CN113023723A - Electromagnetic wave-absorbing material prepared from shaddock peel and preparation method thereof - Google Patents
Electromagnetic wave-absorbing material prepared from shaddock peel and preparation method thereof Download PDFInfo
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- CN113023723A CN113023723A CN202110153806.4A CN202110153806A CN113023723A CN 113023723 A CN113023723 A CN 113023723A CN 202110153806 A CN202110153806 A CN 202110153806A CN 113023723 A CN113023723 A CN 113023723A
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- 235000001759 Citrus maxima Nutrition 0.000 title claims abstract description 31
- 244000276331 Citrus maxima Species 0.000 title claims abstract description 31
- 239000011358 absorbing material Substances 0.000 title claims abstract description 30
- 238000002360 preparation method Methods 0.000 title claims abstract description 11
- 239000003575 carbonaceous material Substances 0.000 claims abstract description 28
- 238000000034 method Methods 0.000 claims abstract description 24
- 230000008569 process Effects 0.000 claims abstract description 11
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 10
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 10
- 238000004108 freeze drying Methods 0.000 claims description 13
- 238000001354 calcination Methods 0.000 claims description 11
- 239000002243 precursor Substances 0.000 claims description 10
- 238000010438 heat treatment Methods 0.000 claims description 5
- 238000000137 annealing Methods 0.000 claims description 3
- 238000001035 drying Methods 0.000 claims description 3
- 238000007710 freezing Methods 0.000 claims description 3
- 230000008014 freezing Effects 0.000 claims description 3
- 239000012298 atmosphere Substances 0.000 claims description 2
- 239000011148 porous material Substances 0.000 claims 1
- 239000000463 material Substances 0.000 abstract description 13
- 238000010521 absorption reaction Methods 0.000 abstract description 7
- 238000009413 insulation Methods 0.000 abstract description 5
- 238000010923 batch production Methods 0.000 abstract description 2
- 239000003153 chemical reaction reagent Substances 0.000 abstract description 2
- 239000004964 aerogel Substances 0.000 description 3
- 238000001931 thermography Methods 0.000 description 3
- 238000001069 Raman spectroscopy Methods 0.000 description 2
- 238000002441 X-ray diffraction Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000002028 Biomass Substances 0.000 description 1
- 241000282414 Homo sapiens Species 0.000 description 1
- 239000012300 argon atmosphere Substances 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 239000008367 deionised water Substances 0.000 description 1
- 229910021641 deionized water Inorganic materials 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000011049 filling Methods 0.000 description 1
- 238000005087 graphitization Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 239000011810 insulating material Substances 0.000 description 1
- 230000005012 migration Effects 0.000 description 1
- 238000013508 migration Methods 0.000 description 1
- 239000002086 nanomaterial Substances 0.000 description 1
- 239000012188 paraffin wax Substances 0.000 description 1
- 230000010287 polarization Effects 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B32/00—Carbon; Compounds thereof
- C01B32/20—Graphite
- C01B32/205—Preparation
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- Organic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Inorganic Chemistry (AREA)
- Shielding Devices Or Components To Electric Or Magnetic Fields (AREA)
Abstract
The invention discloses an electromagnetic wave absorbing material prepared from shaddock peel, wherein a three-dimensional communicated hole structure is arranged in the electromagnetic wave absorbing material, a skeleton of the electromagnetic wave absorbing material is a graphitized carbon-based skeleton, and the carbon-based skeleton is also provided with a mesoporous structure. The invention also discloses a preparation method of the electromagnetic wave-absorbing material. The electromagnetic wave-absorbing material prepared from the shaddock peel has a three-dimensional network porous structure macroscopically and a mesoporous structure microscopically, so that the weight of the material is reduced, and the heat insulation capability of the material is improved; meanwhile, the graphitized carbon-based material has good conductivity, so that the graphitized carbon-based material has good dielectric loss capability, can enhance the absorption loss of electromagnetic waves, and further effectively improves the absorption and attenuation capabilities of the carbon-based material on the electromagnetic waves; the carbon-based material prepared by the method has the advantages of low density, large specific surface area and good dielectric loss, and the preparation method has simple process, does not need any chemical reagent, has low cost and can realize large-scale and large-batch production.
Description
Technical Field
The invention relates to an electromagnetic wave-absorbing material prepared from shaddock peel and a preparation method of the electromagnetic wave-absorbing material.
Background
The problems of electromagnetic wave pollution caused by the rapid development of modern communication, broadcasting, television, navigation, remote sensing and remote measuring, industrial automation, household appliances, geological exploration, power systems, medical electronic equipment and the like are continuously aggravated, so that the problem of reducing electromagnetic interference is not easy. Electromagnetic shielding and wave absorbing materials are used as key materials for protecting human beings and precision equipment, and not only occupy important strategic positions in the military field, but also attract wide attention in the civil field. In consideration of the severity of the electromagnetic microwave pollution problem and the complexity of the material application environment, it is urgent to integrate multiple functions into one material. The electromagnetic wave-absorbing material with multiple functions has great attraction to the next generation of wireless technology and portable electronic equipment.
