JP2006045512A - Polymer electrolyte membrane and fuel cell using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polymer electrolyte membrane having excellent mechanical properties. <P>SOLUTION: (1) The polymer electrolyte membrane has an elastic modulus of 400-900 MPa at 23°C and a relative humidity of 50%, wherein all of its polymers as a constituent have an aromatic ring in its main chain, at least one type has an aliphatic chain in its main chain, and at least one type is a polymer electrolyte. (2) The polymer electrolyte membrane (1) has an ion-exchange capacity of 0.2-4 meq/g. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a polymer electrolyte membrane, and more particularly to a polymer electrolyte membrane having a specific elastic modulus.

  In recent years, various attempts have been made to search for an energy source having a low environmental load. Among them, fuel cells, particularly solid polymer electrolyte fuel cells using a solid polymer electrolyte membrane, are expected to be applied as a power source for automobiles and the like because of the advantage that the emission material is only water.

  As a polymer electrolyte membrane for such a solid polymer electrolyte fuel cell, there is a membrane obtained from a polymer electrolyte such as perfluoroalkyl sulfonic acid represented by Nafion (registered trademark of DuPont), but it is very expensive. However, problems such as low heat resistance, low film strength, and impracticality without some reinforcement have been pointed out.

  On the other hand, development of inexpensive polymer electrolytes that can replace the polymer electrolytes has recently been activated. Among them, a polymer with sulfonic acid groups introduced into an aromatic polyether with excellent heat resistance and high film strength, that is, an aromatic polymer with a sulfonic acid group in the side chain and an aromatic main chain is promising. For example, a sulfonated polyether ketone system (Patent Document 1) and a sulfonated polyethersulfone system (Patent Documents 2 and 3) have been proposed.

  By the way, the polymer electrolyte membrane is sandwiched between a separator, a gasket, a gas diffusion layer, and the like in the fuel cell stack, and a high surface pressure is applied. Under these conditions, the amount of water absorption of the membrane changes as the current changes and starts / stops, causing a dimensional change. As one of the required characteristics of the polymer electrolyte membrane for fuel cells, it is accompanied by water absorption / drying. The durability against expansion / contraction is high.

For this reason, polymer electrolyte membranes with improved mechanical properties have been proposed. For example, a film having a modulus of elasticity of 2400 to 5400 MPa obtained by adding polyethylene glycol or a derivative thereof to sulfonated polyarylene (Patent Document 4), a sulfonated polyarylene film, and tetrafluoroethylene are used to improve film folding resistance. A composite film (Patent Document 5) having an elastic modulus of 3300 to 5400 MPa obtained by laminating a copolymer film, and a film (Patent Documents 5 and 6) having an elastic modulus of 170 to 270 MPa and 350 MPa made of a fluorine-containing copolymer. Proposed.
However, these polymer electrolyte membranes have a problem that the mechanical durability in the fuel cell stack is still insufficient.

Japanese National Patent Publication No. 11-502249 Japanese Patent Laid-Open No. 10-45913 Japanese Patent Laid-Open No. 10-21944 JP 2002-008440 A JP 2002-008447 A Japanese Patent Laid-Open No. 11-329062

  As a result of intensive studies to find a polymer electrolyte membrane having superior mechanical properties, the inventor has developed a specific polymer having a specific elastic modulus of 400 MPa to 900 MPa at 23 ° C. and 50% relative humidity. The present inventors have found that the electrolyte membrane exhibits excellent mechanical durability even in the fuel cell stack and the like, thereby completing the present invention.

That is, the present invention
[1] Elastic modulus is 400 to 900 MPa at 23 ° C. and 50% relative humidity, and all of the polymers as constituents have an aromatic ring in the main chain, and at least one kind is a fat in the main chain. The present invention provides a polymer electrolyte membrane having a family chain and at least one polymer electrolyte.

Furthermore, the present invention provides
[2] The polymer electrolyte membrane according to the above [1], wherein the polymer electrolyte membrane has an ion exchange capacity of 0.2 to 4 meq / g.

The present invention also provides:
[3] The polymer electrolyte has, as a repeating unit, at least a unit represented by the following general formula (1) or a unit represented by the following general formula (2) and a unit represented by the following general formula (3). The polymer electrolyte membrane according to the above [1] or [2] is characterized by comprising at least.
— [(Ar ¹ ) _n —R ¹ — (Ar ² ) _m —X ¹ ] — (1)
(In the formula, R ¹ has an optionally substituted alkylene group having 2 to 10 carbon atoms, an optionally substituted oxyalkylene group having 2 to 10 carbon atoms, and a substituent. Represents a group selected from oxyalkyleneoxy groups having 2 to 10 carbon atoms, and Ar ¹ and Ar ² may each independently have a phenylene group or a substituent which may have a substituent. Represents a group selected from a good biphenylylene group, an optionally substituted triphenylene group, and an optionally substituted naphthylene group, and at least ^{one of} R ¹ , Ar ¹ , and Ar ² is ion-exchangeable X ¹ represents a direct bond, —O—, —S—, —CO—, —SO—, —SO ₂ —, n and m each represents 0 or 1, and n + m represents 1 Or 2.
— [(Ar ³ ) _o —R ² — (Ar ⁴ ) _p —X ² ] — (2)
^{- (Ar 5 -Z 1 -Ar 6} -Z 2) - (3)
(In the formula, R ² has an optionally substituted alkylene group having 2 to 10 carbon atoms, an optionally substituted oxyalkylene group having 2 to 10 carbon atoms, and a substituent. Represents a group selected from oxyalkyleneoxy groups having 2 to 10 carbon atoms, and Ar ³ , Ar ⁴ , Ar ⁵ , Ar ⁶ are each independently a phenylene group or a substituent which may have a substituent. Represents a group selected from a biphenylylene group which may have a substituent, a triphenylene group which may have a substituent, and a naphthylene group which may have a substituent, and at least one of Ar ⁵ and Ar ⁶ is X ² , Z ¹ and Z ² each independently represent a direct bond, —O—, —S—, —CO—, —SO— or —SO ₂ —, and o , P each independently represents 0 or 1.)

The present invention also provides:
[4] The polymer electrolyte of [3] above, wherein the ion-exchange group is an acid group selected from —SO ₃ H, —PO (OH) ₂ , —COOH, and —SO ₂ NHSO ₂ —. A membrane is provided.

