KR20100120519A - Polysulfone crosslinked with dicarbonyl group, method for preparing thereof, polymerelectrolyte membrane comprising the same, fuel cell employing the same - Google Patents

Abstract

PURPOSE: Polysulfone cross-linked with a dicarbonyl group, a producing method thereof, a polymer electrolyte film using thereof, and a fuel cell including thereof are provided to secure the excellent tensile strength and dimensional stability at the high temperature. CONSTITUTION: Polysulfone cross-linked with a dicarbonyl group is marked with chemical formula 1. In the chemical formula 1, Y is a single bond, -S-, -O-, or -S(=O)2-. Z is a cation exchanger, or its metal salt group selected from the group consisting a sulfonic acid group, a phosphate group, a carboxylic acid, a sulfonamide group, and a C1~C10 alkylsulfone acid group.

Description

POLYSULFONE CROSSLINKED WITH DICARBONYL GROUP, METHOD FOR PREPARING THEREOF, POLYMERELECTROLYTE MEMBRANE COMPRISING THE SAME, FUEL CELL EMPLOYING THE SAME}

The present invention relates to a polysulfone crosslinked with a dicarbonyl group capable of maintaining low water content, excellent dimensional stability, and high ion conductivity at high temperature, a method for preparing the same, an electrolyte membrane using the same, and a fuel cell employing the same.

Fuel cells, particularly solid polymer electrolyte fuel cells, have been developed in various ways since they were proposed in the 1950s for the purpose of supplying energy to spacecraft. At present, many attempts are being made to apply fuel cells in the automobile industry in addition to the power supply for spacecraft. In addition, a lot of attention has been paid to fuel cells in various industries.

First, there is a growing interest in preventing air pollution by combustion of internal combustion engines. In practice, it is very difficult to completely block all emission compounds such as nitrogen oxides, incompletely burned hydrocarbons and acidic compounds by combustion of internal combustion engines through the control of internal combustion engines' own combustion reactions.

Second, developing cars that use fuels other than fossil fuels, such as oil and coal, that are not permanent in the long run.

Representative polymer electrolyte fuel cells include a hydrogen exchange gas fuel cell (Proton Exchange Membrane Fuel Cell (PEMFC)) and a direct methanol fuel cell using liquid methanol directly supplied to the cathode as a fuel. Fuel Cell: DMFC). In these fuel cells, hydrogen and methanol supplied as fuel are almost permanent and produce water as a by-product through electrochemical reactions.

1 shows a membrane-electrode assembly of a fuel cell that generates electrical energy and generates water as a by-product.

Referring to FIG. 1, the membrane electrode assembly includes a cathode 4, an anode 5, and a polymer electrolyte membrane 1 interposed therebetween.

The fuel (2, hydrogen or methanol solution) supplied to the cathode 4 generates hydrogen ions through the catalytic reaction of the coating layer 8, as shown in the following reaction formula.

For hydrogen fuel cells:

2H ₂ → 4H ^{+ +} 4e ^-

For direct methanol fuel cells:

_{CH 3 OH + H 2 O →} CO 2 + 6H + + 6e -

The generated hydrogen ions transfer hydrogen ions 9 to the anode 5 side via the polymer electrolyte membrane 1. In addition, electrons generated by the reaction are transferred to the anode 5 side through the external circuit 6. At the anode 5, the following reduction reaction occurs with oxygen, hydrogen ions and electrons injected into the anode 5 to generate electrical energy, and water 7 is generated as a by-product:

For hydrogen fuel cells:

_{^{O 2 + 4H + + 4e -}} → 2H 2 O

For direct methanol fuel cells:

^{_{3 / 2O 2 + 6H + +}} 6e - → CO 2 + 2H 2 O

The cathode 4 and the anode 5 have a structure in which metal catalyst particles such as platinum or ruthenium are deposited on a carbon support and exhibit hydrogen ion conductivity.

Membrane electrode assembly (MEA) is composed of a very thin thickness of the millimeter unit, and is usually composed of a polymer electrolyte membrane and two electrodes attached to both sides and serving as a cathode and an anode, respectively.

In such fuel cells, the polymer electrolyte membrane plays an important role of conducting ions from the anode to the cathode. Currently, polymer electrolyte membranes for fuel cells have been widely used polymers in which cation exchange groups such as sulfonic acid groups and phosphoric acid groups are introduced.

For example, the introduction of sulfonic acid groups is a conventionally used method to impart hydrophilicity to a polymer, and may control the hydrophilicity of the polymer electrolyte membrane itself by controlling the content of sulfonic acid groups, which are hydrophilic functional groups. Thus, due to the hydrophilicity imparted to the polymer electrolyte membrane and the acidity of the sulfonic acid group itself, it serves as an electrolyte capable of transferring hydrogen ions.

However, the introduction of a cation exchanger, which is a strong acid group, acts as a disadvantage in weakening the chemical stability of the membrane. In particular, the problem of controlling the hydrophilicity in the electrolyte membrane for a fuel cell is a very important problem. If the water content is too low, the membrane may not properly transfer hydrogen ions, resulting in poor hydrogen ion conductivity. In addition, when the moisture content is too high, the mechanical properties of the membrane may be lowered due to excessive expansion of the membrane, and the membrane may be damaged or the bonding with the electrode layer may be weakened.

In particular, in a direct methanol fuel cell, a phenomenon in which methanol, which is a fuel, is passed along with water and poisons the catalyst, occurs. When the membrane has a high water content, this phenomenon becomes worse.

The most widely used method to prevent this phenomenon is to crosslink the polymer. When the polymer is crosslinked, even if the content of the cation exchanger is high, the stability is relatively increased due to the increase in the overall molecular weight, and the mechanical properties are also improved. In particular, crosslinking limits the expansion rate in the hydrated state. That is, it is possible to manufacture a polymer electrolyte membrane for a fuel cell having a low water content even at the same cation exchanger content.

Among the crosslinking methods widely used include photo-crossllinking (S. Fujiyama, J. Ishikawa, T. Omi and S. Tamai, Polymer Journal , 40 ( 2008 ), 17-24), ionic crosslinking , ZW Bai, GE Price, M. Yoonessi, SB Juhl, MF Durstock, and TD Dang, J. Membr.Sci. , 305 ( 2007 ), 69-76) and covalent crosslinng, W. Zhang, V Gogel, KA Friedrich and J. Kerres, J. Power Sources , 155 ( 2006 ), 3-12). However, these crosslinking methods are often low in crosslinking degree, and in many cases, the crosslinking method is complicated or additional catalyst is required. In the case of using such an additional catalyst, the degree of crosslinking may be lowered depending on the reactivity of the catalyst, and a crosslinking reaction may be complex as a side reaction occurs or, above all, an additional step for removing the catalyst.

For example, Zhang et al. (C. Zhang, X. Guo, J. Fang, H. Xu, M. Yuan, B. Chen, J. Power Sources , 170 ( 2007 ), 42) and Fang et al. (J. Fang, F. Zhai, X. Guo, H. Xu, K.-I. Okamoto, J. Mater. Chem ., 17 ( 2007 ), 1102 describe Friedel-Craft polymers containing sulfonic acid groups in a polymer matrix. While suggesting a method of crosslinking by the Craft reaction, it has been reported that the crosslinking has an effect on improving mechanical strength and dimensional stability to some extent.

However, the method has a problem in that the sulfonic acid group is changed to the sulfonic group as the sulfonic acid group necessary for high cation conductivity is used as the crosslinking site, and thus the sulfonic acid group, which is a cation exchange group, is rapidly reduced. In addition, there is a disadvantage in that a mixture of polyphosphoric acid or methane sulfonic acid and P ₂ O ₅ must be used as a catalyst.

It is an object of the present invention to provide polysulfones which have improved physical and chemical stability and which are crosslinked with dicarbonyl groups.

Another object of the present invention is to prepare a polysulfone crosslinked with a dicarbonyl group which can crosslink the polysulfone in a simple process without a catalyst and prevent the reduction of the cation exchange group due to the crosslinking reaction because the cation exchanger does not act as a crosslinking site. To provide.

Another object of the present invention is to provide a polymer electrolyte membrane capable of maintaining high dimensional stability and high cation conductivity at high temperature, including the polysulfone crosslinked with the dicarbonyl group.

It is another object of the present invention to provide a membrane electrode assembly having an electrolyte membrane comprising a polysulfone crosslinked with the dicarbonyl group.

Still another object of the present invention is to provide a fuel cell having improved battery performance by including the electrolyte membrane.

