TW201410602A - Graphene reinforced composite - Google Patents

Abstract

The present invention relates to a graphene reinforced composite that includes: a graphene layer that dispersed from a graphene with a high degree of graphitization, and a matrix. The graphene layer is composed by a plurality of single or multilayer graphenes and is uniformly dispersed in the matrix.

Description

Graphene reinforced composite

The present invention relates to a graphene reinforced composite material, and more particularly to a graphene reinforced composite material which is blended with highly graphitized graphene.

Graphene is a flat structure with a single atomic thickness and sp ² bonded carbon atoms. Theoretically, graphene with a perfect hexagonal lattice structure can be closely packed and exhibits excellent electronic stability in the plane of the layered structure. Thermal conductivity. Although the excellent physical properties of graphene make it widely applicable to various devices to improve the electrical conductivity, thermal conductivity or strength of the device, however, since the physicists successfully separated graphene from graphite at the beginning of the millennium, there is still no An effective method for mass production of highly graphitized graphene. The conventional method of mass producing graphene is to process graphite at a high temperature and high pressure, forcing the carbon atoms in the graphite to rearrange into a planar hexagonal lattice structure. However, the hexagonal lattice structure of graphene produced in this way often cannot obtain a large extension distance in the plane direction (L _a ) of the graphene, and the hexagonal ring structure is often also broken, so that the produced graphene is obtained. The plane spacing (d ₍₀₀₀₂₎ ) is also much larger than the theoretical value, resulting in the physical properties of the produced graphene being less than expected.

The method of preparing a high crystallinity graphene sheet is provided by the inventors of the Republic of China Patent Publication No. 201022142 and No. 201131019, respectively. Wherein, the high-purity graphene is transmitted through the metal catalyst to rearrange the carbon atoms in the graphene into a perfect hexagonal lattice plane structure, as shown in FIG. 1 , which is a schematic diagram of the graphene crystal lattice of the present invention. Highly graphitized graphene sheets. Since the highly graphitized graphene has a perfect graphene plane, various physical properties are better than the conventionally prepared graphene, and the physicochemical properties of the composite material should be more improved in the composite material.

Accordingly, the use of the above highly graphitized graphene to prepare a graphene-reinforced composite material, which has better physical properties than the composite material produced by using conventional graphene, is necessary for its development.

The main object of the present invention is to provide a graphene reinforced composite material, which has a perfect graphene plane prepared by a carbon-dissolving method, and can be significantly improved by a small proportion of graphene. The physicochemical properties of the graphene reinforced composite.

To achieve the above object, an aspect of the present invention provides a graphene reinforced composite material comprising: a graphene layer formed by dispersing a highly graphitized graphene to form the graphene layer; and a matrix for the graphite The olefin layer is uniformly dispersed in the matrix, wherein the graphene layer may be composed of a plurality of single or multiple layers of graphene; in one aspect of the invention, preferably the graphene layer may be a plurality of layers of 1 to 10 More preferably, the graphene layer may be composed of a plurality of 1 to 3 layers of graphene. Preferably, the graphene layer may be composed of a plurality of single-layer graphene.

In order to achieve better mechanical strength of the prepared graphene reinforced composite material, the single-layer graphene selected for use in the present invention is a sheet-like structure composed of a perfect hexagonal crystal, so that the single-layer graphene has Above perfect a sheet-like structure of hexagonal crystals, which can be dispersed into a plurality of monolayers by a highly graphitized graphene prepared by a carbon deposition method as a dispersant, a supersonic wave or a combination thereof Graphene, wherein the highly graphitized graphene has a degree of graphitization of 0.8 to 1.0, preferably 0.9 to 1.0, more preferably 1.0, and the dispersant may be a surfactant to preferably disperse the sheets. Layer graphene.

