The long-range objective of this research program is to develop methods for the correlation and prediction of the equilibrium thermodynamic behavior of pure polymers and polymer-solvent solutions. This is to include effects of pressure and temperature on density, vapor-liquid and liquid equilibria, and systems containing multiple solvents and/or polymers. In order to achieve this goal, extensive and reliable data are needed for the model developments. Data bases are being assembled containing evaluated literature data for the various types of systems. In order to pursue the development of a dependable group contribution model, more accurate data will be collected. The laboratory established under a previous NSF equipment grant is used for this purpose. A new group contribution model is being developed based on a lattice-fluid model of the polymer-solvent systems. The program is being coordinated with a complementary effort at the Technical University of Denmark.