A melamine-titanium carbide@cobalt-nickel composite foam material, its preparation method and application

Abstract

The present invention belongs to the technical field of composite materials, and particularly relates to a melamine-titanium carbide@cobalt-nickel composite foam material, a preparation method thereof, and an application thereof. In the present invention, three-dimensional melamine foam is used as a matrix, and titanium carbide and cobalt-nickel metal particles are compounded on its surface through a vacuum impregnation and electrostatic self-assembly process to obtain a melamine-titanium carbide@cobalt-nickel composite foam material. The melamine-titanium carbide@cobalt-nickel composite foam material prepared by the present invention can effectively absorb electromagnetic waves, can effectively absorb near-infrared light, and can effectively inhibit Escherichia coli.

Description

Technical Field

[0001] The present invention belongs to the technical field of composite materials, and particularly relates to a melamine-titanium carbide@cobalt-nickel composite foam material, a preparation method thereof, and an application thereof. Background Art

[0002] With the rapid development of modern science and technology, especially in the fields of aerospace, electronic information, biomedicine, etc., the demand for high-performance electromagnetic wave absorbing materials is increasing day by day. These materials not only need to have excellent electromagnetic wave absorption ability to solve the increasingly serious electromagnetic interference and electromagnetic radiation problems, but also should take into account characteristics such as light weight, environmental friendliness, and multifunctionality. In recent years, new composite absorbing materials with both photothermal conversion and antibacterial functions have become a research hotspot. While improving the performance of electronic devices, they can also effectively meet the needs of photothermal therapy and antibacterial protection. Ti3C2T X As an emerging two-dimensional material, due to its unique physical and chemical properties, such as high specific surface area, good electrical conductivity, and adjustable surface chemical properties, it shows great potential in the field of electromagnetic wave absorption. By combining it with a melamine foam matrix, not only can the dielectric properties of the material be optimized, but also the electromagnetic wave absorption ability can be enhanced through the interfacial polarization effect. In addition, the three-dimensional pore structure of the melamine foam and Ti3C2T X 's surface plasmon resonance effect bring a relatively high photothermal conversion efficiency, providing a basis for the photothermal and antibacterial applications of the material. However, Ti3C2T X has problems such as single loss, weak absorption intensity, and poor impedance matching, and further improvement is still needed. Cobalt-nickel alloy, as a typical magnetic material, has good magnetic loss characteristics and can effectively absorb and dissipate electromagnetic wave energy.

[0003] By introducing magnetic materials such as cobalt and nickel, a multi-phase heterogeneous structure can be formed. The synergistic effect of magnetic loss and dielectric loss can further improve the electromagnetic wave absorption performance of the material. The prior art discloses a 2D / 0D / 1D structure MXene-CoNi@NCNT composite material obtained by in-situ growing zero-dimensional CoNi nanoalloys encapsulated one-dimensional nitrogen-doped carbon nanotubes on two-dimensional sheet Ti3C2T x The special structure and the synergistic effect of dielectric / magnetic loss of this material optimize the impedance matching and enhance the attenuation ability. When the coating thickness is 2.1 mm, the best reflection loss value reaches -55.3 dB (J. Cheng, B. Liu, Y. Wang, H. Zhao, Y. Wang. Journal of Materials Science & Technology, 2022, 30(3): 343-351). The prior art also discloses a method of assembling magnetized Ni flowers and Ti3C2T on the surface of melamine foam XThe Ni-MXene / MF composite foam obtained from MXene has a best reflection loss value of -62.7 dB when the matching thickness is 2.0 mm, and an effective absorption bandwidth of 6.88 GHz when the thickness is 1.8 mm (H. Cheng, Y. Pan, X. Wang, et al. Nano-Micro Lett, 2022, 130: 157-165.). Existing preparation technologies mainly focus on the synthesis of single-functional materials. However, for the preparation of composite materials with multiple functions (such as electromagnetic wave absorption, photothermal conversion, and antibacterial properties), there are still problems such as complex synthesis processes, difficult-to-balance material properties, and high costs. Therefore, developing a simple, efficient, and environmentally friendly preparation method to prepare multifunctional composite absorbing materials with excellent performance and stable structure is of great significance for promoting the multifunctionalization process of electromagnetic wave absorbing materials. Summary of the Invention

