Highly filled high strength high elastic fiber against ionizing radiation and its preparation method and application

Abstract

This application provides a high-filling-weight, high-strength, and high-elasticity anti-ionizing radiation fiber, its preparation method, and its application, belonging to the field of functional fiber material preparation. The method involves first dissolving rare earth nitrates and citric acid in an acidic alcoholic aqueous solution and heating and stirring to adjust the pH value, obtaining a sol. The sol undergoes a second heating treatment to obtain a gel. The gel is then aged, dried, ground, and calcined to obtain rare earth composite powder. The rare earth nitrates are a mixture of gadolinium nitrate, dysprosium nitrate, and cerium nitrate. Polyurethane is added to a mixed solution of DMF and xylene, stirred, and the rare earth composite powder is added. After stirring and degassing, a spinning solution is obtained. Nascent fibers are prepared by wet spinning using the spinning solution. The fibers are then drawn, washed, and dried to obtain the anti-ionizing radiation fiber. The anti-ionizing radiation fiber prepared in this application exhibits excellent shielding performance, mechanical properties, and air permeability.

Description

Technical Field

[0001] This invention relates to the field of functional fiber material preparation technology, specifically to a high-filling-content, high-strength, and high-elasticity anti-ionizing radiation fiber, its preparation method, and its application. Background Technology

[0002] In fields such as medical imaging diagnostics, radiotherapy, and the nuclear industry, protection against ionizing radiation is a key consideration for ensuring safe operation. Traditional radiation protection materials mostly use lead-based alloys or organic polymer composites, but these materials suffer from problems such as high density, poor flexibility, and uneven powder dispersion. Furthermore, existing technologies using rare-earth powder-containing anti-ionizing radiation fibers often encounter problems during preparation, including powder agglomeration, low fiber strength due to structural defects, and insufficient protective effect.

[0003] Chinese patent CN105839217A discloses a method for preparing radiation-resistant rare-earth polymer fibers. The method involves copolymerizing rare-earth polymers capable of absorbing or attenuating neutrons and gamma rays, followed by wet spinning to produce rare-earth polymer fibers. The radiation-resistant effect of these fibers is far superior to polymers prepared using traditional physical mixing methods. However, the rare-earth polymer fibers prepared by this method can only absorb or attenuate neutrons and gamma rays, and cannot effectively protect against X-rays. Furthermore, they cannot achieve broad-spectrum absorption of ionizing radiation of different energies (from low-energy X-rays to high-energy gamma rays), resulting in limited wide-range radiation protection.

[0004] In view of this, it is necessary to design a high-filling-content, high-strength, and high-elasticity anti-ionizing radiation fiber, as well as its preparation method and application. Summary of the Invention

[0005] In view of the technical problems existing in the background art, this application provides a high-filling-content, high-strength, and high-elasticity anti-ionizing radiation fiber, its preparation method and application, aiming to solve the technical problems that anti-ionizing radiation fibers containing rare earth powder often have powder agglomeration, low fiber strength due to defects in fiber structure, and insufficient fiber protection effect during the preparation process.

[0006] In a first aspect, embodiments of this application provide a method for preparing a high-filling-weight, high-strength, and highly elastic anti-ionizing radiation fiber, comprising the following steps:

[0007] S1, firstly, rare earth nitrates and citric acid are dissolved in an acidic alcoholic aqueous solution and heated and stirred to adjust the pH value to obtain a sol. Then, the sol is subjected to a second heating treatment to obtain a gel. Next, the gel is aged, dried, ground, and calcined to obtain rare earth composite powder. The rare earth nitrates are a mixture of gadolinium nitrate, dysprosium nitrate, and cerium nitrate.

[0008] S2, add polyurethane to a mixed solution of N,N-dimethylformamide (DMF) and xylene, stir for the first time, and after it is fully dissolved, add the rare earth composite powder obtained in step S1, stir for the second time, and then degas to obtain the spinning solution;

[0009] S3, the spinning solution obtained in step S2 is injected into the metering pump. The spinning solution is squeezed by the metering pump and sprayed out from the spinneret to enter the coagulation bath to form nascent fibers.

[0010] S4. Stretch, wash and dry the nascent fibers obtained in step S3 to obtain anti-ionizing radiation fibers.

[0011] In the technical solution of this application embodiment, rare earth composite powder is first prepared by the sol-gel method. Then, a spinning solution is prepared using polyurethane as the substrate and the rare earth composite powder as the filler. Nascent fibers are then prepared by wet spinning. Finally, after a series of post-treatments such as drawing, washing, and drying, ionizing radiation-resistant fibers are obtained. The sol-gel method enables atomic-level mixing of rare earth metal particles in a solution environment. The chelation coordination reaction between rare earth nitrates and citric acid ensures uniform distribution of rare earth elements, which is beneficial for broad-spectrum absorption of ionizing radiation of different energies. By combining multiple rare earth elements, the rare earth composite powder possesses broad-spectrum absorption capabilities and is adjustable. The selection of a mixed solution of N,N-dimethylformamide and xylene as the spinning solvent promotes the uniform dispersion and dissolution of polyurethane in the spinning solution.

[0012] Furthermore, the preparation of ionizing radiation-resistant fibers using rare-earth nitrates composed of gadolinium nitrate, dysprosium nitrate, and cerium nitrate is beneficial for constructing a radiation shielding system with a synergistic effect. In this system, Gd with a high atomic number (Z value) achieves Compton scattering and photoelectric absorption of gamma rays, while Dy with a high Z value scatters and absorbs high-energy gamma rays and X-rays. Together, they form a wide-range shielding core, providing protection from low-energy X-rays to high-energy gamma rays; while Ce, through valence equilibrium (Ce... 3+ / Ce 4+ The crystal structure of the stable rare earth composite powder is stabilized. At the same time, CeO2 has a certain absorption capacity for X-rays. Gd, Dy and Ce form a functionally complementary solid solution phase in the nanocrystal, which can improve the radiation shielding efficiency by more than 30%.

[0013] In some embodiments, in step S1, the mass ratio of gadolinium nitrate to dysprosium nitrate and cerium nitrate is (5-9):2:1; in step S1, the rare earth composite powder is spherical particles with an average particle size in the range of 60-600 nm.

[0014] In this embodiment, the spherical rare-earth composite powder facilitates uniform scattering of ionizing radiation. Compared to particles with irregular shapes, incident rays can undergo multiple refractions and absorptions on the spherical surface, thereby effectively reducing the "shielding blind zone." Furthermore, the smooth surface of the spheres and the uniform stress distribution can significantly reduce stress concentration caused by the irregular shape of the filler, preventing interfacial debonding of fibers under tensile or radiative conditions, thus improving the mechanical strength and long-term stability of the material.

[0015] In some embodiments, in step S1, the preparation step of the acidic alcohol aqueous solution is as follows: after mixing alcohol and water, the pH value of the solution is adjusted to 3-5 with nitric acid; in step S1, the mass ratio of alcohol to water in the acidic alcohol aqueous solution is 1:(1-3); in step S1, the mass ratio of citric acid to rare earth nitrate is (0.5-3):1; in step S1, the mass ratio of acidic alcohol aqueous solution to rare earth nitrate is (5-15):1.

[0016] In this embodiment, water and ethanol are used as solvents to prepare rare earth composite powder, which can realize solvent recycling and achieve a recovery rate of over 90%.

[0017] In some embodiments, in step S1, the heating and stirring time is 1-3 hours, wherein the heating temperature is 40-60°C and the stirring speed is 300-600 rpm; in step S1, adjusting the pH value refers to adjusting the pH to 6-8 using ammonia water; in step S1, the secondary heating treatment refers to continuously stirring the sol at 80-90°C until the sol loses its fluidity; in step S1, aging refers to letting the gel stand for 8-12 hours; in step S1, the drying temperature is 100-120°C and the time is 12-24 hours; in step S1, the grinding refers to wet grinding using ethanol as a medium, wherein the ball-to-material ratio is (8-10):1, the speed is 300-400 rpm, and the time is 18-24 hours; in step S1, the calcination temperature is 500-700°C and the time is 1-3 hours.

[0018] In this embodiment, compared to traditional high-temperature solid-state synthesis technology (calcination temperature ≥1200℃), the low-temperature calcination technology used in this application can effectively suppress excessive grain growth while maintaining the high specific surface area of ​​the powder. The nanoscale structure formed by low-temperature calcination can significantly increase the interaction interface between radiation particles and powder, extend the scattering path of the material, and thus enhance the absorption efficiency of radiation at different energy levels. In addition, the low-temperature synthesis environment can also induce more lattice defects in the rare earth composite powder crystals, which is beneficial to enhancing the scattering ability of low-energy γ rays.

