Out-of-plane high-thermal-conductivity carbon fiber composite material and preparation method thereof

Abstract

The invention belongs to the technical field of carbon fiber composite materials, and discloses an out-of-plane high-thermal-conductivity carbon fiber composite material and a preparation method thereof. The preparation method of the out-of-plane high-thermal-conductivity carbon fiber composite material comprises the following steps that carbon fibers are placed in electro-deposition liquid to be subjected to electro-deposition treatment and then subjected to reduction treatment, composite carbon fibers are obtained, the composite carbon fibers are woven, and unidirectional cloth is obtained; activating the heat-conducting filler, and mixing the activated heat-conducting filler with a reactive diluent to obtain heat-conducting slurry; mixing the heat-conducting slurry, an epoxy resin curing agent and epoxy resin to obtain mixed slurry; and brushing the mixed slurry onto the surface of the unidirectional cloth, and then curing to obtain the composite material. According to the preparation method of the out-of-plane high-thermal-conductivity carbon fiber composite material provided by the invention, the mechanical property, the electric conductivity and the electromagnetic shielding property of the obtained composite material are improved on the basis of not changing the overall layer design of the original composite material.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon fiber composite materials, and in particular to an out-of-plane high thermal conductivity carbon fiber composite material and a preparation method thereof. Background Art

[0002] Carbon fiber reinforced resin (CFRP) has excellent in-plane thermal conductivity and is widely used in satellite main structures, functional structures, weaponry, and high-end consumer electronics. However, due to the thermal insulation effect of the resin, CFRP has a low out-of-plane thermal conductivity (0.5-2 W / m·K), which severely restricts its overall heat dissipation performance and limits the material's application range.

[0003] Patent CN 113105714A discloses a continuous high-thermal-conductivity asphalt-based carbon fiber-reinforced epoxy resin composite material and its preparation method. The method involves hydrolyzing thermally conductive inorganic particles with a silane coupling agent, washing and drying the particles, and then adding them to an epoxy resin matrix to prepare an epoxy resin adhesive. This method addresses the issues of fiber breakage and damage, as well as poor compatibility between the resin matrix and the fibers, while improving the in-plane thermal conductivity of unidirectional laminates. However, it does not address the impact on the thermal conductivity of the composite material through its thickness.

[0004] Patent CN 117103720A provides a high-modulus and high-thermal-conductivity carbon fiber-reinforced resin-based composite material and its preparation method. The method comprises: subjecting a mesophase pitch-based carbon fiber cloth and a mesophase pitch-based carbon fiber mat to high-temperature carbonization and graphitization; applying a layer of resin film to the upper and lower surfaces of the graphitized mesophase pitch-based carbon fiber mat, and hot-pressing the mat in a mold; stacking the hot-pressed mesophase pitch-based carbon fiber mat, resin film, mesophase pitch-based carbon fiber cloth and / or PAN-based carbon fiber cloth, and resin film in the mold in that order; performing the stacking cycle multiple times according to the above steps; placing the composite material in a hot press, gradually increasing the temperature and hot-pressing, cooling it, and removing it from the mold to obtain the composite material; and further heating the composite material and removing it after cooling. This method improves the in-plane thermal conductivity of the resin-based composite material but does not mention its impact on the out-of-plane thermal conductivity of the composite material.

[0005] Patent CN118372535A discloses a pitch-based carbon fiber composite material and its preparation method. This method utilizes highly thermally conductive mesophase pitch-based carbon fibers as reinforcing fibers and inserts a carbon nanofiber membrane doped with inorganic thermally conductive nanoparticles between layers of the reinforced resin-based composite material to produce a highly thermally conductive composite material. This method improves the in-plane thermal conductivity of the resin-based composite material but does not address the impact on the out-of-plane thermal conductivity of the composite material.

