KR101188267B1 - Anion exchange composite membrane with olefin-based additives and method for preparing the same - Google Patents

Abstract

PURPOSE: An anion-exchanging composite membrane is provided to have excellent chemical resistance, processability, mechanical property and low electrical resistance, to facilitate control of ion exchange capacity and ion conductivity, to have uniform ion exchange distribution. CONSTITUTION: An anion-exchanging composite membrane comprises a vinylbenzyl-based-styrene-based-olefin-based copolymer in which a quaternary ammonium group represented by chemical formula 1 is accepted. The copolymer is supported by a support selected from a group consisting of polyethylene, polypropylene, and polytetrafluoroethylene. The copolymer is obtained by copolymerizing 70-30 weight% of a vinylbenzyl-based monomer, styrene-based monomer, a crosslinking agent, and an initiator, and 30-70 weight% of olefin based additives. [Reference numerals] (AA) Embodiment 1

Description

Anion exchange composite membrane with olefin-based additives and method for preparing the same}

The present invention relates to an anion exchange composite membrane containing an olefin additive and a method for preparing the same, specifically an anion exchange composite membrane comprising a vinyl benzyl-styrene-olefin copolymer having a quaternary ammonium group introduced therein; It relates to a manufacturing method thereof.

Ion-exchange membranes are a type of polymer membrane that can selectively separate anions or cations through electrostatic principles depending on the species of ion-exchangeable groups introduced into the membrane. In the case of commercially used cation exchange membranes, largely acidic sulfonic acid groups (-SO _3- ) and weakly acidic carboxylic acid groups (-COO-) are used as ion exchange groups. The primary ammonium group (-NH3 +) will have an ion exchange group.

The separation process using the ion exchange membrane is capable of relatively high purity separation purification compared to the separation method using distillation or chemical treatment, low energy consumption, simple equipment, low equipment investment cost, and continuous process. Therefore, it is attracting attention as a separate purification process in various industrial fields because of its excellent processing capacity per hour.

Currently, ion exchange membranes are used for electrodialysis, desalination or purification to remove heavy metals or other ionic substances harmful to the human body, water-splitting electrodialysis, and acid recovery from acid waste. It can be applied to industries such as diffusion dialysis, electrodeionization for the production of ultrapure water for semiconductor or power generation through desalination of seawater or surface water, and its applications are also expanding. In general, commercial membranes should have high ion selective permeability (> 0.95-0.98), low electrical resistance (<3.0-4.0 cm 2), adequate water content, high mechanical strength and chemical resistance.

Conventionally, using a copolymer of styrene-divinylbenzene or a styrene-butadiene copolymer as a base material for ion exchange membrane, it was produced by a manufacturing process method such as bulk polymerization method, latex method, paste method.

The bulk polymerization method is a polymerization method which does not use a solvent and polymerizes only monomers or by adding an initiator to the monomers. However, when the bulk polymerization method is polymerized alone with only styrene-divinylbenzene monomer, brittleness is increased and mechanical properties are deteriorated. Therefore, a support that can reinforce mechanical strength should be used. Since there is a need to increase the overall manufacturing cost of the membrane.

In the latex method, a latex of styrene-divinylbenzene or a latex of styrene-butadiene copolymer is deposited on a support and dried, and then a base film is formed through crosslinking by an oxidative crosslinking method, and then sulfonated on the base film. It is a method of introducing an ion exchange group through the reaction, chloromethylation reaction or quaternary amination reaction. However, the latex method has a problem in that the mechanical properties and electrochemical properties of the membrane may be reduced by the influence of the emulsifier remaining in the latex of the polymer.

On the other hand, the paste method is the method used for the production of ion exchange membranes commercialized under the trademark Neosepata (Tokuyama Co. LTd., Japan) or the trademark Selemion (Asahi Glass Company, Japan). It is a method used. The paste method is a method of preparing a paste using vinylbenzyl chloride-divinylbenzene monomer, a powder of a copolymer thereof, a plasticizer and a rubber, and then applying the temperature to a thin cloth, which is a support, to prepare the paste. The mechanical and electrochemical properties are better than those obtained by the law or latex method. However, in order to obtain improved mechanical properties, an additive must be added, and the complexity of the manufacturing process acts as a factor to increase the manufacturing cost of the membrane, and the membrane is broken during drying, and chemical stability is deteriorated ( Y. Mizutani, Structure of ion-exchange membranes, J. Member.Sci. 49 (1990) 121).

