Nuclear shielding material and preparation method thereof
By embedding high atomic number metal particles on the surface of polyethersulfone hollow fibers and wrapping them with reinforcing fibers, the problem of insufficient interfacial bonding strength was solved, resulting in a high-efficiency and lightweight nuclear shielding material that improves the material's stability and mechanical properties.
Patent Information
- Application Number
- CN202511002131.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-21
- Publication Date
- 2025-11-04
AI Technical Summary
Existing nuclear shielding materials have insufficient interfacial bonding strength between heavy metals and polymer matrices, which makes heavy metals prone to detachment, affecting long-term stability and reliability. In addition, traditional materials have problems such as high toxicity, poor mechanical properties, and inconvenient construction.
Using polyethersulfone hollow fiber as the matrix, a porous structure is prepared by electrospinning, and high atomic number metal particles are embedded on its surface. Reinforcing fibers are spirally wound around the outer periphery to form a three-level gradient metal filling, which enhances the interfacial bonding force. The integral structure is formed by hot melting process.
It significantly improves the radiation attenuation efficiency of nuclear shielding materials, reduces weight, enhances the mechanical strength and stability of materials, overcomes the shortcomings of traditional materials, and achieves a balance between lightweight and efficient radiation shielding.
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Figure CN120889094A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of nuclear protection, in particular to a nuclear shielding material, especially a fiber with nuclear shielding function, and a preparation method of the nuclear shielding material. BACKGROUND
[0002] With the rapid development of global nuclear energy technology, the demand for high-efficiency radiation shielding materials in the fields of nuclear power plants, nuclear fuel reprocessing, radioactive medical treatment and nuclear waste storage is increasingly urgent. Nuclear radiation (such as nuclear radiation, X-rays, neutron flow, etc.) is extremely harmful to the human body and the environment, and the development of lightweight, high shielding performance and environmentally friendly materials has become a research focus. Traditional nuclear shielding materials are mainly high-density metals (such as lead, tungsten) and concrete, which have good radiation blocking ability, but have the disadvantages of high toxicity, poor mechanical properties, and inconvenient construction.
[0003] In recent years, research has shifted to polymer-based composites to address the limitations of traditional materials. This type of material is prepared by compounding heavy metals (such as lead, bismuth, tungsten, etc.) or functional fillers (such as barium glass, borosilicate) with a high polymer matrix (such as epoxy resin, rubber, thermoplastic), utilizing the absorption capacity of heavy metals to high-energy radiation and the molding advantages of polymers to achieve a balance between lightweight and shielding performance. For example, lead-containing polymer composites can be prepared by blending or filling, significantly reducing the density of the material; composite materials doped with light elements such as boron and lithium can also shield neutrons. However, the key to such materials lies in the interfacial bonding strength between the heavy metal and the polymer matrix. If the dispersion is uneven or the interfacial bonding is weak, the heavy metal is prone to fall off under radiation, temperature change or mechanical stress, resulting in a decrease in shielding performance or even failure.
[0004] Although existing nuclear shielding materials have made progress in lightweight and multifunctionalization, their core still relies on the physical filling or surface attachment of heavy metals. Due to the lack of efficient interfacial strengthening means, heavy metals are prone to debonding from the matrix, significantly weakening the long-term stability and reliability of the material. SUMMARY
[0005] The present application aims to overcome the shortcomings of the prior art and provide a nuclear shielding material, To achieve the above-mentioned purpose, the technical solution provided by the present application is as follows. A nuclear shielding material is made of polyether sulfone hollow fibers, the surface of the polyether sulfone hollow fibers is a porous structure, high-atomic-number metal particles are embedded on the surface of the polyether sulfone hollow fibers through an impregnation process, and an outer layer of fibers is spirally wound around the outer periphery of the polyether sulfone hollow fibers and the metal particles. The outer diameter of the polyether sulfone fiber is 150-200 μm, and the inner diameter is 50-100 μm.
[0006] Polyether sulfone belongs to aromatic thermoplastic polymer, with a glass transition temperature of 220℃, maintaining dimensional stability in the range of -50℃ to 180℃. The micron-sized porous structure constructed on its surface has a pore size of 5-20μm, formed by phase inversion method, with a porosity of up to 65%-80%, and a large specific surface area. The internal hollow structure not only realizes lightweight, but also enhances the penetration depth of subsequent metal impregnation through capillary effect. High atomic number metal particles can dissipate high-energy radiation through photoelectric effect, Compton scattering and electron pair effect, achieving good nuclear shielding effect. The outer layer of fiber, as part of the reinforcement system, is wound at a helix angle of 55°-65°, which mainly serves to improve tensile strength, and secondarily serves to weaken secondary radiation through fiber interface reflection.
