High-crystallinity and small-diameter carbon nanotube fiber as well as preparation method and application thereof

Abstract

The invention discloses a high-crystallinity and small-diameter carbon nanotube fiber as well as a preparation method and application thereof. The carbon nanotube fiber with high crystallinity and small diameter is formed by assembling a high-purity single-wall carbon nanotube and a multi-wall carbon nanotube. The preparation method comprises the following steps: uniformly mixing a carbon source, a catalyst, an accelerant and water to obtain a precursor solution; under the action of a catalyst, introducing the precursor solution, inert gas and hydrogen into a reaction chamber, so that the carbon nanotubes grow and are formed on the surface of the catalyst, and are gathered and assembled into a sleeve-shaped aerogel structure in the reaction chamber; introducing the mixture into a liquid phase system to enable the mixture to be compactly shrunk into wet fibers, and collecting the wet fibers through an ultrahigh-rotating-speed winding device; and drying. The carbon nanotube fibers with high crystallinity and small diameter are prepared by realizing high-speed collection of the carbon nanotube fibers, and the carbon nanotube fibers have excellent electrical conductivity and mechanical properties and are suitable for the fields of high-performance wires and composite material reinforcements.

Description

Technical Field

[0001] The invention relates to a carbon nanotube fiber, in particular to a carbon nanotube fiber with high crystallinity and small diameter and a preparation method and application thereof, belonging to the technical field of nano material preparation. Background Art

[0002] Carbon nanotubes (CNT) have become a research hotspot in the field of materials science in recent years due to their unique structure and excellent performance. As a carbon material with a one-dimensional nanostructure, carbon nanotubes have significant advantages in electrical conductivity, thermal conductivity, and mechanical properties. As a three-dimensional assembly of carbon nanotubes, carbon nanotube fibers also have excellent properties, including high electrical conductivity, high thermal conductivity, and excellent mechanical properties. Therefore, carbon nanotube fibers have become candidates for high-performance materials and can be widely used in the fields of conductive materials and composite materials.

[0003] However, the existing preparation technology of carbon nanotube fibers still faces many limitations, especially in high-performance application scenarios, the material properties are difficult to fully meet the actual needs. In the current preparation technology, the crystallinity of carbon nanotubes is low and the degree of graphitization is insufficient, resulting in limited conductivity and mechanical properties of the fibers. In addition, carbon nanotubes often exist in the form of disordered stacking in the fibers, the fiber diameter is large and the uniformity is poor, and it is difficult to achieve the preparation of small diameter, high crystallinity fibers. These problems limit the wide application of carbon nanotube fibers in precision devices, aerospace and other high-performance fields. At the same time, the production efficiency of the existing process is low and cannot meet the needs of large-scale industrial production. Especially in the fields of wires and composite reinforcements, the requirements for the comprehensive performance of materials are high, and the performance of traditional carbon nanotube fibers is still significantly insufficient. Therefore, there is an urgent need for a new preparation method that can effectively improve the crystallinity and orientation of carbon nanotube fibers, significantly improve their conductivity and mechanical properties, and simultaneously achieve precise control of fiber diameter and improve production efficiency. Summary of the invention

[0004] The main purpose of the present invention is to provide a high crystallinity, small diameter carbon nanotube fiber and a preparation method thereof, so as to overcome the shortcomings of the prior art.

[0005] Another object of the present invention is to provide applications of the high crystallinity, small diameter carbon nanotube fibers.

[0006] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention includes: The embodiment of the present invention provides a high crystallinity, small diameter carbon nanotube fiber, which is assembled from high purity single-walled carbon nanotubes and multi-walled carbon nanotubes, wherein the diameter of the high crystallinity, small diameter carbon nanotube fiber is 5-20 μm, and the diameter of the high crystallinity, small diameter carbon nanotube fiber is 1 ... G / I D5~20.

[0007] In some embodiments, the conductivity of the high crystallinity, small diameter carbon nanotube fiber is 1 to 5×10 6 S / m, tensile strength is 3~5 GPa, and Young's modulus is 150~230 GPa.

[0008] The present invention also provides a method for preparing high-crystallinity, small-diameter carbon nanotube fibers, which comprises: Mixing the carbon source, the catalyst, the accelerator and water uniformly to obtain a precursor solution; Under the action of the catalyst, the precursor solution, inert gas and hydrogen are introduced into the reaction chamber together, so that the carbon nanotubes grow and form on the catalyst surface, and gather and assemble into a "sleeve"-shaped aerogel structure in the reaction chamber; The "sleeve"-shaped aerogel structure is introduced into a liquid phase system, and the "sleeve"-shaped aerogel structure is compactly shrunk into wet fibers by utilizing the interface effect of the solution, and the wet fibers are collected by an ultra-high speed winding device; The collected wet fibers are dried to obtain carbon nanotube fibers with high crystallinity and small diameter.

[0009] The embodiment of the present invention also provides carbon nanotube fibers with high crystallinity and small diameter prepared by the above preparation method.

[0010] The embodiment of the present invention also provides the use of the high crystallinity, small diameter carbon nanotube fiber in the preparation of wires or composite material reinforcements.

