KR101973663B1 - Synthesis method of graphene oxide - Google Patents

Abstract

The method of manufacturing the graphene oxide of the present invention, specifically, the method of controlling the amount of epoxy group introduced into the graphene, is a method of mixing the graphene with the peracetic acid and irradiating the microwave to control the amount of the introduced epoxy group, It is effective.

Description

Synthesis method of graphene oxide < RTI ID = 0.0 >

The present invention relates to a method of synthesizing an oxidized graphene, and more particularly, to a method for producing a novel oxidized graphene which significantly increases an epoxy group content by increasing an oxidation degree of graphene.

Graphite, one of the most widely known materials among carbon materials, is a material having a structure in which a plate-like two-dimensional structure of graphene having carbon atoms only in sp ² hybridization and connected in a hexagonal shape is layered. This two-dimensional structure of graphene has distinctive advantages over other carbon isotopes in terms of its unique physical properties as well as its electric-electronic applications and has been applied in various technical fields.

For example, it is possible to control semiconductor-conductor properties by using graphene, and it is possible to manufacture a wide variety of functional devices such as sensors and memories by utilizing the variety of chemical bonds of carbon. In addition, research on transparent electrodes, solar cells, pressure sensors, and the like in displays that can be applied to everyday life has been actively conducted. In such applications, there is a demand for modification of the electrical, physical, and chemical properties of graphene.

Therefore, by introducing or removing a specific oxygen-containing functional group to graphene in order to add or switch various characteristics to graphene to meet the requirements of each technical field, it is possible to control the content of specific functional groups introduced into graphene, Research is needed to make graphene.

Oxide graphene is generally produced by oxidizing graphite. For example, oxidized graphene is produced by oxidizing graphite using a modified Hummer's method (WS Hummers and RE Offeman, J. Am. Chem. Soc, 1958, 80, 1339.) do. When the oxygen-containing functional group is introduced on the surface of the graphene, the graphene oxide is influenced by the dispersibility in the solvent such as water depending on the kind and content of the introduced oxygen-containing functional group.

However, in order to control the properties such as the dispersibility of the graphene oxide, further studies have been carried out to further increase the degree of oxidation and increase the content of the specific oxygen-containing functional groups in graphene to control various properties of the graphene oxide More need.

Korean Published Patent Application No. KR2016-0088097A (Jul.

It is an object of the present invention to provide a method for producing graphene oxide having a higher content of epoxy groups by high oxidation which could not be achieved by conventional graphene oxidation methods.

In particular, it is an object of the present invention to provide a method for producing graphene oxide having a higher content of epoxy groups through oxidation of graphene oxide.

The present invention relates to a method for producing graphene oxide having a high polarity by significantly increasing the amount of epoxy group introduced into graphene.

The method for controlling the amount of epoxy group introduced into the graphene oxide of the present invention includes the steps of: a) preparing a mixture by mixing graphene and peracetic acid, and b) irradiating the mixture with microwave to introduce an epoxy group into the graphene .

In one embodiment of the present invention, the step b) may be carried out in an aqueous phase.

In one example of the present invention, the graphene in the step a) may be an oxide graphene.

In one embodiment of the present invention, the weight ratio of graphene to peracetic acid in step a) may be 1 to 10: 10,000.

In one embodiment of the present invention, the irradiation intensity of the microwave may be 30 to 2,000 W in the step b).

In one embodiment of the present invention, the irradiation time of the microwave in the step b) may be 10 seconds to 24 hours.

The method of manufacturing the graphene oxide of the present invention, specifically, the method of controlling the amount of epoxy group introduced into the graphene, is a method of mixing the graphene with the peracetic acid and irradiating the microwave to control the amount of the introduced epoxy group, It is effective.

The effects described in the following specification which are expected by the technical characteristics of the present invention and the potential effects thereof are handled as described in the specification of the present invention even if they are not explicitly mentioned in the present invention.

1 is an image schematically illustrating the introduction principle of specific oxygen-containing functional groups of graphene oxide.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a method for synthesizing an oxide graphene of the present invention will be described in detail with reference to the accompanying drawings.

The drawings described in the present invention are provided by way of example so that a person skilled in the art can sufficiently convey the idea of the present invention. Therefore, the present invention is not limited to the illustrated drawings, but may be embodied in other forms, and the drawings may be exaggerated in order to clarify the spirit of the present invention.

