KR101201682B1 - Noble pitch precursors used for preparations of carbon fiber, carbon nano-fibers and carbon materials including the carbon nano-fibers therefrom - Google Patents

Abstract

The present invention relates to carbon nanofibers, and more particularly, novel pitch having physical properties suitable for use in the production of carbon nanofibers having desired properties devised by focusing on the properties of carbon nanofibers produced according to the physical properties of the pitch. The present invention relates to a carbon nanofiber and a carbon material including the carbon nanofiber, which is controlled to have a desired physical property by using a polymer, the novel pitch polymer.

Description

Noble pitch precursors used for preparations of carbon fiber, carbon nano-fibers and carbon materials, including high molecular weight novel pitch polymers used for the production of carbon nanofibers, carbon nanofibers using the pitch polymer, and carbon nanofibers the carbon nano-fibers therefrom}

The present invention relates to carbon nanofibers, and more particularly, a novel pitch polymer having physical properties suitable for use in the production of carbon nanofibers having desired properties, with the focus on the properties of carbon nanofibers produced according to the physical properties of the pitch, The present invention relates to a carbon nanofiber and a carbon material including the carbon nanofiber prepared by controlling to have desired physical properties using the novel pitch polymer.

 Carbon fibers or activated carbon fibers (ACFs) can be classified into polyacrylonitrile (PAN), pitch, and phenol based rayon based on starting materials. In general, pitch-based fibers are produced by pitch spinning fibers by melt spinning or melt-blown method, and then stabilized in an oxidizing gas atmosphere and carbonized under an inert gas atmosphere. To prepare.

Pitch is composed of petroleum residue and coal tar. It is mainly composed of aromatic structure and has the molecular weight of oligomer. Its strength is maintained even after heat treatment in the tensionless state, and its activation property is superior to that of other polymer materials. (A) Table 1 showing (800 ° C, 30 min)], (a) electron micrograph of the web carbonized at 1000 ° C by electrospinning, and (b) electrical conductivity for each raw material (1000 ° C, 1 hour carbonization, PAN, Polyacrylonitrile; PI, Polyimide; PBI, Polybenzimidazol) as shown in Figure 1 shows a high yield and a 25 times better electrical conductivity after the carbonization process.

In Korean Patent Application No. 10-2003-0002759, "In the method for producing isotropic activated carbon fiber nanoweb by electrospinning using petroleum-based isotropic pitch solution as a precursor, the nanoweb prepared by the electrostatic spinning is oxidative Stabilization process in the range of 250 ~ 300 ℃ in gas atmosphere, carbonization process in the range of 800 ~ 900 ℃ in inert atmosphere using argon (Ar) gas, 700 using water vapor It proposes a method for producing an isotropic activated carbon fiber nanoweb, characterized in that it comprises an activation process carried out in the range of ~ 800 ℃ "that is, the production of pitch-based carbon nanofibers by the electrospinning method. The material that can produce carbon fiber by using it has excellent solubility, so that the viscosity of the fiber can be maintained. Rather than to be decomposed when heat-treated at a high temperature should set an attribute that generates an aromatic hydrocarbon while. In particular, in order to electrospin, the molecular weight must be large enough so that there is no cutting phenomenon due to surface tension and the viscosity must be low enough to be suitable for spinning. Manufacturing such pitches remains an important challenge.

In general, the electrospun nanofibers have a short fiber length and thus cannot be heat treated in a tensioned state, so that the strength and tensile modulus of elasticity are not comparable to those of the filament carbon fiber heat treated in the tensioned state.

To solve this problem, if the composite is formed in the pitch and molecular state having a plate-like structure, it is possible to prevent the shrinkage of the PAN polymer by the plate-like pitch molecule, so that the pitch molecule and the PAN molecule form a molecular complex to form carbon fiber. If manufactured, composite carbon nanofibers with high strength and high tensile modulus may be possible.

Since the composite carbon nanofibers, such as the pitch system or the pitch / PAN system, are determined according to the properties of the pitch, which is a precursor, there is a need to develop a suitable pitch polymer for producing nano carbon nanofibers having a desired function. It became.

