Department:
Green Chemical Technology
Project manager(s):
Year:
2003
Financial supporter:
Iranian Research Organization for Science and Technology
| By density measurements the excess volume of binary mixtures of polyethylene glycol, polypropylene glycol in solvents water and ethanol, and polyvinyl alcohol in solvent water were evaluated at different temperatures for various molecular weight of polymers. The excess volumer were correlated and expressed by a polynomial in terms of weight fraction of polymer. The activity of solvent was expressed in terms of three parts, namely excess internal energy, excess entropy and excess volume. The excess volume part was derived from the expression obtained in this work. The excess entropy part was derived from Flory's lattice model. The excess internal energy part was used a weight average of the excess volume and entropy parts. The results indicated good agreement between the activity of solvent calculated by the proposed model and the experimental data. The proposed model the advantage that with only simple density measurements the activity values which are necessary in the calculation of thermodynamic properties can be evaluated. |