CN103556308B - Radiation shielding fiber and preparation method thereof - Google Patents

Abstract

The invention relates to a radiation shielding fiber and a preparation method thereof, wherein the radiation shielding fiber comprises the following raw material components in percentage by weight: 1-10% of ammonium tungstate, 5-20% of polyacrylonitrile copolymer and 70-95% of DMF; the preparation method of the radiation shielding fiber comprises the steps of preparing raw materials in proportion, feeding the raw materials in sequence to obtain a light yellow transparent clear homogeneous phase mixed solution, ultrasonically standing and defoaming to obtain a spinning solution, and then preparing fibril through dry spinning treatment; drying the obtained fibril, and pre-oxidizing the dried fibril in the presence of air; and carbonizing the protofiber subjected to preoxidation treatment in the atmosphere of nitrogen to obtain the radiation shielding fiber containing the metal tungsten nanoparticles. The beneficial effects of the implementation of the invention are as follows: the composite material not only has the performance of a fibrous material, but also has the radiation resistance function of metal tungsten, and products with different densities can be manufactured according to different proportions.

Description

A kind of radiation shielding fiber and its preparation method

technical field

The invention relates to the field of radiation protection materials, in particular to a radiation shielding fiber with ionizing radiation protection function and a preparation method thereof.

Background technique

With the rapid development of modern science and technology, various high-energy rays (such as X-rays) are more and more widely used in the fields of industry, agriculture, medicine, and national defense. While bringing huge economic and social benefits to people, the damage to human body and environment caused by these high-energy rays has become increasingly serious. Due to the continuous deepening of people's understanding of the biological effects of radiation, the protection of high-energy rays has attracted people's great attention. X-ray is a kind of ionizing radiation, which is different from general electromagnetic radiation, and it is more destructive to the human body. ICRP (International Commission on Radiological Protection) has listed X-rays as carcinogens, which have a significant impact on various metabolisms, hematopoietic functions, immune system, reproductive system and central nervous system of the human body, and can cause microcirculation disorders, canceration, Chromosomal aberrations, etc. Therefore, in order to prevent the carcinogenic effect of radiation and the genetic effect caused by cell mutation, it is imperative to protect against X-rays. X-ray protection can be used in three ways: time protection, distance protection and shielding protection. Shielding protection is to use or install a shielding material that can effectively absorb X-rays between the radiation source and personnel, thereby reducing or eliminating the harm of X-rays to the human body.

For X-ray protection material and prior art at present, mainly adopt the big metallic material of density to make shielding, come the ionizing radiation of protection X-ray, as with lead plate, lead rubber and the compound etc. that contain metallic lead, Such as patents CN200420114740.X, CN200620081066.9 and CN201220320504.8, etc. Although these materials can achieve the effect of protection, after all, these lead products are poor in comfort, and lead oxides are still toxic and pollute the environment. For this reason, developing a fiber with anti-X-ray and environmental protection has great application prospect.

Metal tungsten is a rare metal with a high melting point, and its chemical properties are very stable. Compared with metallic lead, its density (19.3g/cm3) is higher than that of lead (11.3g/cm3), and its effect of shielding ionizing radiation is better than that of lead. At the same time, it is non-toxic to the human body and will not cause environmental pollution. However, tungsten metal materials are difficult to form, and can only be processed into metal tungsten plates simply, and cannot be processed into protective devices or barriers with complex shapes. Chinese patent CN200710023999.1 reports a method for preparing a new composite material of metal and plastic, in which metal tungsten powder and plastic are blended and injection-molded to obtain a radiation shielding composite material.

At present, there is no patent report about the fiber containing metal tungsten with X-ray protection function.

Contents of the invention

The technical problem to be solved by the present invention is to provide a radiation shielding fiber and a preparation method thereof for the above-mentioned defects of the prior art.

The technical solution adopted by the present invention to solve the technical problem is: a radiation shielding fiber, the raw material components of the radiation shielding fiber include: ammonium tungstate: 1% to 10%; polyacrylonitrile copolymer: 5% to 10%. 20%; DMF: 70-95%.

Preferably, the ammonium tungstate salt includes at least one of ammonium orthotungstate, ammonium paratungstate and ammonium metatungstate.

Preferably, the polyacrylonitrile copolymer is acrylonitrile-acrylate polymer, acrylonitrile-methacrylate polymer, acrylonitrile-acrylic acid polymer, acrylonitrile-itaconic acid polymer, acrylonitrile-malay at least one of acid polymers.

