KR101966104B1 - Liquid crystal complex carbon fiber and method of manufacturing the same - Google Patents

Abstract

The present invention relates to a liquid crystal composite carbon fiber in which a liquid crystalline aromatic compound is intercalated into a graphene substance and carbonized, and a method for producing the same.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal composite carbon fiber,

The present invention relates to a liquid crystal composite carbon fiber and a manufacturing method thereof. Specifically, the present invention relates to a liquid crystal composite carbon fiber obtained by melt-spinning a liquid crystal phase blend mixture in which a liquid crystalline aromatic compound is intercalated into a graphene material through a pi-pi stacking bond, and a method for producing the same.

Generally, electrically conductive fibers (hereinafter referred to as conductive fibers) refer to fibrous materials that can contain a material that can electrically conduct electricity to the fiber itself or an internal structure thereof, and can flow a certain amount of electricity.

The conductive fiber can be classified into a method using a conductive polymer and a method combining a conductive material. The fibers manufactured by using the former technology show good conductivity above a semiconductor level, It is difficult to use for textile products. Also, fibers made of conductive polymers have low conductivity to be used for sensor applications or electrical leads.

In the latter case, more specifically, the conductive additive material may be incorporated into the fiber to produce a fiber, or the plating method may be used to coat the fiber with a common fiber. The conductive composite fiber prepared by mixing with the fiber polymer is excellent in durability and it is possible to realize various physical properties and conductivity depending on the conductive additive material and the fiber polymer to be used, but it is difficult to achieve conductivity of 10 ² S / Cm or more, which is conductive level conductivity However, it has been tried variously because of the technical difficulty in manufacturing the conductive fiber by the post-treatment coating. However, the decrease of the fiber texture and the decrease of the durability of the conductive fiber due to the coating have been disadvantageous. There is a problem.

In addition, the method of producing the conductive fiber including the conductive additive material and the graphene oxide is a technical limitation to the extent that the conductivity is generally at a level of 10 ⁰ S / cm (single digit), which is about the semiconductor, To increase the content of the conductive additive material, it is very difficult to increase the content of the conductive additive material due to the deterioration of the dispersibility due to the high melting point, the change of the additive characteristics due to the high temperature and the shear force. In addition, when the graphene oxide is dispersed in a conductive solvent and is produced by adding up to 1% by weight in preparing a solution for fiber spinning, aggregation occurs, gelation occurs, and the process efficiency is lowered And the inherent physical properties are not realized, so commercialization is delayed. All. Further, the graphene oxide is not melted at a high temperature, so that it is difficult to melt-spin the process.

Accordingly, it is necessary to conduct various studies to improve the dispersibility and the compatibility of graphene materials such as oxidized graphene, because they can be melt-spun to utilize graphene materials such as oxidized graphene as conductive fibers.

In order to solve the above problems, it is an object of the present invention to provide a liquid crystal composite carbon fiber obtained by melt-spinning the liquid crystalline aromatic compound with a liquid crystal blend mixture intercalated into a graphene material and then carbonizing the liquid crystal composite carbon fiber and a process for producing the same .

Another object of the present invention is to provide a liquid crystal composition capable of melt-spinning a liquid crystalline aromatic compound at a high concentration of a graphene material by intercalating the graphene material through π-π stacking bond and forming a liquid crystal blend of a liquid crystalline aromatic compound and a graphene- Liquid crystal composite carbon fiber obtained by melt-spinning a mixture and carbonizing the mixture, and a process for producing the same.

Another object of the present invention is to provide a liquid crystal composite carbon fiber which is capable of improving the degree of crystallization of a liquid crystalline aromatic compound and crystal orientation in a fiber axis direction by radiating a graphene-based composition, thereby significantly improving thermal conductivity and electric conductivity, .

Another object of the present invention is to provide a method for improving the spinning speed, yield, and crystallinity by preparing a graphene-based composition as fibers through melt spinning.

In order to achieve the above object, the present invention provides a method for producing a liquid crystal composite carbon fiber, comprising the steps of: a) mixing a liquid crystalline aromatic compound composition containing a liquid crystalline aromatic compound and a graphene- Preparing a liquid crystal phase blend dispersion in which the liquid crystalline aromatic compound is intercalated into the graphene based material;

b) removing the solvent of the liquid crystalline phase blend dispersion to obtain a liquid crystalline blend mixture;

c) melt spinning the liquid crystalline blend mixture to obtain a spinning fiber; And

d) carbonizing the spinning fiber to obtain a liquid crystal composite carbon fiber;

. ≪ / RTI >

The liquid crystal phase blend dispersion may contain the graphene material and the liquid crystalline aromatic compound in a weight ratio of 1: 0.5 to 1: 5.

