A carbon fiber composite material for preventing low-temperature medium leakage and its preparation method and application

Abstract

The present invention belongs to the technical field of composite materials, and specifically relates to a carbon fiber composite material for preventing leakage of low-temperature media, and its preparation method and application. The carbon fiber composite material includes carbon fiber, resin matrix, modified nano-hydroxyapatite and anti-seepage film; the mass percentage of the carbon fiber is 45-69%, the mass percentage of the resin matrix is ​​26-37%, the mass percentage of the anti-seepage film is 2-10%, and the modified nano-hydroxyapatite is the remainder; the present invention adds modified nano-hydroxyapatite, anti-seepage film and other raw materials to the formula of the carbon fiber composite material, and the two comprehensively improve the anti-seepage performance of the carbon fiber composite material in low-temperature media. Experimental results show that the thickness of the carbon fiber composite material is less than 3 mm, and the leakage rate is less than 10 at 3 MPa. <supgt;‑5< / supgt; Pa·m<supgt;3< / supgt; / s。

Description

Technical Field

[0001] The invention belongs to the technical field of composite materials, and in particular relates to a carbon fiber composite material for preventing low-temperature medium leakage, and a preparation method and application thereof. Background Art

[0002] The development of space vehicle tank materials has mainly gone through the stages of aluminum-magnesium alloys, aluminum-copper alloys, and aluminum-lithium alloys, and finally developed towards carbon fiber composite materials. The specific strength and specific stiffness of carbon fiber composite materials are much higher than those of metals, and they have good fatigue resistance, seismic resistance, and good molding processability, and can reduce the number of parts and connection processes. They are particularly suitable for large structures and overall structural molding. Compared with metal tanks, carbon fiber composite materials can reduce the weight of liquid oxygen tank structures by about 25%, and the larger the size of the cryogenic medium tank structure, the more obvious the weight reduction effect, and at the same time it is conducive to reducing the overall launch cost. It can be seen that the development of carbon fiber composite tanks is of great significance.

[0003] Due to the obvious difference between the thermal expansion coefficient of carbon fiber and the thermal expansion coefficient of the resin matrix, when the carbon fiber composite material is cooled from the molding temperature to room temperature, and when it is used in cryogenic storage tanks such as liquid oxygen (-183℃) and liquid hydrogen (-252℃), there is a huge temperature difference between the carbon fiber composite material and the epoxy resin. The mismatch in thermal expansion will cause the deformation of the carbon fiber and the epoxy resin to be uncoordinated, resulting in high residual stress generated by the carbon fiber composite material during low-temperature cooling. Under the coupling of internal mechanical stress, microcracks are easily generated in the resin matrix and at the interface between the carbon fiber and the resin. Under the continuous or cyclic action of low temperature and stress, the microcracks continue to expand until a single-layer transverse crack and interlayer crack are formed, and then a leakage channel is formed, causing the tank to leak. Under the action of low-temperature media, the leakage failure of the carbon fiber composite cryogenic storage tank will occur before the structural bearing failure. Therefore, how to effectively suppress the leakage problem of carbon fiber composite materials in cryogenic media is the key to the application of carbon fiber composite materials in cryogenic medium storage tanks.

[0004] In order to improve the low-temperature medium leakage resistance of carbon fiber composite materials, the prior art usually introduces flexible polymers (such as thermoplastic resins, nano rubbers, etc.) into the resin matrix, such as patent CN113861619A; or by doping nanomaterials (such as carbon nanotubes, graphene, silica, etc.) to improve the toughness of the resin matrix, so as to improve the ability to resist crack propagation and reduce the risk of leakage, such as patents CN103435975B and CN117887211A. However, these two methods cannot fundamentally solve the problem of residual stress causing microcracks. The introduction of flexible polymers will increase the thermal expansion coefficient of the epoxy resin matrix. When the ambient temperature of the carbon fiber reinforced resin-based composite material drops from room temperature to ultra-low temperature, the thermal expansion coefficient of the resin matrix is ​​large, which causes the temperature stress of the resin / fiber interface to increase sharply, which in turn easily leads to the initiation of microcracks at the resin / fiber interface, and may eventually reduce the low-temperature medium leakage resistance of the carbon fiber resin-based composite material. However, the addition of nanomaterials cannot guarantee the dispersion of the nanomaterials in the resin matrix, and agglomeration is prone to occur, resulting in a decrease in the mechanical properties of carbon fiber composites. In addition, the surface of the nanomaterials may have no active functional groups, which will result in no covalent bonding between the nanomaterials and the resin matrix, thereby making the interface bonding between the nanomaterials and the resin matrix weaker.

