Low-temperature media leakage resistant carbon fiber composite material with self-healing and adaptive sealing functions, its preparation method and application

Abstract

This invention relates to the field of composite material technology, specifically to a low-temperature media leakage-proof carbon fiber composite material with self-healing and adaptive sealing functions, its preparation method, and its application. The preparation method of this composite material is as follows: S1. Add 4,4'-diaminodiphenyl ether and 3,5-diaminobenzoic acid-3-trifluoromethylphenyl ester to dimethylacetamide, stir, then add 4,4'-hexafluoroisopropylphthalic anhydride and stir. After raising to room temperature, continue stirring to obtain a fluorinated side-chain polyimide. Add MXene dispersion to the fluorinated side-chain polyimide to obtain a polyimide film layer. S2. Prepare a carbon fiber support layer. S3. Add an aromatic disulfide bond repair agent to water, then add isophorone diisocyanate and polyetheramine for reaction, and then mix with polyethylene terephthalate to obtain a self-healing leak-proof layer. S4. Prepare a double-layer gradient membrane. S5. Prepare the carbon fiber composite material.

Description

Technical Field

[0001] This invention relates to the field of composite material technology, specifically to a low-temperature media leakage-proof carbon fiber composite material with self-healing and adaptive sealing functions, its preparation method, and its application. Background Technology

[0002] The development of materials for aerospace launch vehicle tanks has primarily evolved from aluminum-magnesium alloys and aluminum-copper alloys to aluminum-lithium alloys, and is now moving towards carbon fiber composites. Carbon fiber composites far surpass metallic materials in specific strength and specific stiffness, while also possessing excellent fatigue resistance, vibration resistance, and superior formability. They are particularly suitable for large structures and integral structural molding, effectively reducing the number of components and connection processes, making them an ideal choice for achieving high performance and lightweight design in aerospace equipment.

[0003] Compared to traditional metal tanks, carbon fiber composite materials can reduce the weight of liquid oxygen tank structures by approximately 25%, and this weight reduction becomes even more significant as the size of cryogenic medium tanks increases, thus contributing to lower overall launch costs. Therefore, the research and application of carbon fiber composite tanks has become an inevitable trend. However, carbon fiber composite materials still face key challenges in practical applications. Although they possess certain oxidation resistance properties, key thermal performance parameters such as ignition point, flash point, and thermal decomposition temperature are all lower than those of metallic materials. Under high-energy instantaneous impact, the material may experience a rapid increase in local temperature, potentially leading to fire or even explosion. Therefore, improving the compatibility of carbon fiber composite materials with liquid oxygen has become a core issue that urgently needs to be addressed.

[0004] Furthermore, the significant difference in thermal expansion coefficients between carbon fiber and the resin matrix leads to high residual stress when the molded composite material cools from high temperature to room temperature or experiences large temperature differences under cryogenic tank conditions due to deformation mismatch. Under the coupling effect of internal mechanical stress, microcracks are easily induced at the resin matrix, fiber, and resin interface. In continuous or cyclic cryogenic and stressful environments, these microcracks gradually propagate, forming single-layer transverse cracks and interlaminar cracks, eventually developing into leakage channels and causing media leakage in the tank. Notably, under cryogenic conditions, leakage failure of carbon fiber composite tanks often precedes structural load-bearing failure. Therefore, effectively improving the compatibility of carbon fiber composites with cryogenic fuels and suppressing their leakage behavior in cryogenic environments has become crucial for promoting the engineering application of this type of material in cryogenic media tanks. Summary of the Invention

[0005] The primary objective of this invention is to provide a method for preparing a low-temperature media leakage-proof carbon fiber composite material with self-healing and adaptive sealing functions. The preparation method is simple and easy to implement.

[0006] The second objective of this invention is to provide a low-temperature media leakage-proof carbon fiber composite material with self-healing and adaptive sealing functions, exhibiting excellent anti-seepage and self-healing properties.

