CN114958301B - Carbon nano tube/Ni porphyrin loaded wave-absorbing material, preparation method and application thereof - Google Patents

Abstract

The invention belongs to the field of wave-absorbing materials, and in particular relates to a carbon nanotube/Ni porphyrin-loaded wave-absorbing material and a preparation method and application thereof. The carbon nanotube/Ni porphyrin-loaded absorbing material is a one-dimensional tubular interwoven three-dimensional network structure, and the fiber is composed of a CNTs matrix and a Ni-TAPP loaded thin layer, wherein the Ni-TAPP loaded thin layer The layers are distributed on the surface of the CNTs matrix. The method includes: (1) mixing Ni-TAPP and DMF solution, CNTs and DMF solution and then standing still; (2) performing centrifugation, washing and drying the reactants after standing to obtain the final product. In the invention, Ni-TAPP and CNTs are effectively composited at the nanometer scale, and the prepared material has excellent performance.

Description

Carbon nanotube/Ni porphyrin loaded microwave absorbing material and its preparation method and application

technical field

The invention belongs to the field of wave-absorbing materials, in particular to a carbon nanotube/Ni porphyrin-loaded wave-absorbing material and its preparation method and application.

Background technique

The information disclosed in the Background of the Invention is only intended to increase the understanding of the general background of the invention, and is not necessarily to be taken as an acknowledgment or any form of suggestion that the information constitutes the prior art that is already known to those skilled in the art.

In recent years, lightweight and high-performance carbon nanotubes (CNTs) have attracted extensive attention due to their unique advantages over traditional metallic electromagnetic wave absorbing materials. However, the excessively high dielectric constant of carbon nanotubes leads to poor impedance matching between carbon materials and air, thus resulting in poor electromagnetic wave absorption performance. To overcome this obstacle, the common idea is to load Fe, Co, Ni, etc. magnetic particles. However, the density of loaded particles is much higher than that of CNTs without exception, resulting in high density composites. In addition, the complex preparation process and easy oxidation also limit its further application. Therefore, it is still a major challenge to explore light-weight, highly chemically stable and highly efficient carbon nanotube-based electromagnetic wave absorbing materials.

Contents of the invention

In view of the above existing problems, the present invention aims to provide a carbon nanotube/Ni porphyrin loaded wave-absorbing material and its preparation method and application. In the present invention, CNTs and Ni porphyrin materials are effectively compounded at the nanoscale, and the prepared CNTs/Ni porphyrin-loaded composite material has the characteristics of high absorption strength, thin matching thickness, light weight, and strong oxidation resistance. At the same time, the present invention The preparation method of the method is simple and easy, low in cost, and has great industrial application prospects.

In order to realize the above-mentioned purpose of the invention, the present invention discloses the following technical solutions:

The first aspect of the present invention provides a carbon nanotube/Ni porphyrin-supported wave-absorbing material.

A carbon nanotube/Ni porphyrin-loaded wave-absorbing material, which is a three-dimensional network structure in which one-dimensional fibers are interwoven, and the one-dimensional fiber is composed of a carbon nanotube matrix and 5,10,15,20-tetra(4 -Aminophenyl)porphyrin nickel-loaded thin layer composition, wherein, the 5,10,15,20-tetrakis(4-aminophenyl)porphyrin nickel-loaded thin layer is distributed on the surface of the carbon nanotube substrate.

As a further technical solution, in the wave-absorbing material, in the one-dimensional fiber, the percentage by weight of Ni is 0.03%-0.23%. The loading amount (percentage by weight) of 5,10,15,20-tetrakis(4-aminophenyl)porphyrin is 0.37%-2.86%.

As a further technical solution, in the absorbing material, the one-dimensional fiber has a length of 10-30 μm and a diameter of 10-20 nm.

Porphyrin and its derivatives have extensive electronic conjugation, stable central metal ions, and structural tailoring capabilities, making them ideal candidates for the development of wave-absorbing materials. After porphyrin is combined with CNTs, a rich heterogeneous structure can be formed at the interface, which may be more conducive to the regulation of electromagnetic parameters of CNTs. In addition, porphyrin derivatives with π-planar structure can build multidimensional heterostructures on the π-electron plane of carbon nanotubes and create intimate electrical contacts at the interface of the two.

In the present invention, for the first time, the porphyrin derivative [5,10,15,20-tetrakis(4-aminophenyl)porphyrin nickel, Ni-TAPP] is synthesized in a non-covalent π-π interaction through a simple self-assembly method Driven to bind effectively with CNTs. The material has a minimum reflection loss (RL) of -66.5dB (10.1GHz, 1.9mm) and a fill factor as low as 2.86%. The remarkable improvement in performance stems from the synergy of structure and function, which guarantees optimized impedance matching, reasonable conduction loss, and enhanced interfacial polarization.

