Three-dimensional carbon fiber reinforced resin-based composite material and preparation method thereof

Abstract

The invention discloses a preparation method of a three-dimensional carbon fiber reinforced resin-based composite material, which comprises the following steps: preparing a three-dimensional carbon fiber fabric reinforcement by using mesophase pitch carbon fiber cloth as an XY-direction reinforcement and polyacrylonitrile-based carbon fiber as a Z-direction reinforcement; sequentially carrying out graphitization, electrochemistry and surface sizing treatment on the three-dimensional carbon fiber fabric reinforcement; the preparation method comprises the following steps: dispersing inorganic nano heat-conducting particles in organic resin to obtain a matrix resin system; and placing the three-dimensional carbon fiber fabric reinforcement in a mold, and injecting the matrix resin system by adopting an RTM (Resin Transfer Molding) process to obtain the composite material. The room-temperature XY-direction thermal conductivity of the composite material is 208-258 W / (m.K), the Z-direction thermal conductivity of the composite material is 5-54 W / (m.K), and the composite material has excellent mechanical properties, can be used for preparing aerospace aircraft structures / functional parts, and can also meet the requirements of other industrial equipment fields on light-weight, high-strength, high-modulus and high-thermal-conductivity composite materials.

Description

Technical Field

[0001] The invention belongs to the technical field of resin-based composite materials, and specifically relates to a method for preparing a three-dimensional high thermal conductivity carbon fiber reinforced resin-based composite material. Background Art

[0002] Carbon fiber reinforced resin-based composites have a series of excellent properties such as high specific modulus, high specific strength, and easy molding. They are widely used in aerospace structures and load-bearing components of high-end industrial equipment. As the scope of application continues to expand, fields such as satellite space thermal management systems and electronic industry heat sinks have urgent needs for lightweight, high-strength, and high-thermal conductivity resin-based composites. In carbon fiber reinforced resin-based composites, carbon fiber is both a reinforcement of the composite and an important carrier of heat transfer, which directly affects the final thermal conductivity of the composite. At present, the resin composites prepared with high-strength polyacrylonitrile-based carbon fibers have excellent mechanical properties, but average thermal conductivity. In order to improve the thermal conductivity of composite materials, high thermal conductivity mesophase asphalt carbon fibers can be used in the preparation of composite materials.

[0003] Mesophase pitch-based carbon fiber is a very important structural / functional fiber material made of mesophase pitch through melt spinning, oxidative carbonization and ultra-high temperature graphitization. Because the graphite crystal structure is highly oriented along the fiber axis, mesophase pitch carbon fiber has outstanding advantages such as high modulus, good stability, high thermal conductivity, small expansion coefficient, and zero expansion products. In the actual production of high thermal conductivity mesophase, it is divided into raw silk (300-600℃), high temperature carbonized silk (1000-1600℃) and graphitized silk (≥2800℃) according to the heating process flow. As the heating process temperature increases, the strength and modulus of the mesophase pitch fiber increase, resulting in the fiber being more easily lost and broken, and the subsequent processing performance deteriorates.

[0004] However, when directly using graphitized high thermal conductivity intermediate phase asphalt carbon fibers to prepare resin-based composites, the fiber modulus is very high (≥800GPa), and the fiber is easily damaged and broken during the preparation process, seriously affecting the mechanical and thermal conductivity of the high thermal conductivity carbon fibers. As a result, the prepared unidirectional or two-dimensional high thermal conductivity carbon fiber reinforced resin-based composites have high thermal conductivity in the unidirectional or XY plane, but low thermal conductivity and mechanical properties in the thickness direction, making it difficult to meet the comprehensive performance requirements of high-end products for lightweight and high thermal conductivity composite materials.

[0005] In summary, neither polyacrylonitrile-based carbon fibers nor mesophase asphalt-based carbon fibers can simultaneously meet the comprehensive requirements of carbon fiber reinforced resin-based composites for thermal conductivity, processing properties, and mechanical properties. Summary of the invention

[0006] The purpose of the present invention is to overcome the above defects and provide a three-dimensional carbon fiber reinforced resin-based composite material and a preparation method thereof, which solves the technical problem that the existing carbon fiber reinforced resin-based composite materials cannot simultaneously have high thermal conductivity, mechanical properties and processing properties. The composite material obtained by the present invention has a room temperature XY-direction thermal conductivity of 208 to 258 W / (m·K) and a Z-direction thermal conductivity of 5 to 54 W / (m·K). It also has excellent mechanical properties and can be used to prepare aerospace aircraft structural / functional components. It can also meet the needs of other industrial equipment fields for lightweight, high-strength, high-modulus, and high-thermal conductivity composite materials.

