DE10235357A1 - Proton conducting polymer membrane, useful for the production of fuel cells, is prepared by mixing an aromatic tetra-amino compound with an aromatic carboxylic acid in vinyl containing phosphoric and sulfonic acid - Google Patents

Abstract

A proton conducting polymer membrane comprising sulfonic acid group containing polymers is prepared by mixing an aromatic tetra-amino compound with an aromatic carboxylic acid in vinyl containing phosphoric acid and vinyl containing sulfonic acid to form a solution or dispersion and heating under an inert gas to form a polyazole polymer, applying a layer of the mixture onto a support and polymerization of the vinyl containing sulfonic acid. A proton conducting polymer membrane comprising phosphoric acid and sulfonic acid group containing polymers is prepared by: (a) mixing at least one aromatic tetra-amino compound with at least one aromatic carboxylic acid or its ester that has at least 2 acid groups per carboxylic acid monomer or mixing at least one (hetero)aromatic diaminocarboxylic acid, in vinyl containing phosphoric acid and vinyl containing sulfonic acid to form a solution or dispersion; (b) heating the resulting solution or dispersion under an inert gas up to 350 degreesC to form a polyazole polymer; (c) applying a layer of the mixture from step (A) or (B) onto a support and; (d) polymerization of the vinyl containing sulfonic acid in the flat sheet from step (C). Independent claims are included for: (1) an electrode having a proton conducting polymer coating of the membrane (I) prepared by application of the mixture (A) onto an electrode, heating to 350(280) degreesC under inert gas to form a polyazole polymer and polymerization of the vinyl containing phosphoric acid and vinyl containing sulfonic acid; (2) a membrane-electrode unit (II) containing at least one electrode and a membrane (I) and; (3) a fuel cell containing at least one membrane-electrode unit (II).

Description

Proton-conducting polymer membrane comprising phosphonic and sulfonic acid groups containing polymers and their use in fuel cells.

The present invention relates to a proton-conducting polymer electrolyte membrane comprising phosphonic acid and sulfonic acid containing polymers, which due to their excellent chemical and thermal properties varied can be used and in particular as a polymer electrolyte membrane (PEM) in so-called PEM fuel cells.

A fuel cell usually contains an electrolyte and two electrodes separated by the electrolyte. In the case of a fuel cell, one of the two electrodes is switched on Fuel, such as hydrogen gas or a methanol-water mixture, and the other electrode an oxidizing agent such as oxygen gas or air and thereby chemical energy directly from fuel oxidation converted into electrical energy. In the oxidation reaction Protons and electrons are formed.

The electrolyte is for hydrogen ions, d. H. Protons, but not for reactive fuels like hydrogen gas or methanol and that Permeable to oxygen gas.

A fuel cell points in the Usually several single cells so-called MEΈ's (membrane electrode unit) on, each one an electrolyte and two by the electrolyte separate electrodes included.

Coming as the electrolyte for the fuel cell Solids such as polymer electrolyte membranes or liquids like phosphoric acid to use. Most recently Polymer electrolyte membranes have time as electrolytes for fuel cells Attracted attention. In principle you can choose between 2 categories differ from polymer membranes.

The first category includes cation exchange membranes consisting of a polymer structure which covalently bound acid groups, preferably sulfonic acid groups contains. The sulfonic acid group turns into an anion with release of a hydrogen ion and therefore conducts protons. The mobility of the proton and thus the proton conductivity is directly linked to the water content. Due to the very good miscibility of methanol and water have such cation exchange membranes a high methanol permeability on and are therefore for Applications in a direct methanol fuel cell unsuitable. Dries the membrane, e.g. B. as a result of high temperature, so takes the conductivity the membrane and consequently the performance of the fuel cell dramatically from. The operating temperatures of fuel cells containing such Cation exchange membranes is thus at the boiling point of the Water limited. The humidification of the fuels is a major technical challenge for the Use of polymer electrolyte membrane fuel cells (PEMBZ), where conventional, sulfonated membranes such. B. Nafion used become.

So you use as materials for polymer electrolyte membranes for example perfluorosulfonic acid polymers. The perfluorosulfonic acid polymer (such as Nafion) generally has a perfluorocarbon skeleton, such as a copolymer of tetrafluoroethylene and trifluorovinyl, and one attached side chain with a sulfonic acid group, like a side chain with a sulfonic acid group attached to a perfluoroalkylene group.

With the cation exchange membranes it is preferably organic polymers with covalent bound acid groups, especially sulfonic acid. Methods for sulfonating polymers are described in F. Kucera et. al. Polymer Engineering and Science 1988, Vol. 38, No 5, 783-792.

The most important types of cation exchange membranes are listed below which have gained commercial importance for use in fuel cells:
The most important representative is the perfluorosulfonic acid polymer Nafion ^® ( US 3692569 ).

This polymer can be used as in US 4453991 described in solution and then used as an ionomer. Cation exchange membranes are also obtained by filling a porous support material with such an ionomer. Expanded Teflon is preferred as the carrier material ( US 5635041 ).

Another perfluorinated cation exchange membrane can be as in US 5422411 described by copolymerization from trifluorostyrene and sulfonyl-modified trifuorostyrene. Composite membranes consisting of a porous carrier material, in particular expanded Teflon, filled with ionomers consisting of such sulfonyl-modified trifluorostyrene copolymers are in US 5834523 described.

US 6110616 describes copolymers of butadiene and styrene and their subsequent sulfonation for the production of cation exchange membranes for fuel cells.

Another class of partially fluorinated cation exchange membranes can be caused by radiation grafting and subsequent sulfonation. As in EP 667983 or DE 198 44 645 described on a previously irradiated polymer film, a grafting reaction is preferably carried out with styrene. The sulfonation of the side chains then takes place in a subsequent sulfonation reaction. Crosslinking can also be carried out at the same time as the grafting, and the mechanical properties can thus be changed.

In addition to the above membranes, another class of non-fluorinated membranes has been developed by sulfonation of high-temperature stable thermoplastics. Membranes made from sulfonated polyether ketones ( DE 42 19 077 . EP 96/01177 ), sulfonated polysulfone (J. Membr. Sci. 83 (1993) p.211) or sulfonated polyphenylene sulfide ( DE 195 27 435 ) known.

Ionomers made from sulfonated polyether ketones are in WO 00/15691 described.

Furthermore, acid-base blend membranes are known, which as in DE 198 17 374 or WO 01/18894 described by mixtures of sulfonated polymers and basic polymers.

To further improve the membrane properties, a cation exchange membrane known from the prior art can be mixed with a high-temperature stable polymer. The production and properties of cation exchange membranes consisting of blends of sulfonated PEK and a) polysulfones ( DE 44 22 158 ), b) aromatic polyamides (42445264) or c) polybenzimidazole ( DE 198 51 498 ) are described.

Disadvantage of all of these cation exchange membranes the fact that the membrane needs to be moistened is the operating temperature to 100 ° C limited and the membranes have a high methanol permeability. Cause of this disadvantage is the conductivity mechanism the membrane in which the transport of the protons to the transport of the water molecule is coupled. This is known as the "vehicle mechanism" (K.-D. Kreuer, Chem. Mater. 1996, 8, 610-641).

As a second category, polymer electrolyte membranes with complexes of basic polymers and strong acids have been developed. So describes WO 96/13872 and the corresponding one U.S. Patent 5,525,436 a process for producing a proton conductive polymer electrolyte membrane in which a basic polymer such as polybenzimidazole is treated with a strong acid such as phosphoric acid, sulfuric acid, etc.

In J. Electrochem. Soc., Volume 142, No. 7, 1995, pp. L121-L123 describes the doping of a polybenzimidazole in phosphoric acid.

In those known in the prior art basic polymer membranes is used to achieve the required Proton conductivity - used mineral acid (mostly concentrated phosphoric acid) usually added after the shaping of the polyazole film. The polymer serves as a carrier for the Electrolytes consisting of the highly concentrated phosphoric acid. The Polymer membrane met in doing so, it must have other essential functions high mechanical stability have and as a separator for the two fuels mentioned above serve.

Significant advantages of such phosphoric acid doped membrane is the fact that a fuel cell, both such a polymer electrolyte membrane is used at temperatures above 100 ° C operated without the otherwise necessary humidification of the fuels can be. This is due to the property of phosphoric acid Protons with no additional To be able to transport water using the so-called Grotthus mechanism (K.-D. Kreuer, Chem. Mater. 1996, 8, 610-641).

Due to the possibility of operation at Temperatures above 100 ° C there are further advantages for the fuel cell system. On the one hand, the sensitivity of the Pt catalyst opposite Gas pollution, especially CO, is greatly reduced. CO is created as a by-product in the reforming of the hydrogen-rich gas from carbon-containing compounds, such as. B. natural gas, methanol or gasoline or as an intermediate in direct oxidation of methanol. Typically, the CO content of the fuel smaller at temperatures <100 ° C than 100 ppm. At temperatures in the range of 150-200 ° C, however 10,000 ppm CO or more can also be tolerated (N.J. Bjerrum et. al. Journal of Applied Electrochemistry, 2001, 31, 773-779). This leads to significant simplifications of the upstream reform process and thus to reduce costs of the entire fuel cell system.

