JP2012084295A - Polymer electrolyte and ionic material having polymerizable group - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a polymer electrolyte membrane having a main chain that allows a polymer electrolyte to be formed in a film with reduced thickness and excellent in hydrolysis and radical resistance; and an ionic material having a polymerizable group constituting the polymer electrolyte.SOLUTION: A polymer electrolyte includes a polymer unit represented by the chemical general formula (1). In the formula, Aand Arepresent an alkyl group, Brepresents an electron-attracting group, Brepresents an electron-donating group, Y represents a proton acid group selected from among a sulfonic acid group, a phosphonic acid group, a hydroxyl group and a carboxyl group, and n represents an integer of 10 to 10,000.

Description

  The present invention relates to a polyelectrolyte and an ionic material having a polymerizable group constituting the polyelectrolyte. Specifically, the present invention relates to a polymer electrolyte used in a fuel cell, particularly a solid polymer fuel cell.

  The polymer electrolyte fuel cell (hereinafter referred to as “PEFC”) is being researched and developed as a power source that can reduce the release of environmentally hazardous gases as a power source for fuel cell vehicles, stationary cogeneration, and mobile phones. ing. In PEFC, a power generation reaction proceeds by proton conduction in the battery. The presence of water is essential for proton conduction in the PEFC, and therefore a humidifier is required to advance the power generation reaction of the PEFC. When a fuel cell is applied to a vehicle or the like, since a humidifier is desired to be small from the viewpoint of in-vehicle performance, there is a demand for an electrolyte that performs proton conduction well even under low humidification. Fluorine resin electrolytes typified by Nafion (registered trademark, manufactured by DuPont) and Aciplex (registered trademark, manufactured by Asahi Kasei) are excellent in proton conductivity under low humidification and are widely used in PEFC It is.

  However, since the fluororesin electrolyte is a polymer material made of fluorine, it has a problem in terms of recyclability. Considering the widespread use of fuel cell vehicles, the question of whether or not it can be recycled is important, and the environmental impact of materials that cannot be recycled cannot be ignored. Furthermore, when a fluorine-based resin electrolyte is applied alone as an electrolyte membrane, there is a problem in terms of durability. Therefore, the need for an alternative material for the fluororesin electrolyte is increasing.

  As an alternative material, hydrocarbon electrolytes have been developed in recent years. Hydrocarbon materials are generally more durable than fluororesin electrolytes and are expected to replace fluororesin electrolytes.

  In order to have high proton conductivity with low humidification using a hydrocarbon electrolyte, for example, in Patent Document 1, a material having a liquid crystal skeleton is used to form a network of sulfonic acid groups, and high with low humidification. It has been reported that proton conductivity is developed.

JP 2003-55337 A

  However, the sulfonated liquid crystal polymer material obtained by increasing the molecular weight of the sulfonic acid type liquid crystal monomer material described in Patent Document 1 has a main chain of methacrylic group or an acrylic skeleton, so that it is difficult to improve the performance by thinning the film. Therefore, the decomposition reaction by hydrolysis tends to proceed.

  An object of the present invention is to solve the above-described problem, and has a main chain capable of being thinned, and is excellent in hydrolysis and radical resistance, and can be polymerized to constitute the polymer electrolyte. It is to provide an ionic material having a group.

  As a result of diligent research to achieve the above object, the present invention changes the main chain to a phenylene skeleton, improves hydrolysis resistance, removes ester sites, and improves radical resistance. We paid attention to polymer electrolyte membrane materials into which attractive groups were introduced.

  The polymer electrolyte according to claim 1 of the present invention has a polymer unit represented by the following chemical general formula (1).

In the formula, A ₁ and A ₂ are alkyl groups, B ₁ is an electron withdrawing group, B ₂ is an electron donating group, Y is selected from a sulfonic acid group, a phosphonic acid group, a hydroxyl group, and a carboxyl group. Each represents a protonic acid group. n is an integer of 10 to 10,000.

The polymer electrolyte according to claim 2 of the present invention is characterized in that in the polymer electrolyte according to claim 1, A ₁ and A ₂ are — (CH ₂ ) _m —. However, m is an integer greater than or equal to 1.

The polymer electrolyte according to claim 3 of the present invention is characterized in that in the polymer electrolyte according to claim 1 or 2, B ₁ is a carbonyl group and B ₂ is an ether group.