[0006] In the prior art, patent CN 119144030A provides an out-of-plane high thermal conductivity composite material and its preparation method. By mixing medium-cut fibers with short-cut fibers, the heat conduction path in the out-of-plane direction is increased, thereby improving the out-of-plane thermal conductivity coefficient and giving the composite material certain physical and mechanical properties, thereby improving its structural strength. However, the use of short-cut carbon fibers will affect the overall mechanical properties of the composite material.

[0007] Carbon fiber composites have anisotropic characteristics. The axial thermal conductivity of carbon fiber is high and the radial thermal conductivity is low. It is difficult to form a continuous thermal conductivity network in the direction perpendicular to the fiber. Constructing a heat transfer network between carbon fibers and between layers is the key to improving the out-of-plane thermal conductivity of composite materials and realizing the integration of material structure and function.

[0008] Therefore, it is of great significance to study and obtain a carbon fiber composite material with excellent mechanical properties and out-of-plane thermal conductivity and a preparation method thereof. Summary of the Invention

[0009] In view of this, the present invention provides an out-of-plane high thermal conductivity carbon fiber composite material and a preparation method thereof, the purpose of which is to solve the problems that the resin-based composite materials prepared by the prior art have excellent in-plane thermal conductivity but poor out-of-plane thermal conductivity and that the out-of-plane thermal conductivity and mechanical properties cannot be enhanced at the same time.

[0010] In order to achieve the above object, the present invention adopts the following technical solutions:

[0011] The present invention provides a method for preparing an out-of-plane high thermal conductivity carbon fiber composite material, comprising the following preparation steps:

[0012] 1) placing carbon fibers in an electrodeposition solution for electrodeposition treatment, and then performing a reduction treatment to obtain composite carbon fibers, and weaving the composite carbon fibers to obtain a unidirectional fabric;

[0013] 2) activating the thermally conductive filler and mixing it with a reactive diluent to obtain a thermally conductive slurry;

[0014] 3) mixing the thermal conductive slurry, the epoxy resin curing agent and the epoxy resin to obtain a mixed slurry;

[0015] 4) The mixed slurry is applied to the surface of the unidirectional fabric and then cured to obtain a composite material.

[0016] Preferably, in step 1), the electrodeposition solution is composed of the following components in parts by mass: 190-210 parts of nickel chloride, 35-45 parts of nickel sulfate, 25-35 parts of boric acid, 0.3-0.7 parts of sodium sulfamate, 15-20 parts of sodium lauryl sulfate, 5-15 parts of graphene oxide and 675-730 parts of water.

[0017] Preferably, in step 1), during the electrodeposition treatment, the cathode is connected to graphite, the anode is connected to a nickel block, the temperature of the electrodeposition solution is 50-60°C, and the current intensity is 0.1-0.2 A / cm 2 The electrodeposition treatment time is 45 to 60 seconds.

[0018] Preferably, in step 1), the reduction treatment is carried out under a nitrogen atmosphere, the temperature of the reduction treatment is 800-1200° C., and the time of the reduction treatment is 2-4 minutes;

[0019] The density of the unidirectional fabric is 180-220 g / m 2 .

[0020] Preferably, in step 2), the activation time is 10 to 15 minutes, and the activation pressure is 15 to 20 Pa;

[0021] The thermally conductive filler is dendritic graphene and / or amino-modified carbon nanotubes;

[0022] The active diluent is butyl glycidyl ether or phenyl glycidyl ether.

[0023] Preferably, in step 2), the mass ratio of the thermally conductive filler to the active diluent is 1:4.5-6.5;

[0024] The mixing time is 60 to 110 minutes, and the mixing temperature is 70 to 90°C.

[0025] Preferably, in step 3), the specific process of mixing the thermal conductive paste, epoxy resin curing agent and epoxy resin is: firstly mixing the thermal conductive paste and epoxy resin curing agent once to obtain a dispersion, and then mixing the dispersion with the epoxy resin for a second time to obtain a mixed paste;

[0026] The mass ratio of the thermal conductive paste to the epoxy resin curing agent is 1:2-4, and the mass ratio of the dispersion to the epoxy resin is 25-35:100;

[0027] The primary mixing is ultrasonic mixing, the ultrasonic mixing time is 25 to 35 minutes, and the ultrasonic mixing frequency is 40 to 80 kHz;

[0028] The secondary mixing is stirring mixing, the stirring mixing speed is 100-500 rpm, and the stirring mixing time is 3-10 minutes.