A major advantage of fuel cells is the fact that the energy of the fuel is converted directly into electrical energy and heat during the electrochemical reaction. Water forms as a reaction product on the cathode. Heat is therefore a by-product of the electrochemical reaction. For applications in which only the electricity is used to drive electric motors, such as B. for automotive applications, or as a versatile replacement for battery systems, the heat must be dissipated to avoid overheating of the system. Additional, energy-consuming devices are then required for cooling, which further reduce the overall electrical efficiency of the fuel cell. For stationary applications such as central or decentralized generation of electricity and heat, the heat can be efficiently used by existing technologies such as. B. Use heat exchanger. High temperatures are aimed at to increase efficiency. The operating temperature is above 100 ° C and is If the temperature difference between the ambient temperature and the operating temperature is large, it becomes possible to cool the fuel cell system more efficiently or to use small cooling surfaces and to dispense with additional devices compared to fuel cells that have to be operated at below 100 ° C due to the membrane humidification.

In addition to these advantages, a such a fuel cell system also has disadvantages. So is the shelf life of phosphoric acid doped membranes relatively limited. This is the lifespan in particular by operating the fuel cell below 100 ° C, for example at 80 ° C significantly reduced. In this context, however, it should be noted that that when the cells are started and shut down, the fuel cell at them Temperatures must be operated.

Furthermore, the manufacture of phosphoric acid doped membranes relatively expensive, since usually a prepolymer is formed first, which subsequently with the help of a solvent is poured into a film. After the film has dried in a last step doped with an acid.

In addition, the relatively low mechanical stability of a polyazole film doped with phosphoric acid is a problem. So the membrane can be affected by the pressure caused by the gas that serves as fuel and flows into the fuel cell is generated, damaged if the mechanical stability is too low.

Furthermore, the performance, for example conductivity relatively limited by known membranes.

Furthermore, the known ones doped with phosphoric acid Membranes not in the so-called direct methanol fuel cell (DMBZ) can be used. However, such cells are special Interest because a methanol-water mixture is used as fuel. If a known membrane based on phosphoric acid is used, the fuel cell fails after a very short time.

The present invention lies hence the task of creating a novel polymer electrolyte membrane to provide, which solves the tasks outlined above. In particular the operating temperature should be <0 ° C up to 200 ° C can be expanded without significantly reducing the life of the fuel cell would be.

Furthermore, a polymer electrolyte membrane to disposal are used in many different fuel cells can be. The membrane is said to be particularly suitable for fuel cells, the pure hydrogen as well as numerous carbon-containing fuels especially natural gas, petrol, methanol and biomass as an energy source use. In particular, the membrane is said to be in a hydrogen fuel cell and be used in a direct methanol fuel cell (DMBZ) can.

A membrane according to the invention is also intended economical and can be easily manufactured. About that Furthermore, it was an object of the present invention to polymer electrolyte membranes to create a high performance, especially a high conductivity over a show wide temperature range. The conductivity, especially at high temperatures without additional humidification be achieved.

Furthermore, a polymer electrolyte membrane be created that have high mechanical stability, for example a high modulus of elasticity, high tensile strength and high fracture toughness having.

It was also a task the present invention to provide a membrane that is also in Operation a low permeability against a wide variety of fuels, such as hydrogen or have methanol.

These tasks are solved by a proton-conducting polymer membrane comprising phosphonic acid and sulfonic acid containing polymers with all the features of claim 1. Furthermore, offers an electrode with a proton-conducting polymer coating Based on polyazoles with all the features of claim 16 a solution of underlying task.

A membrane according to the invention shows about a big Temperature range high conductivity, even without a additional Humidification is achieved. Furthermore, a fuel cell, that with a membrane according to the invention is equipped, even at low temperatures, for example at 80 ° C operated without reducing the life of the fuel cell is greatly reduced.

A polymer electrolyte membrane according to the invention has a very low methanol permeability and is particularly suitable for the Use in a DMBZ. This means permanent operation of a fuel cell with a variety of fuels such as hydrogen, natural gas, gasoline, Methanol or biomass possible.

Furthermore, a membrane according to the invention simple and inexpensive getting produced. So can in particular on large quantities of expensive and harmful to health solvents how dimethylacetamide can be dispensed with.

In addition, membranes of the present invention show high mechanical stability, ins special high modulus of elasticity, high tensile strength and high fracture toughness. Furthermore, these membranes have a surprisingly long service life.

• A) Mischen von einem oder mehreren aromatischen Tetra-Amino-Verbindungen mit einer oder mehreren aromatischen Carbonsäuren bzw. deren Estern, die mindestens zwei Säuregruppen pro Carbonsäure-Monomer enthalten, oder Mischen von einer oder mehreren aromatische und/oder heteroaromatischen Diaminocarbonsäuren, in einer Mischung enthaltend vinylhaltige Phosphonsäure und vinylhaltige Sulfonsäure, unter Ausbildung einer Lösung und/oder Dispersion,
• B) Erwärmen der Lösung und/oder Dispersion erhältlich gemäß Schritt A) unter Inertgas auf Temperaturen von bis zu 350°C, vorzugsweise bis zu 280°C unter Ausbildung von Polyazol-Polymeren,
• C) Aufbringen einer Schicht unter Verwendung der Mischung gemäß Schritt A) und/oder B) auf einem Träger,
• D) Polymerisation der in dem flächigen Gebilde erhältlich gemäß Schritt C) vorhandenen vinylhaltigen Phosphonsäure und vinylhaltigen Sulfonsäure.

The present invention relates to a proton-conducting polymer membrane comprising polymers containing phosphonic acid and sulfonic acid groups, obtainable by a process comprising the steps

• A) Mixing one or more aromatic tetra-amino compounds with one or more aromatic carboxylic acids or their esters, which contain at least two acid groups per carboxylic acid monomer, or mixing one or more aromatic and / or heteroaromatic diaminocarboxylic acids, in a mixture containing vinyl-containing phosphonic acid and vinyl-containing sulfonic acid, with the formation of a solution and / or dispersion,
• B) heating the solution and / or dispersion obtainable according to step A) under inert gas to temperatures of up to 350 ° C., preferably up to 280 ° C., with the formation of polyazole polymers,
• C) applying a layer using the mixture according to step A) and / or B) on a support,
• D) Polymerization of the vinyl-containing phosphonic acid and vinyl-containing sulfonic acid present in the sheet-like structure obtainable in step C).

worin
R eine Bindung, eine C1-C15-Alkylgruppe, C1–C15-Alkoxygruppe, Ethylenoxygruppe oder C5–C20-Aryl oder Heteroarylgruppe bedeutet, wobei die vorstehenden Reste ihrerseits mit Halogen, -OH, COOZ, -CN, NZ₂ substituiert sein können,
Z unabhängig voneinander Wasserstoff, C1–C15-Alkylgruppe, C1-C15-Alkoxygruppe, Ethylenoxygruppe oder C5–C20-Aryl oder Heteroarylgruppe– bedeutet, wobei die vorstehenden Reste ihrerseits mit Halogen, -OH, -CN, substituiert sein können und
x eine ganze Zahl 1, 2, 3, 4, 5, 6, 7, 8, 9 oder 10 bedeutet
y eine ganze Zahl 1, 2, 3, 4, 5, 6, 7, 8, 9 oder 10 bedeutet
und/oder der Formel

worin
R eine Bindung, eine C1–C15-Alkylgruppe, C1–C15-Alkoxygruppe, Ethylenoxygruppe oder C5–C20-Aryl oder Heteroarylgruppe bedeutet, wobei die vorstehenden Reste ihrerseits mit Halogen, -OH, COOZ, -CN, NZ₂ substituiert sein können,
Z unabhängig voneinander Wasserstoff, C1–C15-Alkylgruppe, C1–C15-Alkoxygruppe, Ethylenoxygruppe oder C5–C20-Aryl oder Heteroarylgruppe bedeutet, wobei die vorstehenden Reste ihrerseits mit Halogen, -OH, -CN, substituiert sein können und
x eine ganze Zahl 1, 2, 3, 4, 5, 6, 7, 8, 9 oder 10 bedeutet.The vinyl-containing phosphonic acid used in step A) is preferably a compound of the formula

wherein
R denotes a bond, a C1-C15-alkyl group, C1-C15-alkoxy group, ethyleneoxy group or C5-C20-aryl or heteroaryl group, where the above radicals can in turn be substituted by halogen, -OH, COOZ, -CN, NZ ₂ ,
Z is independently hydrogen, C1-C15-alkyl group, C1-C15-alkoxy group, ethyleneoxy group or C5-C20-aryl or heteroaryl group -, where the above radicals can in turn be substituted with halogen, -OH, -CN, and
x represents an integer 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10
y represents an integer 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10
and / or the formula

wherein
R denotes a bond, a C1-C15-alkyl group, C1-C15-alkoxy group, ethyleneoxy group or C5-C20-aryl or heteroaryl group, the above radicals in turn being substituted by halogen, -OH, COOZ, -CN, NZ ₂ ,
Z independently of one another denotes hydrogen, C1-C15-alkyl group, C1-C15-alkoxy group, ethyleneoxy group or C5-C20-aryl or heteroaryl group, the above radicals in turn being substituted by halogen, -OH, -CN, and
x represents an integer 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10.

