KR20180011569A - Sulfonated polytetraphenyl benzophenone copolymer and method for preparing the same - Google Patents

Abstract

The present invention relates to: a sulfonated polytetraphenyl benzophenone copolymer (SPTBP); a manufacturing method thereof; a polymer electrolyte membrane including the sulfonated polytetraphenyl benzophenone copolymer; and a fuel cell including the same. The SPTBP according to the present invention performs carbon-carbon bonding to a center chain to improve the flexibility and other properties of the polymer, and has an effect of obtaining a high molecular weight without an ether group and a benzoyl moiety. In addition, the polymer electrolyte membrane (hereinafter referred to as a membrane) including the SPTBP copolymer of the present invention has an effect of improving properties such as hydrogen ion conductivity, dimensional stability, moisture absorption and the like.

Description

Sulfonated polytetraphenylbenzophenone copolymers and methods for preparing the same are disclosed.

The present invention relates to a sulfonated polytetraphenylbenzophenone copolymer, a method for producing the same, a polymer electrolyte membrane containing the same, and a fuel cell comprising the same, and more particularly, to a fuel cell including a carbon- To a sulfonated polytetraphenylbenzophenone copolymer.

For centuries, industrial sites and living standards have been developed by utilizing many energy sources. These developments are based on the use of natural resources, and subsequent use can lead to depletion of fuel. To date, many researchers have developed alternative energy sources such as wind, hydro, solar, and fuel cells to prevent depletion of fuel. In particular, a polymer electrolyte membrane fuel cell (PEMFC) can effectively utilize mobility due to its high power density, conversion efficiency, and environmental friendliness.

Polymer to the sulfonated perfluoro ^{(Dupont's Nafion ®, 3M Aquivion} TM) are widely used in PEM due to the excellent chemical stability and high hydrogen ion (proton) conductivity. However, such membranes have major drawbacks such as high methanol permeability, complicated manufacturing processes, and degradation of performance at temperatures above 100 < 0 > C. Thus, sulfonated aromatic hydrocarbon membranes have been studied as an alternative to PEM.

Non-patent documents have suggested a way to improve the performance of sulfonated aromatic hydrocarbon membranes by changing the design of the polymer structure, and mentioned two important points in polymer synthesis. First, the block copolymer exhibits a higher hydrogen ion (proton) conductivity than random copolymers with similar ion exchange capacity (IEC) due to the apparent phase separation of the hydrophilic and hydrophobic portions of the block copolymer And the second is that the side chain sulfonation is more reactive than the center chain sulfonation.

As a result, many inventors have studied sulphonated aromatic polymers (polymers) such as poly (ether sulfone), poly (ether ether ketone), poly (arylene ether sulfone), block copolymer, pendant type or comb type copolymer Respectively. These polymers have attracted attention due to their high thermal, oxidative and chemical stability close to Nafion's performance.

However, chemical stability does not come close to Naphion because the ether bond with an acid functional group is attacked by hydrogen peroxide or peroxide radicals produced during PEMFC operation. To improve the chemical stability, polymers having no ether bond in polyphenylene or in all carbon structures have been proposed in the polymer center chain. These polymers were prepared by a Diels-Alder, strong acid catalyst and nickel catalyzed reaction. Non-patent documents have synthesized polymers by the Diels-Alder polymerization, but commercialization of this method has been limited due to the high cost of the monomers. Usually, a palladium catalyst is used in the carbon-carbon bond reaction (Suzuki reaction), but the nickel catalyst is more reactive to the aromatic structure than the palladium catalyst, so that it is efficient.

The non-patent literature has proposed that polymers include benzoyl groups and have advantages such as high ionic conductivity, good chemical and physical properties, and the like. In addition, the Parmax product is one of the commercially useful inventions containing a benzoyl group on the side chain. The benzoyl group of the side chain affects surface properties including surface morphology and other properties.

The inventors of the present invention have studied polymer structures without ether linkages using nickel catalysis. It is an object of the present invention to prepare carbon-carbon bonded polymers in the center chain without ether groups and benzoyl moieties in order to improve the chemical stability, flexibility and molecular weight of the polymers. Due to the presence of electron-attracting groups near the chloride, the ketone groups of tetraphenyl monomer and 1,4-dichloro-2,5-dibenzoylbenzene have high molecular weights.