[0005] In view of the above problems, the present invention proposes an innovative solution: inserting an anti-seepage film into the surface layer and interlayer of the carbon fiber composite material to effectively solve the leakage problem of the low-temperature medium in the carbon fiber composite material, thereby ensuring that the low-temperature medium cannot leak. Summary of the invention

[0006] One of the purposes of the present invention is to provide a carbon fiber composite material for preventing low-temperature medium leakage, which has excellent anti-seepage performance.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] A carbon fiber composite material for preventing low-temperature medium leakage, the carbon fiber composite material comprising carbon fiber, a resin matrix, modified nano-hydroxyapatite and an impermeable film; the mass percentage of the carbon fiber is 45-69%, the mass percentage of the resin matrix is ​​26-37%, the mass percentage of the impermeable film is 2-10%, and the modified nano-hydroxyapatite is the remainder;

[0009] The preparation method of the modified nano-hydroxyapatite is as follows: nano-hydroxyapatite, decanoic acid and carboxymethyl cellulose are added into a solvent for reaction to obtain the modified nano-hydroxyapatite.

[0010] Furthermore, the mass ratio of the carboxymethyl cellulose, nano-hydroxyapatite and capric acid is 1: (0.5-1): (1.5-3); the solvent is an ethanol aqueous solution; the mass concentration of ethanol in the ethanol aqueous solution is 65-75wt%; the reaction temperature is 95-105°C, and the reaction time is 4-5h.

[0011] Furthermore, the anti-seepage film is a surface-treated film; the surface treatment method is selected from one or more of plasma treatment, sodium treatment, physical vapor deposition, chemical vapor deposition, solution method, and polishing.

[0012] Furthermore, the material of the anti-seepage film is selected from one or more of ethylene-tetrafluoroethylene copolymer, polytetrafluoroethylene, polyperfluoroethylene-propylene, polychlorotrifluoroethylene, perfluoroalkoxy vinyl ether copolymer, polyvinyl fluoride, and polyvinylidene fluoride.

[0013] Furthermore, the resin matrix is ​​a thermoplastic resin matrix or a thermosetting resin matrix; the thermoplastic resin matrix is ​​selected from one of polyamide, polycarbonate, polyurethane, polyethylene terephthalate, polyphenylene sulfide, polysulfone, polyimide, polyarylate, liquid crystal polymer, polyetheretherketone, polyetherketoneketone, polytetrafluoroethylene, polyvinylidene fluoride, and polychlorotrifluoroethylene; the thermosetting resin matrix is ​​selected from one of epoxy resin, polyimide, phenolic resin, unsaturated polyester resin, amino resin, furan resin, silicone resin, polyurethane, and vinyl resin.

[0014] Furthermore, the cryogenic medium is one of liquid oxygen, liquid hydrogen, liquid natural gas, liquid petroleum gas, and liquid nitrogen.

[0015] A second object of the present invention is to provide a method for preparing a carbon fiber composite material that is resistant to leakage of low-temperature media, and the preparation method is simple and easy.

[0016] To achieve the above object, the present invention adopts the following technical solutions:

[0017] The method for preparing the carbon fiber composite material for preventing low-temperature medium leakage comprises the following steps:

[0018] Method (1): According to the mass percentage of each component in the carbon fiber composite material, carbon fiber, resin matrix, and modified nano-hydroxyapatite are prepared into prepreg, and then the surface-treated anti-seepage film is spread between the layers and / or on the surface of the prepreg layer, and the carbon fiber composite material for preventing low-temperature medium leakage is prepared by a composite material molding process;

[0019] Method (2): According to the mass percentage of each component in the carbon fiber composite material, the resin matrix and the modified nano-hydroxyapatite are uniformly mixed to obtain a mixture of the two; then the surface-treated anti-seepage film, the resin matrix and the mixture of the modified nano-hydroxyapatite are respectively spread on the surface layer and / or between the layers of the carbon fiber layer, and then a composite material molding process is used to prepare the carbon fiber composite material for preventing low-temperature medium leakage;

[0020] Method (3): According to the mass percentage of each component in the carbon fiber composite material, the surface treated anti-seepage film is spread on the surface and / or between the layers of the carbon fiber ply, the resin matrix and the modified nano-hydroxyapatite are evenly mixed, and then the resin matrix is ​​infused into the interior of the carbon fiber through a vacuum assisted infusion process or a resin transfer molding process, and heated and cured.

