Boron-samarium-gadolinium co-doped polymer-based neutron shielding material and preparation method thereof

Abstract

The present invention discloses a boron-samarium-gadolinium co-doped polymer-based neutron shielding material, which comprises a polymer material as the matrix and nuclides capable of absorbing neutrons as the doping components. The nuclides are B, Sm, and Gd. In the material, the content of B2O3 is 0.1-3 wt%, the content of Sm2O3 is 0.1-5 wt%, and the content of Gd2O3 is 0.1-5 wt%. The present invention improves the neutron shielding performance of the material by methods such as increasing the content of the neutron shielding phase components and adjusting the ratio. Finally, through experimental optimization, a polymer composite material with high dispersion, neutron shielding ability, mechanical properties, and thermal stability is prepared, providing candidate materials for the polymer-based neutron shielding system of small reactors.

Description

Technical Field

[0001] The present invention relates to the technical field of neutron shielding materials, and in particular to a boron-samarium-gadolinium co-doped polymer-based neutron shielding material and a preparation method thereof. Background Art

[0002] Nuclear safety is the lifeline of nuclear energy development. In traditional reactors, the weight and volume of the shielding layer generally account for more than 20%; while the fourth-generation reactors, especially small reactors, have extremely stringent requirements for radiation safety, and require the shielding layer to be light in weight and small in volume; therefore, efficient radiation shielding is one of the keys to the development of small reactors. Neutrons are uncharged and difficult to interact with other substances, and conventional materials hardly absorb neutrons. Only specific nuclides such as boron, samarium and gadolinium have good neutron absorption functions. However, the mechanical / environmental corrosion properties of the single-substance materials based on these nuclides do not meet the requirements and cannot be used directly. They need to be added to other materials for selection.

[0003] In 2016, Taiyuan University of Technology published "A Nickel-based Boron Carbide Composite Material Doped with Nd:Yttrium, Sm:Gd" (Application No.: 201610764962.3), which is a nickel-based boron carbide composite material prepared with nickel as the matrix, rare earth materials Nd:Yttrium, Sm:Gd as toughening agents, and boron carbide as neutron absorbing materials. A single neutron shielding nuclide faces a complete thermal neutron energy spectrum, and the shielding effect is uneven, making it difficult to meet the demanding service requirements of advanced nuclear energy systems. In addition, neutron shielding materials also have high requirements for mechanical properties and thermal stability, and there is currently no material that can meet these requirements. Summary of the invention

[0004] The main purpose of the present invention is to provide a boron-samarium-gadolinium co-doped polymer-based neutron shielding material having good shielding effect, mechanical properties and thermal stability and a preparation method thereof.

[0005] To achieve the above object, the present invention provides a boron-samarium-gadolinium co-doped polymer-based neutron shielding material, characterized in that it includes a polymer material as a matrix and a nuclide capable of absorbing neutrons as a doping component.

[0006] Furthermore, the nuclides are B, Sm and Gd.

[0007] Furthermore, in the material, B 2 O 3 The content is 0.1~3wt%, Sm 2 O 3 The content is 0.1~5wt%, Gd 2 O 3 The content is 0.1~5wt%.

[0008] Furthermore, the polymer material is trifunctional epoxy resin or polyimide.

[0009] The present invention also provides a method for preparing the boron-samarium-gadolinium co-doped polymer-based neutron shielding material. When the polymer material is a trifunctional epoxy resin, the preparation method comprises the following steps:

[0010] (1) 4,4-diaminodiphenyl sulfone and trifunctional epoxy resin are mixed in a weight ratio of 1:2-3, and stirred in an oil bath at 100-110° C. for 30-60 minutes to prepare a pre-cured resin;

[0011] (2) Vinyltrimethoxysilane was used to treat B 2 O 3 、Sm 2 O 3 , Gd 2 O 3 The nanoparticles are subjected to surface modification to obtain a modified doped mixture;

[0012] (3) adding the modified doped mixture to the pre-cured resin, and continuing to stir for 1 to 2 hours in an oil bath at 100 to 110° C. to obtain a resin mixture;

[0013] (4) pouring the resin mixture into a polytetrafluoroethylene mold coated with a release agent, and placing it in a vacuum drying oven, evacuating the mixture at 100-110° C. to remove bubbles inside the resin mixture, and finally heating the mixture to 150-200° C. to cure for 4-6 hours to obtain the boron-samarium-gadolinium co-doped polymer-based neutron shielding material.

