High-entropy nano-alloy fiber wave-absorbing material, preparation method thereof and wave-absorbing non-woven cloth
Through the electrospinning and high-temperature calcining preparation method of high entropy nano alloy fibers, the problem of the performance of absorbent materials being affected by environmental factors is solved, and a combination of high stability and excellent microwave absorption performance is achieved.
Patent Information
- Application Number
- CN202510368263.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-26
- Publication Date
- 2025-06-20
AI Technical Summary
The microwave absorption performance of existing absorbent materials is greatly affected by environmental factors such as temperature and humidity, resulting in unstable performance.
High-entropy nanoalloy fibers are used as wave absorbing material and prepared by combining electrospinning and high-temperature calcination to form high-entropy nanoalloy fibers with uniform morphology and uniform distribution of polymetallic nanoparticles.
While ensuring excellent microwave absorption performance, the performance stability of the material is improved, so that the microwave absorption performance of the absorbing material is less affected by environmental factors such as temperature and humidity.
Smart Images
Figure CN120174512A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of microwave absorbing materials, and particularly to a high-entropy nanoalloy fiber microwave absorbing material, a preparation method thereof, and a microwave absorbing non-woven fabric. Background Art
[0002] A microwave absorbing material is a special functional material that can convert the energy of incident electromagnetic waves into heat energy or other forms of energy, thereby reducing the reflection of electromagnetic waves. Its core principle is to achieve the loss and attenuation of electromagnetic waves through the conductivity, magnetic permeability, dielectric constant and other characteristics of the material itself. At present, microwave absorbing materials are widely used in military, civilian, aerospace, communication and other fields.
[0003] Existing microwave absorbing materials, such as ferrites, metal powders, graphite, carbon nanotubes and conductive polymers, although having excellent microwave absorption performance, are greatly affected by environmental factors such as temperature and humidity, which limits their applications. Summary of the Invention
[0004] In order to solve the problem that the microwave absorption performance of microwave absorbing materials in the prior art is greatly affected by environmental factors such as temperature and humidity, the present invention provides a preparation method of a high-entropy nanoalloy fiber microwave absorbing material. The prepared high-entropy nanoalloy fiber microwave absorbing material enhances the performance through the synergy between elements, while ensuring excellent microwave absorption performance, endowing the material with excellent performance stability, and solving the problem that the microwave absorption performance of microwave absorbing materials in the prior art is greatly affected by environmental factors such as temperature and humidity.
[0005] The technical solution adopted by the present invention to solve its technical problems is as follows: A preparation method of a high-entropy nanoalloy fiber microwave absorbing material, comprising the following steps: S1: Dissolve a polymer in a mixed solvent of DMF and acetone to form a solution, and then add five or more metal salts, and stir at 60-80 °C to obtain a spinning solution; S2: Electrospinning the spinning solution to obtain a high-entropy alloy nanofiber precursor; S3: Pre-oxidize the high-entropy alloy nanofiber precursor in air at 220-240 °C, and then calcine it at 800-900 °C to obtain a high-entropy nanoalloy fiber microwave absorbing material.
[0006] Optionally, the polymer in step S1 is selected from at least one of polyacrylonitrile, polyvinylidene fluoride, polyimide, polymethyl methacrylate, and polystyrene.
[0007] Optionally, the metal salt is selected from at least one of nitrates, acetates, chlorides or sulfates of Au, Ag, Pt, Pd, Co, Mg, Ni, Cu, Zn, Mn, Sn, Mo, Ce or Fe.
[0008] Another object of the present invention is to provide a high-entropy nanoalloy fiber absorbing material, which is prepared by the preparation method of the high-entropy nanoalloy fiber absorbing material as described above.
[0009] Another object of the present invention is to provide a non-woven absorbing fabric, which includes two non-woven fabric layers and an absorbing layer disposed between the two non-woven fabric layers; the absorbing layer includes the high-entropy nanoalloy fiber absorbing material as described above.
[0010] Optionally, by weight, the raw materials of the absorbing layer include the following components: High-entropy nanoalloy fiber absorbing material 0.1 - 0.5 parts; Organic solvent 10 - 20 parts; Modified flow agent 1 - 5 parts; Phenolic resin 10 - 20 parts; Amino resin 10 - 20 parts.
[0011] Optionally, the high-entropy nanoalloy fiber absorbing material is a surface-modified high-entropy nanoalloy fiber; the surface-modified high-entropy nanoalloy fiber is prepared by the following method: dispersing the high-entropy nanoalloy fiber absorbing material in ethanol, adding a low-molecular-weight organic polymer, stirring and reacting, and then drying to obtain the surface-modified high-entropy nanoalloy fiber.
[0012] Optionally, the organic polymer is selected from at least one of polyether polyol, polyester polyol, alcoholysis nylon, polyester-modified acrylic resin, polyvinyl butyral, and butyral ethylene glycol.
[0013] Optionally, the organic solvent is selected from at least one of absolute ethanol, toluene, benzene, acetone, and acrylic acid.
