KR101371796B1 - Electrloyte membrane including poly(tetra phenyl ether sulfone) containing pendant quaternary ammonium hydroxide group and alkaline fuel cell comprising the same - Google Patents

Abstract

The present invention relates to a poly (tetraphenyl ether) sulfone copolymer in which a plurality of quaternary ammonium hydroxide groups are introduced into a repeating unit, a method for preparing the same, and a polymer electrolyte membrane for an alkaline fuel cell including the copolymer.
In the present invention, by introducing two to six ammonium hydroxide groups in the aromatic ring located in the side chain of the copolymer, not only exhibits high ionic conductivity and thermal stability, but also increases the conductivity of hydroxyl ions due to the clustering effect between hydrophilic moieties due to structural specificity. Can be.

Description

TETRA PHENYL ETHER SULFONE CONTAINING PENDANT QUATERNARY AMMONIUM HYDROXIDE GROUP AND ALKALINE FUEL CELL COMPRISING THE SAME}

New to improve ion conductivity ^of-the present invention a plurality of quaternary hydroxide, ammonium groups are due to the structural specificity is introduced, because of the high ionic conductivity, the clustering effect between as well as the hydrophilic moiety thermal stability hydroxyl group (OH) in the repeating unit Poly (tetraphenyl ether) sulfone copolymer, a method for producing the same, and the use of the copolymer.

Fuel cells are one of the most efficient and clean sources of energy to replace fossil fuels. Among these, alkaline polymer electrolyte fuel cells (ALPFCs) provide many advantages such as high efficiency, high energy density, soundproof operation and environmental friendliness. The alkaline electrolyte fuel cell uses anion-exchange membranes (AEMs) as polymer electrolyte membranes. However, currently commercial APEFCs with crosslinked polystyrene backbones are typically not stable in high pH environments. Therefore, there is interest in developing a new anion exchange membrane that is stable in high pH and high temperature environments and maintains high ion conductivity and ion selectivity. Currently, perfluorinated polyelectrolyte membranes such as Nafion® and Flemion® are widely used as materials for polymer electrolyte membranes due to their excellent chemical stability, physical stability and high proton conductivity. However, these have not only problems such as limited operating temperature (0 to 80 ° C.), high cost, insufficient durability, and high methanol permeability, but also dependence of platinum catalyst, making it difficult to solve the problem of high cost.

On the other hand, alkaline fuel cells have numerous advantages over proton exchange membrane fuel cells in terms of reaction rate and ohmic polarization of the anode. For example, in an alkaline fuel cell, since the atmosphere of the positive electrode is basic, the voltage can be improved by selecting an inert cathode catalyst for the fuel that has permeated the membrane, and catalysts other than expensive precious metals can also be used. The selection range becomes wider. In addition, the alkaline fuel cell is designed to move and transfer hydroxyl ions (OH ⁻ ) into the electrolyte membrane during the electrochemical reaction, thereby using an anion exchange electrolyte membrane. Therefore, the study of anion exchange electrolyte membrane having high ion exchange capacity and high conductivity is important, and it is also important to develop a major relationship between the structure and the physical properties of these ion conductive electrolyte membrane types. As an alternative proton exchange electrolyte membrane, ammonium hydroxide aromatic polymers have been synthesized, but until now it has been difficult to achieve an ideal balance between high ionic conductivity and low water uptake. In addition, the ammonium cation density of the ammonium cation makes the electrolyte membrane more swellable in water, thereby lowering the performance of the fuel cell. Therefore, there is an urgent need to study anion exchange electrolyte membrane having low solubility in water, high ion exchange capacity and high conductivity.

The present invention has been made to solve the above-mentioned problems, recognizing that the chemical structure of the monomer constituting the polymer copolymer is very important, so that the ammonium ion is substituted in the side chain of the polymer, hydrophilic and hydrophobic polymer chain The new chemical structure of the monomer that can improve the ionic conductivity is well developed by the phase separation from each other.

Accordingly, an object of the present invention is to provide a novel poly (tetraphenylether) sulfone copolymer which can be used as a polymer hydroxide exchange membrane material by introducing a plurality of quaternary ammonium groups into a repeating unit of a polymer, and a method for preparing the same. .

Another object of the present invention is to provide a polymer electrolyte membrane including the novel poly (tetraphenyl ether) sulfone copolymer having low solubility in water, low water absorption, and high conductivity, and an alkaline fuel cell having the same. It is done.

The present invention provides a poly (tetraphenyl ether) sulfone copolymer including a quaternary ammonium hydroxide base in a repeating unit represented by the following Formula 1.

Where

또는

이고,Ar ₁ is

or

ego,

E is a single bond, O, S, C (= O), S (= O), S (= O) 2, C (CH 3) 2, C (CF 3) 2, Si (CH 3) 2, P and (= O) CH ₃ or C (= O) NH,

Z ₁ and Z ₂ are the same or different from each other and each independently represents hydrogen or a C ₁ -C ₆ alkyl group, and the C ₁ -C ₆ alkyl group may be substituted with a halogen, a cyano group, or a sulfone group,

R is an alkyl group of C ₁ ~ C _6,

R ₁ to R ₄ are the same as or different from each other, and each independently hydrogen or an aromatic group, two or more of them are aromatic groups, and R ₁ to R ₄ are substituted with two or more ammonium groups,

x is 0.01 to 1,

m is 0.1 to 0.9, and n is 0.9 to 0.1.

In another aspect, the present invention provides a polymer electrolyte membrane (membrane) comprising the above-described poly (tetraphenyl ether) sulfone copolymer. In this case, the electrolyte membrane is preferably an anion exchange electrolyte membrane that conducts hydroxyl (OH ⁻ ) ions.

In addition, the present invention provides a membrane electrode assembly (MEA) including the polymer electrolyte membrane, and a fuel cell including the same. In this case, the fuel cell is preferably an alkaline fuel cell (AFC).

Furthermore, the present invention provides a method for producing a poly (tetraphenyl ether) sulfone copolymer represented by the formula (1).

According to a preferred embodiment of the present invention, as shown in the following Reaction Scheme 1, the process comprises: (i) polymerizing a polyphenyl monomer represented by the formula (3), a dihydroxy monomer represented by the formula (4) and a dihalide monomer represented by the formula Synthesizing a polymer represented by Formula (6); (Ii) synthesizing the polymer of Formula 7 by introducing a chloromethyl group into the polymer of Formula 6; And (iii) a quarternization reaction of the polymer of Formula 7 and treatment with an alkaline solution.

[Reaction Scheme 1]

In Scheme 1, X is F, Cl, Br, or I,

R ₅ to R ₈ are the same or different from each other and each independently represents hydrogen or an aromatic group, at least two of them are aromatic groups,

R ₉ to R ₁₂ are the same as or different from each other, and each independently hydrogen or an aromatic group, at least two of which are aromatic groups, and R ₉ to R ₁₂ are substituted with two or more chloromethyl groups,

Y is a chloromethyl group (CH ₂ Cl),

Ar ₁ , R ₁ to R ₄ , R, x, m, n are as defined in the formula (1).

The polymer electrolyte membrane comprising the novel poly (tetraphenylether) sulfone copolymer of the present invention exhibits low solubility, low water absorption, high conductivity and thermal stability in water, as well as a plurality of introduced into the aromatic ring located in the copolymer side chain. Due to the quaternary ammonium hydroxide bases, the clustering effect between the hydrophilic moieties can exert high hydroxyl ion and conductivity.

Therefore, it can be usefully used in the field of anion exchange electrolyte membrane in which hydroxyl ions are conducted and in fuel cells employing the same.

