High-temperature-resistant carbon fiber composite material

Abstract

The invention discloses a high-temperature-resistant carbon fiber composite material, and belongs to the field of polymer composite materials. The preparation method is used for solving the problems that in the prior art, carbon fibers and epoxy resin materials are poor in dispersion in compounding, bonding between interfaces of the carbon fibers and resin is poor, and heat resistance and mechanical properties need to be further improved, and comprises the steps that epoxy resin, functional filler and a catalyst are mixed, stirred and heated for reaction, and an intermediate I is obtained after the reaction is finished; mixing the intermediate I, a curing agent and an antioxidant, heating in a water bath, carrying out ultrasonic oscillation, uniformly stirring, and curing to obtain the high-temperature-resistant carbon fiber composite material. The high-temperature-resistant carbon fiber composite material prepared by the invention has good mechanical properties, heat resistance and flame retardance.

Description

Technical Field

[0001] The present invention relates to the field of polymer composites, and particularly to a high-temperature resistant carbon fiber composite material. Background Art

[0002] Carbon fiber is a microcrystalline graphite material obtained through carbonization and graphitization processes, having certain high-temperature resistance, friction resistance, and thermal conductivity. Traditional carbon fibers can be added as reinforcing materials to materials such as resins, metals, and ceramics to form composite materials, endowing new properties and expanding the scope of application. Carbon fiber-reinforced composite materials can be used as substitute materials such as aircraft structural materials, electromagnetic shielding and electricity removal materials, and for manufacturing rocket shells, motorboats, industrial robots, drive shafts, etc. Among them, the composite material of carbon fiber and epoxy resin has become an advanced aerospace material due to its low specific gravity, good rigidity, and high strength. However, the composite effect of carbon fiber and epoxy resin materials is not very ideal, and the bonding between the interface of carbon fiber and resin is relatively poor, with inferior heat resistance and mechanical properties, which limits its application.

[0003] Chinese Patent CN108424620A discloses a high-temperature resistant carbon fiber composite material and its preparation method. The specific preparation is as follows: carbon fiber, phenolic epoxy resin, ethylene-tetrafluoroethylene copolymer, glycidyl methacrylate, filler, curing agent, accelerator, antioxidant, and anti-aging agent are placed in a mixer for mixing, and then melt-extruded through a twin-screw extruder and extrusion molded to obtain a high-temperature resistant carbon fiber composite material; the high-temperature resistant carbon fiber composite material prepared by this invention has certain high-temperature resistance, but there is a problem of poor compatibility; Chinese Patent CN113105717B discloses a high-temperature resistant carbon fiber composite material and its preparation method, including the following steps: preparing a chitosan complex with 4-nitrophthalimide, urea, copper chloride, and chitosan; reacting carbon fiber with the chitosan complex and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide to obtain a mixture; blending the mixture with epoxy resin to obtain a high-temperature resistant carbon fiber composite material; the mechanical properties of the prepared high-temperature resistant carbon fiber composite material need to be further improved. Summary of the Invention

[0004] In order to solve the above technical problems, the present invention provides a high-temperature resistant carbon fiber composite material, which solves the problems of poor dispersion in the composite of carbon fiber and epoxy resin material in the prior art, relatively poor bonding between the interface of carbon fiber and resin, and the need for further improvement in heat resistance and mechanical properties.

[0005] In order to achieve the above object, the present invention provides a preparation method of a high-temperature resistant carbon fiber composite material, including the following steps: Step (1): Under a nitrogen atmosphere, add reduced carbon fiber and an amino-silane coupling agent to toluene, heat for reaction and keep warm, continue heating for reflux reaction, cool, wash, filter, and dry to obtain amino-modified carbon fiber; Step (2): Add phenyl dichlorophosphate and triethylamine to toluene, stir, add amino-modified carbon fiber, heat and react. After the reaction ends, filter, wash, and dry to obtain phenyl dichlorophosphate-grafted carbon fiber; Step (3): Under an inert gas atmosphere, add 2-(2-hydroxyphenyl)-5-amino-2H-benzotriazole, phenyl dichlorophosphate-grafted carbon fiber, and potassium carbonate to N,N-dimethylformamide, heat and react. After the reaction ends, filter, wash, and dry to obtain a functional filler; Step (4): Mix epoxy resin, functional filler, and catalyst, stir, heat for reaction. After the reaction ends, obtain Intermediate I; Mix Intermediate I, curing agent, and antioxidant, heat in a water bath, perform ultrasonic oscillation, stir evenly, and after curing, obtain a high-temperature resistant carbon fiber composite.