[0014] Furthermore, in step (2), the specific operation mode of surface modification is:

[0015] B 2 O 3 、Sm 2 O 3 , Gd 2 O 3 The nanoparticles are mixed with deionized water, and NaOH is added to adjust the pH value of the solution to 10-11 to obtain an alkaline aqueous solution of the nanoparticles. Vinyltrimethoxysilane is added to the alkaline aqueous solution of the nanoparticles, and the molar ratio of vinyltrimethoxysilane to the nanoparticles is 1-2:1. The temperature is raised to 70-80°C, stirred for 2-3 hours, and then filtered. The filter cake is dried under vacuum conditions at 80-100°C for 24-30 hours to obtain a modified doping mixture.

[0016] The present invention also provides a method for preparing the boron-samarium-gadolinium co-doped polymer-based neutron shielding material. When the polymer material is polyimide, the preparation method comprises the following steps:

[0017] (1) Vinyltrimethoxysilane was used to treat B 2 O 3 、Sm 2 O 3 , Gd 2 O 3 The nanoparticles are subjected to surface modification to obtain a modified doped mixture;

[0018] (2) adding the modified doping mixture into dimethylacetamide to obtain a modified doping mixed solution, wherein the mass of the modified doping mixture accounts for 1 to 10% of the mass of the modified doping mixed solution;

[0019] (3) adding the modified doping mixed solution into liquid polyimide, stirring for 1 to 2 hours in an argon atmosphere at 60° C., to obtain a coating solution;

[0020] (4) coating the coating liquid with a coating device, drying it at high temperature, and then naturally cooling it to room temperature to obtain the boron-samarium-gadolinium co-doped polymer-based neutron shielding material.

[0021] Furthermore, in step (1), the specific operation mode of surface modification is:

[0022] B 2 O 3 、Sm 2 O 3 , Gd 2 O 3 The nanoparticles are mixed with deionized water, and NaOH is added to adjust the pH value of the solution to 10-11 to obtain an alkaline aqueous solution of the nanoparticles. Vinyltrimethoxysilane is added to the alkaline aqueous solution of the nanoparticles, and the molar ratio of vinyltrimethoxysilane to the nanoparticles is 1-2:1. The temperature is raised to 70-80°C, stirred for 2-3 hours, and then filtered. The filter cake is dried under vacuum conditions at 80-100°C for 24-30 hours to obtain a modified doping mixture.

[0023] Furthermore, in step (4), the high temperature drying process is: heating at 80-120°C for 2-3h, heating at 130-170°C for 3-5h, and heating at 330-370°C for 2-3h.

[0024] The beneficial effects of the present invention are embodied in:

[0025] The present invention uses polyimide (PI) with good thermal stability and trifunctional epoxy resin (AFG-90H) as matrix materials, adopts oxides such as B, Sm and Gd as main additives (neutron shielding phase), designs the amount of each additive without affecting the dispersibility, and realizes the maximization of the neutron shielding absorption function of the material. Under the premise of ensuring thermal stability, the present invention improves the neutron shielding performance of the material by increasing the neutron shielding phase component, adjusting the ratio and the like, and finally prepares a polymer composite material with dispersion, neutron shielding ability, mechanical properties and high thermal stability through experimental optimization, providing a candidate material for a polymer-based neutron shielding system of a small reactor.

[0026] In different energy ranges, the thermal neutron absorption cross sections of B, Sm, and Gd will show a "complementary" phenomenon, that is, in some energy ranges, the thermal neutron absorption cross section of Gd is greater than B / Sm, while in other energy ranges, the opposite phenomenon will occur. The present invention is the first to design a polymer-based shielding material containing different shielding nuclides, and a multi-component (B, Sm and Gd-based compound) co-doped high-efficiency composite neutron shielding material, which improves the comprehensive performance of the material from multiple angles such as increasing the total effective neutron absorption cross section and expanding the neutron absorption spectrum peak, and increases the amount of neutron shielding phase incorporated as much as possible under the premise that the function meets the requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a photo of the material prepared in Example 1 of the present invention;

[0028] Figure 2 This is a photo of the material obtained in Example 4 of the present invention. DETAILED DESCRIPTION

[0029] The present invention is further described in detail below in conjunction with specific embodiments. Those of ordinary skill in the art will be able to implement the present invention based on these descriptions. In addition, the embodiments of the present invention involved in the following description are generally only embodiments of a part of the present invention, rather than all embodiments. Therefore, based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work should fall within the scope of protection of the present invention.

