JPWO2008038702A1 - Sulfonic acid group-containing polymer, production method thereof, polymer electrolyte membrane using sulfonic acid group-containing polymer, membrane / electrode assembly, and fuel cell - Google Patents

Abstract

Disclosed is a novel sulfonic acid group-containing polymer which is excellent in flexibility and stability and is suitable for applications such as fuel cells. A sulfonic acid group-containing polymer having at least a structure represented by the following chemical formulas 1 and 2 as a structural unit. [In the chemical formulas 1 and 2, X represents —S (═O) 2 — or —C (═O) — group, Y represents H or a monovalent cation, and R 1 represents 1 to 1 carbon atoms. Any one of 10 alkylene groups, arylene groups, and direct bonds, R2 is an alkylene group or aralkylene group having 2 to 20 carbon atoms, Ar1 is a divalent aromatic group having an electron-withdrawing group, and n and m are Represents the number of moles of each structural unit. ] [Selection figure] None

Description

  The present invention relates to a sulfonic acid group-containing polymer having a novel structure, a production method thereof, a polymer electrolyte membrane using the polymer, a membrane / electrode assembly, and a fuel cell.

  In recent years, new power generation technologies with excellent energy efficiency and environmental friendliness have attracted attention. Among them, polymer electrolyte fuel cells using polymer electrolyte membranes have high energy density, and have characteristics such as easy start and stop because of lower operating temperatures than other types of fuel cells. Developments as power supply devices for electric vehicles and distributed power generation are advancing.

  As the polymer solid electrolyte membrane, a proton conductive polymer electrolyte membrane is usually used. In addition to proton conductivity, the polymer solid electrolyte membrane must have characteristics such as fuel permeation deterrence and mechanical strength that prevent permeation of hydrogen and the like of the fuel. As such a polymer solid electrolyte membrane, a membrane containing a perfluorocarbon sulfonic acid polymer into which a sulfonic acid group has been introduced is known. However, since fluorine is contained in the molecule, harmful hydrofluoric acid is generated in the exhaust gas depending on the use conditions, and the environmental load is high at the time of disposal.

Although perfluorocarbon sulfonic acid polymer electrolyte membranes have well-balanced characteristics as fuel cell electrolyte membranes, the synthesis method is complicated, and in order to obtain better membranes in terms of cost and performance, hydrocarbon-based polymer electrolyte membranes Polymer electrolyte membranes have been actively developed.
Many hydrocarbon polymer electrolyte membranes use a polymer in which an ionic group such as a sulfonic acid group is introduced into a heat-resistant polymer such as polyimide or polysulfone (see, for example, Patent Document 1).

  In general, it is necessary to introduce more ionic groups in a hydrocarbon polymer electrolyte membrane in order to develop proton conductivity equivalent to that of a perfluorocarbon sulfonic acid polymer electrolyte membrane. However, generally, when the amount of ionic groups increases, the durability tends to decrease. Therefore, there is also a hydrocarbon-based polymer electrolyte membrane in which the polymer structure is improved and the swelling property is further suppressed (see, for example, Patent Document 2).

  However, since aromatic hydrocarbon polymer electrolyte membranes tend to become brittle when dried, it has been proposed to incorporate aliphatic groups into the main chain structure (see, for example, Patent Document 3). reference). However, aliphatic groups such as oxyalkylene groups and oxyalkyleneoxy groups listed as specific structures are susceptible to cleavage by oxidation and are not suitable for polymer electrolyte membranes of fuel cells. Was. Moreover, although the alkylene group which has an aromatic group at both ends is illustrated, since the effect of introducing an aliphatic group is impaired by the aromatic group, it may not be preferable.

JP-T-2004-509224 Japanese Patent Application Laid-Open No. 2004-149779 JP 2006-45512 A

The synthetic polymer in Synthesis Example 1 of the present invention, by using a VARIAN Co. GEMINI-200, is a ¹ H-NMR spectrum was measured at room temperature in deuterated dimethylsulfoxide. The synthetic polymer in Synthesis Example 3 of the present invention, by using a VARIAN Co. GEMINI-200, is a ¹ H-NMR spectrum was measured at room temperature in deuterated dimethylsulfoxide. It is the ¹ H-NMR spectrum which measured the polymer synthesize | combined in the synthesis example 10 in this invention at room temperature in deuterated dimethyl sulfoxide using VARIAN-made GEMINI-200. The synthetic polymer in Synthesis Example 11 of the present invention, by using a VARIAN Co. GEMINI-200, is a ¹ H-NMR spectrum was measured at room temperature in deuterated dimethylsulfoxide. The synthetic polymer in Synthesis Example 12 of the present invention, by using a VARIAN Co. GEMINI-200, is a ¹ H-NMR spectrum was measured at room temperature in deuterated dimethylsulfoxide. The synthetic polymer in Synthesis Example 17 of the present invention, by using a VARIAN Co. GEMINI-200, is a ¹ H-NMR spectrum was measured at room temperature in deuterated dimethylsulfoxide. The synthetic polymer in Synthesis Example 18 of the present invention, by using a VARIAN Co. GEMINI-200, is a ¹ H-NMR spectrum was measured at room temperature in deuterated dimethylsulfoxide. In addition, the symbol in a figure represents the following meaning, respectively. NMP: A signal derived from N-methyl-2-pyrrolidone which is a polymerization solvent contained as an impurity in the polymer. DMSO: signal derived from dimethyl sulfoxide in deuterated dimethyl sulfoxide. H ₂ O: signal derived from water adsorbed on the polymer. Acetone: A signal derived from the residue of acetone used for washing the NMR measuring tube.

  The present invention has been made against the background of the problems of the prior art, and is to provide a stable novel sulfonic acid group-containing polymer that does not have the above-described drawbacks even when an aliphatic group is introduced into the main chain structure. It is an object of the present invention to provide uses such as a polymer electrolyte membrane exhibiting conductivity and durability, a membrane / electrode assembly using the polymer electrolyte membrane, and a fuel cell.

As a result of intensive studies to solve the above problems, the present inventors have found that excellent characteristics can be obtained by using an aliphatic bissulfide structure as a structure for introducing an aliphatic chain, and finally complete the present invention. It came to. That is, the present invention
(1) A sulfonic acid group-containing polymer having at least a structural unit represented by the following chemical formulas 1 and 2.
[In Chemical Formulas 1 and 2, X represents an —S (═O) ₂ — group or —C (═O) — group, Y represents H or a monovalent cation, and R ¹ represents an alkylene having 1 to 10 carbon atoms. Any one of a group, an oxyalkylene group, an arylene group and a direct bond (with a benzene ring and a SO ₃ Y group), R ² is an alkylene having 2 to 20 carbon atoms which may contain a sulfur atom or an oxygen atom. A group or an aralkylene group, Ar ¹ represents a divalent aromatic group having an electron-withdrawing group, and n and m represent an integer of 1 to 1000 in terms of the number of moles of each structural unit in the polymer molecule. ]
(2) The sulfonic acid group-containing polymer according to (1), further having a structure represented by the following chemical formulas 3 and 4 as a structural unit.
[In the chemical formulas 3 and 4, X represents an —S (═O) ₂ — group or —C (═O) — group, Y represents H or a monovalent cation, and R ¹ represents an alkylene having 1 to 10 carbon atoms. Any one of a group, an oxyalkylene group, an arylene group and a direct bond (a benzene ring and a SO ₃ Y group), Ar ¹ is a divalent aromatic group having an electron-withdrawing group, and Z ¹ is an oxygen atom or Z ² represents an oxygen atom, a sulfur atom, a —C (CH ₃ ) ₂ — group, a —C (CF ₃ ) ₂ — group, a —CH ₂ — group, a cyclohexylene group and a direct bond ( O and p each represent an integer of 1 to 1000 in terms of the number of moles of each structural unit in the polymer molecule. ]
(3) The sulfonic acid group-containing polymer according to (1) or (2), further having a structure represented by the following chemical formulas 5 and 6 as a structural unit.
[In Chemical Formulas 5 and 6, X represents an —S (═O) ₂ — group or —C (═O) — group, Y represents H or a monovalent cation, and R ¹ represents an alkylene having 1 to 10 carbon atoms. Any one of a group, an oxyalkylene group, an arylene group, and a direct bond (a benzene ring and an SO ₃ Y group), Ar ¹ represents a divalent aromatic group having an electron-withdrawing group, and Z ³ represents Either an oxygen atom or a sulfur atom, Ar ² is a trivalent or tetravalent group containing an aromatic group, q is 1 or 2, and r and s are the number of moles of each structural unit in the polymer molecule. The integer of 1-1000 is represented. ]
(4) The sulfonic acid group-containing polymer according to (1) to (3), wherein Ar ¹ in chemical formulas 2, 4 and 6 is at least one of structural units represented by chemical formulas 7 to 10 below.
(5) The sulfonic acid group-containing polymer according to any one of (1) to (3), wherein Ar ¹ in Chemical Formulas 2, 4 and 6 is a structure represented by Chemical Formula 9 or 10.
(6) The sulfonic acid group-containing polymer according to any one of (1) to (3), wherein R ¹ in the chemical formulas 1, 3, 5 and 12 is a direct bond with the SO ₃ Y group.
(7) R ² in Chemical Formula 1 and 2 is a linear alkylene group (1) to (3) sulfonic acid group-containing polymer according to.
(8) The sulfonic acid group-containing polymer according to (2), wherein Z ¹ in Chemical Formulas 3 and 4 is an oxygen atom.
(9) The sulfonic acid group-containing polymer according to (2), wherein Z ² in Chemical Formulas 3 and 4 is a direct bond of a benzene ring.
(10) The sulfonic acid group-containing group according to (2), wherein Z ² in Chemical Formulas 3 and 4 is any one of a —C (CH ₃ ) ₂ — group, a —C (CF ₃ ) ₂ — group, and a cyclohexylene group. polymer.
(11) The sulfonic acid group-containing polymer according to (3), wherein Z ³ in chemical formulas 5 and 6 is an oxygen atom.
(12) The sulfonic acid group-containing polymer according to (3), wherein Ar ² in Chemical Formulas 3 and 4 is a benzene ring.
(13) The sulfonic acid group-containing polymer according to (3), wherein q in Chemical Formulas 5 and 6 is 1.

