TWI386447B - Method for making carbon nanotube array composite - Google Patents

Description

Method for preparing nano carbon tube array composite material

The invention relates to a preparation method of a composite material, in particular to a preparation method of a carbon nanotube array composite material.

Since the discovery of Carbon Nanotube (CNT) (Iilima S., Nature, vol 354, p56 (1991)), it has immediately attracted great attention from the scientific community and industry. Nano carbon tubes have many excellent properties and can be used in many fields. The carbon nanotubes are seamless hollow tubes made of graphite sheets. Due to the quantum confinement of electrons in the carbon nanotubes, electrons can only move along the axial direction of the carbon nanotubes in the graphite sheets. Therefore, the carbon nanotubes exhibit unique electrical and thermal properties. The test results show that the average conductivity of the carbon nanotubes can reach 1000~2000S/m (Siemens/meter), and the thermal conductivity at room temperature can reach 6600W/mK (Watt/m. Kelvin). In addition, the carbon nanotubes also have excellent mechanical properties such as high strength and modulus.

Nano carbon tubes are considered to be ideal additives for composite materials due to their excellent mechanical and electrical properties. Nanocarbon tubes/polymer composites have become the hotspot of scientific research in the world since their first report (Ajayan PM, Stephan O., Colliex C., Tranth D., Science., vol 265, p1212 (1994): Calvert P., Nature, vol 399, p210 (1999)). As a reinforcement and an electrical conductor, the carbon nanotubes have antistatic properties, absorption of microwaves and electromagnetic shielding, and have broad application prospects.

The preparation method of the carbon nanotube composite material usually has an in situ polymerization method and a solution. Blending and melt blending. The in-situ polymerization method utilizes a functional group on the surface of the carbon nanotube to participate in polymerization or an initiator to open the π bond of the carbon nanotube to participate in the polymerization reaction to achieve good compatibility with the organic phase. Solution blending generally involves dispersing a carbon nanotube into a solvent of a polymer, dissolving the polymer therein, and removing the solvent after processing to obtain a composite material. The melt blending method melts and uniformly mixes the carbon nanotubes and the polymer substrate material at a temperature greater than the melting point of the substrate material to obtain a carbon nanotube composite material.

Due to the excellent mechanical strength and thermal conductivity of the carbon nanotubes, the aligned carbon nanotube array structure can be used to prepare the carbon nanotube thermal conductive material and the carbon nanotube composite reinforcing material with excellent performance. The thermal conductivity and mechanical properties of the carbon nanotubes on the composite are related to the density of the carbon nanotubes in the composite.

Don N. Futaba et al. provide a method for preparing a carbon nanotube array composite (see "Shape-engineerable and highly densely packed single-walled carbon nanotubes and their application as super-capacitor electrodes", Don N. Futaba et al ., Nature Materials, vol 5, p987 (2000)). In this method, the surface-treated carbon nanotube array is directly immersed in a polymer solution, and the carbon nanotube array composite material is obtained after heat treatment. However, the preparation method of the above-mentioned carbon nanotube array composite material has the following disadvantages: First, the surface treatment of the carbon nanotube array is complicated, and the process is complicated. Second, the nanocarbon prepared by the above method is due to capillary action between the polymer material and the carbon nanotubes in the carbon nanotube array. tube In the array composite, the carbon nanotube array is deformed, which affects the overall performance of the carbon nanotube array composite, such as mechanical properties, electrical properties or thermal properties; third, due to the nano-carbon nanotube array The following impurity gases such as carbon dioxide, water vapor, etc. exist between the carbon tubes, so the electrical and thermal properties of the prepared carbon nanotube array composites are affected.

In view of the above, it is necessary to provide a method for preparing a carbon nanotube array composite which is simple in operation and which can maintain the original morphology of the carbon nanotube array in the composite material without generating impurities.

A method for preparing a carbon nanotube array composite material, comprising the steps of: providing a carbon nanotube array; fixing two ends of the carbon nanotube array along the extending direction of the carbon nanotubes on the two substrates; Providing a polymer precursor solution; infiltrating the nanocarbon tube array with the polymer precursor solution to form a polymer precursor solution/nanocarbon tube array mixture; and curing the polymer precursor solution/nano Carbon tube array hybrid.

Compared with the prior art, the preparation method of the carbon nanotube array composite provided by the technical solution has the following advantages: First, the preparation method does not require pretreatment of the carbon nanotube array, and the process is simple; Since the two ends of the carbon nanotube array in the extending direction of the carbon nanotubes are respectively fixed on the two substrates, the capillary action between the carbon nanotubes and the polymer solution does not cause deformation of the carbon nanotube array. The carbon nanotube array maintains the original appearance in the carbon nanotube array composite, improving the overall performance of the carbon nanotube array composite, such as mechanical properties, electrical properties or thermal properties. .

