Carbon nanotube grafted silicon carbon nitride-carbon fiber / phenolic resin composite material and preparation method thereof

Abstract

The application discloses a carbon nanotube grafted silicon carbon nitride-carbon fiber / phenolic resin composite material and a preparation method thereof, and comprises the following steps: introducing a silicon carbon nitride shell layer on the surface of carbon fiber, and then growing radial carbon nanotubes by using a catalytic chemical deposition method to obtain the carbon nanotube grafted silicon carbon nitride-carbon fiber / phenolic resin composite material. The method can make the carbon nanotubes on the carbon fiber have high density and be uniformly distributed, and the strength of the material is relatively high.

Description

TECHNICAL FIELD

[0001] The present application relates to a silicon carbon nitride-carbon fiber composite material and a preparation method thereof, in particular to a carbon nanotube grafted silicon carbon nitride-carbon fiber / phenolic resin composite material and a preparation method thereof. BACKGROUND

[0002] Carbon fiber / phenolic resin composite materials are widely used in the field of electromagnetic shielding due to their light weight, high strength, corrosion resistance, easy processing and many other characteristics. However, the electromagnetic shielding efficiency of carbon fiber / phenolic resin composite materials is greatly limited due to the low electrical conductivity of phenolic resin. In addition, due to the chemical inertness and smoothness of the carbon fiber surface, the carbon fiber and the phenolic resin are prone to debonding. During the use of the composite material, stress concentration occurs due to external force, resulting in matrix cracking and composite material damage. If the electromagnetic shielding material is broken, worn or aged during use, its electromagnetic interference shielding performance will be greatly reduced. Therefore, how to simultaneously improve the mechanical properties and electromagnetic shielding efficiency of carbon fiber / phenolic resin composite materials is worth studying.

[0003] Generally, the interface strength of electromagnetic shielding materials can be improved by introducing nano fillers. Carbon nanotubes are often used as conductive fillers in electromagnetic shielding materials due to their light weight, high strength, high aspect ratio and high thermal conductivity. However, there are often problems in the process of introducing carbon nanotubes into carbon fiber / phenolic resin composite materials by catalytic chemical deposition method. The metal catalyst is easy to react with carbon and diffuse at high temperature, losing catalytic activity. The carbonaceous surface has weak ability to capture and fix metal catalysts, and the loaded metal particles are easy to move and agglomerate. Therefore, the growth quality of carbon nanotubes on the surface of carbon fiber by catalytic chemical deposition method is poor, mainly manifested as curling, disordered orientation and low density of nanotubes. Agglomeration will lead to poor polarization loss and poor impedance matching, resulting in poor absorption capacity. Therefore, how to introduce high-density and uniformly distributed carbon nanotubes into carbon fiber / phenolic resin composite materials is worth further studying.

[0004] Document 1“Hui Qian, Alexander Bismarck, Emile S. Greenhalgh, Gerhard Kalinka, Milo S. P. Shaffer. Hierarchical composites reinforced with carbon nanotube grafted fibers: the potential assessed at the single fiber level. Chemistry of Materials, 2008, 20(5): 1862-1869.” reported that curved carbon nanotubes were grown on the surface of carbon fibers, and the tensile strength of the composite material was improved by about 26%.

[0005] Document 2“Chao Chang, Xiu Yue, Bin Hao, Dan Xing, Peng-Cheng Ma. Improvement of the electromagnetic shielding properties of C / SiC composites by electrophoretic deposition of carbon nanotube on carbon fibers. Carbon, 2016, 109: 149-153.” reported that carbon nanotubes were introduced into carbon fiber reinforced silicon carbide composites by electrophoretic deposition, and the carbon nanotubes showed a network structure. When the sample thickness was 3mm, the electromagnetic shielding effectiveness reached 38.2dB.

[0006] Document 3“Qiang Song, Kezhi Li, Hailiang Li, Hejun Li, Chang Ren. Grafting straight carbon nanotubes radially onto carbon fibers and their effect on the mechanical properties of carbon / carbon composites. Carbon, 2012, 50(10): 3949-3952.” reported that straight carbon nanotubes were prepared on the surface of carbon fibers, and the carbon fibers were treated with strong acid for 24 hours. The carbon fibers were damaged and the density of carbon nanotubes was low.

[0007] However, the carbon nanotubes reported in the above documents are difficult to be distributed at high density and uniformly on the carbon fibers, and the strong acid treatment process can seriously damage the surface structure of the carbon fibers, causing significant reduction of the fiber strength. Thus, it is difficult to introduce high-density and uniformly distributed carbon nanotubes in the composite material without damaging the carbon fibers. SUMMARY

[0008] The present application aims to overcome the above-mentioned shortcomings of the prior art, and provides a carbon nanotube grafted silicon carbon nitride-carbon fiber / phenolic resin composite material and a preparation method thereof, which can enable the carbon nanotubes to be distributed at high density and uniformly on the carbon fibers, and the material has high strength.

[0009] To achieve the above-mentioned purpose, the present application discloses a preparation method of a carbon nanotube grafted silicon carbon nitride-carbon fiber / phenolic resin composite material, comprising the following steps: introducing a silicon carbon nitride shell layer on the surface of the carbon fiber, and then growing radial carbon nanotubes using a catalytic chemical deposition method to obtain the carbon nanotube grafted silicon carbon nitride-carbon fiber / phenolic resin composite material.

