Graphene quantum dots and method for manufacturing the same

Abstract

Provided are graphene quantum dots having mite-proof, mold-proof, deodorizing functions, excellent antibacterial properties, and antistatic, heat storage and heat insulation, and heat re-radiation characteristics, which promote blood microcirculation, and a method for producing the same. 【Solution means】 A method for producing graphene quantum dots with a particle size of 10 nm or less includes a first aqueous dispersion preparation step of reacting graphene oxide, hydrogen peroxide, and aqueous ammonia to prepare a first graphene quantum dot aqueous dispersion, a second aqueous dispersion preparation step in which a reducing agent and a phosphate are added to the first graphene quantum dot aqueous dispersion, microwave irradiation is performed in the range of 100 to 200 °C, and a second graphene quantum dot aqueous dispersion in which graphene quantum dots with a particle size of 10 nm or less are dispersed is prepared, and a freeze-drying step in which the second graphene quantum dot aqueous dispersion is freeze-dried to obtain graphene quantum dots with a particle size of 10 nm or less.

Description

Technical Field

[0001] The present invention relates to graphene quantum dots and a method for manufacturing the same.

Background Art

[0002] Graphene has excellent performance and is applied in various fields. In recent years, research on the use of graphene in composite materials and spinning has also advanced. For example, Patent Document 1 discloses a graphene-nano silver composite material. Patent Document 2 discloses a method for preparing a polymer-based silver-containing graphene nano antibacterial material. Patent Document 3 discloses a graphene quantum dot-modified polymer masterbatch for functional fibers and a method for manufacturing the same.

[0003] However, in the materials disclosed in Patent Documents 1 and 2, the particle size of graphene is large, the antibacterial ability is low, and since a metal silver material is used, it places a burden on the environment and is also harmful to health. The functional masterbatch obtained according to the manufacturing method disclosed in Patent Document 3, when used in spinning, is not uniformly dispersed when mixed with each raw material, cannot fully exhibit the nano knife effect of graphene quantum dots, and has low antibacterial properties. In addition, due to the aggregation of graphene, excessive pressure is applied to the spinning assembly, graphene is not uniformly dispersed in the fiber matrix, and the heat re-radiation blocking effect of graphene is reduced. Furthermore, the conductive mesh of graphene in the fiber matrix is not formed, resulting in a decrease in antistatic performance. and In recent years, graphene quantum dots having new functions and resin compositions containing the graphene quantum dots have been in demand.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0005] The problem to be solved by the present invention is to provide graphene quantum dots, a resin composition, a masterbatch, a fiber, and a manufacturing method thereof, which have anti-mite, anti-mold, deodorizing functions, excellent antibacterial properties, and antistatic, heat storage and heat preservation, and heat re-radiation characteristics, and promote blood microcirculation, and contain two components of graphene quantum dots and graphene.

Means for Solving the Problems

[0006] In view of the above problems, the present inventors have conducted repeated studies and found that graphene quantum dots with flavonoids chemically bonded to the surface or graphene quantum dots with a particle size of 10 nm or less have additional new functions in addition to antibacterial properties. The present invention has been completed based on these findings. In order to achieve the above object, the present invention provides the following means.

[0007] On the surface is mugwort extract Graphene quantum dots to which flavonoids are chemically bonded. The particle size of the graphene quantum dots is preferably 10 nm or less.

[0008] The present invention is a method for producing graphene quantum dots with a particle size of 10 nm or less, comprising: A first aqueous dispersion preparation step of reacting graphene oxide, hydrogen peroxide, and aqueous ammonia to prepare a first graphene quantum dot aqueous dispersion; A second aqueous dispersion preparation step of adding a reducing agent and a phosphate to the first graphene quantum dot aqueous dispersion, irradiating with microwaves in the range of 100 to 200 °C, and preparing a second graphene quantum dot aqueous dispersion in which graphene quantum dots with a particle size of 10 nm or less are dispersed; and The present invention relates to a method for producing graphene quantum dots with a particle size of 10 nm or less, including a freeze-drying step in which the second graphene quantum dot aqueous dispersion is freeze-dried to obtain graphene quantum dots with a particle size of 10 nm or less.

[0009] The method for producing graphene quantum dots with a particle size of 10 nm or less according to the present invention preferably further includes a flavonoid reaction step of reacting the second graphene quantum dot aqueous dispersion with a flavonoid.