[0021] Furthermore, the molding process in method (1) and method (2) is a molding process or an autoclave process.

[0022] Furthermore, the resin matrix in method (2) is a thermoplastic resin matrix; and the resin matrix in method (3) is a thermosetting resin matrix.

[0023] The third purpose of the present invention is to provide an application of a carbon fiber composite material for preventing leakage of low-temperature media, which has broad application prospects.

[0024] To achieve the above object, the present invention adopts the following technical solutions:

[0025] The above-mentioned carbon fiber composite material that prevents leakage of low-temperature media is used in the preparation of aerospace propellant tanks.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] (1) The carbon fiber composite material formula of the present invention adds modified nano-hydroxyapatite, anti-seepage film and other raw materials. The modified nano-hydroxyapatite reduces the agglomeration phenomenon between nanoparticles through surface modification, so that it can be more evenly dispersed in the resin matrix. This uniform dispersion helps to reduce the defects and pores inside the carbon fiber composite material, thereby reducing the risk of leakage. Furthermore, the active functional groups on the surface of the modified nano-hydroxyapatite form covalent bonds with the resin matrix, which enhances the interfacial bonding force between the nanomaterial and the resin matrix, helps to improve the overall strength and sealing of the carbon fiber composite material, and further reduces the possibility of leakage. The modified nano-hydroxyapatite and anti-seepage film comprehensively improve the anti-seepage performance of the carbon fiber composite material.

[0028] (2) The present invention provides a carbon fiber composite material for preventing low-temperature medium leakage, wherein the thickness of the carbon fiber composite material is less than 3 mm and the leakage rate is less than 10 at 3 MPa.-5 Pa·m 3 / s.

[0029] (3) The method for preparing the carbon fiber composite material for preventing low-temperature medium leakage of the present invention is simple and easy to implement, and is suitable for industrial and large-scale applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a contact angle result diagram of an ethylene-tetrafluoroethylene copolymer film obtained in Example 1, both sides of which were subjected to vacuum plasma grafting treatment;

[0031] Figure 2 is a microstructure diagram of ethylene-tetrafluoroethylene copolymer films treated differently; Figure 2 Figure (a) is the microstructure of the untreated ethylene-tetrafluoroethylene copolymer film. Figure 2 Figure (b) is a microstructure diagram of the ethylene-tetrafluoroethylene copolymer film of Example 1, both sides of which were subjected to vacuum plasma grafting treatment. DETAILED DESCRIPTION

[0032] The technical solution of the present invention is further explained below in conjunction with specific embodiments, comparative examples, test examples and drawings.

[0033] In the following examples, comparative examples and test examples, the raw materials and preparation methods used are conventional materials and techniques in the art unless otherwise specified.

[0034] The carbon fiber in the embodiment of the present invention was purchased from Jiangsu Hengshen Co., Ltd., model number is T1100;

[0035] Polyetheretherketone: purchased from Jilin Zhongyan Polymer Materials Co., Ltd.

[0036] The carbon fiber / polyetheretherketone / modified nano-hydroxyapatite prepreg was homemade in the laboratory by the suspension method;

[0037] The anti-seepage film is a commercial ethylene-tetrafluoroethylene copolymer (ETFE) film purchased from Dongguan Jinqun Plastic Chemical Co., Ltd. with a thickness of 100 μm;

[0038] The carbon fiber / epoxy resin / modified nano-hydroxyapatite prepreg was homemade in the laboratory by the suspension method;

[0039] The particle size of nanohydroxyapatite is 50 nm;

[0040] Epoxy resin and DDS were purchased from Jiangsu Juncheng Space Technology Co., Ltd., and the model of epoxy resin is CJ602.

[0041] 1. Embodiment

[0042] The following are Examples 1-4 formed by method (1).

