Development of asymmetric 6FDA-2,6DAT hollow fiber membranes for CO2/CH4 separation: Part 2. Suppression of plasticization

Tai-Shung Chung*, Jizhong Ren, Rong Wang, Dongfei Li, Ye Liu, K. P. Pramoda, Chun Cao, Wei Wei Loh

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

53 Scopus citations


We have studied the CO2-induced plasticization phenomenon of asymmetric poly(2,6-toluene-2,2-bis(3,4-dicarboxyphenyl) hexafluoropropane diimide) (6FDA-2,6 DAT) hollow fiber membranes for CO2/CH4 applications. Several processing and thermal approaches have been investigated to study their effectiveness to enhance anti-plasticization characteristics. Experimental results indicate that hollow fiber membranes spun at different shear rates and take-up rates cannot effectively suppress the CO2 induced plasticization. Thermally treated 6FDA-2,6 DAT hollow fiber membranes show significant reduction in CO2-induced plasticization. Wide-angle XRD spectra reveal no visible change in d-space after thermal treatment, while solubility data imply no cross-links occurred. Scanning electron microscopy (SEM) pictures illustrate heat treatment results in more compact selective-skin layer and substructure, thus strengthening the anti-plasticization characteristics of hollow fibers. By considering the degree of plasticization, dense-layer thickness, and heat treatment temperature, an optimal temperature of 250°C (for 5min) is identified for the heat treatment of 6FDA-2,6 DAT hollow fiber membranes. NMR spectra suggest the cause of forming a highly densified skin after heat treatment is mainly due to chain relaxation and enhanced nodule interaction at elevated temperatures.

Original languageEnglish (US)
Pages (from-to)57-69
Number of pages13
JournalJournal of Membrane Science
Issue number1
StatePublished - Mar 15 2003


  • 6FDA-2,6 DAT polyimide
  • CO-induced plasticization
  • CO/CH separation
  • Heat treatment
  • Hollow fiber membrane
  • Suppression of plasticization

ASJC Scopus subject areas

  • Filtration and Separation
  • Polymers and Plastics


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