Preparation method and application of asphalt-based reinforced carbon fiber composite material based on metal organic framework interface

Abstract

The invention relates to a preparation method and application of an asphalt-based reinforced carbon fiber composite material based on a metal organic framework interface, and the preparation method comprises the following steps: 1) taking melt spinning asphalt fibers as a carbon fiber matrix, and realizing surface lossless functionalization of a polycyclic aromatic hydrocarbon-containing organic ligand through a pi-pi conjugation effect; 2) taking an organic ligand group introduced on the surface of the non-destructively modified fiber as an MOFs nucleation site, and reacting with transition metal ions to synthesize an MOFs crystal; 3) further inducing secondary growth of MOFs on the fiber surface to form a crystal film; and 4) carbonizing in an inert atmosphere to obtain the integrated composite fiber. The method has the advantages that specific polycyclic aromatic hydrocarbon and asphalt fibers are introduced to form a stable composite structure, and nondestructive functionalization of the surfaces of the fibers is achieved. An integrated preparation thought of synchronous conversion of carbon fibers and a surface metal layer is adopted, a uniformly-dispersed and compact metal atomic layer is obtained through confinement in-situ decomposition, and an effective synthesis approach is provided for controllable preparation of the high-interface-strength metal atomic layer on the surface of the carbon fibers.

Description

Technical Field

[0001] This invention belongs to the technical field of carbon fiber reinforced aluminum alloy composite materials, and particularly relates to a method for preparing pitch-based reinforced carbon fiber composite materials based on metal-organic framework interfaces and their applications. Background Technology

[0002] Aluminum alloys are high-quality lightweight engineering materials, widely used in aerospace, automotive, and electronics industries due to their light weight, high strength, and good weldability. With rapid economic and social development and the continuous improvement of transportation and communication infrastructure, the performance requirements for aluminum-based composite materials are facing higher challenges in order to meet the demands for a more intelligent, convenient, and efficient lifestyle. Therefore, the design and development of novel lightweight and high-strength aluminum-based composite materials is an urgent problem to be solved.

[0003] Carbon fiber is a novel material with excellent comprehensive properties. Due to its lightweight, high strength, and low density, carbon fiber reinforced aluminum matrix composites formed with aluminum alloys have broad application prospects in many fields such as aerospace, automotive, and electronics. However, the interface problem between carbon fiber and the aluminum alloy matrix limits the rapid development of composite materials. Poor wettability between carbon fiber and aluminum alloy results in weak interfacial bonding strength. Furthermore, carbon fiber is prone to strong interfacial reactions with molten aluminum, generating brittle Al4C3 products, which reduces the load-bearing capacity of the composite material.

[0004] One of the main effective means to solve the aforementioned interface problems at present is to coat the carbon fiber surface with a metal coating. Based on this synthesis approach, the interface problem between carbon fiber and aluminum alloy has been significantly improved. For example, patent application number CN202311135403.2 discloses a method for forming and integrating carbon fiber reinforced aluminum alloy sandwich tubes, in which metallic nickel is electrodeposited on the carbon fiber surface, and the nickel layer undergoes a diffusion metallurgical composite reaction with the aluminum alloy. However, a key problem facing the coating structure is that the interfacial bonding force between the metal coating and the carbon fiber is relatively weak. During high-temperature and high-pressure preparation or use in harsh environments, the difference in thermal expansion coefficients can easily lead to structural collapse or surface peeling. For example, patent application number CN202411529972.X discloses a layered metal-organic framework modified carbon fiber, its preparation method, and its application. The carbon fiber is first oxidized, and then a layered metal-organic framework is prepared on the surface of the oxidized carbon fiber, which improves the wettability with epoxy resin and ensures that the organic structure is not prone to collapse. This use of a metal-organic framework as a novel interfacial connector between the fiber and the matrix is ​​a highly efficient and high-strength interface synthesis approach. However, to ensure interfacial bonding strength and reduce voids and cracks at the interface, carbon fibers typically undergo functionalization treatments such as surface oxidation, chemical grafting, and sizing agent modification to increase surface chemical activity and roughness. This process severely damages the intrinsic structure of the carbon fibers, reducing their bulk strength. Therefore, constructing efficient and high-strength interfacial carbon fiber reinforced composite materials with suitable molecular structures and precise interface design is crucial for developing novel lightweight and high-strength carbon fiber reinforced aluminum matrix composites. Summary of the Invention