[0007] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0008] A method for preparing a three-dimensional carbon fiber reinforced resin-based composite material, comprising:

[0009] A three-dimensional carbon fiber fabric reinforcement is prepared by using a carbon cloth woven from mesophase pitch carbon fibers as an XY-direction reinforcement and using polyacrylonitrile-based carbon fibers as a Z-direction reinforcement. The mesophase pitch carbon fibers are mesophase pitch carbon fibers that have been subjected to a high-temperature carbonization treatment at 1000°C to 1600°C.

[0010] The three-dimensional carbon fiber fabric reinforcement is graphitized;

[0011] The three-dimensional carbon fiber fabric reinforcement after graphitization is placed in an alkaline electrolyte as a cathode for electrochemical treatment;

[0012] The electrochemically treated three-dimensional carbon fiber fabric reinforcement is impregnated with a sizing agent solution and then dried;

[0013] Dispersing inorganic nano thermally conductive particles in an organic resin to obtain a matrix resin system;

[0014] The dried three-dimensional carbon fiber fabric reinforcement is placed in a mold, and a matrix resin system is injected using the RTM process to obtain a three-dimensional carbon fiber reinforced resin-based composite material.

[0015] Furthermore, the carbon content of the mesophase pitch carbon fiber treated by high temperature carbonization at 1000°C to 1600°C is ≥98%, the tensile strength is ≥1200MPa, and the tensile modulus is ≥190GPa;

[0016] The polyacrylonitrile-based carbon fiber is one or more of T300-grade high-strength carbon fiber, T700-grade high-strength carbon fiber, T800-grade high-strength carbon fiber, M40J-grade high-strength and high-modulus carbon fiber, or M55J-grade high-strength and high-modulus carbon fiber.

[0017] Further, the carbon cloth weaving form includes one or more of plain cloth, satin cloth or twill cloth;

[0018] The three-dimensional carbon fiber fabric reinforcement was prepared by needle punching method;

[0019] The fiber volume content of the three-dimensional carbon fiber fabric reinforcement is 40% to 60%; the Z-direction needle punching spacing is 2mm to 6mm.

[0020] Furthermore, the temperature of the graphitization treatment is above 3000° C., the time is 1 to 2 hours, and the protective gas is nitrogen or argon.

[0021] Furthermore, the alkaline electrolyte is one or more of Ca(OH)2 or Ba(OH)2, and the concentration of the alkaline electrolyte is 0.1wt% to 2wt%; the anode is platinum, the DC voltage is 5V to 25V, and the current is 0.1A to 1A; the electrochemical treatment time is 5min to 10min.

[0022] Furthermore, the sizing agent includes one or more of an epoxy sizing agent or a phenolic sizing agent, the concentration of the sizing agent solution is 3wt% to 5wt%; and the infiltration time is 1min to 30min.

[0023] Furthermore, the inorganic nano thermally conductive particles are placed in a silane coupling agent solution for surface treatment and then dispersed in an organic resin;

[0024] The inorganic nano thermally conductive particles are carbon nanotubes or graphene;

[0025] The silane coupling agent is one or more of KH550 and KH560;

[0026] The organic resin is one or more of epoxy resin or phenolic resin; the epoxy resin includes one or more of 1,2-epoxycyclohexane 4,5-dicarboxylic acid diglycidyl ester or 3,4-epoxycyclohexylcarboxylic acid-3',4'-epoxycyclohexylmethyl ester; the phenolic resin includes one or more of high carbon phenolic resin or barium phenolic resin;

[0027] The concentration of the silane coupling agent solution is 1wt% to 3wt%.

[0028] Further, the matrix resin system comprises the following components in parts by mass:

[0029] Organic resin 100;

[0030] Inorganic nano thermal conductive particles 0.5~3;

[0031] Solvent 30~60.

