WO2015182829A1 - Graphene-polymer composite and method for preparing same - Google Patents

Graphene-polymer composite and method for preparing same Download PDF

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WO2015182829A1
WO2015182829A1 PCT/KR2014/008595 KR2014008595W WO2015182829A1 WO 2015182829 A1 WO2015182829 A1 WO 2015182829A1 KR 2014008595 W KR2014008595 W KR 2014008595W WO 2015182829 A1 WO2015182829 A1 WO 2015182829A1
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graphene
polymer composite
amphoteric
polymer
methacrylate
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French (fr)
Korean (ko)
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정한모
다오트렁덩
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울산대학교 산학협력단
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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
    • C08J5/005—Reinforced macromolecular compounds with nanosized materials, e.g. nanoparticles, nanofibres, nanotubes, nanowires, nanorods or nanolayered materials
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/02—Elements
    • C08K3/04—Carbon
    • C08K3/042—Graphene or derivatives, e.g. graphene oxides
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J3/00—Processes of treating or compounding macromolecular substances
    • C08J3/12—Powdering or granulating
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J3/00—Processes of treating or compounding macromolecular substances
    • C08J3/20—Compounding polymers with additives, e.g. colouring

Definitions

  • the present invention relates to a graphene-polymer composite and a method for preparing the same, specifically, a polymer core; And it consists of a shell containing the amphoteric graphene relates to a graphene-polymer composite excellent in electrical conductivity and a method for producing the same.
  • Graphene is a new nanomaterial having excellent physical properties, and researches for applying it in various fields have been actively conducted in recent years. Specifically, graphene has excellent properties such as a modulus of 1 TPa, an electrical conductivity of 10 6 S / cm, a thermal conductivity of 5000 W / m ⁇ K, and a large surface area of 2600 m 2 / g. The potential is excellent.
  • graphene is known to be a material that cannot exist independently. Only theoretical studies have been carried out, but since the Geim Group at the University of Manchester in 2004 confirmed the existence of graphene, graphene is a new conductive nanomaterial. In the spotlight, various studies are being conducted worldwide.
  • composites prepared by mixing graphene with a polymer have been developed in order to use the excellent physical properties of graphene.
  • the composite is not only a variety of physical properties by the graphene, but also to attract the attention as a new material because it can maximize the desired physical properties by appropriately adjusting the structure according to the use.
  • dispersing graphene in a polymer matrix to maximize the interface area between graphene and the polymer, thereby improving the interaction between the graphene and the polymer at the interface can be achieved by optimization.
  • Korean Patent Publication No. 2013-0125388 proposes a composite having a structure in which graphene oxide is dispersed in a polymer matrix using graphene oxide or graphite oxide including a plurality of functional groups on its surface as a catalyst for polymerization. .
  • Korean Patent Laid-Open Publication No. 2010-0109258 proposes an electrically conductive particle coated with graphene by polymer binding the polymer fine particles modified with an ionic functional group and the graphene modified with an ionic functional group on the surface. .
  • Graphene Attached on Microsphere Surface for Thermally Conductive Composite Material Jae-Yong Choi, et.al., Clean Technology, Vol. 19, No. 3, 243
  • a technique for preparing polymethyl methacrylate microparticles having graphene distribution on the surface by using a graphene solution having an interfacial stabilizer introduced through a water dispersion as a water phase is proposed.
  • the structure in which graphene is dispersed in the polymer matrix in terms of electrical conductivity is inferior in physical properties to the composite of the graphene-coated structure, and graphene oxide is also compared with the reduced graphene.
  • when modifying to have a hydrophilicity on the graphene surface in order to improve the dispersibility of the graphene it is accompanied by a modification of the graphene inherent delocalized carbon-carbon double bond to add a separate reaction point, thereby Intrinsic physical properties may be reduced, resulting in insignificant physical properties of the polymer composite.
  • the interfacial stabilizer or dispersion stabilizer there is a problem that the physical properties implemented by the graphene may be reduced by remaining on the surface of the finally prepared polymer composite.
  • An object of the present invention is to provide a graphene-polymer composite having excellent electrical conductivity since the physical properties of graphene are not degraded.
  • Another object of the present invention is to provide a method for producing the graphene-polymer composite that is performed without the use of a stabilizer to improve the dispersibility of graphene.
  • amphoteric graphene provides a graphene-polymer composite including n hydrophilic groups satisfying Equation 1 for 100 graphene carbon atoms:
  • It provides a graphene-polymer composite manufacturing method for producing a graphene-polymer composite by performing a polymerization reaction of a mixture containing a vinyl monomer, an initiator and amphoteric graphene.
  • the graphene-polymer composite according to the present invention has a structure in which a polymer, which is a core, is coated with amphoteric graphene having 0.2 ⁇ n ⁇ 60 hydrophilic groups introduced on its surface with respect to 100 graphene carbon atoms, thereby inherent in graphene. There is no deterioration and excellent electrical conductivity is realized even when a small amount of graphene is contained, and thus may be usefully used in various fields requiring electrical conductivity.
  • Figure 2 is a scanning electron microscope (SEM) analysis of the graphene-polymer composite prepared in one embodiment according to the present invention: (a) is an image of 150 magnification, (b) is a 3,000 magnification Image.
  • SEM scanning electron microscope
  • the terms "comprises” or “having” are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, and one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, components, or a combination thereof.
  • “phr” refers to the content of amphoteric graphene (Parts per Hundred Resin) used per 100 parts by weight based on the core polymer or the monomer used in the polymerization reaction.
  • stabilizer refers to an additive in which a monomer or polymer used for polymerization is stably maintained in the shape of droplets or fine particles in a polymerization reaction performed with water as a dispersion medium.
  • the stabilizer may include, for example, an emulsifier or a surfactant used in an emulsion polymerization reaction to stably form an emulsion of a reaction solvent and an organic monomer; Dispersants used in the suspension polymerization reaction to stably form droplets of organic monomers in the reaction solvent; Or particle stabilizers used in the dispersion polymerization reaction in order to prevent the fine particles formed by polymerization from agglomerating in the dispersion medium.
  • bilateral means hydrophilicity and hydrophobicity in one molecule or one particle; Or it means showing both hydrophilicity and lipophilic at the same time.
  • bilateral graphene refers to graphene in which both hydrophobicity and hydrophilicity are implemented by imparting hydrophilicity by introducing COO - or SO 3 - to hydrophobic graphene.
  • the present invention relates to a graphene-polymer composite and a preparation method thereof.
  • Graphene is a material that has recently attracted attention in various fields because of its excellent physical properties.
  • the graphite-based materials are not dispersed well in the polymer and are aggregated so that the desired physical properties are not effectively realized.
  • many studies have been conducted to improve this.
  • techniques for improving the dispersibility of water by improving the surface of graphene or controlling the dispersion of graphene using a stabilizer have been published.
  • a separate reaction point is required on the surface, a deformation of carbon-carbon double bonds delocalized on the surface of graphene is accompanied, and when stabilizers are used, stabilizers remain in the finally prepared composite. Since there is a problem that the inherent physical properties of the graphene is implemented in the composite.
  • the present invention proposes a graphene-polymer composite having excellent electrical conductivity and a method of manufacturing the same by minimizing the degradation of inherent properties of graphene.
  • graphene having 0.2 ⁇ n ⁇ 60 hydrophilic groups introduced to the surface of 100 graphene carbon atoms in the preparation of the graphene-polymer composite graphene is not used without using an interfacial stabilizer, dispersion stabilizer, or the like.
  • the invention in one embodiment, a polymer core
  • amphoteric graphene provides a graphene-polymer composite including n hydrophilic groups satisfying Equation 1 for 100 graphene carbon atoms:
  • the graphene-polymer composite may include a shell composed of a polymer core and amphoteric graphene coating the same.
  • the graphene forming the shell may be a hydrophilic group introduced into the surface having an amphoteric.
  • Conventionally performed techniques for introducing a hydrophilic group on the graphene surface deforms the unlocalized carbon-carbon double bond on the graphene surface, thereby degrading the inherent physical properties of the graphene.
  • the amphoteric graphene used in the present invention does not modify carbon-carbon double bonds unlocalized on the graphene surface, and uses reactive groups remaining on the graphene surface, specifically, epoxy groups remaining on the graphene surface.
  • hydrophilic groups may be introduced for 100 graphene carbon atoms. More specifically 0.2 to 40; 0.2 to 30; Or 0.2 to 20 hydrophilic groups may be introduced.
  • the introduction amount of the hydrophilic group can maintain the inherent physical properties of graphene by preventing deformation of the unlocalized carbon-carbon double bond on the graphene surface within the above range, the hydrophilicity imparted to the graphene surface and the hydrophobicity of graphene itself The ratio can be effectively controlled to have amphotericity.
  • the hydrophilic group according to the present invention is not particularly limited as long as it is a substituent capable of inducing hydrophilicity on the surface of graphene, specifically, may include any one or more of COO - M + and SO 3 - M + .
  • M is H; Alkali metals such as Li, Na, K, Rb and Cs; Or quaternary amines.
  • the content of graphene constituting the shell is not particularly limited as long as it is an amount capable of improving the electrical conductivity while stabilizing the water dispersion of the polymer particles as the core. May be 0.1 to 10 phr relative to the polymer core. More specifically 0.1 to 8 phr; 0.2 to 6 phr; Or 0.3 to 5 phr.
  • Equation 2 In evaluating the electrical conductivity (L), the following Equation 2 may be satisfied:
  • the unit of the electrical conductivity (L) is S / cm.
  • the electrical conductivity of the graphene-polymer composite according to the present invention with an amphoteric graphene content of 0.3 to 5.0 phr relative to the polymer core was evaluated.
  • the electrical conductivity was found to be 8.43 X 10 -4 S / cm.
  • the electrical conductivity of the pure polymethyl methacrylate used as the core is 1.75 X 10 -12 S / cm, the electrical conductivity is significantly lower, whereas the graphene-polymer composite according to the present invention is depending on the content of the amphoteric graphene 5.39 X 10 -5 to 1.57 X 10 -1 S / cm, the electrical conductivity of 3.1 X 10 7 to 9.0 X 10 10 times better than that of pure polymethylmethacrylate.
  • Experimental Example 2 shows that shows that of pure polymethylmethacrylate.
  • the graphene-polymer composite according to the present invention can implement excellent electrical conductivity even when the amphoteric graphene is contained in a small amount of 0.1 to 10.0 phr relative to the polymer core, the content of the amphoteric graphene in the polymer core
  • About 1 phr of graphene-polymeric electrical conductivity of the complex is 1.0 ⁇ 10 -8 S / cm or more, specifically 1.0 ⁇ 10 -5 S / cm or higher, more specifically from 1.0 ⁇ 10 -4 S / cm or more, or It turns out that it is 4.0 * 10 ⁇ -4> S / cm or more.
  • the polymer core according to the present invention is not particularly limited in kind, specifically, for example, methyl acrylate (methylacrylate, MA), ethyl acrylate (ethylacrylate, EA), butyl acrylate (butylacrylate, BA), methyl methacrylate (MMA), ethyl methacrylate (EMA), butyl methacrylate (BMA), 2-ethylhexyl methacrylate (EHMA), glycy Glycidyl methacrylate (GMA), styrene, alpha-methylstyrene, vinyl chloride, vinylidene chloride, ethylene, propylene, etc. It may be a polymer polymerized using at least one vinyl monomer of.
  • the graphene-polymer composite according to the present invention includes an amphoteric graphene having 0.2 ⁇ n ⁇ 60 hydrophilic groups introduced on its surface with respect to 100 graphene carbon atoms, and thus has excellent electrical conductivity. It can be used as a good electrical conductivity.
  • a method for preparing a graphene-polymer composite to prepare a graphene-polymer composite by carrying out a polymerization reaction of a mixture including a vinyl monomer, an initiator and amphoteric graphene.
  • MMA methyl methacrylate
  • AIBN 2,2-azobisisobutyronitrile
  • amphoteric graphene can be mixed in. Thereafter, the mixture may be polymerized at 55 to 85 ° C., the powder formed by the polymerization may be filtered and washed, and then dried to prepare a graphene-polymer composite according to the present invention.
  • the polymerization reaction according to the present invention may be dispersion polymerization, emulsion polymerization or suspension polymerization.
  • the amphoteric graphene has a suitable ratio of hydrophilicity and hydrophobicity (the same as lipophilic) so that the hydrophobic monomer can be stably present in fine particles or droplets in water used as a reaction solvent of a polymerization reaction. Serves as a "Pickering Stabilizer".
  • the “Pickering Stabilizer” refers to micro or nanometer-sized solid particles dispersed in a mixture of two liquids (eg, water and oil) that are different in polarity and do not mix with each other. Solid particles have the function of physically stabilizing to prevent coalescence of emulsion particles. That is, the amphoteric graphene according to the present invention can be stabilized so that the monomer can be formed and polymerized by being located at the interface between the monomer and the water of the dispersion medium in the polymerization reaction of the polymer as the core.
  • the method for preparing the graphene-polymer composite according to the present invention can be performed without using a separate stabilizer by using amphoteric graphene, and therefore, there is no remaining stabilizer in the conventional dispersion polymerization, emulsion polymerization or suspension polymerization. Therefore, it is possible to minimize the deterioration of the physical properties of graphene.
  • the graphene-polymer composite thus prepared may have a structure in which the amphoteric graphene forms a shell by using the polymerized polymer as a core, and some of the amphoteric graphene is polymerized. Alternatively, or depending on the degree of hydrophobicity of the amphoteric graphene, it may be present in the composite together with the polymer that is the core.
  • amphoteric graphene according to the invention may be surface modified with a compound containing a hydrophilic group.
  • the amphoteric graphene may be obtained by oxidizing a commercially available graphite powder, reducing it again to prepare graphene, and then surface modifying the prepared graphene with a compound containing a hydrophilic group.
