A method for producing a carbon fiber / phenol resin composite

Abstract

The present application relates to the technical field of composite materials, and particularly relates to a preparation method of carbon fiber / phenolic resin composite material, which comprises the following steps: A, carbon fibers are placed in an organic solvent for desizing treatment; B, the carbon fibers after the desizing treatment in step A are immersed in a soaking solution containing tannic acid, octaamino cage polysilsesquioxane and attapulgite, and modified carbon fibers are obtained after drying; C, phenolic resin is dissolved in an organic solvent to prepare an impregnation solution, and the impregnation solution is coated on the modified carbon fibers in step B, and after drying, a prepreg is obtained, the prepreg is stacked in sequence, and a modified carbon fiber / phenolic resin composite material is obtained after hot pressing and curing, the composite material prepared by the present application has good interface, ablation and thermal insulation at the same time, and has a wide application prospect in the fields of aerospace and military thermal protection.

Description

Technical Field

[0001] This invention relates to the field of composite material technology, and in particular to a method for preparing a carbon fiber / phenolic resin composite material. Background Technology

[0002] Carbon fiber reinforced phenolic resin (CF / PR) composites possess advantages such as light weight, high tensile strength, high carbon yield, and good mechanical properties, making them widely used in aerospace thermal protection systems. With the increasing speed and distance of spacecraft, chemical erosion and thermal ablation caused by aerodynamic heating are becoming increasingly severe. Simultaneously, spacecraft face higher temperature environments in hypersonic operation, and thermal protection materials with high thermal conductivity can seriously affect spacecraft safety and service life. The limited ablation properties, poor interfacial properties, and high thermal conductivity of carbon fiber (CF) / phenolic resin (PR) ablation thermal protection composites restrict their further application under harsh operating conditions. Therefore, improving the performance of CF / PR composites to meet the higher thermal protection requirements of spacecraft has become a top priority.

[0003] When composite materials are exposed to high-temperature heat flux environments, the interface is the weakest point, directly affecting the stability of the composite material and the safety of the aircraft. Currently, most research focuses on carbon fiber surface treatment to improve interface properties, including chemical grafting, physical coating treatments, and chemical vapor deposition (CVD) for fiber modification. However, these modifications often only focus on the interface properties of carbon fiber composites, neglecting their ablation and thermal insulation properties. In recent years, the application of coatings that form antioxidant ceramic layers on carbon fiber fabrics to improve the ablation and thermal insulation properties of carbon fiber composites has attracted widespread attention. However, the application of inorganic coatings can lead to a deterioration in the interface properties of the composite material, resulting in a decrease in its mechanical properties. Carbon fiber composites used for load-bearing, ablation, and thermal insulation should possess not only good ablation resistance but also good interface and thermal insulation properties. Good mechanical properties can effectively resist mechanical erosion in harsh environments and enable the composite material to bear a certain load. Good thermal insulation properties can effectively block heat transfer inward, extending the service life of thermal protection materials and protecting the flight safety of the aircraft. Therefore, the development of carbon fiber / phenolic resin composites that can simultaneously possess excellent interfacial properties, ablation resistance, and thermal insulation to meet their requirements as integrated thermal protection composites in the aerospace or military fields has become a research hotspot in the field of ablation-resistant carbon fiber / phenolic resin composites. Summary of the Invention

[0004] To address the aforementioned technical problems, embodiments of the present invention provide a method for preparing carbon fiber / phenolic resin composite materials.

[0005] To achieve the above objectives, the embodiments of the present invention adopt the following technical solutions:

[0006] This invention provides a method for preparing carbon fiber / phenolic resin composite material, comprising the following steps:

[0007] A. Desizing the carbon fiber in an organic solvent;

[0008] B. The carbon fibers after desizing in step A are immersed in an immersion solution containing tannic acid, octaaminocage polysilsesquioxane and attapulgite, and then dried to obtain modified carbon fibers.

[0009] C. Dissolve phenolic resin in an organic solvent to prepare an impregnation solution, and coat it onto the modified carbon fiber from step B. After drying, a prepreg is obtained. The prepregs are stacked in sequence and then hot-pressed and cured to obtain a modified carbon fiber / phenolic resin composite material.

