KR102176630B1 - Method for preparing single-walled carbon nanotube fiber - Google Patents

Abstract

The present invention relates to an efficient method for producing single-walled carbon nanotube fibers. According to the manufacturing method, a single-walled carbon nanotube fiber can be easily manufactured by adjusting the ratio in the spinning material, for example, a catalyst activator and a carbon compound to an amount satisfying Equations 1 and 2.

Description

Method for preparing single-walled carbon nanotube fiber {Method for preparing single-walled carbon nanotube fiber}

The present invention relates to an efficient method for producing single-walled carbon nanotube fibers.

Carbon Nanotube (CNT) is a fibrous carbon allotrope in which a hexagonal honeycomb graphene sheet in which one carbon atom is bonded to three other atoms is rolled into a nano-sized diameter. It has an ideal one-dimensional structure with a very large aspect ratio because it is ㎚ and its length ranges from several hundred µm to several ㎜.

In addition, carbon nanotubes are single-walled carbon nanotubes (SWCNTs), double-walled carbon nanotubes (DWNTs), and multi-walled carbon nanotubes (Multi-walled carbon nanotubes), depending on the number of graphite surface layers. It is divided into Wall Carbon Nanotube, MWNT) and Rope Carbon Nanotube, and is divided into zigzag, armchair, and chiral structures according to asymmetry/chirality.

Such carbon nanotubes are macromolecules having unique physical properties depending on their size and shape, and are light because they are hollow and have electrical conductivity as good as copper, thermal conductivity is as good as diamond, and tensile strength is as good as steel. In particular, carbon nanotubes have a high tensile strength of 100 GPa or more and an elastic modulus of 1 TPa or more.

Accordingly, in recent years, studies have been conducted to manufacture and utilize synthetic carbon nanotubes, such as carbon nanotube fibers, which sufficiently express the excellent properties of carbon nanotubes.

However, synthetic carbon nanotubes are short short fibers that do not have direct bonds between the carbon nanotube units constituting them, and when a tensile force is applied, the carbon nanotube units slide together and the fibers are easily broken. Thus, a method of manufacturing a long fiber synthetic carbon nanotube is being studied.

Meanwhile, the strength of the synthetic carbon nanotubes is affected by the length and diameter of the carbon nanotube units and the bonding force between the carbon nanotube units, and to improve the strength, the length of the carbon nanotube units must be long and the diameter must be small. Cohesion must be high. In particular, when the carbon nanotube unit is a single-walled carbon nanotube, the diameter may be small, and the strength of the synthetic carbon nanotube composed of the carbon nanotube may be improved.

Republic of Korea Patent Publication No. 10-2003-0080521

The present invention has been devised to solve the problems of the prior art, and an object of the present invention is to provide an efficient method for producing single-walled carbon nanotube fibers.

In order to solve the above problems, the present invention includes the step of spinning a spinning raw material including a carbon compound in the presence of a carrier gas including a reducing gas using a catalyst system including a catalyst activator and a catalyst precursor, The catalyst activator and the carbon compound are used in an amount satisfying the following Equations 1 and 2 to provide a method for producing a single-walled carbon nanotube fiber.

[Equation 1]

[Equation 2]

In Equations 1 and 2,

A represents the molar ratio of the catalyst activator and the carbon compound [carbon compound/catalyst activator],

IG and ID represent the maximum peak intensity of carbon nanotube fibers measured by Raman spectroscopy, respectively, IG is the maximum peak intensity in the range of vibration frequency 1560 cm ^-1 to 1600 cm ^-1 , and ID is vibration frequency 1310 cm ^It is the maximum peak intensity in the range of ^-1 to 1350 cm ^-1 .

The method for producing a single-walled carbon nanotube fiber according to the present invention easily prepares a single-walled carbon nanotube fiber by adjusting the ratio in the spinning material, for example, a catalyst activator and a carbon compound to an amount satisfying Equations 1 and 2 In this way, it is possible to provide a method of manufacturing a highly reliable single-walled carbon nanotube fiber.