  • the amphoteric graphene according to the present invention can utilize a functional group containing oxygen remaining in the reduced graphene, that is, an epoxy group, so that when modified, it is inherent to graphene without deformation of the carbon-carbon double bonds delocalized on the graphene surface. Physical property degradation can be minimized and the degree of hydrophilicity and hydrophobicity can be controlled appropriately.
  • the method for oxidizing the graphite powder is, for example, NaClO 3, KClO 3, KMnO 4, etc. can be used alone or in combination, or by electrochemical oxidation method for oxidizing agent.
  • the graphite oxide powder thus prepared may have an element ratio of carbon to oxygen of 1 to 20: 1, but is not limited thereto.
  • the graphite oxide powder has an interlayer distance of about 7 ⁇ s, the 2 ⁇ of the peak observed in the X-ray diffraction analysis may be about 13 ⁇ 1 °, and the error may vary depending on the degree of oxidation and moisture absorption of the graphite oxide powder. May occur.
  • the method of reducing the graphite oxide for example, a heat reduction method of reducing and swelling and peeling off the layers constituting the graphite oxide by heat treatment at a high temperature of 300 °C or more under an inert gas instantaneously;
  • a chemical reduction method may be used in which the graphite oxide is dispersed in a liquid medium and reduced with a reducing agent such as hydrazine, but is not limited thereto.
  • amphoteric graphene according to the present invention is a graphene prepared by reducing the graphite oxide
  • M of the hydrophilic group can be prepared by modifying with a compound containing a hydrophilic group which is H, Li, Na, K, Rb, Cs or quaternary amine.
  • the hydrophobic graphene prepared by reducing graphite oxide may have an epoxy group on a surface thereof. Therefore, the surface of graphene is modified by reacting an epoxy group remaining on the graphene surface with a compound containing a hydrophilic group, a SO 3 ⁇ group and one amine group, for example, 2-aminoethanesulfonic acid, thereby modifying the surface of the graphene. Pins can be manufactured.
  • the hydrophilic group COO - or SO 3 - may perform a function of imparting hydrophilicity to the hydrophobic graphene.
  • the amine group of the compound containing a hydrophilic group may perform a function of reacting with the epoxy group remaining on the graphene surface to modify the surface of the graphene.
  • the compound having one amine group may be used.
  • amphoteric graphene according to the present invention may include n hydrophilic groups satisfying Equation 1 for 100 graphene carbon atoms:
  • the amphoteric graphene according to the present invention is 0.2 to 60, more specifically 0.2 to 40 with respect to 100 graphene carbon atoms; 0.2 to 30; Or 0.2 to 20 hydrophilic groups may be introduced.
  • the amphoteric graphene can efficiently control the hydrophilicity and lipophilicity of the modified graphene by introducing a hydrophilic group within the above range for 100 carbon atoms, and thus, during polymerization of the core polymer, (Pickering Stabilizer) ".
  • the mixing amount of the graphene (graphene) is particularly limited as long as it can stabilize the water dispersion and improve the electrical conductivity of the polymer particles polymerized to form the core.
  • it may be specifically 0.1 to 10 phr relative to the vinyl monomer. More specifically 0.1 to 8 phr; 0.2 to 6 phr; Or 0.3 to 5 phr.
  • the electrical conductivity of the graphene-polymer composite according to the present invention with an amphoteric graphene content of 0.3 to 5.0 phr relative to the polymer core was evaluated.
  • the electrical conductivity of pure polymethyl methacrylate used as the core the electrical conductivity is significantly low as 1.75 X 10 -12 S / cm
  • graphene in accordance with the present invention the polymer composite is 5.39 X 10 -5 to 1.57 Since it exhibits an electrical conductivity of X 10 ⁇ 1 S / cm, it can be confirmed that the electric conductivity is 3.1 X 10 7 to 9.0 X 10 10 times superior to that of pure polymethylmethacrylate (see Experimental Example 2).
  • the graphene-polymer composite according to the present invention realizes excellent electrical conductivity even when the amphoteric graphene contains a small amount of 0.1 to 10.0 phr with respect to the polymer core.
  • the size of the graphene-polymer composite prepared according to the method for producing the graphene-polymer composite according to the present invention may be 0.01 to 10,000 ⁇ m. Specifically, it may be 0.01 to 1000 ⁇ m, 0.1 to 500 ⁇ m, 0.1 to 250 ⁇ m or 1 to 250 ⁇ m.
  • the particle size of the graphene-polymer composite according to the invention was measured in which the amphoteric graphene content is 0.3 to 5.0 phr relative to the polymer core.
  • the particle size of the graphene-polymer composite according to the present invention is about 56.9 to 226.1 ⁇ m, and the graphene-polymer composite has a tendency to decrease the particle size of the prepared composite as the amount of amphoteric graphene increases It can confirm that (refer experimental example 1).
  • the vinyl monomer according to the present invention is not particularly limited in kind, but specifically, for example, methyl acrylate (methyl acrylate, MA), ethyl acrylate (ethyl acrylate, EA), butyl acrylate (butyl acrylate, BA) Methyl methacrylate (MMA), ethyl methacrylate (EMA), butyl methacrylate (BMA), 2-ethylhexyl methacrylate (EHMA), glycidyl methacrylate Glycidyl methacrylate (GMA), styrene, alpha-methylstyrene, vinyl chloride, vinylidene chloride, ethylene, propylene, etc. Can be.
  • graphite having an average particle size of 280 ⁇ m was expanded for 1 minute. Thereafter, the expanded graphite (10 g) was injected with fuming nitric acid (200 mL) into a 1000 mL reactor equipped with a stirrer and a thermometer, and stirred while maintaining 0 ° C. Potassium chlorate (85 g) was slowly added over 1 hour while stirring, and graphite was oxidized while stirring at room temperature for 24 hours. The oxidized graphite was filtered and washed with distilled water until the pH of the filtrate was 6. The washed graphite oxide was dried at 100 ° C. under vacuum for one day, and the dried graphite oxide was charged into a quartz tube.
  • Step 2 Preparation of Amphoteric Graphene Modified with Sulfonic Acid Group
  • 2-aminoethanesulfonic acid (20.0 g, 0.16 mol) and potassium hydroxide (KOH, 9.0 g, 0.16 mol) were dissolved in water (35 g) and stirred for 30 minutes.
  • graphene (1 g) prepared in step 1 was added to acetone (150 mL) and sonicated for 1 hour to disperse the graphene in acetone.
  • the graphene-dispersed dispersion and the 2-aminoethanesulfonic acid solution were mixed and stirred for 1 hour, the mixed solution was sonicated for 20 minutes, and then stirred at 60 ° C. for 2 days to surface the graphene in the solution. Modified.
  • the mixed solution was filtered to separate graphene, and the separated graphene was washed with acetone mixed with hot water. Thereafter, the mixture was dried under vacuum at 60 ° C. for 1 day to prepare amphoteric graphene modified with a sulfonic acid group which is a hydrophilic group.
  • well-modified amphiphilic average particle size of the pin is 8.4 ⁇ m, and the atom composition yiyeotda C 10 O 1.03 H 1.21 N 0.14 S 0.13.
  • a carboxyl group was modified in the same manner as in Preparation Example 1, except that 6-aminocaproic acid (21.0 g, 0.16 mol) was used instead of 2-aminoethanesulfonic acid in Step 2 of Preparation Example 1. Amphoteric graphene was prepared.
  • the graphene prepared in Preparation Example 1 was added to water (150 g) and sonicated for 1 hour to disperse the graphene, and then methyl methacrylate (MMA, 10 g) as a vinyl monomer and 2,2 as an initiator.
  • MMA methyl methacrylate
  • a solution containing azobisisobutyronitrile (AIBN, 0.15 g) was added to a dispersion in which graphene was dispersed, and stirred at a speed of 2000 rpm for 5 minutes. At this time, the mixed amount of graphene was mixed in 0.3 to 5.0 phr relative to the monomer, as shown in Table 1 below.
  • the temperature was raised to 70 ° C., and the suspension polymerization reaction was performed at 300 rpm for 1 day while maintaining the elevated temperature.
  • the mixed solution was filtered to separate the graphene-coated polymer powder, and the separated powder was dried at 90 ° C. for 1 day under vacuum to prepare a graphene-polymethylmethacrylate composite powder according to the present invention.
  • Example 1 Table 1 Graphene Blending Amount (phr) Example 1 0.3 Example 2 0.5 Example 3 1.0 Example 4 2.0 Example 5 3.0 Example 6 5.0
  • Graphene prepared in Preparation Example 1 was added to acetone (100 g), and sonicated for 1 hour to disperse the graphene. Then, a solution of polymethyl methacrylate (PMMA, 10 g) dissolved in acetone (250 g) was added to the dispersion, stirred and mixed, and then acetone was removed to remove the graphene-polymethyl methacrylate composite powder. Prepared. At this time, as shown in Table 2, the mixed amount of graphene was mixed at 0.0 to 5.0 phr with respect to the vinyl monomer.
  • PMMA polymethyl methacrylate
  • the graphene-polymer composite according to the present invention has a particle form of a shell formed by coating polymethyl methacrylate, which is an amphoteric graphene core, without using a separate stabilizer It can be seen that it is stably produced by the suspension polymerization reaction.
  • FIG. 2 is a scanning electron microscope analysis of the graphene-polymethyl methacrylate complex prepared in Example 5 at 150 magnification, the complex is a rough surface of the spherical It can be confirmed that it is a particle.
  • (b) of FIG. 2 is a 20 times magnification (3,000 magnification) of (a), wherein the modified amphoteric graphene is coated with polymethylmethacrylate to form a shell, and (b) It can be confirmed that it has a form in which some peeled off as indicated in the figure.
  • Example 1 86.4 226.1
  • Example 2 90.8 168.1
  • Example 3 94.4 165.6
  • Example 4 87.4 129.9
  • Example 5 96.6 107.8
  • Example 6 93.8 56.9
  • the polymerization reaction is carried out in an excellent yield of about 85% or more irrespective of the mixed amount of the amphoteric graphene added, the particle size is It can be seen that the polymerization decreases with increasing amount of the amphoteric graphene mixed with methyl methacrylate. This coincides with the reaction tendency of dispersion polymerization, emulsion polymerization or suspension polymerization in which the particle size of the prepared polymer decreases as the amount of dispersion stabilizer increases.
  • the modified amphoteric graphene coats a polymer to form a shell and at the same time plays a role of "pickering stabilizer" in the polymerization reaction.
  • the production method of the graphene-polymer composite according to the present invention by using a composite using a modified amphoteric graphene, it is possible to perform a polymerization reaction stably without using a separate stabilizer, so It can be seen that the composite prepared has the form of polymer particles forming a shell by coating the amphoteric graphene modified on the surface.
  • Example 1 Graphene-polymethyl methacrylate composite particles prepared in Example 1 according to the present invention by compression molding under a pressure condition of 130 °C, 10 MPa to prepare a specimen in the form of a sheet (3.0 cm 3.0 cm ⁇ 100 ⁇ m) It was.
  • the graphene-polymethyl methacrylate composite particles prepared in Examples 2 to 6, and Comparative Examples 1 to 7 were compression molded in the same manner as above to prepare a specimen.
  • the electrical conductivity of the prepared specimens was measured using a four-point probe method, and the results are shown in Table 4 below.
  • the electrical conductivity of a pure poly (methyl methacrylate) prepared in Comparative Example 1 is an insulating, electrical conductivity was found to be 1.75 X 10 -12 S / cm.
  • the composites prepared in Examples 1 to 6 according to the present invention are prepared by adding modified amphoteric graphene to form a graphene shell on the surface of polymethylmethacrylate when polymethylmethacrylate is prepared. It can be seen that the conductivity is improved by 3.1 ⁇ 10 7 to 9.0 ⁇ 10 10 times. In addition, in the case of the composite prepared by mixing the polyacrylate and the amphoteric graphene in Comparative Examples 2 to 7, it can be seen that the 1.2 to 5.7 ⁇ 10 5 times improved.
  • the graphene-polymer composite according to the present invention can achieve a significantly superior electrical conductivity compared to the composite prepared by mixing the polymerized polymer and amphoteric graphene by performing polymerization from a mixture of monomer and amphoteric graphene. It can be seen that.
  • the method for preparing a graphene-polymer composite according to the present invention by using graphene having 0.2 ⁇ n ⁇ 60 hydrophilic groups introduced on the surface of 100 graphene carbon atoms, a separate interfacial stabilizer, dispersion stabilizer, etc.
  • a separate interfacial stabilizer, dispersion stabilizer, etc. In addition to improving the dispersibility of graphene without the use of, it is possible to minimize the deformation of the carbon-carbon double bonds delocalized on the graphene surface. Accordingly, the graphene-polymer composite prepared is excellent in electrical conductivity even if it contains a small amount of graphene, it can be usefully used in various fields that require electrical conductivity.
  • the graphene-polymer composite according to the present invention has a low physical property inherent in graphene, so that excellent electrical conductivity is realized even when a small amount of graphene is contained, and thus may be usefully used in various fields requiring electrical conductivity.

Abstract

The present invention relates to a graphene-polymer composite and a method for preparing the same. The present invention can enhance the dispersion force of graphene without separately using a surfactant or a dispersion stabilizer and minimize the transformation of carbon-carbon double bonds that are delocalized on the surface of the graphene, by using graphene having a surface to which n (0.2 ≤ n ≤ 60) hydrophilic groups on the basis of 100 graphene carbon atoms are introduced, when the graphene-polymer composite is prepared. Therefore, the prepared graphene-polymer composite has excellent electrical conductivity even though it contains a small amount of graphene, and thus can be favorably used in various fields requiring electrical conductivity.

Description

그래핀-고분자 복합체 및 이의 제조방법Graphene-polymer composite and preparation method thereof
본 발명은 그래핀-고분자 복합체 및 이의 제조방법에 관한 것으로, 상세하게는 고분자 코어; 및 양쪽성 그래핀을 함유하는 쉘로 구성되어 전기 전도성이 우수한 그래핀-고분자 복합체 및 이의 제조방법에 관한 것이다.The present invention relates to a graphene-polymer composite and a method for preparing the same, specifically, a polymer core; And it consists of a shell containing the amphoteric graphene relates to a graphene-polymer composite excellent in electrical conductivity and a method for producing the same.
