KR20150076632A - Graphene composite and method for preparing the same - Google Patents

Abstract

Disclosed are a graphene composite and a manufacturing method thereof, which can improve dispersibility and electrical conductivity of graphene using a composite comprising graphene, a cationic polymer, and an anion amphiphilic surfactant. The graphene composite comprises: a cationic polymer comprising at least one alkyl amine generated by polymerization between the same species or the different species of a cationic monomer certainly comprising at least one nitrogen (N) atom; graphene formed by reducing or delaminating a carbon compound selected from the group consisting of a graphene oxide, graphite, and expanded graphite; and an anion amphiphilic surfactant having amphiphilicity of hydrophilicity and hydrophobicity.

Description

Graphene composite and method for preparing same

The present invention relates to a graphene composite and a manufacturing method thereof, and more particularly, to a graphene composite and a method for producing the graphene composite using the composite comprising graphene, a cationic polymer and an anionic amphiphilic surfactant, And a method for producing the same.

A graphene is a carbon crystal having a two-dimensional sheet shape in which carbon atoms are connected in a hexagonal honeycomb shape, and a plurality of plate type graphenes are laminated to form a graphite. Thus, when graphite is exfoliated, it is possible to obtain a plate-like graphene composed of a single layer or a plurality of layers. Graphene is a material having both metallic and non-metallic properties. It has good electrical conductivity and thermal conductivity as the nature of the metal, and has high thermal stability and chemical inertness as a non-metallic property. Graphene can be applied to various applications such as electric devices, batteries, fuel cells, refractory materials and the like.

Graphene is usually manufactured in a top down manner in which graphite or natural graphite is peeled off by oxidative expansion using an oxidizing agent and an intercalating agent. The graphene is coated on the edge and the surface of the graphene with epoxy there are functional groups containing a large number of oxygen (O) atoms such as an epoxy group, a hydroxyl group, a carbonyl group, or a carboxylic acid group, Graphene oxide (GO) is well dispersed in various kinds of polar organic solvents including water, but it is not dispersed in a non-polar solvent and lowers the high electrical conductivity inherent in graphene, so that it has non-conductive properties Depending on the polarity of the solvent, the kind and content of the polymer or monomer to be polymerized with the additive to be added to the graphene and the functional group of the graphene must be changed. In addition, since the solvent capable of dissolving and dispersing graphene oxide is extremely limited, there is a problem in dispersibility. As a method for solving such a problem, graphene is dispersed in a solvent, Functional groups can be added for use as fillers, but in this case there is a problem of electrical conductivity dropping. In addition, since the functional group existing at the edge of the graphene is more abundant than the functional group present at the surface, the functional group is disrupted during reduction, and a portion having a negative charge is present at the edge of the graphene, There is a drawback that occurs.

On the other hand, there are many patents relating to the bonding of reduced graphene and cationic polymer. Korean Patent Publication No. 2002-0091709 discloses a composite material in which polynorbene and graphene oxide are bonded, Amine compound, etc., and the manufacturing method and application field. U.S. Patent Publication No. 2012-0261612 discloses the dispersion of a graphene-based material modified with a polyionic liquid, in which the ionic liquid used differs in structure and material from the present invention, It is also different. Japanese Patent Application Laid-Open No. 2013-079176 discloses a modified graphene, a film, and a molded article, which are produced by mixing a raw material such as graphene oxide modified with a phenylhydra derivative containing a sulfo group, There is a difference in the method. Also, US Patent Publication No. 2012-0328785 discloses a polyimide nanocomposite and a manufacturing method thereof, and there is a difference in raw materials and manufacturing methods, such as using graphene oxide modified with gamma aminobutyric acid. (See also Chemical Engineering Science 85 (2013) 30-37p, Nature. Nanotechnology vol. 3 (2008) 101-105p, Langmuir article 2010, 26 (23), 17943-17948p)

An object of the present invention is to provide a graphene composite which can improve the electrical conductivity of graphene and a method for producing the same.

Another object of the present invention is to provide a graphene composite which can improve the dispersibility of graphene in a wide range of polar and nonpolar solvents, and which can add a high amount of graphene, and a method for producing the same.