In order to achieve the above object, the present invention provides a polysulfone crosslinked with a dicarbonyl group of formula (I):

[Formula 1]

(In the formula 1,

Y is a single bond, -S-, -O-, or -S (= O) _2- , to which carbon is directly connected,

Z represents one type of cation exchange group or metal bases thereof selected from the group consisting of sulfonic acid group, phosphoric acid group, carbonic acid group, sulfonimide group and C ₁ -C ₁₀ alkylsulfonic acid group,

Ar is a divalent C ₅ to C ₂₄ arylene group or a divalent C ₅ to C ₂₄ heteroarylene group, which is substituted with at least one C ₁ to C ₁₀ alkyl group, alkoxy group, haloalkyl group, or haloalkoxy group or Unsubstituted, optionally they are two or more aromatic rings directly connected to each other or -O-, -S-, -C (= 0)-, -CH (OH)-, -S (= 0) ₂ -,- Si (CH ₃ ) ₂ -,-(CH ₂ ) _p- (where 1≤p≤10),-(CF ₂ ) _q- (where 1≤q≤10), -C (CH ₃ ) ₂ -,- Are covalently bonded by a functional group of C (CF ₃ ) _2- , or -C (= 0) NH-,

Ar ₁ and Ar ₂ is the same as or different from each other, and is a divalent or trivalent C ₅ to C ₂₄ arylene group or a divalent or trivalent C ₅ to C ₂₄ heteroarylene group, and these are at least one C ₁ to C ₁₀ alkyl group, Alkoxy, haloalkyl, haloalkoxy, or cyanyl groups are unsubstituted or substituted, and optionally these are two or more aromatic rings directly connected to each other, or -O-, -S-, -C (= 0)-, -CH ( OH)-, -S (= O) _2- , -Si (CH ₃ ) ₂ -,-(CH ₂ ) _p- (where 1≤p≤10),-(CF ₂ ) _q- (where 1≤q ≦ 10), —C (CH ₃ ) ₂ —, —C (CF ₃ ) ₂ —, or —C (═O) NH—, which are covalently bonded

An integer of 1 ≦ a, b ≦ 4,

An integer of 3 ≦ n ≦ 400,

An integer of 0 ≦ m ≦ 400; And

0 <z≤4 is an integer)

In addition, the present invention as shown in Scheme 1,

There is provided a method of crosslinking a polysulfone of formula (2) with a dicarboxylic acid compound of formula (3) to prepare a polysulfone crosslinked with a dicarbonyl group of formula (1):

Scheme 1

(In Scheme 1,

Y, Z, Ar, Ar ₁ , Ar ₂ , a, b, n, m and z are as defined in the above formula,

Ar ₁ 'and Ar ₂ is the same as or different from each other, and is a divalent C ₅ to C ₂₄ arylene group or C ₅ to C ₂₄ heteroarylene group, and these are at least one C ₁ to C ₁₀ alkyl group, alkoxy group, haloalkyl group, haloalkoxy Or unsubstituted or substituted with a cyan group, optionally wherein two or more aromatic rings are directly connected to each other, or -O-, -S-, -C (= 0)-, -CH (OH)-, -S (= O) _2- , -Si (CH ₃ ) ₂ -,-(CH ₂ ) _p- (where 1≤p≤10),-(CF ₂ ) _q- (where 1≤q≤10), -C (CH _{3) 2 -, -C (CF} 3) 2 - is a covalent bond by, or -C (= O) NH- in the functional group)

In another aspect, the present invention provides a polymer electrolyte membrane comprising a polysulfone crosslinked with the dicarbonyl group.

The present invention also provides a cathode; Anode; And a polymer electrolyte membrane positioned between the cathode and the anode, wherein the membrane electrode assembly comprises polysulfone crosslinked with the dicarbonyl group as a polymer electrolyte membrane.

In addition, the present invention provides a fuel cell comprising the polysulfone crosslinked with the dicarbonyl group as a polymer electrolyte membrane.

The polysulfone crosslinked with the dicarbonyl group of the present invention has high tensile strength, low water content, and has excellent dimensional stability, hydrogen ion conductivity, and methanol permeability at high temperature.

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

In order to impart hydrophilicity to hydrogen ion conductive polymers such as polysulfone, cation exchange groups such as sulfonic acid groups are introduced. However, the introduction of such a strong acid cation exchanger has disadvantages such as chemical stability weakening, catalyst poisoning phenomenon, so that a method of crosslinking polysulfone is commonly used to prevent this.

However, the conventional crosslinked polysulfone has a problem in that a cation exchange group is used as a crosslinking site so that the number of cation exchange groups essential for hydrogen ion conduction after crosslinking decreases sharply. In addition, there is a disadvantage in that a catalyst for the crosslinking reaction is required and the crosslinking reaction is complicated.

인 것을 특징으로 하는 디카보닐기로 가교된 폴리설폰을 제공한다. In order to solve this problem, in the present invention, a polysulfone which is a hydrocarbon-based polymer having a sulfone group in the backbone and some hydrogen atoms are substituted with a cation exchanger is a crosslinked polymer crosslinked with each other, and the crosslinking is a direction in which hydrogen atoms are not substituted with a cation exchanger. Between ring and crosslinking group

It provides a polysulfone crosslinked with a dicarbonyl group, characterized in that.

In the polysulfone of the present invention, the dicarbonyl group, which is a crosslinking group, strengthens the binding of the polymer chain and reduces the water content of the polymer electrolyte membrane as it limits the hydrophilic region, thereby reducing swelling. Accordingly, the polymer electrolyte membrane made of the crosslinked polysulfone has excellent dimensional stability and can maintain high ion conductivity at high temperature.

Specifically, the polysulfone crosslinked with the dicarbonyl group of the present invention is represented by the following general formula (1):

[Formula 1]

(In the formula 1,

Y is a single bond, -S-, -O-, or -S (= O) _2- , to which carbon is directly connected,

Z represents one type of cation exchange group or metal bases thereof selected from the group consisting of sulfonic acid group, phosphoric acid group, carbonic acid group, sulfonimide group and C ₁ -C ₁₀ alkylsulfonic acid group,

Ar is a divalent C ₅ to C ₂₄ arylene group or a divalent C ₅ to C ₂₄ heteroarylene group, which is substituted with at least one C ₁ to C ₁₀ alkyl group, alkoxy group, haloalkyl group, or haloalkoxy group or Unsubstituted, optionally they are two or more aromatic rings directly connected to each other or -O-, -S-, -C (= 0)-, -CH (OH)-, -S (= 0) ₂ -,- Si (CH ₃ ) ₂ -,-(CH ₂ ) _p- (where 1≤p≤10),-(CF ₂ ) _q- (where 1≤q≤10), -C (CH ₃ ) ₂ -,- Are covalently bonded by a functional group of C (CF ₃ ) _2- , or -C (= 0) NH-,

Ar ₁ and Ar ₂ is the same as or different from each other, and is a divalent or trivalent C ₅ to C ₂₄ arylene group or a divalent or trivalent C ₅ to C ₂₄ heteroarylene group, and these are at least one C ₁ to C ₁₀ alkyl group, Alkoxy, haloalkyl, haloalkoxy, or cyanyl groups are unsubstituted or substituted, and optionally these are two or more aromatic rings directly connected to each other, or -O-, -S-, -C (= 0)-, -CH ( OH)-, -S (= O) _2- , -Si (CH ₃ ) ₂ -,-(CH ₂ ) _p- (where 1≤p≤10),-(CF ₂ ) _q- (where 1≤q ≦ 10), —C (CH ₃ ) ₂ —, —C (CF ₃ ) ₂ —, or —C (═O) NH—, which are covalently bonded

An integer of 1 ≦ a, b ≦ 4,

An integer of 3 ≦ n ≦ 400,

An integer of 0 ≦ m ≦ 400; And

0 <z≤4 is an integer)

로 가교된 것이다. In the polysulfone crosslinked with the dicarbonyl group of Formula 1, the polysulfone backbone is a dicarbonyl group

It is crosslinked with.

The arylene group in Chemical Formula 1 is a substituted or unsubstituted arylene group having 5 to 24 carbon atoms, preferably a straight or branched arylene group having 6 to 12 carbon atoms. At this time, the carbon number means only the number of carbons forming the aromatic skeleton of the arylene group except for the carbon number included in the substituent. Specific examples of the arylene group include a phenylene group, tolylene group, xylylene group, biphenylene group, o -terphenylene group, naphthylene group, anthracenylene group, phenanthrenylene group, fluorene and the like. In this case, the arylene group may be substituted with an alkyl group, an alkoxy group, a haloalkyl group, a haloalkyl group atom, or a cyan group.

The heteroarylene group in Chemical Formula 1 is a substituted or unsubstituted heteroarylene group having 5 to 24 carbon atoms, preferably a heteroarylene group having 5 to 15 carbon atoms. Wherein at least one hetero atom selected from the group consisting of F, S, N, O, P and Si is contained in one or more rings. Specific examples of the heteroarylene group include [1,2,4] oxadiazole, [1,3,4] oxadiazole, [1,2,4] thiadiazole, and [1,3,4] thiadia Sol, pyrrole, imidazole, pyrazole, pyridine, pyrazine, pyrimidine, pyridazine, indolizine, isoindole, indole, indazole, purine, quinolysine, isoquinoline, quinoline, phthalazine, naphthylpyridine, Quinoxaline, quinazoline, cinnoline, pteridine, carbazole, carboline, phenanthridine, acridine, phenanthroline, isothiazole, phenazine, isoxazole, phenoxazine, phenothiazine, already Diradical such as dazolidine and imidazoline. In this case, the heteroarylene group may be substituted with an alkyl group, an alkoxy group, a haloalkyl group, a haloalkyl group, or a cyan group.