Advantages of the Invention

[0010] The graphene quantum dots with a particle size of 10 nm or less according to the present invention have excellent antibacterial properties with acarid-proof, mildew-proof, and deodorizing functions, and also have antistatic, heat storage and heat preservation, and heat re-radiation properties, and can promote blood microcirculation. Since they do not use silver, they can prevent contamination of the human body by heavy metals and are environmentally friendly.

[0011] The method for producing graphene quantum dots according to the present invention can produce graphene quantum dots with a particle size of 10 nm or less having a uniform particle size. The graphene quantum dots with a particle size of 10 nm or less produced by the production method of the present invention can be efficiently dispersed in the molecular gap between polymers during the polymerization process of the polymer material, improve the physical strength of the polymer material itself, improve internal defects, and improve the performance of polymer products.

Brief Description of the Drawings

[0012]

Figure 1

Embodiments for Carrying Out the Invention

[0013] The present invention will be described in more detail. Note that, unless otherwise specified, "~" in a numerical range represents "from... to...", including both of the numerical values at both ends. Also, when a numerical range is indicated, the upper limit value and the lower limit value can be appropriately combined, and the resulting numerical range is also considered to be disclosed.

[0014] <Graphene quantum dot> The graphene quantum dot of the present invention is a graphene quantum dot with a particle size of 10 nm or less. This graphene quantum dot has excellent bactericidal and deodorizing performance. When it comes into contact with bacteria, pressure is applied to the cell membrane, and an oxidation reaction occurs between the functional group of the graphene quantum dot and the cell membrane, breaking through the cell wall, causing the RNA or DNA inside the bacterial cell to flow out, and being inactivated. Also, the specific surface area of the graphene quantum dot of the present invention with a particle size of 10 nm or less is extremely large, reaching 500~1000 m 2 / g, its adsorption capacity is particularly strong, it has an excellent adsorption and removal effect on odors, is excellent in biocompatibility, toxicity, and safety, and is also environmentally friendly.

[0015] In the graphene quantum dot of the present invention, flavonoid is chemically bonded to the surface. By grafting flavonoid onto the graphene quantum dot, the graphene quantum dot can be modified, which helps in killing mites and can impart the effect of repelling mites. As the raw material of flavonoid, it is preferable to use mugwort extract.

[0016] Preferably, the graphene quantum dot of the present invention has flavonoid chemically bonded to the surface and a particle size of 10 nm or less. By grafting flavonoid onto the surface of the graphene quantum dot, a mite repellent effect is imparted. And since the particle size is 10 nm and the specific surface area is extremely large, the deodorizing and antibacterial effects can be improved. Furthermore, the graphene quantum dot with a particle size of 10 nm or less forms a prism-like diffuse reflection effect on ultraviolet light in the long wavelength region, effectively dissipating the ultraviolet light and reducing the damage to the skin.

[0017] The graphene quantum dots with a particle size of 10 nm or less are preferably flavonoid-modified graphene quantum dots in which flavonoids are chemically bonded to the surface.

[0018] <Method for producing graphene quantum dots> The method for producing graphene quantum dots with a particle size of 10 nm or less according to the present invention comprises: a first aqueous dispersion preparation step of reacting graphene oxide, hydrogen peroxide, and aqueous ammonia to prepare a first aqueous dispersion of graphene quantum dots; a second aqueous dispersion preparation step of adding a reducing agent and a phosphate to the first aqueous dispersion of graphene quantum dots, irradiating with microwaves in the range of 100 to 200 °C, and preparing a second aqueous dispersion of graphene quantum dots in which graphene quantum dots with a particle size of 10 nm or less are dispersed; and a lyophilization step of lyophilizing the second aqueous dispersion of graphene quantum dots to obtain graphene quantum dots with a particle size of 10 nm or less.

[0019] The method for producing graphene quantum dots with a particle size of 10 nm or less according to the present invention preferably further includes a flavonoid reaction step of mixing the second aqueous dispersion of graphene quantum dots and a flavonoid, performing ultrasonic treatment at 185 to 200 °C for 2 to 5 hours, and reacting the graphene quantum dots with the flavonoid.

[0020] Examples of the flavonoid include flavonoid-containing substances such as mugwort extract. In the flavonoid reaction step, the mass ratio of the second aqueous dispersion of graphene quantum dots to the mugwort extract is preferably in the range of 50 to 70:50 to 30.

[0021] The graphene quantum dots produced by the production method of the present invention have a particle size of 10 nm or less and a uniform particle size, and have a very large specific surface area, so that the deodorizing and antibacterial effects can be improved. In addition, by grafting flavonoids on the surface, an excellent mite repellent effect is imparted.

Examples

[0022] Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited thereto.

