EP1292632A2

EP1292632A2 - Ionically and covalently cross-linked polymers and polymer membranes

Info

Publication number: EP1292632A2
Application number: EP01960223A
Authority: EP
Inventors: Jochen Kerres; Wei Zhang; Chy-Ming Tang
Original assignee: Institut fuer Chemische Verfahrenstechnik Universitaet Stuttgart
Current assignee: HAERING, RIMA; HAERING, THOMAS
Priority date: 2000-05-19
Filing date: 2001-05-17
Publication date: 2003-03-19
Also published as: US20030208014A1; JP2015057484A; JP5661656B2; KR20030007583A; CA2407250C; DE10024576A1; WO2001087992A3; CA2407250A1; WO2001087992A2; CN1433442A; MY128567A; BR0110876A; JP2003533560A; AU2001281776A1; JP2012111950A; US6767585B2

Abstract

The present invention relates to ionically and covalently cross-linked polymers and polymer membranes having recurrent units of the general formula (1), wherein Q is a link, oxygen, sulfur, (2) or (3) and the R radical is a divalent radical of an aromatic or heteroaromatic compound, and which are characterized in that a) R radical comprises at least partially substituents of general formula (4A), (4B), (4C), (4D), (4E), (4F), (4G) and/or (4H), b) R radical comprises at least partially substituents of the general formula (5A) and/or (5B) and/or the R radical is at least partially a group of the general formula (5C) and/or (5D) and c) the R radical comprises at least partially bridges of the general formula (6) linking at least to R radicals together, R>1<, R>2<, R>3<, R>4<, R>5<, M, X, Y, Z and m having the herein-mentioned meanings.

Description

Covalently and ionically cross-linked polymers and polymer membranes

The present invention relates to covalently and ionically crosslinked polymers, in particular covalently and ionically crosslinked polymers having repeating units of the general formula

- Q-R—, CD where Q is a bond, oxygen, sulfur,

the radical R is a divalent radical of an aromatic or heteroaromatic compound. Furthermore, the present invention describes a method for producing the covalently and ionically crosslinked polymers and their use, in particular in fuel cells.

Polymers with repeating units of the general formula (1) are already known. They include, for example, polyarylenes such as polyphenylene and polypyrene, aiOmatische polyvinyl compounds such as polystyrene and polyvinyl pyridine, polyphenylene vinylene, aiOmatische polyethers such as polyphenylene oxide, aromatic polythioethers such as polyphenylene sulfide, polysulfones, such as Radel R ^®, and polyether ketones such as PEK. Furthermore, they also include polypyrroles, polythiophenes, polyazoles, such as polybenzimidazole, polyanilines, polyazulenes, polycarbazoles and polyindophenines.

Recently, the use of such polymers for the production of membranes for use in fuel cells has become increasingly important won. In particular, polymers with basic groups, such as sulfonic acid groups and amino groups, are increasingly described in the literature. The membranes are doped with concentrated phosphoric acid or sulfuric acid and serve as proton conductors in so-called polyelectrolyte membrane fuel cells (PEM fuel cells). Such membranes allow the membrane electrode assembly (MEE) to operate at higher temperatures and in this way significantly increase the tolerance of the catalyst to the carbon monoxide formed as a by-product during the reforming, so that gas processing or gas cleaning is considerably simplified. A disadvantage of these membranes is their mechanical instability with a low modulus of elasticity, a low tensile strength and a low upper flow limit, and their relatively high permeability to hydrogen, oxygen and methanol.

First approaches to solving these problems are disclosed in documents DE 196 22 337, WO 99/02755 and WO 99/02756. DE 196 22 337 describes a

Process for the preparation of covalently cross-linked ionomer membranes, which is based on an alkylation reaction of polymers containing sulfinate groups, polymer blends and polymer (blend) membranes. The covalent network has good resistance to hydrolysis even at higher temperatures. However, it is disadvantageous that the covalently crosslinked ionomers and ionomer membranes dry out easily because of the hydrophobic covalent network and can therefore become very brittle; they are therefore only of limited suitability for applications in fuel cells, in particular at higher temperatures.

WO 99/02756 and WO 99/02755 disclose ionically crosslinked acid-base polymer blends and polymer (blend) membranes. An advantage of the ionically crosslinked acid-base blend membranes is that the ionic bonds are flexible, the polymers / membranes do not dry out so easily even at higher temperatures because of the hydrophilicity of the acid-base groups, and therefore the polymers / membranes also do not become brittle at higher temperatures. However, the ionically crosslinked ionomer (membrane) systems described in these documents have the disadvantage that the ionic bonds are in the temperature range dissolve between 60 and 90 ° C and the polymers / membranes begin to swell exorbitantly from this temperature range. Therefore, these membranes are also not very suitable for applications in fuel cells, especially at higher temperatures above 80 ° C.