[0029] Preferably, in the step 4), curing is performed in a vacuum state with power on, the vacuum degree is ≥-0.095 MPa, and the power on voltage is 75-85V.

[0030] Preferably, in step 4), the curing includes a first curing and a second curing, wherein the temperature of the first curing is 80-95° C., the time of the first curing is 25-35 minutes, and the temperature of the second curing is 120-140° C., the time of the second curing is 100-130 minutes.

[0031] The present invention also provides an out-of-plane high thermal conductivity carbon fiber composite material prepared by the method for preparing the out-of-plane high thermal conductivity carbon fiber composite material.

[0032] It can be seen from the above technical solutions that compared with the prior art, the present invention has the following beneficial effects:

[0033] The present invention provides a method for preparing a carbon fiber composite material with high out-of-plane thermal conductivity, and while maintaining the overall layup design of the original composite material, the mechanical, electrical conductivity, and electromagnetic shielding properties of the resulting composite material are all improved. The preparation method significantly improves the out-of-plane thermal conductivity of the composite material at a low thermal conductive filler loading, reaching 2 to 6 W / m·K. The preparation method is feasible for engineering production. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0035] Figure 1 Schematic diagram of an apparatus for performing an electrodeposition treatment on carbon fibers in an electrodeposition solution according to the present invention;

[0036] Figure 2 Schematic diagram of the curing device in the present invention. DETAILED DESCRIPTION

[0037] The present invention provides a method for preparing an out-of-plane high thermal conductivity carbon fiber composite material, comprising the following preparation steps:

[0038] 1) placing carbon fibers in an electrodeposition solution for electrodeposition treatment, and then performing a reduction treatment to obtain composite carbon fibers, and weaving the composite carbon fibers to obtain a unidirectional fabric;

[0039] 2) activating the thermally conductive filler and mixing it with a reactive diluent to obtain a thermally conductive slurry;

[0040] 3) mixing the thermal conductive slurry, the epoxy resin curing agent and the epoxy resin to obtain a mixed slurry;

[0041] 4) The mixed slurry is applied to the surface of the unidirectional fabric and then cured to obtain a composite material.

[0042] In the present invention, in the step 1), the electrodeposition solution is preferably composed of the following components in parts by mass: 190-210 parts of nickel chloride, 35-45 parts of nickel sulfate, 25-35 parts of boric acid, 0.3-0.7 parts of sodium sulfamate, 15-20 parts of sodium lauryl sulfate, 5-15 parts of graphene oxide and 675-730 parts of water; the mass fraction of the nickel chloride is further preferably 195-205 parts, more preferably 200 parts, the mass fraction of the nickel sulfate is further preferably 38-44 parts, more preferably 40-4 2 parts by mass, the mass portion of the boric acid is further preferably 28 to 34 parts, more preferably 30 to 32 parts, the mass portion of the sodium sulfamate is further preferably 0.4 to 0.6 parts, more preferably 0.5 parts, the mass portion of the sodium lauryl sulfate is further preferably 16 to 19 parts, more preferably 17 to 18 parts, the mass portion of the graphene oxide is further preferably 7 to 12 parts, more preferably 8 to 10 parts, and the mass portion of the water is further preferably 680 to 720 parts, more preferably 690 to 700 parts.

[0043] In the present invention, the graphene oxide is preferably a porous dendritic graphene oxide obtained by chemical oxidation of natural cryptocrystalline graphite; the particle size of the natural cryptocrystalline graphite is preferably 0.3 to 0.5 μm, more preferably 0.35 to 0.45 μm, and more preferably 0.4 μm; the sheet size of the obtained porous dendritic graphene oxide is preferably 1.5 to 2.5 μm, more preferably 1.6 to 2.2 μm, and more preferably 1.8 to 2 μm.