worin
R eine Bindung, eine C1–C15-Alkylgruppe, C1–C15-Alkoxygruppe, Ethylenoxygruppe oder C5–C20-Aryl oder Heteroarylgruppe bedeutet, wobei die vorstehenden Reste ihrerseits mit Halogen, -OH, COOZ, -CN, NZ₂ substituiert sein können,
Z unabhängig voneinander Wasserstoff, C1–C15-Alkylgruppe, C1–C15-Alkoxygruppe, Ethylenoxygruppe oder C5–C20-Aryl oder Heteroarylgruppe bedeutet, wobei die vorstehenden Reste ihrerseits mit Halogen, -OH, -CN, substituiert sein können und
x eine ganze Zahl 1, 2, 3, 4, 5, 6, 7, 8, 9 oder 10 bedeutet
y eine ganze Zahl 1, 2, 3, 4, 5, 6, 7, 8, 9 oder 10 bedeutet
und/oder der Formel

worin
R eine Bindung, eine C1–C15-Alkylgruppe, C1–C15-Alkoxygruppe, Ethylenoxygruppe oder C5-C20-Aryl oder Heteroarylgruppe bedeutet, wobei die vorstehenden Reste ihrerseits mit Halogen, -OH, COOZ, -CN, NZ₂ substituiert sein können,
Z unabhängig voneinander Wasserstoff, C1–C15-Alkylgruppe, C1–C15-Alkoxygruppe, Ethylenoxygruppe oder C5–C20-Aryl oder Heteroarylgruppe bedeutet, wobei die vorstehenden Reste ihrerseits mit Halogen, -OH, -CN, substituiert sein können und
x eine ganze Zahl 1, 2, 3, 4, 5, 6, 7, 8, 9 oder 10 bedeutet.The vinyl-containing sulfonic acid used in step A) is preferably a compound of the formula

wherein
R denotes a bond, a C1-C15-alkyl group, C1-C15-alkoxy group, ethyleneoxy group or C5-C20-aryl or heteroaryl group, the above radicals in turn being substituted by halogen, -OH, COOZ, -CN, NZ ₂ ,
Z independently of one another denotes hydrogen, C1-C15-alkyl group, C1-C15-alkoxy group, ethyleneoxy group or C5-C20-aryl or heteroaryl group, the above radicals in turn being substituted by halogen, -OH, -CN, and
x represents an integer 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10
y represents an integer 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10
and / or the formula

wherein
R denotes a bond, a C1-C15-alkyl group, C1-C15-alkoxy group, ethyleneoxy group or C5-C20-aryl or heteroaryl group, where the above radicals can in turn be substituted by halogen, -OH, COOZ, -CN, NZ ₂ ,
Z independently of one another denotes hydrogen, C1-C15-alkyl group, C1-C15-alkoxy group, ethyleneoxy group or C5-C20-aryl or heteroaryl group, the above radicals in turn being substituted by halogen, -OH, -CN, and
x represents an integer 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10.

The mixture prepared in step A) can additionally other organic solvents contain. these can have a positive impact on processability. In particular, by Add the organic solvent the solubility of the polymer can be improved. The content of vinyl-containing phosphonic acid in such solutions is at least 5% by weight, preferably at least 10% by weight, particularly preferably between 10 and 97% by weight.

Commercial vinylphosphonic acid such as this is available, for example, from Aldrich or Clariant GmbH, used. The vinylphosphonic acid has a purity of more than 90%, preferably more than 97% purity on.

The content of vinyl-containing sulfonic acid in such solutions is at least 5% by weight, preferably at least 10% by weight, particularly preferably between 10 and 97% by weight.

Commercial vinyl sulfonic acid is particularly preferably used. The vinyl sulfonic acid has a purity of more than 90%, preferably more than 97% purity on.

The mixture prepared in step A) preferably comprises at least 10% by weight, in particular at least 20 to 80 wt .-% vinyl-containing phosphonic acid and vinyl-containing sulfonic acid.

According to a special aspect of the The present invention is the ratio of vinyl-containing phosphonic acid to vinyl-containing sulfonic acid in the range of 1:99 up to 99: 1, preferably 1:50 up to 50: 1 on the weight, without any limitation.

In the used according to the invention aromatic and heteroaromatic tetra-amino compounds it is preferably 3,3 ', 4,4'-tetraaminobiphenyl, 2,3,5,6-tetraaminopyridine, 1,2,4,5-tetraaminobenzene, 3,3 ', 4,4'-tetraaminodiphenyl sulfone, 3,3', 4,4'-tetraaminodiphenyl ether, 3,3 ', 4,4'-tetraaminobenzophenone, 3,3 ', 4,4'-tetraaminodiphenylmethane and 3,3', 4,4'-tetraaminodiphenyldimethylmethane and their Salts, especially their mono-, di-, tri- and tetrahydrochloride derivatives.

In the used according to the invention aromatic carboxylic acids it is dicarboxylic acids and tri-carboxylic acids and tetra-carboxylic acids or their esters or their anhydrides or their acid chlorides. The term aromatic carboxylic acids includes equally also heteroaromatic carboxylic acids. The aromatic dicarboxylic acids are preferably isophthalic acid, terephthalic acid, phthalic acid, 5-hydroxyisophthalic, 4-hydroxyisophthalic acid, 2-hydroxyterephthalic acid, 5-aminoisophthalic acid, 5-N, N-dimethylaminoisophthalic acid, 5-N, N-diethylaminoisophthalic acid, 2,5-dihydroxyterephthalic acid, 2,6-dihydroxyisophthalic acid, 4,6-dihydroxyisophthalic acid, 2,3- Dihydroxyphthalic acid, 2,4-dihydroxyphthalic acid. 3,4-dihydroxyphthalic acid, 3-fluorophthalic acid, 5-fluoroisophthalic acid, 2-fluoroterphthalic acid, tetrafluorophthalic acid, tetrafluoroisophthalic acid, tetrafluoroterephthalic acid, 1,4-naphthalene dicarboxylic acid, 1,5-naphthalene dicarboxylic acid, 2,6-naphthalene dicarboxylic acid, 2,7-diacarbonic acid, 2,7 1,8-dihydroxynaphthalene-3,6-dicarboxylic acid, diphenyl ether-4,4'-dicarboxylic acid, benzophenone-4,4'-dicarboxylic acid, diphenyl sulfone-4,4'-dicarboxylic acid, biphenyl-4,4'-dicarboxylic acid, 4- Trifluoromethylphthalic acid, 2,2-bis (4-carboxyphenyl) hexafluoropropane, 4,4'-stilbene dicarboxylic acid, 4-carboxycinnamic acid, or their C1-C20-alkyl esters or C5-C12-Ary1 esters, or their acid anhydrides or their acid chlorides. at the aromatic tri-, tetracarboxylic acids or their C1 – C20 alkyl esters or C5-C12 aryl esters or their acid anhydrides or their acid chlorides it is preferably 1,3,5-benzene-tricarboxylic acid (Trimesic acid), 1,2,4-benzene-tricarboxylic acid (Trimellitic acid), (2-carboxyphenyl) iminodiacetic acid, 3,5,3'-biphenyltricarboxylic acid, 3,5,4'-biphenyltricarboxylic acid.

With aromatic tetracarboxylic acids or their C1 – C20 alkyl esters or C5-C12 aryl esters or their acid anhydrides or their acid chlorides it is preferably 3,5,3 ', 5'-biphenyltetracarboxylic acid, 1,2,4,5-benzene tetracarboxylic acid, benzophenone, 3,3 ', 4,4'-biphenyltetracarboxylic acid, 2,2 ', 3,3'-biphenyltetracarboxylic acid, 1,2,5,6-naphthalene tetracarboxylic acid, 1,4,5,8-naphthalene tetracarboxylic acid.

In the used according to the invention heteroaromatic carboxylic acids are heteroaromatic dicarboxylic acids and tricarboxylic acids and Tetracarboxylic acids or their esters or their anhydrides. As heteroaromatic carboxylic acids understood aromatic systems which contain at least one nitrogen, Contain oxygen, sulfur or phosphorus atom in the aromatics. Preferably is pyridine-2,5-dicarboxylic acid, pyridine-3,5-dicarboxylic acid, pyridine-2,6-dicarboxylic acid, pyridine-2,4-dicarboxylic acid, 4-phenyl-2,5-pyridinedicarboxylic acid, 3,5- Pyrazole dicarboxylic acid, 2.6 Pyrimidine dicarboxylic acid, 2,5 pyrazine dicarboxylic acid, 2,4,6 pyridine tricarboxylic acid, benzimidazole 5,6 dicarboxylic acid. Such as their C1 – C20 alkyl esters or C5-C12 aryl esters, or their acid anhydrides or their acid chlorides.

