Patent ID: 8138231

Claim:
A polymer having an oxocarbon group represented by the following formula (1) wherein X 1 and X 2 independently represent —O—, —S—, or —NR—, and Z represents —CO—, —C(S)—, —C(NR′)—, alkylene group which may have substitution groups, or arylene group which may have substitution groups, wherein R and R′ of NR and NR′ independently represent hydrogen atom, alkyl group with carbon number of 1 to 6 which may have substitution groups, or aryl group with carbon number of 6 to 10 which may have substitution groups; n is a repeating number and represents the number of n=0 to 2, n Z-groups may be same or different from each other; and B represents hydrogen atom or a monovalent metal atom, wherein ion exchange capacity of the polymer is bigger than 3.0 meq/g, and the main chain structure of the polymer is selected from the group consisting of vinyl polymers, polyoxyalkylenes, polysiloxanes, polyesters, polyimides, polyamides, polybenzoxazoles, polybenzimidazoles, polyaryleneethers, polyarylenes, polyarylenesulfides, polyetherketones, polyethersulfones, and polyphosphazenes, and copolymers thereof.