[0010] In some embodiments, in step A, the desizing process specifically involves heating the carbon fiber in acetone to remove the sizing agent from the surface of the carbon fiber, then washing away excess acetone with deionized water and vacuum drying.

[0011] In some embodiments, in step A, the mass ratio of the carbon fiber to the phenolic resin in step C is 1:1.

[0012] In some embodiments, in step B, the concentration of tannic acid is 0.5-4.0 g / L, the concentration of octaaminocage-like polysilsesquioxane is 0.5-4.0 g / L, and the concentration of attapulgite is 0.5 g / L.

[0013] In some embodiments, in step C, the phenolic resin includes at least one of magnesium phenolic resin, barium phenolic resin, and boron phenolic resin.

[0014] In some embodiments, in step C, the organic solvent includes at least one of ethanol, propanol, and acetone.

[0015] In some embodiments, in step C, the mass ratio of the organic solvent to the phenolic resin is 1:2-4:1.

[0016] In some embodiments, in step C, the hot pressing and curing process is divided into three stages: the first stage temperature is 100-120℃, the heating rate is 2℃ / min, and the holding time is 30-60min; the second stage temperature is 140-160℃, the heating rate is 2℃ / min, and the holding time is 60-120min; the third stage temperature is 180-220℃, the heating rate is 2℃ / min, and the holding time is 60-180min.

[0017] This invention achieves simultaneous improvement in the interfacial properties, ablation resistance, and thermal insulation of carbon fiber / phenolic resin composites by constructing a synergistic reinforcing mortar structure on the surface of carbon fibers to prepare an integrated load-bearing, thermally insulating, and ablation-resistant composite material. This method also simplifies the process and reduces costs. Tannic acid and octaaminocage-like polysilsesquioxane can undergo Michael addition and Schiff base reactions in an alkaline environment to generate an adhesive polymer. Simultaneously, tannic acid can chemically react with attapulgite. Therefore, tannic acid, octaaminocage-like polysilsesquioxane, and attapulgite can form a mortar structure on the carbon fiber surface under alkaline conditions, with tannic acid and octaaminocage-like polysilsesquioxane as the "slurry" and attapulgite as the "bricks." The construction of the mortar structure improves the fiber interface roughness and surface energy, and enhances the mechanical interlocking between the carbon fiber and phenolic resin matrix through multi-scale interfaces, significantly improving the interfacial properties of the carbon fiber / phenolic resin composite. Furthermore, the multi-scale porous structure of the mortar structure endows the carbon fiber / phenolic resin composite with excellent thermal insulation properties. In addition, the metal oxides and ceramics that can be generated from octaaminocage-like polysilsesquioxane and attapulgite at high temperatures effectively improve the high-temperature oxidation resistance and ablation resistance of carbon fiber / phenolic resin composites.

[0018] Furthermore, the preparation process of this invention is simple, the preparation time is short, the production cost is low, and it is easy to achieve mass production. This invention does not involve strong oxidants or strong acids in the modification of carbon fibers, making it green and environmentally friendly and without damaging the carbon fibers. The brick-mortar structure constructed by this invention further improves the interface roughness and high temperature resistance. The composite material prepared by this invention also has good interfacial properties, ablation resistance, and thermal insulation properties, and has broad application prospects in the fields of aerospace and military thermal protection. Attached Figure Description

[0019] Figure 1 The images show SEM images of the modified carbon fibers from Examples 1-5, Comparative Examples 2 and 3, where (a) is the SEM image of the modified carbon fiber from Example 5, (b) is the SEM image of the modified carbon fiber from Example 1, (c) is the SEM image of the modified carbon fiber from Example 2, (d) is the SEM image of the modified carbon fiber from Example 3, (e) is the SEM image of the modified carbon fiber from Example 4, (f) is the SEM image of the modified carbon fiber from Comparative Example 2, and (g) is the SEM image of the modified carbon fiber from Comparative Example 3.

