主权项 |
1. A proton-conducting polymer membrane based on polyazole-copolymers obtainable by a process comprising the steps of
A) mixing:
(i) at least one aromatic tetraamino compounds and(ii) at least two different aromatic carboxylic acids or esters thereof which contain at least two acid groups per carboxylic acid monomer, in polyphosphoric acid to form a solution and/or dispersion B) heating the mixture from step A) and polymerizing until an inherent viscosity of at least 0.8 dL/g, is obtained for the copolymer being formed, C) applying a membrane layer using the mixture according to step B) on a carrier or on an electrode, D) optionally heating the membrane on the carrier or electrode obtained from step C), E) treating the membrane formed in the presence of water and/or moisture, F) removal of the membrane from the carrier, wherein G) the total amount of all aromatic tetraamino compounds and all aromatic carboxylic acids or esters thereof in step A) is at least 5% by weight and up to about 25% by weight, and said total content includes any acids and water being present, said total content excluding however any optional additives, H) one of the at least two different aromatic carboxylic acids or esters thereof which contain at least two acid groups per carboxylic acid monomer (first aromatic carboxylic acid) is pyridine-2,5-dicarboxylic acid or pyridine-3,5-dicarboxylic acid, and I) one of the at least two different aromatic carboxylic acids or esters thereof which contain at least two acid groups per carboxylic acid monomer (second aromatic carboxylic acid) is selected from terephthalic acid, isophthalic acid, mono-hydroxy-benzene-1,4-dicarboxylic acid, mono-hydroxy-benzene-1,3-dicarboxylic acid, mono-hydroxy-benzene-1,2-dicarboxylic acid, di-hydroxy-benzene-1,4-dicarboxylic acid, di-hydroxy-benzene-1,3-dicarboxylic acid, or di-hydroxy-benzene-1,2-dicarboxylic acid, J) the molar fraction of the first aromatic carboxylic acid is between 0.1 to 0.9 and K) the molar fraction of the second aromatic carboxylic acid is chosen so that the sum of the molar fraction of the first aromatic carboxylic acid and the molar fraction of the second aromatic carboxylic acid is 1.0. |