[0043] Example 1

[0044] Embodiment 1 provides a carbon fiber composite material for preventing low-temperature medium leakage, the carbon fiber composite material is composed of carbon fiber, polyetheretherketone, modified nano-hydroxyapatite and ethylene-tetrafluoroethylene copolymer; the mass percentage of the carbon fiber is 60%, the mass percentage of the polyetheretherketone is 28%, the mass percentage of the ethylene-tetrafluoroethylene copolymer is 7%, and the modified nano-hydroxyapatite is the balance. Both sides of the ethylene-tetrafluoroethylene copolymer are subjected to vacuum plasma grafting treatment in a mixed atmosphere of helium and acrylic acid (He / AA).

[0045] The preparation process of modified nano-hydroxyapatite is as follows:

[0046] According to the mass ratio of carboxymethyl cellulose, nano-hydroxyapatite and capric acid of 1:0.6:2, nano-hydroxyapatite, capric acid and carboxymethyl cellulose are added to an ethanol aqueous solution, the mass concentration of ethanol in the ethanol aqueous solution is 70wt%, and the mixture is reacted at 100°C for 4.5h to obtain the product.

[0047] Example 1 also provides a method for preparing the above-mentioned carbon fiber composite material for preventing low-temperature medium leakage, and the specific process is as follows:

[0048] According to the mass percentage of each component in the carbon fiber composite material, the carbon fiber / polyetheretherketone / modified nano-hydroxyapatite prepreg was laid in a [0 / 90 / +45 / -45]s manner (laying was performed at 0°, 90°, +45° and -45°, and the laying sequence was symmetrical), and the ethylene-tetrafluoroethylene copolymer film with vacuum plasma grafting treatment on both sides was coated on the surface of the carbon fiber / polyetheretherketone / modified nano-hydroxyapatite prepreg layer and between the layers of the symmetrical layer, and vacuum molding was performed, wherein the molding temperature was 380°C, the pressure was 2.5 MPa, and the molding time was 1 h, and a carbon fiber composite material with a thickness of about 1.5 mm was obtained.

[0049] Example 2

[0050] Embodiment 2 provides a carbon fiber composite material for preventing low-temperature medium leakage, the carbon fiber composite material is composed of carbon fiber, polyetheretherketone, modified nano-hydroxyapatite and ethylene-tetrafluoroethylene copolymer; the mass percentage of the carbon fiber is 69%, the mass percentage of the polyetheretherketone is 26%, the mass percentage of the ethylene-tetrafluoroethylene copolymer is 2%, and the modified nano-hydroxyapatite is the balance. Both sides of the ethylene-tetrafluoroethylene copolymer are subjected to vacuum plasma grafting treatment in a mixed atmosphere of helium and acrylic acid (He / AA).

[0051] The preparation process of modified nano-hydroxyapatite is as follows:

[0052] According to the mass ratio of carboxymethyl cellulose, nano-hydroxyapatite and capric acid of 1:0.5:1.5, nano-hydroxyapatite, capric acid and carboxymethyl cellulose are added to an ethanol aqueous solution, the mass concentration of ethanol in the ethanol aqueous solution is 65wt%, and the mixture is reacted at 95°C for 5h to obtain the product.

[0053] Example 2 also provides a method for preparing the above-mentioned carbon fiber composite material for preventing low-temperature medium leakage, and the specific process is as follows:

[0054] According to the mass percentage of each component in the carbon fiber composite material, the carbon fiber / polyetheretherketone / modified nano-hydroxyapatite prepreg was laid in a [0 / 90 / +45 / -45]s manner, and the ethylene-tetrafluoroethylene copolymer film with vacuum plasma grafting treatment on both sides was coated on the surface of the carbon fiber / polyetheretherketone / modified nano-hydroxyapatite prepreg layer, and the film was formed by vacuum molding process, wherein the molding temperature was 380℃, the pressure was 2.5 MPa, and the molding time was 1h, and a carbon fiber composite material with a thickness of about 1.5 mm was obtained.

[0055] Example 3

[0056] The only difference between Example 3 and Example 1 is that an ethylene-tetrafluoroethylene copolymer film, both sides of which have been subjected to vacuum plasma grafting treatment in a mixed atmosphere of helium and acrylic acid (He / AA), is coated between the layers of the symmetrically laid layers of carbon fiber / polyetheretherketone / modified nano-hydroxyapatite prepreg layers, and the rest is the same as Example 1.

