Radiation protection composite material and structure for medium-orbit satellite charged particle radiation protection

Abstract

The invention provides a radiation protection composite material and a structure for medium-orbit satellite charged particle radiation protection. The radiation protection composite material is prepared from the following components in parts by weight: 1 to 100 parts of polymer matrix, 1 to 60 parts of copper-coated boron nitride BN-Cu particles, 0.1 to 1 part of antioxidant and 0.1 to 1 part of coupling agent. The structure for medium-orbit satellite charged particle radiation protection comprises an upper packaging layer, an upper adhesive layer, a radiation protection composite material layer prepared from a radiation protection composite material, a lower adhesive layer and a lower packaging layer, the upper packaging layer and the lower packaging layer are respectively glued with the radiation protection composite material layer through the upper glue layer and the lower glue layer. According to the radiation protection structure provided by the invention, aiming at the medium orbit environment of satellite operation, the problems of redundancy and the like caused by degradation of the composite material layer due to total dose damage of the medium orbit environment can be effectively avoided, and the use safety of the radiation protection structure in a spacecraft is greatly improved.

Description

Technical Field

[0001] This invention relates to the field of satellite radiation protection technology, specifically to a radiation protection composite material and a structure for protecting against charged particle radiation from medium-orbit satellites. Background Technology

[0002] With the development of my country's space technology, satellite operating environments are expanding to various orbits to achieve different functions. Different orbits expose satellites to different radiation effects. A low-inclination circular orbit at 7500 km altitude is located within the inner zone of the Earth's radiation belts, outside the magnetosphere, ionosphere, and thermosphere, and outside the center of the proton radiation belt and the center of the electron radiation belt trough. Its electron radiation environment is better than MEO and GEO, but its proton environment is more severe than LEO, MEO, and GEO, resulting in a very high total dose intensity. Studies show that a satellite in this orbit with a typical design life of 8 years will accumulate a total dose of 1.13E+09 rad(Si). This will cause severe degradation of spacecraft materials, deterioration of electronic device performance, seriously affecting satellite lifespan and reliability, and even causing satellite failure.

[0003] Currently, spacecraft use additional high atomic number metals (tantalum, lead, etc.) or thickened aluminum star structures to shield charged particles. This shielding method is heavy, has poor compatibility with devices, and poses a high risk of generating secondary particles. Using polymer-based radiation protection materials alone has low total dose tolerance and can produce excess material due to damage, affecting other satellite functions. Summary of the Invention

[0004] This invention addresses the problems of poor performance and high weight of existing radiation protection technologies for medium-Earth orbit (MEO) satellites, as well as the severe total dose damage caused by polymer-based radiation protection materials. It provides a radiation protection composite material and a structure for charged particle radiation protection in MEO satellites. The radiation protection structure provided by this invention, specifically designed for the MEO operating environment, effectively avoids the degradation of the composite material layer and the generation of excess material caused by total dose damage in the MEO environment, significantly improving the safety of the radiation protection structure for use in spacecraft.

[0005] <First Aspect>

[0006] A radiation protection composite material comprises the following components in parts by weight:

[0007] 1 to 100 parts of polymer matrix

[0008] 1 to 60 parts of copper-coated boron nitride (BN@Cu) particles

[0009] Antioxidant 0.1 to 1 part

[0010] 0.1 to 1 part of coupling agent.

[0011] Preferably, the radiation protection composite material comprises the following components in parts by weight:

[0012]

[0013] The polymer matrix includes one or more of polyethylene, polypropylene, ethylene-propylene copolymer, and polyetheretherketone.

[0014] The method for preparing the copper-coated boron nitride (BN@Cu) particles includes the following steps:

[0015] 1) Disperse boron nitride powder in an aqueous solution of copper salt to form a suspension;

[0016] 2) Add phenylenediamine to the suspension from step 1) and allow the reaction to proceed;

[0017] 3) Add an alkaline adjuster to adjust the pH of the system to 9-11, and then add hydrazine hydrate solution dropwise;

[0018] 4) Add polyvinylpyrrolidone and continue stirring to react;

[0019] 5) The obtained suspension is filtered, washed, and vacuum dried to obtain the copper-coated boron nitride (BN@Cu) particles.

