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Three-dimensional porous graphene aerogel wave-absorbing material and preparation method thereof

A graphene airgel and graphene hydrogel technology, which is applied in the direction of airgel preparation, graphene, chemical instruments and methods, etc., can solve the problems of complex preparation process, increased density of absorbing materials, and uneven pore size distribution , to achieve the effect of simple process, ultra-low filling amount and low cost

Active Publication Date: 2021-07-23
NANJING UNIV OF INFORMATION SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, in the preparation of three-dimensional graphene in the prior art, there are problems that the pore size is not easy to control and the pore size distribution is uneven, which leads to the unsatisfactory electromagnetic wave absorption performance of the three-dimensional graphene material.
At present, researchers mainly improve the microwave-absorbing performance of graphene aerogels by doping heteroatoms or introducing second-phase substances (dielectric materials, magnetic materials, etc.), but the above-mentioned strategies will increase the density of the absorbing material and increase the filling amount. increase, the preparation process is complicated, and the intrinsic softness and elasticity of graphene aerogels decay, etc.

Method used

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  • Three-dimensional porous graphene aerogel wave-absorbing material and preparation method thereof
  • Three-dimensional porous graphene aerogel wave-absorbing material and preparation method thereof
  • Three-dimensional porous graphene aerogel wave-absorbing material and preparation method thereof

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Effect test

Embodiment 1

[0025] Graphene oxide aqueous solution (3 mg / ml, 2ml), ascorbic acid (18mg) and ethanol (20mL) were measured, stirred by magnetic force, and dispersed ultrasonically in cold water to obtain a mixed solution. The mixed solution was transferred to a glass bottle and sealed, and placed in a 50°C oven for pre-reduction for 15 minutes to obtain a pre-reduced graphene hydrogel. The pre-reduced graphene hydrogel was frozen at -30 °C for 60 min, and then thawed at room temperature for 30 min to obtain the freeze-thawed pre-reduced graphene hydrogel. The freeze-thawed pre-reduced graphene hydrogel was sealed and placed in an oven at 95°C for 4 hours to obtain the graphene hydrogel. Put the hydrogel in an ethanol / water mixed solution (the volume ratio of ethanol and water is 1:4) and age for 24 h, then freeze at -60°C for 12 h, take it out and dry it in a freeze-drying equipment for 24 h. h, Obtained three-dimensional graphene airgel (sample 1). The prepared graphene airgel has a dens...

Embodiment 2

[0027] Measure graphene oxide aqueous solution (5 mg / ml, 2ml), sodium bisulfite (10mg) and methanol (200mL), stir magnetically, and disperse ultrasonically in cold water to obtain a mixed solution. The mixed solution was transferred to a glass bottle and sealed, and placed in an oven at 80 °C for pre-reduction for 120 min to obtain a pre-reduced graphene hydrogel. The pre-reduced graphene hydrogel was frozen at -50 °C for 45 min, and then thawed at room temperature for 45 min to obtain the pre-reduced graphene hydrogel after freeze-thawing. The freeze-thawed pre-reduced graphene hydrogel was sealed and placed in an oven at 80° C. for further reduction for 8 hours to obtain a graphene hydrogel. Put the hydrogel in an ethanol / water mixed solution (the volume ratio of ethanol and water is 1:5) and age for 48 h, then freeze at -60°C for 12 h, take it out and dry it in a freeze-drying equipment for 24 h. h, Obtained three-dimensional graphene airgel (sample 2). The prepared graph...

Embodiment 3

[0029] Measure graphene oxide aqueous solution (1 mg / ml, 2ml), hydriodic acid (10 mg) and isopropanol (100mL), stir magnetically, and disperse ultrasonically in cold water to obtain a mixed solution. The mixed solution was transferred to a glass bottle and sealed, and placed in a 95°C oven for pre-reduction for 60 min to obtain a pre-reduced graphene hydrogel. The pre-reduced graphene hydrogel was frozen at -70 °C for 10 min, and then thawed at room temperature for 60 min to obtain the freeze-thawed pre-reduced graphene hydrogel. The freeze-thawed pre-reduced graphene hydrogel was sealed and placed in an oven at 70 °C for 10 h to obtain graphene hydrogel. Put the hydrogel in an ethanol / water mixed solution (the volume ratio of ethanol and water is 1:6) and age for 72 h, then freeze at -60°C for 12 h, take it out and dry it in a freeze-drying equipment for 24 h. h, Obtained three-dimensional graphene airgel (sample 3). The prepared graphene airgel has a density of 8.50 mg / cm ...

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Abstract

The invention discloses a three-dimensional porous graphene aerogel wave-absorbing material and a preparation method thereof. The method comprises the following steps: respectively measuring a graphene oxide aqueous solution, a reducing agent and an anti-freezing agent, and obtaining a mixed solution after magnetic stirring and ultrasonic dispersion; transferring the mixed solution into a glass bottle, sealing and placing the glass bottle in a drying oven for pre-reduction to obtain pre-reduced graphene hydrogel; freezing the pre-reduced graphene hydrogel, and then unfreezing the pre-reduced graphene hydrogel at room temperature to obtain freeze-thawed pre-reduced graphene hydrogel; sealing the frozen and thawed pre-reduced graphene hydrogel and placing in a drying oven for continuous reduction, and obtaining graphene hydrogel; putting the graphene hydrogel into an ethanol / water mixed solution to be aged, performing freeze drying, and obtaining the three-dimensional graphene oxide aerogel. The pore size and the volume of the three-dimensional graphene wave-absorbing material can be freely controlled, and free design of absorption of different electromagnetic waves can be realized by controlling the pore size and the volume of the wave-absorbing material.

Description

technical field [0001] The invention relates to the field of preparation of wave-absorbing materials, in particular to a three-dimensional porous graphene airgel wave-absorbing material and a preparation method thereof. Background technique [0002] With the rapid development of electronic technology, TV broadcasting communication, microwave anechoic chamber, radar guidance and other technologies have been popularized and applied. As one of the effective means of reducing electromagnetic radiation, new absorbing materials have become a research hotspot in recent years. Regardless of the increasing demand for absorbing materials in the military or civilian fields, more and more attention has been paid to the application research on absorbing materials. As a new type of carbon material, graphene can meet the requirements of "thin, wide, light, and strong" new absorbing materials due to its special structure and properties, making it have a good application prospect in the fi...

Claims

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Application Information

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IPC IPC(8): C01B32/19C01B32/194C01B32/198B01J13/00
CPCC01B32/19C01B32/194C01B32/198B01J13/0091
Inventor 黄啸谷于高远邵高峰
Owner NANJING UNIV OF INFORMATION SCI & TECH
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