Corrosion-resistant high-strength sandwich-structure electromagnetic shielding composite material and preparation method thereof

Abstract

The invention provides a corrosion-resistant high-strength sandwich-structure electromagnetic shielding composite material and a preparation method thereof, and the preparation method comprises the following steps: synthesizing a phenylacetylene-terminated soluble crystalline polyether-ether-ketone precursor, and introducing a phenylacetylene group to the surface of a filler through electrochemical grafting. Then, the precursor is dissolved in a solvent, filler is fully infiltrated in the solvent, acid treatment is performed after the solvent is dried, the soluble precursor is converted into phenylacetylene-terminated crystalline polyether-ether-ketone, and finally, the corrosion-resistant and high-strength electromagnetic shielding composite material with the sandwich structure is constructed through hot pressing. The material has the following advantages that rapid functionalization of the filler can be achieved through electrochemical grafting, and the conductive film prepared in advance is beneficial to formation of a continuous conductive network; the interface bonding force between the filler and the polymer is enhanced through thermal crosslinking of phenylacetylene groups, and the mechanical property of the material is remarkably improved, so that the problems of strength reduction, poor thermal stability, easiness in corrosion and the like in a traditional high-conductivity material are effectively solved.

Description

Technical Field

[0001] The present invention relates to electromagnetic shielding materials, and in particular to a corrosion-resistant high-strength sandwich structure electromagnetic shielding composite material and a preparation method thereof. Background Art

[0002] With the rapid development of 5G technology and smart electronic devices, the electromagnetic pollution it brings is becoming increasingly serious. This will not only interfere with the normal operation of precision instruments and communication equipment, but also make human health difficult to protect. Therefore, research on electromagnetic shielding materials is imminent. At present, polymer-based electromagnetic shielding materials have the advantages of light weight, easy processing, and high stability. However, these materials are usually used in environments such as high-intensity vibration, high temperature, or oil and gas corrosion. In such conditions, the application will have an adverse effect on the mechanical and corrosion resistance of the material, resulting in material performance degradation, which will seriously affect the normal operation of the instrument and human health. Therefore, the quality and stability of electromagnetic shielding materials directly affect their application. Therefore, there is an urgent need to develop electromagnetic shielding materials with high electromagnetic shielding performance, high strength, and corrosion resistance.

[0003] Electromagnetic shielding composite materials reported in existing literature typically use cellulose, polyimide, polystyrene, and polyethylene as polymer matrices. However, the electromagnetic shielding, electrical conductivity, thermal stability, solvent resistance, and mechanical properties of these composite materials currently struggle to meet the requirements for high-end applications. Furthermore, existing technologies mix conductive fillers with polymers to improve the electromagnetic shielding and electrical conductivity of the material. However, the lack of interaction between the conductive fillers and the polymers makes them prone to fracture when subjected to external stress, adversely affecting the mechanical properties of the material. Furthermore, limited filler modification leads to severe agglomeration of the conductive fillers, significantly impacting the electrical and mechanical properties. Even when increasing the conductive filler content to improve electrical conductivity, it is difficult to achieve improvements in mechanical properties, corrosion resistance, electrical conductivity, and thermal stability. Therefore, the development of composite materials with high strength, corrosion resistance, high electromagnetic shielding performance, electrical conductivity, and high thermal stability is a pressing technical challenge. Summary of the Invention

[0004] To solve the above technical problems, the present invention provides a corrosion-resistant, high-strength sandwich structure electromagnetic shielding composite material, the preparation method of which comprises the following steps:

[0005] (1) Preparation of soluble crystalline polyetheretherketone precursor terminated with phenylacetylene

