Hydrogen-rich benzoxazine neutron shielding material as well as preparation method and application thereof

Abstract

The invention discloses a hydrogen-rich benzoxazine neutron shielding material as well as a preparation method and application thereof. The hydrogen-rich benzoxazine neutron shielding material is prepared from the following components in percentage by weight: 90-95.5% of hydrogen-rich benzoxazine resin and the balance of functional filler, wherein the functional filler is at least one of compounds containing boron, samarium, europium and gadolinium. The hydrogen-rich benzoxazine resin is used as a polymer matrix, and the compound containing boron, samarium, europium or gadolinium is used as a functional filler to modify the polymer matrix, so that the neutron shielding performance of the composite material is improved.

Description

Technical Field

[0001] The present invention relates to a hydrogen-rich benzoxazine-based neutron shielding material, a preparation method and an application thereof. Background Art

[0002] The operation of nuclear reactors generates a large amount of alpha, beta, gamma rays and neutrons, which not only cause serious damage to equipment and devices, but also pose a serious threat to personal safety. Alpha and beta rays have low energy and weak penetration, making them easy to shield, while neutrons and gamma rays have high energy and strong penetration, and are the focus of the shielding process. Advanced nuclear energy systems require safer, more efficient and miniaturized development. Small modular reactors (SMRs) have the advantages of excellent thermal performance, compact core design, simple facility combination and inherent safety, and are one of the important development directions of various countries. Small modular reactors have limited space and mass, which poses challenges to shielding materials, such as lightweight, high temperature resistance, efficient neutron shielding, and applicability to harsh and complex service environments.

[0003] Benzoxazine materials possess high thermal stability and excellent mechanical properties. Their versatile molecular design capabilities enable the manipulation of their structural properties at the molecular level, resulting in polymer materials that are particularly advantageous for specific applications. Polybenzoxazine resins exhibit low flammability, near-zero shrinkage, high thermal stability, and excellent mechanical properties.

[0004] Ji-Hun Cha et al. at the Korea Advanced Institute of Science and Technology (KAIST) prepared a hydrogen-rich benzoxazine resin as a matrix and doped it with multi-walled carbon nanotubes to create a polymer composite for electromagnetic shielding. However, there are no reports of benzoxazine-based composites being used as neutron shielding materials. There is also a lack of research on functionalizing polybenzoxazine-based materials with neutron-shielding fillers for reactor neutron shielding. Summary of the Invention

[0005] In view of this, the present invention provides a hydrogen-rich benzoxazine-based neutron shielding material, its preparation method and application. A hydrogen-rich benzoxazine resin is used as a polymer matrix and is modified using compounds containing boron (B), samarium (Sm), europium (Eu) or gadolinium (Gd) as functional fillers to enhance the neutron shielding performance of the composite material.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] In a first aspect, the present invention discloses a hydrogen-rich benzoxazine-based neutron shielding material, which is prepared from the following components in percentage by weight:

[0008] Hydrogen-rich benzoxazine resin 90-95.5%,

[0009] Functional filler allowance;

[0010] Wherein, the functional filler is at least one compound containing boron, samarium, europium, and gadolinium.

[0011] As a further solution of the present invention: the hydrogen-rich benzoxazine resin is prepared by emulsion polymerization of a phenol derivative, a diaminoalkane and paraformaldehyde.

[0012] As a further embodiment of the present invention, the preparation method of the hydrogen-rich benzoxazine resin is as follows:

[0013] (1) dissolving a phenol derivative, a diaminoalkane, and paraformaldehyde in an organic solvent at a molar ratio of (2-3):1:(4-6), and stirring the mixture at 55-60° C. for 5-7 hours;

[0014] (2) After the reaction is completed, the product is neutralized with an alkaline solution and the oil phase in the product is separated;

[0015] (3) drying the oil phase by stepwise heating at 60-80° C. for 2-4 hours to obtain a hydrogen-rich benzoxazine resin.

[0016] As a further embodiment of the present invention: the phenol derivative is an alkoxy-substituted phenol.

[0017] As a further embodiment of the present invention, the alkoxy-substituted phenol includes phenols with different oxygen positions and branch lengths, such as at least one of methoxyphenol, ethoxyphenol, propoxyphenol or butoxyphenol, and has the following chemical structure:

[0018]

[0019] Here, R represents an alkyl group of varying carbon chain lengths.

[0020] As a further embodiment of the present invention: the diaminoalkane is 1,2-diaminoethane, 1,4-diaminobutane, 1,6-diaminohexane, 1,8-diaminooctane, 1,11-diaminoundecane or 1,12-diaminododecane.

[0021] As a further solution of the present invention: the functional filler is at least one of tetraboron carbide, boron nitride, samarium trioxide, europium trioxide or gadolinium trioxide.

