KR101338033B1 - Aramid composites reinforced with mixed carbon nanomaterials of graphene and carbon nanotube and process for producing the same - Google Patents

Abstract

According to the present invention, even when the weight ratio of the mixed carbon nanotubes in which graphene and carbon nanotubes are mixed with the aramid polymer in the aramid / graphene / carbon nanotube composite is the same, the mixing ratio of graphene and carbon nanotubes is variously controlled. To provide aramid / graphene / carbon nanotube composites that can control the thermal, mechanical and electrical properties of the aramid / graphene / carbon nanotube composites and aramid / graphene / carbon nanotube composites prepared accordingly For the purpose, the technical configuration, characterized in that the aramid / graphene / carbon nanotube composite by producing a mixture of carbon nanoparticles and aramid polymer mixed with graphene and carbon nanotubes.

Description

Method for producing aramid / graphene / carbon nanotube composites and aramid / graphene / carbon nanotube composites prepared according to the present invention {Aramid composites reinforced with mixed carbon nanomaterials of graphene and carbon nanotube and process for producing the same}

The present invention relates to a method for producing an aramid complex and the resulting aramid complex, and more specifically, aramid / graphene / to prepare aramid complex by solution-mixing carbon nanoparticles mixed with graphene and carbon nanotubes to an aramid polymer The present invention relates to a method for preparing a nasano nanotube composite and an aramid / graphene / carbon nanotube composite prepared accordingly.

Aramid refers to an aromatic polyamide fiber, and refers to a wholly aromatic polyamide having a molecular structure in which at least 85% or more of amide bonds (-CONH-) are bonded between aromatic rings.

Such aramid is divided into para aramid represented by the following [Formula 1] and meta aramid represented by [Formula 2].

[Formula 1]

(2)

Here, para aramid is used in the field requiring high strength and high elasticity, which is competitive in price, because it has very excellent tensile strength, elastic modulus, and heat resistance compared to ordinary organic fibers, and meta aramid has excellent heat resistance and flame retardancy, but In terms of physical properties such as elongation and elastic modulus, most of them are similar to conventional polyesters.

In addition, para aramids are processed by dissolving them in toxic and dangerous organic solvents such as strong sulfuric acid, while meta aramids are organic solvents such as dimethylformamide, dimethylacetamide, dimethyl sulfoxide, N-methyl-2-pyrrolidone, and the like. It can be melted and processed.

On the other hand, aramid fibers, including yarns and fabrics in the form of nonwovens, laminating, staples, paper, etc., with high elastic modulus, excellent strength, rigidity, chemical resistance, low electrical conductivity, shrinkage, dimensional stability, cutting Due to its properties such as resistance and flame retardancy, it is used for various composite materials such as fiber reinforced rubber composite materials, composite materials such as ropes, cables, antiballistic protection and friction materials, and leisure-sport equipment.

In addition, it is being widely used in various related industries such as automobile, information and communication, aerospace, defense, leisure and special industries, and is attracting attention as a high value-added material.

In addition, aramid film and plastic are used as magnetic tape, release film, adhesive tape, insulating material and composite materials.

Graphene, on the other hand, has a large surface area in the form of a plate with carbon atoms arranged like a honeycomb hexagonal net. Graphite has a structure in which graphene is stacked and stacked.

Here, graphene has a high electrical conductivity of ~ 10 ⁴ S / cm, has an excellent Young's modulus of ~ 1 TPa, has a very high thermal stability, carbon nanotubes and similar thermal, mechanical and electrical properties In comparison, the price is very low.

Meanwhile, carbon nanotube (CNT) is a material that is spotlighted as an almost perfect new material without defects among existing materials, and its electrical conductivity is similar to that of copper, and the thermal conductivity is the most excellent diamond in nature. Is 100 times better than steel.

The carbon fiber is cut even when only 1% is deformed, whereas the carbon nanotube is very stable enough to withstand 15% deformation. Here, the carbon nanotubes have a plate-shaped graphene sheet roundly dried to a diameter of nanometer size, and show the characteristics of a metal or a semiconductor depending on the angle and structure of the graphene sheet being dried.

In addition, single-walled carbon nanotubes (hereinafter referred to as "SWCNT") and multi-walled carbon nanotubes (hereinafter referred to as "MWCNT"), depending on the number of bonds forming a wall. Separate by. The background technology of the present invention is disclosed in US Patent Application Publication No. US2011 / 0024158 and Korean Patent Publication No. 10-2010-0108868.

