KR101699484B1 - Preparation Method of Branched and Sulfonated Copolymer Containing Perfluorocyclobutylene Group - Google Patents

Abstract

The present invention relates to a branched sulfonated copolymer containing a perfluorocyclobutylene group, a process for producing the same, and an electrolyte membrane using the same.
The copolymer according to the present invention exhibits excellent hydrogen ion conductivity by a branched structure that facilitates hydrogen ion conduction and phase separation, and thus is useful as a polymer electrolyte membrane of a fuel cell.

Description

Preparation of Branched and Sulfonated Copolymer Containing Perfluorocyclobutylene Group Containing Perfluorocyclobutylene Group [

The present invention relates to a branched sulfonated copolymer comprising perfluorocyclobutylene groups, a process for their preparation and their use.

Fuel cells are energy conversion systems that convert chemical energy into electrical energy. Active research is underway with the need for development of alternative energy due to the explosive increase in electricity demand, high energy efficiency, and eco-friendly characteristics with less pollutant emissions.

Fuel cells are classified according to the electrolyte material used or the operating temperature. Among them, polymer electrolyte membrane fuel cells (PEMFC) can be used for small-sized combined power generation that simultaneously supplies power and heat. Compared with batteries, it has excellent energy conversion characteristics and power density characteristics, can operate at low temperature, and has many advantages such as stability against mechanical impact, and thus it is attracting attention as a power source for automobiles and electronic parts.

Such a polymer electrolyte membrane is required to have high ionic conductivity, safety against oxidation-reduction, and high mechanical strength. For example, membrane fuel cells which are currently available, there may be mentioned fluorine-based ion exchange membrane before the DuPont (Dupont)'s Nafion (Nafion ^™), Asai Chemical (Asahi Chemical)'s Asif Rex (Aciplex ^™) and the like. Such a pre-fluorinated electrolyte membrane is characterized by being divided into a main chain which is an extremely hydrophobic group and a side chain which is an extreme hydrophilic group, so that phase separation is easy and microphase separation suitable for ion conduction is well performed.

However, such a pre-fluorinated polymer electrolyte membrane has a problem of high cost as compared with excellent performance and a problem of reduction of efficiency at 80 ° C or higher. In addition, when such a membrane is used in a direct methanol fuel cell (DMFC), there is a problem of methanol crossover in which methanol is ejected from the oxidation electrode to the reduction electrode through the membrane. To solve such problems, various studies have been made to replace such perfluorinated membranes with non-fluorinated membranes or partially fluorinated membranes.

For example, U.S. Patent No. 5,602,185 discloses a process for producing a polymer electrolyte membrane by copolymerizing a partially fluorinated trifluorostyrene derivative. However, since the above-mentioned method uses a palladium catalyst in the production process, the production cost of the monomers increases, the mechanical properties are deteriorated due to the rigid structure of the polystyrene itself, and the control of the distribution, position and number of sulfonic acid groups in the polymer skeleton But also the water content of the membrane is increased as the sulfonic acid group is increased, thereby deteriorating the physical properties of the electrolyte membrane.

U.S. Patent No. 6,090,895 discloses a crosslinking process of sulfonated polymers such as sulfonated polyether ketone, sulfonated polyether sulfone, and sulfonic polystyrene. However, an effective method for appropriately processing a thin film from a crosslinked sulfonic acid polymer in large quantities has not been proposed.

On the other hand, European Patent Laid-Open Publication No. 1,113,517 A2 discloses a block-copolymer polyelectrolyte membrane having no sulfonic acid group-containing block and sulfonic acid group. At this time, the aromatic block is sulfonated using sulfuric acid, but the aliphatic polymer bond is chemically decomposed during the sulfonation process.

Also, U.S. Patent Application Publication No. 2004-186262 discloses a method for producing a multi-block copolymer polyelectrolyte membrane in which a hydrophobic block made of hydrocarbon and a hydrophilic block are alternately formed. Due to the low solubility of the multi-block copolymer, this method converts the -SO ₃ K-type copolymer into -SO ₂ Cl by using thionyl chloride to impart hydrogen ion conductivity to the polymer membrane. However, this method has a problem in that the manufacturing process is complicated, there is a problem of toxicity during the manufacturing process, and the mechanical integrity of the polymer thin film does not reach a level required when the fuel cell is driven.

Korean Patent No. 0756457 discloses an electrolyte membrane using a block copolymer containing a perfluorocyclobutane group. However, since the above method forms a block only in the main chain, unlike the existing pre-fluorine electrolyte membrane, there is a limit in that the complete phase separation of the polymer is limited.