[0032] Furthermore, the matrix resin system is injected by RTM process, and the three-dimensional carbon fiber reinforced resin matrix composite material is obtained after removing the solvent, heating and curing, cooling and demoulding;

[0033] When the organic resin is an epoxy resin, the solvent in the matrix resin system is one or more of acetone or tetrahydrofuran, the curing agent is one or more of hexahydrophthalic anhydride or methyl hexahydrophthalic anhydride, the mass fraction of the curing agent is 60 to 80 parts, the curing temperature is 100 to 200° C., and the curing time is 1 to 8 hours;

[0034] When the organic resin is a phenolic resin, the solvent in the matrix resin system is one or more of methanol or ethanol, the curing temperature is 120-200° C., and the curing time is 2-12 hours.

[0035] A three-dimensional carbon fiber reinforced resin-based composite material is obtained by adopting the preparation method of the three-dimensional carbon fiber reinforced resin-based composite material.

[0036] Compared with the prior art, the present invention has at least one of the following beneficial effects:

[0037] (1) The present invention uses two-dimensional carbon cloth woven from mesophase pitch carbon fibers and polyacrylonitrile-based carbon fibers for three-dimensional weaving, and graphitization treatment is used to ensure high mechanical properties and thermal conductivity of the reinforcement;

[0038] (2) The present invention electroplates the high thermal conductivity mesophase pitch carbon fiber with an alkaline electrolyte to generate a large amount of barbed inorganic salts on the surface of the carbon fiber, which significantly increases the surface area of ​​the carbon fiber and can be combined with the resin matrix to form a mechanical anchor, significantly improving the mechanical and thermal conductivity of the composite material;

[0039] (3) The present invention uses a silane coupling agent to treat inorganic nano-thermal conductive particles, so that the inorganic nano-thermal conductive particles are evenly dispersed in the organic resin matrix, which can effectively improve the thermal conductivity of the matrix resin. Combined with the three-dimensional carbon fiber fabric reinforcement, a multi-scale thermal conductive network is constructed, which is conducive to the full play of the thermal conductivity and mechanical properties of the composite material in the XY and Z directions;

[0040] (4) The present invention adopts the RTM process to prepare a three-dimensional carbon fiber reinforced resin-based composite material with high thermal conductivity. The process is mature and simple, the resin is evenly dispersed, and the thermal conductivity and mechanical properties are excellent. It is suitable for advanced equipment structure / functional components such as aerospace vehicles. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 This is a process flow chart of preparing a three-dimensional high thermal conductivity carbon fiber reinforced resin-based composite material according to the present invention;

[0042] Figure 2 This is an electron microscope photograph of the surface microstructure of the high thermal conductivity mesophase asphalt carbon fiber after electrochemical treatment of the present invention. DETAILED DESCRIPTION

[0043] The following detailed description of the present invention will make the features and advantages of the present invention more clear and explicit.

[0044] The word "exemplary" is used exclusively herein to mean "serving as an example, embodiment, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. Although various aspects of the embodiments are shown in the drawings, the drawings are not necessarily drawn to scale unless otherwise noted.

[0045] The present invention provides a method for preparing a three-dimensional carbon fiber reinforced resin-based composite material with high thermal conductivity. The carbon fiber composite material prepared by this method not only has high thermal conductivity in both the XY and Z directions, but also has excellent comprehensive mechanical properties. The present invention first uses high-temperature carbonized mesophase pitch carbon fibers to weave two-dimensional carbon cloth in the XY direction, and uses polyacrylonitrile-based carbon fibers as Z-direction reinforcing fibers to needle-weave into a three-dimensional carbon fiber fabric reinforcement, and then performs graphitization treatment to make the three-dimensional carbon fiber fabric have high thermal conductivity, thereby solving the problem that it is difficult to weave a three-dimensional fabric reinforcement by directly using high thermal conductivity carbon fibers with extremely high modulus and the fiber damage is relatively large; then the three-dimensional high thermal conductivity mesophase pitch carbon fiber fabric is used as a cathode for electroplating treatment in an alkaline electrolyte to generate a large number of barbed inorganic salts on the surface, such as Figure 2 As shown, the surface area of ​​the carbon fiber is significantly increased, which combines with the resin to form a mechanical anchor, thereby improving the mechanical and thermal conductivity of the composite material; the sizing treatment is used to further enhance the interfacial bonding force between the highly inert surface of the high thermal conductivity mesophase asphalt carbon fiber and the resin matrix; at the same time, the inorganic nano-thermal conductive particles are treated with a silane coupling agent and evenly dispersed in the organic resin matrix to improve the thermal conductivity of the matrix resin. Finally, the RTM process is used to prepare a three-dimensional high thermal conductivity carbon fiber reinforced resin-based composite material with good surface quality. The composite material with a multi-scale thermal conductive network has high thermal conductivity and mechanical properties in the XY and Z directions, which can be used to prepare aerospace vehicle structures / functional components, and can also meet the needs of other industrial equipment fields for lightweight, high-strength, high-modulus and high-thermal conductivity composite materials.

