Knittable magnetic fiber material with angle sensitive characteristic and preparation method and application thereof

Abstract

The invention discloses a knittable magnetic fiber material with an angle sensitive characteristic as well as a preparation method and application of the knittable magnetic fiber material. Cobalt acetate and nickel acetate are used as raw materials, under the alkaline condition, the magnetic fiber material of a CoNi single face-centered cubic crystal structure is prepared through solvothermal reaction under directional induction of a magnetic field, and the magnetic fiber material is in a long fiber shape with the smooth surface and has high orientation, angle sensitivity and weaving performance. According to the invention, the height orientation and the high length-diameter ratio of the magnetic fiber are realized through the oriented induction growth of the magnetic field, the magnetic anisotropy is obviously improved, and the material is endowed with angle-sensitive electromagnetic response. The shape of the magnetic fiber material is suitable for a weaving process, a fabric with functionality and certain flexibility can be prepared by combining conductive warp and weft materials, a woven body formed by weaving shows angle-dependent electromagnetic shielding and microwave thermal response performance, and the magnetic fiber material is suitable for the field of controllable electromagnetic protection and intelligent thermal management. And a new technical approach is provided for the development of flexible magnetic functional materials.

Description

Technical Field

[0001] This invention belongs to the field of magnetic materials and functional fiber technology, and particularly relates to a weavable magnetic fiber material with angle-sensitive characteristics, its preparation method, and its application in controllable electromagnetic shielding and microwave thermal conversion. Background Technology

[0002] With the rapid development of electronic devices, communication systems, and microwave technology, the electromagnetic environment is becoming increasingly complex. Electromagnetic interference and microwave radiation pose serious challenges to precision instruments, human health, and information security. Therefore, there is an urgent need for novel magnetic materials that combine lightweight, flexibility, and controllable microwave absorption and shielding functions. While traditional metal plates, carbon-based composites, and ferromagnetic powders possess absorption capabilities, they generally suffer from high density, poor flexibility, significant isotropy, and deficiencies in microwave-to-thermal energy conversion efficiency and controllability. In recent years, the introduction of magnetic nanoparticles or nanowires into polymer matrices has improved formability, but processes such as coating, impregnation, and electrospinning are often employed, requiring the incorporation of large amounts of polymers or other organic components. This leads to a decrease in the volume fraction of magnetic components, organic coating passivates the magnetic response, reduces saturation magnetization and magnetocaloric conversion efficiency, and affects long-term stability.

[0003] Meanwhile, composite fibers prepared by coating or impregnation are prone to problems such as surface aggregation of magnetic components, uneven interfacial bonding, and poor interlayer electromagnetic coupling. This results in unclear directionality of electromagnetic losses in multilayer structures, and the thermal response under microwave irradiation is often limited to the surface layer, making it difficult to form a controllable internal energy gradient, thus limiting the ability of localized heating and intelligent thermal management. It is worth noting that magnetic nanowires have the potential for magnetic anisotropy and angle sensitivity, but existing systems are mostly randomly oriented, making it difficult to achieve direction-dependent programmable responses on a macroscopic scale. Based on the above shortcomings, there is an urgent need to develop magnetic fibers with a single alloy phase, and to construct magnetic fiber materials with angle-sensitive characteristics through precise nano / micro-level orientation control, so as to achieve controllable electromagnetic shielding and efficient microwave thermal conversion, meeting the practical needs of flexible structural and functional applications. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a weavable magnetic fiber material with angle-sensitive characteristics, a method for preparing the same, and its application in controllable electromagnetic shielding and microwave thermal conversion.

[0005] To achieve the above objectives, the present invention provides the following technical solution;

[0006] In a first aspect, the present invention provides a braidable magnetic fiber material with angle-sensitive properties, wherein the magnetic fiber material is a single-phase CoNi alloy, is in the form of long fibers with a smooth surface, and has a high degree of orientation.

[0007] Furthermore, the magnetic fiber material is prepared by using cobalt acetate and nickel acetate as raw materials, under alkaline conditions, through a solvothermal reaction induced by a magnetic field.

