KR20200034090A - Preparation method of cnt fiber aggregates - Google Patents

Abstract

The present invention relates to a carbon nanotube fiber manufacturing method, which can improve manufacturing efficiency of the carbon nanotube fiber in a simple process without additional equipment. Specifically, the production of the carbon nanotube fiber can be improved by controlling a supplying source when the carbon nanotube is being manufactured and thus easily adjusting the linear density of the carbon nanotube fiber. The carbon nanotube fiber manufactured by the method according to the present invention is expected to be used in various fields such as a reinforcing material of a multifunctional composite material, a deformation and damage detector using a stable and repeatable piezo-resistance effect, a transmission line using high conductivity, and an electrochemical device using a high specific surface area, excellent mechanical properties, and excellent electrical conductivity, for example, a microelectrode material for detecting biomaterials, a supercapacitor, an actuator, etc.

Description

Carbon nanotube fiber manufacturing method {PREPARATION METHOD OF CNT FIBER AGGREGATES}

The present invention relates to a carbon nanotube fiber manufacturing method in which the linear density of carbon nanotube fibers made of carbon nanotubes is adjusted to a desired range.

Carbon Nanotube (CNT), a type of carbon allotrope, is a material with a diameter of several to several tens of nanometers and has a length of several hundreds of μm to several mm. Due to its physical properties and high aspect ratio, research has been conducted in various fields. The inherent properties of these carbon nanotubes are due to the sp ² bond of carbon, stronger than iron, lighter than aluminum, and exhibiting electrical conductivity comparable to metal. The types of carbon nanotubes are largely based on the number of nanotubes, single-wall carbon nanotube (SWNT), double-wall carbon nanotube (DWNT), and multi-wall carbon nanotube (multi- It can be classified as Wall Carbon Nanotube, MWNT, and is divided into zigzag, armchair, and chiral structures according to asymmetry / chirality.

Recently, many carbon nanotube fiberization studies have been conducted to prepare a carbon nanotube structure that sufficiently expresses the properties of a carbon nanotube.

Examples of methods for fiberizing carbon nanotubes include 'coagulation spinning', 'liquid-crystalline spinning' and 'direct spinning'.

The coagulation method is a carbon nanotube by injecting a dispersion solution containing a carbon nanotube and a dispersant into a polymer solution to allow the dispersant in the dispersion solution to escape into the polymer solution and replace the site with a polymer to act as a binder. It is a method of fiberizing the tube.

The liquid crystal spinning method is a method in which a carbon nanotube solution is fiberized by using a property of forming a liquid crystal under specific conditions. This method has the advantage of being able to make carbon nanotube fibers with good orientation, but has a disadvantage that the spinning speed is very slow and the liquid crystal formation conditions of the carbon nanotubes are difficult.

In the direct spinning method, a liquid carbon source and a catalyst are injected together with a carrier gas into the upper inlet of a vertically heated high-temperature furnace to synthesize carbon nanotubes in the furnace and to the heating furnace together with a carrier gas. This is a method of obtaining fibers by winding-up the carbon nanotube aggregates that have come down to the inside or outside of a heating furnace.

Carbon nanotubes (CNT) can be roughly divided into single-wall CNTs and multi-wall CNTs according to the number of graphene layers. Among the multi-walled CNTs, two layers have distinct application fields, and the double-walled CNTs may be classified and classified. Although the mechanical strength of CNT itself, especially the tensile strength, is very excellent, exceeding 100 GPa, the synthesized CNT is limited in application because it is a short fiber having a short length. In order to solve this problem, a method of making CNT fibers, which are long fibers, by connecting CNTs, which are short fibers, has been recently studied.

Variables affecting the strength of CNT fibers include CNT length, diameter, defects, internal voids, alignment between CNTs, and attraction.

The breaking strength of CNT fibers increases as the linear density of the fibers increases. Therefore, in order for CNT fibers to be applied to actual industrial fields, the strength to withstand the fibers before fracture is important, so the linear density properties of the fibers are important. In addition, since the linear density improvement of CNT fibers is associated with an increase in fiber production, it has a very important meaning for commercialization of CNT fibers.

Therefore, there is a need for a method that can adjust the linear density of CNT fibers to a desired level.

An object of the present invention is to provide a method that can adjust the linear density of the carbon nanotube fibers to the desired range.

