Aggregated single-walled carbon nanotube, single-walled carbon nanotube fiber material and preparation method thereof

Abstract

The present invention discloses an aggregated single-walled carbon nanotube, a single-walled carbon nanotube fiber material and a method for preparing the same. The method for preparing the aggregated single-walled carbon nanotube comprises: preparing filamentary single-walled carbon nanotubes by a floating CVD method or a plasma arc method; and, in a protective atmosphere, performing a single-walled carbon nanotube aggregation treatment on the single-walled carbon nanotubes by a rapid Joule heating system to obtain aggregated single-walled carbon nanotubes; the single-walled carbon nanotube aggregation treatment can at least make the single carbon nanotubes overlap and be arranged in a parallel orientation. The present invention uses a rapid Joule heating system for the first time to perform a rapid high-temperature heat treatment on the single-walled carbon nanotube filamentary product, and reaches an instantaneous high temperature through an extremely fast heating rate, so that the single carbon nanotubes are rapidly and orderly aggregated. The process is fast, convenient and easy to operate. At the same time, the prepared single-walled carbon nanotube fiber material has excellent tensile strength and has important commercial application value.

Description

Technical Field

[0001] The invention belongs to the technical field of nano material preparation and processing and fiber material, and specifically relates to an aggregated single-walled carbon nanotube, a single-walled carbon nanotube fiber material and a preparation method thereof. Background Art

[0002] Since the discovery of carbon nanotubes (CNTs) in 1991, their excellent mechanical and electrical properties have attracted extensive attention from researchers. Along the axis of the carbon nanotube, there are strong CC covalent bonds, which give it an ultra-high elastic modulus (up to 1TPa) and tensile strength (up to 100GPa). Especially in single-walled carbon nanotubes (SWCNTs) with a single-layer wall, under the same conditions, they have better mechanical properties. Due to its unique structure and ultra-high inherent properties, carbon nanotubes have been widely regarded as an ideal material for constructing high-strength and high-toughness fibers, and are expected to surpass carbon fibers.

[0003] In the preparation process of carbon nanotube fibers formed by spinning carbon nanotubes, the tensile strength is greatly affected by the weak inter-tube interaction between the matrix carbon nanotubes. Generally, improving the orientation between carbon nanotubes and the density during the spinning process is a process often adopted. Patent CN202011365820.2 discloses a method for preparing high-strength and high-conductivity single-walled carbon nanotube fibers by wet spinning, in which a solvent is added to configure the single-walled carbon nanotubes into a directional liquid crystal solution through shear force, and then wet spinning is performed. The obtained fiber has a tensile strength of 3-5GPa; similarly, patent CN202310562592.5 discloses a method for preparing high-orientation, high-density, and high-conductivity double-walled carbon nanotube fibers by dry-jet wet spinning, in which the gravity-induced orientation and close packing are regulated by adjusting the height of the air section. Spinning, in the preparation of these carbon nanotube fibers, the wet spinning process with the addition of additives is complicated, and the orientation and densification are not the aggregation of single carbon nanotubes at the microscopic level; Patent CN201811042095.8 discloses a continuous device for preparing highly conductive aligned carbon nanotubes, which prepares arrayed carbon nanotubes by CVD on a silicon substrate, and then prepares aligned carbon nanotube fibers by drawing and spinning. As long as this fiber is aligned on the already formed tube bundle, the arrangement of the single carbon nanotubes does not change. Therefore, it is an urgent problem to provide a method that can achieve the oriented aggregation of single carbon nanotubes without adding organic solvents such as additives. Summary of the invention

[0004] The main purpose of the present invention is to provide an aggregated single-walled carbon nanotube, a single-walled carbon nanotube fiber material and a preparation method thereof, so as to overcome the shortcomings of the prior art.

[0005] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention includes:

[0006] The embodiment of the present invention provides a method for preparing aggregated single-walled carbon nanotubes, which comprises:

[0007] The filamentary single-walled carbon nanotubes are prepared by a floating CVD method or a plasma arc method;

[0008] And, in a protective atmosphere, a rapid Joule heating system is used to perform a single-walled carbon nanotube aggregation treatment on the single-walled carbon nanotubes to obtain aggregated single-walled carbon nanotubes; the single-walled carbon nanotube aggregation treatment can at least make the single carbon nanotubes overlap and be arranged in a parallel orientation;

[0009] The parameters adopted by the rapid Joule heating system include: using alternating current as the power source, the current is 550-1000A, the power is 210-380kW, the temperature of the single-walled carbon nanotube aggregation treatment is 3000-8500°C, and the time is 5-30min.

[0010] The embodiment of the present invention also provides aggregated single-walled carbon nanotubes prepared by the aforementioned preparation method.

[0011] The embodiment of the present invention also provides the use of the aforementioned aggregated single-walled carbon nanotubes in preparing single-walled carbon nanotube fiber materials.