[0020] Figure 2 SEM images of interface failure of samples from Comparative Example 2, Comparative Example 3 and Example 6 are shown, where (a) is an SEM image of interface failure of sample from Comparative Example 2, (b) is an SEM image of interface failure of sample from Comparative Example 3, and (c) is an SEM image of interface failure of sample from Example 6.

[0021] Figure 3The images show the surface morphology of the modified carbon fiber / phenolic resin composite material samples after ablation. (a) and (d) are the surface morphology of the modified carbon fiber / phenolic resin composite material sample of Comparative Example 2 after ablation, (b) and (e) are the surface morphology of the modified carbon fiber / phenolic resin composite material sample of Comparative Example 3 after ablation, and (c) and (f) are the surface morphology of the modified carbon fiber / phenolic resin composite material sample of Example 6 after ablation.

[0022] Figure 4 SEM images of the modified carbon fiber / phenolic resin composite sample prepared in Comparative Example 2 after ablation;

[0023] Figure 5 SEM images of the modified carbon fiber / phenolic resin composite sample prepared in Comparative Example 3 after ablation;

[0024] Figure 6 This is a SEM image of the modified carbon fiber / phenolic resin composite material sample obtained in Example 6 after ablation.

[0025] Figure 7 EDS image of the modified carbon fiber / phenolic resin composite sample after ablation, as shown in Comparative Example 2;

[0026] Figure 8 EDS images of the modified carbon fiber / phenolic resin composite sample after ablation, as shown in Comparative Example 3;

[0027] Figure 9 The image shows the EDS image of the modified carbon fiber / phenolic resin composite sample obtained in Example 6 after ablation. Detailed Implementation

[0028] The technical solutions in some embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments provided in this disclosure are within the scope of protection of this disclosure.

[0029] Example 1

[0030] Carbon fibers were soaked in acetone for 72 hours, and after washing away excess acetone with deionized water, they were dried in a vacuum oven at 80°C for 10 hours to obtain desized carbon fibers. The obtained desized carbon fibers were then immersed in a mixture containing 0.5 g / L tannic acid, 2 g / L octaaminocage-like polysilsesquioxane, and 0.5 g / L attapulgite for 4 hours, followed by drying at 80°C to obtain modified carbon fibers. Boron phenolic resin was poured into an equal mass of anhydrous ethanol and mechanically stirred at room temperature to obtain an impregnation solution. The impregnation solution was uniformly coated onto the carbon fiber fabric using a hand lay-up method (the mass ratio of carbon fiber to boron phenolic resin was 1:1), and then dried at room temperature to form a prepreg. The obtained carbon fiber prepregs were stacked and placed in a vulcanizing machine. The mixture was heated to 120℃ for 1 hour at a pressure of 5 MPa, with a heating rate of 2℃ / min, then heated to 150℃ and held for 1 hour, with a heating rate of 2℃ / min, then heated to 180℃ and held for 2 hours. Finally, the mixture was heated to 200℃ and held for 1 hour at a heating rate of 2℃ / min. After cooling and demolding with the press, the modified carbon fiber / phenolic resin composite material was obtained.

[0031] Example 2

[0032] Carbon fibers were soaked in acetone for 72 hours, and after washing away excess acetone with deionized water, they were dried in a vacuum oven at 80°C for 10 hours to obtain desized carbon fibers. The obtained desized carbon fibers were then immersed in a mixture containing 1 g / L tannic acid, 2 g / L octaaminocage-like polysilsesquioxane, and 0.5 g / L attapulgite for 4 hours, and dried at 80°C to obtain modified carbon fibers. Boron phenolic resin was poured into an equal mass of anhydrous ethanol and mechanically stirred at room temperature to obtain an impregnation solution. The impregnation solution was uniformly coated onto the carbon fiber fabric using a hand lay-up method (the mass ratio of carbon fiber to boron phenolic resin was 1:1), and then dried at room temperature to form a prepreg. The obtained carbon fiber prepregs were stacked and placed in a vulcanizing machine. The mixture was heated to 120℃ for 1 hour at a pressure of 5 MPa, with a heating rate of 2℃ / min, then heated to 150℃ and held for 1 hour, with a heating rate of 2℃ / min, then heated to 180℃ and held for 2 hours. Finally, the mixture was heated to 200℃ and held for 1 hour at a heating rate of 2℃ / min. After cooling and demolding with the press, the modified carbon fiber / phenolic resin composite material was obtained.