[0057] Example 4

[0058] Embodiment 4 provides a carbon fiber composite material for preventing low-temperature medium leakage, the carbon fiber composite material is composed of carbon fiber, epoxy resin, modified nano-hydroxyapatite and ethylene-tetrafluoroethylene copolymer; the mass percentage of the carbon fiber is 45%, the mass percentage of the epoxy resin is 37%, the mass percentage of the ethylene-tetrafluoroethylene copolymer is 10%, and the modified nano-hydroxyapatite is the balance. Both sides of the ethylene-tetrafluoroethylene copolymer are subjected to vacuum plasma grafting treatment in a mixed atmosphere of helium and acrylic acid (He / AA).

[0059] The preparation process of modified nano-hydroxyapatite is as follows:

[0060] According to the mass ratio of carboxymethyl cellulose, nano-hydroxyapatite and capric acid of 1:1:3, nano-hydroxyapatite, capric acid and carboxymethyl cellulose are added to an ethanol aqueous solution, the mass concentration of ethanol in the ethanol aqueous solution is 75wt%, and the mixture is reacted at 105°C for 5h to obtain the product.

[0061] Example 4 also provides a method for preparing the above-mentioned carbon fiber composite material for preventing low-temperature medium leakage, and the specific process is as follows:

[0062] According to the mass percentage of each component in the carbon fiber composite material, the carbon fiber / epoxy resin / modified nano-hydroxyapatite prepreg was laid in a [0 / 90 / +45 / -45]s (0°, 90°, +45° and -45° ply, and the ply sequence was symmetrical), and the ethylene-tetrafluoroethylene copolymer film with vacuum plasma grafting treatment on both sides was inserted into the surface of the carbon fiber / epoxy resin / modified nano-hydroxyapatite prepreg ply and the interlayer of the symmetrical ply, and the vacuum molding process was adopted, wherein the molding temperature was 180°C, the pressure was 2.5 MPa, and the curing time was 6 h, and a carbon fiber composite material with a thickness of about 1.6 mm was obtained.

[0063] The following is Example 5 formed by method (2).

[0064] Example 5

[0065] Embodiment 5 provides a carbon fiber composite material for preventing low-temperature medium leakage, the carbon fiber composite material is composed of carbon fiber, polyetheretherketone, modified nano-hydroxyapatite and ethylene-tetrafluoroethylene copolymer; the mass percentage of the carbon fiber is 60%, the mass percentage of the polyetheretherketone is 28%, the mass percentage of the ethylene-tetrafluoroethylene copolymer is 7%, and the modified nano-hydroxyapatite is the balance. Both sides of the ethylene-tetrafluoroethylene copolymer are subjected to vacuum plasma grafting treatment in a mixed atmosphere of helium and acrylic acid (He / AA).

[0066] Example 5 also provides a method for preparing the above-mentioned carbon fiber composite material for preventing low-temperature medium leakage, and the specific process is as follows:

[0067] According to the mass percentage of each component in the carbon fiber composite material, polyetheretherketone and modified nano-hydroxyapatite were evenly mixed, and then the ethylene-tetrafluoroethylene copolymer film with vacuum plasma grafting treatment on both sides, the mixture of polyetheretherketone and modified nano-hydroxyapatite were respectively spread on the surface and interlayer of the carbon fiber, and formed by vacuum molding process, wherein the molding temperature was 380°C, the pressure was 2.5 MPa, and the molding time was 1 hour, and a carbon fiber composite material with a thickness of about 1.5 mm was obtained.

[0068] The following is Example 6 formed by method (3).

[0069] Example 6

[0070] Embodiment 6 provides a carbon fiber composite material for preventing low-temperature medium leakage, the carbon fiber composite material is composed of carbon fiber, epoxy resin, modified nano-hydroxyapatite and ethylene-tetrafluoroethylene copolymer; the mass percentage of the carbon fiber is 60%, the mass percentage of polyetheretherketone is 28%, the mass percentage of ethylene-tetrafluoroethylene copolymer is 7%, and the modified nano-hydroxyapatite is the balance. Both sides of the ethylene-tetrafluoroethylene copolymer are subjected to vacuum plasma grafting treatment in a mixed atmosphere of helium and acrylic acid (He / AA).