[0010] Further, the method specifically comprises the following steps:

[0011] 1) Put the carbon fiber cloth into a chemical vapor deposition furnace, then heat it, and then use natural gas as the carbon source gas and argon as the protective gas to perform heat preservation, to obtain sample A;

[0012] 2) Mix polysilazane and acetone uniformly to obtain solution B;

[0013] 3) Immerse sample A in solution B, and then place it at room temperature to obtain sample C;

[0014] 4) Place sample C in a tubular heat treatment furnace, heat it, and then heat preserve it, and then take out the sample after the temperature in the tubular heat treatment furnace cools down to room temperature, to obtain sample D;

[0015] 5) Mix ferrocene, anhydrous ethanol and ferrocene uniformly to obtain solution E;

[0016] 6) Place sample D in a tubular chemical vapor deposition furnace, heat it, inject solution E into the tubular chemical vapor deposition furnace, and then take out the sample after the temperature in the tubular chemical vapor deposition furnace cools down to room temperature, to obtain sample F;

[0017] 7) Mix phenolic resin powder and anhydrous ethanol uniformly to obtain solution G;

[0018] 8) Immerse sample F in solution G, and then take it out to perform drying, and then place it at room temperature to obtain sample H;

[0019] 9) Perform heat pressing and curing on sample H to obtain the carbon nanotube grafted silicon carbon nitride-carbon fiber / phenolic resin composite material.

[0020] Further, the process of step 1) is as follows:

[0021] The carbon fiber cloth is placed in a chemical vapor deposition furnace, heated to 1000-1100 DEG C, natural gas is used as carbon source gas, the flow rate is 0.8-1 L / min, argon is used as protective gas, the flow rate is 2.0-2.4 L / min, and heat preservation is carried out for 2-4 hours to obtain sample A.

[0022] Further, in step 2), the mass ratio of polysilazane to acetone is 1:4-1:6.

[0023] In step 7), the mass ratio of phenolic resin powder to anhydrous ethanol is 1:3-1:2.

[0024] Further, in step 5), the mass ratio of ferrocene to anhydrous ethanol is 1:80-1:100, and the mass ratio of ferrocene to ethylenediamine is 1:15-1:18.

[0025] Further, the process of step 4) is as follows: sample C is placed in a tubular heat treatment furnace, heated to 150-300 DEG C and heat preserved for 2-3 hours, then heated to 800-950 DEG C and heat preserved for 2-3 hours, wherein the heating rate is 2.5-5 DEG C / min, the sample is taken out after the temperature in the tubular heat treatment furnace cools to room temperature, and sample D is obtained.

[0026] Further, the process of step 6) is as follows: sample D is placed in a tubular chemical vapor deposition furnace, heated to 800-900 DEG C, solution E is injected into the tubular chemical vapor deposition furnace at a speed of 5-15 ml / h, the injection time is 10-30 minutes, the sample is taken out after the temperature in the tubular chemical vapor deposition furnace cools to room temperature, and sample F is obtained.

[0027] Further, the process of step 8) is as follows: sample F is soaked in solution G for 1-3 days, then taken out and placed in an oven, heated and heat preserved, and then placed at room temperature for 1-3 days to obtain sample H.

[0028] Further, the process of step 9) is as follows: sample H is placed on a flat plate heat press at 150-165 DEG C and heat pressed and solidified for 200-400 seconds to obtain a carbon nanotube grafted silicon carbonitride-carbon fiber / phenolic resin composite material.

[0029] The carbon nanotube grafted silicon carbonitride-carbon fiber / phenolic resin composite material is prepared by the preparation method of the carbon nanotube grafted silicon carbonitride-carbon fiber / phenolic resin composite material.

[0030] The present application has the following beneficial effects:

[0031] The carbon nanotube grafted silicon carbon nitride-carbon fiber / phenolic resin composite material and the preparation method thereof have the advantages that a silicon carbon nitride shell is introduced on the carbon fiber, and through the design of the process steps, high-density and uniformly distributed radial carbon nanotubes are introduced into the carbon fiber / phenolic resin composite material. It should be noted that the highest strength of the carbon fiber / phenolic resin composite material prepared by the present application is 161.28 MPa, and when the thickness is 0.4 mm, the electromagnetic shielding effectiveness is 40.73 dB. At the same time, the present application realizes the high-density and uniform distribution of radial carbon nanotubes in the carbon fiber / phenolic resin composite material, and the carbon fiber is not damaged in the preparation process. The reason for the strength improvement is that the radial carbon nanotubes at the fiber / matrix interface increase the bonding force between the carbon fiber and the matrix, and in addition, the radial carbon nanotubes penetrate into the interior of the matrix, and under the action of external force, can effectively hinder the matrix cracking phenomenon caused by crack propagation. The reason for the improvement of the electromagnetic shielding effectiveness is that the electromagnetic wave will be reflected and scattered multiple times when passing through the radial carbon nanotubes, causing a large amount of energy loss. In addition, the addition of radial carbon nanotubes improves the electrical conductivity of the sample, increases the conduction loss, and improves the reflection efficiency of the electromagnetic wave. BRIEF DESCRIPTION OF DRAWINGS

[0032] The accompanying drawings, which form a part of the present description, are used to provide further understanding of the present application, and the illustrative embodiments of the present application and their description serve to explain the present application. The present description is not intended to be an undue limitation on the application and the scope thereof. In the drawings:

[0033] Figure 1 A scanning electron microscope photo of the radial carbon nanotube grafted silicon carbon nitride-carbon fiber prepared in Example One;

[0034] Figure 2 Another scanning electron microscope photo of the radial carbon nanotube grafted silicon carbon nitride-carbon fiber prepared in Example One.