[0019] In some embodiments, in step S2, the mass ratio of N,N-dimethylformamide to xylene in the mixed solution of N,N-dimethylformamide and xylene is (2-4):1; in step S2, the mass concentration of polyurethane in the mixed solution of N,N-dimethylformamide and xylene is 10-30%; in step S2, the mass ratio of rare earth composite powder to polyurethane is (3-9):1.

[0020] In this embodiment, by controlling the mass ratio of N,N-dimethylformamide to xylene within a specific range, the stability of the wet spinning process and the strength, porosity, and air permeability of the anti-ionizing radiation fiber are improved. Furthermore, the viscosity of the spinning solution is directly related to the polyurethane concentration. When the solution concentration is too low, the viscosity decreases, which can easily lead to problems such as "jet breakage" or excessively fine fiber diameter and insufficient strength during spinning. Conversely, when the solution concentration is too high, the viscosity increases sharply, increasing the stirring resistance and making it difficult to defoam the spinning solution, leaving residual air bubbles inside. This can lead to excessively high spinneret pressure during spinning, causing equipment blockage.

[0021] In some embodiments, in step S2, the first stirring time is 1-3 hours and the rotation speed is 300-600 rpm; in step S2, the second stirring time is 2-4 hours and the rotation speed is 200-400 rpm; in step S2, defoaming refers to placing the spinning solution in a vacuum environment and letting it stand for 1-3 hours.

[0022] In this embodiment, by controlling the mass ratio of rare earth composite powder to polyurethane solution within a suitable range, and by reasonably controlling parameters such as temperature, time, and stirring speed, it is beneficial to obtain a spinning solution with uniform composition, moderate viscosity, and good powder dispersion, thereby improving the performance of anti-ionizing radiation fibers.

[0023] In some embodiments, in step S3, the injection flow rate of the metering pump is 0.01-0.1 mL / min; in step S3, the inner diameter of the spinneret is 0.2-1.5 mm; in step S3, the coagulation bath is deionized water or a polar solvent solution, and the coagulation bath temperature is 20-40°C.

[0024] In this embodiment, the wet spinning process for preparing ionizing radiation-resistant fibers effectively avoids the localized enrichment of powder caused by gravity settling or electrostatic adsorption in traditional dry spinning, ensuring a uniform distribution of rare earth particles within the fiber. Furthermore, by rationally controlling the injection flow rate, spinneret size, coagulation bath type, and temperature, the highly efficient shielding properties of the rare earth composite powder are deeply integrated with the flexible mechanical properties of the polyurethane matrix, resulting in ionizing radiation-resistant fibers with excellent performance, uniform structure, and good mechanical properties.

[0025] In some embodiments, in step S4, the winding speed of the stretching is 3-7 m / min; the washing refers to soaking the fiber in a water tank for 1-5 hours; and the drying temperature is 50-80°C for 1-3 hours.

[0026] In this embodiment, optimizing the drawing speed promotes the full orientation and alignment of molecular chains and rare earth particles in the nascent fiber, improving the fiber's mechanical properties and structural stability. Precise control of the washing time effectively removes residual solvents, coagulation bath impurities, and loosely bonded rare earth powders from the fiber, ensuring its safety and functional stability. Setting appropriate drying temperatures and times thoroughly removes residual moisture and solvents, fixes the fiber structure, and avoids damage to the rare earth components and polyurethane matrix caused by high temperatures.

[0027] Secondly, embodiments of this application provide a method for preparing high-filling-weight, high-strength, and high-elasticity anti-ionizing radiation fiber according to the first aspect of this application. The high-filling-weight, high-strength, and high-elasticity anti-ionizing radiation fiber has a diameter of 40-500 μm. The high-filling-weight, high-strength, and high-elasticity anti-ionizing radiation fiber achieves an X-ray shielding rate of 80.73% at 100 keV and a γ-ray shielding rate of 66.74% at 660 keV. The fiber breaking strength reaches 34.84 MPa, the breaking elongation reaches 307.36%, and the air permeability reaches 401.83 mm / s.

[0028] Thirdly, this application provides an application of the above-mentioned high-filling-content, high-strength, and high-elasticity anti-ionizing radiation fiber, using the high-filling-content, high-strength, and high-elasticity anti-ionizing radiation fiber to prepare anti-ionizing radiation textiles in the field of medical protection.

[0029] In the technical solution of this application embodiment, the anti-ionizing radiation textile prepared by using high-filling, high-strength, and high-elasticity anti-ionizing radiation fibers can cover radiation protection in multiple scenarios, especially in the fields of medical protective clothing, interventional surgical protective devices, protective gear, and special work clothes. Moreover, the anti-ionizing radiation textile has the advantages of high shielding, high strength, and high comfort.

[0030] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0031] To more clearly illustrate the technical solution of this application, the accompanying drawings used in this application will be briefly described below. Obviously, the drawings described below are merely some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without any creative effort.

[0032] Figure 1 This is an optical image of the gel prepared in Example 1 of this application;

[0033] Figure 2 This is a scanning electron microscope image of the rare earth composite powder in Example 1 of this application. The left icon bar is 2 μm and the right icon bar is 500 nm.

[0034] Figure 3 This is a scanning electron microscope image of the anti-ionizing radiation fiber prepared in Example 1 of this application. The scale bar is 100 μm.

[0035] Figure 4 This is a scanning electron microscope image of the cross-section of the anti-ionizing radiation fiber prepared in Example 1 of this application, with a scale bar of 1 μm;

[0036] Figure 5 This is an optical image of the anti-ionizing radiation fiber prepared in Example 1 of this application;

[0037] Figure 6 The images show an optical physical picture of the base fabric woven from the anti-ionizing radiation fiber prepared in Example 1 of this application and an X-ray image at an incident X-ray energy of 100 KeV.

[0038] Figure 7 Optical images of finger sleeves made from the anti-ionizing radiation fiber prepared in Example 1 of this application, and X-ray images at an incident X-ray energy of 100 KeV. Detailed Implementation

[0039] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0041] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0042] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0043] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0044] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple types" refers to two or more (including two pieces).

[0045] To address the technical problems of powder agglomeration, low fiber strength due to structural defects, and insufficient protective effect in the preparation of anti-ionizing radiation fibers containing rare earth powders, this application provides a high-filling-content, high-strength, and high-elasticity anti-ionizing radiation fiber, its preparation method, and its application. Specifically, by combining multiple rare earth metals, preparing spherical rare earth composite powders through the synergistic effect of grinding and calcination, using a mixed solution of N,N-dimethylformamide and xylene as the spinning solvent, and controlling parameters such as the proportions of raw materials, preparation temperature, time, and stirring speed, an anti-ionizing radiation fiber with efficient broad-spectrum shielding, stable structure, and adjustable function is obtained.

[0046] In a first aspect, embodiments of this application provide a method for preparing a high-filling-weight, high-strength, and highly elastic anti-ionizing radiation fiber, comprising the following steps:

[0047] S1, rare earth nitrates and citric acid are first dissolved in an acidic alcoholic aqueous solution and heated and stirred to adjust the pH value to obtain a sol. The sol is then subjected to a second heating treatment to obtain a gel. The gel is then aged, dried, ground, and calcined to obtain rare earth composite powder. The rare earth nitrates are a mixture of gadolinium nitrate, dysprosium nitrate, and cerium nitrate. Gadolinium nitrate, dysprosium nitrate, and cerium nitrate all exist in the form of hexahydrate compounds.

[0048] S2, add polyurethane to a mixed solution of N,N-dimethylformamide and xylene, stir for the first time, and after it is fully dissolved, add the rare earth composite powder obtained in step S1, stir for the second time, and then degas to obtain the spinning solution.

[0049] S3, the spinning solution obtained in step S2 is injected into the metering pump. After being squeezed by the metering pump, the spinning solution is ejected from the spinneret and enters the coagulation bath to form nascent fibers.

[0050] S4. Stretch, wash and dry the nascent fibers obtained in step S3 to obtain anti-ionizing radiation fibers.

[0051] In the technical solution of this application embodiment, rare earth composite powder is first prepared by sol-gel method, then spinning solution is prepared with polyurethane as substrate and rare earth composite powder as filler, then nascent fiber is prepared by wet spinning, and finally anti-ionizing radiation fiber is obtained by a series of post-treatments such as stretching, washing and drying.

