Two-dimensional copper nanosheet / graphene / aramid fiber composite film material and preparation method and application thereof

Abstract

The invention discloses a two-dimensional copper nanosheet / graphene / aramid fiber composite film material and a preparation method and application thereof, and the method comprises the following steps: (1) adding copper nanosheets and graphene into a mixed solution of poly-p-phenylene terephthamide, potassium hydroxide and dimethyl sulfoxide, and uniformly dispersing to obtain a mixed solution; forming a copper nanosheet / graphene / aramid fiber composite solution; and (2) filtering and drying the copper nanosheet / graphene / aramid fiber composite solution to obtain the two-dimensional copper nanosheet / graphene / aramid fiber composite film material. The preparation method is simple and easy to implement, the cost can be effectively controlled, and the prepared two-dimensional copper nanosheet / graphene / aramid fiber composite film material has efficient electromagnetic shielding performance.

Description

Technical Field

[0001] This invention relates to the field of electromagnetic shielding materials technology, specifically to a two-dimensional copper nanosheet / graphene / aramid composite film material, its preparation method, and its applications. Background Technology

[0002] With the rapid development of electronic devices and communication technologies, electromagnetic interference pollution has become a serious challenge to modern society, threatening the reliable operation of equipment and human health. While traditional polymer-based shielding materials offer processing advantages, they struggle to meet the stringent requirements of flexible wearable electronic devices and highly integrated military equipment for materials that are "lightweight, thin, and flexible." Developing novel electromagnetic shielding materials that combine ultra-thinness, high conductivity, broadband shielding effectiveness, and especially excellent flexibility and wearability is therefore imperative.

[0003] Currently, due to the intrinsic physicochemical differences between the polymer matrix and the conductive filler, and the lack of effective strong chemical bonds, polymer-based electromagnetic shielding films suffer from drawbacks such as weak interfacial adhesion and poor flexibility. Meanwhile, copper, with its excellent conductivity and relatively low cost, has become a key raw material for manufacturing high-performance electromagnetic shielding materials; however, its inherent high density, heavy weight, and poor processability limit its widespread application. Chinese patent CN119776937A discloses a method for preparing an electromagnetic shielding aramid film. The method involves ultrasonically dispersing and filtering aramid nanofibers and carbon nanotubes, pressing them into a membrane, then electroplating the aramid film with an alkaline nickel-copper electroplating solution, followed by washing and flattening to obtain the electromagnetic shielding aramid film. This method is complex, generates pollution during preparation, and is not conducive to industrial-scale production. Chinese patent CN116657442A discloses an electromagnetic shielding meta-aramid paper and its preparation method. This method uses an electrochemical cathode exfoliation method to prepare a graphene mixed solution, wet-forming a meta-aramid base paper, preparing a graphene conductive ink and impregnating the base paper, and then drying and hot-pressing to obtain the electromagnetic shielding meta-aramid paper. While this method produces flexible and multifunctional aramid paper, its shielding performance is low (20-40 dB), limiting its application scenarios.

[0004] Therefore, how to design and develop a material that is simple to process and has both high conductivity and excellent electromagnetic shielding performance is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] The purpose of this invention is to provide a two-dimensional copper nanosheet / graphene / aramid composite film material, its preparation method and uses. It mainly uses electrostatic adsorption and chemical bonding to combine graphene, copper nanosheets and aramid fibers, thereby solving the problem of poor interfacial bonding and improving it.

[0006] In one aspect of the present invention, a method for preparing a two-dimensional copper nanosheet / graphene / aramid composite thin film material is provided. According to an embodiment of the present invention, the preparation method includes the following steps:

[0007] (1) Copper nanosheets and graphene are added to a mixed solution of poly(p-phenylene terephthalamide), potassium hydroxide and dimethyl sulfoxide, and dispersed evenly to form a copper nanosheet / graphene / aramid composite solution.

[0008] (2) The copper nanosheet / graphene / aramid composite solution was filtered and dried to obtain the two-dimensional copper nanosheet / graphene / aramid composite film material.