[0035] Figure 3 Another scanning electron microscope photo of the radial carbon nanotube grafted silicon carbon nitride-carbon fiber prepared in Example One.

[0036] Figure 4 A scanning electron microscope photo of the silicon carbon nitride-carbon fiber prepared in step 4) of Example Four;

[0037] Figure 5 A scanning electron microscope photo of the radial carbon nanotube grafted silicon carbon nitride-carbon fiber prepared in step 6) of Example Four.

[0038] Figure 6 Another scanning electron microscope photo of the silicon carbon nitride-carbon fiber prepared in step 4) of Example Four;

[0039] Figure 7 Another SEM image of the radial carbon nanotube grafted silicon carbon nitride-carbon fiber prepared in step 6) of Example 4.

[0040] Figure 8 Tensile property test graph of the material obtained in Example 1 and Example 4;

[0041] Figure 9 Electromagnetic shielding test graph of the material obtained in Example 1 and Example 4. DETAILED DESCRIPTION

[0042] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0043] In the description of the present application, it should be understood that the terms "comprise" and "include" indicate the presence of described features, integers, steps, operations, elements, and / or components, but do not exclude one or more other features, integers, steps, operations, elements, components, and / or sets thereof.

[0044] It should also be understood that the terms used in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. As used in the specification and the appended claims of the present application, the singular forms "a", "an" and "the" are intended to include the plural forms unless the context clearly indicates otherwise.

[0045] It should be further understood that the term "and / or" used in the specification and the appended claims of the present application means any combination of one or more of the associated listed items and all possible combinations thereof, and includes these combinations, for example, A and / or B can represent three cases of A alone, A and B together, and B alone. In addition, the character " / " in the present application generally represents an "or" relationship between the front and rear associated objects.

[0046] It should be understood that although the terms first, second, third, etc. may be used in the embodiments of the present application to describe the preset ranges, etc., these preset ranges should not be limited to these terms. These terms are only used to distinguish the preset ranges from each other. For example, the first preset range can also be referred to as the second preset range, and similarly, the second preset range can also be referred to as the first preset range without departing from the scope of the embodiments of the present application.

[0047] Depending on the context, the word "if" as used herein can be interpreted to mean "when" or "while" or "in response to determining" or "in response to detecting." Similarly, the phrase "if it is determined" or "if [a stated condition or event] is detected" can be interpreted to mean "when it is determined" or "in response to determining" or "when [a stated condition or event] is detected" or "in response to detecting [a stated condition or event]."

[0048] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the following will be combined with the drawings in the embodiments of the present application to make a clear and complete description of the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed present application, but only represents selected embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art without creative efforts based on the embodiments in the present application belong to the scope of protection of the present application.

[0049] Various structural schematic diagrams according to the disclosed embodiments of the present application are shown in the drawings. These diagrams are not drawn to scale, in which some details are exaggerated for the purpose of clear expression, and some details can be omitted. The shapes of various regions, layers and their relative sizes and positional relationships shown in the drawings are only exemplary, and in actuality, there can be deviations due to manufacturing tolerances or technical limitations, and regions / layers with different shapes, sizes and relative positions can be additionally designed by those skilled in the art according to actual needs.

[0050] The preparation method of the carbon nanotube grafted silicon carbonitride-carbon fiber / phenolic resin composite material described in the present application comprises the following steps:

[0051] 1) Put the carbon fiber cloth into a chemical vapor deposition furnace, heat to 1000-1100℃, use natural gas as carbon source gas, the flow rate is 0.8-1L / min, use argon as protective gas, the flow rate is 2.0-2.4L / min, keep warm for 2-4 hours, to obtain sample A.

[0052] 2) Mix polysilazane and acetone uniformly to obtain solution B, wherein the mass ratio of polysilazane to acetone is 1:4-1:6.

[0053] 3) Soak sample A in solution B for 5-10 minutes, then place it at room temperature for 24-48 hours to obtain sample C.

[0054] 4) Put sample C into a tube heat treatment furnace, heat to 150-300℃ and keep for 2-3 hours, then heat to 800-950℃ and keep for 2-3 hours, wherein the heating rate is 2.5-5℃ / min, take out the sample after the temperature in the tube heat treatment furnace cools to room temperature, and obtain sample D.

[0055] 5) Mix ferrocene, anhydrous ethanol and ferrocene uniformly to obtain solution E, wherein the mass ratio of ferrocene to anhydrous ethanol is 1:80-1:100, and the mass ratio of ferrocene to ethylenediamine is 1:15-1:18.

[0056] 6) Put sample D into a tube chemical vapor deposition furnace, heat to 800-900℃, inject solution E into the tube chemical vapor deposition furnace at a speed of 5-15ml / h, the injection time is 10-30 minutes, take out the sample after the temperature in the tube chemical vapor deposition furnace cools to room temperature, and obtain sample F.

[0057] 7) Mix phenolic resin powder and anhydrous ethanol uniformly to obtain solution G, and the mass ratio of phenolic resin powder to anhydrous ethanol is 1:3-1:2.

[0058] 8) Put sample F into solution G and soak for 1-3 days, take out and place in an oven, then keep at 70℃ for 10 minutes, and then place at room temperature for 1-3 days, and obtain sample H.

[0059] 9) Put sample H on a flat plate heat press at 150-165℃ and heat press and solidify for 200-400 seconds, and obtain carbon nanotube grafted silicon carbon nitrogen-carbon fiber / phenolic resin composite material.