Polymer electrolyte according to claim 4 of the present invention is a polymer electrolyte according to claim 2 or 3, characterized in that m of A ₁ is 3 or 4.

  The polymer electrolyte according to claim 5 of the present invention is characterized in that in the polymer electrolyte according to any one of claims 1 to 4, Y is a sulfonic acid group or a phosphonic acid group. is there.

  The polymer electrolyte according to claim 6 of the present invention is the polymer electrolyte according to any one of claims 1 to 5, wherein the ion exchange capacity of the polymer electrolyte is 2.1 meq / g to 2.4 meq / g. g or less.

  A polymer electrolyte membrane according to a seventh aspect of the present invention comprises the polymer electrolyte according to any one of the first to sixth aspects.

  A solid polymer fuel cell according to an eighth aspect of the present invention is characterized by using the polymer electrolyte according to any one of the first to sixth aspects.

  The ionic material having a polymerisable group according to claim 9 of the present invention is represented by the following chemical general formula (2).

In the formula, A ₁ and A ₂ are alkyl groups, B ₁ is an electron withdrawing group, B ₂ is an electron donating group, Y is selected from a sulfonic acid group, a phosphonic acid group, a hydroxyl group, and a carboxyl group. Each represents a protonic acid group. X ₁ and X ₂ each independently represent a chlorine atom, a bromine atom, or an iodine atom.

  According to the polymer electrolyte of the present invention, by changing the main chain from an acrylic group or a methacryl skeleton to a phenylene skeleton, the polymer becomes a rigid skeleton, and the polymer electrolyte can be thinned. When the polymer electrolyte is used for a fuel cell, power generation performance can be improved. Moreover, since the polymer electrolyte of the present invention does not have an ester moiety, hydrolysis resistance can be improved. Moreover, since the polymer electrolyte of the present invention has an electron withdrawing group, radical stability can be improved.

  Hereinafter, the polymer electrolyte of the present invention will be described. Note that the present invention is not limited to the embodiments described below, and modifications such as design changes can be made based on the knowledge of those skilled in the art, and such modifications are added. The embodiments may be included in the scope of the present invention.

  The polymer electrolyte of the present invention can be obtained by polymerizing an ionic material (hereinafter sometimes referred to as “monomer”) having a polymerizable group represented by the following chemical general formula (2).

[About monomer]
In the chemical general formula (2), A ₁ and A ₂ are alkyl groups, B ₁ is an electron withdrawing group, B ₂ is an electron donating group, Y is a sulfonic acid group, a phosphonic acid group, a hydroxyl group, and a carboxyl group. Each of the protonic acid groups selected from X ₁ and X ₂ are each independently a chlorine atom, a bromine atom or an iodine atom. X ₁ and X ₂ may be the same atom or different atoms, but are preferably the same atom.
Here, the group which can be polymerized specifically refers to a group containing X ₁ or X ₂ . The ionic material means a material having a protonic acid group represented by Y.

In the chemical general formula (2), the alkyl group represented by A ₁ and A ₂ is preferably — (CH ₂ ) _m — (m is an integer of 1 or more), and m is 3 or 4 It is particularly preferred that When m is 3 or 4, a polymer electrolyte membrane having a high acid value can be obtained while maintaining the flexibility of the polymer electrolyte membrane comprising the polymer electrolyte.

In the chemical general formula (2), B ₁ is preferably an electron withdrawing group. When B ₁ is an electron withdrawing group, radical stability can be improved. Examples of the electron withdrawing group include a sulfo group, a nitro group, a cyano group, and a carbonyl group. In particular, when B ₁ is a carbonyl group, the monomer of the above general formula (2) can be easily synthesized. , Radical stability can be further improved.

In the chemical general formula (2), B ₂ is preferably an electron donating group. As the electron donating group, an ether group is particularly preferable. When B ₂ is an ether group, the monomer of the chemical general formula (2) can be easily synthesized, and the polymer electrolyte membrane made of the polymer electrolyte can be made flexible.

