KR20190028845A - poly(phenylene oxide) mediated anion-exchange membranes with comb-shaped structure and preparation method thereof - Google Patents

Abstract

The present invention relates to a polyphenylene oxide-based polymer having a comb structure, an anion exchange membrane for a fuel cell including the same, and a manufacturing method thereof and, more specifically, to a technique which manufactures a thin film with a poly (phenylene oxide) polymer with a comb structure introduced to a hydrophobic portion to increase water content to apply the thin film to an anion exchange membrane for a fuel cell. The present invention introduces a long alkyl group of a comb structure to a hydrophobic portion in a main chain of a poly (phenylene oxide) polymer instead of a hydrophilic conduction group (hydrophilic portion) of a polymer to exhibit excellent ionic conductivity at high and low temperatures without an increase in IEC, provide stable mechanical properties due to low dimensional changes in comparison to water content, and markedly improve alkali stability. Therefore, the present invention can be commercialized as an anion exchange membrane for a fuel cell.

Description

TECHNICAL FIELD [0001] The present invention relates to an anion exchange membrane comprising a polyphenylene oxide polymer having a comb structure, and an anion exchange membrane comprising a poly (phenylene oxide)

The present invention relates to a polyphenylene oxide-based polymer having a comb structure, an anion exchange membrane for a fuel cell comprising the same, and a process for producing the same. More particularly, the present invention relates to a polyphenylene oxide polymer having a comb- Oxide) polymer and applying the thin film to an anion exchange membrane for fuel cells.

The anion exchange membrane has a lower ionic conductivity than the cation exchange membrane (proton exchange membrane) and has a problem in that its chemical stability is lowered under high temperature alkali conditions. Various studies have been conducted to solve such problems.

Anion exchange membranes are known to be activated by the ion conduction mechanisms of the grotthuss mechanism and the vehicle mechanism, and water is an important mediator of the hydroxide ion (OH-) conduction in this process. That is, when the water content of the anion exchange membrane is increased, dissociation between the conductive group and the hydroxide ion is facilitated. This leads to an increase in the amount of hydroxide ion that ultimately diffuses, thereby improving ionic conductivity and improving stability to alkali.

A common method for increasing the water content in anion exchange membranes is to improve the IEC, the unit of ionic conductance (meq) per weight of polymer (g). However, extreme (very high silver) IEC increases the properties of the membrane, and in extreme cases, even the morphology of the membrane can not be maintained.

Therefore, the present inventor has made efforts to increase the water content only without increasing the IEC. As a result, the inventors of the present invention have found that a new structure of a poly (phenylene oxide) polymer having a comb chain long chain group introduced into the hydrophobic polymer main chain .

Patent Document 1: Korean Patent Publication No. 10-2017-0032876

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a poly (phenyl (meth) acrylate) having a comb structure in a hydrophobic part, which has improved water content and hydroxide ion conductivity and has excellent alkali stability, The present invention also provides an anion exchange membrane for a fuel cell based on a polymer thin film and a method of manufacturing the same.

In order to accomplish the above object, the present invention provides an anion exchange membrane for a fuel cell comprising a poly (phenylene oxide) polymer having a repeating unit represented by the following general formula (I).

<Formula I>

In the above formula (I)

Wherein R &lt; ₁ &gt; is any one selected from a linear or branched alkyl group having 6 to 20 carbon atoms,

R ₃ is a quaternary ammonium group of - (R ₁₀ ) N ⁺ (R ₁₁ R ₁₂ R ₁₃ )

Wherein R ₂ , R _4, R ₅ , R ₆ , R ₇ , R ₈ and R ₉ are the same or different from each other and selected from the group consisting of hydrogen, straight or branched alkyl groups having 1 to 6 carbon atoms,

R ₁₀ , R _11, R ₁₂ , and R ₁₃ are the same or different from each other and selected from the group consisting of hydrogen, a linear or branched alkyl group having 1 to 6 carbon atoms,

X, y, and z are each an arbitrary repeating unit, and x, y, and z are mole ratios in the repeating unit, 0.01? X? 0.4, 0.1? Y? 0.5, x + y + z = Or z is not zero.

R ₁ , R ₂ , R _3, R _4, R ₅ , R ₆ , R ₇ , R ₈ , and R ₉ are the same as each other, And an alkyl group having 1 to 4 carbon atoms.

In Formula (I), R ₅ is hydrogen, and R ₁₀ , R _11, R ₁₂ , and R ₁₃ may be straight chain alkyl groups having 1 to 4 carbon atoms.

In Formula (I), x may be 0.03 to 0.11, and y may be 0.3 to 0.4.

In the above formula (I), x may be 0.11 and y may be 0.37.

The anion exchange membrane for a fuel cell may have a relative humidity of 95 to 100% and a hydroxide ion conductivity of 39 to 110 mS / cm at 20 to 100 ° C.

The present invention provides a separator for a battery comprising the anion exchange membrane for a fuel cell.

The present invention provides a fuel cell including the battery separator.

The present invention relates to a process for the preparation of a compound represented by the general formula (I), which comprises: (I) adding a compound having an anion-exchange group to a polymer solution obtained by dissolving a chloromethylated poly (phenylene oxide) polymer having a repeating unit represented by the following general formula To obtain a poly (phenylene oxide) polymer; And

(II) a step of forming a poly (phenylene oxide) polymer thin film having a repeating unit represented by the general formula (I) obtained in the step (I); and a process for producing an anion exchange membrane for a fuel cell.

&Lt; Formula (II)

(Wherein R &_lt; ₁ &_gt; R ₂ , R _4, R ₅ , R ₆ , R ₇ , R ₈ , R ₉ and x, y and z are as defined in formula (I)

In Formula (II), X is any one selected from the group consisting of a single bond and an alkyl group having 1 to 4 carbon atoms.

The chloromethylated poly (phenylene oxide) polymer having the repeating unit represented by the above formula (II) is obtained by a) reacting a poly (phenylene oxide) polymer with aluminum chloride and lauryl chloride to prepare an acrylated poly (phenylene oxide) ;

b) reducing the acrylated poly (phenylene oxide) polymer of step a) to obtain a reduced poly (phenylene oxide) polymer having a repeating unit represented by the following formula (III); And

c) reacting the reduced poly (phenylene oxide) polymer of step b) with zinc chloride and chloromethyl methyl ether.

&Lt; Formula (III)

(In the above formula (III), R ₁₄ is any one selected from a linear or branched alkyl group having 6 to 20 carbon atoms, R ₁₅ , R _16, R ₁₇ , R ₁₈ and R ₁₉ are the same or different from each other and selected from the group consisting of hydrogen, a linear or branched alkyl group having 1 to 6 carbon atoms, And o and p are the mole fractions in the repeating units, 0.0? O? 0.9, 0.1? P? 0.9, o + p = 1.

The compound having an anion-exchange group may be quaternary ammonium.

The mixing weight ratio of the chloromethylated poly (phenylene oxide) polymer having the repeating unit represented by the formula (II) in the step (I) and the compound having an anion-exchange group may be 1: 0.1 to 1.

The present invention relates to a method for producing a poly (phenylene oxide) polymer by introducing a long alkyl group of comb structure into a hydrophobic portion in a main chain of a poly (phenylene oxide) polymer that is not a hydrophilic electroconductor (hydrophilic portion) It shows conductivity, stability of mechanical properties is low due to low dimensional change compared to water content, and alkali stability is remarkably improved, which can be commercialized as an anion exchange membrane for fuel cells.

