Preparation method of porous wave-absorbing material

Abstract

This application discloses a method for preparing a porous microwave absorbing material, comprising the following steps: mixing a polymeric monomer material, an initiator, and a nano-conductive filler for a prepolymerization reaction; adding a crosslinking agent and an emulsifier to the prepolymerized mixture to obtain an organic phase; preparing an aqueous phase and adding the aqueous phase to the organic phase while stirring to obtain a polymer emulsion; and polymerizing the polymer emulsion to obtain the porous microwave absorbing material. This preparation method can improve the dispersion of the conductive filler, obtain polymers with higher molecular weights, and solve the defect in traditional porous materials where inorganic conductive fillers cannot be fixedly dispersed in the organic phase and migrate into the aqueous solution.

Description

Technical Field

[0001] This application relates to the field of materials preparation technology, and in particular to a porous polymer material with microwave absorption properties, its preparation method, and its application. Background Technology

[0002] Porous polymer materials are lightweight and flexible porous materials. Due to their internal pore structure, they exhibit better adsorption properties, higher specific surface area, and greater mechanical stability compared to traditional porous materials, and are commonly used in filtration, insulation, acoustics, optoelectronics, and other fields. Traditional methods for preparing porous polymers mainly include reverse phase methods, phase separation methods, and solvent-induced pore methods. However, these methods cannot precisely control the size and distribution of pores and channels, and the polymer porous materials with interconnected pore structures prepared so far generally have poor mechanical properties, exhibiting high brittleness and a tendency to pulverize.

[0003] Styrene is highly hydrophobic and can form relatively stable emulsions with water under the action of emulsifiers. The surface morphology of the porous materials formed after polymerization is easy to control, which has attracted the research interest of many scientists abroad. However, most polystyrene foams prepared by existing methods are wave-transparent foams, which cannot be used in special fields such as electromagnetic shielding that require wave absorption. Therefore, the research and development of wave-absorbing porous foam materials is still of great significance. Summary of the Invention

[0004] To address the aforementioned problems, the purpose of this application is to provide a porous polymer material with microwave absorption properties and high mechanical energy, and a method for preparing the same.

[0005] Specifically, this application provides a method for preparing a porous microwave absorbing material, which includes:

[0006] The monomer material, initiator, and nano-conductive filler are mixed and subjected to a prepolymerization reaction.

[0007] Adding a crosslinking agent and an emulsifier to the mixture after the prepolymerization reaction yields an organic phase.

[0008] Prepare an aqueous phase by adding it to the organic phase and stirring to obtain a polymer emulsion.

[0009] The porous microwave absorbing material is obtained by polymerizing the polymer emulsion.

[0010] Furthermore, the polymeric monomer is one or more of styrene, methyl methacrylate, methyl acrylate, and ethyl acrylate.

[0011] Furthermore, the initiator is selected from azo initiators or peroxide initiators.

[0012] More preferably, the initiator is selected from one or more of azobisisobutyronitrile, azobisisoheptanenitrile, benzoyl peroxide, di-tert-butyl peroxide, and cumene hydroperoxide.

[0013] Furthermore, the nano-conductive filler is selected from one or more of carbon black, carbon nanotubes, carbon fibers, metal nanomaterials, and metal nanowires.

[0014] More preferably, the nano-conductive filler is selected from carbon black or carbon nanotubes.

[0015] Furthermore, in the prepolymerization reaction, the mass ratio of the polymer monomer material, the initiator, and the nano-conductive filler is 50-80:0.1-5:5-15.

[0016] Furthermore, the temperature of the prepolymerization reaction is 50-80℃, and the prepolymerization time is 10-20 min.

[0017] Furthermore, the crosslinking agent is selected from one or more of ethylene glycol dimethacrylate, divinylbenzene, triallyl cyanurate, and pentaerythritol triacrylate.

[0018] More preferably, the crosslinking agent is divinylbenzene.

[0019] Furthermore, the emulsifier is selected from one or more of span20, span80, DDBSS, CATB and Hypermer1070.

[0020] More preferably, the emulsifier is Span80.

[0021] Furthermore, by mass fraction, the organic phase comprises 50-80% polymeric monomer material, 0.1-5% initiator, 5-15% nano-conductive filler, 10-25% crosslinking agent, and 5-15% emulsifier.

[0022] Furthermore, the aqueous phase is an aqueous solution of calcium chloride.