The invention will be further described in detail below with reference to the drawings and specific embodiments.

Referring to FIG. 1 and FIG. 2 , an embodiment of the present technical solution provides a method for preparing a carbon nanotube array composite material, which specifically includes the following steps:

Step 1. A carbon nanotube array 12 is provided.

In this embodiment, the carbon nanotube array 12 is formed on a substrate 14. The carbon nanotube array 12 includes a plurality of carbon nanotubes substantially perpendicular to the substrate 14. The carbon nanotube array 12 includes a first An end 122 and a second end 124 opposite the first end 122, the carbon nanotubes in the carbon nanotube array 12 extend from the second end 124 to the first end 122, and the second end 124 is disposed on the substrate 14. .

The specific preparation method of the carbon nanotube array 12 is not limited. The preparation method of the carbon nanotube array 12 in the embodiment of the technical solution adopts a chemical vapor deposition method, and the specific steps thereof include: (a) providing a flat substrate 14, The material of the substrate 14 may be selected from the group consisting of glass, ruthenium, ruthenium dioxide, metal or metal oxide. The embodiment of the technical solution preferably uses a ruthenium dioxide substrate; (b) uniformly forms a catalyst layer on the surface of the substrate 14, the catalyst layer The material may be one of iron (Fe), cobalt (Co), nickel (Ni) or any combination thereof; (c) the substrate 14 on which the catalyst layer is formed is annealed in air at 700 ° C - 900 ° C for about 30 Minutes-90 minutes; (d) The treated substrate 14 is placed in a reaction furnace, heated to 500 ° C - 740 ° C under a protective gas atmosphere, and then reacted with a carbon source gas for about 5 minutes to 30 minutes to grow. A carbon nanotube array 12 is obtained. The carbon nanotube array 12 is a plurality of carbon nanotube arrays 12 formed of carbon nanotubes that are parallel to each other and perpendicular to the substrate 14.

In the embodiment of the technical solution, the carbon source gas may be a chemically active hydrocarbon such as acetylene, ethylene or methane. The preferred carbon source gas in the embodiment of the technical solution is acetylene; the shielding gas is nitrogen or an inert gas, and the technical solution is The preferred shielding gas for the examples is argon.

It can be understood that the carbon nanotube array provided by the embodiments of the present technical solution is not limited to the above preparation method, and may be a graphite electrode constant current arc discharge deposition method, a laser evaporation deposition method, or the like.

Step 2: Fix the two ends of the carbon nanotube array 12 in the extending direction of the carbon nanotubes on the two substrates.

In this embodiment, the first end 122 and the second end 124 of the carbon nanotube array 12 are respectively fixed on a first substrate 16 and a second substrate 20, which specifically includes the following steps:

(1) A first substrate 16 and a second substrate 20 are provided.

The shapes of the first substrate 16 and the second substrate 20 are not limited, and include square, circular, triangular or other shapes, which have a flat surface. The materials of the first substrate 16 and the second substrate 20 are not limited, and may be selected from glass, cerium oxide, metal or metal oxide. In this embodiment, the first substrate 16 and the second substrate 20 are rectangular glass plates of equal size.

(2) Applying an adhesive to the surfaces of the first substrate 16 and the second substrate 20, respectively, to form a first adhesive layer 18 and a second adhesive layer 22.

The material of the binder of the adhesive layer is not limited and may be rubber, polyurethane glue or silicone rubber. The specific thickness of the adhesive layer is not limited, and may be determined according to actual conditions. Preferably, the thickness of the first adhesive layer 18 is from 1 micrometer to 10 micrometers, and the area of the adhesive layer is greater than or equal to the carbon nanotube. The area of the array 12. In this embodiment, a first adhesive layer 18 and a second adhesive layer 22, a first adhesive layer 18 and a second adhesive are respectively applied on the first substrate 16 and the second substrate 20. The agent layer 22 is made of silicone rubber and has a thickness of 5 micrometers.

(3) The first end 122 of the carbon nanotube array 12 is fixed to the first substrate 16 by the first adhesive layer 18.

After the first end 122 of the carbon nanotube array 12 is slowly brought into contact with the first adhesive layer 18, the first adhesive layer 18 is heated and dried at a certain temperature to cause the first end 122 of the carbon nanotube array 12 to be 122. It is firmly bonded to the first substrate 16. The temperature at which the first binder layer 18 is heated is related to the curing temperature of the binder material, and may be from 20 ° C to 150 ° C. In this embodiment, the binder is silicone, which is dried at 100 °C.