[0008] Secondly, the present invention provides a method for preparing the above-mentioned angle-sensitive braidable magnetic fiber material, comprising the following steps:

[0009] S1. Mix cobalt acetate and nickel acetate, dissolve them in an organic solvent under alkaline conditions, and stir until homogeneous to form a uniform solution;

[0010] S2. The homogeneous solution obtained in S1 is transferred to a hydrothermal reactor and subjected to a solvothermal reaction under magnetic field induction to obtain magnetic fiber material.

[0011] Furthermore, in S1, the weight ratio of cobalt acetate to nickel acetate is 1:9 to 9:1.

[0012] Furthermore, in S1, the organic solvent is ethylene glycol.

[0013] Furthermore, in S1, the alkaline conditions are jointly regulated by sodium hydroxide and ethylenediamine, with the amount of sodium hydroxide added being 0.5-2 mol / L and the volume ratio of the amount of ethylenediamine added to the organic solvent being 1-10 mL: 20 mL.

[0014] Furthermore, in S2, the magnetic field-induced environment is achieved by placing ferrite magnets on both sides of the hydrothermal reactor. In this invention, the orientation and aspect ratio of the magnetic fiber material can be controlled by adjusting the magnetic field strength, direction, and magnet spacing of the magnetic field-induced environment. In one embodiment, the magnetic field-induced environment is achieved by placing ferrite magnets with a spacing of 10cm-20cm on both sides of the hydrothermal reactor.

[0015] Furthermore, in S2, the temperature of the solvothermal reaction is 150-250℃, and the reaction time is 12-24 hours. Of course, the reaction time of this invention can be adjusted appropriately according to the reaction conditions, as long as it does not affect the reaction process.

[0016] Thirdly, the present invention provides a woven body of magnetic fiber material, wherein the woven body uses the magnetic fiber material described in any one of the above claims to coat nano-silver fibers and twist them as weft, and nano-silver fibers as warp, and is woven by a loom to form a magnetic woven body with angle-sensitive characteristics.

[0017] Fourthly, the present invention provides the application of the magnetic fiber material described in any of the above claims and the braided body described above in controllable electromagnetic shielding and controllable microwave thermal conversion.

[0018] Beneficial effects:

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] (1) Improve magnetic anisotropy: This invention achieves high orientation and high aspect ratio of magnetic fibers through magnetic field directional induced growth, which significantly improves magnetic anisotropy and endows the material with angle-sensitive electromagnetic response.

[0021] (2) Strong weavability and flexibility: The magnetic fiber morphology provided by the present invention is suitable for weaving process. Combined with conductive warp and weft materials, it can be made into a fabric that is both functional and flexible, which is convenient for structural application.

[0022] (3) High efficiency microwave thermal conversion capability: The magnetic fiber provided by this invention is a CoNi long fiber, which can quickly and controllably convert electromagnetic energy into thermal energy under microwave field, making it suitable for selective heating and intelligent thermal management. Attached Figure Description

[0023] Figure 1 The appearance of the braidable magnetic fiber material prepared in Example 1;

[0024] Figure 2 SEM image of the braidable magnetic fiber material prepared in Example 1;

[0025] Figure 3 The X-ray diffraction pattern of the braidable magnetic fiber material prepared in Example 1;

[0026] Figure 4 The electromagnetic shielding performance of the braided magnetic fiber material prepared in Example 1 under test conditions of 0-180° and the proportion of electromagnetic wave absorption therein;

[0027] Figure 5 The temperature response of the braided magnetic fiber material prepared in Example 1 after microwave irradiation at 0-90° for 10 seconds;

[0028] Figure 6 The braided appearance of the braided magnetic fiber material prepared in Example 1;

[0029] Figure 7 The temperature response of the braided magnetic fiber material prepared in Example 2 after microwave irradiation at 0-90° for 10 seconds;

[0030] Figure 8 The temperature response of the braidable magnetic fiber material prepared in Example 3 after microwave irradiation at 0-90° for 10 seconds;

[0031] Figure 9 SEM images of the product were obtained for Comparative Example 1. Specific implementation methods

[0032] The present invention will now be described with reference to the accompanying drawings and embodiments. However, the embodiments described are for illustrative purposes only and do not limit the scope of protection of the present invention.

