Device and method for on-line continuous growth of carbon nanotubes on fiber surface

Abstract

The invention relates to a device and a method for continuously growing carbon nanotubes on fiber surfaces on line. The device comprises a reaction chamber, wherein the reaction chamber comprises a reaction gas inlet pipe and a tail gas pipe; the wire feeding pipe is arranged on the wall of the reaction chamber; a first protective gas inlet pipe is arranged on the pipe wall of the wire inlet pipe; the wire outlet pipe is arranged on the wall of the reaction chamber; and a second protective gas inlet pipe is arranged on the pipe wall of the wire outlet pipe. The technical problem to be solved is how to provide a device, by using the device, fiber yarns can be continuously fed into the device on line, the exchange between the atmosphere in the device and the outside is avoided, the stability of the atmosphere in the device is not influenced, and the carbon nanotubes can be grown on the surfaces of the fibers by adopting a chemical vapor deposition method. And continuous large-scale production is realized.

Description

Technical Field

[0001] The invention belongs to the field of carbon nanotubes, and in particular relates to a device and method for online continuous growth of carbon nanotubes on fiber surfaces. Background Art

[0002] In recent years, growing carbon nanotubes on the fiber surface is one of the research directions for designing new structural and functional integrated materials. Through this method, important breakthroughs have been made in improving the interface strength of composite materials, preparing flexible electromagnetic shielding materials, and reducing the weight of aircraft. Chemical deposition method is currently the most widely used and promising method for preparing carbon nanotubes in the industry, because the temperature required for growing carbon nanotubes on the fiber surface is low and the relevant parameters are easy to control, which makes the fine structure of the produced carbon nanotubes controllable and the output carbon nanotubes high in purity.

[0003] However, the typical chemical vapor deposition device used in the traditional chemical vapor deposition method includes a high-temperature heating furnace, a quartz tube, a carrier boat placed inside the quartz tube, and a gas path system matched therewith. Generally speaking, the traditional device used for growing carbon nanotubes on the fiber surface by chemical vapor deposition is closed during operation, and the entire system is isolated from the external gas, and it is impossible to continuously put fibers into the device online to achieve continuous production; further, the traditional chemical deposition device usually has a small inner diameter. This is because when the inner diameter is too large, the reaction area inside the device is not concentrated enough, the reaction environment is not uniform enough, and the quality of the carbon nanotubes is unstable. Therefore, the production volume of growing carbon nanotubes on the fiber surface using the traditional chemical deposition device is limited, and it is difficult to achieve large-scale production, which limits the application field and industrial production of carbon nanotube-grown fiber composite materials. Summary of the invention

[0004] The main purpose of the present invention is to provide an apparatus and method for online continuous growth of carbon nanotubes on the fiber surface. The technical problem to be solved is how to provide a device that can realize online continuous transmission of fiber filaments in the device, avoid the exchange of the internal atmosphere of the device with the outside world, and the internal atmosphere of the device has good stability, so that it can adopt chemical vapor deposition method to grow carbon nanotubes on the fiber surface and realize continuous large-scale production.

[0005] The purpose of the present invention and the technical problem to be solved are achieved by adopting the following technical solutions. According to the present invention, a device for growing carbon nanotubes on the surface of a fiber online and continuously comprises a reaction chamber, the reaction chamber comprises a reaction gas inlet pipe and an exhaust pipe, and further comprises:

[0006] A wire inlet pipe is arranged on the wall of the reaction chamber; a first protective gas inlet pipe is arranged on the wall of the wire inlet pipe;

[0007] The wire outlet pipe is arranged on the wall of the reaction chamber; and a second protective gas inlet pipe is arranged on the wall of the wire outlet pipe.

[0008] The purpose of the present invention and the solution to its technical problems can be further achieved by adopting the following technical measures.

[0009] Preferably, in the aforementioned device, the inner diameters of the wire inlet and outlet tubes are circular and have an inner diameter of D 1 The first protective gas inlet pipe and the second protective gas inlet pipe have a circular inner diameter and an inner diameter of D 2 , D 1 :D 2 It is 0.7~1.4:1.

[0010] Preferably, the aforementioned device further comprises a heating device, wherein the heating device forms a heating area inside the reaction chamber, and the reaction gas inlet pipe and the wire inlet pipe extend to the heating area inside the reaction chamber.

[0011] Preferably, in the aforementioned device, the reaction gas inlet pipe and the wire inlet pipe are arranged in parallel on the same wall of the reaction chamber, and the extension ports of the reaction gas inlet pipe and the wire inlet pipe inside the reaction chamber are flush.

[0012] Preferably, in the aforementioned device, the side walls of the reaction chamber are respectively perpendicular to the top wall and the bottom wall; and the heating system is arranged above the top wall and / or below the bottom wall.

