CN111217586B - Ultra-light graphene/multi-walled carbon nanotube composite wave-absorbing foam and preparation method thereof - Google Patents

Ultra-light graphene/multi-walled carbon nanotube composite wave-absorbing foam and preparation method thereof Download PDF

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CN111217586B
CN111217586B CN202010035302.8A CN202010035302A CN111217586B CN 111217586 B CN111217586 B CN 111217586B CN 202010035302 A CN202010035302 A CN 202010035302A CN 111217586 B CN111217586 B CN 111217586B
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walled carbon
carbon nanotube
graphene
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absorbing foam
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CN111217586A (en
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杜作娟
张乾诚
黄小忠
陈爱良
侯明明
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Central South University
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Abstract

The invention discloses ultralight graphene/multi-walled carbon nanotube composite wave-absorbing foam and a preparation method thereof. Ultrasonically dispersing raw materials such as graphene oxide and carboxylated multi-walled carbon nanotubes into water, adding an alcohol solvent, uniformly stirring, standing in a vacuum environment, sequentially performing oriented freezing, freeze drying and thermal reduction to obtain the graphene/multi-walled carbon nanotube composite wave-absorbing foam, wherein the composite wave-absorbing foam has an oriented pore diameter structure, the shape and the internal average inner diameter of the composite wave-absorbing foam are controllable, and the density is as low as 0.002-1.2 g/cm3The graphene/multi-walled carbon nanotube composite wave-absorbing foam has an electromagnetic wave absorption effect at 2-40 GHz, has excellent wave-absorbing properties lower than-8 dB, -10dB and-17 dB at the frequency bands of X, Ku and Ka, and can be further compounded with a plastic high polymer material to improve the mechanical properties. The preparation process of the composite foam is simple, the cost is low, and the composite foam can be produced in a large scale.

Description

Ultra-light graphene/multi-walled carbon nanotube composite wave-absorbing foam and preparation method thereof
Technical Field
The invention relates to a foam wave-absorbing material, in particular to an ultralight graphene/multi-walled carbon nanotube composite wave-absorbing foam material which is ultralight, has an oriented pore diameter structure and has a wider effective absorption bandwidth, and also relates to a method for preparing ultralight graphene/multi-walled carbon nanotube composite wave-absorbing foam by utilizing an oriented freezing and freeze-drying technology, belonging to the technical field of wave-absorbing materials.
Background
The communication technology of rapid iteration is closely combined with artificial intelligence and big data, and the communication between people and equipment is changed to the interconnection of everything. However, with the rapid development and the gradually widespread application of modern communication technologies such as 5G mobile communication technology, radar system, RFID radio frequency payment, etc., the number of miniaturized and lightweight electromagnetic wave wireless communication devices is increasing, and the accompanying electromagnetic wave pollution and signal interference between electronic devices become a great threat to wearable devices and portable electronic product communication modules, so there is a great application demand for novel lightweight high-performance electromagnetic wave absorbing materials.
Different from high-density and easily-corroded metal-based wave-absorbing materials, such as oxides and sulfides of iron, manganese, titanium, zinc, silicon and aluminum, and alloys and metal organic frameworks thereof, inorganic non-metal materials mainly comprise carbon-based and carbonitride, and due to the characteristics of good dielectric property, light weight, stable chemical property and the like, the inorganic non-metal materials are widely researched in recent years. The graphene serving as a typical two-dimensional material with good electron mobility, specific surface area, thermal stability and mechanical property is not only applied to the aspects of transistors, super capacitors, energy storage and gas sensors, but also serves as a new wave-absorbing material to be used for preparing various wave-absorbing composite materials.
