KR100453680B1 - Crosslinked proton exchange membrane and its preparation - Google Patents

Abstract

The present invention relates to an ion exchange membrane in the form of a film in which a copolymer including a structural unit capable of causing a crosslinking reaction and a structural unit substituted by an ion conductive group is crosslinked with each other, and a method of manufacturing the same. The conductivity of the ions is less affected by moisture and methanol, and can solve the methanol crossover can be used in a variety of electrochemical devices, including fuel cells.

Description

Cross-linked ion exchange membrane and its manufacturing method {CROSSLINKED PROTON EXCHANGE MEMBRANE AND ITS PREPARATION}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ion exchange membrane and a method for producing the same, and more particularly, to an ion exchange membrane for a fuel cell and a method for producing the same.

The fuel cell, which has been spotlighted as an alternative power source, is an electrochemical device that is highly efficient in converting hydrogen and oxygen contained in hydrocarbon fuel such as methanol and natural gas into electric energy directly by electrochemical reaction. Since the development of clean power technology for power supply of spacecraft in the United States in the 1970s, research has been conducted to use it as a general power source. Currently, the United States, Japan, and Europe are actively developing for practical use in advanced countries. have. A lot of research is being carried out mainly for use as transportation and on-site power supply. Fuel cells with low operating temperature and convenient system miniaturization, mobility and portability are proton exchange membrane fuel cell (PEMFC) using hydrogen directly as fuel and direct methanol fuel cell using methanol directly as fuel. Methanol Fuel Cell (DMFC). DMFC, which uses methanol directly as a fuel, uses liquids such as methanol mixed with water as fuel, and has an advantage of miniaturization because of easy fuel handling and low operating temperature. Such fuel cells are attracting attention as an optimal motive power for replacing primary and secondary batteries, which are environmental pollutants at the time of disposal.

The main body of the fuel cell is a unit cell formed by attaching, by hot pressing, an anode into which fuel enters and a cathode into which air enters, on both sides of an electrolyte made of a polymer ion exchange membrane. The unit cells are stacked in layers to form a fuel cell power generation system ranging from several kW to several MW.

PEMFCs or DMFCs, which have various advantages and efficiency advantages, are still not commercialized due to the high production cost as well as technical problems to be solved. The biggest obstacle to the commercialization of PEMFC and DMFC is due to the failure of the developed ion exchange membranes to reach this orbit.

It is no exaggeration to say that the performance of the ion exchange electrolyte membrane in PEMFC or DMFC depends on the performance of the fuel cell. The polymer membrane used for PEMFC and DMFC not only has to move hydrogen ions generated from the anode to the cathode, but also plays an important role in separating two reactants (fuel such as hydrogen or methanol and oxygen as an oxidant). Therefore, the requirements of the polymer ion exchange membrane for fuel cells should be excellent in hydrogen ion conductivity, while the conductivity of electrons should be low. In addition, the flow of the reactant or water should be less than that of ions, and the gas impermeability, shape stability, mechanical and chemical stability should be high. As the reactants pass through the membrane, there is an explosion, an addition reaction, and electrons moving through the membrane, which short-circuits, reducing the power efficiency of the fuel cell or even causing it to fail. Polymer membranes used in DMFCs must have less migration of other molecules (methanol, water) in addition to the requirements of PEMFC.

Fuel cell membranes developed and commercialized so far are PEMFC's Nafion of DuPont, USA, XUS of Dow Chemical, Gore-Select of Gore & Associates, BAM3G of Ballard Advanced Materials of Canada, Japan Asahi Chemical's Aciplex, Asahi Glass's Flemion, Chlorine Engineer's Pride C, Tokuyama Soda's Neosfeta-F, Germany's Festa, etc. Sulfonated polystyrene-block-poly (ethylene-ran-butylene) -block-polystyrene (hereinafter referred to as "SSEBS") (US) Only a small number (US 6,110,616) other than 5,679,482 and US 5,468,574 are commercialized.

In the case of fluorine-based membranes, sufficient efficiency can be obtained for PEMFC, but it is not suitable for commercialization due to its high price and price, and various side effects occur when PEMFC polymer membrane is used in DMFC. Otherwise, there is a problem in using methanol as a fuel. The generation of "methanol crossover", in which methanol as a fuel passes through the polymer ion exchange membrane directly from the anode to the cathode, causes a decrease in cathode potential and a loss of battery voltage. In addition, this methanol crossover results in enormous loss of fuel itself and low energy efficiency.

Therefore, in order to commercialize DMFC, it must be a film that can solve the crossover of methanol as well as a price competitive film.

In general, the currently developed Nafion-based fluorine or non-fluorine-based SSEBS membrane has a hydrophobic main chain and a hydrophilic sulfonic acid group in the polymer chain, so that the phase separation between the hydrophilic and hydrophobic chains is finely formed, thereby bridging the hydrophobic chains. It acts like a crosslinkage point and has a physical gel shape to maintain mechanical stability. Such membranes are known to cause hydrophilic chains to form ion channels in the presence of water, thus expanding the membrane and transferring hydrogen ions through the formed ion channels. In general, in the case of PEMFC, the ion channel formed by the water is expected to play a positive role because water must be present inside the membrane.

However, one of the ways to increase the activity of the catalyst to increase the power density is to operate the fuel cell at a high temperature is essential, so that the expansion force according to the temperature of the chain of hydrophobic groups that give mechanical strength is greater than the gel forming force As a result, dehydration occurs, and hydrophobic chains are softened due to an increase in temperature, resulting in a collapse of the membrane. In other words, the mechanical strength is significantly reduced.

The problem with swelling of the membrane is more pronounced in the case of DMFC using liquid fuel. When methanol, the swelling agent of a Nafion membrane, is used as fuel, methanol expands the ion channel further, reducing the mechanical strength of the membrane, as well as methanol crossover, where the fuel methanol moves from the anode to the cathode along with hydrogen ions and water. It causes a problem.

In the case of commercially produced Nafion, if the thickness of the film is too thin, it is generally produced thick because there is no mechanical strength. That is, a thickness of 50 μm or less is not used in actual fuel cells. This is disadvantageous in terms of miniaturization, light weight, and price. In order to increase the strength of the membrane is generally prepared by impregnating the ion conductive polymer material in the polymer support having a hole. (US 6,248,469, US 5,547,551) However, this method is problematic due to the high failure rate that does not prevent the movement of fuel by phase separation between the support and the ion conductive material. That is, up to now, a membrane that has a competitive price, high ion conductivity and mechanical strength, high resistance to dehydration and high chemical stability, and satisfies all conditions in which fuel permeation does not occur at a high temperature has not been developed.

