A modified samarium oxide reinforced high-temperature-resistant neutron shielding material and a preparation method thereof

Abstract

The application relates to a modified samarium oxide reinforced high-temperature-resistant neutron shielding material and a preparation method thereof, and belongs to the technical field of neutron shielding materials for nuclear radiation protection. The modified samarium oxide reinforced high-temperature-resistant neutron shielding material is composed of polyamide-imide (PAI) resin and modified samarium oxide (M-Sm2O3); the mass ratio of the PAI resin and the M-Sm2O3 is 9:1 to 7:3; wherein the M-Sm2O3 is samarium oxide (Sm2O3) modified by a silane coupling agent gamma-aminopropyl triethoxysilane (APTES). The M-Sm2O3, which is obtained by modifying the surface of a Sm2O3 neutron absorber by APTES, is introduced into a high-temperature-resistant PAI resin matrix, the interface compatibility of the filler in the matrix is effectively improved, and thus the M-Sm2O3 / PAI composite material which has high-temperature resistance and high-efficiency neutron shielding is prepared.

Description

Technical Field

[0001] This invention belongs to the technical field of neutron shielding materials for nuclear radiation protection, and particularly relates to a modified samarium oxide-reinforced high-temperature neutron shielding material and its preparation method. Background Technology

[0002] Nuclear reactors contain charged particles (such as alpha particles and beta particles) and neutral particles (such as neutrons and photons). Charged particles have weaker penetrating power and are easier to shield, while neutral particles have stronger penetrating power. Therefore, nuclear reactors need to primarily consider radiation safety and shielding issues caused by neutron and photon leakage in order to reduce potential hazards to the surrounding environment and personnel.

[0003] Photons are usually shielded using high-Z elements (such as Pb, Bi, W, etc.), while neutrons have stronger penetrating power and are more harmful than photons at the same dose. Therefore, neutron shielding is the key to radiation protection.

[0004] The unique application environment, miniaturization, and high-temperature operation requirements of small modular reactors (SMRs) place higher demands on the "lightweight and high-temperature resistant" performance of neutron shielding materials. Concrete-based neutron shielding materials experience accelerated internal moisture loss at high temperatures, leading to a decrease in their structural and neutron moderation performance. Stainless steel-based neutron shielding materials possess superior high-temperature mechanical properties as structural materials, while also exhibiting certain neutron shielding performance; however, their large mass per unit volume makes it difficult to meet the lightweight requirements of SMRs.

[0005] Compared to concrete-based and stainless steel-based neutron shielding materials, polymer-based neutron shielding materials offer advantages such as lighter weight per unit volume, higher hydrogen content, and better neutron moderation. Therefore, polymer-based neutron shielding materials are a candidate material for lightweight neutron shielding solutions in SMR (Superconducting Metal-Related Resonance Magnets). However, traditional boron-containing polyethylene neutron shielding materials have a relatively low upper service temperature limit, which cannot meet the requirements of high-temperature service environments in SMR. Therefore, there is an urgent need to develop a high-temperature resistant polymer-based neutron shielding material. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a modified samarium oxide-reinforced high-temperature neutron shielding material that combines high-temperature resistance with efficient neutron shielding.

[0007] A further technical problem to be solved by the present invention is to provide a method for preparing a modified samarium oxide-reinforced high-temperature neutron shielding material.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] A modified samarium oxide-reinforced high-temperature neutron shielding material is prepared by horizontal ball milling and hot pressing, using a high-temperature resistant polyamide-imide resin as the matrix and modified samarium oxide as the neutron absorber. The mass ratio of polyamide-imide resin to modified samarium oxide is 9:1 to 7:3.

[0010] Among them, the modified samarium oxide is samarium oxide modified by the silane coupling agent γ-aminopropyltriethoxysilane.

[0011] The polyamide-imide resin is Torlon 4000. ® Type of resin.

[0012] The preparation method of the above-mentioned modified samarium oxide-enhanced high-temperature neutron shielding material includes the following steps:

[0013] S1: Polyamide-imide resin and modified samarium oxide are ball-milled to obtain a mixture; the mass ratio of polyamide-imide resin to modified samarium oxide is 9:1~7:3;

[0014] S2: The mixture is sieved to obtain mixed powder; specifically, a 12-20 mesh sieve is used to sieve the ball milled material to achieve effective separation of ZrO2 ceramic grinding media and powder raw materials;

[0015] S3: The mixed powder is hot-pressed to obtain a modified samarium oxide-reinforced high-temperature neutron shielding material. Specifically, the mixed powder is uniformly filled into a hollow mold and leveled, then placed in a hot press for hot pressing.