[0005] To overcome the shortcomings of the prior art, the purpose of this invention is to provide a method for preparing and applying pitch-based reinforced carbon fiber composite materials based on metal-organic framework interfaces. The method uses melt-spun pitch fibers as the carbon fiber matrix, introduces specific functional groups by designing the molecular structure of the organic framework, performs non-destructive surface functionalization treatment on the fibers using the π-π conjugation effect, and then uses secondary growth of metal-organic frameworks and confined synthesis of transition metals by high-temperature pyrolysis in situ reduction to achieve controllable preparation of a high-interfacial-strength metal atomic layer on the carbon fiber surface, thus obtaining an integrated metal atomic layer-coated carbon fiber composite material.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A method for preparing pitch-based reinforced carbon fiber composite materials based on metal-organic framework interfaces includes the following steps:

[0008] 1) Using melt-spun pitch fiber as the carbon fiber matrix, surface functionalization is achieved through the π-π conjugation effect using organic ligands containing polycyclic aromatic hydrocarbons;

[0009] 2) Using the organic ligand groups introduced on the surface of the fiber after non-destructive modification as nucleation sites for MOFs, MOFs crystals are synthesized on the surface of functionalized fibers by reacting with transition metal ions.

[0010] 3) Further induce MOFs to grow on the surface of functionalized fibers to form a crystalline film;

[0011] 4) Carbon fibers with an integrated metal atomic layer coating are obtained by high-temperature carbonization in an inert gas atmosphere.

[0012] The method for preparing pitch-based reinforced carbon fiber composites based on metal-organic framework interfaces specifically includes the following steps:

[0013] 1) Preparation of asphalt fiber substrate: Take a spinnable asphalt sample and place it in a melt spinning tank. Melt spin at 280~400℃ and 0.5~1.5MPa, with a take-up linear speed of 600~1500m / min.

[0014] 2) Surface functionalization treatment of asphalt fiber: Add organic ligands with polycyclic aromatic hydrocarbons to a solvent to prepare a solution with a mass fraction of 1%~10%; immerse the asphalt fiber obtained in step 1) in the solution for 10~30 min, vacuum dry at 60~70℃, and then place it in an air atmosphere for crosslinking stabilization at 150~250℃ for 4~20 h.

[0015] 3) Synthesis of MOFs crystals on the surface of pitch fiber: The fiber obtained in step 2) was immersed in a methanol solution of transition metal salt and reacted solvothermically at 90~130℃ for 1~2h; after the reaction was completed, it was naturally cooled to room temperature and rinsed 2~3 times with methanol and deionized water respectively, and then vacuum dried at 60~70℃.

[0016] 4) Preparation of MOF crystal film on the surface of pitch fiber: A MOF crystal film growth solution is prepared by mixing a transition metal salt methanol solution with an imidazole organic ligand methanol solution and stirring evenly. The fiber obtained in step 3) is immersed in the growth solution and subjected to a solvothermal reaction at 70~120℃ for 2~4h. After the reaction is completed, the fiber is naturally cooled to room temperature and rinsed 2~3 times with methanol and deionized water respectively, and then vacuum dried at 60~70℃.

[0017] 5) Preparation of carbon fiber with integrated metal atomic layer coating: The fiber sample obtained in step 4) is placed in an inert gas atmosphere and carbonized at 800~1200℃ for 2~3h, with a heating rate of 0.5~5℃ / min and an air flow rate of 60~100mL / min.

[0018] The diameter of the pitch fiber substrate is 8~24μm.

[0019] The organic ligand containing a polycyclic aromatic hydrocarbon is one of phenanthreneimidazole, naphthemidazole, or pyreneimidazole organic ligands.

[0020] In step 2), the solvent is one or more of methanol, ethanol, and N,N-dimethylformamide.

[0021] The transition metal is one or more of Ni, Cu, and Mn.

[0022] The imidazole organic ligand is one of 2-methylimidazole, 4-methylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, and benzimidazole.

[0023] The molar concentration of the transition metal salt methanol solution is 0.5~3 mol / L; the molar concentration of the imidazole organic ligand methanol solution is 0.1~3 mol / L.

