Preparation method of magnetic particle doped coal pitch-based porous carbon wave-absorbing material

Abstract

The application discloses a preparation method of a magnetic particle doped coal pitch based porous carbon wave absorbing material, and belongs to the technical field of electromagnetic wave absorption. The preparation method of the magnetic particle doped coal pitch based porous carbon wave absorbing material comprises the following steps: dissolving coal pitch in a crosslinking agent under an inert gas atmosphere, then adding a catalyst, reacting to obtain a precipitate, extracting the precipitate in a soxhlet extractor after washing, and performing vacuum drying on the obtained powder to obtain a coal pitch based hypercrosslinked polymer; dissolving the coal pitch based hypercrosslinked polymer, nickel nitrate hexahydrate and urea in anhydrous ethanol to obtain a mixed solution, then performing refluxing, cooling, washing and precipitating, vacuum drying the obtained powder, and then placing the powder in a tube furnace to perform heating; and thus, the magnetic carbon based composite wave absorbing material with a three-dimensional porous structure is efficiently prepared by using a simple refluxing process.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of electromagnetic wave absorption, and particularly relates to a preparation method of a magnetic particle doped coal pitch based porous carbon wave absorbing material. BACKGROUND

[0002] With the wide application of 5G communication, wireless transmission, information processing and radar stealth technologies, electromagnetic technology has greatly promoted the innovation and development of human society, and has brought great convenience to human travel, communication, entertainment and the like. However, at the same time, it has also brought serious electromagnetic radiation pollution. Electromagnetic wave absorbing materials can effectively absorb and protect electromagnetic waves, so developing new high-efficiency electromagnetic wave absorbing materials is an effective way to prevent and control electromagnetic pollution. Electromagnetic wave absorbing materials of a single loss type are difficult to achieve high-efficiency and wide-band absorption performance. Therefore, the research focus of the current wave absorbing materials is mainly to combine two types of loss materials to prepare high-performance wave absorbing composite materials.

[0003] In recent years, magnetic carbon-based composite wave absorbing materials have gradually entered the field of view of researchers due to their magnetic loss and dielectric loss. At the same time, the combination of magnetic particles and carbon materials brings a large number of interfaces, which may cause the accumulation of electrons at the heterojunction, which is beneficial to the enhancement of dielectric loss. At the same time, the addition of magnetic fillers can significantly compensate for the lack of magnetic loss of dielectric loss type materials, further enhancing the electromagnetic wave absorption performance.

[0004] However, the conventional method for constructing magnetic porous carbon materials usually relies on complex processes such as hydrothermal reaction and freeze-drying, which has a high preparation cost and is not conducive to the practical application of composite materials. Therefore, it is still an important exploration direction in this field to construct three-dimensional magnetic porous carbon materials with good wave absorbing performance by a simple method. SUMMARY

[0005] In view of the deficiencies of the prior art, the purpose of the present application is to provide a preparation method of a magnetic particle doped coal pitch based porous carbon wave absorbing material, which solves the problems in the prior art.

[0006] The purpose of the present application can be achieved by the following technical solutions:

[0007] A preparation method of a magnetic particle doped coal pitch based porous carbon wave absorbing material, comprising the following steps:

[0008] S1, under an inert gas atmosphere, dissolving coal pitch in a crosslinking agent, then adding a catalyst, and obtaining a precipitate by reaction, and then extracting the precipitate in a soxhlet extractor after washing, and drying the obtained powder under reduced pressure to obtain a coal pitch based hypercrosslinked polymer;

[0009] S2, coal tar pitch hypercrosslinked polymer, nickel nitrate hexahydrate and urea are dissolved in anhydrous ethanol to obtain a mixed solution, which is then refluxed, cooled and washed to precipitate. The resulting powder is then vacuum dried and heated in a tube furnace to obtain a magnetic particle-doped coal tar pitch-based porous carbon composite material.

[0010] Furthermore, the inert gas is argon or nitrogen.

[0011] Furthermore, the crosslinking agent is chloroform.

[0012] Furthermore, the catalyst is aluminum trichloride.

[0013] Further, in S1, after washing the precipitate, it is extracted with ethanol and chloroform in a Sogret extractor.

[0014] Furthermore, the vacuum drying in S1 is carried out at a temperature of 80°C for 24 hours.

[0015] Furthermore, in S2, the mixed solution is refluxed in a round-bottom flask at a temperature of 100°C for 12 hours.

[0016] Furthermore, in S2, the vacuum drying temperature of the powder is 80°C.

[0017] Furthermore, in S2, the powder is placed in a tube furnace under an inert gas protective atmosphere and held at 700°C for 4 hours at a heating rate of 5°C / min.

[0018] A porous carbon microwave absorbing material based on coal tar pitch and doped with magnetic particles was prepared using the above-described preparation method.

[0019] The beneficial effects of this invention are:

[0020] 1. Using coal tar pitch as a carbon source to prepare porous carbon materials is a new approach to coal tar pitch deep processing technology, which is conducive to the refined, efficient and high-value-added utilization of resources.

[0021] 2. By rationally designing the composition of porous carbon materials and preparing magnetic / porous carbon-based composite materials by combining them with magnetic nanoparticles, the problem of magnetic loss in porous carbon materials can be improved, thereby effectively enhancing the ability of porous carbon-based materials to attenuate incident electromagnetic waves.

