Graphitized carbon nanotube as well as preparation method and application thereof
High-performance graphitized carbon nanotubes were prepared by combining self-assembly and cryogenic freezing with a graphitization process. This solved the problems of non-renewable raw materials and high energy consumption in existing technologies, and enabled the simple preparation and excellent performance application of high aspect ratio nanotubes.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SOUTHWEST JIAOTONG UNIV
- Filing Date
- 2026-02-04
- Publication Date
- 2026-05-12
AI Technical Summary
Existing methods for preparing carbon nanotubes rely on carbon source gas and metal catalysts. The raw materials are non-renewable and the production process is energy-intensive, making it difficult to achieve simple and easy preparation of high-performance carbon nanotubes.
Graphitized carbon nanotubes are prepared by adding an electrolyte solution to deionized water using natural polymer or polymer raw materials, and through stirring, dialysis, freeze drying, carbonization and graphitization steps. Electrolytes are used to promote molecular self-assembly to form ordered nanotubes, which are then spun into fibers by wet spinning.
Graphitized carbon nanotubes with smooth surfaces, sealed ends, and high aspect ratios were prepared, exhibiting excellent electrical and thermal conductivity and high strength, making them suitable for aerospace, defense, and other fields.
Smart Images
Figure CN122010098A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of nanomaterials and fiber technology, specifically relating to a graphitized carbon nanotube, its preparation method, and its application. Background Technology
[0002] Carbon nanotubes, due to their superior mechanical, electrical, and thermal properties, can be assembled into continuous one-dimensional fibers from macroscopic quantities, making them a key pathway for applications in defense, aerospace, and flexible electronics. Currently, the main method for preparing carbon nanotubes is chemical vapor deposition (CVD), which involves passing a carbon source gas through the surface of a nanoscale metal catalyst at a medium temperature (500-1000℃). After the carbon source gas decomposes, carbon atoms dissolve and precipitate on the catalyst particles, growing carbon nanotubes. However, this method relies on the carbon source gas and metal catalyst, the raw materials are non-renewable, and the production process is energy-intensive.
[0003] Therefore, it is very meaningful to develop a method for obtaining carbon nanotubes with readily available raw materials, simple processing, and excellent performance. Summary of the Invention
[0004] To address the aforementioned shortcomings of existing technologies, the present invention aims to provide a graphitized carbon nanotube, its preparation method, and its application. This method is simple to implement and yields carbon nanotubes with excellent performance.
[0005] The technical solution adopted in this invention is as follows: A graphitized carbon nanotube, wherein the graphitized carbon nanotube has a graphite lattice stripe structure, a diameter of 400~900nm, a length up to the centimeter level, and a graphitization degree of up to 60~90%.
[0006] A method for preparing graphitized carbon nanotubes includes the following steps: Step 1. Dissolve the natural polymer raw material or polymeric polymer raw material in deionized water, and then add an electrolyte solution to obtain a precursor solution; in the precursor solution, the mass concentration of the natural polymer raw material or polymeric polymer raw material is 1-5 wt%, and the concentration of the electrolyte is 0.01-0.05 mol / L; Step 2. Stir the precursor solution obtained in Step 1, dialyze it, freeze-dry it, and obtain nanotubes; Step 3. The nanotubes obtained in Step 2 are sequentially carbonized and graphitized to obtain graphitized carbon nanotubes.
[0007] Furthermore, in step 1, the natural polymer raw materials are chitosan, sodium alginate, hydroxypropyl cellulose, hydroxyethyl cellulose, lignin, carboxymethyl-β-cyclodextrin, and sodium carboxymethyl cellulose; the polymer raw materials are polyacrylic acid, sodium polyacrylate, polyglycerol ester, polyvinylidene fluoride-hexafluorophosphate copolymer, and polyvinyl alcohol.
[0008] Furthermore, in step 1, the electrolyte is sodium chloride, sodium sulfate, sodium sulfite, silver nitrate, or copper chloride.
