Preparation method and application of carbon nanotube sponge / copper / thermoplastic polyurethane composite material

Abstract

The invention provides a preparation method and application of a carbon nanotube sponge / copper / thermoplastic polyurethane composite material. The preparation method of the composite material comprises the following steps: 1) preparing carbon nanotube sponge by adopting a chemical vapor deposition method, and removing surface impurities through plasma cleaning; (2) preparing a copper precursor solution which comprises a mixture of copper formate tetrahydrate, 2-amino-2-methyl-1-propanol and methanol, and forming a Cu-MOD solution with the concentration of 0.1 mol / L to 2.0 mol / L; (3) soaking the pretreated carbon nanotube sponge in the Cu-MOD solution, and carrying out annealing treatment at 200 DEG C in an argon atmosphere so as to deposit copper particles in situ; and 4) immersing the copper-loaded carbon nanotube sponge into a thermoplastic polyurethane / dimethylformamide solution, and fully filling pores with thermoplastic polyurethane through vacuum-assisted immersion to form the composite material. According to the invention, collaborative optimization of wide-frequency-band (GHz to THz) electromagnetic shielding and low-voltage efficient electric heating performance is realized.

Description

Technical Field

[0001] The present invention relates to the technical field of nanocomposite materials, and in particular to a method for preparing a composite material composed of carbon nanotubes (CNTs), metal (copper) and polymer (thermoplastic polyurethane) and its multifunctional applications in the fields of electromagnetic shielding, electrothermal conversion, flexible electronics, etc. Background Art

[0002] As flexible electronic devices develop towards thinner and more integrated designs, higher requirements are placed on the comprehensive performance of materials. Carbon nanotubes (CNTs) have become a research hotspot due to their light weight, high conductivity, and processability. However, the electrical conductivity of pure CNT materials is usually only about 10 3 S / m, resulting in its electromagnetic shielding effectiveness (EMI SE) being difficult to exceed 40dB, and a high driving voltage (>10V) is required to achieve effective heating.

[0003] In existing technologies, reinforcing CNT networks with metals (such as copper and silver) is an effective strategy to improve conductivity, but traditional methods such as electrodeposition and physical vapor deposition (PVD) have obvious defects: uneven distribution of metal particles, easy oxidation, and poor bonding with the polymer matrix.

[0004] For example, the conductivity of CNT / Cu composite conductors reported in the literature can reach 4.7×10 7 S / m, but it does not solve the problems of flexibility and broadband shielding; although CNT / Ag film has excellent conductivity, it requires high voltage to drive and has low heating efficiency.

[0005] In addition, existing composite materials find it difficult to achieve both wide-band (GHz to THz) electromagnetic shielding and low-voltage efficient heating in ultra-thin thickness (<200μm), which limits their application in precision flexible electronic devices.

[0006] In summary, existing carbon nanotube-based materials have deficiencies in electrical conductivity and electromagnetic shielding effectiveness (EMI SE), which limits their application in high-frequency electronic devices and wearable devices.

[0007] Therefore, there is an urgent need to develop a new type of composite material that can simultaneously possess high conductivity, excellent electromagnetic shielding performance and good flexibility to meet the needs of the next generation of electronic devices. Summary of the Invention

[0008] In order to overcome the problems of insufficient electrical conductivity and limited electromagnetic shielding effectiveness (EMI SE) of existing carbon nanotube (CNT)-based materials, the purpose of the present invention is to provide a method for preparing a carbon nanotube sponge / copper / thermoplastic polyurethane composite material, which is a flexible, ultra-thin and highly conductive composite material, and achieves the synergistic optimization of wide-band (GHz to THz) electromagnetic shielding and low-voltage and high-efficiency electrothermal performance.

[0009] In order to solve the above problems, the present invention is implemented by adopting the following technical solutions.

[0010] A method for preparing a carbon nanotube sponge / copper / thermoplastic polyurethane composite material comprises the following steps:

[0011] 1) Prepare carbon nanotube sponge by chemical vapor deposition and remove surface impurities by plasma cleaning;

[0012] 2) preparing a copper precursor solution comprising a mixture of copper formate tetrahydrate, 2-amino-2-methyl-1-propanol, and methanol to form a Cu-MOD solution with a concentration of 0.1-2.0 mol / L;

[0013] 3) soaking the pretreated carbon nanotube sponge in the Cu-MOD solution and annealing it at 200° C. under an argon atmosphere to deposit copper particles in situ;

[0014] 4) Immersing the copper-loaded carbon nanotube sponge in a thermoplastic polyurethane / dimethylformamide solution, and performing vacuum-assisted impregnation to allow the thermoplastic polyurethane to fully fill the pores, thereby forming a composite material.