And 0.8 to 80% by weight of graphene based on the total weight of the liquid crystal phase blend dispersion.

The liquid crystalline aromatic compound composition may contain 1 to 80% by weight of the liquid crystalline aromatic compound based on the total weight.

The liquid crystalline aromatic compound may be a polycyclic aromatic compound having an average molecular weight of 100 to 2,000 Da.

The liquid crystalline aromatic compound may be any one or a mixture of two or more selected from FCC-DO (fluidized catalytic cracking-decant oil) and coal tar.

The step d) may be carbonization at 800 to 3,000 占 폚 in an inert gas atmosphere.

The liquid crystal composite carbon fiber according to the present invention may be one in which a liquid crystalline aromatic compound is intercalated into a graphene material and carbonized.

The liquid crystalline aromatic compound and the graphene material may be intercalated through a pi-pi stacking bond.

The liquid crystal composite carbon fiber may be one obtained by carbonizing a mixture of the liquid crystalline aromatic compound and the liquid crystal phase of the graphene material by melt spinning.

The graphene material and the liquid crystalline aromatic compound may be combined in a weight ratio of 1: 0.5 to 1: 5.

The liquid crystal composite carbon fiber according to the present invention is obtained by mixing a liquid crystalline aromatic compound composition containing a liquid crystalline aromatic compound and a graphene composition containing a graphene material and then mixing the liquid crystalline aromatic compound with the graphene material By melt-spinning the mixture with a liquid-phase blend mixture and carbonizing it, it exhibits a liquid crystal phase and has the advantage of having high crystallinity and high orientation.

Further, the liquid crystal composite carbon fiber of the present invention can be produced by intercalating a liquid crystalline aromatic compound through a π-π stacking bond to a graphene material and melting and spinning the graphene material at a high concentration to have a high conductivity, Thereby improving the yield and crystallinity.

Further, the liquid crystal composite carbon fiber of the present invention has an advantage that the crystallinity of the liquid crystalline aromatic compound and the crystal orientation degree in the fiber axis direction can be improved, and thermal conductivity and electric conductivity are remarkably improved.

Further, the liquid crystal composite carbon fiber of the present invention has an excellent electrical conductivity and tensile strength, and has an advantage that it can be oriented in a liquid crystal phase.

1 is a schematic view of a method of manufacturing a liquid crystal composite carbon fiber according to an embodiment of the present invention.
FIG. 2 is a photograph of a surface (a) of a liquid crystal blend mixture according to an embodiment of the present invention, and (b) a scanning electron microscope image of a cross section. After the liquid crystalline aromatic compound is removed by etching the liquid crystal blend mixture with tetrahydrofuran a) the surface, and (b) a sectional scanning electron microscope photograph.

Hereinafter, the liquid crystal composite carbon fiber according to the present invention and a method for producing the same will be described in more detail with reference to the following examples. It should be understood, however, that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the invention.

Unless otherwise defined, all technical and scientific terms have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

The term " intercalation " as used herein means that molecules, atoms and ions are inserted between layers of a layered material, and the present invention is characterized in that a liquid crystalline aromatic compound is inserted between layers of a graphen material it means.

In order to achieve the above object, the present invention relates to a liquid crystal composite carbon fiber and a manufacturing method thereof.

Hereinafter, the present invention will be described in detail.

A method for producing a liquid crystal composite carbon fiber according to the present invention comprises the steps of: a) mixing a liquid crystalline aromatic compound composition containing a liquid crystalline aromatic compound and a graphene-based composition containing a graphene-based material, Preparing a liquid crystal phase blend dispersion intercalated in the liquid phase;

b) removing the solvent of the liquid crystalline phase blend dispersion to obtain a liquid crystalline blend mixture;

c) melt spinning the liquid crystalline blend mixture to obtain a spinning fiber; And

d) carbonizing the spinning fiber to obtain a liquid crystal composite carbon fiber;

. ≪ / RTI >

Conventionally, when a graphene material is dissolved in a solvent, gelation occurs when it is contained in an amount of 1 wt% or more at the maximum, which makes it difficult to dissolve the graphene material in a solvent to spin the graphene material to form a fiber. In order to solve the above problems, the present invention provides a blend of thermotropic liquid crystalline phase by mixing a liquid crystalline aromatic compound between layers of a graphen material to intercalate the graphene material and imparting a melting property to the graphen material having no melting characteristic. When the liquid-phase blend mixture is melt-spinnable and contains a high concentration of graphene material, there is no restriction on the gelation depending on the solvent. Further, the graphene-based material can be formed at a high concentration and a high density, so that the liquid crystal composite carbon fiber having high crystallinity can be produced, and the liquid crystal composite carbon fiber having more excellent electric conductivity can be provided. In addition, the liquid crystal composite carbon fiber of the present invention can not only recycle the liquid crystalline aromatic compound discarded as waste but also simplify the process through melt spinning, thereby lowering the cost of the carbon fiber raw material and lowering the cost of the manufacturing process .

