A layered composite radiation-shielding fabric and its preparation method

Abstract

This invention provides a layered composite radiation-shielding fabric, comprising a fabric layer and a radiation-shielding layer. The radiation-shielding layer includes a magnetic bottom layer connected to the fabric layer, a foam intermediate layer, and a nano-carbon particle top layer. In this invention, multiple radiation-shielding layers are laminated onto the surface of the fabric layer. These layers consist of a magnetic bottom layer, a foam intermediate layer, and a nano-carbon particle top layer. The high level of protection is achieved through the combination of different layer structures and radiation-shielding materials.

Description

Technical Field

[0001] This invention relates to the field of functional fabrics, specifically to a layered composite radiation-proof fabric and its preparation method. Background Technology

[0002] Radiation protection materials have been used for many years. Traditional protective materials generally use lead and lead oxides as shielding materials, or metal plates, such as iron plates. Although these materials can provide protection to a certain extent, with rapid economic development, their bulky and thick nature makes them difficult to meet people's requirements. Currently, the most researched approach is to use polymers as a matrix, adding protective solid granules, and then using processes such as polymer composites to prepare new types of protective materials.

[0003] This type of fiber is made by spinning fibers using polymer materials as the matrix and adding various conductive substances (such as carbon black, graphite, metal powder, and metal oxides). However, the development of this type of fiber presents challenges. To achieve good electromagnetic radiation shielding performance, it is necessary to increase the amount of inorganic conductive and magnetic substances added, which reduces the fiber's spinnability and may even prevent it from forming into fibers. Therefore, there is an urgent need to find a lightweight radiation-shielding fabric that combines both light weight and high protective performance. Summary of the Invention

[0004] The technical problem to be solved: The purpose of this invention is to provide a layered composite radiation protection fabric, which is a lightweight and highly protective radiation protection fabric obtained by compositely bonding a layered radiation protection layer to the outside of the fabric layer.

[0005] Technical solution: A layered composite radiation protection fabric, the radiation protection fabric comprising a fabric layer and a radiation protection layer, the radiation protection layer comprising a magnetic bottom layer connected to the fabric layer, a foam intermediate layer and a nano-carbon ball particle top layer.

[0006] The preparation method of the above-mentioned layered composite radiation-proof fabric includes the following steps:

[0007] S1. Preparation of the upper layer of nano-carbon spheres: Glucose is added to water to prepare a glucose aqueous solution. The glucose solution is subjected to hydrothermal reaction in a reaction vessel to obtain closed-pore nano-carbon spheres.

[0008] S2. Preparation of mixed aqueous polyurethane solution: Closed-pore carbon nanospheres, Ni-doped Fe3O4 nanoparticles and rare earth-doped carbonized discrete fiber mesh are added to aqueous polyurethane solution and ultrasonically stirred to obtain mixed aqueous polyurethane solution.

[0009] S3. Preparation of the radiation shielding layer: Pour the mixed aqueous polyurethane solution prepared in step S2 into the mold and spread it evenly. Let it stand until the Ni-doped Fe3O4 nanoparticles sink to the bottom of the mold and the closed-pore carbon nanospheres float on the surface of the mold. Then, freeze the mold in liquid nitrogen and then freeze-dry it to obtain the radiation shielding layer.

[0010] S4. Preparation of anti-radiation fabric: One side of the magnetic bottom layer is coated with adhesive, and then it is laminated with the fabric layer to obtain a layered composite anti-radiation fabric.

[0011] Preferably, in step S1, the concentration of the glucose aqueous solution is 10-15 wt%, the hydrothermal reaction temperature is 180-200℃, and the time is 3-5 h.

[0012] Preferably, in step S2, the concentration of the waterborne polyurethane is 25-33 wt%, the mass ratio of the closed-cell carbon nanospheres, Ni-doped Fe3O4 nanoparticles and rare earth-doped carbonized discrete fiber network is 1:10-15:3-5, and the content of the rare earth-doped carbonized discrete fiber network in the waterborne polyurethane is 2-4 wt%.

[0013] Preferably, the preparation method of the Ni-doped Fe3O4 nanoparticles is as follows: ferric chloride and nickel chloride are added to an ethanol solution and stirred to dissolve them. Then, trisodium citrate and sodium acetate are added, stirred to dissolve them, and reacted at 160-190℃ for 10-20h to obtain Ni-doped Fe3O4 nanoparticles.