[0024] An application of a pitch-based reinforced carbon fiber composite material based on a metal-organic framework interface is disclosed, which is used to manufacture a high-efficiency, high-strength interface carbon fiber reinforced aluminum matrix composite plate.

[0025] Compared with the prior art, the beneficial effects of the present invention are:

[0026] 1. This invention uses melt-spun pitch fiber as the carbon fiber matrix. By designing the molecular structure of the organic framework, specific functional groups are introduced. The surface of the fiber is functionalized without damage using the π-π conjugation effect. Then, the high-interfacial-strength metal atomic layer on the carbon fiber surface is controllably prepared by secondary growth of metal-organic framework and in-situ reduction of transition metal by high-temperature pyrolysis. This provides a controllable synthesis route that is easy to achieve excellent engineering structure and comprehensive performance for the development of high-efficiency and high-strength interfacial carbon fiber reinforced composite materials.

[0027] 2. Based on the inherent organic-inorganic hybrid characteristics of MOFs (metal-organic frameworks), this invention uses MOFs as an interfacial connector between fibers and metal matrices. By utilizing the coordination bonding of MOFs, the wetting properties between carbon fibers and aluminum alloy matrices are greatly improved and the formation of the Al4C3 brittle phase is prevented. This achieves a dual interfacial bonding mechanism of mechanical interlocking and chemical bonding between carbon fibers and the matrix, thereby improving the interfacial bonding strength of carbon fiber reinforced aluminum matrix composites.

[0028] 3. Based on the unique macromolecular structure of asphaltene, this invention introduces a specific polycyclic aromatic hydrocarbon structure into the organic ligand. By utilizing the π-π stacking effect, a stable composite structure with asphalt fibers is formed in a specific arrangement, which improves the chemical activity of the fiber interface, enhances the interfacial bonding ability, and ensures that the subsequent MOF crystals are tightly wrapped on the fiber surface without destroying the intrinsic structure and bulk strength of the fiber.

[0029] 4. Based on the characteristics of organic ligand groups and metal ions coordinating and self-assembling during the crystallization process of MOFs, the coordinate bonds introduced on the fiber surface after non-destructive modification are the dominant forces between ligand molecules and metal ions, providing nucleation sites for the formation of MOFs, overcoming the nucleation bottleneck in the crystal film formation process, promoting the anchoring of MOFs on the fiber surface, and further inducing the secondary growth of MOFs on the fiber surface to form a dense crystal film, improving the pore, dislocation and step structure of the fiber surface, and enhancing the buffering capacity of the connector to release internal and external stresses.

[0030] 5. This invention is based on the principle of in-situ reduction of metal ions during the high-temperature pyrolysis of MOFs. It adopts an integrated preparation approach that simultaneously transforms carbon fibers and surface metal layers. That is, carbon fibers and metal atomic layers are formed simultaneously during carbonization. The strong anchoring force between the metal components and the carbon fiber carrier is ensured by chemical bonding. The number and high dispersion of high-density metal atoms on the fiber surface are ensured by confined in-situ decomposition reaction. The structure of metal centers and nitrogen-rich ligands is adjusted at the atomic scale to avoid agglomeration caused by the free energy of the metal surface and improve the effective utilization rate of functional groups. This provides an effective synthetic route for the controllable preparation of high interfacial strength metal atomic layers on the surface of carbon fibers. Attached Figure Description

[0031] Figure 1 This is a SEM image of an integrated manganese-copper bimetallic atomic layer coated pitch-based reinforced carbon fiber composite material.

[0032] Figure 2 This is a SEM image of an integrated multi-metal atomic layer coated pitch-based reinforced carbon fiber composite material.

[0033] Figure 3 This is the SEM image of Comparative Example 1.

[0034] Figure 4 This is the SEM image of Comparative Example 2. Detailed Implementation

[0035] The present invention will now be described in detail with reference to the accompanying drawings, but it should be noted that the implementation of the present invention is not limited to the following embodiments.

