WO2022270934A1 - Anion exchange composite membrane, manufacturing method therefor, and alkaline fuel cell comprising same - Google Patents

Abstract

The present invention relates to techniques for manufacturing an anion exchange composite membrane and applying the membrane to alkaline fuel cells, water electrolysis, redox flow batteries, and the like, the membrane comprising: a porous support containing polyphenylenesulfide; and an anion exchange layer prepared from a composition, which is filled in the support and contains an anion exchange polymer. The anion exchange composite membrane comprising the porous support according to the present invention has significantly improved mechanical properties, dimensional stability, durability, chemical stability, and long-term stability.

Description

Anion exchange composite membrane, manufacturing method thereof, and alkaline fuel cell including the same

The present invention relates to an anion exchange composite membrane, a manufacturing method thereof, and an alkaline fuel cell including the same, and more particularly, to a porous support comprising polyphenylene sulfide; and an anion conductive polymer formed on the support. The present invention relates to a technique for preparing an anion exchange composite membrane comprising an anion exchange composite membrane and applying the membrane to an alkaline fuel cell, water electrolysis, or redox flow battery.

Until now, polymer electrolyte membrane fuel cells (PEMFC) have been studied a lot because of their advantages of relatively high current density and eco-friendliness. In particular, a perfluorocarbon-based proton exchange membrane represented by Nafion has been mainly used as a polymer electrolyte membrane. However, while the Nafion membrane has excellent chemical stability and high ionic conductivity, it is very expensive and has a low glass transition temperature, so researches that can replace Nafion, including the development of aromatic hydrocarbon-based polymer electrolyte membranes, are being actively conducted.

Among these studies, an alkaline membrane fuel cell (AMFC) using an anion exchange membrane operated in an alkaline environment has recently received attention. In particular, alkaline membrane fuel cells can use inexpensive non-noble metals such as nickel and manganese as electrode catalysts instead of platinum, and are known to have superior performance and price competitiveness compared to polymer electrolyte membrane fuel cells, and continuous research is being conducted. The situation is.

Polymers having aryl ether main chains such as polyaryl ether sulfone, polyphenyl ether, and polyether ether ketone have been mainly used as anion exchange membranes for use in alkaline membrane fuel cells. In addition, crosslinked anion exchange membranes using hydrophobic crosslinking agents such as 1,5-dibromopentane, 1,6-dibromohexane, and 1,6-hexanediamine are known, but hydrophobic anion exchange membranes are used in anion exchange fuel cells. There are problems such as low ionic conductivity, limited flexibility, and low solubility in application. In addition, conventional anion exchange membranes have limited chemical stability (less than 500 hours in 1M NaOH solution at 80 °C) and mechanical properties (less than 30 Mpa tensile strength), so when applied to fuel cells, the power density (0.1 ~ 0.5 Wcm-2) is low and the battery The downside is poor durability.

In addition, conventional anion exchange membranes have poor dimensional stability due to high water uptake and swelling ratio, and it is known that the decrease in physical properties is caused by the fact that most of the anion exchange membranes are formed in the form of a single membrane.

Therefore, the inventors of the present invention, as a result of repeated research to expand the application field of aromatic polymer ion exchange membranes with excellent thermal and chemical stability and mechanical properties, developed polyphenylene anion exchange membranes obtained from polymers introduced with a high content of anion exchange groups. When it is formed on a porous support formed of a sulfide polymer and manufactured in the form of a composite membrane, mechanical properties, dimensional stability, durability, chemical stability, and long-term stability can be greatly improved, and commercialization can be expected, and the present invention has been reached.

[Prior art literature]

[Patent Literature]

Patent Document 1. Korean Patent Registration No. 10-1545229

The present invention was made in view of the above problems, and a first object of the present invention is to provide an anion exchange composite membrane with significantly improved mechanical properties, dimensional stability, durability, chemical stability and long-term stability, and a method for manufacturing the same. will be.

A second object of the present invention is to apply the anion exchange composite membrane to alkaline fuel cells, water electrolysis, and redox flow batteries.

The present invention for achieving the above object is a porous support comprising polyphenylene sulfide (PPS); and an anion exchange layer prepared from a composition containing an anion exchange polymer filled in the porous support and having a repeating unit represented by any one selected from the following <Formula 1> to <Formula 3>. provide a barrier

<Formula 1>

<Formula 2>

<Formula 3>

(In Formulas 1 to 3, A is any one selected from compounds represented by the following structural formulas,

,

,

,

Where x, n, o, p, q, and r are mole fractions in the repeating unit, respectively, x, n, o, p, q, and r are all greater than 0, o + p + q + r = 1, and y Is an integer selected from 1 to 6)

The composition may further include a crosslinking agent, preferably the crosslinking agent is N,N,N',N'-tetramethylmethylenediamine (TMMDA), N,N,N',N'-tetramethylethylenediamine (TMEDA), N,N,N',N'-tetramethyl 1,3-propanediamine (TMPDA), N,N,N',N'-tetramethyl-1,4-butanediamine (TMBDA) , N,N,N',N'-tetramethyl 1-1,6-hexanediamine (TMHDA) and N,N,N',N'-tetraethyl-1,3-propanediamine (TEPDA) It is characterized in that at least one selected from the group consisting of.

