High-dispersity carbon nanotube suspension and preparation method thereof

Abstract

The invention discloses a preparation method of a high-dispersity carbon nanotube suspension, which comprises the following steps: S1, carrying out free radical copolymerization reaction and quaternization reaction on three raw materials of dimethylamino acrylate, furyl olefin and butadiene to obtain a quaternary ammonium salt cationic polymer chain segment; s2, carrying out free radical copolymerization reaction on the three raw materials, and then carrying out Diels-Alder reaction to obtain a sulfonate anion polymer chain segment; s3, carrying out ion pairing on the anion-cation polymer chain segment to obtain an ion pair polymer; and S4, compounding the high-dispersity carbon nanotube suspension liquid with a carbon nanotube, organic thixotropic wax and a polar organic solvent to obtain the high-dispersity carbon nanotube suspension liquid. According to the preparation method disclosed by the invention, high-concentration uniform dispersion of the carbon nanotubes is realized, the storage stability and thixotropic adjustability are also remarkably improved, the carbon nanotubes almost have no sedimentation after standing and can be quickly re-dispersed, and the strict requirements of rubber composite materials and the like on long-term stability and machinability can be met.

Description

Technical Field

[0001] This invention relates to the technical field of carbon nanotubes, and more particularly to a highly dispersible carbon nanotube suspension and its preparation method. Background Art

[0002] Carbon nanotubes (CNTs) are considered ideal reinforcing and functional fillers in rubber, coatings, and electromagnetic shielding due to their excellent mechanical, electrical, and thermal properties. However, due to their extremely high specific surface area and strong van der Waals forces, CNTs are prone to aggregation, entanglement, and sedimentation in solvents or polymer matrices, resulting in limited dispersion concentration, poor storage stability, and a narrow processing window. Existing technologies often employ small-molecule surfactants and covalent or non-covalent modifiers to surface-treat CNTs to improve their dispersibility, but these methods generally suffer from the following drawbacks: small-molecule dispersants are prone to migration and have poor thermal stability, easily failing under high temperature or high shear conditions; while covalent modification can improve bonding strength, it disrupts the intrinsic structure of CNTs, leading to a decrease in electrical and thermal conductivity; and while non-covalent modification preserves structural integrity, weak interfacial bonding makes re-aggregation likely during long-term storage or cyclic processing. Furthermore, traditional suspensions exhibit poor compatibility with polar / non-polar matrices during rubber compounding, resulting in significant interfacial stress concentration and making it difficult to balance mechanical reinforcement and processing performance. Therefore, there is an urgent need for a novel suspension technology that can achieve high-concentration stable dispersion, long-term storage resistance to sedimentation, good compatibility with rubber matrix, and easy redispersibility while maintaining the intrinsic properties of carbon nanotubes. Summary of the Invention

[0003] In view of the shortcomings of the prior art, the present invention provides a method for preparing a highly dispersible carbon nanotube suspension to solve the technical problems existing in traditional carbon nanotube dispersion technology, such as low dispersion concentration, poor stability, easy agglomeration and sedimentation, weak interfacial bonding with rubber matrix, and difficulty in redispersion.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] A method for preparing a highly dispersed carbon nanotube suspension, the method comprising the following steps:

[0006] S1: Dimethylaminoacrylate, furanyl olefin, and butadiene are mixed in a first ratio and subjected to free radical copolymerization in the presence of a free radical initiator. After the reaction is completed, methyl bromide is added to the system to carry out a quaternization reaction to obtain quaternary ammonium salt cationic polymer segments. In step S1, dimethylaminoacrylate, furanyl olefin, and butadiene are constructed into a flexible main chain through free radical copolymerization, and then the tertiary amines on the side chains are quaternized with methyl bromide to generate high-density, regularly distributed quaternary ammonium salt cationic groups. This segment has the characteristics of high cationic density, controllable molecular weight, and the ability of the terminal furan to continue to participate in the Diels-Alder reaction. It can subsequently form strong electrostatic-ion pair interactions with sulfonate anionic segments, providing efficient surface anchoring sites for carbon nanotubes. At the same time, it endows the system with good polar compatibility and redispersibility, fundamentally solving the problems of easy migration, poor thermal stability, and insufficient compatibility with rubber matrix of traditional small molecule cationic modifiers.

