CN112900155A

CN112900155A - Preparation method of non-woven fabric for X and gamma ray protection

Info

Publication number: CN112900155A
Application number: CN202110170798.4A
Authority: CN
Inventors: 姚理荣; 夏勇; 杨涛; 孙通; 潘刚伟; 徐思峻; 季涛; 高强
Original assignee: Nantong University
Current assignee: Nantong University
Priority date: 2021-02-08
Filing date: 2021-02-08
Publication date: 2021-06-04
Anticipated expiration: 2041-02-08
Also published as: CN112900155B

Abstract

The present application provides a method for preparing a core-shell structure tungsten/gadolinium oxide PP non-woven fabric for X and γ-ray protection. First, a core-shell structure tungsten/gadolinium oxide powder is prepared; W@Gd ₂ O ₃ / PP blend melt; prepare W@Gd ₂ O ₃ /PP composite fiber according to the above blend melt; finally prepare W@Gd ₂ O ₃ /PP composite non-woven material according to the above composite fiber. The core-shell structure tungsten/gadolinium oxide PP non-woven fabric prepared according to the method can play a synergistic protective role in radiation protection, eliminate weak protection areas and effectively absorb secondary radiation generated by radiation. Secondly, the prepared functional non-woven fabric has the characteristics of lead-free and lightweight, and has good application prospects in X and γ-ray radiation protection.

Description

Preparation method of non-woven fabric for X and gamma ray protection

Technical Field

The application relates to the field of radiation protection, in particular to a preparation method of non-woven fabric for X and gamma ray protection.

Background

The development of nuclear technology brings convenience to people and simultaneously generates a lot of radiation hazards, and the light, flexible and excellent-protection-performance textile for radiation protection is a hot spot of current research. The radiation protection material is mainly divided into a lead material and a lead-free material. Lead is mainly lead, and although the protective effect is good, the lead has toxicity, poor strength and large low-energy X-ray scattering. The lead-free material mainly comprises a composite material prepared from rare earth elements and heavy metal compounds such as tin, tungsten, bismuth and the like, and has excellent protection effect, light weight and safety.

In recent years, micro-nano core-shell materials with special structures attract wide attention of people. The composite particles with different core-shell microstructures have unique physicochemical properties, so that the composite particles have wide application prospects in various fields such as optics, electronics, catalysis, biology, radiation and the like. In the aspect of radiation protection, compared with a single metal physical blending mode, the radiation protection material with the core-shell structure can realize synergistic protection, eliminate a protection weak area and effectively absorb secondary radiation generated by radiation. The preparation method of the core-shell structure mainly comprises a template method, a precipitation method, a hydrothermal synthesis method, a spray drying method, a layer-by-layer self-assembly technology and the like. Li et al prepared gadolinium oxide hollow spheres with controllable shell thickness by using silicon dioxide as a template and adopting a homogeneous precipitation method. However, these methods have disadvantages of many steps and long time, so that it is necessary to specify an effective and simple method to overcome these disadvantages. Mussel secreted adhesion protein has strong adhesion capability, which inspires that the task group of Messer Smith at the northwest university in the United states in 2007 finds that Dopamine (DA) can be oxidized and self-polymerized into polydopamine on the surface of any material under the weak base condition simulating seawater. The polymerization condition is simple and controllable, and the product has excellent adhesiveness, hydrophilicity, stability and biocompatibility. Meanwhile, a large number of phenolic hydroxyl and amino active groups exist on the polydopamine, so that abundant active sites are provided for the complexation of metal ions.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a preparation method of a non-woven fabric for X and gamma ray protection.

The purpose of the invention can be realized by the following technical scheme:

the invention provides a preparation method of a non-woven fabric for X and gamma ray protection, which comprises the following steps:

(1) preparing a dopamine salt solution, adding a buffer solution to adjust the pH value, then adding tungsten powder, stirring, filtering, washing and drying to obtain W @ PDA;

(2) adding the W @ PDA obtained in the step (1) into a gadolinium nitrate solution, stirring, filtering, and calcining at high temperature to obtain W @ Gd of a core-shell structure₂O₃And (3) powder.