According to an embodiment of the present invention, the graphene material may have a maximum diameter / thickness ratio of 30 or more, which is the ratio of the longest diameter to the thickness. And preferably 10,000 to 500,000. More preferably 10,000 to 100,000, but is not limited thereto. When a graphene material having the longest diameter / thickness ratio is used, it can be prepared with a critical concentration to exhibit liquid crystallinity and thus exhibits a liquid crystal phase. Since the liquid crystalline aromatic compound is uniformly mixed with the liquid crystalline aromatic compound, And can be intercalated between the layers of the pin-type material.

According to an embodiment of the present invention, the graphene material may be a reduced graphene (RG), a reduced graphene oxide (RGO), a graphene or a graphene oxide ), And the like, or a mixture of two or more thereof. In order to achieve the object of improving dispersibility and compatibility, it may be preferably graphene oxide (GO).

According to an embodiment of the present invention, the graphene oxide may be used in the same meaning as graphene oxide, oxidized graphene, oxidized graphene, or the like. Further, such an oxide graphene can be produced by a method of oxidizing a carbon material such as graphite, though there is no limitation as long as it is produced through a commonly used oxidative graphene production method. More specifically, it is possible to use graphite produced by a method of oxidizing graphite by an oxidation method such as Hummer's method, Brodie's method or Staudenmaier method.

According to an embodiment of the present invention, the degree of oxidation of the graphene material may be 1: 0.1 to 1: 2, preferably 1: 0.2 to 1: 1.5, and more preferably, Can be from 1: 0.2 to 1: 1. As described above, when a graphene-based composition having a carbon: oxygen source consumption is produced, a low viscosity can be maintained and gelation can be prevented, and a higher content of graphene-based material can be contained in the spinning solution Do.

According to an embodiment of the present invention, the graphene-based composition may be one comprising a graphene-based material and a solvent. The solvent is a solvent capable of dispersing the graphene substance. Examples of the solvent include an ether solvent, an alcohol solvent, an aromatic solvent, an alicyclic solvent, a heteroaromatic solvent, a heterocyclic solvent, an alkaline solvent, a ketone solvent, And the like. Specific examples of the solvent include chloroform, acetone, ethanol, methanol, benzene, toluene, cyclohexane, n-hexane, pyridine, quinoline, ethylene glycol, dimethylformamide, dimethylacetamide, And tetrahydrofuran, but the present invention is not limited thereto.

According to one embodiment of the present invention, the liquid crystalline aromatic compound may be a polycyclic aromatic compound having an average molecular weight measured by MALDI-TOF of 100 to 2,000 Da, preferably 100 to 1,000 Da. The liquid crystalline aromatic compound according to the present invention can impart a melting property to the graphene material and control the melting temperature of the liquid crystal phase blend mixture when the molecular weight is as described above. In addition, since the liquid crystalline aromatic compound has a polycyclic aromatic structure, fluidity can be imparted to the liquid crystal phase blend mixture at a melting point or higher, which is preferable.

The liquid crystalline aromatic compound may have a polycyclic aromatic structure having three or more aromatic rings. Specifically, it may be a polycyclic aromatic structure composed of 3 to 10 aromatic rings, but is not limited thereto.

According to one embodiment of the present invention, the liquid crystalline aromatic compound is a polycyclic aromatic compound having an average molecular weight of 100 to 2,000 Da as measured by MALDI-TOF, and specific examples thereof include a petroleum-based liquid crystalline aromatic compound FCC-DO cracking-decant oil, and coal-based liquid crystalline aromatic compounds such as coal tar, and the like, but is not limited thereto. When the liquid crystalline aromatic compound is intercalated between layers of the graphene material using a van der Waals interaction and a liquid crystal phase is formed, a meltable thermotropic liquid crystal phase can be formed. The degree of orientation of the liquid crystalline aromatic compound is not limited to the present invention but may be from 0.6 to 0.9 in order to improve the hydrocarbon yield. The liquid crystalline aromatic compound having a degree of orientation as described above is preferable because it has excellent stability in the heat treatment for carbonization, has a high carbonization yield and high crystallinity, and exhibits excellent heat and electric conduction characteristics after carbonization.