In addition, unless otherwise defined, technical terms and scientific terms used in the present invention have the same meanings as those of ordinary skill in the art to which the present invention belongs. In the following description and the accompanying drawings, Description of known functions and configurations that may unnecessarily obscure the subject matter will be omitted.

Also, the singular forms of the terms used in the present invention are intended to include plural forms unless otherwise indicated.

Also, units of% used unclearly in the present invention means weight percent.

The present invention relates to a process for the synthesis of graphene oxide having a higher content of epoxy groups. Specifically, the present invention relates to a method for controlling the amount of epoxy group introduced into graphene oxide. Specifically, in the present invention, the amount of epoxy group introduced into the graphene oxide (graphene oxide or graphene oxide) is controlled by maximizing or controlling the epoxy group content of the graphene oxide by mixing the mixture with graphene ≪ / RTI >

The peracetic acid is a raw material used to significantly increase the introduction amount of the avalanche period, and irradiation of the microwave is intended to more effectively induce an epoxy group introduction reaction.

Therefore, the epoxy group content of the graphene oxide can be controlled through the present invention and the content thereof can be maximized, so that the dispersibility characteristics of the graphene oxide can be efficiently controlled.

The method for controlling the amount of epoxy group introduced into the graphene oxide of the present invention includes the steps of: a) preparing a mixture by mixing graphene and peracetic acid, and b) irradiating the mixture with microwave to introduce an epoxy group into the graphene .

The use of peracetic acid in the present invention significantly increases the content of epoxy groups introduced into graphene. Especially when peracetic acid is not used, the content of epoxy group introduced into graphene is relatively low as compared with the case where peracetic acid is not used. For example, as a general oxide such as acetic acid, the content of epoxy group introduced into graphene is not relatively large as compared with that of peracetic acid, and the content of the epoxy group is remarkably lowered even with hydrogen peroxide which is a peroxide used for general oxidation.

In the present invention, the weight ratio of graphene to peracetic acid is not particularly limited as long as an oxygen-containing functional group such as an epoxy group can be introduced, and may be, for example, 1 to 10: 10,000.

In the present invention, the peracetic acid may be mixed with water as an aqueous solution, and thus an aqueous solution of peracetic acid may be mixed with graphene (or oxidized graphene), and an epoxy group may be introduced into the graphene by irradiation of a microwave. Therefore, the mixture of steps a) and b) may be subjected to an epoxy group introduction reaction by microwave irradiation in an aqueous phase further containing water. That is, in steps a) and b), the peracetic acid can be mixed and used in an aqueous solution of peracetic acid containing water. The concentration of the peracetic acid aqueous solution is not particularly limited, but may be, for example, 5 to 60% by weight aqueous solution of peracetic acid.

In the present invention, the mixture may further contain acetic acid to carry out an epoxy group introduction reaction. Thus, as a preferred example, the mixture may be used as a mixed acid solution comprising peracetic acid and acetic acid.

In the present invention, irradiation of the microwave is an essential component for introducing an epoxy group into graphene. When microwave irradiation is not performed, the amount of epoxy group introduced into graphene, particularly graphene oxide and the introduction efficiency Is very low.

In the present invention, the irradiation intensity of the microwave is not particularly limited as long as an oxygen-containing functional group such as an epoxy group can be introduced. For example, it may be 30 to 2,000 W, but the present invention is not limited thereto.

Also, the irradiation time of the microwave is not limited so long as an oxygen-containing functional group such as an epoxy group can be introduced. For example, it may be 10 seconds to 24 hours, but the present invention is not limited thereto. The microwave means an electromagnetic wave having a frequency of 300 MHz to 30 GHz.

The present invention may further comprise the step of c) recovering the oxidized graphene to which the epoxy group has been introduced after the micro-irradiation step, that is after step b). The step c) can be carried out by various known methods, but specifically, the graphene oxide can be separated and obtained by fractionation such as centrifugation. Further, after the step c), washing may be performed several times about one to five times until neutralization is performed using distilled water or the like.

In the present invention, graphene means a general graphene used in the art, and unoxidized graphene, reduced graphene, and oxidized graphene can be used. When the oxidized graphene graphene is used as the starting material of graphene in the present invention, the graphene, which is the starting material, is modified by the modified Hummer's method (WS Hummers and RE Offeman, J. Am. Chem. Soc., 1958, 80, 1339.).

The oxide graphene prepared by the method of the present invention can control the amount of a specific oxygen group during the synthesis process and thus can function as an oxide graphene based on the purpose of use, It is possible to improve various properties such as dispersibility and the like.

