Electromagnetic wave absorbing material and preparation method thereof

Abstract

The invention relates to an electromagnetic wave absorbing material and a preparation method of the electromagnetic wave absorbing material. The electromagnetic wave absorbing material comprises hollow spherical Fe3O4, liquid metal, and a first mixture formed by polydimethylsiloxane and a polydimethylsiloxane curing agent; the hollow spherical Fe3O4 is coated with the liquid metal to form a first composite material, and the mass ratio of the liquid metal to the hollow spherical Fe3O4 ranges from 5 wt% to 10 wt%; the first composite material is packaged in the first mixture, and the mass ratio of the first composite material to the first mixture is 7: 3. Through the electromagnetic wave absorbing material, the hollow spherical Fe3O4, the liquid metal and a heterogeneous interface between the hollow spherical Fe3O4 and the liquid metal, the effect of absorbing electromagnetic waves is improved.

Description

Technical Field

[0001] Embodiments of the present invention relate to the technical field of electromagnetic wave absorption, and in particular to an electromagnetic wave absorption material and a preparation method thereof. Background Art

[0002] With the rapid progress of wireless communication technologies, such as the widespread deployment of 5G and the Internet of Things (IoT), the speed and efficiency of information transmission have been significantly improved, thereby accelerating the pace of social intelligence. However, this has also brought about increasingly severe electromagnetic interference and radiation problems, which pose potential threats to human health and the stable operation of electronic devices. Electromagnetic interference may not only cause electronic device failures, affecting the accuracy and security of data transmission, but also have negative impacts on human health, such as causing health problems like headaches and insomnia.

[0003] To address these challenges, it is crucial to develop efficient electromagnetic wave absorption materials that can absorb or reflect excess electromagnetic waves, thereby reducing the secondary pollution of electromagnetic interference and radiation. Summary of the Invention

[0004] In view of the above problems, embodiments of the present invention provide an electromagnetic wave absorption material and a preparation method thereof, which overcome or at least partially solve the above problems.

[0005] According to one aspect of the embodiments of the present invention, there is provided an electromagnetic wave absorption material, which includes hollow spherical Fe3O4, liquid metal, and a first mixture formed by polydimethylsiloxane and a polydimethylsiloxane curing agent; the liquid metal coats the hollow spherical Fe3O4 to form a first composite material, and the mass ratio of the liquid metal to the hollow spherical Fe3O4 is between 5 wt% and 10 wt%; the first composite material is encapsulated in the first mixture, and the mass ratio of the first composite material to the first mixture is 7:3.

[0006] In an alternative embodiment, the liquid metal is a gallium-indium-tin alloy.

[0007] In an alternative embodiment, the first composite material has a core-shell structure.

[0008] In an alternative embodiment, the mass ratio of the polydimethylsiloxane to the polydimethylsiloxane curing agent is 8:1.

[0009] In an alternative embodiment, the mass ratio of the liquid metal to the hollow spherical Fe3O4 is 5 wt%.

[0010] According to one aspect of an embodiment of the present invention, there is provided a method for preparing an electromagnetic wave absorbing material, including: preparing hollow spherical Fe3O4; grinding and mixing the prepared hollow spherical Fe3O4 and liquid metal for a first preset time so that the liquid metal coats the hollow spherical Fe3O4 to obtain a first composite material, where the mass ratio of the liquid metal to the hollow spherical Fe3O4 is between 5 wt% and 10 wt%; mixing polydimethylsiloxane and a polydimethylsiloxane curing agent to form a first mixture; performing homogenization treatment on the first composite material and the first mixture, where the mass ratio of the first composite material to the first mixture is 7:3; and performing curing treatment on the first composite material and the first mixture after homogenization treatment to obtain the electromagnetic wave absorbing material.

[0011] In an alternative manner, the step of grinding and mixing the prepared hollow spherical Fe3O4 and liquid metal for a first preset time so that the liquid metal coats the hollow spherical Fe3O4 to obtain a first composite material includes sequentially placing the prepared hollow spherical Fe3O4 and the liquid metal in an agate mortar and grinding with an agate pestle for 20 min to obtain the first composite material.

[0012] In an alternative manner, the step of mixing polydimethylsiloxane and a polydimethylsiloxane curing agent to form a first mixture includes: stirring the polydimethylsiloxane and the polydimethylsiloxane curing agent at room temperature for 15 min to obtain the first mixture, where the mass ratio of the polydimethylsiloxane to the polydimethylsiloxane curing agent is 8:1.