[0006] 1,1-bis(4-fluorophenyl)-N-phenylformimine, hydroquinone and anhydrous potassium carbonate are added to a solvent and stirred and mixed, and then reacted at 130-210° C. for 3-15 hours under nitrogen protection, and then cooled to 120-140° C., and then 4-fluoro-4,-(phenylethynyl) benzophenone is added, and then heated to 160-200° C. and reacted for 2-10 hours, and then washed, dried and crushed to obtain a soluble crystalline polyetheretherketone precursor terminated with phenylethynyl. The 1,1-bis(4-fluorophenyl)-N The molar ratio of 1,1-bis(4-fluorophenyl)-N-phenylformimine, hydroquinone, anhydrous potassium carbonate and 4-fluoro-4,-(phenylethynyl)benzophenone is 1-1.1:1-1.5:1.3-1.7:0.25-1.5, the solid content of the 1,1-bis(4-fluorophenyl)-N-phenylformimine and hydroquinone in the solvent is 15-25%, and the solvent is one of sulfolane, diphenyl sulfone or N-methylpyrrolidone. The synthesis route of the phenylethynyl-terminated soluble crystalline polyetheretherketone precursor is as follows:

[0007]

[0008] (2) Preparation of phenylacetylene grafted films

[0009] At 0-5° C., 4-fluoro-4,-(phenylethynyl)benzophenone and nitrosotetrafluoroborate are added to 50-150 ml of acetonitrile in a molar ratio of 1:1-2 and stirred for 20-60 minutes. Then, 0.05-0.2 mmol / L of tetrabutyl tetrafluoroborate is added and stirred for another 20-60 minutes to obtain a mixed solution. Then, a thin film material is immersed in the mixed solution. The thin film material is subjected to cyclic voltammetry at a rate of 0.005-0.3 V / s at a voltage of -1.3 V-2 V for 3-20 cycles. The thin film material is then washed with acetonitrile and water for 3-6 times and then dried to obtain a phenylacetylene-grafted thin film. The thin film material is one of a carbon nanotube film, a graphene film, a MXene film, a silver nanowire film, and a carbon fiber film. The mass ratio of the thin film material to acetonitrile is 1:7000-1:4000.

[0010] (3) the soluble crystalline polyetheretherketone (PEEK) terminated by the phenylacetylene precursor obtained in step (1) is dissolved in a solvent to obtain a polymer solution, and the phenylacetylene grafted film obtained in step (2) is immersed in the polymer solution for 0.5 to 3 hours, and then kept warm at 20 to 60° C. for 6 to 12 hours to obtain a composite material; the mass ratio of the soluble crystalline polyetheretherketone (PEEK) terminated by the phenylacetylene precursor to the solvent is 1:30 to 1000, and the mass ratio of the phenylacetylene grafted film to the soluble crystalline polyetheretherketone (PEEK) terminated by the phenylacetylene precursor is 1:0.1 to 10, and the solvent used is one or any combination of tetrahydrofuran, N-methylpyrrolidone or N,N-dimethylformamide;

[0011] (4) placing the composite material obtained in step (3) in hydrochloric acid having a concentration of 3 to 20 mol / l, heating to 110 to 150° C., and placing for 5 to 15 hours to obtain composite material 1;

[0012] (5) The composite material 1 obtained in step (4) is hot-pressed at 360-420° C. for 0.5-3 h to obtain a corrosion-resistant high-strength sandwich structure electromagnetic shielding composite material, wherein the corrosion-resistant high-strength sandwich structure electromagnetic shielding composite material is a grafted structure; the corrosion-resistant high-strength sandwich structure electromagnetic shielding composite material has excellent electromagnetic shielding performance, ultra-high strength, corrosion resistance, conductivity and thermal stability, and its conductivity is 150-2000 S / cm, the electromagnetic shielding value is between 42-100 dB, and the tensile strength is 115-350 MPa. After corrosion treatment, it still has excellent strength, corrosion resistance, electromagnetic shielding performance, conductivity and thermal stability.

[0013] Furthermore, the corrosion-resistant high-strength sandwich structure electromagnetic shielding composite material has a conductivity of 250 to 1500 S / cm, an electromagnetic shielding value of 46 to 90 dB, and a tensile strength of 120 to 280 MPa.