[0044] In the present invention, the preparation method of the electrodeposition solution is preferably: nickel chloride, nickel sulfate, boric acid, sodium sulfamate, sodium lauryl sulfate and water are mixed, and then graphene oxide is added and ultrasonic dispersion is performed to obtain the electrodeposition solution; the frequency of the ultrasonic dispersion is preferably 18 to 22 kHz, more preferably 19 to 21 kHz, and more preferably 20 kHz, the power of the ultrasonic dispersion is preferably 750 to 850 W, more preferably 780 to 840 W, and more preferably 800 to 820 W, and the ultrasonic dispersion time is preferably 30 to 60 min, more preferably 40 to 55 min, and more preferably 45 to 50 min.

[0045] In the present invention, in the step 1), during the electrodeposition treatment, the cathode is connected to graphite, the anode is connected to the nickel block, the temperature of the electrodeposition solution is preferably 50-60°C, more preferably 52-58°C, more preferably 55-56°C, and the current intensity is preferably 0.1-0.2 A / cm 2 , more preferably 0.12 to 0.185 A / cm 2 , more preferably 0.15 to 0.16 A / cm 2The time of the electrodeposition treatment is preferably 45 to 60 s, more preferably 50 to 58 s, and even more preferably 52 to 55 s.

[0046] In the present invention, in step 1), the reduction treatment is preferably carried out under a nitrogen atmosphere, the reduction treatment temperature is preferably 800-1200° C., more preferably 900-1100° C., more preferably 950-1000° C., and the reduction treatment time is preferably 2-4 min, more preferably 2.5-3.5 min, more preferably 3 min;

[0047] The density of the unidirectional fabric is preferably 180 to 220 g / m 2 , more preferably 190 to 210 g / m 2 , more preferably 200 to 205 g / m 2 .

[0048] In the present invention, the electrodeposition treatment in step 1) is followed by washing and drying. The drying temperature is preferably 60-80°C, more preferably 65-75°C, and more preferably 70-72°C. The drying time is preferably 2-5 minutes, and more preferably 3-4 minutes.

[0049] In the present invention, in step 1), the carbon fiber is preferably unsized or desized continuous carbon fiber, and more preferably M55J carbon fiber, polyacrylonitrile-based carbon fiber or mesophase pitch carbon fiber.

[0050] In the present invention, in step 2), the activation is preferably carried out in a plasma cleaning machine, the activation time is preferably 10 to 15 minutes, more preferably 11 to 14 minutes, more preferably 12 to 13 minutes, and the activation pressure is preferably 15 to 20 Pa, more preferably 16 to 19 Pa, more preferably 17 to 18 Pa;

[0051] The thermally conductive filler is preferably dendritic graphene and / or amino-modified carbon nanotubes;

[0052] The reactive diluent is preferably butyl glycidyl ether or phenyl glycidyl ether.

[0053] In the present invention, the thermally conductive filler is preferably dendritic graphene or a mixture of dendritic graphene and amino-modified carbon nanotubes. In the mixture, the mass ratio of dendritic graphene to amino-modified carbon nanotubes is preferably 10:0-2.5, more preferably 10:0.5-2, and even more preferably 10:1-1.5.

[0054] In the present invention, the dendritic graphene is prepared by a liquid phase exfoliation method, and the sheet size of the dendritic graphene is preferably 5 to 10 μm, more preferably 6 to 9 μm, and more preferably 7 to 8 μm;

[0055] The amino-modified carbon nanotubes are preferably multi-walled carbon nanotubes, the diameter of the multi-walled carbon nanotubes is preferably 25-50 nm, more preferably 30-45 nm, more preferably 35-40 nm, and the length of the multi-walled carbon nanotubes is preferably 3-12 μm, more preferably 5-10 μm, more preferably 6-8 μm.

