WO2018151438A1

WO2018151438A1 - Aerogel surface-modified with catechol-based compound, and preparation method therefor

Info

Publication number: WO2018151438A1
Application number: PCT/KR2018/001122
Authority: WO
Inventors: 박종남; 김현홍; 김현중; 김강용; 안병욱; 노동균
Original assignee: 에스케이씨 주식회사; 울산과학기술원
Priority date: 2017-02-15
Filing date: 2018-01-25
Publication date: 2018-08-23
Also published as: TW201831229A; KR101870958B1; TWI705852B

Abstract

Disclosed are aerogel surface-modified with a catechol-based compound, and a preparation method therefor, the aerogel having a large surface area, high porosity, and low thermal conductivity, and being economical and eco-friendly.

Description

[Specifications

Description of the Invention Aerogels Surface-Modified with Catechol-Based Compounds and Manufacturing Methods Thereof The embodiments are surface-modified with catechol-based compounds that are economical and environmentally friendly as well as having a large surface area, high porosity and low thermal conductivity. It relates to an airgel and a manufacturing method thereof. Background Art

Aerogel is a 3D reticulated nano skeleton structure, and due to its low dielectric constant, low thermal conductivity and high surface area, it is expected to be widely used as an anti-reflective coating film, flat panel display panel, and sensor. have.

Aerogels are prepared by removing the internal solvent from the wet gel synthesized through the sol-gel reaction of the precursor, wherein the solvent is removed under supercritical conditions and under atmospheric pressure. It is divided into methods. However, the method of removing the solvent under supercritical conditions has limited its use due to the high cost of the high temperature and high pressure process, and thus, a study on the method of removing the solvent under the atmospheric pressure has been conducted.

For example, Korean Patent Publication No. 2009-0053348 discloses trimethylchlorosilane.

Nano-functional silica using silylating agents such as trimethylchlorosilane (TMCS) A method of making an airgel thin film is disclosed. However, the method is dangerous because the reaction properties of the silylating agent is high, and toxic gas is generated when the reaction is carried out.

Therefore, there is a need for the development of aerogels using a new coating method that can maintain the skeleton of the nanostructure while improving the workability and physical properties simultaneously.

[Content of invention]

[Task to be solved]

When silylating agents such as trimethylchlorosilane (TMCS) are used in the preparation of the airgel, expensive silylating agents are not only used in excess, but also dangerous because of the occurrence of chlorine gas and subsequent corrosion during surface modification. There is a problem in that additional costs are incurred, and the incidence of vice versa is high.

Therefore, through the following embodiments, it is possible to provide an airgel and a method of manufacturing the surface-modified catechol-based compound, which can be synthesized under normal pressure, economical and environmentally friendly, wide surface area, high porosity, low thermal conductivity.

[Measures of problem]

According to one embodiment, an airgel surface modified with a catechol family compound is provided.

Further, according to one embodiment, preparing a wet gel using the sol-gel reaction of the nano-skeletal precursor; Mixing the wet gel with a polar solvent to replace the solvent in the wet gel with the polar solvent; Modifying the surface of the nanoskeleton by mixing the wet gel substituted with the polar solvent with a catechol-based compound; The surface modified Washing the wet gel with crab 1 organic solvent; Replacing the solvent in the washed wet gel with a system 2 organic solvent; And drying the wet gel substituted with the second organic solvent at 0 ^° C. to 20 ^° C., wherein the surface-modified airgel with the catechol-based compound is provided.

【Effects of the Invention】

The airgel surface-modified with the catechol-based compound according to the embodiment has an environmentally friendly, wide surface area, high porosity and low thermal conductivity, and can also lower the manufacturing cost by using a relatively inexpensive catechol-based compound.

Furthermore, according to the manufacturing method of the airgel, it is possible to synthesize the aerosol at atmospheric pressure conditions, not the conventional supercritical conditions, it is possible to manufacture the airgel safely and economically.

【Brief Description of Drawings】

1 is a SEM photograph of a silica airgel surface-modified with urushiol prepared in Example 1.

