Peculiarities in the hydration of cellulose in air and water suspensions as studied by H-1 NMR spectroscopy

Bound water layers in hydrated powders and aqueous suspensions of microcrys talline cellulose were investigated by H-1 NMR methods. The characteristics of such layers were calculated and the magnitude of the interfacial energy (gamma (s)) at the cellulose/water interface in an aqueous environment det ermined. It was found that the concentration of strongly bound water and th e value of gamma (s), were strongly dependent on the concentration of cellu lose in suspension. This is probably due to the strong interaction between cellulose particles. At very high suspension concentrations, the concentrat ion of water inside the cellulose filament decreased by more than three-tim es while the value of gamma (s) decreased from 31 J/g to 9 J/g as a result of surface forces.