The polyphenylene sulfide is characterized in that it is a cross-linked or linear polyphenylene sulfide having a weight average molecular weight of 10000 or more and a degree of dispersion obtained by dividing the weight average molecular weight by the number average molecular weight of 2.5 or less.

The polyphenylene sulfide has a stiffness of 3 to 4 GPa, a strength at break of 50 to 80 MPa, and a yield strength of 50 to 80 MPa.

In Formulas 1 to 3, x = 0.7 to 0.9, n = 0.7 to 0.9, o + p + q + r = 1, o = 0.7 to 0.9, p + q + r = 0.1 to 0.3. .

In addition, the present invention comprises the steps of (I) preparing a porous support by dissolving polyphenylene sulfide (PPS) in a first solvent, casting and drying on a substrate; (II) dissolving an anion exchange polymer having a repeating unit represented by any one selected from the following <Formula 1> to <Formula 3> in a second solvent to obtain a polymer solution; and (III) impregnating and drying the porous support in the polymer solution.

<Formula 1>

<Formula 2>

<Formula 3>

(In Formulas 1 to 3, A is any one selected from compounds represented by the following structural formulas,

,

,

,

Where x, n, o, p, q, and r are mole fractions in the repeating unit, respectively, x, n, o, p, q, and r are all greater than 0, o + p + q + r = 1, and y Is an integer selected from 1 to 6)

The polymer solution may further include a crosslinking agent, and the crosslinking agent is N,N,N',N'-tetramethylmethylenediamine (TMMDA), N,N,N',N'-tetramethylethylenediamine ( TMEDA), N,N,N',N'-tetramethyl 1,3-propanediamine (TMPDA), N,N,N',N'-tetramethyl-1,4-butanediamine (TMBDA), Consisting of N,N,N',N'-tetramethyl 1-1,6-hexanediamine (TMHDA) and N,N,N',N'-tetraethyl-1,3-propanediamine (TEPDA) It is characterized in that at least one selected from the group.

The first solvent and the second solvent are the same as or different from each other, and each independently N-methyl-2-pyrrolidone, dimethyl sulfoxide, dimethylformamide, diethylformamide, dimethylacetamide, tetrahydrofuran, methanol , characterized in that at least one selected from the group consisting of ethanol and ether.

The concentration of the polymer solution is characterized in that 2 to 5% by weight.

In the step (I), the porous support is subjected to carding, garneting, air-laying, wet-laying, melt blowing, spun bonding ( It is characterized in that it is manufactured by any one method selected from the group consisting of spunbonding and stitch bonding.

The drying in step (III) is characterized in that the second solvent is completely removed by first drying in an oven at 80 to 90 ° C for 1 to 10 hours and then drying in a vacuum oven at 110 to 150 ° C for 20 to 30 hours. do.

In addition, the present invention provides an alkaline fuel cell including the anion exchange composite membrane.

In addition, the present invention provides a water electrolysis device including the anion exchange composite membrane.

In addition, the present invention provides a redox flow battery including the anion exchange composite membrane.

Hereinafter, an anion exchange composite membrane and a manufacturing method thereof according to the present invention will be described in detail.

In the present invention, a porous support containing polyphenylene sulfide (PPS); and an anion exchange layer prepared from a composition containing an anion exchange polymer filled in the porous support and having a repeating unit represented by any one selected from the following <Formula 1> to <Formula 3>. provide a barrier

Conventional anion exchange membranes use polyethylene, polypropylene, polytetrafluoroethylene, polyvinylidene fluoride, polyhexafluoropropylene, and polyperfluoroalkylvinyl ether as porous supports, but the porous supports have a degree of substitution of 70% or more. In the case of using an anion exchange polymer into which a high content of anion exchange group is introduced, mechanical properties and chemical durability are rather weakened, resulting in easy breakage. Therefore, by using polyphenylene sulfide (PPS) as the porous support, the anion exchange polymer introduced with a high content of anion exchange groups having a degree of substitution of 70% or more is stably impregnated on the porous support to form a defect-free anion exchange composite membrane. it was completed

The polyphenylene sulfide (PPS) originally has excellent chemical resistance and excellent heat resistance, and has been utilized in various fields. However, the mechanical properties are not sufficient, especially the impact strength is relatively low, and the tensile strength is 6 MPa, so there is a limit as a support. In order to improve the mechanical properties of polyphenylene sulfide, a technique for adding fillers such as glass fibers has been developed, but there is a problem of phase instability such as peeling during secondary processing or post-processing.