In the wave-absorbing application of graphene, the graphene is compounded with magnetic metal, transition metal, oxide and sulfide thereof, such as gamma-Fe2O3、Fe3O4/rGO、NiO/rGO、Co3O4/rGO、MnFe2O4/rGO、CoFe2O4:SnS/rGO、MoS2/rGO, etc. The composition of the metal oxide and the sulfide can improve the defect of electromagnetic matching of pure graphene, so that the composite material can generate a strong absorption peak in a small thickness. However, the composite material can only be dispersed in other matrixes such as paraffin, rubber and resin as a filler, so that the density of the composite material is increased, and the original light weight characteristic of graphene is lost. And the wave absorbing characteristics of the composite material are mostly represented by one or two strong absorption peaks with narrow effective bandwidth in target frequency, so that the application of the composite material is limited. For example: chinese patents CN110079271A and CN110012656A disclose wave-absorbing materials modified by carbon materials or magnetic metals thereof, respectively, but the wave-absorbing materials are modified by carbon materials or magnetic metals thereofThe carbon source is only used as a filler, and a corresponding supporting matrix needs to be doped, and the absorption peak is narrow, so that the application requirement is difficult to meet. The other wave-absorbing material is prepared from graphene or graphene composite aerogel. The aerogel is mostly prepared by a hydrothermal method or a solvothermal method, can be self-supported, has high porosity and can meet the application of the light-weight high-performance wave-absorbing material. However, the process of preparing the aerogel by the hydrothermal method is relatively complex, the volume of the aerogel is limited by the size of the container, the shrinkage of the aerogel relative to the container is severe, the shape is difficult to control, and further processing is required if the aerogel is applied. For example: chinese patents CN110272719A and CN109573988A disclose several carbon-based composite aerogel materials respectively, but the shapes of the carbon-based composite aerogel materials cannot be controlled manually.
Disclosure of Invention
Aiming at the defects of graphene and composite wave-absorbing materials thereof in the prior art, the invention aims to provide the graphene/multi-walled carbon nanotube composite wave-absorbing foam which has a directional aperture structure, is controllable in shape, is ultralight, has certain mechanical strength, has an electromagnetic wave absorption effect at 2-40 GHz, and has excellent wave-absorbing performance lower than-8 dB, -10dB and-17 dB at X, Ku and Ka frequency bands.
The second purpose of the invention is to provide a method for preparing the graphene/multi-walled carbon nanotube composite wave-absorbing foam, which has the advantages of simple process flow and low cost.
In order to achieve the technical purpose, the invention provides a preparation method of ultralight graphene/multi-walled carbon nanotube composite wave-absorbing foam, which comprises the following steps:
1) ultrasonically dispersing raw materials including graphene oxide and carboxylated multi-walled carbon nanotubes into water, adding an alcohol solvent, uniformly stirring to obtain a mixed solution, and standing the mixed solution in a vacuum environment to obtain a graphene oxide/carboxylated multi-walled carbon nanotube suspension;
2) sequentially carrying out oriented freezing and freeze drying treatment on the graphene oxide/carboxylated multi-walled carbon nanotube suspension to obtain graphene oxide/carboxylated multi-walled carbon nanotube foam;
3) carrying out thermal reduction treatment on the graphene oxide/carboxylated multi-walled carbon nanotube foam to obtain the graphene/multi-walled carbon nanotube composite wave-absorbing foam, or compounding the graphene/multi-walled carbon nanotube composite wave-absorbing foam with a plastic macromolecule to obtain the polymer-based graphene/multi-walled carbon nanotube composite wave-absorbing foam.
In a preferable scheme, the mass ratio of the graphene oxide to the carboxylated multi-walled carbon nanotube is 20: 1-1: 20. The graphene oxide carboxylated multi-walled carbon nanotube is a conventional commercial product.
In a preferable scheme, the concentration of the graphene oxide and the concentration of the carboxylated multi-wall carbon nano-tube in water are both lower than 20 mg/mL. If the concentration of the graphene oxide and the carboxylated multi-walled carbon nanotube is too high, the stable dispersion is difficult, and the graphene oxide and the carboxylated multi-walled carbon nanotube are easy to agglomerate and precipitate after standing.
In a preferred scheme, the raw material further comprises at least one of lignin, cellulose, chitin and chitosan. The lignin, cellulose, chitin and chitosan are introduced into the raw materials, so that the influence on the wave absorbing performance of the graphene/multi-walled carbon nanotube composite wave absorbing foam is small, but the mechanical property of the composite foam can be improved. And after high-temperature thermal reduction, lignin, chitosan and the like can form amorphous carbon on the walls of the directional pore structure, and the amorphous carbon can play a role in supporting foam.
In a preferred scheme, the concentrations of the lignin, the cellulose, the chitin and the chitosan in water are all lower than 30 mg/mL.
