Preparation method, product and application of organic-inorganic hybrid structure constructed by using carbon fiber surface

Abstract

The present invention relates to the technical field of carbon fiber interface modification, specifically a preparation method, product and application of an organic-inorganic hybrid structure constructed on the surface of carbon fiber. The present invention desizes carbon fiber in acetone to obtain desized carbon fiber; prepares MPN solution and CNTs suspension respectively; soaks the desized carbon fiber in MPN solution and CNTs suspension respectively, and then ultrasonically oscillates and dries to obtain a metal polyphenol network and a carbon nanotube-coated carbon fiber; mixes the MPN solution and CNTs suspension evenly, soaks the desized carbon fiber in the MPN and CNTs mixed solution, and then ultrasonically oscillates and dries to obtain a metal polyphenol network and a carbon nanotube-coated carbon fiber. The present invention coats the surface of carbon fiber with carbon nanotubes and metal polyphenol networks, utilizes the advantages of both parties, realizes the construction of an organic-inorganic hybrid structure on the surface of carbon fiber, and improves product performance.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon fiber interface modification, and in particular to a preparation method, product and application of an organic-inorganic hybrid structure constructed on the surface of carbon fiber. Background Art

[0002] Carbon fiber reinforced resin-based composites (CFRP) have excellent properties such as high specific strength, high specific modulus, fatigue resistance, corrosion resistance, designability, and integrated structural molding, and have been widely used in the aerospace industry. However, due to the influence of the production process, the surface of carbon fiber is smooth and chemically inert. After compounding with the resin, the interface area is prone to damage such as interface debonding and matrix fracture, which greatly affects the impact strength, structural toughness and service life of CFRP. Therefore, in order to meet the strength requirements of carbon fiber composites in practical applications, the carbon fiber surface must be modified, usually by physical or chemical effects to increase the surface roughness and polar functional groups of the carbon fiber and improve the wettability of the resin matrix to the fiber surface. The interface properties of the composite material are enhanced by introducing chemical bonding and mechanical meshing in the interface phase.

[0003] Polyphenols have a rich variety of functional groups, such as catechol and galloyl, which can interact with other molecules in a variety of ways. Carbon nanotubes (CNTs) are a unique one-dimensional quantum material. They are concentric tubes composed of hexagonally arranged carbon atoms with diameters of up to dozens of nanometer layers. They have potential applications in carbon fiber surface modification.

[0004] Existing methods for modifying carbon fibers lack reports on methods that utilize the strong adhesion of metal polyphenol networks and the strong π-π conjugation of carbon nanotubes to rapidly and orderly self-assemble "organic-inorganic" hybrid structures on the carbon fiber surface. Furthermore, there is limited research on the application of metal polyphenol networks and carbon nanotube-coated carbon fibers in composite materials. Therefore, a simple, low-cost method for constructing organic-inorganic hybrid structures on the carbon fiber surface is urgently needed. Summary of the Invention

[0005] To solve the above problems, the present invention provides a preparation method, product and application of an organic-inorganic hybrid structure constructed on the surface of carbon fiber. The preparation process is simple, the cost is low, it is green and environmentally friendly, and the product performance is excellent.

[0006] The first object of the present invention is to provide a preparation method for constructing an organic-inorganic hybrid structure using the surface of carbon fiber, the preparation method comprising the following steps:

[0007] Step 1: Desizing the carbon fiber in acetone to obtain desizing carbon fiber; the amount of acetone used is sufficient to ensure the desizing of the carbon fiber, such as 1-5 times the mass of the carbon fiber. Step 2: Dissolving tannic acid and FeCl3·6H2O in deionized water, stirring and mixing to obtain a metal polyphenol network solution, i.e., an MPN solution; the molar ratio of tannic acid to FeCl3·6H2O is 1:1-3;

[0008] Step 3: dissolving carbon nanotubes in deionized water and ultrasonically obtaining a carbon nanotube suspension, i.e., a CNTs suspension;

[0009] Step 4: The desized carbon fiber is first placed in the MPN solution for ultrasonic impregnation, rinsed, and then the MPN-coated carbon fiber is placed in the CNTs suspension for ultrasonic impregnation, rinsed again, and the above operation is repeated until the supernatant is colorless and transparent, and then dried to obtain a metal polyphenol network and carbon nanotube-coated carbon fiber;

[0010] The mass ratio of the tannic acid to the carbon nanotubes is 4.25:0.05-0.15.

