KR20130091820A - Fabrication methods of metal/polymer/ceramic matrix composites containing randomly distributed or directionally aligned graphenes by mechanical process - Google Patents

Abstract

PURPOSE: A mechanical dispersion method of graphene characterized in excellent graphene dispersion stability and excellent mechanical property including improved intensity and toughness compared with the conventional material, so that the process can be streamlined, is provided. CONSTITUTION: A mechanical dispersion method of graphene comprises the steps of: preparing graphene, mixing graphene with a matrix before being injected and dispersed on the matrix by adding mechanical energy to get the matrix deformed, and applying a mechanical mass transfer method to the above processed composite material for imposing directionality on the graphene. [Reference numerals] (AA) Foaming graphite, reduced graphene oxide; (BB) Metal, ceramic, polymer particles; (CC) Graphene (multi layers, multi layers); (DD) Inserting a mixture, ball mill or a dispersing stabilizer to a milling device in order; (EE) Mixing the mixture inserted in a milling device at low speed and in an inert atmosphere by using a cooling device and a gas control device; (FF) Evenly inserting and dispersing the graphene inside of metal, polymer, ceramic substrates by using mechanical shock energy from the ball to produce mixed powder; (GG) Imposing a directional nature on the graphene while molding the produced carbon nano composite powder into the graphene by using mechanical material moving method

Description

Fabrication methods of metal / polymer / ceramic matrix composites containing randomly distributed or directionally aligned graphenes by mechanical process

The present invention relates to a method for dispersing carbon nanomaterials, and more particularly, to mechanically disperse graphene, which is a planar carbon nanomaterial, into a metal, polymer, or ceramic matrix by mechanical processing. It is about.

Since the development of carbon nanomaterials, research on the method of mixing and dispersing various types of carbon nanomaterials with bases of metals, polymers, ceramics, etc. has been continuously conducted. Research has been limited to fibers, but the interest has recently shifted to graphene, which has been evaluated as having better physical properties than carbon nanotubes.

Regarding the dispersion method of carbon nanomaterials, Carbon (CL Xu et al., Vol. 37, 1999, p. 855-858) and Materials Science and Engineering (JW Ning et al., Vol. A313, 2001, p. 83-87) In the case of composite materials such as aluminum base reinforced with carbon nanotubes in a powder state, the molded article was manufactured by the sintering process and then evaluated. However, in the case of aluminum base, carbon nanotubes could not be uniformly dispersed in the material. Aggregate at the grain boundaries, such as a reduction in the sintering efficiency in the manufacture of the composite material, and also acted as a cause for reducing the mechanical and electrical properties of the material did not obtain a markedly improved properties.

See also Applied Physics Letters (Haihui Ye et al., Vol. 85, No. 10, 2004, p. 1775-1777) and Technical Digest of IVMC 2003 (Kunihiko et al., Vol. O 5-4, p. 49-50) shows a method of improving mechanical properties through complexing with carbon nanotubes or using FED (Field Emission Display) using electromagnetic properties of carbon nanotubes.

However, the conventional dispersing method described above employs a process of dispersing carbon nanomaterial in a solvent and then undergoing a complicated process such as drying, crushing, and sintering. Possible homogeneous dispersion methods are required. In addition, methods for securing the orientation of carbon nanomaterials including graphene have been studied through various methods to improve mechanical and electromagnetic properties. However, these studies are ongoing because demanding working conditions are required. to be.

On the other hand, as a method for uniformly dispersing graphene in a metal, a polymer, and a ceramic base, there is a result of uniformly dispersing graphene in a metal base by using a wet-metallurgy. The disadvantages of complex metal salt mixing, drying, calcination and reduction are complicated and time-consuming. Therefore, at present, due to the various process variables described above, it is difficult to implement reproducibility of quality, and the applicability to commercialization is low.

