A carbon nanotube / graphene / magnetic MOF composite broadband shielding cable and its preparation method

Abstract

The invention discloses a carbon nanotube / graphene / magnetic MOF composite broadband shielded cable and a preparation method thereof. The invention comprises the following steps: uniformly dispersing carbon nanotube powder in a mixture of hydrochloric acid and hydrogen peroxide, heating the mixture in a water bath, and pretreating the carbon nanotube powder, wherein the volume ratio of the hydrochloric acid solution to the hydrogen peroxide is 0.5-4:1-6; uniformly dispersing the pretreated carbon nanotubes in water to obtain a carbon nanotube aqueous dispersion; mixing magnetic metal MOF powder, the carbon nanotube aqueous dispersion, and a graphene oxide dispersion in proportion to obtain a spinning dispersion, wherein the magnetic metal MOF is selected from a monometallic MOF, a bimetallic MOF, or a trimetallic MOF selected from iron, cobalt, and nickel; electrostatically spinning, wet spinning, or fiber coating the mixed dispersion to obtain carbon nanotube / graphene / magnetic MOF composite fibers, and high-temperature carbonizing the composite fibers; and wrapping a fiber fabric obtained by weaving the high-temperature carbonized composite fibers around a conductor to prepare the broadband shielded cable.

Description

Technical Field

[0001] The present invention belongs to the technical field of composite materials, and in particular relates to a carbon nanotube / graphene / magnetic MOF composite broadband shielded cable and a preparation method thereof. Background Art

[0002] The statements herein merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] With the rapid development of modern electronic technology, electromagnetic compatibility and electromagnetic interference (EMI) issues caused by large amounts of electromagnetic waves in precision instruments and electronic circuits have attracted widespread attention. To ensure the transmission performance of electronic devices and components in systems such as the power industry, electronic communications, rail transportation, and automotive and aviation systems in EMI environments, there is an urgent need to design electromagnetic shielding cables that are lightweight, ultra-thin, efficient, durable, broadband, and have excellent mechanical strength and flexibility.

[0004] Traditional metal-based shielded cables have disadvantages such as high density, complex preparation process, easy corrosion, and narrow shielding band. Carbon materials such as carbon nanotubes and graphene have the advantages of low cost, low density, large aspect ratio, excellent mechanical properties and chemical stability, as well as excellent conductivity, and can be widely used in electromagnetic shielding. However, the disordered entanglement and agglomeration of nanoparticles caused by the inert surface of carbon materials lead to large contact resistance in the constructed macrostructure. The relevant solutions are only in the laboratory research stage, and it is difficult to achieve effective compounding of one-dimensional carbon nanotubes and two-dimensional graphene and efficient and large-scale preparation of composite materials. In addition, the multi-band application of electronic equipment also puts higher requirements on the broadband shielding effectiveness of shielded cables. Existing research is difficult to meet the above requirements at the same time. Summary of the Invention

[0005] In view of the shortcomings of the existing technology, the purpose of the present invention is to provide a carbon nanotube / graphene / magnetic MOF composite broadband shielded cable and a preparation method thereof. The carbon nanotube / graphene / magnetic MOF composite broadband shielded cable provided by the present invention has good mechanical strength, flexibility, chemical stability, scalable production capacity and electromagnetic shielding performance.

[0006] In order to achieve the above object, the present invention is implemented through the following technical solutions:

[0007] In a first aspect, the present invention provides a method for preparing a carbon nanotube / graphene / magnetic MOF composite broadband shielded cable, comprising the following steps:

[0008] The carbon nanotube powder is uniformly dispersed in a mixture of hydrochloric acid and hydrogen peroxide, and heated in a water bath to pretreat the carbon nanotube powder. The concentration of the hydrochloric acid solution is 4-7 mol / L, the volume ratio of the hydrochloric acid solution to the hydrogen peroxide is 0.5-4:1-6, the water bath heating temperature is 55-80°C, and the water bath heating time is 3-5 hours.

[0009] uniformly dispersing the pretreated carbon nanotubes in water to obtain a carbon nanotube aqueous dispersion;

[0010] Mixing a magnetic metal MOF powder, a carbon nanotube aqueous dispersion, and a graphene oxide dispersion in proportion to obtain a mixed dispersion, wherein the magnetic metal MOF is selected from a single metal MOF, a bimetallic MOF, or a trimetallic MOF among iron, cobalt, and nickel;

[0011] The mixed dispersion is subjected to electrospinning, wet spinning or fiber coating treatment to obtain carbon nanotube / graphene / magnetic MOF composite fibers, and the composite fibers are carbonized at high temperature;

[0012] The fiber fabric obtained by weaving the high-temperature carbonized composite fibers is wrapped around the outside of the conductor to prepare a composite broadband shielded cable.

[0013] In a second aspect, the present invention provides a carbon nanotube / graphene / magnetic MOF composite broadband shielded cable, which is prepared by the preparation method.

[0014] The beneficial effects achieved by one or more embodiments of the present invention are as follows:

[0015] Treating the chemically inert carbon nanotube powder with hydrochloric acid and hydrogen peroxide effectively removes some metal catalysts present in the carbon nanotube preparation process, such as iron, cobalt, and nickel. It also functionalizes the carbon nanotube surface, generating a chemical reaction on the surface to form hydrophilic groups such as hydroxyl or carboxyl groups.