[0014] Preferably, the rare earth-doped carbonized discrete fiber web is prepared by the following steps:

[0015] S11. Add cotton fibers and rare earth chlorides to a LiCl-containing N,N-dimethylacetamide solution, stir and dissolve evenly to obtain a rare earth-doped cotton fiber solution with a concentration of 6-10 wt%.

[0016] S12. Rare earth-doped cotton fiber solution is electrospun in a multi-needle water bath with 4-5 needles arranged in a row to obtain electrospun regenerated cellulose fiber bundles.

[0017] S13. The electrospun regenerated cellulose fiber bundles are cut to 0.5-1cm and then subjected to steam explosion to disperse the cotton fiber bundle nanofibers. The dispersed nanofibers are then carbonized at a temperature of 400-450℃ for 20-30 minutes to obtain a rare earth-doped carbonized discrete fiber network.

[0018] Preferably, in step S11, the rare earth chloride is any one of LaCl3, CeCl3 or SmCl3, and the mass ratio of rare earth chloride to cotton fiber is 1:20-30.

[0019] Preferably, in step S12, the electrospinning voltage is 25-30kV, the needle spacing is 3cm, and the spinning solution flow rate per needle is 0.15mL / h.

[0020] Preferably, in step S13, the steam explosion pressure is 0.5-0.8 MPa and the pressure holding time is 30-50 s.

[0021] Preferably, in step S3, the liquid nitrogen freezing time is 10-20 min, the freeze-drying temperature is -60 to -40℃, and the freeze-drying time is 20-40 h.

[0022] Beneficial effects: The layered composite radiation-proof fabric of the present invention has the following advantages:

[0023] 1. In this invention, multiple radiation-shielding layers are laminated onto the surface of the fabric layer. The radiation-shielding layers consist of a magnetic bottom layer, a foam middle layer, and a nano-carbon ball particle top layer. The high protection effect is achieved through the combination of different layer structures and radiation-shielding materials.

[0024] 2. The main material of the radiation shielding layer in this invention is a polyurethane foam intermediate layer containing carbon fibers. Polyurethane foam itself does not have the effect of radiation shielding. Rare earth doped carbonized discrete fiber network is added to polyurethane. The radiation reflection effect of the polyurethane foam intermediate layer is improved by the action of carbonized fibers and rare earth ions.

[0025] 3. In this invention, the closed-cell carbon nanospheres are lightweight and can be suspended in the upper layer of the polyurethane solution, while the Ni-doped Fe3O4 nanoparticles are dense enough to sink to the bottom layer. After being flash-frozen with liquid nitrogen, the closed-cell carbon nanospheres and Ni-doped Fe3O4 nanoparticles can be fixed in place. During radiation, the radiation first passes through the closed-cell carbon nanospheres, where some of the radiation can be reflected or absorbed. Then it passes through the foam intermediate layer, which also reflects some of the radiation due to its numerous pores. Finally, it passes through the magnetic bottom layer, where it can also be reflected. Ultimately, the layered structure achieves a good shielding effect. Detailed Implementation

[0026] The present invention will be further described below with reference to embodiments. These embodiments are illustrative of the present invention, but the present invention is not limited to these embodiments:

[0027] Example 1

[0028] Rare earth-doped carbonized discrete fiber mesh is prepared through the following steps:

[0029] S11. Add cotton fibers and LaCl3 to a LiCl-containing N,N-dimethylacetamide solution, with a mass ratio of LaCl3 to cotton fibers of 1:20. Stir and dissolve evenly to obtain a rare earth-doped cotton fiber solution with a concentration of 6 wt%.

[0030] S12. Rare earth-doped cotton fiber solution is electrospun using a multi-needle water bath with 4 needles arranged in a row. The electrospinning voltage is 25kV, the needle spacing is 3cm, and the flow rate of the spinning solution per needle is 0.15mL / h to obtain electrospun regenerated cellulose fiber bundles.

[0031] S13. The electrospun regenerated cellulose fiber bundles were cut to 0.5-1cm and subjected to steam explosion at a pressure of 0.5MPa for 50s to disperse the cotton fiber bundle nanofibers. The dispersed nanofibers were then carbonized at a temperature of 400℃ for 20min to obtain a rare earth-doped carbonized discrete fiber network.

[0032] Example 2

[0033] Rare earth-doped carbonized discrete fiber mesh is prepared through the following steps:

[0034] S11. Add cotton fibers and LaCl3 to a LiCl-containing N,N-dimethylacetamide solution, with a mass ratio of LaCl3 to cotton fibers of 1:30. Stir and dissolve evenly to obtain a rare earth-doped cotton fiber solution with a concentration of 10 wt%.

