KR102544810B1 - Carbon fiber and method of manufacturing the same - Google Patents

Abstract

The present invention relates to carbon fibers obtained by preparing pitch having a high softening point by using electromagnetic waves in a blend dispersion containing a polycyclic aromatic residue composition and a carbon-based composition, melt-spinning the pitch, and then carbonizing the same, and a method for producing the same. More specifically, it relates to a method for producing pitch with a high softening point that is inexpensive, environmentally friendly, and melt-spinable through a short reaction time without using a catalyst.

Description

Carbon fiber and its manufacturing method {CARBON FIBER AND METHOD OF MANUFACTURING THE SAME}

The present invention relates to carbon fiber and a method for producing the same. Specifically, a method for producing carbon fiber comprising the steps of preparing pitch having a high softening point by applying electromagnetic waves to a blend dispersion containing a polycyclic aromatic residue composition and a carbon-based composition, melt-spinning and carbonizing the pitch, and carbon produced thereby It's about fibers.

Despite the progress in the development of new and renewable energy, the world's average oil consumption per day last year was 99.843 million barrels, and petroleum products are still mostly used as energy sources. Petroleum products are obtained through the fractional distillation and refining process of crude oil, during which a large amount of petroleum residue is produced as a by-product. Such petroleum-based residue oil is known as a raw material suitable for high value-added carbon materials such as high-strength carbon fiber due to its high degree of aromatization and low content of impurities such as sulfur. A lot of related research, such as the manufacture of

The high softening point pitch manufacturing process that can be melt-spun is uniform and requires a long heat treatment of 7 to 10 hours at a high temperature of 400 to 430 ° C to have a high molecular weight, so energy consumption is high and the process is complicated, so the process cost is high. In addition, simple thermal polymerization of petroleum-based residue oil vaporizes low-molecular-weight materials, making it difficult to produce high-yield (20% or more) high-softening pitch pitch having a narrow molecular weight distribution. On the other hand, a method for producing pitch using a cationic polymerization using AlCl ₃ or HF/BF ₃ and halogenated dehalogenation by adding a halogen catalyst such as Cl ₂ or Br ₂ is known. The above production method can obtain a relatively high yield and a high softening point pitch with a narrow molecular weight distribution by lowering the reaction temperature, but there is a problem in that it is difficult to remove impurities and is expensive for manufacturing equipment and operation due to high corrosiveness and stability of the catalyst. . In addition, there is a method of producing pitch for carbon fiber using dicumylperoxide (DCP), benzoyl peroxide, etc., which are radical initiators made of organic polymers, as polymerization initiators, but the condensation polymerization reaction of PFO is mainly used. It is difficult to obtain a high degree of condensation even when a relatively large amount of initiator is used, since the formed radicals are easily removed by being non-radical or volatilized at 250 ° C or higher.

Accordingly, it is necessary to develop a technology capable of producing a high-softening point pitch that is inexpensive, environmentally friendly, and can stably form radicals that can be melt-spun.

Republic of Korea Patent Registration No. 10-2045042 B1 (2019.11.08)

An object of the present invention relates to a method for producing carbon fiber using a petroleum-based or coal-based residue composition, and specifically, a pitch having a high softening point that does not use a catalyst, is inexpensive and environmentally friendly, and can be melt-spun through a short reaction time. (including mesophase pitch) to provide a method for producing.

In addition, another object of the present invention is to provide a method for producing carbon fibers using the pitch of the high softening point as described above, and more specifically, to provide a method for manufacturing liquid crystal composite carbon fibers having isotropy or anisotropy. .

In addition, another object of the present invention is to use a high-volatility, low-molecular-weight polycyclic aromatic compound residue composition, which has not been utilized in the conventional manufacturing method of producing pitch from a polycyclic aromatic compound residue composition, as a raw material for pitch to the extent that there is substantially little loss, , to improve economic efficiency by converting it to a high yield.

In addition, another object of the present invention is to provide a method for economically producing carbon fibers by oxidative stabilization in a short time using pitch having a high softening point as described above.

A method for producing carbon fibers according to the present invention includes a) mixing a polycyclic aromatic compound residue composition containing a polycyclic aromatic compound and a carbon-based composition containing a one-dimensional or two-dimensional carbon-based material, and mixing the polycyclic aromatic compound residue composition and the carbon-based material preparing a blend dispersion in which the composition is intercalated; b) preparing pitch by applying electromagnetic waves to the blend dispersion; c) melt-spinning pitch to obtain spun fibers; and d) carbonizing the spun fibers to obtain carbon fibers.

In the carbon fiber manufacturing method according to an embodiment of the present invention, the polycyclic aromatic compound residue composition may include petroleum-based polycyclic aromatic compound residue or coal-based polycyclic aromatic compound residue.

In the carbon fiber manufacturing method according to an embodiment of the present invention, the polycyclic aromatic compound residue composition may include a polycyclic aromatic compound having an average molecular weight of 10 to 1,000 Da as determined by MALDI-TOF.

In the carbon fiber manufacturing method according to an embodiment of the present invention, the polycyclic aromatic compound residue composition may be LMFD (Low-Molecular weight Fluidized Catalytic Cracking-Decant Oil).

In the carbon fiber manufacturing method according to an embodiment of the present invention, the carbon-based composition is selected from the group consisting of single-walled carbon nanotubes, multi-walled carbon nanotubes, graphene nanoribbons, carbon nanofibers, and carbon nanowires Any one or two or more one-dimensional carbon-based materials may be included.

