Carbon nanotube hollow fiber with multi-channel structure and preparation method thereof

Abstract

The present application relates to the technical field of multi-channel structure fiber, in particular to a carbon nanotube hollow fiber with multi-channel structure and a preparation method thereof. The present application takes vinylon filament as baseline, firstly coats carbon nanotubes on the surface of single baseline by physical coating method to obtain composite fiber; arranges the composite fiber in parallel to form new baseline, and coats carbon nanotubes again to prepare multi-core vinylon carbon nanotube composite fiber; adopts heat treatment method to pyrolyze and remove the baseline of the multi-core vinylon carbon nanotube composite fiber to obtain carbon nanotube hollow fiber with multi-channel structure. Meanwhile, by adjusting the number of composite fibers and the number of vinylon filament baseline, the number of channels and the inner diameter of the hollow fiber can be controlled. The fiber of the present application is a self-supporting hollow tubular structure composed of pure carbon nanotubes, the process is green and environmentally friendly, and can be continuously implemented. There is no damage to the structure of carbon nanotubes in the heat treatment process, and the prepared multi-channel carbon nanotube hollow fiber has excellent mechanical and electrical properties.

Description

Technical Field

[0001] This invention relates to the field of multi-channel structure fiber technology, and in particular to a carbon nanotube hollow fiber with a multi-channel structure and its preparation method. Background Technology

[0002] Carbon nanotube fibers are functional materials macroscopically assembled from carbon nanotubes oriented along their axial direction. They possess excellent properties such as high tensile strength, high electrical conductivity, and high thermal conductivity, making them valuable for applications in aerospace, new energy, smart wearables, and catalytic separation. Among these, hollow carbon nanotube fibers, due to their high porosity, high specific surface area, and low apparent density, exhibit more significant performance advantages than solid carbon nanotube fibers in applications such as energy storage electrodes, catalyst supports, and lightweight composite materials.

[0003] Currently reported methods for preparing carbon nanotube hollow fibers include electrospinning, wet spinning, and template methods. For example, patent (CN 114574982 A) uses electrospinning combined with high-temperature calcination to prepare oxide hollow fibers, followed by in-situ growth of carbon nanotubes via gas-phase catalysis to obtain zirconium oxide / cobalt / carbon nanotube composite hollow fibers. However, this process involves high calcination temperatures, which can easily cause fiber embrittlement and decreased mechanical properties. Furthermore, the uniformity of carbon nanotube growth is difficult to control, and the resulting hollow fibers are not entirely composed of pure carbon nanotubes. Literature (Desalination, 2022, 541, 116044) uses coaxial wet spinning to prepare carbon nanotube hollow fibers. This process requires the use of spinning aids, which must be removed by high-temperature calcination. The process is complex and energy-intensive, making large-scale production difficult. Patent (ZL 2024 1 0889382.1) proposes the preparation of carbon nanotube hollow fibers using vinylon filaments as templates, achieving controllable preparation of single-channel pure carbon nanotube hollow fibers. However, this method uses a water-soluble method to remove the vinylon baseline, and the resulting wastewater containing polyvinyl alcohol (PVA) will cause environmental pollution. As indicated in the literature (Chemical Fiber & Textile Technology, 2025, 54, 31), PVA has poor biodegradability and high surface activity, easily forming a foam layer in water bodies, inhibiting water reoxygenation and aquatic organism respiration, and damaging the aquatic ecosystem; at the same time, it will reduce the activity of aerobic microorganisms, weaken the self-purification capacity of water bodies, and promote the activation of heavy metals in bottom sediments, exacerbating the ecological risks to the aquatic environment. Direct discharge can easily lead to water quality deterioration and secondary pollution.

[0004] Meanwhile, existing methods for preparing hollow carbon nanotubes all produce single-channel structures, which suffer from insufficient mechanical properties. In contrast, multi-channel structures can enhance mechanical properties through the mutual support and synergistic load-bearing effect between the pore walls of each channel, becoming a key direction for solving the aforementioned problems. However, there is currently no continuous method for preparing multi-channel hollow carbon nanotubes that can precisely control the number and pore size of the channels.

[0005] In summary, developing a green, environmentally friendly, continuous preparation method for multi-channel carbon nanotube hollow fibers with adjustable channel number and pore size, and excellent mechanical and electrical properties, has significant practical application value and industrialization significance. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of existing single-channel hollow carbon nanotube fibers in terms of mechanical and electrical properties, and to reduce environmental pollution generated during the preparation process.