[0036] A method for preparing pitch-based reinforced carbon fiber composites based on metal-organic framework interfaces involves using melt-spun pitch fibers as the carbon fiber matrix. The fiber surface is non-destructively functionalized using organic ligands containing polycyclic aromatic hydrocarbons (PAHs) to provide nucleation sites for the metal-organic framework. This further induces the secondary growth of the metal-organic framework on the fiber surface to form a crystalline film. Finally, high-temperature carbonization under an inert gas atmosphere yields carbon fibers with an integrated metal atomic layer coating. The specific steps include:

[0037] 1) Preparation of asphalt fiber substrate: Take a spinnable asphalt sample and place it in a melt spinning tank. Melt spin at 280~400℃ and 0.5~1.5MPa, with a take-up linear speed of 600~1500m / min. The diameter of the obtained asphalt fiber substrate is 8~24μm.

[0038] 2) Surface functionalization treatment of asphalt fibers: An organic ligand containing a polycyclic aromatic hydrocarbon is added to a solvent to prepare a solution with a mass fraction of 1%~10%; the asphalt fibers obtained in step 1) are immersed in the solution for 10~30 min, vacuum dried at 60~70℃, and then crosslinked and stabilized at 150~250℃ for 4~20 h under an air atmosphere; the organic ligand containing the polycyclic aromatic hydrocarbon is one of phenanthreneimidazole, naphthiimidazole, or pyreneimidazole organic ligands. The solvent is one or more of methanol, ethanol, and N,N-dimethylformamide.

[0039] 3) Synthesis of MOFs crystals on the surface of pitch fiber: The fiber obtained in step 2) was immersed in a methanol solution of transition metal salt and reacted solvothermically at 90~130℃ for 1~2h; after the reaction was completed, it was naturally cooled to room temperature and rinsed 2~3 times with methanol and deionized water respectively, and then vacuum dried at 60~70℃.

[0040] 4) Preparation of MOFs crystal film on the surface of asphalt fiber: A MOFs crystal film growth solution is prepared by mixing a transition metal salt methanol solution with an imidazole organic ligand methanol solution and stirring until homogeneous. The fiber obtained in step 3) is immersed in the growth solution and subjected to a solvothermal reaction at 70-120℃ for 2-4 hours. After the reaction, it is naturally cooled to room temperature and rinsed 2-3 times with methanol and deionized water, respectively, and then vacuum dried at 60-70℃. The transition metal is one or more of Ni, Cu, and Mn. The transition metal salt is one of nitrate, acetate, or acetylacetone salt. The imidazole organic ligand is one of 2-methylimidazolium, 4-methylimidazolium, 1,2-dimethylimidazolium, 2-ethyl-4-methylimidazolium, or benzimidazole. The molar concentration of the transition metal salt methanol solution is 0.5-3 mol / L; the molar concentration of the imidazole organic ligand methanol solution is 0.1-3 mol / L.

[0041] 5) Preparation of carbon fiber with integrated metal atomic layer coating: The fiber sample obtained in step 4) is placed in an inert gas atmosphere and carbonized at 800~1200℃ for 2~3h, with a heating rate of 0.5~5℃ / min and a gas flow rate of 60~100mL / min. The inert gas atmosphere is nitrogen or argon.

[0042] The carbon fibers with a dense metal atomic layer on their surface obtained by the above preparation method can be used to manufacture high-efficiency, high-strength interfacial carbon fiber reinforced aluminum matrix composites.

[0043] Example 1:

[0044] Preparation of high-strength interfacial integrated nickel metal atomic layer coated pitch-based reinforced carbon fiber composite material (Cf@Ni) and its application in the manufacture of composite carbon fiber reinforced aluminum matrix composite plate (Cf@Ni-Al):

[0045] 1) Take 100g of coal tar pitch sample and place it in a melt spinning tank. Melt spinning is carried out at 300℃ and 1MPa to obtain pitch fiber.

[0046] 2) The pitch fiber was impregnated in a 3% (w / w) 1H-phenanthroline[9,10-d]imidazolium ethanol solution, removed after 20 min and vacuum dried at 60℃ for 3 h, and then placed in a forced-air drying oven for crosslinking at 180℃ for 20 h.

[0047] 3) The fiber obtained in step 2) was placed in a 2 mol / L nickel nitrate methanol solution and subjected to a solvothermal reaction at 110 °C for 2 h. After the reaction was completed, it was naturally cooled to room temperature and rinsed three times with methanol and deionized water, respectively, and then dried under vacuum at 60 °C.

