KR20140064308A - Polymer electrolyte membranes prepared from 4,4-bis(4-chlorophenylsulfone)-1,1-biphenyl compound for fuel cells and their manufacturing methods - Google Patents

Abstract

The present invention relates to a method for preparing a polymer electrolyte membrane made of 4,4-bis(4-chlorophenylsulfone)-1,1-biphenyl compound for fuel cells. More specifically, as a method for preparing an electrolyte membrane by producing and using a novel membrane, the objective of the present invention is to provide a polymer electrolyte membrane for fuel cells effectively having ion conductivity at low temperatures and to provide materials capable of being sulfonated for an electrolyte membrane for fuel cells. In the polymer electrolyte membrane of the present invention, as the synthesized sulfonated polymers are added hereto with hydrophobic polymers and copolymers, the polymer electrolyte membrane has excellent ion conductivity and high ion conductivity at low temperatures and in high humidity.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polymer electrolyte membrane for fuel cells comprising 4,4-bis (4-chlorophenylsulfone) -1,1-biphenyl compound, , 1-biphenyl Compound for Fuel Cells and Their Manufacturing Methods}

The present invention relates to a process for producing a polymer electrolyte membrane for a fuel cell made of 4,4-bis (4-chlorophenylsulfone) -1,1-biphenyl compound. And more particularly, to provide a polymer electrolyte membrane for a fuel cell having effective ion conductivity even at a low temperature, and to provide a material for a polymer electrolyte membrane for a fuel cell that can be sulfonated.

A fuel cell is a device that directly converts chemical energy into electrical energy by electrochemical reaction of hydrogen, methanol, ethanol, natural gas, etc. with oxygen and air as a fuel.

Fuel cells have different types according to electrolytes, and typically include polymer electrolyte membrane fuel cells, direct oxidation fuel cells, and direct methanol fuel cells .

Generally, the fuel cell power generation system is a clean energy resource that can be substituted for fossil energy and can be used in various fields such as pollution-free automobile, mobile communication portable power source, household power generation system, and military equipment.

The polymer fuel cell membranes that are currently commercialized are Nafion ^™ , a sulfonated perfluorinated polymer manufactured by DuPont, which exhibits high mechanical strength and ionic conductivity at high humidification. However, applications are limited because of their high cost and low chemical stability.

In order to overcome such disadvantages, the present invention is to develop a polymer fuel cell membrane capable of achieving a high ionic conductivity at a low temperature by designing an inexpensive polymer fuel cell membrane. The prior art related to the present invention (Macromolecules 2011, 44, 38843892) is a multi-block copolymer polymer in which a hydrophilic block and a hydrophobic block are alternately arranged as a hydrocarbon-based polymer electrolyte membrane And a manufacturing method thereof is proposed as an electrolyte membrane. In addition, a polymer was prepared by a method similar to the above, sulfonation was carried out using a chlorosulfuric acid to form a hydrophilic block, and then a hydrophobic block was used to make a block copolymer. However, these prior arts have different technical constructions from the present invention.

An object of the present invention is to provide a polymer electrolyte membrane for a fuel cell having an effective ion conductivity at a low temperature. Another object of the present invention is to provide a material for a polymer electrolyte membrane for a fuel cell capable of easily sulfonating.

To achieve the object of the present invention, the polymer of formula (I) having electrical conductivity provides a polymer electrolyte membrane for a fuel cell, wherein the salt ion having a cationic charge is potassium ion, sodium ion or alkylamine.

...(화학식 1)

(Formula 1)

Y represents a single bond in which carbon and carbon are directly connected to each other, -O-, -S-, or -C (= O) - or -S (= O) _2- , ≪ / = 4, and Z, Z 'and Z''represent one ion-exchange group selected from the group consisting of a sulfonic acid group and a phosphoric acid group.

In the above formula (1), n and m represent repeating units of the polymer, and n and m are 3? N and m? 400, respectively.

According to the present invention, a polymer electrolyte membrane using a copolymer having an excessive sulfonated block has a high ionic conductivity and chemical stability at a low temperature, a suitable humidity, and shows a level equal to or higher than that of a commercially available membrane.

1 shows ¹ H NMR of Example 1 and Example 3. FIG.
Figure 2 shows the FT-IR of unsulfonated / sulfonated polyarylene biphenylsulfone sulfonated block copolymers.
Figure 3 shows the glass transition temperatures of the Nafion 115 / unsulfonated / sulfonated polyarylene biphenylsulfones block copolymers TGA and non-sulfonated / sulfonated polyarylene biphenyl block copolymers.
Figure 4 shows ionic conductivity values of Nafion 115 / sulfonated polyarylene biphenylsulfone sulfonated block copolymers.