The present invention also provides:
[5] The polymer electrolyte membrane according to any one of [1] to [4], wherein the main chain in the polymer electrolyte is a block copolymer composed of an aromatic segment and an aliphatic segment. To do.
[6] As a repeating unit, a polymer nonelectrolyte having at least a unit represented by the following general formula (4) is contained, or a unit represented by the following general formula (5) and a unit represented by the following general formula (6) The polymer electrolyte membrane according to any one of the above [1] to [5] is provided.
— [(Ar ⁷ ) _q —R ³ — (Ar ⁸ ) _r —X ³ ] — (4)
(In the formula, R ³ has an optionally substituted alkylene group having 2 to 10 carbon atoms, an optionally substituted oxyalkylene group having 2 to 10 carbon atoms, and a substituent. Represents a group selected from oxyalkyleneoxy groups having 2 to 10 carbon atoms, and Ar ⁷ and Ar ⁸ may each independently have a phenylene group or a substituent which may have a substituent. X ³ represents a group selected from a good biphenylylene group, an optionally substituted triphenylene group, and an optionally substituted naphthylene group, X ³ represents a direct bond, —O—, —S—, —CO. Represents-, -SO-, or -SO _2- , q and r each represents 0 or 1, and q + r represents 1 or 2;
)
-(R ⁴ -X ⁴ )-(5)
-(Ar ⁹ -Z ³ -Ar ¹⁰ -Z ⁴ )-(6)
(In the formula, R ⁴ has an optionally substituted alkylene group having 2 to 10 carbon atoms, an optionally substituted oxyalkylene group having 2 to 10 carbon atoms, and a substituent. Represents a group selected from oxyalkyleneoxy groups having 2 to 10 carbon atoms, and Ar ⁹ and Ar ¹⁰ may independently have a phenylene group or a substituent which may have a substituent. Represents a group selected from a good biphenylylene group, a triphenylene group which may have a substituent, and a naphthylene group which may have a substituent, and X ⁴ , Z ³ and Z ⁴ are each independently a direct bond, It represents any of —O—, —S—, —CO—, —SO—, and —SO ₂ —.)
[7] The polymer electrolyte membrane of [6] above, wherein the polymer non-electrolyte is a block copolymer.
In addition, the present invention provides:
[8] A fuel cell comprising the polymer electrolyte membrane according to any one of [1] to [7] is provided.

  The polymer electrolyte membrane of the present invention has an elastic modulus of 400 MPa to 900 MPa at a temperature of 23 ° C. and a relative humidity of 50%, and the polymer as a constituent component has an aromatic ring in its main chain, and at least one kind Has an aliphatic chain in its main chain and at least one is a polyelectrolyte, and therefore exhibits excellent mechanical durability.

Hereinafter, the present invention will be described in detail.
The polymer electrolyte membrane in the present invention is characterized in that the elastic modulus at 23 ° C. and 50% relative humidity is 400 MPa to 900 MPa. If the elastic modulus is too low, the membrane may creep in the fuel cell stack, and is preferably 500 MPa or more, more preferably 550 MPa or more, and particularly preferably 600 MPa or more. On the other hand, if the elastic modulus is too high, the brittleness of the film increases, and it is preferably 870 MPa or less, more preferably 840 MPa or less, and particularly preferably 800 MPa or less.

In the polymer electrolyte membrane of the present invention, in the polymer as a constituent component, all have an aromatic ring in the main chain, at least one kind has an aliphatic chain in the main chain, and at least one kind It is a polymer electrolyte. The polymer as a constituent component may be a polymer electrolyte or a mixture of a polymer electrolyte and a polymer that is not an electrolyte (hereinafter abbreviated as a polymer non-electrolyte).
In the present invention, all of these polymer electrolytes and polymer non-electrolytes have an aromatic ring in the main chain, and at least one of them has an aliphatic chain in the main chain. The polymer electrolyte main chain preferably has both an aromatic ring and an aliphatic chain, and in particular, the main chain is preferably a block copolymer of an aromatic segment and an aliphatic segment. Here, when a polymer electrolyte and / or a polymer non-electrolyte that does not have an aromatic ring in the main chain are included in the constituent components, the glass transition temperature of the polymer electrolyte membrane is low and the heat resistance is poor. , The water resistance of the film tends to decrease, which is not preferable.

The molecular weight of these polymer electrolytes and polymer non-electrolytes is usually about 1,000 to 1,000,000, expressed in terms of polystyrene-reduced number average molecular weight by the GPC method.
Here, when the number average molecular weight is less than 1000, the film strength tends to decrease, preferably 5000 or more, more preferably 20000 or more. On the other hand, if the number average molecular weight is larger than 1,000,000, it takes a long time to dissolve in the solvent or the solution viscosity becomes too high, and the film forming process tends to be difficult, preferably 500,000 or less, more preferably 300,000 or less. is there.

As also polyelectrolyte, as the ion exchange group, for _{example, -SO 3 H, -COOH, -PO} (OH) 2, -P (OH) 2, -SO 2 NHSO 2 -, - Ph (OH) ( Ph cation exchange groups such as a phenylene _{group), -NH 2, -NHR, -NRR} ', - NRR'R''+, -NH 3 + etc. (R, R', R '' is alkyl And a polymer having an anion exchange group such as a cycloalkyl group and an aryl group. Such an ion-exchange group may be directly introduced into the aromatic ring constituting the main chain of the polymer, the substituent on the aromatic ring or the aliphatic chain constituting the main chain, It may be introduced into a side chain or the like.
Some or all of these ion exchange groups may form a salt with a counter ion, but when actually used as a polymer electrolyte membrane for a fuel cell, the cation exchange group That is, the case where it is an acid group is preferable, and the case where substantially all the acid groups are free acids is preferable.
Preferred acid _{groups, -SO 3 H, -PO (OH} ) 2, -COOH, -SO 2 NHSO 2 - and the like. More preferred are —SO ₃ H and —PO (OH) ₂ , and —SO ₃ H is particularly preferred.

The polymer electrolyte, which is a constituent of the polymer electrolyte membrane of the present invention, usually has an ion exchange capacity such that the ion exchange capacity of the polymer electrolyte membrane using the polymer electrolyte membrane is about 0.2 to 4 meq / g. used.
Here, when the ion exchange capacity of the polymer electrolyte membrane exceeds 4 meq / g, the water resistance of the membrane tends to decrease, preferably 3 meq / g or less, more preferably 2.5 meq / g or less. Further, when the ion exchange capacity of the polymer electrolyte membrane is lower than 0.2 meq / g, the ionic conductivity of the membrane tends to decrease, and the output as a fuel cell tends to decrease, preferably 0.5 meq / g or more, more preferably 0.8 meq / g or more. Therefore, when the polymer electrolyte membrane contains a polymer non-electrolyte, the polymer electrolyte usually has an ion exchange capacity of about 0.2 to 5.0 meq / g, preferably 0.5 to 4.0 meq. / G, more preferably, one having an ion exchange capacity of about 1.0 to 3.0 meq / g. When the polymer non-electrolyte is not included, it is usually selected from those having an ion exchange equivalent in the above-mentioned range shown for the polymer electrolyte membrane.

