Electromagnetic shielding material with macroscopic conical hole structure and preparation method and application thereof
The macroscopic conical hole structure of graphene/polylactic acid composite material was prepared by 3D printing technology, which solved the problems of lightweighting and high performance of traditional electromagnetic shielding materials, and achieved rapid preparation and efficient electromagnetic shielding effect.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- NANTONG UNIV
- Filing Date
- 2026-03-23
- Publication Date
- 2026-06-26
AI Technical Summary
Traditional electromagnetic shielding materials are dense, have poor flexibility, and are prone to corrosion. Furthermore, composite materials are complex to process and costly, making it difficult to meet the demands of modern electronic devices for lightweight and high performance.
A graphene/polylactic acid composite material with a macroscopic conical pore structure was prepared using 3D printing technology. The composite filament was prepared by melt spinning and formed into a macroscopic conical pore array structure in a 3D printer. Combining the conductivity of graphene and the biodegradability of polylactic acid, a continuous conductive network was formed.
It has achieved lightweight, high-performance electromagnetic shielding materials with fast printing speed, low equipment precision requirements, macroscopic porous structure that is not easily blocked, good environmental adaptability, and electromagnetic waves are reflected multiple times inside the material to enhance shielding performance.
Smart Images
Figure CN122278162A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of electromagnetic shielding, and relates to an electromagnetic shielding material with a macroscopic conical hole structure, its preparation method and application. Background Technology
[0002] Traditional electromagnetic shielding materials mainly include metal-based materials (such as copper, aluminum, and silver) and ferrites. While these materials offer good electromagnetic shielding performance, they generally suffer from high density, poor flexibility, and susceptibility to corrosion, making it difficult to meet the demands of modern electronic devices for lightweight and high performance. Furthermore, although some composite materials improve shielding performance through high levels of conductive fillers, they still face challenges such as complex processing, high cost, or insufficient environmental compatibility.
[0003] To overcome these limitations, researchers have turned their attention to novel nanomaterials that provide conductive properties, such as graphene and carbon nanotubes. These materials not only possess excellent conductivity and electromagnetic shielding performance, but also exhibit lightweight, high specific surface area, good chemical stability, and tunable dielectric properties, offering new possibilities for the development of next-generation high-performance electromagnetic shielding materials. Graphene nanosheets (GNPs) possess excellent conductivity and a high specific surface area. Polylactic acid (PLA) exhibits good biodegradability, tensile strength, and ductility. The combination of GNPs and PLA provides a new approach to balancing electromagnetic shielding effectiveness with the needs of sustainable development.
[0004] Numerous studies have shown that interfacial structures within materials can effectively extend the propagation path of electromagnetic waves and enhance their interaction, thereby improving electromagnetic shielding performance. Designing porous structures within materials using template methods or foaming methods has become an effective approach for preparing lightweight and efficient electromagnetic shielding materials. However, template methods face challenges in precisely controlling pore size and distribution, while foaming techniques can produce highly random pore structures, reducing the material's mechanical strength. Furthermore, porous materials suffer from defects such as discontinuous conductive networks and difficulty in controlling pore structures, which severely compromise the stability of their electromagnetic shielding performance. Three-dimensional (3D) printing technology, through a layer-by-layer deposition process, directly transforms three-dimensional digital models into solid objects, providing a novel solution for preparing porous electromagnetic shielding materials. This technology ensures precise manipulation and adjustment of the material structure. In terms of material selection, 3D printing can flexibly combine conductive fillers with polymer matrices, forming a continuous conductive network while maintaining a porous structure. Due to its moldless manufacturing characteristics, 3D printing significantly shortens product development cycles and offers high material utilization, aligning with the principles of sustainable green manufacturing. This advanced manufacturing method, which combines material properties with structural design, provides an innovative solution for developing novel, lightweight, and high-performance electromagnetic interference shielding materials. Because micron-scale structures require extremely fine nozzles, high-precision motion control systems, and extremely stringent process parameters, the 3D printing process is time-consuming and generally places high demands on the equipment.
[0005] Therefore, developing an electromagnetic shielding material with macroscopic (millimeters-scale) aperture has significant theoretical and practical value. Summary of the Invention
[0006] In view of the shortcomings of the prior art, the present invention provides an electromagnetic shielding material with a macroscopic conical hole structure, its preparation method and application. The electromagnetic shielding material has excellent electromagnetic shielding performance, low preparation cost and can be used for electromagnetic shielding.
