Room-temperature self-repairing electromagnetic shielding composite material based on thermosetting plastic and preparation method and application thereof
By preparing the thermosetting plastic precursor and the conductive filler to form an electromagnetic shielding composite material with self-healing ability, it solves the damage problem of the thermosetting plastic electromagnetic shielding material during use, realizes the self-repair and performance maintenance of the material, and is suitable for multiple application fields.
Patent Information
- Application Number
- CN202510343347.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-21
- Publication Date
- 2025-06-06
AI Technical Summary
The existing electromagnetic shielding composite materials based on thermoset plastics are prone to microcracks due to factors such as aging or overload during use, resulting in a decrease in mechanical properties and electromagnetic shielding properties, and the existing self-repair materials have poor heat resistance and mechanical properties.
The thermosetting plastic precursor is prepared by reacting N,N’-bis(acryloyl) monomers with diamine monomers, and is compounded with conductive fillers such as graphene, carbon nanotubes, etc. to form a room temperature self-healing electromagnetic shielding composite material with hyperbranched structure.
It realizes the self-healing performance of the material at room temperature, maintains good size and mechanical stability, and has excellent conductivity and electromagnetic shielding performance, and is suitable for military industry, communication technology and electronic equipment and other fields.
Smart Images
Figure CN120098254A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of polymer conductive composite materials, and in particular relates to a room temperature self-repairing electromagnetic shielding composite material based on thermosetting plastics, and a preparation method and application thereof. Background Art
[0002] The electromagnetic shielding materials that have been developed so far mainly include: metals, ceramics and conductive polymer composites. Among them, conductive polymer materials prepared by carbon material filling polymers have received extensive attention and research due to their advantages such as light weight, high strength, high conductivity and easy processing. Compared with thermoplastic electromagnetic shielding composites, thermosetting electromagnetic shielding composites have great practical value due to their good dimensional stability and mechanical stability.
[0003] However, existing electromagnetic shielding composite materials based on thermosetting plastics will inevitably suffer damage and destruction during use due to factors such as aging and overload, resulting in internal microcracks, which will further develop into cracks visible to the naked eye, causing a significant decrease in the mechanical properties and other properties of the material, and ultimately macroscopic failure. In order to extend the service life of polymer electromagnetic shielding composite materials, the industry has conducted a lot of research on self-healing electromagnetic shielding composite materials, mainly using rubber or elastomer as the matrix material, but rubber or elastomer materials have poor heat resistance and mechanical properties.
[0004] Therefore, it is necessary to develop a room temperature self-healing electromagnetic shielding composite material based on thermosetting plastics so that it has good dimensional stability, mechanical stability and room temperature self-healing performance to meet more application fields. Summary of the invention
[0005] In order to solve the above problems existing in the prior art, the object of the present invention is to provide a room temperature self-healing electromagnetic shielding composite material based on thermosetting plastics, and a preparation method and use thereof.
[0006] In order to achieve the above object, the present invention adopts the following technical solution:
[0007] The present invention provides a thermosetting plastic precursor, which is prepared by reacting an N,N'-bis(acryl) monomer with a diamine monomer, wherein the molar ratio of the N,N'-bis(acryl) monomer to the diamine monomer is 1:(0.1-3), and at least one of the N,N'-bis(acryl) monomer and the diamine monomer contains the following structure:
[0008] Furthermore, the molar ratio of the N,N'-bis(acryloyl) monomer to the diamine monomer is 1:(1-1.125).
[0009] Further, the N,N'-bis(acryl) monomer is N,N'-bis(acryl)cystamine, and the diamine monomer is at least one of ethylenediamine, propylenediamine, butylenediamine, pentanediamine, hexamethylenediamine, and p-phenylenediamine;
[0010] Alternatively, the N,N'-bis(acryl) monomer is at least one of N,N'-methylenebisacrylamide and N,N'-methylenebismethylacrylamine, and the diamine monomer is cystamine.
