Porous material as well as preparation method and application thereof

Abstract

The invention provides a porous material as well as a preparation method and application thereof, and belongs to the technical field of filtering materials. The preparation method provided by the invention comprises the following steps: mixing a monomer, a cross-linking agent, an emulsifier and a co-emulsifier to obtain a continuous phase; the monomer comprises a styrene monomer and an acrylate monomer; mixing an initiator, a stabilizer and water to obtain a dispersed phase; mixing the continuous phase and the dispersed phase to obtain a pre-emulsified emulsion; shearing the pre-emulsified emulsion to obtain a high internal phase emulsion; and carrying out polymerization reaction on the high internal phase emulsion to obtain the porous material. By controlling the mass fraction of the emulsifier in the continuous phase and the volume fraction of the dispersed phase in the pre-emulsified emulsion, the size of the dispersed phase liquid drops in the high internal phase emulsion is controlled, so that the porosity and the pore diameter of the porous material are adjustable, and the prepared porous material can be used as a centrifugal tube core and can be used as a centrifugal tube. Two technologies of centrifugal separation and size screening are integrated by utilizing an internal pore structure, so that more accurate and more efficient separation is realized.

Description

Technical Field

[0001] This invention belongs to the field of filtration materials technology, specifically relating to a porous material, its preparation method, and its application. Background Technology

[0002] As a core process in modern industrial production and scientific research, filtration and separation technology plays an irreplaceable role in environmental protection, biomedicine, and food processing. With the increasing severity of global water scarcity and environmental pollution, the application of high-efficiency separation technology in water treatment has become even more valuable, effectively removing microplastics, heavy metal ions, and organic pollutants from water, ensuring drinking water safety. In the biomedical field, precision filtration technology is a key means of achieving cell separation, protein purification, and drug preparation, directly affecting the quality and therapeutic effects of medical products. In the food industry, membrane separation technology is widely used in processes such as beverage clarification and dairy product sterilization, maximizing the retention of nutrients while ensuring food safety.

[0003] Currently, traditional filtration technologies face common problems such as insufficient separation precision, low processing efficiency, and high energy consumption. Especially when dealing with challenging tasks such as separating nanoscale pollutants and handling high-viscosity fluids, conventional filter materials often exhibit defects such as poor selectivity, easy clogging, and short service life. Developing novel filter materials with controllable pore size distribution, excellent mechanical properties, and long-term stability has become a crucial breakthrough in solving current separation technology challenges. To address these separation problems, existing technologies have developed filter-type centrifuge tubes with filter membranes mounted at the bottom or sidewalls. These devices achieve sieving by forcing liquids through the filter membrane under centrifugal force. However, this structure has some drawbacks: its filtration function relies solely on a two-dimensional planar filter membrane, resulting in a small effective filtration area, low filtration flux, and easy clogging; such filter membranes typically require an additional porous support plate for fixation, making the structure relatively complex; the filter membranes are mostly for single use, difficult to regenerate after clogging, and have relatively high operating costs.

[0004] In fields such as biomedicine, environmental engineering, and chemical separation, the demand for high-efficiency, high-selectivity filtration materials is growing. Although traditional centrifuge tubes are widely used, they still have some limitations. Traditional centrifuge tubes separate particles by sedimentation, relying on differences in particle density and mass, which cause particles to settle to the bottom of the tube under centrifugal force, thus limiting the separation range. Summary of the Invention

[0005] The purpose of this invention is to provide a porous material, its preparation method, and its applications. The porous material prepared by the method provided by this invention has adjustable pore size, high open area and porosity, and can separate components of different particle sizes when used as a centrifuge core, exhibiting excellent filtration performance.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a method for preparing porous materials, comprising the following steps: (1) The monomer, crosslinking agent, emulsifier and co-emulsifier are mixed to obtain a continuous phase; the monomer includes styrene monomers and acrylate monomers; the mass fraction of the emulsifier in the continuous phase is 8~28%; (2) Mix the initiator, stabilizer and water to obtain the dispersed phase; (3) The continuous phase obtained in step (1) and the dispersed phase obtained in step (2) are mixed to obtain a pre-emulsified emulsion; the volume fraction of the dispersed phase in the pre-emulsified emulsion is 75-90%; (4) The pre-emulsified emulsion obtained in step (3) is sheared to obtain a high internal phase emulsion; the high internal phase emulsion is polymerized to obtain a porous material; The steps (1) and (2) are not in any particular order.