The present inventors have completed the present invention by developing a pitch polymer having a characteristic expressing the most appropriate function according to the characteristics of the desired carbon nanofibers as a result of research efforts to solve this problem.

Accordingly, it is an object of the present invention to provide a novel pitch polymer that can be best used for the desired properties of carbon nanofibers in the production of carbon nanofibers.

Another object of the present invention is to control the size and depth of the pores formed by using a high molecular weight and a high molecular weight pitch polymer, so that a plurality of ultra-micropores formed porous carbon nanofibers and porous carbon nanofibers By using the properties to provide a porous carbon material exhibiting excellent properties such as high energy density, high power density, high adsorption.

The objects of the present invention are not limited to the above-mentioned objects, and other objects not mentioned can be clearly understood by those skilled in the art from the following description.

In order to achieve the above object of the present invention, the present invention is made of a repeating unit having the following structural formula 2, and provides a high molecular weight pitch polymer, characterized in that the molecular weight is 1000 to 5000.

[Formula 2]

In a preferred embodiment, the high molecular weight pitch polymer solution is mixed with the polymer solution to form a separate biphasic solution.

In a preferred embodiment, the polymer solution comprises at least one polymer selected from the group consisting of PAN, Polyimide, Poybenzimidazole, Cellulose, Kevlar.

In another aspect, the present invention provides a porous carbon nanofiber, characterized in that the high molecular weight pitch polymer of any one of the above-described dissolved or blended with the PAN is formed by electrospinning the dissolved spinning solution.

In a preferred embodiment, in the case of the porous carbon nanofibers formed by electrospinning the spinning solution in which the high molecular weight pitch polymer and PAN are dissolved, pores having a diameter in the range of 0.5 to 1.4 nm are formed. Is 80% or more, and the porosity of 1.2 nm is 20% or less.

In addition, the present invention provides a porous carbon material comprising the porous carbon nanofibers described above.

In a preferred embodiment, the porous carbon material is used as at least one of an electric double layer capacitor electrode, a fuel cell electrode, a diffusion layer of the fuel cell, a hydrophilic selective filter.

The present invention has the following excellent effects.

First, according to the present invention can provide a novel pitch polymer that can be most suited to the desired properties of carbon nanofibers in the production of carbon nanofibers.

In addition, according to the present invention, the polymer solution and the pitch polymer which is phase-separated while having a high molecular weight and high solubility are mixed to separate the skin and the core layer, and the pore size and depth can be controlled according to the thickness of the skin layer. a plurality of ultra-micropore (ultramicropore) is formed of a porous carbon nanofibers, and a high energy density by using the characteristics of the porous carbon pores formed in the nano-fiber, high-high power density, is to provide a porous carbon material which exhibits excellent properties such as separation adsorption Can be.