[0016] Leveraging the inherently high electrical conductivity of one-dimensional carbon nanotubes and the abundant hydrophilic groups on the surface of two-dimensional graphene oxide, which exhibits high electrical conductivity after subsequent high-temperature reduction treatment, a highly efficient one-dimensional / two-dimensional conductive network is constructed. The introduction of magnetic MOF effectively increases magnetic loss and enhances the electromagnetic loss mechanism, resulting in a highly conductive composite fiber that exhibits improved electromagnetic shielding performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0018] Figure 1This is a test image of the carbon nanotube / graphene / magnetic MOF composite fiber provided in Example 1;

[0019] Figure 2 This is a test image of the carbon nanotube / graphene / magnetic MOF composite fiber provided in Example 1;

[0020] Figure 3 This is a graph showing the mechanical properties of the carbon nanotube / graphene / magnetic MOF composite fiber provided in Example 1;

[0021] Figure 4 A graph showing the electromagnetic shielding performance test results of the carbon nanotube / graphene / magnetic MOF composite broadband shielded cable provided in Example 4;

[0022] Figure 5 This is a diagram of the electromagnetic shielding mechanism of the carbon nanotube / graphene / magnetic MOF composite broadband shielded cable provided in Example 5. DETAILED DESCRIPTION

[0023] It should be noted that the following detailed description is illustrative and is 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 meaning as commonly understood by those skilled in the art to which the present invention belongs.

[0024] In a first aspect, the present invention provides a method for preparing a carbon nanotube / graphene / magnetic MOF composite broadband shielded cable, comprising the following steps:

[0025] The carbon nanotube powder is uniformly dispersed in a mixture of hydrochloric acid and hydrogen peroxide, and heated in a water bath to pretreat the carbon nanotube powder. The concentration of the hydrochloric acid solution is 4-7 mol / L, the volume ratio of the hydrochloric acid solution to the hydrogen peroxide is 0.5-4:1-6, the water bath heating temperature is 55-80°C, and the water bath heating time is 3-5 hours.

[0026] uniformly dispersing the pretreated carbon nanotubes in water to obtain a carbon nanotube aqueous dispersion;

[0027] Mixing a magnetic metal MOF powder, a carbon nanotube aqueous dispersion, and a graphene oxide dispersion in proportion to obtain a mixed dispersion, wherein the magnetic metal MOF is selected from a single metal MOF, a bimetallic MOF, or a trimetallic MOF among iron, cobalt, and nickel;

[0028] The mixed dispersion is subjected to electrospinning, wet spinning, or fiber coating treatment to obtain carbon nanotube / graphene / magnetic MOF composite fibers, and the composite fibers are carbonized at high temperature;

[0029] The fiber fabric obtained by weaving the high-temperature carbonized composite fibers is wrapped around the outside of the conductor to prepare a wide-screen shielded cable.

[0030] The purpose of water bath heating is to accelerate the pretreatment speed of carbon nanotubes by hydrochloric acid and hydrogen peroxide.

[0031] Leveraging the inherently high electrical conductivity of one-dimensional carbon nanotubes and the abundant hydrophilic groups on the surface of two-dimensional graphene oxide, which exhibits high electrical conductivity after subsequent high-temperature reduction treatment, a highly efficient one-dimensional / two-dimensional conductive network is formed. The introduction of magnetic MOF effectively increases magnetic loss and enhances the electromagnetic loss mechanism, resulting in a highly conductive composite fiber that exhibits improved electromagnetic shielding performance.

[0032] The high-temperature carbonization-reduction treatment mainly involves carbon reduction of graphene oxide to obtain graphene with higher conductivity; the magnetic MOF precursor undergoes a carbonization process to obtain magnetic metal particles / carbon nanocomposites; and finally, carbon nanotubes / graphene / magnetic MOF composite fibers are obtained.

[0033] In some embodiments, the water bath heating temperature is 55-65° C., the heating time is 3.5-4.5 h, and stirring is continued during the water bath heating process.

[0034] In some embodiments, the carbon nanotubes are single-walled carbon nanotubes, double-walled carbon nanotubes, or multi-walled carbon nanotubes, preferably single-walled carbon nanotubes. Single-walled carbon nanotubes have better electrical conductivity. Compared to double-walled or multi-walled carbon nanotubes, which have defects between their layers, single-walled carbon nanotubes have a narrower diameter distribution, fewer defects, greater uniformity, and higher electrical conductivity.

[0035] In some embodiments, the preparation methods of the carbon nanotube / graphene / magnetic MOF composite fibers include electrospinning, wet spinning, or fiber coating; researchers in this profession can choose methods to prepare carbon nanotube / graphene / magnetic MOF fibers or films, etc., but all are within the scope of protection of this patent.

[0036] The magnetic metal MOF is a cobalt MOF. Magnetic metals mainly include iron, cobalt, and nickel. The products obtained by carbonizing iron MOF at different temperatures have a relatively complex composition. Compared with cobalt and nickel, cobalt has a higher Curie temperature, better ductility, and stronger magnetism.

[0037] In some embodiments, the mass ratio of magnetic metal MOF powder, carbon nanotube aqueous dispersion, and graphene oxide dispersion is: 0.1-5.0: 2-55: 2-55;

[0038] The mass percentage of carbon nanotubes in the carbon nanotube aqueous dispersion is 0.5-10wt%;

[0039] The mass percentage of graphene oxide in the graphene oxide dispersion is 0.5-10wt%.

[0040] In some embodiments, the graphene oxide dispersion is prepared by:

[0041] Add graphite powder to a container containing concentrated sulfuric acid solution, place the beaker in an ice-water bath with magnetic stirring, and add potassium permanganate in portions. The mass ratio of graphite to potassium permanganate is 0.5-3:3-18.

[0042] Then transfer the above container to a 45-55°C water bath and react for 8-12 hours;

[0043] Then place the container in an ice water bath and add hydrogen peroxide while stirring until the solution turns golden yellow;

[0044] The bottom precipitate was filtered and washed with deionized water until neutral;

[0045] Finally, the resulting graphene oxide is dispersed in water and subjected to ultrasonic and oscillation to obtain an aqueous graphene oxide dispersion. Using an oscillator to exfoliate and delaminate the graphene oxide dispersion helps to obtain more uniform single layers and larger graphene oxide sheets.