In the present invention, it is preferable to use 1,2-bis (4-chlorobenzoyl) -3,6-diphenylbenzene and 1,4-dichloro-2,5-dibenzoylbenzene as catalysts from nickel, triphenylphosphine and zinc (Diketone phenylene) comprising a dibenzoyl moiety.

U.S. Patent No. 5,869,599 (Mar. 2, 1999) Korean Patent Publication No. 2011-0066614 (June 17, 2011)

Gross M, Maier G, Fuller T, MacKinnon S, Gittleman C. Kreuer KD.In: Vielstich W, Gasteiger HA, Lamme, Yokokawa H, editors. Handbook of Fuel Cells, New York: John Wiley & Sons Ltd (2010) Ghassemi H, McGrath JE. Polymer 45: 5847-54 (2004) Zhang X, Sheng L, Higashihara T, Ueda M. Polymer Chemistry 4: 1235-42 (2013)

The present inventors have found that when a polymer structure composed of dicetone as a center chain and dibenzoyl as a side chain is synthesized while studying a polymer structure having no ether bond by using a nickel catalyzed reaction, the chemical stability, flexibility and molecular weight of the polymer are improved Respectively. Accordingly, it is an object of the present invention to provide a sulfonated poly (diketonophenylene) copolymer containing a dibenzoyl moiety.

According to one aspect of the present invention, there is provided a sulfonated polytetraphenylbenzophenone (SPTBP) copolymer comprising a unit represented by the following general formula (1) and general formula (2)

[Chemical Formula 1]

(2)

In the above formula, 100 <m <500 and 100 <n <500.

According to another aspect of the present invention, there is provided a polymer electrolyte membrane comprising the sulfonated polytetraphenylbenzophenone (SPTBP) copolymer.

According to still another aspect of the present invention, there is provided a membrane-electrode assembly including the polymer electrolyte membrane.

According to still another aspect of the present invention, there is provided a fuel cell including the membrane-electrode assembly.

According to still another aspect of the present invention, there is provided a process for producing a sulfonated polytetraphenylbenzophenone (SPTBP)

(A) reacting a compound represented by the following formula (4) with a compound represented by the following formula (5) to prepare a compound represented by the following formula (6);

(B) sulfonating a compound represented by the following formula (6) to prepare a compound represented by the following formula (3): &lt; EMI ID =

(3)

[Chemical Formula 4]

[Chemical Formula 5]

[Chemical Formula 6]

In the above formula, 100 <m <500 and 100 <n <500.

It has been found that the sulfonated polytetraphenylbenzophenone (SPTBP) copolymer according to the present invention is carbon-carbon bonded to the center chain without an ether group and a benzoyl moiety to improve the properties such as flexibility of the polymer and have a high molecular weight .

Further, the polymer electrolyte membrane (hereinafter referred to as a membrane) containing the sulfonated polytetraphenylbenzophenone (SPTBP) copolymer of the present invention has an effect of improving the properties such as hydrogen ion conductivity, dimensional stability, and moisture absorption.

Figure 1 is a ¹ H NMR spectrum of tetraphenyl and dibenzoyl monomers.
Figure 2 is a ¹ H NMR spectrum of PTBP and SPTBP polymers.
Figure 3 shows the thermal-oxidation stability of PTBP and SPTBPs.
4 shows the hydrogen ion conductivity of the membrane at 80 DEG C under 30 to 90% RH.
Figure 5 shows the hydrogen ion conductivity of the membrane at 30 ° C to 80 ° C under 90% RH.
FIG. 6 is an atomic force microscope photograph of SPTBP 3 and SPTBP 9. FIG.

Hereinafter, a sulfonated polytetraphenylbenzophenone copolymer, a polymer electrolyte membrane including the sulfonated polytetraphenylbenzophenone copolymer, and a fuel cell including the sulfonated polytetraphenylbenzophenone copolymer according to an embodiment of the present invention will be described in detail.

The present invention provides a sulfonated polytetraphenylbenzophenone (SPTBP) copolymer comprising a unit represented by the following general formulas (1) and (2):

[Chemical Formula 1]

(2)

In the above formula, 100 <m <500 and 100 <n <500.

Due to the sulfone groups contained in the copolymer, the reactivity is increased, and high hydrogen ion conductivity can be obtained.

In the copolymer, the ratio of m: n is preferably 1: 9 to 9: 1, and more preferably the ratio m: n is 2: 8. The ratio of m: n is suitable for obtaining a high molecular weight.