In addition, Patent Application No. 10-2009-0125703 (name of the invention: a method for producing graphene and graphene-nanometal composite powder using electric wire explosion, as the prior art related to the production of metal composite powder using graphene, hereinafter, “ Prior Art 1 ”), Patent Application No. 10-2011-7004820 (Invention: Graphene / SiC Composite Material Manufacturing Method and Graphene / SiC Composite Material Obtained thereby, hereinafter“ Prior Art 2 ”) And the like are known.

Prior art 1 is a method of dispersing graphene and metal powder by exploding the graphite rod and the metal wire in the fluid, because the graphene and the metal powder is simply dispersed in the liquid phase, segregation phenomenon occurs in the recovery process (drying and powdering) However, there is a disadvantage that cannot escape the limitation of the existing wet process. On the other hand, the prior art 2 is a method of combining the graphene on the surface of the SiC substrate by the composite of SiC and graphene has the disadvantages of the limitation of the size of the substrate growth and the dispersion and compounding of the graphene even inside the SiC material.

The present invention has been made to solve the above-described problems of the prior art, by inserting and dispersing the planar graphene uniformly in the base, and by providing the orientation to the dispersed graphene, mechanical, electrical, chemical properties, etc. An object of the present invention is to provide a mechanical dispersion method of graphene, which can easily implement various functions required according to the purpose.

As a means for solving the above technical problem,

The present invention, (a) preparing the graphene, and (b) mixing the graphene and the base and then applying mechanical energy to uniformly insert and disperse the graphene in the base through the deformation of the base And (c) by applying a mechanical mass transfer method to the composite material obtained through the step (b) provides a mechanical dispersion method of the graphene comprising the step of giving a direction to the graphene.

In this case, the step (a) may be made of a process of separating the graphene of a single layer or multiple layers through the liquid phase separation method or dry separation method from the expanded graphite or reduced graphene oxide.

In addition, the step (b) is the step of charging the graphene and the matrix in the container and mixing, adding a ball to the mixture of the graphene and the matrix and applying mechanical energy to the ball to move the ball Including the step of, the ball impacts the mixture so that the base is elastic or plastic deformation so that the graphene can be uniformly penetrated inside the base.

On the other hand, step (c) comprises the step of loading the composite material obtained in the step (b) in a container, maintaining the composite material at a constant temperature and pressing the composite material in one direction to deform As a result, the graphene may be provided with directionality.

In this case, the mechanical mass transfer method may be performed by any one or more selected from extrusion, rolling or injection.

In the present invention, the graphene may be added to 0.01 to 50wt% by weight ratio.

In the present invention, the base may be any one selected from metal, polymer or ceramic.

In this case, the metal is any one selected from aluminum (Al), copper (Cu), iron (Fe), zinc (Zn), magnesium (Mg), tungsten (W), silicon (Si) or titanium (Ti). It may be a pure metal or an alloy based on the pure metal.

In addition, the polymer may include any one selected from a thermoplastic resin, an elastomer, a thermosetting or a thermoplastic elastomer.

In addition, the ceramic may include any one or more selected from alumina, silica, zirconia or magnesia.

According to the present invention, it is possible to simplify the process by uniformly dispersing the graphene through known deformation by mechanical energy, and to obtain excellent graphene dispersion stability.

In addition, by providing the orientation to the graphene uniformly dispersed in the base using a mechanical material transfer method, not only can the mechanical properties such as strength, toughness, etc. be superior to existing materials, but also thermal and electrical properties are improved, thereby improving various industrial fields. Applicable to

1 is a process chart showing a mechanical dispersion method of graphene according to the present invention,
Figure 2 is a schematic diagram showing a comparison of the mechanical dispersion method of graphene according to the present invention and the graphene dispersion method according to the prior art,
3 is a photograph showing graphene separated into several layers or less from expanded graphite or reduced graphene oxide according to the present invention,
4 is a graph showing a tissue photograph and Raman spectrum analysis results of the composite prepared according to the present invention,
5 is a schematic view showing a process of arranging graphene in one direction within a substrate according to the present invention;
Figure 6 is a photograph showing the graphene dispersion of the composite prepared according to the present invention,
7 is a photograph analyzing the components of the composite prepared according to the present invention,
8 is a graph showing the tensile test results of the composite prepared according to the present invention.