As a result of efforts to improve the problems of the polymer used as a conventional electrolyte membrane, the present inventors have found that bis (trifluorovinyloxy) monomer having high sulfonation activity, bis (trifluorovinyloxy) monomer having low sulfonation activity, (Trifluorovinyloxy) monomer capable of imparting a branched structure can be polymerized and then sulfonated to form a branched sulfonated copolymer that is easily phase-separated, thereby having a high ionic conductivity, Ion exchange membranes, dehumidifying membranes, humidifying membranes, and the like can be used, and the present invention has been accomplished based on this finding.

It is an object of the present invention to provide a branched sulfonated copolymer having a branching structure that facilitates phase separation and hydrogen ion conduction, has excellent hydrogen ion conductivity and mechanical properties, and includes a chemically stable perfluorocyclobutylene group .

Another object of the present invention is to provide a process for producing a branched sulfonated copolymer comprising perfluorocyclobutylene group which is easy to manufacture and can control the distribution, position and number of sulfonic acid groups in a polymer skeleton will be.

Another object of the present invention is to provide a polymer electrolyte membrane having improved hydrogen ion conductivity including a branched sulfonated copolymer containing the perfluorocyclobutylene group.

It is still another object of the present invention to provide a membrane electrode assembly having an electrolyte membrane comprising the branched sulfonated copolymer containing the perfluorocyclobutylene group.

It is still another object of the present invention to provide a fuel cell having the above-described electrolyte membrane and having improved cell performance.

In order to accomplish the above object, the present invention provides a branched polyunsaturated copolymer represented by the following Formula 1:

[Chemical Formula 1]

(In the formula 1,

Wherein Q represents a 1,2-perfluorocyclobutylene group (C ₄ F ₆ );

Wherein R ₁ is comprising one or more benzene rings and an inert aromatic functional group that does not induce a chemical reaction, in which R ₁ in this case comprises the two benzene rings which each directly connected or - (CO) -, - ( SO 2 ) -, - (SO) - , - (PO) - and _{- (C (CF 3) 2} ) - is connected through any one selected from the group consisting of;

An aromatic group that the R ₂ comprises at least one benzene ring, where R ₂ is 2 if it contains two benzene rings these are connected directly to each other or _{-O-, -S-, - (CH 2} ) -, - ( _{C (CH 3) 2) -} , - (SO 2) -, - (CO) -, - (PO) -, - (Si (CH 3) 2) -, - (Si (C 6 H 5) 2) -, -NH-, -NR _a - and -R _b -, wherein R _a is an alkyl group or an aryl group of C 1 to C 25, and R _b is a group selected from the group consisting of C 1 to C 25 An alkylene group or an arylene group;

Wherein R ₃ is an aromatic functional group into which at least one SO ₃ H or SO ₃ M is introduced into the benzene ring of R ₂ , wherein M is K, Na, Li, or Mg;

로 이루어지는 군으로부터 선택되는 어느 하나를 통해 연결되며, 이때 상기 R_c는 (CH), (C(CH₃)), (CF), 또는 (C(CF₃))이고;Wherein R ₄ is an aromatic functional group containing at least one benzene ring, in which R ₄ is if they contain two benzene rings, the benzene rings or connected directly to one another, -O-, -S-, - (CH 2 ) -, - (C (CH 3) 2) -, - (SO 2) -, - (CO) -, - (PO) -, - (Si (CH 3) 2) -, - (Si (C 6 H ₅ ) ₂ ) -, -NH-, -NR _a - and -R _b -, wherein R _a is a C1 to C25 alkyl group or an aryl group, and the R _b is an alkylene group or an arylene group of C1 ~ C25, where R ₄ is 3 if it contains a benzene ring, said benzene ring being connected directly to each other or _{-O-, -S-, - (CH 2} ) -, - _{(C (CH 3) 2)} -, - (SO 2) -, - (CO) -, - (PO) -, - (Si (CH 3) 2) -, - (Si (C 6 H 5) 2 ) -, -NH-, R < _c >, and

Wherein R _c is (CH 2), (C (CH ₃ )), (CF), or (C (CF ₃ ));

Wherein _{a, b 1, b 2,} c, a ', b' 1, b '2 and c' is an integer, and wherein _{10≤ a + b 1 + b 2} + c + a '+ b' 1 + b ' ₂ + c '? 10,000)

The present invention also relates to a process for producing a compound represented by the formula (1)

S1) polymerizing a bis (trifluorovinyloxy) monomer represented by the formula 2, a bis (trifluorovinyloxy) monomer represented by the formula 3, and a tris (trilovlovinyloxy) monomer represented by the formula 4 to obtain a perfluoro Preparing a branched copolymer comprising a cyclohexobutylene group; And

S2) reacting the copolymer represented by the formula (5) with a sulfonating agent to sulfonate the branched sulfonated copolymer having the perfluorocyclobutylene group represented by the following formula (1)

[Reaction Scheme 1]

(In the above Reaction Scheme 1,

Wherein R ₁ , R ₂ , R ₃ , R ₄ , a, b ₁ , b ₂ , c, a ', b' ₁ , b ' ₂ and c'

b = b ₁ + b ₂ , b '= b' ₁ + b ' ₂ )

The present invention also provides a polymer electrolyte membrane comprising the branched sulfonated copolymer containing the perfluorocyclobutylene group.