In Formula 1, an alkyl group means a straight or branched saturated hydrocarbon radical having 1 to 10 carbon atoms, preferably a straight or branched saturated hydrocarbon radical having 1 to 6 carbon atoms. For example, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, iso-amyl, hexyl, 1,2-dimethyl-propyl, 2-ethyl-hexyl and the like are possible. .

The alkoxy group in the general formula (1) is a straight or branched alkoxy group having 1 to 10 carbon atoms, preferably a straight or branched alkoxy group having 1 to 6 carbon atoms. Typically methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, sec-butoxy and tert-butoxy are possible.

The haloalkyl group in Formula 1 refers to a radical in which one or more hydrogen atoms of the alkyl group defined above are substituted with one or more halogen atoms, which are the same or different. Specific examples include trifluoromethyl, difluoromethyl, 2,2-dichloroethyl, 2-fluoroethyl, 2,2-difluoroethyl, 2,2,2-trifluoroethyl, pentafluoroethyl , 3,3-difluoropropyl, 3,3,3-trifluoropropyl, 2,2,3,3-tetrafluoropropyl, 2,2,3,3,3-pentafluoropropyl, hepta Fluoropropyl and the like.

In the formula (1) haloalkoxy group means a radical in which one or more hydrogen atoms of the alkoxy group defined above is substituted with the same or different one or more halogen atoms. For example, trifluoromethoxy, fluoromethoxy, 2-fluoroethoxy, 2,2-difluoroethyl, 2,2-difluoroethoxy, 2,2,2-trifluoroethoxy, Pentafluoroethoxy, 3-fluoropropoxy, 2,2,3,3-tetrafluoropropoxy, 2,2,3,3,3-pentafluoropropoxy, heptafluoropropoxy and the like It is possible.

In addition, n which shows the polymerization degree of the said polysulfone by this invention is an integer of 3-400, Preferably it is 5-200, More preferably, it is 10-100. M which shows the degree of polymerization of the repeating unit copolymerized with polysulfone is an integer of 0-400, Preferably it is 3-200, More preferably, it is 5-100. If n is less than the above range, the mechanical properties and chemical stability are insufficient, and on the contrary, if the n exceeds the above range, the viscosity becomes too high, which makes handling difficult. In addition, when m exceeds the above range, there is a disadvantage in that the viscosity becomes high and handling is difficult.

In Chemical Formula 1, Z represents one type of cation exchange group selected from the group consisting of a sulfonic acid group, a phosphoric acid group, a carboxylic acid group, a sulfonimide group, and a C ₁ to C ₁₀ alkylsulfonic acid group or a metal base thereof, preferably Z is Sulfonic acid groups or metal bases thereof.

이고, Ar₂은

이고, a 및 b는 2이다. Preferably, in Formula 1, Z is a sulfonic acid group or a metal base thereof, z is 1, and Ar ₁ is

And Ar ₂ is

And a and b are 2.

이고, Ar₂은

이고, a 및 b는 2이다. 상기 Y가 -S-인 경우 가수분해 및 산화 안정성이 더욱 향상될 수 있다. Preferably, in Formula 1, Y is -S- or -S (= 0) _2- , Z is a sulfonic acid group or a metal base thereof, z is 1, and Ar ₁ is

And Ar ₂ is

And a and b are 2. When Y is -S-, hydrolysis and oxidation stability may be further improved.

이고, Ar₂은

이고, a 및 b는 2이다. 상기 Ar₂가

인 경우 극성-극성 상호작용에 따른 함수율 감소와 장기운전조건에서 전극과의 접착성 향상 확보가 가능하다. Preferably, in Formula 1, Z is a sulfonic acid group or a metal base thereof, z is 1, and Ar ₁ is

And Ar ₂ is

And a and b are 2. Ar ₂ is

In this case, it is possible to reduce the moisture content due to the polar-polar interaction and to improve the adhesion with the electrode under long-term operation conditions.

이고, Ar₂은

이고, a 및 b는 2이다. 상기 Y가 -S-인 경우 가수분해 및 산화 안정성이 더욱 향상될 수 있다. 상기 Ar₂가

인 경우 극성-극성 상호작용에 따른 함수율 감소와 장기운전조건에서 전극과의 접착성 향상 확보가 가능하다. Preferably, in Formula 1, Y is -S-, Z is a sulfonic acid group or a metal base thereof, z is 1, and Ar ₁ is

And Ar ₂ is

And a and b are 2. When Y is -S-, hydrolysis and oxidation stability may be further improved. Ar ₂ is

In this case, it is possible to reduce the moisture content due to the polar-polar interaction and to improve the adhesion with the electrode under long-term operation conditions.

이고, Ar₂은

이고, a 및 b는 1이다.Preferably, in Formula 1, a sulfonic acid group or a metal base thereof, z is 1, Ar ₁ is

And Ar ₂ is

And a and b are 1.

이고, Ar₂은

이고, a 및 b는 1이다. Preferably, in Formula 1, Y is -O-, Z is a sulfonic acid group or a metal base thereof, z is 1, and Ar ₁ is

And Ar ₂ is

And a and b are 1.

Preferably, Ar is selected from those represented by the following formulae, wherein the bonding position includes all of the o- , m- , p- positions:

Where W is O, S, C (= O), CH (OH), S (= O) ₂ , Si (CH ₃ ) ₂ , (CH ₂ ) _p (where 1≤p≤10), (CF ₂ ) _q (where 1 ≦ _q ≦ 10), C (CH ₃ ) ₂ , C (CF ₃ ) ₂ , or C (═O) NH)

More preferably, Ar is selected from those represented by the following formulae, wherein the bonding position comprises all o- , m- , p- positions:

Specific examples of the polysulfone crosslinked with a dicarbonyl group according to Chemical Formula 1 include, but are not limited to:

Polysulfone 1:

Polysulfone 2:

Polysulfone 3:

Polysulfone 4:

Such polysulfone crosslinked with a dicarbonyl group of the present invention is prepared by crosslinking a polysulfone of formula 2 with a dicarboxylic acid compound of formula 3, as shown in Scheme 1 below:

Scheme 1

(In Scheme 1,

Y, Z, Ar, Ar ₁ , Ar ₂ , a, b, z, n and m are as defined in the above formula,

Ar ₁ 'and Ar ₂ is the same as or different from each other, and is a divalent C ₅ to C ₂₄ arylene group or C ₅ to C ₂₄ heteroarylene group, and these are at least one C ₁ to C ₁₀ alkyl group, alkoxy group, haloalkyl group, haloalkoxy Or unsubstituted or substituted with a cyan group, optionally wherein two or more aromatic rings are directly connected to each other, or -O-, -S-, -C (= 0)-, -CH (OH)-, -S (= O) _2- , -Si (CH ₃ ) ₂ -,-(CH ₂ ) _p- (where 1≤p≤10),-(CF ₂ ) _q- (where 1≤q≤10), -C (CH _{3) 2 -, -C (CF} 3) 2 - is a covalent bond by, or -C (= O) NH- in the functional group)

In the preparation method of the present invention, polysulfones of formula (2) are crosslinked with each other using a dicarboxylic acid compound of formula (3) as a crosslinking agent. At this time, a cation exchanger such as a sulfonic acid group present in the polysulfone acts as an acid catalyst, thereby protonating the polycarboxylic acid group at the terminal of the crosslinker. The protonated crosslinker reacts with a nucleophilic aromatic ring (Ar ₁ ) and Friedel-Craft rather than a cation exchanger.

As such, since the cation exchange group present as a functional group of the polysulfone acts as an acid catalyst, a catalyst for the crosslinking reaction is not additionally required. Thus, the crosslinking process is simple since no side reactions due to the use of catalysts and additional steps for catalyst removal are not required.

In addition, since the cation exchanger is not used as a crosslinking site, it is possible to prevent a decrease in the cation exchanger due to crosslinking.

In this case, the crosslinking reaction is preferably performed at 110 to 180 ° C. for 5 to 48 hours under vacuum. In particular, the vacuum conditions allow the water produced through the Friedel-Craft reaction to be easily dehydrated. When the reaction temperature and the reaction time is less than the above range, a sufficient crosslinked polymer may not be obtained. On the contrary, even if the reaction temperature is exceeded, the crosslinking degree does not increase any more, and in some cases, the polymer backbone may be decomposed.

The crosslinking agent of Formula 3 is added in 1 to 20% by weight based on the total weight of the reactants. If the content of the crosslinking agent is less than the above range, the effect of the crosslinking agent to be obtained cannot be obtained, and if the content of the crosslinking agent is higher than the above content, the crosslinking degree is no longer increased, and side reactions occur to seriously deteriorate the final polysulfone physical properties. There is a problem.

The preparation of the polysulfones of formula (2) is not particularly limited in the present invention, and methods commonly known in the art may be used.