[0009] Furthermore, in step 1, when the raw materials are electrolytes such as sodium alginate, sodium carboxymethyl cellulose, and sodium polyacrylate, no electrolyte solution is introduced into the precursor solution, and the sodium ion concentration in the precursor solution is controlled at 0.01-0.05 mol / L.
[0010] Furthermore, in step 2, after stirring the precursor solution, it is dialyzed for 1-3 days, then fully frozen in a liquid nitrogen environment and freeze-dried to obtain nanotubes.
[0011] Furthermore, in step 3, the carbonization process is as follows: the nanotubes are placed in a tube furnace and heated to 200-300℃ at a rate of 2-5℃ / min under an inert gas atmosphere, and held for 0.5-3h; then the temperature is increased to 400-600℃ at a rate of 5-10℃ / min and held for 2-6h to complete the carbonization.
[0012] Furthermore, in step 3, the graphitization process is as follows: the carbonized nanotubes are placed in a graphitization furnace, and the temperature is adjusted to a range of 1600~2000℃ for 10s by pulse current; the process of "adjusting the temperature range of 1600~2000℃ for 10s by pulse current" is repeated 5~10 times to complete the graphitization.
[0013] Furthermore, the graphitized carbon nanotubes obtained in step 3 have a graphite lattice stripe structure.
[0014] A method for preparing nanotube fibers based on graphitized carbon nanotubes, wherein graphitized carbon nanotubes are formed into fibers with adjustable length and diameter through methods such as wet spinning.
[0015] A method for preparing nanotube fibers based on graphitized carbon nanotubes includes the following steps: Step 1. Mix graphitized carbon nanotubes and a surfactant in water, with the concentration of graphitized nanotubes in the mixture being 0.5~1 wt%. Step 2. After sonicating the obtained mixture at room temperature for 60 min, inject it into the coagulation bath through a needle at a rate of 0.1~0.5 cm / min; Step 3. After complete solidification, the graphitized nanotube fibers obtained by wet spinning are immersed in deionized water for 24 hours to remove residual surfactants; then, they are left overnight at ambient temperature to obtain the final graphitized nanotube fibers.
[0016] Furthermore, in step 1, the surfactant is sodium cholate, sodium dodecylbenzenesulfonate, etc.
[0017] Furthermore, in step 2, the coagulation bath is composed of isopropanol and water in a volume ratio of (1~4):1.
[0018] Furthermore, in step 2, the diameter of the needle is on the order of micrometers or millimeters.
[0019] This invention also provides applications of the above-mentioned graphitized carbon nanotubes in electromagnetic absorbing materials, high-performance composite materials, flexible electronic devices, etc.
[0020] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention provides a graphitized carbon nanotube and its preparation method. By adding an electrolyte with strong ionization properties, appropriate ion size, and a certain hydration capacity to a precursor solution, and during low-temperature freezing, the environment provided by the electrolyte and the precursor aqueous solution induces self-assembly of natural polymer molecules based on intermolecular forces, resulting in nanotubes with ordered molecular arrangement. The preparation method is simple, low-cost, and produces nanotubes with smooth surfaces, sealed ends, and, most importantly, a particularly excellent high aspect ratio.
[0021] 2. This invention provides a graphitized carbon nanotube with a graphite lattice stripe structure. The graphite lattice stripes correspond to a six-membered ring network composed of sp² hybridized carbon atoms. This structure implies that there are no structural defects inside the carbon nanotube, allowing full utilization of the inherent strength of carbon-carbon bonds. This enables the tensile strength of the carbon nanotube to approach the theoretical limit, making it suitable for applications in aerospace, defense, and other fields. Furthermore, each carbon atom in the graphite lattice has an unbonded π electron. These electrons can move freely in the highly delocalized conjugated system, resulting in electrical conductivity superior to most metals and carbon fibers. In addition, the graphite lattice endows the material with excellent thermal conductivity, thermal stability, and chemical stability.