1 is a (a) electron micrograph of the web carbonized at 1000 ℃ by electrospinning the pitch solution and (b) electrical conductivity graph (1000 ℃, 1 hour carbonization, PAN, Polyacrylonitrile; PI, Polyimide; PBI, Polybenzimidazol) )
Figure 2 is a schematic diagram showing the development of the use of carbon nanofibers and carbon materials prepared using the novel pitch polymer of the present invention,
Figure 3a is a graph showing the results of ¹³ C nuclear magnetic resonance spectroscopy (NMR) analysis of the low molecular weight pitch polymer of the novel pitch polymer of the present invention,
Figure 3b is a graph showing the results of ¹³ C nuclear magnetic resonance spectroscopy (NMR) analysis of high molecular weight pitch polymer of the novel pitch polymer of the present invention,
Figure 4a is a graph showing the results of ¹ H MAS nuclear magnetic resonance spectroscopy (NMR) analysis of low molecular weight pitch polymer of the novel pitch polymer of the present invention,
Figure 4b is a graph showing the results of ¹ H MAS nuclear magnetic resonance spectroscopy (NMR) analysis of high molecular weight pitch polymer of the novel pitch polymer of the present invention,
5A is an average molecular structure diagram of a monomer which is a repeating unit of a low molecular weight pitch polymer of the novel pitch polymer of the present invention;
5B is an average molecular structure diagram of a monomer which is a repeating unit of a high molecular weight pitch polymer of the novel pitch polymer of the present invention;
6 is an infrared absorption spectral distribution graph (FT-IR) of the novel pitch polymers of the present invention,
FIG. 7A is a graph showing the solution electrical conductivity (16.5 ° C.) of the physical properties of the novel pitch polymer solutions of the present invention. FIG.
FIG. 7B is a graph showing solution viscosity (19.5 ° C.) in the physical properties of the novel pitch polymer solutions of the present invention. FIG.
8 is a schematic flowchart illustrating a method of manufacturing carbon nanofibers by electrospinning a spinning solution prepared using the novel pitch polymers of the present invention and a method of manufacturing a supercapacitor electrode using the same;
9 is a phase diagram of a phase balance diagram of a mixed solution of a novel pitch polymer solution and a PAN solution of the present invention;
10 is a pore distribution graph of carbon fibers prepared using a high molecular weight novel pitch polymer among the novel pitch polymers of the present invention;
11 is an electron micrograph of the carbon fiber prepared by electrospinning using the novel pitch polymer of the present invention,
12 is an electron transmission electron microscope (TEM) photograph of the novel pitch polymers / PAN carbon nanofibers of the present invention;
FIG. 13 is a graph of Ragon plot of low molecular weight pitch polymer / PAN carbon nanofiber electrode according to activation temperature in manufacturing carbon fiber using low molecular weight pitch polymer among novel pitch polymers of the present invention.
FIG. 14 is a Ragon plot graph of a high molecular weight pitch polymer / PAN carbon nanofiber electrode according to a high molecular weight pitch polymer concentration (PCF) in the production of carbon fibers using the high molecular weight pitch polymer of the novel pitch polymer of the present invention.

Although the terms used in the present invention have been selected as general terms that are widely used at present, there are some terms selected arbitrarily by the applicant in a specific case. In this case, the meaning described or used in the detailed description part of the invention The meaning must be grasped.

Hereinafter, with reference to the preferred embodiments disclosed in the accompanying drawings will be described in detail the technical configuration of the present invention.

However, the present invention is not limited to the embodiments described herein but may be embodied in other forms. Like reference numerals used to describe the present invention throughout the specification denote like elements.

The technical feature of the present invention is to provide two kinds of novel pitch polymers having the most suitable properties for use according to the properties of the desired carbon nanofibers, low molecular weight pitch polymer and high molecular weight pitch polymer according to molecular weight and solubility characteristics. It was divided as follows.

 First, the low molecular weight pitch polymer of the present invention is composed of repeating units having the following Structural Formula 1, and has a molecular weight of 300 to 1500. The low molecular weight pitch polymer solution is mixed with the polymer solution to form a single phase solution and thus has a high solubility.

[Formula 1]

In addition, the high molecular weight pitch polymer of the present invention is composed of repeating units having the following Structural Formula 2, and has a molecular weight of 1000 to 5000, wherein the high molecular weight pitch polymer solution is mixed with the polymer solution to form a separated double phase solution. .

[Formula 2]

Here, the polymer solution preferably contains any one or more polymers selected from the group consisting of PAN, Polyimide, Poybenzimidazole, Cellulose, and Kevlar.

Electrospinning is carried out using only a solution in which two kinds of petroleum pitches, a low molecular weight pitch polymer (hereinafter referred to as "pitch 1") and a high molecular weight pitch polymer (hereinafter referred to as "pitch 2") in a solvent, especially THF, is used as a spinning solution. Carbon fiber was prepared by electrospinning the spinning solution prepared by mixing the solution and PAN solution, and the characteristics of each carbon fiber were analyzed as in the following experimental examples.

As will be described later, since the spinning solution containing pitch 1 has a monophase, carbon fibers formed by electrospinning have high strength and high tensile properties and are suitable for use as a high strength carbon material. Particularly, in the case of high-strength carbon nanofibers formed by electrospinning a spinning solution in which pitch 1 and PAN are dissolved, pores having a diameter in the range of 0.8 to 1.6 nm are formed. 1.2 nm pores are 60% or more of the total pores, and 1.4 nm. The pore of is 20% or less, and the pore of 1.4 nm or more is 20% or less.

