Carbon nanotube dispersion apparatus, applications, and methods

Abstract

The application discloses a carbon nanotube dispersing device, application and method, and belongs to the technical field of carbon nanotube dispersion. The dispersing device comprises a transfer tank and an ultrasonic assembly. The bottom of the transfer tank is connected with the ultrasonic assembly through a circulating pump. The top of the transfer tank is connected with the ultrasonic assembly through a de-ironing device. A vacuum pump is also installed on the top of the transfer tank. The application also discloses the application of the dispersing device in carbon nanotube dispersion, and discloses a method for dispersing carbon nanotubes by using the device. The method can partially replace the currently used methods, such as sand milling. The method is a physical process for dispersing carbon nanotube slurry, and the process is pollution-free and controllable. The dispersed carbon nanotube slurry has the advantages of good consistency, high quality, few defects and the like, and can be mass-produced and industrialized.

Description

Technical Field

[0001] This invention belongs to the field of dispersion device technology, and particularly relates to a carbon nanotube dispersion device, its application and method. Background Technology

[0002] Since Iijima's discovery of carbon nanotubes in 1991, their enormous specific surface area, chemical stability, unique electronic structure, nanoscale hollow cavities, and excellent adsorption properties have led to their significant applications in mechanics, thermodynamics, optics, electronics, catalysis, and sensors. However, as a highly polarized, smooth-surfaced inorganic polymer, carbon nanotubes are subject to strong van der Waals forces, and their large specific surface area and high aspect ratio make them prone to entanglement and aggregation into bundles. Furthermore, the lack of active groups in carbon nanotubes makes them poorly soluble in common organic solvents and water, significantly limiting their applications. Therefore, achieving high dispersion of carbon nanotubes has become a key challenge in advancing their applications.

[0003] Currently, the main methods for mechanical dispersion of carbon nanotubes include sand milling and stirring, high-energy ball milling, and ultrasonic treatment. Among these, sand milling, a relatively mature method, has unique advantages: ① the particle size is smaller and the particle size distribution is more uniform after grinding; ② it has high energy utilization and high dispersion efficiency; ③ the sand mill has a simple structure and is easy to operate. However, its disadvantages are also significant: ① the aspect ratio of the carbon nanotubes is significantly reduced after processing; ② the grinding media is easily worn away during the dispersion process, generating debris that contaminates the carbon nanotube sample and cannot be removed; ③ sand milling often covalently grafts oxygen- and nitrogen-containing polar groups onto the surface of carbon nanotubes, increasing defects and affecting the inherent properties of the carbon nanotubes. Furthermore, in applications using ultrasonic dispersion, ultrasound is only applied to the carbon nanotube slurry without considering the wetting or mixing degree of the liquid carbon nanotubes, severely limiting the effectiveness of the ultrasound. Therefore, none of the above methods can effectively solve the problem of carbon nanotube aggregation and entanglement.

[0004] Therefore, how to disperse carbon nanotubes while preserving their length is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention proposes a carbon nanotube dispersion device, application, and method that deagglomerates entangled carbon nanotubes, preserving as much of the original one-dimensional length of the carbon nanotubes as possible, thereby preparing a uniform and dispersed carbon nanotube slurry.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A carbon nanotube dispersion device includes: a transfer tank and an ultrasonic component;

[0008] The bottom of the transfer tank is connected to the ultrasonic component via a circulation pump;

[0009] The top of the transfer tank is connected to the ultrasonic component via a magnetic separator;

[0010] A vacuum pump is also installed on the top of the transfer tank.

[0011] Beneficial effects: The present invention proposes a method to disperse entangled and agglomerated carbon nanotubes by utilizing the cavitation effect of ultrasound in liquids, combined with a circulation system, vacuum degassing, iron removal, and additional pressure, while preserving the original one-dimensional length as much as possible. This method can be applied to large-scale production.