For example, as shown in Scheme 2, the monomers of Formulas 4 and 5 may be obtained by polymerizing (when m is 0 in Formula 1):

Scheme 2

(In Scheme 2,

Z, Y, Ar ₁ , a, n and z are as defined above,

X is a halogen element such as F, Cl, Br or I)

In addition, as shown in Scheme 3, the monomers of Formulas 4, 5 and 6 may be obtained by polymerizing:

Scheme 3

(In Scheme 3,

Z, Y, Ar ₁ , Ar ₂ , a, b, n, m and z are as defined above,

X is a halogen element such as F, Cl, Br or I)

The polysulfone crosslinked with the dicarbonyl group of the present invention prepared as described above may be applied to a polymer membrane because of excellent physical stability and chemical stability.

Accordingly, the present invention provides a polymer membrane including polysulfone crosslinked with the dicarbonyl group of Chemical Formula 1. The polymer membrane according to the present invention can be used for various purposes such as fuel cell, electrolysis, water and non-aqueous electrodialysis and diffusion dialysis, pervaporation, gas separation, dialysis, ultrafiltration, nanofiltration or reverse osmosis process. In particular, it can be preferably used as a polymer electrolyte membrane for fuel cells.

The present invention is a cathode; Anode; And in the membrane electrode assembly comprising a polymer electrolyte membrane positioned between the cathode and the anode, it provides a membrane electrode assembly comprising a polysulfone crosslinked with the dicarbonyl group of the present invention as a polymer electrolyte membrane.

The present invention also provides a fuel cell comprising polysulfone crosslinked with a dicarbonyl group of the present invention as a polymer electrolyte membrane.

The fuel cell includes a cathode and a membrane electrode assembly in which a polymer electrolyte membrane is interposed between the anode, and is a device for generating electrical energy through an electrochemical reaction between the cathode and the anode.

In this case, as the polymer electrolyte membrane of the membrane electrode assembly, a polymer electrolyte membrane including a polysulfone crosslinked with a dicarbonyl group proposed in the present invention is used. Preferably, a hydrogen ion conductive polymer fuel cell (PEMFC) or a direct methanol fuel cell ( DMFC).

Here, the cathode and the anode are not particularly limited in the present invention, and any one known in the art may be used.

The polymer electrolyte membrane of the present invention ensures low water content and high dimensional stability, reduces methanol permeability, maintains high ion conductivity at high temperature, and improves fuel cell performance.

Hereinafter, preferred examples and comparative examples of the present invention are described. The following examples and comparative examples are described for the purpose of more clearly expressing the present invention, but the contents of the present invention are not limited to the following examples and comparative examples.

Example 1 Preparation of Crosslinked Sulfonated Poly (phenylenesulfidesulfonnitrile) 40

A crosslinked sulfonated poly (phenylenesulfidesulfonnitrile) 40 represented by Formula 7 was prepared by the following Scheme 4:

Scheme 4

1-1. material

2,6-dichlorobenzonitrile (DCBN), 4,4'-thiobisbenzenethiol (TBBT), 4,4'-oxybis (benzoic acid) was purchased from Sigma-Alrich, and 3,3'- Disulfonate-4,4'-dichlorodiphenyl sulfone (SDCDPS) was synthesized according to conventionally known methods (YT Hong, CH Lee, HS Park, KA Min, HJ Kim, SY Nam, YM Lee, J. Power Sources , 175 ( 2008 ), 724-731).

1-2. Polysulfone  synthesis

5.0082 g of 4,4'-thiobisbenzenethiol (0.0200 mol), 2.0642 g of 2,6-dichlorobenzonitrile (0.0120 mol), 3.9301 g of 3,3'-disulfonate-4,4'-dichloro Diphenyl sulfone (0.0080 mol), 3.3169 g K ₂ CO ₃ (0.0240 mol), 50 mL anhydrous NMP and 25 mL toluene were placed in a four neck round bottom flask equipped with a mechanical stirrer, Dean-Stark trap. After dehydration at 140 ° C. for 4 hours, toluene was removed. The temperature was maintained at 170 ° C. for 24 hours and then the copolymer solution was precipitated in deionized water.

FT-IR spectra were obtained using Fourier transform infrared (FT-IR, Nicolet magna IR 760 spectra ESP, WI, USA) to analyze the chemical structure of the obtained sulfonated poly (phenylenesulfidesulfonnitrile) sodium salt, NMR analysis (NMR, varian model NMR 1000) was performed. the results are as follow:

FT-IR (KBr): 2225 cm ⁻¹ (m, CN), 1320 cm ⁻¹ (s, SO ₂ ), 1,065 cm ⁻¹ (s, SO ₃ Na), 815 cm ⁻¹ (vs, S).

¹ H NMR (300 MHz, DMSO-d ₆ ): δ = 8.16 (s, 4H), 7.64-7.456 (m, 28H), 7.133 (d, 6H, J = 7.43 Hz), 6.895 (t, 3H, J = 7.70 Hz).

¹³ C NMR (600 MHz, DMSO-d ₆ ): δ = 144.58, 144.23, 142.00, 136.53, 136.24, 135.98, 135.31, 134.29, 133.42, 132.23, 132.09, 131.94, 130.73, 130.60, 128.90, 127.69, 126.04, 114.70, 114.70 , 112.64.

1-3. Bridge

The remaining salt was washed in hot water for 3 hours, vacuumed and dried at 120 ° C. for 24 hours. To obtain a crosslinked membrane, sulfonated poly (phenylenesulfidesulfon nitrile) in sulfonic acid form (sulfonation degree 40%) and 4,4'-oxybis (benzoic acid) were added in an N, N- ratio by weight ratio of 97: 3. Dissolved in dimethylacetamide (hereinafter 'DMAc') at a concentration of 10% by weight, cast on a clean glass substrate, and then heated to remove solvent for 12 hours at 45 ° C, 2 hours at 60 ° C and 6 hours at 120 ° C. It was. Crosslinking was formed by Friedel-Crafts reaction by heating under vacuum at 160 ° C. for 10 hours. The crosslinked membrane was acidified with 1M H ₂ SO ₄ for 24 hours and then washed with deionized water for 24 hours.

Example  2: Bridged Sulfonation Poly ( Phenylene sulfide sulfonitril A) 50 manufacturing

Sulfonated poly (phenylenesulfidesulfone crosslinked in the same manner as in Example 1 except that sulfonated poly (phenylenesulfidesulfonitrile) (sulfonation degree 50%) was used in Examples 1 to 3 above Nitrile) 50.

The resulting crosslinked sulfonated poly (phenylenesulfidesulfonnitrile) 50 was analyzed by ATR-FTIR. As a result, 1720, which is a characteristic band of dicarbonyl group, did not exist in the sulfonated poly (phenylenesulfidesulfonnitrile) before crosslinking. A band of cm ⁻¹ was identified.

Example 3: Preparation of Crosslinked Sulfonated Poly (phenylenesulfidesulfonnitrile) 60

Sulfonated poly (phenylenesulphidesulfonite crosslinked in the same manner as in Example 1 except that sulfonated poly (phenylenesulphidesulfonnitrile) (sulfonation degree 60%) was used in Examples 1 to 3 above Reel) 60 was obtained.

The resulting crosslinked sulfonated poly (phenylenesulfidesulfonnitrile) 60 was analyzed by ATR-FTIR. As a result, 1720, a characteristic band of the dicarbonyl group which did not exist in the sulfonated poly (phenylenesulfidesulfonnitrile) before crosslinking A band of cm ⁻¹ was identified.

Example 4: Preparation of Crosslinked Sulfonated Poly (phenylenesulfidesulfone) 40

A crosslinked sulfonated poly (phenylene sulfidesulfone) 40 represented by the following Chemical Formula 8 was prepared by the scheme 5 below:

Scheme 5

4-1. material

4,4'-dichlorodiphenyl sulfone (DCDPS), 4,4'-thiobisbenzenethiol (TBBT), 4,4'-oxybis (benzoic acid) were purchased from Sigma-Alrich, 3,3 '-Disulfonate-4,4'-dichlorodiphenyl sulfone (SDCDPS) was synthesized according to a conventionally known method (YT Hong, CH Lee, HS Park, KA Min, HJ Kim, SY Nam, YM Lee, J. Power Sources , 175 ( 2008 ), 724-731).

4-2. Polysulfone  synthesis

5.0082 g of 4,4'-thiobisbenzenethiol (0.0200 mol), 3.4459 g of 4,4'-dichlorodiphenyl sulfone (DCDPS) (0.0120 mol), 3.9301 g of 3,3'-disulfonate-4 4'-dichlorodiphenyl sulfone (0.0080 mol), 3.3169 g of K ₂ CO ₃ (0.0240 mol), 50 mL of anhydrous NMP and 25 mL of toluene are mechanically stirrer, 4-neck round bottom with Dean-Stark trap Put into flask. After dehydration at 140 ° C. for 4 hours, toluene was removed. The temperature was maintained at 175 ° C. for 24 hours and then the copolymer solution was precipitated in deionized water.

