Preparation method of MOF modified foam metal / functional resin composite material for neutron / gamma ray shielding and the material

Abstract

The application provides a preparation method of MOFs modified foam metal / functionally modified resin composite for neutron / gamma ray shielding, and belongs to the technical field of radiation shielding materials; in the application, Gd-MOFs (gadolinium-based organic metal framework) nanosheets with oriented morphology are in-situ grown on the surface of foam metal by a solvothermal method, then BN and WO3 functionalized epoxy resin is vacuum impregnated into the porous structure of the MOFs modified foam metal, and a neutron / gamma ray shielding composite material with a micro-interface mechanical interlocking structure and a macro-interpenetrating phase structure is prepared through step-by-step thermal curing; the preparation method provided in the application is simple, low in cost, can significantly improve the comprehensive performance of mixed radiation field shielding materials, and has important application value in the field of nuclear radiation protection.

Description

Technical Field

[0001] This invention relates to the field of radiation shielding materials technology, and in particular to a method for preparing MOFs-modified foam metal / functionalized resin composite materials for neutron / gamma-ray shielding, as well as the materials themselves. Background Technology

[0002] High-performance radiation shielding materials are crucial for the safe utilization and high-quality development of nuclear energy, serving as an important guarantee for the health of personnel and the normal operation of equipment. Neutrons and gamma rays are two typical targets of external radiation protection in the nuclear field. Due to their different interactions with matter, their radiation shielding mechanisms differ. Neutrons, due to their electrical neutrality, have extremely high penetrating power and require slowing down by light elements in the shielding material before absorption and shielding by elements with large neutron absorption cross-sections. Gamma ray shielding, on the other hand, requires the use of elements with high atomic numbers. Therefore, to achieve neutron / gamma ray mixed radiation field shielding, it is necessary to simultaneously introduce both light and heavy elements into the material.

[0003] Polymer-based composite materials possess advantages such as lightweight and high designability. By introducing different types of radiation-shielding fillers into the polymer matrix, neutron / gamma-ray hybrid radiation field shielding materials can be prepared. To improve the radiation shielding effectiveness of the material, the amount of filler needs to be increased; however, excessive filler content can lead to a significant decrease in the material's mechanical properties. To address this issue, researchers have constructed interpenetrating phase structures by combining polymer-based radiation shielding materials with silanized modified porous framework materials (foam ceramics, foam metals, etc.) to improve the mechanical properties of the composite shielding materials. However, due to the small interaction cross-section between most porous framework materials and radiation, the overall shielding effectiveness of the interpenetrating phase composite materials suffers some loss. Furthermore, silanization, as a general modification method, lacks specificity for controlling the interfacial interactions of heterogeneous materials and optimizing stress transfer, resulting in further room for improvement in the material's mechanical properties. Therefore, in the development of materials for shielding neutron / gamma-ray hybrid radiation fields, how to synergistically enhance the radiation shielding effectiveness and mechanical properties of polymer-based composite materials is a pressing technical challenge in this field. Summary of the Invention

[0004] To address the aforementioned technical challenges, the present invention aims to provide a MOF-modified foam metal / functionalized resin composite material for neutron / gamma-ray shielding and its preparation method. This material is based on the principle of heterogeneous nucleation (without the addition of nucleation-promoting substances). Gd-MOF (gadolinium-based organometallic framework) nanosheets with oriented morphology are grown in situ on a porous foam metal framework using a solvothermal reaction. The MOF-modified foam metal is then composited with BN / WO3 functionalized resin to obtain the neutron / gamma-ray shielding composite material. Simultaneously, through component and structural coupling regulation, the radiation shielding effectiveness and mechanical properties of the composite material are synergistically enhanced. The metal nodes of Gd-MOFs are Gd elements with a very large neutron absorption cross-section, which can significantly improve the radiation shielding effectiveness of the material. The organic nodes of Gd-MOFs have abundant functional groups, which can enhance the chemical interaction between the porous framework and the functionalized resin, thereby improving the mechanical properties of the material. The in-situ grown oriented Gd-MOF nanosheets construct a mechanical interlocking structure between the foam metal and the functionalized resin, further strengthening the mechanical properties of the composite material.