(14) The sulfonic acid group-containing polymer according to any one of (1) to (13), wherein n, m, o, p, r, and s in chemical formulas 1 to 6 satisfy the following formulas 1 to 3.
0.05 ≦ (n + o + r) / (n + m + o + p + r + s) ≦ 0.70 (Formula 1)
0.01 ≦ (o + p) / (n + m + o + p + r + s) ≦ 0.99 (Formula 2)
0 ≦ (r + s) / (n + m + o + p + r + s) ≦ 0.10 (Formula 3)
0.01 ≦ (n + m) / (n + m + o + p + r + s) ≦ 1.00 (Formula 4)
(15) A polymer electrolyte membrane comprising the sulfonic acid group-containing polymer as described in (1) to (14).
(16) The polymer electrolyte membrane according to (15), wherein n, m, o, p, r, and s in chemical formulas 1 to 6 satisfy the following formulas 4 to 6 and are for direct methanol fuel cells.
0.05 ≦ (n + o + r) / (n + m + o + p + r + s) ≦ 0.40 (Formula 5)
0.10 ≦ (o + p) / (n + m + o + p + r + s) ≦ 0.90 (Formula 6)
0 ≦ (r + s) / (n + m + o + p + r + s) ≦ 0.10 (Formula 7)
0.1 ≦ (n + m) / (n + m + o + p + r + s) ≦ 0.9 (Formula 8)
(17) The polymer electrolyte membrane according to (15), wherein n, m, o, p, r, and s in chemical formulas 1 to 6 satisfy the following formulas 7 to 9 and are for a fuel cell using hydrogen as a fuel.
0.15 ≦ (n + o + r) / (n + m + o + p + r + s) ≦ 0.70 (Equation 9)
0.01 ≦ (o + p) / (n + m + o + p + r + s) ≦ 0.70 (Formula 10)
0 ≦ (r + s) / (n + m + o + p + r + s) ≦ 0.10 (Formula 11)
0.05 ≦ (n + m) / (n + m + o + p + r + s) ≦ 0.8 (Formula 12)

(18) A membrane / electrode assembly comprising the polymer electrolyte membrane according to (15) to (17) and an electrode catalyst layer.
(19) A membrane / electrode assembly using the sulfonic acid group-containing polymer of any one of (1) to (14) for the electrode catalyst layer of the membrane / electrode assembly.

(20) A fuel cell comprising the membrane / electrode assembly according to (18) or (19).

(21) A method for producing an aromatic nucleophilic substitution reaction of a sulfonic acid group-containing polymer of (1), wherein when introducing an aliphatic group into the main chain structure, a compound having a structure represented by Chemical Formula 11 is used as a reaction component. A method for producing a sulfonic acid group-containing polymer, characterized by being used as one of the following.
[In Chemical Formula 11, R ³ represents a C 2-20 alkylene group or an aralkylene group which may contain a sulfur atom or an oxygen atom. ]
It is.

The novel sulfonic acid group-containing polymer according to the present invention has improved polymer flexibility and improved brittleness, and when used as a polymer electrolyte membrane, the proton conductivity is higher than that of a conventional hydrocarbon polymer electrolyte membrane. And has the advantage of excellent durability.
In addition, the polymer electrolyte membrane of the present invention is excellent in bondability with the electrode catalyst layer, output characteristics and durability, and is a solid polymer type using a liquid such as methanol, dimethyl ether or formic acid or a gas such as hydrogen as the fuel. It can be suitably used for a fuel cell. Furthermore, it can be used for any known application as a polymer electrolyte membrane such as an electrolytic membrane and a separation membrane.

Hereinafter, the present invention will be described in detail.
The sulfonic acid group-containing polymer of the present invention is a polymer having at least structural units represented by Chemical Formula 1 and Chemical Formula 2. As for each structural unit, the same thing may be couple | bonded continuously and may be couple | bonded together randomly or alternately. N in Chemical Formula 1 and m in Chemical Formula 2 each independently represent an integer of 1 to 1000.

  The sulfonic acid group-containing polymer of the present invention more preferably has structural units represented by Chemical Formulas 3 and 4 in addition to the structural units represented by Chemical Formulas 1 and 2. As for each structural unit, the same thing may be couple | bonded continuously and may be couple | bonded together randomly or alternately. O in Chemical Formula 3 and m in Chemical Formula 4 each independently represent an integer of 1 to 1000.

  When the sulfonic acid group-containing polymer of the present invention has a structural unit represented by Chemical Formula 5 and Chemical Formula 6 in addition to the structural unit represented by Chemical Formula 1 and Chemical Formula 2, the chemical durability is improved. Therefore, it is more preferable. Furthermore, it is more preferable to have all the structural units represented by Chemical Formulas 1-6. As for each structural unit, the same thing may be couple | bonded continuously and may be couple | bonded together randomly or alternately. R in Chemical Formula 5 and s in Chemical Formula 6 each independently represent an integer of 1 to 1000.

X in the chemical formula 1, the chemical formula 3, and the chemical formula 5 represents a —S (═O) ₂ — group or a —C (═O) — group, and if it is a —S (═O) ₂ — group, This is preferable because of increased solubility. Moreover, it is preferable that it is -C (= O)-group since it becomes possible to give photocrosslinkability to a polymer. Y in Chemical Formula 1 represents H or a monovalent cation, but when used as a proton exchange membrane of a fuel cell, Y is preferably H. In processing such as dissolution, molding, and film formation, it is preferable that Y is a monovalent cation rather than H because the thermal stability of the sulfonic acid group is increased. Examples of monovalent cations include alkali metal ions such as Na, K and Li, ammonium ions and quaternary amine salts, and alkali metal ions such as Na, K and Li are preferred. . The sulfonic acid group that is an alkali metal salt can be converted to a sulfonic acid group by treating the polymer with a strong acid such as sulfuric acid, hydrochloric acid, perchloric acid, or an aqueous solution thereof. A polymer having a sulfonic acid group exhibits high proton conductivity, and can be used as a proton exchange resin or a proton exchange membrane. Among them, the proton exchange membrane can be used as an electrolyte of a polymer electrolyte fuel cell, and becomes an excellent polymer electrolyte membrane. R ¹ in Chemical Formula 1, Chemical Formula 3, and Chemical Formula 5 represents any one of a direct bond with an alkylene group having 1 to 10 carbon atoms, an oxyalkylene group, an arylene group, and a SO ₃ Y group, and is an alkylene group. And proton conductivity are improved. In addition, a direct bond in which a sulfonic acid group and a benzene ring are directly bonded is more preferable because stability of the sulfonic acid group with respect to heat, radicals, and the like is increased and proton conductivity is excellent. The alkylene group is preferably a straight chain rather than a branched one. As for carbon number of an alkylene group, 1-5 are more preferable, and 3-4 are more preferable. Specifically, an n-propylene group and an n-butylene group are preferable. 1-5 are more preferable and, as for carbon number of an oxyalkylene group, 3-4 are more preferable. Specifically, an oxy-n-propylene group and an oxy-n-butylene group are preferable. Examples of the arylene group include an oxyphenylene group and a phenylene group.

  In the structural unit represented by Chemical Formula 1, Chemical Formula 3, and Chemical Formula 5, the following chemical formula 12;

  Specific examples of the partial structure represented by formula (1) are shown below, but are not limited thereto, and include those in which a part and all of the sulfonic acid groups form a monovalent cation. . Of the following partial structures, chemical formulas 12A, 12B, 12C, and 12D are more preferable, and chemical formulas 12A and 12B are more preferable.

R ² in Formulas 1 and 2, an alkylene group or a sulfur atom, or 2 to 20 carbon atoms which may contain an oxygen atom is an aralkylene group, more alkylene groups are preferred. 4-10 are preferable and, as for carbon number, 4-6 are more preferable. The alkylene group is preferably a straight chain rather than a branched one. In R ² in Chemical Formula 1 and Chemical Formula 2, the alkylene group may contain a sulfur atom or an oxygen atom, but preferably does not contain or contains a sulfur atom, and more preferably does not contain it. In R ² in Chemical Formula 1, as the linear alkylene group, ethylene group, n-propylene group, n-butylene group, n-pentylene group, n-hexylene group, n-heptylene group, n-octylene group, n- Nonylene group, n-decylene group, 3,6-dioxaoctylene group, 3,7-dithianonylene group, 3-thia-n-pentylene group and the like can be mentioned as examples, but are not limited thereto. Absent. Among them, n-butylene group, n-pentylene group, n-hexylene group, n-heptylene group, n-octylene group, n-nonylene group, n-decylene group, 3,7-dithianonylene group, 3-thia-n-pentylene group Group is preferable, and n-butylene group, n-pentylene group and n-hexylene group are more preferable. In R ² in Chemical Formula 1 and Chemical Formula 2, examples of the branched alkylene group include 1-methylethylene group and 2,3-dihydroxy-n-butylene group, but are not limited thereto. In R ² in Chemical Formula 1 and Chemical Formula 2, an aralkylene group represents an aromatic group having an alkylene group at both ends, and examples thereof include an o-xylidene group, an m-xylidene group, and a p-xylidene group. It is not limited to.

Ar ¹ in chemical formulas 2, 4 and 6 represents a divalent aromatic group having an electron-withdrawing group. Examples of electron withdrawing groups include sulfone groups, carbonyl groups, sulfonyl groups, phosphine groups, cyano groups, trifluoromethyl groups and other perfluoroalkyl groups, nitro groups, halogen groups, etc., cyano groups, sulfone groups A carbonyl group is preferred. The aromatic group represents a group having an aromatic ring. Examples of the group having an aromatic ring include a phenylene group, a pyridylene group, a naphthylene group, and an anthranylene group. In Ar ¹ , groups having aromatic rings may be connected to each other with an electron-withdrawing group.

