A method for post-treatment of a chlorosulfonic acid-carbon nanotube dispersion

Abstract

The application provides a post-treatment method of chlorosulfonic acid-carbon nanotube dispersion liquid. The post-treatment method comprises the following steps: providing a chlorosulfonic acid dispersion liquid of carbon nanotubes, wherein a dispersing agent used in the dispersion liquid comprises chlorosulfonic acid; mixing the chlorosulfonic acid dispersion liquid of carbon nanotubes with a first organic solvent to obtain a first dispersion liquid, wherein the first organic solvent is used at least for diluting chlorosulfonic acid and does not react with chlorosulfonic acid; and mixing the first dispersion liquid with a second organic solvent to obtain a second dispersion liquid, wherein the second organic solvent is used at least for reacting with chlorosulfonic acid. The method can realize the removal of chlorosulfonic acid in the organic phase under the condition of ensuring the dispersity of carbon nanotubes, solve the problem that the chlorosulfonic acid-carbon nanotube dispersion system is difficult to be compatible with subsequent processes, and can obtain an undamaged or low-damage carbon nanotube organic dispersion liquid with low energy consumption, high yield and mild conditions.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of carbon nanotube dispersion, and particularly relates to a post-treatment method of chlorosulfonic acid-carbon nanotube dispersion liquid. BACKGROUND

[0002] Carbon nanotubes (carbon tubes, CNT) are one-dimensional nanomaterials with a hollow tubular structure and a high length-diameter ratio. This special nanowire structure enables CNT to have excellent mechanical, electrical, thermal and other properties in the radial direction. One of the important factors affecting the performance of carbon tubes and their composite materials is the length of the carbon tubes. Studies have shown that as the average length of CNT increases, the physical properties of carbon nanotube fibers, thin films and composite materials, such as mechanical strength, are significantly improved, and the thin film conductivity and device mobility are also affected by the length of the carbon nanotubes.

[0003] The CNT raw material obtained by growth is usually dominated by bundles, and inevitably contains impurities such as catalysts and amorphous carbon, which has a great impact on the application of CNT in the fields of optoelectronic devices and composite materials. Therefore, further purification and separation of CNT raw material is needed to obtain carbon nanotubes with higher quality and fewer bundles.

[0004] As a commonly used method for separating CNT, non-covalent method can maintain the integrity of the structure and physicochemical properties of carbon nanotubes to the greatest extent, but the covalent force is weak. In order to overcome the strong van der Waals force between CNT tubes and achieve better dispersion effect, physical methods such as ultrasonic method, ball milling method and shear stress method are needed. However, the mechanical force in these physical methods will cause the length of the dispersed CNT to be significantly shortened compared with the raw material tube, significantly reducing the electrical conductivity of CNT and weakening its mechanical strength. Therefore, many studies using CNT are greatly limited by the inverse relationship between the length and dispersion of CNT, which is one of the important reasons for the large gap between the properties of the obtained CNT materials and the theoretical values.

[0005] To reduce the damage of mechanical action on CNT and ensure that CNT has a certain dispersion, researchers have made various attempts, such as: Wenseleers et al. proposed a slow stirring method to scrape off the loose CNT on the surface to achieve the purpose of dispersing CNT, but this process takes weeks of time, and the yield is extremely low, which is only limited to the preparation of micro samples; Graf et al. reported a high-speed shearing mixing method, which uses transverse friction instead of ultrasonic to replace the weak energy input in the system, and uses longer time to compensate, which successfully disperses CNT in toluene, but this method consumes high energy and takes a long time, and still causes certain damage to CNT; Polina M. et al. use the rapid expansion of supercritical nitrogen embedded in the beam to break up the bundle, and directly inject carbon nanotubes into a surfactant-containing aqueous solution to improve the dispersion of single-walled carbon nanotubes (SWCNT) in aqueous media, but it still needs short-time ultrasonic assisted dispersion, and the dispersion efficiency is low; In addition, Penicaud et al. also reported that Li / Na reduced SWCNT salt can be dissolved in some organic solvents.

