A preparation method of graphene / carbon nanotube / ferroferric oxide composite material for heat conduction and electromagnetic shielding

Abstract

The application relates to a preparation method of a graphene / carbon nanotube / ferroferric oxide composite material for heat conduction and electromagnetic shielding. The graphene / carbon nanotube / ferroferric oxide composite material is prepared through two steps of hydrothermal reaction and heat treatment. In the hydrothermal reaction process, ferroferric oxide particles are generated, and graphene oxide is wrapped on the surface of the ferroferric oxide particles; carboxylated carbon nanotubes are connected to the surface of the graphene oxide through group reaction; meanwhile, reduction reactions of the graphene oxide and the carboxylated carbon nanotubes occur, and a core-shell multi-level structure is formed. In the drying process, compression molding is carried out, and the graphene / carbon nanotube / ferroferric oxide composite material is obtained; the internal structure is that graphene sheets are stacked to wrap the ferroferric oxide particles, and the carbon nanotubes are cross-linked to form a carbon nanotube network; after high-temperature heat treatment, the dielectric constant of the composite material is greatly improved, a complete shielding network and a heat conduction path are formed, and excellent comprehensive performance is exhibited.

Description

Technical Field

[0001] This invention relates to a method for preparing a graphene / carbon nanotube / iron oxide composite material for thermal conductivity and electromagnetic shielding, belonging to the field of composite materials. Background Technology

[0002] With the rapid development of next-generation information technologies represented by 5G, the use of electromagnetic waves will permeate all aspects of people's production and life, meeting the advanced application needs of future industries such as the Internet of Things and virtual reality (VR). Furthermore, artificial intelligence, as a high-tech field capable of performing massive calculations, retrieval, and reasoning in a short time, can, with the support of 5G technology, perform detailed analysis of massive amounts of data, maximizing the powerful functions of AI. The combination of 5G and artificial intelligence has promoted the development of fields such as autonomous driving, intelligent manufacturing, and smart cities. However, with the increase in the power and integration of electronic devices, the overall power density of the system will inevitably increase significantly, causing related electronic components to generate a large amount of heat during operation. This leads to a rise in temperature, a sharp decline in performance, or even failure, affecting the working performance and lifespan of the equipment. [1] According to scientific statistics, for every 2°C increase in the internal temperature of electronic components, their reliability decreases by approximately 10%. [2] Therefore, heat dissipation has become a critical issue for high-power chips and other devices during operation. How to prevent overheating of devices and thus affect their lifespan and reliability has significant application value.

[0003] In addition to heat dissipation, electronic devices and components radiate a large amount of electromagnetic waves of different frequencies and wavelengths when they are working, which can lead to problems such as strong electromagnetic radiation, electromagnetic interference, and information leakage. [3] Compared to 4G, 5G networks use higher frequency bands, have wider bandwidth, and have more antennas at base stations. [4] High-speed, low-latency, and high-connectivity applications, along with the introduction of high frequencies, can lead to severe electromagnetic interference between and within devices. On one hand, electromagnetic waves can interfere with the normal operation of certain ultra-precise electronic instruments, endangering the information security of equipment such as computers; on the other hand, long-term electromagnetic radiation can cause serious harm to human health. [5] Therefore, how to avoid electromagnetic interference and reduce electromagnetic radiation intensity is another important issue that the entire industry cannot avoid. Currently, there are two main methods to solve electromagnetic interference and other problems: using shielding materials and absorbing materials. [6] Currently, researchers mostly use reflective electromagnetic shielding materials to block the propagation path of electromagnetic waves, achieving electromagnetic compatibility and protecting electronic components and equipment from electromagnetic radiation. [7] Developing composite materials that combine thermal conductivity and electromagnetic shielding is the most effective way to simultaneously solve the problems of efficient heat dissipation and electromagnetic compatibility in electronic devices.

[0004] References:

[0005] [1] LV P, TAN X-W, YU K-H, et al. Super-elastic graphene / carbon nanotube aerogel: A novel thermal interface material with highly thermal transport properties[J]. Carbon, 2016, 99: 222-228.

[0006] [2] ZHENG R, CHENG Y, JIANG X, et al. Fiber Templated Epitaxially Grown Composite Membranes: From Thermal Insulation to Infrared Stealth[J]. ACS Appl Mater Interfaces, 2022, 14. 27214-27221.

[0007] [3] LIANG L, LI Q, YAN X, et al. Multifunctional Magnetic Ti3C2T x MXene / Graphene Aerogel with Superior Electromagnetic Wave Absorption Performance[J]. ACS Nano, 2021, 15, 6622-6632.

