Cicada slough biomass wave-absorbing material and preparation method thereof

Abstract

The invention belongs to the field of electromagnetic wave absorbing materials, and provides a cicada slough biomass wave-absorbing material and a preparation method thereof, cicada slough is carbonized by means of a one-step annealing method, and a light carbon-based ideal wave-absorbing material is prepared. An SEM spectrum shows that the surface of the carbonized cicada wing is provided with a nano-column array structure, and the special structure is easy for multiple reflection and scattering of electromagnetic waves, so that a large amount of electromagnetic waves are consumed. Meanwhile, the influences of different carbonization temperatures on the wave absorbing performance are compared, it is verified that the light carbon-based wave absorbing material prepared at the temperature of 650 DEG C has the excellent performance of being high in wave absorbing performance and large in absorption bandwidth, and within the testing frequency range of 2 GHz to 18 GHz, the minimum reflection loss is-47.83 dB, and the effective absorption bandwidth is 6.14 GHz.

Description

Technical Field

[0001] The invention belongs to the technical field of electromagnetic wave absorbing materials, and specifically relates to a cicada wing biomass absorbing material and a preparation method and application thereof. Background Art

[0002] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention, and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art.

[0003] With the widespread use of wireless communication equipment, while bringing convenience to life and production, it also causes serious electromagnetic wave pollution problems. How to effectively eliminate electromagnetic wave interference has become a hot topic in current research. Absorbing materials can convert incident electromagnetic wave energy into heat energy or other forms of energy, thereby effectively eliminating the interference caused by electromagnetic wave energy. However, existing electromagnetic wave absorbing materials such as soft ferromagnetic metals and alloys, multiphase composite materials, magnetic ferrites, conductive organic polymers, and conductive ceramics have problems such as high density, heavy weight, and waste materials that easily pollute the environment. Therefore, lightweight electromagnetic wave absorbing materials have become the focus of current research.

[0004] In existing research, Chinese patent CN 109626354 A discloses a biochar absorbing material based on grapefruit peel and its preparation method. The absorbing material is a mixture of natural grapefruit peel treated by vacuum calcination, organic adhesive and flame retardant, and the maximum reflection loss at 2mm is -44.5dB. Chinese patent CN 107722537A discloses a bio-based porous carbon absorbing composite material, which uses bamboo charcoal as biochar material, mixed with styrene-butadiene-styrene block copolymer SBS and polypropylene PP blend, ferrosoferric oxide, molybdenum disulfide, coupling agent and antioxidant, and the maximum reflection loss is -38dB. However, neither of them pays attention to the effective absorption bandwidth of the composite material, and it is difficult to be widely used in practice. Chinese patent CN 117776593 A discloses a method for preparing a biomass-based ultra-lightweight heat-insulating absorbing foam, which is prepared by mixing corn cobs carbonized at 800°C with bio-gum in an inert gas atmosphere, and has an effective absorption bandwidth of 5.6 GHz at 2.7 mm, but a maximum reflection loss of only -24.9 dB. Chinese patent CN 111574957 B discloses an absorbing material based on biological waste and magnetic material waste and a method for preparing the same, which is a composite material made by mixing biochar made from biological waste with magnetic refined powder made from magnetic material waste, and has a maximum reflection loss of -38.5 dB at 2.5 mm, and an effective absorption bandwidth of only 4.3 GHz, but the prepared composite material is heavy and easily oxidized, and has a narrow effective absorption bandwidth. Chinese patent CN 118439583 A discloses a biomass carbon-based composite material and its preparation method and application. After mixing and heating luffa, N,N-dimethylformamide and epichlorohydrin, ethylenediamine and triethylamine are added for step-by-step reaction to obtain a modified luffa, which is then immersed in a polyacid solution, dried and calcined at high temperature. The maximum reflection loss at 2.5 mm is only -27.3 dB, and the maximum effective absorption bandwidth is 4.34 GHz. The preparation process is complicated, and the use of acid-base solutions is easy to cause damage to the human body.