[0048] 4) Prepare a 1.2 mol / L nickel nitrate methanol solution and slowly add it dropwise to a 1.2 mol / L 2-methylimidazolium methanol solution. After vigorous stirring, a crystal film growth solution is obtained. The fiber obtained in step 3) is immersed in the crystal film growth solution and subjected to a solvothermal reaction at 120℃ for 2 hours. After the reaction is completed, it is naturally cooled to room temperature and rinsed three times with methanol and deionized water, respectively. Then, it is vacuum dried at 60℃.

[0049] 5) Place the fiber sample obtained in step 4) in a N2 atmosphere with an airflow rate of 60 mL / min, heat it to 800℃ at a heating rate of 1.5℃ / min, and hold it for 3 hours to obtain Cf@Ni composite fiber.

[0050] Cf@Ni composite fiber properties: Ni metal atoms are uniformly and densely wrapped on the surface of carbon fiber. The average fiber diameter is 12μm, the thickness of the Ni metal atom layer on the surface is about 0.8μm, the elastic modulus is 134GPa, and the tensile strength is 870MPa.

[0051] Application of Cf@Ni-Al composite fiber reinforced aluminum alloy plate: Cf@Ni is cut into short fibers with a length of 1±0.2mm and thoroughly mixed with aluminum alloy powder. The mixture is placed in a ball mill jar with anhydrous ethanol as the mixing medium, a ball-to-powder ratio of 10:1, and milled for 0.5 hours. After mixing, the material is placed in a hot press mold and then placed in a vacuum carbon tube hot press furnace. The hot pressing temperature is 600℃, the hot pressing pressure is 35MPa, and the hot pressing time is 1 hour, thus obtaining Cf@Ni-Al, which yields a high-efficiency, high-strength interfacial carbon fiber reinforced aluminum matrix composite plate. In the Cf@Ni-Al composite plate, the composite carbon fiber and aluminum matrix have a good interfacial bond, and no interfacial reaction was observed. Compared with the pure carbon fiber reinforced aluminum alloy plate Cf-Al, its tensile strength is 40±3MPa, while the average tensile strength of the Cf@Ni-Al composite plate is increased by 25.3%.

[0052] Example 2:

[0053] Preparation of high-strength interfacial integrated manganese-copper bimetallic atomic layer coated pitch-based reinforced carbon fiber composite material (Cf@MnCu) and its application in the manufacture of composite carbon fiber reinforced aluminum matrix composite plate (Cf@MnCu-Al):

[0054] 1) Take 100g of coal tar pitch sample and place it in a melt spinning tank. Melt spinning is carried out at 300℃ and 1MPa to obtain pitch fiber.

[0055] 2) The pitch fiber was impregnated in a 4% (w / w) 1H-phenanthroline[9,10-d]imidazolium ethanol solution, removed after 20 min and vacuum dried at 60℃ for 3 h, and then placed in a forced-air drying oven for crosslinking at 200℃ for 12 h.

[0056] 3) The fiber obtained in step 2) was placed in a 1.5 mol / L manganese nitrate methanol solution and subjected to a solvothermal reaction at 120 °C for 2 h. After the reaction was completed, it was naturally cooled to room temperature and washed three times with methanol and deionized water respectively, and then vacuum dried at 60 °C.

[0057] 4) Prepare a 2.5 mol / L nitrate methanol solution with a copper to manganese molar ratio of 1:1. Slowly add the solution dropwise to a 2 mol / L 2-ethyl-4-methylimidazolium methanol solution and stir vigorously to obtain a crystal film growth solution. Immerse the fiber obtained in step 3) in the crystal film growth solution and carry out a solvothermal reaction at 120℃ for 2 hours. After the reaction is completed, allow it to cool naturally to room temperature and rinse it three times with methanol and deionized water, respectively. Then, dry it under vacuum at 60℃.

[0058] 5) Place the fiber sample obtained in step 4) in an N2 atmosphere with an airflow rate of 80 mL / min, heat it to 1000℃ at a heating rate of 0.5℃ / min, and hold it for 3 hours to obtain Cf@MnCu composite fiber.

