KR101461417B1 - Perfluorosulfonic acid membrane modified with amine compounds and method for the preparation thereof - Google Patents

Abstract

According to the present invention, an amine compound is crosslinked to a perfluorinated sulfonic acid polymer membrane to provide a cation exchange membrane having reduced methanol permeability and vanadium permeability while maintaining hydrogen ion conductivity. The cation exchange membrane can be used for a direct methanol fuel cell or a redox flow cell The present invention can be applied not only to a brine electrolytic solution device, an electrodialysis device, and the like.

Description

BACKGROUND OF THE INVENTION Field of the Invention [0001] The present invention relates to a perfluorinated sulfonic acid membrane modified with an amine compound and a method for preparing the same.

The present invention relates to a perfluorinated sulfonic acid polymer cation exchange membrane, and more particularly, to a cation exchange membrane crosslinked with an amine compound in a perfluorinated sulfonic acid polymer and a method for producing the same.

Fuel cells as an environmentally friendly alternative energy source have recently been recognized as one of the most noticeable energy sources. These fuel cells are known to be environmentally friendly in that they are not only energy-efficient because the energy of fuel is directly converted into electric energy, but also water and carbon dioxide are produced by-products. BACKGROUND ART [0002] Fuel cells include solid oxide fuel cells, molten carbonate fuel cells, phosphoric acid fuel cells, and polymer electrolyte fuel cells, depending on the type of an electrolyte layer constituting a fuel cell. Among them, Proton Exchange Membrane Fuel Cell (PEMFC) uses Polymer Electrolyte Membrane, which can use hydrogen or methanol as a fuel, and the operating temperature is the lowest among the above fuel cells. So that it can be applied as a portable fuel cell. A DMFC (Direct Methanol Fuel Cell) is a fuel cell that uses methanol as fuel in a PEMFC. When DMFC is injected from the outside, methanol is oxidized by the catalyst in the anode and decomposed into hydrogen ions and electrons , The generated hydrogen ions pass through the polymer electrolyte membrane and the electrons generated at the same time pass through the external circuit and move to the cathode. The electrons thus moved react with hydrogen ions and oxygen to generate electricity by discharging water.

The Redox Flow Battery (Redox Flow battery, RFB) is an electrochemical secondary battery that stores electrical energy as chemical energy through the ion change of the redox pair material dissolved in the electrolyte solution. Among them, the Vanadium Redox Flow Battery (VRB) has advantages such as high open circuit voltage (OCV) and the possibility of using the redox pair material of the same kind at the anode and cathode, Much research is underway compared to batteries. The research on VRB is centered on electrode modification, ion exchange membrane, and large capacity stack manufacturing. Recent active ion exchange membrane researches have shown that V ^{4 +} or V ^{5 +} ions in a cathode electrolyte crossover to a cathode electrolyte or V ^{2 +} or V ^{3 +} ions in a cathode electrolyte are crossover to a cathode electrolyte, The present invention relates to an electrolyte membrane capable of preventing an electrolyte from being contaminated.

The polymer electrolyte, which is generally used as a cation exchange membrane, is mainly made of Nafion manufactured by DuPont, USA, and has a similar structure to a Dow chemical membrane of Dow Chemical Company, Aciplex of Asahi Chemical Co., , Hyflon Ion from Solvay Solexis, and Gore-select from Gore. These are sulfonated perfluorinated polymers that have high proton conductivity and excellent mechanical strength and chemical stability. Because it is very widely used.

However, when such a polymer membrane is used as a methanol fuel cell membrane membrane as it is without a pretreatment reforming process, there is a problem that the generated voltage is lowered due to high permeability of methanol used as a fuel, and even when used for a hydrogen fuel cell, It is known that the performance is lowered when operating at a temperature of 80 캜 or higher. In addition, when the perfluoro polymer is used as a separation membrane of a redox flow cell, the permeability to compounds other than hydrogen ion is high, and the performance of the redox flow cell is deteriorated.