The polymer electrolyte membrane of the present invention is composed of the polymer electrolyte as described above or a polymer non-electrolyte as described above. As the polymer electrolyte suitably used, for example, as a repeating unit, the following general formula (1 And those having at least a unit represented by the following general formula (2) and a unit represented by the following general formula (3).
— [(Ar ¹ ) _n —R ¹ — (Ar ² ) _m —X ¹ ] — (1)
(In the formula, R ¹ has an optionally substituted alkylene group having 2 to 10 carbon atoms, an optionally substituted oxyalkylene group having 2 to 10 carbon atoms, and a substituent. Represents a group selected from oxyalkyleneoxy groups having 2 to 10 carbon atoms, and Ar ¹ and Ar ² may each independently have a phenylene group or a substituent which may have a substituent. Represents a group selected from a good biphenylylene group, an optionally substituted triphenylene group, and an optionally substituted naphthylene group, and at least ^{one of} R ¹ , Ar ¹ , and Ar ² is ion-exchangeable X ¹ represents a direct bond, —O—, —S—, —CO—, —SO—, —SO ₂ —, n and m each represents 0 or 1, and n + m represents 1 Or 2.

— [(Ar ³ ) _o —R ² — (Ar ⁴ ) _p —X ² ] — (2)
^{- (Ar 5 -Z 1 -Ar 6} -Z 2) - (3)
(In the formula, R ² has an optionally substituted alkylene group having 2 to 10 carbon atoms, an optionally substituted oxyalkylene group having 2 to 10 carbon atoms, and a substituent. Represents a group selected from oxyalkyleneoxy groups having 2 to 10 carbon atoms, and Ar ³ , Ar ⁴ , Ar ⁵ , Ar ⁶ are each independently a phenylene group or a substituent which may have a substituent. Represents a group selected from a biphenylylene group which may have a substituent, a triphenylene group which may have a substituent, and a naphthylene group which may have a substituent, and at least one of Ar ⁵ and Ar ⁶ is X ² , Z ¹ and Z ² each independently represent a direct bond, —O—, —S—, —CO—, —SO— or —SO ₂ —, and o , P each independently represents 0 or 1.)

In the polymer electrolyte membrane of the present invention, examples of the polymer non-electrolyte suitably used include at least a unit represented by the following general formula (4) as a repeating unit or represented by the following general formula (5). Examples thereof include those having at least a unit and a unit represented by the following general formula (6).
— [(Ar ⁷ ) _q —R ³ — (Ar ⁸ ) _r —X ³ ] — (4)
(In the formula, R ³ has an optionally substituted alkylene group having 2 to 10 carbon atoms, an optionally substituted oxyalkylene group having 2 to 10 carbon atoms, and a substituent. Represents a group selected from oxyalkyleneoxy groups having 2 to 10 carbon atoms, and Ar ⁷ and Ar ⁸ may each independently have a phenylene group or a substituent which may have a substituent. X ³ represents a group selected from a good biphenylylene group, an optionally substituted triphenylene group, and an optionally substituted naphthylene group, and X ³ represents a direct bond, —O—, —S—, —CO. Represents-, -SO-, or -SO _2- , q and r each represents 0 or 1, and q + r represents 1 or 2;
)
-(R ⁴ -X ⁴ )-(5)
-(Ar ⁹ -Z ³ -Ar ¹⁰ -Z ⁴ )-(6)
(In the formula, R ⁴ has an optionally substituted alkylene group having 2 to 10 carbon atoms, an optionally substituted oxyalkylene group having 2 to 10 carbon atoms, and a substituent. Represents a group selected from oxyalkyleneoxy groups having 2 to 10 carbon atoms, and Ar ⁹ and Ar ¹⁰ may independently have a phenylene group or a substituent which may have a substituent. Represents a group selected from a good biphenylylene group, a triphenylene group which may have a substituent, and a naphthylene group which may have a substituent, and X ⁴ , Z ³ and Z ⁴ are each independently a direct bond, It represents any of —O—, —S—, —CO—, —SO—, and —SO ₂ —.)

Here, as the alkylene group having 2 to 10 carbon atoms which may have a substituent, for example, ethylene group, propylene group, butylene group, pentylene group, hexylene group, heptylene group, octylene group, nonylene group, In addition to decamethylene group, etc., these include alkyl groups having 1 to 6 carbon atoms such as methyl, ethyl and n-propyl, alkoxy groups having 1 to 6 carbon atoms such as methoxy, ethoxy and n-propoxy, trifluoromethyl and the like C 1-6 halogenated alkyl group, C 1-6 halogenated alkoxy group such as trifluoromethoxy, C 6-14 aryl group such as phenyl, naphthyl, phenoxy, naphthyloxy, etc. 6-14 aryloxy groups, acetyl groups, benzoyl groups, halogeno groups such as fluoro, chloro and bromo, hydroxyl groups, etc. Such as those obtained by conversion and the like. When there are a plurality of substituents, they may be the same or different.
Among these, an alkylene group having 2 to 10 carbon atoms substituted with a halogeno group is preferred, and a 2,2,3,4,4-hexafluoropentylene group, 2,2,3,3,4,4,5,5. A partially halogenated alkylene group having 2 to 10 carbon atoms such as 1,6,6-decafluoroheptylene group, 1,1,2-trifluoro-2-chloroethylene group, tetrafluoroethylene group, octafluorobutylene group, A perhalogenated alkylene group having 2 to 10 carbon atoms such as dodecafluorohexylene group and hexadecafluorooctylene group is more preferable. Particularly preferred are tetrafluoroethylene group, octafluorobutylene group, dodecafluorohexylene group, hexadecafluorooctylene group and the like.

Examples of the optionally substituted oxyalkylene group having 2 to 10 carbon atoms include an oxyethylene group, an oxypropylene group, an oxybutylene group, an oxypentylene group, an oxyhexylene group, an oxyheptylene group, In addition to oxyoctylene group, oxynonylene group, oxydecamethylene group, etc., these may also include alkyl groups having 1 to 6 carbon atoms such as methyl, ethyl, n-propyl, etc., and 1 carbon atom such as methoxy, ethoxy, n-propoxy, etc. 1 to 6 alkoxy groups, C1-C6 halogenated alkyl groups such as trifluoromethyl, C1-C6 halogenated alkoxy groups such as trifluoromethoxy, and C6-C14 aryls such as phenyl and naphthyl. Group, aryloxy group having 6 to 14 carbon atoms such as phenoxy, naphthyloxy, acetyl group, benzoyl group Fluoro, chloro, halogeno groups such as bromo, and a hydroxyl group and the like obtained by substituting. When there are a plurality of substituents, they may be the same or different.
Among them, an oxyalkylene group having 2 to 10 carbon atoms substituted with a halogeno group is preferable, and an oxy- (2,2,3,4,4-hexafluoro) pentylene group, oxy- (2,2,3,3). , 4,4,5,5,6,6-decafluoro) heptylene group or the like, a partially halogenated oxyalkylene group having 2 to 10 carbon atoms, oxy- (1,1,2-trifluoro-2-chloro) ethylene Perhalogenation having 2 to 10 carbon atoms such as oxy- (tetrafluoro) ethylene group, oxy- (octafluoro) butylene group, oxy- (dodecafluoro) hexylene group, oxy- (hexadecafluoro) octylene group An oxyalkylene group is more preferred. Particularly preferred are oxy- (tetrafluoro) ethylene group, oxy- (octafluoro) butylene group, oxy- (dodecafluoro) hexylene group, oxy- (hexadecafluoro) octylene group and the like.