[0020] The copper-coated boron nitride (BN@Cu) particles prepared by the above method have a copper loading of 10-30 wt%, with copper elements uniformly loaded on the surface of boron nitride in the form of a coating layer.

[0021] In 1), the copper salt includes at least one of copper chloride, copper sulfate, and copper nitrate.

[0022] In 1), the boron nitride is a nanoparticle with a particle size of 20-100 nm.

[0023] Preferably, the copper salt is copper chloride. The concentration of the copper chloride aqueous solution is 0.05-0.2 mol / L. The mass-to-volume ratio of boron nitride to copper chloride is 1 g: 20-40 mL.

[0024] The mass ratio of phenylenediamine to boron nitride is (0.7-0.8):1.

[0025] In step 2), the reaction conditions are: react at 60-80℃ for 1-3 hours.

[0026] In step 3), the alkalinity regulator is ammonia water, the concentration of hydrazine hydrate is 3-5 mol / L, and the addition amount is 1.5-2.0 mL of hydrazine hydrate per gram of boron nitride.

[0027] The mass ratio of polyvinylpyrrolidone to boron nitride is (3.0-3.2):1.

[0028] In step (4), the reaction time is 1-3 hours at 60-80℃. In step (5), the vacuum drying temperature is 60-80℃.

[0029] <Second aspect>

[0030] The radiation protection composite material layer prepared from the above-described radiation protection composite material is obtained by a method comprising the following steps:

[0031] S1. Weigh the polymer matrix, BN@Cu particles, antioxidant 1010, and coupling agent according to the weight parts;

[0032] S2. The above materials are mixed evenly through an extruder at a temperature of 180℃~250℃ and extruded into a film to obtain the radiation protection composite material.

[0033] The thickness of the radiation protection composite material layer is 50μm to 1000μm, and multiple layers can be stacked as needed.

[0034] <Third aspect>

[0035] A structure for charged particle radiation protection for medium-Earth orbit satellites includes an upper encapsulation layer, an upper adhesive layer, a radiation protection composite material layer as described above, a lower adhesive layer, and a lower encapsulation layer; the upper encapsulation layer is bonded to the upper surface of the radiation protection composite material layer via the upper adhesive layer; the lower encapsulation layer is bonded to the lower surface of the radiation protection composite material layer via the lower adhesive layer.

[0036] The materials of the upper and lower adhesive layers are independently selected from one or more of epoxy resin adhesives, acrylic adhesives, silicone adhesives, and polyurethane adhesives; among which, when epoxy resin adhesives are used, radiation-resistant epoxy thermosetting adhesive films are preferred.

[0037] The thickness of the upper and lower adhesive layers is independently between 10 μm and 100 μm.

[0038] The materials of the upper and lower encapsulation layers are independently selected from one of the following: polyimide film, polyester film, polyetheretherketone film, and fluoropolymer film.

[0039] The thickness of the upper encapsulation layer and the lower encapsulation layer are independently 5μm to 50μm.

[0040] The method for preparing the structure for charged particle radiation protection of medium-orbit satellites includes the following steps: stacking an upper encapsulation layer, an upper adhesive layer, a radiation protection composite material layer, a lower adhesive layer, and a lower encapsulation layer sequentially from top to bottom, and encapsulating them by vacuum hot pressing, wherein: the heating temperature is 60℃~180℃, the heating time is 30s~180s, and the vacuum degree is -0.01MPa~-0.1MPa. After encapsulation, a curing treatment is performed, with a curing time of 3-7 days.