In order to solve the above problems, the present invention

In preparing a carbon nanotube fiber by reacting a carbon source in a reactor in the presence of a catalyst and a cocatalyst,

Provided is a carbon nanotube fiber manufacturing method, wherein the linear density (Tex) of the carbon nanotube fiber satisfies the relationship of Equation 1.

[Equation 1]

선밀도(Tex)

(-0.00562)A + 0.3(-0.00562) A + 0.1

Linear density (Tex)

(-0.00562) A + 0.3

In Equation 1, A is a co-catalyst / catalyst molar ratio, and linear density (tex) represents the weight (g) of fibers per 1 km of fiber length.

According to one embodiment, the carbon nanotube linear density (Tex) may be adjusted according to Equation (2).

[Equation 2]

Linear Density (Tex) = (-0.00562) A + 0.238

In Equation 2, A and linear density are as defined in Equation 1.

According to one embodiment, the catalyst includes at least one selected from the group consisting of iron, nickel, cobalt, platinum, ruthenium, molybdenum, vanadium, and oxides thereof, and the cocatalyst is a compound containing a sulfur (S) atom Can be

In addition, the co-catalyst may include one or more selected from the group consisting of methanethiol, methyl ethyl sulfide, dimethyl thioketone, thiophenol, diphenyl sulfide, benzothiophene and thiophene.

In addition, the catalyst may be in the form of a metallocene.

According to one embodiment,

Injecting a carbon source, a catalyst and a co-catalyst into the reactor;

Raising the temperature of the reactor;

Adjusting the molar ratio of co-catalyst / catalyst; And

It may include the step of recovering the carbon nanotube fibers formed from a spinning material containing a carbon source by a winding means.

According to one embodiment, the reactor may include a step of injecting a reducing gas containing hydrogen gas, ammonia gas or a mixed gas thereof.

In addition, it may include the step of injecting a carrier gas containing an inert gas.

According to one embodiment, the carbon source may be a liquid or gaseous carbon source, methane, ethylene, acetylene, methylacetylene, vinylacetylene, ethanol, methanol, propanol, acetone, xylene, chloroform, ethylacetic acid, diethyl ether, Polyethylene glycol, ethyl formate, mesitylene, tetrahydrofuran (THF), dimethylformamide (DMF), dichloromethane, hexane, benzene, toluene, xylene, carbon tetrachloride and pentane. have.

According to one embodiment, the catalyst, co-catalyst and carbon source can be reacted at a temperature of 1,000 to 3,000 ℃.

According to another embodiment of the present invention, there is provided a carbon nanotube fiber prepared according to the method as described above.

Other specific details of the embodiments of the present invention are included in the following detailed description.

The present invention can improve the production efficiency of carbon nanotube fibers in a simple process without additional equipment. Specifically, the production amount can be improved by controlling the linear density of the carbon nanotube fibers. The carbon nanotube fiber produced by the method according to the present invention is a reinforcing material of a multifunctional composite material, a deformation and damage detector using a stable and repeatable piezo-resistance effect, a transmission line using high conductivity, a high specific surface area, excellent mechanical properties, and electrical conductivity. It is expected that it can be applied to various fields such as used electrochemical devices, for example, microelectrode materials for detecting biomaterials, supercapacitors, and actuators.

1 is a graph showing the relationship between the cocatalyst / catalyst molar ratio and linear density.

The present invention can be applied to a variety of transformations and may have various embodiments, and specific embodiments will be illustrated in the drawings and described in detail. However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all conversions, equivalents, and substitutes included in the spirit and scope of the present invention. In the description of the present invention, when it is determined that a detailed description of known technologies related to the present invention may obscure the subject matter of the present invention, the detailed description will be omitted.

As used herein, the term "aggregate" may be used interchangeably with "aggregate," and may be understood to mean a collection of singular entities.

As used herein, the term “injection” may be used interchangeably with “inflow, input” in the present specification, and may be understood to mean flowing or injecting liquid, gas, or heat into a required place. .

In this specification, the term "carbon nanotube fiber" refers to both carbon nanotubes formed by growing in a fiber form or a plurality of carbon nanotubes formed by fusion in a fiber form.

Unless otherwise specified in this specification, the expression "to" is used as an expression including the corresponding numerical value. Specifically, for example, the expression "1 to 2" means not only to include 1 and 2, but also to include both numbers between 1 and 2.