[0014] Optionally, the modified flow agent is selected from at least one of hydroxyl-terminated hyperbranched polyester, carboxyl-terminated hyperbranched polyester, hyperbranched unsaturated resin, aqueous chlorinated polypropylene emulsion, water-soluble epoxy resin emulsion, hyperbranched polyamide resin, and amino-terminated hyperbranched polyamide.
[0015] The beneficial effects of the present invention are: The preparation method of the high-entropy nanoalloy fiber absorbing material provided by the present invention combines electrospinning and high-temperature calcination to prepare high-entropy nanoalloy fibers with uniform morphology and uniform distribution of multi-metal nanoparticles. Through the synergistic enhancement of performance among various elements, the high-entropy nanoalloy fibers endow the material with excellent performance stability while ensuring excellent microwave absorption performance, so that the microwave absorption performance of the absorbing material is less affected by environmental factors such as temperature and humidity. Brief Description of the Drawings
[0016] The present invention will be further described below with reference to the drawings and embodiments.
[0017] Figure 1 is a schematic structural diagram of the absorbing non-woven fabric in the present invention; Figure 2 is a TEM image of the high-entropy nanoalloy fibers prepared in Example 1 of the present invention; Figure 3 is a TEM image of the high-entropy nanoalloy fibers prepared in Example 2 of the present invention. Detailed Description of the Embodiments
[0018] The present invention will now be described in further detail. The following described embodiments are exemplary and are intended to explain the present invention and should not be construed as limiting the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts fall within the scope of protection of the present invention.
[0019] To solve the problem that the microwave absorption performance of the absorbing material in the prior art is greatly affected by environmental factors such as temperature and humidity, the present invention provides a preparation method of a high-entropy nanoalloy fiber absorbing material, and the preparation method includes the following steps: S1: Dissolve the polymer in a mixed solvent of DMF and acetone to form a solution, and then add five or more metal salts, and stir at 60-80 °C to obtain a spinning solution; Preferably, the mass fraction of the polymer in the solution of this step is 8 wt%-12 wt%; the mass ratio of DMF to acetone in the mixed solvent is (1-2):1; preferably, the mass ratio of the metal salt to the solution is (1~5):100; S2: Electrospin the spinning solution to obtain a high-entropy alloy nanofiber precursor; Preferably, in this step, the above spinning solution is electrospun at a voltage of 15.0-20.0 kV to obtain a high-entropy alloy nanofiber precursor; the process parameters of electrospinning are: the flow rate of the spinning solution is 0.06-0.1 mL / min, the applied voltage is 15.0-20.0 kV, and the distance between the roller and the needle tip is 15-17 cm; S3: Pre-oxidize the high-entropy alloy nanofiber precursor in air at 220 - 240 °C, and then calcine it at 800 - 900 °C to obtain the high-entropy nano-alloy fiber microwave absorption material; Preferably, step S3 is specifically carried out according to the following method: Place the high-entropy alloy nanofiber precursor in a tube furnace. First, under air conditions, heat it at a rate of 2 - 5 °C / min to the target temperature at 220 - 240 °C (preferably 240 °C); further, maintain it at the target temperature for 3 - 4 h for pre-oxidation; then heat the pre-oxidized fiber at a rate of 2 - 5 °C / min to the target temperature of 800 - 900 °C, and maintain it at the target temperature for 3 - 4 h to obtain the high-entropy nano-alloy fiber microwave absorption material.
[0020] High-entropy nano-alloy is a multi-metal nano-alloy. The composition of high-entropy nanoparticles is relatively flexible, and high-entropy nano-alloys can significantly improve the structural stability of materials. Compared with single-metal materials, high-entropy nano-alloys have two typical characteristics: (1) Multiple elements can endow the material with a broad composition space, providing many composition choices for the design and development of nano-alloys; (2) The complex atomic configuration generated by the random mixing of multiple elements; Due to its unique multi-ion effect, high-entropy nano-alloys achieve local charge accumulation and strain regulation, can cause nodal relaxation performance, and effectively attenuate the energy of electromagnetic waves.
[0021] The preparation method of the high-entropy nano-alloy fiber microwave absorption material provided by the present invention combines electrospinning and high-temperature calcination to prepare high-entropy nano-alloy fibers with uniform morphology and uniform distribution of multi-metal nanoparticles; through the synergistic enhancement of performance among various elements, the high-entropy nano-alloy fibers endow the material with excellent corrosion resistance while ensuring excellent microwave absorption performance, and the preparation cost is relatively low.
[0022] Preferably, the polymer in step S1 of the present invention is selected from at least one of polyacrylonitrile (PAN), polyvinylidene fluoride (PVDF), polyimide (PEI), polymethyl methacrylate (PMMA), and polystyrene (PS).
[0023] To ensure the microwave absorption performance of the material, preferably, the metal salt of the present invention is selected from at least one of nitrates, acetates, chlorides, or sulfates of Au, Ag, Pt, Pd, Co, Mg, Ni, Cu, Zn, Mn, Sn, Mo, Ce, or Fe; specifically, preferably, the metal salt of the present invention is selected from at least five of magnesium nitrate, cobalt nitrate, nickel nitrate, copper acetate, zinc acetate, iron chloride, cobalt chloride, and magnesium chloride, and the molar ratio of the above metals is in any proportion.