In order to solve this problem, Non-Patent Document 1 below attempts to overcome the disadvantages through compounding Nafion or similar polymers with inorganic compounds and similar methods have been tried. The following non-patent document 2 relates to a composite membrane prepared by crosslinking sulfonated polyether ether ketone (sPEEK) and Nafion, and it is described that the permeability of the electrolyte membrane can be reduced through such crosslinking. However, attempts to complex with such non-fluorine-based compounds or polymers may impair the physical and chemical stability of the membranes. Composition with an inorganic compound is accompanied by deterioration of the mechanical properties such as elongation and tensile strength of the separator, and there is a problem that the oxidation resistance of the hydrocarbon-based polymer is deteriorated by the presence of the hydrocarbon.

H. Zhang and P.K. Shen, Chem. Rev.112, 2780 (2012) Q. Luo et al. J. Mem. Sci. 325, 553 (2008), N. Zhang et al., Int. J. Hydrogen Ener. 36, 11025 (2011)

Accordingly, a problem to be solved by the present invention is to provide a cation exchange membrane in which an amine compound is crosslinked to a perfluoro sulfonic acid polymer, and a method for producing the same.

A second object of the present invention is to provide a polymer electrolyte fuel cell, a redox flow cell and a brine electrolysis tank using the cation exchange membrane.

In order to solve the above problems, the present invention provides a cation exchange membrane crosslinked with an amine compound in a perfluorinated sulfonic acid polymer, wherein the perfluorinated sulfonic acid polymer comprises a step in which a sulfonic acid group is substituted with a sulfonimidazole group by carbonyldiimidazole .

The present invention also provides a method for producing the cation exchange membrane.

The cation exchange membrane of the present invention crosslinks the perfluorinated sulfonic acid polymer to lower the methanol permeability and the vanadium permeability. When the amine compound is used as the crosslinking agent, the hydrogen ion conductivity is maintained or higher than that before crosslinking, and when the cation exchange membrane is used, Fuel cell can be provided.

1 is a schematic view showing a method for producing a cation exchange membrane of the present invention.
2 is a ¹ H-NMR spectrum of SDADPS.
3 is an ATR-FTIR spectrum of a cation exchange membrane crosslinked with SDADPS according to the present invention.
4 is an ATR-FTIR spectrum of a cation exchange membrane crosslinked with DAPSONE according to the present invention.
5 is a UV-Visible spectrum of a cation exchange membrane crosslinked with SDADPS according to the present invention.
6 is a UV-Visible spectrum of a cation exchange membrane crosslinked with DAPSONE according to the present invention.
FIG. 7 is a graph comparing the theoretical IEC and the optimized IEC of the cation exchange membrane according to the crosslinking agent content.
8 is a graph showing a change in water content of the cation exchange membrane according to the present invention.

Hereinafter, the present invention will be described in detail.

The inventors of the present invention have found that the use of carbonyldiimidazole (CDI) to reduce methanol permeability and vanadium permeability, which are disadvantages of Nafion electrolyte membranes excellent in hydrogen ion conductivity and chemical stability, Covalent crosslinking of sulfonamides is introduced between the catalysts of the present invention.

The present invention relates to a cation exchange membrane crosslinked with an amine compound in a perfluorinated sulfonic acid polymer,

The perfluorinated sulfonic acid polymer is substituted with a sulfonimidazole group by the carbonyldiimidazole to accelerate the crosslinking reaction with the amine compound.

The carbonyldiimidazole promotes a crosslinking reaction with an aminic compound by substituting a sulfonic acid group of a perfluorinated sulfonic acid polymer with a sulfonimidazole group by the following Reaction Scheme 1. As the reaction progresses, carbon dioxide is generated, and the reaction proceeds due to the generation of bubbles.

[Reaction Scheme 1]

The amine compound is characterized by containing a sulfonic acid group and represented by the following general formula (1).