[0011] Compared with the prior art, the present invention has at least the following beneficial effects: (1) The present invention achieves high-rate fiber collection and then optimizes the orientation and crystallinity of carbon nanotube fibers to prepare high-crystallinity, small-diameter carbon nanotube fibers, which greatly improves the electrical conductivity and mechanical properties of carbon nanotube fibers. Compared with the traditional floating catalytic method for preparing carbon nanotube fibers, the present invention has the advantages of precise control of fiber diameter and improved mechanical properties and electrical conductivity, and can also greatly improve production efficiency. It is a universal method for preparing high-performance carbon nanotube fibers; (2) The high crystallinity and small diameter carbon nanotube fibers prepared by the present invention have high electrical conductivity and tensile strength, are dense inside and have small porosity, and can be effectively used in lightweight conductors and aerospace composite materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] 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.

[0013] Figure 1 is a cross-sectional SEM image of a high crystallinity, small diameter carbon nanotube fiber in a typical embodiment of the present invention; Figure 2 is a Raman data diagram of a high crystallinity, small diameter carbon nanotube fiber in a typical embodiment of the present invention; Figure 3 is a surface SEM image of a high crystallinity, small diameter carbon nanotube fiber in a typical embodiment of the present invention; Figure 4 This is an XPS data chart of a high crystallinity, small diameter carbon nanotube fiber C1s in a typical embodiment of the present invention. DETAILED DESCRIPTION

[0014] In view of the fact that the prior art has low crystallinity of carbon nanotubes, insufficient graphitization, and poor orientation of carbon nanotubes in fibers, which leads to limited conductivity and mechanical properties of fibers, the inventor of this case has proposed the technical solution of the present invention after long-term research and extensive practice, which mainly improves the orientation and crystallinity of fibers by increasing the collection rate, and prepares high crystallinity, small diameter carbon nanotube fibers. The technical solution, its implementation process and principle, etc. will be further explained as follows, but it cannot be understood as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made to the present invention by technicians in this field based on the content of the present invention still fall within the scope of protection of the present invention.

[0015] The high crystallinity of carbon nanotubes is usually manifested as a tighter and more orderly arrangement between carbon nanotubes, and a more regular arrangement of the graphite layer of the tube wall. Crystallinity has an important influence on the performance of carbon nanotube fibers. The present invention optimizes the orientation and crystallinity of carbon nanotube fibers by increasing the fiber collection rate, prepares high-crystallinity, small-diameter carbon nanotube fibers, and greatly improves the electrical conductivity and mechanical properties of carbon nanotube fibers. Compared with the traditional floating catalytic method for preparing carbon nanotube fibers, it has the advantages of precise control of fiber diameter and improved mechanical properties and electrical conductivity, and can also achieve a significant improvement in production efficiency. It is a universal method for preparing high-performance carbon nanotube fibers, which can be effectively applied to the development of lightweight conductors and aerospace composite materials technology.

[0016] As one aspect of the technical solution of the present invention, it provides a high crystallinity, small diameter carbon nanotube fiber, which is assembled from high-purity single-walled carbon nanotubes and multi-walled carbon nanotubes, and has the characteristics of high orientation, ultra-high crystallinity and small diameter.

[0017] In some embodiments, the diameter of the high crystallinity, small diameter carbon nanotube fibers ranges from 5 to 20 μm, preferably from 5 to 15 μm.

[0018] In some embodiments, the high crystallinity, small diameter carbon nanotube fibers have a G / I D 5~20.

[0019] In some embodiments, the density of the high crystallinity, small diameter carbon nanotube fibers can reach 1.5-2.0 g / cm 3 .

[0020] In some embodiments, the conductivity of the high crystallinity, small diameter carbon nanotube fiber is 1 to 5×10 6 S / m, tensile strength is 3~5 GPa, and Young's modulus is 150~230 GPa.

[0021] As another aspect of the technical solution of the present invention, a method for preparing a high-crystallinity, small-diameter carbon nanotube fiber is provided, comprising: Mixing the carbon source, the catalyst, the accelerator and water uniformly to obtain a precursor solution; Under the action of the catalyst, the precursor solution, inert gas and hydrogen are introduced into the reaction chamber together, so that the carbon nanotubes grow and form on the catalyst surface, and gather and assemble into a "sleeve"-shaped aerogel structure in the reaction chamber; The "sleeve"-shaped aerogel structure is introduced into a liquid phase system, and the "sleeve"-shaped aerogel structure is compactly shrunk into wet fibers by utilizing the interface effect of the solution, and the wet fibers are collected by an ultra-high speed winding device; The collected wet fibers are dried to obtain carbon nanotube fibers with high crystallinity and small diameter.

[0022] In some embodiments, the carbon source comprises a combination of ethanol and acetone.

[0023] In some preferred embodiments, the volume ratio of ethanol to acetone is 1:20 to 1:1.

[0024] Furthermore, the total amount of the carbon source is 100-120 ml.

[0025] In some embodiments, the catalyst includes ferrocene, but is not limited thereto.

[0026] In some embodiments, the promoter includes, but is not limited to, thiophene.

[0027] In some embodiments, the preparation method may specifically include: uniformly mixing a carbon source (ethanol and acetone), a catalyst (ferrocene), a promoter (thiophene) and a small amount of water in a certain proportion to obtain a precursor solution.

[0028] In some preferred embodiments, the volume ratio of the catalyst to the carbon source is 1:200 to 1:160.

[0029] In some preferred embodiments, the volume ratio of the promoter to the catalyst ferrocene is 3:1 to 4:1.

[0030] In some preferred embodiments, the volume ratio of water to carbon source is 1:12 to 1:4.

[0031] In some embodiments, the preparation method may specifically include: First, nitrogen is introduced into the high temperature reaction chamber to exclude air; The precursor solution is then introduced into the reaction chamber of a high-temperature reaction device together with an inert gas and hydrogen. Under the action of the catalyst, carbon nanotubes grow and take shape on the catalyst surface. After reacting for 10 to 30 seconds, the carbon nanotubes gather and assemble into a "sleeve"-shaped aerogel structure in the reaction chamber.