[0011] This solution is further improved. In step 1, the acetone desizing temperature is 60° C. to 80° C., and the desizing time is 36 to 72 hours.

[0012] This solution is further improved. In step 2, the mass volume ratio of tannic acid to deionized water (g:ml) is 4.25:200; the mixture is stirred and mixed with a magnetic stirrer for 5-15 minutes at a stirring rate of 900-1200 r / min; the tannic acid and Fe in the obtained MPN solution are 3+ The molar ratio is 1:1~3.

[0013] This solution is further improved. In step 3, the ultrasonic frequency is 80 to 120 kHz, more preferably 90 to 110 kHz; more preferably 100 kHz; and the ultrasonic time is 5 to 30 minutes.

[0014] This solution is further improved, in which the ultrasonic frequency in step 4 is 80-120 kHz, more preferably 90-110 kHz; more preferably 100 kHz; the ultrasonic immersion is 5-20 min min, the drying temperature is 50-70°C; the drying time is 5-7 h; the number of immersion cycles is 1-3 times, preferably 1 time, and the number of cleanings is preferably 3-5 times.

[0015] This solution is further improved. In step 4, the mass ratio of the MPN solution to the CNTs suspension is 1-2:1-2, preferably 1:1; the mass ratio of the desized carbon fiber to the tannic acid in step 2 is 10:4.25.

[0016] This solution can be further improved to include the following steps:

[0017] Step 1: Place the carbon fiber in a Soxhlet extractor, add acetone, heat to 68°C, react for 48 hours, take it out after the reaction is completed, wash it with deionized water 5 times, and dry it to obtain desized carbon fiber;

[0018] Step 2: Dissolve 4.25g of tannic acid and 2.03g of FeCl3·6H2O powder in 200ml of deionized water, stir and mix with a magnetic stirrer for 10min at a stirring rate of 1000r / min to obtain TA and Fe 3+ a metal polyphenol network solution with a molar ratio of 1:3;

[0019] Step 3: Dissolve 0.1 g of carbon nanotubes in 200 ml of deionized water and ultrasonicate at 100 kHz for 30 min to obtain a carbon nanotube suspension;

[0020] Step 4: Place 10g of desized carbon fiber in the MPN solution and ultrasonically immerse it for 10 minutes, then rinse it with deionized water three times, then place the MPN-coated carbon fiber in the CNTs suspension and ultrasonically immerse it for 10 minutes, and rinse it with deionized water three times again until the supernatant is colorless and transparent, then place it in a drying oven and dry it at 60°C for 6 hours to obtain a metal polyphenol network and carbon nanotube-coated carbon fiber.

[0021] In a second aspect, the present invention provides a metal polyphenol network and carbon nanotube-coated carbon fiber obtained by the above method.

[0022] In a third aspect, the present invention provides an application of a metal polyphenol network and carbon nanotube-coated carbon fibers in a composite material. The metal polyphenol network and carbon nanotube-coated carbon fibers are compounded with epoxy resin and the composite material is prepared by a molding process.

[0023] This scheme is further improved, the metal polyphenol network and the carbon nanotube-coated carbon fiber account for 63% of the volume fraction of the composite material; the metal polyphenol network and the carbon nanotube-coated carbon fiber are fully impregnated in the epoxy resin E51, the temperature of the vulcanizer is adjusted to 90°C, and the mold wrapped with the metal polyphenol network and the carbon nanotube-coated carbon fiber impregnated with the resin is placed in the vulcanizer for preheating, and then the pressure is adjusted to 5MPa through the pressure control system, the molding system is started, and maintained at 90°C and 5MPa for 1h; then the temperature is adjusted to 120°C and the pressure is 10MPa, and maintained for 2h; finally, the temperature is adjusted to 150°C and the pressure is 10MPa, and maintained for 3h; after the molding is completed, it is naturally cooled to room temperature under the pressure holding state, and demolded to obtain a composite material.

[0024] The beneficial effects of the present invention are:

[0025] (1) The present invention provides a preparation method for constructing an organic-inorganic hybrid structure using the surface of carbon fiber. The preparation method is simple, environmentally friendly, low-cost, and effectively shortens the preparation time, making it suitable for promotion and application.