[0033] Example 3

[0034] Carbon fibers were soaked in acetone for 72 hours, and after washing away excess acetone with deionized water, they were dried in a vacuum oven at 80°C for 10 hours to obtain desized carbon fibers. The obtained desized carbon fibers were then immersed in a mixture containing 2 g / L tannic acid, 1 g / L octaaminocage-like polysilsesquioxane, and 0.5 g / L attapulgite for 4 hours, and dried at 80°C to obtain modified carbon fibers. Boron phenolic resin was poured into an equal mass of anhydrous ethanol and mechanically stirred at room temperature to obtain an impregnation solution. The impregnation solution was uniformly coated onto the carbon fiber fabric using a hand lay-up method (the mass ratio of carbon fiber to boron phenolic resin was 1:1), and then dried at room temperature to form a prepreg. The obtained carbon fiber prepregs were stacked and placed in a vulcanizing machine. The mixture was heated to 120℃ for 1 hour at a pressure of 5 MPa, with a heating rate of 2℃ / min, then heated to 150℃ and held for 1 hour, with a heating rate of 2℃ / min, then heated to 180℃ and held for 2 hours. Finally, the mixture was heated to 200℃ and held for 1 hour at a heating rate of 2℃ / min. After cooling and demolding with the press, the modified carbon fiber / phenolic resin composite material was obtained.

[0035] Example 4

[0036] Carbon fibers were soaked in acetone for 72 hours, and after washing away excess acetone with deionized water, they were dried in a vacuum oven at 80°C for 10 hours to obtain desized carbon fibers. The obtained desized carbon fibers were then immersed in a mixture containing 2 g / L tannic acid, 0.5 g / L octaaminocage-like polysilsesquioxane, and 0.5 g / L attapulgite for 4 hours, and dried at 80°C to obtain modified carbon fibers. Boron phenolic resin was poured into an equal mass of anhydrous ethanol and mechanically stirred at room temperature to obtain an impregnation solution. The impregnation solution was uniformly coated onto the carbon fiber fabric using a hand lay-up method (the mass ratio of carbon fiber to boron phenolic resin was 1:1), and then dried at room temperature to form a prepreg. The obtained carbon fiber prepregs were stacked and placed in a vulcanizing machine. The mixture was heated to 120℃ for 1 hour at a pressure of 5 MPa, with a heating rate of 2℃ / min, then heated to 150℃ and held for 1 hour, with a heating rate of 2℃ / min, then heated to 180℃ and held for 2 hours. Finally, the mixture was heated to 200℃ and held for 1 hour at a heating rate of 2℃ / min. After cooling and demolding with the press, the modified carbon fiber / phenolic resin composite material was obtained.

[0037] Example 5

[0038] Carbon fibers were soaked in acetone for 72 hours, and after washing away excess acetone with deionized water, they were dried in a vacuum oven at 80°C for 10 hours to obtain desized carbon fibers. The obtained desized carbon fibers were then immersed in a mixture containing 2 g / L tannic acid, 2 g / L octaaminocage-like polysilsesquioxane, and 0.5 g / L attapulgite for 4 hours, and dried at 80°C to obtain modified carbon fibers. Boron phenolic resin was poured into an equal mass of anhydrous ethanol and mechanically stirred at room temperature to obtain an impregnation solution. The impregnation solution was uniformly coated onto the carbon fiber fabric using a hand lay-up method (the mass ratio of carbon fiber to boron phenolic resin was 1:1), and then dried at room temperature to form a prepreg. The obtained carbon fiber prepregs were stacked and placed in a vulcanizing machine. The modified carbon fiber / phenolic resin composite material was obtained by heating at 120℃ for 1 hour under 5 MPa pressure at a rate of 2℃ / min, then heating to 150℃ for 1 hour at a rate of 2℃ / min, then heating to 180℃ for 2 hours, and finally heating to 200℃ for 1 hour at a rate of 2℃ / min. The material was then cooled and demolded using a press. The interlaminar shear strength of the obtained sample was 37.41 MPa at room temperature; the interlaminar shear strength after high-temperature oxidation was 2.41 MPa; the oxy-acetylene linear ablation rate was -0.0068 mm / s, the mass ablation rate was 0.035 g / s; and the thermal conductivity was 1.14 W / m·K.