Hereinafter, a method of manufacturing a carbon nanotube fiber according to an embodiment of the present invention will be described in more detail.

According to one embodiment, the present invention may include a step of preparing a carbon nanotube fiber by injecting a reaction gas containing a carbon source into a reaction tube equipped with a heating furnace together with a catalyst and a transport gas.

Technologies for manufacturing carbon nanotube fibers include coagulation spinning, liquid crystal spinning, direct spinning, and the like, for example, which are formed immediately after the injection of the spinning raw material in the reactor using a chemical vapor deposition method (CD, chemical deposition). The process of directly emitting carbon nanotubes can be followed.

In direct spinning, carbon nanotubes are synthesized in a heating furnace by injecting a gaseous or liquid carbon source and a catalyst together with a carrier gas into a high-temperature furnace inlet, and heating the furnace with a carrier gas. It is a method to obtain the fiber by wind-up (wind-up) the carbon nanotube fiber discharged to the outlet of the inside or outside of the heating furnace.

The spinning raw material containing the carbon source is carbonized and graphitized while flowing from the top to the bottom of the furnace or from the bottom to the top to form carbon nanotube fibers composed of a continuous aggregate of carbon nanotubes.

According to a specific embodiment, the present invention is a step of introducing a catalyst, a co-catalyst, a carbon source and a transfer gas into a reaction tube equipped with a heating furnace; And

It provides a carbon nanotube fiber manufacturing method comprising the step of recovering the carbon nanotube (CNT) fibers discharged to the outlet of the bottom of the reaction tube by the winding means.

The present invention can form a carbon nanotube fiber whose linear density is controlled by adjusting a molar ratio of a catalyst and a cocatalyst among raw materials injected to produce a carbon nanotube fiber.

The linear density of the carbon nanotube fiber is expressed as the weight (g) of the fiber per 1 km of fiber length, and the unit is tex. For example, if 1 kilogram of fiber weighs 1 gram, it is said to be 1 tex.

Specifically, the present invention,

In preparing a carbon nanotube fiber by reacting a carbon source in the presence of a catalyst and a co-catalyst,

Provided is a carbon nanotube fiber manufacturing method, wherein the linear density (Tex) of the carbon nanotube fiber satisfies the relationship of Equation 1. Here, the linear density of the fiber is expressed by the weight (g) of the fiber per 1 km of the fiber yarn, and the unit is tex.

[Equation 1]

선밀도(Tex)

(-0.00562)A + 0.3(-0.00562) A + 0.1

Linear density (Tex)

(-0.00562) A + 0.3

In Equation 1, A is a co-catalyst / catalyst molar ratio, and linear density (tex) represents the weight (g) of fibers per 1 km of fiber length.

In the same range as in Equation 1, the molar ratio of the cocatalyst / catalyst and the linear density of the carbon nanotube fibers have a linear proportional relationship by Equation 1.

According to one embodiment, the linear density (Tex) of the carbon nanotube fiber according to the present invention is, for example, (-0.00562) A + 0.15 to (-0.00562) A + 0.3, for example (-0.00562) A + 0.186 To (-0.00562) A + 0.284.

According to one embodiment, the linear density (Tex) of the carbon nanotube fiber may be adjusted according to Equation (2).

[Equation 2]

Linear Density (Tex) = (-0.00562) A + 0.238

In Equation 2, A and linear density are as defined in Equation 1.

According to one embodiment, when the produced carbon nanotube fibers are wound and recovered, the coiling speed affects the orientation of the carbon nanotubes in the fiber in the fiber axial direction, and the thermal, electrical, Since the physical properties are determined, for example, it may be wound in a range of 1 to 100 m / min, but is not limited thereto, and may be selected according to the purpose.

According to one embodiment, the temperature of the reaction zone in the reactor can be maintained at a temperature of, for example, 1,000 to 3000 ° C, for example 1000 to 2,000 ° C, for example 1,000 to 1,500 ° C, or 1,000 to 1,300 ° C, for example For example, it may be 1,150 to 1,300 ° C. When the reaction temperature is too high, a problem that carbon nanotube fibers are not formed may occur, and when the reaction temperature is too high, a problem that carbon nanotubes are vaporized may occur.

According to one embodiment, the carrier gas (carrier gas) may include one or more selected from the group consisting of carbon source gas, inert gas and reducing gas. In addition, the reducing gas may include a gas containing hydrogen, ammonia, or a mixture thereof.

