A protective composite material, its preparation method and application

Abstract

This invention discloses a protective composite material, its preparation method, and its application. The preparation method includes: modifying a two-dimensional lightweight material to obtain a modified two-dimensional lightweight material; and self-assembling the modified two-dimensional lightweight material with a two-dimensional heavy material, followed by annealing to obtain the protective composite material; wherein the modified two-dimensional lightweight material and the two-dimensional heavy material have opposite surface charges. This invention, through the microscopic composite and macroscopic assembly of two-dimensional lightweight and two-dimensional heavy materials, prepares a protective material that can significantly increase the interaction area between the shielding components and radiation, significantly reduce the interparticle porosity of the protective material, improve the utilization rate of the protective material, and enhance the interfacial forces between heterogeneous materials.

Description

Technical Field

[0001] This invention belongs to the field of new materials technology, specifically relating to a protective composite material, its preparation method, and its application. Background Technology

[0002] Nuclear protection plays a crucial role in the utilization and development of nuclear energy. Nuclear energy is one of humanity's most promising future energy sources, with approximately 16% of the world's electricity produced by nuclear reactors, and over 40% of the energy production in nine countries derived from nuclear power. However, nuclear radiation is generated in areas such as nuclear material mining and processing, spent fuel reprocessing, and nuclear emergency response, releasing charged particles such as alpha and beta rays, as well as ionizing radiation including X-rays, gamma rays, and neutron radiation, all of which pose significant risks to human health and the environment. Because d-rays and beta rays have high mass and low penetrating power, ordinary clothing is sufficient to block them, thus eliminating the need for specialized protection. Therefore, the primary targets of nuclear radiation are X-rays, gamma rays, and neutrons, and researching materials with comprehensive neutron and X / γ-ray shielding capabilities has become a current trend in nuclear radiation shielding research. Based on shielding type, nuclear radiation shielding materials can be divided into neutron shielding materials and X / γ-ray shielding materials. On the one hand, since the mass of a neutron is similar to that of a proton, polymers with high hydrogen content, such as polyethylene and polypropylene, can slow down fast neutrons. Absorption of slow neutrons requires compounds containing elements such as lithium and boron, including lithium fluoride, lithium bromide, boric acid, and boron carbide (B4C). Among these, B4C is considered the mainstream neutron absorbing material due to its excellent mechanical properties, thermal conductivity, and neutron absorption capacity. On the other hand, X-ray / gamma-ray shielding requires the photoelectric effect generated by the absorption at the K-layer boundary of heavy elements and the photon interaction with high-energy rays. Lead is the most widely used radiation protection material, but lead pollution has prompted the exploration of lead-free shielding technologies to become a widely studied research direction in recent years. In contrast, tungsten has a larger atomic number, high density, high strength, and high temperature resistance, and also possesses excellent X-ray / gamma-ray absorption capacity, making it an ideal alternative to lead.

[0003] To meet the diverse needs of human nuclear protection in various situations, nuclear protective clothing requires integrated protection against both neutrons and X / γ rays. Nuclear radiation protection materials have evolved from traditional single-component materials to the current composite material stage. The key component in composite materials is the shielding functional particles. The uniformity and distribution characteristics of different types of functional particles within the matrix affect the final shielding effect of the composite material. Under the same content conditions, the more uniform the dispersion of functional particles, the smaller the protective defects and the better the shielding performance. Smaller particle sizes result in larger specific surface areas, which also increase the probability of interaction with radiation and improve the shielding effect. Therefore, the low-dimensional controllable preparation and microscopic composite of different types of shielding functional materials are crucial for achieving efficient comprehensive protection. Furthermore, with millions of radiation environment workers in China, overly bulky individual radiation protection equipment would severely impact their work efficiency. Therefore, the development of lightweight, flexible, and high-performance wearable radiation protection products is imperative. Therefore, lightweight, soft, non-toxic, and environmentally friendly are also important features emphasized in the new generation of nuclear protective clothing. It is necessary to improve the utilization rate and bonding degree of each shielding component by optimizing the composite structure of materials, so as to reduce the amount of shielding material used and improve mechanical stability. Summary of the Invention

[0004] The main objective of this invention is to provide a protective composite material, its preparation method, and its application, in order to overcome the shortcomings of the prior art.

[0005] To achieve the aforementioned objectives, the technical solution adopted by this invention includes:

[0006] This invention provides a method for preparing a protective composite material, comprising:

[0007] Modified two-dimensional lightweight materials are prepared by modifying them.