In a preferred scheme, the alcohol solvent comprises at least one of methanol, ethanol, benzyl alcohol and ethylene glycol;
in a preferable scheme, the volume ratio of the alcohol solvent to water is 1: 60-1: 5. On one hand, the alcohol solvent is used as a pore size regulator, the pore size of the graphene/multi-walled carbon nanotube composite wave-absorbing foam can be regulated according to the dosage proportion, on the other hand, the surface tension and the freezing point of water can be reduced, and if the alcohol solvent is not added, the foam is easy to crack.
Preferably, the orientation freezing is realized by an orientation freezing device; the orientation freezing device comprises a piece of high heat conduction metal and an open container; the bottom or the side wall of the open container is in contact with the high heat-conducting metal block. The shape of the high thermal conductivity metal is not limited, but preferably has a regular shape to have a good contact surface with the open container, such as a rectangular parallelepiped shape. The open container can be open, the cross section is a square or round concave body, and the specific shape can be designed according to the shape of the required ultralight graphene/multi-walled carbon nanotube composite wave-absorbing foam. The bottom or the side wall of the open container is in contact with the high-heat-conductivity metal to obtain the ultralight graphene/multi-walled carbon nanotube composite wave-absorbing foam with different oriented pore structures, for example, the bottom of the open container is in contact with the high-heat-conductivity metal block to obtain a pore structure with Z-axis orientation, and the side wall of the open container is in contact with the high-heat-conductivity metal block to obtain a pore structure with X-axis or Y-axis orientation.
Preferably, the orientation freezing treatment process comprises the following steps: freezing the high-thermal-conductivity metal block to the temperature below-20 ℃, contacting the metal block with an open container, and pouring the graphene oxide/carboxylated multi-walled carbon nanotube suspension into the open container until the suspension is cooled and solidified.
Preferably, the heat conductivity coefficient of the high heat conductivity metal is more than 200W/mK. Such as aluminum, gold, copper, silver, 1070 type aluminum alloy, 6063 type aluminum alloy, H96 copper zinc alloy, gold and silver alloy, etc.
Preferably, the open container is made of metal, polymer or inorganic non-metal material. Such as stainless steel, epoxy, silicone rubber, quartz, glass, etc.
Preferably, the freeze drying condition is drying for 24-96 h in an environment with the temperature below-20 ℃ and the vacuum degree below 0.1 Pa.
Preferably, the thermal reduction treatment process is as follows: and (3) carrying out heat treatment at the temperature of 200-1050 ℃ in a protective atmosphere. The preferable temperature is 400-800 ℃. Protective atmospheres such as nitrogen, argon, and the like.
In a preferable scheme, the time of ultrasonic treatment is 0.5-6 h. The ultrasonic power is 300-800W.
In a preferable scheme, the stirring time is 0.5-6 h.
In the preferable scheme, the mixed solution is placed in a vacuum environment of 0.02MPa to 0.09MPa for standing treatment for 5 to 30 min. Free bubbles in the suspension can be removed by vacuum standing treatment.
Preferably, the plastic polymer refers to an organic polymer material having plasticity, such as rubber, plastic, and resin, for example, silicone rubber, TPU, epoxy resin, and PDMS. The process of compounding the polymer materials and the graphene/multi-walled carbon nanotube composite wave-absorbing foam can adopt in-situ curing and other ways for compounding.
The invention also provides the ultralight graphene/multi-walled carbon nanotube composite wave-absorbing foam which is prepared by the preparation method.
The ultralight graphene/multi-walled carbon nanotube composite wave-absorbing foam has an oriented pore diameter structure, the shape of the composite foam and the size of the average inner diameter of the composite foam are controllable, and the density is as low as 2-10 mg/cm3The composite material has an electromagnetic wave absorption effect at 2-40 GHz, and has excellent wave absorption performance lower than-8 dB, -10dB and-17 dB at X, Ku and Ka frequency bands.
Compared with the prior art, the technical scheme of the invention has the advantages that:
1) the density of the graphene/multi-walled carbon nanotube composite wave-absorbing foam is 2-10 mg/cm3Lower than other graphene foams or aerogels.
2) The graphene/multi-walled carbon nanotube composite wave-absorbing foam has a controllable shape, has a certain mechanical property, can be self-supported, and can be filled with TPU or resin materials according to needs to further improve the mechanical property.
