctions of the spatial network Delta H was the highest of the four saccharides (glucose > fructose > maltose > xylose) and 150 kJ/mol for the hydrogels with the glucose content of 60 g/dL. The uniform preservation of saccharides and water in their gels were the highest for the gels with fructose during standing for a long time in air after freeze-drying. (C) 1999 John Wiley & Sons, Inc.