[0023] More preferably, the concentration of the calcium chloride aqueous solution is 5-25 g / L.

[0024] Furthermore, the stirring rate is 300-1000 rpm.

[0025] Furthermore, the polymerization temperature is 50-80°C.

[0026] Furthermore, the reaction time for the polymerization is 24-120 h.

[0027] Furthermore, in the prepared polymer emulsion, the weight ratio of the organic phase to the aqueous phase is 15-30:70-85.

[0028] This application also provides a porous absorbing material prepared by the aforementioned preparation method.

[0029] Furthermore, the density of the porous absorbing material is 200-300 kg / m³. 3 The porosity is 70%-85%.

[0030] This application also provides the application of the porous absorbing material in the fields of electronic and electrical electromagnetic shielding materials and aerospace.

[0031] The effects of the invention

[0032] The porous microwave absorbing material provided in this application combines porous materials with nano-conductive fillers, which not only improves the mechanical properties of the porous material but also endows it with new microwave absorption functions. In the preparation method, on the one hand, an oil-in-water (W / O) emulsion is used, with an oil-soluble composite monomer and an electrolyte aqueous solution as the continuous phase and dispersed phase, respectively, resulting in a highly stable emulsion. The W / O emulsion has a high-viscosity oil as the external phase and water as the internal phase, resulting in poor droplet flow and minimal aggregation. Furthermore, the water removal process does not cause resource waste or environmental pollution, thus exhibiting good stability and making the preparation process more environmentally friendly. On the other hand, inorganic conductive fillers are integrated into the polymer aggregate during the preparation process. Pre-reaction with the polymer monomer yields a linear polymer with grafted inorganic fillers of a certain viscosity. This improves the dispersion of the inorganic fillers and allows for the production of polymers with higher molecular weights. It also solves the problem in traditional porous materials where inorganic conductive fillers cannot be fixedly dispersed within the organic phase and migrate into the aqueous solution. Detailed Implementation

[0033] The present application will now be described in further detail with reference to specific embodiments. The embodiments given are intended to enable a more thorough understanding of the present application and to fully convey the scope of the present application to those skilled in the art.

[0034] It should be noted that the terms "comprising" or "including" used throughout the specification and claims are open-ended terms and should be interpreted as "comprising but not limited to". The subsequent descriptions in the specification are preferred embodiments for carrying out this application; however, these descriptions are for the purpose of understanding the general principles of the specification and are not intended to limit the scope of this application. The scope of protection of this application shall be determined by the appended claims.

[0035] This application relates to a method for preparing a porous microwave absorbing material, the method comprising:

[0036] The monomer material, initiator, and nano-conductive filler are mixed and subjected to a prepolymerization reaction.

[0037] Adding a crosslinking agent and an emulsifier to the mixture after the prepolymerization reaction yields an organic phase.

[0038] Prepare an aqueous phase by adding it to the organic phase and stirring to obtain a polymer emulsion.

[0039] The porous microwave absorbing material is obtained by polymerizing the polymer emulsion.

[0040] The polymer emulsion described in this application is a water-in-oil (W / O) type polymer emulsion, with an oil-soluble monomer (polymer phase) as the continuous phase and an aqueous phase as the dispersed phase. This polymer emulsion can be used to prepare porous polymers via an emulsion module method, utilizing the droplet structure of the emulsion as a template to prepare materials with specific morphologies and structures. Under certain conditions, a polymerization reaction is carried out to polymerize the continuous phase, and after washing and drying, a porous polymer with controllable pore size and distribution is obtained.

[0041] In a specific embodiment, the polymeric monomer is one or more of styrene, methyl methacrylate, methyl acrylate, and ethyl acrylate.

[0042] In a preferred embodiment, the polymeric monomer is styrene.

[0043] The preparation method described in this application is applicable to various types of porous materials, such as polymethyl methacrylate-based porous materials, organosilicon polystyrene porous materials, and polyethersulfone porous materials. In specific embodiments, the appropriate polymer monomer can be selected according to the specific material.

[0044] In a specific embodiment, the initiator is selected from azo initiators or peroxide initiators.

[0045] In some preferred embodiments, the initiator is selected from one or more of azobisisobutyronitrile, azobisisoheptanenitrile, benzoyl peroxide, di-tert-butyl peroxide, and cumene hydroperoxide.