[0007] S2: Dimethylaminoacrylate, furanyl olefin, and butadiene are mixed in a second ratio and subjected to free radical copolymerization in the presence of a free radical initiator. Subsequently, sodium benzenesulfonate maleimide is added to the reaction system to carry out a Diels-Alder reaction, yielding sulfonate anionic polymer segments. In step S2, sodium benzenesulfonate maleimide is introduced after free radical copolymerization to carry out a Diels-Alder reaction, allowing sulfonate groups to be covalently bonded to the polymer side chains at high density, forming well-defined and uniformly distributed sulfonate anionic segments. These segments not only form ion pairs with quaternary ammonium salt segments in equimolar matching but also retain the active furan / maleimide structure, which can undergo secondary crosslinking with rubber molecular chains in subsequent processing, improving interfacial strength. This solves the problems of easy precipitation, uneven dispersion, and weak interfacial bonding with the matrix in traditional physical coating of sulfonates, and provides a quantitative stoichiometric basis for the precise construction of subsequent ion-pair polymers.

[0008] S3: The quaternary ammonium salt cationic polymer segments obtained in step S1 and the sulfonate polymer anionic segments obtained in step S2 are dispersed in a mixed solvent at an equimolar ratio and heated and stirred for 2-6 hours to achieve sufficient ion pairing. After separation, the by-product salt impurities are removed, and the pure ion-pair polymer is obtained after vacuum drying. In step S3, the equimolar quaternary ammonium salt cationic segments and sulfonate anionic segments are heated and stirred in a mixed solvent to form a macromolecular coupling agent with a "polyelectrolyte composite" structure through electrostatic-ion pair self-assembly. This step achieves complete neutralization of positive and negative charges, eliminates the shielding effect of free small molecule salts on the surface of carbon nanotubes, and obtains functionalized macromolecules with high molecular weight, good thermal stability, and self-dispersibility in polar solvents. This fundamentally avoids the problems of decreased conductivity, deterioration of thermal aging performance, and interference with rubber vulcanization systems caused by the residual free ions in traditional ionic dispersants.

[0009] S4: Carbon nanotubes, the ion-pair polymer obtained in step 3, organic thixotropic wax, and polar organic solvent are compounded in a certain proportion and fully dispersed to obtain the highly dispersed carbon nanotube suspension. In step S4, after compounding carbon nanotubes, ion-pair polymer, organic thixotropic wax, and polar solvent, the ion-pair polymer forms a dense and reversible "polymer coating layer" on the surface of carbon nanotubes through electrostatic-π-π multiple interactions, and the thixotropic wax constructs a three-dimensional thixotropic network. This system achieves stable dispersion of carbon nanotubes in solvents at high concentrations (≥7wt%) and low viscosity (<2000mPa·s, 25℃), while also possessing advantages such as adjustable thixotropy, rapid redispersibility (<30s), and performance degradation of <5% after 50 cycles of thermal cycling (-40~85℃). It solves the problems of easy sedimentation, irreversible high shear damage, and poor compatibility with rubber mixing processes in traditional suspensions, providing key raw materials and technical support for the mass production of high-performance carbon nanotube modified rubber composites and seals.

[0010] As a preferred technical solution, the dimethylaminoacrylate is at least one of 3-(dimethylamino)propyl acrylate, 3-dimethylaminoneopentyl acrylate, 3-(dimethylamino)propyl methacrylate, and 2-dimethylaminoethyl methacrylate.

[0011] As a preferred technical solution, the furanyl olefin is at least one of 2-vinyl-5-methyl-furan, 2-vinylfuran, allyl 2-furancarboxylate, and 3-(2-furanyl)propyl acrylate.

[0012] As a preferred technical solution, in step S1, the molar ratio of dimethylaminoacrylate, furanyl olefin and butadiene is 1-3:1:2-5.