[0007] As a preferred technical solution, the particle size of the metal particles includes, by weight percentage, 55-60% of metal particles with a diameter of 10-20μm, 25-30% of metal particles with a diameter of 5-10μm, and 10-20% of metal particles with a diameter of 3-10μm. The use of metal particles of different diameters through graded filling, large particles (10-20μm) as a skeleton support, provide the main shielding quality, reduce the penetration depth of high-energy radiation; medium particles (5-10μm) fill the gaps between large particles, block the escape path of secondary radiation; small particles (3-10μm) cover micron-sized pores, improve the uniformity of metal phase distribution, and avoid local shielding weak spots. The three-level gradient can make the metal filling density approach 68-72%, improving the nuclear radiation attenuation efficiency. Each type of particle is embedded in the polyether sulfone porous structure, increasing the bonding force through mechanical interlocking effect, preventing particle shedding in irradiation environment.
[0008] As a preferred technical solution, the high atomic number metal particles include at least one of zirconium, niobium, tin, barium, hafnium, tantalum, tungsten, rhenium, bismuth, and oxides thereof. Although for inert high atomic number metal particles, the nuclear shielding effect is relatively good, however, in some metal oxides, the oxygen element can increase the probability of Compton scattering, thus also having good shielding effect for medium and low energy rays.
[0009] As a preferred technical solution, the outer layer of fiber includes at least one of polyester fiber, nylon fiber, acrylic fiber, chlorofiber, spandex fiber, aramid fiber, etc. Winding at a helix angle of 55°-65° increases the axial tensile strength of the material, prevents the collapse of the hollow fiber when under pressure, and the interface reflection between fiber layers scatters electrons, tortuously changes the path of the rays, increases the interaction probability, and reduces the production of bremsstrahlung. The outer layer of fiber is also hot-melted to the polyether sulfone hollow fiber, which forms a "micro-column pinning" effect when cooling and shrinking, further fixing the metal particles on the surface of the polyether sulfone hollow fiber.
[0010] A method for preparing a nuclear shielding material, comprising the following steps: S1, electrospinning to prepare polyether sulfone hollow fibers; S2, preliminary curing of metal particles to the surface of the polyether sulfone hollow fibers in an impregnating solution containing metal particles; S3, heating the surface of the polyether sulfone hollow fibers with the metal particles cured thereon to embed the metal particles into the surface of the polyether sulfone hollow fibers; S4, winding an outer layer fiber around the periphery of the polyether sulfone hollow fibers and heating the outer layer fiber to integrate it with the polyether sulfone hollow fibers; S5, weaving the polyether sulfone hollow fibers with the polyester fibers wound thereon into a nuclear shielding material.
[0011] As a preferred technical solution, in S1: the components of the spinning solution include, by weight percentage, 22-26% polyether sulfone, 70-75% N-methyl pyrrolidone, 2-3% lithium borate, and 1-2% polyvinyl pyrrolidone; the voltage for electrospinning is 28-32kV, the flow rate of the spinning solution is 0.5-0.8mL / min, the spinning receiving distance is 10-20cm, and the spun fibers are subjected to drying treatment. Here, the spinning solution formula takes into account the forming effect and viscosity of the fibers to prevent the risk of fiber breakage or excessive viscosity causing nozzle blockage; N-methyl pyrrolidone balances the volatility of the solvent and the solubility of polyether sulfone; lithium borate increases the conductivity of the spinning solution and enhances the electric field stretching force to make the fiber diameter uniform and stable; and polyvinyl pyrrolidone is used to reduce the surface tension of the spinning solution and promote the stable formation of the hollow structure.
[0012] As a preferred technical solution, in S2: the solution of the impregnating solution is composed of an acrylate prepolymer and acetone in a weight ratio of 1:4, and the impregnation time is not less than 2 hours. The use of acetone in the impregnating solution reduces the viscosity, which is conducive to the penetration effect of the metal particles in the subsequent process, and the acrylate prepolymer provides bonding groups to achieve the preliminary fixing effect during the impregnation of the metal particles. The impregnation time is more than 2 hours to ensure the impregnation effect.