[0004] Aiming at the problems of existing absorbing materials, such as single type, small reflection loss, and narrow absorption bandwidth, the present invention provides a preparation method and application of a melamine-titanium carbide@cobalt-nickel composite foam material with both photothermal antibacterial and wave-absorbing properties. The melamine-titanium carbide@cobalt-nickel composite foam material is formed by compounding a high-dielectric-loss and strong-magnetic-loss material with melamine foam, resulting in a multi-component lightweight broadband composite absorbing foam material. The preparation process is simple, efficient, and low-cost.

[0005] Using three-dimensional melamine foam as the matrix, titanium carbide and cobalt-nickel metal particles are compounded on its surface through vacuum impregnation and electrostatic self-assembly processes to obtain the melamine-titanium carbide@cobalt-nickel composite foam material. The melamine-titanium carbide@cobalt-nickel composite foam material prepared by the present invention has multiple loss mechanisms, advantages such as strong reflection loss and wide microwave absorption bandwidth, and can effectively absorb electromagnetic waves.

[0006] To achieve the above technical objectives, the technical solution of the present invention is as follows:

[0007] A preparation method of a melamine-titanium carbide@cobalt-nickel composite foam material includes the following steps:

[0008] S1. Clean and pre-treat the melamine foam, then place the treated melamine foam in a Tris buffer solution containing hydrochloric acid dopamine (PDA) and stir, and then wash it with deionized water multiple times and dry it for standby;

[0009] S2. Ultrasonically treat cobalt-nickel particles in a cetyltrimethylammonium bromide (CTAB) solution for 30 min, and dry to obtain cobalt-nickel particle (CTAB) material. Stir and ultrasonically treat titanium carbide powder and cobalt-nickel particle (CTAB) in deionized water for 30 min until uniform, and dry to obtain titanium carbide@cobalt-nickel composite material;

[0010] S3. Disperse the titanium carbide@cobalt-nickel composite material obtained in S2 in deionized water to obtain a titanium carbide@cobalt-nickel solution, and vacuum impregnate the melamine foam obtained in S1 in the titanium carbide@cobalt-nickel solution for 2 h, then dry to obtain a melamine-titanium carbide@cobalt-nickel composite foam material.

[0011] Further, the concentration of dopamine hydrochloride (PDA) in the Tris buffer solution is 1 - 5 mg / mL.

[0012] Further, the concentration of cetyltrimethylammonium bromide (CTAB) solution is 1 - 5 mg / mL.

[0013] In the present invention, first, titanium carbide (TiC) and cobalt-nickel particles are first compounded and then loaded onto melamine foam (MF). Compared with the prior art of directly loading titanium carbide and cobalt-nickel particles onto melamine step by step, it has the following advantages:

[0014] (1) During the compounding process, the titanium carbide and cobalt-nickel particles have been fully mixed and dispersed. Therefore, when the composite material is loaded onto the melamine foam, it can be more evenly distributed. Each component of the composite material (Ti3C2 and CoNi) can provide better overall performance through synergistic effects. If the individual cobalt-nickel and titanium carbide particles are directly loaded onto the melamine foam, particle aggregation may occur, resulting in uneven material distribution and affecting the performance of the composite material, especially mechanical properties, thermal properties, and electromagnetic absorption properties, etc.

[0015] (2) Improve the interfacial bonding strength:

[0016] By compounding first, a certain bonding force has been formed between the cobalt-nickel particles and the titanium carbide particles through physical adsorption or chemical interaction. In this way, the interfacial bonding force of the composite material will be enhanced, reducing the possible separation or shedding phenomenon of the cobalt-nickel and titanium carbide particles during the loading process. If directly loaded, the bonding force between cobalt-nickel and titanium carbide is weak, which may cause the particles to be unstable on the foam surface, especially when the external environment changes, the particles are prone to shedding or uneven dispersion.

