KR101837550B1 - Manufacturing method of nanocomposite fiber and nanocomposite fiber manufactured therefrom - Google Patents

Abstract

The present invention relates to a method for producing a composite nanofiber and a composite nanofiber produced thereby, and a method for manufacturing a composite nanofiber according to the present invention is an arc-discharge method using permalloy particles as a catalyst To produce a single-walled carbon nanotube-permalloy powder; And preparing a single-walled carbon nanotube-permalloy-poly (vinyl alcohol) composite nanofiber by wet spinning of a suspension designed for the single-walled carbon nanotube-permalloy powder and poly (vinyl alcohol) .

Description

Technical Field [0001] The present invention relates to a method for producing a composite nanofiber, and a composite nanofiber produced by the method. [0001] The present invention relates to a nanofiber composite nanofiber,

The present invention relates to a process for producing a composite nanofiber and a composite nanofiber produced thereby, and more particularly, to a process for producing a permalloy particle and a single-walled carbon nanotube composite by an arc-discharge method The present invention relates to a method for producing a composite nanofiber by wet spinning and a method for producing the composite nanofiber.

Carbon nanotubes (CNTs) have excellent properties such as excellent mechanical properties, electrical conductivity and thermal conductivity, which are superior to those of conventional carbon fibers. In addition, since carbon nanotubes have excellent electromagnetic wave shielding and absorption characteristics in the GHz band, researches on carbon nanotube-polymer composite materials have been actively conducted recently.

However, the carbon nanotubes are not uniformly dispersed in the polymer matrix, resulting in a problem that the electromagnetic wave shielding and absorption characteristics are reduced.

In order to solve this problem, researches have been conducted on carbon nanotubes containing transition metals such as iron, cobalt and nickel as catalysts. This is because strength and ductility of nanofibers increase with increasing content of magnetic nanoparticles in fibers There was a problem that it greatly decreased.

In addition, the dispersion of carbon nanotubes in various types of polymer bases and the absorption characteristics of carbon nanotubes have been studied. In addition, studies have been made to improve electromagnetic shielding properties by increasing the electrical conductivity through heat treatment of carbon nanotubes.

However, the above-mentioned conventional methods are still limited to improve the strength characteristics of the nanofibers and the electromagnetic wave absorption and shielding properties.

Korean Patent Registration No. 10-1375590 Korean Patent Laid-Open Publication No. 2014-0059843

Disclosed is a method for producing a composite nanofiber using an arc discharge method and a wet spinning method so as to have high strength and versatility, and to provide a composite nanofiber produced thereby.

The present invention, in order to solve the above problems,

Preparing a single-walled carbon nanotube-permalloy powder composite;

Dispersing the single walled carbon nanotube-permalloy powder composite in a surfactant solution to prepare a suspension of single walled carbon nanotube-permalloy powder composite;

Dissolving poly (vinyl alcohol) particles in the single-walled carbon nanotube-permalloy powder composite suspension to prepare a single-walled carbon nanotube-permalloy-poly (vinyl alcohol) suspension; And

(Vinyl alcohol) composite nanofibers comprising a single-walled carbon nanotube-permalloy-poly (vinyl alcohol) suspension comprising the steps of: preparing a composite nanofiber by wet spinning using a suspension of the single-walled carbon nanotube- And a manufacturing method thereof.

In the method for producing a single-walled carbon nanotube-permalloy-poly (vinyl alcohol) composite nanofiber according to the present invention, the step of preparing the single-walled carbon nanotube-permalloy powder composite includes: And applying an arc discharge method using graphite in which permalloy particles are embedded as a second electrode.

The arc discharge method used for manufacturing the single-walled carbon nanotube-permalloy powder composite according to the present invention can be freely selected by those skilled in the art and includes a power source for supplying a potential difference to the first electrode and the second electrode, And a plasma discharge is induced by a potential difference between one electrode and the second electrode.

In the method for producing single-walled carbon nanotube-permalloy-poly (vinyl alcohol) composite nanofibers according to the present invention, the arc discharge method is performed by applying a voltage of 35 to 40 V under a vacuum of 80 to 120 Torr .

In the method for producing a single walled carbon nanotube-permalloy-poly (vinyl alcohol) composite nanofiber according to the present invention, the step of preparing the single walled carbon nanotube-permalloy powder composite comprises: A first heat treatment to remove amorphous carbon from the permalloy powder composite, and a second heat treatment to perform a reduction process; And further comprising:

In the method for producing the single-walled carbon nanotube-permalloy-poly (vinyl alcohol) composite nanofiber according to the present invention, the first heat treatment step may be performed at a temperature of 350 to 450 ° C in air for 1 to 3 hours to remove the amorphous carbon. And the second heat treatment step is performed by heat treatment at 700 to 750 ° C in a hydrogen atmosphere for 1 to 3 hours so that the reduction process is performed.

In the method for producing the single-walled carbon nanotube-permalloy-poly (vinyl alcohol) composite nanofibers according to the present invention, the single-walled carbon nanotube-permalloy powder composite is dispersed in a surfactant solution, Wherein the weight ratio of the surfactant to the single-walled carbon nanotube-permalloy powder is 1: 3 to 1: 5 in the step of preparing the suspension of permalloy powder.