[0013] As a preferred technical solution, in S3: the polyether sulfone hollow fibers are heated to 320-340℃ in a heating device and maintained for 5-10min. The temperature window of 320-340℃ is used to match the glass transition temperature and decomposition temperature of polyether sulfone, and the heating duration ensures the embedding depth of the metal particles without causing fiber breakage due to thermal degradation of polyether sulfone. After the metal particles are embedded, cooling methods such as air cooling can be used.
[0014] As a preferred technical scheme, in the S4, the outer layer fiber is wound on the polyether sulfone hollow fiber outside the winding machine at a spindle speed of 2000-5000 rpm, the swing frequency of the guide hook is 50 Hz, the angle range of the wrapping angle is 55-65°, the tension of the polyether sulfone hollow fiber is controlled at 0.3-0.5 cN / tex, and the tension of the outer layer fiber is controlled at 0.8-1.2 cN / tex. The spindle speed is used to balance the fiber tension, and too low will cause insufficient wrapping, and too high will easily cause yarn breakage. The tension control of the polyether sulfone is used to avoid its collapse, and the relatively large tension of the outer layer fiber makes it have a certain elastic deformation, and the prestress brought by the elastic deformation is beneficial to the hot melting connection of the outer layer fiber and the polyether sulfone fiber.
[0015] As a preferred technical scheme, in the S5, on the warp knitting machine, the combing guide swing angle is set to 60-75°, the warp yarn tension is 0.4-0.6 cN / tex, and the weft yarn introduction speed is 25 m / min. The combing guide swing angle is used to control the weft knitting density. The warp yarn tension maintains the tension of the yarn in the straight state, and the weft yarn introduction speed matches the cooling crystallization kinetics rate of the subsequent hot melting composite interface of the outer layer fiber and the polyether sulfone hollow fiber.
[0016] The advantages and beneficial effects of the present application are that the three-dimensional porous matrix constructed based on the polyether sulfone hollow fiber implants high atomic number metal particles through the impregnation process, significantly improving the nuclear shielding rate. The outer layer fiber is spirally wound outside the metal particles to improve the strength of the polyether sulfone fiber. At the same time, compared with the traditional lead plate protective clothing, the weight is only half of the lead plate protective clothing when reaching the same nuclear radiation shielding rate, which makes it more convenient to wear. In addition, the impregnation and heat curing process improves the fixation effect of the metal particles on the polyether sulfone hollow fiber. BRIEF DESCRIPTION OF DRAWINGS
[0017] Figure 1 is the preparation process flow chart of the nuclear shielding material shown in the present application; Figure 2 is a cross-sectional structure schematic diagram of the nuclear shielding material shown in the present application. DETAILED DESCRIPTION
[0018] The specific embodiments of the present application will be further described below in combination with the drawings and examples. The following examples are only used to more clearly illustrate the technical solutions of the present application, and cannot be used to limit the protection scope of the present application.
[0019] Example 1: A preparation process of a nuclear shielding material, comprising the following steps: S1, electrospinning to prepare polyether sulfone hollow fiber, the spinning solution includes by weight percentage: polyether sulfone 22%, N-methyl pyrrolidone 75%, lithium borate 2%, polyvinyl pyrrolidone 1%; The parameters of the electrospinning machine are set as follows: voltage 32kV, spinning solution flow rate 0.5mL / min, spinning is collected by receiving roller, and the receiving distance is 20cm. After spinning, drying is carried out in a blast drying oven at 60℃ for 2 hours to obtain polyether sulfone hollow fiber with an outer diameter of 150μm and an inner diameter of 50μm.
[0020] S2, preliminary solidification of metal particles by immersion treatment, the immersion solution is prepared by mixing acrylate prepolymer and acetone at a weight ratio of 1:4, the polyether sulfone hollow fiber is immersed in the immersion solution containing tungsten particles, the particle size distribution of the tungsten particles is as follows: 60% of 10-20μm in diameter, 25% of 5-10μm in diameter, and 15% of 3-10μm in diameter; The solid content of the immersion solution containing tungsten particles accounts for 20% of the total mass, and the immersion is carried out at room temperature for 2 hours for preliminary solidification.
[0021] S3, heating treatment to embed metal particles into the surface of the fiber, the polyether sulfone hollow fiber with tungsten particles on the surface is dried and then transferred to a tubular heating furnace, the temperature is raised to 340℃ and maintained for 5 minutes, so that the metal particles on the surface are at least partially embedded into the porous structure of the polyether sulfone hollow fiber.