[0007] To address the aforementioned technical problems, this invention provides a method for preparing carbon nanotube hollow fibers with a multi-channel structure, comprising the following steps: S11: Using vinylon filament as the baseline, carbon nanotubes are coated on the surface of the baseline to obtain composite fibers; S12: Bundle multiple composite fibers together, and then coat the surface of the resulting fiber bundle with carbon nanotubes again to obtain multi-core vinylon carbon nanotube composite fibers. S13: The multi-core vinylon carbon nanotube composite fiber is heat-treated in a muffle furnace at 350-450℃ for 1-3 h to obtain the hollow carbon nanotube fiber with a multi-channel structure.

[0008] This invention uses vinylon filaments as a baseline. First, carbon nanotubes are coated onto the surface of a single baseline using a physical coating method to obtain composite fibers. Then, the resulting composite fibers are arranged in parallel to form new baselines, and carbon nanotubes are coated again to produce multi-core vinylon carbon nanotube composite fibers. Subsequently, a heat treatment method is used to pyrolyze and remove the baselines from the multi-core vinylon carbon nanotube composite fibers, ultimately obtaining hollow carbon nanotube fibers with a multi-channel structure. By controlling the number of composite fibers and the number of vinylon filaments, multi-channel hollow carbon nanotube fibers with adjustable channel number and pore size can be obtained. The heat treatment process does not damage the microstructure of carbon nanotubes and has the advantages of simple operation, continuous production, and environmental friendliness. Furthermore, the mechanical properties of the resulting multi-channel hollow carbon nanotube fibers are significantly improved compared to single-channel structures.

[0009] Preferably, in the baseline, the count of the vinylon filament is 20-100. The inner diameter of the hollow fiber channel in the multi-channel carbon nanotube can be adjusted by adjusting the count of the vinylon filament; the higher the count, the finer the vinylon filament and the smaller the inner diameter of the hollow fiber.

[0010] Preferably, the carbon nanotubes are prepared by floating catalyst chemical vapor deposition.

[0011] Furthermore, the steps for preparing carbon nanotubes by the floating catalyst chemical vapor deposition method are as follows: a mixture of catalyst precursor, growth promoter and carbon source is introduced into the reactor under the carrying of carrier gas (nitrogen) and reacted at 1200-1400℃ to obtain carbon nanotube tubular materials with single-wall or multi-wall structures.

[0012] Furthermore, the catalyst precursor is one or more of organic compounds of iron, nickel, and cobalt, as well as inorganic salts.

[0013] Furthermore, the growth promoter is a sulfur-containing organic compound.

[0014] Furthermore, the carbon source is a hydrocarbon.

[0015] Specifically, the catalyst precursor is ferrocene, the growth promoter is thiophene, and the carbon source is ethanol.

[0016] Preferably, the number of composite fibers in the fiber bundle is 2-10. The number of channels in the hollow carbon nanotubes can be adjusted by changing the number of composite fibers; the more composite fibers, the more channels the prepared hollow carbon nanotubes will have.

[0017] Preferably, in step S11 or S12, the coating method is as follows: the baseline or fiber bundle is wetted with a solvent, the wetted baseline or fiber bundle is brought into contact with carbon nanotubes, and carbon nanotubes are coated on the surface of the baseline or fiber bundle. The shrinkage effect of the solvent makes the carbon nanotubes more tightly and smoothly coated.

[0018] Furthermore, the solvent is one or more of water, ethanol, and acetone. Using solvents like water, ethanol, and acetone provides polarity suitable for the fiber substrate, allowing for rapid and uniform wetting of the substrate and fiber bundles, facilitating the adhesion of carbon nanotubes. These three solvents have moderate volatility, generating shrinkage forces during evaporation that tighten the coating layer, making it dense and smooth. Moreover, these solvents are low-cost, non-corrosive, easy to remove, and do not damage the substrate or carbon nanotube structure, thus meeting the requirements of the coating process.

[0019] Preferably, in step S11 or S12, the coating is applied 1-9 times. This range allows for adjustment of the coating thickness and density as needed, balancing coating uniformity, bonding strength, and finished product surface smoothness to meet different performance requirements.