FIG. 2 is a SEM photograph of the surface-modified silica airgel with TBC prepared in Example 2. FIG.

FIG. 3 is an SEM photograph of silica airgel surface-modified with dopamine and TBC prepared in Example 3. FIG.

FIG. 4 is an SEM image of the surface-modified silica airgel with dopamine, TBC and hexylamine prepared in Example 4. FIG. Specific Contents for Carrying Out the Invention Hereinafter, an airgel and a method of manufacturing the same according to one embodiment will be described in detail. Airgel An airgel according to one embodiment is an airgel surface-modified with a catechol-based compound.

The surface of the modified airgel may be hydrophobic. The catechol-based compound may be a compound having a catechol group. That is, the catechol-based compound may include catechol and derivatives thereof.

The catechol group refers to a group in which a hydroxyl group (-OH) is substituted at an ortho position of the benzene ring. For example, the catechol group may be a 1,2-dihydroxybenzene group.

Specifically, the catechol-based compound is catechol, 4-tert-butylcatechol (4-tert-butylcatechol (TBC), urushiol (urushiol), dopamine (dopamine), alizarin (alizarin), tannic acid (tannic acid) ), Pyrogallol, gallic acid, epigallocatechin, epicatechin gallate, and epigallocatechin gallate. It may include, but is not limited thereto. By modifying the surface of the airgel with the catechol-based compound, the surface of the airgel becomes hydrophobic, thereby maintaining the structure of the nano-skeleton during atmospheric drying, thereby having high voids, low density, and low thermal conductivity. have. The airgel may include one or more selected from the group consisting of silica, titania and alumina. For example, the airgel may be a silica airgel, but is not limited thereto. The airgel surface-modified with the catechol-based compound is a porous material and has a reticulated skeletal structure. The surface area of the airgel is 300 to l, 500 m ² / g. Specifically, the surface area of the airgel may be 300 to 1,200 m ² / g, 300 to 1,000 m ² / g, or 300 to 600 m ² / g, but is not limited thereto. When the surface area of the airgel is in the above range, it is advantageous to exhibit high porosity, low density and low thermal conductivity. The volume of the voids formed in the airgel may be 0.01 to 100 cmVg. Specifically, the volume of the voids formed in the airgel may be 0.1 to 5 cm ³ / g, but is not limited thereto. When the volume of the voids formed in the airgel is in the above range, it is advantageous to exhibit high porosity, low density and low thermal conductivity. The average diameter of the pores formed in the airgel may be 12 to 100 nm. phrase In volume, the average diameter of the pores formed in the airgel may be 12 to 70 nm, 12 to 50 nm, or 15 to 100 nm, but is not limited thereto. When the average diameter of the pores formed in the aerogel is in the above range, it is advantageous to exhibit high porosity, low density and low thermal conductivity. The porosity of the airgel may be 60% or more. Specifically, the porosity of the airgel may be 70% or more, but is not limited thereto. When the porosity of the airgel is in the above range, it is advantageous to show the effect of low density and low thermal conductivity. Thermal conductivity of the airgel is 15 to 65 mW / m. It may be K. Specifically, the thermal conductivity of the airgel is 15 to 60 mW / m. It may be K. More specifically, the thermal conductivity of the airgel is 15 to 50 mW / m. It may be K, but is not limited thereto. When the thermal conductivity of the airgel is within the above range, it is advantageous to exhibit excellent heat insulating effect. In addition, the airgel may be surface modified with a catechol-based compound without using a silylating agent such as trimethylchlorosilane to maintain the skeleton of the nanostructure. That is, the airgel may have a nano coating layer of the catechol-based compound, wherein the average thickness of the nano coating layer may be 1 to 100 nm, or 1 to 50 nm. Method for preparing airgel A method for preparing an airgel surface-modified with a catechol-based compound according to an embodiment includes: preparing a wet gel using a sol-gel reaction of a nano-skeletal precursor; Mixing the wet gel with the polar solvent to replace the solvent in the wet gel with the polar solvent; Modifying the surface of the nanoskeleton by mixing the wet gel and the catechol-based compound substituted with the polar solvent; Washing the surface modified wet gel with a crab 1 organic solvent; Replacing the solvent in the washed wet gel with a second organic solvent; And drying the wet gel substituted with the second organic solvent at 0 ^° C. to 200 ^° C. First, the wet gel is prepared using the sol-gel reaction of the nano-skeletal precursor. At this time, the solution containing the nano-skeletal precursor may comprise the step of aging at 25 ^° C to 60 ^° C for 6 to 48 hours. This is a step of synthesizing the wet gel having a reticulated skeletal structure using the sol-gel reaction of the nano-skeletal precursor.