[0052] First, the sol-gel method enables atomic-level mixing of rare earth metal particles in a solution environment. The chelation coordination reaction between rare earth nitrates and citric acid ensures uniform distribution of rare earth elements, facilitating broad-spectrum absorption of ionizing radiation at different energies. This molecular-scale chemical bonding mode, unlike the mechanical grinding and mixing of traditional solid-state methods, eliminates the component segregation problem caused by micron-level particle agglomeration, ensuring atomic-level ordered arrangement of multiple elements during nanocrystal nucleation. Furthermore, this application controls the morphology and regularity of the rare earth composite powder through grinding and calcination processes. First, grinding breaks down large particles and agglomerates in the raw material to obtain a uniformly sized basic powder, providing favorable conditions for morphology reshaping during subsequent calcination. Second, high-temperature calcination utilizes the active migration of atoms at high temperatures and the principle of spontaneous reduction in surface energy to reshape particles into spherical shapes, thereby significantly improving morphological regularity. The synergistic effect of grinding and calcination not only optimizes the morphology of rare earth composite powder into spherical shape, effectively reducing particle size and optimizing particle size distribution, but also promotes crystal growth of rare earth composite powder during calcination, improves the integrity of its crystal structure, and ensures uniform distribution of rare earth elements, ultimately enhancing the radiation shielding effectiveness of rare earth composite powder.

[0053] Secondly, by combining multiple rare earth elements, the performance limitations of single rare earth elements are overcome, enabling the rare earth elements in the rare earth composite powder to exert a synergistic enhancement effect, giving the rare earth composite powder a broad-spectrum absorption capability with adjustable characteristics. By preparing ionizing radiation shielding fibers by combining gadolinium nitrate, dysprosium nitrate, and cerium nitrate, a radiation shielding system with a synergistic effect was constructed. In this system, gadolinium (Gd), with its high atomic number (Z value), mainly achieves shielding against γ-rays through Compton scattering and photoelectric absorption, while dysprosium (Dy), with its high Z value, scatters and absorbs high-energy γ-rays and X-rays. Together, they construct a broad-band shielding core, covering the protection range from low-energy X-rays to high-energy γ-rays. Cerium (Ce) achieves shielding through regulating valence equilibrium (Ce... 3+ / Ce 4 + The crystal structure of the stable rare earth composite powder is improved, and CeO2 has a certain absorption capacity for X-rays. Gd, Dy, and Ce form a functionally complementary solid solution phase in the composite nanocrystal, which can improve the radiation shielding efficiency by more than 30%.

[0054] Finally, this application promotes the uniform dispersion and dissolution of polyurethane in the spinning solution by selecting a mixed solution of N,N-dimethylformamide and xylene as the spinning solvent. N,N-dimethylformamide, a highly polar solvent, has extremely strong dissolving power and a strong solvating effect on the urethane groups of polyurethane, which promotes the full extension of polyurethane molecular chains, forming a homogeneous solution, ensuring solution stability, and reducing the risk of agglomeration. Xylene, as a non-polar solvent, has good compatibility with the hydrophobic segments in polyurethane, which is beneficial to the dissolution of polyurethane.

[0055] Furthermore, in step S1, the mass ratio of gadolinium nitrate to dysprosium nitrate and cerium nitrate is (5-9):2:1, preferably (5-7):2:1.

[0056] In the technical solution of this application embodiment, when the mass ratio of gadolinium nitrate, dysprosium nitrate and cerium nitrate changes within a certain range, the X-ray shielding efficiency, gamma-ray shielding efficiency, breaking strength, breaking elongation and fabric air permeability of the fiber will fluctuate, among which the X-ray and gamma-ray shielding efficiency changes more significantly.

[0057] Furthermore, in step S1, the mass ratio of citric acid to rare earth nitrate is (0.5-3):1, preferably 1:1.

[0058] In the technical solution of this application embodiment, the change in the mass ratio of citric acid to rare earth nitrate has little effect on the air permeability of the anti-ionizing radiation fiber, but it significantly affects its ionizing radiation shielding efficiency and tensile strength. This is because citric acid mainly forms complexes with metal ions through carboxyl and hydroxyl groups. When the citric acid content is low, the formed gel network is sparse, easily shrinks and cracks during drying, leading to powder agglomeration, which in turn increases the particle size of the rare earth composite powder and reduces the fiber's tensile strength. At the same time, powder agglomeration also reduces the radiation interaction interface, thereby reducing the scattering efficiency of ionizing radiation. Excessive citric acid content leads to excessive gel viscosity, easily encapsulating the solvent to form closed channels, resulting in residual carbon impurities after calcination, thus reducing the radiation shielding performance of the anti-ionizing radiation fiber.

[0059] Furthermore, in step S1, the rare earth composite powder consists of spherical particles with an average particle size in the range of 60-600 nm.

[0060] In the technical solution of this application embodiment, the spherical rare earth composite powder facilitates uniform scattering of ionizing radiation. Compared with particles of irregular morphology, incident rays can undergo multiple refractions and absorptions on the spherical surface, thereby effectively reducing the "shielding blind zone." Furthermore, the smooth surface and balanced stress distribution of the spheres significantly reduce stress concentration caused by irregular filler shapes, preventing interfacial debonding of fibers under tensile or radiation conditions, thus improving the material's mechanical strength and long-term stability. The synergistic effect of the spherical structure and the multi-element rare earth composite not only enhances the processing stability and process adaptability of the spinning solution but also endows the anti-ionizing radiation fiber with multiple characteristics such as high-efficiency broad-spectrum shielding, structural stability, and adjustable function.

[0061] Further, the preparation steps of the acidic alcohol aqueous solution are as follows: after mixing alcohol and water, the pH value of the solution is adjusted to 3-5 with nitric acid, preferably to 3-4. The mass ratio of alcohol to water in the acidic alcohol aqueous solution is 1:(1-3), preferably 1:(1-2).

[0062] In the technical solution of this application embodiment, water and ethanol are used as solvents to prepare rare earth composite powders, which can realize solvent recycling with a recovery rate of over 90%. Compared with the traditional molten salt method (using highly corrosive flux) or solid-phase method (high-energy-consuming crushing and grinding process), using water and ethanol as solvents avoids heavy metal ion pollution and high dust hazards, meets the strict requirements for green manufacturing in the nuclear industry, medical protective materials and other fields, and is conducive to the large-scale production of radiation shielding materials.

[0063] Further, in step S1, the mass ratio of the acidic alcohol aqueous solution to the rare earth nitrate is (5-15):1, preferably (5-10):1.

[0064] Further, in step S1, the heating and stirring time is 1-3 hours, preferably 2 hours. The heating temperature is 40-60℃, preferably 50-60℃; the stirring speed is 300-600 rpm, preferably 400-500 rpm. In step S1, adjusting the pH value refers to adjusting the pH to 6-8, preferably 7-8, using ammonia water. Preferably, ammonia water with a mass fraction of 25% is used. In step S1, the secondary heating treatment refers to continuously stirring the sol at 80-90℃ until the sol loses its fluidity. The secondary heating temperature is preferably 85-90℃. In step S1, aging refers to allowing the gel to stand for 8-12 hours, preferably 10-12 hours. In step S1, the drying temperature is 100-120℃, preferably 110-120℃; the drying time is 12-24 hours, preferably 20-24 hours. In step S1, grinding refers to wet grinding using ethanol as the medium. The grinding ball-to-material ratio is (8-10):1, preferably 8:1; the grinding speed is 300-400 rpm, preferably 400 rpm; and the grinding time is 18-24 h, preferably 24 h. In step S1, the calcination temperature is 500-700℃, preferably 600-700℃; and the calcination time is 1-3 h, preferably 2-3 h.

[0065] In the technical solution of this application embodiment, compared with the traditional high-temperature solid-state synthesis technology (calcination temperature ≥1200℃), the low-temperature calcination technology adopted in this application can effectively suppress excessive grain growth while maintaining the high specific surface area of ​​the powder. The nanoscale structure formed by low-temperature calcination can significantly increase the interaction interface between radiation particles and powder, extend the scattering path of the material, and thus enhance the absorption efficiency of radiation at different energy levels. In addition, the low-temperature synthesis environment can also induce more lattice defects in the rare earth composite powder crystals, which is beneficial to enhancing the scattering ability of low-energy γ rays.

[0066] Further, in step S2, the mass ratio of N,N-dimethylformamide to xylene in the mixed solution of N,N-dimethylformamide and xylene is (2-4):1, preferably (2-3):1.