[0012] The present invention also provides a method for preparing a single-walled carbon nanotube fiber material, which comprises:

[0013] The above-mentioned preparation method is used to prepare aggregated single-walled carbon nanotubes;

[0014] And, the aggregated single-walled carbon nanotubes are spun to obtain single-walled carbon nanotube fiber materials.

[0015] The embodiment of the present invention also provides a single-walled carbon nanotube fiber material prepared by the aforementioned preparation method.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] (1) The present invention uses a rapid Joule heating system for the first time to rapidly heat treat single-walled carbon nanotube filament products at high temperatures, and achieves instantaneous high temperatures through extremely fast heating rates, so that single carbon nanotubes are rapidly and orderly aggregated. The process is fast, convenient, and easy to operate.

[0018] (2) The present invention always maintains a positive pressure of the inert atmosphere inside the system during the treatment process, thereby preventing trace amounts of oxygen from entering the system and effectively preventing the carbon nanotubes from being destroyed at high temperatures;

[0019] (3) The carbon nanotube filament product after treatment by the present invention can still maintain the original filamentous form, which is convenient for direct spinning into fibers without adding additives or other solvents. The obtained carbon nanotube fibers have extremely high tensile strength;

[0020] (4) After the treatment of the present invention, individual carbon nanotubes can achieve orderly aggregation at the nanoscale, and individual single-walled carbon nanotubes are closely stacked with each other, thereby improving the orientation and density at the microscopic level. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 It is a schematic diagram of the principle of orderly aggregation of carbon nanotubes of the present invention;

[0023] Figure 2 This is a scanning electron microscope photograph of the carbon nanotubes after treatment in Example 1 of the present invention;

[0024] Figure 3a-Figure 3b This is a comparison of transmission electron microscope photos of carbon nanotubes before and after treatment in Example 1 of the present invention;

[0025] Figure 4 This is a tensile strength test analysis diagram of the carbon nanotube fiber after treatment in Example 1 of the present invention;

[0026] Figure 5 This is a transmission electron microscope photo of the carbon nanotubes after treatment in Comparative Example 1 of the present invention;

[0027] Figure 6 This is a transmission electron microscope photo of the carbon nanotubes after treatment in Comparative Example 2 of the present invention;

[0028] Figure 7 This is a transmission electron microscope photo of the carbon nanotubes after treatment in Comparative Example 3 of the present invention;

[0029] Figure 8 This is a transmission electron microscope photo of the carbon nanotubes after treatment in Comparative Example 4 of the present invention;

[0030] Fig. 9 is a transmission electron microscope photograph of the carbon nanotubes after treatment in Example 2 of the present invention;

[0031] Fig.10 is a transmission electron microscope photograph of the carbon nanotubes after treatment in Example 3 of the present invention;

[0032] Fig.11 This is a physical photo of the carbon nanotube fibers prepared in Examples 1-3 of the present invention. DETAILED DESCRIPTION

[0033] In view of the defects of the prior art, the inventors of this case have proposed the technical solution of the present invention after long-term research and extensive practice. The technical solution mainly uses single-walled carbon nanotube filament products prepared by floating CVD method or plasma arc method as raw materials, and adopts a rapid Joule heating system to process the raw materials, so that individual carbon nanotubes are arranged in parallel and tightly aggregated and stacked with each other, and finally directly spun into high-strength single-walled carbon nanotube fiber materials.

[0034] The technical solution of the present invention will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] Specifically, as one aspect of the technical solution of the present invention, a method for preparing aggregated single-walled carbon nanotubes involves:

[0036] The filamentary single-walled carbon nanotubes are prepared by a floating CVD method or a plasma arc method;

[0037] And, in a protective atmosphere, a rapid Joule heating system is used to perform a single-walled carbon nanotube aggregation treatment on the single-walled carbon nanotubes to obtain aggregated single-walled carbon nanotubes; the single-walled carbon nanotube aggregation treatment can at least make the single carbon nanotubes overlap and be arranged in a parallel orientation;

[0038] The parameters adopted by the rapid Joule heating system include: using alternating current as the power source, the current is 550-1000A, the power is 210-380kW, the temperature of the single-walled carbon nanotube aggregation treatment is 3000-8500°C, and the time is 5-30min.

[0039] In some preferred embodiments, the preparation method specifically comprises: placing a filamentary single-walled carbon nanotube in a graphite crucible and placing it in a rapid Joule heating system and evacuating the system to a vacuum degree of 10 -6 ~10 -8 Pa, then fill in a protective atmosphere and maintain the positive pressure inside the system at 0.5-50 kPa, then use a heating rate of 350-600 ° C / s to heat the graphite crucible to 3000-8500 ° C for single-walled carbon nanotube aggregation treatment to obtain filamentous aggregated single-walled carbon nanotubes.

[0040] Furthermore, the length of the filamentous single-walled carbon nanotube is 10 to 25 cm.

[0041] Furthermore, the mass of the filamentous single-walled carbon nanotube is 0.05-1.00 g.

[0042] Furthermore, the graphite filament crucible has a length of 12 to 27 cm, a width of 0.5 to 3.0 cm, and pole ears for connection are provided at both ends.