[0035] S12. Rare earth-doped cotton fiber solution is electrospun using a multi-needle water bath with 5 needles arranged in a row. The electrospinning voltage is 30kV, the needle spacing is 3cm, and the flow rate of the spinning solution per needle is 0.15mL / h to obtain electrospun regenerated cellulose fiber bundles.

[0036] S13. The electrospun regenerated cellulose fiber bundles were cut to 0.5-1cm and subjected to steam explosion at a pressure of 0.8MPa for 30s to disperse the cotton fiber bundle nanofibers. The dispersed nanofibers were then carbonized at a temperature of 450℃ for 30min to obtain a rare earth-doped carbonized discrete fiber network.

[0037] Example 3

[0038] A method for preparing a layered composite radiation-shielding fabric, the method comprising the following steps:

[0039] S1. Preparation of the upper layer of nano-carbon spheres: Glucose was added to water to prepare a 10wt% glucose aqueous solution. The glucose solution was subjected to a hydrothermal reaction in a reactor at a temperature of 180℃ for 5 hours to obtain closed-cell nano-carbon spheres. S2. Preparation of mixed aqueous polyurethane solution: Closed-cell nano-carbon spheres, Ni-doped Fe3O4 nanoparticles, and the rare earth-doped carbonized discrete fiber network prepared in Example 1 were added to an aqueous polyurethane solution with a concentration of 25wt%. The mass ratio of closed-cell nano-carbon spheres, Ni-doped Fe3O4 nanoparticles, and rare earth-doped carbonized discrete fiber network was 1:10:3. The content of rare earth-doped carbonized discrete fiber network in the aqueous polyurethane was 2wt%. The mixture was ultrasonically stirred to obtain a mixed aqueous polyurethane solution.

[0040] S3. Preparation of the radiation shielding layer: The mixed aqueous polyurethane solution prepared in step S2 is poured into the mold and spread evenly. It is allowed to stand until the Ni-doped Fe3O4 nanoparticles settle to the bottom of the mold and the closed-pore carbon nanospheres float on the surface of the mold. Then the mold is first frozen in liquid nitrogen for 10 min and then freeze-dried at a temperature of -40℃ for 40 h to obtain a radiation shielding layer with a thickness of 1.4 mm.

[0041] S4. Preparation of anti-radiation fabric: Coat one side of the magnetic bottom layer with adhesive, and then combine it with the fabric layer to obtain a layered composite anti-radiation fabric.

[0042] The method for preparing Ni-doped Fe3O4 nanoparticles is as follows: ferric chloride and nickel chloride are added to an ethanol solution and stirred until dissolved. Then, trisodium citrate and sodium acetate are added. The molar ratio of ferric chloride, nickel chloride, trisodium citrate, and sodium acetate is 1:0.2:3:2.2. After stirring and dissolving, the mixture is reacted at 160°C for 20 hours to obtain Ni-doped Fe3O4 nanoparticles.

[0043] Example 4

[0044] A method for preparing a layered composite radiation-shielding fabric, the method comprising the following steps:

[0045] S1. Preparation of the upper layer of nano-carbon spheres: Glucose was added to water to prepare a 15wt% glucose aqueous solution. The glucose solution was subjected to a hydrothermal reaction in a reactor at a temperature of 200℃ for 3 hours to obtain closed-cell nano-carbon spheres. S2. Preparation of mixed aqueous polyurethane solution: Closed-cell nano-carbon spheres, Ni-doped Fe3O4 nanoparticles, and the rare earth-doped carbonized discrete fiber network prepared in Example 1 were added to an aqueous polyurethane solution with a concentration of 33wt%. The mass ratio of closed-cell nano-carbon spheres, Ni-doped Fe3O4 nanoparticles, and rare earth-doped carbonized discrete fiber network was 1:15:5. The content of rare earth-doped carbonized discrete fiber network in the aqueous polyurethane was 4wt%. The mixture was ultrasonically stirred to obtain a mixed aqueous polyurethane solution.

[0046] S3. Preparation of the radiation shielding layer: The mixed aqueous polyurethane solution prepared in step S2 is poured into the mold and spread evenly. It is allowed to stand until the Ni-doped Fe3O4 nanoparticles settle to the bottom of the mold and the closed-pore carbon nanospheres float on the surface of the mold. Then the mold is first frozen in liquid nitrogen for 20 minutes and then freeze-dried at a temperature of -60℃ for 20 hours to obtain a radiation shielding layer with a thickness of 1.5 mm.

