CN111606318A - Method for deagglomerating and dispersing carbon nanotubes mechanically by wet method - Google Patents

Method for deagglomerating and dispersing carbon nanotubes mechanically by wet method Download PDF

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CN111606318A
CN111606318A CN201910132539.5A CN201910132539A CN111606318A CN 111606318 A CN111606318 A CN 111606318A CN 201910132539 A CN201910132539 A CN 201910132539A CN 111606318 A CN111606318 A CN 111606318A
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carbon nanotubes
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carbon nano
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CN111606318B (en
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张经纬
庞凯祥
赵方
张文豪
张纪伟
龚春红
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Henan University
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Abstract

The invention provides a method for deagglomerating and dispersing carbon nanotubes by a wet method and machinery, which comprises the following steps: A) dispersing carbon nano tubes in a solution to obtain a mixed system, and adjusting the temperature of the mixed system to enable part of solvent or solute to generate controllable liquid/solid phase transformation to obtain a solid/liquid two-phase flow system with periodically and dynamically changed solid content; B) and applying mechanical force in the system to deagglomerate the carbon nano tubes to obtain a well-dispersed high-quality carbon nano tube dispersion liquid. The invention obtains the carbon nano tube with good dispersion by deagglomerating the carbon nano tube at a specific temperature and in a liquid phase environment. The preparation process has no toxic organic additives and the like, is green and environment-friendly, has low cost, simple process, high production efficiency, good dispersion stability, cheap equipment, easy scale amplification and the like. The carbon nano tube dispersion liquid prepared by the invention has good application prospect.

Description

Method for deagglomerating and dispersing carbon nanotubes mechanically by wet method
Technical Field
The invention relates to the technical field of materials, in particular to a method for dispersing carbon nanotubes by wet mechanical deagglomeration.
Background
Since the discovery of carbon nanotubes, the research on carbon nanotubes in the fields of physics, chemistry, materials, biology, information, etc. has been growing in geometric progression. The carbon nano tube has excellent physical, chemical, electronic and optical properties and has potential application prospect in a plurality of fields. The carbon nanotubes can be regarded as a curled graphene sheet, so that the carbon nanotubes have the intrinsic characteristics of graphite and graphene, such as high heat resistance, corrosion resistance, thermal shock resistance, high-temperature strength, self-lubricity and biocompatibility, and also have high tensile strength, and are the strongest fibers; the conductive material has excellent axial conductivity and is a good one-dimensional quantum wire; the axial heat exchange performance is good, the radial heat exchange performance is poor, and the material is an ideal anisotropic heat conduction material; the hollow structure makes it possess considerable hydrogen storing performance and is also ideal catalyst carrier material. Although carbon nanotubes have great application potential in many application fields, carbon nanotubes generally exhibit an entangled aggregation state due to their large aspect ratio and large specific surface area. At present, how to obtain carbon nanotubes with good dispersion is still the key to restrict the commercial application of the carbon nanotubes.
Although there are some methods for dispersing carbon nanotubes, such as ball milling, ultrasonic dispersion, and strong acid and alkali treatment. However, the existing dispersion technology has serious damage to the structure of the carbon nanotube itself. Such as a strong acid treatment method commonly used in scientific research, a hydrophilic carbon nanotube with certain dispersibility can be obtained. However, in this method, when the carbon nanotube is subjected to a strong acid treatment, the outer wall of the tube is oxidized to have a certain amount of functional groups. Although most functional groups can be removed by high-temperature treatment, the residual defects are permanent and difficult to completely recover, the carbon nanotube dispersion liquid with high quality and few defects is difficult to prepare, dangerous chemicals are needed in the preparation process, a large amount of waste liquid is generated, and the production process does not conform to the development direction of green chemical industry; the high ball milling method is another common method for dispersing carbon nanotubes, but the high energy input can cause the carbon nanotubes to break, the length-diameter ratio to decrease, and the stress concentration can cause the dispersed short carbon nanotubes to be bonded to form small aggregates again. Other methods for dispersing carbon nanotubes also have certain limitations and disadvantages, and it is difficult to effectively prepare high-quality, high-concentration and stably dispersed carbon nanotubes.