[0013] The purpose of the present invention and the technical problems solved by the present invention are also achieved by the following technical solutions. According to a method for online continuous growth of carbon nanotubes on the surface of fiber filaments proposed by the present invention, the fiber filaments can enter the reaction system online through a fiber inlet channel to react with the reaction gas, and the fiber filaments can also leave the reaction system online through a fiber outlet channel to terminate the reaction with the reaction gas; the fiber inlet channel and the fiber outlet channel are protected by an inert gas.

[0014] The purpose of the present invention and the solution to its technical problems can be further achieved by adopting the following technical measures.

[0015] Preferably, in the aforementioned method, the inert gas is a mixture of one or more of nitrogen, argon and helium; the reaction gas includes a catalyst gas precursor, a reducing gas and a carbon source gas; the catalyst precursor is a mixture of one or more metal elements selected from the group consisting of iron, cobalt, nickel and copper.

[0016] Preferably, the aforementioned method comprises the following steps:

[0017] S1: the fiber filaments enter the reaction system from the fiber inlet channel and come out from the fiber outlet channel;

[0018] S2 uses inert gas to protect the wire inlet and outlet channels and exhaust the air from the reaction system;

[0019] S3: heating the reaction system to a preset temperature;

[0020] S4: The reaction gas is introduced and the fiber filaments begin to be transmitted at a predetermined speed.

[0021] Preferably, in the above method, the catalyst solution is atomized to form a catalyst gas precursor, the catalyst solution concentration is 0.1 to 0.5 mol / L, and the catalyst solution is atomized at a rate of 0.25 to 0.42 μL / min. -1 The speed diffuses into each liter of the reaction system; the flow rates of the reducing gas and the carbon source gas introduced into each liter of the reaction system are 15-50 sccm and 4-45 sccm respectively; the flow rate of the inert gas introduced into each liter of the reaction system is 40-170 sccm.

[0022] Preferably, in the aforementioned method, the transmission speed of the fiber filaments in the reaction system is 1 to 10 cm / min; and the preset temperature is 500 to 850°C.

[0023] By means of the above technical solution, the device and method for online continuous growth of carbon nanotubes on the fiber surface proposed by the present invention have at least the following advantages:

[0024] 1. The present invention provides an online device and method for continuously growing carbon nanotubes on the surface of fibers. By arranging a wire inlet tube and a wire outlet tube in the device, the fiber filaments are transmitted online in the device. By arranging a first protective gas inlet tube and a second protective gas inlet tube on the walls of the wire inlet tube and the wire outlet tube, on the one hand, an inert gas is introduced to isolate the atmosphere inside the device from the outside world, which not only improves the stability of the atmosphere inside the device, but also avoids safety hazards caused by the contact between the internal gas and the external gas. On the other hand, the fiber filaments are protected by the inert gas before reacting with the reaction gas, which realizes the stability of the carbon nanotube growth environment and ensures the growth quality of the carbon nanotubes.

[0025] Further preferably, the inner diameters of the wire inlet and outlet tubes are circular and have an inner diameter of D 1 The first protective gas inlet pipe and the second protective gas inlet pipe have a circular inner diameter and an inner diameter of D 2 , D 1 :D 2 The ratio is 0.7 to 1.4:1. This technical solution makes the amount of gas introduced into the protective gas inlet pipe have little effect on the stability of the atmosphere inside the device, thereby avoiding affecting the quality of carbon nanotubes grown on the fiber surface inside the device.

[0026] 2. The present invention provides a method for online continuous growth of carbon nanotubes on the surface of fiber filaments. The inert gas protects the channel for the fiber filaments to enter or leave the reaction system, so that the internal atmosphere of the reaction system is isolated from the external gas. The atmosphere has good stability, which helps to improve the environmental stability of the growth of carbon nanotubes on the fiber surface. Furthermore, by adjusting the flow rate of the reaction gas and the wire feeding speed, the online continuous growth of carbon nanotubes on the surface of the fiber filament is achieved, and the product quality is good.

[0027] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a schematic diagram of a device for online continuous growth of carbon nanotubes on the surface of fiber filaments according to the present invention;

[0029] Figure 2 Scanning electron microscope image of the glass fiber grown with carbon nanotubes obtained in Example 1;

[0030] Figure 3 Scanning electron microscope image of the glass fiber grown with carbon nanotubes obtained in Example 2;

[0031] Figure 4 Scanning electron microscope image of the glass fiber grown with carbon nanotubes obtained in Example 3;

[0032] Figure 5 Scanning electron microscope image of the glass fiber grown with carbon nanotubes obtained in Comparative Example 1. DETAILED DESCRIPTION

[0033] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following is a device and method for online continuous growth of carbon nanotubes on the fiber surface proposed by the present invention in combination with the accompanying drawings and preferred embodiments. Its specific implementation, structure, characteristics and effects are described in detail as follows.

