KR102008508B1 - Carbon nanotube-polymer composites and manufacturing method thereof - Google Patents

Abstract

The present invention relates to a carbon nanotube-polymer composite. More particularly, the present invention, as a carbon nanotube-polymer composite, including any one carbon material selected from graphene oxide and graphene quantum dots, carbon nanotubes bonded through π-π stacking interaction, and a polymer matrix, relates to a carbon nanotube-polymer composite, which not only uniformly disperses carbon nanotubes in the polymer matrix, but also improves electrical and physical properties compared to conventional carbon nanotube-polymer composites; and a manufacturing method thereof.

Description

Carbon Nanotube-Polymer Composite and Method for Manufacturing the Same {CARBON NANOTUBE-POLYMER COMPOSITES AND MANUFACTURING METHOD THEREOF}

The present invention relates to a carbon nanotube-polymer composite, and more particularly, to a carbon nanotube-polymer composite having improved electrical and physical properties using graphene oxide and graphene quantum dots, and a method of manufacturing the same.

The carbon nanotube-polymer composite can have a large contact force with the polymer due to the large surface area of the carbon nanotube (hereinafter referred to as 'CNT'), and thus can exhibit high strength and light weight, and high electrical conductivity of CNT. May have conductivity. Due to the light weight and high strength, the CNT-polymer composite may be applied to sporting goods, automobiles, military equipment, aircraft, etc., and may be used in various energy technology fields due to the conductive properties. In particular, due to its light weight, high strength and conductive properties, carbon nanotube-polymer composites are light and stable even in harsh environmental conditions. It can be applied to energy storage devices, transparent electrodes, electrostatic discharge materials, electromagnetic shielding materials and the like in the field of equipment.

CNTs must be evenly dispersed in a matrix such as a solvent or a polymer for use in the manufacture of various technical materials as described above. However, there is a strong tendency to aggregate into bundles in the matrix by attractive forces such as strong Van der Waals forces between CNTs. When the carbon nanotubes are agglomerated in the matrix, the carbon nanotubes may not exhibit the inherent properties of the carbon nanotubes or may have a problem in that the uniformity of the properties may be degraded when the thin films are manufactured.

In order to solve this problem, methods for uniformly dispersing CNTs in a matrix using chemical surface treatment of CNTs or organic dispersants have been proposed, but such methods are known to degrade the inherent electrical and physical properties of CNTs.

Therefore, the development of a new method that can be uniformly dispersed in the polymer without deteriorating the electrical and physical properties of the CNT is required.

Korea Patent Registration No. 10-1337867

Accordingly, an object of the present invention in consideration of the same as that of an additive is graphene oxide (Graphene Oxide, hereinafter, 'GO') so that carbon nanotubes are uniformly dispersed in a polymer in a carbon nanotube-polymer composite including carbon nanotubes and a polymer. And a graphene quantum dot (hereinafter referred to as 'GQD') as a dispersant to provide a carbon nanotube-polymer composite having improved electrical and physical properties, and a method of manufacturing the same.

In order to achieve the above object, the carbon nanotube-polymer composite is any one carbon material selected from graphene oxide (GO) and graphene quantum dots (GQD), π-π stacking interaction (π-π stacking interaction) It characterized in that it comprises a carbon nanotube and a polymer matrix coupled to any one of the carbon material through.

The weight ratio of the selected carbon material and the carbon nanotubes is combined in one of the weight ratios from 0.02: 1 to 1: 1.

In the carbon material, graphene oxide may be used having a size of 170 nm to 2060 nm, and graphene quantum dots may use a size between 5 nm and 15 nm.

As the polymer matrix, polyvinylalcohol, poly (3,4-ethylenedioxythiophene) (poly (3,4-ethylenedioxythiophene), hereinafter also referred to as 'PEDOT') and poly (3,4-ethylenedioxyti) Poly (3,4-ethylenedioxythiophene): poly (styrenesulfonate), which is a material doped with poly (styrenesulfonate, hereinafter referred to as 'PSS') with dopant Any one selected from (PEDOT: PSS) can be used.

In addition, the carbon nanotube-polymer composite manufacturing method of the present invention for achieving the above object, (a) preparing any one carbon material selected from graphene oxide (GO) and graphene quantum dots (GQD). Preparing a carbon material, (b) preparing a carbon nanotube mixture by mixing any one of the prepared carbon materials and carbon nanotubes in a solvent, and (c) mixing the carbon nanotube mixture with a polymer matrix. -Preparing a polymer composite.

