Permeation of Moisture and Oxygen Through Polymeric O-Rings

摘要

The permeation coefficients ofH_2O and O_2 through polymeric O-rings were obtained in this study. Increases of trace level impurities in an ultra-high purity nitrogen purge gas due to the permeation processes were measured using an atmospheric pressure ioniza-tion mass spectrometer (APIMS). In this paper, the experimental results of nine different O-ring samples (Kalrez, Chemraz, Teflon, Vespel, Viton) are reported. The Kalrez "wet" O-ring showed the lowest moisture permeation coefficient of l.5x10~(-10) [cm~3 gas(STP) · cm polymer]/[cm~2 polymer · sec · torr] and Vespel displayed the lowest oxygen permeation coefficient of 0.01x10~(-10) [cm~3 gas(STP) · cm polymer]/[cm~ polymer · sec · torr] at room temperature. In addition, permeation coefficients at 50℃ and 75℃ are presented. The activation energies varied from about 18 to 51 kJ/mole/ °K for both H_2O and O_2.