[0032] Furthermore, the inert gas includes argon, but is not limited thereto.

[0033] In some preferred embodiments, the preparation method specifically includes: introducing nitrogen into the reaction furnace to exhaust the air, and then introducing the precursor solution together with argon and hydrogen into the high-temperature reaction furnace. Under the action of the catalyst, the carbon nanotubes grow and take shape on the catalyst surface, and then gather and assemble into a "sleeve"-shaped aerogel structure at the tail of the reaction furnace.

[0034] In some preferred embodiments, the flow rate of the nitrogen is 3-5 SLM, and the process of introducing nitrogen and exhausting air takes 20-40 minutes.

[0035] In some preferred embodiments, the rate of introducing the precursor solution into the reaction chamber is 15-40 ml / h.

[0036] In some preferred embodiments, the total flow rate of the inert gas (argon) and hydrogen is 5-7 SLM.

[0037] In some preferred embodiments, the flow ratio of the inert gas (argon) to hydrogen is 1:1.5~1:1.

[0038] In some embodiments, the temperature of the reaction chamber is 1200-1400° C., and the reaction time is 10-30 s.

[0039] Furthermore, the furnace tube of the high temperature reaction equipment is made of alumina.

[0040] In some embodiments, the preparation method specifically includes: introducing a "sleeve"-shaped aerogel structure into a liquid phase system, utilizing the interfacial action of the solution to compactly shrink the aerogel structure into wet fibers, and collecting the wet fibers by an ultra-high speed winding device.

[0041] In some preferred embodiments, the liquid phase system is water.

[0042] In some preferred embodiments, the ultra-high speed of the ultra-high speed winding device is 60-90 m / min.

[0043] In some preferred embodiments, the ultra-high speed winding device further includes a set of auxiliary wheel devices with the same frequency in the water tank.

[0044] The present invention improves the fiber collection rate and thus optimizes the orientation and crystallinity of carbon nanotube fibers. Compared with the traditional floating catalytic method for preparing carbon nanotube fibers, the present invention has the advantages of precise control of fiber diameter and improved mechanical properties and conductivity, thereby preparing high crystallinity, small diameter carbon nanotube fibers.

[0045] In some embodiments, the preparation method may specifically include: drying the collected wet fibers to obtain the high crystallinity, small diameter carbon nanotube fibers.

[0046] In some preferred embodiments, the drying temperature is 180-300° C., and the drying time is 30-60 min.

[0047] In some preferred embodiments, the drying rate is 0.5-1 m / min.

[0048] Among them, in some more specific embodiments, the method for preparing the high crystallinity and small diameter carbon nanotube fiber comprises the following steps: The carbon source (ethanol and acetone), the catalyst (ferrocene), the promoter (thiophene) and a small amount of water are mixed uniformly in a certain proportion to obtain a precursor solution; Nitrogen is introduced into the reactor to exhaust the air, and then the precursor solution is introduced into the high-temperature reactor together with a certain flow of argon and hydrogen. Under the action of the catalyst, carbon nanotubes grow and take shape on the catalyst surface, and then gather and assemble into a "sleeve"-shaped aerogel structure at the tail of the reactor; The "sleeve"-shaped aerogel structure is introduced into a solution (water), and the interface effect of the solution is used to compactly shrink the aerogel structure into wet fibers, and the wet fibers are collected by an ultra-high speed winding device; The wet fiber is dried to obtain carbon nanotube fiber.

[0049] In some more specific embodiments, the preparation method specifically comprises: The total amount of the carbon source is 100-120 ml, wherein the volume ratio of ethanol to acetone is 1:20-1:1, the total amount of the catalyst ferrocene is 0.5-1 g, the volume ratio of the promoter thiophene to the catalyst ferrocene is 3:1-4:1, and the volume ratio of water to the carbon source is 1:12-1:4. The above are mixed evenly, and the mixing is ensured to be evenly carried out by ultrasound for more than 30 minutes to obtain a precursor solution; Nitrogen is introduced into the reactor body at a flow rate of 3-5 SLM to exhaust the air. The exhaust process takes 20-40 minutes. Then, the precursor solution is introduced into the alumina reactor tube at a high temperature of 1200-1400 °C together with argon and hydrogen. The injection rate of the precursor solution is 15-40 ml / h, the total flow rate of argon and hydrogen is 5-7 SLM, and the flow ratio of argon to hydrogen is 1:1.5-1:1. Under the action of the catalyst, carbon nanotubes grow and form on the catalyst surface, and then gather and assemble into a "sleeve" aerogel structure at the tail of the reactor. The "sleeve"-shaped aerogel structure is introduced into water, and the aerogel structure is compacted and shrunk into wet fibers by utilizing the interfacial effect of water, and the wet fibers are collected at a high speed of 60-90 m / min; The wet fiber is dried at a drying rate of 0.5 to 1 m / min and a drying temperature of 180 to 300° C. for 30 to 60 min, thereby obtaining a final carbon nanotube fiber with high crystallinity and small diameter.

[0050] As another aspect of the technical solution of the present invention, there is provided a carbon nanotube fiber with high crystallinity and small diameter prepared by the above-mentioned preparation method.

[0051] As another aspect of the technical solution of the present invention, the excellent performance of the aforementioned carbon nanotube fiber is also provided, and its conductivity is as high as 1~5×10 6 S / m, tensile strength is 3~5 GPa, and Young's modulus is 150~230 GPa.