[0060] Example One

[0061] This example includes the following steps:

[0062] 1) Put carbon fiber cloth into a chemical vapor deposition furnace, heat to 1000℃, use natural gas as carbon source gas, the flow rate is 0.8L / min, use argon as protective gas, the flow rate is 2.0L / min, keep for 4 hours, and obtain sample A.

[0063] 2) Mix polysilazane and acetone uniformly to obtain solution B, and the mass ratio of polysilazane to acetone is 1:6.

[0064] 3) Soak sample A in solution B for 10 minutes, and then place at room temperature for 24 hours, and obtain sample C.

[0065] 4) Put sample C into a tube heat treatment furnace, heat to 300℃ and keep for 2 hours, then heat to 800℃ and keep for 3 hours, wherein the heating rate is 2.5℃ / min, take out the sample after the temperature in the tube heat treatment furnace cools to room temperature, and obtain sample D.

[0066] 5) Mix ferrocene, anhydrous ethanol and ferrocene uniformly to obtain solution E, wherein the mass ratio of ferrocene to anhydrous ethanol is 1:80, and the mass ratio of ferrocene to ethylenediamine is 1:15.

[0067] 6) Put sample D into a tube chemical vapor deposition furnace, heat to 800℃, inject solution E into the tube chemical vapor deposition furnace at a speed of 5ml / h, the injection time is 30 minutes, take out the sample after the temperature in the tube chemical vapor deposition furnace cools to room temperature, and obtain sample F.

[0068] 7) Mix phenolic resin powder and anhydrous ethanol uniformly to obtain solution G, and the mass ratio of phenolic resin powder to anhydrous ethanol is 1:3.

[0069] 8) Put sample F into solution G and soak for 3 days, then take out and place in an oven, keep at 70℃ for 10 minutes, then place at room temperature for 3 days, and obtain sample H.

[0070] 9) Put sample H on a flat plate hot press at 165℃ and hot press for 200 seconds to obtain carbon nanotube grafted silicon carbon nitrogen-carbon fiber / phenolic resin composite material.

[0071] Example Two

[0072] This example includes the following steps:

[0073] 1) Put carbon fiber cloth into a chemical vapor deposition furnace, heat to 1100℃, use natural gas as carbon source gas, the flow rate is 1L / min, use argon as protective gas, the flow rate is 2.4L / min, keep for 2 hours, and obtain sample A.

[0074] 2) Mix polysilazane and acetone uniformly to obtain solution B, wherein the mass ratio of polysilazane to acetone is 1:4.

[0075] 3) Soak sample A in solution B for 10 minutes, then place at room temperature for 48 hours, and obtain sample C.

[0076] 4) Put sample C into a tube heat treatment furnace, heat to 300℃ and keep for 3 hours, then heat to 950℃ and keep for 3 hours, wherein the heating rate is 5℃ / min, take out the sample after the temperature in the tube heat treatment furnace cools to room temperature, and obtain sample D.

[0077] 5) Ferrocene, anhydrous ethanol and ferrocene were uniformly mixed to obtain solution E, wherein the mass ratio of ferrocene to anhydrous ethanol was 1:80, and the mass ratio of ferrocene to ethylenediamine was 1:15.

[0078] 6) Sample D was placed in a tube-type chemical vapor deposition furnace and heated to 800°C, and solution E was injected into the tube-type chemical vapor deposition furnace at a speed of 5 ml / h for 10 minutes. After the temperature in the tube-type chemical vapor deposition furnace cooled to room temperature, the sample was taken out to obtain sample F.

[0079] 7) Phenolic resin powder and anhydrous ethanol were uniformly mixed to obtain solution G, and the mass ratio of phenolic resin powder to anhydrous ethanol was 1:3.

[0080] 8) Sample F was soaked in solution G for 1 day, and then taken out and placed in an oven for 10 minutes at 70°C, and then placed at room temperature for 1 day to obtain sample H.

[0081] 9) Sample H was placed in a flat plate hot press at 150°C for 200 seconds to obtain a carbon nanotube grafted silicon carbon nitrogen-carbon fiber / phenolic resin composite material.

[0082] Example Three

[0083] This example includes the following steps:

[0084] 1) Carbon fiber cloth was placed in a chemical vapor deposition furnace and heated to 1100°C, natural gas was used as the carbon source gas with a flow rate of 0.8 L / min, and argon was used as the protective gas with a flow rate of 2.0 L / min, and the temperature was maintained for 4 hours to obtain sample A.

[0085] 2) Polysilazane and acetone were uniformly mixed to obtain solution B, and the mass ratio of polysilazane to acetone was 1:4.

[0086] 3) Sample A was immersed in solution B for 5 minutes and then placed at room temperature for 48 hours to obtain sample C.

[0087] 4) Sample C was placed in a tube-type heat treatment furnace and heated to 150°C for 3 hours, and then heated to 800°C for 3 hours, wherein the heating rate was 2.5°C / min, and the sample was taken out after the temperature in the tube-type heat treatment furnace cooled to room temperature to obtain sample D.

[0088] 5) Ferrocene, anhydrous ethanol and ferrocene were uniformly mixed to obtain solution E, wherein the mass ratio of ferrocene to anhydrous ethanol was 1:100, and the mass ratio of ferrocene to ethylenediamine was 1:15.

[0089] 6) Put sample D into a tube type chemical vapor deposition furnace, heat to 900℃, inject solution E into the tube type chemical vapor deposition furnace at a speed of 5ml / h, the injection time is 30 minutes, take out the sample after the temperature in the tube type chemical vapor deposition furnace cools to room temperature, to obtain sample F.