1 is a graph showing the ¹ H NMR results of PTPES (a) prepared in Synthesis Example 2, CH ₂ Cl-PTPES (b) prepared in Synthesis Example 3, PTPES-QAH (c) prepared in Example 1 .
Figure 2 is a graph showing the FT-IR results of PTPES (a) prepared in Synthesis Example 2, CH ₂ Cl-PTPES (b) prepared in Synthesis Example 3, PTPES-QAH (c) prepared in Example 1 .
3 is a graph showing the results of TGA analysis of PTPES, CH ₂ Cl-PTPES, and PTPES-QAH under atmospheric conditions.
4 is a graph showing the results of TGA analysis of PTPES-QAHs under atmospheric conditions.
5 is a graph showing the results of ion exchange capacity (IEC) and water absorption (30 ° C.) of PTPES-QAHs.
6 is a graph showing the ionic conductivity of PTPES-QAH at 40 ° C., 60 ° C., 80 ° C. under 100% RH (humidity).

Hereinafter, the present invention will be described in detail.

The present invention not only retains all the physical properties required in an alkaline fuel cell, but also provides a polymer electrolyte membrane having high hydroxyl ion (eg, OH ⁻ ) conductivity.

To this end, in the present invention, a poly (tetraphenylether) sulfone copolymer (PTPES) containing a multiphenyl group in the polymer backbone is synthesized, and a multi-phenyl pendant unit of such a copolymer exists. At least two quaternary ammonium hydroxide bases, preferably at least four, up to six quaternary ammonium hydroxide groups are introduced into the side chain.

Here, the quaternary ammonium hydroxide base group located in the side chain of the copolymer of the present application is a strong basic group having excellent anion conductivity. In the present invention, since the aforementioned quaternary ammonium hydroxide base contains two or more, preferably about 4 to 6, the hydroxyl group (OH ^{−-) is} superior due to the clustering effect and hydrophilic / hydrophobic separation between the hydrophilic moieties. ) Can exhibit ionic conductivity. Therefore, the efficiency of the anion exchange electrolyte membrane and the performance of the fuel cell having the same can be improved.

In addition, due to the rigid structure of the polymer electrolyte membrane, it may exhibit low solubility in water, low water absorption, high conductivity characteristics, and thermal stability.

<Poly (tetraphenyl ether) sulfone copolymer>

More specifically, the poly (tetraphenyl ether) sulfone copolymer of the present invention may be represented by the following formula (1).

[Chemical Formula 1]

Where

또는

이고,Ar ₁ is

or

ego,

E is a single bond, O, S, C (= O), S (= O), S (= O) 2, C (CH 3) 2, C (CF 3) 2, Si (CH 3) 2, P and (= O) CH ₃ or C (= O) NH,

Z ₁ and Z ₂ are the same or different from each other and each independently represents hydrogen or a C ₁ -C ₆ alkyl group, and the C ₁ -C ₆ alkyl group may be substituted with a halogen, a cyano group, or a sulfone group,

R is an alkyl group of C ₁ ~ C _6,

R ₁ to R ₄ are the same as or different from each other, and each independently hydrogen or an aromatic group, at least two of them are aromatic groups, wherein at least two aromatic groups are substituted with two or more quaternary ammonium groups,

x is 0.01 to 1,

m is 0.1 to 0.9, and n is 0.9 to 0.1.

Here, the aromatic group is C ₁ ~ C a substituted or unsubstituted with an alkyl group of _{6-substituted} phenyl group, C ₁ ~ C substituted with an alkyl group of ₆ or unsubstituted aryl group, C ₁ ~ substituted or unsubstituted heteroaryl with an alkyl group of C ₆ An aryl group or a naphthyl group unsubstituted or substituted with a C ₁ to C ₆ alkyl group is possible, and preferably may be a phenyl group.

In Formula 1, R ₁ to R ₄ are anion exchange groups, and all four are aromatic groups, and these four aromatic groups are preferably substituted with four or more quaternary ammonium groups. In particular, it is more preferable that R ₁ to R ₄ are each independently a phenyl group substituted with four or more quaternary ammonium hydroxide groups.

Most preferably, E is _{S (= O 2), Z} 1 and Z ₂ is a hydrogen atom, R is CH ₂ N (CH _{3) 3,} and, R ₁ to R ₄ is 4 to 8 quaternary hydroxide A phenyl group substituted with an ammonium group, x is 0.5, m is 0.5 and n is 0.5.

In addition, the poly (tetraphenyl ether) sulfone copolymer in which the quaternary ammonium base is introduced may be introduced into the side chain of 4 to 6, thereby controlling the molar ratio of the monomer without excessively using the monomer for introducing the quaternary ammonium base. Can be achieved.

The poly (tetraphenylether) sulfone copolymer according to the present invention may be a random or block copolymer.

The poly (tetraphenyl ether) sulfone copolymer is designed to have an appropriate molecular weight in the manufacturing step, preferably the weight average molecular weight (Mw) may be in the range of 10,000 ~ 1,000,000. If the amount is less than the above range, the mechanical properties and the chemical stability are insufficient. On the other hand, if the amount is in excess of the above range, the viscosity becomes too high, which makes handling difficult.

The compound of formula (1) according to the present invention may be further represented by the following formula (2). However, it is not limited to the following formulas.

Where

m is 0.1 to 0.9, and n is 0.9 to 0.1.

<Method for producing poly (tetraphenyl ether) sulfone copolymer>

Poly (tetraphenyl ether) sulfone copolymer (PTPES) according to the present invention, as shown in Scheme 1, after the polycondensation polymerization of PTPES containing a multi-phenyl group in the polymer backbone, and the chloromethylating agent Tetra-chloromethylated PTPES can be prepared by carrying out a chloromethylation reaction using a Lewis acid catalyst, and prepared by quaternization reaction and alkaline solution treatment. However, the present invention is not limited thereto, and the steps of each process may be modified or selectively mixed if necessary.

In one preferred embodiment of the above-described production method, there is provided a process for preparing a polymer represented by the formula (6) by polymerizing (i) a polyphenyl monomer represented by the formula (3), a dihydroxy monomer represented by the formula (4) and a dihalide monomer represented by the formula ; (Ii) synthesizing the polymer of Formula 7 by introducing a chloromethyl group into the polymer of Formula 6; And (iii) quaternary ammonization of the polymer of Formula 7 and treatment with alkaline solution.

Referring to Scheme 1, the poly (tetraphenyl ether) sulfone copolymer manufacturing method of the present invention will be described in more detail by dividing each step as follows.

(i) preparing poly (tetra phenyl ether sulfone) s, PTPES]

As shown in Reaction Scheme 1, this step can be carried out by mixing the polyphenyl monomers represented by the formula (3), the dihydroxy monomers represented by the formula (4) and the dihalide monomers represented by the formula (5) in consideration of the stoichiometric ratio, To synthesize the polymer represented by the formula (6).

The condensation polymerization proceeds through a nucleophilic substitution reaction through an activation step and a polymerization step. Such a reaction can be carried out under reaction conditions generally known in the art to which the present invention belongs, and therefore, the present invention is not particularly limited thereto.

The polyphenyl monomer of Formula 3 is not particularly limited as long as it is a compound having a structure including a polyphenyl group, but 1,2-bis (4-hydroxybenzene) -3,4,5,6-tetraphenylbenzene (BHPTPB) .

The synthesis of 1,2-bis (4-hydroxybenzene) -3,4,5,6-tetraphenylbenzene (BHPTPB) can be carried out as shown in Scheme 2 below.

