A method for preparing high-performance carbon nanotube fiber tow

Abstract

The present invention relates to the technical field of carbon nanotube fibers, and provides a method for preparing high-performance carbon nanotube fiber bundles. The present invention adopts chlorosulfonic acid as the solvent of the carbon nanotube liquid crystal spinning solution, adopts acetone as the primary coagulation bath, and adopts water as the secondary coagulation bath, and obtains high-performance carbon nanotube fiber bundles by combining liquid crystal spinning with directional drawing. The preparation method provided by the present invention can achieve highly oriented arrangement of carbon nanotubes and realize the continuous preparation of hundred-meter-level carbon nanotube bundle fibers. At the same time, the present invention can improve the coagulation degree of carbon nanotube fibers, obtain uniformly distributed single filaments, and avoid the occurrence of fusion and aggregation of filaments. The results of the examples show that the number of fibers of the high-performance carbon nanotube fiber bundles prepared by the present invention is adjustable from 10 (0.01K) to 100 (0.1K), has a dense microstructure, and has the characteristics of high strength, high electrical conductivity and high thermal conductivity.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon nanotube fibers, and in particular to a method for preparing a high-performance carbon nanotube fiber bundle. Background Art

[0002] Carbon nanotubes combine the excellent properties of polymer fibers, carbon fibers, and metal fibers. At the microscopic scale, a single carbon nanotube exhibits excellent mechanical strength, electrical conductivity, and thermal conductivity. Its tensile strength can reach 100 GPa, and its theoretical electrical conductivity can reach up to 10 8 S·m -1 , thermal conductivity up to 3000W·m -1 ·K -1 Carbon nanotube fibers are macroscopic continuous fiber materials constructed from nanometer-scale carbon nanotubes as assembly units, with diameters reaching the micron level. The mechanical, electrical, and thermal properties of these high-performance carbon nanotube fibers far surpass those of traditional high-performance fibers such as carbon fibers, poly(p-phenylene benzobisoxazole) fibers, and Kevlar fibers. Therefore, carbon nanotube fibers are expected to become a new generation of carbon-based high-performance fiber materials, with broad application prospects in fields such as structurally integrated functional composite materials.

[0003] Currently, the main methods for preparing high-performance carbon nanotube fibers include array spinning, floating catalyst chemical vapor deposition direct spinning, and solution spinning. Solution spinning uses a carbon nanotube dispersion as the spinning solution. Drawing on traditional solution spinning techniques, the spinning solution is injected into a coagulation bath to form carbon nanotube fibers. This method draws on the established chemical fiber wet spinning technology, making it a significant advantage in the subsequent industrialization of fibers. However, high aspect ratio carbon nanotubes are prone to entanglement during the spinning process, which not only reduces the degree of carbon nanotube orientation in the fiber but also blocks the pores, significantly reducing the continuity of the spinning process and making it difficult to produce filaments. Furthermore, during the tow preparation process, the nascent filaments do not fully solidify in the coagulation bath, which easily leads to fusion and aggregation of the filaments, making it difficult to disperse the tow into evenly distributed single filaments.

[0004] In summary, there is an urgent need to provide a method for preparing high-performance carbon nanotube fiber bundles with a high degree of orientation reduction, good continuity, and high degree of coagulation, so as to achieve large-scale preparation of high-performance carbon nanotube fiber bundles. Summary of the Invention

[0005] In light of this, the present invention provides a method for preparing high-performance carbon nanotube fiber bundles. This method can achieve highly oriented carbon nanotube fibers, enabling the continuous preparation of hundreds of meters of carbon nanotube fiber bundles. Furthermore, the fibers achieve a high degree of coagulation, resulting in uniformly dispersed monofilaments.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] A method for preparing a high-performance carbon nanotube fiber tow comprises the following steps:

[0008] mixing carbon nanotubes and chlorosulfonic acid to obtain a carbon nanotube liquid crystal spinning solution;

[0009] Extruding the carbon nanotube liquid crystal spinning solution into a primary coagulation bath for solidification to obtain a nascent fiber bundle; the coagulant used in the primary coagulation bath is acetone;

[0010] Under the action of directional drawing, the spun fiber tow enters a secondary coagulation bath for solidification to obtain the high-performance carbon nanotube fiber tow; the coagulant used in the secondary coagulation bath is water.