[Manufacturing method of monomer]
The chemical formula (2) the production method of the monomers is not particularly limited, for example, _{A 1} is - _{(CH 2)} 4 -, _{B 1} is a carbonyl group, _{B 2} is an ether group, _{A 2} is (- When CH ₂ ) ₃ — and Y are sulfonic acid groups, they can be synthesized as follows. Even if A ₁ , B ₁ , B ₂ , A ₂ , Y is not the above-described configuration, the monomer of the above general formula (2) can be obtained by combining the following synthesis method and a known synthesis method. Can be manufactured.
First, a compound (A) represented by the following chemical general formula (3) is prepared.

Here, X ₁ and X ₂ are each a chlorine atom, a bromine atom or an iodine atom. From the viewpoint of reaction efficiency, 1,4-dichlorobenzene is preferable.

  Next, the compound (C) represented by the following chemical general formula (5) can be obtained by reacting the compound (A) with the compound (B) represented by the following chemical general formula (4). .

Here, X ₁ is any one of a chlorine atom, a bromine atom and an iodine atom. From the viewpoint of reaction efficiency, a chlorine atom is preferable.

The reaction conditions at this time are not particularly limited, but the reaction temperature is preferably 25 ° C. or more and 80 ° C. or less, more preferably 40 ° C. or more and 70 ° C. or less, the reaction time is preferably 8 hours or more and 48 hours or less, More preferably, the reaction is performed for 16 hours or more and 32 hours or less.
The pressure during the reaction is not particularly limited, and may be either under pressure, under normal pressure (atmospheric pressure), or under reduced pressure, and may be appropriately set depending on circumstances, but may be under normal pressure. preferable.
The atmosphere in which the reaction is performed is not particularly limited, but it is preferably performed in an inert gas atmosphere such as argon gas or nitrogen gas.

  The compound (B) is preferably 50 mol% or more and 100 mol% or less, and more preferably 80 mol% or more and 100 mol% or less with respect to 100 mol% of the compound (A).

The catalyst used at this time may be a Lewis acid catalyst, and an example of the Lewis acid catalyst is anhydrous aluminum chloride.
The catalyst is preferably 100 mol% or more and 200 mol% or less, and more preferably 100 mol% or more and 150 mol% or less, relative to 100 mol% of the compound (A).

  Next, the compound (D) represented by the following chemical general formula (6) can be obtained by reacting the compound (C) with thionyl chloride.

The reaction conditions at this time are not particularly limited, but the reaction temperature is preferably 25 ° C. or higher and 80 ° C. or lower, more preferably 40 ° C. or higher and 60 ° C. or lower, and the reaction time is preferably 1 hour or longer and 10 ° C. The reaction is performed for a time or less, more preferably 2 hours or more and 5 hours or less.
The reaction is desirably performed in a nitrogen atmosphere from the viewpoint of reaction efficiency.
The reaction solvent used in the above reaction is preferably a good solvent. Examples thereof include tetrahydrofuran, cyclohexanone, dimethyl sulfoxide, N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, γ-butyrolactone, N, N-dimethylimidazolinone and the like.

  Next, the compound (F) represented by the following chemical formula (8) can be obtained by reacting the compound (E) represented by the following chemical formula (7) with propane sultone.

The reaction conditions at this time are not particularly limited, but the reaction temperature is preferably 25 ° C. or higher and 80 ° C. or lower. The reaction time is preferably 10 hours to 48 hours.
Moreover, there is no problem whether the atmosphere in which the reaction is performed is an air atmosphere or a nitrogen atmosphere.
The reaction solvent used at this time is preferably a good solvent, more preferably an alcohol solvent. Examples include ethanol, methanol, propanol, and 1-butanol.
The base used at this time is preferably a strong base, and examples thereof include sodium hydroxide and potassium hydroxide.

The monomer of this invention can be obtained by making the said compound (D) and the said compound (F) react. Specifically, in the chemical general formula (2), A ₁ is — (CH ₂ ) ₄ —, B ₁ is a carbonyl group, B ₂ is an ether group, and A ₂ is (—CH ₂ ) ₃ —, A monomer in which Y is a sulfonic acid group is obtained.