[0022] 3. This invention provides a graphitized carbon nanotube and its preparation method. High aspect ratio nanotubes are formed through self-assembly, followed by carbonization and graphitization to obtain graphitized carbon nanotubes. The graphitized carbon nanotubes possess graphite lattice fringes, exhibiting high internal order, minimal defects, and extremely high crystallinity. This results in materials with ultra-high strength, ultra-high modulus, excellent electrical and thermal conductivity, and outstanding stability. Attached Figure Description
[0023] Figure 1 These are morphology images of chitosan nanotubes prepared in Example 1 at different magnifications; Figure 2 These are morphology images of chitosan nanotubes obtained in Example 2 at different magnifications; Figure 3 These are morphology images of sodium carboxymethyl cellulose nanotubes prepared in Example 3 at different magnifications; Figure 4 These are morphology images of sodium carboxymethyl cellulose nanotubes prepared in Example 4 at different magnifications. Figure 5 These are morphology images of the polyacrylic acid nanotubes prepared in Example 5 at different magnifications; Figure 6 These are morphology images of the polyacrylic acid nanotubes prepared in Example 6 at different magnifications; Figure 7 These are morphology images of sodium polyacrylate nanotubes prepared in Example 7 at different magnifications; Figure 8 These are morphology images of sodium polyacrylate nanotubes prepared in Example 8 at different magnifications; Figure 9 These are morphology images of the carboxymethyl-β-cyclodextrin nanotubes prepared in Example 9 at different magnifications; Figure 10 The images show the morphology of the hydroxypropyl cellulose nanotubes prepared in Example 10 at different magnifications. Figure 11 The images show the morphology of chitosan nanotubes prepared in Example 11 at different magnifications (b, c) and their diameter statistical distribution (d). Figure 12 The images shown are transmission electron microscope (TEM) images (a), high-resolution transmission electron microscope (HEM) images (b), and selected area electron diffraction (C) patterns of carbon nanotubes after graphitization treatment in Example 11. Figure 13 X-ray diffraction patterns of chitosan nanotubes, carbonized chitosan nanotubes, and graphitized chitosan nanotubes from Example 11. Figure 14 The Raman spectra of carbonized chitosan nanotubes and graphitized chitosan nanotubes in Example 11 are shown below. Figure 15 The images show the atomic force microscopy morphology of a single graphitized chitosan nanotube from Example 11 (a corresponds to two-dimensional morphology, b corresponds to three-dimensional morphology) and the measured compressive modulus (c). Figure 16 Scanning electron microscope (SEM) image of graphitized chitosan nanotube fibers; Figure 17Load-strain curve (a) and stress-strain curve (b) of a single graphitized chitosan nanotube fiber. Detailed Implementation
[0024] The examples given below are for illustrative purposes only and are not intended to limit the scope of the invention. Unless otherwise specified, conditions in the examples are performed under standard conditions or as recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified are all commercially available products.
[0025] A graphitized carbon nanotube is disclosed, wherein the graphitized carbon nanotube has a one-dimensional carbon fiber structure with a diameter of 400-900 nm and a length reaching the centimeter level, and a graphitization degree of 60-90%. Specifically, the length is related to the height of the container used in preparation and the height of the solution contained therein. The nanotube shell extends continuously along the direction of cold flow. For example, if a solution of 1-3 cm height is contained in a narrow-mouthed, long-necked, open-top bottle, the length of the obtained nanotube will be 1-3 cm. Example
[0026] A method for preparing chitosan nanotubes includes the following steps: 0.4 g of chitosan was added to 10 mL of water and stirred until no bubbles were observed. Then, 0.05 M NaCl was added and stirred until well mixed. The mixture was then dialyzed at room temperature for 72 h and lyophilized to obtain chitosan nanotubes. The corresponding morphology is shown in the figure below. Figure 1 As shown.