[0039] Example 6

[0040] Carbon fibers were soaked in acetone for 72 hours, and after washing away excess acetone with deionized water, they were dried in a vacuum oven at 80°C for 10 hours to obtain desized carbon fibers. The obtained desized carbon fibers were then immersed in a mixture containing 2 g / L tannic acid, 2 g / L octaaminocage-like polysilsesquioxane, and 0.5 g / L attapulgite for 8 hours, followed by drying at 80°C to obtain modified carbon fibers. Boron phenolic resin was dissolved in an equal mass of anhydrous ethanol and mechanically stirred at room temperature to obtain an impregnation solution. The impregnation solution was evenly coated onto the carbon fiber fabric using a hand lay-up method, and the fibers were thoroughly impregnated with a brush. The fabric was then dried at room temperature to form a prepreg. The obtained carbon fiber prepregs were stacked and placed in a vulcanizing machine. The modified carbon fiber / phenolic resin composite material was obtained by heating at 120℃ for 1 hour under 5 MPa pressure at a rate of 2℃ / min, then heating to 150℃ for 1 hour at a rate of 2℃ / min, then heating to 180℃ for 2 hours, and finally heating to 200℃ for 1 hour at a rate of 2℃ / min. The material was then cooled and demolded using a press. The interlaminar shear strength of the obtained sample was 38.43 MPa at room temperature; the interlaminar shear strength after high-temperature oxidation was 2.65 MPa; the oxy-acetylene linear ablation rate was -0.013 mm / s, the mass ablation rate was 0.032 g / s; and the thermal conductivity was 1.04 W / m·K.

[0041] Example 7

[0042] Carbon fibers were soaked in acetone for 72 hours, and after washing away excess acetone with deionized water, they were dried in a vacuum oven at 80°C for 10 hours to obtain desized carbon fibers. The obtained desized carbon fibers were then immersed in a mixture containing 2 g / L tannic acid, 2 g / L octaaminocage-like polysilsesquioxane, and 0.5 g / L attapulgite for 12 hours, and dried at 80°C to obtain modified carbon fibers. Boron phenolic resin was poured into an equal mass of anhydrous ethanol and mechanically stirred at room temperature to obtain an impregnation solution. The impregnation solution was evenly coated onto the carbon fiber fabric using a hand lay-up method, and the fibers were thoroughly impregnated with a brush. The fabric was then dried at room temperature to form a prepreg. The obtained carbon fiber prepregs were stacked and placed in a vulcanizing machine. The modified carbon fiber / phenolic resin composite material was obtained by heating at 120℃ for 1 hour under 5 MPa pressure at a rate of 2℃ / min, then heating to 150℃ and holding for 1 hour at the same rate, then heating to 180℃ and holding for 2 hours, and finally heating to 200℃ and holding for 1 hour at a rate of 2℃ / min. The material was then cooled and demolded using the press. The interlaminar shear strength of the obtained sample was 37.11 MPa at room temperature; the interlaminar shear strength after high-temperature oxidation was 2.92 MPa; the oxy-acetylene linear ablation rate was 0.0075 mm / s, the mass ablation rate was 0.032 g / s; and the thermal conductivity was 1.08 W / m·K.

[0043] Comparative Example 1: Preparation of carbon fiber / phenolic resin composite materials

[0044] Boron phenolic resin was dissolved in an equal mass of anhydrous ethanol and mechanically stirred at room temperature to obtain an impregnation solution. The impregnation solution was uniformly coated onto carbon fibers using a hand lay-up method, and then dried at room temperature to form a prepreg. The obtained carbon fiber prepregs were stacked and placed in a vulcanizing machine. The mixture was heated to 120℃ for 1 hour at a rate of 2℃ / min under 5 MPa pressure, then to 150℃ for 1 hour at a rate of 2℃ / min, then to 180℃ for 2 hours, and finally to 200℃ for 1 hour at a rate of 2℃ / min. The mixture was then cooled and demolded under the pressure of the press to obtain the modified carbon fiber / phenolic resin composite material. The obtained sample showed an interlaminar shear strength of 31.01 MPa at room temperature; an interlaminar shear strength of 1.58 MPa after high-temperature oxidation; an oxy-acetylene linear ablation rate of 0.042 mm / s; a mass ablation rate of 0.038 g / s; and a thermal conductivity of 1.11 W / m·K.

