Lightweight gamma ray and X ray shielding material and preparation method thereof
By combining Bi2O3@Gd2O3 composite protective particles with polyurethane elastomers, the problem of the difficulty in synergistic effect between Bi2O3 and Gd2O3 in the existing technology has been solved, and a lightweight, broadband, high-efficiency, and mechanically excellent radiation shielding material has been prepared, which is suitable for various protective applications.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-16
- Publication Date
- 2026-03-17
AI Technical Summary
Existing technologies cannot synergistically combine Bi2O3 and Gd2O3, making it difficult to prepare radiation shielding materials that combine lightweight, broadband high-efficiency shielding, and excellent mechanical properties.
By combining Bi2O3@Gd2O3 composite protective particles with polyurethane elastomers and using coupling agent treatment and PMMA segment anchoring technology, stable composite protective particles are formed, thus preparing lightweight gamma-ray and X-ray shielding materials.
It achieves broadband and efficient absorption protection against gamma rays and X-rays, has low material density, excellent mechanical properties, wide applicability, low production cost, and is suitable for large-scale industrial production.
Smart Images
Figure CN121673804A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of radiation protection materials technology. Background Technology
[0002] Gamma rays and X-rays have wide applications in medical diagnosis, tumor treatment, nuclear industry production, and security inspection. However, the ionizing radiation of these rays can cause serious harm to human tissues and the environment, thus requiring shielding materials to effectively block them. Traditional radiation shielding materials primarily use lead as the core protective element. Lead has a high atomic number, high density, and strong absorption capacity for radiation, resulting in excellent shielding performance. However, lead-based shielding materials have a significant drawback: lead's density is 11.34 g / cm³. 3 This results in bulky materials with poor flexibility in use; lead and its compounds are toxic and can easily cause environmental pollution and harm human health during production, use and disposal; in addition, lead-based materials have poor mechanical properties, are prone to deformation and cracking, and affect the stability of protection.
[0003] To address the aforementioned problems of traditional lead-based shielding materials, researchers have focused on developing lead-free, lightweight radiation shielding materials. Bismuth (Bi) and gadolinium (Gd), as high atomic number elements, exhibit excellent absorption properties for gamma rays and X-rays, and their toxicity is far lower than that of lead, making them ideal alternatives to lead. Bi₂O₃ and Gd₂O₃, as common bismuth- and gadolinium-based compounds, possess advantages such as high radiation absorption coefficients and good chemical stability, and have been used to prepare lead-free shielding materials. However, both Bi₂O₃ and Gd₂O₃ are inorganic powders with poor compatibility with organic matrices. Direct addition to the matrix easily leads to agglomeration, resulting in decreased mechanical properties and uneven shielding performance. Furthermore, the shielding effect of Bi₂O₃ or Gd₂O₃ alone is limited for broadband radiation, making it difficult to simultaneously meet the high-efficiency shielding requirements for gamma rays and X-rays.
[0004] Therefore, how to improve the compatibility of Bi2O3 and Gd2O3 with organic matrix through reasonable structural design and prepare radiation shielding materials that are lightweight, have wide-band high-efficiency shielding and excellent mechanical properties has become a research hotspot and key technical challenge in this field. Summary of the Invention
[0005] This invention addresses the limitations of existing technologies in synergistically combining Bi₂O₃ and Gd₂O₃ to improve their compatibility with organic matrices, making it difficult to prepare radiation shielding materials that simultaneously possess lightweight, broadband, high-efficiency shielding, and excellent mechanical properties. Therefore, this invention provides a lightweight gamma-ray and X-ray shielding material and its preparation method.
[0006] A lightweight gamma-ray and X-ray shielding material is composed of a matrix material and a functional filler.
[0007] The matrix material is polyurethane elastomer; the functional filler is Bi2O3@Gd2O3 composite protective particles.
[0008] A method for preparing a lightweight gamma-ray and X-ray shielding material, comprising the following steps:
[0009] I. Preparation of Bi2O3@Gd2O3 composite protective particles:
[0010] ① Add Bi2O3 powder to anhydrous ethanol and disperse it by ultrasonication to obtain Bi2O3 dispersion;
[0011] ② Add the coupling agent to the Bi2O3 dispersion and stir to react. After the reaction, centrifuge, wash and dry to obtain the surface-treated Bi2O3.