[0006] At present, chlorosulfonic acid can disperse carbon nanotubes with low loss or even no loss, and is one of the best solvents for dispersing single-walled carbon nanotubes. The complete reversible protonation process of chlorosulfonic acid enables the carbon tube to overcome the interaction between the tubes and fully disperse in high-purity (>98%) chlorosulfonic acid, so that the carbon nanotubes can be fully dissolved in chlorosulfonic acid without the help of external force, and the carbon nanotubes can be dispersed without damage. However, chlorosulfonic acid is a super acid and reacts violently with water to release heat, which makes it difficult for the chlorosulfonic acid-carbon nanotube dispersion system to be compatible with other normal processes, making subsequent application very difficult, thereby greatly affecting the application of chlorosulfonic acid in dispersing carbon tubes. Andrew R. B et al. loaded the chlorosulfonic acid-carbon nanotube dispersion into a glass syringe, and then extruded the solution into a coagulation bath (acetone, acetonitrile, etc.) through a microsyringe, and then manually pulled and collected the solid product by a motor. This post-processing method of chlorosulfonic acid-carbon nanotube has been widely used in the preparation of macroscopic materials such as carbon nanotube fibers, but the carbon tube samples obtained by this method are mostly micron-sized aggregates with obvious bundling, which cannot maintain the high dispersibility of carbon tubes in chlorosulfonic acid solution. Peng Wang et al. used sodium deoxycholate to directly neutralize the carbon nanotube-chlorosulfonic acid solution, thereby avoiding ultrasonic treatment and ultracentrifugation, to realize the preparation of short-time full-length carbon nanotube aqueous solution, making it possible to realize large-scale and low-cost damage-free aqueous solution processing of high-quality carbon nanomaterials. However, this proton exchange treatment method releases a large amount of heat and is not uniform in the proton exchange reaction, which is easy to cause liquid boiling or splashing, and it is realized in an aqueous solution, which is not compatible with most organic composite systems.

[0007] It can be seen that it is one of the problems to be solved to provide a mild post-treatment method for chlorosulfonic acid-carbon nanotube dispersion system, maintain high aspect ratio of carbon nanotube while ensuring no damage or low damage of carbon nanotube. SUMMARY

[0008] To solve all or part of the above technical problems, the present application provides the following technical solutions:

[0009] One of the purposes of the present application is a post-treatment method of chlorosulfonic acid-carbon nanotube dispersion liquid, the post-treatment method comprising:

[0010] Providing a chlorosulfonic acid dispersion liquid of carbon nanotubes, the dispersant used in the dispersion liquid comprises chlorosulfonic acid;

[0011] Mixing the chlorosulfonic acid dispersion liquid of carbon nanotubes with a first organic solvent to obtain a first dispersion liquid, wherein the first organic solvent is used at least to dilute chlorosulfonic acid and does not react with chlorosulfonic acid;

[0012] Mixing the first dispersion liquid with a second organic solvent to obtain a second dispersion liquid, wherein the second organic solvent is used at least to react with chlorosulfonic acid.

[0013] The post-treatment method provided by the present application is to dilute first and then react, which can make the reaction more mild, increase the spacing between carbon tubes, and enable the entire post-treatment method to be carried out while ensuring the dispersibility of carbon nanotubes, realize the removal of chlorosulfonic acid in the organic phase, and solve the problem that the chlorosulfonic acid-carbon nanotube dispersion system is difficult to be compatible with subsequent processes; and the post-treatment method is efficient and mild, can obtain carbon nanotubes with no damage or low damage, and can maintain the average length of carbon nanotubes, thereby solving the problem of length reduction of carbon tubes caused by the physical dispersion method in the prior art.

[0014] The chlorosulfonic acid dispersion liquid of carbon nanotubes according to the present application refers to a dispersion system in which the dispersant is pure chlorosulfonic acid, or a dispersion system in which the main dispersant is chlorosulfonic acid and other dispersants are also contained.

[0015] The first organic solvent is an organic solvent that does not react with chlorosulfonic acid and has good compatibility with carbon nanotubes. In some embodiments, the first organic solvent comprises dichloromethane, trichloromethane, dichloroethane, or a combination of two or more thereof, but is not limited thereto.

[0016] In some embodiments, the concentration of carbon nanotubes in the chlorosulfonic acid dispersion liquid of carbon nanotubes is 0.01-10 mg / ml.

[0017] In some embodiments, the volume ratio of the chlorosulfonic acid dispersion of carbon nanotubes to the first organic solvent is 1:1 to 1:100. If the volume ratio is too low, a large amount of heat is released during the reaction process, and the distance between the carbon nanotubes is too close, resulting in a large number of bundles and serious agglomeration. If the volume ratio is too high, the concentration of carbon nanotubes in the dispersion is too low, and the post-processing efficiency is too poor.