[0046] In some embodiments, the diameter of the fiber is selected from one of 1.65 mm, 1.55 mm, 1.36 mm, 1.2 mm, 1.12 mm, 0.84 mm, 0.7 mm, 0.6 mm, 0.51 mm, 0.41 mm, 0.34 mm, 0.3 mm, 0.26 mm, 0.24 mm, 0.21 mm, 0.16 mm, 0.11 mm, or 0.06 mm.

[0047] Preferably, the diameter of the fiber is selected to be 0.3 mm.

[0048] In some embodiments, the step of washing and drying the prepared composite fiber is further included, wherein the washing liquid is water or ethanol;

[0049] The drying temperature is 45-55°C and the drying time is 1.5-2.5h.

[0050] In some embodiments, the high-temperature carbonization temperature is 550-650° C., the carbonization time is 1.5-2.5 hours, and the carbonization atmosphere is argon.

[0051] In the second aspect, the present invention provides a carbon nanotube / graphene / magnetic MOF composite broadband shielded cable, which is prepared by the preparation method. From the inside to the outside, it consists of a conductor, an internal silicone rubber protective layer, a fiber film shielding layer, a fiber braided shielding layer and an external silicone rubber protective layer, and the fibers in the fiber braided shielding layer are the composite fibers.

[0052] The combination of one-dimensional conductive carbon nanotubes, two-dimensional conductive reduced graphene oxide, and magnetic metal cobalt derived from a magnetic MOF facilitates the formation of a rich conductive network and ensures broadband absorption. The synergistic effect of composition and microstructure gives the carbon nanotube / graphene / magnetic MOF composite broadband shielded cable excellent mechanical strength, excellent conductivity, and electromagnetic shielding performance. The preparation method of the present invention is simple and efficient, easily scalable, and has broad application prospects.

[0053] The present invention provides applications of the carbon nanotube / graphene / magnetic MOF composite broadband shielded cable prepared by the preparation method described in the above scheme in the fields of electromagnetic shielding, photothermal conversion, electrothermal conversion, thermal conductive materials, sensing materials, electrode materials, biomedical materials, antibacterial materials, support materials or wearable flexible electronics.

[0054] The middle carbon nanotube / graphene / magnetic MOF composite fiber woven shielding layer wraps the internal wires to shield external electromagnetic radiation and interference; the outer layer is a silicone rubber layer, which is wrapped on the shielding layer to protect the internal shielding layer and the wires from damage by external forces. Silicone resin is selected as the matrix, and the modified particles are mixed with silicone resin, curing agent, and solvent to form a slurry. The silicone resin protective layer is prepared by a casting or coating molding process.

[0055] The carbon nanotube / graphene / magnetic MOF composite broadband shielded cable provided by the present invention, its preparation method and application are described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0056] Example 1

[0057] 2.0 parts by mass of single-walled carbon nanotubes were slowly added to a beaker containing a mixed solution of 30.0 parts by mass of hydrochloric acid (mass concentration of 37 wt%) and 40.0 parts by mass of hydrogen peroxide (mass concentration of 30 wt%). The beaker was then placed in a 60°C water bath and magnetically stirred for 4 hours. The purified reaction product was then transferred to a centrifuge tube, diluted and washed with an appropriate amount of deionized water, and then centrifuged at 6000 rpm for 10 minutes. The solid precipitate was dispersed again in deionized water and the centrifugation operation was repeated until the pH value was approximately 7. The precipitate at the bottom of the centrifuge tube was collected and dried in an oven set at 50°C for 12 hours to obtain purified carbon nanotube powder.

[0058] 0.5 parts by mass of purified carbon nanotube powder was added to 10 parts by mass of deionized water, stirred continuously for 2 hours, and then ultrasonicated for 30 minutes using an ultrasonic cell disruptor to accelerate the dispersion effect and improve the uniformity of the resulting carbon nanotube aqueous dispersion. Finally, the carbon nanotube aqueous dispersion was obtained.

[0059] 2.0 parts by mass of graphite was added to a beaker containing 15.5 parts by mass of concentrated sulfuric acid solution. The beaker was placed in an ice-water bath with magnetic stirring and 10.0 parts by mass of potassium permanganate was added in 10 portions over 30 minutes. The temperature of the solution was monitored in real time by a thermometer throughout the process to ensure that the temperature of the mixed solution did not exceed 10°C.

[0060] Once the reaction stabilizes, transfer the beaker to a 50°C water bath and maintain magnetic stirring for 10 hours. The beaker is then placed in an ice-water bath and stirred while adding an appropriate amount of hydrogen peroxide until the solution turns golden yellow. The resulting precipitate is then filtered, centrifuged, and washed with deionized water until the pH reaches approximately 7, yielding a graphene oxide dispersion.

[0061] Finally, 2.0 parts by mass of the obtained graphene oxide dispersion was dispersed in 4.0 parts by mass of deionized water, ultrasonicated and shaken to obtain an aqueous graphene oxide dispersion, and the solid content of the obtained aqueous graphene oxide dispersion was calculated.

[0062] 1 part by mass of magnetic metal cobalt MOF (MOF-74 (Co)) powder is added to a beaker containing a mixed solution of 30 parts by mass of carbon nanotube aqueous dispersion (solid content of 2 wt%) and 20.5 parts by mass of graphene oxide suspension dispersion (solid content of 2 wt%) and stirred and ultrasonicated until uniform. Through multiple centrifugation, shaking and other processes, a spinning dispersion suitable for spinning with certain fluidity and shear strain is obtained.

