Preparation method of novel epoxy resin composite material

Abstract

The invention relates to the technical field of preparation of new materials, and discloses a preparation method of a novel epoxy resin composite material, which comprises the following steps: adding 1.5-2.5 g of gallic acid and 1.5-2.5 g of polyethyleneimine into 0.8-1.2 L of deionized water, and stirring at 25-30 DEG C for 20-30 minutes until the gallic acid and the polyethyleneimine are completely dissolved to obtain a gallic acid and polyethyleneimine mixed solution; and washing the non-sized carbon fibers, drying the non-sized carbon fibers in a drying oven, and then completely dipping the dried carbon fibers in the gallic acid and polyethyleneimine mixed solution. The carbon fibers are preliminarily modified by gallic acid and polyethyleneimine, so that the chemical activity and hydrophilicity of the surfaces of the carbon fibers can be effectively improved, in-situ growth of Mg (OH) 2 on the surfaces of the carbon fibers is realized by combining step-by-step treatment of a magnesium source solution and an alkaline solution, and a formed Mg (OH) 2 / gallic acid / polyethyleneimine synergistic modification system is used for improving the mechanical properties of the carbon fibers. A good modification effect is achieved on an interface, and the mechanical property of the composite material is improved.

Description

Technical Field

[0001] This invention relates to the field of new material preparation technology, specifically to a method for preparing a novel epoxy resin composite material. Background Technology

[0002] Carbon fiber reinforced epoxy resin composites (carbon fiber / epoxy resin composites) have become a core choice for high-end structural materials due to the advantages of carbon fiber's high strength, high modulus and low density. They can effectively meet the dual requirements of various load-bearing components for material mechanical properties and weight reduction.

[0003] In the performance system of carbon fiber / epoxy resin composites, the interfacial bonding strength between carbon fiber and epoxy resin matrix is ​​a key factor determining the overall mechanical properties of the material. The interfacial bonding effect directly affects the stress transfer efficiency between the reinforcement and the matrix. If the interfacial bonding is not tight, stress concentration, interfacial debonding, or even delamination can easily occur during the stress process, leading to a significant decrease in the core mechanical properties of the composite material, such as flexural strength and impact strength, making it difficult to meet the structural load-bearing requirements of practical applications. However, unmodified carbon fiber surfaces have a high degree of graphitization, strong chemical inertness, and lack active groups that can chemically bond or strongly interact with the epoxy resin matrix. They also have poor hydrophilicity, resulting in inherently insufficient interfacial compatibility with the epoxy resin matrix and low interfacial bonding strength. This problem has become a core bottleneck restricting the performance improvement of carbon fiber / epoxy resin composites.

[0004] To improve interfacial properties, chemical modification is the mainstream approach. Inspired by the adhesive properties of mussel adhesive proteins, polydopamine is widely used as a biomimetic modifying material. It can form a coating on the surface of carbon fibers and interact with epoxy resin through active groups. However, polydopamine monomers are expensive and have long polymerization cycles, making it difficult to achieve large-scale industrial production. There is an urgent need to develop low-cost and efficient alternatives.

[0005] Existing research indicates that co-deposition of polyphenolic compounds containing catechol or pyrogallol structures with polyamine compounds can form polydopamine-like phenol-amine polymer coatings. Based on this, this invention proposes an innovative multi-scale modification approach: gallic acid (GA), extracted from natural plants, is selected as the polyphenolic compound. Containing a pyrogallol structure, it is not only significantly cheaper than dopamine but also exhibits higher reactivity. Combined with the amino-rich, water-soluble polymer polyethyleneimine (PEI), the two can be mildly co-deposited under alkaline conditions through Michael addition and Schiff base reactions to form a phenol-amine polymer coating with both strong adhesion and excellent hydrophilicity. This coating solves the cost and scalability challenges of polydopamine, and its good hydrophilicity provides a suitable substrate for subsequent inorganic phase growth. Furthermore, rigid Mg(OH)₂ is introduced into the coating surface through in-situ growth, constructing an organic (GA-PEI coating)-inorganic (Mg(OH)₂) three-dimensional interface layer, achieving multi-scale synergistic modification.

