Phase diagrams of the system tetrahydrofuran/γ-butyrolactone/poly(ether imide) and determination of interaction parameters

Jair Francisco Maggioni*, Suzana Nunes, Alfredo T. Nunes Pires, Andreas Eich, Roland Horst, B. A. Wolf

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

7 Scopus citations

Abstract

The thermodynamic interactions in the ternary mixture tetrahydrofuran/γ-butyrolactone/poly(ether imide) (THF/γ-BL/PEI) are investigated from 30 to 50°C. This is a membrane-forming system with a high He-selectivity. Cloud point measurements show that the two binary polymer solutions THF/PEI and γ-BL/PEI exhibit miscibility gaps which close towards the centre of the ternary phase diagram where the mixtures become homogeneous (cosolvency). Vapour pressures were determined for the subsystem THF/γ-BL, For the theoretical calculations the Gibbs energy of mixing is formulated according to the Flory-Huggins theory and the interaction parameter χTHF/γ-BL calculated from the vapour pressures. The adjustment of theoretical phase diagrams to the experimental data (cloud point curves, tie lines and critical points) gives access to χTHF/PEI and χγ-BL/PEI. For a satisfactory representation of the liquid-liquid demixing, a concentration dependent χTHF/PEI is required, whereas concentration independent values for χTHF/γ-BL and χγ-BL/PEI suffice.

Original languageEnglish (US)
Pages (from-to)5133-5138
Number of pages6
JournalPolymer
Volume39
Issue number21
DOIs
StatePublished - Jan 1 1998

Keywords

  • Flory-Huggins parameter
  • Liquid-liquid demixing
  • Ternary mixture

ASJC Scopus subject areas

  • Organic Chemistry
  • Polymers and Plastics
  • Materials Chemistry

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