Thermodynamic Properties of Dilute Solutions of Cellulose Derivatives

Abstract

Values of the free energies, heats, and entropies of dilution are given for dilute solutions of cellulose acetates, cellulose nitrate, and ethyl cellulose in representative solvents. In a number of cases heats of dilution are positive and possibly related to the solubility parameter of the solvent. Entropies of dilution are less than those for comparable sys tems containing less polar, more flexible polymers. Values of the interaction parameter χ1 and the heat and entropy contributions, χh and χs , are calculated using the densities of the dry polymers. Some of the values of Xx appear to be unrealistic. Assumptions are made regarding solvation and the densities and volume fractions of the solvated polymers are estimated and used to obtain values of χ1,χ h. and χv for interaction between solvated polymer and solvent. Values of χs appear to be in better agreement with simpler lattice theories.