[0020] Preferably, in step S13, the heating rate of the muffle furnace for heat treatment is 8-12℃ / min, and the heat treatment is followed by cooling to room temperature (25±5℃).

[0021] Specifically, the baseline removal method of the heat treatment is as follows: place the composite fiber in an alumina crucible, then place the crucible in the furnace chamber of a muffle furnace and seal the furnace door; heat to 400℃ at 10℃ / min and hold for 1 h; after the furnace cools naturally to room temperature, take out the sample.

[0022] The above heat treatment process can avoid damage to the carbon nanotube structure and has the technical advantages of being continuous and environmentally friendly.

[0023] The present invention also provides a carbon nanotube hollow fiber with a multi-channel structure prepared by the above-described preparation method. The multi-channel carbon nanotube hollow fiber is a macroscopic hollow fiber composed of microscopic carbon nanotubes, and the hollow fiber is a macroscopic self-supporting hollow tubular structure composed of pure carbon nanotubes.

[0024] Preferably, the hollow carbon nanotube fiber with a multi-channel structure has an inner diameter of 100-700 μm and a wall thickness of 2-40 μm.

[0025] Compared with the prior art, the above-described technical solution of the present invention has the following advantages: This invention uses vinylon filament as a baseline and coats carbon nanotubes onto the surface of the baseline to obtain composite fibers. By adjusting the number of composite fibers and the number of vinylon filaments, multi-core vinylon carbon nanotube composite fibers are prepared. Then, the baseline is removed by heat treatment to obtain multi-channel carbon nanotube hollow fibers with adjustable channel number and pore size.

[0026] The multi-channel carbon nanotube hollow fibers prepared by this invention are composed entirely of pure carbon nanotubes and possess excellent mechanical and electrical properties.

[0027] The multi-channel carbon nanotube hollow fibers prepared by this invention enhance the mechanical properties of the fibers through the mutual support and synergistic load-bearing effect between the multi-channel pore walls.

[0028] This invention achieves adjustable channel number and pore size of carbon nanotube hollow fibers by adjusting the number of composite fibers and the number of vinylon filaments.

[0029] The present invention uses a heat treatment method to remove the vinylon baseline without causing oxidation or structural damage to the carbon nanotubes, and has the technical advantages of being continuous and environmentally friendly. Attached Figure Description

[0030] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0031] Figure 1 This is a scanning electron microscope image of the 3-channel carbon nanotube hollow fiber prepared in Example 1 of this invention. Figure 1 ; Figure 2This is a scanning electron microscope image of the 3-channel carbon nanotube hollow fiber prepared in Example 1 of this invention. Figure 2 ; Figure 3 This is a scanning electron microscope image of the 5-channel carbon nanotube hollow fiber prepared in Example 2 of the present invention; Figure 4 This is a scanning electron microscope image of the 7-channel carbon nanotube hollow fiber prepared in Example 3 of the present invention; Figure 5 These are scanning electron microscope images of 5-channel carbon nanotube hollow fibers with different pore sizes prepared in Example 5 of the present invention. Figure 6 This is a comparison curve of the mechanical properties of the multi-channel carbon nanotube hollow fibers prepared in Examples 1 to 3 of the present invention and the single-channel carbon nanotube hollow fibers prepared in Comparative Example 1.

[0032] Figure 7 This is a comparison of Raman spectra of multichannel carbon nanotube hollow fibers prepared by heat treatment and hydrothermal methods in Example 1 and Comparative Example 2 of this invention. Detailed Implementation

[0033] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0034] Example 1:

[0035] This embodiment relates to a continuous preparation method for multichannel carbon nanotube hollow fibers with adjustable channel number, including the following steps: (1) Prepare the baseline: Select 60 count vinylon filament as the baseline; (2) Continuous preparation of carbon nanotube tubular materials: Carbon nanotube cylindrical structures were prepared using a floating catalyst chemical vapor deposition method. First, ferrocene and thiophene were dissolved in ethanol to form a homogeneous mixture, which was then injected into a tube furnace using a peristaltic pump. Under the influence of high-purity nitrogen, the mixture was introduced into a high-temperature reaction zone, where a catalytic cracking reaction occurred to generate carbon nanotubes. The carbon nanotubes then self-assembled in a low-temperature zone to form continuous macroscopic cylindrical structures, which were then released from the reactor into the atmosphere by a carrier gas. The mass ratio of ferrocene, thiophene, and ethanol was 98.8:0.6:0.6, and the reaction temperature was 1300℃. (3) Composite fibers were prepared by coating the baseline surface with carbon nanotube tubular material: Carbon nanotube tubes were pushed out from the baseline of the vinylon filament near the tube opening of the tubular furnace and pulled onto the baseline. The shrinkage effect of ethanol caused the tubes to form a film and adhere to the surface of the baseline, thus achieving the coating of the baseline surface with carbon nanotube tubes. The coating process was repeated 3 times to obtain composite fibers. The composite fibers were then continuously collected after being placed in a water bath and dried at 50°C for 2 hours. (4) Preparation of multi-core vinylon carbon nanotube composite fibers: Three composite fibers were arranged in parallel, and carbon nanotubes were stretched and coated onto their surface. The coating process was repeated three times to obtain multi-core vinylon carbon nanotube composite fibers. (5) Baseline removal by heat treatment yields multichannel carbon nanotube hollow fibers with adjustable channel number: The composite fibers were placed in an alumina crucible, which was then placed in the furnace chamber of a muffle furnace and the furnace door was sealed. The temperature was increased to 400℃ at 10℃ / min and held for 1 hour. The sample was then removed after the furnace cooled naturally to 25℃. The final 3-channel carbon nanotube hollow fiber is shown in the scanning electron microscope image below. Figure 1 As shown, the 3-channel hollow fiber has an inner diameter of 359±5 μm, a wall thickness of 19±5 μm, a tensile strength of 5.93 N, and a resistivity of 7.81 Ω / cm. (Reference) Figure 2 Scanning electron microscopy images at higher magnification revealed that the hollow fiber surface was densely and uniformly packed with carbon nanotubes.

[0036] Example 2:

[0037] This embodiment relates to a continuous preparation method for multichannel carbon nanotube hollow fibers with adjustable channel number, including the following steps: (1) Prepare the baseline: Select 60 count vinylon filament as the baseline; (2) Continuous preparation of carbon nanotube tubular materials: Carbon nanotube cylindrical structures were prepared using a floating catalyst chemical vapor deposition method. First, ferrocene and thiophene were dissolved in ethanol to form a homogeneous mixture, which was then injected into a tube furnace using a peristaltic pump. Under the influence of high-purity nitrogen, the mixture was introduced into a high-temperature reaction zone, where a catalytic cracking reaction occurred to generate carbon nanotubes. The carbon nanotubes then self-assembled in a low-temperature zone to form continuous macroscopic cylindrical structures, which were then released from the reactor into the atmosphere by a carrier gas. The mass ratio of ferrocene, thiophene, and ethanol was 98.8:0.6:0.6, and the reaction temperature was 1300℃. (3) Composite fibers were prepared by coating the baseline surface with carbon nanotube tubular material: Carbon nanotube tubes were pushed out from the baseline of the vinylon filament near the tube opening of the tubular furnace and pulled onto the baseline. The shrinkage effect of ethanol caused the tubes to form a film and adhere to the surface of the baseline, thus achieving the coating of the baseline surface with carbon nanotube tubes. The coating process was repeated 3 times to obtain composite fibers. The composite fibers were then continuously collected after being placed in a water bath and dried at 50°C for 2 hours. (4) Preparation of multi-core vinylon carbon nanotube composite fibers: Five composite fibers were arranged in parallel, and carbon nanotubes were stretched and coated onto their surface. The coating process was repeated three times to obtain multi-core vinylon carbon nanotube composite fibers. (5) Baseline removal by heat treatment yields multichannel carbon nanotube hollow fibers with adjustable channel number: The composite fibers were placed in an alumina crucible, which was then placed in the furnace chamber of a muffle furnace and the furnace door was sealed. The temperature was increased to 400℃ at 10℃ / min and held for 1 h. The sample was then removed after the furnace cooled naturally to 25℃. The final 5-channel carbon nanotube hollow fiber is shown in the scanning electron microscope image below. Figure 3 As shown, the 5-channel hollow fiber has an inner diameter of 443±5 μm, a wall thickness of 16.5±5 μm, a tensile strength of 8.59 N, and a resistivity of 6.51 Ω / cm.