[0006] Preferably, the preparation method of the reduced carbon fiber includes the following steps: S1: Add carbon fiber to an acid solution, stir for oxidation, wash until neutral, and dry under vacuum to obtain acid-oxidized carbon fiber; S2: Heat and reflux the carbon fiber obtained in S1 in a saturated solution of LiAlH 4 -tetrahydrofuran, wash, and dry to obtain reduced carbon fiber.

[0007] Preferably, the dosage ratio of carbon fiber to acid solution is (0.5 - 1.7 g):(180 - 240 mL).

[0008] Preferably, the acid solution includes an 80% sulfuric acid aqueous solution and a 60% nitric acid aqueous solution, and the volume ratio of the sulfuric acid aqueous solution to the nitric acid aqueous solution is 1:1.

[0009] Preferably, the stirring oxidation is specifically: stirring at 50 - 70 °C and a rotation speed of 100 - 180 r / min for 6 - 8 h.

[0010] Preferably, in S1, the drying conditions are: drying at -0.08 MPa and a temperature of 60 - 80 °C for 8 - 12 h.

[0011] Preferably, in S2, the reflux temperature is 60 - 80 °C; the heating reflux time is: 2 - 6 h.

[0012] Preferably, in S2, the drying conditions are: drying at a temperature of 80 - 100 °C for 6 - 8 h.

[0013] Preferably, in step (1), the mass ratio of the reduced carbon fiber, amino silane coupling agent, and toluene is (80 - 100):(30 - 50):(1000 - 1600).

[0014] Preferably, the amino silane coupling agent includes any one of γ-aminopropyltriethoxysilane, N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane, γ-aminopropyltrimethoxysilane, and γ-aminopropyltriethoxysilane.

[0015] Preferably, in step (1), the first heating temperature is 18 - 42 °C, and the reaction time is 3 - 5 h; the conditions for heating under reflux are: reacting at a temperature of 80 - 100 °C for 1 - 5 h.

[0016] Preferably, in step (2), the mass ratio of phenyl dichlorophosphate, triethylamine, toluene, and amino-modified carbon fiber is (160 - 200):(18 - 30):(1000 - 1800):(40 - 80); the reaction temperature is 70 - 90 °C, and the reaction time is 24 - 28 h.

[0017] Preferably, in step (3), the mass ratio of 2-(2-hydroxyphenyl)-5-amino-2H-benzotriazole, phenyl dichlorophosphate grafted carbon fiber, potassium carbonate, and N,N-dimethylformamide is (180 - 220):(460 - 580):(70 - 90):(1600 - 2800); the reaction temperature is 45 - 65 °C, and the reaction time is 34 - 46 h.

[0018] Preferably, in step (4), the reaction temperature is 100 - 120 °C, and the reaction time is 6 - 8 h.

[0019] Preferably, in step (4), the mass ratio of epoxy resin, functional filler, catalyst, curing agent, and antioxidant is 100:(20 - 30):(2 - 5):(10 - 18):(1 - 3).

[0020] Preferably, in step (4), the catalyst is triethylamine.

[0021] Preferably, the antioxidant is one of antioxidant 1076, antioxidant 1010, and antioxidant 168.

[0022] Preferably, the water bath temperature is 70 - 80 °C, and the time is 1 - 2 h.

[0023] Preferably, the curing temperature is 160 - 180 °C, and the time is 3 - 5 h.

[0024] Preferably, a high-temperature resistant carbon fiber composite material prepared by the preparation method of the high-temperature resistant carbon fiber composite material described above.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. In the present invention, the dispersibility and compatibility of the modified carbon fiber in the matrix are improved. The introduction of the amino-silane coupling agent, with a relatively large silicon-oxygen bond energy, increases the high-temperature resistance to a certain extent. The amino group in the amino-modified carbon fiber reacts with the chloro group in the flame-retardant phenyl dichlorophosphate to form a P-N bond, and the two are connected by a covalent bond to obtain phenyl dichlorophosphate-grafted carbon fiber, introducing phosphorus element onto the carbon fiber surface. Since phosphorus itself has flame retardancy, the flame retardancy is further improved. 2-(2-Hydroxyphenyl)-5-amino-2H-benzotriazole has a benzotriazole structure, which has excellent heat resistance and antioxidant properties and can improve the high-temperature resistance of the composite material. Its active functional groups include hydroxyl and amino groups, and the hydroxyl group therein chemically reacts with the chloro group in the phenyl dichlorophosphate-grafted carbon fiber to obtain a functional filler with better chemical resistance. The amino group in the functional filler can further react with epoxy resin under the action of a catalyst, and the two are connected by a covalent bond, with better compatibility and better interfacial bonding. In the present invention, a multi-functional interface layer is constructed on the carbon fiber surface. This interface layer can not only form a strong chemical bond with the carbon fiber but also react with epoxy resin, thereby realizing the effective connection between the carbon fiber and the epoxy resin and improving the mechanical properties of the composite material.