(3) Enabling the core-shell structure W @ Gd obtained in the step (2)₂O₃Sequentially adding the powder and the dried PP master batch into a feed port of a screw extruder to obtain the core-shell structure W @ Gd₂O₃the/PP is blended with the melt and cooled in the air for brittle fracture granulation.

(4) And (4) adding the dried blended particles obtained in the step (3) into a feed port of a screw extruder, and drawing the extruded melt by a drawing and winding device to prepare the composite fiber.

(5) Adding the pulp into a beaker filled with deionized water, and uniformly stirring to obtain pulp suspension.

(6) And (4) cutting the composite fiber obtained in the step (4) into short fibers, adding the short fibers into a wall breaking machine filled with deionized water, and breaking up all the fibers to obtain a fiber suspension.

(7) And (4) adding the pulp suspension obtained in the step (5) into the fiber suspension obtained in the step (6), and scattering until the fibers and the pulp are uniformly mixed and dispersed.

(8) And (4) pouring the mixed suspension obtained in the step (7) into a vacuum filtration device for filtration to obtain the wet-process formed felt.

(9) And (4) putting the felt obtained in the step (8) into a heating type manual tablet press for hot pressing to obtain a pressing sheet material, and drying to obtain the composite non-woven material.

According to the invention, the concentration of the prepared dopamine salt solution in the step (1) is controlled to be 1.5-2.5 g/L. Mainly because when the DA concentration is lower than 1.5g/L, only a small amount of PDA particles are deposited on the surface of W, and when the DA concentration is 1.5-2.5g/L, a PDA film is formed on the surface of W powder. When the concentration of DA is higher than 2.5g/L, larger PDA particles are formed on the surface of W powder through self-polymerization due to the fact that the concentration of DA is too high, and the subsequent adsorption of gadolinium ions is not facilitated.

It is noted that in the step (1), after the dopamine salt solution is prepared, a tris buffer solution is added into the system to adjust the pH value of the solution to 8-9, because dopamine can be polymerized into polydopamine by itself under the conditions of weak base and oxygen, and the polydopamine on the surfaces of different substances has extraordinary surface activity and adhesiveness, and can provide a platform for secondary functionalization of materials.

Further, the stirring in the step (1) needs to be carried out for 18-24 hours under an electric stirrer.

In addition, for the washing in step (1), washing with water and ethanol is required 2 to 3 times, respectively.

The specific conditions for the drying in step (1) are not particularly limited as long as the object of drying the sample can be achieved.

According to the invention, the concentration of the gadolinium nitrate solution in the step (2) should be controlled to be 0.3-0.5M/L. Because when Gd is present⁺At a concentration of 0.02M/L, the surface of W is coated with a small amount of sparse nano-dotted Gd₂O₃And (3) granules. When Gd is present⁺Gd on the W surface increased to 0.1M/L₂O₃The nanoparticles become larger and larger due to Gd⁺Increased concentration of Gd₂O₃The nanoparticles combine with each other to form larger Gd₂O₃And (3) granules. When Gd is present⁺Gd on the W surface increased to 0.2M/L₂O₃The nanoparticles become larger and more dense. With Gd⁺Gd increased in concentration to 0.3M/L, W surface₂O₃The nanoparticles combine with each other to form a coreW @ Gd of shell structure₂O₃. Continued increase in Gd⁺Gd on the W surface at a concentration of 0.4M/L₂O₃Nanoparticles compared to Gd⁺The concentration of 0.3M/L did not change much, due to poly-dopamine on the W surface to Gd⁺Chelating agents for Gd⁺The concentration of 0.3M/L is saturated, and the waste is caused by the excessively high concentration.

Further, the stirring in the step (2) is not particularly limited, and only magnetic stirring is needed for a certain time.

In addition, the high-temperature calcination in the step (2) needs to be carried out for 2-3h under the conditions of 800-1000 ℃ in a muffle furnace, and the temperature rise is 2-4 ℃/min. In order to avoid the formation of impurities during the reaction, the calcination in step (2) of the present invention is performed in a protective gas, wherein the protective gas includes nitrogen or an inert gas, and the inert gas may be argon, helium, etc., and the present invention is not particularly limited in this respect.

According to the invention, the PP master batch in the step (3) needs to be dried in an oven at 40-60 ℃ for 30-60 min.