The present invention also relates to a plasma display panel comprising a cathode; Anode; And a polymer electrolyte membrane positioned between the cathode and the anode, wherein the polymer electrolyte membrane comprises a branched sulfonated copolymer containing the perfluorocyclobutylene group as a polymer electrolyte membrane. Thereby providing a junction body.

The present invention also provides a fuel cell comprising the branched sulfonated copolymer containing the perfluorocyclobutylene group as a polymer electrolyte membrane.

The branched sulfonated copolymer containing a perfluorocyclobutylene group according to the present invention exhibits high hydrogen ion conductivity due to a branched structure that facilitates ion conduction, has excellent mechanical properties, is chemically stable Polymer membranes, polymer composite membranes, flat membranes, hollow fiber membranes, and tubular membranes, and are used in various forms such as fuel cell membranes, ion exchange membranes, dehumidification membranes, humidification membranes Film and the like.

Also, the branched sulfonated copolymer containing a perfluorocyclobutylene group in a solution or a molten state can be easily produced through the production process according to the present invention, and the distribution, position, and number of sulfonic acid groups in the polymer skeleton Can be controlled.

FIG. 1 is a graph showing the hydrogen ion conductivity of a branched sulfonated copolymer containing perfluorocyclobutylene groups prepared in Examples 1 to 3 according to the present invention. FIG.

Hereinafter, the present invention will be described in detail.

The sulfonated copolymer containing the perfluorocyclobutylene group according to the present invention has a structure in which a hydrophilic block containing a sulfonic acid group or a sulfonic acid base and a hydrophobic block containing no sulfonic acid group or a sulfonic acid base are chemically bonded alternately to each other, The block and the hydrophobic block have a branched structure. As a result, the separation of the micro-world between the hydrophilic region and the hydrophobic region is effectively formed, and thus the ionic conductivity is high.

Specifically, the branched sulfonated copolymer comprising the perfluorocyclobutylene group of the present invention is represented by the following formula (1): < EMI ID =

[Chemical Formula 1]

(In the formula 1,

Wherein Q represents a 1,2-perfluorocyclobutylene group (C ₄ F ₆ );

Wherein R ₁ is comprising one or more benzene rings and an inert aromatic functional group that does not induce a chemical reaction, in which R ₁ in this case comprises the two benzene rings which each directly connected or - (CO) -, - ( SO 2 ) -, - (SO) - , - (PO) - and _{- (C (CF 3) 2} ) - is connected through any one selected from the group consisting of;

An aromatic group that the R ₂ comprises at least one benzene ring, where R ₂ is 2 if it contains two benzene rings these are connected directly to each other or _{-O-, -S-, - (CH 2} ) -, - ( _{C (CH 3) 2) -} , - (SO 2) -, - (CO) -, - (PO) -, - (Si (CH 3) 2) -, - (Si (C 6 H 5) 2) -, -NH-, -NR _a - and -R _b -, wherein R _a is an alkyl group or an aryl group of C 1 to C 25, and R _b is a group selected from the group consisting of C 1 to C 25 An alkylene group or an arylene group;

Wherein R ₃ is an aromatic functional group into which at least one SO ₃ H or SO ₃ M is introduced into the benzene ring of R ₂ , wherein M is K, Na, Li, or Mg;

로 이루어지는 군으로부터 선택되는 어느 하나를 통해 연결되며, 이때 상기 R_c는 (CH), (C(CH₃)), (CF), 또는 (C(CF₃))이고;Wherein R ₄ is an aromatic functional group containing at least one benzene ring, in which R ₄ is if they contain two benzene rings, the benzene rings or connected directly to one another, -O-, -S-, - (CH 2 ) -, - (C (CH 3) 2) -, - (SO 2) -, - (CO) -, - (PO) -, - (Si (CH 3) 2) -, - (Si (C 6 H ₅ ) ₂ ) -, -NH-, -NR _a - and -R _b -, wherein R _a is a C1 to C25 alkyl group or an aryl group, and the R _b is an alkylene group or an arylene group of C1 ~ C25, where R ₄ is 3 if it contains a benzene ring, said benzene ring being connected directly to each other or _{-O-, -S-, - (CH 2} ) -, - _{(C (CH 3) 2)} -, - (SO 2) -, - (CO) -, - (PO) -, - (Si (CH 3) 2) -, - (Si (C 6 H 5) 2 ) -, -NH-, R < _c >, and

Wherein R _c is (CH 2), (C (CH ₃ )), (CF), or (C (CF ₃ ));

Wherein _{a, b 1, b 2,} c, a ', b' 1, b '2 and c' is an integer, and wherein _{10≤ a + b 1 + b 2} + c + a '+ b' 1 + b ' ₂ + c '? 10,000)