In addition, since the spinning solution containing pitch 2 is formed in a separate double phase, the carbon fiber formed by the electrospinning, the depth of the pore is determined according to the thickness of the skin layer, so that many ultramicropores having a small depth and a large specific surface area are formed. Since it has a porous property, it forms a porous carbon material suitable for use as a supercapacitor or a high performance adsorptive separation material having a high energy density and a power density at the same time.

That is, as shown in FIG. 2, when the carbon nanofibers in which pitch 2 and PAN are composed of skins and cores are prepared using a phase in which pitch 2 and PAN are separated, the electrical conductivity of the pitch system is excellent, and low porosity and large The specific surface area can be used for electrodes of supercapacitors that can simultaneously improve power density and energy density. When the pitch-based carbon fiber layer having hydrophobic properties surrounds the layer of polar PAN-based carbon fiber, hydrophilic or hydrophobic solvents or gases can be selectively separated or stored.

Particularly, in the case of porous carbon nanofibers formed by electrospinning a spinning solution in which pitch 2 and PAN are dissolved, pores having a diameter in the range of 0.5 to 1.4 nm are formed, and 0.5 nm pores are 80% or more of the total pores, and 1.2 The pore of nm is 20% or less.

Experimental Example 1

The monomer molecular structure of the low molecular weight pitch polymer (hereinafter, "pitch 1") and the high molecular weight pitch polymer (hereinafter, "pitch 2") obtained from the naphtha cracking process residue oil was determined as follows. .

In other words, to obtain information about the carbon and hydrogen atoms in the molecules of the pitch 1 and 2 of the present invention using nuclear magnetic resonance spectroscopy (NMR) to more accurately understand the structure of each pitch and the results are shown in Figures 3a, 3b , 4a and 4b.

The ¹³ C solid NMR shown in FIGS. 3A and 3B shows broad peaks of aliphatic and aromatic carbon in the range of δ 0-50 and 100-150 ppm, respectively. At δ100-150 ppm where aromatic carbon appears, pitch 1 shows a single peak, whereas in NMR of pitch 2, it can be expected that the pitch 2 is bound to aromatic other functional groups other than hydrogen through the splitting of the peak. In addition, in the range of aliphatic carbon peaks δ0 to 50, pitch 2 has a relatively larger area ratio than pitch 1, which can be expected to have more aliphatic hydrocarbons in pitch 2, which is consistent with the IR results described below. Can be.

In the ¹ H solid NMR of FIGS. 4A and 4B, pitch 2 is separated from peaks of aliphatic methyl hydrogen and aromatic hydrogen in the range of δ0-5 and δ5-10 ppm, whereas pitch 1 is a broad overlapping line at δ0-10 ppm. Can be observed. Pitch 1 also peaks toward δ5-10 ppm, which can be expected to have more aromatic hydrogen.

Based on the FT-IR and NMR data, the average molecular structure of the monomers forming the repeating units having pitches 1 and 2 was determined and shown in FIGS. 5A and 5B, respectively. An important difference between the pitch 1 and 2 monomer molecular structures is that pitch B has a large molecular weight compared to pitch 1 while containing many functional groups such as aliphatic hydrocarbons and hydroxyl groups in the molecule.

That is, the splitting of peaks in NMR is called spin-spin splitting, which occurs due to the presence of unequal neighboring protons or adjacent protons. Since pitch 2 contains more functional groups than pitch 1, it exhibits relatively weak π-π stacking interaction due to its low orientation. From these results, pitch 2 has a low anisotropy effect and less dipolar interaction between the nuclear spins, so that the peak splitting can be clearly observed in ¹ H solid NMR.

Experimental Example 2

Molecular weight, solubility, and elemental analysis of the pitch 1 and the pitch 2 of the present invention were performed in Tables 2 and 3.