[0047] S4. Preparation of anti-radiation fabric: Coat one side of the magnetic bottom layer with adhesive, and then combine it with the fabric layer to obtain a layered composite anti-radiation fabric.

[0048] The method for preparing Ni-doped Fe3O4 nanoparticles is as follows: ferric chloride and nickel chloride are added to an ethanol solution and stirred until dissolved. Then, trisodium citrate and sodium acetate are added. The molar ratio of ferric chloride, nickel chloride, trisodium citrate, and sodium acetate is 1:0.2:3:2.2. After stirring and dissolving, the mixture is reacted at 190°C for 10 hours to obtain Ni-doped Fe3O4 nanoparticles.

[0049] Example 5

[0050] A method for preparing a layered composite radiation-shielding fabric, the method comprising the following steps:

[0051] S1. Preparation of the upper layer of nano-carbon spheres: Glucose was added to water to prepare an 11.5 wt% glucose aqueous solution. The glucose solution was subjected to a hydrothermal reaction in a reactor at a temperature of 185°C for 5 hours to obtain closed-cell nano-carbon spheres. S2. Preparation of mixed aqueous polyurethane solution: Closed-cell nano-carbon spheres, Ni-doped Fe3O4 nanoparticles, and the rare earth-doped carbonized discrete fiber network prepared in Example 2 were added to an aqueous polyurethane solution with a concentration of 28 wt%. The mass ratio of closed-cell nano-carbon spheres, Ni-doped Fe3O4 nanoparticles, and rare earth-doped carbonized discrete fiber network was 1:12:4. The content of rare earth-doped carbonized discrete fiber network in the aqueous polyurethane was 4 wt%. The mixture was ultrasonically stirred to obtain a mixed aqueous polyurethane solution.

[0052] S3. Preparation of the radiation shielding layer: The mixed aqueous polyurethane solution prepared in step S2 is poured into the mold and spread evenly. It is allowed to stand until the Ni-doped Fe3O4 nanoparticles settle to the bottom of the mold and the closed-pore carbon nanospheres float on the surface of the mold. Then the mold is first frozen in liquid nitrogen for 12 minutes and then freeze-dried at a temperature of -50℃ for 35 hours to obtain a radiation shielding layer with a thickness of 1.3 mm.

[0053] S4. Preparation of anti-radiation fabric: Coat one side of the magnetic bottom layer with adhesive, and then combine it with the fabric layer to obtain a layered composite anti-radiation fabric.

[0054] The method for preparing Ni-doped Fe3O4 nanoparticles is as follows: ferric chloride and nickel chloride are added to an ethanol solution and stirred until dissolved. Then, trisodium citrate and sodium acetate are added. The molar ratio of ferric chloride, nickel chloride, trisodium citrate, and sodium acetate is 1:0.2:3:2.2. After stirring and dissolving, the mixture is reacted at 180°C for 10 hours to obtain Ni-doped Fe3O4 nanoparticles.

[0055] Example 6

[0056] A method for preparing a layered composite radiation-shielding fabric, the method comprising the following steps:

[0057] S1. Preparation of the upper layer of nano-carbon spheres: Glucose was added to water to prepare a 14wt% glucose aqueous solution. The glucose solution was subjected to a hydrothermal reaction in a reactor at a temperature of 195℃ for 4 hours to obtain closed-cell nano-carbon spheres. S2. Preparation of mixed aqueous polyurethane solution: Closed-cell nano-carbon spheres, Ni-doped Fe3O4 nanoparticles, and the rare earth-doped carbonized discrete fiber network prepared in Example 2 were added to an aqueous polyurethane solution with a concentration of 32wt%. The mass ratio of closed-cell nano-carbon spheres, Ni-doped Fe3O4 nanoparticles, and rare earth-doped carbonized discrete fiber network was 1:14:5. The content of rare earth-doped carbonized discrete fiber network in the aqueous polyurethane was 3wt%. The mixture was ultrasonically stirred to obtain a mixed aqueous polyurethane solution.

[0058] S3. Preparation of the radiation shielding layer: The mixed aqueous polyurethane solution prepared in step S2 is poured into the mold and spread evenly. It is allowed to stand until the Ni-doped Fe3O4 nanoparticles settle to the bottom of the mold and the closed-pore carbon nanospheres float on the surface of the mold. Then the mold is first frozen in liquid nitrogen for 18 minutes and then freeze-dried at a temperature of -40℃ for 35 hours to obtain a radiation shielding layer with a thickness of 1.4 mm.