[Chemical Formula 1]

H ₂ N-Ar ₁ -NH ₂

Wherein Ar ₁ is a group having a carbon number of 6-24 arylene ring, the aromatic ring is _{SO 3 H, COOH, PO 3} H 2 , or may be substituted or unsubstituted with an alkali metal salt thereof, wherein the aromatic ring is present alone, or ; Two or more are bonded to each other to form a condensed ring; Two or more of them are connected by a single bond, O, S, C (= O), S (= O) ₂ or (CH ₂ ) _n (n is an integer of 1 or 2).

The amine compound is also represented by the following general formula (2).

(2)

H ₂ N-Ar ₂

Wherein Ar ₂ is a 6-24 carbon atoms, an arylene group the aromatic ring, the aromatic ring is _{SO 3 H, COOH, PO 3} H 2 , or may be substituted or unsubstituted with an alkali metal salt thereof, wherein the aromatic ring is present alone, or ; Two or more are bonded to each other to form a condensed ring; Two or more of them are connected by a single bond, O, S, C (= O), S (= O) ₂ or (CH ₂ ) _n (n is an integer of 1 or 2).

The amine compound may be SO ₃ H, COOH, PO ₃ H ₂ Or an H ₂ N- (CH ₂ ) _n -NH ₂ or H ₂ N- (CH ₂ ) _n -H (n is an integer of 2-6) substituted or unsubstituted with an alkali metal salt thereof have.

The content of the amine compound may be 1-30 moles based on perfluorinated sulfonic acid polymer.

According to one embodiment of the present invention, one or more inorganic additives selected from the group consisting of H ₃ PO ₄ , TiO ₂ , Al ₂ O ₃ and inorganic additives represented by the general formula (3) are added to the cation exchange membrane on the cation exchange membrane standard 5 -40 parts by weight may be added.

(3)

H _m (X _x Y _y O _z ) (n H ₂ O)

In Formula 3,

X is any one selected from B, Al, Ga, Ge, Si, Sn, P, As, Sb, Te,

Y is any one selected from the first, second, and third transition elements,

m is an integer of 1-10, and n is an integer of 2-100.

The present invention also provides a method for producing a cation exchange membrane comprising the following steps, and a schematic view thereof is shown in Fig.

Reacting a perfluoro sulfonic acid polymer with carbonyldiimidazole to prepare a perfluorinated sulfonic acid polymer having sulfonic acid groups activated by sulfonimidazole groups;

Reacting the activated perfluorinated sulfonic acid polymer with an amine compound to prepare a crosslinked perfluorinated sulfonic acid polymer; And

Casting the cross-linked perfluoro sulfonic acid polymer on a glass plate and heat-treating the same.

Specifically, as shown in Reaction Scheme 2 below, sulfone groups of Nafion (perfluorinated sulfonic acid) polymer are reacted with carbonyldiimidazole to become sulfonimidazole, thereby promoting the crosslinking reaction with the crosslinking agent. The sulfone group of Nafion participates in the crosslinking reaction and is consumed, but SDADPS, which is a crosslinking agent, contains sulfone group, so that the sulfone group content of Nafion polymer is maintained and hydrogen ion conductivity is not lowered.

[Reaction Scheme 2]

An amphoteric polar solvent such as dimethylacetamide (DMAc), dimethylformamide (DMF) or N-methylpyrrolidone (NMP) may be used instead of the above-mentioned solvent dimethylsulfoxide (DMSO).

According to an embodiment of the present invention, the content of the carbonyldiimidazole may be 10-70 mol parts based on the amount of the perfluorinated sulfonic acid polymer. If the amount is less than the lower limit, crosslinking reaction between the perfluoropolysaccharide polymer and the amine compound is difficult to promote. If the upper limit is exceeded, it is necessary to perform a repeated washing process to remove unreacted carbonyldiimidazole. More preferably 40-60 mol parts.

According to another embodiment of the present invention, the content of the amine compound may be 1-30 moles based on perfluorinated sulfonic acid polymer.

The present invention also provides a polymer electrolyte fuel cell using the cation exchange membrane. Since the cross-linked cation exchange membrane according to the present invention has a low methanol permeability, when it is used in a direct methanol fuel cell, the amount of methanol, which is fuel, is transmitted through the electrolyte to the opposite side is reduced, so that the voltage drop is minimized.