[0046] like Figure 1The present invention provides a method for preparing a three-dimensional carbon fiber reinforced resin-based composite material with high thermal conductivity. 1) First, the mesophase pitch carbon fiber that has been subjected to high-temperature carbonization treatment at 1000°C to 1600°C is woven into a carbon cloth as an XY-direction reinforcement, and polyacrylonitrile-based carbon fiber is used as a Z-direction reinforcement fiber (the XYZ directions in the present invention are three directions that are perpendicular to each other), and a three-dimensional carbon fiber fabric reinforcement is prepared by needle punching technology; 2) Then, the three-dimensional carbon fiber fabric reinforcement is placed in a graphitization furnace for ultra-high temperature graphitization treatment above 3000°C, and then placed in an alkaline The three-dimensional carbon fiber fabric reinforcement is electrochemically treated in an electrolyte, and finally immersed in a sizing agent solution of a certain concentration, taken out and dried to obtain a three-dimensional high thermal conductivity carbon fiber fabric reinforcement; 3) At the same time, the inorganic nano-thermal conductive particles are dispersed in a silane coupling agent solution for surface treatment, taken out and dried, and then dispersed in an organic resin solution to obtain a matrix resin system; 4) Finally, the three-dimensional high thermal conductivity carbon fiber fabric reinforcement is placed in a mold, and the matrix resin system is injected using the RTM process, the solvent is removed, heated for curing, and cooled for demolding to prepare a three-dimensional high thermal conductivity carbon fiber reinforced resin-based composite material.

[0047] In a specific embodiment, the carbon content of the mesophase pitch carbon fibers treated by high temperature carbonization at 1000-1600° C. is ≥98%, the tensile strength is ≥1200 MPa, and the tensile modulus is ≥190 GPa.

[0048] In a specific embodiment, the carbon cloth weaving form of step 1) includes at least one of plain cloth, satin cloth, and twill cloth; the polyacrylonitrile-based carbon fiber is at least one of T300, T700, T800 high-strength carbon fiber or M40J, M55J high-strength and high-modulus carbon fiber; the prepared three-dimensional carbon fiber fabric reinforced body fiber volume content is 40% to 60%; the Z-direction needle punching spacing is 2mm to 6mm.

[0049] In a specific embodiment, step 2) the graphitization heat treatment time is 1 to 4 hours, the protective gas is nitrogen or argon; the electrolyte is at least one of Ca(OH)2 or Ba(OH)2, and the solution concentration is 0.1% to 2%; the sizing agent type includes at least one of epoxy type or phenolic type, the sizing agent solution concentration is 3% to 5%, and the infiltration time is 1 min to 30 min.

[0050] In a specific embodiment, in step 3), the inorganic nano-thermal conductive particles are carbon nanotubes or graphene; the type of silane coupling agent is KH550 or KH560, the solution concentration is 1-3%, and the treatment time is 1-12 hours; the organic resin is epoxy resin or phenolic resin.

[0051] In a specific embodiment, the matrix resin system comprises the following components in parts by weight:

[0052] Organic resin matrix 100

[0053] Functionalized inorganic nano thermal conductive particles 0.5~3

[0054] Solvent 30~60.

[0055] In a specific embodiment, when the organic resin is an epoxy resin, the epoxy resin is 1,2-epoxycyclohexane 4,5-dicarboxylic acid diglycidyl ester or 3,4-epoxycyclohexyl 3',4'-epoxycyclohexyl methyl ester; the curing agent is at least one of hexahydrophthalic anhydride or methyl hexahydrophthalic anhydride, and the mass fraction of the curing agent is 60 to 80 parts; the curing temperature is 100 to 200° C., and the curing time is 1 to 8 hours.

