KR20110075096A - Method of preparing carbon nanotube complex structures - Google Patents

Abstract

PURPOSE: A method for manufacturing a carbon nano-tube composite is provided to increase the manufacturing yield thereof by directly growing carbon nano-tube on fiber or a fiber support. CONSTITUTION: Fiber or a fiber structure and a metal catalyst are immersed in an aqueous dispersion solvent(S10). The metal catalyst is attached on the fiber or the fiber structure through an ultrasound wave process(S20). A carbon source is supplied to grow carbon nano fibers based on the metal catalyst through a chemical vapor deposition method(S30). The fiber of the fiber structure is carbon fiber, glass fiber, fabric based on the carbon fiber and the glass fiber, or a three dimensional fiber structure. The aqueous dispersion solvent is distilled water or an alcohol solution. The metal catalyst is selected from a group including iron, molybdenum, cobalt, nickel, titanium, chromium, ruthenium, manganese, rhenium, rhodium, palladium, vanadium, and the combination or the alloy of the same.

Description

Method of Preparing Carbon Nanotube Complex Structures

The present invention relates to a method for producing a carbon nanotube composite structure, and more particularly, to a method for producing a carbon nanotube composite structure by directly growing carbon nanotubes on a fiber or a fiber structure surface.

Carbon nanotubes are cylindrical carbon materials having a diameter of about 1 to 10 nm in a nanometer size and having a rounded shape of a graphite surface having a length of several μm. Graphite has a strong and flat hexagonal plate-like structure due to its unique bond arrangement. The upper and lower portions of the film are filled with free electrons, and the electrons move in parallel with the film in a discrete state. Since the graphite layer is wound into a spiral to form carbon nanotubes, the edges are bonded at different points and the electrical properties of the nanotubes are a function of structure and diameter. Rev. (1992) B 46: 1804 and Phys. Rev. Lett. (1992) 68: 1579. In other words, changing the helical or chirality of carbon nanotubes changes the motion of free electrons, which results in free movement of free electrons, allowing the carbon nanotubes to react like metals or barriers like semiconductors. Overcome it. As described above, carbon nanotubes exhibit various electrical properties from insulators to semiconductors and metals due to differences in structure and diameter. Carbon nanotubes are excellent in mechanical properties such as flat panel display devices, transistors, and energy storage materials because of their excellent mechanical robustness and chemical stability, their ability to exhibit both semiconductor and conductor properties, and their small diameter, length, and hollowness. It shows the property, and the applicability as nanomaterial of various electronic devices is very large.

Therefore, the method of laminating on a suitable substrate for various applications of carbon nanotubes has also been actively studied, and many mechanisms and methods have been proposed. However, the proposed methods are sufficiently solved in terms of productivity in synthesis and product quality obtained. There is no way.

For example, Korean Patent No. 829001 describes a method of dispersing ferrocene powder, which is a metal catalyst particle, in a xylene solution and then dispersing it, and then adding a glass fiber or a carbon fiber support to a mixed solution in which the metal catalyst particle is dispersed. A method of synthesizing carbon nanofibers by chemical vapor deposition by dip coating a mixture of particles and a solution, putting a glass fiber or carbon fiber support in a mixed solution into a drier, and supplying a carbon source to a reactor in a reducing atmosphere. It is starting.

According to this method, however, the metal catalyst is dispersed in xylene, and the dispersion solution is impregnated with a glass fiber support or a carbon fiber support to dip coating the metal catalyst and remove xylene remaining on the fiber support. Because it has to go through a drying step, there is a problem that causes environmental pollution because the process is complicated, the production cost is increased and the organic solvent must be used.

The present invention is to overcome the above-mentioned problems of the prior art, one object of the present invention is to provide a method for producing a carbon nanotube composite structure that can directly grow carbon nanotubes on a fiber or fiber support by a simple process To provide.

One aspect of the present invention for achieving the above object is

Impregnating the metal catalyst and the fiber or fiber structure in an aqueous dispersion solvent;

Attaching a metal catalyst onto the fiber or the fiber structure by sonication after impregnation; And

It relates to a method for producing a carbon nanotube composite structure comprising supplying a carbon source to grow carbon nanofibers by chemical vapor deposition from the metal catalyst.