The present invention also provides a vanadium redox flow cell using the cation exchange membrane. Since the crosslinked cation exchange membrane according to the present invention has a low vanadium permeability, when used in a vanadium redox flow cell, the amount of vanadium ions that are fuel is transmitted through the electrolyte to the opposite side is reduced, thereby enhancing energy efficiency.

Hereinafter, the present invention will be described in more detail with reference to preferred embodiments and the like. It will be apparent to those skilled in the art, however, that these examples are provided for further illustrating the present invention and that the scope of the present invention is not limited thereto.

<Examples>

Manufacturing example  One. SDADPS  Produce

SDADPS (3,3'-disulfonated-4,4'-diaminophenoxy-diphenylsulfone) is an example of an amine compound prepared by a method known from the literature (Kim Jungmin et al., Polymer (Korea) 35, 106 (2011)).

After adding 30 g (0.105 mol) of 4,4'-dichlorodiphenylsulfone and fuming sulfuric acid (60 mL, 30% SO ₃ ) into a 500 mL round-bottom flask, Stir at 110 &lt; 0 &gt; C. The reaction was cooled at room temperature, then cold distilled water was added and 60 g of NaCl was salted out to give a white precipitate. The reaction was neutralized with 10 N aqueous NaOH solution and again salted with 60 g NaCl. (IPA, 99.5%, Samchun Pure Chemical Co., Ltd., Korea)) was recycled more than twice with a solvent mixed with 30/70 (v / v) to remove impurities. The recrystallized reactants were filtered and vacuum dried at 120 ° C for 24 hours. The yield was about 60%.

4.913 g (10 mmol) of sulfonated dichlorodiphenyl sulfone obtained from the above reaction was added to 2.401 g (22 mmol) of 3-aminophenol and 1.796 g (13 mmol) of potassium carbonate potassium carbonate, 40 mL of DMSO, and 20 mL of toluene were reacted at 160 ° C for 8 hours in a nitrogen atmosphere through a dean stark trap, and then water and toluene were completely removed and reacted at 170 ° C for 12 hours. NaCl and KCl generated during the reaction were filtered through a filter and the reaction was precipitated in IPA to synthesize sulfonated diaminodiphenyl sulfone. Then, 0.1 M NaOH aqueous solution and sulfonated diaminodiphenyl sulfone (sodium salt form, Mw = 636 g / mol) were stirred and precipitated in IPA. After filtration, the compound was obtained by vacuum drying at 30 ° C. for 24 hours. The yield was about 70% .

Example  One.

A crosslinked perfluorinated cation exchange membrane was prepared using carbonyldiimidazole and diamine, and the content of crosslinking agent is shown in Table 1. The Nafion polymer used in the preparation of the cation exchange membrane was obtained using Nafion dispersion, and the procedure was as follows.

A 100 mL two-necked flask was charged with 1.0 g of a stirrer and Nafion (dried Nafion D2021, 0.92 mmol of sulfonic acid) and dissolved in 8 mL of dimethyl sulfoxide at 60 ° C. After cooling to room temperature, a mixed solution of 0.075 g (0.46 mmol) of carbonyldiimidazole (CDI) and 1.0 mL of dimethyl sulfoxide was slowly added dropwise under a nitrogen stream and stirred for 2 hours to remove the sulfonic acid To obtain a Nafion solution activated by a dazole.

A mixed solution of 0.0176 g (0.0276 mmol) of sodium salt of 3,3'-disulfonated-4,4'-diaminophenoxy-diphenylsulfone (SDADPS) and 1.0 mL of dimethylsulfoxide was slowly added dropwise to the solution and stirred at room temperature for 1 hour A mixture was obtained.

Then, the mixed polymer solution was cast on a horizontal glass plate to prepare a thin film. The thickness of the thin film was adjusted to about 40-80 탆 by using a doctor blade. Thereafter, it was gradually dried at 60 DEG C under a nitrogen stream for 12 hours, and dried and crosslinked at 160 DEG C for 14 hours using a vacuum oven.