[0067] In the technical solution of this application embodiment, by controlling the mass ratio of N,N-dimethylformamide to xylene within a specific range, the stability of the wet spinning process and the strength, porosity, and air permeability of the anti-ionizing radiation fiber are improved. This is because N,N-dimethylformamide has a strong dissolving ability for polyurethane, and its increased content accelerates the diffusion of N,N-dimethylformamide into the coagulation bath, causing polyurethane to precipitate rapidly and form a thicker skin structure. Ultimately, this leads to a decrease in the porosity and air permeability of the fiber, as well as a decrease in the molecular chain orientation and fiber crystallinity, resulting in a decrease in the fiber's breaking strength. When the polymer concentration remains constant, excessive N,N-dimethylformamide will cause the spinning solution viscosity to be too low, affecting the stability of the spinning solution during extrusion at the spinneret, leading to problems such as droplet breakage and discontinuous fiber formation, ultimately failing to produce qualified fibers. When the xylene content gradually increases, the polyurethane is not fully dissolved, and undissolved particles, gels, or stratification may appear in the spinning solution, thus affecting the uniformity of the spinning solution. The presence of undissolved polyurethane particles or weak interfacial bonding points within the fiber can easily become fracture sources during stretching, significantly reducing tensile strength and even preventing fiber formation. Furthermore, increased xylene content slows the diffusion rate of N,N-dimethylformamide into the coagulation bath, leading to a significant decrease in the coagulation rate. This, in turn, results in insufficient polymer molecular chain orientation, forming anti-ionizing radiation fibers with a loose, porous structure, thus increasing the fiber's porosity and air permeability.

[0068] Further, in step S2, the mass concentration of polyurethane in the mixed solution of N,N-dimethylformamide and xylene is 10-30%, preferably 15-25%. Even further, the polyurethane is a thermoplastic polyurethane elastomer (TPU) with a hardness of 85A.

[0069] In the technical solution of this application embodiment, the viscosity of the spinning solution is directly related to the polyurethane concentration. When the solution concentration is too low, the viscosity decreases, which can easily lead to problems such as "jet breakage" or excessively fine fiber diameter and insufficient strength during spinning. Conversely, when the solution concentration is too high, the viscosity increases sharply, the stirring resistance increases, which can easily lead to difficulty in degassing the spinning solution, leaving residual air bubbles inside, and causing excessively high spinneret pressure during spinning, resulting in equipment blockage. Therefore, only when the spinning solution concentration is appropriate can the prepared fibers have uniform diameter and good mechanical properties be ensured.

[0070] Further, in step S2, the mass ratio of rare earth composite powder to polyurethane is (3-9):1, preferably (6-9):1.

[0071] Further, in step S2, the first stirring time is 1-3 hours, preferably 1-2 hours; the stirring speed is 300-600 rpm, preferably 400-500 rpm. In step S2, the second stirring time is 2-4 hours, preferably 2-3 hours; the stirring speed is 200-400 rpm, preferably 300-400 rpm. In step S2, defoaming refers to placing the spinning solution in a vacuum environment and letting it stand for 1-3 hours, preferably 1-2 hours.

[0072] In the technical solution of this application embodiment, by controlling the mass ratio of rare earth composite powder to polyurethane solution within a suitable range, and by reasonably controlling parameters such as temperature, time and stirring speed, it is beneficial to obtain spinning solution with uniform composition, moderate viscosity and good powder dispersion, thereby improving the performance of anti-ionizing radiation fiber.

[0073] Further, in step S3, the metering pump has a flow rate of 0.01-0.1 mL / min, preferably 0.03-0.08 mL / min; the spinneret has an inner diameter of 0.2-1.5 mm, preferably 0.5-0.8 mm; the coagulation bath is deionized water or a polar solvent, and the temperature of the coagulation bath is 20-40°C, preferably 20-30°C.

[0074] In the technical solution of this application embodiment, the wet spinning process for preparing anti-ionizing radiation fibers effectively avoids the local enrichment of powder caused by gravity settling or electrostatic adsorption in traditional dry spinning, ensuring the uniform distribution of rare earth particles inside the fiber. Furthermore, by rationally controlling the injection flow rate, spinneret size, coagulation bath type, and temperature, it is beneficial to deeply integrate the highly efficient shielding characteristics of the rare earth composite powder with the flexible mechanical properties of the polyurethane matrix, resulting in anti-ionizing radiation fibers with excellent performance, uniform structure, and good mechanical properties.

[0075] Furthermore, in step S4, the winding speed of the stretching is 3-7 m / min, preferably 5-7 m / min.

[0076] In the technical solution of this application embodiment, optimizing the drawing speed can promote the full orientation and alignment of molecular chains and rare earth particles in the nascent fiber, thereby improving the mechanical properties and structural stability of the fiber. This is because when the drawing speed is slow, the tensile stress on the fiber is small, the molecular chain orientation is insufficient, the fiber crystallinity is low, and the fiber breaking strength is reduced. At the same time, a slow drawing speed will lead to an increase in fiber diameter and a corresponding increase in the pore size between fibers, resulting in increased air permeability. When the drawing speed is fast, the tensile stress on the fiber increases, promoting the high orientation of molecular chains along the fiber axis, increasing crystallinity, and significantly enhancing fiber strength. However, a fast drawing speed will also lead to a decrease in the pore size between fibers, an increase in path tortuosity, and a decrease in air permeability. If the drawing speed is too high and exceeds the fiber's bearing limit, it may also lead to fiber breakage or the generation of internal defects.

[0077] Furthermore, water washing refers to soaking the fibers in a water tank for 1-5 hours, preferably 2-3 hours.

[0078] In the technical solution of this application embodiment, precise control of the washing time can effectively remove residual solvents, coagulation bath impurities and unbonded rare earth powders from the fiber, ensuring the safety and functional stability of the fiber.

[0079] Furthermore, the drying temperature is 50-80°C, preferably 70-80°C; the drying time is 1-3 hours, preferably 2-3 hours.

[0080] In the technical solution of this application embodiment, setting a reasonable drying temperature and drying time can not only thoroughly remove residual moisture and solvents in the fiber and fix the fiber structure, but also avoid damage to rare earth components and polyurethane matrix caused by high temperature environment.

[0081] Secondly, embodiments of this application provide a method for preparing high-filling-weight, high-strength, and high-elasticity anti-ionizing radiation fiber according to the first aspect of this application. The high-filling-weight, high-strength, and high-elasticity anti-ionizing radiation fiber has a diameter of 40-500 μm. The high-filling-weight, high-strength, and high-elasticity anti-ionizing radiation fiber achieves a shielding rate of 80.73% against X-rays at 100 keV and a shielding rate of 66.74% against γ-rays at 660 keV. The fiber breaking strength reaches 34.84 MPa, the breaking elongation reaches 307.36%, and the air permeability reaches 401.83 mm / s.

[0082] Thirdly, embodiments of this application provide an application of the aforementioned high-filling-weight, high-strength, and high-elasticity anti-ionizing radiation fiber, using the high-filling-weight, high-strength, and high-elasticity anti-ionizing radiation fiber to prepare anti-ionizing radiation textiles.

[0083] In the technical solution of this application embodiment, the anti-ionizing radiation textile prepared by using high-filling, high-strength, and high-elasticity anti-ionizing radiation fibers can cover radiation protection in multiple scenarios, especially in the fields of medical protective clothing, interventional surgical protective devices, protective gear, and special work clothes. Moreover, the anti-ionizing radiation textile has the advantages of high shielding, high strength, and high comfort.

[0084] The following are some specific embodiments. It should be noted that the embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they shall be performed in accordance with the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0085] Example 1

[0086] Example 1 provides a method for preparing a high-filling-weight, high-strength, and high-elasticity anti-ionizing radiation fiber, comprising the following steps:

[0087] S1, weigh out 70g gadolinium nitrate, 20g dysprosium nitrate, 10g cerium nitrate, and 100g citric acid respectively, and add them sequentially to 800g of acidic alcoholic aqueous solution (pH=4, m 乙醇 :m 去离子水 In a solution of ethanol (1:2), the mixture was stirred with a glass rod until completely dissolved, then heated to 60°C and stirred at 500 rpm for 2 hours. Next, 25% ammonia solution was slowly added dropwise until the pH reached 8, yielding a sol. The sol was then subjected to a second heating treatment: the temperature was increased to 90°C, and the mixture was stirred continuously at 500 rpm until it lost its fluidity, yielding a gel. The gel was then allowed to stand for 12 hours, followed by drying in a 110°C oven for 24 hours. After drying, it was wet-milled using a planetary ball mill with ethanol as the medium, a ball-to-powder ratio of 8:1, a milling speed of 400 rpm, and a grinding time of 24 hours. Finally, the milled sol was calcined at 700°C for 3 hours to obtain rare earth composite powder.

[0088] S2, at room temperature, first mix 60g of N,N-dimethylformamide with 20g of xylene to obtain a mixed solution. Then, add 20g of polyurethane (TPU, hardness 85A) to the mixed solution and stir for the first time at 400rpm for 2 hours. After complete dissolution, add 180g of the rare earth composite powder obtained in step S1 and stir for the second time at 300rpm for 3 hours. Finally, vacuum the solution in a vacuum drying oven for 1 hour for degassing to obtain the spinning solution.