[0012] Preferably, the transfer tanks include a first transfer tank and a second transfer tank installed in parallel;

[0013] The first and second transfer tanks are respectively connected to the vacuum pump via valve one and valve two;

[0014] The first and second transfer tanks are respectively connected to the iron separator by valve three and valve four;

[0015] The first and second transfer tanks are respectively connected to the circulating pump via valve five and valve six;

[0016] A discharge valve is also included between the first transfer tank and the fifth valve.

[0017] More preferably, all valves are pneumatic valves.

[0018] Beneficial effects: Since carbon nanotubes have a certain viscosity during dispersion, the pneumatic valve used in this invention can be quickly opened and closed, and the pneumatic valve can be tightly closed with very small torque; in addition, many of the solvents used to disperse carbon nanotubes in this invention are flammable and explosive chemical reagents, and the use of pneumatic valves is safer and more reliable.

[0019] Preferably, the circulating pump and the ultrasonic component further include a pressure gauge and a heat sink connected in series.

[0020] Among them, the circulating pump provides power for circulation and can be a self-priming pump, centrifugal pump, rotary pump, diaphragm pump, screw pump, etc.

[0021] The radiator is a tubular radiator.

[0022] Beneficial effects: Due to the viscosity of the carbon nanotube slurry during processing, the tubular radiator used in this invention is less prone to clogging and is easy to clean. Most of the energy generated during the ultrasonic process is converted into heat, causing the carbon nanotube slurry temperature to rise. The tubular radiator, along with the water-cooled jacket on the outer wall of the transfer tank, works together to dissipate heat and control the temperature of the carbon nanotube slurry.

[0023] Preferably, the iron remover and the ultrasonic component further include a valve and a thermometer connected in series;

[0024] The iron separator is composed of strong magnets with a strength of 10,000-50,000 GS.

[0025] More preferably, the strength of the iron remover is 12000GS.

[0026] Preferably, the ultrasonic component includes an ultrasonic vessel, an ultrasonic power supply, an ultrasonic transducer, and an ultrasonic radiating end.

[0027] The ultrasonic radiating end is installed inside the ultrasonic vessel, and the ultrasonic radiating end is connected to the ultrasonic power supply through the ultrasonic transducer.

[0028] Beneficial effects: First, the ultrasonic power supply in this invention can convert electrical energy into a high-frequency AC signal component that matches the ultrasonic transducer. The signal frequency is 20-100kHz, effectively transmitting ultrasonic electrical energy to the ultrasonic transducer and driving it. Second, the ultrasonic transducer in this invention can convert the high-frequency oscillating electrical signal from the ultrasonic power supply into longitudinal mechanical vibration (i.e., ultrasound) and then transmit it, that is, transmit the longitudinal wave to the ultrasonic radiating end. The transducer is cylindrical in shape, with a structure similar to that of existing piezoelectric ceramic transducers. Furthermore, the acoustic radiating head in this invention can transmit the ultrasonic waves from the transducer to the liquid medium through the radiating surface. The ultrasonic radiating end is inserted into the ultrasonic vessel and directly contacts the carbon nanotube slurry, allowing for more efficient energy transfer to the carbon nanotubes themselves.

[0029] Preferably, the transfer tank includes a feeding port, a stirring paddle, and a water-cooled jacket;

[0030] The water-cooled jacket is wrapped around the outer wall of the transfer tank.

[0031] In this invention, the water-cooling jacket does not come into contact with the carbon nanotube slurry, and even if fog forms, it is on the outer wall of the transfer tank.

[0032] Application of a carbon nanotube dispersion device in carbon nanotube dispersion.

[0033] A method for dispersing carbon nanotubes, using the aforementioned carbon nanotube dispersion apparatus, specifically includes the following steps:

[0034] (1) Add equal amounts of carbon nanotube slurry to the first and second transfer tanks respectively, turn on the agitator, and turn on the vacuum pump and valves to premix and degas. After the premixing and degassing are completed, keep the vacuum pump in the normally open state, close valve one, open valve three and valve five, start the circulation pump, and control the pressure between the circulation pump and valve seven by adjusting valve seven. The carbon nanotube slurry passes through the circulation pump, pressure gauge, radiator, ultrasonic component, thermometer, valve seven, iron remover and valve three in sequence, and finally returns to the first transfer tank. At this time, turn on the ultrasonic power supply to ultrasonically disperse the carbon nanotubes.