[0024] Another object of the present invention is to provide a high-entropy nanoalloy fiber absorbing material, which is prepared by the preparation method of the high-entropy nanoalloy fiber absorbing material as described above.
[0025] In the preparation process of the high-entropy nanoalloy fiber absorbing material provided by the present invention, electrospinning and high-temperature calcination are combined to prepare high-entropy nanoalloy fibers with uniform morphology and uniform distribution of multi-metal nanoparticles; through the synergistic enhancement of performance between elements, the high-entropy nanoalloy fibers ensure excellent microwave absorption performance while endowing the material with excellent performance stability, making the microwave absorption performance of the absorbing material less affected by environmental factors such as temperature and humidity.
[0026] Another object of the present invention is to provide a non-woven absorbing fabric. Referring to Figure 1 As shown, the non-woven absorbing fabric includes two non-woven fabric layers and an absorbing layer disposed between the two non-woven fabric layers; the absorbing layer includes the high-entropy nanoalloy fiber absorbing material as described above.
[0027] The non-woven fabric is a fabric made of ultra-high molecular weight polyethylene fibers, carbon fibers or aramid as the base material, uniformly laid with filaments by an automated device, and compounded with elastic polyurethane, rubber-based resin or polyolefin film to form a unidirectional UD layer. After being orthogonally arranged at 0° / 90° or multi-layer orthogonally arranged at 0° / 90°, it is compounded under a certain pressure.
[0028] The non-woven absorbing fabric provided by the present invention, by adopting a composite sandwich structure, bonding the high-entropy nanoalloy fiber absorbing material as the absorbing layer with the non-woven fabric, can effectively reduce the overall density of the composite non-woven fabric, and the high-entropy nanoalloy fiber absorbing material in the middle can effectively promote electron transfer and effectively improve the absorbing performance of the composite sandwich structure.
[0029] The non-woven fabric in the present invention is a fabric woven from ultra-high molecular weight polyethylene, polypropylene, polyamide, carbon fiber or aramid fiber; preferably, the non-woven fabric is selected from at least one of HT / UD001, SWT-001, DY-8UD, FL20211124-UD003, TWL-FLYYS320.
[0030] Specifically, preferably by weight, the raw materials of the absorbing layer include the following components: High-entropy nanoalloy fiber absorbing material 0.1 - 0.5 parts; Organic solvent 10 - 20 parts; Modified flow agent 1 - 5 parts; Phenolic resin 10 - 20 parts; Amino resin 10 - 20 parts.
[0031] By dispersing the high-entropy nano-alloy fiber absorbing material in thermoplastic phenolic resin and amino resin, the high-entropy nano-alloy fiber absorbing material can be bonded as an absorbing layer between two layers of non-woven fabrics.
[0032] To improve the dispersibility and bonding performance of the high-entropy nano-alloy fiber absorbing material in the matrix resin, the present invention preferably uses the high-entropy nano-alloy fiber absorbing material as the surface-modified high-entropy nano-alloy fiber; the surface-modified high-entropy nano-alloy fiber is prepared by the following method: dispersing the high-entropy nano-alloy fiber absorbing material in ethanol, adding a low-molecular-weight organic polymer, stirring and reacting at 50-60 °C for 5-6 h, and then drying at 60-80 °C for 4-6 h to obtain the surface-modified high-entropy nano-alloy fiber.
[0033] Preferably, the mass ratio of the high-entropy nano-alloy fiber absorbing material, ethanol, and the low-molecular-weight organic polymer is (0.5-1):(50-70):(1-5).
[0034] The surface-modified high-entropy nano-alloy fiber provided by the present invention can form an internal cross-linked network structure with the phenolic resin and amino resin of the matrix, further improving the dispersibility and bonding performance of the high-entropy nano-alloy in the matrix resin.
[0035] The present invention preferably selects the low-molecular-weight organic polymer from at least one of polyether polyol, polyester polyol, alcoholysis nylon, polyester-modified acrylic resin, polyvinyl butyral, and butyral ethylene glycol.
[0036] Furthermore, in the raw materials of the absorbing layer of the present invention, the organic solvent is preferably selected from at least one of anhydrous ethanol, toluene, benzene, acetone, and acrylic acid, and is preferably anhydrous ethanol.
[0037] Preferably, the modified flow agent is a low-molecular-weight polymer. Specifically, the modified flow agent is preferably selected from at least one of hydroxyl-terminated hyperbranched polyester, carboxyl-terminated hyperbranched polyester, hyperbranched unsaturated resin, aqueous chlorinated polypropylene emulsion, water-soluble epoxy resin emulsion, hyperbranched polyamide resin, and amino-terminated hyperbranched polyamide; furthermore, the modified flow agent is preferably selected from at least one of HyPer H10, HyPer H20, HyPer H30, HyPer H40, HyPer C10, HyPer C20, HyPer C30, HyPerC40, HyPer U102, HyPer E102, HyPer CPP25, HyPer WE1051A, HyPer HPN202, and HyPer N10.
[0038] The phenolic resin preferably used in the present invention is a thermoplastic phenolic resin. Specifically, the preferred phenolic resin is selected from at least one of 2123, 2402, 2124, 2140, 2123F, and JM-939.
