KR20190122961A - Polymer fluororesin-carbon powder, polymer fluororesin-carbon composite using multi-structure carbon composite and manufacturing method the same - Google Patents

Abstract

The present invention relates to a polymer fluorine resin-carbon powder using a carbon composite material having a multi structure, and a manufacturing method thereof. The manufacturing method comprises the steps of: fluorine-treating a 2D graphite and pretreating one-dimensional carbon nanotubes; mixing the 2D graphite and one-dimensional carbon nanotubes to form a carbon composite material; and mixing the carbon composite material with zero-dimensional fluorine resin particles to form a polymer fluorine resin-carbon powder. The 2D graphite contains a fluorine functional group on a surface thereof to be hydrophilic bonded to the zero-dimensional fluorine resin particles, and a high shear stress is applied to the 2D graphite and the zero-dimensional fluorine resin particles and the zero-dimensional fluorine resin particles are uniformly distributed on a surface of the 2D graphite by means of an interfacial interaction. Accordingly, the present invention forms a carbon composite material, in which a 2D graphite fluorine fluorinated to provide a polarity on a surface thereof and one-dimensional carbon nanotubes are uniformly distributed by a hydrophobic bond, and evenly mixes the carbon composite material with zero-dimensional fluorine resin particles by the interfacial interaction to obtain a polymer fluorine resin-carbon powder capable of improving electric conductivity and strength. In case of manufacturing a composite by using the polymer fluorine resin-carbon powder manufactured thereby, the composite is molded by using hot forming device to be applicable in electronic devices such as fuel cell separating plates, heat radiating elements, EMI shielding elements and the like.

Description

Polymer fluororesin-carbon powder, polymer fluororesin-carbon composite using multi-structure carbon composite and manufacturing method the same}

The present invention relates to a polymer fluorocarbon-carbon powder, a polymer fluorocarbon-carbon composite, and a method of manufacturing the same using a carbon composite material having a multi-structure, and more particularly to fluorine-treated two-dimensional graphite And to form a carbon composite material uniformly dispersed by hydrophobic bonding of one-dimensional carbon nanotubes and uniformly mix the carbon composite material by interfacial interaction with the 0-dimensional fluororesin particles to increase electrical conductivity and strength. The present invention relates to a polymer fluorocarbon-carbon powder, a polymer fluorocarbon-carbon composite, and a manufacturing method using a carbon composite material having a multi-structure.

Graphite is a material made of carbon, and is a carbon allotrope and forms a plate crystal belonging to a hexagonal system. Such graphite is excellent in mechanical strength, chemical stability, thermal conductivity, electrical conductivity, etc., and can be mass-produced artificially, and thus, various applications are expected in modern industrial fields such as fuel cells, heat radiating devices, EMI shielding devices, and the like. In the case of such graphite, the graphite crystal shows a crystal structure of a basal plane that is a plane perpendicular to the C-axis direction and an edge plane that is parallel to the C-axis direction. Such graphite corresponds to a plate-shaped two-dimensional material. Due to the difference in the specific surface area, the polymer has a stronger binding force to the base surface than to the edge surface of graphite.

Therefore, in the conventional case, carbon black, which is a 0-dimensional material, is mainly used as a carbon material, or carbon nanotubes, which are linear one-dimensional materials, are mixed with a polymer resin to make a polymer-carbon material powder in which a carbon material and a polymer resin are mixed. It was. In addition, a technique of improving dispersibility is mainly applied by mixing carbon materials dispersed in nano size for uniform mixing with polymer resin. However, even when the carbon material and the polymer resin are mixed through these conventional techniques, there is a limit in improving the strength of the carbon material-polymer resin mixture, and this limitation is applicable to a field requiring a high-strength carbon material-polymer resin mixture. There was a difficult problem.

Representative technical fields using such a high-conductivity and high-strength separator is the fuel cell field and heat dissipation parts. Proton-exchange membrane fuel cell (PEMFC) based on hydrogen ion conductive polymer electrolyte membrane is an energy conversion system with high energy efficiency and low emission of air pollution. In particular, unlike fossil fuels, the use of hydrogen and methanol as a fuel is almost permanent, and thus research is being conducted with high interest as an alternative energy source. The formed hydrogen ions move to the cathode through the hydrogen-ion conductive polymer electrolyte membrane like hydrogen ion transfer, and the electrons moved through the external circuit and the air supplied to the cathode meet with the oxygen, thereby reducing water and Electric energy is generated heat.

