Magnetic carbon nanofiber aerogel wave-absorbing material and preparation method

A technology of carbon nanofibers and nanofibers, applied in the field of wave-absorbing materials, can solve problems such as unfavorable interface polarization and related losses, hierarchical porous structure damage, low-efficiency utilization of fillers, etc., to improve application value, strong magnetic loss, strong The effect of interface polarization

Inactive Publication Date: 2020-02-18
SHANGHAI JIAO TONG UNIV
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  • Abstract
  • Description
  • Claims
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Problems solved by technology

[0004] However, in the preparation process of the existing composite absorbing materials made of biomass materials, the natural three-dimensional network structure is destroyed during the process of grinding the biomass materials into powder, and short fibers with disorderly distribution are formed. or particles, although the surface adsorbs magnetic nanoparticles, the high conductivity threshold required to achieve excellent absorbing properties limits their practical applications
At the same time, for common biomass materials, the porous carbon formed after carbonization, on the one hand, when it is used as a wave-absorbing material, physical grinding leads to the destruction of the hierarchical porous structure, which is not conducive to interface polarization and related losses; on the other hand, it lacks Higher aspect ratio microstructures result in porous carbons achieving optimum absorption properties only at higher loadings, resulting in inefficient use of fillers

Method used

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  • Magnetic carbon nanofiber aerogel wave-absorbing material and preparation method
  • Magnetic carbon nanofiber aerogel wave-absorbing material and preparation method
  • Magnetic carbon nanofiber aerogel wave-absorbing material and preparation method

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Embodiment 1

[0047] see figure 1 as shown, figure 1 The scanning electron microscope schematic diagram of a magnetic carbon nanofiber airgel wave-absorbing material provided by the embodiment of the present invention, the present invention discloses a magnetic carbon nanofiber airgel wave-absorbing material, including carbon nanofiber 1 and magnetic nanoparticles 2. Magnetic nanoparticles 2 are dispersed on the carbon nanofibers 1, wherein the carbon nanofibers 1 are obtained by pyrolysis of biomass materials, the fiber diameter of the carbon nanofibers 1 is 30-50 nm, and the aspect ratio of the carbon nanofibers 1 is 1000-3000, the magnetic carbon nanofiber airgel wave-absorbing material provided by the present invention has a high aspect ratio, and a porous network structure constructed by interlaced fibers is formed inside it, which is conducive to the construction of a conductive network under low fillers, and can be obtained under low fillers. The best wave-absorbing performance, low...

Embodiment 2

[0053] Based on the same inventive idea, see Figure 4 as shown, Figure 4 It is a flowchart of a method for preparing a magnetic carbon nanofiber airgel wave-absorbing material provided by an embodiment of the present invention. The present invention also provides a method for preparing a magnetic carbon nanofiber airgel wave-absorbing material, including the following steps :

[0054] A1, obtaining purified biomass materials for preparing magnetic carbon nanofiber airgel wave-absorbing materials through solution processing;

[0055] A2, soaking the purified biomass material in the transition metal salt solution to obtain the first precursor product, the soaking time is 24-72h, preferably 48h. In this embodiment, the transition metal salt solution is any one of iron, cobalt, nickel nitrate, sulfate, or two or more salt solutions, and the concentration of the transition metal salt solution is 0.01 to 0.05 mol / L, preferably 0.02mol / L, the introduced magnetic nanoparticles ca...

Embodiment 3

[0072] Based on the same inventive concept, this embodiment provides a method for preparing a specific magnetic carbon nanofiber airgel wave-absorbing material, which includes the following steps:

[0073] Step 1: Cut the bacterial cellulose with a thickness of 15mm into small pieces of 5cm*3cm, put it in a NaOH solution with a mass fraction of 1.94wt%, keep it in a water bath at 100°C for 2 hours, and then put it in an ultrasonic cleaner for ultrasonication Treat for 1 hour, and repeat the treatment twice in this way;

[0074] Step 2: put the product obtained in the above step 1 into an acetic acid solution with a mass fraction of 1.5wt%, keep it in a water bath at 100° C. for 2 hours, put it into an ultrasonic cleaning machine for ultrasonic treatment for 1 hour, and use this The method is repeated twice;

[0075] Step 3: the purified bacterial cellulose that step 2 obtains is put into 500mL Ni(NO 3 ) 2 In solution, Ni(NO 3 ) 2 The concentration of the solution is 0.02m...

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Abstract

The invention discloses a magnetic carbon nanofiber aerogel wave-absorbing material, which includes carbon nanofibers and magnetic nanoparticles. The magnetic nanoparticles are dispersed on the carbonnanofibers. The carbon nanofibers are carbon nanofibers pyrolyzed by a biomass material, have fiber diameters of 30 to 50 nm and an aspect ratio of 1000 to 3000. The magnetic carbon nanofiber aerogelwave-absorbing material provided by the present invention has a high aspect ratio, and has a porous network structure formed therein by staggered fibers so as to contribute to the construction of a conductive network under low fillers, and obtain the best wave-absorbing performance under low fillers. Further, the porous network structure filled with low fillers and formed by the staggered fibersprovides the magnetic carbon nanofiber aerogel wave-absorbing material with light and flexible features, improves the application value of the wave-absorbing material. In addition, the wave-absorbingmaterial has strong interfacial polarization and magnetic loss so as to contribute to the loss of incident electromagnetic waves.

Description

technical field [0001] The invention relates to the field of wave-absorbing materials, in particular to a magnetic carbon nanofiber airgel wave-absorbing material and a preparation method. Background technique [0002] With the development of science and technology and the electronic industry, the application of various electronic devices has gradually increased, and electromagnetic wave radiation has become a new social hazard. On the one hand, the radiated electromagnetic waves will affect the normal operation of the surrounding electrical equipment and systems. On the other hand, long-term exposure to electromagnetic wave radiation will seriously affect people's physical and mental health. As an effective electromagnetic wave absorber, the microwave-absorbing material is increasingly prominent in the field of modern science and technology. First of all, having strong absorption capacity in the required absorption band is the basic requirement for absorbing materials. In ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H05K9/00
CPCH05K9/0081
Inventor 刘庆雷梁亮亮张子强张旺张荻
Owner SHANGHAI JIAO TONG UNIV
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