[0008] [4] HUANG X, YU G, ZHANG Y, et al. Design of cellular structure of graphene aerogels for electromagnetic wave absorption[J]. Chemical Engineering Journal, 2021, 426, 131894.

[0009] [5]YANG J, YE Y, LI

[0010] [6] PAN F, RAO Y, BATALU D, et al. Macroscopic Electromagnetic Cooperative Network-Enhanced MXene / Ni Chains Aerogel-Based Microwave Absorber with UItra-Low Matching Thickness[J]. Nano-Micro Letters, 2022, 14, 140.

[0011] [7]ZHAO S, ZHANG HB, LUO JQ, et al.Highly Electrically ConductiveThree-Dimensional Ti3C2T x MXene / Reduced Graphene Oxide Hybrid Aerogels withExcellent Electromagnetic Interference Shielding Performances[J].ACS Nano, 2018, 12, 11193-11202. Summary of the Invention

[0012] The purpose of this invention is to provide a method for preparing a graphene / carbon nanotube / iron oxide composite material for thermal conductivity and electromagnetic shielding. During the hydrothermal reaction, iron oxide particles are generated, and graphene oxide is coated on the surface of the iron oxide particles. Carboxylated carbon nanotubes are attached to the surface of graphene oxide through group reaction. During the process, the reduction reaction of graphene oxide and carboxylated carbon nanotubes occurs simultaneously to form a core-shell multilevel structure.

[0013] The present invention adopts the following technical solution:

[0014] A method for preparing a graphene / carbon nanotube / ferric oxide composite material for thermal conductivity and electromagnetic shielding, comprising the following steps:

[0015] 1) Raw material preparation: Graphene oxide was synthesized using the Hummers method. A certain amount of concentrated sulfuric acid and phosphoric acid were uniformly mixed in a beaker, transferred to an ice bath, and then carbon nanotubes were added to the beaker. Potassium permanganate was used as an oxidant to functionalize the carbon nanotubes. Subsequently, a certain amount of graphene oxide, carboxylated carbon nanotubes, sodium citrate, urea, polyacrylamide, and ferric chloride hexahydrate were weighed out as raw materials for later use.

[0016] 2) Hydrothermal Reaction Process: The reagents weighed in step 1) are dissolved together with graphene oxide and carboxylated carbon nanotubes in a certain amount of deionized water. The mixed solution is homogenized by ultrasonication and vibration, then transferred to a tetrafluoroethylene-lined reactor. After placing the reactor in the reactor, it is placed in a muffle furnace for hydrothermal reaction at a certain temperature. During the hydrothermal reaction, iron oxide particles are generated, and graphene oxide coats the surface of the iron oxide particles. Carboxylated carbon nanotubes are attached to the surface of graphene oxide through group reactions. Simultaneously, reduction reactions of graphene oxide and carboxylated carbon nanotubes occur, forming a core-shell hierarchical structure. The reaction product is washed clean with ethanol and deionized water and prepared into a deionized water dispersion for later use.

[0017] 3) Hydrothermal reaction process: The aqueous dispersion prepared in step 2) is poured into a cylindrical mold and placed in an oven for preliminary drying. After a period of drying, most of the moisture has been removed, leaving a small amount of residue. At this point, a copper column is used to pressurize the solid components in the mold until it is completely dry. Finally, a composite material with graphene, carbon nanotubes, and iron oxide as the main components is obtained.

[0018] 4) Heat treatment process: The composite material obtained in step 3) is transferred to a vacuum tube furnace and heat-treated for a certain period of time in an atmosphere of argon and hydrogen, during which a reduction reaction occurs.

[0019] Preferably, in step 1), the mass of graphene oxide is 100-500 mg, the mass of carboxylated carbon nanotubes is 40-300 mg, the mass of sodium citrate is 5.6-14.4 mmol, the mass of urea is 6-48 mmol, the mass of polyacrylamide is 0.4-1.2 g, and the mass of ferric chloride hexahydrate is 0.8-1.2 g.

[0020] Preferably, in step 1), the volume ratio of concentrated sulfuric acid to phosphoric acid is 9:1.

[0021] Preferably, the volume of deionized water used for dissolution in step 2) is 40-80 ml.

[0022] Preferably, in step 2), the hydrothermal reaction temperature is set at 200–220°C, and the washing with ethanol and deionized water is performed 3–6 times each.