<Scheme>

_{Anode: H 2 → 2H + +} 2e -

_{Cathode: 1 / 2O 2 + 2H} + + 2e - → H 2 O

Overall: H ₂ + 1 / 2O ₂ → H ₂ O

Such a fuel cell is a gas non-permeable layer and a gas-permeable permeation layer including a graphite conductive material and a binder having a particle diameter of 0.01 to 50 μm, as in the prior art 'Korean Patent Registration Patent No. 10-0805989, Fuel Cell Separator and Stack for Fuel Cell Using the Same' It is formed to have a flow path pattern on one or both sides of the layer, and consists of a technique including a gas permeable layer comprising a graphite conductive material and a binder. However, when manufacturing a separator plate by compressing only graphite having a large size as in the prior art, the resistance to phosphoric acid is excellent but the strength is lowered. As a result, when the thickness of the separator is reduced, the strength and the thermal conductivity in the vertical direction are not good, thereby reducing energy efficiency using waste heat. In addition, when the separator is manufactured using a small size of graphite, the graphite is easily peeled off and easily dispersed in the polymer resin, so that the strength is improved. However, since the connection between the graphite particles is not good, the electrical resistivity increases. have.

In particular, FEP (fluorinated ethylene propylene copolymer), which is mainly used in separators for fuel cells, is mixed with a carbon material and forms a separator through hot forming. Such a polymer resin does not have a strong chemical bonding force with a carbon material and thus has high strength. There is a disadvantage that the electrolyte is leaked when the fuel cell stack is fastened. In addition, the higher the resistance, the lower the efficiency of the fuel cell stack due to the transportation of fuel.

In the case of the polymer used as a separator material for high temperature PEMFC, strong chemical resistance to reactants and phosphoric acid is required, which affects the durability and reliability of the fuel cell stack.

Korea Patent Office Registered Patent No. 10-0805989

Accordingly, an object of the present invention is to form a carbon composite material in which fluorinated two-dimensional graphite and one-dimensional carbon nanotubes are uniformly dispersed by hydrophobic bonding to give polarity to the surface, and the carbon composite material is a 0-dimensional fluorocarbon resin. The present invention provides a polymer fluorocarbon-carbon powder, a polymeric fluorocarbon-carbon composite using a carbon composite material having a multi-structure that can be uniformly mixed by interfacial interaction with particles to increase electrical conductivity and strength, and a manufacturing method thereof. .

The above object is to fluorine two-dimensional graphite, and to pre-treat one-dimensional carbon nanotubes; Forming a carbon composite material by mixing the two-dimensional graphite and one-dimensional carbon nanotubes; Mixing the carbon composite material with 0-D fluororesin particles to form a polymer fluororesin-carbon powder, wherein the 2D graphite is hydrophilically bonded to the 0-D fluororesin particles by including a fluorine functional group on a surface thereof, The two-dimensional graphite and the 0-dimensional fluororesin particles are subjected to high shear stress, so that the 0-dimensional fluororesin particles are evenly distributed on the surface of the two-dimensional graphite by interfacial interaction. It is achieved by a method for producing a polymer fluorocarbon-carbon powder or a composite using a carbon composite material having a multi-structure.

Here, the step of forming the polymer fluorocarbon-carbon powder, by milling the 0-dimensional fluorocarbon resin particles through the formation of granule-shaped granules (granule) of the surface partly due to high shear stress (high shear stress) The specific surface area of the 0-dimensional fluororesin particles increases, the 2D graphite is milled, peeled off into a plate shape, and the particle distribution is increased, thereby interfacing with the 0-dimensional fluororesin particles by interfacial interaction. It is preferable that the dimensional fluororesin particles are evenly distributed on the two-dimensional graphite surface, and the milling may include a ball mill, a shaker mill, a vibratory mill, and a planetary mill. ) Or an attritor mill is preferably used.

The pretreatment of the one-dimensional carbon nanotubes may include dispersing the one-dimensional carbon nanotubes in an organic solvent and dispersing them using an ultrasonic irradiator, pulverizing them through lyophilization, and fluorinating the two-dimensional graphite. The oxygen fluorine (oxyfluorination) is treated with a fluorine functional group and an oxygen functional group to the surface of the two-dimensional graphite is preferably the two-dimensional graphite has a hydrophilic surface.

The oxygen-containing fluorination is preferably treated for 10 to 60 minutes at a pressure of 0.01 to 1.0 bar in a reactor using a mixed gas consisting of fluorine gas and oxygen gas.