The FT-IR spectrum of the obtained sulfonated poly (phenylenesulfide sulfone) sodium salt was obtained, and NMR analysis (NMR, varian model NMR 1000) was performed. the results are as follow:

FT-IR (KBr): 1320 cm ⁻¹ (s, SO ₂ ), 1,065 cm ⁻¹ (s, SO ₃ Na), 815 cm ⁻¹ (vs, S).

¹ H NMR (300 MHz, DMSO-d ₆ ): δ = 8.19, 7.64, 7.51, 7.451, 6.895.

¹³ C NMR (600 MHz, DMSO-d ₆ ): δ = 144.58, 144.23, 144.00, 139.1, 138.1, 136.2, 135.98, 135.52, 134.29, 132.09, 131.24, 130.30, 128.30, 127.69, 126.04.

4-3. Bridge

The remaining salt was washed in hot water for 3 hours, vacuumed and dried at 120 ° C. for 24 hours. To obtain a crosslinked membrane, 10% by weight of sulfonated poly (phenylenesulfide sulfone) (sulfonation degree 40%) and 4,4'-oxybis (benzoic acid) in acid form in DMAc at a weight ratio of 97: 3. Melted and cast on a clean glass substrate and then heated to remove solvent for 12 hours at 45 ° C., 2 hours at 60 ° C., and 6 hours at 120 ° C. Crosslinking was formed by Friedel-Crafts reaction by heating under vacuum at 160 ° C. for 10 hours. The crosslinked membrane was acidified with 1M H ₂ SO ₄ for 24 hours and then washed with deionized water for 24 hours.

The resulting crosslinked sulfonated poly (phenylenesulfidesulfone) 40 was analyzed by ATR-FTIR and found to be 1720 cm ^-1 of the characteristic band of the dicarbonyl group which was not present in the sulfonated poly (phenylenesulfidesulfone) before crosslinking. The band was identified.

Example 5: Preparation of Crosslinked Sulfonated Poly (phenylenesulfidesulfone) 50

Sulfonated poly (phenylene sulfide sulfone) 50 crosslinked in the same manner as in Example 4 except that sulfonated poly (phenylene sulfide sulfone) (sulfonation degree 50%) was used in 4-3 of Example 4. Got it.

The resulting crosslinked sulfonated poly (phenylenesulfidesulfone) 50 was analyzed by ATR-FTIR and found to be 1720 cm ^-1 of the characteristic band of the dicarbonyl group which did not exist in the sulfonated poly (phenylenesulfidesulfone) before crosslinking. The band was identified.

Example 6: Preparation of Crosslinked Sulfonated Poly (phenylenesulfidesulfone) 60

The sulfonated poly (phenylene sulfide sulfone) 60 crosslinked in the same manner as in Example 4 except that sulfonated poly (phenylene sulfide sulfone) (sulfonation degree 60%) was used in 4-3 of Example 4. Got it.

The resulting crosslinked sulfonated poly (phenylenesulfidesulfone) 60 was analyzed by ATR-FTIR and found to be 1720 cm ^-1 of the characteristic band of the dicarbonyl group which did not exist in the sulfonated poly (phenylenesulfidesulfone) before crosslinking. The band was identified.

Example 7: Preparation of Crosslinked Sulfonated Poly (phenylenesulfone) 80

A crosslinked sulfonated poly (phenylenesulfone) 80 represented by the following Chemical Formula 9 was prepared by the scheme 6 above:

Scheme 6

7-1. Polysulfone synthesis

Sulfonated poly (phenylenesulfide sulfone) (sulfonation degree 80%) was synthesized in the same manner as in Example 4-2, and then oxidized as described in the literature to prepare sulfonated poly (phenylene sulfone) (M Schuster, K._D. Kreuer, HT Anderden, J. Maier, Macromolecules 40 ( 2007 ) 598-607).

20 g of sulfonated (phenylenesulfide sulfone) was dispersed in 400 ml of glacial acetic acid and 30 ml of concentrated sulfuric acid (97%). Then 26 ml of hydrogen peroxide (31%) were added slowly and the mixture was stirred at 30 ° C. for 2 days. When the color of the mixture changed from brown to colorless, it was heated at 100 ° C. for 10 minutes to remove residual peroxide. The mixture was diluted with 200 ml of glacial acetic acid and then filtered off and washed again with glacial acetic acid. To remove the remaining byproducts, the reacted polymer was purified by dialysis for 48 hours. Water was removed with a rotary evaporator and the final polymer was dried in vacuo at 50 ° C.

The FT-IR spectrum of the obtained sulfonated poly (phenylene sulfone) sodium salt was obtained. In the case of NMR analysis, since the polymer was not dissolved, NMR analysis (NMR, varian model NMR 1000) was performed. the results are as follow:

FT-IR (KBr): 1320 cm ⁻¹ (s, SO ₂ ), 1,065 cm ⁻¹ (s, SO ₃ Na).

¹ H NMR (300 MHz, DMSO-d ₆ ): δ = 8.5, 8.5, 8.24, 7.971, 7.895.

¹³ C NMR (600 MHz, DMSO-d ₆ ): δ = 149.48, 145.98, 143.7, 142.58, 139.71, 133.19, 129.30, 127.96.

7-2. Bridge

The remaining salt was washed in hot water for 3 hours, vacuumed and dried at 120 ° C. for 24 hours. In order to obtain a crosslinked membrane, sulfonated poly (phenylene sulfone) in acid form (sulfonation degree 40%) and 4,4'-oxybis (benzoic acid) were added in a concentration of 10% by weight in DMAc in a weight ratio of 97: 3. It was melted and cast on a clean glass substrate and then heated to remove solvent for 12 hours at 45 ° C., 2 hours at 60 ° C., and 6 hours at 120 ° C. Crosslinking was formed by Friedel-Crafts reaction by heating under vacuum at 160 ° C. for 10 hours. The crosslinked membrane was acidified with 1M H ₂ SO ₄ for 24 hours and then washed with deionized water for 24 hours.

The resulting crosslinked sulfonated poly (phenylenesulfone) 80 was analyzed by ATR-FTIR. As a result, a band of 1720 cm ⁻¹ , which is a characteristic band of the dicarbonyl group, did not exist in the sulfonated poly (phenylenesulfone) before crosslinking. Confirmed.

Example 8: Preparation of Crosslinked Sulfonated Poly (phenylenesulfone) 100

Sulfonated poly (phenylene sulfone) 100 was obtained in the same manner as in Example 7, except that sulfonated poly (phenylene sulfone) (sulfonation degree 100%) was used in 7-2 of Example 7.

The resulting crosslinked sulfonated poly (phenylenesulfone) 100 was analyzed by ATR-FTIR. As a result, a band of 1720 cm ⁻¹ , which is a characteristic band of the dicarbonyl group, did not exist in the sulfonated poly (phenylenesulfone) before crosslinking. Confirmed.

Example 9: Preparation of Crosslinked Sulfonated Poly (aryleneethersulfone) 40

A crosslinked sulfonated poly (arylene ethersulfone) 40 represented by the following Chemical Formula 10 was prepared as represented by Scheme 7:

Scheme 7

9-1. material

4,4'-dichlorodiphenyl sulfone (DCDPS), 4,4'-dihydroxybiphenyl (BP), 4,4'-oxybis (benzoic acid) were purchased from Sigma-Alrich, 3, 3'-disulfonate-4,4'-dichlorodiphenyl sulfone (SDCDPS) was synthesized according to a conventionally known method (YT Hong, CH Lee, HS Park, KA Min, HJ Kim, SY Nam, YM Lee, J Power Sources , 175 ( 2008 ), 724-731).

9 -2. Polysulfone synthesis

3.7242 g of 4,4'-dihydroxybiphenyl (0.0200 mol), 3.4459 g of 4,4'-dichlorodiphenyl sulfone (DCDPS) (0.0120 mol), 3.9301 g of 3,3'-disulfonate- 4,4'-dichlorodiphenyl sulfone (0.0080 mol), 3.3169 g of K ₂ CO ₃ (0.0240 mol), 50 mL of anhydrous NMP and 25 mL of toluene are mechanically stirrer, 4-neck round with Dean-Stark trap Placed in the bottom flask. After dehydration at 140 ° C. for 4 hours, toluene was removed. The temperature was maintained at 190 ° C. for 20 hours and then the copolymer solution was precipitated in deionized water. The FT-IR spectrum of the obtained sulfonated poly (arylene ethersulfone) sodium salt was obtained, and NMR analysis (NMR, varian model NMR 1000) was performed. the results are as follow:

FT-IR (KBr): 1320 cm ⁻¹ (s, SO ₂ ), 1,065 cm ⁻¹ (s, SO ₃ Na), 1234 cm ⁻¹ (s, —O—).

