TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The cationic groups are ammonium groups, which are trimethylammoniumalkyl, triethylammoniumalkyl, dimethylethylammoniumalkyl, dimethylisopropylammoniumalkyl, dimethylaminoethyl-dimethylammoniumalkyl and/or alkyldimethylammonium-ethyldimethylammoniumalkyl. The cationic groups are trimethylammoniummethyl groups or ethyldimethylammonium-ethyl-dimethylammoniumalkyl groups. The chloroalkylating agent is bischloromethylether. The ratio of the chloromethylating agent to the polymer is 2:1-8:1, 3:1-8:1, 2:1-6:1, 3:1-6:1, 2:1-5:1, 3:1-5:1, 2:1-4:1 or 3:1-4:1. The quaternizing agent is: a tertiary amine, which is trimethylamine, triethylamine, dimethylethylamine, dimethylisopropylamine or tetramethylethylenediamine; or a diamine, which is tetramethylethylenediamine, tetramethylpropylenediamine or pentamethyldiethylenediamine.    TECHNOLOGY FOCUS - POLYMERS - Preferred Components: The polymer further comprises the residues of one or more optionally substituted phthalate monomers. The residues of the optionally substituted bisphenol A monomer and residues of the optionally substituted phthalate monomer form ethers and/or imides. The molar ratio of cationic groups to residues of bisphenol A monomers is 1:1-2.5:1, 1:1-2:1, 1:1-1.5:1, 1.5:1-2:1 or 1.5:1. (I) further comprises one or more anions, where many anions are hydroxide ions. The polymer is crosslinked with a polyamine, which is a tetramethylalkylenediamine. (I) has a conductivity of 0.002 (preferably 0.007) S/cm or greater in aqueous hydroxide at 20 degrees C or greater, where the concentration of aqueous hydroxide is 0.5 molar or greater. (I) is stable to aqueous hydroxide at a concentration of 2 (preferably 3) molar or greater. (I) is stable to aqueous hydroxide at a concentration of 0.5 molar or greater, preferably 2 molar or greater at 60 degrees C or greater. (I) is stable to aqueous hydroxide at a concentration of 0.5-1.5 (preferably 1-1.5) molar at 60-80 degrees C. The optionally substituted bisphenol A monomers include one or more chloroalkyl groups. The bisphenol A monomers form ethers and/or imides with many phthalate monomers; or a first bisphenol A monomers form ethers with a first phthalate monomers, and a second bisphenol A monomers form imides with a second phthalate monomers. Preferred Process: The process further comprises: the step of reacting the chloroalkylated polymer with a quaternizing agent to form a quaternized polymer; alkylating the quaternized polymer with a 1-4C alkylating agent; and reacting the quaternized polymer with hydroxide ion. EXAMPLE - A mixture of 4,4'-(4,4'-isopropylidene-diphenyl-1,1'-diyldioxy)dianiline (12.3 g), 4,4'-(4,4'-isopropylidene-diphenoxy)bis(phthalic anhydride) (15.6 g), pyridine (12 ml), dimethyl formamide (DMF) (60 ml), was heated with stirring at 150 degrees C for 3 hours. The temperature was increased to 190-200 degrees C and kept for another 2 hours to give polyimide, after removal of water. To the obtained polyimide (2 g) in chloroform, zinc chloride (0.6 g) and chloromethyl methyl ether (1 ml) were added. The reaction was kept at 60 degrees C for 3 hours before purification. The polymer was precipitated with methanol and dried to give chloromethylated polymer. The obtained chloromethylated polymer was dissolved in DMF and heated at 150 degrees C in a glass container for 5 hours, followed by heating at 200 degrees C for another 2 hours to give membrane.