For example, bromination of 1,2-bis (4-methoxybenzene) -ethylene synthesized by a McMurry coupling reaction produces 1,2-bis (4-methoxybenzene) -1, After 2-dibromoethylene is obtained, a high yield of 1,2-bis (4-methoxybenzene) -acetylene can be obtained by treatment with acetone in the presence of triethylamine. (4-methoxybenzene) -acetylene and tetraphenylcyclopentadienone in a sulfolane at a reflux temperature, followed by a Diels-Alder reaction with 1,2-bis (4-methoxybenzene) Benzene) -3,4,5,6-tetraphenylbenzene (yield: 95%), which was then subjected to a hydroxylation reaction with BBr ₃ in dichloromethane at room temperature to give 1,2- Roxybenzene) -3,4,5,6-tetra-phenylbenzene. However, it is not limited to the above-mentioned production method, but may be produced by other manufacturing methods known in the art.

The dihydroxy monomers of formula (4) are preferably exemplified by the following compounds, but are not limited thereto.

The dihalide monomer of Formula 5 is preferably, but not limited to, the following compounds.

The dihydroxy monomer of formula (4) and the dihalide monomer of formula (5) may react with 0 to 1 mole and 1 to 2 mole, respectively, per mole of the polyphenyl monomer of formula (3).

The polymerization reaction is carried out in an organic solvent and is not particularly limited in the present invention as long as it can dissolve reactants and products well. For example, toluene, dimethylacetamide, N-methylpyrrolidone, dimethylsulfoxide, xylene, benzene, n-butyl acetate, methylcyclohexane, dimethylcyclohexane and mixed solvents thereof are possible.

At this time, the reaction may proceed under an alkali metal base to facilitate the condensation polymerization reaction. The alkali metal base is preferably potassium carbonate, sodium carbonate, sodium hydroxide, or calcium hydroxide.

(Ii) chloromethylation reaction step

The reason for the chloromethylation of the polymer in this step is that quaternary ammoniumation with monoamines or diamines does not occur directly in the polymer backbone, but the chloromethyl groups react with monoamines and diamines to produce quaternary ammonium groups that can transport anions. To do that. When the chloromethylation reaction is carried out, tetra-chloromethylated PTPES copolymer is formed. Tetraphenyl rings located in the side chain of PTPES are selectively chloromethylated, while adjacent to sulfone groups in the main chain. The phenyl groups are inactivated in the chloromethylation reaction by a strong electron-withdrawing group.

In this step, a Friedel-Crafts chloromethylation reaction is performed by adding a chloromethylating agent to the polymer solution containing the PTPES polymer obtained in the previous step. At this time, it is preferable to further add a Lewis acid catalyst in addition to the chloromethylating agent.

The solvent may dissolve the polymer synthesized in the present invention, and may be used that does not inhibit the chloromethylation reaction of the polymer. Non-limiting examples of solvents that can be used include 1,1,2,2-tetrachloroethane (TCE), 1,2-dichloroethane (DCE), or mixtures thereof.

In the aforementioned chloromethylation reaction, it is preferable to react the PTPES compound with the chloromethylating agent in the presence of a Lewis acid catalyst.

Non-limiting examples of chloromethylating agents that can be used include chloromethylmethyl ether, chloromethyl ether, chloromethyl octyl ether or mixtures of one or more thereof.

In addition, the Lewis acid catalyst may be one or more selected from the group consisting of ZnCl ₂ and SOCl ₂ , and it is preferable to use both of them in consideration of the reaction rate and the yield of the chloromethylation reaction.

The Friedel-Craft chloromethylation reaction of the polymers depends on various variables such as the concentration of the polymer, chloromethylmethyl ether, type and content of Lewis acid catalyst, reaction time and temperature. The present invention has recognized that the reaction temperature, the rate of use of the chloromethylating agent and the amount of Lewis acid catalyst for PTPES are important. Accordingly, in the present invention, the molar ratio of ZnCl ₂ : SOCl ₂ is preferably in the range of 1: 3.6 to 4.0, more preferably 1: 3.6. In addition, the molar ratio of the chloromethylating agent: compound of formula 6 is preferably in the range of 38 to 42: 1, more preferably 40: 1.

Moreover, it is preferable that reaction temperature is 30-90 degreeC range. If the reaction temperature is less than 30 ℃ does not occur the reaction, if it exceeds 90 ℃ self crosslinking of the polymer occurs and the reaction becomes impossible. In addition, the chloromethylation reaction time is preferably 1 to 6 hours. Chloromethylation reaction occurs in less than 1 hour and self-crosslinking of the polymer becomes remarkable when it exceeds 6 hours.

On the other hand, when the chloromethylation reaction is completed, chloromethylated PTPES (CH ₂ Cl-PTPES) is immersed in an alcohol solvent having 1 to 10 carbon atoms, washed one or more times, and then dried under vacuum to give chloromethylated-PTPES (CH ₂ Cl-PTPES) can be obtained. As an example of the alcohol solvent having 1 to 10 carbon atoms, methanol may be used.

The chloromethylated PTPES copolymer prepared through the chloromethylation reaction described above may be represented by Chemical Formula 7 shown in Scheme 1.

In Formula 7, R ₉ to R ₁₂ are the same as or different from each other, and each independently hydrogen or an aromatic group, at least two of them are aromatic groups, and at least two aromatic groups are substituted with two or more chloromethyl groups. . Preferably all four are aromatic groups, and these four aromatic groups (eg, phenyl groups) are substituted with four or more chloromethyl groups.

(Iii) quaternary ammoniumation reaction step

In this step, the chloromethylated PTPES copolymer is dissolved in a solvent in the previous step and then amine is added to carry out the amination reaction.

The reason for the amination reaction in the chloromethylated PTPES copolymer in this step is to produce a quaternary ammonium group capable of reacting the chloromethyl group of the polymer and monoamine or diamine to move anion.

In the previous step, the chloromethylated PTPES copolymer was added to any one solvent selected from dimethylacetamide (DMAc), dimethylformamide (DMF), dimethylsulfoxide (DMSO) and N-methylpyrrolidone (NMP). The methylated polymer is dissolved to a concentration of 1 to 40 wt%.

In the amination reaction of the chloromethylated PTPES copolymer, the amination reaction may be performed by adding diamine, tertiary monoamine or a mixture of diamine and tertiary monoamine to a solution in which chloromethylated polymer is dissolved.

Non-limiting examples of diamines that can be used include tetramethylmethanediamine (N, N, N ', N'-tetramethyl metanediamine), tetramethylethylenediamine (N, N, N', N'-tetramethylethylenediamine), tetramethyl- 1,3-propanediamine (N, N, N ', N'-tetramethyl-1,3-propanediamine), tetramethyl-1,4-butanediamine (N, N, N', N'-tetramethyl-1, 4-butanediamine), tetramethyl-1,6-hexanediamine (N, N, N ', N'-tetramethyl-1,6-hexanediamine) or mixtures of one or more thereof.

Non-limiting examples of tertiary monoamines that may be used also include trimethylamine (TMA), triethylamine (TEA), diethylphenylamine, or mixtures of one or more thereof.

As a preferable example of the amination reaction of step (iii), diamine, tertiary monoamine or mixture of diamine and tertiary monoamine with respect to 1 mole of chloromethylated polymer in a solution in which chloromethylated PTPES copolymer is dissolved 1 An amination reaction may be performed by adding ˜4 mol and stirring or immersing at 35 ° C. to 90 ° C. for 1 to 100 hours.