[0026] 2. In the present invention, the modified carbon fiber is more likely to form a carbon layer during the combustion process. The carbon layer can effectively block heat transfer and the release of combustible gases; phenyl dichlorophosphate contains phosphorus element, and phosphorus can form phosphoric acid or metaphosphoric acid during combustion. These substances can cover the material surface to form a protective layer to prevent oxygen from entering, thereby playing a flame-retardant role. In addition, phosphorus can also promote the carbonization of the material to form a carbon layer to block the release of heat and combustible gases; 2-(2-Hydroxyphenyl)-5-amino-2H-benzotriazole contains nitrogen element, which can release non-combustible gases such as nitrogen during combustion to dilute the oxygen concentration in the combustion area, thereby inhibiting combustion; through the modification of the carbon fiber surface, its dispersibility and compatibility are improved, enabling the flame-retardant elements to be more evenly dispersed in the epoxy resin matrix, playing a synergistic role and improving the flame retardancy of the material. Specific Embodiments

[0027] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0028] Example 1 This embodiment provides a preparation method of a high-temperature resistant carbon fiber composite material, comprising the following steps: Step (1) Under a nitrogen atmosphere, reduced carbon fiber, γ-aminopropyltriethoxysilane and toluene are mixed in a mass ratio of 80:30:1000, reacted at 18 °C for 5 h, continuously heated to 80 °C and refluxed for 5 h, cooled to room temperature, washed with absolute ethanol, filtered, and dried at 60 °C for 10 h to obtain amino-modified carbon fiber; Step (2) Dichlorophenyl phosphate, triethylamine, toluene and amino-modified carbon fiber are mixed in a mass ratio of 160:18:1000:40, reacted at 70 °C for 28 h, after the reaction ends, filtered, washed 3 times with deionized water, and dried at 100 °C for 7 h to obtain dichlorophenyl phosphate-grafted carbon fiber; Step (3) Under an inert gas atmosphere, 2-(2-hydroxyphenyl)-5-amino-2H-benzotriazole, dichlorophenyl phosphate-grafted carbon fiber, potassium carbonate and N,N-dimethylformamide are mixed in a mass ratio of 180:460:70:1600, reacted at 45 °C for 46 h, after the reaction ends, filtered, washed with absolute ethanol, and dried at 100 °C for 6 h to obtain a functional filler; Step (4) Epoxy resin, functional filler and triethylamine are mixed, stirred at a speed of 200 r / min for 6 min, reacted at 100 °C for 8 h, after the reaction ends, to obtain Intermediate I; Intermediate I, ethylenediamine and antioxidant 168 are mixed, water-bathed at 70 °C for 2 h, ultrasonically oscillated at a frequency of 40 kHz for 26 min, and cured at 160 °C for 5 h to obtain a high-temperature resistant carbon fiber composite material; Wherein, the mass ratio of epoxy resin, functional filler, triethylamine, ethylenediamine and antioxidant 168 is 100:20:2:10:1.

