Carbon fiber composite material interface enhanced modulus decreasing interface transition layer construction method and product

Abstract

The invention provides a carbon fiber composite material interface enhanced modulus decreasing interface transition layer construction method and a product, and relates to the technical field of composite material interface enhancement. According to the interface transition layer construction method, an aminated metal organic framework NH2-UIO-66 and a zeolite imidazole framework material ZIF-8 are introduced to serve as middle layers, and finally polyether amine PEA is grafted; a modulus decreasing interface transition layer of a three-layer structure is constructed and used for reinforcing the carbon fiber composite material; wherein from inside to outside, the first layer of the transition layer is NH2-UIO-66, the second layer of the transition layer is ZIF-8, and the third layer of the transition layer is PEA. According to the scheme, the interfacial shear strength between pure carbon fibers and epoxy resin is improved by 95.8%, and the performance of the carbon fiber composite material can be effectively improved.

Description

Technical Field

[0001] This invention relates to the field of composite material interface reinforcement technology, and in particular to a method and product for constructing a modulus-decreasing interface transition layer for carbon fiber composite material interface reinforcement. Background Technology

[0002] Carbon fiber (CF), as a high-performance reinforcing material, is widely used in aerospace, automotive, and sporting goods fields due to its excellent specific strength, specific modulus, corrosion resistance, and fatigue resistance. Carbon fiber reinforced polymer (CFRP) uses carbon fiber as the reinforcing phase and polymer as the matrix, combining the advantages of both and becoming an important component of modern advanced materials. However, the interfacial properties between carbon fiber and the polymer matrix are a key factor restricting the macroscopic mechanical properties of CFRP. Due to the inertness of the carbon fiber surface, the lack of active groups, and the significant modulus difference between carbon fiber and the polymer matrix, the interfacial bonding strength is insufficient, and the stress transfer efficiency is low. Under load, the composite material is prone to interfacial debonding, which seriously affects the overall performance of the composite material. Therefore, designing the interface of the composite material to obtain excellent interfacial properties is the key to improving the mechanical properties of the composite material.

[0003] Traditional coating or grafting interface transition layer designs, such as Chinese patents with application numbers 202111636309.6, 202111636309.6, 202111061262.5, and 202310931106.2, can improve interface wettability and chemical bonding to some extent, but they still have problems with poor interfacial bonding strength, toughness, and overall mechanical properties of composite materials. Summary of the Invention

[0004] To address the above shortcomings, this invention provides a method and product for constructing a modulus-decreasing interface transition layer for carbon fiber composite materials, thereby improving the performance of carbon fiber composite materials.

[0005] In a first aspect, the present invention provides a method for constructing a modulus-decreasing interface transition layer for interfacial reinforcement of carbon fiber composites. By introducing an aminated metal-organic skeleton NH2-UIO-66 and a zeolite imidazole skeleton material ZIF-8 as an intermediate layer, and finally grafting polyetheramine PEA, a three-layer modulus-decreasing interface transition layer is constructed to reinforce carbon fiber composites. The transition layer consists of, from the inside out, NH2-UIO-66 as the first layer, ZIF-8 as the second layer, and PEA as the third layer.

[0006] Preferably, the method specifically includes the following steps:

[0007] Step S1: Desizing and acidifying the carbon fiber to remove impurities and slurry from the surface of the carbon fiber and introduce carboxylic acid groups, and then drying it in an oven for later use.

[0008] Step S2: Dissolve zirconium tetrachloride and the organic ligand 2-aminoterephthalic acid in DMF at a molar ratio of 4-1:1, add glacial acetic acid as a promoter, and prepare reactant solution I;

[0009] Step S3: Immerse the treated carbon fiber in the reactant solution I, and then transfer it to a reaction vessel with a polytetrafluoroethylene liner for 8-12 hours.

[0010] Step S4: After the reaction is complete, the carbon fiber after the reaction is washed several times with methanol and DMF in sequence. The dried carbon fiber is named CF-NH2-UIO-66.

