ISBN 9783843913744

978-3-8439-1374-4, Reihe Thermodynamik

Felix T. Peters
A PC-SAFT Group Contribution Method for Polymers (Band 8)

261 Seiten, Dissertation Technische Universität Dortmund (2013), Softcover, A5

Zusammenfassung / Abstract

In the polymer industry the knowledge about the thermo-physical properties of pure polymers, copolymers, and their mixtures with solvents are indispensable for the process design and optimization.

To obtain the requested thermo-physical data, reliable thermodynamic models are preferred due to the considerable time-saving compared to laboratory experiments that are usually connected to high costs and a time-consuming measurement.

The PC-SAFT equation of state is one of the most-frequently used thermodynamic models to calculate thermo-physical properties of polymer systems. It requires at least three parameters for each component (polymer, solvent).

The solvent parameters are usually readily available in huge published parameter tables. In contrast to that, the polymer parameters have usually to be adjusted to experimental pure-polymer liquid densities and the experimental data of one binary, preferably liquid-liquid, polymer/solvent phase equilibrium (LLE). Furthermore, prior to the modeling of binary systems an additional binary interaction parameter (kij) between the polymer and the solvent has to be fitted to experimental data.

To avoid the time-consuming and expensive laboratory measurements, a group contribution method (GCM) was developed in this work. It allows the determination of the polymer parameters prior to the modeling by applying simple arithmetic and geometric mixing rules. To further reduce the number of parameters for multi-component polymer systems, a second GCM was developed for the calculation of polymer/solvent kij values based on a geometric mixing rule.

The modeling results by applying the two GCMs were in good agreement with experimental data of pure-polymer liquid densities, binary polymer/solvent, ternary polymer/solvent 1/solvent 2, and binary copolymer/solvent systems. For this purpose, LLE, vapor-liquid phase-equilibrium, and excess-enthalpy data were considered. Moreover, only little deviations occurred between the GCM results and the results obtained by the reference-method where the polymer parameters and the kij values were fitted to experimental pure-polymer and binary data prior to the modeling.