Therefore, the development of an environmentally friendly preparation process to achieve high-efficiency, low-cost dispersion of high-quality carbon nanotubes is a prerequisite for the realization of commercial applications of carbon nanotubes. The method of applying mechanical force as a means for dispersing the carbon nanotubes can greatly avoid the generation of defects of the carbon nanotubes and the use of high-risk chemicals. Studies have shown that the application of mechanical forces and the nature of the solvent have a significant effect on the dispersion. The dispersion of carbon nanotubes is generally divided into two stages: deagglomeration of large agglomerates and dispersion of bundles of small carbon nanotubes. There are relatively many methods to break up large agglomerates of carbon nanotubes into small bundles of nanotubes, such as ball milling, ultrasonic dispersion, high speed shearing, etc. However, the further dispersion of the small carbon nanotube bundles still is a limitation to the carbon nanotubes which can exert their excellent physicochemical properties.
According to Newton's law of viscosity, when the mixed fluid is in laminar flow state, due to viscous action, there is flow speed difference delta v between two internal and external contact surfaces of the particle and solution in the solution, and in a certain range, the flow speed difference delta v between two contact surfaces and distance delta x between two contact surfaces of the particlenThe correlation is linear. At this time, the material is subjected to a stress F ═ k1Δxn＝k2Δvn. Where n is the rheological index, n ≠ 1 for newtonian fluids, n ≠ 1 for non-newtonian fluids; k is a radical of1，k2The linear correlation coefficients of F and delta x and delta v are respectively, and are positively correlated with the viscosity η of the system in a certain viscosity range, in the process of dispersing the small carbon nanotube bundle, when the included angle between the carbon nanotube and the stress direction is theta, the carbon nanotube is subjected to shearing force Fcos theta and tensile stress Fsin theta, and in the process of dispersing the carbon nanotube, the shearing force Fcos theta and the tensile stress Fsin theta are carried out along with the dispersion of the carbon nanotubeThe reduction in the diameter of the bundle, i.e. the reduction in ax, av, is also accompanied by a corresponding reduction in the force F. Generally, when the carbon nanotubes are subjected to a shearing force Fcos θ smaller than the friction force f between the carbon nanotube bundles, or a tensile force Fsin θ smaller than the van der waals force between the carbon nanotube bundles, the carbon nanotube dispersion efficiency is rapidly decreased, so that the dispersion degree is not high. Therefore, the traditional method for dispersing the carbon nano tube by mechanical force has certain limitation and is difficult to achieve higher dispersion degree. To increase the degree of dispersion, generally by increasing the energy input or increasing the viscosity of the solution, increases costs and difficulties are favoured; another method is to oxidize or functionalize the small carbon nanotube bundles, but these destroy the structure of the carbon nanotubes themselves and cause defects that are almost impossible to recover, which limits their commercial application.
Disclosure of Invention
In view of the above, the technical problem to be solved by the present invention is to provide a method for dispersing carbon nanotubes by wet mechanical deagglomeration, which has the advantages of low cost, simple process, high production efficiency, high dispersion stability of the product and fewer defects.
The invention provides a method for deagglomerating and dispersing carbon nanotubes by a wet method and machinery, which comprises the following steps:
dispersing carbon nano tubes in a solution to obtain a mixed system, and adjusting the temperature of the mixed system to enable part of solvent or solute to generate controllable liquid/solid phase transformation to obtain a solid/liquid two-phase flow system with periodically and dynamically changed solid content; and applying mechanical force in the system to deagglomerate the carbon nano tubes to obtain the well-dispersed carbon nano tube dispersion liquid. The temperature range of the mixed system can be set according to the following principle: the solute saturated precipitation system is X + 20-X-20; the temperature of the mixed system is X + 5-X-5 relative to the solvent condensation crystal system. Preferably, the carbon nanotubes are selected from one or more of single-walled carbon nanotubes, double-walled carbon nanotubes and multi-walled carbon nanotubes.
Preferably, the solution comprises one or more of an organic solvent, a surfactant, a soluble polymer and a soluble solid.