1 is a ¹ H-NMR graph of a poly (phenylene oxide) polymer according to Synthesis Examples 2 to 5. 1B is a ¹ H NMR spectrum of a Racyl-PPO polymer of Formula 3, and FIG. 1C is a C ₁₁ Y ₃₇ PPO-Cl polymer of Formula 4. FIG. 1A is a ¹ H NMR spectrum of acyl- and the ¹ H NMR spectrum, Figure 1d is a ¹ H NMR spectrum of ₁₁ C Y ₃₇ QA-PPO polymer of formula (5).
2 is a ¹ H NMR spectrum of poly (phenylene oxide) polymer (PPO), acyl-PPO polymer of formula (II), Racyl-PPO polymer of formula (III) and C ₁₁ Y ₃₇ PPO-Cl polymer of formula (IV).
3A shows the results of measurement of each of poly (phenylene oxide) polymer (PPO), acyl-PPO polymer of formula 2, Racyl-PPO polymer of formula 3 and C ₁₁ Y ₃₇ PPO-Cl polymer of formula 4 by gel permeation chromatography Fig.
Figure 3b is a comparative example 1 of the C ₀ Y ₃₇ of the PPO-Cl Polymer Synthesis Example 7 C ₃ Y ₃₇ of the PPO-Cl Polymer Synthesis Example 8 C ₇ Y ₃₇ of the PPO-Cl Polymer and Preparation Example 9 C ₁₁ Y ₃₇ PPO-Cl &lt; / RTI &gt; polymers were measured by gel permeation chromatography.
4 shows changes in hydroxide conductivity at 100% relative humidity (RH) at 20 ° C, 40 ° C, 60 ° C and 80 ° C in the anion exchange membranes for fuel cells according to Examples 1 to 3 and Comparative Example 3 Fig.
5 is a DSC graph showing DSC characteristics according to heating conditions of C _n Y _m PPO-Cl prepared according to Synthesis Examples 7 to 9 and Comparative Example 1. Fig.
6 is a graph showing changes in stress (MPa) according to elongation percentage (%) of an anion exchange membrane for a fuel cell manufactured according to Examples 1 to 3 and Comparative Example 3. Fig.
7 is a graph showing the results of measuring the conductivity loss (%) of the hydroxide ion conductivity after immersing the anion exchange membranes of Examples 1 to 3 and Comparative Example 3 in a 1M KOH solution under the condition of 80 ° C.

Hereinafter, an anion exchange membrane for a fuel cell and a method for producing the same according to the present invention will be described in detail with reference to examples and accompanying drawings.

The present invention provides an anion exchange membrane for a fuel cell comprising a poly (phenylene oxide) polymer having a repeating unit represented by the following formula (I).

<Formula I>

In the above formula (I)

Wherein R &lt; ₁ &gt; is any one selected from a linear or branched alkyl group having 6 to 20 carbon atoms,

R ₃ is a quaternary ammonium group of - (R ₁₀ ) N ⁺ (R ₁₁ R ₁₂ R ₁₃ )

Wherein R ₂ , R _4, R ₅ , R ₆ , R ₇ , R ₈ and R ₉ are the same or different from each other and selected from the group consisting of hydrogen, straight or branched alkyl groups having 1 to 6 carbon atoms,

R ₁₀ , R _11, R ₁₂ , and R ₁₃ are the same or different from each other and selected from the group consisting of hydrogen, a linear or branched alkyl group having 1 to 6 carbon atoms,

X, y, and z are each an arbitrary repeating unit, and x, y, and z are mole ratios in the repeating unit, 0.01? X? 0.4, 0.1? Y? 0.5, x + y + z = Or z is not zero.

Also, in the above formula (I), the arrangement of each phenylene component having the subscript x, y, z may be arbitrary or one block.

The poly (phenylene oxide) polymer has a poly (phenylene oxide) repeating unit as a backbone, at least one conductive functional group (preferably an anion-exchange functional group) in its side chain, Having a long alkyl group and having the structure of the repeating unit defined in the above formula (I), and having excellent chemical and thermal stability.

In particular, the poly (phenylene oxide) polymer is one which in the formula Ⅰ R ₁ is selected from the group of straight-chain or branched having 6 to 20 carbon atoms and, R ₃ is ^{_{- (R 10) N + (}} R 11 R 12 R ₁₃ ), which is a quaternary ammonium group introduced into the polymer based on poly (phenylene oxide), in which the complex structure of a long alkyl chain is not a hydrophilic part (anion exchanger) but a hydrophobic part without anion exchanger . From extensive studies of the properties of anion-exchange membranes, including their polymer forms and properties, IEC may increase if long alkyl groups of the comb structure are introduced into the hydrophilic moiety (anion exchanger) or only anion exchangers are introduced without long alkyl groups There may arise a problem that alkali stability and mechanical safety and hydroxide ion conductivity property are lowered at high temperature.

The poly (phenylene oxide) polymer having the repeating unit represented by the formula (I) may have a number average molecular weight (M _n ) of 10,000 to 1,000,000 or a weight average molecular weight (M _w ) of 10,000 to 10,000,000. When the number average molecular weight or the weight average molecular weight is less than 10,000, the prepared anion exchange membrane tends to become sticky, and when the number average molecular weight or the weight average molecular weight exceeds 1,000,000 or 10,000,000, the solubility of the polymer decreases in the solvent . In some cases, the anion exchange membrane formed by forming the polymer may have a problem that the glass transition temperature of the anion exchange membrane is reduced or the solubility in the solvent is weakened.

Specifically, poly (phenylene oxide) having a repeating unit represented by the formula Ⅰ polymer in Formula Ⅰ, R ₁ is any one selected from straight-chain alkyl group having a carbon number of 10 to 15, wherein R _2, R _4, R ₅ , R ₆ , R ₇ , R ₈ , and R ₉ are the same as each other and are more preferably selected from straight chain alkyl groups having 1 to 4 carbon atoms. Further, in Formula I, R ₅ is hydrogen , And more preferably R ₁₀ , R _11, R ₁₂ and R ₁₃ are straight-chain alkyl groups having 1 to 4 carbon atoms.

In the anion exchange membrane for a fuel cell of the present invention, the poly (phenylene oxide) polymer having a repeating unit represented by the above-mentioned formula (I) is preferably a polymer having a repeating unit represented by the general formula (I) in order to have a more stable hydroxyl ion conductivity, a water content and an alkali stability, , X is from 0.03 to 0.11, and y is from 0.3 to 0.4, the long alkyl group is introduced at a ratio of the proper amount bound to the side chain to weaken the interaction between the main chains of the polymer to have an additional free volume , It can be seen that not only is it possible to contain a relatively large amount of water but also excellent hydroxide ion conductivity can be obtained at a high temperature and a low temperature, the dimensional change is lower than the increased water content, and the alkali stability is remarkably improved. Most preferably, x is 0.11 and y is 0.37, the hydroxide ion conductivity, water content and alkali stability can be improved beyond a significant range over conventional poly (ethylene oxide) polymers introduced with anion exchangers without an increase in IEC Because.

The poly (phenylene oxide) polymer represented by the formula (I) of the present invention can be used for an anion exchange membrane of a fuel cell by improving the mechanical properties and chemical stability by crosslinking the polymer skeleton, and its thickness is 40 to 50 Mu m.

Therefore, in the present invention, the thickness of the anion exchange membrane for fuel cells obtained from the poly (phenylene oxide) polymer having the repeating unit represented by the above formula (I), wherein n is 0.03 to 0.11, m is 0.37 and z is 0.52 to 0.6, To 50 mu m, it is more preferable because an anion exchange membrane can be optimally formed at the time of application of a fuel cell, and the structural stability becomes very high. At this time, if the thickness of the anion exchange membrane is less than 40 탆, it is difficult to withstand a high operating pressure, and if the thickness exceeds 50 탆, resistance to hydroxide ion transfer may be problematic. Furthermore, since the degree of condensation between polymer chains can be controlled and the ion exchange capacity can be maximized, it can be applied to anion exchange membranes for fuel cells in addition to excellent chemical and thermal stability.