As the oxyalkyleneoxy group having 2 to 10 carbon atoms which may have a substituent,
For example, oxyethyleneoxy group, oxypropyleneoxy group, oxybutyleneoxy group, oxypentyleneoxy group, oxyhexyleneoxy group, oxyheptyleneoxy group, oxyoctyleneoxy group, oxynonyleneoxy group, oxydecamethyleneoxy group In addition to these, an alkyl group having 1 to 6 carbon atoms such as methyl, ethyl and n-propyl, an alkoxy group having 1 to 6 carbon atoms such as methoxy, ethoxy and n-propoxy, and a carbon such as trifluoromethyl C1-C6 halogenated alkyl groups, C1-C6 halogenated alkoxy groups such as trifluoromethoxy, C6-C14 aryl groups such as phenyl and naphthyl, C6-C6 such as phenoxy and naphthyloxy 14 aryloxy groups, acetyl groups, benzoyl groups, fluoro, chloro Halogeno groups such as bromo, and a hydroxyl group and the like obtained by substituting. When there are a plurality of substituents, they may be the same or different.
Among them, an oxyalkyleneoxy group having 2 to 10 carbon atoms substituted with a halogeno group is preferable, and is an oxy- (2,2,3,4,4-hexafluoro) pentylene-oxy group or oxy- (2,2,3 , 3,4,4,5,5,6,6-decafluoro) heptylene-oxy group or the like, a partially halogenated oxyalkyleneoxy group having 2 to 10 carbon atoms, such as oxy- (1,1,2-trifluoro-) 2-chloro) ethylene-oxy group, oxy- (tetrafluoro) ethylene-oxy group, oxy- (octafluoro) butylene-oxy group, oxy- (dodecafluoro) hexylene-oxy group, oxy- (hexadecafluoro) A perhalogenated oxyalkyleneoxy group having 2 to 10 carbon atoms such as an octylene-oxy group is more preferable. Particularly preferably, oxy- (tetrafluoro) ethylene-oxy group, oxy- (octafluoro) butylene-oxy group, oxy- (dodecafluoro) hexylene-oxy group, oxy- (hexadecafluoro) octylene-oxy group, etc. It is.

Further, substitution in a phenylene group which may have a substituent, a biphenylylene group which may have a substituent, a triphenylene group which may have a substituent, or a naphthylene group which may have a substituent Examples of the group include alkyl groups having 1 to 6 carbon atoms such as methyl, ethyl and n-propyl, alkoxy groups having 1 to 6 carbon atoms such as methoxy, ethoxy and n-propoxy, and 1 to 3 carbon atoms such as trifluoromethyl. 6 halogenated alkyl groups, halogenated alkoxy groups having 1 to 6 carbon atoms such as trifluoromethoxy, aryl groups having 6 to 14 carbon atoms such as phenyl and naphthyl, and aryls having 6 to 14 carbon atoms such as phenoxy and naphthyloxy Examples thereof include an oxy group, an acetyl group, a benzoyl group, a halogeno group such as fluoro, chloro and bromo, and a hydroxyl group. There may be a plurality of substituents, and in this case, they may be the same or different.
Preferable examples of the phenylene group which may have a substituent include, for example, 1,4-phenylene group, 1,3-phenylene group, 1,2-phenylene group, and methyl, ethyl, n- C1-C6 alkyl groups such as propyl, C1-C6 alkoxy groups such as methoxy, ethoxy and n-propoxy, C1-C6 halogenated alkyl groups such as trifluoromethyl, trifluoromethoxy, etc. A halogenated alkoxy group having 1 to 6 carbon atoms, an aryl group having 6 to 14 carbon atoms such as phenyl and naphthyl, an aryloxy group having 6 to 14 carbon atoms such as phenoxy and naphthyloxy, an acetyl group, a benzoyl group, fluoro, Examples include those substituted with a halogeno group such as chloro and bromo, and a hydroxyl group. When there are a plurality of substituents, they may be the same or different. Among these, a 1,4-phenylene group which may be substituted with these substituents is preferable.

Preferred examples of the biphenylylene group which may have a substituent include, for example, 4,4′-biphenylylene group, 3,3′-biphenylylene group, 3,4′-biphenylylene group, and methyl, ethyl , An alkyl group having 1 to 6 carbon atoms such as n-propyl, an alkoxy group having 1 to 6 carbon atoms such as methoxy, ethoxy and n-propoxy, a halogenated alkyl group having 1 to 6 carbon atoms such as trifluoromethyl, tri C1-C6 halogenated alkoxy groups such as fluoromethoxy, C6-C14 aryl groups such as phenyl and naphthyl, C6-C14 aryloxy groups such as phenoxy and naphthyloxy, acetyl groups and benzoyl groups , Halogeno groups such as fluoro, chloro, and bromo, and those substituted with a hydroxyl group. When there are a plurality of substituents, they may be the same or different. Among these, a 4,4′-biphenylylene group which may be substituted with these substituents is preferable.
Preferred examples of the triphenylene group which may have a substituent include, for example, 4,4 "-triphenylene group, 3,3" -triphenylene group, 3,4 "-triphenylene group, and methyl, An alkyl group having 1 to 6 carbon atoms such as ethyl and n-propyl, an alkoxy group having 1 to 6 carbon atoms such as methoxy, ethoxy and n-propoxy, a halogenated alkyl group having 1 to 6 carbon atoms such as trifluoromethyl, C1-C6 halogenated alkoxy groups such as trifluoromethoxy, C6-C14 aryl groups such as phenyl and naphthyl, C6-C14 aryloxy groups such as phenoxy and naphthyloxy, acetyl groups, and benzoyl Group, a halogeno group such as fluoro, chloro and bromo, a hydroxyl group substituted, etc. There are a plurality of substituents. If, they may be the same or different among them, it may be substituted with these substituents 4,4 "-. Triphenylene group.