[0056] In a specific embodiment, when the organic resin is a phenolic resin, the phenolic resin is a high carbon phenolic resin or a barium phenolic resin; no curing agent is required, the curing temperature is 120 to 200° C., and the curing time is 2 to 12 hours.

[0057] The present invention first uses high-temperature carbonized mesophase pitch carbon fiber to weave a two-dimensional carbon cloth as an XY-direction reinforcement, and then uses high-strength or high-modulus polyacrylonitrile-based carbon fiber as a Z-direction reinforcement fiber for needle-weaving into a three-dimensional carbon fiber fabric reinforcement, and then performs 3000°C graphitization to obtain a three-dimensional carbon fiber reinforcement with high thermal conductivity, which solves the problem that ultra-high modulus high thermal conductivity mesophase carbon fiber cannot be directly used to weave a three-dimensional carbon fiber reinforcement and the fiber loss is large, ensuring the utilization rate of thermal conductivity and mechanical properties of high thermal conductivity mesophase pitch carbon fiber. The present invention electroplates high thermal conductivity mesophase pitch carbon fiber with an alkaline electrolyte, generates a large number of barbed inorganic salts on the surface of the carbon fiber, significantly increases the surface area of ​​the carbon fiber, and can be combined with a resin matrix to form a mechanical anchor, significantly improving the mechanical and thermal conductivity of the composite material. The present invention uses a silane coupling agent to treat inorganic nano-thermal conductive particles and evenly disperses them in an organic resin matrix, improves the thermal conductivity of the matrix resin, and combines with a three-dimensional carbon fiber fabric reinforcement to construct a multi-scale thermal conductive network, which is conducive to the full utilization of thermal conductivity and mechanical properties of the composite material in the XY and Z directions. The present invention adopts RTM process to prepare three-dimensional carbon fiber reinforced resin-based composite materials with high thermal conductivity. The process is mature and simple, the resin is evenly dispersed, and the thermal conductivity and mechanical properties are excellent. It is suitable for advanced equipment structure / functional components such as aerospace vehicles.

[0058] Example:

[0059] In the following examples of the present invention, the density, tensile properties and compressive properties of the composite materials are tested according to the provisions of ASTM D-792, ASTM D-3039 and ASTM D-695, respectively, and the thermal conductivity is tested according to the provisions of ASTM E-1461.

[0060] Example 1

[0061] (1) The mesophase pitch carbon fibers treated with high temperature carbonization at 1000°C were woven into plain carbon cloth, which was cut into 200 mm × 200 mm as XY reinforcements, and T300-3K high-strength carbon fibers were used as Z reinforcement fibers. The Z-direction fiber bundle spacing was 2 mm. A three-dimensional carbon fiber fabric reinforcement with a fiber volume content of 60% was prepared by needle punching technology, and the size was 200 mm × 200 mm × 4 mm;

[0062] (2) placing the three-dimensional carbon fiber fabric reinforcement prepared in step (1) in a graphitization furnace for graphitization at 3000° C. for 4 hours under nitrogen protection; after cooling, placing it in a 2wt% Ba(OH)2 electrolyte for electrochemical treatment for 5 minutes, taking it out and soaking it in a 3wt% epoxy sizing agent solution for 5 minutes, taking it out and drying it in an oven to obtain a three-dimensional high thermal conductivity carbon fiber fabric reinforcement;

[0063] (3) Dispersing 1 part of carbon nanotubes in a 2 wt% KH-550 silane coupling agent solution for surface treatment for 12 h, taking out and drying, and then dispersing in epoxy resin (100 parts of 1,2-epoxycyclohexane 4,5-dicarboxylic acid diglycidyl ester + 60 parts of hexahydrophthalic anhydride + 50 parts of acetone) to obtain a matrix resin system;

[0064] (4) The three-dimensional high thermal conductivity carbon fiber fabric reinforcement described in step (2) is placed in a mold, and the epoxy matrix resin system prepared in step (3) is injected by RTM process, the solvent is removed, the product is heated for curing, and the product is cooled for demoulding. The curing process is (100°C / 2h)+(180°C / 4h), and the product is cooled and demoulded after oven curing to obtain a three-dimensional high thermal conductivity carbon fiber reinforced epoxy resin composite material. The properties of the composite material are shown in Table 1.

