In order to produce solution diffusion membranes, homogeneous and dense films produced by extrusion of melted material or by molding from synthetic polymers having a melting temperature higher than 140<o>C, a vitreous transition temperature higher than 0<o>C and a permanent stability in the presence of boiling ethanol are irradiated by accelerated electrons and are subjected to a graft curing of radicals with monomers containing functional groups. After said curing, the functional groups of grafted polymers are converted into dissociated salts.