[0026] (2) Since carbon nanotubes are tubular, when they are dispersed into the coating, they easily form a dense network structure, reducing the pores in the coating. Therefore, using carbon nanotubes to modify carbon fibers increases the surface roughness of the fibers, which can effectively improve their mechanical properties and enhance the interfacial bonding between them and the matrix, thereby improving their overall performance. In addition, carbon nanotubes (CNTs) can be embedded in the resin matrix to increase the mechanical engagement between the fibers and the resin matrix.

[0027] Tannic acid (TA) is a natural compound polyphenol. The pyrogallol hydroxyl group in the molecular structure has high affinity, and the coupling groups in tannic acid (TA) can form oligomers through hydrogen bonds or π-π bond stacking interactions. Tannic acid (TA) and Fe 3+ The metal polyphenol network (MPN) material formed by complexation has the characteristics of large pore size and specific surface area, so Fe 3+ The invention uses carbon nanotubes and metal polyphenol networks coated on carbon fiber surfaces, leveraging the advantages of both, creating a synergistic effect and constructing an organic-inorganic hybrid structure on the carbon fiber surface, thereby improving product performance.

[0028] (3) The present invention provides a preparation method for constructing an organic-inorganic hybrid structure using the surface of carbon fiber, in which a metal polyphenol network and carbon fiber are coated on the surface of the carbon fiber, and at the same time, the strong adhesion of the metal polyphenol network and the π-π conjugation of carbon nanotubes are used to quickly and orderly self-assemble the "organic-inorganic" hybrid structure on the surface of the carbon fiber, forming oxygen-containing functional groups that can react with the polymer matrix, thereby achieving the strong interfacial interaction required in carbon fiber reinforced epoxy resin (composite material), and significantly improving the interlaminar shear strength and bending strength of the metal polyphenol network and carbon nanotube-coated carbon fiber reinforced epoxy resin. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a morphology diagram of the desized carbon fiber obtained in Example 1;

[0030] Figure 2 The morphology of the metal polyphenol network and carbon nanotube-coated carbon fiber obtained in Example 1;

[0031] Figure 3 This is a scanning electron microscope image of the fracture surface of the desized carbon fiber reinforced composite material obtained in Example 2;

[0032] Figure 4 This is a scanning electron microscope image of the fracture surface of the metal polyphenol network and carbon nanotube-coated carbon fiber reinforced composite material obtained in Example 2. DETAILED DESCRIPTION

[0033] In order to better understand the present invention, the technical solutions of the present invention are described in detail below with specific examples, but the present invention is not limited thereto.

[0034] Other raw materials used in the present invention are all commercially available products.

[0035] Example 1

[0036] The carbon fiber was placed in a Soxhlet extractor, acetone was added, the temperature was raised to 68°C, and the reaction was carried out for 48 hours to remove the sizing agent on the surface of the carbon fiber. After the reaction was completed, the carbon fiber was taken out, washed with deionized water 5 times, and dried to obtain the desized carbon fiber;

[0037] 4.25 g of tannic acid and 2.03 g of FeCl3·6H2O powder were dissolved in 200 ml of deionized water and stirred with a magnetic stirrer for 10 min (stirring rate was 1000 r / min) to obtain TA and Fe 3+ Metal polyphenol network (MPN) solution with a molar ratio of 1:3;

[0038] 0.1 g of carbon nanotubes were dissolved in 200 ml of deionized water and ultrasonicated at 100 kHz for 30 min to obtain a carbon nanotube (CNTs) suspension;

[0039] 10 g of desized carbon fiber was first placed in an MPN solution and ultrasonically immersed for 10 minutes (the frequency of ultrasonic oscillation was 100 kHz), then rinsed with deionized water three times, and then the desized carbon fiber was placed in a CNTs suspension and ultrasonically immersed for 10 minutes (the frequency of ultrasonic oscillation was 100 kHz), and then rinsed with deionized water three times again until the supernatant was colorless and transparent. The carbon fiber was then placed in an electric blast drying oven and dried at 60°C for 6 hours to obtain a metal polyphenol network and carbon nanotube-coated carbon fiber.

[0040] The morphology of the desized carbon fiber obtained in Example 1 is as follows: Figure 1 The morphology of metal polyphenol network and carbon nanotube coated carbon fiber is shown in Figure 2 shown.