In order to obtain the best mechanical strength by recombining a small amount of graphene in the graphene-reinforced composite material, the La-based plane of the dispersed single-layer graphene may be 1 nanometer. The meter is 1,000 nanometers, preferably 1 nanometer to 500 nanometers, more preferably 1 nanometer to 100 nanometers. In addition, it is known in the prior art that the preferred mechanical strength direction that graphene can provide is along the bottom dimension direction (L _a ), and vice versa, in the graphene plane pitch direction (d ₍₀₀₂₀₎ ), due to the graphene layer only With the weak bond force of van der Waals' forces, when the graphene layers composited in the graphene reinforced composite material are stacked in multiple layers, it is substantially easy to make the graphene reinforcement The graphene layer in the composite material becomes a defect. Accordingly, the thickness of the single-layer graphene used in the present invention may be 0.35 nm to 1 nm, that is, the single-layer graphene may be a stack of 1 to 3 layers to preferably reduce the above defects. . When the single-layer graphene prepared from the highly graphitized graphene is used, the content required for the composite of the graphene-reinforced composite material can be preferably reduced, as in one aspect of the present invention, The content of the graphene layer may be from 0.01 wt% to 20 wt%, preferably from 0.01 wt% to 10 wt%, based on the total weight of the graphene-reinforced composite.

In the present invention, the single-layer graphene may be compounded with a matrix of various materials as needed. In one aspect of the invention, the substrate may be at least one selected from the group consisting of plastic, rubber, rayon, natural fiber, and ceramic materials. A group of metal materials, or a combination thereof, but the invention is not limited thereto. Furthermore, in order to further improve the mechanical properties of the graphene reinforced composite material, the graphene reinforced composite material may further comprise an additive, the additive may be at least one selected from the group consisting of organic materials, metal materials, ceramic materials, or a combination thereof. In one aspect of the invention, an organic crosslinking agent may be used to enhance the bonding between the monolayer graphene and the matrix.

The graphene reinforced composite material prepared above can be applied to thermal grease, printed circuit board, conductive adhesive, light emitting diode, liquid crystal display, solar cell, pressure sensor, surface according to different substrates and additives selected. The acoustic wave filter, the resonator, the transistor, the capacitor, the transparent electrode, the UV laser, the DNA wafer, or a combination thereof, the present invention is not limited thereto.

Another object of the present invention is to provide a method for preparing a graphene reinforced composite material, which can significantly improve the physicochemical properties of the graphene reinforced composite material by compounding a single layer of graphene having a perfect graphene plane. .

In order to achieve the above object, an aspect of the present invention provides a method for preparing a graphene reinforced composite material, comprising: providing a highly graphitized graphene dispersed to a solvent to form a solution; and adding a dispersant to the solution And thoroughly mixing; dispersing the highly graphitized graphene into a graphene layer in the solution by using the dispersant; and mixing the solution with a matrix to form a graphene reinforced composite material, wherein the graphene layer Can be recovered Preferably, the graphene layer may be composed of a plurality of 1 to 10 layers of graphene, and more preferably the graphene layer may be composed of a plurality of 1s. It is composed of three layers of graphene, and it is preferable that the graphene layer be composed of a plurality of single-layer graphenes.

In one aspect of the invention, a surfactant can be used as the dispersant to preferably disperse the monolayers of graphene. In another aspect of the invention, the method further comprises simultaneously dispersing the highly graphitized graphene to form the graphene layer by an ultrasonic oscillating treatment.

In order to make the graphene reinforced composite material prepared by the method of the invention have better mechanical strength, the single-layer graphene selected for use in the present invention is a sheet-like structure composed of a perfect hexagonal crystal, and in order to make the sheets The layer graphene has a sheet-like structure of the above-mentioned perfect hexagonal crystals, which can be obtained by dispersing a highly graphitized graphene, wherein the highly graphitized graphene is obtained by a carbon dissolving method. The product has a degree of graphitization of from 0.8 to 1.0, preferably from 0.9 to 1.0, more preferably 1.0.