[0015] Furthermore, the copper particles are evenly distributed in the carbon nanotube sponge, and the thickness of the composite material is 10-500 μm, and the electrical conductivity exceeds 2×10 4 S / m.

[0016] Furthermore, the composite material has a thickness of about 100 μm.

[0017] Furthermore, the electromagnetic shielding effectiveness of the composite material in the 5-40 GHz frequency band is higher than 45 dB; the electromagnetic shielding effectiveness of the composite material in the 0.2-1.6 THz frequency band is higher than 60 dB.

[0018] Furthermore, the composite material has an electromagnetic shielding effectiveness of 57.8 dB in the 5-40 GHz frequency band and an electromagnetic shielding effectiveness of more than 60 dB in the 0.2-1.6 THz frequency band.

[0019] Furthermore, the composite material can be heated to a temperature of 160° C. at a voltage of 3.5 V, with a heating rate exceeding 10° C. / s.

[0020] Furthermore, the composite material has excellent flexibility and deformation tolerance, with performance degradation of less than 10% under extreme deformation conditions; and can maintain stable heating performance under conditions of a bending radius of ≤1 mm.

[0021] Furthermore, in step 2), the mixing ratio of copper formate tetrahydrate and 2-amino-2-methyl-1-propanol is 1:2.

[0022] Furthermore, in step 3), the pretreated CNT sponge is completely immersed in the Cu-MOD solution for 10 minutes; and the annealing time of the in-situ deposited copper particles is 20 minutes.

[0023] Furthermore, in step 4), the mass fraction of the thermoplastic polyurethane / dimethylformamide solution is 1%.

[0024] In addition, the present invention also discloses an application of a composite material prepared by the preparation method of the carbon nanotube sponge / copper / thermoplastic polyurethane composite material.

[0025] Furthermore, the composite material can be used in the field of electromagnetic shielding or electric heating.

[0026] Including 5G communication equipment, aerospace electronic protection and low-voltage driven heating devices.

[0027] The composite material can be used in wearable smart clothing, medical thermal therapy patches, flexible sensors and high-efficiency energy storage devices.

[0028] Furthermore, the preparation method of the composite material is environmentally friendly and controllable, adopts an argon protection annealing process to avoid copper oxidation, and uses a solution impregnation method that is suitable for large-scale production.

[0029] Compared with traditional CNT-based materials and metal composite processes, this invention has the following significant advantages:

[0030] 1) Significant improvement in electrical conductivity: Through in-situ deposition of copper particles by MOD method, the electrical conductivity of Cu-2.0@CNT reaches 22051S / m, which is more than 20 times higher than that of pure CNT sponge (1096S / m) and significantly better than that of CNT / Ag film reported in the literature (about 10 4 S / m).

[0031] 2) Ultra-wideband electromagnetic shielding: In the 5-40GHz and 0.2-1.6THz frequency bands, the shielding effectiveness reaches 57.8dB and over 60dB respectively, which has a greater thickness advantage than similar materials (such as CNT / SiC composite materials, with an EMI SE of 66.33dB at a thickness of 0.3mm).

[0032] 3) Low-voltage and high-efficiency heating: Only 3.5V driving voltage is required to achieve a saturation temperature of 160°C. The heating rate (10°C / s) far exceeds that of commercial carbon fiber heating film (3°C / s@12V). It also has excellent flexibility and stability, and the performance degradation after bending is less than 10%.

[0033] 4) The process is environmentally friendly and controllable: The preparation method of the composite material is environmentally friendly and controllable. An argon protection annealing process is used to avoid copper oxidation. The solution impregnation method is low-cost and suitable for large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 A flow chart for composite material preparation, showing the key steps of CNT pretreatment, copper deposition, and TPU compounding;

[0035] Figure 2 a is the SEM image of Cu-2.0@CNT in Example 1, showing that copper particles (3-5 μm) are evenly distributed in the CNT network. Figure 2 b is a high-resolution image of Cu-2.0@CNT in Example 1, showing the close interface between copper and CNT;

[0036] Figure 3 This is the 5-40GHz electromagnetic shielding effectiveness curve, comparing the performance differences of samples with different copper loadings;

[0037] Figure 4 This is the electrothermal response curve of Cu-2.0@CNT in Example 1 at 3.5V, showing a rapid temperature rise over time and cycle stability;

[0038] Figure 5 This is an infrared thermal image of the folded Cu-2.0@CNT in Example 1, demonstrating that the material maintains uniform heating and shielding functions even under extreme deformation.