[0041] The desized carbon fibers, MPN-coated carbon fibers, and CNTs-coated carbon fibers obtained in Example 1 were respectively compounded with epoxy resin E51 and molded using a plate vulcanizer to produce composite materials (the desized carbon fibers, MPN-coated carbon fibers, and CNTs-coated carbon fibers each accounted for 63% of the composite volume fraction). The interlaminar shear strength (ILSS) and flexural strength of the composite materials were tested. The composite materials were prepared by fully impregnating the desized carbon fibers, MPN-coated carbon fibers, and CNTs-coated carbon fibers in epoxy resin E51 to obtain two types of resin-impregnated carbon fibers. The temperature of the plate vulcanizer was adjusted to 90°C using a temperature control system. While the platen was heated to the specified temperature, a mold wrapped with the resin-impregnated carbon fibers was placed in the plate vulcanizer for preheating. When the platen temperature reached the specified temperature, the pressure was adjusted to 5 MPa using a pressure control system. The molding system was started and maintained at 90°C and 5 MPa for 1 hour. The temperature was then adjusted to 120°C and the pressure to 10 MPa for 2 hours. Finally, the temperature was adjusted to 150°C and the pressure was still at 10 MPa for 3 hours. After the molding is completed, the heating system is turned off, and the sample is naturally cooled to room temperature under the pressure-maintaining state, and then demoulded to obtain a composite material sample strip.

[0042] The desized carbon fiber reinforced epoxy resin composite material of this example had an interlaminar shear strength and flexural strength of 50.9 MPa and 808.42 MPa, respectively. The MPN- and CNTs-coated carbon fiber reinforced epoxy resin composite material had an interlaminar shear strength and flexural strength of 74.25 MPa and 1211.82 MPa, respectively. The carbon fibers treated with MPNs and CNTs showed a tighter chemical bond with the resin as the number of surface oxygen-containing groups increased, improving the composite material's interfacial properties and increasing both interlaminar shear strength and flexural strength.

[0043] Example 2

[0044] The carbon fiber was placed in a Soxhlet extractor, acetone was added, the temperature was raised to 68°C, and the reaction was carried out for 48 hours to remove the sizing agent on the surface of the carbon fiber. After the reaction was completed, the carbon fiber was taken out, washed with deionized water 5 times, and dried to obtain the desized carbon fiber;

[0045] 4.25 g of tannic acid and 2.03 g of FeCl3·6H2O powder were dissolved in 200 ml of deionized water and stirred with a magnetic stirrer for 10 min (stirring rate was 1000 r / min) to obtain TA and Fe 3+ Metal polyphenol network (MPN) solution with a molar ratio of 1:3;

[0046] 0.1 g of carbon nanotubes were dissolved in 200 ml of deionized water and ultrasonicated at 100 kHz for 30 min to obtain a carbon nanotube (CNTs) suspension;

[0047] 10g of desized carbon fiber was first placed in an MPN solution for ultrasonic immersion for 10 minutes (the frequency of ultrasonic oscillation was 100kHz), and then rinsed with deionized water three times. The desized carbon fiber was then placed in a CNTs suspension for ultrasonic immersion for 10 minutes (the frequency of ultrasonic oscillation was 100kHz), and rinsed with deionized water three times again; it was placed in the above MPN solution for ultrasonic immersion for 10 minutes, taken out and rinsed with deionized water three times, and then placed in a CNTs suspension for ultrasonic immersion for 10 minutes, taken out and rinsed with deionized water until the supernatant was colorless and transparent, and then the carbon fiber was placed in an electric blast drying oven and dried at 60°C for 6 hours to obtain a metal polyphenol network and carbon nanotube-coated carbon fiber.

[0048] The scanning electron microscope image of the fracture surface of the desizing carbon fiber reinforced composite material obtained in Example 2 is as follows: Figure 2 As shown; Figure 3 This is a scanning electron microscope image of the fracture surface of the metal polyphenol network and carbon nanotube-coated carbon fiber reinforced composite material obtained in Example 2.