In the carbon fiber manufacturing method according to an embodiment of the present invention, the carbon-based composition is any one selected from the group consisting of graphene, graphene oxide (GO), and reduced graphene oxide (rGO), or two or more 2 dimensional carbon-based materials.

In the carbon fiber manufacturing method according to an embodiment of the present invention, the blend dispersion may include the carbon-based composition and the residue composition of the monocyclic aromatic compound in a weight ratio of 1:0.01 to 1:0.2.

In the carbon fiber manufacturing method according to an embodiment of the present invention, electromagnetic waves include gamma rays, X-rays, visible rays, near infrared rays (NIR), infrared rays, ultraviolet rays, microwaves, microwaves, very short waves, short waves, medium waves, long waves, low frequencies, high frequencies, It may include any one selected from the group consisting of ultra-high frequency.

In the carbon fiber manufacturing method according to an embodiment of the present invention, the intercalated blend dispersion may be a liquid crystal blend dispersion.

In the carbon fiber manufacturing method according to an embodiment of the present invention, in step b), the microwave may be irradiated with an intensity of 300 to 15,000 W and 0.001 seconds to 600 minutes.

In the carbon fiber manufacturing method according to an embodiment of the present invention, the pitch may be anisotropic pitch having a softening point of 150 to 370 °C and an average molecular weight of 300 to 2,000 Da.

In the carbon fiber manufacturing method according to an embodiment of the present invention, after step c), a step of stabilizing by irradiating electromagnetic waves may be further included.

The carbon fiber according to the present invention is carbonized after melt spinning pitch prepared by applying electromagnetic waves to a blend dispersion in which a polycyclic aromatic compound residue composition and a carbon-based composition are intercalated.

The carbon fiber manufacturing method according to the present invention does not use a catalyst, is inexpensive and environmentally friendly, and can produce pitch with a high softening point capable of melt spinning through a short reaction time. Specifically, by utilizing the structural characteristics of the carbon-based composition, the carbon-based composition forms radicals through electromagnetic waves, so that the petroleum or coal-based residue composition proceeds to polymerize around the carbon-based composition, so that pitch having a high softening point is easily formed. It can be manufactured, and the manufactured high softening point pitch can be made of carbon fiber. More specifically, the pitch of the prepared high softening point may be isotropic or anisotropic pitch, and the isotropic pitch may activate pores to produce activated carbon fibers, and the anisotropic pitch is a mesophase pitch, which has excellent It can be made of carbon fiber with mechanical properties and electrical conductivity. In addition, the carbon fiber manufacturing method according to the present invention is a raw material for pitch to the extent that there is substantially little loss of the highly volatile, low molecular weight polycyclic aromatic compound residue composition, which was not available in the conventional manufacturing method of producing pitch from the polycyclic aromatic compound residue composition. , and can also dramatically reduce the reaction time, and significantly improve the yield of pitch produced.

In addition, in the carbon fiber manufacturing method according to the present invention, carbon fibers can be economically manufactured in a short time by oxidation stabilization using pitch in a short time.

1 is a schematic diagram of a carbon fiber manufacturing method according to an embodiment of the present invention, (a) shows a blend dispersion in which graphene is intercalated with petroleum residue, and (b) shows a micro-processing of the blend dispersion. The pitch of the high softening point formed by doing, (c) shows the carbon fiber.
Figure 2 shows a scanning electron microscope (Scanning Electron Microscope, SEM) picture of the liquid crystal composite fiber prepared in Example 1 of the present invention.
2 (a) shows the carbon fiber prepared in Example 1, and (b) shows a cross section of the produced carbon fiber. 2(c) and (d) show cross sections of carbon fibers magnified by 33,750 times and 975,000 times, respectively.

Hereinafter, the present invention will be described in more detail through specific examples or examples including the accompanying drawings. However, the following specific examples or examples are only one reference for explaining the present invention in detail, but the present invention is not limited thereto, and may be implemented in various forms.

Also, unless defined otherwise, 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. Terms used in the description in the present invention are merely to effectively describe specific embodiments and are not intended to limit the present invention.

Also, the singular forms used in the specification and appended claims may be intended to include the plural forms as well, unless the context dictates otherwise.

In addition, when a certain component is said to "include", this means that it may further include other components without excluding other components unless otherwise stated.

In the present specification, “intercalation” means that molecules, atoms, or ions are inserted between layers of a material having a layered structure, and the present invention relates to a liquid crystal between layers of a carbon-based material, specifically a graphene-based material. It means that an aromatic compound is inserted.

The terms “anisotropic” and “mesophase” used herein have the same meaning.

The present invention for achieving the above object provides a carbon fiber and a manufacturing method thereof.

The present invention will be described in detail as follows.

A method for producing carbon fibers according to the present invention includes a) mixing a polycyclic aromatic compound residue composition containing a polycyclic aromatic compound and a carbon-based composition containing a one-dimensional or two-dimensional carbon-based material, and mixing the polycyclic aromatic compound residue composition with carbon preparing a blend dispersion of the based composition; b) preparing pitch by applying electromagnetic waves to the blend dispersion; c) melt-spinning the pitch to obtain spun fibers; and d) carbonizing the spun fibers to obtain carbon fibers.