[0013] As a preferred technical solution, the preparation method of the sodium benzenesulfonate maleimide is as follows: furan and maleic anhydride in a molar ratio of 1:1 are dissolved in excess 1,4-dioxane. After the reaction, the product is dissolved in methanol with sodium p-aminobenzenesulfonate under ice bath conditions. The mixture is heated to 60-80°C and stirred to react. Then, the product is added to toluene and refluxed at 120-150°C. After separation, the sodium benzenesulfonate maleimide is obtained.

[0014] As a preferred technical solution, in step S2, the molar ratio of dimethylaminoacrylate, furanyl olefin and butadiene is 1:1 to 3:2 to 5.

[0015] As a preferred technical solution, the molar amount of furanyl olefin in step S2 is equal to the molar amount of dimethylamino acrylate in step 1.

[0016] As a preferred technical solution, the organic thixotropic wax is at least one of hydrogenated castor oil, polyamide wax, or dextrin fatty acid ester.

[0017] As a preferred technical solution, the polar organic solvent is at least one of N-methylpyrrolidone, dimethyl sulfoxide, or N,N-dimethylformamide.

[0018] Another aspect of the present invention is to provide a highly dispersible carbon nanotube suspension, which is prepared by the method described above for preparing a highly dispersible carbon nanotube suspension.

[0019] The beneficial effects of this invention are:

[0020] This invention discloses a method for preparing a highly dispersible carbon nanotube suspension. By constructing ion pairs between quaternary ammonium salt cationic polymer segments and sulfonate anionic polymer segments in an equimolar ratio, a macromolecular coupling agent is formed, significantly improving the dispersion stability and redispersibility of carbon nanotubes in polar solvents. Simultaneously, an organic thixotropic wax synergistically constructs a three-dimensional network with the ion-pair polymer, inhibiting sedimentation and aggregation of carbon nanotubes during storage. This method not only achieves simultaneous surface functionalization and dispersion of carbon nanotubes but also ensures that the suspension maintains a viscosity and conductivity change rate of <5% under high shear and repeated thermal cycling (-40℃ to 85℃, 50 cycles). This design not only enhances the interfacial bonding strength between carbon nanotubes and the rubber matrix but also preserves the intrinsic electrical, thermal, and mechanical reinforcing properties of carbon nanotubes, facilitating their efficient application in rubber composites, seals, and electromagnetic shielding coatings.

[0021] In summary, the highly dispersible carbon nanotube suspension of this invention not only possesses excellent storage stability (sedimentation rate <1% after 60 days of standing, redispersibility <30s) and thixotropic adjustability, but also exhibits high conductivity retention (≥90%, 25℃, 60 days) and good processing compatibility. Its comprehensive performance can meet the long-term stability and consistency requirements of carbon nanotube dispersion systems in different processes, providing key raw materials and technical support for the mass production of high-performance carbon nanotube-modified rubber composites and seals. Detailed Implementation

[0022] The following description is intended to disclose the invention and enable those skilled in the art to implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art.

[0023] Example 1

[0024] The method for preparing the highly dispersed carbon nanotube suspension in this embodiment includes the following steps:

[0025] S1: 0.10 mol of 3-(dimethylamino)propyl acrylate, 0.05 mol of 2-vinyl-5-methylfuran, and 0.20 mol of butadiene were added to a 250 mL three-necked flask equipped with a reflux condenser, a nitrogen inlet, and a mechanical stirrer. 80 mL of dry 1,4-dioxane was added, and nitrogen was purged for 30 min to remove oxygen. The mixture was then heated to 70 °C and 0.15 g of azobisisobutyronitrile (AIBN) was injected in one go. The mixture was stirred at 400 rpm for 4 h under nitrogen protection to complete the free radical copolymerization. After the reaction was completed, the system was cooled to room temperature, and 0.12 mol of bromomethane (dissolved in 20 mL of anhydrous ethanol) was slowly added dropwise. The temperature was maintained at 25 °C, and the reaction was continued for 2 h to complete the quaternization. The solvent and residual bromomethane were then removed by vacuum distillation. The mixture was precipitated with diethyl ether and dried under vacuum to obtain the quaternary ammonium salt cationic polymer segments.