[0052] The high crystallinity and small diameter carbon nanotube fibers prepared by the present invention are successfully prepared by improving the fiber collection rate to optimize the orientation and crystallinity of the carbon nanotube fibers, and the electrical conductivity and mechanical properties of the carbon nanotube fibers are greatly improved.

[0053] Moreover, the high crystallinity, small diameter carbon nanotube fibers prepared by the ultra-high collection rate adopted in the present invention have dense interiors and better uniformity than fibers prepared by traditional methods. In addition, this method can achieve precise control of fiber diameter and greatly improve production efficiency.

[0054] As another aspect of the technical solution of the present invention, it also relates to the application of the aforementioned high crystallinity, small diameter carbon nanotube fibers in high-performance wires or composite material reinforcements.

[0055] Furthermore, the applications include applications in lightweight wires, aerospace composite materials, or high-performance protective materials.

[0056] In summary, the present invention improves the fiber collection rate to optimize the orientation and crystallinity of carbon nanotube fibers, prepares high-crystallinity, small-diameter carbon nanotube fibers, greatly improves the electrical conductivity and mechanical properties of carbon nanotube fibers, and has the advantages of precise control of fiber diameter and improved mechanical properties and electrical conductivity compared to the traditional floating catalytic method for preparing carbon nanotube fibers, and can also greatly improve production efficiency. The prepared high-crystallinity, small-diameter carbon nanotube fibers have excellent electrical conductivity and high tensile strength. These characteristics enable the above-mentioned carbon nanotube fibers to be used in high-performance wires and composite reinforcements, including applications in lightweight wires, aerospace composites, or high-performance protective materials.

[0057] In order to make the purpose, technical scheme and advantages of the present invention clearer, the technical scheme of the present invention is further described in detail below in conjunction with the accompanying drawings and several preferred embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the present invention. For the test methods in the following embodiments that do not specify specific conditions, the test methods in the embodiments are all carried out under normal conditions. In addition, the technical features involved in each embodiment of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0058] Example 1 The total amount of carbon source prepared is 120 ml, which contains ethanol and acetone, the content of ethanol is 20 ml, the content of acetone is 100 ml, the total amount of catalyst ferrocene is 0.8 g, the total amount of promoter thiophene is 2.5 ml, and 30 ml of water is added. Ultrasonication is performed for more than 30 minutes to ensure uniform mixing to obtain a precursor solution. Nitrogen is introduced into the reactor body at a flow rate of 5 SLM to exhaust the air, and the air is exhausted for 40 minutes. Then the precursor solution is introduced into the alumina reactor tube at a high temperature of 1400 ℃ together with argon and hydrogen. The injection rate of the precursor solution is 30 ml / h, and the total flow rate of argon and hydrogen is 5 SLM, of which the flow rate of argon is 2.2 SLM and the flow rate of hydrogen is 2.8 SLM. Under the action of the catalyst, carbon nanotubes grow and form on the catalyst surface, and then gather and assemble into a "sleeve" aerogel structure at the tail of the reactor. The "sleeve" aerogel structure was introduced into water, and the interfacial effect of water was used to shrink the aerogel structure into wet fibers. The wet fibers were collected at a high speed of 90 m / min. The wet fibers were dried at a drying rate of 0.5 m / min and a drying temperature of 180 °C for 60 min to obtain the final carbon nanotube fibers. The fibers were subjected to Raman testing to obtain I G / I D The data are used to illustrate the degree of crystallinity. The fiber surface is observed by SEM to measure the fiber diameter. The fiber resistance is measured by a DC resistance tester to calculate the conductivity. The tensile strength of the fiber is measured by a universal testing machine. The test results are shown in Table 1.

[0059] Example 2 The total amount of carbon source prepared is 120 ml, which contains ethanol and acetone, the content of ethanol is 20 ml, the content of acetone is 100 ml, the total amount of catalyst ferrocene is 0.8 g, the total amount of promoter thiophene is 2.5 ml, and 30 ml of water is added. Ultrasonication is performed for more than 30 minutes to ensure uniform mixing to obtain a precursor solution. Nitrogen is introduced into the reactor body at a flow rate of 5 SLM to exhaust the air, and the air is exhausted for 40 minutes. Then the precursor solution is introduced into the alumina reactor tube at a high temperature of 1400 ℃ together with argon and hydrogen. The injection rate of the precursor solution is 30 ml / h, and the total flow rate of argon and hydrogen is 5 SLM, of which the flow rate of argon is 2.2 SLM and the flow rate of hydrogen is 2.8 SLM. Under the action of the catalyst, carbon nanotubes grow and form on the catalyst surface, and then gather and assemble into a "sleeve" aerogel structure at the tail of the reactor. The "sleeve" aerogel structure was introduced into water, and the interfacial effect of water was used to shrink the aerogel structure into wet fibers. The wet fibers were collected at a high speed of 85 m / min. The wet fibers were dried at a drying rate of 0.5 m / min and a drying temperature of 180 °C for 60 min to obtain the final carbon nanotube fibers. The fibers were subjected to Raman testing to obtain I G / I D The data are used to illustrate the degree of crystallinity. The fiber surface is observed by SEM to measure the fiber diameter. The fiber resistance is measured by a DC resistance tester to calculate the conductivity. The tensile strength of the fiber is measured by a universal testing machine. The test results are shown in Table 1.