[0013] In an alternative manner, the step of performing homogenization treatment on the first composite material and the first mixture includes: placing the first composite material and the first mixture in a homogenizer and performing homogenization treatment for 120 s, and the rotation speed of the homogenizer is 2000 r / min.

[0014] The beneficial effects of the embodiments of the present invention include providing an electromagnetic wave absorbing material, which includes hollow spherical Fe3O4, liquid metal, and a first mixture formed by polydimethylsiloxane and a polydimethylsiloxane curing agent; the liquid metal coats the hollow spherical Fe3O4 to form a first composite material, and the mass ratio of the liquid metal to the hollow spherical Fe3O4 is between 5wt% and 10wt%; the first composite material is encapsulated in the first mixture, and the mass ratio of the first composite material to the first mixture is 7:3. Through this electromagnetic wave absorbing material, on the one hand, the hollow spherical Fe3O4 can reduce impedance mismatch, so that more electromagnetic waves enter the interior of the electromagnetic wave absorbing material; on the other hand, the hollow spherical Fe3O4 is a magnetic material, which can achieve the effect of magnetic loss on electromagnetic waves; on the further hand, the liquid metal can perform dielectric loss on electromagnetic waves; on the still hand, the heterogeneous interface between the hollow spherical Fe3O4 and the liquid metal can provide interfacial polarization loss, further absorbing electromagnetic waves. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] One or more embodiments are exemplarily illustrated by the pictures in the corresponding drawings. These exemplary illustrations do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings are represented as similar elements. Unless otherwise stated, the drawings in the figures do not constitute a proportional limitation.

[0016] Figure 1 It is a schematic diagram of the electromagnetic wave absorbing material provided by the embodiments of the present invention.

[0017] Figure 2 It is a schematic flow chart of a preparation method of an electromagnetic wave absorbing material provided by the embodiments of the present invention.

[0018] The reference numerals in the drawings are as follows:

[0019] 100, electromagnetic wave absorbing material;

[0020] 10, hollow spherical Fe3O4; 20, liquid metal; 30, first mixture;

[0021] 1, first composite material. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0022] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0023] The embodiments of the present invention provide an electromagnetic wave absorbing material 100. Please refer to Figure 1, the electromagnetic wave absorbing material 100 includes hollow spherical Fe3O4 10, liquid metal 20, and a first mixture 30 formed by polydimethylsiloxane and a polydimethylsiloxane curing agent; the liquid metal 20 coats the hollow spherical Fe3O4 10 to form a first composite material 1, and the mass ratio of the liquid metal 20 to the hollow spherical Fe3O4 10 is between 5 wt% and 10 wt%; the first composite material 1 is encapsulated in the first mixture 30, and the mass ratio of the first composite material 1 to the first mixture 30 is 7:3. Through this electromagnetic wave absorbing material 100, on the one hand, the hollow spherical Fe3O4 10 can reduce impedance mismatch, so that more electromagnetic waves enter the interior of the electromagnetic wave absorbing material 100; on the other hand, the hollow spherical Fe3O4 is a magnetic material, which can achieve the effect of magnetic loss on electromagnetic waves; on the third hand, the liquid metal 20 can perform dielectric loss on electromagnetic waves; on the fourth hand, the heterogeneous interface between the hollow spherical Fe3O4 10 and the liquid metal 20 can provide interfacial polarization loss, further absorbing electromagnetic waves.

[0024] In some embodiments, the liquid metal 20 is a gallium indium tin alloy.

[0025] In some embodiments, the first composite material has a core-shell structure.

[0026] In some embodiments, the mass ratio of the polydimethylsiloxane to the polydimethylsiloxane curing agent is 8:1.

[0027] In some embodiments, the mass ratio of the liquid metal 20 to the hollow spherical Fe3O4 is 5 wt%. Through the reasonable setting of the mass ratio of the liquid metal 20 to the hollow spherical Fe3O4, the electromagnetic wave absorbing material not only exhibits excellent electromagnetic wave absorption performance but also has a relatively thin thickness.

[0028] According to one aspect of the embodiments of the present invention, please refer to Figure 2 , a method for preparing an electromagnetic wave absorbing material is provided, including:

[0029] Step S10, preparing hollow spherical Fe3O4.