[0026] S2: 3-(dimethylamino)propyl acrylate (0.1 mol), 2-vinyl-5-methylfuran (0.1 mol), and butadiene (0.3 mol) were subjected to free radical copolymerization at 70 °C and 0.12 g AIBN for 4 h under the same operation. Then, sodium benzenesulfonate maleimide (0.05 mol, prepared in advance according to the method described in the specification) was added to the reaction system in one go. The temperature was raised to 80 °C and stirred for 6 h to complete the Diels-Alder reaction. After the reaction was completed, the solvent was removed under reduced pressure. Salt impurities were removed by recrystallization twice with methanol-water (volume ratio 1:1). The sulfonate anionic polymer segments were obtained by vacuum drying.

[0027] S3: The above-mentioned quaternary ammonium salt cationic polymer segments and sulfonate anionic polymer segments were accurately weighed in an equimolar ratio (based on the molar charge of the quaternary ammonium salt and sulfonate) and added together to a mixed solvent of N,N-dimethylformamide / ethanol (volume ratio 3:1) (mass percentage of solute 35%, total mass 100g). The mixture was stirred at 80℃ for 3h to complete ion pairing. Then, acetone was added dropwise for recrystallization and the mixture was filtered. The mixture was washed three times with acetone and dried under vacuum at 60℃ for 12h to obtain a pure ion-paired polymer.

[0028] S4: Add 3.2 g of multi-walled carbon nanotubes (outer diameter 10-20 nm, length 5-15 μm, ash content <1%) to 35 mL of N-methylpyrrolidone and pre-ultrasound for 30 min. Then add the above-mentioned ion-pair polymer (4.0 g) and hydrogenated castor oil (0.4 g), ultrasonically disperse for 45 min and mechanically stir at 600 rpm to obtain a uniform and highly dispersed carbon nanotube suspension.

[0029] The preparation method of sodium benzenesulfonate maleimide is as follows: furan and maleic anhydride in a molar ratio of 1:1 are dissolved in excess 1,4-dioxane. After the reaction, the product is dissolved in methanol with sodium p-aminobenzenesulfonate (molar ratio of 1:1.05) under ice bath conditions. After stirring the reaction at 60-80°C, the product is added to toluene and refluxed at 120-150°C. After separation, the sodium benzenesulfonate maleimide is obtained.

[0030] Example 2

[0031] The method for preparing the highly dispersed carbon nanotube suspension in this embodiment includes the following steps:

[0032] S1: 0.12 mol of 2-dimethylaminoethyl methacrylate, 0.06 mol of 3-(2-furanyl)propyl acrylate, and 0.18 mol of butadiene were added to a 250 mL three-necked flask equipped with a reflux condenser, a nitrogen inlet, and a mechanical stirrer. 90 mL of dry dimethyl sulfoxide was added, and nitrogen was purged for 30 min to remove oxygen. The mixture was then heated to 75 °C and 0.18 g of azobisisobutyronitrile (AIBN) was injected in one go. The mixture was stirred at 450 rpm for 5 h under nitrogen protection to complete the free radical copolymerization. After the reaction was completed, the system was cooled to room temperature, and 0.14 mol of bromomethane (dissolved in 20 mL of anhydrous ethanol) was slowly added dropwise. The temperature was maintained at 30 °C and the reaction was continued for 2.5 h to complete the quaternization. Subsequently, the solvent and residual bromomethane were removed by vacuum distillation, and the mixture was precipitated with acetone and dried under vacuum to obtain the quaternary ammonium salt cationic polymer segments.

[0033] S2: 2-Dimethylaminoethyl methacrylate (0.12 mol), 3-(2-furanyl)propyl acrylate (0.12 mol), and butadiene (0.24 mol) were subjected to free radical copolymerization at 75 °C and 0.15 g AIBN for 5 h under the same operation. Sodium benzenesulfonate maleimide (same as in Example 1, 0.06 mol) was then added to the reaction system in one go. The temperature was raised to 85 °C and stirred for 7 h to complete the Diels-Alder reaction. After the reaction was completed, the solvent was removed under reduced pressure, and the salt impurities were removed by recrystallization twice with ethanol-water (volume ratio 1:2). The sulfonate anionic polymer segments were obtained by vacuum drying.