The present invention relates to a process for producing a hydrophilic copolymer, comprising the steps of: preparing a hydrophilic copolymer; preparing a hydrophobic copolymer; preparing a sulfonated polyarylene biphenyl sulfone copolymer; and mixing the sulfonated polyarylene biphenyl sulfone sulfone copolymer (4-chlorophenylsulfone) -1,1-biphenyl compound, which comprises the step of preparing a polymer electrolyte membrane by using a 4,4-bis (4-chlorophenylsulfone) -1,1-biphenyl compound.

The sulfonated biphenyl sulfone copolymer having a conductive functional group is represented by the following general formula (2).

...(화학식 2)

(Formula 2)

In the general formula Y 2 is a single bond the carbon-carbon the given directly to, -O-, -S-, -N- -C ( = O) -, -S (= O) 2 - represents the, x is 0, X < = 4, and Z, Z 'and Z "represent one ion-exchange group selected from the group consisting of a sulfonic acid group and a phosphoric acid group.

In the above formula (1), Ar ₁ may be any aromatic compound selected from the following formulas (10-1) to (10-7);

...화학식 10-1

10-1

...화학식 10-2

10-2

...화학식 10-3

10-3

...화학식 10-4

10-4

...화학식 10-5

10-5

...화학식 10-6

10-6

...화학식 10-7

10-7

In the formula (2), n represents a repeating unit of a polymer, and n is an integer of 3? N? 400.

The sulfonated biphenyl sulfone block copolymer having a conductive functional group is represented by the following Formula 1 obtained by reacting the following Formula 2 and Formula 3.

...(화학식 1)

(Formula 1)

...(화학식 2)

(Formula 2)

...(화학식 3)

(Formula 3)

Y is a single bond in which carbon and carbon are directly connected to each other, -O-, -S-, or -C (= O) -, -S (= O) ₂ -;

x is 0? X? 4;

Z, Z ', Z "represents one ion-exchange group selected from the group consisting of a sulfonic acid group and a phosphoric acid group;

Ar ₁ , Ar ₂ , Ar ₃ are The aromatic compound may be any one independently selected from the following formulas (10-1) to (10-7);

...화학식 10-1

10-1

...화학식 10-2

10-2

...화학식 10-3

10-3

...화학식 10-4

10-4

...화학식 10-5

10-5

...화학식 10-6

10-6

...화학식 10-7

10-7

n and m are integers of 3? n and m? 400.

Example 1: Preparation of polyarylene biphenyl sulfone copolymer for hydrophilic polymer

To prepare a polyarylene biphenyl sulfone copolymer represented by the above-mentioned reaction formula (1).

[Reaction Scheme 1]

Materials: 4,4-bis 4 chlorophenylsulfonyl-1,1-biphenyl (BCPSBP) and 4,4-nuclear fluoroisopropylidene diphenol (6F-BPA) were purchased from Sigma-Aldrich.

≪ Synthesis of polyarylene biphenyl sulfone copolymer >

6.8 g of 4,4-bis 4 chlorophenylsulfonyl-1,1-biphenyl (13.5 mmol), 5.0 g of 4,4-hexafluoroisopropyl laden diphenol (14.9 mmol), 3.73 g of potassium carbonate (27 mmol), 25 mL of DMAc and 20 mL of toluene were placed in a magnetic stirrer, Dean-Stark trap, two-neck round bottom flask.

The reaction mixture was reacted at 135 占 폚 for 6 hours, and the toluene was removed at 160 占 폚 for 2 hours. The temperature was maintained at 190 占 폚 for supplying the energy required for polymerizing for 24 hours or longer. The resulting mixture was diluted with tertiary distilled water 1, acetone 1, 6 by weight. The resulting precursor was analyzed by infrared spectroscopy (FT-IR) and nuclear magnetic resonance spectroscopy (NMR).

^{FT-IR: 1015 cm -1 (} s, -O-), 1508, 1594 cm -1 (s, aromatic; C = C), 1064 (s, SO 2) 930cm -1 (-CF 3). ^{1 H NMR (600 MHz, DMSO-} d 6) d 8.1 (8H) 7.8 (4H), 7.4 (4H), 7.2 (8H).