[0060] Example 3 The total amount of carbon source prepared is 120 ml, which contains ethanol and acetone, the content of ethanol is 20 ml, the content of acetone is 100 ml, the total amount of catalyst ferrocene is 0.8 g, the total amount of promoter thiophene is 2.5 ml, and 30 ml of water is added. Ultrasonication is performed for more than 30 minutes to ensure uniform mixing to obtain a precursor solution. Nitrogen is introduced into the reactor body at a flow rate of 5 SLM to exhaust the air, and the air is exhausted for 40 minutes. Then the precursor solution is introduced into the alumina reactor tube at a high temperature of 1400 ℃ together with argon and hydrogen. The injection rate of the precursor solution is 30 ml / h, and the total flow rate of argon and hydrogen is 5 SLM, of which the flow rate of argon is 2.2 SLM and the flow rate of hydrogen is 2.8 SLM. Under the action of the catalyst, carbon nanotubes grow and form on the catalyst surface, and then gather and assemble into a "sleeve" aerogel structure at the tail of the reactor. The "sleeve" aerogel structure was introduced into water, and the interfacial effect of water was used to shrink the aerogel structure into wet fibers. The wet fibers were collected at 80 m / min. The wet fibers were dried at a drying rate of 0.5 m / min and a drying temperature of 180 °C for 60 min to obtain the final carbon nanotube fibers. The fibers were subjected to Raman testing to obtain I G / I D The data are used to illustrate the degree of crystallinity. The fiber surface is observed by SEM to measure the fiber diameter. The fiber resistance is measured by a DC resistance tester to calculate the conductivity. The tensile strength of the fiber is measured by a universal testing machine. The test results are shown in Table 1.

[0061] Example 4 The total amount of carbon source prepared is 120 ml, which contains ethanol and acetone, the content of ethanol is 20 ml, the content of acetone is 100 ml, the total amount of catalyst ferrocene is 0.8 g, the total amount of promoter thiophene is 2.5 ml, and 30 ml of water is added. Ultrasonication is performed for more than 30 minutes to ensure uniform mixing to obtain a precursor solution. Nitrogen is introduced into the reactor body at a flow rate of 5 SLM to exhaust the air, and the air is exhausted for 40 minutes. Then the precursor solution is introduced into the alumina reactor tube at a high temperature of 1400 ℃ together with argon and hydrogen. The injection rate of the precursor solution is 30 ml / h, and the total flow rate of argon and hydrogen is 5 SLM, of which the flow rate of argon is 2.2 SLM and the flow rate of hydrogen is 2.8 SLM. Under the action of the catalyst, carbon nanotubes grow and form on the catalyst surface, and then gather and assemble into a "sleeve" aerogel structure at the tail of the reactor. The "sleeve" aerogel structure was introduced into water, and the interfacial effect of water was used to shrink the aerogel structure into wet fibers. The wet fibers were collected at 75 m / min. The wet fibers were dried at a drying rate of 0.5 m / min and a drying temperature of 180 °C for 60 min to obtain the final carbon nanotube fibers. The fibers were subjected to Raman testing to obtain IG / I D The data are used to illustrate the degree of crystallinity. The fiber surface is observed by SEM to measure the fiber diameter. The fiber resistance is measured by a DC resistance tester to calculate the conductivity. The tensile strength of the fiber is measured by a universal testing machine. The test results are shown in Table 1.

[0062] Example 5 The total amount of carbon source prepared is 120 ml, which contains ethanol and acetone, the content of ethanol is 20 ml, the content of acetone is 100 ml, the total amount of catalyst ferrocene is 0.8 g, the total amount of promoter thiophene is 2.5 ml, and 30 ml of water is added. Ultrasonication is performed for more than 30 minutes to ensure uniform mixing to obtain a precursor solution. Nitrogen is introduced into the reactor body at a flow rate of 5 SLM to exhaust the air, and the air is exhausted for 40 minutes. Then the precursor solution is introduced into the alumina reactor tube at a high temperature of 1400 ℃ together with argon and hydrogen. The injection rate of the precursor solution is 30 ml / h, and the total flow rate of argon and hydrogen is 5 SLM, of which the flow rate of argon is 2.2 SLM and the flow rate of hydrogen is 2.8 SLM. Under the action of the catalyst, carbon nanotubes grow and form on the catalyst surface, and then gather and assemble into a "sleeve" aerogel structure at the tail of the reactor. The "sleeve" aerogel structure was introduced into water, and the interfacial effect of water was used to shrink the aerogel structure into wet fibers. The wet fibers were collected at 70 m / min. The wet fibers were dried at a drying rate of 0.5 m / min and a drying temperature of 180 °C for 60 min to obtain the final carbon nanotube fibers. The fibers were subjected to Raman testing to obtain I G / I D The data are used to illustrate the degree of crystallinity. The fiber surface is observed by SEM to measure the fiber diameter. The fiber resistance is measured by a DC resistance tester to calculate the conductivity. The tensile strength of the fiber is measured by a universal testing machine. The test results are shown in Table 1.

