KR101972843B1 - Method for Preparing poly(2-cyano-p-phenylene terephthalamide) Nano-fibers and Carbon Nano-fibers Derived Therefrom - Google Patents

Abstract

The present invention discloses a method and system for producing poly (2-cyano-p-phenylene terephthalamide) nanofibers having improved physical properties by electrospinning using multiple spinnerets, and using the same as a precursor to produce high quality A method and system for producing carbon nanofibers are described.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for preparing a poly (2-cyano-p-phenylene terephthalamide) nanofiber and a carbon nanofiber derived therefrom Derived Therefrom}

This disclosure relates to the preparation of poly (2-cyano-p-phenylene terephthalamide) nanofibers and carbon nanofibers derived therefrom. More particularly, the present disclosure relates to a method and system for making poly (2-cyano-p-phenylene terephthalamide) nanofibers having improved physical properties by electrospinning using multiple spinnerets, To a method and system for producing high quality carbon nanofibers.

Aromatic polyamide (aromatic polyamide) material of poly (p- phenylene terephthalamide) (poly (p-phenylene terephthalamide ; PPTA) fibers, a high-performance aramid fibers, trade name Kevlar ^ㄾ (EI DuPont Co.) and Twaron ^ㄾ (Teijin Aramid yarn PPTA is a homopolymer having a repeating unit derived from the polymerization reaction of p-phenylenediamine and terephthaloyl chloride as shown in the following general formula (1), further, a copolymer containing another diamine or diacid chloride to be.

[Formula 1]

Typically, PPTA is classified into a meta-type having a flexible bendability and a para-type having a rigid bar structure depending on the structural characteristics of a molecular chain. The double para type polyamide exhibits excellent thermal properties (for example, heat resistance, flame retardancy, etc.) and mechanical properties (for example, tensile strength and elastic modulus) and low density characteristics. Specifically, the aramid exhibits a tensile strength of 20 g / d or more and a tensile modulus of 500 to 1,300 g / d, and exhibits excellent cold resistance, insulation, and chemical resistance to maintain fiber properties even at a low temperature of -160 ° C. Therefore, it is replacing metal wire or inorganic fiber in the high performance fiber market. Recently, it has been attracting much attention as a new material of high-tech industry, such as being applied to a gas filter material requiring excellent chemical resistance.

PPTA fibers are generally prepared by dissolving PPTA in sulfuric acid at a high temperature of 100% to prepare a liquid crystal polymer solution, which is then subjected to a dry / wet process Can be produced by spinning. Recently, a technique of filing a polymer solution in which PPTA is dissolved in a solvent by electrospinning is also known (Korean Patent No. 1260529, Japanese Patent No. 5102631, Japanese Patent No. 0549140, etc.).

However, PPTA has low solubility in polar organic solvents such as N-methylpyrrolidone (NMP), N, N-dimethylacetamide (DMAc) and the like due to strong hydrogen bonding between amide groups and inter-chain π- , And solubility only for some strong acids such as sulfuric acid. Therefore, when the fiber is dissolved in an organic solvent to prepare the fiber by electrospinning, continuous production is difficult, and the electrospinning device occludes occasionally. Therefore, the solubility is increased mainly by the use of strong acid, and in this case, corrosion of the spinning apparatus is induced, and the recovery cost of the solvent is increased, and also environmental pollution problem due to strong acid is caused.

As described above, due to the low solubility of PPTA in an organic solvent, it is difficult to produce nanofibers on a commercial scale, and there is also a limit in improvement of physical properties.

Attempts have been made to introduce various polar substituents (e.g., halogens, nitro groups, etc.) at the ortho or meta positions of the benzene ring in the PPTA structure to improve low solubility in organic solvents, which is a disadvantage of PPTA. The introduction of a polar substituent is an attempt to increase the solubility of the polar organic solvent (NMP, DMAc, DMF, and the like) because of its increased electrical coupling strength, but it is difficult to obtain a polymer having a high molecular weight and the fiber strength is lowered.

As a solution to this problem, poly (2-cyano-p-phenylene terephthalamide (PPAR)), which is an aramid polymer substituted with a cyano group at the ortho position of the aromatic ring of PPTA, CY-PPTA) in a polar organic solvent containing a metal salt such as LiCl (U.S. Patent No. 5,728,799). Despite the substitution of bulky cyano groups, a technique of spinning in a lyotropic state The tensile strength and modulus of the CY-PPTA fibers are comparable to those of aramid fibers.

As described above, in the case of the technique of manufacturing the CY-PPTA nanofiber by the electrospinning method which is widely used in the production of the PPTA fiber, although the solubility in the polar organic solvent can be improved considerably, It is difficult to produce, and in particular, a bead-shaped cohesive region which is not fibrous is formed on the CY-PPTA nanofibers collected or collected by spinning. Therefore, since it causes defects in nonwoven fabric made of CY-PPTA nanofiber, it is limited in a specific field. Furthermore, the strength and elongation properties (e.g., elongation) of the fibers tend to be opposite to each other, and it is desirable to simultaneously improve such mutually conflicting properties.

On the other hand, carbon nanofibers mean fibrous materials having a fine thickness including carbon of 90% or more, and their application fields are different according to their shapes and microstructures. Because the basic properties of the carbon element form a bond by sp, sp2 or sp3 hybridization when forming the material, it exhibits high strength, good electrical and thermal conductivity such as graphite, and chemically stable and biocompatible properties. The specific surface area increases when the material having such a structural characteristic is converted to nanofiber, and the adsorption property is exhibited when the pore is formed. Therefore, the present invention can be applied to a catalyst support, an adsorbent, and the like.

In this connection, there has been developed a technique for producing carbon nanofibers through carbonization or stabilization-carbonization using nanofibers prepared from polyimide, polyacrylonitrile, pitch or the like as a carbon precursor (WO2011 / 089754 , Korean Patent No. 0605006, Korean Patent Publication No. 2008-0043856, etc.).

As the basic structure of the carbon nanofiber is changed according to the carbon precursor and the physical properties thereof are changed, it is preferable that the precursor nanofiber should have good physical properties and exhibit high productivity in the production of carbon nanofibers. However, when using a conventional carbon precursor, it may be required to go through a stabilization step for a considerable time prior to the carbonization step after the production of the precursor fiber. Further, even when a precursor of CY-PPTA fiber is used, there is still a limit in producing a fiber of uniform thickness in the spinning (electrospinning) process, and there is a bead-like aggregation (or aggregation) region, The carbon nanofibers also have problems inherent in the precursor nanofibers.