[0027] Depend on Figure 1 It can be seen that the chitosan nanotubes prepared by the above method have smooth surfaces, diameters ranging from 200 to 600 nm, and lengths exceeding 100 μm. Example
[0028] A method for preparing chitosan nanotubes includes the following steps: 0.4 g of chitosan was added to 10 mL of water and stirred until no bubbles appeared. Then, 0.01 M NaCl was added and stirred until well mixed. The mixture was then dialyzed at room temperature for 72 h and lyophilized to obtain chitosan nanotubes. The corresponding morphology is shown in the figure below. Figure 2 As shown.
[0029] Depend on Figure 2 It can be seen that the chitosan nanotubes prepared by the above method have smooth surfaces, diameters ranging from 200 to 600 nm, and lengths exceeding the SEM morphology observation range. Example
[0030] A method for preparing sodium carboxymethyl cellulose nanotubes includes the following steps: 0.4 g of sodium carboxymethyl cellulose (CMC) was mixed with 20 mL of water and stirred at 60 °C until no bubbles were observed. Then, 0.05 M NaCl was added and stirred for 1 h. Finally, the mixture was dialyzed at room temperature for 72 h and then lyophilized to obtain sodium carboxymethyl cellulose nanotubes. The corresponding morphology is shown in the figure below. Figure 3 As shown.
[0031] Depend on Figure 3 It can be seen that the sodium carboxymethyl cellulose nanotubes prepared by the above method have smooth surfaces, diameters ranging from 300 to 800 nm, and lengths exceeding the SEM morphology observation range. Example
[0032] A method for preparing sodium carboxymethyl cellulose nanotubes includes the following steps: 0.2 g of sodium carboxymethyl cellulose (CMC) was mixed with 20 mL of water and stirred at 60 °C until no bubbles were observed. Then, 0.01 M NaCl was added and stirred for 1 h. Finally, the mixture was dialyzed at room temperature for 72 h and then lyophilized to obtain sodium carboxymethyl cellulose nanotubes. The corresponding morphology is shown in the figure below. Figure 4 As shown.
[0033] Depend on Figure 4 It can be seen that the sodium carboxymethyl cellulose nanotubes prepared by the above method have smooth surfaces, diameters ranging from 300 to 800 nm, and lengths exceeding the SEM morphology observation range. Example
[0034] A method for preparing polyacrylic acid nanotubes includes the following steps: 0.4 g of polyacrylic acid (PAA) was mixed with 20 mL of water and stirred at 60 °C until no bubbles were observed. Then, 0.05 M NaCl was added and stirred for 1 h. Finally, the mixture was dialyzed at room temperature for 72 h and then lyophilized to obtain polyacrylic acid nanotubes. The corresponding morphology is shown in the figure below. Figure 5 As shown.
[0035] Depend on Figure 5 It can be seen that the polyacrylic acid nanotubes prepared by the above method have smooth surfaces, diameters ranging from 200 to 800 nm, and lengths exceeding the SEM morphology observation range. Example
[0036] A method for preparing polyacrylic acid nanotubes includes the following steps: 0.2 g of polyacrylic acid (PAA) was mixed with 20 mL of water and stirred overnight. Then, 0.05 M NaCl was added and stirred for 1 h. Finally, the mixture was dialyzed at room temperature for 72 h and then lyophilized to obtain polyacrylic acid nanotubes. The corresponding morphology is shown in the figure. Figure 6 As shown.
[0037] Depend on Figure 6It can be seen that the polyacrylic acid nanotubes prepared by the above method have smooth surfaces, diameters ranging from 200 to 800 nm, and lengths exceeding the SEM morphology observation range. Example
[0038] A method for preparing sodium polyacrylate nanotubes includes the following steps: 0.2 g of sodium polyacrylate (PAAS) was mixed with 20 mL of water and stirred until homogeneous. Then, 0.01 M NaCl was added and stirred for 1 h. Finally, the mixture was dialyzed at room temperature for 72 h and then lyophilized to obtain sodium polyacrylate nanotubes. The corresponding morphology is shown in the figure. Figure 7 As shown.