(iv) alkaline solution treatment step

After this step, the quaternary ammonium-forming reaction of PTPES copolymer (PTPES-QAC) was washed with distilled water and treated with an alkali solution ^Cl-dried after ion exchange ^with-an anion OH.

The reason for the treatment with the alkaline solution in this step is to replace the end group of the quaternary ammonium group in the aminated polymer with hydroxyl ions to improve the hydroxide ion conductivity in the future.

As a non-limiting example of the alkaline solution that can be used, any one selected from potassium hydroxide (KOH), sodium hydroxide (NaOH), and lithium hydroxide (LiOH) can be used. At this time, the amount of the alkali solution is not particularly limited, but may be, for example, in the range of 5000 to 10000 parts by weight of 0.1 to 1 molar alkali solution based on 100 parts by weight of the polymer.

As a preferred example of the above step, the quaternary ammonium-reacted PTPES copolymer (PTPES-QAC) in the previous step is immersed in distilled water, washed one or more times several times and then dried under vacuum, and then in an alkaline solution 20 to 70 After immersion treatment at 0.1 ℃ for 200 hours and dried to obtain the PTPES-QAH represented by the formula (1).

If necessary, the above-described PTPES-QAC may be deposited on a glass substrate according to a conventional method known in the art, and then immersed in an alkaline solution. At this time, in order for the quaternary ammonium base to be introduced into the membrane, the thickness of the formed membrane is preferably adjusted to 50 μm or less.

Polymer electrolyte membrane

The present invention includes a polymer electrolyte membrane comprising a poly (tetraphenylether) sulfone copolymer (PEPES-QAH) containing a quaternary ammonium hydroxide base prepared by the method described above. Wherein said polymer electrolyte membrane hydroxyl (OH ^{-) -} to move the ions, and wherein the anion exchange membrane electrolyte that can pass and serves to selectively transmit ions, OH bring an alkali aqueous solution or -OH.

The polymer electrolyte membrane may be prepared by a conventional method known in the art, except for using the poly (tetraphenylether) sulfone copolymer (PTPES-QAH) including the quaternary ammonium hydroxide base according to the present invention. Can be.

As an example of a preferred method for producing a polymer electrolyte membrane according to the present invention, the poly (tetraphenylether) sulfone copolymer (PTPES-QAH) may be selected from dimethylacrylic acid (DMAc) and N-methyl-2-pyrrolidone (NMP). After dissolving in an organic solvent, such as dimethylformamide (DMF), it can be produced by casting on a glass plate and dried for 12 to 36 hours at 80 ~ 160 ℃.

At this time, in the present invention, in addition to the poly (tetraphenyl ether) sulfone copolymer (PTPES-QAH) described above, conventional components that can be used in the preparation of a polymer electrolyte membrane in the technical field to which the present invention pertains, for example, polymers, inorganic materials or other additives, etc. Can be further added.

Non-limiting examples of polymers that can be used include polysulfones, polyetherketones, polyetheretherketones, polybenzimidazole-based polymers, or mixtures of one or more thereof.

Further non-limiting examples of inorganic materials usable are silica (SiO _2), titania (TiO _2), an inorganic acid, sulfonic silica, sulfonated zirconium oxide sulfonate (ZrO), sulfonated zirconium phosphate (ZrP), or they And may be in the form of a mixture of one or more species.

In the present invention, the polymer electrolyte membrane may further include a porous support, and these components may be used without limitation in a conventional polymer component known in the art. For example, a resin woven fabric, a nonwoven fabric, a porous film, or the like can be used. More specific examples thereof include polyolefin resins such as polyethylene, polypropylene, and polymethylpentene, polytetrafluoroethylene, poly (tetrafluoroethylene-hexafluoropropylene ), A fluorine resin such as polyvinylidene fluoride, or the like can be used. If necessary, the polymer electrolyte membrane may further include an anion exchange group known in the art, for example, 1 to 3 amino groups, pyridyl groups, imidazole groups, quaternary pyridinium bases, and quaternary imidazolium bases.

The thickness of the polymer electrolyte membrane is usually in the range of 5 to 200 mu m, more preferably in the range of 10 to 50 mu m, from the viewpoint that the electrical resistance can be suppressed to a low level at this time and the mechanical strength required as the support film is given.

The polymer electrolyte membrane according to the present invention showed a high ion exchange capacity (IEC) in the range of 1.31 to 2.00 meq./g, a water content (WU) range of 25.3-87.82% at room temperature, and high thermal stability. Proton conductivity was similar to that of conventional hydrocarbon electrolyte membranes. This shows that the proton conductivity and the electrolyte membrane impregnation are significantly dependent on the chemical structure of the monomer and the polymer matrix. In the present invention, the polymer electrolyte membrane containing the multi-phenyl pendant unit is used as an excellent anion conductivity. The possibility is verified.

Meanwhile, the present invention mainly describes the use of the above-described polymer electrolyte membrane as an anionic polymer electrolyte membrane of an alkaline fuel cell, but can be used without limitation to conventional anion exchange resins and anion exchange membranes known in the art.

Membrane Electrode Assembly (MEA)

The present invention is disposed between an anode (anode), a cathode (cathode), and a positive electrode, the membrane electrode assembly (Membrane-) comprising a polymer electrolyte membrane containing the above-described PTPES-QAH Electrode Assembly).

The membrane electrode assembly includes a polymer electrolyte membrane and a pair of electrodes disposed on both sides of the polymer electrolyte membrane. The both electrodes each include an electrode substrate and a catalyst layer formed on the surface of the electrode substrate.

The cathode electrode receives a oxidant transferred from the electrode substrate to the cathode catalyst layer and electrons transferred from the anode electrode to cause a reduction reaction to generate hydroxyl (OH ⁻ ) ions. The anode electrode is a fuel and anionic polymer delivered through the electrode substrate. the electric energy generated by the ions and the oxidation reaction in a process for emitting an ^{electron-hydroxyl} (OH) which is passed through an electrolyte membrane.

The catalyst layer can generally be an electrode or a metal catalyst which can be used as an anode catalyst or a cathode catalyst in a fuel cell. For example, the anode electrode may be formed of a material selected from the group consisting of Ag, silver alloy, platinum, ruthenium, osmium, platinum-ruthenium alloy, platinum-osmium alloy, platinum-palladium alloy or platinum- , At least one transition metal selected from Mn, Fe, Co, Ni, Cu and Zn).

In addition, since an anion exchange membrane is used, it is possible to use various metal oxides which could not be used in conventional strongly acidic cation exchange membranes as electrode catalysts. For example, a perovskite oxide represented by ABO ₃ having excellent oxidation activity and the like can also be preferably used. For example, a partial substitution of LaMnO ₃ , LaFeO ₃ , LaCrO ₃ , LaCoO ₃ , LaNiO _3, etc. or a part of the A position with Sr, Ca, Ba, Ce, Ag, etc., and a part of the B position is Pd, Perovskite oxides partially substituted with Pt, Ru, Ag or the like can also be preferably used as the electrolytic catalyst. In this case, the above-described metal catalysts may be used in a form supported on a conventional carrier known in the art.

The electrode substrate plays a role of supporting the electrode for the fuel cell and diffusion of the reaction gas into the catalyst layer so that the reaction gas can be easily accessed to the catalyst layer and the function of conducting electrons generated in the reaction do. Non-limiting examples of the electrode substrate include carbon paper, carbon cloth, carbon felt, or metal cloth. In addition, the use of the carbon fiber paper or the carbon cloth which is subjected to water repellency treatment with a fluorine-based resin can prevent the gas diffusion efficiency from being lowered by the water generated when the fuel cell is driven.