[0043] Furthermore, the volume of the rapid Joule heating system is 0.5 to 3.0 m3, and the graphite filament crucible is placed in the central area of ​​the system and the distance from the bottom is 15 to 80 cm.

[0044] Furthermore, the positive pressure inside the system is controlled to be 0.5-50 kPa by adjusting the flow rates of inlet and outlet gases, wherein the inlet flow rate is 100-700 sccm and the outlet flow rate is 90-600 sccm.

[0045] Another aspect of the embodiments of the present invention further provides aggregated single-walled carbon nanotubes prepared by the aforementioned preparation method.

[0046] Furthermore, the aggregated single-walled carbon nanotubes include more than 50 mutually overlapping single-walled carbon nanotubes within a diameter range of 10 nm.

[0047] Another aspect of the embodiments of the present invention further provides use of the aforementioned aggregated single-walled carbon nanotubes in preparing single-walled carbon nanotube fiber materials.

[0048] Another aspect of the embodiments of the present invention further provides a method for preparing a single-walled carbon nanotube fiber material, which comprises:

[0049] The above-mentioned preparation method is used to prepare aggregated single-walled carbon nanotubes;

[0050] And, the aggregated single-walled carbon nanotubes are spun to obtain single-walled carbon nanotube fiber materials.

[0051] In some preferred embodiments, the method for preparing the single-walled carbon nanotube fiber material comprises the following steps:

[0052] S1. Put an appropriate amount of single-walled carbon nanotube raw materials of appropriate specifications into the middle of the graphite wire crucible;

[0053] S2. Place the graphite crucible into the heating system, connect the electrodes at both ends, remove the air in the system, and fill it with argon atmosphere;

[0054] S3, under a certain power, start the rapid Joule heating system to make the graphite crucible part quickly reach the set high temperature, adjust the inlet and outlet flow rates to control a certain positive pressure inside the system, and perform single-walled carbon nanotube aggregation treatment;

[0055] S4. After completion, the product (i.e., filamentous aggregated single-walled carbon nanotubes) is collected and spun to obtain a single-walled carbon nanotube fiber material.

[0056] Furthermore, the appropriate amount of single-walled carbon nanotube raw material of appropriate specifications in step S1 refers to a filamentary raw material with a length of 10 to 25 cm and a weight of 0.05 to 1.00 g.

[0057] Furthermore, the graphite filament crucible has a length of 12 to 27 cm, a width of 0.5 to 3.0 cm, and pole ears for connection are provided at both ends.

[0058] Furthermore, the volume of the heating system in step S2 is 0.5 to 3.0 m 3 The graphite crucible is placed in the center of the system, 15 to 80 cm from the bottom.

[0059] Furthermore, the air in the system is removed by vacuuming with a molecular pump to a vacuum degree of 10 -6 ~10 -8 Pa.

[0060] Furthermore, in step S3, the rapid Joule heating system uses alternating current as a power source, with a current of 550-1000A, a power of 210-380kW, and a heating rate of 350-600°C / s, which can enable the graphite filament crucible to quickly reach a temperature of 3000-8500°C.

[0061] Furthermore, the regulating of the inlet and outlet flow rates means that the inlet flow rate is 100 to 700 sccm, the outlet flow rate is 90 to 600 sccm, and the positive pressure inside the control system is 0.5 to 50 kPa.

[0062] Furthermore, the aggregation treatment time is 5 to 30 minutes.

[0063] Furthermore, the spinning treatment in step S3 refers to directly spinning the obtained aggregated single-walled carbon nanotube filamentous product to form a fiber product without adding other additives.

[0064] Furthermore, the method can orderly aggregate more than 50 single-walled carbon nanotubes within a range of 10 nm.

[0065] Furthermore, the method can prepare single-walled carbon nanotube fiber materials with a diameter of 0.01 to 1.50 mm. When the diameter is 0.1 mm, the maximum tensile strength can reach 2.6 GPa, which is a high-strength material with practical value.

[0066] Another aspect of the embodiments of the present invention further provides a single-walled carbon nanotube fiber material obtained by the aforementioned preparation method.

[0067] Furthermore, the diameter of the single-walled carbon nanotube fiber material is 0.01-1.50 mm.

[0068] Furthermore, the tensile strength of the single-walled carbon nanotube fiber material is 1.0 to 2.6 GPa.

[0069] In order to achieve the orientation and compactness of a single carbon nanotube and improve the strength of the carbon nanotube fiber in essence and microscopically, the present invention uses a fast Joule heating system for the first time to treat the single-walled carbon nanotube filament product prepared by the floating process or the plasma arc method, which can quickly achieve the high orientation aggregation of a single carbon nanotube, and the single-walled carbon nanotube fiber prepared by direct spinning has extremely high tensile strength. This method does not require the addition of organic solvents such as additives, and can achieve the orientation aggregation of a single carbon nanotube.