One of the characteristics of the microwave-absorbing material prepared by the present invention is: compared with CNTs, the excellent performance of Ni-TAPP@CNTs is due to the synergistic effect of Ni-TAPP and CNTs. First, CNTs with good conductivity provide a long channel for the continuous flow of electrons, which may increase the conduction loss. Furthermore, CNTs can be easily constructed into a three-dimensional conductive network, which further enhances the conduction loss and provides a pathway for the diffusion of accumulated energy. Secondly, after introducing Ni-TAPP on the surface of carbon nanotubes, due to the good semiconductor properties of porphyrin, the Ni-TAPP@CNTs composite can obtain suitable electrical conductivity, taking advantage of the advantages of carbon nanotubes and Ni-TAPP to achieve good Impedance matching and optimized conduction loss. The introduction of Ni-TAPP leads to the appearance of magnetic loss including natural resonance or exchange resonance, which further leads to the attenuation capability. Third, porphyrin molecules provide single-atom metal centers that are fully dispersed and ordered, thereby effectively reducing the metal loading. In addition, the special hollow structure and three-dimensional network of Ni-TAPP@CNTs nanotubes can improve the dielectric loss and promote multiple reflection and absorption.

In a second aspect, the present invention provides a method for preparing a carbon nanotube/Ni porphyrin-supported wave-absorbing material, comprising the steps of:

Disperse the carbon nanotubes in the DMF solution, then soak the dispersed carbon nanotubes in the Ni-TAPP DMF solution for 24 hours; centrifuge, wash and dry to obtain the carbon nanotube/Ni porphyrin loaded wave-absorbing material.

As a further technical solution, the reaction mixture was centrifuged at 10,000 rpm for 10 min, washed with DMF for 3 to 5 times to remove excess Ni-TAPP, and Ni-TAPP-loaded CNTs were obtained after drying.

As a further technical solution, the different loadings of Ni-TAPP in Ni-TAPP@CNTs are controlled by adding the concentration of Ni-TAPP in DMF solution, and the concentration can be 0.1-10 mg/mL. Further, 1- 2mg/mL.

As a further technical solution, the carbon nanotubes are dispersed in the DMF solution, and the concentration of the carbon nanotubes in the DMF solution is 0.1-1.2 mg/mL.

As a further technical solution, the conditions for dispersing carbon nanotubes in DMF are as follows: 20 mg of carbon nanotubes are dispersed in 4 mL of DMF solution, and ultrasonication is applied for 3 hours.

As a further technical solution, the centrifugation condition of the reaction mixture is 10000 rpm for 10 min.

As a further technical solution, the carbon nanotube drying condition is vacuum drying at 90° C. for 12 hours.

The principle of the preparation method of the present invention is in-situ self-assembly driven by π-π interaction.

The invention uses the self-assembly method to prepare the composite material supported by hollow carbon nanotubes, and builds an interwoven network structure. Such a microstructure can provide a larger specific surface area, long-range conductance loss, and is conducive to electromagnetic waves. The multiple reflection and multiple scattering are beneficial to further improve the electromagnetic wave absorption performance; at the same time, the interwoven network structure can effectively introduce air, reduce the relative dielectric constant of the material, and help improve the impedance matching performance of the material.

The third aspect of the present invention provides a carbon nanotube/Ni porphyrin loaded electromagnetic wave absorber, the carbon nanotube/Ni porphyrin loaded electromagnetic wave absorber is made of paraffin and the carbon nanotube/Ni porphyrin prepared by the present invention The loaded absorbing material is compounded. Preferably, 90wt% of paraffin, 10wt% of carbon nanotube/Ni porphyrin loaded wave-absorbing material.

In the fourth aspect of the present invention, the carbon nanotube/Ni porphyrin-loaded wave-absorbing material and the carbon nanotube/Ni-porphyrin-loaded electromagnetic wave absorber are provided in radio communication systems, anti-high frequency, microwave heating equipment, and microwave anechoic chambers. , stealth technology, etc.

Compared with the prior art, the present invention has achieved the following beneficial effects:

(1) The Ni-TAPP@CNTs absorbing material prepared by the present invention has multiple loss characteristics, has excellent impedance matching performance and unique microscopic morphology, and can maintain a suitable medium in the high frequency range. Electrical constant, has very excellent electromagnetic wave absorption performance.

(2) Carbon nanotubes have the characteristics of light weight, and the loaded porphyrin material has a very low density and a small loading capacity, so the Ni-TAPP@CNTs absorbing material prepared by the present invention can be used to prepare light, Thin electromagnetic wave absorber.

(3) The Ni-TAPP@CNTs absorbing material prepared by the present invention has excellent impedance matching performance; the absorber made by the absorber has an effective absorption frequency bandwidth up to 6.8 GHz under a single matching thickness.