[0018] The second organic solvent can react with chlorosulfonic acid and does not generate solid substances, and has a certain solubility for carbon nanotubes.

[0019] In some embodiments, the second organic solvent includes one or a combination of more than two of N,N-dimethylacetamide, N,N-dimethylformamide, tetrahydrofuran, dimethyl sulfoxide, acetonitrile, acetone, m-chlorotoluene, and toluene, but is not limited thereto. These solvents can react with chlorosulfonic acid mildly without damaging the carbon nanotubes and without generating hydrogen chloride gas, and the reaction is safer.

[0020] In some embodiments, the second organic solvent is added in an amount such that the pH value of the second dispersion is 6 to 8. The amount of the second organic solvent added is determined by the content of chlorosulfonic acid in the solution. If the solution amount is large, a portion of the supernatant can be taken out after the first dispersion is stable to further reduce the use amount of the second organic solvent. If the second organic solvent is added too little, the dispersion will be too acidic and other complex reactions will easily occur. If the second organic solvent is added too much, the concentration of carbon nanotubes in the dispersion will be too low, causing waste.

[0021] In some embodiments, the volume ratio of the second organic solvent to chlorosulfonic acid is 0.5:1 to 5:1.

[0022] In some embodiments, the post-processing method further includes mixing the second dispersion with a dispersant to obtain a third dispersion. The dispersant is, for example, a carbon nanotube dispersant used in an organic system. In the second dispersion obtained by the present application, chlorosulfonic acid is reacted with the second organic solvent to expose the carbon nanotubes. At this time, other dispersants with good compatibility with subsequent processes can be selected for re-dispersion according to the needs of subsequent processes. The other dispersants are selected according to the specific application of carbon nanotubes and can be any dispersant suitable for dispersing carbon nanotubes in the prior art. The present application does not make special limitations on this, for example, it can be one or more of non-covalent polymers (PCz, PCP, etc.), non-ionic surfactants (TX-100, etc.) dissolved in organic solvents, and high-viscosity solvents (m-cresol, PVP, etc.) with good carbon nanotube dispersibility.

[0023] Of course, in some embodiments, the obtained second dispersion liquid can be directly used in subsequent processes, such as mixing and forming an organic polymer (PMMA, resin, etc.) with the carbon nanotubes to prepare a composite film, fiber or bulk composite material, etc.

[0024] In some embodiments, during the mixing of the second dispersion liquid with the dispersant, one or more of ultrasonic, homogenization, stirring, and shearing are used to assist in the dispersion. For example, short-time ultrasonic assistance can be used, with an ultrasonic time of 5 s to 20 min. The carbon nanotubes treated by the post-processing method of the present application maintain good dispersibility, and when they need to be dispersed in other dispersants based on subsequent processes, they can be quickly and well dispersed in the other dispersants. At this time, physical methods such as ultrasonic can be used to assist in the dispersion, but only short-time assistance is needed to achieve good dispersion, avoiding the loss of carbon nanotubes due to long-time ultrasonic treatment.

[0025] In some embodiments, the carbon nanotubes include one or a combination of single-walled carbon nanotubes (such as semiconducting tubes, single-chiral tubes, etc.), double-walled carbon nanotubes, and multi-walled carbon nanotubes. In some embodiments, the carbon nanotubes are raw material tubes and / or carbon nanotubes obtained after separation. That is, the post-processing method provided by the present application is generally applicable to various forms of carbon nanotube materials or composite materials based on carbon nanotubes.

[0026] In some embodiments, the method for preparing the chlorosulfonic acid dispersion liquid of the carbon nanotubes includes one or a combination of standing, ultrasonic, stirring, and centrifugation. The present application does not make any special limitation on the method for obtaining the chlorosulfonic acid dispersion liquid of the carbon nanotubes, and any method in the prior art can be used to obtain the chlorosulfonic acid dispersion liquid of the carbon nanotubes. For example, in a nitrogen environment or a well-ventilated kitchen with low humidity, an appropriate amount of chlorosulfonic acid (purity greater than or equal to 97%, carbon nanotube / chlorosulfonic acid concentration of 0.01-2 mg / ml) is added to the carbon nanotubes, and stirring is performed until the carbon nanotubes are fully dispersed.

