AIChE Journal, Vol.48, No.6, 1284-1291, 2002
Solubilities of nonvolatile solutes in polymers from molecular thermodynamics
Because there is no simple, general method for measuring solubilities of nonvolatile solutes in a polymer, this work presents a thermodynamic framework for estimating such solubilities from infinite-dilution distribution-coefficient data for aqueous solutions of the solute in equilibrium with the polymer. The experimental infinite-dilution distribution coefficient is related to that calculated from a molecular-thermodynamic model (Flory-Huggins). The three binary Flory parameters are obtained from water-solute and water-polymer data, and from the solute's distribution coefficient. Solubilities of 19 nonvolatile aromatic solutes were estimated in three polymers: ethyl-vinyl acetate copolymer (EVAc) with 33 (EVAc33), 45 (EVAc45) wt.% vinyl acetate content, and poly(vinyl acetate) (PVAc) at 25degreesC, where most of the solutes arc solids. For some of these systems, predicted solubilities are compared with new experimental results. The calculations reported here may be useful for various applications, including the design of membrane processes or drug-delivery systems, and for packaging technology for foods, chemicals, and pharmaceuticals.