KR101086073B1 - Polyurea porous materials-polyimide composite membrane and method for fabricating the same - Google Patents

Abstract

Provided are a polyurea porous body-polyimide composite membrane and a method of manufacturing the same. The polyurea porous-polyimide composite membrane includes a polyimide matrix and a polyurea porous body dispersed in the polyimide matrix. Polyurea porous body-polyimide composite membrane manufacturing method comprises the steps of preparing a polyurea porous body solution and a polyamic acid solution, mixing the polyurea porous body solution and the polyamic acid solution and applying a mixed solution on the substrate And then heat treating. According to the present invention, by forming a polyurea porous body using a monomer having a tetrahedral structure and introducing the same into a polyimide matrix, a porous-polymer composite membrane having excellent chemical resistance, heat resistance, durability, and permeability can be prepared. Can be. In addition, a polyurea porous body may be introduced into a polyamic acid serving as a polyimide precursor to improve workability and dispersibility.

Description

Polyurea porous materials-polyimide composite membrane and method for fabricating the same

The present invention relates to a porous-polymer composite membrane and a method for producing the same, and more particularly, to a polyurea porous-polyimide composite membrane and a method for producing the same.

In general, membranes can be roughly divided into porous and non-porous. Among them, porous membranes with large pores have a good permeability, but have a very low separation selectivity. Non-porous membranes have a very high selectivity for specific liquids and gases, but have a low permeability. Therefore, various researches using nanoporous materials are in progress to solve these disadvantages and to improve the performance of the membrane. Polymer nanocomposites are composites in which polymer, inorganic or metal particles of 1 to 100 nanometers in size are dispersed in a polymer resin, and have excellent physical properties as well as thermal stability, flame retardancy, liquid and gas permeability, etc. as compared with conventional plastic materials. Attention has been paid in that it can have a high selectivity depending on the size of the pores and the physical properties of the pores. Although many studies have been conducted on porous polymer structures among the porous materials used in the nanocomposite membranes, most organic materials synthesized up to now do not have constant pores or exhibit low mechanical strength. It is difficult to obtain a uniform dispersion system of nanoparticles, and the workability in various forms is also low, which is limited by its practical application. Therefore, a composite membrane having a stable pore size and a large specific surface area and stable dispersion of nanoparticles, and having a suitable mechanical strength, thermal stability, chemical resistance and processability for various applications will be required and a method of manufacturing the same. .

The technical problem to be solved by the present invention is to provide a polyurea porous-polyimide composite membrane having excellent chemical resistance, heat resistance, durability and permeability.

Another technical problem to be solved by the present invention is to provide a method for producing a polyurea porous-polyimide composite membrane which can improve the dispersibility of the polymeric porous body based on high processability.

One aspect of the present invention to achieve the above technical problem provides a polyurea porous-polyimide composite membrane. The composite membrane includes a polyimide matrix and a polyurea porous body contained in the polyimide matrix.

The polyimide may be formed by reaction of a diamine monomer and a monomer of dianhydride.

The polyurea porous body may be formed by polymerization of a monomer represented by Formula 1 below and a monomer having 2 to 4 isocyanate groups or by polymerization of a monomer represented by Formula 2 below and a monomer having 2 to 4 amino groups. have.

<Formula 1>

Wherein X is a carbon atom or a silicon atom

<Formula 2>

Wherein X is a carbon atom or a silicon atom

The polyurea porous body-polyimide composite membrane may be a microporous composite membrane in which the polyurea porous body is evenly dispersed in the polyimide matrix.

The polyurea porous body-polyimide composite membrane may include nanochannels formed by percolation of the polyurea porous body.

Another aspect of the present invention to achieve the above technical problem provides a method for producing a polyurea porous-polyimide composite membrane. The method includes preparing a polyurea porous solution and a polyamic acid solution, mixing the polyurea porous solution and the polyamic acid solution, and applying the mixed solution onto a substrate and then performing heat treatment. do.

The preparing of the polyurea porous solution may include (a) mixing a solution in which a monomer represented by Formula 1 is dissolved and a solution in which monomers having 2 to 4 isocyanate groups are dissolved or a monomer represented by Formula 2 are dissolved. Mixing the prepared solution and a solution in which monomers having 2 to 4 amino groups are dissolved, and (b) reacting the mixed solution under a nitrogen atmosphere.