≪ Example 2 > Hydrophobic copolymer preparation

A hydrophobic copolymer represented by the following Reaction Scheme 2 was prepared.

[Reaction Scheme 2]

Materials: 4,4'-hexafluoroisopropyl laden diphenol (6F-BPA) and 4-chlorobenzophenone were purchased from Sigma-Aldrich.

<Synthesis of hydrophobic copolymer>

(16.9 mmol) of 4,4'-hexafluoroisopropylradene diphenol (14.9 mmol), 4.11 g of 4-chlorobenzophenone, 4.12 g of potassium carbonate (26.2 mmol), 25 mL of DMAc and 20 mL of toluene, Stirrer, Dean-Stark trap, two-necked round bottom flask. The reaction mixture was reacted at 135 占 폚 for 6 hours, the toluene was removed at 160 占 폚 for 2 hours, the viscosity was maintained at a temperature of at least 24 hours to supply energy required for polymerizing at 190 占 폚, , And methanol (6).

Example 3: Preparation of hydrophilic sulfonated polyarylene biphenyl sulfone copolymer

To prepare a hydrophilic sulfonated polyarylene biphenylsulfone copolymer represented by the above-mentioned reaction formula (3).

[Reaction Scheme 3]

Materials: polyarylene biphenylsulfone copolymer, methylene chloride, chlorosulfuric acid. Of these, methylene chloride and chlorosulfuric acid were purchased from Daejung Chemical.

<Sulfonation>

0.5 g of the polyarylene biphenyl sulfone polymer was dissolved in 20 mL of methylene chloride, and then 0.2 M of chlorosulfuric acid was slowly dropped and reacted at room temperature for 24 hours. Thereafter, the precipitate was poured into third distilled water and dried at 100 ° C for 24 hours.

&Lt; Example 4 > Preparation of Sulfonated Polyarylene Biphenylsulfone Sulfur Block Copolymer

A sulfonated polyarylene biphenylsulfone sulfonated block copolymer represented by the above-mentioned Reaction Scheme 4 was prepared.

[Reaction Scheme 4]

<Synthesis>

The synthesized hydrophilic sulfonated polyarylene biphenylsulfone copolymer and the hydrophobic copolymer powder were dried at 100 ° C for 24 hours before the synthesis. The dried powders were sulfonated polyarylene biphenylsulfone sulfonate-10 (hydrophilic sulfonated polyarylene biphenyl sulfone: hydrophobic copolymer = 0.1: 0.9, 0.3: 0.7, 0.5: 0.5) , Sulfonated polyarylene biphenylsulfone sulfonate-30, and sulfonated polyarylene biphenylsulfone sulfonate-50 were synthesized. The synthetic method involves the addition of excess potassium carbonate, 25 mL of DMAc and 20 mL of toluene were charged into a magnetic stirrer, Dean-Stark trap, two-neck round bottom flask. The reaction was carried out at 135 DEG C for 6 hours, the toluene was removed at 160 DEG C for 2 hours, and the viscosity of the mixture was maintained at the temperature for more than 24 hours to supply the energy required for polymerizing at 190 DEG C, and the mixture was precipitated in tertiary distilled water . The synthesized block copolymer was washed with tertiary distilled water and methanol, and was formed into 8 wt% of DMAc.

In the above formula, x and y are 0? X and y? 1.

&Lt; Example 4-1 > Manufacture of sulfonated polyarylene biphenylsulphone di-block-10

The molar ratio is 0.1 and y (1-x) is 0.9. Infrared spectroscopy (FT-IR) analysis of the obtained sulfonated polyarylene biphenylsulfone diisobarb 10 showed that the band of 1064 cm ^-1 , which is expected to be the characteristic band of the sulfuric acid, was increased.

&Lt; Example 4-2 > Manufacture of sulfonated polyarylene biphenylsulfone thermoplastic block-30

The same as the method described in Example 4, wherein the molar ratio is 0.3 and y (1-x) is 0.7. As a result of FT-IR analysis of sulfonated polyarylene biphenyl sulfone sulfone sulfonate block 10, it was confirmed that the band of 1064 cm ^-1 , which is expected as a characteristic band of sulfuric acid, was increased.

&Lt; Example 4-3 > Manufacture of sulfonated polyarylene biphenylsulphone di-block-50

The molar ratio is 0.5 and y (1-x) is 0.5. As a result of FT-IR analysis of sulfonated polyarylene biphenyl sulfone sulfone sulfonate block 10, it was confirmed that the band of 1064 cm ^-1 , which is expected as a characteristic band of sulfuric acid, was increased.