United States Patent Application Publication No. US2011 / 0024158 Republic of Korea Patent Publication No. 10-2010-0108868

The present invention has been made to solve the problems described above, graphene, single-walled carbon nanotubes (SWCNT: Single-walled carbon nanotube), multi-walled carbon nanotubes (MWCNT) and various Graphene, surface-modified carbon nanotubes (SWCNT), multi-walled with chemical species (compounds containing alkyl, allyl, carboxyl, hydroxyl, amine, epoxy, urethane, urea, etc.) Carbon nanoparticles mixed with one type of graphene and one type of carbon nanotubes selected from the group consisting of multi-walled carbon nanotubes (MWCNT) are used as functional reinforcing agents, and aramids having aramid polymer as matrix An object of the present invention is to provide a method for preparing a graphene / carbon nanotube composite and an aramid / graphene / carbon nanotube composite prepared accordingly.

In addition, the present invention, even if the weight ratio of the mixed carbon nanotubes in which the graphene and carbon nanotubes are mixed with the aramid polymer in the aramid / graphene / carbon nanotube composite, the mixing ratio of graphene and carbon nanotubes vary To control the thermal, mechanical and electrical properties of the aramid / graphene / carbon nanotube composite to control the aramid / graphene / carbon nanotube composite and aramid / graphene / carbon nanotube composite prepared accordingly The purpose is to provide.

In order to achieve the object as described above, the present invention, a mixture of carbon nanoparticles and aramid polymer in which graphene and carbon nanotubes are mixed to prepare an aramid / graphene / carbon nanotube composite.

According to a preferred embodiment of the present invention, the molecular chain structure of the aramid polymer is made to have at least 85% or more of at least one structure selected from the group consisting of repeating units of the following structural formula.

According to another suitable embodiment of the present invention, the composition ratio of the carbon nanoparticles mixed with the graphene and carbon nanotubes is 0.01 to 50.0% by weight based on the total weight of the composite, graphene: carbon nano to constitute the mixed carbon nanoparticles The weight ratio of the tubes consists of 0.001: 99.999 to 99.999: 0.001.

According to another suitable embodiment of the present invention, the graphene is surface modified with one or two or more compounds selected from the group consisting of alkyl group, allyl group, carboxyl group, hydroxyl group, amine group, epoxy group, urethane group, and urea group compound Is a graphene, and the carbon nanotube is surface-modified SWCNT or MWCNT with one or two or more compounds selected from the group consisting of alkyl, allyl, carboxyl, hydroxyl, amine, epoxy, urethane, and urea compounds to be.

According to another suitable embodiment of the present invention, the solution mixture of the aramid / graphene / carbon nanotube complex is water, dimethylformamide, dimethylacetamide, sulfuric acid, dimethyl sulfoxide, N-methyl at a temperature of 0 to 150 ℃ It is prepared using at least one solvent selected from the group consisting of -2-pyrrolidone and at least one salt selected from the group consisting of LiCl and CaCl ₂ .

According to another suitable embodiment of the present invention, the aramid / graphene / carbon nanotube composite is manufactured by the method, characterized in that it is included in a fiber, film or plastic product.

As described above, the present invention having the configuration as described above has superior thermal stability, mechanical properties, electrical conductivity, and heat generation characteristics than the aramid homopolymer, and therefore, even when applied to fibers, films, plastics, etc. Mechanical properties, electrical conductivity and electrical heating properties can be maintained and the like.

1 is a view showing the volume electrical resistance of the aramid / graphene / carbon nanotube composite according to the present invention,
Figure 2 is a view showing the timely heat generation characteristics with time under various applied voltage conditions of the aramid / graphene / carbon nanotube composite according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The present invention is not limited to the scope of the present invention, but is merely an example, and various modifications can be made without departing from the technical spirit of the present invention.

"Aramid / graphene / carbon nanotubes" applied to the present invention refers to a material prepared by combining a graphene and carbon nanotube mixed adjuvant in the aramid polymer, "Aramid" described in the present invention is 85 Refers to synthetic polymers in which at least% amide bonds (-CONH-) are directly connected to two aromatic rings.

The aramid applied to the present invention preferably has a molecular chain structure of 85% or more of at least one structure selected from the group consisting of repeating unit structures shown in the following [Formula 3] to [Formula 6].

(3)

[Chemical Formula 4]

[Chemical Formula 5]

[Chemical Formula 6]

Graphene applied to the present invention is a plate-like particle having a planar structure in which carbon atoms form a hexagonal honeycomb shape, and is excellent in heat resistance, electrical conductivity, thermal conductivity, and mechanical properties.

In addition, graphene can be surface modified with various chemical species (compounds including alkyl groups, aryl groups, carboxyl groups, hydroxyl groups, amine groups, epoxy groups, urethane groups, urea groups, and the like).