¹ H NMR (300 MHz, DMSO-d ₆ ): δ = 8.27, 7.9, 7.81, 7.68, 7.47, 7.1, 6.80

9-3. Bridge

The remaining salt was washed in hot water for 3 hours, vacuumed and dried at 120 ° C. for 24 hours. In order to obtain a crosslinked membrane, a sulfonated poly (arylene ether sulfone) in acid form (sulfonation degree 40%) and 4,4'-oxybis (benzoic acid) were concentrated in DMAc at a weight ratio of 97: 3 in 10% by weight of DMAc. Melted and cast on a clean glass substrate and then heated to remove solvent for 12 hours at 45 ° C., 2 hours at 60 ° C., and 6 hours at 120 ° C. Crosslinking was formed by Friedel-Crafts reaction by heating under vacuum at 160 ° C. for 10 hours. The crosslinked membrane was acidified with 1M H ₂ SO ₄ for 24 hours and then washed with deionized water for 24 hours.

The obtained crosslinked sulfonated poly (arylene ethersulfone) 40 was analyzed by ATR-FTIR. As a result, 1720 cm ^-1 of the characteristic band of the dicarbonyl group which did not exist in the sulfonated poly (arylene ethersulfone) before crosslinking was obtained. The band was identified.

Example 10 Preparation of Crosslinked Sulfonated Poly (Aryleneethersulfone) 50

Sulfonated poly (arylene ether sulfone) 50 crosslinked in the same manner as in Example 9, except that sulfonated poly (arylene ether sulfone) (sulfonation degree 50%) was used in 9-2 of Example 9. Got it.

The obtained crosslinked sulfonated poly (arylene ethersulfone) 50 was analyzed by ATR-FTIR. As a result, 1720 cm ^-1 of the characteristic band of the dicarbonyl group which did not exist in the sulfonated poly (arylene ethersulfone) before crosslinking was obtained. The band was identified.

Example 11: Preparation of Crosslinked Sulfonated Poly (aryleneethersulfone) 60

Sulfonated poly (arylene ether sulfone) 60 crosslinked in the same manner as in Example 9 except that sulfonated poly (arylene ether sulfone) (sulfonation degree 60%) was used in 9-2 of Example 9. Got it.

The resulting crosslinked sulfonated poly (arylene ethersulfone) 60 was analyzed by ATR-FTIR. As a result, 1720 cm ^-1 of the characteristic band of the dicarbonyl group which did not exist in the sulfonated poly (arylene ethersulfone) before crosslinking was obtained. The band was identified.

Comparative example  One: Sulfonation Poly ( Phenylene sulfide sulfonitril A) 40 manufacturing

The sulfonated poly (phenylenesulphidesulfonnitrile) sodium salt (40% sulfonated) obtained in Example 1 1-3 was dissolved in DMAc at a concentration of 10% by weight, cast on a clean glass substrate, and then at 45 ° C. Sulfonated poly (phenylenesulfidesulfonnitrile) 40 was prepared by heating to remove the solvent for 12 hours, 2 hours at 60 ° C., and 6 hours at 120 ° C.

Comparative Example 2: Preparation of Sulfonated Poly (phenylenesulphidesulfonnitrile) 50

Sulfonated poly (phenylenesulphidesulfonnitrile) 50 was prepared in the same manner as in Comparative Example 1 except that sulfonated poly (phenylenesulphidesulfonnitrile) sodium salt (sulfonation degree 50%) was used in Comparative Example 1. Got it.

Comparative Example 3: Preparation of Sulfonated Poly (phenylenesulphidesulfonnitrile) 60

Sulfonated poly (phenylenesulphidesulfonnitrile) 60 was prepared in the same manner as in Comparative Example 1 except that sulfonated poly (phenylenesulphidesulfonnitrile) sodium salt (sulfonation degree 60%) was used in Comparative Example 1. Got it.

Comparative Example 4: Preparation of Sulfonated Poly (phenylenesulfidesulfone) 40

The sulfonated poly (phenylene sulfidesulfone) sodium salt (40% sulfonated) obtained in Example 4-4 was dissolved in DMAc at a concentration of 10% by weight, cast on a clean glass substrate, and then 12 hours at 45 ° C. , To heat the solvent for 2 hours at 60 ° C. and 6 hours at 120 ° C. to prepare sulfonated poly (phenylenesulfidesulfone) 40.

Comparative Example 5: Preparation of Sulfonated Poly (phenylenesulphidesulphone) 50

A sulfonated poly (phenylene sulfide sulfone) 50 was obtained in the same manner as in Comparative Example 4 except that sulfonated poly (phenylene sulfide sulfone) sodium salt (sulfonation degree 50%) was used in Comparative Example 4.

Comparative Example 6: Preparation of Sulfonated Poly (phenylenesulfidesulfone) 60

A sulfonated poly (phenylene sulfide sulfone) 60 was obtained in the same manner as in Comparative Example 4 except that sulfonated poly (phenylene sulfide sulfone) sodium salt (60% sulfonation degree) was used in Comparative Example 4.

Comparative Example 7: Preparation of sulfonated poly (phenylenesulfone) 100

The sulfonated poly (phenylenesulfone) sodium salt obtained in 7-2 of Example 7 (sulfonation degree 100%) was dissolved in DMAc at a concentration of 10% by weight, cast on a clean glass substrate, and then 12 hours at 45 ° C. Sulfonated poly (phenylenesulfone) 100 was prepared by heating to remove the solvent at 60 ° C. for 2 hours and at 120 ° C. for 6 hours.

Comparative Example 8: Preparation of sulfonated poly (phenylene sulfone) 80

A sulfonated poly (phenylene sulfone) 80 was obtained in the same manner as in Comparative Example 7, except that sulfonated poly (phenylene sulfone) sodium salt (sulfonation degree 80%) was used in Comparative Example 7.

Comparative Example 9: Preparation of Sulfonated Poly (Arylene Ether Sulfone) 40

The sulfonated poly (arylene ethersulfone) sodium salt (40% sulfonated) obtained in Example 9-2 of Example 9 was dissolved in DMAc at a concentration of 10% by weight, cast on a clean glass substrate, and then 12 hours at 45 ° C. , Sulfonated poly (arylene ethersulfone) 40 was prepared by heating to remove the solvent at 60 ° C. for 2 hours and at 120 ° C. for 6 hours.

Comparative Example 10 Preparation of Sulfonated Poly (Arylene Ethersulfone) 50

A sulfonated poly (arylene ether sulfone) 50 was obtained in the same manner as in Comparative Example 9 except that sulfonated poly (arylene ether sulfone) sodium salt (sulfonation degree 50%) was used in Comparative Example 9.

Comparative Example 11: Preparation of sulfonated poly (ylene ethersulfone) 60

A sulfonated poly (arylene ether sulfone) 60 was obtained in the same manner as in Comparative Example 9 except that sulfonated poly (arylene ether sulfone) sodium salt (sulfonation degree 60%) was used in Comparative Example 9.

Experimental Example  1: Crosslinking Analysis

ATR-FTIR was taken to check whether the polysulfones prepared in Example 1 and Comparative Example 1 were crosslinked, and the results are shown in FIG. 2.

(A) is 4,4'-oxybis (benzoic acid) which is a crosslinking agent, (b) is the crosslinking sulfonated poly (phenylene sulfide sulfonitril) of the comparative example 1, (c) is an Example FT-IR spectrum for crosslinked sulfonated poly (phenylenesulfidesulfonnitrile) of 1.

Referring to FIG. 2, the sulfonated poly (phenylenesulphidesulfonnitrile) of Comparative Example 1 does not exist at 1720 cm ⁻¹ . A characteristic band of the dicarbonyl group (-CO-) is observed in the crosslinked sulfonated poly (phenylenesulphidesulfonitril) of Example 1 due to the crosslinking reaction with 4,4'-oxybis (benzoic acid), It was confirmed that the sulfonated poly (phenylene sulfide sulfonitryl) was crosslinked with each other with a dicarbonyl group.

Experimental Example 2: Physical Characteristic Analysis

The physical properties of the polysulfones obtained in Examples 1 to 11 and Comparative Examples 1 to 11 were analyzed, and are shown in Tables 1 and 2 below.

The molecular weight was measured by gel permeation chromatography (GPC) after dissolving polysulfone in DMF and lowering the viscosity to 0.05 M LiBr.

Tensile strength and elongation at break were measured using an Instron mechanical testing machine (AGS-500NJ, Shimazu) in accordance with ASTM D882.