[0012] ③ The surface-treated Bi2O3 was added to dichloromethane, then Br initiator was added, and the reaction was carried out under a nitrogen atmosphere. Finally, the mixture was centrifuged, washed and dried to obtain Bi2O3 grafted with Br initiator.
[0013] ④ Mix Bi2O3 and Gd2O3 powders grafted with Br initiator, MMA monomer and initiator, and polymerize them under nitrogen atmosphere. After the reaction, cool, grind and sieve to obtain Bi2O3@Gd2O3 composite protective particles.
[0014] II. Preparation of shielding materials:
[0015] ① The polyurethane elastomer raw materials are heated and stirred to obtain a polyurethane matrix prepolymer;
[0016] ② The Bi2O3@Gd2O3 composite protective particles were added to the polyurethane matrix prepolymer and heated and stirred to disperse them, thus obtaining a mixed slurry;
[0017] ③ Pour the mixed slurry into a mold, heat and vulcanize it, cool it to room temperature and then demold to obtain a lightweight gamma ray and X-ray shielding material.
[0018] The beneficial effects of this invention are:
[0019] 1. This invention uses Bi2O3 and Gd2O3 to synergistically replace traditional Pb. Bi2O3 has excellent absorption effect on medium and high energy gamma rays, while Gd2O3 has strong absorption capacity for low energy X-rays and gamma rays. By utilizing the high atomic number of Bi and the high neutron capture cross-section of Gd, efficient absorption and protection against broadband gamma and X-rays is achieved. Moreover, the toxicity of Bi and Gd is much lower than that of Pb, and there is no risk of secondary pollution.
[0020] 2. By using coupling agent treatment and PMMA segment anchoring technology, Gd2O3 is stably loaded onto the surface of Bi2O3. The resulting composite protective particles have good compatibility with the polyurethane matrix, effectively avoiding the agglomeration of inorganic fillers, resulting in uniform shielding effect and achieving wideband high-efficiency shielding and excellent mechanical properties.
[0021] 3. Using polyurethane elastomer as the matrix and incorporating a lightweight design with composite protective particles, the material density is only 3g / cm³. 3 ~5g / cm 3 It is far lower than that of traditional lead-based materials (11.34 g / cm³). 3 It also has good flexibility and processing performance, and can be made into various forms such as sheets, films, and protective clothing, making it suitable for a wide range of applications.
[0022] 4. The preparation process is simple and controllable, the raw materials are readily available, the production cost is low, it is suitable for large-scale industrial production, and has important practical application value and market prospects. Attached Figure Description
[0023] Figure 1 A cross-sectional SEM image of the Gd2O3@Bi2O3 / TPU shielding material prepared in Example 1;
[0024] Figure 2 The tensile properties of the Gd2O3@Bi2O3 / TPU shielding material prepared in Example 1 are shown. Detailed Implementation
[0025] Specific Implementation Method 1: This implementation method is a lightweight gamma ray and X-ray shielding material, which is composed of a matrix material and a functional filler.
[0026] The matrix material is polyurethane elastomer; the functional filler is Bi2O3@Gd2O3 composite protective particles.
[0027] The beneficial effects of this embodiment are:
[0028] 1. This embodiment uses Bi2O3 and Gd2O3 to synergistically replace traditional Pb. Bi2O3 has excellent absorption effect on medium and high energy gamma rays, while Gd2O3 has strong absorption capacity for low energy X-rays and gamma rays. By utilizing the high atomic number of Bi and the high neutron capture cross-section of Gd, efficient absorption and protection against broadband gamma and X-rays is achieved. Moreover, the toxicity of Bi and Gd is much lower than that of Pb, and there is no risk of secondary pollution.
[0029] 2. By using coupling agent treatment and PMMA segment anchoring technology, Gd2O3 is stably loaded onto the surface of Bi2O3. The resulting composite protective particles have good compatibility with the polyurethane matrix, effectively avoiding the agglomeration of inorganic fillers, resulting in uniform shielding effect and achieving wideband high-efficiency shielding and excellent mechanical properties.
[0030] 3. Using polyurethane elastomer as the matrix and incorporating a lightweight design with composite protective particles, the material density is only 3g / cm³. 3 ~5g / cm 3 It is far lower than that of traditional lead-based materials (11.34 g / cm³). 3 It also has good flexibility and processing performance, and can be made into various forms such as sheets, films, and protective clothing, making it suitable for a wide range of applications.