[0041] Compared with the prior art, the present invention has the following advantages:

[0042] 1. The radiation protection composite material layer provided by this invention uses a polymer as the radiation protection material matrix, and the added radiation protection reinforcing material is BN@Cu particles. Its structure is a core-shell nanomaterial, and its main function is to modify the thermal conductivity of the polymer by utilizing the high thermal conductivity of BN and Cu. Through multiple experiments, it was found that in the BN@Cu particles, the surface Cu layer facilitates the reflection and scattering of high-energy electrons, greatly improving the shielding ability of the protective film against electrons; the inner layer of plate-like BN has a low atomic number, which can effectively absorb high-energy protons, and can also absorb secondary photons generated by bremsstrahlung during collisions of high-energy electrons; at the same time, the interface structure formed by Cu and BN facilitates multiple reflections and absorptions of high-energy particles during transport, significantly improving protection efficiency and greatly reducing density, effectively solving the drawback of the heavy weight of aluminum protective layers and expanding its application range.

[0043] 2. The radiation protection structure provided by this invention is designed for the medium-Earth orbit environment of satellites. By encapsulating the radiation protection composite material layer with polyimide, it can effectively avoid the degradation of the composite material layer caused by total dose damage in the medium-Earth orbit environment, resulting in the generation of excess substances. This significantly improves the safety of the radiation protection structure in spacecraft applications.

[0044] 3. The present invention uses BN@Cu particles because, on the one hand, BN@Cu particles improve the blocking ability of high-energy protons and electrons of the matrix polymer, and on the other hand, they have a high thermal conductivity and thermal emissivity, which can improve the thermal conductivity and thermal emissivity of the composite material. When used in space, this is beneficial to the heat transfer and radiative heat dissipation of spacecraft electronic devices.

[0045] 4. The composite material provided by this invention has an electron protection efficiency that is 1.74 to 2.65 times higher than that of pure aluminum, and a proton protection efficiency that is 1.65 to 2.14 times higher than that of pure aluminum.

[0046] 5. The composite material provided by this invention has a surface resistivity of less than 10. 9 It has an antistatic effect. Detailed Implementation

[0047] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0048] In the following embodiments and comparative examples:

[0049]

[0050] Preparation Example 1: Preparation of BN@Cu Particles

[0051] BN@Cu particles are prepared by a coating method that induces copper ion deposition through boron nitride surface activation grafting. Specifically, copper chloride (CuCl2) is used as the copper source, and the mixture is prepared under alkaline conditions by treatment with phenylenediamine (DBA), followed by a heated co-bath with hydrazine hydrate and polyvinylpyrrolidone (PVP). The specific experimental procedure is as follows:

[0052] 20 g of boron nitride (BN, 50 nm particle size) was added to 625 ml of 0.1 mol / L CuCl2 aqueous solution to form a suspension. 15.03 g of phenylenediamine (DAB) was added to this suspension, and after stirring thoroughly, the mixture was reacted at 70 °C for 2 hours. Ammonia was added to adjust the pH to 10, followed by the slow addition of 32.5 ml of 4 mol / L hydrazine hydrate, and then 63.7 g of polyvinylpyrrolidone (PVP). Stirring continued for 2 hours to obtain a purple suspension. After filtration, the suspension was washed three times with deionized water and finally dried under vacuum at 70 °C to obtain BN@Cu particles with a 20% copper loading.

[0053] Preparation Examples 2-3

[0054] Preparation Examples 2-3 involve a radiation protection composite material layer and its preparation method; the components and amounts of the radiation protection composite material layer are shown in Table 1.

[0055] Table 1. Components and dosage of the radiation protection composite material layer in the embodiments (unit: parts by weight)

[0056]

[0057] The preparation method of the radiation protection composite material layer described in Examples 1-2 includes the following steps:

[0058] S1. Weigh the polymer, BN@Cu particles, antioxidant, and coupling agent according to the weight parts in Table 1.

[0059] S2. The above raw materials are mixed evenly using an extruder at a temperature of 180℃~250℃, and then extruded into a film to obtain the radiation protection composite material layer; wherein:

[0060] The thickness of the radiation protection composite material layer prepared by the formulation in Preparation Example 2 is 500 μm ± 50 μm;

[0061] The thickness of the radiation protection composite material layer prepared by the formulation of Preparation Example 3 is 500 μm ± 50 μm.

[0062] Comparative Preparation Example 1

[0063] The difference between Comparative Preparation Example 1 and Preparation Example 2 is that BN@Cu particles with a 10% copper loading were used, and the thickness of the radiation protection composite material layer was 500 μm ± 50 μm.

