A method for preparing polymer-based microwave absorbing material

Abstract

The present invention provides a method for preparing a polymer-based absorbing material, which comprises stacking and hot pressing a first sheet and a second sheet having a certain difference in absorbent content to form a unit sheet having a two-layer structure, and then evenly cutting the unit sheet into a plurality of sheets, and stacking and hot pressing the sheets in a periodic alternating order; after repeating the above steps for a plurality of times, a polymer-based absorbing material having a multi-interface parallel array structure is obtained. At the same time, the present invention also realizes the regulation of the conductive network of a single-layer conductive film in the material by changing the filling concentration of the absorbent and the thickness of each layer in the two-layer structural unit sheet. The above method is used to obtain an absorbing material having light weight, high strength, thin thickness, stable size, corrosion resistance, oxidation resistance, and excellent electromagnetic wave absorption performance, and the material has great application potential in electromagnetic protection technology for deep-sea ships and surface ships.

Description

Technical Field

[0001] The present invention relates to the technical field of electromagnetic wave protection for marine ship equipment, and in particular to a method for preparing a polymer-based wave-absorbing material. Background Art

[0002] With the advancement of marine ship technology and the widespread use of electronic equipment on ships, the threat posed by electromagnetic radiation to the health of crew members and the safety of ship equipment is becoming increasingly serious. In this context, the application of electromagnetic wave absorbing materials in naval and commercial ships has become particularly important. These materials can effectively absorb or reflect electromagnetic radiation, thereby protecting sensitive equipment on ships from interference, and also help reduce the impact on the health of crew members. Electromagnetic wave absorbing materials have been widely used in ship communication systems and navigation equipment, providing solid support for the development of deep-sea technology. The development of new electromagnetic wave absorbing materials specifically for marine ships has great academic significance and practical value, and has played a key role in promoting the development of modern marine engineering technology.

[0003] Materials based on polymers have become one of the mainstream research directions in the field of electromagnetic wave protection technology for marine ships in the future because of their characteristics of light weight, high strength, salt resistance, corrosion resistance, and easy processing. In the prior art, the patent document entitled "A polymer-based wave-absorbing foam material and its preparation method" with application number 202010432516.9 and publication date September 8, 2020, rolls the CNTs / PMMA nanocomposite material into a single-layer sheet by hot rolling, and then folds the single-layer sheet in half and rolls it again to obtain a laminated sheet. Then, the laminated sheet obtained in the previous step is repeatedly roll-to-roll hot rolled under the same conditions to obtain a multi-layer laminated sheet, and then foamed using supercritical fluid foaming technology. In the above technical scheme, a large number of interfaces are formed in the material by repeatedly rolling the sheet material to form a large number of interfaces in the material, so that after the subsequent foaming treatment, the pore size formed in the material can be smaller and the density can be higher. However, since the layered structures within the material have the same composition, each region within the material has the same effect on electromagnetic waves, and thus the material as a whole has poor electromagnetic wave absorption performance.

[0004] In view of this, it is necessary to design an improved method for preparing polymer-based absorbing materials to solve the above problems. Summary of the invention

[0005] The object of the present invention is to provide a method for preparing a polymer-based wave absorbing material.

[0006] To achieve the above-mentioned object of the invention, the present invention provides a method for preparing a polymer-based absorbing material, comprising the following steps:

[0007] S1, mixing a first polymer and a first absorber uniformly, then melt-kneading and hot-pressing, to obtain a first sheet; mixing a second polymer and a second absorber uniformly, then melt-kneading and hot-pressing, to obtain a second sheet;

[0008] S2, stacking and hot pressing the first sheet and the second sheet obtained in step S1 to form a unit sheet with a two-layer structure; evenly cutting the unit sheet into a plurality of secondary sheets, and alternately stacking and hot pressing all the secondary sheets in a certain periodic alternating order to obtain a sheet with an alternating structure; repeating the operations of evenly cutting, stacking and hot pressing the sheets with an alternating structure for a plurality of times to obtain a polymer-based absorbing material with a multi-interface parallel array structure.

[0009] Preferably, the thickness of the first sheet is 0.05-30 mm, and the mass percentage of the first absorber in the first sheet is 0-40%; preferably, the thickness of the second sheet is 0.05-30 mm, and the mass percentage of the second absorber in the second sheet is lower than that of the first sheet.