  Preferable examples of the naphthylene group which may have a substituent include, for example, 1,4-naphthylene group, 2,3-naphthylene group, 1,5-naphthylene group, 2,6-naphthylene group, 2,7 A naphthylene group, a 1,8-naphthylene group, and an alkyl group having 1 to 6 carbon atoms such as methyl, ethyl and n-propyl, and an alkoxy group having 1 to 6 carbon atoms such as methoxy, ethoxy and n-propoxy , Halogenated alkyl groups having 1 to 6 carbon atoms such as trifluoromethyl, halogenated alkoxy groups having 1 to 6 carbon atoms such as trifluoromethoxy, aryl groups having 6 to 14 carbon atoms such as phenyl and naphthyl, phenoxy and naphthyl Substituted by aryloxy groups having 6 to 14 carbon atoms such as oxy, acetyl groups, benzoyl groups, halogeno groups such as fluoro, chloro and bromo, and hydroxyl groups Ones, and the like. When there are a plurality of substituents, they may be the same or different. Among these, a 1,4-naphthylene group, a 1,5-naphthylene group, a 2,6-naphthylene group, and a 2,7-naphthylene group that may be substituted with these substituents are preferable.

As a typical example of the unit represented by the general formula (1), the following may be mentioned in the form of a free acid. Here, k independently represents 0, 1 or 2, and at least one of k in each unit is 1 or 2.

Specific examples of the unit represented by the general formula (2) include the following.

Specific examples of the unit represented by the general formula (3) include the following when expressed in the form of a free acid.

Specific examples of the unit represented by the general formula (4) include the following.

Specific examples of the unit represented by the general formula (5) include the following.

Specific examples of the unit represented by the general formula (6) include the following.

In the present invention, the polymer electrolyte preferably used includes those having at least the repeating unit represented by the general formula (1) as described above, the repeating unit represented by the general formula (2) as described above, and the above-mentioned Although what has at least the repeating unit shown by such General formula (3) etc. is mentioned, it can also have another repeating unit. When it has a plurality of repeating units, it may be an alternating copolymer, a random copolymer, a block copolymer, or a graft copolymer.
The polymer non-electrolyte preferably used includes those having at least the repeating unit represented by the general formula (4) as described above, the repeating unit represented by the general formula (5) as described above, and the above-mentioned Although what has at least the repeating unit shown by General formula (6) is mentioned, it can also have another repeating unit. When it has a plurality of repeating units, it may be an alternating copolymer, a random copolymer, a block copolymer, or a graft copolymer.

The polymer electrolyte and polymer non-electrolyte in the present invention can be produced by a known method such as condensation of a corresponding dihalogeno compound and a corresponding diol compound in a solvent in the presence of an alkali.
As a specific example, the polymer electrolyte represented by the following formula (7) is 1,6-bis (4-fluorophenyl) -dodecafluorohexane, 4,4′-dihydroxybiphenyl, and 4,4′-. Difluoro-3,3′-disulfodiphenylsulfone can be produced by polycondensation in the presence of an alkali. In addition, the polymer electrolyzed protein represented by the following formula (8) can be produced by reacting polyethylene oxide having a hydroxyl group at the chain end with polyethersulfone having both ends fluorinated.

The polymer electrolyte membrane of the present invention may contain a polymer non-electrolyte as described above in addition to the polymer electrolyte as described above, but the combination is not particularly limited, Even a polymer electrolyte membrane composed of only one type of polymer electrolyte may be a polymer electrolyte composed of a plurality of types of polymer electrolytes and a plurality of types of polymer non-electrolytes.
In producing such a polymer electrolyte membrane, the method is not particularly limited, but a method of forming a membrane from a solution state (solution casting method) is preferably used.
Specifically, a polymer electrolyte membrane and a polymer non-electrolyte used as necessary are dissolved in an appropriate solvent, the solution is cast on a glass plate, and the solvent is removed to obtain a polymer electrolyte membrane. A film is formed. The solvent used for film formation is not particularly limited as long as it is capable of dissolving the polymer electrolyte and the polymer non-electrolyte used as necessary, and can be removed thereafter. N, N-dimethylformamide, N, Aprotic polar solvents such as N-dimethylacetamide (DMAc), N-methyl-2-pyrrolidone, dimethylsulfoxide, chlorinated solvents such as dichloromethane, chloroform, 1,2-dichloroethane, chlorobenzene, dichlorobenzene, methanol, ethanol, Alcohols such as propanol, alkylene glycol monoalkyl ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, and propylene glycol monoethyl ether are preferably used. These can be used singly, but two or more solvents can be mixed and used as necessary. Of these, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, dimethylsulfoxide and the like are preferable because of high solubility of the polymer.

The polymer electrolyte membrane of the present invention may be a composite membrane obtained by a method such as impregnation with a porous film or sheet (porous membrane) or mixing with a fibrous polymer.
That is, among the constituents of the polymer electrolyte membrane of the present invention, the polymer electrolyte of the present invention is applied to a porous film or sheet (porous membrane) made of at least one polymer electrolyte and / or polymer non-electrolyte. A composite membrane can be obtained by impregnating and polymerizing a polymer electrolyte and / or a polymer non-electrolyte, which are constituent components of the membrane. At this time, the constituent of the porous film or sheet preferably includes a polymer non-electrolyte, and the component to be impregnated preferably includes a polymer electrolyte.
In addition, among the constituent components of the polymer electrolyte membrane of the present invention, a fibrous material composed of at least one polymer electrolyte and / or a polymer non-electrolyte, and a high component that is a constituent component of the polymer electrolyte membrane of the present invention. A composite membrane can be obtained by forming a film by mixing a molecular electrolyte and / or a polymer non-electrolyte. At this time, the constituent of the fibrous material preferably includes a polymer non-electrolyte, and the component mixed with the fibrous material preferably includes a polymer electrolyte.

Here, since the porous membrane is used for further improvement of the strength, flexibility and durability of the polymer electrolyte membrane, it can be used regardless of its shape as long as it satisfies its intended purpose. When used as a membrane for a polymer fuel cell, the film thickness is usually 1 to 100 μm, preferably 3 to 30 μm, more preferably 5 to 20 μm, and the pore diameter is usually 0.01 to 10 μm, preferably 0.02 to 7 μm. The porosity is usually 20 to 98%, preferably 30 to 95%. In addition, the material of the porous membrane is preferably a polymer non-electrolyte and a polymer having an aliphatic chain in the main chain. As a method for producing these porous films, a known method can be used.
In addition, since the fibrous material is used to further improve the strength, flexibility, and durability of the polymer electrolyte membrane, the fibrous material can be formed into a shape such as a length and a thickness as long as the purpose of use is satisfied. It can be used regardless. When used as a diaphragm for a polymer electrolyte fuel cell, the weight composition ratio of the fibrous material in the polymer electrolyte membrane is preferably 0.1% to 20%. The material of the fibrous material is preferably a polymer non-electrolyte and a polymer having an aliphatic chain in the main chain. A known method can be used as a method for producing these fibrous materials.