[0031] 4. The preparation process is simple and controllable, the raw materials are readily available, the production cost is low, it is suitable for large-scale industrial production, and has important practical application value and market prospects.
[0032] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that the mass ratio of Bi2O3 to Gd2O3 in the Bi2O3@Gd2O3 composite protective particles is (1~5):1. Everything else is the same as in Specific Implementation Method One.
[0033] Specific Implementation Method Three: This implementation method differs from Specific Implementation Method One or Two in that the mass fraction of the functional filler in the lightweight gamma-ray and X-ray shielding material is 20%~50%. Everything else is the same as in Specific Implementation Method One or Two.
[0034] Specific Implementation Method Four: This implementation method provides a method for preparing a lightweight gamma-ray and X-ray shielding material, which is carried out according to the following steps:
[0035] I. Preparation of Bi2O3@Gd2O3 composite protective particles:
[0036] ① Add Bi2O3 powder to anhydrous ethanol and disperse it by ultrasonication to obtain Bi2O3 dispersion;
[0037] ② Add the coupling agent to the Bi2O3 dispersion and stir to react. After the reaction, centrifuge, wash and dry to obtain the surface-treated Bi2O3.
[0038] ③ The surface-treated Bi2O3 was added to dichloromethane, then Br initiator was added, and the reaction was carried out under a nitrogen atmosphere. Finally, the mixture was centrifuged, washed and dried to obtain Bi2O3 grafted with Br initiator.
[0039] ④ Mix Bi2O3 and Gd2O3 powders grafted with Br initiator, MMA monomer and initiator, and polymerize them under nitrogen atmosphere. After the reaction, cool, grind and sieve to obtain Bi2O3@Gd2O3 composite protective particles.
[0040] II. Preparation of shielding materials:
[0041] ① The polyurethane elastomer raw materials are heated and stirred to obtain a polyurethane matrix prepolymer;
[0042] ② The Bi2O3@Gd2O3 composite protective particles were added to the polyurethane matrix prepolymer and heated and stirred to disperse them, thus obtaining a mixed slurry;
[0043] ③ Pour the mixed slurry into a mold, heat and vulcanize it, cool it to room temperature and then demold to obtain a lightweight gamma ray and X-ray shielding material.
[0044] In the preparation process of the Bi2O3@Gd2O3 composite protective particles described in this specific embodiment, the selection and dosage of the coupling agent, the grafting amount of the Br initiator, the dosage of the MMA monomer, and the polymerization conditions all affect the dispersion and anchoring effect of the particles. The silane coupling agent can introduce active functional groups on the Bi2O3 surface, providing sites for the grafting of the Br initiator; 2-bromoisobutyryl bromide, as a Br initiator, can efficiently initiate the polymerization of the MMA monomer; by adjusting the dosage of the MMA monomer and the polymerization time, the length of the PMMA chain segments can be controlled, and the entanglement effect of the PMMA chain segments can be used to ensure that Gd2O3 is stably anchored on the Bi2O3 surface, forming structurally stable composite particles.
[0045] The method for preparing the shielding material described in this specific embodiment includes the preparation of Bi2O3@Gd2O3 composite protective particles and their composite molding with polyurethane elastomer. This method is simple, highly controllable, and suitable for industrial production. By optimizing the ratio and amount of the composite protective particles, the shielding performance and mechanical properties of the material can be adjusted according to actual protection requirements.
[0046] Specific Implementation Method Five: This implementation method differs from Specific Implementation Method Four in that: the mass ratio of Bi2O3 powder to anhydrous ethanol in step one ① is 1g:(20~100)mL; the ultrasonic dispersion in step one ① is specifically carried out under a power of 100W~400W for 30min~60min. Everything else is the same as in Specific Implementation Method Four.
[0047] Specific Implementation Method Six: This implementation method differs from Specific Implementation Method Four or Five in that: the coupling agent mentioned in step one (②) is one or a combination of several of KH550, KH560, and KH570; the mass of the coupling agent mentioned in step one (②) is 0.5% to 3% of the mass of Bi2O3 in the Bi2O3 dispersion; the stirring reaction mentioned in step one (②) is specifically carried out at a temperature of 50℃ to 70℃ and a stirring speed of 100 rpm to 300 rpm for 2 to 4 hours. Everything else is the same as in Specific Implementation Method Four or Five.