[0005] Therefore, it is difficult for existing biomass materials to combine the characteristics of light weight, low density, wide absorption band, and strong absorption, and the performance of biomass-based wave absorption still needs to be improved. Summary of the invention

[0006] The present invention aims to overcome the problems of heavy weight, high density, low absorption intensity, narrow effective bandwidth and complex preparation conditions of the above-mentioned biomass carbon-based absorbers, and provide a cicada wing biomass absorber with low raw material cost, simple preparation process, low target product density, light weight, thin thickness, wide bandwidth and strong absorption. The preparation method of the present invention can also be applied to the application research of other biomass carbon source materials similar to cicada wings, and has broad application prospects.

[0007] In order to achieve the above object, the present invention adopts the following technical solution:

[0008] The first aspect of the present invention provides a cicada wing biomass absorbing material, comprising:

[0009] Carbonized cicada wing lamellae;

[0010] The surface of the carbonized cicada wing layer is loaded with a nano-column array structure.

[0011] The study found that cicada wings with microscopic nano-column structures are a natural lightweight bio-carbon source. Their carbides present an array of nano-column structures, which can achieve multiple reflections and scattering of electromagnetic waves, thereby consuming electromagnetic waves. Therefore, they can be used as potential absorbing materials.

[0012] In some embodiments, the nanorod structure has a height of 180-260 nm, a diameter of 70-90 nm, and a spacing of 150-200 nm.

[0013] In some embodiments, the carbonized cicada wing layer has a thickness of 1 to 2 μm.

[0014] In some embodiments, the cicada wing biomass absorbing material is 2-3 mm, preferably, 2.50 mm.

[0015] The second aspect of the present invention provides a method for preparing a cicada wing biomass absorbing material, comprising:

[0016] Under the protection of an inert atmosphere, the cicada wing is carbonized to obtain a carbonized cicada wing layer;

[0017] The carbonized cicada wing sheet is ground and black powder is collected to obtain the cicada wing biomass absorbing material.

[0018] The present invention develops a new biomass carbon-based absorbing material with light weight, low density, wide absorption frequency band, strong absorption and simple preparation, which has potential value in solving electromagnetic interference and achieving radar stealth effect.

[0019] In some embodiments, the cicada wings are selected from one or both of black cicada and cold cicada.

[0020] In some embodiments, the cicada wings are pretreated, including: washing and drying the cicada wings.

[0021] In some embodiments, the carbonization conditions include: a carbonization temperature of 550 to 750° C., a heating time of 120 to 140 minutes, a carbonization time of 1 to 2 hours, and a cooling time of 3 to 5 hours.

[0022] In some embodiments, the heating rate is 3 to 8°C / min;

[0023] In some embodiments, the inert atmosphere is nitrogen;

[0024] In some embodiments, the grinding time is 10 to 20 minutes.

[0025] The third aspect of the present invention provides the use of the above-mentioned cicada wing biomass absorbing material in the preparation of electromagnetic wave absorbing materials or absorbing devices.

[0026] Beneficial Effects of the Invention

[0027] (1) The cicada wing biomass absorbing material provided by the present invention is processed by simple mechanical grinding and one-step annealing method, and the preparation process is simple. In addition, the prepared absorbing material has excellent microwave absorption performance and has the characteristics of light weight, low density, wide absorption frequency band, strong absorption, and simple preparation.

[0028] (2) The cicada wing biomass absorbing material provided by the present invention retains the natural nanocolumn array structure of cicada wings, so that it has excellent electromagnetic wave absorption performance while also having a certain degree of hydrophobicity and high temperature resistance of 200°C.

[0029] (3) The cicada wing biomass absorbing material provided by the present invention adjusts the electromagnetic parameters by changing the carbonization temperature, and further adjusts the electromagnetic wave absorption performance. The cicada wing biomass absorbing material carbonized at 650°C provided by the present invention has a reflection loss of up to -47.83 dB at 14.13 GHz when the thickness is 2.5 mm, and the effective absorption bandwidth (reflection loss is less than -10 dB) is up to 6.14 GHz, covering 11.08 to 17.08 GHz.