[0011] The present invention also provides a method for preparing the thermosetting plastic precursor. The method comprises preparing a mixed solution of N,N'-bis(acryloyl) monomers and diamine monomers, reacting, precipitating and washing to obtain the thermosetting plastic precursor.
[0012] Furthermore, the solvent of the mixed solution is a mixed solvent of alcohol and water, the volume ratio of the alcohol to water is (0.5-5):1, and the alcohol is methanol; the reaction temperature is 10-60°C; and the reaction time is 24-72h.
[0013] Furthermore, the volume ratio of the alcohol to water is 2:1; the reaction temperature is 30-40° C.; and the reaction time is 48 hours.
[0014] The present invention also provides a room temperature self-healing electromagnetic shielding composite material based on thermosetting plastics, wherein the room temperature self-healing electromagnetic shielding composite material is prepared by reacting a conductive filler with a thermosetting plastic precursor; the mass ratio of the conductive filler to the thermosetting plastic precursor is (0.1-50):100.
[0015] Furthermore, the mass ratio of the conductive filler to the thermosetting plastic precursor is (1-20):100; the conductive filler is at least one of graphene, carbon nanotubes, carbon black, Mexene, iron powder, copper powder, and silver powder.
[0016] The present invention also provides a method for preparing the above-mentioned room temperature self-repairing electromagnetic shielding composite material, which comprises preparing a mixed solution of a conductive filler and a thermosetting plastic precursor, reacting, removing the solvent, and drying to obtain a room temperature self-repairing electromagnetic shielding composite material based on thermosetting plastic.
[0017] Furthermore, the solvent of the mixed solution is alcohol or water; the alcohol is methanol, ethanol or isopropanol.
[0018] The present invention also provides application of the room temperature self-repairing electromagnetic shielding composite material in the fields of self-repairing materials and electromagnetic shielding materials.
[0019] The present invention has achieved the following beneficial effects:
[0020] The present invention provides a room temperature self-healing electromagnetic shielding composite material based on thermosetting plastics. First, a thermosetting plastic precursor with a hyperbranched structure is prepared, and then an inorganic conductive filler is compounded with the thermosetting plastic precursor. The composite material has excellent room temperature self-healing performance, good dimensional stability and mechanical stability, and also has good conductivity, electromagnetic shielding performance and excellent mechanical properties. The room temperature self-healing electromagnetic shielding composite material of the present invention can not only realize room temperature self-healing of mechanical properties, but also realize room temperature self-healing of electromagnetic shielding performance, and has broad application prospects in the fields of military industry, communication technology, electronic equipment, sensors, etc.
[0021] Obviously, according to the above contents of the present invention, in accordance with common technical knowledge and customary means in the art, without departing from the above basic technical ideas of the present invention, other various forms of modification, replacement or change may be made.
[0022] The above contents of the present invention are further described in detail below through specific implementation methods in the form of embodiments. However, this should not be understood as the scope of the above subject matter of the present invention being limited to the following examples. All technologies realized based on the above contents of the present invention belong to the scope of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] Figure 1 (a) The room temperature self-repairing diagram of the mechanical properties of the electromagnetic shielding composite material A prepared in Example 1 under no pressure and (b) The room temperature self-repairing diagram of the electromagnetic shielding properties of the electromagnetic shielding composite material C prepared in Example 3.
[0024] Figure 2 Room temperature self-healing diagram of the mechanical properties of the electromagnetic shielding composite material B prepared in Example 2 under (a) no pressure and (b) pressure.
[0025] Figure 3 These are the tensile stress-strain curves of the electromagnetic shielding composite materials D, E, and F prepared in Examples 4, 5, and 6. DETAILED DESCRIPTION
[0026] The raw materials and equipment used in the present invention are all known products, which are obtained by purchasing commercially available products.
[0027] The following experiments without any explanation of temperature are reactions under normal temperature conditions, where normal temperature is room temperature, which is 25-30°C.
[0028] The following test methods were used:
[0029] 1. Electromagnetic shielding performance and self-repairing performance test
[0030] The electromagnetic shielding performance and self-healing performance of the sample were tested by VNA AgilentN5230A vector network analyzer.