Preferably, R < _{1 >} is an aromatic functional group having a low sulfonation activity selected from among those represented by the following formula:

More preferably, R < ₁ > is selected from those represented by the formula:

Also preferably, R < ₂ > is an aromatic functional group having a high sulfonating activity selected from among those represented by the following formulas:

More preferably, said R < ₂ > is selected from those represented by the formula:

Wherein R < ₃ &_gt; One or more sulfonic acid groups or sulfonic acid bases are introduced into the benzene ring of the aromatic functional groups exemplified. And is preferably selected from those represented by the formula:

Also preferably, R < ₄ > is selected from those represented by the formula:

More preferably, said R < ₄ > is selected from those represented by the formula:

The copolymer according to the present invention is designed to have an appropriate molecular weight in the production step and preferably has a weight average molecular weight of 10,000 to 1,000,000, more preferably 15,000 to 610,000. If the amount is less than the above range, the mechanical properties and the chemical stability are insufficient. On the other hand, if the amount is in excess of the above range, the viscosity becomes too high, which makes handling difficult.

Specific examples of the branched sulfonated copolymers containing the perfluorocyclobutylene group according to the above formula (1) include, but are not limited to,

One)

2)

3)

Such a branched sulfonated copolymer containing a perfluorocyclobutylene group of the present invention can be obtained by reacting a bis (trifluorovinyloxy) monomer represented by the formula (2), a bis (trifluoro (Trifluorovinyloxy) monomer and a tris (trifluorovinyloxy) monomer of formula (4) to produce a branched copolymer comprising a perfluorocyclobutylene group represented by formula (5); And S2) reacting the copolymer represented by the formula (5) with a sulfonating agent to form a sulfonate.

[Reaction Scheme 1]

(In the above Reaction Scheme 1,

Wherein R ₁ , R ₂ , R ₃ , R ₄ , a, b ₁ , b ₂ , c, a ', b' ₁ , b ' ₂ and c'

b = b ₁ + b ₂ , b '= b' ₁ + b ' ₂ )

Hereinafter, the manufacturing method will be described in more detail in each step.

(Trifluorovinyloxy) monomer of the formula 2, the bis (trifluorovinyloxy) monomer of the formula 3 and the tris (trifluorovinyloxy) monomer of the formula 4 are polymerized in the step S1) The branched copolymer comprising the perfluorocyclobutylene group to be displayed is polymerized.

The monomers of formulas (2) and (3) commonly have perfluorovinyloxy groups at both ends and perfluorovinyloxy groups at the three ends of the monomer of formula (4). As a result, the perfluorovinyloxy group is cyclized to form a perfluorocyclobutylene group, and at the same time, a copolymer having a branched structure is formed.

At this time, the polymerization reaction is preferably performed in an inert gas atmosphere. The inert gas may be, for example, nitrogen or argon atmosphere.

The polymerization reaction is preferably carried out in a molten state or a solution state by heating for 30 minutes to 72 hours at a temperature range of 130 to 450 ° C. If the reaction temperature is lower than the above range, there is a problem that the cyclobutane ring-forming reaction does not occur or occurs very slowly. On the other hand, if the reaction temperature exceeds the above range, there is a problem that the copolymer is decomposed.

The polymerization reaction is carried out in an organic solvent when it is carried out in a solution state, but is not particularly limited in the present invention as long as it can dissolve reactants and products well. For example, an aprotic polar solvent such as dimethylsulfoxide (DMSO), N-methyl-2-pyrrolidone (NMP), dimethylformamide (DMF), dimethylacetamide (DMAC) (DPE), 1,3,5-trimethylbenzene and the like can be used.

Subsequently, in step S2), the copolymer represented by the formula (5) is sulfonated by reacting with the sulfonating agent.

Such sulfonation can be carried out using known methods, and there is no particular limitation as to the usable sulfonating agent as long as it can introduce -SO ₃ H into the polymer. Representatively, chlorosulfonic acid, sulfur trioxide, sulfuric acid, fuming sulfuric acid, acyl sulfate and the like are possible.

The step S2) is R ₂ with a high sulfonation active monomer in the copolymer represented by formula (5) is through a sulfonate, more than one sulfonic acid group or a sulfonic acid base is introduced into the benzene ring of R _2. As a result, hydrophobic blocks (R ₁ -containing monomers, R ₂ -containing monomers, R ₄ -containing monomers) for inducing mechanical integration degree and hydrophilic blocks (R ₃ -containing monomers) for imparting ion conductivity are alternately connected by chemical bonding To form a branch structure.

As described above, the production method according to the present invention is characterized in that monomers of the formula (2) having a low sulfonation activity, monomers of the formula (3) having a high sulfonation activity and monomers of the formula (4) do. Accordingly, by controlling the molar ratio of the monomers represented by the formula (2) to (4), it is possible to easily control the distribution and number of the sulfonic acid groups in the polymer backbone.