When the carbon material is graphene oxide in step (a), the carbon material is prepared by ultrasonic dispersion of the graphene oxide for 30 minutes to 2 hours.

In the step (b), graphene oxide (GO) and carbon nanotubes are mixed into a carbon nanotube mixture by mixing the carbon material graphene oxide (GO) or graphene quantum dots (GQD) with the carbon nanotubes on a solvent. GO-CNT or graphene quantum dots (GQD) and the carbon nanotubes are bonded to the step of preparing a GOD-CNT.

For example, the step (b) may mix the weight ratio of any one carbon material and the carbon nanotubes in any one of a weight ratio of 0.02: 1 to 1: 1.

In addition, water or an organic solvent may be used as the solvent, and the organic solvent may be methanol, methanol, ethanol, n-propanol, isopropanol, and n-butanol. -butanol) is preferably used a solvent consisting of any one or a combination thereof.

Since the polymer matrix used in the preparation of the carbon nanotube-polymer composite is the same as that described in the above-described carbon nanotube-polymer composite, duplicate description thereof will be omitted.

The carbon nanotube-polymer composite of the present invention uses any one carbon material selected from graphene oxide (GO) and graphene quantum dots (GQD) as a dispersant to reduce the attractive force between carbon nanotubes, thereby reducing carbon nanotubes on the polymer matrix. Evenly disperse the tube and use conventional dispersants or carbon materials to achieve high electrical efficiency through π-π conjugation of the graphene oxide (GO) and graphene quantum dots (GQD) itself. Compared to when not used, there is an effect of showing excellent electrical properties. In addition, the carbon nanotube-polymer composite of the present invention has an effect of improving not only electrical properties but also physical properties indicating durability.

1 is a flow chart of the carbon nanotube-polymer composite manufacturing method of the present invention.
Figure 2 is a schematic diagram showing the carbon nanotube-polymer composite manufacturing method of the present invention.
Figure 3 is a schematic diagram showing the appearance of carbon nanotubes before using the graphene quantum dots (GQD) and after using the graphene quantum dots (GQD) according to an embodiment of the present invention.
4 is a scanning electron microscope (Scanning Electron Microscope, SEM) observation picture of the appearance of carbon nanotubes before and after using the graphene quantum dots (GQD) according to an embodiment of the present invention.
5 is a graph showing the sheet resistance (Sheet Resistance) change of the carbon nanotube-polymer composite prepared according to the embodiment of the present invention.
6 is a graph showing a change in electrical conductivity of the carbon nanotube-polymer composite prepared according to the embodiment of the present invention.
Figure 7 is a result showing the physical properties of the carbon nanotube-polymer composite prepared according to an embodiment of the present invention.

It should be noted that the technical terms used in the present invention are merely used to describe specific examples, and are not intended to limit the present invention. In addition, the technical terms used in the present invention should be construed as meanings generally understood by those skilled in the art unless they are specifically defined in the present invention, and are overly inclusive. It should not be interpreted in the sense of or in the sense of being excessively reduced.

In addition, singular forms used in the present invention include plural forms unless the context clearly indicates otherwise. In this specification, terms such as “consisting of” or “comprising” should not be construed as necessarily including all of the various components or steps described in the specification, and some of the components or some steps It should be construed that it may not be included or may further include additional components or steps.

The term "graphene oxides" represented as carbon materials throughout the present specification may include a structure in which a functional group containing oxygen (O), such as a carboxyl group, a hydroxy group, or an epoxy group, is bonded to graphene acid, but is not limited thereto. . In the present invention, graphene oxide has a size of 170 nm to 2060 nm.

Another carbon material, "Graphene Quantum Dot," refers to nano-sized fragments of graphene oxides or reduced graphene oxides.

DETAILED DESCRIPTION Hereinafter, the present invention will be described in detail with reference to the accompanying drawings, and this description is an example and can be implemented in various different forms by those skilled in the art. Do not.

1 and 2 is a view showing a method for producing a carbon nanotube-polymer composite of the present invention.

As shown in FIG. 1, the carbon nanotube-polymer composite of the present invention is prepared by preparing a carbon material (S100), preparing a carbon nanotube mixture (S200), and preparing a carbon nanotube-polymer composite (S300). .