EXAMPLES Hereinafter, the present invention will be described in detail with reference to Examples. However, the present invention is described in more detail with reference to the following Examples. However, the scope of the present invention is not limited by the following Examples.

Oxidation Grapina  Produce

5 g of graphite was put into a round flask together with 2 g of NaNO ₃ and 375 ml of sulfuric acid. The entire flask was placed in an ice water bath, and the mixture was stirred at 250 rpm while keeping the temperature at 0 캜. 22 g of KMnO _{4 as} an oxidant was added little by little Followed by stirring for about 2 hours. Thereafter, the reaction mixture was poured into an oil bath at 30 DEG C and stirred for about 72 hours. At this time, the color of the solution changes to a form of a highly viscous slurry having a purple light. Then 700 ml of aqueous sulfuric acid solution (5 wt%) was added little by little and 20 ml of hydrogen peroxide was added to complete the reaction. Then, the oxidized graphene synthesized through a centrifugal separator was separated and unreacted graphite was removed using a glass filter. Thereafter, the cells were washed five times using 1M HCl aqueous solution and then washed with a third distilled water, washed with a centrifuge until the whole solution became neutral, and dried to prepare graft oxide (GO).

Oxidation of excessively introduced epoxy groups Grapina  Produce

20 mg of the above-prepared graphene oxide was added to 100 ml of an aqueous solution of peracetic acid (32 wt%) and stirred for 1 hour. The microwave of the frequency of 2.45 GHz was irradiated to the agitated mixture by microwave irradiation equipment for 7 hours at a power of 30 W to oxidize. After centrifugation at 20,000 rpm for 20 minutes, the supernatant was discarded, and the solution was washed five times with distilled water until the solution was neutralized. The resulting solution was dried to obtain GO_peracetic acid, which was excessively introduced with an epoxy group. .

The solution was dried in a vacuum oven and analyzed by X-ray photoelectron spectroscopy (XPS) to measure the degree of epoxy group introduction of the graft oxide into which the epoxy group was excessively introduced. Respectively.

[Comparative Example 1]

(GO_acetic acid) was prepared in the same manner as in Example 1 except that acetic acid was used instead of acetic acid. The result was analyzed by the same analytical method as in Example 1, and the results are shown in Table 1 below.

[Comparative Example 2]

(GO_H ₂ O) was prepared in the same manner as in Example 1 except that water (instead of acetic acid aqueous solution and water) was used in place of acetic acid. The resultant graphene oxide (GO_H ₂ O) was analyzed by the same analytical method as in Example 1 And the results are shown in Table 1 below.

Functional group Example 1 Comparative Example 1 Comparative Example 2 GO GO_peracetic acid GO_acetic acid GO_H ₂ O C-C 100 100 100 100 C-O 68 98 85 80

Table 1 shows the epoxy group (CO) content of the graphene oxide prepared in Example 1, Comparative Example 2 and Comparative Example 2. The value of the epoxy group (CO) is a value determined as a relative ratio of CC bonding Is a value determined on the basis of 100).

As a result, as shown in Table 1, in Comparative Example 1 where an oxide such as acetic acid instead of peroxide was used, the introduction amount of the epoxy group was as low as 85% based on the C-C bonding unit. Also, when water was used as in Comparative Example 2, it was less than 80% based on the C-C bonding unit. On the other hand, when the peracetic acid of Example 1 was used, the introduction amount of the epoxy group was 98% based on the CC bonding unit, which is much higher than that of Comparative Example 1 and Comparative Example 2. (Number of CO bonding units / number of CC bonding units )

Therefore, it can be seen that the introduction amount of the oxygen-containing functional group as a whole increases when graphene is oxidized and acetic acid is used, and in particular, the introduction amount of the epoxy group is remarkably increased.

Claims (6)

a) preparing a mixture comprising an oxidized graphene and an aqueous peracetic acid solution; and
b) introducing an epoxy group into the graphene by irradiating microwave to the mixture,
In the step b), the irradiation intensity of the microwave is 30 to 2,000 W and the irradiation time is 10 to 24 hours,
Wherein the peracetic acid aqueous solution contains peracetic acid in a concentration of 5 to 60% by weight, wherein the amount of epoxy group introduced in the oxygen-containing functional group is maximized. The method according to claim 1,
A method for synthesizing graphene grains in which the amount of epoxy groups introduced is maximized in an oxygen-containing functional group having a weight ratio of graphene and peracetic acid of 1 to 10: 10,000. delete delete delete delete

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