[0030] Among them, the method for preparing hollow spherical Fe3O4 can be as follows: Dissolve the first mass of FeCl3·6H2O in the first volume of deionized water, and then add the second mass of C6H5O7Na3·2H2O and stir until completely dissolved. Then add the third mass of polyacrylamide and the fourth mass of urea, and stir for 1 h to obtain a uniform bright green solution. Place the obtained bright green solution in a high-pressure reaction kettle, heat it to 200 °C and react for 12 h. At the end of the reaction, wash the precipitate repeatedly with ethanol and deionized water alternately for 3 times, and place the precipitate in an oven at 100 °C and dry for 6 h to obtain hollow spherical Fe3O4.

[0031] Among them, the first mass of 1.3 g corresponds to the first volume of 100 ml; that is, the first mass of 2.6 g corresponds to the first volume of 200 ml;

[0032] Among them, the second mass is twice the first mass;

[0033] Among them, the first mass of 1.3 g corresponds to the third mass of 0.72 g; that is, the first mass of 2.6 g corresponds to the third mass of 1.44 g;

[0034] Among them, the third mass of 0.72 g corresponds to the fourth mass of 1.94 g; that is, the third mass of 1.44 g corresponds to the fourth mass of 3.88 g.

[0035] Specifically, an example of the method for preparing hollow spherical Fe3O4 is as follows: Dissolve 1.3 g of FeCl3·6H2O in 100 mL of deionized water, then add 2.6 g of C6H5O7Na3·2H2O and stir until completely dissolved. Then add 0.72 g of polyacrylamide and 1.94 g of urea, and stir for 1 h to obtain a uniform bright green solution. Place the obtained bright green solution in a high-pressure reaction kettle, heat it to 200 °C and react for 12 h. At the end of the reaction, wash the precipitate repeatedly with ethanol and deionized water alternately for 3 times, and place the precipitate in an oven at 100 °C and dry for 6 h to obtain hollow spherical Fe3O4.

[0036] Step S20, grind and mix the prepared hollow spherical Fe3O4 and the liquid metal for a first preset time so that the liquid metal coats the hollow spherical Fe3O4 to obtain a first composite material, and the mass ratio of the liquid metal to the hollow spherical Fe3O4 is between 5 wt% and 10 wt%.

[0037] In some embodiments, the step of grinding and mixing the prepared hollow spherical Fe3O4 and the liquid metal for a first preset time to coat the liquid metal on the hollow spherical Fe3O4 to obtain a first composite material includes sequentially placing the prepared hollow spherical Fe3O4 and the liquid metal in an agate mortar and grinding them with an agate pestle for 20 min to obtain the first composite material.

[0038] In some embodiments, the liquid metal is a gallium-indium-tin alloy.

[0039] In some embodiments, the formed first composite material has a core-shell structure.

[0040] Step S30: Mix polydimethylsiloxane and a polydimethylsiloxane curing agent to form a first mixture.

[0041] In some embodiments, the step of mixing polydimethylsiloxane and a polydimethylsiloxane curing agent to form a first mixture includes: stirring the polydimethylsiloxane and the polydimethylsiloxane curing agent at room temperature for 15 min to obtain the first mixture, wherein the mass ratio of the polydimethylsiloxane to the polydimethylsiloxane curing agent is 8:1.

[0042] Step S40: Homogenize the first composite material and the first mixture, wherein the mass ratio of the first composite material to the first mixture is 7:3.

[0043] In some embodiments, the step of homogenizing the first composite material and the first mixture includes: placing the first composite material and the first mixture in a homogenizer and performing homogenization for 120 s, and the rotation speed of the homogenizer is 2000 r / min.

[0044] Step S50: Cure the homogenized first composite material and the first mixture to obtain the electromagnetic wave absorbing material.

[0045] In some embodiments, the step of curing the homogenized first composite material and the first mixture to obtain the electromagnetic wave absorbing material includes: placing the homogenized first composite material and the first mixture in a mold and curing them in an oven at 100 °C for 6 h to obtain the electromagnetic wave absorbing material.

[0046] Among them, the mold can be made of polytetrafluoroethylene. The mold size can be 50 mm * 50 mm * 2 mm. After obtaining the electromagnetic wave absorbing material using the mold, the length and width of the sample can be cut according to different frequency bands.