[0034] The inventors found that the reason why the devices and methods used in the traditional chemical vapor deposition method cannot realize the continuous input of fibers to produce carbon nanotubes is that when the fibers are put into or out of the device, the gas environment in the device will inevitably change, which will affect the growth of carbon nanotubes on the fiber surface inside the device, resulting in poor quality of carbon nanotubes grown on the fiber surface; and when the fibers enter the device, they may react under low temperature and low reaction gas conditions. If they are in direct contact with the reaction gas, the quality stability of carbon nanotubes grown on the fiber surface will be poor. In addition, the inventors also found that the traditional chemical deposition method has low concentration in the reaction zone, and the uniformity of various reaction parameters in the reaction area is poor, resulting in poor uniformity of the reaction environment, and thus poor quality stability of carbon nanotubes.

[0035] Based on the above findings, the applicant has designed an online and continuous device and method for growing carbon nanotubes on the surface of fibers. By improving the traditional chemical vapor deposition device and method, the exchange of the atmosphere inside the device with the atmosphere is avoided, and the fiber filaments are continuously put into the device. Before the fiber filaments enter the device and before entering the reaction zone, the fiber filaments are isolated from the reaction gas by inert gas, and the fiber filaments that have reacted are promptly separated from the reaction zone, so as to achieve continuous large-scale high-quality production without affecting the reaction atmosphere inside the device, so as to ensure the quality stability of the carbon nanotubes grown on the fiber surface. Furthermore, the reaction zone for growing carbon nanotubes on the fiber surface is concentrated and restricted, so that the reaction parameters in the reaction zone are uniform, so as to achieve efficient and stable growth of carbon nanotubes on the fiber surface.

[0036] like Figure 1 As shown, some embodiments of the present invention provide an apparatus for growing carbon nanotubes on a fiber surface online and continuously, comprising:

[0037] The reaction chamber 7 is a chamber for growing carbon nanotubes on the fiber surface. The reaction chamber is a cavity formed by a chemically stable and high temperature resistant material. In some embodiments, the reaction chamber is made of quartz or stainless steel. The shape of the reaction chamber is not specifically limited and any shape is acceptable. The reaction chamber includes a reaction gas inlet pipe 5 and an exhaust pipe 6. The reaction gas enters the reaction chamber through the reaction gas inlet pipe. The wall where the reaction gas inlet pipe is located is adjacent to or on the same wall as the wall where the fiber inlet pipe is located, so that the fiber filaments can react in time after entering the reaction chamber. In some embodiments, the reaction gas inlet pipe is preferably provided with a valve. By opening the valve, the reaction gas can be introduced into the reaction chamber. The exhaust pipe is arranged on the wall away from the reaction gas inlet pipe to discharge the reaction exhaust gas out of the reaction chamber.

[0038] The device also includes a wire inlet pipe 2 and a wire outlet pipe 3. The wire inlet pipe is arranged on the wall of the reaction chamber, and the fiber filaments enter the reaction chamber from the wire inlet pipe. A first protective gas inlet pipe 4a is arranged on the wall of the wire inlet pipe, and the wire inlet pipe is connected to the first protective gas inlet pipe; the wire outlet pipe is arranged on the wall of the reaction chamber, and a second protective gas inlet pipe 4b is arranged on the wall of the wire outlet pipe, and the second protective gas inlet pipe is connected to the wire outlet pipe. In some embodiments, the wire inlet pipe is arranged opposite to the wall where the wire outlet pipe is located. In another embodiment, a fiber filament transmission direction conversion device is also arranged inside the reaction chamber to change the transmission direction of the fiber filaments so that the fiber filaments 1 are transmitted from the same side wall as the wire inlet pipe or from the adjacent wall.

[0039] The device provided by the above scheme is adopted, and inert gas is introduced through the first protective gas inlet pipe and the second protective gas inlet pipe, so that when the fiber filaments enter and leave the reaction chamber, the gas in the reaction chamber is isolated from the external gas, the internal atmosphere of the reaction device is kept stable, and the safety hazards caused by the contact between the reaction gas and the outside world are avoided during the reaction; on the other hand, the position of the protective gas inlet pipe is set so that the fiber filaments are isolated from the reaction gas before the reaction occurs, the stability of the environment for the growth of carbon nanotubes on the fiber surface is improved, and the quality of the carbon nanotubes grown on the fiber surface is guaranteed. Therefore, through the new chemical vapor deposition device provided by the present invention, it is possible to realize the online continuous introduction of fiber filaments into the reaction chamber during the reaction process, and the fiber filaments that have completed the reaction are separated from the reaction chamber without affecting the atmosphere inside the reaction chamber, so that the continuous high-quality production of carbon nanotubes grown on the fiber surface by chemical deposition can be realized, and then the large-scale production of carbon nanotubes grown on the fiber surface can be realized.