[0059] Cf@MnCu composite fiber properties: Metal atoms are uniformly and densely coated on the carbon fiber surface, such as... Figure 1 As shown, the composite fiber has an average filament diameter of 17 μm, a surface metal atomic layer thickness of approximately 1.9 μm, an elastic modulus of 147 GPa, and a tensile strength of 950 MPa.

[0060] Application of Cf@MnCu-Al composite fiber reinforced aluminum alloy plate: Cf@MnCu was cut into short fibers with a length of 1±0.2 mm and thoroughly mixed with aluminum alloy powder. The mixture was placed in a ball mill jar with anhydrous ethanol as the mixing medium, a ball-to-powder ratio of 10:1, and milled for 0.5 h. After mixing, the material was placed in a hot press mold and then placed in a vacuum carbon tube hot press furnace. The hot pressing temperature was 600℃, the hot pressing pressure was 35 MPa, and the hot pressing time was 1 h, thus obtaining Cf@MnCu-Al, a high-efficiency and high-strength interfacial carbon fiber reinforced aluminum matrix composite plate. In the Cf@MnCu-Al composite plate, the composite carbon fiber and aluminum matrix interface bonded well, and no interfacial reaction was observed. Compared with the pure carbon fiber reinforced aluminum alloy plate Cf-Al, whose tensile strength is 40±3 MPa, the average tensile strength of the Cf@MnCu-Al composite plate increased by 30.6%.

[0061] Example 3:

[0062] Preparation of high-strength interfacial integrated multi-metal atomic layer coated pitch-based reinforced carbon fiber composite material (Cf@NiCuMn) and its application in the manufacture of composite carbon fiber reinforced aluminum matrix composite plate (Cf@NiCuMn-Al):

[0063] 1) Take 100g of coal tar pitch sample and place it in a melt spinning tank. Melt spinning is carried out at 300℃ and 1MPa to obtain pitch fiber.

[0064] 2) The pitch fiber was impregnated in a 5% (w / w) 1H-naphtho[2,3-d]imidazolium ethanol solution, removed after 20 min and vacuum dried at 60℃ for 3 h, and then placed in a forced-air drying oven for crosslinking at 230℃ for 10 h.

[0065] 3) The fiber obtained in step 2) was placed in a 2 mol / L nickel nitrate methanol solution and subjected to a solvothermal reaction at 130°C for 2 h. After the reaction was completed, it was naturally cooled to room temperature and rinsed three times with methanol and deionized water respectively, and then dried under vacuum at 60°C.

[0066] 4) Prepare a 3 mol / L nitrate-methanol mixed solution with a molar ratio of nickel, copper, and manganese ions of 1:1:1. Slowly add the solution dropwise to a 3 mol / L benzimidazole-methanol solution and stir vigorously to obtain a crystal film growth solution. Immerse the fiber obtained in step 3) in the crystal film growth solution and carry out a solvothermal reaction at 120°C for 2 hours. After the reaction is completed, allow it to cool naturally to room temperature and rinse it three times with methanol and deionized water, respectively. Then, dry it under vacuum at 60°C.

[0067] 5) Place the fiber sample obtained in step 4) in a N2 atmosphere with an airflow rate of 100 mL / min, heat it to 900℃ at a heating rate of 0.5℃ / min, and hold it for 3 h to obtain Cf@NiCuMn composite fiber.

[0068] Cf@NiCuMn composite fiber properties: Metal atoms are uniformly and densely wrapped on the carbon fiber surface, such as... Figure 2 As shown, the composite fiber has an average filament diameter of 23 μm, a surface metal atomic layer thickness of approximately 1.7 μm, an elastic modulus of 183 GPa, and a tensile strength of 1120 MPa.

[0069] Application in the manufacture of Cf@NiCuMn-Al composite aluminum alloy plates: Cf@NiCuMn was cut into short fibers with a length of 1±0.2 mm and thoroughly mixed with aluminum alloy powder. The mixture was then placed in a ball mill jar using anhydrous ethanol as the mixing medium at a ball-to-powder ratio of 10:1 and milled for 0.5 hours. The mixed material was then placed in a hot press mold and placed in a vacuum carbon tube hot press furnace at a temperature of 600℃, a pressure of 35 MPa, and a pressing time of 1 hour to obtain Cf@NiCuMn-Al, thus producing a high-efficiency, high-strength interfacial carbon fiber reinforced aluminum matrix composite plate. In the Cf@NiCuMn-Al composite plate, the composite carbon fiber and aluminum matrix showed good interfacial bonding, and no interfacial reaction was observed. Compared with pure carbon fiber reinforced aluminum alloy plate Cf-Al, whose tensile strength is 40±3 MPa, the average tensile strength of the Cf@NiCuMn-Al composite plate increased by 46.4%.