[0007] In a first aspect, the present invention provides a method for preparing an electromagnetic shielding material having a macroscopic conical aperture array structure, the method comprising the following steps:
[0008] S1. Add graphene nanosheets and polylactic acid particles to dichloromethane and stir with a magnetic stirrer until the polylactic acid is completely dissolved to obtain a graphene composite dispersion;
[0009] S2. Place the graphene composite dispersion in a fume hood and allow it to dry naturally at room temperature. After the dichloromethane solvent has completely evaporated, a graphene / polylactic acid composite material is obtained.
[0010] S3. The obtained graphene / polylactic acid composite material is shredded and fed into a benchtop extruder, and composite filaments for 3D printing are extruded by melt spinning.
[0011] S4. Create a model for 3D printing on a computer, feed the composite filament into the 3D printer, and use the computer to control the 3D printer to process the electromagnetic shielding material with a macroscopic conical hole array structure.
[0012] In some embodiments of the present invention, in step S1, the mass ratio of graphene to polylactic acid is 5:95 to 15:85, and the mass ratio of solid material to dichloromethane is 1:4 to 1:10, wherein the solid material is graphene and polylactic acid.
[0013] In some embodiments of the present invention, in step S3, the barrel temperature of the benchtop extruder is 195°C, the curing temperature is room temperature, and the diameter of the extruded fiber is 1.75 mm.
[0014] In some embodiments of the present invention, in step S4, a printing material model is created using three-dimensional modeling software on a computer. The conical holes are at the same height as the printing material model, with a bottom radius of 0.5~3mm and a center distance of 4~5mm between adjacent conical holes.
[0015] In some embodiments of the present invention, in step S4, the printer needle diameter is 0.4 mm, the printing speed is 30 mm / s, the needle temperature is 200°C, and the print bed temperature is 50°C.
[0016] In a second aspect, the present invention provides an electromagnetic shielding material having a macroscopic conical hole array structure prepared by the above-described preparation method.
[0017] In a third aspect, the present invention provides an application of the above-mentioned electromagnetic shielding material with a macroscopic conical hole array structure in electromagnetic shielding.
[0018] Compared with existing technologies, this invention uses 3D printing technology to prepare composite materials with conical hole structures at the millimeter level. This results in faster printing speeds, lower requirements for equipment precision, higher cost-effectiveness, and less clogging of the macroscopic pore structure during application, leading to better environmental adaptability. The macroscopic conical hole structure facilitates the penetration of electromagnetic waves into the graphene / polylactic acid composite material, preventing reflection at the surface due to impedance mismatch. Electromagnetic waves incident inside the material are reflected at the solid / gas interface. Due to the characteristics of the conical hole structure, a large number of reflected electromagnetic waves are confined within the material and undergo multiple reflections, extending the propagation path of the electromagnetic waves, increasing the interaction between the electromagnetic waves and the composite material, and thus improving the electromagnetic shielding performance of the composite material. Attached Figure Description
[0019] These and / or other aspects and advantages of the present invention will become apparent and readily understood from the following description of preferred embodiments taken in conjunction with the accompanying drawings, in which:
[0020] Figure 1 A schematic diagram illustrating the process of preparing the electromagnetic shielding material with a macroscopic conical hole structure provided by the present invention;
[0021] Figure 2 Photographs, microscopic cross-sections, and surface morphology of the GNP / PLA composite filaments prepared in Example 1 of this invention;
[0022] Figure 3 The printed model and photograph of the conical hole array of this embodiment 1 are shown.
[0023] Figure 4 This is a printed model and a photograph of the printed object for Comparative Example 2;
[0024] Figure 5 A printed model and photograph of the actual printed object for Comparative Example 3;
[0025] Figure 6 The printed model and photograph of the actual printed object are shown in Comparative Example 4.
[0026] Figure 7 A printed model and photograph of the actual printed object for Comparative Example 5;
[0027] Figure 8 For comparison 6, here are the printed model and a photograph of the printed object;
[0028] Figure 9 SE in the X-band for seven different CNP / PLA composite materials, and average SE in the X-band. A SE R Comparison chart and comparison chart of average A, R, and T values in the X-band. Detailed Implementation
[0029] The technical solution of the present invention will be further described in detail below through embodiments and in conjunction with the accompanying drawings. In this specification, the same or similar reference numerals indicate the same or similar components. The following description of the embodiments of the present invention with reference to the accompanying drawings is intended to explain the overall inventive concept of the present invention and should not be construed as a limitation thereof.