The weight average molecular weight of the copolymer is not particularly limited, but is preferably 50,000 to 200,000, more preferably 80,000 to 180,000, and most preferably 100,000 to 150,000. The weight average molecular weight range is suitable for achieving the object of the present invention.

The sulfonated polytetraphenylbenzophenone (SPTBP) polymer according to the present invention has a structure in which carbon-carbon bonds to the center chain and a sulfone group is introduced to the side chain, and the polymer has flexibility and can have a high molecular weight. Also, the sulfone group is introduced into the side chain, so that the hydrophilic-hydrophobic part of the polymer is separated and the hydrogen ion conductivity can be improved.

Further, the polymer electrolyte membrane (hereinafter referred to as a membrane) containing the sulfonated polytetraphenylbenzophenone (SPTBP) copolymer of the present invention has an effect of improving the properties such as hydrogen ion conductivity, dimensional stability, and moisture absorption.

According to another embodiment of the present invention, there is provided a polymer electrolyte membrane comprising the copolymer. The polymer electrolyte membrane contains sulfone groups and has high hydrogen ion conductivity. And it has excellent water absorption property.

According to another embodiment of the present invention, there is provided a membrane-electrode assembly including the polymer electrolyte membrane. According to another embodiment of the present invention, there is provided a fuel cell including the membrane-electrode assembly.

The fuel cell may include a cathode, an anode, and the polymer electrolyte membrane sandwiched therebetween.

According to another embodiment of the present invention, there is provided a process for producing a sulfonated polytetraphenylbenzophenone (SPTBP) copolymer represented by the following general formula (3)

(A) reacting a compound represented by the following formula (4) with a compound represented by the following formula (5) to prepare a compound represented by the following formula (6);

(B) sulfonating a compound represented by the following formula (6) to prepare a compound represented by the following formula (3): &lt; EMI ID =

(3)

[Chemical Formula 4]

[Chemical Formula 5]

[Chemical Formula 6]

In the above formula, 100 <m <500 and 100 <n <500.

Wherein the step (A) is performed in the presence of nickel (Ni), phosphine (PPH ₃ ) and zinc (Zn). The nickel, phosphine (triphenylphosphine) and zinc may be stored under nitrogen. As the solvent, DMAc or DMSO may be used, but not always limited thereto.

The molar ratio of nickel (Ni), phosphine (PPH ₃ ) and zinc (Zn) is 60: 8: 1. The above-mentioned molar ratio is suitable for obtaining a high molecular weight.

Hereinafter, the present invention will be described in more detail through examples and test examples. However, the following examples and test examples are provided for illustrating the present invention, and the scope of the present invention is not limited thereto.

Example 1. Sulfonation Polytetraphenyl  Benzophenone ( SPTBP ) Synthesis of

(One) material

Phosphoric acid, bromine, sodium acetate, benzene, 2,5-dichloro-p-xylene, potassium permanganate, pyridine, t-butyldimethylsilyl chloride, Oleyl chloride, nickel bromide, triphenylphosphine and chlorosulfonic acid were purchased from Alfa Aesar and Sigma-Aldrich. Nickel bromide, zinc powder, and triphenylphosphine were stored under nitrogen. The DMAc and DMSO were dried with calcium hydride and distilled, and the dried state was maintained with 3 Å molecular sieves before use. General solvents such as toluene, acetone, carbon disulfide, chloroform, methanol, ethanol, ethylbenzene, acetic anhydride and glacial acetic acid were used without further purification.

(2) 1,2- Bis (4- Chlorobenzoyl ) -3,6- Diphenylbenzene [1,2-bis (4- chlorobenzoyl ) -3,6-diphenylbenzene]

1,2-bis (4-chlorobenzoyl) -3,6-diphenylbenzene was synthesized according to the following procedure. Aluminum chloride (0.25 mol, 33.39 g), chlorobenzene (0.2 mol, 20.28 ml) and carbon disulfide (200 ml) were placed in a 500 ml three-necked round flask and stirred for 10 minutes. Fumaryl chloride (0.1 mol, 10.26 mL) was diluted with carbon disulfide (50 mL) and slowly added dropwise over 30 min. The mixture was refluxed for 24 hours.

After the reaction, the solution was poured into an HCl solution (in ice). The obtained product was washed with water, dichloromethane was added, and the organic layer was separated. The organic layer was evaporated, washed with ethanol and recrystallized with toluene. The resulting yellow solid (0.03 mol, 10 g) was dissolved in ethylbenzene (250 ml) in a 500 ml two-necked round-bottomed flask and then trans-trans-1,4-diphenyl-1,3-butadiene (0.03 mol, g).