[0070] Comparative Example 1:

[0071] The surface functionalization of asphalt fibers was not performed using organic ligands containing polycyclic aromatic hydrocarbons.

[0072] The fibers were surface-treated with nitric acid, with other conditions referring to Example 1. The composite fiber structure was severely damaged, with obvious acidification marks on the surface, uneven filament diameter, poor dispersion of the surface metal atomic layer, and uneven thickness. Figure 3As shown, the composite fiber has relatively low strength, with an elastic modulus of 92 GPa and a tensile strength of 610 MPa. In its application in aluminum-based composite panels, compared to pure carbon fiber reinforced aluminum alloy panels (Cf-Al), which have a tensile strength of 40 ± 3 MPa, the tensile strength of this composite fiber aluminum-based composite panel is increased by 6.2%.

[0073] Due to the limited number of active functional groups on the fiber surface, surface functionalization is necessary to alter the chemically inert environment of the fiber surface in order to improve interfacial bonding. Commonly used surface modification methods easily damage the intrinsic structure of the fiber surface, reducing the bulk strength of the fiber. Moreover, heterogeneous nucleation of MOFs is difficult, requiring the provision of specific nucleation sites on the fiber surface to achieve confined reduction during subsequent pyrolysis, resulting in uniform and tightly adhered metal atom layers. Based on the molecular structure characteristics of asphaltene, this invention employs the introduction of specific polycyclic aromatic hydrocarbon structures (such as phenanthrene and naphthalene) into organic ligands, utilizing the π-π conjugation effect to perform non-destructive functionalization of the fiber surface. This simultaneously ensures the integrity of the fiber's bulk structure and strong interfacial bonding. Furthermore, the coordination bonds introduced into the fiber surface after non-destructive modification are the dominant forces between the ligand molecules and metal ions, providing nucleation sites for MOF formation and ensuring strong anchoring between the metal component and the carbon fiber carrier. The confined in-situ decomposition reaction ensures the high density and high dispersion of metal atoms on the fiber surface.

[0074] Comparative Example 2:

[0075] No secondary growth of MOFs was used for the preparation of crystalline films on fiber surfaces:

[0076] The fibers after surface synthesis of MOF crystals were directly carbonized without undergoing the solvothermal reaction in the MOF growth solution to obtain a secondary grown crystalline film. Other conditions were the same as in Example 1. The Ni metal atom layer on the fiber surface had a relatively small adhesion area, and the metal atoms were loosely attached, failing to form a dense metal film on the fiber surface. Figure 4 As shown, the composite fiber has an elastic modulus of 121 GPa and a tensile strength of 766 MPa. In its application in aluminum-based composite panels, compared to pure carbon fiber reinforced aluminum alloy panels (Cf-Al), which have a tensile strength of 40 ± 3 MPa, the tensile strength of this composite fiber aluminum-based composite panel is increased by 11.6%.

[0077] Since MOFs are rigid, crystalline powder structures, it is difficult to directly prepare continuous, defect-free MOF layers on the fiber surface. This invention further induces the epitaxial growth of MOFs, forming a crystalline film on the fiber surface through secondary MOF growth. This ultimately achieves a dense, uniformly dispersed layer of metal atoms that penetrates the fiber surface, improving not only the fiber surface's porosity, dislocations, and step structures, but also preventing interfacial reactions in the carbon fiber-reinforced aluminum matrix composite material, thus avoiding the formation of brittle phases and enhancing the buffering capacity of the connector to release internal and external stresses.