&Lt; Experimental Example 1 > Confirm sulphonation

The results of ¹ H NMR and FT-IR measurements of the block copolymers prepared in Examples 1 and 3 are shown in FIG.

Referring to FIG. 1, changes in the area ratio can be confirmed by changing ¹ H NMR peak due to sulfonation.

&Lt; Experimental Example 2 > Physical Characteristics Analysis

Physical properties of the block copolymers prepared in Examples 4-1 to 4-3 were confirmed and shown in Tables 1 and 2.

The average molecular weight of each block copolymer was determined by gel permeation chromatography after dissolving in DMF and adjusting the viscosity to 0.025M LiBr, and summarized in Table 1.

Item Number average molecular weight
(M _n , g mol ^-1 ) Weight average molecular weight
(M _w , g mol ^-1 ) Maximum average molecular weight
(M _max , g mol ^-1 ) Polydispersity index
(PDI, M _n / M _w ) Polyarylene
Biphenylsulfone is used 16000 38000 68000 2.4 Sulfonated polyarylene biphenyl sulfone ether 10 18000 33000 57000 1.9 Sulfonated polyarylene biphenyl sulfone ether 30 10000 26000 59000 2.5 Sulfonated polyarylene biphenyl sulfone ether 50 19000 54000 97000 2.9

The solubilities of the block copolymers prepared in Examples 4-1 to 4-3 were measured in DMAc, NMP, DMSO, DMF, chloroform, THF, acetone, methanol and water in Table 2 The measurement temperature is (+) very well soluble at room temperature, (+) well soluble, (±) partially soluble, ()

menstruum The sulfonated polyarylene biphenyl sulfone sulfone-10 The sulfonated polyarylene biphenyl sulfone sulphate-30 The sulfonated polyarylene biphenyl sulfone sulphate-50 DMAc ++ ++ ++ NMP ++ ++ ++ DMSO ++ ++ ++ DMF ++ ++ ++ chloroform ± ± + THF ± ± ± Acetone Methanol water

Table 2 shows high solubility in polar organic solvents such as DMAc, NMP, DMSO, and DMF.

&Lt; Experimental Example 3 > Chemical characterization

Chemical characteristics such as ion exchange capacity, water content and ionic conductivity of the sulfonated polyarylene biphenylsulfone sulfonated block copolymer prepared in Examples 4-1 to 4-3 were analyzed and shown in Table 3 .

(1) Measurement of ion exchange capacity

The sulfonated polyarylene biphenylsulfone sulfonated copolymers prepared in Examples 4-1 to 4-3 were immersed in 1 M NaCl for 24 hours, then phenolphthalein as a standard solution was added thereto, and then titrated with 0.01 N NaOH And the ion exchange capacity (IEC) value was calculated.

[Equation 1]

IEC (meqg ^-1 ) = (V _NaOH x C _NaOH ) / W _dry

(V _NaOH is consumption of NaOH standard solution, C _NaOH is concentration of NaOH standard solution, W _dry weight of dried film (g)

(2) Moisture content measurement

The sulfonated polyarylene biphenylsulfone sulfon block copolymers prepared in Examples 4-1 to 4-3 were dried and then dried in water for 24 hours, and the weight change rates were calculated.

&Quot; (2) &quot;

Water content (%) = [(W _wet - W _dry ) / W _dry ] × 100

(W _wet in the above equation (3) is the weight of the wet film, W _dry is the weight of the dried film)

(3) Measurement of ion conductivity

The sulfonated polyarylene biphenylsulfone sulfonated block copolymers prepared in Examples 4-1 to 4-3 were measured for negative ion conductivity by measuring the negative resistance or the bulk resistance using the AC diopter.

&Quot; (3) &quot;

Ion conductivity (?, S cm ^-1 ) = L / (R x T x W)

(Where L is the distance between two electrodes, R is the resistance of the film, T is the thickness of the film, and W is the width of the film)

Item Glass transition temperature
(° C) Moisture content (%) Ion exchange capacity
(meqg ^-1 ) Ion conductivity
(S cm ^-1 ) Polyarylene
Biphenylsulfone is used 174 0 0 0 Sulfonated polyarylene
Biphenyl sulfone di-10 140 9 0.23 37 Sulfonated polyarylene
Biphenylsulfone is a s-30 140 21 0.74 98 Sulfonated polyarylene
Biphenylsulfone s-50 151 31 1.05 184

The water content and ion exchange capacity of Table 3 were measured at room temperature (25 ° C) and the ion conductivity was measured at 100% relative humidity and 60 ° C. It was confirmed that water content, ion exchange capacity and ion conductivity increase with increasing hydrophilic block.

