阅读说明：本技术 易于分散的活性纳米碳粉末及其制备方法 (Easily dispersed active nano carbon powder and preparation method thereof ) 是由 王延青 郭明易 桑军 黄铮 于 2021-08-18 设计创作，主要内容包括：本发明公开了在有机溶剂中易分散的活性纳米碳粉末及其制备方法,得到的纳米碳粉末中的纳米碳的含量高,使用时在有机溶剂中再分散效果好,特别是非极性和弱极性有机溶剂中再分散效果好,制备工艺简单,可通过活性粉末状态进行储藏运输和销售,与传统的液体状态的微细纳米碳必须采用大量的溶剂进行储存和运输相比,储存和运输的成本更低,安全性能更好,更加经济环保。(The invention discloses active nano carbon powder which is easily dispersed in an organic solvent and a preparation method thereof, the obtained nano carbon powder has high content of nano carbon, good redispersion effect in the organic solvent during use, particularly good redispersion effect in nonpolar and weak polar organic solvents, simple preparation process, and can be stored, transported and sold in an active powder state.)

1. A preparation method of easily dispersible active nano carbon powder is characterized by comprising the following steps:

s1, mixing nano-carbon and a dispersing agent in a ball milling and nano-grinding mode, wherein the nano-carbon contains 50-95% by mass, the dispersing agent contains 5-50% by mass, and 0-5% of a stabilizing agent is added to obtain slurry containing micro nano-carbon;

s2, drying and secondarily grinding the fine nano-carbon slurry prepared in the step (1) to obtain solid activated carbon powder;

s3, continuously adopting the solid nano carbon powder in the step (2) to react with dopamine to generate a poly-dopamine coating layer;

after fully washing and drying, the surface of the obtained nano carbon powder is coated with a reactive polydopamine coating layer, wherein the mass percentage of polydopamine is 5-50%, and the nano carbon powder prepared by the step has good hydrophilicity and is easy to disperse in water;

s4, carrying out graft modification on the surface of polydopamine by adopting a sulfydryl or amino chain hydrocarbon compound containing 2-18 carbon atoms to obtain modified fine nano carbohydrate dispersed slurry;

and S5, drying the fine nano-carbon slurry prepared in the step (4) to obtain the activated carbon powder which can be well dispersed in a non-polar or low-polar solvent.

2. The method for producing an easily dispersible fine nanocarbon powder according to claim 1, characterized in that: the drying method is one or combination of low-temperature freeze drying, spray drying, fluidized bed drying, vacuum drying and rake drying.

3. The method for preparing easily dispersible activated nanocarbon powder according to claim 1, wherein: the fine nanocarbon slurry comprises 80-99% by mass of nanocarbon, 0.5-10% by mass of a dispersant and 0.5-10% by mass of nanocarbon.

4. The method for preparing easily dispersible activated nanocarbon powder according to claim 1, wherein: the nanocarbon comprises: the carbon nano-tube material is one or a mixture of a plurality of single-wall carbon nano-tubes (SWCNT), double-wall carbon nano-tubes (DWCNT), multi-wall carbon nano-tubes (MWCNT), Graphite (GR), fullerene (C60), Graphene (Graphene) or carbon black material (CB).

5. The method for preparing easily dispersible active nano carbon powder according to claim 1, characterized in that: the thickness of the polydopamine coating layer can be regulated and controlled according to the concentration of dopamine in a solution, and the thickness of the polydopamine coating layer is generally 0-5 nm.

6. The method for preparing easily dispersible active nano carbon powder according to claim 1, wherein the method comprises the following steps: the grafted may be a small molecule or a macromolecule, typically having 1 or more reactive groups such as: mercapto (-SH) or amino (-NH)₂). The grafting molecules can be selected according to the solvent needing to be dispersed, so that the effective regulation and control from water-soluble to oil-soluble dispersion are achieved.

7. The method for preparing easily dispersible activated nanocarbon powder according to claim 1 or 3, characterized in that: the dispersant includes, but is not limited to, one or more of Disponer 983, FA 196, FX 9086, polyacrylate, polyacrylamide, polyacrylic acid, polyvinyl alcohol, sodium polyacrylate, sodium cholate (and derivatives thereof, chemical drugs with similar chemical structures, and the like), cholic acid, bile acid (and derivatives thereof, chemical drugs with similar chemical structures, and the like), thiobetaine and derivatives thereof, polyvinylpyrrolidone (and derivatives thereof, different molecular weights), polyvinyl caprolactam, polyvinyl acetamide, and the like and derivatives thereof (with an average molecular weight of 8000-700000), polyoxyethylene-based anionic polymer (with an average molecular weight of 10000-120000), sodium dodecyl benzene sulfonate, and long-chain alkane octadecanol.

