JPH11349307A - Production of functional carbonaceous material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a carbon nanotube, a fullerene, a particulate diamond, a hollow onionlike carbon or a metal-enclosing onionlike carbon in high yield and high purity and further directly form a thin film thereof on a substrate. SOLUTION: A polytetrafluoroethylene, a polyvinylidene chloride or a polyvinylidene fluoride is irradiated with at least one kind of light, electron beams and ion beams or the polytetrafluoroethylene, polyvinylidene chloride or polyvinylidene fluoride is subjected to irradiating treatment and heat treatment to thereby produce an amorphous carbon containing at least one kind of a carbon nanotube, a fullerene, a particulate diamond, a hollow onionlike carbon and a metal-enclosing onionlike carbon.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a functional carbon material such as carbon nanotubes, fullerenes, fine diamond particles, hollow onion-like carbon, and metal-containing onion-like carbon.

[0002] In the present invention, the term "hollow onion-like carbon" means spherical or polyhedral carbon particles having a hollow central portion and an onion-like graphite laminated structure developed around the central portion. . In such hollow onion-like carbon, the graphite layer is laminated in several layers to several tens layers.

[0003] The term "hollow onion-like carbon containing metal" refers to spherical or polyhedral carbon particles in which metal particles are present in the center of the above-mentioned "hollow onion-like carbon". The metal included is
Although not particularly limited, for example, Mg, Al, Au and the like are exemplified.

[0004]

2. Description of the Related Art Carbon nanotubes (hereinafter sometimes simply referred to as "nanotubes") and fullerenes are produced by using a carbon material such as amorphous carbon or graphite as a raw material in the presence of a catalytic metal, using a carbon arc method, a sputtering method, or a laser beam. It is synthesized by a gas phase method such as an irradiation method (Japanese Patent Application Laid-Open Nos. 6-157016, 6-280116, 6-227806, 6-283129, 6-283129).
-322615, JP-A-6-325623, JP-A-7-19732
5, JP-A-7-165406, JP-A-8-188406, JP-A-9-31757, etc.). However,
In these methods, graphite and amorphous carbon other than the nanotubes are mixed in the product, so that not only the yield is low, but also the incorporation of a catalytic metal into the nanotubes cannot be avoided. In addition, since nanotubes and fullerenes are generated in a mixed state in the generated soot, it has been difficult to form a thin film on a substrate.

[0005]

Accordingly, the present invention provides carbon nanotubes, fullerenes,
The main purpose is to form fine-particle diamond, hollow onion-like carbon, or metal-containing onion-like carbon.

Another object of the present invention is to form these thin films directly on a substrate.

[0007]

Means for Solving the Problems The present inventor has conducted research in view of the state of the art as described above, and as a result, has found that light, electron, and light are not applied to polytetrafluoroethylene, polyvinylidene chloride or polyvinylidene fluoride. By irradiating at least one of a line and an ion beam, or by subjecting them to irradiation treatment and heat treatment, carbon nanotubes, fullerenes, fine-particle diamonds,
A technique for forming hollow onion-like carbon, metal-containing onion-like carbon, or a mixture thereof has been completed.

That is, the present invention provides the following method for producing a functional carbon material.

1. By irradiating at least one of light, an electron beam and an ion beam to polytetrafluoroethylene, polyvinylidene chloride or polyvinylidene fluoride, or by subjecting them to irradiation treatment and heat treatment, carbon nanotubes, fullerenes,
A method for producing a functional carbon material, comprising generating amorphous carbon containing at least one of fine-particle diamond, hollow onion-like carbon, and metal-containing onion-like carbon.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the production of a functional carbon material such as carbon nanotubes by a conventional arc discharge method, a carbon arc is generated in a helium gas using a carbon material such as amorphous carbon or graphite as an electrode, and a cathode surface is produced. (Japanese Patent Laid-Open Publication No. 6-15
7016 publication etc.). That is, for example, when a stable arc discharge is maintained while maintaining the gap between the carbon electrodes at about 1 mm, a columnar deposit having a diameter substantially equal to the diameter of the anode rod is formed at the tip of the cathode. When the anode carbon rod is 6 mm in diameter and the arc current is 70 A (voltage is 25 V), the deposit grows at a rate of about 2 to 3 mm per minute, and helium contains about 500 t
Maximum yield is obtained at orr. Next, a method of dispersing the deposit on the tip of the cathode in ethanol using ultrasonic waves or the like and separating by ethanol, a filter, a column separation, or the like is common. Therefore, it is impossible to form a functional carbon material thin film.

On the other hand, in the present invention, a film-like polytetrafluoroethylene (PTFE), polyvinylidene chloride or polyvinylidene fluoride is irradiated with at least one of light, an electron beam and an ion beam. Alternatively, by subjecting the resin film to irradiation treatment and heat treatment, the resin film is directly carbonized to form carbon nanotubes, hollow onion-like carbon, metal-containing onion-like carbon, or a mixture thereof.
A mixture of more than one species is formed.

