Organic vapor sorption and transport in a thermotropic liquid crystalline polyester

N. R. Miranda, J. T. Willits, B. D. Freeman, H. B. Hopfenberg

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The sorption and transport properties of small molecules in a glassy liquid crystalline random copolyester, composed of 73 mol% p-hydroxybenzoic acid and 27 mol% 6-hydroxy-2-naphthoic acid (HBA/HNA), are reported. Acetone and methylene chloride sorption levels were extraordinarily low in HBA/HNA, and isotherms were convex to the activity axis, suggesting plasticization of the region of polymer accommodating penetrant sorption. These composite observations suggested that penetrant solubility may be limited to disclination regions between liquid crystalline domains. The gravimetric sorption kinetics were described by the Fickian model at low penetrant activities but exhibited non-Fickian protracted drifts at high penetrant activities, despite low overall penetrant concentrations. The values of acetone and methylene chloride diffusion coefficients in HBA/HNA were comparable to diffusion coefficient values of these penetrants in conventional glassy polymers.

Original languageEnglish
Pages (from-to)67-83
Number of pages17
JournalJournal of Membrane Science
Issue number1
Publication statusPublished - 19 Sep 1994
Externally publishedYes


  • barrier membranes
  • gas and vapor permeation
  • liquid crystalline polymers
  • solubility and partitioning

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