8. The method for preparing easily dispersible activated nanocarbon powder according to claim 1, wherein: the stabilizer is one or more of DNA, RNA, cellulose and derivatives thereof, sodium carboxymethyl cellulose and the like.

9. The method for preparing easily dispersible activated nanocarbon powder according to claim 7, wherein: the sodium cholate includes, but is not limited to, sodium glycocholate, sodium glycodeoxycholate, sodium chenodeoxycholate, sodium taurocholate, and sodium deoxycholate.

10. The method for preparing easily dispersible activated nanocarbon powder according to claim 3, wherein: the solvent is at least one of water, N-methyl pyrrolidone (NMP), ethanol, isopropanol, toluene, benzene, ethyl acetate, butyl acetate, butanone, N-butanol, cyclohexane and methyl ethyl ketone.

Technical Field

The invention belongs to nano carbon dispersion slurry applied to polar, weak polar and non-polar solvents, and particularly relates to a surface modification technology of easily dispersed active nano carbon powder and a preparation method thereof.

Background

The fine nano carbon powder is extremely difficult to disperse, and the produced fine nano carbon powder can only be dispersed in solvent forming slurry for sale and transportation in the prior art, so that the fine nano carbon powder conductive slurry obtained in the mode has low carbon nano tube content, and the solvent content exceeds 90%, thereby greatly limiting the application range and the field of the fine nano carbon powder. Solvents in amounts exceeding 90% also cause difficulties in transportation and increased costs for customer use. The traditional dispersed nano carbon powder is usually in a medium with water as a solvent, and is similar to the preparation result disclosed in the patent CN 111247095-A. The Chinese patent application CN 1117400-A provides a method for improving the concentration of a monodisperse carbon nano tube dispersion liquid, compared with the traditional method, the concentration of the dispersion liquid can only reach 1mg/mL, the method can only improve to 1.5-4mg/mL, and the method is still lower than the carbon nano tube active powder. The invention of Chinese patent application CN110591787-A relates to application of a solvent-free carbon nanotube fluid, wherein the solvent-free carbon nanotube fluid is obtained by taking a carbon nanotube as a nano inner core and performing ultrasonic treatment and silane coupling agent and amino-terminated block copolymer grafting, but the dispersed fluid is substantially amino-terminated block copolymer dispersed liquid and has difficulty in transportation.

Disclosure of Invention

Aiming at the defects in the prior art, the technical problem to be solved by the invention is to provide the easily-dispersible activated nano carbon powder, so that the nano carbon powder and the solvent are separately transported, and when the activated nano carbon powder is required to be used, the easily-dispersible activated nano carbon powder and the solvent are mixed to prepare the conductive slurry, so that the transportation and storage costs of the conductive slurry are reduced.

In order to realize the aims of dispersion and transportation storage, the invention adopts an active nano carbon powder strategy:

s1, mixing nano-carbon and a dispersing agent in a ball milling and nano-grinding mode, wherein the nano-carbon contains 50-95% by mass, the dispersing agent contains 5-50% by mass, and 0-5% of a stabilizing agent is added to obtain slurry containing micro nano-carbon;

s2, drying and secondarily grinding the fine nano-carbon slurry prepared in the step (1) to obtain solid activated carbon powder, wherein the activated carbon powder has better dispersibility in a strong polar solvent;

s3, if active carbon powder which can be well dispersed in a nonpolar or low-polarity solvent is to be obtained, mixing the solid active carbon powder and dopamine in the step (2) to react to generate a polydopamine coating, fully washing and drying to obtain the polydopamine coating with reactivity, wherein the polydopamine coating comprises 5-50% of polydopamine by mass, and the actual content of the nano carbon powder is higher (60-95%) due to partial loss generated in the washing process of the polydopamine;

s4, in order to increase the oil solubility of the active nano carbon powder prepared in the steps (1, 2 and 3), carrying out graft modification on the surface of polydopamine by adopting a sulfydryl or amino chain hydrocarbon compound containing 2-18 carbon atoms to obtain active nano carbon dispersion slurry;

and S5, drying the active nano carbon slurry prepared in the steps (3 and 4).