However, in the present invention, even without adding a filler to polyphenylene sulfide, a significant effect of improving not only mechanical properties but also chemical properties and transparency is obtained by impregnating an anion exchange polymer into which an anion exchange group having a high degree of substitution of 70% or more is introduced. was able to achieve

In the present invention, the polyphenylene sulfide may be a cross-linked or linear polyphenylene sulfide having a weight average molecular weight of 10000 or more and a degree of dispersion obtained by dividing the weight average molecular weight by the number average molecular weight of 2.5 or less.

The polyphenylene sulfide may have a stiffness of 3 to 4 GPa, a strength at break of 50 to 80 MPa, and a strength at yield of 50 to 80 MPa.

The polyphenylene sulfide may be represented by Formula A below.

[Formula A]

(In the above formula A, Z is an integer from 200 to 2000)

The porous support may be in the form of a nonwoven fabric in which a porous web is formed by crossing polyphenylene sulfide nanofibers or in the form of a porous membrane including a plurality of pores. In particular, a non-woven fabric having a large pore structure inside to improve the anion exchange polymer impregnation rate is preferred.

The thickness of the porous support is not particularly limited, but is preferably in the range of 1 to 100 μm, more preferably in the range of 5 to 50 μm, and more preferably in the range of 10 to 20 μm. When the thickness is less than 1 μm, it is difficult to achieve the desired effect, and when the thickness exceeds 100 μm, it may act as a resistance layer.

The porosity of the porous support is not particularly limited, but may be in the range of 30 to 90%. That is, when the porosity of the porous support is less than 30%, it is difficult to coat the anion exchange polymer, and at the same time, the amount of the anion exchange polymer is small, and the ionic conductivity may be reduced. Not only cannot maintain mechanical strength, but also may be damaged when coating an anion exchange polymer, which may cause difficulties in manufacturing. The porosity of the porous support is most preferably 80% because impregnation is best achieved.

The porous support may be prepared using electrospinning.

In the present specification, 'a composition containing an anion exchange polymer' refers to a composition that is filled on a porous support to form an anion exchange layer, which will be described later.

The anion exchange polymer may have a repeating unit represented by any one selected from the following <Formula 1> to <Formula 3>.

<Formula 1>

<Formula 2>

<Formula 3>

(In Formulas 1 to 3, A is any one selected from compounds represented by the following structural formulas,

,

,

,

Where x, n, o, p, q, and r are mole fractions in the repeating unit, respectively, x, n, o, p, q, and r are all greater than 0, o + p + q + r = 1, and y Is an integer selected from 1 to 6)

In particular, in the above-described anion exchange polymer, in Chemical Formulas 1 to 3, it is more preferable that the mole fraction of the repeating unit into which the anion exchange group is introduced is 0.70 to 0.90. Specifically, in Chemical Formula 1, the x is selected from 0.70 to 0.90. In Formula 2, y is one selected from 0.70 to 0.90, and in Formula 3, o + p + q + r = 1 and o is one selected from 0.70 to 0.90, and p + q + r is When an anion exchange polymer selected from 0.1 to 0.3 is used, high ion exchange capacity can be secured because there is a high content of cationic groups responsible for ion transfer.

In addition, since chemical and mechanical stability can be further improved by using polyphenylene sulfide as a porous support even though a high content of cationic groups is introduced, chemical durability under basic conditions can be improved.

As described above, polyphenylene sulfide has high chemical durability, but poor mechanical properties. However, when the anion exchange polymer of Formulas 1 to 3 with a high content of cationic groups is introduced, the ion exchange capacity is improved to improve the ionic conductivity, chemical durability is also improved, and mechanical properties can be improved by more than two times. there is.

In general, if the ratio of repeating units into which cationic groups are introduced increases and the ratio of relatively stable repeating units decreases, even if a porous support is introduced, chemical stability decreases and is easily decomposed, so both ionic conductivity and mechanical properties are reduced. However, the present invention not only improves ionic conductivity and chemical durability at the same time by introducing anion exchange polymers of Chemical Formulas 1 to 3 into which a high content of cationic groups is introduced onto a porous support of polyphenylene sulfide having poor mechanical properties. The effect of improving mechanical properties by more than two times was achieved.

The composition may further include a crosslinking agent. The crosslinking agent serves to improve the physical/chemical stability and durability of the anion exchange polymer.

The crosslinking agent is N,N,N',N'-tetramethylmethylenediamine (TMMDA), N,N,N',N'-tetramethylethylenediamine (TMEDA), N,N,N',N' -Tetramethyl 1,3-propanediamine (TMPDA), N,N,N',N'-tetramethyl-1,4-butanediamine (TMBDA), N,N,N',N'-tetramethyl It may be at least one selected from the group consisting of 1-1,6-hexanediamine (TMHDA) and N,N,N',N'-tetraethyl-1,3-propanediamine (TEPDA). The crosslinking agent may be used alone or in combination of two or more.

The content of the crosslinking agent may be appropriately selected depending on the structure of the anion exchange polymer and the desired performance of the ion exchange layer. The crosslinking agent may be included in an amount of less than 10% by weight based on the total weight of the composition. When the crosslinking agent is used within the above range, physical/chemical stability and durability of the anion exchange layer may be further improved.