[0022] In a second aspect, the present invention discloses a method for preparing the above-mentioned hydrogen-rich benzoxazine-based neutron shielding material, comprising the following steps:

[0023] S1. Evenly mix the functional filler and the hydrogen-rich benzoxazine resin according to weight percentage, and inject the mixture into a mold;

[0024] S2. Place the mold at 80-90°C under vacuum to remove air bubbles.

[0025] S3. The mold is then placed at 120-140° C. under vacuum conditions and cured for at least 7 hours to obtain the hydrogen-rich benzoxazine-based neutron shielding material.

[0026] In a third aspect, the present invention discloses the use of the above-mentioned hydrogen-rich benzoxazine-based neutron shielding material as a nuclear reactor polymer shielding material.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] The present invention employs an emulsion polymerization method using phenol, diaminoalkane, and paraformaldehyde as raw materials to prepare a variety of hydrogen-rich benzoxazine resins with excellent mechanical properties and thermal stability. A variety of hydrogen-rich benzoxazine-based composite neutron shielding materials are prepared by modifying the resins using a neutron-shielding phase containing B, Sm, Eu, and Gd as a functional filler. The modified hydrogen-rich benzoxazine resins significantly enhance their neutron-shielding performance, enabling integrated neutron moderation and absorption. This composite shielding material combines excellent mechanical properties, thermal stability, and neutron-shielding performance, and is expected to provide a candidate polymer-based material for reactor shielding.

[0029] Hydrogen, with the highest electron number / mass number, is considered the most effective radiation shielding element. It elastically scatters incident neutrons, effectively moderating them. Elements such as boron, Sm, Eu, and Gd have high thermal neutron absorption cross sections, enabling efficient neutron shielding. Therefore, hydrogen-rich polymers exhibit excellent neutron moderation. Composite shielding materials fabricated from hydrogen-rich polymers doped with functional fillers with high neutron absorption cross sections can achieve integrated fast neutron moderation and absorption, meeting the requirements of reactor neutron protection. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a schematic diagram of the neutron shielding model;

[0031] Figure 2 These are the simulation results of thermal neutron shielding performance of different composite shielding materials. DETAILED DESCRIPTION

[0032] To facilitate understanding of the present invention, the present invention will be described more fully below in conjunction with specific embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to provide a more thorough and comprehensive understanding of the disclosure of the present invention.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0034] Example 1

[0035] (1) 3-Butoxyphenol, 1,12-diaminododecane, and paraformaldehyde were mixed in chloroform at a molar ratio of 2:1:5 (5 mL / g reactant) to obtain a mixture;

[0036] (2) heating the mixture (58°C, water bath) and stirring continuously for 7 h to obtain a reaction product;

[0037] (3) neutralizing the obtained reaction product with 1 mol / L sodium hydroxide aqueous solution and deionized water to adjust to neutrality;

[0038] (4) separating the aqueous phase and the oil phase of the reaction product, and heating the oil phase at 70° C. for 12 h to remove residual water in the oil phase;

[0039] (5) placing the obtained reaction product in a vacuum drying oven and heating it at 90° C. for 4 h under vacuum to remove the residual bubbles in the oil phase to obtain a pretreated hydrogen-rich benzoxazine (HRB) resin;

[0040] (6) 5 wt.% Sm2O3 and 95 wt.% hydrogen-rich benzoxazine resin were uniformly mixed, poured into a polytetrafluoroethylene mold (10 mm × 75 mm) coated with a release agent, and placed in a vacuum drying oven;

[0041] (7) Evacuate the vacuum drying oven, heat it to 120° C., and cure it for 7 h. Then, remove the cured Sm 2 O 3 / hydrogen-rich benzoxazine composite material (5 wt.% Sm 2 O 3 / 95 wt.% HRB) from the mold.

[0042] Example 2

[0043] (1) 3-Methoxyphenol, 1,12-diaminoundecane, and paraformaldehyde were mixed in chloroform at a molar ratio of 2:1:5 (5 mL / g reactant) to obtain a mixture;

[0044] (2) heating the mixture (58°C, water bath) and stirring continuously for 7 h to obtain a reaction product;

[0045] (3) neutralizing the obtained reaction product with 1 mol / L sodium hydroxide aqueous solution and deionized water to adjust to neutrality;

[0046] (4) separating the aqueous phase and the oil phase of the reaction product, and heating the oil phase at 70° C. for 12 h to remove residual water in the oil phase;

[0047] (5) placing the obtained reaction product in a vacuum drying oven and heating it at 90° C. for 4 h under vacuum to remove the remaining bubbles in the oil phase to obtain a pretreated hydrogen-rich benzoxazine resin;

[0048] (6) 5 wt.% B4C and 95 wt.% hydrogen-rich benzoxazine resin were uniformly mixed, poured into a polytetrafluoroethylene mold (10 mm × 75 mm) coated with a release agent, and placed in a vacuum drying oven;

[0049] (7) The vacuum drying oven was heated to 120° C. and cured for 7 h. The cured B4C / hydrogen-rich benzoxazine composite material (5 wt.% B4C / 95 wt.% HRB) was removed from the mold.

