A Mass Spectrometric Method for the Determination of Permeability Coefficients

摘要

A method for the determination of permeability coefficients from mass spectral data has been described in detail. The method has been illustrated by the determination of permeability coefficients for the systems N2-neoprene, O2-neoprene, and CO2-neoprene at room temperature. The value for the permeability coefficient Q for CO2 through neoprene has been shown to be independent of membrane thickness with diaphragms of 0.081 and 0.200 cm thickness (Q=13.1=0.3x10 to the minus eleventh power and 13.3=0.2x10 to the minus eleventh power sq cm/sec torr, respectively). The data presented shows that Q increases with a decrease in the pressure of 1.0 to 0.5 atmosphere across the membrane. For the CO2-neoprene system, the values of Q for pressure differentials of 1.0, 0.75, and 0.50 atmosphere are 13.3=0.02x10 to the minus eleventh power, 16.2=0.2x10 to the minus eleventh power, and 19.2=0.1x10 to the minus eleventh power sq cm/sec torr, respectively. For the same three pressure differentials with N2-neoprene, the values of Q were found to be 2.87=0.04x10, to the minus eleventh power, and 7.00=0.03x10 to the minus eleventh power sq cm/sec torr, respectively. This trend was not checked for the O2neoprene system due to experimental difficulties. The values for Q at a pressure differential of 1 atmosphere agree with previously published values. (Author)