Conventionally, Patent Document 1 uses a non-porous low density polyethylene film having both monomer absorbency and photocrosslinkability as a support as a support to absorb vinyl benzyl chloride, swelling promoting monomer, divinylbenzene, and photoinitiator, and then irradiates with ultraviolet rays. And a method of preparing an anion exchange membrane by introducing an anion exchange group through a quaternary amination reaction. However, the ion exchange membrane prepared by the above method has a low strength of the support itself, and there is a difficulty in commercial production due to high brittleness after introduction of the ion exchange group.

In addition, Patent Document 2 discloses a porous film produced by a series of manufacturing processes in which a polymerization film containing a styrene monomer, a vinylbenzyl monomer, a crosslinking agent, and an initiator is impregnated with a porous film to form an introduction of ammonium ions after polymerization. An anion exchange composite membrane containing a styrene-vinylbenzyl copolymer is disclosed. The anion exchange membrane prepared by the above method does not use an additive for improving mechanical strength, and thus there is a problem in terms of physical properties of high strength and high impact resistance.

However, as described above, after the addition of the olefin-based additives to the polymerization solution in which the amination reaction-activated vinylbenzyl monomer, the amination reaction inert styrene monomer, the crosslinking agent and the initiator are mixed, the polymerization solution is fabricated. No invention has been reported for a method of preparing an anion exchange composite membrane by immersing a support in to saturate the inside, performing thermal crosslinking polymerization, and then introducing quaternary ammonium ions.

Accordingly, the present inventors are interested in a method for producing an anion exchange composite membrane having a simple manufacturing process, low manufacturing cost, and excellent conductivity, mechanical strength, and chemical resistance, and the anion exchange composite membrane of the present invention is ion exchanged. Excellent capacity, low electrical resistance, excellent processability, ion exchange capacity and ion by controlling the ratio of polymerization solution composed of styrene monomer, vinyl benzyl monomer, crosslinking agent and initiator and olefin additive The conductivity of the anion exchange membrane is very easy to control, and the use of olefin additives improves the brittleness of the membrane and has an even ion exchange distribution. The present invention was completed by confirming that the chemical properties were excellent.

Patent Document 1: Republic of Korea Patent No. 10-0542295 Patent Document 2: Republic of Korea Patent No. 10-0999048

An object of the present invention is to provide an anion exchange composite membrane having low electrical resistance, excellent ion exchange ability, processability, mechanical properties and chemical resistance, easy control of ion exchange capacity and ion conductivity, improved brittleness of membrane and even ion exchange distribution. To provide.

It is also an object of the present invention to provide a method for producing the anion exchange composite membrane.

In order to achieve the above object,

The present invention is a vinyl benzyl system introduced quaternary ammonium group represented by the formula (1)-

Provided are anion exchange composite membranes comprising a styrene-olefin copolymer:

[Formula 1]

" 은 랜덤 공중합체를 나타낸다).
(In the formula 1, "

"Represents a random copolymer).

In another aspect, the present invention provides a method for producing an anion exchange composite membrane comprising a vinyl benzyl-styrene-olefin copolymer having a quaternary ammonium group represented by the formula (1).

The anion exchange composite membrane including the vinylbenzyl-styrene-olefin-based copolymer having the quaternary ammonium group introduced therein is not only improved in ion exchange capacity, mechanical properties, chemical properties and processability while having low electrical resistance. It is very easy to control ion exchange capacity and ion conductivity.

Figure 1 shows an electron scanning microscope (SEM) photograph of the surface (x 1000) of the anion exchange composite membrane of Example 1 of the present invention.
Figure 2 shows an electron scanning microscope (SEM) photograph of the surface (x 5000) of the anion exchange membrane of Comparative Example 2 prepared by the paste method.

Hereinafter, the present invention will be described in detail.

The present invention provides an anion exchange composite membrane comprising a vinylbenzyl-styrene-olefin-based copolymer having a quaternary ammonium group represented by Formula 1 below:

[Formula 1]

" 은 랜덤 공중합체를 나타낸다).
(In the formula 1, "

"Represents a random copolymer).