[0056] In the present invention, in step 2), the mass ratio of the thermally conductive filler to the reactive diluent is preferably 1:4.5-6.5, more preferably 1:4.8-6.2, and more preferably 1:5-5.5;

[0057] The mixing time is preferably 60 to 110 min, more preferably 70 to 100 min, and more preferably 80 to 90 min. The mixing temperature is preferably 70 to 90°C, more preferably 75 to 85°C, and more preferably 80 to 82°C.

[0058] In the present invention, in the step 2), the mixing is preferably performed by ultrasonic mixing first and then stirring mixing; the power of the ultrasonic mixing is preferably 40-80 kHz, more preferably 45-70 kHz, more preferably 50-60 kHz, the ultrasonic mixing time is preferably 20-40 min, more preferably 25-35 min, more preferably 30 min, the stirring mixing speed is preferably 100-500 rpm, more preferably 200-400 rpm, more preferably 300-350 rpm, the stirring mixing temperature is preferably 70-90°C, more preferably 75-85°C, more preferably 80-82°C, and the stirring mixing time is preferably 50-70 min, more preferably 55-65 min, more preferably 60 min.

[0059] In the present invention, in step 3), the specific process of mixing the thermal conductive paste, epoxy resin curing agent and epoxy resin is as follows: firstly, the thermal conductive paste and epoxy resin curing agent are mixed once to obtain a dispersion, and then the dispersion is mixed twice with the epoxy resin to obtain a mixed paste;

[0060] The mass ratio of the thermal conductive paste to the epoxy resin curing agent is preferably 1:2-4, more preferably 1:2.5-3.5, more preferably 1:3, and the mass ratio of the dispersion to the epoxy resin is preferably 25-35:100, more preferably 28-34:100, more preferably 30-32:100;

[0061] The primary mixing is preferably ultrasonic mixing, the ultrasonic mixing time is preferably 25 to 35 minutes, more preferably 26 to 32 minutes, more preferably 28 to 30 minutes, and the ultrasonic mixing frequency is preferably 40 to 80 kHz, more preferably 45 to 70 kHz, more preferably 50 to 60 kHz;

[0062] The secondary mixing is preferably stirring mixing, the stirring mixing speed is preferably 100-500 rpm, more preferably 200-400 rpm, more preferably 300-350 rpm, and the stirring mixing time is preferably 3-10 min, more preferably 5-8 min, more preferably 6-7 min.

[0063] In the present invention, in the step 4), curing is preferably carried out in a vacuum and energized state, the vacuum degree is preferably ≥-0.095MPa, more preferably ≥-0.09MPa, more preferably ≥-0.085MPa, and the energized voltage is preferably 75-85V, more preferably 78-84V, more preferably 80-82V.

[0064] In the present invention, in the step 4), the curing includes a first curing and a second curing. The temperature of the first curing is preferably 80-95°C, more preferably 85-92°C, and more preferably 88-90°C. The time of the first curing is preferably 25-35 min, more preferably 28-34 min, and more preferably 30-32 min. The temperature of the second curing is preferably 120-140°C, more preferably 125-135°C, and more preferably 130-132°C. The time of the second curing is preferably 100-130 min, more preferably 105-125 min, and more preferably 110-120 min.

[0065] In the present invention, in the step 4), cooling is performed after solidification, and the cooling is preferably natural cooling. The cooling temperature is preferably 50-70°C, more preferably 55-65°C, and more preferably 60°C.

[0066] In the present invention, in the step 4), during the coating process, the mass ratio of the unidirectional cloth to the mixed slurry is preferably 5-7:3-5, more preferably 5-7:4, and even more preferably 6:4.

[0067] In the present invention, in step 4), curing is preferably performed by a vacuum bag pressing process. In the vacuum bag pressing process, the flat mold and the equalizing plate are preferably metal; in the vacuum bag pressing process, the order from bottom to top is flat mold, insulating release film, mixed slurry, unidirectional cloth, mixed slurry, unidirectional cloth... mixed slurry, insulating release film, equalizing plate, isolation film, breathable felt and vacuum bag;

[0068] In the vacuum bag pressing process, the flat mold and the equalizing plate in the vacuum bag are connected to electrodes, and the applied electric field strength is preferably 20 to 50 V / mm, more preferably 25 to 45 V / mm, and even more preferably 30 to 40 V / mm.

