Neutron and gamma composite shielding material based on solvent-free tungsten-based fluid as well as preparation method and application of neutron and gamma composite shielding material

Abstract

The invention discloses a neutron and gamma composite shielding material based on solvent-free tungsten-based fluid as well as a preparation method and application of the neutron and gamma composite shielding material, and belongs to the technical field of radiation protection. According to the composite shielding material disclosed by the invention, a solvent-free tungsten-based fluid is prepared by grafting a silane coupling agent-polyether amine organic molecular long chain on the surface of the nano WO3 powder, so that the surface energy of the nano WO3 is reduced, and the interfacial compatibility between the nano WO3 powder as a filler and a thermoplastic polyurethane matrix is improved; the dispersity of the nano WO3 powder in a matrix is increased, the agglomeration phenomenon of nano particles is reduced, and the shielding performance of the composite shielding material is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of radiation protection, and in particular relates to a neutron and gamma composite shielding material based on a solvent-free tungsten-based fluid, and a preparation method and application thereof. Background Art

[0002] In recent years, with the continuous expansion of nuclear power plants, the acceleration of human space exploration, the popularization of clinical radiological diagnosis and treatment technology, and the continued existence of realistic factors such as the threat of nuclear weapons terrorism, humans are facing an increasing risk of exposure to ionizing radiation and nuclear radiation. Radiation is mainly divided into two categories: nuclear radiation and non-ionizing radiation. Nuclear radiation is the most harmful to humans. Nuclear radiation refers to particles or electromagnetic radiation released from the nucleus, including alpha particles, beta particles, gamma rays and neutrons. Nuclear energy is widely used, but it is also accompanied by a demand for radiation shielding materials. In the nuclear energy industry, medical imaging equipment and other radiation applications, effective neutron and gamma ray shielding materials are needed to protect personnel and equipment from the hazards of radiation. Traditional shielding materials usually have some limitations, such as heavy weight, high cost, and limited shielding effect.

[0003] Neutrons are neutral particles that cannot be shielded by electric charge. Neutron shielding usually requires the use of the nuclear reaction properties of materials, which mainly rely on the following physical processes: (1) Scattering: Neutrons scatter with atomic nuclei in the material, changing the direction of the neutrons and weakening their energy. (2) Absorption: Neutrons are absorbed by atomic nuclei in the material, resulting in excitation or fission of the nuclei, thereby reducing the number of neutrons. (3) Deceleration: Neutrons collide with atomic nuclei in the material, gradually lose energy, and eventually decelerate to the thermal neutron state. In order to effectively shield neutrons, materials rich in light elements (such as hydrogen and boron) are usually required because these elements have high scattering and absorption cross-sections for neutrons. For example, materials such as hydrides, boron hydrides, water, and polymers all have good neutron shielding properties. Gamma rays are high-energy electromagnetic radiation, and their shielding mainly relies on the following processes: (1) Photoelectric effect: Gamma rays interact with atoms in matter, transferring energy to electrons in atoms, causing them to be released. (2) Compton scattering: Gamma rays scatter with electrons in matter, changing the direction and energy of gamma rays. (3) Electron pair effect: High-energy gamma rays interact with atomic nuclei in materials to produce positive and negative electron pairs, thereby weakening the energy of the rays. In order to effectively shield gamma rays, high-density materials such as lead, tungsten, and uranium are usually required, as these materials have a high absorption capacity for gamma rays.

[0004] The application of nuclear radiation shielding materials has a long history. Traditionally, metal elements such as lead, iron, tungsten, cadmium, and materials such as concrete, polyethylene, paraffin, and water have played a key role in protecting against a single type of radiation (such as gamma rays or neutrons). However, with the increasing complexity of modern radiation protection scenarios and the harshness of the physical environment, the demand for radiation shielding materials has also significantly upgraded. They not only need to exhibit excellent thermodynamic properties, but must also effectively resist the challenges of mixed radiation fields of neutrons and gamma rays. Existing organic composite shielding materials for neutrons and gamma rays usually have good flexibility and processability, but their shielding performance is far inferior to that of inorganic materials: lead, concrete, etc. Therefore, how to improve the shielding effect of organic composite materials against neutrons and gamma rays while maintaining good mechanical properties and chemical stability is a key challenge. Summary of the invention

