KR20090067847A - Electrolyte Membrane Using Water-Soluble Polymer and Crosslinkable Multiblock Copolymer - Google Patents

Abstract

The present invention relates to an electrolyte membrane using a water-soluble polymer and a crosslinkable multiblock copolymer. More specifically, the present invention relates to a di-block copolymer or a sulfonic acid group composed of a hydrophobic block and a crosslinkable block having a crosslinkable functional group. The water-soluble polymer having a functional group capable of crosslinking with the crosslinkable block of the tri-block copolymer to which the hydrophilic block is further bonded is crosslinked by a crosslinking agent, which has stable mechanical and chemical properties and high ionic conductivity, and according to a simple synthesis process. The present invention relates to a crosslinked block polymer blended electrolyte membrane for a fuel cell produced.

Description

Electrolytic membranes comprising soluble polymers and crosslinkable multi-block copolymers

The present invention relates to an electrolyte membrane using a water-soluble polymer and a crosslinkable multiblock copolymer. More specifically, the present invention relates to a di-block copolymer or a sulfonic acid group composed of a hydrophobic block and a crosslinkable block having a crosslinkable functional group. The water-soluble polymer having a functional group capable of crosslinking with the crosslinkable block of the tri-block copolymer to which the hydrophilic block is further bonded is crosslinked by a crosslinking agent, which has stable mechanical and chemical properties and high ionic conductivity, and according to a simple synthesis process. The present invention relates to a crosslinked block polymer blended electrolyte membrane for a fuel cell produced.

A polymer electrolyte membrane commonly used to date is a perfluorosulfonic acid based ion exchange membrane having a sulfonic acid group (-SO ₃ H), and the chemical structure of the membrane is represented by the following Chemical Formula X.

[Formula X]

Where

The ratio of x and y is 20: 1 to 2: 1, and is an integer of m = 0, 1, or 2, n = 1-12.

For example, Nafion membrane from Du Pont, Dow chemical membrane from Dow Chemical, Flemion membrane from Asahi Glass, Aciplex from Asahi Chemical (Aciplex), Ballard's Bam's film, or Gore's Primea's film are mainly used.

In addition, perfluorosulfonic acid-based membranes are well received for their high ionic conductivity and excellent mechanical and chemical stability. Holding it. Therefore, the synthesis of a polymer electrolyte membrane, which is simple and inexpensive, maintains high hydrogen ion conductivity, and has excellent mechanical and chemical properties, is one of the goals pursued by the polymer electrolyte fuel cell. have.

As a general method for preparing a polymer electrolyte, a sulfonic acid group may be introduced into a polymer containing a benzene group by a sulfonation reaction. However, this method typically has much lower acidity of these sulfonic acid groups than Nafion's fluorosulfonic acid groups, so that satisfactory conductivity can be obtained only by reaching extremely high sulfonation degrees. However, when the sulfonation degree is very high, it may cause mechanical strength and solubility problems of the polymer membrane.

As a method for obtaining high ionic conductivity while maintaining the mechanical strength of the polymer electrolyte membrane, many studies have been conducted on the development of a block copolymer electrolyte (WO 2004/042839) and a cross-linked copolymer electrolyte membrane (Korean Patent No. 10-0453680). there was. The copolymer comprising a structural unit capable of causing a crosslinking reaction and a structural unit substituted by an ion conductive group constitutes an electrolyte membrane crosslinked with each other, so that the conductivity of hydrogen ions is less affected by moisture and methanol, and methanol crossover The solution could be used in various electrochemical devices including fuel cells.

However, there is still a need for a polymer electrolyte membrane which is not easily broken when dried or expanded, and can be used not only for general fuel cells but also for direct methanol fuel cells using methanol as a fuel while improving existing complex synthesis processes.

SUMMARY OF THE INVENTION The present invention has been made to solve the problems of the prior art, and an object of the present invention is to provide a block polymer that is easy to manufacture, has excellent hydrogen ion conductivity and mechanical properties, and is chemically stable.