The carbon material preparation step (S100) is a step of adjusting the particle size of the carbon material so that the graphene oxide (GO) or graphene quantum dots (GQD) as a carbon material is properly bonded to the surface of the carbon nanotube.

When graphene oxide (GO) is used as the carbon material in the carbon material preparation step (S100), the graphene oxide (GO) is ultrasonically dispersed for 30 minutes to 2 hours in an aqueous solution in an aqueous solution. As shown in FIG. 2, graphene oxide (GO) having various sizes is prepared according to ultrasonic dispersion time, and deionized water may be used as the aqueous solution.

The ultrasonic dispersion time is not necessarily limited to the above-mentioned ultrasonic dispersion time, but if the ultrasonic dispersion time is less than 30 minutes, the ultrasonic dispersion may not be properly performed, and thus the particle size of the carbon material (GO), which is a carbon material, may be large and may be combined with the carbon nanotubes at a required weight ratio. There is a problem that the dispersion rate of carbon nanotubes in the polymer matrix is low, and on the contrary, since the particle size of graphene oxide is hardly changed at an ultrasonic dispersion time of 2 hours or more, it is preferable to satisfy the above-mentioned range.

In the carbon material preparation step (S100), when graphene quantum dots (GQD) are used as the carbon material, graphene having a fine size of about 5 nm to 15 nm is prepared from a graphite raw material. Here, the graphene quantum dots are prepared by a graphene quantum dot manufacturing method such as chemical peeling method generally known in the art. Since the prepared graphene quantum dots have a size of 5 nm to 15 nm, unlike the graphene oxide (GO) described above, no separate ultrasonic dispersion process is performed.

The carbon nanotube mixture manufacturing step (S200) is a carbon material, the graphene oxide (GO) or graphene quantum dots (GQD) of the carbon material is ultrasonic dispersion is completed through the carbon material preparation step (S100) is mixed together on a carbon nanotube and a solvent When the carbon material is bonded to the surface of the carbon nanotubes through the π-π stacking interaction between the carbon material and the carbon nanotubes, the graphene oxide (GO) and the carbon nanotube ( A graphene oxide-carbon nanotube mixture (GO-CNT) or graphene quantum dot (GQD) bonded to CNTs) and a graphene quantum dot-carbon nanotube mixture (GOD-CNT) bonded to the carbon nanotubes (CNT) are prepared. .

Graphene oxide (GO) or graphene quantum dots (GQD) of the carbon material and the carbon nanotubes are mixed in a weight ratio of 0.02: 1 to 1: 1 to prepare a carbon nanotube mixture.

The carbon nanotube may be any one of single-walled carbon nanotubes (SWCNTs), double-walled carbon nanotubes (DWCNTs), and multi-walled carbon nanotubes (MWCNTs). Those containing two or more may be used, and may be appropriately selected according to the use of the carbon nanotube-polymer composite to be prepared.

The carbon nanotube mixture prepared through the carbon nanotube mixture manufacturing step (S200) is characterized in that carbon nanotubes fall apart separately due to the carbon material bonded to the surface of the carbon nanotubes by the attraction between the carbon nanotubes, and Since fin (GO) has a hydrophilic functional group such as a carboxyl group, a hydroxyl group or an epoxy group on the surface, the carbon nanotube mixture is water or methanol, ethanol, n-propanol or isopropanol. ) And alcohol solvents such as n-butanol.

3 and 4 illustrate the appearance of carbon nanotubes before using graphene quantum dots (GQD) and after using graphene quantum dots (GQD) according to an embodiment of the present invention.

3 and 4, single-walled carbon nanotube bundles (SWCNT bundles), which are bundles of carbon nanotubes aligned in a predetermined direction, do not exhibit aggregation of carbon nanotube units having a predetermined diameter. When only 10,000 graphene quantum dots (GQD) are added, it is confirmed that the attraction of carbon nanotubes is reduced and the carbon nanotube bundles are released and fall apart.

The carbon nanotube-polymer composite manufacturing step (S300) is a step of preparing a carbon nanotube-polymer composite by mixing the carbon nanotube mixture prepared through the carbon nanotube mixture manufacturing step (S200) with a polymer matrix.