[0039] Depend on Figure 7 It can be seen that the sodium polyacrylate nanotubes prepared by the above method have smooth surfaces, diameters ranging from 400 to 900 nm, and lengths exceeding the SEM morphology observation range. Example
[0040] A method for preparing sodium polyacrylate nanotubes includes the following steps: 0.4 g of sodium polyacrylate (PAAS) was mixed with 20 mL of water and stirred until homogeneous. Then, 0.01 M NaCl was added and stirred for 1 h. Finally, the mixture was dialyzed at room temperature for 72 h and then lyophilized to obtain sodium polyacrylate nanotubes. The corresponding morphology is shown in the figure. Figure 8 As shown.
[0041] Depend on Figure 8 It can be seen that the sodium polyacrylate nanotubes prepared by the above method have smooth surfaces, diameters ranging from 400 to 900 nm, and lengths exceeding the SEM morphology observation range. Example
[0042] A method for preparing carboxymethyl-β-cyclodextrin nanotubes includes the following steps: 0.4 g of carboxymethyl-β-cyclodextrin (CM-β-CD) was mixed with 20 mL of water and stirred until homogeneous. Then, 0.05 M NaCl was added and stirred for 1 h. Finally, the mixture was dialyzed at room temperature for 72 h and then lyophilized to obtain carboxymethyl-β-cyclodextrin nanotubes. The corresponding morphology is shown in the figure. Figure 8 As shown.
[0043] Depend on Figure 9 It can be seen that the carboxymethyl-β-cyclodextrin nanotubes prepared by the above method have smooth surfaces, diameters ranging from 400 to 800 nm, and lengths exceeding 20 μm. Example
[0044] A method for preparing hydroxypropyl cellulose nanotubes includes the following steps: 0.4 g of hydroxypropyl cellulose (HPC) was mixed with 20 mL of water and stirred until homogeneous. Then, 0.05 M NaCl was added and stirred for 1 h. Finally, the mixture was dialyzed at room temperature for 72 h and then lyophilized to obtain hydroxypropyl cellulose nanotubes. The corresponding morphology is shown in the figure. Figure 10 As shown.
[0045] Depend on Figure 10 It can be seen that the hydroxypropyl cellulose nanotubes prepared by the above method have smooth surfaces, diameters ranging from 500 to 1000 nm, and lengths exceeding the SEM morphology observation range. Example
[0046] This embodiment mainly focuses on the preparation of carbonized chitosan nanotubes and graphitized chitosan nanotubes. The preparation method involves carbonizing the chitosan nanotubes obtained in Example 1 under a protective gas atmosphere to obtain carbonized chitosan nanotubes, and then graphitizing the carbonized chitosan nanotubes under a protective gas atmosphere to obtain graphitized chitosan nanotubes. The specific preparation process is as follows: 0.4 g of chitosan was added to 10 mL of water and stirred until no bubbles appeared. Then, 0.05 M NaCl was added and stirred until well mixed. The mixture was then dialyzed at room temperature for 72 h and freeze-dried to obtain chitosan nanotubes. The chitosan nanotubes were heated from room temperature to 200 °C at a heating rate of 4 °C / min under an argon atmosphere and held for 2 h; then heated from 200 °C to 600 °C at a heating rate of 5 °C / min and held for 2 h to obtain carbonized chitosan nanotubes. The carbonized chitosan nanotubes were treated at 2000 °C for 50–80 s under an argon atmosphere and cooled to obtain graphitized chitosan nanotubes.
[0047] Test case 1. Morphology of nanotubes, etc. Figure 11 Scanning electron microscope (SEM) images of chitosan nanotubes prepared using chitosan as the raw material in Example 11. Figure 11 As shown in (a), the chitosan raw material exhibits an irregular, large-sized sheet-like structure. After molecular self-assembly, as... Figure 11 As shown in (b), the obtained chitosan nanotubes exhibit a slender morphology, with a length exceeding the SEM morphology observation range, and a smooth surface. Figure 11 (d) shows the statistical results of the diameter distribution of chitosan nanotubes, ranging from 150 to 550 nm, with an average diameter of 358 nm.