[0039] The amino resin preferably used in the present invention is a resin with amino functional groups, having excellent heat resistance and chemical corrosion resistance. Specifically, the preferred amino resin is selected from at least one of CYMEL 303LF, CYMEL 325, A-33, Haminol 325W, RESIMENE 747, and ETERMINO 9218-75.
[0040] The preparation of the wave-absorbing non-woven fabric in the present invention mainly includes two processes: First, prepare the glue of the high-entropy nanoalloy fiber wave-absorbing material, and then evenly apply the prepared glue of the nanoalloy fiber wave-absorbing material on the non-woven fabric with a certain thickness for heat treatment. After heat treatment, a wave-absorbing non-woven fabric with a sandwich structure is obtained. The preparation process of the above wave-absorbing non-woven fabric is as follows: (1) According to the formulation amount, disperse the surface-modified high-entropy nanoalloy fibers prepared in an organic solution to form a homogeneous solution A; (2) Add a modified fluidizing agent to the homogeneous solution A prepared in step (1) to improve the viscosity of the system, and disperse it evenly by magnetic stirring to form solution B; (3) Add phenolic resin and amino resin to the above solution B and stir evenly to form a homogeneous solution C; (4) Evenly apply the homogeneous solution C prepared in the above steps on the non-woven fabric, where the gap of the scraper is adjusted to 100-150 um for gluing. After gluing, cover another non-woven fabric above the glue to form a sandwich structure; place the above sandwich-structured composite material in a vacuum oven for treatment, where the treatment temperature is 80-90 °C and the treatment time is 30-50 min to obtain a wave-absorbing non-woven fabric with a sandwich structure.
[0041] The wave-absorbing non-woven fabric provided by the present invention designs a composite sandwich structure, disperses high-entropy nanoalloy fibers in thermoplastic phenolic resin and amino resin, and uses it as the core layer to bond the non-woven fabric, which can effectively reduce the overall density of the composite non-woven fabric. The high-entropy nanoalloy fibers in the middle can effectively promote electron transfer and effectively improve the wave-absorbing performance of the composite sandwich structure.
[0042] To make the above objects, features, and advantages of the present invention more obvious and understandable, the following will describe the specific embodiments of the present invention in detail with reference to the accompanying drawings.
[0043] Example 1 This embodiment provides a wave-absorbing non-woven fabric, which is prepared according to the following method: (1) By weight, 0.1 part by weight of surface-modified NiCoFeCuMo alloy fibers are dispersed in 15 parts by weight of ethanol to form a homogeneous solution A; (2) 1 part by weight of HyPer H10 is added to the homogeneous solution A prepared in step (1), and dispersed evenly by magnetic stirring to form a solution B; (3) 10 parts of 2123 and 20 parts of CYMEL 303LF are added to the above solution B, and stirred evenly to form a homogeneous solution C; (4) The homogeneous solution C prepared in the above steps is evenly coated on a non-woven fabric (the material is HT / UD0001), wherein the gap of the scraper is adjusted to 100 μm for gluing; after gluing, a layer of non-woven fabric is covered above the glue to form a sandwich structure. The above sandwich structure composite material is placed in a vacuum oven for treatment, wherein the treatment temperature is 80 °C and the treatment time is 30 min; a wave-absorbing non-woven fabric with a NiCoFeCuMo alloy fiber sandwich structure is obtained; The preparation process of the NiCoFeCuMo alloy fibers is as follows: (1) Preparation of the precursor solution: First, PAN is completely dissolved in a mixed solvent of DMF and acetone to form an 8 wt% solution, and then nitrates of five metals, Ni, Co, Fe, Cu, and Mo, are added. The molar ratio of the five metal nitrates is 1:1:1:1:0.5; the mass ratio of DMF to acetone in the mixed solvent is 1:1; the mass ratio of the five metal nitrates to the solution is 1:100; the mixture is stirred at 60 °C to obtain a homogeneous spinning solution; the above homogeneous solution is electrospun at a voltage of 15.0 kV to obtain precursor NiCoFeCuMo high-entropy alloy nanofibers; the process parameters of electrospinning are: the flow rate of the precursor solution is 0.06 mL / min, the applied voltage is 15.0 kV, and the distance between the roller and the needle tip is 15 cm; (2) Preparation of NiCoFeCuMo alloy fibers: The NiCoFeCuMo fibers prepared in step (1) are dried and placed in a tubular furnace; first, under air conditions, the temperature is raised to the target temperature at a rate of 2 °C / min at 240 °C, and further maintained at the target temperature for 3 h for pre-oxidation; the pre-oxidized fibers are further heated to the target temperature of 850 °C at a rate of 2 °C / min and maintained for 3.5 h to obtain NiCoFeCuMo alloy fibers, and the TEM image is shown in Figure 2 as shown.
[0044] The surface modification treatment of NiCoFeCuMo alloy fibers is carried out according to the following method: First, the NiCoFeCuMo alloy fibers are ultrasonically dispersed in ethanol with a mass fraction of 8 wt%. Low molecular weight polyether polyol is added, and after stirring and reacting at 50 °C for 5 h, it is dried at 60 °C for 6 h to obtain the surface-modified NiCoFeCuMo alloy fibers. The mass ratio of NiCoFeCuMo alloy fibers, ethanol, and polyether polyol is 0.5:50:1.