The film cast on the glass plate was cooled to room temperature, deionized water was poured out of the glass plate, immersed in a 1.5 M aqueous hydrochloric acid solution for 24 hours to perform cation exchange, and then immersed in deionized water for 12 hours to remove all of the free hydrochloric acid And a cation exchange membrane was prepared. The film thus obtained was dried in a vacuum at room temperature for 3 hours and at 160 ° C for 12 hours.

Example  2 and 3.

A cation exchange membrane was prepared in the same manner as described above except that the content of SDADPS was 0.0644 mmol and 0.138 mmol, respectively.

Example  4.

The procedure of Example 1 was repeated except that 9.0 mg (0.046 mmol) of sulfanilic acid sodium salt (Sulfanil S) was used instead of SDADPS to prepare a cation exchange membrane.

Example  5.

A cation exchange membrane was prepared using 14 mg (0.046 mmol) of 7-amino-1,3-naphthalenedisulfonate monopotassium salt (ANDSP), which was the same as Example 1 but was vacuum-dried instead of SDADPS.

Example  6 to 9.

11.4, 16.0, 34.3 mg (0.0272, 0.046, 0.0644, 0.138 mmol) of DAPSONE (bis (4-aminophenyl) sulfone) was used instead of SDADPS in the same manner as in Example 1 except that the cation exchange membrane was used without a sulfone group. Was used to prepare a cation exchange membrane.

Comparative Example  One.

Nafion 117 was used as a Nafion polymer for comparison with cation exchange membranes prepared from perfluoro sulfonic acid polymers without using crosslinking agents.

And then immersed in a 1.5 M aqueous hydrochloric acid solution for 24 hours, immersed in deionized water for 12 hours, and washed to remove all of the free hydrochloric acid, thereby preparing a cation exchange membrane.

Experimental Example  One. SDADPS  Manufacturing Confirmation

A 300 MHz Unityinova ¹ H-NMR spectrometer (VARIAN, USA) was used to confirm the synthesis of the synthesized SDADPS crosslinking agent. The solvent was CDCl ₃ and DMSO-d ₆ .

As shown in FIG. 2, the proton near the sulfonic acid group appeared singlet at 8.17 ppm, doublet at 7.6 ppm, doublet at 6.8 ppm, proton at amino phenol group doubled at triplet at 7.02 ppm, doublet at 6.36 ppm, singlet at 6.23 ppm , 6.19 ppm doublet, and the amine peak was 5.25 ppm, singlet, and the integral ratio of the other proton to double, indicating that SDADPS was synthesized.

Experimental Example  2. Cation Exchange membrane  Manufacturing Confirmation

(1) ATR-FTIR

To confirm the structure of the crosslinked cation exchange membrane, ATR (Attenuated Total Reflectance) accessory of PIKE Technologies was attached to a MAGNA-IR760 spectrometer.

3 and 4 are ATR-FTIR spectra of Nafion cation exchange membranes crosslinked using SDADPS and DAPSONE according to the examples and comparative examples of the present invention. For FTIR analysis, 1.5 M HCl aqueous solution was treated with acid for one day, washed several times with deionized water, and dried at 80 ° C for 24 hours under reduced pressure.

The intensity of the peak appearing in ether was adjusted to ^1, the same arbitrary scale ^- to 1052 cm 3 is to confirm the content of the crosslinking agent in the film ATR-FTIR spectra crosslinked using SDADPS qualitatively. The peak at 1600 cm ^-1 and 1478 cm ^-1 is an absorption band of an aromatic benzene ring in the crosslinking agent SDADPS and is not present in the spectrum of Nafion but is found in the spectrum of all crosslinked membranes. In addition, it was confirmed that the intensity of aromatic benzene absorption peak increases with increasing crosslinking agent content. The absorption peak at 1509 cm ^-1 is a typical bending vibration peak of a sulfonamide group (-SO ₂ NH) produced by the reaction of a sulfonic acid group with a diamine group. As a result, it was confirmed that the crosslinking reaction was successfully performed and that the crosslinking degree was increased as the crosslinking agent content was increased.