[0010] Preferably, in step S2, the thickness of the unit sheet with a two-layer structure is 0.05-20 mm; and the thickness of the polymer-based absorbing material is 0.05-10 mm.

[0011] Preferably, in step S2, the number of sheets obtained after each cutting is 2-20 sheets.

[0012] Preferably, in step S1, the first polymer and the second polymer are one or more of polymethyl methacrylate, polypropylene, polyethylene, polyaniline, polyurethane, polystyrene, polycarbonate, polyvinyl chloride, polyimide, polyethylene terephthalate, and polyacrylonitrile.

[0013] Preferably, in step S1, the first absorber and the second absorber are one or more of carbon nanotubes, graphene, carbon nanofibers, carbon black, graphite, and carbon fibers.

[0014] Preferably, in step S1, the hot pressing temperature is 120-280°C, the time is 20-90 min, and the pressure is 5-60 MPa.

[0015] Preferably, in step S2, the hot pressing temperature is 120-280°C, the time is 20-90 min, and the pressure is 5-60 MPa.

[0016] Preferably, in step S2, the method of stacking all the secondary sheets alternately in a periodic alternating order is: stacking the sheets according to the content of the absorber in the sheets.

[0017] Furthermore, the above preparation method can be used to prepare a polymer-based absorbing material, in which a multi-interface parallel array structure is formed.

[0018] The beneficial effects of the present invention are:

[0019] 1. The preparation method of the polymer-based absorbing material provided by the present invention is as follows: the method comprises stacking and hot pressing a first sheet and a second sheet having a certain difference in the content of the absorbing agent to form a unit sheet having a two-layer structure, and then evenly cutting the unit sheet into a plurality of sheets, and stacking and hot pressing them in a periodic alternating order; after repeating the above steps several times, a polymer-based absorbing material of a certain thickness is obtained. Through the above method, on the one hand, an absorption loss layer (a first sheet having a high content of the absorbing agent) and an electromagnetic wave impedance matching layer (a second sheet having a low content of the absorbing agent) can be introduced into the absorbing material to construct a multi-interface parallel array structure with a large performance difference in the absorbing material, thereby increasing the number of interfaces and improving the multiple reflection effect of electromagnetic waves at the interface between the layers inside the material. When the electromagnetic wave is reflected between the multi-layer matching layer and the loss layer structure, a micro-current phenomenon can occur, which promotes the attenuation of the electromagnetic wave, thereby giving the material better electromagnetic wave absorption performance; on the other hand, after stacking and hot pressing, the content of the absorbing agent can be kept constant, and the absorbing agent is selectively distributed to the electromagnetic wave impedance matching layer and the absorbing loss layer, thereby reducing the amount of the absorbing agent used as a whole.

[0020] 2. The preparation method of the polymer-based absorbing material provided by the present invention realizes the regulation of the conductive network of the single-layer conductive film in the material by changing the filling concentration of the absorber and the thickness of each layer in the two-layer structural unit sheet; the matching layer and the loss layer are stacked layer by layer to form an alternating multi-interface parallel array structure. While maintaining a certain content of the absorber in the unit volume, a multi-interface parallel array structure composed of a low-content absorber layer as an electromagnetic wave impedance matching layer and a high-content absorber layer as an electromagnetic wave absorption loss layer can be constructed inside the material, thereby promoting the impedance matching and absorption loss of the material, broadening the electromagnetic wave absorption bandwidth, and making the material have application prospects in marine environments. In summary, the multi-interface parallel array structure polymer-based absorbing material obtained by the preparation method provided by the present invention has excellent electromagnetic wave absorption performance.

[0021] 3. The preparation method of the polymer-based absorbing material provided by the present invention can be realized by simply cutting and hot pressing the sheet formed in the previous step several times after obtaining the unit sheet with a two-layer structure, so it has many advantages such as simple process, mild conditions, low cost, green and pollution-free. At the same time, the absorbing material prepared by the method proposed by the present invention has the advantages of light weight, high strength, thin thickness, stable size, corrosion resistance, oxidation resistance, and excellent electromagnetic wave absorption performance, and has great application potential in electromagnetic protection technology for deep-sea ships and surface ships. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The cross-sectional scanning electron microscope comparison diagram of the polymer-based absorbing materials prepared in Examples 1 to 6 of the present invention;

[0023] Figure 2 This is a schematic comparison diagram of the electromagnetic wave absorption performance of the polymer-based absorbing materials prepared in Examples 1-6 of the present invention. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] It should also be noted that, in order to avoid obscuring the present invention due to unnecessary details, only structures and / or processing steps closely related to the scheme of the present invention are shown in the drawings, while other details that are not closely related to the present invention are omitted.