[0031] 2. Mechanical properties and self-healing test
[0032] The self-healing performance of the samples was tested using an Instron 5967 tensile testing machine.
[0033] Example 1: Preparation of room temperature self-healing electromagnetic shielding composite material A based on thermosetting plastic
[0034] (1) Preparation of thermosetting plastic precursor A: N,N'-bis(acryloyl)cystamine was added to a mixed solvent (methanol and deionized water, volume ratio of 2:1) at 30°C, and stirred to obtain a mixed solution A (the molar volume ratio of N,N'-bis(acryloyl)cystamine to the mixed solvent was 1 mol:3 L); ethylenediamine monomer was dissolved in a mixed solvent (methanol and deionized water, volume ratio of 2:1) to obtain a mixed solution B (the molar volume ratio of ethylenediamine monomer to the mixed solvent was 3 mol:1 L); mixed solution A and mixed solution B were mixed in a certain ratio (the molar ratio of N,N'-bis(acryloyl)cystamine to ethylenediamine was 1:1.1), reacted at 30°C for 48 h, and obtained a thermosetting plastic precursor A after precipitation and washing.
[0035] (2) Preparation of room temperature self-healing electromagnetic shielding composite material A based on thermosetting plastic: 1 g of graphene conductive filler was added to methanol solvent (the mass ratio of graphene conductive filler to methanol solvent was 1:100) and ultrasonically dispersed for 2 hours to obtain a graphene conductive dispersion; the thermosetting plastic precursor A obtained in step (1) of this embodiment was added to methanol solvent (the mass ratio of thermosetting plastic precursor A to methanol solvent was 1:40) and dissolved to obtain a thermosetting plastic precursor A polymer solution; the graphene conductive dispersion was added to the thermosetting plastic precursor A polymer solution (the mass ratio of graphene conductive filler to thermosetting plastic precursor A was 2.5:100) and ultrasonically dispersed at room temperature for 3 hours, and then the solvent was removed. The sample after the solvent was removed was dried at 60°C to obtain a preliminary sample A; the preliminary sample A was prepared into a room temperature self-healing electromagnetic shielding composite material A based on thermosetting plastic using a flat vulcanizer.
[0036] Example 2: Preparation of room temperature self-healing electromagnetic shielding composite material B based on thermosetting plastic
[0037] (1) Preparation of thermosetting plastic precursor B: Referring to the preparation method of thermosetting plastic precursor A in step (1) of Example 1, the only difference is that the ethylenediamine monomer in the preparation method of thermosetting plastic precursor A is replaced with butylene diamine monomer to obtain thermosetting plastic precursor B.
[0038] (2) Preparation of room temperature self-healing electromagnetic shielding composite material B based on thermosetting plastic: 1 g of carbon nanotube conductive filler is added to methanol solvent (the mass ratio of carbon nanotube conductive filler to methanol solvent is 1:100) and ultrasonically dispersed for 2 hours to obtain a carbon nanotube conductive dispersion; the thermosetting plastic precursor B obtained in step (1) of this embodiment is added to methanol solvent (the mass ratio of thermosetting plastic precursor B to methanol solvent is 1:40) and dissolved to obtain a thermosetting plastic precursor B polymer solution; the carbon nanotube conductive dispersion is added to the thermosetting plastic precursor B polymer solution (the mass ratio of carbon nanotube conductive filler to thermosetting plastic precursor B is 5:100) and ultrasonically dispersed at room temperature for 3 hours, and then the solvent is removed. The sample after the solvent is removed is dried at 60°C to obtain a preliminary sample B; the preliminary sample B is prepared into a room temperature self-healing electromagnetic shielding composite material B based on thermosetting plastic using a flat vulcanizer.
[0039] Example 3: Preparation of room temperature self-healing electromagnetic shielding composite material C based on thermosetting plastic
[0040] (1) Preparation of thermosetting plastic precursor C: Referring to the preparation method of thermosetting plastic precursor A, the only difference is that the ethylenediamine monomer in the preparation method of thermosetting plastic precursor A is replaced by hexamethylenediamine monomer to obtain thermosetting plastic precursor C.
