KR102179310B1 - Aromatic polyimide modified carbon nanotube and mehtod for preparing the same - Google Patents

Abstract

According to an embodiment of the present invention, there is provided a modified carbon nanotube comprising an aromatic polyimide in which an aromatic amine and an aromatic acid anhydride are polymerized.

Description

Aromatic polyimide-modified carbon nanotube and its manufacturing method {AROMATIC POLYIMIDE MODIFIED CARBON NANOTUBE AND MEHTOD FOR PREPARING THE SAME}

The present invention relates to an aromatic polyimide-modified carbon nanotube and a method for producing the same.

Carbon nanotubes have a geometric feature of a diameter of several to tens of nanometers and a high aspect ratio, and are composed of only sp ² bonds between carbon atoms, and are used in various fields as a material exhibiting excellent mechanical strength, electrical conductivity, and thermal conductivity.

The application fields of carbon nanotubes can be largely divided into strength/lightweight field, electric conductivity/thermal conductivity application field, and environment/energy field. Among these, the application fields of electric conductivity/thermal conductivity include semiconductor trays, conductive paints, transparent electrodes, electronic circuits, heat dissipation parts, planar heating elements, tape reels, electromagnetic shielding materials, and tires.

On the other hand, aromatic polyimide (PI), which has a polymer form between an aromatic imine and an aromatic acid anhydride, has excellent electrical conductivity, mechanical properties, high thermal stability, excellent chemical resistance, and radiation resistance. Used in high-performance composites.

Polyimide has a property of being insoluble and insoluble in a number of organic solvents by forming a charge transfer complex through interaction between molecules. Accordingly, polyimide can be prepared through a two-step synthesis, specifically, by synthesizing a precursor polyamic acid (PAA), and then chemically or thermally imidizing the polyamic acid to prepare a polyimide. I can.

Recently, research has been conducted to improve the electrical conductivity by modifying the surface of the carbon nanotube, and for example, a method of improving the electrical conductivity of the carbon nanotube by introducing a functional group exhibiting conductivity has been known.

Based on this research direction, the present inventors have developed carbon nanotubes with significantly improved electrical conductivity compared to existing carbon nanotubes by modifying the surface of carbon nanotubes with compounds having imide functional groups.

The present invention is to solve the problems of the prior art described above, and an object of the present invention is to provide a modified carbon nanotube having excellent electrical conductivity and a method for manufacturing the same.

However, the problem to be solved by the present invention is not limited to the problems mentioned above, and other problems that are not mentioned will be clearly understood by those of ordinary skill in the art from the following description.

According to an embodiment of the present invention, there is provided a modified carbon nanotube comprising an aromatic polyimide in which an aromatic amine and an aromatic acid anhydride are polymerized.

According to one side, the aromatic amine may be 4,4'-oxyaniline (ODA; 4,4'-oxyaniline).

According to one side, the aromatic acid anhydride may be pyromellitic dianhydride (PMDA).

According to one side, the aromatic amine and the aromatic acid anhydride may be polymerized at a molar ratio of 1:1 to 1.05.

According to another embodiment of the present invention, (a) reforming the carbon nanotubes with an aromatic amine; (b) synthesizing a polyamic acid by polymerizing the aromatic amine and the aromatic acid anhydride; And (c) heating the polyamic acid to convert it into polyimide; containing, a method for producing a modified carbon nanotube is provided.

According to one side, the aromatic amine may be 4,4'-oxyaniline (ODA; 4,4'-oxyaniline).

According to one side, the aromatic acid anhydride may be pyromellitic dianhydride (PMDA).

According to one side, in the step (b), the aromatic amine and the aromatic acid anhydride may be polymerized at a molar ratio of 1:1 to 1.05.

The modified carbon nanotube of the present invention has an aromatic polyimide functional group, and thus can exhibit excellent electrical conductivity.

The effects of the present invention are not limited to the above effects, and should be understood to include all effects that can be deduced from the configuration of the invention described in the detailed description or claims of the present invention.

1 shows the structure of a modified carbon nanotube according to an embodiment of the present invention.
2 shows the results of measuring tensile strength of polyamic acid and polyimide according to an embodiment of the present invention.
3 shows a scanning electron microscope (SEM) image of polyamic acid and polyimide according to an embodiment of the present invention.
4 shows the results of FT-IR analysis of polyamic acid and polyimide according to an embodiment of the present invention.
5 shows DSC analysis results of polyamic acid and polyimide according to an embodiment of the present invention.