In the anion exchange composite membrane represented by Formula 1 of the present invention, the copolymer may be supported by a support. The support may be selected and used without limitation as long as the support is a polymer having excellent mechanical strength and chemical resistance, preferably polyethylene, polypropylene, polytetrafluoroethylene, or the like.

In addition, in obtaining the vinylbenzyl-styrene-olefin-based copolymer constituting the present invention, the styrene-based monomer can be used without limitation as long as it is a known compound including styrene, preferably styrene and alpha. Methyl styrene, vinylpyridine, trifluorostyrene, 2-vinyl pyridium, or the like may be used alone or in combination, and more preferably, a styrene monomer inert to amination reaction may be used.

Furthermore, in the anion exchange composite membrane represented by Chemical Formula 1 of the present invention, the copolymer may include 70 to 30% by weight of a monomer mixture including a vinylbenzyl monomer, a styrene monomer, a crosslinking agent and an initiator, and an olefin additive. Preference is given to copolymerizing 70% by weight. If the content of the olefin-based additive is 30% by weight or less, the effect is not obvious and brittleness is not improved, and when 70% by weight or more, the flexibility of the anion exchange membrane may be excessive, and the strength of the membrane may be remarkably lowered.

The vinylbenzyl monomers impart functional groups capable of introducing an anion exchange group, so that the ion exchange capacity and water content increase as the composition ratio of the copolymer increases. Therefore, in the anion exchange composite membrane of the vinylbenzyl-styrene-olefin-based copolymer of the present invention, the ion exchange capacity and the ion conductivity can be easily adjusted by adjusting the composition of the styrene monomer and the vinyl benzyl monomer.

Furthermore, in obtaining the vinylbenzyl-styrene-olefin-based copolymer constituting the present invention, the olefin additive is added to the vinylbenzyl-styrene-based polymer to solve the problem of adding flexibility to the membrane and increasing brittleness during drying. Any number can be used without limitation, preferably butene, pentene, hexene, heptene, octene, nonene decene and the like can be used alone or in combination, more preferably hexene, pentene, octene or nonene can be used. have.

In addition, the present invention, as shown in Scheme 1 below,

Impregnating a support in the form of a fabric into a polymerization solution comprising a vinylbenzyl monomer of Formula 2, a styrene monomer of Formula 3, an olefin additive of Formula 4, a crosslinking agent of Formula 5 and an initiator (Step 1);

Preparing a vinylbenzyl-styrene-olefin-based copolymer composite membrane of Chemical Formula 6 by polymerizing the vinylbenzyl-based monomer, the styrene-based monomer, and the olefin-based additive in the fabric of the fabric impregnated in step 1 (step 2); And

Comprising the reaction of the tertiary amine to the vinyl benzyl-styrene-olefin copolymer composite membrane of step 2 to introduce a quaternary ammonium group as an anion exchanger to prepare an anion exchange composite membrane of the formula (1) It provides a method for preparing an anion exchange composite membrane represented by the following formula (1):

[Reaction Scheme 1]

" 은 랜덤 공중합체를 나타낸다).
(In the formula 1, "

"Represents a random copolymer).

Hereinafter, a method of preparing the anion exchange composite membrane represented by Chemical Formula 1 will be described in more detail.

First, in the method for producing an anion exchange composite membrane represented by Formula 1, Step 1 is a vinylbenzyl monomer of Formula 2, a styrene monomer of Formula 3, an olefin additive of Formula 4, a crosslinking agent and an initiator of Formula 5 It is a step of impregnating the support in the form of a fabric in the polymerization solution comprising.

Specifically, the polymerization solution of Step 1 is prepared by mixing the vinylbenzyl monomer of Formula 2 and the styrene monomer of Formula 3, the olefin additive of Formula 4, the crosslinking agent of Formula 5 and the initiator. The polymerization solution of step 1 is 70 to 30% by weight of a monomer mixture comprising a vinylbenzyl monomer of Formula 2, a styrene monomer of Formula 3, a crosslinking agent and an initiator of Formula 5, and 30 to 70% by weight of an olefin additive of Formula 4. It is preferable to use a mixture, and the initiator may be included in an amount of 0.1 to 5% by weight based on 100% by weight of the monomer mixture.