[0011] Preferably, the carbon nanotubes are few-walled carbon nanotubes; the aspect ratio of the carbon nanotubes is greater than 4000, the G / D ratio of the Raman spectrum is greater than 20, and the impurity content is less than 1 wt%.

[0012] Preferably, the concentration of carbon nanotubes in the carbon nanotube liquid crystal spinning solution is 1-2 wt%.

[0013] Preferably, the extrusion rate of the carbon nanotube liquid crystal spinning solution is 50 to 150 μL·min -1 .

[0014] Preferably, the residence time of the filaments in the primary coagulation bath is 5 to 20 seconds, and the temperature of the primary coagulation bath is room temperature; the residence time of the filaments in the secondary coagulation bath is 5 to 15 seconds, and the temperature of the secondary coagulation bath is room temperature;

[0015] Preferably, the draw ratio of the directional drawing is 1.5-2.

[0016] Preferably, the carbon nanotube liquid crystal spinning solution is sprayed into the primary coagulation bath through a multi-hole spinneret assembly.

[0017] Preferably, the device for preparing the high-performance carbon nanotube fiber bundle includes an extrusion device, a primary coagulation bath, an auxiliary roller, a secondary coagulation bath and a winding roller; the extrusion device includes a charging kettle and a porous spinneret assembly, and the charging kettle and the porous spinneret assembly are connected through a gooseneck tube; the outlet of the porous spinneret assembly is located in the primary coagulation bath; the primary coagulation bath and the secondary coagulation bath are arranged in sequence in the stretching direction of the bundle; the winding roller is arranged after the secondary coagulation bath; the auxiliary roller is arranged between the primary coagulation bath and the secondary coagulation bath.

[0018] Preferably, the porous spinneret assembly has 10 to 100 holes and an inner diameter of 80 to 150 μm.

[0019] Preferably, the number of fibers in the high-performance carbon nanotube fiber bundle is 10 to 100, and the diameter of a single fiber is 10 to 22 μm; the tensile strength of a single fiber in the high-performance carbon nanotube fiber bundle is 0.7 to 5.5 GPa, and the electrical conductivity is 0.8 to 15 MS·m -1 , thermal conductivity is 200~400W·m -1 ·K -1 .

[0020] The present invention provides a method for preparing a high-performance carbon nanotube fiber bundle, comprising the following steps: mixing carbon nanotubes and chlorosulfonic acid to obtain a carbon nanotube liquid crystal spinning solution; extruding the carbon nanotube liquid crystal spinning solution into a primary coagulation bath for curing to obtain a nascent fiber bundle; the coagulant used in the primary coagulation bath is acetone; under the action of directional drafting, the nascent fiber bundle enters a secondary coagulation bath for curing to obtain the high-performance carbon nanotube fiber bundle; the coagulant used in the secondary coagulation bath is water. The present invention uses chlorosulfonic acid as the solvent for the carbon nanotube liquid crystal spinning solution and acetone as the primary coagulation bath. The low diffusion rate of chlorosulfonic acid in acetone is utilized to reduce the intensity of the diffusion process, thereby achieving uniform shrinkage and curing of the carbon nanotube liquid crystal spinning solution in the primary coagulation bath, forming a continuous gel-like nascent fiber bundle; at the same time, the present invention uses water as the secondary coagulation bath. The nascent fiber bundle enters the secondary coagulation bath under tension drafting to remove residual solvent in the fiber, thereby achieving highly oriented arrangement and high-density stacking of carbon nanotubes in the fiber. In summary, the present invention utilizes liquid crystal spinning technology to achieve shear orientation of a thin stream of carbon nanotube liquid crystal spinning solution in a spinneret. Combined with directional drafting, this technology achieves highly oriented arrangement of carbon nanotubes, resulting in high-performance carbon nanotube fiber bundles and the continuous production of hundreds of meters of carbon nanotube fiber bundles. Furthermore, the present invention can improve the coagulation of carbon nanotube fibers, resulting in evenly distributed monofilaments and preventing fusion and aggregation of the strands. The results of the examples show that the high-performance carbon nanotube fiber bundles prepared by the present invention have an adjustable fiber count between 10 (0.01K) and 100 (0.1K), possess a dense microstructure, and exhibit high strength, high electrical conductivity, and high thermal conductivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Schematic diagram of the structure of the apparatus for preparing high-performance carbon nanotube fiber bundles of the present invention, wherein: 1 - charging kettle, 2 - gooseneck, 3 - multi-hole spinneret assembly, 4 - primary coagulation bath, 5 - auxiliary roller, 6 - secondary coagulation bath, 7 - winding roller;