In addition, the screw extruder in the step (3) has the extrusion temperature of 100 ℃ and the screw rotation speed of 15 r/min.

According to the invention, the blended particles in the step (4) are dried in an oven at 40-60 ℃ for 30-60 min.

It is noted that, in the screw extruder described in the step (4), the temperature of the screw zone is 100 ℃, the screw rotating speed is 20r/min, the temperature of the spinneret orifice is 85 ℃, the extrusion speed is as follows: 7-8 mm/min, and the aperture of a spinneret orifice is 2 mm.

In addition, the drafting and winding device in the step (4) has a drafting speed of 150 r/min.

According to the invention, the pulp of step (5) was 50ml of deionized water, with a pulp addition of 3 wt.%.

In addition, after the magnetic stirring is carried out for 5min at the stirring speed of 80r/min in the step (5), the stirring is carried out for 20min at the stirring speed of 40 r/min.

According to the invention, the short fiber in the step (6) has a length of 1-3 mm.

And (4) breaking the wall of the step (6), wherein the wall breaking machine is filled with 800ml of deionized water, pausing for 30s every 1min of breaking at a low speed, and repeating for 10 times.

According to the invention, the wall breaking machine in the step (7) breaks up, pauses for 30s every 1min at low speed, and repeats for 10 times.

According to the invention, the felt of step (8) has a diameter of 15 cm.

According to the hot press in the step (9), the rolling temperature of the upper plate and the lower plate is set to be 60 ℃, and the hot press is firstly carried out at 15000Pa for 1min, then at 20000Pa for 1min, then at 25000Pa for 30s and finally at 27500Pa for 30 s.

In addition, the drying in the step (9) needs to be carried out in an oven at 40-60 ℃ for 30-60 min.

As a preferable technical scheme, the preparation method of the non-woven fabric for X and gamma ray protection comprises the following steps:

(1) preparing 1.5-2.5g/L dopamine salt solution, adding tris buffer solution to adjust the pH value to 8-9, then adding tungsten powder cleaned by ethanol, stirring for 18-24h by using an electric stirrer, filtering and separating, washing for 2-3 times by using deionized water and ethanol respectively, and drying to obtain W @ PDA:

(2) adding the W @ PDA obtained in the step (1) into a gadolinium nitrate solution with the concentration range of 0.3-0.5M/L, magnetically stirring for a certain time, filtering, separating, drying, introducing nitrogen into the prepared sample at the temperature of 800-₂O₃And (3) powder.

(3) Enabling the core-shell structure W @ Gd obtained in the step (2)₂O₃Sequentially adding the powder and the dried PP master batch into a feed port of a screw extruder, wherein the extrusion temperature is 100 ℃, and the screw rotation speed is 15r/min, so as to obtain the core-shell structure W @ Gd₂O₃the/PP is blended with the melt and cooled in the air for brittle fracture granulation.

(4) Adding the dried blended particles obtained in the step (3) into a feed inlet of a screw extruder, wherein the temperature of a screw zone is 100 ℃, the rotating speed of the screw is 20r/min, the temperature of a spinneret orifice is 85 ℃, and the extrusion speed is as follows: 7-8 mm/min, the diameter of a spinneret orifice is 2mm, and then the extruded melt is drawn by a drawing and winding device at a drawing speed of 150r/min to prepare the composite fiber.

(5) Adding the pulp into a beaker filled with 50ml of deionized water, keeping the adding amount of the pulp at 3wt.%, carrying out magnetic stirring at the speed of 80r/min for 5min, and then stirring at the speed of 40r/min for 20min to obtain a uniform pulp suspension.

(6) And (3) shearing the composite fiber obtained in the step (4) into short fibers with the length of 1-3 mm, adding the short fibers into a wall breaking machine filled with 800mL of deionized water, pausing for 30s every 1min of low-speed scattering, and repeating for 10 times until all the fibers are scattered to obtain a fiber suspension.

(7) And (3) adding the pulp suspension obtained in the step (5) into the fiber suspension obtained in the step (6), pausing for 30s every 1min of scattering at a low speed, and repeating for 10 times until the fibers and the pulp are uniformly mixed and dispersed.

(8) And (4) pouring the mixed suspension obtained in the step (7) into a vacuum filtration device for filtration to obtain the wet-process formed felt with the diameter of 15 cm.