Accordingly, it is an object of the present invention to provide a polymer ion exchange membrane that exhibits low swellability even when using a liquid fuel that is high temperature, high pressure or swelling agent.

Another object of the present invention is to provide an ion conductive polymer ion exchange membrane having high ion conductivity, low resistance to dehydration, high mechanical properties, and low gas permeability.

Another object of the present invention is to produce an ion conductive polymer membrane which has little electrical conductivity, has structural stability, and does not easily break when dried or expanded.

It is still another object of the present invention to provide a polymer ion exchange membrane that can also be used in DMFC using methanol directly as fuel.

It is yet another object of the present invention to provide polymeric ion exchange membranes that contribute to the commercialization of PEMFCs or DMFCs using materials and methods that are cost-effective in making membranes.

It is still another object of the present invention to provide highly competitive materials for electrochemical devices such as electrolyzers, electrolysis, electrodialysis, diffusion dialysis, pressure dialysis, chloro-alkali separators, batteries, as well as ion conductive membranes for fuel cells. To provide.

It is another object of the present invention to provide a method for preparing the ion exchange membrane. Another object of the present invention is to provide a membrane electrode device (MEA: Membrane Electrode Assemblies) including the ion exchange membrane.

1 is a schematic diagram of water swelling characteristics of an uncrosslinked ion exchange membrane obtained through sulfonation of a non-fluorine-based linear polymer (SSEBS is selected as a model).

2 is a schematic diagram of water swelling characteristics of the crosslinked ion exchange membrane of the present invention.

1 and 2 Represents an unsulfonated chain, Represents a sulfonated chain.

The present invention has a unit structure that can have an ion conductive group or can be substituted with an ion conductive group, and also a copolymer containing a functional group capable of causing a crosslinking reaction is formed into a gel of three-dimensional network structure by crosslinking by covalent bonds. The present invention relates to a polymer ion exchange membrane in the form of a film in which an ion conductive group is introduced into a gel of a three-dimensional network structure, and to a polymer ion exchange membrane in which the conductivity of hydrogen ions is less affected by moisture and methanol.

More specifically, in the present invention, a crosslinking point is formed by a crosslinking reaction from a structural unit A selected from the group consisting of Formula 1 and Formula 2 below, and the structural unit B selected from the group consisting of Formula 3 and Formula 4 The copolymer comprising an ion exchange membrane in the form of a crosslinked with each other.

-ArR _7-

In the above Chemical Formulas 1 to 4, R _1, R _2, R _3, R ₄ and R ₅ are each independently hydrogen, phenyl, C _1-4 lower alkyl, C _1-4 lower alkylene, C _1-4 lower alkynyl Nyl, nitrile or a reactor capable of independently inducing a condensation reaction, for example epoxy, cyanate, ester, halogen. R ₆ represents hydrogen or a lower alkyl group of C _1-4 , and Ar represents a substituted or unsubstituted phenyl group, wherein the substituent is phenyl, C _1-4 lower alkyl, C _1-4 lower alkylene, C _{1- 4} lower alkynyl, R ₇ represents —SO ₃ H, —COOH, or —P (O) (OR ₈ ) OH group, wherein R ₈ represents hydrogen or a C _1-4 lower alkyl group. It is preferred that R ₇ is -SO ₃ H.

The hydrophobic chain (structural unit A) which does not contain an ionizing substance in the ion exchange membrane component forms a crosslinking point by a crosslinking reaction to fix its structure, and serves to maintain the strength of the membrane. By fixing the structure of the membrane, the ion exchange membrane of the present invention does not dissolve the gel in any solvent even if a large number of ion conductive groups selected from the group consisting of -SO ₃ H, -COOH, or -P (O) (OR ₈ ) OH group are substituted. It is possible to add an excessive amount of the ionizing material by using a property that does not have a high ion conductivity. In addition, since the hydrophobic portion that maintains the mechanical strength of the membrane is fixed at the crosslinking point, the presence of methanol as a swelling agent inhibits the swelling of the membrane, thereby preventing the diffusion of methanol and other substances through the membrane. It can be usefully used as.

1 shows a model for the problem of membranes prepared without chemical crosslinking points via covalent bonds, specifically a conventional ion exchange membrane, sulfonated polystyrene-block-poly (ethylene-random-butylene) block-polystyrene (SSEBS) (US Pat. No. 5,679,482) shows the manufacturing process and problems. Polystyrene-block-poly (ethylene-random-butylene) block-polystyrene (SEBS) is used to control the temperature or concentration in the affinity between hydrophobic chains and the affinity between hydrophilic chains after sulfonation progresses (step A in FIG. 1). Thereby forming a "reversible physical gel" that can be reversibly controlled equilibrium (step B of Figure 1). In other words, hydrophilicity and hydrophobicity in one polymer chain cause hydrophobic portions with other polymer chains to form a microdomain, which forms a physical crosslinking point in water. However, this "reversible physical gel" has a profound swelling of the membrane in water, especially in the presence of methanol, due to the affinity of the ion-conducting group to water, resulting in a significant methanol crossover when used in DMFC, resulting in It will not be used (step C of Figure 1). Sometimes, when an ion conductive group (for example, a sulfone group) is excessively substituted, there exists a danger that the ion exchange membrane itself may melt | dissolve.

FIG. 2 illustrates a functional model of a crosslinked ion exchange membrane according to the present invention, wherein a gel covalently crosslinked through a structural unit A serving as a crosslinking point, that is, an irreversible chemical gel state In structural unit A, the structure of the membrane can be fixed to significantly reduce the amount of expansion and contraction according to the surrounding situation. In other words, even if a polar substance such as water or methanol is present, the expansion of the membrane can be significantly reduced. In addition, even if the ion conductive group is excessively substituted, the problem of dissolving the ion exchange membrane itself by structural fixation can be solved. According to a specific embodiment of the present invention, the expansion of the ion exchange membrane was not large even when the sulfonation proceeded excessively. Furthermore, the phenomenon in which the ion exchange membrane itself was dissolved was not found. Therefore, an ion exchange polymer film having a high ion conductivity in which an ion conductive group is excessively introduced can be produced. This result is believed to be because shape stability (or structural stability) has been imparted by the formation of irreversible chemical gels.