[0049] The desized carbon fibers, MPN-coated carbon fibers, and CNT-coated carbon fibers obtained in Example 2 were respectively compounded with epoxy resin E51 and molded using a plate vulcanizer to produce composite materials (the desized carbon fibers, metal polyphenol network-coated carbon fibers, and carbon nanotube-coated carbon fibers each accounted for 63% of the composite volume fraction). The interlaminar shear strength (ILSS) and flexural strength of the composite materials were tested. The composite materials were prepared by fully impregnating the desized carbon fibers, metal polyphenol network-coated carbon fibers, and carbon nanotube-coated carbon fibers in epoxy resin E51 to produce two resin-impregnated carbon fibers. The temperature of the plate vulcanizer was maintained at 90°C using a temperature control system. While the platen was heated to the specified temperature, a mold wrapped with the resin-impregnated carbon fibers was placed in the plate vulcanizer for preheating. Once the platen temperature reached the specified temperature, the pressure was adjusted to 5 MPa using a pressure control system. The molding system was activated and maintained at 90°C and 5 MPa for 1 hour. The temperature was then adjusted to 120°C and the pressure to 10 MPa for 2 hours. Finally, the temperature was adjusted to 150°C and the pressure was maintained at 10 MPa for 3 hours. After the molding is completed, the heating system is turned off, and the sample is naturally cooled to room temperature under the pressure-maintaining state, and then demoulded to obtain a composite material sample strip.

[0050] The interlaminar shear strength and flexural strength of the MPN and CNTs coated carbon fiber reinforced epoxy resin-based composite material of this embodiment are 72.7 MPa and 929.57 MPa, respectively.

[0051] Example 3

[0052] The carbon fiber was placed in a Soxhlet extractor, acetone was added, the temperature was raised to 68°C, and the reaction was carried out for 48 hours to remove the sizing agent on the surface of the carbon fiber. After the reaction was completed, the carbon fiber was taken out, washed with deionized water 5 times, and dried to obtain the desized carbon fiber;

[0053] 4.25 g of tannic acid and 2.03 g of FeCl3·6H2O powder were dissolved in 200 ml of deionized water and stirred with a magnetic stirrer for 10 min (stirring rate was 1000 r / min) to obtain TA and Fe 3+ Metal polyphenol network (MPN) solution with a molar ratio of 1:3;

[0054] 0.1 g of carbon nanotubes were dissolved in 200 ml of deionized water and ultrasonicated at 100 kHz for 30 min to obtain a carbon nanotube (CNTs) suspension;

[0055] The MPN solution and CNTs suspension were mixed and sonicated for 30 min;

[0056] 10 g of desized carbon fiber was placed in a mixed solution of MPN and CNTs and ultrasonically immersed for 10 minutes (the frequency of ultrasonic oscillation was 100 kHz), then rinsed with deionized water three times, taken out and rinsed with deionized water until the supernatant was colorless and transparent, and then the carbon fiber was placed in an electric blast drying oven and dried at 60°C for 6 hours to obtain a metal polyphenol network and carbon nanotube-coated carbon fiber.

[0057] The interlaminar shear strength and flexural strength of the MPN and CNTs coated carbon fiber reinforced epoxy resin-based composite material of this embodiment are 70.31 MPa and 1087.61 MPa, respectively.

[0058] It can be seen from Examples 1-3 that the different numbers of assembled layers and methods of the metal polyphenol network and carbon nanotubes will greatly change the structure and morphology of the carbon fiber surface, affecting its performance (interlaminar shear strength and bending strength).

[0059] Example 4

[0060] The carbon fiber was placed in a Soxhlet extractor, acetone was added, the temperature was raised to 68°C, and the reaction was carried out for 48 hours to remove the sizing agent on the surface of the carbon fiber. After the reaction was completed, the carbon fiber was taken out, washed with deionized water 5 times, and dried to obtain the desized carbon fiber;

[0061] 4.25 g of tannic acid and 2.03 g of FeCl3·6H2O powder were dissolved in 200 ml of deionized water and stirred with a magnetic stirrer for 10 min (stirring rate was 1000 r / min) to obtain TA and Fe 3+ Metal polyphenol network (MPN) solution with a molar ratio of 1:3;

[0062] 10 g of desized carbon fiber was first placed in the MPN solution for ultrasonic immersion for 10 minutes (the frequency of ultrasonic oscillation was 100 kHz), then rinsed with deionized water three times until the supernatant was colorless and transparent, and then the carbon fiber was placed in an electric blast drying oven and dried at 60°C for 6 hours to obtain metal polyphenol network-coated carbon fiber.

[0063] The MPN-coated carbon fibers obtained in Example 4 were compounded with epoxy resin E51 and molded using a flat-plate vulcanizer to produce a composite material (the MPN-coated carbon fibers comprised 63% of the composite material by volume). The interlaminar shear strength (ILSS) and flexural strength of the composite material were tested. The specific process was the same as in Example 1.