FIG. 4 is an ATR-FTIR spectra of a crosslinked membrane using DAPSONE. Similarly, an absorption peak of an aromatic benzene ring in the crosslinking agent DAPSONE can be confirmed at about 1600 cm ^-1 and 1478 cm ^-1 . However, when DAPSONE was used in which the number of benzene rings in the molecule was smaller than that of SDADPS, the absorption peak of crosslinking agent could not be confirmed when the content of DAPSONE was 10 parts or less.

(2) UV-Visible spectroscopy

The S-4100 UV-Vis spectrophotometer from SCINCO was used to confirm the crosslinking of the cation exchange membrane. SDADPS monomer was used as water and DAPSONE was used as acetonitrile as a solvent. The concentrations were 3.77 × 10 ^-5 M and 4.15 × 10 ^-5 M, respectively.

UV-Visible spectroscopy was used to confirm the crosslinking of membranes with a content of DAPSONE of less than 10 parts. 5 and 6, UV spectra before and after crosslinking can be compared. In FIG. 5, SDADPS is used as a crosslinking agent. It can be seen that the absorption peaks near 296 and 233 nm in SDADPS (sodium salt form) molecules are shifted to 290 and 230 nm in crosslinked cation exchange membranes, respectively. FIG. 6 shows a case where DAPSONE is used as a crosslinking agent. It can be seen that absorption peaks in the vicinity of 293 and 258 nm in the DAPSONE molecules are shifted to 270 and 258 nm in the crosslinked membranes, respectively. It was also confirmed that all of the DAPSONE crosslinking reactions occurred.

Experimental Example  3. Cation Exchange membrane  Absorption and ion exchange capacity ( IEC )

The polymer electrolyte membranes prepared in the above Comparative Examples and Examples were immersed in deionized distilled water for 2 days. After 2 days, the polymer electrolyte membranes were taken out, wiped with tissue paper, and immediately weighed. The water content was calculated from the following equation. Where W _wet represents the weight of the wet state, and W _dry represents the weight of the dried film.

Water content (%) = {(W _wet - W _dry ) / W _dry } x 100

The ion exchange capacity was determined by neutralization titration. A certain amount of dried sample was loaded in a 2 M NaCl solution, stirred for 24 hours, and a phenolphthalein end point was titrated with a 0.025 M NaOH solution. The ion exchange capacity (mmol / g) was calculated from the following equation, where V _NaOH represents the volume of 0.025 M aqueous NaOH solution consumed, V _B represents the volume of NaOH aqueous solution for blank titration and W _dry represents the weight of the dried sample .

IEC = 0.025 x {(V _NaOH - V _B ) / W _dry }

Experimental Example  4. Hydrogen ion conductivity  Measure

The hydrogen ion conductivity was measured by a dipole method and the hydrogen ion conductivity was determined. 4192A LF Impedance Analyzer (Yokogawa, Hewlett Packard) was used and measured at 25 ° C and 80 ° C in deionized water (relative humidity 100%). Hydrogen ion conductivity was obtained from the following equation. σ is the proton conductivity (S / cm), R is the measured impedance, S is the cross-sectional area of the cation exchange membrane (cm ² ), and L is the distance between the electrodes (cm).

σ = L / RS

Experimental Example  5. Methanol permeation experiment

In order to determine the degree of methanol crossover, the cation exchange membrane prepared in the above example was sealed in the middle of a U-shaped chamber connected with distilled water, one side was filled with distilled water and the other side was filled with 2M aqueous methanol solution Next, it was placed in a temperature adjustable water tank. In a chamber with distilled water in both chambers, a constant amount of solution was sampled over time and the concentration of methanol in the chamber was measured. Detailed experimental procedures were performed using known methods (Solid State Ionics 177, 1083 (2006)).