[0048] 2. Figure 12 The image shows the HRTEM (High Resolution Transmission Electron Microscopy) pattern and the selected area electron diffraction (SAED) pattern of the graphitized chitosan nanotubes prepared in Example 11. Figure 12 (a) is a transmission electron microscope image of the graphitized chitosan nanotubes prepared in Example 11. Figure 12(b) is a high-resolution transmission electron microscope image of graphitized chitosan nanotubes, showing distorted graphite lattice fringes and amorphous carbon regions. Figure 12 (c) is the selected area electron diffraction pattern of graphitized chitosan nanotubes, showing obvious diffraction rings, which represent the (002), (100) and (110) crystal planes of carbon from the inside to the outside.
[0049] 3. Lattice parameters of different materials obtained by X-ray diffraction The X-ray diffraction patterns of the chitosan nanotubes, carbonized chitosan nanotubes, and graphitized chitosan nanotubes prepared in Example 11 are shown below. Figure 13 As shown. By Figure 13 It can be seen that neither chitosan nanotubes nor carbonized chitosan nanotubes have obvious crystallization peaks. Chitosan nanotubes show broad and weak diffraction peaks around 22°, while carbonized chitosan nanotubes show broad and weak diffraction peaks around 26°. Graphitized chitosan nanotubes show very strong and sharp diffraction peaks around 26.5°, which are the (002) crystal plane of carbon. The (100) and (004) crystal planes of carbon appear around 42.2° and 53.9°, respectively, indicating that the graphitized chitosan nanotubes have a high degree of graphitization.
[0050] 4. Raman spectra of samples under graphitization treatment conditions The Raman spectra of the carbonized chitosan nanotubes and graphitized chitosan nanotubes prepared in Example 11 are shown below. Figure 14 As shown. By Figure 14 It can be seen that carbonized chitosan nanotubes are at 1350 cm⁻¹. -1 and 1580 cm -1 Nearby, D and G peaks appeared, and they largely overlapped. In addition to the D and G peaks, graphitized chitosan nanotubes also exhibited a high-intensity 2D peak. The ratio of the areas of the D and G peaks in carbonized chitosan nanotubes is I. D / I G The ratio of the areas of the D peak and the G peak of the graphitized chitosan nanotubes is 1.78. D / I G It is 0.64.
[0051] 5. Atomic force microscopy (AFM) analysis of graphitized nanotubes Atomic force microscopy morphology images of single graphitized chitosan nanotubes and the measured compressive modulus results are shown below. Figure 15 .from Figure 15 (a) It can be concluded that the morphology and diameter of graphitized chitosan nanotubes are related to... Figure 11 The results are consistent with those in the study, indicating that the surface morphology and diameter of the nanotubes did not change after low-temperature carbonization and high-temperature graphitization treatments, and their compressive modulus reached 40-50 GPa.
[0052] 6. Provide detailed diagrams and analysis of fibers obtained through wet spinning. The graphitized carbon nanotubes prepared in Example 11 were used to prepare graphitized nanotube fibers via wet spinning. Specifically, graphitized carbon nanotubes and sodium cholate were mixed in water at a mass ratio of 1:6, with the graphitized nanotubes having a concentration of 0.6 wt% in the mixture. After ultrasonic dispersion at room temperature, the mixture was injected into a coagulation bath through a needle to obtain graphitized nanotube fibers. The coagulation bath consisted of isopropanol and water mixed at a volume ratio of 3:1. After complete coagulation, the graphitized nanotube fibers were immersed in deionized water for 24 hours. After removal, they were dried overnight at room temperature to obtain graphitized chitosan carbon nanotube fibers. The scanning electron microscope (SEM) morphology image is shown below. Figure 16 As shown. By Figure 16 It can be seen that the fiber diameter is about 40μm and the surface is wrinkled.
[0053] Mechanical property analysis was performed on a single graphitized chitosan carbon nanotube fiber. The specific testing procedure is as follows: A single fiber of a certain length was fixed in a universal uniaxial tensile testing machine using a clamp, and the tensile speed was 2 mm / min. The load-strain curve and stress-strain curve of the single fiber were obtained, and the results are as follows. Figure 17 As shown. By Figure 17 It can be seen that the maximum load a single fiber can withstand is 5 cN, the tensile strain is 12%, and the maximum tensile stress is 40 MPa.