The sol-gel reaction is caused by hydrolysis, condensation, and coagulation of grown particles by a catalyst of a metal alkoxide precursor, and is a reaction to form a gel having a porous skeletal structure through aging.

The nano-skeletal precursor may include at least one selected from d-Cso metal alkoxides and silicate compounds.

For example, the nano-skeletal precursor is tetramethyl orthosilicate (TMOS), tetraethyl orthosilicate (tetraethyl orthosilicate; TEOS), titanium tetraisopropoxide (TTIP), titanium tetrabutoxide, aluminum tri-sec-butoxide and sodium silicate It may include one or more selected from the group, but is not limited thereto. Next, the wet gel and the polar solvent are mixed to replace the solvent in the wet gel with the polar solvent. This is a preliminary step for catechol surface treatment, to remove residual precursors and catalysts, and to substitute solvent conditions for surface treatment inside and outside the gel.

The polar solvent may be a polar protic solvent or a polar aprotic solvent.

Specifically, the polar protic solvent may include one or more selected from the group consisting of water, ethanol, methanol, and isopropanol, but is not limited thereto.

In addition, the polar aprotic solvent is acetone, propylene glycol monomethyl ether acetate (PGMEA), tetrahydrofuran (THF), ethyl acetate, chloroform, methylene chloride, dimethylformamide and dimethyl sulfoxide ( DMSO), but may include one or more selected from the group consisting of, but is not limited thereto.

Subsequently, the wet gel substituted with the polar solvent and the catechol-based compound are mixed to modify the surface of the nano backbone. This is because of the wet gel with the reticular skeletal structure. The surface is modified with a catechol series compound. At this time, the surface of the modified airgel becomes hydrophobic.

Specific types and properties of the catechol-based compound are as described above in the airgel.

The catechol-based compound may be added in an amount of 0.005 to 5 mmol / ml, more specifically, 0.01 to 2 mmol / ml.

When the content of the catechol-based compound is within the above range, the surface of the porous airgel may be hydrophobic and may be advantageous in increasing physical strength. When the catechol compound is added, an amine compound may be added together. Specifically, the amine-based compound may include one or more selected from the group consisting of primary amine-based compounds and diamine-based compounds, but is not limited thereto.

More specifically, the amine-based compound is nucleosilamine, octylamine (1- octylamine), dodecylamine (dodecylamine), nuxadecylamine (hexadecylamine), octadecylamine (Octadecylamine), oleylamine (Oleylamine), -tri Oxatridecanediamine (4,7,10-Trioxa-l, 13-tridecanediamine) and nucleomethylenediamine

It may include one or more selected from the group consisting of (hexamethylenediamine), but is not limited thereto.

When an amine compound is added to the catechol compound, it is advantageous to form a hydrophobic thin modified film and to increase the durability of the modified film through polymerization with the catechol compound. Next, the surface modified wet gel is washed with crab 1 organic solvent. This is the step of removing the counter reaction modifier and other organics.

The first organic solvent is ethanol, propylene glycol monomethyl ether acetate (PGMEA), tetrahydrofuran (THF), acetone, ethyl acetate, isopropanol, methane, chloroform, methylene chloride, dimethylform It may include one or more selected from the group consisting of amide and dimethyl sulfoxide (DMSO), but is not limited thereto. The solvent in the washed wet gel is then replaced with a second organic solvent. This is to minimize the shrinkage of the skeleton due to capillary pressure at atmospheric pressure by substituting the solvent in the wet gel with a second organic solvent having a low surface tension.