In order to uniformly blend the liquid crystalline aromatic compound and the graphene material according to the present invention to form a liquid crystal phase, the degree of oxidation of the graphene substance, the ratio of the graphene substance and the liquid crystalline aromatic compound, the molecular weight of the liquid crystalline aromatic compound Should be optimized.

The FCC-DO of the present invention refers to a byproduct remaining after producing LPG, gasoline, light oil, etc. through a fluid catalytic cracking process with vacuum gas oil generated in the refining process.

The coal tar according to an embodiment of the present invention is a black brown or black highly viscous liquid material which is produced as a by-product when coal is carbonized at 900 to 1,200 ° C. The composition is various and one or more of them is selected and included can do.

It is possible to produce a liquid crystal composite carbon fiber having high conductivity and liquid crystallinity without using a liquid crystalline aromatic compound as a raw material directly and without a step of solvent extraction and catalyst removal.

According to one embodiment of the present invention, the liquid crystalline aromatic compound composition may be prepared by including a liquid crystalline aromatic compound and a solvent. The solvent is a solvent capable of dissolving and dispersing a liquid crystalline aromatic compound. For example, the solvent may be an ether solvent, an alcohol solvent, an aromatic solvent, an alicyclic solvent, a heteroaromatic solvent, a heteroalicyclic solvent, And halogenated solvents. Specific examples of the solvent include chloroform, acetone, ethanol, methanol, benzene, toluene, cyclohexane, n-hexane, pyridine, quinoline, ethylene glycol, dimethylformamide, dimethylacetamide, And tetrahydrofuran, but the present invention is not limited thereto. The graphene-based composition and the liquid crystalline aromatic compound composition may use the same solvent. When different solvents are used, a solvent which is excellent in compatibility between the two solvents can be used.

The liquid crystal phase blend dispersion according to the present invention may contain a graphene material and a liquid crystalline aromatic compound in a weight ratio of 1: 0.5 to 1: 5, and preferably the graphene material and the liquid crystalline aromatic compound are contained in a ratio of 1: 0.5 to 1: : 3 weight ratio. When combined as described above, fluidity and radioactivity during melt spinning are improved, and a liquid crystal phase can be exhibited, which is preferable.

According to one embodiment of the present invention, 0.8 to 80% by weight, preferably 10 to 70% by weight, more preferably 20 to 70% by weight of the graphene based material may be contained relative to the total weight of the liquid crystal phase blend dispersion. When the graphene-based material is included as described above, it can be uniformly mixed with the liquid crystalline aromatic compound and can be made into a thermotropic liquid crystal phase to impart liquid crystallinity. By having a high-density graphene-based material, liquid crystal composite carbon fibers that can exhibit higher electrical conductivity by improving the degree of orientation and crystallinity are preferable.

According to one embodiment of the present invention, the liquid crystalline aromatic compound composition may contain 1 to 80% by weight, and preferably 10 to 50% by weight, of the liquid crystalline aromatic compound, based on the total weight. When the liquid crystalline aromatic compound composition is prepared in the above-described range, it can be sufficiently intercalated between the layers of the graphene material, thereby giving the graphene material a melting characteristic while being mixed with the graphene based composition, Can be controlled.

In order to uniformly disperse the liquid crystalline aromatic compound composition and the graphene composition according to an embodiment of the present invention, the liquid crystalline aromatic compound composition and the graphene composition are uniformly and stably dispersed by an ultrasonic treatment method, a mechanical stirring method, But it is not limited thereto. Further, in order to remove the impurities contained in the liquid crystal phase blend dispersion in which the liquid crystalline aromatic compound composition and the graphene composition are mixed according to an embodiment, it may be removed by dialysis or centrifugation, but the present invention is not limited thereto.

According to one embodiment of the present invention, in step b), a predetermined drying process may be performed to completely remove remaining solvent of the liquid crystalline phase blend dispersion. The drying is not particularly limited, and drying can be carried out by commonly used drying means, but is not limited thereto. For example, a vacuum pump may be used after centrifugation to separate the solvent and the graphene blend. The temperature may be raised to facilitate removal of the solvent, but is not limited thereto.

The present invention relates to a method for producing the liquid crystal composite carbon fiber by melt spinning in one embodiment, and more particularly, to a method for producing a liquid crystal composite carbon fiber by melting a liquid crystal phase blend mixture; A spinning step of melt spinning the melted liquid crystalline phase blend mixture to obtain spinning fibers; And a carbonization step of stabilizing and carbonizing the spinning fiber.