[0022] 3. A magnetic carbon-based composite microwave absorbing material with a three-dimensional porous structure was efficiently prepared using a simple reflux process. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a scanning electron microscope image of the magnetic particle-doped coal tar pitch-based porous carbon composite microwave absorbing material of the present invention;

[0025] Figure 2 This is a reflection loss diagram of the magnetic particle-doped coal tar pitch-based porous carbon composite microwave absorbing material of the present invention. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] Example 1

[0028] A method for preparing a magnetic particle-doped coal tar pitch-based porous carbon microwave absorbing material includes the following steps:

[0029] S1. Under an argon atmosphere, coal tar pitch is dissolved in chloroform crosslinking agent, and then a certain amount of AlCl3 catalyst is added. The reaction is carried out at 58°C for 24 hours. The precipitate is washed three times with ethanol, and then extracted with ethanol and chloroform in a Sogret extractor for 12 hours. Finally, the powder is dried under reduced pressure at 80°C for 24 hours to obtain the coal tar pitch-based hypercrosslinked polymer.

[0030] S2, 0.1 g of coal tar pitch hypercrosslinked polymer, 3 mmol of nickel nitrate hexahydrate (Ni(NO3)2·6H2O) and urea (mass ratio of urea to nickel nitrate hexahydrate is 1:1) were fully dissolved in anhydrous ethanol to obtain a homogeneous solution; then, the solution was refluxed at 100 °C for 12 h in a round-bottom flask, cooled to room temperature, and the precipitate was washed with anhydrous ethanol. The resulting powder was then vacuum dried overnight at 80 °C; subsequently, the powder was placed in a tube furnace and heated at 700 °C for 4 h at a heating rate of 5 °C / min under an argon protective atmosphere to obtain magnetic particle-doped coal tar pitch-based porous carbon composite material (Ni / C).

[0031] In this embodiment, the scanning electron microscope (SEM) image of the prepared Ni / C composite material is shown below. Figure 1As shown, scanning electron microscopy revealed that metallic Ni particles were successfully loaded onto a porous carbon framework.

[0032] Example 2

[0033] In this embodiment, the electromagnetic wave absorption performance of the Ni / C composite material prepared by the preparation method of Example 1 was tested.

[0034] like Figure 2 As shown, the prepared Ni / C composite material has excellent electromagnetic wave absorption performance. When the thickness is 1.9 mm and the frequency is 11.84 GHz, the minimum reflection loss is -44.84 dB; when the thickness is reduced to 1.5 mm, the maximum absorption bandwidth is 3.92 GHz (13.36-17.2 GHz).

[0035] In summary, this work prepared Ni-doped coal tar pitch-based porous carbon composite materials using a simple high-temperature reflow process. The introduction of magnetic particles enhanced the magnetic loss capability of the porous carbon material and further improved its impedance matching characteristics. The results show that the Ni@C composite material exhibits the best electromagnetic wave absorption performance with a reflection loss of -44.84 dB at a thickness of 1.9 mm. Furthermore, at a lower matching thickness of 1.5 mm, the maximum effective absorption bandwidth is 3.92 GHz (13.36–17.2 GHz).

[0036] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0037] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A method for preparing a porous carbon microwave absorbing material based on coal tar pitch and doped with magnetic particles, characterized in that, Includes the following steps: S1, under an inert gas atmosphere, coal tar pitch is dissolved in a crosslinking agent, then a catalyst is added, and the reaction yields a precipitate. After washing, the precipitate is extracted in a Sogret extractor, and the resulting powder is dried under reduced pressure to obtain a coal tar pitch-based hypercrosslinked polymer. S2, coal tar pitch supercrosslinked polymer, nickel nitrate hexahydrate and urea are dissolved in anhydrous ethanol to obtain a mixed solution, and then the solution is refluxed, cooled and washed to precipitate. The resulting powder is then vacuum dried and heated in a tube furnace to obtain a magnetic particle doped coal tar pitch based porous carbon composite material. In S2, the powder is placed in a tube furnace under an inert gas protective atmosphere and held at 700°C for 4 hours at a heating rate of 5°C / min.

2. The method for preparing a magnetic particle-doped coal tar pitch-based porous carbon microwave absorbing material according to claim 1, characterized in that, The inert gas is argon or nitrogen.

3. The method for preparing a magnetic particle-doped coal tar pitch-based porous carbon microwave absorbing material according to claim 1, characterized in that, The crosslinking agent is trichloromethane.

4. The method for preparing a magnetic particle-doped coal tar pitch-based porous carbon microwave absorbing material according to claim 1, characterized in that, The catalyst is aluminum trichloride.

5. The method for preparing a magnetic particle-doped coal tar pitch-based porous carbon microwave absorbing material according to claim 1, characterized in that, In S1, after washing the precipitate, it was extracted with ethanol and chloroform in a Sogret extractor.

6. The method for preparing a magnetic particle-doped coal tar pitch-based porous carbon microwave absorbing material according to claim 1, characterized in that, The vacuum drying in S1 is carried out at a temperature of 80℃ for 24 hours.

7. The method for preparing a magnetic particle-doped coal tar pitch-based porous carbon microwave absorbing material according to claim 1, characterized in that, In S2, the mixed solution is refluxed in a round-bottom flask at a temperature of 100°C for 12 hours.

8. The method for preparing a magnetic particle-doped coal tar pitch-based porous carbon microwave absorbing material according to claim 1, characterized in that, In S2, the vacuum drying temperature of the powder is 80℃.

9. A porous carbon microwave absorbing material based on coal tar pitch and doped with magnetic particles, characterized in that, It was prepared using the preparation method described in any one of claims 1-8.

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