[0005] The purpose of the present invention is to provide a neutron and gamma composite shielding material based on a solvent-free tungsten-based fluid and a preparation method and application thereof, so as to solve the problem of poor shielding performance of organic composite shielding materials.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions: The present invention discloses a neutron and gamma composite shielding material based on a solvent-free tungsten-based fluid. The neutron and gamma composite shielding material based on a solvent-free tungsten-based fluid uses nano WO3 powder as a neutron and gamma ray absorber and thermoplastic polyurethane as a matrix material. The WO3 powder is added to the matrix material in the form of a solvent-free tungsten-based fluid. Measured by mass percentage, the components of the neutron and gamma composite shielding material based on solvent-free tungsten-based fluid are: 9.91-50% of nano WO3 powder and 50-90.09% of thermoplastic polyurethane.

[0007] The present invention also discloses a method for preparing the above-mentioned neutron and gamma composite shielding material based on solvent-free tungsten-based fluid, comprising the following steps: The organic silane-polyetheramine solution and the nano-WO3 powder are mixed and reacted to obtain a reaction solution; The reaction solution is dialyzed and rotary evaporated in sequence to obtain a solvent-free tungsten-based fluid; The tetrahydrofuran solution of the solvent-free tungsten-based fluid and the tetrahydrofuran solution of the thermoplastic polyurethane are mixed, and then magnetic stirring and ultrasonic treatment are performed in sequence to obtain a casting solution; The casting liquid is dropped onto a polytetrafluoroethylene film for film-forming treatment to obtain a neutron and gamma composite shielding material based on a solvent-free tungsten-based fluid.

[0008] Furthermore, the preparation method of the organosilane-polyetheramine solution is: The polyetheramine organic polymer is dispersed in methanol, magnetically stirred, and then γ-glycidyloxypropyltrimethoxysilane is added, followed by condensation and reflux to obtain an organic silane-polyetheramine solution; The mass ratio of the polyetheramine organic polymer to methanol is 1:(7-10); The γ-glycidyloxypropyltrimethoxysilane and the polyetheramine organic high molecular polymer are in equimolar amounts; The condensation reflux is carried out in an oil bath, and the temperature of the oil bath is 45-60°C.

[0009] Furthermore, the mass ratio of the nano WO3 powder to the organosilane-polyetheramine solution is 1:(4-10); The dialysis conditions are as follows: the dialysis time is 24 to 60 hours, and the water is changed every 4 to 6 hours during the dialysis process.

[0010] Furthermore, the tetrahydrofuran solution of thermoplastic polyurethane is prepared by mixing thermoplastic polyurethane particles and tetrahydrofuran solution; the mass percentage of thermoplastic polyurethane in the tetrahydrofuran solution of thermoplastic polyurethane is 15% to 30%; The tetrahydrofuran solution of the solvent-free tungsten-based fluid is prepared by mixing the solvent-free tungsten-based fluid and the tetrahydrofuran solution; the mass percentage of the solvent-free tungsten-based fluid in the tetrahydrofuran solution of the solvent-free tungsten-based fluid is 15% to 30%.

[0011] Furthermore, the mass ratio of the solvent-free tungsten-based fluid to the thermoplastic polyurethane in the casting solution is (1:9) to (1:1).

[0012] Furthermore, the magnetic stirring time is 2 to 6 hours; the ultrasonic treatment time is 2 to 6 hours.

[0013] Furthermore, the specific steps of the film forming process are: The polytetrafluoroethylene film is spread flat on the surface of the casting machine, vacuum is drawn, the speed of the casting machine and the film thickness are adjusted, the casting liquid is dropped on the polytetrafluoroethylene film, and the scraper is used to scrape the casting liquid at a uniform speed, and then a neutron and gamma composite shielding material based on a solvent-free tungsten-based fluid is obtained after drying.

[0014] Furthermore, the drying temperature is 40-60°C.

[0015] Furthermore, the speed of the tape casting machine is 10-20 mm / s; and the film thickness is 0.02-0.15 mm.

[0016] Compared with the prior art, the present invention has the following beneficial effects: The invention discloses a neutron and gamma composite shielding material based on a solvent-free tungsten-based fluid. The solvent-free tungsten-based fluid is prepared by grafting a silane coupling agent-polyetheramine organic molecule long chain on the surface of a nano WO3 powder, thereby reducing the surface energy of the nano WO3, improving the interface compatibility between the nano WO3 powder and a thermoplastic polyurethane matrix when the nano WO3 powder is used as a filler, increasing the dispersion of the nano WO3 powder in the matrix, reducing the agglomeration of nano particles, improving the shielding performance of the composite shielding material, and solving the problem of poor shielding performance of traditional organic composite shielding materials.