According to one aspect of the present invention, the melt spinning may be formed by extruding the melt thermoplastic material through a die spinneret. This moves down through the region of controlled temperature so that the melt is cooled below the melting temperature of the thermoplastic material and consequently comes into contact with the spinning roller. The spinning roller (filament take-up roll) can accelerate the melt filament when it is released from the die spinneret. The filament wind-up roll can then be further conditioned, stretched and wound up by the one or more additional rollers and wind-up rolls. Depending on the speed of the filament winding roll, the process may be used to produce yarns having different orientation levels. The process can be generally utilized to produce fibers of very long and essentially continuous length. The melt spinning device can also be applied without limitation, from laboratory monofilament spinning devices to industrial multifilament yarn spinning devices.

According to an embodiment of the present invention, the melting step may be performed by filling a liquid crystal blend mixture in a cylinder of a radiator, heating the mixture to 250 to 350 DEG C, and maintaining the mixture for 30 minutes to 2 hours to melt.

According to one aspect of the present invention, the spinning step is a spinning process in which the prepared liquid-phase blend mixture is spun through a spinneret at a spinning speed of 300 to 800 m / min at a spinning temperature of 250 to 350 DEG C Fibers can be produced. The uniformity and the thickness of the fiber to be produced can be determined according to the selection of the injection port, and the excellent orientation and crystallinity of the liquid crystal fiber of the spinning fiber can be expressed.

In addition, according to one aspect of the present invention, the liquid crystalline blend mixture may have spinnability that can be wound at a spinning speed of 300 to 800 m / min during melt spinning. Due to such properties, it is preferable to use a precursor material of carbon fiber because it can form spinning fibers without being well wound on spinning.

According to an embodiment of the present invention, the carbonization step corresponds to step d) by converting the spinning fiber into carbon fiber by carbonizing it. The step d) may be carbonization at 800 to 3,000 占 폚 in an inert gas atmosphere. Specifically, the temperature may be raised from room temperature to 800 to 3,000 占 폚 to 5 占 폚, and carbonization may be performed for 30 minutes to 90 minutes. When the carbonization proceeds as described above, the liquid crystal composite carbon fiber having excellent electrical conductivity can be produced by improving the mechanical properties while maintaining the shape of the spinning fiber and by increasing the density and the high carbonization.

According to an embodiment of the present invention, the carbonization step may be performed through one to three carbonization steps. The carbonization step may be carried out at different temperatures and times, respectively, when proceeding from 2 to 3 times. For example, the physical properties of the liquid crystal composite carbon fiber can be controlled through primary carbonization at 800 to 1,500 ° C, secondary carbonization at 1,200 to 1,500 ° C, and tertiary graphitization at 2,000 to 3,000 ° C, It is not.

According to an aspect of the present invention, the stabilization step may be further advanced before the carbonization step. The stabilization step may be performed by raising the temperature to 1 ° C per minute from 280 to 320 ° C in the air and oxidizing and stabilizing it for 30 to 90 minutes to prepare an infusible fiber. As the stabilizing step is carried out, the spinning fibers are separated from the hydrogen atoms in the oxidizing atmosphere by the dehydrogenation reaction and the oxidation reaction, or induce the intermolecular bonding due to the oxygen bonding. At this time, since the reacting oxygen atoms are uniformly transferred to the inside of the spinning fiber, a stable ladder structure can be formed as a whole of the spinning fiber, and it can have excellent salt resistance.

In the stabilization step, the low-boiling point component is volatilized through the softening melt phase, and a part of the low-boiling point component is thermally decomposed and released to the outside of the system. The remaining components are activated to cause cyclization, aromatization and polycondensation, Is a liquid-phase carbonization reaction. The liquid crystalline aromatic compound, which is a polycyclic aromatic plane molecule intercalated between the layers of the graphene material in the spinning fiber, aggregates the van der Waals force with a driving force and is stacked in parallel with each other through the stabilization step as described above, Can be further improved.

The liquid crystal composite carbon fiber according to the present invention will be described in detail as follows.

The liquid crystal composite carbon fiber according to the present invention may be one in which a liquid crystalline aromatic compound is intercalated into a graphene material and carbonized. Or may be one produced by the above-described production method.

Specifically, the liquid crystal composite carbon fiber may be one in which the liquid crystalline aromatic compound is intercalated into the graphene material through π-π stacking bond. The π-π stacking bond is a structure in which polycyclic aromatic groups are piled up and bonded to each other. Specifically, for example, a liquid crystalline aromatic compound, which is a polycyclic aromatic compound, is bonded with strong interaction between the surfaces of the graphen materials, However, by forming a sufficient amount of pi-pi stacking bonds, the liquid crystal composite carbon fibers thus produced can exhibit excellent mechanical strength.