Therefore, the anion exchange membrane for a fuel cell manufactured by the combination of the above-described components has an ion exchange capacity of 0.28 meg / g lower than that of the conventional poly (phenylene oxide) polymer introduced only with an anion exchanger, However, it is characterized by a water content of 10 to 12% higher and a hydroxyl ion conductivity of 8 to 17 mS / cm and a higher 39 to 110 mS / cm. Further, it has excellent chemical and thermal stability against alkali compounds, Not only the exchange performance is excellent but also it is possible to form a thin film with low cost and high efficiency by a particularly simple and environmentally friendly heat treatment process. In order to simultaneously satisfy these characteristics, it is most preferable to have all of the conditions described above.

[Formula 1]

Wherein V _{0 NaOH} and V _{x NaOH} are the volumes of NaOH consumed in the titration under the absence of each thin film or thin film, C _NaOH is the molar concentration of NaOH titrated by standard oxalic acid solution, W _dry is the weight of the dried film. The concrete contents are described in an experimental example (FIG. 4 and Table 1) to be described later, and will not be described.

In other words, the anion exchange membrane according to the present invention increases the IEC or the alkyl group to improve the morphology by increasing the IEC or the water content in order to increase the conductivity and the moisture content. On the other hand, Was introduced into a hydrophobic region having no conductive group and not a hydrophilic region having an ionic conductor such as ammonium to improve water content, conductivity and alkali stability without increasing IEC, thereby remarkably reducing the occurrence of negative effects or side effects Respectively.

In the present invention, the structure of the poly (phenylene oxide) polymer having the repeating unit represented by the above-mentioned formula (I) is preferably a poly (phenylene oxide) polymer having a carbon number of 6 or more By introducing an alkyl side chain, a poly (phenylene oxide) polymer in which the benzyl position is substituted with an acrylic group is obtained, the ketone group is reduced to hydrogen by using triethylsilane and trifluoroacetic acid, and then anion exchanger is introduced Is prepared by adding a catalyst (ZnCl ₂ ) and a monomer (CMME) to chloromethylation to selectively introduce a chloromethyl group into another benzyl group and reacting with a compound having an anion-exchange group.

In addition, the benzyl position of the poly (ethylene oxide) polymer is replaced by an acrylic group to form the synthesized acrylated poly (ethylene oxide) intermediate, followed by reduction, chloromethylation, and then adding a compound having an anion- The present invention provides a process for producing an anion exchange membrane for a fuel cell comprising the following steps.

(I) A polymer having a repeating unit represented by the following formula (II), in which a chloromethylated poly (phenylene oxide) polymer is dissolved in an organic solvent, is added to a polymer solution having a repeating unit represented by the formula Obtaining a poly (phenylene oxide) polymer; And

(II) forming a poly (phenylene oxide) polymer thin film having a repeating unit represented by the formula (I) obtained in the step (I).

The poly (phenylene oxide) polymer according to the present invention is generally limited in its practical use in an anion-exchange membrane alkaline fuel cell (AEMFC) due to its low stability under alkaline (high pH) conditions, - ion conductivity can not be achieved due to the low electrochemical mobility of - ions. In order to overcome such a problem, conventionally, only a direction for improving IEC has been proposed, such as introduction of an anion exchanger or substitution of a hydrophilic functional group in an anion exchanger. As described above, although the ionic conductivity is improved when the IEC is improved, the physical properties of the membrane are considerably deteriorated to adversely affect fuel cell driving, the membrane can not be maintained in shape, and the use thereof is limited at high temperatures Respectively.

Accordingly, the present invention provides a poly (phenylene oxide) -based polymer which can solve the problems of conventional poly (phenylene oxide) polymers and can be used as an anion exchange membrane having water content, hydroxide ion conductivity and alkali stability simultaneously without increasing IEC .

First, a compound having an anion-exchange group is added to a polymer solution obtained by dissolving a chloromethylated poly (phenylene oxide) polymer having a repeating unit represented by the following formula (II) in an organic solvent and reacted to obtain a polymer having a repeating unit To obtain a poly (phenylene oxide) polymer.

&Lt; Formula (II)

(Wherein R &_lt; ₁ &_gt; _{R 2, R 4, R 5} , R 6, R 7, R 8, R 9 and x, y, z have the same meanings as defined in formula Ⅰ, in Formula Ⅱ X is a single bond, (CH _{2) q} (1? Q? 4).

The compound having the anion-exchange group was quaternary ammonium, and the mixing weight ratio of the chloromethylated poly (phenylene oxide) polymer having the repeating unit represented by the formula (II) to the compound having an anion-exchange group was 1: 0.1 1 &lt; / RTI &gt;

The step (I) may be carried out with stirring at 10 to 100 ° C for 10 to 50 hours.

Subsequently, an anion exchange membrane for a fuel cell, which is an object of the present invention, is prepared by forming a poly (phenylene oxide) polymer thin film having a repeating unit represented by the formula (I) obtained in step (II).

In this case, the step (II) may be carried out by reacting a poly (phenylene oxide) polymer having a repeating unit represented by the formula (I) with a solvent such as N-methylpyrrolidone (NMP) at 50 to 70 ° C for 10 to 30 hours Followed by a primary heat treatment and a secondary heat treatment at 60 to 100 ° C for 1 to 5 hours to form a thin film.

The method according to the present invention can reduce the amount of polymer used in comparison with a commonly used non-solvent induced phase separation (NIPS) or thermally induced phase separation (TIPS) Because the process itself is simple and short, it has advantages in its manufacturing cost.

The chloromethylated poly (phenylene oxide) polymer having the repeating unit represented by the above formula (II) may be prepared by the following steps.

a) synthesizing an acrylated poly (phenylene oxide) polymer by reacting a poly (phenylene oxide) polymer with aluminum chloride and lauryl chloride;

b) reducing the acrylated poly (phenylene oxide) polymer of step a) to obtain a reduced poly (phenylene oxide) polymer having a repeating unit represented by the following formula (III); And

c) reacting the reduced poly (phenylene oxide) polymer of step b) with zinc chloride and chloromethyl methyl ether;

&Lt; Formula (III)

(In the above formula (III), R ₁₄ is any one selected from a linear or branched alkyl group having 6 to 20 carbon atoms,

remind R ₁₅ , R _16, R ₁₇ , R ₁₈ , and R ₁₉ are the same or different from each other and selected from the group consisting of hydrogen, a linear or branched alkyl group having 1 to 6 carbon atoms,

O and p are arbitrary repeating units, and o and p are mole fractions in the repeating unit, respectively, 0.0? O? 0.9, 0.1? P? 0.9, o + p = 1.

That is, in order to prepare a chloromethylated poly (phenylene oxide) polymer having a repeating unit represented by the above-mentioned formula (II), a) a poly (phenylene oxide) polymer is reacted with aluminum chloride and lauryl chloride to prepare an acrylated Thereby synthesizing a poly (phenylene oxide) polymer.

At this time, the poly (phenylene oxide) polymer, aluminum chloride and lauryl chloride may be mixed in a molar ratio of 5 to 10: 1: 1, preferably 8: 9: 1: 1. The acrylated poly (phenylene oxide) polymer prepared by mixing and reacting at the above-mentioned molar ratio has an acrylation ratio of 1 to 15%.

The step a) may be carried out by stirring at room temperature for 1 to 10 hours.

Thereafter, b) the acrylated poly (phenylene oxide) polymer of step a) is reduced to synthesize a reduced poly (phenylene oxide) polymer having the repeating unit represented by the above formula (III).

At this time, triethylsilane and trifluoroacetic acid are added to the acrylated poly (phenylene oxide) polymer, and the step is preferably performed at 50 to 150 ° C for 10 to 40 hours.

Between the step b) and the step c), the reaction solution obtained from the step b) may be titrated to a neutral pH using a KOH solution.

C) reacting the reduced poly (phenylene oxide) polymer of step b) with zinc chloride and chloromethyl methyl ether to obtain a chloromethylated poly (phenylene oxide) polymer having a repeating unit represented by the above formula (II) .