Therefore, it is possible to produce high-quality carbon nanofibers by using CY-PPTA, which exhibits physical properties equal to or higher than those of conventional PPTA, and has good solubility in an organic solvent, as well as producing nanofibers of good properties and further using them as precursors There is a need for technology.

Accordingly, in one embodiment of the present disclosure, a method of manufacturing a CY-PPTA nanofiber using an electrospinning method, the CY-PPTA nanofiber having uniform thickness and effectively suppressing the formation of a coagulation region in the final nanofiber, PPTA nanofibers and improved properties of CY-PPTA nanofibers as carbon precursors to produce carbon nanofibers of improved physical properties.

In another embodiment of the present disclosure, an electrospinning system and carbon nanofiber manufacturing system for producing CY-PPTA nanofibers having improved properties are provided.

According to a first aspect of the present disclosure,

Providing a multi-spinnerette having an inner spinneret in an outward direction from the center, an intermediate spinneret surrounding the inner spinneret, and an outer spinneret surrounding the intermediate spinneret;

A mixed solution obtained by dissolving a polymer and a metal salt containing CY-PPTA in an organic solvent is supplied to the inner spinneret, an organic solvent is supplied to the intermediate spinneret, and a gas is supplied to the outer spinneret and simultaneously electrospun. ; And

Recovering the nanofibers;

A method of producing a CY-PPTA nanofiber comprising the steps of:

According to a second aspect of the present disclosure,

A mixed solution supply part for supplying a polymer spinning solution in which a polymer including CY-PPTA and a metal salt are dissolved in an organic solvent;

An organic solvent supply unit for supplying an organic solvent;

A gas supply unit;

Wherein the inner radiation hole, the intermediate radiation hole, and the outer radiation hole each have an inner radiation hole, an intermediate radiation hole, and an outer radiation hole in the outward direction from the center, and each of the inner radiation hole, Spinning gates;

A collector disposed opposite the multiple emitter and collecting or accumulating CY-PPTA nanofibers emitted from the emitter; And

A voltage generator for supplying a voltage to the plurality of emitters and the collector;

Wherein the CY-PPTA nanofibers are produced by a method comprising the steps of:

According to an exemplary embodiment, the feed rate of the mixed solution supplied to the inner spinneret is 1 to 10 ml / h, the feed rate of the organic solvent supplied to the intermediate spinneret is 1 to 8 ml / h, The sphere may be supplied with a gas at a pressure of 0.1 to 0.5 bar.

According to an exemplary embodiment, the inner diameter of the inner aperture may be in the range of 0.4 to 1.2 mm, the inner diameter of the intermediate aperture may be in the range of 0.8 to 1.5 mm, and the inner diameter of the outer aperture may be in the range of 1.5 to 20 mm.

According to an exemplary embodiment, the voltage applied during the electrospinning may range from 12 to 35 kV.

According to a third aspect of the present disclosure,

Providing a multi-spinnerette having an inner spinneret in an outward direction from the center, an intermediate spinneret surrounding the inner spinneret, and an outer spinneret surrounding the intermediate spinneret;

A mixed solution obtained by dissolving a polymer and a metal salt containing CY-PPTA in an organic solvent is supplied to the inner spinneret, an organic solvent is supplied to the intermediate spinneret, and a gas is supplied to the outer spinneret and simultaneously electrospun, Forming a PPTA-based nanofiber;

Carbonizing the nanofibers to convert them into carbon nanofibers; And

Recovering the carbon nanofibers;

Wherein the carbon nanofibers of the carbon nanofibers obtained from the CY-PPTA are produced by a method comprising the steps of:

According to a fourth aspect of the present disclosure,

A mixed solution supply part supplying a polymer solution containing CY-PPTA and a polymer solution obtained by dissolving a metal salt in an organic solvent;

An organic solvent supply unit for supplying an organic solvent;

A gas supply unit;

Wherein the inner radiation hole, the intermediate radiation hole, and the outer radiation hole each have an inner radiation hole, an intermediate radiation hole, and an outer radiation hole in the outward direction from the center, and each of the inner radiation hole, Spinning gates;

A voltage generator for supplying a voltage to the plurality of radiation sources;

A collector disposed opposite the multiple emitter and collecting or accumulating CY-PPTA nanofibers emitted from the emitter; And

A heat treatment apparatus for carbonizing the collected or integrated CY-PPTA nanofibers;

Wherein the carbon nanofibers are produced by a method comprising:

According to an exemplary embodiment, the method for producing carbon nanofibers may further include a stabilization step prior to the carbonization step, and the stabilization step may be performed at a temperature ranging from 180 to 300 ° C.

The method and system according to embodiments of the present disclosure use multiple spinnerets formed with an inner spinneret, an intermediate spinneret, and an outer spinneret from the center outward (e.g., concentrically) CY-PPTA nanofibers having a uniform thickness are produced at a high production rate by effectively suppressing the solidification phenomenon of the mixed solution by supplying the organic solvent to the intermediate yarn, supplying the organic solvent to the intermediate yarn, and supplying the gas to the outside yarn. And it is also possible to produce high quality CY-PPTA nanofibers in which aggregation is suppressed in the produced nanofibers.

Also, the carbon nanofibers prepared using the CY-PPTA nanofibers prepared according to the specific embodiments of the present disclosure exhibit excellent physical properties, and thus can be applied to various applications such as an ebony electron material, a catalyst support, and a gas adsorbent.

Therefore, wide commercialization is expected in the future.

1 is a schematic diagram of an electrospinning system for producing CY-PPTA nanofibers according to one embodiment;
FIG. 2 is a view showing a process of electrospinning CY-PPTA nanofibers using triple sheaths according to an exemplary embodiment; FIG.
3 is a process flow chart schematically showing a series of processes for producing carbon nanofibers according to one embodiment;
4 is an optical micrograph (x 100) of the CY-PPTA nanofibers prepared according to Example 1;
5 is a scanning electron microscope (SEM) photograph (× 1000) of the CY-PPTA nanofibers prepared according to Example 1;
6 is a scanning electron microscope (SEM) photograph (× 1000) of the CY-PPTA nanofibers prepared according to Example 2;
7 is an optical microscope photograph (x 100) of the CY-PPTA nanofiber prepared according to Comparative Example 1;
8 is a scanning electron microscope (SEM) photograph (× 5000) of carbon nanofibers derived from CY-PPTA prepared according to Example 5;
9 is a scanning electron microscope (SEM) photograph (× 5000) of carbon nanofibers derived from CY-PPTA prepared according to Example 9; And
Fig. 10 is a graph showing the results of a stabilized carbon fiber nonwoven fabrics fabricated through (i) electrospun nanofiber nonwoven fabric, (ii) stabilized nanofiber nonwoven fabric, (iii) carbonized carbon nanofiber nonwoven fabric, and (iv) Optical micrograph (× 100) of the nanofiber nonwoven fabric.