[0090] 7) Mix phenolic resin powder and anhydrous ethanol uniformly to obtain solution G, the mass ratio of phenolic resin powder to anhydrous ethanol is 1:3.

[0091] 8) Put sample F into solution G and soak for 3 days, take out and place in an oven, heat at 70℃ for 10 minutes, then place at room temperature for 1 day, to obtain sample H.

[0092] 9) Put sample H on a flat plate hot press at 165℃ and heat press for 200 seconds, to obtain carbon nanotube grafted silicon carbon nitrogen-carbon fiber / phenolic resin composite material.

[0093] Example Four

[0094] This example includes the following steps:

[0095] 1) Put carbon fiber cloth into a chemical vapor deposition furnace, heat to 1000℃, argon as protective gas, flow rate is 2.0-2.4L / min, heat for 2 hours, to obtain sample A.

[0096] 2) Mix polysilazane and acetone uniformly at a mass ratio of 1:4 to obtain solution B.

[0097] 3) Soak sample A in solution B for 10 minutes, then place at room temperature for 48 hours, to obtain sample C.

[0098] 4) Put sample C into a tube type heat treatment furnace, heat to 150℃ and heat for 2 hours, then heat to 950℃ and heat for 2 hours, the heating rate is 5℃ / min, take out the sample after the temperature in the furnace cools to room temperature, to obtain sample D.

[0099] 5) Mix ferrocene, anhydrous ethanol and ferrocene uniformly, wherein the mass ratio of ferrocene to anhydrous ethanol is 1:80, the mass ratio of ferrocene to ethylenediamine is 1:18, stir uniformly to obtain solution E.

[0100] 6) Put sample D into a tube type chemical vapor deposition furnace, heat to 800℃, inject solution E into the tube type chemical vapor deposition furnace at a speed of 15ml / h, the injection time is 10 minutes, take out the sample after the temperature in the furnace cools to room temperature, to obtain sample F.

[0101] 7) Mix phenolic resin powder and anhydrous ethanol uniformly at a mass ratio of 1:2, stir uniformly to obtain solution G.

[0102] 8) Put sample F into solution G for 1 day, and then put it into the oven for 10 minutes at 70℃, and then put it at room temperature for 3 days to obtain sample H.

[0103] 9) Put sample H into a flat hot press at 150℃ for 200 seconds to obtain carbon nanotube grafted silicon carbonitride-carbon fiber / phenolic resin composite material.

[0104] In this example four, since no pyrolytic carbon shell is deposited in step), the silicon carbonitride core-shell on the surface of the carbon fiber is cracked, and thus the carbon nanotubes with high density and uniform distribution cannot be obtained, and the material strength is only 82 MPa, and the average electromagnetic shielding effectiveness in X band is only 16.19 dB.

[0105] Reference Figure 8 and Figure 9 If the deposition of pyrolytic carbon in step 1) is not required, due to the large difference in elastic modulus between silicon carbonitride and carbon fiber, the silicon carbonitride core-shell on the surface of the carbon fiber is cracked, and thus the carbon nanotubes with high density and uniform distribution cannot be obtained. If the solution ratio requirement in step 2) is not met, the content of silicon carbonitride in the carbon fiber is too large, and cracking occurs during temperature rising and falling, and thus the carbon nanotubes with high density and uniform distribution cannot be obtained. By comparing the force-displacement curves of comparative example one and example four, it can be seen that the tensile strength of example one is 96.34% higher than that of example four. It proves that the carbon nanotubes with high density and uniform distribution have a significant effect on the enhancement of the carbon fiber / phenolic resin composite material. By comparing the electromagnetic shielding effectiveness curves of comparative example one and example four, it can be seen that the average electromagnetic shielding effectiveness of example one reaches 40.73 dB, which is 151.73% higher than that of example four. It proves that the carbon nanotubes with high density and uniform distribution have a significant effect on the electromagnetic shielding capacity of the carbon fiber / phenolic resin composite material.

[0106] Example five

[0107] This example includes the following steps:

[0108] 1) Put the carbon fiber cloth into the chemical vapor deposition furnace, heat it to 1000℃, use natural gas as the carbon source gas with a flow rate of 1 L / min, and use argon as the protective gas with a flow rate of 2.0 L / min, and keep it for 4 hours to obtain sample A.

[0109] 2) Mix polysilazane and acetone uniformly at a mass ratio of 4:1 to obtain solution B.

[0110] 3) Soak sample A in solution B for 5 minutes, and then put it at room temperature for 48 hours to obtain sample C.

[0111] 4) Put sample C into a tube heat treatment furnace, heat to 150℃ for 3 hours, then heat to 800℃ for 3 hours, the heating rate is 2.5℃ / min, take out the sample after the furnace temperature cools to room temperature, to obtain sample D.

[0112] 5) Mix ferrocene, anhydrous ethanol and ferrocene uniformly, stir uniformly to obtain solution E, wherein the mass ratio of ferrocene to anhydrous ethanol is 1:100, and the mass ratio of ferrocene to ethylenediamine is 1:15.

[0113] 6) Put sample D into a tube chemical vapor deposition furnace, heat to 900℃, inject solution E into the tube chemical vapor deposition furnace at a speed of 5ml / h, the injection time is 30 minutes, take out the sample after the furnace temperature cools to room temperature, to obtain sample F.

[0114] 7) Mix phenolic resin powder and anhydrous ethanol uniformly at a mass ratio of 1:3, stir uniformly to obtain solution G.

[0115] 8) Put sample F into solution G and soak for 3 days, then take out and place in an oven, heat at 70℃ for 10 minutes, then place at room temperature for 1 day, to obtain sample H.