[0009] In addition, the preparation method of the two-dimensional copper nanosheet / graphene / aramid composite film material according to the above embodiments of the present invention may also have the following additional technical features:

[0010] In some embodiments of the present invention, step (1) of the method for preparing the copper nanosheets includes the following steps:

[0011] Copper nanosheets were prepared by reacting copper chloride dihydrate, glucose, iodine, and hexadecylamine in an oil bath, followed by centrifugation, washing, and drying. The specific steps are as follows: Copper chloride dihydrate, glucose, and iodine were added to deionized water and sonicated to obtain a mixed solution. Hexadecylamine was dissolved in ethanol and added to the mixed solution. The beaker was wrapped with tin foil, and the mixed solution was subjected to an oil bath reaction. The reactants were repeatedly centrifuged and washed with chloroform and deionized water, and then dried to obtain copper nanosheets.

[0012] In the synthesis of two-dimensional copper nanosheets, copper chloride dihydrate serves as the copper source, providing the copper ions required for the reaction and acting as a precursor for the formation of copper nanosheets. Glucose acts as a reducing agent, its aldehyde group being oxidized during the reaction, reducing the copper ions to metallic copper, thereby forming copper nanosheets. Hexadecylamine acts as a surfactant, stabilizing the copper nanosheets. It prevents nanosheet aggregation by adsorbing onto the surface of the copper nanosheets and simultaneously regulates the growth direction of the nanosheets. Iodine acts as a morphology regulator, controlling the morphology of the copper nanosheets to form a sheet-like structure.

[0013] In some embodiments of the present invention, in the solution of the oil bath thermal reaction, the concentration of copper chloride dihydrate is 6.3 mg / mL, the concentration of glucose is 15 mg / mL, the concentration of hexadecylamine is 26.24 g / L, and the concentration of iodide ions is 31.5 μg / mL; the temperature of the oil bath thermal reaction is 100°C, and the time is 12 h. The concentration of copper ions to glucose is approximately 1:2.2, ensuring a suitable copper ion flux. Too high a concentration would lead to excessively rapid nucleation, resulting in small particles or agglomeration; too low a concentration would result in insufficient nucleation and low nanosheet yield, while ensuring sufficient glucose content as a reducing agent. Hexadecylamine, as a surfactant, adsorbs onto the surface of the nascent copper; sufficient quantity can prevent agglomeration and regulate the exposed crystal faces. Iodine acts as a morphology regulator, controlling the zero-dimensional, one-dimensional, and two-dimensional morphologies of the copper nanoparticles. The mechanism is as follows: iodine ions are strongly adsorbed on the Cu{111} crystal plane, inhibiting the growth of this plane and promoting the two-dimensional extension dominated by the {100} plane. When the concentration is too high, it will lead to over-etching, thereby inhibiting the growth of nanosheets. When the concentration is too low, it cannot effectively passivate the {111} plane and tends to generate three-dimensional particles.

[0014] In some embodiments of the present invention, the centrifugation speed is 8000 r / min and the centrifugation time is 4 min; the washing is performed using deionized water and chloroform, with 5 washes using deionized water and 2 washes using chloroform; the drying temperature is 60°C and the drying time is 12 h.

[0015] In some embodiments of the present invention, step (1) is specifically performed as follows: Poly(p-phenylene terephthalamide), potassium hydroxide, and dimethyl sulfoxide are added to deionized water and stirred in a water bath at room temperature to form a homogeneous solution. Copper nanosheets and graphene are then added, and the solution is ultrasonically dispersed. A certain amount of deionized water is added, and the solution is mechanically stirred and then filtered. Deionized water is added to standardize the solution, forming a copper nanosheet / graphene / aramid composite solution. The first stirring time is 12 hours, the ultrasonic time is 5 minutes, and the second stirring time is 30 minutes.

[0016] In this process, poly(p-phenylene terephthalamide) serves as the polymer matrix of aramid, possessing rigid molecular chains and a strong hydrogen bond network, providing the polymer backbone. Potassium hydroxide acts as a chemical activator, deprotonating the hydrogen atoms on the aramid to form negatively charged polyelectrolyte chains. Dimethyl sulfoxide, as a strongly polar aprotic solvent, permeates the aramid fiber bundles, expanding the inter-chain spacing. Finally, deionized water is added to induce electrostatic repulsion in the aramid chains, driving self-exfoliation and forming a stable aramid dispersion. Simultaneously, graphene and copper nanosheets achieve strong electrostatic bonding through π-π conjugation and electrostatic adsorption, fully dispersing in the aramid solution to form a rich and dense nanofiber network, promoting multiple reflections and shielding of electromagnetic waves.