In addition, the crosslinking agent of Chemical Formula 5 of Step 1 plays a role in determining the swelling degree and the degree of crosslinking of the final membrane, and may be used without limitation as long as it can crosslink the vinylbenzyl-styrene-olefin-based copolymer. Divinylbenzene can be used.

Further, the initiator of step 1 may be used without limitation as long as it can initiate thermal crosslinking polymerization, preferably N, N'-azobisisobutyronitrile (AIBN), benzoyl peroxide (BPO), Cumyl peroxide, lauroyl peroxide, and the like can be used, and more preferably, N, N'-azobisisobutyronitrile (AIBN) or benzoyl peroxide (BPO) can be used.

In addition, the support of the saturated fabric form of step 1 is a support for a fabric, such as polyethylene, polypropylene, polytetrafluoroethylene in a polymerization solution prepared by mixing a monomer mixed solution and an olefin additive at room temperature for 30 minutes- It can be prepared by impregnation for 24 hours. The saturated fabric-like support fills the pores of the support with the polymerization solution and is plasticized in the course of processing the network structures of the fibers and the spaces between the fibers, so that the mechanical strength and chemical resistance are superior to conventional membranes. And a uniform ion exchange membrane can be prepared.

Next, in the method for preparing an anion exchange composite membrane represented by Chemical Formula 1, Step 2 is obtained by polymerizing a styrene-based monomer, a vinylbenzyl-based monomer, and an olefin-based additive in a cloth-like support impregnated in Step 1 It is a step of preparing a styrene-vinylbenzyl-olefin copolymer composite membrane.

Specifically, the polymerization reaction of step 2 is such that the vinylbenzyl-based monomer of Formula 2, the styrene-based monomer of Formula 3, the olefin-based additive of Formula 4, the crosslinking agent and the initiator of Formula 5 are sufficiently sorbed to the fabric to reach an equilibrium state. The support in the form of fabric should be left in the polymerization solution at room temperature, preferably for 30 minutes-24 hours, more preferably 1-12 hours. Thereafter, the support in which the polymerization solution was sorbed was placed on a square glass plate, covered with another glass plate, and then subjected to polymerization using heat at a temperature of 50-100 ° C. for 8 to 24 hours to form vinylbenzyl of Formula 6 The styrene-olefin-based copolymer composite membrane can be produced. After the polymerization reaction is completed, it is washed several times in an organic solvent such as tetrahydrofuran, dichloroethane, acetone, toluene and the like to remove the unreacted monomer remaining in the membrane.

Next, in the method for producing an anion exchange composite membrane represented by Formula 1, step 3 is a quaternary ammonium group as an anion exchanger by reacting a tertiary amine with the vinylbenzyl-styrene-olefin composite membrane of step 2 It is introduced to prepare an anion exchange composite membrane of the formula (1).

Specifically, as the tertiary amine of step 3, trimethylamine, triethylamine, diphenylethylamine, diethylphenylamine, and the like may be used, and the amine itself or an organic such as ultrapure water, acetone, tetrahydrofuran, or the like may be used. Dilution with a solvent may be performed to react with the styrene-vinylbenzyl-olefin copolymer of step 2. The concentration of the tertiary amine can be used for the reaction without great limitation, but preferably 1 to 50% by weight can be used.

In addition, the reaction between the vinylbenzyl-styrene-olefin-based copolymer and the tertiary amine is carried out by immersing the copolymer membrane in an amine or amine solution for 1 to 36 hours, preferably 12 to 24 hours at room temperature. After the reaction was completed, in order to remove the unreacted amine remaining in the composite membrane, washed several times at room temperature with ultrapure water or an organic solvent, and then immersed in ultrapure water or an organic solvent overnight and washed several times again to introduce a quaternary ammonium group of the formula (1). Prepared anion exchange membrane can be prepared.

Referring to Experimental Example 1, the anion exchange composite membrane represented by Chemical Formula 1 of the present invention has excellent ion exchange capacity, and improves mechanical properties by using a high strength fabric type support, and does not add olefinic additives. Compared with anion exchange membrane, which has low water content, the brittleness is greatly lowered, the strength is improved, and the membrane area resistance is low, the ion conductivity is excellent, and the flexibility of the membrane is increased, thereby improving the overall ion distribution of the membrane. can confirm. Therefore, the method for producing an anion exchange composite membrane of the present invention can be usefully used for the production of an anion exchange composite membrane having low electrical resistance and improved ion exchange ability, mechanical properties, chemical properties and processability.

