A kind of preparation method of carbon nanotube/cellulose lightweight wave-absorbing foam

A technology of carbon nanotubes and multi-walled carbon nanotubes, which is applied in chemical instruments and methods, ceramic products, and other chemical processes, and can solve the problems of high density, complex preparation process of wave-absorbing foam, and difficult control of electromagnetic wave absorption/shielding performance, etc. question

Active Publication Date: 2020-11-06
NORTHWESTERN POLYTECHNICAL UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] In order to avoid the deficiencies of the prior art, the present invention proposes a method for preparing a carbon nanotube / cellulose light-weight wave-absorbing foam, aiming at the complex preparation process, high density, and difficult electromagnetic wave absorption / shielding performance of the existing wave-absorbing foam. Disadvantages such as regulation

Method used

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  • A kind of preparation method of carbon nanotube/cellulose lightweight wave-absorbing foam
  • A kind of preparation method of carbon nanotube/cellulose lightweight wave-absorbing foam
  • A kind of preparation method of carbon nanotube/cellulose lightweight wave-absorbing foam

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Effect test

Embodiment 1

[0024] Put 3g of multi-walled carbon nanotubes in 97ml of deionized water, and ultrasonically disperse for 3 hours to obtain a uniformly dispersed aqueous dispersion of multi-walled carbon nanotubes; place 1g of nanocellulose fibers in 99ml of deionized water, and ultrasonically disperse for 1h to obtain nanofibers cellulose aqueous solution; put 10ml multi-walled carbon nanotube aqueous dispersion in 70ml nanocellulose fiber aqueous solution, and ultrasonicate for 1.5h to obtain a mixed solution; put the mixed solution in a cube-shaped mold, and cool down to -60°C at 5°C / min Pre-freeze for 6 hours at ℃, and dry for 30 hours under 0.1Pa vacuum condition. The carbon nanotube / cellulose light wave-absorbing foam can be obtained after demoulding. When the thickness of the prepared foam varies within the range of 5.3-6.8mm, it has excellent absorbing properties in the X-band range that can effectively absorb and cover all frequency bands (EAB=4.2GHz, and can absorb more than 99% of...

Embodiment 2

[0026] Put 1.5g of single-walled carbon nanotubes in 98.5ml of deionized water, and ultrasonically disperse for 5 hours to obtain a uniformly dispersed single-walled carbon nanotube aqueous dispersion; place 0.5g of carboxymethyl cellulose in 99.5ml of deionized water, and ultrasonically disperse 1h to obtain an aqueous solution of carboxymethyl cellulose; put 50ml of single-walled carbon nanotube aqueous dispersion in 20ml of aqueous carboxymethylcellulose, and ultrasonicate for 2h to obtain a mixed solution; place the mixed solution in a cuboid mold and heat / min to -60°C for pre-freezing for 8 hours, and dried for 40 hours under 0.1Pa vacuum condition. The carbon nanotube / cellulose light wave-absorbing foam can be obtained after demoulding. The prepared foam has an electromagnetic wave shielding performance greater than 37dB in the X-band. Its electromagnetic shielding performance is as figure 2 as shown in b.

Embodiment 3

[0028] Put 2g of aminated carbon nanotubes in 98ml of deionized water, and ultrasonically disperse for 4h to obtain a uniformly dispersed aqueous dispersion of aminated carbon nanotubes; put 1.5g of carboxymethyl cellulose in 98.5ml of deionized water, and ultrasonically disperse for 2h, Obtain an aqueous solution of carboxymethyl cellulose; put 30ml of single-walled carbon nanotube aqueous dispersion in 50ml of aqueous carboxymethyl cellulose, and ultrasonicate for 2 hours to obtain a mixed solution; Lower the temperature to -60°C for pre-freezing for 6 hours, and dry for 36 hours under 0.1Pa vacuum condition. The carbon nanotube / cellulose light wave-absorbing foam can be obtained after demolding. The prepared foam has excellent absorbing performance at X.

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Abstract

The invention relates to a preparation method of lightweight carbon-nanotube / cellulose wave-absorbing foam, and specifically includes preparation of an aqueous carbon-nanotube dispersion solution andan aqueous cellulose solution. The lightweight carbon-nanotube / cellulose wave-absorbing foam is prepared by the following steps of mixing the aqueous carbon-nanotube dispersion solution and the aqueous cellulose solution by adopting the technologies, including ultrasonic stirring and the like, so as to obtain uniformly dispersed liquid; and then, performing freeze-drying on the dispersed liquid ina mould so as to obtain the lightweight carbon-nanotube / cellulose wave-absorbing foam. The lightweight carbon-nanotube / cellulose wave-absorbing foam is prepared from non-toxic raw materials which canbe easily obtained; and the preparation method is simple, controllable in processes, low in cost and good in repeatability. The prepared wave-absorbing foam has the advantages of being wide, strong,light, thin and adjustable in dielectrical properties; and thus, the wave-absorbing foam is suitable for the fields of electromagnetic wave absorption / shielding and the like.

Description

technical field [0001] The invention belongs to the technical field of manufacturing carbon nanometer functional materials, and relates to a preparation method of carbon nanotube / cellulose light wave-absorbing foam. Background technique [0002] Due to the advantages of strong designability, light weight and simple process, foam materials have received extensive attention and research in the field of electromagnetic wave absorption / shielding. Patent CN103923337 discloses a PMI composite foam wave-absorbing material, which is made by mixing wave-absorbing agent and expandable PMI resin particles with a specific binder and then foaming. However, the process is complex, requiring more than 10 types of materials, and the density of the prepared foam is relatively high, which limits its practical application. Patent CN201710250796.X discloses a lightweight broadband PMI foam and its preparation method, which has good wave-absorbing performance, but the preparation process is com...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C04B26/28C04B14/02C04B38/00C09K3/00
CPCC04B14/026C04B26/285C04B38/00C09K3/00C04B22/002
Inventor 殷小玮许海龙李新亮张立同成来飞
Owner NORTHWESTERN POLYTECHNICAL UNIV
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