In the conventional method for producing pitch using a polycyclic aromatic compound residue composition, highly volatile low molecular weight materials are rapidly volatilized and the yield is low, so it cannot be used as an economical pitch raw material. There was a problem of low productivity in the manufacturing process. In order to solve this problem, in the present invention, the polycyclic aromatic compound residue composition of high volatility and low molecular weight can be used as a raw material for pitch to the extent that the amount of loss is substantially reduced by using electromagnetic waves, and the reaction time can be dramatically reduced. A carbon fiber production method that can significantly improve the yield of pitch has been completed. The pitch produced using electromagnetic waves as described above has a high softening point and has isotropic or anisotropic characteristics. Pitch (mesophase pitch) has the advantage of being able to produce carbon fibers having higher crystallinity, higher conductivity, higher strength, and higher modulus of elasticity than isotropic pitch, and also capable of manufacturing long-fiber carbon fibers.

In addition, the carbon fiber manufacturing method according to the present invention can utilize the polycyclic aromatic compound residue composition discarded as waste, and simplify the process through melt spinning to lower the price of the carbon fiber raw material and secure the economic feasibility of the manufacturing process. can

Hereinafter, each step of the present invention will be described in more detail.

In the step a), the blend dispersion may include the polycyclic aromatic compound residue composition and the carbon-based composition in a weight ratio of 1:0.0001 to 1:1, preferably a weight ratio of 1:0.001 to 1:0.5, more preferably Preferably, it may be included in a weight ratio of 1: 0.01 to 1: 0.2. By mixing in the above weight ratio, the pitch can be produced with a high conversion rate by the treatment of electromagnetic waves, and the manufactured pitch has a sufficiently high softening point, enabling stabilization under conditions of 200 ° C. or higher in the air, which is a process before carbonization. desirable.

As a preferred example, when the carbon-based composition includes the two-dimensional carbon-based material in the above weight ratio, the blend dispersion may exhibit a liquid crystal phase, which is preferable. In the blend dispersion prepared by mixing the carbon-based composition with the polycyclic aromatic compound residue composition and including the two-dimensional carbon-based material, the polycyclic aromatic compound is effectively intercalated with the two-dimensional carbon-based material through ππ stacking. can be formed The ππ stacking is that polycyclic aromatic groups are stacked and bonded to each other flatly. For example, a liquid crystalline aromatic compound, which is a polycyclic aromatic compound, is stacked with a strong interaction between the planes of the two-dimensional carbon-based material, and the bond strength is Although it is weak, by forming a sufficient amount of ππ laminate, the carbon fiber prepared therefrom can express excellent mechanical strength and electrical conductivity.

The blend dispersion may be uniformly and stably dispersed by an ultrasonic treatment method, a mechanical stirring method, or a mixing method thereof in order to uniformly disperse the residue composition of the polycyclic aromatic compound and the carbon-based composition, but is limited thereto. It is not. According to one embodiment, in order to remove impurities contained in the blend dispersion in which the polycyclic aromatic compound residue composition and the carbon-based composition are mixed, dialysis or centrifugation may be used to remove impurities to improve the uniformity of physical properties of the pitch. It is an example, but not limited thereto.

The polycyclic aromatic compound residue composition may include petroleum-based polycyclic aromatic compound residue or coal-based polycyclic aromatic compound residue. Specifically, pyrolyzed fuel oil (PFO), naphtha cracking bottom oil (NCB), ethylene bottom oil (EBO), heavy oil, extra heavy oil, vacuum residue (VR) ), at least one selected from the group consisting of atmospheric residue oil, fluid catalytic cracking decant oil (FCC-DO), de-asphalted oil (DAO), and coal tar, and more specifically In this case, the polycyclic aromatic compound residue composition may be more specifically fluid catalytic cracking decant oil (FCC-DO), and specifically, LMFD (Low- Molecular weight fluidized catalytic cracking-decant oil). The LMFD may have a high degree of orientation, and specifically may have a degree of orientation of 0.5 to 0.9. The degree of aromatization indicates the content of the aromatic component calculated by the Brown-Ladner method.

Conventionally, in order to prepare pitch using petroleum residue, after removing highly volatile low molecular weight components, the remaining components have been condensed and converted into polymers, and the pitch produced from petroleum residue has isotropy. However, in a preferred aspect of the present invention, a low molecular weight with high volatility is not excluded, but rather can be preferably used as a raw material for pitch, and, unlike the prior art, it has better mechanical properties than isotropic pitch and is manufactured as an anisotropic pitch having high added value can do.

The average molecular weight of the polycyclic aromatic compound residue composition is not limited, but may be 10 to 1,000 Da by MALDI-TOF.

An example of the polycyclic aromatic compound residue composition may be LMFD (Low-Molecular weight Fluidized Catalytic Cracking-Decant Oil), which is a highly volatile, low-boiling material, and specifically, may have an average molecular weight of 20 to 800 Da by MALDI-TOF. . Most of the highly volatile, low molecular weight polycyclic aromatic compound residue composition is volatilized and removed at a typical pitch manufacturing process temperature. For this reason, the high-volatility, low-molecular-weight polycyclic aromatic compound has been removed in advance before the pitch manufacturing process to maintain uniformity of physical properties of the pitch. However, the carbon fiber manufacturing method according to the present invention can be converted into pitch with virtually no loss despite including the high volatility, low molecular weight polycyclic aromatic compound residue composition as a main raw material in the pitch manufacturing step, and subsequently It has the advantage of being converted into high value-added carbon fiber.