[0045] Example 2 This example provides a wave-absorbing non-woven fabric, which is prepared according to the following method: (1) By weight, 0.2 parts by weight of the surface-modified NiCoFeAuMo alloy fibers are dispersed in 15 parts by weight of ethanol to form a homogeneous solution A; (2) 2 parts by weight of HyPer H40 are added to the homogeneous solution A prepared in step (1), and after being uniformly dispersed by magnetic stirring, a solution B is formed; (3) 15 parts of 2402 and 15 parts of CYMEL 303LF are added to the above solution B and stirred evenly to form a homogeneous solution C; (4) The homogeneous solution C prepared in the above steps is evenly coated on the non-woven fabric (material: SWT-001), where the gap of the scraper is adjusted to 100 μm for gluing; after gluing, a layer of non-woven fabric is covered above the glue to form a sandwich structure. The above sandwich structure composite material is placed in a vacuum oven for treatment, where the treatment temperature is 80 °C and the treatment time is 30 min; a NiCoFeCuMo alloy fiber sandwich structure wave-absorbing non-woven fabric is obtained; The preparation process of the NiCoFeCuMo alloy fibers is as follows: (1) Preparation of the precursor solution: First, PAN is completely dissolved in a mixed solvent of DMF and acetone to form an 8 wt% solution, and then nitrates of five metals, Ni, Co, Fe, Au, and Mo, are added. The molar ratio of the five metal nitrates is 1:1:1:1:1; the mass ratio of DMF to acetone in the mixed solvent is 2:1; the mass ratio of the five metal nitrates to the solution is 1.5:100; the solution is stirred at 60 °C to obtain a uniform spinning solution; the above uniformly mixed solution is electrospun at a voltage of 15.0 kV to obtain precursor NiCoFeAuMo high-entropy alloy nanofibers; the process parameters of electrospinning are: the flow rate of the precursor solution is 0.06 mL / min, the applied voltage is 15.0 kV, and the distance between the roller and the needle tip is 15 cm; (2)Preparation of NiCoFeAuMo alloy fibers: The NiCoFeAuMo fibers prepared in step (1) were dried and placed in a tubular furnace. First, under air conditions, the temperature was raised to the target temperature at a rate of 2 °C / min at 240 °C, and further maintained at the target temperature for 3 h for pre-oxidation. The pre-oxidized fibers were further heated to the target temperature of 850 °C at a rate of 2 °C / min and maintained for 3.5 h to obtain NiCoFeAuMo alloy fibers. The TEM image is shown in Figure 3 as follows.
[0046] The NiCoFeAuMo alloy fibers were surface-modified as follows: First, the NiCoFeAuMo alloy fibers were ultrasonically dispersed in ethanol at a mass fraction of 8 wt%, and low-molecular-weight polyether polyol was added. After stirring and reacting at 55 °C for 6 h, it was dried at 80 °C for 6 h to obtain surface-modified NiCoFeAuMo alloy fibers. The mass ratio of NiCoFeAuMo alloy fibers, ethanol, and polyether polyol is 1:60:5.
[0047] Example 3 This example provides a wave-absorbing non-woven fabric, which is prepared as follows: (1)By weight, 0.2 parts by weight of surface-modified AgNiCoFeAuMo alloy fibers were dispersed in 15 parts by weight of ethanol to form a homogeneous solution A; (2)5 parts by weight of HyPer WE1051A was added to the homogeneous solution A prepared in step (1) and dispersed evenly by magnetic stirring to form solution B; (3)20 parts of 2140 and 10 parts of CYMEL 303LF were added to the above solution B and stirred evenly to form a homogeneous solution C; (4)The homogeneous solution C prepared in the above steps was evenly coated on a non-woven fabric (made of DY-8UD), with the gap of the doctor blade adjusted to 100 μm for gluing. After gluing, another non-woven fabric was covered above the glue to form a sandwich structure. The above sandwich-structured composite material was placed in a vacuum oven for treatment, with the treatment temperature of 80 °C and the treatment time of 30 min to obtain a wave-absorbing non-woven fabric with a sandwich structure of AgNiCoFeAuMo alloy fibers; The preparation process of the AgNiCoFeAuMo alloy fibers is as follows: (1)Preparation of precursor solution: First, PAN was completely dissolved in a mixed solvent of DMF and acetone to form an 8 wt% solution. Then, nitrates of six metals, namely Ag, Ni, Co, Fe, Au, and Mo, were added. The molar ratio of the six metal nitrates was 2:1:1:0.5:1:0.5; the mass ratio of DMF to acetone in the mixed solvent was 2:1; the mass ratio of the six metal nitrates to the solution was 1:100; the mixture was stirred at 60 °C to obtain a homogeneous spinning solution; the above-mentioned well-mixed solution was electrospun at a voltage of 15.0 kV to obtain precursor NiCoFeAuMo high-entropy alloy nanofibers; the process parameters of electrospinning were: the flow rate of the precursor solution was 0.06 mL / min, the applied voltage was 15.0 kV, and the distance between the roller and the needle tip was 15 cm; (2)Preparation of AgNiCoFeAuMo alloy fibers: The AgNiCoFeAuMo fibers prepared in step (1) were dried and placed in a tube furnace; first, under air conditions, the temperature was raised to the target temperature at a rate of 2 °C / min at 240 °C, and further maintained at the target temperature for 3 h for pre-oxidation; the pre-oxidized fibers were further heated to the target temperature of 850 °C at a rate of 2 °C / min and maintained for 3.5 h to obtain AgNiCoFeAuMo alloy fibers.