In the method for producing a single-walled carbon nanotube-permalloy-poly (vinyl alcohol) composite nanofiber according to the present invention, the surfactant is selected from the group consisting of sodium dodecyl sulfate, sodium octyle benzene sulfonate It is preferable to use one of sodium dodecyl benzene sulfate, ammonia lauryl sulfate (ALS) and alkyl sulfate (AS). More specifically, it is preferable to use sodium dodecyl sulfate.

In the method for producing a single-walled carbon nanotube-permalloy-poly (vinyl alcohol) composite nanofiber according to the present invention, the single-walled carbon nanotube-permalloy powder composite is dispersed in a surfactant solution to form a single-walled carbon nanotube- Powder composite suspension according to the present invention is characterized in that ultrasonic waves are applied.

In the method for producing the single-walled carbon nanotube-permalloy-poly (vinyl alcohol) composite nanofiber according to the present invention, the single-walled carbon nanotube-permalloy-poly (vinyl alcohol) The weight ratio of the single-walled carbon nanotube-permalloy powder to the poly (vinyl alcohol) is mixed in the range of 1: 0.5 to 1: 2.

In the method for producing the single-walled carbon nanotube-permalloy-poly (vinyl alcohol) composite nanofiber according to the present invention, the single-walled carbon nanotube-permalloy-poly (vinyl alcohol) And in the step of fabricating the fiber, passing the coagulation solution to remove the surfactant. Wherein the solidifying solution is characterized by removing the surfactant while solidifying the single-walled carbon nanotube-permalloy-poly (vinyl alcohol).

In the method for producing a single-walled carbon nanotube-permalloy-poly (vinyl alcohol) composite nanofiber according to the present invention, the solidifying solution is acetone.

The present invention also provides a single walled carbon nanotube-permalloy-poly (vinyl alcohol) composite nanofiber in which a single walled carbon nanotube-permalloy powder composite is dispersed in the poly (vinyl alcohol) produced by the production method of the present invention do.

The single-walled carbon nanotube-permalloy-poly (vinyl alcohol) composite nanofiber according to the present invention is characterized in that the single-walled carbon nanotube-permalloy powder composite forms a network within the poly (vinyl alcohol).

The single-walled carbon nanotube-permalloy-poly (vinyl alcohol) composite nanofiber according to the present invention is characterized in that the single-walled carbon nanotube is in an amount of 10 to 10 parts by weight per 100 parts by weight of the single- walled carbon nanotube- permalloy- By weight or more. The single-walled carbon nanotube-permalloy-poly (vinyl alcohol) composite nanofiber according to the present invention exhibits improved tensile strength characteristics and electric conductivity as the content of the single-walled carbon nanotubes increases and the single walled carbon nanotubes have a uniform distribution.

In the single-walled carbon nanotube-permalloy-poly (vinyl alcohol) composite nanofiber according to the present invention, the permalloy powder per 100 weight parts of the single-walled carbon nanotube-permalloy-poly (vinyl alcohol) Or more. The single-walled carbon nanotube-permalloy-poly (vinyl alcohol) composite nanofiber according to the present invention can contain not less than 30 parts by weight of permalloy powder having a high permeability, thereby improving the microwave shielding efficiency, And exhibits an effect of improving the EM energy absorption and reflection ability.

According to the method for producing a composite nanofiber of the present invention, uniform dispersion of permalloy and single-walled carbon nanotubes is achieved by an arc discharge process using permalloy particles as a catalyst, and the mixed weight of permalloy and single-walled carbon nanotubes SWNT / PNP / PVA composite nanofiber having high functionality and high electrical conductivity and high magnetic properties at the same time can be manufactured by wet spinning of the suspension prepared by controlling the viscosity of the suspension.

