| Abstract: | Continuous thermodynamics is a suitable concept for performing phase equilibrium calculations of polydisperse systems such as polymer solutions or polymer mixtures. In contrast to the traditional pseudo-component method the continuous molar mass distribution density function obtained by fractionation or gel permeation chromatography is used directly for thermodynamic calculations. This paper describes the application of continuous thermodynamics to calculate cloud-point curves, shadow curves and coexistence curves for solutions and mixtures of homopolymers and random copolymers. Particular attention is devoted to special problems such as fractionation or the transition from polymers to oligomers requiring the application of sophisticated Gibbs energy functions. In all cases the use of continuous thermodynamics leads to a drastic reduction of the required computer time. For Schulz-Flory distributions the occurring integrals often may be calculated analytically leading to simple closed end formulas. |