The reaction conditions at this time are not particularly limited, but the reaction temperature is preferably 25 ° C. or more and 80 ° C. or less, more preferably 40 ° C. or more and 70 ° C. or less, the reaction time is preferably 8 hours or more and 48 hours or less, More preferably, the reaction is performed for 16 hours or more and 32 hours or less.
The pressure during the reaction is not particularly limited, and may be either under pressure, under normal pressure (atmospheric pressure), or under reduced pressure, and may be appropriately set depending on circumstances, but may be under normal pressure. preferable.
The atmosphere in which the reaction is performed is not particularly limited, but it is preferably performed in an inert gas atmosphere such as argon gas or nitrogen gas.

  The compound (D) is preferably 50 mol% or more and 100 mol% or less, and more preferably 80 mol% or more and 100 mol% or less with respect to 100 mol% of the compound (F).

  The catalyst used at this time may be a Lewis acid catalyst, and an example of the Lewis acid catalyst is anhydrous aluminum chloride. The catalyst is preferably 100 mol% or more and 200 mol% or less, and more preferably 100 mol% or more and 150 mol% or less, relative to 100 mol% of the compound (D).

[Polymer electrolyte production method]
The polymerization of the monomer of the present invention is not particularly limited, but it is preferable to react in the presence of a specific catalyst. The catalyst used in this case is a catalyst system containing a transition metal compound. The catalyst system includes a ligand component, a transition metal complex coordinated with the ligand, and a reducing agent as essential components. A salt may be added to increase the polymerization rate.

  Examples of the ligand component include triphenylphosphine, 2,2′-bipyridine, 1,5-cyclooctadiene, 1,3-bis (diphenylphosphino) propane, and the like. Of these, triphenylphosphine and 2,2'-bipyridine are preferred. The compound which is the said ligand component may be used individually by 1 type, and may use 2 or more types together. The ligand component is preferably 1 mol% or more and 100 mol% or less, and more preferably 1 mol% or more and 20 mol% or less with respect to 100 mol% of the monomer.

  Examples of transition metal complexes in which a ligand is coordinated include nickel chloride bis (triphenylphosphine), nickel bromide bis (triphenylphosphine), nickel iodide bis (triphenylphosphine), and nickel nitrate bis (tri Phenylphosphine), nickel chloride (2,2-bipyridine), nickel bromide (2,2-bipyridine), bis (1,5-cyclooctadiene) nickel, tetrakis (triphenylphosphine) nickel, tetrakis (triphenylphos) Phyto) nickel or tetrakis (triphenylphosphine) palladium. Of these, nickel chloride bis (triphenylphosphine) and nickel chloride (2,2-bipyridine) are preferred. The transition metal complex is preferably 1 mol% or more and 100 mol% or less, and more preferably 1 mol% or more and 20 mol% or less with respect to 100 mol% of the monomer.

  Examples of the reducing agent that can be used in the catalyst system include iron, zinc, manganese, aluminum, magnesium, sodium, and calcium. Of these, zinc, magnesium and manganese are preferred. These reducing agents can be used after being more activated by bringing them into contact with an acid such as an organic acid. The reducing agent is preferably 1 mol% or more and 100 mol% or less, and preferably 10 mol% or more and 30 mol% or less with respect to 100 mol% of the monomer.

  Examples of salts that can be used in the above catalyst system include sodium compounds such as sodium fluoride, sodium chloride, sodium bromide, sodium iodide, sodium sulfate; potassium fluoride, potassium chloride, potassium bromide, iodide. Examples include potassium compounds such as potassium and potassium sulfate; ammonium compounds such as tetraethylammonium fluoride, tetraethylammonium chloride, tetraethylammonium bromide, tetraethylammonium iodide, and tetraethylammonium sulfate. Of these, sodium bromide, sodium iodide, potassium bromide, tetraethylammonium bromide, and tetraethylammonium iodide are preferred. The salt is preferably 1 mol% or more and 100 mol% or less, and preferably 10 mol% or more and 30 mol% or less with respect to 100 mol% of the monomer.

  Examples of the solvent used in the polymerization include tetrahydrofuran, cyclohexanone, dimethyl sulfoxide, N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, γ-butyrolactone, N, N-dimethylimidazolidinone and the like can be mentioned. Of these, tetrahydrofuran, N, N-dimethylformamide, N, N-dimethylacetamide, N-methyl-2-pyrrolidone, and N, N'-dimethylimidazolidinone are preferred. These polymerization solvents are preferably used after sufficiently dried.