Preferably, the organic solvent is selected from one or more of N-alkyl-pyrrolidones, amides, alcohols, ketones, pyridine, N-formylpiperidine, 1, 3-dimethyl-2-imidazolidinone, N-methylmorpholine-N-oxide, bromobenzene, benzonitrile, benzyl benzoate, N-dimethylpropyleneurea, γ -butyrolactone, DMSO, dibenzyl ether, chloroform, chlorobenzene, 1-3 dioxolane, ethyl acetate, quinoline, benzaldehyde, diethyl phthalate, dimethyl phthalate, vinyl acetate, water, ammonia, and carbon dioxide;
the surfactant is selected from one or more of sodium alginate, sodium cholate, lithium dodecyl sulfate, sodium dodecyl benzene sulfonate, tetraethylammonium hydroxide, hexadecyl trimethyl ammonium bromide, deoxycholate, taurodeoxycholate, polyoxyethylene (40) nonylphenyl ether, branched (IGEPAL CO-890) and polyethylene glycol p- (1, 1,3, 3-tetramethylbutyl) phenyl ether (Triton-x 100 (TX-100));
the soluble polymer is selected from one or more of polyethylene glycol, polyvinyl alcohol, polyvinylpyrrolidone, polybutadiene, styrene-butadiene copolymer, polystyrene, polyvinyl chloride, polyvinyl acetate, polycarbonate, polymethyl methacrylate, polyvinylidene fluoride, polyvinylidene chloride, cellulose acetate, polyimide, acrylate rubber, polyisocyanate resin and polyvinyl butyral;
the soluble solid is selected from one or more of urea, chloride, carbonate, sulfate, hydroxide and phosphate.
Preferably, the stripping temperature is 50 ℃ to-50 ℃; the stripping time is 0.5-16 h.
Preferably, the temperature of the mixed system for the solute saturated precipitation system is X + 20-X-20, wherein X is the precipitation temperature of the solute; the temperature of the mixed system for the solvent condensation crystallization system is X + 5-X-5, wherein X is the freezing point temperature.
Preferably, the mechanical force is selected from one or more of high-speed shearing, mechanical stirring and high-pressure jet flow.
Preferably, when the mechanical force is mechanical stirring, the stirring speed is 100-2000 rpm, and the stirring time is 8-16 h.
Preferably, when the mechanical force is high-speed shearing, the stirring rotating speed is 2000-24000 rpm; the stirring time is 0.5-12 h.
Preferably, the ratio of the mass of the carbon nanotube to the solvent is (1): (25-250).
Compared with the prior art, the invention provides a method for dispersing carbon nanotubes by wet mechanical deagglomeration, which comprises the following steps: A) dispersing carbon nano tubes in a solution to obtain a mixed system, and adjusting the temperature of the mixed system to enable part of solvent or solute to generate controllable liquid/solid phase transformation to obtain a solid/liquid two-phase flow system with periodically and dynamically changed solid content; B) and applying mechanical force in the system to deagglomerate the carbon nano tubes to obtain the well-dispersed carbon nano tube dispersion liquid. The invention obtains the carbon nano tube with good dispersion by deagglomerating the carbon nano tube at a specific temperature and in a liquid phase environment. The preparation method has the advantages of no toxic organic additives and the like in the preparation process, environmental protection, low cost, simple process, high production efficiency, good dispersion stability, cheap equipment, easy scale amplification and the like. The carbon nano tube dispersion liquid prepared by the invention has good application prospect.
Drawings
FIG. 1 is a photograph showing the optical contrast between the multi-walled carbon nanotubes and dimethyl phthalate in example 1 before and after dispersion;
FIG. 2 is a graph of the test stability analysis of the product of example 2;
FIG. 3 is a scanning electron microscope image of the electrode sheet obtained by coating the copper foil and drying after the product of example 3 is compounded with silicon;
FIG. 4 is an optical photograph of a sample after dilution by 400 times of the product of example 4 and an ultraviolet absorption spectrum;
FIG. 5 is a comparative scanning electron microscope image of carbon nanotubes before and after dispersion in example 5;
FIG. 6 is a Raman test analysis of the product of example 6.
Detailed Description
The invention provides a method for deagglomerating and dispersing carbon nanotubes by a wet method and machinery, and a person skilled in the art can appropriately improve process parameters by referring to the content. It is expressly intended that all such similar substitutes and modifications apparent to those skilled in the art are deemed to be within the scope of the invention. While the methods and applications of this invention have been described in terms of preferred embodiments, it will be apparent to those of ordinary skill in the art that variations and modifications in the methods and applications described herein, as well as other suitable variations and combinations, may be made to implement and use the techniques of this invention without departing from the spirit and scope of the invention.