[0041] (2) Preparation of room temperature self-healing electromagnetic shielding composite material C based on thermosetting plastic: Add 1 g of carbon black conductive filler into methanol solvent (the mass ratio of carbon black conductive filler to methanol solvent is 1:100) and ultrasonically disperse for 3 hours to obtain a carbon black conductive dispersion; add the thermosetting plastic precursor C obtained in step (1) of this embodiment into methanol solvent (the mass ratio of thermosetting plastic precursor C to methanol solvent is 1:40) to dissolve to obtain a thermosetting plastic precursor C polymer solution; add the carbon black conductive dispersion into the thermosetting plastic precursor C polymer solution (the mass ratio of carbon black conductive filler to thermosetting plastic precursor C is 5:100) and ultrasonically disperse at room temperature for 5 hours, remove the solvent, and then dry the sample after the solvent is removed at 60°C to obtain a preliminary sample C; use a flat plate vulcanizer to prepare the preliminary sample C into a room temperature self-healing electromagnetic shielding composite material C based on thermosetting plastic.
[0042] Example 4: Preparation of room temperature self-healing electromagnetic shielding composite material D based on thermosetting plastic
[0043] (1) Preparation of thermosetting plastic precursor D: N,N'-methylenebisacrylamide was added to a mixed solvent (methanol to deionized water volume ratio of 2:1) at 30°C, and stirred to obtain a mixed solution A1 (N,N'-methylenebisacrylamide to mixed solvent molar volume ratio of 1 mol:3 L); cystamine monomer was dissolved in a mixed solvent (methanol to deionized water volume ratio of 2:1) to obtain a mixed solution B1 (cystamine monomer to mixed solvent molar volume ratio of 3 mol:1 L); mixed solution A1 and mixed solution B1 were mixed in a certain ratio (N,N'-methylenebisacrylamide to cystamine molar ratio of 1:1.125), reacted at 40°C for 48 h, and obtained thermosetting plastic precursor D after precipitation and washing.
[0044] (2) Preparation of room temperature self-healing electromagnetic shielding composite material D based on thermosetting plastic: 1 g of Mexene conductive filler was added to methanol solvent (the mass ratio of Mexene conductive filler to methanol solvent was 1:100) and ultrasonically dispersed for 3 hours to obtain a Mexene conductive dispersion; the thermosetting plastic precursor D obtained in step (1) of this embodiment was added to methanol solvent (the mass ratio of thermosetting plastic precursor D to methanol solvent was 1:50) and dissolved to obtain a thermosetting plastic precursor D polymer solution; the Mexene conductive dispersion was added to the thermosetting plastic precursor D polymer solution (the mass ratio of Mexene conductive filler to thermosetting plastic precursor D was 2.5:100) and ultrasonically dispersed at room temperature for 5 hours, and then the solvent was removed. The sample after the solvent was removed was dried at 60°C to obtain a preliminary sample D; the preliminary sample D was prepared into a room temperature self-healing electromagnetic shielding composite material D based on thermosetting plastic using a flat vulcanizer.
[0045] Example 5: Preparation of room temperature self-healing electromagnetic shielding composite material E based on thermosetting plastic
[0046] (1) Preparation of thermosetting plastic precursor E: Referring to the preparation method of thermosetting plastic precursor A, the only difference is that the ethylenediamine monomer in the preparation method of thermosetting plastic precursor A is replaced with p-phenylenediamine monomer to obtain thermosetting plastic precursor E.
