Penetrability P of polyarylate (PA) films of varying porosities was studied for helium, argon, nitrogen and methanol vapours. The coefficients D and σ have been determined. The PA films produced by pouring solutions on to supports have been found to have a porous structure with closed pores. This conclusion has been based on the finding of much porosity, an independence of P on excess pressure and on 1√M (M is the mol.wt. of the diffusing gas). The transport of the gas through the PA film has been found to be the result of an activated diffusion which has an activation energy of 4–6 kcal/mole; the size of the latter is independent of the porosity. A mechanism of penetration of the gases and vapours through glass-like, polymer films with closed pores is suggested.

M.V. Tsilipotkina

Papers

The mechanism of gas penetration in porous polyarylate films