[0008] Furthermore, the modified two-dimensional lightweight material and the two-dimensional heavy material are self-assembled and then annealed to obtain a protective composite material; wherein the modified two-dimensional lightweight material and the two-dimensional heavy material have opposite charges on their surfaces.

[0009] This invention also provides a protective composite material prepared by the aforementioned method.

[0010] This invention also provides the use of the aforementioned protective composite material in the preparation of nuclear radiation protective equipment.

[0011] Compared with the prior art, the beneficial effects of the present invention are as follows: the protective material is prepared by microscopic composite and macroscopic assembly of two-dimensional lightweight materials and two-dimensional heavy materials, which can greatly increase the interaction area between the shielding components and the radiation, significantly reduce the gap between particles of the protective material, improve the utilization rate of the protective material and enhance the interaction force of the heterogeneous interface. It is a successful way to obtain lightweight and high-strength composite materials and provide an effective method for achieving efficient comprehensive radiation protection capabilities. Attached Figure Description

[0012] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0013] Figure 1 This is an AFM morphology image of the two-dimensional lightweight material prepared in Example 1 of this invention;

[0014] Figure 2 This is an AFM morphology image of the two-dimensional heavy material prepared in Example 1 of this invention;

[0015] Figure 3 This is the XRD pattern of the protective composite material prepared in Example 1 of this invention;

[0016] Figure 4 This is a schematic diagram of the protective composite material in a typical embodiment of the present invention;

[0017] Figure 5 This is a schematic diagram illustrating the protection of nanoparticles in Comparative Example 1 of the present invention. Detailed Implementation

[0018] In view of the deficiencies of the prior art, the inventors of this invention, through long-term research and extensive practice, have proposed the technical solution of this invention. By controllably preparing two-dimensional lightweight material nanosheets (e.g., h-BN nanosheets) and two-dimensional heavy material nanosheets (e.g., WO3 nanosheets) in a two-dimensional manner, as well as the corresponding microscopic composite and macroscopic assembly, the interaction area between the shielding components and radiation can be greatly increased, the interparticle voids of the protective material can be significantly reduced, and the utilization rate of the protective material can be improved, thus providing an effective method for achieving efficient comprehensive radiation protection capabilities.

[0019] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Specifically, as one aspect of the technical solution of this invention, a method for preparing a protective composite material includes:

[0021] Modified two-dimensional lightweight materials are prepared by modifying them.

[0022] Furthermore, the modified two-dimensional lightweight material and the two-dimensional heavy material are self-assembled and then annealed to obtain a protective composite material; wherein the modified two-dimensional lightweight material and the two-dimensional heavy material have opposite charges on their surfaces.

[0023] In some preferred embodiments, the two-dimensional lightweight material is a two-dimensional lightweight nanosheet, the thickness of which is 3-10 nm and the size is 1-10 μm.

[0024] In some preferred embodiments, the two-dimensional lightweight material nanosheets are prepared by liquid phase exfoliation.

[0025] Furthermore, the ultrasonic power used in the liquid phase stripping method is 60-100W, and the ultrasonic time is 2-4h.

[0026] Furthermore, the ultrasonic power used in the liquid phase stripping method is 100W, but it can be, but is not limited to, 60W, 70W, 80W, 90W, 100W, etc.

[0027] Furthermore, the ultrasonic time used in the liquid phase stripping method is 3 hours, but it can be, but is not limited to, 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, etc.

[0028] Furthermore, the collection method used in the liquid phase stripping method is centrifugation, and the centrifugation rate can be, but is not limited to, 5000 rpm, 6000 rpm, 7000 rpm, 8000 rpm, 9000 rpm, 10000 rpm, etc.

[0029] In some preferred embodiments, the two-dimensional lightweight material is a boron-based compound two-dimensional nanosheet.

[0030] In some preferred embodiments, the two-dimensional lightweight material includes any one or a combination of two or more of h-BN nanosheets, B4C nanosheets, g-C3N4 nanosheets, B2O3 nanosheets, and graphene oxide nanosheets, and is not limited thereto.

[0031] Furthermore, the two-dimensional lightweight material includes, but is not limited to, h-BN nanosheets.

[0032] In some preferred embodiments, the two-dimensional heavy material is a tungsten-based compound two-dimensional nanosheet.