[0040] In order to better ensure that the atmosphere inside the reaction chamber remains constant within a certain range, the inner diameters of the inlet and outlet wire tubes are circular and the inner diameters are D 1 The first protective gas inlet pipe and the second protective gas inlet pipe have a circular inner diameter and an inner diameter of D 2 , D 1 :D 2 is 0.7 to 1.4:1, and more preferably, D 1 :D 2The ratio of the inner diameters of the inlet and outlet wire tubes to the inner diameters of the first and second protective gas inlet pipes is strictly limited. On the one hand, it is helpful to introduce inert gas into the reaction chamber through the protective gas inlet pipe so that the air pressure in the reaction chamber is higher than the external atmospheric pressure, isolate the external air, and keep the atmosphere in the reaction chamber constant; on the other hand, it is helpful to avoid the formation of turbulence in the reaction area by the introduced gas, avoid affecting the contact between the reaction gas and the fiber, and avoid affecting the quality stability of the carbon nanotubes grown on the fiber surface. If the inner diameter is too large, more inert gas needs to be introduced to isolate the reaction chamber gas environment from the external environment, but this can easily affect the atmosphere in the reaction area, thereby affecting the uniform growth of carbon nanotubes on the fiber surface, resulting in poor product quality; if the inner diameter is too small, less inert gas can be introduced to isolate the reaction chamber gas environment from the external gas, but when the inner diameter is small, when the gas flows from the inlet or outlet tube to the inside of the reaction chamber, the gas flow rate is too large, and turbulence is also easily formed in the reaction area. The atmosphere in the reaction area is poorly constant, which will cause the uniform growth of carbon nanotubes on the fiber surface and affect the quality of the product.

[0041] In the above technical solution, the wire inlet pipe, the wire outlet pipe, the reaction gas inlet pipe, and the tail gas pipe are not limited to one, and multiple ones may be provided.

[0042] Preferably, in some embodiments, a plurality of reaction gas inlet pipes are arranged on the wall of the reaction chamber where the wire inlet pipe is located, and the atmosphere inside the reaction chamber is made uniform and stable by adjusting the air inlet angle and the number of the reaction gas inlet pipes.

[0043] Preferably, the inlet and outlet tubes are detachable to facilitate the operation of passing the fibers through the reaction chamber.

[0044] In some embodiments, the device also includes a heating system, which forms a heating area inside the reaction chamber. The reaction gas inlet pipe and the wire inlet pipe extend into the heating area inside the reaction chamber, so that the reaction gas can be fully utilized and the reaction gas is focused on the heating area, which helps to save resources.

[0045] In some embodiments, the reaction gas inlet pipe and the wire inlet pipe are arranged in parallel on the same wall of the reaction chamber, and the extension ports of the reaction gas inlet pipe and the wire inlet pipe inside the reaction chamber are flush. This helps to make the environment for the growth of carbon nanotubes on the fiber surface consistent, thereby ensuring the quality of the carbon nanotubes grown on the fiber surface.

[0046] In some embodiments, the ports of the reaction gas inlet pipe and the wire inlet pipe inside the reaction chamber both extend to the heating area, and the ports extending inside the reaction chamber are flush, so that the fibers can come into contact with the reaction gas after being exposed inside the reaction chamber. In this way, the fiber filaments are protected by the inert gas before reacting with the reaction gas, and the reaction conditions of the fibers in the heating area are more uniform, which is conducive to the growth of carbon nanotubes of uniform quality on the fiber surface.

[0047] The device provided by the present invention adopts a wire inlet tube and a wire outlet tube to transmit fiber filaments online, so the heating area inside the reaction chamber can be locally distributed, which is beneficial to simplifying the heating equipment and reducing the production input cost.

[0048] Preferably, in the aforementioned technical solution, the exhaust pipe only extends outside the reaction chamber, and the port close to the reaction chamber is flush with the inner wall of the reaction chamber, which helps the exhaust gas inside the reaction chamber to flow out of the reaction chamber smoothly.

[0049] In the above technical solution, in some embodiments, the side walls of the reaction chamber are respectively perpendicular to the top wall and the bottom wall of the reaction chamber, and the heating system is arranged above the top wall and / or below the bottom wall, which helps the heating system to form a heating area in the reaction chamber with a consistent heating temperature in each horizontal plane or each vertical plane, thereby helping to maintain the stable reaction temperature conditions of the fiber filaments in the heating area. In some embodiments, the top wall and the bottom wall are circular or regular polygonal; in other embodiments, it is preferred that the top wall and the bottom wall are both rectangular or square, and a heating system is arranged above the top wall of the reaction chamber and below the bottom wall of the reaction chamber, so that the reaction conditions of the fiber filaments in the heating area are more uniform, the temperature gradient of the heating area is small, and the quality of the carbon nanotubes formed on the surface of the fiber filaments is more stable; and it also helps to better realize that multiple filaments enter the reaction chamber from different fiber inlet tubes in parallel for reaction, and the reaction conditions are more uniform, which helps to improve the production scale and efficiency.

[0050] The present invention also provides a method for online continuous growth of carbon nanotubes on the surface of fibers, wherein the fiber filaments can enter the reaction system online through a fiber inlet channel to react with the reaction gas, and the fiber filaments can also leave the reaction system online through a fiber outlet channel to terminate the reaction with the reaction gas; the fiber inlet channel and the fiber outlet channel are protected by an inert gas.