그래핀(graphene)은 우수한 물성을 갖는 새로운 나노소재로서, 최근 여러 분야에서 이를 응용하기 위한 연구가 활발히 진행되고 있다. 구체적으로, 그래핀은 1 TPa의 모듈러스, 106 S/cm의 전기전도도, 5000 W/m·K의 열전도도, 2600 m2/g의 넓은 표면적 등의 뛰어난 물성을 가져 다양한 분야에서 응용될 수 있는 잠재력이 우수하다. 2004년 이전까지만 해도 그래핀은 독립적으로 존재할 수 없는 물질로 알려져 있어 이론적 연구만이 수행되어 왔으나, 2004년 세계 최초로 맨체스터 대학의 Geim 그룹이 그래핀의 존재를 확인한 이후, 그래핀은 새로운 도전성 나노재료로 각광받으면서 다양한 연구들이 세계적으로 행해지고 있다.Graphene (graphene) is a new nanomaterial having excellent physical properties, and researches for applying it in various fields have been actively conducted in recent years. Specifically, graphene has excellent properties such as a modulus of 1 TPa, an electrical conductivity of 10 6 S / cm, a thermal conductivity of 5000 W / m · K, and a large surface area of 2600 m 2 / g. The potential is excellent. Until 2004, graphene is known to be a material that cannot exist independently. Only theoretical studies have been carried out, but since the Geim Group at the University of Manchester in 2004 confirmed the existence of graphene, graphene is a new conductive nanomaterial. In the spotlight, various studies are being conducted worldwide.
최근, 이러한 그래핀의 우수한 물성을 이용하기 위하여 그래핀을 고분자와 혼합하여 제조되는 복합체들이 개발되고 있다. 상기 복합체는 그래핀에 의해 다양한 물성이 구현될 뿐만 아니라, 사용되는 용도에 따라 그 구조를 적절히 조절함으로써 원하는 물성을 극대화할 수 있으므로 신소재로서 각광받고 있다. 구조 조절을 통한 물성제어를 예를 들면, 기계적 강도가 요구되는 소재의 경우, 고분자 매트릭스에 그래핀을 분산시켜 그래핀과 고분자의 계면 면적을 극대화함으로써 계면에서의 그래핀과 고분자 사이의 상호작용을 최적화하여 우수한 기계적 강도를 구현할 수 있다. 또한, 전기 전도성이 요구되는 소재의 경우, 고분자 매트릭스에 그래핀의 응집에 의해서 도전채널이 형성되도록 고분자 입자에 그래핀이 코팅된 구조를 갖는 것이 소량의 그래핀을 사용하더라도 보다 우수한 전기 전도성을 구현할 수 있다.Recently, composites prepared by mixing graphene with a polymer have been developed in order to use the excellent physical properties of graphene. The composite is not only a variety of physical properties by the graphene, but also to attract the attention as a new material because it can maximize the desired physical properties by appropriately adjusting the structure according to the use. For example, in the case of a material requiring mechanical strength through structural control, dispersing graphene in a polymer matrix to maximize the interface area between graphene and the polymer, thereby improving the interaction between the graphene and the polymer at the interface. Optimal mechanical strength can be achieved by optimization. In addition, in the case of a material requiring electrical conductivity, having a structure in which the graphene is coated on the polymer particles so that the conductive channel is formed by agglomeration of the graphene in the polymer matrix may be achieved even though a small amount of graphene is used. Can be.
그러나, 이러한 이점에도 불구하고 흑연계 물질들은 고분자 내에서 균일하게 분산되지 않고 응집하여 고유의 물성을 구현되지 않으므로, 상용화가 늦어지고 있다. 이에 따라 흑연계, 특히 그래핀의 분산성 및 상용성을 향상시키기 위한 다양한 연구들이 진행되고 있으며, 최근 그 결과들이 속속 발표되고 있다.However, despite these advantages, graphite-based materials do not uniformly disperse in the polymer and do not aggregate to realize their inherent physical properties, and thus, commercialization is delayed. Accordingly, various studies have been conducted to improve the dispersibility and compatibility of graphite, in particular graphene, and the results are recently published one after another.
먼저, 대한민국 공개특허 제2013-0125388호는 표면에 복수계의 작용기를 포함하는 산화그래핀 또는 산화흑연을 중합반응의 촉매로서 사용하여 고분자 매트릭스 내에 산화그래핀이 분산된 구조의 복합체를 제시하고 있다.First, Korean Patent Publication No. 2013-0125388 proposes a composite having a structure in which graphene oxide is dispersed in a polymer matrix using graphene oxide or graphite oxide including a plurality of functional groups on its surface as a catalyst for polymerization. .
다음으로, 대한민국 공개특허 제2010-0109258호는 이온성 관능기로 개질된 고분자 미립자와 표면에 이온성 관능기로 개질된 그래핀을 이온결합시켜 고분자 미립자를 그래핀으로 코팅시킨 전기 전도성 입자를 제시하고 있다.Next, Korean Patent Laid-Open Publication No. 2010-0109258 proposes an electrically conductive particle coated with graphene by polymer binding the polymer fine particles modified with an ionic functional group and the graphene modified with an ionic functional group on the surface. .
다음으로, "Graphene Attached on Microsphere Surface for Thermally Conductive Composite Material, Jae-Yong Choi, et.al., Clean Technology, Vol.19, No.3, 243"은 마이크로플루이딕(microfluidic)으로 균일한 미립자를 제조하는데 있어 수분산을 통하여 계면안정제가 도입된 그래핀 용액을 연속상(water phase)으로 사용하여 표면에 그래핀이 분포된 폴리메틸메타크릴레이트 미립자를 제조하는 기술을 제시하고 있다.Next, "Graphene Attached on Microsphere Surface for Thermally Conductive Composite Material, Jae-Yong Choi, et.al., Clean Technology, Vol. 19, No. 3, 243" is a microfluidic material for uniform particles. In the preparation, a technique for preparing polymethyl methacrylate microparticles having graphene distribution on the surface by using a graphene solution having an interfacial stabilizer introduced through a water dispersion as a water phase is proposed.
그러나, 앞서 설명한 바와 같이, 전기 전도성 면에서 고분자 매트릭스에 그래핀이 분산된 구조는 고분자 코어를 그래핀이 코팅한 구조의 복합체에 비하여 그 물성이 떨어지며, 산화그래핀 역시 환원된 그래핀과 대비하여 전기 전도성이 낮은 문제가 있다. 또한, 그래핀의 분산력을 향상시키기 위하여 그래핀 표면에 친수성을 갖도록 개질하는 경우, 별도의 반응점을 추가하기 위하여 그래핀 고유의 비편재화된 탄소-탄소 이중결합의 변형이 수반되며, 이로 인하여 그래핀 고유의 물성이 감소되어 고분자 복합체에 구현되는 물성이 미미할 수 있다. 아울러, 계면안정제 또는 분산안정제를 사용하는 경우, 최종적으로 제조되는 고분자 복합체 표면에 잔류하여 그래핀에 의해 구현되는 물성이 저하될 수 있는 문제가 있다.However, as described above, the structure in which graphene is dispersed in the polymer matrix in terms of electrical conductivity is inferior in physical properties to the composite of the graphene-coated structure, and graphene oxide is also compared with the reduced graphene. There is a problem of low electrical conductivity. In addition, when modifying to have a hydrophilicity on the graphene surface in order to improve the dispersibility of the graphene, it is accompanied by a modification of the graphene inherent delocalized carbon-carbon double bond to add a separate reaction point, thereby Intrinsic physical properties may be reduced, resulting in insignificant physical properties of the polymer composite. In addition, in the case of using the interfacial stabilizer or dispersion stabilizer, there is a problem that the physical properties implemented by the graphene may be reduced by remaining on the surface of the finally prepared polymer composite.
따라서, 전기 전도성이 우수한 그래핀-고분자 복합체를 제조하기 위하여 그래핀의 분산력을 향상시키기 위해 수행되는 그래핀의 표면 개질, 및 안정제 사용에 따른 그래핀 고유의 물성 저하를 최소화하여 우수한 물성을 구현할 수 있는 기술의 개발이 절실히 요구되고 있다.Therefore, in order to prepare the graphene-polymer composite having excellent electrical conductivity, it is possible to realize excellent physical properties by minimizing the surface modification of graphene, which is performed to improve the dispersibility of graphene, and the degradation of the inherent properties of graphene due to the use of a stabilizer. There is an urgent need for the development of technology.
본 발명의 목적은 그래핀 고유의 물성이 저하되지 않아 전기 전도도가 우수한 그래핀-고분자 복합체를 제공하는데 있다.An object of the present invention is to provide a graphene-polymer composite having excellent electrical conductivity since the physical properties of graphene are not degraded.
본 발명의 다른 목적은 그래핀의 분산력을 향상시키기 위한 안정제의 사용 없이 수행되는 상기 그래핀-고분자 복합체의 제조방법을 제공하는데 있다.Another object of the present invention is to provide a method for producing the graphene-polymer composite that is performed without the use of a stabilizer to improve the dispersibility of graphene.
상기 목적을 달성하기 위하여,In order to achieve the above object,
본 발명은 일실시예에서,The present invention in one embodiment,
고분자 코어; 및Polymer cores; And
양쪽성 그래핀으로 구성되는 쉘을 포함하고,Including a shell composed of amphoteric graphene,
상기 양쪽성 그래핀은 그래핀 탄소 원자 100개에 대하여 하기 수학식 1을 만족하는 n개의 친수성기를 포함하는 그래핀-고분자 복합체를 제공한다:The amphoteric graphene provides a graphene-polymer composite including n hydrophilic groups satisfying Equation 1 for 100 graphene carbon atoms:
[수학식 1][Equation 1]
0.2 ≤ n ≤ 60.0.2 ≦ n ≦ 60.
또한, 본 발명은 일실시예에서,In addition, the present invention in one embodiment,
비닐계 단량체, 개시제 및 양쪽성 그래핀을 포함하는 혼합물의 중합반응을 수행하여 그래핀-고분자 복합체를 제조하는 상기 그래핀-고분자 복합체의 제조방법을 제공한다.It provides a graphene-polymer composite manufacturing method for producing a graphene-polymer composite by performing a polymerization reaction of a mixture containing a vinyl monomer, an initiator and amphoteric graphene.
본 발명에 따른 그래핀-고분자 복합체는, 코어인 고분자를 그래핀 탄소 원자 100개에 대하여 0.2≤n≤60개의 친수성기가 표면에 도입된 양쪽성 그래핀으로 코팅시킨 구조를 가져 그래핀 고유의 물성저하가 없으며, 소량의 그래핀을 함유하여도 우수한 전기 전도성이 구현되므로, 전기 전도성이 요구되는 다양한 분야에서 유용하게 사용될 수 있다.The graphene-polymer composite according to the present invention has a structure in which a polymer, which is a core, is coated with amphoteric graphene having 0.2 ≦ n ≦ 60 hydrophilic groups introduced on its surface with respect to 100 graphene carbon atoms, thereby inherent in graphene. There is no deterioration and excellent electrical conductivity is realized even when a small amount of graphene is contained, and thus may be usefully used in various fields requiring electrical conductivity.
도 1은 본 발명에 따른 하나의 실시예에서, 쉘을 구성하는 양쪽성 그래핀을 얻기 위해 수행되는 개질 반응을 도시한 이미지이다;1 is an image showing a reforming reaction performed to obtain amphoteric graphene constituting the shell in one embodiment according to the present invention;
도 2는 본 발명에 따른 하나의 실시예에서 제조되는 그래핀-고분자 복합체를 주사전자현미경(SEM) 분석한 이미지이다: 이때, (a)는 150 배율의 이미지이고, (b)는 3,000 배율의 이미지이다.Figure 2 is a scanning electron microscope (SEM) analysis of the graphene-polymer composite prepared in one embodiment according to the present invention: (a) is an image of 150 magnification, (b) is a 3,000 magnification Image.
본 발명은 다양한 변경을 가할 수 있고 여러 가지 실시예를 가질 수 있는 바, 특정 실시예들을 도면에 예시하고 상세한 설명에 상세하게 설명하고자 한다.As the invention allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the written description.
그러나, 이는 본 발명을 특정한 실시 형태에 대해 한정하려는 것이 아니며, 본 발명의 사상 및 기술 범위에 포함되는 모든 변경, 균등물 내지 대체물을 포함하는 것으로 이해되어야 한다.However, this is not intended to limit the present invention to specific embodiments, it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.
본 발명에서, "포함한다" 또는 "가지다" 등의 용어는 명세서상에 기재된 특징, 숫자, 단계, 동작, 구성요소, 부품 또는 이들을 조합한 것이 존재함을 지정하려는 것이지, 하나 또는 그 이상의 다른 특징들이나 숫자, 단계, 동작, 구성요소, 부품 또는 이들을 조합한 것들의 존재 또는 부가 가능성을 미리 배제하지 않는 것으로 이해되어야 한다.In the present invention, the terms "comprises" or "having" are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, and one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, components, or a combination thereof.
또한, 본 발명에서 첨부된 도면은 설명의 편의를 위하여 확대 또는 축소하여 도시된 것으로 이해되어야 한다.In addition, it is to be understood that the accompanying drawings in the present invention are shown enlarged or reduced for convenience of description.
이하, 본 발명에 대하여 도면을 참고하여 상세하게 설명하고, 도면 부호에 관계없이 동일하거나 대응하는 구성 요소는 동일한 참조 번호를 부여하고 이에 대한 중복되는 설명은 생략하기로 한다.Hereinafter, the present invention will be described in detail with reference to the accompanying drawings, and the same or corresponding components will be given the same reference numerals regardless of the reference numerals, and redundant description thereof will be omitted.