Another object of the present invention is to provide a hydrogen ion conductive polymer electrolyte membrane for a fuel cell, including the block polymer having the above excellent physical properties, which is not easily broken even when dried or expanded.

It is yet another object of the present invention to provide fuel cells and other electrochemical devices comprising electrolyte membranes having such excellent hydrogen ion conductivity.

In order to achieve the above object, the present invention

Block copolymers comprising a hydrophobic block and a crosslinkable block having a crosslinkable functional group;

Water-soluble polymers having a crosslinkable functional group; And

Including crosslinkers having sulfonic acid groups,

It provides a crosslinkable block polymer characterized in that the crosslinkable block and the water-soluble polymer of the block copolymer is crosslinked through the crosslinking agent.

The block copolymer may further comprise a hydrophilic block having sulfonic acid groups.

The present invention also provides a first step of preparing a block copolymer comprising a hydrophobic block and a crosslinkable block having a crosslinkable functional group; And

It provides a method for producing a crosslinkable block polymer comprising a second step of crosslinking the crosslinkable block and a water-soluble polymer having a crosslinkable functional group using a crosslinking agent having a sulfonic acid group.

The present invention also provides an electrolyte membrane comprising the crosslinkable block polymer having the above excellent physical properties.

The present invention also provides a fuel cell and an electrochemical device comprising the crosslinked block polymer blended electrolyte membrane.

The present invention has thermal, mechanical and chemical stability because of using a crosslinked polymer electrolyte membrane composed of a water-soluble polymer and a crosslinkable multi-block copolymer, and has high ion conductivity, low fuel permeability, low dehydration effect, and low gas permeability. The simple synthesis process has the effect of substantially reducing the manufacturing cost and manufacturing time.

EMBODIMENT OF THE INVENTION Hereinafter, the structure of this invention is demonstrated concretely.

The present invention

Block copolymers comprising a hydrophobic block and a crosslinkable block having a crosslinkable functional group;

Water-soluble polymers having a crosslinkable functional group; And

Including crosslinkers having sulfonic acid groups,

It relates to a crosslinkable block polymer characterized in that the crosslinkable block of the block copolymer and the water-soluble polymer are crosslinked through the crosslinking agent.

The hydrophobic block is not particularly limited as long as it is a high molecular polymer including a hydrophobic group, but preferably includes a repeating unit represented by the following Chemical Formula 1 or Chemical Formula 2.

[Formula 1]

[Formula 2]

Where

R ₁ represents hydrogen or an alkyl group having 1 to 4 carbon atoms,

R ₂ represents a cyano group, an alkyl group having 1 to 4 carbon atoms or an unsubstituted aryl group having 6 to 12 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, or -C (O) -X,

X represents an alkoxy group or amino group having 1 to 8 carbon atoms,

R ₃ represents hydrogen or an alkyl group having 1 to 4 carbon atoms,

n is an integer of 1-4.

As the hydrophobic block, polystyrene, polyalkylstyrene, polymethacrylate, polyacrylate, polyisoprene, polybutadiene, polyacrylamide, polyvinyl ether, or the like may be used alone or in combination.

The hydrophobic block is preferably included in 10 to 30 parts by weight based on 100 parts by weight of the total crosslinkable block polymer. If the content is in the above range, it is better in the thermal, mechanical, chemical stability of the crosslinkable block polymer.

In addition, it is preferable that the crosslinkable functional group of a crosslinkable block uses a hydroxyl group. More specifically, the crosslinkable block preferably includes a repeating unit represented by the following formula (3).

[Formula 3]

Where

R ₄ represents hydrogen or an alkyl group having 1 to 4 carbon atoms,

R ₅ represents a hydroxy group, an aryl group having 6 to 12 carbon atoms substituted with a hydroxy group, an alkoxy group having 1 to 8 carbon atoms substituted with a hydroxyl group, or -C (O) -X,

X represents the C1-C8 alkoxy group substituted by the hydroxy group, or the amino group substituted by the hydroxy group or the C1-C3 alkoxy group here.