The content of tricarboxylic acid or Tetracarboxylic acids (based on the dicarboxylic acid used) is between 0 and 30 mol%, preferably 0.1 and 20 mol%, in particular 0.5 and 10 mol%.

In the used according to the invention aromatic and heteroaromatic diaminocarboxylic acids it is preferably diaminobenzoic acid and its mono- and dihydrochloride derivatives.

Mixtures are preferred in step A) use of at least 2 different aromatic carboxylic acids. Mixtures which are not only aromatic but also particularly preferred carboxylic acids also heteroaromatic carboxylic acids contain. The mixing ratio of aromatic carboxylic acids to heteroaromatic carboxylic acids is between 1:99 and 99: 1, preferably 1:50 up to 50: 1.

This mixture is are in particular mixtures of heteroaromatic dicarboxylic acids and aromatic dicarboxylic acids. Non-limiting examples of this are isophthalic acid, terephthalic acid, phthalic acid, 2,5-dihydroxyterephthalic acid, 2,6-dihydroxyisophthalic acid, 4,6-dihydroxyisophthalic acid, 2,3-dihydroxyphthalic acid, 2,4-dihydroxyphthalic acid. 3,4-dihydroxyphthalic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, diphenic acid, 1,8-dihydroxynaphthalene-3,6-dicarboxylic acid, diphenyl ether-4,4 ' -dicarboxylic acid, benzophenone-4,4'-dicarboxylic acid, diphenylsulfone-4,4'-dicarboxylic acid, biphenyl-4,4'dicarboxylic acid, 4-trifluoromethylphthalic acid, pyridine-2,5-dicarboxylic acid, pyridine-3,5-dicarboxylic acid, pyridine -2,6-dicarboxylic acid, pyridine-2,4-dicarboxylic acid, 4-phenyl-2,5-pyridinedicarboxylic acid, 3,5-pyrazole dicarboxylic acid, 2,6-pyrimidinedicarboxylic acid, 2,5-pyrazinedicarboxylic acid.

Should have the highest possible molecular weight can be achieved, the molar ratio of carboxylic acid groups to amino groups in the implementation of tetra-amino compounds one or more aromatic carboxylic acids or their esters, the at least two acid groups contain per carboxylic acid monomer, preferably nearby of 1: 2.

The mixture prepared in step A) preferably comprises at least 10% by weight, in particular 20 to 80% % By weight of monomers for the production of polyazoles.

worin
Ar gleich oder verschieden sind und für eine vierbindige aromatische oder heteroaromatische Gruppe, die ein- oder mehrkernig sein kann,
Ar¹ gleich oder verschieden sind und für eine zweibindige aromatische oder heteroaromatische Gruppe, die ein- oder mehrkernig sein kann,
Ar^{2 gleich oder verschieden sind und für eine zwei oder dreibindige aromatische} oder heteroaromatische Gruppe, die ein- oder, mehrkernig sein kann,
Ar³ gleich oder verschieden sind und für eine dreibindige aromatische oder heteroaromatische Gruppe, die ein- oder mehrkernig sein kann,
Ar⁴ gleich oder verschieden sind und für eine dreibindige aromatische oder heteroaromatische Gruppe, die ein- oder mehrkernig sein kann,
Ar⁵ gleich oder verschieden sind und für eine vierbindige aromatische oder heteroaromatische Gruppe, die ein- oder mehrkernig sein kann,
Ar⁶ gleich oder verschieden sind und für eine zweibindige aromatische oder heteroaromatische Gruppe, die ein- oder mehrkernig sein kann,
Ar⁷ gleich oder verschieden sind und für eine zweibindige aromatische oder heteroaromatische Gruppe, die ein- oder mehrkernig sein kann,
Ar⁸ gleich oder verschieden sind und für eine dreibindige aromatische oder heteroaromatische Gruppe, die ein- oder mehrkernig sein kann,
Ar⁹ gleich oder verschieden sind und für eine zwei- oder drei- oder vierbindige aromatische oder heteroaromatische Gruppe, die ein- oder mehrkernig sein kann,
Ar¹⁰ gleich oder verschieden sind und für eine zwei- oder dreibindige aromatische oder heteroaromatische Gruppe, die ein- oder mehrkernig sein kann,
Ar¹¹ gleich oder verschieden sind und für eine zweibindige aromatische oder heteroaromatische Gruppe, die ein- oder mehrkernig sein kann,
X gleich oder verschieden ist und für Sauerstoff, Schwefel oder eine Aminogruppe, die ein Wasserstoffatom, eine 1–20 Kohlenstoffatome aufweisende Gruppe, vorzugsweise eine verzweigte oder nicht verzweigte Alkyl- oder Alkoxygruppe, oder eine Arylgruppe als weiteren Rest trägt
R gleich oder verschieden für Wasserstoff, eine Alkylgruppe und eine aromatische Gruppe steht und
n, m eine ganze Zahl größer gleich 10, bevorzugt größer gleich 100 ist.The polymer based on polyazole formed in step B) contains recurring azole units of the general formula (I) and / or (II) and / or (III) and / or (IV) and / or (V) and / or (VI) and / or (VII) and / or (VIII) and / or (IX) and / or (X) and / or (XI) and / or (XII) and / or (XIII) and / or (XIV) and / or (XV) and / or (XVI) and / or (XVI) and / or (XVII) and / or (XVIII) and / or (XIX) and / or (XX) and / or (XXI) and / or ( XXII)

wherein
Ar are the same or different and are a four-membered aromatic or heteroaromatic group which may be mononuclear or polynuclear,
Ar ^{1 are the} same or different and are for a double-bonded aromatic or heteroaromatic group which can be mononuclear or polynuclear,
Ar ^{2 are the same or different and are for a two or three-membered aromatic} or heteroaromatic group which can be mono- or polynuclear,
Ar ^{3 are the} same or different and are for a three-membered aromatic or heteroaromatic group which can be mononuclear or polynuclear,
Ar ^{4 are the} same or different and are for a three-membered aromatic or heteroaromatic group which may be mononuclear or polynuclear,
Ar ^{5 are the} same or different and are a four-membered aromatic or heteroaromatic group which may be mononuclear or polynuclear,
Ar ^{6 are the} same or different and are for a double-bonded aromatic or heteroaromatic group which can be mononuclear or polynuclear,
Ar ^{7 are the} same or different and are for a double-bonded aromatic or heteroaromatic group which may be mononuclear or polynuclear,
Ar ^{8 are the} same or different and are for a three-membered aromatic or heteroaromatic group which can be mononuclear or polynuclear,
Ar ^{9 are the} same or different and are for a two- or three- or four-membered aromatic or heteroaromatic group which may be mononuclear or polynuclear,
Ar ^{10 are the} same or different and are for a di- or tri-bonded aromatic or heteroaromatic group which can be mono- or polynuclear,
Ar ^{11 are the} same or different and are for a divalent aromatic or heteroaromatic group, which can be mononuclear or polynuclear,
X is the same or different and for oxygen, sulfur or an amino group which carries a hydrogen atom, a group having 1-20 carbon atoms, preferably a branched or unbranched alkyl or alkoxy group, or an aryl group as a further radical
R represents the same or different hydrogen, an alkyl group and an aromatic group and
n, m is an integer greater than or equal to 10, preferably greater than or equal to 100.

Preferred aromatic or heteroaromatic Groups are derived from benzene, naphthalene, biphenyl, diphenyl ether, Diphenylmethane, Diphenyldimethylmethan, Bisphenon, Diphenylusulfon, Quinoline, pyridine, bipyridine, pyridazine, pyrimidine, pyrazine, triazine, Tetrazine, pyrol, pyrazole, anthracene, benzopyrrole, benzotriazole, benzooxathiadiazole, Benzooxadiazole, benuzopyridine, benzopyrazine, benzapyrazidine, benzopyrimidine, Benzopyrazine, benzotriazine, indolizine, quinolizine, pyridopyridine, Imidazopyrimidine, pyrazinopyrimidine, carbazole, aciridine, phenazine, Benzoquinoline, phenoxazine, phenothiazine, acridizine, benzopteridine, Phenanthroline and phenanthrene, which are also optionally substituted could be, from.

The substitution pattern of Ar ¹ , Ar ⁴ , Ar ⁶ , Ar ⁷ , Ar ⁸ , Ar ⁹ , Ar ¹⁰ , Ar ^{11 is} arbitrary, in the case of phenylene, for example, Ar ¹ , Ar ⁴ , Ar ⁶ , Ar ⁷ , Ar ⁸ , Ar ⁹ , Ar ¹⁰ , Ar ^{11 are} ortho-, meta- and para-phenylene. Particularly preferred groups are derived from benzene and biphenylene, which may also be substituted.