[0063] Example 6 The total amount of carbon source prepared is 120 ml, which contains ethanol and acetone, the content of ethanol is 20 ml, the content of acetone is 100 ml, the total amount of catalyst ferrocene is 0.8 g, the total amount of promoter thiophene is 2.5 ml, and 30 ml of water is added. Ultrasonication is performed for more than 30 minutes to ensure uniform mixing to obtain a precursor solution. Nitrogen is introduced into the reactor body at a flow rate of 5 SLM to exhaust the air, and the air is exhausted for 40 minutes. Then the precursor solution is introduced into the alumina reactor tube at a high temperature of 1400 ℃ together with argon and hydrogen. The injection rate of the precursor solution is 30 ml / h, and the total flow rate of argon and hydrogen is 5 SLM, of which the flow rate of argon is 2.2 SLM and the flow rate of hydrogen is 2.8 SLM. Under the action of the catalyst, carbon nanotubes grow and form on the catalyst surface, and then gather and assemble into a "sleeve" aerogel structure at the tail of the reactor. The "sleeve" aerogel structure was introduced into water, and the interfacial effect of water was used to shrink the aerogel structure into wet fibers. The wet fibers were collected at 65 m / min. The wet fibers were dried at a drying rate of 0.5 m / min and a drying temperature of 180 °C for 60 min to obtain the final carbon nanotube fibers. The fibers were subjected to Raman testing to obtain I G / I D The data are used to illustrate the degree of crystallinity. The fiber surface is observed by SEM to measure the fiber diameter. The fiber resistance is measured by a DC resistance tester to calculate the conductivity. The tensile strength of the fiber is measured by a universal testing machine. The test results are shown in Table 1.

[0064] Example 7 The total amount of carbon source prepared is 120 ml, which contains ethanol and acetone, the content of ethanol is 20 ml, the content of acetone is 100 ml, the total amount of catalyst ferrocene is 0.8 g, the total amount of promoter thiophene is 2.5 ml, and 30 ml of water is added. Ultrasonication is performed for more than 30 minutes to ensure uniform mixing to obtain a precursor solution. Nitrogen is introduced into the reactor body at a flow rate of 5 SLM to exhaust the air, and the air is exhausted for 40 minutes. Then the precursor solution is introduced into the alumina reactor tube at a high temperature of 1400 ℃ together with argon and hydrogen. The injection rate of the precursor solution is 30 ml / h, and the total flow rate of argon and hydrogen is 5 SLM, of which the flow rate of argon is 2.2 SLM and the flow rate of hydrogen is 2.8 SLM. Under the action of the catalyst, carbon nanotubes grow and form on the catalyst surface, and then gather and assemble into a "sleeve" aerogel structure at the tail of the reactor. The "sleeve" aerogel structure was introduced into water, and the interfacial effect of water was used to shrink the aerogel structure into wet fibers. The wet fibers were collected at 60 m / min. The wet fibers were dried at a drying rate of 0.5 m / min and a drying temperature of 180 °C for 60 min to obtain the final carbon nanotube fibers. The fibers were subjected to Raman testing to obtain IG / I D The data are used to illustrate the degree of crystallinity. The fiber surface is observed by SEM to measure the fiber diameter. The fiber resistance is measured by a DC resistance tester to calculate the conductivity. The tensile strength of the fiber is measured by a universal testing machine. The test results are shown in Table 1.

[0065] Example 8 The total amount of the carbon source is 120 ml, which contains ethanol and acetone, the content of ethanol is 60 ml, the content of acetone is 60 ml, the volume ratio of the catalyst ferrocene to the carbon source is 1:200, the volume ratio of the promoter thiophene to the catalyst is 3:1, and 30 ml of water is added. Ultrasonication is performed for more than 30 minutes to ensure uniform mixing to obtain a precursor solution. Nitrogen is introduced into the reactor body at a flow rate of 3 SLM to exhaust the air, and the air is exhausted for 30 minutes. Then, the precursor solution is introduced into the alumina reactor tube at a high temperature of 1200 ℃ together with argon and hydrogen. The injection rate of the precursor solution is 40 ml / h, and the total flow rate of argon and hydrogen is 7 SLM, wherein the flow ratio of argon to hydrogen is 1:1.5. Under the action of the catalyst, carbon nanotubes grow and form on the catalyst surface, and after 30 seconds of reaction, they are assembled into a "sleeve" aerogel structure at the tail of the reactor. The "sleeve" aerogel structure was introduced into water, and the interfacial effect of water was used to shrink the aerogel structure into wet fibers. The wet fibers were collected at a high speed of 90 m / min. The wet fibers were dried at a drying rate of 1 m / min and a drying temperature of 300 °C for 30 minutes to obtain the final carbon nanotube fibers.

[0066] Example 9 The total amount of the prepared carbon source is 210 ml, which contains ethanol and acetone, the content of ethanol is 10 ml, the content of acetone is 200 ml, the volume ratio of the catalyst ferrocene to the carbon source is 1:160, the volume ratio of the promoter thiophene to the catalyst is 4:1, and 17.5 ml of water is added. Ultrasonication is performed for more than 30 minutes to ensure uniform mixing to obtain a precursor solution. Nitrogen is introduced into the reactor body at a flow rate of 4 SLM to exhaust the air, and the air is exhausted for 20 minutes. Then, the precursor solution is introduced into the alumina reactor tube at a high temperature of 1300 ℃ together with argon and hydrogen. The injection rate of the precursor solution is 15 ml / h, and the total flow rate of argon and hydrogen is 6 SLM, of which the flow rate of argon is 3 SLM and the flow rate of hydrogen is 3 SLM. Under the action of the catalyst, carbon nanotubes grow and form on the catalyst surface, and after reacting for 10 seconds, they are assembled into a "sleeve" aerogel structure at the tail of the reactor. The "sleeve" aerogel structure was introduced into water, and the interfacial effect of water was used to shrink the aerogel structure into wet fibers. The wet fibers were collected at a high speed of 90 m / min. The wet fibers were dried at a drying rate of 0.8 m / min and a drying temperature of 240 °C for 40 min to obtain the final carbon nanotube fibers.