Experimental Example  6. Vanadium product  Permeation experiment

The degree of vanadium oxide permeability was measured using the apparatus used in the methanol permeation experiment. One tube was charged with 1 M MgSO ₄ aqueous solution and 2 M sulfuric acid aqueous solution, the other was filled with 1 M aqueous VOSO ₄ solution and 2 M sulfuric acid aqueous solution, and the two chambers were agitated using a magnetic stirrer. Of the two chambers, VOSO ₄ A constant amount of the solution was taken over time in the opposite chamber with the aqueous solution, and the VO ^{2 +} concentration therein was measured using an ultraviolet / visible light absorber. Detailed experimental procedures were used (Y. Meng et al., J. Power Sources 195, 7701 (2010)).

The type and content of the crosslinking agent used in Examples 1 to 5 and Comparative Examples 1 to 5, and the results of the tests are shown in Table 1.

Types of amines content
(mol parts) IEC
(meq / g) Absorption rate
(%) Hydrogen ion conductivity
(S / cm) Transmittance (25 ° C) 25 ℃ 80 ℃ MeOH ^[1] VO ^{2 + [2]} Example 1 SDADPS 3 0.865 23.7 0.112 0.174 1.62 1.46 Example 2 SDADPS 7 0.855 20.9 0.110 0.192 1.31 1.48 Example 3 SDADPS 15 0.842 18.7 0.109 0.166 0.84 1.51 Example 4 SulfanilS 5 0.857 22.6 0.111 0.180 1.71 2.45 Example 5 ANDSP 5 0.893 24.3 0.116 0.192 1.89 2.74 Example 6 DAPSONE 3 0.908 18.4 0.119 0.160 0.98 0.50 Example  7 DAPSONE 5 0.871 14.9 0.118 0.181 0.943 0.45 Example  8 DAPSONE 7 0.830 13.3 0.118 0.159 0.93 2.52 Example  9 DAPSONE 15 0.747 18.0 0.106 0.170 1.16 1.51 Comparative Example  One ^[3] - - 0.910 17.0 0.091 0.132 2.36 3.56

[1]: x 10 ^-6 cm ² / sec

[2]: x 10 ^-6 cm ² / min

[3]: Nafion 117

Water content and ion exchange capacity (IEC) in cation exchange membranes are very important indicators of hydrogen ion conductivity, mechanical properties and fuel permeability. In FIG. 7, compared with Nafion 117 (0.934 meq / g) before crosslinking, all of the IECs after crosslinking decreased and the crosslinking agent content tended to decrease with increasing crosslinking agent content.

FIG. 8 shows the change in water content according to the degree of crosslinking measured at 25 ° C and 80 ° C. In general, cross-linking reduces the swelling of the membrane due to cross-linking, thereby reducing the water content of the membrane and further decreasing the methanol permeability. In SDADPS membranes, the water content decreased as the degree of crosslinking increased, but the water content was higher than that of Nafion 117 at 25 ℃ and 80 ℃. When DAPSONE was used as a cross - linking agent, the water content decreased as the degree of crosslinking increased from 3 moles to 7 moles, and showed a similar or low water content as compared with Nafion 117.

When the same amount of cross-linking agent is added, the water content of SDADPS shows a relatively high water content in all cases. This indicates that the sulfonic acid group present in the cross-linking agent SDADPS increases the hydrophilicity of the membrane I will. The molecular length of SDADPS is about 2.1 ㎚, which is about two times longer than that of DAPSONE (about 1.2 ㎚ in molecular length). Therefore, it shows relatively less compact structure when crosslinked.

As described above, the cross-linked perfluorinated sulfonic acid polymer of the present invention exhibits excellent hydrogen ion conductivity and low methanol permeability and vanadium permeability as shown in Table 1. Therefore, the polymer electrolyte membrane for direct methanol fuel cell and the redox flow It is expected that the performance as a battery separator is superior to that of Nafion. The ion conductivity at 80 캜 is much better than that of the comparative example at 25 캜. Therefore, the ion conductivity and stability at the higher temperature are expected to be excellent.