The mixing weight ratio of the reduced poly (phenylene oxide) polymer, zinc chloride, and chloromethyl methyl ether in step b) is preferably 0.5 to 1.5: 0.05: 0.75. If the chloromethylated poly (phenylene oxide) polymer having the repeating unit represented by the above-mentioned formula (II) has a chloromethylation ratio of 10 to 50% when mixed and reacted at the above-mentioned weight ratio and is produced.

The poly (phenylene oxide) polymer having the repeating unit represented by the above-mentioned formula (I) is subjected to the above-mentioned series of processes, and its detailed synthesis method and analysis result are described in detail in the following embodiments.

Hereinafter, embodiments according to the present invention will be described in detail with reference to the accompanying drawings.

The materials used in the synthesis examples and examples according to the present invention are as follows.

(2,6-dimethyl-1,4-phenylene oxide) having a molecular weight of 21,000 g / mol and PDI 2.37, zinc chloride; ZnCl _2, 98%), Lau reel lauroyl chloride, hydrochloride (in> 98%), acetic acid (trifluoroacetic acid trifluoroacetate,> 99%), triethylsilane (triethylsilane,> 98%) was purchased from TCI Respectively.

Chromomethyl methyl ether (CMME, technical grade), 6-bromohexanoyl chloride (97%), aluminum chloride (99.99%), chlorobenzene (99.5% 1,2-dichloroethane (DCE, anhydrous), and trimethylamine (NMP, 99%) were purchased from Sigma-Aldrich. N-methyl-2-pyrrolidone (NMP, 99%) was purchased from Daejung and used. All compounds used commercially available sources unless otherwise noted. All experiments were carried out using distilled water.

[Synthesis Examples 1 to 3] Acylation of poly (2,6-dimethyl-1,4-phenylene oxide) (acyl-PPO: )

<Reaction Scheme 1>

The process for acrylating poly (2,6-dimethyl-1,4-phenylene) oxide (hereinafter also referred to as PPO) with an alkenyl group having 11 carbon atoms is as follows. First, a 500 ml two-necked flask equipped with a magnetic stirrer, a condenser and a nitrogen inlet was prepared. The prepared flask was charged with 6.0 g (50 mmol) of PPO (poly (2,6-dimethyl-1,4-phenylene) oxide) dissolved in 100 ml of 1,2 dichloroethane, And then cooled at room temperature. And then the mixed solution was prepared by addition of aluminum chloride _{(AlCl 3) (0.80 g,} 6 m㏖) and Lau reel chloride (1.31 g, 6 m㏖). The mixture was stirred at room temperature for 4 hours to react, and methanol (1000 ml) was added to precipitate. The precipitate was washed three times and filtered to remove byproducts and then dried at 80 DEG C under vacuum for 24 hours to obtain an acrylic poly (phenylene oxide) polymer represented by Formula 2 of white solid fiber Were synthesized and recovered (yield: 90%). In addition, the acrylation rates of the acrylated poly (phenylene oxide) polymers of Synthesis Examples 1, 2 and 3 were 3%, 7%, and 11%, respectively, and they were named acyl-PPO.

(2)

(Wherein n = 0.03, m = 0.97, n = 0.07, m = 0.93 in the above formula 2 and n = 3 in the above formula 3 prepared in Synthesis Example 3, = 0.11, m = 0.89)

It was confirmed by ¹ H-NMR data that the acrylated poly (phenylene oxide) polymer represented by Formula 2 was synthesized from Synthesis Examples 1 to 3 as follows.

δ _H (400 MHz, CDCl ₃ ) 6.50-6.32 (18H, br signal, Ar H ₁ ), 6.04-5.96 (1H, br signal Ar H ₂ ), 2.95-2.82 _{­ - C H 2), 2.24-1.89 (} 58H, br signal, ArC H 3), 1.75-1.60 (3H, br signal, Ar-CH 2 -C H 2), 1.40-1.09 (15H, br signal, CH 2 - CH ₂ --CH ₂ ), 0.90-0.72 (3H, brsignal, CH ₂ - CH ₃ )

[Synthesis Examples 4 to 6] Reduction of an acrylated poly (phenylene oxide) polymer (Racyl-PPO)

<Reaction Scheme 2>

The procedure for preparing Racyl-PPO is as follows. Acyl-PPO (DS = 3%, 7%, 11%) (5 g) prepared from Synthesis Examples 1 to 3 was dissolved in 200 ml of 1,2-dichloroethane (DCE). Thereto, 150 ml of trifluoroacetic acid (TFA) and 18 ml of triethylsilane were added, and the mixture was stirred at 100 캜 for 24 hours with stirring. After completion of the reaction, the reaction solution was titrated with 1 M KOH solution until neutral pH was reached, and methanol (1000 ml) was added to precipitate. The precipitate was washed three times, filtered to remove by-products, and then dried in vacuo at 80 캜 for 24 hours to obtain a white fiber of poly (phenyl (Yield: 82%, reduction ratio: 87%) was synthesized and recovered. This was named Racyl-PPO.

(3)

(Wherein n = 0.03, m = 0.97, n = 0.07, m = 0.93 in the above formula 3 and n = 0.93 in the above formula 3 prepared in Synthesis Example 5, = 0.11, m = 0.89)

It was confirmed by the ¹ H-NMR data that the poly (phenylene oxide) polymer having the reduced acryl group introduced thereinto synthesized from Synthesis Examples 4 to 6 was synthesized as follows.

_{δ H (400MHz, CDCl 3)} 6.55-6.37 (18H, br signal, Ar H 1), 6.03-5.96 (1H, br signal, Ar H 2), 2.86-2.73 (2H, br signal, Ar-C H 2 _{- CH 2), 2.27-1.87 (57H} , br signal, Ar-C H 3), 1.68-1.50 (3H, br signal, Ar-CH 2 -C H 2), 1.48-1.17 (15H, br signal, CH ₂ - CH ₂ -CH ₂ ), 0.91-0.78 (3H, brsignal, CH ₂ -CH ₃ )

[Synthesis Examples 7 to 9] Chloromethylation of Racyl-PPO (C _n Y _m PPO-Cl)

<Reaction Scheme 3>

C _n Y _{m The} process for preparing PPO-Cl is as follows. Racyl-PPO (DS = 3%, 7%, 11%) (3 g, 2.16 mmol) prepared from Synthesis Examples 4 to 6 was dissolved in 45 ml of chlorobenzene. To this was added zinc chloride (150 mg, 5 wt%) and chloromethyl methyl ether (CMME, 2.26 g), and the mixture was reacted at 50 캜 for 3 hours with stirring. After completion of the reaction, the reaction solution was precipitated by adding methanol (500 mL). The precipitate was washed three times, filtered to remove by-products, and then dried in vacuo at 80 ° C for 24 hours to synthesize a chloromethylated Racyl-PPO polymer represented by Formula 4 of white solid fiber (Yield 96%, degree of chloromethylation (m) 37%). This was named C _n Y _m PPO-Cl. In order to emphasize the relationship between the names of the polymers prepared from the respective synthesis examples and the corresponding formulas, the subscripts in each repeating unit were applied equally, and in the notation of C _n Y _m PPO-Cl, Respectively. Specifically, the polymer prepared in Synthesis Example 7 is denoted as C ₃ Y ₃₇ PPO-Cl, the polymer prepared in Synthesis Example 8 is denoted as C ₇ Y ₃₇ PPO-Cl, and the polymer prepared in Synthesis Example 9 is denoted as C ₁₁ Y ₃₇ PPO-Cl. &Lt; / RTI &gt;

&Lt; Formula 4 >

(Wherein n = 0.03, m = 0.37, r = 0.6, n = 0.07, m = 0.37, r = 0.56 in Synthetic Example 8, Synthetic Example 9 (N = 0.11, m = 0.37, r = 0.52)

It was confirmed by ¹ H-NMR data that the C _n Y _m PPO-Cl polymer represented by the general formula (4) was synthesized from Synthesis Examples 7 to 9 as follows.