[0048] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Methods Four to Six in the following ways: the mass ratio of the surface-treated Bi₂O₃ to the volume of dichloromethane in step 1.③ is 1 g:(20~50) mL; the Br initiator in step 1.③ is 2-bromoisobutyryl bromide; the grafting amount of the Br initiator in step 1.③ is 30%~80% of the total molar number of amino, epoxy, and methacryloyloxy functional groups on the surface of the surface-treated Bi₂O₃; the reaction under nitrogen atmosphere in step 1.③ is specifically carried out under nitrogen atmosphere and at a temperature of 30℃~50℃ for 4h~8h. Everything else is the same as in Specific Implementation Methods Four to Six.
[0049] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Methods Four to Seven in the following ways: the initiator mentioned in step one (④) is AIBN; the mass of the initiator mentioned in step one (④) is 0.5% to 2% of the mass of the MMA monomer; the mass of the MMA monomer mentioned in step one (④) is 10% to 30% of the total mass of the Bi2O3 and Gd2O3 powders grafted with Br initiator; the mass ratio of Bi2O3 to Gd2O3 in the Bi2O3@Gd2O3 composite protective particles mentioned in step one (④) is (1 to 5):1; the polymerization reaction in step one (④) under a nitrogen atmosphere is specifically carried out under a nitrogen atmosphere and a temperature of 60℃ to 80℃ for 2 to 6 hours; the sieving in step one (④) is through a 500-1500 mesh sieve. Everything else is the same as in Specific Implementation Methods Four to Seven.
[0050] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Methods Four to Eight in that: the polyurethane elastomer raw material in step two① is isocyanate, polyol, and chain extender; the isocyanate is toluene diisocyanate TDI-100; the polyol is ethylene glycol, propylene glycol, butanediol, or diethylene glycol; the chain extender is 1,4-butanediol; the molar ratio of isocyanate to polyol is (1.05~1.2):1; the mass of the chain extender is 5%~15% of the mass of the polyol; in step two①, the polyurethane elastomer raw material is heated and stirred for 10min~20min at a temperature of 80℃~100℃ and a stirring speed of 100rpm~400rpm. Everything else is the same as in Specific Implementation Methods Four to Eight.
[0051] Specific Implementation Method Ten: This implementation method differs from Specific Implementation Methods Four to Nine in that: the heating, stirring, and dispersing described in step two ② is specifically carried out at a temperature of 60℃~80℃ and a stirring speed of 100r / min~300r / min for 30min~60min; the heating, vulcanizing, and molding described in step two ③ is specifically carried out at a temperature of 100℃~120℃ for 2h~4h. The rest is the same as in Specific Implementation Methods Four to Nine.
[0052] The beneficial effects of the present invention are verified using the following embodiments:
[0053] Example 1:
[0054] A lightweight gamma-ray and X-ray shielding material is composed of a matrix material and a functional filler.
[0055] The matrix material is polyurethane elastomer; the functional filler is Bi2O3@Gd2O3 composite protective particles;
[0056] The mass ratio of Bi2O3 to Gd2O3 in the Bi2O3@Gd2O3 composite protective particles is 3:1; the mass fraction of functional filler in the lightweight gamma ray and X-ray shielding material is 20%.
[0057] The above-mentioned method for preparing a lightweight gamma-ray and X-ray shielding material is carried out according to the following steps:
[0058] I. Preparation of Bi2O3@Gd2O3 composite protective particles:
[0059] ① Add Bi2O3 powder to anhydrous ethanol and ultrasonically disperse for 40 min at a power of 100W to obtain Bi2O3 dispersion.
[0060] The mass ratio of the Bi2O3 powder to the volume ratio of anhydrous ethanol is 1g:50mL.
[0061] ② The coupling agent was added to the Bi2O3 dispersion and stirred for 3 hours at a temperature of 60℃ and a stirring speed of 200 rpm. After the reaction, the mixture was centrifuged, washed and dried to obtain the surface-treated Bi2O3.
[0062] The coupling agent is KH560; the mass of the coupling agent is 2% of the mass of Bi2O3 in the Bi2O3 dispersion.
[0063] ③ Add the surface-treated Bi2O3 to dichloromethane, and then add Br initiator according to the grafting amount of BBr initiator being 50% of the total molar number of amino, epoxy and methacryloyloxy functional groups on the surface of the surface-treated Bi2O3. Under nitrogen atmosphere and temperature of 40℃, react for 6 hours. Finally, centrifuge, wash and dry to obtain Bi2O3 grafted with Br initiator.