1 is a flowchart illustrating a method of fabricating a composite nanofiber according to an embodiment of the present invention.
2 is a schematic view showing an arc discharge method for manufacturing the single walled carbon nanotube-permalloy powder composite according to the present invention.
3 is a schematic view showing a wet spinning process for manufacturing a SWNT / PNP / PVA composite nanofiber according to the present invention.
4 is a TEM photograph of each SWNT / PNP powder according to Example 1 of the present invention,
(a) and (a1) are low-magnification TEM and HRTEM photographs of the as-prepared powder, respectively,
(b) and (b1) are TEM and HRTEM images of low-magnification TEM images of powders heat-treated at 400 ° C,
(c) and (c1) are respectively a low-magnification TEM and HRTEM photographs of the powder heat treated at 730 ° C.
5 is a TGA curve of the SWNT / PNP composite powder according to Example 1 of the present invention.
6 is a cross-sectional view and a side view of a SWNT / PNP / PVA composite nanofiber according to Example 1 of the present invention, wherein (a) is a sectional view and (b) is a side view.
7 is a typical stress-strain curve of the SWNT / PNP / PVA composite nanofiber according to Example 1 of the present invention.
8 is a typical magnetization hysteresis loop of a SWNT / PNP / PVA composite nanofiber according to Example 1 of the present invention.
9 is a graph showing tensile strength and saturation magnetization according to Example 1, Comparative Example 1, and conventional polymer conjugate fibers of the present invention.
10 shows a woven fabric using SWNT / PNP / PVA nanocomposite fibers prepared from Example 1 of the present invention.
11 is a graph showing scattering parameter results of SWNT / PNP / PVA fabrics prepared from Example 1 of the present invention, wherein (a) is a scattering parameter of dense fabric and (b) is scattering parameter of sparse fabric.
12 is a graph showing scattering parameter results of a SWNT / MNP / PVA fabric according to Comparative Example 2 of the present invention, wherein (a) is a scattering parameter of a dense fabric, (b) Scattering parameter.
13 is a graph showing power loss ratios of incident signals having different frequencies of the fabrics of Example 1 and Comparative Example 2 of the present invention.
14 is a schematic view of an apparatus for evaluating electrical conductivity and magnetic field response of a SWNT / PNP / PVA composite nanofiber according to Example 1 of the present invention,
(a) and (b) are respectively a plan view and a side view of the open circuit state,
(c) and (d) are respectively a plan view and a side view of the closed circuit state.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention and the manner of achieving them will become apparent with reference to the embodiments described in detail below with reference to the accompanying drawings. It is to be understood, however, that the same is by way of illustration and example only and is not to be construed in a limiting sense. The contents not described here are sufficiently technically inferior to those skilled in the art, and a description thereof will be omitted.

Hereinafter, a method for producing a composite nanofiber according to the present invention will be described in detail with reference to the accompanying drawings.

For convenience of explanation, single-walled carbon nanotubes are referred to as SWNT, permalloy particles as PNP, and poly (vinyl alcohol) (PVA) as PVA . In this specification, the SWNT / PNP powder (or mixture) is defined as a single-walled carbon nanotube-permalloy powder composite, and the SWNT / PNP / PVA composite nanofiber is defined as a composite nanofiber composed of SWNT, PNP particles and PVA, SWNT / PNP / PVA suspensions are defined as solutions containing SWNTs, PNP particles and PVA.

On the other hand, SWNT / PNP / PVA composite nanofibers are labeled SWNT-PNP-PVA composite nanofibers. SWNT / PNP / PVA suspension is SWNT-PNP-PVA suspension Can be indicated.

1 is a flowchart illustrating a method of fabricating a composite nanofiber according to an embodiment of the present invention.

Referring to FIG. 1, a method for fabricating a composite nanofiber according to an embodiment of the present invention includes the steps of synthesizing SWNT / PNP powder (S110), preparing a surfactant solution (S120), fabricating a SWNT / PNP suspension (S130) / PVA suspension manufacturing step (S140) and a SWNT / PNP / PVA composite nanofiber manufacturing step (S150).

In the SWNT / PNP powder synthesis step (S110), an SWNT / PNP mixture composed of SWNT and PNP particles is synthesized by an arc discharge method.

At this time, single-walled carbon nanotube-permalloy powder composite is synthesized by arc discharge method with permalloy particles embedded in graphite anode.

Specifically, the SWNT / PNP powder synthesis step (S110) includes an arc discharge SWNT / PNP powder production process, a primary heat treatment process, and a secondary heat treatment process.

FIG. 2 is a schematic view showing an arc discharge method for manufacturing a SWNT / PNP mixture according to the present invention.

Referring to FIG. 2, an arc discharge SWNT / PNP mixture manufacturing process applies a voltage 230 between an anode 210 and a cathode 220 under a vacuum. The arc discharge SWNT / PNP mixture 240 is collected by arc discharge between the two electrodes 210 and 220.

Of the two electrodes 210 and 220, the anode 210 is composed of graphite 212 and permalloy particles (PNP particles) 214 embedded in the graphite 212, and the cathode 220 is pure graphite .

In this example, PNP particles 214 were selected as catalysts for SWNTs to optimize the magnetic properties of the SWNT / PNP powder. This is because the PNP particles 214 are materials with high permeability.

In this embodiment, SWNT, which is part of the SWNT / PNP mixture composition, is one of the most promising nanofillers as a reinforcing material of composite nano materials because of its excellent mechanical properties.

Arc discharge is performed by applying a voltage of 35 to 40 V in a vacuum state of 80 to 120 Torr between a graphite anode 220 and a graphite anode 210 in which PNP particles 214 are embedded during arc discharge SWNT / .

At this time, if the pressure is less than 80 Torr or the voltage is less than 35 V, the arc discharge may be insufficient. Conversely, if the pressure exceeds 120 Torr or the voltage exceeds 40 V, the uniformity of the generated powder may be lowered.

Single wall carbon nanotube-permalloy powder composite consisting of PNP particles 244, SWNT 242 and amorphous carbon (not shown) uniformly dispersed by this arc discharge, SWNT / PNP nano powder 240, Can be obtained.

However, since the SWNT / PNP mixture 240 obtained by the arc discharge contains amorphous carbon which is poor in mechanical and chemical characteristics, it is necessary to further include the first and second heat treatment steps to remove the amorphous carbon desirable.