[0035] (2) After ultrasonic dispersion, close valves 2, 3 and 5, and open valves 1, 4 and 6. Use ultrasonic dispersion to disperse the carbon nanotube slurry in the second transfer tank, and mix, cool and degas the carbon nanotubes in the first transfer tank.

[0036] (3) The carbon nanotube slurry in the first and second transfer tanks is alternately dispersed using the dispersion methods in steps (1) and (2), and then the discharge valve is opened to discharge the uniformly dispersed carbon nanotube slurry. The alternating dispersion method used in this invention can greatly improve the dispersion efficiency.

[0037] Preferably, the premixing and degassing time in step (1) is 30 min;

[0038] The pressure between the circulating pump and valve seven is 0.5 MPa;

[0039] The flow rate of the carbon nanotube slurry is 0.5-5m. 3 / h, more preferably 1m 3 / h;

[0040] The temperature of the carbon nanotube slurry during the ultrasonic dispersion process is 50±5℃.

[0041] The ultrasonic dispersion time is 15 min;

[0042] The ultrasonic power supplies are all 3000W, and the frequencies are three 20kHz and one 40kHz ultrasonic reactors connected in series.

[0043] The ultrasonic radiating end adopts an insertable cylindrical ultrasonic radiating head made of magnetic material.

[0044] More preferably, depending on actual needs, the ultrasonic waves participating in the cyclic process can be one or more sets working simultaneously, that is, any combination of different working frequencies, different types of radiating ends, and different vibration modes (continuous vibration or intermittent vibration).

[0045] Beneficial effects: This invention selects an insertable ultrasonic radiating end. During the operation, metal may fall off the radiating end itself, which can be removed by the iron remover at the rear end to avoid contamination.

[0046] Preferably, the alternating dispersion time in step (3) is 240 min.

[0047] Beneficial effects: Under the above dispersion time, the length of carbon nanotubes can be guaranteed not to be damaged, and a uniformly dispersed carbon nanotube slurry can be obtained.

[0048] Compared with existing technologies, this invention discloses a carbon nanotube dispersion device, its application, and a method. First, this invention introduces additional pressure within the ultrasonic reactor, which is beneficial for the ultrasonic dispersion of carbon nanotubes. Second, it employs two sets of transfer tanks: one set participates in ultrasonic cyclic dispersion, while the other set undergoes vacuum degassing. This not only reduces the ultrasonic dispersion time but also produces a more uniform and consistent carbon nanotube slurry. The method employed in this invention can partially replace currently used methods, such as sand milling. This method disperses the carbon nanotube slurry through a physical process, which is pollution-free, process-controllable, and produces a dispersed carbon nanotube slurry with advantages such as good consistency, high quality, and few defects. Furthermore, it can be mass-produced industrially. Attached Figure Description

[0049] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0050] Figure 1 This is a schematic diagram of the carbon nanotube dispersion device in Embodiment 1 of the present invention;

[0051] Figure 2 This is a SEM image of the carbon nanotubes before dispersion in Example 2 of the present invention;

[0052] Figure 3 This is a scanning electron microscope (SEM) image of the carbon nanotube slurry obtained in Example 2 of the present invention. Detailed Implementation

[0053] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0054] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0055] Example 1

[0056] A carbon nanotube dispersion device includes: a transfer tank and an ultrasonic component 6;

[0057] The bottom of the transfer tank is connected to the ultrasonic component 6 via a circulation pump 3;

[0058] The top of the transfer tank is connected to the ultrasonic component 6 via a magnetic separator 9.

[0059] A vacuum pump 10 is also installed on the top of the transfer tank.