[0039] Figure 6 This is the electrothermal response curve of Cu-2.0@CNT in Example 1 at different voltages. DETAILED DESCRIPTION

[0040] The present invention will be further described in detail below through specific preferred embodiments in conjunction with the accompanying drawings, but the present invention is not limited to the following embodiments.

[0041] The present invention discloses a preparation method of the above-mentioned carbon nanotube sponge / copper / thermoplastic polyurethane composite material, which covers the full process of carbon nanotube sponge pretreatment, copper precursor solution preparation, in-situ deposition of copper particles, and TPU composite densification. The core steps include argon protection annealing and polymer interface optimization.

[0042] Preparation technology of carbon nanotube sponge / copper / thermoplastic polyurethane composite materials:

[0043] A three-dimensional carbon nanotube sponge with a self-supporting structure was prepared by chemical vapor deposition. Through metal organic deposition and vacuum-assisted impregnation, the conductive network of the carbon nanotube sponge was fixed with copper metal particles and polymer thermoplastic polyurethane (TPU), and a carbon nanotube sponge / copper / thermoplastic polyurethane composite material was successfully prepared.

[0044] The material properties of the carbon nanotube sponge / copper / thermoplastic polyurethane composite material of the present invention are:

[0045] CNT / TPU composites with uniformly distributed copper particles have a thickness of 10-500 μm and an electrical conductivity exceeding 2×10 4 S / m, combining ultra-thinness, flexibility and high conductivity.

[0046] The application scope of the carbon nanotube sponge / copper / thermoplastic polyurethane composite material of the present invention is as follows:

[0047] Electromagnetic shielding fields (such as 5G communication equipment, aerospace electronic protection), low-voltage driven heating devices (such as wearable smart clothing, medical thermotherapy patches), flexible sensors and high-efficiency energy storage devices.

[0048] Outstanding performance in electromagnetic shielding and electric heating applications:

[0049] The successful in-situ deposition of copper particles and the introduction of thermoplastic polyurethane significantly enhanced the conductive network within the composite film, while also significantly improving the film's electromagnetic wave absorption loss, demonstrating excellent electromagnetic shielding effectiveness across the wide electromagnetic wave frequency range of 5-40 GHz and 0.2-1.6 THz. We also tested the composite film's electrothermal heating performance. The increased conductivity also resulted in excellent electrothermal heating properties, including superior heating uniformity, heating stability, rapid heating response, and outstanding electrothermal conversion efficiency.

[0050] like Figure 1 The figure shows a flow chart for preparing a composite material, illustrating the key steps of CNT pretreatment, copper deposition, and TPU compounding. The method for preparing a carbon nanotube sponge / copper / thermoplastic polyurethane composite disclosed in the present invention specifically includes the following steps:

[0051] 1) Prepare carbon nanotube sponge by chemical vapor deposition and remove surface impurities by plasma cleaning;

[0052] 2) preparing a copper precursor solution comprising a mixture of copper formate tetrahydrate, 2-amino-2-methyl-1-propanol, and methanol in a ratio of copper formate tetrahydrate to 2-amino-2-methyl-1-propanol of 1:2 to form a Cu-MOD solution having a concentration of 0.1-2.0 mol / L;

[0053] 3) Soaking the pretreated carbon nanotube sponge in the Cu-MOD solution and annealing it at 200° C. in an argon atmosphere to deposit copper particles in situ; the copper particles are evenly distributed in the carbon nanotube sponge.

[0054] 4) Immerse the copper-loaded carbon nanotube sponge in a thermoplastic polyurethane / dimethylformamide solution, and use vacuum-assisted impregnation to fully fill the pores with the thermoplastic polyurethane to form a composite material. The thickness of the composite material is 10-500 μm, and the electrical conductivity exceeds 2×10 4 S / m;

[0055] The electromagnetic shielding effectiveness of the composite material reaches 57.8dB in the 5-40GHz frequency band and exceeds 60dB in the 0.2-1.6THz frequency band; the heating temperature of the composite material can reach 160°C at a voltage of 3.5V, and the heating rate exceeds 10°C / s; the composite material has excellent deformation tolerance, and the performance attenuation under extreme deformation conditions is less than 10%.