[0030] (4) The cicada wing biomass absorbing material provided by the present invention, wherein the biochar is made from cicada wings as raw materials and is calcined under nitrogen protection. The raw materials are easily available and the preparation process is simple. At present, cicada wings are mainly processed by incineration or landfill, which not only brings serious environmental pollution but also causes waste of resources. In the present invention, cicada wings are used as raw materials and are made into biochar absorbing materials through calcination under nitrogen protection. Waste recycling can be achieved and the preparation process does not involve the use of acidic and alkaline chemicals, thereby ensuring the safety of the experimental process and environmental sustainability. Experimental studies have found that the cicada wing-based biomass absorbing material provided by the present invention has excellent electromagnetic wave absorption effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention, and the exemplary embodiments of the present invention and their description are used to explain the present invention and do not constitute improper limitations on the present invention.

[0032] Figure 1 are microscopic morphology images of the absorbing materials of Example 1 (a), Example 2 (b) and Example 3 (c) of the present invention;

[0033] Figure 2 It is a curve diagram showing the variation of the relative complex dielectric constant of the absorbing materials of Example 1, Example 2 and Example 3 of the present invention with the frequency in the 2-18 GHz frequency band.

[0034] Figure 3 It is a curve diagram showing the variation of relative complex magnetic permeability of the absorbing materials of Example 1, Example 2 and Example 3 of the present invention with frequency in the 2-18 GHz frequency band.

[0035] Figure 4 It is a reflectivity curve diagram of the absorbing materials prepared by Example 1, Example 2 and Example 3 of the present invention in the 2-18 GHz frequency band.

[0036] Figure 5 It is a reflectivity curve diagram of the absorbing material prepared by Example 2 of the present invention in the 2-18 GHz frequency band.

[0037] Figure 6 It is a reflectivity curve diagram of the absorbing material prepared by Example 3 of the present invention in the 2-18 GHz frequency band.

[0038] Figure 7 It is a reflectivity curve diagram of the absorbing material prepared by using Example 1, Example 2 and Example 3 of the present invention at 2.5 mm. DETAILED DESCRIPTION

[0039] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0040] The present invention will be further described in detail below in conjunction with specific embodiments. It should be noted that the specific embodiments are intended to explain the present invention rather than to limit it.

[0041] Example 1

[0042] The cicada wing biomass absorbing material provided by the embodiment of the present invention has a biomass carbon-based sheet structure with a nano-pillar array, and the microscopic morphology is as follows: Figure 1 shown.

[0043] The method for preparing the cicada wing biomass absorbing material provided in the embodiment of the present invention comprises the following steps:

[0044] (1) Wash the surface of the cicada wing with deionized water and anhydrous ethanol for 5 to 10 minutes, and dry it in a forced air drying oven to obtain a dry cicada wing layer.

[0045] (2) Place the cicada wing layer obtained in step (1) into a porcelain boat with a specification of 5x8 cm.

[0046] (3) The porcelain boat was placed in a tube furnace and heated for 125 min under a nitrogen atmosphere. The temperature was raised to 650°C, maintained for 60 min, and cooled for 3 h to obtain black carbonized cicada wing sheets.

[0047] (4) The obtained black cicada wing flakes were ground in a mortar for 10 min, and the black powder was collected to obtain the cicada wing biomass absorbing material. The microscopic morphology is shown in the figure below. Figure 1 As shown in (a).

[0048] Specifically, the cicada wing biomass absorbing material prepared in Example 1 of the present invention and paraffin were ultrasonically uniformly mixed in a mass ratio of absorbing material: paraffin = 1:1, filled into a mold, and pressed into a cylindrical ring test sample. The absorbing performance of the cylindrical ring test sample was tested using an Agilent E5071C vector network analyzer in the United States. The test frequency range was 2-18 GHz. The curve of the relative complex dielectric constant of the absorbing material in the 2-18 GHz frequency band versus frequency is shown in FIG. Figure 2 As shown in the figure, the curve of the relative complex permeability of the absorbing material in the 2-18 GHz frequency band changes with frequency is as follows Figure 3 As shown, the reflectivity curve of the absorbing material in the 2-18GHz frequency band is as follows Figure 4 As shown, the reflectivity curve of the absorbing material at 2.5mm in the 2-18GHz frequency band is as follows Figure 7 shown. Figure 4 The reflection loss diagram for the thickness of 1.0 to 5.0 mm obtained for implementation case 1 shows that when the thickness is 2.5 mm, there is a reflection loss of up to -47.83 dB at 14.13 GHz, and the effective absorption bandwidth (reflection loss less than -10 dB) is as high as 6.14 GHz, covering 11.08 to 17.08 GHz, that is, there is a wider effective absorption frequency.