[0051] The above scheme is adopted to isolate the atmosphere of the reaction system from the external gas environment, thereby maintaining the atmosphere inside the reaction system relatively constant, ensuring the stability of the growth environment of the fiber-growing carbon nanotubes inside the reaction system, and further ensuring the stability of product quality.

[0052] In the above scheme, the protective gas can be any inert gas. Preferably, the protective gas is a mixture of one or more gases selected from argon, nitrogen, helium, etc. These gases can not only better isolate the atmosphere of the reaction chamber from the external atmosphere, but also have little effect on the atmosphere of the heating area, and thus have little effect on the growth of carbon nanofibers on the fiber surface, thereby ensuring that the quality of the carbon nanofibers grown on the fiber surface is uniform and stable and the structure is uniform and controllable.

[0053] The aforementioned scheme comprises the following steps:

[0054] S1: the fiber filaments enter the reaction system from the fiber inlet channel and come out from the fiber outlet channel;

[0055] S2 uses inert gas to protect the wire inlet and outlet channels and exhaust the air from the reaction system;

[0056] S3 heats the reaction system to a preset temperature; in some embodiments, the preset temperature is 500-850°C, and in other embodiments, the preset temperature is preferably 600-750°C, and the preset temperature can be adaptively adjusted according to the type of catalyst.

[0057] S4 introduces the reaction gas, and the fiber begins to be transmitted at a predetermined wire transmission speed. In some embodiments, the catalyst precursor can be a catalyst solution containing one or more metal elements of iron, cobalt, nickel, and copper, and the catalyst gas precursor is obtained by atomization; the reducing gas is to reduce the cracking rate of the carbon source gas and improve the uniformity of the growth of carbon nanotubes, preferably hydrogen as the reducing gas; the carbon source gas can be one or a mixture of two or more of methane, acetylene, and ethylene.

[0058] Furthermore, in order to make the fiber react with the reaction gas in the heating area to smoothly grow carbon nanotubes and ensure the uniform quality of the carbon nanotubes grown on the fiber surface, in some embodiments of the present invention, a catalyst solution with a concentration of 0.1 to 0.5 mol / L is atomized into a catalyst gas precursor by a conventional method, and the catalyst solution is heated at a rate of 0.25 to 0.42 μL / min. -1 The speed diffuses into each liter of the reaction system; the flow rates of the reducing gas and the carbon source gas introduced into each liter of the reaction system are 15-50 sccm and 4-45 sccm, respectively. The masses of the catalyst gas precursor, the reducing gas and the carbon source gas in the reaction system are in direct proportion, that is, the higher the mass of the carbon source gas, the higher the catalyst gas precursor and the reducing gas in the reaction system.

[0059] In the above scheme, the present invention mixes the catalyst gas precursor, the reducing gas and the carbon source gas to form the reaction gas and introduces it into the reaction chamber and strictly limits the gas flow of each substance in the reaction system to ensure that the carbon nanotubes grown on the fiber surface are of good quality. If the concentration of the catalyst solution is too high, the density of the carbon nanotubes grown on the fiber surface is too large, and when the catalyst concentration is too high, the catalyst activity is too strong, so that the morphology of the carbon nanotubes grown on the fiber surface is uncontrollable, and some amorphous carbon is produced, affecting the final product quality; if the concentration of the catalyst solution is too low, the amount of carbon nanotubes grown on the fiber surface per unit time is small, if the reaction time is extended, the carbon nanotubes are seriously entangled, and the high-temperature reaction time is too long to damage the strength of the glass fiber, affecting the quality of the product; the present invention strictly limits the reducing gas and its flow rate, so that the reducing gas in the reaction gas acting on the fiber reduces the cracking rate of the carbon source gas, and reduces the catalyst to a suitable valence state, giving full play to the activity of the catalyst, making the growth conditions of the carbon nanotubes on the fiber surface controllable, and forming a good product quality. If the flow rate of reducing gas is too high, a large amount of catalyst will be reduced, the catalyst activity will be too strong, excessive carbon will be formed on the fiber surface in a short time, part of the carbon source will form amorphous carbon, and the carbon nanotubes grown on the fiber surface will be of poor quality; if the flow rate of reducing gas is too low, it will not be conducive to reducing the cracking rate of carbon source gas, the catalytic activity of the catalyst will be poor, affecting the growth of carbon nanotubes on the fiber surface, and further affecting the quality of the final product.

[0060] Further, in some embodiments of the aforementioned technical solution, the fiber transmission speed (hereinafter referred to as "wire speed") is 1 to 10 cm / min, which helps the fiber to fully react in the reaction chamber, and the quality of the carbon nanotubes grown on the fiber surface is uniform and stable. If the wire speed is too fast, the chemical reaction on the fiber surface is incomplete, which is not conducive to ensuring the quality of the carbon nanotubes grown on the fiber surface. If the wire speed is too slow, the reaction time is too long, there are too many carbon nanotubes, the morphology is uncontrollable, and thick nanotubes are produced, which are severely entangled, poor in quality, and low in efficiency.