[0056] A method for preparing the carbon nanotube sponge / copper / thermoplastic polyurethane composite material comprises the following steps:

[0057] (1) CNT sponge pretreatment:

[0058] Porous carbon nanotube sponge was prepared by chemical vapor deposition (CVD) method, and surface impurities were removed by plasma cleaning (150W, 5 minutes), and hydrophilic oxygen-containing groups were introduced to improve the subsequent solution wettability.

[0059] (2) Preparation of copper precursor solution:

[0060] Copper formate tetrahydrate (Cu(HCOO)2·4H2O), 2-amino-2-methyl-1-propanol (AMP), and methanol are mixed in appropriate proportions and magnetically stirred to form a Cu-MOD solution with a concentration of 0.1-2.0 mol / L. AMP acts as a complexing agent, forming a stable coordination structure with copper ions, ensuring uniform nucleation and growth of copper particles during annealing.

[0061] (3) In-situ deposition of copper particles:

[0062] The pretreated CNT sponge was completely immersed in the Cu-MOD solution for 10 minutes, then transferred to a tube furnace and annealed at 200°C for 20 minutes under an argon atmosphere. During this process, copper formate tetrahydrate thermally decomposed to produce copper, carbon dioxide, and hydrogen.

[0063] (4) TPU composite densification:

[0064] The copper-loaded CNT sponge (Cu@CNT) was immersed in a 1% mass fraction TPU-DMF solution, and the TPU was fully filled in the pores by vacuum-assisted impregnation. After drying, a dense and flexible film with a thickness of about 100 μm was formed (named Cu-x@CNT, where x represents the concentration of the copper precursor solution).

[0065] The specific innovative features of the present invention can be expressed as follows:

[0066] 1. In-situ metal deposition technology: Metal organic deposition (MOD) is used to generate uniformly distributed copper particles in situ in the CNT sponge. Combined with an argon gas protection process, copper oxidation is inhibited, significantly enhancing the conductivity and interfacial bonding strength of the CNT network.

[0067] 2. Polymer interface optimization: Thermoplastic polyurethane (TPU) is introduced to densify and fix the conductive network, improving the mechanical properties and flexible stability of the material, making it able to withstand extreme deformation (such as folding).

[0068] 3. Multifunctional integrated design: A single material simultaneously achieves ultra-wideband electromagnetic shielding (covering 5GHz to 1.6THz), low-voltage driven rapid heating (up to 160°C at 3.5V), and excellent deformation tolerance, meeting the comprehensive needs of next-generation flexible electronic devices.

[0069] The following are examples of preparing the carbon nanotube sponge / copper / thermoplastic polyurethane composite material of the present invention.

[0070] Example 1: Preparation of Cu-2.0@CNT

[0071] 1. CNT sponge pretreatment:

[0072] The carbon nanotube sponge prepared by CVD method was cut into 5 cm × 5 cm blocks, placed in a plasma cleaning machine, and treated at a power of 150 W for 5 minutes to obtain a hydrophilic surface.

[0073] 2. Preparation of copper precursor solution:

[0074] Weigh 2.0 mol of copper formate tetrahydrate and slowly add it to a methanol solution containing 4.0 mol of AMP. Stir magnetically for 20 minutes and dilute to 50 mL to obtain a 2.0 mol / L Cu-MOD solution.

[0075] 3. In-situ deposition of copper particles:

[0076] The pretreated CNT sponge was immersed in the Cu-MOD solution for 10 minutes, taken out and fixed in a fixture, placed in a tube furnace, introduced with argon gas and annealed at 200°C for 20 minutes to prepare a Cu@CNT composite material.

[0077] 4.TPU composite densification:

[0078] Cu@CNT was immersed in 1% TPU-DMF solution, vacuum-assisted impregnation for 30 minutes, and dried at 80°C to obtain a flexible film with a thickness of about 100 μm.

[0079] Figure 2 middle Figure 2 a and Figure 2 Scanning electron microscopy observation of b shows that the Cu particles in the Cu-2.0@CNT composite material of this embodiment are evenly distributed in the carbon nanotube sponge and the carbon nanotube sponge is entirely wrapped by the polymer TPU.