A method for preparing a radiation shielding fiber, comprising the following steps:

S1. Using 1-10% by weight of ammonium tungstate salt, 5-20% by weight of polyacrylonitrile copolymer, and 70-95% by weight of DMF as raw materials, prepare the above raw materials into a mixed solution, Ultrasonic static defoaming of the mixed solution to obtain a spinning solution, and then dry-spinning the spinning solution to form fibrils;

S2. Drying the fibrils, and then pre-oxidizing the dried fibrils in air;

S3. Carbonizing the pre-oxidized fibrils in nitrogen to obtain radiation shielding fibers containing metal tungsten nanoparticles.

Preferably, the method for preparing the mixed solution in the step S1 is: first dissolving the polyacrylonitrile copolymer in DMF to form a DMF solution of the polyacrylonitrile copolymer, and then adding For ammonium tungstate salt, stir mechanically at a temperature of 25-100oC until the ammonium tungstate salt is completely dissolved, and the formed mixed solution of polyacrylonitrile copolymer and ammonium tungstate salt in DMF presents a transparent homogeneous phase , the mixed solution of polyacrylonitrile copolymer and ammonium tungstate salt in DMF that presents a transparent homogeneous phase is the mixed solution that can be subjected to subsequent ultrasonic static defoaming operations.

Preferably, the method of dry spinning treatment in the step S1 is: use a dry spinning device to perform dry spinning treatment, and the working parameters of the dry spinning treatment are: metering pump extrusion speed 20- 80ml/r, metering pump pressure less than 5.0MPa, hot shaft spinning temperature 100-400oC, nitrogen circulation 20-100ml/min, spinning speed 150-400m/min, washing temperature 60-90oC, draw ratio 3.3-6 times.

Preferably, in the step S2, the drying treatment on the fibrils is carried out in an environment with a temperature of 70-120°C.

Preferably, in the step S2, the method of performing the pre-oxidation treatment on the dried fibrils is: heat-treating the dried fibrils in a temperature range of 180-300oC, and the treatment time is 20 to 90 minutes.

Preferably, the method of the carbonization treatment in the step S3 is: heating the pre-oxidized fibrils in nitrogen, the heating temperature is between 400-1300°C, and the treatment time is 9-15 minutes.

The beneficial effect of implementing the present invention: the source of raw materials is convenient, the process is stable and reliable, the existing spinning and carbonization equipment is adopted as a whole, the product application is safe and non-toxic, and compared with the lead plate, tungsten plate, etc., the fiber has the characteristics of lightness, environmental protection, etc. ; A whole bundle or a single fiber with ionizing radiation protection effect has been obtained. The metal tungsten in the material is in the form of nanoparticles and tightly combined with the fiber, and will not fall off from the fiber. It has both the performance of the fiber and the metal tungsten. Anti-radiation function, and can produce products with different densities according to different ratios, and open up the application of metal tungsten materials in the field of fabrics.

Description of drawings

The present invention will be further described below in conjunction with accompanying drawing and embodiment, in the accompanying drawing:

Fig. 1 is the flowchart of the method embodiment 1 of the preparation method of a kind of radiation shielding fiber of the present invention;

Fig. 2 is a schematic structural view of a dry spinning device in Example 1 of a method for preparing a radiation shielding fiber of the present invention.

Detailed ways

Product Example 1

A radiation shielding fiber, the raw material components of the radiation shielding fiber include by weight percentage:

Ammonium tungstate: 1-10%; polyacrylonitrile copolymer: 5-20%; DMF (N,N-dimethylformamide): 70-95%.

In this embodiment, the ammonium tungstate salt refers to ammonium metatungstate.

In this embodiment, the polyacrylonitrile copolymer refers to acrylonitrile-methyl acrylate polymer (P(AN-MA)).

The weight ratio of P(AN-MA) to DMF is 1:4; the weight ratio of ammonium metatungstate to P(AN-MA) is 1:3, and the specific weight percentage data is: ammonium metatungstate: 6.25%; P (AN-MA) 18.75%; DMF: 75.00%.

