Modeling of the branching influence on liquid–liquid equilibrium of binary and ternary polymer solutions by lattice–cluster theory

• Published in: The Journal of chemical thermodynamics Vol. 62; pp. 56 - 63
• Main Authors: Browarzik, Dieter, Langenbach, Kai, Enders, Sabine, Browarzik, Christina
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.07.2013
• Subjects: Hyperbranched polymers; Lattice–cluster theory; Liquid–liquid equilibrium; Method of calculation; Ternary systems; Liquid–liquid equilibrium; Ternary systems; Lattice–cluster theory; Hyperbranched polymers; Method of calculation
• ISSN: 0021-9614; 1096-3626
• DOI: 10.1016/j.jct.2013.02.018

► Liquid–liquid equilibrium (LLE) is calculated with the lattice–cluster theory (LCT). ► Equations of the LCT are reduced to only three geometrical parameters. ► Branching influence on the LLE is modeled for binary and ternary polymer solutions. ► Branched and linear solvents and polymers are compared in their influence on LLE. ► Solutions of branched polymers in branched solvents show the best miscibility. The liquid–liquid equilibrium (LLE) of ternary model systems of the type solvent A+polymer B+solvent C is treated in the framework of lattice–cluster theory (LCT). There are a linear and a branched type of A-molecules as well as a linear and two types of strongly branched polymer molecules. The C-molecules are assumed to occupy only one lattice site. For nine binary and six ternary polymer solutions the branching influence on LLE is discussed. Currently, the LCT is the most useful model to take the architecture of the molecules into account. However, particularly for ternary systems the model is not comfortable because of the very numerous terms of the Gibbs energy. Using some relationships between the geometrical parameters of the model a considerable simplification is possible. In this paper the new and simpler equations of the LCT are presented. For comparison with experimental data critical temperatures of solutions of linear and branched polyethylene samples in diphenyl ether are calculated.