[0063] The spinning dispersion was loaded into the syringe pump of a wet spinning machine, and then pressure was applied by an air pump. The spinning dispersion was continuously extruded at a rate of 2.5 mL / h through a syringe pump needle with an inner diameter of 0.3 mm. The extruded fibers entered a 1 wt% calcium sulfate aqueous solution coagulation liquid. As the syringe pump moved in a directional manner, the extruded spinning dispersion became fibers with a specific shape in the coagulation bath.

[0064] After the fibers solidify, they are removed and washed with a deionized water / ethanol mixture. They are then dried in a 50°C oven for 2 hours to obtain carbon nanotube / graphene oxide / magnetic MOF composite fibers. The resulting carbon nanotube / graphene oxide / magnetic MOF composite fibers are then transferred to a tubular furnace for high-temperature carbonization and reduction. Argon is introduced, and the temperature is raised to 600°C at a rate of 2°C / min and maintained for 2 hours. The fibers are then removed from the furnace after cooling to room temperature, yielding the carbon nanotube / graphene / magnetic MOF composite fibers.

[0065] The resulting carbon nanotube / graphene / magnetic MOF composite fibers were braided to create a structure consisting of an inner conductor, an intermediate carbon nanotube / graphene / magnetic MOF composite fiber braided shielding layer, and an outer silicone rubber protective layer. The intermediate carbon nanotube / graphene / magnetic MOF composite fiber braided shielding layer encases the inner conductor, shielding it from external electromagnetic radiation and interference. An outer silicone rubber layer, wrapped around the shielding layer, protects the inner shielding layer and the conductors from external forces. A silicone resin matrix was used, and the modified particles were mixed with the silicone resin, a curing agent, and a solvent to form a slurry. The silicone resin protective layer was then prepared using a casting or coating process. This resulted in a carbon nanotube / graphene / magnetic MOF composite broadband shielded cable.

[0066] The physical photo of the carbon nanotube / graphene / magnetic MOF composite fiber is as follows Figure 1 The carbon nanotube / graphene / magnetic MOF composite fiber has a small diameter (23 μm) and exhibits good flexibility and mechanical strength (the fiber can lift a weight that is 40,000 times its own weight, as shown in Figure 2). Figure 3 as shown) and the potential for continuous, large-scale production.

[0067] Example 2

[0068] 2.0 parts by mass of single-walled carbon nanotubes were slowly added to a beaker containing a mixed solution of 30.0 parts by mass of hydrochloric acid (mass concentration of 37 wt%) and 40.0 parts by mass of hydrogen peroxide (mass concentration of 30 wt%). The beaker was then placed in a 60°C water bath and magnetically stirred for 4 hours. The purified reaction product was then transferred to a centrifuge tube, diluted and washed with an appropriate amount of deionized water, and then centrifuged at 6000 rpm for 10 minutes. The solid precipitate was dispersed again in deionized water and the centrifugation operation was repeated until the pH value was approximately 7. The precipitate at the bottom of the centrifuge tube was collected and dried in an oven set at 50°C for 12 hours to obtain purified carbon nanotube powder.

[0069] 0.5 parts by mass of carbon nanotube powder was added to 15 parts by mass of deionized water, stirred continuously for 2 hours, and then ultrasonicated for 30 minutes using an ultrasonic cell disruptor to accelerate the dispersion effect and improve the uniformity of the resulting carbon nanotube aqueous dispersion. Finally, the carbon nanotube aqueous dispersion was obtained.

[0070] 4.0 parts by mass of graphite was added to a beaker containing 15.5 parts by mass of concentrated sulfuric acid solution. The beaker was placed in an ice-water bath with magnetic stirring and 10.0 parts by mass of potassium permanganate was added in 10 portions over 30 minutes. During the entire process, the solution temperature was monitored in real time using a thermometer to ensure that the temperature of the mixed solution did not exceed 10°C.

[0071] Once the reaction stabilizes, transfer the beaker to a 50°C water bath and maintain magnetic stirring for 10 hours. Then, place the beaker in an ice-water bath and add an appropriate amount of hydrogen peroxide while stirring until the solution turns golden yellow. Filter the precipitate, centrifuge, and wash with deionized water until the pH is close to 7.

[0072] Finally, 2.0 parts by mass of the obtained graphene oxide dispersion was dispersed in 4.0 parts by mass of deionized water, ultrasonicated and shaken to obtain an aqueous graphene oxide dispersion, and the solid content of the obtained aqueous graphene oxide dispersion was calculated.

[0073] 1 part by mass of magnetic metal cobalt MOF (MOF-74 (Co)) powder is added to a beaker containing a mixed solution of 30 parts by mass of carbon nanotube aqueous dispersion (solid content of 2 wt%) and 20.5 parts by mass of graphene oxide suspension dispersion (solid content of 2 wt%) and stirred and ultrasonicated until uniform. Through multiple centrifugation, shaking and other processes, a spinning dispersion suitable for spinning with certain fluidity and shear strain is obtained.

[0074] The spinning dispersion was loaded into the syringe pump of a wet spinning machine, and then pressure was applied by an air pump. The spinning dispersion was continuously extruded at a rate of 1.5 mL / h through a syringe pump needle with an inner diameter of 0.21 mm. The extruded fibers entered a 1 wt% calcium sulfate aqueous solution coagulation liquid. As the syringe pump moved in a directional manner, the extruded spinning dispersion became fibers with a specific shape in the coagulation bath.

[0075] After the fibers are solidified, the solidified fibers are taken out and washed with a deionized water / ethanol mixed solution, and then dried in an oven at 50° C. for 2 hours to obtain carbon nanotube / graphene oxide / magnetic MOF composite fibers.

[0076] The resulting carbon nanotube / graphene oxide / magnetic MOF composite fibers were transferred to a tube furnace for high-temperature carbonization reduction. Argon was introduced and the temperature was raised to 600°C at a rate of 2°C / min and held for 2 hours. The fibers were then removed from the furnace after cooling to room temperature, yielding the carbon nanotube / graphene / magnetic MOF composite fibers.