It is still another object of the present invention to provide a graphene composite which can prevent aggregation occurring in graphene and improve the dispersibility of graphene, and a method for producing the same.

In order to achieve the above object, the present invention relates to a cationic polymer produced by polymerization between homo- or hetero-cationic monomers which necessarily contain at least one nitrogen (N) atom, and which contains at least one alkylamine; Graphene formed by reduction or exfoliation of a carbon compound selected from the group consisting of graphene oxide, graphite, and expanded graphite; And an anionic amphiphilic surfactant having hydrophilic and lipophilic amphiphilic properties.

The present invention also provides a method for preparing a cationic polymer, comprising: (a) preparing a cationic polymer having at least one alkylamine by polymerization reaction of a homo- or hetero-cationic monomer containing at least one nitrogen atom; (b) reducing or exfoliating a carbon compound selected from the group consisting of graphene oxide, graphite, and expanded graphite to produce graphene; (c) dissolving and stirring the cationic polymer and graphene in deionized water to prepare a graphene-cationic polymer conjugate; And (d) adding an anionic amphoteric surfactant to the graphene-cationic polymer conjugate, followed by stirring and drying the graphene-cationic polymer conjugate.

The graphene composite according to the present invention and the method for producing the graphene composite according to the present invention are characterized in that a pure graphene having hydrophobic properties is not dissolved in most of the solvents and the solubility is changed by attaching a functional group to the graphene, It is possible to produce graphite, graphen oxide and expanded graphite from high-purity graphene by a simple process excluding the functionalization process of graphene for improving dispersibility, and to separate and disperse high-purity graphene to improve electrical characteristics have. That is, by using a cationic polymer and an anionic amphiphilic surfactant in expanded graphite or graphene, they are highly peeled by the interaction of the electric attraction with the π-π interaction and easily dispersed in various polar solvents Graphene composites can be produced, and thus the electrical conductivity and dispersibility of graphene can be improved. It is also possible to prevent aggregation occurring in graphene.

1 is a flow chart for explaining a method of manufacturing a graphene composite according to an embodiment of the present invention;
2 is a schematic view schematically illustrating a state in which a graphene composite is manufactured according to an embodiment of the present invention.
FIG. 3 is a graph comparing electrical conductivities of the ink using the graphene composite and the ink prepared in the comparative example, according to an embodiment of the present invention.
FIG. 4 is an image (A) showing the printability of the ink to which the graphene composite is applied and images (B and C) showing the printability of the ink prepared in the comparative example, according to an embodiment of the present invention.

Hereinafter, the present invention will be described in detail.

The graphene composites according to the present invention are capable of improving the dispersibility and electrical conductivity of graphene and are produced by polymerization between homo- or hetero-cationic monomers containing at least one nitrogen (N) atom, Graphene formed by reducing or exfoliating a carbon compound selected from the group consisting of a cationic polymer, graphene oxide, graphite and expanded graphite, and an anionic amphiphilic interface having a hydrophilic and lipophilic amphiphilic Active agent.

The cationic polymer used in the graphene composite according to the present invention combines with graphene reduced to a negative charge with two characteristics of electric attraction and π-π interaction, whereby the graphene is peeled with high purity to improve the electric conductivity . On the other hand, the cationic polymer is produced by polymerization of a cationic monomer, and may be varied depending on the cationic monomer to be used.

 [Chemical Formula 1]

In Formula 1, R ₁ is an aliphatic hydrocarbon group having 1 to 15 carbon atoms, preferably an alkyl group having 1 to 10 carbon atoms, and R ₂ is an aromatic ring having 6 to 25 carbon atoms, preferably 8 to 20 carbon atoms, And n is the number of the repeating unit of the polymer represented by the formula (1), is a natural number of 1 to 100, preferably 3 to 70, more preferably 5 to 30, The mixing ratio of R ₁ and R ₂ in the polymer is 1: 9 to 9: 1, preferably 3: 7 to 7: 3, more preferably 4: 6 to 6: 4.

