KR102136283B1 - Nanoporous microspherical polyimide aerogel and method for manufacturing the same - Google Patents

Abstract

The present invention relates to a nano-porous micro spherical polyimide aerogel and a method for manufacturing the same.
If the polyimide airgel manufacturing method according to an embodiment of the present invention is used, it can be manufactured in a low temperature process, thereby saving time and energy, reducing manufacturing cost, and reducing the size of nanopores It is possible to manufacture a spherical polyimide airgel, which is a uniform particle of micro size, having excellent chemical stability, heat insulation, and adsorption and desorption properties. The spherical polyimide airgel can be applied to various fields such as an insulating material, a drug delivery medium, and a catalyst carrier due to excellent physical properties.

Description

Nanoporous microspherical polyimide aerogel and method for manufacturing the same}

The present invention relates to a nanoporous micro-spherical polyimide airgel and a method for manufacturing the same, and more specifically, to prepare a polyamic acid precursor composition in an airgel form, has excellent chemical stability, heat insulation and adsorption and desorption properties, and provides nano-sized pores. The present invention relates to a spherical polyimide airgel having uniform particles of micro size and a method for manufacturing the same.

Aerogels were discovered in the 1930s and have been studied in a variety of ways. Among them, silica aerogels, the most common type, have excellent physical properties, such as medical equipment, drug delivery media, and catalysts for aerospace and building insulation, body organ storage and transportation, etc. It is an ultra-light new material that has a wide range of applications in energy, environment, electrical and electronic, space, and medical fields, such as carriers and electrical insulating films with low dielectric constant.

However, in order to manufacture a silica airgel having excellent physical properties, the micropores should not be destroyed. To prevent this, the silica airgel uses a drying method using supercritical carbon dioxide. However, such a supercritical drying method requires high pressure and high temperature, so there is a risk of safety accidents, and there are disadvantages of continuous process difficulty and high manufacturing cost due to the size limitation of the autoclave container.

In order to solve this problem, research into manufacturing an airgel using various raw materials has been conducted (Patent Document 1, Patent Document 2), and research into manufacturing an airgel using a polymer has been variously attempted.(Patent Document 3)

Polyimide resin is a state-of-the-art chemical material that is in the spotlight in areas requiring high heat resistance, low insulation, and high strength.It has a chemical structure that does not decompose even at high temperatures of 400℃ or higher, and is thin and excellent in flexibility. It is widely used as a key material in industries such as IT, automobile, semiconductor, and display. NASA has developed an airgel sheet using polyimide, but the production method is limited to polyimide types, and by using a supercritical carbon dioxide drying method, the production cost is high, and the airgel is a drug delivery medium and a catalyst carrier. In order to use it as an insulating material, it is advantageous to develop a polyimide airgel in a new form in that it is advantageous to manufacture in a particle form rather than a sheet form.

Therefore, if a polyimide aerogel of spherical shape, which is a micro-sized uniform particle, has nano-sized pores that can replace silica aerogels using a low-temperature process using a polyimide material having excellent physical properties, silica aerogels and sheet form It is expected to solve the shortcomings of polyimide aerogels.

Korean Patent Publication No. 10-2012-0103646 Korean Patent Publication No. 10-2010-0098905 U.S. Patent No. 7,074,880

An object of the present invention is to provide a nano-porous micro-spherical polyimide aerogel, which is a micro-sized uniform particle having excellent pore size and excellent chemical stability, heat insulation and adsorption and desorption properties, and a method for manufacturing the same.

The present invention to solve the above problems,

It provides a nano-porous micro-spherical polyimide airgel comprising a polyimide polymer having a repeating unit represented by any one of the following Formulas 1 to 3.

[Formula 1]

[Formula 2]

[Formula 3]

In Chemical Formulas 1 to 3,

Ar, Ar _{1 and} Ar ₂ are at least one aromatic selected from the following structural formulas 1 to 6, and Ar', Ar' ₁ and Ar' ₂ are at least one aromatic selected from the following structural formulas 7 to 12.

n is an integer that satisfies 50≤n≤10000, m is an integer that satisfies 25≤m≤10000, and l is an integer that satisfies 25≤l≤10000.

The molar ratio m:l between each repeating unit in the polyimide polymer having the repeating unit represented by Chemical Formula 2 or 3 may be 0.5:9.5 to 9.5:0.5.