The crosslinkable block may include polyhydroxy methacrylate, polyhydroxy acrylate, polyhydroxy methacrylamide, polyhydroxy acrylamide, polyvinylphenol, polyvinyl alcohol, polyethylene glycol, or polypropylene glycol alone or the like. Two or more kinds can be used.

The crosslinkable block is preferably included in 10 to 30 parts by weight based on 100 parts by weight of the total crosslinkable block polymer. If the content is in the above range, it is better in the thermal, mechanical, chemical stability of the crosslinkable block polymer.

In addition, the block copolymer may further include an ion conductive hydrophilic block having sulfonic acid groups. Preferably, it is preferable to include a repeating unit represented by the following formula (4).

[Formula 4]

Where

R ₆ represents hydrogen or an alkyl group having 1 to 4 carbon atoms,

R ₇ is an aryl group having 6 to 12 carbon atoms substituted with a sulfonic acid group, an alkyl group having 1 to 8 carbon atoms substituted with a sulfonic acid group, an alkoxy group having 1 to 8 carbon atoms substituted with a sulfonic acid group, or -C (O) -X Indicates,

X represents an alkoxy group having 1 to 8 carbon atoms substituted with a sulfonic acid group.

The hydrophilic block having the sulfonic acid group includes polystyrene sulfonic acid, polymethyl propene sulfonic acid, polysulfopropyl methacrylate, polysulfoethyl methacrylate, poly sulfobutyl methacrylate, polysulfopropyl acrylate, polysulfoethyl acrylate, Or polysulfobutyl acrylate etc. can be used individually or 2 types or more.

The hydrophilic block is preferably included in 10 to 30 parts by weight based on 100 parts by weight of the total crosslinkable block polymer. If the content is in the above range, it is better in the thermal, mechanical, chemical stability of the crosslinkable block polymer.

Moreover, it is preferable to use the hydroxyl group for the crosslinkable functional group of the said water-soluble polymer. More specifically, the water-soluble polymer preferably includes a repeating unit represented by the following formula (5).

[Formula 5]

Where

R ₈ represents hydrogen or an alkyl group having 1 to 4 carbon atoms,

R ₉ represents a hydroxy group, an aryl group having 6 to 12 carbon atoms substituted with a hydroxy group, an alkoxy group having 1 to 8 carbon atoms substituted with a hydroxyl group, or -C (O) -X,

X represents the C1-C8 alkoxy group substituted by the hydroxy group, or the amino group substituted by the hydroxy group or the C1-C3 alkoxy group here.

As the water-soluble polymer, polyvinyl alcohol, polyethylene glycol, polyacrylamide, polyethylene oxide, or the like may be used alone or in combination of two or more.

The water-soluble polymer is preferably included in 40 to 80 parts by weight based on 100 parts by weight of the total crosslinkable block polymer. If the content is in the above range, it is better in the thermal, mechanical, chemical stability of the crosslinkable block polymer.

In addition, the crosslinking agent having a sulfonic acid group may include one or more carboxyl groups, preferably a compound of formula 6 or 7.

[Formula 6]

[Formula 7]

Where

n represents the integer of 1-10.

The crosslinking agent is preferably included in 10 to 30 parts by weight based on 100 parts by weight of the total crosslinkable block polymer. If the content is in the above range, it is better in the thermal, mechanical, chemical stability of the crosslinkable block polymer.

The invention also

Preparing a block copolymer comprising a hydrophobic block and a crosslinkable block having a crosslinkable functional group; And

And a second step of crosslinking the crosslinkable block with a water-soluble polymer having a crosslinkable functional group using a crosslinking agent having a sulfonic acid group.

The crosslinkable block polymer includes a water-soluble polymer and a block copolymer, and the crosslinkable block of the water-soluble polymer and the block copolymer contains a hydroxy group, and crosslinks by an ester reaction with a crosslinking agent containing a carboxyl group. To form. The crosslinker also includes sulfonic acid groups to further provide hydrogen ion conductivity.

In addition, the block copolymer is a di-block copolymer composed of a hydrophobic block and a crosslinkable block having a crosslinkable functional group or a tri-block copolymer further combining a hydrophilic block having a sulfonic acid group to the di-block copolymer. It is preferable to prepare.