[0011] Step S5: Dissolve 2-methylimidazole and zinc nitrate hexahydrate in DMF at a molar ratio of 10⁻⁵:1 to prepare reactant solution II;

[0012] Step S6: Completely immerse CF-NH2-UIO-66 in reactant solution II and react in a water bath at 20-40℃ for 2-6 hours;

[0013] Step S7: After the reaction is complete, the carbon fiber after the reaction is washed several times with methanol and DMF in sequence. The dried carbon fiber is named CF-NH2-UIO-66-ZIF-8.

[0014] Step S8: Dissolve PEA in DMF at a molar ratio of 0.3-1:1 to prepare reactant solution III;

[0015] Step S9: Completely immerse CF-NH2-UIO-66-ZIF-8 in reactant solution III and react in a water bath at 60-120℃ for 2-6 hours;

[0016] Step S10: After the reaction is complete, the carbon fiber after the reaction is washed several times with methanol and DMF in sequence. The dried carbon fiber is named CF-NH2-UIO-66-ZIF-8-PEA.

[0017] Step S11: CF-NH2-UIO-66-ZIF-8-PEA, epoxy resin and curing agent are mixed in a mass ratio of 0.01:100:85 and a gradient curing process is used to prepare carbon fiber resin matrix composite material.

[0018] Preferably, in step S2, the mass ratio of glacial acetic acid to zirconium tetrachloride is 10:1.

[0019] Preferably, in steps S2 and S3, the growth of NH2-UIO-66 is achieved by a solvothermal method; wherein the reaction solvent is DMF, the metal source is zirconium tetrachloride, and the organic ligand is 2-aminoterephthalic acid.

[0020] Preferably, the reaction temperature in step S3 is 110-130℃.

[0021] Preferably, in steps S5 and S6, the growth of ZIF-8 is achieved by room temperature or low temperature precipitation; wherein the zinc source is nitric acid hexahydrate, the organic ligand is 2-methylimidazole, and the solvent is methanol or ethanol.

[0022] Preferably, in steps S8 and S9, the grafting of PEA is achieved by a hydrothermal method.

[0023] Preferably, the molecular weight of the PEA is in the range of 200-2000 g / mol.

[0024] In a second aspect, the present invention provides a reinforced carbon fiber composite material prepared by means of a modulus-decreasing interface transition layer construction method for carbon fiber composite material interface reinforcement as described in any of the first aspects.

[0025] As can be seen from the above technical solution, the method for constructing a modulus-decreasing interface transition layer for carbon fiber composite materials proposed in this invention successfully constructs a modulus-decreasing interface transition layer with a unique three-layer structure by introducing an aminated metal-organic framework (NH2-UIO-66) and a zeolite imidazole framework material (ZIF-8) as intermediate layers, and finally grafting polyetheramine (PEA). This design not only fully utilizes the designability and porosity of MOF materials, as well as the flexibility and good compatibility with epoxy resin of PEA, but more importantly, by precisely controlling the growth and grafting sequence of each layer, it achieves effective modulus reduction and significant improvement in interface performance. The method of this invention overcomes the limitation of traditional modulus-decreasing interface transition layers being difficult to control gradient, providing a new idea and technical approach for the development of high-performance carbon fiber composite materials.

[0026] Compared to traditional interfacial transition layers, the gradient decreasing interfacial transition layer of this invention provides three continuous modulus transition interfaces, making the modulus change from high-modulus carbon fibers to low-modulus polymer matrices smoother and more gradual, effectively reducing the degree of modulus mismatch at each interface. This smooth transition minimizes stress concentration and improves stress transfer efficiency. When the composite material is under load, stress can be transferred layer by layer from the high-modulus region to the low-modulus region, avoiding sudden stress changes at a certain interface, thereby effectively reducing the risk of interfacial failure. This multi-level gradient design makes the stress distribution more uniform, avoiding the occurrence of stress peaks, thereby improving the overall mechanical properties of the composite material. Specifically, the interfacial shear strength between the functionalized carbon fibers and epoxy resin prepared by this invention can reach 78.7 MPa, which is 95.8% higher than the interfacial shear strength between pure carbon fibers and epoxy resin.

