KR20180117855A - A catecholamine coating composition and coating method for the same - Google Patents

Abstract

The present invention provides a catecholamine coating composition for preparing a graphite composite. According to an embodiment of the present invention, a catecholamine coating composition forms a catecholamine layer on the graphite composite comprising nanoparticles formed on graphite and the catecholamine layer coated by including the nanoparticles. The catecholamine coating composition comprises a catecholamine-based compound and an oxidizer wherein the catecholamine-based compound is included in an amount of 0.1 to 6 mM. The catecholamine coating composition is evenly dispersed in a polymer matrix while minimizing agglomeration of particles of the catecholamine-based compound, and can expand a selection range of the polymer matrix by improving binding power with the polymer matrix having hydrophobic/nonpolar chemical properties. Further, the catecholamine coating composition of the present invention can be applied to various industrial fields since the catecholamine coating composition can efficiently use inherent excellent electrical and thermal properties of the graphite by preventing contact resistance in a vertical direction of the graphite when the catecholamine coating composition is coated on the graphite composite.

Description

Catecholamine coating composition and coating method thereof,

The present invention relates to a catecholamine coating composition, and more particularly, to a catecholamine coating composition and a catecholamine coating composition which are dispersed evenly in a polymer matrix with minimized agglomeration of particles to provide a graphite composite having excellent functions such as conductivity and thermal conductivity, And a coating method thereof.

Nanocomposites are materials that hybridize different kinds of materials to each other at the nano level by physical or chemical methods in order to overcome the limitations of physical properties of simple materials or simple materials and to obtain synergistic effects of multifunctional and high performance. Nanocomposite materials are classified by matrix and filler types. Nanocomposite materials, which are base materials, are composites produced by uniformly dispersing nano-sized fillers in polymer matrix. They are excellent in mechanical strength, It is a composite material that has excellent gas barrier properties, greatly improved abrasion resistance and heat resistance. When the nano-sized filler is filled in the polymer matrix to produce the composite material, the filler exhibits greatly improved physical properties with a smaller amount of filler than the graphite-polymer composite filled with the micro-sized filler.

Polymer nanocomposites based on these excellent properties are attracting attention as new materials expected to be applied in fields requiring high performance composite materials such as automobile industry, electronic industry and energy industry. At present, researches are being actively carried out to develop a high-functional polymer nanocomposite by charging a carbon-based filler such as carbonnanotube, carbon fiber and graphene into a polymer matrix, The filler is graphite.

Carbon nanostructures such as graphite have a large surface area compared with other nano additives (Na-MMT, LDH, CNT, CNF, EG, etc.) and have excellent mechanical strength, thermal properties and electrical properties. Has the advantage of having. Therefore, researches are actively conducted to develop a high performance functional graphite-polymer composite material excellent in conductivity and mechanical strength by filling graphite with a polymer matrix.

However, since carbon nanostructures such as graphite have a vander-walls force and a very stable chemical structure per se, it is difficult to uniformly disperse in a polymer matrix and an organic solvent, so that a graphite-polymer complex Although it is difficult to produce the material, the carbon nanostructure itself has excellent physical properties, and research on practical applicable techniques is very limited.

In order to solve such a problem, in Japanese Unexamined Patent Application Publication No. 10-2015-0110058, graphite having crystallized nano-metal on the surface thereof is coated with catecholamine such as polydodamine, And a composite material having improved dispersibility in a polymer matrix was obtained through the preparation of a graphite composite having enhanced bonding properties.

However, the graphite composite disclosed in the aforementioned patent publication shows improved dispersibility in the polymer matrix. However, the graphite composite exhibits a decrease in binding force with the polymer matrix due to the aggregation and agglomeration of graphite complexes due to an excessive content of catecholamines, , Which may result in deterioration of electrical and thermal properties, which limits application to new materials in various industrial fields and may also hinder utilization of excellent properties inherent to graphite

Thus, the present inventors have confirmed the optimum content of a catecholamine compound capable of solving the above problems while maintaining excellent properties inherent to the graphite composite, and completed the present invention.