[0049] Embodiment 2:

[0050] The cicada wing biomass absorbing material and preparation method provided in this embodiment are basically the same as those in Example 1, except that the carbonization temperature is 750° C. and the heating time is 155 min.

[0051] The method for preparing the cicada wing biomass absorbing material provided in the embodiment of the present invention comprises the following steps:

[0052] (1) Wash the surface of the cicada wing with deionized water and anhydrous ethanol for 5 to 10 minutes, and dry it in a forced air drying oven to obtain a dry cicada wing layer.

[0053] (2) Place the cicada wing layer obtained in step (1) into a porcelain boat with a specification of 5x8 cm.

[0054] (3) The porcelain boat was placed in a tube furnace and heated for 155 min under a nitrogen atmosphere. The temperature was raised to 750°C, maintained for 60 min, and cooled for 3 h to obtain black carbonized cicada wing sheets.

[0055] (4) The obtained black cicada wing flakes were ground in a mortar for 10 min, and the black powder was collected to obtain the cicada wing biomass absorbing material. The microscopic morphology is shown in the figure below. Figure 1 As shown in (b).

[0056] Specifically, the cicada wing biomass absorbing material prepared in Example 1 of the present invention and paraffin wax are heated and melt-mixed (mechanically mixed) according to a mass ratio of absorbing material: paraffin wax = 1:1 until uniformly mixed, dispersed until no obvious aggregation is observed, filled into a clean mold, and pressed into a cylindrical ring test sample. The absorbing performance of the cylindrical ring test sample is detected using an Agilent E5071C vector network analyzer in the United States, and the test frequency range is 2-18 GHz. The curve of the relative complex dielectric constant of the absorbing material in the 2-18 GHz frequency band as a function of frequency is shown in FIG. Figure 2 As shown in the figure, the curve of the relative complex permeability of the absorbing material in the 2-18 GHz frequency band changes with frequency is as follows Figure 3 As shown, the reflectivity curve of the absorbing material in the 2-18GHz frequency band is as follows Figure 4 As shown, the reflectivity curve of the absorbing material at 2.5mm in the 2-18GHz frequency band is as follows Figure 7 shown. Figure 5 The reflection loss diagram for the implementation case 2 at a thickness of 1.0 to 5.0 mm shows a reflection loss of up to -66.61 dB at 4.49 GHz, and an effective absorption bandwidth (reflection loss less than -10 dB) of up to 3.18 GHz, covering 14.73 to 17.91 GHz, that is, a relatively wide effective absorption frequency.

[0057] Embodiment 3:

[0058] The cicada wing biomass absorbing material and preparation method provided in this embodiment are basically the same as those in Example 1, except that the carbonization temperature is 550° C. and the heating time is 105 min.

[0059] The method for preparing the cicada wing biomass absorbing material provided in the embodiment of the present invention comprises the following steps:

[0060] (1) Wash the surface of the cicada wing with deionized water and anhydrous ethanol for 5 to 10 minutes, and dry it in a forced air drying oven to obtain a dry cicada wing layer.

[0061] (2) Place the cicada wing layer obtained in step (1) into a porcelain boat with a specification of 5x8 cm.

[0062] (3) The porcelain boat was placed in a tube furnace and heated for 105 min under a nitrogen atmosphere. The temperature was raised to 550°C, maintained for 60 min, and cooled for 3 h to obtain black carbonized cicada wing sheets.

[0063] (4) The obtained black cicada wing flakes were ground in a mortar for 10 min, and the black powder was collected to obtain the cicada wing biomass absorbing material. The microscopic morphology is shown in the figure below. Figure 1 As shown in (c).