Hereinafter, the present invention will be described in more detail with reference to the following Examples and Experimental Examples.

However, the following examples and experimental examples are intended to illustrate the contents of the present invention, but the scope of the invention is not limited by the examples and the experimental examples.

< Example  1> Anion Exchange with Olefin Additive Of composite membrane  Manufacturing - 1

Vinylbenzyl chloride: styrene: divinylbenzene in a weight% ratio of 50: 30: 20, and 1, weight% of N, N'-azobisisobutyronitrile (AIBN) as an initiator to 100% by weight of the monomer mixture. A polymerization solution prepared by adjusting the mixture and a 1-hexene olefin additive in a weight ratio of 50:50 were mixed to prepare a polymerization solution. Thereafter, a polyethylene support having a thickness of about 180 μm was immersed in the polymerization solution for 4 hours to be saturated impregnated.

The polyethylene support impregnated with the polymerization solution was placed on a square glass plate and covered with another glass plate and then sealed with a tape to prevent loss of the polymerization solution. The polymerization was carried out in an oven at 65 ° C. for 16 hours. When the polymerization was completed, the membrane was separated from the glass plate, immersed in tetrahydrofuran at room temperature, left for 12 hours, then taken out and immersed in tetrahydrofuran again to remove unreacted monomers several times.

The composite membrane prepared by the polymerization reaction was immersed in a 1: 3 mixed solution of 25% by volume trimethylamine aqueous solution and 75% by volume acetone and aminated at room temperature for 24 hours. After the amination reaction is completed, in order to remove the unreacted trimethylamine remaining in the completed composite membrane, it is washed several times at room temperature with ultrapure water, and then immersed in ultrapure water overnight again several times to remove the quaternary ammonium group (-N ⁺ (R Anion exchange membrane into which ₃ ) was introduced was prepared. In this process, a vinylbenzyl-styrene-based anion exchange composite membrane in which an olefin was added as a support of polyethylene having a total thickness of about 230 μm was prepared, and physical properties were measured according to the physical property measurement method of Experimental Example 1 below. The results are shown in Table 1. In addition, an electron scanning microscope (SEM) photograph of the surface (x 1000) of the anion exchange composite membrane of Example 1 is shown in FIG.

< Example  2> anion exchange with olefin additive Of composite membrane  Manufacturing - 2

Vinylbenzyl chloride: styrene: divinylbenzene in a weight% ratio of 50: 30: 20, and 1, weight% of N, N'-azobisisobutyronitrile (AIBN) as an initiator to 100% by weight of the monomer mixture. A polymerization solution was prepared by mixing the polymerization solution and the olefin additive of 1-pentene in a weight ratio of 40:60. Thereafter, a polypropylene support having a thickness of about 180 μm was immersed in the polymerization solution for 3 hours to allow saturated impregnation.

The polypropylene impregnated with the polymerization solution was placed on a square glass plate and covered with another glass plate and then sealed with a tape to prevent loss of the polymerization solution. The polymerization was carried out in an oven at 65 ° C. for 16 hours. When the polymerization was completed, the membrane was separated from the glass plate, soaked in tetrahydrofuran at room temperature and left for 12 hours, then taken out and soaked again in tetrahydrofuran to remove unreacted monomers several times.

The composite membrane prepared by the polymerization reaction was immersed in a 1: 3 mixed solution of 25 volume% trimethylamine aqueous solution and 75 volume% acetone and aminated at room temperature for 24 hours. After the amination reaction is completed, in order to remove the unreacted trimethylamine remaining in the completed composite membrane, it is washed several times at room temperature with ultrapure water, and then immersed in ultrapure water overnight again several times to remove the quaternary ammonium group (-N ⁺ (R Anion exchange membrane into which ₃ ) was introduced was prepared. In this process, a vinylbenzyl-styrene-based anion exchange composite membrane, in which the total thickness of the membrane was about 230 μm, to which polyolefin was added, was prepared, and the physical properties were measured according to the physical property measurement method of Experimental Example 1 below. The results are shown in Table 1.