The composition may further include a solvent. The solvent may be at least one selected from the group consisting of N-methyl-2-pyrrolidone, dimethyl sulfoxide, dimethylformamide, diethylformamide, dimethylacetamide, tetrahydrofuran, methanol, ethanol, and ether. .

The amount of the solvent may be greater than 0% by weight and less than or equal to 99% by weight based on the total weight of the composition. When the content of the solvent is within the above range, when the composition for forming an ion exchange membrane is polymerized, the drying time can be shortened and uniform membrane properties can be obtained.

In addition, the present invention (I) preparing a porous support containing polyphenylene sulfide (PPS); (II) dissolving an anion exchange polymer having a repeating unit represented by any one selected from the following <Formula 1> to <Formula 3> in a second solvent to obtain a polymer solution; and (III) impregnating and drying the porous support in the polymer solution.

First, (I) prepare a porous support containing polyphenylene sulfide (PPS). The porous support may be in the form of a nonwoven fabric in which a porous web is formed by crossing polyphenylene sulfide nanofibers or in the form of a porous membrane including a plurality of pores. In particular, a porous membrane having a plurality of large pore structures present therein to improve an anion exchange polymer impregnation rate is preferred.

In the step (I), when the porous support is made in the form of a nonwoven fabric, carding, garneting, air-laying, wet-laying, melt blowing ( It may be manufactured by any one method selected from the group consisting of melt blowing, spunbonding, and stitch bonding.

In the step (I), when the porous support is prepared in the form of a film, the composition containing polyphenylene sulfide is injected into an extruder, discharged through a T-die, molded into a sheet form, and then stretched to form a film. may be manufactured.

The stretching may be performed by a known method such as uniaxial stretching or biaxial stretching (sequential or simultaneous biaxial stretching). In the case of sequential biaxial stretching, the stretching magnification may be 4 to 20 times in the transverse direction (MD) and the longitudinal direction (TD), respectively, and the plane magnification accordingly may be 16 to 400 times.

The thickness of the porous support is not particularly limited, but is preferably in the range of 1 to 100 μm, and more preferably in the range of 5 to 50 μm. More preferably, it may be 10 to 20 μm. When the thickness is less than 1 μm, it is difficult to achieve the desired effect, and when the thickness exceeds 100 μm, it may act as a resistance layer.

The porosity of the porous support is not particularly limited, but may be in the range of 30 to 90%. That is, when the porosity of the porous support is less than 30%, it is difficult to coat the anion exchange polymer, and at the same time, the amount of the anion exchange polymer is small, and the ionic conductivity may be reduced. Not only cannot maintain mechanical strength, but also may be damaged when coating an anion exchange polymer, which may cause difficulties in manufacturing. The porosity of the porous support is most preferably 80% because impregnation is best achieved.

Next, (II) an anion exchange polymer having a repeating unit represented by any one selected from <Formula 1> to <Formula 3> is dissolved in a second solvent to obtain a polymer solution.

<Formula 1>

<Formula 2>

<Formula 3>

(In Formulas 1 to 3, A is any one selected from compounds represented by the following structural formulas,

,

,

,

Where x, n, o, p, q, and r are mole fractions in the repeating unit, respectively, x, n, o, p, q, and r are all greater than 0, o + p + q + r = 1, and y Is an integer selected from 1 to 6)

In particular, in the above-described anion exchange polymer, in Chemical Formulas 1 to 3, it is more preferable that the mole fraction of the repeating unit into which the anion exchange group is introduced is 0.70 to 0.90. Specifically, in Chemical Formula 1, the x is selected from 0.70 to 0.90. In Formula 2, y is one selected from 0.70 to 0.90, and in Formula 3, o + p + q + r = 1 and o is one selected from 0.70 to 0.90, and p + q + r is When an anion exchange polymer selected from 0.1 to 0.3 is used, high ion exchange capacity can be secured because there is a high content of cationic groups responsible for ion transfer.

The first solvent and the second solvent are the same as or different from each other, and each independently N-methyl-2-pyrrolidone, dimethyl sulfoxide, dimethylformamide, diethylformamide, dimethylacetamide, tetrahydrofuran, methanol , It may be any one or more selected from the group consisting of ethanol and ether, but is not limited thereto.

In the step (II), the concentration of the polymer solution may be 2 to 5% by weight, specifically, the polymer solution contains 2 to 5% by weight, specifically 3 to 4% by weight of the anion exchange polymer based on the total weight. %, more specifically 3% by weight.

The polymer solution may further include a crosslinking agent, and the crosslinking agent is N,N,N',N'-tetramethylmethylenediamine (TMMDA), N,N,N',N'-tetramethylethylenediamine ( TMEDA), N,N,N',N'-tetramethyl 1,3-propanediamine (TMPDA), N,N,N',N'-tetramethyl-1,4-butanediamine (TMBDA), Consisting of N,N,N',N'-tetramethyl 1-1,6-hexanediamine (TMHDA) and N,N,N',N'-tetraethyl-1,3-propanediamine (TEPDA) It may be any one or more selected from the group.

