Preparation method of nano composite material with three-dimensional network structure and nano composite material
By constructing a three-dimensional rGO-CNTs-BN network structure, the problems of high density, narrow bandwidth and poor impedance matching of traditional absorbing materials were solved, and the improvement of broadband electromagnetic wave absorption performance and cost control were achieved.
Patent Information
- Application Number
- CN202510755169.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-06
- Publication Date
- 2025-09-12
AI Technical Summary
Traditional absorbing materials have high density, narrow bandwidth and poor weather resistance, making it difficult to meet the needs of lightweight and broadband absorption. Single graphene or carbon nanotubes are difficult to cover the multi-band requirements of complex electromagnetic environments due to poor impedance matching and a single loss mechanism.
The rGO-CNTs-BN three-dimensional network structure was constructed by ball milling, and BN was embedded in the rGO-CNTs conductive network to form a microscopic impedance gradient layer, activating the interface polarization, conductivity loss and multiple scattering mechanism, and improving the impedance matching and absorption performance.
It significantly broadens the absorption band, meets the broadband requirements in complex electromagnetic environments, reduces preparation energy consumption and costs, and has good potential for large-scale production.
Smart Images
Figure CN120640658A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of material technology, and in particular to a preparation method of a three-dimensional network structure nanocomposite material and the nanocomposite material. Background Art
[0002] With the widespread use of electronic devices and communications equipment, problems such as signal interruptions and data transmission errors caused by electromagnetic interference (EMI) are becoming increasingly serious, creating an urgent need for high-performance absorbing materials. Traditional absorbing materials such as ferrite and metal powders suffer from high density, narrow bandwidth, and poor weather resistance, making them difficult to meet the requirements of lightweight and broadband absorption.
[0003] Graphene, with its two-dimensional honeycomb structure, high specific surface area, and excellent conductivity, can effectively attenuate electromagnetic waves through dielectric loss. Its lightweight nature makes it suitable for applications in aerospace and other fields. Carbon nanotubes, due to their one-dimensional tubular structure, tunable conductivity, and multiple reflection mechanisms, show significant potential in microwave-absorbing composite materials.
[0004] The high intrinsic conductivity of single graphene or carbon nanotubes results in poor impedance matching, leading to significant reflection rather than absorption of electromagnetic waves on the material surface. Furthermore, their loss mechanism is limited, and their effective absorption bandwidth (RL < -10dB) is typically less than 5GHz, making it difficult to cover the multi-band requirements of complex electromagnetic environments. Furthermore, the tendency of graphene and carbon nanotubes to agglomerate further limits the optimization of their absorption performance. Summary of the Invention
[0005] The embodiments of the present application solve the problems raised in the background art by providing a method for preparing a three-dimensional network structure nanocomposite material and a nanocomposite material.
[0006] In a first aspect, the present invention provides a method for preparing a three-dimensional network structure nanocomposite material, comprising the following steps: S1: mixing rGO, CNTs and an organic solvent, and cross-linking the rGO and CNTs by ball milling to form a continuous rGO-CNTs conductive network to obtain a first mixture; S2: adding BN to the first mixture, and embedding the BN into the gaps of the rGO-CNTs conductive network in the form of discs by ball milling to construct a three-dimensional network structure, thereby obtaining a second mixture; S3: drying the second mixture to remove the organic solvent to obtain a dry product; S4: Grinding the dried product to obtain a rGO-CNTs-BN three-dimensional network structure nanocomposite material.
[0007] In combination with the first aspect, in a possible implementation, the ball milling speed in steps S1 and S2 is both 200-400 r / min, and the ball milling time is both 3-7 h.
[0008] In combination with the first aspect, in a possible implementation, the drying temperature in step S3 is 80-120° C., and the drying time is 3-5 hours.
[0009] In combination with the first aspect, in a possible implementation, the organic solvent is anhydrous ethanol.
[0010] In combination with the first aspect, in a possible implementation, the mass ratio of the rGO to the CNTs is 1:1-5.