[0030] Unless otherwise specified, the raw materials used in the examples of the present invention are all commercially available or available to those skilled in the art; unless otherwise specified, the methods used in the examples of the present invention are all methods known to those skilled in the art.

[0031] Example 1

[0032] Preparation and performance testing of boron-samarium-gadolinium co-doped polymer-based neutron shielding materials

[0033] In this embodiment, trifunctional epoxy resin AFG-90H is used as the matrix. 2 O 3 The content is 1wt%, Sm 2 O 3 The content is 1wt%, Gd 2 O 3 The content is 3wt%, and the preparation method comprises the following steps:

[0034] (1) 30 g of 4,4-diaminodiphenyl sulfone and 60 g of AFG-90H were mixed and stirred in an oil bath at 105° C. for 30 min to prepare a pre-cured resin;

[0035] (2) 1g B 2 O 3 , 1g Sm 2 O 3 , 3g Gd 2 O 3 The nanoparticles were mixed with 100 g of deionized water, and NaOH was added to adjust the pH to 10 to obtain an alkaline aqueous solution of the nanoparticles. 4.8 g of vinyltrimethoxysilane was added to the alkaline aqueous solution of the nanoparticles, and the temperature was raised to 75° C. and stirred for 2 h. The solution was then filtered and the filter cake was dried under vacuum at 90° C. for 24 h to obtain a modified doping mixture.

[0036] (3) adding the modified doped mixture to the pre-cured resin and continuing to stir for 1 h in an oil bath at 105° C. to obtain a resin mixture;

[0037] (4) pouring the resin mixture into a polytetrafluoroethylene mold coated with a release agent, and placing it in a vacuum drying oven, evacuating at 100° C. to remove bubbles inside the resin mixture, and finally heating to 180° C. to cure for 5 hours to obtain the boron-samarium-gadolinium co-doped polymer-based neutron shielding material.

[0038] The actual photos of the materials prepared in this embodiment are as follows Figure 1 The thermodynamic properties are shown in Table 1.

[0039] Example 2

[0040] Preparation and performance testing of boron-samarium-gadolinium co-doped polymer-based neutron shielding materials

[0041] In this embodiment, trifunctional epoxy resin AFG-90H is used as the matrix. 2 O 3 The content is 3wt%, Sm 2 O 3 The content is 5wt%, Gd 2 O 3 The content is 1wt%, and the preparation method comprises the following steps:

[0042] (1) 28 g of 4,4-diaminodiphenyl sulfone and 58 g of AFG-90H were mixed and stirred in an oil bath at 100° C. for 60 min to prepare a pre-cured resin;

[0043] (2) 3g B 2 O 3 、5g Sm 2 O 3 , 1g Gd 2 O 3 The nanoparticles were mixed with 100 g of deionized water, and NaOH was added to adjust the pH to 11 to obtain an alkaline aqueous solution of the nanoparticles. 5 g of vinyltrimethoxysilane was added to the alkaline aqueous solution of the nanoparticles, and the temperature was raised to 70° C. and stirred for 3 h. The mixture was then filtered and the filter cake was dried under vacuum at 100° C. for 26 h to obtain a modified doping mixture.

[0044] (3) adding the modified doped mixture to the pre-cured resin, and continuing to stir for 2 h in an oil bath at 100° C. to obtain a resin mixture;

[0045] (4) pouring the resin mixture into a polytetrafluoroethylene mold coated with a release agent, and placing it in a vacuum drying oven, evacuating at 105° C. to remove bubbles inside the resin mixture, and finally heating to 150° C. to cure for 6 hours to obtain the boron-samarium-gadolinium co-doped polymer-based neutron shielding material.

[0046] The thermodynamic properties of the material prepared in this example are shown in Table 1.

[0047] Example 3

[0048] Preparation and performance testing of boron-samarium-gadolinium co-doped polymer-based neutron shielding materials

[0049] In this embodiment, trifunctional epoxy resin AFG-90H is used as the matrix. 2 O 3 The content is 2wt%, Sm 2 O 3 The content is 3wt%, Gd 2 O 3 The content is 5wt%, and the preparation method comprises the following steps:

[0050] (1) 28 g of 4,4-diaminodiphenyl sulfone and 56 g of AFG-90H were mixed and stirred in an oil bath at 110° C. for 45 min to prepare a pre-cured resin;

[0051] (2) 2g B 2 O 3 、3g Sm 2 O 3 , 5g Gd2 O 3 The nanoparticles were mixed with 100 g of deionized water, and NaOH was added to adjust the pH to 11 to obtain an alkaline aqueous solution of the nanoparticles. 6.2 g of vinyltrimethoxysilane was added to the alkaline aqueous solution of the nanoparticles, and the temperature was raised to 80° C. and stirred for 2 h. The mixture was then filtered and the filter cake was dried under vacuum at 80° C. for 30 h to obtain a modified doped mixture.