[0026] In addition, it should be noted that the terms "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or apparatus.

[0027] The present invention provides a method for preparing a polymer-based microwave absorbing material, which specifically comprises the following steps:

[0028] S1, preparation of the first sheet and the second sheet: the first polymer and the absorber are mixed evenly, melt-kneaded and hot-pressed to obtain the first sheet; the second polymer and the absorber are mixed evenly, melt-kneaded and hot-pressed to obtain the second sheet;

[0029] S2. Preparation of polymer-based absorbing material: stacking and hot pressing the first sheet and the second sheet prepared in step S1 to form a unit sheet with a two-layer structure; evenly cutting the unit sheet into a plurality of secondary sheets, and alternately stacking and hot pressing all the secondary sheets in a certain periodic alternating order to obtain a sheet with an alternating structure; repeating the operations of evenly cutting, stacking and hot pressing the sheet with an alternating structure for several times to obtain a polymer-based absorbing material with a multi-interface parallel array structure.

[0030] Preferably, in step S1, the mass percentage of the absorber in the first sheet is 0-40%, and the mass percentage of the absorber in the second sheet is lower than that in the first sheet. More preferably, the mass percentage of the absorber in the first sheet is 4-8%. The thickness of the first sheet is 0.05-30 mm, and the thickness of the second sheet is 0.05-30 mm. In actual use, the first sheet and the second sheet can be adapted as needed to adjust the performance of the absorbing material. By preparing the absorbing material together with the first sheet and the second sheet having a certain difference in the content of the absorber, the excellent performance of the second sheet with a lower content of the absorber can be utilized. The electromagnetic wave impedance matching, together with the excellent lossiness of the first sheet material with a higher absorbent content, effectively improves the absorbency of the absorbing material. On the other hand, by using the first sheet material and the second sheet material with a large difference in absorbent content to prepare the absorbing material, the difference in composition between the two can be used to construct a multi-interface parallel array structure with a large difference in performance inside the absorbing material, thereby improving the multiple reflection effect of electromagnetic waves at the interface between layers inside the material. When the electromagnetic wave is reflected between the multi-layer matching layer and the loss layer structure, a microcurrent phenomenon can occur, which promotes the attenuation of the electromagnetic wave, thereby giving the material better electromagnetic wave absorption performance.

[0031] Preferably, in step S1, the hot pressing temperature is 120-280°C, the time is 20-90 min, and the pressure is 5-60 MPa.

[0032] Preferably, in step S1, the first polymer and the second polymer have the same source, and are one or more of polymethyl methacrylate (PMMA), polypropylene (PP), polyethylene (PE), polyaniline (PANI), polyurethane (PU), polystyrene (PS), polycarbonate (PC), polyvinyl chloride (PVC), polyimide (PI), polyethylene terephthalate (PET), and polyacrylonitrile (PAN); the first absorber and the second absorber are one or more of carbon-based conductive particle materials such as carbon nanotubes (CNTs), graphene, carbon nanofibers (CNFs), carbon black (CB), graphite, and carbon fiber (CF). .

[0033] Preferably, in step S2, the hot pressing temperature is 120-280°C, the time is 20-90 min, and the pressure is 5-60 MPa.

[0034] Preferably, in step S2, the thickness of the unit sheet with a two-layer structure is 0.05-20 mm; the thickness of the polymer-based absorbing material is 0.05-10 mm.

[0035] Preferably, in step S2, the number of sheets obtained after each cutting is 2-20 sheets.