3) The aperture size of the graphene/multi-walled carbon nanotube composite wave-absorbing foam can be regulated and controlled according to the content of absolute ethyl alcohol.
4) The graphene/multi-walled carbon nanotube composite wave-absorbing foam has an electromagnetic wave absorption effect at 2-40 GHz, and has excellent wave-absorbing properties lower than-8 dB, -10dB and-17 dB at X, Ku and Ka frequency bands.
5) The preparation method of the graphene/multi-walled carbon nanotube composite wave-absorbing foam has the characteristics of short process flow, low cost and the like, does not need to use complex directional freezing equipment and liquid nitrogen in the directional freezing process, and can realize the preparation of the wave-absorbing foam with the directional aperture structure only by adopting metal or alloy blocks and corresponding containers (molds).
Drawings
FIG. 1 is an exemplary diagram of an orientation freezing process;
FIG. 2 is an SEM electron micrograph of a graphene/multiwalled carbon nanotube composite foam structure;
FIG. 3 is a 26.5-40 GHz radar reflectivity curve of the graphene/multiwalled carbon nanotube composite wave-absorbing foam prepared in example 1;
FIG. 4 is a 26.5-40 GHz radar reflectivity curve of the graphene/multiwalled carbon nanotube composite wave-absorbing foam prepared in example 2;
FIG. 5 is a 26.5-40 GHz radar reflectivity curve of the graphene/multiwalled carbon nanotube composite wave-absorbing foam prepared in example 3;
FIG. 6 is a radar reflectivity curve of 8-18 GHz of the graphene/multiwalled carbon nanotube composite wave-absorbing foam prepared in example 3;
FIG. 7 is a 26.5-40 GHz radar reflectivity curve of the graphene/multiwalled carbon nanotube/amorphous carbon composite wave-absorbing foam prepared in example 4;
fig. 8 is a comparison of compressive mechanical properties of the graphene composite foams of examples 2, 4, and 5;
fig. 9 is a comparison of compression mechanical properties of graphene composite foams of examples 6 and 7 after filling epoxy resin or TPU.
Detailed Description
The following examples are intended to further illustrate the present disclosure, but not to limit the scope of the claims.
Example 1
1) And (3) mixing 421mg of graphene oxide, 84.2mg of carboxylated multi-walled carbon nanotubes and 72.2mL of deionized water, carrying out 500W ultrasonic treatment for 30min, carrying out magnetic stirring for 1h, and adding 5.6mL of absolute ethyl alcohol after stirring.
2) Putting the suspension obtained in the step 1) into an environment with the vacuum degree of 0.04MPa, and standing for 10 min.
3) Placing the polished copper block with the length, width and height of 200 x 50mm into a low-temperature refrigerator for freezing until the temperature is-85 ℃, taking out the copper block to the environment with the room temperature of 20 ℃, placing a quartz dish with the inner diameter of 190 x 10mm and the wall thickness of 2mm and the four corners of which are chamfered to phi 1mm on the copper block, pouring the suspension liquid in the step 2) into the quartz dish, and waiting for about 6min until the suspension liquid is solidified.
4) And (3) putting the quartz capsule and the solidified suspension liquid in the step 3) into a freeze dryer, and freeze-drying for 48 hours at-60 ℃ under the environment of 0.1Pa to ensure that ice is completely sublimated, thereby obtaining the graphene oxide/carboxylated multi-walled carbon nanotube foam.
5) Putting the graphene oxide/carboxylated multi-walled carbon nanotube foam obtained in the step 4) into a box type furnace, and putting the foam in the N2Raising the temperature from room temperature to 500 ℃ at a speed of 5 ℃/min under protection, keeping the temperature at 500 ℃ for 1h, and cooling to room temperature to obtain the graphene/multi-walled carbon nanotube composite wave-absorbing foam.
The graphene/multi-walled carbon nanotube composite foam prepared in the embodiment is tested according to the example, the macroscopic size is 180 x 2mm, the average pore size in the foam is 50 μm, and the reflectivity is tested by a bow method to be 26.5-40 GHz, and the full frequency band is below-15 dB.