[0080] Figure 3 The electromagnetic shielding effectiveness curve in FIG shows that the Cu-2.0@CNT in this embodiment exhibits a total electromagnetic shielding effectiveness of up to 57.8 dB in the ultra-wide frequency band of 5-40 GHz.

[0081] Figure 4 The temperature curves and infrared photos in the figure show that the Cu-2.0@CNT in this embodiment can maintain long-term heating stability and uniformity at a voltage of 3.5 V, and can still maintain stable switching cyclicity after long-term heating for 3600 s.

[0082] Figure 5 The digital photos and corresponding infrared photos in the figure show that the Cu-2.0@CNT composite material in this embodiment has excellent flexible bending and heating properties.

[0083] Example 2: Preparation of Cu-1.0@CNT

[0084] 1. CNT sponge pretreatment:

[0085] The carbon nanotube sponge prepared by CVD method was cut into 5 cm × 5 cm blocks, placed in a plasma cleaning machine, and treated at a power of 150 W for 5 minutes to obtain a hydrophilic surface.

[0086] 2. Preparation of copper precursor solution:

[0087] Weigh 1.0 mol of copper formate tetrahydrate and slowly add it to a methanol solution containing 2.0 mol of AMP. Stir magnetically for 20 minutes and dilute to 50 mL to obtain a 1.0 mol / L Cu-MOD solution.

[0088] 3. In-situ deposition of copper particles:

[0089] The pretreated CNT sponge was immersed in the Cu-MOD solution for 10 minutes, taken out and fixed in a fixture, placed in a tube furnace, introduced with argon gas and annealed at 200°C for 20 minutes to prepare a Cu@CNT composite material.

[0090] 4.TPU composite densification:

[0091] Cu@CNT was immersed in 1% TPU-DMF solution, vacuum-assisted impregnation for 30 minutes, and dried at 80°C to obtain a flexible film with a thickness of about 100 μm.

[0092] Figure 3 The electromagnetic shielding effectiveness curve in FIG shows that the Cu-1.0@CNT in this embodiment exhibits a total electromagnetic shielding effectiveness of up to 45.6 dB in the ultra-wide frequency band of 5-40 GHz.

[0093] Example 3: Preparation of Cu-0.5@CNT

[0094] 1. CNT sponge pretreatment:

[0095] The carbon nanotube sponge prepared by CVD method was cut into 5 cm × 5 cm blocks, placed in a plasma cleaning machine, and treated at a power of 150 W for 5 minutes to obtain a hydrophilic surface.

[0096] 2. Preparation of copper precursor solution:

[0097] Weigh 0.5 mol of copper formate tetrahydrate and slowly add it to a methanol solution containing 1.0 mol of AMP. Stir magnetically for 20 minutes and dilute to 50 mL to obtain a 0.5 mol / L Cu-MOD solution.

[0098] 3. In-situ deposition of copper particles:

[0099] The pretreated CNT sponge was immersed in the Cu-MOD solution for 10 minutes, taken out and fixed in a fixture, placed in a tube furnace, introduced with argon gas and annealed at 200°C for 20 minutes to prepare a Cu@CNT composite material.

[0100] 4.TPU composite densification:

[0101] Cu@CNT was immersed in 1% TPU-DMF solution, vacuum-assisted impregnation for 30 minutes, and dried at 80°C to obtain a flexible film with a thickness of about 100 μm.

[0102] Figure 3 The electromagnetic shielding effectiveness curve in FIG shows that the Cu-0.5@CNT in this embodiment exhibits a total electromagnetic shielding effectiveness of up to 42.9 dB in the ultra-wide frequency band of 5-40 GHz.

[0103] The following are the relevant contents of the efficacy test examples of the composite materials of the embodiments of the present invention:

[0104] 1. Electromagnetic shielding test:

[0105] Test method: A vector network analyzer (Keysight N5227B) was used to test the shielding effectiveness of the material in the 5-40 GHz and 0.2-1.6 THz frequency bands.

[0106] Experimental results: The average shielding effectiveness of Cu-2.0@CNT (thickness 0.1mm) in the 5-40GHz frequency band is 57.8dB, which is more than 150% higher than that of pure CNT sponge (22.6dB); the normalized shielding effectiveness reaches 578dB / mm, which is significantly better than the pure CNT film without copper loading (22.6dB); in the 0.2-1.6THz frequency band, the shielding effectiveness exceeds 60dB, which is significantly better than similar materials such as MXene / CNT composite materials (EMI SE is 23.4dB when the thickness is 1.19mm); it can shield 99.9999% of the incident electromagnetic waves, meeting the protection needs of precision electronic equipment.