[0064] The interlaminar shear strength and flexural strength of the MPN-coated carbon fiber reinforced epoxy resin-based composite material of this embodiment are 61.23 MPa and 927.59 MPa, respectively.

[0065] Example 5

[0066] The carbon fiber was placed in a Soxhlet extractor, acetone was added, the temperature was raised to 68°C, and the reaction was carried out for 48 hours to remove the sizing agent on the surface of the carbon fiber. After the reaction was completed, the carbon fiber was taken out, washed with deionized water 5 times, and dried to obtain the desized carbon fiber;

[0067] 0.1 g of carbon nanotubes were dissolved in 200 ml of deionized water and ultrasonicated at 100 kHz for 30 min to obtain a carbon nanotube (CNTs) suspension;

[0068] 10 g of desized carbon fiber was placed in a CNTs suspension and ultrasonically immersed for 10 min (the frequency of ultrasonic oscillation was 100 kHz), and then rinsed with deionized water three times until the supernatant was colorless and transparent. The carbon fiber was then placed in an electric heated blast drying oven and dried at 60°C for 6 h to obtain carbon nanotube-coated carbon fiber.

[0069] The CNTs-coated carbon fibers obtained in Example 5 were compounded with epoxy resin E51 and molded using a flat vulcanizer to produce a composite material (the CNTs-coated carbon fibers comprised 63% of the composite material by volume). The interlaminar shear strength (ILSS) and flexural strength of the composite material were tested. The specific process was the same as in Example 1.

[0070] The interlaminar shear strength and flexural strength of the CNTs-coated carbon fiber reinforced epoxy resin-based composite material of this embodiment are 63.55 MPa and 895.49 MPa, respectively.

[0071] It can be seen from Examples 1, 4, and 5 that the performance of the simple MPN-coated carbon fiber reinforced epoxy resin-based composites and the CNTs-coated carbon fiber reinforced epoxy resin-based composites are improved compared with the desized carbon fiber reinforced epoxy resin-based composites, but are both lower than the MPN- and CNTs-coated carbon fiber reinforced epoxy resin-based composites.

[0072] Example 6

[0073] The difference from Example 1 is that 0.05 g of carbon nanotubes were dissolved in 200 ml of deionized water, and ultrasonicated at 100 kHz for 30 min to obtain a carbon nanotube (CNTs) suspension. The rest of the process was the same.

[0074] Example 7

[0075] The difference from Example 1 is that 0.15 g of carbon nanotubes were dissolved in 200 ml of deionized water, and ultrasonicated at 100 kHz for 30 min to obtain a carbon nanotube (CNTs) suspension. The rest of the steps were the same.

[0076] Example 8

[0077] The difference from Example 1 is that 0.25 g of carbon nanotubes were dissolved in 200 ml of deionized water, and ultrasonicated at 100 kHz for 30 min to obtain a carbon nanotube (CNTs) suspension. The rest of the steps were the same.

[0078] By comparison, it is found that the interlaminar shear strength and flexural strength of Examples 6 and 7 are improved compared with the simple desizing carbon fiber reinforced epoxy resin-based composite material, but are lower than Example 1. At the same time, the performance of Example 8 is lower than that of Examples 6 and 7.

[0079] Tannic acid provides reactive functional groups, promoting the dispersion and uniform adhesion of CNTs to the carbon fiber surface. Modification with tannic acid improves the surface wettability of the carbon fibers, thereby aiding CNT adhesion. The combination of the two contributes to a more stable and uniform composite structure. Tannic acid acts as a surface modifier, increasing the hydrophilicity of the carbon fibers and promoting uniform dispersion of CNTs. Furthermore, the inclusion of CNTs increases the mechanical strength and electrical conductivity of the composite, compensating for any potential strength loss caused by the tannic acid.