The polyelectrolyte membrane for fuel cells made of the 4,4-bis (4-chlorophenylsulfone) -1,1-biphenyl compound of the present invention increases water content, ion exchange capacity and ionic conductivity as the hydrophilic block increases, There is a possibility.

Claims (12)

A sulfonated biphenyl sulfone copolymer having a conductive functional group represented by the following formula (2)

(Formula 2)
In Formula 2 Y is a single bond, a carbon-carbon the given directly to, -O-, -S-, -N- -C ( = O) -, -S (= O) 2 - represents the, x is 0, ? X? 4, and Z and Z 'represent one ion-exchange group selected from the group consisting of a sulfonic acid group and a phosphoric acid group. In the above formula (1), Ar ₁ is an aromatic compound, and may be any one selected from the following formulas (10-1) to (10-7);

10-1

10-2

10-3

10-4

10-5

10-6

10-7
In the above formula (1), n is an integer of 3? N? 400. A sulfonated biphenyl sulfone block copolymer having a conductive functional group represented by the following formula (1) by reacting the following formula (2) and (3):

(Formula 1)

(Formula 2)

(Formula 3)
Y is a single bond in which carbon and carbon are directly connected to each other, -O-, -S-, or -C (= O) -, -S (= O) ₂ -;
x is 0? X? 4;
Z, Z 'and Z "represent one ion-exchange group selected from the group consisting of a sulfonic acid group and a phosphoric acid group;
Ar ₁ , Ar ₂ , Ar ₃ are The aromatic compound may be any one independently selected from the following formulas (10-1) to (10-7);

10-1

10-2

10-3

10-4

10-5

10-6

10-7
n and m are integers of 3? n and m? 400. 3. The method according to claim 1 or 2, wherein Z, Z 'and Z''in the general formulas (1) and (2) can be an alkylamine or a sulfuric acid salt having a cationic charge, Ion (Na ⁺ ) or potassium ion (K ⁺ ). [3] The method according to claim 1 or 2, wherein the weight average molecular weight of Formula 2 and Formula 3 is 4,000 g / mol to 400,000 g / mol. According to the copolymer of hydrophilic block or the calculation of molecular weight, Copolymer. [Claim 4] The method according to claim 1, wherein the hydrophilic block is a copolymer obtained by subjecting methylene chloride to a sulfonation process using 0.1 to 4M chlorosulfuric acid, and 4,4-bis (4-chlorophenylsulfone) - Preparation of Copolymers Made Using Biphenyl Compounds The process according to claim 2, wherein the reaction is carried out in the presence of potassium carbonate at 135 占 폚 for 3 to 12 hours, removing toluene at 160 占 폚 for 2 hours, supplying energy required for polymerizing at 190 占 폚 Bis (4-chlorophenylsulfone) -1,1-biphenyl compound, which is a block copolymer which is subjected to a reaction temperature for 24 hours or more. The method according to claim 6, wherein the solvent is any one selected from the group consisting of Dimethylacetamide (DMAc), Dimethyl sulfoxide (DMSO), Methylpyrrolidone (NMP), Dimethylformamide (DMF) and Tetrahydrofuran (THF). Preparing a hydrophilic polymer block,
Preparing a sulfonated polyarylene biphenyl sulfone,
(4-chlorophenylsulfone) -1,1-biphenyl compound, which comprises the step of producing sulfonated polyarylene biphenylsulfone as a block copolymer, and a process for producing a polymer electrolyte membrane using the 4,4-bis 11. A polymer electrolyte membrane produced by the method of claim 8, wherein the polymer electrolyte membrane for a fuel cell having a thickness of 4 to 400 m in a dry state A membrane-electrode assembly comprising a polymer electrolyte membrane prepared by the method of claim 8, In a fuel cell,
A fuel cell using a polymer electrolyte membrane for a fuel cell made by using a hydrophilic polymer made by using the 4,4-bis (4-chlorophenylsulfone) -1,1-biphenyl compound of claim 1. In a fuel cell,
A fuel cell using a polymer electrolyte membrane for a fuel cell made by using a block copolymer containing a hydrophilic polymer made by using the 4,4-bis (4-chlorophenylsulfone) -1,1-biphenyl compound of claim 2.

Images