[0023] [Example 1] [Preparation of Graphene Quantum Dots] Graphene oxide, hydrogen peroxide, and aqueous ammonia were reacted in a 1 L glass reactor, and the temperature was gradually raised from 70 °C to 90 °C and reacted for 4 hours to obtain a first graphene quantum dot aqueous dispersion. 50 mL of sodium hypophosphite solution was taken and placed in a 100 mL glass reactor. 9 g of the above graphene quantum dot aqueous dispersion was added, and after stirring until uniform, ultrasonic treatment was performed for 40 minutes. The glass reactor was placed in a microwave reactor, the temperature was set to 150 °C, the microwave output was set to 600 W, and microwave treatment was performed for 30 minutes. After the obtained liquid was cooled to room temperature, it was centrifuged at 9000 r / min for 10 minutes in a high-speed centrifuge, the supernatant was removed, and a second graphene quantum dot aqueous dispersion was obtained. The above second graphene quantum dot aqueous dispersion and mugwort extract were mixed in a glass container at a mass ratio of 70:30, and ultrasonic treatment was performed for 2 to 5 hours with an ultrasonic rod of 200 watts or more under the conditions of 185 to 200 °C to obtain a graphene quantum dot aqueous dispersion in which flavonoids were chemically bonded to the surface. 3.5 times the mass of deionized water was added to the above graphene quantum dot aqueous dispersion in which flavonoids were chemically bonded to the surface, and filtration was performed three times to obtain a purified product of the dispersion. Freeze-drying treatment was performed at -70 °C for 7 hours using a freeze dryer to obtain a graphene quantum dot powder having an anti-mite function and a particle size of 10 nm or less.

[0024] [Preparation of Masterbatch] 2.5 parts by mass of the graphene quantum dot powder having the anti-mite function and a particle size of 10 nm or less and 2 parts by mass of graphene having a particle size of 500 nm or less were mixed in a negative pressure supercritical mixing device, and preliminary mixing was performed for 2.5 hours under the conditions of a temperature of 55 °C and a rotation speed of 16,000 R / min to obtain a two-component graphene powder uniformly dispersed. Polyester chips with a viscosity of 1.0 or more were pulverized in a liquid nitrogen pulverizer at -169°C for 45 minutes to obtain matrix powder. The above two-component graphene powder, 93 parts by mass of the above matrix powder, and 2.5 parts by mass of dopamine were put into a mixing device (independently developed by the company) and mixed until uniform to obtain functional powder. The stirring speed was 35 - 65 r / min, the stirring time was 1.5 - 2 hours, and the heating temperature was 45 - 85°C. The above functional powder was put into an ultra-high torque co-directional high-performance twin-screw granulator (CX-HO26, manufactured by Ruiya Co., Ltd.) and granulated at a temperature of 155 - 285°C for 15 minutes to obtain a semi-finished product of masterbatch. At a temperature of 105°C, a drying machine was used for 3 hours of crystal drying treatment to obtain a masterbatch with a water content of less than 1% and a uniform distribution.

[0025] <Preparation of Fibers> The above masterbatch was put into a drum drying circulator and dried at a temperature of 85°C for 8 hours so that the water content of the masterbatch became 1% by mass or less. The above masterbatch and polyester chips with a viscosity of 1.0 or more were mixed in a negative pressure pump circulation mixer to obtain a mixed melt. The mixing time was 2 - 2.5 hours, the mixing temperature was 85°C, the pump pressure was 2.5 standard atmospheres, and the circulation mixing speed was 45 r / min. The above mixed melt was sent to a spinning machine by a metering pump through a negative pressure extraction device and spun at a temperature of 150 - 285°C and a pressure of 20 - 28 standard atmospheres, and cooled through a spinning sleeve to obtain continuous filament fibers with a fineness of 0.5 Dex or less.

[0026] [Example 2] Instead of the material composition of 2.5 parts by mass of graphene quantum dot powder with an anti-mite function and a particle size of 10 nm or less, 2 parts by mass of graphene with a particle size of 500 nm or less, 93 parts by mass of matrix powder, and 2.5 parts by mass of dopamine, 3 parts by mass of graphene quantum dot powder with an anti-mite function and a particle size of 10 nm or less, 3 parts by mass of graphene with a particle size of 500 nm or less, 91 parts by mass of matrix powder, and 3 parts by mass of dopamine were used. Otherwise, in the same manner as in Example 1, a masterbatch and fibers containing two components of graphene quantum dots and graphene were obtained.