[0064] The mass ratio of the surface-treated Bi2O3 to the volume ratio of dichloromethane is 1 g: 30 mL; the Br initiator is 2-bromoisobutyryl bromide;
[0065] ④ Mix Bi2O3 and Gd2O3 powders grafted with Br initiator, MMA monomer and initiator, and polymerize under nitrogen atmosphere and temperature of 70℃ for 4 hours. After reaction, cool, grind and pass through a 1000-mesh sieve to obtain Bi2O3@Gd2O3 composite protective particles.
[0066] The initiator is AIBN; the mass of the initiator is 1% of the mass of the MMA monomer; the mass of the MMA monomer is 20% of the total mass of the Bi2O3 and Gd2O3 powders grafted with Br initiator; the mass ratio of Bi2O3 to Gd2O3 in the Bi2O3@Gd2O3 composite protective particles is 3:1.
[0067] II. Preparation of shielding materials:
[0068] ① Under the conditions of 90℃ and 300rpm, the polyurethane elastomer raw material was heated and stirred for 15min to obtain the polyurethane matrix prepolymer.
[0069] The polyurethane elastomer raw materials are isocyanate, polyol, and chain extender; the isocyanate is toluene diisocyanate TDI-100; the polyol is ethylene glycol; the chain extender is 1,4-butanediol; the molar ratio of isocyanate to polyol is 1.1:1; and the mass of the chain extender is 10% of the mass of the polyol.
[0070] ②The Bi2O3@Gd2O3 composite protective particles were added to the polyurethane matrix prepolymer and heated and stirred for 45 minutes at a temperature of 70℃ and a stirring speed of 200r / min to obtain a mixed slurry.
[0071] ③ Pour the mixed slurry into the mold, vulcanize it at 110℃ for 3 hours, cool it to room temperature and then demold to obtain a lightweight gamma ray and X-ray shielding material, namely Gd2O3@Bi2O3 / TPU shielding material.
[0072] Example 2: This embodiment differs from Example 1 in that the mass fraction of the functional filler in the lightweight gamma-ray and X-ray shielding material is 30%. Everything else is the same as in Example 1.
[0073] Example 3: This embodiment differs from Example 1 in that the mass fraction of the functional filler in the lightweight gamma-ray and X-ray shielding material is 50%. Everything else is the same as in Example 1.
[0074] Table 1
[0075]
[0076] Note: The sample thickness is 1 mm, and the distance from the X-ray exit is 1.5 m.
[0077] Figure 1 The image shows a cross-sectional SEM of the Gd2O3@Bi2O3 / TPU shielding material prepared in Example 1. As can be seen from the image, the formed composite protective particles have good compatibility with the polyurethane matrix, effectively avoiding the agglomeration of inorganic fillers and resulting in a uniform shielding effect.
[0078] Figure 2 The figure shows the tensile properties of the Gd2O3@Bi2O3 / TPU shielding material prepared in Example 1. As shown in the figure, the tensile strength of the Gd2O3@Bi2O3 / TPU shielding material is 5.36 MPa.
[0079] Testing showed that the density of the Gd2O3@Bi2O3 / TPU shielding material prepared in Example 1 was only 3.4 g / cm³. 3 .
Claims
1. A lightweight gamma-ray and X-ray shielding material, characterized in that... It is composed of a matrix material and functional fillers; The matrix material is polyurethane elastomer; the functional filler is Bi2O3@Gd2O3 composite protective particles.
2. The lightweight gamma-ray and X-ray shielding material according to claim 1, characterized in that... The mass ratio of Bi2O3 to Gd2O3 in the Bi2O3@Gd2O3 composite protective particles is (1~5):
1.
3. The lightweight gamma-ray and X-ray shielding material according to claim 1, characterized in that... The mass fraction of functional filler in the lightweight gamma ray and X-ray shielding material is 20% to 50%.