,

,

,

,

및

등이 있다(한편, 상기 예시들에서 굴곡선(

)은 연결부(connecting bond)를 나타낸다).
In Formula 1, specific examples of R ₁ include methyl, ethyl, propyl, isobutyl, pentyl, hexyl, nonyl, and dodecyl (dodecyl), and specific examples of R < ₂ &

,

,

,

,

And

And the like (in the above examples,

) Represents a connecting bond).

On the other hand, the cationic polymer is prepared by polymerizing the same or different cationic monomers, and the mechanism by which the cationic polymer is produced by polymerization of the cationic monomers is shown in the following Reaction Scheme 1.

 [Reaction Scheme 1]

The cationic monomer must contain at least one nitrogen (N) atom, whereby the polymer produced by homopolymerization or homopolymerization of a cationic monomer must contain at least one alkyl amine .

), 2-(1-나프탈레닐메틸) 아지리딘(2-(1-naphthalenylmethyl) aziridine,

), 2-에틸-2-페닐메틸 아지리딘(2-ethyl-2-phenylmethyl aziridine,

), 2-(4-메틸페닐) 아지리딘(2-(4-mehtylphenyl) aziridine,

), 2-에틸-2-페닐 아지리딘(2-ehtyl-2-phenyl aziridine,

), 2-(1-나프탈레닐) 아지리딘(2-(1-naphthalenyl) aziridine,

), 2-나프탈레닐메틸 아지리딘(2-naphthalenylmethyl aziridine), 2-메틸 아지리딘(2-methyl aziridine), 노말-토실 아지리딘(n-tosyl aziridine), 1-(벤질설포닐) 아지리딘(1-(benzylsulfonyl) aziridine) 및 1-(2-시아노에틸) 아지리딘(1-(2-cyanoethyl) aziridine) 등이 있다.
Specific examples of the cationic monomer include 2-phenylmethyl aziridine,

), 2- (1-naphthalenylmethyl) aziridine, 2- (1-naphthalenylmethyl) aziridine,

), 2-ethyl-2-phenylmethyl aziridine,

), 2- (4-methylphenyl) aziridine, 2- (4-mehtylphenyl) aziridine,

), 2-ethyl-2-phenyl aziridine,

), 2- (1-naphthalenyl) aziridine, 2- (1-naphthalenyl) aziridine,

), 2-naphthalenylmethyl aziridine, 2-methyl aziridine, n-tosyl aziridine, 1- (benzylsulfonyl) aziridine (1-benzylsulfonyl) aziridine and 1- (2-cyanoethyl) aziridine.

The graphene formed by the reduction or exfoliation of the carbon compound selected from the group consisting of graphene oxide, graphite and expanded graphite used in the graphene composite according to the present invention has a negative charge on the surface, , Reducing the graphene oxide, or peeling the graphite and the expanded graphite, and it is most preferable to reduce the graphene oxide. As the reducing agent to be used, a typical one capable of reducing graphene oxide is, for example, a hydrazine solution, sodium borohydride, ascorbic acid, phenylhydrazine iodide, and mixtures thereof.

Next, the anionic amphiphilic surfactant used in the graphene composite according to the present invention may be added to the graphene-cationic polymer conjugate composed of the cationic polymer and graphene to prepare a graphene composite having a multilayer structure Since the anionic amphiphilic surfactant has hydrophilicity and lipophilicity, when it is added to the graphene-cationic polymer conjugate, it is easy to disperse in various polar solvents and dispersion at a high concentration is possible.

등의 인산을 포함하는 모노 에스터(mono ester) 및

등의 인산을 포함하는 디에스터(diester)를 사용할 수 있다. 여기서, M⁺는 Na⁺ 및 Ca²⁺ 등의 알칼리 금속이거나, 알칼리 토금속 이온이며, R은 각각 독립적으로 C_nH_2n+1의 구조를 갖는 것으로서, n은 0 내지 15, 바람직하게는 0 내지 12, 더욱 바람직하게는 1 내지 12이다.
The anionic amphiphilic surfactant may be any conventional anionic surfactant having hydrophilic and lipophilic (or hydrophobic) amphiphilic properties,

Mono-ester containing phosphoric acid such as < RTI ID = 0.0 >

Or a phosphoric acid-containing diester may be used. Here, M ⁺ is an alkali metal such as Na ⁺ and Ca ²⁺ , or an alkaline earth metal ion, and each R independently has a structure of C _n H _{2n + 1} , where n is 0 to 15, 12, and more preferably 1 to 12.