[0054] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A graphitized carbon nanotube, characterized in that, The graphitized carbon nanotubes have a graphite lattice stripe structure, a diameter of 400~900nm, a length of centimeters or more, and a graphitization degree of 60~90%.
2. A method for preparing graphitized carbon nanotubes, characterized in that, Includes the following steps: Step 1. Dissolve the natural polymer raw material or polymeric polymer raw material in deionized water, and then add an electrolyte solution to obtain a precursor solution; in the precursor solution, the mass concentration of the natural polymer raw material or polymeric polymer raw material is 1-5 wt%, and the concentration of the electrolyte is 0.01-0.05 mol / L; Step 2. Stir the precursor solution obtained in Step 1, dialyze it, freeze-dry it, and obtain nanotubes; Step 3. The nanotubes obtained in Step 2 are carbonized and graphitized to obtain graphitized carbon nanotubes.
3. The method for preparing graphitized carbon nanotubes according to claim 2, characterized in that, In step 1, the natural polymer raw materials are chitosan, sodium alginate, hydroxypropyl cellulose, hydroxyethyl cellulose, carboxymethyl-β-cyclodextrin, lignin, or sodium carboxymethyl cellulose; the polymer raw materials are polyacrylic acid, sodium polyacrylate, polyglycerol ester, polyvinylidene fluoride-hexafluorophosphate copolymer, or polyvinyl alcohol.
4. The method for preparing graphitized carbon nanotubes according to claim 2, characterized in that, In step 1, the electrolyte is sodium chloride, sodium sulfate, sodium sulfite, silver nitrate, or copper chloride.
5. The method for preparing graphitized carbon nanotubes according to claim 2, characterized in that, In step 1, when the raw material is sodium alginate, sodium carboxymethyl cellulose or sodium polyacrylate, no electrolyte solution is introduced into the precursor solution, and the sodium ion concentration in the precursor solution is controlled at 0.01-0.05 mol / L.
6. The method for preparing graphitized carbon nanotubes according to claim 2, characterized in that, In step 3, the carbonization process is as follows: the nanotubes are placed in a tube furnace and heated to 200-300℃ at a rate of 2-5℃ / min under an inert gas atmosphere, and held for 0.5-3h; then the temperature is increased to 400-600℃ at a rate of 5-10℃ / min and held for 2-6h to complete the carbonization.
7. The method for preparing graphitized carbon nanotubes according to claim 2, characterized in that, In step 3, the graphitization process is as follows: the carbonized nanotubes are placed in a graphitization furnace, and the temperature is adjusted to a range of 1600~2000℃ for 10s by pulse current; the process of "adjusting the temperature range of 1600~2000℃ for 10s by pulse current" is repeated 5~10 times to complete the graphitization.
8. A method for preparing nanotube fibers based on graphitized carbon nanotubes, characterized in that, Graphitized carbon nanotubes are spun into fibers with adjustable length and diameter using a wet spinning method.
9. A method for preparing nanotube fibers based on graphitized carbon nanotubes, characterized in that, Includes the following steps: Step 1. Mix graphitized carbon nanotubes and a surfactant in water, with the concentration of graphitized nanotubes in the mixture being 0.5~1 wt%. Step 2. After sonicating the obtained mixture at room temperature for 60 min, inject it into the coagulation bath through a needle at a rate of 0.1~0.5 cm / min; Step 3. After complete solidification, the graphitized nanotube fibers obtained by wet spinning are immersed in deionized water for 24 hours to remove residual surfactants; then, they are left overnight at ambient temperature to obtain the final graphitized nanotube fibers.
10. The application of graphitized carbon nanotubes prepared by the method of any one of claims 2-7 in electromagnetic absorbing materials, high-performance composite materials or flexible electronic devices.