The polymer matrix may be polyvinyl alcohol (polyvinylalcohol, PVA), poly (3,4-ethylenedioxythiophene) (PEDOT) and poly (3,4-ethylenedioxythiophene) (PEDOT) as a dopant poly (styrenesulfo). It is preferable to use any one selected from poly (3,4-ethylenedioxythiophene): poly (styrenesulfonate) (PEDOT: PSS) which is a material doped with Nate) (PSS). The present invention is not limited to the above-described specific polymer matrix, and any polymer matrix known in the art to which the present invention pertains may be used without limitation.

The prepared carbon nanotube-polymer composite may be manufactured in the form of a thin thin film, and the carbon nanotube-polymer composite of the present invention may be manufactured and used in various shapes and sizes depending on the use of the film.

Hereinafter, the carbon nanotube-polymer composite of the present invention will be described in more detail with reference to Examples.

Example 1 ultrasonically disperses graphene oxide (GO) for 10 minutes to make the particle size of the graphene oxide to 1070 nm, and the ultrasonic dispersion-completed graphene oxide multi-walled carbon nanotube (MWCNT) ) To prepare a carbon nanotube mixture, and to prepare a carbon nanotube-polymer composite by mixing the prepared carbon nanotube mixture with polyvinyl alcohol (polyvinylalcohol, PVA), the carbon nanotube polymer prepared in Example 1 The complex is abbreviated as "GO1-MWCNT".

Example 2 prepared a carbon nanotube-polymer composite in the same manner as in Example 1, except that the graphene oxide was ultrasonically dispersed for 2 hours to make the particle size of the graphene oxide 550 nm. Carbon nanotube polymer composite prepared by 2 is abbreviated as "GO2-MWCNT".

Example 3 prepared a carbon nanotube-polymer composite in the same manner as in Example 1, except that the graphene oxide was ultrasonically dispersed for 3 hours to make the particle size of the graphene oxide 370 nm. Carbon nanotube polymer composite prepared in 3 is abbreviated as "GO3-MWCNT".

Example 4 prepared a carbon nanotube-polymer composite in the same manner as in Example 1, except that the graphene oxide was ultrasonically dispersed for 2 hours to prepare 170 nm of the particle size of graphene oxide. The carbon nanotube polymer composite prepared in Example 4 is abbreviated as "GO4-MWCNT".

Example 5 prepared a carbon nanotube mixture by mixing graphene quantum dots (GQD) with a single-walled carbon nanotube as a carbon material, and the prepared carbon nanotube mixture was poly (3,4- Ethylenedioxythiophene): poly (styrenesulfonate) (PEDOT: PSS) was mixed to prepare a carbon nanotube-polymer composite.

Comparative Example 1 prepared a carbon nanotube-polymer composite in the same manner as in Example 1, except that graphene oxide having a particle size of 2060 nm was used without ultrasonic dispersion with graphene oxide, and prepared as Comparative Example 1. The carbon nanotube polymer composite is abbreviated as "GO0-MWCNT".

In Comparative Example 2, carbon was obtained by mixing ordinary single-walled carbon nanotubes with poly (3,4-ethylenedioxythiophene): poly (styrenesulfonate) (PEDOT: PSS) without using a dispersant. Nanotube-polymer composites are prepared.

Comparative Example 3 is the same method as Example 5, except that polyvinyl pyrrolidone (PVP) was used as a dispersant of conventional carbon nanotube-polymer composites instead of graphene oxide or graphene quantum dots (GQD). To prepare a carbon nanotube-polymer composite.

In order to confirm the electrical change of the carbon nanotube-polymer composite prepared according to the embodiment of the present invention, the sheet resistance and the change in electrical conductivity were measured, and the results are shown in FIGS. 5 and 6.

Figure 5 is a graph showing the change in sheet resistance (Sheet Resistance) according to the weight ratio of graphene oxide and carbon nanotubes in the carbon nanotube-polymer composite prepared according to the embodiment of the present invention.

As shown in FIG. 5, the smaller the particle size of the graphene oxide (GO) used, the more uniformly dispersed the carbon nanotubes even though the content of graphene oxide (GO) is reduced, the resistance of 10 ¹¹ Ω / square (sq) to 10 ⁵ Ω / square (sq) reduced by a million times.

6 is a graph showing a change in electrical conductivity of the carbon nanotube-polymer composite prepared according to the embodiment of the present invention.