In addition, the anode and the cathode may further include a microporous layer for further enhancing the gas diffusion effect between the electrode substrate and the catalyst layer. The microporous layer is formed by applying a conductive powder material, a binder and, if necessary, an ion conductive material.

<Alkali fuel cell>

The present invention provides a fuel cell, preferably an alkaline fuel cell, comprising the membrane electrode assembly described above.

Here, the fuel cell may have a conventional configuration known in the art, and may include at least one electricity generating unit that generates electricity through an electrochemical reaction between a fuel and an oxidant. A fuel supply unit for supplying the fuel to the electricity generation unit; An oxidant supply unit for supplying the oxidant to the electricity generating unit, and a separator.

In addition, there are no limitations on the various materials used for the alkaline fuel cell, the manufacturing method of the assembly or the fuel cell, and the materials and manufacturing methods conventionally employed in the alkaline fuel cell can be used without particular limitation.

Hereinafter, the present invention will be described in more detail with reference to the following examples. It should be understood that these examples are for the purpose of illustrating the present invention more specifically, and the scope of the present invention is not limited to these examples. It will be apparent to those skilled in the art that the present invention is not limited thereto.

<Material>

Chemicals used in the synthesis examples and examples of the present invention, for example zinc powder, TiCl ₄ , pyridine, 4-methoxybenzaldehyde, bromine, triethylamine (TEA), potassium carbonate, tetraphenyl cyclophenyldienone, 4 , 4'-difluorophenylsulfone, zinc chloride, boron tribromide, bis (4-hydroxyphenylylsulfone), thionyl chloride, potassium hydroxide, 30% trimethyl Amine solution (TMA), 1,1'2,2'-tetrachloroethane, sodium sulfate, phenolphthalein, chloromethylmethylether, sodium chloride, sulfolane, potassium hydroxide, sodium hydroxide, hydrochloric acid, and concentrated sulfuric acid It was purchased from Chemical Company (Aldrich Chemical).

Commercial grade NMP and toluene were dried under calcium hydride and distilled before use.

In addition, other commercial solvents such as tetrahydrofuran (THF), dichloromethane, hexane, acetone, ethanol, methanol, toluene, ethyl acetate, dimethylsulfoxide and water were used without further purification.

Synthesis Example 1. 1,2-bis (4-hydroxybenzene) -3,4,5,6-tetraphenylbenzene [1,2-bis (4-hydroxybenzene) -3,4,5,6-tetraphenylbenzene , BHPTPB] Synthesis

The synthesis procedure of BHPTPB is shown in Reaction Scheme 2 below.

In a nitrogen atmosphere, 1,2-bis (4-dimethoxybenzene) -3,4,5,6-tetraphenylbenzene (18.6 mmol, 11.06.g) contained in 50 mL of dichloromethane was added to a three-necked flask equipped with a magnetic stirrer. Input. To this was added 10 mL of dichloromethane containing BBr ₃ (44.64 mmol, 4.23 mL) at 0 ° C. The solution was cooled in an ice bath and quenched with water. The layers were separated using ethyl acetate and 1M hydrochloric acid, and the aqueous layer was extracted with ethyl acetate. The combined organic extracts were washed with brine, dried over Na ₂ SO ₄ and concentrated.

At this time, if necessary, a general walk-up work can be performed. The quenched reaction was diluted with dichloromethane and extracted twice with 1N NaOH. The aqueous layer was acidified with concentrated hydrochloric acid and extracted twice with ethyl acetate. The composite organic layer was washed with brine, dried over Na ₂ SO ₄ and concentrated.

[Reaction Scheme 2]

Synthesis Example 2. Synthesis of poly (tetra phenyl ether sulfones), PTPES

A typical polycondensation process is shown in Scheme 3.

Monomer 1,2-bis (4-hydroxyphenyl)-prepared in Synthesis Example 1 in a 100 mL three-necked flask equipped with a Dean-Stark trap, a condenser, a nitrogen inlet / outlet and a magnetic stirrer. 3,4,5,6-tetraphenyl-benzene (BHPTPB) (0.73 g, 1.28 mmol), 4,4'-difluorophenylsulfone (1.63 g, 6.40 mmol), bis (4-hydroxyphenyl) sulfone (1.28 g, 5.12 mmol), K ₂ CO ₃ (1.06 g, 7.68 mmol), NMP (11 mL) and toluene (6 mL) were added thereto. The mixture was refluxed at 160-180 [deg.] C for 3 hours. After the obtained water became an azeotrope with chlorobenzene, the mixture was heated at 210 ° C. for about 1 hour until a high viscosity solution was obtained. After cooling the resulting mixture was poured into a methanol (100 mL) / water (100 mL) / HCl (10 mL) mixture to precipitate a white fibrous polymer. After that, the polymer was collected by filtration and washed with water. The polymer collected by filtration was dried in a vacuum oven at 80 ° C. for 24 hours.

¹ H NMR (400 MHz, DMSO-d ₆ ), δ = ppm: 7.79-8.09 (d, 12 H, 3 ortho C ₆ H ₂ SO ₂ C ₆ H ₂ ), 7.17-7.31, 6.80-7.00 (d, 12 H, 3 meta C ₆ H ₂ SO ₂ C ₆ H ₂ ), 6.66-7.00 (m, 28 H, 4 C ₆ H ₅ and 2 C ₆ H ₄ O), FT-IR: 1249 cm ^-1 , 1026 cm ^-1 , 690 cm ^-1 (stretching (OSO).

Synthesis Example 3 Synthesis of Chloromethylated Poly (Tetraphenyl Ether Sulfone) (CH ₂ Cl-PTPES)

Chloromethylation of PTPES was carried out in a 100 mL three-neck round bottom flask equipped with a condenser, nitrogen inlet / outlet and magnetic stirrer, respectively. Zinc chloride (0.51 g, 3.78 mmol) and thionyl chloride (1.00) in 1,1 ', 2,2'-tetrachloroethane (20 mL) containing PTPES (1.00 g, 1.89 mmol) prepared in Synthesis Example 2 mL, 13.70 mmol) was added at room temperature. After addition, chloromethyl ether (6.00 mL, 78.99 mmol) was added dropwise, after which the solution was stirred at room temperature for 12 hours. Chloromethylated PTPES (CH ₂ Cl-PTPES) was precipitated in methanol, washed several times with deionized water and methanol and dried in a vacuum oven at 80 ° C. for 24 hours.

¹ H NMR (400 MHz, DMSO-d ₆ ), δ = ppm: 7.79-8.09 (d, 12 H, 3 ortho C ₆ H ₂ SO ₂ C ₆ H ₂ ), 7.17-7.31, 6.80-7.00 (d, 12 H, 3 meta C ₆ H ₂ SO ₂ C ₆ H ₂ ), 6.64-7.02 (m, 24 H, 4 C ₆ H ₄ and 2 C ₆ H ₄ O), 4.28-4.60 (d, 8 H, 4 -CH ₂ Cl), FT-IR: 1249 cm ^-1 , 1026 cm ^-1 , 690 cm ^-1 (stretching (OSO).

Scheme 3

Example 1.Preparation of Poly (tetra phenyl ether sulfone)-(quaternary ammonium hydroxide) [PTPES-QAH 20]>

CH ₂ Cl-PTPES prepared in Synthesis Example 3 was subjected to quaternary ammonization (quarternization) reaction and Cl ⁻ was exchanged with OH ⁻ to prepare a PTPES-QAH copolymer.