Hereinafter, exemplary embodiments will be described in detail with reference to the accompanying drawings. The same reference numerals in each drawing indicate the same members.

Various changes may be made to the embodiments described below. The embodiments described below are not intended to be limited to the embodiments, and should be understood to include all changes, equivalents, and substitutes thereto.

The terms used in the examples are used only to describe specific embodiments, and are not intended to limit the embodiments. Singular expressions include plural expressions unless the context clearly indicates otherwise. In the present specification, terms such as "comprise" or "have" are intended to designate the presence of features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, but one or more other features. It is to be understood that the presence or addition of elements or numbers, steps, actions, components, parts, or combinations thereof, does not preclude in advance the possibility.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which the embodiment belongs. Terms as defined in a commonly used dictionary should be interpreted as having a meaning consistent with the meaning in the context of the related technology, and should not be interpreted as an ideal or excessively formal meaning unless explicitly defined in this application. Does not.

In addition, in the description with reference to the accompanying drawings, the same reference numerals are assigned to the same components regardless of the reference numerals, and redundant descriptions thereof will be omitted. In describing the embodiments, when it is determined that a detailed description of related known technologies may unnecessarily obscure the subject matter of the embodiments, the detailed description thereof will be omitted.

Aromatic polyimide modified carbon nanotube

According to an embodiment of the present invention, there is provided a modified carbon nanotube comprising an aromatic polyimide in which an aromatic amine and an aromatic acid anhydride are polymerized. The carbon nanotubes themselves exhibit excellent electrical conductivity and can be applied as an excellent filler in fields requiring electrical conductivity such as semiconductor devices and electromagnetic wave shielding materials.

The aromatic polyimide that modifies the surface of the carbon nanotube may be in a form in which an aromatic amine and an aromatic acid anhydride are polymerized. Specifically, the aromatic amine is 4,4'-oxyaniline (ODA; 4,4'-oxyaniline). ), and the aromatic acid anhydride may be a pyromellitic dianhydride (PMDA), but is not limited thereto.

In addition, the aromatic amine and the aromatic acid anhydride may be polymerized at a molar ratio of 1:1 to 1.05. Based on the molar ratio of the aromatic amine 1, when the molar ratio of the aromatic acid anhydride is less than 1 or greater than 1.05, the viscosity of the monomer mixture for polymer formation may be excessively high or excessively low, and thus formation of the polymer itself may be difficult.

Method for producing aromatic polyimide-modified carbon nanotubes

According to another embodiment of the present invention, (a) reforming the carbon nanotubes with an aromatic amine; (b) synthesizing a polyamic acid by polymerizing the aromatic amine and the aromatic acid anhydride; And (c) heating the polyamic acid to convert it into polyimide; containing, a method for producing a modified carbon nanotube is provided.

Carbon nanotubes themselves exhibit excellent electrical conductivity, but have low dispersibility, so simply immersing the carbon nanotubes in a polyimide solution may not result in sufficient modification. Therefore, in the step (a), after modifying the carbon nanotubes with an aromatic amine, which is one monomer for polyimide polymerization, the polymerization reaction may be performed.

At this time, by immersing the carbon nanotubes in an acid solution, specifically a mixed solution of sulfuric acid and nitric acid, preferably a solution in which sulfuric acid and nitric acid are mixed in a volume ratio of 3: 1, the carbon nanotubes are placed on the surface. It can be modified to contain carboxy and hydroxy functional groups.

Then, by immersing the carbon nanotubes surface-modified with an acid solution in a solution containing an aromatic amine, specifically 4,4'-oxyaniline (ODA; 4,4'-oxyaniline), the carbon nanotubes surface-modified with an aromatic amine The tube can be synthesized. At this time, reaction efficiency can be improved by adding a dehydrating agent such as dimethylformamide (DMF), N,N'-dichlorohexylcarbodiimide (DCC) and a catalyst such as 4-dimethylaminopyridine (DMAP). It is not limited.

In step (b), a polymerization reaction between the aromatic acid anhydrides may be induced by adding an aromatic acid anhydride to the aromatic amine present on the surface of the carbon nanotube. Specifically, the aromatic acid anhydride may be a pyromellitic dianhydride (PMDA), but is not limited thereto. The material synthesized accordingly may be polyamic acid, and the product obtained after the step (b) is completed may be carbon nanotubes surface-modified with polyamic acid.