After this time, the mixture was refluxed for 24 hours to evaporate the solvent. The product was recrystallized from ethanol and dried in an oven at 80 DEG C for 12 hours. A white solid (15 g) mixture in acetic anhydride (600 mL) was added to 86% syrupy phosphoric acid (0.4 g) and refluxed in a 1 L 2-neck round flask. The mixture was stirred for 1 hour before being cooled and recrystallized from ethanol. In a 250 ml three-necked round flask, 1,3-bis (4-chlorophenyl) -4,7-dihydro-4,7-diphenylisobenocoufuran (0.01 mol, 5 g) was dissolved in glacial acetic acid And a solution of bromine (0.02 mol, 1 mL) in glacial acetic acid (5 mL) was added dropwise over 10 minutes. The mixture was refluxed for 1 hour. Subsequently, sodium acetate (0.08 mol, 8 g) was added, and the mixture was continuously stirred at 80 캜 for 30 minutes. Water was added to the mixture and allowed to cool slowly for several hours. The white solid 7B was filtered and recrystallized from ethanol.

(3) 2,5- Dichloro -1,4- Dibenzoylbenzene [2,5- dichloro -1,4- dibenzoylbenzene ] Synthesis of

2,5-Dichloro-1,4-dibenzoylbenzene was prepared according to the following procedure. (10 g, 42 mmol), potassium permanganate (54.5 g, 354 mmol), pyridine (162 mL, 2048 mmol) and distilled water (50 mL) were placed in a 500 mL round- At room temperature). After 1 hour, the mixture was refluxed for 24 hours. Manganese was removed by celite filtration and washed with hot water. The filtrate was evaporated to give a white solid which was then dissolved in water. HCI was added to the solution until pH 2 was reached.

Dichloroterephthalic acid (10 g, 0.04 mol) was stirred with thionyl chloride (30 mL, 0.4 mol) for 24 hours under reflux conditions. The solution was evaporated and immediately 5 ml of carbon disulfide was added for the next step. Benzene (9.4 mL, 0.1 mol), aluminum chloride (28.36 g, 0.21 mol) was dissolved in 250 mL of carbon disulfide and the chloride monomer was added dropwise for 10 minutes. The mixture was stirred for 24 h at 40 &lt; 0 &gt; C and the residue was poured into ice water with hydrochloric acid. The product was washed twice with filtration and water, recrystallized from ethyl acetate and hexane and dried in an oven at 60 &lt; 0 &gt; C.

(4) Polytetraphenyl  Benzophenone [ 폴리 테레 피렌 benzophenone , PTBP ] Synthesis of

A 1-necked, 3-necked flask was prepared to accommodate the catalyst and monomers in the glove box. Nickel bromide (0.0978 g, 0.0004 mol), zinc powder (1.757 g, 0.0268 mol) and triphenylphosphine (0.9409 g, 0.0035 mol) were placed in a 100 ml three-necked flask, and another round flask was charged with 7b (1 g, 0.0019 mol) and PBP (1.4 g, 0.0039 mol).

 Nitrogen gas was allowed to flow out of the glove box to prevent moisture. To activate the catalyst, 3 ml of DMAC was injected using a syringe (needle) and the temperature was raised to 90 ° C. DMAC (12 mL) was injected to dissolve the monomer, and the monomer was injected into the flask containing the catalyst. The reaction was carried out at 100 &lt; 0 &gt; C for 24 hours. The polymer was poured into water containing 30% hydrochloric acid. The yellow solid was filtered off, washed with methanol and water and then dried in an oven at 60 [deg.] C.

(5) Sulfonation Polytetraphenyl  Benzophenone [ ulfonated 폴리 테레 피렌  benzophenone, SPTBP]

The synthesized polymer was dissolved in chloroform at room temperature, and chlorosulfonic acid was added. 0.504 mL was slowly added dropwise and the mixture was stirred for 4 hours.

After the reaction, the mixture was slowly poured into distilled water, washed several times to remove residual acid, and then dried in an oven at 60 ° C for 24 hours.

Example 2. Preparation of polymer electrolyte membrane

Films (25 μm) were prepared with a 20 wt% filtered polymer in DMSO to obtain a clear film over a flat glass plate (5 cm × 5 cm) at ambient temperatures of 60, 80, 100 and 120 ° C.