The following drawings attached to the present specification illustrate preferred embodiments of the present invention, and serve to further understand the technical idea of the present invention together with the content of the above-described invention, so the present invention is limited to the matters described in such drawings. It is limited and should not be interpreted.
1 shows the results of Raman spectroscopy analysis of carbon nanotube fibers prepared in Example 1 according to an embodiment of the present invention.
2 shows the Raman spectroscopy analysis results of the carbon nanotube fibers prepared in Example 2 according to an embodiment of the present invention.
3 shows the Raman spectroscopy analysis results of the carbon nanotube fibers prepared in Example 3 according to an embodiment of the present invention.
Figure 4 shows the Raman spectroscopy analysis results of the carbon nanotube fibers prepared in Comparative Example 1 according to an embodiment of the present invention.
5 shows the results of Raman spectroscopy analysis of carbon nanotube fibers prepared in Comparative Example 2 according to an embodiment of the present invention.

Hereinafter, the present invention will be described in more detail to aid understanding of the present invention.

The terms or words used in the specification and claims should not be construed as being limited to a conventional or dictionary meaning, and the inventor may appropriately define the concept of the term in order to describe his own invention as the best invention. It should be interpreted as a meaning and concept consistent with the technical idea of the present invention based on the principle that there is.

The term "carbon nanotube" used in the present invention refers to a fibrous carbon allotrope in which a hexagonal honeycomb graphene sheet in which one carbon atom is bonded to three other atoms is rolled into a nano-sized diameter. To indicate.

The term "single-walled carbon nanotube fiber" used in the present invention is formed by growing the single-walled carbon nanotube aggregate into a fibrous shape using one single-walled carbon nanotube as a unit, or It indicates that a plurality of single-walled carbon nanotube aggregates are fused to form.

The term "unit" used in the present invention refers to a starting material or a raw material in a material containing or derived therefrom.

The term "aggregate" used in the present invention refers to a form in which units are gathered, and includes, for example, a form in which a plurality of units are aggregated, a form in which a plurality of units are connected.

The term "metallocene" used in the present invention refers to a biscyclopentadienyl complex salt composed of two cyclopentadiene rings and various transition metals.

The term "Raman spectroscopy" used in the present invention refers to a spectroscopy method that obtains the frequency of a molecule in the Raman effect. Here, the Raman effect is a powerful monochromatic excitation light such as laser light on a specific molecule. It represents a phenomenon in which scattered light with a difference by the frequency of the molecule occurs when exposed to.

The present invention provides a method for producing single-walled carbon nanotube fibers that can efficiently produce single-walled carbon nanotube fibers composed of single-walled carbon nanotubes through a simple method.

In the method for producing the single-walled carbon nanotube fiber according to an embodiment of the present invention, a single-walled carbon nanotube fiber is easily manufactured by using the ratio in the spinning material, in particular, the catalyst activator and the carbon compound to satisfy specific conditions. can do.

Specifically, the method of manufacturing the single-walled carbon nanotube fiber is a step in which a spinning material containing a carbon compound is spun in the presence of a carrier gas including a reducing gas using a catalyst system including a catalyst activator and a catalyst precursor (step A), wherein the catalyst activator and the carbon compound are used in an amount satisfying the following Equations 1 and 2.

[Equation 1]

[Equation 2]

In Equations 1 and 2,

A is to represent the maximum peak intensity of the catalyst activator and will represent the molar ratio of the carbon compound, a carbon compound / catalyst activator], IG, and ID is the carbon nanotube fibers as measured by Raman spectroscopy, respectively, IG is a vibration frequency of 1560 cm ^{- It} is the maximum peak intensity in the range of ¹ to 1600 cm ^-1 , and ID is the maximum peak intensity in the range of the vibration frequency 1310 cm ^-1 to 1350 cm ^-1 .

Specifically, in Equation 1, A is not limited as long as IG/ID satisfies Equation 2, but, for example, A may be 650 to 7500, specifically 1000 to 3000, more specifically 1200 To 2500.

In an embodiment of the present invention, Equation 1 is a regression equation showing a functional relationship between variables, specifically, a ratio of IG and ID values of carbon nanotube fibers (IG/ID) as a first variable, and catalyst The functional relationship between the first variable and the second variable is shown using the molar ratio of the activator and the carbon compound [carbon compound/catalyst activator] as a second variable.