[0064] Specifically, the cicada wing biomass absorbing material prepared in Example 3 of the present invention and paraffin wax are heated and melt-mixed (mechanically mixed) in a mass ratio of absorbing material: paraffin wax = 1:1 until uniformly mixed and dispersed until no obvious aggregation is observed, and then filled into a clean mold and pressed into a cylindrical ring test sample. The absorbing performance of the cylindrical ring test sample is tested using a vector network analyzer of Agilent E5071C in the United States. The test frequency range is 2-18 GHz. The curve of the relative complex dielectric constant of the absorbing material in the 2-18 GHz frequency band as a function of frequency is shown in FIG. Figure 2 As shown in the figure, the curve of the relative complex permeability of the absorbing material in the 2-18 GHz frequency band changes with frequency is as follows Figure 3 As shown, the reflectivity curve of the absorbing material in the 2-18GHz frequency band is as follows Figure 4 As shown, the reflectivity curve of the absorbing material at 2.5mm in the 2-18GHz frequency band is as follows Figure 7 shown. Figure 6 The reflection loss diagram for the thickness of 1.0 to 5.0 mm obtained for implementation case 3 shows that when the thickness of the absorbing material is 5.0 mm, the reflection loss at ~5.0 mm is only -5.5 dB, and the effective absorption bandwidth is 0 GHz.

[0065] Comparative Example 1

[0066] The difference from Example 1 is that dragonfly wings are used instead of cicada wings. The wave absorption performance is as follows: when the thickness is 2.5 mm, a reflection loss of -38.2 dB is obtained at 15.21 GHz, and the effective absorption bandwidth is 4.21 GHz, covering 13.41 to 17.62 GHz.

[0067] Comparative Example 2

[0068] The difference from Example 1 is that butterfly wings are used instead of cicada wings. The wave absorption performance is as follows: when the thickness is 2.1 mm, a reflection loss of -36.5 dB is obtained at 16.01 GHz, and the effective absorption bandwidth is 3.81 GHz, covering 14.05 to 17.86 GHz.

[0069] From the comparison between Example 1 and Comparative Examples 1 and 2, it can be seen that compared with biomass materials such as dragonfly wings and butterfly wings, the absorbing material prepared using cicada wings has better reflection loss and effective absorption bandwidth.

[0070] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A cicada wing biomass absorbing material, characterized in that: include: Carbonized cicada wing lamellae; The surface of the carbonized cicada wing layer is loaded with a nano-column array structure.

2. The cicada wing biomass absorbing material according to claim 1, characterized in that: The height of the nanocolumn structure is 180-260 nm, the diameter is 70-90 nm, and the spacing is 150-200 nm.

3. The cicada wing biomass absorbing material according to claim 1, characterized in that: The thickness of the carbonized cicada wing layer is 1 to 2 μm.

4. The cicada wing biomass absorbing material according to claim 1, characterized in that: The cicada wing biomass absorbing material is 2-3mm, or 2.50mm.

5. A method for preparing a cicada wing biomass absorbing material, characterized in that: include: Under the protection of an inert atmosphere, the cicada wing is carbonized to obtain a carbonized cicada wing layer; The carbonized cicada wing sheet is ground and black powder is collected to obtain the cicada wing biomass absorbing material.

6. The method for preparing the cicada wing biomass absorbing material according to claim 5, characterized in that: The cicada wings are selected from one or both of black cicada and cold cicada.

7. The method for preparing the cicada wing biomass absorbing material according to claim 5, characterized in that: The cicada wings are pre-treated, including: cleaning and drying the cicada wings.

8. The method for preparing the cicada wing biomass absorbing material according to claim 5, characterized in that: The carbonization conditions include: a carbonization temperature of 550 to 750° C., a heating time of 120 to 140 minutes, a carbonization time of 1 to 2 hours, and a cooling time of 3 to 5 hours.

9. The method for preparing the cicada wing biomass absorbing material according to claim 5, characterized in that: The heating rate is 3-8°C / min; Or, the inert atmosphere is nitrogen; Or, the grinding time is 10 to 20 minutes.

10. Use of the cicada wing biomass absorbing material according to any one of claims 1 to 4 in the preparation of electromagnetic wave absorbing materials or absorbing devices.

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