[0047] (2) Preparation of room temperature self-healing electromagnetic shielding composite material E based on thermosetting plastic: 0.5 g carbon nanotubes and 0.5 g graphene conductive filler were added to methanol solvent (the mass ratio of carbon nanotubes and graphene conductive filler to methanol solvent was 0.5:0.5:100) and ultrasonically dispersed for 2 h to obtain a carbon nanotube and graphene conductive dispersion; the thermosetting plastic precursor E obtained in step (1) of this embodiment was added to methanol solvent (the mass ratio of thermosetting plastic precursor E to methanol solvent was 1:50) and dissolved. The carbon nanotube and graphene conductive dispersion is added to the thermosetting plastic precursor E polymer solution (the mass ratio of carbon nanotube and graphene conductive filler to thermosetting plastic precursor E is 2.5:2.5:100), and ultrasonically dispersed at room temperature for 3 hours, and then the solvent is removed. The sample after the solvent is removed is dried at 60°C to obtain a preliminary sample E. The preliminary sample E is prepared into a room temperature self-healing electromagnetic shielding composite material E based on thermosetting plastic using a flat vulcanizer.
[0048] Example 6: Preparation of room temperature self-healing electromagnetic shielding composite material F based on thermosetting plastic
[0049] (1) Preparation of thermosetting plastic precursor F: N,N'-methylenebis(methylpropene)amine was added to a mixed solvent (methanol to deionized water volume ratio of 2:1) at 35°C, and stirred to obtain a mixed solution A2 (N,N'-methylenebis(methylpropene)amine to mixed solvent molar volume ratio of 1 mol:3 L); cystamine monomer was dissolved in a mixed solvent (methanol to deionized water volume ratio of 2:1) to obtain a mixed solution B2 (cystamine monomer to mixed solvent molar volume ratio of 2.5 mol:1 L); mixed solution A2 and mixed solution B2 were mixed in a certain ratio (N,N'-methylenebis(methylpropene)amine to cystamine molar ratio of 1:0.875), reacted at 40°C for 48 h, and obtained a thermosetting plastic precursor F after precipitation and washing.
[0050] (2) Preparation of room temperature self-healing electromagnetic shielding composite material F based on thermosetting plastic: 0.25 g of carbon nanotubes and 0.75 g of graphene conductive filler were added to methanol solvent (the mass ratio of carbon nanotubes and graphene conductive filler to methanol solvent was 0.25:0.75:100) and ultrasonically dispersed for 2 h to obtain a carbon nanotube and graphene conductive dispersion; the thermosetting plastic precursor F obtained in step (1) of this embodiment was added to methanol solvent (the mass ratio of thermosetting plastic precursor F to methanol solvent was 1:50) and the mixture was stirred for 2 h. The carbon nanotube and graphene conductive dispersion is added to the thermosetting plastic precursor F polymer solution (the mass ratio of carbon nanotube and graphene conductive filler to thermosetting plastic precursor F is 1.25:3.75:100), and ultrasonically dispersed at room temperature for 3 hours, and then the solvent is removed. The sample after the solvent is removed is dried at 60°C to obtain a preliminary sample F. The preliminary sample F is prepared into a room temperature self-healing electromagnetic shielding composite material F based on thermosetting plastic using a flat vulcanizer.
[0051] Example 7: Preparation of room temperature self-healing electromagnetic shielding composite material G based on thermosetting plastic
[0052] (1) Preparation of thermosetting plastic precursor G: Referring to the preparation method of thermosetting plastic precursor F, the only difference is that the molar ratio of N,N'-methylenebis(methylpropenylamine) to cystamine in the preparation method of thermosetting plastic precursor F is replaced with 1:1 to obtain thermosetting plastic precursor G.
[0053] (2) Preparation of room temperature self-healing electromagnetic shielding composite material G based on thermosetting plastic: 1 g of carbon nanotube conductive filler is added to methanol solvent (the mass ratio of carbon nanotube conductive filler to methanol solvent is 1:100) and ultrasonically dispersed for 2 hours to obtain a carbon nanotube conductive dispersion; the thermosetting plastic precursor G obtained in step (1) of this embodiment is added to methanol solvent (the mass ratio of thermosetting plastic precursor G to methanol solvent is 1:50) to dissolve to obtain a thermosetting plastic precursor G polymer solution; the carbon nanotube conductive dispersion is added to the thermosetting plastic precursor G polymer solution (the mass ratio of carbon nanotube conductive filler to thermosetting plastic precursor G is 10:100) and ultrasonically dispersed at room temperature for 3 hours, and then the solvent is removed. The sample after the solvent is removed is dried at 60°C to obtain a preliminary sample G; the preliminary sample G is prepared into a room temperature self-healing electromagnetic shielding composite material G based on thermosetting plastic using a flat vulcanizer.