[0007] The third objective of this invention is to provide an application of a low-temperature media leakage-proof carbon fiber composite material with self-healing and adaptive sealing functions, which has broad application prospects.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0009] A method for preparing a low-temperature media leakage-resistant carbon fiber composite material with self-healing and adaptive sealing functions includes the following steps:

[0010] S1. Preparation of polyimide film layer

[0011] Add 4,4'-diaminodiphenyl ether and 3,5-diaminobenzoic acid-3-trifluoromethylphenyl ester to dimethylacetamide and stir for 0.5-1.5 h; then add 4,4'-hexafluoroisopropylphthalic anhydride at -5~0℃ and stir for 1-2 h, then raise to room temperature and continue stirring for 14-16 h. After removing impurities, obtain fluorinated side-chain polyimide; add MXene dispersion to the fluorinated side-chain polyimide, stir, degas, and coat to obtain a polyimide film layer for later use;

[0012] S2. Preparation of carbon fiber support layer

[0013] Carbon fiber / epoxy resin prepreg is laid up, and after vacuum depore removal, a carbon fiber support layer is obtained for later use.

[0014] S3. Preparation of a self-healing impermeable layer

[0015] An aromatic disulfide bond repair agent was added to water, followed by the addition of isophorone diisocyanate and polyetheramine for reaction. After the reaction was completed, the mixture was filtered and freeze-dried to obtain self-healing microcapsules containing dynamic disulfide bonds. The self-healing microcapsules containing dynamic disulfide bonds were mixed with polyethylene terephthalate, extruded and granulated, and then cast into a film to obtain the self-healing waterproof layer.

[0016] S4. Preparation of bilayer gradient film

[0017] The double-layer gradient membrane is prepared by co-extrusion process to combine the gradient transition layer with the self-healing impermeable layer; the gradient transition layer is made of fluorinated ethylene propylene copolymer.

[0018] S5. Preparation of carbon fiber composite materials

[0019] The polyimide film layer and the carbon fiber support layer are sequentially laid on the self-healing impermeable layer side of the double-layer gradient membrane, and then co-cured using a vacuum bag-autoclave process to obtain the carbon fiber composite material.

[0020] The self-healing microcapsules containing dynamic disulfide bonds of this invention have an average particle size of 15-30 μm, and the dynamic disulfide bonds can undergo a reversible exchange reaction within 10-30 min at 80-120℃ and 0.1-0.5 MPa. The wall material of the self-healing microcapsules containing dynamic disulfide bonds is prepared by in-situ interfacial polymerization, with an isocyanate index R=1.2-1.5, an encapsulation efficiency ≥85%, maintaining elasticity at -196℃, and an elongation at break of 5%±2%.

[0021] The gradient transition layer of this invention has an average linear expansion coefficient of (4–6) × 10⁻⁶ at 25–150 °C. -5 K -1 .

[0022] The polyimide film layer of the present invention has a glass transition temperature Tg=150-180℃ and can produce ≥2% reversible in-plane shrinkage deformation in the subglassy range of 80-120℃, which is used to actively close interfacial microcracks during thermal cycling.

[0023] Furthermore, the amount of MXene dispersion added in step S1 is 0.1-2 wt% of fluorinated side-chain polyimide; the MXene is Ti3C2T. X The thickness of the polyimide film layer is 20-60 μm.

[0024] Furthermore, the concentration of the MXene dispersion is 5-10 wt%.

[0025] The MXene of this invention is Ti3C2T X Its surface contains -F, -OH, and =O functional groups, with a sheet thickness of 1-3 nm and a lateral dimension of 0.2-1 μm. Under near-infrared 808 nm irradiation, the surface temperature can rise by ≥30℃ within 30 seconds, which can be used to trigger shape memory recovery.

[0026] Furthermore, the molar ratio of 4,4'-hexafluoroisopropylphthalic anhydride, 4,4'-diaminodiphenyl ether, and 3,5-diaminobenzoic acid-3-trifluoromethylphenyl ester in step S1 is 1:(0.5-1):(0.1-0.3).

[0027] Furthermore, the intrinsic viscosity of the fluorinated side-chain polyimide is 0.6-0.8 dL / g.