The above object is also provided with 0-dimensional fluororesin particles; One-dimensional carbon nanotubes in a debundling state; The surface includes two-dimensional graphite modified with a fluorine functional group, the two-dimensional graphite includes a fluorine functional group on the surface is hydrophilically bonded to the 0-dimensional fluororesin particles, the two-dimensional graphite and the 0-dimensional fluororesin particles are high Polymeric fluorine resin using a carbon composite material having a multi-structure, characterized in that the 0-dimensional fluororesin particles are evenly distributed on the surface of the two-dimensional graphite by interfacial interaction by applying a high shear stress It is also achieved by carbon powders or composites.

According to the above-described configuration of the present invention, in order to impart polarity to the surface, fluorine-treated two-dimensional graphite and one-dimensional carbon nanotubes are uniformly dispersed by hydrophobic bonding to form a carbon composite material, and the carbon composite material is 0-dimensional. It is possible to obtain a polymer fluorocarbon-carbon powder which can be uniformly mixed by interfacial interaction with the fluororesin particles to increase the electrical conductivity and strength.

The polymer fluorocarbon-carbon powder thus prepared is used to form a polymer carbon composite using a hot forming apparatus, and thus it may be applied to electronic devices such as fuel cell separators, heat radiating elements, and EMI shielding elements.

1 is a view of a polymer fluorocarbon-carbon powder or composite using a carbon composite material according to an embodiment of the present invention,
2 is a flow chart of a method for preparing a polymer fluorocarbon-carbon powder or composite,
3 and 4 are Raman spectra before and after oxygenated fluorination treatment of graphite and carbon nanotubes,
5 is a SEM photograph of a carbon material mixed with graphite and carbon nanotubes,
6 is a SEM photograph after milling of graphite and fluororesin particles,
7 is a SEM photograph after milling of graphite, carbon nanotubes, and fluororesin particles;
8 and 9 show the results of confirming the content of the substituted fluorine through EDX analysis (Bruker, XFlash 410-M).

Hereinafter, a polymer fluorocarbon-carbon powder, a polymer fluorocarbon-carbon composite, and a method of manufacturing the same using a carbon composite material having a multi-structure according to an embodiment of the present invention will be described in detail.

In the case of using two-dimensional graphite as a carbon material to prepare a polymer fluorocarbon-carbon powder or a composite, there is a limit in increasing the electrical conductivity, and it is not preferable to be applied to a separator alone because it is not excellent in strength. In addition, in the case of the one-dimensional carbon nanotubes are prone to agglomeration, it is difficult to commercialize them because they are not excellent in dispersibility when mixed with fluorine resin. In order to solve the above problems, the polymer fluorocarbon-carbon powder or composite of the present invention is mixed with the fluorocarbon resin using a carbon composite material mixed with two-dimensional graphite and one-dimensional carbon nanotubes.

Polymeric fluorocarbon-carbon powder or composite according to the present invention, as shown in Figure 1, 0-dimensional fluororesin particles; One-dimensional carbon nanotubes in a debundling state; The surface includes two-dimensional graphite modified with a fluorine functional group, and the two-dimensional graphite includes a fluorine functional group on the surface to be hydrophilically coupled with the 0-dimensional fluororesin particles, and the 2-dimensional graphite and the 0-dimensional fluororesin particles have a high shear stress. Shear stress is applied to make the 0-D fluororesin particles evenly distributed on the 2-D graphite surface by interfacial interaction. Here, the composite is formed through the polymer fluorocarbon-carbon powder and means a product which is applicable to a separator or a heat sink.

In the fluorine-treated graphite-fluorine resin powder or composite manufacturing method, as shown in FIG. 2, first, two-dimensional graphite is fluorinated (S1a).

Graphite is a two-dimensional carbon material having a size of 400 µm or more, and is made of a plate having a surface. If the size of the graphite is less than 400㎛, the bond strength with the 0-D fluororesin particles decreases due to the difference in surface energy due to the reduction of the hydrophobic basal plane of the graphite, and the 0-D fluororesin particles cannot be stably bonded to the surface. There is this. In other words, the hydrophobic base surface becomes a hydrophilic surface through fluorination in a later step. Since the more hydrophilic surface, the bonding force with the fluorine resin particles increases, the size of graphite is preferably 400 μm or more. Such graphite can be used without limitation in the kind of graphite, such as artificial graphite, expanded graphite, natural graphite.

In order to impart polarity to the graphite surface, two-dimensional graphite is fluorinated. In this case, fluorine treatment refers to oxyfluorination treatment, which imparts polarity to the graphite surface and enhances physical affinity by acting as a compatibilization agent with the fluorine resin.