The present invention can be all accomplished by the following description. The following description should be understood to describe preferred embodiments of the present invention, but the present invention is not necessarily limited thereto. It is to be understood that the accompanying drawings are included to provide a further understanding of the invention and are not intended to limit the scope of the invention.

The terms used in this specification can be defined as follows.

As used herein, the term " nanofiber " means a fiber having nanoscale fine diameter or diameter in a narrow sense, but it can be understood as a concept including fibers having a thickness of several μm or less, specifically, 5 μm or less . Such nanofibers can be prepared by, for example, melt-blown spinning, conjugate spinning, electrospinning, and the like.

&Quot; Electrospinning " may refer to a method of continuously producing nanofibers or webs of several tens of nanometers in diameter from a few micrometers by applying a high voltage to a polymer solution or melt. The principle of the electrospinning process is that electrostatic repulsive force is generated on the surface of the polymer solution when an electric field is applied to the polymer solution, and as the electrostatic repulsion increases, the polymer solution is stretched from the end of the spinneret (or nozzle) A conical droplet shape, called a cone (Taylor cone), is then formed, which is then explained by the fact that if the electric field strength overcomes the surface tension of the polymer solution, the solution is radiated from the nozzle into a fiber form and collected or integrated into a collector .

&Quot; Heat treatment " means treating the entire object or a portion thereof intentionally with a thermal cycle (which may include the case of a change in temperature over time) and, if desired, ) ≪ / RTI > to achieve the desired effect.

&Quot; Carbonization " can generally refer to any heat treatment process that increases the carbon / hydrogen ratio of the solids, and may specifically refer to a process that converts a carbon-containing component to carbon.

The terms " on " and " on " can be understood to be used to refer to the relative position concept. Thus, there may be intervening or present at least one other component or additional component therebetween, as well as where other components are directly present in the mentioned layer. Similarly, the expressions "under", "under" and "under" and "between" may also be understood as relative concepts of position.

Whenever an element or element is described as being "connected" or "communicating" with another element or element, it is understood that the element is not only directly connected or in communication with the other element or element, , Or in the case of being connected or communicated under the interposition of another component or member.

When " comprising " includes any element, it is understood that it may include other elements and / or steps, unless the context requires otherwise.

Figure 1 schematically illustrates an electrospinning system for producing CY-PPTA nanofibers according to one embodiment.

Referring to the drawings, the electrospinning system 10 can be roughly composed of a radiation part, a voltage applying part and a collecting part. At this time, the spinning unit includes the mixed solution supply unit 12, the organic solvent supply unit 13, and the gas supply unit 14. The multiple spinnerets 11 are connected to or connected to the mixed solution supply unit 12, the solvent supply unit 13, and the gas supply unit 14, respectively, as means for spinning the nanofibers using the three fluids. The principle of formation of nanofibers from such an electrospinning system is as follows.

The electrospinning process can be roughly divided into a step of forming a jet, a step of stretching, and a step of solidifying into a nanofiber in a jet. At this time, the charged radiating material is discharged (radiated) to the air through a spinneret (or a spinning nozzle) between two electrodes having opposite polarities, one of which is located at the spinning nozzle and the other is located at the collector. , The charged filament can be stretched in air or the filamentary branch can be made to produce microfine fibers.

More specifically, a positive or negative voltage is directly applied to the spinneret or spinneret to charge the solution, the charged solution is discharged through the spinneret (multiple spinnerets) into the air layer, The nanofibers can be produced through stretching of the charged filament and another filament branch in the air layer. (-) charged filament through the application of (+) voltage to the filament, or (-) the filament charged to the negative filament through the application of voltage to the filament, It can be miniaturized due to electrical influences such as repulsion. The microfilament thus formed can be manufactured in the form of a web integrated on a charged collector with a polarity opposite to that of the grounded collector or charged filament.

- Mixed solution

The mixed solution supply unit 12 supplies a mixed solution obtained by dissolving a polymer including CY-PPTA and a metal salt in an organic solvent to the multiple spinnerets 11. [ At this time, CY-PPTA has a repeating unit represented by the following general formula (2).

[Formula 2]

According to an illustrative embodiment, the ratio of CY-PPTA as a polymer in the mixed solution to the para-position of the aromatic ring in the amide bond is at least about 60%, specifically at least about 80%, more specifically at least To about 90%, and in particular substantially all of the amide bonds may be attached to the para-position of the aromatic ring (i.e., pure CY-PPTA).

The polymer in the mixed solution, particularly CY-PPTA, has an intrinsic viscosity molecular weight of, for example, about 2 to 10 dl / g, specifically about 3 to 7 dl / g, more specifically about 4 to 6 dl / g When the molecular weight is too high or low, it may be advantageous to use a polymer selected within the above-mentioned molecular weight range, because it is difficult to smoothly emit electrons or it may be difficult to obtain nanofibers of desired physical properties.

According to an exemplary embodiment, the concentration of the polymer comprising CY-PPTA in the mixed solution is from about 9 to 25% by weight, specifically from about 10 to 23% by weight, more specifically from about 12 to < RTI ID = 20% by weight. If the content of the polymer is too low, it is difficult to form the nanofiber structure. On the other hand, if the content of the polymer is too high, it may be difficult to produce nanofibers having a uniform diameter. However, the content of the polymer in the mixed solution is not necessarily limited to the above-described range, as it can vary depending on the molecular weight of the CY-PPTA, the solvent, and the like.

In one embodiment, the spinning mixture solution may comprise a metal salt. Such a metal salt functions to improve the solubility of CY-PPTA in an organic solvent, and may be an alkali metal halide salt and / or an alkaline earth metal halide salt. According to an exemplary embodiment, the metal salt may be selected from at least one of CaCl ₂ , LiCl, NaCl, KCl, LiBr, KBr, and the like, and specifically may be CaCl ₂ , LiCl, or a combination thereof.

In this regard, the content of the metal salt in the mixed solution may range, for example, from about 0.5 to 10% by weight, specifically about 1 to 7% by weight, more specifically about 2 to 5% by weight, based on the organic solvent. When the content of the metal salt is excessively low or high, it may be advantageous to appropriately control the liquid crystal phase within the above-mentioned range as the liquid crystal phase may become unstable or the electrical conductivity may change rapidly during the spinning process. Can be understood.