[0017] (3) Improve the stability and controllability of the composite material:

[0018] By compounding first, the composition and structure of the composite material are easier to control, ensuring that the composite material loaded on the foam surface is stable and has a well-matched ratio, thereby improving the stability of the final composite material. Direct loading may lead to incomplete interaction between materials. Especially when the particles are not fully dispersed or have no good surface modification, there may be uneven physical or chemical bonding forces on the surface of the foam, resulting in instability of the composite.

[0019] Disadvantages that can be overcome

[0020] (1) Agglomeration and uneven dispersion of particles:

[0021] Composite first and then load can overcome the problem of particle agglomeration that may occur during the direct and separate loading process. Through the composite, titanium carbide and cobalt-nickel particles have been evenly distributed, thus avoiding the situation where particles agglomerate on the foam surface due to poor dispersion during direct loading.

[0022] (2) Problem of unstable interface:

[0023] If cobalt-nickel and titanium carbide are directly and separately loaded onto melamine foam, the interfacial bonding force between the particles and the foam may be weak. By composite first, the bonding force between the particles can be improved during the composite process, enhancing the interfacial stability of the final composite material and reducing the risk of particle shedding or material delamination.

[0024] (3) Unstable performance of the composite material:

[0025] Composite first and then load can ensure that the composite material loaded onto melamine foam has good stability, avoiding the problem of inconsistent performance caused by unstable materials or uneven dispersion during the separate loading process. In the case of direct loading, due to the possible incomplete uniform distribution of cobalt-nickel and titanium carbide particles, the performance of the composite material fluctuates or shows non-uniformity during use.

[0026] (3) Fragmentation or shedding during the loading process:

[0027] Composite first and then load can avoid problems such as particle shedding, fragmentation or dissolution during the loading process. Especially during the material loading process, the structural stability of the composite is better, which can reduce the unevenness or shedding of the composite material on the foam surface.

[0028] In summary, compared with directly loading titanium carbide and cobalt-nickel particles separately onto melamine foam, the method of composite first and then load can ensure more uniform particle distribution, stronger interfacial bonding force and higher stability, overcoming problems such as particle agglomeration, uneven distribution and unstable interface that may occur during the direct loading process, thereby improving the performance and stability of the composite material.

[0029] Furthermore, the preparation method of the titanium carbide powder includes the following steps: dissolve LiF in HCl solution, then add Ti3AlC2, stir at room temperature for 24 h, wash by centrifugation repeatedly until pH = 6, collect the precipitate, disperse the precipitate in deionized water, and obtain the titanium carbide powder after ultrasonic treatment, centrifugation and drying for 1 h.

[0030] Furthermore, the preparation method of the cobalt-nickel particles includes the following steps:

[0031] S1. Add Co(NO3)2·6H2O and Ni(NO3)2·6H2O to methanol and stir evenly to form solution A; then dissolve dimethylimidazole and polyvinylpyrrolidone (K30) in methanol to form solution B; drop solution B into solution A, stir for 6 h, and obtain the CoNi-MOFs precursor after centrifugation and drying.

[0032] S2. Pyrolyze the CoNi-MOFs precursor in a tubular furnace under an argon atmosphere at a heating rate of 5 ° / min, hold at 800 °C - 900 °C for 2 h, and cool to obtain cobalt-nickel particles.

[0033] In the present invention, the calcination temperature cannot be lower than 800 °C and cannot exceed 900 °C. When the calcination temperature is lower than 800 °C, the crystallinity of the metal cobalt-nickel particles reduced from the CoNi-MOFs precursor is relatively low, the dispersion between particles is poor, and the magnetic properties and other functional properties may be significantly affected. Therefore, it is very important to ensure that the calcination temperature is higher than 800 °C, which can ensure the complete reduction of the metal cobalt-nickel particles, the uniform distribution of the particles, and good properties.