According to the present invention, it is possible to grow carbon nanotubes directly on a fiber or a fiber structure by a simple process without using an organic solvent, thereby reducing process costs and increasing production rate. In addition, since organic solvents that cause environmental pollution are not used, environmental improvement and organic solvent purchase / treatment costs can be reduced.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

1 is a process flowchart of a method of manufacturing a carbon nanotube composite structure according to an embodiment of the present invention. Referring to FIG. 1, in one embodiment of the present invention, after impregnating a metal catalyst with a fiber or fiber structure in an aqueous dispersion solvent (S10), the metal catalyst is attached onto the fiber or fiber structure by ultrasonication (S20). Subsequently, a carbon source is supplied to grow carbon nanofibers from the metal catalyst by chemical vapor deposition to grow carbon nanotubes directly on the surface of the fiber or the fibrous structure to prepare a carbon nanotube composite structure (S30).

In the present invention, the fiber for attaching the catalyst may be carbon fiber or glass fiber, and the like, and the fiber structure includes a two-dimensional fiber structure such as a fabric composed of such carbon fiber or glass fiber or a three-dimensional fabric. In addition, fibers and fiber structures may be used together as necessary.

In the present invention, an organic solvent is not used, and an aqueous dispersion solvent such as distilled water, alcohol, DMF, NMP, THF, DMAc, or the like is used instead. Therefore, according to the present invention, carbon nanotubes can be grown directly from the surface of fibers or fiber structures without the problem of environmental pollution.

Examples of the metal catalyst usable in the present invention are not particularly limited, but for example from the group consisting of iron, molybdenum, cobalt, nickel, titanium, chromium, ruthenium, manganese, rhenium, rhodium, palladium, vanadium, alloys or combinations thereof Any one selected can be used. The size of the metal catalyst particles is not particularly limited. For example, nanoparticles of a catalyst in the range of about 0.5 nanometers to about 30 nanometers may be used.

In the present invention, ultrasonication is performed to attach the metal catalyst onto the fiber or the fiber structure. Ultrasound is preferably relatively strong in energy. The intensity of the energy of the ultrasonic wave may vary depending on the type of fiber or fiber structure used, the amount of the dispersion solvent, the ultrasonic irradiation time, and the like. For example, the ultrasonic wave of about 20 to 50 KHz may be irradiated for about 0.5 to 1 hour.

If the metal catalyst is attached on the fiber or the fiber structure, it is not necessary to go through the drying step separately, but it is sufficient to remove the moisture to the extent that the water droplets do not fall off. When the water is removed, carbon nanotubes are grown directly from the surface of the fiber or the surface of the fiber structure by chemical vapor deposition. The catalyst-attached fibers or fiber structures are introduced into a chemical vapor deposition growth reactor, and the carbon nanotubes are grown by flowing a reaction gas containing a carbon source after increasing the reactor chamber temperature to a predetermined growth temperature. At this time, the diameter and length of the synthesized carbon nanotubes can be controlled by adjusting the pressure in the reactor or the flow rate of the gas.

The catalyst is raised to the desired growth temperature in a suitable atmosphere before the start of carbon nanotube growth using a carbon source. The carbon nanotube growth temperature is typically about 500 ° C to about 1000 ° C, preferably about 600 ° C to about 900 ° C.

Examples of suitable carbon sources are aliphatic hydrocarbons, aromatic hydrocarbons, carbonyls, halogenated hydrocarbons, silylated hydrocarbons, alcohols, esters, aldehydes, ketones, acids, phenols, esters, amines, alkylnitriles, thioethers, cyanates Acid salts, nitroalkyl, alkyl nitrates and one or more mixtures thereof, but are not necessarily limited to these. Typically, methane, ethane, propane, butane, ethylene, acetylene, carbon monoxide, benzene and methylsilane may be used as the carbon source.

On the other hand, other reaction gases such as hydrogen and ammonia, which play important roles in carbon nanotube growth, may also be introduced. In addition, carrier gases such as argon, nitrogen and helium may be introduced.

According to the method of the present invention, carbon nanotubes having a predetermined length can be grown directly and uniformly on the surface of the fiber or the fiber structure, and the diameter of the carbon nanotubes grown on the surface of the fiber or the fiber structure is typically about 20 nanometers to About 50 nanometers, specifically about 25 nanometers to about 35 nanometers. The diameter size distribution is about 10 nanometers to about 15 nanometers, specifically about 60 nanometers to about 70 nanometers.