The block copolymer may be prepared through a polymer production reaction having a uniform molecular weight while removing substances such as undesired homopolymers and chain decomposition products through controlled free radical polymerization.

The controlled free radical polymerization includes atomic transfer radical polymerization (ATRP), nitroxide-mediated polymerization (NMP), reversible addition-fragmentation chain transfer (RAFT), anionic polymerization, and cationic polymerization cationic polymerization, etc., but is not particularly limited thereto.

The present invention also relates to a polymer electrolyte membrane comprising the crosslinkable block polymer.

The polymer electrolyte membrane is a member material existing between the negative electrode (fuel electrode) and the positive electrode (air electrode) inside the fuel cell constituting the power generation portion of the fuel cell. The hydrogen gas on the negative electrode side does not pass, and only protons (ionized hydrogen) are used. It is in charge of the function of conducting from the cathode side toward the anode side.

In addition, the polymer electrolyte membrane of the present invention exhibits a microphase separated structure, and is characterized by higher mechanical, chemical, thermal properties, and ionic conductivity than conventional polymer electrolyte membranes.

In addition, the thickness of the polymer electrolyte membrane is not particularly limited, but if the thickness is too thin, the strength of the polymer electrolyte membrane may be excessively reduced, and if the thickness is too thick, the internal resistance of the fuel cell may be excessively increased. In consideration of this point, the thickness of the polymer electrolyte membrane is preferably 30 to 200 μm.

The invention also

Cathode;

Anode; And

A fuel cell comprising the polymer electrolyte membrane of the present invention located between the cathode and the anode.

The polymer electrolyte membrane of the present invention can be used for a polymer electrolyte membrane fuel cell (PEMFC) for supplying a gas containing hydrogen to the anode, a direct methanol fuel cell (DMFC) for supplying a mixed vapor of methanol and water, or an aqueous methanol solution to the anode.

The cathode includes a catalyst layer for promoting a reduction reaction of oxygen, and the catalyst layer may include a polymer having a catalyst particle and a cation exchange group. In this case, a platinum catalyst, a platinum supported carbon catalyst (Pt / C catalyst), or the like may be used as the catalyst.

The anode includes a catalyst layer for promoting an oxidation reaction of a fuel such as hydrogen, methanol, ethanol, and the like, and the catalyst layer may include a catalyst particle and a polymer having a cation exchange group. At this time, as a catalyst, a platinum catalyst, a platinum-ruthenium catalyst, a platinum-supported carbon catalyst, a platinum-ruthenium-supported carbon catalyst, and the like may be used.A platinum-ruthenium catalyst or a platinum-ruthenium-supported carbon catalyst may be used as the catalyst. This is useful when feeding directly.

The catalyst used in the cathode and the anode may be a catalyst metal particle itself or a supported catalyst including the catalyst metal particles and the catalyst carrier. As the catalyst carrier, solid particles having conductivity such as carbon powder and having micropores capable of supporting catalytic metal particles may be used.

As the carbon powder, carbon black, acetylene black, activated carbon powder, carbon nanofiber powder, or a mixture thereof may be used.

The catalyst layer of the cathode and the anode is in contact with the polymer electrolyte membrane.

The cathode and the anode may further include a gas diffusion layer in addition to the catalyst layer. The gas diffusion layer includes a porous material having electrical conductivity, and serves as a current collector and an access passage of reactants and products.

As the gas diffusion layer, carbon paper, preferably water-repellent carbon paper, and more preferably water-repellent carbon paper coated with a water-repellent carbon black layer may be used.

The water-repellent treated carbon paper contains a hydrophobic polymer such as PTFE (polytetrafluoroethylene), and the hydrophobic polymer is sintered.

At this time, the water repellent treatment of the gas diffusion layer is to secure the access passage for the polar liquid reactant and the gas reactant at the same time.