[0022] Figure 2Schematic diagrams of the structure of the multi-hole spinneret assembly, wherein (a) is a diagram of the overall structure of the multi-hole spinneret assembly, (b) is a schematic diagram of the internal structure of the spinneret plate, (c) is a schematic diagram of the structure of the spinneret holes, and (d) is a schematic diagram of the shear flow orientation of the carbon nanotube liquid crystal spinning solution in the spinneret holes; Figure 2 Middle: 3-1—spinneret, 3-2—spinneret hole, 3-3—carbon nanotube liquid crystal spinning solution flowing through the spinneret hole for shear drawing;

[0023] Figure 3 Raman spectra of the few-walled carbon nanotubes used in the examples;

[0024] Figure 4 This is a scanning electron microscope image of the carbon nanotube fiber bundle prepared in Example 1, with a scale of 200 μm;

[0025] Figure 5 This is a scanning electron microscope image of the carbon nanotube fiber bundle prepared in Example 1, with a scale of 50 μm;

[0026] Figure 6 Scanning electron micrographs of the cross-section of the carbon nanotube fiber bundle prepared in Example 1 obtained by focused ion beam cutting, wherein the scale of (a) is 40 μm and the scale of (b) is 5 μm;

[0027] Figure 7 This is an optical photograph of the carbon nanotube fiber bundle prepared in Example 1;

[0028] Figure 8 This is a scanning electron microscope image of the carbon nanotube fiber bundle prepared in Example 2;

[0029] Figure 9 This is a scanning electron microscope image of the carbon nanotube fiber bundle prepared in Example 3;

[0030] Figure 10 This is a scanning electron microscope image of the carbon nanotube fiber bundle prepared in Comparative Example 1;

[0031] Figure 11 This is a scanning electron microscope image of the carbon nanotube fiber bundle prepared in Comparative Example 2. DETAILED DESCRIPTION

[0032] The present invention provides a method for preparing a high-performance carbon nanotube fiber tow, comprising the following steps:

[0033] mixing carbon nanotubes and chlorosulfonic acid to obtain a carbon nanotube liquid crystal spinning solution;

[0034] Extruding the carbon nanotube liquid crystal spinning solution into a primary coagulation bath for solidification to obtain a nascent fiber bundle; the coagulant used in the primary coagulation bath is acetone;

[0035] Under the action of directional drawing, the spun fiber tow enters a secondary coagulation bath for solidification to obtain the high-performance carbon nanotube fiber tow; the coagulant used in the secondary coagulation bath is water.

[0036] The invention mixes carbon nanotubes and chlorosulfonic acid to obtain carbon nanotube liquid crystal spinning solution. In the present invention, the carbon nanotubes are preferably few-walled carbon nanotubes; the few-walled carbon nanotubes are preferably one or more of single-walled carbon nanotubes, double-walled carbon nanotubes and triple-walled carbon nanotubes; the aspect ratio of the carbon nanotubes is preferably greater than 4000, more preferably 4000-5000, and the impurity content is preferably less than 1wt%; the G / D value in the Raman spectrum of the carbon nanotubes is preferably not less than 20, more preferably 20-30; the concentration of the chlorosulfonic acid is preferably 99.5wt%; the mass fraction of the carbon nanotubes in the spinning solution is preferably 1-2wt%, more preferably 1.25-1.75wt%; the present invention has no special requirements for the mixing method of the carbon nanotubes and chlorosulfonic acid, as long as the carbon nanotubes can be fully dispersed in the chlorosulfonic acid. In a specific embodiment of the present invention, the carbon nanotubes are preferably added to the chlorosulfonic acid, and then the mixture is stirred at a speed of 3000r / min for 20min in a dual-center disperser to obtain a uniform and stable carbon nanotube liquid crystal spinning solution.