[0011] In combination with the first aspect, in a possible implementation, the mass ratio of the rGO to the CNTs is 1:4.
[0012] In combination with the first aspect, in a possible implementation, the mass ratio of the total mass of the rGO and the CNTs to the mass of the BN is 1:1-3.
[0013] In combination with the first aspect, in a possible implementation, the mass ratio of the total mass of the rGO and the CNTs to the mass of the BN is 2:3.
[0014] In the second aspect, an embodiment of the present application provides a nanocomposite material, which is prepared according to the preparation method of the three-dimensional network structure nanocomposite material described in the first aspect or any possible implementation method of the first aspect, and includes a three-dimensional network structure in which an rGO-CNTs conductive network and BN are mutually embedded, wherein BN is embedded in the gaps of the rGO-CNTs conductive grid in the form of discs; the mass ratio of the rGO to the CNTs is 1:4, and the mass ratio of the total mass of the rGO and the CNTs to the BN is 2:3.
[0015] One or more technical solutions provided in the embodiments of this application have at least the following technical effects: This application successfully constructs a three-dimensional rGO-CNTs-BN network structure through step-by-step ball milling, breaking the key bottleneck of single carbon materials in the field of electromagnetic wave absorption. Specifically, the BN insulator is embedded in the rGO-CNTs conductive network to form a microscopic impedance gradient layer, which greatly improves the impedance matching between the material and free space, prompting the electromagnetic wave to transition from a reflection state to an efficient absorption state, laying a key foundation for improving absorption performance. At the same time, this three-dimensional network structure activates multiple loss mechanisms such as interface polarization, conductivity loss, and multiple scattering. These mechanisms work together to effectively broaden the absorption band, which can fully meet the broadband requirements in complex electromagnetic environments.
[0016] The entire preparation process utilizes physical methods at room temperature and pressure, requiring only ball milling and drying, without the need for high temperature, high pressure, or complex chemical modifications. This significantly reduces energy consumption and equipment requirements. Furthermore, raw material dispersion, structure construction, and organic solvent removal are all integrated, significantly shortening the preparation cycle.
[0017] From the perspective of technical effects, on the one hand, in order to address the problem that single rGO and CNTs have poor impedance matching and narrow absorption bandwidth due to their high conductivity, which makes them difficult to meet the application requirements of complex electromagnetic environments, the introduction of BN by ball milling and the construction of a three-dimensional network structure effectively improve the impedance matching characteristics of the composite material and significantly enhance its absorption performance. On the other hand, this preparation process is simple, the operation is not complicated, the production cycle is greatly shortened, and the cost of obtaining and processing raw materials is low. The overall preparation cost is effectively controlled, and it has good large-scale production potential and industrial application prospects. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following is a brief introduction to the drawings required for use in the description of the embodiments of the present application. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.
[0019] Figure 1 This is a low-magnification scanning electron microscope (SEM) image of the nanocomposite material prepared according to Example 1; Figure 2 This is a high-magnification scanning electron microscope (SEM) image of the nanocomposite material prepared according to Example 1; Figure 3 This is a low-magnification scanning electron microscope (SEM) image of a single component BN; Figure 4 This is a low-magnification scanning electron microscope (SEM) image of single-component CNTs; Figure 5 This is a low-magnification scanning electron microscope (SEM) image of single-component rGO. DETAILED DESCRIPTION
[0020] The following will be combined with the accompanying drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are part of the embodiments of this application, not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of this application.
[0021] In the description of the embodiments of the present application, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limitations on the present application. The terms "first", "second" and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance. In addition, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be a communication between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.
[0022] The present invention provides a method for preparing a three-dimensional network structure nanocomposite material, comprising the following steps S1 to S4: S1: rGO (reduced graphene oxide), CNTs (carbon nanotubes) and an organic solvent are mixed, and the rGO and CNTs are cross-linked by ball milling to form a continuous rGO-CNTs conductive network to obtain a first mixture.
