KR20150090628A - A Manufacturing Method of CNT-Alumina composite - Google Patents

Abstract

The present invention relates to a manufacturing method of a carbon nanotube-alumina (CNT-Alumina) composite and, more specifically, to a manufacturing method of a CNT-Alumina composite, which is capable of detecting a correlation of zeta potential with respect to a pH of a carbon nanotube dispersed solution and an alumina suspension, and manufacturing a CNT-Alumina composite having high fracture toughness using the same. According to an embodiment of the present invention, a manufacturing method of a CNT-Alumina composite comprises: a first step for manufacturing a carbon nanotube dispersed solution; a second step for regulating a hydrogen ion exponent (pH) of the carbon nanotube dispersed solution; a third step for manufacturing an alumina suspension; a fourth step for regulating a hydrogen ion exponent (pH) of the alumina suspension; a fifth step for mixing the carbon nanotube dispersed solution and the alumina suspension by using a stirrer; and a sixth step for ultrasound treating a mixture of the carbon nanotube dispersed solution and the alumina suspension.

Description

Technical Field [0001] The present invention relates to a method of manufacturing a carbon nanotube-alumina composite,

The present invention relates to a method for producing a carbon nanotube-alumina (CNT) -alumina composite, and more particularly, to a method for preparing a carbon nanotube-alumina The present invention relates to a method for producing a carbon nanotube-alumina composite,

Ceramics generally have many advantages such as heat resistance, abrasion resistance and chemical resistance, but they have weak defects in brittle fracture. It is a common practice to complement this and to form complexes for the enhancement of fracture toughness.

The carbon nanotube-ceramic composite can be formed by using carbon nanotubes having excellent mechanical properties, electrical selectivity, and excellent field emission properties as reinforcements in order to overcome the disadvantages of the ceramic when forming the composite.

However, since single-walled carbon nanotubes are generally surface atoms, aggregation due to van der Waals force between carbon nanotubes tends to occur, and a bundle or agglomerate structure composed of a plurality of carbon nanotubes And multi-walled carbon nanotubes are generally entangled with each other to form large agglomerates.

Due to the cohesion of such carbon nanotubes, chemical and physical manipulations and industrial application of carbon nanotubes are obstructed, and thus there is a growing need for a method of dispersing carbon nanotube aggregates.

Currently, research is actively underway to use carbon nanotubes as reinforcements in ceramics as well as polymers and metal composites. In the preparation of carbon nanotube-reinforced metal composite materials, the characteristics of carbon nanotubes were evaluated by mixing ceramic powder and carbon nanotube powder and sintering through hot press.

However, the conventional process for producing a composite of carbon nanotubes and ceramics is complicated and difficult, and it is difficult to disperse the carbon nanotubes due to cohesiveness of the carbon nanotubes, and the ceramic nanoparticles having a nanometer level of carbon nanotubes and agglomerates The carbon nanotube-ceramic composite may have a larger size and may be interfered with the incorporation thereof, so that the carbon nanotube-ceramic composite may have nonuniformity and can not exhibit the advantage as a composite.

Korean Patent Laid-Open No. 10-2010-0056998 A composite made of nanotube or nanofiber on? -SiC film.

DISCLOSURE Technical Problem The present invention has been conceived in order to solve the problems of the prior art as described above, and it is an object of the present invention to provide a condition for effectively mixing and dispersing carbon nanotubes and alumina, To thereby provide a method of manufacturing a carbon nanotube-alumina composite having a high fracture toughness.

A method of manufacturing a carbon nanotube-alumina composite according to an embodiment of the present invention includes: a first step of preparing a carbon nanotube dispersion; A second step of adjusting the pH of the carbon nanotube dispersion; A third step of preparing an alumina suspension; A fourth step of adjusting the pH of the alumina suspension; A fifth step of mixing the carbon nanotube dispersion and the alumina suspension using a stirrer; And a sixth step of ultrasonically treating the carbon nanotube dispersion and the alumina suspension mixture. And a control unit.

According to the present invention, the correlation between dispersion and dispersion conditions such as pH adjustment and zeta potential control of carbon nanotube dispersion and alumina suspension is grasped, and carbon nanotube-alumina having high fracture toughness Complex can be produced.

1 is a flowchart showing a method of manufacturing a carbon nanotube-alumina composite according to an embodiment of the present invention.
FIG. 2 is a graph illustrating changes in zeta potential of carbon nanotube dispersion and alumina according to pH, which are used in a method of manufacturing a carbon nanotube-alumina composite according to an embodiment of the present invention.
FIG. 3 is a photograph of a carbon nanotube-alumina composite according to an embodiment of the present invention after drying the CNT-Alumina mixed powder of Example 1 for one day.
FIG. 4 is a photograph of a CNT-Alumina mixed powder of Comparative Example 1 of the method for manufacturing a carbon nanotube-alumina composite according to an embodiment of the present invention, after drying for one day.
FIG. 5 is a photograph of a carbon nanotube-alumina composite according to an embodiment 1 of the present invention, measured by a scanning electron microscope (SEM). FIG.
FIG. 6 is a photograph of a carbon nanotube-alumina composite according to an embodiment of the present invention, in which Comparative Example 1 is measured by a scanning electron microscope (SEM).