[0060] Furthermore, the transfer tanks include a first transfer tank 1 and a second transfer tank 2 installed in parallel;

[0061] The first transfer tank 1 and the second transfer tank 2 are respectively connected to the vacuum pump 10 by valve 106 and valve 206;

[0062] The first transfer tank 1 and the second transfer tank 2 are respectively connected to the iron separator 9 by valve 3 105 and valve 4 205;

[0063] The first transfer tank 1 and the second transfer tank 2 are respectively connected to the circulating pump 3 by valve 5 104 and valve 6 204;

[0064] The first transfer tank 1 and valve 5 104 also include a discharge valve 11.

[0065] Furthermore, the first transfer tank 1 includes a feeding port 103, an agitator 101, and a water-cooling jacket 102;

[0066] Water-cooled jacket 102 is wrapped around the outer wall of the first transfer tank 1;

[0067] The second transfer tank 2 includes a second feeding port 203, a second stirring paddle 201, and a second water-cooled jacket 202;

[0068] Water-cooled jacket 202 is wrapped around the outer wall of the second transfer tank 2;

[0069] Furthermore, a pressure gauge 4 and a tubular radiator 5 are connected in series between the circulating pump 3 and the ultrasonic component 6.

[0070] Furthermore, the iron remover 9 and the ultrasonic component 6 also include a valve 7 8 and a thermometer 7 connected in series.

[0071] Furthermore, the ultrasonic component 6 includes an ultrasonic vessel 601, an ultrasonic power supply 602, an ultrasonic transducer 603, and an ultrasonic radiating end 604.

[0072] The ultrasonic radiating end 604 is installed inside the ultrasonic vessel 601, and the ultrasonic radiating end 604 is connected to the ultrasonic power supply 602 through the ultrasonic transducer 603.

[0073] Example 2

[0074] A carbon nanotube dispersion method, using the carbon nanotube dispersion device of Example 1, specifically includes the following steps:

[0075] (1) Add equal amounts of carbon nanotube slurry to the first transfer tank 1 and the second transfer tank 2 respectively. Turn on the agitator, and turn on the vacuum pump 10, valve 106 and valve 206 for premixing and degassing for 30 minutes. After the premixing and degassing is completed, keep the vacuum pump 10 in the normally open state, close valve 106, open valve 3 105 and valve 5 104, and start the circulation pump 3. Adjust the pressure between the circulation pump 3 and valve 7 8 to 0.5 MPa by adjusting valve 7 8. The carbon nanotube slurry passes through the circulation pump 3, pressure gauge 4, tubular radiator 5, ultrasonic component 6, thermometer 7, valve 7 8, iron separator 9 and valve 3 105 in sequence, and finally returns to the first transfer tank 1, ensuring that the flow rate of the carbon nanotube slurry is 1 m. 3 / h, at this time, turn on the ultrasonic power supply 602 to ultrasonically disperse the carbon nanotubes at 50±5℃ for 15min;

[0076] Among them, the ultrasonic power supply 602 has a power of 3000W, and the ultrasonic vessel 601 is connected in series with three 20kHz and one 40kHz frequencies.

[0077] The ultrasonic radiating end 604 adopts an insertable round bar structure ultrasonic radiating head, which is made of magnetic material.

[0078] (2) After ultrasonic dispersion, close valve 206, valve 3105 and valve 5104, open valve 1106, valve 4205 and valve 6204, ultrasonically disperse the carbon nanotube slurry in the second transfer tank 2, and uniformly mix, cool and degas the carbon nanotubes in the first transfer tank 1.

[0079] (3) The carbon nanotube slurry in the first transfer tank 1 and the second transfer tank 2 is alternately dispersed for 240 minutes using the dispersion methods in steps (1) and (2), and then the discharge valve 11 is opened to discharge the uniformly dispersed carbon nanotube slurry.