The ion exchange membrane of the present invention described above preferably has a -SO ₃ H, -COOH or -P (O) (OR ₈ ) OH group which acts as an ion conducting group of at least 15%, more preferably 15-80%, even more It is preferably 20-70%, most preferably 30-70% substituted membrane, with significantly improved shape stability than membranes made from SSEBS having a degree of substitution of 30%. From the advantages of this shape stability, it is possible to achieve higher amounts of sulfonation than conventional methods to increase ionic conductivity. According to the experimental example of the present invention, the ion exchange membrane of the present invention exhibits an ion conductivity of at least 1 × 10 ⁻⁵ or more, preferably 1 × 10 ^{−5 -5} × 10 ⁻¹ , specifically, a styrene unit unit When the ratio of the sugar sulfonating unit unit 1: 1: 0.1 showed an ion conductivity of 3.4 × 10 ^-4 , when the ratio is 1: 4, the ion conductivity was about 3.4 × 10 ^-2 .

In the ion exchange membrane according to the present invention, after preparing a polymer solution of a copolymer having the structural unit A and the structural unit B ', a film is prepared with or without addition of a crosslinking initiator to the polymer solution, When the film is crosslinked by heating and the functional group forming the ion channel in the benzene ring is substituted with less than 20%, the crosslinked film is swelled by dipping in the solvent, and then -SO, a functional group for forming the ion channel in the benzene ring. It can be prepared by further introducing a ₃ H, -COOH or -P (O) (OR ₈ ) OH group.

Preferably, the ion exchange membrane according to the present invention is prepared through the following steps.

a) preparing a polymer solution from a copolymer of structural unit A selected from the group consisting of Formula 1 and Formula 2 below and structural unit B ′ selected from the group consisting of Formula 3 and Formula 4 below,

b) adding the crosslinking initiator to the obtained polymer solution or solution, and then preparing a film;

c) crosslinking the film by light irradiation or heating,

d) When the degree of substitution of the ion conductive group is less than 15%, the cross-linked film is swelled by dipping in a solvent, and then -SO ₃ H, -COOH, or -P (O) ( OR ₈ ) introducing an OH group.

Formula 1

Formula 2

Formula 3

Formula 4

-ArR _7-

In the above Chemical Formulas 1 to 4, R _1, R _2, R _3, R ₄ and R ₅ are each independently hydrogen, phenyl, C _1-4 lower alkyl, C _1-4 lower alkylene, C _1-4 lower alkynyl Nyl, nitrile or a reactor capable of independently inducing a condensation reaction, for example epoxy, cyanate, ester, halogen. R ₆ represents hydrogen or a lower alkyl group of C _1-4 , and Ar represents a substituted or unsubstituted phenyl group, wherein the substituent is phenyl, C _1-4 lower alkyl, C _1-4 lower alkylene, C _{1- 4} lower alkynyl, R ₇ represents hydrogen or an ionic conductive group selected from the group consisting of —SO ₃ H, —COOH and —P (O) (OR ₈ ) OH groups, wherein R ₈ represents hydrogen or C _{1 -4} lower alkyl group.

Although both methods of crosslinking from a copolymer having an ion conductive group or additionally introducing an ion conductive group after crosslinking have advantages, both methods are preferable for increasing ion conductivity and decreasing solvent swelling characteristics. Is as follows. Ionic conductivity depends on the degree of substitution of the ion conductive group, for example, the degree of sulfonation. Therefore, in order to increase the ion conductivity, it is intended to increase the substitution degree of the ion conductive group. However, in the case of a general linear polymer, if the sulfonation is advanced to a certain level or more, the polymer is completely dissolved in water, and thus has a disadvantage in that a membrane cannot be formed. In other words, if the degree of sulfonation is increased to increase the ion conductivity, the ion conductivity is increased. If the sulfonation is increased to increase the ion conductivity, insoluble polymers are dissolved in water. For example, in the case of polystyrene, at least 70% of the sulfonated polystyrene becomes soluble in water and becomes unstable. However, in the case of the cross-linked product in advance, the structural stability of the ionic conductive group (for example, -SO ₃ H, -P (O) (OR ₈ ) OH, -COOH) is dissolved in water even if the excess is introduced, etc. Can be significantly reduced, and an excess of an ion conductive group can be introduced. However, when using the former method, it is natural that this problem can be partially solved by introducing a small amount (not insoluble in water) of the ion conductive group and additionally introducing the ion conductive group into the crosslinking product.

Hereinafter, the method of the present invention will be described in more detail.

The copolymer including the structural units A and B 'may have four basic structures, specifically, a random copolymer in which the structural units A and B' are arranged without having regularity, An alternating copolymer in which the structural units A and B 'are present in alternation, a block copolymer in which the structural units A and B' each form a block, and a structural unit A forms the main chain, B ′ may have a structure of a graft copolymer (see Table 1) to form a side chain.

Type of copolymer Molecular structure Random copolymer -AAB'B'AB'B'AB'AAAB'- Block copolymer -AAAAAAB'B'B'B'B'B'- (di-block copolymer) -AAAAAAB'B'B'B'B'B'AAAAAA- (tri-block copolymer) Alternating copolymer -AB'AB'AB'AB'AB'AB'- Graft copolymer

These choices may be appropriately selected in consideration of required physical properties, and their choices are well known to those skilled in the art. For example, when more precise control of physical properties is required, it may be desirable to select block copolymers. In addition to the above four basic structures, the copolymer may be obtained using a combination of the above basic structures or three or more monomers, and the present invention includes them. The molecular weight of the copolymer usable is not particularly limited but is preferably in the range of 20,000-1,000,000 grams / mole. Copolymers having such a molecular weight have the advantage of being widely commercialized and readily available.

In the above copolymer, the structural unit A increases the flexibility of the film and serves as a crosslinking point for forming a three-dimensional network gel in which the crosslinking reaction occurs by irradiation or heating of a light source. For example, in the case of Formula 1, hydrogen bound to carbon is dropped by gamma ray irradiation to form an alkyl radical, which radical forms a crosslink with a chain of another copolymer, resulting in a three-dimensional network structure. To form. The obtained three-dimensional network structure has the form of a gel. Furthermore, when substituted by a reactor capable of independently inducing condensation reactions such as epoxy, cyanate, ester, halogen, crosslinking of the copolymer can be more easily achieved by standard methods known in the art. . On the other hand, in the case of Formula 2, since it has a π bond in the molecular structure, it can be irradiated with light of lower energy than gamma rays such as UV and IR, or can be crosslinked by heating. The selection of a light source, the heating conditions, and the like at the time of crosslinking by irradiation or heating of light may be performed as is well known to those skilled in the art. Preferably, structural unit A has a structure of formula (2). The reason for this is that not only the crosslinking can be easily achieved as described above, but also the π bond in the molecular structure, that is, the rubber component, has a good contact force with the metal catalyst when producing the unit cell of the fuel cell. This is because there is an advantage that can be reduced. Preferred examples of the compound having the structural unit A include ethylene, butylene, butadiene and propylene. Furthermore, they may be substituted with nitrile, epoxy, cyanate, ester, halogen.