[0037] After obtaining the carbon nanotube liquid crystal spinning solution, the present invention extrudes the carbon nanotube liquid crystal spinning solution into a primary coagulation bath for solidification to obtain a nascent fiber bundle; the coagulant used in the primary coagulation bath is acetone. In the present invention, the coagulant used in the primary coagulation bath is preferably acetone; the residence time of the filaments in the primary coagulation bath is preferably 5 to 20 seconds, more preferably 10 to 15 seconds, and the temperature of the primary coagulation bath is preferably room temperature; the extrusion rate of the carbon nanotube liquid crystal spinning solution is preferably 50 to 150 μL·min -1 , more preferably 100 μL·min -1 The carbon nanotube liquid crystal spinning solution is preferably extruded into a primary coagulation bath through a multi-hole spinneret assembly. The structure of the multi-hole spinneret assembly will be described in detail later. After the carbon nanotube liquid crystal spinning solution is extruded into the primary coagulation bath, chlorosulfonic acid slowly diffuses in acetone, achieving uniform shrinkage and solidification of the carbon nanotubes, forming a continuous gel-like primary fiber bundle. The primary fiber bundle preferably has 10 to 100 fibers.

[0038] After obtaining the spun fiber tow, the spun fiber tow enters a secondary coagulation bath for curing under oriented drawing to obtain the high-performance carbon nanotube fiber tow; the coagulant used in the secondary coagulation bath is water. In the present invention, the residence time of the filaments in the secondary coagulation bath is preferably 5 to 15 seconds, more preferably 10 to 15 seconds; the temperature of the secondary coagulation bath is preferably room temperature; the draft ratio of the oriented drafting is preferably 1.5 to 2.0, more preferably 2.0. In a specific embodiment of the present invention, the spun fiber tow is preferably introduced into the secondary coagulation bath via an auxiliary roller; in the secondary coagulation bath, residual chlorosulfonic acid in the spun fiber tow diffuses into the coagulant in the secondary coagulation bath, further curing the spun fiber tow, thereby improving the orientation and density of the carbon nanotubes in the fiber. In a specific embodiment of the present invention, the filaments coagulated in the secondary coagulation bath are preferably wound and collected by a take-up roller. The draft ratio can be adjusted by adjusting the tension generated by the auxiliary roller and the take-up roller. The higher the speed of the take-up roller, the higher the draft ratio.

[0039] In the present invention, the device for preparing the high-performance carbon nanotube fiber bundle preferably includes an extrusion device, a primary coagulation bath, an auxiliary roller, a secondary coagulation bath and a winding roller; the extrusion device preferably includes a charging kettle and a porous spinneret assembly, and the charging kettle and the porous spinneret assembly are preferably connected through a gooseneck tube; the outlet of the porous spinneret assembly is preferably located in the primary coagulation bath; the primary coagulation bath and the secondary coagulation bath are arranged in sequence in the stretching direction of the bundle; the winding roller is arranged after the secondary coagulation bath; the auxiliary roller is arranged between the primary coagulation bath and the secondary coagulation bath; the present invention has no special requirements for the number of the auxiliary rollers, and multiple rollers can be set to achieve smooth transmission of the filaments and cooperate with the winding roller to achieve adjustment of the stretch ratio. Figure 1 This is a schematic diagram of the structure of the device for preparing high-performance carbon nanotube fiber bundles of the present invention, wherein: 1-charging kettle, 2-gooseneck tube, 3-multi-hole spinneret assembly, 4-primary coagulation bath, 5-auxiliary roller, 6-secondary coagulation bath, 7-winding roller.