Preferred alkyl groups are short chain Alkyl groups with 1 to 4 carbon atoms, such as. B. methyl, ethyl, n- or i-propyl and t-butyl groups.

Preferred aromatic groups are Phenyl or naphthyl groups. The alkyl groups and the aromatic Groups can be substituted.

Preferred substituents are halogen atoms such as B. fluorine, amino groups, hydroxyl groups or short-chain alkyl groups such as B. methyl or ethyl groups.

Recurring polyazoles are preferred Units of the formula (n in which the radicals X are within a recurring Unit are the same.

In principle, the polyazoles can also be different have recurring units, for example in their Distinguish rest X. However, it preferably only has the same residues X in a recurring unit.

Other preferred polyazole polymers are polyimidazoles, polybenzthiazoles, polybenzoxazoles, polyoxadiazoles, Polyquinoxalines, polythiadiazoles poly (pyridines), poly (pyrimidines), and poly (tetrazapyrene).

In another embodiment In the present invention, the polymer containing recurring Azo units are a copolymer or a blend that is at least two units of the formula (I) to (XXII) contains that are different from each other. The polymers can be used as Block copolymers (diblock, triblock), statistical copolymers, periodic Copolymers and / or alternating polymers are present.

In a particularly preferred embodiment In the present invention, the polymer containing recurring Azole units is a polyazole containing only units of formula (I) and / or (II) contains.

The number of repeating azole units an integer greater than or equal to 10 in the polymer is preferably particularly preferred Polymers contain at least 100 repeating azole units.

wobei n und m eine ganze Zahl größer gleich 10, vorzugsweise größer gleich 100 ist.Polymers containing recurring benzimidazolein are within the scope of the present invention preferred. Some examples of the extremely useful polymers containing recurring benzimidazole units are represented by the following formulas:

where n and m is an integer greater than or equal to 10, preferably greater than or equal to 100.

The means described available Polyazoles, but especially the polybenzimidazoles, stand out characterized by a high molecular weight. Measured as intrinsic viscosity is this at least 1.4 dl / g and is therefore significantly above that of commercially available Polybenzimidazole (IV <1.1 dl / g).

In this respect, the mixture according to step A) also tricarboxylic acids or tetracarboxylic acid contains becomes a branching / crosslinking of the polymer formed achieved. This carries to improve the mechanical property.

The mixture obtained in step A) according to step B) to a temperature of up to 350 ° C, preferably up to 280 ° C and especially preferably in the range of 200 ° C up to 250 ° C heated. An inert gas, for example nitrogen or an inert gas, such as neon, argon, is used.

It has also been shown that when aromatic dicarboxylic acids (or heteroaromatic dicarboxylic acids) are used, such as isophthalic acid, terephthalic acid, 2,5-dihydroxyterephthalic acid, 4,6-dihydroxyisophthalic acid, 2,6-dihydroxyisophthalic acid, diphenic acid, 1,8-dihydroxynaphthalene-3, 6-dicarboxylic acid, diphenyl ether-4,4'-dicarboxylic acid, benzophenone-4,4'-dicarboxylic acid, diphenylsulfone-4,4'-dicarboxylic acid, biphenyl-4,4'-dicarboxylic acid, 4-trifluoromethylphthalic acid, pyridine-2,5- dicarboxylic acid, pyridine-3,5-dicarboxylic acid, pyridine-2,6-dicarboxylic acid, pyridine-2,4-dicarboxylic acid, 4-phenyl-2,5-pyridinedicarboxylic acid, 3,5-pyrazole dicarboxylic acid, 2,6-pyrimidinedicarboxylic acid, 2, 5-pyrazine dicarboxylic acid,
the temperature in step C) - or if the formation of oligomers and / or polymers is already desired in step A) - is favorable in the range of up to 300 ° C., preferably between 100 ° C. and 250 ° C.

Step B) serves to react the carboxylic acid groups with the amino groups. This reaction releases water. According to a particular aspect of the present invention, the water formed in step B) is removed from the reaction equilibrium. Methods are widely used in the professional world. For example, the water can be distilled off. Furthermore, the water can be bound by desiccants. Depending on the type of desiccant, it can remain in the reaction mixture or be separated from the reaction mixture. Among others, phosphorus pentoxide (P ₂ O ₅ ) or silica gel can be used as drying agents.

In a variant of the procedure can the warming according to step B) after the formation of a flat Formed according to step C) done.

In another embodiment of the invention capable of networking Monomers are used. Depending on the temperature stability of the monomer can this the mixture according to step A) or after the preparation of the polyazoles according to step B). About that can out that empowered to network Monomers also on the flat Formed according to step C) are applied.

In the case of the monomers capable of crosslinking it is particularly compounds that have at least 2 carbon-carbon Have double bonds. Dienes, trienes, tetraenes, Dimethyl acrylates, trimethyl acrylates, tetramethyl acrylates, diacrylates, Triacrylates, tetraacrylates.

Dienes, trienes and tetraenes of the formula are particularly preferred

Dimethylacrylates, Trimethylycrylate, Tetramethylacrylate of the formula

worin
R eine C1–C15-Alkylgruppe, C5–C20-Aryl oder Heteroarylgruppe, NR', -SO₂, PR', Si(R')₂ bedeutet, wobei die vorstehenden Reste ihrerseits substituiert sein können,
R' unabhängig voneinander Wasserstoff, eine (C1–C15-Alkylgruppe, C1–C15-Alkoxygruppe, C5–C20-Aryl oder Heteroarylgruppe bedeutet und
n mindestens 2 ist.Diacrylates, triacrylates, tetraacrylates of the formula

wherein
R represents a C1-C15-alkyl group, C5-C20-aryl or heteroaryl group, NR ', -SO ₂ , PR', Si (R ') ₂ , where the above radicals can in turn be substituted,
R 'independently represents hydrogen, a (C1-C15 alkyl group, C1-C15 alkoxy group, C5-C20 aryl or heteroaryl group and
n is at least 2.

With the substituents of the above R is preferably halogen, hydroxyl, carboxy, Carboxyl, carboxyule esters, nitriles, amines, silyl, siloxane residues.

Crosslinkers are particularly preferred Allyl methacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate Triethylene glycol dimethacrylate, tetra- and polyethylene glycol dimethacrylate, 1,3-butanediol dimethacrylate, glycerol dimethacrylate, diurethane dimethacrylate, Trimethylpropane trimethacrylate, Ebacryl, N ', N-methylenebisacrylamide, Carbinol, butadiene, isoprene, chloroprene, divinylbenzene and / or Bisphenol A dimethacrylate.

The crosslinkers are between 0.5 up to 30 wt .-%, based on the sum of vinyl-containing phosphonic acid and vinyl-containing sulfonic acid, used.

The mixture produced in step A) and / or step B) can also contain dispersed or suspended polymer. The preferred polymers include, inter alia, polyethylene, polypropylene, poly (1-butene), poly (4-methyl-1-pentene), poly (isobutylene), polybutadiene, poly (isoprene), poly (chloroprene), poly (2, 3-dimethylbutadiene, polyalkanamer, polyacetylene, polyphenylene, poly (p-xylylene), phenolic resins, polyarmethylene, coumarone / indene resins, resin oil resins, pinene resins, polystyrene, polymethylstyrene, polyvinyl acetate, polyvinyl alcohol, polyvinyl acetate, polyvinyl ether, polyvinyl ether (N-vinylacetamide), polyvinylimidazole, polyvinylcarbazole, polyvinylpyrrolidone, polyvinylpyridine, polyvinylchloride, polyvinylidene chloride, polytetrafluoroethylene, copolymers of PTFE with hexafluoropropylene, with perfluoropropylvinylether, with trifluoronitrosomethane, polyolefinoxychloride, polychloride, polyvinylchloride, vinyl chloride, Polyacrolein, polyacrylamide, polyacrylonitrile, polycyanacrylates, polymethyl methacrylate, polyhydro xyethyl methacrylate, polymethacrylimide; Polymers with CO bonds in the main chain, for example polyacetate, polyoxymethylene, polyether, polypropylene oxide, polyepichlorohydrin, phenoxy resins, epoxy resins, polytetrahydrofuran, furan resins, polyphenylene oxide, polyether ketone, phenol aralkyl resins, polyhydroxyacetic acid, polypropionic acid, polypivalolactone polycaprolactone, Polymalonic acid, polycarbonate, polyhydroxybenzoate, polyethylene terephthalate, polybutylene terephthalate;
Polymeric CS bonds in the main chain, for example polysulfide ether, polyphenylene sulfide, polyether sulfone;
Polymeric CN bonds in the main chain, for example polyimines, polyisocyanides, polyetherimine, polyaniline, polyamides, polyureas, amino resins, polyhydrazides, polyurethanes, polyimides, polyazoles, polyazines; and inorganic polymers, for example polysilanes, polycarbosilanes, polysiloxanes, polysilicic acid, polysilicates, silicones, polyphosphazenes and polythiazyl.