Japanese Patent Application Laid-Open No. 10-2015-0110058

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is an object of the present invention to provide a catecholamine coating composition and a coating method thereof that can be uniformly dispersed in a polymer matrix.

Also, there is provided a catecholamine coating composition and a coating method thereof for producing a graphite composite having a catecholamine layer formed thereon, which has improved bonding strength with a polymer matrix having minor / nonpolar chemical characteristics, .

In addition, the present invention provides a graphite composite and a graphite-polymer composite material having improved electrical and thermal properties by minimizing contact resistance. Another object of the present invention is to provide a graphite-polymer composite material that can be applied in various industrial fields.

According to an aspect of the present invention, there is provided a catecholamine coating composition for forming a catecholamine layer on a graphite composite including nanoparticles formed on graphite and a catecholamine layer coated with the nanoparticles, , And the catecholamine compound is contained in an amount of 0.1 to 6 mM.

According to one embodiment of the present invention, the catecholamine is selected from the group consisting of dopamine, dopamine-quinone, alpha-methyldopamine, norepinephrine, epinephrine, And may be selected from the group consisting of alphamethyldopa, droxidopa, indolamine, serotonin, and 5-hydroxydopamine.

In addition, the oxidizing agent is iron (Fe ^{+ 3),} chromium (Cr ^{+ 6),} manganese (Mn ^{+ 7),} iodine (I ⁷⁺⁾ a metal selected from the group above, with hydrogen peroxide or Na ₂ S ₂ O ₈ consisting of It can be any one or more.

Also, the catecholamine coating composition for preparing the graphite composite further comprises an organic solvent, and the organic solvent is selected from the group consisting of alcohol, acetonitrile, 1,4-dioxane, acetone, dimethylformamide DMF), dimethylsulfoxide (DMSO), and N-methylpyrrolidone (NMP).

The oxidizing agent may be mixed in an amount of 5 to 20 parts by weight based on 100 parts by weight of the catecholamine compound.

The present invention also provides a method for coating a catecholamine coating composition comprising (1) preparing a catecholamine coating composition as described above, and (2) polymerizing the catecholamine coating composition to form a catecholamine layer in the graphite composite.

Between steps (1) and (2), the method may further include the step of hydrophilic modification using oxygen plasma.

The present invention also provides a graphite composite comprising nanoparticles formed on graphite and a layer of catecholamine coated with the nanoparticles, wherein the catecholamine coating layer provides a graphite composite formed from the catecholamine coating composition described above.

The present invention also provides a graphite-polymer composite in which the above-described graphite composite is dispersed in a polymer matrix.

According to the catecholamine coating composition of the present invention, the aggregation of the catecholamine-based compound particles is minimized and dispersed evenly in the polymer matrix, and the binding force with the polymer matrix having the minority / non-polarity chemical property is improved to enlarge the selection range of the polymer matrix . In addition, when the catecholamine coating composition according to the present invention is coated on a graphite composite, contact resistance in the vertical direction of the graphite can be prevented, and excellent electrical and thermal properties inherent to graphite can be efficiently utilized, .

1 is a perspective view illustrating a graphite composite according to an embodiment of the present invention, and
2 is a cross-sectional view taken along the line X-X 'in Fig.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings, which will be readily apparent to those skilled in the art to which the present invention pertains. The present invention may be embodied in many different forms and is not limited to the embodiments described herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and the same reference numerals are assigned to the same or similar components throughout the specification.

The catecholamine coating composition according to the present invention is embodied by including catecholamines and an oxidizing agent.

The term "catecholamine" refers to an ortho-group of a benzene ring, which means a single molecule having a hydroxy group (-OH) and various alkylamines in a para-group. The term "catecholamine" Various derivatives include dopamine, dopamine-quinone, alpha-methyldopamine, norepinephrine, epinephrine, alphamethyldopa, droxidopa, ), Indolamine, serotonin or 5-hydroxydopamine may be included in the catecholamine, and preferably dopamine may be used.