[0064] Preparation method of 10% copper-loaded BN@Cu particles: 20g of boron nitride (BN, particle size 50nm) was added to 312.5ml of 0.1mol / L CuCl2 aqueous solution to form a suspension; 7.515g of phenylenediamine (DAB) was added to the suspension, stirred evenly, and reacted at 70℃ for 2 hours. Ammonia was added to adjust the pH to 10, and then 16.25ml of 4mol / L hydrazine hydrate was slowly added dropwise, followed by 31.85g of polyvinylpyrrolidone (PVP). Stirring was continued for 2 hours to obtain a purple suspension; after filtration, the suspension was washed three times with deionized water, and finally dried under vacuum at 70℃ to obtain 10% copper-loaded BN@Cu particles.

[0065] Comparative Preparation Example 2

[0066] The difference between Comparative Preparation Example 1 and Preparation Example 2 is that BN@Cu particles were replaced with BN (particle size 50 nm); the thickness of the obtained radiation protection composite material layer was 500 μm ± 50 μm.

[0067] Comparative preparation example 3

[0068] The difference between Comparative Preparation Example 1 and Preparation Example 2 is that the ethylene-propylene copolymer was replaced with an equal amount of polyethylene; the thickness of the obtained radiation protection composite material layer was 500 μm ± 50 μm.

[0069] Comparative preparation example 4

[0070] The difference between Comparative Preparation Example 1 and Preparation Example 2 is that polyethylene was replaced with an equal amount of ethylene-propylene copolymer; the thickness of the obtained radiation protection composite material layer was 500 μm ± 50 μm.

[0071] Example 1

[0072] This embodiment provides a charged particle radiation protection structure for medium-orbit satellites and its preparation method.

[0073] The structure for protection against charged particle radiation for medium-orbit satellites includes an upper encapsulation layer, an upper adhesive layer, a radiation protection composite material layer, a lower adhesive layer, and a lower encapsulation layer; the upper encapsulation layer is bonded to the upper surface of the radiation protection composite material layer via the upper adhesive layer; the lower encapsulation layer is bonded to the lower surface of the radiation protection composite material layer via the lower adhesive layer.

[0074] The method for fabricating a charged particle radiation protection structure for a medium-orbit satellite includes the following steps.

[0075] S1: Cut the upper encapsulation layer, upper adhesive layer, radiation protection composite material layer (Preparation Example 2), lower adhesive layer, and lower encapsulation layer separately. When cutting, the radiation protection composite material layer should be smaller than the upper encapsulation layer, upper adhesive layer, lower adhesive layer, and lower encapsulation layer to ensure that the upper encapsulation layer and the lower encapsulation layer are bonded by the adhesive layer at the edge. The bonding size is cut as needed.

[0076] S2: Stack the upper encapsulation layer, upper adhesive layer, radiation protection composite material layer, lower adhesive layer, and lower encapsulation layer in sequence into a vacuum press with a preheating temperature of 80°C.

[0077] S3: Vacuum degree -0.04MPa, heat for 50s to complete vacuum sealing, and immediately remove the sample;

[0078] S4: After the sample is removed, cure at room temperature for 3 days.

[0079] Example 2

[0080] This embodiment provides a charged particle radiation protection structure for a medium-orbit satellite and its preparation method.

[0081] The structure for protection against charged particle radiation for medium-Earth orbit satellites is the same as in Example 1, and the preparation method includes the following steps:

[0082] S1: Cut the upper encapsulation layer, upper adhesive layer, radiation protection composite material layer (preparation example 3), lower adhesive layer, and lower encapsulation layer separately. When cutting, the radiation protection composite material layer should be smaller than the upper encapsulation layer, upper adhesive layer, lower adhesive layer, and lower encapsulation layer to ensure that the upper encapsulation layer and the lower encapsulation layer are bonded by the adhesive layer at the edge. The bonding size is cut as needed.

[0083] S2: Stack the upper encapsulation layer, upper adhesive layer, radiation protection composite material layer, lower adhesive layer, and lower encapsulation layer in sequence into a vacuum press with a preheating temperature of 80°C.