[0005] Specifically, the above-mentioned objective is achieved through the following technical solutions:

[0006] First, this application provides a method for preparing MOFs-modified foam metal / functionalized resin composite materials for neutron / gamma-ray shielding, the specific steps of which are as follows:

[0007] 1) Use hydrochloric acid, deionized water and anhydrous ethanol alternately to ultrasonically clean the foam metal (such as foam nickel, foam copper, foam iron nickel, etc.) to completely remove its surface oxide layer. Then, vacuum dry it at 60-80°C to constant weight, and then place it in the lining of the reaction vessel (preferably a corrosion-resistant polytetrafluoroethylene lining) at a certain angle for later use.

[0008] 2) Gadolinium chloride hexahydrate (GdCl3·6H2O) and 1,2,4,5-benzenetetracarboxylic acid dianhydride (PMDA) were added sequentially to N,N-dimethylformamide (DMF). After magnetic stirring for 10–15 min, the mixed solution (MOF precursor solution) was transferred to a reactor containing foamed metal. The reactor was sealed, and a solvothermal reaction was carried out at 120–150 °C to allow MOFs (metal-organic frameworks) to grow in situ on the surface of the foamed metal. After the reactor cooled to room temperature, the foamed metal was removed, washed with ethanol until no more product was shed, and then vacuum dried at 60–80 °C to constant weight to obtain MOFs-modified foamed metal for later use.

[0009] 3) Mix boron nitride (BN) for neutron shielding, tungsten trioxide (WO3) for gamma-ray shielding, epoxy resin matrix, and epoxy resin curing agent in a mass ratio, and disperse evenly using a planetary stirrer to obtain a precursor solution with neutron / gamma-ray shielding function.

[0010] 4) The MOF-modified foam metal is placed into a mold, and a precursor solution with neutron / gamma-ray shielding function is injected into its pores using a vacuum impregnation process. After curing, the sample is allowed to cool naturally to room temperature and then demolded to obtain the MOF-modified foam metal / functionalized resin composite material for neutron / gamma-ray shielding. The above vacuum impregnation process can reduce the generation of bubbles after resin curing and form an interlocking structure between the resin and the MOFs on the surface of the foam metal.

[0011] The aforementioned “vacuum impregnation process” is a conventional technique in this field, as disclosed in the literature “Wang L, Ma Z, Qiu H, et al. Significantly enhanced electromagnetic interference shielding performances of epoxy nanocomposites with long-range aligned lamellar structures[J].Nano-Micro Letters,2022,14(1):224.”

[0012] Preferably, in step 1) above, the ultrasonic power is 400-500W, the concentration of hydrochloric acid is 0.1-0.5mol / L, and the placement angle (the angle between the foam metal and the inner substrate of the reactor) is in the range of 45°-90°, so that Gd-MOFs nanosheets grow uniformly in situ on the porous metal framework.

[0013] Preferably, in step 2) above, the molar ratio of gadolinium chloride hexahydrate (GdCl3·6H2O), 1,2,4,5-benzenetetracarboxylic acid dianhydride and N,N-dimethylformamide is (4-6):(3-7):100, and the solvothermal reaction time is 2-6 h.

[0014] Preferably, in step 3) above, the planetary stirrer rotates at 3000–5000 rpm, and the mixing time is 30–60 s; the mass ratio of neutron shielding filler boron nitride (BN), gamma-ray shielding filler tungsten trioxide (WO3), epoxy resin matrix, and epoxy resin curing agent is (1–1.2):(9–10.5):(8–9):(2–2.5). Boron nitride is beneficial for improving the neutron shielding performance of the material; tungsten trioxide is beneficial for improving the gamma-ray shielding performance of the material, and this ratio of filler can be better dispersed in the resin.