In the water-repellent treated carbon paper having the water-repellent treated carbon black layer, the water-repellent treated carbon black layer contains a hydrophobic polymer such as PTFE as carbon black and a hydrophobic binder, and adheres to one side of the water-repellent treated carbon paper. The hydrophobic polymer of the water repellent treated carbon black layer is sintered.

The cathode and the anode may be prepared according to a conventional method, but are not particularly limited.

Fuels that can be supplied to the anode of the fuel cell of the present invention include hydrogen, methanol, ethanol, and the like, preferably liquid fuels containing polar organic fuel and water, and more preferably methanol aqueous solution. In this case, methanol, ethanol, or the like may be used as the polar organic fuel.

In the fuel cell of the present invention, since the crossover phenomenon of the polar organic fuel is suppressed by the polymer electrolyte membrane, a higher aqueous methanol solution can be used. In addition, even when a low concentration of methanol aqueous solution is used, the crossover phenomenon of the polar organic fuel is further suppressed by the polymer electrolyte membrane, and the polymer electrolyte membrane has excellent hydrogen ion conductivity, so that the fuel cell of the present invention is substantially Has improved life and efficiency.

The present invention also relates to an electrochemical device comprising the polymer electrolyte membrane of the present invention.

Electrochemical devices include, but are not limited to, electrolysis, electrodialysis, diffusion dialysis, pressure dialysis, chloro-alkali separators, batteries, and the like.

Hereinafter, the present invention will be described in detail through examples. However, the following examples are only for illustrating the present invention in detail and are not intended to limit the scope of the present invention by these examples.

Example 1 Preparation of Multi-Block Copolymer

1) Preparation of Hydrophobic Block Polymer (Polystyrene Homopolymer)

To 20 g of styrene at room temperature, 0.29 g of copper chloride and 1.24 mL of hexamethyltriethylenetetramine (Aldrich, USA) were added.

Nitrogen was injected for 30 minutes while stirring the solution, followed by addition of 0.22 mL of methyl 2-bromo-propionate (99%, Aldrich, USA).

The solution was infused with nitrogen for 30 minutes with stirring and placed in an oil bath preheated to 110 ° C. and reacted for 5 hours.

70 mL of tetrahydrofuran (THF, Aldrich Co., Ltd.) was added to the polymer after the reaction was diluted, and the solution was precipitated in methanol and filtered to recover the polymer. The polymer was re-dissolved in toluene, reprecipitated three times in methanol solvent and purified to recover the polymer. The high polymer was vacuum dried at room temperature for 24 hours.

2) Preparation of di-block copolymers (dBC, polystyrene-polyhydroxyethylacrylate di-block copolymers) consisting of hydrophobic blocks and crosslinkable blocks

5 g of the polystyrene prepared above was dissolved in 10 mL of toluene at 1 atmosphere of room temperature, and stirred at 25 ° C for 1 hour.

5 g (4.52 mL) of hydroxylethyl acrylate (HEA, Aldrich, USA) was added to the solution, and the two solutions were mixed and stirred with each other when sufficiently dissolved to prepare a uniform solution.

0.015 g of copper chloride and 0.0625 mL of hexamethyltriethylenetetraamine were added to the mixed solution, nitrogen was injected for 30 minutes while stirring, placed in an oil bath preheated to 80 ° C., and reacted for 8 hours.

The polymer solution after the reaction was precipitated in methanol (volume ratio = 1: 1) solvent and filtered to recover the polymer polymer. The polymer was re-dissolved in normal methylpyrrolidone (NMP, Aldrich, USA) and purified by re-precipitation three times in methanol-nucleic acid solvent to recover the polymer. The high polymer was vacuum dried at room temperature for 24 hours.

3) Preparation of tri-block copolymers (tBC, polystyrene-polyhydroxyethylacrylate-polystyrenesulphonic acid tri-block copolymers) of hydrophobic blocks, crosslinkable blocks and hydrophilic blocks

5 g of the polystyrene-polyhydroxyethyl acrylate di-block copolymer prepared above was dissolved in 50 mL of normal methylpyrrolidone at room temperature at 1 atmosphere, and dissolved by stirring at 25 ° C. for 1 hour.