[0006] This multi-scale modification system enhances the surface activity of carbon fibers and reacts efficiently with the epoxy functional groups of epoxy resin through multiple interactions such as covalent bonds, hydrogen bonds, and coordination bonds. It overcomes the limitations of traditional single modification (such as low grafting density of silane coupling agents and poor dispersion of nanoparticles) in terms of interfacial reinforcement, ultimately achieving a significant improvement in the mechanical properties of composite materials. This provides a new path for the high-performance and large-scale application of carbon fiber / epoxy resin composite materials. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a novel method for preparing epoxy resin composite materials, which solves the problems mentioned in the background section.

[0008] To achieve the above objectives, the present invention provides the following technical solution: a method for preparing a novel epoxy resin composite material, comprising the following steps:

[0009] S1. Add 1.5–2.5 g gallic acid and 1.5–2.5 g polyethyleneimine to 0.8–1.2 L of deionized water and stir at 25–30 °C for 20–30 min until completely dissolved to obtain a mixed solution of gallic acid and polyethyleneimine. Wash the unsized carbon fiber filaments and dry them in an oven. Then, completely immerse the dried carbon fiber filaments in the above mixed solution of gallic acid and polyethyleneimine. Add 2.0 ± 0.2 g / L Tris-HCl buffer solution to the mixed solution to adjust the pH to 8.5. Keep it standing at room temperature for 3.5–4.5 hours. After the reaction is complete, wash the obtained carbon fiber three times with deionized water and finally dry it in an oven to obtain gallic acid and polyethyleneimine modified carbon fiber.

[0010] S2. The obtained gallic acid and polyethyleneimine modified carbon fibers are completely impregnated in a solution providing magnesium source. After impregnation, they are placed in an oven to dry. After drying, the carbon fibers are completely impregnated in an alkaline solution. After impregnation in the alkaline solution, the carbon fibers are washed with deionized water to remove the alkaline solution residue on the surface. Then, the washed carbon fibers are placed in an oven to dry, obtaining Mg(OH)2 / gallic acid / polyethyleneimine synergistic modified carbon fiber tow.

[0011] S3. Weigh epoxy resin, curing agent, and accelerator according to the proportions, mix them thoroughly, and then remove air bubbles from the mixture using a vacuum degassing method to obtain a resin matrix adhesive. Set the temperature of the constant temperature digital display heating stage to 40-50℃, and at this temperature, uniformly coat the resin matrix adhesive onto the surface of the Mg(OH)2 / gallic acid / polyethyleneimine synergistic modified carbon fiber tow obtained in S2. Then, place the coated carbon fiber tow into a vacuum drying oven and immerse it at 53-57℃ for 30-45 minutes to obtain modified carbon fiber prepreg. The material is placed in a metal mold, and the molding pressure of the infrared tablet press is set to 14-16 MPa. The pressure is maintained for 28-32 minutes. After the pressure is maintained, the metal mold is fixed with a heavy-duty G-clamp. Then the mold is placed in an environment of 88-92℃ for 0.8-1.2 hours, 128-132℃ for 1.8-2.2 hours, and 148-152℃ for 2-3 hours for curing. After curing, the material is cooled to room temperature and the product is removed to obtain a Mg(OH)2 / gallic acid / polyethyleneimine synergistic modified carbon fiber / epoxy resin composite material.

[0012] Preferably, the specific operation of washing the unsized carbon fiber filaments in S1 is as follows: the unsized carbon fiber filaments are placed in deionized water and ultrasonically washed 2 to 3 times with an ultrasonic cleaner at a power of 280 to 420W, with each ultrasonic washing time being 12 to 22 minutes.

[0013] Preferably, the magnesium source solution in S2 is a magnesium chloride solution with a concentration of 0.1 to 0.2 mol / L.

[0014] Preferably, the alkaline solution in S2 is a sodium hydroxide solution with a concentration of 0.1-0.2 mol / L. The operating conditions for completely immersing the carbon fiber in the alkaline solution in S2 are: immersion temperature 18-62℃, immersion time 4-16 min, so that the alkaline solution acts uniformly on the surface of the carbon fiber.

[0015] Preferably, the specific conditions for drying the washed carbon fiber in the oven in step S2 are as follows: a vacuum oven is used for drying, the vacuum degree in the vacuum oven is controlled at -0.09 to -0.08 MPa, the drying temperature is set at 58-82℃, the drying time is 5.5 to 8.5 hours, and the carbon fiber is weighed after drying to ensure that its moisture content is less than 0.6%.

[0016] Preferably, the specific ratio of epoxy resin, curing agent and accelerator weighed in step S3 is as follows: the mass ratio of epoxy resin, methyltetrahydrophthalic anhydride curing agent and 2,4,6-tris(dimethylaminomethyl)phenol accelerator is 1000:700:2.