  There is no particular limitation on the method of combining the porous membrane and the fibrous material. For example, a method of obtaining a composite membrane by impregnating the porous membrane in a polymer electrolyte solution and taking out the porous membrane and then drying the solvent, A method of applying a molecular electrolyte solution to a porous membrane and drying the solvent to obtain a composite membrane, contacting the porous membrane with a polymer electrolyte solution under reduced pressure, and then returning to normal pressure by bringing the solution into the pores of the porous membrane Examples thereof include a method of impregnating and drying a solvent to obtain a composite membrane, a method of mixing a fibrous material and a polymer electrolyte solution, and then forming a membrane according to the solution casting method described above.

Thus, a polymer electrolyte membrane can be obtained. In the present invention, a polymer electrolyte having an elastic modulus of 400 MPa to 900 MPa at 23 ° C. and a relative humidity of 50% is selected.
Next, the fuel cell will be described.
The fuel cell of the present invention can be produced by bonding a catalyst and a conductive material as a current collector to both surfaces of the polymer electrolyte membrane as described above.
The catalyst is not particularly limited as long as it can activate the oxidation-reduction reaction with hydrogen or oxygen, and a known catalyst can be used, but platinum fine particles are preferably used.
Platinum fine particles are preferably used by being supported on particulate or fibrous carbon such as activated carbon or graphite.
As for the conductive substance as the current collector, a known material can be used, but a porous carbon non-woven fabric or carbon paper is preferable in order to efficiently transport the raw material gas to the catalyst.
Here, for a method of bonding platinum fine particles or carbon carrying platinum fine particles to a porous carbon non-woven fabric or carbon paper, and a method of bonding it to a polymer electrolyte membrane, see, for example, J. Org. Electrochem. Soc. : Known methods such as those described in Electrochemical Science and Technology, 1988, 135 (9), 2209 can be used.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these.

Elastic modulus The elastic modulus was determined from a tensile test conducted at 23 ° C. and 50% relative humidity in accordance with Japanese Industrial Standard (JIS K 7127).

Dry / wet cycle test 10 mg of platinum catalyst supported on carbon (platinum loading 30%) was mixed with 0.1 ml of a lower alcohol solution of Nafion (registered trademark of DuPont) (containing 10 wt% of water) (manufactured by Aldrich). The paste was applied to a porous carbon woven fabric as an electrode material and dried to obtain a current collector as an electrode material on which the catalyst was fixed. This current collector was superposed on both sides of the membrane to obtain a membrane-electrode assembly. A single fuel cell was obtained by incorporating this membrane-electrode assembly into a fuel cell.
A process in which humidified nitrogen passing through a bubbler maintained at 95 ° C. for 30 minutes and dry nitrogen not passing through a bubbler for 30 minutes was sent to both sides of the anode and cathode of a fuel cell single cell maintained at 95 ° C. for one cycle. The hydrogen permeation amount of the membrane was used as an index of the mechanical deterioration of the membrane with respect to this wet and dry cycle. It can be said that the greater the number of cycles at which the hydrogen permeation amount exceeds a certain level, the higher the mechanical durability.
The hydrogen permeation amount was measured by the following method. Hydrogen was sent to the anode side and nitrogen to the cathode side of the single fuel cell, and a potentiostat / galvanostat was connected. First, the back pressure was set to 1 atm (gauge reading) for both electrodes, the voltage was swept between 0.2 V to 0.6 V, and the current value (I _b ) obtained at that time was recorded. Next, the back pressure on the cathode side was set to 0.5 atm (gauge reading) while the back pressure on the anode side was kept unchanged, and the voltage was swept between 0.2 V to 0.6 V and obtained at that time. The current value (I _u ) was recorded. At this time, the difference in current between when the back pressure is equal and when the differential pressure is applied, that is, I _b −I _u is converted to the volume of permeated hydrogen, and the hydrogen permeation amount is obtained.

Viscosity measuring polymer electrolyte was dissolved in N, N-dimethylformamide (DMF) to prepare a 0.01 g / mL solution. The specific viscosity of this solution was measured at 40 ° C. with an Ubbelohde viscometer.

Synthesis example 1
Synthesis Example of Random Copolymer (RC-1) In a flask, 26.64 g of p-fluoroiodobenzene and 100 ml of dehydrated dimethyl sulfoxide were placed at room temperature, 15.24 g of copper powder was added, and the mixture was stirred at 110 ° C. 30.46 g of 1,6-diiodododecafluorohexane was slowly added dropwise thereto and stirred at 120 ° C. for 24 hours. The reaction solution was allowed to cool and then filtered, and then added dropwise to the aqueous solution to collect the precipitate. The precipitate was dissolved in acetone and filtered, and then acetone was distilled off. The residue was dissolved in methanol and precipitated into water. The precipitate was purified by distillation under reduced pressure (155 ° C., 5 mmHg) to obtain the desired 1,6-bis (4-fluorophenyl) dodecafluorohexane (hereinafter abbreviated as M-1).
The NMR measurement results are shown below. ¹ H-NMR (ppm): 7.49, 7.77, ¹⁹ F-NMR (ppm): -108, -110, -122.
Next, 2 g of 4,4′-dihydroxybiphenyl, 1.559 g of potassium carbonate, 14 ml of N-methylpyrrolidone, and 5 ml of toluene were added to the flask under a nitrogen stream. Azeotropic dehydration was carried out while distilling off toluene at 180 ° C. Next, 2.634 g of M-1 above, 2.635 g of potassium 4,4′-difluorodiphenylsulfone-3,3′-disulfonate were added, and the mixture was stirred at 180 ° C. for 8.5 hours. The reaction liquid after standing to cool was dropped into acidic methanol in hydrochloric acid, and the resulting precipitate was collected by filtration, washed with methanol and water, and dried under reduced pressure at 40 ° C.
5.82g of polymer electrolyte RC-1 of following formula (9) which is a random copolymer was obtained as brown powder. When the ion exchange capacity of the polymer electrolyte was measured by a titration method, it was 1.3 meq / g. The specific viscosity of RC-1 was 1.25.

Synthesis example 2
Synthesis Example of Polyethersulfone (Terminal-F Type ) 1000 g of Sumika Excel PES4003P (manufactured by Sumitomo Chemical, hydroxyl-terminated polyethersulfone, number average molecular weight: 39000) 1000 g, potassium carbonate 7.59 g under nitrogen in a flask. DMAc 2500 ml and toluene 500 ml were added, and azeotropic dehydration was performed by heating and stirring at 160 ° C. After allowing to cool at room temperature, 53.6 g of decafluorobiphenyl was added and the mixture was heated and stirred at 80 ° C. for 3.5 hours. After allowing to cool, the reaction solution is added dropwise to a large amount of water, and the resulting precipitate is collected by filtration, washed with a methanol / acetone mixed solvent, dried at 80 ° C., and the following formula (10) of both terminal F groups (Hereinafter abbreviated as P-1).