Hereinafter, the present invention will be described in detail so that those skilled in the art can easily practice the present invention.

1 is a process chart showing a mechanical dispersion method of graphene according to the present invention, Figure 2 is a schematic diagram showing a comparison of the mechanical dispersion method of graphene according to the present invention and the graphene dispersion method according to the prior art.

As shown in Figure 1 and 2, the mechanical dispersion method of the graphene according to the present invention by using a mechanical method to uniformly disperse the graphene (graphene) in the matrix (matrix) after giving a direction to the graphene The technical features of the bar will be described in detail below.

First, a single layer or multilayer graphene having a crystal plane consisting of several layers or less is separated from expanded graphite or reduced graphene oxide spaced between layers. In this case, the graphene is a high energy such as liquid phase separation or attrition mill, ball mill, jet mill, etc. in which ultrasonic or vortex dispersion treatment is performed in organic and inorganic solvents. It can be separated by a dry separation method using mechanical energy of a high energy mill.

For reference, graphene generally has a strength of 30 GPa grade and an elastic modulus of 1TPa grade, but graphene usable in the present invention is carbon nano having a single layer or multilayer planar structure obtained from these in addition to expanded graphite and reduced graphene oxide. It includes all materials and does not require special limitation.

On the other hand, Figure 3 shows a single layer or multi-layer graphene dispersed by ultrasonic or vortex method from expanded graphite or reduced graphene oxide according to the present invention, from which the graphene obtained by the present invention shows a uniform size You can check it.

In addition, Figure 4 shows the SEM photograph of the composite powder prepared by inserting and dispersing the graphene in the aluminum base according to the present invention, and the results of Raman Spectrum (Raman Spectrum) analysis to confirm the presence of graphene, respectively, Raman From the results of the spectral analysis, the peaks inherent in the graphene indicate that graphene is stably dispersed in the spherical composite powder.

As described above, when the separation of graphene is completed, the separated graphene and matrix are mixed in the following process. Specifically, the graphene and the matrix are charged and mixed in a container, and a ball, which is a dispersion medium, is added to the mixture, and mechanical motion is applied to the ball. When the ball is moved as described above, the ball impacts the matrix and the graphene. Accordingly, the matrix causes elastic deformation or plastic deformation so that the graphene penetrates into the matrix and is uniformly dispersed.

That is, the present invention, as shown in Figure 2 by applying mechanical energy in order to prevent the phenomenon of interfering with the segregation and bonding of the metal particles between the graphene mutually generated by simply mixing and dispersing the conventional graphene and metal particles as shown in FIG. The pin is inserted and dispersed into the metal particles.

In the present invention, the known material may be a metal, a polymer, or a ceramic that is elastically or plastically deformable through a mechanical method, and is not particularly limited. For example, a series of metal materials including not only pure metals including aluminum (Al), copper (Cu), iron (Fe), zinc (Zn), silicon (Si) or titanium (Ti), but also alloys thereof, and thermosetting Synthetic polymers such as polypropylene (PP), polyethylene (PE), polyvinylchloride (PVC), polymethylmethacrylate (PMMA), rubber, etc., including resins, thermoplastics, elastomers Polymers of all kinds, including (synthetic polymers), and all single-components, including alumina (Al ₂ O ₃ ), silica (SiO ₂ ), magnesia (MgO), and zirconia (ZrO ₂ ) Any composite ceramic material containing at least one can be used.

On the other hand, when the graphene is dispersed in the matrix as described above, the dispersion time depends on the type of the matrix. For example, when manufacturing a nickel alloy composite, it is preferable to disperse the graphene by increasing the dispersion time than in the case of a pure aluminum composite. Also, when the metal grain composite of a specific grain size is to be prepared, the smaller the grain, It is desirable to increase the dispersion time.