[0040] In the present invention, the porous spinneret assembly preferably includes a spinneret plate, on which a plurality of spinneret holes are provided; the spinneret holes are preferably conical holes; the number of holes in the porous spinneret assembly is preferably 10 to 100, and the pore size is preferably 80 to 150 μm, and the pore size is specifically the diameter of the small pore surface of the conical spinneret hole; in a specific embodiment of the present invention, the number of fibers in the fiber bundle can be adjusted by adjusting the number of holes in the spinneret holes. Figure 2 Schematic diagrams of the structure of the multi-hole spinneret assembly, wherein (a) is a diagram of the overall structure of the multi-hole spinneret assembly, (b) is a schematic diagram of the internal structure of the spinneret plate, (c) is a schematic diagram of the structure of the spinneret holes, and (d) is a schematic diagram of the shear flow orientation of the carbon nanotube liquid crystal spinning solution in the spinneret holes; Figure 2Middle: 3-1—spinneret, 3-2—spinneret hole, 3-3—carbon nanotube liquid crystal spinning solution flowing through the spinneret hole for shear drawing.

[0041] The following combination Figures 1 and 2 The specific preparation process of the present invention is described as follows: the carbon nanotube liquid crystal spinning solution is placed in a charging kettle 1, squeezed into a porous spinneret assembly 3 through a gooseneck tube 2, and enters a primary coagulation bath 4 under the shear action of the fluid to obtain a nascent fiber bundle; the nascent fiber bundle enters a secondary coagulation bath 6 through an auxiliary roller 5, and the solidified carbon nanotube fiber bundle is wound up by a winding roller 7 to obtain a finished carbon nanotube fiber bundle.

[0042] In the present invention, the length of the high-performance carbon nanotube fiber bundle is on the order of hundreds of meters; the number of fibers in the high-performance carbon nanotube fiber bundle is 10 to 100, and the diameter of a single fiber is 10 to 22 μm; the tensile strength of a single fiber in the high-performance carbon nanotube fiber bundle is 0.7 to 5.5 GPa, and the electrical conductivity is 0.8 to 15 MS·m -1 , thermal conductivity is 200~400W·m -1 ·K -1 .

[0043] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0044] Example 1

[0045] (1) 150 mg of few-walled carbon nanotubes were dispersed in 6 mL of 99.5 wt% chlorosulfonic acid and stirred at 3000 r / min for 20 min in a dual-center disperser to prepare a carbon nanotube liquid crystal spinning solution with a mass fraction of 1.5 wt% and uniform and stable.

[0046] (2) The carbon nanotube liquid crystal spinning solution prepared in step (1) was transferred to the charging kettle of the extruder, and a spinneret with an inner diameter of 100 μm and 50 holes was selected, and the extrusion rate was set to 100 μL·min -1 The carbon nanotube spinning solution in the charging kettle is injected into the primary coagulation bath filled with acetone through a gooseneck tube to prepare a nascent fiber tow. The nascent fiber tow is introduced into the secondary coagulation bath filled with water via an auxiliary roller for solidification. Finally, the carbon nanotube fiber tow is wound up by a winding roller. Under this condition, the maximum draw ratio of the fiber is 2.0.

[0047] Raman spectroscopy was performed on the few-walled carbon nanotubes used in this example, and the results were as follows: Figure 3 shown; according to Figure 3 It can be seen that this embodiment uses the Raman spectrum of moth-walled carbon nanotubes I G / I D The value is 28.3±2.1, indicating that the carbon nanotube raw material has a high crystallinity structural characteristic.

[0048] Figures 4 and 5 This is a scanning electron microscope image of the carbon nanotube fiber bundle prepared in this example. Figure 4 The scale bar is 200 μm. Figure 5 The scale bar is 50μm; according to Figure 4 It can be seen that the diameter of the single filament of the carbon nanotube fiber bundle prepared in this embodiment is stable at 10 to 22 μm. Figure 5 It can be seen that the carbon nanotube fibers prepared in this embodiment have uniform diameters and smooth surfaces.