[0017] Furthermore, in the neutron and gamma composite shielding materials based on solvent-free tungsten-based fluids, nano-WO3 powder is doped. Since WO3 is a hard inorganic material with excellent properties of high hardness and high strength, it is added to the TPU (thermoplastic polyurethane) matrix as a reinforcing agent. There is a certain degree of physical or chemical interaction in the interface area formed between WO3 and TPU. This interface interaction can enhance the bonding force and interface adhesion of the composite material, thereby improving the strength of the material and improving the thermal stability and mechanical properties of the composite material to a certain extent. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a physical picture of the neutron and gamma composite shielding material based on solvent-free tungsten-based fluid prepared by the present invention; Figure 2 This is a SEM image of the neutron and gamma composite shielding material based on solvent-free tungsten-based fluid prepared by the present invention; Where: a-surface; b-section; Figure 3 This is a performance image of the neutron and gamma composite shielding material based on solvent-free tungsten-based fluid prepared by the present invention; Wherein: a-tensile properties; b-elongation at break. DETAILED DESCRIPTION

[0019] In order to enable those skilled in the art to understand the characteristics and effects of the present invention, the following is a general description and definition of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used in the text are the common meanings understood by those skilled in the art for the present invention. In the event of a conflict, the definition in this specification shall prevail.

[0020] The theories or mechanisms described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, that is, the present invention can be implemented without being limited by any specific theory or mechanism.

[0021] In this article, all features such as values, quantities, contents and concentrations defined in the form of numerical ranges or percentage ranges are for simplicity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be considered to have included and specifically disclosed all possible secondary ranges and individual values ​​within the range (including integers and fractions).

[0022] In this document, unless otherwise specified, “includes,” “including,” “contains,” “has,” or similar terms cover the meanings of “consisting of” and “mainly consisting of,” for example, “A includes a” covers the meanings of “A includes a and other” and “A only includes a.”

[0023] In this document, in order to make the description concise, not all possible combinations of various technical features in various embodiments or examples are described. Therefore, as long as there is no contradiction in the combination of these technical features, the various technical features in various embodiments or examples can be combined arbitrarily, and all possible combinations should be considered to be within the scope of this specification.

[0024] The present invention provides a method for preparing a neutron and gamma composite shielding material based on a solvent-free tungsten-based fluid, comprising the following steps: Step 1: Weigh the polyetheramine organic polymer (M2070), disperse it in methanol, stir it magnetically at room temperature to mix it evenly, add an equal molar amount of γ-glycidyloxypropyltrimethoxysilane (KH560), transfer it to a round-bottom flask, place it in an oil bath at 45-60°C for condensation and reflux, and obtain an organic silane-polyetheramine solution (methanol solution of KH560-M2070); Step 2: The methanol solution of KH560-M2070 obtained above was transferred to a stoppered conical flask, and then nano-WO3 powder was added, and magnetic stirring was performed at room temperature to allow the mixture to react fully to obtain a reaction solution; Step 3: The reaction solution obtained above is dialyzed with a dialysis bag for 24 to 60 hours, and the water is changed every 4 to 6 hours to remove the ungrafted organic polymer long chains. After the dialysis is completed, the residual solvent (deionized water, methanol) is evaporated under reduced pressure using a rotary condenser to obtain a solvent-free tungsten-based fluid (WO3@KH560-M2070); Step 4: Prepare a tetrahydrofuran solution of thermoplastic polyurethane (TPU) with a mass percentage of 15% by weight: weigh TPU particles and dissolve them in the tetrahydrofuran solution, add a magnetic stirrer to mix them evenly; Step 5: Prepare a tetrahydrofuran solution of WO3@KH560-M2070 with a mass percentage of 15% by weight: weigh WO3@KH560-M2070 and dissolve it in the tetrahydrofuran solution, add a magnetic stirrer to mix it evenly; Step 6: Prepare the casting solution: mix the prepared 15% WO3@KH560-M2070 tetrahydrofuran solution and 15% TPU tetrahydrofuran solution, add a magnetic bar, stir at room temperature for 2-6 hours, and ultrasonicate for 2-6 hours to prepare the required casting solution; Step 7: Turn on the casting machine for heating, spread the polytetrafluoroethylene film on the surface of the casting machine, evacuate, adjust the casting machine speed and film thickness, drop the casting liquid on the polytetrafluoroethylene film, and make the scraper scrape the casting liquid at a uniform speed to form a TPU modified film with uniform thickness, and then dry it in an oven at 40~60℃ to obtain a neutron and gamma composite shielding material based on solvent-free tungsten-based fluid (solvent-free tungsten-based fluid / TPU composite material).