[0065] Example 2

[0066] (1) The mesophase pitch carbon fiber treated by high temperature carbonization at 1200°C was woven into a satin carbon cloth, which was cut into 200 mm × 200 mm as an XY reinforcement, and T800-6K high-strength medium modulus carbon fiber was used as a Z reinforcement fiber. The Z-direction fiber bundle spacing was 2 mm. A three-dimensional carbon fiber fabric reinforcement with a fiber volume content of 60% was prepared by needle punching technology, and the size was 200 mm × 200 mm × 4 mm;

[0067] (2) placing the three-dimensional carbon fiber fabric reinforcement prepared in step (1) in a graphitization furnace for graphitization at 3000° C. for 4 hours under nitrogen protection; after cooling, placing it in a 0.15wt% Ca(OH)2 electrolyte for electrochemical treatment for 10 minutes, then taking it out and soaking it in a 2wt% epoxy sizing agent solution for 10 minutes, taking it out and placing it in an oven for drying to obtain a three-dimensional high thermal conductivity carbon fiber fabric reinforcement;

[0068] (3) Dispersing 2 parts of carbon nanotubes in a 3 wt % KH-550 silane coupling agent solution for surface treatment for 10 h, taking out and drying, and then dispersing in epoxy resin (100 parts of 3,4-epoxycyclohexylcarboxylic acid-3',4'-epoxycyclohexyl methyl ester + 70 parts of methyl hexahydrophthalic anhydride + 40 parts of tetrahydrofuran) to obtain a matrix resin system;

[0069] (4) The three-dimensional high thermal conductivity carbon fiber fabric reinforcement described in step (2) is placed in a mold, and the epoxy matrix resin system prepared in step (3) is injected by RTM process, and placed in an oven for heating and curing. The curing process is (120°C / 2h)+(200°C / 4h). After oven curing, it is cooled and demolded to prepare a three-dimensional high thermal conductivity carbon fiber reinforced epoxy resin-based composite material. The properties of the composite material are shown in Table 1.

[0070] Example 3

[0071] (1) The mesophase pitch carbon fiber treated by high temperature carbonization at 1400°C was woven into a plain carbon cloth, which was cut into 200 mm × 200 mm as the XY reinforcement, and M40J-6K high strength and high modulus carbon fiber was used as the Z reinforcement fiber. The Z-direction fiber bundle spacing was 4 mm. A three-dimensional carbon fiber fabric reinforcement with a fiber volume content of 55% was prepared by needle punching technology, and the size was 200 mm × 200 mm × 3 mm;

[0072] (2) placing the three-dimensional carbon fiber fabric reinforcement prepared in step (1) in a graphitization furnace for graphitization at 3000° C. for 2 hours under nitrogen protection; after cooling, placing it in a 0.15wt% Ca(OH)2 electrolyte for electrochemical treatment for 10 minutes, taking it out and soaking it in a 3wt% phenolic sizing agent solution for 20 minutes, taking it out and placing it in an oven for drying to obtain a three-dimensional high thermal conductivity carbon fiber fabric reinforcement;

[0073] (3) Dispersing 1 part of graphene in a 2 wt% KH-560 silane coupling agent solution for surface treatment for 8 h, taking it out and drying it, and then dispersing it in a high carbon phenolic resin (100 parts of high carbon phenolic resin + 30 parts of methanol) to obtain a matrix resin system;

[0074] (4) The three-dimensional high thermal conductivity carbon fiber fabric reinforcement described in step (2) is placed in a mold, and the high carbon phenolic matrix resin system prepared in step (3) is injected by RTM process, and placed in an oven for heating and curing. The curing process is (120°C / 2h)+(180°C / 10h). After oven curing, it is cooled and demolded to prepare a three-dimensional high thermal conductivity carbon fiber reinforced epoxy resin composite material. The properties of the composite material are shown in Table 1.