The invention provides a method for deagglomerating and dispersing carbon nanotubes by a wet method and machinery, which comprises the following steps:
A) dispersing carbon nano tubes in a solution to obtain a mixed system, and adjusting the temperature of the mixed system to enable part of solvent or solute to generate controllable liquid/solid phase transformation to obtain a solid/liquid two-phase flow system with periodically and dynamically changed solid content;
B) and applying mechanical force in the system to deagglomerate the carbon nano tubes to obtain the well-dispersed carbon nano tube dispersion liquid.
The method for dispersing the carbon nano tube by wet mechanical deagglomeration firstly disperses the carbon nano tube in a solution to obtain a mixed system.
The carbon nano tube is selected from one or more of single-wall carbon nano tube, double-wall carbon nano tube and multi-wall carbon nano tube.
The source of the carbon nanotubes in the present invention is not limited, and those known to those skilled in the art may be commercially available.
The method of dispersing the carbon nanotubes in the solution is not limited in the present invention, and those skilled in the art will be familiar with the method.
The solution of the invention is a single solvent or a mixed solution which is liquid at normal temperature, and can also be a single solvent or a mixed solution which is gas or solid at normal temperature and is converted into liquid by changing temperature or pressure.
The solution of the invention preferably comprises one or more of organic solvent, surfactant, soluble polymer and soluble solid; preferably comprises two or more of an organic solvent, a surfactant, a soluble polymer and a soluble solid;
wherein, the organic solvent is preferably selected from one or more of N-alkyl-pyrrolidone, amide, alcohol, ketone, pyridine, N-formylpiperidine, 1, 3-dimethyl-2-imidazolidinone, N-methylmorpholine, N-methylmorpholine-N-oxide, bromobenzene, benzonitrile, benzyl benzoate, N-dimethylpropyleneurea, gamma-butyrolactone, DMSO, dibenzyl ether, chloroform, chlorobenzene, 1-3 dioxolane, ethyl acetate, quinoline, benzaldehyde, diethyl phthalate, dimethyl phthalate, vinyl acetate, water, ammonia and carbon dioxide;
the surfactant is preferably selected from one or more of sodium alginate, sodium cholate, lithium dodecyl sulfate, sodium dodecyl benzene sulfonate, tetraethylammonium hydroxide, hexadecyl trimethyl ammonium bromide, deoxycholate, taurodeoxycholate, polyoxyethylene (40) nonylphenyl ether, branched (IGEPAL CO-890) and polyethylene glycol p- (1, 1,3, 3-tetramethylbutyl) phenyl ether (Triton-x 100 (TX-100));
the soluble polymer comprises thermoplastic resin, thermosetting resin, elastomer and natural polymer which can be dissolved in a proper solvent, preferably one or more selected from polyethylene glycol, polyvinyl alcohol, polyvinylpyrrolidone, polybutadiene, styrene-butadiene copolymer, polystyrene, polyvinyl chloride, polyvinyl acetate, polycarbonate, polymethyl methacrylate, polyvinylidene fluoride, polyvinylidene chloride, cellulose acetate, polyimide, acrylate rubber, polyisocyanate resin and polyvinyl butyral;
the soluble solid is preferably selected from one or more of urea, chloride, carbonate, sulfate, hydroxide and phosphate.
The source of the solution is not limited in the present invention, and may be commercially available as is well known to those skilled in the art.
After the mixed system is obtained, the temperature of the mixed system is adjusted to enable part of the solvent to generate controllable liquid/solid phase transformation, and a solid/liquid two-phase flow system with dynamically changed solid content is obtained.
The temperature range of the mixed system is X + 20-X-20 for a solute saturated precipitation system; wherein X is the solute precipitation temperature; the temperature of the mixed system is X + 5-X-5 relative to the solvent condensation crystal system; wherein X is the freezing point temperature of the mixed system.