[0089] S3. Inject the spinning solution obtained in step S3 into the metering pump, adjust the injection flow rate of the metering pump to 0.05 mL / min, select a spinneret with an inner diameter of 0.5 mm, use deionized water as the coagulation bath, and set the temperature to 25°C. Turn on the metering pump, and the solution will be squeezed by the metering pump and ejected from the spinneret into the coagulation bath to form nascent fibers.

[0090] S4. Collect the fibers at a winding speed of 5 m / min, then soak them in pure water for 2 hours, and finally place them in a drying oven to dry for 3 hours at a temperature of 80°C to obtain the anti-ionizing radiation fiber.

[0091] Please see Figure 1 The image shown is an optical image of the gel prepared in Example 1 of this application. As can be seen, the gel is white and opaque, with a uniform texture and a certain degree of toughness.

[0092] Please see Figure 2 The image shown is a scanning electron microscope image of the rare earth composite powder prepared in Example 1 of this application. The left graph shows a bar of 2 μm, and the right graph shows a bar of 500 nm. It can be seen that the size of the rare earth composite powder is in the nanometer range (100-300 nm), and the particle shape is mostly spherical with a relatively smooth surface.

[0093] Please see Figure 3 The image shown is a scanning electron microscope image of the anti-ionizing radiation fiber prepared in Example 1 of this application, with a scale bar of 100 μm. It can be seen that the anti-ionizing radiation fiber has a diameter of approximately 200 μm, an uneven surface with obvious rough texture, and this rough surface structure helps to increase the specific surface area of ​​the fiber. Figure 4 The scanning electron microscope (SEM) image of the cross-section of the fiber used for shielding against ionizing radiation (scale bar: 1 μm) shows that the rare-earth composite powder is uniformly dispersed in the polyurethane substrate without significant agglomeration. This distribution characteristic is beneficial for increasing the specific surface area, avoiding the formation of weak penetration zones due to local density inhomogeneity, and allowing multi-scale particles to synergistically expand the energy coverage range, thereby enhancing the absorption and scattering probability of X-rays and improving X-ray shielding effectiveness. Furthermore, the uniformly dispersed particles in the composite system can more evenly transfer stress, which helps reduce stress concentration caused by particle agglomeration, thus improving the mechanical strength, flexibility, and processability of the shielding material.

[0094] Please see Figure 5 The image shown is an optical photograph of the anti-ionizing radiation fiber prepared in Example 1 of this application. It can be seen that the anti-ionizing radiation fiber prepared in Example 1 is pale yellow and has a uniform fiber thickness, indicating good spinning stability.

[0095] Please see Figure 6 The image shown is an optical photograph of the base fabric woven from the anti-ionizing radiation fiber prepared in Example 1 of this application, and an X-ray image at an incident X-ray energy of 100 KeV. Please refer to [link to image]. Figure 7 The image shown is an optical photograph of a finger sleeve made from the anti-ionizing radiation fiber prepared in Example 1 of this application, and an X-ray image at an incident X-ray energy of 100 KeV. Through... Figure 6 and Figure 7 As can be seen, the anti-ionizing radiation fiber prepared in Example 1 appears bright white in X-ray images, indicating that the anti-ionizing radiation fiber has a strong shielding ability against X-rays and an excellent anti-ionizing radiation effect.

[0096] Examples 2-3 and Comparative Examples 1-5

[0097] The difference between Examples 2-3 and Comparative Examples 1-5 and Example 1 is that the mass ratio of gadolinium nitrate to dysprosium nitrate and cerium nitrate in step S1 is different, as shown in Table 1. The rest is the same as in Example 1 and will not be repeated here.

[0098] The anti-ionizing radiation fibers prepared in Examples 1-3 and Comparative Examples 1-5 were tested as follows:

[0099] (1) Ionizing radiation shielding performance test: The prepared anti-ionizing radiation fiber was woven into a sample with a length × width of 20cm × 20cm and a basis weight of 2kg / m 2 Radiation protection tests were conducted according to the methods published in standard Q / 719J 131-2018 - "Test Method for Shielding Performance of Ionizing Radiation Protection Materials", and the shielding rate was calculated. The incident energy of X-rays was 100 KeV, and the incident energy of gamma rays was 660 KeV.

[0100] (2) Breaking strength test: The tensile strength (also known as breaking strength) of the fiber at break shall be tested according to the method disclosed in GB / T 14344-2022 "Test Method for Tensile Properties of Chemical Fiber Filaments", and the test shall be repeated ≥50 times.

[0101] (3) Breaking elongation test: The breaking elongation of the fiber is tested according to the method disclosed in FZ / T 50006-2013 "Test Method for Tensile Properties of Spandex Filament". At least 20 samples are tested and the average value is taken.

[0102] (4) Air permeability test: The prepared anti-ionizing radiation fiber was processed by needle punching, spunbonding and other processes to prepare a weight of 2 kg / m 2 The nonwoven fabric was cut into samples with a thickness of 3mm and a length × width of 10cm × 10cm. The air permeability was tested according to the method published in GB / T5453-1997 "Textiles - Determination of Air Permeability of Fabrics", and the air permeability rate was calculated. This air permeability rate is the original average air permeability rate.

[0103] All subsequent examples and comparative examples of ionizing radiation shielding fibers prepared using the methods described above were tested for their ionizing radiation shielding performance, breaking strength, elongation at break, and air permeability. The testing conditions were identical for all subsequent examples and comparative examples, and the samples prepared from the ionizing radiation shielding fibers and the nonwoven fabrics had the same basis weight per square meter.

[0104] The performance of the anti-ionizing radiation fibers prepared in Examples 1-3 and Comparative Examples 1-5 is shown in Table 1.

[0105] Table 1. Performance of the anti-ionizing radiation fibers prepared in Examples 1-3 and Comparative Examples 1-5

[0106]

[0107] As shown in Table 1, when the mass ratio of gadolinium nitrate, dysprosium nitrate, and cerium nitrate varies within a certain range, the X-ray shielding efficiency, gamma-ray shielding efficiency, breaking strength, breaking elongation, and fabric air permeability of the fiber all fluctuate, with the X-ray and gamma-ray shielding efficiencies showing the most significant changes. It can be observed that the absorption and shielding performance of the three-element composite element for X-rays and gamma rays is superior to that of a single element. This advantage stems from the dual effects of complementary absorption ranges and synergistic absorption mechanisms. A single element can only form a strong absorption peak at its own K absorption edge (a specific energy), resulting in a significant decrease in absorption efficiency for rays in other energy ranges and a clear shielding blind zone. However, by combining gadolinium, dysprosium, and cerium, the limitations of a single element can be eliminated through the aforementioned complementary and synergistic effects, thereby achieving improved shielding performance across the entire energy range. Furthermore, increasing the mass ratio of gadolinium nitrate makes the gamma-ray shielding function of gadolinium in the fiber more significant, significantly improving the photoelectric effect and Compton scattering efficiency, and thus enhancing the gamma-ray shielding efficiency. At the same time, increasing the gadolinium nitrate mass ratio will reduce the relative content of dysprosium nitrate and cerium nitrate. Both dysprosium and cerium have an absorption effect on X-rays, and their relative content will lead to a decrease in X-ray shielding efficiency.

[0108] Examples 4-6 and Comparative Example 6

[0109] The difference between Examples 4-6 and Comparative Example 6 and Example 1 is that the mass ratio of citric acid to rare earth nitrate is different in step S1, as shown in Table 2. The rest is the same as in Example 1 and will not be repeated here.

[0110] The ionizing radiation protection performance, breaking strength, and air permeability of the anti-ionizing radiation fibers prepared in Examples 4-6 and Comparative Example 6 were tested. The test results are shown in Table 2.

[0111] Table 2. Performance of the anti-ionizing radiation fibers prepared in Examples 4-6 and Comparative Example 6

[0112]

[0113] As shown in Table 2, changes in the mass ratio of citric acid to rare earth nitrates have little effect on the air permeability of the anti-ionizing radiation fiber, but significantly affect its ionizing radiation shielding efficiency, breaking strength, and elongation at break. This is because citric acid mainly forms complexes with metal ions through its carboxyl and hydroxyl groups. When the citric acid content is low, the chelation reaction is insufficient, resulting in a sparse gel network that is prone to shrinkage and cracking during drying, leading to powder agglomeration. This, in turn, increases the particle size of the rare earth composite powder. When the agglomerated rare earth composite powder is added to polyurethane, it becomes a stress concentration point inside the fiber. The powder cannot form a good interfacial bond with the polyurethane matrix, making it prone to breakage under stress. This not only reduces the fiber's breaking strength but also causes the fiber to lose its good flexibility, resulting in a simultaneous decrease in elongation at break. Simultaneously, powder agglomeration also reduces the radiation interaction interface, thereby reducing the scattering efficiency of ionizing radiation. When the amount of citric acid far exceeds that of rare earth nitrates, although complete chelation of rare earth ions can be achieved, it will have a significant negative impact on both the fiber's mechanical properties and radiation shielding performance. From a mechanical property perspective, excess citric acid remains in the rare-earth composite powder. These residual small organic molecules act as plasticizers in the polyurethane matrix. Initially, a small amount of residue can slightly improve fiber flexibility, leading to a temporary increase in elongation at break. However, excessive residue weakens the intermolecular forces of the polyurethane, causing a decrease in elongation at break. Simultaneously, residual citric acid also disrupts the interfacial bonding between the rare-earth composite powder and the polyurethane matrix, reducing the mechanical strength of the matrix itself and ultimately causing a continuous decline in fiber breaking strength. From a radiation shielding performance perspective, excessively high citric acid content leads to a significant increase in gel viscosity. This highly viscous gel easily encapsulates the solvent in the system, forming closed channels. During subsequent calcination, residual substances within these closed channels are difficult to remove completely, forming carbon impurities. These carbon impurities directly reduce the radiation shielding performance of the anti-ionizing radiation fiber.