[0048] The AgNiCoFeAuMo alloy fibers were surface-modified as follows: First, the AgNiCoFeAuMo alloy fibers were ultrasonically dispersed in ethanol with a mass fraction of 8 wt%, and low molecular weight polyether polyol was added. After stirring and reacting at 60 °C for 6 h, the mixture was dried at 80 °C for 6 h to obtain surface-modified AgNiCoFeAuMo alloy fibers. The mass ratio of AgNiCoFeAuMo alloy fibers to polyether polyol was 0.5:70:2.
[0049] In this invention, each comparative example was compared with Example 1.
[0050] Comparative Example 1 This comparative example provides a non-woven fabric, which was prepared as follows: (1)By weight, 1 part of HyPer H10 was added to 15 parts of ethanol and dispersed evenly by magnetic stirring to form solution A; (2)10 parts of 2123 and 20 parts of CYMEL 303LF were added to the above solution A and stirred evenly to form a homogeneous solution B; (4) Uniformly apply the homogeneous solution B prepared in the above steps on the non-woven fabric (made of HT / UD0001), where the gap of the doctor blade is adjusted to 100 μm for gluing; after gluing, cover another layer of non-woven fabric above the glue to form a sandwich structure. Place the above sandwich-structured composite material in a vacuum oven for treatment, where the treatment temperature is 80 °C and the treatment time is 30 min; obtain the non-woven fabric with a sandwich structure.
[0051] Comparative Example 2 This comparative example provides a wave-absorbing non-woven fabric, which is prepared according to the following method: (1) By weight, disperse 0.1 part by weight of NiCoFeCuMo alloy fibers in 15 parts by weight of ethanol to form a homogeneous solution A; (2) Add 1 part by weight of HyPer H10 to the homogeneous solution A prepared in step (1), and disperse it evenly by magnetic stirring to form solution B; (3) Add 10 parts of 2123 and 20 parts of CYMEL 303LF to the above solution B, and stir evenly to form a homogeneous solution C; (4) Uniformly apply the homogeneous solution C prepared in the above steps on the non-woven fabric (made of HT / UD0001), where the gap of the doctor blade is adjusted to 100 μm for gluing; after gluing, cover another layer of non-woven fabric above the glue to form a sandwich structure. Place the above sandwich-structured composite material in a vacuum oven for treatment, where the treatment temperature is 80 °C and the treatment time is 30 min; obtain the wave-absorbing non-woven fabric with a NiCoFeCuMo alloy fiber sandwich structure; The preparation process of the NiCoFeCuMo alloy fibers is as follows: (1) Preparation of the precursor solution: First, completely dissolve PAN in a mixed solvent of DMF and acetone to form an 8 wt% solution, then add nitrates of five metals, Ni, Co, Fe, Cu, and Mo. The molar ratio of the five metal nitrates is 1:1:1:1:0.5; the mass ratio of DMF to acetone in the mixed solvent is 1:1; the mass ratio of the five metal nitrates to the solution is 1:100; stir at 60 °C to obtain a uniform spinning solution; electrospin the above uniformly mixed solution at a voltage of 15.0 kV to obtain precursor NiCoFeCuMo high-entropy alloy nanofibers; the process parameters of electrospinning are: the flow rate of the precursor solution is 0.06 mL / min, the applied voltage is 15.0 kV, and the distance between the roller and the needle tip is 15 cm; (2)Preparation of NiCoFeCuMo alloy fibers: The NiCoFeCuMo fibers prepared in step (1) were dried and placed in a tube furnace. First, under air conditions, the temperature was raised to the target temperature at a rate of 2 °C / min at 240 °C, and further maintained at the target temperature for 3 h for pre-oxidation. The pre-oxidized fibers were further heated to the target temperature of 850 °C at a rate of 2 °C / min and maintained for 3.5 h to obtain NiCoFeCuMo alloy fibers.