[0033] In some preferred embodiments, the two-dimensional heavy material is a two-dimensional heavy material nanosheet, the thickness of which is 2-6 nm and the size is 0.1-1 μm.

[0034] In some preferred embodiments, the surface of the two-dimensional heavy material carries a negative charge.

[0035] In some preferred embodiments, the two-dimensional heavy material includes any one or a combination of two or more of WO3 nanosheets, MoO3 nanosheets, Bi2O3 nanosheets, WS2 nanosheets, and MoS2 nanosheets, and is not limited thereto.

[0036] Furthermore, the two-dimensional heavy material includes, but is not limited to, WO3 nanosheets.

[0037] In some preferred embodiments, the preparation method includes: modifying the two-dimensional lightweight material with a modifier to at least make the surface of the two-dimensional lightweight material positively charged, thereby obtaining the modified two-dimensional lightweight material.

[0038] Furthermore, the modifier includes, but is not limited to, any one or a combination of two of polydiallyldimethylammonium chloride (PDDA) and polyethyleneimine (PEI).

[0039] In some preferred embodiments, the mass ratio of the modified two-dimensional lightweight material to the two-dimensional heavy material is 3-5:4-6.

[0040] Furthermore, the mass ratio of the modified two-dimensional lightweight material to the two-dimensional heavy material can be any one of 3:5, 4:5, 5:5, or 5:6.

[0041] In some preferred embodiments, the preparation method includes: mixing the modified two-dimensional lightweight material and the two-dimensional heavy material at a stirring rate of 400-800 rpm to perform self-assembly.

[0042] Furthermore, the stirring rate is selected from any one of 400 rpm, 500 rpm, 600 rpm, 700 rpm, and 800 rpm.

[0043] In some preferred embodiments, the preparation method includes annealing the self-assembled product at 300–600°C for 0.5–2 h in a protective atmosphere.

[0044] Furthermore, the annealing temperature is 400℃, but the annealing temperature can be, but is not limited to, 300℃, 400℃, 500℃, 600℃, etc.

[0045] Furthermore, the annealing time is 1 hour, but the annealing time can be, but is not limited to, 0.5 hours, 1 hour, 1.5 hours, 2 hours, etc.

[0046] Furthermore, the protective atmosphere includes, but is not limited to, argon.

[0047] Furthermore, the rate at which the protective atmosphere is introduced is 100–300 sccm.

[0048] Furthermore, the rate at which the protective atmosphere is introduced is 200 sccm, and the ventilation rate may be, but is not limited to, 100 sccm, 150 sccm, 200 sccm, 250 sccm, 300 sccm, etc.

[0049] In some more specific embodiments, the preparation method of the protective composite material includes: using h-BN nanosheets as a two-dimensional lightweight material and synthesized WO3 nanosheets as a two-dimensional heavy material, modifying the h-BN nanosheets to make their surfaces positively charged, so that the surfaces of the two nanosheets have opposite charges, then mixing them, the positive and negative charges attract each other and assemble, centrifuging to collect, and then annealing the collected material at high temperature to make the lightweight and heavy materials more tightly assembled and bonded, thus obtaining the protective composite material.

[0050] Furthermore, the surface modifier of h-BN nanosheets is PDDA, which makes the surface of h-BN nanosheets positively charged.

[0051] Furthermore, the annealing temperature of the assembled product was 400℃, the atmosphere was Ar, the flow rate was 200 sccm, and the holding time was 1 h.

[0052] This invention assembles two-dimensional lightweight materials (such as boron-based compound h-BN nanosheets) with two-dimensional heavy materials (WO3 nanosheets), which can effectively improve the protective effect compared to the bulk materials of both. This method is universal, and the selected lightweight two-dimensional materials can be extended to graphene, boron carbide nanosheets, graphitic carbon nitride compounds, etc., while the selected heavy two-dimensional materials can be extended to MoO3, Bi2O3, WS2, MoS2, etc. This method can provide a new approach and strategy for the assembly of lightweight and heavy two-dimensional materials and comprehensive protection.

[0053] Another aspect of the present invention provides a protective composite material prepared by the aforementioned method.

[0054] Specifically, the protective schematic diagram of the protective composite material in this invention is as follows: Figure 4 As shown.

[0055] Another aspect of the present invention provides the use of the aforementioned protective composite material in the preparation of nuclear radiation protective equipment.