[0052] (3) adding the modified doped mixture to the pre-cured resin, and continuing to stir for 1.5 h in an oil bath at 110° C. to obtain a resin mixture;

[0053] (4) pouring the resin mixture into a polytetrafluoroethylene mold coated with a release agent, and placing it in a vacuum drying oven, evacuating the mixture at 110° C. to remove bubbles inside the resin mixture, and finally heating the mixture to 200° C. to cure for 4 hours to obtain the boron-samarium-gadolinium co-doped polymer-based neutron shielding material.

[0054] The thermodynamic properties of the material prepared in this example are shown in Table 1.

[0055] Table 1 Thermodynamic properties of boron-samarium-gadolinium co-doped polymer-based neutron shielding materials

[0056] Material AFG-90H(blank) Example 1 Example 2 Example 3 Tensile strength(MPa) 42 51 48 40 <![CDATA[T 5％ Thermal decomposition temperature (℃)]]> 352 359 350 342 <![CDATA[T 10％ Thermal decomposition temperature (℃)]]> 381 394 376 364

[0057] Example 4

[0058] Preparation and performance testing of boron-samarium-gadolinium co-doped polymer-based neutron shielding materials

[0059] In this embodiment, polyimide PI is used as the matrix. 2 O 3 The content is 1wt%, Sm 2 O 3 The content is 1wt%, Gd 2 O 3 The content is 2wt%, and the preparation method comprises the following steps:

[0060] (1) 1g B 2 O 3 , 1g Sm 2 O 3 , 2g Gd 2 O 3 The nanoparticles were mixed with 100 g of deionized water, and a NaOH solution was added to adjust the pH to 10 to obtain an alkaline aqueous solution of the nanoparticles. 4 g of vinyltrimethoxysilane was added to the alkaline aqueous solution of the nanoparticles, and the temperature was raised to 75° C. and stirred for 2 h. The solution was then filtered and the filter cake was dried under vacuum at 90° C. for 24 h to obtain a modified doping mixture.

[0061] (2) adding the modified doped mixture into 100 g of dimethylacetamide to obtain a modified doped mixed solution;

[0062] (3) adding the modified doped mixed solution to 92 g of liquid polyimide, stirring for 1.5 h in an argon atmosphere at 60° C. to obtain a coating solution;

[0063] (4) coating the coating liquid with a coating device, and then drying it at high temperature. The high temperature drying process is: heating at 100° C. for 3 h, heating at 150° C. for 4 h, and heating at 350° C. for 2 h, and then naturally cooling to room temperature to obtain the boron-samarium-gadolinium co-doped polymer-based neutron shielding material.

[0064] The actual photos of the materials prepared in this embodiment are as follows Figure 2 The thermodynamic properties are shown in Table 2.

[0065] Example 5

[0066] Preparation and performance testing of boron-samarium-gadolinium co-doped polymer-based neutron shielding materials

[0067] In this embodiment, polyimide PI is used as the matrix. 2 O 3 The content is 2wt%, Sm 2 O 3 The content is 3wt%, Gd 2 O 3 The content is 3wt%, and the preparation method comprises the following steps:

[0068] (1) 2g B 2 O 3 、3g Sm 2 O 3 , 3g Gd 2 O 3 The nanoparticles were mixed with 100 g of deionized water, and a NaOH solution was added to adjust the pH to 11 to obtain an alkaline aqueous solution of the nanoparticles. 5 g of vinyltrimethoxysilane was added to the alkaline aqueous solution of the nanoparticles, and the temperature was raised to 70° C. and stirred for 3 h. The solution was then filtered and the filter cake was dried under vacuum at 95° C. for 26 h to obtain a modified doped mixture.

[0069] (2) adding the modified doped mixture into 100 g of dimethylacetamide to obtain a modified doped mixed solution;

[0070] (3) adding the modified doped mixed solution to 87 g of liquid polyimide, stirring for 1 h in an argon atmosphere at 60° C. to obtain a coating solution;

[0071] (4) coating the coating liquid with a coating device, and then drying it at high temperature. The high temperature drying process is: heating at 80° C. for 2.5 h, heating at 170° C. for 3 h, and heating at 330° C. for 3 h, and then naturally cooling to room temperature to obtain the boron-samarium-gadolinium co-doped polymer-based neutron shielding material.