Wherein, the solute saturated precipitation system is a system containing one or more of soluble polymers and soluble solid materials, and the solid content change is mainly precipitation/dissolution between solid and liquid phases of the soluble materials; the solvent condensation crystal system is a system without soluble polymer and soluble solid, and solid content change is mainly solid-liquid interphase solidification/melting of the solvent.
By adjusting the temperature of the system, the state of the system is changed, and part of the solvent undergoes controllable liquid/solid phase transition, such as solid-liquid-solid or liquid-solid-liquid transition, so that a solid/liquid two-phase flow system with dynamically changed solid content is constructed, the viscosity of the system and the solid content are periodically increased, and the deagglomeration dispersion efficiency is obviously improved.
The invention carries out shearing deagglomeration and dispersion on the carbon nano tube in a specific solvent system. Within the specific temperature range, the method can enhance the shearing and deagglomeration dispersion effect of the mechanical force on the carbon nano tube, and the prepared carbon nano tube dispersion liquid has the characteristic of stable dispersion under high concentration.
The mechanical force of the present invention is preferably selected from one or more of high speed shearing, mechanical stirring, ball milling and high pressure jet. The deagglomeration and dispersion process can be operated in batch mode or continuous mode.
The manner or apparatus of applying the mechanical force is not limited in the present invention and is well known to those skilled in the art; including but not limited to: mechanical stirring machine, high-speed homogenizer, high-pressure homogenizer, cooking machine and high-speed emulsification dispersion machine.
According to the invention, when the mechanical force is mechanical stirring, the stirring speed is 100-2000 rpm, and the stirring time is 8-16 h; when the mechanical force is high-speed shearing, the stirring rotating speed is 2000-24000 rpm; the stirring time is 0.5-12 h.
Wherein, the de-agglomeration temperature is selected according to the invention and is related to the selected solvent solidification temperature/salt precipitation temperature, and different solution systems have different temperatures.
The inventors have found that the longer the exfoliation time is at a suitable shear rate around the freezing point of the system, the more uniform the dispersion of the resulting carbon nanotubes.
The stirring speed is different according to the selection of the solvent and the selection of different material ratios, such as: stirring and dispersing the single-walled carbon nanotubes in NMP, and selecting 400rpm for 12 hours; and shearing and dispersing the multi-wall carbon nano-tube in a supersaturated urea system, and selecting 11000rpm for 4 h.
The ratio of the mass of the carbon nanotubes to the solution is preferably 1: (20-300); more preferably 1: (25-250). The selection of the mass ratio of the raw materials is related to the type of the carbon nanotube. For example, the mass to solution ratio selected for dispersing high purity single wall carbon nanotubes is preferably 1: (200-300); the mass to solution ratio selected for the dispersed multi-walled carbon nanotubes is preferably 1: (20 to 100)
The viscosity change range in the dispersion process directly influences the torque under a certain volume, and the change of the torque under the same volume and the same rotating speed is essentially the change of the viscosity of the internal slurry. Specifically, the torque of the mixed system is 1-4N-cm under the volume of 100 ml; the torque of the mixed system is 2-15N-cm under the volume of 500 ml; under the volume of 1L, the torque of the mixing system is 3-40N-cm, namely the torque changes in a set temperature range and changes along with the change of temperature, and of course, the torque also changes along with the change of the type, the size and the stirring parameters of the stirring paddle.
In the set temperature range, the soluble compound is continuously separated out, dissolved out and separated out in the dispersion process.
When the polymer monomer is selected as the solvent to disperse the carbon nano tube, the polymer monomer can be induced to polymerize after the dispersion is finished, and the polymer-based composite material can be obtained.
And (3) selectively adding the nano particles after the carbon nano tubes are dispersed, and obtaining the dispersion liquid with the carbon nano tubes and the nano particles uniformly mixed after the dispersion is finished.
The stable dispersed carbon nanotube can be obtained by adding the stabilizer after the dispersion of the carbon nanotube dispersion liquid is finished.
The present invention is not limited to the specific kind of the stabilizer, and those skilled in the art are familiar with the stabilizer, for example, polyvinylidene fluoride may be added, and the addition ratio thereof is preferably 5: (1 to 3)
The carbon nano tube dispersion liquid finally prepared after stripping has high concentration, less defects and stable dispersion.