[0054] Example 8: Preparation of room temperature self-healing electromagnetic shielding composite material H based on thermosetting plastic
[0055] (1) Preparation of thermosetting plastic precursor H: Referring to the preparation method of thermosetting plastic precursor A, the only difference is that the ethylenediamine monomer in the preparation method of thermosetting plastic precursor A is replaced by pentanediamine monomer, and the reaction temperature after mixing the mixed solution A and the mixed solution B is changed from 30°C to 40°C, so as to obtain thermosetting plastic precursor H.
[0056] (2) Preparation of room temperature self-healing electromagnetic shielding composite material H based on thermosetting plastic: 1 g of graphene conductive filler was added to methanol solvent (the mass ratio of graphene conductive filler to methanol solvent was 1:100) and ultrasonically dispersed for 2 hours to obtain a graphene conductive dispersion; the thermosetting plastic precursor H obtained in step (1) of this embodiment was added to methanol solvent (the mass ratio of thermosetting plastic precursor H to methanol solvent was 1:50) and dissolved to obtain a thermosetting plastic precursor H polymer solution; the graphene conductive dispersion was added to the thermosetting plastic precursor H polymer solution (the mass ratio of graphene conductive filler to thermosetting plastic precursor H was 1:100) and ultrasonically dispersed at room temperature for 3 hours, and then the solvent was removed. The sample after the solvent was removed was dried at 60°C to obtain a preliminary sample H; the preliminary sample H was prepared into a room temperature self-healing electromagnetic shielding composite material H based on thermosetting plastic using a flat vulcanizer.
[0057] Example 9: Preparation of room temperature self-healing electromagnetic shielding composite material I based on thermosetting plastic
[0058] (1) Referring to the preparation method of thermosetting plastic precursor B in step (1) of Example 2, a thermosetting plastic precursor B is obtained;
[0059] (2) Preparation of room temperature self-healing electromagnetic shielding composite material I based on thermosetting plastic: 1 g of graphene conductive filler was added to methanol solvent (the mass ratio of graphene conductive filler to methanol solvent was 1:100) and ultrasonically dispersed for 2 hours to obtain a graphene conductive dispersion; the thermosetting plastic precursor B obtained in step (1) of this embodiment was added to methanol solvent (the mass ratio of thermosetting plastic precursor B to methanol solvent was 1:40) and dissolved to obtain a thermosetting plastic precursor B polymer solution; the graphene conductive dispersion was added to the thermosetting plastic precursor B polymer solution (the mass ratio of graphene conductive filler to thermosetting plastic precursor B was 20:100) and ultrasonically dispersed at room temperature for 3 hours, and then the solvent was removed. The sample after the solvent was removed was dried at 60°C to obtain a preliminary sample I; the preliminary sample I was prepared into a room temperature self-healing electromagnetic shielding composite material I based on thermosetting plastic using a flat vulcanizer.
[0060] Example 10: Preparation of room temperature self-healing electromagnetic shielding composite material J based on thermosetting plastic
[0061] (1) Referring to the preparation method of thermosetting plastic precursor C in step (1) of Example 3, a thermosetting plastic precursor C is obtained.