[0033] Unless otherwise stated, the terms and values ​​used herein shall be understood in accordance with the common understanding of those skilled in the art. The term "and / or" indicates that any of the listed items or any combination thereof may be used alone; "optional" indicates that the item is optional, and each "optional" item is independent of the others in the absence of conflict. Features listed in an open enumeration can be understood as either a closed combination or a broader range including the listed features. Numerical ranges are considered continuous and include endpoints unless otherwise specified, and integer ranges include all integers therein; different ranges may be merged, and any upper or lower limit may be combined to form a new range not explicitly stated. Temperature parameters may be constant temperature or range control, allowing for small fluctuations within the instrument's accuracy range (e.g., ±5°C). Terms such as "including / comprise" are non-limiting and allow for the addition of other steps or components that do not change the technical effect. "Multiple" in this document refers to at least two. All embodiments, options, and steps may be combined with each other or implemented in any order (preferably in the order of description) unless otherwise specified. The ferrite magnets used in the embodiments of this invention are conventional ferrite magnets with a surface magnetic field strength of 300-1900G.

[0034] The foregoing description is intended to explain the present invention, but does not limit the scope of protection of its claims. All equivalent substitutions or improvements made under the inventive concept should be covered within the scope of protection of the present invention.

[0035] Example 1

[0036] First, 0.4 g of cobalt acetate, 0.1 g of nickel acetate, 3 g of sodium hydroxide, and 6.5 mL of ethylenediamine were dissolved in 40 mL of ethylene glycol and stirred at 60 °C for 15 minutes to form a homogeneous solution. Next, the resulting solution was transferred to a hydrothermal reactor, and magnets were placed on both sides of the reactor at a distance of 15 cm. The reactor was then reacted at 200 °C for 24 hours. Finally, the reaction product was cooled to room temperature, and the resulting braidable magnetic fibers were collected. The collected braidable magnetic fibers were then coated with silver nanofibers and twisted to serve as the weft, while the silver nanofibers served as the warp. The fibers were then woven on a loom at predetermined angles and with a predetermined weave to form an angle-sensitive magnetic braid.

[0037] Example 2

[0038] Compared with Example 1, the operation is basically the same, except that the amount of sodium hydroxide added is changed to 2g, the hydrothermal reaction temperature is 220℃, the magnet spacing is 20cm, and the reaction time is 20 hours.

[0039] Example 3

[0040] Compared with Example 1, the operation is basically the same, the only difference is that the weaving process is omitted, and only the magnetic fiber product is prepared for characterization and performance testing.

[0041] The microstructure of the magnetic fibers obtained in the above embodiments was characterized by scanning tunneling microscopy (SEM, Hitachi S-4800); X-ray diffraction patterns were determined using a Bruker D8 Advance instrument; and electromagnetic shielding data were tested in the frequency range of 8.2-12.4 GHz using a vector network analyzer of model N5230C.

[0042] Figure 1 The appearance of the braidable magnetic fiber material prepared in Example 1 shows that it is generally a long fiber with a smooth surface.

[0043] Figure 2 The image shows a scanning electron microscope (SEM) image of the braidable magnetic fiber material prepared in Example 1. The microstructure shows that the material is composed of long fibers with a smooth surface and a chain diameter of 3 micrometers, exhibiting a high aspect ratio and orientation.

[0044] Figure 3 The X-ray diffraction (XRD) analysis of the braidable magnetic fiber material prepared in Example 1 shows a face-centered cubic alloy peak shape, indicating that the prepared magnetic fiber has a CoNi single face-centered cubic crystal structure.

[0045] Figure 4 The electromagnetic shielding performance of the braided magnetic fiber prepared in Example 1 under test conditions of 0-180° and the proportion of electromagnetic wave absorption therein are shown. The electromagnetic shielding performance in the range of 0-90° changes linearly with the test angle, which proves the angle-sensitive and controllable electromagnetic shielding performance.

