A carbon / carbon composite material based on graphene and its precursor

Abstract

The present invention discloses a carbon / carbon composite material based on graphene and its precursor. The precursor includes a plurality of stacked carbon fiber fabric layers, the interior of the carbon fiber fabric layer is filled with resin and graphene, a graphene bonding layer is provided between adjacent carbon fiber fabric layers, and the oxygen content of the graphene is 0%-50%. The carbon fiber fabric layer of the precursor is filled with resin and graphene substrate, which not only realizes the internal reinforcement of the carbon fiber fabric layer, but also induces the glassy carbon formed by resin carbonization of the composite material precursor during carbonization and graphitization due to the presence of graphene. The degree of graphitization is increased, thereby obtaining a carbon / carbon composite material based on graphene with optimized performance.

Description

Technical Field

[0001] The present invention belongs to the technical field of carbon / carbon composite materials, and in particular relates to a graphene-based carbon / carbon composite material and a precursor thereof. Background Art

[0002] Carbon / carbon composite material is a composite material made of pyrolytic carbon as the matrix and carbon fiber as the reinforcing material. It has the advantages of low density, high thermal conductivity, ultra-high temperature mechanical properties, small thermal expansion coefficient, small friction coefficient, flexible structural designability, etc. These properties make it an important thermal structural material in the aerospace field, and gradually extend to fields such as mechanical braking and biomedicine, and have a very broad application space in industrial fields such as semiconductors, chemical industry, metallurgy, and atomic energy.

[0003] There are two main ways to form matrix carbon in carbon / carbon composites: (1) Carbonization at high temperature using asphalt or resin as a precursor. (2) Deposition of carbon source gas on the surface of the preform by controlling temperature and pressure. To prepare carbon / carbon composites using asphalt or resin as a precursor, it is necessary to first prepare a carbon fiber / asphalt-based or carbon fiber / resin-based reinforcement, and then carbonize it at high temperature to convert the asphalt phase or resin phase into a carbon matrix, thereby obtaining a carbon fiber reinforced carbon (carbon / carbon) composite. After that, the composite material is densified by repeated impregnation and carbonization treatments. Finally, a carbon / carbon composite material with a density that meets the standard is obtained through high-temperature graphitization treatment.

[0004] The basic structure of carbon / carbon composites is mostly a turbostratic graphite structure, or a transitional structure between a turbostratic graphite structure and a graphite crystal structure. Under the action of heat treatment, the interplanar spacing of carbon decreases, the size of graphite crystallites increases, and the process of transformation from a turbostratic graphite structure to a polycrystalline graphite structure is called graphitization. Graphitization can affect material properties. The deepening of graphitization can significantly enhance the fracture toughness and thermal conductivity of composite materials. However, the glassy carbon formed by the pyrolysis of resin is an amorphous carbon material (hard carbon) composed of disordered arrangement of carbon crystallites. The microcrystalline structure of glassy carbon is not oriented in a certain direction, and the long ribbon-like stacking of carbon layers constitutes a disordered network structure, which is difficult to graphitize, and thus directly affects the thermal physical properties, mechanical properties, friction and wear properties of carbon / carbon composites. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a graphene-based carbon / carbon composite material and its precursor, which improves the overall graphitization degree of the carbon / carbon composite material by constructing a specific material layer structure and utilizing the highly graphitized structure of graphene, and induces the increase in the graphitization degree of the matrix carbon itself, thereby solving the problem of low graphitization degree of carbon / carbon composite materials prepared by a resin precursor method and optimizing the performance of the composite material.

[0006] One of the technical solutions adopted by the present invention to solve its technical problem is: providing a graphene-based carbon / carbon composite material precursor, including a plurality of stacked carbon fiber fabric layers, the interior of the carbon fiber fabric layers is filled with resin and graphene, and a graphene bonding layer is provided between adjacent carbon fiber fabric layers, and the oxygen content of the graphene in the graphene bonding layer is 0%-50%.

[0007] In a preferred embodiment of the present invention, the carbon fiber fabric layer is immersed in a mixed solution of graphene and resin to achieve internal filling of resin and graphene.

[0008] In a preferred embodiment of the present invention, the mass ratio of graphene to resin in the mixed solution of graphene and resin is 5%.

[0009] In a preferred embodiment of the present invention, the resin content in the carbon fiber fabric layer is 40-50%.

[0010] In a preferred embodiment of the present invention, the resin includes but is not limited to phenolic resin and cyanate resin.