[0028] Furthermore, in step S2, the volume fraction of carbon fiber in the carbon fiber support layer is 55-70%, and the volume fraction of epoxy resin is 30-45%; the layup method is as follows: The thickness of the carbon fiber support layer is 1.4-2.2 mm.

[0029] Furthermore, in step S3, the molar ratio of the aromatic disulfide bond repair agent, isophorone diisocyanate, and polyetheramine is 1:(1.8-2.2):(0.9-1.1); the aromatic disulfide bond repair agent is 4,4'-dimercaptodiphenyl sulfide or 4,4-diaminodiphenyl sulfide; the mass ratio of the self-healing microcapsules containing dynamic disulfide bonds to polyethylene terephthalate is 1:(5-10); the self-healing microcapsules containing dynamic disulfide bonds account for 8-12 wt% of the total mass of the self-healing impermeable layer.

[0030] Furthermore, the reaction temperature in step S3 is 65-75℃, and the time is 2-4h; the twin-screw extrusion temperature in the extrusion granulation is 260-270℃; the casting film temperature is 260-270℃; and the thickness of the self-healing waterproof layer is 50-150μm.

[0031] Furthermore, in step S4, the co-extrusion process has a co-extrusion temperature of 260-270℃, a pressure of 5-10MPa, and a cooling roller temperature of 15-35℃; the thickness of the gradient transition layer is 30-100μm.

[0032] Furthermore, the curing temperature in step S5 is 180-200℃, and the curing pressure is 0.6-1MPa.

[0033] A carbon fiber composite material with self-healing and adaptive sealing functions for preventing low-temperature media leakage was prepared using the above method.

[0034] The aforementioned carbon fiber composite material with self-healing and adaptive sealing functions for preventing leakage of cryogenic media is used in the preparation of aerospace propellant tanks.

[0035] The beneficial technical effects of this invention are as follows:

[0036] 1. This invention provides a simple and easy method for preparing a carbon fiber composite material with self-healing and adaptive sealing functions that prevents leakage of low-temperature media.

[0037] 2. This invention provides a carbon fiber composite material with self-healing and adaptive sealing functions to prevent leakage of low-temperature media. This material is an intelligent anti-seepage composite material that integrates "active sensing, autonomous repair, and remote triggering". It is compatible with liquid oxygen and has high anti-seepage performance.

[0038] 3. This invention constructs a synergistic protection system consisting of molecular-level self-healing (microcapsules), macroscopic-level active compression (shape memory), and remote precise control (photothermal triggering). Specifically, on the one hand, this invention introduces self-healing microcapsules based on dynamic disulfide bonds into the impermeable layer for the first time. When microcracks occur, the capsules rupture and release the repair agent, enabling autonomous healing of cracks at the molecular level, transforming the irreversible process of "damage-leakage" into a reversible process of "damage-repair-functional recovery." On the other hand, this invention introduces a shape memory polyimide film containing MXene. MXene, as a highly efficient photothermal conversion agent, can generate localized heat under external near-infrared light irradiation, remotely and precisely triggering the shrinkage of the shape memory polymer, thereby compressing and deforming the interfacial microcracks to achieve macroscopic-scale active sealing. These three interact to form a comprehensive, multi-dimensional inhibition of the initiation and propagation of microcracks, solving technical problems that cannot be overcome by a single mechanism.

[0039] 4. After 100 cycles of high and low temperature cycling from -196℃ to +120℃, the carbon fiber composite material of the present invention exhibits a helium permeability of <1×10⁻⁶. -6 Pa·m³ / s; interlaminar shear strength retention rate ≥80%. In addition, this carbon fiber composite material has excellent in-service self-healing ability. After heat treatment at 80-120℃ for 30 minutes, the repair efficiency of surface microcracks can reach more than 80%, and the performance is almost completely restored. More importantly, with the help of the photothermal conversion properties of MXene, in-situ near-infrared light repair can be achieved without disassembly, providing a solution for the whole life cycle maintenance of aerospace equipment. Detailed Implementation

[0040] The following is a further detailed description of the present invention in conjunction with specific preferred embodiments, and it should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention. Specific conditions not specified in the embodiments are performed according to conventional conditions or conditions recommended by the manufacturer. Unless otherwise specified, all reagents or instruments used are conventional products obtained through commercial channels.