[0056] This invention utilizes hexagonal boron nitride (h-BN) nanosheets as a two-dimensional lightweight material and tungsten trioxide (WO3) nanosheets as a two-dimensional heavy material. The WO3 nanosheets themselves carry a negative charge, while the surface of the h-BN nanosheets is modified to carry a positive charge, resulting in opposite charges on the surfaces of the two nanosheets. Through the attraction of opposite charges, h-BN and WO3 are successfully assembled, achieving a multi-directional comprehensive protection effect. For nuclear protective clothing applications, the material should be lightweight and flexible, possessing comprehensive protection capabilities against neutrons, X-rays, and gamma rays. X-ray and gamma-ray shielding materials require metal atoms with high atomic numbers (such as iron, lead, and tungsten), while neutron shielding materials commonly use polymers with high hydrogen content (such as polyethylene and polypropylene) and boron-containing compounds (such as B4C). However, due to the significant differences in density and surface properties between heavy metals (compounds) and boron compounds, uniform dispersion during composite processing is difficult, resulting in a low effective protective area and decreased interfacial mechanical properties. To improve shielding effectiveness, the common approach is to increase the content of shielding components, making it difficult to simultaneously achieve lightweighting of key materials in existing nuclear protective suits and comprehensive radiation protection performance. In this invention, through the two-dimensional controllable preparation of tungsten-based and boron-based compound materials and corresponding micro-composite and macro-assembly, the interaction area between the shielding components and radiation can be greatly increased, the interparticle porosity of the shielding material (i.e., protective material) can be significantly reduced, the utilization rate of the shielding material can be improved, and the interfacial forces of heterogeneous materials can be enhanced. This provides an effective method for obtaining lightweight, high-strength composite materials and achieving efficient comprehensive radiation protection capabilities.

[0057] The technical solution of the present invention will be further described in detail below with reference to several preferred embodiments and accompanying drawings. This embodiment is implemented on the premise of the technical solution of the invention, and provides detailed implementation methods and specific operation processes. However, the protection scope of the present invention is not limited to the following embodiments.

[0058] Unless otherwise specified, the experimental materials used in the examples below can be purchased from conventional biochemical reagent companies.

[0059] Example 1

[0060] 100 mg of h-BN was dispersed in 200 ml of ultrapure water, followed by the addition of 1.5 ml of 20% PDDA solution. The mixture was then sonicated at 60 °C for 3 hours to thin the h-BN and modify its surface with a positive charge. Simultaneously, its morphology and thickness were measured using atomic force microscopy (AFM). Figure 1As shown; to synthesize WO3 nanosheets, 100 mg of WO3·H2O powder was dispersed in 200 ml of ultrapure water and sonicated in an ice bath for 4 h. The suspension was then collected by centrifugation at 5000 rpm, and the product was transferred to a vacuum oven and dried at 60 °C for 12 h. It was then transferred to a CVD tube furnace for annealing and held at 350 °C under Ar conditions for 1 h to obtain WO3 nanosheets. The morphology and thickness were then measured using atomic force microscopy (AFM). Figure 2 As shown; next, 50 mg of WO3 nanosheets were dispersed in ultrapure water and mixed with 100 ml of the above h-BN solution for 1 h. The mixture was then collected by centrifugation at 6000 rpm and transferred to a vacuum oven to dry at 60 °C for 12 h. Finally, to ensure stable assembly of the h-BN nanosheets and WO3 nanosheets, the dried product was transferred to a CVD tube furnace for annealing and calcination at 400 °C for 1 h under Ar protection, ultimately yielding a stable two-dimensional assembled material (i.e., a protective composite material). The corresponding XRD phase diagram is shown below. Figure 1 As shown.

[0061] Example 2

[0062] 60 mg of h-BN was dispersed in 200 ml of ultrapure water, followed by the addition of 1.5 ml of 20% PDDA solution. The mixture was then sonicated at 60 °C for 3 h to thin the h-BN and modify its surface with a positive charge. To synthesize WO3 nanosheets, 100 mg of WO3·H2O powder was dispersed in 200 ml of ultrapure water and sonicated in an ice bath for 4 h. The suspension was then collected by centrifugation at 5000 rpm, and the product was transferred to a vacuum oven and dried at 60 °C for 12 h. Finally, it was transferred to a CVD tube furnace for descaling. WO3 nanosheets were obtained by heating at 350℃ and under Ar conditions for 1 hour. Then, 50 mg of WO3 nanosheets were dispersed in ultrapure water and mixed with 100 ml of the above h-BN solution for 1 hour. The mixture was then collected by centrifugation at 6000 rpm and transferred to a vacuum oven to dry at 60℃ for 12 hours. Finally, to ensure the stable assembly of h-BN nanosheets and WO3 nanosheets, the dried product was transferred to a CVD tube furnace for annealing and calcination, and held at 400℃ for 1 hour under Ar protection, finally obtaining a stable two-dimensional assembled material (i.e., a protective composite material).

