Techniques for the experimental determination of liquid permeation data, with particular reference to the n‐hexane/polythene system

Permeation rates of n‐hexane through polythene membranes have been determined as a function of temperature and pressure. The influence of membrane annealing and of the particular experimental technique adopted was studied. Concentration differences and diffusion coefficients were estimated from measurements of the time lag before a steady permeation rate could be achieved. It was shown that both random and systematic errors were so large that exact estimates of the diffusion coefficient were not possible. It was therefore necessary to use desorption data in conjunction with measurements of the permeation rate to arrive at values for the diffusion coefficient.