[0036] Preferably, in step S2, the method of stacking all the secondary sheets alternately in a periodic alternating order is: stacking the sheets according to the content of the absorber therein, that is, the content of the absorber forms a distribution level of "high-low-high-low-...-high-low" or "low-high-low-high...-low-high" in the absorbing material. By the above setting of equally dividing the sheets and then stacking them, the absorber can be selectively distributed in each layer. At the same time, stacking the sheets with different absorber contents in a certain periodic order can reduce the content of the absorber in the whole material.

[0037] The polymer-based absorbing material proposed by the present invention is further described below in conjunction with specific embodiments:

[0038] Example 1

[0039] This embodiment prepares a polymer-based absorbing material, and the specific preparation method includes the following steps:

[0040] S1, using polymethyl methacrylate and carbon nanotubes to prepare a first sheet M1 of PMMA / CNTs nanocomposite material with a thickness of 20 mm, wherein the mass percentage of carbon nanotubes in the first sheet M1 is 4%; using polymethyl methacrylate and carbon black to prepare a second PMMA / CB sheet M2 with a thickness of 10 mm, wherein the mass percentage of carbon black in the second sheet M2 is 0.01%; wherein the first sheet M1 and the second sheet M2 are prepared by hot pressing, and the specific parameters of the hot pressing process are temperature 280°C, time 20min, and pressure 5MPa;

[0041] S2, stacking the first sheet M1 and the second sheet M2 obtained in step S1 together, and then hot pressing to obtain a unit sheet U1 with a two-layer structure of 20 mm in thickness; cutting the unit sheet U1 into 3 pieces of secondary sheets U2, and stacking and hot pressing all the secondary sheets in a certain periodic alternating order to obtain a sheet U3 with an alternating structure of 10 mm in thickness; cutting the sheet U3 with an alternating structure into 4 pieces, and stacking and hot pressing once to obtain a polymer-based absorbing material with a multi-layer structure of 2.5 mm in thickness. The parameters of hot pressing in this step are temperature 280°C, time 20min, and pressure 5MPa; the number of layers of the second sheet M2 in the polymer-based absorbing material is 12, and the number of layers of the first sheet M1 is 12.

[0042] Example 2

[0043] This embodiment prepares a polymer-based absorbing material, and the specific preparation method includes the following steps:

[0044] S1, using polyethylene and carbon nanotubes together to prepare a first sheet M1 of PE / CNTs nanocomposite material with a thickness of 15 mm, wherein the mass percentage of carbon nanotubes in the first sheet M1 is 5%; using polyethylene to prepare a second PE sheet M2 with a thickness of 5 mm; wherein the first sheet M1 and the second sheet M2 are prepared by hot pressing, and the specific parameters of the hot pressing process are temperature 120° C., time 90 min, and pressure 60 MPa;

[0045] S2, stacking the first sheet M1 and the second sheet M2 obtained in step S1 together, and then hot pressing to obtain a unit sheet U1 with a two-layer structure of 15 mm in thickness; cutting the unit sheet U1 into two secondary sheets, and stacking and hot pressing all the secondary sheets in a certain periodic alternating order to obtain a sheet U2 with an alternating structure of 10 mm in thickness; cutting the sheet U2 with an alternating structure into four pieces, and stacking and hot pressing twice to obtain a polymer-based absorbing material with a multi-layer structure of 2 mm in thickness. The number of layers of the second sheet M2 in the polymer-based absorbing material is 32, and the number of layers of the first sheet M1 is 32.

[0046] Example 3

[0047] This embodiment prepares a polymer-based absorbing material, and the specific preparation method includes the following steps:

[0048] S1, using polypropylene and carbon nanotubes to prepare a first sheet M1 of PP / CNTs nanocomposite material with a thickness of 10 mm, wherein the mass percentage of carbon nanotubes in the first sheet M1 is 6%; using polypropylene to prepare a second PP sheet M2 with a thickness of 6 mm; wherein the first sheet M1 and the second sheet M2 are prepared by hot pressing, and the specific parameters of the hot pressing process are temperature 210° C., time 20 min, and pressure 15 MPa;

[0049] S2, stacking the first sheet M1 and the second sheet M2 obtained in step S1 together, and then hot pressing to obtain a unit sheet U1 with a two-layer structure of 4 mm in thickness; evenly cutting the unit sheet U1 into 4 secondary sheets, and stacking and hot pressing all the secondary sheets in a certain periodic alternating order to obtain a sheet U4 with an alternating structure of 3 mm in thickness; evenly cutting the sheet U4 with an alternating structure into 4 pieces, and stacking and hot pressing twice to obtain a polymer-based absorbing material with a multi-layer structure of 2 mm in thickness. Among them, the number of layers of the second sheet M2 in the polymer-based absorbing material is 64, and the number of layers of the first sheet M1 is 64.