Disclosure of Invention
The purpose of the invention is as follows: aiming at the problem of application environment complexity of the electromagnetic wave-absorbing material in the prior art, the invention provides the electromagnetic wave-absorbing material prepared from shaddock peel, and the material not only has electromagnetic wave-absorbing performance, but also has heat insulation and infrared stealth functions; the invention also provides a preparation method of the electromagnetic wave-absorbing material prepared from the shaddock peel, and the carbon-based material with the intrinsic complete three-dimensional network structure of the shaddock peel can be prepared by the method.
The technical scheme is as follows: according to the electromagnetic wave absorbing material prepared from the shaddock peel, a three-dimensional communicated hole structure is arranged in the electromagnetic wave absorbing material, a skeleton of the electromagnetic wave absorbing material is a graphitized carbon-based skeleton, and the carbon-based skeleton is also provided with a mesoporous structure.
The preparation method of the electromagnetic wave-absorbing material prepared from the shaddock peel comprises the following specific steps: putting the peeled shaddock peel into a freeze dryer for freeze drying treatment to obtain a precursor; and then placing the precursor subjected to freeze drying treatment in an inert atmosphere for high-temperature annealing and calcination to obtain the electromagnetic wave-absorbing material derived from the shaddock peel. The original micro-nano structure of the biomass can be kept from being damaged by the freeze-dried precursor under high-temperature treatment.
Wherein in the step (1), the peeling time of the shaddock peel is not more than 10 minutes.
Wherein in the step (1), the pre-freezing time is not less than 6h in the freeze drying process.
Wherein, in the step (1), the drying time is not less than 48h in the freeze drying process.
Wherein, in the step (1), the vacuum degree is at least 0.001Pa in the freeze drying process.
Wherein, in the step (2), in the calcining process, the calcining temperature is not lower than 800 ℃, the heating rate is not lower than 2 ℃/min, and the calcining time is not lower than 2 h; and calcining to obtain the carbon-based material in the aerogel structure, wherein the carbon-based material has dielectric loss capacity. The precursor after freeze drying treatment can realize that the carbon-based skeleton with a three-dimensional porous network structure does not have microstructure fracture and macroscopic porous structure collapse under high-temperature treatment.
Has the advantages that: the electromagnetic wave-absorbing material prepared from the shaddock peel has a three-dimensional network porous structure macroscopically and a large number of mesoporous structures microscopically, so that the weight of the material is reduced, and the heat insulation capability of the material is improved; meanwhile, the graphitized carbon-based material has good conductivity, so that the graphitized carbon-based material has good dielectric loss capability, can enhance the absorption loss of electromagnetic waves, and further effectively improves the absorption and attenuation capabilities of the carbon-based material on the electromagnetic waves; the carbon-based material prepared by the method has the advantages of low density, large specific surface area and good dielectric loss, and the preparation method has simple process, does not need any chemical reagent, has low cost and can realize large-scale and large-batch production.
Drawings
FIG. 1 is an X-ray diffraction pattern of the carbon-based material prepared in example 1;
FIG. 2 is a Raman diagram of the carbon-based material prepared in example 1;
FIG. 3 is an SEM photograph of the precursor prepared in example 1;
fig. 4 is an SEM photograph of the carbon-based material prepared in example 1;
FIG. 5 is an infrared thermal imaging of the carbon-based material prepared in example 1;
fig. 6 is a graph of reflection loss of the carbon-based material prepared in example 1.
Detailed Description
The technical solution of the present invention is further explained with reference to the accompanying drawings and specific embodiments.
Example 1
The invention relates to a preparation method of an electromagnetic wave-absorbing material prepared from shaddock peel, which specifically comprises the following steps:
(1) cleaning the entire shaddock peel with deionized water, and slightly wiping the shaddock peel with a chipless paper towel to remove the shaddock peel; then putting the fresh shaddock peel stripped for no more than 10 minutes into a freeze dryer, and carrying out freeze drying treatment according to the set pre-freezing time of 6 hours and the drying time of 48 hours to ensure that the vacuum degree is 0.001Pa in the freeze drying process, and finally obtaining a precursor product derived from the fresh shaddock peel, and recording the precursor product as P800;
and 2, placing the product obtained in the step 1 in an argon atmosphere for high-temperature annealing and calcining, heating to 800 ℃ according to the heating rate of 2 ℃/min, and preserving the heat for 2 hours to obtain the carbon-based material with the aerogel structure, wherein the carbon-based material is marked as G800.
Fig. 1 is an X-ray diffraction pattern of the carbon-based material obtained in example 1, and as can be seen from fig. 1, diffraction peaks of the product obtained in example 1 at 24.5 ° and 43.4 ° carbons are very apparent, respectively representing the (002) plane and the (100) plane of graphitized carbon.
