Modeling Phase Equilibria of polyethylene solutions with the Sanchez-Lacombe Equation of State

Predicting polymer solution’s phase behaviors is very important in polymerization and separation processes. In this paper, cloud point curves of polyethylene (PE) in ethylene and polyethylene in normal hexane are studied. Since polymers are made of chains with different length, continuous thermodynamics method is used for calculations. A continuous distribution function is necessary to describe polymers. Schulz- Flory distribution function is used to show polydispersity of polyethylene. Polyethylene systems are modeled using Sanchez-Lacombe (SL) equation of state. The method of equality of chemical potentials is used for calculations. Required equations are rewritten in the continuous form. The results are acceptable in compare with experimental data.