[0084] S3: Vacuum degree -0.04MPa, heat for 50s to complete vacuum sealing, and immediately remove the sample;

[0085] S4: After the sample is removed, cure at room temperature for 3 days.

[0086] Comparative Example 1

[0087] The difference between this comparative example and Example 1 is that the radiation protection composite material layer uses the material prepared in Comparative Preparation Example 1.

[0088] Comparative Example 2

[0089] The difference between this comparative example and Example 1 is that the radiation protection composite material layer uses the material prepared in Comparative Preparation Example 2.

[0090] Comparative Example 3

[0091] The difference between this comparative example and Example 1 is that the radiation protection composite material layer uses the material prepared in Comparative Preparation Example 3.

[0092] Comparative Example 4

[0093] The difference between this comparative example and Example 1 is that the radiation protection composite material layer uses the material prepared in Comparative Preparation Example 4.

[0094] Performance Test Example 1

[0095] 1. Electron irradiation electron absorbed dose tests were conducted on the samples prepared in Examples 1-2, Comparative Examples 1-4, and existing pure aluminum (control group). The test methods are as follows:

[0096] Electron radiation protection performance test: An electron energy spectrum with approximate high orbit is generated using a radiation source. Dosimeter #1 is placed in front of the sample to record the absorbed dose D1 under unshielded conditions, and dosimeter #2 is placed behind the sample to record the absorbed dose D2 of electrons penetrating the sample. The electron protection efficiency η of the sample under approximate energy spectrum incident radiation is calculated using the following formula. e ,unit"%":

[0097]

[0098] Among them, particle energy: energy spectrum distribution, up to 2.28 MeV; beam current intensity: 1–10 pA / cm 2 .

[0099] The test results are shown in Table 2.

[0100] 2. Proton irradiation protection tests were conducted on the films prepared in Examples 1-2, Comparative Examples 1-4, and existing pure aluminum (control group); Test methods:

[0101] The method for proton irradiation protection testing involves irradiating the sample with a 10 MeV monoenergetic proton beam generated by a particle accelerator. Since the proton energy diverges after penetrating the sample, a proton energy detector is used to record the energy values ​​of the protons after they have passed through the sample, ultimately forming a transmission energy spectrum. The energy value E corresponding to the peak value of the transmission energy spectrum is then selected. p The energy of the transmitted proton is characterized by (which is also the average energy of the transmitted proton), where E0 is the energy of the monoenergetic proton used. The proton protection efficiency η of the sample under approximate energy spectrum incident light is calculated by the following formula. p ,unit"%":

[0102]

[0103] The test results are shown in Table 2.

[0104] 3. For the films of Examples 1-2 and Comparative Examples 1-4, the surface resistivity was tested according to GB / T 31838.3-2019 Dielectric and resistive properties of solid insulating materials Part 3: Resistive properties (DC method) Surface resistance and surface resistivity. The test results are shown in Table 2.

[0105] Table 2

[0106]

[0107] Performance Test Example 2

[0108] The thin film prepared in Preparation Example 1 and the sample prepared in Example 1 were simultaneously placed in a proton-electron irradiation device to verify their radiation resistance. The total irradiation dose was 1 × 10⁻⁶. 10 The irradiation was measured in rad, and the materials before and after irradiation were tested according to GB / T1040.3-2006 Determination of tensile properties of plastics Part 3: Test conditions for films and sheets. The changes in mechanical properties were compared, and the test results are shown in Table 3.

[0109] Table 3

[0110] name Preparation Example 1 Example 1 Tensile strength before irradiation 16.5MPa 30.5MPa After tensile strength irradiation 3.2MPa 18.6MPa

[0111] This invention addresses the problems of poor performance and high weight of existing radiation protection technologies for medium-Earth orbit satellites, as well as the severe total dose damage caused by polymer-based radiation protection materials. It provides a structure and manufacturing method for charged particle radiation protection of medium-Earth orbit satellites. This not only achieves lightweight radiation protection materials but also ensures that the materials do not generate excess material due to total dose damage under the high radiation dose environment of medium-Earth orbit. It can be used in various locations inside or outside the satellite structure, and its inherent conductivity prevents static electricity accumulation, thus expanding the application scope of radiation protection films and overcoming the limitations of existing technologies.