[0063] Example 3

[0064] 80 mg of h-BN was dispersed in 200 ml of ultrapure water, followed by the addition of 1.5 ml of 20% PDDA solution. The mixture was then sonicated at 60 °C for 3 h to thin the h-BN and modify its surface with a positive charge. To synthesize WO3 nanosheets, 100 mg of WO3·H2O powder was dispersed in 200 ml of ultrapure water and sonicated in an ice bath for 4 h. The suspension was then collected by centrifugation at 5000 rpm, and the product was transferred to a vacuum oven and dried at 60 °C for 12 h. Finally, it was transferred to a CVD tube furnace for descaling. WO3 nanosheets were obtained by heating at 350℃ and under Ar conditions for 1 hour. Then, 50 mg of WO3 nanosheets were dispersed in ultrapure water and mixed with 100 ml of the above h-BN solution for 1 hour. The mixture was then collected by centrifugation at 6000 rpm and transferred to a vacuum oven to dry at 60℃ for 12 hours. Finally, to ensure the stable assembly of h-BN nanosheets and WO3 nanosheets, the dried product was transferred to a CVD tube furnace for annealing and calcination, and held at 400℃ for 1 hour under Ar protection, finally obtaining a stable two-dimensional assembled material (i.e., a protective composite material).

[0065] Example 4

[0066] 120 mg of h-BN was dispersed in 200 ml of ultrapure water, followed by the addition of 1.5 ml of 20% PDDA solution. The mixture was then sonicated at 60 °C for 3 h to thin the h-BN and modify its surface with a positive charge. To synthesize WO3 nanosheets, 100 mg of WO3·H2O powder was dispersed in 200 ml of ultrapure water and sonicated in an ice bath for 4 h. The suspension was then collected by centrifugation at 5000 rpm, and the product was transferred to a vacuum oven and dried at 60 °C for 12 h. Finally, it was transferred to a CVD tube furnace for further processing. Annealing was performed at 350℃ and Ar for 1 hour to obtain WO3 nanosheets. Immediately afterwards, 50 mg of WO3 nanosheets were dispersed in ultrapure water and mixed with 100 ml of the above h-BN solution for 1 hour. The mixture was then collected by centrifugation at 6000 rpm and transferred to a vacuum oven to dry at 60℃ for 12 hours. Finally, to ensure stable assembly of h-BN nanosheets and WO3 nanosheets, the dried product was transferred to a CVD tube furnace for annealing and calcination, and held at 400℃ for 1 hour under Ar protection to obtain a stable two-dimensional assembled material (i.e., a protective composite material).

[0067] Example 5

[0068] 60 mg of graphene oxide was dispersed in 200 ml of ultrapure water, followed by the addition of 1.5 ml of 20% PDDA solution and 15 ml of hydrazine hydrate. The mixture was then stirred at 90 °C for 3 h to obtain positively charged graphene. The solution was then collected by centrifugation at 10,000 rpm and redispersed in ultrapure water. To obtain WO3 nanosheets, 100 mg of WO3·H2O powder was dispersed in 200 ml of ultrapure water and sonicated in an ice bath for 4 h. The suspension was then collected by centrifugation at 5,000 rpm, and the product was transferred to a vacuum oven and dried at 60 °C. After 12 hours, the solution was transferred to a CVD tube furnace for annealing and held at 350°C under Ar conditions for 1 hour to obtain WO3 nanosheets. Immediately afterwards, 50 mg of WO3 nanosheets were dispersed in ultrapure water and mixed with 100 ml of the above h-BN solution for 1 hour. The mixture was then collected by centrifugation at 6000 rpm and transferred to a vacuum oven to dry at 60°C for 12 hours. Finally, to ensure stable assembly of h-BN nanosheets and WO3 nanosheets, the dried product was transferred to a CVD tube furnace for annealing and calcination and held at 400°C for 1 hour under Ar protection to obtain a stable two-dimensional assembled material (i.e., a protective composite material).