(9) Putting the felt obtained in the step (8) into a heating type manual tablet press for hot pressing, wherein the calendering temperature of the upper plate and the lower plate of the hot press is set as follows: and (3) when the temperatures of the upper plate and the lower plate are stabilized at 60 ℃, putting the felt between two heating and pressurizing plates of the heating type manual tablet press. Firstly carrying out hot pressing at 15000Pa for 1min, then carrying out hot pressing at 20000Pa for 1min, then carrying out hot pressing at 25000Pa for 30s, finally carrying out hot pressing at 27500Pa for 30s, and then placing the obtained pressing sheet material in an oven at 40 ℃ for drying for 30min to obtain the composite non-woven material.

The core-shell structure W @ Gd prepared by adopting the preferred technical scheme₂O₃Compared with tungsten and gadolinium oxide blended powder, the core-shell structure can play a synergistic protection role in radiation protection, and secondary radiation generated by radiation is effectively absorbed while a protection weak area is eliminated.

Compared with the prior art, the invention at least has the following beneficial effects:

according to the invention, dopamine is firstly utilized to be self-polymerized into poly-dopamine under the condition of weak base and oxygen, and the poly-dopamine has extraordinary adhesion on the surfaces of different substances, so that tungsten can be successfully coated, and W @ PDA is obtained.

The surface of PDA contains a large amount of polar groups such as phenolic hydroxyl, amido and the like, provides rich active sites for complexing various metal ions, and can effectively react with Gd in gadolinium nitrate solution⁺Chelation was performed. After high-temperature calcination, the PDA forms a nitrogen-doped carbon layer attached to the surface of tungsten and reacts with Gd⁺Conversion of chelating W @ PDA to W @ Gd₂O₃。

Drawings

FIG. 1 is a scanning electron microscope image of an X, gamma ray protective powder prepared in example 1.

Detailed Description

To better illustrate the invention and to facilitate the understanding of the technical solutions thereof, typical but non-limiting examples of the invention are as follows:

example 1

The embodiment provides a preparation method of a non-woven fabric for X and gamma ray protection, which comprises the following steps:

(1) preparing a dopamine salt solution with the concentration of 2g/L, adding a tris buffer solution to adjust the pH value of the solution to 8.5, then adding tungsten powder cleaned by ethanol, stirring for 24 hours by using an electric stirrer, filtering and separating, washing for 2 times by using deionized water and ethanol respectively, and drying for 5 hours at 80 ℃ to obtain W @ PDA;

(2) adding the W @ PDA obtained in the step (1) into a gadolinium nitrate solution with the concentration of 0.3M/L, magnetically stirring for 2 hours, filtering and separating, drying for 5 hours at 80 ℃, introducing nitrogen into the prepared sample at 800 ℃ and calcining at high temperature for 2 hours (the heating rate is 2 ℃/min), and finally obtaining the W @ Gd core-shell structure₂O₃And (3) powder.

(4) Adding the dried blended particles obtained in the step (3) into a feed inlet of a screw extruder, wherein the temperature of a screw zone is 100 ℃, the rotating speed of the screw is 20r/min, the temperature of a spinneret orifice is 85 ℃, and the extrusion speed is as follows: mm/min, the pore diameter of a spinneret orifice is 2mm, and then the extruded melt is drawn by a drawing and winding device under the condition of the drawing speed of 150r/min to prepare the composite fiber.

(6) And (3) shearing the composite fiber obtained in the step (4) into short fibers with the length of 1mm, adding the short fibers into a wall breaking machine filled with 800mL of deionized water, pausing for 30s at low speed every 1min for breaking, and repeating for 10 times until the fibers are completely broken to obtain a fiber suspension.

W @ Gd prepared in this example₂O₃The powder was SEM-scanned, and the photograph is shown in FIG. 1, in which it was found that a PDA film was formed on the surface of the W powder.