[0069] The present invention also provides an out-of-plane high thermal conductivity carbon fiber composite material prepared by the method for preparing the out-of-plane high thermal conductivity carbon fiber composite material.

[0070] The technical solutions provided by the present invention are described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0071] In the embodiment of the present invention, the model of the plasma cleaning machine is PDC-36G / 220V; the epoxy resin curing agent is purchased from Shenzhen Langbowan Advanced Materials Co., Ltd., the epoxy resin is purchased from Shenzhen Langbowan Advanced Materials Co., Ltd., and the insulating release film is purchased from Higashiyama Film Co., Ltd. of Japan;

[0072] Example 1

[0073] 200 g of nickel chloride, 40 g of nickel sulfate, 30 g of boric acid, 0.5 g of sodium sulfamate, and 15 g of sodium lauryl sulfate were weighed, and deionized water was added to a total volume of 1 L. After mixing, 10 g of graphene oxide (porous dendritic graphene oxide with a sheet size of 2 μm prepared by chemical oxidation-reduction method of natural cryptocrystalline graphite with a particle size of 0.4 μm) was added, and the solution was ultrasonically dispersed at a frequency of 20 kHz and a power of 800 W for 30 min to obtain an electrodeposition solution;

[0074] The M55J carbon fiber was immersed in an electroplating solution at 55°C for electroplating treatment, wherein the cathode was connected to the graphite and the anode was connected to the nickel block. The current intensity was adjusted to 0.15 A / cm 2 By controlling the wire speed of M55J carbon fiber, the deposition time of M55J carbon fiber in the electrodeposition solution is 60s. After the electrodeposition is completed, it is washed and dried in sequence (temperature is 70℃, time is 5min). The dried carbon fiber is placed in a graphite furnace and reduced at 1000℃ for 3min under nitrogen atmosphere to obtain composite carbon fiber. The composite carbon fiber is woven into a fiber with a density of 200g / m 2 One-way fabric;

[0075] Dendritic graphene (average sheet size of 10 μm) and amino-modified carbon nanotubes (average diameter of 50 nm, length of 12 μm) were mixed uniformly in a weight ratio of 10:1, and then placed in a plasma cleaner for activation treatment at an air pressure of 15 Pa for 15 minutes to obtain an activated thermally conductive filler. The activated thermally conductive filler was added to butyl glycidyl ether in a mass ratio of 1:5, and ultrasonically dispersed at a power of 80 kHz for 30 minutes, and then stirred at a speed of 300 rpm at 80°C for 1 hour to obtain a thermally conductive slurry;

[0076] The thermal conductive slurry was added to the epoxy resin curing agent at a mass ratio of 1:3, and ultrasonically dispersed at a power of 50 kHz for 30 minutes to obtain a dispersion liquid. The dispersion liquid and the epoxy resin were then stirred at a speed of 400 rpm for 5 minutes at a mass ratio of 30:100 to obtain a mixed slurry;

[0077] Weigh equal masses of mixed slurry and unidirectional cloth, lay a layer of insulating release film on a stainless steel flat mold, then apply the mixed slurry and lay the carbon fiber unidirectional cloth in sequence, repeat 10 times, apply the mixed slurry on the last layer of carbon fiber unidirectional cloth, and then lay the insulating release film, stainless steel equalizing plate, isolation film, breathable felt and vacuum bag in sequence, and connect the positive and negative electrodes to the flat mold and equalizing plate respectively;

[0078] The vacuum degree in the vacuum bag was set to -0.095 MPa, the positive and negative electrodes were energized with a voltage of 80 V and an electric field strength of 36 V / mm; the composite material was first cured at 90°C for 30 minutes and then at 130°C for 120 minutes. The composite material was naturally cooled to 60°C and then demolded to obtain the composite material.