< Example  3> Anion exchange with olefin additive Of composite membrane  Manufacturing - 3

A polymerization solution containing vinylbenzyl chloride: styrene: divinylbenzene in a weight% ratio of 50: 30: 20, and adjusted to 2 weight% of benzoyl peroxide (BPO) as an initiator with respect to 100 weight% of the monomer mixture; An olefinic additive of 1-octene was mixed at a weight ratio of 40:60 to prepare a polymerization solution. Thereafter, a polytetrafluoroethylene support having a thickness of about 180 μm was deposited for 4 hours to allow saturated impregnation.

The polytetrafluoroethylene impregnated with the polymerization solution was placed on a square glass plate and covered with another glass plate and then sealed with a tape to prevent loss of the polymerization solution. The polymerization was carried out in an oven at 80 ° C. for 16 hours. When the polymerization was completed, the membrane was separated from the glass plate, immersed in tetrahydrofuran at room temperature, left for 12 hours, then taken out and immersed in tetrahydrofuran again to remove unreacted monomers several times.

The composite membrane prepared by the polymerization reaction was immersed in a 1: 3 mixed solution of 25 volume% trimethylamine aqueous solution and 75 volume% acetone and aminated at room temperature for 24 hours. After the amination reaction is completed, in order to remove the unreacted trimethylamine remaining in the completed composite membrane, it is washed several times at room temperature with ultrapure water, and then immersed in ultrapure water overnight again several times to remove the quaternary ammonium group (-N ⁺ (R Anion exchange membrane into which ₃ ) was introduced was prepared. In this process, a vinylbenzyl-styrene-based anion exchange composite membrane having an olefin-based polytetrafluoroethylene support having a total thickness of about 230 µm was prepared, and the physical properties were measured according to the physical property measurement method of Experimental Example 1 below. Was measured, and the results are shown in Table 1.

< Example  4> Anion Exchange with Olefin Additive Of composite membrane  Manufacturing - 4

A polymer solution containing vinylbenzyl chloride: styrene: divinylbenzene in a weight% ratio of 50:30:20, and adjusted to 2% by weight of benzoyl peroxide (BPO) as an initiator based on 100% by weight of the monomer mixture; An olefinic additive of 1-nonene was mixed in a weight ratio of 30:70 to prepare a polymerization solution. Thereafter, a polytetrafluoroethylene support having a thickness of about 180 μm was deposited for 3 hours to allow saturated impregnation.

The polytetrafluoroethylene impregnated with the polymerization solution was placed on a square glass plate and covered with another glass plate and then sealed with a tape to prevent loss of the polymerization solution. The polymerization was carried out in an oven at 80 ° C. for 16 hours. When the polymerization was completed, the membrane was separated from the glass plate, soaked in tetrahydrofuran at room temperature and left for 12 hours, then taken out and soaked again in tetrahydrofuran to remove unreacted monomers several times.

The composite membrane prepared by the polymerization reaction was immersed in a 1: 3 mixed solution of 25 volume% trimethylamine aqueous solution and 75 volume% acetone and aminated at room temperature for 24 hours. After the amination reaction is completed, in order to remove the unreacted trimethylamine remaining in the completed composite membrane, it is washed several times at room temperature with ultrapure water, and then immersed in ultrapure water overnight again several times to remove the quaternary ammonium group (-N ⁺ (R Anion exchange membrane into which ₃ ) was introduced was prepared. In this process, a vinylbenzyl-styrene-based anion exchange composite membrane having an olefin-based polytetrafluoroethylene support having a total thickness of about 230 µm was prepared, and the physical properties were measured according to the physical property measurement method of Experimental Example 1 below. Was measured, and the results are shown in Table 1.

< Comparative example  1> Anion exchange without olefin additive Of composite membrane  Produce

Anionic exchange composite membrane of Comparative Example 1 was prepared in the same manner as in Example 1, except that the olefinic additive was not used in the preparation of the polymerization solution, and the physical properties thereof were measured according to the measurement method of Experimental Example 1 below. The results are shown in Table 1.

< Comparative example  2> Paste method  Manufactured by

Using a commercially available commercially available membrane (Astom, Japan, CMX, thickness of about 140 ㎛) manufactured by a conventional paste method, the physical properties were measured according to the measurement method of the physical property of Experimental Example 1 below. Table 1 shows. 2, the electron scanning microscope (SEM) photograph of the surface (x 5000) of the anion exchange membrane of the comparative example 2 is shown.