Since graphite has a stack shape, oxygen fluorinated fluorine is treated on the edge plane parallel to the C-axis direction instead of the basal plane that is perpendicular to the C-axis when oxyfluorinated fluorination is performed. Fluorine is substituted. 3 shows Raman spectra before and after oxygenated fluorination of graphite. When the oxygen-containing fluorinated graphite treatment, the edge side is fluorine-substituted, so there is almost no increase in D / G ratio and 2D / G ratio, and the increase is insignificant. In addition, a large 2D / G ratio means that graphite having excellent crystallinity is used.

Oxygen-containing fluorination is treated for 10 to 60 minutes at a pressure of 0.01 to 1.0 bar in a reactor using a mixed gas consisting of fluorine gas and oxygen gas. Through this, graphite substituted with fluorine can be obtained. When the oxygen-oxyfluorinated graphite is treated as described above, a fluorine functional group and a small amount of oxygen functional groups are bonded to the graphite on the hydrophobic surface to have a hydrophilic surface, thereby improving the binding strength with the fluorine resin powder.

The fluorine gas is nitrogen trifluoride (NF ₃ , nitron fluorine three), carbon tetrafluoride (CF ₄ , tetrafluoromethane), trifluoromethane (CHF ₃ , trifluoromethane), trifluorofluorocarbons (C ₃ F ₈ , octafluoropropane) and octafluoride It is selected from the group consisting of tetracarbon (C ₄ F ₈ , octafluorocyclobutane) and mixtures thereof, and the mixing ratio of fluorine gas and oxygen gas is used by mixing in a volume ratio of fluorine gas: oxygen gas = 5 to 95: 95 to 5. desirable. Oxygen-fluorination treatment of the graphite through this step is because the hydrophobic surface of the graphite is surface-modified by the hydrophilic functional group, it is then easily mixed with the fluororesin particles.

In the case of 2D carbon material, not only graphite but also graphene may be used, but in the case of graphene, the method of manufacturing graphene is added to increase the manufacturing process and cost, and defects may reduce electrical conductivity. . Graphene is generally obtained by generating graphite defects through strong acid treatment using Hummer's method. In addition, a method of reducing graphene oxide after production using a reducing agent has been used. Therefore, since graphene is used, the step of the process increases, and thus, the oxygen fluorination treatment is directly performed on the surface of the graphite using graphite rather than graphene, thereby improving electrical conductivity and simplifying the process.

One-dimensional carbon nanotubes are pretreated (S1b).

In the step S1a, carbon nanotubes, which are one-dimensional carbon materials to be mixed with the oxygen-containing fluorinated graphite, are pretreated. Since carbon nanotubes are formed in a long one-dimensional wire shape in the longitudinal direction, strength and electrical conductivity can be increased by connecting dispersed oxygen-oxyfluorinated graphite. In the case of graphite, since the two-dimensional shape, the graphite alone forms an excellent conductive path, but when the one-dimensional carbon nanotubes are mixed with the graphite, an excellent conductive path may be formed to increase electrical conductivity. Unlike graphite, such carbon nanotubes do not undergo oxygen fluorination.

In the case of carbon nanotubes, they may exist in a bundling state. In order to easily mix them with the graphite, the carbon nanotubes must be dispersed in a debundling state. Therefore, pretreatment is performed so that the carbon nanotubes are in a dispersed state. In the pretreatment of the one-dimensional carbon nanotubes, the carbon nanotubes are introduced into an organic solvent, dispersed using an ultrasonic irradiator, and the carbon nanotubes are powdered through lyophilization.

Such carbon nanotubes are single-walled carbon nanotubes (SWCNTs), double-walled carbon nanotubes (DWCNTs) or multi-walled carbon nanotubes (MWCNTs). However, it is most preferable to apply single wall carbon nanotubes having excellent crystallinity and good electrical conductivity.

In the case of graphite, since the purity is generally good, it can be directly applied to the preparation of powder or composite, but in the case of carbon nanotubes, the purity is not good, and in some cases, to remove some of the mixed carbon from the prepared carbon nanotubes. Carbon nanotubes can be heat treated. Heat treatment conditions are heated at 500 to 1000 ℃ for 1 hour or more under an air atmosphere, it is possible to obtain a one-dimensional carbon nanotubes from which amorphous carbon is removed.

In addition, unlike graphite, carbon nanotubes are preferably not subjected to oxygen fluorination. Figure 4 shows the Raman spectrum before and after oxygenated fluorination treatment of carbon nanotubes, it can be seen that when the oxygen fluorination treatment of carbon nanotubes, the D / G is significantly increased, which is the oxygen fluorination treatment of carbon nanotubes If so, more defects occur than graphite, which means that the electrical conductivity is reduced. In the case of carbon nanotubes, since the specific surface area is larger than graphite due to the bundle structure, the amount of fluorine-substituted is more than that of graphite, and defects tend to occur, thereby lowering the electrical conductivity. Therefore, it is preferable that the oxygen fluorination treatment proceeds only with graphite and not with carbon nanotubes.

