Dissolution of Cellulose in Aqueous Alkaline Solutions with Added Urea and Thiourea

The solubility of wood cellulose of various molecular weights in aqueous NaOH solutions with added urea and thiourea was studied with variable temperature, solvent composition, and sequence of dissolution stages. It was shown that cellulose of average degree of polymerization up to 500-600 dissolved. Thermally reversible gels formed in solutions held at 20°C for 2 d. The structural organization of cellulose-hydrate films prepared from the solutions was studied using IR spectroscopy and x-ray diffraction.