Structure of structurally inhomogeneous sulphocationic membranes and their gas permeability

Abstract The effect of the structure of sulphocationic membranes in the H + form, prepared by sulphonation of LDPE films with PS grafts by means of sulphuric and chlorosulphonic acids, on their permeability to carbon dioxide was studied. In the course of sulphonation by means of sulphuric acid, the membrane is transformed from an originally single-layer hydrophobic one into a three-layer and ultimately at full sulphonation into a single-layer hydrophilic one, and this is reflected in the character of the permeability changes of these membranes. The dependence of the permeability on the content of grafted PS determining the maximum concentration of sulphoacid groups is of S-shaped character and is well described by means of the percolation theory. The determining role of the continuous aqueous phase, formed from the sulphoacid group hydrate shells, for carbon dioxide transport is demonstrated.