[0078] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing pitch-based reinforced carbon fiber composite materials based on metal-organic framework interfaces, characterized in that, Includes the following steps: 1) Using melt-spun pitch fiber as the carbon fiber matrix, surface functionalization is achieved through the π-π conjugation effect using organic ligands containing polycyclic aromatic hydrocarbons; 2) Using the organic ligand groups introduced on the surface of the fiber after non-destructive modification as nucleation sites for MOFs, MOFs crystals are synthesized on the surface of functionalized fibers by reacting with transition metal ions. 3) Further induce MOFs to grow on the surface of functionalized fibers to form a crystalline film; 4) Carbon fibers with an integrated metal atomic layer are obtained by high-temperature carbonization in an inert gas atmosphere.

2. The method for preparing pitch-based reinforced carbon fiber composite material based on a metal-organic framework interface according to claim 1, characterized in that, Specifically, the following steps are included: 1) Preparation of asphalt fiber substrate: Take a spinnable asphalt sample and place it in a melt spinning tank. Melt spin at 280~400℃ and 0.5~1.5MPa, and take-up linear speed is 600~1500m / min. 2) Surface functionalization treatment of asphalt fiber: Add organic ligands with polycyclic aromatic hydrocarbons to a solvent to prepare a solution with a mass fraction of 1%~10%; immerse the asphalt fiber obtained in step 1) in the solution for 10~30 min, vacuum dry at 60~70℃, and then place it in an air atmosphere for crosslinking stabilization at 150~250℃ for 4~20 h. 3) Synthesis of MOFs crystals on the surface of pitch fiber: The fiber obtained in step 2) was immersed in a methanol solution of transition metal salt and reacted solvothermically at 90~130℃ for 1~2h; after the reaction was completed, it was naturally cooled to room temperature and rinsed 2~3 times with methanol and deionized water respectively, and then vacuum dried at 60~70℃. 4) Preparation of MOF crystal film on the surface of pitch fiber: A MOF crystal film growth solution is prepared by mixing a transition metal salt methanol solution with an imidazole organic ligand methanol solution and stirring evenly. The fiber obtained in step 3) is immersed in the growth solution and subjected to a solvothermal reaction at 70~120℃ for 2~4h. After the reaction is completed, the fiber is naturally cooled to room temperature and rinsed 2~3 times with methanol and deionized water respectively, and then vacuum dried at 60~70℃. 5) Preparation of carbon fiber with integrated metal atomic layer coating: The fiber sample obtained in step 4) is placed in an inert gas atmosphere and carbonized at 800~1200℃ for 2~3h, with a heating rate of 0.5~5℃ / min and an air flow rate of 60~100mL / min.

3. The method for preparing pitch-based reinforced carbon fiber composite material based on a metal-organic framework interface according to claim 2, characterized in that, The diameter of the asphalt fiber substrate is 8~24μm.

4. The method for preparing pitch-based reinforced carbon fiber composite material based on a metal-organic framework interface according to claim 2, characterized in that, The organic ligand containing a polycyclic aromatic hydrocarbon is one of phenanthreneimidazole, naphthemidazole, or pyreneimidazole organic ligands.

5. The method for preparing pitch-based reinforced carbon fiber composite material based on a metal-organic framework interface according to claim 2, characterized in that, In step 2), the solvent is one or more of methanol, ethanol, and N,N-dimethylformamide.

6. The method for preparing pitch-based reinforced carbon fiber composite material based on a metal-organic framework interface according to claim 2, characterized in that, The transition metal is one or more of Ni, Cu, and Mn.

7. The method for preparing pitch-based reinforced carbon fiber composite material based on a metal-organic framework interface according to claim 2, characterized in that, The imidazole organic ligand is one of 2-methylimidazole, 4-methylimidazole, 1,2-dimethylimidazole, 2-ethyl-4-methylimidazole, and benzimidazole.

8. The method for preparing pitch-based reinforced carbon fiber composite material based on a metal-organic framework interface according to claim 2, characterized in that, The molar concentration of the transition metal salt methanol solution is 0.5~3 mol / L; the molar concentration of the imidazole organic ligand methanol solution is 0.1~3 mol / L.

9. An application of a pitch-based reinforced carbon fiber composite material based on a metal-organic framework interface, characterized in that, The pitch-based reinforced carbon fiber composite material based on the metal-organic framework interface as described in any one of claims 1-8 is used to manufacture a high-efficiency, high-strength interface carbon fiber reinforced aluminum matrix composite plate.

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