[0107] The shielding effectiveness of Cu-2.0@CNT in the X-band (8-12 GHz) was measured using a vector network analyzer. The results showed that the total shielding effectiveness was 54.9 dB, of which the reflection effectiveness accounted for 98.3% and the absorption effectiveness accounted for 1.7%.

[0108] 2. Electric heating cycle test:

[0109] Test method: Use an infrared thermal imager to monitor the temperature change of the material under 1.0-3.5V voltage drive, and test its cycle stability and deformation tolerance.

[0110] Experimental results: Driven by a low voltage of 3.5V, the Cu-2.0@CNT film rapidly heated to 160°C within 15 seconds, with a heating rate exceeding 10°C / second; after folding into the shape of a paper airplane (bending radius ≤1mm), it still maintained stable heating performance, demonstrating its excellent flexibility and reliability.

[0111] The film was continuously driven and heated at a voltage of 3.5V for 1 hour, and infrared thermal imaging showed that the temperature was stable at 160±2℃; then 5 switching cycles were performed, and each cycle reached the target temperature within 15 seconds without any performance degradation.

[0112] Under 3.5V drive, the saturation temperature of Cu-2.0@CNT reaches 160℃, with a heating rate of 10℃ / s, which is more than 60% higher than the efficiency of SWCNT film reported in the literature (100℃ under 6V drive).

[0113] This invention utilizes metal organic deposition and vacuum-assisted impregnation methods to achieve a carbon nanotube sponge conductive network, bridged by copper metal particles and anchored by a polymer called thermoplastic polyurethane (TPU), significantly improving its electrical conductivity. By strengthening the conductive network within the composite film, the film's absorption loss to electromagnetic waves is also significantly improved, demonstrating excellent electromagnetic shielding effectiveness across the ultra-wide electromagnetic frequency bands of 5-40 GHz and 0.2-1.6 THz.

[0114] At the same time, the present invention also tested the performance of the composite film in electrothermal heating. The improvement in electrical conductivity also enabled the composite film to exhibit excellent electrothermal heating performance, including excellent heating uniformity, heating stability, rapid heating response and outstanding electrothermal conversion efficiency.

[0115] The following are two specific examples of applications of carbon nanotube sponge / copper / thermoplastic polyurethane composites:

[0116] Application Example 1: Integrated Heating Element for Wearable Smart Clothing

[0117] With the development of wearable technology, the demand for smart clothing is increasing. Heating functions that provide comfortable warmth in cold weather are a key market need. This example demonstrates how Cu@CNT composites can be used as integrated heating elements in wearable smart clothing.

[0118] Material preparation: Preparation of Cu@CNT composite material: Prepare Cu-2.0@CNT composite material according to the method of Example 1.

[0119] The integration steps are as follows:

[0120] Heating element design: The Cu@CNT composite material is cut and designed into the form of a heating element (e.g., a mesh structure) to improve the uniformity of heat distribution.

[0121] Electrical Connections: Connect conductive traces to both ends of the heating element to ensure it can be connected to a power source.

[0122] Performance test: Under a voltage of 2.0V, the heating element is tested to heat up to 67℃ within 15 seconds and maintain stable heating performance. The heating element is embedded in the smart clothing and worn to evaluate its comfort and heating effect. Figure 6 As shown, Figure 6 The temperature curve in FIG shows that the Cu-2.0@CNT in this embodiment can reach different saturation temperatures under different applied voltages.

[0123] Application effect: This smart clothing can quickly heat up in a cold environment, providing a comfortable wearing experience, and due to the flexible properties of the composite material, the clothing will not be restricted when worn.

[0124] Application Example 2: Application of medical hyperthermia patch

[0125] Hyperthermia is a common physical therapy method widely used to relieve pain and promote blood circulation. This example demonstrates how a Cu@CNT composite material can be used in a medical hyperthermia patch.

[0126] Preparation of Cu@CNT composite material: Cu-2.0@CNT composite material was prepared according to the method of Example 1.

[0127] Preparation of medical patch substrate: TPU film with good biocompatibility is selected as the substrate of the patch.