Two-dimensional graphite and one-dimensional carbon nanotubes are mixed to form a carbon composite material (S2).

In the step S1a, the oxygen-containing fluorinated two-dimensional graphite is mixed with the pre-treated one-dimensional carbon nanotubes through the step S1b to form a carbon composite material. Oxygen-fluorinated graphite is hydrophobic by the edge plane parallel to the C-axis, and hydrophilic, and the basal plane perpendicular to the C-axis maintains hydrophobicity. . The hydrophobic bond is made by dispersing carbon nanotubes having a hydrophobic surface on the base surface of the graphite having such a hydrophobic surface. As a method of mixing two-dimensional graphite and one-dimensional carbon nanotubes to be evenly dispersed, it may be mixed by milling. The milling is preferably any one of a ball mill, a shaker mill, a vibratory mill, a planetary mill, or an attritor mill.

5 is a SEM photograph of a carbon material in which graphite and single-walled carbon nanotubes are mixed. When the carbon nanotubes dispersed through ultrasonic irradiation and lyophilization are mixed with graphite, they are well dispersed by hydrophobic bonds between the carbon materials. You can check it. In addition, the electrical conductivity may be improved by acting as the interconnection between the carbon nanotubes having a large aspect ratio between the graphite.

When carbon nanotubes are mixed with graphite to form a carbon material, the carbon nanotubes of the total carbon materials are preferably mixed at 1 wt% or less, and the remaining carbon is preferably made of graphite. When the carbon nanotubes exceed 1wt%, the density is low and the volume is large, whereby the content of the carbon nanotubes increases, thereby forming the aggregates of the carbon nanotubes. As a result, it is impossible to see the effect of improving the electrical conductivity through the addition of carbon nanotubes.

The carbon composite material is mixed with the fluororesin particles to form a polymer fluorocarbon-carbon powder or a composite (S3).

Through the step S2, the carbon composite material is evenly dispersed with the fluororesin particles to form a polymer fluorocarbon-carbon powder or composite. Since the oxygen-containing fluorinated two-dimensional graphite is present in the carbon composite material, the carbon composite material has excellent binding strength with the fluororesin particles, thereby forming a polymer fluorocarbon-carbon powder or a composite in a uniformly dispersed state.

In this case, the fluorine resin refers to very small particle-shaped particles having a size of 10 μm or less as 0-dimensional particles. When the particle size of the fluorine resin exceeds 10 μm, the fluorine resin particles are not bonded to the graphite surface due to the high density and weight, and the fluorine resin particles are agglomerated with each other to obtain a uniformly distributed graphite-fluorine resin powder or composite. none. The fluororesin particles are preferably made of polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), fluorinated ethylene propylene (FEP), and mixtures thereof.

The carbon composite material and the fluorine resin particles are mixed in a dry state in which no solvent is present. The fluororesin-carbon powders are mixed by milling the 1D and 2D carbon composite materials and the 0D fluororesin particles and then milled. Or form a complex. In the case of graphite, the surface is a hydrophilic state containing a fluorine functional group and a small number of oxygen functional groups, and since the fluorine resin particles contain fluorine, this is also a hydrophilic state. Therefore, the formed polymer fluorocarbon-carbon powder or composite is bonded in a state where fluororesin particles are evenly distributed on the graphite surface by interfacial interaction. In this case, as in the step S2, it is preferable to use any one of a ball mill, a shaker mill, a vibration mill, a planetary mill, or an attritor mill.

As shown in FIG. 6, when the 0-dimensional fluororesin particles are milled, there is no significant decrease in size, and due to the high shear stress during milling, there are granule-shaped particles having irregular surfaces in part. The specific surface area of the fluororesin particles is increased. In addition, when the two-dimensional graphite is milled, the graphite is peeled off, and the graphite is peeled into a plate, so that the particle distribution is large, but there is little change in size, which may be evenly distributed on the surface by interfacial interaction with the 0-dimensional fluororesin particles. .

6 and 7 are SEM images of ball milling after adding fluorinated ethylene propylene, which is one-dimensional carbon nanotubes, two-dimensional graphite, and zero-dimensional fluororesin particles, and the particles of 8 μm are uniformly dispersed on the graphite surface. In addition, it can be seen that graphite and carbon nanotubes are evenly dispersed with each other.

