Determination of mixed gas permeability of high free volume polymers using direct mass spectrometric analysis of the gas compositions

摘要

In the present work the mixed gas permeability of polymeric membranes is determined with an instrument (see Figure 1) which uses direct mass spectrometric analysis of the gas composition without the prior gas chromatographic separation. Transport properties of dense polymeric membranes either in flat film configuration or in the form of hollow fibres are measured. The instrument consists of a differential permeameter with a sweep gas (helium or argon) on the permeate side, adjustable pressure on the feed side of the measured membrane and adjustable stage cut. The detector is a mass spectrometer with an inert quartz column, which analyzes complex mixtures by appropriate deconvolution of overlapping signals. This offers the advantage of potentially much faster measurements than in the case of for instance gas chromatographic analysis of the gas composition and may open the possibility to study transient behaviour in gas mixture permeation. The measurements are conducted at 25°C with the possibility to change the temperature.