[0011] In a preferred embodiment of the present invention, the graphene in the graphene bonding layer and the graphene filled inside the carbon fiber fabric layer include graphene, graphene oxide or reduced graphene oxide.

[0012] In a preferred embodiment of the present invention, the number of layers of the graphene bonding layer is 1-20 layers.

[0013] In a preferred embodiment of the present invention, the carbon fiber fabric layer and the graphene adhesive layer are laminated and compounded by a molding process, and the molding process includes molding, vacuum bag pressing, lamination, autoclave or other molding processes.

[0014] The second technical solution adopted by the present invention to solve its technical problem is: providing a graphene-based carbon / carbon composite material, which is prepared by carbonizing and graphitizing a graphene-based carbon / carbon composite material precursor.

[0015] In a preferred embodiment of the present invention, a graphene-based carbon / carbon composite material precursor is carbonized, then repeatedly immersed in a mixed solution of graphene and resin, cured and carbonized, so that the glassy carbon formed by the resin fills the internal voids, and then graphitized to prepare the composite material.

[0016] Compared with the background technology, this technical solution has the following advantages:

[0017] 1. Graphene is a two-dimensional single-layer carbon material, only one atom thick, with a high degree of structural regularity, which is equivalent to a two-dimensional polymer material with a very high degree of graphitization. Graphene oxide is the oxide of graphene, and its surface contains abundant active groups such as hydroxyl, carboxyl, epoxy, carbonyl, etc., which can be well dispersed in solvents such as water, acetone and ethanol. After certain chemical or physical conditions, the oxygen-containing groups in graphene oxide can be partially reduced to reduced graphene oxide (schematic diagrams of the structures of several graphene-based materials are shown in the figure). Figure 1 The present invention improves the overall graphitization degree of the carbon / carbon composite material by constructing a specific material layer structure and utilizing the highly regular graphitized structure of graphene;

[0018] 2. Compared with graphene and reduced graphene oxide, graphene oxide has good compatibility with the resin matrix because it contains a large number of oxygen-containing groups in its structure, and can produce better chemical bonding and physical effects with the resin matrix. After a high-temperature thermal reduction process, graphene oxide can be converted into reduced graphene oxide, which has a regular structure and physical properties closer to graphene, so that the graphene oxide-resin system can be converted into a reduced graphene oxide-resin (graphene-resin) system by corresponding chemical or physical means. The present invention improves the degree of graphitization of the matrix carbon itself through graphene induction, thereby achieving performance optimization of carbon / carbon composite materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagrams of the structures of several graphene-based materials, (a) graphene, (b) graphene oxide, (c) reduced graphene oxide and (d) graphene oxide hydrogel film.

[0020] Figure 2 Schematic diagram of the composite material precursor structure (a) and molding diagram (b) in the embodiment, and schematic diagram of the structure of a common carbon / carbon composite material (c).

[0021] Figure 3 SEM photos of the internal microstructure of the composite materials, (a) carbon fiber / carbon composite material, (b) graphene / carbon fiber / carbon composite material.

[0022] Figure 4 The following are SEM photos of the internal microstructure of the composite material after multiple carbonizations: (a) carbonized once, (b) carbonized three times, (c) carbonized five times, and (d) carbonized seven times.

[0023] Figure 5 (a) XRD curve and (b) SEM micromorphology of the composite material of the embodiment.

[0024] Figure 6 Comparison of (a) electrical conductivity and (b) thermal conductivity of the embodiment and common carbon fiber / resin composite materials.

[0025] Figure 7 Schematic diagram of the preparation process of the embodiment. DETAILED DESCRIPTION

[0026] Example

[0027] The present embodiment provides a precursor of a graphene-based carbon / carbon composite material, comprising a plurality of stacked carbon fiber fabric layers, wherein the interior of the carbon fiber fabric layers is filled with resin and graphene oxide, and a graphene bonding layer is provided between adjacent carbon fiber fabric layers. The graphene bonding layer in the present embodiment is prepared using graphene oxide hydrogel, and the resin is phenolic resin.

[0028] The number of graphene bonding layers is 3, and the thickness of a single graphene bonding layer is 1 mm.

[0029] The method of preparing a carbon / carbon composite material by using the precursor of the graphene-based carbon / carbon composite material comprises the following steps:

[0030] (1) preparing a graphene oxide-acetone solution and a resin-acetone solution respectively, and mixing the graphene oxide-acetone solution and the resin-acetone solution uniformly to obtain a graphene oxide-resin-acetone solution; and controlling the ratio of graphene oxide to resin to be 5%.