When the 0-dimensional fluororesin particles and the 2-dimensional graphite are milled, the 0-dimensional fluororesin particles may be evenly distributed on the surface of the graphite having a plate shape in two dimensions. If only 0-dimensional or 1-dimensional carbon materials are used, not 2D graphite, it is difficult to effectively wrap the fluororesin particles, so that powders or composites in which the fluororesins and carbon materials are evenly dispersed may not be obtained.

In addition, when the fluororesin particles are bonded to the graphite surface due to the interfacial interaction, the graphite may be contained in the polymer fluorocarbon-carbon powder or the composite in a high content. When the polymer and the carbon material are mixed in a general manner, as the content of the carbon material increases, the mixed state is not good, and the carbon material and the polymer are aggregated individually. However, as in the present invention, the polymer uses 0-dimensional fluorine resin and the carbon material uses plate-shaped two-dimensional graphite, and when mixed by milling, the fluororesin particles are uniformly distributed by interfacial interaction and hydrophilic functional groups on the graphite surface. Thus, a high molecular weight fluorocarbon-carbon powder or composite containing graphite is obtained.

The polymer fluorocarbon-carbon powder or composite is preferably 60 to 95 wt% of graphite and 5 to 40 wt% of fluororesin particles. When the graphite is less than 60wt% and the fluorine resin particles are more than 40wt%, the fluororesin particles may not be bonded to the graphite surface, and the fluororesin particles may aggregate together. In addition, when the graphite is more than 95wt% and the 0-dimensional fluorine resin particles are less than 5wt%, there is a problem that can not be applied to the actual product because the strength of the product produced using such a polymer fluorocarbon-carbon powder or composite is reduced. .

Hereinafter, embodiments of the present invention will be described in more detail.

Comparative Example 1

Graphite (Asbury, # 3763) having 500㎛ size, carbon material and fluorinated ethylene propylene fluororesin particles (particle size = 5㎛, FEP, 6322PZ, 3M) were mixed and ball milled for 6 hours to polymer fluorine resin -To form graphite powder. Table 1 shows the electrical conductivity and flexural strength of the polymer fluororesin-graphite powder according to the graphite content.

Graphite content (wt%) 20 40 60 80 Electrical conductivity
(S / cm) 0.003 0.159 6.131 636.943 Flexural Strength (MPa) 17.54 11.58 9.68 8.96

Here, the electrical resistivity was measured using a resistance measuring instrument (Mitsubishi Co., Ltd., model name: MCT-T610) according to ASTM D991 standard, and after the sample (50 × 50 × 2mm, width, length, thickness) was manufactured with an applied voltage of 10V, 10 points or more. Samples were measured and calculated as average values. In addition, the flexural strength is the flexural strength at the rate of 10mm / min for the sample (12.7 × 5.6 × 4.8mm, width, length, thickness) processed using the universal testing equipment (UTM, DA-WHA, model name: DEC-M200KC). Was measured and calculated as the average value after measuring five or more samples. As a result, as the content of graphite increases as shown in Table 1, the conductive path decreases, so that the electrical conductivity increases but the bending strength decreases.

Comparative Example 2

Graphite (Asbury, # 3763) having a size of 500 μm and carbon nanotube powder prepared by using a pretreatment process are each oxyfluorinated and then uniformly mixed to form a carbon material. Then, the carbon material and the fluorinated ethylene propylene fluororesin particles (particle size = 5 μm, FEP, 6322PZ, 3M) are mixed and ball milled for 6 hours to form a polymer fluorocarbon-carbon composite powder.

Comparative Example 3

Graphite (Asbury, # 3763) having a size of 500 μm and carbon nanotubes manufactured by using a pretreatment process are uniformly mixed. Next, the carbon material and the fluorinated ethylene propylene fluororesin particles (particle size = 5 μm, FEP, 6322PZ, 3M) were mixed and ball milled for 6 hours to form a polymer fluorocarbon-carbon powder.

<Example>

Graphite (Asbury, # 3763) having a size of 500 μm and carbon nanotubes (OCiSAL SWCNT) prepared by CVD (chemical vapor deposition) synthesis were prepared, respectively.

Graphite is fluorine-substituted using an oxyfluorination method using fluorination equipment. Oxygen-containing fluorine-containing treatment is to supply the fluorine gas injection rate of 0.01 bar / min for 10 minutes in the ratio of oxygen gas: fluorine gas = 8: 2 to obtain a graphite containing a fluorine functional group on the surface. As a result of confirming the fluorine-treated graphite content as shown in Figure 8 and 9 through the EDX analysis (Bruker, XFlash 410-M) the fluorine content is replaced with 1 to 4%. These results can also be confirmed through Table 2.

spectrum C O F S One 92.51 5.12 1.64 0.73 2 84.97 10.01 3.94 1.08 mean value 91.88 5.66 2.79 0.91

 In the case of carbon nanotubes, since they are present in the aggregated bundle state due to the strong van der Waals forces, the pretreatment process is performed to enable dispersion with graphite. First, carbon nanotubes are introduced into a polar dimethylformamide (DMF) or dimethyl sulfoxide (DMSO) organic solvent, and then the carbon nanotubes are dispersed in the organic solvent using sonication, followed by a lyophilizer for an organic solvent. , FDCF-12012) to powder the carbon nanotubes.