Test Example 1. Characterization

[Test Methods]

(1) 1 ^H NMR spectrum was recorded on a Bruker DRX spectrometer (400 MHz) using tetramethylsilane (TMS) as an internal standard.

(2) Thermogravimetric analysis was performed using a thermogravimetric analyzer (Scinco TGA-1000N) at 30 to 800 ° C under a temperature raising rate of 10 ° C / min. The analysis was carried out by measuring the drying and humidity of the membrane, vacuum drying at 100 ° C for 24 hours, weighing and immersion in deionized water at 30 ° C and 80 ° C for 24 hours.

(3) Moisture absorption of the membrane was measured by three samples (SPTBP 3, SPTBP 6, SPTBP 9) and calculated as the adsorption ratio of water to the dried sample as shown in the following equation (1).

[Equation 1]

Water absorption (%) = [(Wwet - Wdry) / Wdry] x 100 where Wwet and Wdry are the weights of the wet and dry film, respectively.

(4) The ion exchange capacity (IEC) of the acid function of the membrane was measured by the following suitable method. The acid form (H ⁺ ) of the membrane was immersed in 20 ml of a 2.0 M NaCl solution at 80 DEG C for 24 hours and then converted to the sodium salt form.

(5) The hydrogen ion conductivity was measured using a through-plane membrane test system (Scribner Associates Inc., MTS 740) equipped with a Newtons 4th Ltd (N4L) impedance analysis interface (PSM 1735) The membrane was hydrated with distilled water for 24 hours at room temperature and placed in a sealed cell. Hydrogen ion conductivity was obtained by measuring the AC potential difference between the two electrodes in the middle of the membrane. While applying a constant alternating current to both electrodes, it was 80 DEG C under 30 DEG C to 80 DEG C and 30 to 90% RH under 90% RH. The frequency dependence of the cell impedance was measured at 10 mV over an AC voltage frequency of 1 to 10 ⁵ Hz.

6 is an atomic force microscope (AFM) pictures are force constant of about 20 Nm ^- using a micro fabricated cantilever ^1, was measured by a measuring device (PSIA XE100 and the SII-NT SPA400). The synthesized polymer film surface was applied in a non-contact mode with P / N-910M NCHR tips.

[result]

(1) Characterization of monomers and polymers

Two monomers of 1,4-dichloro-2,5-, dibenzophenone and 1,2-bis (4-chlorobenzoyl) -3,6-diphenylbenzene were synthesized and shown in Scheme 1 below.

[Reaction Scheme 1]

The 1,2-bis (4-chlorobenzoyl) -3,6-diphenylbenzene can be synthesized by the reaction of a trans-1,4-diphenyl-1,3-butadiene with a Diels-Alder reaction and an aluminum chloride with a Friedel- Lt; RTI ID = 0.0 &gt; 4-step &lt; / RTI &gt; The substituted cyclohexene was converted to a complete aromatic structure via the dihydroisobenzofuran intermediate. The above monomer, 1,4-dichloro-2-benzophenone, has a symmetrical structure of benzoyl group and acts as a highly reactive site in nickel-zinc catalyzed polymerization due to electron-attracting group in the vicinity of chloride. The chemical structure of the synthesized monomers was confirmed by ¹ H NMR spectroscopy. All of the monomers were identified as consisting of aromatic rings and ketone groups.

1, the peaks of 1,2-bis (4-chlorobenzoyl) -3,6-diphenylbenzene were 7.14 (H _a ), 7.45 to 7.50 (H _b ), 7.60 (H _c ) 7.26 (H _d ~ H _f ) ppm. H _a was moved by the chloride, H _b was moved by the ketone group, and H _c was shifted by the steric hindrance of benzene. In PBP, the aromatic proton peak was identified at 7.51-7.6 ppm, but the proton peak near chloride was characterized by 7.48 or 7.92 ppm due to the electron-accepting or conjugative effect of chloride. Also, the proton peak near the ketone appeared at 7.84 to 7.87 ppm.