[0070] The present invention processes conventional single-walled carbon nanotubes through a rapid Joule heating system. Due to the tube bundle assembly mechanism, it is possible to control the formation of a more tightly aggregated single-walled carbon nanotube bundle. Further, the carbon nanotube is spun into a carbon nanotube fiber. After tensile strength testing, the tensile strength can reach up to 2.6GPa when the carbon nanotube fiber diameter is 0.1mm, which is much higher than other similar products. The present invention realizes the regulation and preparation of aggregated single-walled carbon nanotubes. This ordered aggregated carbon nanotube can form a more compact bundle of superposition, and more than 50 single-walled carbon nanotubes can be aggregated within a range of 10nm. At the same time, the carbon nanotubes are adhered and overlapped in parallel, which greatly enhances the tensile strength. It is an ideal material as a high-strength fiber and has important commercial application value.

[0071] The technical solution of the present invention is further described in detail below in conjunction with several preferred embodiments and drawings. This embodiment is implemented on the premise of the technical solution of the invention, and a detailed implementation method and specific operation process are given, but the protection scope of the present invention is not limited to the following embodiments.

[0072] Unless otherwise specified, the experimental materials used in the following examples can be purchased from conventional biochemical reagent companies.

[0073] Example 1

[0074] Weigh 0.10 g of arc-prepared single-walled carbon nanotube filaments with a length of 20 cm and place them in the middle of a graphite crucible with a length of 22 cm and a width of 1.0 cm; place the graphite crucible in a 1.3 m 3 The center of the heating system is 30 cm from the bottom, and the electrodes at both ends are connected; close the gas valve, open the molecular pump to exhaust the air in the system, and pump until the pressure gauge shows 10 -7 Pa, filled with high-purity argon atmosphere; set the current to 700A, and start the rapid Joule heating system at a power of 266kW, with a heating rate of 400℃ / s, so that the graphite filament crucible part reaches a high temperature of 8000℃ in 15s, adjust the inlet flow rate in the system to 400sccm, the outlet flow rate to 350sccm, and the positive pressure inside the system to 20kPa, and carry out single-walled carbon nanotube aggregation treatment; after treating for 20min, stop heating, collect the products after cooling, and directly spin the collected filamentous products to obtain single-walled carbon nanotube fiber materials with a diameter of 0.1mm, and take samples for testing and characterization.

[0075] Figure 1 The schematic diagram of the principle of orderly aggregation of single carbon nanotubes in the process of rapid high temperature treatment of the present invention. Under normal circumstances, due to the strong van der Waals force, single carbon nanotubes will be close to each other, so that multiple single-walled carbon nanotubes adhere to each other and form a bundle morphology with tube walls close to each other. Through the external energy interference applied in the present invention, a bundle aggregation mechanism is formed, and single single-walled carbon nanotubes are stacked in an orderly manner to form an orderly aggregated single-walled carbon nanotube bundle.

[0076] Scanning electron microscope photos of carbon nanotubes after treatment Figure 2 This embodiment uses single-walled carbon nanotube raw materials prepared by plasma arc method. From the scanning electron microscope photos, it can be seen that the carbon nanotube bundles are more obvious after rapid high-temperature treatment. The length of the bundle composed of multiple carbon nanotubes can reach tens or even hundreds of microns, and the bundles are superimposed on each other to form a whole. Figure 3a-Figure 3b The state of the carbon nanotube bundle before and after the treatment was compared by transmission electron microscopy. Before the treatment, the carbon nanotubes and the carbon nanotubes were closely adjacent to each other to form a bundle, and the diameter of the bundle was usually the sum of the diameters of multiple carbon nanotubes, and no aggregation occurred. After the treatment by the method of this embodiment, the single-walled carbon nanotubes were stacked on each other in an orderly manner to form an orderly aggregated single-walled carbon nanotube bundle. Under the same scale, more carbon nanotubes were aggregated, greatly increasing the density. After careful identification, it can be determined that more than 50 single-walled carbon nanotubes are orderly aggregated within the range of 10nm. Figure 4This is an analysis chart of the tensile strength test of the carbon nanotube fiber after treatment in this embodiment. The single-walled carbon nanotube fiber sample is prepared into a spline of standard size and a tensile test of the stress-strain curve is performed. It can be seen that when the strain is 85%, the maximum breaking strength of 2.6 GPa is reached, which has very high tensile deformation and tensile strength.

[0077] Comparative Example 1

[0078] Weigh 0.10 g of arc-prepared single-walled carbon nanotube filaments with a length of 20 cm and place them in the middle of a graphite crucible with a length of 22 cm and a width of 1.0 cm; place the graphite crucible in a 1.3 m 3 The center of the heating system is 30 cm from the bottom, and the electrodes at both ends are connected; close the gas valve, open the molecular pump to exhaust the air in the system, and pump until the pressure gauge shows 10 -7 Pa, filled with high-purity argon atmosphere; set the current to 700A, and start the rapid Joule heating system at a power of 266kW, with a heating rate of 400℃ / s, so that the graphite filament crucible part reaches a high temperature of 2000℃ in 15s, adjust the system's inlet flow rate to 400sccm, the outlet flow rate to 350sccm, and the positive pressure inside the system to 20kPa, and carry out single-walled carbon nanotube aggregation treatment; after 20min of treatment, stop heating, cool and collect the products, directly spin the collected filamentous products to obtain single-walled carbon nanotube fiber materials with a diameter of 0.1mm, and take samples for testing and characterization.