[0027] [Example 3] Instead of the material composition of 2.5 parts by mass of graphene quantum dot powder with an anti-mite function and a particle size of 10 nm or less, 2 parts by mass of graphene with a particle size of 500 nm or less, 93 parts by mass of matrix powder, and 2.5 parts by mass of dopamine, 5 parts by mass of graphene quantum dot powder with an anti-mite function and a particle size of 10 nm or less, 4 parts by mass of graphene with a particle size of 500 nm or less, 86 parts by mass of matrix powder, and 5 parts by mass of dopamine were used. Otherwise, in the same manner as in Example 1, a masterbatch and fibers containing two components of graphene quantum dots and graphene were obtained.

[0028] In the examples, various physical properties were measured or calculated as follows.

[0029] The particle size of the graphene quantum dots produced in Example 1 was detected using a transmission electron microscope (Talos STEM, manufactured by Thermo Fisher Scientific). The results are shown in Figure 1.

[0030] According to JIS L 1096 Method A (constant temperature method), the heat storage and heat preservation performance of the fibers containing two components of graphene quantum dots and graphene produced in Examples 1 to 3 was detected. The results are shown in Table 1.

[0031] According to the 45-degree parallel re-radiation method, which is a test method for evaluating the heat re-radiation characteristics certified by the Far Infrared Association, the heat re-radiation performance of the fibers containing the two components of graphene quantum dots and graphene produced in Examples 1 to 3 was detected. The results are shown in Table 1.

[0032] According to the bacterial liquid absorption method of JIS L 1902, the antibacterial activity of the fibers containing the two components of graphene quantum dots and graphene produced in Examples 1 to 3 was detected. The results are shown in Table 1.

[0033] According to the glass tube A method of JIS L 1920, the anti-mite performance of the fibers containing the two components of graphene quantum dots and graphene produced in Examples 1 to 3 was detected. The results are shown in Table 1.

[0034] According to the test method for the chargeability of woven and knitted fabrics of JIS L 1094, the antistatic performance of the fibers containing the two components of graphene quantum dots and graphene produced in Examples 1 to 3 was detected. The results are shown in Table 1.

[0035] Figure 1 shows the particle size of the graphene quantum dots produced in Example 1. In the image taken by the transmission electron microscope in Figure 1 (TEM measurement photo), the graphene quantum dots are shown as black dots. Using the particle size distribution measurement function of the transmission electron microscope, the particle size and distribution of the graphene quantum dots were measured. As shown in Figure 1, the particle size of the graphene quantum dots was 10 nm or less, and the graphene quantum dots with a particle size of about 3 nm accounted for about 70% of the whole.

[0036]

Table 1

[0037] Table 1 shows the performance parameters of the fibers containing the two components of graphene quantum dots and graphene produced in Examples 1 to 3. As shown in Table 1, the fibers containing the two components of graphene quantum dots and graphene of the present invention have good heat storage and heat preservation properties, and the measured value of the heat re-radiation property is greater than 5% and excellent. The antibacterial activity is 2.2 or more, and it was also found to have acarid-proof performance. In addition, the fibers containing the two components of graphene quantum dots and graphene of the present invention were found to have an antistatic effect.

[0038] The present invention has been described in detail based on the above-described embodiments, but these are only a part of the embodiments of the present invention, not all embodiments. Also, it should be understood that other embodiments can be obtained based on these embodiments, and all of these embodiments belong to the protection scope of the present invention.

Claims

1. A method for producing graphene quantum dots with a particle size of 10 nm or less, comprising: a first aqueous dispersion preparation step of reacting graphene oxide, hydrogen peroxide, and aqueous ammonia to prepare a first graphene quantum dot aqueous dispersion; a second aqueous dispersion preparation step of adding a reducing agent and a phosphate to the first graphene quantum dot aqueous dispersion, irradiating with microwaves in the range of 100 to 200 °C, and preparing a second graphene quantum dot aqueous dispersion in which graphene quantum dots with a particle size of 10 nm or less are dispersed; and a freeze-drying step of freeze-drying the second graphene quantum dot aqueous dispersion to obtain graphene quantum dots with a particle size of 10 nm or less. A method for producing graphene quantum dots with a particle size of 10 nm or less.

2. The method for producing graphene quantum dots with a particle size of 10 nm or less according to claim 1, further comprising a flavonoid reaction step of mixing the second graphene quantum dot aqueous dispersion and a flavonoid, performing ultrasonic treatment at 185 to 200 °C for 2 to 5 hours, and reacting the graphene quantum dots with the flavonoid.

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