In the method of the present invention, since these functional carbon materials are formed on the surface of the resin film, the separation and purification thereof are easier than in the prior art, and the thin film is impossible in the prior art. Is realized.

When the raw material is irradiated with light, a laser having a wavelength of about 300 to 1200 nm, an output of about 0.1 to 10 mJ / cm ² , more preferably a wavelength of about 400 to 800 nm, and an output of about 0.5 to ⁵ mJ / cm ² is preferred. Use light. The type of laser light can be any of those commonly used, and is not particularly limited.For example, Nd: YAG laser, Ti: Sa laser, Dye laser, Dye + SHG laser, Ar ⁺ laser, Kr ⁺ Laser and the like.

That is, the present invention provides a method for producing a functional carbon material described below.

When the raw material is irradiated with an electron beam, it is usually about 10 ⁻² to 10 ⁻⁷ torr (more preferably 10 ⁻³ to 1 torr).
Under a reduced pressure of about 0 ^-5 torr), irradiation is carried out at an acceleration voltage of about 1～2000KV (more preferably about 50~1000kV).

[0016] When performing the ion beam irradiation, material vacuum chamber (typically 10 ⁰ to 10 ^-4 torr, more preferably about 10 ^-1 to 10 under reduced pressure of about ^-3 torr) was placed in and allowed to ionizing Acceleration voltage 100V ~ 10 using He ion or Ar ion
kV (more preferably about 200 V to 1 kV) and ion current about 0.01 to 100 mA / cm ² (more preferably 0.1 to 10 mA / cm ²
Irradiation).

When irradiation is performed to impart reaction energy to the raw material, it is more preferable to use laser light as the irradiation source.

Further, at the time of processing the raw material, at least one of the above-described irradiation treatments and a heat treatment may be used in combination. When heating the raw material, usually under reduced pressure of about 10 ^-1 to 10 ^-6 torr (more preferably under a pressure of about 760 to 10 ^-3 torr)
About 100 to 2000 ° C (more preferably, about 200 to 1500 ° C)
Heat with. Or He or Ar of about 760 to 10 ^-4 torr
About 100-2000 ° C in atmosphere (more preferably, 200-1500
(About ° C).

Next, the irradiated resin film is subjected to, for example, ultrasonic cleaning in a solvent such as ethanol, tetrahydrofuran or diethyl ether to remove by-products such as soot.
Obtain the desired functional carbon material.

When PTFE is used as the resin, it is known that a polyyne structure is formed by reduction. Therefore, irradiation with at least one of light, electron beam and ion beam, or irradiation treatment and heating It is presumed that polyyne is formed on the film surface and / or inside the film by subjecting the film to the treatment, and this forms a functional carbon material such as carbon nanotubes.

The metal-containing onion-like carbon is formed when metal particles exist inside and / or on the surface of the resin film. That is, by irradiating the resin film containing metal particles with at least one of light, electron beam, and ion beam in the same manner as described above, or by subjecting the resin film to irradiation treatment and heat treatment, the metal particles become onion. It is taken into the hollow portion of the like carbon to form metal-containing onion-like carbon. The application of the metal particles to the resin film is performed by a method such as plating a metal on the resin film surface by a known resin plating technique, or kneading metal fine particles (10 μm or less) in advance in the resin material during film production. I can do it.

Further, the hollow onion-like carbon is
By heating the above-mentioned metal-containing onion-like carbon under reduced pressure, the metal can be melted and vaporized / removed to produce the metal.

[0023]

According to the present invention, the following remarkable effects are achieved.

(1) A resin film of polytetrafluorocarbon, polyvinylidene chloride, polyvinylidene fluoride or the like is used as a raw material, and carbon nanotubes, fullerene, diamond fine particles, hollow onion-like carbon, metal-containing hollow onion-like carbon, etc. are used on the surface thereof. The product is easy to purify and separate.

(2) Since the functional carbon material is formed on the surface of the resin film, these functional thin films can be formed on the substrate.

(3) The carbon nanotube thin film and the like thus obtained exhibit theoretically predicted electronic physical properties and chemical properties.

(4) The obtained carbon nanotube thin film is made of a wear-resistant material, an electron beam emitting emitter, a highly directional radiation source, a soft X-ray source, a one-dimensional conductive material, a high thermal conductive material, and other electronic materials. It is also useful as a material.

[0028]

EXAMPLE 1 A polytetrafluoroethylene film was embedded in an epoxy resin, and a transmission electron microscope (TE) was used with a microtome.
M: HITACHI H7100) after cutting for electron beam irradiation treatment with, under high vacuum of 10 ^-6 torr, the sample holder 300
C. and irradiated with an electron beam at an acceleration voltage of 100 kV.

A few minutes after the start of the electron beam irradiation, the film is burnt and has holes. The film was collected, ultrasonically washed in ethanol to remove soot-like carbon, and then observed with a transmission electron microscope. This confirmed that carbon nanotubes and hollow onion-like carbon were formed on the PTFE film surface.