Pitch ^a M _w ^b M _n ^c PDI ( M _w / M _n ) ^d Pitch 1 556 488 1.14 Pitch 2 2380 (1000-5000) 1982 1.20

a, part dissolved in THF; b, weight average molecular weight; c, number average molecular weight; d, PDI (polydispersity): polydispersity index, molecular weight distribution

pitch Softening point ^a Solubility (%) ^b Elemental analysis   HI BS BI-PS PI   C H N O Pitch 1 256  97.2 54.4 44.9 0.72  93.82 5.22 0.13 0.73 Pitch 2 292  96.7 63.8 36.2 0  92.74 5.83 0.02 1.41

a, measured by Mettler method; HI, Hexane insoluble; BS, Benzene dissolved fraction; BI-PS, Benzene Insoluble-Pyridine Dissolved; PI, Pyridine Insoluble

As shown in Table 2, the weight average molecular weight of the part dissolved in THF was confirmed by gel permeation chromatography (GPC), indicating that pitch 2 was 4 times larger than pitch 1.

Thus, Table 2, which is the result of analyzing the molecular weight of pitch 1 and pitch 2 and Table 3, which is the result of analyzing solubility, shows that pitch 2 has a higher weight average molecular weight than pitch 1, but pitch 1 has a high content of hydrogen and oxygen, It can be seen that the solubility is higher than the pitch 2.

Experimental Example 3

Infrared absorption spectra (FT-IR) of pitches 1 and 2 of the present invention were analyzed and the results are shown in FIG. 6.

As shown in the infrared absorption spectra (FT-IR) graph of FIG. 6, it can be seen that pitch 1 and pitch 2 both have similar functional groups. In particular, the stretching vibration of the aliphatic hydrocarbon CH bonds appearing at 3000-2700 cm ⁻¹ can predict that the pitch 2 has more aliphatic hydrocarbon structure due to the stronger pitch 2 than the pitch 1.

Experimental Example 4

Characterization of the electrospinning spinning solution dissolved alone or together with PAN of the pitch 1 and the pitch 2 of the present invention and the result is the solution electrical conductivity (16.5 ℃) of the physical properties of the solution is shown in Figure 7a, solution viscosity ( 19.5 ° C.) is shown in FIG. 7B. In other words, pitch 1 and 2 were either spun alone or mixed with polyacrylonitrile (PAN) and electrospun, and the conductivity and viscosity of the solution suitable for spinning were investigated to prepare carbon fibers through heat treatment.

As a result of the experiment, as shown in FIGS. 7A and 7B, when only the pitch solution is spun alone, pitch 1 has a higher degree of directionality through IR and NMR, so that molecules of pitch 1 are more easily stacked, so that solution conductivity is higher than that of pitch 2 solution. Larger, solution viscosity showed higher viscosity because of higher molecular weight of pitch 2.

In addition, it can be seen that the conductivity and viscosity of the PAN / pitch mixed solution also show the same tendency as the pitch solution. On the other hand, after electrospinning the PAN / pitch mixed solution blended with PAN and pitch solution, and oxidative stabilization and carbonization to produce carbon fiber, each of the disadvantages that occur when electrospinning PAN and pitch alone, The high power and high capacity of the double layer capacitor can be expressed simultaneously.

Experimental Example 5

As shown in FIG. 8, carbon nanofibers may be prepared by electrospinning pitch 1 and pitch 2 spinning solutions or PAN / pitch 1 and PAN / pitch 2 spinning solutions, and a supercapacitor electrode may be manufactured using the same. In this experimental example, the 40wt.% Pitch / THF solution and the pitch (1, 2) / THF / DMF (8/2) mixed solution were electrospun or the PAN and pitch 1, 2 were dissolved in the mixed solution of THF and DMF. The phase equilibrium of the PAN / pitch mixed solution, a spinning solution prepared by mixing 50:50 wt% and 70:30 wt%, is shown in FIG. 9.