The structural unit B 'imparts ion conductivity to the ion exchange membrane by an ion conductive group such as -SO ₃ H, -COOH or -P (O) (OR ₈ ) OH group (by sulfonation, carboxylation or phosphorylation, etc.) Function. Examples of compounds having structural unit B '(or which can provide structural unit B by introduction of an ion conductive group) include polystyrene, poly (α-methylstyrene), poly (triphenylphosphine oxide sulfide-phenylsulfone -Ionic conduction groups such as sulfide), poly (2-phenylsulfide-1,4-phenylene), poly-X (Maxdem), diphenyl poly (2,6-diphenyl-1,4-phenylene oxide) And a compound in which a phenyl group capable of being substituted in the main chain, that is, a phenyl group is pendant to the main chain, preferably polystyrene or poly (α) capable of introducing an ion conductive group under mild conditions. Another example is a polymer composed of units having a phenyl group in the main chain, rather than having a phenyl group pendent in the main chain, and an example of such a polymer is poly (bisbenzo). Azole-1,4-phenylene, poly (benzo (r) -Thiazole) -1,4-phenylene, poly (benzo (bis-diazole) -1,4-phenylene, polyaramid (Kevlar), polyphenylene sulfone, polysulfone, polyether sulfone, polyether- Ether sulfone, polyarylether sulfone, polyimide, poly (2,6-dimethyl 1,4-phenylene oxide, polyphenylene sulfoxide, polyphenylene sulfide, polyphenylene sulfide sulfone, polyparaphenylene, poly ( Phenylquinooxaline, polyether ketone, polyether ether ketone, polyether ketone ketone, polyether ether ketone ketone, polyether-ether ketone-ketone, polyetherimide, polyphenylsulfone, poly (hexafluoroisopropylidene dione Hydride / metaphenylene diamine), poly (hexafluoroisopropylidene dianhydride / diaminodiphenyl sulfone), polyvinyl sulfonic acid, poly (hexafluoroisopropylidene dianhydride / polyaminodiphenoxy Benzene, poly ( Pyrrolymetic diimide-1,3-phenylene), poly (diphthalimide-1,3-phenylene), poly (1,4-phenylene oxide), poly (benzophenone sulfide), poly (benzo And phenone sulfide phenylsulfone-sulfide, Preferably, the benzene ring is included in the copolymer at least 20%, more preferably 20-60%, most preferably 20-30%. When the content of the benzene ring is 20% or less, the ion conductivity of the ion exchange membrane is decreased, which may lower the membrane properties. On the other hand, in the case of copolymers or homopolymers such as polyvinylcarboxylic acid, poly (tripulostyrene sulphonic acid), poly (vinyl phosphoric acid), and polystyrene sulfonic acid, which already have ion conductivity in the chain, a film form After preparing the membrane, the ion conductive membrane with high mechanical strength can be prepared by inducing crosslinking reaction by giving energy such as gamma ray irradiation. In this case, since the ionic conductivity is dependent on the conductive group already present in the chain, the swelling resistance to the solvent or water is increased according to the characteristics of the gel, so that the methanol crossover is not increased, but the ionic conductivity does not change or is higher than that of the starting material. Can be small. In this case, the film formed of the gel may be further substituted with an ion conductive group such as sulfonation to prepare a high performance membrane.

The copolymer including the structural units A and B 'described above is first dissolved in a suitable solvent to form a polymer solution of the copolymer. Examples of the solvent that can be used to form the polymer solution are not particularly limited, but aromatic solvents such as benzene, toluene, xylene, and the like, and chlorinated solvents such as 1,2-dichloroethane, trichlorobenzene, methylene chloride, and the like solvent), a hydrocarbon solvent such as cyclopentane, cyclohexane, cycloheptane, or a mixed solvent thereof.

After adding a crosslinking initiator (or photoinitiator) to the obtained polymer solution, it is manufactured in the form of a film with or without addition. Examples of crosslinking initiators that can be used in the process of the present invention are benzophenone (BZP from Aldrich), 2,6-bis (azidobenzylidene) -4-methylcyclohexanone (bisazido from Aldrich), 2,2-dime Oxy-2-phenylacetophenone (Irgacure 651 from Ciba), 1-benzoyl-1-hydroxycyclohexane (Irgacure 184 from Ciba), 2,4,6-trimethylbenzoyldiphenylphosphine oxide (Lucirin TPO from BASF) Although not limited thereto, a crosslinking initiator commonly used in the art may be widely used. The amount of the crosslinking initiator used is usually added within the range of 0.001-10 wt% based on the weight of the polymer. Preferably it is used in the amount of 0.01-5 wt%. In the present invention, if necessary, a crosslinking agent may be further added to control the degree of crosslinking, for example, m- or p such as 1,4-cyclohexanediobismethacrylate. -Divinylbenzene, ethylene glycol dimethacrylate, and the like, but are not limited thereto. Furthermore, additional halides, nitrogen monoxide, sulfur monochloride, or triplet oxygen, peroxides, hydroperoxides, peroxy radacal, etc. may be added to promote the crosslinking reaction. Can be.

The method of manufacturing in the form of a film can be accomplished by various methods. For example, the film form may be prepared by simply evaporating the solvent slowly, or by casting, for example by casting using a Gardner knife.