[0022] S4, spiral winding of outer layer fiber and heat bonding, on the winding machine, the spindle speed is set to 5000rpm, the guide hook oscillation frequency is 50Hz, and the wrapping angle is 65°; The tension of the polyether sulfone hollow fiber is 0.3cN / tex, and the tension of the outer layer aramid fiber is 1.2cN / tex. After spiral winding of the outer layer fiber, surface heat melting is carried out in a hot air oven at 150℃ to form a whole.
[0023] S5, on the warp knitting machine, the guide bar oscillation angle is set to 75°, the warp yarn tension is 0.6cN / tex, and the weft yarn introduction speed is 25m / min, and the nuclear shielding material is obtained by knitting.
[0024] Example 2: a preparation process of a nuclear shielding material, including the following steps: S1, electrospinning to prepare polyether sulfone hollow fiber, the spinning solution includes by weight percentage: polyether sulfone 22%, N-methyl pyrrolidone 75%, lithium borate 2%, polyvinyl pyrrolidone 1%; The parameters of the electrospinning machine are set as follows: voltage 32kV, spinning solution flow rate 0.5mL / min, spinning is collected by receiving roller, and the receiving distance is 20cm. After spinning, drying is carried out in a blast drying oven at 60℃ for 2 hours to obtain polyether sulfone hollow fiber with an outer diameter of 150μm and an inner diameter of 50μm.
[0025] S2, preliminary solidification of metal particles by impregnation treatment, the impregnation liquid is a mixture of acrylate prepolymer and acetone with a weight ratio of 1:4. The fiber is immersed in the impregnation liquid containing bismuth particles (bismuth particle size weight percentage: 55% of 10-20 μm in diameter, 30% of 5-10 μm in diameter, 15% of 3-10 μm in diameter), and the solid content of the impregnation liquid is 20%. Soak at room temperature for 2.5 hours for preliminary solidification.
[0026] S3, heat treatment to embed metal particles into the surface of the fiber, after the impregnated fiber is dried, it is moved into a muffle furnace, heated to 320℃ for 10 minutes, so that the bismuth particles are at least partially embedded into the porous structure of the fiber.
[0027] S4, spiral winding of the outer layer fiber and heat bonding, on the winding machine, the spindle speed is set to 2000 rpm, the guide hook oscillation frequency is 50 Hz, the wrapping angle is 55°; the tensile force of the polyether sulfone fiber is 0.5 cN / tex, and the tensile force of the outer layer polyester fiber is 0.8 cN / tex. After winding, it is formed by heat melting at 150℃ in an infrared heater.
[0028] S5, on the warp knitting machine, set the parameters of the warp knitting machine, the comb guide oscillation angle is 60°, the warp yarn tension is 0.4 cN / tex, and the weft yarn introduction speed is 25 m / min, and the nuclear shielding material is obtained by knitting.
[0029] Example 3: a preparation process of a nuclear shielding material, comprising the following steps: S1, electrospinning to prepare polyether sulfone hollow fiber, the spinning solution includes, by weight percentage: polyether sulfone 24%, N-methyl pyrrolidone 72%, lithium borate 2.5%, polyvinyl pyrrolidone 1.5%; the parameters of the electrospinning machine are set as follows: voltage 30 kV, spinning liquid flow rate 0.6 mL / min, spinning is collected by a receiving roller, and the receiving distance is 15 cm. After spinning, the polyether sulfone hollow fiber with an outer diameter of 180 μm and an inner diameter of 70 μm is obtained by drying at 60℃ in a blowing drying box for 2 hours.
[0030] S2, preliminary solidification of metal particles by impregnation treatment, the impregnation liquid is a mixture of acrylate prepolymer and acetone with a weight ratio of 1:4. The polyether sulfone hollow fiber is immersed in the impregnation liquid containing zirconium particles, and the particle size distribution of the zirconium particles is as follows: 58% of 10-20 μm in diameter, 26% of 5-10 μm in diameter, and 16% of 3-10 μm in diameter. The solid content of the impregnation liquid containing zirconium particles accounts for 20% of the total mass, and the preliminary solidification is carried out by soaking at room temperature for 3 hours.
[0031] S3, heat treatment to embed metal particles into the surface of the fiber, after the impregnated fiber is dried, it is moved into a muffle furnace, heated to 320℃ for 10 minutes, so that the bismuth particles are at least partially embedded into the porous structure of the fiber.
[0032] S4, spiral winding of the outer layer fiber and heat bonding, on the winding machine, the nail speed is set to 3500 rpm, the guide hook swing frequency is 50 Hz, the wrapping angle is 60°; the polyether sulfone hollow fiber tension is 0.4 cN / tex, the outer layer spandex fiber tension is 1.0 cN / tex. After the spiral winding of the outer layer fiber, the surface is heat fused to form a whole in the hot air oven at 150°C.