[0023] Preferably, the initial drying time in step 3) is 120-150 min.

[0024] Preferably, in step 4), the volume ratio of argon to hydrogen is 10:1, the final heat treatment temperature is 200–400°C, and the holding time is 30–60 min.

[0025] This invention prepares a graphene / carbon nanotube / ferric oxide composite material for thermal conductivity and electromagnetic shielding through two steps: hydrothermal reaction and heat treatment. During the hydrothermal reaction, ferric oxide particles are generated, with graphene oxide coating the surface of the particles. Carboxylated carbon nanotubes are attached to the graphene oxide surface via group reactions. Simultaneously, a reduction reaction occurs between the graphene oxide and the carboxylated carbon nanotubes, forming a core-shell hierarchical structure. The composite material is then pressed and shaped during drying to obtain the final product. Its internal structure consists of stacked graphene sheets encapsulating ferric oxide particles, with cross-connected carbon nanotubes forming a carbon nanotube network. Attached Figure Description

[0026] Figure 1 This is a physical image of a graphene / carbon nanotube / iron oxide composite material. Detailed Implementation

[0027] The following four embodiments of the present invention are provided to further illustrate the invention, but are not intended to limit the scope of the invention.

[0028] Example 1

[0029] 1) Raw material preparation: Graphene oxide was synthesized using the Hummers method. 45 ml of concentrated sulfuric acid and 5 ml of phosphoric acid were mixed evenly in a beaker, transferred to an ice bath, and then 2 g of carbon nanotubes were added to the beaker. Potassium permanganate was used as an oxidant to functionalize the carbon nanotubes. Subsequently, 100 mg of graphene oxide, 50 mg of carboxylated carbon nanotubes, 1.445 g of sodium citrate, 0.3604 g of urea, 0.4 g of polyacrylamide, and 1.084 g of ferric chloride hexahydrate were weighed out as raw materials for later use.

[0030] 2) Hydrothermal Reaction Process: The reagents weighed in step 1) are dissolved together with graphene oxide and carboxylated carbon nanotubes in 40 ml of deionized water. The mixture is homogenized by ultrasonication and vibration, then transferred to a tetrafluoroethylene-lined reactor. The reactor is then placed in a muffle furnace for hydrothermal reaction at 200°C. During the hydrothermal reaction, iron oxide particles are generated, and graphene oxide coats the surface of the iron oxide particles. Carboxylated carbon nanotubes are attached to the surface of graphene oxide through group reactions. Simultaneously, reduction reactions of graphene oxide and carboxylated carbon nanotubes occur, forming a core-shell hierarchical structure. The reaction product is washed three times each with ethanol and deionized water to prepare a deionized water dispersion for later use.

[0031] 3) Hydrothermal reaction process: The aqueous dispersion prepared in step 2) is poured into a cylindrical mold and placed in a 60℃ oven for preliminary drying. After drying for 120 minutes, most of the moisture has been removed, with only a small amount remaining. At this point, a copper column is used to pressurize the solid components in the mold until it is completely dry. Finally, a composite material with graphene, carbon nanotubes, and iron oxide as the main components is obtained.

[0032] 4) Heat treatment process: The composite material obtained in step 3) is transferred to a vacuum tube furnace and heat-treated at 200℃ for 30 min in an atmosphere with an argon to hydrogen volume ratio of 10:1. During the process, a further reduction reaction occurs.

[0033] Example 2

[0034] 1) Raw material preparation: Graphene oxide was synthesized using the Hummers method. 45 ml of concentrated sulfuric acid and 5 ml of phosphoric acid were mixed evenly in a beaker, transferred to an ice bath, and then 2 g of carbon nanotubes were added to the beaker. Potassium permanganate was used as an oxidant to functionalize the carbon nanotubes. Subsequently, 120 mg of graphene oxide, 72 mg of carboxylated carbon nanotubes, 1.445 g of sodium citrate, 2.883 g of urea, 0.8 g of polyacrylamide, and 0.9756 g of ferric chloride hexahydrate were weighed out as raw materials for later use.

[0035] 2) Hydrothermal Reaction Process: The reagents weighed in step 1) are dissolved together with graphene oxide and carboxylated carbon nanotubes in 40 ml of deionized water. The mixture is homogenized by ultrasonication and oscillation, then transferred to a tetrafluoroethylene-lined reactor. The reactor is placed in a muffle furnace and subjected to a hydrothermal reaction at 210°C. During the hydrothermal reaction, iron oxide particles are generated, and graphene oxide coats the surface of the iron oxide particles. Carboxylated carbon nanotubes are attached to the surface of graphene oxide through group reactions. Simultaneously, reduction reactions of graphene oxide and carboxylated carbon nanotubes occur, forming a core-shell hierarchical structure. The reaction product is washed four times each with ethanol and deionized water to prepare a deionized water dispersion for later use.