[0080] Example 9

[0081] The carbon fiber was placed in a Soxhlet extractor, acetone was added, the temperature was raised to 60°C, and the reaction was carried out for 36 hours to remove the sizing agent on the surface of the carbon fiber. After the reaction was completed, the carbon fiber was taken out, washed with deionized water 5 times, and dried to obtain the desized carbon fiber;

[0082] 4.25 g of tannic acid and 0.677 g of FeCl3·6H2O powder were dissolved in 200 ml of deionized water and stirred with a magnetic stirrer for 5 min (stirring rate was 900 r / min) to obtain TA and Fe 3+ a metal polyphenol network (MPN) solution with a molar ratio of 1:1;

[0083] 0.1 g of carbon nanotubes were dissolved in 200 ml of deionized water and ultrasonicated at 80 kHz for 5 min to obtain a carbon nanotube (CNTs) suspension;

[0084] 10g of desized carbon fiber was first placed in MPN solution and ultrasonically immersed for 5 minutes (the frequency of ultrasonic oscillation was 80kHz), then rinsed with deionized water 3 times, and then the desized carbon fiber was placed in CNTs suspension and ultrasonically immersed for 5 minutes (the frequency of ultrasonic oscillation was 80kHz), and rinsed with deionized water again 3 times until the supernatant was colorless and transparent, and then the carbon fiber was placed in an electric blast drying oven and dried at 50°C for 5 hours to obtain a metal polyphenol network and carbon nanotube-coated carbon fiber.

[0085] The interlaminar shear strength and flexural strength of the MPN and CNTs coated carbon fiber reinforced epoxy resin-based composite materials obtained in this example are 71.99 MPa and 1190.23 MPa, respectively.

[0086] Example 10

[0087] The carbon fiber was placed in a Soxhlet extractor, acetone was added, the temperature was raised to 80°C, and the reaction was carried out for 72 hours to remove the sizing agent on the surface of the carbon fiber. After the reaction was completed, the carbon fiber was taken out, washed with deionized water 5 times, and dried to obtain the desized carbon fiber;

[0088] 4.25g of tannic acid and 1.35g of FeCl3·6H2O powder were dissolved in 200ml of deionized water and stirred with a magnetic stirrer for 15min (stirring mixing speed was 1200r / min) to obtain TA and Fe 3+ Metal polyphenol network (MPN) solution with a molar ratio of 1:2;

[0089] 0.1 g of carbon nanotubes were dissolved in 200 ml of deionized water and ultrasonicated at 120 kHz for 30 min to obtain a carbon nanotube (CNTs) suspension.

[0090] 10g of desized carbon fiber was first placed in MPN solution and ultrasonically immersed for 20 minutes (the frequency of ultrasonic oscillation was 120kHz), then rinsed with deionized water three times, and then the desized carbon fiber was placed in CNTs suspension and ultrasonically immersed for 20 minutes (the frequency of ultrasonic oscillation was 120kHz), and rinsed with deionized water again three times until the supernatant was colorless and transparent, and then the carbon fiber was placed in an electric blast drying oven and dried at 70°C for 7 hours to obtain a metal polyphenol network and carbon nanotube-coated carbon fiber.

[0091] The interlaminar shear strength and flexural strength of the MPN and CNTs coated carbon fiber reinforced epoxy resin-based composite materials obtained in this example are 72.28 MPa and 1179.79 MPa, respectively.

[0092] The raw materials listed in the present invention, as well as the upper and lower limits and interval values ​​of the raw materials, and the upper and lower limits and interval values ​​of the process parameters can all realize the present invention, and the embodiments are not listed one by one here.

[0093] The above description is only a preferred embodiment of the present invention, which certainly cannot be used to limit the scope of rights of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and changes can be made without departing from the principles of the present invention. These improvements and changes are also considered to be within the scope of protection of the present invention.

Claims

1. A method for constructing an organic-inorganic hybrid structure using the surface of carbon fiber, characterized in that: The preparation method comprises the following steps: Step 1: Desizing the carbon fiber in acetone to obtain desizing carbon fiber; Step 2: dissolving tannic acid and FeCl3·6H2O in deionized water, stirring and mixing to obtain a metal polyphenol network solution, i.e., an MPN solution; wherein the molar ratio of tannic acid to FeCl3·6H2O is 1:1 to 3; Step 3: dissolving carbon nanotubes in deionized water and ultrasonically obtaining a carbon nanotube suspension, i.e., a CNTs suspension; Step 4: The desized carbon fiber is first placed in the MPN solution for ultrasonic impregnation, rinsed, and then the MPN-coated carbon fiber is placed in the CNTs suspension for ultrasonic impregnation, rinsed again, and the above operation is repeated until the supernatant is colorless and transparent, and then dried to obtain a metal polyphenol network and carbon nanotube-coated carbon fiber; The mass ratio of the tannic acid to the carbon nanotubes is 4.25:0.05-0.