The drying in step (III) may be to completely remove the second solvent by first drying in an oven at 80 to 90 ° C for 1 to 10 hours and then drying in a vacuum oven at 110 to 150 ° C for 20 to 30 hours. .

In addition, the impregnation time may be specifically 1 to 50 hours, more specifically 10 to 30 hours, and more specifically 22 to 26 hours, and the drying time after the impregnation is as described above.

In the production method according to the present invention, the reaction temperature and time range of each step may be appropriately adjusted as necessary, and are not particularly limited thereto, but when each reaction is performed under conditions less than the above temperature and time ranges, anion The performance of the exchange composite membrane may deteriorate, and if the exchange membrane is performed under conditions of temperature and time exceeding the above ranges, a cost increase problem may occur due to a decrease in process efficiency due to a long reaction, so it is preferable to perform the exchange membrane within each condition range.

The anion exchange polymer is most preferably an anion exchange polymer represented by Chemical Formula 4 below.

<Formula 4>

(A and x in <Formula 4> are as defined in <Formula 1>)

The anion exchange polymer represented by Chemical Formula 4 is not particularly limited, but examples include (1) poly(2,6-dimethyl-1,4-phenylene oxide), AlCl ₃ and azobisisobutyronitrile (AIBN). The mixture was mixed at a ratio of 1:1 and mixed at a molar ratio of 1:0.7 (specifically, 0.7 equivalents of AlCl3 and AIBN were mixed with respect to 1 equivalent of poly(2,6-dimethyl-1,4-phenylene oxide)) . Specifically, reacting for 1 to 24 hours, more specifically for 1 to 12 hours, and more specifically for 5 to 8 hours to produce PPO (Ac-PPO) represented by <Chemical Formula 4>; may have been

The anion exchange composite membrane according to the present invention can be used as an electrolyte membrane. The electrolyte membrane may be used for an electrolyte membrane for a fuel cell, an electrolyte membrane for a water electrolysis device, and an electrolyte membrane for a redox flow battery.

A fuel cell containing the anion exchange composite membrane according to the present invention may be a solid alkaline fuel cell (SAFC) or a direct borohydride fuel cell (DBFC).

In the above, the solid alkali fuel cell (SAFC) contains an anion exchange composite membrane, supplies one or more fuels selected from the hydrogen-containing gas group of hydrogen, reformed gas, and mixed hydrogen gas to the anode, and supplies oxygen, air, and mixed oxygen gas to the fuel electrode. A fuel cell in which at least one oxidizing agent selected from the group of oxygen-containing gases is supplied to the cathode.

In the above, the direct borohydride fuel cell (DBFC) contains an anion exchange composite membrane, and uses 1 to 20 wt% of sodium borohydride (NaBH4) containing a caustic soda solution in a concentration range of 0 to 5M as fuel to obtain an anode and supplying at least one oxidizing agent selected from the group of oxygen-containing gases such as oxygen, air, and mixed oxygen gas to the cathode.

In the above, the water electrolysis system may be an alkaline water electrolyzer (AWE) using an aqueous KOH solution as an electrolyte, the alkaline water electrolysis system contains an anion exchange composite membrane, and hydroxide ions (OH-) move It is a device that produces hydrogen and oxygen from water.

In the above, the redox flow battery contains an anion exchange composite membrane, and the anion exchange composite membrane is applied to a separator separating both electrodes. The separator prevents mixing of electroactive species in a redox flow battery, passes only a common counter ion transporter at both electrodes, and requires excellent physical strength that is not destroyed by the pressure difference generated between the anode and cathode. , the anion exchange composite membrane of the present invention can be easily applied.

According to the present invention, the mechanical properties, dimensional stability, durability, chemical stability and long-term stability of the anion exchange composite membrane including polyphenylene sulfide (PPS) as a porous support are remarkably improved.

In addition, the anion exchange composite membrane comprising the porous support of the present invention can be applied to alkaline fuel cells, water electrolyzers, redox flow batteries, and the like.

1 is a photograph of an anion exchange membrane prepared from Comparative Example 1 of the present invention.

2 is a photograph of a porous support of polyphenylene sulfide prepared from Preparation Example 2 of the present invention.

3 is a photograph of the anion exchange composite membrane prepared in Example 1 of the present invention.

Figure 4 measures the tensile strength of the anion exchange composite membrane (XAc-PPO-PPS) prepared from Example 1, the anion exchange membrane (XAc-PPO) prepared from Comparative Example 1, and the Ac-PPO single membrane prepared from Preparation Example 1 This is the graph shown by

5 is a graph showing the measured hydroxide ion conductivity over time at 80 ° C. of the anion exchange membrane (XAc-PPO-PPS) prepared from Example 1 and the anion exchange membrane (XAc-PPO) prepared from Comparative Example 1 it's a graph

FIG. 6 is a graph showing the measured hydroxide ion conductivity over time at 80° C. of the anion exchange composite membrane (XAc-PPO+PE) prepared in Comparative Example 2. FIG.