[0041] In the embodiments of the present invention, Ti3C2T X The surface contains -F, -OH, and =O functional groups, with a sheet thickness of 1-3 nm and a lateral dimension of 0.2-1 μm; the gradient transition layer is made of fluorinated ethylene propylene copolymer (FEP), with an average linear expansion coefficient of (4–6) × 10⁻⁶ at 25-150 °C. -5 K -1The glass transition temperature of the polyimide film layer is Tg=150-180℃, and it can produce ≥2% reversible in-plane shrinkage deformation in the subglassy range of 80-120℃, which can be used to actively close interfacial microcracks during thermal cycling.

[0042] Example 1

[0043] This embodiment provides a method for preparing a low-temperature media leakage-resistant carbon fiber composite material with self-healing and adaptive sealing functions, including the following steps:

[0044] S1. Preparation of polyimide film layer

[0045] Under nitrogen protection, dimethylacetamide was added to a reactor. The molar ratio of 4'-hexafluoroisopropylphthalic anhydride, 4,4'-diaminodiphenyl ether, and 3,5-diaminobenzoic acid-3-trifluoromethylphenyl ester was 1:0.8:0.2. At 0°C, 4,4'-diaminodiphenyl ether and 3,5-diaminobenzoic acid-3-trifluoromethylphenyl ester were added to the dimethylacetamide and stirred for 1 hour. 4,4'-hexafluoroisopropylphthalic anhydride was then slowly added in three portions, and stirring continued for 1.5 hours. The temperature was then raised to 25°C, and stirring continued for 15 hours to obtain a polyamic acid prepolymer. The resulting polyamic acid solution was filtered through a filter to remove unreacted particles and impurities, yielding a fluorinated side-chain polyimide with an intrinsic viscosity of 0.7 dL / g.

[0046] Ti3C2T X The mixture was added to dimethylacetamide and sonicated at 0°C for 20 min to obtain a Ti3C2T solution with a concentration of 8 wt%. X The dispersion; according to Ti3C2T X The dispersion was added at 1 wt% of the fluorinated side-chain polyimide, and Ti3C2T was added to the fluorinated side-chain polyimide. X The dispersion was stirred continuously for 2 hours; then transferred to a vacuum degassing device and degassed under vacuum (-0.09MPa) for 30 minutes at room temperature; then coated onto a glass plate by a blade coating method with a thickness controlled at 40μm; and vacuum treated at 120℃ for 4 hours to obtain a polyimide film layer for later use.

[0047] S2. Preparation of carbon fiber support layer

[0048] At 80℃ and 0.8MPa, 12K unidirectional carbon fibers and epoxy resin are pressed into a prepreg, cooled, coated with a release film, and then wound up. The carbon fiber support layer is laid up in a manner that allows for degassing at room temperature (-0.09 MPa, 10 min) every 3 layers. After a total of 8 layers, a carbon fiber support layer with a thickness of 2 mm is obtained and set aside. The carbon fiber support layer contains 60% carbon fiber and 40% epoxy resin by volume.

[0049] S3. Preparation of a self-healing impermeable layer

[0050] The molar ratio of 4,4'-dimercaptodiphenyl sulfide, isophorone diisocyanate, and polyetheramine was 1:2:1. 4,4'-dimercaptodiphenyl sulfide was added to water, followed by isophorone diisocyanate and polyetheramine ED-2003. The mixture was reacted at 70℃ for 3 hours. After the reaction was complete, the mixture was filtered and freeze-dried to obtain self-healing microcapsules containing dynamic disulfide bonds with an average particle size of 15-30 μm. The microcapsule wall material was prepared by in-situ interfacial polymerization, with an isocyanate index R = 1.2-1.5, an encapsulation efficiency ≥85%, and maintained elasticity at -196℃ with an elongation at break of 5%.