_{δ H (400MHz, CDCl 3)} , 6.67-6.37 (10H, br signal, Ar H 1), 6.14-5.92 (5H, br signal, Ar H 2), 6.59-6.32 (14H, br signal, Ar H), 5.06-4.79 (7H, br signal, Ar-C H _{2 ­­} -Cl), 2.99-2.68 (3H, brsignal , Ar-C H 2 - CH 2), 2.47-1.85 (52H, brsignal, Ar-C H 3), 1.67-1.48 (3H, br signal, Ar-CH 2 _{-C H 2), 1.48-1.15 (15H} , br signal, CH 2 - CH 2 -CH 2), 0.92-0.77 (3H, brsignal, CH 2 - CH 3)

[Synthesis Examples 10 to 12] Synthesis of functionalized C _n Y _m Synthesis of PPO-Cl Polymer (C _n Y _m PPO-Cl-QA)

<Reaction Scheme 4>

Functionalized C ₁₁ Y ₃₇ PPO-Cl polymer synthesis is carried out through the following procedure. C ₁₁ Y ₃₇ PPO-Cl (DC = 37%) (3 g, 1.91 mmol) prepared in Synthetic Example 3 was dissolved in 15 ml of N-methyl-2-pyrrolidone Lt; / RTI &gt; Trimethylamine (TMA, 45 wt%) (1.97 g, 15 mmol) was added thereto to prepare a mixed solution. The mixed solution was stirred at 40 캜 for 48 hours to prepare a reaction solution, to which ethyl acetate (250 ml) was added. The resulting precipitate was washed with ethyl acetate three times, filtered to remove byproducts, and then dried in vacuo at 80 ^° C for 24 hours to obtain a white solid powder of the functionalized C ₁₁ Y ₃₇ PPO- Cl polymer was synthesized and recovered (yield: 91%). This was named C ₁₁ Y ₃₇ PPO-QA.

&Lt; Formula 5 >

(Wherein, n is 0.11, m is 0.37, and r is 1- (n + m) in the chemical formula 5 prepared in Synthesis Example 4)

It was confirmed by ¹ H-NMR data that the C ₁₁ Y ₃₇ PPO-QA polymer represented by the formula (2) was synthesized as described below.

_{δ H (400MHz, DMSO-d} 6), 6.66-6.38 (12H, br signal, Ar H 1), 6.34-6.11 (4H, br signal, Ar H 2), 5.04-4.60 (7H, br signal, Ar CH _{2), 3.31-3.04 (21H, br} signal, N CH 3 _­­ ), 2.38-1.75 (50H, brsignal, Ar CH3), 1.66-1.45 (3H, br signal, Ar-CH 2 - CH 2), 1.40-1.08 (15H, br signal, CH 2 - CH 2 -CH 2) , 0.85-0.69 (3H, brsignal, CH 2 - CH 3)

[Comparative Example 1] A chloromethylated poly (phenylene oxide) polymer (C ₀ Y ₃₇ PPO-Cl)

<Reaction Scheme 5>

Except that the poly (phenylene oxide) polymer represented by Formula 1 was used in place of the Acyl-PPO polymer of Synthesis Examples 1 to 3, and the same procedure as in Synthesis Example 7 was carried out to obtain chloromethylated Poly (phenylene oxide) polymer (C ₀ Y ₃₇ PPO-Cl) (poly (phenylene oxide) polymer without long alkyl chain introduced).

(6)

(Wherein m is 0.37 and r is 0.63 in the formula (6) prepared in Comparative Example 1)

[Comparative Example 2] A functionalized poly (phenylene oxide) polymer (C ₀ Y ₃₇ PPO-QA)

<Reaction Scheme 6>

C ₀ Y ₃₇ PPO-QA was prepared in the same manner as in Synthesis Example 10, except that the C ₀ Y ₃₇ PPO-Cl polymer of Comparative Example 1 was used.

&Lt; Formula 7 >

(Wherein, in Formula 7 prepared from Comparative Example 2, m is 0.37 and r is 0.63)

[Examples 1 to 3] Production of anion exchange membrane for fuel cell

The poly (phenylene oxide) polymers having different alkyl groups obtained from Synthesis Examples 10 to 12 were dissolved in N-methyl-2-pyrrolidone (NMP) to a concentration of 5 wt% to prepare a polymer solution, And then applied on a Petri dish having a diameter of 11 cm to form a thin film. The thin film was subjected to a first heat treatment at 60 ° C. for 24 hours and a second heat treatment at 80 ° C. for 4 hours under vacuum to have a crosslinked structure, thereby preparing various functional group-containing poly (phenylene oxide) polymer thin films having a crosslinked structure. The prepared thin film was immersed in deionized water and separated from the Petri dish. The separated thin films were stored in deionized water for 24 hours before analyzing properties such as mechanical properties.

[Comparative Example 3] Production of anion exchange membrane for fuel cell

Anion exchange membranes were prepared in the same manner as in Example 1, except that C ₀ Y ₃₇ PPO-QA prepared in Comparative Example 2 was used instead of C ₃ Y ₃₇ PPO-QA obtained in Synthesis Example 10.

Figure 1a is a ¹ H NMR spectrum of the acyl-PPO polymer of formula (2), Fig. 1b is a ¹ H NMR spectrum of Racyl-PPO polymer of formula (3), Figure 1c is of formula 4 C ₁₁ Y ₃₇ PPO-Cl in the polymer ¹ the H NMR spectrum, Figure 1d is a ¹ H NMR spectrum of ₁₁ C Y ₃₇ QA-PPO polymer of formula (5). ¹ H NMR spectra were obtained using an Agilent 400-MR (400 MHz) instrument using d ₆ -DMSO or CDCl ₃ as a reference.

As shown in FIG. 1, the structure of a poly (phenylene oxide) polymer having different alkyl groups is analyzed. 1A, the acyl-PPO polymer prepared in Synthesis Example 1 was prepared by introducing an acrylic monomer having a carbon number of 12 carbon atoms into a hydrophobic part of a poly (phenylene oxide) through a friedel-crafts acrylation reaction. ^As a result of the structural analysis by ¹ H NMR, it was found that 6.46 ppm peak representing hydrogen of the benzylic group of poly (phenylene oxide) (Formula 1) was 6.07 ppm by mass of acyl-PPO polymer (Formula 2) . Also, in FIG. 1A, peaks were observed at about 2.94 ppm indicating the hydrogen of the ketone group of the acrylic monomer, and characteristic peaks showing alkyl groups between 0.9 and 1.7 ppm were observed. From these results, it can be seen that acyl-PPO polymer of formula (2) was synthesized from PPO polymer of formula (1) through synthesis examples 1 to 3.

Further, the acylation ratio of acyl-PPO (Formula 2) is the sum of hydrogen of H ₇ (6.46 ppm) in benzylic acid and H ₆ (6.07 ppm) of benzylic acid substituted with acrylic group, or hydrogen H ₄ (2.08 ppm) and H ₅ (2.94 ppm), which is the hydrogen of the acrylic group, were 3, 7, and 11%, respectively.

The acrylic groups introduced into the main chain of the synthesized polymer were reduced with hydrogen using triethylsilane and trifluoroacetic acid to prepare Racyl-PPO polymers through Synthesis Examples 4 to 6, respectively. Specifically, in FIG. 1B, H ₆ (6.07 ppm), which is a benzylic hydrogen substituted with an acrylic group, was removed from the Racyl-PPO polymer of Chemical Formula 3 and shifted to 5.99 ppm, hydrogen H ₅ (2.94 ppm) A new benzylic hydrogen, H ₅ (2.80 ppm), appeared, indicating the reduction of the acyl-PPO polymer. However, no change in the integration site of the alkyl sites and no segregation was observed.

C _n Y _m PPO-CI prepared in Synthesis Examples 7 to 9 in FIG. 1C was chloromethylated. The benzene hydrogen H ₇ -digit peak in the poly (phenylene oxide) polymer at about 6.46 ppm had a peak near 6.07 ppm Benzene hydrogen moved to the H ₈ position, and a hydrogen H ₆ -digit peak showing a chloromethyl group was clearly observed near 4.92 ppm. This indicates that a portion of the benzene hydrogen residue in the poly (phenylene oxide) polymer was substituted with a chloromethyl group during the synthesis.