[0049] Figure 6 The scanning electron microscope images of the fiber cross section obtained by cutting the carbon nanotube fiber bundle prepared in this embodiment through the focused ion beam, wherein the scale of (a) is 40 μm and the scale of (b) is 5 μm; Figure 6 It can be seen that the carbon nanotube fibers prepared in this embodiment have a relatively high density.

[0050] Figure 7 This is an optical photograph of the carbon nanotube fiber bundle prepared in this embodiment; the present invention can achieve continuous preparation of carbon nanotube fiber bundles at the hundred-meter level.

[0051] The carbon nanotube fibers prepared in this example were characterized. The results showed that the tensile strength of the carbon nanotube fibers was 5.5 GPa, and the electrical conductivity of the fibers was 11 MS·m·s using the four-probe method. -1 The thermal conductivity of the fiber was determined to be 321 W·m using the 3ω steady-state method. -1 ·K -1 ; The number of fibers in the carbon nanotube fiber bundle is 50.

[0052] Example 2

[0053] Other conditions were the same as those in Example 1, except that the maximum draft ratio of the fiber in step 2 was changed to 1.6 and the number of spinneret holes was changed to 80 holes.

[0054] The carbon nanotube fibers prepared in this example were structurally characterized. Figure 8 This is a scanning electron microscope image of the carbon nanotube fiber bundle prepared in this example. Figure 8The results show that the carbon nanotube fibers prepared in this example have uniform diameters, ranging from 11 to 15 μm. The carbon nanotube fibers prepared in this example were characterized, and the results showed that the tensile strength of the carbon nanotube fibers was 3.8 GPa, and the electrical conductivity of the fibers was 8 MS·m as measured by the four-probe method. -1 The thermal conductivity of the fiber was determined to be 260 W·m using the 3ω steady-state method. -1 ·K -1 ; The number of fibers in the carbon nanotube fiber bundle is 80.

[0055] Example 3

[0056] Other conditions were the same as those in Example 1, except that the maximum draft ratio of the fiber in step 2 was changed to 1.4 and the number of spinneret holes was changed to 100 holes.

[0057] The carbon nanotube fibers prepared in this example were structurally characterized. Figure 9 This is a scanning electron microscope image of the carbon nanotube fiber bundle prepared in this example. Figure 9 The results show that the diameter of the carbon nanotube fiber bundle prepared in this example is relatively uniform, with a fiber diameter of 12 to 20 μm. The performance of the carbon nanotube fibers prepared in this example was characterized, and the results showed that the tensile strength of the carbon nanotube fibers was 2.8 GPa, and the electrical conductivity of the fibers was 6 MS·m when measured using the four-probe method. -1 The thermal conductivity of the fiber was determined using the 3ω steady-state method to be 200 W·m -1 ·K -1 ; The number of fibers in the carbon nanotube fiber bundle is 100.

[0058] Comparative Example 1

[0059] Other conditions were the same as those in Example 1, except that the primary coagulation bath in step 2 was replaced with N,N-dimethylformamide.

[0060] The carbon nanotube fibers prepared in this example were structurally characterized. Figure 10 This is a scanning electron microscope image of the carbon nanotube fiber bundle prepared in Comparative Example 1. Figure 10 The results show that the carbon nanotube fibers prepared in Comparative Example 1 have a large diameter deviation, and there are cross-branched tube bundles distributed on the surface. The fiber diameter is 15-20 μm. The performance of the carbon nanotube fibers prepared in this comparative example was characterized. The results showed that the tensile strength of the carbon nanotube fibers was only 1.2 GPa, and the conductivity of the fibers measured by the four-probe method was 2 MS·m -1 The thermal conductivity of the fiber was determined to be 230 W·m using the 3ω steady-state method. -1 ·K -1 .

[0061] Comparative Example 2

[0062] Other conditions were the same as those in Example 1, except that the solvent of the secondary coagulation bath in step 2 was replaced with ethanol.