[0023] S2: Adding BN (boron nitride) to the first mixture, and embedding the BN into the gaps of the rGO-CNTs conductive network in the form of discs through ball milling to construct a three-dimensional network structure to obtain the second mixture; S3: Drying the second mixture to remove the organic solvent to obtain a dry product.
[0024] S4: The dried product was ground to obtain rGO-CNTs-BN three-dimensional network structure nanocomposite material.
[0025] Specifically, the dried product is placed in a grinding jar and ground into a fine powder.
[0026] It should be noted that this application successfully constructed a three-dimensional rGO-CNTs-BN network structure through step-by-step ball milling, breaking the key bottleneck of single carbon materials in the field of electromagnetic wave absorption in one fell swoop. Specifically, the BN insulator is embedded in the rGO-CNTs conductive network to form a microscopic impedance gradient layer, which greatly improves the impedance matching between the material and free space, prompting electromagnetic waves to transform from a reflection state to an efficient absorption state, laying a key foundation for improving absorption performance. At the same time, this three-dimensional network structure activates multiple loss mechanisms such as interface polarization, conductivity loss, and multiple scattering. These mechanisms work together to effectively broaden the absorption band, which can fully meet the broadband requirements in complex electromagnetic environments.
[0027] The entire preparation process utilizes physical methods at room temperature and pressure, requiring only ball milling and drying, without the need for high temperature, high pressure, or complex chemical modifications. This significantly reduces energy consumption and equipment requirements. Furthermore, raw material dispersion, structure construction, and organic solvent removal are all integrated, significantly shortening the preparation cycle.
[0028] From the perspective of technical effects, on the one hand, in order to address the problem that single rGO and CNTs have poor impedance matching and narrow absorption bandwidth due to their high conductivity, which makes them difficult to meet the application requirements of complex electromagnetic environments, the introduction of BN by ball milling and the construction of a three-dimensional network structure effectively improve the impedance matching characteristics of the composite material and significantly enhance its absorption performance. On the other hand, this preparation process is simple, the operation is not complicated, the production cycle is greatly shortened, and the cost of obtaining and processing raw materials is low. The overall preparation cost is effectively controlled, and it has good large-scale production potential and industrial application prospects.
[0029] In the embodiment of the present application, the ball milling speed in steps S1 and S2 is 200-400 r / min, and the ball milling time is 3-7 h.
[0030] It should be noted that the appropriate rotation speed range can ensure that rGO, CNTs and the subsequently added BN are fully mixed and interacted during the ball milling process, effectively construct the rGO-CNTs conductive network and enable BN to be accurately embedded in the form of discs to form a three-dimensional network structure, without causing material structure damage or energy consumption surge due to excessively high rotation speed; the appropriate time range ensures that the ball milling reaction is fully carried out, avoiding incomplete reaction and unsatisfactory structure construction due to too short time, and preventing time waste and cost increase caused by too long time. Overall, while ensuring the excellent performance of the composite material, it takes into account both preparation efficiency and cost-effectiveness.
[0031] In the embodiment of the present application, the drying temperature in step S3 is 80-120° C., and the drying time is 3-5 hours.
[0032] This temperature range can not only effectively remove the organic solvent in the second mixture and avoid solvent residue caused by too low a temperature, which in turn affects the performance of the composite material, but also prevent the three-dimensional network structure of rGO-CNTs-BN from being destroyed or deformed due to too high a temperature.
[0033] At the same time, a drying time of 3-5 hours ensures a sufficient and stable organic solvent removal process, preventing both incomplete organic solvent removal due to a too short drying time and unnecessary energy consumption and extended preparation cycles due to a too long drying time.
[0034] Under the premise of ensuring the stable quality of composite materials, the preparation efficiency is effectively improved and the production cost is reduced.
[0035] In the embodiment of the present application, the organic solvent is anhydrous ethanol.