According to an embodiment of the present invention, the liquid crystal composite carbon fiber may be obtained by melt-spinning and carbonizing a liquid crystal blend mixture of a liquid crystalline aromatic compound and a graphene material. When a conventional graphene-based material is dissolved in a solvent, when the graphene-based material contains at most 1% by weight, gelation occurs and the fluidity is limited to a high viscosity, so that a graphene-based composition containing a low- The improvement of the electrical conductivity was limited. However, according to the present invention, since the liquid crystal composite carbon fiber is produced by melt spinning as described above, it can be formed into a high density fiber including a high concentration of graphene material, so that it can have more excellent electric conductivity.

Further, according to an embodiment of the present invention, the liquid crystal composite carbon fiber has a graphene-like material oriented in the graphene-based composition, and can improve the degree of crystallization of the liquid crystalline aromatic compound and the degree of crystal orientation in the fiber axis direction, And electrical conductivity.

In the liquid crystal phase blend dispersion of the present invention, the graphene material and the liquid crystalline aromatic compound may be contained in a weight ratio of 1: 0.5 to 1: 5, and preferably the graphene material and the liquid crystalline aromatic compound are contained in a ratio of 1: 0.5 to 1: 1: 3 weight ratio. When combined as described above, fluidity and radioactivity during melt spinning are improved, and a liquid crystal phase can be exhibited, which is preferable.

The liquid crystal composite carbon fiber according to the present invention can obtain both the advantages of the graphene-based material and the advantages of the liquid crystal simultaneously. The liquid crystal composite carbon fiber according to the present invention can control its directionality by using external fields such as a magnetic field and a flow field, Can exhibit anisotropic optical, genetic and mechanical properties, which can broaden the utilization of graphene materials and establish new processes.

Hereinafter, the liquid crystal composite carbon fiber according to the present invention and a method for producing the same will be described in more detail with reference to the following examples. It should be understood, however, that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the invention.

Unless otherwise defined, all technical and scientific terms have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

In addition, the unit of the additives not specifically described in the specification may be% by weight.

[Production Example 1]

A liquid crystalline aromatic compound composition in which 2 wt% of FCC-DO (fluidized catalytic cracking-decant oil, MALDI-TOF average molecular weight of 300 Da, degree of orientation 0.673) was dissolved in tetrahydrofuran was prepared. A graphene composition was prepared in which 2 wt% of graphene oxide (manufactured by Standard Grain Co., Hummer's method, degree of oxidation: carbon: oxygen source consumption of 1: 0.6) was dissolved in tetrahydrofuran. The liquid crystalline aromatic compound composition and the graphene composition were mixed at a weight ratio of 1: 1 to prepare a liquid crystal phase blend dispersion. The liquid crystal phase blend dispersion was centrifuged and the tetrahydrofuran was completely removed using a vacuum pump to prepare a liquid crystal blend mixture.

[Production Example 2]

In the same manner as in Production Example 1, 2 weight% of liquid crystalline catalytic cracking-decent oil (FCC-DO) was dissolved in tetrahydrofuran in place of 2 weight% of liquid crystalline aromatic compound The same was used except that the compound composition was used.

[Production Example 3]

In Example 1, 4% by weight of FCC-DO (fluidized catalytic cracking-decant oil) was used in the same manner except that a liquid crystalline aromatic compound solution dissolved in tetrahydrofuran was used.

[Production Example 4]

Except that a liquid crystalline aromatic compound composition dissolved in tetrahydrofuran was used as FCC-DO (fluidized catalytic cracking-decanyl oil) at 0.5% by weight in Preparation Example 1.

[Production Example 5]

A graphene oxide (manufactured by Standard Grafflin Co. Hummer's method) was used in the same manner as in Preparation Example 1, except that a graphene composition dissolved in tetrahydrofuran was used in an amount of 3% by weight.

[Production Example 6]

Except that FCC-DO (fluidized catalytic cracking-decant oil) was used in FCC-DO: coal tar ratio = 50: 50 weight ratio in Production Example 1.

[Production Example 7]

Except that the degree of oxidation of the graphene oxide in Production Example 1 was 1: 1.

[Production Example 8]

Except that the degree of oxidation of the graphene oxide in Production Example 1 was 1: 2.

[Production Example 9]

Except that the MALDI-TOF average molecular weight of FCC-DO in Example 1 was 500 Da and the degree of orientation was 0.701.

[Production Example 10]

Except that the MALDI-TOF average molecular weight of FCC-DO in Example 1 was 800 Da and the degree of orientation was 0.510.

[Production Example 11]

Except that a graphene-based composition containing 5 wt% of graphene oxide was used in Production Example 1 above.