Hereinafter, an embodiment for manufacturing an anion exchange composite membrane according to the present invention will be described in detail with accompanying drawings.

Preparation Example 1. Synthesis of quaternary ammoniumized polyphenylene oxide copolymer (Ac-PPO)

Poly(2,6-dimethyl-1,4-phenylene oxide) was dissolved in 1,2-dichloroethane solvent (PPO solution). AlCl ₃ and azobisisobutyronitrile (AIBN) were mixed in a weight ratio of 1:1 to prepare a mixed solution added to 1,2-dichloroethane solvent. The PPO solution and the mixture were mixed at a molar ratio of 1:0.7 (specifically, 0.7 equivalents of AlCl3 and AIBN were mixed with respect to 1 equivalent of poly(2,6-dimethyl-1,4-phenylene oxide)). It was reacted for 6 hours. Methanol (MeOH) was added thereto to precipitate, washed several times with methanol, and dried in a vacuum oven to remove the solvent, thereby obtaining a polyphenylene oxide copolymer represented by Formula 4>.

<Formula 4>

(In the above <Formula 4>, x is the mole fraction in the repeating unit, x = 0.7, and A is

to be)

The synthesis of the polyphenylene oxide copolymer represented by <Chemical Formula 4> from Preparation Example 1 was confirmed by ¹ H-NMR and FT-IR data as follows. ¹ H-NMR (300 MHz, DMSO-d ₆ , ppm): 13.50 (s, -COOH), 10.41 (s, -OH), 8.10 (d, H _ar , J=8.0 Hz), 7.92 (d, H _ar , J=8.0 Hz), 7.85 (s, H _ar ), 7.80 (s, H _ar ), 7.71 (s, H _ar ), 7.47 (s, H _ar ), 7.20 (d, H _ar , J=8.3 Hz), 7.04 (d, H _ar , J=8.3 Hz). FT-IR (film): ν(OH) at 3400 cm ^-1 , ν(C=O) at 1786 and 1716 cm ^-1 , Ar (CC) at 1619, 1519 cm ^-1 , imide ν(CN) at 1377 cm ^-1 , (CF) at 1299-1135 cm ^-1 , imide (CNC) at 1102 and 720 cm ^-1 .

Preparation Example 2. Preparation of polyphenylene sulfide porous support

A paste was prepared by uniformly dispersing 23 parts by weight of liquid lubricant naphtha by mixing and stirring with respect to 100 parts by weight of PPS fine powder having an average particle diameter of 570 μm. Next, the paste was aged at 50° C. for 18 hours, and then compressed using a molding jig to prepare a PPS block. Next, after putting the PPS block into an extrusion mold, pressure extrusion was performed under a pressure of about 0.10 Ton/cm ² .

Next, it was rolled using a pressure roll to prepare an unsintered tape having an average thickness of 850 μm. Next, the unsintered tape was dried by applying heat of 180° C. while being transferred to a conveyor belt at a speed of 3 M/min to remove the lubricant. The unsintered tape from which the lubricant was removed was uniaxially stretched (longitudinal stretching) by 6.5 times at a stretching temperature of 280° C. and a stretching speed of 10 M/min. The uniaxially stretched unsintered tape was biaxially stretched (width direction stretched) 30 times under conditions of a stretching temperature of 250° C. and a stretching speed of 10 M/min to prepare a porous support.

Next, a PPS porous support having an average thickness of 14 μm and an average pore size of 0.114 μm was prepared by firing the uniaxially and biaxially stretched porous support on a conveyor belt by applying a temperature of 420 ° C. at a speed of 15 M / min.

Example 1. Preparation of anion exchange composite membrane (xAc-PPO-PPS)

Prepare polyphenylene sulfide, which is a porous support prepared in Preparation Example 2.

A first solution was prepared by mixing 15% by weight of the polyphenylene oxide copolymer represented by <Chemical Formula 4> prepared in Preparation Example 1 and 85% by weight of an NMP solvent. A polymer solution was prepared by mixing N,N,N',N'-tetramethyl-1,6-hexadiamine (TMHDA) with the first solution. The TMHDA crosslinking agent was mixed with the polyphenylene oxide copolymer (Formula 4) in an equivalent ratio of 1:1 to achieve 100% crosslinking.

Next, the porous support was impregnated with the polymer solution, taken out, put into a vacuum oven, and dried with hot air at 80° C. for 8 hours. Thereafter, the mixture was heated in a vacuum oven at 120° C. for 24 hours to prepare an anion exchange composite membrane in the form of a composite membrane formed with a cross-linked polyphenylene oxide copolymer (XAc-PPO) of <Chemical Formula 4>.