[0128] Thermal therapy patch design: The Cu@CNT composite material is cut into shapes suitable for human body parts (such as knees, back, etc.) and designed into a reusable thermal therapy patch.

[0129] Power connection: Conductive connectors are provided on the edge of the patch to facilitate connection with a rechargeable power source.

[0130] Performance testing: At 2V, the patch rapidly heated to 67°C within 15 seconds and maintained stable heating performance. Clinical testing was conducted to evaluate its effectiveness in relieving muscle pain and promoting blood circulation.

[0131] Application effect: This medical hyperthermia patch can quickly heat up and provide continuous hyperthermia effect, has good biocompatibility and comfort, and is suitable for use in home and medical environments.

[0132] The above two application examples demonstrate the specific applications of carbon nanotube sponge / copper / thermoplastic polyurethane composites in wearable smart clothing and medical hyperthermia patches, fully demonstrating their excellent electrothermal performance and flexibility.

[0133] In addition, the carbon nanotube sponge / copper / thermoplastic polyurethane composite material of the present invention can also have the following applications.

[0134] 1. Shielding of high-frequency electronic equipment: As an ultra-thin shielding layer for 5G communication base stations and millimeter-wave radars, it effectively suppresses high-frequency electromagnetic interference.

[0135] 2. Wearable smart heating: Integrated into flexible clothing or protective gear, it achieves rapid heating at a safe 3.5V voltage, suitable for protection in extremely cold environments or medical hyperthermia therapy.

[0136] 3. Aerospace protection: As a lightweight multifunctional coating, it is used in satellites, drones and other equipment, and has both electromagnetic shielding and thermal management functions.

[0137] 4. Medical precision hot compress: Develop low-voltage driven patch-type hot compress devices to relieve chronic diseases such as arthritis and muscle pain.

[0138] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A method for preparing a carbon nanotube sponge / copper / thermoplastic polyurethane composite material, characterized in that: The following steps are involved: 1) Prepare carbon nanotube sponge by chemical vapor deposition and remove surface impurities by plasma cleaning; 2) preparing a copper precursor solution comprising a mixture of copper formate tetrahydrate, 2-amino-2-methyl-1-propanol, and methanol to form a Cu-MOD solution with a concentration of 0.1-2.0 mol / L; 3) soaking the pretreated carbon nanotube sponge in the Cu-MOD solution and annealing it at 200° C. under an argon atmosphere to deposit copper particles in situ; 4) Immersing the copper-loaded carbon nanotube sponge in a thermoplastic polyurethane / dimethylformamide solution, and performing vacuum-assisted impregnation to allow the thermoplastic polyurethane to fully fill the pores, thereby forming a composite material.

2. The preparation method according to claim 1, wherein: The copper particles are evenly distributed in the carbon nanotube sponge, and the thickness of the composite material is 10-500 μm, and the electrical conductivity exceeds 2×10 4 S / m.

3. The preparation method according to claim 2, wherein: The thickness of the composite material is about 100 μm.

4. The preparation method according to claim 1, wherein: The electromagnetic shielding effectiveness of the composite material in the 5-40 GHz frequency band is higher than 45 dB; the electromagnetic shielding effectiveness of the composite material in the 0.2-1.6 THz frequency band is higher than 60 dB.

5. The preparation method according to claim 1, wherein: In the step 2), the mixing ratio of the copper formate tetrahydrate and 2-amino-2-methyl-1-propanol is 1:

2.

6. The preparation method according to claim 1, wherein: In the step 3), the pretreated CNT sponge is completely immersed in the Cu-MOD solution for 10 minutes; The annealing time of the in-situ deposited copper particles is 20 minutes.

7. The preparation method according to claim 1, wherein: In the step 4), the mass fraction of the thermoplastic polyurethane / dimethylformamide solution is 1%.

8. Use of the carbon nanotube sponge / copper / thermoplastic polyurethane composite material prepared by the preparation method according to any one of claims 1 to 7, characterized in that: The composite material can be used in the field of electromagnetic shielding or electric heating.

9. Use of the composite material according to claim 8, characterized in that: The electromagnetic shielding field includes but is not limited to 5G communication equipment and aerospace electronic protection.

10. Use of the composite material according to claim 8, characterized in that: The field of electrothermal heating includes but is not limited to low voltage driven heating devices; The low-voltage driven heating device includes but is not limited to wearable smart clothing, medical thermal therapy patches, flexible sensors and high-efficiency energy storage devices.

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