The above and other objects, features and advantages of the present invention will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: FIG. BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention, and the manner of achieving them, will be apparent from and elucidated with reference to the embodiments described hereinafter in conjunction with the accompanying drawings.

The method for producing a carbon nanotube-alumina composite according to the present invention is to grasp the correlation between the zeta potential depending on the pH of the carbon nanotube dispersion and the alumina suspension and to prepare a carbon nanotube-alumina composite having high fracture toughness do.

Important factors that must be provided for this purpose include ensuring optimum CNT dispersion conditions in the slurry, adjusting the zeta potential of the alumina suspension and carbon nanotube dispersion, mixing and ultrasonic treatment through a stirrer To efficiently produce a carbon nanotube-alumina composite.

Hereinafter, a method of manufacturing the carbon nanotube-alumina composite as described above will be described with reference to the drawings and embodiments.

1 is a flowchart showing a method of manufacturing a carbon nanotube-alumina composite according to an embodiment of the present invention.

First, in a first step (S10), a carbon nanotube dispersion is prepared. Specifically, distilled water, carbon nanotube (CNT), and sodium dodecyl sulfate (SDS), an anionic surfactant, are mixed to prepare a carbon nanotube dispersion. The composition ratio of the carbon nanotube dispersion is 0.0001 part by weight of carbon nanotube (CNT) powder and 0.0001 part by weight of sodium dodecyl sulfate (SDS) powder per 1 part by weight of distilled water, which improves the dispersibility of carbon nanotube (CNT) (SDS) is less than 0.0001 part by weight, the dispersion of carbon nanotubes (CNTs) may not easily occur. When the amount of carbon nanotubes (CNTs) exceeds 0.0001 parts by weight, inherent properties of carbon nanotubes It is most preferable to keep the composition ratio in consideration of the range of the error.

Next, in the second step S20, the hydrogen ion index (pH) of the carbon nanotube dispersion is adjusted. Specifically, the carbon nanotube dispersion is adjusted to pH 7.

2 is a graph showing changes in zeta potential in a carbon nanotube dispersion according to pH. As shown in FIG. 2, it can be seen that the zeta potential of the carbonic acid nanotube dispersion added with SDS is -30 mV at pH 7. It is shown that the zeta potential decreases from a positive value to a negative value as the pH increases in the zeta potential change, which is a phenomenon caused by an increase in the OH-concentration with increasing pH.

In the production of carbon nanotube-alumina composite, the zeta potential size according to the pH of the carbon nanotube dispersion and alumina suspension can be checked and controlled to effectively control the dispersion due to electrostatic repulsion.

Next, in the third step (S30), an alumina suspension is prepared. Specifically, the alumina powder is mixed with distilled water and stirred for 30 minutes to 40 minutes to prepare a suspension.

In the production of the alumina suspension, the composition ratio of the alumina powder and the distilled water is 0.01 to 0.03 parts by weight of alumina based on 1 part by weight of distilled water. The limited range of the alumina powder and the distilled water can be varied depending on the purpose of using the carbon nanotube-alumina composite.

Next, in step S40, the hydrogen ion index (pH) of the alumina suspension is adjusted. Specifically, the alumina suspension is adjusted to pH 7.

Next, in the fifth step, the carbon nanotube dispersion and the alumina suspension are mixed using a stirrer. Specifically, the pH-adjusted carbon nanotube dispersion and alumina suspension are mixed using a stirrer for 30 minutes to 40 minutes. When the mixing time is less than 30 minutes, the mixing may not be completed completely, and when the mixing time exceeds 40 minutes, the mixing is completed and the efficiency is lowered.

Next, in the sixth step S60, the carbon nanotube dispersion and the alumina suspension mixture are ultrasonicated. Specifically, the carbon nanotube dispersion and the alumina suspension mixture are ultrasonicated for 30 minutes to 40 minutes. When the ultrasonic treatment time is less than 30 minutes, the carbon nanotubes are not completely dispersed. If the ultrasonic treatment time is more than 40 minutes, the dispersion is completed and the efficiency is lowered and the carbon nanotubes may be damaged due to excessive ultrasonic treatment. It is preferable to proceed to the time within the range.

In the present invention, the experiment contents of the carbon nanotubes dispersed under the predetermined conditions as described below using the carbon nanotube dispersion method described above will be described in detail using Comparative Examples 1 and 1.

≪ Comparative Example 1 &

In Comparative Example 1, 200 g of distilled water, 0.2 g of CNT and 0.2 g of SDS were mixed to prepare a carbon nanotube dispersion. After the pH was not adjusted, alumina without pH control was added thereto. The mixture was stirred in a stirrer for 30 minutes, Ultrasonic treated carbon nanotube-alumina composite.