In the case of carbon nanotubes (OCiSAL SWCNT) manufactured by CVD (chemical vapor deposition) synthesis, about 15 wt% of amorphous carbon is present. In order to remove the amorphous carbon, the carbon nanotube powder is immersed in an aluminum boat, heated at a rate of 10 ° C./min under an air atmosphere, and heat treated at 550 ° C. for 90 minutes to remove the amorphous carbon.

The carbon nanotubes are mixed by milling to uniformly disperse the graphite in powder form to form a carbon composite material. In the case of milling, the ball milling is performed for 6 hours. If the ball milling is performed for more than 10 hours, defects occur in graphite and carbon nanotubes, which lowers the electrical conductivity. .

After carbonaceous carbon composite material and fluorinated ethylene propylene fluorine resin particles (particle size = 5㎛, FEP, 6322PZ, 3M) mixed with graphite and carbon nanotubes having a fluorinated surface were measured, ball milling was performed for 6 hours. In the case of ball milling, as in the carbon composite material forming step, the graphite and the carbon nanotubes are defective after 10 hours.

The graphite-fluorinated carbon composite material powder formed through the above method was subjected to a temperature of 360 ° C., a pressure of 200 kg / cm 2, and an hour using a compression molding machine (compression molding, WPHP10T, Ilshin Autoclave). The separator is manufactured under the retention time conditions.

 The following Table 2 measured the electrical conductivity and strength of the separator plate with a graphite and carbon nanotube 60wt% and 40wt% fluorine resin particles having a 500㎛ size. When graphite and carbon nanotubes are 60wt%, when carbon nanotubes are included, carbon nanotubes are 1wt% and graphite is 59wt%, and when carbon nanotubes are not added, graphite is added 60wt%. At this time, the electrical conductivity and strength were measured by varying the fluorine treatment conditions of graphite and carbon nanotubes. Each carbon material condition in Table 3 was changed as follows to measure the electrical conductivity and strength.

Example: Oxygen-oxyfluoride graphite + carbon nanotubes

Comparative Example 1: Graphite

Comparative Example 2: Oxygen-fluorinated Graphite + Oxygen-fluorinated Carbon Nanotube

Comparative Example 3: Graphite + Carbon Nanotubes

Electrical Conductivity (S / cm) Strength (MPa) Example 26.682 13.16 Comparative Example 1 6.131 9.68 Comparative Example 2 3.277 12.65 Comparative Example 3 40.502 10.80

Oxygen-fluorinated graphite + carbon nanotubes according to an embodiment of the present invention can be confirmed that the electrical conductivity is excellent, the strength is improved compared to the comparative example. In the case of Comparative Example 1 because only graphite is added, it is not possible to confirm the effect of increasing the electrical conductivity and strength that may be caused by the addition of carbon nanotubes. In Comparative Example 2, since the carbon nanotubes are oxyfluorinated, the electrical conductivity is lowered due to the defect of the carbon nanotubes, but the physical strength of the polymer fluorine resins is increased by the oxygen fluorinated graphite. Confirmed. Comparative Example 3 is a graphite and carbon nanotubes without fluorine treatment, the electrical conductivity is excellent compared to the example, but it can be seen that the strength is reduced compared to the example.

Conventionally, the weakness of the separator produced is weak due to weak interaction between the carbon material and the fluorine resin. However, when the graphite is fluorinated and mixed with the fluorine resin particles according to the present invention, a separator having a superior strength than that of the graphite is not obtained, and when carbon nanotubes are added and mixed together, two-dimensional graphite By connecting the conductive path of the particles, the conductivity is very good. In addition, when two-dimensional graphite and zero-dimensional fluororesin particles are mixed, they are evenly distributed by interfacial interaction.