[0017] In step (1): the concentration of poly(p-phenylene terephthalamide) in the mixed solution is 0.5-2 g / L, the concentration of potassium hydroxide is 0.013-0.054 mol / L, and the concentration of dimethyl sulfoxide is 20-300 mL. In the copper nanosheet / graphene / aramid composite solution, the concentration of copper nanosheets is 2-7.5 mg / mL, and the concentration of graphene is 5-8 mg / mL.

[0018] In some embodiments of the present invention, in step (2): the filtration is performed by vacuum filtration for 10 minutes.

[0019] In some embodiments of the present invention, in step (2): the drying temperature is 60°C and the drying time is 1 hour.

[0020] In another aspect of the present invention, the present invention provides a method for preparing the two-dimensional copper nanosheet / graphene / aramid composite film material as described above.

[0021] In another aspect of the invention, the invention proposes the use of a two-dimensional copper nanosheet / graphene / aramid composite film material for preparing electromagnetic shielding materials.

[0022] Compared with the prior art, the beneficial effects of the present invention are:

[0023] 1. This invention prepares an electromagnetic shielding composite film material with aramid fibers as the substrate and copper nanosheets and graphene as conductive fillers via a simple oil bath heating, water bath, and vacuum filtration technique. The aramid solution forms a film on the nanosheet surface, achieving strong electrostatic bonding through π-π conjugation and electrostatic adsorption. Vacuum filtration achieves "directional alignment of nanosheets + in-situ filling of aramid," constructing a long-range ordered hierarchical structure. Consequently, the copper nanosheets and graphene are fully dispersed in the aramid solution, forming a rich and dense nanofiber network, promoting multiple reflections and shielding of electromagnetic waves.

[0024] 2. Copper nanosheet / graphene / aramid composite films, as a new generation of high-performance electromagnetic shielding materials, possess superior comprehensive performance due to their structural advantages: copper nanosheets have a low permeation threshold, and their controllable synthesis can be achieved through "iodine ion-assisted morphology regulation." Their high conductivity is also beneficial for constructing the electromagnetic shielding layer in the composite film. The high aspect ratio of graphene nanosheets provides a long-range conductive network. The synergistic enhancement of graphene and copper nanosheets enables the film to achieve a much stronger electromagnetic shielding performance (EMI SE) than traditional metal foils or coatings, even with a thickness of only 0.2 mm, effectively isolating high-frequency electromagnetic interference. Simultaneously, the aramid substrate provides excellent mechanical strength, flexibility, and folding resistance, allowing it to adapt to complex curved structures and withstand harsh environments without easily breaking.

[0025] 3. The composite thin film material has a shielding performance of 66dB, a thickness of 0.20mm, and an area density of 0.31mg / cm³. 2 It exhibits excellent shielding performance, which is beneficial for the preparation of new electromagnetic shielding materials that are "light, thin and flexible".

[0026] 4. This invention uses green and environmentally friendly raw materials, with controllable costs. The preparation process is highly repeatable, with a short cycle and low energy consumption. No special equipment is required, facilitating large-scale production. The prepared copper nanosheet / graphene / aramid composite film material is lightweight and thin, perfectly meeting the urgent needs of modern electronic devices for miniaturization, lightweighting, and high integration. It is an ideal choice for solving electromagnetic compatibility problems in fields such as 5G communication, high-speed computing chips, precision sensors (such as autonomous driving), wearable devices, and aerospace electronics. Attached Figure Description

[0027] Figure 1 Scanning electron microscope image of the copper nanosheet / graphene / aramid composite film material prepared in Example 1 of this invention;

[0028] Figure 2 This is a scanning electron microscope image of the copper nanosheet / graphene / aramid composite film material prepared in Example 2 of the present invention;

[0029] Figure 3 This is a scanning electron microscope image of the copper nanosheet / graphene / aramid composite film material prepared in Example 3 of the present invention;

[0030] Figure 4 This is a scanning electron microscope image of the copper nanosheet / graphene / aramid composite film material prepared in Example 4 of the present invention;

[0031] Figure 5 This is a scanning electron microscope image of the graphene / aramid composite film material prepared in Comparative Example 1 of this invention.