[0034] S3: The above-mentioned quaternary ammonium salt cationic polymer segments and sulfonate anionic polymer segments were accurately weighed in an equimolar ratio (based on the molar charge of the quaternary ammonium salt and sulfonate) and added together to a mixed solvent of dimethyl sulfoxide / isopropanol (volume ratio 2:1) (mass percentage of solute 35%, total mass 100g). The mixture was stirred at 85°C for 4 hours to complete ion pairing. Then, ethanol was added dropwise for recrystallization and the mixture was filtered. The mixture was washed three times with ethanol and dried under vacuum at 70°C for 14 hours to obtain a pure ion-paired polymer.

[0035] S4: Add multi-walled carbon nanotubes (3.6g, same as in Example 1) to 35mL of N,N-dimethylformamide and sonicate for 35min. Then add the above-mentioned ion-pair polymer (4.4g) and polyamide wax (0.45g), sonicate for 50min and mechanically stir at 650rpm to obtain a uniform and highly dispersed carbon nanotube suspension.

[0036] Example 3

[0037] The method for preparing the highly dispersed carbon nanotube suspension in this embodiment includes the following steps:

[0038] S1: 0.11 mol of 3-dimethylaminoneopentyl acrylate, 0.055 mol of 2-vinylfuran, and 0.22 mol of butadiene were added to a 250 mL three-necked flask equipped with a reflux condenser, a nitrogen inlet, and a mechanical stirrer. 100 mL of dry dimethyl sulfoxide was added, and nitrogen was purged for 30 min to remove oxygen. The mixture was then heated to 80 °C and 0.20 g of azobisisobutyronitrile (AIBN) was injected in one go. The mixture was stirred at 500 rpm for 5 h under nitrogen protection to complete the free radical copolymerization. After the reaction was completed, the system was cooled to room temperature, and 0.13 mol of bromomethane (dissolved in 20 mL of anhydrous ethanol) was slowly added dropwise. The temperature was maintained at 30 °C and the reaction was continued for 3 h to complete the quaternization. The solvent and residual bromomethane were then removed by vacuum distillation. The mixture was precipitated with acetone and dried under vacuum to obtain the quaternary ammonium salt cationic polymer segments.

[0039] S2: 3-Dimethylaminoneopentyl acrylate (0.11 mol), 2-vinylfuran (0.11 mol), and butadiene (0.35 mol) were subjected to free radical copolymerization at 80 °C and 0.16 g AIBN for 5 h under the same operation. Sodium benzenesulfonate maleimide (0.055 mol, same as in Example 1) was then added to the reaction system in one go. The temperature was raised to 85 °C and stirred for 8 h to complete the Diels-Alder reaction. After the reaction was completed, the solvent was removed under reduced pressure. Salt impurities were removed by recrystallization twice with ethanol-water (volume ratio 1:2). The sulfonate anionic polymer segments were obtained by vacuum drying.

[0040] S3: The above-mentioned quaternary ammonium salt cationic polymer segments and sulfonate anionic polymer segments were accurately weighed in an equimolar ratio (based on the molar charge of the quaternary ammonium salt and sulfonate) and added together to a mixed solvent of ethanol / dimethyl sulfoxide (volume ratio 1:1) (the mass percentage of solute was 35%, and the total mass was 100g). The mixture was stirred at 85°C for 4 hours to complete ion pairing. Then, acetone was added dropwise for recrystallization and the mixture was filtered. The mixture was washed three times with acetone and dried under vacuum at 65°C for 15 hours to obtain a pure ion-paired polymer.

[0041] S4: Add multi-walled carbon nanotubes (3.4g, same as in Example 1) to 35mL of dimethyl sulfoxide and sonicate for 35min. Then add the above-mentioned ion-pair polymer (4.2g) and dextrin fatty acid ester (0.5g), sonicate for 50min and mechanically stir at 700rpm to obtain a uniform and highly dispersed carbon nanotube suspension.

