Gas transport through polyethylene membranes

Transport rates were measured by monitoring the pressure decay between two reservoirs connected by a polyethylene membrane. The diffusion equation was integrated to obtain a relation between the pressure difference across the reservoirs and the time, with solubility, expressed by Henry's law constant H , and the diffusivity D as parameters. A procedure was developed whereby both H and D are evaluated from a single set of Δ p vs. t measurements. For argon in low‐density polyethylene, H and D at 323 K were 35[kg·mo]/(m 3 of gas)/[kg·mol/(m 3 of polymer)] and 2.1 × 10 −10 m 2 /s, respectively. For the high‐density sample these values were 38.7 and 1.11 × 10 −10 at 298.1 K.