[0015] Preferably, in step 4) above, the vacuum degree of the vacuum impregnation process is -10 to -30 kPa, and the holding time is 30 to 50 min; this is to protect the morphology of the MOFs during the curing process.

[0016] Preferably, in step 4) above, "curing" refers to a step-by-step curing process, i.e., after pre-curing at room temperature (25°C) and standing for 1–1.5 hours, the material is placed in an oven, heated from room temperature to 30–35°C, held at that temperature for 1–1.5 hours, and then heated to 45–50°C and held for 2 hours, with a heating rate of 3°C / min. This step-by-step curing process prevents the internal stress generated by excessively rapid curing from damaging the MOF nanosheet structure.

[0017] Secondly, this application provides a MOF-modified foam metal / functionalized resin composite material for neutron / gamma ray shielding prepared using the above method.

[0018] Compared with the prior art, the preparation method provided in this application has the following advantages:

[0019] (1) This application uses an in-situ growth method and controls the placement angle parameters to use a foam metal porous framework as a nucleation substrate, so that Gd-MOFs nanosheets modify the porous framework in situ, and the Gd-MOFs nanosheets grow into an oriented morphology, which greatly enhances the interfacial compatibility and thus improves the mechanical properties of the composite material.

[0020] (2) Effectively introducing Gd elements with a large neutron absorption cross section into MOF nanosheets not only improves the mechanical properties of the material, but also enhances the neutron shielding function, thus achieving a synergistic enhancement of the radiation shielding effectiveness and mechanical properties of the composite material.

[0021] (3) The raw materials for preparing composite shielding materials are easy to obtain, the preparation method is simple, the cost is low, and it is suitable for large-scale application. Attached Figure Description

[0022] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used will be briefly described below. Figure 1 A schematic diagram of the preparation route for MOF-modified foam metal / functionalized resin composite materials for neutron / gamma-ray shielding.

[0023] Figure 2 This is a SEM image showing the microstructure of the interface of the composite material obtained in Example 1.

[0024] Figure 3 This is a schematic diagram of the foam metal placement structure in Example 3;

[0025] Among them, 1-MOF precursor liquid, 2-nickel foam, 3-connection point, 4-Teflon liner, 5-angle control rod, and θ is the placement angle.

[0026] Figure 4 The image shows the microstructure of the interface of the composite material prepared in Comparative Example 1 using SEM.

[0027] Figure 5The image shows the microstructure of the interface of the composite material prepared in Comparative Example 2 using SEM.

[0028] Figure 6 The image shows the microstructure of the interface of the composite material prepared in Comparative Example 3 using SEM.

[0029] Figure 7 The image shows the microstructure of the interface of the composite material prepared in Comparative Example 5 using SEM. Detailed Implementation

[0030] Example 1

[0031] In this embodiment, the preparation route of the MOFs-modified foam metal / functionalized resin composite material for neutron / gamma-ray shielding is as follows: Figure 1 As shown, the specific steps are as follows:

[0032] 1) Use 0.3mol / L hydrochloric acid, deionized water and anhydrous ethanol to alternately ultrasonically clean the foam nickel (50mm×50mm×5mm, 20ppi, Shanghai Yinghuixiong Electronic Materials Co., Ltd.) at 400W ultrasonic power to completely remove its surface oxide layer (exhibiting a bright metallic luster). Vacuum dry at 70℃ to constant weight, and then place the foam nickel in the liner of a 300mL reaction vessel at a 90° placement angle (θ) (Shanghai Xiniu Lab Instrument Co., Ltd., liner size 71*138mm, material is polytetrafluoroethylene).

[0033] 2) Gadolinium chloride hexahydrate (GdCl3·6H2O) and 1,2,4,5-benzenetetracarboxylic acid dianhydride (PMDA) were added sequentially to N,N-dimethylformamide (DMF) in a molar ratio of 4:3:100. After magnetic stirring for 10 min, 150 mL of the mixed solution (MOF precursor solution) was transferred to a reactor containing nickel foam. The reactor was sealed and subjected to a solvothermal reaction at 120 °C for 6 h to allow MOFs to grow in situ on the surface of the nickel foam. After the reactor cooled to room temperature, the reacted nickel foam was removed and washed with ethanol until no more product was shed. Then, it was vacuum dried at 70 °C to constant weight to obtain Gd-MOFs modified nickel foam for later use.