(4) The scale of Ni-TAPP@CNTs absorbing material prepared by the present invention is uniform, and the anti-oxidation and corrosion resistance are strong.

(5) The preparation process of the present invention is simple and does not require complex hardware equipment. At the same time, the production cost is low, and it is very suitable for industrial production.

Description of drawings

The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention, and the schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations to the present invention.

Figure 1 is the SEM image of the Ni-TAPP@CNTs absorbing material prepared in Example 1 of the present invention.

Fig. 2 is a TEM image of the Ni-TAPP@CNTs absorbing material prepared in Example 1 of the present invention.

Fig. 3 is the XRD diffraction pattern of the Ni-TAPP@CNTs absorbing material prepared in Example 1 of the present invention.

Fig. 4 is the electromagnetic wave absorption curve of the Ni-TAPP@CNTs absorbing material prepared in Example 1 of the present invention.

Fig. 5 is the electromagnetic wave absorption curve of the Ni-TAPP@CNTs absorbing material prepared in Test Example 1 of the present invention.

Fig. 6 is the electromagnetic wave absorption curve of the unloaded CNTs absorbing material prepared in Test Example 2 of the present invention.

Detailed ways

It should be noted that the following detailed description is exemplary and intended to provide further explanation of the present invention. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

It should be noted that the terminology used here is only for describing specific embodiments, and is not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly dictates otherwise, the singular is intended to include the plural, and it should also be understood that when the terms "comprising" and/or "comprising" are used in this specification, they mean There are features, steps, operations, means, components and/or combinations thereof.

As mentioned above, CNTs material, as a conductance loss type carbonaceous absorbing material, cannot provide appropriate dielectric polarization loss and magnetic loss, so the loss performance is not high enough. According to the impedance matching conditions in the electromagnetic wave absorption theory, it is difficult to meet the impedance matching conditions and obtain excellent electromagnetic wave absorption performance if only a single carbon material is used, which also limits its further development and application. Therefore, the present invention proposes a Ni-TAPP@CNTs microwave-absorbing material and its preparation method; the present invention will be further described in conjunction with the accompanying drawings and specific implementation methods.

Example 1

A preparation method of Ni-TAPP@CNTs wave-absorbing material, comprising the steps of:

Disperse 20mg of CNTs in 4mL of DMF solution, sonicate for 3h, and then soak the dispersed CNTs in 2mg/mL of Ni-TAPP in DMF for 24h. The reaction mixture was centrifuged at 10,000 rpm for 10 min, washed with DMF 3 to 5 times to remove excess Ni-TAPP, and vacuum-dried at 90°C for 12 h to obtain Ni-TAPP@CNTs-2.

Example 2

A preparation method of Ni-TAPP@CNTs wave-absorbing material, comprising the steps of:

Disperse 20mg of CNTs in 4mL of DMF solution, sonicate for 3h, and then soak the dispersed CNTs in 1mg/mL of Ni-TAPP in DMF for 24h. The reaction mixture was centrifuged at 10,000 rpm for 10 min, washed with DMF 3 to 5 times to remove excess Ni-TAPP, and vacuum-dried at 90°C for 12 h to obtain Ni-TAPP@CNTs-1.

Test example 1

A preparation method of an unloaded CNTs wave-absorbing material, comprising the steps of:

CNTs were reagent grade, used as received, and purchased from XFNANO Inc/Co. (10-30 [mu]m length, 10-20 nm diameter).

Performance Testing:

(1) The Ni-TAPP@CNTs absorbing material prepared in Example 1 was observed under SEM and TEM, and the results are shown in Figure 1 and Figure 2 respectively. It can be seen that after Ni-TAPP is loaded, the Still in the tubular morphology, the MWCNTs of the Ni-TAPP@CNTs-2 hybrid material are uniformly coated with the grown Ni-TAPP thin-layer nanoshells. In addition, no diffraction rings were found in the TEM images, indicating that Ni-TAPP@CNTs have no crystallinity at all.

(2) Carry out XRD test on the Ni-TAPP@CNTs absorbing material prepared in Example 1, the result is shown in Figure 3, it can be seen that: all original carbon nanotubes Ni-TAPP@CNTs-1 and Ni-TAPP@ CNTs-2 has a common characteristic peak of about 25.8° at the 2θ value, which belongs to the characteristic diffraction peak of hexagonal graphite in the (002) plane of carbon nanotubes. Ni-TAPP@CNTs-1 and Ni-TAPP@CNTs-2 have a broad peak at 2θ = 21.29°, which is due to the π-π stacking distance between the porphyrin ring and the carbon nanotube. In addition, the XRD pattern of Ni-TAPP@CNTs-2 shows a relatively weak peak at 2θ = 19.16°, which is refracted by the (300) plane of TAPP, indicating the long-range order of the molecule along this direction distributed.