[0033] S5, on the warp knitting machine, the guide bar swing angle of the warp knitting machine is set to 70°, the warp yarn tension is 0.5 cN / tex, the weft yarn introduction speed is 25 m / min, and the nuclear shielding material is obtained by knitting.
[0034] Example 4: a preparation process of a nuclear shielding material, comprising the following steps: S1, electrospinning to prepare polyether sulfone hollow fiber, the spinning solution includes, by weight percentage: polyether sulfone 23%, N-methyl pyrrolidone 74%, lithium borate 2.2%, polyvinyl pyrrolidone 1.8%; the electrospinning machine parameters are set as follows: voltage 31 kV, spinning solution flow rate 0.7 mL / min, spinning is collected by receiving roller, and the receiving distance is 18 cm. After spinning, the polyether sulfone hollow fiber with an outer diameter of 160 μm and an inner diameter of 60 μm is obtained by drying in a blast drying oven at 60°C for 2 hours.
[0035] S2, preliminary solidification of metal particles by immersion treatment, the immersion solution is prepared by mixing acrylate prepolymer and acetone at a weight ratio of 1:4, the polyether sulfone hollow fiber is immersed in the immersion solution containing tin oxide particles, the particle size distribution of the tin oxide particles is as follows, by weight percentage: 57% of particles with a diameter of 10-20 μm, 28% of particles with a diameter of 5-10 μm, and 15% of particles with a diameter of 3-10 μm. The solid content of the immersion solution containing tin oxide particles accounts for 20% of the total mass, and the immersion is carried out at room temperature for 3.5 hours for preliminary solidification.
[0036] S3, heating treatment to embed metal particles into the fiber surface, the polyether sulfone hollow fiber with tin oxide particles on the surface is dried and then transferred to a tubular heating furnace, heated to 335°C for 6 minutes, so that the metal particles on the surface are at least partially embedded into the porous structure of the polyether sulfone hollow fiber.
[0037] S4, spiral winding of the outer layer fiber and heat bonding, on the winding machine, the nail speed is set to 3500 rpm, the guide hook swing frequency is 50 Hz, the wrapping angle is 60°; the polyether sulfone hollow fiber tension is 0.4 cN / tex, the outer layer spandex fiber tension is 1.0 cN / tex. After the spiral winding of the outer layer fiber, the surface is heat fused to form a whole in the hot air oven at 150°C.
[0038] S5, on the warp knitting machine, the setting of the guide bar swing angle of the warp knitting machine is 65°, the warp yarn tension is 0.45 cN / tex, the weft yarn introduction speed is 25 m / min, and the nuclear shielding material is obtained by knitting.
[0039] Embodiment 5: a preparation process of a nuclear shielding material, comprising the following steps: S1, electrostatic spinning is used to prepare polyether sulfone hollow fibers, the spinning solution comprises, by weight percentage, polyether sulfone 25%, N-methyl pyrrolidone 71%, lithium borate 2.8%, and polyvinyl pyrrolidone 1.2%; the parameters of the electrostatic spinning machine are set as follows: voltage 29 kV, spinning solution flow rate 0.55 mL / min, and the spinning is collected by a receiving roller with a receiving distance of 12 cm. After spinning, the polyether sulfone hollow fibers with an outer diameter of 190 μm and an inner diameter of 80 μm are obtained by drying in a blast drying oven at 60°C for 2 hours.
[0040] S2, the tantalum particles are preliminarily solidified by immersion treatment, the immersion liquid is prepared by mixing acrylate prepolymer and acetone at a weight ratio of 1:4, the polyether sulfone hollow fibers are immersed in the immersion liquid containing tantalum particles, the particle size distribution of the tantalum particles is as follows, by weight percentage: 59% of particles with a diameter of 10-20 μm, 27% of particles with a diameter of 5-10 μm, and 14% of particles with a diameter of 3-10 μm; the solid content of the immersion liquid containing tantalum particles accounts for 20% of the total mass, and the immersion is carried out at room temperature for 4 hours for preliminary solidification.
[0041] S3, the metal particles are embedded into the fiber surface by heat treatment, the polyether sulfone hollow fibers with tantalum particles on the surface are dried and then transferred to a tube furnace, heated to 325°C for 9 minutes, so that the metal particles on the surface are at least partially embedded into the porous structure of the polyether sulfone hollow fibers.