[0034] When the calcination temperature exceeds 900 °C, it will lead to overgrowth, agglomeration or sintering of the metal particles, resulting in the loss of the surface area and functionality of the material; high temperature may also damage the porous structure of the MOF, leading to a decline in properties such as catalysis and adsorption; at the same time, it may also cause the generation of by-products, affecting the purity and properties of the material. Therefore, it is necessary to carry out calcination within an appropriate temperature range to ensure the appropriate size of the metal particles, the uniform distribution, and the good properties of the material.

[0035] Further, the mass ratio of titanium carbide and cobalt-nickel particles (CTAB) is 2:1.

[0036] Further, the concentration of the titanium carbide@cobalt-nickel solution is 5 - 20 mg / mL, preferably 10 mg / mL.

[0037] The present invention also provides the application of the melamine-titanium carbide@cobalt-nickel composite foam material as a photothermal conversion material.

[0038] The present invention also provides the application of the melamine-titanium carbide@cobalt-nickel composite foam material as a photothermal antibacterial material.

[0039] The present invention also provides the application of the melamine-titanium carbide@cobalt-nickel composite foam material as an electromagnetic wave absorption material.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] (1) The melamine - titanium carbide@cobalt - nickel composite foam material with both photothermal antibacterial and wave - absorbing properties prepared by the present invention can effectively absorb near - infrared light and has excellent photothermal conversion ability. In addition, relying on the synergistic effect of each component, it can effectively inhibit Escherichia coli under the irradiation of a near - infrared lamp and has excellent photothermal antibacterial properties.

[0042] (2) The present invention uses three - dimensional melamine foam as the matrix and composes accordion - like titanium carbide and cobalt - nickel metal particles on its surface through vacuum impregnation and electrostatic self - assembly processes to obtain a composite foam material. The composite of multiple components and the regulation of different concentrations can effectively adjust the dielectric constant of the material, endowing it with excellent impedance matching characteristics and strong loss ability.

[0043] (3) The three - dimensional porous structure constructed by the present invention forms a cross - linked network structure inside the material, providing a conductive path. The highly conductive titanium carbide helps to enhance the conduction loss. The cobalt - nickel particles and titanium carbide are assembled on the melamine skeleton, forming a large number of heterogeneous interfaces, bringing magnetic loss while obtaining high polarization loss. The synergistic effect of multiple components and multiple loss mechanisms can significantly improve the absorption ability of incident electromagnetic waves.

[0044] (4) The melamine - titanium carbide@cobalt - nickel composite foam material with both photothermal antibacterial and wave - absorbing properties provided by the present invention has an effective absorption bandwidth as high as 7.8 GHz at a thickness of 2.5 mm; the best reflection loss value is - 51.4 dB, possessing excellent absorption performance and lightweight wide - band characteristics, and can be applied to fields such as wireless communication devices, radar detection, stealth technology, and other electromagnetic protection. Description of the Drawings

[0045] Figure 1 SEM image of the melamine - titanium carbide@cobalt - nickel composite foam material of Example 2 of the present invention.

[0046] Figure 2 XRD diffraction pattern of the melamine - titanium carbide@cobalt - nickel composite foam material of Example 2 of the present invention.

[0047] Figure 3 Electromagnetic parameter diagram of the electromagnetic wave - absorbing material of Example 1 of the present invention in the frequency range of 2 - 18 GHz.

[0048] Figure 4 Reflection loss diagram of the electromagnetic wave - absorbing material of Example 1 of the present invention in the frequency range of 2 - 18 GHz.

[0049] Figure 5 Electromagnetic parameter diagram of the electromagnetic wave - absorbing material of Example 2 of the present invention in the frequency range of 2 - 18 GHz.

[0050] Figure 6Reflection loss graph of the electromagnetic wave absorbing material of Embodiment 2 of the present invention in the frequency band of 2 - 18 GHz.

[0051] Figure 7 Electromagnetic parameter graph of the electromagnetic wave absorbing material of Embodiment 3 of the present invention in the frequency band of 2 - 18 GHz.