More specifically, CH ₂ Cl-PTPES was dissolved in dimethylsulfoxide (DMSO) to prepare a 10 wt% solution. The solution was cast on a glass plate with a thickness of about 50 μm or less and then dried at 100 ° C. for 24 hours. In this case, the film having a thickness greater than 50 μm may not penetrate into the membrane. The cast electrolyte membrane was immersed in 30 wt% trimethylamine (TMA) solution at room temperature for 48 hours to allow quaternary ammonium chloride base to be introduced into the electrolyte membrane. At this time, the electrolyte membrane thickness was adjusted to be 50 μm or less (<50 μm). The polymer electrolyte membrane is in a strong and small amount impregnated form. To exchange Cl ⁻ anions in the polymer with OH ⁻ , the PTPES-QAC electrolyte membrane was immersed in 1M KOH solution for 48 hours and then washed several times with distilled water until the pH of the remaining water became neutral (PTPES-QAH 20 ).

¹ H NMR (400 MHz, DMSO-d ₆ ), δ = ppm: 7.75-8.15 (d, 12 H, 3 ortho C ₆ H ₂ SO ₂ C ₆ H ₂ ), 6.70-7.31 (b, 12 H, 3 meta C ₆ H ₂ SO ₂ C ₆ H ₂ ), 6.70-7.31 (b, 24 H, 4 C ₆ H ₄ and 2 C ₆ H ₄ O), 5.98-6.08 (b, 4 H, 4 OH ⁻ ), 4.18-4.59 (b, 8H, 4 -CH ₂ -N (CH ₃ ) ₃ ), 2.58-3.08 (b, 36H, 4 -CH ₂ -N (CH ₃ ) ₃ ), FT-IR: 1249 cm ^-1 , 1026 cm ^-1 , 690 cm ^-1 (stretching (OSO), (b, -OH near ⁺ N (CH ₃ ) ₃ ).

Example 2. Preparation of poly (tetra phenyl ether sulfone)-(quaternary ammonium hydroxide) [PTPES-QAH 15]

Monomer 1,2-bis (4-hydroxyphenyl) -3,4,5,6-tetraphenyl-benzene (BHPTPB) (0.54) prepared in Synthesis Example 1 in the preparation of poly (tetra phenyl ether sulfone) (PTPES) g, 0.96 mmol), 4,4'-difluorophenylsulfone (1.63g, 6.40 mmol), bis (4-hydroxyphenyl) sulfone (1.36g, 5.45 mmol), K ₂ CO ₃ (1.06g, 7.68 mmol), NMP (11 mL) and toluene (6 mL) were added, and the title aerial was carried out in the same manner as in Example 1, except that the mixture was prepared by refluxing at 160-180 ° C. for 3 hours. Copolymer (PTPES-QAH 15) was prepared.

Example 3. Preparation of Poly (tetra phenyl ether sulfone)-(quaternary ammonium hydroxide) [PTPES-QAH 25]>

Monomer 1,2-bis (4-hydroxyphenyl) -3,4,5,6-tetraphenyl-benzene (BHPTPB) (0.90) prepared in Synthesis Example 1 when preparing poly (tetra phenyl ether sulfone) (PTPES) g, 1.60 mmol), 4,4'-difluorophenylsulfone (1.63g, 6.40 mmol), bis (4-hydroxyphenyl) sulfone (1.20g, 4.80 mmol), K ₂ CO ₃ (1.06g, 7.68 mmol), NMP (11 mL) and toluene (6 mL) were added, and the title aerial was carried out in the same manner as in Example 1, except that the mixture was prepared by refluxing at 160-180 ° C. for 3 hours. Copolymer (PTPTES-QAH 25) was prepared.

<Measurement method and measuring device of electrolyte membrane>

The physical properties of the copolymers synthesized in the present invention were evaluated and measured by FT-IR, ¹ H-NMR spectroscopy, thermogravimetric analysis (TGA), proton conductivity, water absorption, and ion exchange ability (IEC), respectively.

For reference, the presence of CH ₂ Cl groups in chloromethylated PTPES and PTPES-QAH was demonstrated by ¹ H-NMR. In addition, different amounts of ammonium units in PTPES-QAH (15, 20, 25 mol% of BHPTPB) were determined by FT-IR, ¹ H-NMR spectroscopy, thermogravimetric analysis (TGA). Absorption experiments observed the interaction between PTPES-QAH and water. In addition, the ion exchange capacity and proton conductivity of PTPES-QAH were evaluated at different quaternization levels.

1) The structure of the polymer was verified by Fourier Transform infrared (FT-IR) spectroscopy. Measurements were recorded using a MIDAC FT-IR spectrometer with thin homogeneous cast films.

2) ¹ H NMR spectra were measured with a Bruker DRX (400 MHz) spectrometer, using DMSO-d6 and tetramethylsilane (TMS) as solvents and internal standards.

3) Thermogravimetric analysis (TGA) was performed with a Perkin-Elmer TGA7 analyzer. The electrolyte membrane was vacuum dried for 24 hours at 100 ° C., weighed, soaked in deionized water at room temperature, and left at 80 ° C. for 24 hours. The electrolyte membrane in the impregnated state was washed to dry and then quickly weighed again. Water absorption of the electrolyte membrane was recorded as weight percent as follows.

Water uptake = {(W _wet - W _dry ) / W _dry } × 100%

Here, W _wet and W _dry mean the weight of the electrolyte membrane in a wet state and a dry state, respectively.

4) ion exchange capacity (IEC): The IEC of polyelectrolytes was determined by titration. The PTPES-QAH electrolyte membrane (in OH ^- form) was immersed in a standard hydrochloric acid solution (0.10M, 25 mL) for 48 hours, and the solution was prepared with potassium hydroxide (0.10M) standard solution containing phenolphthalein (PP) indicator. Titration. The electrolyte membrane was washed and soaked in deionized water for 24 hours to remove residual HCl. After drying in a vacuum at 50 ℃ for 24 hours, the weight was measured to determine the dry mass (dry mass, in Cl ^- form). The IEC of the electrolyte membrane was calculated as follows:

IEC (meq./g) = (standard hydrochloric acid solution concentration)-(qualified KOH solution concentration) / mass of dried electrolyte membrane

5) Proton Conductivity: The proton conductivity of the electrolyte membrane was determined from the electrolyte membrane resistance measured by electrochemical impedance spectroscopy (EIS) using Bekktech membrane & single-cell test systems (BT-512). At this time, it proceeded at 40 ℃, 60 ℃, 80 ℃ under 100% humidity conditions. EIS proceeded by applying small AC voltage (10mV) under open circuit condition, and changed the frequency of the alternating voltage from 1 × 10 ⁵ to 1Hz.

Experimental Example 1. Evaluation of Structure and Physical Properties of PTPES-QAH Electrolyte Membrane>

1. Structure verification ( ^One H NMR)

(1) structure of PTPES ( ^One H NMR)

Poly (tetramethylene ether sulfone) series PTPES 15, 20 and 25 K ₂ CO ₃ in - was successfully synthesized by using a catalyzed aromatic nucleophilic substitution reaction (K ₂ CO ₃ -catalyzed nucleophilic aromatic substitution reaction), multi- -Phenylmonomer BHPTPB and 4,4'-difluorophenylsulfone and bis (4-hydroxyphenyl) sulfone were heated in NMP / toluene at 145 ° C. for 6 hours to remove water and then heated at 200 ° C. for 2 hours. To obtain a highly viscous reaction mixture. The feed mole ratio (feed mole fraction) of BHPTPB was varied to produce polymers with different degrees of quaternization. The structure of PTPES was determined by ¹ H NMR.

