Mass spectrometer based gas permeation apparatus
A newly constructed instrument to measure diffusion and permeation rates in polymeric materials is described. This instrument utilizes a quadrupole mass spectrometer as a sensitive flow meter to detect the flux of gas through a polymer sheet that is subjected to a pressure gradient. The permeation coefficient is obtained from the steady state flux and the diffusion coefficient from the kinetics of reaching the steady state in a sheet that is initially devoid of permeant. The diffusion coefficient depends solely on the time development of the mass spectrometer signal and calibration is not required. To obtain the actual flux, however, the mass spectrometer output is calibrated by effusing a known quantity of the test gas into the spectrometer through an orifice. Enclosure of the sample cell in an oven permits the temperature dependences of the diffusion parameters to be derived. The instrument was tested by measuring the diffusion behavior of helium in ethylenepropylene rubber as a function of temperature and the results agree well with literature values.
- Research Organization:
- Sandia National Labs., Albuquerque, NM (USA)
- DOE Contract Number:
- AC04-76DP00789
- OSTI ID:
- 5756735
- Report Number(s):
- SAND-85-0402; ON: DE85011176
- Country of Publication:
- United States
- Language:
- English
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