[0052] Figure 8 Reflection loss graph of the electromagnetic wave absorbing material of Embodiment 3 of the present invention in the frequency band of 2 - 18 GHz.

[0053] Figure 9 Electromagnetic parameter graph of the electromagnetic wave absorbing material of Comparative Example 1 of the present invention in the frequency band of 2 - 18 GHz.

[0054] Figure 10 Reflection loss graph of the electromagnetic wave absorbing material of Comparative Example 1 of the present invention in the frequency band of 2 - 18 GHz.

[0055] Figure 11 Photothermal conversion curve graph of the melamine - titanium carbide@cobalt - nickel composite foam material of Embodiment 2 of the present invention under different light power densities.

[0056] Figure 12 Photothermal conversion curve graph of the melamine - titanium carbide@cobalt - nickel composite foam material of Embodiment 2 of the present invention under gradually increasing light power densities.

[0057] Figure 13 Infrared thermal imaging graph of the melamine - titanium carbide@cobalt - nickel composite foam material of Embodiment 2 of the present invention.

[0058] Figure 14 Antibacterial effect graph of the melamine - titanium carbide@cobalt - nickel composite foam material of Embodiment 2 of the present invention. Detailed implementation manners

[0059] Embodiment 1

[0060] A preparation method of a melamine - titanium carbide@cobalt - nickel composite foam material, comprising the following steps:

[0061] (1) Dissolve 3.6 g of LiF in HCl solution (9 M), then add 2.2 g of Ti3AlC2, stir at room temperature for 24 h, repeatedly centrifuge and wash until pH = 6, collect the precipitate and disperse it in deionized water. After ultrasonic treatment, centrifugation and drying for 1 h, titanium carbide powder is obtained.

[0062] (2) Add Co(NO3)2·6H2O and Ni(NO3)2·6H2O to 30 mL of methanol and stir evenly to form solution A; then dissolve dimethylimidazole and polyvinylpyrrolidone (K30) in 20 mL of methanol to form solution B; drip solution B into solution A, stir for 6 h, and obtain the CoNi-MOFs precursor after centrifugation and drying. The molar ratio of Co(NO3)2·6H2O and Ni(NO3)2·6H2O used is 1:0.5 - 1:4, and the mass ratio of dimethylimidazole to Ni(NO3)·3H2O is 3:1.

[0063] (3) Pyrolyze the CoNi-MOFs precursor in an argon atmosphere in a tube furnace at a heating rate of 5 ° / min, hold at 800 °C for 4 h, and cool to obtain cobalt-nickel particles.

[0064] (4) Ultrasonically treat the melamine foam with ethanol and deionized water for 30 min respectively, put the treated melamine foam into 50 mL of Tris buffer solution containing hydrochloric acid dopamine (PDA) and stir for 12 h, then wash it with deionized water multiple times and dry for standby. The concentration of hydrochloric acid dopamine (PDA) in the Tris buffer solution used is 1 - 5 mg / mL.

[0065] (5) Ultrasonically treat the cobalt-nickel particles in cetyltrimethylammonium bromide (CTAB) solution for 30 min, and dry to obtain cobalt-nickel particles (CTAB) material. Stir and ultrasonically treat titanium carbide and cobalt-nickel particles (CTAB) in deionized water for 30 min until uniform, and dry to obtain titanium carbide@cobalt-nickel composite material. The concentration of the cetyltrimethylammonium bromide (CTAB) solution used is 1 - 5 mg / mL, and the mass ratio of titanium carbide to cobalt-nickel particles (CTAB) used is 2:1.

[0066] (6) Finally, fully vacuum impregnate the melamine foam in (4) in a 20 mg / mL titanium carbide@cobalt-nickel solution for 2 h to complete electrostatic assembly, and obtain the melamine-titanium carbide@cobalt-nickel-20 composite foam material after drying.

[0067] Example 2

[0068] The difference between Example 2 and Example 1 is that the concentration of the titanium carbide@cobalt-nickel solution is 10 mg / mL, and the other conditions are exactly the same.