Examples of Ar ¹ in Chemical Formulas 2, 4, and 6 are shown below, but are not limited thereto.

More preferable examples of Ar ¹ in Chemical Formulas 2, 4, and 6 include structures represented by Chemical Formulas 7 to 10, among which a structure represented by Chemical Formula 9 or 10 is more preferable, and is represented by Chemical Formula 10. The structure is most preferred.

In Chemical Formula 3 and Chemical Formula 4, Z ¹ represents either an oxygen atom or a sulfur atom, Z ³ represents an oxygen atom, a sulfur atom, a —C (CH ₃ ) ₂ — group, a —C (CF ₃ ) ₂ — group, It represents either a —CH ₂ — group or a cyclohexylene group. It is preferable that Z ¹ is an oxygen atom because the cost and toxicity of the monomer do not increase, and coloring in the polymerization hardly occurs. It is preferable that Z ¹ is a sulfur atom rather than an oxygen atom because oxidation resistance is increased. Z ² is preferably an oxygen atom, a sulfur atom, a —C (CH ₃ ) ₂ — group, a —C (CF ₃ ) ₂ — group or a cyclohexylene group, more preferably an oxygen atom or a sulfur atom.

  In the chemical formula 3 and the chemical formula 4, the following chemical formula 14;

  Specific examples of the partial structure represented by are shown below, but are not limited thereto. Among them, the chemical formulas 14A, 14C, 14D, 14E, 14G, 14I, 14K, and 14M are preferable, the chemical formulas 14A, 14C, 14D, 14E, 14G, 14K, and 14M are more preferable, And 14M are more preferred.

In Chemical Formula 5 and Chemical Formula 6, Z ⁵ represents either a sulfur atom or an oxygen atom, and an oxygen atom is preferable because it is easy to obtain and synthesize monomers, and a sulfur atom is preferable for the oxidation resistance of the polymer. It is preferable because it improves. Ar ² represents a trivalent or tetravalent group containing an aromatic group, and examples thereof include a benzene ring, a naphthalene ring, a diphenylmethane group, and the like, and a phenyl ring is preferable. q is 1 or 2.

    In the chemical formulas 5 and 6, the following chemical formula 15;

Specific examples of the partial structure represented by are shown below, but are not limited thereto. Among these, chemical formula 15A is preferable.

  Although the preferable structure of the sulfonic acid group containing polymer of this invention is shown below, it is not necessarily limited to these. In the following chemical formula, each structural unit surrounded by () does not represent that they are bonded in the order of description, but represents a component constituting the polymer, and the same thing is continuous. They may be bonded together, or different structural units may be bonded randomly or alternately.

  In the chemical formulas 16 to 159, the subscripts A to P represent a combination of the structures of Ar and Ar1. Table 1 shows combinations of Ar and Ar1 structures for A to P.

  It is preferable that n, m, o, p, r, and s, which are the number of repeating structural units in the sulfonic acid group-containing polymer of the present invention, satisfy Formulas 1 to 3. When the sulfonic acid group-containing polymer of the present invention does not have the structural unit represented by Chemical Formula 3 and Chemical Formula 4, o and p are 0 in Formulas 1-3. In addition, when the sulfonic acid group-containing polymer of the present invention does not have the structural unit represented by Chemical Formula 5 and Chemical Formula 6, r and s are 0 in Formulas 1-3. .

0.05 ≦ (n + o + r) / (n + m + o + p + r + s) ≦ 0.70 (Formula 1)
0.01 ≦ (o + p) / (n + m + o + p + r + s) ≦ 0.99 (Formula 2)
0 ≦ (r + s) / (n + m + o + p + r + s) ≦ 0.10 (Formula 3)

  In Formula 1, when (n + o + r) / (n + m + o + p + r + s) is smaller than 0.05, proton conductivity is remarkably lowered when used as a polymer electrolyte membrane, which may be difficult to use as a fuel cell. Absent. When (n + o + r) / (n + m + o + p + r + s) is greater than 0.70, when a polymer electrolyte membrane is obtained, the swellability is remarkably increased and the mechanical strength and durability are lowered, which is not preferable. A more preferable range of (n + o + r) / (n + m + o + p + r + s) is a range of 0.05 to 0.50.

  In Formula 2, when (o + p) / (n + m + o + p + r + s) is smaller than 0.01, the solubility of the polymer and the stability of the polymer solution tend to be lowered. When (o + p) / (n + m + o + p + r + s) is larger than 0.99, proton conductivity and durability tend to be lowered when a polymer electrolyte membrane is formed. A more preferable range of (o + p) / (n + m + o + p + r + s) is 0.1 to 0.9, and a more preferable range is 0.2 to 0.8.

  In Formula 3, when (r + s) / (n + m + o + p + r + s) is larger than 0.10, only a polymer having a low polymerization degree may be obtained, and mechanical strength and durability tend to be lowered. A more preferable range of (r + s) / (n + m + o + p + r + s) is 0.001 to 0.07, and a more preferable range is 0.01 to 0.05.

  In Formula 4, when (n + m) / (n + m + o + p + r + s) is smaller than 0.01, the durability and proton conductivity improving effect when the polymer electrolyte membrane is formed tends to be too small. A more preferable range of (n + m) / (n + m + o + p + r + s) is 0.05 to 0.9, and a more preferable range is 0.1 to 0.8. When (n + m) / (n + m + o + p + r + s) is 1, the solubility of the polymer and the stability of the polymer solution may decrease.

  The sulfonic acid group-containing polymer of the present invention can be used for an ion exchange resin, a polymer electrolyte membrane, a moisture absorbent resin, a moisture absorbent membrane, a moisture permeable membrane, an electrolyte membrane, and the like, and particularly preferably used as a polymer electrolyte membrane. Furthermore, the polymer electrolyte membrane using the sulfonic acid group-containing polymer of the present invention can be used as a proton exchange membrane by converting the sulfonic acid group to a sulfonic acid type, and is particularly suitable for a proton exchange membrane for a fuel cell. . The sulfonic acid group-containing polymer of the present invention is also suitable for use as an adhesive when a polymer electrolyte membrane or the like is bonded to an electrode or a catalyst. When the sulfonic acid group-containing polymer of the present invention is used for a polymer electrolyte membrane or an adhesive for a polymer electrolyte membrane, Y is H (hydrogen ion) in the structural units represented by the chemical formulas 1, 3, and 5. It is preferable that

  When the polymer electrolyte membrane of the present invention is used in a fuel cell using a liquid such as methanol, formic acid, or ethanol as a fuel, the number of structural units in the sulfonic acid group-containing polymer of the present invention is n, m, o, p, r, and s preferably satisfy Formulas 5 to 8. When the sulfonic acid group-containing polymer of the present invention does not have the structural unit represented by Chemical Formula 3 and Chemical Formula 4, o and p are 0 in Formulas 5-8. In addition, when the sulfonic acid group-containing polymer of the present invention does not have the structural unit represented by Chemical Formula 5 and Chemical Formula 6, r and s are 0 in Formulas 5-8. .

  In Formula 5, when (n + o + r) / (n + m + o + p + r + s) is smaller than 0.05, proton conductivity is remarkably lowered, and use as a fuel cell may be difficult. When (n + o + r) / (n + m + o + p + r + s) is larger than 0.40, fuel permeability such as methanol is remarkably increased, and power generation output and efficiency tend to decrease. A more preferable range of (n + o + r) / (n + m + o + p + r + s) is 0.1 to 0.3.

  In Formula 6, when (o + p) / (n + m + o + p + r + s) is smaller than 0.10, the solubility of the polymer and the stability of the polymer solution may be lowered. When (o + p) / (n + m + o + p + r + s) is larger than 0.9, durability and proton conductivity may be lowered. A more preferable range of (o + p) / (n + m + o + p + r + s) is 0.2 to 0.9, and a more preferable range is 0.3 to 0.8.

  In Formula 7, when (r + s) / (n + m + o + p + r + s) is larger than 0.10, only a polymer having a low degree of polymerization may be obtained, and the mechanical strength and durability of the polymer electrolyte membrane tend to be lowered. A more preferable range of (r + s) / (n + m + o + p + r + s) is 0.001 to 0.07, and a more preferable range is 0.01 to 0.05.

  In Formula 8, when (n + m) / (n + m + o + p + r + s) is smaller than 0.1, the durability and proton conductivity improving effect of the polymer electrolyte membrane tends to be too small. When (n + m) / (n + m + o + p + r + s) is larger than 0.9, the solubility of the polymer and the stability of the polymer solution may be lowered. A more preferable range of (n + m) / (n + m + o + p + r + s) is 0.2 to 0.8, and a more preferable range is 0.2 to 0.5.

  When the polymer electrolyte membrane of the present invention is used in a fuel cell using a gas such as hydrogen as a fuel, n, m, o, p, which are the number of repeating structural units in the sulfonic acid group-containing polymer of the present invention. It is preferable that r and s satisfy Expressions 9 to 12. When the sulfonic acid group-containing polymer of the present invention does not have the structural unit represented by Chemical Formula 3 and Chemical Formula 4, o and p are 0 in Formulas 9-12. In addition, when the sulfonic acid group-containing polymer of the present invention does not have the structural unit represented by Chemical Formula 5 and Chemical Formula 6, r and s are 0 in Formulas 9-12. .

  In Expression 9, when (n + o + r) / (n + m + o + p + r + s) is smaller than 0.15, proton conductivity is remarkably lowered, and use as a fuel cell may be difficult. When (n + o + r) / (n + m + o + p + r + s) is larger than 0.70, the swellability is remarkably increased, and the power generation output and efficiency tend to decrease. A more preferable range of (n + o + r) / (n + m + o + p + r + s) is 0.15 to 0.50, and a more preferable range is 0.2 to 0.4.