Fiber or fiber structure in which carbon nanotubes are grown on the surface obtained in the present invention is a source of emission of various devices, vacuum fluorescence display, white light source, field emission display, lithium ion 2 It can be widely used in secondary battery electrodes, hydrogen storage fuel cells, nanowires, AFM / STM tips, single-electron devices, gas sensors, medical micro components, and high-performance composites. In addition, the composite may be used in wind turbine blades, automotive exterior panels, car frames, aircraft body and wings, bicycle frames, golf clubs, yachts, such as yachts.

The method of the present invention can be applied to the growth of carbon nanotubes as well as many other nanometer sized nanometric filamentary structures directly on a fiber or fiber structure.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the following Examples are only for explaining specific embodiments of the present invention, and the present invention is not limited by the following Examples.

Example

Example  One

1 g of iron / molybdenum is placed in 300 g of distilled water as a metal catalyst, and the carbon fiber and the carbon fiber fabric are impregnated. It is then placed in an ultrasonicator at an intensity of 28 kHz After sonication for 30 minutes, the carbon fiber and the carbon fiber fabric are taken out. The water of the carbon fibers and the carbon fiber fabrics were removed and subjected to a reduction treatment under hydrogen gas atmosphere at 650 ° C. for 1 hour using a chemical vapor deposition apparatus, followed by treatment for 1 hour in ethylene atmosphere to grow CNTs. 1 and 2 show cross-sectional and side pictures of carbon fibers in which carbon nanotubes are grown on the surface thus obtained. 1 and 2 it can be seen that the carbon nanotubes are uniformly grown around the carbon fiber.

Example  2

Except that based on the glass fiber was carried out in the same manner as in Example 1, the carbon nanofibers were grown directly on the surface of the glass fiber, and the side photo of the glass fiber synthesized on the surface of the carbon nanotubes are shown in Figure 3 .

Although various embodiments of the present invention have been described in detail with reference to preferred embodiments of the present invention, it will be apparent to those skilled in the art that the present invention may be variously changed or modified without departing from the spirit and scope of the present invention. Obviously, all such changes and modifications should be construed as being included in the protection scope of the present invention.

1 is a process flowchart of a method of manufacturing a carbon nanotube composite structure according to an embodiment of the present invention.

FIG. 2 is a photograph showing a cross section of carbon fibers synthesized with carbon nanotubes on the surface obtained in Example 1. FIG.

Figure 3 is a side photograph of the carbon fiber synthesized carbon nanotubes on the surface obtained in Example 1.

Figure 4 is a side photograph of the glass fiber synthesized carbon nanotubes on the surface obtained in Example 2

Claims (7)

Impregnating the metal catalyst and the fiber or fiber structure in an aqueous dispersion solvent; Attaching a metal catalyst on the fiber or the fiber structure by sonication after impregnation; And Supplying a carbon source to grow carbon nanofibers by chemical vapor deposition from the metal catalyst. The method of claim 1, wherein the fiber or fiber structure is carbon fiber, glass fiber, fabric made of carbon fiber or glass fiber, or a three-dimensional fiber structure. The method of claim 1, wherein the aqueous dispersion solvent is distilled water or an alcohol solvent. The method of claim 1, wherein the catalyst is carbon nano, characterized in that selected from the group consisting of iron, molybdenum, cobalt, nickel, titanium, chromium, ruthenium, manganese, rhenium, rhodium, palladium, vanadium, alloys or combinations thereof Method of manufacturing a tube composite structure. The method of claim 1, wherein the ultrasonication step is a step of irradiating the ultrasonic wave of about 20 ~ 50kHz about 0.5 ~ 1 hour. The process of claim 1 wherein the carbon source is an aliphatic hydrocarbon, an aromatic hydrocarbon, a carbonyl, a halogenated hydrocarbon, a silicated hydrocarbon, an alcohol, an ester, an aldehyde, a ketone, an acid, a phenol, an ester, an amine, an alkylnitrile, a thioether, a cyanate. , Nitroalkyl, alkyl nitrate, and a method for producing a carbon nanotube composite structure, characterized in that at least one selected from the group consisting of. The method of claim 6, wherein the carbon source is at least one selected from the group consisting of methane, ethane, propane, butane, ethylene, acetylene, carbon monoxide, and benzene.

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