<Formula 1>

Wherein X is a carbon atom or a silicon atom

<Formula 2>

Wherein X is a carbon atom or a silicon atom

In addition, the preparing of the polyurea porous body solution is performed after the step (b), (c) quenching the reaction solution with water, heating and adding to the non-solvent to form a precipitate and (d) The precipitate may be further washed and dried, and then dispersed in a solvent.

The preparing of the polyamic acid solution may include mixing a diamine monomer and a dianhydride monomer on a solution and reacting the mixed solution under normal temperature and nitrogen atmosphere.

The concentration of the polyamic acid solution may be 10 to 20 wt / vol%.

According to the present invention as described above, by forming a polyurea porous body using a monomer having a tetrahedral structure and introducing it into the polyimide matrix, a porous-polymer having excellent chemical resistance, heat resistance, durability and permeation characteristics Composite membranes can be prepared. In addition, a polyurea porous body may be introduced into a polyamic acid serving as a polyimide precursor to improve workability and dispersibility.

However, the effects of the present invention are not limited to the above-mentioned effects, and other effects not mentioned will be clearly understood by those skilled in the art from the following description.

1 is a flow chart showing a method for producing a polyurea porous body-polyimide composite membrane according to an embodiment of the present invention.
Figures 2a and 2b respectively show the structure of one particle of the polyurea porous body that can be prepared according to an embodiment of the present invention.
3 is a schematic diagram of a case where the polyurea porous bodies are connected to each other to form a nanochannel structure.
4 is an SEM cross-sectional image of the polyurea porous-polyimide composite membrane prepared according to Preparation Example 1. FIG.
5 is an AFM image of a polyurea porous body-polyimide composite membrane prepared by Preparation Example 2. FIG.
6A and 6B are SEM surface images and SEM cross-sectional images of the polyurea porous body-polyimide composite membrane prepared according to Preparation Example 2, respectively.
7 is an SEM cross-sectional image of the polyurea porous body-polyimide composite membrane prepared according to Preparation Example 3.
8 is an AFM image of a polyurea porous body-polyimide composite membrane prepared according to Preparation Example 4.
9A and 9B are SEM surface images and SEM cross-sectional images of the polyurea porous body-polyimide composite membrane prepared according to Preparation Example 4, respectively.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described herein but may be embodied in other forms. Rather, the embodiments disclosed herein are provided so that the disclosure can be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In the following description of the present invention, detailed descriptions of well-known functions or configurations will be omitted if it is determined that the detailed description of the present invention may unnecessarily obscure the subject matter of the present invention.

1 is a flowchart illustrating a method of manufacturing a polyurea porous body-polyimide composite membrane according to an embodiment of the present invention.

Referring to FIG. 1, a polyurea porous solution and a polyamic acid solution are prepared, respectively (S10 and S12). Preparing the polyurea porous solution may include preparing a polyurea porous solution. The preparing of the polyurea porous solution may include (a) a solution in which a monomer [tetra (4-aminophenyl) methane or tetra (4-aminophenyl) silane] is dissolved and 2 to 4 isocyanates (isocyanate, -NCO) a solution in which the monomer having a group dissolved is mixed, or a monomer represented by the formula (2) [tetra (4-isocyanatophenyl) methane or tetra (4-isocyanatophenyl) silane] is dissolved Mixing a solution and a solution in which monomers having 2 to 4 amino (amino, -NH ₂ ) groups are dissolved, and (b) reacting the mixed solution under a nitrogen atmosphere.

<Formula 1>

Wherein X is a carbon atom or a silicon atom

<Formula 2>

Wherein X is a carbon atom or a silicon atom

The monomer having 2 to 4 isocyanate groups may be, for example, a C 1 to C 20 aliphatic compound substituted with 2 to 4 isocyanate groups or a C 6 to C 30 aromatic compound substituted with 2 to 4 isocyanate groups, and 2 to 4 Monomer having one amino group may be, for example, an aliphatic compound of C1 to C20 substituted with 2 to 4 amino groups or an aromatic compound of C6 to C30 substituted with 2 to 4 amino groups. In addition, the C1 to C20 aliphatic compound substituted with the two isocyanate groups or the C1 to C20 aliphatic compound substituted with the two amino groups may be, for example, a compound represented by Formula 3 below.