Claims (9)

In the method for producing a polymer fluorocarbon-carbon powder using a carbon composite material having a multi-structure,
Fluorinating the two-dimensional graphite and pretreating the one-dimensional carbon nanotubes;
Forming a carbon composite material by mixing the two-dimensional graphite and one-dimensional carbon nanotubes;
Mixing the carbon composite material with 0-dimensional fluororesin particles to form a polymer fluorocarbon-carbon powder,
The two-dimensional graphite is hydrophilically coupled to the 0-dimensional fluororesin particles including a fluorine functional group on the surface, the two-dimensional graphite and the 0-dimensional fluororesin particles are subjected to high shear stress (inter shear) Method for producing a polymer fluorocarbon-carbon powder using a carbon composite material having a multi-structure, characterized in that the 0-dimensional fluorine resin particles are evenly distributed on the surface of the two-dimensional graphite. The method of claim 1,
Forming the polymer fluorocarbon-carbon powder,
The specific surface area of the 0-dimensional fluorocarbon resin particles is increased by milling the 0-dimensional fluorocarbon resin particles to form granules having a irregular surface in part due to high shear stress. The dimensional graphite is milled and peeled into a plate shape to increase the particle distribution, and thus the 0 dimensional fluororesin particles are evenly distributed on the 2D graphite surface by interfacial interaction with the 0D fluororesin particles. Method for producing a polymer fluorocarbon-carbon powder using a carbon composite material having a multi-structure characterized in. The method of claim 2,
The milling may be any one of a ball mill, a shaker mill, a vibratory mill, a planetary mill, or an attritor mill. Method for producing a polymer fluorocarbon-carbon powder using a carbon composite material having a multi-structure. The method of claim 1,
The pre-treatment of the one-dimensional carbon nanotubes,
Method for producing a polymer fluorocarbon-carbon powder using a carbon composite material having a multi-structure, characterized in that the one-dimensional carbon nanotubes are introduced into an organic solvent, dispersed using an ultrasonic irradiator, and powdered by lyophilization. The method of claim 1,
Fluorination of the two-dimensional graphite,
Polymeric fluorocarbon-carbon using a carbon composite material having a multi-structure characterized in that the two-dimensional graphite has a hydrophilic surface by combining a fluorine functional group and an oxygen functional group on the surface of the two-dimensional graphite by oxyfluorination treatment (oxyfluorination) Powder production method. The method of claim 5,
The oxygenated fluorine-containing fluorine-containing polymer fluorine using a carbon composite material having a multi-structure, characterized in that for 10 to 60 minutes in a reactor using a mixed gas consisting of fluorine gas and oxygen gas at a pressure of 0.01 to 1.0 bar Resin-Carbon Powder Preparation Method. In the method of manufacturing a polymer fluorocarbon-carbon composite using a carbon composite material having a multi-structure,
Fluorinating the two-dimensional graphite and pretreating the one-dimensional carbon nanotubes;
Forming a carbon composite material by mixing the two-dimensional graphite and one-dimensional carbon nanotubes;
Mixing the carbon composite material with 0-dimensional fluororesin particles to form a polymer fluorocarbon-carbon powder,
The two-dimensional graphite is hydrophilically bonded to the 0-dimensional fluorine resin particles, including a fluorine functional group on the surface, the two-dimensional graphite and the 0-dimensional fluorine resin particles are subjected to high shear stress (inter shear) Method for producing a polymer fluorocarbon-carbon composite using a carbon composite material having a multi-structure, characterized in that the 0-dimensional fluorine resin particles are evenly distributed on the surface of the two-dimensional graphite. In the polymer fluorocarbon-carbon powder using a carbon composite material having a multi-structure,
0-dimensional fluororesin particles;
One-dimensional carbon nanotubes in a debundling state;
The surface contains two-dimensional graphite modified with a fluorine functional group,
The two-dimensional graphite is hydrophilically coupled to the 0-dimensional fluororesin particles including a fluorine functional group on the surface, the two-dimensional graphite and the 0-dimensional fluororesin particles are subjected to high shear stress (inter shear) Polymeric fluorocarbon-carbon powder using a carbon composite material having a multi-structure, characterized in that the 0-dimensional fluorine resin particles are evenly distributed on the surface of the two-dimensional graphite. In the polymer fluorocarbon-carbon composite using a carbon composite material having a multi-structure,
0-dimensional fluororesin particles;
One-dimensional carbon nanotubes in a debundling state;
The surface contains two-dimensional graphite modified with a fluorine functional group,
The two-dimensional graphite is hydrophilically bonded to the 0-dimensional fluorine resin particles, including a fluorine functional group on the surface, the two-dimensional graphite and the 0-dimensional fluorine resin particles are subjected to high shear stress (inter shear) Polymeric fluorocarbon-carbon composite using a carbon composite material having a multi-structure, characterized in that the 0-dimensional fluorine resin particles are evenly distributed on the surface of the two-dimensional graphite.

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