≪ Example 1 >

Example 1 is prepared by mixing 200 g of distilled water, 0.2 g of CNT and 0.2 g of SDS to prepare a carbon nanotube dispersion, and then adjusting the pH to 7 and the zeta potential to -30 mV. The alumina suspension was adjusted to pH 7, zeta potential + 30 mV, stirred for 30 minutes in a stirrer, and sonicated for 30 minutes to obtain a carbon nanotube-alumina composite.

In order to demonstrate the correlation between the zeta potential of the carbon nanotube dispersion and the alumina suspension in the method of preparing the carbon nanotube-alumina composite of the present invention in Example 1 and Comparative Example 1, The results are shown in Fig. 3 to Fig.

A. Confirm dispersion

The carbon nanotube-alumina composite of the present invention is dried in a CNT-Alumina powder for a day to be visually observed in order to confirm the dispersion of the carbon nanotube-alumina composite of the present invention in FIG. 3 to FIG.

FIG. 3 is a photograph of a carbon nanotube-alumina composite according to an embodiment of the present invention after drying the CNT-Alumina mixed powder of Example 1 for one day.

FIG. 4 is a photograph of a CNT-Alumina mixed powder of Comparative Example 1 of the method for manufacturing a carbon nanotube-alumina composite according to an embodiment of the present invention, after drying for one day.

In Example 1 of FIG. 3, CNT-Alumina was uniformly dispersed with high dispersion. In Comparative Example 1 of FIG. 4, CNT-Alumina was dispersed and aggregated unevenly.

The CNT-Alumina of Comparative Example 1 is difficult to be uniformly mixed and dispersed, and the CNT-Alumina of Example 1 has a zeta potential CNT of -30 mV and Alumina + 30 mV, resulting in more uniform mixing and dispersion .

Therefore, it can be seen that the CNT-Alumina dispersibility can be improved by controlling the pH, which is closely related to the zeta potential.

N. Scanning Microscope (SEM) Measurement

SEM measurement results of the carbon nanotube-alumina composite of the present invention in Example 1 and Comparative Example 1 are shown in FIGS. 5 to 6.

FIG. 5 is a photograph of a carbon nanotube-alumina composite according to an embodiment 1 of the present invention, measured by a scanning electron microscope (SEM). FIG.

FIG. 6 is a photograph of a carbon nanotube-alumina composite according to an embodiment of the present invention, in which Comparative Example 1 is measured by a scanning electron microscope (SEM).

As a result of the SEM measurement, it can be seen that the carbon nanotube-alumina composite of Example 1 shown in FIG. 5 has much higher dispersion and homogeneous dispersion than the carbon nanotube-alumina composite shown in FIG.

It can be seen that the carbon nanotube-alumina composite has a high dispersibility through pH control, and the dispersion of carbon nanotube-alumina (CNT-Alumina) is controlled by the pH of the carbon nanotube dispersion and the alumina suspension It is proved that the CNT and Alumina surfaces have higher dispersibility by giving electrical properties to the surface through control.

As described above, it is to be understood that the technical structure of the present invention can be embodied in other specific forms without departing from the spirit and essential characteristics of the present invention.

It is to be understood, therefore, that the above description is intended to be illustrative, and not restrictive, and that the scope of the present invention is defined by the appended claims rather than by the foregoing description, All changes or modifications that come within the scope of the equivalent concept are to be construed as being included within the scope of the present invention.

S10. Carbon nanotube dispersion is the first step to manufacture.
S20. And a second step of controlling pH of the carbon nanotube dispersion.
S30. The third step of preparing an alumina suspension.
S40. And a fourth step of controlling the pH of the alumina suspension.
S50. And a fifth step of mixing the carbon nanotube dispersion and the alumina suspension using a stirrer.
S60. And a sixth step of ultrasonifying the carbon nanotube dispersion and the alumina suspension mixture.

Claims (6)

A first step of preparing a carbon nanotube dispersion;
A second step of adjusting the pH of the carbon nanotube dispersion;
A third step of preparing an alumina suspension;
A fourth step of adjusting the pH of the alumina suspension;
A fifth step of mixing the carbon nanotube dispersion and the alumina suspension using a stirrer; And
A sixth step of ultrasonifying the carbon nanotube dispersion and the alumina suspension mixture; Wherein the carbon nanotube-alumina composite comprises a carbon nanotube-alumina composite. The method according to claim 1,
Wherein the carbon nanotube dispersion in the first step is prepared by mixing 0.001 part by weight of CNT and 0.001 part by weight of SDS per 1 part by weight of distilled water. The method according to claim 1,
Wherein the carbon nanotube dispersion has a pH of 7.0 and a zeta potential of -30 mV in the second step. The method according to claim 1,
Wherein the pH of the alumina suspension in the fourth step is 2.0 and the zeta potential is +30 mV. The method according to claim 1,
Wherein the carbon nanotube dispersion and the alumina suspension in the fifth step are agitated for 30 minutes to 40 minutes. The method according to claim 1,
Wherein the ultrasonic treatment of the carbon nanotube dispersion and the alumina suspension mixture in the sixth step is performed for 30 minutes to 40 minutes.

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