Examples of the organic solvent include dimethylene fluoride, tetramethylene fluoride, benzylaldehyde, ethyl acetate, acetone, acetonitrile, acetaldehyde, acetic acid, But are not limited to, acetophenone, acetyl chloride, acrylonitrile, benzyl alcohol, 1-butanol, n-butyl acetate, cyclohexanol, cyclohexanone, 1,2-dibromoethane, diethyl ketone, , N, N-dimethylformamide, dimethylsulfoxide, 1,4-dioxane, ethanol, ethyl formate, formic acid, glycerol, hexamethylphosphoramide, methyl acetate, methyl ethyl ketone, methyl isobutyl ketone, 2-pyrrolidone, nitrobenzene, nitromethane, 1-propanol, propylene-1,2-carbonate, tetrahydrofuran, tetramethylurea, triethylphosphate, trimethylphosphine Sites, ethylene diamine, and the like may NMMO (N-methylmorpholine N-oxide), may be used either individually or in combination of two or more them.

More specifically, at least one selected from the group consisting of N, N-dimethylacetamide, N-methyl-2-pyrrolidone, hexamethylphosphoramide, and tetramethylurea can be selected as the organic solvent.

According to an illustrative embodiment, the viscosity (25 占 폚) of the electrospinning mixed solution described above is in the range of, for example, about 10 to 100,000 cps, specifically about 100 to 50,000 cps, more specifically about 1,000 to 5,000 cps And since the electrospinning step may be carried out over a long period of time in some cases, it is desirable to form a stable polymer-solvent system as far as possible, as appropriate viscosity needs to be maintained constantly.

The spinning mixture solution is supplied to the multiple spinnerets (11) through the mixed solution supply part (12). The most remarkable point in the embodiment of the present disclosure is that the organic solvent is separately supplied in addition to the spray polymer solution in the electrospinning process. To this end, a separate organic solvent supply unit 13 is provided in addition to the above-mentioned mixed solution, from which the organic solvent is supplied to the multiple emission ports 11. At this time, as the organic solvent of the organic solvent supplier 13, a homologous solvent or a heterogeneous solvent may be used within the range of the solvent used for the preparation of the mixed solution. However, when a homogeneous solvent is used, it may be more effective to suppress the formation of nanofibers having uneven thickness by the solidification phenomenon of the CY-PPTA polymer during the electrospinning process.

 On the other hand, in one embodiment, an arbitrarily heatable or coolable gas (specifically, a compressed gas) is supplied from the gas supply unit 14 to the multiple radiation apertures 11 to advance the polymer flow injected from the mixed solution . Such gas may be, for example, air or an inert gas (e. G., Helium, nitrogen, argon, etc.) that is supplied in a pressurized state, and may typically be air. In addition, the gas supplied to the multiple spinnerets 11 can not only induce the mixed solution to flow in the direction of the collector, but also contribute to the stretching of the fibers emitted from the multiple spinnerets 11. In this regard, the temperature of the gas may affect the viscosity of the spinning solution in the spinning process, for example within the range of about 0 to 120 ° C, specifically about 15 to 90 ° C, more specifically about 25 to 60 ° C Lt; / RTI >

Although not shown separately in FIG. 1, it may further include a pump or a valve capable of controlling the flow rate of each of the mixed solution, the organic solvent, and the gas. Optionally, a gas flow meter 15 such as a pressure gauge for adjusting the flow of gas at the front end of the multiple radiating apertures 11 may be further provided.

Further, in the CY-PPTA nanofiber manufacturing system 10 according to one embodiment, the collector 17 collects or accumulates the radiated CY-PPTA nanofibers arranged opposite to the multiple spinnerets 11. At this time, since the collector 17 is electrically connected to the voltage generating unit 16 of the voltage application unit, the collector 17 may be a metal collector or a collector formed with a metal coating and may be grounded. In addition, the collector 17 may be of a rotating type, and nanofibers or webs collected or integrated on the collector as the rotation progresses may be stacked or wound and recovered. According to an alternative embodiment, the nanofibers collected or integrated by the collector 17 may be transferred and recovered onto a moving conveyor belt (not shown).

According to the exemplary embodiment, the distance between the tip of the nozzle provided in the multiple spinnerets 11, specifically the multiple spinnerets, and the collector 17 is a factor affecting the physical properties of the CY-PPTA nanofibers, For example, from about 5 to 150 cm, specifically from about 8 to 50 cm, and more specifically from about 10 to 25 cm. In addition, the nozzles provided in the multiple spinnerets 11 may be specifically syringe type nozzles.

On the other hand, in the exemplary embodiment, the voltage applied to the multiple radiation apertures 11 by the voltage generator 16 during the electrospinning process is, for example, about 10 to 50 kV, specifically about 12 to 35 kV, More specifically from about 15 to 30 kV.

In addition, the temperature in the section in which the electrospinning is performed, specifically the interval between the multiple radiating apertures 11 and the collector 17, is set to, for example, about 0 to 120 DEG C, specifically about 15 to 90 DEG C, 25 ° C to 60 ° C. If the temperature in the spinning zone is excessively low or high, problems such as unevenness of jet formation and gelation of the spinning solution due to increase in surface tension may be caused. Therefore, It may be advantageous to maintain the range. It should be understood, however, that the above numerical ranges are set forth for illustrative purposes only.

FIG. 2 illustrates a process of electrospinning CY-PPTA nanofibers using a triple spinnerette according to an exemplary embodiment.

According to the illustrated embodiment, the multiple radiation apertures 11 consist of triple radiation apertures 20. The triple radiation hole 20 includes an inner radiation hole 21, an intermediate radiation hole 22 and an outer radiation hole 23 in the outer direction from the center thereof. The inner radiation hole 21, Each of the outer and inner spinnerets 22 and 23 may be connected to or connected to the mixed solution supply unit 12, the organic solvent supply unit 13, and the gas supply unit 14 indicated in FIG.

Illustratively, the inner radiation hole 21, the intermediate radiation hole 22, and the outer radiation hole 23, which constitute the triple radiation hole 20, may form a concentric structure, alternatively, . ≪ / RTI >

As described above, by using the triple radiation hole 20, the flow of the CY-PPDA-containing mixed solution through the inner radiation hole 21 in the electrospinning process is conducted through the intermediate radiation hole 22 formed on the outer side thereof, It is possible to suppress the solidification phenomenon of the radiated fibers by contacting with the flow of the solvent in a surrounding manner. In addition, since the organic solvent is easily evaporated and removed at a relatively mild temperature (even at room temperature) without a separate post-treatment, the manufacturing process of the CY-PPTA nanofibers can be simplified and the manufacturing cost can be reduced.