[0046] In a specific embodiment, the nano-conductive filler is selected from one or more of carbon black, carbon nanotubes, carbon fibers, metal nanomaterials, and metal nanowires.

[0047] In some preferred embodiments, the nano-conductive filler is carbon black or carbon nanotubes.

[0048] In a specific embodiment, during the prepolymerization reaction, the mass ratio of the polymerizable monomer material, initiator, and nano-conductive filler is 50-80:0.1-5:5-15. For example, the mass ratio of the polymerizable monomer material, initiator, and nano-conductive filler is 50 or 55 or 60 or 65 or 70 or 75 or 80:0.1 or 0.5 or 1 or 1.5 or 2 or 2.5 or 3 or 3.5 or 4 or 4.5 or 5:5 or 6 or 7 or 8 or 9 or 10 or 11 or 12 or 13 or 14 or 15.

[0049] In a specific embodiment, the polymerizable monomer material, initiator, and nano-conductive filler are mixed according to the above-mentioned mass ratio, and a prepolymerization reaction is carried out at a temperature of 50-80°C, for example, 50, 55, 60, 65, 70, 75, or 80°C, and the prepolymerization reaction time is 10-20 min, for example, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 min.

[0050] In a specific embodiment, a crosslinking agent and an emulsifier are further added to the mixture obtained after prepolymerization to obtain an organic phase.

[0051] In a specific embodiment, the crosslinking agent is divinylbenzene.

[0052] In a specific embodiment, the emulsifier is selected from one or more of span20, span80, DDBSS, CATB and Hypermer1070.

[0053] In some preferred embodiments, the emulsifier is Span80.

[0054] In a specific embodiment, by mass parts, the formed organic phase contains 50-80% polymeric monomer material, 0.1-5% initiator, 5-15% nano-conductive filler, 10-25% crosslinking agent, and 5-15% emulsifier.

[0055] In one specific embodiment, the organic phase comprises the following components:

[0056]

[0057] In a specific implementation, the aqueous phase is an aqueous solution of calcium chloride.

[0058] In some specific embodiments, the concentration of the calcium chloride aqueous solution is 5-25 g / L, for example, 5, 10, 15, 20, or 25 g / L.

[0059] In a specific embodiment, an aqueous phase is added to an organic phase to obtain a polymer emulsion.

[0060] In some preferred embodiments, the aqueous phase is slowly added to the organic phase at a constant rate.

[0061] In some specific implementations, stirring is performed simultaneously with or after the addition of the aqueous phase to the organic phase.

[0062] In some specific embodiments, the stirring rate is 300-1000 rpm.

[0063] In some specific embodiments, the stirring continues for 5-10 minutes after the aqueous solution has been added.

[0064] In a specific embodiment, the weight ratio of the organic phase to the aqueous phase in the polymer emulsion is 15-25:75-85, for example, 15:85, 18:82, 20:80, 22:78 or 25:75.

[0065] In a specific embodiment, the polymer emulsion is added and polymerized to obtain the porous microwave absorbing material.

[0066] In some specific embodiments, the polymerization reaction temperature is 50-80°C and the polymerization reaction time is 24-120h.

[0067] In some specific embodiments, the preparation method further dries the obtained material after polymerization is completed.

[0068] This application also relates to a porous microwave absorbing material prepared by the above-described preparation method.

[0069] In a specific embodiment, the density of the porous absorbing material is 200-300 kg / m³. 3 The porosity is 70%-85%.

[0070] This application also relates to the application of the aforementioned porous absorbing materials in the field of electromagnetic shielding materials.

[0071] Example

[0072] This application provides a general and / or specific description of the materials and test methods used in the experiments. In the following examples, unless otherwise specified, % represents wt%, i.e., weight percentage. All reagents or instruments used, unless otherwise specified, are commercially available conventional reagent products or conventional laboratory instruments.

[0073] Example 1: Preparation of porous absorbing materials

[0074] (1) Add 70g of polymer monomer (styrene), 1.3g of initiator (azobisisobutyronitrile), and 8g of nano-conductive filler (carbon black) to the reactor and carry out a prepolymerization reaction at 70℃ for 15min;

[0075] (2) Add 15g of crosslinking agent (divinylbenzene) and 8g of emulsifier (span80) to the prepolymer obtained in the above steps to obtain an organic phase;

[0076] (3) Prepare 300g of calcium chloride aqueous solution with a concentration of 18g / L, add it to the above organic phase at a rate of 700rpm, and stir for 5-10 minutes to obtain a polymer emulsion;

[0077] (4) The polymer emulsion from the previous step is heated at 60°C for 105 hours and then dried to obtain a porous microwave absorbing material.