On the other hand, carbon nanotubes are carbon particles in the form of a cylindrical graphene sheet rolled into a cylinder, and single-walled carbon nanotubes (hereinafter referred to as 'SWCNT') and multi-walled carbon nanotubes (Multi- walled carbon nanotubes (hereinafter referred to as 'MWCNT').

As described above, carbon nanotubes made of SWCNT and MWCNT can be surface modified with various chemical species (compounds including alkali groups, allyl groups, carboxyl groups, hydroxyl groups, amine groups, epoxy groups, urethane groups, urea groups, etc.) Excellent electrical conductivity, heat resistance and mechanical properties.

Hereinafter, the preparation method of the aramid / graphene / carbon nanotube composite according to the present invention.

To this end, a method of manufacturing graphene applied to the present invention will be described first.

Here, the method for producing graphene, but first carbon nanoparticles and aramid homopolymers are mixed with graphene and carbon nanotubes, the carbon nanoparticles and aramid homopolymers are 0.001 to 99.999: 99.999 to 0.001% by weight It is preferable to prepare in various combinations from, but more preferably the carbon nanoparticles are prepared by combining in a range of 0.01 to 50.00% by weight relative to the total weight of the composite.

Here, the mixing of the carbon nanoparticles and the aramid polymer in which the graphene and the carbon nanotubes are mixed in various weight ratios is preferably performed by solution mixing.

The solution mixing is preferably carried out using a solvent such as water, dimethylformamide, dimethylacetamide, sulfuric acid, dimethyl sulfoxide and N-methyl-2-pyrrolidone or mixed solvents thereof.

In particular, in order to improve the solubility of aramid during solution mixing, it is preferable to add a salt such as LiCl or CaCl ₂ in an amount of 0.01 to 50.00% by weight, and more preferably 0.1 to 20.0% by weight.

In addition, the solution mixing is preferably carried out at a temperature range of 0 to 150 ℃, wherein the weight of the solvent is more preferably made of 20.00 to 99.99% by weight relative to the weight of the total solution.

Example  1-9 and Comparative Example  One

Aramid polymer for the present invention was used by Sigma Aldrich Co., Ltd. product. As one of the carbon nanoparticles, graphene was directly prepared by acid treatment and thermal expansion (1050 ° C., 30 seconds) using natural graphite purchased from Sigma Aldrich Co., Ltd.

Carbon nanotubes as another carbon nanoparticles were manufactured by Hanwha Nanotech's MWCNT (model name: CM-250), and products having a diameter of 10 to 15 nm were used.

Dimethylacetamide and LiCl were used as a solvent and a salt in solution mixing.

In the solution mixture, the ratio of aramid and mixed carbon nanoparticles: solvent: salt was stirred at 80 ° C. for about 24 hours at a weight ratio of 10: 88: 2.

The weight ratio of the aramid polymer and the mixed carbon nanoparticles (graphene + MWCNT) in the solution mixture was 99.0: 1.0, the relative weight ratio of graphene and MWCNT in the mixed carbon nanoparticles is various as shown in Table 1 below Adjusted.

The prepared solution mixture was uniformly dispersed carbon nanoparticles (graphene + MWCNT) through the sonication and stirring process.

An appropriate amount of solution mixture is poured into a chale, followed by air drying and vacuum drying at a temperature of 80 to 160 ° C., washing with distilled water at 80 ° C. to completely remove the solvent, thereby obtaining aramid / graphene / MWCNT having a thickness of about 0.1 mm. The complex was prepared.

Aramid
(weight%) Carbon nanoparticles
(Graphene + MWCNT)
(weight%) Graphene: MWCNT
(Weight ratio) Comparative Example 1 100 - - Example 1 99.0 1.0 100: 0 Example 2 99.0 1.0 90:10 Example 3 99.0 1.0 80:20 Example 4 99.0 1.0 70:30 Example 5 99.0 1.0 50:50 Example 6 99.0 1.0 30:70 Example 7 99.0 1.0 20:80 Example 8 99.0 1.0 10:90 Example 9 99.0 1.0 0: 100

Experimental Example  1 (conductivity measurement)

An electrical resistance meter (Keithley 8009 resistivity test fixture, Keithley 2400 sourcemeter / 2181 nanovoltmeter) was used to measure the electrical conductivity of the aramid / graphene / MWCNT composite.

As shown in Comparative Example 1, the aramid homopolymer exhibited a volume electrical resistance value of ˜10 ¹⁶ Ω · cm.