[0079] According to tests, the composite material obtained in this embodiment has an interlaminar shear strength of 64 MPa and an out-of-plane thermal conductivity of 3.47 W / m·K.

[0080] Example 2

[0081] 200 g of nickel chloride, 40 g of nickel sulfate, 30 g of boric acid, 0.5 g of sodium sulfamate, and 15 g of sodium lauryl sulfate were weighed, and deionized water was added to a total volume of 1 L. After mixing, 15 g of graphene oxide (porous dendritic graphene oxide with a sheet size of 2 μm prepared by chemical oxidation-reduction method of natural cryptocrystalline graphite with a particle size of 0.4 μm) was added, and the solution was ultrasonicated at a frequency of 20 kHz and a power of 800 W for 60 min to obtain an electrodeposition solution;

[0082] The TYG-1 mesophase pitch-based carbon fiber was immersed in an electrodeposition solution at 55°C for electrodeposition treatment, wherein the cathode was connected to the graphite and the anode was connected to the nickel block. The current intensity was adjusted to 0.15 A / cm 2By controlling the wire feeding speed of TYG-1 mesophase pitch-based carbon fiber, the deposition time of TYG-1 mesophase pitch-based carbon fiber in the electrodeposition solution is 60s. After the electrodeposition is completed, the carbon fiber is washed and dried in sequence (temperature is 70℃, time is 5min). The dried carbon fiber is then placed in a graphite furnace and reduced at 1200℃ for 2min under a nitrogen atmosphere to obtain a composite carbon fiber. The composite carbon fiber is woven into a fiber with a density of 200g / m 2 One-way fabric;

[0083] Dendritic graphene (average sheet size of 10 μm) and amino-modified carbon nanotubes (average diameter of 50 nm, length of 12 μm) were mixed in a weight ratio of 10:1, and then placed in a plasma cleaner for activation treatment at an air pressure of 15 Pa for 15 minutes to obtain an activated thermally conductive filler. The activated thermally conductive filler was added to butyl glycidyl ether in a mass ratio of 1:5, and ultrasonically dispersed at a power of 80 kHz for 30 minutes, and then stirred at a speed of 300 rpm at 80°C for 1 hour to obtain a thermally conductive slurry;

[0084] The thermal conductive slurry was added to the epoxy resin curing agent at a mass ratio of 1:3, and ultrasonically dispersed at a power of 50 kHz for 30 minutes to obtain a dispersion liquid. The dispersion liquid and the epoxy resin were then stirred at a speed of 400 rpm for 5 minutes at a mass ratio of 30:100 to obtain a mixed slurry;

[0085] Weigh equal masses of mixed slurry and unidirectional cloth, lay a layer of insulating release film on a stainless steel flat mold, then apply the mixed slurry and lay the carbon fiber unidirectional cloth in sequence, repeat 10 times, apply the mixed slurry on the last layer of carbon fiber unidirectional cloth, and then lay the insulating release film, stainless steel equalizing plate, isolation film, breathable felt and vacuum bag in sequence, and connect the positive and negative electrodes to the flat mold and equalizing plate respectively;

[0086] The vacuum degree between the flat mold and the equalizing plate was set to -0.095 MPa, the positive and negative electrodes were energized with a voltage of 100 V and an electric field strength of 45 V / mm; the composite material was first cured at 90°C for 30 minutes and then at 130°C for 120 minutes. The composite material was demoulded after cooling to 60°C to obtain the composite material.

[0087] According to tests, the composite material obtained in this embodiment has an interlaminar shear strength of 52 MPa and an out-of-plane thermal conductivity of 5.58 W / m·K.

