POSITRON-ANNIHILATION LIFETIME STUDIES OF SOL-GEL TRANSITION OF CARRAGEENAN GELS

Positron annihilation lifetime measurement was applied to study the so l-gel transition of anionic polysaccharide aqueous solutions in terms of free-volume parameters the size, intensity, and size distribution o f free volumes of the gelation of K-form kappa-carrageenan solutions a s a function of temperature. Slight variations of free volume size and intensity against temperature were observed near 295 K. The correlati on of free-volume data with other physical properties vibrational spec tra (IR and Raman), conductivity, SAXS, elastic measurement, different ial scanning calorimetry were investigated to understand the mechanism of sol-gel transition of carrageenan.