[0031] (2) A single layer of carbon fiber fabric is immersed in a graphene oxide-resin-acetone solution, and then allowed to stand at room temperature to dry the solvent; a carbon fiber-graphene oxide-resin prepreg sheet is prepared according to a general fiber prepreg process; and the resin content in the prepreg sheet is controlled to be 45%.

[0032] (3) preparing a graphene oxide hydrogel with a mass concentration of 2%; brushing the graphene oxide hydrogel on the carbon fiber-graphene oxide-resin prepreg sheet prepared in step (2), bonding the carbon fiber-graphene oxide-resin prepreg sheets coated with the graphene oxide hydrogel in multiple layers, and drying.

[0033] (4) The carbon fiber-graphene oxide-resin prepreg sheet coated with the graphene oxide hydrogel in step (3) is molded using a corresponding molding process of a general fiber resin-based composite material, such as molding, vacuum bag pressing, lamination, autoclave, etc., to obtain a graphene oxide / carbon fiber / resin-based composite material.

[0034] (5) The graphene oxide / carbon fiber / resin-based composite material is carbonized by using a general resin precursor carbon / carbon composite material preparation process, and then impregnated and carbonized in the graphene oxide-resin-acetone solution of step (1). After repeated impregnation and carbonization, a graphene-based carbon / carbon composite material is obtained by graphitization.

[0035] This embodiment is based on the carbon / carbon composite material structure of graphene, and uses graphene substrate hydrogel as a bonding layer to bond carbon fiber fabric, so that the carbon fiber fabric interlayer in the composite material precursor is composed of graphene substrate layers, replacing the structure of the carbon fiber fabric interlayer composed of resin in the traditional carbon / carbon composite material precursor, so as to achieve the enhancement effect of the graphene structure between the composite material precursor layers. The structural comparison diagram is shown in FIG. Figure 2 The internal microstructure of the graphene / carbon fiber / carbon composite material formed through repeated impregnation and carbonization processes is as follows: Figure 3 and Figure 4 In the carbon / carbon composite precursor structure, the carbon fiber fabric layer is filled with resin and graphene, which not only realizes the reinforcement of the carbon fiber fabric layer, but also improves the graphitization degree of glassy carbon (hard carbon) formed by resin carbonization during the carbonization and graphitization process of the composite precursor due to the presence of graphene ( Figure 5 ), thereby optimizing the performance of carbon / carbon composites ( Figure 6 ).

[0036] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some or all of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A graphene-based carbon / carbon composite material precursor, characterized in that: The preparation method comprises the following steps: (1) preparing a graphene oxide-acetone solution and a resin-acetone solution respectively, and mixing the graphene oxide-acetone solution and the resin-acetone solution evenly to obtain a graphene oxide-resin-acetone solution; and controlling the ratio of graphene oxide to resin to be 5%; (2) impregnating a single layer of carbon fiber fabric in a graphene oxide-resin-acetone solution, leaving it to air at room temperature, and drying the solvent; preparing a carbon fiber-graphene oxide-resin prepreg sheet according to a general fiber prepreg process; and controlling the resin content in the prepreg sheet to be 40-50%; (3) preparing a graphene oxide hydrogel with a mass concentration of 2%; brushing the graphene oxide hydrogel on the carbon fiber-graphene oxide-resin prepreg sheet prepared in step (2), bonding the carbon fiber-graphene oxide-resin prepreg sheets coated with the graphene oxide hydrogel in multiple layers, and drying; (4) The carbon fiber-graphene oxide-resin prepreg sheet coated with the graphene oxide hydrogel in step (3) is molded using a corresponding molding process for a general fiber-resin-based composite material to obtain a graphene oxide / carbon fiber / resin-based composite material.

2. A graphene-based carbon / carbon composite material, characterized in that: The carbon / carbon composite material precursor based on graphene as claimed in claim 1 is prepared by carbonization and graphitization.

3. A graphene-based carbon / carbon composite material according to claim 2, characterized in that: The graphene oxide / carbon fiber / resin-based composite material is carbonized by adopting a preparation process of a general resin precursor, and then impregnated and carbonized in a graphene oxide-resin-acetone solution. After repeated impregnation and carbonization, a graphene-based carbon / carbon composite material is obtained by graphitization.

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