Next, a method for producing the graphene composite according to the present invention will be described.

The method for producing a graphene composite according to the present invention comprises the steps of: (a) polymerizing a homo- or hetero-cationic monomer containing at least one nitrogen (N) atom to produce a cationic polymer having at least one alkylamine (B) reducing or exfoliating a carbon compound selected from the group consisting of graphene oxide, graphite and expanded graphite to produce graphene, (c) contacting the cationic polymer and graphene to deionized water (D) adding an anionic amphoteric surfactant to the graphene-cationic polymer conjugate, followed by agitation and drying. The graphene-cationic polymer conjugate may be prepared by dissolving and stirring the graphene-cationic polymer conjugate.

FIG. 1 is a flow chart for explaining a method of manufacturing a graphene composite according to an embodiment of the present invention. FIG. 2 is a schematic view schematically showing a state in which a graphene composite is manufactured according to an embodiment of the present invention. to be. 1 and 2, a method of manufacturing the graphene composite will be described in detail. First, a method for producing the cationic polymer will be described. First, 50 to 90% by weight and 10 to 50% by weight of two kinds of homo- or hetero-cationic monomers each containing at least one nitrogen (N) (S 10) are mixed in 60 to 80% by weight and 20 to 40% by weight, more preferably 60 to 70% by weight and 30 to 40% by weight, in deionized water. Next, a polymerization initiator of an acid component is added to the cationic monomer mixture dissolved in the deionized water to initiate the polymerization reaction (S 12), and at the time of polymerization, the polymerization reaction is initiated at 30 to 100 ° C , Preferably 40 to 70 占 폚, more preferably 50 占 폚. When polymerization is performed for a predetermined time, the pH of the polymerized polymer is adjusted to neutral (pH 7) by adding a compound such as sodium hydroxide having a basic property to terminate the polymerization reaction (S 14). After completion of the polymerization reaction, the polymerized polymer is dried, and the dried polymer is dissolved in a solvent such as ethanol. Then, a substance such as sodium chloride which has remained in the polymerized product is removed by using a filter, After the precipitated polymer is precipitated in a solvent such as diethyl ether, it is dried in a vacuum at 40 to 80 ° C, preferably at 50 to 70 ° C for 2 to 5 hours, preferably for 3 to 4 hours To prepare a cationic polymer containing at least one alkylamine (S 16). On the other hand, the weight average molecular weight (Mw) of the cationic polymer is 5,000 to 50,000, preferably 5,000 to 20,000, and more preferably 10,000 to 15,000. In order to control the weight average molecular weight, Or a polymerization terminator is used.

Next, a description will be given of a method for producing the graphene. When graphene oxide is used among carbon compounds selected from the group consisting of graphene oxide, graphite and expanded graphite, hydrazine solution (hydrazine solution) is added to prepare a mixed solution. In this case, the content of the graphene oxide and the reducing agent is 0.1 to 3 wt% and 1 to 15 wt%, respectively (the other content is a solvent). For example, the graphene oxide and the reducing agent are used in a ratio of 1: 5 to 1: 10 < / RTI > by weight. On the other hand, if the content of the graphene oxide is less than 0.1% by weight, the yield may be excessively lowered. If the content of the graphene oxide is more than 3% by weight, it may be difficult to maintain dispersibility, %, The time required for the reduction may be increased. If it is more than 15 wt%, the impurities may act as impurities and the electrical conductivity may be lowered, and a washing process may be further required . Next, the mixed solution is concentrated under reduced pressure using a rotary evaporator at 50 to 80 ° C, preferably 60 to 70 ° C for 3 to 6 hours, preferably 4 to 5 hours, dispersed graphene can be produced and graphite or expanded graphite among the carbon compounds selected from the group consisting of graphene oxide, graphite and expanded graphite is used, the graphite or expanded graphite can be physically The graphene is prepared (S 20), which may include peeling and dispersing (if necessary, peeling and then dispersing).

On the other hand, the production of the cationic polymer and the production of graphene may be reversed and are only listed in the order shown in Fig.