[0038] Example 3:

[0039] This embodiment relates to a continuous preparation method for multichannel carbon nanotube hollow fibers with adjustable channel number, including the following steps: (1) Prepare the baseline: Select 60 count vinylon filament as the baseline; (2) Continuous preparation of carbon nanotube tubular materials: Carbon nanotube cylindrical structures were prepared using a floating catalyst chemical vapor deposition method. First, ferrocene and thiophene were dissolved in ethanol to form a homogeneous mixture, which was then injected into a tube furnace using a peristaltic pump. Under the influence of high-purity nitrogen, the mixture was introduced into a high-temperature reaction zone, where a catalytic cracking reaction occurred to generate carbon nanotubes. The carbon nanotubes then self-assembled in a low-temperature zone to form continuous macroscopic cylindrical structures, which were then released from the reactor into the atmosphere by a carrier gas. The mass ratio of ferrocene, thiophene, and ethanol was 98.8:0.6:0.6, and the reaction temperature was 1300℃. (3) Composite fibers were prepared by coating the baseline surface with carbon nanotube tubular material: Carbon nanotube tubes were pushed out from the baseline of the vinylon filament near the tube opening of the tubular furnace and pulled onto the baseline. The shrinkage effect of ethanol caused the tubes to form a film and adhere to the surface of the baseline, thus achieving the coating of the baseline surface with carbon nanotube tubes. The coating process was repeated 3 times to obtain composite fibers. The composite fibers were then continuously collected after being placed in a water bath and dried at 50°C for 2 hours. (4) Preparation of multi-core vinylon carbon nanotube composite fibers: Seven composite fibers were arranged in parallel, and carbon nanotubes were stretched and coated onto their surface. The coating process was repeated three times to obtain multi-core vinylon carbon nanotube composite fibers. (5) Baseline removal by heat treatment yields multichannel carbon nanotube hollow fibers with adjustable channel number: The composite fibers were placed in an alumina crucible, which was then placed in the furnace chamber of a muffle furnace and the furnace door was sealed. The temperature was increased to 400℃ at 10℃ / min and held for 1 h. The sample was then removed after the furnace cooled naturally to 25℃. The final 7-channel carbon nanotube hollow fiber is shown in the scanning electron microscope image below. Figure 4 As shown, the 7-channel hollow fiber has an inner diameter of 486±5 μm, a wall thickness of 12.7±5 μm, a tensile strength of 10.68 N, and a resistivity of 5.30 Ω / cm.

[0040] Example 4:

[0041] This embodiment relates to a continuous preparation method for multichannel carbon nanotube hollow fibers with adjustable channel number, including the following steps: (1) Prepare the baseline: Select 60 count vinylon filament as the baseline; (2) Continuous preparation of carbon nanotube tubular materials: Carbon nanotube cylindrical structures were prepared using a floating catalyst chemical vapor deposition method. First, ferrocene and thiophene were dissolved in ethanol to form a homogeneous mixture, which was then injected into a tube furnace using a peristaltic pump. Under the influence of high-purity nitrogen, the mixture was introduced into a high-temperature reaction zone, where a catalytic cracking reaction occurred to generate carbon nanotubes. The carbon nanotubes then self-assembled in a low-temperature zone to form continuous macroscopic cylindrical structures, which were then released from the reactor into the atmosphere by a carrier gas. The mass ratio of ferrocene, thiophene, and ethanol was 98.8:0.6:0.6, and the reaction temperature was 1300℃. (3) Composite fibers were prepared by coating the baseline surface with carbon nanotube tubular material: Carbon nanotube tubes were pushed out from the baseline of the vinylon filament near the tube opening of the tubular furnace and pulled onto the baseline. The shrinkage effect of ethanol caused the tubes to form a film and adhere to the surface of the baseline, thus achieving the coating of the baseline surface with carbon nanotube tubes. The coating process was repeated 3 times to obtain composite fibers. The composite fibers were then continuously collected after being placed in a water bath and dried at 50°C for 2 hours. (4) Preparation of multi-core vinylon carbon nanotube composite fibers: Ten composite fibers were arranged in parallel, and carbon nanotubes were stretched and coated onto their surface. The coating process was repeated three times to obtain multi-core vinylon carbon nanotube composite fibers. (5) Baseline removal by heat treatment yields multichannel carbon nanotube hollow fibers with adjustable channel number: The composite fibers were placed in an alumina crucible, which was then placed in the furnace chamber of a muffle furnace and the furnace door was sealed. The temperature was increased to 400℃ at 10℃ / min and held for 1 h. The sample was then removed after the furnace cooled naturally to 25℃. The final 10-channel carbon nanotube hollow fiber has an inner diameter of 532±5 μm, a wall thickness of 8.4±5 μm, a tensile strength of 13.82 N, and a resistivity of 4.08 Ω / cm.