As the transport gas, for example, hydrogen gas may be injected at a gas hourly velocity (GHSV) of 10 to 60 hr ⁻¹ , for example, 20 to 35 hr ⁻¹ . The gas space velocity is a value measured at a standard state (0 ° C, 1 bar), which means the ratio of the volume flow rate of the supplied gas and the reactor volume, and the value given by the unit time in hours.

The inert gas may be, for example, a gas containing nitrogen, helium, neon, argon, krypton, xenon, radon, or a mixture thereof, and such an inert gas is chemically stable so that electrons do not exchange or share electrons. Because it has, it can play a role of allowing the carbon nanotube to flow and move due to the inflow of gas without reaction with the carbon nanotube (CNT).

According to one embodiment, the carbon source may be a liquid or gaseous carbon source, and may be selected in consideration of molecular weight distribution, concentration, viscosity, surface tension, dielectric constant and solvent properties. For example, methane, ethylene, acetylene, methyl acetylene, vinyl acetylene, ethanol, methanol, propanol, acetone ), Xylene, chloroform, ethyl acetate, diethyl ether, polyethylene glycol, ethyl formate, mesitylene, tetra In the group consisting of hydrofuran (THF), dimethylformamide (DMF), dichloromethane, hexane, benzene, toluene, xylene, carbon tetrachloride and pentane It may include one or more selected.

Specifically, the liquid carbon source is ethanol, methanol, propanol, acetone, xylene, chloroform, ethyl acetate, diethyl ether ether, polyethylene glycol, ethyl formate, mesitylene, tetrahydrofuran (THF), dimethylformamide (DMF), dichloromethane, hexane (hexane) hexane), benzene, toluene, xylene, carbon tetrachloride, and pentane. For example, ethanol, xylene, diethyl ether, polyethylene glycol, propanol, acetone, ethyl formate, benzene ( It may include any one or more selected from the group consisting of benzene), hexane, toluene, xylene and mesitylene.

The gaseous carbon source may include one or more selected from the group consisting of methane, ethylene, acetylene, methyl acetylene and vinyl acetylene.

According to one embodiment, the catalyst may include one or more selected from the group consisting of iron, nickel, cobalt, platinum, ruthenium, molybdenum, vanadium and oxides thereof, and may include, for example, iron, nickel or cobalt You can. In addition, the catalyst may be in the form of a metallocene, such as ferrocene.

According to one embodiment, the present invention further includes a co-catalyst. The cocatalyst is a substance that is not included in the catalytic cycle in itself in the catalytic reaction, but is converted into an active catalyst or generates an active catalyst, and the CNT is synthesized after the catalyst is formed. Specifically, the cocatalyst can be selected from elemental sulfur, sulfur-containing compounds and combinations thereof. Sulfur-containing compounds are, for example, methanethiol, methyl ethyl sulfide, dimethyl thioketone, thiophenol, diphenyl sulfide, benzothiophene (benzothiophene) and thiophene (thiophene). It may also include, for example, thiophene, sulfur or combinations thereof. Specifically, thiophene or sulfur increases the rate of formation of catalyst particles in the reactor to help synthesize high-concentration carbon nanotubes, and allows continuous fiber production.

Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art to which the present invention pertains can easily practice. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein.

Example

At the top of the vertical reactor, ferrocene is injected at a rate of 15 to 40 g / hr and thiophene at 50 to 200 g / hr, and methane is injected at a gas space velocity of 1 to 2 ^{hr -1} (GHSV, gas hourly space velocity), and hydrogen as a transport gas was introduced into the top of a vertical cylindrical reaction tube at a temperature of 1,200 to 1,250 ° C with a GHSV of 25 to 30 hr ^-1 . The temperature of the reactor was heated to 1,200 to 1,300 ° C, and carbon nanotube fibers were prepared by adjusting the molar ratio of co-catalyst / catalyst as shown in Table 1. Carbon nanotube fibers discharged to the outlet at the bottom of the reactor were wound with a winding means composed of bobbins.

The linear density of the recovered carbon nanotube aggregate fibers was measured using FAVIMAT + (Textechno). The linear density was calculated by the vibration method according to ASTM D1557 standard. The gauge length is 2.0 cm, and was measured after applying pre-tension to 80% of the approximate linear density value measured with a precision balance to improve accuracy.