The crosslinking reaction of the copolymer may occur by light irradiation or heating as described above, and the heating temperature may be appropriately adjusted according to the type of the copolymer, and these are well known in the art. When crosslinking is achieved by light irradiation, examples of light sources include light energy such as microwave, IR, UV or visible light, nonparticulate radiation such as x-rays and gamma rays, alpha particles, beta particles and high energy electrons. And particulate radiation such as protons and neutrons. The most common light sources commercially available are ⁶⁰ Co and high energy electron accelerators, UV, visible light and infrared light. In addition, a plasma radiation source may be used.

source wave length, nm mercury arclow pressuremedium pressurehigh pressure 254365,436,546,580 460-480 visible light sources, metalhalide lamps 400-760 gas-fired infrared-generating systems; electricallypowered infrared-generating systems near 0.76-2.5fundamental2.5-25far 25-500 lasers single wavelengths

Crosslinked copolymers that do not have an ion conductive group are introduced into the benzene ring by ionization groups such as -SO ₃ H, -COOH, or -P (O) (OR ₈ ) OH groups by sulfonation, carboxylation or phosphorylation. . The sulfonation, carboxylation or phosphorylation reaction is accomplished by dissolving a compound comprising a benzene ring in a suitable solvent and then reacting with a sulfonating agent, a carboxylating agent, a phosphorylating agent, and such a reaction is conventionally known in the art. It is well known to those with knowledge. For example, sulfonation can be accomplished by heating the polymer in the presence of sulfuric acid, or by adding a small amount of silver sulfate as a catalyst. In addition, phosphorus pentaoxide, triethyl phosphate and tris (2-ethylhexyl) phosphate may be added as catalysts to control the reactivity of SO ₃ . Furthermore, sulfuric acid / acetic anhydride, sulfur / trioxide / acetic acid, SO ₃ / acetic acid, SO ₃ / lauric acid, chlorosulfonic acid, trimethylsilylsulfonylchloride and the like can also be used (US Pat. No. 5,679,482). Reference). Phosphorylation can be carried out by methods well known in the art, for example, by the method of Joachim Engels (see Korean Patent Publication No. 1986-007273). In addition, various methods of carboxylation are well known in the art, and for example, the carbonyl compound may be prepared as a carboxylated compound by reacting the carbonyl compound with hydrogen peroxide in the presence of an organic arsenic acid.

Such reactions are usually carried out under chlorolated hydrocarbon solvents (eg 1,2-dichloroethane, trichlorobenzene, methylene chloride), hydrocarbon solvents (eg cyclohexane, cyclopentane) or mixed solvents thereof. Is performed.

Such polymer membranes can significantly reduce the possibility of methanol crossover by crosslinking hydrophobic chains that determine mechanical strength and size of ion channels and permanently fixing them through covalent bonds. Furthermore, the polymer membrane of the present invention can introduce a greater amount of ion conductive groups than the polymer membrane disclosed in US Pat. No. 5,679,482, and has the advantage of improving ion conductivity by introducing more than 20% of ion conductive groups while maintaining shape stability. have.

On the other hand, the above-described production method of the present invention described a crosslinking of the copolymer comprising a structural unit A having a functional group capable of causing a crosslinking reaction by a covalent bond and a structural unit B 'which improves ionic conductivity. Instead of inducing a crosslinking reaction from the chain, a polymer can be synthesized from the monomers and at the same time a crosslinking reaction can be induced. Therefore, the present invention is not limited to the crosslinking reaction of the polymer chain.

The present invention also relates to an electrochemical device comprising the ion exchange membrane described above, wherein the ion exchange membrane is an electrochemical device such as electrolysis, electrodialysis, diffusion dialysis, pressure dialysis, electrolyzer, chloro-alkali separator, battery It can be widely used in electrochemical devices such as. Preferably, the present invention relates to a fuel cell including the ion exchange membrane, wherein the ion exchange membrane is positioned between a cathode portion including a cathode and an anode portion including a cathode to serve as an electrolyte membrane and a separator. Done. The cathode and anode portions that can be used in such a fuel cell are not particularly limited, and those that have been widely used in the fuel cell field may be applied. More preferably, the ion exchange membrane is used in a direct methanol fuel cell using methanol as an organic fuel and a polymer electrolyte fuel cell using hydrogen as a direct fuel.

The following examples are intended to illustrate the invention in more detail, but the invention is not limited thereto.

Example

<Example 1-5>

Polystyrene-block-polybutadiene-block-polystyrene (SBS; molecular weight 140,000, 30 wt% styrene) was purchased from Aldrich, and phenolic antioxidants were removed via reprecipitation. The reprecipitated copolymer was dissolved in toluene at 5 wt%, and then 2,4,6-trimethylbenzoyldiphenylphosphine oxide (Lucirin TPO from BASF), a photoinitiator, was dissolved in the polymer solution at a ratio of 1 wt% of high molecular weight. Added. The polymer solution is poured into a petri dish in an appropriate amount and slowly blown toluene indoors for a week to obtain a film. It is generally known that triblock copolymers cause fine phase separation resulting in channels of styrene of several nm. The resulting film was irradiated with UV for 1 hour to form a gel, and then poured into dichloroethane (DCE; Junsei) and swollen. Meanwhile, acetic anhydride and H ₂ SO ₄ were added to DCE to prepare a 0.1N solution (hereinafter referred to as AASO 3). ASO 3 was slowly added to the SBS membrane swollen in DCE at 0 ° C. and left at 0 ° C. for 1 hour, followed by 2 hours in a 35 ° C. thermostatic bath to induce a reaction. Depending on the amount of AASO3 solution added, the color changes from reddish yellow to dark purple over time. After the reaction was completed, 1-propanol was added to terminate the remaining activity of AASO3, and after 30 minutes, the membrane was taken out, dried in air, and washed with distilled water at least 10 times. After this, wash with ethanol at least 5 times and again with boiling distilled water at least 5 times. The washed membrane was washed 10 times or more with tertiary distilled water and ionic conductivity was measured. Table 3 shows the ion conductivity values and swelling characteristics of the membranes obtained according to the total amount of AASO 3 added in Table 3. Each film is less than 100 μm thick.

Styrene: AASO3 equivalence ratio Ion conductivity Swelling in water Example 1 1: 0.1 3.4 x 10 ^-4 No swelling Example 2 1: 0.5 2.4 x 10 ^-3 No swelling Example 3 1: 1 5.9 x 10 ^-3 No swelling Example 4 1: 2 1.8 x 10 ^-2 3% swelling Example 5 1: 4 3.4 x 10 ^-2 5% swelling

<Example 6-9>

After preparing a polymer solution in the same manner as in Example 1 and making a film, a UV irradiation time was 5 minutes to make a gel, a film was prepared in the same manner as shown in Table 4 below. The equivalent ratio of styrene: AASO3 added was 1: 2.