  In Formula 10, when (o + p) / (n + m + o + p + r + s) is smaller than 0.01, the solubility of the polymer and the stability of the polymer solution may be lowered. When (o + p) / (n + m + o + p + r + s) is larger than 0.70, durability and proton conductivity may be lowered. A more preferable range of (o + p) / (n + m + o + p + r + s) is 0.1 to 0.7, and a more preferable range is 0.2 to 0.6.

  In Formula 11, when (r + s) / (n + m + o + p + r + s) is larger than 0.10, only a polymer having a low degree of polymerization may be obtained, and the mechanical strength and durability of the polymer electrolyte membrane tend to be lowered. A more preferable range of (r + s) / (n + m + o + p + r + s) is 0.01 to 0.07, and a more preferable range is 0.02 to 0.05.

  In Expression 12, when (n + m) / (n + m + o + p + r + s) is smaller than 0.05, the durability and proton conductivity improving effect of the polymer electrolyte membrane tends to be too small. When (n + m) / (n + m + o + p + r + s) is larger than 0.8, the solubility of the polymer and the stability of the polymer solution may be lowered. A more preferable range of (n + m) / (n + m + o + p + r + s) is 0.1 to 0.7, and a more preferable range is 0.2 to 0.6.

  The sulfonic acid group-containing polymer of the present invention can be dissolved and dispersed in an appropriate solvent and used as a composition. Solvents that can be used include N, N-dimethylformamide, N, N-dimethylacetamide, N, N-diethylacetamide, N-methyl-2-pyrrolidone, dimethyl sulfoxide, hexamethylphosphonamide, N-morpholine oxide, and the like. Polar solvents such as aprotic organic polar solvents, alcohol solvents such as methanol and ethanol, ketone solvents such as acetone, ether solvents such as diethyl ether, mixtures of these organic solvents, and mixtures with water However, it is not limited to these.

  The concentration of the polymer solution is preferably in the range of 0.1 to 50% by mass. When forming a film, fiber, or the like from a solution, the concentration is more preferably in the range of 5 to 50% by mass, and further preferably in the range of 10 to 40% by mass. When the solution is used as an adhesive, the concentration is more preferably in the range of 0.1 to 20% by mass. When the solution is used as an adhesive, it may contain other components such as carbon particles carrying a catalyst such as Pt and Pt—Ru, and a fluororesin.

  In the sulfonic acid group-containing polymer of the present invention, the structural unit represented by the chemical formulas 1 and 2 increases the flexibility of the polymer, suppresses breakage against deformation, improves durability, and lowers the glass transition temperature. It brings about effects such as improving the bondability. In addition, the structural units represented by the chemical formulas 3 and 4 can reduce the swelling property of the whole polymer, reduce the methanol permeability, improve the solubility of the polymer, and improve the stability of the polymer solution. Has an effect. The structural units represented by Chemical Formulas 1, 3, and 5 have the effect of imparting ionic conductivity and proton conductivity. The structural units represented by Chemical Formulas 5 and 6 have the effect of suppressing chemical deterioration and further improving durability.

  The sulfonic acid group-containing polymer of the present invention can be polymerized by an aromatic nucleophilic substitution reaction from a mixture of monomers containing compounds represented by chemical formulas 160 to 162 as essential components.

In Chemical Formula 160, X represents an —S (═O) ₂ — group or —C (═O) — group, R ³ represents an alkylene group having 1 to 10 carbon atoms, an oxyalkylene group, an arylene group, and a direct bond (benzene ring). And an SO ₃ Y group), an alkylene group is preferable because proton conductivity is improved. In addition, a direct bond in which a sulfonic acid group and a benzene ring are directly bonded is more preferable because stability of the sulfonic acid group with respect to heat, radicals, and the like is increased and proton conductivity is excellent. The alkylene group is preferably a straight chain rather than a branched one. As for carbon number of an alkylene group, 1-5 are more preferable, and 3-4 are more preferable. Specifically, an n-propylene group and an n-butylene group are preferable. 1-5 are more preferable and, as for carbon number of an oxyalkylene group, 3-4 are more preferable. Specifically, an oxy-n-propylene group and an oxy-n-butylene group are preferable. Examples of the arylene group include an oxyphenylene group and a phenylene group. Y represents H or a monovalent cation, and alkali metal ions such as Na, K, and Li are preferred. Z ⁴ represents one or more groups selected from the group consisting of a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, and a nitro group.

  Specific examples of the compound represented by Chemical Formula 160 include 3,3′-disulfo-4,4′-dichlorodiphenyl sulfone, 3,3′-disulfo-4,4′-difluorodiphenyl sulfone, and 3,3′-. Disulfo-4,4′-dichlorodiphenyl ketone, 3,3′-disulfo-4,4′-difluorodiphenyl sulfone, 3,3′-disulfobutyl-4,4′-dichlorodiphenyl sulfone, 3,3′-disulfobutyl- 4,4′-difluorodiphenyl sulfone, 3,3′-disulfobutyl-4,4′-dichlorodiphenyl ketone, 3,3′-disulfobutyl-4,4′-difluorodiphenyl sulfone, and their sulfonic acid groups are monovalent Examples include salts with cation species. The monovalent cation species may be sodium, potassium, other metal species, various amines, or the like, but is not limited thereto. Examples of the compound represented by the chemical formula 160 in which the sulfonic acid group is a salt include sodium 3,3′-disulfonate-4,4′-dichlorodiphenylsulfone, 3,3′-disulfonic acid. Sodium-4,4′-difluorodiphenylsulfone, sodium 3,3′-disulfonate-4,4′-dichlorodiphenylketone, sodium 3,3′-disulfonate-4,4′-difluorodiphenylsulfone, 3,3 'Sodium disulfonate-4,4'-difluorodiphenyl ketone, potassium 3,3'-disulfonate 4,4'-dichlorodiphenyl sulfone, potassium 3,3'-disulfonate 4,4'-difluorodiphenyl sulfone, 3, 3,3′-Disulfonic acid potassium 4,4′-dichlorodiphenyl ketone, 3,3′-disulfate Potassium phosphate 4,4'-difluoro diphenyl sulfone, 3,3'-like disulfonic acid potassium 4,4'-difluoro diphenyl ketone and the like.

In Chemical Formula 161, Ar ³ represents a divalent aromatic group having an electron-withdrawing group, and Z ⁵ represents one or more groups selected from the group consisting of a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, and a nitro group. To express. Examples of the electron withdrawing group in Ar ³ include a sulfo group, a carbonyl group, a sulfonyl group, a phosphine group, a perfluoroalkyl group such as a cyano group, a trifluoromethyl group, a nitro group, a halogen group, and the like. Group, sulfone group and carbonyl group are preferred. The aromatic group in Ar ³ represents a group having an aromatic ring. Examples of the group having an aromatic ring include a phenylene group, a pyridylene group, a naphthylene group, and an anthranylene group. In Ar ³ , groups having an aromatic ring may be linked with an electron-withdrawing group.

  Examples of the compound represented by Chemical Formula 161 include a compound having a leaving group in a nucleophilic substitution reaction such as halogen or nitro group and an electron-withdrawing group for activating it in the same aromatic ring. Specific examples include 2,6-dichlorobenzonitrile, 2,4-dichlorobenzonitrile, 2,6-difluorobenzonitrile, 2,4-difluorobenzonitrile, 4,4′-dichlorodiphenylsulfone, 4,4 ′. -Difluorodiphenyl sulfone, 4,4'-difluorobenzophenone, 4,4'-dichlorobenzophenone, decafluorobiphenyl, and the like, but not limited thereto, other aromatics active in aromatic nucleophilic substitution reaction A group dihalogen compound, an aromatic dinitro compound, an aromatic dicyano compound, and the like can also be used.

  Specific examples of the compound represented by Chemical Formula 161 are shown below, but are not limited thereto. Among them, the chemical formulas 161A, 161B, 161C, 161D, 161O, 161P, 161Q, and 161R are preferable, 161C, 161D, 161Q, and 161R are more preferable, and 161D and 161R are more preferable.

In Chemical Formula 162, R ⁴ represents an alkylene group or aralkylene group having 2 to 20 carbon atoms which may contain a sulfur atom or an oxygen atom, but an alkylene group is more preferable. 4-10 are preferable and, as for carbon number, 4-6 are more preferable. The alkylene group is preferably a straight chain rather than a branched one. In R ² in Chemical Formula 1 and Chemical Formula 2, the alkylene group may contain a sulfur atom or an oxygen atom, but preferably does not contain or contains a sulfur atom, and more preferably does not contain it. In R ⁴ in Chemical Formula 162, the linear alkylene group includes an ethylene group, an n-propylene group, an n-butylene group, an n-pentylene group, an n-hexylene group, an n-heptylene group, an n-octylene group, an n- Nonylene group, n-decylene group, 3,6-dioxaoctylene group, 3,7-dithianonylene group, 3-thia-n-pentylene group and the like can be mentioned as examples, but are not limited thereto. Absent. Among them, n-butylene group, n-pentylene group, n-hexylene group, n-heptylene group, n-octylene group, n-nonylene group, n-decylene group, 3,7-dithianonylene group, 3-thia-n-pentylene group Group is preferable, and n-butylene group, n-pentylene group and n-hexylene group are more preferable. In R ⁴ in Chemical Formula 162, examples of the branched alkylene group include, but are not limited to, 1-methylethylene group and 2,3-dihydroxy-n-butylene group. In R ⁴ in Chemical Formula 162, the aralkylene group represents an aromatic group having an alkylene group at both ends, and examples thereof include, but are not limited to, an o-xylidene group, an m-xylidene group, and a p-xylidene group. It is not something.