[0050] Example 4

[0051] This embodiment prepares a polymer-based absorbing material, and the specific preparation method includes the following steps:

[0052] S1, using polystyrene and carbon nanotubes to prepare a first sheet M1 of PS / CNTs nanocomposite material with a thickness of 1 mm, wherein the mass percentage of carbon nanotubes in the first sheet M1 is 8%; using polystyrene to prepare a second PS sheet M2 with a thickness of 7 mm; wherein the first sheet M1 and the second sheet M2 are prepared by hot pressing, and the specific parameters of the hot pressing process are temperature 180°C, time 35min, and pressure 20MPa;

[0053] S2, stacking the first sheet M1 and the second sheet M2 obtained in step S1 together, and then hot pressing to obtain a unit sheet U1 with a two-layer structure of 3.5 mm in thickness; cutting the unit sheet U1 into two secondary sheets, and stacking and hot pressing all the secondary sheets in a certain periodic alternating order to obtain a sheet U2 with an alternating structure of 2.5 mm in thickness; cutting the sheet U2 with an alternating structure into two pieces, and stacking and hot pressing once to obtain a polymer-based absorbing material with a multi-layer structure of 2 mm in thickness. The number of layers of the second sheet M2 in the polymer-based absorbing material is 4, and the number of layers of the first sheet M1 is 4.

[0054] Example 5

[0055] This embodiment prepares a polymer-based absorbing material, and the specific preparation method includes the following steps:

[0056] S1, using polyurethane and carbon nanotubes to prepare a first sheet M1 of PU / CNTs nanocomposite material with a thickness of 1 mm, wherein the mass percentage of carbon nanotubes in the first sheet M1 is 8%; using polyurethane to prepare a second PU sheet M2 with a thickness of 6 mm; wherein the first sheet M1 and the second sheet M2 are prepared by hot pressing, and the specific parameters of the hot pressing process are temperature 175° C., time 40 min, and pressure 25 MPa;

[0057] S2, stacking the first sheet M1 and the second sheet M2 obtained in step S1 together, and then hot pressing to obtain a unit sheet U1 with a two-layer structure of 3.5 mm in thickness; cutting the unit sheet U1 into 4 secondary sheets, and stacking and hot pressing all the secondary sheets in a certain periodic alternating order to obtain a sheet U4 with an alternating structure of 3 mm in thickness; cutting the sheet U4 with an alternating structure into 4 pieces, and stacking and hot pressing once to obtain a polymer-based absorbing material with a multi-layer structure of 2 mm in thickness. The number of layers of the second sheet M2 in the polymer-based absorbing material is 16, and the number of layers of the first sheet M1 is 16.

[0058] Example 6

[0059] This embodiment prepares a polymer-based absorbing material, and the specific preparation method includes the following steps:

[0060] S1, using polycarbonate and carbon nanotubes to prepare a first sheet M1 of PC / CNTs nanocomposite material with a thickness of 1 mm, wherein the mass percentage of carbon nanotubes in the first sheet M1 is 8%; using polycarbonate to prepare a second PC sheet M2 with a thickness of 6 mm; wherein the first sheet M1 and the second sheet M2 are prepared by hot pressing, and the specific parameters of the hot pressing process are temperature 170° C., time 45 min, and pressure 30 MPa;

[0061] S2, stacking the first sheet M1 and the second sheet M2 obtained in step S1 together, and then hot pressing to obtain a unit sheet U1 with a two-layer structure of 5 mm in thickness; cutting the unit sheet U1 into 4 secondary sheets, and stacking and hot pressing all the secondary sheets in a certain periodic alternating order to obtain a sheet U4 with an alternating structure of 5 mm in thickness; cutting the sheet U4 with an alternating structure into 4 sheets, and stacking and hot pressing twice to obtain a polymer-based absorbing material with a multi-layer structure of 2 mm in thickness. The number of layers of the second sheet M2 in the polymer-based absorbing material is 64, and the number of layers of the first sheet M1 is 64.