[0036] 3) Hydrothermal reaction process: The aqueous dispersion prepared in step 2) is poured into a cylindrical mold and placed in a 60℃ oven for preliminary drying. After drying for 120 minutes, most of the moisture has been removed, with only a small amount remaining. At this point, a copper column is used to pressurize the solid components in the mold until it is completely dry. Finally, a composite material with graphene, carbon nanotubes, and iron oxide as the main components is obtained.

[0037] 4) Heat treatment process: The composite material obtained in step 3) is transferred to a vacuum tube furnace and heat-treated at 300℃ for 40 min in an atmosphere with an argon to hydrogen volume ratio of 10:1. During the process, a further reduction reaction occurs.

[0038] Example 3

[0039] 1) Raw material preparation: Graphene oxide was synthesized using the Hummers method. 45 ml of concentrated sulfuric acid and 5 ml of phosphoric acid were mixed evenly in a beaker, transferred to an ice bath, and then 2 g of carbon nanotubes were added to the beaker. Potassium permanganate was used as an oxidant to functionalize the carbon nanotubes. Subsequently, 240 mg of graphene oxide, 120 mg of carboxylated carbon nanotubes, 2.89 g of sodium citrate, 2.883 g of urea, 0.6 g of polyacrylamide, and 1.1923 g of ferric chloride hexahydrate were weighed out as raw materials for later use.

[0040] 2) Hydrothermal Reaction Process: The reagents weighed in step 1) are dissolved together with graphene oxide and carboxylated carbon nanotubes in 60 ml of deionized water. The mixture is homogenized by ultrasonication and oscillation, then transferred to a tetrafluoroethylene-lined reactor. The reactor is placed in a muffle furnace and subjected to a hydrothermal reaction at 220°C. During the hydrothermal reaction, magnetite particles are generated, and graphene oxide coats the surface of the magnetite particles. Carboxylated carbon nanotubes are attached to the surface of graphene oxide through group reactions. Simultaneously, reduction reactions of graphene oxide and carboxylated carbon nanotubes occur, forming a core-shell hierarchical structure. The reaction product is washed four times each with ethanol and deionized water to prepare a deionized water dispersion for later use.

[0041] 3) Hydrothermal reaction process: The aqueous dispersion prepared in step 2) is poured into a cylindrical mold and placed in a 60℃ oven for preliminary drying. After drying for 140 minutes, most of the moisture has been removed, with only a small amount remaining. At this point, pressure is applied to the solid components in the mold through a copper column until it is completely dried. Finally, a composite material with graphene, carbon nanotubes, and iron oxide as the main components is obtained.

[0042] 4) Heat treatment process: The composite material obtained in step 3) is transferred to a vacuum tube furnace and heat-treated at 200℃ for 60 min in an atmosphere with an argon to hydrogen volume ratio of 10:1. During the process, a further reduction reaction occurs.

[0043] Example 4

[0044] 1) Raw material preparation: Graphene oxide was synthesized using the Hummers method. 45 ml of concentrated sulfuric acid and 5 ml of phosphoric acid were mixed evenly in a beaker, transferred to an ice bath, and then 2 g of carbon nanotubes were added to the beaker. Potassium permanganate was used as an oxidant to functionalize the carbon nanotubes. Subsequently, 250 mg of graphene oxide, 150 mg of carboxylated carbon nanotubes, 2.312 g of sodium citrate, 2.5947 g of urea, 0.8 g of polyacrylamide, and 1.084 g of ferric chloride hexahydrate were weighed out as raw materials for later use.

[0045] 2) Hydrothermal Reaction Process: The reagents weighed in step 1) are dissolved together with graphene oxide and carboxylated carbon nanotubes in 50 ml of deionized water. The mixture is homogenized by ultrasonication and vibration, then transferred to a tetrafluoroethylene-lined reactor. The reactor is then placed in a muffle furnace for hydrothermal reaction at 200°C. During the hydrothermal reaction, iron oxide particles are generated, and graphene oxide coats the surface of the iron oxide particles. Carboxylated carbon nanotubes are attached to the surface of graphene oxide through group reactions. Simultaneously, reduction reactions of graphene oxide and carboxylated carbon nanotubes occur, forming a core-shell hierarchical structure. The reaction product is washed four times each with ethanol and deionized water to prepare a deionized water dispersion for later use.