In the exemplary embodiment, the exemplary sizes of the inner radiation hole 21, the intermediate radiation hole 22, and the outer radiation hole 23 constituting the triple radiation hole 20 can be set as follows.

(i) the inner diameter of the inner spinneret: about 0.3 to 1.5 mm, specifically about 0.4 to 1.2 mm, more specifically about 0.5 to 1 mm,

(ii) an inner diameter of the intermediate spinneret: about 0.5 to 1.8 mm, about 0.8 to 1.6 mm, more specifically about 0.9 to 1.4 mm, and

(iii) the inner diameter of the outer spinneret: about 1 to 25 mm, specifically about 1.5 to 20 mm, more specifically about 1.8 to 15 mm.

According to an exemplary embodiment of the present disclosure, the feed rate of the mixed solution supplied through the inner radiation port 21 is, for example, about 0.8 to 12 ml / h, specifically about 1 to 10 ml / h, Specifically about 1.5 to 8 ml / h. The supply rate of the organic solvent through the intermediate spinneret 22 is, for example, in the range of about 0.7 to 10 ml / h, specifically about 1 to 8 ml / h, more specifically about 1.2 to 6 ml / h . In addition, the gas supplied through the outer spinneret can be supplied at a pressure of, for example, about 0.05 to 1 bar, specifically about 0.1 to 0.5 bar, more specifically about 0.2 to 0.45 bar.

When the flow of the mixed solution, the organic solvent, and the gas supplied in the triple spinnerette 20 is controlled, the CY-PPTA nanofibers are prevented from solidifying from the mixed solution before the CY-PPTA nanofibers are formed, -PPTA-based nanofibers (specifically, crystalline, more specifically, CY-PPTA nanofibers showing liquid crystal behavior) are uniformly formed, and furthermore, the clogging of the spinneret nozzle due to pre-solidification of the mixed solution is suppressed The production rate of the CY-PPTA nanofibers can be more effectively increased.

The electrospun CY-PPTA nanofibers using the system described above may have a microdiameter up to the micrometer level, for example from about 5 nm to about 7 μm, specifically from about 10 nm to about 5 μm Specifically, it may have a diameter or a thickness ranging from about 500 nm to 3 占 퐉. In certain embodiments, the diameter of the nanofibers may be in the nanoscale range, specifically about 100 nm or less.

As the thickness of the fiber is reduced in this manner, for example, an increase in the surface area ratio or the specific surface area with respect to volume and an improvement in surface function, an improvement in mechanical properties (for example, mechanical strength and flexibility), a large number of fine spaces ), That is, porosity. Through these improved properties, it can be carried out on commercial scale in most fields of application of conventional aromatic polyamide or aramid fibers, as well as in fields which are difficult to apply due to low solubility of PPTA as described above.

The thickness (or diameter) variation of the produced CY-PPTA nanofibers can be, for example, about 50% or less, specifically about 20% or less. This is because the double- (About 100%) under the same conditions using a single spinneret or the like.

The CY-PPTA nanofibers produced according to this specific example can be applied to various fields such as electronic materials such as separation membranes or separators for various cells, ultra precision filtration materials or filter fields, medical biomaterials fields, and the like. Particularly, since the nitrile group contained in the molecular structure of the CY-PPTA nanofiber interacts with nitrogen oxides (NO _x ), sulfur oxides (SO _x ) and the like in the exhaust gas, it can exhibit useful noxious gas removal (absorption or adsorption) It is expected that it will be possible to further expand the potential applicability to the environmental field.

According to another embodiment of the present disclosure, a method and an associated system for producing carbon nanofibers using CY-PPTA-based nanofibers as a carbon precursor are provided.

In this specific example, carbon nanofibers can be prepared by using CY-PPTA nanofiber obtained by using multiple spinnerets as a carbon precursor as described above.

3 is a process flow chart schematically showing a series of processes for producing carbon nanofibers according to one embodiment.

Referring to FIG. 3, the process up to the step of producing the CY-PPTA nanofibers is the same as that described above. Instead, the carbon fibers may be separately recovered and then subjected to a carbonization step (or a stabilization-carbonization step) To convert them into carbon nanofibers.

That is, it is possible to dispose the nanofibers collected at the collector end of the CY-PPTA nanofibers or any heat treatment apparatus capable of carbonizing the web, but the present disclosure is not limited to the use of the heat treatment apparatus having a specific structure . As a heat treatment apparatus for carbonization, a heating tube and an oven (using convection) can be exemplified. In this case, an inert gas atmosphere is essential for heat transfer by convection. In this type of heat treatment apparatus, the precursor fibers are configured to pass on a tension guide along a fiber spool controlled by a magnetic brake or the like, and after passing through a pulley provided with a force gauge, It is a way to pass through the heating tube. Alternatively, a heat roller type heat treatment apparatus is also applicable, wherein the apparatus of this type utilizes a conduction heat transfer.

During the above-described heat treatment (carbonization) step, weight loss may occur because components other than carbon in the precursor nanofiber are removed and some carbon sources are removed. At this time, it is preferable to convert the CY-PPTA nanofibers to carbon nanofibers while minimizing the loss of the carbon source in the precursor. According to an illustrative embodiment, at least about 85 wt.%, Specifically at least about 90 wt.%, More specifically at least about 95 wt.% Of the carbon source in the CY-PPTA based nanofiber during the carbonization step is converted to carbon.

According to exemplary embodiments, the heat treatment step for carbonization may be performed at a temperature range of, for example, about 550 to 1200 占 폚, specifically about 600 to 1000 占 폚, more specifically about 700 to 950 占 폚. In this regard, when the heat treatment temperature is excessively low or high, since the precursor CY-PPTA nanofibers are not sufficiently converted to carbon or the degree of improvement of the physical properties of the carbon nanofibers may be reduced due to excessive heat treatment, It may be advantageous to select an appropriate temperature.

On the other hand, the rate of temperature rise to the carbonization temperature during the heat treatment step may be in the range of, for example, about 1.5 to 25 ° C / min, specifically about 2 to 20 ° C / min, more specifically 4 to 10 ° C / min. The time involved in this heat treatment step may be in the range of, for example, about 10 minutes to 2 hours, specifically about 20 minutes to 1.5 hours, more specifically about 30 minutes to 1 hour.

The above-described heat treatment or carbonization step can be performed under an inert gas atmosphere, and for example, a gas such as helium, nitrogen, argon, carbon dioxide, or the like can be used. More specifically, nitrogen gas can be used. At this time, the oxygen concentration in the inert gas atmosphere may be, for example, less than about 25 ppm, specifically less than about 20 ppm, and more specifically less than about 10 ppm. Thus, the precursor nanofibers can be converted to carbon nanofibers through a carbonization process by heat treatment in an inert gas atmosphere.