본 발명에서, "phr"란, 코어인 고분자 또는 중합반응에 사용된 단량체를 기준으로 하여, 100 중량부당 사용되는 양쪽성 그래핀의 함량(Parts per Hundred Resin)을 의미한다.In the present invention, "phr" refers to the content of amphoteric graphene (Parts per Hundred Resin) used per 100 parts by weight based on the core polymer or the monomer used in the polymerization reaction.
또한, 본 발명에서 "안정제"란, 물을 분산 매질로 하여 수행되는 중합반응에 있어서, 중합에 사용되는 단량체 또는 제조되는 중합체가 액적, 미립자 등의 형상을 안정적으로 유지할 수 있도록 첨가되는 첨가제를 의미한다. 구체적으로 상기 안정제로는 예를 들면, 반응용매와 유기 단량체의 에멀젼을 안정적으로 형성하기 위하여 유화중합 반응에서 사용되는 유화제 또는 계면활성제; 반응용매 내에서 유기 단량체의 액적을 안정적으로 형성하기 위하여 현탁중합 반응에서 사용되는 분산제; 또는 중합에 의해 형성되는 미립자가 분산매 내에서 응집하는 것을 방지하기 위하여 분산중합 반응에서 사용되는 입자 안정제 등을 들 수 있다.In addition, in the present invention, "stabilizer" refers to an additive in which a monomer or polymer used for polymerization is stably maintained in the shape of droplets or fine particles in a polymerization reaction performed with water as a dispersion medium. do. Specifically, the stabilizer may include, for example, an emulsifier or a surfactant used in an emulsion polymerization reaction to stably form an emulsion of a reaction solvent and an organic monomer; Dispersants used in the suspension polymerization reaction to stably form droplets of organic monomers in the reaction solvent; Or particle stabilizers used in the dispersion polymerization reaction in order to prevent the fine particles formed by polymerization from agglomerating in the dispersion medium.
나아가, 본 발명에서 "양쪽성"이란, 한 분자 또는 하나의 입자 내에서 친수성과 소수성; 또는 친수성과 친유성을 동시에 나타내는 것을 의미한다. 예를 들면, 본 발명에 따른 "양쪽성 그래핀"은 소수성인 그래핀에 COO- 또는 SO3 -을 도입하여 친수성을 부여함으로써 소수성 및 친수성이 모두 구현된 그래핀을 말한다.Further, in the present invention, "bilateral" means hydrophilicity and hydrophobicity in one molecule or one particle; Or it means showing both hydrophilicity and lipophilic at the same time. For example, "bilateral graphene" according to the present invention refers to graphene in which both hydrophobicity and hydrophilicity are implemented by imparting hydrophilicity by introducing COO - or SO 3 - to hydrophobic graphene.
본 발명은 그래핀-고분자 복합체 및 이의 제조방법에 관한 것이다.The present invention relates to a graphene-polymer composite and a preparation method thereof.
그래핀(graphene)은 뛰어난 물성을 가져 최근 다양한 분야에서 관심을 받고 있는 소재이다. 그러나, 이러한 이점에도 불구하고 흑연계 물질들은 고분자 내에 잘 분산되지 않고 응집되어 원하는 물성이 효과적으로 구현되지 않으므로 실질적인 상용화가 늦어지고 있다. 현재까지 이를 개선하기 위한 많은 연구들이 진행되었으며, 그 결과로서 그래핀 표면을 개질하여 수분산성을 향상시키거나 안정제를 사용하여 그래핀의 분산을 제어하는 기술 등이 발표되었다. 그러나, 그래핀을 개질하는 경우, 표면에 별도의 반응점이 요구되므로 그래핀 표면에 비편재화된 탄소-탄소 이중결합의 변형이 수반되고, 안정제를 사용하는 경우, 최종적으로 제조되는 복합체 내에 안정제가 잔류할 수 있으므로 복합체에 구현되는 그래핀 고유의 물성이 저하되는 문제가 있다.Graphene is a material that has recently attracted attention in various fields because of its excellent physical properties. However, despite these advantages, the graphite-based materials are not dispersed well in the polymer and are aggregated so that the desired physical properties are not effectively realized. To date, many studies have been conducted to improve this. As a result, techniques for improving the dispersibility of water by improving the surface of graphene or controlling the dispersion of graphene using a stabilizer have been published. However, when modifying graphene, since a separate reaction point is required on the surface, a deformation of carbon-carbon double bonds delocalized on the surface of graphene is accompanied, and when stabilizers are used, stabilizers remain in the finally prepared composite. Since there is a problem that the inherent physical properties of the graphene is implemented in the composite.
이에, 본 발명은 그래핀 고유의 물성 저하를 최소화하여 전기 전도성이 우수한 그래핀-고분자 복합체 및 이의 제조방법을 제안한다.Thus, the present invention proposes a graphene-polymer composite having excellent electrical conductivity and a method of manufacturing the same by minimizing the degradation of inherent properties of graphene.
본 발명은, 그래핀-고분자 복합체의 제조 시 그래핀 탄소 원자 100개에 대하여 0.2≤n≤60개의 친수성기가 표면에 도입된 그래핀을 사용함으로써, 계면안정제, 분산안정제 등을 사용하지 않고 그래핀의 분산력을 향상시킬 수 있을 뿐만 아니라, 그래핀 표면에 비편재화된 탄소-탄소 이중결합의 변형을 최소화할 수 있다. 이에 따라 제조되는 그래핀-고분자 복합체는 소량의 그래핀을 함유하여도 전기 전도성이 우수하므로, 전기 전도성이 요구되는 다양한 분야에서 유용하게 사용될 수 있다.In the present invention, by using graphene having 0.2 ≦ n ≦ 60 hydrophilic groups introduced to the surface of 100 graphene carbon atoms in the preparation of the graphene-polymer composite, graphene is not used without using an interfacial stabilizer, dispersion stabilizer, or the like. In addition to improving the dispersibility of the carbon, it is possible to minimize the deformation of the carbon-carbon double bonds delocalized on the graphene surface. Since the graphene-polymer composite prepared according to the present invention has excellent electrical conductivity even when a small amount of graphene is contained, it may be usefully used in various fields requiring electrical conductivity.
이하, 본 발명을 보다 상세히 설명한다.Hereinafter, the present invention will be described in more detail.
본 발명은 일실시예에서, 고분자 코어; 및The invention in one embodiment, a polymer core; And
양쪽성 그래핀(graphene)으로 구성되는 쉘을 포함하고,A shell composed of amphoteric graphene,
상기 양쪽성 그래핀은 그래핀 탄소 원자 100개에 대하여 하기 수학식 1을 만족하는 n개의 친수성기를 포함하는 그래핀-고분자 복합체를 제공한다:The amphoteric graphene provides a graphene-polymer composite including n hydrophilic groups satisfying Equation 1 for 100 graphene carbon atoms:
[수학식 1][Equation 1]
0.2 ≤ n ≤ 60.0.2 ≦ n ≦ 60.
상기 그래핀-고분자 복합체는 고분자 코어와 이를 코팅하고 있는 양쪽성 그래핀으로 구성되는 쉘을 포함할 수 있다. 여기서, 쉘을 이루는 상기 그래핀은 표면에 친수성기가 도입되어 양쪽성을 갖는 것일 수 있다. 그래핀 표면에 친수성기를 도입하기 위하여 종래 수행되었던 기술들은 그래핀 표면에 비편재화된 탄소-탄소 이중결합을 변형시키므로, 그래핀 고유의 물성이 저하될 수 있다. 그러나, 본 발명에서 사용되는 양쪽성 그래핀은 그래핀 표면에 비편재화된 탄소-탄소 이중결합을 변형시키지 않고, 그래핀 표면에 잔존하는 반응성기, 구체적으로는 그래핀 표면에 잔류하는 에폭시기를 이용하여 표면 개질한 것으로, 그래핀 탄소 원자 100개에 대하여 0.2 내지 60개의 친수성기가 도입될 수 있다. 보다 구체적으로는 0.2 내지 40개; 0.2 내지 30개; 또는 0.2 내지 20개의 친수성기가 도입될 수 있다. 상기 친수성기의 도입량은 상기 범위 내에서 그래핀 표면의 비편재화된 탄소-탄소 이중결합을 변형을 방지하여 그래핀 고유의 물성을 유지시킬 수 있으며, 그래핀 표면에 부여되는 친수성과 그래핀 자체의 소수성 비율을 효과적으로 제어하여 양쪽성을 가질 수 있다.The graphene-polymer composite may include a shell composed of a polymer core and amphoteric graphene coating the same. Here, the graphene forming the shell may be a hydrophilic group introduced into the surface having an amphoteric. Conventionally performed techniques for introducing a hydrophilic group on the graphene surface deforms the unlocalized carbon-carbon double bond on the graphene surface, thereby degrading the inherent physical properties of the graphene. However, the amphoteric graphene used in the present invention does not modify carbon-carbon double bonds unlocalized on the graphene surface, and uses reactive groups remaining on the graphene surface, specifically, epoxy groups remaining on the graphene surface. By surface modification, 0.2 to 60 hydrophilic groups may be introduced for 100 graphene carbon atoms. More specifically 0.2 to 40; 0.2 to 30; Or 0.2 to 20 hydrophilic groups may be introduced. The introduction amount of the hydrophilic group can maintain the inherent physical properties of graphene by preventing deformation of the unlocalized carbon-carbon double bond on the graphene surface within the above range, the hydrophilicity imparted to the graphene surface and the hydrophobicity of graphene itself The ratio can be effectively controlled to have amphotericity.
이때, 본 발명에 따른 상기 친수성기는, 그래핀의 표면에 친수성을 유도할 수 있는 치환기라면 특별히 제한하는 것은 아니나, 구체적으로는 COO-M+ 및 SO3 -M+ 중 어느 하나 이상을 포함할 수 있으며, 상기 M은 H; Li, Na, K, Rb, Cs 등의 알칼리 금속; 또는 4차 아민일 수 있다.At this time, the hydrophilic group according to the present invention is not particularly limited as long as it is a substituent capable of inducing hydrophilicity on the surface of graphene, specifically, may include any one or more of COO - M + and SO 3 - M + . M is H; Alkali metals such as Li, Na, K, Rb and Cs; Or quaternary amines.
또한, 본 발명에 따른 그래핀-고분자 복합체에 있어서, 쉘을 구성하는 그래핀의 함량은 코어인 고분자 입자의 수분산을 안정시키면서 전기 전도성을 향상시킬 수 있는 양이라면 특별히 제한되는 것은 아니라, 구체적으로는 고분자 코어에 대하여 0.1 내지 10 phr일 수 있다. 보다 구체적으로는 0.1 내지 8 phr; 0.2 내지 6 phr; 또는 0.3 내지 5 phr일 수 있다.In addition, in the graphene-polymer composite according to the present invention, the content of graphene constituting the shell is not particularly limited as long as it is an amount capable of improving the electrical conductivity while stabilizing the water dispersion of the polymer particles as the core. May be 0.1 to 10 phr relative to the polymer core. More specifically 0.1 to 8 phr; 0.2 to 6 phr; Or 0.3 to 5 phr.
나아가, 본 발명에 따른 상기 그래핀-고분자 복합체는,Furthermore, the graphene-polymer composite according to the present invention,
고분자 코어에 대한 그래핀(graphene)의 함량이 1 phr인 그래핀-고분자 복합체에 대하여,For the graphene-polymer composite having a graphene content of 1 phr for the polymer core,
전기 전도도(L) 평가 시, 하기 수학식 2를 만족할 수 있다:In evaluating the electrical conductivity (L), the following Equation 2 may be satisfied:
[수학식 2][Equation 2]
L ≥ 1.0 × 10-8 L ≥ 1.0 × 10 -8
여기서, 상기 전기 전도도(L)의 단위는 S/cm이다.Here, the unit of the electrical conductivity (L) is S / cm.
하나의 실시예에서, 양쪽성 그래핀의 함량이 고분자 코어에 대하여 0.3 내지 5.0 phr인 본 발명에 따른 그래핀-고분자 복합체의 전기 전도도를 평가하였다. 그 결과, 고분자 코어에 대한 그래핀의 함량이 1 phr인 그래핀-고분자 복합체의 경우, 전기 전도도는 8.43 Ｘ 10-4 S/cm인 것으로 확인되었다. 또한, 코어로서 사용된 순수한 폴리메틸메타크릴레이트의 전기 전도도는 1.75 Ｘ 10-12 S/cm으로 전기 전도성이 현저히 낮은 반면, 본 발명에 따른 그래핀-고분자 복합체는 양쪽성 그래핀의 함유량에 따라 5.39 Ｘ 10-5 내지 1.57 Ｘ 10-1 S/cm의 전기 전도도를 나타내므로, 순수한 폴리메틸메타크릴레이트와 대비하여 3.1 Ｘ 107 내지 9.0 Ｘ 1010 배 우수한 전기 전도성을 갖는 것을 확인할 수 있다(실험예 2 참조).In one embodiment, the electrical conductivity of the graphene-polymer composite according to the present invention with an amphoteric graphene content of 0.3 to 5.0 phr relative to the polymer core was evaluated. As a result, in the case of the graphene-polymer composite having a graphene content of 1 phr to the polymer core, the electrical conductivity was found to be 8.43 Ｘ 10 -4 S / cm. In addition, the electrical conductivity of the pure polymethyl methacrylate used as the core is 1.75 Ｘ 10 -12 S / cm, the electrical conductivity is significantly lower, whereas the graphene-polymer composite according to the present invention is depending on the content of the amphoteric graphene 5.39 Ｘ 10 -5 to 1.57 Ｘ 10 -1 S / cm, the electrical conductivity of 3.1 Ｘ 10 7 to 9.0 Ｘ 10 10 times better than that of pure polymethylmethacrylate. Experimental Example 2).