This is presumably because PTFE was carbonized by electron beam irradiation, and the carbonized material was further heated to form nanotubes and onion-like carbon.

Alternatively, it has already been pointed out that in the synthesis of nanotubes and the like, there is a possibility of passing through polyyne as an intermediate thereof. Since PTFE is known to form a polyin structure by reduction, also in this example, polyin is first formed on the film surface and / or in the film by electron beam irradiation, and this is further transformed into nanotubes and onion-like carbon. It is thought that it was done.

Example 2 A cylindrical polyvinylidene chloride film having a diameter of 20 mm and a length of 20 mm was prepared and subjected to electron beam irradiation in the same manner as in Example 1. Next, when the carbonized film was subjected to ultrasonic cleaning in ethanol and then observed with a transmission electron microscope, carbon nanotubes and onion-like carbon were observed.

It is known that polyvinylidene chloride takes a polyyne structure by reduction like PTFE. Also in this example, it is considered that this polyin became an intermediate and changed into nanotubes and onion-like carbon.

Example 3 A cylindrical polyvinylidene fluoride film having a diameter of 20 mm and a length of 20 mm was prepared and subjected to electron beam irradiation in the same manner as in Example 1. Next, when the carbonized film was subjected to ultrasonic cleaning in ethanol and then observed with a transmission electron microscope, carbon nanotubes and onion-like carbon were observed.

Also in this example, it is considered that polyin became an intermediate and changed into nanotubes and onion-like carbon.

Example 4 Five polytetrafluoroethylene films (30 mm × 100 mm × 30 μm) were charged into an aqueous ferric chloride solution (0.1 mol / l), and a hydrazine aqueous solution (0.1 mol / l) was mixed. Were plated with iron. The obtained iron-plated PTFE film was irradiated with an electron beam in the same manner as in Example 1, then washed with ethanol, and observed with a transmission electron microscope.

As a result, many hollow onion-like carbons containing iron fine particles were observed. It was found that the method of the present invention is effective as one of the methods for producing hollow onion-like carbon containing metal particles.

Example 5 A polytetrafluoroethylene film (30 mm × 100 mm × 30 μm) was added to an aqueous solution of magnesium chloride (0.1 mol / l).
The sheets were charged, an aqueous hydrazine solution (0.1 mol / l) was mixed in, and both surfaces of the film were plated with magnesium. The obtained magnesium-plated PTFE film was irradiated with an electron beam in the same manner as in Example 4, and then observed with a transmission electron microscope. At this stage, a large number of hollow onion-like carbons containing magnesium fine particles were observed.

Next, the sample holder of the electron microscope was set to 800
When the temperature was raised to ° C., magnesium particles were vaporized and removed, and formation of hollow onion-like carbon was observed.
Therefore, it was found that the method of the present invention is effective as a method for producing hollow onion-like carbon.

Example 6 An ion beam (Kauffman-type ion source: argon ion beam, acceleration voltage: 500) was applied to a polytetrafluoroethylene film in a vacuum chamber (4 × 10 ^-2 torr).
V, ion current density: 1 mA / cm ² ) for 10 minutes.

This sample was extracted with toluene, concentrated, and separated by HPLC (column: Cosmoseal Buckypr.
ep packed column). ¹³ C-NMR confirmed that fullerene had been formed.

Example 7 A laser beam (Nd: YAG Laser: 632 nm, 2 mJ / p) was applied to a polytetrafluoroethylene film under reduced pressure (10 ^-5 torr).
ulse · cm ² , 10 Hz).

As a result of analyzing the sample by electron beam diffraction and X-ray diffraction, it was confirmed that diamond was formed. As a result of SEM observation, the diamond formed in this example was a fine particle diamond having a size of several μm or less.

Example 8 A polytetrafluoroethylene film was placed on a heating holder in a vacuum vessel, and heated to 800 ° C. under reduced pressure (1
0 ^-5 torr) with a laser beam (Nd: YAG Laser: 632nm, 2mJ / puls
e · cm ² , 10 Hz). As a result of analyzing this sample by electron beam diffraction and X-ray diffraction, it was confirmed that diamond was formed. The diamond obtained in this example is different from the diamond formed in Example 7,
It was confirmed by SEM observation that a thin film having a thickness of 0.3 μm was formed on the surface of the carbon material.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Terumitsu Kadomoto 4-1-2, Hirano-cho, Chuo-ku, Osaka-shi, Osaka Inside Osaka Gas Co., Ltd. 17 Kyoto Research Park Kansai New Technology Laboratory Co., Ltd.

Claims (1)

[Claims] 1. By irradiating at least one of light, an electron beam and an ion beam to polytetrafluoroethylene, polyvinylidene chloride or polyvinylidene fluoride, or by subjecting them to irradiation treatment and heat treatment, A method for producing a functional carbon material, comprising producing amorphous carbon including at least one of carbon nanotube, fullerene, fine-particle diamond, hollow onion-like carbon, and metal-containing onion-like carbon.