[0114] Examples 7-8 and Comparative Examples 7-10

[0115] The difference between Examples 7-8 and Comparative Examples 7-10 and Example 1 is that the mass ratio of N,N-dimethylformamide to xylene in step S2 is different, as shown in Table 3. The rest is the same as in Example 1 and will not be repeated here.

[0116] The ionizing radiation shielding performance, breaking strength, and air permeability of the anti-ionizing radiation fibers prepared in Examples 7-8 were tested, and the test results are shown in Table 3. For Comparative Examples 9-10, due to excessively low or high spinning solution concentrations, fibers could not be prepared, or the prepared fibers were not meaningful for testing; therefore, no test results were obtained.

[0117] Table 3. Performance of the anti-ionizing radiation fibers prepared in Examples 7-8 and Comparative Examples 7-10

[0118]

[0119] As shown in Table 3, with the increase of the mass proportion of N,N-dimethylformamide (DMF), the properties of the fiber initially improve and then decrease. This is because N,N-dimethylformamide has a strong dissolving ability for polyurethane. When the DMF content increases, it ensures the full dissolution of polyurethane, thus forming a uniform spinning solution. At this point, the polyurethane molecular chains can fully extend and uniformly encapsulate the rare earth powder. During the solidification process, due to the slow rate of miscibility between the solvent and deionized water, no obvious defects such as voids or powder agglomeration are generated inside the fiber. The molecular chains are tightly bonded, and the interfacial force between the rare earth powder and the matrix is ​​strong. During stretching, stress can be effectively transferred, and the molecular chains can also achieve large deformation through segment sliding, ultimately increasing the fiber's breaking strength and breaking elongation simultaneously. However, in this case, it is difficult to form significant micropores inside the fiber, resulting in a dense overall structure, which leads to a decrease in porosity and air permeability.

[0120] If the DMF content is too high, the viscosity of the spinning solution will be too low. This will not only reduce the orientation of the polyurethane molecular chains and the crystallinity of the fiber, thus reducing the breaking strength and elongation at break, but also affect the stability of the spinning solution extruded from the spinneret, which can easily lead to problems such as droplet breakage and discontinuous fiber formation, ultimately making it impossible to produce qualified fiber products.

[0121] Conversely, due to xylene's insufficient solubility for polyurethane, as the mass percentage of xylene gradually increases, polyurethane may experience incomplete dissolution, leading to undissolved particles, gels, or stratification in the spinning solution, thus disrupting its uniformity. These fibers may contain undissolved polyurethane particles or weak interfacial bonding points, which are highly susceptible to fracture during stretching, resulting in a significant decrease in tensile strength. Rare earth composite powders may also agglomerate due to uneven and insufficient dispersion, further reducing radiation shielding performance. Simultaneously, the polyurethane molecular chains cannot fully extend and break before deformation during stretching, significantly reducing elongation at break and, in severe cases, preventing successful fiber formation. However, on the other hand, increased xylene content accelerates its evaporation rate, causing a large amount of solvent to escape rapidly during solidification. This creates numerous interconnected or closed micropores within the fiber, resulting in a loose, porous structure that significantly improves porosity and air permeability.

[0122] It is evident that only when the ratio of DMF to xylene is appropriate can the fiber form a small number of uniform interconnected micropores. These interconnected micropores not only meet the basic air permeability requirements, but also do not weaken the mechanical properties due to excessive micropores, ultimately achieving the best balance between mechanical properties and air permeability.

[0123] Examples 9-10 and Comparative Examples 11-12

[0124] The difference between Examples 9-10 and Comparative Examples 11-12 and Example 1 is that the concentration of polyurethane in step S2 is different, as shown in Table 4. The rest is the same as Example 1 and will not be repeated here.

[0125] The ionizing radiation shielding properties, breaking strength, and air permeability of the anti-ionizing radiation fibers prepared in Examples 9-10 were tested, and the test results are shown in Table 4. For Comparative Examples 11-12, due to excessively low or high spinning solution concentrations, fibers could not be prepared, or the prepared fibers were not meaningful for testing; therefore, no test results were obtained.

[0126] Table 4. Performance of the anti-ionizing radiation fibers prepared in Examples 9-10 and Comparative Examples 11-12

[0127]

[0128] As shown in Table 4, when the polyurethane concentration is too low, the number of polyurethane molecular chains in the spinning solution is small, and the intermolecular entanglement is insufficient. During solidification, the sparse molecular chains are difficult to form a dense structure. Furthermore, the low concentration increases the dual diffusion rate between the solvent and the coagulation bath, resulting in a loose fiber structure with numerous interconnected micropores. Although gas can pass through these micropores rapidly, significantly increasing air permeability, the fibers are prone to breakage at weak points under stress, leading to low tensile strength. Secondly, the low concentration results in excessively large molecular chain spacing and weak bonding forces. During stretching, the molecular chains are prone to slippage or breakage, preventing effective deformation and reducing the elongation at break. Simultaneously, the viscosity of the spinning solution is directly related to the polyurethane concentration. Lower viscosity leads to poor stability of the spun fibers, making them prone to breakage or uneven diameter, and even preventing the formation of continuous fibers.

[0129] With increasing concentration, the spinning solution viscosity is suitable, the molecular chain entanglement is moderate, and the fiber exhibits a dense core-sheath structure, significantly improving tensile strength and elongation at break. However, when the polyurethane concentration is too high, the molecular chains become overcrowded, chain segment sliding is hindered, and deformation through chain segment movement is difficult during stretching, increasing fiber structural rigidity and decreasing elongation at break. Simultaneously, solvent diffusion is hindered during fiber coagulation, inhibiting macropore growth and resulting in a mixed microporous and mesoporous structure, with moderate but decreased air permeability. High concentrations also lead to excessively high spinning solution viscosity, extremely poor fluidity, and a sudden increase in spinning pressure, easily causing spinneret blockage or extrusion stream breakage. The fiber surface becomes rough and internal cracks appear, leading to a decrease in tensile strength and elongation at break. Furthermore, rare earth composite powders are difficult to disperse uniformly in the polyurethane, resulting in decreased radiation shielding performance. Secondly, high concentrations also cause the polymer in the spinning solution to become highly concentrated, making it difficult for the solvent to escape during coagulation. Only the surface solvent diffuses rapidly during coagulation to form a thin skin layer, resulting in a highly dense structure and decreased air permeability.

[0130] Examples 11-12 and Comparative Examples 13-16

[0131] The difference between Examples 11-12 and Comparative Examples 13-16 and Example 1 is that the mass ratio of rare earth composite powder to polyurethane in step S2 is different, as shown in Table 5. The rest is the same as in Example 1 and will not be repeated here.

[0132] The ionizing radiation shielding performance, breaking strength, and air permeability of the ionizing radiation shielding fibers prepared in Examples 11-12 and Comparative Examples 13-16 were tested, and the test results are shown in Table 5. Comparative Example 15, due to the absence of rare earth composite powder, had shielding efficiencies for both X-rays and gamma rays close to 0, making shielding performance testing meaningless. Comparative Example 16 had an excessively low polyurethane content, making fiber preparation impossible, and therefore no test results were available.