In view of the prior art, it is an object of the present invention to provide a crosslinked polymer with improved properties. The polymer according to the invention should have a low volume resistivity, preferably less than or equal to 100 Ωcm at 25 ° C., and a low permeability for hydrogen, oxygen and methanol.

In addition, it should have the best possible mechanical stability, in particular an improved modulus of elasticity, a higher tear strength and an improved swelling behavior. It should preferably swell by less than 100% in deionized water at a temperature of 90 ° C.

Another object was to provide a cross-linked polymer that can be used in fuel cells. In particular, the crosslinked polymer should be suitable for use in fuel cells above 80 ° C., in particular above 100 ° C.

The object of the invention was also to provide a process for producing the crosslinked polymer which can be carried out in a simple manner, inexpensively and on an industrial scale.

These and other tasks which are not explicitly mentioned, but which can easily be derived or inferred from the contexts discussed at the outset, are achieved by means of a covalently and ionically crosslinked polymer having all the features of patent claim 1 1 related subclaims placed under protection. Processes for producing the crosslinked polymer according to the invention are set out in the process claims described, while the claims of the use category protect preferred uses of a crosslinked polymer according to the invention.

The fact that a covalently and ionically crosslinked polymer having repeating units of the general formula (1) is available, which is characterized in that a) the radical R is at least partially substituents of the general formula (4A), (4B), (4C ), (4D), (4E), (4F), (4G) and / or (4H),

OM (4D)

- R ¹ - B _χ

OM

X (4H)

-R ¹ -

X wherein the radicals R ¹ independently of one another are a bond or a group having 1 to 40 carbon atoms, preferably a branched or unbranched alkyl, cycloalkyl or an optionally alkylated aryl group, M is hydrogen, a metal cation, preferably Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ , or an optionally alkylated ammonium ion and X is a halogen or an optionally alkylated amino group, b) the radical R at least partially has substituents of the general formula (5A) and / or (5B),

wherein R ² , R ³ , R ⁴ and R ^{5 are} independently a group having 1 to 40 carbon atoms, preferably a branched or unbranched alkyl, cycloalkyl or an optionally alkylated aryl group, at least two of the radicals R ² , R ³ and R ⁴ can be closed to form an optionally aromatic ring, and or the radical R is at least partially a group of the general formula (5C) and / or (5D)

and c) the radical R at least partially has bridges of the general formula (6), combine the at least two radicals R, where Y is a group having 1 to 40 carbon atoms, preferably a branched or unbranched alkyl, cycloalkyl or optionally alkylated aryl group, Z is hydroxyl, a group of the general formula

or a group with a molecular weight greater than 20 g / mol consisting of the optional components H, C, O, N, S, P and halogen atoms and m is an integer greater than or equal to 2, a crosslinked bond is not readily predictable To make polymer accessible with improved mechanical properties, in particular a higher modulus of elasticity, an improved tear strength and an improved swelling behavior.

At the same time, the crosslinked polymer according to the invention shows a number of further advantages. These include:

=> The doped plastic membranes have a low specific

Volume resistance, preferably less than or equal to 100 Ωcm at 25 ° C.

=> The doped plastic membranes have only a low permeability for hydrogen, oxygen and methanol.

=> Even have an extremely thin membrane of the crosslinked polymer according to the invention with a total thickness between 10 and 100 μ sufficiently good material properties at 80 ° C, especially a very high mechanical stability and a low permeability for hydrogen, oxygen and methanol.

=> The doped plastic membrane is suitable for use in fuel cells above 80 ° C, especially under normal pressure.

=> The doped plastic membrane is simple, large-scale and inexpensive to manufacture.

According to the present invention, the polymer is ionically and covalently cross-linked. According to the invention, crosslinked polymers refer to those polymers whose linear or branched macromolecules present in the collective are linked to one another to form three-dimensional polymeric networks. Networking can be done via the

Formation of covalent as well as the formation of ionic bonds. Further details can be found in the specialist literature, for example CD Rompp Chemie Lexicon - Version 1.0, Stuttgart / New York: Georg Thieme Verlag 1995, keyword "networking" and the literature cited here.

The crosslinked polymer according to the invention has recurring units of the general formula (1), in particular recurring units corresponding to the general formulas (1A), (1B), (IC), (1D), (1E), (1F), (IG), (IG), ( 1H), (II), (1J), (1K), (1L), (IM), (IN), (1O), (1P), (IQ), (1R), (IS) and / or ( IT), on:

-OR ⁶ - ^(1A)

(1B)

-S-R- (I

-O— R-SO ₂ -R— (1D)

-O— R ^ SOz-R— O— R— - OR ⁶ -SO ₂ -R ⁶ -OR ⁶ -R ⁶ - ^(1E)

- OR ⁶ -SO ₂ -R ⁶ -R ⁶ -SO ₂ -R ^ - ^(1G)