Specifically, the linear density measurement was performed by applying a tensile force to both ends of a single fiber to apply tension to the entire fiber, and then applying vibration to the fiber to measure the resonance frequency, and was calculated using the following equation.

T _t = FV / (4 · f ² · L ² )

T _t = linear density (unit: tex)

FV = pre-tensioning force

f = resonance frequency

L = test section length

The test speed was conducted at 2.0 mm / min.

Table 1 shows the results of linear density measurements.

According to the results in Table 1, a graph showing the relationship between the molar ratio of the co-catalyst (S) / catalyst (Fe) and the linear density (Tex) is shown in FIG. 1.

As shown in Figure 1, it can be seen that the linear density (Tex) has a linear proportional relationship with the molar ratio of the co-catalyst / catalyst in the range of (-0.00562) A + 0.186 to (-0.00562) A + 0.284.

As described above, it was confirmed that the linear density of the carbon nanotube fibers can be easily adjusted by adjusting the molar ratio of the co-catalyst / catalyst.

The specific parts of the present invention have been described in detail above. For those skilled in the art, this specific technology is only a preferred embodiment, and it is obvious that the scope of the present invention is not limited thereby. something to do. Therefore, the substantial scope of the present invention will be defined by the appended claims and their equivalents.

Claims (12)

In preparing a carbon nanotube fiber by reacting a carbon source in a reactor in the presence of a catalyst and a cocatalyst,
Method for producing carbon nanotube fiber, the linear density (Tex) of the carbon nanotube fiber satisfies the relationship of Equation 1:
[Equation 1]
(-0.00562) A + 0.1

Linear density (Tex)

(-0.00562) A + 0.3
In Equation 1, A is the co-catalyst / catalyst molar ratio, and linear density (tex) represents the weight (g) of fibers per 1 km of fiber length. According to claim 1,
Carbon nanotube fiber manufacturing method for adjusting the linear density (Tex) of the carbon nanotube fiber according to Equation 2:
[Equation 2]
Linear Density (Tex) = (-0.00562) A + 0.238
In Equation 2, A is the co-catalyst / catalyst molar ratio, and linear density (tex) represents the weight (g) of fibers per 1 km of fiber length. According to claim 1,
The catalyst comprises at least one selected from the group consisting of iron, nickel, cobalt, platinum, ruthenium, molybdenum, vanadium and oxides thereof,
The co-catalyst is a compound containing a sulfur (S) atom, carbon nanotube fiber manufacturing method. According to claim 1,
The cocatalyst is methanethiol, methyl ethyl sulfide, dimethyl thioketone, thiophenol, diphenyl sulfide, benzothiophene, and Carbon nanotube fiber manufacturing method comprising at least one selected from the group consisting of thiophene (thiophene). According to claim 1,
Method for producing carbon nanotube fibers in which the catalyst is in the form of a metallocene. According to claim 1,
Injecting a carbon source, a catalyst and a co-catalyst into the reactor;
Raising the temperature of the reactor;
Adjusting the molar ratio of co-catalyst / catalyst; And
And recovering the carbon nanotube fibers formed from the spinning material containing the carbon source by a winding means. According to claim 1,
And injecting a reducing gas containing hydrogen gas, ammonia gas, or a mixed gas thereof into the reactor. According to claim 1,
And injecting a carrier gas containing an inert gas into the reactor. According to claim 1,
The carbon source is a liquid or gaseous carbon source, carbon nanotube fiber manufacturing method. The method of claim 9,
The liquid or gaseous carbon source is methane, ethylene, acetylene, methylacetylene, vinylacetylene, ethanol, methanol, propanol, acetone, xylene, chloroform, ethylacetic acid, diethyl ether, polyethylene glycol, ethyl formate, mesitylene, tetra Hydrofuran (THF), dimethyl formamide (DMF), dichloromethane, hexane, benzene, toluene, xylene, carbon tetrachloride, and carbon nanotube fiber manufacturing method comprising at least one selected from the group consisting of pentane. According to claim 1,
The method comprising the step of reacting the catalyst, the co-catalyst and the carbon source at a temperature of 1,000 to 3,000 ℃, carbon nanotube fiber manufacturing method. Carbon nanotube fibers produced according to the method of any one of claims 1 to 11.

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