Thickness (㎛) Ion conductivity Swelling in water Example 6 57 1.5 x 10 ^-2 2% swelling Example 7 82 9.7 x 10 ^-3 No swelling Example 8 79 5.2 x 10 ^-2 5% swelling Example 9 75 6.7 x 10 ^-2 7% swelling

<Example 10>

The membrane was prepared in the same manner as in Example 5 above using polystyrene-block-polyisoprene-block-polystyrene (PIP; Aldrich, 22wt% styrene, melt index = 3g / min, viscosity = 12poise). Ion conductivity was sulfonated by adding 2 times the amount of AASO 3 of the basic styrene unit, and the obtained membrane had an ion conductivity of 7.9 × 10 ⁻² .

<Example 11>

The membrane was prepared in the same manner as in Example 5 above using polystyrene-block-polybutadiene (SB; 30 wt% styrene, melt index = 10 g / min, viscosity = 8.5 poise, Aldrich) and the obtained ion conductivity was 5.7 × 10. Was ^-2 .

<Example 12>

Preparation of ion conductive polymer membrane by the method of Example 5 above using polystyrene-block-polybutadiene-block-polystyrene (SBS-branched; 21 wt% styrene, melt index <1g / 10min, viscosity = 2900 cps; Aldrich) It was. Ionic conductivity was 1.3 × 10 ⁻² .

<Example 13>

Polystyrene-block- (polyethylene-random-butylene) -block-polystyrene (SEBS; Mw = 118,000, 28 wt% styrene, viscosity = 1500cps; Aldrich) was dissolved in toluene to prepare a 5 wt% solution and then poured into a petri dish. The solvent is slowly blown off at room temperature to prepare a membrane. Gamma rays were irradiated to the obtained film at 30 Mrad to obtain a gel. The following reaction yielded an ion conductive polymer membrane under the sulfonation conditions of Example 5. Ionic conductivity was 3.5 × 10 ⁻² .

<Example 14>

The membrane of Example 13 was gamma-ray 10 Mrad and the gel was prepared, and then an ion conductive polymer membrane was prepared through sulfonation. Ionic conductivity was 6.4 × 10 ⁻² .

<Example 15>

The copolymer of Example 1 was made into a 30 wt% solution (including 1 wt% photoinitiator), pushed with a Gardner knife to cast into a film, and then volatilized in air to prepare a membrane, and sulfonation was carried out under the conditions of Example 5. I was. Ionic conductivity was 7.2 × 10 ⁻² .

<Example 16>

The polymer solution of Example 15 was cast in a film form by pushing with a Gardner knife, and immediately immersed in an ethanol solvent to induce phase separation to prepare a film in film form. After sulfonation under the conditions of Example 5 and neutralized with propanol, the membrane was immediately taken out and slowly dried on a teflon plate, and the obtained membrane was washed 10 times with distilled water, 10 times with alcohol and 10 times with boiling distilled water, and then washed with 3 distilled water. After soaking for 1 day, the ion conductivity was measured. Ionic conductivity was 6.4 × 10 ⁻² .

<Example 17>

The membrane of Example 9 was measured for the permeation characteristics of 10 wt% methanol solution. The amount of methanol permeated was measured by GC, but was not detected by GC during permeation for 2 hours. Although the membrane thickness of Example 9 was only about half the thickness of the conventional Nafion 115 membrane, methanol permeation was not measured. For reference, the Nafion 115 membrane was 1.6 × 10 ⁻⁶ cm / s for the 10 wt% methanol solution.

<Example 18> SO ₃ Sulfonation

1 g of the SBS gel film crosslinked by the method of Example 1 was swollen overnight to 20 g of DCE. To sulfonate, 0.34 wt% of sulfur trioxide (SO ₃ ) solution was added to DCE, and SO was added to the SBS gel above. ₃ solution was added dropwise. Triethylphosphate as much as 3.6 times the number of moles of SO ₃ is dissolved in DCE and the temperature is adjusted to 0 ° C. Put the above SBS sample in triethyl phosphate solution, drop the SO ₃ solution drop by drop to induce the reaction. After 30 minutes, the reactor was raised to room temperature and reacted for 12 hours. The temperature was raised to 80 ° C. until the color turned purple. After the reaction was completed, the solvent was blown out and the propanol was added and washed several times with water and ethanol. The ion conductivity of the obtained membrane was 3.8 x 10 ^-3 S / cm.

<Example 19>

Polystyrene-Random-Polybutadiene-Rubber (SBR; 45 wt% styrene) was purchased from Scientific Polymer Products (USA) and dissolved in dichloroethane (DCE; Junsei) to prepare a 1% solution. Meanwhile, acetic anhydride and H ₂ SO ₄ were added to DCE to prepare a 0.1N solution (hereinafter referred to as AASO 3). In a SBR solution dissolved in DCE at 0 ° C., the equivalent ratio of styrene: AASO 3 was 1: 3, and AASO 3 was slowly added while stirring, and left at 0 ° C. for 1 hour, followed by 2 hours in a 45 ° C. thermostat. Over time, the color of the solution changes from reddish yellow to dark purple. After the reaction was completed, 1-propanol was added to terminate the activity of the remaining AASO 3. To this solution was added photoinitiator 2,4,6-trimethylbenzoyldiphenylphosphine oxide (Lucirin TPO from BASF) at a rate of 1 wt% of high molecular weight. The polymer solution is poured into a petri dish in an appropriate amount and slowly blown toluene indoors for a week to obtain a film. The obtained film was UV irradiated for 1 hour to form a gel, and then washed with distilled water 10 times or more. After this, wash with ethanol at least 5 times and again with boiling distilled water at least 5 times. The washed membrane was washed 10 times or more with tertiary distilled water and ionic conductivity was measured. The thickness of the film is 100 μm or less. The ion conductivity of the prepared membrane was 4.9 × 10 ⁻² S / cm.

<Example 20>

Polystyrene-block-polybutadiene-block-polystyrene (SBS; molecular weight 140,000, 30 wt% styrene) was purchased from Aldrich, and phenolic antioxidants were removed via reprecipitation. This polymer was dissolved in dichloroethane (DCE; Junsei) to prepare a solution of 1%. In a SBR solution dissolved in DCE at 0 ° C., the equivalent ratio of styrene: AASO 3 was 1: 3, and AASO 3 was slowly added while stirring, and left at 0 ° C. for 1 hour, followed by 2 hours in a 45 ° C. thermostat. Over time, the color of the solution changes from reddish yellow to dark purple. After the reaction was completed, 1-propanol was added to terminate the activity of the remaining AASO 3. To this solution, photoinitiator 2,4,6-trimethylbenzoyldiphenylphosphine oxide (Lucirin TPO from BASF) was added at a rate of 1 wt% of high molecular weight. The polymer solution is poured into a petri dish in an appropriate amount and slowly blown toluene indoors for a week to obtain a film. The obtained film was UV irradiated for 1 hour to form a gel, and then washed with distilled water 10 times or more. After this, wash with ethanol at least 5 times and again with boiling distilled water at least 5 times. The washed membrane was washed 10 times or more with tertiary distilled water and ionic conductivity was measured. The thickness of the film is 100 μm or less. The ion conductivity of the prepared membrane was 2.5 × 10 ⁻² S / cm.