The present invention to solve the above problems,

In the method for producing a nano-porous micro-spherical polyimide airgel comprising a polyimide polymer having a repeating unit represented by any one of the formulas 1 to 3,

(a) synthesizing a polyamic acid precursor by reacting an aromatic dianhydride and an aromatic diamine in an organic polar solvent;

(b) putting the polyamic acid precursor into a heat-resistant container of an autoclave and sealing it by putting a nonsolvent between the autoclave and the heat-resistant container;

It provides a method for producing a nano-porous micro-spherical polyimide airgel comprising; (c) step of curing after drying at 200 to 350° C. after sealing.

The concentration of the solid content of the polyamic acid precursor synthesized in step (a) may be 5 to 50% by weight compared to the total solution.

In the step (a), the organic polar solvent may be any one selected from N-methylpyrrolidone (NMP), N,N-dimethylacetamide (DMAc) and dimethylformamide (DMF).

In the step (a), the aromatic dianhydride is 4,4'-(hexafluoroisopropylidene)diphthalic dianhydride (6FDA), pyromellitic dianhydride (PMDA), 3,3'4,4'- Benzophenonetetracarboxylic dianhydride (BTDA), 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA), 4,4'-oxydiphthalic dianhydride (ODPA) and 3, It may be any one selected from 3',4,4'-diphenylsulfonetetracarboxylic dianhydride (DSDA).

In step (a), the aromatic diamine is 2,2'-bis(3-amino-4-hydroxyphenyl)-hexafluoropropane (AHHFP), 4,4'-oxydianiline (4,4'- ODA), 3,4'-oxydianiline (3,4'-ODA), 1,4-phenylene diamine (1,4-PDA), 4,4'-sulfonyldianiline (4,4'- DDS) and diaminophenylmethane (MDA).

In step (b), the nonsolvent may be acetone or ethyl acetate.

Other specific details of the embodiments of the present invention are included in the following detailed description.

By using the method of manufacturing a nano-porous micro-spherical polyimide aerogel according to an embodiment of the present invention, it can be manufactured by a low-temperature process, saving time and energy compared to a conventional manufacturing method, and reducing manufacturing cost. In addition, it is possible to manufacture a spherical polyimide aerogel, which is a uniform particle of micro size, which has nano-size pores and has excellent chemical stability, heat insulation, and adsorption and desorption properties. The nano-porous micro-spherical polyimide airgel can be applied to various fields such as an insulating material, a drug delivery medium, and a catalyst carrier due to its excellent physical properties.

1 is a graph showing the results of thermogravimetric analysis of a nanoporous micro spherical polyimide airgel using a polyamic acid precursor according to an embodiment of the present invention.
Figure 2 shows the particle size sidtribution of the nano-porous micro-spherical polyimide airgel according to an embodiment of the present invention.
3 is a photograph of a nanoporous micro spherical polyimide aerogel according to an embodiment of the present invention taken using SEM.
Figure 4 is a photograph of the nano-pores of the nano-sized Pore on the surface of the nano-porous micro-spherical polyimide aerogel according to an embodiment of the present invention using SEM.
Figure 5 is a data measuring the specific surface area and porosity of the nano-porous micro-spherical polyimide airgel according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art to which the present invention pertains can easily practice. However, the present invention may be implemented in various different forms and is not limited to the embodiments described herein.

The polyimide airgel according to an embodiment of the present invention includes a polymer having nano-sized micropores, and is a micrometer-sized spherical particle.

In the polyamic acid precursor according to an embodiment of the present invention, as shown in the following Reaction Scheme 1, the rings at both ends of the dianhydride react with the amine groups of the diamine to form a polyamic acid precursor in a solution state. The imidization reaction through 2 proceeds to form a polyimide polymer through a dehydration condensation reaction.

<Scheme 1>

<Reaction Scheme 2>

The nano-porous micro-spherical polyimide aerogel according to the present invention is prepared by using a polyamic acid precursor and may include a polyimide polymer having a repeating unit represented by any one of the following Chemical Formulas 1 to 3.

[Formula 1]

[Formula 2]

[Formula 3]

In Chemical Formulas 1 to 3,

Specific examples of Ar, Ar _{1 and} Ar ₂ may be selected from the following structural formulas 1 to 6, but are not limited thereto.

Specific examples of Ar', Ar' ₁ , and Ar' ₂ may be selected from the following structural formulas 7 to 12, but are not limited thereto.

n is an integer that satisfies 50≤n≤10000, m is an integer that satisfies 25≤m≤10000, and l is an integer that satisfies 25≤l≤10000.