Further, the active nano carbon slurry comprises 80-99% by mass of nano carbon, 0.5-10% by mass of a dispersing agent and 0.5-10% by mass of nano carbon.

Further, the nanocarbon comprises: the carbon nano-tube material is one or a mixture of a plurality of single-wall carbon nano-tubes (SWCNT), double-wall carbon nano-tubes (DWCNT), multi-wall carbon nano-tubes (MWCNT), Graphite (GR), fullerene (C60), Graphene (Graphene) or carbon black material (CB).

Further, the dispersing agent includes, but is not limited to, one or more of Disponer 983, FA 196, FX 9086, polyacrylate, polyacrylamide, polyacrylic acid, polyvinyl alcohol, sodium polyacrylate, sodium cholate (and derivatives thereof, chemical chemicals having similar chemical structures, etc.), cholic acid, bile acid (and derivatives thereof, chemical chemicals having similar chemical structures, etc.), thiobetaine and derivatives thereof, polyvinylpyrrolidone (and derivatives thereof, different molecular weights), polyvinyl caprolactam, polyvinyl acetamide, etc. and derivatives thereof (average molecular weight 8000-700000), polyoxyethylene-based anionic polymer (average molecular weight 10000-120000), sodium dodecylbenzenesulfonate, and long-chain alkane octadecanol.

Further, the stabilizer is one or more of DNA, RNA, cellulose and derivatives thereof, and sodium carboxymethyl cellulose.

Further, the sodium cholate includes, but is not limited to, sodium glycocholate, sodium glycodeoxycholate, sodium chenodeoxycholate, sodium taurocholate, and sodium deoxycholate.

Further, the solvent is at least one of water, N-methyl pyrrolidone (NMP), ethanol, isopropanol, toluene, benzene, ethyl acetate, butyl acetate, butanone, N-butanol, cyclohexane and methyl ethyl ketone.

The invention has the beneficial effects that: the active nano carbon powder prepared by the preparation method has good effect of being dispersed in the solvent again, so that the active nano carbon powder can be stored, transported and sold in a solid carbon powder state, and compared with the traditional method that a large amount of liquid solvent is needed for storage and transportation, the active nano carbon powder has lower storage and transportation cost and better safety performance.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the invention without limiting the invention.

FIG. 1 is a schematic flow chart of an embodiment;

FIG. 2CNT-PDA-NDM-8, (A) ball milling treatment for 2 days, (B) cell disruption after removal for 10min, (C) supernatant after centrifugation at 12000 rpm;

FIG. 3 is an infrared spectrum of polydopamine modified carbon nanotubes;

FIG. 4 SEM image of re-dispersion of activated carbon nanotubes in ethyl acetate;

FIG. 5 SEM image of re-dispersion of activated carbon nanotubes in n-butanol;

FIG. 6 SEM image of re-dispersion of activated carbon nanotubes in NMP;

Detailed Description

In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in sequences other than those illustrated or described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

Example one

First, prepare 60 or 100mL Tris solution with concentration of 10 mmol/L: first 72.6 or 121mL of deionized water are dissolved in 60 or 100mL of deionized water, respectively, and the pH is measured, in this case pH 10, and then 1mol/L hydrochloric acid is added dropwise to adjust the pH to about 8.5. And simultaneously or step-by-step adding CNT and dopamine into a Tris solution, carrying out ultrasonic treatment for 5-10min by using a cell crusher, and then carrying out magnetic stirring for 2-24 h at room temperature to carry out a dopamine coating experiment. Then, after centrifugation at 4000rpm for 5min, the supernatant was decanted, and the reaction product was washed in a suction filtration, and the washed reaction product was retained. And then, carrying out a grafting experiment, namely adding 100mL of deionized water into a beaker, adjusting the pH to be more than 12 by using a 2M NaOH solution, adding a cleaned CNT-PDA product, carrying out ultrasonic treatment on the CNT-PDA product for 10min by using a cell crusher, adding dodecyl mercaptan (NDM), wherein the dodecyl mercaptan (NDM) is an oil-soluble substance and floats on the surface of water when being added, and then carrying out a magnetic stirring reaction for more than 10h to obtain a product grafted with the dodecyl mercaptan (NDM), wherein the washed and dried activated carbon nanotube powder has oil solubility and is named as CNT-PDA-NDM-8, and the carbon nanotube powder has activated powder which is easily redispersed in a medium-low polarity solvent.