- OR-SO ₂ -R ⁶ -R ⁶ -SO ₂ -ROR-SO ₂ -R— ^(1H) with O <x, y <100% based on the number of all recurring units

- OR ⁶ -CO-R ⁶ - ^(U)

- O— R ⁶ -CO-R ⁶ -CO-R ⁶ - ^(1K)

- O- R ⁶ -CO-ROR ⁶ -CO-R-CO-R ^ - ^(1L)

- OR ⁶ -OR ⁶ -CO-R ⁶ - ^(1M)

- O- ROR-CO-R ⁶ -CO-R ⁶ - ^(1N)

it O <y <100%

(1P)

-R ^υ -

-R— CH = CH - (IQ)

-CHR ^! - CH ₂ - (1R)

N N (IS)

- <- ≠ - u

The radicals R ^{6 are,} independently of one another, the same or different 1, 2-phenylene, 1, 3-phenylene, 1,4-phenylene, 4,4'-biphenyl, a divalent radical of a heteroaromatic, a divalent radical of a C ₁₀ aromatic , a divalent radical of a C ₁₄ aromatic and / or a divalent pyrene radical. An example of a C ₁₀ aromatics is naphthalene, for a C ₁₄ aromatics phenanthrene. The substitution pattern of the aromatic and / or heteroaromatic is arbitrary, in the case of phenylene, for example, R ⁶ can be ortho, meta and para phenylene.

The radicals R ⁷ , R ⁸ and R ⁹ denote single-, four- or three-bonded aromatic or heteroaromatic groups and the radicals U, which are the same within a repeating unit, represent an oxygen atom, a sulfur atom or an amino group which is 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.

Particularly preferred in the present invention, polymers having recurring units of the general formula (1) belong to homopolymers and copolymers, for example random Copofymere as Victrex ^® 720 P and Astrel ^®. Very particularly preferred polymers are polyaryl ethers, polyaryl thioethers, polysulfones, polyether ketones, poly pyrroles, polythiophenes, polyazoles, polyphenylenes, polyphenylene vinylenes, polyanilines, polyazulenes, polycarbazoles, polypyrenes, polyindophenines and polyvinyl pyridines, in particular: polyaryl ethers:

polyphenylene oxide

Poly arylthioether:

polyphenylene sulfide

polysulfones:

^® Victrex 200 P

^ Victrex 720 P with n> o ®Radel

Radel R

Victrex HTA

Astrel with n <o

Udel

Polyether ketones: PEK

PEKK

(1K-1)

PEKEKK

PEEK

PEEKK

polypyrroles:

polythiophenes:

polyazoles:

polybenzimidazole

Polyphenylene:

Polyphenylenvmylen:

polyaniline:

polyazulene:

polycarbazole:

polypyrene:

Polyindophenine:

polyvinyl pyridine:

Cross-linked polymers with recurring units of the general formula (1A-1), (1B-1), (1C-1), (11-1), (1G-1), (1E-1), ( 1H-1), (11-1), (1F-1), (1 -1), (1K-1), (1L-1), (1M-1) and / or (1N-1). In the context of the present invention, n denotes the number of repeating units along a macromolecule chain of the crosslinked polymer. This number of repeating units of the general formula (1) along a macromolecule chain of the crosslinked polymer is preferably an integer greater than or equal to 10, in particular greater than or equal to 100. The number of repeating units of the general formula (1A), (1B), ( IC), (1D), (1E), (IF), (IG), (IH), (II), (IJ), (IK), (IL), (IM), (IN), (10) , (IP), (IQ), (IR), (IS) and / or (IT) along a macromolecule chain of the crosslinked polymer an integer greater than or equal to 10, in particular greater than or equal to 100.

In a particularly preferred embodiment of the present invention, the number average molecular weight of the macromolecule chain is greater than 25,000 g / mol, advantageously greater than 50,000 g / mol, in particular greater than 100,000 g / mol.

The cross-linked polymer according to the invention can in principle also have different repeating units along a macromolecule chain. However, it preferably has only the same repeating units of the general formula (1A), (1B), (IC), (1D), (1E), (IF), (IG), (IH), (II) along a macromolecule chain, (IJ), (IK), (IL), (IM), (IN), (10), (IP), (IQ), (IR), (IS) and / or (IT).

In the context of the present invention, the radical R preferably has at least partially substituents of the general formula (4A), (4B), (4C), (4D), (4E), (4F), (4G) and / or (4H) of the general formula (4A), (4B), (4C) and / or (4D), advantageously of the general formula (4A), (4B) and / or (4C), in particular of the general formula (4A):

OM (4D)

-R, ι ¹ - B. \,

OM

The radicals R ¹ independently denote a bond or a group having 1 to 40 carbon atoms, preferably a branched or unbranched alkyl, cycloalkyl or an optionally alkylated aryl group. In the context of a very particularly preferred embodiment of the present invention, R ^{1 is} a bond.