[0133] Table 5. Performance of the anti-ionizing radiation fibers prepared in Examples 11-12 and Comparative Examples 13-16

[0134]

[0135] As shown in Table 5, the shielding efficiency of the anti-ionizing radiation fiber increases with the increase in the mass proportion of rare earth composite powder. This is because, on the one hand, with the increase in the filling amount of rare earth composite powder, the protective component composed of Gd, Dy, and Ce inside the fiber accounts for a larger proportion, thus improving the fiber's ability to shield against ionizing radiation. On the other hand, when rare earth composite powder is uniformly dispersed as a rigid filler and embedded in the polymer matrix, appropriate addition can strengthen the matrix structure through the "stress transfer effect," thereby gradually increasing the fiber's breaking strength. The active groups such as hydroxyl groups on the surface of rare earth composite powder can combine with polyurethane molecular chains through hydrogen bonds or van der Waals forces to form nanoscale physical cross-linking points, restricting molecular chain slippage, thereby improving stress transfer efficiency and enhancing breaking strength. However, at the same time, it also inhibits the deformability of polyurethane molecular chains, severely hindering the slippage and extension of molecular chains, leading to a continuous decrease in breaking elongation. In this process, rare earth powder acts as a heterogeneous nucleation site, accelerating the phase separation of solvent and non-solvent during solidification, thereby forming more micropores and significantly improving air permeability. However, when the content of rare earth composite powder exceeds a certain threshold, particle agglomeration within the fiber intensifies, leading to an increase in internal defects and stress concentration points. These points become crack initiation zones during stretching, resulting in a decrease in fiber breaking strength. Furthermore, excessively dense particles can clog pores, reducing effective air passages and forming closed-cell structures, thus reducing air permeability. Excessively high powder quality significantly increases the viscosity of the mixed solution, leading to poor fluidity of the spinning solution and making it difficult to form uniform and stable fibers.

[0136] Examples 13-14 and Comparative Examples 17-18

[0137] The difference between Examples 13-14 and Comparative Examples 17-18 and Example 1 is that the winding speed of stretching in step S4 is different, as shown in Table 6. The rest is the same as Example 1 and will not be repeated here.

[0138] The ionizing radiation shielding properties, breaking strength, and air permeability of the anti-ionizing radiation fibers prepared in Examples 13-14 and Comparative Examples 17-18 were tested. The test results are shown in Table 6. No test results were obtained for Comparative Example 18 because the drawing speed was too high, making it impossible to prepare fibers.

[0139] Table 6. Performance of the anti-ionizing radiation fibers prepared in Examples 13-14 and Comparative Examples 17-18

[0140]

[0141] As shown in Table 6, the tensile strength of the fiber and the air permeability of the fabric change significantly with varying drawing speeds. This is because at slower drawing speeds, the tensile stress on the fiber is lower, the molecular chain orientation is lower, and the arrangement is loose, failing to form an effective axial stress transfer network. Simultaneously, the rare earth composite powder is easily disordered in the matrix due to insufficient drawing, failing to collaboratively share stress, resulting in lower fiber tensile strength. However, because the molecular chains still retain many disordered regions, the chain segments can achieve greater deformation through slippage and extension during stretching, resulting in higher elongation at break. Secondly, slower drawing speeds lead to increased fiber diameter, a looser fiber structure, and the micropores formed during solidification are not effectively compressed and have good connectivity; insufficient molecular chain orientation results in more retained micropores, leading to higher air permeability.

[0142] As the drafting speed increases, the tensile stress on the fiber increases, causing the molecular chains to highly oriented along the fiber axis, increasing crystallinity and significantly enhancing fiber strength. Simultaneously, while the molecular chains are orderly oriented, they are not excessively stretched, leaving some space for chain segment movement. At this point, the elongation at break gradually decreases with increasing speed. Accelerated drafting also densifies the fiber structure, uniformly compressing the micropores into a small, closed state, reducing connectivity. Therefore, air permeability decreases with increasing speed.

[0143] However, at higher drawing speeds, the tensile stress on the fiber increases, and the molecular chains are forcibly stretched beyond their elastic limits, making them prone to localized breakage or slippage, forming microcracks. Simultaneously, rare earth powder may be squeezed to the fiber surface or accumulate at defects due to intense drawing, becoming stress concentration points, and the breaking strength decreases significantly with increasing speed. Secondly, excessive molecular chain orientation increases rigidity, almost completely suppressing chain segment slippage; at the same time, the presence of microcracks causes brittle fracture of the fiber even with small deformations. In this case, the elongation at break decreases sharply with increasing speed.

[0144] At the same time, a faster drawing speed leads to a reduction in the pore size between fibers, an increase in the tortuosity of the path, and a decrease in air permeability. If the drawing speed is too high and exceeds the fiber's tolerance limit, it may also cause fiber breakage or internal defects, making it impossible to form a complete fiber.

[0145] Examples 15-16 and Comparative Examples 19-20

[0146] The difference between Examples 15-16 and Comparative Examples 19-20 and Example 1 is that the water washing time in step S4 is different, as shown in Table 7. The rest is the same as Example 1 and will not be repeated here.

[0147] The ionizing radiation protection performance, breaking strength, and air permeability of the anti-ionizing radiation fibers prepared in Examples 15-16 and Comparative Examples 19-20 were tested. The test results are shown in Table 7.

[0148] Table 7 Performance of the anti-ionizing radiation fibers in Examples 15-16 and Comparative Examples 19-20

[0149]

[0150] As shown in Table 7, washing time has a significant impact on the mechanical properties and air permeability of the fibers. This is because when the washing time is insufficient, the amount of residual solvent in the fibers is high. During the subsequent drying process, the residual solvent will plasticize the polyurethane matrix, making the molecular chains prone to slippage and interface separation during stretching, resulting in reduced fiber strength. Secondly, the residual solvent will reduce the rigidity of the polyurethane matrix, resulting in a large space for molecular chain sliding, allowing for significant deformation during stretching, leading to a significantly higher elongation at break. Simultaneously, it will fill the micropores inside the fibers, forming a liquid blockage layer, which in turn makes it difficult for gas to pass through the micropores, resulting in low air permeability.

[0151] With appropriate washing time, residual solvents are fully removed, the polyurethane matrix regains its rigidity, and the molecular chains are tightly bonded. At this time, the fiber has the strongest resistance to breakage, the breaking strength reaches its peak, the deformation capacity tends to stabilize, the breaking elongation decreases slightly, the micropores inside the fiber also become unobstructed, and there is no structural deformation caused by swelling. The micropore connectivity is optimal, and the air permeability gradually increases.

[0152] When the washing time is too long, the fibers will absorb too much water and swell, causing the polyurethane matrix to swell. This leads to the loosening of the fiber structure and the shedding of rare earth particles, affecting the radiation resistance performance. At the same time, the swelling of the matrix will also destroy the bond between the hydroxyl groups on the surface of the rare earth powder and the polyurethane molecular chains, forming micro-gaps at the interface, which will reduce the fiber strength and elongation at break. In addition, after excessive washing, the swelling of the polyurethane matrix will squeeze the internal micropores, causing the micropore size to shrink, the connectivity to decrease, and the air permeability to gradually decrease.

[0153] Comparative Example 21

[0154] The difference between Comparative Example 21 and Example 1 is that the rare earth composite powder in step S1 has a non-spherical morphology. That is, the sol prepared in step S1 is only dried and calcined, but not ground. The rest is the same as in Example 1, and will not be repeated here.

[0155] Comparative Example 22

[0156] The difference between Comparative Example 22 and Example 1 lies in the use of dry spinning in step S3. Specifically, the spinning solution obtained in step S3 is stably delivered to the spinneret via a precision gear pump, extruded, and solidified in hot air stretching. Finally, it undergoes heat setting and water washing to obtain anti-ionizing radiation fibers. The specific parameters are: spinning solution flow rate of 5 mL / min, pressure of 0.5 MPa, spinneret diameter of 0.5 mm, number of orifices of 10, spinning length of 8 m, hot air temperature of 180 ℃, air velocity of 1 m / s, winding speed of 200 m / min, and tension of 0.1 cN / dtex. In the post-treatment process, the heat setting temperature is 120 ℃ for 30 min, and the tension is 0.2 cN / dtex. The water washing temperature is 60 ℃ for 30 min. Other parameters are the same as in Example 1 and will not be repeated here.

[0157] The ionizing radiation protection performance, breaking strength, and air permeability of the anti-ionizing radiation fibers prepared in Comparative Examples 21-22 were tested. The test results are shown in Table 8.

[0158] Table 8 Performance of Anti-ionizing Radiation Fibers in Comparative Examples 21-22

[0159]

[0160] As shown in Table 8, when using rare earth composite powders with non-spherical morphology, both the shielding efficiency and tensile strength of the fibers decrease. This is because, in terms of shielding efficiency, the regular spherical structure can reduce the agglomeration effect between powder particles, allowing them to be more uniformly dispersed in the polyurethane matrix, forming a highly efficient radiation shielding network, and significantly improving the shielding efficiency of the fibers against ionizing radiation.