[0032] Figure 6 The shielding performance diagram of the copper nanosheet / graphene / aramid composite film material prepared in Example 1 of this invention is shown.

[0033] Figure 7 The shielding performance diagram of the copper nanosheet / graphene / aramid composite film material prepared in Example 4 of this invention is shown.

[0034] Figure 8 The shielding performance diagram of the graphene / aramid composite film material prepared in Comparative Example 1 of this invention is shown.

[0035] Figure 9 The infrared spectrum of the graphene / aramid composite film material prepared in Comparative Example 1 of this invention is shown below.

[0036] Figure 10 The infrared spectrum of the copper nanosheet / graphene / aramid composite film material prepared in Example 4 of this invention;

[0037] Figure 11 Optical images of the copper nanosheet / graphene / aramid composite thin film material prepared in Example 4 of this invention. Detailed Implementation

[0038] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0039] Example 1

[0040] A method for preparing a two-dimensional copper nanosheet / graphene / aramid composite thin film material, specifically including the following steps:

[0041] Step 1: Preparation of copper nanosheets

[0042] A first mixed solution was prepared by adding copper chloride dihydrate, glucose, and iodine to deionized water according to the specified ratio. Simultaneously, hexadecylamine was dissolved in ethanol and added to the first mixed solution. The concentrations of copper chloride dihydrate, glucose, hexadecylamine, and iodine ions in the prepared mixed solution were 6.3 mg / mL, 15 mg / mL, 26.24 g / L, and 31.5 μg / mL. The first mixed solution was sonicated for 5 min, and the beaker was wrapped with tin foil and reacted at 100℃ for 12 h. The hydrothermal reaction product was centrifuged and washed five times with deionized water and twice with chloroform. It was then dried at 60℃ for 12 h to obtain copper nanosheets.

[0043] Step 2: Preparation of copper nanosheet / graphene / aramid composite solution

[0044] 0.04 g of poly(p-phenylene terephthalamide), 0.06 g of potassium hydroxide, and 20 mL of dimethyl sulfoxide were added to deionized water and stirred in a water bath at room temperature for 12 h to form a homogeneous solution. Then, the copper nanosheets and graphene prepared above were added, with the mass of copper nanosheets being 0.04 g and the mass of graphene being 0.16 g. The mixture was sonicated for 5 min to ensure uniform dispersion. Deionized water was added, and the mixture was mechanically stirred for 30 min before filtration. 20 mL of deionized water was added to standardize the solution to form a copper nanosheet / graphene / aramid composite solution.

[0045] Step 3: Preparation of copper nanosheet / graphene / aramid composite thin film materials

[0046] The copper nanosheet / graphene / aramid composite solution was vacuum filtered for 10 min and then dried at 60 °C for 1 h to obtain a two-dimensional copper nanosheet / graphene / aramid composite film material with a thickness of 0.23 mm.

[0047] Example 2

[0048] A method for preparing a two-dimensional copper nanosheet / graphene / aramid composite thin film material, specifically including the following steps:

[0049] Step 1: Preparation of copper nanosheets

[0050] A first mixed solution was prepared by adding copper chloride dihydrate, glucose, and iodine to deionized water according to the specified ratio. Simultaneously, hexadecylamine was dissolved in ethanol and added to the first mixed solution. The concentrations of copper chloride dihydrate, glucose, hexadecylamine, and iodine ions in the prepared mixed solution were 6.3 mg / mL, 15 mg / mL, 26.24 g / L, and 31.5 μg / mL. The first mixed solution was sonicated for 5 min, and the beaker was wrapped with tin foil and reacted at 100℃ for 12 h. The hydrothermal reaction product was centrifuged and washed five times with deionized water and twice with chloroform. It was then dried at 60℃ for 12 h to obtain copper nanosheets.