Example 2
1) And (3) mixing 421mg of graphene oxide, 84.2mg of carboxylated multi-walled carbon nanotubes and 72.2mL of deionized water, carrying out ultrasonic treatment at 500W for 30min, carrying out magnetic stirring for 1h, and adding 2.8mL of absolute ethyl alcohol after stirring.
2) Putting the suspension obtained in the step 1) into an environment with the vacuum degree of 0.04MPa, and standing for 10 min.
3) Placing the polished copper block with the length, width and height of 200 x 50mm into a low-temperature refrigerator for freezing until the temperature is-85 ℃, taking out the copper block to the environment with the room temperature of 20 ℃, placing a quartz dish with the inner diameter of 190 x 10mm and the wall thickness of 2mm and the four corners of which are chamfered to phi 1mm on the copper block, pouring the suspension liquid in the step 2) into the quartz dish, and waiting for about 6min until the suspension liquid is solidified.
4) And (3) putting the quartz capsule and the solidified suspension liquid in the step 3) into a freeze dryer, and freeze-drying for 48 hours at-60 ℃ under the environment of 0.1Pa to ensure that ice is completely sublimated, thereby obtaining the graphene oxide/carboxylated multi-walled carbon nanotube foam.
5) Will step withPutting the graphene oxide/carboxylated multi-walled carbon nanotube foam obtained in the step 4) into a box type furnace, and putting the foam in a reactor in the presence of N2Raising the temperature from room temperature to 800 ℃ at a speed of 5 ℃/min under protection, keeping the temperature at 800 ℃ for 1h, and cooling to room temperature to obtain the graphene/multi-walled carbon nanotube composite foam.
According to the test of the embodiment, the macroscopic size of the graphene/multi-walled carbon nanotube composite wave-absorbing foam is 180 x 2mm, the average pore diameter in the foam is 40 mu m, and the reflectivity tested by the bow method is below-10 dB in the full frequency band of 26.5-40 GHz.
Example 3
1) 842mg of graphene oxide, 168.4mg of carboxylated multi-walled carbon nanotubes and 144.4mL of deionized water are mixed, the mixture is subjected to 500W ultrasonic treatment for 30min, the mixture is magnetically stirred for 1h, and 5.6mL of absolute ethyl alcohol is added after the stirring is finished.
2) Putting the suspension obtained in the step 1) into an environment with the vacuum degree of 0.04MPa, and standing for 10 min.
3) Placing the polished copper block with the length, width and height of 200 x 50mm into a low-temperature refrigerator for freezing until the temperature is-85 ℃, taking out the copper block to the environment with the room temperature of 20 ℃, placing a quartz dish with the inner diameter of 190 x 10mm and the wall thickness of 2mm and the four corners of which are rounded off to phi 1mm on the copper block, pouring the suspension liquid in the step 2) into the quartz dish, and waiting for about 18min until the suspension liquid is solidified.
4) And (3) putting the quartz capsule and the solidified suspension liquid in the step 3) into a freeze dryer, and freeze-drying for 48 hours at-60 ℃ under the environment of 0.1Pa to ensure that ice is completely sublimated, thereby obtaining the graphene oxide/multi-wall carboxylated multi-wall carbon nanotube foam.
5) Putting the graphene oxide/carboxylated multi-walled carbon nanotube foam obtained in the step 4) into a box type furnace, and putting the foam in the N2Raising the temperature from room temperature to 400 ℃ at a speed of 5 ℃/min under protection, keeping the temperature at 400 ℃ for 1h, and cooling to room temperature to obtain the graphene/multi-walled carbon nanotube composite foam.
According to the test of the embodiment, the macroscopic size of the graphene/multi-walled carbon nanotube composite wave-absorbing foam is 180 x 4mm, the reflectivity tested by the bow method is below-8 dB at 8-18 GHz full-band reflectivity, and the 26.5-40 GHz full-band reflectivity is below-10 dB.
Example 4
1) Taking 421mg of graphene oxide, 84.2mg of carboxylated multi-walled carbon nanotubes and 140mg of alkaline lignin, mixing with 72.2mL of deionized water, carrying out ultrasonic treatment at 500W for 30min, magnetically stirring for 1h, and adding 2.8mL of absolute ethyl alcohol after stirring.
2) Putting the suspension obtained in the step 1) into an environment with the vacuum degree of 0.04MPa, and standing for 10 min.