[0025] Preferably, in step 1, the mass ratio of the polyetheramine organic polymer to methanol is 1:(7-10).

[0026] Preferably, in step 6, the mass ratio of WO3@KH560-M2070 to TPU in the casting solution is 1:9 to 1:1.

[0027] The thermoplastic polyurethane (TPU) used in the present invention is a thermoplastic elastomer, which is prepared by the reaction of polyether or polyester polyols with diisocyanate compounds. It has good mechanical properties, outstanding chemical stability, excellent plasticity and good radiation protection properties. It is used as a matrix and modified with surface-modified functional nanoparticles to improve the dispersion of nanofillers in the matrix, improve the interface compatibility between the filler and the matrix material, and enhance the mechanical properties and radiation shielding properties of the composite material.

[0028] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0029] The following examples use conventional instruments and equipment in the art. The experimental methods in the following examples where specific conditions are not specified are usually carried out under conventional conditions or under conditions recommended by the manufacturer. The various raw materials used in the following examples are conventional commercial products unless otherwise specified, and their specifications are conventional specifications in the art. In the specification of the present invention and the following examples, unless otherwise specified, "%" means weight percentage, "part" means weight part, and ratio means weight ratio.

[0030] Example 1 A method for preparing a neutron and gamma composite shielding material based on a solvent-free tungsten-based fluid comprises the following steps: Weigh 10 g of polyetheramine organic polymer (M2070), disperse it in 100 mL of methanol, stir it magnetically at room temperature to make it evenly mixed, then add 1.182 g (equimolar amount) of organosilane coupling agent γ-glycidyloxypropyltrimethoxysilane (KH560), transfer it to a round-bottom flask, place it in a 45°C oil bath for condensation and reflux, and obtain an organosilane-polyetheramine solution (Methanol solution of KH560-M2070); The methanol solution of KH560-M2070 obtained above was transferred to a stoppered conical flask, and 1.118 g of nano-WO3 powder was added, and magnetic stirring was performed at room temperature for 24 h to allow the reaction to be fully reacted to obtain a reaction solution; The reaction solution was dialyzed for 24 h using a dialysis bag with a molecular weight of 3500, and the water was changed every 4 h to remove the ungrafted organic polymer long chains. After the dialysis was completed, the residual solvent (deionized water, methanol) was evaporated under reduced pressure using a rotary condenser to obtain a solvent-free tungsten-based fluid (WO3@KH560-M2070). Prepare a tetrahydrofuran solution with a mass percentage of 15% TPU: weigh TPU particles and dissolve them in the tetrahydrofuran solution, add a magnetic stirrer to mix them evenly; Prepare a tetrahydrofuran solution of WO3@KH560-M2070 with a mass percentage of 15% by weight: weigh WO3@KH560-M2070 and dissolve it in the tetrahydrofuran solution, add a magnetic stirrer to mix it evenly; Preparation of casting solution: Mix the prepared 15% WO3@KH560-M2070 tetrahydrofuran solution and 15% TPU tetrahydrofuran solution in a mass ratio of 1:9, add a magnetic particle, stir at room temperature for 2 hours, and ultrasonicate for 2 hours to prepare the required casting solution; The casting machine was turned on for heating, and the polytetrafluoroethylene film was laid flat on the surface of the casting machine, and vacuum was drawn. The speed of the casting machine was adjusted to 10 mm / s, and the film thickness was 0.02 mm. The casting liquid was dropped on the polytetrafluoroethylene film, and the scraper was made to scrape the casting liquid at a uniform speed to form a TPU modified film with uniform thickness, and dried in an oven at 40°C to obtain a solvent-free tungsten-based fluid / TPU composite material; The solvent-free tungsten-based fluid / TPU composite material obtained in this embodiment takes thermoplastic polyurethane (TPU) as a matrix and is doped with surface-modified nano WO3 functional particles as neutron and gamma shielding agents. Based on the total mass of the neutron gamma composite shielding material, the components of the composite shielding material are: nano WO3: 9.91%, thermoplastic polyurethane: 90.09%.