The polymerization temperature and polymerization time during the polymerization are not particularly limited, and may be set as appropriate depending on the molecular weight, the concentration of polymerization, and the like. For example, when it is intended to obtain a polymer having a weight average molecular weight of 100,000 to 500,000, the polymerization temperature is preferably 25 ° C. or more and 80 ° C. or less, more preferably 40 ° C. or more and 70 ° C. Hereinafter, the polymerization is performed in a polymerization time of preferably 8 hours to 40 hours, more preferably 16 hours to 32 hours.
The polymerization pressure at the time of polymerization is not particularly limited, and may be any of under pressure, normal pressure (atmosphere), and reduced pressure, and may be appropriately set depending on circumstances, but is preferably under normal pressure.

  The degree of polymerization of the monomer of the present invention, that is, n in the chemical general formula (1) is preferably 10 to 10,000, and more preferably 1000 to 10,000. By being in the above range, the polymer electrolyte can be easily dissolved in the solvent, and the film forming property can be improved.

[Production method of polymer electrolyte membrane]
A method for producing a polymer electrolyte membrane using the polymer electrolyte thus obtained is not particularly limited. For example, the polyphenylene electrolyte of the present invention is dissolved in a solvent to form a solution, and then cast by casting. Examples thereof include a method of coating on a substrate and forming it into a film, a method of applying and forming a film using an applicator controlled to a predetermined gap, and a method of forming a film using a die coater.

  In film formation, the viscosity of the solution is preferably 10 mPa · s or more and 10,000 mPa · s or less, and more preferably 10 mPa · s or more and 1000 mPa · s or less. Within the above range, the residual amount of the solvent is small, the probability that a large amount of bubbles are generated when the solution is dried is low, and the unevenness of the thickness can be reduced by the leveling effect, so that stable proton conductivity is achieved. Is secured.

  The concentration of the polymer electrolyte in this case is usually 2.5% by mass or more and 50% by mass or less, preferably 7% by mass or more and 25% by mass or less, although it depends on the molecular weight. Within the above range, the film formability is excellent.

  Examples of the solvent used in this case include N-methyl-2-pyrrolidone, N, N-dimethylformamide, γ-butyllactone, N, N-dimethylacetamide, dimethyl sulfoxide, dimethylurea, dimethylimidazolidinone. And aprotic polar solvents such as methanol, ethanol, propyl alcohol, isopropyl alcohol, sec-butyl alcohol, tert-butyl alcohol and the like, and ketone solvents such as acetone, methyl ethyl ketone and cyclohexanone. These solvents may be used alone or in combination of two or more. Moreover, you may use what added water to these solvents.

  The polymer electrolyte solution whose viscosity is adjusted is cast onto a substrate, for example. Examples of the base material to be cast include metal materials, glass, ceramics, and plastics. The shape of the substrate is not particularly limited.

  The coating film formed on the substrate is preferably heated at 25 ° C. or higher and 140 ° C. or lower and 0.1 hour or longer and 24 hours or shorter to form the polymer electrolyte membrane of the present invention.

[About polymer electrolyte fuel cells]
A polymer electrolyte fuel cell generally includes a polymer electrolyte membrane, a membrane electrode assembly comprising an air electrode side electrode catalyst layer and a fuel electrode side catalyst layer provided on both sides of the polymer electrolyte membrane, and an air electrode side electrode. The air electrode side gas diffusion layer and the fuel electrode side gas diffusion layer disposed to face the catalyst layer and the fuel electrode side electrode catalyst layer, and a separator sandwiching them.

  The polymer electrolyte of the present invention has sufficient mechanical strength even when it is thinned, and can improve hydrolysis resistance and radical stability. Therefore, the polymer electrolyte membrane constituting the solid polymer fuel cell is used. It can be used as a material. Moreover, an air electrode side electrode catalyst layer or a fuel electrode side electrode catalyst layer can be formed together with the conductive material and the catalyst material.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention in detail, this invention is not limited to these.

[Example]
<Synthesis of Compound (C-1)>
Add 14.7 g (0.1 mol) of 1,4-dichlorobenzene, 13.7 g (0.1 mol) of 5-chlorovaleric acid, and 15.6 g (0.11 mol) of aluminum chloride. Stir for hours. The organic component of the reaction solution was recovered by extraction and recrystallized using cyclohexane. After drying, a compound (C-1) represented by the following chemical formula (9) was obtained.