To further improve the application technology Properties can the membrane additionally still fillers, especially proton-conducting fillers, as well as additional acids be added. The addition can, for example, in step A), Step B) and / or step C) take place. Furthermore, these additives, if this is in liquid Form present, can also be added after the polymerization according to step D).

Non-limiting examples of proton-conducting fillers are
Sulfates such as: CsHSO ₄ , Fe (SO ₄ ) ₂ , (NH ₄ ) ₃ H (SO ₄ ) ₂ , LiHSO ₄ , NaHSO ₄ , KHSO ₄ , RbSO ₄ , LiN ₂ H ₅ SO ₄ , NH ₄ HSO ₄ ,
Phosphates such as Zr ₃ (PO ₄ ) ₄ , Zr (HPO ₄ ) ₂ , HZr ₂ (PO ₄ ) ₃ , UO ₂ PO ₄ .3H ₂ O, H ₈ UO ₂ PO ₄ , Ce (HPO ₄ ) ₂ , Ti ( HPO ₄ ) ₂ , KH ₂ PO ₄ , NaH ₂ PO ₄ , LiH ₂ PO ₄ , NH ₄ H ₂ PO ₄ , CsH ₂ PO ₄ , CaHPO ₄ , MgHPO ₄ , HSbP ₂ O ₈ , HSb ₃ P ₂ O ₁₄ , H ₅ Sb ₅ P ₂ O ₂₀ ,
Polyacid such as H ₃ PW ₁₂ O ₄₀ · nH ₂ O (n = 21-29), H ₃ SiW ₁₂ O ₄₀ · nH ₂ O (n = 21-29), H _x WO ₃ , HSbWO ₆ , H ₃ PMo ₁₂ O ₄₀ , H ₂ Sb ₄ O ₁₁ , HTaWO ₆ , HNbO ₃ , HTiNbO ₅ , HTiTaO ₅ , HSbTeO ₆ , H ₅ Ti ₄ O ₉ , HSbO ₃ , H ₂ MoO ₄
Selenites and arsenides such as (NH ₄ ) ₃ H (SeO ₄ ) ₂ , UO ₂ AsO ₄ , (NH ₄ ) ₃ H (SeO ₄ ) ₂ , KH ₂ AsO ₄ , Cs ₃ H (SeO ₄ ) ₂ , Rb ₃ H (SeO ₄ ) ₂ ,
Oxides such as Al ₂ O ₃ , Sb ₂ O ₅ , ThO ₂ , SnO ₂ , ZrO ₂ , MoO ₃
Silicates such as zeolites, zeolites (NH ₄ +), layered silicates, framework silicates, H-natrolites, H-mordenites, NH ₄ -analyses, NH ₄ -sodalites, NH ₄ -galates, H-montmorillonites
Acids such as HClO ₄ , SbF ₅
Fillers such as carbides, in particular SiC, Si ₃ N ₄ , fibers, in particular glass fibers, glass powders and / or polymer fibers, preferably based on polyazoles.

These additives can be used in the proton-conducting Polymer membrane in usual Amounts may be included, but the positive properties, like high conductivity, long service life and high mechanical stability of the membrane due to addition from too big Amounts of additives should not be affected too much. In general comprises the membrane after the polymerization according to step D) at most 80 wt .-%, preferably at most 50% by weight and particularly preferably at most 20% by weight of additives.

This membrane can also be used perfluorinated sulfonic acid additives (preferably 0.1-20% by weight, preferably 0.215% by weight, very preferably 0.2-10% by weight). This Additives lead to improve performance, near the cathode to increase the oxygen solubility and oxygen diffusion and to reduce the adsorption of phosphoric acid and phosphate to platinum. (Electrolyte additives for phosphoric acid fuel cells. Gang, Xiao; Hjuler, H. A .; Olsen, C .; Berg, R. W .; Bjerrum, N. J. Chem. Dep. A, Tech. Univ. Denmark, Lyngby, Den. J. Electrochem. Soc. (1993), 140 (4), 896-902 and Perfluorosulfonimide as an additive in phosphoric acid fuel cell. Razaq, M .; Razaq, A .; Yeager, E .; DesMarteau, Darryl D .; Singh, S. Case Cent. Electrochem. Sci., Case West. Reserve University, Cleveland, OH, USA. J. Electrochem. Soc. (1989), 136 (2), 385-90.)

Non-limiting examples of persulfonated Additives are: trifluomethanesulfonic acid, potassium trifluoromethanesulfonate, Sodium trifluoromethanesulfonate, lithium trifluoromethanesulfonate, ammonium trifluoromethanesulfonate, Potassium perfluorohexane sulfonate, sodium perfluorohexane sulfonate, lithium perfluorohexane sulfonate, Ammonium perfluorohexane sulfonate, perfluorohexane sulfonic acid, potassium nonafluorobutane sulfonate, Sodium nonafluorobutane sulfonate, lithium nonafluorobutane sulfonate, ammonium nonafluorobutane sulfonate, Cäsiumnonafluorbutansulfonat, Triethylammonium perfluorohexasulfonate, perflurosulfoimide and Nafion.

The formation of the flat structure according to step C) takes place by means of measures known per se (pouring, spraying, knife coating, Extrusion) from the prior art for polymer film production are known. As a carrier are all suitable carriers which can be described as inert under the conditions.

To adjust the viscosity, the solution optionally with water or an easily evaporable organic Lösungsmittei be transferred. This allows the viscosity to reach the desired value adjusted and the formation of the membrane can be facilitated.

The thickness of the flat structure is between 15 and 2000 μm, preferably between 30 and 1500 μm, in particular between 50 and 1200 μm.

The polymerization of the vinyl-containing phosphonic and vinyl-containing sulfonic acid in step D) is preferably radical. The radical formation can be thermal, photochemical, chemical and / or electrochemical respectively.

For example, a starter solution which contains at least one substance capable of forming radicals can be added to the mixture after the solution and / or dispersion have been heated in accordance with step B). Furthermore, a starter solution can be applied to the flat structure obtained after step C). This can be done by means of measures known per se (e.g. spraying, diving, etc.) from the stand are known in the art.

Suitable radical formers are azo compounds, peroxy compounds, persulfate compounds or azoamidines. Non-limiting examples are dibenzoyl peroxide, dicumol peroxide, cumene hydroperoxide, diisopropyl peroxidicarbonate, bis (4-t-butylcyclohexyl) peroxidicarbonate, dipotassium persulfate, ammonium peroxydisulfate, 2,2'-azobis (2-methylpropionitrile) (AIBN), methylbenzene peroxides, and benzenzyl peroxide, benzophenyl peroxide the radical generator available from DuPont under the names ^® Vazo and ^® Vazo WS.

Furthermore, radical formers can also be used which form radicals when irradiated. Preferred compounds include Igacure ^® 651 (2,2-dimethoxy-2-phenylacetophenone) and Igacure 184 ^® (1-benzoylcyclohexanol), each of the Fa. Ciba Geigy Corp. are commercially available.

Usually are between 0.0001 and 1 wt .-% (based on the vinyl-containing Phosphonic acid and vinyl-containing sulfonic acid) added to radical formers. The amount of radical generator can vary according to desired Degree of polymerization can be varied.

The polymerization can also by Exposure to IR or NIR (IR = InfraRot, i.e. light with a wavelength of more than 700 nm; NIR = Near IR, i.e. H. Light with a wavelength in the range from approx. 700 to 2000 nm or an energy in the range of approx. 0.6 up to 1.75 eV). Another method is radiation with beta rays. The radiation dose is between 5 and 200 kGy.

The polymerization is carried out at temperatures above room temperature (20 ° C) and less than 200 ° C, preferably at temperatures between 40 ° C and 150 ° C, in particular between 50 ° C and 120 ° C. The Polymerization is preferably carried out under normal pressure, but can also take place under the influence of pressure. The polymerization leads to a Consolidation of the flat Structure. Depending on the one you want The degree of polymerization is the areal Form a self-supporting membrane. The degree of polymerization is preferably at least 30 repetition units, in particular at least 50 repetition units, particularly preferably at least 100 repetition units.

The polymerization in step D) can lead to a decrease in the layer thickness. The thickness is preferably the self-supporting membrane between 10 and 1000 microns, preferably between 20 and 500 μm, in particular between 25 and 250 μm.

It is preferably according to step D) self-supporting membrane obtained, d. H. it can be worn by the wearer without damage solved and subsequently if necessary, be processed directly.

After the treatment according to step D) The membrane can be exposed to heat in the presence of atmospheric oxygen on the surface still networked. This hardening the membrane surface additionally improves the properties of the membrane. For this, the membrane to a temperature of at least 150 ° C, preferably at least 200 ° C and especially preferably heated to at least 250 ° C. The oxygen concentration in this process step is usually in the range from 5 to 50 vol .-%, preferably 10 to 40 vol .-%, without this restriction should be done.