Claims (14)

A cation exchange membrane crosslinked with an amine compound in a perfluorinated sulfonic acid polymer,
Wherein the amine compound comprises a sulfonic acid group, and the sulfonic acid group is substituted with a sulfonimidazole group by the carbonyldiimidazole of the perfluorinated sulfonic acid polymer. The method according to claim 1,
Wherein the amine compound is an amine compound represented by the following formula (1).
[Chemical Formula 1]
H ₂ N-Ar ₁ -NH ₂
In Formula 1,
Wherein Ar ₁ is a group having a carbon number of 6-24 arylene ring, the aromatic ring is _{SO 3 H, COOH, PO 3} H 2 , or may be substituted or unsubstituted with an alkali metal salt thereof, wherein the aromatic ring is present alone, or ; Two or more are bonded to each other to form a condensed ring; Two or more of them are connected by a single bond, O, S, C (= O), S (= O) ₂ or (CH ₂ ) _n (n is an integer of 1 or 2). The method according to claim 1,
Wherein the amine compound is an amine compound represented by the following formula (2).
(2)
H ₂ N-Ar ₂
Wherein Ar ₂ is a 6-24 carbon atoms, an arylene group the aromatic ring, the aromatic ring is _{SO 3 H, COOH, PO 3} H 2 , or may be substituted or unsubstituted with an alkali metal salt thereof, wherein the aromatic ring is present alone, or ; Two or more are bonded to each other to form a condensed ring; Two or more of them are connected by a single bond, O, S, C (= O), S (= O) ₂ or (CH ₂ ) _n (n is an integer of 1 or 2). The method according to claim 1,
The amine compound may be H ₂ N- (CH ₂ ) _n -NH ₂ (SO ₃ H, COOH, PO ₃ H ₂ or an alkali metal salt thereof substituted or unsubstituted with an alkali metal salt thereof) Or H ₂ N- (CH ₂ ) _n -H (wherein n is an integer of 2-6). The method according to claim 1,
Wherein the content of the amine compound is 1 to 30 mol parts based on perfluorinated sulfonic acid polymer. The method according to claim 1,
Wherein one or two or more inorganic additives selected from the group consisting of H ₃ PO ₄ , TiO ₂ , Al ₂ O ₃ and an inorganic additive represented by the general formula (3) are added to the cation exchange membrane.
(3)
H _m (X _x Y _y O _z ) (n H ₂ O)
In Formula 3,
X is any one selected from B, Al, Ga, Ge, Si, Sn, P, As, Sb, Te,
Y is any one selected from the first to third transition elements,
m is an integer of 1-10, and n is an integer of 2-100. The method according to claim 6,
Wherein the content of the inorganic additive is 5 to 40 parts by weight based on the weight of the cation exchange membrane. Reacting a perfluoro sulfonic acid polymer with carbonyldiimidazole to prepare a perfluorinated sulfonic acid polymer having sulfonic acid groups activated by sulfonimidazole groups;
Reacting the activated perfluorinated sulfonic acid polymer with an amine compound to prepare a crosslinked perfluorinated sulfonic acid polymer; And
And casting the cross-linked perfluoro sulfonic acid polymer on a glass plate and heat-treating the cross-linked perfluoro sulfonic acid polymer. 9. The method of claim 8,
Wherein the content of the carbonyldiimidazole is 10 to 70 mol% based on the perfluorinated sulfonic acid polymer. 9. The method of claim 8,
Wherein the content of the carbonyldiimidazole is 40 to 60 mol% based on the perfluorinated sulfonic acid polymer. 9. The method of claim 8,
Wherein the content of the amine compound is 1 to 30 mol parts based on perfluorinated sulfonic acid polymer. 11. A polymer electrolyte fuel cell using the cation exchange membrane according to any one of claims 1 to 11. A redox flow cell using the cation exchange membrane according to any one of claims 1 to 11. 12. A brine electrolysis bath using the cation exchange membrane according to any one of claims 1 to 11.

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