3) Placing the polished copper block with the length, width and height of 200 x 50mm into a low-temperature refrigerator for freezing until the temperature is-85 ℃, taking out the copper block to the environment with the room temperature of 20 ℃, placing a quartz dish with the inner diameter of 190 x 10mm and the wall thickness of 2mm and the four corners of which are chamfered to phi 1mm on the copper block, pouring the suspension liquid in the step 2) into the quartz dish, and waiting for about 6min until the suspension liquid is solidified.
4) And (3) putting the quartz capsule and the solidified suspension liquid in the step 3) into a freeze dryer, and freeze-drying for 48 hours at-60 ℃ under the environment of 0.1Pa to ensure that ice is completely sublimated, thereby obtaining the graphene oxide/carboxylated multi-walled carbon nanotube foam.
5) Putting the graphene oxide/carboxylated multi-walled carbon nanotube foam obtained in the step 4) into a box type furnace, and putting the foam in the N2Raising the temperature from room temperature to 400 ℃ at a speed of 5 ℃/min under protection, keeping the temperature at 400 ℃ for 1h, cooling to room temperature to obtain the graphene/multi-wall carbon nanotube/amorphous carbon composite wave-absorbing foam, wherein the reflectivity tested by an arch method is below-10 dB in a full frequency band of 26.5-40 GHz.
Example 5
1) Taking 421mg of graphene oxide, 84.2mg of carboxylated multi-walled carbon nanotubes, 140mg of alkaline lignin, 70mg of chitosan, 1.5mL of glacial acetic acid and 72.2mL of deionized water, mixing the mixture with ultrasonic treatment at 500W for 30min, magnetically stirring the mixture for 1h, and adding 2.8mL of absolute ethyl alcohol after stirring.
2) Putting the suspension obtained in the step 1) into an environment with the vacuum degree of 0.04MPa, and standing for 10 min.
3) Placing the polished copper block with the length, width and height of 200 x 50mm into a low-temperature refrigerator for freezing until the temperature is-85 ℃, taking out the copper block to the environment with the room temperature of 20 ℃, placing a quartz dish with the inner diameter of 190 x 10mm and the wall thickness of 2mm and the four corners of which are chamfered to phi 1mm on the copper block, pouring the suspension liquid in the step 2) into the quartz dish, and waiting for about 6min until the suspension liquid is solidified.
4) And (3) putting the quartz capsule and the solidified suspension liquid in the step 3) into a freeze dryer, and freeze-drying for 48 hours at-60 ℃ under the environment of 0.1Pa to ensure that ice is completely sublimated, thereby obtaining the graphene oxide/carboxylated multi-walled carbon nanotube foam.
5) Putting the graphene oxide/carboxylated multi-walled carbon nanotube foam obtained in the step 4) into a box type furnace, and putting the foam in the N2Raising the temperature from room temperature to 400 ℃ at a speed of 5 ℃/min under protection, keeping the temperature at 400 ℃ for 1h, and cooling to room temperature to obtain the graphene/multi-walled carbon nanotube/amorphous carbon composite wave-absorbing foam.
Example 6
1) 72.2mL of epoxy hydrogel was poured into a 2mm thick rounded quartz dish with an inner diameter of 190X 10 mm.
2) The graphene composite foam prepared in example 1 was placed in a quartz dish and cured at room temperature for 24 hours.
Example 7
1) TPU 86.64g was dissolved in 75mL DMF and poured into an unburnt quartz dish with an inner diameter size of 190 x 10mm and a wall thickness of 2 mm.
2) The graphene composite foam prepared in example 1 was placed in a quartz dish and cured at room temperature for 48 hours.