Z ⁶ in Chemical Formula 162 represents a mercapto group and derivatives thereof. Examples of the mercapto group derivative in Chemical Formula 162 include alkali metal salts such as Na, K, and Li, and carbamoylated compounds obtained by reaction with isocyanate compounds.

  Examples of the compound represented by Chemical Formula 162 include 1,2-ethanedithiol, 1,3-propanedithiol, 1,2-propanedithiol, 1,4-butanedithiol, 2,3-dihydroxy-1,4-butane. Dithiol, 1,5-pentanedithiol, 1,6-hexanedithiol, 1,7-heptanedithiol, 1,8-octanedithiol, 1,9-nonanedithiol, 1,10-decanedithiol, 1,11-undecanedithiol 1,12-dodecanedithiol, 1,13-tridecanedithiol, 1,14-tetradecanedithiol, 1,15-pentadecanedithiol, 1,16-hexadecanedithiol, 1,17-heptadecanedithiol, 1,18-octadecane Dithiol, 1,19-nonadecanedithiol, 1,20 Icosanedithiol, 3,6-dioxa-1,8-octanedithiol, 3,7-dithia-1,9-nonanedithiol, 3-thia-1,5-pentanedithiol, 2,3-dihydroxy-1,4 -Butanedithiol, 1,4-bis (mercaptomethyl) benzene, 1,3-bis (mercaptomethyl) benzene, 1,2-bis (mercaptomethyl) benzene, and the like, but are not limited thereto Instead, any compound can be used as long as it is within the range of chemical formula 162. Also,

  The sulfonic acid group-containing polymer of the present invention uses a compound represented by the following chemical formula 163 in addition to the compounds represented by the chemical formulas 160 to 162, so that the shape stability of the membrane when used as a polymer electrolyte membrane is increased. The solubility of the polymer, the stability of the polymer solution, etc. can be improved.

In Chemical Formula 163, Z ⁷ represents either an OH group or an SH group, Z ⁹ represents an oxygen atom, a sulfur atom, a —C (CH ₃ ) ₂ — group, a —C (CF ₃ ) ₂ — group, —CH _2. -Represents a group, a cyclohexylene group, or a direct bond. It is preferable that Z ⁷ is an OH group because synthesis and availability of the compound are easy. When Z ⁷ is an SH group, it is possible to improve the oxidation resistance of the obtained polymer, and it is preferable because a polymer having a high degree of polymerization is easily obtained because of high reactivity, but the resulting polymer is highly colored. There is a case. Z ⁹ is preferably an oxygen atom, a sulfur atom, a —C (CH ₃ ) ₂ — group, a —C (CF ₃ ) ₂ — group, a cyclohexylene group, or a direct bond, a sulfur atom, —C (CH ₃ ) _2. - group, -C _{(CF 3) 2} - group, cyclohexylene group, a direct bond (between the benzene ring) is more preferable. When Z ⁹ is a sulfur atom, —C (CH ₃ ) ₂ — group, —C (CF ₃ ) ₂ — group, or cyclohexylene group, the solubility of the polymer and the stability of the polymer solution can be improved. preferable. It is preferable that Z ⁹ is a direct bond because the morphological stability of the polymer electrolyte membrane can be improved.

  Specific examples of the compound represented by Formula 163 include 2,2-bis (4-hydroxyphenyl) propane, bis (4-hydroxyphenyl) methane, 2,2-bis (4-hydroxyphenyl) hexafluoropropane, 4 , 4′-thiobisbenzenethiol, 4,4′-oxybisbenzenethiol, bis (4-hydroxyphenyl) sulfide, 4,4′-dihydroxydiphenyl ether, 1,1-bis (4-hydroxyphenyl) cyclohexane, 4, , 4′-biphenol and the like, and 4,4′-thiobisbenzenethiol, bis (4-hydroxyphenyl) sulfide, 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis ( 4-hydroxyphenyl) hexafluoropropane, 1,1-bis (4-hydroxy) Eniru) cyclohexane, 4,4'-biphenol are preferable.

  The sulfonic acid group-containing polymer of the present invention enhances chemical durability by using not only the compounds represented by the chemical formulas 160 to 162 but also a compound having the structure represented by the following chemical formula 164 as one component of the monomer. be able to.

In Chemical Formula 164, Z ⁹ represents either an OH group or an SH group, but an OH group is preferable because it is easy to obtain and synthesize monomers, and an SH group improves the oxidation resistance of the polymer. preferable. Ar ⁴ represents a trivalent or tetravalent group containing an aromatic group, and examples thereof include a benzene ring, a naphthalene ring, and a diphenylmethane group, and a benzene ring is preferable. t is 1 or 2, and 1 is preferable.

  Although the preferable example of the structure represented by Chemical formula 164 is shown below, it is not limited to these. Of these, chemical formula 164A is preferred.

  The compounds represented by the chemical formulas 160 to 164 may be used by mixing a plurality of compounds within the range of the structure.

  In addition, other aromatic diol compounds or aromatic dithiol compounds can be used as one of the monomer components. Examples of other aromatic diol compounds or aromatic dithiol compounds include 9,9-bis (4-hydroxyphenyl) fluorene, 9,9-bis (3-methyl-4-hydroxyphenyl) fluorene, bis (4- Hydroxyphenyl) sulfone, 1,1-bis (4-hydroxyphenyl) ethane, 2,2-bis (4-hydroxyphenyl) butane, 3,3-bis (4-hydroxyphenyl) pentane, 2,2-bis ( 4-hydroxy-3,5-dimethylphenyl) propane, bis (4-hydroxy-3,5-dimethylphenyl) methane, bis (4-hydroxy-2,5-dimethylphenyl) methane, bis (4-hydroxyphenyl) Phenylmethane, hydroquinone, resorcin, bis (4-hydroxyphenyl) ketone, 1,4-benzenedithio 1,3-benzenedithiol, phenolphthalein, 4-ethylresorcinol, 4-hexylresorcinol, 2-hexylhydroquinone, 2-octylhydroquinone, 2-octadecylhydroquinone, 2-tertiarybutylhydroquinone, 2,5 -Ditertiary butyl hydroquinone, 2,5-ditertiary amyl hydroquinone, 2,2'-dihexyl-4,4'-dihydroxybiphenyl, 1-octyl-2,6-dihydroxynaphthalene, 2-hexyl-1,5-dihydroxy In addition to these, various aromatic diols or various aromatic dithiols that can be used for the polymerization of polyarylene ether compounds by aromatic nucleophilic substitution reaction can also be used. Limited Not.

  When the sulfonic acid group-containing polymer in the present invention is polymerized by an aromatic nucleophilic substitution reaction, a compound having a structure represented by chemical formulas 160 to 164, and other activated dihalogen aromatic compounds or dinitroaromatic compounds as necessary. And aromatic diols or aromatic dithiols can be added and reacted in the presence of a basic compound to obtain a polymer. The polymerization degree of the resulting polymer is adjusted by adjusting the molar ratio of the total of reactive halogen groups or nitro groups and the total of reactive hydroxy groups and thiol groups in the monomer to an arbitrary molar ratio. However, it is preferably 0.8 to 1.2, more preferably 0.9 to 1.1, and preferably 0.95 to 1.05. It is most preferable because a polymer having a high degree of polymerization can be obtained.

  The polymerization can be carried out in the temperature range of 0 to 350 ° C, but preferably in the range of 50 to 250 ° C. When the temperature is lower than 0 ° C., the reaction does not proceed sufficiently, and when the temperature is higher than 350 ° C., the polymer tends to be decomposed. The reaction can be carried out in the absence of a solvent, but is preferably carried out in a solvent. Examples of the solvent that can be used include N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, dimethyl sulfoxide, diphenyl sulfone, sulfolane, and the like. And any solvent that can be used as a stable solvent in the aromatic nucleophilic substitution reaction. These organic solvents may be used alone or as a mixture of two or more.

Examples of basic compounds include sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, etc., but activate aliphatic dithiols, aromatic diols, and aromatic dimercapto compounds. Any phenoxide structure can be used without limitation. The basic compound can be polymerized satisfactorily when used in an amount of 100 mol% or more based on the total number of moles of the aliphatic dithiol compound, aromatic diol compound, and aromatic dithiol compound, preferably It is the range of 105-125 mol% with respect to the sum total of each mole number of aliphatic dithiols, aromatic diol compounds, and aromatic dithiol compounds. If it is more than 125 mol%, it may cause side reactions such as decomposition, which is not preferable, and if it is less than 100 mol%, the reaction may not be allowed to proceed sufficiently.

  In the above polymerization reaction, an aliphatic dithiol, an aromatic diol compound, and an aromatic dithiol compound reacted with an isocyanate compound without using a basic compound and carbamoylated, and an activated dihalogen aromatic compound Or an activated dinitroaromatic compound can be directly reacted.

  In the aromatic nucleophilic substitution reaction, water may be generated as a by-product. In this case, regardless of the polymerization solvent, water can be removed from the system as an azeotrope by coexisting toluene or the like in the reaction system. As a method for removing water out of the system, a water absorbing material such as molecular sieve can also be used. When an aliphatic dithiol having a boiling point of 250 ° C. or lower is used, it is preferably reacted under reflux to prevent evaporation, and a dehydrating agent such as molecular sieve is preferably added to the reaction solution. When the aromatic nucleophilic substitution reaction is carried out in a solvent, it is preferable to charge the monomer so that the resulting polymer concentration is in the range of 5 to 50% by mass. When the amount is less than 5% by mass, the degree of polymerization tends to be difficult to increase. On the other hand, when the amount is more than 50% by mass, the viscosity of the reaction system becomes too high, and the post-treatment of the reaction product tends to be difficult. After completion of the polymerization reaction, the solvent is removed from the reaction solution by evaporation, and the residue is washed as necessary to obtain the desired polymer. In addition, the polymer can be obtained by precipitating the polymer as a solid by adding the reaction solution in a solvent having low polymer solubility, and collecting the precipitate by filtration. In addition, a polymer solution can be obtained by removing by-product salts by filtration.