In order to obtain the best mechanical strength by recombining a small amount of graphene in the graphene-reinforced composite material, the La-based plane of the dispersed single-layer graphene may be 1 nanometer. The meter is 1,000 nanometers, preferably 1 nanometer to 500 nanometers, more preferably 1 nanometer to 100 nanometers. In addition, it is known in the prior art that the preferred mechanical strength direction that graphene can provide is along the direction of the bottom surface dimension, and vice versa, in the direction of the plane spacing of the graphene (d ₍₀₀₂₎ ), since there is only van der Waals between the graphene layers. The weak bond force of van der Waals' forces, so when the graphene layers composited in the graphene reinforced composite material are stacked in multiple layers, they are substantially easy to be located in the graphene reinforced composite material. The graphene layer becomes a defect. Accordingly, the thickness of the single-layer graphene used in the present invention may be 0.35 nm to 1 nm, that is, the single-layer graphene may be a single-layer to three-layer stack to preferably reduce the above. defect. When the single-layer graphene prepared from the highly graphitized graphene is used, the content required for the composite of the graphene-reinforced composite material can be preferably reduced, as in one aspect of the present invention, The content of the graphene layer may be from 0.01 wt% to 20 wt%, preferably from 0.01 wt% to 10 wt%, based on the total weight of the graphene-reinforced composite.

In the present invention, the single-layer graphene may be compounded with a matrix of various materials as needed. In one aspect of the invention, the substrate may be at least one selected from the group consisting of plastic, rubber, rayon, natural fiber, and ceramic materials. A group of metal materials, or a combination thereof, but the invention is not limited thereto. Furthermore, in order to further improve the mechanical properties of the graphene reinforced composite material, the graphene reinforced composite material may further comprise an additive, the additive may be at least one selected from the group consisting of organic materials, metal materials, ceramic materials, or a combination thereof. In one aspect of the invention, an organic crosslinking agent may be used to enhance the bonding between the monolayer graphene and the matrix. In the present invention, the type of plastic as the substrate is not limited, and may be a thermoplastic plastic such as polyethylene, polyvinyl alcohol, polypropylene, polyester, polyamide, polycarbonate, polytetrafluoroethylene, poly Acrylonitrile, polyvinyl vinyl alcohol copolymer and the like; the kind of rubber is not limited, and may be, for example, natural rubber, vulcanized rubber or synthetic rubber.

In addition to enhancing the bonding force between the two by means of additives, the affinity between the graphene layer and the substrate can be improved by a heat treatment or a chemical treatment. In one aspect of the invention, the graphene layer may be empty first After the sintering treatment, the surface roughness of the graphene layer may be increased to improve the affinity between the graphene layer; and in another aspect of the invention, the thermal oxidation method, the chemical oxidation method or the chemical doping method may be used. The graphene layer has a functional group on the surface of the graphene layer to increase its affinity with the matrix.

As used herein, "degree of graphitization" means the ratio of graphite, and the theoretical value of the distance between graphene planes is 3.354 angstroms, so when the degree of graphitization is 1, It refers to the most compact graphene stack with a graphite plane spacing (d ₍₀₀₀₂₎ ) of 3.354 angstroms. The degree of graphitization (G) can be calculated by the following formula 1: Formula 1 G=(3.440-d ₍₀₀₀₂₎ ) / (3.440-3.354)

Accordingly, the higher degree of graphitization corresponds to a larger crystal size, which is determined by the size of the bottom direction (La) of the planar structure of the hexagonal crystal of graphene and the size of the stacked layer (Lc). Thus, in general, high graphitization refers to a degree of graphitization greater than or equal to 0.8. However, the degree of graphitization of the highly graphitized graphene produced by the carbon-dissolving method selected in the present invention may be 0.8 or more. In some specific cases, the degree of graphitization is more than one.

Herein, "single-layer graphene" or "graphene layer" means a graphene comprising a single atomic layer and a plurality of layered stacks, and in the present invention, a single-layer to three-layer stacked graphene is preferred.

In this context, "La"based plane" refers to the size of a planar structure of graphene hexagonal crystals composed of a single atomic layer; "plane spacing direction (d ₍₀₀₀₂₎ )" refers to a single layer of graphene layer The direction of stacking, where pitch refers to the distance between the planes of graphene hexagonal crystals composed of a single atomic layer.