Comparative Example 1. Preparation of an anion exchange membrane in the form of a single membrane

A first solution was prepared by mixing 15% by weight of the polyphenylene oxide copolymer represented by <Chemical Formula 4> prepared in Preparation Example 1 and 85% by weight of an NMP solvent. A polymer solution was prepared by mixing N,N,N',N'-tetramethyl-1,6-hexadiamine (TMHDA) with the first solution. The TMHDA crosslinking agent was mixed with the polyphenylene oxide copolymer (Formula 4) in an equivalent ratio of 1:1 to achieve 100% crosslinking.

A film was formed with only the polymer solution and dried under vacuum at 60° C. for 12 hours to prepare a single-membrane anion exchange membrane.

Comparative Example 2. Preparation of Anion Exchange Composite Membrane Using Polyethylene Support

In Example 1, an anion exchange composite membrane was prepared in the same manner as in Example 1, except that polyethylene was used as a support instead of polyphenylene sulfide, which is a porous support prepared in Preparation Example 2.

The polyethylene used in the present invention was purchased from W.Scope Korea and had a porosity of 80%.

Figure 1 is a photograph of an anion exchange membrane prepared from Comparative Example 1 of the present invention, Figure 2 is a photograph of a porous support of polyphenylene sulfide prepared from Preparation Example 2 of the present invention, Figure 3 is a photograph of the present invention This is a photograph of the anion exchange composite membrane prepared from Example 1 of

As shown in FIG. 1, it was confirmed that the anion exchange polymer (Preparation Example 1) into which the anion exchange group was introduced with a high substitution degree of 70% or more could not be prepared in the form of a single membrane because it had weak mechanical and chemical properties and was easily broken. .

As shown in FIG. 2, it was confirmed that polyphenylene sulfide (PPS) forms a porous support.

As shown in FIG. 3, in the case of the anion-exchange composite membrane prepared in Example 1, mechanical properties and durability were improved, and it could be seen that a defect-free anion-exchange composite membrane was manufactured in a good state. In addition, it can be seen that the opacity of the porous support was improved.

Figure 4 measures the tensile strength of the anion exchange composite membrane (XAc-PPO-PPS) prepared from Example 1, the anion exchange membrane (XAc-PPO) prepared from Comparative Example 1, and the Ac-PPO single membrane prepared from Preparation Example 1 This is the graph shown by

As shown in FIG. 4, the anion exchange composite membrane prepared from Example 1 exhibited tensile strength more than twice as high as that of the anion exchange membrane (XAc-PPO) prepared from Comparative Example 1, indicating that mechanical properties were improved. .

On the other hand, when Ac-PPO prepared from Preparation Example 1 is prepared as an anion exchange membrane alone in the form of a single membrane like XAc-PPO of Comparative Example 1, the shape of the prepared anion exchange membrane is not constant and is easily damaged, so that sufficient It can be confirmed that no mechanical strength can be obtained. That is, it can be seen that the AC-PPO of Preparation Example 1 alone cannot be used as an anion exchange membrane, and even if it is crosslinked (XAx-PPO: Comparative Example 1), sufficient mechanical strength cannot be obtained.

5 is a graph showing the measured hydroxide ion conductivity over time at 80 ° C. of the anion exchange membrane (XAc-PPO-PPS) prepared from Example 1 and the anion exchange membrane (XAc-PPO) prepared from Comparative Example 1 FIG. 6 is a graph showing the measured hydroxide ion conductivity over time at 80° C. of the anion exchange composite membrane (XAc-PPO+PE) prepared in Comparative Example 2.

Alkali stability was measured by recording the hydroxide ion conductivity as a function of time under the conditions of a 1 M KOH solution at 80 °C. The change in hydroxide ion conductivity compared to the initial (0 hour) hydroxide ion conductivity was calculated and shown.

As shown in FIG. 5, it can be seen that the hydroxide ion conductivity of the anion exchange membrane (XAc-PPO) of Comparative Example 1 starts to decrease by 10% before 200 hours and decreases by more than 50% at 1000 hours.

On the other hand, it can be confirmed that the anion exchange composite membrane prepared in Example 1 maintains 100% hydroxide ion conductivity for more than 2500 hours.

As shown in FIG. 6, it can be confirmed that the anion exchange composite membrane of Comparative Example 2, like the anion exchange membrane of Comparative Example 1, started to decrease at 100 hours, decreased by 10% or more at 200 hours, and decreased by 30% or more at 900 hours. there is. That is, it can be seen that when using a porous support other than polyphenylene sulfide, the alkali stability is greatly reduced even when XAc-PPO is used as an anion exchange layer.

As described above, the anion exchange composite membrane using polyphenylene sulfide as a porous support and impregnating quaternary ammoniumized polyphenylene oxide into which a high content of anion exchange groups is introduced on the porous support has ionic groups and a polymer backbone. It showed excellent application stability at high temperature without decomposition, showed high tensile strength of 40 MPa, and maintained 100% of the initial conductivity at 80 ° C even after being exposed to alkali for more than 2500 hours in 1M KOH at 80 ° C. showed

Therefore, in the anion exchange composite membrane according to the present invention, despite the introduction of an anion exchange group with a substitution degree of 70% or more in the anion exchange polymer, polyphenylene sulfide is used as a porous support to have excellent mechanical properties and excellent alkali stability. It was confirmed that this can be achieved.