[0016] In step S1, the ball-to-material ratio in the ball milling mixing process is 5:1 to 15:1, and the ball milling speed is 200 to 400 r / min.

[0017] In order to reduce the temperature rise caused by heat accumulation during ball milling, the ball milling mixing process in step S1 adopts an intermittent ball milling mode. The intermittent ball milling mode is a ball milling-cooling method with a single ball milling time of 2~5 min and a cooling time of 5~20 min.

[0018] In the intermittent ball milling mode, the number of ball milling-cooling repetitions is 2 to 50 times.

[0019] Preferably, the ball milling process is carried out in a horizontal ball mill.

[0020] Specifically, the hot pressing process in step S3 includes the following operations:

[0021] First stage: First pre-compression; the temperature of the first pre-compression is 280~330℃, the pressure of the first pre-compression is 2~10 MPa, and the holding time of the first pre-compression is 2~20 min;

[0022] Second stage: First hot pressing; After the first pre-pressing is completed, the first hot pressing stage begins. The temperature of the first hot pressing is 280~330℃, the pressure of the first hot pressing is 2~15 MPa, and the holding time of the first hot pressing is 2~60 min.

[0023] The third stage: secondary pre-compression; after the material obtained from the first hot pressing has cooled, the material is stacked and subjected to secondary pre-compression; the temperature of the secondary pre-compression is 300~380℃, the pressure of the secondary pre-compression is 2~10 MPa, and the holding time of the secondary pre-compression is 2~20min.

[0024] Fourth stage: Secondary hot pressing; After the secondary pre-pressing is completed, the secondary hot pressing stage begins. The temperature of the secondary hot pressing is 300~380℃, the pressure of the secondary hot pressing is 2~15 MPa, and the holding time of the secondary hot pressing is 2~60 min.

[0025] Among them, the polyamide-imide resin in S1 is a polyamide-imide resin that has undergone drying treatment. The drying treatment temperature is 30~80℃ and the time is 6~36 h.

[0026] The modified samarium oxide is prepared through the following steps:

[0027] S11: Mix the γ-aminopropyltriethoxysilane solution with the hydroxylated Sm2O3 solution at a volume ratio of 1:10 to 1:2 to obtain a mixed solution;

[0028] S12: Stir the mixed solution to obtain the reaction product solution. The stirring time is 12-36 h, and the stirring speed is 50-300 r / min.

[0029] S13: Centrifuge the reaction product solution to obtain a solid product; specifically, centrifuge at a speed of 5000~10000 r / min for 1~10 min;

[0030] S14: The solid product is dried and ground to obtain modified samarium oxide powder. The drying temperature is 30~80℃ and the drying time is 6~36 h.

[0031] The preparation process of the γ-aminopropyltriethoxysilane solution is as follows:

[0032] Anhydrous ethanol and deionized water are mixed evenly at a volume ratio of 5:1 to 10:1 to obtain a mixed solvent.

[0033] A mixed solvent and γ-aminopropyltriethoxysilane were mixed in a volume ratio of 10:1 to 50:1 to obtain a mixed solution of γ-aminopropyltriethoxysilane.

[0034] Glacial acetic acid was added dropwise to a mixed solution of γ-aminopropyltriethoxysilane to adjust the pH to 3-6 in order to promote the hydrolysis of APTES, thus obtaining a γ-aminopropyltriethoxysilane solution.

[0035] The preparation process of the hydroxylated Sm₂O₃ solution is as follows: 1–10 g of Sm₂O₃ powder is mixed with 10–50 mL of anhydrous ethanol and sonicated for 10–60 min. In this step, anhydrous ethanol is used as the medium to perform surface hydroxylation treatment on Sm₂O₃, and mechanical stirring promotes the hydrolysis of APTES, allowing its silane groups to form stable chemical bonds with the hydroxyl groups on the Sm₂O₃ surface, thus achieving surface modification. This modification method can improve the interfacial compatibility between Sm₂O₃ and the PAI matrix, which is beneficial for improving the overall performance of the composite material.