  In addition, the sulfonic acid group-containing polymer in the present invention preferably has a polymer log viscosity measured by a method described later of 0.1 dL / g or more. When the logarithmic viscosity is less than 0.1 dL / g, the membrane tends to become brittle when molded as a polymer electrolyte membrane. The logarithmic viscosity is more preferably 0.3 dL / g or more. On the other hand, when the logarithmic viscosity exceeds 5 dL / g, problems in processability such as difficulty in dissolving the polymer occur, which is not preferable. As a solvent for measuring the logarithmic viscosity, polar organic solvents such as N-methylpyrrolidone and N, N-dimethylacetamide can be generally used. When the solubility in these is low, concentrated sulfuric acid is used. It can also be measured.

  The ion exchange capacity of the sulfonic acid group-containing polymer in the present invention is preferably 0.1 meq / g or more, more preferably 3.5 meq / g or less. A small ion exchange capacity is not preferable because proton conductivity decreases. As the ion exchange capacity increases, proton conductivity increases, but at the same time, problems such as membrane swelling and water dissolution are likely to occur. The ion exchange capacity of the sulfonic acid group-containing polymer in the present invention is more preferably in the range of 0.3 to 3.5 meq / g, and further preferably in the range of 0.4 to 2.5 meq / g.

  The polymer electrolyte membrane in the present invention can have any thickness, but if it is 10 μm or less, it becomes difficult to satisfy the predetermined characteristics, and therefore it is preferably 10 μm or more, and more preferably 20 μm or more. Moreover, since manufacture will become difficult when it becomes 300 micrometers or more, it is preferable that it is 300 micrometers or less.

  The sulfonic acid group-containing polymer in the present invention can be used as a simple substance, but can also be used as a resin composition in combination with other polymers. Examples of these polymers include polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, polyamides such as nylon 6, nylon 66, nylon 610, and nylon 12, polymethyl methacrylate, polymethacrylates, and polymethyl. Acrylate resins such as acrylates and polyacrylates, polyacrylic acid resins, polymethacrylic acid resins, polyethylene, polypropylene, various polyolefins including polystyrene and diene polymers, polyurethane resins, cellulose acetate, cellulose such as ethyl cellulose Resin, polyarylate, aramid, polycarbonate, polyphenylene sulfide, polyphenylene oxide, polysulfone, polyethers Thermal curing of aromatic polymers such as phon, polyetheretherketone, polyetherimide, polyimide, polyamideimide, polybenzimidazole, polybenzoxazole, polybenzthiazole, epoxy resin, phenol resin, novolac resin, benzoxazine resin There are no particular restrictions on the conductive resin. A resin composition with a basic polymer such as polybenzimidazole or polyvinylpyridine can be said to be a preferable combination for improving the polymer dimensionality, and when a sulfonic acid group is further introduced into these basic polymers, The processability of the composition becomes more preferable. When used as these resin compositions, the sulfonic acid group-containing polymer of the present invention is preferably contained in an amount of 50% by mass or more and less than 100% by mass of the entire resin composition. More preferably, it is 70 mass% or more and less than 100 mass%. When the content of the sulfonic acid group-containing polymer of the present invention is less than 50% by mass of the entire resin composition, the sulfonic acid group concentration of the polymer electrolyte membrane containing this resin composition is lowered and good ion conductivity is obtained. In addition, the unit containing a sulfonic acid group tends to be a discontinuous phase, and the mobility of ions to be conducted tends to decrease. In addition, the composition of the present invention, if necessary, for example, an antioxidant, a heat stabilizer, a lubricant, a tackifier, a plasticizer, a crosslinking agent, a viscosity modifier, an antistatic agent, an antibacterial agent, an antifoaming agent, Various additives such as a dispersant and a polymerization inhibitor may be included.

  The polymer electrolyte membrane of the present invention can be obtained from the composition containing the sulfonic acid group-containing ion exchange resin of the present invention by any method such as extrusion, rolling or casting. Among these, it is preferable to mold from a solution dissolved in an appropriate solvent. A method of obtaining a molded body from a solution can be performed using a conventionally known method. For example, the molded product can be obtained by removing the solvent by heating, drying under reduced pressure, immersion in a compound non-solvent that can be mixed with a solvent that dissolves the compound, or the like. When the solvent is an organic solvent, the solvent is preferably distilled off by heating or drying under reduced pressure. At this time, if necessary, it can be molded in a form combined with other compounds. When combined with a compound having a similar dissolution behavior, it is preferable in that good molding can be achieved. The sulfonic acid group in the molded article thus obtained may contain a salt form with a cationic species, but it is converted to a free sulfonic acid group by acid treatment if necessary. You can also.

  The most preferable method for forming a polymer electrolyte membrane from a sulfonic acid group-containing polymer and a resin composition thereof in the present invention is casting from a solution, and the polymer is removed from the cast solution by removing the solvent as described above. An electrolyte membrane can be obtained. Examples of the solution include a solution using an organic solvent such as N-methylpyrrolidone, N, N-dimethylformamide, and dimethyl sulfoxide, and in some cases, an alcohol solvent. The removal of the solvent is preferably by drying in view of the uniformity of the polymer electrolyte membrane. Moreover, in order to avoid decomposition | disassembly and alteration of a compound or a solvent, it can also dry at the lowest temperature possible under reduced pressure. Further, when the viscosity of the solution is high, when the substrate or the solution is heated and cast at a high temperature, the viscosity of the solution is lowered and the casting can be easily performed. The thickness of the solution at the time of casting is not particularly limited, but is preferably in the range of 10 to 2000 μm. More preferably, it is 50-1500 micrometers. If the thickness of the solution is less than 10 μm, the form as a polymer electrolyte membrane tends to be not maintained, and if it is more than 2000 μm, a non-uniform film tends to be easily formed. As a method for controlling the cast thickness of the solution, a known method can be used. For example, the thickness can be controlled by the amount and concentration of the solution by making the thickness constant using an applicator, a doctor blade or the like, or making the cast area constant using a glass petri dish or the like. The cast solution can obtain a more uniform film by adjusting the solvent removal rate. For example, in the case of heating, the evaporation rate can be reduced by lowering the temperature in the first stage. In addition, when immersed in a non-solvent such as water, the coagulation rate of the compound can be adjusted by leaving the solution in air or an inert gas for an appropriate time. When used as a polymer electrolyte membrane, the sulfonic acid group in the membrane may contain a metal salt, but can be converted to free sulfonic acid by an appropriate acid treatment. In this case, it is also effective to immerse the membrane in an aqueous solution of sulfuric acid, hydrochloric acid or the like with or without heating.

The membrane / electrode assembly of the present invention can be obtained by bonding the polymer electrolyte membrane of the present invention to an electrode.
An electrode consists of an electrode material and a layer (electrode catalyst layer) containing a catalyst formed on the surface thereof, and a known material can be used as the electrode material. For example, a conductive porous material such as carbon paper or carbon cloth can be used, but is not limited thereto. As the conductive porous material such as carbon paper or carbon cloth, a material subjected to surface treatment such as water repellent treatment or hydrophilic treatment can be used. A known material can be used for the catalyst. For example, platinum, an alloy of platinum and ruthenium, and the like can be given, but the invention is not limited to them.
The catalyst can be used in any known form, and for example, carbon particles carrying catalyst fine particles can be used, but are not limited thereto.
An adhesive can be used for the catalyst and the electrode catalyst layer including the particles carrying the catalyst, and as the adhesive, a resin having proton conductivity can be used.

  As a method for producing this joined body, a conventionally known method can be used. For example, a method of applying an adhesive to the electrode surface and bonding the polymer electrolyte membrane and the electrode, or a polymer electrolyte membrane and the electrode There is a method of heating and pressurizing. As the adhesive, a known material such as a Nafion (trade name) solution may be used, or an adhesive mainly composed of the same polymer composition as that of the polymer constituting the polymer electrolyte membrane of the present invention may be used. However, other hydrocarbon-based proton conductive polymers may be used as the main component. A catalyst such as platinum or platinum-ruthenium alloy necessary for the electrode reaction can be obtained by dispersing the catalyst supported on conductive particles such as carbon in the adhesive. . The method for producing a joined body of an electrode and a polymer electrolyte membrane is preferably a method of applying and bonding to the electrode surface. Since the polymer electrolyte membrane and the polymer composition of the present invention have an appropriate softening temperature, they are particularly suitable for a method of joining a polymer electrolyte membrane and an electrode by pressure heating.

  The fuel cell of the present invention can be produced using the polymer electrolyte membrane or the polymer electrolyte membrane / electrode assembly of the present invention. The fuel cell of the present invention includes, for example, an oxygen electrode, a fuel electrode, a polymer electrolyte membrane sandwiched between the electrodes, an oxidant flow path provided on the oxygen electrode side, and a fuel electrode side. The fuel flow path is provided. A fuel cell stack can be obtained by connecting such unit cells with a conductive separator.

EXAMPLES Hereinafter, although this invention is demonstrated concretely using an Example, this invention is not limited to these Examples. Various measurements were performed as follows.
<Logarithmic viscosity>
The polymer powder was dissolved in N-methylpyrrolidone at a concentration of 0.5 g / dL, the viscosity was measured using a Ubbelohde viscometer in a constant temperature bath at 30 ° C., and the logarithmic viscosity ln [ta / tb] / c was evaluated. (Ta is the drop time of the sample solution, tb is the drop time of the solvent only, and c is the polymer concentration).