[0051] Step 2: Preparation of copper nanosheet / graphene / aramid composite solution

[0052] 0.6 g of poly(p-phenylene terephthalamide), 0.9 g of potassium hydroxide, and 300 mL of dimethyl sulfoxide were added to deionized water and stirred in a water bath at room temperature for 12 h to form a homogeneous solution. Then, the copper nanosheets and graphene prepared above were added, with a mass of 0.07 g of copper nanosheets and 0.13 g of graphene. The mixture was sonicated for 5 min to ensure uniform dispersion. Deionized water was added, and the mixture was mechanically stirred for 30 min before filtration. 1200 mL of deionized water was added to standardize the solution to form a copper nanosheet / graphene / aramid composite solution.

[0053] Step 3: Preparation of copper nanosheet / graphene / aramid composite thin film materials

[0054] The copper nanosheet / graphene / aramid composite solution was vacuum filtered for 10 min and dried at 60 °C for 1 h to obtain a copper nanosheet / graphene / aramid composite film material with a thickness of 0.26 mm.

[0055] Example 3

[0056] A method for preparing a two-dimensional copper nanosheet / graphene / aramid composite thin film material, specifically including the following steps:

[0057] Step 1: Preparation of copper nanosheets

[0058] A first mixed solution was prepared by adding copper chloride dihydrate, glucose, and iodine to deionized water according to the specified ratio. Simultaneously, hexadecylamine was dissolved in ethanol and added to the first mixed solution. The concentrations of copper chloride dihydrate, glucose, hexadecylamine, and iodine ions in the prepared mixed solution were 6.3 mg / mL, 15 mg / mL, 26.24 g / L, and 31.5 μg / mL. The first mixed solution was sonicated for 5 min, and the beaker was wrapped with tin foil and reacted at 100℃ for 12 h. The hydrothermal reaction product was centrifuged and washed five times with deionized water and twice with chloroform. It was then dried at 60℃ for 12 h to obtain copper nanosheets.

[0059] Step 2: Preparation of copper nanosheet / graphene / aramid composite solution

[0060] 0.04 g of poly(p-phenylene terephthalamide), 0.06 g of potassium hydroxide, and 20 mL of dimethyl sulfoxide were added to deionized water and stirred in a water bath at room temperature for 12 h to form a homogeneous solution. Then, the copper nanosheets and graphene prepared above were added, with a mass of 0.1 g of copper nanosheets and 0.1 g of graphene. The mixture was sonicated for 5 min to ensure uniform dispersion. Deionized water was added, and the mixture was mechanically stirred for 30 min before filtration. 20 mL of deionized water was added to standardize the solution to form a copper nanosheet / graphene / aramid composite solution.

[0061] Step 3: Preparation of copper nanosheet / graphene / aramid composite thin film materials

[0062] The copper nanosheet / graphene / aramid composite solution was vacuum filtered for 10 min and dried at 60 °C for 1 h to obtain a copper nanosheet / graphene / aramid composite film material with a thickness of 0.21 mm.

[0063] Example 4

[0064] A method for preparing a two-dimensional copper nanosheet / graphene / aramid composite thin film material, specifically including the following steps:

[0065] Step 1: Preparation of copper nanosheets

[0066] A first mixed solution was prepared by adding copper chloride dihydrate, glucose, and iodine to deionized water according to the specified ratio. Simultaneously, hexadecylamine was dissolved in ethanol and added to the first mixed solution. The concentrations of copper chloride dihydrate, glucose, hexadecylamine, and iodine ions in the prepared mixed solution were 6.3 mg / mL, 15 mg / mL, 26.24 g / L, and 31.5 μg / mL. The first mixed solution was sonicated for 5 min, and the beaker was wrapped with tin foil and reacted at 100℃ for 12 h. The hydrothermal reaction product was centrifuged and washed five times with deionized water and twice with chloroform. It was then dried at 60℃ for 12 h to obtain copper nanosheets.