FIG. 2 is a Raman diagram of the carbon-based material prepared in example 1, and it can be seen from FIG. 2 that I of the product prepared in example 1D/IGA value of 1.00 indicates that the carbon-based material has a certain degree of graphitization.
Fig. 3 is an SEM photograph of the precursor P800 prepared in example 1, and it can be seen from fig. 3 that the uncalcined sample, which has a three-dimensional network porous structure, maintains the intrinsic structural characteristics of the shaddock peel and contributes to the improvement of its lightweight characteristics.
Fig. 4 is an SEM photograph of the carbon-based material G800 prepared in example 1, and it can be seen from fig. 4 that after calcination at 800 ℃, the three-dimensional porous network structure of the sample shrinks to some extent in size, and some mesoporous structures are generated on the network nodes and the surface of the carbon-based skeleton, so that the surface of the sample becomes significantly rougher, which is beneficial to further improving the light weight property and the thermal insulation property of the material, and providing more polarization relaxation spaces to facilitate electromagnetic loss.
Fig. 5 is an ir thermography of the carbon-based material G800 prepared in example 1, and it can be seen from fig. 5 that the ir thermography of the sample was taken at 3min when the heating stage temperature was set to 70 ℃, and the detected temperatures of the carbon-based material G800 were 35.3 ℃, respectively, which are similar to the ambient cold environment temperature, indicating that it has not only good heat insulating properties but also excellent thermal ir stealth properties, indicating that the prepared carbon-based material G800 can be used for the preparation of heat insulating materials and thermal ir stealth materials in practical applications.
Fig. 6 is a graph of the reflection loss of the carbon-based material G800 prepared in example 1, and the reflection loss curve is continuously shifted to a low frequency as the thickness increases due to the dispersion effect. When the filling ratio of the sample to the paraffin is 1:4, the aerogel G800 shows excellent electromagnetic wave absorbing performance within the range of 2-18 GHz, when the matching thickness is 1.7mm, the reflection loss is-14.88 dB, and the maximum effective absorption frequency bandwidth can reach 5.80 GHz; when the matching thickness is 2.3mm, the effective absorption bandwidth is 2.44GHz, and the maximum reflection loss can reach-29.50 dB.
The carbon-based material disclosed by the invention has a plurality of mesoporous structures on the microcosmic aspect and has a three-dimensional communicated network structure on the macroscopic aspect, the structure effectively provides a transmission path for electron transition and migration, and graphitized carbon can improve the conductivity of the material, so that the absorption and loss of electromagnetic waves are realized; meanwhile, the porous structure is beneficial to the exertion of the heat insulation performance of the material and the exhibition of the thermal infrared stealth performance of the material.
Claims (7)
1. An electromagnetic wave absorbing material prepared from shaddock peel is characterized in that: the electromagnetic wave-absorbing material is internally provided with a three-dimensional conductive pore structure, the skeleton of the electromagnetic wave-absorbing material is a graphitized carbon-based skeleton, and the carbon-based skeleton is also provided with a mesoporous structure.
2. The preparation method of the electromagnetic wave absorbing material prepared from the shaddock peel, according to claim 1, is characterized by comprising the following steps: putting the peeled shaddock peel into a freeze dryer for freeze drying treatment to obtain a precursor; and then placing the precursor subjected to freeze drying treatment in an inert atmosphere for high-temperature annealing and calcination to obtain the carbon-based material derived from the shaddock peel.
3. The method for preparing the electromagnetic wave absorbing material prepared from the shaddock peel according to claim 2, wherein the method comprises the following steps: in the step (1), the peeling time of the shaddock peel is not more than 10 minutes.
4. The method for preparing the electromagnetic wave absorbing material prepared from the shaddock peel according to claim 2, wherein the method comprises the following steps: in the step (1), the pre-freezing time is not less than 6h in the freeze drying process.
5. The method for preparing the electromagnetic wave absorbing material prepared from the shaddock peel according to claim 2, wherein the method comprises the following steps: in the step (1), the drying time is not less than 48h in the freeze drying process.
6. The method for preparing the electromagnetic wave absorbing material prepared from the shaddock peel according to claim 2, wherein the method comprises the following steps: in the step (1), the vacuum degree is at least 0.001Pa in the freeze drying process.
7. The method for preparing the electromagnetic wave absorbing material prepared from the shaddock peel according to claim 2, wherein the method comprises the following steps: in the step (2), in the calcining process, the calcining temperature is not lower than 800 ℃, the heating rate is not lower than 2 ℃/min, and the calcining time is not lower than 2 h.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114656281A (en) * | 2022-04-24 | 2022-06-24 | 南京航空航天大学 | Preparation method of carbonized cotton cellulose aerogel electromagnetic wave-absorbing material |
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