[0059] S4. Preparation of anti-radiation fabric: Coat one side of the magnetic bottom layer with adhesive, and then combine it with the fabric layer to obtain a layered composite anti-radiation fabric.

[0060] The method for preparing Ni-doped Fe3O4 nanoparticles is as follows: ferric chloride and nickel chloride are added to an ethanol solution and stirred until dissolved. Then, trisodium citrate and sodium acetate are added. The molar ratio of ferric chloride, nickel chloride, trisodium citrate, and sodium acetate is 1:0.2:3:2.2. After stirring and dissolving, the mixture is reacted at 190°C for 10 hours to obtain Ni-doped Fe3O4 nanoparticles.

[0061] Example 7

[0062] A method for preparing a layered composite radiation-shielding fabric, the method comprising the following steps:

[0063] S1. Preparation of the upper layer of nano-carbon spheres: Glucose was added to water to prepare a 13wt% glucose aqueous solution. The glucose solution was subjected to a hydrothermal reaction in a reaction vessel at a temperature of 190℃ for 4.5h to obtain closed-pore nano-carbon spheres.

[0064] S2. Preparation of mixed aqueous polyurethane solution: Closed-pore carbon nanospheres, Ni-doped Fe3O4 nanoparticles and rare earth-doped carbonized discrete fiber mesh prepared in Example 1 were added to an aqueous polyurethane solution with a concentration of 30 wt%. The mass ratio of closed-pore carbon nanospheres, Ni-doped Fe3O4 nanoparticles and rare earth-doped carbonized discrete fiber mesh was 1:13:4.5, and the content of rare earth-doped carbonized discrete fiber mesh in the aqueous polyurethane was 3.5 wt%. The mixture was ultrasonically stirred to obtain a mixed aqueous polyurethane solution.

[0065] S3. Preparation of the radiation shielding layer: The mixed aqueous polyurethane solution prepared in step S2 is poured into the mold and spread evenly. It is allowed to stand until the Ni-doped Fe3O4 nanoparticles settle to the bottom of the mold and the closed-pore carbon nanospheres float on the surface of the mold. Then the mold is first frozen in liquid nitrogen for 15 minutes and then freeze-dried at a temperature of -45℃ for 30 hours to obtain a radiation shielding layer with a thickness of 1.3 mm.

[0066] S4. Preparation of anti-radiation fabric: Coat one side of the magnetic bottom layer with adhesive, and then combine it with the fabric layer to obtain a layered composite anti-radiation fabric.

[0067] The method for preparing Ni-doped Fe3O4 nanoparticles is as follows: ferric chloride and nickel chloride are added to an ethanol solution and stirred until dissolved. Then, trisodium citrate and sodium acetate are added. The molar ratio of ferric chloride, nickel chloride, trisodium citrate, and sodium acetate is 1:0.2:3:2.2. After stirring and dissolving, the mixture is reacted at 180°C for 16 hours to obtain Ni-doped Fe3O4 nanoparticles.

[0068] Comparative Example 1

[0069] A method for preparing a layered composite radiation-shielding fabric, the method comprising the following steps:

[0070] S1. Preparation of the upper layer of nano-carbon spheres: Glucose was added to water to prepare a 15wt% glucose aqueous solution. The glucose solution was subjected to a hydrothermal reaction in a reactor at a temperature of 195℃ for 4 hours to obtain closed-cell nano-carbon spheres. S2. Preparation of mixed aqueous polyurethane solution: Closed-cell nano-carbon spheres, Fe3O4 nanoparticles, and the rare earth-doped carbonized discrete fiber network prepared in Example 2 were added to an aqueous polyurethane solution with a concentration of 32wt%. The mass ratio of closed-cell nano-carbon spheres, Fe3O4 nanoparticles, and rare earth-doped carbonized discrete fiber network was 1:14:4. The content of rare earth-doped carbonized discrete fiber network in the aqueous polyurethane was 3.2wt%. The mixture was ultrasonically stirred to obtain a mixed aqueous polyurethane solution.

[0071] S3. Preparation of the radiation shielding layer: The mixed aqueous polyurethane solution prepared in step S2 is poured into the mold and spread evenly. It is allowed to stand until the Ni-doped Fe3O4 nanoparticles settle to the bottom of the mold and the closed-pore carbon nanospheres float on the surface of the mold. Then the mold is first frozen in liquid nitrogen for 18 minutes and then freeze-dried at a temperature of -40℃ for 35 hours to obtain a radiation shielding layer with a thickness of 1.4 mm.