[0029] Example 2 This embodiment provides a preparation method of a high-temperature resistant carbon fiber composite material, comprising the following steps: Step (1) Under a nitrogen atmosphere, reduced carbon fiber, γ-aminopropyltriethoxysilane and toluene are mixed in a mass ratio of 85:35:1150, reacted at 24 °C for 4.5 h, continuously heated to 85 °C and refluxed for 4 h, cooled to room temperature, washed with absolute ethanol, filtered, and dried at 65 °C for 9.5 h to obtain amino-modified carbon fiber; Step (2): Mix phenyl dichlorophosphate, triethylamine, toluene, and amino-modified carbon fiber in a mass ratio of 170:21:1200:50, react at 75 °C for 27 h. After the reaction, filter, wash with deionized water three times, and dry at 105 °C for 6.5 h to obtain phenyl dichlorophosphate-grafted carbon fiber; Step (3): Under an inert gas atmosphere, mix 2-(2-hydroxyphenyl)-5-amino-2H-benzotriazole, phenyl dichlorophosphate-grafted carbon fiber, potassium carbonate, and N,N-dimethylformamide in a mass ratio of 190:490:75:1900, react at 50 °C for 43 h. After the reaction, filter, wash with absolute ethanol, and dry at 105 °C for 5.5 h to obtain the functional filler; Step (4): Mix epoxy resin, functional filler, and triethylamine, stir at a speed of 250 r / min for 5.5 min, and react at 105 °C for 7.5 h. After the reaction, obtain Intermediate I; Mix Intermediate I, ethylenediamine, and antioxidant 168, carry out a water bath at 72 °C for 1.8 h, perform ultrasonic oscillation at a frequency of 42 kHz for 24 min, and cure at 165 °C for 4.5 h to obtain the high-temperature resistant carbon fiber composite; Among them, the mass ratio of epoxy resin, functional filler, triethylamine, ethylenediamine, and antioxidant 168 is 100:22:2.7:12:1.5.

[0030] Example 3 This example provides a method for preparing a high-temperature resistant carbon fiber composite, including the following steps: Step (1): Under a nitrogen atmosphere, mix reduced carbon fiber, γ-aminopropyltriethoxysilane, and toluene in a mass ratio of 90:40:1300, react at 30 °C for 4 h, continue to heat to 90 °C and carry out a reflux reaction for 3 h, cool to room temperature, wash with absolute ethanol, filter, and dry at 70 °C for 9 h to obtain amino-modified carbon fiber; Step (2): Mix phenyl dichlorophosphate, triethylamine, toluene, and amino-modified carbon fiber in a mass ratio of 180:24:1400:60, react at 80 °C for 26 h. After the reaction, filter, wash with deionized water three times, and dry at 110 °C for 6 h to obtain phenyl dichlorophosphate-grafted carbon fiber; Step (3): Under an inert gas atmosphere, mix 2-(2-hydroxyphenyl)-5-amino-2H-benzotriazole, phenyl dichlorophosphate-grafted carbon fiber, potassium carbonate, and N,N-dimethylformamide in a mass ratio of 200:520:80:2200, react at 55 °C for 40 h. After the reaction, filter, wash with absolute ethanol, and dry at 110 °C for 5 h to obtain the functional filler; Step (4): Mix epoxy resin, functional filler and triethylamine, stir at a rotation speed of 300 r / min for 5 min, react at a temperature of 110 °C for 7 h, and after the reaction ends, obtain Intermediate I; Mix Intermediate I, ethylenediamine and antioxidant 168, perform water bath at a temperature of 75 °C for 1.5 h, carry out ultrasonic oscillation at a frequency of 45 kHz for 22 min, and cure at a temperature of 170 °C for 4 h to obtain a high-temperature resistant carbon fiber composite material; Among them, the mass ratio of epoxy resin, functional filler, triethylamine, ethylenediamine and antioxidant 168 is 100:25:3.5:14:2.

[0031] Example 4 This example provides a preparation method of a high-temperature resistant carbon fiber composite material, including the following steps: Step (1): Under a nitrogen atmosphere, mix the reduced carbon fiber, γ-aminopropyltriethoxysilane and toluene according to a mass ratio of 95:45:1450, react at a temperature of 36 °C for 3.5 h, continue to heat to 95 °C and carry out reflux reaction for 2 h, cool to room temperature, wash with absolute ethanol, filter, and dry at a temperature of 75 °C for 8.5 h to obtain amino-modified carbon fiber; Step (2): Mix dichlorophenyl phosphate, triethylamine, toluene and amino-modified carbon fiber according to a mass ratio of 190:27:1600:70, react at a temperature of 85 °C for 25 h, after the reaction ends, filter, wash with deionized water 3 times, and dry at a temperature of 115 °C for 5.5 h to obtain dichlorophenyl phosphate-grafted carbon fiber; Step (3): Under an inert gas atmosphere, mix 2-(2-hydroxyphenyl)-5-amino-2H-benzotriazole, dichlorophenyl phosphate-grafted carbon fiber, potassium carbonate and N,N-dimethylformamide according to a mass ratio of 210:550:85:2500, react at a temperature of 60 °C for 37 h, after the reaction ends, filter, wash with absolute ethanol, and dry at 115 °C for 4.5 h to obtain a functional filler; Step (4): Mix epoxy resin, functional filler and triethylamine, stir at a rotation speed of 350 r / min for 4.5 min, react at a temperature of 115 °C for 6.5 h, and after the reaction ends, obtain Intermediate I; Mix Intermediate I, ethylenediamine and antioxidant 168, perform water bath at a temperature of 77 °C for 1.2 h, carry out ultrasonic oscillation at a frequency of 47 kHz for 20 min, and cure at a temperature of 175 °C for 3.5 h to obtain a high-temperature resistant carbon fiber composite material; Among them, the mass ratio of epoxy resin, functional filler, triethylamine, ethylenediamine and antioxidant 168 is 100:27:4.2:16:2.5.