<Formula 3>

(Wherein R is all isocyanate groups or all amino groups, and n is an integer of 2 to 6)

The aromatic compound of C6 ~ C30 substituted with 2 to 4 isocyanate groups and the aromatic compound of C6 to C30 substituted with 2 to 4 amino groups are selected from the group consisting of compounds represented by the following Chemical Formulas 4 to 10 At least one of which may be.

<Formula 4>

<Formula 5>

<Formula 6>

<Formula 7>

<Formula 8>

<Formula 9>

<Formula 10>

(Wherein R is all isocyanate groups or all amino groups)

That is, the mixed solution commonly includes a monomer having an amino group and a monomer having an isocyanate group capable of forming urea by a polymerization reaction, and at least one of the monomer having the amino group and the monomer having the isocyanate group is It is a monomer having a reactor at the end of a tetrahedral molecular structure. The amount of the monomer to be mixed is preferably selected in an appropriate stoichiometric molar ratio so that the amino and isocyanate groups present in the mixed solution can sufficiently react with each other. For example, when tetra (4-aminophenyl) methane and 1,4-diisocyanatobenzene are mixed, they may be mixed in a molar ratio of 1: 2, and tetra (4-aminophenyl) methane and tetra (4-iso). When cyanatophenyl) methane is mixed, it may be mixed in a molar ratio of 1: 1.

In addition, by reacting the mixed solution under a nitrogen atmosphere, it is possible to suppress side reactions caused by moisture in the air and to cause a polymerization (and crosslinking) reaction only between monomers. The reaction can be understood as a mechanism in which polymerization occurs by nucleophilic addition reaction between the amino group and the isocyanate group of each monomer, and crosslinking reaction occurs by nucleophilic addition reaction between the produced polymers. However, since the crosslinking reaction is performed by the same mechanism as the polymerization reaction, each step of the polymerization and the crosslinking reaction is not clearly distinguished, and may occur simultaneously in the process of forming the polyurea porous body. In this case, gelation of the mixed solution proceeds as the degree of polymerization or crosslinking degree of the polyurea to be formed increases, and in this process, the polyurea undergoes fine particle states having micropores (the state before the gelation of the mixed solution). It may be formed of a material in the bulk semi-solid or solid state (gelling state of the mixed solution). Here, since the gelation rate of the mixed solution depends on the concentration of the mixed monomer, it is possible to form a particulate porous body by appropriately adjusting the concentration of the mixed solution when forming the polyurea porous body.

The polyurea porous body formed in the solution phase by the above method may have a particulate structure as shown in FIG. 2A. In addition, as shown in FIG. 2A, the unreacted (not used for urea bond) amino group and isocyanate group may exist in the polyurea porous body prepared by the above method.

In addition, the step of preparing a porous polyurea solution is performed after the step (b) (that is, the step of reacting the mixed solution under a nitrogen atmosphere), (c) the reaction solution is quenched with water and heated and then the non-solvent Forming a precipitate by adding to and (d) washing and drying the precipitate may further comprise the step of dispersing in a solvent. The non-solvent is a material capable of precipitating the polyurea porous body present in the form of fine particles in the mixed solvent, and for example, acetone may be used. The polyurea porous body prepared through this additional step may have a particulate structure as shown in FIG. 2B. In this case, unlike the structure shown in FIG. 2A, only an amino group is present in the polyurea porous body, which is a result of converting an isocyanate group existing in the polyurea porous body into an amino group through step (c).

The polyurea porous body used in this embodiment has a three-dimensional polymer network structure connected by strong covalent bonds around the tetrahedral structure monomer as a kind of crosslinking point. Namely, tetraphenylmethane derivative [tetra (4-aminophenyl) methane or tetra (4-isocyanatophenyl) methane] or tetraphenylsilane derivative [tetra (4-aminophenyl) silane or tetra (4-isocyanatophenyl Polysilanes that have been polymerized and crosslinked three-dimensionally around silane] can form numerous micropores to form porous bodies having huge specific surface areas. In addition, it may have excellent chemical resistance, heat resistance and durability due to high crosslinking rate and strong covalent bonds.