Synthesis example 3
Polyethylene oxide (hereinafter abbreviated as PEO) and (hereinafter abbreviated as PES) polyethersulfone PEO 15 g of molecular weight 70,000 with a hydroxyl group in Synthesis Example chain ends of the block copolymer as a constituent is dissolved in DMAc20ml the toluene After azeotropic dehydration by adding 5 ml, the mixture was allowed to cool to room temperature. Thereto, 30 mg of oily NaH (60 wt%) was added and stirred at room temperature, and the chain end hydroxyl group was converted to a sodium salt. Furthermore, the target block copolymer was obtained by adding and stirring 5g of said P-1. This block copolymer solution was poured into methanol, and a polymer of the following formula (11) (hereinafter abbreviated as BC-1) was taken out. ^It was PES: PEO = 1.0: 1.9 when the weight ratio of each segment was computed from < ¹ > H * NMR measurement.

Synthesis example 4
Synthesis example of poly (oxy (3,3′-diphenyl-4,4′-biphenylylene) oxy-4,4′-biphenylylene) (both ends—OH type) 3,3′-diphenyl-4 under nitrogen in a flask , 4′-dihydroxybiphenyl, 19.26 g of 4,4′-dibromobiphenyl, 80 g of benzophenone, and 20 ml of toluene were added and dissolved by stirring. 9.49 g of potassium carbonate was added thereto, heated and stirred, and dehydrated under azeotropic conditions of toluene and water, and then toluene was distilled off. Further, 5 ml of a previously prepared cuprous chloride / quinoline catalyst (0.1 g / 10 ml) was added, and the mixture was heated and stirred at 210 ° C. for 6 hours. The reaction solution was poured into a large amount of acetic acid-containing methanol, and the resulting precipitate was filtered and dried to obtain a polymer of the following formula (12) having hydroxyl groups at both ends (hereinafter abbreviated as P-2).

Synthesis example 5
Synthesis Example of Block Copolymer (BC-2) To a flask, 100 g of P-2 synthesized according to the conditions of Synthesis Example 4, 8.29 g of potassium carbonate, 3000 ml of DMAc, and 250 ml of toluene were added, and the mixture was heated and stirred at 150 ° C. Azeotropic dehydration. After allowing to cool to room temperature, 400 g of P-1 synthesized according to the conditions of Synthesis Example 2 was added and stirred at 80 ° C. for 6 hours. After allowing to cool, the reaction solution was dropped into a large amount of hydrochloric acid methanol, and the resulting precipitate was collected by filtration and dried at 80 ° C. to obtain a block copolymer. The obtained block copolymer was dissolved in concentrated sulfuric acid and subjected to sulfonation reaction at 60 ° C. The obtained solution was dropped into a large amount of ice water, and the precipitate was collected by filtration. Furthermore, after repeating the mixer washing | cleaning by ion-exchange water until a washing | cleaning liquid becomes neutral, it dried and the sulfonated following formula (13) block copolymer BC-2 was obtained. As a result of 1H-NMR measurement of BC-2 in a heavy DMSO solvent, signals resulting from the sulfonated product of PES described in Reference Example 1 below were not substantially observed. In particular, it was confirmed that it was not introduced into the segment derived from P-1, but was selectively introduced into the segment derived from P-2. ^When the weight ratio of each segment was calculated from ¹ H-NMR measurement, it was (PES) :( sulfonic acid substitution product of P-2 segment) = 2.0: 1.0. The relative viscosity was 1.03, and the ion exchange capacity measured by a titration method was 1.5 meq / g.

Synthesis Example 6
Synthesis Example of Block Copolymer (BC-3) After stirring 0.2 g of anhydrous ferric chloride and 1 ml of propylene oxide in 4 ml of ether at 0 ° C. for 10 minutes, the temperature was raised to room temperature and the pressure was reduced to ether and volatile components. To prepare a catalyst. To this were added 17.74 g of phenylglycidyl ether and 2.37 g of epichlorohydrin, and the mixture was heated and stirred at 100 ° C. for 1 hour and at 160 ° C. for 8 hours. The polymer solution was poured into methanol and the precipitate was filtered and dried to obtain a poly (phenylglycidyl ether-co-epichlorohydrin) polymer (hereinafter abbreviated as GE2).
8 g of Sumika Excel PES5003P (manufactured by Sumitomo Chemical Co., Ltd., hydroxyl-terminated polyethersulfone) and 0.1 g of potassium carbonate were dissolved in 40 ml of DMAc and 5 ml of toluene, and heated to distill toluene. 2 g of GE2 was added thereto, and the mixture was heated and stirred at 160 ° C for 3.5 hours. The reaction solution was poured into dilute hydrochloric acid to precipitate a polymer, filtered, washed with water, and dried to recover the block copolymer. The obtained block copolymer was mixed with 40 g of concentrated sulfuric acid and dissolved, and then poured into a large amount of water to precipitate a polymer, filtered, washed with water, dried and sulfonated to obtain a block copolymer of the following formula (14) ( BC-3) was obtained. The ion exchange capacity of BC-3 was measured by a titration method and found to be 1.0 meq / g. On the other hand, since BC-3 contains some gel and does not completely dissolve in various solvents, it is difficult to measure specific viscosity.

Synthesis example 7
Synthesized according to the method described in Example 1 of Synthesis Example JP 2001-250567 JP-block copolymer (BC-4), to obtain a block copolymer BC-4 of the formula (15). The relative viscosity of BC-4 was 0.91, and the ion exchange capacity measured by a titration method was 1.6 meq / g.

Reference example 1
1.5 g of SUMIKAEXCEL PES5200P (manufactured by Sumitomo Chemical Co., Ltd., chloro group-terminated polyethersulfone) was dissolved in 20 g of 10% fuming sulfuric acid and sulfonated at room temperature for 3 days. Thereafter, the polymer sulfuric acid solution was poured into ice water for dilution, and the polymer dilute sulfuric acid solution was dialyzed with a dialysis membrane (UC36-32-100, manufactured by Sanko Junyaku Co., Ltd.) for 2 days to remove sulfuric acid. The aqueous solution after dialysis was concentrated and dried to obtain sulfonated PES.
As a result of 1H-NMR measurement of sulfonated PES in heavy DMSO solvent, signals were observed in 7.05 ppm, 7.90 ppm, and 8.29 ppm that were not observed in PES5200P before sulfonation, It was confirmed that sulfonic acid groups were introduced.

Example 1
A transparent, tough, and flexible film obtained by dissolving RC-1 obtained in Synthesis Example 1 in DMAc at a concentration of about 15% by weight, casting on a glass plate, drying at 80 ° C. and removing the solvent. Got. When the ion exchange capacity of the membrane was measured by a titration method, it was 1.3 meq / g. Table 1 shows the elastic modulus of this film and the results of the wet and dry cycle test.