The dopamine is one of the neurotransmitters secreted from the nerve endings. Half of the neurohormones produced in the human brain are so important that they are related to dopamine. The dopamine is a monomolecular molecule composed of catechol Functional surface modification technique using dopamine was announced in 2007.

 The dopamine is a monomolecular substance having a molecular weight of 153 (Da) having catechol and amine functional groups. When a substance to be surface-modified is put into an aqueous solution of dopamine at a basic pH condition (about pH 8.5) It is known that dopamine is self-polymerized on the surface of a material to form a polydopamine (pDA) coating layer as shown in Formula 1 below.

[Chemical Formula 1]

At least one of R ₁ , R ₂ , R ₃ , R ₄ and R ₅ in Formula 1 is a thiol, a primary amine, a secondary amine, a nitrile, an aldehyde Imidazole, azide, halide, polyhexamethylene dithiocarbonate, hydroxyl, carboxylic acid, carboxylic acid, and the like. ester or carboxamide, and the remaining R ₁ , R ₂ , R ₃ , R ₄ and R ₅ are hydrogen.

On the other hand, with respect to the application of graphite, the reduction of chemical reactivity in the basal plane has been considered a major problem. On the surface of the graphite, there is no bonding part capable of chemical reaction, and since the bonding part exists at the edge of the graphite, the graphite surface is less chemically reactive than the edge. For this reason, generally, when pure graphite is to be dispersed in the polymer matrix, it is difficult to form a strong interfacial bond with the polymer matrix, so that it is not well dispersed.

In order to solve such a problem, Japanese Unexamined Patent Publication (Kokai) No. 10-2015-0110058 discloses a method of coating a nano-metal-crystallized graphite with catecholamine such as polydodamine to improve the bonding property with the polymer without deteriorating the inherent physical properties of the graphite itself A graphite composite having an increased dispersibility in a polymer matrix was prepared, thereby realizing a composite material having improved dispersibility in a polymer matrix.

However, the graphite composites disclosed in the above-mentioned patent publications show improved dispersibility in the polymer matrix. However, due to the following problems depending on the content of catecholamine, there are restrictions on application as new materials in various industrial fields.

First, when the content of the catecholamine compound is disclosed in the above-mentioned patents and the coating layer is formed on the graphite composite and dispersed in the polymer matrix, aggregation due to the bond between adjacent graphite composites occurs due to the excessive amount of the catecholamines So that each of the graphite composites may not be uniformly dispersed in the polymer matrix.

Second, typical catecholamine compounds show hydrophilic / polar chemical properties due to their NH and OH groups. When the content of the catecholamines is excessive, the polymer matrix due to such hydrophilic / polar properties Bonding power degradation may occur. For example, when the catecholamine layer is formed at a certain level or more, the hydrophilic / polar properties of the catecholamine layer are greatly increased, and the chemical bonding force is remarkably decreased by the chemical repulsion between the polymer matrix and the polymer matrix showing the minority / The adhesion with the matrix may be deteriorated. That is, since the polymer matrix exhibiting minor / non-polar chemical characteristics can not be selected depending on the content of catecholamines, application to various industrial fields is limited.

Thirdly, generally used graphite is in the form of a plate, which has superior electrical and thermal properties in the horizontal direction due to its structural properties, while electrical and thermal properties in the vertical direction between the layers are relatively low Level. At this time, when the catecholamine layer is excessively formed between the graphite layer and the layer, the contact resistance in the vertical direction is generated, which may hinder the utilization of excellent properties inherent to the graphite. That is, when the catecholamine layer thickness is increased due to the increase of the catecholamine content, the characteristics between the graphite layer and the graphite layer are remarkably deteriorated, which may result in poor applicability in fields requiring excellent electrical characteristics such as the electronics industry and the energy industry have.

Accordingly, the catecholamine coating composition according to the present invention is coated on a graphite composite so that a catecholamine compound forming the catecholamine layer is contained in an amount of 0.1 to 6 mM, thereby solving the above-mentioned problems and exhibiting excellent dispersibility in a polymeric material A graphite composite can be produced.

