KR101214399B1 - A Ion exchange membrane by pore-filled of porous support membrane and a method of fabricating the same - Google Patents

Abstract

The present invention comprises the steps of: a) preparing a copolymer of dimethyl-5-sulfurisophthalate, diol, isophthalic acid, and maleic anhydride; b) adding dimethyl-5-sulfurisophthalate to the copolymer to prepare a polymer solution. Doing; C) filling the polymer solution into a polymer porous support membrane and curing the polymer solution; It relates to a method for producing an ion exchange membrane comprising a, the ion exchange membrane prepared by the present invention is a high functional ion exchange membrane excellent in ion exchange capacity and hydrogen ion conductivity.

Description

Ion exchange membrane by pore-filled of porous support membrane and a method of fabricating the same}

The present invention relates to a highly functional ion exchange membrane and its preparation method by pore filling of a porous support membrane.

Ion-exchange membranes are selective permeable membranes that can selectively separate anions and cations in water, and are used for diffusion dialysis to recover acids and metal species from fuel cells, pickling waste, ultrapure water production processes, desalination of seawater, and recovery of acids and bases. It is applied to the field of water decomposition electrodialysis.

These ion exchange membranes require various properties. It must have high selectivity and require low permeability of solvents and non-ionic solutes, low resistance to diffusion of selected perions, high mechanical strength and chemical resistance.

Currently used ion exchange membranes include fluorine-based cation exchange membranes (Dupont: Nafion, 7, 8 Gore: Gore-select, Asahi: Aciplex & Flemion, etc.) used in fuel cells, and ion exchange membranes (Tokuyama: CMX & AMX, Asahi: CMV & HJC, etc.), rubber-based polymer (Dais-Analytic: S-SEBS).

Such ion exchange membranes generally use perfluorosulfonic acid polymer membranes having alkylene fluoride in the main chain and sulfonic acid groups at the ends of the vinyl fluoride ether chain (eg, Nafion, Dupont). Produce).

As the perfluorosulfonic acid polymer membrane becomes thicker, dimensional stability and mechanical properties are improved, but the film resistance of the resin film increases, and as the thickness thereof decreases, the resistance of the resin film decreases, but not only the mechanical properties decrease. Fuel gases and liquids that do not react during cell operation pass through the ion exchange membrane, resulting in fuel loss and degrading cell performance.

In particular, the polymer electrolyte membrane has a thickness change of 15 to 30% and a volume change depending on the temperature and degree of hydration in the state of being thermally compressed with the platinum catalyst electrode, and the maximum amount is increased by 3 to 50% by weight of methanol fuel. More than 200% volume change occurs. The increase in thickness due to the swelling of the electrolyte membrane causes stress on the gas diffusion layer serving as the electrode substrate, and the dimensional change in the surface direction causes physical degradation of the interface between the catalyst particles and the electrolyte membrane during long-term operation of the fuel cell.

In order to solve this problem, a method of preparing an ion exchange membrane through irradiation of a support membrane, a method of thinning the membrane, and a method of coating and drying the ion exchange solution to fill pores of the support are described in US Pat. Nos. 5,547,551 and 5,599,614. It is.

However, the method of preparing an ion exchange membrane by irradiating a support membrane has a disadvantage of low ion exchange capacity and hydrogen ion conductivity, and the method of thinning has a disadvantage of excessive methanol crossover through the thin film.

The polymer electrolyte membrane prepared by the method of filling the pores of the support is known to have excellent morphological stability and to effectively control methanol permeation.

However, such a membrane has a disadvantage of low ion conductivity compared to Nafion because of the high price and the application of a nonionic conductive membrane.

The present invention has been made in an effort to provide an ion exchange membrane and a method for preparing the same, which are prepared by filling and curing a solution having an ion exchange ability in a polymer porous support membrane. It is an object of the present invention to provide a method for producing a highly functional ion exchange membrane having excellent ion exchange capacity and hydrogen ion conductivity by filling porous support membrane pores.

The present invention comprises the steps of: a) preparing a copolymer of dimethyl-5-sulfoisophthalate (DMSIP), diol, isophthalic acid, maleic anhydride (MA) ;

b) preparing a polymer solution by adding dimethyl-5-sulfoisophthalate to the copolymer; And

c) filling the polymer solution into a polymer porous support membrane and curing the polymer solution.