<Example 21>

Polystyrene-Random-Polybutadiene-Rubber (SBR; 45 wt% styrene) was purchased from Scientific Polymer products (USA), made into a film, and then sulfonated by the method of Example 4 to ion exchange. The membrane was prepared. The ion conductivity of the prepared membrane was 2.9 × 10 ⁻² S / cm.

<Example 22>

After making poly (ethylene terephthalate) (Aldrich, Mv = 18000) into a film state, gamma ray was irradiated with 10 Mrad to make a gel, and then sulfonated by the method of Example 1 to prepare an ion exchange membrane. The ionic conductivity of the prepared membrane was 5.2 x 10 ^-3 S / cm.

<Example 23>

After sulfonating the linear SEBS polymer under the conditions of Example 3, 5 wt% of the polymer solution was prepared by placing it in DCE, which was placed in a Petri dish and the solvent was slowly evaporated at room temperature. After the obtained film was irradiated with gamma rays at 10 Mrad to make a gel, the ionic conductivity was 2 x 10 ^-2 and the permeability of 10 wt% methanol was 1 x 10 ^-7 cm / s.

<Example 24>

Before making the polymer gel under the conditions of Example 3, in order to control the crosslinking density, a blend solution was prepared from a diacrylate monomer (Ebecryl 150 from UCB) with SBS: diacrylate monomer (80:20), which was then air. The film was dried to prepare a film, and an ion conductive membrane was prepared under the conditions of Example 3. Appearance observation of the obtained ion conductive membrane showed that the mechanical strength of the membrane was increased.

As can be seen from the above examples, the ion exchange membrane of the present invention exhibits an ion conductivity of at least 1 × 10 ⁻⁵ or more, preferably 1 × 10 ^{−5 -5} × 10 ⁻¹ , specifically 30 wt% of styrene In the case of%, when the ratio of styrene and sulfonating agent is 1: 0.1, the ion conductivity was 3.4 × 10 ⁻⁴ , and the ratio was about 3.4 × 10 ⁻² when the ratio was 1: 4. When the styrene was 45 wt%, 0.05 S / cm was obtained when the ratio of styrene and sulfonating agent was 1: 3. The 10% methanol permeability of Nafion 115 is 2 x 10 ^-6 cm ² / s and 1.7 x 10 ^-6 cm ² / s at similar thickness for commercially available SSEBS. In the ion conductive membrane obtained in the present invention, when the ion conductivity was 10 ⁻³ S / cm or less, the experimental equipment could be measured and the permeability of methanol could not be measured. Considering the detection capability of gas chromatography, which is a measuring device, the permeability of 10% methanol is estimated to be 10 ^-10 cm ² / s or less. When the ionic conductivity was 10 ⁻² S / cm or more, the expansion was poor, and the permeability of 10 wt% methanol was 10 ⁻⁷ cm ² / s or less. In addition, the swelling resistance to water can not only significantly lower the methanol crossover, but also has the advantage that it is possible to manufacture an ion exchange membrane having a high mechanical strength and a sufficient mechanical strength with a small thickness.

The ion exchange membrane of the present invention has a form in which a polymer comprising structural units A and B 'is chemically crosslinked, and has been given ionic conductivity by sulfonation or the like, and maintains mechanical strength in a conventional physical gel form. Compared to general ion exchange membranes, the membrane has a low swelling by solvents and fuels, which significantly reduces methanol crossover, which is an obstacle to DMFC development, and exhibits excellent characteristics as an ion conductive membrane for DMFCs. The high mechanical strength is visible, which can contribute to the weight and miniaturization of existing PEMFC.

In addition, the ion-exchange membrane obtained from the present invention is a three-dimensional film-like polymer of a three-dimensional network structure that does not dissolve in any solvent and only a small amount of swelling by chemical crosslinking reaction through light irradiation using a non-fluorinated polymer material having a cost effective force It can be widely used in fuel cells such as PEMFC and DMFC having ion conductive groups through sulfonation while maintaining the shape of the gel. Furthermore, in addition to fuel cells, electrolysis, electrodialysis, diffusion dialysis, pressure dialysis, electrolyzer, It can be widely used in various electrochemical devices such as chloro-alkali separators, batteries and the like.

Claims (21)