[0077] The resulting carbon nanotube / graphene / magnetic MOF composite fibers were braided to create a structure consisting of an inner conductor, an intermediate carbon nanotube / graphene / magnetic MOF composite fiber braided shielding layer, and an outer silicone rubber protective layer. The intermediate carbon nanotube / graphene / magnetic MOF composite fiber braided shielding layer encases the inner conductor, shielding it from external electromagnetic radiation and interference. An outer silicone rubber layer, wrapped around the shielding layer, protects the inner shielding layer and the conductors from external forces. A silicone resin matrix was used, and the modified particles were mixed with the silicone resin, a curing agent, and a solvent to form a slurry. The silicone resin protective layer was then prepared using a casting or coating process. This resulted in a carbon nanotube / graphene / magnetic MOF composite broadband shielded cable.

[0078] The carbon nanotube / graphene / magnetic MOF composite fiber has the following advantages over the existing metal copper wire shielded cable: (1) Lightweight carbon nanotubes as the substrate can achieve lower density, which is conducive to the preparation of lightweight shielded cables; (2) Thinner fiber diameter is conducive to reducing the thickness of the shielding layer; (3) The composite fiber can achieve more effective broadband electromagnetic shielding; (4) Excellent corrosion resistance broadens the application range of carbon nanotube-based shielded cables, as shown in Table 1.

[0079] Table 1

[0080]

[0081] Example 3

[0082] 2.0 parts by mass of single-walled carbon nanotubes were slowly added to a beaker containing a mixed solution of 30.0 parts by mass of hydrochloric acid (mass concentration of 37 wt%) and 40.0 parts by mass of hydrogen peroxide (mass concentration of 30 wt%). The beaker was then placed in a 60°C water bath and magnetically stirred for 4 hours. The purified reaction product was then transferred to a centrifuge tube, diluted and washed with an appropriate amount of deionized water, and then centrifuged at 6000 rpm for 10 minutes. The solid precipitate was dispersed again in deionized water and the centrifugation operation was repeated until the pH value was approximately 7. The precipitate at the bottom of the centrifuge tube was collected and dried in an oven set at 50°C for 12 hours to obtain purified carbon nanotube powder.

[0083] 0.5 parts by mass of purified carbon nanotube powder was added to 10 parts by mass of deionized water, stirred continuously for 2 hours, and then ultrasonicated for 30 minutes using an ultrasonic cell disruptor to accelerate the dispersion effect and improve the uniformity of the resulting carbon nanotube aqueous dispersion. Finally, the carbon nanotube aqueous dispersion was obtained.

[0084] 4.0 parts by mass of graphite was added to a beaker containing 15.5 parts by mass of concentrated sulfuric acid solution. The beaker was placed in an ice-water bath with magnetic stirring and 10.0 parts by mass of potassium permanganate was added in 10 portions over 30 minutes. During the entire process, the solution temperature was monitored in real time using a thermometer to ensure that the temperature of the mixed solution did not exceed 10°C.

[0085] Once the reaction stabilizes, transfer the beaker to a 50°C water bath and maintain magnetic stirring for 10 hours. Then, place the beaker in an ice-water bath and add an appropriate amount of hydrogen peroxide while stirring until the solution turns golden yellow. Filter the precipitate, centrifuge, and wash with deionized water until the pH is close to 7.

[0086] Finally, 2.0 parts by mass of the obtained graphene oxide dispersion was dispersed in 2.0 parts by mass of deionized water, ultrasonicated and shaken to obtain an aqueous graphene oxide dispersion, and the solid content of the obtained aqueous graphene oxide dispersion was calculated.

[0087] 1 part by mass of magnetic metal cobalt MOF (MOF-74 (Co)) powder is added to a beaker containing a mixed solution of 20 parts by mass of carbon nanotube aqueous dispersion (solid content of 2 wt%) and 20.5 parts by mass of graphene oxide suspension dispersion (solid content of 2 wt%) and stirred and ultrasonicated until uniform. Through multiple centrifugation, shaking and other processes, a spinning dispersion suitable for spinning with certain fluidity and shear strain is obtained.

[0088] The spinning dispersion was loaded into the syringe pump of a wet spinning machine, and then pressure was applied by an air pump. The spinning dispersion was continuously extruded at a rate of 5.5 mL / h through a syringe pump needle with an inner diameter of 0.51 mm. The extruded fibers entered a 1 wt% calcium sulfate aqueous solution coagulation liquid. As the syringe pump moved in a directional manner, the extruded spinning dispersion became fibers with a specific shape in the coagulation bath.

[0089] After the fibers are solidified, the solidified fibers are taken out and washed with a deionized water / ethanol mixed solution, and then dried in an oven at 50° C. for 2 hours to obtain carbon nanotube / graphene oxide / magnetic MOF composite fibers.

[0090] The resulting carbon nanotube / graphene oxide / magnetic MOF composite fibers were transferred to a tube furnace for high-temperature carbonization reduction. Argon was introduced and the temperature was raised to 600°C at a rate of 2°C / min and held for 2 hours. The fibers were then removed from the furnace after cooling to room temperature, yielding the carbon nanotube / graphene / magnetic MOF composite fibers.

[0091] The resulting carbon nanotube / graphene / magnetic MOF composite fibers were braided to create a structure consisting of an inner conductor, an intermediate carbon nanotube / graphene / magnetic MOF composite fiber braided shielding layer, and an outer silicone rubber protective layer. The intermediate carbon nanotube / graphene / magnetic MOF composite fiber braided shielding layer encases the inner conductor, shielding it from external electromagnetic radiation and interference. An outer silicone rubber layer, wrapped around the shielding layer, protects the inner shielding layer and the conductors from external forces. A silicone resin matrix was used, and the modified particles were mixed with the silicone resin, a curing agent, and a solvent to form a slurry. The silicone resin protective layer was then prepared using a casting or coating process. This resulted in a carbon nanotube / graphene / magnetic MOF composite broadband shielded cable.