[0017] Preferably, in the process of preparing modified carbon fiber prepreg in S3, 3 to 5 parallel samples are prepared for each group of experiments, and the size of each parallel sample is 78 to 82 mm × 10 to 14 mm × 1.8 to 2.2 mm. After preparation, the bending performance of the parallel samples is tested using a universal testing machine. The test conditions are: the span is set to 28 to 32 mm, the loading rate is 0.8 to 1.2 mm / min, the test environment temperature is 23 to 27℃, and the relative humidity is 48% to 62%. The average value of the bending strength test results of all parallel samples is taken as the bending strength data of the experimental product of that group.

[0018] This invention provides a novel method for preparing epoxy resin composite materials. It has the following beneficial effects:

[0019] 1. This invention uses gallic acid and polyethyleneimine to initially modify carbon fibers, which can effectively improve the chemical activity and hydrophilicity of the carbon fiber surface. Combined with stepwise treatment of magnesium source solution and alkaline solution, Mg(OH)2 is grown in situ on the carbon fiber surface, forming a synergistic modification system of Mg(OH)2 / gallic acid / polyethyleneimine. This synergistic effect can significantly enhance the interfacial bonding strength between carbon fibers and epoxy resin matrix, avoiding the performance shortcomings caused by the traditional loose bonding between carbon fibers and resin matrix, thereby improving the overall mechanical properties of the final composite material, ensuring more uniform stress transmission during the stress process, and possessing better structural stability.

[0020] 2. The process design of this preparation method has good scientific validity and operability. All reagents used are conventional chemical raw materials, which are easy to obtain and environmentally friendly, and there are no special harsh reaction conditions. During the preparation process, the pH value is precisely controlled by Tris-HCl buffer, the water content is controlled by vacuum drying, and the degree of resin crosslinking is controlled by stepwise curing. These detailed designs can effectively ensure the stability and repeatability of the modification effect. At the same time, the parallel sample preparation and standardized performance testing process can further ensure the controllability of product quality, avoid performance differences caused by process fluctuations, facilitate industrial mass production, and provide reliable process support for the practical application of novel epoxy resin composite materials. Attached Figure Description

[0021] Figure 1 This is the overall flowchart of the present invention;

[0022] Figure 2 This is a comparison diagram of the flexural strength of the composite material under different preparation methods of the present invention;

[0023] Figure 3 SEM images of the surface morphology of the composite material under different preparation methods of the present invention. Detailed Implementation

[0024] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] Please see the appendix Figure 1 -Appendix Figure 3 This invention provides a method for preparing a novel epoxy resin composite material.

[0026] Comparative Example 1: Preparation of Gallic Acid / Polyethyleneimine Modified Carbon Fiber / Epoxy Resin Composite Material

[0027] This comparative example is used to compare and verify the effect of Mg(OH)2 synergistic modification on the properties of epoxy resin composites. The specific preparation steps are as follows:

[0028] Preparation of S1 gallic acid / polyethyleneimine modified carbon fiber

[0029] Weigh 2.0 g gallic acid and 2.0 g polyethyleneimine, add them to 1.0 L of deionized water, and stir at 250 r / min for 25 min at 28 °C until completely dissolved to obtain a mixed solution of gallic acid and polyethyleneimine. Take unsized carbon fiber filaments, put them into deionized water, and ultrasonically wash them twice at 300 W power using an ultrasonic cleaner, each ultrasonic washing time being 15 min. After washing, place the carbon fiber filaments in a 60 °C oven to dry for 3.0 h. Then, completely immerse the dried carbon fiber filaments in the above mixed solution, add 2.0 g / L Tris-HCl buffer solution to the solution to adjust the pH value to 8.5, and keep it standing at room temperature (25 °C) for 4.0 h. After the reaction is completed, wash the obtained carbon fiber three times with deionized water, and finally place it in a 60 °C oven to dry for 3.0 h to obtain gallic acid and polyethyleneimine modified carbon fiber.

