Preparation method of polymer-converted ceramic-based microwave absorbing material supported in situ with nitrogen-doped graphene

A nitrogen-doped graphene and wave-absorbing material technology, applied in the field of wave-absorbing materials, can solve problems such as easy structure agglomeration, insufficient wave-absorbing performance, cumbersome preparation methods, etc., and achieve improved electron transfer ability, high output, and simple process Effect

Active Publication Date: 2022-07-05
NORTHWESTERN POLYTECHNICAL UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] In order to avoid the deficiencies of the prior art, the present invention proposes a method for preparing a polymer-converted ceramic-based wave-absorbing material that supports nitrogen-doped graphene in situ, which solves the tedious and easy preparation method of the existing graphene-doped PDCs material. Insufficient microwave absorption performance caused by structural agglomeration

Method used

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  • Preparation method of polymer-converted ceramic-based microwave absorbing material supported in situ with nitrogen-doped graphene
  • Preparation method of polymer-converted ceramic-based microwave absorbing material supported in situ with nitrogen-doped graphene
  • Preparation method of polymer-converted ceramic-based microwave absorbing material supported in situ with nitrogen-doped graphene

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Effect test

Embodiment 1

[0032] (1) First disperse 6g of urea into 15ml of xylene solution, then transfer it to Schlenk device, add 6.6ml of liquid polysilazane, stir and react at 80°C for 2h, and then remove organic matter under vacuum Solvent, single source precursor can be obtained;

[0033] (2) Put the obtained single-source precursor into a tube furnace, use nitrogen as a protective gas, and raise the furnace temperature to 300°C at a heating rate of 5°C / min, so that the precursor is fully cross-linked and cured at this temperature. 2h, after the heat preservation is completed, turn off the heating power and naturally cool down with the furnace. The solidified powder is fully ground and sieved to obtain a 200-mesh precursor powder;

[0034] (3) put the sieved precursor powder into a graphite crucible, then put the crucible into a high-temperature tube furnace, use nitrogen as a protective gas, and raise the furnace temperature to 900 ℃ with a heating rate of 5 ℃ / min, The precursor was cracked a...

Embodiment 2

[0036] (1) Disperse 3g of melamine into 15ml of xylene solution, transfer it to the Schlenk device, add 6ml of liquid polysilicon, stir and react at 80°C for 2h, and then remove the organic solvent under vacuum , the single-source precursor can be obtained;

[0037] (2) Put the obtained single-source precursor into a tube furnace, use nitrogen as a protective gas, and raise the furnace temperature to 180°C at a heating rate of 5°C / min, so that the precursor is fully cross-linked and cured at this temperature. 5h, after the heat preservation is completed, turn off the heating power and naturally cool down with the furnace. The solidified powder is fully ground and sieved to obtain a 300-mesh precursor powder;

[0038] (3) put the sieved precursor powder into a graphite crucible, then put the crucible into a high temperature tube furnace, use nitrogen as a protective gas, and raise the furnace temperature to 1000 ℃ at a heating rate of 5 ℃ / min, The precursor was cracked at this ...

Embodiment 3

[0040] (1) Disperse 10g of N,N'-methylenebisacrylamide into 30ml of xylene solution, transfer it to Schlenk device, add 5ml of liquid polysilazane, and stir the reaction at 100°C 3h, and then remove the organic solvent under vacuum to obtain a single-source precursor;

[0041] (2) Put the obtained single-source precursor into a tube furnace, use nitrogen as a protective gas, and raise the furnace temperature to 220°C at a heating rate of 5°C / min, so that the precursor is fully cross-linked and cured at this temperature. 2h, after the heat preservation is completed, turn off the heating power and naturally cool down with the furnace. The solidified powder is fully ground and sieved to obtain a 300-mesh precursor powder;

[0042] (3) put the sieved precursor powder into a graphite crucible, then put the crucible into a high temperature tube furnace, use nitrogen as a protective gas, and raise the furnace temperature to 1100 ℃ at a heating rate of 8 ℃ / min, The precursor was cra...

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Abstract

The invention relates to a method for preparing a polymer-converted ceramic-based wave absorbing material that supports nitrogen-doped graphene in-situ. An organic nitrogen source is reacted with a silicon-based polymer to generate a single-source precursor, and the precursor is made by cracking and high-temperature heat treatment. Self-assembly to generate in-situ supported nitrogen-doped graphene-based ceramic-based absorbers. In the invention, a single-source precursor is synthesized in one step by an organic chemical modification method, and pyrolyzed at a high temperature to obtain a nitrogen-doped graphene-loaded polymer conversion ceramics (NG-PDCs) matrix composite material with excellent wave absorption performance. The multiphase ceramics loaded with nitrogen-doped graphene were transformed from synthesized single-source precursors, in which nitrogen-doped graphene was uniformly distributed in the polymer-converted ceramics. The chemical combination is used to introduce NG with better absorbing properties in one step, in order to overcome the disadvantages of complicated preparation and easy structure agglomeration of traditional methods plus graphene, and improve the absorbing properties of PDCs materials.

Description

technical field [0001] The invention belongs to the technical field of wave-absorbing materials, and relates to a preparation method of a polymer-converted ceramic-based wave-absorbing material that supports nitrogen-doped graphene in-situ. Background technique [0002] Polymer derived ceramics (PDCs) technology has the characteristics of strong artificial design of ceramic precursor molecules, controllable domain size of pyrolytic ceramics, and the ability to obtain amorphous / nanocrystalline in-situ composite structures. It is widely used in the preparation of composite materials. Silicon-based PDCs (such as SiCN, SiOC, and SiBCN, etc.) exhibit excellent high-temperature stability, oxidation resistance and creep resistance. On this basis, further high-temperature heat treatment can enable the formation of SiC nanocrystals and free C inside the ceramics. The network structure increases the dielectric constant and electrical conductivity of composite materials, and has broad...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C04B35/589C04B35/596C04B35/571C04B35/577C04B35/563C04B35/622
CPCC04B35/589C04B35/571C04B35/5603C04B35/563C04B35/622C04B2235/425C04B2235/6562C04B2235/6567C04B2235/96Y02E60/50
Inventor 付前刚张育育孙佳闫宁宁韩旭
Owner NORTHWESTERN POLYTECHNICAL UNIV
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