Finally, as described above, when the graphene is uniformly inserted and dispersed in the matrix to obtain the carbon nanocomposite powder, the carbon nanocomposite powder is mechanically processed to impart orientation to the graphene.

Specifically, the carbon nano composite powder in which the graphene is uniformly dispersed is charged into a container, and maintained at a constant temperature (cold temperature to the melting temperature of the material), and then the carbon nano composite powder is deformed by pressing in one direction. It is arranged constantly along the pressed direction. That is, in the present invention to secure the orientation of the graphene is made through a mechanical mass flow method (mass flowing). In this case, the material movement method may be a mechanical processing method such as extrusion method, rolling, injection, etc. as shown in Figure 5, it is not particularly limited if the orientation of the graphene can be secured by causing the material movement. .

On the other hand, the mass transfer method is equally applicable to composites produced through the method according to the prior art as well as the method according to the present invention. That is, even in the case of a dispersion composite prepared by a chemical dispersion method using a dispersion solvent, which is one of the prior arts, the anisotropy of graphene may be secured by applying the mass transfer method of the present invention. It can be said that the applicability of the industrial field requiring mechanical and electromagnetic anisotropy can be greatly improved.

The mechanical dispersion method of graphene according to the present invention has been described in detail with reference to the accompanying drawings. As described above, the mechanical dispersion method of graphene according to the present invention can maximize production efficiency and reduce manufacturing cost by uniformly dispersing graphene in a substrate through a simple process without a complicated step as in the prior art. In addition, it is possible to greatly expand the industrial application range by improving the physical properties of the composite by securing the direction of graphene through mechanical processing method.

Hereinafter will be described a preferred embodiment of the present invention.

In this embodiment, the carbon nanocomposite was prepared by varying the fraction of matrix and graphene, and then the dispersion and anisotropy of graphene were measured. The results are shown in the following [Table 1].

Sample Number Composite
base Graphene
content
(Vol.%) Milling
Time
(Hrs) Milling speed
(RPM) Graphene dispersion Anisotropy
How to secure Graphene
Anisotropy Composite 1 Al One > 1 > 200 ○ Hot extrusion ○ 3 ○ Hot rolling ○ 5 ○ Hot extrusion ○ Composite 2 Cu One > 1 > 200 ○ Hot extrusion ○ 3 ○ Hot extrusion ○ 5 ○ Hot rolling ○ Composite 3 Ni One > 1 > 200 ○ Hot extrusion ○ 3 ○ Hot rolling ○ 5 ○ Hot extrusion ○ Composite 4 Fe One > 1 > 200 ○ Hot rolling ○ 3 ○ Hot extrusion ○ 5 ○ Hot extrusion ○ Composite 5 Zn One > 1 > 200 ○ Hot rolling ○ 3 ○ Hot extrusion ○ 5 ○ Hot extrusion ○ Composite 6 PMMA One > 1 > 200 ○ Hot rolling ○ 3 ○ Hot extrusion ○ 5 ○ Hot rolling ○ Composite 7 PVC One > 1 > 200 ○ Hot extrusion ○ 3 ○ Hot rolling ○ 5 ○ Hot extrusion ○ Composite 8 PE One > 1 > 200 ○ Hot rolling ○ 3 ○ Hot extrusion ○ 5 ○ Hot rolling ○ Composite 9 Al ₂ O ₃ One > 1 > 200 ○ Hot sintering ○ 3 ○ Hot sintering ○ 5 ○ Hot sintering ○ Composite 10 MgO One > 1 > 200 ○ Hot sintering ○ 3 ○ Hot sintering ○ 5 ○ Hot sintering ○ Composite 11 ZrO ₂ One > 1 > 200 ○ Hot sintering ○ 3 ○ Hot sintering ○ 5 ○ Hot sintering ○  * Mark O: shows uniform dispersion and orientation of graphene