M represents hydrogen, a metal cation, preferably Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ , or an optionally alkylated ammonium ion, advantageously hydrogen or Li ⁺ , in particular hydrogen.

X is a halogen or an optionally alkylated amino group. Furthermore, the radical R according to the invention has at least partially substituents of the general formula (5A) and / or (5B), preferably (5A),

and / or the radical R is at least partially a group of the general formula (5C) and / or (5D), preferably (5C).

In this context, the radicals R ² , R ³ , R ⁴ and R ⁵ independently of one another denote a group having 1 to 40 carbon atoms, preferably a branched or unbranched alkyl, cycloalkyl or an optionally alkylated aryl group, at least two of the radicals R ² , R ³ and R ⁴ can be closed to form an optionally aromatic ring.

Particularly advantageous effects can be achieved if R at least partially has substituents of the general formula (5A-1) and / or (5A-2).

O ( ^5A -

_JL _R ιo

The radicals R ^{10 here} denotes an optionally alkylated aryl group which has at least one optionally alkylated amino group, or an optionally alkylated heteroaioate which either has at least one optionally alkylated amino group or has at least one nitrogen atom in the heteroaiomatic core. R ¹¹ is hydrogen, an alkyl, a cycloalkyl, an aryl or a heteroaryl group or a radical R ¹⁰ with the abovementioned meaning, where R ¹⁰ and R ^{11 can be} identical or different.

Substituents of the formula (5A-1) in which R ^{10 is} an optionally alkylated aniline residue or pyridine residue, preferably an alkylated aniline residue, are very particularly preferred according to the invention. Furthermore, substituents of the formula (5A-2) in which R ¹⁰ and R ^{11 are} optionally alkylated aniline residues or pyridine residues, preferably alkylated aniline residues, are also particularly preferred.

In the context of the present invention, the radical R at least partially has brackets of the general formula (6)

combine the at least two radicals R, where Y is a group having 1 to 40 carbon atoms, preferably a branched or unbranched alkyl, cycloalkyl or optionally alkylated aryl group, advantageously a linear or branched alkyl group having 1 to 6 carbon atoms.

Z denotes hydroxyl, a group of the general formula

or a group with a molecular weight greater than 20 g / mol consisting of the optional components H, C, O, N, S, P and halogen atoms, and m represents an integer greater than or equal to 2, preferably 2.

The crosslinked polymer according to the invention is preferably doped with acid. In the context of the present invention, doped polymers refer to those polymers which, owing to the presence of doping agents, have an increased proton conductivity in comparison with the undoped polymers. Dopants for the polymers according to the invention are acids. In this context, acids include all known Lewis and Bransted acids, preferably inorganic Lewis and Bransted acids. It is also possible to use polyacids, especially isopolyacids and heteropolyacids, and mixtures of different acids. For the purposes of the present invention, heteropolyacids denote inorganic polyacids with at least two different central atoms, each of which consists of weak, polybasic oxygen acids of a metal (preferably Cr, Mo, V, W) and a non-metal (preferably As, I, P, Se, Si, Te) arise as partially mixed anhydrides. They include, among others, 12-molybdate phosphoric acid and 12-tungsten phosphoric acid.

Dopants which are particularly preferred according to the invention are sulfuric acid and phosphoric acid. A very particularly preferred dopant is phosphoric acid (H ₃ PO ₄ ).

The conductivity of the invention can be determined by the degree of doping

Plastic membrane are affected. The conductivity increases with increasing dopant concentration until a maximum value is reached. According to the invention, the degree of doping is stated as mole of acid per mole of repeating unit of the polymer. In the context of the present invention, a degree of doping between 3 and 15, in particular between 6 and 12, is preferred. Processes for producing doped plastic membranes are known. In a preferred embodiment of the present invention, they are obtained by a polymer according to the invention for a suitable time, preferably 0.5-96 hours, particularly preferably 1-72 hours, at temperatures between room temperature and 100 ° C. and, if appropriate, increased pressure with concentrated acid , preferably wetted with highly concentrated phosphoric acid.

The spectrum of properties of the crosslinked polymer according to the invention can be changed by varying its ion exchange capacity. The ion exchange capacity is preferably between 0.5 meq / g and 1.9 meq / g, in each case based on the total mass of the polymer.

The polymer according to the invention has a low volume resistivity, preferably of at most 100 Ωcm, expediently of at most 50 Ωcm, in particular of at most 20 Ωcm, in each case at 25 ° C.

The properties of the plastic membrane according to the invention can be controlled in part by their overall thickness. However, even extremely thin plastic membranes already have very good mechanical properties and a lower permeability for hydrogen, oxygen and methanol. They are therefore suitable for use in fuel cells above 80 ° C., expediently above 100 ° C., in particular for use in fuel cells above 120 ° C., without the edge region of the membrane electrode unit having to be reinforced. The total thickness of the doped plastic membrane according to the invention is preferably between 5 and 100 μm, advantageously between 10 and 90 μm, in particular between 20 and 80 μm.