[0046] 3) Hydrothermal reaction process: The aqueous dispersion prepared in step 2) is poured into a cylindrical mold and placed in a 60℃ oven for preliminary drying. After drying for 130 minutes, most of the moisture has been removed, with only a small amount remaining. At this point, a copper column is used to pressurize the solid components in the mold until it is completely dry. Finally, a composite material with graphene, carbon nanotubes, and iron oxide as the main components is obtained.

[0047] 4) Heat treatment process: The composite material obtained in step 3) is transferred to a vacuum tube furnace and heat-treated at 300℃ for 60 min in an atmosphere with an argon to hydrogen volume ratio of 10:1. During the process, a reduction reaction occurs.

Claims

1. A method for preparing a graphene / carbon nanotube / ferric oxide composite material for thermal conductivity and electromagnetic shielding, characterized in that, Includes the following steps: 1) Raw material preparation: Graphene oxide is synthesized using the Hummers method. A certain amount of concentrated sulfuric acid and phosphoric acid are mixed evenly in a beaker, transferred to an ice bath, and carbon nanotubes are added to the beaker. Potassium permanganate is used as an oxidant to functionalize the carbon nanotubes. Then, a certain amount of graphene oxide, carboxylated carbon nanotubes, sodium citrate, urea, polyacrylamide, and ferric chloride hexahydrate are weighed out as raw materials for later use. 2) Hydrothermal reaction process: The drugs weighed in step 1) are dissolved together with graphene oxide and carboxylated carbon nanotubes in a certain amount of deionized water. The mixed solution is mixed evenly by ultrasound and vibration, and then transferred to the inner lining of a tetrafluoroethylene reactor. After placing the reactor in the reactor, the reactor is placed in a muffle furnace and a hydrothermal reaction is carried out at a certain temperature. During the hydrothermal reaction, iron oxide particles are generated, and graphene oxide is coated on the surface of the iron oxide particles. Carboxylated carbon nanotubes are attached to the surface of graphene oxide through group reaction. During the process, the reduction reaction of graphene oxide and carboxylated carbon nanotubes occurs simultaneously to form a core-shell multi-level structure. The reaction product is washed clean with ethanol and deionized water and prepared into a deionized water dispersion for later use. 3) Hydrothermal reaction process: The aqueous dispersion prepared in step 2) is poured into a cylindrical mold and placed in an oven for preliminary drying. After drying for a period of time, most of the water has been removed, and a small amount remains. At this time, the solid components in the mold are pressurized by a copper column until they are completely dried, and finally a composite material with graphene, carbon nanotubes and iron oxide as the main components is obtained. 4) Heat treatment process: The composite material obtained in step 3) is transferred to a vacuum tube furnace and heat-treated for a certain period of time in an atmosphere of argon and hydrogen, during which a reduction reaction occurs.

2. The preparation method according to step 1) of claim 1, characterized in that, The volume ratio of concentrated sulfuric acid to phosphoric acid is 9:

1.

3. The preparation method according to step 2) of claim 1, characterized in that, The volume of deionized water used for dissolution is 40-80 ml.

4. The preparation method according to step 2) of claim 1, characterized in that... The hydrothermal reaction is set at a temperature of 200–220°C, and the washing with ethanol and deionized water is performed 3–6 times each.

5. The preparation method according to step 3) of claim 1, characterized in that... The initial drying time is 120–150 minutes.

6. The preparation method according to step 4) of claim 1, characterized in that... The ratio of argon to hydrogen is 10:1, the final heat treatment temperature is 200-400℃, and the holding time is 30-60 min.

7. The graphene / carbon nanotube / ferric oxide composite material prepared by the method according to claim 1, characterized in that, During the hydrothermal reaction, iron oxide particles are generated, and graphene oxide coats the surface of the iron oxide particles. Carboxylated carbon nanotubes are attached to the surface of graphene oxide through group reactions. During the process, reduction reactions of graphene oxide and carboxylated carbon nanotubes occur simultaneously, forming a core-shell multi-level structure. After drying, the material is pressed and shaped to obtain a graphene / carbon nanotube / iron oxide composite material. The internal structure consists of stacked graphene sheets encapsulating iron oxide, with carbon nanotubes cross-connected to form a carbon nanotube network.

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