[0034] 3) Mix 1g of neutron shielding filler boron nitride (BN), 9g of γ-ray shielding filler tungsten trioxide (WO3), 8g of epoxy resin matrix (E51 grade), and 2g of epoxy resin curing agent (T31 grade). Mix the mixture with a planetary stirrer at 4200rpm for 60s to disperse it evenly and obtain a precursor solution with neutron / γ-ray shielding function.

[0035] 4) The Gd-MOFs-modified nickel foam obtained in step 2) was placed into a mold (50mm×50mm×5mm). A precursor solution with neutron / γ-ray shielding function was injected into its pores using a vacuum impregnation process (held at -30kPa vacuum for 30min) until the Gd-MOFs-modified nickel foam was completely submerged in the precursor. A step-by-step curing procedure was then employed: after pre-curing at room temperature (25℃) for 1 hour, the sample was placed in an oven, heated from room temperature to 30℃ and held for 1 hour, then heated to 45℃ and held for 2 hours, with a heating rate of 3℃ / min. After curing, the sample was allowed to cool naturally to room temperature and demolded to obtain a MOFs-modified foam metal / functionalized resin composite material (50mm×50mm×5mm) for neutron / γ-ray shielding. Its SEM image is shown below. Figure 2 As shown.

[0036] Example 2

[0037] Except for the placement angle of the foam metal in step 1) being 75° and the solvothermal reaction time in step 2) being 2 hours, the other steps and conditions are the same as in Example 1.

[0038] Example 3

[0039] The preparation steps of the MOFs-modified foamed metal / functionalized resin composite material in this embodiment are as follows:

[0040] 1) Use 0.1 mol / L hydrochloric acid, deionized water, and anhydrous ethanol to alternately ultrasonically clean the foamed aluminum (50mm×50mm×5mm, 15ppi) at 450W ultrasonic power, completely removing its surface oxide layer (exhibiting a bright metallic luster). Vacuum dry to constant weight at 70℃, then place it at a 45° angle in the lining of a 300mL reaction vessel. Figure 3 As shown.

[0041] 2) Gadolinium chloride hexahydrate (GdCl3·6H2O) and 1,2,4,5-benzenetetracarboxylic acid dianhydride (PMDA) were added sequentially to N,N-dimethylformamide (DMF) in a molar ratio of 6:7:100. After magnetic stirring for 15 min, 150 mL of the mixed solution (MOF precursor solution) was transferred to a reactor containing aluminum foam. The reactor was sealed and the reaction was carried out at 150 °C for 4 h in a solvothermal manner to allow MOFs to grow in situ on the surface of the aluminum foam. After the reactor cooled to room temperature, the reacted aluminum foam was removed and washed with ethanol until no more products were shed. Then, it was vacuum dried at 80 °C to constant weight to obtain Gd-MOFs modified aluminum foam.

[0042] like Figure 3In the internal structure of the reactor shown, the angle control rod 5 is made of aluminum alloy. Its upper end is connected to the Teflon liner 4 of the reactor via epoxy resin adhesive, and its lower end is connected to the nickel foam 2 via spot welding to form a connection point 3. This controls the placement angle θ formed between the nickel foam 2 and the bottom surface of the Teflon liner 4 of the reactor, and ensures that the foam metal is fully immersed in the MOF precursor solution. In this embodiment, θ = 45°.

[0043] In practice, the placement angle can be adjusted in other ways. As long as the placement angle can be controlled within the range of 45°-90°, the foam metal can grow uniformly.

