Patent ID: 7235320

Claim:
A proton-conducting polymer membrane based on polyazoles which is obtained by a process comprising the steps A) Reacting one or more aromatic tetraamino compounds with one or more aromatic carboxylic acids or esters thereof which contain at least two acid groups per carboxylic acid monomer, or of one or more aromatic and/or heteroaromatic diaminocarboxylic acids in the melt at temperatures of up to 350° C., B) Dissolution of the solid prepolymer obtained as described in step A) in polyphosphoric acid, C) Heating of the solution obtained as described in step B) to temperatures of up to 300° C., under inert gas to form the dissolved polyazole polymer, D) Formulating a membrane on a support using the solution of the polyazole polymer from step C), and E) Treating the membrane formed in step D) until it is self-supporting.