A series of SPTBPs were prepared using Suzuki couples using a nickel-phosphine-zinc catalyst with 1,2-bis (4-chlorobenzoyl) -3,6- Ring reaction. This reaction is shown in Scheme 1 above. The ratio of zinc, nickel bromide and triphenylphosphine catalyst is an important factor for increasing the molecular weight, and a suitable molar ratio of the catalyst in the present invention is 60: 8: 1. The polymer has a molecular weight (Mw) of 110,500 to 124,200. (SPTBP 3, SPTBP 6, SPTBP 9) with different monomer (monomer) ratios (n: m = 1: 9, 2: 8, 3: 7). In order to increase the molecular weight of the polymer, 1,2-bis (4-chlorobenzoyl) -3,6-diphenylbenzene: 2,5-dichloro-1,4-dibenzoylbenzene]. As a result, a high molecular weight polymer was obtained when the monomer ratio was 2: 8. Since the chlorosulfonic acid tends to be insoluble in concentrated sulfuric acid, the sulfonation reaction was controlled by the amount of chlorosulfonic acid. The obtained polymer had a weight average molecular weight (Mw) of 116,700 to 132,500.

The chemical structure of the PTBP polymer was investigated by 1H NMR spectroscopy using CDCl ₃ and DMSO-d ₆ as solvents and reference materials. Figure 2 shows ¹ H NMR spectra of PTBP and SPTBP. Since the structure of the polymer is linked by aromatic rings and ketone groups, the signal of the phenyl protons in PTBP appeared at 7.0 to 7.6 ppm. Of these, the proton near the ketone group was about 7.6 ppm. In SPTBP, the integration value of the phenyl protons decreased from 7.2 to 7.3 ppm, and the delocalized protons appeared in the down field (7.4 to 7.5 ppm) due to the electron donating effect of sulfonic acid.

(2) Heat-oxidation stability of membrane

The thermal-oxidation stability of the membrane was examined by TGA (thermogravimetric analyzer). In order to evaluate the thermal-oxidation stability of the polymer, the decomposition curves of the membranes were measured under air atmosphere and are shown in FIG. The weight loss of the polymer in PTBP was observed at 480 ° C. A series of sulfonated polymers exhibited a two step weight loss over 230 ° C to 400 ° C and over 460 ° C. The first weight loss is due to the loss of the sulfone group and the second weight loss is due to the degradation of the polymer chain.

(3) Moisture absorption, IEC, and dimensional stability of membranes

Typically, moisture absorption and dimensional stability are key factors in determining the durability of membranes for operating PEMFC systems. Moisture facilitates proton transfer between membrane and internal devices. However, excessive water absorption inevitably leads to inadequate membrane expansion and subsequent deterioration of mechanical stability.

As shown in Table 1, the water absorption of SPTBP increased gradually with increasing IEC value. The water absorption value of SPTBP was observed at 10.19 ~ 61.22 compared to Nafion 211 ^® 32.13. The ion exchange capacity (IEC) was determined by the sulfonation content and was an indicator of the proton conductivity. As shown in Table 1, the value of the IEC is SPTBP was 1.00 ~ 2.28 meq./g range Nafion 211 ^® IEC value was 0.91 meq./g.

polymer Proper IEC (meq / g) Water absorption ^a (%) t ^b (%) ℓ ^b (%) Hydrogen ion conductivity ^c (mS / cm) SPTPB 3 1.00 10.19 0 0 62.1 SPTPB 6 1.56 38.42 37.12 12.5 89.4 SPTPB 9 2.28 61.22 48.17 15 110.2 Nafion 211 0.91 32.13 14.10 13.84 103.7

a: Moisture absorption at 80 DEG C for 24 hours

b: Dimensional change at 80 캜 in the presence of water

c: Hydrogen ion conductivity at 80 캜 under 90% RH

The dimensional stability of the membrane (electrolyte membrane) is an important factor in relation to changes with temperature and humidity. The dimensional stability of the membrane (electrolyte membrane) is determined by the RH 100% and the through-plane (DELTA t) and the in-plane (DELTA l) of the dry state.

 As a result of the SPTBP membrane (electrolyte membrane), Δt values were 0%, 37.12%, and 48.17%, and Δℓ values were 0%, 12.5%, and 15%, respectively. The value of Δℓ is much lower than the value of Δt, which is also due to the strong carbon-carbon polymer center chain and also because the hydrophilic sulfonic acid is located in the side chain of the polymer.

(4) Proton conductivity and morphology of membrane (electrolyte membrane)

Membrane proton (hydrogen ion) Set the AC impedance spectrometer equipped th surface constant alternating current conductivity to 80 ℃ under 30 ~ 80 ℃ and 30 ~ 90% RH under 90% RH while applying a positive electrode the positive electrode and the negative electrode of the (electrolyte membrane) Respectively.