In a very particularly preferred embodiment of the present invention, it swells at a temperature of 90 ° C. in deionized water by less than 100%. Methods for producing the crosslinked polymer according to the invention are obvious to the person skilled in the art. However, within the scope of the present invention, a procedure has proven to be very particularly suitable in which one or more reactant polymers, the one or more or all of the functional groups a), b) and d) have, where d) sulfinate groups of the general formula (6)

O. (6)

- R i ¹ - S II— OM with a compound of the general formula (7) YL, ». (?) where L is a leaving group, preferably an F, Cl, Br, I, tosylate, and n is an integer greater than or equal to 2, preferably 2. Each reactant polymer preferably has recurring units of the general formula (1). Furthermore, it is expediently not covalently crosslinked.

In the event that the radical R in at least one reactant polymer has at least partially substituents of the general formula (5A) or is at least partially a group of the general formula (5C), the reaction with the compound (7) can also be used to form bridges of the general formula (8) and / or (9).

The formation of bridges between different substituents of the general formula (5A) or between different groups of the general formula (5C) is also conceivable. In the context of a particularly preferred embodiment of the present invention, a polymer mixture is made

1) at least one starting polymer having functional groups a),

2) at least one reactant polymer having functional groups b) and 3) at least one reactant polymer having functional groups d) are used.

In the context of a further particularly preferred embodiment of the present invention, a polymer mixture of 1) at least one starting polymer having functional groups a) and b) and 2) at least one starting polymer having functional groups d) is used.

According to another particularly preferred embodiment of the present invention, it can also be particularly advantageous to use a polymer mixture

1) at least one starting polymer having functional groups a) and d) and

2) to use at least one starting polymer having functional groups b).

Furthermore, there is also a process in which a polymer mixture is prepared

1) at least one starting polymer having functional groups a) and

2) uses at least one starting polymer having functional groups b) and d), a particularly preferred embodiment of the present invention.

According to the invention, it can also be extremely expedient to use at least one polymer having functional groups of the general formulas a), b) and d).

The reactant polymer (s) to be used according to the invention can in principle have different repeating units of the general formula (1). However, they preferably have only the same repeating units of the general formula (1A), (1B), (IC), (1D), (1E), (IF), (IG), (IH), (II), (IJ) , (IK), (IL), (IM), (IN), (10), (IP), (IQ), (IR), (IS) and / or (IT). The number of repeating units of the general formula (1A), (1B), (IC), (1D), (1E), (IF), (IG), (IH), (II), (IJ), (IK ), (IL), (IM), (IN), (10), (IP), (IQ), (IR), (IS) and / or (IT) is preferably an integer greater than or equal to 10, preferably at least 100 recurring units.

In a particularly preferred embodiment of the present invention, the number average of the molecular weight of the starting polymer or polymers is greater than 25,000 g / mol, advantageously greater than 50,000 g / mol, in particular greater than 100,000 g / mol.

The synthesis of the starting polymer having functional groups of the general formulas a), b) and or d) is already known. It can be carried out, for example, by reacting a polymer of the general formula (1) with n-butyllithium in a dried aprotic solvent, preferably tetrahydrofuran (THF), under an inert gas atmosphere, preferably argon, and lithiating in this way.

To introduce the functional groups, the lithiated polymer is in a manner known per se with suitable functionalizing agents, preferably with alkylating agents of the general formula

L— Subst.> 0 °) where Subst. Is the substituent to be introduced, with ketones and / or aldehydes, which are converted to the corresponding alcoholates, and / or with carboxylic acid residues and / or carboxylic acid halides, which are converted to the corresponding ketones. Sulfonate groups can also be introduced by reacting the lithiated polymer with SO ₃ , and sulfonate groups can also be introduced by reacting the lithiated polymer with SO ₂ .

By successive implementation with several different functionalization agents, polymers are obtained which have at least two different substituents. For further details, reference is made to the state of the art, in particular to the publications US 4,833,219, J. Kerres, W. Cui, S. Reichle; New sulfonated engineering polymres via the melation route. 1. Sulfonated poly (ethersulfone) PSU Udel ^® viametalation-sulfinate ion-oxidation "J. Polym Be .: Part A:. Polym Chem 34, 2421-2438 (1996), WO 00/09588 Al veiwiesen on whose Offenbaning herewith.. explicit reference is made.

The degree of functionalization of the starting polymer is preferably in the range from 0.1 to 3 groups per repeating unit, preferably between 0.2 and 2.2 groups per repeating unit. Starting polymers with 0.2 to 0.8 groups a), preferably sulfonate groups, per repeat unit are particularly preferred. Furthermore, reactant polymers with 0.8 to 2.2 groups b) per repeat unit have proven particularly useful. In addition, particularly advantageous results are achieved with starting polymers which have 0.8 to 1.3 groups d) per repeating unit.