[0080] The changes in carbon nanotubes before and after dispersion were observed under a scanning electron microscope. Figure 1 The image shows the microstructure of carbon nanotube raw materials under SEM scanning. It can be seen that the carbon nanotubes are massively aggregated, while from... Figure 2The SEM scan image after dispersion shows that the carbon nanotubes are completely and uniformly dispersed, with no obvious agglomeration, and the average length does not change significantly. This indicates that the dispersion device and method in this invention can disperse the carbon nanotubes uniformly without damaging their length, thus obtaining a uniform carbon nanotube slurry.

[0081] The above are merely preferred embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for dispersing carbon nanotubes, characterized in that, The carbon nanotube dispersion device used includes: a transfer tank and an ultrasonic component; The bottom of the transfer tank is connected to the ultrasonic component via a circulation pump; The top of the transfer tank is connected to the ultrasonic component via a magnetic separator; A vacuum pump is also installed on the top of the transfer tank; The ultrasonic component includes an ultrasonic vessel, an ultrasonic power supply, an ultrasonic transducer, and an ultrasonic radiating end. The ultrasonic radiating end is installed inside the ultrasonic vessel, and the ultrasonic radiating end is connected to the ultrasonic power supply through the ultrasonic transducer. The transfer tanks include a first transfer tank and a second transfer tank installed in parallel; The first and second transfer tanks are respectively connected to the vacuum pump via valve one and valve two; The first and second transfer tanks are respectively connected to the iron separator by valve three and valve four; The first and second transfer tanks are respectively connected to the circulating pump via valve five and valve six; A discharge valve is also included between the first transfer tank and the fifth valve; The circulating pump and the ultrasonic component also include a pressure gauge and a radiator connected in series. The iron remover and the ultrasonic component also include a valve seven and a thermometer connected in series. The transfer tank includes a stirring paddle; The carbon nanotube dispersion method specifically includes the following steps: (1) Add equal amounts of carbon nanotube slurry to the first and second transfer tanks respectively, turn on the agitator, and turn on the vacuum pump and valves one and two for premixing and degassing. After the process is completed, keep the vacuum pump in the normally open state, close valve one, open valves three and five, start the circulation pump, and control the pressure between the circulation pump and valve seven by adjusting valve seven. The carbon nanotube slurry passes through the circulation pump, pressure gauge, radiator, ultrasonic component, thermometer, valve seven, iron remover and valve three in sequence, and finally returns to the first transfer tank. At this time, turn on the ultrasonic power supply to ultrasonically disperse the carbon nanotubes. (2) After ultrasonic dispersion, close valves 2, 3 and 5, and open valves 1, 4 and 6. Use ultrasonic dispersion to disperse the carbon nanotube slurry in the second transfer tank, and mix, cool and degas the carbon nanotubes in the first transfer tank. (3) The carbon nanotube slurry in the first transfer tank and the second transfer tank is alternately dispersed using the dispersion methods in steps (1) and (2), and then the discharge valve is opened to discharge the uniformly dispersed carbon nanotube slurry.

2. The carbon nanotube dispersion method according to claim 1, characterized in that, The premixing and degassing time in step (1) is 30 min; The pressure between the circulating pump and valve seven is 0.5 MPa; The flow rate of the carbon nanotube slurry is 0.5-5m. 3 / h; The temperature of the carbon nanotube slurry during the ultrasonic dispersion process is 50±5℃. The ultrasonic dispersion time is 15 min; The ultrasonic power supplies are all 3000W, and the frequencies are three 20kHz and one 40kHz ultrasonic reactors connected in series. The ultrasonic radiating end adopts an insertable cylindrical ultrasonic radiating head made of magnetic material.

3. The carbon nanotube dispersion method according to claim 1, characterized in that, The alternating dispersion time in step (3) is 240 min.

4. The carbon nanotube dispersion method according to claim 1, characterized in that, The iron separator is composed of strong magnets with a strength of 10,000-50,000 GS.

5. The carbon nanotube dispersion method according to claim 1, characterized in that, The transfer tank includes a feeding port and a water-cooled jacket; The water-cooled jacket is wrapped around the outer wall of the transfer tank.

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