4. The method for preparing a lightweight gamma-ray and X-ray shielding material as described in claim 1, characterized in that... It is done in the following steps: I. Preparation of Bi2O3@Gd2O3 composite protective particles: ① Add Bi2O3 powder to anhydrous ethanol and disperse it by ultrasonication to obtain Bi2O3 dispersion; ② Add the coupling agent to the Bi2O3 dispersion and stir to react. After the reaction, centrifuge, wash and dry to obtain the surface-treated Bi2O3. ③ The surface-treated Bi2O3 was added to dichloromethane, then Br initiator was added, and the reaction was carried out under a nitrogen atmosphere. Finally, the mixture was centrifuged, washed and dried to obtain Bi2O3 grafted with Br initiator. ④ Mix Bi2O3 and Gd2O3 powders grafted with Br initiator, MMA monomer and initiator, and polymerize them under nitrogen atmosphere. After the reaction, cool, grind and sieve to obtain Bi2O3@Gd2O3 composite protective particles. II. Preparation of shielding materials: ① The polyurethane elastomer raw materials are heated and stirred to obtain a polyurethane matrix prepolymer; ② The Bi2O3@Gd2O3 composite protective particles were added to the polyurethane matrix prepolymer and heated and stirred to disperse them, thus obtaining a mixed slurry; ③ Pour the mixed slurry into a mold, heat and vulcanize it, cool it to room temperature and then demold to obtain a lightweight gamma ray and X-ray shielding material.
5. The method for preparing a lightweight gamma-ray and X-ray shielding material according to claim 4, characterized in that... The mass ratio of Bi2O3 powder to anhydrous ethanol in step 1① is 1g:(20~100)mL; the ultrasonic dispersion in step 1① is specifically ultrasonic dispersion for 30min~60min under a power of 100W~400W.
6. The method for preparing a lightweight gamma-ray and X-ray shielding material according to claim 4, characterized in that... The coupling agent mentioned in step 1② is one or a combination of several of KH550, KH560 and KH570; the mass of the coupling agent mentioned in step 1② is 0.5%~3% of the mass of Bi2O3 in the Bi2O3 dispersion; the stirring reaction mentioned in step 1② is specifically carried out at a temperature of 50℃~70℃ and a stirring speed of 100rpm~300rpm for 2h~4h.
7. The method for preparing a lightweight gamma-ray and X-ray shielding material according to claim 4, characterized in that... The mass ratio of the surface-treated Bi2O3 to the volume of dichloromethane in step 1③ is 1 g:(20~50) mL; the Br initiator in step 1③ is 2-bromoisobutyryl bromide; the grafting amount of the Br initiator in step 1③ is 30%~80% of the total molar number of amino, epoxy and methacryloyloxy functional groups on the surface of the surface-treated Bi2O3; the reaction under nitrogen atmosphere in step 1③ is specifically carried out under nitrogen atmosphere and temperature of 30℃~50℃ for 4h~8h.
8. The method for preparing a lightweight gamma-ray and X-ray shielding material according to claim 4, characterized in that... The initiator mentioned in step 1, section 4 is AIBN; the mass of the initiator mentioned in step 1, section 4 is 0.5%~2% of the mass of the MMA monomer; the mass of the MMA monomer mentioned in step 1, section 4 is 10%~30% of the total mass of Bi2O3 and Gd2O3 powders grafted with Br initiator; the mass ratio of Bi2O3 to Gd2O3 in the Bi2O3@Gd2O3 composite protective particles mentioned in step 1, section 4 is (1~5):1; the polymerization reaction mentioned in step 1, section 4 under nitrogen atmosphere is specifically carried out under nitrogen atmosphere and temperature of 60℃~80℃ for 2h~6h; the sieving mentioned in step 1, section 4 is sieving through a 500-1500 mesh sieve.
9. The method for preparing a lightweight gamma-ray and X-ray shielding material according to claim 4, characterized in that... In step 2①, the polyurethane elastomer raw material is isocyanate, polyol, and chain extender; the isocyanate is toluene diisocyanate TDI-100; the polyol is ethylene glycol, propylene glycol, butanediol, or diethylene glycol; the chain extender is 1,4-butanediol; the molar ratio of isocyanate to polyol is (1.05~1.2):1; the mass of the chain extender is 5%~15% of the mass of the polyol; in step 2①, the polyurethane elastomer raw material is heated and stirred for 10min~20min at a temperature of 80℃~100℃ and a stirring speed of 100rpm~400rpm.
10. The method for preparing a lightweight gamma-ray and X-ray shielding material according to claim 4, characterized in that... The heating, stirring and dispersing described in step 2② specifically refers to heating, stirring and dispersing for 30 min to 60 min at a temperature of 60℃ to 80℃ and a stirring speed of 100 r / min to 300 r / min; the heating, vulcanizing and molding described in step 2③ specifically refers to vulcanizing and molding for 2 h to 4 h at a temperature of 100℃ to 120℃.