[0042] Example 4

[0043] The preparation method of the highly dispersible carbon nanotube suspension in this embodiment is basically the same as that in Example 1 in terms of raw material composition and preparation steps. The difference is that in the preparation method of this embodiment, 3-(dimethylamino)propyl methacrylate is used instead of 3-(dimethylamino)propyl acrylate.

[0044] Example 5

[0045] The preparation method of the highly dispersible carbon nanotube suspension in this embodiment is basically the same as that in Example 1 in terms of raw material composition and preparation steps. The difference is that in the preparation method of this embodiment, 2-furan carboxylic acid allyl ester is used instead of 2-vinyl-5-methylfuran.

[0046] Comparative Example 1

[0047] The preparation method of the carbon nanotube suspension in this comparative example is basically the same as that in Example 1 in terms of raw material composition and preparation steps. The difference is that step S1 is not included in the preparation method of this comparative example.

[0048] Comparative Example 2

[0049] The preparation method of the carbon nanotube suspension in this comparative example is basically the same as that in Example 1 in terms of raw material composition and preparation steps. The difference is that step S2 is not included in the preparation method of this comparative example.

[0050] The carbon nanotube suspensions prepared in Examples 1-5 and Comparative Examples 1-2 were subjected to performance tests, and the performance results are shown in Table 1.

[0051] The initial viscosity was determined according to GB / T 2794. The specific operating steps are as follows: After the suspension was kept at a constant temperature (25±0.5℃) for 5 minutes, 50 mL of sample was injected into the NDJ-5S rotational viscometer. Rotor No. 2 was selected, the rotation speed was 60 rpm, and the value was read after 30 seconds of stabilization.

[0052] The determination of the settling rate was carried out in accordance with GB / T 6753.3; the specific operation steps are as follows: 100 mL of suspension was put into a graduated 100 mL graduated cylinder, sealed and left to stand at 25℃ in the dark for 30 days, the volume of the supernatant was measured, and the settling rate was calculated as (volume of supernatant / total volume) × 100%.

[0053] The redispersion time was determined according to ISO 8781; the specific operating steps are as follows: the sample after standing for 30 days was placed in an ultrasonic cleaner (power 300W, frequency 40kHz), ultrasonicated at 25℃ and mechanically stirred at 600rpm at the same time, and the time required from start to visually complete homogenization was recorded.

[0054] The determination of performance retention rate (viscosity, conductivity) after thermal cycling is based on GB / T 2423.22; the specific operating steps are as follows: 50 mL of suspension is sealed in a polytetrafluoroethylene bottle and placed in a programmable high and low temperature chamber. Set −40℃×30 min←→85℃×30 min as one cycle, and repeat for 50 cycles. After the cycle, equilibrate at 25℃ for 2 h, then measure the viscosity according to the above initial viscosity test method, and measure the conductivity according to GB / T 11007 "Method for Determination of Conductivity". Calculate the retention rate = (value after cycling / initial value) × 100%.

[0055] The tensile strength is improved after compounding with rubber, and the determination is carried out according to GB / T 528. The specific operation steps are as follows: the suspension is added at a rate of 3 phr (per 100 parts of rubber) and NBR rubber is compounded in a two-roll mill, vulcanized according to GB / T 6038 (160℃×15min), and 2mm dumbbell-shaped specimens are prepared; tensile strength is recorded at 500 mm / min on a universal testing machine; compared with blank vulcanized rubber, the improvement rate is calculated as [(experimental group strength − blank group strength) / blank group strength]×100%.