[0027] In terms of material selection, the first layer of NH2-UIO-66 in this application has advantages such as good bonding with carbon fiber, moderate modulus, regular pore structure, and the ability to provide subsequent growth sites. The second layer of ZIF-8 has advantages such as modulus balancing between the first and second layers, good flexibility and porosity, controllable in-situ growth, and good bonding with PEA. The third layer of PEA has advantages such as low modulus and high flexibility, good compatibility with the resin matrix, and multifunctionality. The selection of these three materials is based on their unique physicochemical properties and their synergistic effects in constructing multi-level modulus gradients, providing multiple bonding mechanisms, and achieving efficient stress buffering. This ingenious combination ensures a significant improvement in the interfacial properties of the final composite material, providing a solid foundation for the development of high-performance carbon fiber composite materials, and also reflects the originality and scientific nature of the material selection in this invention. Attached Figure Description

[0028] Figure 1 This is a flowchart illustrating a method for constructing a modulus-decreasing interface transition layer for interface reinforcement of carbon fiber composite materials, as provided in an embodiment of the present invention.

[0029] Figure 2 This is a cold field scanning electron microscope image of the fiber sample in Example 1 of the present invention.

[0030] Figure 3 This is a cold field scanning electron microscope image of the fiber sample in Comparative Example 2 of this invention.

[0031] Figure 4 This is a cold field scanning electron microscope image of the fiber sample in Comparative Example 3 of the present invention.

[0032] Figure 5 This is a cold field scanning electron microscope image of the fiber sample in Comparative Example 4 of this invention.

[0033] Figure 6The interfacial shear strength of the carbon fiber composite material in Example 1 and Comparative Examples 1-4 of this invention. Detailed Implementation

[0034] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] To address the shortcomings of existing carbon fiber reinforcement processes, such as poor interfacial bonding strength, toughness, and overall mechanical properties, and to further improve the performance of carbon fiber composites, this application proposes a three-layer structure with decreasing modulus interfacial transition layers. This structure is achieved by introducing an amino-modified metal-organic framework (NH2-UIO-66) and a zeolite imidazole framework (ZIF-8) as an intermediate layer, followed by grafting polyetheramine (PEA) onto the final layer. The transition layer is designed to reinforce carbon fiber composites. From the inside out, the first layer is NH2-UIO-66, the second is ZIF-8, and the third is PEA. Specifically, as shown... Figure 1 As shown, the method for constructing a modulus-decreasing interface transition layer for carbon fiber composite materials provided by the present invention can be implemented through the following steps:

[0036] Step S1: Desizing and acidifying the carbon fiber to remove impurities and slurry from the surface of the carbon fiber and introduce carboxylic acid groups, and then drying it in an oven for later use.

[0037] Step S2: Dissolve zirconium tetrachloride and the organic ligand 2-aminoterephthalic acid in N,N-dimethylformamide (DMF) at a molar ratio of 4-1:1, add glacial acetic acid as a promoter, and prepare reactant solution I;

[0038] Step S3: Immerse the treated carbon fiber in the reactant solution I, and then transfer it to a reaction vessel with a polytetrafluoroethylene liner for 8-12 hours.

[0039] Step S4: After the reaction is complete, the carbon fiber after the reaction is washed several times with methanol and DMF in sequence. The dried carbon fiber is named CF-NH2-UIO-66.

[0040] Step S5: Dissolve 2-methylimidazole and zinc nitrate hexahydrate in DMF at a molar ratio of 10⁻⁵:1 to prepare reactant solution II;

[0041] Step S6: Completely immerse CF-NH2-UIO-66 in reactant solution II and react in a water bath at 20-40℃ for 2-6 hours;

[0042] Step S7: After the reaction is complete, the carbon fiber after the reaction is washed several times with methanol and DMF in sequence. The dried carbon fiber is named CF-NH2-UIO-66-ZIF-8.

