TECHNOLOGY FOCUS - POLYMERS - Preferred Material: (2) comprises repeating units of formula (I) and (1) comprises repeating units of formula (II) where the phenyl rings are optionally substituted. (I) has an ion-exchange capacity from at least about 0.5 - 4 meq/g and is halogenated (preferably brominated or chlorinated). (I) further comprises sulfone crosslinkages and antioxidants.Preferred Method: The sulfonating agent comprises at least one of sulfur trioxide, concentrated sulfuric acid and fuming sulfuric acid. The agent has a free sulfur trioxide content of about 0 (about 100% sulfuric acid) - 30 (about 70% sulfuric acid). The PEK polymer solution is maintained from about 10 - 60degreesC. Isolating the sulfonated PEK polymers comprises re-precipitating the sulfonated (2) (3) or blends into water, water saturated with NaCl, methanol or other non-solvent. (M1) and (M2) additionally comprises the following: casting a membrane of (1) and crosslinking (1) in the H+ form by a thermal process. Antioxidant is introduced following isolation of sulfonated (2), (3) or blends or the sulfonated PPSU polymers. (M1) and (M2) additional comprises halogenating (preferably chlorinating or brominating) the aromatic backbone of (2), (3) or blends or (1). The hydrocarbon solvent comprises methylene dichloride. (M2) additionally comprises purifying (1) to remove overly sulfonated or degraded fractions. This purification comprises re-dissolving and re-precipitating the sulfonated PPSU polymer into water, water saturated with NaCl, methanol or other solvent. EXAMPLE - A mixture of dichloromethane (340 ml) and Radel R (RTM; polyphenyl sulfone polymer beads) (50 g) was stirred for 0.25 hours in two separate kettles. The solution were cooled to 0degreesC and a mixture of Sultan B (RTM; sulfur trioxide in CH2Cl2)(10 g) and dichloromethane(120 ml) was introduced in one kettle(100% sulfonation). To the second kettle was added a mixture of Sultan B(15 g) and solutions to both kettle was carried out over a period of 3.5 - 4 hours. After complete addition, the reaction mixture were kept at 0degreesC for a further period of 2.5 hours and quenched by addition of deionized water. The polymers were isolated as white powders, dried and cast on soda lime glass plates. The films were heated at 70degreesC under vacuum for an hour and floated off with deionized water. The mechanical strength of both(100% sulfonated and 150% sulfonated) films allowed creasing while resisting tearing. The ion-exchange capacity(IEC)at 100% sulfonated polymer was 1.39 meq/g while that of 150% sulfonated polymer was 1.58 meq/g.