<Synthesis of Compound (D-1)>
Under a nitrogen atmosphere, 50 g (0.2 mol) of the obtained compound (C-1), 118.9 g (1 mol) of thionyl chloride and 5 ml of dimethylformamide were added, and the mixture was heated and stirred at 45 ° C. for 4 hours to obtain the following chemical formula ( The compound (D-1) represented by 10) was obtained.

<Synthesis of Compound (F)>
Under a nitrogen atmosphere, 50 g (0.29 mol) of 4-phenylphenol (compound (E) represented by the above chemical formula (7)), 141 g (1.16 mol) of propane sultone, 20 g (0.5 mol) of sodium hydroxide, methanol Was added and stirred for 48 hours.
Then, it reprecipitated with diethyl ether and filtered. The filtrate was washed with hydrochloric acid to obtain the compound (F) represented by the above chemical formula (8).

<Synthesis of monomer>
Under a nitrogen atmosphere, 10 g (0.038 mol) of the compound (D-1), 11 g (0.038 mol) of the compound (F), 5.56 g (0.042 mol) of aluminum chloride, and 30 ml of dimethylformamide were added. The mixture was stirred at 1 ° C. for 1 hour to obtain a monomer of an example represented by the following chemical formula (11).

<Synthesis of polymer electrolyte>
Under a nitrogen atmosphere, 7.60 g (14.58 mol) of the monomer of the example, 1.493 g (5.692 mmol) of triphenylphosphine, 0.293 g (1.953 mmol) of sodium iodide, and 1.281 g (19.59 mmol) of zinc. ), 0.311 g (0.475 mmol) of bis (triphenylphosphine) nickel (II) dichloride, 20 ml of dimethylformamide as a solvent, and stirring at 60 ° C. for 24 hours, are represented by the following chemical formula (12). In this way, a polymer electrolyte of an example was obtained.

[Comparative example]
<Synthesis of 9-bromo-1-decene>
To a 500 ml Erlenmeyer flask, 100 ml of benzene and 1.0 g of pyridine were added to dissolve 25 g (0.16 mol) of 9-decene-1-ol. Next, 100 ml of a benzene solution in which 43.2 g (0.16 mol) of phosphorus tribromide was dissolved was slowly added dropwise under ice cooling, followed by stirring at room temperature for 18 hours. Thereafter, the reaction solution was poured into ice water and extracted with 300 ml of diethyl ether. The ether-benzene mixed solution obtained here was dehydrated overnight with anhydrous sodium sulfate. Sodium sulfate was removed by suction filtration, ether-benzene was removed under reduced pressure, and the residue was distilled under reduced pressure to obtain the desired product 9-bromo-1-decene.

<Synthesis of 4- (9-decenyloxyphenyl) phenol>
3.40 g (0.08 mol) of sodium hydroxide was dissolved in 100 ml of ethanol. This solution was added little by little to 100 ml ethanol in which 14.9 g (0.08 mol) of 4,4′-biphenol was dissolved, and ethanol was removed under reduced pressure. The residue was dissolved in 150 ml dimethylformamide by heating under a nitrogen stream (solution A). 15.8 g (0.072 mol) of 9-bromo-1-decene prepared above and 0.1 g of phenothiazine were dissolved in 30 ml of DMF (liquid B). Liquid B was added to liquid A over about 30 minutes while stirring well in a nitrogen atmosphere, and reacted at 40 ° C. for 24 hours. After completion of the reaction, the reaction solution was cooled, washed with 300 ml of 10% cold hydrochloric acid, extracted with 300 ml of ether, and then washed with 100 ml of cold distilled water. The ether layer is dehydrated with anhydrous sodium sulfate overnight. 300 ml of hexane is added to the residue, and a precipitate is obtained by filtration. Subsequently, 200 ml of benzene was added, and the benzene-soluble part was purified by column chromatography using benzene to obtain 4- (9-decenyloxyphenyl) phenol.