The copolymer of the present invention thus produced has not only a perfluorocyclobutylene group known as a chemically stable material having excellent mechanical properties, but also has a branched structure with easy phase separation, and thus has excellent hydrogen ion conductivity. In addition, the number, distribution, and position of sulfonic acid groups in the polymer skeleton can be controlled by controlling the ratio of monomers during polymerization, and characteristics of film properties due to an increase in sulfonic acid groups can be prevented. Therefore, the branched sulfonated copolymer containing the perfluorocyclobutylene group of the present invention can be applied as a polymer membrane.

Accordingly, the present invention provides a polymer membrane comprising a branched sulfonated copolymer having a perfluorocyclobutylene group represented by the general formula (1). The polymer membrane according to the present invention can be used for a fuel cell, an electrolytic solution, an aqueous and non-aqueous electrodialysis and diffusion dialysis, ion exchange, pervaporation, dehumidification, humidification, gas separation, dialysis, ultrafiltration, nanofiltration or reverse osmosis But it can be preferably used as a polymer electrolyte membrane for fuel cells.

The polymer membrane can be variously processed in the form of a polymer blend film, a polymer crosslinked film, a polymer composite film, a hollow fiber membrane, a tube film, or the like by a processing method commonly used in the technical field of the present invention.

The polymer electrolyte membrane can be produced by a conventional method in the art, except that a branched sulfonated copolymer containing a perfluorocyclobutylene group according to the present invention is used.

For example, the branched sulfonated copolymer containing the perfluorocyclobutylene group is reacted with dimethylsulfoxide (DMSO), dimethyl acrylic acid (DMAc), N-methyl-2-pyrrolidone (NMP) Amide (DMF); an aprotic polar solvent selected from the group consisting of amide (DMF); Or a polar solvent selected from the group consisting of methanol, ethanol and isopropanol; Casting the polymer solution on a support to form a film; And drying the formed film.

The drying can be carried out at a temperature ranging from 50 to 250 ° C. for 10 minutes to 48 hours under atmospheric pressure or under vacuum.

The present invention relates to a light emitting device, Anode; And a polymer electrolyte membrane positioned between the cathode and the anode, wherein the polymer electrolyte membrane comprises a branched sulfonated copolymer containing a perfluorocyclobutylene group of the present invention as a polymer electrolyte membrane Thereby providing a membrane electrode assembly.

The present invention also provides a fuel cell characterized by comprising a branched sulfonated copolymer containing a perfluorocyclobutylene 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 the anode, and generates electrical energy through an electrochemical reaction between the cathode and the anode.

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

Here, the cathode and the anode are not particularly limited in the present invention, and any of those known in the art can be used.

The polymer electrolyte membrane of the present invention ensures low moisture content and high dimensional stability, reduces methanol permeability, and improves the performance of the fuel cell by improving the hydrogen ion conductivity.

Example

Hereinafter, preferred embodiments and experimental examples of the present invention will be described. The following examples and experimental examples are provided for the purpose of more clearly expressing the present invention, but the present invention is not limited to the following examples and experimental examples.

Example 1: A branched sulfonated copolymer containing a perfluorocyclobutylene group represented by the general formula (7)

A copolymer represented by the formula (6) was polymerized through the following reaction and then sulfonated to prepare a branched sulfonated copolymer containing the perfluorocyclobutylene group represented by the formula (7).

[Chemical Formula 6]

(7)

(In formulas (6) and (7)

Wherein Q represents a 1,2-perfluorocyclobutylene group (C ₄ F ₆ )

4,4'-Bis (trifluorovinyloxy) biphenyl (4,4'-bis (trifluorovinyloxy) biphenyl) which is a monomer having high sulfonation activity and a monomer 4,4'-sulfonylbis (4'-sulfonyl-bis (trifluorvinyloxy) biphenyl) at a molar ratio of 4: 6 and capable of imparting a branch structure, 2, 3, and 5 mol% based on the total molar ratio of the two monomers, respectively, at 225 ° C. for 24 hours After heating in a nitrogen atmosphere, it was slowly cooled to room temperature.

The resulting polymer was dissolved in dimethylacetamide, slowly dropped into excess methanol to precipitate and then filtered to obtain a copolymer represented by Formula (6). In case of 5%, the gel state was formed during the reaction due to excessive amount, and it was not dissolved in the solvent any longer, indicating that the crosslinked structure was formed not in the branch structure.

The obtained three branched copolymers of the formula (6) were dissolved in dichloroethane at a concentration of 1 wt% in a nitrogen atmosphere, and the chlorosulfonic acid was slowly added dropwise with 4 moles of the biphenyl repeating unit, followed by sulfonation for 7 hours. The solvent of the mixture was removed and washed several times with distilled water to produce a branched sulfonated copolymer containing the perfluorocyclobutylene group of formula (7).