The content of the catecholamine compound may be in the range of 0.4 to 3 mM, more preferably, in order to prevent aggregation or agglomeration of the graphite complex. If the content of the catecholamine compound is less than 0.1 mM, The content of the compound is insufficient, the uniformity of the catecholamine layer covering the nanoparticles is lowered, and the bonding property with the polymer matrix may be deteriorated. If the content of the catecholamine compound exceeds 6 mM, the graphite composite may not be uniformly dispersed in the polymer matrix due to aggregation or agglomeration between the graphite complexes, and excessive thickness of the catecholamine layer having hydrophilic properties The selectivity of the polymer matrix having a small number of properties is deteriorated and the utilization of the polymer matrix in various industrial fields may be lowered.

Next, the catecholamine coating composition according to the present invention can greatly increase the polymerization rate of the catecholamine-based compound by including an oxidizing agent.

In general, the catecholamines require a coating time of more than 12 hours, and such a long-time coating process may hinder commercial applications. Accordingly, the present invention provides a catecholamine coating composition containing an oxidizing agent as a catalyst for solving the above-mentioned problems, and further relates to a catecholamine-based compound by adjusting the pH and the concentration of dopamine and controlling the mixing ratio of the oxidizing agent and the catecholamine compound Or to coat the catecholamine layer with a desired thickness.

The oxidizing agent is iron (Fe ^{+ 3),} chromium (Cr ^{+ 6),} manganese (Mn ^{+ 7),} iodine (I ⁷⁺⁾ a metal selected from the group above, with hydrogen peroxide or Na ₂ S ₂ O ₈ consisting of And the oxidizing agent may be used alone, or at least two kinds or more may be mixed and used. The oxidizing agent may preferably be sodium periodate, but any known oxidizing agent may be used without increasing the polymerization rate of the catecholamine compound and without affecting the physical properties of the catecholamine compound and the catecholamine layer.

The oxidizing agent may be mixed in an amount of 5 to 20 parts by weight, preferably 8 to 12 parts by weight, based on 100 parts by weight of the catecholamine compound. If the oxidizing agent is mixed below 5 parts by weight, the polymerization rate of the catecholamines is not improved as much as desired, and if the oxidizing agent is mixed in excess of 20 parts by weight, the content of the catecholamines is relatively reduced to decrease the content of the catecholamine coating composition The coating is not easy, and the bonding strength with the polymer matrix may be deteriorated.

The catecholamine coating composition for preparing the graphite composite may further comprise a solvent. The solvent may be used without limitation in the case of the catecholamine-based compound, the oxidizing agent, and the solvent having no physical / chemical influence. DI water).

On the other hand, the solvent may be a mixed solution containing an organic solvent in addition to water in order to improve the hydrophilicity of the graphite and / or nanoparticle surface. Since the catecholamine coating composition according to the present invention contains a low concentration catecholamine compound as compared with the above-mentioned patent, it is possible to minimize the excessive formation of the catecholamine layer in the graphite composite. However, if the catecholamine coating layer is formed on the graphite and / Can be made difficult to form properly. Preferably, the catecholamine layer can be formed using the graphite on which the nanoparticles hydrophilized through the organic solvent are formed, thereby facilitating proper formation of the catecholamine layer on the graphite and / or nanoparticles , Whereby there is the advantage that a separate hydrophilic modification can be omitted for the graphite and / or the graphite in which the nanoparticles are formed before the treatment of the coating composition.

The organic solvent may be uniformly coated on the surface of the hydrophobic graphite composite such as alcohol, acetonitrile, 1,4-dioxane, acetone, DMF, DMSO and NMP without forming droplets due to cohesive force. Can be used without limitation in the case of known organic solvents which can be dissolved well. Preferably, methanol, which is an alcohol that spreads entirely without forming droplets due to cohesive force even on a hydrophobic surface, can be used. At this time, the methanol may be mixed with the mixed solution in a volume of 1: 1 to 1: 5.

The catecholamine coating composition described above can be coated by a coating method described below, but is not limited thereto.