The said filling can be made more preferably a casting method. More specifically, the glass plate may be filled by a casting method.

The dimethyl-5-sulfoisophthalate provides ion exchange ability as a monomer having ion exchange ability.

The copolymer prepared in step a) preferably contains 30 to 50% by weight of dimethyl-5-sulfoisophthalate (DMSIP). If the above range is exceeded, the ion exchange membrane is easily broken, and if the content is less than the ion exchange capacity of the prepared ion exchange membrane may be lowered.

More specifically, the diol may use hexanediol (6-Hexanediol: HDO). The nucleic acid diol may be soft considering that dimethyl-5-sulfoisophthalate is hard. The maleic anhydride (MA) may be provided as a link during curing.

In step b), dimethyl-5-sulfoisophthalate (Dimethyl 5-sulfoisophthalate: DMSIP) is characterized in that it comprises 30 to 50 parts by weight based on 100 parts by weight of the copolymer synthesized in step a). In step b), DMSIP is preferably used by dissolving in a solvent. The solvent may be selected from polypropylene glycol monomethyl ether (PM). If the above range is exceeded, the copolymer prepared in step a) is not completely dissolved, and if the range is significantly below the above range, the viscosity of the solution is small so that no membrane is formed, and the ion exchange capacity of the membrane is low.

In step a), the copolymer is a step of polymerizing dimethyl-5-sulfoisophthalate (DMSIP) and hexanediol (6-Hexanediol: HDO);

Two steps of polymerization by adding isophthalic acid (IPA) and maleic anhydride to the polymerization reaction product;

It is a two-step condensation polymerization process. 2 shows the synthesis mechanism of step a).

Hereinafter, an ion exchange membrane manufacturing step will be described in more detail with reference to FIG. 1.

The ion exchange capacity of the ion exchange membrane prepared by adding the isophthalic acid can be surprisingly improved. In addition, it can have excellent hydrogen ion conductivity and ion exchange capacity.

The curing in step c) is characterized in that using pentaerythritol tetraacrylate (PETA). In step c) it can be prepared an ion exchange membrane through the UV curing method.

The present invention also relates to a method for preparing an ion exchange membrane, which is prepared by filling a polymer porous support membrane with a mixed solution of a copolymer having an ion exchange group and a monomer solution having an ion exchange group and curing the same.

The copolymer having an ion exchange group is characterized in that the copolymer of dimethyl-5-sulfoisophthalate, diol, isophthalic acid, maleic anhydride. As the monomer solution having the ion exchange group, dimethyl-5-sulfoisophthalate (DMSIP) may be used.

In the present invention, the polymer porous support membrane is more preferably polyethylene.

The present invention is also prepared by the above method, and the ion exchange membrane prepared according to the present invention provides better hydrogen ion conductivity and ion exchange capacity than conventional ion exchange membranes. An ion exchange membrane having an exchange capacity of 0.170 to 0.524 meq / g, an ion conductivity of 0.007 to 0.039 S / cm, and a thickness of 0.01 to 0.05 cm is provided.

The ion exchange membrane according to the present invention has the effect of producing an ion exchange membrane having a high ion exchange capacity and ion conductivity as compared to the ion exchange membrane by the conventional pore filling.

1 is a schematic diagram of an ion exchange membrane and a method for manufacturing the same according to the present invention.
2 is a condensation polymerization mechanism of a copolymer of dimethyl-5-sulfoisophthalate, diol, isophthalic acid, and maleic anhydride according to the present invention.

Hereinafter, the present invention will be described in more detail with reference to specific examples. However, the present invention is not limited to the following examples, and various modifications or changes can be made within the spirit and scope of the present invention.

[Production Example 1]

a) preparing a copolymer of dimethyl-5-sulfoisophthalate, diol, isophthalic acid, malic anhydride; (DMSIP-HDO- (IPA-MA) synthesis)

DMSIP-HDO- (IPA-MA) synthesis is a two stage condensation polymerization. A four-necked round flask equipped with a stirrer, a cooler, a nitrogen inlet, a sample inlet, and a thermocouple was prepared. In the first step, 275 g of dimethyl-5-sulfoisophthalate (DMSIP) and 550 g of hexanediol (HDO) are added to a polymerization reaction by adding 0.1 g of butyl stannoic acid at 220 ° C. and nitrogen. It was.