The invention provides an efficient, green and environment-friendly method for deagglomerating and dispersing carbon nanotubes by a wet method, which can be used for realizing efficient dispersion by applying mechanical force under the condition of not pretreating original carbon nanotubes to obtain high-concentration stable dispersion liquid. If a proper stabilizing agent is added, the maximum dispersion concentration and the dispersion stability of the product can be further improved. The carbon nano tube can also be directly dispersed in a proper polymer system to prepare the polymer-based composite material.
Research shows that the carbon nano tube needs to involve two stages in the dispersing process, namely deagglomeration of large aggregates and dispersion of small carbon nano tube bundles. The carbon nanotube dispersing process and possible principle are summarized as follows:
deagglomeration process for bulk agglomerates: during the solvent solidification/melting or solute precipitation/dissolution process, a large number of solid particles are periodically generated. Under the action of applied mechanical force, the solid particles are difficult to grow into a macroscopic block structure, and most of the solid particles still exist in the form of fine particles. The presence of a large number of precipitated/crystallized particles acts like media milling and ball milling to de-agglomerate the bulk carbon nanotube agglomerates.
The dispersion process for the small carbon nanotube bundle is as follows: for the small carbon nanotube bundle with the length-diameter ratio, under the condition of applying mechanical force, the small carbon nanotube is oriented along the flowing direction due to the flow speed difference, the viscosity of the system is increased, and solid particles attached to the wall of the carbon nanotube are present, so that the flow speed difference between two sides of the wall of the tube is increased, the stress of the carbon nanotube is increased, and the carbon nanotube is more easily dropped from the tube bundle. In order to further illustrate the present invention, the following describes a method for preparing a two-dimensional material by wet mechanical stripping according to the present invention in detail with reference to the following examples.
Example 1
The specific preparation process of the embodiment comprises the following steps: 8g of original multi-walled carbon nanotubes are dispersed in 400mL of dimethyl phthalate to prepare a mixed solution, and the mixed solution is transferred to a double-layer reaction kettle.
The double-layer reaction kettle is externally connected with a low-temperature cooling liquid circulating pump to adjust the temperature of the system to control the temperature to be close to the freezing point of 2 ℃, and then a mechanical stirrer is used for stirring and dispersing for 8 hours at 500 rpm.
After the stirring is finished, the dimethyl phthalate dispersion liquid of the multi-walled carbon nano-tube can be obtained
FIG. 1 is a photograph showing the optical contrast between the multi-walled carbon nanotubes and dimethyl phthalate in example 1 before and after dispersion. The change of the carbon nanotubes from the bulk agglomerated state to the uniformly dispersed state after dispersion can be known by comparison.
Example 2
The specific preparation process of the embodiment comprises the following steps: 12g of original multi-walled carbon nano-tubes are dispersed in 400mLN, N-dimethylaniline to prepare a mixed solution, and the mixed solution is transferred into a double-layer reaction kettle.
The double-layer reaction kettle is externally connected with a low-temperature cooling liquid circulating pump to adjust the temperature of the system to control the temperature to be close to the freezing point of 20 ℃ below zero, and then a mechanical stirrer is used for stirring and dispersing for 15 hours at 500 rpm.
Obtaining the DMA dispersion liquid of the multi-walled carbon nano-tube after the stirring is finished
FIG. 2 is a graph of the product stability data from example 2 at 1000rpm for 20000 s. From the results, it was found that the transmittance did not increase in the whole of the dispersion in the portion of 108mm or less of the liquid surface after centrifugation at 1000rpm for 20000s, and it was found that the carbon nanotubes subjected to the dispersion treatment were stably dispersed and no significant sedimentation occurred.
Example 3
The specific preparation process of the embodiment comprises the following steps: 4g of single-walled carbon nanotubes are dispersed in 400mL of N-methylpyrrolidone to prepare a mixed solution, and the mixed solution is transferred to a double-layer reaction kettle.
The double-layer reaction kettle is externally connected with a low-temperature cooling liquid circulating pump to adjust the temperature of the system to control the temperature to be close to the freezing point of-24 ℃, and then a mechanical stirrer is used for stirring and dispersing for 8 hours at 500 rpm.