Here, Equation 1 is recorded by controlling the molar ratio of the catalyst activator and the carbon compound in various ways, and accordingly, a number of carbon nanotube fibers are repeatedly prepared and each of the prepared carbon nanotube fibers is analyzed by Raman spectroscopy. And after recording the ID value, draw a dot graph from the IG/ID value obtained from the IG and ID values of the carbon nanotube fiber and the molar ratio of the catalyst activator and the carbon compound used in the production of these carbon nanotube fibers, and regression therefrom. It was written by finding and testing the equation.

In addition, Equation 2 shows the RBM (radical breathing mode) peak occurring at a vibration frequency of 100 cm ^-1 to 500 cm ^-1 that appears only in single-walled carbon nanotubes by analyzing each prepared carbon nanotube fiber by Raman spectroscopy. After separately recording the IG and ID values for the carbon nanotube fibers, the range of the IG/ID values obtained from these IG and ID values is shown.

Here, the Raman spectroscopy was measured using DXR ^TM 2 Raman Microscope (ThermoFisher Scientific) equipment.

The manufacturing method according to the present invention includes the molar ratio between the catalytic activator and the carbon compound contained in the spinning raw material used for manufacturing the carbon nanotube fiber through a number of repeated experiments as described above, and the IG/ID value of the produced carbon nanotube fiber. By deriving the functional relationship and the range of IG/ID values that appear in the case of single-walled carbon nanotube fibers, and by deriving Equations 1 and 2 as described above, the single-walled carbon nanotube fibers can be efficiently produced in a simple manner. It can be manufactured, and high reliability can be imparted to the fact that single-walled carbon nanotube fibers are manufactured.

The step A is a step for producing a single-walled carbon nanotube fiber from a spinning material containing a catalyst activator and a carbon compound. Using a catalyst system including a catalyst activator and a catalyst precursor, a spinning material containing a carbon compound is It may be performed by radiation in the presence of a carrier gas including a reducing gas. In this case, the catalyst activator and the carbon compound may be used in an amount satisfying Equations 1 and 2.

In one embodiment of the present invention, the carbon compound may be liquid or gaseous as a carbon source, and methane, ethylene, acetylene, methylacetylene, vinylacetylene, ethanol, methanol, propanol, acetone, xylene, chloroform, ethylacetic acid, Diethyl ether, polyethylene glycol, ethyl formate, mesitylene, tetrahydrofuran, dimethylformamide, dichloromethane, hexane, benzene, carbon tetrachloride, and pentane may be one containing at least one selected from the group consisting of.

Specifically, when the carbon compound is in a liquid state, the carbon compound is ethanol, methanol, propanol, acetone, xylene, chloroform, ethyl acetic acid, diethyl ether, polyethylene glycol, ethyl formate, mesitylene, tetrahydrofuran, dimethyl It may contain one or more selected from the group consisting of formamide, dichloromethane, hexane, benzene, carbon tetrachloride, and pentane.

In addition, when the carbon compound is a gas phase, the carbon compound may include one or more selected from the group consisting of methane, ethylene, acetylene, methylacetylene, and vinylacetylene.

More specifically, the carbon compound may be methane.

According to an embodiment of the present invention, the catalytic activator may act as an accelerator for synthesizing carbon nanotubes to increase a carbon diffusion rate so that a carbon nanotube unit is synthesized in a short time. Specifically, in general, the carbon nanotube unit is synthesized as carbon diffuses into the catalyst and then precipitates while the catalyst is molten. In this case, the catalyst activator may play a role of promoting diffusion of the carbon into the catalyst. have.

The catalytic activator is not particularly limited, but specifically, 1 selected from the group consisting of sulfur, methylthiol, methylethylsulfide, dimethylthioketone, phenylthiol, difetylsulfide, pyridine, quinoline, benzothiophene and thiophene. It may contain more than a species. More specifically, the catalytic activator may contain sulfur or thiophene, and more specifically, the catalytic activator may contain sulfur.