 In the second step, the polymerization reaction synthesized in the nitrogen state was lowered to 140 ° C., 100 g of isophthalic acid (IPA) and 100 g of maleic anhydride (MA) were added, and the temperature was raised to 220 ° C. to 0.1 g of hydroquinone. Synthesis was carried out by addition. 1 is a condensation polymerization mechanism of the copolymer DMSIP-HDO- (IPA-MA) of dimethyl-5-sulfoisophthalate, diol, isophthalic acid, and maleic anhydride.

The compound used in Preparation Example 1 and its content are shown in Table 1 below.

Production Example 2 to Production Example 5

The preparation was carried out in the same manner as in Preparation Example 1, but the contents were different, and the used compounds and contents are shown in Table 1 below.

Table 1

[Example 1]

Into 18 g of the copolymer prepared according to Preparation Example 1, 0.99 g of pentaerythritol tetraacrylate (PETA) was added thereto. 40 A polymer solution was prepared by adding 15 g of wt% dimethyl-5-sulfoisophthalate (DMSIP) (the solvent used was polypropylene glycol monomethyl ether (PM)). The polymer solution was filled in a glass plate by casting on a polymer porous support membrane, and then cured using UV.

Compounds and contents used in Example 1 are shown in Table 2 below. And the ion exchange capacity and the hydrogen ion conductivity of the prepared Example 1 is shown in Table 2 below.

[Examples 2 to 25]

Example 1 was carried out in the same manner as in Example 1, but the used compound and content were different, and the rest was performed in the same manner as in Example 1.

Compounds and contents used in Examples 2 to 25 are shown in Table 2 below. The ion exchange capacity and the hydrogen ion conductivity of Examples 2 to 25 were measured, respectively, and are shown in Table 2 below.

[Table 2]

[Comparative Example 1]

Example 1 was carried out in the same manner as in Example 1 except that propylene glycol monomethyl ether (PGME) was used instead of DMSIP.

Compounds and contents used in Comparative Example 1 are shown in Table 3 below. The ion exchange capacity and the hydrogen ion conductivity of Comparative Example 1 were measured, respectively, and are shown in Table 3 below.

[Comparative Examples 2 to 25]

The same procedure as in Comparative Example 1 but the difference in the compound and content, the rest was carried out in the same manner as Comparative Example 1, the difference is shown in Table 3, respectively.

The ion exchange capacity and the hydrogen ion conductivity of Comparative Examples 2 to 25 were measured, respectively, and are shown in Table 3 below.

[Table 3]

Dimethyl 5-sulfoisophthalate (DMSIP)

6-Hexanediol (HDO)

Isophthalic acid (IPA)

Maleic anhydride (MA)

Pentaerythritol tetraacrylate (PETA)

Propylene glycol monomethyl ether (PGME)

Claims (9)

a) preparing a copolymer of dimethyl-5-sulfoisophthalate, hexanediol, isophthalic acid, malic anhydride;
b) preparing a polymer solution by adding dimethyl-5-sulfoisophthalate to the copolymer; And
c) filling the polymer solution into a polymeric porous support membrane to cure;
Ion exchange membrane production method comprising a. The method of claim 1,
The dimethyl-5-sulfoisophthalate in step b) is 30 to 50 parts by weight based on 100 parts by weight of the copolymer synthesized in step a). The method of claim 1,
In step a), the copolymer is a step of polymerizing dimethyl-5-sulfoisophthalate and hexanediol; And
Two steps of polymerization by adding isophthalic acid and maleic anhydride to the polymerization reaction;
Method for producing an ion exchange membrane, characterized in that consisting of. The method of claim 1,
Curing in step c) is the ion exchange membrane manufacturing method using a pentaeric tritol tetra acylate. A method for producing an ion exchange membrane, characterized in that the polymer solution having a copolymer having an ion exchange group and a dimethyl-5-sulfoisophthalate monomer solution is filled into a porous porous support membrane and cured. The method of claim 5,
The copolymer having an ion exchange group is a copolymer of dimethyl-5-sulfoisophthalate, diol, isophthalic acid and maleic anhydride. delete The method according to claim 1 or 5,
The polymer porous support membrane is polyethylene ion exchange membrane manufacturing method. An ion exchange membrane prepared by any one of claims 1 to 6, having an ion exchange capacity of 0.170 to 0.524 meq / g, an ion conductivity of 0.007 to 0.039 S / cm, and a thickness of 0.01 to 0.05 cm. .

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