<Synthesis of 3- [6- (9-decenyloxy) biphenyloxy] propylsulfonic acid>
In 30 ml of dimethylformamide, 0.05 g of a polymerization inhibitor phenothiazine was dissolved. There, 1,8-diazabicyclo [5,4,0] -7-undencene (DBU) 1.22 g (0.008 mol) and 4- (9-decenyloxyphenyl) phenol 0.65 g (0.002 mol) ), 1.8 g (0.008 mol) of sodium 3-bromopropanesulfonate was dissolved and stirred at 50 ° C. for 48 hours under a nitrogen atmosphere. After completion of the reaction, the solvent was concentrated, diethyl ether was added and filtered to obtain a precipitate. Next, the precipitate was washed well with distilled water. Next, after the washed precipitate was stirred in 6 mol / L HCl for 24 hours, the precipitate was obtained by a centrifuge, and this precipitate was washed with diethyl ether and dried to obtain a monomer of Comparative Example 3- [6- (9-decenyloxy) biphenyloxy] propylsulfonic acid was obtained.

<Molecularization of 3- [6- (9-decenyloxy) biphenyloxy] propylsulfonic acid>
Under a nitrogen atmosphere, 488 mg (1 mmol) of 3- [6- (9-decenyloxy) biphenyloxy] propylsulfonic acid, 6.6 mg (0.04 mmol) of AIBN as an initiator, and 4.8 ml of dimethyl sulfoxide were added. It was. Then, it polymerized by heat polymerization at 60 ° C. for 60 hours. Then, it reprecipitated with acetone and obtained 3- [6- (9-decenyloxy) biphenyloxy] propylsulfonic acid polymer which is a polymer electrolyte of a comparative example.

[Polymer electrolyte deposition]
The polymer electrolytes of Examples and Comparative Examples were dissolved in dimethyl sulfoxide, cast into glass, and vacuum-dried at 45 ° C. for 12 hours, 80 ° C. for 12 hours, and 80 ° C. for 1 hour. A polymer electrolyte membrane was obtained.

[Evaluation]
<Thinning>
The polymer electrolyte membrane of the example had a mechanical strength that can produce a membrane electrode assembly even if it was made thinner than the polymer electrolyte membrane of the comparative example.

<Fenton test>
The polymer electrolyte membranes of Examples and Comparative Examples were immersed in 60 ° C., 3% hydrogen peroxide aqueous solution, and 4 ppm Fe ²⁺ . As a result, it was confirmed that the polymer electrolyte membrane of the example had durability.

  The present invention relates to a polymer constituting a polymer electrolyte fuel cell used as a power generation source for automobiles such as electric vehicles and fuel cell vehicles, mobile devices such as notebook computers, mobile phones and personal digital assistants, and household power generators. It can be used for electrolyte membranes.

Claims (9)

A polymer electrolyte comprising a polymer unit represented by the following chemical general formula (1):

In the formula, A ₁ and A ₂ are alkyl groups, B ₁ is an electron withdrawing group, B ₂ is an electron donating group, Y is selected from a sulfonic acid group, a phosphonic acid group, a hydroxyl group, and a carboxyl group. Each represents a protonic acid group. n is an integer of 10 to 10,000. The polymer electrolyte according to claim 1, wherein the A ₁ and A ₂ are — (CH ₂ ) _m —. However, m is an integer greater than or equal to 1. 3. The polymer electrolyte according to claim _1, wherein B ₁ is a carbonyl group, and B ₂ is an ether group. 4. The polymer electrolyte according to claim 2, wherein m of A ₁ is 3 or 4. 5.   The polymer electrolyte according to any one of claims 1 to 4, wherein Y is a sulfonic acid group or a phosphonic acid group.   6. The polymer electrolyte according to claim 1, wherein an ion exchange capacity of the polymer electrolyte is 2.1 meq / g or more and 2.4 meq / g or less.   A polymer electrolyte membrane comprising the polymer electrolyte according to any one of claims 1 to 6.   A polymer electrolyte according to any one of claims 1 to 6, wherein the polymer electrolyte fuel cell is used. An ionic material having a group capable of being polymerized, which is represented by the following chemical general formula (2).

In the formula, A ₁ and A ₂ are alkyl groups, B ₁ is an electron withdrawing group, B ₂ is an electron donating group, Y is selected from a sulfonic acid group, a phosphonic acid group, a hydroxyl group, and a carboxyl group. Each represents a protonic acid group. X ₁ and X ₂ each independently represent a chlorine atom, a bromine atom, or an iodine atom.