[0078] Example 2: Preparation of porous absorbing materials

[0079] (1) Add 70g of polymer monomer (styrene), 1.3g of initiator (azobisisobutyronitrile), and 8g of nano-conductive filler (carbon black) to the reactor and carry out a prepolymerization reaction at 70℃ for 15min;

[0080] (2) Add 15g of crosslinking agent (divinylbenzene) and 8g of emulsifier (span80) to the prepolymer obtained in the above steps to obtain an organic phase;

[0081] (3) Prepare 560g of calcium chloride aqueous solution with a concentration of 18g / L, add it to the above organic phase at a rate of 700rpm, and stir for 5-10 minutes to obtain a polymer emulsion;

[0082] (4) The polymer emulsion from the previous step is heated at 60°C for 105 hours and then dried to obtain a porous microwave absorbing material.

[0083] Example 3: Preparation of porous absorbing materials

[0084] (1) Add 70g of polymer monomer (styrene), 1.3g of initiator (azobisisobutyronitrile), and 5g of nano-conductive filler (carbon black) to the reactor and carry out a prepolymerization reaction at 70℃ for 15min;

[0085] (2) Add 15g of crosslinking agent (divinylbenzene) and 8g of emulsifier (span80) to the prepolymer obtained in the above steps to obtain an organic phase;

[0086] (3) Prepare 300g of calcium chloride aqueous solution with a concentration of 18g / L, add it to the above organic phase at a rate of 700rpm, and stir for 5-10 minutes to obtain a polymer emulsion;

[0087] (4) The polymer emulsion from the previous step is heated at 60°C for 105 hours and then dried to obtain a porous microwave absorbing material.

[0088] Example 4: Preparation of porous absorbing materials

[0089] (1) Add 70g of polymer monomer (styrene), 1.3g of initiator (azobisisobutyronitrile), and 10g of nano-conductive filler (carbon black) to the reactor and carry out a prepolymerization reaction at 70℃ for 15min;

[0090] (2) Add 15g of crosslinking agent (divinylbenzene) and 8g of emulsifier (span80) to the prepolymer obtained in the above steps to obtain an organic phase;

[0091] (3) Prepare 300g of calcium chloride aqueous solution with a concentration of 18g / L, add it to the above organic phase at a rate of 700rpm, and stir for 5-10 minutes to obtain a polymer emulsion;

[0092] (4) The polymer emulsion from the previous step is heated at 60°C for 105 hours and then dried to obtain a porous microwave absorbing material.

[0093] Example 5: Preparation of porous absorbing materials

[0094] (1) Add 60g of polymer monomer (styrene), 3g of initiator (azobisisobutyronitrile), and 15g of nano-conductive filler (carbon black) to the reactor and carry out a prepolymerization reaction at 70℃ for 15min.

[0095] (2) Add 10g of crosslinking agent (divinylbenzene) and 10g of emulsifier (span80) to the prepolymer obtained in the above steps to obtain an organic phase;

[0096] (3) Prepare 300g of calcium chloride aqueous solution with a concentration of 13g / L, add it to the above organic phase at a rate of 700rpm, and stir for 5-10 minutes to obtain a polymer emulsion;

[0097] (4) The polymer emulsion from the previous step is heated at 60°C for 105 hours and then dried to obtain a porous microwave absorbing material.

[0098] Comparative Example 1

[0099] (1) Add 70g of polymer monomer (styrene), 1.3g of initiator (azobisisobutyronitrile), and 8g of nano-conductive filler (carbon black) to the reactor and carry out a prepolymerization reaction at 90℃ for 30min;

[0100] (2) Add 15g of crosslinking agent (divinylbenzene) and 8g of emulsifier (span80) to the prepolymer obtained in the above steps to obtain an organic phase;

[0101] (3) Prepare 300g of calcium chloride aqueous solution with a concentration of 18g / L, add it to the above organic phase at a rate of 700rpm, and stir for 5-10 minutes to obtain a polymer emulsion;

[0102] (4) The polymer emulsion from the previous step is heated at 60°C for 105 hours and then dried to obtain a porous microwave absorbing material.