[0072] The thermodynamic properties of the material prepared in this example are shown in Table 2.

[0073] Example 6

[0074] Preparation and performance testing of boron-samarium-gadolinium co-doped polymer-based neutron shielding materials

[0075] In this embodiment, polyimide PI is used as the matrix. 2 O 3 The content is 1.5wt%, Sm 2 O 3 The content is 2wt%, Gd 2 O 3 The content is 4wt%, and the preparation method comprises the following steps:

[0076] (1) 1.5 g B 2 O 3 , 2g Sm 2 O 3 4g Gd 2 O 3 The nanoparticles were mixed with 100 g of deionized water, and a NaOH solution was added to adjust the pH to 10 to obtain an alkaline aqueous solution of the nanoparticles. 4.5 g of vinyltrimethoxysilane was added to the alkaline aqueous solution of the nanoparticles, and the temperature was raised to 75° C. and stirred for 3 h. The solution was then filtered and the filter cake was dried under vacuum at 100° C. for 24 h to obtain a modified doping mixture.

[0077] (2) adding the modified doped mixture into 100 g of dimethylacetamide to obtain a modified doped mixed solution;

[0078] (3) adding the modified doped mixed solution to 88 g of liquid polyimide, stirring for 2 h in an argon atmosphere at 60° C. to obtain a coating solution;

[0079] (4) coating the coating liquid with a coating device, and then drying it at high temperature. The high temperature drying process is: heating at 120° C. for 2 h, heating at 130° C. for 5 h, and heating at 370° C. for 2 h, and then naturally cooling to room temperature to obtain the boron-samarium-gadolinium co-doped polymer-based neutron shielding material.

[0080] The thermodynamic properties of the material prepared in this example are shown in Table 2.

[0081] Table 2 Thermodynamic properties of boron-samarium-gadolinium co-doped polymer-based neutron shielding material I

[0082] Material PI(blank) Example 4 Example 5 Example 6 Tensile strength(MPa) 66.8 82.5 70.5 66.3 <![CDATA[T 5％ Thermal decomposition temperature (℃)]]> 653.8 632.6 614.2 600.5 <![CDATA[T 10％ Thermal decomposition temperature (℃)]]> 592.5 568.0 531.4 521.8

[0083] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a boron-samarium-gadolinium co-doped polymer-based neutron shielding material, It is characterized in that The boron-samarium-gadolinium co-doped polymer-based neutron shielding material comprises a polymer material as a matrix and a nuclide capable of absorbing neutrons as a doping component, wherein the nuclide is B, Sm and Gd. 2 O 3 The content is 0.1~3wt%, Sm 2 O 3 Content is 0.1~5wt%, Gd 2 O 3 The content is 0.1-5wt%, the polymer material is polyimide, and the preparation method comprises the following steps: (1) Vinyltrimethoxysilane was used to treat B 2 O 3 、Sm 2 O 3 , Gd 2 O 3 The nanoparticles are subjected to surface modification to obtain a modified doped mixture; The specific operation mode of surface modification is: B 2 O 3 、Sm 2 O 3 , Gd 2 O 3 The nanoparticles are mixed with deionized water, and NaOH is added to adjust the pH of the solution to 10-11 to obtain an alkaline aqueous solution of the nanoparticles, vinyltrimethoxysilane is added to the alkaline aqueous solution of the nanoparticles, and the molar ratio of vinyltrimethoxysilane to the nanoparticles is 1-2:1, the temperature is raised to 70-80° C., and stirred for 2-3 hours, and then filtered, and the filter cake is dried under vacuum conditions at 80-100° C. for 24-30 hours to obtain a modified doping mixture; (2) adding the modified doping mixture into dimethylacetamide to obtain a modified doping mixed solution, wherein the mass of the modified doping mixture accounts for 1 to 10% of the mass of the modified doping mixed solution; (3) adding the modified doping mixed solution into liquid polyimide, stirring for 1 to 2 hours in an argon atmosphere at 60° C. to obtain a coating solution; (4) The coating liquid is coated with a coating device, and then dried at high temperature, and then naturally cooled to room temperature to obtain the boron-samarium-gadolinium co-doped polymer-based neutron shielding material.

2. The method for preparing the boron-samarium-gadolinium co-doped polymer-based neutron shielding material according to claim 1, It is characterized in that In step (4), the high temperature drying process is: heating at 80-120°C for 2-3h, heating at 130-170°C for 3-5h, and heating at 330-370°C for 2-3h.

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