Example 2
BC-1 obtained in Synthesis Example 3 and BC-2 obtained in Synthesis Example 5 were weighed to a weight ratio of 1: 2, dissolved in DMAc at a concentration of about 15% by weight, and cast onto a glass plate. Then, the film was dried at 80 ° C. to remove the solvent, thereby obtaining a transparent, tough and flexible film. The ion exchange capacity of the membrane was measured by a titration method and found to be 1.0 meq / g. Table 1 shows the elastic modulus of this film and the results of the wet and dry cycle test.

Example 3
A transparent, tough, and flexible film is obtained by dissolving BC-3 obtained in Synthesis Example 6 in DMAc at a concentration of about 15% by weight, casting it on a glass plate, drying at 80 ° C. and removing the solvent. Got. The ion exchange capacity of the membrane was measured by a titration method and found to be 1.0 meq / g. Table 1 shows the elastic modulus of this film and the results of the wet and dry cycle test.

Comparative Example 1
A transparent film was obtained in the same manner as in Example 2 except that BC-1 and BC-2 were weighed so as to have a weight ratio of 2: 1. The ion exchange capacity of the membrane was measured by a titration method and found to be 0.5 meq / g. Table 1 shows the elastic modulus of this film and the results of the wet and dry cycle test.

Comparative Example 2
BC-4 obtained in Synthesis Example 7 was dissolved in DMAc at a concentration of about 15% by weight, cast on a glass plate, dried at 80 ° C., and the solvent was removed to obtain a transparent brown film. When the ion exchange capacity of the membrane was measured by a titration method, it was 1.6 meq / g. Table 1 shows the elastic modulus of this film and the results of the wet and dry cycle test.

Claims (8)

  The elastic modulus is 400 MPa to 900 MPa at 23 ° C. and 50% relative humidity, and all of the polymer as a constituent component has an aromatic ring in its main chain, and at least one kind has an aliphatic chain in its main chain. A polymer electrolyte membrane, comprising at least one polymer electrolyte.   2. The polymer electrolyte membrane according to claim 1, wherein the polymer electrolyte membrane has an ion exchange capacity of 0.2 to 4 meq / g. The polymer electrolyte has at least a unit represented by the following general formula (1) as a repeating unit, or at least a unit represented by the following general formula (2) and a unit represented by the following general formula (3). The polymer electrolyte membrane according to claim 1 or 2.
— [(Ar ¹ ) _n —R ¹ — (Ar ² ) _m —X ¹ ] — (1)
(In the formula, R ¹ has an optionally substituted alkylene group having 2 to 10 carbon atoms, an optionally substituted oxyalkylene group having 2 to 10 carbon atoms, and a substituent. Represents a group selected from oxyalkyleneoxy groups having 2 to 10 carbon atoms, and Ar ¹ and Ar ² may each independently have a phenylene group or a substituent which may have a substituent. Represents a group selected from a good biphenylylene group, a triphenylene group which may have a substituent, and a naphthylene group which may have a substituent, and at least ^{one of} R ¹ , Ar ¹ and Ar ² is ion-exchangeable X ¹ represents a direct bond, —O—, —S—, —CO—, —SO—, —SO ₂ —, n and m each represents 0 or 1, and n + m represents 1 Or 2.
— [(Ar ³ ) _o —R ² — (Ar ⁴ ) _p —X ² ] — (2)
^{- (Ar 5 -Z 1 -Ar 6} -Z 2) - (3)
(In the formula, R ² has an optionally substituted alkylene group having 2 to 10 carbon atoms, an optionally substituted oxyalkylene group having 2 to 10 carbon atoms, and a substituent. Represents a group selected from oxyalkyleneoxy groups having 2 to 10 carbon atoms, and Ar ³ , Ar ⁴ , Ar ⁵ , Ar ⁶ are each independently a phenylene group or a substituent which may have a substituent. Represents a group selected from a biphenylylene group which may have a substituent, a triphenylene group which may have a substituent, and a naphthylene group which may have a substituent, and at least one of Ar ⁵ and Ar ⁶ is X ² , Z ¹ and Z ² each independently represent a direct bond, —O—, —S—, —CO—, —SO— or —SO ₂ —, and o And p each independently represents 0 or 1.) Ion exchange _{groups, -SO 3 H, -PO (OH} ) 2, -COOH, -SO 2 NHSO 2 - it from a group selected characterized by claim 3 the polymer electrolyte membrane according.   The polymer electrolyte membrane according to any one of claims 1 to 4, wherein the main chain in the polymer electrolyte is a block copolymer composed of an aromatic segment and an aliphatic segment. As a repeating unit, a polymer non-electrolyte having at least a unit represented by the following general formula (4) is contained, or at least a unit represented by the following general formula (5) and a unit represented by the following general formula (6) The polymer electrolyte membrane according to claim 1, comprising a polymer non-electrolyte having the polymer electrolyte.
— [(Ar ⁷ ) _q —R ³ — (Ar ⁸ ) _r —X ³ ] — (4)
(In the formula, R ³ has an optionally substituted alkylene group having 2 to 10 carbon atoms, an optionally substituted oxyalkylene group having 2 to 10 carbon atoms, and a substituent. Represents a group selected from oxyalkyleneoxy groups having 2 to 10 carbon atoms, and Ar ⁷ and Ar ⁸ may each independently have a phenylene group or a substituent which may have a substituent. X ³ represents a group selected from a good biphenylylene group, an optionally substituted triphenylene group, and an optionally substituted naphthylene group, and X ³ represents a direct bond, —O—, —S—, —CO. Represents-, -SO-, or -SO _2- , q and r each represents 0 or 1, and q + r represents 1 or 2;
)
-(R ⁴ -X ⁴ )-(5)
-(Ar ⁹ -Z ³ -Ar ¹⁰ -Z ⁴ )-(6)
(In the formula, R ⁴ has an optionally substituted alkylene group having 2 to 10 carbon atoms, an optionally substituted oxyalkylene group having 2 to 10 carbon atoms, and a substituent. Represents a group selected from oxyalkyleneoxy groups having 2 to 10 carbon atoms, and Ar ⁹ and Ar ¹⁰ may independently have a phenylene group or a substituent which may have a substituent. Represents a group selected from a good biphenylylene group, a triphenylene group which may have a substituent, and a naphthylene group which may have a substituent, and X ⁴ , Z ³ and Z ⁴ are each independently a direct bond, It represents any of —O—, —S—, —CO—, —SO—, and —SO ₂ —.)   The polymer electrolyte membrane according to claim 6, wherein the polymer non-electrolyte is a block copolymer. A fuel cell comprising the polymer electrolyte membrane according to claim 1.