[0051] The self-healing microcapsules containing dynamic disulfide bonds were dispersed in polyethylene terephthalate at a mass ratio of 1:7. The mixture was then granulated by twin-screw extrusion at 260°C and cast into a film at 260°C to obtain a self-healing geomembrane with a thickness of 100 μm. The self-healing microcapsules containing dynamic disulfide bonds accounted for 8 wt% of the total mass of the self-healing geomembrane.

[0052] S4. Preparation of bilayer gradient film

[0053] A double-layer gradient membrane was prepared by combining a gradient transition layer with a thickness of 70 μm with the self-healing impermeable layer at 260℃ and 8 MPa.

[0054] S5. Preparation of carbon fiber composite materials

[0055] The polyimide film layer and the carbon fiber support layer are sequentially laid on the self-healing impermeable layer side of the double-layer gradient membrane. The temperature is increased to 190°C at 2°C / min and kept at that temperature for 3 hours. Then, a pressure of 0.7MPa is applied and kept at that pressure for 4 hours. After natural cooling to room temperature, the carbon fiber composite material is obtained.

[0056] Example 2

[0057] This embodiment provides a method for preparing a low-temperature media leakage-resistant carbon fiber composite material with self-healing and adaptive sealing functions, including the following steps:

[0058] S1. Preparation of polyimide film layer

[0059] Under nitrogen protection, dimethylacetamide was added to the reactor. The molar ratio of 4'-hexafluoroisopropylphthalic anhydride, 4,4'-diaminodiphenyl ether, and 3,5-diaminobenzoic acid-3-trifluoromethylphenyl ester was 1:0.5:0.1. The mixture was added at -4°C and stirred for 0.5 h. 4,4'-hexafluoroisopropylphthalic anhydride was then slowly added in two portions, with stirring continued for 1 h. The temperature was then raised to 25°C, and stirring continued for 14 h to obtain a polyamic acid prepolymer. The resulting polyamic acid solution was filtered through a filter to remove unreacted particles and impurities, yielding a fluorinated side-chain polyimide with an intrinsic viscosity of 0.6 dL / g. Ti3C2T X The mixture was added to dimethylacetamide and sonicated at 0°C for 20 min to obtain a 5wt% Ti3C2T solution. X The dispersion; according to Ti3C2T X The dispersion was added at 0.5 wt% of the fluorinated side-chain polyimide, and Ti3C2T was added to the fluorinated side-chain polyimide. X The dispersion was stirred continuously for 2 hours; then transferred to a vacuum degassing device and degassed under vacuum (-0.09MPa) for 30 minutes at room temperature; then coated onto a glass plate by a blade coating method with a thickness controlled at 20μm; and vacuum treated at 120℃ for 4 hours to obtain a polyimide film layer for later use.

[0060] S2. Preparation of carbon fiber support layer

[0061] At 80℃ and 0.8MPa, 12K unidirectional carbon fibers and epoxy resin are pressed into a prepreg, cooled, coated with a release film, and then wound up. The carbon fiber support layer is laid up in a manner that allows for degassing at room temperature (-0.09 MPa, 10 min) every 3 layers. After a total of 8 layers, a carbon fiber support layer with a thickness of 1.4 mm is obtained and set aside. The carbon fiber support layer contains 70% carbon fiber by volume and 30% epoxy resin by volume.

[0062] S3. Preparation of a self-healing impermeable layer

[0063] Following a molar ratio of 4,4'-dimercaptodiphenyl sulfide, isophorone diisocyanate, and polyetheramine of 1:1.8:0.9, 4,4'-dimercaptodiphenyl sulfide was added to water, followed by isophorone diisocyanate and polyetheramine ED-2003. The reaction was carried out at 65°C for 4 hours. After the reaction was completed, the mixture was filtered and freeze-dried to obtain self-healing microcapsules containing dynamic disulfide bonds with an average particle size of 15-30 μm. The microcapsule wall material was prepared by in-situ interfacial polymerization, with an isocyanate index R = 1.2-1.5. The encapsulation efficiency is ≥85%, it maintains elasticity at -196℃, and the elongation at break is 6%. The self-healing microcapsules containing dynamic disulfide bonds are dispersed in polyethylene terephthalate at a mass ratio of 1:5. The mixture is then granulated by twin-screw extrusion at 270℃ and cast into a film at 270℃ to obtain a 50μm thick self-healing geomembrane. The self-healing microcapsules containing dynamic disulfide bonds account for 8wt% of the total mass of the self-healing geomembrane.