[0036] It should be noted that anhydrous ethanol has good solubility and can fully disperse raw materials such as rGO and CNTs, allowing them to be evenly mixed during the ball milling process, providing favorable conditions for building a stable conductive network and subsequent BN embedding; its volatility is moderate, and combined with drying conditions of 80-120°C and 3-5h, it can quickly and thoroughly remove organic solvents, avoiding residual adverse effects on the performance of the composite material, and will not cause unstable material structure due to excessive volatilization; at the same time, anhydrous ethanol has low toxicity, high safety, is friendly to operators and the environment, and has relatively low cost. While ensuring the smooth progress of the preparation process and excellent performance of the composite material, it also takes into account environmental protection and economic benefits.
[0037] In the examples of the present application, the mass ratio of rGO to CNTs is 1:1-5.
[0038] In the examples of the present application, the mass ratio of rGO to CNTs is 1:4.
[0039] In the examples of the present application, the mass ratio of the total mass of rGO and CNTs to the mass of BN is 1:1-3.
[0040] In the examples of the present application, the mass ratio of the total mass of rGO and CNTs to the mass of BN is 2:3.
[0041] This embodiment of the present application provides a nanocomposite material, prepared according to the aforementioned method for preparing a three-dimensional network nanocomposite material. The nanocomposite material comprises a three-dimensional network structure of an intercalated rGO-CNT conductive network and BN, wherein the BN is embedded in the gaps of the rGO-CNT conductive network in the form of discs. The mass ratio of rGO to CNTs is 1:4, and the mass ratio of the combined rGO and CNTs to BN is 2:3.
[0042] It should be noted that the disc-shaped BN is evenly distributed in the gaps of the rGO-CNTs conductive grid, which accurately adjusts the electromagnetic parameters of the material, effectively improves the impedance matching characteristics, makes it easier for electromagnetic waves to enter the interior of the material, and reduces reflection; at the same time, this special structure activates multiple loss mechanisms such as interface polarization, conductivity loss, and multiple scattering. The various mechanisms work together to broaden the absorption band, which can meet the broadband requirements in complex electromagnetic environments; in addition, the embedding of BN also enhances the structural stability of the composite material, improving its reliability and durability in practical applications.
[0043] Example 1: A method for preparing a three-dimensional network structure nanocomposite material, comprising: S1: Weigh 0.4 g of reduced graphene oxide (rGO), 1.6 g of carbon nanotubes (CNTs), and an appropriate amount of anhydrous ethanol into a ball mill and mill at 300 r / min for 5 h to crosslink the rGO and CNTs to form a uniformly dispersed rGO-CNTs conductive network, thereby obtaining a first mixture.
[0044] S2: Add 3 g of boron nitride (BN) to the first mixture and continue ball milling at 300 r / min for 5 h to cause BN to embed into the gaps of the rGO-CNTs conductive network in the form of discs, constructing a three-dimensional network structure to obtain the second mixture.
[0045] S3: The second mixture was placed in an oven at 90° C. and dried for 4 h to completely remove the anhydrous ethanol and obtain a dry product.
[0046] S4: Grind the dried product into fine powder to obtain rGO-CNTs-BN three-dimensional network structure nanocomposite material.
[0047] In order to comprehensively evaluate the electromagnetic wave absorption performance of the nanocomposite prepared in this application, the composite material was uniformly mixed with 85wt.% paraffin wax to prepare a test sample. Subsequently, the complex dielectric constant of the test sample was tested with the help of a vector network analyzer. Based on the obtained electromagnetic parameter data, the reflection loss of the composite material in the 2-18GHz frequency band was further calculated. The test results show that the minimum reflection loss value RL of the composite material in this frequency band is min Reaching -50.80dB, such an excellent value strongly proves its excellent electromagnetic wave absorption ability.
