Moreover, the permeation properties of the substrates
were evaluated by a nitrogen permeation test carried out at
room temperature and different transmembrane pressures.
Prior to the test, the samples with one end sealed were glued
onto a stainless steel holder using epoxy-resin (Araldite®),
which was then connected to the permeation apparatus
shown in Fig. 1.
The pressure of the feed gas (N2) was adjusted
using a pressure regulator (OMEGA, PRG101-120) and monitored
using a pressure gauge with a resolution of 0.1 psi
(OMEGA, DPG1000B-10G).
The flux of the N2 permeated through the substrate was measured at transmembrane
pressures between 20 and 100 kPa using bubble flow meters.