[0032] Example 5 This embodiment provides a preparation method of a high-temperature resistant carbon fiber composite material, comprising the following steps: Step (1) Under a nitrogen atmosphere, reduced carbon fiber, γ-aminopropyltriethoxysilane and toluene are mixed in a mass ratio of 100:50:1600, reacted at 42 °C for 3 h, continuously heated to 100 °C and refluxed for 1 h, cooled to room temperature, washed with absolute ethanol, filtered, and dried at 80 °C for 8 h to obtain amino-modified carbon fiber; Step (2) Diphenyl phosphorochloridate, triethylamine, toluene and amino-modified carbon fiber are mixed in a mass ratio of 200:30:1800:80, reacted at 90 °C for 24 h, after the reaction, filtered, washed 3 times with deionized water, and dried at 120 °C for 5 h to obtain diphenyl phosphorochloridate-grafted carbon fiber; Step (3) Under an inert gas atmosphere, 2-(2-hydroxyphenyl)-5-amino-2H-benzotriazole, diphenyl phosphorochloridate-grafted carbon fiber, potassium carbonate and N,N-dimethylformamide are mixed in a mass ratio of 220:580:90:2800, reacted at 65 °C for 34 h, after the reaction, filtered, washed with absolute ethanol, and dried at 120 °C for 4 h to obtain a functional filler; Step (4) Epoxy resin, functional filler and triethylamine are mixed, stirred at a speed of 400 r / min for 4 min, reacted at 120 °C for 6 h, after the reaction, intermediate I is obtained; Intermediate I, ethylenediamine and antioxidant 168 are mixed, water-bathed at 80 °C for 1 h, ultrasonically oscillated at a frequency of 50 kHz for 18 min, and cured at 180 °C for 3 h to obtain a high-temperature resistant carbon fiber composite material; Among them, the mass ratio of epoxy resin, functional filler, triethylamine, ethylenediamine and antioxidant 168 is 100:30:5:18:3.

[0033] Example 6 This embodiment provides a preparation method of reduced carbon fiber, comprising the following steps: S1: Carbon fiber and acid solution are mixed in a dosage ratio of 0.5 g:180 mL, stirred at 50 °C and 100 r / min for 8 h, washed with deionized water until neutral, and dried at -0.08 MPa and 60 °C for 12 h to obtain acid-oxidized carbon fiber; Among them, the acid solution includes 80% sulfuric acid aqueous solution and 60% nitric acid aqueous solution, and the volume ratio of sulfuric acid aqueous solution to nitric acid aqueous solution is 1:1; S2: The carbon fiber obtained in S1 and LiA1H 4A saturated solution of tetrahydrofuran is mixed in a mass ratio of 3:10, heated under reflux at 60 °C for 6 h, washed with deionized water, and dried at 80 °C for 8 h to obtain the reduced carbon fiber.