[0071] Example 6 also provides a method for preparing the above-mentioned carbon fiber composite material for preventing low-temperature medium leakage, and the specific process is as follows:

[0072] According to the mass percentage of each component in the carbon fiber composite material, the epoxy resin and the modified nano-hydroxyapatite are evenly mixed to obtain a mixture; the ethylene-tetrafluoroethylene copolymer film with vacuum plasma grafting treatment on both sides is spread on the surface and between the layers of the carbon fiber ply, and then the epoxy resin and modified nano-hydroxyapatite mixture is poured into the interior of the carbon fiber by resin transfer molding process, and the hot autoclave process is adopted to form the carbon fiber composite material, wherein the molding temperature is 280℃, the pressure is 1.0 MPa, and the curing time is 6h, and the carbon fiber composite material with a thickness of about 1.5mm is obtained.

[0073] 2. Comparative Example

[0074] Comparative Example 1

[0075] The difference between Comparative Example 1 and Example 1 is that no ethylene-tetrafluoroethylene copolymer film is applied, and the rest is the same as Example 1.

[0076] Comparative Example 2

[0077] The difference between Comparative Example 2 and Example 1 is that nano-hydroxyapatite is used instead of modified nano-hydroxyapatite, and the rest is the same as Example 1.

[0078] Comparative Example 3

[0079] The difference between Comparative Example 3 and Example 1 is that carboxymethyl cellulose and nano-hydroxyapatite are used instead of modified nano-hydroxyapatite, the mass ratio of carboxymethyl cellulose to nano-hydroxyapatite is 1:2, and the rest is the same as Example 1.

[0080] Comparative Example 4

[0081] The difference between Comparative Example 4 and Example 5 is that no ethylene-tetrafluoroethylene copolymer film is applied, and the rest is the same as Example 5.

[0082] Comparative Example 5

[0083] The difference between Comparative Example 5 and Example 6 is that no ethylene-tetrafluoroethylene copolymer film is applied, and the rest is the same as Example 6.

[0084] 3. Test examples

[0085] Test Example 1

[0086] The contact angle of the ethylene-tetrafluoroethylene copolymer film obtained in Example 1, which was subjected to vacuum plasma grafting treatment on both sides, was measured by a contact angle tester. The results are as follows: Figure 1 The microstructure of the ethylene-tetrafluoroethylene copolymer film was characterized by scanning electron microscopy. Figure 2 shown.

[0087] Figure 1 This is a contact angle result diagram of the ethylene-tetrafluoroethylene copolymer film obtained in Example 1, both sides of which were subjected to vacuum plasma grafting treatment. Figure 1 It is known that the contact angle of the untreated ethylene-tetrafluoroethylene copolymer film (original) is 104°, and the contact angle of the ethylene-tetrafluoroethylene copolymer film subjected to vacuum plasma grafting treatment on both sides (after treatment) is 67°.

[0088] Figure 2 The microstructure of ethylene-tetrafluoroethylene copolymer films treated differently. Figure 2 Figure (a) is the microstructure of the untreated ethylene-tetrafluoroethylene copolymer film. Figure 2 Figure (b) is a microstructure diagram of the ethylene-tetrafluoroethylene copolymer film of Example 1, both sides of which were subjected to vacuum plasma grafting treatment. Figure 2 The above results show that the hydrophilicity of the ethylene-tetrafluoroethylene copolymer film after vacuum plasma grafting has changed, but the microstructure has no obvious change.

[0089] Test Example 2

[0090] The carbon fiber composite materials obtained in Examples 1-6 and Comparative Examples 1-5 were processed into discs with a diameter of 80 mm. The leakage rates of helium at different pressures were tested in a liquid nitrogen environment. The results are shown in Table 1.

[0091] Table 1

[0092]

[0093] It can be seen from Table 1 that the carbon fiber composite material obtained by the present invention has a thickness of less than 3 mm and a leakage rate of less than 10 at 3 MPa. -5 Pa·m 3 / s.

[0094] Compared with the embodiment, the carbon fiber composite material of the comparative example has no anti-seepage film and no modified nano-hydroxyapatite added, and the leakage rate is significantly increased. It can be seen that the carbon fiber composite material obtained by the present invention can effectively prevent the occurrence of leakage.