The second organic solvent may be an organic solvent having a low surface tension. Specifically, the surface tension of the second organic solvent may be 50 dyn / cm or less. More specifically, the surface tension of the second organic solvent may be 10 to 35 dyn / cm. More specifically, the surface tension of the second organic solvent may be 10 to 20 dyn / cm.

When the surface tension of the second organic solvent is in the above range, it is advantageous to minimize the shrinkage of the skeleton due to capillary pressure at atmospheric pressure.

For example, the second organic solvent may include one or more selected from the group consisting of nucleic acid, pentane, heptane, isopropanol, chloroform, methylene chloride, ether, acetone and tetrahydrofuran (THF), but It is not limited. Finally, the wet gel substituted with the second organic solvent is dried ^at 0 ^° C. to 200 ^° C.

The final aerogel can be obtained by removing the internal solvent from the wet gel through the drying. Removal of the solvent is possible at atmospheric pressure, not the supercritical conditions conventionally performed. The components, surface area, pore volume, average diameter, porosity and thermal conductivity of the final airgel obtained by the above method are as described in the above airgel. According to the manufacturing method of the surface-modified airgel, it is possible to synthesize under normal pressure conditions, and because it uses a relatively inexpensive catechol-based compound, the cost is reduced, and can be manufactured safely. In addition, the manufacturing method of the surface-modified airgel can be produced environmentally friendly airgel because it uses a catechol-based compound. In particular, the method for preparing the surface modified airgel is characterized in that it does not use a silylating agent such as trimethylchlorosilane (TMCS). If the silylating agent is used in the method for preparing the surface-modified airgel, since the reaction property of the silylating agent is high and dangerous and toxic gas such as chlorine gas is generated when reacting, the additional cost is required in designing the reaction product. May occur. However, the manufacturing method of the surface-modified airgel according to the embodiment may have the advantage that it is eco-friendly and economical, and no side reaction occurs. EXAMPLES Hereinafter, although an Example demonstrates further in detail, it is not limited to these ranges. Example 1 Preparation of Surface Modified Silica Aerogels with Urushiol

4.7 g of tetraethylorthosilicate (TEOS), 10 ml of ethane, 1.3 ml of water and 36% hydrochloric acid 2.8! After mixing and undergoing hydrolysis for 10 minutes, a wet gel was prepared by adding 30% ammonium hydroxide aqueous solution. The prepared wet gel was aged at 50 ^° C. for 48 hours, crushed, and washed with a small amount of ethanol. The wet gel and propylene glycol monomethyl ether acetate (PGMEA) were combined to replace the solvent in the wet gel with PGMEA. The wet gel substituted with PGMEA was placed in 20 ml of a mixed solution of urushiol and PGMEA, and the surface of the nanoskeleton was modified for 24 hours. The surface modified wet gel was washed with PGMEA and heat treated at 10 CTC for 12 hours. The solvent in the wet gel was substituted with nucleic acid and dried at 60 ^° C. to obtain a surface modified silica airgel. Example 2 Preparation of Surface-Modified Silica Aerogels with TBC

4.7 g of TEOS, 10 ml of ethanol, 1.3 ml of water, and 2.8 ^ of 36% hydrochloric acid were mixed, hydrolyzed for 10 minutes, and then a 30% aqueous ammonium hydroxide solution was added to prepare a wet gel. The prepared wet gel was aged at 50 ^° C. for 48 hours, crushed and washed with a small amount of ethanol. The wet gel and PGMEA by mixing The solvent in the wet gel was replaced with PGMEA. The wet gel substituted with PGMEA was added to 20 ml of a mixed solution of 4-tert-butylcatechol (TBC) and PGMEA at pH 8, and the surface of the nanoskeleton was modified for 24 hours. The surface modified wet gel was washed with PGMEA and the solvent in the washed wet gel was replaced with nucleic acid. After drying at 60 ^° C to obtain a surface-modified silica airgel. Example 3 Preparation of Surface-Modified Silica Aerogels with Dopamine and TBC