[0046] Figure 5 The temperature response of the braided magnetic fiber prepared in Example 1 after microwave irradiation at 0-90° for 10s is shown. The results indicate that the temperature of the braid changes significantly with the angle, demonstrating the angle-sensitive and controllable microwave thermal conversion performance.

[0047] Figure 6 The appearance of the braided magnetic fiber prepared in Example 1 shows that the surface of the braid is flat, without fiber breakage or disordered accumulation, and the macroscopic orientation characteristics of the fibers along a specific direction are visible to the naked eye, without obvious wrinkles or rigid breaks.

[0048] Figure 7 The temperature response of the braided magnetic fiber prepared in Example 2 after microwave irradiation at 0-90° for 10s is shown. The results show that the temperature of the braid changes significantly with the angle, proving the angle-sensitive and controllable microwave thermal conversion performance.

[0049] Figure 8 The temperature response of the braidable magnetic fiber prepared in Example 3 after microwave irradiation at 0-90° for 10s is shown. The results indicate that the temperature of the prepared magnetic fiber changes significantly with the angle, demonstrating the angle-sensitive and controllable microwave thermal conversion performance.

[0050] Comparative Example 1

[0051] The operation is basically the same as in Example 1, except that the magnetic field induction is omitted (no ferrite magnet is placed).

[0052] Figure 9 The image shown is a SEM image of the product obtained in Comparative Example 1. Compared to Example 1, it cannot grow highly oriented long fibers and exhibits a structure with many branches and no obvious orientation. This comparative example further demonstrates the crucial role of magnetic field orientation induction in the growth and orientation formation of long fibers.

[0053] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A weavable magnetic fiber material with angle-sensitive properties, characterized in that, The magnetic fiber material has a CoNi single-face-centered cubic crystal structure, is in the form of long fibers with smooth surfaces, and has a high degree of orientation.

2. The magnetic fiber material according to claim 1, characterized in that, The magnetic fiber material is prepared by using cobalt acetate and nickel acetate as raw materials, under alkaline conditions, through a solvothermal reaction induced by a magnetic field.

3. The method for preparing the magnetic fiber material according to any one of claims 1 to 2, characterized in that, Includes the following steps: S1. Mix cobalt acetate and nickel acetate, dissolve them in an organic solvent under alkaline conditions, and stir until homogeneous to form a uniform solution; S2. The homogeneous solution obtained in S1 is transferred to a hydrothermal reactor and subjected to a solvothermal reaction under magnetic field induction to obtain magnetic fiber material.

4. The method according to claim 3, characterized in that, In S1, the weight ratio of cobalt acetate to nickel acetate is 1:9 to 9:

1.

5. The method according to claim 3, characterized in that, In S1, the organic solvent is ethylene glycol.

6. The method according to claim 3, characterized in that, In S1, the alkaline conditions are jointly controlled by sodium hydroxide and ethylenediamine. The amount of sodium hydroxide added is 0.5-2 mol / L, and the volume ratio of ethylenediamine added to organic solvent is 1-10 mL: 20 mL.

7. The method according to claim 3, characterized in that, In S2, the magnetic field induced environment is achieved by placing ferrite magnets on both sides of the hydrothermal reactor, with a magnet spacing of 10cm-20cm.

8. The method according to claim 3, characterized in that, In S2, the temperature of the solvothermal reaction is 150-250℃, and the reaction time is 12-24h.

9. A braided structure of magnetic fiber material, characterized in that, The braided body uses the magnetic fiber material described in any one of claims 1 to 2, coated with nano-silver fibers and twisted, as the weft, and nano-silver fibers as the warp, and is woven by a loom to form a magnetic braided body with angle-sensitive characteristics.

10. The application of the magnetic fiber material according to any one of claims 1 to 2 and the braid according to claim 9 in controllable electromagnetic shielding and controllable microwave thermal conversion.

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