[0092] The structure of the carbon nanotube / graphene / magnetic MOF composite broadband shielded cable is shown in FIG. Figure 3 shown.

[0093] Example 4

[0094] 2.0 parts by mass of single-walled carbon nanotubes were slowly added to a beaker containing a mixed solution of 30.0 parts by mass of hydrochloric acid (mass concentration of 37 wt%) and 40.0 parts by mass of hydrogen peroxide (mass concentration of 30 wt%). The beaker was then placed in a 60°C water bath and magnetically stirred for 4 hours. The purified reaction product was then transferred to a centrifuge tube, diluted and washed with an appropriate amount of deionized water, and then centrifuged at 6000 rpm for 10 minutes. The solid precipitate was dispersed again in deionized water and the centrifugation operation was repeated until the pH value was approximately 7. The precipitate at the bottom of the centrifuge tube was collected and dried in an oven set at 50°C for 12 hours to obtain purified carbon nanotube powder.

[0095] 0.5 parts by mass of purified carbon nanotube powder was added to 5 parts by mass of deionized water, stirred continuously for 2 hours, and then ultrasonicated for 30 minutes using an ultrasonic cell disruptor to accelerate the dispersion effect and improve the uniformity of the resulting carbon nanotube aqueous dispersion. Finally, the carbon nanotube aqueous dispersion was obtained.

[0096] 4.0 parts by mass of graphite was added to a beaker containing 15.5 parts by mass of concentrated sulfuric acid solution. The beaker was placed in an ice-water bath with magnetic stirring and 10.0 parts by mass of potassium permanganate was added in 10 portions over 30 minutes. During the entire process, the solution temperature was monitored in real time using a thermometer to ensure that the temperature of the mixed solution did not exceed 10°C.

[0097] Once the reaction stabilizes, transfer the beaker to a 50°C water bath and maintain magnetic stirring for 10 hours. Then, place the beaker in an ice-water bath and add an appropriate amount of hydrogen peroxide while stirring until the solution turns golden yellow. Filter the precipitate, centrifuge, and wash with deionized water until the pH is close to 7.

[0098] Finally, 2.0 parts by mass of the obtained graphene oxide dispersion was dispersed in 4.0 parts by mass of deionized water, ultrasonicated and shaken to obtain an aqueous graphene oxide dispersion, and the solid content of the obtained aqueous graphene oxide dispersion was calculated.

[0099] 4 parts by mass of magnetic metal cobalt MOF (MOF-74 (Co)) powder was added to a beaker containing a mixed solution of 40 parts by mass of carbon nanotube aqueous dispersion (solid content of 2 wt%) and 20.5 parts by mass of graphene oxide suspension dispersion (solid content of 2 wt%) and stirred and ultrasonicated until uniform. Through multiple centrifugation, shaking and other processes, a spinning dispersion suitable for spinning with certain fluidity and shear strain was obtained.

[0100] The spinning dispersion was loaded into the syringe pump of a wet spinning machine, and then pressure was applied by an air pump. The spinning dispersion was continuously extruded at a rate of 8.5 mL / h through a syringe pump needle with an inner diameter of 0.7 mm. The extruded fibers entered a 1 wt% calcium sulfate aqueous solution coagulation liquid. As the syringe pump moved in a directional manner, the extruded spinning dispersion became fibers with a specific shape in the coagulation bath.

[0101] After the fibers are solidified, the solidified fibers are taken out and washed with a deionized water / ethanol mixed solution, and then dried in an oven at 50° C. for 2 hours to obtain carbon nanotube / graphene oxide / magnetic MOF composite fibers.

[0102] The resulting carbon nanotube / graphene oxide / magnetic MOF composite fibers were transferred to a tube furnace for high-temperature carbonization reduction. Argon was introduced and the temperature was raised to 600°C at a rate of 2°C / min and held for 2 hours. The fibers were then removed from the furnace after cooling to room temperature, yielding the carbon nanotube / graphene / magnetic MOF composite fibers.

[0103] The resulting carbon nanotube / graphene / magnetic MOF composite fibers were braided to create a structure consisting of an inner conductor, an intermediate carbon nanotube / graphene / magnetic MOF composite fiber braided shielding layer, and an outer silicone rubber protective layer. The intermediate carbon nanotube / graphene / magnetic MOF composite fiber braided shielding layer encases the inner conductor, shielding it from external electromagnetic radiation and interference. An outer silicone rubber layer, wrapped around the shielding layer, protects the inner shielding layer and the conductors from external forces. A silicone resin matrix was used, and the modified particles were mixed with the silicone resin, a curing agent, and a solvent to form a slurry. The silicone resin protective layer was then prepared using a casting or coating process. This resulted in a carbon nanotube / graphene / magnetic MOF composite broadband shielded cable.

[0104] The electromagnetic shielding performance test results of the carbon nanotube / graphene / magnetic MOF composite broadband shielded cable are shown in the figure below: Figure 4As shown in the figure, the electromagnetic shielding effectiveness of the carbon nanotube / graphene / magnetic MOF composite broadband shielded cable can reach 88dB when the thickness of the carbon nanotube / graphene / magnetic MOF composite fiber shielding layer is 24μm.