[0067] Step 2: Preparation of copper nanosheet / graphene / aramid composite solution

[0068] 0.04 g of poly(p-phenylene terephthalamide), 0.06 g of potassium hydroxide, and 20 mL of dimethyl sulfoxide were added to deionized water and stirred in a water bath at room temperature for 12 h to form a homogeneous solution. Then, the copper nanosheets and graphene prepared above were added, with a mass of 0.15 g of copper nanosheets and 0.15 g of graphene. The mixture was sonicated for 5 min to ensure uniform dispersion. Deionized water was added, and the mixture was mechanically stirred for 30 min before filtration. 20 mL of deionized water was added to standardize the solution to form a copper nanosheet / graphene / aramid composite solution.

[0069] Step 3: Preparation of copper nanosheet / graphene / aramid composite thin film materials

[0070] The copper nanosheet / graphene / aramid composite solution was vacuum filtered for 10 min and dried at 60 °C for 1 h to obtain a copper nanosheet / graphene / aramid composite film material with a thickness of 0.20 mm.

[0071] Comparative Example 1

[0072] A method for preparing a graphene / aramid composite thin film material specifically includes the following steps:

[0073] Step 1: Preparation of graphene / aramid composite solution

[0074] 0.6 g of poly(p-phenylene terephthalamide), 0.9 g of potassium hydroxide, and 300 mL of dimethyl sulfoxide were added to deionized water and stirred in a water bath at room temperature for 12 h to form a homogeneous solution. Then, 0.16 g of graphene was added and sonicated for 5 min to disperse it evenly. Deionized water was added, and the mixture was mechanically stirred for 30 min and then filtered. 1200 mL of deionized water was added and the solution was standardized to form a graphene / aramid composite solution.

[0075] Step 2: Preparation of graphene / aramid composite film materials

[0076] The graphene / aramid composite solution was vacuum filtered for 10 minutes and then dried at 60°C for 1 hour to obtain a graphene / aramid composite film material with a thickness of 0.31 mm.

[0077] The composite thin film materials prepared in Examples 1-4 and Comparative Example 1 were subjected to performance tests:

[0078] 1. The surface morphology of the composite thin film materials prepared in Examples 1-4 and Comparative Example 1 was characterized using a Hitachi SU8020 cold field emission scanning electron microscope. The accelerating voltage used was 3kV.

[0079] like Figure 1 As shown, the surface of the copper nanosheet / graphene / aramid composite film material prepared in Example 1 is rough; as Figure 2 As shown, the surface of the copper nanosheet / graphene / aramid composite film material prepared in Example 2 is relatively rough and dense; as Figure 3 As shown, the copper nanosheet / graphene / aramid composite film material prepared in Example 3 forms a smooth layered structure, with the copper nanosheets randomly distributed on the surface and the graphene / aramid forming a sparse conductive network. Figure 4 As shown, the copper nanosheet / graphene / aramid composite film material prepared in Example 4 exhibits a dense layered structure, in which the high aspect ratio graphene forms a dense conductive pathway, providing an efficient electron migration channel. Figure 5 As shown, the surface of the graphene / aramid composite film material prepared in Example 5 is rough and irregular.

[0080] 2. Using a ROHDE & SCHWARZ vector network analyzer, the shielding performance of the composite thin film materials prepared in Examples 1, 4, and Comparative Example 1 was tested in the 8-12 GHz frequency range using the waveguide method. The shielding performance was obtained. Figure 6-8 .

[0081] like Figure 6 As shown, the copper nanosheet / graphene / aramid composite film material prepared in Example 1 exhibits the best shielding performance of 53 dB, a thickness of 0.23 mm, and an areal density of approximately 0.19 mg / cm³. 2 ;Depend on Figure 7 It can be seen that the optimal shielding performance of the copper nanosheet / graphene / aramid composite film material prepared in Example 4 is 66 dB, with a thickness of 0.20 mm and an areal density of 0.31 mg / cm³. 2 ;like Figure 8As shown, the optimal shielding performance of the graphene / aramid composite film material prepared in Comparative Example 1 is 38 dB. The graphene main network ensures a low-resistance path and enhances ohmic loss. In summary, the interface formed between the copper sheet and graphene induces interfacial polarization, enhancing dielectric loss; therefore, the copper nanosheet / graphene / aramid composite film material has good shielding performance.