The catalyst precursor itself is not included in the catalyst cycle, but is a material constituting the catalyst system. After the catalyst precursor forms the catalyst system, a carbon nanotube unit may be synthesized.

It may be in the form of the metallocene, and specifically, the catalyst precursor may include at least one transition metal selected from the group consisting of iron, nickel, cobalt, platinum, ruthenium, molybdenum, vanadium, and oxides thereof. More specifically, the catalyst precursor may be a metallocene containing at least one transition metal of iron, nickel and cobalt, and more specifically, ferrocene.

Meanwhile, the catalyst precursor may be included in the spinning raw material in an amount of 0.5 to 10 parts by weight based on 100 parts by weight of the carbon compound, specifically 1 to 5 parts by weight or 1.5 to 4 parts by weight. I can. If the catalyst precursor exceeds the above-described maximum amount and is excessively included, it acts as an impurity, and the purity of the single-walled carbon nanotube fiber thus produced may decrease, and thermal, electrical, and physical properties may be deteriorated.

In addition, the catalyst precursor and catalyst activator according to an embodiment of the present invention may have different phases depending on the phase of the carbon compound. For example, when the carbon compound is in a liquid phase, the catalyst precursor and the catalyst activator may be in a liquid phase, and when the carbon compound is in a gas phase, the catalyst precursor and the catalytic activator may also be in a gas phase.

According to an embodiment of the present invention, the reducing gas is not particularly limited, but may be specifically hydrogen, ammonia, or a combination thereof.

In addition, the carrier gas may include an inert gas, and the inert gas may include at least one selected from the group consisting of nitrogen, helium, neon, argon, krypton, xenon, and radon. Here, the inert gas is chemically very stable and has a property that does not exchange or share electrons, and may only perform a role of moving without causing a reaction with the synthesized carbon nanotube.

On the other hand, the spinning according to an embodiment of the present invention is not particularly limited, and may be performed using solution spinning, array spinning, airgel spinning, film twisting/rolling method, etc., and specifically, chemical deposition It may be performed by a process of directly spinning a carbon nanotube aggregate formed from a spinning material by using. That is, the radiation according to an embodiment of the present invention may be specifically performed by direct radiation.

The direct spinning is performed by injecting a spinning material and a carrier gas into a reactor equipped with a reaction zone to synthesize single-walled carbon nanotube units, and fusing the synthesized single-walled carbon nanotube units to form single-walled carbon nanotube aggregates. It can be.

In the reaction zone, single-walled carbon nanotube units are synthesized from a spinning material, and the synthesized single-walled carbon nanotube units are grown or fused to continuously aggregate to form a single-walled carbon nanotube aggregate, and finally, single-walled carbon nanotubes. As a region in which the tube fibers are formed, it may have a high temperature atmosphere of 1,000°C to 3,000°C. Specifically, the reaction zone may have a high temperature atmosphere of 1,000°C to 2,000°C, more specifically 1,000°C to 1,500°C, or 1,000°C to 1,300°C. If the reaction zone is less than 1,000°C, the single-walled carbon nanotube unit may not be synthesized, and if it exceeds 3,000°C, the synthesized single-walled carbon nanotube unit may be vaporized.

Meanwhile, the spinning material may be a catalyst activator, a carbon compound, and a catalyst precursor contained therein are mixed in advance and injected in the form of a mixture, or a catalyst activator, a carbon compound, and a catalyst precursor are separated into a reactor and injected simultaneously.

At this time, when the spinning material is injected in the form of a mixture, the catalyst activator and the carbon compound may be included in the mixture in a ratio satisfying the conditions as described above, and the spinning material is 50 ml/min to 200 It may be injected into the reactor at a flow rate of ml/min.

In addition, when the catalyst activator, the carbon compound, and the catalyst precursor are separated from the spinning raw material and simultaneously injected into the reactor, the carbon compound may be injected into the reactor at a flow rate of 10 ml/min to 500 ml/min. For example, it may be injected into the reactor at a flow rate of 50 ml/min to 200 ml/min or 80 cm ³ /min to 150 cm ³ /min. In this case, the catalytic activator may be controlled and injected according to the flow rate of the carbon compound so as to satisfy the conditions as described above.