[0069] Example 3

[0070] The difference between Example 3 and Example 1 is that the concentration of the titanium carbide@cobalt-nickel solution is 5 mg / mL, and the other conditions are exactly the same.

[0071] Comparative Example 1

[0072] The cobalt-nickel particle composite material prepared in step (2) of Example 1 was made into a microwave absorber, and its microwave absorption performance was tested.

[0073] The melamine-titanium carbide@cobalt-nickel composite foam prepared in Example 2 was observed under a scanning electron microscope, and the results are as Figure 1 shown: The melamine-titanium carbide@cobalt-nickel composite foam has a three-dimensional porous structure, and titanium carbide@cobalt-nickel is uniformly coated on the melamine skeleton, with a diameter between 500 nm and 1 μm.

[0074] The melamine-titanium carbide@cobalt-nickel composite foam prepared in Example 2 was tested by X-ray diffraction (XRD), and the results are as Figure 2 shown: The main components of the crystalline phase in the synthesized composite material are titanium carbide, cobalt (JCPDS-15-0806), and nickel (JCPDS-04-0850). The XRD results indicate that the melamine-titanium carbide@cobalt-nickel-20 composite foam material was successfully prepared by this technical solution.

[0075] The microwave absorption performance of the melamine-titanium carbide@cobalt-nickel composite foam prepared in Examples 1-3 was tested: The composite foam material was made into a microwave absorber and its microwave absorption performance was tested. The melamine-titanium carbide@cobalt-nickel composite foam material was mixed with paraffin at a mass fraction of 40% to make a coaxial ring absorber (D 外 = 7 mm, d 内 = 3.04 mm). The complex permittivity (ε r ) and complex permeability (μ r ) in the frequency range of 2-18 GHz were measured by an Agilent Technologies N5244A electromagnetic wave vector network analyzer. The reflection loss is determined by ε r , μ r , the absorption frequency, and the thickness of the absorber.

[0076] The permittivity ε r of the absorber prepared in Example 1 is as Figure 3 shown, and the microwave absorption performance calculated from ε r is as Figure 4As shown, the optimal reflection loss of this absorber is -20.7 dB at a low thickness of 1.5 mm. The reflection loss is less than -10 dB in the range of 12.8 - 18.0 GHz, and the effective absorption bandwidth is 5.2 GHz. When the thickness is 2.0 mm, the minimum reflection loss is -18.5 dB, and the effective absorption bandwidth at this thickness is 3.5 GHz. When the thickness is 2.5 mm, the minimum reflection loss is -17.6 dB, and the effective absorption bandwidth at this thickness is 2.7 GHz. When the absorber thickness increases to 3 mm, the minimum reflection loss is -20.5 dB, and the effective absorption bandwidth is 3.5 GHz. When the thickness is 3.4 mm, the minimum reflection loss is -16.9 dB, and the effective absorption bandwidth is 1.8 GHz. When the thickness is 4.3 mm, the minimum reflection loss is -15.8 dB, and the effective absorption bandwidth is 1.3 GHz. When the thickness is 5 mm, the minimum reflection loss is -14.3 dB, and the effective absorption bandwidth is 1.0 GHz. There is an effective absorption range with a reflection loss value less than -10 dB at all thicknesses.

[0077] The dielectric constant ε of the absorber prepared in Example 2 r As Figure 5 shown, the absorption performance calculated from ε r is as Figure 6 shown. The optimal reflection loss of this absorber is -14.1 dB at a thickness of 2.0 mm. The reflection loss is less than -10 dB in the range of 14.7 - 18.0 GHz, and the effective absorption bandwidth is 3.3 GHz. The optimal reflection loss of the absorber is -19.2 dB at a thickness of 2.5 mm. The reflection loss is less than -10 dB in the range of 10.2 - 18 GHz, and the effective absorption bandwidth is as high as 7.8 GHz. When the absorber thickness is 3.0 mm, the optimal reflection loss is -31.5 dB, and the effective absorption bandwidth is 3.2 GHz. When the thickness is 3.4 mm, the optimal reflection loss value can reach -51.4 dB, and the effective absorption bandwidth is 3.2 GHz, showing excellent electromagnetic wave absorption performance. When the thickness is 4.3 mm, the optimal reflection loss is -38.1 dB, and the effective absorption bandwidth is 2.2 GHz. When the thickness is 5.0 mm, the optimal reflection loss is -22.3 dB, and the effective absorption bandwidth is 2.0 GHz. There is an effective absorption range with a reflection loss value less than -10 dB at all thicknesses.