[0030] S2. Preparation of gallic acid / polyethyleneimine modified carbon fiber / epoxy resin composite material

[0031] Epoxy resin, curing agent, and accelerator were weighed at a mass ratio of 1000:700:2. The mixture was stirred at 250 r / min for 20 min while maintaining an ambient temperature of 28°C. Then, a vacuum degassing machine was used to remove air bubbles from the mixture at a vacuum of -0.095 MPa and a temperature of 28°C for 10 min to obtain a resin matrix filament. The temperature of the constant temperature digital display heating stage was set to 45°C. At this temperature, the resin matrix filament was uniformly coated onto the surface of the modified carbon fiber tow obtained in S1 using a scraper. The coated carbon fiber tow was then placed in a vacuum drying oven and impregnated at 55°C for 35 min to obtain the modified carbon fiber prepreg.

[0032] The prepreg was placed in a metal mold, and the molding pressure was set to 15 MPa on an infrared tablet press. The pressure was maintained for 30 minutes. After the pressure was maintained, the metal mold was fixed with a heavy-duty G-clamp. The mold was then placed in an environment of 90°C for 1.0 h, 130°C for 2.0 h, and 150°C for 2.5 h for curing. After curing, the mold was cooled to room temperature, and the product was removed to obtain gallic acid / polyethyleneimine modified carbon fiber / epoxy resin composite material.

[0033] Five parallel samples were prepared for each group. The bending performance of the parallel samples was tested using a universal testing machine. The test conditions were: span set at 30 mm, loading rate at 1 mm / min, ambient temperature at 25 ℃, and relative humidity at 50%. The average value of the bending strength test results of the five parallel samples was taken as the final performance data. The average bending strength of the composite material was measured to be 669.9 MPa.

[0034] Example 1: Preparation of Mg(OH)₂-modified epoxy resin composite material in alkaline solution at 20℃

[0035] This embodiment uses a 20℃ alkaline solution to achieve in-situ growth of Mg(OH)2 on the carbon fiber surface. The specific preparation steps are as follows:

[0036] Preparation of S1 gallic acid / polyethyleneimine modified carbon fiber

[0037] Completely consistent with Comparative Example S1: Weigh 2.0 g gallic acid and 2.0 g polyethyleneimine, add to 1.0 L deionized water, and stir at 28 °C for 25 min until completely dissolved; after the unsized carbon fiber filaments are ultrasonically washed twice at 300 W (15 min each time) and dried at 60 °C for 3.0 h, they are completely immersed in the mixed solution, the pH is adjusted to 8.5 with 2.0 g / L Tris-HCl buffer, and allowed to stand at room temperature for 4.0 h. After the reaction is completed, the obtained carbon fiber is washed three times with deionized water and finally dried at 60 °C for 3.0 h to obtain gallic acid and polyethyleneimine modified carbon fiber.

[0038] Preparation of S2, Mg(OH)2 / gallic acid / polyethyleneimine synergistic modified carbon fibers

[0039] A 1.0 mol / L magnesium chloride solution (magnesium source solution) was prepared, and the modified carbon fibers obtained in S1 were completely impregnated in the magnesium chloride solution at 20℃ for 5 min. During the impregnation process, the solution was gently stirred once every 2.5 min. After impregnation, the carbon fibers were placed in a vacuum oven and dried for 30 min at a vacuum degree of -0.085 MPa and a temperature of 60℃. Subsequently, a 0.1 mol / L sodium hydroxide solution (alkaline solution) was prepared, and the dried carbon fibers were completely impregnated in the sodium hydroxide solution at 20℃ for 5 min. After impregnation, the carbon fibers were repeatedly washed with deionized water until the washing solution was neutral. The washed carbon fibers were then placed in a vacuum oven and dried for 8.0 h at a vacuum degree of -0.085 MPa and a temperature of 60℃. After drying, the carbon fibers were weighed, and the water content was confirmed to be 0.4% (less than 0.6%), thus obtaining Mg(OH)2 / gallic acid / polyethyleneimine synergistic modified carbon fiber tow.

[0040] S3. Preparation of novel epoxy resin composite materials

[0041] Completely consistent with Comparative Example S2: The resin matrix solution was prepared at a mass ratio of 1000:700:2 and degassed under vacuum. It was coated on the surface of the modified carbon fiber tow obtained in S2 at 45°C and vacuum impregnated at 55°C for 35 min to obtain a prepreg. The prepreg was held under a pressure of 15 MPa for 30 min, and then cured in steps at 90°C / 1 h, 130°C / 2 h, and 150°C / 2.5 h. After cooling, a Mg(OH)2 / gallic acid / polyethyleneimine synergistic modified carbon fiber / epoxy resin composite material was obtained.