[0044] 3) The neutron shielding filler boron nitride (BN), the gamma-ray shielding filler tungsten trioxide (WO3), the epoxy resin matrix (E51 grade), and the epoxy resin curing agent (T31 grade) were mixed in the following mass ratios (1.2g, 10.5g, 9g, and 2.5g, respectively). The mixture was stirred using a planetary stirrer at 5000rpm for 30s to ensure uniform dispersion, thus obtaining a precursor solution with neutron / gamma-ray shielding function.

[0045] 4) Place the Gd-MOFs modified aluminum foam into a mold (50mm×50mm×5mm). Use a vacuum impregnation process (holding at -10kPa vacuum for 50min) to pour the precursor solution with neutron / γ-ray shielding function into its pores until the Gd-MOFs modified aluminum foam is submerged in the precursor. Then, use a step-by-step curing procedure: pre-cur at room temperature (25℃) and stand for 1.5h, then place it in an oven, raise the temperature from room temperature to 35℃, hold for 1.5h, raise the temperature to 50℃, and hold for 2h. The heating rate is 3℃ / min. After curing, wait for the sample to cool naturally to room temperature, and then demold to obtain the MOFs modified foam metal / functionalized resin composite material for neutron / γ-ray shielding (50mm×50mm×5mm).

[0046] Example 4

[0047] The preparation steps of the MOFs-modified foamed metal / functionalized resin composite material in this embodiment are as follows:

[0048] 1) Use 0.5mol / L hydrochloric acid, deionized water and anhydrous ethanol to alternately ultrasonically clean the foamed iron-nickel (50mm×50mm×5mm, 25ppi) at 500W ultrasonic power to completely remove its surface oxide layer (exhibiting a bright metallic luster), vacuum dry it at 80°C to constant weight, and then place it in the liner of a 300mL reactor at an 85° angle (same as in Example 1).

[0049] 2) Gadolinium chloride hexahydrate (GdCl3·6H2O) and 1,2,4,5-benzenetetracarboxylic acid dianhydride (PMDA) were added sequentially to N,N-dimethylformamide (DMF) in a molar ratio of 5:5:100. After magnetic stirring for 15 min, 150 mL of the mixed solution was transferred to a reactor containing nickel foam. The reactor was sealed and subjected to a solvothermal reaction at 150 °C for 6 h to allow MOFs to grow in situ on the surface of the nickel foam. After the reactor cooled to room temperature, the reacted nickel foam was removed and washed with ethanol until no more product was shed. Then, it was vacuum dried at 80 °C to constant weight to obtain Gd-MOFs modified nickel foam.

[0050] 3) The neutron shielding filler boron nitride (BN), the gamma-ray shielding filler tungsten trioxide (WO3), the epoxy resin matrix (E51 grade), and the epoxy resin curing agent (T31 grade) were mixed in the following mass ratios (1.1g, 10g, 8g, and 2.5g, respectively). The mixture was stirred with a planetary stirrer at 4500rpm for 45s to ensure uniform dispersion, thus obtaining a precursor solution with neutron / gamma-ray shielding function.

[0051] 4) Place the Gd-MOFs-modified iron-nickel foam into a mold (50mm×50mm×5mm). Using a vacuum impregnation process (holding at -20kPa vacuum for 40min), inject the precursor solution with neutron / γ-ray shielding function into its pores until the Gd-MOFs-modified iron-nickel foam is completely submerged in the precursor. Then, employ a step-by-step curing procedure: pre-cur at room temperature (25℃) for 1.2h, then place in an oven, raise the temperature from room temperature to 35℃, hold for 1.2h, then raise the temperature to 50℃, hold for 2h, with a heating rate of 3℃ / min. After curing, allow the sample to cool naturally to room temperature, then demold to obtain the MOFs-modified foam metal / functionalized resin composite material for neutron / γ-ray shielding (50mm×50mm×5mm).

[0052] Comparative Example 1

[0053] Except for step 4), where the curing process involves holding the product at 50°C for 2 hours, the other steps and conditions are the same as in Example 1.

[0054] Comparative Example 2

[0055] Except for the placement angle of 0° in step 1), the other steps and conditions are the same as in Example 1.