Method for producing a nano-porous micro-spherical polyimide airgel comprising a polyimide polymer having a repeating unit represented by any one of Chemical Formulas 1 to 3 according to the present invention,

(a) synthesizing a polyamic acid precursor by reacting an aromatic dianhydride and an aromatic diamine in an organic polar solvent;

(b) putting the polyamic acid precursor into a heat-resistant container of an autoclave and sealing it by putting a nonsolvent between the autoclave and the heat-resistant container;

(c) after the sealing, the drying may be performed after curing at 200 to 350° C. step by step.

The molar ratio m:l between each repeating unit in the polyimide polymer comprising the repeating units represented by Chemical Formulas 2 to 3 is preferably 0.5:9.5 to 9.5:0.5.

The concentration of the solid content of the polyamic acid precursor is preferably 5 to 50% by weight relative to the total solution.

The organic polar solvent is preferably one selected from N-methylpyrrolidone (NMP), N,N-dimethylacetamide (DMAc) and dimethylformamide (DMF), but is not limited thereto.

The aromatic dianhydride is 4,4'-(hexafluoroisopropylidene)diphthalic dianhydride (6FDA), pyromellitic dianhydride (PMDA), 3,3',4,4'-benzophenonetetracar Acidic dianhydride (BTDA), 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA), 4,4'-oxydiphthalic dianhydride (ODPA) and 3,3',4 ,4'-diphenylsulfonetetracarboxylic dianhydride (DSDA) is preferably any one selected, but is not limited thereto.

The aromatic diamine is 2,2'-bis(3-amino-4-hydroxyphenyl)-hexafluoropropane (AHHFP), 4,4'-oxydianiline (4,4'-ODA), 3, 4'-oxydianiline (3,4'-OD A), 1,4-phenylene diamine (1,4-PDA), 4,4'-sulfonyldianiline (4,4'-DDS) and die It is preferable to be any one selected from aminophenylmethane (MDA), but is not limited thereto.

The nonsolvent can be any liquid liquid having a low vaporization temperature, but is more preferably acetone or ethyl acetate.

The polyimide aerogel is preferably prepared by adding a polyamic acid precursor and a nonsolvent to an autoclave, sealing it, and gradually curing it at 200 to 350°C, followed by drying. 45 to 75 minutes at 70 to 90 °C, 20 to 40 minutes at 130 to 170 °C, 20 to 40 minutes at 180 to 220 °C, 20 to 40 minutes at 230 to 250 °C, 100 to 140 minutes at 320 to 380 °C It is preferred to dry after stepwise curing.

The size of the polyimide airgel according to an embodiment of the present invention may be 3.5 to 5.5 μm, but is not limited thereto.

The specific surface area of the polyimide airgel may be 90 to 120 m 2 /mm 2, and the porosity may be 80 to 90%, but is not limited thereto.

Hereinafter, specific examples, manufacturing examples, test examples, and evaluation examples according to the present invention will be described in detail. However, the present invention may be implemented in various different forms and is not limited to the embodiments described herein.

Manufacturing example : Polyamic acid Preparation of precursors

Scheme 3 below shows a schematic process for synthesizing a polyamic acid precursor as a preferred embodiment of the present invention. 0.801 g (3 mmol) of 4,4'-oxydianiline (4,4'-oxydianiline) was added to a 50 ml Erlenmeyer flask, and 10 ml of a polar solvent, NMP, was added together to stir until dissolved. Then, pyromellitic dianhydride (Pyromellitic dianhydride) was added in the same mole number 0.873g (3mmol) and stirred for 24 hours under a nitrogen atmosphere at 0 ℃.

<Scheme 3>

Example : Manufacturing nanoporous micro spherical polyimide airgel

Reaction Scheme 4 below shows a schematic process for preparing a nanoporous micro spherical polyimide airgel using a polyamic acid precursor as a preferred embodiment of the present invention. The polyamic acid composition synthesized through the above preparation example is placed in a heat-resistant container of an autoclave, acetone is placed between the autoclave and the heat-resistant container, and then in an oven at 80°C for 1 hour, at 150°C for 30 minutes, and at 200°C for 30 minutes. , Polyimide polymer was synthesized in airgel form by curing stepwise at 250°C for 30 minutes and at 350°C for 2 hours. Thereafter, to collect the airgel, it was dried in a vacuum oven at 80° C. for 24 hours to finally obtain a micro-sized spherical polyimide airgel having nano-sized pores.