[0079] Transmission electron microscope photos of carbon nanotubes after treatment Figure 5 As shown, only a few single-walled carbon nanotubes appear, and the carbon tubes cross each other without forming overlapping aggregation.

[0080] Comparative Example 2

[0081] Weigh 0.10 g of arc-prepared single-walled carbon nanotube filaments with a length of 20 cm and place them in the middle of a graphite crucible with a length of 22 cm and a width of 1.0 cm; place the graphite crucible in a 1.3 m 3 The center of the heating system is 30 cm from the bottom, and the electrodes at both ends are connected; close the gas valve, open the molecular pump to exhaust the air in the system, and pump until the pressure gauge shows 10 -7Pa, filled with high-purity argon atmosphere; set the current to 700A, and start the rapid Joule heating system at a power of 266kW, with a heating rate of 400℃ / s, so that the graphite filament crucible part reaches a high temperature of 9000℃ in 15s, adjust the inlet flow rate in the system to 400sccm, the outlet flow rate to 350sccm, and the positive pressure inside the system to 20kPa, and carry out single-walled carbon nanotube aggregation treatment; after 20min of treatment, stop heating, collect the products after cooling, and directly spin the collected filamentous products to obtain single-walled carbon nanotube fiber materials with a diameter of 0.1mm, and take samples for testing and characterization.

[0082] Transmission electron microscope photos of carbon nanotubes after treatment Figure 6 As shown, only a few single-walled carbon nanotubes appear, and the carbon nanotubes are in contact with each other without forming overlapping aggregation.

[0083] Comparative Example 3

[0084] Weigh 0.10 g of arc-prepared single-walled carbon nanotube filaments with a length of 20 cm and place them in the middle of a graphite crucible with a length of 22 cm and a width of 1.0 cm; place the graphite crucible in a 1.3 m 3 The center of the heating system is 30 cm from the bottom, and the electrodes at both ends are connected; close the gas valve, open the molecular pump to exhaust the air in the system, and pump until the pressure gauge shows 10 -7 pa, filled with high-purity argon atmosphere; set the current to 700A, and start the rapid Joule heating system at a power of 266kW. The heating rate reaches 400℃ / s, so that the graphite filament crucible part reaches a high temperature of 8000℃ in 15s, and the inlet flow rate in the system is adjusted to 400sccm, the outlet flow rate is 350sccm, and the positive pressure inside the system is controlled to 20kPa, and single-walled carbon nanotube aggregation treatment is carried out; after 1min of treatment, the heating is stopped, and the products are collected after cooling, and the collected filamentous products are directly spun to obtain single-walled carbon nanotube fiber materials with a diameter of 0.1mm, which are sampled for testing and characterization.

[0085] Transmission electron microscope photos of carbon nanotubes after treatment Figure 7 As shown, only a few single-walled carbon nanotubes appear, and the carbon nanotubes are in contact with each other without forming overlapping aggregation.

[0086] Comparative Example 4

[0087] Weigh 0.10 g of arc-prepared single-walled carbon nanotube filaments with a length of 20 cm and place them in the middle of a graphite crucible with a length of 22 cm and a width of 1.0 cm; place the graphite crucible in a 1.3 m 3The center of the heating system is 30 cm from the bottom, and the electrodes at both ends are connected; close the gas valve, open the molecular pump to exhaust the air in the system, and pump until the pressure gauge shows 10 -7 pa, filled with high-purity argon atmosphere; set the current to 700A, and start the rapid Joule heating system at a power of 266kW. The heating rate reaches 50℃ / s, so that the graphite filament crucible part reaches a high temperature of 8000℃ in 160s, and the inlet flow rate in the system is adjusted to 400sccm, the outlet flow rate is 350sccm, and the positive pressure inside the system is controlled to 20kPa, and single-walled carbon nanotube aggregation treatment is carried out; after 20min of treatment, the heating is stopped, and the products are collected after cooling, and the collected filamentous products are directly spun to obtain single-walled carbon nanotube fiber materials with a diameter of 0.1mm, which are sampled for testing and characterization.

[0088] Transmission electron microscope photos of carbon nanotubes after treatment Figure 8 As shown, only a few single-walled carbon nanotubes appear, and the carbon nanotubes are in contact with each other without forming overlapping aggregation.

