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Composite microwave absorber and preparation method thereof

A microwave absorber and carbon nanofiber technology, which is applied in chemical instruments and methods, other chemical processes, textiles and papermaking, etc., can solve the problems of high energy consumption in the preparation process, unsatisfactory microwave performance, and low output, and achieve process performance. Low energy consumption, light weight, and improved absorption performance

Active Publication Date: 2020-09-01
安徽璜峪电磁技术有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0006] Aiming at the deficiencies of the prior art, the present invention provides a composite microwave absorber and its preparation method, which solves the unsatisfactory microwave performance of the composite nanofiber microwave absorber in the prior art, high energy consumption of the preparation process, and low output

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  • Composite microwave absorber and preparation method thereof
  • Composite microwave absorber and preparation method thereof
  • Composite microwave absorber and preparation method thereof

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preparation example Construction

[0041] On the other hand, the embodiment of the present invention also provides a preparation method of the composite microwave absorber, comprising the following steps:

[0042] S1. The carbon nanofibers are collected by centrifugation after acidification treatment, washed repeatedly and then dried; in specific implementation, during the acidification treatment process of the carbon nanofibers, the concentration of the carbon nanofibers in the acid is 2-6 mg / mL;

[0043] S2. Disperse the acidified carbon nanofibers in methanol solution, add methanol solution of cobalt nitrate, and magnetically stir; in the specific implementation process, the above dispersion process can be combined with ultrasonic action to promote dispersion;

[0044] S3. Under the condition of magnetic stirring, add a methanol solution of 2-methylimidazole to the mixed solution in step S2, centrifuge after the reaction is completed, and then use methanol to wash repeatedly and then dry; in the process of sp...

Embodiment 1

[0060] Example 1: Weigh 5g of carbon nanofibers, measure 1250mL of concentrated nitric acid and slowly add to the above solid, stir magnetically in a water bath at 90°C for 0.5h, cool and stir at room temperature for 2 hours; collect by centrifugation and vacuum dry to obtain acidified carbon Nanofibers. Weigh the acidified carbon nanofibers, and ultrasonically disperse them in methanol to obtain a methanol solution of carbon nanofibers with a concentration of 1mg / mL; configure 75mL of methanol solution of 70mM cobalt nitrate, and add to the methanol solution of carbon nanofibers under magnetic stirring The above solution was stirred for 1 hour; 50 mL of a methanol solution of 2-methylimidazole with a concentration of 300 mM was added under magnetic stirring conditions, and then reacted for 24 hours; the solid was collected by centrifugation, washed with methanol several times and then dried in vacuum to obtain carbon nanofibers @ZIF- 67. Put the above vacuum-dried carbon nan...

Embodiment 2

[0063] Example 2: Weigh 5g of carbon nanofibers, measure 1000mL of concentrated nitric acid and slowly add to the above solid, stir magnetically in a water bath at 85°C for 1 hour, and cool and stir at room temperature for 2 hours; collect by centrifugation and vacuum-dry to obtain acidified carbon nanofibers fiber. Weigh the carbon nanofibers after acidification, and ultrasonically disperse them in methanol to obtain a methanol solution of carbon nanofibers with a concentration of 2 mg / mL; 75 mL of a methanol solution of 100 mM cobalt nitrate is added to the methanol solution of carbon nanofibers under magnetic stirring. solution and stirred for 1 hour; under magnetic stirring conditions, add 50 mL of 2-methylimidazole methanol solution with a concentration of 200 mM, and react for 20 hours; collect samples by centrifugation, wash with methanol several times, and freeze-dry to obtain carbon nanofibers @ZIF-67 . The above freeze-dried carbon nanofibers @ZIF-67 were put into a...

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Abstract

The invention relates to the technical field of microwave absorbing materials and provides a composite microwave absorbing agent and a preparation method thereof. The composite microwave absorbing agent is in a porous structure, and carbon-containing Co / CoO nano frameworks are sequentially stringed on carbon nano fibers. The preparation method of the composite microwave absorbing agent includes: acidizing the carbon nano fibers, allowing adsorption of Co<2+> on surfaces of the acidized carbon nano fibers, coordinating with 2-methylimidazole, and pyrolyzing and carbonizing to obtain the composite microwave absorbing agent. Problems of unfavorable absorption performances and high pyrolysis temperature and energy consumption in a preparation process of composite microwave absorbing agents inthe prior art are solved. The prepared composite microwave absorbing agent in the porous framework structure has advantages of light weight, excellent absorption performances, technical simplicity andlow production cost.

Description

technical field [0001] The invention relates to the field of microwave absorbing materials, in particular to a composite microwave absorbing agent and a preparation method thereof. Background technique [0002] Carbon-based materials are excellent candidates for microwave absorbing materials due to their light weight and high dielectric constant. As a new type of carbon-based material, carbon nanofiber has the disadvantage of low absorption due to impedance mismatch when it is used alone as a microwave absorbing material due to its high dielectric constant. Therefore, carbon-based materials are combined with magnetic or other dielectric materials to reduce the dielectric constant, increase the magnetic permeability, and achieve impedance matching, thereby improving its microwave absorption performance. [0003] Chinese patent (ZL2013103383171) discloses a Co / C composite nanofiber microwave absorber prepared by electrospinning combined with post-stage heat treatment in one s...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): D06M11/83D06M11/49C09K3/00
CPCC09K3/00D06M11/49D06M11/83
Inventor 张惠陈红李士阔黄方志李坤振王磊
Owner 安徽璜峪电磁技术有限公司
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