Gas-Sorption Properties of 6FDA-Durene/1,4-Phenylenediamine (pPDA) and 6FDA-Durene/1,3-Phenylenediamine (mPDA) Copolyimides

Si Xue Cheng, Tai Shung Chung*, Rong Wang, Rohit H. Vora

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

37 Scopus citations


We investigated the sorption isotherms of O2, N2, CH4, and CO2 gases in 6FDA-durene, 6FDA-1,4-phenylenediamine (6FDA-pPDA), and 6FDA-1,3-phenylenediamine (6FDA-mPDA) homopolymers and 6FDA-du-rene/pPDA and 6FDA-durene/mPDA copolyimides. The solubilities decrease in the order of the inherent condensabilities of the penetrant gases, namely, CO2, CH4, O2, and N2. The chemical structures of the polymer, as well as the chain packing, determine the sorption properties of these homopolymers and copolymers. The FDA-durene homopolymer has the highest solubility for all gases because of its high specific free volume and fractional free volume. The solubilities of the copolymers increase with an increasing 6FDA-durene content, while the solubility selectivities of the copolymers only vary slightly. The values of KD (Henry's law constant) and CH′ (Langmuir site capacity) of these copolyimides decrease with a decreasing 6FDA-durene content. To our surprise, contradictory to the previous known fact that the mete-connected materials tend to have denser molecular packing than that of the para-linked materials for homopolymers, the 6FDA-durene/mPDA 80/20 copolymer has higher gas solubilities than those of the 6FDA-durene/ pPDA 80/20 copolymer. The random moiety sequence within the copolymer may be the main cause for the abnormal phenomenon.

Original languageEnglish (US)
Pages (from-to)2187-2193
Number of pages7
JournalJournal of Applied Polymer Science
Issue number8
StatePublished - Nov 21 2003
Externally publishedYes


  • Copolymerization
  • Gas permeation
  • Polyimides

ASJC Scopus subject areas

  • Chemistry(all)
  • Surfaces, Coatings and Films
  • Polymers and Plastics
  • Materials Chemistry


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