[0078] The dielectric constant ε of the absorber prepared in Example 3 r As Figure 7 shown, the absorption performance calculated from ε r is as Figure 8As shown, when the thickness of the absorber is 3.0 mm, the best absorption performance is achieved, and the minimum reflection loss is -6.6 dB; when the thickness is 1.5 mm, the minimum reflection loss is -1.9 dB; when the thickness is 2.0 mm, the minimum reflection loss is -3.9 dB; when the thickness is 3.4 mm, the minimum reflection loss is -5.4 dB; when the thickness is 5.0 mm, the minimum reflection loss is -3.7 dB; at all thicknesses, there is no reflection loss value less than -10 dB, and there is no effective absorption bandwidth.

[0079] The dielectric constant ε of the absorber prepared in Comparative Example 1 r As Figure 9 shown, the absorption performance calculated from ε r is as Figure 10 shown. When the thickness of the absorber is 1.1 mm, the best absorption performance can be achieved, and the best reflection loss value is -11.9 dB. At this thickness, the effective absorption bandwidth is 2.7 GHz; when the thickness is 1.5 mm, the minimum reflection loss is -10.3 dB, and the effective absorption bandwidth at this thickness is 1.2 GHz; when the thickness is 2.0 mm, the minimum reflection loss is -8.4 dB; when the thickness increases to 2.5 mm, the minimum reflection loss is -7.7 dB; when the thickness is 3.4 mm, the minimum reflection loss is -6.5 dB; when the thickness is 4.3 mm, the minimum reflection loss is -6.1 dB; when the thickness is 5.0 mm, the minimum reflection loss is -5.6 dB; when the thickness is greater than 2.0 mm, there is no effective absorption bandwidth.

[0080] Through the performance analysis of the absorbers obtained in Examples 1-3 and Comparative Example 1, it can be seen that the absorber in Example 2 has the best performance, with a reflection loss value reaching -51.4 dB, achieving strong loss of electromagnetic waves, and having an absorption bandwidth value as high as 7.8 GHz (10.2 - 18 GHz) at a thickness of 2.5 mm, and the density is only 0.0185 g / cm 3 . It can meet the performance requirements of "thin, light, wide, and strong" for ideal absorbing materials. Although the absorber in Example 1 has a relatively wide effective absorption bandwidth, its loss intensity is low and it cannot achieve effective absorption of electromagnetic waves. For the absorber in Example 3, the reflection loss value does not reach -10 dB at all thicknesses, and it does not have absorption performance. In addition, for the absorber in Comparative Example 1, when the thickness is less than 2.0 mm, the loss intensity is low and the effective absorption bandwidth is narrow; when the thickness is greater than 2.0 mm, there is no loss ability at all and it cannot achieve effective absorption of electromagnetic waves.

[0081] The above description of electromagnetic wave absorption performance: The three-dimensional porous structure melamine-titanium carbide@cobalt-nickel composite electromagnetic wave absorption foam material prepared by the present invention has an effective absorption bandwidth as high as 7.8 GHz at a thickness of 2.5 mm; the best reflection loss value is -51.4 dB, featuring light weight, wide frequency band, and excellent wave absorption performance. In addition, by adjusting the concentration of the titanium carbide@cobalt-nickel solution, the loss ability of the composite material to electromagnetic waves can be significantly adjusted.