[0067] Comparative Example 1 The total amount of carbon source prepared is 120 ml, which contains ethanol and acetone, the content of ethanol is 20 ml, the content of acetone is 100 ml, the total amount of catalyst ferrocene is 0.8 g, the total amount of promoter thiophene is 2.5 ml, and 30 ml of water is added. Ultrasonication is performed for more than 30 minutes to ensure uniform mixing to obtain a precursor solution. Nitrogen is introduced into the reactor body at a flow rate of 5 SLM to exhaust the air, and the air is exhausted for 40 minutes. Then the precursor solution is introduced into the alumina reactor tube at a high temperature of 1400 ℃ together with argon and hydrogen. The injection rate of the precursor solution is 30 ml / h, and the total flow rate of argon and hydrogen is 5 SLM, of which the flow rate of argon is 2.2 SLM and the flow rate of hydrogen is 2.8 SLM. Under the action of the catalyst, carbon nanotubes grow and form on the catalyst surface, and then gather and assemble into a "sleeve" aerogel structure at the tail of the reactor. The "sleeve" aerogel structure was introduced into water, and the interfacial effect of water was used to shrink the aerogel structure into wet fibers. The wet fibers were collected at a speed of 20 m / min. The wet fibers were dried at a drying rate of 0.5 m / min and a drying temperature of 180 °C to obtain the final carbon nanotube fibers. The fibers were subjected to Raman testing to obtain I G / I D The data are used to illustrate the degree of crystallinity. The fiber surface is observed by SEM to measure the fiber diameter. The fiber resistance is measured by a DC resistance tester to calculate the conductivity. The tensile strength of the fiber is measured by a universal testing machine. The test results are shown in Table 1.

[0068] Comparative Example 2 The total amount of the carbon source is 120 ml, which contains ethanol and acetone, the content of ethanol is 20 ml, the content of acetone is 100 ml, the total amount of the catalyst ferrocene is 0.8 g, the total amount of the promoter thiophene is 2.5 ml, and 30 ml of water is added. Ultrasonication is performed for more than 30 minutes to ensure uniform mixing to obtain a precursor solution. Nitrogen is introduced into the reactor body at a flow rate of 5 SLM to exhaust the air, and the air is exhausted for 40 minutes. Then, the precursor solution is introduced into the alumina reactor tube at a high temperature of 1400 ℃ together with argon and hydrogen. The injection rate of the precursor solution is 20 ml / h, and the total flow rate of argon and hydrogen is 5 SLM, of which the flow rate of argon is 2.2 SLM and the flow rate of hydrogen is 2.8 SLM. Under the action of the catalyst, carbon nanotubes grow and form on the catalyst surface, and then gather and assemble into a "sleeve" aerogel structure at the tail of the reactor. The "sleeve" aerogel structure was introduced into water, and the interfacial effect of water was used to shrink the aerogel structure into wet fibers. The wet fibers were collected at a speed of 20 m / min. The wet fibers were dried at a drying rate of 0.5 m / min and a drying temperature of 180 °C to obtain the final carbon nanotube fibers. The fibers were subjected to Raman testing to obtain I G / I D The data are used to illustrate the degree of crystallinity. The fiber surface is observed by SEM to measure the fiber diameter. The fiber resistance is measured by a DC resistance tester to calculate the conductivity. The tensile strength of the fiber is measured by a universal testing machine. The test results are shown in Table 1.

[0069] Comparative Example 3 The total amount of carbon source prepared is 120 ml, which contains ethanol and acetone, the content of ethanol is 20 ml, the content of acetone is 100 ml, the total amount of catalyst ferrocene is 0.8 g, the total amount of promoter thiophene is 2.5 ml, and 30 ml of water is added. Ultrasonication is performed for more than 30 minutes to ensure uniform mixing to obtain a precursor solution. Nitrogen is introduced into the reactor body at a flow rate of 5 SLM to exhaust the air, and the air is exhausted for 40 minutes. Then the precursor solution is introduced into the alumina reactor tube at a high temperature of 1400 ℃ together with argon and hydrogen. The injection rate of the precursor solution is 10 ml / h, and the total flow rate of argon and hydrogen is 5 SLM, of which the flow rate of argon is 2.2 SLM and the flow rate of hydrogen is 2.8 SLM. Under the action of the catalyst, carbon nanotubes grow and form on the catalyst surface, and then gather and assemble into a "sleeve" aerogel structure at the tail of the reactor. The "sleeve" aerogel structure was introduced into water, and the interfacial effect of water was used to shrink the aerogel structure into wet fibers. The wet fibers were collected at a speed of 20 m / min. The wet fibers were dried at a drying rate of 0.5 m / min and a drying temperature of 180 °C to obtain the final carbon nanotube fibers. The fibers were subjected to Raman testing to obtain I G / I D The data are used to illustrate the degree of crystallinity. The fiber surface is observed by SEM to measure the fiber diameter. The fiber resistance is measured by a DC resistance tester to calculate the conductivity. The tensile strength of the fiber is measured by a universal testing machine. The test results are shown in Table 1.

[0070] Table 1 Data test results of carbon nanotube fibers obtained in Examples 1-9 and Comparative Examples 1-3

[0071] Furthermore, the high crystallinity, small diameter carbon nanotube fibers were cut using an ion beam, and cross-sectional SEM images were taken. Figure 1 As shown, the surface SEM image is Figure 3 As shown, it is shown that the ultra-high collection rate can make the fiber interior more dense, thereby improving the mechanical and electrical properties. Specifically, the Raman data of a high crystallinity, small diameter carbon nanotube fiber in a typical embodiment of the present invention is as follows: Figure 2 As shown in FIG. 1 , the XPS data of a high crystallinity, small diameter carbon nanotube fiber C1s in a typical embodiment is shown in FIG. Figure 4 shown.