The first annealing process is a process for removing amorphous carbon contained in an arc discharge SWNT / PNP mixture, that is, an arc discharge SWNT / PNP powder.

The first heat treatment process may be performed by heat-treating the arc discharge SWNT / PNP powder at a temperature of 350 ° C to 450 ° C in the air for 1 to 3 hours, preferably at a temperature of 400 ° C in the air for 2 hours Can be performed. At this time, if the temperature of the first heat treatment process is less than 350 ° C or less than 1 hour, the removal of amorphous carbon may be insufficient. Conversely, if the temperature of the primary heat treatment process exceeds 450 DEG C or the time exceeds 3 hours, the process time may be prolonged without any further effect.

The second annealing process is a process for obtaining a final SWNT / PNP powder through a reduction process. That is, the secondary heat treatment process helps to reduce the PNP particles oxidized with PONP (permalloy oxide nanoparticles) during the first heat treatment process.

For this purpose, the second heat treatment process can be performed by heat-treating the arc discharge SWNT / PNP powder from which the amorphous carbon has been removed at a temperature of 700 ° C to 750 ° C in a hydrogen atmosphere for 1 to 3 hours, Lt; RTI ID = 0.0 > 730 C. < / RTI > At this time, if the temperature of the second heat treatment process is less than 700 ° C or less than 1 hour, the reduction may be insufficient and it may be difficult to obtain the desired SWNT / PNP powder. Conversely, if the temperature of the second heat treatment process exceeds 750 캜 or the time exceeds 3 hours, the process time may be prolonged without any further effect.

As a result, a SWNT / PNP mixture compounded with SWNT and PNP particles is synthesized by reduction treatment.

The single-walled carbon nanotube-permalloy powder composite synthesized by the SWNT / PNP powder synthesis step (S110) by the arc discharge having such a structure is composed of the uniformly dispersed SWNTs 242 and PNP particles 244.

In the step of preparing a surfactant solution (S120), a solution containing a surfactant is prepared by dissolving a surfactant in a solvent. The surfactant solution can be prepared by adding a certain amount of a surfactant to a certain amount of solvent and then ultrasonic treatment for several minutes to dissolve the surfactant solution.

Surfactants are used to obtain uniformly dispersed SWNT / PNP powders. For example, the surfactant may be selected from the group consisting of sodium dodecyl sulfate (SDS), sodium octyle benzene sulfonate, sodium dodecyl benzene sulfate (SDBS), ammonium lauryl sulfate Sulfates (ALS), alkyl sulfates (AS), and the like, and at least one of them may be selected. Preferably, the surfactant may use sodium dodecyl sulfate (SDS). As the solvent, distilled water may be used.

The SWNT / PNP suspension preparation step (S130) comprises dispersing a single-walled carbon nanotube-permalloy powder composite in the surfactant solution to prepare a single-walled carbon nanotube-permalloy composite suspension.

The single-walled carbon nanotube-permalloy powder composite suspension is preferably prepared by ultrasonication for several hours in order to improve the dispersibility of the single-walled carbon nanotube-permalloy powder composite.

From the viewpoint of improving dispersibility, it is preferable that the suspension of single-walled carbon nanotube-permalloy powder composite is optimized to a weight ratio of surfactant to single-walled carbon nanotube-permalloy powder composite of 1: 4.

The single-walled carbon nanotube-permalloy powder composite suspension preparation step (S140) comprises the steps of adding a predetermined amount of poly (vinyl alcohol) particles to the prepared single-walled carbon nanotube-permalloy powder composite suspension, heating and ultrasonicizing the dispersion for several tens of minutes, To prepare a suspension of carbon nanotube-permalloy-poly (vinyl alcohol).

Poly (vinyl alcohol) particles use PVA (molecular weight: 146,000 ~ 186,000; 99 +% hydrolyzed) particles with the desired weight.

SWNT / PNP powders in single-walled carbon nanotube-permalloy powder composite suspensions are used as nanofillers in PVA solutions containing surfactants.

This single walled carbon nanotube-permalloy-poly (vinyl alcohol) suspension is mixed such that the weight ratio of the single walled carbon nanotube-permalloy powder composite to the poly (vinyl alcohol) particles ranges from 1: 0.5 to 1: 2 .

This composition design increases the content of single-walled carbon nanotubes in single-walled carbon nanotubes-permalloy-poly (vinyl alcohol) composite nanofibers to improve the electrical conductivity and saturation magnetization (M _S ) Thereby contributing to improvement of characteristics and tensile strength characteristics.

The single-walled carbon nanotube-permalloy-poly (vinyl alcohol) suspension can be prepared by ultrasonication at a temperature of 50 to 150 ° C. for 10 minutes to 1 hour, preferably at a temperature of 95 ° C. And sonication for 30 minutes.

At this time, if the temperature is less than 50 ° C or the treatment time is less than 10 minutes, the effect of improving the dispersibility may be insufficient. Conversely, if the temperature exceeds 150 ° C or the treatment time exceeds 1 hour, Can only be long.