[0047] To illustrate the beneficial effects of the electromagnetic wave absorbing material provided by the embodiments of the present invention, the applicant compared the electromagnetic wave absorbing materials in the prior art (the following comparative examples) with the electromagnetic wave absorbing materials included in the embodiments of the present invention or the electromagnetic wave absorbing materials prepared by using the preparation method of the electromagnetic wave absorbing material provided by the present invention (the following Example 1 and Example 2).

[0048]

Example 1

[0049] Prepare hollow spherical Fe3O4:

[0050] Dissolve 1.3 g of FeCl3·6H2O in 100 mL of deionized water, and then add 2.6 g of C6H5O7Na3·2H2O and stir until completely dissolved. Then add 0.72 g of polyacrylamide and 1.94 g of urea, and stir for 1 h to obtain a uniform bright green solution. Place the obtained bright green solution in a high-pressure reaction kettle and heat it to 200 °C for reaction for 12 h. At the end of the reaction, wash the precipitate repeatedly with ethanol and deionized water for 3 times, and place the precipitate in an oven at 100 °C for drying for 6 h to obtain hollow spherical Fe3O4.

[0051] Prepare the first composite material:

[0052] Weigh 20 g of hollow spherical Fe3O4 powder and place it in an agate mortar. Add 1.0 g (the mass ratio of the liquid metal to the hollow spherical Fe3O4 is 5 wt%) of liquid metal (gallium-indium-tin alloy), and grind it with an agate pestle for 20 min to obtain the first composite material.

[0053] Prepare the first mixture:

[0054] Stir 40 g of polydimethylsiloxane and 5 g of polydimethylsiloxane curing agent at room temperature for 15 min to obtain the first mixture.

[0055] Prepare the electromagnetic wave absorbing material:

[0056] Put 70 g of the first composite material and 30 g of the first mixture (the mass ratio of the first composite material to the first mixture is 7:3) into a homogenizer for homogenization treatment for 120 s, and the rotation speed of the homogenizer is 2000 r / min. Then place the homogenized first composite material and first mixture in a mold and place it in an oven at 100 °C for curing for 6 h to obtain the electromagnetic wave absorbing material.

[0057]

Example 2

[0058] The difference between Example 2 and Example 1 lies in the preparation of the first composite material: Weigh 20 g of hollow spherical Fe3O4 powder and place it in an agate mortar. Add 2.0 g of liquid metal (the mass ratio of the liquid metal to the hollow spherical Fe3O4 is 10 wt%), which is a gallium-indium-tin alloy. Grind it with an agate pestle for 20 minutes to obtain the first composite material.

[0059]

Comparative Example

[0060] Prepare hollow spherical Fe3O4: The same as in Example 1.

[0061] Prepare the first mixture: The same as in Example 1.

[0062] Prepare the electromagnetic wave absorbing material:

[0063] Put 70 g of hollow spherical Fe3O4 and 30 g of the first mixture (the mass ratio of the hollow spherical Fe3O4 to the first mixture is 7:3) into a homogenizer and perform homogenization treatment for 120 s. The rotation speed of the homogenizer is 2000 r / min. Then place the homogenized hollow spherical Fe3O4 and the first mixture in the same mold as in Example 1, and place it in an oven at 100 °C for curing for 6 h to obtain the electromagnetic wave absorbing material.

[0064] The applicant tested the thickness and reflection loss of the electromagnetic wave absorbing materials prepared in Example 1, Example 2, and the comparative example, as shown in Table 1 below:

[0065] Table 1

[0066]

[0067]

[0068] Among them, the reflection loss is an important parameter for evaluating the performance of the electromagnetic wave absorbing material. The larger the absolute value of the reflection loss, the better the absorption performance of the electromagnetic wave absorbing material for electromagnetic waves. It can be seen from the data in Table 1 that the electromagnetic wave absorbing materials prepared in Example 1 and Example 2 have higher reflection loss values compared with the comparative example, indicating that the electromagnetic wave absorbing material provided by the present invention has excellent electromagnetic wave absorption performance. In addition, in terms of the thickness of the electromagnetic wave absorbing material, compared with the comparative example, the electromagnetic wave absorbing materials of Example 1 and Example 2 provided by the present invention also have advantages.