The gel fraction was measured as the weight of the sample (W ₀ ), soaked in DMAc, stored for 48 hours, taken out, and removed DMAc for 2 hours at 120 ° C. under vacuum, and the weight (W ₁ ) was expressed as a percentage (gel fraction ( %) = (W ₁ / W ₀ ) ㅧ 100).

division Sulfonated
(mole%) Number average
Molecular Weight
(Mn, kgmol- ¹ ) Polydispersion
Indices
(PDI)
The tensile strength
(MPa) Elongation at Break
(%)
Gel fraction
(%) Example 1 - - - 63.1 184.1 67.5 Example 2 - - - 67.1 179.2 77.6 Example 3 - - - 49.1 158.2 67.9 Example 4 - - - 53.4 23.8 43.0 Example 5 - - - 58.2 22.4 41.1 Example 6 - - - 61.7 24.8 44.7 Example 7 - - - 27.4 55.4 33.9 Example 8 - - - 49.6 41.8 39.1 Example 9 - - - 67.8 12.3 48.6 Example 10 - - - 61.3 17.4 52.3 Example 11 - - - 57.8 18.9 49.1 Comparative Example 1 40 92.8 1.57 56.2 202.8 - Comparative Example 2 50 65.0 1.63 51.0 220.9 - Comparative Example 3 60 85.8 1.63 43.4 180.9 - Comparative Example 4 40 38.5 2.71 45.1 27.8 - Comparative Example 5 50 45.4 2.68 42.7 29.3 - Comparative Example 6 60 52.0 2.77 44.2 21.9 - Comparative Example 7 100 28.7 3.55 19.1 48.7 - Comparative Example 8 80 29.7 5.74 35.8 34.2 - Comparative Example 9 40 83.8 1.68 57.6 17.6 - Comparative Example 10 50 79.1 1.59 53.1 19.6 - Comparative Example 11 60 78.4 1.79 45.5 25.7 - Nafion117 Not applicable Not applicable Not applicable 30.3 270.0 Not applicable

In order for a polymer electrolyte membrane to be actually used in a fuel cell, a membrane electrode assembly (MEA) must be formed with a catalyst electrode and a gas diffusion layer. In this case, hot pressing is generally performed at a high pressure of 80 kgf / cm ² or more and a high temperature of 100 ° C. or more. In addition, since the battery is fastened at a high pressure of 60 kgf / cm ² or more after the MEA is inserted in the actual fuel cell assembly, the tensile strength of the polymer electrolyte membrane is one of very important factors in terms of practical use.

Referring to Table 1, the polysulfones of Comparative Examples 1 to 11 had a tensile strength of 43.4 to 56.2 Mpa, which was higher than that of Nafion 117. However, it can be seen that the tensile strength after crosslinking is increased to 49.1 to 67.1 Mpa. That is, the tensile strength of the polysulfone was remarkably improved through the dicarbonyl group crosslinking.

The solubility of N-methylpyrrolidone (NMP), DMAc, dimethylsulfonside (DMSO), and dimethylformamide (DMF) of the polysulfones prepared in Examples 1 to 11 and Comparative Examples 1 to 11 is shown in Table 2 below. Summarized in

division NMP DMAc DMSO DMF Example 1 Swelling Swelling Swelling Swelling Example 2 Swelling Swelling Swelling Swelling Example 3 Swelling Swelling Swelling Swelling Example 4 Swelling Swelling Swelling Swelling Example 5 Swelling Swelling Swelling Swelling Example 6 Swelling Swelling Swelling Swelling Example 7 Swelling Swelling Swelling Swelling Example 8 Swelling Swelling Swelling Swelling Example 9 Swelling Swelling Swelling Swelling Example 10 Swelling Swelling Swelling Swelling Example 11 Swelling Swelling Swelling Swelling Comparative Example 1 Dissolved Dissolved Dissolved Dissolved Comparative Example 2 Dissolved Dissolved Dissolved Dissolved Comparative Example 3 Dissolved Dissolved Dissolved Dissolved Comparative Example 4 Dissolved Dissolved Dissolved Dissolved Comparative Example 5 Dissolved Dissolved Dissolved Dissolved Comparative Example 6 Dissolved Dissolved Dissolved Dissolved Comparative Example 7 Dissolved Dissolved Dissolved Dissolved Comparative Example 8 Dissolved Dissolved Dissolved Dissolved Comparative Example 9 Dissolved Dissolved Dissolved Dissolved Comparative Example 10 Dissolved Dissolved Dissolved Dissolved Comparative Example 11 Dissolved Dissolved Dissolved Dissolved

Referring to Table 2, the polysulfones before crosslinking of Comparative Examples 1 to 11 are well dissolved in general polar organic solvents such as DMAc, NMP, DMSO, and DMF, but the polysulfones crosslinked with dicarbonyl groups of Examples 1 to 11 Because of the crosslinking, the polysulfone backbones were entangled with each other and did not dissolve in polar organic solvents.

Experimental Example 3: Chemical Characterization

The chemical properties of the polysulfones obtained in Examples 1 to 11 and Comparative Examples 1 to 11 were analyzed and are shown in Table 3 below.

1.Ion Exchange Capacity Measurement

Each of the polysulfone membranes prepared above was soaked in 0.1 M NaCl solution for 48 hours or longer to replace hydrogen ions (H ⁺ ) with sodium ions (Na ⁺ ). The substituted hydrogen ion (H ⁺ ) is titrated with 0.01 N NaOH standard solution, and the ion exchange capacity (Ion Exchange Capacity, IEC) value of the polymer membrane is calculated according to Equation 1 as the amount of NaOH used in the titration, The results are shown in Table 3 below.

[Equation 1]

IEC (meq / g) = (V _NaOH C _NaOH ) / W _dry

(Equation 1, W _dry : weight of dried thin film (g), V _NaOH : consumed NaOH standard solution (mL), C _NaOH : NaOH standard solution (M))

2. Measurement of Water Uptake and Dimensional Change

The water content measurement was performed by swelling the polysulfone membrane prepared above to reach equilibrium in ultrapure water, and then calculating moisture content and dimensional change rate according to Equations 2 and 3 below, and the results are shown in Table 3 below.

[Equation 2]

Moisture Content (%) = (W _wet -W _dry ) / W _dry ｘ 100

(Equation 2, W _dry : weight of the film before swelling (g), W _wet : weight of the film after swelling (g))

&Quot; (3) &quot;

% Change in dimension = (L _wet -L _dry ) / L _dry / 100

(Equation 2, L _dry : thickness of the film before swelling (µm), L _we : thickness of the film after swelling (µm))

3. Proton Conductivity Measurement

Hydrogen ion conductivity was measured by Equation 4 below by measuring ohmic resistance or bulk resistance by using a four-point probe AC impedance spectroscopic method, and the hydrogen ion conductivity was measured. The results are shown in Table 3 below.

&Quot; (4) &quot;

σ = L / RS

(Equation 4, σ: hydrogen ion conductivity (S / cm), R: ohmic resistance (Ω) of the polymer electrolyte, L: distance between the electrodes (cm), S: area in the electrolyte (cm 2) flowing a constant current) being)

4. E _a  Activation energy of proton conductivity

The activation energy of the hydrogen ion conductivity was calculated from the Arrhenius equation using the measured hydrogen ion conductivity, and the results are shown in Table 3 below.

5. Methanol Permeability

Methanol permeability was measured by the two chamber diffusion cell method. The polymer electrolyte membrane is swollen in ultrapure water for at least one day before measurement, and is installed between both chambers. When methanol is diffused from one chamber filled with 10 M methanol solution to the other chamber, the other chamber filled with ultrapure water, and over time from the chamber filled with methanol solution to the chamber filled with ultra pure water through the polymer electrolyte. , The amount of methanol diffused was measured by gas chromatography (GC, Shimadtzu, GC-14B, Tokyo, Japan), the results are shown in Table 3 below.

Referring to Table 3 above, the polysulfone membranes before the crosslinking of Comparative Examples 1 to 11 had significantly higher moisture content and dimensional change rate at 90 ° C. compared to the crosslinked polysulfone membranes of Examples 1 to 3 due to the high acidity.

3 is a graph showing the dimensional change rate according to the temperature of Examples 1 to 3 and Comparative Examples 2 to 3.

Referring to FIG. 3, the dimensional change at high temperature was significantly reduced after crosslinking. From this, it was found that crosslinking reduced the hydrophilic region, thereby strengthening the binding of the polymer chain, thereby reducing the water content.

Specifically, the polysulfone of Comparative Example 3 was dissolved in water at 90 ° C, but after crosslinking, the polysulfone of Example 3 was not dissolved in water with a dimensional change rate of 94%. In addition, the crosslinked polysulfone of Example 1 has a slight increase in the dimensional change rate from 80 ℃, 15% to 90 ℃, 23.3%. This value is only slightly higher than 20.5% of Nafion 117. This means that polysulfones have significantly improved dimensional stability by crosslinking.

Referring to Table 3, the polysulfone of Comparative Example 1 has a hydrogen ion conductivity of 0.233 S · cm ⁻¹ at 90 ° C., and less than 0.185 S · cm ⁻¹ of Nafion 117. high. In general, in order to manufacture a polymer electrolyte membrane having high performance, the hydrogen ion conductivity must be high. However, the moisture content and dimensional change rate of Comparative Example 1 are also very high.

The crosslinked polysulfone of Example 1 had a lower hydrogen ion conductivity than Comparative Example 1 due to a decrease in water content after crosslinking. However, the hydrogen ion conductivity at 90 ° C. of Example 1 after crosslinking was maintained at 0.223 S · cm ⁻¹ , which is higher than Nafion 117.