[0014] Compared with the existing technology, the present invention achieves the following advantages through the coordinated regulation of raw materials, raw material ratios, processes and process parameters: a continuous conductive network is formed through physical and chemical reactions, avoiding the reduction of conductive performance after the addition of polymers. The present invention uses electrochemical grafting and other methods and process parameters to modify the filler, which has the advantages of high efficiency, little damage and little pollution; it better increases the interfacial effect between materials and effectively solves the problem of compatibility between materials. The obtained composite material has excellent electromagnetic shielding performance, ultra-high strength, high corrosion resistance, high conductivity and high thermal stability. When subjected to external stress, it avoids the occurrence of fracture. In addition, even if the composite material obtained by the present invention is corroded by corrosive liquid, it can still have good strength, corrosion resistance, electromagnetic shielding performance, conductivity and thermal stability. Compared with the existing technology, the present invention reduces the raw material production cost, simplifies the process, and breaks the technical bottleneck of the existing technology that will adversely affect the strength, corrosion resistance, conductivity and thermal stability of the material when improving the electromagnetic shielding performance of the material, especially after the material is corroded, it will have an adverse effect on the comprehensive performance of the material. The present invention can achieve the simultaneous improvement of the electromagnetic shielding performance, strength, corrosion resistance, conductivity and thermal stability of the material regardless of before and after corrosion. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a cyclic voltammogram of the carbon nanotube film grafting process in Example 2;

[0016] Figure 2 This is a graph showing the electromagnetic shielding performance of the corrosion-resistant high-strength sandwich structure electromagnetic shielding composite material 6 according to Example 2;

[0017] Figure 3 This is a performance curve diagram of the mechanical properties of the corrosion-resistant high-strength sandwich structure electromagnetic shielding composite material 6 of Example 2. DETAILED DESCRIPTION

[0018] The mechanical property testing instrument used in the present invention is: Japan Shimadzu AG-1KN electronic universal material testing machine. The scanning electron microscope testing instrument is HITACHI-SU8020. The electromagnetic shielding performance testing instrument is the vector network analyzer Agilent PNA-N5244A. The conductivity testing instrument is the four-probe tester Keithley2450. The chemical corrosion resistance test process is as follows: Use a cotton swab to apply the chemical reagent to the middle area of the sample to keep the sample surface wet for at least 1 minute. Then apply it once every 1 hour. After 24 hours, check whether the sample has any adverse phenomena such as damage, cracking, swelling or softening. The chemical reagents are: (1) RP-3 (aviation kerosene); (2) No. 15 hydraulic oil; (3) methyl ethyl ketone; (4) toluene; (5) sodium hydroxide solution; (6) N,N-dimethylformamide.

[0019] Example 1

[0020] (1) Preparation of soluble crystalline polyetheretherketone precursor terminated with phenylacetylene

[0021] 1,1-bis(4-fluorophenyl)-N-phenylformimine (8.85 g), hydroquinone (3.63 g) and anhydrous potassium carbonate (5.4731 g) were added to N-methylpyrrolidone (51 ml) and stirred and mixed. The mixture was reacted at 190° C. for 3 h under a nitrogen atmosphere. 4-Fluoro-4,-(phenylethynyl)benzophenone (4.6 g) was then added at 140° C. and reacted at 155° C. for 5 h. The mixture was then washed with deionized water and ethanol under reflux for 5 times and dried to obtain a soluble crystalline polyetheretherketone precursor terminated with phenylacetylene.

