Phase relationships and thermodynamic interactions of isotactic poly(1-butene) and organic solvent systems.
Isotactic crystalline low-molecular-weight poly(1-butene), iPBu-1, was synthesised by using a metallocene catalyst. The molecular weight was determined by GPC. The chemical structure of iPBu-1 was verified by using high-temperature (13)C NMR spectroscopy and the thermal properties by differential scanning calorimetry (DSC). The (solid+liquid) equilibria, SLE, of iPBu-1 with different hydrocarbons (n-hexadecane, 1-heptene, 1-heptyne, cyclopentane, cyclohexane, cycloheptane, cyclooctane, benzene and propylbenzene) were studied by a dynamic method. By performing these experiments over a large concentration range, the temperature-mole fraction phase diagrams of the polymer-solvent systems could be constructed. From these diagrams it was found that iPBu-1 had the highest solubility in small-ring cycloalkanes and the lowest in n-hexadecane, 1-heptyne and benzene in the mole fraction range measured. The excess Gibbs energy models were used to describe the nonideal behaviour of the liquid phase and to estimate the solubility of iPBu-1 in the whole mole fraction range. Activity coefficients at infinite dilution of polymer and solvent were determined from the solubility measurements and were predicted by using the UNIFAC FV model and molecular Monte Carlo simulations.
Domańska
Urszula
U
Warsaw University of Technology, Faculty of Chemistry, Physical Chemistry Division, Noakowskiego 3, 00-664 Warsaw, Poland. ula@ch.pw.edu.pl
Kozłowska
Marta Karolina
MK