[0112] In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicating the orientation or positional relationship, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0113] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A radiation protection composite material, characterized in that, The components include the following parts by weight:

2. The radiation protection composite material according to claim 1, characterized in that, The polymer matrix includes one or more of polyethylene, polypropylene, ethylene-propylene copolymer, and polyetheretherketone.

3. The radiation protection composite material according to claim 1, characterized in that, The preparation method of the copper-coated boron nitride (BN@Cu) particles includes the following steps: 1) Disperse boron nitride powder in an aqueous solution of copper salt to form a suspension; 2) Add phenylenediamine to the suspension from step 1) and allow the reaction to proceed; 3) Add an alkaline adjuster to adjust the pH of the system to 9-11, and then add hydrazine hydrate solution dropwise; 4) Add polyvinylpyrrolidone and continue stirring to react; 5) The obtained suspension is filtered, washed, and vacuum dried to obtain the copper-coated boron nitride (BN@Cu) particles.

4. The radiation protection composite material according to claim 3, characterized in that, In 1), the copper salt includes at least one of copper chloride, copper sulfate, and copper nitrate; And / or, in 1), the boron nitride is a nanoparticle powder with a particle size of 20-100 nm; And / or, in 2), the reaction conditions are: react at 60-80℃ for 1-3 hours; And / or, in 3), the alkaline regulator is ammonia water, the concentration of hydrazine hydrate is 3-5 mol / L, and the addition amount is 1.5-2.0 mL of hydrazine hydrate per gram of boron nitride.

5. A radiation protection composite material layer prepared from the radiation protection composite material according to any one of claims 1-4, characterized in that, The radiation protection composite material layer is prepared by a method comprising the following steps: S1. Weigh the polymer matrix, copper-coated boron nitride (BN@Cu) particles, antioxidant, and coupling agent according to the weight proportions. S2. The above materials are mixed evenly through an extruder at a temperature of 180℃~250℃ and extruded into a film to obtain the radiation protection composite material layer.

6. A structure for protection against charged particle radiation in medium-Earth orbit satellites, characterized in that, It includes an upper encapsulation layer, an upper adhesive layer, a radiation protection composite material layer as described in claim 5, a lower adhesive layer, and a lower encapsulation layer; the upper encapsulation layer is bonded to the upper surface of the radiation protection composite material layer through the upper adhesive layer; the lower encapsulation layer is bonded to the lower surface of the radiation protection composite material layer through the lower adhesive layer.

7. The structure for charged particle radiation protection of medium-orbit satellites according to claim 6, characterized in that, The materials of the upper and lower adhesive layers are independently selected from one or more of epoxy resin adhesives, acrylic adhesives, silicone adhesives, and polyurethane adhesives; And / or, the thickness of the upper adhesive layer and the lower adhesive layer is independently from 10 μm to 100 μm.

8. The structure for charged particle radiation protection of medium-orbit satellites according to claim 6, characterized in that, The materials of the upper encapsulation layer and the lower encapsulation layer are independently selected from one of polyimide film, polyester film, polyetheretherketone film, and fluoropolymer film; And / or, the thickness of the upper encapsulation layer and the lower encapsulation layer is independently 5μm to 50μm.

9. A method for preparing a structure for charged particle radiation protection for medium-orbit satellites as described in any one of claims 6-8, characterized in that, The process includes the following steps: stacking the upper encapsulation layer, upper adhesive layer, radiation protection composite material layer, lower adhesive layer, and lower encapsulation layer sequentially from top to bottom, and completing the encapsulation through vacuum hot pressing.

10. The preparation method according to claim 9, characterized in that, Vacuum hot pressing conditions: temperature 60℃~180℃, heating time 30s~180s, vacuum degree -0.01MPa~-0.1MPa, after encapsulation, curing treatment is performed, curing time 3-7 days.

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