A crosslinking point is formed by a crosslinking reaction from a structural unit A selected from the group consisting of Formula 1 and Formula 2 below, and a copolymer comprising a structural unit B selected from the group consisting of Formula 3 and Formula 4 is covalently bonded. Ion exchange membrane in the form of an irreversible chemical gel film crosslinked through. Formula 1 Formula 2 Formula 3 Formula 4 -ArR _7- In the above Chemical Formulas 1 to 4, R _1, R _2, R _3, R ₄ and R ₅ are each independently hydrogen, phenyl, C _1-4 lower alkyl, C _1-4 lower alkylene, C _1-4 lower alkynyl Nyl, nitrile or a reactor capable of independently inducing a condensation reaction, for example epoxy, cyanate, ester, halogen. R ₆ represents hydrogen or a lower alkyl group of C _1-4 , Ar represents a substituted or unsubstituted phenyl group wherein the substituent is phenyl, C _1-4 lower alkyl, C _1-4 lower alkylene or C _{1- 4} lower alkynyl, R ₇ represents —SO ₃ H, —COOH, or —P (O) (OR ₈ ) OH group, wherein R ₈ represents hydrogen or a C _1-4 lower alkyl group. The ion exchange membrane of claim 1, wherein the copolymer is selected from the group consisting of random copolymers, alternating copolymers, block copolymers, graft copolymers, and combinations thereof. The ion exchange membrane of claim 1, wherein a degree of substitution of an ion conductive group selected from the group consisting of -SO ₃ H, -COOH, and -P (O) (OR ₈ ) OH groups is 15 to 80%. The ion exchange membrane of claim 1, wherein R ₇ is —SO ₃ H. ₃ . The ion exchange membrane of claim 1, wherein the ion conductivity of the ion exchange membrane is 1.0 × 10 ⁻⁴ or more. a) preparing a polymer solution of a copolymer of structural unit A selected from the group consisting of Formula 1 and Formula 2 below and structural unit B ′ selected from the group consisting of Formula 3 and Formula 4 below; b) preparing the obtained polymer solution into a film after or without adding a crosslinking initiator; c) crosslinking the film by light irradiation or heating; And d) When the degree of substitution of the ion conductive group is less than 15%, the cross-linked film is swelled by dipping in a solvent, and then -SO ₃ H, -COOH, or -P (O) ( OR ₈ ) A process for preparing the ion exchange membrane of claim 1 comprising introducing an OH group. Formula 1 Formula 2 Formula 3 Formula 4 -ArR _7- In the above Chemical Formulas 1 to 4, R _1, R _2, R _3, R ₄ and R ₅ are each independently hydrogen, phenyl, C _1-4 lower alkyl, C _1-4 lower alkylene, C _1-4 lower alkynyl Nyl, nitrile or a reactor capable of independently inducing a condensation reaction, for example epoxy, cyanate, ester, halogen. R ₆ represents hydrogen or a lower alkyl group of C _1-4 , and Ar represents a substituted or unsubstituted phenyl group, wherein the substituent is phenyl, C _1-4 lower alkyl, C _1-4 lower alkylene, C _{1- 4} lower alkynyl, R ₇ represents hydrogen or an ionic conductive group selected from the group consisting of —SO ₃ H, —COOH and —P (O) (OR ₈ ) OH groups, wherein R ₈ represents hydrogen or C _{1 -4} lower alkyl group. The method of claim 6, wherein the copolymer is selected from the group consisting of random copolymers, alternating copolymers, block copolymers, graft copolymers, and combinations thereof. The method of claim 6, wherein the compound having structural unit A is substituted by a substituent selected from the group consisting of nitrile, epoxy, cyanate, ester, halogen or selected from ethylene, butylene, butadiene and propylene. The compound of claim 6, wherein the compound having structural unit B 'is polystyrene, poly (α-methylstyrene), poly (triphenylphosphine oxide sulfide-phenylsulfone-sulfide), poly (2-phenylsulfide-1,4 -Phenylene), poly-X (Maxdem), diphenyl poly (2,6-diphenyl-1,4-phenylene oxide, poly (bisbenzoazole-1,4-phenylene, poly (benzo (bis- Thiazole) -1,4-phenylene, poly (benzo (bis-diazole) -1,4-phenylene, polyaramid (Kevlar), polyphenylene sulfone, polysulfone, polyether sulfone, polyether-ether Sulfone, polyarylether sulfone, polyimide, poly (2,6-dimethyl 1,4-phenylene oxide, polyphenylene sulfoxide, polyphenylene sulfide, polyphenylene sulfide sulfone, polyparaphenylene, poly (phenyl Vinooxaline, polyether ketone, polyether ether ketone, polyether ketone ketone, polyether ether ketone ketone, polyether ether ketone ketone, poly Polyimide, polyphenylsulfone, poly (hexafluoroisopropylidene dianhydride / metaphenylene diamine), poly (hexafluoroisopropylidene dianhydride / diaminodiphenyl sulfone), polyvinyl sulfonic acid, poly (Hexafluoroisopropylidene dianhydride / polyaminodiphenoxybenzene, poly (pyrromeltic diimide-1,3-phenylene), poly (diphthalimide-1,3-phenylene), poly (1,4-phenylene oxide), poly (benzophenone sulfide) and poly (benzophenone sulfide phenylsulfone-sulfide) or polyvinylcarboxylic acid, poly (tripoolostyrene sulfonic acid), poly (vinyl phospho) Lactic acid), polystyrene sulfonic acid. 7. The method of claim 6, wherein said copolymer comprises at least 20% benzene rings. The method of claim 6, wherein the crosslinking initiator is benzophenone, 2,6-bis (azidobenzylidene) -4-methylcyclohexanone, 2,2-dimethoxy-2-phenylacetophenone, 1-benzoyl-1 -Hydroxycyclohexane and 2,4,6-trimethylbenzoyldiphenylphosphine oxide. The method of claim 6, wherein the film formation of step b) is achieved by evaporation or casting of a solvent. The method of claim 6, wherein the solvent of step d) is a chlorolated hydrocarbon solvent, a hydrocarbon solvent, or a mixed solvent thereof. The non-particulate irradiation or alpha particles, beta particles, high energy electrons, protons and neutrons according to claim 6, wherein the crosslinking of the film of step c) is composed of microwave, IR, UV, visible light, x-ray and gamma ray. A method accomplished by irradiation of particulates. The method according to claim 6, wherein the ion conductive group of step d) is -SO ₃ H, and the introduction of sulfone group is sulfuric acid / acetic anhydride, sulfur / trioxide / acetic acid, sulfuric acid / sulfate, SO ₃ / phosphorus Pentaoxide, SO ₃ / triethyl phosphate, SO ₃ / tris (2-ethylhexyl) phosphate, SO ₃ / acetic acid, SO ₃ / lauric acid, chlorosulfonic acid and trimethylsilylsulfonylchloride Method achieved by a sulfonating agent. The method of claim 6, wherein the solvent of step d) is a chlorolated hydrocarbon solvent, a hydrocarbon solvent or a mixed solvent thereof. The method of claim 6 wherein the method is a) preparing a polymer solution of a copolymer having structural unit A and structural unit B ', b) adding a crosslinking initiator to the obtained polymer solution and then preparing a film; c) crosslinking the film by light irradiation or crosslinking, d) When the degree of substitution of the ion conductive group is less than 30%, the cross-linked film is swelled by dipping in a solvent, and then -SO ₃ H, -COOH or -P (O) ( OR ₈ ) further introducing the OH group. An electrochemical device comprising the ion exchange membrane according to any one of claims 1 to 5. 19. The method of claim 18, wherein the electrochemical device comprises: a) a cathode portion comprising a cathode, b) an anode portion comprising an anode, and c) a cathode disposed between the cathode portion and the anode portion to act as an insulating film and an electrolyte membrane. An apparatus which is a fuel cell comprising the ion exchange membrane according to any one of claims 1 to 5. 20. The apparatus of claim 19, wherein the fuel cell is a direct methanol fuel cell using methanol as fuel. 20. The apparatus of claim 19, wherein the fuel cell is a polymer electrolyte fuel cell using hydrogen as fuel.