[0042] Five parallel samples were prepared for each group, and the bending performance was tested under the same test conditions as the control group. The average bending strength of the composite material was measured to be 741.8 MPa.

[0043] Example 2: Preparation of Mg(OH)₂-modified epoxy resin composite material in alkaline solution at 40℃

[0044] The only difference between this embodiment and Example 1 is that the immersion temperature of the sodium hydroxide solution (alkaline solution) in S2 is changed to 40°C. All other steps and parameters are completely consistent with Example 1, as follows:

[0045] Preparation of S1 gallic acid / polyethyleneimine modified carbon fiber

[0046] The steps and parameters are the same as in Example 1, and gallic acid and polyethyleneimine modified carbon fibers are obtained.

[0047] Preparation of S2, Mg(OH)2 / gallic acid / polyethyleneimine synergistic modified carbon fibers

[0048] The steps of impregnation in magnesium chloride solution (20℃, 5min) and vacuum drying (-0.085MPa, 60℃, 30min) are the same as in Example 1; the impregnation temperature in sodium hydroxide solution is adjusted to 40℃, and the impregnation time is still 5min. The subsequent washing and vacuum drying (-0.085MPa, 60℃, 8.0h) steps are the same as in Example 1, to obtain Mg(OH)2 / gallic acid / polyethyleneimine synergistic modified carbon fiber tow.

[0049] S3. Preparation of novel epoxy resin composite materials

[0050] The steps and parameters are the same as in Example 1, and the Mg(OH)2 / gallic acid / polyethyleneimine synergistic modified carbon fiber / epoxy resin composite material is obtained.

[0051] Five parallel samples were prepared for each group, and the bending performance was tested under the same test conditions. The average bending strength of the composite material was measured to be 818.3 MPa.

[0052] Example 3: Preparation of Mg(OH)₂-modified epoxy resin composite material in alkaline solution at 60℃

[0053] The only difference between this embodiment and Example 1 is that the immersion temperature of the sodium hydroxide solution (alkaline solution) in S2 is changed to 60°C. All other steps and parameters are completely consistent with Example 1, as follows:

[0054] Preparation of S1 gallic acid / polyethyleneimine modified carbon fiber

[0055] The steps and parameters are the same as in Example 1, and gallic acid and polyethyleneimine modified carbon fibers are obtained.

[0056] Preparation of S2, Mg(OH)2 / gallic acid / polyethyleneimine synergistic modified carbon fibers

[0057] The steps of impregnation in magnesium chloride solution (20℃, 5min) and vacuum drying (-0.085MPa, 60℃, 30min) are the same as in Example 1; the impregnation temperature in sodium hydroxide solution is adjusted to 60℃, and the impregnation time is still 5min. The subsequent washing and vacuum drying (-0.085MPa, 60℃, 8.0h, water content 0.42%) steps are the same as in Example 1, to obtain Mg(OH)2 / gallic acid / polyethyleneimine synergistic modified carbon fiber tow.

[0058] S3. Preparation of novel epoxy resin composite materials

[0059] The steps and parameters are the same as in Example 1, and the Mg(OH)2 / gallic acid / polyethyleneimine synergistic modified carbon fiber / epoxy resin composite material is obtained.

[0060] Five parallel samples were prepared for each group, and the bending performance was tested under the same test conditions. The average bending strength of the composite material was measured to be 721.6 MPa.

[0061] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a novel epoxy resin composite material, characterized in that, Includes the following steps: S1. Add 1.5–2.5 g gallic acid and 1.5–2.5 g polyethyleneimine to 0.8–1.2 L of deionized water and stir at 25–30 °C for 20–30 min until completely dissolved to obtain a mixed solution of gallic acid and polyethyleneimine. Wash the unsized carbon fiber filaments and dry them in an oven. Then, completely immerse the dried carbon fiber filaments in the above mixed solution of gallic acid and polyethyleneimine. Add 2.0 ± 0.2 g / L Tris-HCl buffer solution to the mixed solution to adjust the pH value to 8.