[0036] The inventive concept of this invention is as follows:

[0037] This invention, based on the principle of neutron shielding, uses PAI resin with a high hydrogen content as the matrix and stable Sm2O3 as the neutron absorber, and prepares the neutron shielding material through horizontal ball milling and hot pressing. The H element abundant in the PAI molecular chain and the light nuclei such as C, N, and O in the framework can achieve a neutron moderation effect. Furthermore, the Sm element in the composite material can effectively absorb the moderated neutrons, thus contributing to the construction of a "moderation + absorption" neutron shielding structure, thereby giving the composite material good neutron shielding performance. The silanol groups (Si-OH) generated during the hydrolysis of APTES can condense with the hydroxyl groups (Sm-OH) on the surface of Sm2O3 to form stable Si-O-Sm chemical bonds; simultaneously, the amino groups (-NH2) at the molecular chain end can form hydrogen bonds with polar groups such as amide bonds in the polyamide-imide (PAI) matrix. This "bridging" effect constructs the interfacial interaction between the inorganic filler and the organic matrix, thereby improving the interfacial bonding.

[0038] The beneficial effects of this invention are as follows:

[0039] (1) In this invention, Sm2O3 neutron absorber is introduced into a high-temperature resistant PAI resin matrix. The light nuclei in PAI can slow down neutrons, and the Sm element can effectively absorb neutrons, thereby improving the neutron shielding performance of the material. However, in view of the problem of poor interfacial compatibility between Sm2O3 filler and PAI matrix, γ-aminopropyltriethoxysilane (APTES) is used to modify the surface of Sm2O3 to prepare modified samarium oxide (M-Sm2O3), which effectively improves the interfacial compatibility of filler in matrix, thereby preparing M-Sm2O3 / PAI composite material with both high temperature resistance and high neutron shielding.

[0040] (2) The Vicat softening point (VST) of the 10wt% M-Sm2O3 / PAI material of the present invention is approximately 274.4℃, which is about 138.4℃ higher than that of commercial tungsten boron polyethylene material, indicating that it has better temperature resistance. The present invention improves the upper limit of service temperature of neutron shielding materials by using high-temperature resistant PAI resin as the matrix, and finally obtains an advanced composite material that combines lightweight, high temperature resistance and high efficiency neutron shielding performance.

[0041] (3) The 10wt% M-Sm2O3 / PAI material of the present invention still maintains high tensile strength and elongation at break at a high temperature of 170℃, indicating that it has good high-temperature tensile properties, which is conducive to meeting the requirements of high-temperature service environment in SMR.

[0042] (4) When the material thickness is about 2 mm, the neutron shielding efficiency of the 10wt%M-Sm2O3 / PAI and 30wt%M-Sm2O3 / PAI high-temperature neutron shielding materials of the present invention is significantly higher than that of the PAI matrix material, with the neutron shielding efficiency increasing to 51.8% and 85.7% respectively, indicating that the neutron shielding performance of the composite material can be effectively improved by introducing M-Sm2O3.

[0043] (5) This invention uses high-temperature resistant polyamide-imide (PAI) as the matrix resin. Compared with traditional polyethylene materials, PAI has higher temperature resistance and tensile strength. To further improve the neutron shielding performance of the material, M-Sm2O3 was introduced into the PAI matrix through horizontal ball milling and hot pressing. Experimental results show that the neutron shielding performance of the M-Sm2O3 / PAI material is significantly improved compared with the PAI matrix. Attached Figure Description

[0044] Figure 1 X-ray diffraction (XRD) patterns of the PAI matrix prepared in Example 1, M-Sm2O3 prepared in Example 2, 10wt%M-Sm2O3 / PAI, and 30wt%M-Sm2O3 / PAI prepared in Example 3;

[0045] Figure 2The following are the Fourier Transform Infrared (FT-IR) spectra of M-Sm2O3 prepared in Examples 2 and 3;

[0046] Figure 3 The image shown is a scanning electron microscope (SEM) image of M-Sm2O3 prepared in Example 2. Figure 3 Image (a) is a SEM image of Sm2O3. Figure 3 (b) is the SEM image of M-Sm2O3;

[0047] Figure 4 VST test results of the PAI matrix prepared in Example 1 and the 10wt% M-Sm2O3 / PAI prepared in Example 2;

[0048] Figure 5 Thermogravimetric analysis results of PAI matrix prepared in Example 1, 10wt% M-Sm2O3 / PAI prepared in Example 2, and 30wt% M-Sm2O3 / PAI prepared in Example 3 are shown in the figure.

[0049] Figure 6 The room temperature tensile and 170°C high temperature tensile curves of 10wt% M-Sm2O3 / PAI prepared in Example 2;

[0050] Figure 7 The neutron shielding efficiency test results are shown in the figure for the PAI matrix prepared in Example 1, the 10wt% M-Sm2O3 / PAI prepared in Example 2, and the 30wt% M-Sm2O3 / PAI prepared in Example 3. Detailed Implementation

[0051] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0052] The Sm2O3, anhydrous ethanol, γ-aminopropyltriethoxysilane (APTES), and glacial acetic acid used in the embodiments of this invention were all purchased from Maclean's analytical grade reagents. The polyamide-imide (PAI) resin (Torlon 4000) was also used. ® (Type) purchased from SOLVAY.