[0061] Preferably, in the above technical solution, in order to ensure the stability of the atmosphere in the reaction area and prevent the growth of carbon nanotubes on the fiber surface from being affected by the flow rate and flow velocity of the inert gas introduced, preferably, the flow rate of the inert gas introduced per liter of the reaction system is 40-170 sccm, and more preferably, the flow rate of the inert gas introduced per liter of the reaction system is 100-145 sccm. If the flow rate of the inert gas is too high, it may affect the stability of the atmosphere in the reaction area, and further may affect the quality of the carbon nanotubes grown on the fiber surface; if the flow rate of the inert gas is too low, it cannot ensure that the air pressure inside the reaction chamber is greater than the outside, blocking the external gas, and the atmosphere inside the reaction chamber is poorly stable, which may cause the quality of the carbon nanotubes grown on the fiber surface to be affected.

[0062] The present invention also provides a method for growing carbon nanotubes on the surface of fiber filaments online continuously, using Figure 1 The device shown, in some embodiments, comprises the following steps:

[0063] 1) The fiber as the substrate is sequentially introduced from the wire inlet pipe into the reaction chamber and out from the wire outlet pipe, and the wire inlet end and the wire outlet end are respectively fixed on the transmission device. The fiber can be one or a mixed fiber of two or more of carbon fiber, glass fiber, silicon carbide fiber, quartz fiber or high silica fiber, and the above fibers have the conventional meaning in this field and can be commercially available. Preferably, the number of monofilaments of the fiber is any one of 1K, 3K, 6K, and 12K, and the specifications of the fiber are optimized. The conditions for growing carbon nanotube fibers from the fiber surface using the method provided by the present invention are more uniform and more unified.

[0064] 2) Introduce inert gas from the first protective gas inlet pipe and the second protective gas inlet pipe to fill the reaction chamber with protective gas to stabilize the atmosphere inside the reaction chamber.

[0065] 3) Heat the reaction chamber to reach a preset temperature.

[0066] 4) Introducing reaction gas into the reaction chamber through the reaction gas inlet pipe, and at the same time, the fiber is slowly moved from the wire inlet pipe to the wire outlet pipe according to the set wire feeding speed. During the operation of the device, all tail gas is discharged through the tail gas pipe. The reaction gas includes a catalyst gas precursor, a reducing gas and a carbon source gas.

[0067] The device and method for growing carbon nanotubes on the fiber surface online and continuously provided by the present invention not only realize the online and continuous growth of carbon nanotubes on the fiber surface and large-scale production, but also have good product quality stability.

[0068] The present invention will be further described below in conjunction with specific embodiments, but this should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made to the present invention by technicians in this field based on the above-mentioned contents of the present invention still fall within the scope of protection of the present invention.

[0069] Unless otherwise specified, the materials, reagents, etc. involved below are all commercially available products well known to those skilled in the art; unless otherwise specified, the methods described are all methods well known in the art. Unless otherwise defined, the technical terms or scientific terms used should have the common meanings understood by ordinary technicians in the field to which the present invention belongs.

[0070] Example 1

[0071] The present invention adopts Figure 1The device for growing carbon nanotubes on the fiber surface shown in the figure grows carbon nanotubes on the fiber surface, the inner diameters of the wire inlet pipe and the wire outlet pipe are circular and both have an inner diameter of 10 mm, the volume of the reaction chamber is 12 L, the inner diameters of the first protective gas inlet pipe and the second protective gas inlet pipe are circular and have an inner diameter of 10 mm, and the specific steps are as follows:

[0072] 1) Fix the ends of the glass fiber to the transmission devices on both sides through the inlet and outlet tubes.

[0073] 2) Nitrogen gas is introduced through the first protective gas inlet pipe and the second protective gas inlet pipe at a nitrogen flow rate of 1500 sccm. The nitrogen flow rate is maintained for 30 minutes, and the air in the reaction chamber is exhausted to stabilize the internal atmosphere.

[0074] 3) Adjust the reaction furnace so that the temperature of the heating area rises to 700°C.

[0075] 4) Open the valve of the reaction gas inlet pipe to introduce the reaction gas into the reaction chamber, wherein the hydrogen flow rate is 500 sccm, the acetylene flow rate is 300 sccm, and the catalyst precursor is a 0.2 mol / L ferrocene xylene solution atomized into a gas precursor.

[0076] At the same time, the transmission device is turned on to make the glass fiber start to move at a wire speed of 5 cm / min. The obtained glass fiber with carbon nanotubes grown thereon is collected by a winder combined with the tail transmission device.