The carbon-based composition may include any one or two or more of a one-dimensional carbon-based material and a two-dimensional carbon-based material. As a one-dimensional carbon-based material, single-wall carbon nanotubes (SWNTs), multi-wall carbon nanotubes (MWNTs), and graphene nanoribbons (GNRs) are one-dimensional carbon-based materials. , Carbon nanofibers (carbon nanofibers) and carbon nanowires (carbon nanowire) may be any one 　 or a combination of two or more selected from the group consisting of. The two-dimensional carbon-based material may be any one or a combination of two or more selected from the group consisting of graphene, graphene oxide (GO), and reduced graphene oxide (rGO).

In a preferred aspect, the carbon-based composition exhibits a high pitch conversion rate by effectively generating heat by absorbing electromagnetic waves in the step b), and at the same time improves the anisotropy of the pitch. It may include a two-dimensional carbon-based material. More preferably, specifically reduced graphene oxide can be exemplified as a preferable material of the two-dimensional carbon-based material.

The diameter of the carbon-based material may be 50 nm to 100 μm, specifically 100 nm to 10 μm, but is not limited thereto. The aspect ratio (major axis diameter/thickness) of the two-dimensional carbon-based material may be 5 or more, 10 or more, and less than 10,000, but is not limited thereto.

As another preferred aspect, the carbon-based composition may be a mixture of a one-dimensional carbon-based material and a two-dimensional carbon-based material. As the mixture of the one-dimensional carbon-based material and the two-dimensional carbon-based material is included, it is possible to secure pitch anisotropy and obtain carbon fibers having better electrical conductivity through a subsequent carbonization step.

In the step b), the electromagnetic wave is any one selected from the group consisting of gamma rays, X-rays, visible rays, near infrared rays (NIR), infrared rays, ultraviolet rays, microwaves, microwaves, microwaves, short waves, medium waves, long waves, low frequencies, high frequencies, and ultra-high frequencies. It may contain. Microwaves may be preferably used, and at this time, the microwaves may be irradiated at an intensity of 100 to 30,000 W, specifically 300 to 15,000 W, for 0.0001 seconds to 800 minutes, specifically 0.001 seconds to 600 minutes, but are limited thereto It is not. The present invention is preferable because the radical reaction between the polycyclic aromatic compound and the carbon-based composition can be efficiently and sufficiently carried out in a short time using electromagnetic waves, and pitch with excellent physical properties and high softening point can be prepared.

The pitch produced by the above manufacturing method can implement excellent physical properties suitable for melt spinning. The pitch may have a high softening point of 200 to 360 °C, preferably 250 °C to 320 °C, an average molecular weight of 300 to 2,000 Da, and preferably an anisotropic pitch. The anisotropic pitch forms a layered structure in which condensed polycyclic aromatic planar molecules are arranged in parallel, exhibits fluidity below the reaction temperature to form an anisotropic phase, and has excellent spinnability, making it difficult to manufacture carbon fibers. Suitable. In addition, carbon fibers made of anisotropic pitch have superior mechanical or electrical properties than carbon fibers made of isotropic pitch.

In addition, the yield of the pitch produced by the production method of the present invention is more than 50%, which is economically more preferable because it not only has a significantly improved production yield compared to the prior art, but also can be produced in a short time. More specifically, the pitch yield may be 60% or more, and more specifically, the pitch yield may be 80% or more.

When an electromagnetic wave is applied to a blend dispersion in which the polycyclic aromatic compound residue composition and the carbon-based composition are intercalated, radicals may be formed at structural edges or defective portions or polar functional groups (hydroxyl group, carboxyl group, etc.) of the carbon-based composition. there is. In addition, the carbon-based composition absorbs electromagnetic waves and becomes high-temperature in a short time, and polycyclic aromatic compound residue composition proceeds to polymerize through condensation polymerization and radical reaction along the sp2 bonded crystal plane of the carbon-based material, resulting in anisotropy and high crystallinity. is expected to implement Specifically, it is expected that the polycyclic aromatic compound residue composition is aligned along the orientation of the carbon-based composition and grows along the crystals of the carbon-based composition, thereby realizing anisotropy and high crystallinity. Accordingly, the pitch produced by the manufacturing method according to the present invention may have a mesophase.

In step c), spun fibers are prepared by melt-spinning the pitch prepared in step b).

In the spinning step, for example, spun fibers may be produced by a spinning process in which the prepared blend dispersion is spun through a spinneret at a spinning temperature of 250 to 350 ° C. at a winding speed of 300 to 800 m / min. The uniformity and thickness of the fibers produced can be determined according to the selection of the nozzle, and it is preferable because excellent orientation and crystallinity of the liquid crystal phase of the spun fibers can be expressed.

In addition, according to one aspect of the present invention, the blend dispersion may have spinnability that can be wound at a winding speed of 300 to 800 m/min during melt spinning. Due to these characteristics, it is preferable as a precursor material for carbon fiber because it is not easily singled and can form spun fibers during spinning.

In step d), carbon fibers may be produced by carbonizing the prepared spun fibers.