That is, insoluble and dissolved portions were separated in the mixed solution of THF and DMF, and the amount of each PAN, pitch, and solvent was measured to prepare a phase balance. Phase A is a homogeneous solution, Phase B is a biphasic solution, Phase C is a mixture of solid solute and solvent, and the grayscale portion in Phase B is highly radioactive. As shown in FIG. 9, pitch 2 has a wider two-phase solution portion and a gray-filled portion of phase B than pitch 1, and phase separation easily occurs between pitch and PAN, and the difference in pitch and PAN concentration in the phase is large. At the same time it shows a larger area that can be radiated.

Experimental Example 6

Pitch or PNA / pitch spun fiber obtained by electrospinning the spinning solution prepared in Experimental Example 5 was supplied with a compressed air at a flow rate of 5 to 20 mL per minute using a hot air circulation ,, and 200 ~ at a temperature rising rate of 1 ℃ per minute. Stabilization was carried out at 300 ° C. for 1 hour to obtain a single pitch or PAN / pitch flame resistant fiber.

Thereafter, steam was supplied to the carrier gas nitrogen to develop pores, and PAN / pitch 1-activated fibers were manufactured through an activation process at a temperature of 700 to 900 ° C. In addition, the PAN / pitch 2 flame resistant fiber after the stabilization process was carbonized at a temperature of 700 ~ 1500 ℃ under an inert gas (N ₂ , Ar gas) atmosphere to prepare a PAN / pitch 2 carbon fiber. The specific surface area and the average diameter of the average pores of the prepared fibers were analyzed and the results are shown in Tables 4 and 5.

The resultant values shown in Table 4 are the average diameters of the specific surface area and the average pore of the PAN / pitch 1 activated fiber according to the activation temperature, and the resultant values shown in Table 5 indicate the activation of PAN / Pitch 2 according to the pitch content in the spinning solution. It is the average diameter of a specific surface area and an average pore before following.

Activation Temperature (℃) BET surface area
(m ² / g) Pore volume
(cm < ³ > / g) Average pore size
(A) 700 722.9 0.3244 17.9 800 1220.2 0.7674 18.9 900 1724.8 1.1138 25.8

Sample ID BET surface area
(m ² / g) Pore volume
(cm < ³ > / g) Average pore size
(A) PANHP73-PC20-T293 963.28 0.3788 15.731 PANHP73-PC30-T293 887.23 0.3483 15.704 PANHP73-PC40-T293 820.30 0.3350 15.780 PANHP73-PC50-T293 692.93 0.2714 15.667 PANHP55-PC40-T293 555.15 0.2188 15.762 PAN-T293 708.46 0.2765 15.561

Experimental Example 7

The pore distribution of carbon fibers prepared by electrospinning of PAN, pitch 2, PAN / pitch 2-73-PC20 or 50 (PC: pitch concentration in THF) solution was analyzed and shown in FIG. 10.

It can be seen from the graph shown in FIG. 10 that most of the pores formed in the carbon fiber are composed of ultramicropores of 1.6 nm or less. In particular, PAN / Pitch 2-73-PC20 based carbon fiber shows 80% of total porosity near 0.6 nm, while PAN based carbon fiber shows most pore distribution at 1.4 nm. Therefore, it can be seen that the size distribution of the pores is clearly changed according to the pitch composition component, and the PAN / Pitch 2-73-PC20-based carbon fibers form 0.6 nm monodisperse pores and have the largest specific surface area. In general, ultramicropores of less than 0.7 nm are capable of adsorption and desorption of selective ions such as molecular sieve effects. Therefore, PAN / pitch-based carbon fiber composed of ultramicropores will exhibit very large electrode characteristics when used as a supercapacitor electrode because the solvated ions of aqueous solution or organic electrolyte have a size of 0.8 ~ 1.0 nm. It is expected.

Experimental Example 8

Pitch 1 and 20,000 carbon fibers and PAN / pitch composite carbon fibers prepared by electrospinning were observed under an electron microscope (SEM) and an electron transmission electron microscope (TEM), and the photographs are shown in FIGS. 11 and 12, respectively. . In FIG. 11, (a) is a photograph of carbon nanofibers using pitch 1, (b) is a photograph of carbon nanofibers using pitch 2, and (c) is carbon nanofibers using PAN / pitch 1-70 / 30. (D) is a photograph of carbon nanofibers using PAN / Pitch 2-70 / 30. In FIG. 12, (a) is a picture of carbon nanofibers using PAN / pitch 1-70 / 30, and (b) is a picture of carbon nanofibers using PAN / pitch 2-70 / 30.