[0007] Preferably, the styrene monomer in step (1) includes styrene and / or methylstyrene; the acrylate monomer includes one or more of butyl acrylate, ethyl acrylate and isooctyl acrylate; the mass ratio of the styrene monomer to the acrylate monomer is (1~4):1.

[0008] Preferably, the crosslinking agent in step (1) includes alcohol ester organic compounds and / or amide organic compounds; the mass ratio of the crosslinking agent to the monomer is (4~17):100.

[0009] Preferably, the emulsifier in step (1) includes one or more of Span 80, Span 20 and polyglycerol-3-diisostearate.

[0010] Preferably, the co-emulsifier in step (1) includes one or more of dimethyl dioctadecyl ammonium chloride, di-long-chain alkyl ester quaternary ammonium salt, dihydrogenated tartrate dimethyl ammonium chloride, and polyglycerol-3 polyricinoleate; the mass ratio of the co-emulsifier to the monomer is (0.5~1):100.

[0011] Preferably, the initiator in step (2) is persulfate; the mass ratio of the initiator in step (2) to the monomer in step (1) is (1~5):100.

[0012] Preferably, the stabilizer in step (2) includes sodium chloride and / or calcium chloride; the mass ratio of the stabilizer in step (2) to the monomer in step (1) is (1.5~3):100.

[0013] Preferably, the polymerization temperature in step (4) is 70~85℃ and the polymerization time is 8~24h.

[0014] The present invention also provides porous materials prepared by the preparation method described in the above technical solution.

[0015] The present invention also provides the application of the porous material described in the above technical solution as a centrifuge core.

[0016] This invention provides a method for preparing a porous material, comprising the following steps: (1) mixing monomers, crosslinking agents, emulsifiers and co-emulsifiers to obtain a continuous phase; the monomers include styrene monomers and acrylate monomers; the mass fraction of the emulsifier in the continuous phase is 8-28%; (2) mixing an initiator, a stabilizer and water to obtain a dispersed phase; (3) mixing the continuous phase obtained in step (1) and the dispersed phase obtained in step (2) to obtain a pre-emulsified emulsion; the volume fraction of the dispersed phase in the pre-emulsified emulsion is 75-90%; (4) shearing the pre-emulsified emulsion obtained in step (3) to obtain a high internal phase emulsion; and polymerizing the high internal phase emulsion to obtain a porous material; steps (1) and (2) are not in any particular order. This invention controls the size of the dispersed phase droplets in the high internal phase emulsion by controlling the mass fraction of the emulsifier in the continuous phase and the volume fraction of the dispersed phase in the pre-emulsified emulsion. This allows the porosity and pore size of the porous material to be adjusted. The prepared porous material can be used as a centrifuge core. By utilizing the internal pore structure, centrifugation and size sieving technologies are integrated to achieve more precise and efficient separation. Components of a specific size can be separated quickly and efficiently from the sample that needs to be separated. Attached Figure Description

[0017] Figure 1 Images of the porous material prepared in Example 1 of this invention; Figure 2 SEM image of the porous material prepared in Example 1 of this invention; Figure 3 SEM image of the porous material prepared in Example 2 of this invention; Figure 4 SEM image of the porous material prepared in Example 3 of this invention; Figure 5 SEM image of the porous material prepared in Example 4 of this invention; Figure 6 This is a SEM image of the porous material prepared in Example 5 of the present invention; Figure 7 SEM image of the porous material prepared in Example 6 of this invention; Figure 8 An image of the porous material prepared in Comparative Example 1; Figure 9 The image shows a SEM image of the porous material prepared in Comparative Example 2. Detailed Implementation

[0018] This invention provides a method for preparing porous materials, comprising the following steps: (1) Mix monomers, crosslinking agents, emulsifiers and co-emulsifiers to obtain a continuous phase; (2) Mix the initiator, stabilizer and water to obtain the dispersed phase; (3) Mix the continuous phase obtained in step (1) and the dispersed phase obtained in step (2) to obtain a pre-emulsified emulsion; (4) The pre-emulsified emulsion obtained in step (3) is sheared to obtain a high internal phase emulsion; the high internal phase emulsion is polymerized to obtain a porous material; The steps (1) and (2) are not in any particular order.

