The provision of thermodynamic properties is essential for the design of optimal processes in industry. In this manuscript, five examples from the thermophysical-property group of Bayer Technology Services (BTS) illustrate the provision of thermodynamic properties of polymer systems in industry: (1) Experimental determination of high-pressure VLLE for the separation of solvent from polymer after solution polymerisation without the necessity of evaporation. (2) Basics of an apparatus and technique for the determination of VLE and diffusion coefficients in polymers according to a pressure decay method. (3) Usage of inverse gas chromatography (IGC) for the determination of VLE and diffusion coefficients in polymers. (4) Correction of data from a calorimeter according to a thermodynamic model in order to obtain heat capacities, c(P), of pure solvents and polymer + solvent mixtures. (5) Usage of statistical associating fluid theory (SAFT) in order to model a polymer + solvent system with strong specific interactions including self-association and cross-association. (C) 2003 Elsevier B.V. All rights reserved.