[0075] Example 4

[0076] (1) The mesophase pitch carbon fiber treated by high temperature carbonization at 1400°C was woven into a satin carbon cloth, which was cut into 200 mm × 200 mm as an XY reinforcement, and M55J-6K high-strength and high-modulus carbon fiber was used as a Z-direction reinforcement fiber. The Z-direction fiber bundle spacing was 4 mm. A three-dimensional carbon fiber fabric reinforcement with a fiber volume content of 55% was prepared by needle punching technology, and the size was 200 mm × 200 mm × 3 mm;

[0077] (2) placing the three-dimensional carbon fiber fabric reinforcement prepared in step (1) in a graphitization furnace for graphitization at 3000° C. for 2 hours under nitrogen protection; after cooling, placing it in a 2wt% Ba(OH)2 electrolyte for electrochemical treatment for 10 minutes, then taking it out and soaking it in a 3wt% phenolic sizing agent solution for 10 minutes, taking it out and placing it in an oven for drying to obtain a three-dimensional high thermal conductivity carbon fiber fabric reinforcement;

[0078] (3) Dispersing 2 parts of graphene in a 2 wt% KH-560 silane coupling agent solution for surface treatment for 8 h, taking out and drying, and then dispersing in a barium phenolic resin (100 parts of barium phenolic resin + 40 parts of ethanol) to obtain a matrix resin system;

[0079] (4) The three-dimensional high thermal conductivity carbon fiber fabric reinforcement described in step (2) is placed in a mold, and the barium phenolic matrix resin system prepared in step (3) is injected by RTM process, and placed in an oven for heating and curing. The curing process is (120°C / 2h)+(180°C / 10h). After oven curing, it is cooled and demolded to prepare a three-dimensional high thermal conductivity carbon fiber reinforced epoxy resin composite material. The properties of the composite material are shown in Table 1.

[0080] Comparative Example 1:

[0081] The other steps are the same as those in Example 1, except that the electrochemical treatment step is omitted. The properties of the composite material are shown in Table 1.

[0082] Comparative Example 2:

[0083] The other steps were the same as those in Example 3, except that the silane coupling agent treatment step was omitted. The properties of the composite material are shown in Table 1.

[0084] Table 1 Properties of three-dimensional high conductivity carbon fiber reinforced resin composites

[0085]

[0086] It can be seen from Examples 1 to 4 that the three-dimensional high-conductivity carbon fiber reinforced resin composite material prepared by the present invention has a room temperature thermal conductivity of 208 to 248 W / (m·K) in the XY direction, a tensile strength of 208 to 248 MPa, a tensile modulus of 212 to 236 GPa, a room temperature thermal conductivity of 5 to 54 W / (m·K) in the Z direction, and a compressive strength of 222 to 252 MPa. It can be seen from Example 1 and Comparative Example 1 that the thermal conductivity and mechanical properties of the composite material obtained by electrochemical treatment are both high, especially the compressive strength is increased by 20%. It can be seen from Example 3 and Comparative Example 2 that the thermal conductivity and mechanical properties of the composite material obtained by treatment with a silane coupling agent containing inorganic thermal conductive particles are also high. It can be seen that the three-dimensional high-conductivity carbon fiber reinforced resin composite material prepared by the present invention has excellent thermal conductivity and mechanical properties in both the XY direction and the Z direction, and can be used in advanced equipment structures / functional components such as aerospace vehicles, which fully illustrates the effect of the present invention.

[0087] The present invention has been described in detail above in conjunction with specific implementations and exemplary examples, but these descriptions cannot be understood as limiting the present invention. Those skilled in the art understand that, without departing from the spirit and scope of the present invention, a variety of equivalent substitutions, modifications or improvements may be made to the technical solution of the present invention and its implementation methods, all of which fall within the scope of the present invention. The scope of protection of the present invention shall be subject to the attached claims.

[0088] The contents not described in detail in the specification of the present invention belong to the common knowledge of those skilled in the art.

Claims

1. A method for preparing a three-dimensional carbon fiber reinforced resin-based composite material, characterized in that: include: A three-dimensional carbon fiber fabric reinforcement is prepared by using a carbon cloth woven from mesophase pitch carbon fibers as an XY-direction reinforcement and using polyacrylonitrile-based carbon fibers as a Z-direction reinforcement. The mesophase pitch carbon fibers are mesophase pitch carbon fibers that have been subjected to a high-temperature carbonization treatment at 1000°C to 1600°C. The three-dimensional carbon fiber fabric reinforcement is graphitized; The three-dimensional carbon fiber fabric reinforcement after graphitization is placed in an alkaline electrolyte as a cathode for electrochemical treatment; The electrochemically treated three-dimensional carbon fiber fabric reinforcement is impregnated with a sizing agent solution and then dried; Dispersing inorganic nano thermally conductive particles in an organic resin to obtain a matrix resin system; The dried three-dimensional carbon fiber fabric reinforcement is placed in a mold, and a matrix resin system is injected using the RTM process to obtain a three-dimensional carbon fiber reinforced resin-based composite material.