[0082] Photothermal conversion performance test of the melamine-titanium carbide@cobalt-nickel composite foam material prepared in Example 2: The melamine-titanium carbide@cobalt-nickel composite foam material prepared in Example 2 was subjected to a photothermal performance test under the irradiation of an 808 nm near-infrared laser lamp. The obtained photothermal conversion curve is as Figure 11 and Figure 12 shown, and the thermal imaging diagram taken by an infrared camera is as Figure 13 shown. Under the light power density of 200 mW / cm 2 of the near-infrared laser lamp, the temperature of the composite foam reaches 113.6 °C. By dynamically adjusting the light power density from 25 to 200 mW / cm 2 , the temperature change of the composite foam can be effectively controlled, showing excellent photothermal conversion characteristics.

[0083] Photothermal antibacterial performance test of the melamine-titanium carbide@cobalt-nickel composite foam material prepared in Example 2: The composite foam material prepared in Example 2 was subjected to an antibacterial performance test under the irradiation of an 808 nm near-infrared laser lamp. The antibacterial effect is as Figure 14 shown. Compared with the blank control group, when there is no irradiation of the near-infrared laser lamp, the reduction in the number of Escherichia coli in the petri dish containing the melamine-titanium carbide@cobalt-nickel composite foam material is not obvious; while under the light power density of 100 mW / cm 2 of the laser lamp, all the Escherichia coli in the petri dish containing the melamine-titanium carbide@cobalt-nickel composite foam material are inactivated, showing a powerful bactericidal effect and excellent photothermal antibacterial performance.

Claims

1. Application of melamine-titanium carbide@cobalt-nickel composite foam material as photothermal conversion material or photothermal antibacterial material, characterized in that: The melamine-titanium carbide@cobalt-nickel composite foam material is prepared by using three-dimensional melamine foam as a matrix and composite titanium carbide and cobalt-nickel metal particles on its surface through vacuum impregnation and electrostatic self-assembly processes; The preparation method of the melamine-titanium carbide@cobalt-nickel composite foam material comprises the following steps: S1, cleaning and pre-treating the melamine foam, then placing the treated melamine foam in a Tris buffer containing dopamine hydrochloride PDA and stirring, then washing with deionized water for multiple times, and drying for later use; S2, ultrasonically treating the cobalt-nickel particles in a hexadecyltrimethylammonium bromide solution for 30 min, drying to obtain a cobalt-nickel particle material, stirring the titanium carbide powder and the cobalt-nickel particles in deionized water, ultrasonically treating for 30 min until uniform, and drying to obtain a titanium carbide@cobalt-nickel composite material; the mass ratio of titanium carbide to cobalt-nickel particles is 2:1; S3, dispersing the titanium carbide @ cobalt nickel composite material obtained in S2 in deionized water to obtain a titanium carbide @ cobalt nickel solution, vacuum impregnating the melamine foam obtained in S1 in the titanium carbide @ cobalt nickel solution for 2 hours, and drying to obtain a melamine-titanium carbide @ cobalt nickel composite foam material; the concentration of the titanium carbide @ cobalt nickel solution is 10 mg / mL; The preparation method of cobalt-nickel particles comprises the following steps: S1. Add Co(NO3)2·6H2O and Ni(NO3)2·6H2O to methanol and stir evenly to form solution A; then dissolve dimethylimidazole and polyvinylpyrrolidone K30 in methanol to form solution B; drop solution B into solution A, stir for 6 h, and obtain CoNi-MOFs precursor after centrifugation and drying; S2. The CoNi-MOFs precursor was pyrolyzed in an argon environment of a tubular furnace at a heating rate of 5 ° / min, kept at 800 °C-900 °C for 2 h, and cooled to obtain cobalt-nickel particles.

2. The use of the melamine-titanium carbide@cobalt-nickel composite foam material according to claim 1 as a photothermal conversion material or a photothermal antibacterial material, characterized in that: The preparation method of titanium carbide powder comprises the following steps: LiF was dissolved in HCl solution, and then Ti3AlC2 was added. The mixture was stirred at room temperature for 24 h, and centrifuged and washed repeatedly until pH = 6. The precipitate was collected and dispersed in deionized water. Titanium carbide powder was obtained after ultrasonication, centrifugation and drying for 1 h.

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