[0089] Example 2

[0090] Weigh 0.30 g of arc-prepared single-walled carbon nanotube filaments with a length of 20 cm and place them in the middle of a graphite crucible with a length of 22 cm and a width of 1.0 cm; place the graphite crucible in a 1.3 m 3 The center of the heating system is 30 cm from the bottom, and the electrodes at both ends are connected; close the gas valve, open the molecular pump to exhaust the air in the system, and pump until the pressure gauge shows 10 -7 pa, filled with high-purity argon atmosphere; set the current to 900A, and start the rapid Joule heating system at a power of 342kW. The heating rate reaches 500℃ / s, so that the graphite filament crucible part reaches a high temperature of 7000℃ in 14s, and the inlet flow rate in the system is adjusted to 400sccm, the outlet flow rate is 350sccm, and the positive pressure inside the system is controlled to 20kPa, and single-walled carbon nanotube aggregation treatment is carried out; after 20min of treatment, the heating is stopped, and the products are collected after cooling, and the collected filamentous products are directly spun to obtain single-walled carbon nanotube fiber materials with a diameter of 0.5mm, which are sampled for testing and characterization.

[0091] Transmission electron microscope photos of carbon nanotubes after treatment Fig. 9 As shown. After high temperature treatment, single carbon nanotubes are tightly aggregated. Observed at a scale of 10nm, dozens of carbon nanotubes are stacked in an orderly manner, forming a clustering effect. After careful identification, it can be determined that more than 50 single-walled carbon nanotubes are orderly aggregated within the range of 10nm.

[0092] Example 3

[0093] Weigh 0.06 g of arc-prepared single-walled carbon nanotube filament raw material with a length of 20 cm and put it into the middle of a graphite crucible with a length of 22 cm and a width of 1.0 cm; put the graphite crucible into a 1.3 m 3 The center of the heating system is 30 cm from the bottom, and the electrodes at both ends are connected; close the gas valve, open the molecular pump to exhaust the air in the system, and pump until the pressure gauge shows 10 -7 pa, filled with high-purity argon atmosphere; set the current to 600A, and start the rapid Joule heating system at a power of 228kW. The heating rate reaches 380℃ / s, so that the graphite filament crucible part reaches a high temperature of 4000℃ in 10.5s, and the inlet flow rate in the system is adjusted to 400sccm, the outlet flow rate is 350sccm, and the positive pressure inside the system is controlled to 20kPa, and single-walled carbon nanotube aggregation treatment is carried out; after 20min of treatment, the heating is stopped, and the products are collected after cooling, and the collected filamentous products are directly spun to obtain single-walled carbon nanotube fiber materials with a diameter of 0.05mm, which are sampled for testing and characterization.

[0094] Transmission electron microscope photos of carbon nanotubes after treatment Fig.10 The carbon nanotubes in this example are also clearly aggregated, and multiple single-walled carbon nanotubes are orderly aggregated with each other under the 10nm scale. After careful identification, it can be determined that more than 50 single-walled carbon nanotubes are orderly aggregated within the range of 10nm.

[0095] Fig.11 The actual photos are single-walled carbon nanotube fibers obtained after spinning in Examples 1, 2 and 3. When the weight of the raw materials is different, the fibers with the same length spun have different diameters. At the same time, due to differences in the treatment process, the aggregation state is different, and the final tensile strength is also different.

[0096] Table 1 Comparison of performance parameters of single-walled carbon nanotube fiber samples with different diameters obtained in Examples 1-3 and Comparative Examples 1-4

[0097]

[0098] From the parameter comparison results in Table 1 above, it can be seen that Example 1, Example 2 and Example 3 respectively use carbon nanotube raw materials of different masses to prepare fiber materials of different diameters. At the same length, when the mass increases, the diameter of the fiber increases. At the same time, the three embodiments respectively use different high temperatures for aggregation treatment. As the temperature increases, the greater the degree of aggregation of a single single-walled carbon nanotube, the higher the density, and the tensile strength also increases. In Comparative Examples 1 and 2, when the temperature is too low (2000°C) or too high (9000°C), the aggregation of single-walled carbon nanotubes cannot be formed. In Comparative Examples 3 and 4, when the processing time is only 1 min or the heating rate is very slow, only 50°C / s, no aggregation phenomenon can be formed. At the same time, the tensile strength of the fiber materials prepared in these comparative examples is significantly reduced.

[0099] Example 4

[0100] Weigh 0.5 g of arc-prepared single-walled carbon nanotube filaments with a length of 20 cm and place them in the middle of a graphite crucible with a length of 22 cm and a width of 1.0 cm; place the graphite crucible in a 2.0 m 3 The center of the heating system is 40 cm from the bottom, and the electrodes at both ends are connected; close the gas valve, open the molecular pump to exhaust the air in the system, and pump until the pressure gauge shows 10 -7 Pa, filled with high-purity argon atmosphere; set the current to 900A, start the rapid Joule heating system at a power of 342kW, and achieve a heating rate of 550℃ / s, so that the graphite filament crucible part reaches a high temperature of 8300℃ in 15s, adjust the system's inlet flow rate to 600sccm, the outlet flow rate to 550sccm, and the positive pressure inside the system to 5kPa, and perform single-walled carbon nanotube aggregation treatment; after 25min of treatment, stop heating, cool and collect the product, and directly spin the collected filamentous product to obtain a single-walled carbon nanotube fiber material with a diameter of 0.7mm.

