Phase boundary calculations for solutions of a polydisperse polymer

Citation
N. Koak et Ra. Heidemann, Phase boundary calculations for solutions of a polydisperse polymer, AICHE J, 47(5), 2001, pp. 1219-1225
Citations number
19
Categorie Soggetti
Chemical Engineering
Journal title
AICHE JOURNAL
ISSN journal
00011541 → ACNP
Volume
47
Issue
5
Year of publication
2001
Pages
1219 - 1225
Database
ISI
SICI code
0001-1541(200105)47:5<1219:PBCFSO>2.0.ZU;2-E
Abstract
A technique is described for performing phase boundary calculations (cloud- point calculations) for solutions of a polydisperse polymer in a solvent co mponent. The polymer is characterized as a potentially large number of indi vidual components. The technique employs the Newton method for solving the nonlinear equilibrium equations. The independent variables in the equations are logarithms of the equilibrium ratios, temperature and pressure, and th e mass ratio of polymer to solvent. A number of cloud-point curves were cal culated using the Sanchez-Lacombe equation as the thermodynamic model. The calculations were compared with experimental data for polyethylene (M-W = 1 77,000 and M-N = 8,000) with n-hexane and polyethylene (M-W = 99,000 and M- N = 56,000) with ethylene. As expected, the disperse nature of the polymer significantly affected the calculated phase behavior of the polymer-solvent mixtures. Complicating features in the calculations are discussed.