[0105] Example 5

[0106] 2.0 parts by mass of single-walled carbon nanotubes were slowly added to a beaker containing a mixed solution of 30.0 parts by mass of hydrochloric acid (mass concentration of 37 wt%) and 40.0 parts by mass of hydrogen peroxide (mass concentration of 30 wt%). The beaker was then placed in a 60°C water bath and magnetically stirred for 4 hours. The purified reaction product was then transferred to a centrifuge tube, diluted and washed with an appropriate amount of deionized water, and then centrifuged at 6000 rpm for 10 minutes. The solid precipitate was again dispersed in deionized water and the centrifugation operation was repeated until the pH value was approximately 7. The precipitate at the bottom of the centrifuge tube was collected and dried in an oven set at 50°C for 12 hours to obtain purified carbon nanotube powder.

[0107] 0.5 parts by mass of carbon nanotube powder was added to 10 parts by mass of deionized water, stirred continuously for 2 hours, and then ultrasonicated for 30 minutes using an ultrasonic cell disruptor to accelerate the dispersion effect and improve the uniformity of the resulting carbon nanotube aqueous dispersion. Finally, the carbon nanotube aqueous dispersion was obtained.

[0108] 4.0 parts by mass of graphite was added to a beaker containing 15.5 parts by mass of concentrated sulfuric acid solution. The beaker was placed in an ice-water bath with magnetic stirring and 10.0 parts by mass of potassium permanganate was added in 10 portions over 30 minutes. During the entire process, the solution temperature was monitored in real time using a thermometer to ensure that the temperature of the mixed solution did not exceed 10°C.

[0109] Once the reaction stabilizes, transfer the beaker to a 50°C water bath and maintain magnetic stirring for 10 hours. Then, place the beaker in an ice-water bath and add an appropriate amount of hydrogen peroxide while stirring until the solution turns golden yellow. Filter the precipitate, centrifuge, and wash with deionized water until the pH is close to 7.

[0110] Finally, 2.0 parts by mass of the obtained graphene oxide dispersion was dispersed in 4.0 parts by mass of deionized water, ultrasonicated and shaken to obtain an aqueous graphene oxide dispersion, and the solid content of the obtained aqueous graphene oxide dispersion was calculated.

[0111] 5 parts by mass of magnetic metal cobalt MOF (MOF-74 (Co)) powder was added to a beaker containing a mixed solution of 20 parts by mass of carbon nanotube aqueous dispersion (solid content of 2 wt%) and 20 parts by mass of graphene oxide suspension dispersion (solid content of 2 wt%) and stirred and ultrasonicated until uniform. Through multiple centrifugation, shaking and other processes, a spinning dispersion suitable for spinning with certain fluidity and shear strain was obtained.

[0112] The spinning dispersion was loaded into the syringe pump of a wet spinning machine, and then pressure was applied by an air pump. The spinning dispersion was continuously extruded at a rate of 0.6 mL / h through a syringe pump needle with an inner diameter of 0.11 mm. The extruded fibers entered a 1 wt% calcium sulfate aqueous solution coagulation liquid. As the syringe pump moved in a directional manner, the extruded spinning dispersion became fibers with a specific shape in the coagulation bath.

[0113] After the fibers solidify, they are removed and washed with a deionized water / ethanol mixture. They are then dried in a 50°C oven for 2 hours to obtain carbon nanotube / graphene oxide / magnetic MOF composite fibers. The resulting carbon nanotube / graphene oxide / magnetic MOF composite fibers are then transferred to a tubular furnace for high-temperature carbonization and reduction. Argon is introduced, and the temperature is raised to 600°C at a rate of 2°C / min and maintained for 2 hours. The fibers are then removed from the furnace after cooling to room temperature, yielding the carbon nanotube / graphene / magnetic MOF composite fibers.

[0114] The resulting carbon nanotube / graphene / magnetic MOF composite fibers were braided to create a structure consisting of an inner conductor, an intermediate carbon nanotube / graphene / magnetic MOF composite fiber braided shielding layer, and an outer silicone rubber protective layer. The intermediate carbon nanotube / graphene / magnetic MOF composite fiber braided shielding layer encases the inner conductor, shielding it from external electromagnetic radiation and interference. An outer silicone rubber layer, wrapped around the shielding layer, protects the inner shielding layer and the conductors from external forces. A silicone resin matrix was used. The modified particles were mixed with the silicone resin, a curing agent, and a solvent to form a slurry. The silicone resin protective layer was then prepared using a casting or coating process. This resulted in a carbon nanotube / graphene / magnetic MOF composite broadband shielded cable. When the carbon nanotube / graphene / magnetic MOF composite fiber shielding layer was 24 μm thick, the electromagnetic shielding effectiveness of this cable reached 63 dB.

[0115] The electromagnetic shielding mechanism of the carbon nanotube / graphene / magnetic MOF composite broadband shielded cable is shown in FIG. Figure 5 The synergistic effect of the composition and structure of the material at the microscopic scale affects the shielding performance. The combination of conductive and magnetic materials is conducive to improving the electromagnetic shielding performance and expanding the shielding band over a wide frequency range.

[0116] Example 6

[0117] The difference from Example 5 is that the magnetic cobalt MOF in Example 5 is replaced with a magnetic nickel MOF, and all other parameters are the same as Example 5. A carbon nanotube / graphene / magnetic MOF composite broadband shielded cable is prepared, and the electromagnetic shielding effectiveness can reach 58 dB when the thickness of the carbon nanotube / graphene / magnetic MOF composite fiber shielding layer is 24 μm.

[0118] Example 7

[0119] The difference from Example 5 is that the magnetic cobalt MOF in Example 5 is replaced with a magnetic iron MOF, and all other parameters are the same as those in Example 5. A carbon nanotube / graphene / magnetic MOF composite broadband shielded cable is prepared, and the electromagnetic shielding effectiveness can reach 55 dB when the thickness of the carbon nanotube / graphene / magnetic MOF composite fiber shielding layer is 24 μm.