The number of the prepared copolymer average molecular weight (M _n) and weight average molecular weight if the resulting 1% was measured _{(M w) M n 75,000 g} / mol, M w 380,000 g / mol, the case of 2% M _n 93,000 g / mol, M _w 505,000 g / mol, 3% M _n 105,000 g / mol and M _w 610,000 g / mol. (PDI, M _w / M _n ) were all over 5 branches.

The polymer thus obtained was dissolved in dimethylacetamide at a concentration of 15% by weight and cast on a glass plate. The thickness of the copolymer solution on the glass plate was adjusted with a film applicator, dried in an oven at 80 캜 for one day, For 10 hours to prepare a branched sulfonated copolymer polymer membrane having a thickness of 50 to 120 탆.

Example 2: A branched sulfonated copolymer containing a perfluorocyclobutylene group represented by the formula (9)

The copolymer represented by the general formula (8) was polymerized through the following reaction and then sulfonated to prepare a branched sulfonated copolymer containing the perfluorocyclobutylene group represented by the general formula (9).

[Chemical Formula 8]

[Chemical Formula 9]

(In the formulas (8) and (9)

Wherein Q represents a 1,2-perfluorocyclobutylene group (C ₄ F ₆ )

(4,4'-Bis (2-trifluorovinyloxy) diphenyl sulfide), which is a monomer having a high sulfonation activity, and a monomer 4 having low sulfonation activity, (4,4'-bis (2-trifluorovinyloxy) benzophenone) in a molar ratio of 3: 7, and a monomer structure capable of imparting a branch structure, 1,1,1 (1,1,1-Tris- (4-trifluorovinyloxy) phenylphosphine oxide) was added in an amount of 1, 2 and 3 mol% based on the total molar ratio of the two monomers, , Heated at 225 캜 for 24 hours under a nitrogen atmosphere, and slowly cooled to room temperature.

The resulting polymer solution was slowly dropped into an excess amount of methanol to be precipitated, filtered, and then dried to obtain a copolymer. The copolymer was dissolved in dichloroethane in a concentration of 1% by weight in a nitrogen atmosphere, and then chlorosulfonic acid was slowly added dropwise to 4 molar times of the biphenyl repeating unit, followed by sulfonation for 7 hours. The solvent of the mixture was removed and washed several times with distilled water to produce a branched sulfonated copolymer containing the perfluorocyclobutylene group of formula (9).

The number of the prepared copolymer average molecular weight (M _n) and weight average molecular weight if the resulting 1% was measured _{(M w) M n 15,000 g} / mol, M w 78,000 g / mol, the case of 2% M _n 17,000 g / mol, M _{w of} 92,000 g / mol, M _{n of} 18,000 g / mol and M _{w of} 120,000 g / mol at 3%. (PDI, M _w / M _n ) were all over 5 branches.

The polymer thus obtained was dissolved in dimethylacetamide at a concentration of 15% by weight and cast on a glass plate. The thickness of the copolymer solution on the glass plate was adjusted with a film applicator, dried in an oven at 80 캜 for one day, For 10 hours to prepare a branched sulfonated copolymer polymer membrane having a thickness of 50 to 120 탆.

Example 3: A branched sulfonated copolymer containing a perfluorocyclobutylene group represented by the formula (11)

The copolymer represented by the formula (10) was polymerized through the following reaction and then sulfonated to prepare a branched sulfonated copolymer containing the perfluorocyclobutylene group represented by the formula (11).

[Chemical formula 10]

(11)

(In formulas (10) and (11)

Wherein Q represents a 1,2-perfluorocyclobutylene group (C ₄ F ₆ )

Bis (4-trifluorovinyloxyphenyl) propane) which is a monomer having high sulfonation activity and 1,4-bis (4-trifluorovinyloxyphenyl) Bis (trifluorovinyloxy) tetrafluorobenzene) at a molar ratio of 4: 6 and a branch structure capable of imparting 1,3,5-tris- (trifluoromethyl) tetrafluorobenzene (1,3,5-Tris- (trifluorovinyloxy) benzene) was heated at 225 DEG C for 24 hours under a nitrogen atmosphere at a molar ratio of 1, 2 and 3 mol% based on the total molar ratio of the two monomers, Lt; / RTI >

The resulting polymer solution was slowly dropped into an excess amount of methanol to be precipitated, filtered, and then dried to obtain a copolymer. The copolymer was dissolved in dichloroethane in a concentration of 1 wt% in a nitrogen atmosphere, and 4 molar equivalents of acetyl sulfate (acetic anhydride / concentrated sulfuric acid, 1.5 mol / 1 mol) was added to the repeating unit of diphenyl sulfide. Lt; / RTI > for 7 hours. The solvent of the mixture was removed and washed several times with distilled water to prepare a branched sulfonated copolymer of formula (11).