In FIG. 1 (a), the H _a peaks of ortho protons of sulfone were found at 7.95-8.09 ppm, and the H _b and H _c peaks of ortho protons of sulfone adjacent to the hepta phenyl moiety were found at 7.79-7.95 ppm. This is because of the electron donating effect of the phenyl ring. H _d peaks of metha protons of sulfone were found at 7.17-7.31 ppm and H _e peaks of ortho protons of sulfone adjacent to the hepta-phenyl moiety were found at 6.80-7.00 ppm. H _f peaks of hepta phenyl propones were found at 6.66-7.00 ppm, respectively. H _a, H _b, H _c, and H _d integration ratio of (the integration ratios) have been verified in a molar ratio of constituent components of the copolymer. In the FT-IR study, OSO stretching peaks were observed at 1249 cm ⁻¹ , 1026 cm ⁻¹ , and 690 cm ⁻¹ (see FIG. 2).

(2) CH ₂ Structure Verification of Cl-PTPES ( ^One H NMR)

Chloromethylated poly (tetra phenyl ether sulfone) copolymer (CH ₂ Cl-PTPES) was prepared by Friedel-Crafts chloromethylation reaction. The Friedel-Craft chloromethylation reaction of polymers should be carefully validated from various variables such as the concentration of the polymer, the type and content of chloromethylmethyl ether, Lewis acid catalysts (zinc chloride and thionyl chloride), reaction time and temperature, etc. . We found that the reaction temperature, the ratio of chloromethylmethyl ether and the amount of Lewis acid catalyst for PTPES were important. The reaction was terminated with 30 ° C., a mixture of zinc chloride and thionyl chloride (mole ratio of 1: 3.6), and a 40: 1 molar ratio of chloromethylmethylether: PTPES being the most effective condition without gelation. Under single Lewis acid catalyst conditions, the reaction was slow and lacked chloromethylation.

The structure of CH ₂ Cl-PTPES was verified by ¹ H NMR.

In Figure 1 (b) below, the H _a peaks of ortho protons of sulfone are found at 7.93-8.09 ppm, and the H _b and H _c peaks of ortho protons of sulfone adjacent to the chloromethylated hepta phenyl moiety are 7.75-7.93 It was found in ppm because of the electron donating effect of the phenyl ring. The H _d peaks of the metha protons of sulfone were found at 7.20-7.31 ppm and the H _e peaks of the ortho protons of sulfone adjacent to the chloromethylated hepta-phenyl moiety were found at 6.60-7.10 ppm. H _f peaks of chloromethylated hepta-phenyl protons were found at 7.10-7.20 and 6.60-7.10 ppm, respectively. The Hg peaks of the methylene protons of the chloromethyl group appeared new at 4.28-4.60 ppm. Chloromethylation yield is selected from 5-positional protons in hepta phenyl group under optimized reaction conditions, methylene protons of chloromethyl group at (4.28-4.60 ppm) versus protons of total phenyl at (6.60-8.09 ppm) It was predicted from the integral ratio of. In the FT-IR study, OSO stretching peaks were observed at 1249 cm ⁻¹ , 1026 cm ⁻¹ , 690 cm ⁻¹ (see FIG. 2).

(3) Verification of the structure of PTPES-QAH ( ^One H NMR)

The structure of PTPES-QAH prepared in Example 1 was verified by ¹ H NMR.

In FIG. 1 (c), the H _a to H _f peaks of the protons of CH ₂ Cl-PTPES appeared broad at the same location. At this time, the appearance of a peak (H _h , 2.58-3.08 ppm, 36 H, 4 N (CH ₃ ) ₃ ) means that the chloromethyl group was modified to a quaternary ammonium group. Size ratio of peak (H _h , 2.58-3.08 ppm, 36 H, 4 N (CH ₃ ) ₃ ) to peak (H _g , 4.18-4.59 ppm, 8 H, 4 -CH ₂ -N (CH ₃ ) ₃ ) (intensity ratio) tended to be close to 2: 9, which is in good agreement with the ratio of the hydrogen atoms of the first methylene group to the hydrogen atoms of the newly bonded quaternary ammonium group. More specifically, there is no aliphatic beta hydrogen atom around the quaternary ammonia group, which is the most important feature for avoiding the Hoffmann degradation reaction leading to loss of functional groups. These results also indicate that the conversion of chloromethyl groups to quaternary ammonium groups is nearly complete. And H _i peaks of the hydroxide anion (OH ⁻ ) can be observed at 5.98-6.08 ppm.

In the FT-IR study, the absorption characteristics at 1249 cm ^-1 , 1026 cm ^-1 , and 690 cm ^-1 are shown to be stretching vibration (OSO), and C = O stretching peaks can be observed at 1710 cm ^-1 . there was. The broad peak at 3500 cm ⁻¹ is shown as —OH of the water molecule surrounding sulfuric acid and sulfuric acid groups (see FIG. 2 below). These results are understood as the structure of PTPES-QAH.

2. Evaluation of Thermogravimetric Analysis of PTPES-QAH

Thermal-oxidation stability of PTPES and PTPES-QAH prepared in Synthesis Example 2 and Example 1, respectively, was evaluated using thermogravimetric analysis (TGA). Their results are shown in Figures 3 and 4 below.

The PTPES copolymer was thermally stable up to 450 ° C. and the resulting alkali polymers showed good high temperature thermal stability under atmospheric conditions. Initial weight loss in the 50-160 ° C. range is due to residual solvent (DMSO) and water release from PTPES-QAH. Secondary weight loss above 180 ° C. is due to decomposition of the methyl quaternary ammonium base and chloromethyl groups. The third weight loss at 450 ° C. is due to the decomposition of the polymer backbone.

3. Ion Exchange Capability (IEC) Evaluation of PTPES-QAH

The PTPES-QAH copolymer is dissolved in semiprotic polar solvents such as DMSO, DMAc, and NMP, and the DMSO solution is cast to form a pale yellow transparent film. PTPES-QAH containing quaternary ammonium hydroxide bases to different degrees was prepared as the amount of monomer BHPTPB introduced into the backbone to determine the ion exchange capacity (IEC) affecting proton conductivity. The degree of quaternization is expressed in the form of ion exchange capacity (IEC: meq./g).

The increase in the number of quaternary ammonium hydroxide groups introduced into the polymer not only improves their ionic conductivity but also makes the polymer more hydrophilic. In order to obtain an electrolyte membrane suitable for an alkaline fuel cell (AFC), it must have sufficient quaternary ammonium hydroxide groups to provide suitable proton conductivity while maintaining the mechanical form.

As shown in FIG. 5 below, the ion exchange capacity (IEC) of PTPES-QAH was 1.31, 1.57, 2.00 meq./g. . Also, to increase the percentage of quaternary ammonium hydroxide groups, the IEC of the PTPES-QAH electrolyte membrane was increased. Theoretical and titrated IECs ideally matched the form (see Table 1).

Polymer PTPES-QAH 15
(Example 2) PTPES-QAH 20
(Example 1) PTPES-QAH 25
(Example 3) Theory IEC (meq./g) 1.30 1.62 1.91 Proper IEC (meq./g) 1.31 1.57 2.00 Moisture Content (WU)
at 30 ℃ (%) 25.30 45.47 87.82 Moisture Content (WU)
at 80 ℃ (%) 38.65 53.90 116.45 Δ t (%) 24.25 33.05 62.68 Δ 1 (%) 28.85 39.25 73.54 Ion conductivity (mS / cm) 9.11 13.30 19.55 ※ Proton conductivity is measured at 100% RH, 80 ℃.