(4) The second end 124 of the carbon nanotube array 12 is fixed to the second substrate 20 through the second adhesive layer 22.

Since the carbon nanotube array 12 is formed on the substrate 14 in this embodiment, a step of removing the substrate 14 of the carbon nanotube array 12 is further included before the second end 124 is fixed to the second substrate 20. The method of removing the substrate 14 of the carbon nanotube array 12 may be selected by mechanical grinding, chemical etching or direct stripping. In this embodiment, the substrate 14 of the carbon nanotube array 12 is removed by direct stripping. It specifically includes the following steps: First, the substrate 14 of the carbon nanotube array 12 is fixed. The base of the carbon nanotube array 12 can be secured by tape, adhesive or clips or the like.

The carbon nanotube array 12 is then shoveled from the substrate 14 using a metal sheet. The metal sheet is brought into contact with the second end 124 of the carbon nanotube array 12, and the metal sheet is slowly moved into between the second end 124 of the carbon nanotube array 12 and the substrate 14, thereby arranging the carbon nanotube array 12 Shovel from the base 14. The material of the metal sheet is not limited and may be an alloy of copper, aluminum or iron and any combination thereof. The thickness of the metal sheet is not limited and may be determined according to actual conditions. Preferably, the thickness of the metal sheet is 5 micrometers to 15 micrometers.

After the substrate 14 of the carbon nanotube array 12 is removed, the second end 124 of the carbon nanotube array 12 is brought into contact with the second adhesive layer 22 on the second substrate 20, and is slowly contacted with the second adhesive layer 22. Thereafter, the second adhesive layer 22 is heated at a certain temperature to bond the second end 124 of the carbon nanotube array 12 to the second substrate 20.

It can be understood that the substrate 14 can also be left in contact with the second adhesive layer 22 on the second substrate 20, so that the second end 124 of the carbon nanotube array 12 is fixed to the second substrate 20 through the substrate 14. . Alternatively, the substrate 14 may be retained such that the substrate 14 is used directly as the second substrate 20 without the need for a second adhesive layer 22.

Optionally, after the first end 122 and the second end 124 of the carbon nanotube array 12 are respectively fixed on the first substrate 16 and the second substrate 20, the first substrate 16 and the second substrate 20 are further encapsulated. The step of forming a mold. The method of encapsulating the first substrate 16 and the second substrate 20 is to adhere three plate-shaped materials to the first substrate 16 and the second substrate 20 by a sealant. On one side, a mold can be formed after the sealant is solidified. The plate material may be the same material as the first substrate 16 or the second substrate 20 or a different material. The sealant may be a 706B type ruthenium sulfide rubber. The top of the mold has an opening. The carbon nanotube array 12 is located within the mold cavity of the mold, and the first substrate 16 and the second substrate 20 form two opposing side walls of the mold.

Step 3. Providing a polymer precursor solution.

The polymer precursor solution is a low viscosity liquid with a viscosity of less than 1 Pa. In seconds, it may be a liquid polymer material itself, a liquid formed by melting a polymer material, a solution in which a polymer material is dissolved in a solvent, or a liquid in which a monomer of a polymer material is mixed with a catalyst. Wherein, the polymer material is a thermosetting material or a thermoplastic material. The thermosetting material is an epoxy resin, a bismaleimide resin, a cyanate resin or a ruthenium rubber. The thermoplastic material is polypropylene, polyethylene, polyvinyl alcohol or polymethacrylate resin. The solvent for dissolving the polymer material is acetone, tetrahydrofuran, chloroform or ethyl acetate. It is to be understood that the polymer material according to the present invention is not limited to the above-described polymer material, and may be any liquid material which is a low viscosity liquid and which can be dissolved and melted to form a low viscosity liquid.

The polymer precursor solution used in the present embodiment is an epoxy resin solution. The epoxy resin solution is a solution of an epoxy resin in which an epoxy resin is dissolved in ethyl acetate.

Step 4: impregnating the carbon nanotube array 12 with the polymer precursor solution to form a polymer precursor/carbon nanotube array mixture.

In this embodiment, the polymer precursor solution is slowly injected into the cavity along the inner wall of the mold, so that the polymer precursor solution does not pass through the carbon nanotube array 12. The rate of injecting the polymer precursor solution is not too fast, so as to prevent the polymer precursor solution from destroying the carbon nanotube array 12, and at the same time, the liquid surface of the polymer precursor solution in the mold exceeds the carbon nanotube array 12, so that The polymer precursor solution completely infiltrate the carbon nanotube array 12. After the polymer precursor solution is injected into the mold, the carbon nanotube array 12 and the polymer precursor solution form a polymer precursor/nanocarbon tube array mixture.