[0022] (2) Preparation of phenylacetylene-grafted graphene films

[0023] At 3°C, 4-fluoro-4,-(phenylethynyl)benzophenone (0.06031 g) and nitrosotetrafluoroborate (0.05475 g) were added to acetonitrile (100 ml), followed by stirring for 15 minutes. Tetrabutyl tetrafluoroborate at a concentration of 0.1 mmol / L was then added and stirred for 15 minutes. A graphene film (0.02 g) was then immersed in the mixed solution and subjected to cyclic voltammetry (CV) for 6 cycles at a rate of 0.01 V / s at a voltage of -0.8 V to 0.8 V. The film was then washed with acetonitrile and water 4 times, respectively, and dried to obtain a phenylacetylene-grafted graphene film.

[0024] (3) Preparation of composite material 1

[0025] The soluble crystalline polyetheretherketone precursor (0.08 g) terminated with phenylacetylene obtained in step (1) is dissolved in N,N-dimethylformamide (10 g) to obtain a polymer solution, and the phenylacetylene-grafted graphene film obtained in step (2) is immersed in the polymer solution and kept at room temperature for 2 hours, and then kept at 50° C. for 8 hours to obtain a composite material 1; the mass ratio of the phenylacetylene-grafted graphene film to the soluble crystalline polyetheretherketone precursor terminated with phenylacetylene is 1:4;

[0026] (4) Preparation of composite material 2

[0027] The composite material 1 obtained in step (3) was placed in hydrochloric acid with a concentration of 6 mol / l, and heated at 120° C. for 10 h to obtain the composite material 2;

[0028] (5) Preparation of corrosion-resistant high-strength sandwich structure electromagnetic shielding composite material 3

[0029] The composite material 2 obtained in step (4) was hot-pressed at 370° C. for 0.5 h to obtain a corrosion-resistant, high-strength sandwich structure electromagnetic shielding composite material 3, which had a conductivity of 256.12 S / cm, an electromagnetic shielding value of 42 dB, and a tensile strength of 148.72 MPa. Composite material 3 was subjected to corrosion resistance tests in N,N-dimethylformamide and a 5 mol / L NaOH solution, respectively. No adverse phenomena such as cracking or softening occurred, and the composite material 3 maintained high electromagnetic shielding performance, strength, corrosion resistance, conductivity, and thermal stability.

[0030] Example 2

[0031] (1) Preparation of soluble crystalline polyetheretherketone precursor terminated with phenylacetylene

[0032] 1,1-bis(4-fluorophenyl)-N-phenylformimine (8.79 g), hydroquinone (3.63 g) and anhydrous potassium carbonate (5.4731 g) were added to sulfolane (51 ml) and stirred and mixed. Toluene (26 ml) was then added and the mixture was reacted at 210° C. for 3 h under a nitrogen atmosphere. 4-fluoro-4,-(phenylethynyl)benzophenone (2.7 g) was then added at 140° C. and the mixture was reacted at 160° C. for 5 h. The mixture was then washed with deionized water and ethanol under reflux for 3 times and dried to obtain a soluble crystalline polyetheretherketone precursor terminated with phenylacetylene.

[0033] (2) Preparation of phenylacetylene-grafted carbon nanotube films

[0034] At 0°C, 4-fluoro-4,-(phenylethynyl)benzophenone (0.1811 g) and nitrosotetrafluoroborate (0.1643 g) were added to acetonitrile (150 ml) to generate a diazonium salt, followed by stirring for 30 min. Tetrabutyl tetrafluoroborate at a concentration of 0.1 mmol / L was then added and stirred for 20 min. A commercial carbon nanotube film (0.04 g) was then immersed in the mixed solution. Cyclic voltammetry was performed at a rate of 0.02 V / s at a voltage of -1 V to -1 V for 5 cycles. The film was then washed with acetonitrile and water three times and then dried to obtain a phenylacetylene-grafted carbon nanotube film. The cyclic voltammetry curve of the phenylacetylene-grafted carbon nanotube film is shown in the attached figure. Figure 1 As shown;