[0062] In order to fully understand the performance of the electromagnetic wave absorbing materials prepared in each embodiment, scanning electron microscope (SEM) test and vector network analysis test were carried out on them, and the results are as follows: Figure 1 and Figure 2 shown.

[0063] Depend on Figure 1 It can be seen that electromagnetic wave absorbing materials with multi-layer alternating structures can be prepared under different carbon nanotube contents, different polymer matrices, and different process conditions, and the boundaries between the various layer structures are clear. Figure 1 -a) forms a multi-interface parallel array structure in which PMMA layers and PMMA / CNTs layers alternate, the PMMA layer thickness ranges from 1 to 10 μm, and the PMMA / CNTs layer thickness ranges from 1 to 15 μm; Example 2 ( Figure 1 -b), Example 3 ( Figure 1 -c), Example 4 ( Figure 1 -d), Example 5 ( Figure 1 -e), Example 6 ( Figure 1 -f) The conclusion of the SEM analysis is similar to that of Example 1.

[0064] Depend on Figure 2It can be seen that the multi-interface parallel array structure materials prepared under different carbon nanotube contents, different polymer matrices and different process conditions all have good electromagnetic wave absorption performance. The minimum reflection losses of the multi-interface parallel array structure materials provided in Examples 1-6 in the range of 8.2-12.4GHz and 0.5-5mm thickness are -9.02dB ( Figure 2 -a)、-14.39dB( Figure 2 -b)、-18.92dB( Figure 2 -c)、-8.98dB( Figure 2 -d)、-9.69dB( Figure 2 -e)、-16.47dB( Figure 2 -f).

[0065] The above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention.

Claims

1. A method for preparing a polymer-based absorbing material, characterized in that: The steps include: S1. Mixing a first polymer and a first absorber uniformly, then melt-mixing and hot-pressing, to obtain a first sheet, wherein the mass percentage of the first absorber in the first sheet is 4%-8%; mixing a second polymer and a second absorber uniformly, then melt-mixing and hot-pressing, to obtain a second sheet; the hot-pressing temperature is 120° C.-280° C., the time is 20 min-90 min, and the pressure is 5 MPa-60 MPa; The mass percentage of the second absorber in the second sheet is lower than that in the first sheet, and the thickness of the first sheet is 1 mm-20 mm; the thickness of the second sheet is 5 mm-10 mm, the mass percentage of the second absorber is 0%-0.01%, and the thickness of the first sheet is different from that of the second sheet; The first polymer and the second polymer are one or more of polymethyl methacrylate, polypropylene, polyethylene, polyaniline, polyurethane, polystyrene, polycarbonate, polyvinyl chloride, polyimide, polyethylene terephthalate, and polyacrylonitrile; The first absorber and the second absorber are one or more of carbon nanotubes, graphene, carbon nanofibers, carbon black, graphite, and carbon fibers; S2, stacking and hot pressing the first sheet and the second sheet obtained in step S1 to form a unit sheet with a two-layer structure, the hot pressing temperature is 120°C-280°C, the time is 20min-90min, and the pressure is 5MPa-60MPa; the unit sheet is evenly cut into a plurality of secondary sheets, and all the secondary sheets are alternately stacked and hot pressed in a certain periodic alternating order to obtain a sheet with an alternating structure; the sheet with an alternating structure is subjected to repeated equal cutting and stacking and hot pressing operations for several times to obtain a polymer-based absorbing material with a multi-interface parallel array structure; The thickness of the unit sheet with a two-layer structure is 3.5 mm to 20 mm; the thickness of the polymer-based absorbing material is 2 mm to 2.5 mm.

2. The method for preparing a polymer-based absorbing material according to claim 1, characterized in that: In step S2, the number of sheets obtained after each cutting is 2 to 20 sheets.

3. The method for preparing a polymer-based absorbing material according to claim 1, characterized in that: In step S2, the method of stacking all the secondary sheets alternately in a periodic alternating order is: stacking the sheets according to the content of the absorber in the sheets.

4. A polymer-based absorbing material obtained by the preparation method according to any one of claims 1 to 3, characterized in that: A multi-interface parallel array structure is formed in the polymer-based absorbing material.

Images