And (3) after the dispersion process is finished, adding polyvinylidene fluoride (hsv900) serving as a lithium battery binder into the slurry, and uniformly stirring and dispersing to obtain the high-quality dispersed carbon nanotube dispersion liquid capable of being used as a lithium battery.
FIG. 3 is a scanning electron microscope image of the composite electrode sheet prepared by coating copper foil with the product of example 3 after being compounded with nano-silicon spheres, and it can be seen from FIG. 3 that single-walled carbon nanotubes are uniformly dispersed in the electrode sheet with nano-silicon spheres and polyvinylidene fluoride as active substances.
Example 4
The specific preparation process of the embodiment comprises the following steps: 1.6g of single-walled carbon nanotubes were dispersed in 400mL of NMP to prepare a mixed solution, which was transferred to a double-layer reaction vessel.
The double-layer reaction kettle is externally connected with a low-temperature cooling liquid circulating pump to adjust the temperature of the system to control the temperature to be close to the freezing point of-24 ℃, and then a mechanical stirrer is used for stirring and dispersing for 10 hours at 500 rpm.
And (3) adding polyvinylidene fluoride (5130) into the slurry after the dispersion is finished, thus obtaining the carbon nanotube transparent conductive film coating meeting the commercial standard.
FIG. 4 is an optical photograph and an ultraviolet absorption spectrum of a sample obtained by diluting the product of example 4 by 400 times, and it can be seen from the inset in FIG. 4 that the carbon nanotubes are well dispersed by mechanical stirring, and the absorption value of the diluted dispersion at 500nm is 0.482, which is higher than the standard value of the commercial carbon nanotube transparent conductive film coating, which is 0.45.
Example 5
The specific preparation process of the embodiment comprises the following steps: dispersing 10g of multi-walled carbon nano-tube in 400mL of dimethyl sulfoxide to prepare a mixed solution, adding 2g of sodium cholate, and transferring the mixed solution to a double-layer reaction kettle.
The double-layer reaction kettle is externally connected with a low-temperature cooling liquid circulating pump to adjust the temperature of the system to control the temperature to be close to the freezing point of 18 ℃, and then a mechanical stirrer is used for stirring and dispersing for 16 hours at 400 rpm.
And washing and freeze-drying the product, and sampling and taking a scanning electron microscope picture.
Fig. 5 is a scanning electron microscope picture of the product, and it can be seen from fig. 5 that the state of multi-bundle aggregation of the carbon nanotubes is solved and the state of single bundle or few bundles of the carbon nanotube bundles is formed by de-aggregation of the carbon nanotube bundles.
Example 6
The specific preparation process of the embodiment comprises the following steps: 0.8g of single-walled carbon nanotubes was dispersed in 400mL of a 0.4 wt% aqueous polyvinylpyrrolidone solution, and 20mL of t-butanol was added to the mixture and transferred to a two-layer reaction vessel.
The double-layer reaction kettle is externally connected with a low-temperature cooling liquid circulating pump to adjust the temperature of the system to control the temperature to be near freezing point-5 ℃, and then a mechanical stirrer is used for stirring and dispersing for 12 hours at 400 rpm.
Fig. 6 is a raman test analysis chart of the product of example 6, and it can be seen that no obvious D peak appears in the raman chart of the single-walled carbon nanotube before and after dispersion after the dispersion treatment, which indicates that no structural defect is introduced when the single-walled carbon nanotube is dispersed.
Example 7
The specific preparation process of the embodiment comprises the following steps: 0.8g of single-walled carbon nanotubes was dispersed in 400mL of a 0.1 wt% aqueous solution of carboxymethyl cellulose, and 20mL of t-butanol was added to the mixture and transferred to a two-layer reaction vessel.
The double-layer reaction kettle is externally connected with a low-temperature cooling liquid circulating pump to adjust the temperature of the system to control the temperature to be near the freezing point of 7 ℃ below zero, and then a mechanical stirrer is used for stirring for 12 hours at 400rpm, so that the well-dispersed single-walled carbon nanotube dispersion liquid can be obtained.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims (10)

1. A method for wet mechanical deagglomeration and dispersion of carbon nanotubes, comprising:
A) adding carbon nano tubes into the solution to obtain a mixed system, and adjusting the temperature of the mixed system to enable part of the solvent or solute to generate controllable liquid/solid phase transformation to obtain a solid/liquid two-phase flow system with periodically and dynamically changed solid content;
B) and applying mechanical force in the system to deagglomerate the carbon nano tubes to obtain the well-dispersed carbon nano tube dispersion liquid.