And (3) testing the dispersibility: as shown in fig. 2, the solvent was ethyl acetate, the modified carbon nanotube powder was pre-dispersed in the ball mill for 2 days, and after being taken out, the left group was not further processed, while the right group was crushed for 10min at 20% power using a cell crusher, and set to a 2s on and 2s off mode. The two groups of products are subjected to centrifugal treatment and are compared, and it can be found that the treated modified carbon nanotube powder has better stability in an ethyl acetate solvent, and the modified carbon nanotube powder still maintains higher concentration after being centrifuged for 5min at a centrifugal rotation speed of 12000 rpm.

Referring to FIG. 3, which is an infrared spectrum of an active powder of polydopamine modified carbon nanotube, two distinct hydroxyl peaks are shown at about 3400cm-1 and 1700cm-1, corresponding to more phenolic hydroxyl groups in polydopamine, two peaks near 2900cm-1 and 2750cm-1 corresponding to C-H bonds, and two peaks near 1400cm-1 and 1300cm-1 corresponding to S ═ O bonds, and the appearance of these peaks indicates that dodecanethiol has been successfully grafted to the surface of the polydopamine coating layer.

Example two

Adding activated carbon nanotube powder into ethyl acetate, performing ultrasonic treatment for 10min by using a cell crusher to obtain slurry with the activated carbon nanotube powder content of 1 wt%, performing suction filtration on the slurry, and performing Scanning Electron Microscope (SEM) observation on the obtained film as shown in figure 4.

Adding activated carbon nanotube powder into n-butanol, performing ultrasonic treatment for 10min by using a cell crusher to obtain slurry with the activated carbon nanotube powder content of 1 wt%, performing suction filtration on the slurry, and performing Scanning Electron Microscope (SEM) observation on the obtained film as shown in figure 5.

Adding activated carbon nanotube powder into NMP, performing ultrasonic treatment for 10min by using a cell crusher to obtain slurry with the activated carbon nanotube powder content of 1 wt%, performing suction filtration on the slurry, and performing scanning electron microscope SEM observation on the obtained film as shown in figure 6.

EXAMPLE III

The method can be expanded to the whole carbon powder system by using a similar method, and due to the existence of dopamine benzene rings, the dopamine benzene rings can easily form pi-pi interaction with the carbon material, so that a coating layer can be formed on the surface of the carbon material more uniformly. Taking 1g of micro nano carbon comprising one or a mixture of a single-wall carbon nanotube (SWCNT), a double-wall carbon nanotube (DWCNT), a multi-wall carbon nanotube (MWCNT), Graphite (GR), fullerene (C60), Graphene (Graphene) or carbon black material (CB) in a 250mL beaker, adding 100mL of deionized water or ethanol, adjusting the pH value to about 8.5, adding 0.5-1g of dopamine hydrochloride powder, performing ultrasonic treatment for 10min, and performing magnetic stirring self-polymerization reaction for 24h in the air. And (3) obtaining the fine nano-carbon coated with the polydopamine, performing suction filtration and washing for 3-5 times, washing away residual uncoated polydopamine small particles and trihydroxymethyl aminomethane, and freeze-drying for later use, wherein the nano-carbon is respectively named as nano-carbon (SWCNT, DWCNT … …) -PDA. nanocarbon-PDA was further dispersed in 100mL Tris buffer (10mM, pH 8.5). 1g of polyPEGMA was then added to the mixture and reacted at room temperature overnight. These synthesized CNT-PDA-PEGMA composites were freed of unreacted polymer by repeated centrifugation and washing. The obtained active fine nano carbon powder has better dispersibility and biocompatibility of the weak/nonpolar organic solvent.

It will be appreciated by those of ordinary skill in the art that the embodiments described herein are intended to assist the reader in understanding the principles of the invention and are to be construed as being without limitation to such specifically recited embodiments and examples. Those skilled in the art can make various other specific changes and combinations based on the teachings of the present invention without departing from the spirit of the invention, and these changes and combinations are within the scope of the invention.