In this context, graphene treated by thermal oxidation or chemical oxidation can produce oxygen-containing functional groups of C=O, COOH, -OH or COC on a hexagonal crystal plane structure; wherein, by chemical doping Graphene, part of the carbon atoms in the hexagonal crystal plane structure is replaced by Group IIIA or VA elements; the above-mentioned graphene treated by thermal oxidation or chemical oxidation method can effectively improve the bonding strength between graphene and matrix And compatibility.

Herein, the kind of the surfactant is not particularly limited and may be an anionic, cationic, nonionic surfactant or a combination thereof.

Preparation example

Please refer to FIG. 2, which is a schematic diagram of the present invention for dispersing highly graphitized graphene to form a graphene layer by dispersing a highly graphitized graphene by a surfactant. Please refer to FIG. 3, which is a flow chart of preparing a graphene reinforced composite material of the present invention. In the preparation example of the present invention, the highly graphitized graphene 21 (S111) prepared by the carbon deposition method is dispersed in an ethyl acetate solution; then, a polystyrenesulfonic acid is used as the dispersing agent 22 And sufficiently mixing (S112) with the ethyl acetate solution containing the highly graphitized graphene 21 (S112), and ultrasonically oscillating (S113) the solution, so that the highly graphitized graphene in the solution can be dispersed into a plurality of single Layer graphene 211 (S114); accordingly, the preparation example of the present invention prepares an ethyl acetate solution containing a plurality of single-layer graphenes 211; further, in the present invention, highly graphitized graphene in a solution It can be highly graphitized as needed. The graphene is dispersed into a plurality of multilayer graphenes (for example, a 2-layer, 3-layer, or more layer stack structure), and the present invention is not limited thereto.

Example

In the first embodiment of the present invention, a natural rubber is selected as a substrate, and highly graphitized graphene is dissolved in ethyl acetate to prepare a solution. Referring to FIG. 3, the above solution containing a plurality of single-layer graphene and the natural rubber-containing solution are thoroughly mixed (S115), wherein the weight ratio of graphene to natural rubber is 1:99. After the above steps are completed, the natural rubber may be directly vulcanized and dried to form a graphene reinforced composite material containing a plurality of single-layer graphene. Please refer to FIG. 4 , which is a schematic diagram of the microstructure of a graphene reinforced composite material containing a plurality of single-layer graphenes according to a first embodiment of the present invention, wherein a plurality of single-layer graphene 411s prepared by the foregoing preparation examples are The single-layered sheet-like structure is uniformly dispersed in the vulcanized rubber as the matrix 43; accordingly, in this embodiment, the graphene-reinforced composite material 4 formed by vulcanizing rubber as the matrix 43 and strengthened by the single-layer graphene 411 is prepared, wherein These single-layer graphenes 411 are uniformly dispersed in the vulcanized rubber as the matrix 43.

In the second embodiment of the present invention, please refer to FIG. 5, which is a schematic diagram of a graphene reinforced composite material according to a second embodiment of the present invention. The preparation procedure of this embodiment is substantially the same as that of the first embodiment, except that since the matrix 53 is a polyethylene acrylic acid copolymer, the single-layer graphene 511 used in this embodiment undergoes a thermal oxidation. The treatment has an epoxy group (-COC-) on its surface to increase the affinity between the single-layer graphene 511 and the substrate 53. Next, when the epoxy group-containing single-layer graphene 511 is mixed with the matrix 53 composed of the polyethylene acrylic acid copolymer, the carboxyl group of the matrix 53 can be used. (-COOH) forms a covalent bond with the epoxy group (-COC-) of graphene 511 to increase the affinity between the two, thereby improving the mechanical strength of the graphene-reinforced composite material; accordingly, the preparation is completed in this embodiment. a graphene reinforced composite material, wherein the single layer graphene 511 and the matrix 53 composed of the polyethylene acrylic acid copolymer form a covalent bond with the carboxyl group via the epoxy group to further enhance the graphene reinforced composite material. Mechanical strength.