[0053] The powder raw material mixing equipment used in this invention is a QM-WX4 type horizontal ball mill.

[0054] The hot pressing molding equipment used in this invention is R32022020D. ® Type of hot press.

[0055] The analytical equipment used in this invention is an X'Pert type X-ray diffractometer.

[0056] The infrared spectroscopy equipment used in this invention for analyzing materials is a Spectrum Two Fourier transform infrared analyzer.

[0057] The instrument used in this invention to analyze the microstructure of materials is a SIGMA scanning electron microscope.

[0058] The equipment used in this invention to analyze the Vicat softening point of composite materials is the VTM1200 heat distortion Vicat testing machine.

[0059] The instrument used in this invention to analyze the thermal stability of composite materials is a STA 449 F3 thermogravimetric analyzer.

[0060] The equipment used in this invention to analyze the tensile properties of composite materials is the Instron-3369 electronic universal testing machine.

[0061] This invention employs a self-developed High Intensity DT Neutron Generator (HINEG) combined with the KylinLight neutron radiography system to conduct neutron shielding experiments and analyze the neutron shielding performance of the materials.

[0062] The present invention will be further described in detail below with reference to specific embodiments and comparative examples.

[0063] Example 1:

[0064] Weigh 50 g of PAI resin powder and dry it in a vacuum oven at 80°C for 24 h to remove residual moisture. Evenly fill the dried PAI powder into a hollow mold and smooth it. Then, place it in a hot press for hot pressing. The resulting sample is the PAI matrix, named PAI.

[0065] The process parameters for hot pressing in this embodiment are as follows:

[0066] First stage: Pre-compression; temperature 300℃, pressure 2.5 MPa, holding time 5 min;

[0067] The second stage: hot pressing; after the first pre-pressing, the process moves to the first hot pressing stage, with a temperature of 300℃, a pressure of 7.5 MPa, and a holding time of 20 min, followed by water cooling to room temperature;

[0068] The third stage: secondary pre-compression; after the material obtained from the first hot pressing has cooled, it is stacked and subjected to secondary pre-compression; the temperature of the secondary pre-compression is 330℃, the pressure is 2.5 MPa, and the holding time is 5 min;

[0069] Fourth stage: Secondary hot pressing; The temperature of the secondary hot pressing is 330℃, the pressure is 12.5 MPa, and the holding time is 40 min.

[0070] The phase composition and properties of the PAI matrix material prepared in Example 1 are analyzed below:

[0071] according to Figure 1 The XRD test results of PAI show that when the diffraction angle (2θ) is 10~30°, the defective grains and disordered amorphous regions in the PAI material will significantly broaden the diffraction peaks, indicating that it is mainly a semi-crystalline structure.

[0072] The Vicat softening point of the PAI matrix was tested according to standard GB / T 1633-2025, and the results are shown in the table below. Figure 4 .from Figure 4 It can be seen that the VST of the PAI prepared in Example 1 is approximately 271.9℃, which is about 175℃ higher than that of the polyethylene material, indicating that the PAI matrix has a higher softening temperature. Furthermore, thermal stability analysis of the PAI material was performed, and its thermogravimetric curve is shown below. Figure 5 It can be seen that the temperature point at which its mass loss is 5% (T) 5% The temperature is approximately 484℃.

[0073] Tensile properties of the PAI matrix were tested according to standard GB / T 1040.2-2022. The room temperature and high temperature (170℃) tensile strengths of the PAI matrix were approximately 122 MPa and 52 MPa, respectively, indicating that its tensile strength decreased in high-temperature service environments.

[0074] The neutron shielding performance of the PAI substrate prepared in Example 1 was analyzed using the HINEG neutron source and the KylinLight neutron radiography system. The neutron transmittance is shown in the figure. Figure 7 .from Figure 7 It can be seen that the PAI matrix (M-Sm2O3 content of 0) with thicknesses of approximately 2 mm and 4 mm, respectively, exhibits neutron shielding efficiencies of 8.0% and 29.5%. Since the PAI matrix is ​​mainly composed of light nuclei such as C and H, its shielding mechanism primarily relies on the elastic scattering of neutrons, thereby moderating them. However, the low thermal neutron absorption cross-section of light nuclei results in relatively limited neutron absorption capacity. Given its good high-temperature resistance, high-temperature tensile properties, and neutron moderation performance, this material is suitable as a neutron moderation layer or scattering layer material in high-temperature environments of SMR.