The catecholamine coating composition according to the present invention is coated including (1) preparing the catecholamine coating composition described above and (2) polymerizing the catecholamine coating composition to form a catecholamine layer on the graphite composite.

First, the step (1) is a step of preparing a catecholamine coating composition. Wherein the coating composition comprises a catecholamine-based compound, wherein the catecholamine-based compound is an ortho-group of benzene rings, a monomolecule having a hydroxy group (-OH) and a variety of alkylamines in a para- The term is used to describe various derivatives of such structures, including dopamine, dopamine-quinone, alpha-methyldopamine, norepinephrine, epinephrine, alpha-methyldopa alpha-methyldopa, droxidopa, indolamine, serotonin or 5-hydroxydopamine may be included in the catecholamine, and preferably dopamine may be used .

The catecholamine compound may be dissolved in a buffer and mixed with an oxidizing agent to prepare a mixed solution. The oxidizing agent may be used alone or in combination of at least two kinds of iron (Fe ^{3 +} ), chromium (Cr ^{6 +),} manganese (Mn may be ^{7 +),} iodine (I ⁷⁺⁾ a metal selected from the group above, with hydrogen peroxide or Na ₂ S ₂ O ₈ made.

According to an example, when the catecholamine compound is dopamine, the oxidizing agent of the mixed solution may be mixed in an amount of 5 to 20 parts by weight based on 100 parts by weight of the dopamine. If the oxidizing agent is mixed below 5 parts by weight, the polymerization rate of the catecholamines is not improved as much as desired, and if the oxidizing agent is mixed in excess of 20 parts by weight, the content of the catecholamines is relatively reduced to decrease the content of the catecholamine coating composition The coating is not easy, and the bonding strength with the polymer matrix may be deteriorated.

The next step (2) is a step of forming a catecholamine layer on the graphite composite through the catecholamine coating composition.

In the step (2), a known general coating method may be used, but an immersion coating process or a spray coating process may be used.

As an example of the coating process, when an immersion coating process is used, an appropriate amount of graphite to be coated is mixed with 0.1 to 6 mmol of a catecholamine compound and an oxidizer dissolved therein, and the mixture is stirred at room temperature for 1 to 4 hours have. Thereafter, unreacted materials are removed by filtration, washed with Di-water, and then dried at room temperature to obtain a graphite composite having a catecholamine layer.

As another example of the coating process, when a spray process is used, a catecholamine compound and an oxidant, which are separated from each other, are mixed in a single line and sprayed onto the surface of a graphite composite to be coated, Can be designed. At this time, the catecholamine compound and the oxidizing agent can be simultaneously introduced into one line from each of the separated lines by the pressure difference applied by the spray, and then mixed (in-line mixing). And then sprayed onto the substrate surface through a spray outlet to coat the catecholamine coating composition for making the graphite composite.

At this time, the step (1) and the step (2) may further include modifying the surface of the graphite composite to be hydrophilic by using oxygen plasma.

In the step of modifying the hydrophilic property, the surface of the graphite composite is temporarily hydrophilized so as to uniformly coat the catecholamine coating composition on the surface of the graphite composite having hydrophobicity, and then the mixed solution is sprayed using the spray coating process described above Coating method. If the hydrophobic graphite composite surface is subjected to a coating process without the hydrophilization step, the composition becomes cloudy due to the hydrophobic property of the graphite surface, and the catecholamine coating composition for preparing the graphite composite is coated only on the unified portion A problem that a uniform coating can not be obtained as a whole may occur. Therefore, the present invention can further include the hydrophilization step, so that the catecholamine coating composition for preparing a hydrophilic graphite composite can be uniformly and uniformly coated on the surface of the base material graphite composite having hydrophobicity.

1 and 2, the graphite composite 100 according to an exemplary embodiment of the present invention includes a catecholamine layer 30 formed by coating a catecholamine coating composition including nanoparticles 20 on a graphite 10 Respectively. The graphite composite 100 may further include a polymer layer 40 formed on the catecholine layer 30.