4, the Nafion 211 ^® conductivity relative humidity (RH) 90%, was measured at 80 ℃ to 103.7 mS / cm, SPTBP membrane (electrolyte membrane) was 62.1, 89.4, 110.2 mS / cm at the same conditions Respectively. Other conditions were tested by varying the temperature from 30 to 80 ° C with a constant relative humidity (RH) of 90%. The results of conductivity at 30 to 80 ° C under the same relative humidity are shown in FIG. 5 by comparing Nafion 211 ^® . As the temperature increased, the conductivity of the membrane (electrolyte membrane) increased and the membrane with a higher IEC value (electrolyte membrane) showed higher hydrogen ion conductivity. However, it was clearly confirmed that the SPTBP membrane (electrolyte membrane) had a low conductivity at 50% RH compared to Nafion 211 ^® .

The morphology of the membrane (electrolyte membrane) was observed by an atomic force microscope (AFM), and the result was shown in the phase photograph of FIG. The bright regions correspond to the domains formed by the hydrophobic aromatic moieties and the dark lead-dye regions represent the local hydrophilic sulfone groups including the water absorbed in the air.

As a result of the examination of the photographs, it was confirmed that the surface pattern reflecting the hydrophilic-hydrophobic microphase separation was strongly dependent on the content of the sulfone group.

As shown in FIG. 6, the dark areas of the SPTBP 3 film (electrolyte membrane) photographs were wider than those exhibited by the SPTBP 9 film due to the high IEC. Fine (micro) was found to have a phase separation and uneven film is structured, high proton conductivity, in particular, it was found to have a higher value than the high IEC value Nafion 211 ^®.

Or to compare Nafion ^® 211 membrane (electrolyte membrane), and the films are 1.00 ~ 2.28 meq./g of IEC, water absorption of 10.19 - 61.22%, 61.2 ~ proton conductivity of 110.2 mS / cm, and a high thermal stability . In particular, the hydrogen ion conductivity of the membrane (electrolyte membrane) SPTBP 9 was higher than that of Nafion 211 ^® . Further, the membrane (electrolytic membrane) having a diketone as a center chain and a dibenzoyl moiety as a side chain without an ether linkage showed a high dimensional stability with a high IEC value. The surface morphology of the polymer matrix has been shown to have a significant effect on the membrane (electrolyte membrane) properties, and the properties of the SPTBP of the present invention will be very useful in fuel cell membrane (electrolyte membrane) applications.

Claims (10)

Sulfonated polytetraphenylbenzophenone (SPTBP) copolymer comprising a unit represented by the following formulas (1) and (2):
[Chemical Formula 1]

(2)

In the above formula, 100 <m <500 and 100 <n <500. The sulfonated polytetraphenylbenzophenone (SPTBP) copolymer according to claim 1, wherein the ratio of m: n is 1: 9 to 9: 1. The method according to claim 1, wherein the ratio of m: n is 2: 8. Polytetraphenylbenzophenone (SPTBP) copolymer. The sulfonated polytetraphenylbenzophenone (SPTBP) copolymer according to claim 1, wherein the copolymer has a weight average molecular weight (Mw) of 50,000 to 200,000. A polymer electrolyte membrane comprising a sulfonated polytetraphenylbenzophenone (SPTBP) copolymer according to any one of claims 1 to 4. A membrane-electrode assembly comprising the polymer electrolyte membrane of claim 5. A fuel cell comprising the membrane-electrode assembly of claim 6. A process for producing a sulfonated polytetraphenylbenzophenone (SPTBP) copolymer represented by the following formula (3)
(A) reacting a compound represented by the following formula (4) with a compound represented by the following formula (5) to prepare a compound represented by the following formula (6); And
(B) sulfonating a compound represented by the following formula (6) to prepare a compound represented by the following formula
&Lt; / RTI &gt;
(3)

[Chemical Formula 4]

[Chemical Formula 5]

[Chemical Formula 6]

In the above formula, 100 <m <500 and 100 <n <500. The method according to claim 8, wherein said step (A) is performed in the presence of nickel (Ni), phosphine (PPH ₃ ) and zinc (Zn). The method according to claim 9, wherein the molar ratio of nickel (Ni), phosphine (PPH ₃ ) and zinc (Zn) is 60: 8:

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