According to one aspect of the present invention, the carbonization step converts the spun fibers into carbon fibers by carbonization, and corresponds to step d). Step d) may be carbonization at 800 to 3,000 ° C. in an inert gas atmosphere. Specifically, carbonization may be performed for 30 minutes to 90 minutes by raising the temperature from room temperature to 800 to 3,000 ° C. at 5 ° C. per minute, and carbonization may be performed 1 to 3 times.

The carbonization step may be carried out at different temperatures and times when proceeding over 2 to 3 times. For example, it is possible to control the physical properties of carbon fiber through the process of 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, but is not limited thereto. no.

In the case of step-by-step carbonization as described above, physical properties such as orientation or compactness of carbon fibers are excellent, which may be more preferable.

According to one aspect of the present invention, a stabilization step may be further performed before the carbonization step. The stabilization step may be performed by raising the temperature at 1 °C per minute to 280 to 320 °C in air and oxidatively stabilizing for 30 to 90 minutes to prepare an incompatible fiber. As the stabilization step is performed, the spun fiber is dehydrogenated and oxidized in an oxidizing atmosphere, whereby hydrogen atoms are separated into molecules or bonds between molecules are induced due to the combination of oxygen. At this time, the reacting oxygen atoms are evenly transferred to the inside of the spinning fiber, so that a ladder structure in which the entire spinning fiber is stable can be formed, so that it can have excellent flame resistance (stability).

In addition, in the stabilization step, low-boiling components are volatilized through a softening melt phase, some of them are thermally decomposed and released out of the system, and the remaining components are activated while undergoing cyclization, aromatization, and polycondensation is a liquid phase carbonization reaction. Through the stabilization step as described above, the polycyclic aromatic residue composition, which is a polycyclic aromatic planar molecule intercalated between the layers of the carbon-based composition in the spinning fiber, aggregates with van der Waals force as a driving force, and is stacked in parallel to each other to achieve orientation and liquid crystallinity. This can be further improved.

The stabilization step may also be performed by irradiating electromagnetic waves. The type of electromagnetic wave may be the same as the type of electromagnetic wave in step b). In the stabilization step, electromagnetic waves may be irradiated in various atmospheres, but may be specifically irradiated in an atmosphere containing air, oxygen, nitrogen, and the like. Such a stabilization step is more preferable because stabilization is possible within a short time, mechanical properties are improved while maintaining the shape of the spun fiber, and carbon fibers having excellent electrical conductivity can be manufactured as high density and high carbonization.

More specifically, the stabilization step may be performed by raising the temperature to 280 to 320 ° C. at 1 ° C. per minute using electromagnetic waves in the air and oxidatively stabilizing the fiber for 30 to 90 minutes to prepare an incompatible fiber. At this time, the output of the electromagnetic waves is automatically adjusted according to the temperature, and may be irradiated with an intensity of 300 to 15,000 W for 0.001 seconds to 600 minutes, but is not limited thereto. In addition, the basic heat treatment process and electromagnetic waves may be mixed.

The pitch produced according to the present invention will be described in detail as follows.

The pitch according to the present invention may be prepared by applying electromagnetic waves to a blend dispersion in which the polycyclic aromatic compound residue composition and the carbon-based composition are intercalated, and may be prepared by the above-described preparation method.

The pitch may be isotropic or anisotropic, and may have a high softening point. The isotropic pitch can be activated as a raw material of isotropic carbon fiber and applied to adsorbents or heat dissipators, and the anisotropic mesophase pitch can be applied to manufacturing high elasticity and high conductivity carbon fibers with high added value due to its excellent mechanical properties. can

The carbon fiber according to the present invention is described in detail as follows.

The carbon fiber according to the present invention may be carbonized after melt spinning the pitch, and may be manufactured by the above-described manufacturing method.

Carbon fibers according to a preferred aspect of the present invention may be carbon fibers having anisotropy, and more specifically, by applying electromagnetic waves to a blend dispersion in which the polycyclic aromatic compound residue composition and the carbon-based composition are intercalated, the carbon-based composition Carbon having improved mechanical properties such as high elastic modulus, excellent thermal conductivity and electrical conductivity by carbonizing mesophase pitch having anisotropy and high crystallinity prepared by polymerizing the polycyclic aromatic compound residue composition in an oriented form along the liquid crystal structure of It may be made of fibers. Preferably, the carbon-based composition is any one or two or more carbon-based materials selected from one-dimensional or two-dimensional carbon-based materials, and the polycyclic aromatic compound residue composition has an average molecular weight of 100 to 1,000 Da by MALDI-TOF. It may be a petroleum-based polycyclic aromatic compound residue composition or a coal-based polycyclic aromatic compound residue composition including an aromatic compound. Carbon fibers prepared according to the preferred combination as described above may preferably be carbon fibers having anisotropy.

As described above, according to the carbon fiber manufacturing method according to the present invention, it is possible to provide an isotropic carbon fiber pitch or a carbon fiber pitch having excellent oxidation stability and oxidation incompatibility while having a high softening point and high strength.

In addition, the carbon fiber according to the present invention can be used as a highly-oriented liquid crystal composite carbon fiber due to the formation of a liquid crystal phase as well as the effect of increasing physical properties due to the improvement of crystallinity by the carbon-based composition. The carbon fiber according to the present invention can obtain the advantages of graphene-based materials and the advantages of liquid crystal at the same time. It can exhibit various optical, dielectric, mechanical properties, etc., so the utilization of graphene-based materials can be expanded and new processes can be established.