[0027] In some embodiments, before preparing the chlorosulfonic acid dispersion liquid of the carbon nanotubes, the carbon nanotube raw material used is subjected to catalyst removal and amorphous carbon removal operations. The removal of catalysts and amorphous carbon can use any method for pretreating carbon nanotube raw materials in the prior art, such as the method disclosed in Superacid-Surfactant Exchange: Enabling Nondestructive Dispersion of Full-Length Carbon Nanotubes in Water (ACS Nano. 2017 Sep 26; 11(9): 9231-9238.), and the present application does not make any special limitation.

[0028] Compared with the prior art, the present application has at least the following beneficial effects:

[0029] The post-treatment method provided by the present application can realize the removal of chlorosulfonic acid in the organic phase while ensuring good dispersibility of the carbon nanotubes, solve the problem that the chlorosulfonic acid-carbon nanotube dispersion system is difficult to be compatible with subsequent processes, and obtain undamaged or low-damage carbon nanotubes, so that the carbon nanotubes can maintain good average length and solve the problem of length reduction of carbon nanotubes caused by the physical dispersion method in the prior art.

[0030] The method has wide applicability, can select different types of carbon nanotubes, and can select different solvents and dispersants according to the requirements of subsequent processes, and the obtained carbon nanotube dispersion liquid can be further applied to carbon nanotube separation and preparation of carbon nanotube composite materials.

[0031] The method is simple to operate, common in instrument equipment, controllable in the amount of reagents used in the reaction, and can be used for large-scale preparation of carbon nanotube dispersion liquid at low cost. BRIEF DESCRIPTION OF DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments described in the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0033] Figure 1 is a flowchart of the post-treatment method of the chlorosulfonic acid-carbon nanotube dispersion liquid in Example 1 of the present application.

[0034] Figure 2 is the ultraviolet absorption spectrum of the second dispersion liquid obtained in Example 1 of the present application after adding a dispersant.

[0035] Figure 3 is the SEM image of the second dispersion liquid prepared into a thin film in Example 1 of the present application;

[0036] Figure 4 is the Raman spectrum of the second dispersion liquid prepared into a thin film in Example 1 of the present application;

[0037] Figure 5 is a real object image of the third dispersion liquid in Example 1 of the present application;

[0038] Figure 6 is a comparison chart of the length of carbon nanotubes in the dispersion liquid obtained in Example 1 and Comparative Example 1 of the present application. DETAILED DESCRIPTION

[0039] The technical solutions of the present application are described in detail below with reference to specific embodiments, so that those skilled in the art can better understand and implement the technical solutions of the present application. The specific functional details disclosed herein should not be interpreted as limiting, but only as a basis for the claims and for teaching those skilled in the art to employ the representative basis of the present application in different ways in any appropriate detailed embodiment.

[0040] The carbon nanotubes used in the present application are purchased from Nanointegris Company. Unless otherwise specified, other raw materials and reagents used in the present application are commercially available.

[0041] Example 1

[0042] This embodiment provides a post-treatment method for a chlorosulfonic acid-carbon nanotube dispersion liquid, as shown in the following: Figure 1

[0043] A certain amount of carbon nanotubes is weighed, and chlorosulfonic acid (purity greater than or equal to 97%) is added to the carbon nanotubes in a nitrogen environment with low humidity in a well-ventilated kitchen. The carbon nanotubes are fully dispersed by stirring to obtain a chlorosulfonic acid dispersion liquid of carbon nanotubes, wherein the concentration of carbon nanotubes is 0.1 mg / ml.

[0044] The chlorosulfonic acid dispersion liquid of carbon nanotubes is added to dichloromethane, and the volume ratio of the chlorosulfonic acid dispersion liquid of carbon nanotubes to dichloromethane is 1 / 50 to obtain a first dispersion liquid.

[0045] N,N-dimethylacetamide is added to the first dispersion liquid until the pH value of the dispersion liquid is adjusted to 7 to obtain a second dispersion liquid.

[0046] As shown in the following: Figure 1 The second dispersion liquid prepared can be well compatible with other processes, and according to actual needs, the second dispersion liquid can be directly used for subsequent processes, such as compounding with other organic polymers to prepare a carbon nanotube composite material. Alternatively, according to the process characteristics required for subsequent processes, a suitable dispersant is selected to disperse the carbon nanotubes in the second dispersion liquid again, and then the subsequent processes such as composite material preparation are performed.