3 is a schematic view schematically illustrating a wet spinning process for producing a single-walled carbon nanotube-permalloy-poly (vinyl alcohol) composite nanofiber according to the present invention.

3, the single-walled carbon nanotube-permalloy-poly (vinyl alcohol) suspension nanofibers-permalloy-poly (vinyl alcohol) suspension 310 is prepared by injecting a single- (Vinyl alcohol) composite nanofibers (hereinafter referred to as " single-walled carbon nanotube-permalloy-poly (vinyl alcohol) composite nanofibers 350). Thus, high strength and multi-functional single-walled carbon nanotube-permalloy-poly (vinyl alcohol) composite nanofibers are produced by wet spinning from single-walled carbon nanotube-permalloy-poly (vinyl alcohol) suspensions.

At this time, acetone can be used for the coagulation solution 330, and the surfactant is removed by acetone in the process of manufacturing single-walled carbon nanotube-permalloy-poly (vinyl alcohol) composite nanofibers.

On the other hand, after the single-wall carbon nanotube-permalloy-poly (vinyl alcohol) composite nanofiber is collected, a drying process at room temperature in air may be further performed to obtain spiral composite nanofibers.

In the single-walled carbon nanotube-permalloy-poly (vinyl alcohol) composite nanofiber prepared by the method of the present invention, the weight of the single-walled carbon nanotube and the permalloy were as high as 12.0% and 38.0%, respectively.

Accordingly, the single-walled carbon nanotube-permalloy-poly (vinyl alcohol) composite nanofiber of the present invention had a tensile strength of up to 700 MPa and an electric conductivity of 96.7 Sm ^{- 1} due to the high SWNT content.

In addition, the SWNT / PNP / PVA composite nanofiber of the present invention exhibited a saturation magnetization (M _S ) of 24.8emug ^{- 1} at maximum because of the high weight of PNP particles.

Further, the EMI attenuation of the SWNT / PNP / PVA composite nanofibers woven from the SWNT / PNP / PVA composite nanofibers of the present invention approaches 100% when tested by electromagnetic waves having a frequency higher than 6 GHz.

The high-strength and multi-functional single-walled carbon nanotube-permalloy-poly (vinyl alcohol) composite nanofiber of the present embodiment, which is combined with functional properties such as electrical conductivity and magnetic properties, Devices, multifunctional fabrics for shielding electromagnetic waves, and the like.

Example

Hereinafter, the configuration and operation of the present invention will be described in more detail with reference to preferred embodiments of the present invention. It is to be understood, however, that the same is by way of illustration and example only and is not to be construed in a limiting sense.

The contents not described here are sufficiently technically inferior to those skilled in the art, and a description thereof will be omitted.

< Example 1> single wall  Carbon nanotubes - permalloy  Synthesis of Powder Composite

Single walled carbon nanotube - permalloy powder composite was prepared by arc discharge method.

First, a voltage of 35 to 40 V was applied between a graphite anode and a graphite anode having embedded permalloy particles under a vacuum of 80 to 120 Torr. At this time, a single walled carbon nanotube-permalloy powder composite was collected between the two electrodes by arc discharge.

Then, the collected arc discharge SWNT / PNP powder was heat-treated at 400 ° C in air for 2 hours in order to remove amorphous carbon from the produced single-walled carbon nanotube-permalloy powder composite. Then, a second heat treatment was performed at a temperature of 730 ° C. in a hydrogen atmosphere for 2 hours to perform a reduction process, thereby synthesizing a final SWNT / PNP powder.

< Experimental Example > Single wall  Carbon nanotubes - permalloy  Powder composite TEM  analysis

FIG. 4 is a TEM photograph of each single-walled carbon nanotube-permalloy powder composite according to Example 1 of the present invention. FIGS. 4A and 4B are TEM images of the low- and high- (B) and (b1) are TEM and HRTEM photographs of low-magnification TEM and HRTEM images of powders heat-treated at 400 ° C, and (c) and - Magnification TEM and HRTEM pictures.

4 (a) and (a1), the single-walled carbon nanotube-permalloy powder composite prepared in Example 1 was wrapped in spherical amorphous carbon (AC), and 20 nm diameter PNP particles were dispersed uniformly with SWNT .

Referring to FIGS. 4 (b) and 4 (b1), the single-walled carbon nanotube-permalloy powder composite prepared in Example 1 had amorphous carbon (AC) removed during heat treatment at 400 ° C. in air. The PNP particles changed to PONP (permalloy oxide nanoparticles) during this process.

Referring to FIGS. 4 (c) and 4 (c1), amorphous carbon (AC) was not observed in the nanopowder after heat treatment at 730 ° C. in a hydrogen atmosphere, and PNP particles were uniformly dispersed with SWNT. Also, it can be seen that the size of the PNP particles is increased from about 20 nm to 50 nm.

< Experimental Example > Single wall  Carbon nanotubes - permalloy  Powder composite TGA  analysis

SWNTs - TGA analysis of the composite powder permalloy 25 ~ 1000 ℃ temperature range, from the air atmosphere to 5 ℃ min ^-1 Respectively.