[0056] Comparative Example 3

[0057] Except for the placement angle of 30° in step 1), the other steps and conditions are the same as in Example 1.

[0058] Comparative Example 4

[0059] The functionalized resin composite material prepared in this embodiment does not incorporate a porous metal foam framework. The specific preparation steps are as follows:

[0060] 1) The neutron shielding filler boron nitride (BN), the gamma-ray shielding filler tungsten trioxide (WO3), the epoxy resin matrix (E51 grade), and the epoxy resin curing agent (T31 grade) were mixed in a mass ratio (1g, 9g, 8g, and 2g respectively). The mixture was stirred with a planetary stirrer at a speed of 4500rpm for 60s to disperse it evenly, thus obtaining a precursor solution with neutron / gamma-ray shielding function.

[0061] 2) Pour the precursor solution obtained in 1) into a mold (50mm×50mm×5mm), heat at 50℃ for 2h, and after the sample cools naturally to room temperature, demold to obtain a functionalized resin composite material for neutron / γ-ray shielding (50mm×50mm×5mm).

[0062] Comparative Example 5

[0063] The foamed metal / functionalized resin composite material prepared in this embodiment did not use MOFs to modify the foamed metal. The specific steps are as follows:

[0064] 1) Use 0.3mol / L hydrochloric acid, deionized water and anhydrous ethanol to alternately ultrasonically clean the foam nickel (50mm×50mm×5mm, 20ppi) at 400W ultrasonic power to completely remove its surface oxide layer (exhibiting a bright metallic luster), and vacuum dry it at 70℃ to constant weight for later use.

[0065] 2) Mix 1g of neutron shielding filler boron nitride (BN), 9g of γ-ray shielding filler tungsten trioxide (WO3), 8g of epoxy resin matrix (E51 grade), and 2g of epoxy resin curing agent (T31 grade) (the amounts are 1g, 9g, 8g, and 2g, respectively). Use a planetary stirrer to mix at a speed of 4200rpm to disperse them evenly and obtain a precursor solution with neutron / γ-ray shielding function.

[0066] 3) Place the purified nickel foam obtained in 1) after removing the oxide layer into a mold (50mm×50mm×5mm). Use a vacuum impregnation process (hold at -30kPa vacuum for 30min) to inject the precursor solution with neutron / γ-ray shielding function into its pores until the nickel foam is submerged in the precursor. Then heat at 50℃ for 2h. After the sample cools naturally to room temperature, demold to obtain a neutron / γ-ray shielding foam metal / functionalized resin composite material (50mm×50mm×5mm).

[0067] The radiation shielding performance and mechanical properties of the composite materials prepared in Examples 1-4 and Comparative Examples 1-5 were tested. The thermal neutron shielding performance of the materials was tested using an Am-Be neutron source (moderated) and a He-3 detector, respectively. The gamma-ray shielding performance was tested using a Co-60 source (1.17 MeV, 1.33 MeV), a Cs-137 source (0.662 MeV), and an HPGe detector, respectively. The compressibility was tested according to standard GB / T 5072-2008. The test results are shown in Table 1 below.

[0068] Table 1. Comparison of radiation shielding performance and mechanical properties of the composite materials prepared in the examples and comparative examples.

[0069]

[0070]

[0071] As shown in Table 1, Examples 1, 2, and 3 used different solvothermal reaction times to load Gd-MOF nanosheets of different masses onto porous metal frameworks. It can be seen that with the increase of Gd-MOF nanosheets, both the mechanical properties and thermal neutron shielding performance were significantly improved. Examples 4 and 5 demonstrate that this functionalization method has strong applicability and can grow Gd-MOFs on various metal frameworks.

[0072] Figures 4-7 SEM images of the composite materials prepared in Comparative Examples 1-4 are shown below. It can be seen that the decrease in mechanical properties of Comparative Example 1 compared to Example 1 is due to the excessively rapid resin curing, which damaged the morphology of the Gd-MOF. Figure 4 This disrupted the mechanical interlocking structure. Compared to Example 1, Comparative Examples 2 and 3 exhibited decreased mechanical and shielding properties. This was because the placement angles of Comparative Examples 2 and 3 were too small, resulting in insufficiently uniform in-situ growth of Gd-MOF on nickel foam. Figure 5 , Figure 6 This affects the overall performance of the composite material.