<Proton conductivity>
A platinum wire (diameter: 0.2 mm) is pressed on the surface of the strip-shaped membrane sample on a probe for self-made measurement (made of tetrafluoroethylene resin) and placed in water at 25 ° C. or in a constant temperature and humidity chamber at 80 ° C. and 95% RH. The sample was held, and the impedance between the platinum wires was measured by SOLARTRON 1250 FREQUENCY RESPONSE ANALYSER. The measurement was performed while changing the distance between the electrodes, and the conductivity obtained by canceling the contact resistance between the film and the platinum wire was calculated from the gradient obtained by plotting the distance measured between the electrodes and the resistance measurement value estimated from the CC plot.
Conductivity [S / cm] = 1 / film width [cm] × film thickness [cm] × resistance interelectrode gradient [Ω / cm]

<Methanol permeability>
The liquid fuel permeation rate of the polymer electrolyte membrane was measured as the methanol permeation rate by the following method. A polymer electrolyte membrane immersed in a 5 M (mol / liter) aqueous methanol solution adjusted to 25 ° C. for 24 hours is sandwiched between H-type cells, 100 mL of 5 M aqueous methanol solution is added to one side of the cell, and 100 mL of the other cell is over 100 mL. Inject pure water (18 MΩ · cm) and measure the amount of methanol diffusing into ultrapure water through the polymer electrolyte membrane while stirring the cells on both sides at 25 ° C using a gas chromatograph. (The area of the polymer electrolyte membrane was 2.0 cm ² ). A methanol permeability coefficient was determined from the obtained methanol permeation rate and the film thickness of the sample.

<Power generation evaluation of hydrogen-fueled fuel cell (PEFC)>
After adding 40% Pt catalyst-supporting carbon (catalyst for fuel cell manufactured by Tanaka Kikinzoku Kogyo Co., Ltd .: TEC10V40E), a small amount of ultrapure water and isopropanol, to DuPont 20% Nafion (registered trademark) solution, until uniform Stir to prepare a catalyst paste. This catalyst paste was uniformly applied to carbon paper (TGPH-060 manufactured by Toray Industries, Inc.) so that the amount of platinum deposited was 0.5 mg / cm ² and dried to prepare a gas diffusion layer with an electrode catalyst layer. By sandwiching the polymer electrolyte membrane between the gas diffusion layers with the electrode catalyst layer so that the electrode catalyst layer is in contact with the membrane, and pressurizing and heating at 5 MPa for 3 minutes by a hot press method, the membrane-electrode A joined body was obtained. The heating temperature was appropriately adjusted to a temperature at which peeling between the electrode catalyst layer and the membrane did not occur for each polymer electrolyte membrane used for evaluation. This joined body is incorporated into an evaluation fuel cell FC25-02SP manufactured by Electrochem, and at a cell temperature of 80 ° C., hydrogen humidified at 75 ° C. to the anode and air humidified at 75 ° C. to the cathode are supplied to generate electricity. The characteristics were evaluated. The output voltage at a current density of 0.5 A / cm ² immediately after the start was taken as the initial characteristics. Moreover, as durability evaluation, the continuous operation was performed on said conditions, measuring an open circuit voltage 3 times per hour. The time when the open circuit voltage decreased by 10% or more from the value immediately after the start was defined as the endurance time. Durability evaluation was performed with 2000 hours as the upper limit.

<Power generation evaluation of direct methanol fuel cell (DMFC)>
After adding a small amount of ultrapure water and isopropyl alcohol to a Pt / Ru catalyst-supporting carbon (TEC61E54 manufactured by Tanaka Kikinzoku Kogyo Co., Ltd.) and moistening, a 20% Nafion (registered trademark) solution (product number: SE-20192) manufactured by DuPont is used. The Pt / Ru catalyst-carrying carbon and Nafion (registered trademark) were added at a mass ratio of 2.5: 1. Next, stirring was performed to prepare an anode catalyst paste. This catalyst paste is applied to a carbon paper (TGPH-060 manufactured by Toray Industries, Inc.) serving as a gas diffusion layer by screen printing so that the amount of platinum deposited is 2 mg / cm ^2, and then carbon paper with an electrode catalyst layer for an anode. Was made. Moreover, after adding a small amount of ultrapure water and isopropyl alcohol to a Pt catalyst-supporting carbon (Tanaka Kikinzoku Kogyo TEC10V40E) and moistening, a 20% Nafion (registered trademark) solution (product number: SE-20192) manufactured by DuPont, A cathode catalyst paste was prepared by adding Pt catalyst supporting carbon and Nafion (registered trademark) so that the mass ratio was 2.5: 1 and stirring. The catalyst paste was applied and dried on carbon paper (TGPH-060 manufactured by Toray Industries, Inc.) subjected to water repellent treatment so that the amount of platinum deposited was 1 mg / cm ^2. Produced. A membrane sample is sandwiched between the above two types of carbon paper with an electrode catalyst layer so that the electrode catalyst layer is in contact with the membrane sample, and heated and pressurized at 5 MPa for 3 minutes by a hot press method, whereby a membrane-electrode is obtained. A joined body was obtained. The heating temperature was appropriately adjusted to a temperature at which peeling between the electrode catalyst layer and the membrane did not occur for each polymer electrolyte membrane used for evaluation. This joined body was incorporated into an evaluation fuel cell FC25-02SP manufactured by Electrochem, and a power generation test was performed using a fuel cell power generation tester (manufactured by Toyo Corporation). For power generation, a 5 mol / L methanol aqueous solution (1.5 ml / min) adjusted to 40 ° C. at the cell temperature and a high-purity air gas (80 ml / min) adjusted to 40 ° C. at the cathode, respectively. It went while supplying. The output voltage at a current density of 0.05 A / cm ² was measured.

<Ion exchange capacity>
The weight of a sample dried at 100 ° C. for 1 hour and allowed to stand overnight at room temperature in a nitrogen atmosphere was weighed, stirred with an aqueous sodium hydroxide solution, and then ion exchange capacity was determined by back titration with an aqueous hydrochloric acid solution.

<Synthesis Example 1>
Sodium 3,3′-disulfonate-4,4′-dichlorodiphenylsulfone (abbreviation: SDS) 25.00 g, 2,6-dichlorobenzonitrile (abbreviation: DCB) 64.19 g, 1,6-hexanedithiol (abbreviation) : HDT) 63.74 g, potassium carbonate 64.47 g, and dried molecular sieve 3-A 60 g were weighed into a 2000 mL four-necked flask equipped with a cooling reflux tube and flushed with nitrogen at 0.5 L / min. Add 400 ml of N-methyl-2-pyrrolidone (abbreviation: NMP), put in oil bath, stir oil bath temperature at 150 ° C. for 30 minutes, then set oil bath temperature at 215 ° C. and react for 12 hours. I let you. After allowing to cool, the precipitated molecular sieve was removed by filtration through a 1G25 glass filter, and the polymerization solution was precipitated in water into a strand. The obtained polymer was washed 6 times with normal temperature water and dried at 110 ° C.

<Synthesis Examples 2-20>
The polymers of Synthesis Examples 2 to 20 were synthesized in the same manner as in Synthesis Example 1 except that each monomer component and the molar ratio thereof were changed. Potassium carbonate was used in an amount that would be 10% excess relative to the total number of moles of the aliphatic dithiol compound, aromatic diol compound, and aromatic dithiol compound. The molecular sieve was used in approximately the same amount as potassium carbonate. NMP was used in an amount of about 2.6 times the mass of the calculated polymer amount.

<Comparative Synthesis Examples 1 to 4> The polymers of Comparative Synthesis Examples 1 to 7 were synthesized in the same manner as Synthesis Example 1 except that the molar ratio was changed. Potassium carbonate was used in an amount that would be 10% excess relative to the total number of moles of aromatic diol compound. The molecular sieve was used in approximately the same amount as potassium carbonate. NMP was used in an amount of about 2.6 times the mass of the calculated polymer amount.

<Synthesis Example 21>
50.00 g of SDS, 45.02 g of DCB, 1,10-decanedithiol (abbreviation: DDT) 15.01 g, BP 54.15 g, 53.76 g of potassium carbonate, 60 g of dried molecular sieve 3-A were attached to a cooling reflux tube. Weighed into a 2000 mL four-necked flask and flushed with nitrogen at 0.5 L / min. Add 320 ml of N-methyl-2-pyrrolidone (abbreviation: NMP), put it in an oil bath, stir the oil bath at 150 ° C. for 30 minutes, then set the oil bath temperature at 215 ° C. and react for 12 hours. I let you. After allowing to cool, the precipitated molecular sieve was removed by filtration through a 1G25 glass filter, and the polymerization solution was precipitated in water into a strand. The obtained polymer was washed 6 times with normal temperature water and dried at 110 ° C.
Table 2 shows the compositions and logarithmic viscosities of the polymers of Synthesis Examples 1 to 21 and Comparative Synthesis Examples 1 to 4. The abbreviations in Table 2 represent the following compounds.
SDS: sodium 3,3′-disulfonate-4,4′-dichlorodiphenylsulfone SBP: sodium 3,3′-disulfonate-4,4′-dichlorobenzophenone DCB: 2,6-dichlorobenzonitrile DCS: 4, 4'-dichlorodiphenyl sulfone CBP: 4,4'-dichlorobenzophenone HDT: 1,6-hexanedithiol DDT: 1,10-decanedithiol NDT: 3,6-dithia-1,9-nonanedithiol PDT: 2-mercapto Ethyl sulfide XDT: 1,4-bis (mercaptomethyl) benzene BDT: 2,3-dihydroxy-1,4-butanedithiol BPS: Bis (4-hydroxyphenyl) sulfide BP: 4,4′-biphenol TBT: 4, 4′-thiobisbenzenethiol DHE: 4,4′-di Droxydiphenyl ether BPA: 2,2-bis (4-hydroxyphenyl) propane BPF: 2,2-bis (4-hydroxyphenyl) hexafluoropropane BPH: 1,1-bis (4-hydroxyphenyl) cyclohexane DHM: 4 , 4'-dihydroxydiphenylmethane HCQ: 10- (2,5-dihydroxyphenyl) -9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide

  The polymer structures represented by chemical formulas 166 to 168 in Table 2 are shown below.