4. PTPES - QAH Water content ( WU ) evaluation

FIG. 5 shows the water absorption (WU) of the PTPES-QAH electrolyte membrane as a function of the degree of quaternization at room temperature and 80 ° C. FIG. In PTPES-QAH electrolyte membranes where the IEC increased from 1.31 to 2.00 meq./g, the water content increased from 25.3% to 87.82% at room temperature and from 38.65% to 116.45% at 80 ° C.

The water content (WU) is highly dependent on the ion exchange capacity (IEC), so the number of sorbed water molecules per ammonium group (λ) is related to the polymer structure and WU. It is used for evaluation. λ can be calculated from Equation 1 below.

[Equation 1]

λ = (10 × WU) / (IEC × 18)

In PTPES water, λ ranges from 16.4 to 3.33 at 80 ° C. A high degree of degree of hydroxide (DH) makes the electrolyte membrane more hydrophilic and hydrates it with water, which acts as a plasticizer. PTPES-QAH electrolyte membranes with high IEC mainly result in high moisture content of the electrolyte membranes, and furthermore, mechanical properties decrease due to large dimensional change in the electrolyte membranes. Dimensional changes of PTPES-QAH electrolyte membranes can be evaluated by comparing their hydration and dry conditions.

The through-plane and in-plane (Δt and Δl, respectively) of electrolyte membrane impregnation in water at 80 ° C. can be summarized in Table 1. It should be noted that all PTPES-QAH electrolyte membranes show an electrolyte membrane impregnation pattern with Δl larger than Δt. Small changes in through-plane with high proton conductivity are desirable aspects to maintain dimensional stability while the PEMFC stack is operating. Side chain sulfonated polymer electrolyte membranes have been reported, showing anisotropic membrane swelling with larger dimensional changes in thickness direction than in plane. This is due to their flexible side chains and solid backbone structure. And also flexible ether bonds in the main chain tend to interfere with the alignment of the polymer chains, resulting in a greater degree of impregnation of the anisotropic electrolyte membrane than the rigid chain electrolyte membrane.

5. Evaluation of Ionic Conductivity of PTPES-QAH

Ionic conductivity of the PTPES-QAH series was measured as a mole fraction function of ammonium hydroxide units (see FIG. 6).

As expected, the ionic conductivity of the polymers also increased as the ammonium hydroxide content increased from 15% to 25%. As a result, the PTPES-QAH electrolyte membranes showed a range of 9.10-19.55 mS / cm at 80 ° C under 100% humidity, and the ion exchange capacity (IEC) increased as the degree of ammonium hydroxide increased. The conductivity values and other properties of PTPES-QAH are considered to be useful when considering the performance aspects of fuel cells compared to previously reported APEFCs.

Claims (16)

Poly (tetraphenyl ether) sulfone copolymer containing a quaternary ammonium hydroxide group in the repeating unit represented by the following formula (1):
[Chemical Formula 1]

In this formula,
Ar ₁ is

or

ego,
E is a single bond, O, S, C (= O), S (= O), S (= O) 2, C (CH 3) 2, C (CF 3) 2, Si (CH 3) 2, P and (= O) CH ₃ or C (= O) NH,
Z ₁ and Z ₂ are different from or equal to each other, and each independently hydrogen or an alkyl group of C ₁ ~ C _6, said C ₁ ~ C ₆ alkyl group may be substituted with a halogen, a cyano group or a sulfone,
R is an alkyl group of C ₁ ~ C _6,
R ₁ to R ₄ are the same as or different from each other, and each independently hydrogen or an aromatic group, two or more of them are aromatic groups, and R ₁ to R ₄ are substituted with two or more quaternary ammonium hydroxide groups,
x is 0.01 to 1,
m is 0.1 to 0.9, and n is 0.9 to 0.1. The poly (tetraphenylether) sulfone copolymer according to claim 1, wherein R ₁ to R ₄ are phenyl groups substituted with four or more quaternary ammonium hydroxide groups. 2. The method of claim 1, wherein E is S (= O _2), and, Z ₁ and Z ₂ is a hydrogen atom, R is CH ₂ N (CH _{3) 3,} and, R ₁ to R ₄ is 4 to 8 4 A poly (tetraphenylether) sulfone copolymer, wherein phenyl is substituted with a class ammonium hydroxide group, x is 0.5, m is from 0.1 to 0.9, and n is from 0.9 to 0.1. The poly (tetraphenyl ether) sulfone copolymer according to claim 1, wherein the copolymer is represented by the following Chemical Formula 2.
(2)

In this formula,
m is 0.1 to 0.9, and n is 0.9 to 0.1. A polymer electrolyte membrane comprising the poly (tetraphenyl ether) sulfone copolymer according to any one of claims 1 to 4. According to claim 5, wherein the hydroxyl group (OH ^-) anion exchange electrolyte membrane for conducting the ionic polymer electrolyte membrane according to claim. The polymer electrolyte membrane of Claim 5, wherein the electrolyte membrane further comprises at least one polymer selected from the group consisting of polysulfone, polyether ketone, polyether ether ketone, and polybenzimidazole-based polymer. 6. The method of claim 5, the group consisting of the electrolyte membrane of silica (SiO _2), titania (TiO _2), an inorganic acid, sulfonated silica, sulfonated zirconium oxide (ZrO), and set the zirconium phosphate (ZrP) sulfonate Wherein the polymer electrolyte membrane further comprises at least one inorganic substance selected from the group consisting of an alkali metal salt and an alkali metal salt. The polymer electrolyte membrane according to claim 5, wherein the electrolyte membrane further comprises a porous support. A membrane electrode assembly (MEA) comprising the polymer electrolyte membrane of claim 5. A fuel cell comprising the polymer electrolyte membrane according to claim 5. 12. The fuel cell of claim 11, wherein the fuel cell is an alkaline fuel cell. (i) polymerizing a polymer represented by Formula 6 by polymerizing a multiphenyl monomer represented by Formula 3, a dihydroxy monomer of Formula 4, and a dihalide monomer of Formula 5;
(Ii) chloromethylating the polymer of Formula 6 to synthesize a polymer of Formula 7; And
(Iii) quaternary ammoniumation of the polymer of formula (7) and treatment with alkaline solution
Method for producing a poly (tetraphenyl ether) sulfone copolymer represented by the formula (1) comprising:
[Reaction Scheme 1]

In the above Reaction Scheme 1,
X is F, Cl, Br, or I,
R ₅ to R ₈ are the same or different from each other and each independently represents hydrogen or an aromatic group, at least two of them are aromatic groups,
R ₉ to R ₁₂ are the same as or different from each other, and each independently hydrogen or an aromatic group, at least two of which are aromatic groups, and R ₉ to R ₁₂ are substituted with two or more chloromethyl groups,
Y is a chloromethyl group (CH ₂ Cl),
Ar ₁ , R ₁ to R ₄ , R, x, m, n are as defined in claim 1. The method according to claim 13, wherein all of R ₅ to R ₈ are phenyl groups. The method according to claim 13, wherein step (ii) is carried out in the presence of at least one Lewis acid catalyst selected from the group consisting of ZnCl ₂ and SOCl ₂ , chloromethylating the compound of formula 6 with a chloromethylating agent at 30 to 90 ° C. Characterized in the manufacturing method. The method of claim 15, wherein the molar ratio of ZnCl ₂ : SOCl ₂ is in the range of 1: 3.6 to 4.0, and the molar ratio of the chloromethylating agent to the compound of formula 6 is in the range of 38 to 42: 1.

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