FIG. 5 is a TGA curve of the SWNT / PNP composite powder according to Example 1 of the present invention. The SWNT / PNP composite powder prepared before and after the heat treatment was A at a temperature of 400 ° C. and B at a temperature of 730 ° C., 2 Heat treatment was defined as C respectively.

Referring to FIG. 5, amorphous carbon is completely removed in the case of C heat-treated up to the second step. Also, the quantitative weight ratios of SWNT and PNP of Powder C heat-treated to the second stage were 24.0 and 76.0%, respectively.

Table 1 below shows the weight ratios of amorphous carbon (AC), single-walled carbon nanotubes, and permalloy after the first-stage heat treatment and the second-stage heat treatment.

AC (wt%) SWNTwt%) PNP (wt%) As produced 68.0 12.0 20.0 400 ° C in air 2hs 10.0 22.0 68.0 400 ° C in air 2hs & 730 ° C in H ₂ 1h 0.0 24.0 76.0

The single-walled carbon nanotube-permalloy powder composite produced by the present invention exhibits an effect of uniformly dispersing PNP particles having a high weight in the fibers due to arc discharge treatment.

< Example > Single wall  Carbon nanotubes - permalloy - Poly ( Vinyl alcohol Manufacture of Composite Nanofibers

The SDS solution was prepared by sonicating 2 g of SDS (Sigma-Aldrich) as a surfactant for 2 minutes and dissolving in 50 ml of distilled water.

0.5 g of the SWNT / PNP powder prepared in the above example was added to the SDS solution and dispersed by ultrasonic treatment for 1 hour to prepare a SWNT / PNP suspension. At this time, the weight ratio of the SDS particles to the SWNT / PNP powder was optimized to 1: 4.

Then 0.5 g of PVA (molecular weight: 146,000 to 186,000; 99 +% hydrolyzed) particles of PVA (Sigma-Aldrich) were added to the SWNT / PNP suspension and sonicated at 95 ° C for 30 minutes to give a SWNT / PNP / PVA suspension . At this time, the weight ratio of SWNT / PNP powder to the PVA particles of the SWNT / PNP suspension was mixed as shown in Table 2 below.

Suspension Distilled water (ml) SWMT / PNP
(g) SDS
(g) PVA
(g) SWNT / PNP
: PVA One 50 0.5 2 0.8 1: 1.6 2 50 0.5 2 0.5 1: 1 3 50 0.5 2 0.3 1: 0.6

The SWNT / PNP / PVA suspension was then extruded into a coagulating solution by a 160.0 micron diameter needle of the syringe using a wet spinner as shown in Figure 3, at the same time the continuous filaments were collected in failure and then air Lt; / RTI &gt; At this time, acetone was used as a coagulating solution, and SDS as a surfactant was removed by acetone.

Comparative Example  One

Conventional PVA / MNP (composite nanofiber) nanofibers were used.

Comparative Example  2

Fabrics woven with conventional SWNT / MNP / PVA composite nanofibers were prepared using commercially available SWNT powders as nanofillers. In general, when SWNT is purchased, SWNT and magnetic particles such as iron, nickel, and cobalt are contained therein.

< Experimental Example> Morphology  Measure

The morphology of the single-walled carbon nanotube-permalloy-poly (vinyl alcohol) composite nanofiber prepared in the example of the present invention was observed using a JSM-5800 scanning electron microscope.

6 is a cross-sectional view and a side view of a SWNT / PNP / PVA composite nanofiber according to Example 1 of the present invention, wherein (a) is a sectional view and (b) is a side view. As shown in FIG. 6 (b), the diameter of the SWNT / PNP / PVA composite nanofiber of Example 1 is about 18 μm, has a smooth and uniform surface. Referring to Figure 6 (a), the significant shrinkage of the fractured section of the SWNT / PNP / PVA composite nanofiber of Example 1 shows good firing characteristics.

< Experimental Example>  Tensile strength measurement

The fracture strength of the composite nanofibers prepared in the examples of the present invention was measured by a tensile test of single filaments. The stress-strain curves of the composite nanofibers were obtained from a TA Instrument Q800 Dynamic Mechanical Analyzer.

Fig. 7 is a graph showing the stress-strain (Fig. 7) of the single-walled carbon nanotube-permalloy-poly (vinyl alcohol) composite nanofiber prepared according to the embodiment of the present invention by the mixing ratio of single walled carbon nanotube- permalloy composite and polyvinyl alcohol stress-strain.

Referring to Figure 7, In Example 1, when the mixing ratio of the single-walled carbon nanotube-permalloy composite and the polyvinyl alcohol was 1: 0.6, the breaking strength of the SWNT / PNP / PVA composite nanofiber was 700 MPa at maximum and the single walled carbon nanotube- permalloy composite The higher the fracture strength is, the higher the ratio is.

< Experimental Example>  Magnetization measurement

The saturation magnetization was measured with a Quantum Design Versalab (VSM). The fibers were first chopped into small pieces and placed in plastic tubes. Next, the hysteresis loop was measured by the VSM and the saturation magnetization was calculated.

8 is a magnetization hysteresis loop of a SWNT / PNP / PVA composite nanofiber according to Example 1 of the present invention.