[0043] Step S8: Dissolve phenylethylamine (PEA) in DMF at a molar ratio of 0.3-1:1 to prepare reactant solution III;

[0044] Step S9: Completely immerse CF-NH2-UIO-66-ZIF-8 in reactant solution III and react in a water bath at 60-120℃ for 2-6 hours;

[0045] Step S10: After the reaction is complete, the carbon fiber after the reaction is washed several times with methanol and DMF in sequence. The dried carbon fiber is named CF-NH2-UIO-66-ZIF-8-PEA.

[0046] Step S11: CF-NH2-UIO-66-ZIF-8-PEA, epoxy resin and curing agent are mixed in a mass ratio of 0.01:100:85 and a gradient curing process is used to prepare carbon fiber resin matrix composite material.

[0047] In one embodiment, the mass ratio of glacial acetic acid to zirconium tetrachloride in step S2 is 10:1.

[0048] In one embodiment, the growth of NH2-UIO-66 in steps S2 and S3 is achieved by a solvothermal method; wherein the reaction solvent is DMF, the metal source is zirconium tetrachloride, and the organic ligand is 2-aminoterephthalic acid.

[0049] In one embodiment, the growth of ZIF-8 in steps S5 and S6 is achieved by room temperature or low temperature precipitation; wherein the zinc source is nitric acid hexahydrate, the organic ligand is 2-methylimidazole, and the solvent is methanol or ethanol.

[0050] In one embodiment, in steps S8 and S9, the grafting of PEA is achieved by a hydrothermal method; wherein the molecular weight of PEA is in the range of 200-2000 g / mol.

[0051] Furthermore, the present invention also provides a reinforced carbon fiber composite material, which is prepared by using a modulus-decreasing interface transition layer construction method for carbon fiber composite material interface reinforcement as described in any of the above embodiments.

[0052] The effectiveness of this scheme will be further explained below with reference to specific experiments.

[0053] Example 1:

[0054] (1) Desizing and acidification of carbon fiber, drying and keeping it for later use.

[0055] (2) Dissolve 0.044 g zirconium tetrachloride and 0.036 g 2-aminoterephthalic acid in DMF, add 0.44 g glacial acetic acid as a promoter, and prepare reaction solution I.

[0056] (3) Immerse the desized carbon fiber in reactant solution I, and then transfer it to a reaction vessel with a polytetrafluoroethylene liner and react at 120°C for 12 hours.

[0057] (4) After the reaction is complete, the carbon fiber after the reaction is washed several times with methanol and DMF in sequence. The dried fiber is named CF-NH2-UIO-66.

[0058] (5) Dissolve 0.205g of 2-methylimidazole and 0.149g of zinc nitrate hexahydrate in 6.15g of DMF to prepare reactant solution II.

[0059] (6) Completely immerse CF-NH2-UIO-66 in reactant solution II and react in a water bath at 38°C for 4 hours.

[0060] (7) After the reaction is complete, the CF-NH2-UIO-66 after the reaction is washed several times with methanol and DMF in sequence. The dried fiber is named CF-NH2-UIO-66-ZIF-8.

[0061] (8) Dissolve PEA in DMF at a molar ratio of 0.3-1:1 to prepare reactant solution III.

[0062] (9) Completely immerse CF-NH2-UIO-66-ZIF-8 in reactant solution III and react in a water bath at 90°C for 4 hours.

[0063] (10) After the reaction is complete, the fiber after the reaction is washed several times with methanol and DMF in sequence. The dried fiber is named CF-NH2-UIO-66-ZIF-8-PEA.

[0064] (11) CF-NH2-UIO-66-ZIF-8-PEA, epoxy resin, and curing agent were mixed at a mass ratio of 0.01:100:85 and carbon fiber resin-based composite material was prepared by gradient curing process.

[0065] Comparative Example 1:

[0066] (1) Desizing and acidification of carbon fiber, drying and keeping it for later use.

[0067] (2) The treated carbon fiber, epoxy resin and curing agent were mixed in a mass ratio of 0.01: 100: 85 and carbon fiber resin-based composite material was prepared by gradient curing process.

[0068] Comparative Example 2:

[0069] (1) Desizing and acidification of carbon fiber, drying and keeping it for later use.