[0031] Example 2 A method for preparing a neutron and gamma composite shielding material based on a solvent-free tungsten-based fluid comprises the following steps: Weigh 10 g of polyetheramine organic polymer (M2070), disperse it in 80 mL of methanol, stir it magnetically at room temperature to make it evenly mixed, then add 1.182 g (equimolar amount) of organosilane coupling agent γ-glycidyloxypropyltrimethoxysilane (KH560), transfer it to a round-bottom flask, place it in a 50°C oil bath for condensation and reflux, and obtain an organosilane-polyetheramine solution (Methanol solution of KH560-M2070); The methanol solution of KH560-M2070 obtained above was transferred to a stoppered conical flask, and 1.400 g of nano-WO3 powder was added, and magnetic stirring was performed at room temperature for 12 h to fully react to obtain a reaction solution; The reaction solution was dialyzed for 36 h using a dialysis bag with a molecular weight of 3500, and the water was changed every 5 h to remove the ungrafted organic polymer long chains. After the dialysis was completed, the residual solvent (deionized water, methanol) was evaporated under reduced pressure using a rotary condenser to obtain a solvent-free tungsten-based fluid (WO3@KH560-M2070). Prepare a tetrahydrofuran solution with a mass percentage of 20% TPU: weigh TPU particles and dissolve them in the tetrahydrofuran solution, add a magnetic stirrer to mix them evenly; Prepare a tetrahydrofuran solution of WO3@KH560-M2070 with a mass percentage of 20% by weight: weigh WO3@KH560-M2070 and dissolve it in the tetrahydrofuran solution, add a magnetic stirrer to mix it evenly; Preparation of casting solution: Mix the prepared 20% WO3@KH560-M2070 tetrahydrofuran solution and 20% TPU tetrahydrofuran solution in a mass ratio of 2:8, add a magnetic bar, stir at room temperature for 3 hours, and ultrasonicate for 2 hours to prepare the required casting solution; The casting machine was turned on for heating, and the polytetrafluoroethylene film was spread flat on the surface of the casting machine, and vacuum was drawn. The speed of the casting machine was adjusted to 12 mm / s, and the film thickness was 0.05 mm. The casting liquid was dropped on the polytetrafluoroethylene film, and the scraper was made to scrape the casting liquid at a uniform speed to form a TPU modified film with uniform thickness, which was dried in an oven at 45°C to obtain a solvent-free tungsten-based fluid / TPU composite material. The solvent-free tungsten-based fluid / TPU composite material obtained in this embodiment takes thermoplastic polyurethane (TPU) as a matrix and is doped with surface-modified nano WO3 functional particles as neutron and gamma shielding agents. Based on the total mass of the neutron gamma composite shielding material, the components of the composite shielding material are: nano WO3: 20.00%, thermoplastic polyurethane: 80.00%.

[0032] Example 3 A method for preparing a neutron and gamma composite shielding material based on a solvent-free tungsten-based fluid comprises the following steps: Weigh 10 g of polyetheramine organic polymer (M2070), disperse it in 100 mL of methanol, stir it magnetically at room temperature to make it evenly mixed, then add 1.182 g (equimolar amount) of organosilane coupling agent γ-glycidyloxypropyltrimethoxysilane (KH560), transfer it to a round-bottom flask, place it in a 45°C oil bath for condensation and reflux, and obtain an organosilane-polyetheramine solution (Methanol solution of KH560-M2070); The methanol solution of KH560-M2070 obtained above was transferred to a stoppered conical flask, and 2.796 g of nano-WO3 powder was added, and magnetic stirring was performed at room temperature for 24 h to allow the reaction to be fully reacted to obtain a reaction solution; The reaction solution was dialyzed for 48 h using a dialysis bag with a molecular weight of 3500, and the water was changed every 4 h to remove the ungrafted organic polymer long chains. After the dialysis was completed, the residual solvent (deionized water, methanol) was evaporated under reduced pressure using a rotary condenser to obtain a solvent-free tungsten-based fluid (WO3@KH560-M2070). Prepare a tetrahydrofuran solution with a mass percentage of 25% TPU: weigh TPU particles and dissolve them in the tetrahydrofuran solution, add a magnetic stirrer to mix them evenly; Prepare a tetrahydrofuran solution of WO3@KH560-M2070 with a mass percentage of 25% by weight: weigh WO3@KH560-M2070 and dissolve it in the tetrahydrofuran solution, add a magnetic stirrer to mix it evenly; Preparation of casting solution: Mix the prepared 25% WO3@KH560-M2070 tetrahydrofuran solution and 25% TPU tetrahydrofuran solution in a mass ratio of 3:7, add a magnetic bar, stir at room temperature for 4 hours, and ultrasonicate for 2 hours to prepare the required casting solution; The casting machine was turned on for heating, and the polytetrafluoroethylene film was laid flat on the surface of the casting machine, and vacuum was drawn. The casting machine speed was adjusted to 15 mm / s, and the film thickness was 8 mm. The casting liquid was dropped on the polytetrafluoroethylene film, and the scraper was made to scrape the casting liquid at a uniform speed to form a TPU modified film with uniform thickness, which was dried in an oven at 45°C to obtain a solvent-free tungsten-based fluid / TPU composite material. The solvent-free tungsten-based fluid / TPU composite material obtained in this embodiment is based on thermoplastic polyurethane (TPU) and doped with surface-modified nano WO3 functional particles as neutron and gamma shielding agents. Based on the total mass of the neutron gamma composite shielding material, the composition of the composite shielding material is: nano WO3: 30.07%, thermoplastic polyurethane: 69.93%.