The catecholamine layer 30 capable of improving the dispersibility of the graphite 10 in the heterogeneous material is provided on the surface of the graphite 10 because the surface of the graphite 10 is free of functional groups capable of mediating the chemical reaction It is not easy to give. Accordingly, even when the catecholamine is treated to the graphite 10, the amount of the catecholamine remaining in the graphite 10 is very small. Further, in order to solve this problem, there is a limitation in increasing the amount of catecholamine on the surface of the modified graphite even if the modifying treatment for imparting a functional group to the surface of the graphite 10 is performed. However, in the case of the graphite 10 in which the nanoparticles 20 are provided on the surface, there is an advantage that the catecholamine can be introduced into the graphite by the desired amount as the catecholamine is easily bonded onto the surface of the nanoparticle.

The graphite 10 which can be used in the present invention can be obtained through various methods known in the art. For example, a thermosetting resin such as polyimide is formed into a film having a thickness of 25 占 퐉 or less and graphitized at a high temperature of 2500 占 폚 or higher to produce a monocrystalline graphite 10, or a hydrocarbon such as methane is pyrolyzed at a high temperature, There is a method of obtaining a highly oriented graphite 10 by CVD (Chemical Vapor Deposition)

The nanoparticles 20 used in the present invention may be a metal or a nonmetal substance existing in a solid state at room temperature. For example, the nanoparticles 20 may be an alkali metal, an alkaline earth metal, a lanthanum group, an actinide group, Metals, semi-metals, and the like. Preferably, the metal material is an alkali metal, an alkaline earth metal, a lanthanum group, an actinium group, or a transition metal. For example, the nanoparticles 20 may be selected from Ni, Si, Ti, Cr, Mn, Fe, Co, Cu, Sn, In, Pt, Au, Mg, Is more preferable.

The nanoparticles 20 may have an average particle diameter of 10 to 500 nm, preferably 10 to 100 nm. In addition, the nanoparticles 20 may be provided in an amount of 10 to 70% area, more preferably 30 to 70% of the entire surface area of the individual graphite 10, have. The nanoparticles 20 may be present in an amount of 5 to 70% by weight, preferably 20 to 50% by weight based on the total weight of the graphite composite 100. At this time, the nanoparticles 20 are chemically bonded to the graphite 10 to exhibit stronger binding force.

The polymer constituting the polymer layer 40 may be selected from the group consisting of a thermosetting resin, a thermoplastic resin, and a rubber, though the kind of the polymer is not particularly limited. The thermosetting resin is not particularly limited in its kind Based resin, an epoxy-based resin, an urethane-based resin, an ester-based resin, a polyimide-based resin, and mixtures thereof. The thermoplastic resin is not particularly limited as long as it is a polycarbonate, polystyrene, polysulfone, Based resin, a polyether-based resin, a polyether-based resin, a polyether-based resin, a polyacrylate resin, a polyester resin, a polyamide resin, a cellulose resin, a polyolefin resin, a polypropylene resin, a polyketone resin, The rubber includes all of rubber elastomers including natural rubber and the like.

Since the surface of the graphite composite 100 forms the polymer layer 40, not only the low dispersibility and aggregation phenomenon of the graphite itself, but also the aggregation due to the high adhesive property of the catecholamine layer 30 itself does not occur, Since the dispersion is uniform, it can be usefully used to make a composite having excellent electrical and thermal properties.

In addition, the present invention implements a graphite-polymer composite material by dispersing the graphite composite 100 including the catecholamine layer 30 in a polymer matrix.

At this time, if the polymer used for the polymer layer 40 and the polymer used for the polymer matrix have mutual reactivity and coordination with each other, there is no particular limitation on their kind, but preferably, the kind of the polymer matrix used for the composite material, It is preferable that the kinds of the polymers forming the polymer layer 40 of the invention are the same. Most preferably, the same type of polymer is used. For a detailed description of the polymer, reference may be had to the description given above.

Since the graphite composite 100 is extremely uniformly dispersed in the composite, the excellent characteristics of the graphite can be utilized as it is.