Claims (8)

1. A preparation method of ultralight graphene/multi-walled carbon nanotube composite wave-absorbing foam is characterized by comprising the following steps: the method comprises the following steps:
1) ultrasonically dispersing raw materials including graphene oxide and carboxylated multi-walled carbon nanotubes into water, adding an alcohol solvent, uniformly stirring to obtain a mixed solution, and standing the mixed solution in a vacuum environment to obtain a graphene oxide/carboxylated multi-walled carbon nanotube suspension;
the raw materials also comprise at least one of lignin, cellulose, chitin and chitosan;
the concentrations of the lignin, the cellulose, the chitin and the chitosan in water are all lower than 30 mg/mL;
the alcohol solvent comprises at least one of methanol, ethanol, benzyl alcohol and glycol;
the volume ratio of the alcohol solvent to the water is 1: 60-1: 5;
2) sequentially carrying out oriented freezing and freeze drying treatment on the graphene oxide/carboxylated multi-walled carbon nanotube suspension to obtain graphene oxide/carboxylated multi-walled carbon nanotube foam;
3) carrying out thermal reduction treatment on the graphene oxide/carboxylated multi-walled carbon nanotube foam to obtain the graphene/multi-walled carbon nanotube composite wave-absorbing foam, or compounding the graphene/multi-walled carbon nanotube composite wave-absorbing foam with a plastic macromolecule to obtain the polymer-based graphene/multi-walled carbon nanotube composite wave-absorbing foam.
2. The preparation method of the ultralight graphene/multi-walled carbon nanotube composite wave-absorbing foam according to claim 1, characterized in that:
the mass ratio of the graphene oxide to the carboxylated multi-walled carbon nanotube is 20: 1-1: 20;
the concentrations of the graphene oxide and the carboxylated multi-wall carbon nano-tube in water are both lower than 20 mg/mL.
3. The preparation method of the ultralight graphene/multi-walled carbon nanotube composite wave-absorbing foam according to claim 1, characterized in that: the orientation freezing is realized by an orientation freezing device; the orientation freezing device comprises a piece of high heat conduction metal and an open container; the bottom or the side wall of the open container is in contact with the high heat-conducting metal block.
4. The preparation method of the ultralight graphene/multi-walled carbon nanotube composite wave-absorbing foam according to claim 1 or 3, characterized in that: the orientation freezing treatment process comprises the following steps: freezing the high-thermal-conductivity metal block to the temperature below-20 ℃, contacting the metal block with an open container, and pouring the graphene oxide/carboxylated multi-walled carbon nanotube suspension into the open container until the suspension is cooled and solidified.
5. The preparation method of the ultralight graphene/multi-walled carbon nanotube composite wave-absorbing foam according to claim 4, characterized in that:
the heat conductivity coefficient of the high heat conductivity metal is more than 200W/mK;
the open container is made of metal, high polymer or inorganic non-metal materials.
6. The preparation method of the ultralight graphene/multi-walled carbon nanotube composite wave-absorbing foam according to claim 1, characterized in that: the freeze drying condition is drying for 24-96 hours in an environment with the temperature below-20 ℃ and the vacuum degree below 0.1 Pa.
7. The preparation method of the ultralight graphene/multi-walled carbon nanotube composite wave-absorbing foam according to claim 1, characterized in that: the thermal reduction treatment process comprises the following steps: and (3) carrying out heat treatment at the temperature of 200-1050 ℃ in a protective atmosphere.
8. The ultra-light graphene/multi-walled carbon nanotube composite wave-absorbing foam is characterized in that: the preparation method of any one of claims 1 to 7.
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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104558701A (en) * 2015-01-21 2015-04-29 中国科学技术大学 Preparation method and application of laminated-structure graphene superelastic composite material
CN106904597A (en) * 2017-04-13 2017-06-30 合肥工业大学 It is a kind of being orientated the method that Freeze Drying Technique prepares CNT
CN108439389A (en) * 2018-04-11 2018-08-24 同济大学 A kind of preparation method of the carbon nano tube/graphene foam with Meta Materials performance
CN109810282A (en) * 2019-01-10 2019-05-28 东华大学 A kind of anisotropy polyimide aerogels material and preparation method thereof

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104558701A (en) * 2015-01-21 2015-04-29 中国科学技术大学 Preparation method and application of laminated-structure graphene superelastic composite material
CN106904597A (en) * 2017-04-13 2017-06-30 合肥工业大学 It is a kind of being orientated the method that Freeze Drying Technique prepares CNT
CN108439389A (en) * 2018-04-11 2018-08-24 同济大学 A kind of preparation method of the carbon nano tube/graphene foam with Meta Materials performance
CN109810282A (en) * 2019-01-10 2019-05-28 东华大学 A kind of anisotropy polyimide aerogels material and preparation method thereof

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