[0047] Figure 2 is the absorption spectrum of the carbon nanotube dispersion liquid obtained by using the post-treatment method of the present embodiment, Figure 3 is the SEM image of the carbon nanotube film deposited by using the solution deposition method on the carbon nanotubes of the present embodiment, and according to Figure 2 and Figure 3 It can be known that the carbon nanotube dispersion liquid thus obtained has good dispersibility.

[0048] Figure 4 ​It is a Raman spectrum of the carbon nanotube film obtained by using the solution drop coating method on the carbon nanotube of the embodiment, which is a typical single-walled carbon nanotube Raman spectrum, the ratio of D peak to G peak is close to the ratio of the used carbon nanotube raw material, indicating that the post-processing method provided by the application does not damage the carbon nanotube.

[0049] Figure 5 It is a physical picture of the carbon nanotube dispersion liquid obtained by the embodiment after standing for 5 days, and the carbon nanotube dispersion liquid obtained by the method has good dispersion stability.

[0050] Embodiment 2

[0051] The carbon nanotube raw material is pretreated, specifically: the carbon nanotube raw material is soaked and stirred in concentrated hydrochloric acid for 3h, the catalyst in the nanotube raw material is removed, and then annealed at a temperature of 300℃ for 30min to remove the amorphous carbon in the raw material;

[0052] The pretreated carbon nanotube is weighed, and chlorosulfonic acid (purity greater than or equal to 97%) is added to the carbon nanotube in a nitrogen environment and a low-humidity ventilation kitchen, and the carbon nanotube is fully dispersed by stirring to obtain a chlorosulfonic acid dispersion liquid of the carbon nanotube, wherein the concentration of the carbon nanotube is 0.01mg / ml;

[0053] Dichloromethane is added to the chlorosulfonic acid dispersion liquid of the carbon nanotube, and the volume ratio of the chlorosulfonic acid dispersion liquid of the carbon nanotube to dichloromethane is 1:1 to obtain a first dispersion liquid.

[0054] N,N-dimethylacetamide is added to the first dispersion liquid until the pH value of the dispersion liquid is reacted to 6 to obtain a second dispersion liquid.

[0055] Triton is added to the above-mentioned second dispersion liquid, and short-time ultrasonic dispersion is assisted for about 3min to obtain a third dispersion liquid. The obtained third dispersion liquid is mixed with an organic polymer PMMA to form a carbon nanotube composite material.

[0056] Embodiment 3

[0057] A certain mass of carbon nanotube is weighed, and chlorosulfonic acid (purity greater than or equal to 97%) is added to the carbon nanotube in a nitrogen environment and a low-humidity ventilation kitchen, and the carbon nanotube is fully dispersed by stirring to obtain a chlorosulfonic acid dispersion liquid of the carbon nanotube, wherein the concentration of the carbon nanotube is 2mg / ml;

[0058] Trichloromethane is added to the chlorosulfonic acid dispersion liquid of the carbon nanotube, and the volume ratio of the chlorosulfonic acid dispersion liquid of the carbon nanotube to trichloromethane is 1:100 to obtain a first dispersion liquid.

[0059] Tetrahydrofuran is added to the first dispersion liquid until the pH value of the dispersion liquid is reacted to 8 to obtain a second dispersion liquid.

[0060] Example 4

[0061] A certain amount of carbon nanotubes was weighed, and chlorosulfonic acid (purity greater than or equal to 97%) was added to the carbon nanotubes in a ventilated kitchen with a low humidity and a nitrogen environment, and the carbon nanotubes were fully dispersed by stirring to obtain a chlorosulfonic acid dispersion of the carbon nanotubes, wherein the concentration of the carbon nanotubes was 10 mg / ml;

[0062] Chloroform was added to the chlorosulfonic acid dispersion of the carbon nanotubes, and the volume ratio of the chlorosulfonic acid dispersion of the carbon nanotubes to chloroform was 1:50 to obtain a first dispersion;

[0063] N,N-dimethylacetamide was added to the first dispersion until the pH value of the dispersion reacted to 7 to obtain a second dispersion.