Preparing the polyamic acid solution (S12) may include preparing a polyamic acid solution. The preparing of the polyamic acid solution may include mixing a diamine monomer and a dianhydride monomer on a solution, and reacting the mixed solution under a room temperature nitrogen atmosphere. The diamine monomer may be at least one selected from the following first compound group, and the dianhydride monomer may be at least one selected from the following second compound group. As the solvent of the mixed solution, a polar aprotic solvent such as DMAc, NMP, DMSO, DMF, or the like may be used.

<1st compound group>

,

,

,

,

,

,

<Second compound group>

,

,

,

,

,

,

,

,

,

,

,

,

When the diamine and dianhydride are mixed, a polyamic acid serving as a polyimide precursor is formed by a nucleophilic reaction between the amino group of the diamine and the carbonyl group of the dianhydride. For example, 4,4'-oxydianiline (ODA) and pyromellitic dianhydride (PMDA) as diamine monomers and dianhydride monomers, respectively, as shown in Scheme 1 below. ) Can be used to form polyamic acid.

<Scheme 1>

The concentration of the polyamic acid solution is preferably adjusted to 10 to 20wt / vol%. When the concentration of the polyamic acid solution exceeds 20wt / vol%, the dispersibility of the polyurea porous body may be reduced during mixing with the polyurea porous solution due to the high viscosity, and the polyurea porous This is because it may be difficult to form a uniform film in the process of applying the mixed solution on the substrate after mixing with the sieve. In addition, when the concentration of the polyamic acid solution is less than 10wt / vol%, it is difficult to control the thickness of the finally obtained polyurea porous-polyimide composite membrane due to the too low concentration, and there may be a problem that the mechanical properties of the membrane is inferior Because.

The prepared polyurea porous solution and the polyamic acid solution are mixed (S14). In the process of mixing the polyurea porous solution and the polyamic acid solution, the polyurea porous body is evenly formed by the interaction between the functional group (amino or isocyanate group) present in the polyurea porous body and the functional group present in the polyamic acid. Can be dispersed. On the other hand, the interaction between the polyurea porous body may occur, so that percolation of the polyurea porous body may occur, thereby forming nanochannels having a structure in which the polyurea porous bodies are connected to each other. 3 is a schematic diagram of a case where the polyurea porous bodies are connected to each other to form a nanochannel structure. If the polyurea porous body has the structure of FIG. 2A when the percolation occurs, covalent bonds between the porous bodies by the functional groups present in the polyurea porous body (ie, present in the amino group and other porous bodies present in any one porous body) Urea bond formed by the reaction of an isocyanate group) to form a nanochannel to which the polyurea porous body is connected. In addition, when the polyurea porous body has the structure shown in FIG. 2B (when the isocyanate group of the porous body is not converted to an amino group to form a covalent bond between the porous bodies), the interaction between the porous bodies (van der Waals attraction, etc.) Percolation may occur due to physical coupling. The formation and extent of nanochannels by the percolation can be controlled by controlling the composition ratio of the polyurea porous body and the polyamic acid and the properties of the polyurea porous body (covalent or physical bonding between the porous bodies). have. As such, the nanochannel formed by the percolation of the porous body can provide a passage through which fluid can flow in the finally formed membrane, and can improve the permeation characteristics of the membrane.

Referring back to FIG. 1, a mixed solution of the polyurea porous body solution and the polyamic acid solution is applied onto a substrate and then thermally treated (S16). The method of applying the mixed solution may be performed by a method appropriately selected in consideration of the viscosity of the mixed solution, such as spin coating, dip coating, casting, or a doctor blade. Can be done. The heat treatment may be performed at a temperature above which an amide group of the polyamic acid and a carboxylic acid group may react to form an imide bond. As a result, a polyurea porous body-polyimide composite membrane having a structure in which a polyamic acid is converted into a polyimide and finally a polyurea porous body is contained in a polyimide matrix can be obtained. The polyurea porous body-polyimide composite membrane may be, for example, a microporous composite membrane in which the polyurea porous body is evenly dispersed in the polyimide matrix. In addition, the polyurea porous body-polyimide composite membrane may include nanochannels formed by percolation of the polyurea porous body.