[0088] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for preparing an out-of-plane high thermal conductivity carbon fiber composite material, characterized in that: The method comprises the following preparation steps: 1) placing carbon fibers in an electrodeposition solution for electrodeposition treatment, and then performing a reduction treatment to obtain composite carbon fibers, and weaving the composite carbon fibers to obtain a unidirectional fabric; 2) activating the thermally conductive filler and mixing it with a reactive diluent to obtain a thermally conductive slurry; 3) mixing the thermal conductive slurry, the epoxy resin curing agent and the epoxy resin to obtain a mixed slurry; 4) The mixed slurry is applied to the surface of the unidirectional fabric and then cured to obtain a composite material.

2. The method for preparing an out-of-plane high thermal conductivity carbon fiber composite material according to claim 1, characterized in that: In the step 1), the electrodeposition solution is composed of the following components in parts by mass: 190-210 parts of nickel chloride, 35-45 parts of nickel sulfate, 25-35 parts of boric acid, 0.3-0.7 parts of sodium sulfamate, 15-20 parts of sodium lauryl sulfate, 5-15 parts of graphene oxide and 675-730 parts of water.

3. The method for preparing an out-of-plane high thermal conductivity carbon fiber composite material according to claim 2, characterized in that: In the step 1), during the electrodeposition treatment, the cathode is connected to graphite, the anode is connected to the nickel block, the temperature of the electrodeposition solution is 50-60° C., and the current intensity is 0.1-0.2 A / cm 2 The electrodeposition treatment time is 45 to 60 seconds.

4. The method for preparing an out-of-plane high thermal conductivity carbon fiber composite material according to claim 2 or 3, characterized in that: In the step 1), the reduction treatment is carried out in a nitrogen atmosphere, the reduction treatment temperature is 800-1200° C., and the reduction treatment time is 2-4 minutes; The density of the unidirectional fabric is 180-220 g / m 2 .

5. The method for preparing an out-of-plane high thermal conductivity carbon fiber composite material according to claim 4, characterized in that: In the step 2), the activation time is 10 to 15 minutes, and the activation pressure is 15 to 20 Pa; The thermally conductive filler is dendritic graphene and / or amino-modified carbon nanotubes; The active diluent is butyl glycidyl ether or phenyl glycidyl ether.

6. The method for preparing an out-of-plane high thermal conductivity carbon fiber composite material according to claim 5, characterized in that: In the step 2), the mass ratio of the thermal conductive filler to the active diluent is 1:4.5-6.5; The mixing time is 60 to 110 minutes, and the mixing temperature is 70 to 90°C.

7. The method for preparing an out-of-plane high thermal conductivity carbon fiber composite material according to claim 1, characterized in that: In step 3), the specific steps of mixing the thermal conductive paste, epoxy resin curing agent and epoxy resin are: first mixing the thermal conductive paste and epoxy resin curing agent to obtain a dispersion, and then mixing the dispersion with the epoxy resin for a second time to obtain a mixed paste; The mass ratio of the thermal conductive paste to the epoxy resin curing agent is 1:2-4, and the mass ratio of the dispersion to the epoxy resin is 25-35:100; The primary mixing is ultrasonic mixing, the ultrasonic mixing time is 25 to 40 minutes, and the ultrasonic mixing frequency is 40 to 80 kHz; The secondary mixing is stirring mixing, the stirring mixing speed is 100-500 rpm, and the stirring mixing time is 3-10 minutes.

8. The method for preparing an out-of-plane high thermal conductivity carbon fiber composite material according to claim 7, characterized in that: In the step 4), curing is performed in a vacuum state with power on, the vacuum degree is ≥-0.095 MPa, and the power on voltage is 75-85V.

9. The method for preparing an out-of-plane high thermal conductivity carbon fiber composite material according to claim 8, characterized in that: In the step 4), the curing includes a first curing and a second curing, wherein the temperature of the first curing is 80-95° C. and the time of the first curing is 25-35 minutes, and the temperature of the second curing is 120-140° C. and the time of the second curing is 100-130 minutes.

10. An out-of-plane high thermal conductivity carbon fiber composite material obtained by the method for preparing an out-of-plane high thermal conductivity carbon fiber composite material according to any one of claims 1 to 9.

Images