The number of the prepared copolymer average molecular weight (M _n) and weight average molecular weight if the resulting 1% was measured _{(M w) M n 20,000 g} / mol, M w 105,000 g / mol, the case of 2% M _n 19,000 g / mol, if the _{M w 104,000 g / mol, 3} % showed a _{M n 24,000 g / mol, M} w 147,000 g / mol. (PDI, M _w / M _n ) were all over 5 branches.

The polymer thus obtained was dissolved in dimethylacetamide at a concentration of 15% by weight and cast on a glass plate. The thickness of the copolymer solution on the glass plate was adjusted with a film applicator, dried in an oven at 80 캜 for one day, For 10 hours to prepare a polymer membrane having a thickness of 50 to 120 탆.

Experimental Example 1: Measurement of hydrogen ion conductivity

The hydrogen ion conductivity of the polymer membranes prepared by adjusting the molar ratio of the monomers conferring the branch structure in the branched sulfonated copolymers prepared in Examples 1 to 3 to 3% was measured by a potentiostatic two-probe method . As a comparative example, Nafion 115, which has been used as a conventional polymer membrane, was used.

A carbon paper electrode of 1 × 1 cm ² and 1.5 × 1.5 cm ² was placed on both sides of the specimen with an area of 2 × 2 cm ² at a constant pressure and a 5 mV AC voltage was applied to both ends of the electrode A frequency of MHz to 100 Hz was applied. Impedance was obtained through AC currents across the electrodes, and the hydrogen ion conductivity of each polymer membrane was measured using the same. The results are shown in Table 1 and FIG.

Temperature (℃) Hydrogen ion conductivity (S / cm) Example 1 Example 2 Example 3 Nafion 115 30 0.0890 0.0720 0.0590 0.0650 40 0.0960 0.0760 0.0670 0.0730 50 0.1070 0.0820 0.0790 0.0860 60 0.1180 0.1000 0.0890 0.0900 70 0.1340 0.1040 0.0910 0.0930 80 0.1470 0.1130 0.0990 0.0960 90 0.1590 0.1310 0.1120 0.1200 100 0.1690 0.1370 0.1290 0.1100

As shown in Table 1 and FIG. 1, the polymer membranes prepared in Examples 1 (), 2 () and 3 () according to the present invention were Nafion 115 ), It is understood that hydrogen ion conductivity is equivalent or even superior. The branched sulfonated copolymer containing the perfluorocyclobutylene group represented by the formula (1) according to the present invention can be effectively used as an electrolyte membrane for a fuel cell membrane or an ion exchange membrane, which requires excellent hydrogen ion conductivity Able to know.

Experimental Example 2: Measurement of dimensional change rate and methanol permeability

The dimensional change and the methanol permeability of the polymer membranes prepared by adjusting the molar ratio of the monomers conferring the branch structure to the branch structure in the branched sulfonated copolymers prepared in Examples 1 to 3 were measured and the results are shown in Table 2 below Respectively.

1. Measurement of Dimensional Change

The polymer membrane prepared above was swollen to the equilibrium state with ultrapure water, and then the dimensional change ratio was calculated according to the following equation (1). The results are shown in Table 2 below.

[Equation 1]

Dimensional change ratio (%) = (L _wet - L _dry ) / L _dry x 100

(In the above formula (1), L _dry : thickness of pre-swelling membrane (占 퐉), L _we : thickness of swelled membrane (占 퐉)

2. Methanol permeability

Methanol permeability was measured by two chamber diffusion cell method. Before the measurement, the polymer electrolyte membrane is swollen in ultrapure water for at least one day and then placed between both chambers. For the measurement, one of the chambers is filled with 10 M methanol solution, the other chamber is filled with ultrapure water, and the methanol is diffused from the chamber filled with the methanol solution through the polymer electrolyte to the chamber filled with ultra- , And the amount of diffused methanol was measured by gas chromatography (GC, Shimadzu, GC-14B, Tokyo, Japan). The results are shown in Table 2 below.

division Dimensional change ratio (%) Methanol permeability (cm ² / S) Example 1 8 3.1 × 10 ^-7 Example 2 9 2.5 × 10 ^-7 Example 3 7 1.4 × 10 ^-7 Nafion 115 10 9.7 × 10 ^-7

Referring to Table 2, it can be seen that the electrolyte membrane according to the present invention has a very low dimensional change rate and low methanol permeability. This indicates that the electrolyte membrane of the present invention has an effective separation of the American world by the branched structure and the methanol permeability is reduced.