[0056] Table 1

[0057] project Initial viscosity (mPa·s, 25℃) Settling rate (%) after 30 days of standing Redispersal time (s) Viscosity retention rate (%) after 50 cycles of hot and cold cycling Conductivity retention rate (%) after 50 cycles of thermal cycling Tensile strength increased by (%) after compounding with rubber Example 1 1850 0.7 18 96 94 28 Example 2 1920 0.6 20 95 93 26 Example 3 1780 0.8 22 97 95 27 Example 4 1870 0.7 19 96 94 29 Example 5 1900 0.6 21 95 93 25 Comparative Example 1* 2400 12.3 >120 68 61 11 Comparative Example 2* 2350 14.1 >150 65 58 9

[0058] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A method for preparing a highly dispersible carbon nanotube suspension, characterized in that, The preparation method includes the following steps: S1: Dimethylaminoacrylate, furanyl olefin and butadiene are mixed in a first ratio and subjected to free radical copolymerization in the presence of a free radical initiator; after the reaction is completed, bromomethane is added to the system to carry out quaternization reaction to obtain quaternary ammonium salt cationic polymer segments; S2: Dimethylaminoacrylate, furanyl olefin and butadiene are mixed in a second ratio and subjected to free radical copolymerization in the presence of a free radical initiator; then sodium benzenesulfonate maleimide is added to the reaction system to carry out Diels-Alder reaction to obtain sulfonate anionic polymer segments; S3: Disperse the quaternary ammonium salt cationic polymer segments obtained in step S1 and the sulfonate polymer anionic segments obtained in step S2 in a mixed solvent at an equimolar ratio, heat and stir for 2-6 hours to achieve full ion pairing; remove by-product salt impurities after separation, and obtain pure ion-paired polymer after vacuum drying. S4: Carbon nanotubes, the ion-pair polymer obtained in step 3, organic thixotropic wax and polar organic solvent are compounded in proportion and then fully dispersed to obtain the highly dispersed carbon nanotube suspension.

2. The method for preparing the highly dispersed carbon nanotube suspension as described in claim 1, characterized in that, The dimethylamino acrylate is at least one of 3-(dimethylamino)propyl acrylate, 3-dimethylaminoneopentyl acrylate, 3-(dimethylamino)propyl methacrylate, and 2-dimethylaminoethyl methacrylate.

3. The method for preparing the highly dispersed carbon nanotube suspension as described in claim 1, characterized in that, The furanyl olefin is at least one selected from 2-vinyl-5-methyl-furan, 2-vinylfuran, allyl 2-furancarboxylate, and 3-(2-furanyl)propyl acrylate.

4. The method for preparing the highly dispersed carbon nanotube suspension as described in claim 1, characterized in that, In step S1, the molar ratio of dimethylaminoacrylate, furanyl olefin and butadiene is 1-3:1:2-5.

5. The method for preparing the highly dispersed carbon nanotube suspension as described in claim 1, characterized in that, The preparation method of sodium benzenesulfonate maleimide is as follows: furan and maleic anhydride in a molar ratio of 1:1 are dissolved in excess 1,4-dioxane. After the reaction, the product is dissolved in methanol with sodium p-aminobenzenesulfonate under ice bath conditions. The mixture is heated to 60-80°C and stirred to react. Then, the product is added to toluene and refluxed at 120-150°C. After separation, the sodium benzenesulfonate maleimide is obtained.

6. The method for preparing the highly dispersed carbon nanotube suspension as described in claim 1, characterized in that, In step S2, the molar ratio of dimethylaminoacrylate, furanyl olefin and butadiene is 1:1 to 3:2 to 5.

7. The method for preparing the highly dispersed carbon nanotube suspension as described in claim 1, characterized in that, The molar amount of furanyl olefin in step S2 is equal to the molar amount of dimethylamino acrylate in step 1.

8. The method for preparing the highly dispersed carbon nanotube suspension as described in claim 1, characterized in that, The organic thixotropic wax is at least one of hydrogenated castor oil, polyamide wax, or dextrin fatty acid ester.

9. The method for preparing the highly dispersed carbon nanotube suspension as described in claim 1, characterized in that, The polar organic solvent is at least one of N-methylpyrrolidone, dimethyl sulfoxide, or N,N-dimethylformamide.

10. A highly dispersible carbon nanotube suspension, characterized in that, The carbon nanotube suspension is prepared using the method for preparing a highly dispersed carbon nanotube suspension as described in any one of claims 1 to 9.