Permeation of dimethyl sulfoxide through polyethylene membraness

Permeability and diffusion coefficients for dimethyl sulfoxide (DMSO) in polyethylene have been measured by the “time‐lag” technique and found to be affected by the adsorption of DMSO vapor in the low‐pressure side of the apparatus. An analytical method is described for correcting the apparent permeability coefficients for such adsorption effects. “True” permeability coefficients for DMSO in polyethylene, expressed in units of cm3(STP) – cm/(sec‐cm2‐cmHg), vary from 0.92 X 10‐7 at 30°C to 1.7 X 10‐7 at 45°C, and their dependence on relative DMSO pressure appears to be small. The energy of activation for the permeation process is 7.1 kcal/mole. The described correction method is also applicable to the permeation of water vapor through polyethylene and poly‐(phenylene oxide). The apparent diffusion coefficients could not be corrected by this method. The solubility of DMSO in polyethylene was measured with a Bakr‐McBain balance and found to be very small; solubility coefficients are less than 0.8 cm3(STP) DMSO/(cm3 polymer‐cmHg). It is concluded that the transport and solution behavior of DMSO in polyethylene is more similar to that of water vapor than to the corresponding behavior of organic vapors.