[0073] Compared with Comparative Example 5, Comparative Example 4 shows that interpenetrating phase composite materials have great advantages in mechanical properties, but the shielding performance is reduced because the skeleton occupies a certain volume.

[0074] Compared with Example 1, Comparative Example 5 shows the mechanical interlocking structure formed between Gd-MOF nanosheets and resin. Figure 7 This significantly enhances the mechanical properties, and the introduced Gd element also greatly improves the shielding performance.

Claims

1. A method for preparing MOFs modified foam metal / functionalized resin composite for neutron / gamma ray shielding, characterized by, The specific steps are as follows: 1) After the foamed metal is cleaned and dried, it is placed in a reaction kettle, and the included angle between the foamed metal and the bottom surface of the reaction kettle is 45°-90°, ready for use; 2) After gadolinium chloride hexahydrate, 1,2,4,5-benzene tetracarboxylic dianhydride and N,N-dimethylformamide are uniformly mixed, they are added to the reaction kettle for reaction; after the reaction is completed, the reaction product is dried to constant weight to obtain MOFs modified foamed metal, ready for use; 3) Boron nitride, tungsten trioxide, epoxy resin matrix and epoxy resin curing agent are uniformly mixed to obtain a precursor solution, ready for use; 4) The MOFs modified foamed metal is placed in a mold, the precursor solution is vacuum impregnated, and after the curing is completed, the mold is removed, and the MOFs modified foamed metal / functionalized resin composite material for shielding neutrons / gamma rays is obtained; the curing refers to: pre-curing at room temperature for 1-1.5 h; then heating to 30-35℃ at a rate of 3℃ / min, and keeping the temperature for 1-1.5 h; finally, heating to 45-50℃ at a rate of 3℃ / min, and keeping the temperature for 2 h.

2. The method for preparing a MOFs-modified foamed metal / functionalized resin composite material for neutron / gamma-ray shielding according to claim 1, characterized in that, In step 1), the foamed metal includes at least one of foamed nickel, foamed copper and foamed iron-nickel.

3. The method for preparing a MOFs-modified foamed metal / functionalized resin composite material for neutron / gamma-ray shielding according to claim 1, characterized in that, In step 1), the cleaning refers to alternating ultrasonic cleaning with hydrochloric acid, deionized water and anhydrous ethanol.

4. The method for preparing a MOFs-modified foamed metal / functionalized resin composite material for neutron / gamma-ray shielding according to claim 1, characterized in that, In step 2), the molar ratio of gadolinium chloride hexahydrate, 1,2,4,5-benzene tetracarboxylic dianhydride and N,N-dimethylformamide added is (4-6):(3-7):100, and the reaction time is 2-6 h.

5. The method for preparing a MOFs-modified foamed metal / functionalized resin composite material for neutron / gamma-ray shielding according to claim 1, characterized in that, In step 3), the mass ratio of boron nitride, tungsten trioxide, epoxy resin matrix and epoxy resin curing agent added is (1-1.2):(9-10.5):(8-9):(2-2.5).

6. The method for preparing a MOFs modified foam metal / functionalized resin composite material for neutron / gamma ray shielding according to claim 1, characterized in that, In step 3), the mixing refers to dispersion with a planetary mixer at a speed of 3000-5000 rpm for 30-60 s.

7. The method for preparing a MOFs modified foam metal / functionalized resin composite material for neutron / gamma-ray shielding according to claim 1, characterized in that, In step 4), the vacuum impregnation refers to a vacuum degree of -10 to -30 kPa and an impregnation time of 30-50 min.

8. The MOFs modified foamed metal / functionalized resin composite material for shielding neutrons / gamma rays prepared by any of the methods of claims 1-7.

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