Method embodiment 1:

A kind of preparation method of radiation shielding fiber, as shown in Figure 1, its preparation step comprises:

S1. Using 6.25% by weight of ammonium tungstate, 18.75% by weight of P(AN-MA), and 75.00% by weight of DMF as raw materials, the above raw materials are prepared into a mixed solution, and the mixed solution is ultrasonically Standing for defoaming, the spinning solution is obtained, and then the spinning solution is processed by dry spinning to make fibrils;

S2, drying the fibrils, and then pre-oxidizing the dried fibrils in air;

S3. Carbonizing the pre-oxidized fibrils in nitrogen to obtain radiation shielding fibers containing metal tungsten nanoparticles.

The order of feeding in the preparation step S1 is: first dissolve the P(AN-MA) powder in DMF to form a mixed solution, then add ammonium tungstate salt to the mixed solution of the two, and perform mechanical stirring at a temperature of 70oC. Until the ammonium tungstate salt is completely dissolved, and the formed mixed solution of P(AN-MA) and ammonium tungstate salt in DMF presents a transparent homogeneous phase, the mixed solution presenting a transparent homogeneous phase can be carried out Subsequent sonication left the spinning solution for defoaming operation.

The dry spinning process in the preparation step S1, the method uses a dry spinning device to perform the dry spinning process, as shown in Figure 2, the spinning solution 1 is stored in the sleeve 6 along the direction A, and the spinning At the same time, the spinning solution 1 flows through the metering pump 2, and then is extruded to the spinneret 3 for spinning. During this process, the hot nitrogen flow enters the hot shaft 4 along the B direction and flows out from the C direction. The spun The silk needs to be washed by the water washing device 5, and then stretched. The working parameters of the dry spinning process are: the extrusion speed of the metering pump is 20-80ml/r, the pressure of the metering pump is less than 5.0MPa, and the spinning temperature of the hot tunnel is 100- 400oC, nitrogen circulation 20-100ml/min, spinning speed 150-400m/min, washing temperature 60-90oC, draw ratio 3.3-6 times. In this embodiment, the metering pump extrusion speed is preferably 60ml/r, the metering pump pressure is preferably 4.0MPa, the hot tunnel spinning temperature is preferably 350°C, the nitrogen circulation rate is preferably 80ml/min, the spinning speed is preferably 250m/min, and the washing temperature is preferably 85oC, the stretch ratio is preferably 3.8 times.

For the drying treatment in the preparation step S2, the drying temperature is 70-120°C, so as to remove excess organic solvent in the fibrils. In this embodiment, the drying temperature is preferably 110°C.

The pre-oxidation treatment in the preparation step S2 is to heat-treat the dried fibrils at a temperature range of 180-300°C for 20-90 minutes to obtain fibrils with a trapezoidal ring structure. In this embodiment, the dried fibrils are placed in a muffle furnace for pre-oxidation. The pre-oxidation atmosphere is air, and the pre-oxidation temperatures are respectively 210, 250 and 290oC in three temperature zones, and each temperature zone is respectively Leave on for 20 minutes.

The carbonization treatment method described in step S3 is: heating the pre-oxidized fibrils in nitrogen, the heating temperature is between 400-1300oC, and the treatment time is 9-15 minutes. The so-called carbonization treatment means that the pre-oxidized fibrils are heated under the protection of nitrogen to transform the polymer fibers into carbon fibers, and the ammonium tungstate salt inside also decomposes metal tungsten. In this embodiment, the pre-oxidized fibrils are subjected to carbonization treatment under the protection of nitrogen atmosphere. The flow rate of nitrogen gas is 70ml/min. , 1050oC for 1 minute each, so as to obtain fibers with resistance to ionizing radiation.

The obtained fiber is obtained through a weaving process to obtain a plain gray cloth. The preferred weaving process is: a warp density of 60 threads/10cm and a weft density of 60 threads/10cm to obtain a micron gray cloth with a width of 100 cm and a thickness of 1 mm.

The evaluation of X-ray protection function adopts Siemens Multix ray source operating at 70kV, uses Radcal-MDH2025 ionization chamber dosimeter to measure the penetration dose at 15 cm below the sample, and calculates the equivalent lead plate thickness. The cumulative thickness of the fibers collected in this embodiment is 0.75 mm, and the equivalent lead plate thickness is 0.35 mm through X-ray evaluation.

These plain weave gray cloths are subjected to conventional follow-up treatment, that is, clothing and the like with anti-radiation shielding function can be prepared.