[0064] Example 5

[0065] A certain amount of carbon nanotubes was weighed, and chlorosulfonic acid (purity greater than or equal to 97%) was added to the carbon nanotubes in a ventilated kitchen with a low humidity and a nitrogen environment, and the carbon nanotubes were fully dispersed by stirring to obtain a chlorosulfonic acid dispersion of the carbon nanotubes, wherein the concentration of the carbon nanotubes was 1 mg / ml;

[0066] Chloroform was added to the chlorosulfonic acid dispersion of the carbon nanotubes, and the volume ratio of the chlorosulfonic acid dispersion of the carbon nanotubes to chloroform was 1:50 to obtain a first dispersion;

[0067] N,N-dimethylacetamide was added to the first dispersion until the pH value of the dispersion reacted to 6 to obtain a second dispersion.

[0068] Example 6

[0069] A certain amount of carbon nanotubes was weighed, and chlorosulfonic acid (purity greater than or equal to 97%) was added to the carbon nanotubes in a ventilated kitchen with a low humidity and a nitrogen environment, and the carbon nanotubes were fully dispersed by stirring to obtain a chlorosulfonic acid dispersion of the carbon nanotubes, wherein the concentration of the carbon nanotubes was 1 mg / ml;

[0070] Chloroform was added to the chlorosulfonic acid dispersion of the carbon nanotubes, and the volume ratio of the chlorosulfonic acid dispersion of the carbon nanotubes to chloroform was 1:50 to obtain a first dispersion;

[0071] N,N-dimethylacetamide was added to the first dispersion until the pH value of the dispersion reacted to 7 to obtain a second dispersion.

[0072] Comparative Example 1

[0073] The carbon nanotubes are dispersed by using a common ultrasonic treatment method, the dispersant is PCz, the concentration of the carbon nanotubes in the dispersion liquid is 1 mg / ml, the ultrasonic power is 40%, and the time is 30 min

[0074] Figure 6 is a length statistical diagram of the carbon nanotubes obtained by using the post-treatment method of the embodiment 1 of the present application and the ultrasonic treatment method of the comparative example, from Figure 6 It can be known that the carbon nanotubes obtained by the embodiment 1 of the present application have a greater average length, about 0.92 microns, while the average length of the carbon nanotubes obtained by the ultrasonic treatment of the comparative example 1 is 0.65 microns.

[0075] Comparative example 2

[0076] The difference between the comparative example 2 and the embodiment 1 is only that the first organic solvent is not used for dilution, and the second organic solvent is directly used for reaction, it is found that the reaction is violent and the solvent splashing phenomenon appears, and the dispersibility and dispersion stability of the carbon nanotubes in the dispersion liquid are significantly reduced.

[0077] Comparative example 3

[0078] The difference between the comparative example 3 and the embodiment 1 is only that the second organic solvent is not used for reaction, and a large amount of chlorosulfonic acid exists in the dispersion liquid, which is extremely easy to react with the dispersant, the carbon nanotubes and the composite material, and cannot form effective dispersion, and it is difficult to carry out subsequent application.

[0079] In summary, the reaction and removal of chlorosulfonic acid in the organic phase are realized by the dilution-reaction two-step method, the process is efficient and mild, the reaction process is more mild by dilution, and the danger is lower. The method can realize the preparation of the carbon nanotube dispersion liquid with more complete average length reservation under the condition of ensuring the dispersibility. The method can be combined with various organic-carbon nanotube composite systems by adjusting the types of organic solvents and dispersants.

[0080] Aspects, embodiments, features, and examples of the present application should be considered illustrative in all aspects and are not intended to limit the present application, and the scope of the present application is only defined 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 application.

[0081] In addition, the present inventors have also carried out tests with other raw materials, process operations and process conditions described in the present specification with reference to the foregoing embodiments, and all ideal results have been obtained.

[0082] While the application has been described with reference to the illustrative embodiments, those skilled in the art will understand that various other changes, omissions, and / or additions can be made without departing from the spirit and scope of the application. Further, many modifications can be made to adapt a particular situation or material to the teachings of the application without departing from its scope. Therefore, it is intended that the application not be limited to the disclosed embodiments, but will include all embodiments falling within the scope of the appended claims. Moreover, unless specifically stated otherwise, any use of the terms first, second, etc., does not denote any ordinal, or importance, but merely distinguishes one element from another.