[0052] Comparative Example 3 This comparative example provides a wave-absorbing non-woven fabric, which is prepared according to the following method: (1)By weight, 0.1 part by weight of surface-modified NiCoFeCuMo alloy fibers was dispersed in 15 parts by weight of ethanol to form a homogeneous solution A; (2)1 part by weight of HyPer H10 was added to the homogeneous solution A prepared in step (1), and dispersed evenly by magnetic stirring to form solution B; (3)30 parts of 2123 was added to the above solution B and stirred evenly to form a homogeneous solution C; (4)The homogeneous solution C prepared in the above steps was evenly coated on a non-woven fabric (material: HT / UD0001), where the gap of the scraper was adjusted to 100 μm for gluing; after gluing, a layer of non-woven fabric was covered above the glue to form a sandwich structure. The above sandwich-structured composite material was placed in a vacuum oven for treatment, where the treatment temperature was 80 °C and the treatment time was 30 min; a wave-absorbing non-woven fabric with a NiCoFeCuMo alloy fiber sandwich structure was obtained; The preparation process of the NiCoFeCuMo alloy fibers is as follows: (1)Preparation of the precursor solution: First, PAN was completely dissolved in a mixed solvent of DMF and acetone to form an 8 wt% solution, and then nitrates of five metals, Ni, Co, Fe, Cu, and Mo, were added. The molar ratio of the five metal nitrates was 1:1:1:1:0.5; the mass ratio of DMF to acetone in the mixed solvent was 1:1; the mass ratio of the five metal nitrates to the solution was 1:100; the solution was stirred at 60 °C to obtain a homogeneous spinning solution; the above homogeneous solution was electrospun at a voltage of 15.0 kV to obtain precursor NiCoFeCuMo high-entropy alloy nanofibers; the process parameters of electrospinning were: the flow rate of the precursor solution was 0.06 mL / min, the applied voltage was 15.0 kV, and the distance between the roller and the needle tip was 15 cm; (2)Preparation of NiCoFeCuMo alloy fibers: The NiCoFeCuMo fibers prepared in step (1) were dried and placed in a tubular furnace. First, under air conditions, the temperature was raised to the target temperature at a rate of 2 °C / min at 240 °C, and further maintained at the target temperature for 3 h for pre-oxidation. The pre-oxidized fibers were further heated to the target temperature of 850 °C at a rate of 2 °C / min and maintained for 3.5 h to obtain NiCoFeCuMo alloy fibers.
[0053] The surface modification treatment of NiCoFeCuMo alloy fibers was carried out according to the following method: First, the NiCoFeCuMo alloy fibers were ultrasonically dispersed in ethanol with a mass fraction of 8 wt%, and low molecular weight polyether polyol was added. After stirring and reacting at 50 °C for 5 h, it was dried at 60 °C for 6 h to obtain the surface-modified NiCoFeCuMo alloy fibers. The mass ratio of NiCoFeCuMo alloy fibers, ethanol, and polyether polyol was 0.5:50:1.
[0054] Comparative Example 4: This comparative example provides a wave-absorbing non-woven fabric, which was prepared according to the following method: (1)By weight, 0.1 part by weight of surface-modified carbon nanotubes was dispersed in 15 parts by weight of ethanol to form a homogeneous solution A; (2)1 part by weight of HyPer H10 was added to the homogeneous solution A prepared in step (1) and dispersed evenly by magnetic stirring to form solution B; (3)10 parts of 2123 and 20 parts of CYMEL 303LF were added to the above solution B and stirred evenly to form a homogeneous solution C; (4)The homogeneous solution C prepared in the above steps was evenly coated on a non-woven fabric (made of HT / UD0001), with the gap of the doctor blade adjusted to 100 μm for gluing. After gluing, a layer of non-woven fabric was covered above the glue to form a sandwich structure. The above sandwich-structured composite material was placed in a vacuum oven for treatment, with the treatment temperature of 80 °C and the treatment time of 30 min; a carbon nanotube sandwich-structured wave-absorbing non-woven fabric was obtained; The modification process of the carbon nanotubes is as follows: First, the carbon nanotubes were ultrasonically dispersed in ethanol with a mass fraction of 8 wt%, and low molecular weight polyether polyol was added. After stirring and reacting at 50 °C for 5 h, it was dried at 60 °C for 6 h to obtain the surface-modified carbon nanotubes. The mass ratio of carbon nanotubes, ethanol, and polyether polyol was 0.5:50:1.
[0055] The performance of the non-woven fabrics prepared in the above examples and comparative examples was characterized as follows: Peel strength: The samples were tested using a universal testing machine in accordance with the standard of GB / T 2790-1995; Flexural strength: The samples were tested using a universal testing machine in accordance with the standard of GB / T 9431-2008; Wave absorption performance: The electromagnetic parameters of the samples in the frequency range of 2-18 GHz were tested using a vector network analyzer.
[0056] Wet heat aging treatment: The wave-absorbing non-woven fabrics prepared in Examples 1-3 and Comparative Examples 1-4 were immersed in a beaker of deionized water, and the beaker was placed in a water bath at 70 °C for heat preservation. After 25 days of continuous wet heat aging, the bending test was carried out.
[0057] The characterization results are shown in Table 1: Table 1 Peeling strength / N·mm Flexural strength / Mpa Reflection loss / dB Flexural strength (after damp heat aging treatment) / Mpa Example 1 12.30 34.56 65.62 33.28 Example 2 12.45 35.78 64.98 35.55 Example 3 13.26 36.01 65.12 35.98 Comparative example 1 10.56 25.15 25.11 25.01 Comparative example 2 11.26 26.11 41.23 26.09 Comparative example 3 9.56 31.24 45.26 18.24 Comparative example 4 10.23 33.23 41.23 25.12 It can be seen from the above table that the wave-absorbing non-woven fabrics prepared in the examples of the present invention all have excellent mechanical properties and wave absorption performance.