[0030] It should be noted that the terms used in this application are generally those commonly used by those skilled in the art. If there is any inconsistency with commonly used terms, the terms used in this application shall prevail.
[0031] like Figure 1 As shown, an embodiment of the first aspect of the present invention provides a method for preparing a macroscopic conical hole structure composite material, comprising the following steps:
[0032] S1. Add graphene nanosheets and polylactic acid particles to dichloromethane and stir with a magnetic stirrer until the polylactic acid is completely dissolved to obtain a graphene composite dispersion.
[0033] S2. Place the graphene composite dispersion in a fume hood and allow it to dry naturally at room temperature until the dichloromethane solvent has completely evaporated to obtain the graphene / polylactic acid composite material.
[0034] S3. The obtained composite material is shredded and fed into a benchtop extruder, and processed into composite filaments for 3D printing by melt spinning.
[0035] S4. Create a model for 3D printing on a computer, feed the composite filament into the 3D printer, and use the computer to control the 3D printer to process the composite material with a macroscopic conical hole structure.
[0036] Example 1
[0037] (1) Add 15g GNP and 85g PLA to 600g dichloromethane solvent, place the mixture in a fume hood and stir thoroughly with a magnetic stirrer to completely dissolve PLA and uniformly disperse GNP to obtain a GNP composite dispersion.
[0038] (2) The GNP composite dispersion was placed in a fume hood and dried naturally at room temperature until the dichloromethane solvent was completely evaporated to obtain the GNP / PLA composite material.
[0039] (3) The obtained GNP / PLA composite material was shredded and then placed in a benchtop extruder. The barrel temperature of the benchtop extruder was 195℃ and the curing temperature was room temperature. The diameter of the obtained filament was 1.75mm. Figure 2 Photographs, microscopic cross-sections, and surface morphology of the filament are shown.
[0040] Photographs of the obtained filaments are as follows Figure 2 As shown in (a), the microscopic cross-section and surface morphology of the filament are as follows: Figure 2 As shown in (b) and 2(c).
[0041] (4) Use 3D modeling software on a computer to create a model of the printing material. The model's length, width, and height are 34mm × 24mm × 3mm. The radius of the conical holes is 2mm, and the height is 3mm. The matrix of conical holes distributed in the model is 6 × 4, and the center distance between adjacent conical holes is 4.5mm. The surface and cross-section of the resulting model are as follows: Figure 3 As shown in Figure (a). The model file is exported in STL format and converted into G-code printing instructions.
[0042] (5) Insert the GNP / PLA filament into the feed port of the 3D printer, set the printing parameters, and start printing. The printer needle diameter is 0.4 mm, the printing speed is 30 mm / s, the needle temperature is 200℃, and the print bed temperature is 50℃. After printing, a GNP / PLA composite material with a macroscopic conical hole structure is obtained, which is denoted as conical hole.
[0043] Figure 3 The figures show a printed model and a photograph of the printed conical hole array, wherein (a) shows the surface and cross-section of the conical hole array model, and (b) shows a photograph of the printed GNP / PLA composite material with the conical hole array structure.
[0044] Comparative Example 1
[0045] Comparative Example 1 provides a method for preparing a non-porous GNP / PLA composite material, the specific steps of which are as follows:
[0046] Steps (1)-(3) and step (5) are the same as in Example 1, and step (4) is as follows:
[0047] A 3D modeling software was used on a computer to create a printable material model. The model's dimensions were 34mm × 24mm × 3mm. The model file was exported in STL format and then converted into G-code printing instructions.
[0048] After printing, a GNP / PLA composite material is obtained, which is denoted as non-porous.
[0049] Comparative Example 2
[0050] Comparative Example 2 provides a method for preparing a square semi-porous GNP / PLA composite material, the specific steps of which are as follows:
[0051] Steps (1)-(3) and step (5) are the same as in Example 1, and step (4) is as follows:
[0052] A 3D modeling software was used on a computer to create a printable material model. The model's dimensions were 34mm × 24mm × 3mm. The square holes had a side length of 3.5mm and a height of 1.5mm. The square holes were distributed in a 6×4 matrix, with a center-to-center distance of 4mm between adjacent square holes. The surface and cross-section of the resulting model are shown below. Figure 4 As shown in (a), the model file is exported in STL format and converted into G-code printing instructions.