[0072] S4. Preparation of anti-radiation fabric: One side of the magnetic bottom layer is coated with adhesive, and then it is laminated with the fabric layer to obtain a layered composite anti-radiation fabric.

[0073] Comparative Example 2

[0074] A method for preparing a layered composite radiation-shielding fabric, the method comprising the following steps:

[0075] S1. Preparation of mixed aqueous polyurethane solution: Ni-doped Fe3O4 nanoparticles and rare earth-doped carbonized discrete fiber mesh prepared in Example 1 were added to an aqueous polyurethane solution with a concentration of 30 wt%. The mass ratio of Ni-doped Fe3O4 nanoparticles to rare earth-doped carbonized discrete fiber mesh was 10:4.5, and the content of rare earth-doped carbonized discrete fiber mesh in the aqueous polyurethane was 3.4 wt%. The solution was ultrasonically stirred to obtain a mixed aqueous polyurethane solution.

[0076] S2. Preparation of the radiation shielding layer: The mixed aqueous polyurethane solution prepared in step S1 is poured into a mold and spread out. It is allowed to stand until the Ni-doped Fe3O4 nanoparticles settle to the bottom of the mold. Then the mold is first frozen in liquid nitrogen for 15 minutes, and then freeze-dried at -50℃ for 30 hours to obtain a radiation shielding layer with a thickness of 1.3 mm.

[0077] S3. Preparation of anti-radiation fabric: Coat one side of the magnetic bottom layer with adhesive, and then combine it with the fabric layer to obtain a layered composite anti-radiation fabric.

[0078] The method for preparing Ni-doped Fe3O4 nanoparticles is as follows: ferric chloride and nickel chloride are added to an ethanol solution and stirred until dissolved. Then, trisodium citrate and sodium acetate are added. The molar ratio of ferric chloride, nickel chloride, trisodium citrate, and sodium acetate is 1:0.2:3:2.2. After stirring and dissolving, the mixture is reacted at 180°C for 18 hours to obtain Ni-doped Fe3O4 nanoparticles.

[0079] Comparative Example 3

[0080] A method for preparing a layered composite radiation-shielding fabric, the method comprising the following steps:

[0081] S1. Preparation of the upper layer of nano-carbon spheres: Glucose was added to water to prepare an 11.5 wt% glucose aqueous solution. The glucose solution was subjected to a hydrothermal reaction in a reactor at a temperature of 185°C for 5 hours to obtain closed-cell nano-carbon spheres. S2. Preparation of mixed aqueous polyurethane solution: Closed-cell nano-carbon spheres and rare earth-doped carbonized discrete fiber mesh prepared in Example 2 were added to an aqueous polyurethane solution with a concentration of 28 wt%. The mass ratio of closed-cell nano-carbon spheres to rare earth-doped carbonized discrete fiber mesh was 1:3, and the content of rare earth-doped carbonized discrete fiber mesh in the aqueous polyurethane was 4 wt%. The mixture was ultrasonically stirred to obtain a mixed aqueous polyurethane solution.

[0082] S3. Preparation of the radiation shielding layer: The mixed aqueous polyurethane solution prepared in step S2 is poured into the mold and spread evenly. It is allowed to stand until the closed-pore carbon nanospheres float on the surface of the mold. Then the mold is first frozen in liquid nitrogen for 12 minutes, and then freeze-dried at -50℃ for 35 hours to obtain a radiation shielding layer with a thickness of 1.3 mm.

[0083] S4. Preparation of anti-radiation fabric: Coat one side of the foam layer with adhesive, and then laminate it with the fabric layer to obtain a layered composite anti-radiation fabric.

[0084] Comparative Example 4

[0085] A method for preparing a layered composite radiation-shielding fabric, the method comprising the following steps:

[0086] S1. Preparation of the upper layer of nano-carbon spheres: Glucose was added to water to prepare a 15wt% glucose aqueous solution. The glucose solution was subjected to a hydrothermal reaction in a reactor at a temperature of 200℃ for 3 hours to obtain closed-cell nano-carbon spheres. S2. Preparation of mixed aqueous polyurethane solution: Closed-cell nano-carbon spheres, Ni-doped Fe3O4 nanoparticles, and the rare earth-doped carbonized discrete fiber network prepared in Example 1 were added to an aqueous polyurethane solution with a concentration of 33wt%. The mass ratio of closed-cell nano-carbon spheres, Ni-doped Fe3O4 nanoparticles, and rare earth-doped carbonized discrete fiber network was 1:15:5. The content of rare earth-doped carbonized discrete fiber network in the aqueous polyurethane was 4wt%. The mixture was ultrasonically stirred to obtain a mixed aqueous polyurethane solution.