In the third embodiment of the present invention, please refer to FIG. 6 , which is a schematic diagram of another graphene reinforced composite material according to a third embodiment of the present invention. The preparation process of this embodiment is substantially the same as that of the first embodiment, and the difference lies in Since the matrix 63 is a polyvinyl alcohol, and the single-layer graphene 611 is subjected to a chemical oxidation treatment to produce a hydroxyl group (-OH) on the surface, this embodiment uses a di-epoxyoctane as a cross. a bonding agent 64, and combining the hydroxyl group-containing single-layer graphene 611 with the matrix 63 composed of the polyvinyl alcohol, thereby improving the mechanical strength of the graphene-reinforced composite material; accordingly, the embodiment is prepared. a graphene reinforced composite material, wherein the single-layer graphene 611 and the matrix 63 are cross-linked via a crosslinking agent 64 to crosslink the single-layer graphene 611 and a matrix 63 composed of polyvinyl alcohol, and further enhance The mechanical strength of the graphene reinforced composite.

Comparative example

Please refer to FIG. 7 , which is a schematic diagram of a graphene reinforced composite material according to a comparative example of the present invention, wherein the composition and preparation process of the comparative example are substantially the same as the first embodiment of the present invention, except that the graphene used in the comparative example is used. The dispersion step without the foregoing preparation example; that is, in the graphene-reinforced composite material 7 of the comparative example, the un-dispersed highly graphitized graphene 71 It is a stacked structure and dispersed in a matrix 73 composed of vulcanized rubber; accordingly, this comparative example prepares a graphene-reinforced composite material in which the undispersed highly graphitized graphene 71 is uniformly dispersed in The vulcanized rubber is composed of a matrix 73.

Test case

Please refer to FIG. 8 , which is a tensile strength diagram of the examples and comparative examples of the graphene reinforced composite material of the present invention, wherein the surfactant content and ultrasonic vibration are added by controlling the dispersion of highly graphitized graphene. The treatment time is adjusted to adjust the layering of the graphene and the dispersion in the matrix. As shown in FIG. 8, when the number of layers of graphene is smaller, that is, the larger the pitch of the single-layer graphene, the tensile strength of the prepared graphene-reinforced composite material is higher at the same content. Furthermore, even if the number of graphene stacking layers is the same, the more uniform the graphene is dispersed in the matrix, the higher the tensile strength of the prepared graphene-reinforced composite material. Therefore, the graphene-reinforced composite material prepared by the above method of the present invention can obtain a better mechanical strength by using a lower proportion of graphene.

The above-mentioned embodiments are merely examples for convenience of description, and the scope of the claims is intended to be limited to the above embodiments.

21,71‧‧‧ Graphene

211,411,511,611‧‧‧Single layer graphene

22‧‧‧Dispersant

4,7‧‧‧ Graphene reinforced composites

43,53,63,73‧‧‧Matrix

64‧‧‧Reagents

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic view of a graphene crystal lattice of the present invention.

2 is a schematic view of the present invention for dispersing highly graphitized graphene to form a graphene layer.

Figure 3 is a flow chart of the preparation of the graphene reinforced composite material of the present invention.

Fig. 4 is a schematic view showing the microstructure of the graphene reinforced composite material according to the first embodiment of the present invention.

Figure 5 is a schematic view of a graphene reinforced composite material according to a second embodiment of the present invention. Figure 6 is a schematic view of a graphene reinforced composite material according to a third embodiment of the present invention.

Fig. 7 is a schematic view showing a graphene-reinforced composite material of a comparative example of the present invention.

Figure 8 is a graph showing the tensile strength of the graphene reinforced composite material of the present invention.