Networking can also be done by acting of IR or NIR (IR = InfraRot, i.e. light with a wavelength of more than 700 nm; NIR = Near IR, i.e. H. Light with a wavelength in the range from approx. 700 to 2000 nm or an energy in the range of approx. 0.6 up to 1.75 eV). Another method is radiation with beta rays. The radiation dose is between 5 and 200 kGy.

Depending on the desired degree of crosslinking the duration of the crosslinking reaction is in a wide range. Generally this response time is in the range of 1 second to 10 hours, preferably 1 minute to 1 hour, without this a limitation should be done.

The polymer membrane according to the invention has improved Material properties the previously known doped polymer membranes. In particular show them in comparison with known undoped polymer membranes already an intrinsic conductivity. This justifies in particular due to the presence of phosphonic acid and sulfonic acid groups containing polymers.

The intrinsic conductivity of the membrane according to the invention is at least 0.001 S / cm, preferably at least 10 mS / cm, in particular at least 20 mS / cm at a temperature of 120 ° C. These intrinsic conductivity values can even at a temperature of 70 ° C be measured. To achieve these values at one temperature of 70 ° C can a membrane according to the invention be moistened. For example, this can be used as an energy source compound used, for example hydrogen or methanol, be provided with a proportion of water. In many cases, however, it is sufficient also the water formed by the reaction around these conductivity values to achieve.

The specific conductivity is measured by means of impedance spectroscopy in a 4-pole arrangement in potentiostatic mode and using platinum electrodes (wire, 0.25 mm diameter). The distance between the current-consuming electrodes is 2 cm. The spectrum obtained is evaluated using a simple model consisting of a parallel arrangement of an ohmic resistor and a capacitor. The sample cross-section of the phosphoric acid-doped membrane is measured immediately before the sample assembly. To measure the temperature dependence, the measuring cell is brought to the desired temperature in an oven and via a Pt-100 positioned in the immediate vicinity of the sample Controlled thermocouple. After reaching the temperature, the sample is kept at this temperature for 10 minutes before starting the measurement.

Another subject of the present Invention are ionomers based on phosphonic acid and sulfonic acid groups containing polymers that can be made from such a solution. To do this instead of a flat one Formed in step C) this polymerized directly, the polymerization also in an inert solvent can be carried out as a suspension polymerization. The starter will be the solution added after step B).

These ionomers are suitable as additives for catalyst mixtures for the Use in fuel cells.

Possible areas of application of the intrinsically according to the invention conductive Polymer membranes and the ionomer include the use in fuel cells, in electrolysis, in capacitors and in Battery systems. Due to their property profile, the Polymer membranes preferably in fuel cells, in particular in DMBZ fuel cells (direct methanol fuel cells).

The present invention also relates to a membrane-electrode unit which has at least one polymer membrane according to the invention and / or the ionomer according to the invention. For more information on membrane electrode assemblies refer to the literature, particularly the patents US Patent No. 4,191,618 . US Pat No. 4,212,714 and US-A-4,333,805 directed. The references mentioned in the above references [ US-A-4; 191.518 . US Pat No. 4,212,714 and US-A-4,333,805 ] contained disclosure regarding the construction and manufacture of membrane electrode assemblies, as well as the electrodes, gas diffusion layers and catalysts to be selected is also part of the description.

In a variant of the present Invention can also form the membrane directly instead of on a support done on the electrode. The treatment according to step D) can hereby shortened accordingly or the amount of starter solution can be reduced because the Membrane no longer has to be self-supporting. Even such a membrane or an electrode with such a polymer membrane according to the invention is coated is the subject of the present invention.

Furthermore it is also possible Polymerization of the vinyl-containing phosphonic acid and vinyl-containing sulfonic acid in the perform laminated membrane electrode assembly. To do this, the solution is on the electrode is applied and coated with the second, if necessary also Electrode brought together and pressed. Then will the polymerization in the laminated membrane-electrode assembly performed as described above.

The coating has a thickness between 2 and 500 μm, preferably between 5 and 300 μm, in particular between 10 and 200 μm Has. That enables use in so-called micro fuel cells, in particular in DMBZ micro fuel cells.

An electrode coated in this way can in a membrane electrode unit, if necessary at least a polymer membrane according to the invention has to be installed.

In another variant, you can the membrane of the invention a catalytically active layer can be applied and this with a gas diffusion layer. To do this, follow the steps A) to D) a membrane is formed and the catalyst is applied. In a variant, the catalyst can be placed before or together with the starter solution be applied. These structures are also the subject of the present Invention.

In addition, education the membrane according to the steps A) to D) also on a support or a carrier film take place that already has the catalyst. After removing the carrier or the carrier film the catalyst is on the membrane of the invention. These structures are also the subject of the present invention.

Also the subject of the present Invention is a membrane electrode assembly that has at least one coated Electrode and / or at least one polymer membrane according to the invention in combination with another polymer membrane based on polyazoles or a polymer blend membrane containing at least one polymer Has base of polyazoles.

Claims (23)

Proton-conducting polymer membrane comprising polymers containing phosphonic acid and sulfonic acid groups obtainable by a process comprising the steps A) mixing one or more aromatic tetra-amino compounds with one or more aromatic carboxylic acids or their esters which contain at least two acid groups per carboxylic acid monomer, or mixing one or more aromatic and / or heteroaromatic diaminocarboxylic acids, in a mixture containing vinyl-containing phosphonic acid and vinyl-containing sulfonic acid, with the formation of a solution and / or dispersion, B) heating the solution and / or dispersion obtainable according to step A) under inert gas to temperatures of up to 350 ° C. with the formation of polyazole polymers, C) applying a layer using the mixture according to step A) and / or B) a carrier, D) polymerization of the vinyl-containing phosphonic acid and vinyl-containing sulfonic acid present in the sheet-like structure obtainable in step C). Membrane according to claim 1, characterized in that as aromatic tetra-amino compounds 3,3 ', 4,4'-tetraaminobiphenyl, 2,3,5,6-tetraaminopyridine, 1,2,4,5-tetraaminobenzene, 3,3 ', 4,4'-tetraaminodiphenyl, 3,3 ', 4,4'-tetraaminodiphenyl ether, 3,3', 4,4'-tetraaminobenzophenone, 3,3 ', 4,4'-tetraaminodiphenylmethane and 3,3 ', 4,4'-tetraaminodiphenyldimethylmethane. Membrane according to claim 1 or 2, characterized in that as aromatic carboxylic acids isophthalic acid, terephthalic acid, phthalic acid, 5-hydroxyisophthalic acid, 4-hydroxyisophthalic acid, 2-hydroxyterephthalic acid, 5-aminoisophthalic acid, 5-N, N-dimethylaminoisophthalic acid, 5-N, N-diethylamino acid , 5-dihydroxy terephthalic acid, 2,5-dihydroxyisophthalic acid, 2,3-dihydroxyisophthalic acid, 2,3-dihydroxyphthalic acid, 2,4-dihydroxyphthalic acid. 3,4-dihydroxyphthalic acid, 3-fluorophthalic acid, 5-fluoroisophthalic acid, 2-fluoroterphthalic acid, tetrafluorophthalic acid, tetrafluoroisophthalic acid, tetrafluoroterephthalic acid, 1,4-naphthalene dicarboxylic acid, 1,5-naphthalene dicarboxylic acid, 2,6-naphthalene dicarboxylic acid, 2,7-acid 1,8-dihydroxynaphthalene-3,6-dicarboxylic acid, diphenyl ether-4,4'-dicarboxylic acid, benzcphenone-4,4'-dicarboxylic acid, diphenyl sulfone-4,4'-dicarboxylic acid, biphenyl-4,4'-dicarboxylic acid, 4- Trifluoromethylphthalic acid, 2,2-bis (4-carboxyphenyl) hexafluoropropane, 4,4'-stilbene dicarboxylic acid, 4-carboxycinnamic acid, or their C1 – C20 alkyl esters or C5-C12 aryl esters, or their acid anhydrides or their acid chlorides be used. Membrane according to a or more of the preceding claims, characterized in that as an aromatic carboxylic acid tricarboxylic acids, their C1 – C20 alkyl esters or C5-C12 aryl esters or their acid anhydrides or their acid chlorides or tetracarboxylic acids, their C1 – C20 alkyl esters or C5-C12 aryl esters or their acid anhydrides or their acid chlorides be used. Membrane according to claim 4, characterized in that the aromatic carboxylic acid 1,3,5-benzenetricarboxylic acid (trimesic acid); 2,4,5-benzenetricarboxylic (trimellitic acid); (2-carboxyphenyl) iminodiacetic acid, 3,5,3'-biphenyltricarboxylic acid; 3,5,4'-biphenyltricarboxylic acid, 2,4,6-pyridine tricarboxylic acid, benzene-1,2,4,5-tetracarboxylic acids; Naphthalene-1,4,5,8-tetracarboxylic acids, 3,5,3 ', 5'-biphenyltetracarboxylic acids, benzophenonetetracarboxylic acid, 3,3', 4,4'-biphenyltetracarboxylic acid, 2,2 ', 3,3'-biphenyltetracarboxylic acid, 1,2,5,6-naphthalenetetracarboxylic acid and / or 1,4,5,8-naphthalene be used. Membrane according to 4, thereby characterized in that the content of tricarboxylic acid and / or tetracarboxylic acids between 0 and 30 mol%, preferably 0.1 and 20 mol%, in particular 0.5 and 10 mol%, based on the dicarboxylic acid used. Membrane according to claim 1, characterized in that as heteroaromatic carboxylic acids heteroaromatic dicarboxylic acids, tricarboxylic and / or tetracarboxylic acids are used, which contain at least one nitrogen, oxygen, Contain sulfur or phosphorus atom in the aromatics. Membrane according to claim 7, characterized in that pyridine-2,5-dicarboxylic acid, pyridine-3,5-dicarboxylic acid, pyridine-2,6-dicarboxylic acid, pyridine-2,4-dicarboxylic acid, 4-phenyl-2,5-pyridinedicarboxylic acid, 3, 5-pyrazole dicarboxylic acid, 2,6-pyrimidine dicarboxylic acid, 2,5-pyrazine dicarboxylic acid, 2,4,6-pyridine tricarboxylic acid, benzimidazole-5,6-dicarboxylic acid, and their C1 – C20 alkyl esters or C5-C12 aryl esters, or their acid anhydrides or their acid chlorides be used. Membrane according to claim 1, characterized in that as aromatic diaminocarboxylic acid diaminobenzoic acid and / or whose mono- and dihydrochloride derivatives are used. Membrane according to claim 1, characterized in that in step A) a vinyl-containing phosphonic acid of the formula