[0042] S4, the outer layer fibers are spirally wound and heat-bonded, on the winding machine, the setting of the nail rotating speed is 3000 rpm, the guide hook swing frequency is 50 Hz, and the wrapping angle is 62°; the polyether sulfone hollow fiber tension is 0.45 cN / tex, and the outer layer chlorofiber tension is 0.9 cN / tex. After the outer layer fibers are spirally wound, the surface is heat-fused to form a whole in a hot air oven at 150°C.
[0043] S5, on the warp knitting machine, the setting of the guide bar swing angle of the warp knitting machine is 72°, the warp yarn tension is 0.55 cN / tex, the weft yarn introduction speed is 25 m / min, and the nuclear shielding material is obtained by knitting.
[0044] Embodiment 6: a preparation process of a nuclear shielding material, comprising the following steps: S1, electrospinning to prepare polyether sulfone hollow fiber, the spinning solution includes by weight percentage: polyether sulfone 22.5%, N-methyl pyrrolidone 73.5%, lithium borate 2.7%, polyvinyl pyrrolidone 1.3%; the parameters of electrospinning machine are set as follows: voltage 32kV, spinning solution flow rate 0.65mL / min, spinning is collected by receiving roller, and the receiving distance is 14cm. After spinning, the polyether sulfone hollow fiber with an outer diameter of 170μm and an inner diameter of 90μm is obtained by drying in a blast drying oven at 60℃ for 2 hours.
[0045] S2, preliminary solidification of metal particles by immersion treatment, the immersion solution is prepared by mixing acrylate prepolymer and acetone at a weight ratio of 1:4, the polyether sulfone hollow fiber is immersed in the immersion solution containing hafnium oxide particles, the particle size distribution of the hafnium oxide particles is as follows: 56% of the particles with a diameter of 10-20μm, 29% of the particles with a diameter of 5-10μm, and 15% of the particles with a diameter of 3-10μm; the solid content of the immersion solution containing hafnium oxide particles accounts for 20% of the total mass, and the immersion is carried out at room temperature for 2.2 hours for preliminary solidification.
[0046] S3, heating treatment to embed metal particles into the surface of the fiber, the polyether sulfone hollow fiber with the surface immersed with hafnium oxide particles is dried and then transferred to a tubular heating furnace, the temperature is raised to 338℃ and maintained for 7 minutes, so that the metal particles on the surface are at least partially embedded into the porous structure of the polyether sulfone hollow fiber.
[0047] S4, spiral winding of outer layer fiber and heat bonding, on the winding machine, the nail rotation speed is set to 4000rpm, the guide hook swing frequency is 50Hz, and the wrapping angle is 63°; the tension of the polyether sulfone hollow fiber is 0.38cN / tex, and the tension of the outer layer acrylic fiber is 0.85cN / tex. After the spiral winding of the outer layer fiber, the surface is heat fused to form a whole in a hot air oven at 150℃.
[0048] S5, on the warp knitting machine, the guide bar swing angle of the warp knitting machine is set to 68°, the warp yarn tension is 0.48cN / tex, and the weft yarn introduction speed is 25m / min, and the nuclear shielding material is obtained by knitting.
[0049] Example 7: a preparation process of a nuclear shielding material, including the following steps: S1, electrospinning to prepare polyether sulfone hollow fiber, the spinning solution includes by weight percentage: polyether sulfone 22.5%, N-methyl pyrrolidone 73.5%, lithium borate 2.7%, polyvinyl pyrrolidone 1.3%; the parameters of electrospinning machine are set as follows: voltage 32kV, spinning solution flow rate 0.65mL / min, spinning is collected by receiving roller, and the receiving distance is 14cm. After spinning, the polyether sulfone hollow fiber with an outer diameter of 170μm and an inner diameter of 90μm is obtained by drying in a blast drying oven at 60℃ for 2 hours.
[0050] S2, the metal particles are preliminarily solidified by immersion treatment, the immersion liquid is prepared by mixing acrylate prepolymer and acetone at a weight ratio of 1:4, the polyether sulfone hollow fiber is immersed in the immersion liquid containing rhenium particles, the particle size distribution of the rhenium particles is 60% by weight of 10-20 μm in diameter, 25% by weight of 5-10 μm in diameter, and 15% by weight of 3-10 μm in diameter, the solid content of the immersion liquid containing the rhenium particles accounts for 20% of the overall mass, and the immersion is performed at room temperature for 2.8 hours for preliminary solidification.