[0120] Comparative Example 1

[0121] The difference from Example 5 is that the step of treating the single-walled carbon nanotubes with hydrochloric acid and hydrogen peroxide in Example 5 is omitted. All other parameters are the same as in Example 5. A carbon nanotube / graphene / magnetic MOF composite broadband shielded cable was prepared. When the carbon nanotube / graphene / magnetic MOF composite fiber shielding layer had a thickness of 24 μm, the electromagnetic shielding effectiveness reached 51 dB.

[0122] Comparative Example 2

[0123] The difference from Example 5 is that the addition of the magnetic metal cobalt MOF is omitted. All other parameters are the same as in Example 5. A carbon nanotube / graphene / magnetic MOF composite broadband shielded cable was prepared. When the carbon nanotube / graphene / magnetic MOF composite fiber shielding layer had a thickness of 24 μm, the electromagnetic shielding effectiveness reached 44 dB.

[0124] The above examples and comparative examples demonstrate that the carbon nanotube / graphene / magnetic MOF composite broadband shielded cable provided by the present invention exhibits excellent mechanical strength, electrical conductivity, and electromagnetic shielding performance. The preparation method of the present invention is simple and efficient, easily scalable, and has broad application prospects.

[0125] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A method for preparing a carbon nanotube / graphene / magnetic MOF composite broadband shielded cable, characterized in that: The steps include: The carbon nanotube powder is uniformly dispersed in a mixture of hydrochloric acid and hydrogen peroxide, and heated in a water bath to pretreat the carbon nanotube powder. The concentration of the hydrochloric acid solution is 4-7 mol / L, the volume ratio of the hydrochloric acid solution to the hydrogen peroxide is 0.5-4:1-6, the water bath heating temperature is 55-80°C, and the water bath heating time is 3-5 hours. uniformly dispersing the pretreated carbon nanotubes in water to obtain a carbon nanotube aqueous dispersion; The magnetic metal MOF powder, the carbon nanotube aqueous dispersion and the graphene oxide dispersion are mixed in a mass ratio of 0.1-5:2-55:2-55 to obtain a spinning dispersion, wherein the mass percentage of the carbon nanotubes in the carbon nanotube aqueous dispersion is 0.5-10 wt%; the mass percentage of the graphene oxide in the graphene oxide dispersion is 0.5-10 wt%; the magnetic metal MOF is selected from a monometallic MOF, a bimetallic MOF or a trimetallic MOF selected from iron, cobalt and nickel; The mixed dispersion is subjected to electrospinning, wet spinning or fiber coating treatment to obtain carbon nanotube / graphene / magnetic MOF composite fibers, and the composite fibers are carbonized at high temperature; The fiber fabric obtained by weaving the high-temperature carbonized composite fibers is wrapped around the outside of the conductor to prepare a wide-screen shielded cable.

2. The method for preparing the carbon nanotube / graphene / magnetic MOF composite broadband shielded cable according to claim 1, characterized in that: The water bath heating temperature is 55-65°C, the heating time is 3.5-4.5h, and stirring is continuous during the water bath heating process.

3. The method for preparing the carbon nanotube / graphene / magnetic MOF composite broadband shielded cable according to claim 1, characterized in that: The carbon nanotubes are single-walled carbon nanotubes, double-walled carbon nanotubes or multi-walled carbon nanotubes.

4. The method for preparing the carbon nanotube / graphene / magnetic MOF composite broadband shielded cable according to claim 1, characterized in that: The magnetic metal MOF is a cobalt MOF.

5. The method for preparing the carbon nanotube / graphene / magnetic MOF composite broadband shielded cable according to claim 1, characterized in that: The preparation method of graphene oxide dispersion is as follows: Add graphite powder to a container containing concentrated sulfuric acid solution, place the beaker in an ice-water bath with magnetic stirring, and add potassium permanganate in portions. The mass ratio of graphite to potassium permanganate is 0.5-3:3-18. Then transfer the above container to a 45-55°C water bath and react for 8-12 hours; Then place the container in an ice water bath and add hydrogen peroxide while stirring until the solution turns golden yellow; The bottom precipitate was filtered and washed with deionized water until neutral; Finally, the obtained graphene oxide is dispersed in water, ultrasonicated and shaken to obtain a graphene oxide aqueous dispersion.

6. The method for preparing the carbon nanotube / graphene / magnetic MOF composite broadband shielded cable according to claim 1, characterized in that: The diameter of the composite fiber after high-temperature carbonization is selected from one of 1.65 mm, 1.55 mm, 1.36 mm, 1.2 mm, 1.12 mm, 0.84 mm, 0.7 mm, 0.6 mm, 0.51 mm, 0.41 mm, 0.34 mm, 0.3 mm, 0.26 mm, 0.24 mm, 0.21 mm, 0.16 mm, 0.11 mm and 0.06 mm.

7. The method for preparing the carbon nanotube / graphene / magnetic MOF composite broadband shielded cable according to claim 1, characterized in that: The method comprises the steps of washing and drying the prepared composite fiber, wherein the washing liquid is water or ethanol.

8. The method for preparing the carbon nanotube / graphene / magnetic MOF composite broadband shielded cable according to claim 7, characterized in that: The drying temperature is 45-55°C and the drying time is 1.5-2.5h.

9. The method for preparing the carbon nanotube / graphene / magnetic MOF composite broadband shielded cable according to claim 1, characterized in that: The temperature of high-temperature carbonization is 550-650°C, the carbonization time is 1.5-2.5h, and the carbonization atmosphere is argon.

10. A carbon nanotube / graphene / magnetic MOF composite broadband shielded cable, characterized by: It is prepared by the preparation method described in any one of claims 1-9, and comprises, from the inside to the outside, a conductor, an internal silicone rubber protective layer, a fiber film shielding layer, a fiber braided shielding layer and an external silicone rubber protective layer, wherein the fibers in the fiber braided shielding layer are the composite fibers.

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