1 is a view showing the volume electrical resistance of the aramid / graphene / carbon nanotube composite according to the present invention, aramid / carbon nanoparticles introduced 1.0 wt% carbon nanoparticles mixed with graphene and MWCNT of various weight ratios It is a figure which shows the volume resistance of a composite.

As shown in the figure, the electrical conductivity of the aramid / graphene / MWCNT composite from the mixed carbon nanoparticles (graphene + MWCNT) as a result of the change in the volumetric resistance value of the composite according to the weight ratio change of MWCNT It can be seen that it can be easily controlled according to the composition ratio of the carbon nanoparticles.

For example, as shown in Example 1, when the weight ratio of graphene: MWCNT is 100: 0, the volume resistivity of the aramid / graphene / MWCNT composite shows ˜10 ¹⁰ Ω.cm, while As shown in Example 2, when the weight ratio of graphene: MWCNT is 90:10, the volume electrical resistance of the aramid / graphene / MWCNT composite shows ˜10 ⁵ Ω.cm, as shown in Example 9, When the weight ratio of fin: MWCNT is 0: 100, it can be seen that the volume electrical resistance of the aramid / graphene / MWCNT composite decreases rapidly, such as ˜10 ¹ Ω.cm.

From this, it can be seen that as the content of MWCNT increases in the mixed carbon nanoparticles (graphene + MWCNT), the volume electrical resistance of the composite is continuously lowered.

Experimental Example  2( Electricity generation  Characteristic measurement)

The electrothermal properties of the aramid / graphene / MWCNT composites were measured using a thermal imaging camera.

2 is a view showing the timely heat generation characteristics with time under various applied voltage conditions of the aramid / graphene / carbon nanotube composite according to the present invention, as shown in Example 6, the weight ratio of graphene: MWCNT is 30: The aramid / graphene / MWCNT composite containing 70 wt% of mixed carbon nanoparticles was shown to increase in temperature with time of the composite when various voltages of 7 to 90 [V] were applied at 25 ° C. at room temperature.

Unlike aramid / graphene / MWCNT or aramid / MWCNT complex, it can be seen that in the case of the aramid homopolymer and the aramid / graphene complex, a temperature increase due to an applied voltage does not occur.

The aramid / graphene / MWCNT nanocomposite prepared according to the method for preparing the arimid / graphene / carbon nanotube composite according to the present invention has superior electrical conductivity and electrical conductivity as compared to conventional aramid homopolymers, as demonstrated in the above experimental example. In addition to exothermic properties, it has improved heat resistance and mechanical properties.

Therefore, it can be usefully applied to various fields such as film, fiber and plastic.

While the present invention has been particularly shown and described with reference to specific embodiments thereof, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims. It will be easy for anyone to know.

Claims (6)

To prepare aramid / graphene / carbon nanotube composite by mixing the carbon nanoparticles and aramid polymer mixed with graphene and carbon nanotubes,
The solution mixture of the aramid / graphene / carbon nanotube complex is in the group consisting of water, dimethylformamide, dimethylacetamide, sulfuric acid, dimethyl sulfoxide, N-methyl-2-pyrrolidone at a temperature of 0 to 150 ℃ A method for producing an aramid / graphene / carbon nanotube complex, characterized in that it is prepared using at least one solvent selected from the group consisting of at least one solvent selected from LiCl and CaCl ₂ .
The method according to claim 1,
The molecular chain structure of the aramid polymer is a method for producing an aramid / graphene / carbon nanotube composite, characterized in that it has at least 85% or more of the structure selected from the group consisting of repeating units of the following structural formula.

The method according to claim 1,
The composition ratio of the carbon nanoparticles in which the graphene and carbon nanotubes are mixed is 0.01 to 50.0% by weight based on the total weight of the composite, and the weight ratio of graphene: carbon nanotubes constituting the mixed carbon nanoparticles is 0.001: 99.999 to 99.999 Method for producing an aramid / graphene / carbon nanotube composite, characterized in that consisting of: 0.001.
The method according to claim 1,
The graphene is graphene surface-modified with one or two or more compounds selected from the group consisting of alkyl groups, allyl groups, carboxyl groups, hydroxyl groups, amine groups, epoxy groups, urethane groups, and urea group compounds, wherein the carbon nanotubes are Aramid / graphene / characterized in that the SWCNT or MWCNT surface-modified with one or two or more compounds selected from the group consisting of alkyl, allyl, carboxyl, hydroxyl, amine, epoxy, urethane, and urea compounds Method for producing a carbon nanotube composite.
delete Aramid / graphene / carbon nanotube composites prepared by the method of claim 1, wherein the aramid / graphene / carbon nanotube composite, characterized in that included in the fiber, film or plastic products.

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