Meanwhile, in step (b), the aromatic amine and the aromatic acid anhydride may be polymerized at a molar ratio of 1:1 to 1.05. The viscosity of the polymer preparation solution according to the molar ratio limitation is the same as described above.

In the step (c), a cyclic imide may be synthesized by heating the polyamic acid, and the resulting final product may be a carbon nanotube surface-modified with an aromatic polyimide.

Hereinafter, the present invention will be described in more detail through examples. The following examples are described for the purpose of illustrating the present invention, and the scope of the present invention is not limited thereto.

Example 1: Synthesis of aromatic polyimide

16.442 g of 4,4'-oxyaniline (ODA) was dissolved in 230.497 g of a dimethylacetamide (DMAc) solvent. The obtained solution was added while controlling the molar ratio of pyromellitic dianhydride (PMDA), and then mechanically stirred for 4 hours.

The content of specific compounds is shown in Table 1 below, and the viscosity according to each molar ratio is measured and shown together.

PMDA: ODA
Molar ratio Viscosity (cP) PMDA content (g) ODA content (g) 100: 100 430,000 17.910 16.442 100.5: 100 330,000 18.000 16.442 101.3: 100 54,000 18.143 16.442

Thereafter, polyamic acid (PAA) was prepared from the solution through a dry-jet wet spinning process using a spinneret equipped with five holes having a diameter of 250 μm. At this time, the spinning process was performed while adjusting the draw ratios to 3, 6, and 9, respectively, and samples according to the draw ratios were named DR3, DR6, and DR9.

Next, polyimide (PI) was prepared by heating the prepared polyamic acid at an isothermal temperature of 100° C., 200° C., and 300° C. for 1 hour each, and heating up to 420° C. at a heating rate of 5° C./min. .

Tensile tests were performed on polyamic acid (PAA) and polyimide (PI) prepared using each of the samples (DR3, DR6, DR9), and the results are shown in Table 2 and FIG. 2 below.

Kinds Sample Elongation
(%) diameter
(㎛) tenacity
(J/g) The tensile strength
(MPa) Modulus
(GPa) PAA DR3 11.4±2.7 15.5±2.5 34.9±1.5 18.0±3.3 136.9±4.5 DR6 15.5±2.5 34.9±1.5 18.0±3.3 136.9±4.5 6.4±0.2 DR9 14.0±2.4 29.0±1.4 16.0±3.3 136.9±5.8 6.3±0.2 PI DR3 33.0±5.4 40.4±1.6 32.4±7.0 172.2±14.7 5.0±0.4 DR6 28.2±5.6 30.0±1.2 27.2±6.4 163.7±8.1 5.6±0.3 DR9 30.9±3.5 24.4±1.8 30.7±5.5 170.8±16.4 5.5±0.5

Example 2: Polyamic acid And measurement of physical properties of polyimide

Scanning electron microscope (SEM) images were observed for each of the polyamic acid and polyimide prepared according to Example 1, and FT-IR analysis was performed, and DSC analysis was additionally performed on the polyimide. Each result is shown in Figures 3 to 5.

As described above, although the embodiments have been described by the limited embodiments and drawings, various modifications and variations are possible from the above description by those of ordinary skill in the art. For example, even if the described techniques are performed in a different order from the described method, and/or the described components are combined or combined in a form different from the described method, or are replaced or substituted by other components or equivalents. Appropriate results can be achieved.

Therefore, other implementations, other embodiments, and equivalents to the claims also fall within the scope of the following claims.

Claims (8)

(a) reforming the carbon nanotubes with an aromatic amine;
(b) synthesizing a polyamic acid by polymerizing the aromatic amine and the aromatic acid anhydride; And
(c) heating the polyamic acid to convert it into polyimide; Including,
The aromatic amine is 4,4'-oxyaniline (ODA; 4,4'-oxyaniline),
The aromatic acid anhydride is pyromellitic dianhydride (PMDA),
In the step (a), 4-dimethylaminopyridine (DMAP) is further added as a dehydrating agent and catalyst comprising dimethylformamide (DMF), N,N'-dichlorohexylcarbodiimide (DCC) or both,
In the step (b), the aromatic amine and the aromatic acid anhydride are polymerized at a molar ratio of 1:1 to 1.05,
In the step (b), the polyamic acid is manufactured through a dry-jet wet spinning process, a method of manufacturing a modified carbon nanotube.
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