In the context of the present invention, it has proven to be particularly expedient to dissolve one or the starting polymers in a dipolar aprotic solvent, preferably in N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyiTolidone, dimethyl sulfoxide or sulfolane and react with the halogen compound with stirring.

Particularly advantageous results can be achieved if a) the polymer solution is spread as a film on a base, preferably on a glass plate, a fabric or a nonwoven, and b) the solvent, if appropriate at elevated temperature above 25 ° C. and / or reduced pressure evaporates less than 1000 mbar and in this way receives a polymer membrane.

The properties of the polymer according to the invention can also be improved by changing the polymer a) treated with an acid in a first step and b) treated with deionized water in a further step. wherein the polymer is optionally treated with an alkali before the first step.

Possible areas of use for the covalently and ionically crosslinked polymer according to the invention are obvious to the person skilled in the art. It is particularly suitable for all applications which are drawn for cross-linked polymers with low volume resistivities, preferably less than 100 Ωcm at 25 ° C. Because of their characteristic properties, they are particularly suitable for applications in electrochemical cells, preferably in secondary batteries,

Electrolysis cells and in polymer electrolyte membrane fuel cells, in particular in hydrogen and direct methanol fuel cells.

Furthermore, they can also be used in a particularly advantageous manner in membrane separation processes, preferably in gas separation, pervaporation, perstraction, reverse osmosis, nanofiltration, electrodialysis and diffusion dialysis.

The invention is explained in more detail below by means of examples and comparative examples, without the teaching of the invention being restricted to these examples. The specified property values, as well as the values described above, were determined as follows:

To determine the ion exchange capacity IEC, a piece of protonated ionomer membrane was dried to constant weight. 1 mg of the membrane was placed in about 50 ml of saturated NaCl solution. This resulted in an exchange of ions in the sulfonate groups, and the FT ions passed into the saturated solution. The solution was stirred or shaken with the membrane for about 24 hours. Then 2 drops of the indicator bromothymol blue were added to the solution and titrated with 0.1 normal NaOH solution until the color changed yellow / blue. The IEC was calculated as follows: IEC [meq / g] = (normality NaOH [meq / ml] * consumption NaOH [ml] * factor NaOH) / mass membrane [g]

The specific volume resistance R ^{sp of} the membranes was determined by means of impedance spectroscopy (IM6 impedance measuring device, Zahner electrics) in a plexiglass unit with gold-coated copper electrodes (electrode area 0.25 cm ² ). According to the invention, the impedance at which the phase angle between current and voltage was 0 denotes the specific volume resistance. The specific measuring conditions were as follows: 0.5 N HC1 was used, the membrane to be measured was packed between two Nafion 117 membranes, the multi-layer arrangement Nafion 117 / membrane / Nafion 117 membrane was pressed between the two electrodes. In this way, the interface resistances between the membrane and the electrode were eliminated by first measuring the multilayer arrangement of all 3 membranes and then the two Nafion 117 membranes alone. The impedance of the Nafion membranes was subtracted from the impedance of all 3 membranes. In the context of the present invention, the specific volume resistances at 25 ° C were determined.

To determine the swelling, the membranes were equilibrated in deionized water at the respective temperature and then weighed (= _m ^εe ι ^UoUei1 ). The membranes were then dried in a drying cabinet at elevated temperature and weighed again (= rri ^rockea ). The degree of swelling is calculated as follows:

dry λ l - dry

a.) Polymers used a-l) PSU Udel®:

PSU P 1800 (Amoco) a-2) PEK-SO ₃ Li:

Lithium salt of sulfonated polyether ketone PEK;

production:

100 g PEK-SO ₃ H with an ion exchange capacity of 1.8 meq SO ₃ H / g polymer were stirred in 1000 ml of a 10% by weight aqueous LiOH solution for 24 hours. Thereafter, the Li-exchanged PEK-SO ₃ Li was filtered off, washed with water until the wash water became neutral and then dried at 100 ° C. for 48 h. The resulting polymer contained 0.4 SO ₃ Li units per repeat unit (ion exchange capacity (IEC) of the protonated form = 1.8 meq Sθ3H / g).

a-3) PSU-S02Li:

Lithium salt of sulfinated polyether sulfone PSU Udel ^s

obtained according to US 4,833,219 or J. Ken-es, W. Cui, S. Reichle; New sulfonated engineering polymres via the melation route. 1. Sulfonated poly (ethersulfone) PSU Udel ^® via metalation-sulfinate ion-oxidation "J. Polym Be .: Part A:... Polym Chem 34, 2421-2438 (1996) IEC = 1.95 meq the protonated form Sθ2Li / G a-4) PSU-DPK:

obtained by reacting 2,2'-dipyridyl ketone with lithiated PSU Udel

(according to WO 00/09588 AI); one 2,2'-dipyridyl ketone unit per repeat unit

a-5) Synthesis of PSU-P3-SO ₂ Li, PSU-EBD-SO ₂ Li

PSU-P3-SO ₂ Li,

PSU-EBD-SO i

PSU Udel ^{® was first dissolved} in dry THF and cooled to -75 ° C under argon. Traces of water in the reaction mixture were removed with 2.5 M n-butyllithium (n-BuLi). Then the dissolved polymer lithiated with 10 M n-BuLi. The reaction was allowed to react for one hour and then pyridine-3-aldehyde or 4,4'-bis (N, N-diethylamino) benzophenone was added. The reaction temperature was then raised to -20 ° C for one hour. For the reaction with SO ₂ , the mixture was then cooled again to -75 ° C. and the SO _{2 was} introduced.

For working up, 10 ml of an isopropanol / water mixture were injected into the reaction solution, warmed to room temperature, the polymer was precipitated in an excess of isopropanol, the resulting polymer was filtered off and, if appropriate, washed with isopropanol. For purification, the polymer was slurried in methanol and filtered off again. The polymer was dried in vacuo, preferably at 80 ° C. The degrees of substitution were obtained by quantitative evaluation of the 'H-NMR spectra.

b.) Membrane production

The polymers PEK-SO ₃ Li, PSU-P3-SO ₂ Li, PSU-EBD-SO ₂ Li, PSU-DPK and / or PSUSθ2Li were dissolved in NMP according to Table 2 and filtered. The polymer solution was then degassed in vacuo and 1,4-diiodobutane was then added.

After that, it was poured onto a glass plate and knife out. The glass plate was dried in an oven at 60 ° C for one hour, then at 90 ° C for another hour and finally at 120 ° C under vacuum overnight. The plate was cooled to room temperature and placed in a water bath. The membrane was separated from the glass plate and stored in 10% HC1 at 90 ° C for one day in the oven. It was then conditioned in deionized water at 60 ° C.

c.) Characterization of the membranes

The characteristics of the membranes are summarized in Tables 2 and 3. The theoretical ion exchange capacity IEC ^theo was calculated taking into account both ionic and covalent crosslinking. It can be seen from Table 3 that the covalently and ionically crosslinked membranes have significantly lower swelling values than the purely ionically crosslinked membranes, even at temperatures of 90 ° C.

Table 2: Membrane data

IEC ^exp : experimentally determined ion exchange capacity R ^sp : specific volume resistance

Table 3: Swelling behavior of the membranes in water depending on the temperature

Claims

Patentanspräche:

1. Covalently and ionically crosslinked polymer having repeating units of the general formula

- Q-R—, (1) where Q is a bond, oxygen, sulfur,

the radical R is a divalent radical of an aromatic or hetero-aromatic

Compound is characterized in that a) the radical R is at least partially substituents of the general formula (4A), (4B), (4C), (4D), (4E), (4F), (4G) and or or (4H) having,

where the radicals R ^{1 are,} independently of one another, a bond or a group having 1 to 40 carbon atoms, preferably a branched or unbranched alkyl, cycloalkyl or an optionally alkylated aryl group,

M is hydrogen, a metal cation, preferably Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ , or an optionally alkylated ammonium ion and X is a halogen or an optionally alkylated amino group, the radical R is at least partially substituents of the general formula (5A ) and / or (5B),

wherein R ² , R ³ , R ⁴ and R ⁵ independently of one another a 1 to 40

Group having carbon atoms, preferably a branched or unbranched alkyl, cycloalkyl or an optionally alkylated aryl group, where at least two of the radicals R ² , R ³ and R ⁴ can be closed to form an optionally aromatic ring, and / or the radical R is at least partially a group of the general formula (5C) and or (5D) and c) the radical R at least partially has brackets of the general formula (6),

combine the at least two radicals R, where Y is a group having 1 to 40 carbon atoms, preferably a branched or unbranched alkyl, cycloalkyl or optionally alkylated aryl group, Z is hydroxyl, a group of the general formula

or a group with a molecular weight greater than 20 g / mol consisting of the optional components H, C, O, N, S, P and halogen atoms and m is an integer greater than or equal to 2.