[0087] S3. Preparation of the radiation shielding layer: Pour the mixed aqueous polyurethane solution prepared in step S2 into the mold and spread it evenly. Let it stand until the Ni-doped Fe3O4 nanoparticles settle to the bottom of the mold and the closed-pore carbon nanospheres float on the surface of the mold. Then dry to obtain a radiation shielding layer with a thickness of 1.4 mm.

[0088] S4. Preparation of anti-radiation fabric: Coat one side of the magnetic bottom layer with adhesive, and then combine it with the fabric layer to obtain a layered composite anti-radiation fabric.

[0089] The method for preparing Ni-doped Fe3O4 nanoparticles is as follows: ferric chloride and nickel chloride are added to an ethanol solution and stirred until dissolved. Then, trisodium citrate and sodium acetate are added. The molar ratio of ferric chloride, nickel chloride, trisodium citrate, and sodium acetate is 1:0.2:3:2.2. After stirring and dissolving, the mixture is reacted at 190°C for 10 hours to obtain Ni-doped Fe3O4 nanoparticles.

[0090] Comparative Example 5

[0091] A method for preparing a layered composite radiation-shielding fabric, the method comprising the following steps:

[0092] S1. Preparation of the upper layer of nano-carbon spheres: Glucose was added to water to prepare a 10wt% glucose aqueous solution. The glucose solution was subjected to a hydrothermal reaction in a reactor at a temperature of 180℃ for 5 hours to obtain closed-cell nano-carbon spheres. S2. Preparation of mixed aqueous polyurethane solution: Closed-cell nano-carbon spheres, Ni-doped Fe3O4 nanoparticles, and rare earth-doped carbon fiber bundles were added to an aqueous polyurethane solution with a concentration of 25wt%. The mass ratio of closed-cell nano-carbon spheres, Ni-doped Fe3O4 nanoparticles, and rare earth-doped carbon fiber bundles was 1:10:4. The content of rare earth-doped carbon fiber bundles in the aqueous polyurethane was 5wt%. The mixture was ultrasonically stirred to obtain a mixed aqueous polyurethane solution.

[0093] S3. Preparation of the radiation shielding layer: The mixed aqueous polyurethane solution prepared in step S2 is poured into the mold and spread evenly. It is allowed to stand until the Ni-doped Fe3O4 nanoparticles settle to the bottom of the mold and the closed-pore carbon nanospheres float on the surface of the mold. Then the mold is first frozen in liquid nitrogen for 10 min and then freeze-dried at a temperature of -40℃ for 40 h to obtain a radiation shielding layer with a thickness of 1.4 mm.

[0094] S4. Preparation of anti-radiation fabric: Coat one side of the magnetic bottom layer with adhesive, and then combine it with the fabric layer to obtain a layered composite anti-radiation fabric.

[0095] The preparation method of the Ni-doped Fe3O4 nanoparticles is as follows: ferric chloride and nickel chloride are added to an ethanol solution and stirred to dissolve them. Then, trisodium citrate and sodium acetate are added. The molar ratio of ferric chloride, nickel chloride, trisodium citrate and sodium acetate is 1:0.2:3:2.2. After stirring to dissolve, the mixture is reacted at 160℃ for 20h to obtain Ni-doped Fe3O4 nanoparticles.

[0096] Rare earth-doped carbonized fiber bundles are prepared through the following steps:

[0097] S11. Add cotton fibers and LaCl3 to a LiCl-containing N,N-dimethylacetamide solution, with a mass ratio of LaCl3 to cotton fibers of 1:30. Stir and dissolve evenly to obtain a rare earth-doped cotton fiber solution with a concentration of 10 wt%.

[0098] S12. Rare earth-doped cotton fiber solution is electrospun using a multi-needle water bath with 5 needles arranged in a row. The electrospinning voltage is 30kV, the needle spacing is 3cm, and the flow rate of the spinning solution per needle is 0.15mL / h. Electrospun regenerated cellulose fiber bundles are then carbonized at a temperature of 450℃ for 30min to obtain rare earth-doped carbonized fiber bundles.

[0099] Electromagnetic shielding effectiveness test: To test the radiation protection performance of layered composite radiation-proof fabrics, the radiation protection performance of layered composite radiation-proof fabrics was tested according to GB / T23463-2009 "Protective Clothing - Microwave Radiation Protective Clothing". The test frequency range was 10–3000MHz, and the minimum shielding effectiveness at three frequency points (915MHz, 1265MHz, and 2450MHz) was used to evaluate the protective effectiveness of the finished fabric.