[0069] Example 6

[0070] 80 mg of graphene oxide was dispersed in 200 ml of ultrapure water, followed by 1.5 ml of 20% PDDA solution and then 15 ml of hydrazine hydrate. The mixture was stirred at 90 °C for 3 h to obtain positively charged graphene. The solution was then collected by centrifugation at 10,000 rpm and redispersed in ultrapure water. To obtain WO3 nanosheets, 100 mg of WO3·H2O powder was dispersed in 200 ml of ultrapure water and sonicated in an ice bath for 4 h. The suspension was then collected by centrifugation at 5,000 rpm, and the product was transferred to a vacuum oven and dried at 60 °C. After 12 hours, the solution was transferred to a CVD tube furnace for annealing and held at 350°C under Ar conditions for 1 hour to obtain WO3 nanosheets. Immediately afterwards, 50 mg of WO3 nanosheets were dispersed in ultrapure water and mixed with 100 ml of the above h-BN solution for 1 hour. The mixture was then collected by centrifugation at 6000 rpm and transferred to a vacuum oven to dry at 60°C for 12 hours. Finally, to ensure stable assembly of h-BN nanosheets and WO3 nanosheets, the dried product was transferred to a CVD tube furnace for annealing and calcination and held at 400°C for 1 hour under Ar protection to obtain a stable two-dimensional assembled material (i.e., a protective composite material).

[0071] Example 7

[0072] 100 mg of graphene oxide was dispersed in 200 ml of ultrapure water, followed by the addition of 1.5 ml of 20% PDDA solution and 15 ml of hydrazine hydrate. The mixture was then stirred at 90 °C for 3 h to obtain positively charged graphene. The solution was then collected by centrifugation at 10,000 rpm and redispersed in ultrapure water. To obtain WO3 nanosheets, 100 mg of WO3·H2O powder was dispersed in 200 ml of ultrapure water and sonicated in an ice bath for 4 h. The suspension was then collected by centrifugation at 5,000 rpm, and the product was transferred to a vacuum oven and dried at 60 °C. After 12 hours, the solution was transferred to a CVD tube furnace for annealing and held at 350°C under Ar conditions for 1 hour to obtain WO3 nanosheets. Immediately afterwards, 50 mg of WO3 nanosheets were dispersed in ultrapure water and mixed with 100 ml of the above h-BN solution for 1 hour. The mixture was then collected by centrifugation at 6000 rpm and transferred to a vacuum oven to dry at 60°C for 12 hours. Finally, to ensure stable assembly of h-BN nanosheets and WO3 nanosheets, the dried product was transferred to a CVD tube furnace for annealing and calcination and held at 400°C for 1 hour under Ar protection to obtain a stable two-dimensional assembled material (i.e., a protective composite material).

[0073] Example 8

[0074] 120 mg of graphene oxide was dispersed in 200 ml of ultrapure water, followed by the addition of 1.5 ml of 20% PDDA solution and 15 ml of hydrazine hydrate. The mixture was then stirred at 90 °C for 3 h to obtain positively charged graphene. The solution was then collected by centrifugation at 10,000 rpm and redispersed in ultrapure water. To obtain WO3 nanosheets, 100 mg of WO3·H2O powder was dispersed in 200 ml of ultrapure water and sonicated in an ice bath for 4 h. The suspension was then collected by centrifugation at 5,000 rpm, and the product was transferred to a vacuum oven and dried at 60 °C. After 12 hours, the solution was transferred to a CVD tube furnace for annealing and held at 350°C under Ar conditions for 1 hour to obtain WO3 nanosheets. Immediately afterwards, 50 mg of WO3 nanosheets were dispersed in ultrapure water and mixed with 100 ml of the above h-BN solution for 1 hour. The mixture was then collected by centrifugation at 6000 rpm and transferred to a vacuum oven to dry at 60°C for 12 hours. Finally, to ensure stable assembly of h-BN nanosheets and WO3 nanosheets, the dried product was transferred to a CVD tube furnace for annealing and calcination and held at 400°C for 1 hour under Ar protection to obtain a stable two-dimensional assembled material (i.e., a protective composite material).