Example 2

(1) preparing 1.5g/L dopamine salt solution, adding tris buffer solution to adjust the pH value of the solution to 8, then adding tungsten powder cleaned by ethanol, stirring for 20 hours by using an electric stirrer, filtering and separating, washing for 3 times by using deionized water and ethanol respectively, and drying for 8 hours at 60 ℃ to obtain W @ PDA;

(2) adding the W @ PDA obtained in the step (1) into a gadolinium nitrate solution with the concentration of 0.35M/L, magnetically stirring for 3 hours, filtering and separating, drying for 8 hours at 60 ℃, introducing nitrogen into the prepared sample at 900 ℃ and calcining for 2.5 hours at high temperature (the heating rate is 3 ℃/min), and finally obtaining the W @ Gd of the core-shell structure₂O₃And (3) powder.

(4) Adding the dried blended particles obtained in the step (3) into a feed inlet of a screw extruder, wherein the temperature of a screw zone is 100 ℃, the rotating speed of the screw is 20r/min, the temperature of a spinneret orifice is 85 ℃, and the extrusion speed is as follows: 7.5mm/min, the pore diameter of a spinneret orifice is 2mm, and then the extruded melt is drawn by a drawing and winding device under the condition of the drawing speed of 150r/min to prepare the composite fiber.

(6) And (3) shearing the composite fiber obtained in the step (4) into short fibers with the length of 2mm, adding the short fibers into a wall breaking machine filled with 800mL of deionized water, pausing for 30s at low speed every 1min for breaking, and repeating for 10 times until the fibers are completely broken to obtain a fiber suspension.

Example 3

(1) preparing a dopamine salt solution with the concentration of 2.5g/L, adding a tris buffer solution to adjust the pH value of the solution to 9, then adding tungsten powder cleaned by ethanol, stirring for 18 hours by using an electric stirrer, filtering and separating, washing for 2 times by using deionized water and ethanol respectively, and drying for 6 hours at 70 ℃ to obtain W @ PDA;

(2) adding the W @ PDA obtained in the step (1) into a gadolinium nitrate solution with the concentration of 0.4M/L, magnetically stirring for 2.5h, filtering and separating, drying for 6h at 70 ℃, introducing nitrogen into the prepared sample at 1000 ℃ and calcining at high temperature for 3h (the heating rate is 4 ℃/min), and finally obtaining the W @ Gd of the core-shell structure₂O₃And (3) powder.

(4) Adding the dried blended particles obtained in the step (3) into a feed inlet of a screw extruder, wherein the temperature of a screw zone is 100 ℃, the rotating speed of the screw is 20r/min, the temperature of a spinneret orifice is 85 ℃, and the extrusion speed is as follows: 8mm/min, the pore diameter of a spinneret orifice is 2mm, and then the extruded melt is drawn by a drawing and winding device under the condition of the drawing speed of 150r/min to prepare the composite fiber.

(6) And (3) shearing the composite fiber obtained in the step (4) into short fibers with the length of 3mm, adding the short fibers into a wall breaking machine filled with 800mL of deionized water, pausing for 30s at low speed every 1min for breaking, and repeating for 10 times until the fibers are completely broken to obtain a fiber suspension.

The embodiments described above are intended to facilitate the understanding and use of the invention by those skilled in the art. It will be readily apparent to those skilled in the art that various modifications to these embodiments may be made, and the generic principles described herein may be applied to other embodiments without the use of the inventive faculty. Therefore, the present invention is not limited to the above embodiments, and those skilled in the art should make improvements and modifications within the scope of the present invention based on the disclosure of the present invention.

Claims

1. a preparation method of non-woven fabric for X, gamma ray protection, is characterized in that, described method may further comprise the steps:

(1) Prepare dopamine salt solution, add buffer to adjust pH value, then add tungsten powder, stir, filter, wash and dry to obtain W@PDA:

(2) adding the W@PDA obtained in step (1) into the gadolinium nitrate solution, stirring, filtering, and calcining at high temperature to obtain the core-shell structure W@Gd ₂ O ₃ powder;

(3) The core-shell structure W@Gd ₂ O ₃ powder obtained in step (2) and the dried PP masterbatch are sequentially added to the feed port of the screw extruder to obtain the core-shell structure W@Gd ₂ O ₃ /PP co-polymer. Mixed melt, brittle fracture granulation after cooling in air;

(4) adding the dry blended particles obtained in step (3) into the feed port of the screw extruder, and then stretching the extruded melt through a drafting and winding device to make composite fibers;

(5) Add the pulp into a beaker containing deionized water and stir evenly to obtain a pulp suspension;

(6) the composite fibers obtained in step (4) are cut into short fibers and then added to a wall breaker equipped with deionized water to disperse all the fibers to obtain a fiber suspension;

(7) adding the pulp suspension obtained in step (5) to the fiber suspension obtained in step (6), and beating it up until the fibers and pulp are mixed and dispersed evenly;

(8) pouring the mixed suspension obtained in step (7) into a vacuum filtration device for suction filtration to obtain a wet-processed felt;

(9) Putting the felt obtained in step (8) into a heated manual tablet press for hot pressing to obtain a tableting material and drying to obtain a composite non-woven material.