[0063] The carbon nanotube fibers prepared in this comparative example were structurally characterized. Figure 11 This is a scanning electron microscope image of the carbon nanotube fiber bundle prepared in Comparative Example 2. Figure 11 The results show that the carbon nanotube fibers prepared in this comparative example have a large number of unsolidified branched bundles on their surface, with a fiber diameter of 15 to 18 μm. The carbon nanotube fibers prepared in this comparative example were characterized, and the results showed that the tensile strength of the carbon nanotube fibers was only 0.8 GPa, and the electrical conductivity of the fibers measured by the four-probe method was 1 MS·m -1 The thermal conductivity of the fiber was determined to be 201 W·m using the 3ω steady-state method. -1 ·K -1 .

[0064] In summary, the present invention utilizes liquid crystal spinning technology to achieve flow shear orientation of the carbon nanotube spinning solution stream in the spinneret, and combines it with directional drawing to achieve highly oriented arrangement of the carbon nanotubes, thereby obtaining high-performance carbon nanotube fiber bundles, and realizing the continuous preparation of hundred-meter-level carbon nanotube fiber bundles. The number of fibers can be adjusted from 10 (0.01K) to 100 (0.1K), and finally obtains carbon nanotube fibers with a dense microstructure, which have the characteristics of high strength, high electrical conductivity and high thermal conductivity.

[0065] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for preparing high-performance carbon nanotube fiber tow, characterized in that: The steps are: mixing carbon nanotubes and chlorosulfonic acid to obtain a carbon nanotube liquid crystal spinning solution; Extruding the carbon nanotube liquid crystal spinning solution into a primary coagulation bath for solidification to obtain a nascent fiber bundle; the coagulant used in the primary coagulation bath is acetone; Under the action of directional drawing, the as-spun fiber tow enters a secondary coagulation bath for solidification to obtain the high-performance carbon nanotube fiber tow; The coagulant used in the secondary coagulation bath is water; The carbon nanotubes are few-walled carbon nanotubes; the aspect ratio of the carbon nanotubes is greater than 4000, the G / D ratio of the Raman spectrum is greater than 20, and the impurity content is less than 1wt%; the draw ratio of the directional drawing is 2; the number of fibers in the high-performance carbon nanotube fiber tow is 10 to 100.

2. The preparation method according to claim 1, characterized in that The concentration of carbon nanotubes in the carbon nanotube liquid crystal spinning solution is 1-2 wt%.

3. The preparation method according to claim 1, characterized in that The extrusion rate of the carbon nanotube liquid crystal spinning solution is 50 to 150 μL·min -1 .

4. The preparation method according to claim 1, characterized in that The residence time of the filaments in the primary coagulation bath is 5 to 20 seconds, and the temperature of the primary coagulation bath is room temperature; the residence time of the filaments in the secondary coagulation bath is 5 to 15 seconds, and the temperature of the secondary coagulation bath is room temperature.

5. The preparation method according to claim 1, characterized in that The carbon nanotube liquid crystal spinning solution is sprayed into a primary coagulation bath through a multi-hole spinning assembly.

6. The preparation method according to claim 1, characterized in that The device for preparing the high-performance carbon nanotube fiber bundle includes an extrusion device, a primary coagulation bath, an auxiliary roller, a secondary coagulation bath and a winding roller; the extrusion device includes a charging kettle and a porous spinneret assembly, and the charging kettle and the porous spinneret assembly are connected through a gooseneck tube; the outlet of the porous spinneret assembly is located in the primary coagulation bath; the primary coagulation bath and the secondary coagulation bath are arranged in sequence in the stretching direction of the bundle; the winding roller is arranged after the secondary coagulation bath; the auxiliary roller is arranged between the primary coagulation bath and the secondary coagulation bath.

7. The preparation method according to claim 5 or 6, characterized in that: The number of holes in the multi-hole spinneret assembly is 10 to 100, and the inner diameter is 80 to 150 μm.

8. The preparation method according to claim 1, characterized in that The diameter of a single fiber of the high-performance carbon nanotube fiber bundle is 10 to 22 μm; the tensile strength of a single fiber in the high-performance carbon nanotube fiber bundle is 0.7 to 5.5 GPa, and the electrical conductivity is 0.8 to 15 MS·m -1 , thermal conductivity is 200~400W·m -1 ·K -1 .

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