[0101] Example 5

[0102] Weigh 0.5 g of single-walled carbon nanotube filaments prepared by the arc method with a length of 15 cm and place them in the middle of a graphite crucible with a length of 17 cm and a width of 1.5 cm; place the graphite crucible in a 1.0 m 3 The center of the heating system is 20 cm from the bottom, and the electrodes at both ends are connected; close the gas valve, open the molecular pump to exhaust the air in the system, and pump until the pressure gauge shows 10 -7Pa, filled with high-purity argon atmosphere; set the current to 900A, start the rapid Joule heating system at a power of 342kW, and achieve a heating rate of 550℃ / s, so that the graphite filament crucible part reaches a high temperature of 8300℃ in 15s, adjust the system's inlet flow rate to 600sccm, the outlet flow rate to 550sccm, and the positive pressure inside the system to 5kPa, and perform single-walled carbon nanotube aggregation treatment; after treating for 20min, stop heating, cool and collect the product, and directly spin the collected filamentous product to obtain a single-walled carbon nanotube fiber material with a diameter of 1.0mm.

[0103] Example 6

[0104] Weigh 0.8 g of arc-prepared single-walled carbon nanotube filament raw material with a length of 23 cm and put it into the middle of a graphite crucible with a length of 25 cm and a width of 1.5 cm; put the graphite crucible into a 2.5 m 3 The center of the heating system is 50 cm from the bottom, and the electrodes at both ends are connected; close the gas valve, open the molecular pump to exhaust the air in the system, and pump until the pressure gauge shows 5×10 -7 Pa, filled with high-purity argon atmosphere; set the current to 800A, start the rapid Joule heating system at a power of 304kW, and achieve a heating rate of 500℃ / s, so that the graphite filament crucible part reaches a high temperature of 7500℃ in 15s, adjust the system's inlet flow rate to 600sccm, the outlet flow rate to 550sccm, and the positive pressure inside the system to 5kPa, and perform single-walled carbon nanotube aggregation treatment; after 20min of treatment, stop heating, cool and collect the product, and directly spin the collected filamentous product to obtain a single-walled carbon nanotube fiber material with a diameter of 1.1mm.

[0105] Example 7

[0106] Weigh 0.06 g of single-walled carbon nanotube filaments prepared by the arc method, 11 cm in length, and put them into the middle of a graphite crucible with a length of 13 cm and a width of 0.7 cm; put the graphite crucible into a 0.8 m 3 The center of the heating system is 20 cm from the bottom, and the electrodes at both ends are connected; close the gas valve, open the molecular pump to exhaust the air in the system, and pump until the pressure gauge shows 5×10 -7Pa, filled with high-purity argon atmosphere; set the current to 650A, and start the rapid Joule heating system at a power of 247kW, with a heating rate of 400℃ / s, so that the graphite filament crucible part reaches a high temperature of 3500℃ in 8.8s, adjust the system's inlet flow rate to 600sccm, the outlet flow rate to 550sccm, and the positive pressure inside the system to 5kPa, and perform single-walled carbon nanotube aggregation treatment; after treating for 20min, stop heating, cool and collect the product, and directly spin the collected filamentous product to obtain a single-walled carbon nanotube fiber material with a diameter of 0.06mm.

[0107] Example 8

[0108] Weigh 0.08 g of single-walled carbon nanotube filaments prepared by the arc method with a length of 11 cm and put them into the middle of a graphite crucible with a length of 13 cm and a width of 0.7 cm; put the graphite crucible into a 0.8 m 3 The center of the heating system is 20 cm from the bottom, and the electrodes at both ends are connected; close the gas valve, open the molecular pump to exhaust the air in the system, and pump until the pressure gauge shows 5×10 -7 Pa, filled with high-purity argon atmosphere; set the current to 950A, and start the rapid Joule heating system at a power of 361kW, with a heating rate of 580℃ / s, so that the graphite filament crucible part reaches a high temperature of 8300℃ in 14.3s, adjust the inlet flow rate in the system to 600sccm, the outlet flow rate to 550sccm, and the positive pressure inside the system to 5kPa, and carry out single-walled carbon nanotube aggregation treatment; after treating for 15min, stop heating, cool and collect the product, and directly spin the collected filamentous product to obtain a single-walled carbon nanotube fiber material with a diameter of 0.07mm.

[0109] Example 9

[0110] Weigh 0.10g of 20cm long single-walled carbon nanotube filament raw material prepared by floating CVD method and put it into the middle of a 22cm long and 1.0cm wide graphite crucible; put the graphite crucible into the center of the heating system with a volume of 1.3m3, 30cm from the bottom, and connect the electrodes at both ends; close the gas valve, open the molecular pump to remove the air in the system, and pump until the pressure gauge shows 10 -7pa, filled with high-purity argon atmosphere; set the current to 800A, and start the rapid Joule heating system at a power of 304kW, with a heating rate of 400℃ / s, so that the graphite filament crucible part reaches a high temperature of 8000℃ in 15s, adjust the system's inlet flow rate to 400sccm, the outlet flow rate to 350sccm, and the positive pressure inside the system to 20kPa, and carry out single-walled carbon nanotube aggregation treatment; after treating for 20min, stop heating, cool and collect the products, and directly spin the collected filamentous products to obtain single-walled carbon nanotube fiber materials with a diameter of 0.1mm.