According to an exemplary embodiment, the diameter of the carbon fibers produced through carbonization may range, for example, from about 4 nm to 6 占 퐉, specifically about 8 to 4.5 占 퐉, more specifically about 400 nm to 2.5 占 퐉. In certain embodiments, the diameter or thickness of the carbon nanofibers can be nanoscale (e.g., 100 nm or less).

Further, in the exemplary embodiment, the average pore size (diameter) of the carbon nanofibers may be, for example, in the range of about 0.5 to 50 nm (specifically about 1 to 10 nm) For example, about 100 to 1,000 m < 2 > / g (specifically about 200 to 600 m < 2 > / g).

On the other hand, according to this embodiment, a stabilization step for the precursor nanofibers can be additionally performed before the heat treatment step for carbonization. This stabilization step is a kind of oxidation process, in which the precursor polymer is structured in a ladder shape through a stabilization process. Through this structural modification, the carbon source is excessively pyrolyzed in the subsequent step of carbonization step to inhibit phenomena such as loss, cohesion or fusion can do.

Illustratively, it may be advantageous to have at least about 80%, especially at least about 85%, more particularly at least about 90% of the initial weight of precursor fibers, i.e., CY-PPTA based nanofibers, remaining. When the stabilization step is carried out at a residual rate less than a certain level, it may be advantageous to maintain the above-mentioned residual rate as long as the carbon fiber can not be obtained at a sufficient carbonization rate.

In an exemplary embodiment, the stabilization temperature may be selected, for example, in the range of about 150 to 400 占 폚, specifically about 180 to 300 占 폚, more specifically about 200 to 280 占 폚. At this time, the rate of temperature rise to the stabilization temperature may be in the range of, for example, about 0.5 to 20 占 폚 / min, specifically about 1 to 15 占 폚 / min, more specifically about 2 to 10 占 폚 / min.

According to an illustrative embodiment, the stabilization step may be performed under an oxygen-containing atmosphere (e.g., an air atmosphere) and may be conducted for about 10 minutes to 2 hours, specifically about 15 minutes to 1 hour, Min to 40 minutes. Illustratively, the stabilization treatment can be carried out by flowing an oxygen-containing gas in the stabilizer. Alternatively, a mixed gas in which halogen gas (for example, fluorine, chlorine, bromine, iodine, etc.) is added to the oxygen-containing gas for rapid stabilization is also applicable.

When the CY-PPTA nanofibers are used as the precursor, the stabilization step may be omitted, or even if the nanofiber is included as an optional step, the productivity of the entire process can be maintained at a high level by introducing the nanowire into a relatively short section.

The CY-PPTA precursor has very good heat resistance due to aromatic rings and amide bonds directly linked thereto, and these properties omit the stabilization steps required when using cellulose, polyacrylonitrile or pitch-based precursors used as carbon fiber precursors . Although the present invention is not limited to a specific theory, the stabilization step can be omitted because CY-PPTA produced according to this specific example has excellent heat resistance and rigidity of molecules. Therefore, even in a high temperature carbonization process, Is relatively well maintained.

The carbon nanofibers produced through the above-described procedures can be typically used for various applications by using a wide non-woven fabric, a wide specific surface area, a controlled pore size, and good electrical conductivity. Examples of such applications include electrode materials (e.g., shaker capacitors, fuel cells, lithium secondary batteries, etc.), catalyst supports, gas adsorbents, metal or plastic reinforced composite materials, and the like.

The present invention can be more clearly understood by the following examples, and the following examples are merely illustrative of the present invention and are not intended to limit the scope of the invention.

Example

CY- PPTA Synthesis of

CY-PPTA used in this example was prepared as follows.

2-Cyano-1,4-phenylenediamine (CYPPD), terephthaloyl chloride (TPC) and calcium oxide were purchased from Sigma Aldrich, and TPC was purified through vacuum distillation. NMP was purchased from Daejung Chemical as a reaction solvent and used without further purification. Calcium chloride was purchased from Junsei Chemical Company and vacuum dried for one week before use.

The reaction product was reacted according to the following reaction scheme 1 to prepare CY-PPTA.

[Reaction Scheme 1]

First, calcium chloride was dissolved in NMP and then CYPPD was added under nitrogen purge. After completely dissolving CYPPD, polymerization reaction was carried out by adding TPC under stirring. After the polymerization reaction, calcium oxide was added to neutralize the polymerization solution. As a result, a solution containing 15% by weight of CY-PPTA was formed, washed sequentially with deionized water and acetone, and dried to obtain powdery CY-PPTA. The prepared CY-PPTA was dissolved in sulfuric acid to prepare a 0.03 g / dl dilute solution. The intrinsic viscosity molecular weight was measured by extrapolation of the converted viscosity at 30 ° C using a Ubbelode viscosity tube. As a result, the intrinsic viscosity molecular weight was 5.1 dl / g.

Preparation of spinning solution

- mixed solution 1

5 g of lithium chloride (Sigma Aldrich) was added to 10 ml (95 g) of dimethylacetamide (DAE-JUNG CHEMICAL CO., LTD.) As a solvent and dissolved. At this time, the concentration of lithium chloride in the solvent was 5 wt%. 25 g of the CY-PPTA prepared above was added to the dimethylacetamide solvent in which lithium chloride was dissolved, and dissolved at 60 DEG C for 48 hours to prepare a spinning solution mixture. At this time, the content of CY-PPTA in the mixed solution was 20 wt%, and the viscosity (25 DEG C) was 2,000 cps.

- Mixed solution 2

5 g of lithium chloride (Sigma Aldrich) was added to 10 ml (95 g) of dimethylacetamide (DAE-JUNG CHEMICAL CO., LTD.) As a solvent and dissolved. At this time, the concentration of lithium chloride in the solvent was 5 wt%. 19 g of the CY-PPTA prepared above was added to the dimethylacetamide solvent in which lithium chloride was dissolved, and dissolved at 60 DEG C for 48 hours to prepare a spinning mixture solution. At this time, the content of CY-PPTA in the mixed solution was 16% by weight and the viscosity (25 DEG C) was 2,500 cps.

Three A spout  And production of electrospinning system

As shown in Figs. 1 and 2, an electrospinning system using a triple emission hole was manufactured on its own. The triple helix was made of stainless steel, and the dimensions of the inner, middle, and outer spinning holes that make up the triple spinning zone are shown in Table 1 below.