[0064] S4. Preparation of bilayer gradient film

[0065] A double-layer gradient membrane was prepared by combining a 30μm thick gradient transition layer with the self-healing impermeable layer at 270℃ and 5MPa.

[0066] S5. Preparation of carbon fiber composite materials

[0067] The polyimide film layer and the carbon fiber support layer are sequentially laid on the self-healing impermeable layer side of the double-layer gradient membrane. The temperature is increased to 180°C at 2°C / min, kept at that temperature for 3 hours, and then pressure of 0.6MPa is applied and kept at that pressure for 4 hours. The membrane is then naturally cooled to room temperature and co-cured to obtain the carbon fiber composite material.

[0068] Example 3

[0069] This embodiment provides a method for preparing a low-temperature media leakage-resistant carbon fiber composite material with self-healing and adaptive sealing functions, including the following steps:

[0070] S1. Preparation of polyimide film layer

[0071] Under nitrogen protection, dimethylacetamide was added to the reactor. The molar ratio of 4'-hexafluoroisopropylphthalic anhydride, 4,4'-diaminodiphenyl ether, and 3,5-diaminobenzoic acid-3-trifluoromethylphenyl ester was 1:1:0.3. The mixture was added at -5°C and stirred for 1.5 h. 4,4'-hexafluoroisopropylphthalic anhydride was then slowly added in three portions, with stirring continued for 2 h. The temperature was then raised to 25°C, and stirring continued for 16 h to obtain a polyamic acid prepolymer. The resulting polyamic acid solution was filtered through a filter to remove unreacted particles and impurities, yielding a fluorinated side-chain polyimide with an intrinsic viscosity of 0.8 dL / g. Ti3C2T X The mixture was added to dimethylacetamide and sonicated at 0°C for 20 min to obtain a 10 wt% Ti3C2T solution. X The dispersion; according to Ti3C2T X The dispersion was added at 2 wt% of the fluorinated side-chain polyimide, and Ti3C2T was added to the fluorinated side-chain polyimide. X The dispersion was stirred continuously for 2 hours; then transferred to a vacuum degassing device and degassed under vacuum (-0.09MPa) for 30 minutes at room temperature; then coated onto a glass plate by a blade coating method with a thickness controlled at 60μm; and vacuum treated at 120℃ for 4 hours to obtain a polyimide film layer for later use.

[0072] S2. Preparation of carbon fiber support layer

[0073] At 80℃ and 0.8MPa, 12K unidirectional carbon fibers and epoxy resin are pressed into a prepreg, cooled, coated with a release film, and then wound up. The carbon fiber support layer is laid up in a manner that allows for degassing at room temperature (-0.09 MPa, 10 min) every 3 layers. After a total of 8 layers, a carbon fiber support layer with a thickness of 2.2 mm is obtained and set aside. The carbon fiber support layer contains 55% carbon fiber by volume and 45% epoxy resin by volume.