The present invention will be described in more detail based on the following Examples and Comparative Examples. However, the following Examples and Comparative Examples are only one example for explaining the present invention in more detail, and the present invention is not limited by the following Examples and Comparative Examples.

[Experiment method]

1. Measurement of electrical conductivity of carbon fiber

The electrical conductivity of the carbon fiber in the example is measured by using CMT-SR1000N from AIT Co., Ltd., with a distance of 1 cm between the electrodes and contacting the sample thereon, and then connecting it to a measuring instrument capable of measuring current and voltage. 4-point probe measurement method was used.

2. Tensile strength

In accordance with ASTM D 638 (Standard Test Method for Tensile Properties of Plastics), specimens for measurement were made and tensile strength was measured using UTM 5982. (tensile strength [Pa] = maximum load [N] / cross-sectional area of the initial sample [㎡])

[Example 1] (Blend mixing ratio 1:0.03)

Liquid LMFD (MALDI-TOF average molecular weight 259 Da, degree of orientation 0.74) and reduced graphene oxide (rGO) were placed in a crucible at a weight ratio of 1: 0.03, and then ball milled to prepare a uniform blend dispersion. The prepared blend dispersion was irradiated with a microwave intensity of 700 W for 90 minutes to prepare pitch in a solid state. The prepared pitch had a softening point of 265.1 ° C.

The graphene mixture pitch prepared by microwave is filled in the cylinder of the spinning machine and heated. After raising the temperature to 300 ° C., it is maintained for 30 minutes to secure thermal stability and maintained at 280 ° C. for 1 hour to melt the pitch. The melted pitch was spun under conditions of 280° C. and 0.1 Mpa to obtain spun fibers. At this time, the diameter of the spinneret used was 0.5 × 0.5 mm, and the fiber spun with a nozzle having a diameter/depth ratio of 1/1 was wound up at a winding speed of up to 300 m/min.

The spun fibers obtained by melt spinning were oxidized and stabilized by raising the temperature at 1 ° C per minute under an O ₂ atmosphere while circulating air using a hot air circulation furnace and holding at 300 ° C for 1 hour, and then at 5 ° C / min to 1,000 ° C in a nitrogen atmosphere. The temperature was raised and maintained for 1 hour to prepare carbon fibers. Furthermore, in order to improve the physical properties of the manufactured carbon fiber, the temperature was raised to 2,000 ° C. at 10 ° C./min in an argon atmosphere and maintained for 1 hour to perform a graphitization process.

[Example 2] (Blend mixing ratio 1:0.05)

A blend dispersion was prepared by mixing liquid LMFD (MALDI-TOF average molecular weight 259 Da, degree of orientation 0.74) and reduced graphene oxide (rGO) at a weight ratio of 1:0.05 through a ball milling process. The prepared blend dispersion was irradiated with a microwave intensity of 700 W for 60 minutes to prepare pitch in a solid state. The prepared pitch had a softening point of 279.4 ° C.

The prepared pitch was filled in the cylinder of the spinning machine and heated. After raising the temperature to 320 ° C., the pitch was maintained for 30 minutes to secure thermal stability and maintained at 300 ° C. for 1 hour to melt the pitch. The melted pitch was spun under conditions of 300 ° C. 0.1 Mpa to obtain spun fibers. The diameter of the spinneret used at this time was 0.5 mm, and the fibers spun with a nozzle having a diameter/depth ratio of 1/1 were wound up at a winding speed of 300 m/min.

The spun fibers obtained by melt spinning were heated at 1 ° C per minute while circulating air using a hot air circulation furnace, maintained at 300 ° C for 1 hour to oxidize and stabilized, and then heated at 5 ° C / min to 1,000 ° C in a nitrogen atmosphere and heated for 1 hour. maintained to produce carbon fibers. Furthermore, in order to improve the physical properties of the manufactured carbon fiber, the temperature was raised to 2,000 ° C. at 10 ° C./min in an argon atmosphere and maintained for 1 hour to perform a graphitization process.

[Example 3] (Blend mixing ratio 1:0.01)

A blend dispersion was prepared by mixing liquid LMFD (MALDI-TOF average molecular weight 259 Da, orientation degree 0.74) and reduced graphene oxide (rGO) at a weight ratio of 1:0.01 through a ball milling process. The prepared blend dispersion was irradiated with a microwave intensity of 700 W for 120 minutes to prepare pitch in a solid state. The prepared pitch had a softening point of 227.6 ° C.

The prepared pitch was filled in the cylinder of the spinning machine and heated, after heating to 270 ° C., maintained for 30 minutes to ensure thermal stability, and maintained at 260 ° C. for 1 hour to melt the pitch. The melted pitch was spun under conditions of 260 ° C. 0.1 Mpa to obtain spun fibers. The diameter of the spinneret used at this time was 0.5 mm, and the fibers spun with a nozzle having a diameter/depth ratio of 1/1 were wound up at a winding speed of 300 m/min.

The spun fibers obtained by melt spinning were heated at 1 ° C per minute while circulating air using a hot air circulation furnace, maintained at 300 ° C for 1 hour to oxidize and stabilized, and then heated at 5 ° C / min to 1,000 ° C in a nitrogen atmosphere and heated for 1 hour. maintained to produce carbon fibers. Furthermore, in order to improve the physical properties of the manufactured carbon fiber, the temperature was raised to 2,000 ° C. at 10 ° C./min in an argon atmosphere and maintained for 1 hour to perform a graphitization process.