As described above, according to the present invention, by using a polyurea porous body which exists in a solution state and has excellent processability, the composite membrane can be formed in a suitable form suitable for the purpose of application by a simple method. In addition, there is an advantage in that a polyurea porous-polyimide composite membrane having improved stability, dispersibility, permeability, and the like may be prepared based on the excellent physical properties of the polyurea porous body.

Hereinafter, preferred examples are provided to aid the understanding of the present invention. However, the following experimental examples are only for helping understanding of the present invention, and the present invention is not limited to the following experimental examples.

<Manufacture example 1>

Polyurea Porous body  Preparation of the solution

Tetra (4-aminophenyl) methane (MW: 382.50, 0.232g, 0.607mmol) was dissolved in DMF (N, N-dimethylformide) to prepare an organic solution having a concentration of 4% (wt / vol). Socyanatohexane (MW: 168.19, 0.204 g 1.214 mmol) was dissolved in DMF to prepare an organic solution having a concentration of 4% (wt / vol). Then, tetra (4-aminophenyl) methane solution was slowly added to the 1,6-diisocyanatohexane solution and mixed. The mixed solution was reacted at room temperature under a nitrogen atmosphere for 24 hours to prepare a porous polyurea solution.

Polyamic acid  Preparation of the solution

0.005 mol of 4,4′-oxydianiline was added to a DMAc solvent and stirred for about 30 minutes until it dissolved completely. Next, 0.005 mol of pyromellitic dianhydride was slowly administered to the solution. After reacting for 3 hours at room temperature under a nitrogen atmosphere, a polyamic acid solution of 15% (wt / vol) was prepared.

Polyurea Porous body Polyimide Of composite membrane  Produce

The polyurea porous solution and the polyamic acid solution were mixed so that the polyurea porous solution was present at 10v / v%, and the mixed solution was sufficiently stirred. Next, the mixed solution was cast on a glass plate and heat-treated at 100 ° C., 200 ° C., and 300 ° C. for one hour to finally prepare a polyurea porous-polyimide composite membrane.

4 is an SEM cross-sectional image of the polyurea porous body-polyimide composite membrane prepared according to Preparation Example 1.

Referring to FIG. 4, it can be seen that the polyurea porous body having a diameter of about 30 nm to 40 nm is uniformly dispersed in the polyimide matrix.

<Manufacture example 2>

The polyurea porous solution and the polyamic acid solution were prepared by the same method as described in Preparation Example 1 above.

The polyurea porous solution and the polyamic acid solution were mixed so that the polyurea porous solution was present at 15v / v%, and the mixed solution was sufficiently stirred. Next, the mixed solution was cast on a glass plate and heat-treated at 60 ° C. for 2 hours and at 100 ° C., 200 ° C., and 300 ° C. for 1 hour to finally prepare a porous polyurea-polyimide composite membrane.

5 is an AFM image of the polyurea porous body-polyimide composite membrane prepared according to Preparation Example 2.

6A and 6B are SEM surface images and SEM cross-sectional images of the polyurea porous body-polyimide composite membrane prepared according to Preparation Example 2, respectively.

5 and 6A, it can be seen that the polyurea porous body having a diameter of about 30 nm to 40 nm is uniformly dispersed in the polyimide matrix.

Referring to FIG. 6B, it can be seen that nanochannels are formed in the polyimide matrix by percolation by the interaction between the polyurea porous bodies (covalent bonds formed between the polyurea porous bodies having the structure of FIG. 2A).

<Manufacture example 3>

Polyurea Porous body  Preparation of the solution

The preparation process of the porous polyurea solution of Preparation Example 1 was carried out as it was, but the mixed solution was allowed to react for 24 hours at room temperature and nitrogen atmosphere, the reaction solution was quenched with water, heated to 80 ℃ and slowly precipitated in acetone. The precipitate was washed three times or more with a large amount of acetone and then dried in vacuo at 150 ° C. for three days to obtain a particulate polyurea porous body. The polyurea porous solution was prepared by uniformly dispersing the particulate polyurea porous body in a DMAc solvent.