[0074] S3. Preparation of a self-healing impermeable layer

[0075] The molar ratio of 4,4-diaminodiphenyl sulfide, isophorone diisocyanate, and polyetheramine was 1:2.2:1.1. 4,4-diaminodiphenyl sulfide was added to water, followed by isophorone diisocyanate and polyetheramine ED-2003. The reaction was carried out at 75℃ for 2 hours. After the reaction was complete, the mixture was filtered and freeze-dried to obtain self-healing microcapsules containing dynamic disulfide bonds with an average particle size of 15-30 μm. The microcapsule wall material was prepared by in-situ interfacial polymerization, with an isocyanate index R = 1.2-1.5. Encapsulation... The efficiency is ≥85%, it maintains elasticity at -196℃, and the elongation at break is 7%. The self-healing microcapsules containing dynamic disulfide bonds are dispersed in polyethylene terephthalate at a mass ratio of 1:10. The mixture is then granulated by twin-screw extrusion at 265℃ and cast into a film at 265℃ to obtain a self-healing geomembrane with a thickness of 150μm. The self-healing microcapsules containing dynamic disulfide bonds account for 12wt% of the total mass of the self-healing geomembrane.

[0076] S4. Preparation of bilayer gradient film

[0077] A double-layer gradient membrane was prepared by combining a 100μm thick gradient transition layer with the self-healing impermeable layer at 265℃ and 10MPa.

[0078] S5. Preparation of carbon fiber composite materials

[0079] The polyimide film layer and the carbon fiber support layer are sequentially laid on the self-healing impermeable layer side of the double-layer gradient membrane. The temperature is increased to 200°C at 2°C / min, kept at that temperature for 3 hours, and then pressure of 1MPa is applied and kept at that pressure for 4 hours. The membrane is then naturally cooled to room temperature and co-cured to obtain the carbon fiber composite material.

[0080] Comparative Example 1

[0081] The difference between this comparative example and Example 1 is that step S1 is omitted, and Ti3C2T is added to the prepreg in step S2. X The dosage is the same as in Example 1.

[0082] Comparative Example 2

[0083] The difference between this comparative example and Example 1 is that 4,4'-dimercaptodiphenyl sulfide was not added in step S3, while the rest is the same as in Example 1.

[0084] Experimental Example

[0085] The performance of the materials obtained in Examples 1-3 and Comparative Examples 1-2 of the present invention was tested after 100 cycles of high and low temperature cycling from -196℃ to +120℃. The specific results are shown in Table 1.

[0086] Table 1

[0087]

[0088] As shown in Table 1, the carbon fiber composite material obtained in this invention exhibits a helium permeability of <1×10⁻¹⁹ after 100 cycles of high and low temperature cycling from -196℃ to +120℃. -6 Pa·m³ / s; interlaminar shear strength retention rate ≥80%. In addition, this carbon fiber composite material has excellent in-service self-healing ability. After heat treatment at 80-120℃ for 30 minutes, the repair efficiency of surface microcracks can reach more than 80%, and the performance is almost completely restored. More importantly, with the help of the photothermal conversion properties of MXene, in-situ near-infrared light repair can be achieved without disassembly, providing a solution for the whole life cycle maintenance of aerospace equipment.

[0089] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. The basic principles and main features of the present invention have been described above with specific implementation schemes. Based on the present invention, some modifications or substitutions can be made, but these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of protection claimed by the present invention.

Claims

1. A method for preparing a cryogenic medium leakage resistant carbon fiber composite material having self-repairing and self-adapting sealing function, characterized in that, Comprising the following steps: S1. Preparing a polyimide adhesive film layer 4,4'-diamino diphenyl ether, 3,5-diamino benzoic acid-3-trifluoromethyl phenyl ester is added to dimethylacetamide and stirred for 0.5-1.5h; then 4,4'-hexafluoroisopropyl phthalic anhydride is added at-5~0℃ and stirred for 1-2h, and after rising to room temperature, continue to stir for 14-16h, after impurity removal, obtain fluorine-containing side chain polyimide; MXene dispersion liquid is added to the fluorine-containing side chain polyimide, and after stirring, defoaming treatment and coating, a polyimide adhesive film layer is obtained, ready for use; S2. Preparing a carbon fiber bearing layer The carbon fiber / epoxy resin prepreg is laid up, and after vacuum degassing, a carbon fiber bearing layer is obtained, ready for use; S3. Preparing a self-repairing impermeable layer The aromatic disulfide bond repair agent is added to water, and then isophorone diisocyanate and polyether amine are added for reaction, after reaction is completed, filtration and freeze-drying, self-repairing microcapsules containing dynamic disulfide bond are obtained; the self-repairing microcapsules containing dynamic disulfide bond are mixed with polyethylene terephthalate, and after extrusion granulation and film casting, the self-repairing impermeable layer is prepared; S4. Preparing a double-layer gradient film The gradient transition layer and the self-repairing impermeable layer are compounded by co-extrusion process to prepare the double-layer gradient film; the gradient transition layer is made of fluorinated ethylene propylene copolymer; S5. Preparing a carbon fiber composite material The polyimide adhesive film layer and the carbon fiber bearing layer are sequentially laid on the self-repairing impermeable layer side of the double-layer gradient film, and after co-curing and molding by vacuum bag-heat press tank process, the carbon fiber composite material is obtained.