As shown in Fig. 8, the saturation magnetization (M _S ) of the SWNT / PNP / PVA composite nanofibers according to Example 1 reached 24.8 emug ^-1 . This is because the permalloy content (38.0% by weight) contained in the single-walled carbon nanotube-permalloy-poly (vinyl alcohol) composite nanofiber is high and the microwave shielding efficiency and EM energy absorption and reflection This is because the ability has greatly improved.

< Experimental Example >

9 is a graph comparing tensile strength and saturation magnetization according to Example 1, Comparative Example 1, and conventional polymer conjugate fibers of the present invention.

9, the fracture strength of the SWNT / PNP / PVA composite nanofiber of Example 1 of the present invention was at most 700 MPa and the saturation magnetization was 24.8 emug ^-1 , which was higher than that of the PVA / MNP fiber of Comparative Example 1 , The fracture strength of the SWNT / PNP / PVA composite nanofiber of Example 1 was improved about 9 times by the reinforcement of SWNTs.

In addition, the saturation magnetization (M _S ) of the SWNT / PNP / PVA composite nanofiber of Example 1 was about 4 to 6 times higher than that of the PVA / NMP fiber of Comparative Example 1. This can be attributed to the fact that Example 1 contained a high content (38.0% by weight) of PNP having excellent magnetic properties.

< Example > Fabrication of fabric structure

The SWNT / PNP / PVA composite nanofibers prepared in Example 1 were woven with a lab scale weaving machine to produce a dense fabric structure of 42 x 9 fiber bundle / cm ² and a coarse fabric structure of 8 x 9 fiber bundle / cm ² Respectively.

The manufactured fabric structure is shown in Fig.

< Experimental Example > Scattering parameters of fiber>

The scattering parameters of the composite nanofibers were measured by a vector network analyzer and the frequency range was set in the range of 0 to 10 GHz.

11 and 12 are graphs showing scattering parameter results of the fabric of Example 1 of the present invention and the fabric of Comparative Example 2, wherein (a) is a scattering parameter of dense fabric, (b) is scattering of coarse fabric Parameter.

< Experimental Example > EMI shielding performance of fabric structure

The EMI shielding effect (SE) of a composite nanofiber is an EM radiation reflection / absorption ability that can be expressed in terms of the ratio of the received power to the transmission power.

The EMI attenuation was calculated from the scattering parameter measured by the power loss (P _loss ) shielded by the composite nanofabric with the incident power (P ₀ ) of the electromagnetic wave by the microstrip line method.

13 is a graph showing the power loss ratios of incident signals having different frequencies of the fabric according to Example 1 and Comparative Example 2 of the present invention.

Referring to FIG. 13, it can be seen that the SWNT / PNP / PVA fabric fabricated in Example 1 has far better EMI shielding performance than the SWNT / MNP / PVA fabric of Comparative Example 2. The power loss of the SWNT / PNP / PVA fabric fabricated in Example 1 approaches 100% at frequencies exceeding 6 GHz.

< Experimental Example > Electrical conductivity of fiber and Magnetic field  Response>

14 is a schematic view of an apparatus for evaluating electrical conductivity and magnetic field response of a SWNT / PNP / PVA composite nanofiber according to Example 1 of the present invention. The magnetic field near the surface of the fiber spring is measured by Gauss / Tesla meter).

Figs. 14A and 14B are a plan view and a side view of the open circuit state, and Figs. 14C and 14D are respectively a plan view and a side view of the closed circuit state. Battery pack, LED lamp, copper plate, and SWNT / PNP / PVA fiber springs. Battery packs, LED lamps, copper plates and SWNT / PNP / PVA fiber springs were connected in series to show the circuit opening and closing. The open circuit state is an initial state, in which fiber and copper are connected and a magnetic field of 690 G is applied in the open circuit state. Two small magnets fixed with pivots were used to generate the magnetic field.

14 (a) and 14 (b), in the open circuit state, the fiber springs are not connected to the copper plate.

14 (c) and 14 (d), the fiber springs and the copper plate are brought into contact with each other by the deformation of the fiber springs under the magnetic field 690G to form the closed circuit.

This is because a relatively strong and weak magnetic field is generated in the vicinity of the fiber spring when the magnet is moved, and as a result, the fiber spring is deformed under the magnetic field.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, and that various changes, substitutions and alterations can be made therein without departing from the spirit and scope of the invention. However, it should be understood that such substitutions, changes, and the like fall within the scope of the following claims.