[0077] The tensile strength, elongation and specific gravity of the glass fiber grown with carbon nanotubes are tested as follows:

[0078] The tensile strength and elongation were tested using a fiber extensometer;

[0079] The specific gravity of carbon nanotubes was obtained by thermogravimetric analysis;

[0080] The test results of the above items are shown in Table 1.

[0081] The glass fiber with carbon nanotubes obtained in this example was scanned by electron microscope, and the results were as follows: Figure 2 .

[0082] Example 2

[0083] The main difference between this embodiment and embodiment 1 is that: Step 3) the reaction furnace is adjusted to raise the temperature of the heating area to 600°C.

[0084] The tensile strength, elongation and specific gravity of carbon nanotubes were tested on the glass fiber grown with carbon nanotubes. The testing method was the same as that in Example 1. The results are shown in Table 1.

[0085] The glass fiber with carbon nanotubes obtained in this example was scanned by electron microscope, and the results were as follows: Figure 3 .

[0086] Example 3

[0087] The main difference between this embodiment and embodiment 1 is that: Step 4) the transmission device is turned on to allow the glass fiber to start moving at a wire speed of 1 cm / min.

[0088] The tensile strength, elongation and specific gravity of carbon nanotubes were tested on the glass fiber grown with carbon nanotubes. The testing method was the same as that in Example 1. The results are shown in Table 1.

[0089] The glass fiber with carbon nanotubes obtained in this example was scanned by electron microscope, and the results were as follows: Figure 4 .

[0090] Example 4

[0091] The main difference between this embodiment and embodiment 1 is that the inner diameters of the wire inlet pipe and the wire outlet pipe are both 12 mm, the inner diameters of the first protective gas inlet pipe and the second protective gas inlet pipe are circular and have an inner diameter of 11 mm. The specific steps are as follows:

[0092] Step 2) Argon gas is introduced through the first protective gas inlet pipe and the second protective gas inlet pipe at a flow rate of 800 sccm. The flow rate is maintained for 30 minutes, and the air in the reaction chamber is exhausted to stabilize the internal atmosphere.

[0093] Step 3) The temperature of the heating zone is raised to 600°C.

[0094] Step 4) The hydrogen flow rate is 200 sccm, the acetylene flow rate is 50 sccm, and the catalyst precursor is a 0.1 mol / L ferrocene xylene solution atomized into a gas precursor.

[0095] The glass fiber starts to move at a wire speed of 3 cm / min.

[0096] The tensile strength, elongation and specific gravity of carbon nanotubes were tested on the glass fiber grown with carbon nanotubes. The results are shown in Table 1.

[0097] Example 5

[0098] The main difference between this embodiment and embodiment 1 is that the inner diameters of the wire inlet pipe and the wire outlet pipe are both 8 mm, the inner diameters of the first protective gas inlet pipe and the second protective gas inlet pipe are circular and 9 mm in diameter, and the specific steps are as follows:

[0099] Step 2) Helium gas is introduced through the first protective gas inlet pipe and the second protective gas inlet pipe at a helium flow rate of 800 sccm, and maintained for 30 minutes to exhaust the air in the reaction chamber to stabilize the internal atmosphere.

[0100] Step 3) The temperature of the heating zone is raised to 750°C.

[0101] Step 4) The hydrogen flow rate is 300 sccm, the acetylene flow rate is 300 sccm, and the catalyst precursor is a 0.5 mol / L ferrocene xylene solution atomized into a gas precursor.

[0102] The glass fiber starts to move at a wire speed of 10 cm / min.

[0103] The tensile strength, elongation and specific gravity of carbon nanotubes were tested on the glass fiber grown with carbon nanotubes. The results are shown in Table 1.

[0104] Comparative Example 1

[0105] The main difference between this comparative example and Example 1 is that the catalyst precursor is a 0.01 mol / L ferrocene xylene solution atomized into a gas precursor.

[0106] The tensile strength, elongation and specific gravity of carbon nanotubes were tested on the glass fiber grown with carbon nanotubes. The testing method was the same as that in Example 1. The results are shown in Table 1.

[0107] The glass fiber with carbon nanotubes obtained in this comparative example was scanned by electron microscope, and the results were as follows: Figure 5 .

[0108] Comparative Example 2

[0109] The main difference between this comparative example and Example 1 is that the inner diameters of the wire inlet and outlet pipes are 15 mm, hydrogen is introduced into the first protective gas inlet pipe and the second protective gas inlet pipe, and the hydrogen flow rate is 250 sccm.

[0110] The tensile strength, elongation and specific gravity of carbon nanotubes were tested on the glass fiber grown with carbon nanotubes. The testing method was the same as that in Example 1. The results are shown in Table 1.

[0111] Comparative Example 3

[0112] The main difference between this comparative example and Example 1 is that the glass fiber starts to move at a wire speed of 15 cm / min.

[0113] The tensile strength, elongation and specific gravity of carbon nanotubes were tested on the glass fiber grown with carbon nanotubes. The testing method was the same as that in Example 1. The results are shown in Table 1.