[0103] Comparative Example 2

[0104] (1) 70g of polymer monomer (styrene), 1.3g of initiator (azobisisobutyronitrile), 8g of nano-conductive filler (carbon black), 15g of crosslinking agent (divinylbenzene), and 8g of emulsifier (span80) were added to the reactor to obtain the organic phase;

[0105] (2) Prepare 300g of calcium chloride aqueous solution with a concentration of 18g / L, add it to the above organic phase at a rate of 700rpm, and stir for 5-10 minutes to obtain a polymer emulsion;

[0106] (3) The polymer emulsion from the previous step is heated at 60°C for 105 hours and then dried to obtain a porous microwave absorbing material.

[0107] Comparative Example 3

[0108] (1) Add 70g of polymer monomer (styrene), 1.3g of initiator (azobisisobutyronitrile), and 3g of nano-conductive filler (carbon black) to the reactor and carry out a prepolymerization reaction at 70℃ for 15min;

[0109] (2) Add 15g of crosslinking agent (divinylbenzene) and 8g of emulsifier (span80) to the prepolymer obtained in the above steps to obtain an organic phase;

[0110] (3) Prepare 300g of calcium chloride aqueous solution with a concentration of 18g / L, add it to the above organic phase at a rate of 700rpm, stir, and obtain polymer emulsion;

[0111] (4) The polymer emulsion from the previous step is heated at 60°C for 105 hours and then dried to obtain a porous microwave absorbing material.

[0112] Comparative Example 4

[0113] (1) Add 70g of polymer monomer (styrene), 1.3g of initiator (azobisisobutyronitrile), and 20g of nano-conductive filler (carbon black) to the reactor and carry out a prepolymerization reaction at 70℃ for 15min;

[0114] (2) Add 15g of crosslinking agent (divinylbenzene) and 8g of emulsifier (span80) to the prepolymer obtained in the above steps to obtain an organic phase;

[0115] (3) Prepare 300g of calcium chloride aqueous solution with a concentration of 18g / L, add it to the above organic phase at a rate of 700rpm, and stir for 5-10 minutes to obtain a polymer emulsion;

[0116] (4) The polymer emulsion from the previous step is heated at 60°C for 105 hours and then dried to obtain a porous microwave absorbing material.

[0117] Comparative Example 5

[0118] (1) Add 70g of polymer monomer (styrene), 1.3g of initiator (azobisisobutyronitrile), and 8g of nano-conductive filler (carbon black) to the reactor and carry out a prepolymerization reaction at 70℃ for 15min;

[0119] (2) Add 15g of crosslinking agent (divinylbenzene) and 8g of emulsifier (span80) to the prepolymer obtained in the above steps to obtain an organic phase;

[0120] (3) Prepare 920g of calcium chloride aqueous solution with a concentration of 18g / L, add it to the above organic phase at a rate of 700rpm, and stir for 5-10 minutes to obtain a polymer emulsion;

[0121] (4) The polymer emulsion from the previous step is heated at 60°C for 105 hours and then dried to obtain a porous microwave absorbing material.

[0122] The specific composition and reaction conditions of each of the above embodiments and comparative examples are summarized in Table 1.

[0123] Table 1. Components and reaction conditions of the examples and comparative examples

[0124]

[0125] Experimental Example 1

[0126] The porous absorbing materials obtained in the above embodiments and comparative examples were tested for mechanical and microwave absorption properties. The results are shown in Table 2.

[0127] The apparent density was determined according to GB / T 6343-2009 Determination of Apparent Density of Foamed Plastics and Rubber; the tensile strength was determined according to ASTM-D638-2010 Tensile Strength of Plastics; the compressive strength was determined according to GB / T8813-2008 Determination of Compression Properties of Rigid Foamed Plastics; the porosity was determined according to GB / T10799-2008 Determination of Open and Closed Cell Volume Percentage of Rigid Foamed Plastics; and the absorption bandwidth and absorptivity were determined according to GJB 2038A-2011 Test Method for Reflectivity of Radar Absorbing Materials.