5 g of styrene sulfonic acid sodium salt (SSA, Aldrich, USA) was separately dissolved in 25 mL of DMSO.

When the two solutions were sufficiently dissolved, they were mixed and stirred to prepare a uniform solution. Then, 0.015 g of copper chloride and 0.0625 mL of hexamethyltriethylenetetraamine were added to the mixed solution. The solution was infused with nitrogen for 30 minutes with stirring and placed in an oil bath preheated to 110 ° C. and reacted for 24 hours.

The polymer solution after the reaction was precipitated in methanol-nucleic acid (1: 1 volume ratio) solvent and filtered to recover the polymer. The polymer was redissolved in DMSO and repurified three times in methanol-nucleic acid solvent to recover the polymer. The high polymer was vacuum dried at room temperature for 24 hours.

Example 2 Preparation of Cross-linked Electrolyte Membrane Using Water-Soluble Polymer and Di-Block Copolymer (Polyvinyl Alcohol / Polystyrene-Polyhydroxyethyl Ethyl Di-Block Copolymer)

1 g of the polystyrene-polyhydroxyethyl acrylate di-block copolymer (dBC) prepared above was dissolved in 30 mL of DMSO, and then dissolved by stirring at 25 ° C. for 1 hour.

Next, 0.5 g of polyvinyl alcohol (polyvinyl alcohol, PVA, Mw = 85,000 g / mol) was separately dissolved in 7.5 mL of DMSO.

When the two solutions were sufficiently dissolved, they were mixed and stirred with each other to prepare a uniform solution. Then, to the solution was added 0.15 mL of sulfosuccinic acid (SA, 70% aqueous solution, Aldrich, USA) (dBC: PVA: SA = 20: 10: 3 weight ratio), followed by stirring for 30 minutes.

The solution was poured into a glass dish, a glass dish was put in a drying oven at 80 ° C. to remove solvent for two days, and then the remaining solvent was completely removed from the vacuum oven. The polymer membrane was heat-treated in a drying oven at 120 ° C. to obtain a crosslinked polymer membrane.

The polymer membrane was precipitated in 1 N aqueous sulfuric acid solution for one day to replace sodium cations with hydrogen ions. The polymer membrane was washed 10 times with distilled water to make the solution neutral and the ion conductivity was measured at 25 ° C. The results are shown in Table 1.

<Example 3>

A polymer electrolyte membrane was prepared in the same manner as in Example 2 except that 1 g of PVA (dBC: PVA: SA = 15: 15: 3 weight ratio) was dissolved in 15 mL of DMSO, and then ion conductivity was measured. The results are shown in Table 1.

<Example 4>

A polymer electrolyte membrane was prepared in the same manner as in Example 2, except that 2 g of PVA (dBC: PVA: SA = 10: 20: 3 weight ratio) was dissolved in 15 mL of DMSO, and then ionic conductivity was measured. The results are shown in Table 1.

(Ion Conductivity Measurement Experiment of Polymer Electrolyte Membrane)

The prepared polymer electrolyte membrane was washed 10 times with distilled water and then dried, and the ion conductivity of the prepared polymer electrolyte membrane was measured using a 4-pole electrode device. The polymer electrolyte membrane prepared between the four electrodes was placed to maximize contact with the electrodes, and the terminals of the electrodes were connected to an AC impedance analyzer (IM6e, Germany) and a computer to measure the ion conductivity of the polymer electrolyte membrane. At this time, the frequency range was 1 Hz to 1 MHz, and the potential was 10 Hz.

Properties of Electrolyte Membrane Composed of Cross-linked Water-Soluble Polymer and Di-block Copolymer dBC: PVA: SA thickness ratio Thickness (㎛) Ion Conductivity (S / cm) Swelling in water Tensile Strength (MPa) Example 2 20: 10: 3 132 7.3 × 10 ^-3 26.5% 26.8 Example 3 15: 15: 3 126 6.9 × 10 ^-3 37.9% 41.4 Example 4 10: 20: 3 114 7.1 × 10 ^-3 56.3% 33.5

As shown in Table 1, it can be seen that the ion conductivity is not significantly affected by the content of dBC and PVA. However, as the content of PVA increases, the swelling property increases with water, and the mechanical strength decreases, so that the most stable polymer when the dBC and PVA are included as 50: 50% (dBC: PVA: SA = 15: 15: 3) It can be seen that the electrolyte membrane is formed.