[0070] (2) Dissolve 0.044 g zirconium tetrachloride and 0.036 g 2-aminoterephthalic acid in DMF, add 0.44 g glacial acetic acid as a promoter, and prepare reaction solution 1.

[0071] (3) Immerse the desized carbon fiber in reactant solution 1, and then transfer it to a reaction vessel with a polytetrafluoroethylene liner and react at 120°C for 12 hours.

[0072] (4) After the reaction is complete, the carbon fiber after the reaction is washed several times with methanol and DMF in sequence. The dried fiber is named CF-NH2-UIO-66.

[0073] (5) Dissolve PEA in DMF at a molar ratio of 0.3-1:1 to prepare reactant solution 2.

[0074] (6) Completely immerse CF-NH2-UIO-66 in reactant solution 2 and react in a water bath at 90°C for 4 hours.

[0075] (7) After the reaction is complete, the fiber after the reaction is washed several times with methanol and DMF in sequence. The dried fiber is named CF-NH2-UIO-66-PEA.

[0076] (8) Dissolve 0.205g of di-methylimidazole and 0.149g of zinc nitrate hexahydrate in 6.15g of DMF to prepare reactant solution 3.

[0077] (9) Completely immerse CF-NH2-UIO-66-PEA in reactant solution 3 and react in a water bath at 38°C for 4 hours.

[0078] (10) After the reaction is complete, the CF-NH2-UIO-66 after the reaction is washed several times with methanol and DMF in sequence. The dried fiber is named CF-NH2-UIO-66-PEA-ZIF-8.

[0079] (11) CF-NH2-UIO-66-PEA-ZIF-8 was mixed with epoxy resin and curing agent at a mass ratio of 0.01:100:85 and carbon fiber resin-based composite material was prepared by gradient curing process.

[0080] Comparative Example 3:

[0081] (1) Desizing and acidification of carbon fiber, drying and keeping it for later use.

[0082] (2) Dissolve 0.205g of di-methylimidazol and 0.149g of zinc nitrate hexahydrate in 6.15g of DMF to prepare reactant solution 1.

[0083] (3) Immerse CF completely in reactant solution 1 and react in a water bath at 38°C for 4 hours.

[0084] (4) After the reaction is complete, the CF after the reaction is washed several times with methanol and DMF in sequence, and the dried fiber is named CF-ZIF-8.

[0085] (5) Dissolve PEA in DMF at a molar ratio of 0.3-1:1 to prepare reactant solution 2.

[0086] (6) Immerse CF-ZIF-8 completely in reactant solution 2 and react in a water bath at 90°C for 4 hours.

[0087] (7) After the reaction is complete, the fiber after the reaction is washed several times with methanol and DMF in sequence. The dried fiber is named CF-ZIF-8-PEA.

[0088] (8) Dissolve 0.044 g zirconium tetrachloride and 0.036 g 2-aminoterephthalic acid in DMF, add 0.44 g glacial acetic acid as a promoter, and prepare reaction solution 3.

[0089] (9) Immerse CF-ZIF-8-PEA in reactant solution 3, and then transfer it to a reaction vessel with a polytetrafluoroethylene liner and react at 120°C for 12 h.

[0090] (10) After the reaction is complete, the carbon fiber after the reaction is washed several times with methanol and DMF in sequence. The dried fiber is named CF-ZIF-8-PEA-NH2-UIO-66.

[0091] (11) CF-ZIF-8-PEA-NH2-UIO-66 was mixed with epoxy resin and curing agent at a mass ratio of 0.01:100:85 and carbon fiber resin-based composite material was prepared by gradient curing process.

[0092] Comparative Example 4:

[0093] (1) Desizing and acidification of carbon fiber, drying and keeping it for later use.

[0094] (2) Dissolve PEA in DMF at a molar ratio of 0.3-1:1 to prepare reactant solution 1.

[0095] (3) Immerse CF completely in reactant solution 1 and react in a 90°C water bath for 4 hours.

[0096] (4) After the reaction is complete, the fiber after the reaction is washed several times with methanol and DMF in sequence, and the dried fiber is named CF-PEA.