[0111] Example 10

[0112] Weigh 0.30g of 20cm long single-walled carbon nanotube filament raw material prepared by floating CVD method and put it into the middle of a 22cm long and 1.0cm wide graphite crucible; put the graphite crucible into the center of the heating system with a volume of 1.3m3, 30cm from the bottom, and connect the electrodes at both ends; close the gas valve, open the molecular pump to remove the air in the system, and pump until the pressure gauge shows 10 -7 Pa, filled with high-purity argon atmosphere; set the current to 900A, and start the rapid Joule heating system at a power of 342kW, with a heating rate of 500℃ / s, so that the graphite filament crucible part reaches a high temperature of 7000℃ in 14s, adjust the inlet flow rate in the system to 400sccm, the outlet flow rate to 350sccm, and the positive pressure inside the system to 20kPa, and carry out single-walled carbon nanotube aggregation treatment; after 20min of treatment, stop heating, collect the products after cooling, and directly spin the collected filamentous products to obtain single-walled carbon nanotube fiber materials with a diameter of 0.5mm, and take samples for testing and characterization.

[0113] In addition, the inventors of this case also referred to the aforementioned embodiments and conducted experiments with other raw materials, process operations, and process conditions described in this specification, and obtained relatively ideal results.

[0114] It should be understood that the technical solution of the present invention is not limited to the above-mentioned specific implementation cases. Any technical deformation made according to the technical solution of the present invention without departing from the scope of protection of the purpose of the present invention and the claims shall fall within the protection scope of the present invention.

Claims

1. A method for preparing aggregated single-walled carbon nanotubes, characterized in that: include: The filamentary single-walled carbon nanotubes are prepared by a floating CVD method or a plasma arc method; And, in a protective atmosphere, using a rapid Joule heating system to perform single-walled carbon nanotube aggregation on the single-walled carbon nanotubes to obtain aggregated single-walled carbon nanotubes; The single-walled carbon nanotube aggregation process can at least make the single carbon nanotubes overlap and be arranged in parallel orientation; The parameters adopted by the rapid Joule heating system include: using alternating current as the power source, the current is 550-1000A, the power is 210-380kW, the temperature of the single-walled carbon nanotube aggregation treatment is 3000-8500°C, and the time is 5-30min.

2. The preparation method according to claim 1, characterized in that: Specifically include: The filamentary single-walled carbon nanotubes were placed in a graphite crucible and placed in a rapid Joule heating system to evacuate the vacuum to 10 -6 ~10 -8 Pa, then fill in a protective atmosphere and maintain the positive pressure inside the system at 0.5-50 kPa, then use a heating rate of 350-600 ° C / s to heat the graphite crucible to 3000-8500 ° C for single-walled carbon nanotube aggregation treatment to obtain filamentous aggregated single-walled carbon nanotubes.

3. The preparation method according to claim 2, characterized in that: The length of the filamentary single-walled carbon nanotube is 10 to 25 cm; and / or the mass of the filamentary single-walled carbon nanotube is 0.05 to 1.00 g; And / or, the graphite filament crucible has a length of 12 to 27 cm, a width of 0.5 to 3.0 cm, and pole ears for connection are provided at both ends.

4. The preparation method according to claim 2, characterized in that: The volume of the rapid Joule heating system is 0.5 to 3.0 m 3 , and the graphite filament crucible is placed in the central area of ​​the system and the distance from the bottom is 15 to 80 cm; And / or, the positive pressure inside the system is controlled to be 0.5-50 kPa by adjusting the flow rates of inlet and outlet gases, wherein the inlet flow rate is 100-700 sccm and the outlet flow rate is 90-600 sccm.

5. Aggregated single-walled carbon nanotubes prepared by the preparation method according to any one of claims 1 to 4.

6. The aggregated single-walled carbon nanotube according to claim 5, characterized in that: The aggregated single-walled carbon nanotubes include more than 50 mutually overlapping single-walled carbon nanotubes within a diameter range of 10 nm.

7. Use of the aggregated single-walled carbon nanotubes according to claim 5 or 6 in preparing single-walled carbon nanotube fiber materials.

8. A method for preparing a single-walled carbon nanotube fiber material, characterized in that: include: The method according to any one of claims 1 to 4 is used to prepare aggregated single-walled carbon nanotubes; And, the aggregated single-walled carbon nanotubes are spun to obtain single-walled carbon nanotube fiber materials.

9. The single-walled carbon nanotube fiber material obtained by the preparation method according to claim 8.

10. The single-walled carbon nanotube fiber material according to claim 9, characterized in that: The diameter of the single-walled carbon nanotube fiber material is 0.01 to 1.50 mm; And / or, the tensile strength of the single-walled carbon nanotube fiber material is 1.0 to 2.6 GPa.

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