[0075] Example 2:

[0076] Part 1: Preparation of modified samarium oxide (M-Sm2O3).

[0077] Preparation:

[0078] (1) Preparation of Sm2O3 ethanol solution: Take 2.5 g of Sm2O3 powder and place it in a 100 mL beaker, pour in 50 mL of anhydrous ethanol and sonicate for 40 min.

[0079] (2) Preparation of APTES solution: Anhydrous ethanol and deionized water are mixed evenly to obtain a mixed solvent; the mixed solvent is mixed with APTES to obtain a γ-aminopropyltriethoxysilane mixed solution; glacial acetic acid is added dropwise to the γ-aminopropyltriethoxysilane mixed solution to make the pH value 5 to obtain a γ-aminopropyltriethoxysilane solution; wherein the volume ratio of anhydrous ethanol, deionized water and APTES is 9:1:0.25.

[0080] The specific preparation steps for M-Sm2O3 are as follows:

[0081] S11: Slowly add the prepared APTES solution to the Sm2O3 ethanol solution at a volume ratio of 1:5 to obtain a mixed solution;

[0082] S12: The reaction product solution was obtained by mechanically stirring the mixed solution at 200 r / min for 24 h at room temperature;

[0083] S13: Centrifuge the reaction product solution to obtain a solid product; specifically, use a dropper to transfer the reaction product solution into a 7 mL centrifuge tube, place the centrifuge tube containing the solution symmetrically in a centrifuge, and centrifuge at 9000 r / min for 5 min to achieve solid-liquid separation and obtain M-Sm2O3.

[0084] S14: Modified samarium oxide powder is obtained by drying and grinding M-Sm2O3; specifically, the solid product is dried in a vacuum drying oven at 80°C for 24 h, and then ground in an agate mortar to prepare dried M-Sm2O3 powder.

[0085] Part 2: Preparation of modified samarium oxide-reinforced high-temperature neutron shielding material (M-Sm2O3 / PAI).

[0086] PAI resin pretreatment: Weigh 50 g of PAI resin powder and place it in a vacuum oven at 80°C for 24 h to remove residual moisture and obtain dried PAI resin.

[0087] The specific preparation steps for M-Sm2O3 / PAI are as follows:

[0088] S1: Polyamide-imide resin and modified samarium oxide are ball-milled to obtain a mixture; specifically, dried PAI resin and M-Sm2O3 powder are placed in a 500 mL polyurethane ball mill jar at a mass ratio of 9:1, and a certain amount of ZrO2 ceramic balls are added, with a ball-to-material ratio of 11:1, and the ball mill speed is 350 r / min.

[0089] In step S1, to reduce the temperature rise caused by heat accumulation during ball milling, an intermittent ball milling mode is adopted, that is, the ball milling time is 5 minutes per cycle, followed by a 10-minute shutdown for cooling. This "ball milling-cooling" process is repeated 24 times.

[0090] S2: The mixture is sieved to obtain mixed powder; specifically, after the ball milling process is completed, the material is sieved using a 14-mesh sieve to achieve effective separation of the ceramic grinding media and the powder raw material.

[0091] S3: The mixed powder was hot-pressed to obtain a modified samarium oxide-reinforced high-temperature neutron shielding material, named 10wt%M-Sm2O3 / PAI. Specifically, the mixed powder was uniformly filled into a hollow mold and leveled, then placed in a hot press for molding. The hot-pressing process parameters were the same as in Example 1.

[0092] The phase composition and properties of the 10wt% M-Sm2O3 / PAI prepared in Example 2 are analyzed below:

[0093] The XRD results of the 10wt% M-Sm2O3 / PAI prepared in Example 2 are shown in [Figure 2]. Figure 1 It can be seen that the XRD results of the 10wt% M-Sm2O3 / PAI obtained in Example 2 show the characteristic diffraction peaks of M-Sm2O3 (see...). Figure 1 middle (at point number 1), indicating that M-Sm2O3 has been introduced into the composite material, and its crystal structure is relatively stable during ball milling and hot pressing. Figure 1 The XRD results showed that the diffraction peak positions and intensities of the M-Sm2O3 prepared in Example 2 were consistent with those of the PDF card, indicating that it belongs to a body-centered cubic crystal structure.