[0033] Example 4 A method for preparing a neutron and gamma composite shielding material based on a solvent-free tungsten-based fluid comprises the following steps: Weigh 10 g of polyetheramine organic polymer (M2070), disperse it in 90 mL of methanol, stir it magnetically at room temperature to make it evenly mixed, then add 1.182 g (equimolar amount) of organosilane coupling agent γ-glycidyloxypropyltrimethoxysilane (KH560), transfer it to a round-bottom flask, place it in a 55°C oil bath for condensation and reflux, and obtain an organosilane-polyetheramine solution (Methanol solution of KH560-M2070); The methanol solution of KH560-M2070 obtained above was transferred to a stoppered conical flask, and 1.864 g of nano-WO3 powder was added, and magnetic stirring was performed at room temperature for 18 h to allow the reaction to be fully reacted to obtain a reaction solution; The reaction solution was dialyzed for 24 h using a dialysis bag with a molecular weight of 4000, and the water was changed every 4 h to remove the ungrafted organic polymer long chains. After the dialysis was completed, the residual solvent (deionized water, methanol) was evaporated under reduced pressure using a rotary condenser to obtain a solvent-free tungsten-based fluid (WO3@KH560-M2070). Prepare a tetrahydrofuran solution with a mass percentage of 30% TPU: weigh TPU particles and dissolve them in the tetrahydrofuran solution, add a magnetic stirrer to mix them evenly; Prepare a tetrahydrofuran solution of WO3@KH560-M2070 with a mass percentage of 30% by weight: weigh WO3@KH560-M2070 and dissolve it in the tetrahydrofuran solution, add a magnetic stirrer to mix it evenly; Preparation of casting solution: Mix the prepared 30% tetrahydrofuran solution of WO3@KH560-M2070 and 30% tetrahydrofuran solution of TPU in a mass ratio of 4:6, add a magnetic particle, stir at room temperature for 2 hours, and ultrasonicate for 3 hours to prepare the required casting solution; The casting machine was turned on for heating, and the polytetrafluoroethylene film was laid flat on the surface of the casting machine, and vacuum was drawn. The speed of the casting machine was adjusted to 18 mm / s, and the film thickness was 10 mm. The casting liquid was dropped on the polytetrafluoroethylene film, and the scraper was made to scrape the casting liquid at a uniform speed to form a TPU modified film with uniform thickness, which was dried in an oven at 55°C to obtain a solvent-free tungsten-based fluid / TPU composite material. The solvent-free tungsten-based fluid / TPU composite material obtained in this embodiment takes thermoplastic polyurethane (TPU) as a matrix and is doped with surface-modified nano WO3 functional particles as neutron and gamma shielding agents. Based on the total mass of the neutron gamma composite shielding material, the components of the composite shielding material are: nano WO3: 40.12%, thermoplastic polyurethane: 59.88%.