[Example 4] (Blend mixing ratio 1:0.1)

A blend dispersion was prepared by mixing liquid LMFD (MALDI-TOF average molecular weight: 259 Da, degree of orientation: 0.74) and reduced graphene oxide (rGO) at a weight ratio of 1:0.1. The prepared blend dispersion was irradiated with a microwave intensity of 700 W for 30 minutes to prepare pitch in a solid state. The prepared pitch had a softening point of 323.6 ° C. The prepared pitch was filled in the cylinder of the spinning machine and heated. After raising the temperature to 340 ° C., the pitch was maintained for 30 minutes to secure thermal stability and maintained at 320 ° C. for 1 hour to melt the pitch. The melted pitch was spun under conditions of 320 ° C. 0.1 Mpa to obtain spun fibers. At this time, the diameter of the spinneret used was 0.5 mm, and the fibers spun with a nozzle having a diameter/depth ratio of 1/1 were wound up at a winding speed of 300 m/min.

The spun fibers obtained by melt spinning were heated at 1 ° C per minute while circulating air using a hot air circulation furnace, maintained at 300 ° C for 1 hour to oxidize and stabilized, and then heated at 5 ° C / min to 1,000 ° C in a nitrogen atmosphere and heated for 1 hour. maintained to produce carbon fibers. Furthermore, in order to improve the physical properties of the manufactured carbon fiber, the temperature was raised to 2,000 ° C. at 10 ° C./min in an argon atmosphere and maintained for 1 hour to perform a graphitization process.

[Example 5]

Liquid LMFD (MALDI-TOF average molecular weight 259 Da, degree of orientation 0.74) and reduced graphene oxide (rGO) were placed in a crucible at a weight ratio of 1: 0.03, and then ball milled to prepare a uniform blend dispersion. The prepared blend dispersion was heated up to 300 °C at a rate of 5 °C per minute under a nitrogen atmosphere using a microwave reactor, and maintained for 30 minutes. The average intensity of the applied microwaves at this time was 1000 W. A pitch in the solid state having a softening point of 246.4° C. was prepared. At this time, the applied W was automatically adjusted according to the temperature sensor of the microwave reactor.

The graphene mixture pitch prepared by microwave was filled in the cylinder of the spinning machine and heated. After raising the temperature to 280 ° C., the pitch was maintained for 30 minutes to secure thermal stability and maintained at 270 ° C. for 1 hour to melt the pitch. The melted pitch was spun under conditions of 270 ° C. 0.1 Mpa to obtain spun fibers. The diameter of the spinneret used at this time was 0.5 × 0.5 mm, and the spun fibers were wound up at a winding speed of 300 m/min.

The spun fibers obtained by melt spinning were heated at 1 ° C per minute while circulating air using a hot air circulation furnace, maintained at 300 ° C for 1 hour to oxidize and stabilized, and then heated at 5 ° C / min to 1,000 ° C in a nitrogen atmosphere and heated for 1 hour. maintained to produce carbon fibers. Furthermore, in order to improve the physical properties of the manufactured carbon fiber, the temperature was raised to 2,000 ° C. at 10 ° C./min in an argon atmosphere and maintained for 1 hour to perform a graphitization process.

[Comparative Example 1]

A blend dispersion was prepared by mixing liquid LMFD (MALDI-TOF average molecular weight: 259 Da, degree of orientation: 0.74) and reduced graphene oxide (rGO) at a weight ratio of 1:0.05. The prepared blend dispersion was heated up to 300 °C at 10 °C/min, maintained at 300 °C for 3 hours, and then cooled naturally to prepare a pitch in a solid state. In the case of the prepared pitch, it had a softening point of 195.7 ° C. or higher.

The prepared pitch was filled in the cylinder of the spinning machine and heated. After raising the temperature to 250 ° C., the pitch was maintained for 25 minutes to secure thermal stability and maintained at 230 ° C. for 1 hour to melt the pitch. The melted pitch was spun under conditions of 230 ° C. 0.1 Mpa to obtain spun fibers. At this time, the diameter of the spinneret used was 0.5 mm, and the fibers spun with a nozzle having a diameter/depth ratio of 1/1 were wound up at a winding speed of up to 50 m/min.

The spun fibers obtained by melt spinning were oxidized and stabilized by raising the temperature at 1 ° C. per minute while circulating air using a hot air circulation furnace and holding at 300 ° C. for 1 hour, but the fibers melted during the heating process.

[Comparative Example 2]

A blend dispersion was prepared only with liquid LMFD (MALDI-TOF average molecular weight: 259 Da, degree of aromatization: 0.74). The prepared blend dispersion was irradiated with a microwave intensity of 700 W for a total of 3 hours, but solid pitch was not produced.