Example 5 Preparation of Cross-linked Electrolyte Membrane Using Water-Soluble Polymer and Tri-Block Copolymer (Polyvinyl Alcohol / Polystyrene-Polyhydroxyethyl Ethyl-Polystyrene Sulfonic Acid Tri-Block Copolymer)

1 g of the tri-block copolymer (tBC) prepared above was dissolved in 30 mL of DMSO, and dissolved by stirring at 25 ° C. for 1 hour.

In addition, 0.5 g of polyvinyl alcohol was separately dissolved in 7.5 mL of DMSO.

When the two solutions were sufficiently dissolved, they were mixed and stirred to prepare a uniform solution. Then, 0.15 mL of sulfosuccinic acid (tBC: PVA: SA = 20: 10: 3 weight ratio) was added to the solution for 30 minutes. Stirred.

The solution was poured into a glass dish, a glass dish was put in a drying oven at 80 ° C. to remove the solvent for two days, and then the remaining solvent was completely removed from the vacuum oven.

Next, the polymer membrane was heat-treated in a drying oven at 120 ° C. to obtain a crosslinked polymer membrane.

The polymer membrane was precipitated in 1 N aqueous sulfuric acid solution for one day to replace sodium cations with hydrogen ions. The polymer membrane was washed 10 times with distilled water to make the solution neutral, and then ion conductivity was measured at 25 ° C. The results are shown in Table 2.

<Example 6>

A polymer electrolyte membrane was prepared in the same manner as in Example 5 except that 1 g of PVA (tBC: PVA: SA = 15: 15: 3 weight ratio) was dissolved in 15 mL of DMSO and then added, and ion conductivity was measured. The results are shown in Table 2.

<Example 7>

A polymer electrolyte membrane was prepared in the same manner as in Example 5 except that 2 g of PVA (tBC: PVA: SA = 10: 20: 3 weight ratio) was dissolved in 15 mL of DMSO, and then ion conductivity was measured. The results are shown in Table 2.

Properties of Electrolyte Membrane Composed of Cross-linked Water-Soluble Polymer and Tri-Block Copolymer dBC: PVA: SA thickness ratio Thickness (㎛) Ion Conductivity (S / cm) Swelling in water Tensile Strength (MPa) Example 5 20: 10: 3 120 4.1 × 10 ^-2 29.3% 24.3 Example 6 15: 15: 3 130 3.2 × 10 ^-2 40.7% 38.7 Example 7 10: 20: 3 118 3.9 × 10 ^-2 61.0% 31.3

As shown in Table 2, it can be seen that the ionic conductivity is not significantly affected by the content of tBC and PVA. However, as the content of PVA increases, the swelling of water increases and the mechanical strength decreases, so that the most stable polymer when tBC and PVA are included as 50: 50% (tBC: PVA: SA = 15: 15: 3) It can be seen that the electrolyte membrane is formed.

1 is a diagram illustrating crosslinking of a hydrogen ion conductive crosslinked polymer electrolyte membrane of the present invention. In Figure 1, A block is a hydrophobic block, B block is a crosslinkable block having a crosslinkable functional group, C block is a hydrophilic block having a sulfonic acid group, D represents a crosslinking agent having a sulfonic acid group.