[0050] Example 3

[0051] (1) 3-Ethoxyphenol, 1,8-diaminooctane, and paraformaldehyde were mixed in chloroform at a molar ratio of 2:1:5 (5 mL / g reactant) to obtain a mixture;

[0052] (2) heating the mixture (58°C, water bath) and stirring continuously for 7 h to obtain a reaction product;

[0053] (3) neutralizing the obtained reaction product with 1 mol / L sodium hydroxide aqueous solution and deionized water to adjust to neutrality;

[0054] (4) separating the aqueous phase and the oil phase of the reaction product, and heating the oil phase at 70° C. for 12 h to remove residual water in the oil phase;

[0055] (5) placing the obtained reaction product in a vacuum drying oven and heating it at 90° C. for 4 h under vacuum to remove the remaining bubbles in the oil phase to obtain a pretreated hydrogen-rich benzoxazine resin;

[0056] (6) 2.5 wt.% Sm2O3, 2.5 wt.% Gd2O3 and 95 wt.% hydrogen-rich benzoxazine resin were uniformly mixed, poured into a polytetrafluoroethylene mold coated with a release agent, and placed in a vacuum drying oven;

[0057] (7) The vacuum drying oven was heated to 120°C and cured for 7 h, and the cured Sm2O3 / Gd2O3 / hydrogen-rich benzoxazine composite material (2.5 wt.% Sm2O3 / 2.5 wt.% Gd2O3 / 95 wt.% HRB) was taken out from the mold.

[0058] Example 4

[0059] (1) 3-Butoxyphenol, 1,12-diaminododecane, and paraformaldehyde were mixed in chloroform at a molar ratio of 2:1:5 (5 mL / g reactant) to obtain a mixture;

[0060] (2) heating the mixture (58°C, water bath) and stirring continuously for 7 h to obtain a reaction product;

[0061] (3) neutralizing the obtained reaction product with 1 mol / L sodium hydroxide aqueous solution and deionized water to adjust to neutrality;

[0062] (4) separating the aqueous phase and the oil phase of the reaction product, and heating the oil phase at 70° C. for 12 h to remove residual water in the oil phase;

[0063] (5) placing the obtained reaction product in a vacuum drying oven and heating it at 90° C. for 4 h under vacuum to remove the remaining bubbles in the oil phase to obtain a pretreated hydrogen-rich benzoxazine resin;

[0064] (6) 2 wt.% Sm2O3, 2 wt.% Gd2O3, and 1 wt.% B4C were uniformly mixed with 95 wt.% hydrogen-rich benzoxazine resin, poured into a polytetrafluoroethylene mold (10 mm × 75 mm) coated with a release agent, and placed in a vacuum drying oven;

[0065] (7) Evacuate the vacuum drying oven, heat to 120°C, and cure for 7 hours. Remove the cured Sm2O3 / Gd2O3 / B4C / hydrogen-rich benzoxazine composite material (2wt.% Sm2O3 / 2wt.% Gd2O3 / 1wt.% B4C / 95wt.% HRB) from the mold.

[0066] Performance Testing

[0067] Monte Carlo simulation was used to calculate the shielding performance of the composite materials against thermal neutrons. The schematic diagram of the one-dimensional model used in the simulation is shown in the figure below. Figure 1 The fixed neutron source model shown uses an isotropic thermal neutron point source with an average energy of 0.0253 eV. The point source is located 10 cm from the shielding material surface. F5 detectors with a radius of 0.001 cm are placed in front and behind the shielding material to detect the neutron flux before and after passing through the shielding material. The simulation error is controlled to 0.5%. All elements in the shielding material are assumed to be uniformly distributed. The model is located in a vacuum environment, with the surrounding area set as a fully reflecting surface. The Z-axis direction is semi-infinite relative to the XY-axis direction. Incident neutrons are tracked. The neutron flux before passing through the neutron shielding material is represented as I0, and the neutron flux after passing through the shielding material is represented as I. The neutron transmittance ratio I / I0 is used to characterize the shielding capability of the composite shielding material. The calculation formula for I / I0 is as follows:

[0068] I / I0=Ae-∑d (2.2)

[0069] Where A is the accumulation factor, d is the thickness of the shielding material (cm), and Σ is the total macroscopic cross-section of all elements in the composite material (cm). -1 ).