A wet gel was prepared by mixing 6.6 ml of a silica silicate solution with a silica content of 5 weight «¾ and 3.3 ^ 1.15 M hydrochloric acid as an acid catalyst, and then aging at 50 ^° C. for 48 hours. After breaking up the wet gel, the solvent in the wet gel was replaced with water by mixing with water. The wet gel substituted with water was added 40 ml of ethane in which 4 mg of dopamine and 3.5 mg of TBC were dissolved, followed by surface modification for 12 hours. The surface modified wet gel was washed with ethane and the solvent in the wet gel was substituted with isopropanol and nucleic acid. After drying at 60 ^° C to obtain a surface-modified silica airgel. Example 4 Preparation of Silica Aerogel Surface Modified with Dopamine, TBC, and Nucleylamine

A wet gel was prepared by mixing 6.6 ml of a sodium silicate solution with a silica content of 5% by weight and 3.3 ^ of 1.15 M hydrochloric acid as an acid catalyst, and then aging at 50 ^° C. for 48 hours. After breaking up the wet gel, the solvent in the wet gel was replaced with water by mixing with water. The wet gel substituted with water, ethanol dissolved in 1.3 mg of dopamine and 5.8 mg of TBC were added to a mixed solution of 40 ml and 0.11 ml of nucleosilamine, followed by surface modification for 12 hours. Proceeded. The surface modified wet gel was washed with ethane and the solvent in the wet gel was substituted with isopropanol and nucleic acid. After drying at 60 ^° C to obtain a surface-modified silica airgel. Comparative Example 1 Preparation of Silica Aerogels Surface-Modified with Catechol-Based Compounds After mixing 6.6 ml of sodium silicate solution with a silica content of 5% by weight with 3.3 rank of 1.15 M hydrochloric acid as an acid catalyst, the mixture was aged at 50 ^° C. for 48 hours. Wet gels were prepared. After breaking up the wet gel, the solvent in the wet gel was replaced with water by mixing with water. The surface modified wet gel was washed with ethanol and the solvent in the wet gel was substituted using isopropanol and nucleic acid. Then dried at 6CTC to obtain the final airgel. Evaluation Example 1 Surface Area of Airgel

The surface area of the airgel prepared in Examples 1 to 4 and Comparative Example 1 was measured by the BET (Brunauer, Emmett and Teller) method. The results are shown in Table 1 below. Evaluation example 2: volume of voids formed in the airgel

The volume of the pores formed in the airgel prepared in Examples 1 to 4 and Comparative Example 1 was measured by the BET method. The results are shown in Table 1 below. Evaluation example 3: average diameter of the space | gap formed in an airgel The average diameter of the pores formed in the airgel prepared in Examples 1 to 4 and Comparative Example 1 was measured by the BET method. The results are shown in Table 1 below. Evaluation Example 4: Thermal Conductivity of Airgel

The thermal conductivity of the airgel prepared in Example 4 and Comparative Example 1 was measured by an instrument (C—Therm Thermal Conductivity Analyzer) based on the Modified Transient Plane Source (MTPS) method. The results are shown in Table 1 below.

Table 1

As shown in Table 1, Examples 1 to 4 has a larger surface area than Comparative Example 1, a large volume of the pores and a long average diameter of the pores have a high porosity, it was confirmed that the thermal conductivity is also excellent.

In addition, the surface-modified airgel in which the pores exist can be confirmed through FIGS. 1 to 4 showing SEM images of Examples 1 to 4. FIG.

Claims

[Claim]

[Claim 1]

Aerogels surface modified with catechol family compounds.

[Claim 2]

In U,

_O Airgel, wherein the surface of the modified airgel is hydrophobic.

[Claim 3]

The method of claim 1,

An airgel, wherein the catechol-based compound is a compound having a catechol group.

