CHARACTERIZATION OF POLYCARBONATE NUCLEAR TRACK ETCHED MEMBRANES BY MEANS OF THE GAS PERMEATION METHOD

The gas permeation technique has been applied to analyse flat polycarb onate nuclear track-etched membranes (TEMs), with pore size smaller th an 100 nm. The samples analysed were the commercial membranes Nuclepor e and the ones which are being developed at IPEN using the IEA-R1 rese arch reactor (2 MW). A linear trend has been obtained for the flux ver sus transmembrane pressure for various gases, when measured at a const ant temperature of 293 K, indicating a constant permeability for this kind of membranes. Furthermore, the permeability has shown a tendency of increasing when the molecular weight of the gases decreased followi ng the Knudsen model predictions. An estimation of the pore radius for all TEMs were realized using the Knudsen equation and the results obt ained were in good agreement with those determined by the SEM techniqu e. (C) 1998 Elsevier Science B.V. All rights reserved.