Next, the method of forming the graphene-cationic polymer conjugate will be described. First, the cationic polymer prepared in (S 14) shown in FIG. 1 and the graphene prepared in (S 20) water) (S30). At this time, the cationic polymer and graphene have a mixing ratio of 5 to 20:80 to 95, preferably 5 to 15:85 to 95, and more preferably 10 to 15:85 to 90. Then, the cationic polymer and graphene dissolved in the deionized water are stirred at room temperature for 10 to 60 minutes, preferably 20 to 40 minutes to prepare a graphene-cationic polymer conjugate (S 32).

Unlike conventional polyethyleneimine (PEI, polyethylene imine) which has been attached to the adherend only by an electrical force, the cationic polymer has an additional influence on electrical attraction and As two characteristics of the π-π interaction, it is possible to form a graphene complex having improved electrical conductivity by bonding to graphene reduced to a negative charge and peeling the graphene with high purity, and it is possible to prevent aggregation of graphene have.

Next, a step of preparing the graphene composite according to the present invention by adding an anionic amphoteric surfactant to the graphene-cationic polymer conjugate prepared in the step (S32) will be described. The anionic amphipathic surfactant Is added in an amount of 10 to 30 parts by weight, preferably 10 to 25 parts by weight, more preferably 15 to 25 parts by weight, per 100 parts by weight of the graphene-cationic polymer conjugate composed of the cationic polymer and graphene Followed by stirring for 20 to 40 minutes, preferably 25 to 35 minutes. Next, when the stirring is completed, the resultant is dried in a vacuum state at 30 to 60 ° C, preferably 40 to 50 ° C, for 2 to 5 hours, preferably 3 to 4 hours to obtain a graphene-cationic polymer conjugate- A graphene composite having a multi-layer structure of a surfactant can be prepared (S34).

The graphene composite according to the present invention can be used as a filler applicable not only to the manufacture of ESD, EMI shielding, conductive composite and conductive pellets, but also to various fields. For example, ESD ink / paste conductive filler, EMI shielding ink / paste conductive filler, heat dissipation ink paste filler, ESD and EMI shielding, heat dissipation and extrusion Product conductive fillers, strength reinforcing fillers, and conductive transparent film fillers. Ink / paste fillers can be used to form high-density inks, and also to polymer composites. Can be used. On the other hand, according to the field to which the graphene composite according to the present invention is applied, the content of graphene contained in the graphene composite may vary, and when the graphene composite is used for ESD, the graphene content is 0.05 to 4 0.1 to 50 wt% when used for EMI, and 0.1 to 99 wt% when used for heat radiation.

Hereinafter, the present invention will be described in more detail with reference to specific examples. The following examples illustrate the present invention and are not intended to limit the scope of the present invention.

[Preparation Example 1] Preparation of cationic polymer

(Sigma-Aldrich, USA) and 2-methyl aziridine (Sigma-Aldrich, USA) were mixed in a weight ratio of 60:40 (weight%: weight %) Was dissolved in 500 ml of deionized water. Subsequently, 5 ml of HCl (Purity: 35%) as a polymerization initiator (Samchun Chemical Co., Ltd.) was added, and stirring was carried out for 24 hours with a stirrer (rpm: 300) . Then, 5 ml of sodium hydroxide having a purity of 98% (Sigma-Aldrich, USA) was added to adjust the pH to neutral (pH 7) to terminate the polymerization reaction. Then, the polymerized polymer prepared by the above polymerization at 50 DEG C and 10 mbar was dried for 24 hours, and the dried polymer was dissolved in 150 mL of ethanol having a purity of 96% (Sigma-Aldrich, USA) To remove sodium chloride remaining in the polymer. Finally, the polymer having the residual material removed was precipitated in 200 ml of diethyl ether (Sigma-Aldrich, USA) having a purity of 99%, and then dried at 50 DEG C under vacuum for 3 hours to obtain a polymer having a weight average molecular weight of 13,900 g / mol of a cationic polymer.