[0034] Example 5 A method for preparing a neutron and gamma composite shielding material based on a solvent-free tungsten-based fluid comprises the following steps: Weigh 10 g of polyetheramine organic polymer (M2070), disperse it in 110 mL of methanol, stir it magnetically at room temperature to make it evenly mixed, then add 1.182 g (equimolar amount) of organosilane coupling agent γ-glycidyloxypropyltrimethoxysilane (KH560), transfer it to a round-bottom flask, place it in a 60°C oil bath pot for condensation and reflux, and obtain an organosilane-polyetheramine solution (Methanol solution of KH560-M2070); The methanol solution of KH560-M2070 obtained above was transferred to a stoppered conical flask, and 2.236 g of nano-WO3 powder was added, and magnetic stirring was performed at room temperature for 24 h to allow the reaction to be fully reacted to obtain a reaction solution; The reaction solution was dialyzed for 48 h using a dialysis bag with a molecular weight of 4000, and the water was changed every 6 h to remove the ungrafted organic polymer long chains. After the dialysis was completed, the residual solvent (deionized water, methanol) was evaporated under reduced pressure using a rotary condenser to obtain a solvent-free tungsten-based fluid (WO3@KH560-M2070). Prepare a tetrahydrofuran solution with a mass percentage of 15% TPU: weigh TPU particles and dissolve them in the tetrahydrofuran solution, add a magnetic stirrer to mix them evenly; Prepare a tetrahydrofuran solution of WO3@KH560-M2070 with a mass percentage of 15% by weight: weigh WO3@KH560-M2070 and dissolve it in the tetrahydrofuran solution, add a magnetic stirrer to mix it evenly; Preparation of casting solution: Mix the prepared 15% WO3@KH560-M2070 tetrahydrofuran solution and 15% TPU tetrahydrofuran solution in a mass ratio of 1:1, add a magnetic bar, stir at room temperature for 2 hours, and ultrasonicate for 3 hours to prepare the required casting solution; The casting machine was turned on for heating, and the polytetrafluoroethylene film was laid flat on the surface of the casting machine, and vacuum was drawn. The speed of the casting machine was adjusted to 20 mm / s, and the film thickness was 0.15 mm. The casting liquid was dropped on the polytetrafluoroethylene film, and the scraper was made to scrape the casting liquid at a uniform speed to form a TPU modified film with uniform thickness, which was dried in an oven at 60°C to obtain a solvent-free tungsten-based fluid / TPU composite material. The solvent-free tungsten-based fluid / TPU composite material obtained in this embodiment takes thermoplastic polyurethane (TPU) as a matrix and is doped with surface-modified nano WO3 functional particles as neutron and gamma shielding agents. Based on the total mass of the neutron gamma composite shielding material, the components of the composite shielding material are: nano WO3: 50.00%, thermoplastic polyurethane: 50.00%.

[0035] Example 6 Different from Example 5, in this embodiment, the mass ratio of nano WO3 powder to organosilane-polyetheramine solution is 1:10; the mass percentage of thermoplastic polyurethane in the tetrahydrofuran solution of thermoplastic polyurethane is 30%, and the remaining steps are the same as in Example 5.

[0036] Figure 1 This is a physical picture of the neutron and gamma composite shielding material based on solvent-free tungsten-based fluid prepared by the present invention. Figure 2 This is a SEM image of the neutron and gamma composite shielding material based on the solvent-free tungsten-based fluid prepared by the present invention, wherein the mass ratio of the solvent-free tungsten-based fluid to TPU is 3:7. It can be seen from the figure that the solvent-free tungsten-based fluid significantly improves the easy agglomeration problem of WO3 and has good dispersion in TPU. Figure 3 The performance image of the neutron and gamma composite shielding material based on the solvent-free tungsten-based fluid prepared by the present invention shows that as the content of the solvent-free tungsten-based fluid increases, the tensile properties of the TPU composite material show a trend of first increasing and then decreasing, reaching a peak value of 69.15Mpa when the addition amount is 30%, which is 1.9 times that of pure TPU; as the content of the solvent-free tungsten-based fluid increases, the elongation at break of the TPU composite material shows a trend of first increasing and then decreasing, reaching a peak value when the addition amount is 20%, and the elongation at break is 1195%, which is 2.5 times that of pure TPU. All of these fully prove the excellence of the solvent-free tungsten-based fluid in enhancing the mechanical properties of TPU.