(3) The Ni-TAPP@CNTs absorbing material prepared in Example 1 was tested by inductively coupled plasma emission spectrometer (ICP), and the Ni mass ratio of Ni-TAPP@CNTs-1 and Ni-TAPP@CNTs-2 (wt .%) were 0.03% and 0.23% respectively, thus calculating the loading mass ratio of porphyrin to be 0.37% and 2.86% respectively.

(4) Mix the Ni-TAPP@CNTs-2 absorbing material prepared in Example 1 with paraffin wax at a mass ratio of 1:9 and press it into a ring-shaped absorber sample ( _Douter × _dinner ×h=7× 3.04×2.0mm), the relevant parameters are measured by Agilent Technologies E8363A electromagnetic wave vector network analyzer, the electromagnetic wave absorption curve of the absorber is shown in Figure 4, the matching thickness is 1.9mm, and the maximum absorption intensity is reached when the frequency is 10.1GHz, and its reflection loss It is -66.5dB, indicating that the sample has a strong electromagnetic wave loss capability.

(5) Mix the Ni-TAPP@CNTs-1 wave-absorbing material prepared in Example 2 with paraffin at a mass ratio of 1:9 and press it into a ring-shaped absorber sample ( _Douter × _dinner ×h=7× 3.04 × 2.0mm), the relevant parameters ε _r and μ _r are measured with an Agilent Technologies E8363A electromagnetic wave vector network analyzer, and the electromagnetic wave absorption curve of the absorber is shown in Figure 5. It can be seen that due to the reduction of Ni-TAPP load, Although the material maintains a certain absorption strength, the anti-matching performance of the material becomes worse, and the matching thickness is significantly increased, which limits the application of the material in electromagnetic wave absorption. Applications in some special fields.

(6) Mix the unloaded MWCNTs absorbing material prepared in Test Example 1 with paraffin at a mass ratio of 1:9 and press it into a ring-shaped absorber sample ( _Douter × _dinner ×h=7×3.04× 2.0mm), the relevant parameters _εr and _μr are measured by Agilent Technologies E8363A electromagnetic wave vector network analyzer, and the electromagnetic wave absorption curve of the absorber is shown in Figure 6. It can be seen that without the load of Ni-TAPP, the absorption strength of the material It is greatly reduced, but the anti-matching performance of the material is further deteriorated, and the matching thickness is further increased, which is not conducive to the absorption of electromagnetic waves, which greatly limits the application of materials in electromagnetic wave absorption.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (6)

1. The preparation method of the CNTs/Ni porphyrin loaded wave-absorbing material is characterized by comprising the following steps of:

dispersing carbon nanotubes in DMF solution, and then soaking the dispersed carbon nanotubes in DMF solution of 5,10,15, 20-tetra (4-aminophenyl) porphyrin nickel for 24 hours; centrifuging, cleaning and drying the reaction mixture to obtain the CNTs/Ni porphyrin loaded wave-absorbing material;

the condition that the carbon nano tube is dispersed in DMF is that 20mg carbon nano tube is dispersed in 4mL DMF solution, and the ultrasonic effect is 3 h;

the concentration of the solution of the 5,10,15, 20-tetra (4-aminophenyl) porphyrin nickel in DMF is 2 mg/mL;

the CNTs/Ni porphyrin-loaded wave-absorbing material is of a three-dimensional network structure with one-dimensional fibers interwoven with each other, wherein the one-dimensional fibers consist of a carbon nanotube matrix and a 5,10,15, 20-tetra (4-aminophenyl) porphyrin nickel-loaded thin layer, and the 5,10,15, 20-tetra (4-aminophenyl) porphyrin nickel-loaded thin layer is distributed on the surface of the carbon nanotube matrix;

in the one-dimensional fiber, the weight percentage of Ni is 0.03%; the weight percentage of 5,10,15, 20-tetra (4-aminophenyl) porphyrin was 0.37%.

2. The method according to claim 1, wherein the one-dimensional fiber has a length of 10 to 30 μm and a diameter of 10 to 20nm.

3. The method of claim 1, wherein the centrifugation conditions are: centrifuging at 10000rpm for 10 min; and the cleaning is to use DMF for 3-5 times.

4. The method of claim 1, wherein the carbon nanotube drying condition is vacuum drying 12h at 90 ℃.

5. The carbon nano tube/Ni porphyrin loaded electromagnetic wave absorber is characterized by being formed by compounding paraffin and the CNTs/Ni porphyrin loaded electromagnetic wave absorbing material prepared by the preparation method of any one of claims 1-4.

6. The CNTs/Ni porphyrin-loaded wave-absorbing material prepared by the preparation method of any one of claims 1-4 and/or the carbon nano tube/Ni porphyrin-loaded electromagnetic wave absorber of claim 5 are applied to a radio communication system, a high-frequency-resistant microwave heating device, a microwave darkroom construction and a stealth technology.