[0075] Comparative Example 1

[0076] 100 mg of bulk h-BN was dispersed in 200 ml of ultrapure water, followed by the addition of 1.5 ml of 20% PDDA solution. The mixture was then stirred at 60 °C for 3 h to obtain h-BN with a positively charged surface. Next, 100 mg of bulk WO3·H2O powder was dispersed in 200 ml of ultrapure water and stirred for 1 h. The two were then mixed uniformly, and the product was collected by vacuum filtration and dried in a vacuum oven at 60 °C for 12 h. Finally, to ensure stable mixing of h-BN particles and WO3 particles, the dried product was transferred to a CVD tube furnace for annealing and calcination. Under Ar protection, the mixture was held at 400 °C for 1 h to obtain a stable particle mixture (i.e., a protective composite material).

[0077] The protective schematic diagram of the nanoparticles in this comparative example is shown below. Figure 5 As shown.

[0078] Comparative Example 2

[0079] 100 mg of h-BN was weighed and dispersed in 200 ml of ultrapure water, and then sonicated at 60 °C for 3 h to thin the h-BN and obtain h-BN nanosheets. The product was then collected by vacuum filtration and transferred to a vacuum oven to dry at 60 °C for 12 h to finally obtain a stable two-dimensional protective material.

[0080] Comparative Example 3

[0081] 100 mg of WO3·H2O was weighed and dispersed in 200 ml of ultrapure water, and then sonicated at 60 °C for 3 h to thin h-BN to obtain WO3 nanosheets. The product was then collected by vacuum filtration and transferred to a vacuum oven to dry at 60 °C for 12 h to finally obtain a stable two-dimensional protective material.

[0082] In addition, the inventors of this case also conducted experiments with other raw materials, process operations, and process conditions described in this specification, referring to the aforementioned embodiments, and obtained relatively ideal results in all cases.

[0083] It should be understood that the technical solutions of the present invention are not limited to the specific embodiments described above. Any technical modifications made to the technical solutions of the present invention without departing from the spirit and scope of the claims are within the scope of protection of the present invention.

Claims

1. A method for preparing a protective composite material, characterized in that... include: A modified two-dimensional lightweight material is prepared by modifying it with a modifier to at least give the surface of the two-dimensional lightweight material a positive charge; wherein the two-dimensional lightweight material is selected from any one or a combination of two or more of h-BN nanosheets, B4C nanosheets, g-C3N4 nanosheets, B2O3 nanosheets, and graphene oxide nanosheets; and the modifier is selected from polydiallyldimethylammonium chloride and / or polyethyleneimine; Furthermore, the modified two-dimensional lightweight material and the two-dimensional heavy material are self-assembled and then annealed to obtain a protective composite material; wherein the modified two-dimensional lightweight material and the two-dimensional heavy material have opposite charges on their surfaces; the two-dimensional heavy material is selected from any one or a combination of two or more of WO3 nanosheets, MoO3 nanosheets, Bi2O3 nanosheets, WS2 nanosheets, and MoS2 nanosheets.

2. The preparation method according to claim 1, characterized in that: The two-dimensional lightweight material is a two-dimensional lightweight material nanosheet with a thickness of 3~10nm and a size of 1~10μm.

3. The preparation method according to claim 1, characterized in that: The two-dimensional lightweight material is h-BN nanosheets.

4. The preparation method according to claim 2, characterized in that: The two-dimensional lightweight nanosheets were prepared by liquid phase exfoliation. The liquid phase stripping method uses an ultrasonic power of 60-100W and an ultrasonic time of 2-4 hours.

5. The preparation method according to claim 1, characterized in that: The two-dimensional heavy material is a two-dimensional heavy material nanosheet with a thickness of 2~6 nm and a size of 0.1~1 μm.

6. The preparation method according to claim 1, characterized in that: The surface of the two-dimensional heavy material carries a negative charge.

7. The preparation method according to claim 1, characterized in that: The two-dimensional heavy material is WO3 nanosheets.

8. The preparation method according to claim 1, characterized in that: The mass ratio of the modified two-dimensional lightweight material to the two-dimensional heavy material is 3~5:4~6.

9. The preparation method according to claim 1, characterized in that... include: The modified two-dimensional lightweight material and the two-dimensional heavy material were mixed and self-assembled under a stirring rate of 400-800 rpm.

10. The preparation method according to claim 1, characterized in that... include: The self-assembled product was annealed at 300-600°C for 0.5-2 hours in a protective atmosphere. The protective atmosphere is selected from argon; the rate at which the protective atmosphere is introduced is 100~300 sccm.

11. A protective composite material prepared by the method of any one of claims 1-10.

12. Use of the protective composite material of claim 11 in the preparation of nuclear radiation protective equipment.

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