title: Structure of aqueous solutions of microcrystalline cellulose/sodium hydroxide below 0 degrees C and the limit of cellulose dissolution.
abstract: The aim of the paper is to investigate the structure of solutions of microcrystalline cellulose in NaOH/water mixtures and to determine the limit of cellulose solubility. The binary NaOH/water and the ternary cellulose/NaOH/water phase diagrams in the area of cellulose dissolution (7-10% NaOH below 0 degrees C) are studied by DSC. The NaOH/water binary phase diagram has a simple eutectic behavior. Because of the existence of this eutectic structure, it is possible to measure the influence of the addition of pure low molar mass microcrystalline cellulose. This shows that a minimum of four NaOH molecules should be linked to one anhydroglucose unit to allow for the dissolution of microcrystalline cellulose. The proportions between bound Avicel, NaOH, and water molecules as a function of cellulose concentrations are calculated. A tentative explanation about the origin of the dissolving power of NaOH/water is given.
authors.affiliation: Centre de Mise en Forme des Matériaux, Ecole des Mines de Paris, UMR CNRS 7635, BP 207, Sophia-Antipolis, France.
authors.forename: Magali
authors.initials: M
authors.lastname: Egal
authors.forename: Tatiana
authors.initials: T
authors.lastname: Budtova
authors.forename: Patrick
authors.initials: P
authors.lastname: Navard
mesh_terms: D002482:Cellulose / Q000737:chemistry*; D003460:Crystallization; D012972:Sodium Hydroxide / Q000737:chemistry*; D012995:Solubility; D014867:Water
chemical_list: D014867:Water; D012972:Sodium Hydroxide; D002482:Cellulose