wherein R denotes a bond, a C1-C15-alkyl group, C1-C15-alkoxy group, ethyleneoxy group or C5-C20-aryl or heteroaryl group, the above radicals in turn being substituted by halogen, -OH, COOZ, -CN, NZ ₂ , Z independently of one another denotes hydrogen, C1-C15-alkyl group, C1-C15-alkoxy group, ethyleneoxy group or C5-C20-aryl or heteroaryl group, where the above radicals in turn can be substituted by halogen, -OH, -CN, and x is an integer 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 y means an integer 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 and / or of the formula

wherein R represents a bond, a C1-C15-alkyl group, C1-C15-alkoxy group, ethyleneoxy group or C5-C20-aryl or heteroaryl group, the above radicals in turn being substituted by halogen, -OH, COOZ, -CN, NZ ₂ , Z independently of one another denotes hydrogen, C1-C15-alkyl group, C1-C15-alkoxy group, ethyleneoxy group or C5-C20-aryl or heteroaryl group, the above radicals in turn being substituted by halogen, -OH, -CN, and x being a whole Number 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 means to be used. Membrane according to claim 1, characterized in that in step A) a vinyl-containing sulfonic acid of the formula

wherein R represents a bond, a C1-C15-alkyl group, C1-C15-alkoxy group, ethyleneoxy group or C5-C20-aryl or heteroaryl group, the above radicals in turn being substituted by halogen, -OH, COOZ, -CN, NZ ₂ , Z independently of one another denotes hydrogen, C1-C15-alkyl group, C1-C15-alkoxy group, ethyleneoxy group or C5-C20-aryl or heteroaryl group, the above radicals in turn being substituted by halogen, -OH, -CN, and x being a whole Number 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 means y an integer 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 and / or of the formula

wherein R represents a bond, a C1-C15-alkyl group, C1-C15-alkoxy group, ethyleneoxy group or C5-C20-aryl or heteroaryl group, the above radicals in turn being substituted by halogen, -OH, COOZ, -CN, NZ ₂ , Z independently of one another denotes hydrogen, C1-C15-alkyl group, C1-C15-alkoxy group, ethyleneoxy group or C5-C20-aryl or heteroaryl group, the above radicals in turn being substituted by halogen, -OH, -CN, and x being a whole Number 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 means to be used. Membrane according to claim 1, characterized in that capable of crosslinking monomers polymerized in step D), the at least 2 carbon-carbon Have double bonds. Membrane according to claim 1, characterized in that the generated in and / or step B) solution additionally contains dispersed and / or suspended polymer. Membrane according to claim 1, characterized in that in step B) a polymer based on Polyazole contains recurring azole units of the general formula (I) and / or (II) and / or (III) and / or (IV) and / or (V) and / or (VI) and / or (VII) and / or ( VIII) and / or (IX) and / or (X) and / or (XI) and / or (XII) and / or (XIII) and / or (XIV) and / or (XV) and / or (XVI) and / or (XVI) and / or (XVII) and / or (XVIII) and / or (XIX) and / or (XX) and / or (XXI) and / or (XXII)

in which Ar are identical or different and are for a tetra-aromatic or heteroaromatic group which can be mononuclear or polynuclear, Ar ^{1 are the} same or different and for a divalent aromatic or heteroaromatic group, which may be mono- or polynuclear, Ar ^{2 are the} same or different and for a divalent or trivalent aromatic or heteroaromatic group, which may be mono- or polynuclear, Ar ³ are the same or different and, for a three-membered aromatic or heteroaromatic group which may be mono- or polynuclear, Ar ^{4 are the} same or different and for a three-membered aromatic or heteroaromatic group which may be mono- or polynuclear, Ar ^{5 are the} same or different and for a four-membered aromatic or heteroaromatic group which may be mono- or polynuclear, Ar ^{6 are the} same or different and for a double-bonded aromatic or heteroaromatic group which may be mono- or polynuclear, Ar ^{7 are the} same or different and for a double-bonded aromatic or heteroaromatic group, which can be mononuclear or polynuclear, Ar ⁸ identical or are different and for a three-membered aromatic or heteroaromatic group, which may be mono- or polynuclear, Ar ^{9 are the} same or different and for a di-, tri-, or four- or four-membered aromatic or heteroaromatic group, which may be mono- or polynuclear, Ar ^{10 are the} same or different and are the same for a divalent or trivalent aromatic or heteroaromatic group which can be mono- or polynuclear, Ar ^{11 are the} same or different and for a divalent aromatic or heteroaromatic group which can be mono- or polynuclear or is different and for oxygen, sulfur or an amino group which has a hydrogen atom, a group having 1-20 carbon atoms, preferably a branched or unbranched alkyl or alkoxy group, or an aryl group as a further radical, R is identical or different for hydrogen, one Alkyl group and an aromatic group and n, m is an integer greater than or equal to 10, pref is greater than or equal to 100, is formed. Membrane according to claim 1, characterized in that in step B) a polymer selected from the Group polybenzimidazole, poly (pyridines), poly (pyrimidines), polyimidazoles, Polybenzthiazoles, polybenzoxazoles, polyoxadiazoles, polyquinoxalines, Polythiadiazole and poly (tetrazapyrene) is formed. Membrane according to claim 1, characterized in that in step B) a polymer containing recurring benzimidazole units of the formula

where n and m are an integer greater than or equal to 10, preferably greater than or equal to 100. Membrane according to claim 1, characterized in that in step C) a layer with a Thickness of 20 and 4000 μm, preferably between 30 and 3500 μm, in particular between 50 and 3000 μm is produced. Membrane according to claim 1, characterized in that the membrane formed after step D) a Thickness between 15 and 3000 μm, preferably between 20 and 2000 μm, in particular between 20 and 1500 μm Has. Electrode with a proton-conducting polymer coating Base of polyazoles available through a process comprising the steps A) Mixing one or more aromatic tetra-amino compounds with one or several aromatic carboxylic acids or their esters which contain at least two acid groups per carboxylic acid monomer, or mixing one or more aromatic and / or heteroaromatic diamino, in a mixture comprising vinyl-containing phosphonic acid and vinyl-containing sulfonic acid, forming a solution and / or dispersion B) Applying a layer using the mixture according to step A) on an electrode, C) heating the sheet / layer obtainable according to step B) under inert gas to temperatures of up to 350 ° C, preferably up to 280 ° C with formation of the polyazole polymer, D) polymerization the one in the flat Structures available according to step C) existing vinyl-containing phosphonic acid and vinyl-containing sulfonic acid. An electrode according to claim 19, the coating preferably having a thickness between 2 and 3000 μm between 3 and 2000 μm, in particular between 5 and 1500 μm Has. Membrane electrode unit containing at least one electrode and at least one membrane according to one or more of the claims 1 to 18. Membrane electrode unit containing at least one electrode according to claim 19 or 20 and at least one membrane according to one or more of claims 1 to 18th Fuel cell containing one or more membrane electrode assemblies according to claim 21 or 22.