2. The method for preparing a three-dimensional carbon fiber reinforced resin-based composite material according to claim 1, characterized in that: The carbon content of the mesophase pitch carbon fiber treated by high temperature carbonization at 1000℃~1600℃ is ≥98%, the tensile strength is ≥1200MPa, and the tensile modulus is ≥190GPa; The polyacrylonitrile-based carbon fiber is one or more of T300-grade high-strength carbon fiber, T700-grade high-strength carbon fiber, T800-grade high-strength carbon fiber, M40J-grade high-strength and high-modulus carbon fiber, or M55J-grade high-strength and high-modulus carbon fiber.

3. The method for preparing a three-dimensional carbon fiber reinforced resin-based composite material according to claim 1, characterized in that: The carbon cloth weaving form includes one or more of plain cloth, satin cloth or twill cloth; The three-dimensional carbon fiber fabric reinforcement was prepared by needle punching method; The fiber volume content of the three-dimensional carbon fiber fabric reinforcement is 40% to 60%; the Z-direction needle punching spacing is 2mm to 6mm.

4. The method for preparing a three-dimensional carbon fiber reinforced resin-based composite material according to claim 1, characterized in that: The temperature of graphitization treatment is above 3000°C, the time is 1 to 2 hours, and the protective gas is nitrogen or argon.

5. The method for preparing a three-dimensional carbon fiber reinforced resin-based composite material according to claim 1, characterized in that: The alkaline electrolyte is one or more of Ca(OH)2 or Ba(OH)2, and the concentration of the alkaline electrolyte is 0.1wt% to 2wt%; the anode is platinum, the DC voltage is 5V to 25V, and the current is 0.1A to 1A; the electrochemical treatment time is 5min to 10min.

6. The method for preparing a three-dimensional carbon fiber reinforced resin-based composite material according to claim 1, characterized in that: The sizing agent includes one or more of an epoxy sizing agent or a phenolic sizing agent, the concentration of the sizing agent solution is 3wt% to 5wt%; and the infiltration time is 1min to 30min.

7. The method for preparing a three-dimensional carbon fiber reinforced resin-based composite material according to claim 1, characterized in that: The inorganic nano thermally conductive particles are placed in a silane coupling agent solution for surface treatment and then dispersed in an organic resin; The inorganic nano thermally conductive particles are carbon nanotubes or graphene; The silane coupling agent is one or more of KH550 and KH560; The organic resin is one or more of epoxy resin or phenolic resin; the epoxy resin includes one or more of 1,2-epoxycyclohexane 4,5-dicarboxylic acid diglycidyl ester or 3,4-epoxycyclohexylcarboxylic acid-3',4'-epoxycyclohexylmethyl ester; the phenolic resin includes one or more of high carbon phenolic resin or barium phenolic resin; The concentration of the silane coupling agent solution is 1wt% to 3wt%.

8. The method for preparing a three-dimensional carbon fiber reinforced resin-based composite material according to claim 7, characterized in that: The matrix resin system comprises the following components in parts by weight: Organic resin 100; Inorganic nano thermal conductive particles 0.5~3; Solvent 30~60.

9. The method for preparing a three-dimensional carbon fiber reinforced resin-based composite material according to claim 7, characterized in that: The RTM process is used to inject the matrix resin system, remove the solvent, heat and cure, and cool and demould to obtain a three-dimensional carbon fiber reinforced resin matrix composite material; When the organic resin is an epoxy resin, the solvent in the matrix resin system is one or more of acetone or tetrahydrofuran, the curing agent is one or more of hexahydrophthalic anhydride or methyl hexahydrophthalic anhydride, the mass fraction of the curing agent is 60 to 80 parts, the curing temperature is 100 to 200° C., and the curing time is 1 to 8 hours; When the organic resin is a phenolic resin, the solvent in the matrix resin system is one or more of methanol or ethanol, the curing temperature is 120-200° C., and the curing time is 2-12 hours.

10. A three-dimensional carbon fiber reinforced resin-based composite material, characterized in that: The three-dimensional carbon fiber reinforced resin-based composite material is obtained by the preparation method of claims 1-10.

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