[0048] Example 2: A method for preparing a three-dimensional network structure nanocomposite material, comprising: S1: Weigh 0.8 g of reduced graphene oxide (rGO), 1.2 g of carbon nanotubes (CNTs), and an appropriate amount of anhydrous ethanol into a ball mill and mill at 300 r / min for 5 h to crosslink the rGO and CNTs to form a uniformly dispersed rGO-CNTs conductive network, thereby obtaining a first mixture.
[0049] S2: Add 3 g of boron nitride (BN) to the first mixture and continue ball milling at 300 r / min for 5 h to cause BN to embed into the gaps of the rGO-CNTs conductive network in the form of discs, constructing a three-dimensional network structure to obtain the second mixture.
[0050] S3: The second mixture was placed in an oven at 90° C. and dried for 4 h to completely remove the anhydrous ethanol and obtain a dry product.
[0051] S4: Grind the dried product into fine powder to obtain rGO-CNTs-BN three-dimensional network structure nanocomposite material.
[0052] Similarly, in order to fully evaluate the electromagnetic wave absorption performance of the composite material, it was evenly mixed with 85wt.% paraffin wax to prepare a test sample, and the test and calculation were carried out according to the above method. The test results show that the minimum reflection loss value RL of the composite material in the 2-18GHz frequency band is min Reaching -42.20dB, it shows that its electromagnetic wave absorption ability is good.
[0053] Example 3: A method for preparing a three-dimensional network structure nanocomposite material, comprising: S1: Weigh 1.2 g of reduced graphene oxide (rGO), 0.8 g of carbon nanotubes (CNTs), and an appropriate amount of anhydrous ethanol into a ball mill and mill at 300 r / min for 5 h to crosslink the rGO and CNTs to form a uniformly dispersed rGO-CNTs conductive network, thereby obtaining a first mixture.
[0054] S2: Add 3 g of boron nitride (BN) to the first mixture and continue ball milling at 300 r / min for 5 h to cause BN to embed into the gaps of the rGO-CNTs conductive network in the form of discs, constructing a three-dimensional network structure to obtain the second mixture.
[0055] S3: The second mixture was placed in an oven at 90° C. and dried for 4 h to completely remove the anhydrous ethanol and obtain a dry product.
[0056] S4: Grind the dried product into fine powder to obtain rGO-CNTs-BN three-dimensional network structure nanocomposite material.
[0057] Similarly, in order to fully evaluate the electromagnetic wave absorption performance of the composite material, it was evenly mixed with 85wt.% paraffin wax to prepare a test sample, and the test and calculation were carried out according to the above method. The test results show that the minimum reflection loss value RL of the composite material in the 2-18GHz frequency band is min It is -10.15dB, indicating that its electromagnetic wave absorption ability is weak.
[0058] Example 4: A method for preparing a three-dimensional network structure nanocomposite material, comprising: S1: Weigh 1.6 g of reduced graphene oxide (rGO), 0.4 g of carbon nanotubes (CNTs), and an appropriate amount of anhydrous ethanol into a ball mill and mill at 300 r / min for 5 h to crosslink the rGO and CNTs to form a uniformly dispersed rGO-CNTs conductive network, thereby obtaining a first mixture.
[0059] S2: Add 3 g of boron nitride (BN) to the first mixture and continue ball milling at 300 r / min for 5 h to cause BN to embed into the gaps of the rGO-CNTs conductive network in the form of discs, constructing a three-dimensional network structure to obtain the second mixture.
[0060] S3: The second mixture was placed in an oven at 90° C. and dried for 4 h to completely remove the anhydrous ethanol and obtain a dry product.
[0061] S4: Grind the dried product into fine powder to obtain rGO-CNTs-BN three-dimensional network structure nanocomposite material.
[0062] The test results show that the minimum reflection loss value RL of the composite material in the 2-18GHz frequency band is min It is -16.40dB, indicating that its electromagnetic wave absorption ability is average.