[0034] Comparative Example 1 This comparative example provides a method for preparing a high-temperature resistant carbon fiber composite, including the following steps: Step (1) Under a nitrogen atmosphere, the reduced carbon fiber, γ-aminopropyltriethoxysilane, and toluene are mixed in a mass ratio of 80:30:1000, reacted at 18 °C for 5 h, continuously heated to 80 °C and refluxed for 5 h, cooled to room temperature, washed with absolute ethanol, filtered, and dried at 60 °C for 10 h to obtain the amino-modified carbon fiber; Step (2) Diphenyl phosphate dichloride, triethylamine, toluene, and the amino-modified carbon fiber are mixed in a mass ratio of 160:18:1000:40, reacted at 70 °C for 28 h, after the reaction, filtered, washed 3 times with deionized water, and dried at 100 °C for 7 h to obtain the diphenyl phosphate dichloride-grafted carbon fiber; Step (3) Under an inert gas atmosphere, 2-(2-hydroxyphenyl)-5-amino-2H-benzotriazole, the diphenyl phosphate dichloride-grafted carbon fiber, potassium carbonate, and N,N-dimethylformamide are mixed in a mass ratio of 180:460:70:1600, reacted at 45 °C for 46 h, after the reaction, filtered, washed with absolute ethanol, and dried at 100 °C for 6 h to obtain the functional filler; Step (4) Epoxy resin, the functional filler, ethylenediamine, and antioxidant 168 are mixed, water-bathed at 70 °C for 2 h, ultrasonically oscillated at a frequency of 40 kHz for 26 min, and cured at 160 °C for 5 h to obtain the high-temperature resistant carbon fiber composite; Among them, the mass ratio of the epoxy resin, the functional filler, ethylenediamine, and antioxidant 168 is 102:20:10:1.

[0035] Comparative Example 2 This comparative example provides a method for preparing a high-temperature resistant carbon fiber composite, including the following steps: Step (1) Under a nitrogen atmosphere, the reduced carbon fiber, γ-aminopropyltriethoxysilane, and toluene are mixed in a mass ratio of 80:30:1000, reacted at 18 °C for 5 h, continuously heated to 80 °C and refluxed for 5 h, cooled to room temperature, washed with absolute ethanol, filtered, and dried at 60 °C for 10 h to obtain the amino-modified carbon fiber; Step (2): Mix phenyl dichlorophosphate, triethylamine, toluene, and amino-modified carbon fiber in a mass ratio of 160:18:1000:40, react at 70 °C for 28 h. After the reaction, filter, wash with deionized water three times, and dry at 100 °C for 7 h to obtain phenyl dichlorophosphate-grafted carbon fiber; Step (3): Mix epoxy resin, phenyl dichlorophosphate-grafted carbon fiber, ethylenediamine, and antioxidant 168, perform a water bath at 70 °C for 2 h, ultrasonically oscillate at a frequency of 40 kHz for 26 min, and cure at 160 °C for 5 h to obtain a high-temperature resistant carbon fiber composite; Among them, the mass ratio of epoxy resin, phenyl dichlorophosphate-grafted carbon fiber, ethylenediamine, and antioxidant 168 is 102:20:10:1.

[0036] Comparative Example 3 This comparative example provides a method for preparing a high-temperature resistant carbon fiber composite, including the following steps: Step (1): Under a nitrogen atmosphere, mix reduced carbon fiber, γ-aminopropyltriethoxysilane, and toluene in a mass ratio of 80:30:1000, react at 18 °C for 5 h, continue to heat to 80 °C and carry out a reflux reaction for 5 h, cool to room temperature, wash with absolute ethanol, filter, and dry at 60 °C for 10 h to obtain amino-modified carbon fiber; Step (2): Mix phenyl dichlorophosphate, triethylamine, toluene, and amino-modified carbon fiber in a mass ratio of 160:18:1000:40, react at 70 °C for 28 h. After the reaction, filter, wash with deionized water three times, and dry at 100 °C for 7 h to obtain phenyl dichlorophosphate-grafted carbon fiber; Step (3): Mix epoxy resin, phenyl dichlorophosphate, amino-modified carbon fiber, ethylenediamine, and antioxidant 168, perform a water bath at 70 °C for 2 h, ultrasonically oscillate at a frequency of 40 kHz for 26 min, and cure at 160 °C for 5 h to obtain a high-temperature resistant carbon fiber composite; Among them, the mass ratio of epoxy resin, phenyl dichlorophosphate, amino-modified carbon fiber, ethylenediamine, antioxidant 168, and polyacrylate is 102:16:4:10:1.

[0037] In the present invention, the reduced carbon fibers in Examples 1-5 and Comparative Examples 1-3 are all the reduced carbon fibers prepared in Example 6.

[0038] In the present invention, the carbon fiber is from Shanghai Xiaohuang Nano Technology Co., Ltd.; phenyl dichlorophosphate is from Shaoguan Chengfeng Chemical Industry Co., Ltd., CAS No.: 770-12-7; triethylamine is from Shanghai Aladdin Biochemical Technology Co., Ltd., CAS No.: 121-44-8; the epoxy resin is from Wuxi Qianguang Chemical Raw Materials Co., Ltd., with a solid content of 100 (%) and a viscosity of 18,000 - 28,000 (mPas).