[Comparative Production Example 1]

Except that the liquid crystalline aromatic compound was not used in Production Example 1 and only the graphene-based composition was used as a spinning solution. However, the graphene oxide of the graphene-based composition did not dissolve and could not be spun into fibers.

[Example 1]

1. Melting step

The liquid crystal blend mixture prepared in Preparation Example 1 was filled in a cylinder of a radiator and heated. The temperature was raised to 350 DEG C and maintained for 30 minutes to secure thermal stability. Then, the mixture was kept at 300 DEG C for 1 hour to form a liquid crystal blend The mixture was melted.

2. Radiation step

The spinning temperature of the liquid crystalline blend mixture was lowered to 300 캜 and spun at a pressure of 0.5 bar under a nitrogen pressure to obtain a spinning fiber. The diameter of the spinneret used was 0.5x0.5 mm, and the spinning fiber was wound at a speed of up to 300 m / min.

3. Oxidation Stabilization Step

The spinning fibers obtained by melt spinning were heated to 1 ° C per minute while circulating air using a hot air circulating path and maintained at 300 ° C for 1 hour for oxidation stabilization.

4. Carbonization (Carbonization) Step

 The stabilized fibers obtained through the stabilization step were heated to 1,000 ° C at a rate of 5 ° C / min under a nitrogen atmosphere and maintained for 1 hour to prepare a liquid crystal composite carbon fiber.

[Example 2]

A liquid crystal phase blend mixture was prepared in the same manner as in Example 1 except that the liquid crystal phase blend mixture prepared in Preparation Example 2 was used.

[Example 3]

The same procedure was performed as in Example 1 except that the liquid crystal phase blend mixture used in Production Example 3 was used.

[Example 4]

A liquid crystal phase blend mixture was prepared in the same manner as in Example 1 except that the liquid crystal phase blend mixture prepared in Preparation Example 4 was used.

[Example 5]

Except that the liquid crystal phase blend mixture prepared in Preparation Example 5 was used in Example 1.

[Example 6]

A liquid crystal phase blend mixture was prepared in the same manner as in Example 1 except that the liquid crystal phase blend mixture prepared in Preparation Example 6 was used.

[Example 7]

The same procedure was carried out as in Example 1 except that the liquid crystal phase blend mixture used in Production Example 7 was used.

[Example 8]

The same procedure was carried out as in Example 1 except that the liquid crystal phase blend mixture used in Production Example 8 was used.

[Example 9]

A liquid crystal phase blend mixture was prepared in the same manner as in Example 1 except that the liquid crystal phase blend mixture prepared in Production Example 9 was used.

[Example 10]

A liquid crystal phase blend mixture was prepared in the same manner as in Example 1 except that the liquid crystal phase blend mixture prepared in Preparation Example 10 was used.

[Example 11]

A liquid crystal phase blend mixture was prepared in the same manner as in Example 1 except that the liquid crystal phase blend mixture used in Production Example 11 was used.

[Example 12]

After the stabilization step in Example 1, the carbonization step was carried out at 800 ° C for primary carbonization, 1,200 ° C for secondary carbonization and 2,000 ° C for tertiary carbonization at 5 ° C / min and maintained for 1 hour, Carbonization was carried out in the same manner.

[Experimental Example 1] Confirmation of orientation of liquid crystal phase blend mixture.

As shown in FIG. 2, when the surface (a) and the cross section (b) of the liquid crystal phase blend mixture of Production Example 1 of the present invention were observed with a scanning electron microscope, the liquid crystalline aromatic compound was uniformly dispersed . In order to clearly confirm that the liquid crystalline aromatic compound is intercalated between the graphene oxide layers in this way, the liquid crystalline aromatic compound of the liquid crystal phase blend mixture is removed by etching with tetrahydrofuran, and the surface (c), the cross section (d) And observed with a scanning electron microscope. It was confirmed that the liquid crystalline aromatic compound was intercalated in the graphene oxide layer through the removal of the liquid crystalline aromatic compound and the skeleton of the graphene oxide by the etching of the liquid crystalline blend mixture. Thus, it can be confirmed that the liquid crystal phase blend mixture of the present invention uniformly has a liquid crystalline aromatic compound present between graphene oxide layers and has an oriented structure.

[Experimental Example 2]

1. Measurement of electrical conductivity of liquid crystal composite carbon fiber

The electrical conductivity of the liquid crystal composite carbon fiber of the embodiment was measured using a CMT-SR1000N manufactured by ACITECH CORPORATION with a 1 cm interval between the electrodes, a sample was contacted with the sample, and a 4-point probe Measurement method was used.

