The Statistical Associating Fluid Theory (SAFT) equation of state and the Perturbed-Hard-Sphere-Chain (PHSC) equation of state are available as part of the Polymer add-on module for PRO/II.
Compared to commonly-used cubic equations of state, both SAFT and PHSC EOS are applicable to a wider variety of systems. These encompass systems that include small and medium molecules (e.g. fluids), as well as large substances, such as polymers and copolymers. Also, they apply to a wider (entire) range of fluid conditions including vapor, liquid, and supercritical regions.
Both SAFT and PHSC EOS allow users to model vapor-liquid and liquid-liquid equilibria in systems containing polymers and solvents. They are also uniquely applicable to high-pressure polymer-supercritical solvent systems. Overall, they are characterized by a much higher accuracy of phase equilibrium correlation than any existing thermodynamic models for polymer systems.
The SAFT and PHSC equations of state have three pure parameters: (1) segment number per molecule r, (2) segment size (diameter) s, and (3) non-bonded segment-segment interaction energy e. They also incorporate a binary parameter, kij. For mixtures, additional parameters eij and sij are needed for each unlike pair of components (i¹j). They are calculated from combining rules.
The SAFT equation of state has been developed to model vapor-liquid and liquid-liquid equilibria in polymer systems. It is applicable to systems of small and medium molecules as well as large substances such as polymers and copolymers. The equation applies in vapor, liquid and supercritical regions over a wide range of fluid conditions.
The interaction energy, diameter, and chain length are required for components and segments. These terms are either calculated or supplied in the Pure Species Parameters Window.
Polymer segments and components must be defined in the Definition of Polymer Components Window.