[0072] 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.

[0073] The various aspects, embodiments, features and examples of the present invention should be considered to be illustrative in all aspects and are not intended to limit the present invention. The scope of the present invention is defined solely by the claims. Other embodiments, modifications and uses will be apparent to those skilled in the art without departing from the spirit and scope of the claimed invention.

[0074] Although the present invention has been described with reference to illustrative embodiments, it will be appreciated by those skilled in the art that various other changes, omissions and / or additions may be made without departing from the spirit and scope of the present invention and that the elements of the embodiments may be replaced by substantial equivalents. In addition, many modifications may be made without departing from the scope of the present invention to adapt specific circumstances or materials to the teachings of the present invention. Therefore, it is not intended herein to limit the present invention to the disclosed specific embodiments for performing the present invention, but it is intended that the present invention will include all embodiments within the scope of the appended claims. In addition, unless specifically stated, any use of the terms first, second, etc. does not indicate any order or importance, but rather uses the terms first, second, etc. to distinguish one element from another.

Claims

1. A high crystallinity, small diameter carbon nanotube fiber, characterized in that: The high crystallinity, small diameter carbon nanotube fiber is assembled from high purity single-walled carbon nanotubes and multi-walled carbon nanotubes, and the diameter of the high crystallinity, small diameter carbon nanotube fiber is 5 to 20 μm. G / I D 5~20.

2. The high crystallinity, small diameter carbon nanotube fiber according to claim 1, characterized in that: The diameter of the high crystallinity, small diameter carbon nanotube fiber is 5-20 μm; and / or the density of the high crystallinity, small diameter carbon nanotube fiber is 1.5-2.0 g / cm 3 .

3. The high crystallinity, small diameter carbon nanotube fiber according to claim 1, characterized in that: The conductivity of the high crystallinity and small diameter carbon nanotube fiber is 1-5×10 6 S / m, tensile strength is 3~5 GPa, and Young's modulus is 150~230GPa.

4. A method for preparing high crystallinity and small diameter carbon nanotube fibers, characterized in that: include: The carbon source, the catalyst, the accelerator and water are mixed uniformly to obtain a precursor solution; Under the action of the catalyst, the precursor solution, inert gas and hydrogen are introduced into the reaction chamber together, so that the carbon nanotubes grow and form on the catalyst surface, and gather and assemble into a "sleeve" aerogel structure in the reaction chamber; The "sleeve"-shaped aerogel structure is introduced into a liquid phase system, and the "sleeve"-shaped aerogel structure is compactly shrunk into wet fibers by utilizing the interface effect of the solution, and the wet fibers are collected by an ultra-high speed winding device; The collected wet fibers are dried to obtain carbon nanotube fibers with high crystallinity and small diameter.

5. The preparation method according to claim 4, characterized in that: The carbon source comprises a combination of ethanol and acetone; preferably, the volume ratio of ethanol to acetone is 1:20 to 1:1; and / or, the catalyst comprises ferrocene; and / or, the promoter comprises thiophene; And / or, the volume ratio of the catalyst to the carbon source is 1:200 to 1:160; And / or, the volume ratio of the promoter to the catalyst is 3:1 to 4:1; And / or, the volume ratio of water to carbon source is 1:12~1:

4.

6. The preparation method according to claim 4, characterized in that: include: First, nitrogen is introduced into the high temperature reaction chamber to exclude air; Then, the precursor solution, inert gas and hydrogen are introduced into the reaction chamber of the high-temperature reaction equipment. Under the action of the catalyst, the carbon nanotubes grow and form on the catalyst surface. After 10 to 30 seconds of reaction, the carbon nanotubes gather and assemble into a "sleeve"-shaped aerogel structure in the reaction chamber. Preferably, the flow rate of the nitrogen is 3-5 SLM, and the time for introducing the nitrogen is 20-40 min; Preferably, the rate of introducing the precursor solution into the reaction chamber is 15-40 ml / h; Preferably, the inert gas comprises argon; Preferably, the total flow rate of the inert gas and hydrogen is 5-7 SLM, Preferably, the flow ratio of the inert gas to hydrogen is 1:1.5~1:1; And / or, the temperature of the reaction chamber is 1200-1400°C, and the reaction time is 10-30 s; Preferably, the furnace tube of the high-temperature reaction equipment is made of alumina.

7. The preparation method according to claim 4, characterized in that: The liquid phase system includes water; and / or the speed of the ultra-high speed winding device is 60-90 m / min; Preferably, the ultra-high speed winding device also includes an auxiliary wheel device with the same frequency.

8. The preparation method according to claim 4, characterized in that: include: Drying the collected wet fibers to obtain the carbon nanotube fibers with high crystallinity and small diameter; Preferably, the drying temperature is 180-300°C and the drying time is 30-60 min; Preferably, the drying rate is 0.5-1 m / min.

9. Carbon nanotube fibers with high crystallinity and small diameter prepared by the preparation method according to any one of claims 4 to 8.

10. Use of the high crystallinity, small diameter carbon nanotube fiber according to any one of claims 1 to 3 and 9 in preparing a wire or a composite material reinforcement; preferably, the use comprises: The high crystallinity and small diameter carbon nanotube fibers are used in lightweight wires, aerospace composite materials or high-performance protective materials.

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