Length (mm) Internal diameter (mm) Inner spout 7 0.86 Intermediate discharge 6 1.5 Outside Spout 4 2.5

The voltage generator was a product name of HV 30 manufactured by NANON Co., Ltd. The (+) electrode was connected to the triple radiation hole and the (-) electrode was connected to the rotating collector. At this time, the collector was made of aluminum and had a diameter of 30 cm. The distance between the end of the triple emitter and the collector was 15 cm, and a voltage of 20 kV was applied to the triple emission port by the voltage generator.

Example 1

Mixture 1 was injected into the inner spinneret at a feed rate of 2 ml / h and dimethylacetamide was injected into the middle spinneret at a feed rate of 3 ml / h. A gas (air) with a pressure of 0.2 bar was supplied through the outer spinneret. A voltage was applied to the triple electric discharge port and electrospun on a collector rotating at 100 rpm at room temperature to obtain a CY-PPTA nanofiber having a diameter in the range of 0.5 to 4 mu m. Optical micrographs (× 100) and scanning electron microscopic photographs (× 1000) of the obtained CY-PPTA nanofibers are shown in FIGS. 4 and 5, respectively.

As shown in Fig. 4, it was confirmed that the CY-PPTA nanofiber was successfully prepared at room temperature by using a triple spinneret, and the diameter distribution of the CY-PPTA nanofiber obtained as shown in Fig. 5 was uniform have.

Example 2

CY-PPTA nanofiber was obtained in the same manner as in Example 1, except that a gas (air) at a pressure of 0.4 bar was supplied through the outer spinneret, wherein the diameter of the CY-PPTA nanofiber was 0.5 to 3 탆 Respectively. A scanning electron micrograph (x 1000) of the obtained CY-PPTA nanofiber is shown in Fig. According to the figure, it can be confirmed that CY-PPTA nanofibers having a uniform thickness are produced.

Example 3

The mixed solution 1 was injected into the inner spinneret at a feed rate of 4 ml / h and the intermediate spinneret was injected at a feed rate of 5 ml / h. In the same manner as in Example 1, Respectively. As a result, CY-PPTA nanofibers having a uniform diameter in the range of 1 to 5 mu m in diameter were obtained.

Example 4

Electrospinning was carried out in the same manner as in Example 1, except that the mixed solution 2 was used instead of the mixed solution 1. As a result, CY-PPTA nanofibers having a uniform diameter ranging from 1 to 4 mu m in diameter were obtained.

Comparative Example 1

CY-PPTA nanofibers were prepared using the mixed solution 1, but using a conventional spinneret in which electrospinning was not controlled by air and an organic solvent layer. At this time, only the innermost spinneret of the triple spinneret was used, and the size thereof was 0.86 mm when the length was 7 cm.

The mixed solution 1 was injected at a feed rate of 2 ml / h through a spinneret, and a nanofiber having a diameter in the range of 2 to 10 mu m was obtained by electrospinning the collector at 100 rpm by applying a voltage of 20 kV . An optical microscope photograph (x 100) of the obtained CY-PPTA nanofiber is shown in Fig. According to the figure, it can be seen that not only the diameter distribution of the nanofibers is uneven, but also a large number of bead-shaped cohesion regions are formed.

Example 5

The CY-PPTA nanofibers prepared in Example 1 were heated in an air atmosphere at a temperature raising rate of 1 DEG C / minute to a temperature of 230 DEG C for 1 hour and then heated to 270 DEG C at the same temperature raising rate for 1 hour . Thereafter, the temperature was raised to 800 ° C at a heating rate of 5 ° C / min in a nitrogen atmosphere, and then heat-treated for 30 minutes. As a result, carbon nanofibers having a diameter range of 0.5 to 4 mu m were obtained, and a scanning electron microscope (SEM) photograph (x5000) was shown in Fig.

As shown in FIG. 8, it can be confirmed that the precursor CY-PPTA nanofibers were successfully converted to carbon nanofibers while maintaining the uniform uniform thickness distribution characteristics through the carbonization process by heat treatment.

Example 6

The CY-PPTA nanofibers prepared in Example 1 were heated in an air atmosphere at a temperature raising rate of 1 deg. C / min to a temperature of 230 deg. C for 1 hour and then heated at a temperature raising rate of 5 deg. C / And then heat-treated for 30 minutes. As a result, carbon nanofibers having a diameter ranging from 0.5 to 4 탆 were obtained.

Example 7

The CY-PPTA nanofibers prepared in Example 1 were heated in an air atmosphere at a temperature rising rate of 1 DEG C / minute to a temperature of 270 DEG C for 1 hour and then heated at a rate of 5 DEG C / min at 800 DEG C And then heat-treated for 30 minutes. As a result, carbon nanofibers having a diameter ranging from 0.5 to 4 탆 were obtained.

Example 8

Carbon nanofibers were prepared in the same manner as in Example 5 except that the heat treatment temperature in a nitrogen atmosphere was changed to 900 ° C. As a result, carbon nanofibers having a diameter of 0.5 to 4 μm were obtained.

Example 9

The CY-PPTA nanofibers prepared in Example 1 were heated to 800 DEG C at a heating rate of 5 DEG C / min under a nitrogen atmosphere, and then heat-treated for 30 minutes. As a result, carbon nanofibers having a diameter in the range of 0.5 to 4 mu m were obtained, and a scanning electron microscope (SEM) photograph (x5000) thereof is shown in Fig.

As shown in FIG. 9, the precursor CY-PPTA nanofibers exhibited uniform thickness distribution characteristics while maintaining the morphological characteristics of the precursor fibers even after the carbonization step without the stabilization step, and confirmed that they were successfully converted to carbon nanofibers .

Example 10

Carbon nanofibers were prepared in the same manner as in Example 9 except that the heat treatment time was changed to 1 hour. As a result, carbon nanofibers having a diameter of 0.5 to 4 탆 were obtained.

Example 11

In this embodiment, (i) a nonwoven fabric using CY-PPTA nanofibers according to Example 1, (ii) a nonwoven fabric using CY-PPTA nanofibers after stabilization in Example 5, (iii) (Iv) Nonwoven fabrics using carbon nanofibers obtained through stabilization-carbonization as in Example 5 were prepared, and their optical microscope photographs (× 100) were prepared. 10.

