Process for the preparation of a membrane (m) containing a sulfonated polyarylenesulfone polymer (sp)

A process for the preparation of a membrane (M) containing a sulfonated polyarylenesulfone polymer (sP) comprising the steps

• i) converting a reaction mixture (RG) comprising
• an aromatic dihalogensulfone component (component (A)) comprising
• at least one sulfonated aromatic dihalogensulfone (component (A1)), and at least one
• non sulfonated aromatic dihalogensulfone (component (A2)),
• at least one aromatic dihydroxy compound (component (B)),
• at least on carbonate compound (component (C)), and
• at least one aprotic polar solvent (component (D)),
• to obtain a product mixture (PG) comprising a sulfonated polyarylenesulfone polymer (sP), the at least one aprotic polar solvent and at least one inorganic halide compound,
• ii) separating the at least one inorganic halide from the product mixture (PG) to obtain a solution (S) comprising the sulfonated polyarylenesulfone polymer (sP) and the at least one aprotic polar solvent,
• iii) separating the at least one aprotic polar solvent from the solution (S) to obtain the membrane (M) containing the sulfonated polyarylenesulfone polymer (sP),
• wherein the sulfonated polyarylenesulfone polymer (sP) in the solution (S) in step ii) remains in dissolved form before step iii) is conducted.