<Reaction Scheme 4>

Test example . Thermogravimetric analysis( Thermogravimetric analysis )

In order to confirm the thermal stability of the highly functional nanoporous micro spherical polyimide aerogel using the polyamic acid precursor of the present invention, thermogravimetric analysis was performed to measure mass change by applying heat from room temperature to 800°C.

1 is a graph showing the results of thermogravimetric analysis of a nanoporous micro spherical polyimide airgel using a polyamic acid precursor according to an embodiment of the present invention. Through these results, it was confirmed that the thermal properties of the nanoporous micro-spherical polyimide aerogel of the present invention show significantly higher thermal stability even at high temperatures. When the 1% weight loss temperature is 520°C and the 5% weight loss temperature is 580°C, it can be seen that the nanoporous micro spherical polyimide airgel of the present invention has excellent thermal stability.

Test example . dynamic Light scattering Photometer ( dynamic light scattering )

The particle size of the nanoporous micro-spherical polyimide aerogel using the polyamic acid precursor of the present invention was measured to analyze the fluidity between polymer polymer chains, and analysis was performed using a dynamic light scattering photometer.

Figure 2 shows the particle size sidtribution of the nano-porous micro-spherical polyimide airgel according to an embodiment of the present invention. Through these results, the size of the nano-porous micro-spherical polyimide aerogel of the present invention can be confirmed to have particles of uniform shape ranging from 3.5 to 5.5 micro μm, and it can be inferred that it is fairly uniform.

Evaluation example

3 is a photograph of a nanoporous micro spherical polyimide aerogel according to an embodiment of the present invention taken using SEM. Through this, it can be confirmed that the nano-porous micro-spherical polyimide aerogel of the present invention has a micro-micron size and spherical uniform particles.

FIG. 4 is a photograph of a nano-sized Pore on the surface of a nano-porous micro-spherical polyimide aerogel according to an embodiment of the present invention. Figure 5 is a data measuring the specific surface area and porosity of the nano-porous micro-spherical polyimide airgel according to an embodiment of the present invention. Through this, it can be seen that the nanoporous micro-spherical polyimide airgel of the present invention has high porosity of 80 to 90% and a large specific surface area of 90 to 120 m 2 /mm 2, thereby providing excellent physical properties.

Claims (9)

delete delete In the manufacturing method of the nano-porous micro spherical polyimide airgel,
(a) reacting an aromatic dihydride with an aromatic diamine in an organic polar solvent to synthesize a polyamic acid precursor;
(b) putting the polyamic acid precursor into a heat-resistant container of an autoclave and sealing it by putting a nonsolvent between the autoclave and the heat-resistant container;
(c) the step of curing after drying at 200 to 350° C. after the sealing, and drying.
The polyimide airgel has a size of 3.5 to 5.5 μm, and a specific surface area of 90 to 120 m 2 /mm 2. delete According to claim 3,
The method of manufacturing a nanoporous micro spherical polyimide airgel, characterized in that the concentration of solid content of the polyamic acid precursor synthesized in step (a) is 5 to 50% by weight compared to the total solution. According to claim 3,
Nanoporous microspheres characterized in that the organic polar solvent of step (a) is any one selected from N-methylpyrrolidone (NMP), N,N-dimethylacetamide (DMAc) and dimethylformamide (DMF). Polyimide airgel manufacturing method. According to claim 3,
The aromatic dianhydride of step (a) is 4,4'-(hexafluoroisopropylidene)diphthalic dianhydride (6FDA), pyromellitic dianhydride (PMDA), 3,3'4,4'- Benzophenonetetracarboxylic dianhydride (BTDA), 3,3',4,4'-biphenyltetracarboxylic dianhydride (BPDA), 4,4'-oxydiphthalic dianhydride (ODPA) and 3, 3',4,4'-diphenylsulfonetetracarboxylic dianhydride (DSDA) method of manufacturing a nano-porous micro spherical polyimide airgel, characterized in that any one selected from. According to claim 3,
The aromatic diamine of step (a) is 2,2'-bis(3-amino-4-hydroxyphenyl)-hexafluoropropane (AHHFP), 4,4'-oxydianiline (4,4'-) ODA), 3,4'-oxydianiline (3,4'-ODA), 1,4-phenylene diamine (1,4-PDA), 4,4'-sulfonyldianiline (4,4'- DDS) and diaminophenylmethane (MDA) method of manufacturing a nano-porous micro-spherical polyimide airgel, characterized in that any one. According to claim 3,
The method of manufacturing a nanoporous micro spherical polyimide airgel, wherein the nonsolvent in step (b) is acetone or ethyl acetate.

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