2. Polymer according to claim 1, characterized in that the repeating units of the general formula (1) units corresponding to the general formulas (1A), (IB), (IC), (ID), (1E), (IF), ( IG), (IH), (II), (IJ), (IK), (IL), (IM), (IN), (10), (IP), (IQ), (IR), (IS) and / or (IT),

-OK ⁶ - ^<1A)

-SR ⁶ - ^<1B) - OR ⁶ -SO ₂ -R ^ - ^(1Q

- OR ⁶ -SO ₂ -R ^ OR ⁶ - ^(1D)

- OR ⁶ -SO ₂ -R ⁶ -OR ⁶ -R ⁶ - ^(1E)

- OR ⁶ -SO ₂ -R ⁶ -R-SO ₂ -R ⁶ - ^(1G)

- OR ⁶ -SO ₂ -RR-SO ₂ -R ⁶ -OR-SO ₂ -R ⁶ - ^(1H)

- oR ⁶ -SO ₂ -R ⁶ - - x fS0 ₂ -RR ⁶ -iy ^(1I)

with O <x, y <100% based on the number of all recurring units

- OR-CO-R ⁶ - ^(U)

(1K)

-O— R-CO-R-CO- -R ^D -

(IL)

-O- R-CO-ROR-CO-R-CO-R ⁶ -

-OR ⁶ -OR ⁶ -CO-R ⁶ - ^(1M)

-O- R ⁶ -OR-CO-R ⁶ -CO-R ⁶ - ^(1N)

it O <y <100%

^(1P)(1P)

- R-CH = CH— ^(1Q)

- CHR ^ CH, - ^(1R) NN (IS)

_ _< v_ _R _

V V

in which the radicals R ^6, independently of one another, are identical or different 1, 2-phenylene, 1,3-phenylene, 1,4-phenylene, 4,4'-biphenyl, a divalent radical of a heteroaromatic, a divalent radical of a C ₁₀ aromatic, are a divalent radical of a C ₁₄ aromatics and / or a divalent pyrene radical, the radicals R ⁷ , R ⁸ and R ^{9 are} mono-, di- or tri-bonded aromatic or heteroaromatic groups, and the radicals U which are within a Repeating unit are the same, an oxygen atom, a sulfur atom or an amino group which carries a hydrogen atom, a 1-20 carbon atom-containing group, preferably a branched or unbranched alkyl or alkoxy group, or an aryl group as a further radical.

3. Polymer according to claim 1 or 2, characterized in that it is doped with acid.

4. Polymer according to any one of the preceding claims, characterized in that it has a volume resistivity of at most 100 Ωcm at 25 ° C.

5. Polymer according to one of the preceding claims, characterized in that it is at a temperature of 90 ° C in deionized water by less than

100% swells.

6. Polymer according to one of the preceding claims, characterized in that it has an ion exchange capacity between 0.5 meq / g and 1.9 meq / g, in each case based on the total mass of the polymer.

7. A process for the preparation of a polymer according to any one of the preceding claims, characterized in that one or more starting polymers, the one or more or all of the functional groups a), b) and d), wherein a) and b) according to Claim 1 are defined and d) denotes sulfinate groups of the general formula (6)

O> ( ⁶ )

- R ¹ - S— OM with a compound of general formula (7)

where L is a leaving group and n is an integer greater than or equal to 2.

8. The method according to claim 7, characterized in that a polymer mixture

1) at least one starting polymer having functional groups a),

2) at least one starting polymer having functional groups b) and

3) uses at least one starting polymer having functional groups d).

9. The method according to claim 7, characterized in that one

1) at least one starting polymer having functional groups a) and b) and

2) uses at least one starting polymer having functional groups d).

10. The method according to claim 7, characterized in that one

1) at least one starting polymer having functional groups a) and d) and

2) uses at least one starting polymer having functional groups b).

11. The method according to claim 7, characterized in that one

1) at least one starting polymer having functional groups a) and

2) at least one starting polymer having functional groups b) and d) starts.

12. The method according to claim 7, characterized in that one uses at least one polymer having functional groups of the general formulas a), b) and d).

13. The method according to at least one of claims 7-12, characterized in that one or the starting polymers in a polar aprotic solvent, preferably in N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyιolidone, dimethyl sulfoxide or Sulfolan, dissolves and reacts with the halogen compound with stirring.

14. The method according to claim 13, characterized in that a) the polymer solution is spread as a film on a base and b) the solvent is evaporated, if appropriate at an elevated temperature of more than 25 ° C. and / or a reduced pressure of less than 1000 mbar, and in this way a polymer membrane receives.

15. The method according to at least one of claims 7 to 14, characterized in that the polymer is treated a) in a first step with an acid and b) in a further step with deionized water, the polymer optionally being treated before the first step treated with a lye.

16. The method according to at least one of claims 7 to 15, characterized in that the polymer is doped with an acid, preferably with phosphoric acid.

17. Use of the polymer according to at least one of claims 1 to 6 in electrochemical cells, preferably in secondary batteries, electrolysis cells and in polymer electrolyte membrane fuel cells, in particular in hydrogen and direct methanol fuel cells.

8. Use of the polymer according to at least one of claims 1 to 6 in membrane separation processes, preferably in gas separation, pervaporation, perstraction, reverse osmosis, nanofiltration, electrodialysis and diffusion dialysis.