[0042] Example 5:

[0043] This embodiment relates to a continuous preparation method for multi-channel carbon nanotube hollow fibers with adjustable internal pore size, comprising the following steps: (1) Prepare the baseline: Select 20-count, 40-count, 60-count, 80-count, and 100-count vinylon filaments as the baseline; (2) Continuous preparation of carbon nanotube tubular materials: Carbon nanotube cylindrical structures were prepared using a floating catalyst chemical vapor deposition method. First, ferrocene and thiophene were dissolved in ethanol to form a homogeneous mixture, which was then injected into a tube furnace using a peristaltic pump. Under the influence of high-purity nitrogen, the mixture was introduced into a high-temperature reaction zone, where a catalytic cracking reaction occurred to generate carbon nanotubes. The carbon nanotubes then self-assembled in a low-temperature zone to form continuous macroscopic cylindrical structures, which were then released from the reactor into the atmosphere by a carrier gas. The mass ratio of ferrocene, thiophene, and ethanol was 98.8:0.6:0.6, and the reaction temperature was 1300℃. (3) Composite fibers were prepared by coating the baseline surface with carbon nanotube tubular material: Carbon nanotube tubes were pushed out from the baseline of vinylon filaments with different counts near the tube opening of the tubular furnace and pulled onto the baseline. The shrinkage effect of ethanol caused the tubes to form a film and adhere to the baseline surface, thus achieving the coating of carbon nanotube tubes on the baseline surface. The coating process was repeated 3 times to obtain composite fibers. The composite fibers were then continuously collected after being subjected to a water bath and dried at 50°C for 2 hours. (4) Preparation of multi-core vinylon carbon nanotube composite fibers: Five composite fibers with different numbers of strands were arranged in parallel, and carbon nanotubes were stretched and coated onto their surface. The coating process was repeated three times to obtain multi-core vinylon carbon nanotube composite fibers. (5) Baseline removal by heat treatment yields multi-channel carbon nanotube hollow fibers with adjustable pore size: The composite fibers were placed in an alumina crucible, which was then placed in the furnace chamber of a muffle furnace and the furnace door was sealed. The temperature was increased to 400℃ at 10℃ / min and held for 1 h. The sample was then removed after the furnace cooled naturally to 25℃. The final 5-channel carbon nanotube hollow fibers with different pore sizes are shown in the scanning electron microscope images below. Figure 5 As shown, the inner diameter of the 5-channel hollow fiber with different channel aperture sizes is 613±5 μm, and the wall thickness is 7.8±5 μm.

[0044] Comparative Example 1: The process is basically the same as in Example 1, except that after step (3), the obtained single composite fiber is directly heat-treated to remove the vinylon baseline to obtain a single-channel carbon nanotube hollow fiber. The single-channel carbon nanotube hollow fiber has an inner diameter of 196±5 μm, a wall thickness of 24.9±5 μm, a tensile strength of 1.3 N, and a resistivity of 33.40 Ω / cm.

[0045] Comparative Example 2: The process is basically the same as in Example 1, except that after step (4), the obtained multi-core vinylon carbon nanotube composite fiber is placed in hot water at 95°C for 2 hours using a hydrothermal method to remove the vinylon baseline and obtain multi-channel carbon nanotube hollow fibers. Specifically, the hydrothermal sample contains I... D / I G The ratio is 0.267, and the resistance is 16.04 Ω / cm. This is the heat-treated sample I in Example 1. D / I G The ratio is 0.226, and the resistance is 7.81 Ω / cm.