[0062] (2) Preparation of room temperature self-healing electromagnetic shielding composite material J based on thermosetting plastic: 1 g of carbon nanotube conductive filler was added to methanol solvent (the mass ratio of carbon nanotube conductive filler to methanol solvent was 1:100) and ultrasonically dispersed for 2 hours to obtain a carbon nanotube conductive dispersion; the thermosetting plastic precursor C obtained in step (1) of this embodiment was added to methanol solvent (the mass ratio of thermosetting plastic precursor C to methanol solvent was 1:40) and dissolved to obtain a thermosetting plastic precursor C polymer solution; the carbon nanotube conductive dispersion was added to the thermosetting plastic precursor C polymer solution (the mass ratio of carbon nanotube conductive filler to thermosetting plastic precursor C was 7.5:100) and ultrasonically dispersed at room temperature for 3 hours, and then the solvent was removed. The sample after the solvent was removed was dried at 60°C to obtain a preliminary sample J; the preliminary sample J was prepared into a room temperature self-healing electromagnetic shielding composite material J based on thermosetting plastic using a flat vulcanizer.
[0063] The beneficial effects of the present invention are demonstrated by experimental examples below.
[0064] Experimental Example 1: Mechanical properties of room temperature self-healing electromagnetic shielding composite materials based on thermosetting plastics
[0065] The self-healing performance of the sample mechanical properties was tested by an Instron 5967 tensile testing machine. The electromagnetic shielding composite material was prepared into a size of 35×2×1mm 3 The dumbbell-shaped tensile specimens were cut in the middle and then the two fresh sections were repaired at room temperature for 48 h.
[0066] The electromagnetic shielding composite material A prepared in Example 1 was tested for its self-repairing performance. The results are as follows: Figure 1 As shown in a, under no pressure, at 25℃ for 48h, the strength of electromagnetic shielding composite material A can be repaired to 16.7MPa, and the repair efficiency is as high as 70.8%;
[0067] The electromagnetic shielding composite material B prepared in Example 2 was tested for its self-repairing performance. The results are as follows: Figure 2 As shown, Figure 2 a is the case of repair at 25℃ for 48h without pressure. The strength of electromagnetic shielding composite material B is 10.1MPa, and the repair efficiency is only 30.8%; Figure 2 b: At 20°C and 40N pressure, the strength of the material was restored to 28.73N after 60 minutes of repair, and the repair efficiency reached 98.5%.
[0068] from Figure 1 and Figure 2It can be found that this room temperature self-repairing electromagnetic shielding composite material based on thermosetting plastic can be partially repaired without pressure, and the material can be quickly repaired under external force. Compared with the electromagnetic shielding composite material B prepared in Example 2, the electromagnetic shielding composite material A prepared in Example 1 has better mechanical properties and self-repairing properties.
[0069] Experimental Example 2: Self-repair of electromagnetic shielding performance of room temperature self-repairing electromagnetic shielding composite materials based on thermosetting plastics
[0070] The electromagnetic shielding performance and self-healing performance of the sample were tested by VNAAgilent N5230A vector network analyzer. The electromagnetic shielding composite material was prepared into a size of 35×2×1mm 3 The dumbbell-shaped tensile specimen was cut in half, and then the two fresh sections were repaired at room temperature for 48 hours. The electromagnetic shielding performance self-repairing performance test of the electromagnetic shielding composite material C prepared in Example 3 was performed. The results are shown in FIG. Figure 1 As shown in b, after the strip was cut and repaired at 25°C for 48 hours, the electromagnetic shielding effectiveness (EMI SE) value of the strip was 21.3 dB, and the repair efficiency was as high as 95.5% compared with the original strip performance (22.3 dB). This shows that the conductive network and electromagnetic shielding performance of this room temperature self-healing electromagnetic shielding composite material based on thermosetting plastic can be repaired at room temperature.
[0071] Experimental Example 3: Mechanical properties of room temperature self-healing electromagnetic shielding composite materials based on thermosetting plastics
[0072] The mechanical properties of the electromagnetic shielding composite material were tested using an Instron 5967 tensile testing machine. The electromagnetic shielding composite material was prepared into a size of 35×2×1mm 3 The dumbbell-shaped tensile specimens were tested for mechanical properties at room temperature at a tensile rate of 10 mm / min.