As shown in Table 1, in the case of the metal, polymer and ceramic matrix composite uniformly dispersed in graphene, the uniform dispersion is obtained through mechanical processing regardless of the increase in the fraction of graphene under the milling time of 1 hour or more and the milling speed of 200 rpm or more. It can be confirmed. In addition, it can be seen from the results for graphene anisotropy of Table 1 that graphene can be arranged in one direction through the hot extrusion and hot rolling in the metal, polymer, and ceramic matrix composites.

On the other hand, Figure 6 shows the result of analysis by TEM after preparing the composite 1 of Table 1 using a high-temperature extrusion method of the present invention, from which it can be seen that the graphene is uniformly dispersed. In addition, FIG. 7 shows the results of component analysis for each of the internal parts of the composite 1 of Table 1, and the presence of graphene can be confirmed from the carbon concentration of the portion corresponding to the graphene.

In addition, Figure 8 shows the results of the tensile test at a strain of 10 ^-4 s ^-1 to confirm the mechanical properties of the graphene composite material prepared according to the present invention, tensile strength compared to pure aluminum due to the composite of graphene It can be seen that the increase of about 4 times, which is determined as a result that can confirm the dispersion strengthening effect of the graphene.

As mentioned above, the preferred embodiment of the present invention has been described in detail. It will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the appended claims.

Therefore, the scope of the present invention is defined by the appended claims rather than the foregoing detailed description, and all changes or modifications derived from the meaning, range, and equivalence of the claims are included in the scope of the present invention. .

Claims (10)

(a) preparing graphene;
(b) mixing the graphene with the matrix and applying mechanical energy to insert and disperse the graphene in the matrix through deformation of the matrix; And
(c) applying directivity to the graphene by applying a mechanical mass transfer method to the composite material obtained through the step (b);
Mechanical dispersion method of graphene comprising a. The method of claim 1,
The step (a) is a mechanical dispersion method of graphene, characterized in that to separate the graphene of a single layer or multiple layers through the liquid phase separation method or dry separation method from the expanded graphite or reduced graphene oxide. The method of claim 1,
The step (b)
Charging and mixing the graphene and the matrix in a container;
Adding a ball to the mixture of graphene and the matrix; And
Applying mechanical energy to the ball to move the ball;
Including, the ball impacts the mixture, the base is elastic or plastically deformed, so that the graphene penetrates the inside of the base by the mechanical dispersion method of the graphene. The method of claim 1,
The step (c)
Charging the composite material obtained through the step (b) into a container;
Maintaining the composite at a constant temperature; And
Deforming by pressing the composite material in one direction;
Including, the graphene mechanical dispersing method characterized in that the orientation is given to the graphene. The method of claim 1,
The mechanical mass transfer method is a mechanical dispersion method of graphene, characterized in that any one or more selected from extrusion, rolling or injection. The method of claim 1,
The graphene is mechanical dispersion method of graphene, characterized in that the addition of 0.01 to 50wt% by weight in the base. 7. The method according to any one of claims 1 to 6,
The matrix is a mechanical dispersion method of graphene, characterized in that any one selected from metal, polymer or ceramic. The method of claim 7, wherein
The metal is any one or more pure metals selected from aluminum (Al), copper (Cu), iron (Fe), zinc (Zn), magnesium (Mg), tungsten (W), silicon (Si) or titanium (Ti) or Mechanical dispersion method of graphene, characterized in that the alloy based on the pure metal. The method of claim 7, wherein
The polymer is a mechanical dispersion method of graphene, characterized in that it comprises any one selected from a thermoplastic resin, elastomer, thermosetting or thermoplastic elastomer. The method of claim 7, wherein
The ceramic is a mechanical dispersion method of graphene, characterized in that it comprises any one or more selected from alumina, silica, zirconia or magnesia.

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