[0046] Effect Evaluation 1: To evaluate whether the multi-channel carbon nanotube hollow fibers prepared by the above method improve the mechanical and electrical properties compared to single-channel fibers, the breaking strength and elongation at break of Examples 1 to 3 and Comparative Example 1 were tested using an electronic universal testing machine, and the resistance values ​​of Examples 1 to 4 and Comparative Example 1 were tested using a multimeter. Figure 6 As shown, the results indicate that the tensile strength of single-channel carbon nanotube hollow fibers is only 1.3 N, while that of multi-channel carbon nanotube hollow fibers is more than three times higher, demonstrating a significant improvement in mechanical properties. Furthermore, the tensile strength gradually increases with the number of channels. Simultaneously, the elongation at break of multi-channel carbon nanotube hollow fibers is maintained, with the elongation of 5-channel fibers being significantly better than that of single-channel fibers, indicating that they possess better toughness while withstanding greater tensile forces. Moreover, the resistivity per unit length of multi-channel carbon nanotube hollow fibers is significantly lower than that of single-channel fibers, and the conductivity increases by approximately 7.4 times with the increase in the number of channels. The multi-channel structure significantly reduces fiber resistance by increasing the parallel conductive pathways and effective cross-sectional area, proving that the preparation of multi-channel carbon nanotube hollow fibers is an effective way to improve the conductivity of hollow fibers.

[0047] Effect Evaluation 2: The structure of multichannel carbon nanotube fibers prepared by hydrothermal and heat treatment methods was characterized by Raman spectroscopy, and the results are as follows: Figure 7 As shown, both samples exhibit the typical D peak (~1350 cm⁻¹) of carbon materials. -1 ) and G peak (~1580 cm) -1 Characteristic signals. Among them, the I of the heat-treated sample. D / I G The ratio of 0.226 is lower than that of the hydrothermal sample. D / I G The ratio of 0.267 demonstrates that heat treatment effectively improved the graphitization degree of the fibers and reduced structural defects. Simultaneously, the resistance values ​​of samples prepared by the hydrothermal method and the heat treatment method were measured with a multimeter. The resistance of the heat-treated sample was significantly lower than that of the hydrothermal sample, indicating that heat treatment provides a structural basis for improving the conductivity, thermal stability, and mechanical properties of the fibers.

[0048] In summary, this invention uses vinylon filament as a baseline and prepares multi-core vinylon carbon nanotube composite fibers by controlling the number of coated composite fibers and the number of vinylon filaments through a carbon nanotube coating process. Subsequently, the vinylon baseline is removed by heat treatment to obtain multi-channel carbon nanotube hollow fibers with adjustable channel number and channel pore size. Compared with the single-channel structure, the prepared multi-channel carbon nanotube hollow fibers have significantly improved mechanical and electrical properties.

[0049] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for preparing carbon nanotube hollow fibers with a multi-channel structure, characterized in that, Includes the following steps: S11: Using vinylon filament as the baseline, carbon nanotubes are coated on the surface of the baseline to obtain composite fibers; S12: After bundling multiple composite fibers, carbon nanotubes are coated again on the surface of the fiber bundle to obtain multi-core vinylon carbon nanotube composite fibers. S13: The multi-core vinylon carbon nanotube composite fiber is heat-treated at 350-450℃ for 1-3 h to obtain the carbon nanotube hollow fiber with multi-channel structure.

2. The preparation method according to claim 1, characterized in that: In the baseline, the count of the vinylon filament is 20-100.

3. The preparation method according to claim 1, characterized in that: The carbon nanotubes were prepared by floating catalyst chemical vapor deposition.

4. The preparation method according to claim 1, characterized in that: The number of composite fibers in the fiber bundle is 2-10.

5. The preparation method according to claim 1, characterized in that: In step S11 or S12, the coating method is as follows: wetting the baseline or fiber bundle with a solvent, contacting the wetted baseline or fiber bundle with carbon nanotubes, and coating the surface of the baseline or fiber bundle with carbon nanotubes.

6. The preparation method according to claim 5, characterized in that: The solvent is one or more of water, ethanol, and acetone.

7. The preparation method according to claim 1, characterized in that: In step S11 or S12, the coating is applied 1-9 times.

8. The preparation method according to claim 1, characterized in that: In step S13, the heating rate of the heat treatment is 8-12℃ / min, and the product is taken out after natural cooling to room temperature.

9. A hollow carbon nanotube fiber with a multi-channel structure prepared by the preparation method according to any one of claims 1-8.

10. The carbon nanotube hollow fiber with a multi-channel structure according to claim 9, characterized in that: The hollow carbon nanotubes with multi-channel structures have an inner diameter of 100-700 μm and a wall thickness of 2-40 μm.

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