[0039] The high-temperature resistant carbon fiber composites prepared in Examples 1-5 and Comparative Examples 1-3 were subjected to corresponding tests, and the test results are as follows: (1) Mechanical property test: The high-temperature resistant carbon fiber composites prepared in Examples 1-5 and Comparative Examples 1-3 were made into specimens with dimensions of 80 mm × 10 mm × 4 mm for mechanical property testing; tensile strength testing was carried out on a BJDW universal testing machine, with each group repeated 3 times and the average value taken; the specific test results are shown in Table 1; (2) Heat aging property test: The high-temperature resistant carbon fiber composites prepared in Examples 1-5 and Comparative Examples 1-3 were made into specimens with dimensions of 80 mm × 10 mm × 4 mm. The samples were respectively placed in a heat aging test chamber for 10 days of aging treatment at a temperature of 200 °C. After the treatment, the samples were taken out and subjected to the same mechanical property tests as in Table 1. Each sample was tested 5 times and the average value was taken; the corresponding test data are shown in Table 1: Table 1

[0040] According to the test results in Table 1, it can be seen that the high-temperature resistant carbon fiber composites prepared in the present invention have good tensile properties. The average tensile strength of the high-temperature resistant carbon fiber composites in Examples 1-5 is 62.44 MPa, and after thermal-oxidative aging, especially in Example 5, good tensile strength is maintained, with a retention rate of 87.5%. In Comparative Example 1 compared with Example 1, there is no covalent bond connection between the epoxy resin and the functional filler, the binding force between the two is reduced, and the dispersion of the functional filler in the epoxy resin is not as good as that in Comparative Example 1. Therefore, the tensile property of Example 1 is better than that of Comparative Example 1; in Comparative Example 2 compared with Comparative Example 1, 2-(2-hydroxyphenyl)-5-amino-2H-benzotriazole is missing, the active sites for reacting with the epoxy resin are missing, the crosslinking degree is reduced, the tensile property is reduced, and 2-(2-hydroxyphenyl)-5-amino-2H-benzotriazole itself has certain heat resistance, and once it is missing, the heat resistance decreases; in Comparative Example 3 compared with Comparative Example 2, phenyl dichlorophosphate, amino-modified carbon fiber and epoxy resin are mixed, there will be problems of uneven dispersion and poor interfacial bonding, and the tensile property and heat aging property of Comparative Example 3 are both lower than those of Comparative Example 2.

[0041] (3) Flame retardancy test: The test method refers to the oxygen index method - test method for combustion performance of plastics in GB / T 2406.2-2009. The test results are shown in Table 2 as follows: Table 2

[0042] According to the test results in Table 2, it can be seen that when the modified carbon fiber is added to the epoxy resin, it will increase the heat resistance and flame retardancy to a certain extent. Its dispersion performance and compatibility are better, and its heat resistance and flame retardancy are naturally better. The high-temperature resistant carbon fiber composite material prepared by the present invention shows the best flame retardancy performance in Example 5. In Comparative Example 1 compared with Example 1, the dispersion and compatibility of the functional filler in the epoxy resin are not as good as those in Comparative Example 1, so the flame retardancy performance is lower than that of Example 1. In Comparative Example 2 compared with Comparative Example 1, 2-(2-hydroxyphenyl)-5-amino-2H-benzotriazole containing nitrogen element is missing. The nitrogen element contained can generate nitrogen-containing non-combustible gases during the combustion process of the matrix, effectively diluting the concentration of oxygen in the combustion system and slowing down the progress of the combustion reaction, playing a flame retardant effect. Once it is missing, the flame retardancy performance will naturally decrease. In Comparative Example 3 compared with Comparative Example 2, phenyl dichlorophosphate and amino-modified carbon fiber have a certain flame retardant effect. At the same time, the HCl gas formed by the chlorine element in phenyl dichlorophosphate during the combustion process can play a role in interrupting the chain reaction of combustion, slowing down or even preventing the continuation of combustion, which is beneficial to flame retardancy. However, its dispersion is not as good as that in Comparative Example 2. Generally speaking, the flame retardancy performance of Comparative Example 3 is lower than that of Comparative Example 2.