It can be understood that the carbon nanotube array 12 fixed on the two substrates respectively can be directly immersed in the polymer precursor solution to form a polymer precursor/carbon nanotube array mixture.

In the above process, in order to prevent the solid precursor solution solution from solidifying or increasing the viscosity, the viscosity of the polymer precursor solution is maintained at less than 1 Pa. In seconds, the temperature of the polymer precursor solution can be maintained at 20 ° C - 80 ° C. In this embodiment, the temperature of the solution of the epoxy resin was maintained at 60 °C.

Step 5: curing the polymer precursor solution in the polymer precursor solution/carbon nanotube array mixture to form a carbon nanotube array composite.

Before curing the polymer precursor solution in the polymer precursor solution/carbon nanotube array mixture, further comprising a method of vacuum processing a pair of the polymer precursor/carbon nanotube array mixture, including The following steps: placing the molecular precursor/carbon nanotube array mixture in a closed vacuum chamber; evacuating the vacuum chamber by using an air extracting device, and having a polymer precursor/carbon nanotube array mixture Bubble discharge; when polymer When the discharge of the bubble is stopped in the precursor/carbon nanotube array mixture, the evacuation is stopped, and the vacuum is maintained for a while.

In this process, as the degree of vacuum in the vacuum chamber increases, the pressure at the liquid level of the polymer precursor solution decreases, and the bubbles present in the polymer precursor/carbon nanotube array mixture are discharged. When the vacuum in the vacuum chamber reaches 10 _-4 Pa - 10 ^-6 Pa, the polymer precursor/carbon nanotube array mixture no longer continues to have bubble discharge, at which time the vacuum is stopped and the vacuum is maintained for 10 minutes - 30 minutes.

In this embodiment, when the degree of vacuum reaches 10 ^-5 Pa, the polymer precursor/carbon nanotube array mixture no longer continues to have bubble discharge, at which time the evacuation is stopped and the vacuum is maintained for 20 minutes.

The vacuum-treated polymer precursor/carbon nanotube array mixture is placed in a heating furnace together with a mold, and heated at a temperature of 80 ° C to 100 ° C for 1 hour to 30 hours, and then at a temperature of 120 ° C to 300 ° C. After heating for 3 hours to 20 hours, the polymer precursor solution is solidified, and after cooling to room temperature, a carbon nanotube array composite material is obtained.

It can be understood that the temperature of the cured polymer precursor/carbon nanotube array mixture is related to the composition of the polymer precursor solution and the curing temperature of the polymer material, and is not limited to the above temperature range.

In this embodiment, after the carbon nanotube array composite material is quenched along the extending direction of the carbon nanotube tube, the cross section is observed by scanning electron microscopy, and its morphology is shown in FIG. As can be seen from Figure 3, the carbon nanotube array maintains a good array morphology in the carbon nanotube array composite.

Preparation method of carbon nanotube array composite material provided by the technical solution There are the following advantages: First, the preparation method does not require pretreatment of the carbon nanotube array, and the process is simple; and second, since both ends of the carbon nanotube array in the extending direction of the carbon nanotube are respectively fixed to the two substrates Above, the capillary action between the carbon nanotube and the polymer solution does not cause deformation of the carbon nanotube array, and the carbon nanotube array maintains the original appearance in the carbon nanotube array composite, and the carbon nanotube is improved. The overall performance of the array composite, such as mechanical properties, electrical properties or thermal properties; third, vacuuming the carbon nanotube array to eliminate impurities such as water vapor and carbon dioxide in the carbon nanotube array.

In summary, the present invention has indeed met the requirements of the invention patent, and has filed a patent application according to law. However, the above description is only a preferred embodiment of the present invention, and it is not possible to limit the scope of the patent application of the present invention. Equivalent modifications or variations made by persons skilled in the art in light of the spirit of the invention are intended to be included within the scope of the following claims.

12‧‧‧Nano Carbon Tube Array

122‧‧‧ the first end of the carbon nanotube array

124‧‧‧Second end of carbon nanotube array

14‧‧‧Base

16‧‧‧First substrate

18‧‧‧First adhesive layer

20‧‧‧second substrate

22‧‧‧Second binder layer

FIG. 1 is a flow chart of a method for preparing a carbon nanotube array composite material provided by an embodiment of the present technical solution.