[0051] S3, the metal particles are embedded into the surface of the fiber by heating treatment, the polyether sulfone hollow fiber with the surface immersed with the rhenium particles is dried and then transferred to a tubular heating furnace, the temperature is raised to 322 ℃ and maintained for 9.5 minutes, so that the metal particles on the surface are at least partially embedded into the porous structure of the polyether sulfone hollow fiber.
[0052] S4, the outer layer fiber is spirally wound and heat-bonded, on the winding machine, the nail rotation speed is set to 2500 rpm, the guide hook swing frequency is 50 Hz, and the wrapping angle is 64°; the tension of the polyether sulfone hollow fiber is 0.42 cN / tex, and the tension of the outer layer aramid fiber is 1.15 cN / tex. After the outer layer fiber is spirally wound, the surface is heat-fused at 150 ℃ in a hot air oven to form a whole.
[0053] S5, on the warp knitting machine, the guide bar swing angle of the warp knitting machine is set to 74°, the warp yarn tension is 0.52 cN / tex, and the weft yarn introduction speed is 25 m / min, and the nuclear shielding material is obtained by knitting.
[0054] Embodiment 8: a preparation process of a nuclear shielding material, comprising the following steps: S1, the polyether sulfone hollow fiber is prepared by electrospinning, the spinning solution comprises, by weight percentage, polyether sulfone 24.5%, N-methyl pyrrolidone 71.5%, lithium borate 2.6%, and polyvinyl pyrrolidone 1.4%; the parameters of the electrospinning machine are set as follows: voltage 31.5 kV, and spinning liquid flow rate 0.58 mL / min; the spinning is collected by a receiving roller with a receiving distance of 19 cm. After spinning, the polyether sulfone hollow fiber with an outer diameter of 195 μm and an inner diameter of 95 μm is obtained by drying at 60 ℃ in a blast drying oven for 2 hours.
[0055] S2, the metal particles are preliminarily solidified by immersion treatment, the immersion liquid is prepared by mixing acrylate prepolymer and acetone at a weight ratio of 1:4, the polyether sulfone hollow fiber is immersed in the immersion liquid containing rhenium particles, the particle size distribution of the rhenium particles is 60% by weight of 10-20 μm in diameter, 25% by weight of 5-10 μm in diameter, and 15% by weight of 3-10 μm in diameter, the solid content of the immersion liquid containing the rhenium particles accounts for 20% of the overall mass, and the immersion is performed at room temperature for 2.8 hours for preliminary solidification.
[0056] S3, the heat treatment makes the metal particles embedded into the surface of the fiber, the surface of the polyether sulfone hollow fiber impregnated with germanium particles is left to dry, and then transferred to a tubular heating furnace, heated to 336℃ for 6.5 minutes, so that the metal particles on the surface are at least partially embedded into the porous structure of the polyether sulfone hollow fiber.
[0057] S4, the outer layer fiber is spirally wound and heat-bonded, on the winding machine, the nail rotation speed is set to 4800 rpm, the guide hook oscillation frequency is 50 Hz, and the wrapping angle is 59°; the polyether sulfone hollow fiber tension is 0.48 cN / tex, and the outer layer spandex fiber tension is 0.95 cN / tex. After the outer layer fiber is spirally wound, the surface is heat-fused at 150℃ in a hot air oven to form a whole.
[0058] S5, on the warp knitting machine, the guide bar oscillation angle of the warp knitting machine is set to 61°, the warp yarn tension is 0.58 cN / tex, the weft yarn introduction speed is 25 m / min, and the nuclear shielding material is obtained by knitting.
[0059] Comparative Example 1: a preparation process of a nuclear shielding material: the difference from Example 1 is that the three-stage gradient tungsten particles in Example 1 are replaced by single particle size 15±2μm.
[0060] Comparative Example 2: a preparation process of a nuclear shielding material: the difference from Example 2 is that the outer layer fiber in Example 2 is omitted, and there is no corresponding heat fusion process of the outer layer fiber and the polyether sulfone hollow fiber.
[0061] Comparative Example 3: a preparation process of a nuclear shielding material: the difference from Example 3 is that the outer layer fiber and the polyether sulfone hollow fiber in Example 3 are blended and knitted, and no heat fusion and composite process is performed between them.
[0062] Comparative Example 4: a preparation process of a nuclear shielding material: the difference from Example 3 is that only normal temperature curing is performed after S2 impregnation, and the heating step of 320-340℃ is omitted.