As shown in FIG. 10, the nonwoven fabric made from the carbon nanofibers subjected to the carbonization or stabilization-carbonization process changes material properties with the nonwoven fabric made of the precursor CY-PPTA nanofibers or stabilized nanofibers thereof, It is confirmed that the fiber retains substantially the morphological characteristics possessed by the fibers. Therefore, it is considered that the carbon nanofibers produced have morphological improvement of the improved precursor fibers.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

10: Electrospinning system
11, 20: multiple spinnerets
12: mixed solution supply part
13: Organic solvent supply part
14:
15: Gas flow meter
16: voltage generator
17: collector
21: Inner spinner
22:
23: Outside Spout

Claims (20)

Providing a multi-spinnerette having an inner spinneret in an outward direction from the center, an intermediate spinneret surrounding the inner spinneret, and an outer spinneret surrounding the intermediate spinneret;
A mixed solution obtained by dissolving a polymer and a metal salt including CY-PPTA in an organic solvent is supplied to the inner spinneret, an organic solvent is supplied to the intermediate spinneret, and a gas is supplied to the outer spinneret and simultaneously electrospun. ; And
Recovering the nanofibers;
Based on the total weight of the nanofibers. 2. The method of claim 1, wherein the feed rate of the mixed solution supplied to the inner spinneret is 1 to 10 ml / h, the feed rate of the organic solvent supplied to the intermediate spinneret is 1 to 8 ml / h, Wherein the gas is supplied at a pressure of 0.1 to 0.5 bar. The method according to claim 1, wherein, based on the weight of the mixed solution, the mixed solution contains 10 to 23 wt% of CY-PPTA. The method according to claim 1, wherein the polymer comprising CY-PPTA has an intrinsic viscosity molecular weight of 3 to 7 dl / g. The method according to claim 1, wherein the metal salt is contained in the mixed solution in an amount of 1 to 7 wt% based on the organic solvent. The method according to claim 1, wherein the temperature of the zone where the electrospinning is progressed is in the range of 20 to 70 ° C. The method of claim 1, wherein the organic solvent is selected from the group consisting of dimethylene fluoride, tetramethylene fluoride, benzylaldehyde, ethyl acetate, acetone, acetonitrile, acetaldehyde, acetic acid, acetophenone, acetyl chloride, acrylonitrile, benzyl alcohol, Butanol, n-butyl acetate, cyclohexanol, cyclohexanone, 1,2-dibromoethane, diethyl ketone, N, N-dimethylacetamide, N, N-dimethylformamide, dimethylsulfoxide, Methyl ethyl ketone, N-methyl-2-pyrrolidone, nitrobenzene, nitromethane, 1- (2-methylpiperazin-1-yl) Propanol, propylene-1,2-carbonate, tetrahydrofuran, tetramethylurea, triethylphosphate, trimethylphosphate, ethylenediamine, N-methylmorpholine N-oxide (NMMO) And at least one selected from the group consisting of water and water is selected. The method according to claim 1, wherein the metal salt is an alkali metal halide salt and / or a halogenated alkaline earth metal salt. In wherein said metal salt is _{CaCl 2, LiCl, NaCl, KCl} , LiBr and a method of producing a nanofiber based CY-PPTA, characterized in that at least one is selected from the group consisting of KBr to claim 8. The method of manufacturing a CY-PPTA nanofiber according to claim 1, wherein the gas is air. The method according to claim 1, wherein the voltage applied during the electrospinning is in the range of 12 to 35 kV. A mixed solution supply part supplying a polymer solution containing CY-PPTA and a polymer solution obtained by dissolving a metal salt in an organic solvent;
An organic solvent supply unit for supplying an organic solvent;
A gas supply unit;
Wherein the inner radiation hole, the intermediate radiation hole, and the outer radiation hole each have an inner radiation hole, an intermediate radiation hole, and an outer radiation hole in the outward direction from the center, and each of the inner radiation hole, Spinning gates;
A collector disposed opposite the multiple emitter and collecting or accumulating CY-PPTA nanofibers emitted from the emitter; And
A voltage generator for supplying a voltage to the plurality of emitters and the collector;
/ RTI >
Wherein the mixed solution supply unit is connected to the inner spinneret, the organic solvent supply unit is connected to the intermediate spinneret, and the gas supply unit is connected to the outer spinneret. The nanofiber of claim 12, wherein the inner diameter of the inner cavity is 0.4 to 1.2 mm, the inner diameter of the intermediate cavity is 0.8 to 1.5 mm, and the inner diameter of the outer cavity is 1.5 to 20 mm. ≪ / RTI > Providing a multi-spinnerette having an inner spinneret in an outward direction from the center, an intermediate spinneret surrounding the inner spinneret, and an outer spinneret surrounding the intermediate spinneret;
A mixed solution obtained by dissolving a polymer and a metal salt containing CY-PPTA in an organic solvent is supplied to the inner spinneret, an organic solvent is supplied to the intermediate spinneret, and a gas is supplied to the outer spinneret and simultaneously electrospun, Forming a PPTA-based nanofiber;
Carbonizing the nanofibers to convert them into carbon nanofibers; And
Recovering the carbon nanofibers;
Wherein the carbon nanofibers are prepared from the CY-PPTA. 15. The method of claim 14, wherein the carbonizing step is performed at a carbonization temperature ranging from 600 to 1000 ° C. The carbon nanofiber according to claim 15, wherein the temperature is raised to a carbonization temperature at a heating rate of 2 to 20 ° C / min, and the carbonization step is performed for 10 minutes to 2 hours . The carbon nanofiber according to claim 14, further comprising a stabilization step in an oxygen-containing atmosphere prior to the carbonization step, wherein the stabilization step is performed at a stabilization temperature of 180 to 300 ° C. Gt; The carbon nanofiber according to claim 17, wherein the temperature is raised to the stabilization temperature at a heating rate of 0.5 to 20 ° C / min, and the stabilization step is performed for 20 minutes to 1 hour . 15. The method of claim 14, wherein the carbonizing step is performed in an inert gas atmosphere. A mixed solution supply part supplying a polymer solution containing CY-PPTA and a polymer solution obtained by dissolving a metal salt in an organic solvent;
An organic solvent supply unit for supplying an organic solvent;
A gas supply unit;
Wherein the inner radiation hole, the intermediate radiation hole, and the outer radiation hole each have an inner radiation hole, an intermediate radiation hole, and an outer radiation hole in the outward direction from the center, and each of the inner radiation hole, Spinning gates;
A voltage generator for supplying a voltage to the plurality of radiation sources;
A collector disposed opposite the multiple emitter and collecting or accumulating CY-PPTA nanofibers emitted from the emitter; And
A heat treatment apparatus for carbonizing the collected or integrated CY-PPTA nanofibers;
/ RTI >
Wherein the mixed solution supply unit is connected to the inner spinneret, the organic solvent supply unit is connected to the intermediate spinneret, and the gas supply unit is connected to the outer spinneret.

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