[0073] The tensile stress-strain curve test results of the electromagnetic shielding composite material D, E, and F splines prepared in Examples 4, 5, and 6 are as follows: Figure 3 As shown, the tensile strengths of electromagnetic shielding composite materials D, E, and F splines are 24.04MPa, 32.65MPa, and 43.88MPa, respectively. All three samples show excellent mechanical properties.
[0074] In summary, the present invention provides a room temperature self-healing electromagnetic shielding composite material based on thermosetting plastics. First, a thermosetting plastic precursor with a hyperbranched structure is prepared, and then an inorganic conductive filler is compounded with the thermosetting plastic precursor. The composite material has excellent room temperature self-healing performance, good dimensional stability and mechanical stability, as well as good conductivity, electromagnetic shielding performance and excellent mechanical properties. The room temperature self-healing electromagnetic shielding composite material of the present invention can not only realize room temperature self-healing of mechanical properties, but also realize room temperature self-healing of electromagnetic shielding performance, and has broad application prospects in the fields of military industry, communication technology, electronic equipment, sensors, etc.
Claims
1. A thermosetting plastic precursor, characterized in that: The thermosetting plastic precursor is prepared by reacting N,N'-bis(acryl) monomers with diamine monomers, the molar ratio of N,N'-bis(acryl) monomers to diamine monomers is 1:(0.1-3), and at least one of the N,N'-bis(acryl) monomers and the diamine monomers contains the following structure:
2. The thermosetting plastic precursor according to claim 1, characterized in that: The molar ratio of the N,N'-bis(acryloyl) monomer to the diamine monomer is 1:(1-1.125).
3. The thermosetting plastic precursor according to claim 1 or 2, characterized in that: The N,N'-bis(acryl) monomer is N,N'-bis(acryl)cystamine, and the diamine monomer is at least one of ethylenediamine, propylenediamine, butylenediamine, pentanediamine, hexamethylenediamine, and p-phenylenediamine; Alternatively, the N,N'-bis(acryl) monomer is at least one of N,N'-methylenebisacrylamide and N,N'-methylenebismethylacrylamine, and the diamine monomer is cystamine.
4. The method for preparing a thermosetting plastic precursor according to any one of claims 1 to 3, characterized in that: The preparation method comprises the steps of preparing a mixed solution of N,N'-bis(acryloyl) monomers and diamine monomers, reacting the monomers, and obtaining a thermosetting plastic precursor through precipitation and washing.
5. The preparation method according to claim 4, characterized in that: The solvent of the mixed solution is a mixed solvent of alcohol and water, the volume ratio of the alcohol to water is (0.5-5):1, and the alcohol is methanol; the reaction temperature is 10-60°C; the reaction time is 24-72h; preferably, the volume ratio of the alcohol to water is 2:1; the reaction temperature is 30-40°C; and the reaction time is 48h.
6. A room temperature self-repairing electromagnetic shielding composite material based on thermosetting plastic, characterized in that: The room temperature self-repairing electromagnetic shielding composite material is prepared by reacting a conductive filler with a thermosetting plastic precursor; the mass ratio of the conductive filler to the thermosetting plastic precursor is (0.1-50):
100.
7. The room temperature self-repairing electromagnetic shielding composite material according to claim 6, characterized in that: The mass ratio of the conductive filler to the thermosetting plastic precursor is (1-20):100; the conductive filler is at least one of graphene, carbon nanotubes, carbon black, Mexene, iron powder, copper powder, and silver powder.
8. The method for preparing the room temperature self-repairing electromagnetic shielding composite material according to claim 6 or 7, characterized in that: The preparation method comprises the steps of preparing a mixed solution of a conductive filler and a thermosetting plastic precursor, reacting, removing the solvent, and drying to obtain a room temperature self-repairing electromagnetic shielding composite material based on the thermosetting plastic.
9. The preparation method according to claim 8, characterized in that: The solvent of the mixed solution is alcohol or water; the alcohol is methanol, ethanol or isopropanol.
10. Application of the room temperature self-repairing electromagnetic shielding composite material according to claim 6 or 7 in the field of self-repairing materials and electromagnetic shielding materials.