The beneficial effect of implementing the present invention: the source of raw materials is convenient, the process is stable and reliable, the existing spinning and carbonization equipment is adopted as a whole, the product application is safe and non-toxic, and compared with the lead plate, tungsten plate, etc., the fiber has the characteristics of lightness, environmental protection, etc. . A whole bundle or a single fiber with ionizing radiation protection effect is obtained, and the metal tungsten in the fiber material is in the form of nanoparticles and closely combined with the fiber, and will not fall off from the fiber. It not only has the performance of fiber, but also has the anti-radiation function of metal tungsten, and can produce products with different densities according to different proportions, and develops the application of metal tungsten materials in the field of fabrics.

The present invention is further described above in conjunction with specific embodiments. However, these examples are only used to illustrate the present invention rather than limit the scope of the present invention. In addition, it should be understood that after reading the content of the present invention, those skilled in the art may make various changes and modifications to the present invention, and these equivalent forms also fall within the scope defined in the appended claims of the present application.

Claims (9)

1. A preparation method for radiation shielding fibers, comprising the following steps: S1. Using 1-10% by weight of ammonium tungstate salt, 5-20% by weight of polyacrylonitrile copolymer, and 70-95% by weight of DMF as raw materials, prepare the above raw materials into a mixed solution, Ultrasonic static defoaming of the mixed solution to obtain a spinning solution, and then dry-spinning the spinning solution to form fibrils; S2. Drying the fibrils, and then pre-oxidizing the dried fibrils in air; S3. Carbonizing the pre-oxidized fibrils in nitrogen to obtain radiation shielding fibers containing metal tungsten nanoparticles. 2. The preparation method of the radiation shielding fiber according to claim 1, characterized in that, the method for preparing the mixed solution in the step S1 is: first dissolving the polyacrylonitrile copolymer in DMF to form a polyacrylonitrile copolymer DMF solution of polyacrylonitrile copolymer, then add ammonium tungstate salt to the DMF solution of polyacrylonitrile copolymer, and mechanically stir at a temperature of 25-100°C until the ammonium tungstate salt is completely dissolved, and the formed polyacrylonitrile copolymer The mixed solution of polyacrylonitrile copolymer and ammonium tungstate salt in DMF presents a transparent homogeneous phase, and the mixed solution of polyacrylonitrile copolymer and ammonium tungstate salt in DMF that presents a transparent homogeneous phase is ready for subsequent ultrasonic Set aside the mixed solution for defoaming operation. 3. The method for preparing radiation shielding fibers according to claim 1, characterized in that, the method of dry spinning treatment in the step S1 is: use a dry spinning device to perform dry spinning treatment, and The working parameters of dry spinning treatment are: metering pump extrusion speed 20-80ml/r, metering pump pressure less than 5.0MPa, hot tunnel spinning temperature 100-400℃, nitrogen circulation 20-100ml/min, spinning speed 150-400m/min, washing temperature 60-90℃, stretching ratio 3.3-6 times. 4. The method for preparing radiation shielding fibers according to claim 1, characterized in that, in the step S2, the drying treatment of the fibrils is carried out in an environment with a temperature of 70-120°C . 5. The preparation method of the radiation shielding fiber according to claim 1, characterized in that, in the step S2, the method of performing the pre-oxidation treatment on the dried fibrils is: The fibrils are heat-treated in the temperature range of 180-300° C., and the treatment time is 20-90 minutes. 6. The preparation method of radiation shielding fiber according to claim 1, characterized in that, the carbonization treatment method described in step S3 is: heating the pre-oxidized fibrils in nitrogen to a temperature of Between 400～1300℃, the treatment time is 9-15 minutes. 7. A radiation shielding fiber based on the preparation method of radiation shielding fiber according to claim 1, characterized in that, the raw material components of the radiation shielding fiber include: ammonium tungstate: 1% to 10%; Acrylonitrile copolymer: 5-20%; DMF: 70-95%. 8. The radiation shielding fiber according to claim 7, wherein the ammonium tungstate salt comprises at least one of ammonium orthotungstate, ammonium paratungstate and ammonium metatungstate. 9. The radiation shielding fiber of claim 7, wherein the polyacrylonitrile copolymer is an acrylonitrile-acrylate polymer, an acrylonitrile-methacrylate polymer, an acrylonitrile-acrylic acid polymer, At least one of acrylonitrile-itaconic acid polymer and acrylonitrile-maleic acid polymer.