15.

2. The method for constructing an organic-inorganic hybrid structure using a carbon fiber surface according to claim 1, characterized in that: In the step 1, the acetone desizing temperature is 60° C. to 80° C., and the desizing time is 36 to 72 hours.

3. The method for constructing an organic-inorganic hybrid structure using a carbon fiber surface according to claim 1, wherein: In the step 2, the mass volume ratio of tannic acid to deionized water (g:ml) is 4.25:200; the mixture is stirred and mixed with a magnetic stirrer for 5-15 minutes at a stirring rate of 900-1200 r / min; the tannic acid and Fe in the obtained MPN solution are 3+ The molar ratio is 1:1~3.

4. The method for constructing an organic-inorganic hybrid structure using a carbon fiber surface according to claim 1, wherein: In step 3, the ultrasonic frequency is 80 to 120 kHz, and the ultrasonic time is 5 to 30 minutes.

5. The method for constructing an organic-inorganic hybrid structure using a carbon fiber surface according to claim 1, wherein: In step 4, the ultrasonic frequency is 80-120 kHz; the ultrasonic immersion is 5-20 min, the drying temperature is 50-70° C.; the drying time is 5-7 h; and the number of immersion cycles is 1-3 times.

6. The method for constructing an organic-inorganic hybrid structure using a carbon fiber surface according to claim 1, wherein: The mass ratio of the MPN solution to the CNTs suspension in step 4 is 1-2:1-2; the mass ratio of the desized carbon fiber to the tannic acid in step 2 is 10:4.

25.

7. The method for constructing an organic-inorganic hybrid structure using the carbon fiber surface according to claim 1, characterized in that: The following steps are involved: Step 1: Place the carbon fiber in a Soxhlet extractor, add acetone, heat to 68°C, react for 48 hours, take out after the reaction is completed, wash with deionized water, and dry to obtain desized carbon fiber; Step 2: Dissolve 4.25g of tannic acid and 2.03g of FeCl3·6H2O powder in 200ml of deionized water, stir and mix with a magnetic stirrer for 10min at a stirring rate of 1000r / min to obtain TA and Fe 3+ a metal polyphenol network solution with a molar ratio of 1:3; Step 3: Dissolve 0.1 g of carbon nanotubes in 200 ml of deionized water and ultrasonicate at 100 kHz for 30 min to obtain a carbon nanotube suspension; Step 4: Place 10g of desized carbon fiber in the MPN solution and ultrasonically immerse it for 10 minutes, then rinse it with deionized water three times, then place the MPN-coated carbon fiber in the CNTs suspension and ultrasonically immerse it for 10 minutes, and rinse it with deionized water three times again until the supernatant is colorless and transparent, then place it in a drying oven and dry it at 60°C for 6 hours to obtain a metal polyphenol network and carbon nanotube-coated carbon fiber.

8. The metal polyphenol network and carbon nanotube-coated carbon fiber obtained according to the preparation method of any one of claims 1 to 7.

9. The use of the metal polyphenol network and carbon nanotube-coated carbon fiber in a composite material according to claim 8, characterized in that: The metal polyphenol network and carbon nanotube-coated carbon fiber are compounded with epoxy resin and a composite material is prepared through a molding process.

10. The use of the metal polyphenol network and carbon nanotube-coated carbon fiber in a composite material according to claim 9, characterized in that: The metal polyphenol network and the carbon nanotube-coated carbon fiber account for 63% of the volume fraction of the composite material; the metal polyphenol network and the carbon nanotube-coated carbon fiber are fully impregnated in epoxy resin E51, the temperature of the vulcanizer is adjusted to 90°C, and the mold wrapped with the resin-impregnated metal polyphenol network and the carbon nanotube-coated carbon fiber is placed in the vulcanizer for preheating, and then the pressure is adjusted to 5MPa through the pressure control system, and the molding system is started and maintained at 90°C and 5MPa for 1 hour; then the temperature is adjusted to 120°C and the pressure is 10MPa, and maintained for 2 hours; finally, the temperature is adjusted to 150°C and the pressure is 10MPa, and maintained for 3 hours; after the molding is completed, it is naturally cooled to room temperature in the pressure-maintaining state, and demolded to obtain a composite material.

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