[0097] (5) Dissolve 0.205g of di-methylimidazol and 0.149g of zinc nitrate hexahydrate in 6.15g of DMF to prepare reactant solution 2.

[0098] (6) Immerse CF completely in reactant solution 2 and react in a water bath at 38°C for 4 hours.

[0099] (7) After the reaction is complete, the CF after the reaction is washed several times with methanol and DMF in sequence, and the dried fiber is named CF-PEA-ZIF-8.

[0100] (8) Dissolve 0.044 g zirconium tetrachloride and 0.036 g 2-aminoterephthalic acid in DMF, add 0.44 g glacial acetic acid as a promoter, and prepare reaction solution 3.

[0101] (9) Immerse CF-PEA-ZIF-8 in reactant solution 3, and then transfer it to a reaction vessel with a polytetrafluoroethylene liner and react at 120°C for 12 hours.

[0102] (10) After the reaction is complete, the carbon fiber after the reaction is washed several times with methanol and DMF in sequence. The dried fiber is named CF-PEA-ZIF-8-NH2-UIO-66.

[0103] (11) CF-PEA-ZIF-8-NH2-UIO-66 was mixed with epoxy resin and curing agent at a mass ratio of 0.01:100:85 and carbon fiber resin-based composite material was prepared by gradient curing process.

[0104] like Figure 2-5 The images shown are cold field scanning electron microscope (SEM) images of fiber samples from Example 1, Comparative Example 2, Comparative Example 3, and Comparative Example 4, respectively. It can be seen from the images that after treatment with NH2-UIO-66 (… Figure 2The NH2-UIO-66 crystals effectively filled these grooves and formed a uniform coating on the fiber surface. Subsequent treatment with ZIF-8 introduced a layer of ZIF-8 nanoparticles into the carbon fibers. Finally, the deposition of PEA allowed the polymer to penetrate into the gaps between the NH2-UIO-66 and ZIF-8 crystal frameworks, acting as a binder to tightly connect the two MOF layers, ultimately forming a three-layer gradient structure (CF-NH2-UIO-66-ZIF-8-PEA). This gradient structure improves the surface roughness of the fiber and enhances wettability, thereby effectively improving the mechanical interlocking between the fiber and the matrix. Similarly, by changing the processing order of NH2-UIO-66, ZIF-8, and PEA, CF-NH2-UIO-66-PEA-ZIF-8 was also successfully prepared. Figure 3 ), CF-ZIF-8-PEA-NH2-UIO-66 ( Figure 4 ) and CF-PEA-ZIF-8-NH2-UIO-66 ( Figure 5 Gradient layers. After curing, these gradient layers transform into interface transition layers of a certain thickness, which helps to promote effective stress transfer and energy dissipation.

[0105] Furthermore, such as Figure 6 The figures show the interfacial shear strength of the carbon fiber composite materials in Embodiment 1 and Comparative Examples 1-4 of the present invention. As can be seen from the figures, compared to the traditional method of directly reinforcing resin with carbon fiber, constructing a three-layer transition layer comprising NH2-UIO-66, ZIF-8, and PEA can improve the mechanical properties. Furthermore, by employing the method proposed in this application, which constructs an interface with decreasing modulus from the inside out, using NH2-UIO-66 as the first layer, ZIF-8 as the second layer, and PEA as the third layer, the performance can be significantly improved. Compared to the traditional method, the interfacial shear strength can be increased from 40.2 MPa to 78.7 MPa, an increase of 95.8%, which is also significantly better than the methods using different processing sequences in other comparative examples.

[0106] The modules or units in the device of this invention can be merged, divided, and deleted according to actual needs. The above-disclosed embodiments are merely preferred embodiments of the present invention and should not be construed as limiting the scope of the invention. Those skilled in the art will understand that implementing all or part of the processes of the above embodiments and making equivalent changes according to the claims of this invention still fall within the scope of the invention.

Claims

1. A method for constructing a modulus-decreasing interfacial transition layer for interfacial reinforcement in carbon fiber composites, characterized in that, By introducing an aminated metal-organic framework NH2-UIO-66 and a zeolite imidazole framework material ZIF-8 as an intermediate layer, and finally grafting polyetheramine PEA, a three-layer modulus-decreasing interface transition layer is constructed to reinforce carbon fiber composites. The first layer of the transition layer is NH2-UIO-66, the second layer is ZIF-8, and the third layer is PEA.