In addition, the carrier gas may be injected into the reactor at a flow rate of 1 L/min to 5 L/min, and specifically, may be injected into the reactor at a flow rate of 1.5 L/min to 3 L/min.

Thereafter, the synthesized single-walled carbon nanotube fibers can be collected by winding, and the winding speed at this time affects the cultivation of the single-walled carbon nanotubes in the fiber in the fiber axis direction, resulting in single-walled carbon nanotubes. It can affect the thermal, electrical and physical properties of the fiber. Therefore, in order to minimize the effect on the single-walled carbon nanotube fiber during the winding, the winding speed may be 1 m/min to 1000 m/min.

Hereinafter, the present invention will be described in more detail through examples. However, the following examples are for illustrative purposes only, and the scope of the present invention is not limited thereto.

Examples 1 to 3

As shown in Table 1 below, single-walled carbon nanotube fibers were prepared by differently controlling the molar ratio of methane and sulfur.

Specifically, ferrocene was vaporized at the top of a cylindrical reactor equipped with a high-temperature heating furnace at 1200° C. at 60 mg/hr, sulfur at 1.5 to 5 mg/hr, and injected, methane was 80 to 120 ml/min, and hydrogen was 1.3 L. The carbon nanotubes were synthesized by injecting at /min, and the single-walled carbon nanotube fibers discharged through the lower outlet of the reactor were wound with a winding means composed of a bobbin.

Comparative Example 1 and Comparative Example 2

As shown in Table 1 below, carbon nanotube fibers were prepared by differently controlling the molar ratio of methane and sulfur.

Specifically, ferrocene was vaporized at 60 mg/hr and sulfur at 6-12 mg/hr and injected into the top of a cylindrical reactor equipped with a high-temperature heating furnace at 1200° C., methane was 100 ml/min, and hydrogen was 1.3 L/min. The carbon nanotubes were synthesized by injecting into the reactor, and the carbon nanotube fibers discharged through the lower outlet of the reactor were wound with a winding means composed of a bobbin.

division Methane/sulfur molar ratio Example 1 1284 Example 2 1508 Example 3 2492 Comparative Example 1 311 Comparative Example 2 623

Experimental example

Raman spectroscopy analysis was performed on each of the single-walled carbon nanotube fibers prepared in Examples 1 to 3 and each of the carbon nanotube fibers prepared in Comparative Examples 1 and 2. At this time, the Raman analysis method was performed using a DXR ^TM 2 Raman Microscope (ThermoFisher Scientific) equipment, and the analysis results are shown in FIGS. 1 to 5.

In addition, from each analysis result, the maximum peak intensity IG in the range of 1560 cm ^-1 to 1600 cm ^-1 and the maximum peak intensity ID in the range of 1310 cm ^-1 to 1350 cm ^-1 were derived, respectively, and the ratio of IG and ID ( IG/ID) was calculated and shown in Table 2 below.

division IG/ID Calculated value Measures Example 1 8.7 10.41 Example 2 9.90 9.99 Example 3 15.13 14.53 Comparative Example 1 3.53 3.81 Comparative Example 2 5.19 3.72

In Table 2, the calculated value is a value calculated by substituting the molar ratio of sulfur and methane described in Table 1 to A through Equation 1 of the present invention, and the measured value is a value obtained by analyzing by the Raman spectroscopy method.

As shown in Table 2, it was confirmed that the calculated IG/ID value and the measured value were similar, and through this, it was confirmed that the suitability of Equation 1 of the present invention is high.

In addition, as shown in FIGS. 1 to 5, Examples 1 to 3 in which the amounts of sulfur as a catalyst activator and methane as a carbon compound were adjusted to satisfy Equations 1 and 2 according to an exemplary embodiment of the present invention. The carbon nanotube fiber prepared in was observed at a vibration frequency (Raman shift) [150 cm ^-1 to 250 cm ^{- 1} ]. On the other hand, in the case of the carbon nanotube fibers prepared in Comparative Examples 1 and 2, no specific peak was observed at the vibration frequency. On the other hand, the RBM (radical breathing mode) peak occurring at a vibration frequency of 100 cm ^-1 to 500 cm ^-1 is known as a characteristic appearing in single-walled carbon nanotubes (Journal of the KSME, Vol. 55, No. 12, pp32). ~35, Sungkyunkwan University, Baek Seunghyun).