[0161] In terms of fracture strength, the absence of sharp edges in spherical particles reduces their physical cutting effect on the matrix molecular chains, decreasing stress concentration points. Simultaneously, spherical particles can enhance the bonding force between the powder and polyurethane by optimizing interfacial compatibility, achieving uniform load transfer during tensile testing and avoiding strength reduction caused by uneven filler dispersion, thus improving fracture strength. Furthermore, uniformly dispersed spherical particles offer minimal resistance to the sliding of polyurethane molecular chains, allowing them to glide smoothly along the spherical surface, resulting in high elongation at break.

[0162] The shielding efficiency of anti-ionizing radiation fibers prepared by dry spinning and wet spinning is roughly the same. However, in the dry spinning process, the solvent slowly evaporates from the surface of the spinning stream in hot air, allowing the molecular chains sufficient time to align orderly along the stretching direction, resulting in high orientation. Furthermore, without the rapid diffusion interference of a coagulation bath, the fiber structure is denser, with no obvious core-sheath layer or internal voids. Simultaneously, slow coagulation facilitates the uniform dispersion of rare earth powders, resulting in a tighter bond with the matrix interface and higher tensile strength. However, this also further restricts molecular chain movement, making it difficult for the molecular chains to achieve significant deformation through slippage or extension, thus leading to lower elongation at break. Solvent evaporation, on the other hand, creates small, uniform closed or semi-closed micropores, resulting in a denser circular or dumbbell-shaped fiber cross-section, which reduces the fiber's air permeability. In addition, dry spinning requires rapid solvent evaporation via high-temperature hot airflow, consuming significantly more energy than wet spinning, leading to higher production costs.

[0163] The anti-ionizing radiation fiber prepared in Example 1 and the anti-ionizing radiation fiber prepared in Comparative Example 21 were used to prepare anti-ionizing radiation textiles. The anti-ionizing radiation performance was tested after 1 month, 2 months, 3 months, 4 months and 5 months of use, respectively. The durability of their anti-radiation performance was tested, and the test results are shown in Table 9.

[0164] Table 9. Durability Tests of Ionizing Radiation Fibers in Example 1 and Comparative Example 21

[0165]

[0166] As shown in Table 9, under the same usage time, the X-ray shielding efficiency and γ-ray shielding efficiency of the anti-ionizing radiation fiber prepared in Example 1 are higher than those of the anti-ionizing radiation fiber prepared in Comparative Example 21. Moreover, as the usage time increases, the shielding efficiency of the anti-ionizing radiation fiber prepared in Example 1 decreases less, indicating that it has better durability and can maintain better anti-ionizing radiation performance for a longer period of time.

[0167] In summary, this application provides a high-filling-content, high-strength, and high-elasticity anti-ionizing radiation fiber, its preparation method, and its application. First, rare earth composite powder is prepared via a sol-gel method. Then, a spinning solution is prepared using polyurethane as the substrate and the rare earth composite powder as the filler. Nascent fibers are then prepared via wet spinning. Finally, the anti-ionizing radiation fiber is obtained through a series of post-treatments including drawing, washing, and drying. Specifically, by combining multiple rare earth metals, preparing spherical rare earth composite powder through the synergistic effect of grinding and calcination, using a mixed solution of N,N-dimethylformamide and xylene as the spinning solvent, and controlling parameters such as the ratio of raw materials, preparation temperature, time, and stirring speed, an anti-ionizing radiation fiber with high efficiency, broad-spectrum shielding, stable structure, and adjustable function is obtained.

[0168] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A method for preparing a high-filling-weight, high-strength, and highly elastic anti-ionizing radiation fiber, characterized in that, Includes the following steps: S1, firstly, rare earth nitrates and citric acid are dissolved in an acidic alcoholic aqueous solution and heated and stirred to adjust the pH value to obtain a sol. Then, the sol is subjected to a second heating treatment to obtain a gel. Next, the gel is aged, dried, ground, and calcined to obtain rare earth composite powder. The rare earth nitrates are a mixture of gadolinium nitrate, dysprosium nitrate, and cerium nitrate. The mass ratio of gadolinium nitrate to dysprosium nitrate and cerium nitrate is (5-9):2:

1. S2, add polyurethane to a mixed solution of N,N-dimethylformamide and xylene, stir for the first time, and after it is fully dissolved, add the rare earth composite powder obtained in step S1, stir for the second time, and then degas to obtain a spinning solution; the mass ratio of the rare earth composite powder to the polyurethane is (3-9):

1. S3, the spinning solution obtained in step S2 is injected into a metering pump. The spinning solution is squeezed by the metering pump and sprayed out from the spinneret to enter the coagulation bath to form nascent fibers. S4. Stretch, wash and dry the nascent fibers obtained in step S3 to obtain anti-ionizing radiation fibers.

2. The method for preparing high-filling-weight, high-strength, and high-elasticity anti-ionizing radiation fiber according to claim 1, characterized in that, In step S1, the rare earth composite powder is spherical particles with an average particle size in the range of 60-600 nm.

3. The method for preparing high-filling-weight, high-strength, and high-elasticity anti-ionizing radiation fiber according to claim 1, characterized in that, In step S1, the preparation of the acidic alcohol aqueous solution involves mixing alcohol and water, and then adjusting the pH of the solution to 3-5 with nitric acid. In step S1, the mass ratio of alcohol to water in the acidic alcohol aqueous solution is 1:(1-3). In step S1, the mass ratio of citric acid to rare earth nitrate is (0.5-3):

1. In step S1, the mass ratio of the acidic alcohol aqueous solution to rare earth nitrate is (5-15):

1.

4. The method for preparing high-filling-weight, high-strength, and high-elasticity anti-ionizing radiation fiber according to claim 1, characterized in that, In step S1, the heating and stirring time is 1-3 hours, wherein the heating temperature is 40-60℃ and the stirring speed is 300-600 rpm; in step S1, adjusting the pH value refers to adjusting the pH to 6-8 using ammonia water; in step S1, the secondary heating treatment refers to continuously stirring the sol at 80-90℃ until the sol loses its fluidity; in step S1, aging refers to letting the gel stand for 8-12 hours; in step S1, the drying temperature is 100-120℃ and the time is 12-24 hours; in step S1, the grinding refers to wet grinding using ethanol as a medium, wherein the ball-to-material ratio is (8-10):1, the speed is 300-400 rpm, and the time is 18-24 hours; in step S1, the calcination temperature is 500-700℃ and the time is 1-3 hours.

5. The method for preparing high-filling-weight, high-strength, and high-elasticity anti-ionizing radiation fiber according to claim 1, characterized in that, In step S2, the mass ratio of N,N-dimethylformamide to xylene in the mixed solution of N,N-dimethylformamide and xylene is (2-4):1; in step S2, the mass concentration of polyurethane in the mixed solution of N,N-dimethylformamide and xylene is 10-30%.

6. The method for preparing high-filling-weight, high-strength, and high-elasticity anti-ionizing radiation fiber according to claim 1, characterized in that, In step S2, the first stirring time is 1-3 hours and the rotation speed is 300-600 rpm; in step S2, the second stirring time is 2-4 hours and the rotation speed is 200-400 rpm; in step S2, defoaming refers to placing the spinning solution in a vacuum environment and letting it stand for 1-3 hours.

7. The method for preparing high-filling-weight, high-strength, and high-elasticity anti-ionizing radiation fiber according to claim 1, characterized in that, In step S3, the injection flow rate of the metering pump is 0.01-0.1 mL / min; in step S3, the inner diameter of the spinneret is 0.2-1.5 mm; in step S3, the coagulation bath is deionized water or a polar solvent solution, and the coagulation bath temperature is 20-40°C.

8. The method for preparing high-filling-weight, high-strength, and high-elasticity anti-ionizing radiation fiber according to claim 1, characterized in that, In step S4, the winding speed of the stretching is 3-7 m / min; the washing refers to soaking the fiber in a water tank for 1-5 hours; the drying temperature is 50-80°C and the time is 1-3 hours.

9. A method for preparing high-filling-weight, high-strength, and high-elasticity anti-ionizing radiation fiber according to any one of claims 1-8, characterized in that, The high-filling, high-strength, and high-elasticity anti-ionizing radiation fiber has a diameter of 40-500 μm. Under 100 keV conditions, the high-filling, high-strength, and high-elasticity anti-ionizing radiation fiber achieves an X-ray shielding rate of 80.73% and a γ-ray shielding rate of 66.74% under 660 keV conditions. The fiber breaking strength reaches 34.84 MPa, the breaking elongation reaches 307.36%, and the air permeability reaches 401.83 mm / s.

10. The application of the high-filling-weight, high-strength, high-elasticity anti-ionizing radiation fiber prepared by the method of any one of claims 1-8, or the high-filling-weight, high-strength, high-elasticity anti-ionizing radiation fiber of claim 9, characterized in that... The high-filling, high-strength, and high-elasticity anti-ionizing radiation fibers are used to prepare anti-ionizing radiation textiles for the medical protection field.

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