[0037] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A neutron and gamma composite shielding material based on solvent-free tungsten-based fluid, characterized in that: The neutron and gamma composite shielding material based on solvent-free tungsten-based fluid uses nano WO3 powder as a neutron and gamma ray absorber and thermoplastic polyurethane as a matrix material, and the WO3 powder is added to the matrix material in the form of solvent-free tungsten-based fluid; Measured by mass percentage, the components of the neutron and gamma composite shielding material based on solvent-free tungsten-based fluid are: 9.91-50% of nano WO3 powder and 50-90.09% of thermoplastic polyurethane.

2. The method for preparing a neutron and gamma composite shielding material based on a solvent-free tungsten-based fluid as claimed in claim 1, characterized in that: The following steps are involved: The organic silane-polyetheramine solution and the nano-WO3 powder are mixed and reacted to obtain a reaction solution; The reaction solution is dialyzed and rotary evaporated in sequence to obtain a solvent-free tungsten-based fluid; The tetrahydrofuran solution of the solvent-free tungsten-based fluid and the tetrahydrofuran solution of the thermoplastic polyurethane are mixed, and then magnetic stirring and ultrasonic treatment are performed in sequence to obtain a casting solution; The casting liquid is dropped onto a polytetrafluoroethylene film for film-forming treatment to obtain a neutron and gamma composite shielding material based on a solvent-free tungsten-based fluid.

3. The method for preparing a neutron and gamma composite shielding material based on a solvent-free tungsten-based fluid according to claim 2, characterized in that: The preparation method of the organosilane-polyetheramine solution is: The polyetheramine organic polymer is dispersed in methanol, magnetically stirred, and then γ-glycidyloxypropyltrimethoxysilane is added, followed by condensation and reflux to obtain an organic silane-polyetheramine solution; The mass ratio of the polyetheramine organic polymer to methanol is 1:(7-10); The γ-glycidyloxypropyltrimethoxysilane and the polyetheramine organic high molecular polymer are in equimolar amounts; The condensation reflux is carried out in an oil bath, and the temperature of the oil bath is 45-60°C.

4. The method for preparing a neutron and gamma composite shielding material based on a solvent-free tungsten-based fluid according to claim 2, characterized in that: The mass ratio of the nano WO3 powder to the organosilane-polyetheramine solution is 1:(4-10); The dialysis conditions are as follows: the dialysis time is 24 to 60 hours, and the water is changed every 4 to 6 hours during the dialysis process.

5. The method for preparing a neutron and gamma composite shielding material based on a solvent-free tungsten-based fluid according to claim 2, characterized in that: The tetrahydrofuran solution of thermoplastic polyurethane is prepared by mixing thermoplastic polyurethane particles and tetrahydrofuran solution; the mass percentage of thermoplastic polyurethane in the tetrahydrofuran solution of thermoplastic polyurethane is 15% to 30%; The tetrahydrofuran solution of the solvent-free tungsten-based fluid is prepared by mixing the solvent-free tungsten-based fluid and the tetrahydrofuran solution; the mass percentage of the solvent-free tungsten-based fluid in the tetrahydrofuran solution of the solvent-free tungsten-based fluid is 15% to 30%.

6. The method for preparing a neutron and gamma composite shielding material based on a solvent-free tungsten-based fluid according to claim 5, characterized in that: The mass ratio of the solvent-free tungsten-based fluid to the thermoplastic polyurethane in the casting solution is (1:9) to (1:1).

7. The method for preparing a neutron and gamma composite shielding material based on a solvent-free tungsten-based fluid according to claim 2, characterized in that: The magnetic stirring time is 2 to 6 hours; the ultrasonic treatment time is 2 to 6 hours.

8. The method for preparing a neutron and gamma composite shielding material based on a solvent-free tungsten-based fluid according to claim 2, characterized in that: The specific steps of the film forming process are: The polytetrafluoroethylene film is spread flat on the surface of the casting machine, vacuum is drawn, the speed of the casting machine and the film thickness are adjusted, the casting liquid is dropped on the polytetrafluoroethylene film, and the scraper is used to scrape the casting liquid at a uniform speed, and then a neutron and gamma composite shielding material based on a solvent-free tungsten-based fluid is obtained after drying.

9. The method for preparing a neutron and gamma composite shielding material based on a solvent-free tungsten-based fluid according to claim 8, characterized in that: The temperature of the drying process is 40-60°C.

10. The method for preparing a neutron and gamma composite shielding material based on a solvent-free tungsten-based fluid according to claim 8, characterized in that: The speed of the tape casting machine is 10-20 mm / s; the film thickness is 0.02-0.15 mm.

Images