[0063] The above examples and comparative examples were subjected to performance analysis tests, and the test results are shown in the following table. The nuclear shielding performance was tested according to ASTM E662 (standard for gamma ray shielding test) and ISO 4037 (evaluation of radiation protection materials) using a ray source irradiation method, a cobalt 60 gamma ray source was used to irradiate the sample, a detector was used to measure the penetrating radiation dose rate, and the shielding rate was calculated; the water washing resistance was tested according to AATCC TM135 (test for washability of garments), the sample was placed in a standard washing machine, a neutral detergent was used, the water temperature was 40°C, the rotation speed was 1200 rpm, and each washing lasted for 5 minutes. After 5 times of washing, the shielding rate retention rate was evaluated according to the above nuclear shielding performance test method; the mechanical strength was tested according to ASTM D882 (standard for tensile test of plastic film), a universal material testing machine was used, a tensile speed of 10 mm / min was used for loading, the maximum tensile force at the time of breaking was measured, and the tensile strength was calculated; and the weight density was calculated according to ASTM D792 (standard for determination of density of plastics) using a drainage method. The above only describes the preferred embodiments of the present application, and it should be noted that, for those skilled in the art, several improvements and refinements can be made without departing from the technical principles of the present application, and these improvements and refinements should also be considered as falling within the protection scope of the present application.
Claims
1. A nuclear shielding material, characterized in that: It is woven from polyethersulfone hollow fibers. The surface of the polyethersulfone hollow fibers has a porous structure and is embedded with metal particles with high atomic number. An outer layer of fibers is spirally wound around the outer periphery. The metal particles are embedded into the surface of the polyethersulfone hollow fibers through an impregnation process. The outer layer of fibers and the polyethersulfone hollow fibers are connected by hot-melt to form an integral structure. The outer diameter of the polyethersulfone hollow fibers is 150-200 μm and the inner diameter is 50-100 μm.
2. The nuclear shielding material according to claim 1, characterized in that: The particle size distribution of the metal particles, by weight percentage, includes: 55-60% particles with a diameter of 10-20 μm, 25-30% particles with a diameter of 5-10 μm, and 10-20% particles with a diameter of 3-10 μm.
3. The nuclear shielding material according to claim 2, characterized in that: The high atomic number metal particles are selected from at least one of germanium, zirconium, niobium, tin, barium, hafnium, tantalum, tungsten, rhenium, bismuth and their oxides.
4. The nuclear shielding material according to claim 1, characterized in that: The outer fiber is selected from at least one of polyester fiber, nylon fiber, acrylic fiber, chlorofiber fiber, spandex fiber, and aramid fiber.
5. A method for preparing a nuclear shielding material as described in any one of claims 1-4, characterized in that... Includes the following steps: S1. Preparation of polyethersulfone hollow fibers by electrospinning; S2. The hollow fiber is initially cured by immersing it in an impregnation solution containing metal particles; S3. Heat treatment causes metal particles to embed into the fiber surface; S4. The outer layer of fibers is spirally wound and thermally bonded; S5. Weave into the final shielding material.
6. The preparation method according to claim 5, characterized in that: In S1: the spinning solution comprises, by weight percentage, 22-26% polyethersulfone, 70-75% N-methylpyrrolidone, 2-3% lithium borate, and 1-2% polyvinylpyrrolidone; the electrospinning voltage is 28-32kV, the spinning solution flow rate is 0.5-0.8mL / min, the spinning receiving distance is 10-20cm, and the spun yarn is dried after spinning.
7. The preparation method according to claim 5, characterized in that: In S2: the impregnation solution is composed of acrylate prepolymer and acetone in a weight ratio of 1:4, and the impregnation time is not less than 2 hours.
8. The preparation method according to claim 5, characterized in that: In step S3: the polyethersulfone hollow fiber is heated to 320-340°C in a heating device and maintained for 5-10 minutes.
9. The preparation method according to claim 5, characterized in that: In step S4: the outer layer fiber is wound around the polyethersulfone hollow fiber on a winding machine at a spindle speed of 2000-5000 rpm, the oscillation frequency of the yarn guide hook is 50 Hz, the wrapping angle is in the range of 55-65°, the tension of the polyethersulfone hollow fiber is controlled at 0.3-0.5 cN / tex, and the tension of the outer layer fiber is controlled at 0.8-1.2 cN / tex.
10. The preparation method according to claim 5, characterized in that: In S5: On the warp knitting machine, the comb swing angle is set to 60-75°, the warp tension is set to 0.4-0.6 cN / tex, and the weft introduction speed is set to 25m / min.