< Experimental Example  1> Of anion exchange membrane  Property measurement

In order to confirm the improved strength of the anion exchange composite membrane including the vinylbenzyl-styrene-olefin-based copolymer having the quaternary ammonium group introduced therein, the anion exchange membranes of Examples 1 to 4 and Comparative Examples 1 and 2 The moisture content of was measured, and the results are shown in Table 1 below. The anion exchange membrane was immersed in ultrapure water for at least 24 hours to sufficiently swell the membrane, then carefully wipe off the surface moisture and measure the increased weight W ₁ (g), which was dried in a vacuum oven at 120 ° C. for 24 hours, and then the dry weight was W ₂ (g) can be measured and the moisture content (%) can be calculated | required by following formula (1).

[Equation 1]

In addition, in order to confirm the ion exchange capacity of the anion exchange composite membrane comprising the vinylbenzyl-styrene-olefin-based copolymer in which the quaternary ammonium group of the present invention is introduced, Examples 1-4 and Comparative Examples 1-2 The ion exchange capacity (IEC) of the anion exchange membrane was measured and the results are shown in Table 1 below. After measuring the dry weight of the anion exchange membrane, the quaternary ammonium group was completely replaced with -N ⁺ (R) Cl ^- form by immersion in 1.0 M NaCl solution for 24 hours. Subsequently, it was again submerged in 0.5 M Na ₂ CO ₃ solution for 24 hours to be substituted with N ⁺ (R) ₃ CO ₃ ^- and potassium dichromate (5%) was added to the solution in an amount of 1 to 3 drops. The amount of AgNO ₃ consumed was measured by titrating Cl ⁻ distributed in the solution with AgNO ₃ until a reddish brown precipitate occurred, and the ion exchange capacity (IEC, unit meq / g) was calculated by Equation 2 below. You can get:

&Quot; (2) &quot;

(In Equation 2, Wy represents the weight of the dried film, V represents the amount of AgNO ₃ consumed, C represents the concentration of AgNO ₃ solution used for titration).

Furthermore, in order to confirm the improved ion conductivity of the anion exchange composite membrane including the vinylbenzyl-styrene-olefin-based copolymer having the quaternary ammonium group introduced therein, Examples 1-4 and Comparative Examples 1-2. The membrane area resistance of the anion exchange membrane was measured, and the results are shown in Table 1 below. Membrane area resistance of the anion exchange membrane can be obtained by the following equation 3 using the impedance value and the phase angle measured by LCZ meter in 0.5 M aqueous NaCl solution.

&Quot; (3) &quot;

(In Equation 3, θ represents a phase angle and Z represents an impedance value.)

division

Example Comparative example Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2

polymerization
solution
ingredient
(weight%) Olefin 100
(1-hexene) 150
(1-pentene) 150
(1-octene) 233
(1-nonene) - - textile
Support Poly
Ethylene Poly
Propylene Polytetrafluoroethylene Polytetrafluoroethylene Poly
Ethylene - Styrene 30 30 30 35 30 - Vinylbenzyl
Chloride 50 50 50 45 50 -


Properties
Ion exchange capacity
(meq./g) 3.9 3.5 3.7 3.2 3.7 2.4 Moisture content
(%) 26 23 22 18 46 25 Membrane area resistance
(Ω㎠) 2.6 2.8 2.7 3.0 3.7 3.6

As shown in Table 1, the anion exchange composite membranes of Examples 1 to 4 in which olefins were used to prepare a polymerization solution were compared with Comparative Example 1 without using olefins and Comparative Example 2, which are commercial membranes.

As a result, it was confirmed that the anion exchange composite membrane of Examples 1 to 4 of the present invention had improved mechanical properties than the membranes of Comparative Examples 1 to 2 by using a high strength fabric type support. Furthermore, compared with the anion exchange composite membrane of Comparative Examples 1-2 without the addition of the olefinic additive, the brittleness was greatly lowered due to the low water content and the strength was improved.

In addition, the anion exchange composite membranes of Examples 1 to 4 of the present invention have no significant difference in ion exchange capacity associated with the function of the anion exchange membrane compared to Comparative Example 1, but excellent ion exchange compared to the membrane prepared by the conventional paste method. The dose is shown.