[Preparation Example 2] Preparation of graphene

First, 100 ml of a hydrazine solution (Sigma-Aldrich, USA) having a purity of 35% as a reducing agent was added to 50 ml of a dispersed graphene oxide solution (content of graphene oxide in solution: 2%, Anstron, USA) , A graphene and a reducing agent. Next, the prepared mixed solution was concentrated under reduced pressure at 60 캜 for 4 hours by a rotary evaporator, and then subjected to reduction treatment to prepare water-dispersed graphene having 4% by weight of graphene powder. Here, it was found that the surface potential of the produced graphene was -25 mV, and the dispersibility was maintained in the aqueous solution state.

[Preparation Example 3] Preparation of graphene-cationic polymer conjugate

First, 3 g of the cationic polymer prepared in Preparation Example 1 and 675 g of the graphene solution prepared in Preparation Example 2 were dissolved in 1 L of deionized water. Then, the cationic polymer and graphene dissolved in the deionized water were stirred at a room temperature for 30 minutes with a stirrer (rpm: 2,000) to prepare a graphene-cationic polymer conjugate.

[Preparation Example 4] Preparation of a graphene composite comprising graphene-cationic polymer-anionic amphipathic surfactant

To 30 g of the graphene-cationic polymer conjugate prepared in Preparation Example 3, 6 g of an anionic amphoteric surfactant was added in an amount of 20 parts by weight based on 100 parts by weight of the graphene-cationic polymer conjugate, and the mixture was stirred for 30 minutes. . After completion of the stirring, the powder was dried at 40 ° C under vacuum for 3 hours to prepare a powder-form graphene composite.

[Examples 1 to 4, Comparative Examples 1 to 12] Preparation of ink applying graphene composite

The graphene complex, propylene glycol monomethyl ether acetate (PGMEA) and polyester resin prepared in Preparation Example 4 were mixed for about 30 minutes as shown in the composition of Table 1 below, And zirconia balls having a size of 1.2 mm were added and dispersed in a mixer (DAS-200, Germany) for 30 minutes to prepare an ink.

[Example 3, Comparative Examples 3, 7, 10] Evaluation of dispersibility of ink according to polarity for solvent

The inks prepared in the examples and comparative examples in Table 1 were dispersed in various solvents shown in Table 2 below and the dispersibility was compared. In the following Table 2, ⊚ indicates excellent dispersibility, ◯ indicates excellent, Δ indicates average dispersibility, and × indicates dispersibility below average.

As shown in the above Table 2, in the case of the ink prepared in Example 3, the polar and non-polar functional groups included in the anionic amphoteric surfactant still exist in a good state in both polar and non-polar solvents even after a lapse of time On the other hand, in the case of the inks prepared in Comparative Examples 3, 7 and 10 (using SPAN-40 and / or TWEEN-80, which is a conventional surfactant), toluene, cyclohexene and hexane, which are non-polar solvents, (Precipitation occurred). Therefore, it can be seen that the ink or the like to which the graphene composite according to the present invention is applied has excellent dispersibility in a polar solvent as well as a non-polar solvent.

[Examples 1 to 4 and Comparative Examples 1 to 4 and 9 to 12] Evaluation of electrical conductivity of ink using a graphene composite

The inks to which the graphene composites prepared in Examples 1 to 4, Comparative Examples 1 to 4 and Comparative Examples 9 to 12 in Table 1 were applied were made into polyethylene terephthalate (PET) using an applicator, The film was applied to a thickness of about 10 micrometers (탆), dried in a hot-air oven at 130 캜 for 30 minutes, and then measured for surface resistance using a 4-point probe. FIG. 3 is a graph comparing electrical conductivities of the ink using the graphene composite and the ink prepared in the comparative example, according to an embodiment of the present invention. As shown in FIG. 3, when the graphene content is the same, the ink to which the graphene composite according to the present invention is applied (Examples 1 to 4 above) is about 40 to 60% (In the case of the TWEEN-80 surfactant prepared in Comparative Examples 5 to 8), agglomerates were generated in the solvent of propylene glycol monomethyl ether acetate (PGMEA), and the surface resistance Was not measured). Therefore, it can be seen that the ink using the graphene composite according to the present invention has excellent electrical conductivity.