1D is a schematic diagram of the C _n Y _m PPO-Cl-QA (5) prepared from Synthesis Examples 10 to 12, _{wherein an} ammonium functional group enabling the conduction of OH ^- is introduced into the poly (phenylene oxide) , Each C _n Y _m PPO-CI polymer was reacted with TMA. The hydrogen H ₆ -digit peak showing the chloromethyl group disappeared at about 4.92 ppm, and the hydrogen H ₅ -digit peak of the benzyltrimethylammonium appeared at around 3.18 ppm, indicating that the chloromethyl group was completely converted to the quaternary ammonium group.

2 is a ¹ H NMR spectrum of poly (phenylene oxide) polymer (PPO), acyl-PPO polymer of formula (II), Racyl-PPO polymer of formula (III) and C ₁₁ Y ₃₇ PPO-Cl polymer of formula (IV). As shown in FIG. 2, in the acyl-PPO polymer of Formula 2, a peak corresponding to the vibration mode of C═O of the ketone group at 1700 cm ^-1 was observed. However, in the Racyl-PPO polymer of Formula 3 Not observed.

Thus, it was confirmed through synthesis example 4-6 that 3, 7, 11% acrylic groups were all reduced in the acyl-PPO polymer of formula (2).

3A shows the results of measurement of each of poly (phenylene oxide) polymer (PPO), acyl-PPO polymer of formula 2, Racyl-PPO polymer of formula 3 and C ₁₁ Y ₃₇ PPO-Cl polymer of formula 4 by gel permeation chromatography Fig.

As shown in Figure 3a it was confirmed that the poly (phenylene oxide) hayeoteum the M _n and M _w of the general formula (2) of the acyl-PPO polymer both increase as compared to the polymer (PPO). However, no additional crosslinking or degradation was observed.

Similarly, the M _n and M _w of the Racyl-PPO polymer of formula (3) were slightly lower than those of the acyl-PPO polymer of formula (2), suggesting that oxygen was reduced in the acrylic group.

Finally, the molecular weights (M _n and M _w ) of the Racyl-PPO polymer of formula (3) and the C ₁₁ Y ₃₇ PPO-Cl polymer of formula (4) were compared and it was confirmed that M _n , M _w and PDI increased sharply. It is believed that this is due to the side reaction that occurs during the chloromethylation reaction and is due to the crosslinking due to the radical generation of the benzyl chloride site.

Figure 3b is a comparative example 1 of the C ₀ Y ₃₇ of the PPO-Cl Polymer Synthesis Example 7 C ₃ Y ₃₇ of the PPO-Cl Polymer Synthesis Example 8 C ₇ Y ₃₇ of the PPO-Cl Polymer and Preparation Example 9 C ₁₁ Y ₃₇ PPO-Cl &lt; / RTI &gt; polymers were measured by gel permeation chromatography.

As shown in FIG. 3B, it was confirmed that the chloromethylation conversion was 37%, and the error rate was around 0.5%. Of the polymer molecular weight was a result of measuring a molecular weight as an important factor affecting the polymer film morphology, physical properties and electric conductivity, and Comparative Example 1 of the C ₀ Y ₃₇ PPO-Cl polymer of Synthesis Example 7 C ₃ Y ₃₇ PPO-Cl Polymer , The C ₇ Y ₃₇ PPO-Cl polymer of Synthesis Example 8 and the M _n and M _W of the C ₁₁ Y ₃₇ PPO-Cl polymer of Synthesis Example 9 tended to slightly increase, It is believed to have occurred because of the different proportions of monomers.

4 is a graph showing changes in ion exchange capacity (IEC) of a thin film before and after drying and a change in ion exchange capacity (IEC) according to temperature (20 ° C., 40 ° C., 60 ° C., 80 ° C., Lt; 0 &gt; C) hydroxide ion conductivity (mS / cm).

division IEC (meq / g) Moisture content (%) Ion conductivity (mS / cm), 100% RH The Exp 20 ℃ 80 ℃ 20 ℃ 40 ℃ 60 ° C 80 ℃ Comparative Example 1
C ₀ Y ₃₇ PPO-QA 2.51 2.13 33.7 62.2 37.6 54.9 72.3 84.9 Example 1
C ₃ Y ₃₇ PPO-QA 2.43 2.02 35.2 63.9 39.1 56.2 77.5 87.5 Example 2
C ₇ Y ₃₇ PPO-QA 2.32 1.95 40.0 69.6 44.8 65.1 84.1 94.0 Example 3
C ₁₁ Y ₃₇ PPO-QA 2.23 1.92 42.2 74.8 46.0 70.11 88.9 101.9

At this time, the ion exchange capacity (IEC) was determined by a back titration method. First, a membrane of 20 mg hydroxy (OH ^- ) was immersed in a 0.01 M HCl standard solution for 48 hours. The acid solution was then titrated with 0.01 M NaOH solution until the solution reached neutral pH. Phenolphthalein was used as an indicator and the ion exchange capacity (IEC) was calculated from the titration record using the following formula.

[Formula 1]

In this formula,

V _{0 NaOH} and V _{x NaOH} are the volume of NaOH consumed in the absence of the respective thin film or thin film, C _NaOH is the molar concentration of NaOH titrated by the standard oxalic acid solution, and W _dry is the weight of the dried film, and the volume measurement IEC (IEC _V ) can be calculated from the following equation:

[Formula 2]

[Formula 3]

Total water uptake (%) and swelling ratios were measured at 20 ° C or 80 ° C as described below. The film was immersed in distilled water for 24 hours, wiped with filter paper and immediately weighed (W _wet , t _wet ). The film was then dried under vacuum at 80 캜 until a constant weight was obtained (W _dry , t _dry ). The water absorption and the dimensional change of the thin film were determined by the following equation.

Water absorption (WU _W ) (wt%) = [(W _wet - W _dry ) / W _dry ]

Dimensional change (Δt) = [(t _wet - t _dry ) / t _dry ] ㅧ 100

Where W _wet and W _dry are respectively the weight of the wet film and the weight of the dried film, and t _wet and t _dry are the thickness of the film and the thickness of the dried film, respectively.

Water absorption (WU _V ) due to volume was also determined by the following equation.

[Formula 4]

Where rho _w and rho _m are the density of the dried film and water, respectively. Three repetitive measurements were made from each film and the IEC, moisture absorption and dimensional changes were averaged over three measurements.

Moisture absorption is one of the most important properties for anion exchange membranes. If moisture absorption is high and the dimensional change is low, it can be said that the damage of the thin film due to the temperature change is minimized. Therefore, the water absorption change (water content (%)) of the anion exchange membrane for a fuel cell according to the present invention was analyzed and shown in Table 1 above.

As a result of comparing the theoretical IEC and hydroxide ion conductivities of the anion exchange membranes of Examples 1 to 3 and Comparative Example 3 based on Table 1, it was found that the anion exchange membrane of Comparative Example 3 had the highest IEC and the anion exchange membranes of Example 3 Of the anion exchange membranes have the lowest IEC values.

In the polymers used in the anion exchange membranes of Examples 1 to 3, the molar fraction of the electrophiles (quaternary ammonium groups) introduced into the polymer main chain was 37 mol%, which is all the same. That is, although the content of the conductive agent is the same, the mass of the entire polymer increases with the increase of the alkyl content, so that the respective IEC values are different from each other.