2. The method of claim 1, wherein the carbon nanotubes are selected from one or more of single-walled carbon nanotubes, double-walled carbon nanotubes, and multi-walled carbon nanotubes.
3. The method of claim 1, wherein the solution comprises one or more of an organic solvent, a surfactant, a soluble polymer, and a soluble solid.
4. The method according to claim 3, wherein the organic solvent is selected from one or more of N-alkyl-pyrrolidones, amides, alcohols, ketones, pyridine, N-cresolpiperidine, 1, 3-dimethyl-2-imidazolidinone, N-methylmorpholine, N-methylmorpholine-N-oxide, bromobenzene, benzonitrile, benzyl benzoate, N-dimethylpropyleneurea, Y-butyrolactone, DMSO, dibenzyl ether, chloroform, chlorobenzene, 1-3 dioxolane, ethanol acetate, quinoline, benzaldehyde, diethyl phthalate, dimethyl phthalate, vinyl acetate, water, ammonia, and carbon dioxide;
the surfactant is selected from one or more of sodium alginate, sodium cholate, lithium dodecyl sulfate, sodium dodecyl benzene sulfonate, tetraethylammonium hydroxide, hexadecyl trimethyl ammonium bromide, deoxycholate, taurodeoxycholate, polyoxyethylene (40) nonylphenyl ether, branched (IGEPAL CO-890) and polyethylene glycol p- (1, 1,3, 3-tetramethylbutyl) phenyl ether (Triton-x 100 (TX-100));
the soluble polymer is selected from one or more of polyethylene glycol, polyvinyl alcohol, polyvinylpyrrolidone, polybutadiene, styrene-butadiene copolymer, polystyrene, polyvinyl chloride, polyvinyl acetate, polycarbonate, polymethyl methacrylate, polyvinylidene fluoride, polyvinylidene chloride, cellulose acetate, polyimide, acrylate rubber, polyisocyanate resin and polyvinyl butyral;
the soluble solid is selected from one or more of urea, chloride, carbonate, sulfate, hydroxide and phosphate.
5. The method of claim 1, wherein the deagglomeration dispersion temperature is in the range of 50 ℃ to-50 ℃; the deagglomeration and dispersion time is 0.5-16 h.
6. The method according to claim 1, wherein the mixed system temperature is X +20 to X-20 for a solute saturated precipitation system, where X is the solute precipitation temperature; the temperature of the mixed system for the solvent condensation crystallization system is X + 5-X-5, wherein X is the freezing point temperature.
7. The method of claim 1, wherein the mechanical force is selected from one or more of high shear, mechanical agitation, ball milling, and high pressure jet.
8. The method according to claim 7, wherein the mechanical force is mechanical stirring, the stirring speed is 100-2000 rpm, and the stirring time is 4-16 h.
9. The method according to claim 7, wherein the stirring speed is 2000-24000 rpm when the mechanical force is high-speed shearing; the stirring time is 0.5-12 h.
10. The method of claim 1, wherein the ratio of the mass of the carbon nanotubes to the solvent is 1: (20-300).
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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114212773A (en) * 2021-12-17 2022-03-22 上海纳米技术及应用国家工程研究中心有限公司 Preparation method of carbon nanotube film
CN116425148A (en) * 2023-03-29 2023-07-14 清华大学 Orderly-arranged monodisperse carbon nano tube and preparation method thereof

Citations (1)

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CN103623719A (en) * 2013-12-18 2014-03-12 江苏科技大学 Method for dispersing carbon nanotubes in suspension

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103623719A (en) * 2013-12-18 2014-03-12 江苏科技大学 Method for dispersing carbon nanotubes in suspension

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114212773A (en) * 2021-12-17 2022-03-22 上海纳米技术及应用国家工程研究中心有限公司 Preparation method of carbon nanotube film
CN116425148A (en) * 2023-03-29 2023-07-14 清华大学 Orderly-arranged monodisperse carbon nano tube and preparation method thereof

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