[Example 2, Comparative Examples 2 and 10] Evaluation of printing property of ink using graphene composite

FIG. 4 is an image (A) showing printability of the ink to which the graphene composite is applied and images (B and C) showing the printability of the ink prepared in the comparative example, according to an embodiment of the present invention. All of FIGS. 4A, 4B and 4C are images obtained by magnifying the surface of the film at a magnification of 40, and the content of graphene contained in the ink used is also 0.25% by weight. As shown in FIG. 4, in the case of the image (A) showing the printability of the ink using the graphene composite according to the present invention (Example 2), the transmittance was 85.2% In the case of the images (B and C) showing the printability of the inks produced in the comparative examples (Comparative Examples 2 and 10), the transmittance was only 74.1% and 63.9%, respectively, That is, aggregation occurred. Therefore, when the ink using the graphene composite according to the present invention is used, cohesion is prevented and printing is improved.

Claims (11)

A cationic polymer produced by polymerization between homo- or hetero-cationic monomers that necessarily contain at least one nitrogen (N) atom, and which necessarily contains at least one alkyl amine;
Graphene formed by reduction or exfoliation of a carbon compound selected from the group consisting of graphene oxide, graphite, and expanded graphite; And
A graphene complex comprising an anionic amphiphilic surfactant having hydrophilic and lipophilic amphiphilic properties. The graphene composite according to claim 1, wherein the cationic polymer is represented by the following formula (1).
[Chemical Formula 1]

Wherein R ₁ is an aliphatic hydrocarbon group having 1 to 15 carbon atoms, R ₂ is a hydrocarbon group containing at least one aromatic ring having 6 to 25 carbon atoms, and n is a repeating unit of the polymer represented by Formula 1 The number of units is a natural number of 1 to 100, and the mixing ratio of R ₁ and R ₂ in the polymerized polymer is 1: 9 to 9: 1. The method according to claim 2, R ₁ of formula (I) will be selected from methyl, ethyl, propyl, isobutyl, pentyl, hexyl, nonyl, and indeed the group consisting of alkyls, R ₂ is

,

,

,

,

And

≪ RTI ID = 0.0 > (In the above examples,

) Represents a connection portion). The composition of claim 1, wherein the cationic monomer is 2-phenylmethyl aziridine (

), 2- (1-naphthalenylmethyl) aziridine (

), 2-ethyl-2-phenylmethyl aziridine (

), 2- (4-methylphenyl) aziridine (

), 2-ethyl-2-phenyl aziridine (

), 2- (1-naphthalenyl) aziridine (

), 2- naphthalenylmethylaziridine, 2-methyl aziridine, n -tocyl aziridine, 1- (benzylsulfonyl) aziridine and 1- (2-cyanoethyl) aziridine A graphene composite that is one. The graphene complex of claim 1, wherein the reducing agent used to form the graphene is selected from the group consisting of hydrazine solution, sodium borohydride, ascorbic acid, phenylhydrazine iodide, and mixtures thereof. The composition of claim 1, wherein the anionic amphiphilic surfactant is

And

Wherein M ⁺ is an alkali metal or an alkaline earth metal ion and R is a structure of C _n H _{2n + 1} , wherein n is from 0 to 15. (a) polymerizing a homo- or hetero-cationic monomer containing at least one nitrogen atom to prepare a cationic polymer containing at least one alkylamine;
(b) reducing or exfoliating a carbon compound selected from the group consisting of graphene oxide, graphite, and expanded graphite to produce graphene;
(c) dissolving and stirring the cationic polymer and graphene in deionized water to prepare a graphene-cationic polymer conjugate; And
(d) adding an anionic amphoteric surfactant to the graphene-cationic polymer conjugate, and then stirring and drying the graphene-cationic polymer conjugate. The method according to claim 7, wherein the polymerization reaction in step (a) is performed at 30 to 100 ° C. [Claim 7] The method according to claim 7, wherein the cationic polymer and graphene in step (c) are combined at a mixing ratio of 5: 20: 80-95. [Claim 7] The method according to claim 7, wherein the anionic amphiphilic surfactant is added in an amount of 10 to 30 parts by weight based on 100 parts by weight of the graphene-cationic polymer conjugate. 8. The method of claim 7, wherein the cationic polymer has a weight average molecular weight of from 5,000 to 50,000.

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