[0116] 9) Put sample H on a flat plate hot press at 165℃ and hot press for 200 seconds to obtain carbon nanotube grafted silicon carbonitride-carbon fiber / phenolic resin composite material.

[0117] In this embodiment five, due to the preparation process does not meet the solution ratio requirements in step 2), which will lead to the content of silicon carbonitride in the carbon fiber being too large, cracking occurs during temperature rising and falling, and the carbon nanotubes with radial high density and uniform distribution cannot be obtained.

[0118] Example six

[0119] The preparation method of the carbon nanotube grafted silicon carbonitride-carbon fiber / phenolic resin composite material comprises the following steps:

[0120] 1) Put the carbon fiber cloth into a chemical vapor deposition furnace, heat to 1000℃, use natural gas as carbon source gas, the flow rate is 0.8L / min, use argon as protective gas, the flow rate is 2.0L / min, heat for 2 hours, to obtain sample A.

[0121] 2) Mix polysilazane and acetone uniformly to obtain solution B, wherein the mass ratio of polysilazane to acetone is 1:4.

[0122] 3) Soak sample A in solution B for 5 minutes, then place at room temperature for 24 hours to obtain sample C.

[0123] 4) Put sample C into a tube heat treatment furnace, heat to 150℃ and keep for 2 hours, then heat to 800℃ and keep for 2 hours, wherein the heating rate is 2.5℃ / min, take out the sample after the temperature in the tube heat treatment furnace cools to room temperature, and obtain sample D.

[0124] 5) Mix ferrocene, anhydrous ethanol and ferrocene uniformly to obtain solution E, wherein the mass ratio of ferrocene to anhydrous ethanol is 1:80, and the mass ratio of ferrocene to ethylenediamine is 1:15.

[0125] 6) Put sample D into a tube chemical vapor deposition furnace, heat to 800℃, inject solution E into the tube chemical vapor deposition furnace at a speed of 5ml / h, the injection time is 10 minutes, take out the sample after the temperature in the tube chemical vapor deposition furnace cools to room temperature, and obtain sample F.

[0126] 7) Mix phenolic resin powder and anhydrous ethanol uniformly to obtain solution G, and the mass ratio of phenolic resin powder to anhydrous ethanol is 1:3.

[0127] 8) Put sample F into solution G and soak for 1 day, then take out and place in an oven, keep for 10 minutes at 70℃, and then place at room temperature for 1 day, and obtain sample H.

[0128] 9) Put sample H on a flat plate heat press at 150℃ and heat press and solidify for 200 seconds, and obtain carbon nanotube grafted silicon carbonitride-carbon fiber / phenolic resin composite material.

[0129] Example Seven

[0130] The preparation method of the carbon nanotube grafted silicon carbonitride-carbon fiber / phenolic resin composite material comprises the following steps:

[0131] 1) Put carbon fiber cloth into a chemical vapor deposition furnace, heat to 1100℃, use natural gas as carbon source gas with a flow rate of 1L / min, and use argon as protective gas with a flow rate of 2.4L / min, and keep for 4 hours, and obtain sample A.

[0132] 2) Mix polysilazane and acetone uniformly to obtain solution B, wherein the mass ratio of polysilazane to acetone is 1:6.

[0133] 3) Soak sample A in solution B for 10 minutes, and then place at room temperature for 48 hours, and obtain sample C.

[0134] 4) Put sample C into a tube heat treatment furnace, heat to 300℃ and keep for 3 hours, then heat to 950℃ and keep for 3 hours, wherein the heating rate is 5℃ / min, take out the sample after the temperature in the tube heat treatment furnace cools to room temperature, and obtain sample D.

[0135] 5) Ferrocene, absolute ethanol and ferrocene were uniformly mixed to obtain solution E, wherein the mass ratio of ferrocene to absolute ethanol was 1:100, and the mass ratio of ferrocene to ethylenediamine was 1:18.

[0136] 6) Sample D was placed in a tube chemical vapor deposition furnace and heated to 900℃, solution E was injected into the tube chemical vapor deposition furnace at a speed of 15ml / h, the injection time was 30 minutes, and sample F was obtained after the temperature in the tube chemical vapor deposition furnace cooled to room temperature.

[0137] 7) Phenolic resin powder and absolute ethanol were uniformly mixed to obtain solution G, and the mass ratio of phenolic resin powder to absolute ethanol was 1:2.

[0138] 8) Sample F was soaked in solution G for 3 days, and then placed in an oven after being taken out, and then incubated at 70℃ for 10 minutes, and then placed at room temperature for 3 days to obtain sample H.

[0139] 9) Sample H was placed on a flat plate hot press at 165℃ for heat pressing and curing for 400 seconds to obtain a carbon nanotube grafted silicon carbon nitride-carbon fiber / phenolic resin composite material.

[0140] Example Eight

[0141] The preparation method of the carbon nanotube grafted silicon carbon nitride-carbon fiber / phenolic resin composite material comprises the following steps:

[0142] 1) Carbon fiber cloth was placed in a chemical vapor deposition furnace and heated to 1050℃, natural gas was used as carbon source gas with a flow rate of 0.9L / min, and argon was used as protective gas with a flow rate of 2.2L / min, and incubated for 3 hours to obtain sample A.

[0143] 2) Polysilazane and acetone were uniformly mixed to obtain solution B, wherein the mass ratio of polysilazane to acetone was 1:5.

[0144] 3) Sample A was immersed in solution B for 7.5 minutes, and then placed at room temperature for 26 hours to obtain sample C.