[0082] like Figure 9 As shown, the 3600 cm⁻¹ infrared spectrum of the graphene / aramid composite film material... -1 The absorption peak at the position corresponds to the stretching vibration of the hydroxyl group, 1500-1700 cm⁻¹. -1 The absorption peak at the position corresponds to the carbon-oxygen double bond; such as Figure 10 As shown, the absorption peaks of hydroxyl and carbon-oxygen double bonds in the infrared spectrum of the copper nanosheet / graphene / aramid composite film material are significantly weakened, indicating that the oxygen-containing groups are consumed by copper, the hydroxyl groups participate in the coordination reaction, and a stronger interaction is formed between graphene and copper, thus enhancing the binding force.

[0083] like Figure 11 As shown in the optical images, the copper nanosheet / graphene / aramid composite film material can be bent with tweezers without applying a large force, demonstrating its good flexibility.

[0084] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the structure of the present invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. A method for preparing a two-dimensional copper nanosheet / graphene / aramid composite thin film material, characterized in that, Includes the following steps: (1) Copper nanosheets and graphene are added to a mixed solution of poly(p-phenylene terephthalamide), potassium hydroxide and dimethyl sulfoxide, and dispersed evenly to form a copper nanosheet / graphene / aramid composite solution. (2) The copper nanosheet / graphene / aramid composite solution was filtered and dried to obtain the two-dimensional copper nanosheet / graphene / aramid composite film material.

2. The method for preparing the two-dimensional copper nanosheet / graphene / aramid composite thin film material according to claim 1, characterized in that, In step (1), the method for preparing the copper nanosheets includes the following steps: The copper nanosheets were prepared by reacting copper chloride dihydrate, glucose, iodine, and hexadecylamine in an oil bath, followed by centrifugation, washing, and drying.

3. The method for preparing the two-dimensional copper nanosheet / graphene / aramid composite thin film material according to claim 2, characterized in that: In the solution of the oil bath thermal reaction, the concentration of copper chloride dihydrate is 6.3 mg / mL, the concentration of glucose is 15 mg / mL, the concentration of hexadecylamine is 26.24 g / L, and the concentration of iodide ions is 31.5 μg / mL. The oil bath thermal reaction was carried out at a temperature of 100°C for 12 hours.

4. The method for preparing the two-dimensional copper nanosheet / graphene / aramid composite thin film material according to claim 2, characterized in that: The centrifuge speed was 8000 r / min, and the centrifugation time was 4 min; The washing was carried out using deionized water and chloroform, with five washes using deionized water and two washes using chloroform. The drying temperature is 60°C and the time is 12 hours.

5. The method for preparing the two-dimensional copper nanosheet / graphene / aramid composite thin film material according to claim 1, characterized in that, In step (1): the concentration of poly(p-phenylene terephthalamide) in the mixed solution is 0.5-2 g / L, the concentration of potassium hydroxide is 0.013-0.054 mol / L, and the concentration of dimethyl sulfoxide is 20-300 mL.

6. The method for preparing the two-dimensional copper nanosheet / graphene / aramid composite thin film material according to claim 1, characterized in that, In step (1): the concentration of copper nanosheets in the copper nanosheet / graphene / aramid composite solution is 2-7.5 mg / mL, and the concentration of graphene is 5-8 mg / mL.

7. The method for preparing the two-dimensional copper nanosheet / graphene / aramid composite thin film material according to claim 1, characterized in that, In step (2): the filtration is performed by vacuum filtration, and the filtration time is 10-30 minutes.

8. The method for preparing the two-dimensional copper nanosheet / graphene / aramid composite thin film material according to claim 1, characterized in that, In step (2): the drying temperature is 60℃ and the drying time is 1h.

9. A two-dimensional copper nanosheet / graphene / aramid composite film material prepared by the preparation method of any one of claims 1-8.

10. The use of the two-dimensional copper nanosheet / graphene / aramid composite film material according to claim 9, characterized in that: The two-dimensional copper nanosheet / graphene / aramid composite film material is used to prepare electromagnetic shielding materials.

Images