[0070] The simulation results of thermal neutron shielding performance of several composite materials prepared in this study are shown in Figure 2 As can be seen from the figure, the above-mentioned composite materials have excellent shielding effects against thermal neutrons. As the thickness of the shielding layer increases, the shielding performance of the composite materials against thermal neutrons is significantly enhanced. Figure 2 a and Figure 2 In b, the neutron transmittance of 5wt.% Sm2O3 / 95wt.% HRB material and 5wt.% B4C / 95wt.% HRB material decreases rapidly with the increase of material thickness. When the material thickness reaches about 1.5 cm, the transmittance is close to 0. Figure 2 c It can be seen that the neutron transmittance of 2.5wt.% Sm2O3 / 2.5wt.% Gd2O3 / 95wt.% HRB decreases with the increase of material thickness, but the decrease rate is slightly slower than (a) and (b). Figure 2 As shown in Figure d, the neutron transmittance of the 2wt.% Sm2O3 / 2wt.% Gd2O3 / 1wt. B4C / 95wt.% HRB material decreases rapidly with increasing thickness, reaching a similar transmittance at a thickness of approximately 1.0 cm. Regarding shielding material thickness, all materials exhibit the most significant thermal neutron shielding performance in the 0.5–2 cm thickness range.

[0071] Tensile tests were conducted on the composite materials using an Instron 3369 universal testing machine and the standard specimen size specified in GB / T 2567-2021, Test Method for Properties of Cast Resin Bodies. The loading rate was 2 mm / min. Furthermore, a synchronous thermal analyzer (NETZSCH STA 449F3) was used to measure the thermal properties of the materials. The test results are shown in Table 1.

[0072] Table 1 Mechanical and thermal properties of Sm2O3 / hydrogen-rich benzoxazine composites

[0073]

[0074] Although this specification is described according to implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0075] Therefore, the above description is only a preferred embodiment of the present application and is not intended to limit the scope of implementation of the present application; that is, all equivalent modifications made according to the scope of the claims of the present application are within the scope of protection of the claims of the present application.

Claims

1. A hydrogen-rich benzoxazine-based neutron shielding material, characterized in that: It is prepared from the following components in percentage by weight: Hydrogen-rich benzoxazine resin 90-95.5%, Functional filler allowance; Wherein, the functional filler is at least one compound containing boron, samarium, europium, and gadolinium.

2. The hydrogen-rich benzoxazine-based neutron shielding material according to claim 1, characterized in that: The hydrogen-rich benzoxazine resin is prepared by emulsion polymerization of phenol derivatives, diaminoalkane and paraformaldehyde.

3. The hydrogen-rich benzoxazine-based neutron shielding material according to claim 1, characterized in that: The preparation method of the hydrogen-rich benzoxazine resin is as follows: (1) dissolving a phenol derivative, a diaminoalkane, and paraformaldehyde in an organic solvent at a molar ratio of (2-3):1:(4-6), and stirring the mixture at 55-60° C. for 5-7 hours; (2) After the reaction is completed, the product is neutralized with an alkaline solution and the oil phase in the product is separated; (3) drying the oil phase by stepwise heating at 60-80° C. for 2-4 hours to obtain a hydrogen-rich benzoxazine resin.

4. The hydrogen-rich benzoxazine-based neutron shielding material according to claim 2 or 3, characterized in that: The phenol derivative is an alkoxy-substituted phenol.

5. The hydrogen-rich benzoxazine-based neutron shielding material according to claim 4, characterized in that: The alkoxy-substituted phenol is methoxyphenol, ethoxyphenol, propoxyphenol or butoxyphenol.

6. The hydrogen-rich benzoxazine-based neutron shielding material according to claim 2 or 3, characterized in that: The diaminoalkane is 1,2-diaminoethane, 1,4-diaminobutane, 1,6-diaminohexane, 1,8-diaminooctane, 1,11-diaminoundecane or 1,12-diaminododecane.

7. The hydrogen-rich benzoxazine-based neutron shielding material according to claim 1, characterized in that: The functional filler is at least one of tetraboron carbide, boron nitride, samarium trioxide, europium trioxide or gadolinium trioxide.

8. The method for preparing the hydrogen-rich benzoxazine-based neutron shielding material according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1. Evenly mix the functional filler and the hydrogen-rich benzoxazine resin according to weight percentage, and inject the mixture into a mold; S2. Place the mold at 80-90°C under vacuum to remove air bubbles. S3. The mold is then placed at 120-140° C. under vacuum conditions and cured for at least 7 hours to obtain the hydrogen-rich benzoxazine-based neutron shielding material.

9. Use of the hydrogen-rich benzoxazine-based neutron shielding material according to any one of claims 1 to 7 as a nuclear reactor polymer shielding material.

Images