이로부터, 본 발명에 따른 그래핀-고분자 복합체는 양쪽성 그래핀을 고분자 코어에 대하여 0.1 내지 10.0 phr의 소량을 포함하여도 우수한 전기 전도성을 구현할 수 있으며, 양쪽성 그래핀의 함량이 고분자 코어에 대하여 1 phr인 그래핀-고분자 복합체의 전기 전도도는 1.0 × 10-8 S/cm 이상, 구체적으로는 1.0 × 10-5 S/cm 이상, 보다 구체적으로는 1.0 × 10-4 S/cm 이상 또는 4.0 × 10-4 S/cm 이상 인 것을 알 수 있다.From this, the graphene-polymer composite according to the present invention can implement excellent electrical conductivity even when the amphoteric graphene is contained in a small amount of 0.1 to 10.0 phr relative to the polymer core, the content of the amphoteric graphene in the polymer core About 1 phr of graphene-polymeric electrical conductivity of the complex is 1.0 × 10 -8 S / cm or more, specifically 1.0 × 10 -5 S / cm or higher, more specifically from 1.0 × 10 -4 S / cm or more, or It turns out that it is 4.0 * 10 <-4> S / cm or more.
아울러, 본 발명에 따른 상기 고분자 코어는, 그 종류를 특별히 제한하는 것은 아니나, 구체적으로 예를 들면, 메틸아크릴레이트(methylacrylate, MA), 에틸아크릴레이트(ethylacrylate, EA), 부틸아크릴레이트(butylacrylate, BA), 메틸메타크릴레이트(methylmetacrylate, MMA), 에틸메타크릴레이트(ethylmetacrylate, EMA), 부틸메타크릴레이트(butylmetacrylate, BMA), 2-에틸헥실메타크릴레이트(2-ethylhexylmetacrylate, EHMA), 글리시딜메타크릴레이트(glycidyl methacrylate, GMA), 스티렌(styrene), 알파-메틸스티렌(α-methylstyrene), 염화비닐(vinylchloride), 염화비닐리덴(vinylidene chloride), 에틸렌(ethylene), 프로필렌(propylene) 등의 비닐계 단량체를 1종 이상 사용하여 중합되는 고분자일 수 있다.In addition, the polymer core according to the present invention is not particularly limited in kind, specifically, for example, methyl acrylate (methylacrylate, MA), ethyl acrylate (ethylacrylate, EA), butyl acrylate (butylacrylate, BA), methyl methacrylate (MMA), ethyl methacrylate (EMA), butyl methacrylate (BMA), 2-ethylhexyl methacrylate (EHMA), glycy Glycidyl methacrylate (GMA), styrene, alpha-methylstyrene, vinyl chloride, vinylidene chloride, ethylene, propylene, etc. It may be a polymer polymerized using at least one vinyl monomer of.
본 발명에 따른 그래핀-고분자 복합체는 그래핀 탄소 원자 100개에 대하여 0.2≤n≤60개의 친수성기가 표면에 도입된 양쪽성 그래핀을 포함하여 전기 전도성이 우수하므로, 절연성인 비닐계 중합체를 코어로서 사용하여도 우수한 전기 전도성을 나타낼 수 있다.The graphene-polymer composite according to the present invention includes an amphoteric graphene having 0.2 ≦ n ≦ 60 hydrophilic groups introduced on its surface with respect to 100 graphene carbon atoms, and thus has excellent electrical conductivity. It can be used as a good electrical conductivity.
또한, 본 발명은 일실시예에서,In addition, the present invention in one embodiment,
비닐계 단량체, 개시제 및 양쪽성 그래핀을 포함하는 혼합물의 중합반응을 수행하여 그래핀-고분자 복합체를 제조하는 그래핀-고분자 복합체의 제조방법을 제공한다.Provided is a method for preparing a graphene-polymer composite to prepare a graphene-polymer composite by carrying out a polymerization reaction of a mixture including a vinyl monomer, an initiator and amphoteric graphene.
보다 구체적으로 예를 들면, 비닐계 단량체인 메틸메타크릴레이트(methyl methacrylate, MMA), 개시제인 2,2-아조비스이소부티로니트릴(2,2-azobisisobutyronitrile, AIBN) 및 양쪽성 그래핀을 물에 혼합할 수 있다. 그 후, 상기 혼합물을 55 내지 85℃에서 중합하고, 중합에 의해 형성되는 분말을 여과 및 세척한 다음, 건조시켜 본 발명에 따른 그래핀-고분자 복합체를 제조할 수 있다.More specifically, for example, methyl methacrylate (MMA), a vinyl monomer, 2,2-azobisisobutyronitrile (AIBN), an initiator, and amphoteric graphene Can be mixed in. Thereafter, the mixture may be polymerized at 55 to 85 ° C., the powder formed by the polymerization may be filtered and washed, and then dried to prepare a graphene-polymer composite according to the present invention.
이때, 본 발명에 따른 상기 중합반응은, 분산중합, 유화중합 또는 현탁중합일 수 있다.In this case, the polymerization reaction according to the present invention may be dispersion polymerization, emulsion polymerization or suspension polymerization.
본 발명에 따른 그래핀-고분자 복합체의 제조방법은 양쪽성 그래핀을 사용함으로써, 별도의 안정제 사용 없이도 분산중합, 유화중합 또는 현탁중합을 수행할 수 있다. 보다 구체적으로, 상기 양쪽성 그래핀은 친수성 및 소수성(친유성과 동일)의 비율이 적절히 제어되어 중합반응의 반응용매로서 사용되는 물 내에서 소수성인 단량체가 안정적으로 미립자 또는 액적으로 존재할 수 있게 하는 "피커링 안정화제(Pickering Stabilizer)"의 역할을 수행한다. 상기 "피커링 안정화제(Pickering Stabilizer)"란 극성이 달라 서로 섞이지 않는 두 액체(예를 들면, 물과 기름 등)가 혼합된 혼합물에 분산된 마이크로 혹은 나노미터 크기의 고체 입자를 말하는데, 이때, 상기 고체 입자는 에멀젼 입자의 합일(coalescence)을 방지하기 위하여 물리적으로 안정화시키는 기능을 갖는다. 즉, 본 발명에 따른 양쪽성 그래핀은 코어인 고분자의 중합반응에서 단량체와 분산 매질인 물의 계면에 위치하여 단량체가 미립자를 형성하여 중합할 수 있도록 안정화시킬 수 있다. 따라서, 본 발명에 따른 그래핀-고분자 복합체의 제조방법은 양쪽성 그래핀을 사용함으로써 별도의 안정제를 사용하지 않고도 수행 가능하므로, 종래 분산중합, 유화중합 또는 현탁중합 시, 잔류하는 안정제가 존재하지 않아 그래핀 본연의 물성 저하를 최소화할 수 있다.In the method for preparing a graphene-polymer composite according to the present invention, by using amphoteric graphene, dispersion polymerization, emulsion polymerization or suspension polymerization can be performed without using a separate stabilizer. More specifically, the amphoteric graphene has a suitable ratio of hydrophilicity and hydrophobicity (the same as lipophilic) so that the hydrophobic monomer can be stably present in fine particles or droplets in water used as a reaction solvent of a polymerization reaction. Serves as a "Pickering Stabilizer". The “Pickering Stabilizer” refers to micro or nanometer-sized solid particles dispersed in a mixture of two liquids (eg, water and oil) that are different in polarity and do not mix with each other. Solid particles have the function of physically stabilizing to prevent coalescence of emulsion particles. That is, the amphoteric graphene according to the present invention can be stabilized so that the monomer can be formed and polymerized by being located at the interface between the monomer and the water of the dispersion medium in the polymerization reaction of the polymer as the core. Therefore, the method for preparing the graphene-polymer composite according to the present invention can be performed without using a separate stabilizer by using amphoteric graphene, and therefore, there is no remaining stabilizer in the conventional dispersion polymerization, emulsion polymerization or suspension polymerization. Therefore, it is possible to minimize the deterioration of the physical properties of graphene.
또한, 이렇게 제조되는 그래핀-고분자 복합체는, 중합된 고분자를 코어로 하여 양쪽성 그래핀(graphene)이 쉘을 구성하는 구조를 가질 수 있으며, 양쪽성 그래핀(graphene) 중 일부는 중합방식에 따라, 또는 양쪽성 그래핀(graphene)의 소수성 정도에 따라 코어인 고분자와 함께 복합체 내부에 존재할 수도 있다.In addition, the graphene-polymer composite thus prepared may have a structure in which the amphoteric graphene forms a shell by using the polymerized polymer as a core, and some of the amphoteric graphene is polymerized. Alternatively, or depending on the degree of hydrophobicity of the amphoteric graphene, it may be present in the composite together with the polymer that is the core.
한편, 본 발명에 따른 상기 양쪽성 그래핀은 친수성기를 함유하는 화합물로 표면 개질된 것일 수 있다.On the other hand, the amphoteric graphene according to the invention may be surface modified with a compound containing a hydrophilic group.
보다 구체적으로, 상기 양쪽성 그래핀은 상업적으로 구입할 수 있는 흑연 분말을 산화시키고, 이를 다시 환원하여 그래핀을 제조한 다음, 제조된 그래핀을 친수성기를 함유하는 화합물로 표면 개질하여 얻을 수 있다. 본 발명에 따른 양쪽성 그래핀은 환원된 그래핀에 잔류하는 산소를 포함하는 관능기, 즉 에폭시기를 활용할 수 있으므로 개질 시, 그래핀 표면에 비편재화된 탄소-탄소 이중결합의 변형 없이 그래핀 고유의 물성 저하를 최소화할 수 있으며, 친수성 및 소수성의 정도를 적절하게 제어할 수 있다.More specifically, the amphoteric graphene may be obtained by oxidizing a commercially available graphite powder, reducing it again to prepare graphene, and then surface modifying the prepared graphene with a compound containing a hydrophilic group. The amphoteric graphene according to the present invention can utilize a functional group containing oxygen remaining in the reduced graphene, that is, an epoxy group, so that when modified, it is inherent to graphene without deformation of the carbon-carbon double bonds delocalized on the graphene surface. Physical property degradation can be minimized and the degree of hydrophilicity and hydrophobicity can be controlled appropriately.
이때, 상기 흑연 분말을 산화시키는 방법으로는 예를 들면, NaClO3, KClO3, KMnO4 등의 산화제를 단독 또는 혼합하여 사용하거나, 또는 전기화학적 방법으로 산화시킬 수 있다. 이렇게 제조되는 산화흑연 분말은 탄소와 산소의 원소 비율이 1 내지 20 : 1일 수 있으나, 이에 제한되는 것은 아니다. 또한, 상기 산화흑연 분말은 층간 거리가 약 7 Å이므로, X선 회절 분석에서 관찰되는 피크의 2θ는 약 13±1°일 수 있으며, 산화흑연 분말의 산화 정도 및 수분 흡수 정도에 따라 오차가 발생할 수 있다.At this time, as the method for oxidizing the graphite powder is, for example, NaClO 3, KClO 3, KMnO 4, etc. can be used alone or in combination, or by electrochemical oxidation method for oxidizing agent. The graphite oxide powder thus prepared may have an element ratio of carbon to oxygen of 1 to 20: 1, but is not limited thereto. In addition, since the graphite oxide powder has an interlayer distance of about 7 μs, the 2 θ of the peak observed in the X-ray diffraction analysis may be about 13 ± 1 °, and the error may vary depending on the degree of oxidation and moisture absorption of the graphite oxide powder. May occur.
아울러, 상기 산화흑연을 환원하는 방법으로는 예를 들면, 비활성 기체 하에서 순간적으로 300℃ 이상의 고온 열처리하여 산화흑연을 구성하는 층들을 환원하고 팽윤 박리시키는 열 환원법; 또는 산화흑연을 액체 매질에 분산시키고 하이드라진(hydrazine) 등의 환원제로 환원시키는 화학적 환원법을 사용할 수 있으나, 이에 제한되는 것은 아니다.In addition, the method of reducing the graphite oxide, for example, a heat reduction method of reducing and swelling and peeling off the layers constituting the graphite oxide by heat treatment at a high temperature of 300 ℃ or more under an inert gas instantaneously; Alternatively, a chemical reduction method may be used in which the graphite oxide is dispersed in a liquid medium and reduced with a reducing agent such as hydrazine, but is not limited thereto.
나아가, 본 발명에 따른 상기 양쪽성 그래핀은 상기 산화흑연을 환원하여 제조된 그래핀을,Further, the amphoteric graphene according to the present invention is a graphene prepared by reducing the graphite oxide,
COO-M+ 및 SO3 -M+ 중 어느 하나 이상의 친수성기; 및Hydrophilic groups of any one or more of COO - M + and SO 3 - M + ; And
하나의 아민기를 포함하고,Contains one amine group,
상기 친수성기의 M은 H, Li, Na, K, Rb, Cs 또는 4차 아민인 친수성기를 함유하는 화합물로 개질하여 제조할 수 있다.M of the hydrophilic group can be prepared by modifying with a compound containing a hydrophilic group which is H, Li, Na, K, Rb, Cs or quaternary amine.
구체적으로, 도 1을 참조하면 산화흑연을 환원하여 제조되는 소수성인 그래핀은 표면에 에폭시기가 잔류할 수 있다. 따라서, 그래핀 표면에 잔류하는 에폭시기와, 친수성기인 SO3 -기 및 하나의 아민기를 포함하는 화합물, 예를 들면 2-아미노에탄술폰산와 같은 화합물을 반응시켜 그래핀의 표면을 개질함으로써, 양쪽성 그래핀을 제조할 수 있다.Specifically, referring to FIG. 1, the hydrophobic graphene prepared by reducing graphite oxide may have an epoxy group on a surface thereof. Therefore, the surface of graphene is modified by reacting an epoxy group remaining on the graphene surface with a compound containing a hydrophilic group, a SO 3 − group and one amine group, for example, 2-aminoethanesulfonic acid, thereby modifying the surface of the graphene. Pins can be manufactured.