It can be seen from FIG. 11 that the PAN / pitch composite carbon fiber has a smaller fiber diameter than that of the pitch 1 and 20,000 carbon fibers and that the PAN / pitch 2 has a smaller fiber diameter than the PAN / pitch 1.

In the electron transmission electron microscopy (TEM) photograph of the PAN / pitch graphitized fiber shown in FIG. 12, phase separation cannot be observed in PAN / pitch 1-70 / 30, but two PAN / pitch 2-70 / 30 are observed. It can be observed that the phases are separated. In addition, the component analysis showed nitrogen in the core of the flame resistant fiber and only carbon in the skin. The results show that the PAN containing nitrogen is located in the core part and the skin-core structure in which the pitch part is located in the skin part, and the phase separation of the crystalline layer on the sheath and the low crystal layer on the core. It was confirmed experimentally that was increased as the concentration of pitch increased. In this case, when the pitch-based carbon fiber layer having hydrophobic properties surrounds the layer of polar PAN-based carbon fiber, hydrophilic or hydrophobic solvents or gases can be selectively separated or stored.

Experimental Example 9

Ragon graphs showing the results of measuring the electric double buffer capacitors of PAN / Pitch 1 carbon nanofibers prepared as Table 4 and PAN / Pitch 2 carbon nanofibers prepared as Table 5 are shown in FIGS. 13 and 14, respectively. It was. As the electrolyte, KOH, which is an aqueous solution electrolyte, was used, and the charge / discharge voltage ranged from 0 to 1V. The energy and power densities of PAN / pitch carbon fiber capacitors were measured in aqueous electrolyte. At this time, in Figure 13 (a) is 700 ℃, (b) is 800 ℃, (c) means PAN / Pitch 1 carbon nanofibers formed at 900 ℃.

13 and 14, the PAN / pitch 2 carbon nanofibers have higher energy density 9.0 to 15 Wh / kg and power density 400 to 100,000 W / kg than the PAN / pitch 1 activated fiber, respectively, without undergoing an activation process to increase porosity. I can see it.

The above experimental results are to select the novel pitch polymers of the present invention according to the desired carbon nanofiber properties, and to control the microstructure and the size and specific surface area of the carbon nanofibers using the selected pitch polymer to prepare a material suitable for the purpose. It can be seen that.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, Various changes and modifications will be possible.

Claims (7)

A high molecular weight pitch polymer comprising a repeating unit having the following Structural Formula 2 and having a molecular weight of 1000 to 5000.
[Formula 2]

The method of claim 1,
The high molecular weight pitch polymer solution is mixed with the high molecular weight solution to form a high molecular weight pitch polymer, characterized in that the separated solution.
The method of claim 2,
The polymer solution is a high molecular weight pitch polymer, characterized in that it comprises any one or more polymers selected from the group consisting of PAN, Polyimide, Poybenzimidazole, Cellulose, Kevlar.
The porous carbon nanofiber of claim 1, wherein the high molecular weight pitch polymer of any one of claims 1 to 3 is formed by dissolving alone or blended with PAN to dissolve the spinning solution.
The method of claim 4, wherein
In the case of porous carbon nanofibers formed by electrospinning the spinning solution in which the high molecular weight pitch polymer and PAN are dissolved, pores having a diameter in the range of 0.5 to 1.4 nm are formed, and the 0.5 nm pores are 80% or more of the total pores. Porous carbon nanofibers, characterized in that the pores of 1.2nm is less than 20%.
A porous carbon material comprising the porous carbon nanofiber of claim 5.

The method according to claim 6,
The porous carbon material is a porous carbon material, characterized in that used in any one or more of the electric double layer capacitor electrode, fuel cell electrode, fuel cell diffusion layer, hydrophilic selection filter.

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