[0045] Comparative Example 2: Preparation of Desizing Carbon Fiber / Phenolic Resin Composite Material

[0046] Carbon fibers were soaked in acetone for 72 hours, and after washing away excess acetone with deionized water, they were dried in a vacuum oven at 80°C for 10 hours to obtain modified carbon fibers. Boron phenolic resin was poured into an equal mass of anhydrous ethanol and mechanically stirred at room temperature to obtain an impregnation solution. The impregnation solution was uniformly coated onto the modified carbon fibers using a hand lay-up method, and then dried at room temperature to form a prepreg. The obtained carbon fiber prepregs were stacked and placed in a vulcanizing machine. The mixture was heated to 120°C for 1 hour at a pressure of 5 MPa, with a heating rate of 2°C / min, then heated to 150°C for 1 hour, with a heating rate of 2°C / min, then heated to 180°C for 2 hours, and finally heated to 200°C for 1 hour at a heating rate of 2°C / min. The mixture was then cooled and demolded using the press to obtain the modified carbon fiber / phenolic resin composite material. The interlaminar shear strength of the obtained sample at room temperature was 28.09 MPa; the interlaminar shear strength after high-temperature oxidation was 2.48 MPa; the oxy-acetylene linear ablation rate was 0.0083 mm / s, the mass ablation rate was 0.038 g / s; and the thermal conductivity was 1.21 W / m·K.

[0047] Comparative Example 3: Preparation of Co-deposition Modified Carbon Fiber / Phenolic Resin Composites

[0048] Carbon fibers were soaked in acetone for 72 hours, and after washing away excess acetone with deionized water, they were dried in a vacuum oven at 80°C for 10 hours to obtain desized carbon fiber cloth. The obtained desized carbon fibers were then immersed in a mixture containing 2 g / L tannic acid and 2 g / L octaaminocage-like polysilsesquioxane for 12 hours, and dried at 80°C to obtain co-deposited modified carbon fibers. Boron phenolic resin was added to an equal mass of anhydrous ethanol and mechanically stirred at room temperature to obtain an impregnation solution. The impregnation solution was evenly coated onto the modified carbon fibers using a hand lay-up method, and the fibers were thoroughly impregnated with a brush. The fibers were then dried at room temperature to form a prepreg. The obtained carbon fiber prepregs were stacked and placed in a vulcanizing machine. The carbon fiber / phenolic resin composite material was obtained by heating at 120℃ for 1 hour under 5 MPa pressure at a rate of 2℃ / min, then heating to 150℃ for 1 hour at a rate of 2℃ / min, then heating to 180℃ for 2 hours, and finally heating to 200℃ for 1 hour at a rate of 2℃ / min. After cooling and demolding, the co-deposited modified carbon fiber / phenolic resin composite material was obtained. The interlaminar shear strength of the obtained sample at room temperature was 36.51 MPa; the flexural strength and interlaminar shear strength after high-temperature oxidation were 2.46 MPa; the oxy-acetylene linear ablation rate was 0.0078 mm / s, the mass ablation rate was 0.038 g / s; and the thermal conductivity was 1.08 W / m·K.

[0049] A comparison of the examples and comparative examples shows that, compared to carbon fiber / phenolic resin and co-deposition modified carbon fiber composites, the mortar structure significantly improves the ablation resistance, interfacial properties, and thermal insulation of the composites. The mortar structure modification enhances the fiber interface roughness and surface energy, and strengthens the mechanical interlocking between the carbon fiber and phenolic resin matrix through multi-scale interfaces, thereby improving the mechanical properties of the composites. Simultaneously, the multi-scale porous structure of the mortar structure endows the carbon fiber composites with excellent thermal insulation properties. Furthermore, octaaminocage-like polysilsesquioxane and attapulgite can generate metal oxides and ceramics at high temperatures, effectively improving the high-temperature oxidation resistance and ablation resistance of the carbon fibers.

