Free-volume studies in polyurethane membranes by positron annihilation spectroscopy

M. F. Ferreira Marques, C. Lopes Gil, P. M. Gordo, Zs Kajcsos, A. P. De Lima, D. P. Queiroz, M. N. De Pinho

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The free-volume parameters in various urethane/urea membranes obtained by varying the ratio of the structural constituents, polypropylene oxide and polybutadiene, were studied by positron lifetime and Doppler broadening measurements. On bi-soft segment membranes, a correlation was found between the composition of membranes, the normalized free volume, the radii of the holes and gas permeability. However, the correlation is not clear when PU data are also considered, indicating that other features must also play an important role in the permeation mechanism.

Original languageEnglish
Pages (from-to)573-576
Number of pages4
JournalRadiation Physics and Chemistry
Issue number3-4
Publication statusPublished - Jan 1 2003



  • Free volume
  • Permeability
  • Phase separation
  • Pore size
  • Positronium
  • Urethane/urea polymers

ASJC Scopus subject areas

  • Radiation

Cite this

Ferreira Marques, M. F., Lopes Gil, C., Gordo, P. M., Kajcsos, Z., De Lima, A. P., Queiroz, D. P., & De Pinho, M. N. (2003). Free-volume studies in polyurethane membranes by positron annihilation spectroscopy. Radiation Physics and Chemistry, 68(3-4), 573-576.