[0145] 4) Sample C was placed in a tube heat treatment furnace, heated to 220℃ and incubated for 2.5 hours, and then heated to 870℃ and incubated for 2.5 hours, wherein the heating rate was 3.5℃ / min, and sample D was obtained after the temperature in the tube heat treatment furnace cooled to room temperature.

[0146] 5) Ferrocene, absolute ethanol and ferrocene were uniformly mixed to obtain solution E, wherein the mass ratio of ferrocene to absolute ethanol was 1:90, and the mass ratio of ferrocene to ethylenediamine was 1:16.5.

[0147] 6) Put sample D into a tube type chemical vapor deposition furnace, heat to 850℃, inject solution E into the tube type chemical vapor deposition furnace at a speed of 10ml / h, the injection time is 20 minutes, take out the sample after the temperature in the tube type chemical vapor deposition furnace cools to room temperature, to obtain sample F.

[0148] 7) Mix phenolic resin powder and anhydrous ethanol uniformly to obtain solution G, the mass ratio of phenolic resin powder to anhydrous ethanol is 1:2.5.

[0149] 8) Put sample F into solution G and soak for 2 days, take out and place in an oven, heat at 70℃ for 10 minutes, then place at room temperature for 2 days, to obtain sample H.

[0150] 9) Put sample H on a flat plate hot press at 158℃ and heat press for 300 seconds, to obtain carbon nanotube grafted silicon carbon nitride-carbon fiber / phenolic resin composite material.

[0151] Example Nine

[0152] The preparation method of the carbon nanotube grafted silicon carbon nitride-carbon fiber / phenolic resin composite material comprises the following steps:

[0153] 1) Put carbon fiber cloth into a chemical vapor deposition furnace, heat to 1040℃, use natural gas as carbon source gas, the flow rate is 0.85L / min, use argon as protective gas, the flow rate is 2.1L / min, heat for 2.5 hours, to obtain sample A.

[0154] 2) Mix polysilazane and acetone uniformly to obtain solution B, wherein the mass ratio of polysilazane to acetone is 1:4.5.

[0155] 3) Soak sample A in solution B for 6 minutes, then place at room temperature for 25 hours, to obtain sample C.

[0156] 4) Put sample C into a tube type heat treatment furnace, heat to 180℃ and heat for 2.2 hours, then heat to 850℃ and heat for 2.2 hours, wherein the heating rate is 2.8℃ / min, take out the sample after the temperature in the tube type heat treatment furnace cools to room temperature, to obtain sample D.

[0157] 5) Mix ferrocene, anhydrous ethanol and ferrocene uniformly to obtain solution E, wherein the mass ratio of ferrocene to anhydrous ethanol is 1:85, and the mass ratio of ferrocene to ethylenediamine is 1:16.

[0158] 6) Put sample D into a tube type chemical vapor deposition furnace, heat to 820℃, inject solution E into the tube type chemical vapor deposition furnace at a speed of 8ml / h, the injection time is 15 minutes, take out the sample after the temperature in the tube type chemical vapor deposition furnace cools to room temperature, to obtain sample F.

[0159] 7) uniformly mix the phenolic resin powder and anhydrous ethanol to obtain solution G, the mass ratio of the phenolic resin powder to anhydrous ethanol being 1:2.2.

[0160] 8) soak sample F in solution G for 1.5 days, take it out and place it in an oven, and then incubate it at 70℃ for 10 minutes, and then place it at room temperature for 1.5 days to obtain sample H.

[0161] 9) heat press and cure sample H on a flat plate heat press at 155℃ for 250 seconds to obtain a carbon nanotube grafted silicon carbonitride-carbon fiber / phenolic resin composite material.

[0162] Example Ten

[0163] The preparation method of the carbon nanotube grafted silicon carbonitride-carbon fiber / phenolic resin composite material described in the present application comprises the following steps:

[0164] 1) place a carbon fiber cloth in a chemical vapor deposition furnace, heat it to 1020℃, use natural gas as a carbon source gas with a flow rate of 0.82L / min, and use argon as a protective gas with a flow rate of 2.1L / min, and incubate it for 2.5 hours to obtain sample A.

[0165] 2) uniformly mix polysilazane and acetone to obtain solution B, wherein the mass ratio of polysilazane to acetone is 1:4.5.

[0166] 3) immerse sample A in solution B for 9 minutes, and then place it at room temperature for 27 hours to obtain sample C.

[0167] 4) place sample C in a tubular heat treatment furnace, heat it to 250℃ and incubate it for 2.8 hours, and then heat it to 900℃ and incubate it for 2.8 hours, wherein the heating rate is 4.5℃ / min, take out the sample after the temperature in the tubular heat treatment furnace cools to room temperature to obtain sample D.

[0168] 5) uniformly mix ferrocene, anhydrous ethanol and ferrocene to obtain solution E, wherein the mass ratio of ferrocene to anhydrous ethanol is 1:95, and the mass ratio of ferrocene to ethylenediamine is 1:17.

[0169] 6) place sample D in a tubular chemical vapor deposition furnace, heat it to 880℃, inject solution E into the tubular chemical vapor deposition furnace at a speed of 12ml / h for 25 minutes, and then take out the sample after the temperature in the tubular chemical vapor deposition furnace cools to room temperature to obtain sample F.

[0170] 7) uniformly mix the phenolic resin powder and anhydrous ethanol to obtain solution G, the mass ratio of the phenolic resin powder to anhydrous ethanol being 1:2.8.