[0094] The FT-IR results of M-Sm2O3 prepared in Example 2 are shown in Figure 2. Figure 2 . Figure 2 The FT-IR spectra showed that both M-Sm2O3 and the silane coupling agent APTES exhibited characteristic absorption peaks of CH, NH, Si-O, and Si-OC. Compared with Sm2O3, they had the addition of organic functional groups, indicating that APTES had modified the surface of Sm2O3.

[0095] Figure 3The image shown is a scanning electron microscope (SEM) image of M-Sm2O3 prepared in Example 2. Figure 3 Image (a) is a SEM image of Sm2O3. Figure 3 (b) is the SEM image of M-Sm2O3. Figure 3 SEM results showed that the agglomeration degree of Sm2O3 particles was significantly reduced after APTES modification, which is beneficial for its composite with the matrix material.

[0096] The Vicat softening point of the composite material was tested according to standard GB / T 1633-2025. The Vicat softening point test results of 10wt% M-Sm2O3 / PAI material are shown in [reference needed]. Figure 4 .from Figure 4 It can be seen that the VST of 10wt% M-Sm2O3 / PAI is approximately 274.4℃. Furthermore, compared to commercial tungsten boron polyethylene, the VST of 10wt% M-Sm2O3 / PAI is increased by approximately 138.4℃, indicating that it has better temperature resistance.

[0097] In addition, thermal stability analysis was performed on the 10wt% M-Sm2O3 / PAI material of Example 2, and its thermogravimetric curve is shown in [Figure number missing]. Figure 5 It can be seen that its T 5% It is approximately 459℃.

[0098] Tensile properties of the composite material were tested according to standard GB / T 1040.2-2022. The room temperature and 170℃ tensile curves of the 10wt% M-Sm2O3 / PAI material are shown below. Figure 6 It can be seen that the tensile strength and elongation at break of this material at room temperature are 85 MPa and 17%, respectively. When the temperature rises to 170℃, although its tensile strength decreases to 55 MPa, its elongation at break increases to 19%. Compared with the room temperature tensile properties, it exhibits a thermal softening behavior of "reduced strength - increased plasticity".

[0099] The neutron shielding performance of the material was analyzed using the HINEG neutron source and the KylinLight neutron radiography system. The experimental results of neutron shielding for the 10wt% M-Sm2O3 / PAI material are shown in [reference needed]. Figure 7 .from Figure 7It can be seen that when the thickness is approximately 2 mm and 4 mm, the absolute value of its neutron shielding efficiency is increased by approximately 43.8% and 49.7% compared to the PAI matrix material, respectively. This indicates that the 10 wt% M-Sm2O3 / PAI prepared in Example 2, by introducing M-Sm2O3 into the PAI matrix, can significantly improve the neutron absorption effect of the material, thereby improving the neutron shielding performance. Given its good high-temperature resistance, high-temperature tensile properties, and neutron shielding performance, this material is suitable as a neutron shielding layer material in the high-temperature environment of SMR, as well as a nuclear radiation protection material in space nuclear power systems with high requirements for high-temperature mechanical properties and structural stability.

[0100] Example 3:

[0101] In this embodiment, the mass ratio of PAI resin to M-Sm2O3 powder is 7:3, and the rest is the same as in Example 2.

[0102] The process parameters for hot pressing in this embodiment are as follows:

[0103] First stage: Pre-compression; temperature 310℃, pressure 2.5 MPa, holding time 5 min;

[0104] The second stage: hot pressing; after the first pre-pressing, the process proceeds to the first hot pressing, which is carried out at a temperature of 310℃, a pressure of 7.5 MPa, and a holding time of 20 min, followed by water cooling to room temperature;

[0105] The third stage: secondary pre-compression; after the material obtained from the first hot pressing has cooled, it is stacked and subjected to secondary pre-compression. The temperature of the secondary pre-compression is 340℃, the pressure is 2.5 MPa, and the holding time is 5 min.

[0106] Fourth stage: Secondary hot pressing; The temperature of the secondary hot pressing is 340℃, the pressure is 12.5 MPa, and the holding time is 40 min.

[0107] The sample obtained in Example 3 was named 30wt%M-Sm2O3 / PAI.

[0108] The phase composition and properties of the 30wt% M-Sm2O3 / PAI prepared in Example 3 are analyzed below:

[0109] The XRD results of the 30wt% M-Sm2O3 / PAI material are shown in the figure. Figure 1 .from Figure 1 It can be seen that the XRD results of the 30wt% M-Sm2O3 / PAI material show characteristic diffraction peaks of M-Sm2O3 (see...). Figure 1 middle (at point number 1), indicating that M-Sm2O3 has been introduced into the composite material and its crystal structure is relatively stable.