Generally, the water content increases with the increase of IEC, which is an index of the number of conductors (meq), based on the polymer mass (g), and the conductivity of the hydroxide ion increases as the water content increases. The water content of the anion exchange membranes of Examples 1 to 3 and Comparative Example 3 was measured at 20 占 폚 and 80 占 폚 on the basis of this data (Table 1). The anion exchange membrane of Comparative Example 3 showed a water content of 33.7% at 20 ° C and 62.2% at 80 ° C, and the anion exchange membrane of Example 3 was observed at 42.2% at 20 ° C and 74.8% at 80 ° C. That is, it was confirmed that the water content increases as the alkyl content increases. This is because the introduction of alkyl into the polymer interferes with and weakens the interactions between the backbone of the polymers, thereby providing an additional free-volume and relatively more moisture content.

The hydroxyl ion conductivity of the anion exchange membranes of Examples 1 to 3 and Comparative Example 3 was measured at 20 ° C, 40 ° C, 60 ° C and 80 ° C under 100% RH conditions And Table 1), and the anion exchange membrane of Comparative Example 3 exhibited 37.6 mS / cm and 101.9 mS / cm at 20 ° C and 80 ° C, respectively.

In general, the higher the IEC, the greater the conductivity. However, in the anion exchange membranes of Examples 1 to 3, as the content of the alkyl group was increased, the IEC was decreased while the conductivity and the water content were increased. This can be explained by the relationship between the hydroxide ion conductivity and the water content. First, the hydroxide ion conductivity is basically influenced by the ion diffusion, and the diffusion of the hydroxide ion (OH &lt; ^- &gt; It is considered that the hydroxide ion conductivity in the anion exchange membranes 1 to 3 can be improved.

In addition, since the anion exchange membranes of Examples 1 to 3 are relatively excellent in water content at different temperatures, the dissociation between the conductive agent and the ions is facilitated, the dissociated hydroxide ions are increased, and the number of ions diffused increases, Although the IEC of the anion exchange membranes of Examples 1 to 3 is low, the conductivity of the anion exchange membranes of Comparative Example 3 is improved to a significant degree.

Of the anion exchange membranes of Examples 1 to 3, the anion exchange membrane of Example 3 had a water content of 10 to 12% higher than that of the anion exchange membrane of Comparative Example 3, although the IEC was 0.28 meq / g, 17 mS / cm was further improved.

Figure 5 is a DSC graph showing the DSC characteristics according to Preparation Example 7 to 9 and Comparative Examples 1 to the C _n Y _m using PPO-Cl, prepared, and each of the heating conditions, these films prepared in accordance with, the content of the alkyl group To determine the additional free-volume of the polymer backbone.

In order to exclude the decomposition effect of the electroconductor at high temperature, DSC was prepared by film-forming the C _n Y _m PPO-Cl polymer prepared according to Synthesis Examples 7 to 9 and Comparative Example 1 in which quaternary ammonium conductivity was not introduced, Respectively.

As shown in FIG. 5, the glass transition temperature (T _g ) and phase behavior of each of the C _n Y _m PPO-Cl polymers prepared according to Synthesis Examples 7 to 9 and Comparative Example 1 were examined _. Y ₃₇ The membrane made of PPO-Cl polymer had T _gr observed at around 214 ° C., and each membrane made of C _n Y _m PPO-Cl polymer of Synthesis Examples 7 to 9 in which the content of alkyl groups was increased gradually increased to T _g was found to decrease. Specifically, the film made from the C ₁₁ Y ₃₇ PPO-Cl polymer of Synthesis Example 9 had a T _g at 174 ° C., which is about 40 ° C. lower than the film made from the C ₀ Y ₃₇ PPO-Cl polymer of Comparative Example 1.

It is believed that this is because, in the polymer backbone chain, as the alkyl chain is introduced into the side chain, it plays the same role as the plasticizer, weakening the interaction between the additional polymer backbone and thus generating a large amount of free-volume.

In addition, the density of the anion exchange membranes of Examples 1 to 3 and Comparative Example 3 was calculated by measuring the OH-form (hydroxide form) when completely dried and hydrated. At this time, the calculation is based on the Arrhenius method, and is shown in Table 2 by calculation using heptane (density = 0.679 g / cm 3).

division Density (g / cm3) Dry Wet Comparative Example 3
C ₀ Y ₃₇ PPO-QA 1.17 1.12 Example 1
C ₃ Y ₃₇ PPO-QA 1.15 1.11 Example 2
C ₇ Y ₃₇ PPO-QA 1.10 1.07 Example 3
C ₁₁ Y ₃₇ PPO-QA 1.08 1.03

As shown in Table 2, the density in the dry state and the density in the hydration state of the anion exchange membrane prepared according to Comparative Example 3 were measured. The anion exchange membrane of Comparative Example 3 had a density of 1.17 g / cm 3 when dry and a density of 1.12 g / cm 3 when hydrated. Specifically, the anion exchange membrane of Example 3 had a density of 1.08 g / cm &lt; 3 &gt; in a dry state and a density of 1.03 g / cm &lt; 3 &gt; in a hydrated state, while the anion exchange membranes of Examples 1 to 3 decreased in density as the degree of introduction of alkyl groups increased. / Cm &lt; 3 &gt;. It can be seen that this tendency is the same as the DSC result in Fig.

6 is a graph showing changes in tensile strength (MPa) according to elongation percentages of the anion exchange membranes for fuel cells prepared according to Examples 1 to 3 and Comparative Example 3 (under 50% RH , OH ^- form (hydroxide form, measured at 20 ° C and 80 ° C respectively). The results of FIG. 6 are summarized in Table 3.

division Moisture content (%)
Water uptake Swelling rate (%)
Swelling ratio (%) λ value (#) 20 ℃ 80 ℃ 20 ° C (Δt) 80 ° C (Δt) 20 ℃ 80 ℃ Comparative Example 3
C ₀ Y ₃₇ PPO-QA 33.7 62.2 21.0 28.9 8.8 16.3 Example 1
C ₃ Y ₃₇ PPO-QA 35.2 63.9 21.2 29.5 9.7 17.6 Example 2
C ₇ Y ₃₇ PPO-QA 40.0 69.6 25.2 35.5 11.4 19.8 Example 3
C ₁₁ Y ₃₇ PPO-QA 42.2 74.8 26.6 36.2 12.2 21.3

In order to drive the fuel cell, the anion exchange membrane must have a strong mechanical stability and a low swellin due to high water uptake. Referring to FIG. 6, the anion exchange membrane of Comparative Example 3 exhibits a high tensile strength and tensile strength of 51.7 Mpa and 99.1%, respectively.

On the contrary, the tensile strength and the tensile rate of the anion exchange membrane for fuel cells prepared according to Examples 1 to 3 were continuously decreased as the alkyl content was increased. Finally, the anion exchange membrane of Example 3 had tensile strength and tensile strength of 40.6 Mpa , And 46.0%, respectively.

Basically, the physical properties of the polymer membrane are attributed to crystallinity and amorphousness depending on attraction between the polymer chains. As the alkyl side chain is introduced into the polymer main chain, the free-volume is formed between the main chains, So that the physical properties of the polymer are weakened. However, the anion exchange membranes according to Examples 1 to 3 have relatively poor physical properties as compared with the anion exchange membranes according to Comparative Example 3, and the degree of the anion exchange membranes deviates from a significant degree, or a range (Tensile strength and tensile strength) sufficient to drive the fuel cell.

In addition, the anion exchange membranes of Examples 1 to 3 showed that the increase in the swelling rate (%) did not exceed 10% at the maximum, indicating that the increase in the swelling rate with respect to the lowered mechanical properties and the higher water content was not significant.

Therefore, the anion-exchange membranes of Examples 1 to 3 have a minimum mechanical property and can maintain the physical properties that are harmless to the fuel cell or are not problematic to the fuel cell drive, It has the effect of minimizing the disadvantages and remarkably improving the advantages in that the conductivity is significantly improved. If an additional ionic conductor is introduced to increase the water content in the anion exchange membranes of Examples 1 to 3, it may be possible to improve the hydroxide ion conductivity by improving the IEC. In this case, however, The physical properties may be considerably deteriorated to adversely affect the fuel cell driving, the film shape can not be maintained, or the film can not be used at high temperatures.

