Structural changes of cellulose dissolved in molten salt hydrates

Abstract

The behavior of cellulose in molten salt hydrates, e. g., LiClO4*3 H2O, ZnCl2*4 H2O, LiCl*5 H2O and mixtures of thiocyanates was investigated. Melts, which give rise to a swelling or dissolution of the cellulose were the focus of interest. The melt composition and species, the water amount and the structure of the coordination sphere of the cation of the molten salt hydrate as well as the acidity influence the solubility of the cellulose in molten salt systems. The interactions between cellulose and species of the melts were determined by solution state 13C NMR measurements at temperatures between 65°C and 140°C. Each regenerated cellulose showed other but specific properties which were characterized by wide angle X-ray Scattering (WAXS), solid-state NMR (13C CP/MAS NMR), molecular weight distribution, surface-area determinations and scanning electron microscopy (SEM).