[0035] (3) Preparation of composite material 4

[0036] The soluble crystalline polyetheretherketone precursor (0.06 g) terminated with phenylacetylene obtained in step (1) was dissolved in tetrahydrofuran (6 g) to obtain a polymer solution, and the carbon nanotube film grafted with phenylacetylene obtained in step (2) was immersed in the polymer solution and kept at room temperature for 1 hour, and then kept at 40° C. for 7 hours to obtain composite material 4; the mass ratio of the carbon nanotube film grafted with phenylacetylene to the soluble crystalline polyetheretherketone precursor terminated with phenylacetylene was 1:1.5;

[0037] (4) Preparation of composite material 5

[0038] The composite material 4 obtained in step (3) was placed in hydrochloric acid with a concentration of 6 mol / l, and heated at 120° C. for 10 h to obtain the composite material 5;

[0039] (5) Preparation of corrosion-resistant high-strength sandwich structure electromagnetic shielding composite material 6

[0040] The composite material 5 obtained in step (4) was hot-pressed at 380°C for 0.5h to obtain a corrosion-resistant high-strength sandwich structure electromagnetic shielding composite material 6, whose conductivity was 509.73S / cm. Figure 2Electromagnetic shielding performance curve and attached Figure 3 The mechanical properties curve shows an electromagnetic shielding value of 52dB and a tensile strength of 263.5MPa. Composite material 6 was subjected to corrosion resistance tests in N,N-dimethylformamide and 5mol / l NaOH solution, respectively. No adverse phenomena such as cracking and softening occurred in the corrosion resistance test, and high electromagnetic shielding performance, strength, corrosion resistance, conductivity and thermal stability were maintained. To further verify its corrosion resistance, composite material 6 was immersed in 5mol / l NaOH solution for 15 days and then subjected to electromagnetic shielding and mechanical property tests. Its conductivity was 509.73S / cm, electromagnetic shielding value was 52dB, and tensile strength was 262.44MPa. It can be seen that it can still have high conductivity, electromagnetic shielding and mechanical properties under high concentration corrosive solution and long-term corrosion.

[0041] Example 3

[0042] (1) Preparation of soluble crystalline polyetheretherketone precursor terminated with phenylacetylene

[0043] 1,1-bis(4-fluorophenyl)-N-phenylformimine (7.98 g), hydroquinone (3.63 g) and anhydrous potassium carbonate (5.16 g) were added to N-methylpyrrolidone (48 ml) and stirred and mixed. The mixture was reacted at 180° C. for 4 h under a nitrogen atmosphere. 4-Fluoro-4,-(phenylethynyl)benzophenone (4.3 g) was then added at 140° C. and reacted at 170° C. for 8 h. The mixture was then washed with deionized water and ethanol under reflux for 7 times and dried to obtain a soluble crystalline polyetheretherketone precursor terminated with phenylacetylene.

[0044] (2) Preparation of MXene films grafted with phenylacetylene

[0045] At 0°C, 4-fluoro-4,-(phenylethynyl)benzophenone (0.0965 g) and nitrosotetrafluoroborate (0.0876 g) were added to acetonitrile (100 ml) to generate a diazonium salt, followed by stirring for 10 minutes. Tetrabutyl tetrafluoroborate with a concentration of 0.1 mmol / L was then added and stirred for 10 minutes. The MXene film (0.02 g) was then immersed in the mixed solution. Cyclic voltammetry was performed at a rate of 0.02 V / s at a voltage of -0.8 V to 0.8 V for two cycles. The film was then washed with acetonitrile and water for six times and then dried to obtain a phenylacetylene-grafted MXene film.