Furthermore, the anion exchange composite membranes of Examples 1 to 4 of the present invention have a low membrane area resistance, which not only improves ionic conductivity, but also increases flexibility of the membrane, thereby improving the overall ion distribution of the membrane, thereby having a homogeneous effect. can confirm. It is also found that the thickness of the anion exchange composite membranes of Examples 1 to 4 is 230 μm, which is much lower than that of the commercial membrane AMX of Comparative Example 2, which is about 140 μm thick. Can be.

In addition, referring to Figures 1 and 2 it can be confirmed that a homogeneous anion exchange composite membrane is prepared because the support of the fabric form of the anion exchange composite membrane of Example 1 of the present invention is completely filled with a resin and no phase separation and pinholes are found. .

Therefore, the method for preparing an anion exchange composite membrane including the vinylbenzyl-styrene-olefin-based copolymer in which the quaternary ammonium group is introduced according to the present invention has low electrical resistance and has ion exchange ability, mechanical properties, chemical properties, and processability. It can be usefully used for the production of this improved anion exchange composite membrane.

Claims (12)

An anion exchange composite membrane comprising a vinylbenzyl-styrene-olefin copolymer having a quaternary ammonium group represented by Formula 1 introduced therein:
[Formula 1]

(In the formula 1, "

"Represents a random copolymer).
The method of claim 1,
The copolymer is an anion exchange membrane, characterized in that supported by any one support selected from the group consisting of polyetherene, polypropylene and polytetrafluoroethylene.
The method of claim 1,
The copolymer is an anion exchange composite membrane obtained by copolymerizing 70-30 wt% of a monomer mixture comprising vinylbenzyl monomer, styrene monomer, crosslinking agent and initiator and 30-70 wt% of olefinic additive.
The method of claim 3,
An anion exchange composite membrane, characterized in that the initiator comprises 0.1 to 5 parts by weight based on 100 parts by weight of the monomer mixture.
The method of claim 3,
The vinyl benzyl monomer is an anion exchange composite membrane, characterized in that one or two or more selected from the group consisting of vinyl benzyl chloride, vinyl benzyl bromide and vinyl benzyl iodide.
The method of claim 3,
The styrene monomer is an anion exchange composite membrane, characterized in that one or a mixture of two or more selected from the group consisting of alphamethylstyrene, vinylpyridine, trifluorostyrene and 2-vinyl pyridium.
The method of claim 3, wherein
The olefin additive is an anion exchange composite membrane, characterized in that at least one selected from the group consisting of butene, pentene, hexene, heptene, octene nonene and decene.
As shown in Scheme 1 below,
Impregnating a support in the form of a fabric into a polymerization solution comprising a vinylbenzyl monomer of Formula 2, a styrene monomer of Formula 3, an olefin additive of Formula 4, a crosslinking agent of Formula 5 and an initiator (Step 1);
Preparing a vinylbenzyl-styrene-olefin-based copolymer composite membrane of Chemical Formula 6 by polymerizing the vinylbenzyl-based monomer, the styrene-based monomer, and the olefin-based additive in the fabric of the fabric impregnated in step 1 (step 2); And
Preparing a anion exchange composite membrane of Chemical Formula 1 by introducing a quaternary ammonium group into an anion exchanger by reacting a tertiary amine with the vinylbenzyl-styrene-olefin copolymer composite membrane of step 2 (step 3);
Method for producing an anion exchange composite membrane represented by the formula (1) comprising:
[Reaction Scheme 1]

(In the formula 1, "

"Represents a random copolymer).
9. The method of claim 8,
The polymerization solution of step 1 is prepared an anion exchange composite membrane, characterized in that 70 to 30% by weight of a monomer mixture comprising a vinyl benzyl monomer, a styrene monomer, a crosslinking agent and an initiator and 30 to 70% by weight of an olefin additive Way.
9. The method of claim 8,
The initiator of step 1 is N, N'-azobisisobutyronitrile (AIBN), benzoyl peroxide (BPO), cumyl peroxide or lauroyl peroxide method for producing an anion exchange composite membrane.
9. The method of claim 8,
The polymerization reaction of step 2 is a method for producing an anion exchange composite membrane, characterized in that carried out for 8 to 24 hours at a temperature of 50-100 ℃.
9. The method of claim 8,
The tertiary amine of step 3 is trimetal amine, triethylamine, diphenylethylamine or diethylphenylamine method for producing an anion exchange composite membrane.

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