[0063] This application prepares a series of rGO-CNTs-BN nanocomposites with three-dimensional network structures by adjusting the mass ratio of reduced graphene oxide (rGO) and carbon nanotubes (CNTs), and systematically evaluates their electromagnetic wave absorption performance in the 2-18GHz frequency band. The experimental results show that the ratio of rGO to CNTs has a significant effect on the wave absorption performance of the composite material. Among them, Example 1 using a ratio of rGO:CNTs = 1:4 shows the best performance: when the matching thickness is 2.20mm and the frequency is 13.36GHz, its reflection loss is the minimum (RL min ) is as low as -50.80dB; while the absorption capability of Example 3 with rGO:CNTs=3:2 is relatively weak.
[0064] To reveal the microscopic mechanism of the performance differences of composite materials, Figure 1 and Figure 2 Low- and high-magnification SEM images of the composite material from Example 1 are presented. The images clearly show that boron nitride (BN, white discs) is uniformly and densely embedded within the conductive network of reduced graphene oxide (rGO) and carbon nanotubes (CNTs), forming a unique three-dimensional network. This structure effectively reduces electromagnetic wave loss and is a key factor in the material's high performance.
[0065] As a comparison, Figure 3 、 Figure 4 and Figure 5 The low-magnification SEM morphologies of single components BN, CNTs and rGO are shown respectively, from which it can be seen that rGO has a two-dimensional sheet structure, CNTs has a one-dimensional tubular structure, and BN has a two-dimensional circular sheet structure.
[0066] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other. Each embodiment focuses on the differences from other embodiments.
[0067] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit the present application. Although the present application has been described in detail with reference to the aforementioned embodiments, a person of ordinary skill in the art should understand that the technical solutions described in the aforementioned embodiments can still be modified, or some or all of the technical features therein can be replaced by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the present application.
Claims
1. A method for preparing a three-dimensional network structure nanocomposite material, characterized in that: The steps include: S1: mixing rGO, CNTs and an organic solvent, and cross-linking the rGO and CNTs by ball milling to form a continuous rGO-CNTs conductive network to obtain a first mixture; S2: adding BN to the first mixture, and embedding the BN into the gaps of the rGO-CNTs conductive network in the form of discs by ball milling to construct a three-dimensional network structure, thereby obtaining a second mixture; S3: drying the second mixture to remove the organic solvent to obtain a dry product; S4: Grinding the dried product to obtain a rGO-CNTs-BN three-dimensional network structure nanocomposite material.
2. The method for preparing a three-dimensional network structure nanocomposite material according to claim 1, characterized in that: The ball milling speed in steps S1 and S2 is 200-400 r / min, and the ball milling time is 3-7 h.
3. The method for preparing the three-dimensional network structure nanocomposite material according to claim 1, characterized in that: The drying temperature in step S3 is 80-120° C., and the drying time is 3-5 hours.
4. The method for preparing a three-dimensional network structure nanocomposite material according to claim 1, characterized in that: The organic solvent is anhydrous ethanol.
5. The method for preparing a three-dimensional network structure nanocomposite material according to claim 1, characterized in that: The mass ratio of the rGO to the CNTs is 1:1-5.
6. The method for preparing a three-dimensional network structure nanocomposite material according to claim 5, characterized in that: The mass ratio of the rGO to the CNTs is 1:
4.
7. The method for preparing a three-dimensional network structure nanocomposite material according to claim 5, characterized in that: The mass ratio of the total mass of the rGO and the CNTs to the BN is 1:1-3.
8. The method for preparing a three-dimensional network structure nanocomposite material according to claim 7, characterized in that: The mass ratio of the total mass of the rGO and the CNTs to the mass of the BN is 2:
3.
9. A nanocomposite material, characterized in that: The method for preparing a three-dimensional network structure nanocomposite material according to any one of claims 1 to 8 comprises a three-dimensional network structure in which an rGO-CNTs conductive network and BN are mutually embedded, wherein BN is embedded in the gaps of the rGO-CNTs conductive grid in the form of discs; the mass ratio of the rGO to the CNTs is 1:4, and the mass ratio of the total mass of the rGO and the CNTs to the BN is 2:3.