[0046] (3) Preparation of composite material 7

[0047] The soluble crystalline polyetheretherketone precursor (0.18 g) terminated with phenylacetylene obtained in step (1) was dissolved in tetrahydrofuran (6 g) to obtain a polymer solution, and the phenylacetylene-grafted MXene film obtained in step (2) was immersed in the polymer solution and kept at room temperature for 0.5 h, and then kept at 40° C. for 4 h to obtain composite material 7; the mass ratio of the phenylacetylene-grafted MXene film to the soluble crystalline polyetheretherketone precursor terminated with phenylacetylene was 1:9;

[0048] (4) Preparation of composite material 8

[0049] The composite material 7 obtained in step (3) was placed in 6 mol / l hydrochloric acid and heated at 120° C. for 12 h to obtain the composite material 8;

[0050] (5) Preparation of corrosion-resistant high-strength sandwich structure electromagnetic shielding composite material 9

[0051] The composite material 8 obtained in step (4) was hot-pressed at 380° C. for 1 hour to obtain a corrosion-resistant, high-strength sandwich-structured electromagnetic shielding composite material 9, which had a conductivity of 300.54 S / cm, an electromagnetic shielding value of 46 dB, and a tensile strength of 120.69 MPa. The composite material 9 was subjected to corrosion resistance tests in N,N-dimethylformamide and a 5 mol / l NaOH solution. No adverse phenomena such as cracking or softening occurred in the corrosion resistance tests, and the composite material maintained high electromagnetic shielding performance, strength, corrosion resistance, conductivity, and thermal stability.

[0052] Table 1 Summary of performance of the embodiments

[0053]

[0054] Comparative Example 1

[0055] In the article Flexible Sandwich-Structured Electromagnetic Interference ShieldingNanocomposite Films with Excellent Thermal Conductivities (Small 2021,17,2101951): Ti3C2T X The Fe3O4 / PVA composite film was prepared by electrospinning and hot pressing to form a Fe3O4 / PVA composite film as the outer layer and Ti3C2T X / PVA as the inner layer to prepare a sandwich structure electromagnetic shielding composite material. XWhen the mass fraction is 40%, the electromagnetic shielding value is 40dB and the tensile strength is 21MPa; when the filler content of the present invention is less than that of the comparative example, it can be seen from Table 1 that the electromagnetic shielding value and tensile strength of the composite material obtained by the present invention are higher than the composite material obtained in comparative example 1. In addition, the present invention also obtains a higher electrical conductivity, thereby simultaneously improving the comprehensive performance of the composite material.

[0056] According to prior art reports, achieving high electromagnetic shielding performance and conductivity in composite materials often reduces material strength and corrosion resistance. This means it's difficult for composite materials to simultaneously improve electromagnetic shielding performance, conductivity, material strength, and corrosion resistance. Compared to the prior art, the composite material obtained by the present invention significantly outperforms the prior art in strength, electromagnetic shielding performance, conductivity, and corrosion resistance. Therefore, compared to the prior art, the present invention achieves simultaneous improvements in electromagnetic shielding performance, conductivity, material strength, and corrosion resistance. Even after corrosion, the composite material of the present invention maintains high electromagnetic shielding performance, conductivity, and strength. Furthermore, while all examples of the present invention utilize different raw materials, formulations, processes, and process parameters, Example 2 achieves the highest tensile strength, electromagnetic shielding, and conductivity. This demonstrates that the optimal performance of the material obtained by the present invention is not determined by a specific raw material, formulation, process, or process parameter, but rather by the synergistic effects of these raw materials, formulations, processes, and process parameters. Furthermore, the optimal performance of the present invention can only be achieved within the scope of the present claims.