[0114] Comparative Example 4

[0115] The main difference between this comparative example and Example 1 is that the wire inlet pipe and the wire outlet pipe are circular and have an inner diameter of 5 mm, and hydrogen is introduced into the first protective gas inlet pipe and the second protective gas inlet pipe, and the hydrogen flow rate is 800 sccm.

[0116] The tensile strength, elongation and specific gravity of carbon nanotubes were tested on the glass fiber grown with carbon nanotubes. The testing method was the same as that in Example 1. The results are shown in Table 1.

[0117] Table 1 Test results of various indicators

[0118] Group Tensile strength σb(MPa) Elongation εr(%) Carbon nanotube specific gravity (wt%) Example 1 1693 2.34 61.25 Example 2 1732 2.21 46.53 Example 3 1342 1.61 78.32 Example 4 1610 1.97 33.12 Example 5 1539 1.85 68.49 Comparative Example 1 1572 1.94 18.33 Comparative Example 2 1703 2.21 54.46 Comparative Example 3 1963 2.16 22.53 Comparative Example 4 1579 1.91 21.34

[0119] Combined with Table 1 and Appendix Figures 2 to 5 It can be seen that the novel chemical vapor deposition device and method provided by the present invention can realize the growth of carbon nanotubes on the surface of continuous fibers, and the product quality is good.

[0120] The technical features in the claims and / or the specification of the present invention may be combined, and the combination is not limited to the combination obtained by reference in the claims. The technical solution obtained by combining the technical features in the claims and / or the specification is also within the protection scope of the present invention.

[0121] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification, equivalent change and modification made to the above embodiment according to the technical essence of the present invention still falls within the scope of the technical solution of the present invention.

Claims

1. A device for growing carbon nanotubes on the surface of a fiber online and continuously, comprising a reaction chamber, the reaction chamber comprising a reaction gas inlet pipe and an exhaust pipe, characterized in that: It also includes: A wire inlet pipe is arranged on the wall of the reaction chamber; a first protective gas inlet pipe is arranged on the wall of the wire inlet pipe; The wire outlet pipe is arranged on the wall of the reaction chamber; and a second protective gas inlet pipe is arranged on the wall of the wire outlet pipe.

2. The device according to claim 1, characterized in that The inner diameters of the wire inlet pipe and the wire outlet pipe are circular, and their inner diameters are D1; the inner diameters of the first protective gas inlet pipe and the second protective gas inlet pipe are circular, and their inner diameters are D2, and D1:D2 is 0.7-1.4:

1.

3. The device according to claim 1, characterized in that It also includes a heating system, which forms a heating area inside the reaction chamber. The reaction gas inlet pipe and the wire inlet pipe extend to the heating area inside the reaction chamber.

4. The device according to claim 1, characterized in that The reaction gas inlet pipe and the wire inlet pipe are arranged in parallel on the same wall of the reaction chamber, and the reaction gas inlet pipe and the wire inlet pipe are flush with the extension ports inside the reaction chamber.

5. The device according to claim 3, characterized in that The side walls of the reaction chamber are respectively perpendicular to the top wall and the bottom wall; the heating system is arranged above the top wall and / or below the bottom wall.

6. A method for growing carbon nanotubes on the surface of fiber filaments online continuously, characterized in that: The fiber filaments can enter the reaction system online through the wire inlet channel to react with the reaction gas, and the fiber filaments can also leave the reaction system online through the wire outlet channel to terminate the reaction with the reaction gas; the wire inlet channel and the wire outlet channel are protected by inert gas.

7. The method according to claim 6, characterized in that The inert gas is a mixture of one or more of nitrogen, argon and helium; the reaction gas includes a catalyst gas precursor, a reducing gas and a carbon source gas; the catalyst precursor is a mixture of one or more metal elements selected from iron, cobalt, nickel and copper.

8. The method according to claim 6 or 7, characterized in that: It includes the following steps: S1: the fiber filaments enter the reaction system from the fiber inlet channel and come out from the fiber outlet channel; S2 uses inert gas to protect the wire inlet and outlet channels and exhaust the air from the reaction system; S3: heating the reaction system to a preset temperature; S4: The reaction gas is introduced and the fiber filaments begin to be transmitted at a predetermined speed.

9. The method according to claim 8, characterized in that The catalyst solution is atomized to form a catalyst gas precursor, the catalyst solution concentration is 0.1-0.5 mol / L, and the catalyst solution is atomized at a rate of 0.25-0.42 μL / min. -1 The speed diffuses into each liter of the reaction system; the flow rates of the reducing gas and the carbon source gas introduced into each liter of the reaction system are 15-50 sccm and 4-45 sccm respectively; the flow rate of the inert gas introduced into each liter of the reaction system is 40-170 sccm.

10. The method according to claim 9, characterized in that The transmission speed of the fiber filaments in the reaction system is 1-10 cm / min; the preset temperature is 500-850°C.

Images