[0110] According to GB / T 1040.2-2022 standard, room temperature tensile tests were conducted on 30wt% M-Sm2O3 / PAI composite materials. The results showed that the tensile strength and elongation at break of the 30wt% M-Sm2O3 / PAI material were 34 MPa and 5%, respectively. Compared with the material with 10wt% M-Sm2O3 addition, the higher M-Sm2O3 addition caused obvious interface defects and stress concentration in the composite material, thereby reducing the tensile properties of the composite material.

[0111] In addition, thermal stability analysis was performed on the 30wt% M-Sm2O3 / PAI material of Example 3, and its thermogravimetric curve is shown in [Figure number missing]. Figure 5 Thermogravimetric analysis results show that the Tg of 30wt% M-Sm2O3 / PAI is... 5% It is approximately 447℃.

[0112] The neutron shielding performance of the material was analyzed using the HINEG neutron source and the KylinLight neutron radiography system. The experimental results of neutron shielding for the 30wt% M-Sm2O3 / PAI material are shown in [reference needed]. Figure 7 It can be seen that when the thickness is approximately 2 mm and 4 mm, the neutron shielding efficiency of 30wt% M-Sm2O3 / PAI reaches 85.7% and 97.8%, respectively, which is about 77.7% and 68.3% higher than the absolute value of the neutron shielding efficiency of PAI matrix material at similar thickness.

[0113] Comparative Example 1:

[0114] Table 1 compares the neutron shielding performance, VST, and room temperature tensile properties of commercial lead-boron polyethylene, tungsten-boron polyethylene (CN110767340B), and the 10wt% M-Sm2O3 / PAI composite material of this invention. The results show that, compared to lead-boron polyethylene and tungsten-boron polyethylene, the material prepared in this invention significantly improves neutron shielding performance while simultaneously increasing its softening temperature and tensile strength, exhibiting better overall performance.

[0115] Comparative Example 2:

[0116] Table 1 compares the thermal stability, room temperature tensile properties, and neutron shielding performance of the carbon nanofiber reinforced samarium-containing epoxy resin (CNFs / Sm2O3 / AFG-90H) prepared by thermosetting method with that of the 10wt% M-Sm2O3 / PAI composite material prepared in this invention. The results show that although the neutron shielding efficiency of 10wt% M-Sm2O3 / PAI is slightly lower than that of the control group, its T0... 5%The temperature was increased by 138°C, while the tensile strength and elongation at break increased by 46 MPa and 16%, respectively. This indicates that the present invention effectively improves the thermal stability and room temperature tensile properties of neutron shielding materials while ensuring good neutron shielding performance.

[0117] Table 1. Performance comparison of M-Sm2O3 / PAI material with other neutron shielding materials

[0118]

[0119] The results above show that the modified samarium oxide-reinforced high-temperature neutron shielding material of the present invention has high-temperature resistance and high-efficiency neutron shielding performance, and is suitable as a neutron shielding material in the high-temperature environment of SMR. The performance comparison results of the material prepared by the present invention with other neutron shielding materials in Table 1 show that: (1) compared with commercial tungsten boron polyethylene material, the softening temperature of the 10wt%M-Sm2O3 / PAI material is increased by 138.4℃, and the room temperature tensile strength is increased by 67 MPa; (2) the material prepared by the present invention has higher tensile strength, softening temperature, and high-efficiency neutron shielding performance. This indicates that the 10wt%M-Sm2O3 / PAI material has great application potential as a novel lightweight, high-temperature neutron shielding material.

[0120] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention. The above embodiments are provided only for the purpose of describing the present invention and are not intended to limit the present invention. Parts not described in detail in this specification are well-known in the art and are not intended to limit the scope of the present invention. The scope of the present invention is defined by the appended claims. All equivalent substitutions and modifications made without departing from the spirit and principle of the present invention should be covered within the scope of the present invention.

Claims

1. A modified samarium oxide-reinforced high-temperature neutron shielding material, characterized in that, The modified samarium oxide-reinforced high-temperature neutron shielding material is prepared by horizontal ball milling and hot pressing molding process using high-temperature resistant polyamide-imide resin as the matrix and modified samarium oxide as the neutron absorber; the mass ratio of polyamide-imide resin to modified samarium oxide is 9:1 to 7:

3. Among them, the modified samarium oxide is samarium oxide modified by the silane coupling agent γ-aminopropyltriethoxysilane.