[0100]

[0101] Note: In Examples 3-7 and Comparative Examples 1-5, the fabric layer was made of nylon fabric with the same warp and weft density.

[0102] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A layered composite radiation shielding fabric, characterized in that: The radiation-proof fabric comprises a fabric layer and a radiation-proof layer, wherein the radiation-proof layer comprises a magnetic bottom layer connected with the fabric layer, a foamed middle layer and a nano carbon ball particle upper layer. The preparation method of the layered composite radiation-proof fabric comprises the following steps: S1. Preparation of the nano carbon ball particle upper layer: glucose is added to water to prepare a glucose aqueous solution, and the glucose aqueous solution is subjected to hydrothermal reaction in a reaction kettle to obtain closed nano carbon balls; S2. Preparation of a mixed waterborne polyurethane solution: the closed nano carbon balls, Ni-doped Fe3O4 nanoparticles and rare earth-doped carbonized discrete fiber network are added to the waterborne polyurethane solution, and ultrasonic stirring is performed to obtain the mixed waterborne polyurethane solution; S3. Preparation of the radiation-proof layer: the mixed waterborne polyurethane solution prepared in step S2 is poured into a mold and laid flat, and is left to stand until the Ni-doped Fe3O4 nanoparticles settle at the bottom of the mold and the closed nano carbon balls float on the surface of the mold, then the mold is first frozen in liquid nitrogen and then freeze-dried to obtain the radiation-proof layer; S4. Preparation of the radiation-proof fabric: one side of the magnetic bottom layer is coated with an adhesive, and then the fabric layer is compounded to obtain the layered composite radiation-proof fabric; The preparation method of the Ni-doped Fe3O4 nanoparticles is as follows: iron chloride and nickel chloride are added to an ethanol solution, stirred to dissolve, then trisodium citrate and sodium acetate are added, stirred to dissolve, and then reacted at 160-190°C for 10-20h to obtain the Ni-doped Fe3O4 nanoparticles; The rare earth-doped carbonized discrete fiber network is prepared by the following steps: S11. Cotton fibers and rare earth chlorides are added to a LiCl-containing N,N-dimethylacetamide solution, stirred to dissolve uniformly to obtain a rare earth-doped cotton fiber solution with a concentration of 6-10wt%; S12. The rare earth-doped cotton fiber solution is electrospun using a multi-needle water bath, and 4-5 needles are arranged side by side to obtain an electrospun regenerated cellulose fiber bundle; S13. The electrospun regenerated cellulose fiber bundle is cut to 0.5-1cm, steam exploded to disperse the cotton fiber bundle nanofibers, and the dispersed nanofibers are carbonized at a temperature of 400-450°C for 20-30min to obtain the rare earth-doped carbonized discrete fiber network.

2. The layered composite radiation shielding fabric of claim 1, wherein: In step S1, the concentration of the glucose aqueous solution is 10-15wt%, the hydrothermal reaction temperature is 180-200°C, and the time is 3-5h.

3. The layered composite radiation shielding fabric of claim 1, wherein: In step S2, the concentration of the waterborne polyurethane solution is 25-33wt%, the mass ratio of the closed nano carbon balls, Ni-doped Fe3O4 nanoparticles and rare earth-doped carbonized discrete fiber network is 1:10-15:3-5, and the content of the rare earth-doped carbonized discrete fiber network in the waterborne polyurethane solution is 2-4wt%.

4. The layered composite radiation shielding fabric of claim 1, wherein: In step S11, the rare earth chlorides are any one of LaCl3, CeCl3 or SmCl3, and the mass ratio of the rare earth chlorides to the cotton fibers is 1:20-30.

5. The layered composite radiation shielding fabric of claim 1, wherein: The electrostatic spinning voltage in the step S12 is 25-30 kV, the distance between the needles is 3 cm, and the flow rate of the spinning solution of each needle is 0.15 mL / h.

6. The layered composite radiation shielding fabric of claim 1, wherein: The steam explosion pressure in the step S13 is 0.5-0.8 MPa, and the pressure maintaining time is 30-50 s.

7. The layered composite radiation shielding fabric of claim 1, wherein: The liquid nitrogen freezing time in the step S3 is 10-20 min, the freeze-drying temperature is -60 to -40 ℃, and the freeze-drying time is 20-40 h.

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