이때, 그래핀 표면에 잔류하는 에폭시기와 반응하는 상기 화합물에 있어서, 친수성기인 COO- 또는 SO3 -은 소수성인 그래핀에 친수성을 부여하는 기능을 수행할 수 있다. 또한, 상기 친수성기를 함유하는 화합물의 아민기는 그래핀 표면에 잔존하는 에폭시기와 반응하여 그래핀의 표면을 개질하는 기능을 수행할 수 있다. 여기서, 상기 아민기가 2 이상인 경우, 에폭시기와 반응하고 남은 여분의 아민기가 또 다른 그래핀의 에폭시기와 반응하여 가교시킬 수 있으므로 아민기가 하나인 화합물을 사용할 수 있다.At this time, in the compound reacting with the epoxy group remaining on the graphene surface, the hydrophilic group COO - or SO 3 - may perform a function of imparting hydrophilicity to the hydrophobic graphene. In addition, the amine group of the compound containing a hydrophilic group may perform a function of reacting with the epoxy group remaining on the graphene surface to modify the surface of the graphene. Herein, when the amine group is 2 or more, since the remaining amine group reacted with the epoxy group may react with the epoxy group of another graphene and crosslink, the compound having one amine group may be used.
또한, 본 발명에 따른 상기 양쪽성 그래핀은, 그래핀 탄소 원자 100개에 대하여 하기 수학식 1을 만족하는 n개의 친수성기를 포함할 수 있다:In addition, the amphoteric graphene according to the present invention may include n hydrophilic groups satisfying Equation 1 for 100 graphene carbon atoms:
[수학식 1][Equation 1]
0.2 ≤ n ≤ 60.0.2 ≦ n ≦ 60.
본 발명에 따른 상기 양쪽성 그래핀은 그래핀 탄소 원자 100개에 대하여 0.2 내지 60개, 보다 구체적으로는 0.2 내지 40개; 0.2 내지 30개; 또는 0.2 내지 20개의 친수성기가 도입될 수 있다. 상기 양쪽성 그래핀은 탄소 원자 100개에 대하여 상기 범위 내의 친수성기를 도입함으로써, 개질된 그래핀의 친수성 및 친유성을 효율적으로 제어할 수 있으며, 이에 따라 코어인 고분자의 중합 시, "피커링 안정화제(Pickering Stabilizer)"의 역할을 수행할 수 있다.The amphoteric graphene according to the present invention is 0.2 to 60, more specifically 0.2 to 40 with respect to 100 graphene carbon atoms; 0.2 to 30; Or 0.2 to 20 hydrophilic groups may be introduced. The amphoteric graphene can efficiently control the hydrophilicity and lipophilicity of the modified graphene by introducing a hydrophilic group within the above range for 100 carbon atoms, and thus, during polymerization of the core polymer, (Pickering Stabilizer) ".
본 발명에 따른 그래핀-고분자 복합체의 제조방법에 있어서, 상기 그래핀(graphene)의 혼합량은, 중합되어 코어를 형성하는 고분자 입자의 수분산을 안정화시키고 전기 전도성을 향상시킬 수 있는 양이라면 특별히 제한되는 것은 아니나, 구체적으로는 비닐계 단량체에 대하여 0.1 내지 10 phr일 수 있다. 보다 구체적으로는 0.1 내지 8 phr; 0.2 내지 6 phr; 또는 0.3 내지 5 phr일 수 있다.In the method for producing a graphene-polymer composite according to the present invention, the mixing amount of the graphene (graphene) is particularly limited as long as it can stabilize the water dispersion and improve the electrical conductivity of the polymer particles polymerized to form the core. Although not necessarily, it may be specifically 0.1 to 10 phr relative to the vinyl monomer. More specifically 0.1 to 8 phr; 0.2 to 6 phr; Or 0.3 to 5 phr.
하나의 실시예에서, 양쪽성 그래핀의 함량이 고분자 코어에 대하여 0.3 내지 5.0 phr인 본 발명에 따른 그래핀-고분자 복합체의 전기 전도도를 평가하였다. 그 결과, 코어로서 사용된 순수한 폴리메틸메타크릴레이트의 전기 전도도는 1.75 Ｘ 10-12 S/cm으로 전기 전도성이 현저히 낮은 반면, 본 발명에 따른 그래핀-고분자 복합체는 5.39 Ｘ 10-5 내지 1.57 Ｘ 10-1 S/cm의 전기 전도도를 나타내므로, 순수한 폴리메틸메타크릴레이트와 대비하여 3.1 Ｘ 107 내지 9.0 Ｘ 1010 배 우수한 전기 전도성을 갖는 것을 확인할 수 있다(실험예 2 참조).In one embodiment, the electrical conductivity of the graphene-polymer composite according to the present invention with an amphoteric graphene content of 0.3 to 5.0 phr relative to the polymer core was evaluated. As a result, the electrical conductivity of pure polymethyl methacrylate used as the core, the electrical conductivity is significantly low as 1.75 X 10 -12 S / cm, while graphene in accordance with the present invention the polymer composite is 5.39 X 10 -5 to 1.57 Since it exhibits an electrical conductivity of Ｘ 10 −1 S / cm, it can be confirmed that the electric conductivity is 3.1 Ｘ 10 7 to 9.0 Ｘ 10 10 times superior to that of pure polymethylmethacrylate (see Experimental Example 2).
이로부터, 본 발명에 따른 그래핀-고분자 복합체는 양쪽성 그래핀을 고분자 코어에 대하여 0.1 내지 10.0 phr의 소량을 포함하여도 우수한 전기 전도성을 구현하는 것을 알 수 있다.From this, it can be seen that the graphene-polymer composite according to the present invention realizes excellent electrical conductivity even when the amphoteric graphene contains a small amount of 0.1 to 10.0 phr with respect to the polymer core.
또한, 본 발명에 따른 상기 그래핀-고분자 복합체의 제조방법에 따라 제조되는 그래핀-고분자 복합체의 크기는, 0.01 내지 10,000 μm일 수 있다. 구체적으로는 0.01 내지 1000 μm, 0.1 내지 500 μm, 0.1 내지 250 μm 또는 1 내지 250 μm일 수 있다.In addition, the size of the graphene-polymer composite prepared according to the method for producing the graphene-polymer composite according to the present invention may be 0.01 to 10,000 μm. Specifically, it may be 0.01 to 1000 μm, 0.1 to 500 μm, 0.1 to 250 μm or 1 to 250 μm.
하나의 실시예에서, 양쪽성 그래핀의 함량이 고분자 코어에 대하여 0.3 내지 5.0 phr인 본 발명에 따른 그래핀-고분자 복합체의 입도를 측정하였다. 그 결과, 본 발명에 따른 그래핀-고분자 복합체의 입도는 약 56.9 내지 226.1 μm이고, 그래핀-고분자 복합체 제조 시 양쪽성 그래핀의 첨가량이 증가함에 따라 제조되는 복합체의 입도가 감소하는 경향을 갖는 것을 확인할 수 있다(실험예 1 참조). 이는 안정제의 첨가량이 증가함에 따라 제조되는 중합체의 입도가 감소하는 분산중합, 유화중합 또는 현탁중합의 경향으로, 본 발명에 따른 제조방법은 별도의 안정화제를 사용하지 않아도 양쪽성 그래핀을 사용함으로써, 안정적으로 분산중합, 유화중합 또는 현탁중합을 수행할 수 있음을 의미한다.In one embodiment, the particle size of the graphene-polymer composite according to the invention was measured in which the amphoteric graphene content is 0.3 to 5.0 phr relative to the polymer core. As a result, the particle size of the graphene-polymer composite according to the present invention is about 56.9 to 226.1 μm, and the graphene-polymer composite has a tendency to decrease the particle size of the prepared composite as the amount of amphoteric graphene increases It can confirm that (refer experimental example 1). This is a tendency of dispersion polymerization, emulsion polymerization or suspension polymerization in which the particle size of the polymer produced decreases as the amount of stabilizer is increased, and the preparation method according to the present invention uses amphoteric graphene without using a separate stabilizer. This means that dispersion polymerization, emulsion polymerization or suspension polymerization can be performed stably.
본 발명에 따른 상기 비닐계 단량체는 그 종류를 특별히 제한하는 것은 아니나, 구체적으로 예를 들면, 메틸아크릴레이트(methylacrylate, MA), 에틸아크릴레이트(ethylacrylate, EA), 부틸아크릴레이트(butylacrylate, BA), 메틸메타크릴레이트(methylmetacrylate, MMA), 에틸메타크릴레이트(ethylmetacrylate, EMA), 부틸메타크릴레이트(butylmetacrylate, BMA), 2-에틸헥실메타크릴레이트(2-ethylhexylmetacrylate, EHMA), 글리시딜메타크릴레이트(glycidyl methacrylate, GMA), 스티렌(styrene), 알파-메틸스티렌(α-methylstyrene), 염화비닐(vinylchloride), 염화비닐리덴(vinylidene chloride), 에틸렌(ethylene), 프로필렌(propylene) 등을 사용할 수 있다.The vinyl monomer according to the present invention is not particularly limited in kind, but specifically, for example, methyl acrylate (methyl acrylate, MA), ethyl acrylate (ethyl acrylate, EA), butyl acrylate (butyl acrylate, BA) Methyl methacrylate (MMA), ethyl methacrylate (EMA), butyl methacrylate (BMA), 2-ethylhexyl methacrylate (EHMA), glycidyl methacrylate Glycidyl methacrylate (GMA), styrene, alpha-methylstyrene, vinyl chloride, vinylidene chloride, ethylene, propylene, etc. Can be.
이하, 본 발명을 실시예 및 실험예에 의해 보다 상세히 설명한다.Hereinafter, the present invention will be described in more detail with reference to Examples and Experimental Examples.
단, 하기 실시예 및 실험예는 본 발명을 예시하는 것일 뿐, 본 발명의 내용이 하기 실시예 및 실험예에 한정되는 것은 아니다.However, the following Examples and Experimental Examples are only illustrative of the present invention, and the content of the present invention is not limited to the following Examples and Experimental Examples.
제조예 1. 술폰산기로 개질된 양쪽성 그래핀의 제조Preparation Example 1 Preparation of Amphoteric Graphene Modified with Sulfonic Acid Group
단계 1: 그래핀(graphene)의 제조Step 1: Preparation of Graphene
1100℃, 질소 분위기 하에서, 평균 입자크기가 280 μm인 흑연을 1분간 팽창시켰다. 그 후, 팽창된 흑연(10 g)을 교반기 및 온도계가 도입된 1000 mL 반응조에 발연질산(200 mL)과 함께 주입하고, 0℃를 유지하면서 교반하였다. 교반을 수행하면서 염소산 칼륨(85 g)을 1시간에 걸쳐 천천히 투입하고, 상온에서 24시간 교반하면서 흑연을 산화시켰다. 산화된 흑연을 여과하고, 여액의 pH가 6이 되도록 증류수로 세척하였다. 세척된 산화흑연은 100℃, 진공 하에서 1일간 건조시키고, 건조된 산화흑연을 석영관에 투입하였다. 그런 다음, 질소 가스를 주입하고 1100℃의 전기로에 1분간 열 처리하여 산화흑연의 각 층이 대부분 얇은 박판 형태로 박리된 그래핀(graphene)을 얻었다. 이때, 제조된 그래핀의 평균 입자 크기는 8.4 μm이고, 원자 조성은 C10O0.86H0.65였다. Under 1100 ° C. and nitrogen atmosphere, graphite having an average particle size of 280 μm was expanded for 1 minute. Thereafter, the expanded graphite (10 g) was injected with fuming nitric acid (200 mL) into a 1000 mL reactor equipped with a stirrer and a thermometer, and stirred while maintaining 0 ° C. Potassium chlorate (85 g) was slowly added over 1 hour while stirring, and graphite was oxidized while stirring at room temperature for 24 hours. The oxidized graphite was filtered and washed with distilled water until the pH of the filtrate was 6. The washed graphite oxide was dried at 100 ° C. under vacuum for one day, and the dried graphite oxide was charged into a quartz tube. Then, nitrogen gas was injected and heat-treated in an electric furnace at 1100 ° C. for 1 minute to obtain graphene (graphene) in which each layer of graphite oxide was mostly peeled off in a thin sheet form. In this case, the average particle size of the prepared graphene is 8.4 μm, the atomic composition was C 10 O 0.86 H 0.65 .
단계 2: 술폰산기로 개질된 양쪽성 그래핀의 제조Step 2: Preparation of Amphoteric Graphene Modified with Sulfonic Acid Group
2-아미노에탄술폰산(20.0 g, 0.16 mol)과 수산화칼륨(KOH, 9.0 g, 0.16 mol)을 물(35 g)에 용해시킨 후, 30분 동안 교반하였다. 그 후, 상기 단계 1에서 제조된 그래핀(1 g)을 아세톤(150 mL)에 투입하고 1시간 동안 초음파 처리(sonication)하여 아세톤에 그래핀을 분산시켰다. 그래핀이 분산된 분산액과 2-아미노에탄술폰산이 용해된 상기 용액을 혼합하여 1시간 동안 교반하고, 혼합용액을 20분 동안 초음파 처리한 다음, 60℃에서 2일간 교반하여 용액 내의 그래핀을 표면 개질하였다. 개질이 완료되면, 혼합용액을 여과하여 그래핀을 분리하고, 분리된 그래핀을 뜨거운 물과 혼합된 아세톤으로 세척하였다. 그 후, 60℃, 진공 하에서 1일간 건조하여 친수성기인 술폰산기로 개질된 양쪽성 그래핀을 제조하였다. 이때, 개질된 양쪽성 그래핀의 평균 입자 크기는 8.4 μm이고, 원자 조성은 C10O1.03H1.21N0.14S0.13이였다.2-aminoethanesulfonic acid (20.0 g, 0.16 mol) and potassium hydroxide (KOH, 9.0 g, 0.16 mol) were dissolved in water (35 g) and stirred for 30 minutes. Then, graphene (1 g) prepared in step 1 was added to acetone (150 mL) and sonicated for 1 hour to disperse the graphene in acetone. The graphene-dispersed dispersion and the 2-aminoethanesulfonic acid solution were mixed and stirred for 1 hour, the mixed solution was sonicated for 20 minutes, and then stirred at 60 ° C. for 2 days to surface the graphene in the solution. Modified. When the modification was completed, the mixed solution was filtered to separate graphene, and the separated graphene was washed with acetone mixed with hot water. Thereafter, the mixture was dried under vacuum at 60 ° C. for 1 day to prepare amphoteric graphene modified with a sulfonic acid group which is a hydrophilic group. In this case, well-modified amphiphilic average particle size of the pin is 8.4 μm, and the atom composition yiyeotda C 10 O 1.03 H 1.21 N 0.14 S 0.13.