[0069] In addition, by comparing Example 1 and Example 2, it can be seen that the mass ratio of the liquid metal to the hollow spherical Fe3O4 also has a certain influence on the performance of the electromagnetic wave absorbing material. The electromagnetic wave absorbing material in Example 1 has a thinner thickness, while the electromagnetic wave absorbing material in Example 2 has a higher reflection loss value and a slightly thicker thickness. This may be due to the increase in the liquid metal content. On the one hand, the hollow spherical Fe3O4 can reduce the impedance mismatch more, allowing more electromagnetic waves to enter the interior of the electromagnetic wave absorbing material. On the other hand, the hollow spherical Fe3O4 is a magnetic material, which can achieve the effect of magnetic loss for more electromagnetic waves. Additionally, the increase in the heterogeneous interface between the hollow spherical Fe3O4 and the liquid metal can provide more interfacial polarization loss, further absorbing the electromagnetic waves, thereby enhancing the absorption effect of the electromagnetic waves.

[0070] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Under the concept of the present invention, the technical features in the above embodiments or different embodiments can also be combined, and the steps can be implemented in any order. There are many other variations in different aspects of the present invention as described above, and for the sake of brevity, they are not provided in detail. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments or equivalently replace some of the technical features. However, such modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the various embodiments of the present invention.

Claims

1. An electromagnetic wave absorbing material, characterized in that, The electromagnetic wave absorbing material includes hollow spherical Fe3O4, liquid metal, and a first mixture formed by polydimethylsiloxane and a polydimethylsiloxane curing agent; The liquid metal coats the hollow spherical Fe3O4 to form a first composite material, and the mass ratio of the liquid metal to the hollow spherical Fe3O4 is between 5wt% and 10wt%; The first composite material is encapsulated in the first mixture, and the mass ratio of the first composite material to the first mixture is 7:

3.

2. The electromagnetic wave absorbing material according to claim 1, characterized in that, The liquid metal is a gallium-indium-tin alloy.

3. The electromagnetic wave absorbing material according to claim 1, wherein The first composite material has a core-shell structure.

4. The electromagnetic wave absorbing material according to claim 1, characterized in that, The mass ratio of the polydimethylsiloxane to the polydimethylsiloxane curing agent is 8:

1.

5. The electromagnetic wave absorbing material according to any one of claims 1-4, characterized in that, The mass ratio of the liquid metal to the hollow spherical Fe3O4 is 5wt%.

6. A preparation method of an electromagnetic wave absorbing material, characterized in that, Including: Preparing hollow spherical Fe3O4; Grinding and mixing the prepared hollow spherical Fe3O4 and liquid metal for a first preset time so that the liquid metal coats the hollow spherical Fe3O4 to obtain a first composite material, and the mass ratio of the liquid metal to the hollow spherical Fe3O4 is between 5wt% and 10wt%; Mixing polydimethylsiloxane and a polydimethylsiloxane curing agent to form a first mixture; Homogenizing the first composite material and the first mixture, wherein the mass ratio of the first composite material to the first mixture is 7:3; Performing a curing treatment on the homogenized first composite material and the first mixture to obtain the electromagnetic wave absorbing material.

7. The preparation method of the electromagnetic wave absorbing material according to claim 6, characterized in that, The step of grinding and mixing the prepared hollow spherical Fe3O4 and liquid metal for a first preset time so that the liquid metal coats the hollow spherical Fe3O4 to obtain a first composite material includes sequentially placing the prepared hollow spherical Fe3O4 and the liquid metal in an agate mortar and grinding with an agate pestle for 20 min to obtain the first composite material.

8. The preparation method of the electromagnetic wave absorbing material according to claim 6, wherein The step of mixing polydimethylsiloxane and a polydimethylsiloxane curing agent to form a first mixture includes: stirring the polydimethylsiloxane and the polydimethylsiloxane curing agent at room temperature for 15 min to obtain the first mixture, wherein the mass ratio of the polydimethylsiloxane to the polydimethylsiloxane curing agent is 8:

1.

9. The preparation method of the electromagnetic wave absorbing material according to claim 6, characterized in that, The step of homogenizing the first composite material and the first mixture includes: placing the first composite material and the first mixture in a homogenizer and performing homogenization for 120 s, and the rotation speed of the homogenizer is 2000 r / min.

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