Extension of Flory-Huggins Theory to Satisfy the Hard Sphere Limit

In this work Flory-Huggins theory has been extended to satisfy the hard sphere limit. The resulting equations are used to correlate the solvent activity and to calculate the polymer size parameter. Based on the extended model new equations have been derived to predict the enthalpy and entropy of dilution of various polymer solutions with diverse molecular weights in different solvents. The results obtained from the extended Flory-Huggins theory are compared with those of the original theory and with the experimental data. The comparisons indicate that the proposed extension improves the predictability of the theory for thermodynamic properties of polymer solutions.