2 . The method for preparing a non-woven fabric for X and γ-ray protection according to claim 1 , wherein in step (1), a buffer is added to adjust the pH value, and the buffer is tris, and the pH Values are 8-9.

3 . The method for preparing a non-woven fabric for X-ray and γ-ray protection according to claim 1 , wherein the tungsten powder in step (1) is tungsten powder cleaned with ethanol. 4 .

4 . The method for preparing a non-woven fabric for X and γ ray protection according to claim 1 , wherein the stirring in step (1) is an electric stirrer stirring for 18-24 hours. 5 .

5 . The method for preparing a non-woven fabric for X-ray and γ-ray protection according to claim 1 , wherein the washing in step (1) is 2-3 times of washing with deionized water and ethanol respectively. 6 .

6 . The method for preparing a non-woven fabric for X-ray and γ-ray protection according to claim 1 , wherein the concentration of the dopamine salt solution in step (1) is 1.5g/L-2.5g/L. 7 .

7 . The preparation method of nonwoven fabric for X and γ rays protection according to claim 1 , wherein the high temperature calcination temperature in step (2) is 800-1000° C., the time is 2-3h, and the heating rate is 2-3 hours. 8 . 2-4°C/min.

8 . The method for preparing a nonwoven fabric for X and γ-ray protection according to claim 1 , wherein the calcination in step (2) is carried out in a protective gas, and the protective gas is nitrogen or an inert gas. 9 . gas.

9 . The method for preparing a non-woven fabric for X-ray and γ-ray protection according to claim 1 , wherein the concentration of the gadolinium nitrate solution in step (2) is 0.3-0.5M/L or more. 10 .

10. The preparation method of non-woven fabric for X and γ-ray protection according to claim 1, wherein in step (3), the PP masterbatch needs to be dried in an oven at 40-60°C for 30-60min .

11. The method for preparing non-woven fabrics for X and γ-ray protection according to claim 1, characterized in that, in the screw extruder of step (3), the extrusion temperature is 100°C, and the screw rotation speed is 15r/ min.

12 . The method for preparing a nonwoven fabric for X-ray and γ-ray protection according to claim 1 , wherein the blended particles in step (4) need to be dried in an oven at 40-60° C. for 30-60 minutes. 13 .

13 . The method for preparing a nonwoven fabric for X and γ-ray protection according to claim 1 , wherein, in the screw extruder of step (4), the temperature of the screw zone is 100° C., and the screw speed is 20 r/min, 13 . The spinneret hole temperature is 85°C, the extrusion speed: 7-8mm/min, and the spinneret hole diameter is 2mm.

14 . The method for preparing a non-woven fabric for X and γ-ray protection according to claim 1 , wherein in the drafting and winding device in step (4), the drafting speed is 150 r/min. 15 .

15 . The method for preparing a non-woven fabric for X and γ-ray protection according to claim 1 , wherein in step (5), the pulp is 50 ml of deionized water, and the amount of pulp added is 3 wt.%. 16 .

16. The preparation method of non-woven fabric for X and γ-ray protection according to claim 1, characterized in that, after the stirring in step (5) is performed at a speed of 80 r/min and magnetic stirring is performed for 5 min, the temperature is shifted to 40 r/min. Stir at the speed of min for 20 min.

17 . The method for preparing a nonwoven fabric for X-ray and γ-ray protection according to claim 1 , wherein the short fibers in step (6) are 1-3 mm in length. 18 .

18. The preparation method of non-woven fabric for X and γ-ray protection according to claim 1, characterized in that, in step (6), the wall breaker is broken up, and the wall breaker is equipped with 800ml of deionized water, and the low-speed Pause for 30s every 1min and repeat 10 times.