[0053] After printing, a GNP / PLA composite material with a macroscopic square semi-porous structure is obtained, denoted as square semi-porous. A photograph of the resulting material is shown below. Figure 4 As shown in (b).
[0054] Comparative Example 3
[0055] Comparative Example 3 provides a method for preparing a circular semi-porous GNP / PLA composite material, the specific steps of which are as follows:
[0056] Steps (1)-(3) and step (5) are the same as in Example 1, and step (4) is as follows:
[0057] A 3D modeling software was used on a computer to create a printable material model. The model's dimensions are 34mm × 24mm × 3mm (length × width × height). The radius of the circular holes is 2mm, and their height is 1.5mm. The circular holes are distributed in a 6×4 matrix within the model, with a center-to-center distance of 4.5mm between adjacent holes. The surface and cross-section of the resulting model are shown below. Figure 5 As shown in (a), the model file is exported in STL format and converted into G-code printing instructions.
[0058] After printing, a GNP / PLA composite material with a macroscopic circular semi-pore structure is obtained, denoted as a circular semi-pore. A photograph of the resulting material is shown below. Figure 5 As shown in (b).
[0059] Comparative Example 4
[0060] Comparative Example 4 provides a method for preparing a GNP / PLA composite material with a regular square pyramidal hole, the specific steps of which are as follows:
[0061] Steps (1)-(3) and step (5) are the same as in Example 1, and step (4) is as follows:
[0062] A 3D modeling software was used on a computer to create a printable material model. The model's dimensions are 34mm × 24mm × 3mm. The base of the regular square pyramid holes is 3.5mm long and 3mm high. The holes in the regular square pyramids are distributed in a 6×4 matrix, and the center-to-center distance between adjacent holes is 4mm. The surface and cross-section of the resulting model are shown below. Figure 6 As shown in (a), the model file is exported in STL format and converted into G-code printing instructions.
[0063] After printing, a GNP / PLA composite material with a regular square pyramid hole structure is obtained, denoted as a square pyramid hole. A photograph of the resulting product is shown below. Figure 6 As shown in (b).
[0064] Comparative Example 5
[0065] Comparative Example 5 provides a method for preparing a macroscopic square through-hole structure GNP / PLA composite material, the specific steps of which are as follows:
[0066] Steps (1)-(3) and step (5) are the same as in Example 1, and step (4) is as follows:
[0067] A 3D modeling software was used on a computer to create a printable material model. The model's dimensions are 34mm × 24mm × 3mm. The square holes have a side length of 3.5mm and a height of 3mm. The square holes are distributed in a 6×4 matrix, with a center-to-center distance of 4mm between adjacent square holes. The surface and cross-section of the resulting model are shown below. Figure 7 As shown in (a), the model file is exported in STL format and converted into G-code printing instructions.
[0068] After printing, a GNP / PLA composite material with a square through-hole structure is obtained, denoted as square through-hole. A photograph of the resulting product is shown below. Figure 7 As shown in (b).
[0069] Comparative Example 6
[0070] Comparative Example 6 provides a method for preparing a macroscopic circular through-hole structure GNP / PLA composite material, the specific steps of which are as follows:
[0071] Steps (1)-(3) and step (5) are the same as in Example 1, and step (4) is as follows:
[0072] A 3D modeling software was used on a computer to create a printable material model. The model's dimensions are 34mm × 24mm × 3mm. The radius of the circular holes is 2mm, and their height is 3mm. The circular holes are distributed in a 6×4 matrix within the model, with a center-to-center distance of 4.5mm between adjacent holes. The surface and cross-section of the resulting model are shown below. Figure 8 As shown in (a), the model file is exported in STL format and converted into G-code printing instructions.
[0073] After printing, a GNP / PLA composite material with a macroscopic circular hole structure is obtained, denoted as a circular through hole. A photograph of the resulting material is shown below. Figure 8 As shown in (b).