The moisture content and dimensional change rate of Comparative Examples 2 and 3 were too high to measure the hydrogen ion conductivity at 90 ° C. The morphology of the membrane after crosslinking was maintained during the measurement, and the amount of sulfonic acid per unit volume was high due to the decrease in moisture content.

Figure 4 is a graph showing the hydrogen ion conductivity according to the temperature of Examples 1 to 3 and Comparative Examples 2 to 3.

Referring to FIG. 4, the hydrogen ion conductivity at the low temperature of the crosslinked polysulfone film was slightly reduced compared to the polysulfone film not crosslinked, but the hydrogen ion conductivity at the high temperature was maintained high.

In the case of methanol permeability, it was extremely reduced after crosslinking, as shown in Table 3. The polysulfone membrane of Comparative Example 2 could not be measured at 90 ° C. due to excessive swelling in 5M methanol solution, but the methanol permeability after crosslinking was 45.6 × 10 ⁻⁷ cm ² · S ⁻¹ . That is, it was found that the water content lowered due to the crosslinking and the crosslinked portion act as a barrier for methanol permeation, thereby reducing the methanol permeability.

 From the above results, it was confirmed that the polysulfone reduced water content, dimensional change rate and methanol permeability after crosslinking with a dicarbonyl group. In the case of hydrogen ion conductivity, the crosslinked polysulfone decreased at 30 ° C. compared with the polysulfone before crosslinking, but the hydrogen ion conductivity of the crosslinked polysulfone at 30 ° C. was high. That is, polysulfone was able to achieve dimensional stability, improved hydrogen ion conductivity at high temperatures, and reduced methanol permeability through dicarbonyl group crosslinking.

Polysulfone crosslinked with a dicarbonyl group according to the present invention can be applied as a polymer electrolyte membrane of a fuel cell.

1 shows a schematic assembly of a fuel cell that generates water simultaneously with the generation of electrical energy.

(A) is 4,4'-oxybis (benzoic acid) which is a crosslinking agent, (b) is sulfonated poly (phenylene sulfide sulfonitryl) before crosslinking of the comparative example 1, (c) is an Example FT-IR spectrum for crosslinked sulfonated poly (phenylenesulfidesulfonnitrile) of 1.

3 is a graph showing the dimensional change rate according to the temperature of Examples 1 to 3 and Comparative Examples 2 to 3.

Figure 4 is a graph showing the hydrogen ion conductivity according to the temperature of Examples 1 to 3 and Comparative Examples 2 to 3.

Claims (18)

A polysulfone crosslinked with a dicarbonyl group of formula [Formula 1]

(In the formula 1, Y is a single bond, -S-, -O-, or -S (= O) _2- , to which carbon is directly connected, Z represents one type of cation exchange group or metal bases thereof selected from the group consisting of sulfonic acid group, phosphoric acid group, carbonic acid group, sulfonimide group and C ₁ -C ₁₀ alkylsulfonic acid group, Ar is a divalent C ₅ to C ₂₄ arylene group or a divalent C ₅ to C ₂₄ heteroarylene group, which is substituted with at least one C ₁ to C ₁₀ alkyl group, alkoxy group, haloalkyl group, or haloalkoxy group or Unsubstituted, optionally they are two or more aromatic rings directly connected to each other or -O-, -S-, -C (= 0)-, -CH (OH)-, -S (= 0) ₂ -,- Si (CH ₃ ) ₂ -,-(CH ₂ ) _p- (where 1≤p≤10),-(CF ₂ ) _q- (where 1≤q≤10), -C (CH ₃ ) ₂ -,- Are covalently bonded by a functional group of C (CF ₃ ) _2- , or -C (= 0) NH-, Ar ₁ and Ar ₂ is the same as or different from each other, and is a divalent or trivalent C ₅ to C ₂₄ arylene group or a divalent or trivalent C ₅ to C ₂₄ heteroarylene group, and these are at least one C ₁ to C ₁₀ alkyl group, Alkoxy, haloalkyl, haloalkoxy, or cyanyl groups are unsubstituted or substituted, and optionally these are two or more aromatic rings directly connected to each other, or -O-, -S-, -C (= 0)-, -CH ( OH)-, -S (= O) _2- , -Si (CH ₃ ) ₂ -,-(CH ₂ ) _p- (where 1≤p≤10),-(CF ₂ ) _q- (where 1≤q ≦ 10), —C (CH ₃ ) ₂ —, —C (CF ₃ ) ₂ —, or —C (═O) NH—, which are covalently bonded An integer of 1 ≦ a, b ≦ 4, An integer of 3 ≦ n ≦ 400, An integer of 0 ≦ m ≦ 400; And 0 <z≤4 is an integer) The method of claim 1, wherein Z is a sulfonic acid group or a metal base thereof, z is 1, and Ar ₁ is

And Ar ₂ is

And a and b are 2 polysulfone crosslinked with a dicarbonyl group. The method of claim 1, wherein Y is -S- or -S (= 0) _2- , Z is a sulfonic acid group or a metal base thereof, z is 1, and Ar ₁ is

And Ar ₂ is

And a and b are 2 polysulfone crosslinked with a dicarbonyl group. The method of claim 1, wherein Z is a sulfonic acid group or a metal base thereof, z is 1, and Ar ₁ is

And Ar ₂ is

And a and b are 2 polysulfone crosslinked with a dicarbonyl group. The method of claim 1, wherein Y is -S-, Z is a sulfonic acid group or a metal base thereof, z is 1, and Ar ₁ is

And Ar ₂ is

And a and b are 2 polysulfone crosslinked with a dicarbonyl group. The method of claim 1, wherein Z is a sulfonic acid group or a metal base thereof, z is 1, and Ar ₁ is

And Ar ₂ is

And a and b are 1, wherein the polysulfone crosslinked with a dicarbonyl group. The method of claim 1, wherein Y is -O-, Z is a sulfonic acid group or a metal base thereof, z is 1, and Ar ₁ is

And Ar ₂ is

And a and b are 1, wherein the polysulfone crosslinked with a dicarbonyl group. The polysulfone crosslinked with a dicarbonyl group according to claim 1, wherein Ar is selected from one of the following formulae:

Where W is O, S, C (= O), CH (OH), S (= O) ₂ , Si (CH ₃ ) ₂ , (CH ₂ ) _p (where 1≤p≤10), (CF ₂ ) _q (where 1 ≦ _q ≦ 10), C (CH ₃ ) ₂ , C (CF ₃ ) ₂ , or C (═O) NH) The polysulfone crosslinked with a dicarbonyl group according to claim 1, wherein Ar is selected from one of the following formulae:

As shown in Scheme 1 below, A method for preparing a polysulfone crosslinked with a dicarbonyl group represented by Chemical Formula 1 by crosslinking polysulfone represented by Chemical Formula 2 with a dicarboxylic acid compound represented by Chemical Formula 3: Scheme 1

(In Scheme 1, Y, Z, Ar, Ar ₁ , Ar ₂ , a, b, n, m and z are as defined in the above formula, Ar ₁ 'and Ar ₂ is the same as or different from each other, and is a divalent C ₅ to C ₂₄ arylene group or C ₅ to C ₂₄ heteroarylene group, and these are at least one C ₁ to C ₁₀ alkyl group, alkoxy group, haloalkyl group, haloalkoxy Or unsubstituted or substituted with a cyan group, optionally wherein two or more aromatic rings are directly connected to each other, or -O-, -S-, -C (= 0)-, -CH (OH)-, -S (= O) _2- , -Si (CH ₃ ) ₂ -,-(CH ₂ ) _p- (where 1≤p≤10),-(CF ₂ ) _q- (where 1≤q≤10), -C (CH _{3) 2 -, -C (CF} 3) 2 - is a covalent bond by, or -C (= O) NH- in the functional group) The method of claim 10, wherein the crosslinking reaction is performed at 110 to 180 ° C. for 5 to 48 hours under vacuum. The method of claim 10, wherein the crosslinking reaction is performed without a catalyst. The method of claim 10, wherein the dicarboxylic acid compound of Chemical Formula 3 is used at 1 to 20% by weight based on the total amount of the reactants. The method of claim 10, wherein Ar is selected from one of the following formulas:

Where W is O, S, C (= O), CH (OH), S (= O) ₂ , Si (CH ₃ ) ₂ , (CH ₂ ) _p (where 1≤p≤10), (CF ₂ ) _q (where 1 ≦ _q ≦ 10), C (CH ₃ ) ₂ , C (CF ₃ ) ₂ , or C (═O) NH) The method of claim 10, wherein Ar is selected from one of the following formulas:

A polymer electrolyte membrane comprising a polysulfone crosslinked with a dicarbonyl group according to any one of claims 1 to 9.  Cathode; Anode; And a polymer electrolyte membrane positioned between the cathode and the anode, wherein the polysulfone crosslinked with the dicarbonyl group according to any one of claims 1 to 9 is used as the polymer electrolyte membrane. Membrane electrode assembly. A fuel cell comprising a polysulfone crosslinked with a dicarbonyl group according to any one of claims 1 to 9 as a polymer electrolyte membrane.

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