19. The preparation method of non-woven fabric for X and γ-ray protection according to claim 1, characterized in that, in step (7), the wall-breaking machine is used to break up, and every 1 min of breaking at a low speed is suspended for 30s, and is repeated 10 times. .

20 . The method for preparing a non-woven fabric for X-ray and γ-ray protection according to claim 1 , wherein the felt in step (8) has a diameter of 15 cm. 21 .

21. The method for preparing a non-woven fabric for X and γ-ray protection according to claim 1, wherein in the hot press in step (9), the calendering temperature of the upper and lower plates is set to 60°C, and the first 15000Pa Hot pressing for 1min, then 20000Pa for 1min, then 25000Pa for 30s, and finally 27500Pa for 30s.

22 . The method for preparing a non-woven fabric for X-ray and γ-ray protection according to claim 1 , wherein the drying in step (9) requires drying in an oven at 40-60° C. for 30-60 minutes. 23 .

23. The preparation method of the nonwoven fabric for X, gamma ray protection as claimed in any one of claims 1-22, wherein the method comprises the following steps:

(1) Prepare a dopamine salt solution with a concentration of 1.5g/L-2.5g/L, add tris buffer to adjust the pH to 8-9, then add tungsten powder cleaned with ethanol, stir with an electric stirrer for 18-24h and then filter Separate, then wash with deionized water and ethanol for 2-3 times and dry to obtain W@PDA;

(2) The W@PDA obtained in step (1) was added to a gadolinium nitrate solution with a concentration of 0.3-0.5M/L, and after magnetic stirring for a certain period of time, filtered and separated, dried, and then the prepared sample was heated at 800-1000 ℃. calcined at high temperature under nitrogen for 2-3h (heating rate of 2-4°C/min), and finally obtained the core-shell structure W@Gd ₂ O ₃ powder;

(3) The core-shell structure W@Gd ₂ O ₃ powder obtained in step (2) and the dried PP masterbatch were sequentially added to the feed port of the screw extruder, the extrusion temperature was 100 ° C, and the screw speed was 15 r/min , to obtain a core-shell structure W@Gd ₂ O ₃ /PP blend melt, which was cooled in air for brittle fracture granulation;

(4) Add the dried blended particles obtained in step (3) into the feed port of the screw extruder, the temperature of the screw zone is 100 ° C, the screw speed is 20 r/min, the temperature of the spinneret hole is 85 ° C, and the extrusion speed: 7～ 8mm/min, the diameter of the spinneret hole is 2mm, and then the extruded melt is stretched through a drawing and winding device under the condition of a drawing speed of 150r/min to make a composite fiber;

(5) Add the pulp into a beaker containing 50ml of deionized water, keep the pulp addition amount of 3wt.%, and perform magnetic stirring at a speed of 80r/min for 5min, then switch to a speed of 40r/min and stir for 20min to obtain a uniform solution. pulp suspension;

(6) Cut the composite fibers obtained in step (4) into short fibers with a length of 1-3 mm and then add them to a wall breaker equipped with 800 mL of deionized water, and pause for 30 s every 1 min at low speed, repeat 10 times until the The fibers are all dispersed to obtain a fiber suspension;

(7) Add the pulp suspension obtained in step (5) to the fiber suspension obtained in step (6), pause for 30s for every 1min at low speed, repeat 10 times until the fibers and pulp are mixed and dispersed evenly;

(8) Pour the mixed suspension obtained in step (7) into a vacuum filtration device for suction filtration to obtain a wet-processed felt with a diameter of 15 cm;

(9) Put the felt obtained in step (8) into a heated manual tablet press for hot pressing. The calendering temperature of the upper and lower plates of the hot press is set to: 60°C. When the temperature of the upper and lower plates is stabilized at 60°C, the The felt is placed in the middle of the two heating and pressing plates of the heated manual tableting machine; firstly, 15000Pa hot pressing for 1 min, then 20000Pa hot pressing for 1 min, then 25000Pa hot pressing for 30s, and finally 27500Pa hot pressing for 30s, and then the obtained tableting material is placed in 40 Dry in an oven at -60°C for 30-60min to obtain a composite non-woven material.