[0074] Test Example 1
[0075] The scattering parameters (SL) of macroporous GNP / PLA composite materials prepared by the methods shown in all examples and comparative examples in the X-band (8.2–12.4 GHz) were analyzed using a vector network analyzer (P5004A, Agilent). 11 S 22 S 12 S 21 The tests were conducted. The total electromagnetic shielding efficiency (SE) and absorption loss (SE) were measured. A ), reflection loss (SE) R The absorption coefficient (A), reflection coefficient (T), and projection coefficient (T) can be calculated using the following formulas:
[0076] T=|S 12 |2 =|S 21 | 2 (1)
[0077] R=|S 11 | 2 =|S 22 | 2 (2)
[0078] A = 1 – R – T (3)
[0079] SE R =-10lg(1–R) (4)
[0080] SE A =-10lg[(T / (1–R)] (5)
[0081] SE=SE R +SE A (6)
[0082] The sample's performance in the X-band SE was obtained through testing and calculation. Figure 9 As shown in the left-middle figure, the non-porous composite material has the lowest SE value, with an average SE of 25.4 dB in this wavelength band. With the introduction of porous structures, the SE values of all GNP / PLA composite materials increased, indicating that macroscopic porous structures contribute to improved electromagnetic shielding performance. Among them, the conical porous composite material exhibited the best shielding performance, with an average SE of 54.4 dB, an increase of 114.2% compared to the non-porous composite material. SE values for each sample are shown below. A and SE R Comparison chart as follows Figure 9 The figure in the middle shows that the SE in composite materials mainly comes from SE. A The contribution indicates that CNT / PLA can dissipate the electromagnetic energy incident into the material. Figure 9 The right-middle figure shows a comparison of the A, R, and T values of the samples. The non-porous composite material has the highest R value and the lowest A value, indicating that this material is primarily reflective. After introducing a porous structure, the R value of the composite material decreases while the A value increases. Among them, the conical porous composite material achieves an A value of 0.7, demonstrating its superior absorption performance. This high absorption performance stems from the fact that the conical porous structure reduces the reflection of electromagnetic waves on the surface, allowing them to smoothly enter the interior of the material. Furthermore, due to the conical hole's wider top and narrower bottom structure, multiple reflections occur within the material, increasing the interaction between the composite material and electromagnetic waves, thereby enhancing its absorption performance.
[0083] While some embodiments of the present general inventive concept have been shown and described, those skilled in the art will understand that changes may be made to these embodiments without departing from the principles and spirit of the present general inventive concept, the scope of which is defined by the claims and their equivalents.
Claims
1. A method for preparing an electromagnetic shielding material with a macroscopic conical aperture array structure, characterized in that, The preparation method includes the following steps: S1. Add graphene nanosheets and polylactic acid particles to dichloromethane and stir with a magnetic stirrer until the polylactic acid is completely dissolved to obtain a graphene composite dispersion; S2. Place the graphene composite dispersion in a fume hood and allow it to dry naturally at room temperature. After the dichloromethane solvent has completely evaporated, a graphene / polylactic acid composite material is obtained. S3. The obtained graphene / polylactic acid composite material is shredded and fed into a benchtop extruder, and composite filaments for 3D printing are extruded by melt spinning. S4. Create a model for 3D printing on a computer, feed the composite filament into the 3D printer, and use the computer to control the 3D printer to process the electromagnetic shielding material with a macroscopic conical hole array structure.
2. The preparation method according to claim 1, characterized in that, In step S1, the mass ratio of graphene to polylactic acid is 5:95 to 15:85, and the mass ratio of solid material to dichloromethane is 1:4 to 1:
10. The solid material is graphene and polylactic acid.
3. The preparation method according to claim 1, characterized in that, In step S3, the barrel temperature of the benchtop extruder is 195°C, the curing temperature is room temperature, and the extruded fiber diameter is 1.75 mm.
4. The preparation method according to claim 1, characterized in that, In step S4, a 3D modeling software is used on a computer to create a model of the printing material. The conical holes are at the same height as the printing material model, with a base radius of 0.5~3mm and a center-to-center distance of 4~5mm between adjacent conical holes.
5. The preparation method according to claim 1, characterized in that, In step S4, the printer needle diameter is 0.4mm, the printing speed is 30mm / s, the needle temperature is 200℃, and the print bed temperature is 50℃.
6. An electromagnetic shielding material with a macroscopic conical hole array structure prepared by the preparation method of any one of claims 1-5.
7. The application of the electromagnetic shielding material with a macroscopic conical hole array structure as described in claim 6 in electromagnetic shielding.