2. Tensile strength

Tensile strength was measured using UTM 5982 by making a test specimen according to ASTM D 638 (Standard Test Method for Tensile Properties of Plastics). (Tensile strength [Pa] = maximum load [N] / area of initial sample [m2])

3. Radioactive

Radioactivity was evaluated by the following criteria.

○: There is no trouble such as fiber breakage, and winding is possible.

△: Sometimes there is a fiber break, but it can be wound at a specified winding speed.

X: Unwinding at the specified winding speed.

4. Raman analysis (crystallinity)

Has an absorption region of 1350~1380 cm ^-1 (D peak) and 1580~1600cm ^-1 (G peak), it is possible to determine the crystallinity of a carbon fiber according to the intensity and width of the two regions. D peak is related to the amorphous state of the carbon structure of carbon atoms, and G peak (graphite peak) shows graphite crystal structure in sp ² hybrid orbital bonding. The relative crystallinity improvement was evaluated by the peak intensity value (Id / Ig) of each region.

It was confirmed that the liquid crystal composite carbon fibers prepared in Examples 1 to 12 had excellent electrical conductivity, tensile strength and crystallinity.

In addition, the liquid crystal composite carbon fiber produced by the embodiment of the present invention is formed by melting a graphene material having no melting characteristic as the liquid crystalline aromatic compound is intercalated through the pi-pi stacking bond between the layers of the graphene material, , The content of the graphene substance can be further increased. Further, the spinning rate was increased by melt spinning, and the yield and crystallinity could be further improved.

Further, it was confirmed that the liquid crystalline aromatic compound of the present invention had a degree of orientation of 0.6 to 0.9, and an average molecular weight of 100 to 2,000 Da as measured by MALDI-TOF had further improved electrical conductivity and crystallinity.

Further, it has been confirmed that the degree of oxidation of the graphene oxide of the present invention has better electrical conductivity and crystallinity when the carbon: oxygen source consumption is 1: 0.2 to 1: 1.

As described above, the liquid crystal composite carbon fiber and the method of manufacturing the same according to the present invention have been described in order to facilitate an overall understanding of the present invention. However, the present invention is not limited to the above- It is to be understood that the invention is not limited to those precise embodiments, and various modifications and changes may be made thereto by those skilled in the art.

Accordingly, the spirit of the present invention should not be construed as being limited to the embodiments described, and all of the equivalents or equivalents of the claims, as well as the following claims, belong to the scope of the present invention .

Claims (11)

a) mixing a liquid crystalline aromatic compound composition containing a liquid crystalline aromatic compound having an average molecular weight of 100 to 2,000 Da as measured by MALDI-TOF and a graphene-based composition containing a graphene-based material, Preparing a liquid crystal phase blend dispersion intercalated in the material;
b) removing the solvent of the liquid crystalline phase blend dispersion to obtain a liquid crystalline blend mixture;
c) melt spinning the liquid crystalline blend mixture to obtain a spinning fiber; And
d) carbonizing the spinning fiber to obtain a liquid crystal composite carbon fiber;
Wherein the liquid crystal composite carbon fiber has an average particle diameter of not more than 100 nm. The method according to claim 1,
Wherein the liquid crystal phase blend dispersion comprises a graphene material and the liquid crystalline aromatic compound in a weight ratio of 1: 0.5 to 1: 5. The method according to claim 1,
And 0.8 to 80 wt% of graphene based on the total weight of the liquid crystal phase blend dispersion. The method according to claim 1,
Wherein the liquid crystalline aromatic compound composition comprises 1 to 80 wt% of a liquid crystalline aromatic compound based on the total weight of the liquid crystalline aromatic compound composition. delete The method according to claim 1,
Wherein the liquid crystalline aromatic compound is any one or a mixture of two or more selected from among FCC-DO (fluidized catalytic cracking-decant oil) and coal tar. The method according to claim 1,
Wherein the step d) is carbonized at 800 to 3,000 占 폚 in an inert gas atmosphere. A liquid crystalline aromatic compound having an average molecular weight of 100 to 2,000 Da as measured by MALDI-TOF is intercalated into a graphene material and carbonized. 9. The method of claim 8,
Wherein the liquid crystalline aromatic compound and the graphene material are intercalated through a pi-pi stacking bond. 9. The method of claim 8,
Wherein said liquid crystal composite carbon fibers are obtained by melt-spinning and carbonizing said liquid crystalline aromatic compound and a liquid crystal phase blend mixture of said graphene material. 9. The method of claim 8,
Wherein the graphene material and the liquid crystalline aromatic compound are combined in a weight ratio of 1: 0.5 to 1: 5.

Images