제조예 2. 카르복실기로 개질된 양쪽성 그래핀의 제조Preparation Example 2 Preparation of Amphoteric Graphene Modified by Carboxyl Group
상기 제조예 1의 단계 2에서 2-아미노에탄술폰산을 사용하는 대신에 6-아미노카프론산(21.0 g, 0.16 mol)을 사용한 것을 제외하고는 상기 제조예 1과 동일한 방법으로 수행하여 카르복실기로 개질된 양쪽성 그래핀을 제조하였다.A carboxyl group was modified in the same manner as in Preparation Example 1, except that 6-aminocaproic acid (21.0 g, 0.16 mol) was used instead of 2-aminoethanesulfonic acid in Step 2 of Preparation Example 1. Amphoteric graphene was prepared.
실시예 1 내지 실시예 6.Examples 1-6.
제조예 1에서 제조된 그래핀을 물(150 g)에 첨가하고 1시간 동안 초음파 처리하여 그래핀을 분산시킨 후, 비닐계 단량체인 메틸메타크릴레이트(MMA, 10 g)와 개시제인 2,2-아조비스이소부티로니트릴(AIBN, 0.15 g)이 혼합된 용액을, 그래핀이 분산된 분산액에 첨가하고, 2000 rpm의 속도로 5분간 교반하였다. 이때, 그래핀의 혼합량은 하기 표 1에 나타낸 바와 같이, 단량체에 대하여 0.3 내지 5.0 phr로 혼합되었다. 그 후, 70℃로 승온하고, 승온된 온도를 유지하면서 300 rpm으로 1일간 현탁중합 반응을 수행하였다. 반응이 완료되면 혼합액을 여과하여 그래핀이 코팅된 고분자 분말을 분리하고, 분리된 분말을 90℃, 진공 하에서 1일간 건조하여 본 발명에 따른 그래핀-폴리메틸메타크릴레이트 복합체 분말을 제조하였다.The graphene prepared in Preparation Example 1 was added to water (150 g) and sonicated for 1 hour to disperse the graphene, and then methyl methacrylate (MMA, 10 g) as a vinyl monomer and 2,2 as an initiator. A solution containing azobisisobutyronitrile (AIBN, 0.15 g) was added to a dispersion in which graphene was dispersed, and stirred at a speed of 2000 rpm for 5 minutes. At this time, the mixed amount of graphene was mixed in 0.3 to 5.0 phr relative to the monomer, as shown in Table 1 below. Thereafter, the temperature was raised to 70 ° C., and the suspension polymerization reaction was performed at 300 rpm for 1 day while maintaining the elevated temperature. Upon completion of the reaction, the mixed solution was filtered to separate the graphene-coated polymer powder, and the separated powder was dried at 90 ° C. for 1 day under vacuum to prepare a graphene-polymethylmethacrylate composite powder according to the present invention.
표 1
그래핀 혼합량 (phr)
실시예 1 0.3
실시예 2 0.5
실시예 3 1.0
실시예 4 2.0
실시예 5 3.0
실시예 6 5.0
Table 1
Graphene Blending Amount (phr)
Example 1 0.3
Example 2 0.5
Example 3 1.0
Example 4 2.0
Example 5 3.0
Example 6 5.0
비교예 1 내지 비교예 7.Comparative Example 1 to Comparative Example 7.
상기 제조예 1에서 제조된 그래핀을 아세톤(100 g)에 첨가하고, 1시간 동안 초음파 처리하여 그래핀을 분산시켰다. 그 후, 폴리메틸메타크릴레이트(PMMA, 10g)를 아세톤(250 g)에 녹인 용액을 상기 분산액에 첨가하고, 교반하여 혼합한 후, 아세톤을 제거하여 그래핀-폴리메틸메타크릴레이트 복합체 분말을 제조하였다. 이때, 그래핀의 혼합량은 하기 표 2에 나타낸 바와 같이, 비닐계 단량체에 대하여 0.0 내지 5.0 phr로 혼합되었다.Graphene prepared in Preparation Example 1 was added to acetone (100 g), and sonicated for 1 hour to disperse the graphene. Then, a solution of polymethyl methacrylate (PMMA, 10 g) dissolved in acetone (250 g) was added to the dispersion, stirred and mixed, and then acetone was removed to remove the graphene-polymethyl methacrylate composite powder. Prepared. At this time, as shown in Table 2, the mixed amount of graphene was mixed at 0.0 to 5.0 phr with respect to the vinyl monomer.
표 2
그래핀 혼합량 (phr)
비교예 1 0.0
비교예 2 0.3
비교예 3 0.5
비교예 4 1.0
비교예 5 2.0
비교예 6 3.0
비교예 7 5.0
TABLE 2
Graphene Blending Amount (phr)
Comparative Example 1 0.0
Comparative Example 2 0.3
Comparative Example 3 0.5
Comparative Example 4 1.0
Comparative Example 5 2.0
Comparative Example 6 3.0
Comparative Example 7 5.0
실험예 1. 그래핀-고분자 복합체의 형태 평가Experimental Example 1. Morphology evaluation of graphene-polymer complex
본 발명에 따른 그래핀-고분자 복합체의 형태를 평가하기 위하여 하기와 같은 실험을 수행하였다.In order to evaluate the morphology of the graphene-polymer complex according to the present invention, the following experiment was performed.
상기 실시예 1 내지 실시예 6에서 제조된 그래핀-폴리메틸메타크릴레이트 복합체 분말을 대상으로 주사전자현미경(SEM) 분석을 수행하였으며, 분석된 결과 중 실시예 5에서 제조된 그래핀-폴리메틸메타크릴레이트 복합체의 분석 결과를 도 2에 나타내었다. 또한, 입도 측정기(Mastersizer Hydro 2000MU, Malvern)를 이용하여 실시예에서 제조된 상기 그래핀-폴리메틸메타크릴레이트 복합체 분말의 입도를 측정하였으며, 측정된 결과를 하기 표 3에 나타내었다.Scanning electron microscope (SEM) analysis was performed on the graphene-polymethylmethacrylate composite powder prepared in Examples 1 to 6, and the graphene-polymethyl prepared in Example 5 of the analyzed results. The analysis results of the methacrylate complex are shown in FIG. 2. In addition, the particle size of the graphene-polymethyl methacrylate composite powder prepared in Example was measured using a particle size analyzer (Mastersizer Hydro 2000MU, Malvern), the measured results are shown in Table 3 below.
도 2 및 표 3에 나타낸 바와 같이, 본 발명에 따른 그래핀-고분자 복합체는 양쪽성 그래핀이 코어인 폴리메틸메타크릴레이트를 코팅하여 쉘을 이루는 입자 형태를 가지며, 별도의 안정제를 사용하지 않고도 현탁중합 반응에 의해 안정적으로 제조되는 것을 알 수 있다.As shown in FIG. 2 and Table 3, the graphene-polymer composite according to the present invention has a particle form of a shell formed by coating polymethyl methacrylate, which is an amphoteric graphene core, without using a separate stabilizer It can be seen that it is stably produced by the suspension polymerization reaction.
보다 구체적으로, 도 2를 참조하면 도 2의 (a)는 실시예 5에서 제조된 그래핀-폴리메틸메타크릴레이트 복합체를 150 배율로 주사전자현미경 분석한 것으로, 상기 복합체는 표면이 거친 구형의 입자인 것을 확인할 수 있다. 또한, 상기 도 2의 (b)는 상기 (a)를 20배 확대한 것(3,000 배율)으로서, 개질된 양쪽성 그래핀은 폴리메틸메타크릴레이트를 코팅하여 쉘을 형성하고 있으며, (b)의 표시된 부분과 같이 일부 박리된 형태를 갖는 것을 확인할 수 있다.More specifically, referring to Figure 2 (a) is a scanning electron microscope analysis of the graphene-polymethyl methacrylate complex prepared in Example 5 at 150 magnification, the complex is a rough surface of the spherical It can be confirmed that it is a particle. In addition, (b) of FIG. 2 is a 20 times magnification (3,000 magnification) of (a), wherein the modified amphoteric graphene is coated with polymethylmethacrylate to form a shell, and (b) It can be confirmed that it has a form in which some peeled off as indicated in the figure.
표 3
중합률(%) 입도 (μm)
실시예 1 86.4 226.1
실시예 2 90.8 168.1
실시예 3 94.4 165.6
실시예 4 87.4 129.9
실시예 5 96.6 107.8
실시예 6 93.8 56.9
TABLE 3
% Polymerization Particle size (μm)
Example 1 86.4 226.1
Example 2 90.8 168.1
Example 3 94.4 165.6
Example 4 87.4 129.9
Example 5 96.6 107.8
Example 6 93.8 56.9
또한, 상기 표 3에 나타낸 바와 같이, 본 발명에 따른 그래핀-폴리메틸메타크릴레이트 복합체는 첨가되는 양쪽성 그래핀의 혼합량에 상관없이 약 85% 이상의 우수한 수율로 중합반응이 수행되며, 입도는 중합 반응 시 메틸메타크릴레이트와 혼합되는 양쪽성 그래핀의 혼합량이 증가함에 따라 감소하는 것을 알 수 있다. 이는 분산 안정제의 양이 증가함에 따라 제조되는 고분자의 입도가 감소하는 분산중합, 유화중합 또는 현탁중합의 반응경향과 일치하는 것이다. 즉, 본 발명에 따른 그래핀-고분자 복합체의 제조방법은 개질된 양쪽성 그래핀이 고분자를 코팅하여 쉘을 이룸과 동시에, 중합반응에서 "피커링 안정화제"의 역할을 수행하는 것을 알 수 있다.In addition, as shown in Table 3, the graphene-polymethyl methacrylate composite according to the present invention, the polymerization reaction is carried out in an excellent yield of about 85% or more irrespective of the mixed amount of the amphoteric graphene added, the particle size is It can be seen that the polymerization decreases with increasing amount of the amphoteric graphene mixed with methyl methacrylate. This coincides with the reaction tendency of dispersion polymerization, emulsion polymerization or suspension polymerization in which the particle size of the prepared polymer decreases as the amount of dispersion stabilizer increases. That is, in the method for producing a graphene-polymer composite according to the present invention, it can be seen that the modified amphoteric graphene coats a polymer to form a shell and at the same time plays a role of "pickering stabilizer" in the polymerization reaction.
이로부터, 본 발명에 따른 그래핀-고분자 복합체의 제조방법은 개질된 양쪽성 그래핀을 사용하여 복합체를 사용하여 제조함으로써, 별도의 안정제를 사용하지 않고도 안정적으로 중합반응을 수행할 수 있으며, 이렇게 제조되는 복합체는 표면에 개질된 양쪽성 그래핀이 코팅되어 쉘을 이루는 고분자 입자의 형태를 갖는 것을 알 수 있다.From this, the production method of the graphene-polymer composite according to the present invention by using a composite using a modified amphoteric graphene, it is possible to perform a polymerization reaction stably without using a separate stabilizer, so It can be seen that the composite prepared has the form of polymer particles forming a shell by coating the amphoteric graphene modified on the surface.
실험예 2. 그래핀-고분자 복합체의 제조방법에 따른 전기적 물성 평가Experimental Example 2. Evaluation of electrical properties according to the preparation method of the graphene-polymer composite
본 발명에 따른 그래핀-고분자 복합체의 제조방법에 따른 전기적 물성을 평가하기 위하여 하기와 같은 실험을 수행하였다.In order to evaluate the electrical properties according to the method for producing a graphene-polymer composite according to the present invention, the following experiment was performed.
본 발명에 따른 실시예 1에서 제조된 그래핀-폴리메틸메타크릴레이트 복합체 입자를 130℃, 10 MPa의 압력 조건으로 압축 성형하여 시트 형태(3.0 cm Χ 3.0 cm Χ 100 μm의)의 시편을 제조하였다. 또한, 실시예 2 내지 실시예 6, 및 비교예 1 내지 비교예 7에서 제조된 그래핀- 폴리메틸메타크릴레이트 복합체 입자를 상기와 동일한 방법으로 압축 성형하여 시편을 제조하였다. 제조된 시편에 대하여 4 탐침법(four-point probe method)을 이용한 전기 전도도를 측정하였으며, 그 결과를 하기 표 4에 나타내었다.Graphene-polymethyl methacrylate composite particles prepared in Example 1 according to the present invention by compression molding under a pressure condition of 130 ℃, 10 MPa to prepare a specimen in the form of a sheet (3.0 cm 3.0 cm × 100 μm) It was. In addition, the graphene-polymethyl methacrylate composite particles prepared in Examples 2 to 6, and Comparative Examples 1 to 7 were compression molded in the same manner as above to prepare a specimen. The electrical conductivity of the prepared specimens was measured using a four-point probe method, and the results are shown in Table 4 below.