2. The method for constructing a modulus-decreasing interface transition layer for carbon fiber composite material interface reinforcement according to claim 1, characterized in that, The method specifically includes the following steps: Step S1: Desizing and acidifying the carbon fiber to remove impurities and slurry from the surface of the carbon fiber and introduce carboxylic acid groups, and then drying it in an oven for later use. Step S2: Dissolve zirconium tetrachloride and the organic ligand 2-aminoterephthalic acid in DMF at a molar ratio of 4-1:1, add glacial acetic acid as a promoter, and prepare reactant solution I; Step S3: Immerse the treated carbon fiber in the reactant solution I, and then transfer it to a reaction vessel with a polytetrafluoroethylene liner for 8-12 hours. Step S4: After the reaction is complete, the carbon fiber after the reaction is washed several times with methanol and DMF in sequence. The dried carbon fiber is named CF-NH2-UIO-66. Step S5: Dissolve 2-methylimidazole and zinc nitrate hexahydrate in DMF at a molar ratio of 10⁻⁵:1 to prepare reactant solution II; Step S6: Completely immerse CF-NH2-UIO-66 in reactant solution II and react in a water bath at 20-40℃ for 2-6 hours; Step S7: After the reaction is complete, the carbon fiber after the reaction is washed several times with methanol and DMF in sequence. The dried carbon fiber is named CF-NH2-UIO-66-ZIF-8. Step S8: Dissolve PEA in DMF at a molar ratio of 0.3-1:1 to prepare reactant solution III; Step S9: Completely immerse CF-NH2-UIO-66-ZIF-8 in reactant solution III and react in a water bath at 60-120℃ for 2-6 hours; Step S10: After the reaction is complete, the carbon fiber after the reaction is washed several times with methanol and DMF in sequence. The dried carbon fiber is named CF-NH2-UIO-66-ZIF-8-PEA. Step S11: CF-NH2-UIO-66-ZIF-8-PEA, epoxy resin and curing agent are mixed in a mass ratio of 0.01:100:85 and a gradient curing process is used to prepare carbon fiber resin matrix composite material.

3. The method for constructing a modulus-decreasing interface transition layer for carbon fiber composite material interface reinforcement according to claim 2, characterized in that, In step S2, the mass ratio of glacial acetic acid to zirconium tetrachloride is 10:

1.

4. The method for constructing a modulus-decreasing interface transition layer for carbon fiber composite material interface reinforcement according to claim 2, characterized in that, In steps S2 and S3, the growth of NH2-UIO-66 is achieved by a solvothermal method; wherein the reaction solvent is DMF, the metal source is zirconium tetrachloride, and the organic ligand is 2-aminoterephthalic acid.

5. The method for constructing a modulus-decreasing interface transition layer for carbon fiber composite material interface reinforcement according to claim 2, characterized in that, The reaction temperature in step S3 is 110-130℃.

6. The method for constructing a modulus-decreasing interface transition layer for carbon fiber composite materials according to claim 2, characterized in that, In steps S5 and S6, ZIF-8 is grown by room temperature or low temperature precipitation; wherein the zinc source is nitric acid hexahydrate, the organic ligand is 2-methylimidazole, and the solvent is methanol or ethanol.

7. The method for constructing a modulus-decreasing interface transition layer for carbon fiber composite material interface reinforcement according to claim 2, characterized in that, In steps S8 and S9, the grafting of PEA is achieved by a hydrothermal method.

8. The method for constructing a modulus-decreasing interface transition layer for carbon fiber composite materials according to claim 6, characterized in that, The molecular weight range of the PEA is 200-2000 g / mol.

9. A reinforced carbon fiber composite material, characterized in that, The reinforced carbon fiber composite material is prepared using the modulus-decreasing interface transition layer construction method for carbon fiber composite material interface reinforcement as described in any one of claims 1-8.

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