[0043] (4) High-temperature resistance test: The high-temperature resistant carbon fiber composite materials prepared in Examples 1-5 and Comparative Examples 1-3 are made into specimens with dimensions of 15 mm × 15 mm × 3 mm in length, width and height, placed in an oven, heated to 150 °C, and the shear strength of the specimens is measured. Repeat 3 times and record the average value. The specific results are shown in Table 3 as follows; Table 3

[0044] According to the test results in Table 3, it can be seen that the high-temperature resistant carbon fiber composite materials prepared in Examples 1-5 have good heat resistance performance, which is better than those in Comparative Examples 1-3.

[0045] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principle and spirit of the present invention. All equivalent changes and improvements made according to the scope of the present invention application should still fall within the scope covered by the patent of the present invention.

Claims

1. A method for preparing a high temperature resistant carbon fiber composite material, characterized in that: The following steps are involved: Step (1) under a nitrogen atmosphere, adding the reduced carbon fiber and the aminosilane coupling agent to toluene, heating for reaction and keeping the temperature, continuing heating for reflux reaction, cooling, washing, filtering, and drying to obtain amino-modified carbon fiber; Step (2) adding phenyl dichloride phosphate and triethylamine to toluene, stirring, adding amino-modified carbon fiber, heating, reacting, filtering, washing, and drying after the reaction is completed to obtain phenyl dichloride phosphate grafted carbon fiber; Step (3) under an inert gas atmosphere, adding 2-(2-hydroxyphenyl)-5-amino-2H-benzotriazole, phenyl dichloride phosphate grafted carbon fiber and potassium carbonate to N,N-dimethylformamide, heating, reacting, filtering, washing and drying after the reaction is completed to obtain a functional filler; Step (4) mixing the epoxy resin, the functional filler and the catalyst, stirring, heating and reacting, and completing the reaction to obtain an intermediate I; The intermediate I, curing agent and antioxidant are mixed, heated in a water bath, ultrasonically vibrated, stirred evenly, and cured to obtain a high temperature resistant carbon fiber composite material.

2. The method for preparing a high temperature resistant carbon fiber composite material according to claim 1, characterized in that: The method for preparing the reduced carbon fiber comprises the following steps: S1: adding carbon fiber to an acid solution, stirring and oxidizing, washing to neutrality, and vacuum drying to obtain acid-oxidized carbon fiber; S2: The carbon fiber obtained in S1 is heated to reflux in a saturated solution of LiA1H4-tetrahydrofuran, washed, and dried to obtain reduced carbon fiber.

3. The method for preparing a high temperature resistant carbon fiber composite material according to claim 1, characterized in that: In step (1), the mass ratio of the reduced carbon fiber, the aminosilane coupling agent and toluene is (80-100):(30-50):(1000-1600).

4. The method for preparing a high temperature resistant carbon fiber composite material according to claim 1, characterized in that: In step (1), the first heating temperature is 18-42°C and the reaction time is 3-5h; the heating reflux reaction conditions are: reacting at 80-100°C for 1-5h.

5. The method for preparing a high temperature resistant carbon fiber composite material according to claim 1, characterized in that: In step (2), the mass ratio of phenyl dichloride phosphate, triethylamine, toluene and amino-modified carbon fiber is (160-200):(18-30):(1000-1800):(40-80); the reaction temperature is 70-90°C, and the reaction time is 24-28h.

6. The method for preparing a high temperature resistant carbon fiber composite material according to claim 1, characterized in that: In step (3), the mass ratio of 2-(2-hydroxyphenyl)-5-amino-2H-benzotriazole, dichlorophenyl phosphate grafted carbon fiber, potassium carbonate and N,N-dimethylformamide is (180-220):(460-580):(70-90):(1600-2800); the reaction temperature is 45-65°C, and the reaction time is 34-46h.

7. The method for preparing a high temperature resistant carbon fiber composite material according to claim 1, characterized in that: In step (4), the reaction temperature is 100-120°C and the reaction time is 6-8h.

8. The method for preparing a high temperature resistant carbon fiber composite material according to claim 1, characterized in that: In step (4), the mass ratio of epoxy resin, functional filler, catalyst, curing agent and antioxidant is 100:(20-30):(2-5):(10-18):(1-3).

9. The method for preparing a high temperature resistant carbon fiber composite material according to claim 1, characterized in that: In step (4), the catalyst is triethylamine.

10. A high temperature resistant carbon fiber composite material prepared by the method for preparing a high temperature resistant carbon fiber composite material according to any one of claims 1 to 9.

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