[0050] While co-deposition structures can effectively improve the interfacial properties of composite materials, the presence of a large amount of organic matter promotes the thermal decomposition of the phenolic resin matrix during ablation, resulting in poor ablation performance of the composite material. Mortar structures, on the one hand, introduce inorganic materials to improve the high-temperature resistance of the interface, and on the other hand, the construction of a multi-scale porous structure further enhances the thermal insulation of the composite material. Figure 1 This confirms the successful construction of the brick-mortar structure on the carbon fiber surface; Figure 2 This indicates that the construction of a brick-mortar structure can effectively improve the interfacial bonding strength of carbon fiber composite materials; Figure 3 The composite material prepared in Example 6 exhibits a more complete microstructure of carbon fibers after ablation and contains adhesive substances. This further demonstrates that the construction of the mortar structure can effectively improve the high-temperature oxidation resistance of carbon fibers, thereby enhancing the ablation resistance of the composite material. Figures 4-6 The figures show the central morphology of samples from Comparative Examples 2, 3, and 6 after ablation. It can be observed from the figures that the fiber morphology was severely damaged after ablation. A ceramic protective phase can be observed on the carbon fibers after co-deposition modification and mortar structure modification. Figures 7-9 The corresponding EDS spectra further confirmed the presence of the ceramic protective phase. Combined with the ablation performance of Comparative Examples 2, 3, and 6, it is further demonstrated that the formation of inorganic matter on the carbon fiber surface effectively improves the ablation performance of the carbon fiber. Furthermore, due to the superior interfacial properties of the mortar structure, the composite material of Example 6 contains more resin matrix, thereby better protecting the carbon fiber from oxidation and improving the ablation performance of the composite material.

[0051] In the description of this specification, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0052] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for preparing a carbon fiber / phenolic resin composite material, characterized in that, Includes the following steps: A. The carbon fiber is placed in an organic solvent for desizing treatment; the desizing treatment specifically involves heating the carbon fiber in acetone to remove the sizing agent on the surface of the carbon fiber, then washing away excess acetone with deionized water and vacuum drying. B. The carbon fibers after desizing in step A are immersed in an immersion solution containing tannic acid, octaaminocage-like polysilsesquioxane, and attapulgite, and then dried to obtain modified carbon fibers; wherein the concentration of tannic acid is 0.5-4.0 g / L, the concentration of octaaminocage-like polysilsesquioxane is 0.5-4.0 g / L, and the concentration of attapulgite is 0.5 g / L. C. Dissolve phenolic resin in an organic solvent to prepare an impregnation solution, and coat it onto the modified carbon fiber from step B. After drying, a prepreg is obtained. The prepregs are stacked in sequence and then hot-pressed and cured to obtain a modified carbon fiber / phenolic resin composite material.

2. The preparation method according to claim 1, characterized in that, In step A, the mass ratio of the carbon fiber to the phenolic resin in step C is 1:

1.

3. The preparation method according to claim 1, characterized in that, In step C, the phenolic resin includes at least one of magnesium phenolic resin, barium phenolic resin, and boron phenolic resin.

4. The preparation method according to claim 1, characterized in that, In step C, the organic solvent includes at least one of ethanol, propanol, and acetone.

5. The preparation method according to claim 1, characterized in that, In step C, the mass ratio of the organic solvent to the phenolic resin is 1:2-4:

1.

6. The preparation method according to claim 1, characterized in that, In step C, the hot pressing and curing process is divided into three stages: the first stage temperature is 100-120 ℃, the heating rate is 2 ℃ / min, and the holding time is 30-60 min; the second stage temperature is 140-160 ℃, the heating rate is 2 ℃ / min, and the holding time is 60-120 min; the third stage temperature is 180-220 ℃, the heating rate is 2 ℃ / min, and the holding time is 60-180 min.

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