Therefore, the anion exchange composite membrane of the present invention is expected to be modular and commercializable as it has excellent mechanical properties and alkali stability at the same time.

Claims (16)

1. A porous support containing polyphenylene sulfide (PPS); and

   An anion exchange composite membrane comprising an anion exchange layer prepared from a composition containing an anion exchange polymer filled in the porous support and having a repeating unit represented by any one selected from the following <Formula 1> to <Formula 3> .

   <Formula 1>

   

   <Formula 2>

   

   <Formula 3>

   

   (In Formulas 1 to 3, A is any one selected from compounds represented by the following structural formulas,

   

   ,

   

   ,

   

   ,

   

   Where x, n, o, p, q, and r are mole fractions in the repeating unit, respectively, x, n, o, p, q, and r are all greater than 0, o + p + q + r = 1, and y Is an integer selected from 1 to 6)
2. According to claim 1,

   The anion exchange composite membrane, characterized in that the composition further comprises a crosslinking agent.
3. According to claim 2,

   The crosslinking agent is N,N,N',N'-tetramethylmethylenediamine (TMMDA), N,N,N',N'-tetramethylethylenediamine (TMEDA), N,N,N',N' -Tetramethyl 1,3-propanediamine (TMPDA), N,N,N',N'-tetramethyl-1,4-butanediamine (TMBDA), N,N,N',N'-tetramethyl An anion characterized by being at least one selected from the group consisting of 1-1,6-hexanediamine (TMHDA) and N,N,N',N'-tetraethyl-1,3-propanediamine (TEPDA) Exchange complex membrane.
4. According to claim 1,

   The anion exchange composite membrane, characterized in that the polyphenylene sulfide is a cross-linked or linear polyphenylene sulfide having a weight average molecular weight of 10000 or more and a degree of dispersion obtained by dividing the weight average molecular weight by the number average molecular weight of 2.5 or less.
5. According to claim 1,

   The polyphenylene sulfide has a stiffness of 3 to 4 GPa, a strength at break of 50 to 80 MPa, and a strength at yield of 50 to 80 MPa, an anion exchange composite membrane. .
6. According to claim 1,

   In Formulas 1 to 3, x = 0.7 to 0.9, n = 0.7 to 0.9, o + p + q + r = 1, o = 0.7 to 0.9, p + q + r = 0.1 to 0.3, characterized in that Anion exchange composite membrane.
7. (I) preparing a porous support containing polyphenylene sulfide (PPS);

   (II) dissolving an anion exchange polymer having a repeating unit represented by any one selected from <Formula 1> to <Formula 3> described in claim 1 in a second solvent to obtain a polymer solution; and

   (III) impregnating the porous support with the polymer solution and drying it;
8. According to claim 7,

   The method of manufacturing an anion exchange composite membrane, characterized in that the polymer solution further comprises a crosslinking agent.
9. According to claim 7,

   The crosslinking agent is N,N,N',N'-tetramethylmethylenediamine (TMMDA), N,N,N',N'-tetramethylethylenediamine (TMEDA), N,N,N',N' -Tetramethyl 1,3-propanediamine (TMPDA), N,N,N',N'-tetramethyl-1,4-butanediamine (TMBDA), N,N,N',N'-tetramethyl An anion characterized by being at least one selected from the group consisting of 1-1,6-hexanediamine (TMHDA) and N,N,N',N'-tetraethyl-1,3-propanediamine (TEPDA) Exchange complex membrane.
10. According to claim 7,

    The first solvent and the second solvent are the same as or different from each other, and each independently N-methyl-2-pyrrolidone, dimethyl sulfoxide, dimethylformamide, diethylformamide, dimethylacetamide, tetrahydrofuran, methanol , A method for producing an anion exchange composite membrane, characterized in that at least one selected from the group consisting of ethanol and ether.
11. According to claim 7,

    The method for producing an anion exchange composite membrane, characterized in that the concentration of the polymer solution is 2 to 5% by weight.
12. According to claim 7,

    In the step (I), the porous support is subjected to carding, garneting, air-laying, wet-laying, melt blowing, spun bonding ( A method for producing an anion exchange composite membrane, characterized in that it is produced by any one method selected from the group consisting of spunbonding and stitch bonding.
13. According to claim 7,

    The drying in step (III) is characterized in that the second solvent is completely removed by first drying in an oven at 80 to 90 ° C for 1 to 10 hours and then drying in a vacuum oven at 110 to 150 ° C for 20 to 30 hours. A method for producing an anion exchange composite membrane.
14. An alkaline fuel cell comprising the anion exchange composite membrane according to any one of claims 1 to 6.
15. A water electrolysis device comprising the anion exchange composite membrane according to any one of claims 1 to 6.
16. A redox flow battery comprising the anion exchange composite membrane according to any one of claims 1 to 6.

Images