[Claim 4]

The method of claim 1,

The catechol-based compound is catechol, 4-tert-butylcatechol (4-tert-butylcatechol (TBC), urushiol (urushiol), dopamine (dopamine), alizarin (alizarin), tannic acid (tannic acid), pyro Aerogels comprising at least one member selected from the group consisting of galrogalol, gallic acid, epigallocatechin, epicatechin gallate and epigallocatechin gallate .

[Claim 5]

The method of claim 1,

The airgel comprises one or more selected from the group consisting of silica, titania and alumina.

[Claim 6]

The method of claim 1,

An airgel having a surface area of 300 to 1500 m ² / g.

[Claim 7]

The method of claim 1,

The average diameter of the pores formed in the airgel is 12 to 100 nm, an airgel.

[Claim 8]

Preparing a wet gel using a sol-gel reaction of the nano-skeletal precursor;

Mixing the wet gel with the polar solvent to replace the solvent in the wet gel with the polar solvent;

Mixing the wet gel substituted with the polar solvent with a catechol-based compound to modify a surface of a nano skeleton;

Washing the surface modified wet gel with a first organic solvent;

Replacing the solvent in the washed wet gel with a second organic solvent; And And drying the wet gel substituted with the second organic solvent at 0 ^° C. to 200 ^° C., wherein the surface-modified airgel with the catechol-based compound is prepared.

[Claim 9]

The method of claim 8,

The nano-skeletal precursor comprises at least one selected from d-Czo metal alkoxide and silicate-based compound, a method for producing an airgel.

[Claim 10]

The method of claim 8,

The nano-skeletal precursors are tetramethyl orthosilicate (TMOS), tetraethyl orthosilicate (TEOS), titanium tetraisopropoxide (TTIP), titanium tetrabutoxide (titanium tetrabutoxide) A process for producing an airgel, comprising at least one member selected from the group consisting of aluminum tri-sec-butoxide and sodium silicate.

[Claim 11]

The method of claim 8,

The polar solvent is a polar protic solvent or a polar aprotic solvent, the polar protic solvent comprises at least one selected from the group consisting of water, ethanol, methanol and isopropanol, The polar aprotic solvents include acetone, propylene glycol monomethyl ether acetate (PGMEA), tetrahydrofuran (THF), ethyl acetate, chloroform, methylene chloride, dimethylformamide and dimethylsulfoxide (DMSO A method for producing an aerogel, comprising one or more selected from the group consisting of.

[Claim 12]

The method of claim 8,

The catechol-based compound is a compound having a catechol group, a method for producing an airgel.

[Claim 13]

The method of claim 8,

The catechol-based compound is catechol, 4-tert-butylcatechol (4-tert-butylcatechol (TBC), urushiol (urushiol), dopamine (dopamine), alizarin (alizarin), tannic acid (tannic acid), pyro Aerogels comprising at least one member selected from the group consisting of galrogalol, gallic acid, epigallocatechin, epicatechin gallate and epigallocatechin gallate Manufacturing method.

[Claim 14]

According to claim 18,

The Crab 1 organic solvent is ethanol, propylene glycol monomethyl ether acetate. (propylene glycol monomethyl ether acetate; PGMEA), tetrahydrofuran (THF), acetone, ethyl acetate, isopropanol, methanol, chloroform, methylene chloride, dimethylformamide and dimethyl sulfoxide (DMSO) Comprising, airgel production method.

[Claim 15]

The method of claim 8,

The manufacturing method of an airgel whose surface tension of the said 2nd organic solvent is 50 dyn / cm or less.

[Claim 16]

According to clause 115,

And the second organic solvent comprises at least one selected from the group consisting of nucleic acid, pentane, heptane, isopropanol, chloroform, methylene chloride, ether, acetone and tetrahydrofuran (THF).

[Claim 17]

According to claim 18,

The surface area of the airgel is 300 to 1,500 m ² / g, airgel manufacturing method.

[Claim 18]

The method of claim 8, The average diameter of the pores formed in the airgel is 12 to 100 nm, a method for producing an airgel.