Polyamic acid  Preparation of the solution

The polyamic acid solution of Preparation Example 1 was carried out as it was to prepare a polyamic acid solution.

Polyurea Porous body Polyimide Of composite membrane  Produce

The polyurea porous solution and the polyamic acid solution were mixed so that the polyurea porous solution was present at 10v / v%, and the mixed solution was sufficiently stirred. Next, the mixed solution was cast on a glass plate and thermally cured at 100 ° C., 200 ° C., and 300 ° C. for 1 hour to finally prepare a polyurea porous-polyimide composite membrane.

7 is a SEM cross-sectional image of the polyurea porous-polyimide composite membrane prepared according to Preparation Example 3.

Referring to FIG. 7, it can be seen that the polyurea porous body having a diameter of about 60 nm to 70 nm is uniformly dispersed in the polyimide matrix.

&Lt; Preparation Example 4 &

A polyurea porous solution and a polyamic acid solution were prepared by the same method as described in Preparation Example 3 above.

The polyurea porous solution and the polyamic acid solution were mixed so that the polyurea porous solution was present at 15v / v%, and the mixed solution was sufficiently stirred. Next, the mixed solution was cast on a glass plate and heat-treated at 60 ° C. for 2 hours and at 100 ° C., 200 ° C., and 300 ° C. for 1 hour to finally prepare a porous polyurea-polyimide composite membrane.

8 is an AFM image of the polyurea porous body-polyimide composite membrane prepared according to Preparation Example 4.

9A and 9B are SEM surface images and SEM cross-sectional images of the polyurea porous body-polyimide composite membrane prepared according to Preparation Example 4, respectively.

8 and 9A, it can be seen that the polyurea porous body having a diameter of about 60 nm to 70 nm is uniformly dispersed in the polyimide matrix.

Referring to FIG. 9B, it can be seen that nanochannels are formed in the polyimide matrix by percolation by the interaction between the polyurea porous bodies (physical bonds formed between the polyurea porous bodies having the structure of FIG. 2B).

In the above, the present invention has been described in detail with reference to preferred embodiments, but the present invention is not limited to the above embodiments, and various modifications and changes by those skilled in the art within the spirit and scope of the present invention. You can change it.

Claims (17)

Polyimide matrix; And
Polyurea porous-polyimide composite membrane comprising a polyurea porous body contained in the polyimide matrix. The method of claim 1,
The polyimide is a polyurea porous-polyimide composite membrane formed by the reaction of a diamine monomer and a monomer of dianhydride. The method of claim 2,
The diamine monomer is at least one selected from the following first compound group, and the dianhydride monomer is at least one selected from the following second compound group: Polyurea porous-polyimide composite membrane:
<1st compound group>

,

,

,

<Second compound group>

,

,

,

,

,

,

The method of claim 1,
The polyurea porous body is formed by polymerization of a monomer represented by the following formula (1) and a monomer having 2 to 4 isocyanate groups or by polymerization of a monomer represented by the following formula (2) and a monomer having 2 to 4 amino groups Phosphorus Polyurea Porous-Polyimide Composite Membrane:
<Formula 1>

Wherein X is a carbon atom or a silicon atom.
<Formula 2>

Wherein X is a carbon atom or a silicon atom. The method of claim 4, wherein
The monomer having 2 to 4 isocyanate groups is a C1 to C20 aliphatic compound substituted with 2 to 4 isocyanate groups or a C6 to C30 aromatic compound substituted with 2 to 4 isocyanate groups, and the monomer having 2 to 4 amino groups. Is a C1 to C20 aliphatic compound substituted with 2 to 4 amino groups or a C6 to C30 aromatic compound substituted with 2 to 4 amino groups. The method of claim 5,
The C1-C20 aliphatic compound substituted with the two isocyanate groups or the C1-C20 aliphatic compound substituted with the two amino groups is a compound represented by the following formula (3),
<Formula 3>