2. The modified samarium oxide-reinforced high-temperature neutron shielding material according to claim 1, characterized in that, The polyamide-imide resin is Torlon 4000. ® Type of resin.

3. The method for preparing the modified samarium oxide-reinforced high-temperature neutron shielding material according to claim 1 or 2, characterized in that, Includes the following steps: S1: Polyamide-imide resin and modified samarium oxide are ball-milled to obtain a mixture; the mass ratio of polyamide-imide resin to modified samarium oxide is 9:1~7:3; S2: The mixture is sieved to obtain a mixed powder; S3: The mixed powder is hot-pressed to obtain a modified samarium oxide-reinforced high-temperature neutron shielding material.

4. The method for preparing the modified samarium oxide-reinforced high-temperature neutron shielding material according to claim 3, characterized in that, In step S1, the ball-to-material ratio in the ball milling mixing process is 5:1 to 15:1, and the ball milling speed is 200 to 400 r / min.

5. The method for preparing the modified samarium oxide-reinforced high-temperature neutron shielding material according to claim 4, characterized in that, The ball milling mixing process in step S1 adopts an intermittent ball milling mode, which is a ball milling-cooling method with a single ball milling time of 2~5 min and a cooling time of 5~20 min; In the intermittent ball milling mode, the number of ball milling-cooling cycles is 2 to 50.

6. The method for preparing the modified samarium oxide-reinforced high-temperature neutron shielding material according to claim 3, characterized in that, The hot pressing process in step S3 specifically includes the following operations: First stage: First pre-compression; the temperature of the first pre-compression is 280~330℃, the pressure of the first pre-compression is 2~10 MPa, and the holding time of the first pre-compression is 2~20 min; Second stage: First hot pressing; After the first pre-pressing is completed, the first hot pressing stage begins. The temperature of the first hot pressing is 280~330℃, the pressure of the first hot pressing is 2~15 MPa, and the holding time of the first hot pressing is 2~60 min. The third stage: secondary pre-compression; after the material obtained from the first hot pressing has cooled, the material is stacked and subjected to secondary pre-compression; the temperature of the secondary pre-compression is 300~380℃, the pressure of the secondary pre-compression is 2~10 MPa, and the holding time of the secondary pre-compression is 2~20 min. Fourth stage: Secondary hot pressing; After the secondary pre-pressing is completed, the secondary hot pressing stage begins. The temperature of the secondary hot pressing is 300~380℃, the pressure of the secondary hot pressing is 2~15 MPa, and the holding time of the secondary hot pressing is 2~60 min.

7. The method for preparing the modified samarium oxide-reinforced high-temperature neutron shielding material according to claim 3, characterized in that, The polyamide-imide resin in step S1 is a polyamide-imide resin that has undergone drying treatment. The drying treatment temperature is 30~80℃ and the time is 6~36 h.

8. The method for preparing the modified samarium oxide-reinforced high-temperature neutron shielding material according to claim 3, characterized in that, Modified samarium oxide is prepared by the following steps: S11: Mix γ-aminopropyltriethoxysilane solution with hydroxylated Sm2O3 solution at a volume ratio of 1:10 to 1:2 to obtain a mixed solution; S12: Stir the mixed solution to obtain the reaction product solution. The stirring time is 12~36 h. S13: Centrifuge the reaction product solution to obtain a solid product; S14: The solid product is dried and ground to obtain modified samarium oxide powder. The drying temperature is 30~80℃ and the drying time is 6~36 h.

9. The method for preparing the modified samarium oxide-reinforced high-temperature neutron shielding material according to claim 8, characterized in that, The preparation process of γ-aminopropyltriethoxysilane solution is as follows: Anhydrous ethanol and deionized water are mixed evenly at a volume ratio of 5:1 to 10:1 to obtain a mixed solvent. A mixed solvent and γ-aminopropyltriethoxysilane were mixed in a volume ratio of 10:1 to 50:1 to obtain a mixed solution of γ-aminopropyltriethoxysilane. Glacial acetic acid was added dropwise to a mixed solution of γ-aminopropyltriethoxysilane to adjust the pH to 3-6, thus obtaining a γ-aminopropyltriethoxysilane solution.

10. The method for preparing the modified samarium oxide-reinforced high-temperature neutron shielding material according to claim 8, characterized in that, The preparation process of hydroxylated Sm2O3 solution is as follows: 1~10 g of Sm2O3 powder is mixed with 10~50 mL of anhydrous ethanol and sonicated for 10~60 min.

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