2. The method for preparing the low-temperature medium leakage resistant carbon fiber composite material with self-repairing and self-adapting sealing function according to claim 1, characterized in that, The MXene dispersion liquid in step S1 is added in an amount of 0.1-2wt% of the fluorine-containing side chain polyimide; the MXene is Ti3C2T X ; and the thickness of the polyimide adhesive film layer is 20-60μm.

3. The method for preparing the low-temperature media leakage-resistant carbon fiber composite material with self-healing and adaptive sealing functions according to claim 1, characterized in that, The molar ratio of 4,4'-hexafluoroisopropyl phthalic anhydride, 4,4'-diamino diphenyl ether and 3,5-diamino benzoic acid-3-trifluoromethyl phenyl ester in step S1 is 1:(0.5-1):(0.1-0.3).

4. The method for preparing the low-temperature media leakage-proof carbon fiber composite material with self-healing and adaptive sealing functions according to claim 1, characterized in that, The volume fraction of the carbon fibers in the carbon fiber bearing layer in step S2 is 55-70%, and the volume fraction of the epoxy resin is 30-45%; the laying manner is ; the thickness of the carbon fiber bearing layer is 1.4-2.2 mm.

5. The method for preparing the low-temperature media leakage-resistant carbon fiber composite material with self-healing and adaptive sealing functions according to claim 1, characterized in that, The molar ratio of the aromatic disulfide bond repair agent, isophorone diisocyanate and polyether amine in step S3 is 1:(1.8-2.2):(0.9-1.1); the aromatic disulfide bond repair agent is 4,4'-dimercaptodiphenyl sulfide or 4,4-diamino diphenyl sulfide; the mass ratio of the self-repairing microcapsules containing dynamic disulfide bond and polyethylene terephthalate is 1:(5-10); the self-repairing microcapsules containing dynamic disulfide bond account for 8-12wt% of the total mass of the self-repairing impermeable layer.

6. The method for preparing the low-temperature media leakage-proof carbon fiber composite material with self-healing and adaptive sealing functions according to claim 1, characterized in that, The reaction temperature in step S3 is 65-75℃, and the reaction time is 2-4h; the temperature of double screw extrusion in the extrusion granulation is 260-270℃; the temperature of film casting is 260-270℃; the thickness of the self-repairing impermeable layer is 50-150μm.

7. The method for preparing the low-temperature media leakage-proof carbon fiber composite material with self-healing and adaptive sealing functions according to claim 1, characterized in that, The co-extrusion temperature in the co-extrusion process in step S4 is 260-270℃, the pressure is 5-10MPa, and the cooling roller temperature is 15-35℃; the thickness of the gradient transition layer is 30-100μm.

8. The method for preparing the low-temperature media leakage-proof carbon fiber composite material with self-healing and adaptive sealing functions according to claim 1, characterized in that, The curing temperature in step S5 is 180-200℃, and the curing pressure is 0.6-1MPa.

9. A cryogenic medium leakage resistant carbon fiber composite material having self-repairing and self-adapting sealing function, characterized in that, Prepared by the method of any one of claims 1-8.

10. The use of the cryogenic medium leakage resistant carbon fiber composite material with self-repairing and self-adapting sealing function according to claim 9, characterized in that, In the preparation of a spacecraft propellant tank.

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