[0095] The above are only preferred embodiments of the present invention, and are not limited to the above examples. For those skilled in the art, various changes and variations are possible under the principle of the present invention. Any modifications and improvements made should be considered within the scope of protection of the present invention.

Claims

1. A carbon fiber composite material for preventing low-temperature medium leakage, characterized in that: The carbon fiber composite material comprises carbon fiber, resin matrix, modified nano-hydroxyapatite and anti-seepage film; the mass percentage of the carbon fiber is 45-69%, the mass percentage of the resin matrix is ​​26-37%, the mass percentage of the anti-seepage film is 2-10%, and the modified nano-hydroxyapatite is the balance; The preparation method of the modified nano-hydroxyapatite is as follows: adding nano-hydroxyapatite, decanoic acid and carboxymethyl cellulose into a solvent for reaction to obtain; Both sides of the anti-seepage film are subjected to vacuum plasma grafting treatment; the material of the anti-seepage film is ethylene-tetrafluoroethylene copolymer.

2. The carbon fiber composite material for preventing low-temperature medium leakage according to claim 1, characterized in that: The mass ratio of the carboxymethyl cellulose, nano-hydroxyapatite and capric acid is 1: (0.5-1): (1.5-3); the solvent is an ethanol aqueous solution; the mass concentration of ethanol in the ethanol aqueous solution is 65-75wt%; the reaction temperature is 95-105°C, and the reaction time is 4-5h.

3. The carbon fiber composite material for preventing low-temperature medium leakage according to claim 1, characterized in that: The resin matrix is ​​a thermoplastic resin matrix or a thermosetting resin matrix; the thermoplastic resin matrix is ​​selected from one of polyamide, polycarbonate, polyurethane, polyethylene terephthalate, polyphenylene sulfide, polysulfone, polyimide, polyarylate, liquid crystal polymer, polyetheretherketone, polyetherketoneketone, polytetrafluoroethylene, polyvinylidene fluoride, and polychlorotrifluoroethylene; the thermosetting resin matrix is ​​selected from one of epoxy resin, polyimide, phenolic resin, unsaturated polyester resin, amino resin, furan resin, silicone resin, polyurethane, and vinyl resin.

4. The carbon fiber composite material for preventing low-temperature medium leakage according to claim 1, characterized in that: The cryogenic medium is one of liquid oxygen, liquid hydrogen, liquid natural gas, liquid petroleum gas, and liquid nitrogen.

5. The method for preparing the carbon fiber composite material for preventing low-temperature medium leakage according to any one of claims 1 to 4, characterized in that: The following steps are involved: Method (1): According to the mass percentage of each component in the carbon fiber composite material, carbon fiber, resin matrix, and modified nano-hydroxyapatite are prepared into prepreg, and then the surface-treated anti-seepage film is spread between the layers and / or on the surface of the prepreg layer, and the carbon fiber composite material for preventing low-temperature medium leakage is prepared by a composite material molding process; Method (2): According to the mass percentage of each component in the carbon fiber composite material, the resin matrix and the modified nano-hydroxyapatite are uniformly mixed to obtain a mixture of the two; then the surface-treated anti-seepage film, the resin matrix and the mixture of the modified nano-hydroxyapatite are respectively spread on the surface layer and / or between the layers of the carbon fiber layer, and then a composite material molding process is used to prepare the carbon fiber composite material for preventing low-temperature medium leakage; Method (3): According to the mass percentage of each component in the carbon fiber composite material, the surface treated anti-seepage film is spread on the surface and / or between the layers of the carbon fiber layer, the resin matrix and the modified nano-hydroxyapatite are evenly mixed and then poured into the interior of the carbon fiber through a vacuum assisted infusion process or a resin transfer molding process, and heated and cured.

6. The method for preparing a carbon fiber composite material for preventing low-temperature medium leakage according to claim 5, characterized in that: The molding process described in method (1) and method (2) is a molding process or an autoclave process.

7. The method for preparing a carbon fiber composite material for preventing low-temperature medium leakage according to claim 5, characterized in that: The resin matrix described in method (2) is a thermoplastic resin matrix; the resin matrix described in method (3) is a thermosetting resin matrix.

8. The use of the carbon fiber composite material for preventing low-temperature medium leakage according to any one of claims 1 to 4, characterized in that: Application in the preparation of aerospace propellant tanks.

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