Generally, since the graphite 10 has a charge mobility of about 200,000 cm ² / V at room temperature, the graphite 10 uniformly dispersed in the polymer matrix exhibits a high electric conductivity by bonding with the polymer matrix to have a high current density . In addition, when the composite material is produced by dispersing graphite (10) in an insulating polymer matrix in addition to a conductive polymer matrix, the dispersed graphite (10) forms a conductive channel through which electrons can move so that the graphite- Conduct conductivity. Further, since the graphite 10 exhibits excellent mechanical properties, it is not necessary to increase the thickness of the composite molded article in order to have a desired mechanical property value when the graphite 10 is added to the polymer matrix, Light weight can be made possible and can be utilized for an ultra light / high strength material application. Further, the graphite 10 has a thermally highly stable structure with a stable double bond between carbon atoms, and when added to a polymer matrix, the glass transition temperature (Tg) and decomposition temperature of the graphite-polymer composite material can be improved with only a small amount . In addition, since the composite material based on the graphite 10 is filled in the polymer matrix due to the high thermal conductivity (5000 W / (mK)) of the graphite 10, the thermal conductivity of the composite material can be greatly improved .

The graphite has a coefficient of thermal expansion of -1.5 × 10 ^-6 / ° C. at room temperature and a coefficient of thermal expansion of 2.7 × 10 ^-5 / ° C. in the axial direction. Since such a thermal expansion coefficient value is very low as compared with that of a pure polymer, when the graphite composite is dispersed in a polymer resin to make a composite material, the composite material produced by relaxing the phenomenon that the polymer resin rapidly expands has dimensional stability . This is a very important consideration in the production of polymer molded articles. Especially, in the process of cooling the molded product after the polymer is melted and injected into the mold, a rapid shrinkage phenomenon is prevented, and a polymer molded article having uniform dimensions can be produced.

The graphite-polymer composite material including the graphite can be used in various industrial fields such as electronic device parts, energy storage media, organic solar cells, heat radiation materials, film packaging materials and biomimetic application devices.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (9)

A catecholamine coating composition for forming the catecholamine layer on a graphite composite comprising nanoparticles formed on graphite and a layer of catecholamine coated with nanoparticles,
A catechol amine compound and an oxidizing agent,
Wherein the catecholamine compound is contained in an amount of 0.1 to 6 mM. The method according to claim 1,
The catecholamine compound may be selected from the group consisting of dopamine, dopamine-quinone, alpha-methyldopamine, norepinephrine, epinephrine, alphamethyldopa, A catecholamine coating composition selected from the group consisting of droxidopa, indole amines, serotonin and 5-hydroxydopamine. The method according to claim 1,
The oxidizing agent is iron (Fe ^{+ 3),} chromium (Cr ^{+ 6),} manganese (Mn ^{+ 7),} iodine (I ⁷⁺⁾ a metal selected from the group consisting in hydrogen peroxide, or Na ₂ S ₂ O ₈ any one of the Lt; / RTI > The method according to claim 1,
Wherein the catecholamine coating composition further comprises an organic solvent,
The organic solvent is selected from the group consisting of alcohols, acetonitrile, 1,4-dioxane, acetone, dimethylformamide (DMF), dimethylsulfoxide (DMSO) NMP). ≪ / RTI > The method according to claim 1,
Wherein the oxidizing agent is mixed in an amount of 5 to 20 parts by weight based on 100 parts by weight of the catecholamine compound. (1) preparing a catecholamine coating composition according to any one of claims 1 to 5; And
(2) forming a catecholamine layer on the graphite composite through the catecholamine coating composition. 7. The method of claim 6, further comprising, between steps (1) and (2)
A method of coating a catecholamine coating composition, which further comprises modifying the graphite composite surface to hydrophilicity using oxygen plasma. A graphite composite comprising nanoparticles formed on graphite and a layer of catecholamine coated with nanoparticles,
Wherein the catecholamine layer is formed from the catecholamine composition according to any one of claims 1 to 5. A graphite-polymer composite according to claim 8, wherein the graphite composite is dispersed in a polymer matrix.

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