<Examples 1 to 21>
About each of the polymers obtained in Synthesis Examples 1 to 21, 7 g was dissolved in 28 g of NMP, cast on a glass plate on a hot plate to a thickness of about 400 μm, cast at 80 ° C. for 0.5 hours, 120 ° C. for 0.5 hours, 150 After heating at 50 ° C. for 0.5 hour, the film was dried in an oven at 150 ° C. in a nitrogen atmosphere for 1 hour to peel the film from the glass plate. The obtained film was immersed in pure water at room temperature for 1 day, then immersed in a 2 mol / L sulfuric acid aqueous solution for 1 hour, and further immersed in another 2 mol / L sulfuric acid aqueous solution for 1 hour. Then, the film is washed with pure water until the washing water becomes neutral, the surface moisture is removed with filter paper, and then sandwiched between clean filter papers. The polymer electrolyte membrane was obtained by leaving it to dry. The obtained polymer electrolyte membrane was evaluated.
<Comparative Examples 1-4>
About the polymer obtained by the synthesis examples 1-4, it carried out similarly to the Example, and obtained the polymer electrolyte membrane. The obtained polymer electrolyte membrane was evaluated. In power generation evaluation of Comparative Examples 2 to 4, the polymer electrolyte membrane was previously left in an atmosphere at 25 ° C. and 100% RH for 1 hour, and then hot pressed to produce a membrane / electrode assembly.
The evaluation results are shown in Table 3.

  From Table 3, the polymer electrolyte membrane (Examples 17 to 21) for the fuel cell (PEFC) using hydrogen as a fuel in the present invention is the polymer electrolyte membrane of the comparative example (Comparative Examples 3 to 4). The initial voltage is equivalent to that of the membrane, but the durability time is greatly improved, indicating that the membrane is an excellent polymer electrolyte membrane. In the present invention, the polymer electrolyte membranes (Examples 1 to 16) for direct methanol fuel cells (DMFC) have an output voltage higher than that of the comparative polymer electrolyte membranes (Comparative Examples 1 and 2). It is clear that the polymer electrolyte membrane is high and excellent. In addition, the polymer electrolyte membrane of the present invention exhibits high proton conductivity as compared with the polymer electrolyte membrane of the comparative example having the same ion exchange capacity, and contributes to high output of the fuel cell. In addition, the polymer electrolyte membrane of the present invention can favorably bond the membrane and the electrode at a moderate temperature of 110 to 160 ° C., and is excellent in handleability.

  The sulfonic acid group-containing polymer of the present invention has improved polymer flexibility and improved brittleness, and when it is used as a polymer electrolyte membrane, it has proton conductivity and is higher than that of a conventional hydrocarbon polymer electrolyte membrane. Since it has the advantage of being excellent in durability, it is useful as a polymer electrolyte membrane for fuel cells. Furthermore, it can be used for any known application as a polymer electrolyte membrane such as an electrolytic membrane and a separation membrane. It is possible to contribute to the industry.

Claims (21)

A sulfonic acid group-containing polymer having at least a structural unit represented by the following chemical formulas 1 and 2.


[In Chemical Formulas 1 and 2, X represents an —S (═O) ₂ — group or —C (═O) — group, Y represents H or a monovalent cation, and R ¹ represents an alkylene having 1 to 10 carbon atoms. Any one of a group, an oxyalkylene group, an arylene group and a direct bond (with a benzene ring and a SO ₃ Y group), R ² is an alkylene having 2 to 20 carbon atoms which may contain a sulfur atom or an oxygen atom. A group or an aralkylene group, Ar ¹ represents a divalent aromatic group having an electron-withdrawing group, and n and m represent an integer of 1 to 1000 in terms of the number of moles of each structural unit in the polymer molecule. ] The sulfonic acid group-containing polymer according to claim 1, further comprising structural units represented by the following chemical formulas 3 and 4.

[In the chemical formulas 3 and 4, X represents an —S (═O) ₂ — group or —C (═O) — group, Y represents H or a monovalent cation, and R ¹ represents an alkylene having 1 to 10 carbon atoms. Any one of a group, an oxyalkylene group, an arylene group and a direct bond (a benzene ring and an SO ₃ Y group), Ar ¹ is a divalent aromatic group having an electron-withdrawing group, and Z ¹ is oxygen Either an atom or a sulfur atom, Z ² is an oxygen atom, a sulfur atom, a —C (CH ₃ ) ₂ — group, a —C (CF ₃ ) ₂ — group, a —CH ₂ — group, a cyclohexylene group, a direct In any of the bonds (between benzene rings), o and p each represents an integer of 1 to 1000 in terms of the number of moles of each structural unit in the polymer molecule. ] The sulfonic acid group-containing polymer according to claim 1 or 2, further comprising structural units represented by the following chemical formulas 5 and 6.
[In Chemical Formulas 5 and 6, X represents an —S (═O) ₂ — group or —C (═O) — group, Y represents H or a monovalent cation, and R ¹ represents an alkylene having 1 to 10 carbon atoms. Any one of a group, an oxyalkylene group, an arylene group, and a direct bond (a benzene ring and a SO ₃ Y group), Ar ¹ is a divalent aromatic group having an electron-withdrawing group, and Z ³ is Either an oxygen atom or a sulfur atom, Ar ² is a trivalent or tetravalent group containing an aromatic group, q is 1 or 2, and r and s are the number of moles of each structural unit in the polymer molecule. The integer of 1-1000 is represented. ] The sulfonic acid group-containing polymer according to claim 1, wherein Ar ¹ in Chemical Formulas 2, 4 and 6 is at least one of structural units represented by Chemical Formulas 7 to 10 below.


The sulfonic acid group-containing polymer according to any one of claims 1 to 3, wherein Ar ¹ in Chemical Formulas 2, 4, and 6 is any one of the structural units represented by Chemical Formula 9 or 10. The sulfonic acid group-containing polymer according to claim 1, wherein R ¹ in the chemical formulas 1, 3, 5 and 12 is a direct bond with an SO ₃ Y group. Sulfonic acid group-containing polymer according to claim 1 to 3 R ² is a linear alkylene group in Chemical Formula 1 and 2. The sulfonic acid group-containing polymer according to claim 2, wherein Z ¹ in Chemical Formulas 3 and 4 is an oxygen atom. The sulfonic acid group-containing polymer according to claim 2, wherein Z ² in Chemical Formulas 3 and 4 is a direct bond of a benzene ring. 3. The sulfonic acid group-containing polymer according to claim 2, wherein Z ² in Chemical Formulas 3 and 4 is any one of —C (CH ₃ ) ₂ — group, —C (CF ₃ ) ₂ — group, and cyclohexylene group. . The sulfonic acid group-containing polymer according to claim 3, wherein Z ³ in Chemical Formulas 5 and 6 is an oxygen atom. The sulfonic acid group-containing polymer according to claim 3, wherein Ar ² in Chemical Formulas 3 and 4 is a benzene ring.   The sulfonic acid group-containing polymer according to claim 3, wherein q in Chemical Formulas 5 and 6 is 1. The sulfonic acid group-containing polymer according to claim 1, wherein n, m, o, p, r, and s in chemical formulas 1 to 6 satisfy the following formulas 1 to 3.
0.05 ≦ (n + o + r) / (n + m + o + p + r + s) ≦ 0.70 (Formula 1)
0.01 ≦ (o + p) / (n + m + o + p + r + s) ≦ 0.99 (Formula 2)
0 ≦ (r + s) / (n + m + o + p + r + s) ≦ 0.10 (Formula 3)
0.01 ≦ (n + m) / (n + m + o + p + r + s) ≦ 1.00 (Formula 4)   A polymer electrolyte membrane comprising the sulfonic acid group-containing polymer according to claim 1. 16. The polymer electrolyte membrane according to claim 15, wherein n, m, o, p, r, and s in chemical formulas 1 to 6 satisfy the following formulas 4 to 6 and are used for direct methanol fuel cells.
0.05 ≦ (n + o + r) / (n + m + o + p + r + s) ≦ 0.40 (Formula 5)
0.10 ≦ (o + p) / (n + m + o + p + r + s) ≦ 0.90 (Formula 6)
0 ≦ (r + s) / (n + m + o + p + r + s) ≦ 0.10 (Formula 7)
0.1 ≦ (n + m) / (n + m + o + p + r + s) ≦ 0.9 (Formula 8) 16. The polymer electrolyte membrane according to claim 15, wherein n, m, o, p, r, and s in chemical formulas 1 to 6 satisfy the following formulas 7 to 9 and are for fuel cells using hydrogen as fuel.
0.15 ≦ (n + o + r) / (n + m + o + p + r + s) ≦ 0.70 (Equation 9)
0.01 ≦ (o + p) / (n + m + o + p + r + s) ≦ 0.70 (Formula 10)
0 ≦ (r + s) / (n + m + o + p + r + s) ≦ 0.10 (Formula 11)
0.05 ≦ (n + m) / (n + m + o + p + r + s) ≦ 0.8 (Formula 12)   A membrane / electrode assembly comprising the polymer electrolyte membrane according to claim 15 and an electrode catalyst layer.   The membrane / electrode assembly which uses the sulfonic acid group containing polymer in any one of Claims 1-14 for the electrode catalyst layer of a membrane / electrode assembly.   A fuel cell comprising the membrane / electrode assembly according to claim 18 or 19. A method for producing an aromatic nucleophilic substitution reaction of a sulfonic acid group-containing polymer according to claim 1, wherein an aliphatic group is introduced into the main chain structure, and a compound having a structure represented by Formula 11 is one of the reaction components. A method for producing a sulfonic acid group-containing polymer, wherein
[In Chemical Formula 11, R ³ represents a C 2-20 alkylene group or an aralkylene group which may contain a sulfur atom or an oxygen atom. ]