[0171] 8) Sample F was soaked in solution G for 2.8 days, then placed in an oven for 10 minutes at 70 degrees Celsius, and then left at room temperature for 2.8 days to obtain sample H.

[0172] 9) Sample H was hot pressed on a flat hot press at 160 degrees Celsius for 350 seconds to obtain carbon nanotube grafted silicon carbonitride-carbon fiber / phenolic resin composite material.

[0173] Other embodiments of the application will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. It is intended that the specification and examples be considered as exemplary only, with the true scope and spirit of the application being indicated by the following claims.

[0174] It is to be understood that the application is not limited to the precise details of construction and the above-described and illustrated embodiments shown in the drawings, as the same can be modified in various ways within the scope of the application. The scope of the application is limited only by the claims that follow.

[0175] The above description is only the preferred embodiment of the present application, not any limitation to the present application, any simple modification, change and equivalent structure change of the above embodiment according to the technical essence of the present application are still within the protection scope of the technical solution of the present application.

Claims

1. A method for preparing a carbon nanotube-grafted silicon carbon nitride-carbon fiber / phenolic resin composite material, characterized in that, Includes the following steps: A silicon-carbon-nitrogen shell layer was introduced on the surface of carbon fiber, and then radial carbon nanotubes were grown using catalytic chemical deposition to obtain a carbon nanotube-grafted silicon-carbon-nitrogen-carbon fiber / phenolic resin composite material. Specifically, the following steps are included: 1) The carbon fiber cloth was placed in a chemical vapor deposition furnace and heated. Natural gas was used as the carbon source gas and argon was used as the protective gas for heat preservation to obtain sample A. 2) Mix polysilazane and acetone evenly to obtain solution B; 3) Immerse sample A in solution B and then place it at room temperature to obtain sample C; 4) Place sample C in a tubular heat treatment furnace, heat it up and keep it at that temperature. After the temperature inside the tubular heat treatment furnace cools down to room temperature, take out the sample to obtain sample D. 5) Mix ferrocene, anhydrous ethanol and ethylenediamine evenly to obtain solution E; 6) After placing sample D in a tubular chemical vapor deposition furnace and heating it, inject solution E into the tubular chemical vapor deposition furnace. After the temperature inside the tubular chemical vapor deposition furnace cools to room temperature, remove the sample to obtain sample F. 7) Phenolic resin powder is mixed evenly with anhydrous ethanol to obtain solution G; 8) Immerse sample F in solution G, remove it, dry it, and then place it at room temperature to obtain sample H; 9) Sample H was hot-pressed and cured to obtain a carbon nanotube-grafted silicon carbon nitrogen-carbon fiber / phenolic resin composite material. In step 2), the mass ratio of polysilazane to acetone is 1:4 to 1:6; In step 7), the mass ratio of phenolic resin powder to anhydrous ethanol is 1:3 to 1:

2. In step 5), the mass ratio of ferrocene to anhydrous ethanol is 1:80 to 1:100, and the mass ratio of ferrocene to ethylenediamine is 1:15 to 1:

18.

2. The method for preparing the carbon nanotube-grafted silicon carbon nitrogen-carbon fiber / phenolic resin composite material according to claim 1, characterized in that, Step 1) is as follows: Carbon fiber cloth was placed in a chemical vapor deposition furnace and heated to 1000℃~1100℃. Natural gas was used as the carbon source gas with a flow rate of 0.8 L / min~1 L / min, and argon was used as the protective gas with a flow rate of 2.0 L / min~2.4 L / min. The temperature was maintained for 2~4 hours to obtain sample A.

3. The method for preparing the carbon nanotube-grafted silicon carbon nitrogen-carbon fiber / phenolic resin composite material according to claim 2, characterized in that, Step 4) is as follows: Place sample C in a tubular heat treatment furnace, heat it to 150℃~300℃ and hold it for 2~3 hours, then heat it to 800℃~950℃ and hold it for 2~3 hours. The heating rate is 2.5℃ / min~5℃ / min. After the temperature inside the tubular heat treatment furnace cools to room temperature, take out the sample to obtain sample D.

4. The method for preparing the carbon nanotube-grafted silicon carbon nitrogen-carbon fiber / phenolic resin composite material according to claim 2, characterized in that, Step 6) is as follows: Place sample D in a tubular chemical vapor deposition furnace and heat it to 800℃~900℃. Inject solution E into the tubular chemical vapor deposition furnace at a rate of 5ml / h~15ml / h for 10~30 minutes. After the temperature inside the tubular chemical vapor deposition furnace cools to room temperature, take out the sample to obtain sample F.

5. The method for preparing the carbon nanotube-grafted silicon carbon nitrogen-carbon fiber / phenolic resin composite material according to claim 2, characterized in that, Step 8) involves immersing sample F in solution G for 1-3 days, then placing it in an oven, heating it up and keeping it warm, and finally placing it at room temperature for 1-3 days to obtain sample H.

6. The method for preparing the carbon nanotube-grafted silicon carbon nitrogen-carbon fiber / phenolic resin composite material according to claim 1, characterized in that, Step 9) involves placing sample H on a flatbed hot press at 150℃~165℃ for 200~400 seconds to cure it, thereby obtaining a carbon nanotube-grafted silicon carbon nitrogen-carbon fiber / phenolic resin composite material.

7. A carbon nanotube-grafted silicon carbon nitride-carbon fiber / phenolic resin composite material, characterized in that, It is prepared using the preparation method of carbon nanotube-grafted silicon carbon nitrogen-carbon fiber / phenolic resin composite material according to any one of claims 1-6.

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