(Wherein R is all isocyanate groups or all amino groups, and n is an integer of 2 to 6)
At least any one selected from the group consisting of C6 to C30 aromatic compounds substituted with 2 to 4 isocyanate groups and C6 to C30 aromatic compounds substituted with 2 to 4 amino groups One Polyurea Porous-Polyimide Composite Membrane:
<Formula 4>

<Formula 5>

<Formula 6>

<Formula 7>

(8)

&Lt; Formula 9 >

<Formula 10>

(Wherein R is all isocyanate groups or all amino groups) The method of claim 1,
The composite membrane is a polyurea porous body-polyimide composite membrane, wherein the polyurea porous body is a microporous composite membrane evenly dispersed in the polyimide matrix. The method of claim 1,
The composite membrane is a polyurea porous-polyimide composite membrane comprising a nanochannel formed by the percolation of the polyurea porous body. The method of claim 8,
The percolation is a polyurea porous-polyimide composite membrane by covalent bonds between the porous bodies by functional groups present in the polyurea porous body or by physical bonding by interaction between the porous bodies. Preparing a polyurea porous solution solution and a polyamic acid solution;
Mixing the polyurea porous solution and the polyamic acid solution; And
Polyurea porous-polyimide composite membrane manufacturing method comprising the step of applying the mixed solution on a substrate and then heat treatment. The method of claim 10, wherein preparing the polyurea porous solution
(a) Mixing the solution in which the monomer represented by the following formula (1) is dissolved and the solution in which the monomer having 2 to 4 isocyanate groups are dissolved or the solution having the monomer represented by the following formula (2) and the monomer having 2 to 4 amino groups Mixing the dissolved solution; And
(B) a method for producing a polyurea porous body-polyimide composite membrane comprising the step of reacting the mixed solution under a nitrogen atmosphere:
<Formula 1>

Wherein X is a carbon atom or a silicon atom.
<Formula 2>

Wherein X is a carbon atom or a silicon atom. The method of claim 11, wherein after performing step (b)
(c) quenching the reaction solution with water, heating and adding the non-solvent to form a precipitate; And
(d) washing the precipitate, drying and dispersing in a solvent, the method of preparing a polyurea porous-polyimide composite membrane. The method of claim 11,
The monomer having 2 to 4 isocyanate groups is a C1 to C20 aliphatic compound substituted with 2 to 4 isocyanate groups or a C6 to C30 aromatic compound substituted with 2 to 4 isocyanate groups, and the monomer having 2 to 4 amino groups. Is a C1 to C20 aliphatic compound substituted with 2 to 4 amino groups, or a C6 to C30 aromatic compound substituted with 2 to 4 amino groups, a polyurea porous-polyimide composite membrane manufacturing method. The method of claim 13,
The C1-C20 aliphatic compound substituted with the two isocyanate groups or the C1-C20 aliphatic compound substituted with the two amino groups is a compound represented by the following formula (3),
<Formula 3>

(Wherein R is all isocyanate groups or all amino groups, and n is an integer of 2 to 6)
At least any one selected from the group consisting of C6 to C30 aromatic compounds substituted with 2 to 4 isocyanate groups and C6 to C30 aromatic compounds substituted with 2 to 4 amino groups How to prepare one polyurea porous body:
<Formula 4>

<Formula 5>

<Formula 6>

<Formula 7>

(8)

&Lt; Formula 9 >

<Formula 10>

(Wherein R is all isocyanate groups or all amino groups) The method of claim 10, wherein preparing the polyamic acid solution
Mixing the diamine monomer and the dianhydride monomer on a solution; And
Method for producing a polyurea porous-polyimide composite membrane comprising the step of reacting the mixed solution at room temperature, nitrogen atmosphere. 16. The method of claim 15,
The diamine monomer is at least one selected from the following first compound group, and the dianhydride monomer is at least any one selected from the following second compound group polyurea porous-polyimide composite membrane manufacturing method:
<1st compound group>

,

,

,

<Second compound group>

,

,

,

,

,

,

The method of claim 10,
The concentration of the polyamic acid solution is 10 to 20 wt / vol% polyurea porous-polyimide composite membrane manufacturing method.

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