[0058] The difference between Comparative Example 1 and Example 1 is that the high-entropy nanoalloy fiber was not introduced, and the difference in the reflection loss value of the prepared non-woven fabric was increased. The wave absorption performance of the non-woven fabric with the introduction of high-entropy nanoalloy fiber is more excellent; at the same time, compared with Example 1, the peel strength and flexural strength have a significant decrease in performance.
[0059] The difference between Comparative Example 2 and Example 1 is that the introduced high-entropy nanoalloy fiber was not surface-modified, and the difference in the values of the peel strength and flexural strength of the prepared non-woven fabric was increased. This may be due to the poor distribution of the unmodified high-entropy nanoalloy fiber in the matrix resin.
[0060] The difference between Comparative Example 3 and Example 1 is that the amino resin was not added to the wave-absorbing layer. After the prepared non-woven fabric was subjected to wet heat aging treatment, the flexural strength of the non-woven fabric in Comparative Example 3 decreased significantly, and the heat resistance performance decreased significantly.
[0061] The difference between Comparative Example 4 and Example 1 is that the wave-absorbing material is carbon nanotubes, and the difference in the reflection loss value of the prepared non-woven fabric is increased. The wave absorption performance of the non-woven fabric with the introduction of high-entropy nanoalloy fiber is more excellent; at the same time, compared with Example 1, the peel strength and flexural strength have a significant decrease in performance, and the heat resistance performance decreases significantly.
[0062] Taking the above-described ideal embodiments of the present invention as an inspiration, through the above description, relevant staff can completely make various changes and modifications without departing from the technical idea of this invention. The technical scope of this invention is not limited to the content in the specification, and its technical scope must be determined according to the scope of the claims.
Claims
1. A method for preparing a high entropy nano alloy fiber absorbing material, characterized in that: The steps include: S1: dissolving the polymer in a mixed solvent of DMF and acetone to form a solution, adding five or more metal salts, and stirring at 60-80°C to obtain a spinning solution; S2: electrospinning the spinning solution to obtain a high entropy alloy nanofiber precursor; S3: pre-oxidizing the high entropy alloy nanofiber precursor at 220-240° C. in air, and then calcining at 800-900° C. to obtain a high entropy nano alloy fiber absorbing material.
2. The method for preparing the high entropy nano alloy fiber absorbing material according to claim 1, characterized in that: The polymer in step S1 is selected from at least one of polyacrylonitrile, polyvinylidene fluoride, polyimide, polymethyl methacrylate, and polystyrene.
3. The method for preparing the high entropy nano alloy fiber absorbing material according to claim 1, characterized in that: The metal salt is selected from at least one of nitrates, acetates, chlorides or sulfates of Au, Ag, Pt, Pd, Co, Mg, Ni, Cu, Zn, Mn, Sn, Mo, Ce or Fe.
4. A high entropy nano alloy fiber absorbing material, characterized in that: The high entropy nano alloy fiber absorbing material is prepared by the preparation method of the high entropy nano alloy fiber absorbing material as described in any one of claims 1 to 3.
5. A wave-absorbing non-woven fabric, characterized in that: It comprises two layers of non-woven fabric and an absorbing layer arranged between the two layers of the non-woven fabric; the absorbing layer comprises the high entropy nano alloy fiber absorbing material as claimed in claim 4.
6. The wave-absorbing non-woven fabric according to claim 5, characterized in that: The raw materials of the absorbing layer include the following components in parts by weight: 0.1~0.5 parts of high entropy nano alloy fiber absorbing material; 10-20 parts of organic solvent; 1~5 parts of modified flow agent; Phenolic resin 10-20 parts; 10-20 parts of amino resin.
7. The wave-absorbing non-woven fabric according to claim 6, characterized in that: The high entropy nano alloy fiber absorbing material is a high entropy nano alloy fiber that has been surface-modified; the high entropy nano alloy fiber that has been surface-modified is prepared according to the following method: the high entropy nano alloy fiber absorbing material is dispersed in ethanol, a low molecular weight organic polymer is added, stirred and reacted, and then dried to obtain the high entropy nano alloy fiber that has been surface-modified.
8. The wave-absorbing non-woven fabric according to claim 7, characterized in that: The organic polymer is selected from at least one of polyether polyol, polyester polyol, alcoholysed nylon, polyester modified acrylic resin, polyvinyl butyral, and butyraldehyde glycol acetal.
9. The wave-absorbing non-woven fabric according to claim 6, characterized in that: The organic solvent is selected from at least one of anhydrous ethanol, toluene, benzene, acetone and acrylic acid.
10. The wave-absorbing non-woven fabric according to claim 6, characterized in that: The modified flow agent is selected from at least one of terminal hydroxyl hyperbranched polyester, terminal carboxyl hyperbranched polyester, hyperbranched unsaturated resin, water-based chlorinated polypropylene emulsion, water-soluble epoxy resin emulsion, hyperbranched polyamide resin, and terminal amino hyperbranched polyamide.