| abstract |
Process for the preparation of a membrane by extrusion of a thermoplastic polymer having alkaline ionic groups, which consists in preparing a mixture consisting of a polymer having alkaline ionic groups of formula -AP- (M +) p in which A represents the part anionic of the ionic group, p represents the valence of the anionic part and M represents an alkali metal and by at least one plasticizer, extruding the mixture obtained to form a film, then washing the film obtained in aqueous medium to remove said (s) plasticizer (s), characterized in that the plasticizer (s) has a boiling temperature higher than the maximum extrusion temperature of the polymer, is (are) stable with respect to the ionic groups of the polymer, it is (are) soluble in water or in solvents miscible with water, and is selected from: i) - the oligoethers which optionally have CH3, OH or NH2 terminal groups; - R3-SO2-R4 sulfones in which R3 and R4 independently represent each other an alkyl having between 1 and 3 carbon atoms, or an aryl comprising one or more aromatic nuclei, condensed or not, or R3 and R4 form with each other a biradical to form a cycle with the SO2 group providing a sulfolane; - the carboxylic amides of formula HCONR6R7 in which R6 and R7 represent alkyl groups having between 1 and 4 carbon atoms; - sulfonic amides such as tetraalkylsulfamides; ii) plasticizers presenting protic functional groups selected from among the carboxylic amide functional groups having 1 or 2 hydrogen atoms in the nitrogen atom, and sulfonic amide functional groups having 1 or 2 hydrogen atoms in the nitrogen atom , the functional groups alcohol, thiol, phenol, primary amine and secondary amine, said plasticizers being selected from: - the alkanols having at least 2 carbon atoms, the polyols obtained from alkanes by replacing at least two hydrogen atoms per an OH group and the compounds having ether groups; - monoamine, diamine or triamine oligomers and in which the nitrogen atom has between 1 and 3 oligo (oxyethylene) groups; - the sulfamide H2N-SO2-NH2, the sulfamides R8-SO2NH2 in which R8 is an alkyl group having between 1 and 5 carbon atoms, or an aryl group comprising one or more aromatic nuclei, condensed or not; - primary or secondary amides. |