FIG. 2 is a schematic diagram of a preparation process of a carbon nanotube array composite material provided by an embodiment of the present technical solution.

3 is a scanning electron micrograph of a cross section of a carbon nanotube array composite provided by an embodiment of the present technical solution.

Claims (14)

A method for preparing a carbon nanotube array composite material, comprising the steps of: providing a carbon nanotube array; respectively fixing the carbon nanotube array on both ends of the carbon nanotube extending direction on the two substrates; assembling the The two substrates form a mold, the mold has an opening; a polymer precursor solution is provided; and the polymer precursor solution is added to the mold from the opening of the mold along the sidewall of the mold to infiltrate the nanocarbon The tube array forms a polymer precursor/nanocarbon nanotube array mixture; and a cured polymer precursor/nanocarbon tube array hybrid. The method for preparing a carbon nanotube array composite according to claim 1, wherein the carbon nanotube array is formed on a substrate, and the carbon nanotube array has a first end and a first The second end of the opposite end is connected to the substrate. The method for preparing a carbon nanotube array composite according to claim 2, wherein the method of fixing the carbon nanotube array to the two substrates at both ends of the carbon nanotube extending direction includes the following Step: providing a first substrate and a second substrate; respectively applying an adhesive on the surfaces of the first substrate and the second substrate to form a first adhesive layer and a second adhesive layer; The first end of the carbon tube array is fixed on the first substrate by the first adhesive layer; the second end of the carbon nanotube array is fixed on the second substrate by the second adhesive layer. The manufacture of a carbon nanotube array composite material as described in claim 3 The method for fixing the second end of the carbon nanotube array to the second substrate through the second adhesive layer is to bond the substrate of the carbon nanotube array to the second substrate on the second substrate. The layer of the layer is contacted such that the second end of the array of carbon nanotubes is fixed to the second substrate through the substrate. The method for preparing a carbon nanotube array composite according to claim 3, wherein the method of fixing the second end of the carbon nanotube array to the second substrate by an adhesive comprises the following steps : removing the substrate by mechanical grinding, chemical etching or direct stripping; contacting the second end of the carbon nanotube array with the second adhesive layer on the second substrate to make the second end of the carbon nanotube array Fixed on the second substrate. The method for preparing a carbon nanotube array composite according to claim 5, wherein the method for directly removing the substrate comprises the steps of: fixing a substrate of the carbon nanotube array; A sheet of metal shovel the array of carbon nanotubes from the substrate. The method for preparing a carbon nanotube array composite according to claim 6, wherein the metal sheet has a thickness of 5 μm to 15 μm. The method for preparing a carbon nanotube array composite according to claim 3, wherein after the carbon nanotube array is fixed on both substrates in the extending direction of the carbon nanotube, the The two substrate packages form a mold. The method for preparing a carbon nanotube array composite according to the first aspect of the invention, wherein the polymer precursor solution is a liquid polymer material, a liquid formed by melting a polymer material, and a polymer material is dissolved. A liquid formed by mixing a solution of a solution or a polymer material formed in a solvent with a catalyst. The manufacture of a carbon nanotube array composite material as described in claim 9 The preparation method, wherein the polymer material precursor solution has a viscosity of less than 1 Pa. second. The method for preparing a carbon nanotube array composite according to claim 9, wherein the polymer material is a thermosetting material or a thermoplastic material. The method for preparing a carbon nanotube array composite according to claim 1, wherein the solid polymer precursor/carbon nanotube array mixture further comprises a pair of polymer precursors/nai The step of vacuum processing of the carbon nanotube array mixture. The method for preparing a carbon nanotube array composite according to claim 12, wherein the method for vacuum processing the polymer precursor/carbon nanotube array mixture comprises the following steps: The precursor/nanocarbon nanotube array mixture is placed in a closed vacuum chamber; the vacuum chamber is evacuated, and a bubble is discharged from the polymer precursor/carbon nanotube array mixture; when the polymer precursor/nano When the discharge of the bubbles in the carbon tube array mixture is stopped, the evacuation is stopped, and the vacuum is maintained at 10 ^-4 Pa - 10 ^-6 Pa for 10 minutes - 30 minutes. The method for preparing a carbon nanotube array composite according to claim 12, wherein the method for curing the polymer precursor/carbon nanotube array mixture comprises the following steps: vacuum treatment The polymer precursor/carbon nanotube array mixture is heated at a temperature of 80 ° C to 100 ° C for 1 hour to 30 hours; after heating at 120 ° C to 300 ° C for 3 hours to 20 hours; and cooled to room temperature.