[0128] Table 2. Test results of material mechanical and microwave absorption properties

[0129]

[0130] The experimental results show that the absorbing agent plays a crucial role in the absorbing material, and its content has a complex relationship with the absorbing performance. When the amount of absorbing agent decreases, the overall absorbing performance shows a downward trend. This is because the absorbing agent is a key component for electromagnetic wave absorption, and its reduction directly leads to a decrease in the effective material that can interact with electromagnetic waves and convert energy (Comparative Example 3). However, when an excessive amount of absorbing agent is added, the absorbing performance also decreases, mainly due to inappropriate impedance matching (Comparative Example 4). This causes a significant change in the electromagnetic parameters of the material, making it difficult to match the impedance of free space. This results in strong reflection of electromagnetic waves at the material interface, preventing them from effectively penetrating the material and being absorbed by the absorbing agent.

[0131] The prepolymerization reaction of the microwave absorber also plays an important role in its microwave absorption and mechanical properties. In the unpolymerized material (Comparative Example 2), the microwave absorber cannot be uniformly distributed within the polymer, leading to a decrease in microwave absorption and mechanical properties. Furthermore, suitable prepolymerization conditions also affect performance. When the prepolymerization temperature is too high or the time is too long (Comparative Example 1), the polymer viscosity increases, making it difficult to disperse well in the aqueous phase. This results in a poor polymer cell structure, significant adhesion, and uneven distribution of the microwave absorber throughout the polymer, leading to inconsistent mechanical and microwave absorption properties.

[0132] Furthermore, the ratio of oil phase to water phase also affects the porosity of the polymer. When the oil-water ratio is excessively reduced, the porosity increases, leading to a decrease in the mechanical properties of the porous material (Comparative Example 5).

[0133] The above description is merely a preferred embodiment of this application and is not intended to limit the application in any other way. Any person skilled in the art may make changes or modifications to the disclosed technical content to create equivalent embodiments. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of this application without departing from the scope of the technical solution of this application shall still fall within the protection scope of this application.

Claims

1. A method for preparing a porous microwave absorbing material, comprising: The monomer material, initiator, and nano-conductive filler are mixed and subjected to a prepolymerization reaction. Adding a crosslinking agent and an emulsifier to the mixture after the prepolymerization reaction yields an organic phase. Prepare an aqueous phase by adding it to the organic phase and stirring to obtain a polymer emulsion. The porous microwave absorbing material is obtained by polymerizing the polymer emulsion.

2. The preparation method according to claim 1, wherein, The polymer monomer is one or more of styrene, methyl methacrylate, methyl acrylate, and ethyl acrylate, and / or the initiator is selected from azo initiators or peroxide initiators, preferably azobisisobutyronitrile, azobisisoheptanenitrile, benzoyl peroxide, di-tert-butyl peroxide, or cumene hydroperoxide, and / or the nano-conductive filler is selected from one or more of carbon black, carbon nanotubes, carbon fibers, metal nanomaterials, and metal nanowires, preferably carbon black or carbon nanotubes.

3. The preparation method according to claim 1, wherein, The mass ratio of the polymerizable monomer material, initiator, and nano-conductive filler in the prepolymerization reaction is 50-80:0.1-5:5-15.

4. The preparation method according to claim 1, wherein, The temperature of the prepolymerization reaction is 50-80℃, and the prepolymerization time is 10-20 min.

5. The preparation method according to claim 1, wherein, The crosslinking agent is selected from one or more of ethylene glycol dimethacrylate, divinylbenzene, triallyl cyanurate and pentaerythritol triacrylate, preferably divinylbenzene, and / or the emulsifier is selected from one or more of span20, span80, DDBSS, CATB and Hypermer 1070, preferably span80.

6. The preparation method according to claim 1, wherein, By mass percentage, the organic phase comprises 50-80% polymeric monomer material, 0.1-5% initiator, 5-15% nano-conductive filler, 10-25% crosslinking agent, and 5-15% emulsifier.

7. The preparation method according to claim 1, wherein, The aqueous phase is a calcium chloride aqueous solution, preferably with a concentration of 5-25 g / L.

8. The preparation method according to claim 1, wherein, The stirring rate is 300-1000 rpm.

9. The preparation method according to claim 1, wherein, The polymerization temperature is 50-80℃, and the polymerization reaction time is 24-120h.

10. The preparation method according to claim 1, wherein, The weight ratio of the organic phase to the aqueous phase in the polymer emulsion is 15-30:70-85.

11. The porous absorbing material prepared by the preparation method according to any one of claims 1-10.

12. The porous absorbing material according to claim 11, wherein, The density of the porous absorbing material is 200-300 kg / m³. 3 The porosity is 70%-85%.

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