5. Keep it standing at room temperature for 3.5–4.5 hours. Finally, dry the impregnated carbon fiber filaments in an oven to obtain gallic acid and polyethyleneimine modified carbon fiber. S2. The obtained gallic acid and polyethyleneimine modified carbon fibers are completely impregnated in a solution providing magnesium source. After impregnation, they are placed in an oven to dry. After drying, the carbon fibers are completely impregnated in an alkaline solution. After impregnation in the alkaline solution, the carbon fibers are washed with deionized water to remove the alkaline solution residue on the surface. Then, the washed carbon fibers are placed in an oven to dry, obtaining Mg(OH)2 / gallic acid / polyethyleneimine synergistic modified carbon fiber tow. S3. Weigh epoxy resin, curing agent, and accelerator according to the proportions, mix them thoroughly, and then remove air bubbles from the mixture using a vacuum degassing method to obtain a resin matrix adhesive. Set the temperature of the constant temperature digital display heating stage to 40-50℃, and at this temperature, uniformly coat the resin matrix adhesive onto the surface of the Mg(OH)2 / gallic acid / polyethyleneimine synergistic modified carbon fiber tow obtained in S2. Then, place the coated carbon fiber tow into a vacuum drying oven and immerse it at 53-57℃ for 30-45 minutes to obtain modified carbon fiber prepreg. The material is placed in a metal mold, and the molding pressure of the infrared tablet press is set to 14-16 MPa. The pressure is maintained for 28-32 minutes. After the pressure is maintained, the metal mold is fixed with a heavy-duty G-clamp. Then the mold is placed in an environment of 88-92℃ for 0.8-1.2 hours, 128-132℃ for 1.8-2.2 hours, and 148-152℃ for 2-3 hours for curing. After curing, the material is cooled to room temperature and the product is removed to obtain a Mg(OH)2 / gallic acid / polyethyleneimine synergistic modified carbon fiber / epoxy resin composite material.

2. The method for preparing a novel epoxy resin composite material according to claim 1, characterized in that, The specific operation of washing the unsized carbon fiber filaments in S1 is as follows: the unsized carbon fiber filaments are placed in deionized water and ultrasonically washed 2 to 3 times with an ultrasonic cleaner at a power of 280 to 420W, with each ultrasonic washing time being 12 to 22 minutes.

3. The method for preparing a novel epoxy resin composite material according to claim 1, characterized in that, The magnesium source solution provided in S2 is a magnesium chloride solution with a concentration of 0.1–0.2 mol / L.

4. The method for preparing a novel epoxy resin composite material according to claim 1, characterized in that, The specific conditions for drying the sample after impregnation in step S2 are as follows: a vacuum oven is used for drying, the vacuum degree inside the vacuum oven is controlled between -0.09 and -0.08 MPa, the drying temperature is set to 58-72℃, the drying time is 28-62 min, and the vacuum degree is recorded every 12-18 min during the drying process to ensure that the vacuum degree is stable within the set range.

5. The method for preparing a novel epoxy resin composite material according to claim 1, characterized in that, The alkaline solution in S2 is a sodium hydroxide solution with a concentration of 0.1–0.2 mol / L. The operating conditions for completely immersing the carbon fiber in the alkaline solution in S2 are: immersion temperature 18–62°C, immersion time 4–16 min, so that the alkaline solution acts uniformly on the surface of the carbon fiber.

6. The method for preparing a novel epoxy resin composite material according to claim 1, characterized in that, The specific conditions for drying the washed carbon fiber in the oven in step S2 are as follows: a vacuum oven is used for drying, the vacuum degree in the vacuum oven is controlled at -0.09 to -0.08 MPa, the drying temperature is set at 58-82℃, the drying time is 5.5 to 8.5 hours, and the carbon fiber is weighed after drying to ensure that its moisture content is less than 0.6%.

7. The method for preparing a novel epoxy resin composite material according to claim 1, characterized in that, The specific ratio of epoxy resin, curing agent, and accelerator weighed in S3 is as follows: the mass ratio of epoxy resin, methyltetrahydrophthalic anhydride curing agent, and 2,4,6-tris(dimethylaminomethyl)phenol accelerator is 1000:700:

2.

8. The method for preparing a novel epoxy resin composite material according to claim 1, characterized in that, In the process of preparing modified carbon fiber prepreg in S3, 3 to 5 parallel samples were prepared for each group of experiments. The size of each parallel sample was 78 to 82 mm × 10 to 14 mm × 1.8 to 2.2 mm. After preparation, the bending performance of the parallel samples was tested using a universal testing machine. The test conditions were: span set at 28 to 32 mm, loading rate at 0.8 to 1.2 mm / min, ambient temperature at 23 to 27℃, and relative humidity at 48% to 62%. The average value of the bending strength test results of all parallel samples was taken as the bending strength data of the experimental product of that group.

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