The present inventors have recognized such problems and have made efforts to improve them. As a result, they have found a method capable of significantly improving the water content and hydroxide ion conductivity without increasing the IEC. The anion exchange membranes of Examples 1 to 3 can be produced by using conventional or conventional poly Phenylene oxide) polymer will have remarkable or heterogeneous effect.

7 shows the results of measuring the conductivity loss (%) indicating the degree of loss of hydroxide ion conductivity after immersing the anion exchange membranes of Examples 1 to 3 and Comparative Example 3 in a 1M KOH solution under the condition of 80 ° C Fig.

Since the anion exchange membrane is mainly used in an alkali fuel cell and the conduction medium is a strong nucleophilic hydroxide ion (OH ^- ), it accelerates the decomposition of the alkyl group and the quaternary ammonium group introduced into the main chain as well as the polymer main chain . Therefore, anion exchange membranes must have stability under high temperature alkaline conditions in which the fuel cell operates. In order to confirm such alkali stability, the anion exchange membranes of Examples 1 to 3 and Comparative Example 3 were soaked in the presence of 1M KOH at 80 DEG C for 500 hours, and the hydroxide ion conductivity was measured over time.

As shown in FIG. 7, the conductivity of the anion exchange membranes of Examples 1 to 3 and Comparative Example 3 decreased sharply during 100 hours, and gradually decreased until 500 hours. Among them, the anion exchange membrane of Comparative Example 3 was broken after 250 hours. However, the anion exchange membranes of Examples 1 to 3 showed that the hydroxide ion conductivity was reduced to 30 to 40%, but the membrane was maintained intact for up to 500 hours without breakage.

In particular, it was confirmed that the anion exchange membrane of Example 3 only had a conductivity loss of 60% even after 500 hours, and that the anion exchange membrane of Example 3 maintained the 40% hydroxide ion conductivity. The anion exchange membrane of Example 3 had a significant category It can be confirmed that the alkali stability is the most excellent.

The results of the above-mentioned experiment are summarized as follows. In the present invention, in the main chain of poly (1,4-dimethyl-2,6-phenylene oxide), a polymer mainly used in anion exchange membranes, friedel- , Alkyl groups having different carbon number were introduced, alkyl groups were changed, and compositions of the conductors were the same. Thus, various polymers having different alkyl groups were prepared and their various characteristics were analyzed. As a result, compared with the C ₀ Y ₃₇ PPO-QA polymer of Comparative Example 2 in which no alkyl group was introduced at all, the C _n Y _m PPO-Cl-QA polymer of Synthesis Examples 10 to 12 had weak intermolecular macromolecular interactions, -volumes were formed more. Due to the formation of the above free-volume, the C _n Y _m PPO-Cl-QA polymer of Synthesis Examples 10 to 12 had a water content and a hydroxyl ion conductivity even though the IEC was lower than that of the C ₀ Y ₃₇ PPO-QA polymer of Comparative Example 2 And the alkali stability were remarkably improved. Furthermore, it was confirmed that the physical properties were also sufficient for driving the fuel cell because the swelling rate did not increase significantly with respect to the water content.

In other words, the anion exchange membrane according to the present invention increases the IEC to increase the conductivity and the water content, or improves the morphology by introducing an alkyl group into the electroconductor. In contrast, the present invention is different from the present invention in that an alkyl side chain It was possible to improve water content, conductivity and alkali stability without increasing IEC, thereby significantly reducing the occurrence of negative effects or side effects due to the increase in IEC.

Claims (12)

An anion exchange membrane for a fuel cell comprising a poly (phenylene oxide) polymer having a repeating unit represented by the following formula (I).
<Formula I>

In the above formula (I)
Wherein R &lt; ₁ &gt; is any one selected from a linear or branched alkyl group having 6 to 20 carbon atoms,
R ₃ is a quaternary ammonium group of - (R ₁₀ ) N ⁺ (R ₁₁ R ₁₂ R ₁₃ )
Wherein R ₂ , R _4, R ₅ , R ₆ , R ₇ , R ₈ and R ₉ are the same or different from each other and selected from the group consisting of hydrogen, straight or branched alkyl groups having 1 to 6 carbon atoms,
R ₁₀ , R _11, R ₁₂ , and R ₁₃ are the same or different from each other and selected from the group consisting of hydrogen, a linear or branched alkyl group having 1 to 6 carbon atoms,
X, y, and z are each an arbitrary repeating unit, and x, y, and z are mole ratios in the repeating unit, 0.01? X? 0.4, 0.1? Y? 0.5, x + y + z = Or z is not zero. The method according to claim 1,
In Formula (I), R ₁ is any one selected from straight-chain alkyl groups having 10 to 15 carbon atoms,
Wherein R ₂ , R _4, R ₅ , R ₆ , R ₇ , R ₈ and R ₉ are the same as each other and are selected from straight-chain alkyl groups having 1 to 4 carbon atoms. 3. The method of claim 2,
Wherein R ₅ is hydrogen, and R ₁₀ , R _11, R ₁₂ , and R ₁₃ are straight-chain alkyl groups having 1 to 4 carbon atoms. The method of claim 3,
Wherein x is 0.03 to 0.11 and y is 0.3 to 0.4 in the formula (I). The method according to claim 1,
Wherein x is 0.11 and y is 0.37 in the formula (1). The method according to claim 1,
Wherein the anion exchange membrane for fuel cells has a relative humidity of 95 to 100% and a hydroxide ion conductivity of 39 to 110 mS / cm at 20 to 100 占 폚. A separator for a battery comprising an anion exchange membrane for a fuel cell according to claim 1. A fuel cell comprising the separator for a battery according to claim 7. (I) A polymer having a chloromethylated poly (phenylene oxide) polymer having a repeating unit represented by the following formula (II) is dissolved in an organic solvent and a compound having an anion-exchange group is added and reacted to produce a polymer represented by the formula Obtaining a poly (phenylene oxide) polymer having a repeating unit; And
(II) forming a poly (phenylene oxide) polymer thin film having a repeating unit represented by the formula (I) obtained in the step (I).
&Lt; Formula (II)

(Wherein R &_lt; ₁ &_gt; R ₂ , R _4, R ₅ , R ₆ , R ₇ , R ₈ , R ₉ and x, y and z are as defined in formula (I)
In the above formula (II), X is a single bond or (CH ₂ ) _q ( ₁ ? _{Q? 4} ). 10. The method of claim 9,
The chloromethylated poly (phenylene oxide) polymer having the repeating unit represented by the above formula (II)
a) synthesizing an acrylated poly (phenylene oxide) polymer by reacting a poly (phenylene oxide) polymer with aluminum chloride and lauryl chloride;
b) reducing the acrylated poly (phenylene oxide) polymer of step a) to obtain a reduced poly (phenylene oxide) polymer having a repeating unit represented by the following formula (III); And
c) reacting the reduced poly (phenylene oxide) polymer of step b) with zinc chloride and chloromethyl methyl ether. The method for producing an anion exchange membrane for a fuel cell according to claim 1,
&Lt; Formula (III)

(In the above formula (III), R ₁₄ is any one selected from a linear or branched alkyl group having 6 to 20 carbon atoms,
remind R ₁₅ , R _16, R ₁₇ , R ₁₈ , and R ₁₉ are the same or different from each other and selected from the group consisting of hydrogen, a linear or branched alkyl group having 1 to 6 carbon atoms,
O and p are arbitrary repeating units, and o and p are mole fractions in the repeating unit, respectively, 0.0? O? 0.9, 0.1? P? 0.9, o + p = 1. 10. The method of claim 9,
Wherein the compound having an anion-exchange group is quaternary ammonium. 10. The method of claim 9,
Wherein the mixing weight ratio of the chloromethylated poly (phenylene oxide) polymer having the repeating unit represented by the formula (II) to the compound having an anion-exchange group in the step (I) is 1: 0.1 to 1, Gt;

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