Claims (16)

delete delete delete delete delete delete As shown in Scheme 1 below,
S1) polymerizing a bis (trifluorovinyloxy) monomer represented by the formula 2, a bis (trifluorovinyloxy) monomer represented by the formula 3, and a tris (trilovlovinyloxy) monomer represented by the formula 4 to obtain a perfluoro Preparing a branched copolymer comprising a cyclohexobutylene group; And
S2) reacting the copolymer represented by the formula (5) with a sulfonating agent to sulfonate the copolymer,
The tris (trifluorovinyloxy) monomer of Formula 4 is used in an amount of less than 5 mole% based on the total molar ratio of the bis (trifluorovinyloxy) monomer of Formula 2 and the bis (trifluorovinyloxy) monomer of Formula 3 , A process for producing a branched sulfonated copolymer of a branched sulfonated copolymer comprising a perfluorocyclobutylene group represented by the following formula (1) and having a polymer dispersion index (Mw / Mn) of more than 5:
[Reaction Scheme 1]

(In the above Reaction Scheme 1,
Wherein Q represents a 1,2-perfluorocyclobutylene group (C ₄ F ₆ );
Wherein R ₁ is comprising one or more benzene rings and an inert aromatic functional group that does not induce a chemical reaction, in which R ₁ in this case comprises the two benzene rings which each directly connected or - (CO) -, - ( SO 2 ) -, - (SO) - , - (PO) - and _{- (C (CF 3) 2} ) - is connected through any one selected from the group consisting of;
An aromatic group that the R ₂ comprises at least one benzene ring, where R ₂ is 2 if it contains two benzene rings these are connected directly to each other or _{-O-, -S-, - (CH 2} ) -, - ( _{C (CH 3) 2) -} , - (SO 2) -, - (CO) -, - (PO) -, - (Si (CH 3) 2) -, - (Si (C 6 H 5) 2) -, -NH-, -NR _a - and -R _b -, wherein R _a is an alkyl group or an aryl group of C 1 to C 25, and R _b is a group selected from the group consisting of C 1 to C 25 An alkylene group or an arylene group;
Wherein R ₃ is an aromatic functional group into which at least one SO ₃ H or SO ₃ M is introduced into the benzene ring of R ₂ , wherein M is K, Na, Li, or Mg;
Wherein R ₄ is an aromatic functional group containing at least one benzene ring, in which R ₄ is if they contain two benzene rings, the benzene rings or connected directly to one another, -O-, -S-, - (CH 2 ) -, - (C (CH 3) 2) -, - (SO 2) -, - (CO) -, - (PO) -, - (Si (CH 3) 2) -, - (Si (C 6 H ₅ ) ₂ ) -, -NH-, -NR _a - and -R _b -, wherein R _a is a C1 to C25 alkyl group or an aryl group, and the R _b is an alkylene group or an arylene group of C1 ~ C25, where R ₄ is 3 if it contains a benzene ring, said benzene ring being connected directly to each other or _{-O-, -S-, - (CH 2} ) -, - _{(C (CH 3) 2)} -, - (SO 2) -, - (CO) -, - (PO) -, - (Si (CH 3) 2) -, - (Si (C 6 H 5) 2 ) -, -NH-, R < _c >, and

Wherein R _c is (CH 2), (C (CH ₃ )), (CF), or (C (CF ₃ ));
Wherein _{a, b 1, b 2,} c, a ', b' 1, b '2 and c' is an integer, and wherein _{10≤ a + b 1 + b 2} + c + a '+ b' 1 + b ' ₂ + c '? 10,000,
b = b ₁ + b ₂ , b '= b' ₁ + b ' ₂ ) 8. The method according to claim 7, wherein step (S1) is performed in an inert gas atmosphere. The method according to claim 7, wherein the step S1) is carried out in a molten state or a solution state by heating for 30 minutes to 72 hours at a temperature range of 130 to 450 ° C. 8. The method of claim 7, wherein said step S1) is one aprotic polar solvent selected from the group consisting of dimethylsulfoxide, N-methyl-2-pyrrolidone, dimethylformamide and dimethylacetamide; Or an organic solvent selected from the group consisting of diphenyl ether and 1,3,5-trimethylbenzene. 8. The method according to claim 7, wherein the sulfonating agent in step S2) is one selected from the group consisting of chlorosulfonic acid, sulfur trioxide, sulfuric acid, fuming sulfuric acid, and acyl sulfate. 8. The process according to claim 7, wherein R < ₁ > is selected from aromatic functional groups having low sulfonation activity represented by the following general formulas (12) to (16)

8. The process according to claim 7, wherein R < ₂ > is selected from aromatic functional groups having high sulfone activity represented by the following formulas (17) to (28)

8. The process according to claim 7, wherein R < ₄ > is selected from the following formulas (29) to (36)

The method according to claim 7, wherein the copolymer has a weight average molecular weight of 10,000 to 1,000,000. 8. The process according to claim 7, wherein the copolymer is selected from the following formulas (37) to (39):
One)

37
2)

38
3)

39
(In the above formulas (37) to (39)
Wherein Q represents a 1,2-perfluorocyclobutylene group (C ₄ F ₆ )

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