Through this, according to the manufacturing method according to an embodiment of the present invention, the molar ratio of the catalytic activator and the carbon compound at the time of manufacturing the carbon nanotube is determined by using the IG and ID values of the single-walled carbon nanotube fiber. Single-walled carbon nanotube fibers can be easily manufactured by adjusting the ratio to have the IG and ID values of the nanotube fibers, and furthermore, when carbon nanotubes are manufactured by applying the above molar ratio, single-walled carbon nanotube fibers It can be seen that it can be manufactured with high reliability.

Claims (13)

Using a catalyst system including a catalyst activator and a catalyst precursor, a spinning raw material containing a carbon compound is spinning in the presence of a carrier gas including a reducing gas,
The catalytic activator and the carbon compound are used in an amount satisfying the following Equation 1 and Equation 2, the method of producing a single-walled carbon nanotube fiber:
[Equation 1]

[Equation 2]

In Equations 1 and 2,
A represents the molar ratio of the catalyst activator and the carbon compound [carbon compound/catalyst activator],
IG and ID represent the maximum peak intensity of carbon nanotube fibers measured by Raman spectroscopy, respectively, where IG is the maximum peak intensity in the range of vibration frequency 1560 cm ^-1 to 1600 cm ^-1 , and ID is vibration frequency 1310 cm ^Is the maximum peak intensity in the range of ^-1 to 1350 cm ^-1 ,
A is 630 to 7500.
delete The method according to claim 1,
In Equation 1, A is a method for producing a single-walled carbon nanotube fiber that is 1200 to 2500.
The method according to claim 1,
The carbon compound is liquid or gaseous,
Methane, ethylene, acetylene, methylacetylene, vinylacetylene, ethanol, methanol, propanol, acetone, xylene, chloroform, ethylacetic acid, diethyl ether, polyethylene glycol, ethylformate, mesitylene, tetrahydrofuran, dimethylformamide, Dichloromethane, hexane, benzene, carbon tetrachloride, and a method for producing a single-walled carbon nanotube fiber comprising at least one selected from the group consisting of pentane.
The method according to claim 1,
The catalytic activator is a single wall containing at least one selected from the group consisting of sulfur, methylthiol, methylethylsulfide, dimethylthioketone, phenylthiol, difetylsulfide, pyridine, quinoline, benzothiophene and thiophene Method for producing carbon nanotube fibers.
The method according to claim 1,
The catalyst precursor is a method of producing a single-walled carbon nanotube fiber in the form of a metallocene.
The method of claim 6,
The catalyst precursor is iron, nickel, cobalt, platinum, ruthenium, molybdenum, vanadium, and a method of producing a single-walled carbon nanotube fiber comprising at least one transition metal selected from the group consisting of oxides thereof.
The method according to claim 1,
The reducing gas is a method of producing a single-walled carbon nanotube fiber containing hydrogen, ammonia or a mixture gas thereof.
The method according to claim 1,
The method for producing a single-walled carbon nanotube fiber wherein the carrier gas contains an inert gas.
The method of claim 9,
The inert gas is a method of producing a single-walled carbon nanotube fiber containing at least one selected from the group consisting of nitrogen, helium, neon, argon, krypton, xenon and radon.
The method according to claim 1,
The method of manufacturing a single-walled carbon nanotube fiber, wherein the spinning is performed by direct spinning.
The method of claim 11,
The direct spinning is a method of producing a single-walled carbon nanotube fiber by injecting a spinning material and a carrier gas into a reactor having a reaction zone to synthesize carbon nanotubes, and fusing the synthesized carbon nanotubes.
The method of claim 12,
The reaction zone is a method of producing a single-walled carbon nanotube fiber having a high temperature atmosphere of 1,000 ℃ to 3,000 ℃.

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