4‧‧‧ Graphene reinforced composites

411‧‧‧Single layer graphene

43‧‧‧Material

Claims (28)

A graphene reinforced composite material comprising: a graphene layer formed by dispersing a highly graphitized graphene layer, wherein the graphene layer may be composed of a plurality of single or multiple layers of graphene; A matrix that uniformly disperses the graphene layer in the matrix. The graphene reinforced composite material according to claim 1, wherein the graphene layer is composed of a plurality of 1 to 10 layers of graphene, more preferably a plurality of 1 to 3 layers of graphene, and most It is composed of a plurality of single-layer graphenes. The graphene reinforced composite material according to claim 1, wherein the single-layer graphene is a sheet-like structure composed of a perfect hexagonal crystal. The graphene reinforced composite material according to claim 1, wherein the highly graphitized graphene is dispersed into the plurality of single-layer graphenes by a dispersing agent, a supersonic vibration or a combination thereof. The graphene reinforced composite material according to claim 4, wherein the dispersant is a surfactant. The graphene reinforced composite material according to claim 1, wherein the highly graphitized graphene is prepared by a carbon dissolving method. The graphene reinforced composite material according to claim 1, wherein the highly graphitized graphene has a degree of graphitization of 0.8 to 1.0. The graphene reinforced composite material according to claim 1, wherein the single-layer graphene has a La-based plane of from 1 nm to 1,000 nm. The graphene reinforced composite material according to claim 1, wherein the single-layer graphene has a thickness of 0.35 nm to 1 nm. The graphene reinforced composite material according to claim 1, wherein the graphene layer is contained in an amount of 0.01 wt% to 20 wt% based on the total weight of the graphene reinforced composite material. The graphene reinforced composite material according to claim 1, wherein the matrix is at least one selected from the group consisting of plastic, rubber, rayon, natural fiber, ceramic material, metal material, or a combination thereof. The graphene reinforced composite material according to claim 1, further comprising an additive selected from the group consisting of an organic material, a metal material, a ceramic material, or a combination thereof. The graphene reinforced composite material according to claim 1, wherein the graphene reinforced composite material is applied to a thermal grease, a printed circuit board, a conductive paste, a light emitting diode, a liquid crystal display, a solar cell, and a pressure sense. A detector, a surface acoustic wave filter, a resonator, a transistor, a capacitor, a transparent electrode, a UV laser, a DNA wafer, or a combination thereof. A method for preparing a graphene reinforced composite material, comprising: providing a highly graphitized graphene dispersed to a solvent to form a solution; adding a dispersant to the solution and thoroughly mixing; using the dispersant to make the highly graphitized Graphene in the solution Dispersing into a graphene layer, wherein the graphene layer may be composed of a plurality of single or multiple layers of graphene; and the solution is mixed with a matrix to form a graphene reinforced composite. The method of claim 14, further comprising dispersing the highly graphitized graphene to form the graphene layer by an ultrasonic vibration treatment. The method of claim 14, wherein the graphene layer is composed of a plurality of 1 to 10 layers of graphene, more preferably a plurality of 1 to 3 layers of graphene, preferably a plurality of graphenes. It consists of a single layer of graphene. The method of claim 14, wherein the single-layer graphene is a sheet-like structure composed of a perfect hexagonal crystal. The method of claim 14, wherein the dispersing agent is a surfactant. The method of claim 14, wherein the highly graphitized graphene is prepared by a carbon precipitation method. The method of claim 14, wherein the highly graphitized graphene has a degree of graphitization of from 0.8 to 1.0. The method of claim 14, wherein the single-layer graphene has a bottom direction dimension of from 1 nm to 1,000 nm. The method of claim 14, wherein the single-layer graphene has a thickness of 0.35 nm to 1 nm. The method of claim 14, wherein the graphene layer is present in an amount of from 0.01% by weight to 20% by weight based on the total weight of the graphene-reinforced composite material. The method of claim 14, wherein the substrate is at least one selected from the group consisting of plastic, rubber, rayon, natural fiber, ceramic material, metallic material, or a combination thereof. The method of claim 14, wherein the graphene reinforced composite further comprises an additive, the additive being at least one selected from the group consisting of organic materials, metallic materials, ceramic materials, or combinations thereof. The method of claim 14, wherein the method further comprises a heat treatment or a chemical treatment. The method of claim 26, wherein the heat treatment refers to an air burning method or a thermal oxidation method. The method of claim 26, wherein the chemical treatment refers to a chemical oxidation method or a chemical doping method.