Claims

1. A corrosion-resistant, high-strength sandwich structure electromagnetic shielding composite material, characterized in that: Its preparation method comprises the following steps: (1) Preparation of soluble crystalline polyetheretherketone precursor terminated with phenylacetylene 1,1-bis(4-fluorophenyl)-N-phenylformimine, hydroquinone and anhydrous potassium carbonate are added to a solvent and stirred and mixed, and then reacted at 130-210° C. for 3-15 hours under nitrogen protection, and then cooled to 120-140° C., and then 4-fluoro-4,-(phenylethynyl) benzophenone is added, and then heated to 160-200° C. and reacted for 2-10 hours, and then washed, dried and crushed to obtain a soluble crystalline polyetheretherketone precursor terminated with phenylethynyl. The 1,1-bis(4-fluorophenyl)-N The molar ratio of 1,1-bis(4-fluorophenyl)-N-phenylformimine, hydroquinone, anhydrous potassium carbonate and 4-fluoro-4,-(phenylethynyl)benzophenone is 1-1.1:1-1.5:1.3-1.7:0.25-1.5, the solid content of the 1,1-bis(4-fluorophenyl)-N-phenylformimine and hydroquinone in the solvent is 15-25%, and the solvent is one of sulfolane, diphenyl sulfone or N-methylpyrrolidone. The synthesis route of the phenylethynyl-terminated soluble crystalline polyetheretherketone precursor is as follows: (2) Preparation of phenylacetylene grafted films At 0-5° C., 4-fluoro-4,-(phenylethynyl)benzophenone and nitrosotetrafluoroborate are added to 50-150 ml of acetonitrile in a molar ratio of 1:1-2 and stirred for 20-60 minutes. Then, 0.05-0.2 mmol / L of tetrabutyl tetrafluoroborate is added and stirred for another 20-60 minutes to obtain a mixed solution. Then, a thin film material is immersed in the mixed solution. The thin film material is subjected to cyclic voltammetry at a rate of 0.005-0.3 V / s at a voltage of -1.3 V-2 V for 3-20 cycles. The thin film material is then washed with acetonitrile and water for 3-6 times and then dried to obtain a phenylacetylene-grafted thin film. The thin film material is one of a carbon nanotube film, a graphene film, a MXene film, a silver nanowire film, and a carbon fiber film. The mass ratio of the thin film material to acetonitrile is 1:7000-1:4000. (3) the soluble crystalline polyetheretherketone (PEEK) terminated by the phenylacetylene precursor obtained in step (1) is dissolved in a solvent to obtain a polymer solution, and the phenylacetylene grafted film obtained in step (2) is immersed in the polymer solution for 0.5 to 3 hours, and then kept warm at 20 to 60° C. for 6 to 12 hours to obtain a composite material; the mass ratio of the soluble crystalline polyetheretherketone (PEEK) terminated by the phenylacetylene precursor to the solvent is 1:30 to 1000, and the mass ratio of the phenylacetylene grafted film to the soluble crystalline polyetheretherketone (PEEK) terminated by the phenylacetylene precursor is 1:0.1 to 10, and the solvent used is one or any combination of tetrahydrofuran, N-methylpyrrolidone or N,N-dimethylformamide; (4) placing the composite material obtained in step (3) in hydrochloric acid having a concentration of 3 to 20 mol / l, heating to 110 to 150° C., and placing for 5 to 15 hours to obtain composite material 1; (5) The composite material 1 obtained in step (4) is hot-pressed at 360-420° C. for 0.5-3 h to obtain a corrosion-resistant high-strength sandwich structure electromagnetic shielding composite material, wherein the corrosion-resistant high-strength sandwich structure electromagnetic shielding composite material is a grafted structure; the corrosion-resistant high-strength sandwich structure electromagnetic shielding composite material has excellent electromagnetic shielding performance, ultra-high strength, corrosion resistance, conductivity and thermal stability, and its conductivity is 150-2000 S / cm, the electromagnetic shielding value is between 42-100 dB, and the tensile strength is 115-350 MPa. After corrosion treatment, it still has excellent strength, corrosion resistance, electromagnetic shielding performance, conductivity and thermal stability.

2. The corrosion-resistant high-strength sandwich structure electromagnetic shielding composite material according to claim 1, characterized in that: The corrosion-resistant high-strength sandwich structure electromagnetic shielding composite material has a conductivity of 250 to 1500 S / cm, an electromagnetic shielding value of 46 to 90 dB, and a tensile strength of 120 to 280 MPa.

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