210: anode 212: graphite
214: Permalloy particles 220: cathode
230: voltage 240: arc discharge SWNT / PNP mixture
242: SWNT 244: PNP particles
310: SWNT / PNP / PVA suspension 320: syringe
325: Needle 330: Solidification solution
340: Failure 350: SWNT / PNP / PVA composite nanofiber

Claims (16)

Preparing a single-walled carbon nanotube-permalloy powder composite;
Dispersing the single walled carbon nanotube-permalloy powder composite in a surfactant solution to prepare a suspension of single walled carbon nanotube-permalloy powder composite;
Dissolving poly (vinyl alcohol) particles in the single-walled carbon nanotube-permalloy powder composite suspension to prepare a single-walled carbon nanotube-permalloy-poly (vinyl alcohol) suspension; And
Preparing a composite nanofiber by wet spinning using the single-walled carbon nanotube-permalloy-poly (vinyl alcohol) suspension; and
Wherein the step of preparing the single-walled carbon nanotube-permalloy powder composite comprises:
A first heat treatment so as to remove amorphous carbon, and
Performing a secondary heat treatment so as to perform a reduction process; Lt; RTI ID = 0.0 &gt;
(Method for manufacturing single walled carbon nanotube-permalloy-poly (vinyl alcohol) composite nanofiber.

The method according to claim 1,
Wherein the step of preparing the single-walled carbon nanotube-permalloy powder composite comprises:
And applying arc discharge method using a first electrode including graphite and graphite containing permalloy particles as a second electrode.
(Method for manufacturing single walled carbon nanotube-permalloy-poly (vinyl alcohol) composite nanofiber.
3. The method of claim 2,
The arc discharge method
Is carried out by applying a voltage of 35 to 40 V under a vacuum of 80 to 120 Torr
(Method for manufacturing single walled carbon nanotube-permalloy-poly (vinyl alcohol) composite nanofiber.
delete The method according to claim 1,
The primary heat treatment step
Followed by heat treatment at a temperature of 350 ° C to 450 ° C in air for 1 to 3 hours.
(Method for manufacturing single walled carbon nanotube-permalloy-poly (vinyl alcohol) composite nanofiber.
The method according to claim 1,
The second heat treatment step
Followed by heat treatment at a temperature of 700 ° C to 750 ° C in a hydrogen atmosphere for 1 to 3 hours.
(Method for manufacturing single walled carbon nanotube-permalloy-poly (vinyl alcohol) composite nanofiber.
The method according to claim 1,
In the step of dispersing the single-walled carbon nanotube-permalloy powder composite in a surfactant solution to prepare a suspension of single-walled carbon nanotube-permalloy powder composite
Wherein the weight ratio of the surfactant to the single-walled carbon nanotube-permalloy powder is 1: 3 to 1: 5
(Method for manufacturing single walled carbon nanotube-permalloy-poly (vinyl alcohol) composite nanofiber.
8. The method of claim 7,
The step of dispersing the single-walled carbon nanotube-permalloy powder composite into a surfactant solution to produce a suspension of single-walled carbon nanotube-permalloy powder composite comprises applying ultrasound
(Method for manufacturing single walled carbon nanotube-permalloy-poly (vinyl alcohol) composite nanofiber.
8. The method of claim 7,
The surfactant may be selected from the group consisting of sodium dodecyl sulfate, sodium octyle benzene sulfonate, sodium dodecyl benzene sulfate, ammonium lauryl sulfate (ALS) And alkyl sulfate (Alkyl Sulfate (AS)).
(Method for manufacturing single walled carbon nanotube-permalloy-poly (vinyl alcohol) composite nanofiber.
The method according to claim 1,
In the step of preparing composite nanofibers by wet spinning using the single-walled carbon nanotube-permalloy-poly (vinyl alcohol) suspension
And the weight ratio of the single-walled carbon nanotube-permalloy powder to the poly (vinyl alcohol) is in the range of 1: 0.5 to 1: 2
(Method for manufacturing single walled carbon nanotube-permalloy-poly (vinyl alcohol) composite nanofiber.
The method according to claim 1,
Wherein the step of preparing the composite nanofibers by wet spinning using the single-walled carbon nanotube-permalloy-poly (vinyl alcohol) suspension includes passing the coagulation solution to remove the surfactant
(Method for manufacturing single walled carbon nanotube-permalloy-poly (vinyl alcohol) composite nanofiber.
12. The method of claim 11,
The coagulation solution
Acetone
(Method for manufacturing single walled carbon nanotube-permalloy-poly (vinyl alcohol) composite nanofiber.
The composite nanofiber prepared by the manufacturing method of claim 1
A single-walled carbon nanotube-permalloy powder composite dispersed in poly (vinyl alcohol)
Single wall carbon nanotube - permalloy - poly (vinyl alcohol) composite nanofiber.
14. The method of claim 13,
Wherein the single-walled carbon nanotube-permalloy powder composite in the poly (vinyl alcohol) forms a mutual network
Single wall carbon nanotube - permalloy - poly (vinyl alcohol) composite nanofiber.
14. The method of claim 13,
Wherein the single-walled carbon nanotube is contained in an amount of 10 parts by weight or more per 100 parts by weight of the total of the single-walled carbon nanotube-permalloy-poly (vinyl alcohol)
Single wall carbon nanotube - permalloy - poly (vinyl alcohol) composite nanofiber.
14. The method of claim 13,
Wherein the permalloy powder is contained in an amount of 30 parts by weight or more per 100 parts by weight of the total of the single-walled carbon nanotube-permalloy-poly (vinyl alcohol) composite nano-
Single wall carbon nanotube - permalloy - poly (vinyl alcohol) composite nanofiber.

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