표 4
그래핀 혼합량 (phr) 전기 전도도 (S/cm)
실시예 1 0.3 5.39 Ｘ 10-5
실시예 2 0.5 2.24 Ｘ 10-4
실시예 3 1.0 8.43 Ｘ 10-4
실시예 4 2.0 1.14 Ｘ 10-2
실시예 5 3.0 4.10 Ｘ 10-2
실시예 6 5.0 1.57 Ｘ 10-1
비교예 1 0 1.75 Ｘ 10-12
비교예 2 0.3 2.10 Ｘ 10-12
비교예 3 0.5 1.87 Ｘ 10-12
비교예 4 1.0 2.69 Ｘ 10-12
비교예 5 2.0 2.79 Ｘ 10-12
비교예 6 3.0 3.79 Ｘ 10-8
비교예 7 5.0 1.00 Ｘ 10-6
Table 4
Graphene Blending Amount (phr) Electrical conductivity (S / cm)
Example 1 0.3 5.39 Ｘ 10 -5
Example 2 0.5 2.24 Ｘ 10 -4
Example 3 1.0 8.43 Ｘ 10 -4
Example 4 2.0 1.14 Ｘ 10 -2
Example 5 3.0 4.10 Ｘ 10 -2
Example 6 5.0 1.57 Ｘ 10 -1
Comparative Example 1 0 1.75 Ｘ 10 -12
Comparative Example 2 0.3 2.10 Ｘ 10 -12
Comparative Example 3 0.5 1.87 Ｘ 10 -12
Comparative Example 4 1.0 2.69 Ｘ 10 -12
Comparative Example 5 2.0 2.79 Ｘ 10 -12
Comparative Example 6 3.0 3.79 Ｘ 10 -8
Comparative Example 7 5.0 1.00 Ｘ 10 -6
표 4에 나타난 바와 같이, 본 발명에 따른 그래핀-고분자 복합체는 우수한 전기 전도성을 나타내는 것을 알 수 있다.As shown in Table 4, it can be seen that the graphene-polymer composite according to the present invention exhibits excellent electrical conductivity.
보다 구체적으로, 비교예 1에서 제조된 순수한 폴리메틸메타크릴레이트의 전기 전도도는 절연성으로, 전기 전도도가 1.75 Ｘ 10-12 S/cm인 것으로 확인되었다. 그러나, 본 발명에 따른 실시예 1 내지 실시예 6에서 제조된 복합체는 폴리메틸메타크릴레이트 제조 시, 개질된 양쪽성 그래핀을 첨가하여 폴리메틸메타크릴레이트 표면에 그래핀 쉘을 형성함으로써, 전기 전도도가 3.1 Ｘ 107 내지 9.0 Ｘ 1010 배 향상되는 것을 확인할 수 있다. 또한, 비교예 2 내지 비교예 7에서 폴리아크릴레이트와 양쪽성 그래핀을 혼합하여 제조되는 복합체의 경우, 1.2 내지 5.7 Ｘ 105 배 향상되는 것을 확인할 수 있다. 즉, 단량체와 양쪽성 그래핀 혼합물의 중합을 수행하여 복합체를 제조하는 경우(실시예의 경우), 중합된 폴리아크릴레이트와 양쪽성 그래핀을 혼합하여 복합체를 제조하는 경우(비교예의 경우)와 대비하여 전기 전도도가 약 5.4 Ｘ 10 내지 7.5 Ｘ 1010 배 더 높은 것을 알 수 있다.More specifically, the electrical conductivity of a pure poly (methyl methacrylate) prepared in Comparative Example 1 is an insulating, electrical conductivity was found to be 1.75 X 10 -12 S / cm. However, the composites prepared in Examples 1 to 6 according to the present invention are prepared by adding modified amphoteric graphene to form a graphene shell on the surface of polymethylmethacrylate when polymethylmethacrylate is prepared. It can be seen that the conductivity is improved by 3.1 × 10 7 to 9.0 × 10 10 times. In addition, in the case of the composite prepared by mixing the polyacrylate and the amphoteric graphene in Comparative Examples 2 to 7, it can be seen that the 1.2 to 5.7 × 10 5 times improved. That is, in the case of preparing a composite by performing polymerization of the monomer and amphoteric graphene mixture (in the case of the embodiment), compared to the case of preparing the composite by mixing the polymerized polyacrylate and the amphoteric graphene (in the comparative example). It can be seen that the electrical conductivity is about 5.4 Ｘ 10 to 7.5 Ｘ 10 10 times higher.
이로부터, 본 발명에 따른 그래핀-고분자 복합체는 단량체와 양쪽성 그래핀의 혼합물로부터 중합을 수행함으로써 중합된 고분자와 양쪽성 그래핀을 혼합하여 제조되는 복합체와 대비하여 현저히 우수한 전기 전도성을 구현할 수 있음을 알 수 있다.From this, the graphene-polymer composite according to the present invention can achieve a significantly superior electrical conductivity compared to the composite prepared by mixing the polymerized polymer and amphoteric graphene by performing polymerization from a mixture of monomer and amphoteric graphene. It can be seen that.
따라서, 본 발명에 따른 그래핀-고분자 복합체의 제조방법은, 그래핀 탄소 원자 100개에 대하여 0.2≤n≤60개의 친수성기가 표면에 도입된 그래핀을 사용함으로써, 별도의 계면안정제, 분산안정제 등의 사용하지 않고 그래핀의 분산력을 향상시킬 있을 뿐만 아니라, 그래핀 표면에 비편재화된 탄소-탄소 이중결합의 변형을 최소화할 수 있다. 이에 따라, 제조되는 그래핀-고분자 복합체는 소량의 그래핀을 함유하여도 전기 전도성이 우수하므로, 전기 전도성이 요구되는 다양한 분야에서 유용하게 사용될 수 있다.Therefore, in the method for preparing a graphene-polymer composite according to the present invention, by using graphene having 0.2 ≦ n ≦ 60 hydrophilic groups introduced on the surface of 100 graphene carbon atoms, a separate interfacial stabilizer, dispersion stabilizer, etc. In addition to improving the dispersibility of graphene without the use of, it is possible to minimize the deformation of the carbon-carbon double bonds delocalized on the graphene surface. Accordingly, the graphene-polymer composite prepared is excellent in electrical conductivity even if it contains a small amount of graphene, it can be usefully used in various fields that require electrical conductivity.
본 발명에 따른 그래핀-고분자 복합체는, 그래핀 고유의 물성저하가 적어 소량의 그래핀을 함유하여도 우수한 전기 전도성이 구현되므로, 전기 전도성이 요구되는 다양한 분야에서 유용하게 사용될 수 있다.The graphene-polymer composite according to the present invention has a low physical property inherent in graphene, so that excellent electrical conductivity is realized even when a small amount of graphene is contained, and thus may be usefully used in various fields requiring electrical conductivity.

Claims (13)

  1. 고분자 코어; 및Polymer cores; And
    양쪽성 그래핀(graphene)으로 구성되는 쉘을 포함하고,A shell composed of amphoteric graphene,
    상기 양쪽성 그래핀은 그래핀 탄소 원자 100개에 대하여 하기 수학식 1을 만족하는 n개의 친수성기를 표면에 포함하는 그래핀-고분자 복합체:The amphoteric graphene is a graphene-polymer composite including n hydrophilic groups satisfying the following Equation 1 for 100 graphene carbon atoms on its surface:
    [수학식 1][Equation 1]
    0.2 ≤ n ≤ 60.0.2 ≦ n ≦ 60.
  2. 제1항에 있어서,The method of claim 1,
    친수성기는, COO-M+ 및 SO3 -M+ 중 어느 하나 이상을 포함하고,The hydrophilic group includes any one or more of COO - M + and SO 3 - M + ,
    상기 M은 H, Li, Na, K, Rb, Cs 또는 4차 아민인 그래핀-고분자 복합체.Wherein M is H, Li, Na, K, Rb, Cs or quaternary amine graphene-polymer composite.
  3. 제1항에 있어서,The method of claim 1,
    양쪽성 그래핀의 함량은, 고분자 코어에 대하여 0.1 내지 10 phr인 그래핀-고분자 복합체.Amphoteric graphene content, the graphene-polymer composite is 0.1 to 10 phr relative to the polymer core.
  4. 제1항에 있어서,The method of claim 1,
    고분자 코어에 대한 양쪽성 그래핀의 함량이 1 phr인 그래핀-고분자 복합체에 대하여,For the graphene-polymer composite having an amphoteric graphene content of 1 phr for the polymer core,
    전기 전도도(L) 평가 시, 하기 수학식 2를 만족하는 그래핀-고분자 복합체:When evaluating the electrical conductivity (L), the graphene-polymer composite that satisfies Equation 2 below:
    [수학식 2][Equation 2]
    L ≥ 1.0 × 10-8 L ≥ 1.0 × 10 -8
    여기서, 상기 전기 전도도(L)의 단위는 S/cm이다.Here, the unit of the electrical conductivity (L) is S / cm.
  5. 제1항에 있어서,The method of claim 1,
    고분자 코어는, 메틸아크릴레이트(methylacrylate, MA), 에틸아크릴레이트(ethylacrylate, EA), 부틸아크릴레이트(butylacrylate, BA), 메틸메타크릴레이트(methylmetacrylate, MMA), 에틸메타크릴레이트(ethylmetacrylate, EMA), 부틸메타크릴레이트(butylmetacrylate, BMA), 2-에틸헥실메타크릴레이트(2-ethylhexylmetacrylate, EHMA), 글리시딜메타크릴레이트(glycidyl methacrylate, GMA), 스티렌(styrene) 알파-메틸스티렌(α-methylstyrene), 염화비닐(vinylchloride), 염화비닐리덴(vinylidene chloride), 에틸렌(ethylene) 및 프로필렌(propylene)으로 이루어진 군으로부터 선택되는 1종 이상의 비닐계 단량체가 중합된 것을 특징으로 하는 그래핀-고분자 복합체.The polymer core is methyl acrylate (MA), ethyl acrylate (EA), butyl acrylate (BA), methyl methacrylate (MMA), ethyl methacrylate (ethyl methacrylate, EMA). Butyl methacrylate (BMA), 2-ethylhexyl methacrylate (EHMA), glycidyl methacrylate (GMA), styrene alpha-methylstyrene (α- Graphene-polymer composite, characterized in that at least one vinyl monomer selected from the group consisting of methylstyrene, vinyl chloride, vinylidene chloride, ethylene and propylene is polymerized .
  6. 비닐계 단량체, 개시제 및 양쪽성 그래핀을 포함하는 혼합물의 중합반응을 수행하여 그래핀-고분자 복합체를 제조하는 그래핀-고분자 복합체의 제조방법.Method for producing a graphene-polymer composite to produce a graphene-polymer composite by carrying out a polymerization reaction of a mixture comprising a vinyl monomer, an initiator and amphoteric graphene.
  7. 제6항에 있어서,The method of claim 6,
    양쪽성 그래핀은, 그래핀 탄소 원자 100개에 대하여 하기 수학식 1을 만족하는 n개의 친수성기를 표면에 포함하는 그래핀-고분자 복합체의 제조방법:Amphoteric graphene, a method for producing a graphene-polymer composite containing n hydrophilic groups satisfying the following formula 1 for 100 graphene carbon atoms on the surface:
    [수학식 1][Equation 1]
    0.2 ≤ n ≤ 60.0.2 ≦ n ≦ 60.
  8. 제6항에 있어서,The method of claim 6,
    양쪽성 그래핀은, 친수성기를 함유하는 화합물로 표면 개질된 것을 특징으로 하는 그래핀-고분자 복합체의 제조방법.Amphoteric graphene is a method for producing a graphene-polymer composite, characterized in that the surface modified with a compound containing a hydrophilic group.
  9. 제8항에 있어서,The method of claim 8,
    친수성기를 함유하는 화합물은,Compound containing a hydrophilic group,
    COO-M+ 및 SO3 -M+ 중 어느 하나 이상의 친수성기; 및Hydrophilic groups of any one or more of COO - M + and SO 3 - M + ; And
    하나의 아민기를 포함하고,Contains one amine group,
    상기 친수성기의 M은 H, Li, Na, K, Rb, Cs 또는 4차 아민인 그래핀-고분자 복합체의 제조방법.M of the hydrophilic group is H, Li, Na, K, Rb, Cs or quaternary amine method for producing a graphene-polymer composite.
  10. 제6항에 있어서,The method of claim 6,
    중합반응은, 분산중합, 유화중합 또는 현탁중합인 것을 특징으로 하는 그래핀-고분자 복합체의 제조방법.The polymerization reaction is a method for producing a graphene-polymer composite, characterized in that the dispersion polymerization, emulsion polymerization or suspension polymerization.
  11. 제6항에 있어서,The method of claim 6,
    양쪽성 그래핀의 혼합량은, 비닐계 단량체에 대하여 0.1 내지 10 phr인 것을 특징으로 하는 그래핀-고분자 복합체의 제조방법.Mixing amount of the amphoteric graphene, the production method of the graphene-polymer composite, characterized in that 0.1 to 10 phr relative to the vinyl monomer.
  12. 제6항에 있어서,The method of claim 6,
    그래핀-고분자 복합체의 크기는, 0.01 내지 10,000 μm인 것을 특징으로 하는 그래핀-고분자 복합체의 제조방법.The size of the graphene-polymer composite, the method of producing a graphene-polymer composite, characterized in that 0.01 to 10,000 μm.
  13. 제6항에 있어서,The method of claim 6,
    비닐계 단량체는 메틸아크릴레이트(methylacrylate, MA), 에틸아크릴레이트(ethylacrylate, EA), 부틸아크릴레이트(butylacrylate, BA), 메틸메타크릴레이트(methylmetacrylate, MMA), 에틸메타크릴레이트(ethylmetacrylate, EMA), 부틸메타크릴레이트(butylmetacrylate, BMA), 2-에틸헥실메타크릴레이트(2-ethylhexylmetacrylate, EHMA), 글리시딜메타크릴레이트(glycidyl methacrylate, GMA), 스티렌(styrene) 알파-메틸스티렌(α-methylstyrene), 염화비닐(vinylchloride), 염화비닐리덴(vinylidene chloride), 에틸렌(ethylene) 및 프로필렌(propylene)으로 이루어진 군으로부터 선택되는 1종 이상인 그래핀-고분자 복합체의 제조방법.Vinyl monomers include methyl acrylate (MA), ethyl acrylate (EA), butyl acrylate (BA), methyl methacrylate (MMA), and ethyl methacrylate (ethyl methacrylate, EMA). Butyl methacrylate (BMA), 2-ethylhexyl methacrylate (EHMA), glycidyl methacrylate (GMA), styrene alpha-methylstyrene (α- Method for producing a graphene-polymer composite of at least one selected from the group consisting of methylstyrene, vinyl chloride, vinylidene chloride, ethylene and propylene.
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