Table 1 shows the manufacturing conditions and physical properties of the carbon fibers of Examples 1 to 4 and Comparative Examples 1 and 2.

carbon-based composition Blend Dispersion Weight Ratio microwave irradiation
(Unit: W) irradiation time
(unit: minute) pitch softening point
(Unit: ℃) pitch crystallinity Radiation or not Example 1 rGO 1:0.03 700 90 minutes 265.1 anisotropy possible Example 2 rGO 1:0.05 700 60 minutes 279.4 anisotropy possible Example 3 rGO 1:0.001 700 120 minutes 227.6 anisotropy possible Example 4 rGO 1:0.1 700 30 minutes 323.6 anisotropy possible Example 5 rGO 1:0.03 1000 20 minutes 246.4 anisotropy possible Comparative Example 1 rGO 1:0.05 - - 195.7 anisotropy possible Comparative Example 2 - - 700 180 minutes < 100 isotropic impossible

As can be seen in Examples 1 to 5 of Table 1, it can be seen that the pitch has a high softening point of 220 ° C. or more, and also has anisotropy.

The crystallinity of pitch varies from isotropic to anisotropic as the crystal plane of LMFD is oriented along the crystal plane around reduced graphene oxide (rGO), as shown in FIG. 2 (d) showing the SEM of the cross section of the carbon fiber prepared in Example 1. , and it is judged to be the same as the crystal of reduced graphene oxide.

Also, unlike Comparative Example 1, Examples 1 to 5 were able to produce pitch within a short time. In the case of Comparative Example 2 in which the carbon-based composition was not used, it was found that the pitch crystallinity was isotropic and the pitch could not be formed under conditions where spinning was possible.

Table 2 below shows the electrical conductivity and tensile strength of the carbon fibers of Examples 1 to 4 and Comparative Examples 1 and 2.

Electrical conductivity (σ)
(Unit: S/m) tensile strength
(Unit: GPa) Example 1 109,500 1.15 Example 2 121,200 1.02 Example 3 102,000 0.95 Example 4 131,000 0.83 Example 5 114,000 1.18 Comparative Example 1 - - Comparative Example 2 - -

As shown in Table 2, it was confirmed that the carbon fibers of Examples 1 to 5 had excellent electrical conductivity and tensile strength.

That is, the carbon fiber manufacturing method of the present invention utilizes LMFD (Low-Molecular weight Fluidized Catalytic Cracking-Decant Oil), which is highly volatile as a polycyclic aromatic compound residue composition, to produce high added value with anisotropy and excellent electrical conductivity and tensile strength. It was confirmed that the material could be converted to carbon fiber.

As described above, the present invention has been described by specific details and limited embodiments and drawings, but this is only provided to help a more general understanding of the present invention, the present invention is not limited to the above embodiments, and the present invention Those skilled in the art can make various modifications and variations from these descriptions.

Therefore, the spirit of the present invention should not be limited to the described embodiments, and not only the claims to be described later, but also all modifications equivalent or equivalent to the claims will be said to belong to the scope of the present invention.

Claims (13)

a) A polycyclic aromatic compound residue composition containing a polycyclic aromatic compound and a carbon-based composition containing a one-dimensional or two-dimensional carbon-based material are mixed to obtain a blend dispersion in which the polycyclic aromatic compound residue composition and the carbon-based composition are intercalated manufacturing;
b) preparing pitch by applying electromagnetic waves to the blend dispersion;
c) melt-spinning the pitch to obtain spun fibers; and
d) carbonizing the spun fibers to obtain carbon fibers;
Including,
The pitch is an anisotropic pitch having a softening point of 150 to 370 ° C. and an average molecular weight of 300 to 2,000 Da. Method for producing carbon fibers. According to claim 1,
The polycyclic aromatic compound residue composition comprises petroleum-based polycyclic aromatic compound residue or coal-based polycyclic aromatic compound residue. According to claim 1,
The polycyclic aromatic compound residue composition comprises a polycyclic aromatic compound having an average molecular weight of 10 to 1,000 Da by MALDI-TOF. According to claim 1,
The polycyclic aromatic compound residue composition is a low-molecular weight fluidized catalytic cracking-decant oil (LMFD) method for producing carbon fiber. According to claim 1,
The carbon-based composition includes any one or two or more one-dimensional carbon-based materials selected from the group consisting of single-walled carbon nanotubes, multi-walled carbon nanotubes, graphene nanoribbons, carbon nanofibers, and carbon nanowires. Manufacturing method of carbon fiber. According to claim 1,
Wherein the carbon-based composition comprises any one or two or more two-dimensional carbon-based materials selected from the group consisting of graphene, graphene oxide (GO), and reduced graphene oxide (rGO). According to claim 1,
The blend dispersion comprises the carbon-based composition and the residue composition of the polycyclic aromatic compound in a weight ratio of 1: 0.01 to 1: 0.2. According to claim 1,
The electromagnetic waves include carbon fibers including any one selected from the group consisting of gamma rays, X-rays, visible rays, near infrared rays (NIR), infrared rays, ultraviolet rays, microwaves, microwaves, ultra-short waves, short waves, medium waves, long waves, low frequencies, high frequencies, and ultra-high frequencies. Manufacturing method of. According to claim 1,
The intercalated blend dispersion is a liquid crystal blend dispersion method for producing carbon fibers. According to claim 1,
In step b), the electromagnetic waves are irradiated with an intensity of 300 to 15,000 W and 0.001 seconds to 600 minutes. delete According to claim 1,
The manufacturing method of carbon fiber further comprising the step of stabilizing by irradiating electromagnetic waves after step c). Anisotropic pitch having a softening point of 150 to 370 °C and an average molecular weight of 300 to 2,000 Da prepared by applying electromagnetic waves to a blend dispersion in which a polycyclic aromatic compound residue composition and a carbon-based composition are intercalated is carbonized after melt spinning. .

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