Claims (15)

Block copolymers comprising a hydrophobic block and a crosslinkable block having a crosslinkable functional group; Water-soluble polymers having a crosslinkable functional group; And Including crosslinkers having sulfonic acid groups, The crosslinkable block polymer of the block copolymer and the water-soluble polymer are crosslinked through the crosslinking agent. The method of claim 1, Cross-linkable block polymer, characterized in that the hydrophobic block comprises a repeating unit represented by the formula (1) or (2): [Formula 1]

[Formula 2]

Where R ₁ represents hydrogen or an alkyl group having 1 to 4 carbon atoms, R ₂ represents a cyano group, an alkyl group having 1 to 4 carbon atoms or an unsubstituted aryl group having 6 to 12 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, or -C (O) -X, X represents an alkoxy group or amino group having 1 to 8 carbon atoms, R ₃ represents hydrogen or an alkyl group having 1 to 4 carbon atoms, n is an integer of 1-4. The method of claim 1, A crosslinkable block polymer, characterized in that the hydrophobic block is contained in 10 to 30 parts by weight based on 100 parts by weight of the total crosslinkable block polymer. The method of claim 1, Crosslinkable block polymer, characterized in that the crosslinkable block comprises a repeating unit represented by the following formula (3): [Formula 3]

Where R ₄ represents hydrogen or an alkyl group having 1 to 4 carbon atoms, R ₅ represents a hydroxy group, an aryl group having 6 to 12 carbon atoms substituted with a hydroxy group, an alkoxy group having 1 to 8 carbon atoms substituted with a hydroxyl group, or -C (O) -X, X represents the C1-C8 alkoxy group substituted by the hydroxy group, or the amino group substituted by the hydroxy group or the C1-C3 alkoxy group here. The method of claim 1, The crosslinkable block polymer is 10 to 30 parts by weight based on 100 parts by weight of the total crosslinkable block polymer. The method of claim 1, A crosslinkable block polymer, characterized in that the block copolymer further comprises a hydrophilic block having sulfonic acid groups. The method of claim 6, A hydrophilic block having a sulfonic acid group is a crosslinkable block polymer, characterized in that it comprises a repeating unit represented by the following formula (4): [Formula 4]

Where R ₆ represents hydrogen or an alkyl group having 1 to 4 carbon atoms, R ₇ is an aryl group having 6 to 12 carbon atoms substituted with a sulfonic acid group, an alkyl group having 1 to 8 carbon atoms substituted with a sulfonic acid group, an alkoxy group having 1 to 8 carbon atoms substituted with a sulfonic acid group, or -C (O) -X Indicates, X represents an alkoxy group having 1 to 8 carbon atoms substituted with a sulfonic acid group. The method of claim 7, wherein A crosslinkable block polymer, characterized in that the hydrophilic block is included in 10 to 30 parts by weight based on 100 parts by weight of the total crosslinkable block polymer. The method of claim 1, The water-soluble polymer is a crosslinkable block polymer, characterized in that it comprises a repeating unit represented by the formula (5): [Formula 5]

Where R ₈ represents hydrogen or an alkyl group having 1 to 4 carbon atoms, R ₉ represents a hydroxy group, an aryl group having 6 to 12 carbon atoms substituted with a hydroxy group, an alkoxy group having 1 to 8 carbon atoms substituted with a hydroxyl group, or -C (O) -X, X represents the C1-C8 alkoxy group substituted by the hydroxy group, or the amino group substituted by the hydroxy group or the C1-C3 alkoxy group here. The method of claim 1, The water-soluble polymer is 40 to 80 parts by weight based on 100 parts by weight of the total crosslinkable block polymer. The method of claim 1, A crosslinkable block polymer characterized in that the crosslinker is a compound of formula 6 or 7: [Formula 6]

[Formula 7]

Where n represents the integer of 1-10. The method of claim 1, A crosslinkable block polymer, wherein the crosslinking agent is included in an amount of 10 to 30 parts by weight based on 100 parts by weight of the total crosslinkable block polymer. Preparing a block copolymer comprising a hydrophobic block and a crosslinkable block having a crosslinkable functional group; And And a second step of crosslinking the water-soluble polymer having a crosslinkable functional group and the crosslinkable block using a crosslinking agent having a sulfonic acid group. A polymer electrolyte membrane comprising the crosslinkable block polymer according to any one of claims 1 to 12. Cathode; Anode; And A fuel cell comprising the electrolyte membrane according to claim 14 located between the cathode and the anode.

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