Claims

1. A method for post-treatment of a chlorosulfonic acid-carbon nanotube dispersion, characterized by, The application relates to a method for preparing a carbon nanotube dispersion liquid, which comprises the following steps: providing a chlorosulfonic acid dispersion liquid of carbon nanotubes, wherein a dispersing agent used in the dispersion liquid comprises chlorosulfonic acid; mixing the chlorosulfonic acid dispersion liquid of carbon nanotubes with a first organic solvent in a volume ratio of 1:1-1:100 to obtain a first dispersion liquid, wherein the first organic solvent is used at least for diluting chlorosulfonic acid and does not react with chlorosulfonic acid; mixing the first dispersion liquid with a second organic solvent to obtain a second dispersion liquid, wherein the second organic solvent is selected from one or more than two combinations of N,N-dimethylacetamide, N,N-dimethylformamide, tetrahydrofuran, dimethyl sulfoxide, acetonitrile, acetone, m-chlorotoluene and toluene, and the volume ratio of the second organic solvent to chlorosulfonic acid is 0.5:1-5:

1. The first organic solvent comprises one or more than two combinations of dichloromethane, trichloromethane, dichloroethane and trichloroethane. The concentration of the carbon nanotubes in the chlorosulfonic acid dispersion liquid of carbon nanotubes is 0.01-10 mg / ml. The second organic solvent is added in an amount such that the pH value of the second dispersion liquid is 6-8.

2. The post-processing method of claim 1, wherein: The application further relates to a method for preparing a carbon nanotube dispersion liquid, which comprises the following steps: providing a chlorosulfonic acid dispersion liquid of carbon nanotubes, wherein a dispersing agent used in the dispersion liquid comprises chlorosulfonic acid; mixing the chlorosulfonic acid dispersion liquid of carbon nanotubes with a first organic solvent in a volume ratio of 1:1-1:100 to obtain a first dispersion liquid, wherein the first organic solvent is used at least for diluting chlorosulfonic acid and does not react with chlorosulfonic acid; mixing the first dispersion liquid with a second organic solvent to obtain a second dispersion liquid, wherein the second organic solvent is selected from one or more than two combinations of N,N-dimethylacetamide, N,N-dimethylformamide, tetrahydrofuran, dimethyl sulfoxide, acetonitrile, acetone, m-chlorotoluene and toluene, and the volume ratio of the second organic solvent to chlorosulfonic acid is 0.5:1-5:

1.

3. The post-processing method of claim 1, wherein: The first organic solvent comprises one or more than two combinations of dichloromethane, trichloromethane, dichloroethane and trichloroethane.

4. The post-processing method of claim 1, wherein: The concentration of the carbon nanotubes in the chlorosulfonic acid dispersion liquid of carbon nanotubes is 0.01-10 mg / ml.

5. The post-processing method of claim 1, wherein, The second organic solvent is added in an amount such that the pH value of the second dispersion liquid is 6-8. The application further relates to a method for preparing a carbon nanotube dispersion liquid, which comprises the following steps: providing a chlorosulfonic acid dispersion liquid of carbon nanotubes, wherein a dispersing agent used in the dispersion liquid comprises chlorosulfonic acid; mixing the chlorosulfonic acid dispersion liquid of carbon nanotubes with a first organic solvent in a volume ratio of 1:1-1:100 to obtain a first dispersion liquid, wherein the first organic solvent is used at least for diluting chlorosulfonic acid and does not react with chlorosulfonic acid; mixing the first dispersion liquid with a second organic solvent to obtain a second dispersion liquid, wherein the second organic solvent is selected from one or more than two combinations of N,N-dimethylacetamide, N,N-dimethylformamide, tetrahydrofuran, dimethyl sulfoxide, acetonitrile, acetone, m-chlorotoluene and toluene, and the volume ratio of the second organic solvent to chlorosulfonic acid is 0.5:1-5:

1.

6. The post-processing method of claim 1, wherein: The first organic solvent comprises one or more than two combinations of dichloromethane, trichloromethane, dichloroethane and trichloroethane.

7. The post-processing method of claim 1, wherein: The concentration of the carbon nanotubes in the chlorosulfonic acid dispersion liquid of carbon nanotubes is 0.01-10 mg / ml.

8. The post-processing method of claim 1, wherein: The second organic solvent is added in an amount such that the pH value of the second dispersion liquid is 6-8.

9. The post-processing method of claim 5, wherein: ​

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