As shown in Figure 6, the carbon nanotube-polymer composite of Comparative Example 3 using a well-known polyvinyl pyrrolidone (PVP) as a dispersant is a polyvinyl pyrrolidone (PVP) is a non-conductor surrounding the surface of the carbon nanotubes The electrical conductivity values on the order of 50 S / cm are shown. On the other hand, the carbon nanotube-polymer composite of Example 5 using graphene quantum dots (GQD) as a dispersant prevents carbon nanotubes from interfering with the π-π stacking interaction between carbon nanotubes and also on the surface of carbon nanotubes. Graphene quantum dot (GQD) itself, which is a bonded carbon material, has a π-π conjugation, so it is about three times or more compared to Comparative Example 3 using a conventional polyvinyl pyrrolidone (PVP) as a dispersant. It was confirmed to exhibit electrical conductivity.

It uses carbon oxide (GO) or graphene quantum dots (GQD) as the dispersant to reduce the attractive force between the carbon nanotubes to evenly disperse the carbon nanotubes on the polymer matrix, graphene oxide (GO) and Graphene quantum dots (GQD) itself exhibits excellent conductivity due to π-π conjugation (π-π conjugation) itself.

In order to confirm the physical property change of the carbon nanotube-polymer composite prepared according to the embodiment of the present invention, the Young's Modulus change of the carbon nanotube-polymer composite was measured. Here the Young's modulus represents the degree of durability when a change is caused by an external force.

Figure 7 is a result showing the physical properties of the carbon nanotube-polymer composite prepared according to an embodiment of the present invention.

As shown in FIG. 7A, when the carbon nanotube mixtures prepared in Examples 2, 4 and Comparative Example 1 are powdered into polyvinyl alcohol (PVA), which is a polymer matrix, the carbon nanotube-polymer composite Young's modulus increased rapidly, and the graphene oxide and carbon nanotubes showed an almost three-fold improvement in Young's modulus at a weight ratio of 1: 1.

And (b) of Figure 7 is a result showing the change in Young's Modulus (MWCNT) volume vs. multi-walled carbon nanotubes (MWCNT) in the carbon nanotube-polymer composite. As shown, the Young's Modulus was remarkably improved as the content of the carbon nanotube mixture was increased in the carbon nanotube-polymer composites prepared in Examples 2, 4 and Comparative Example 1.

Therefore, as described above, the carbon nanotube-polymer composite according to the present embodiment uses graphene oxide (GO) and graphene quantum dots (GQD) as dispersants, thereby maintaining carbon nanotubes inherent electrical properties. It can be seen that it causes the effect of increasing the dispersion degree of, and can also improve the physical properties of the carbon nanotube-polymer composite.

Claims (11)

Any one carbon material selected from graphene oxide having a size of 170 nm to 1070 nm and graphene quantum dots having a size of 5 nm to 15 nm;
carbon nanotubes bonded to any one selected carbon material through a π-π stacking interaction; And
A polymer matrix;
The carbon nanotube-polymer composite, characterized in that the weight ratio of any one selected carbon material and carbon nanotubes is any one from 0.02: 1 to 1: 1 by weight. delete delete delete The method of claim 1,
The polymer matrix is any one selected from polyvinyl alcohol, poly (3,4-ethylenedioxythiophene), and poly (3,4-ethylenedioxythiophene): poly (styrenesulfonate). Tube-polymer complex. (a) preparing a carbon material selected from graphene oxide having a size of 170 nm to 1070 nm and graphene quantum dots having a size of 5 nm to 15 nm;
(b) adding one of the prepared carbon materials and carbon nanotubes into a solvent and mixing the mixture with the graphene oxide-carbon nanotube mixture or the graphene oxide of the graphene oxide and the carbon nanotubes as a carbon nanotube mixture; Preparing a graphene quantum dot-carbon nanotube mixture in which a fin quantum dot and a carbon nanotube are combined; And
(c) mixing the carbon nanotube mixture with a polymer matrix to prepare a carbon nanotube-polymer composite;
In step (b),
The carbon nanotube-polymer composite manufacturing method, characterized in that for mixing the carbon material and the carbon nanotubes in any one of a weight ratio of 0.02: 1 to 1: 1. delete delete delete The method of claim 6,
The solvent,
Method for producing a carbon nanotube-polymer composite, characterized in that any one or more selected from water, methanol, ethanol, n-propanol, isopropanol, and n-butanol. The method of claim 6,
The polymer matrix is any one selected from polyvinyl alcohol, poly (3,4-ethylenedioxythiophene), and poly (3,4-ethylenedioxythiophene): poly (styrenesulfonate). Method for preparing tube-polymer composite.

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