[0019] Unless otherwise specified, the present invention does not impose any special restrictions on the source of the raw materials, and commercially available products well known to those skilled in the art can be used.

[0020] This invention mixes monomers, crosslinking agents, emulsifiers, and co-emulsifiers to obtain a continuous phase.

[0021] In this invention, the monomers include styrene monomers and acrylate monomers.

[0022] In this invention, the styrene monomers preferably include styrene and / or methylstyrene; the acrylate monomers preferably include one or more of butyl acrylate, ethyl acrylate and isooctyl acrylate.

[0023] In this invention, the preferred mass ratio of the styrene monomer to the acrylate monomer is (1~4):1. As one embodiment, the mass ratio of the styrene monomer to the acrylate monomer can specifically be 1:1, 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1, or 4:1.

[0024] By using the two monomers mentioned above and controlling their mass ratio, the present invention can produce porous materials with excellent mechanical strength, which are suitable for high-speed centrifugation.

[0025] In this invention, the crosslinking agent preferably comprises an alcohol ester organic compound and / or an amide organic compound. As one embodiment, the alcohol ester organic compound may be ethylene glycol dimethacrylate; the amide organic compound may be diacetone acrylamide, N-hydroxymethylacrylamide, or N,N'-methylenebisacrylamide.

[0026] In this invention, the preferred mass ratio of the crosslinking agent to the monomer is (4~17):100. As one embodiment, the mass ratio of the crosslinking agent to the monomer can specifically be 4:100, 5:100, 6:100, 7:100, 8:100, 9:100, 10:100, 11:100, 12:100, 13:100, 14:100, 15:100, 16:100, or 17:100.

[0027] This invention controls the type and amount of crosslinking agent, which can further improve the mechanical strength and pore structure regularity of porous materials, thereby further improving their filtration performance.

[0028] In this invention, the emulsifier preferably includes one or more of Span 80, Span 20, and polyglycerol-3-diisostearate.

[0029] In this invention, the mass fraction of the emulsifier in the continuous phase is 8-28%. As one embodiment, the mass fraction of the emulsifier in the continuous phase can specifically be 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, or 28%.

[0030] The higher the mass fraction of the emulsifier, the higher the open-cell ratio and porosity of the resulting porous material, but the smaller the pore size. When the mass fraction of the emulsifier is less than 8%, the open-cell ratio of the porous material is relatively low. This invention controls the type and amount of emulsifier, which can control the droplet size of the dispersed phase in the high internal phase emulsion, thereby adjusting the porosity and pore size of the porous material and improving the open-cell ratio, thus improving the filtration effect of the porous material.

[0031] In this invention, the co-emulsifier preferably includes one or more of dimethyl dioctadecyl ammonium chloride, di-long-chain alkyl ester quaternary ammonium salt, dihydrogenated tartrate dimethyl ammonium chloride, and polyglycerol-3 polyricinoleate.

[0032] In this invention, the preferred mass ratio of the co-emulsifier to the monomer is (0.5~1):100. As one embodiment, the mass ratio of the co-emulsifier to the monomer can be specifically 0.5:100, 0.6:100, 0.7:100, 0.8:100, 0.9:100, or 1:100.

[0033] This invention controls the type and amount of co-emulsifier, which can improve emulsification efficiency, further increase the porosity of porous materials, and adjust the material pore size to meet the requirements for separating target particles, thereby further improving the filtration performance of porous materials.

[0034] In one embodiment, the monomer, crosslinking agent, emulsifier, and co-emulsifier are mixed under stirring conditions; the stirring rate can be 200 rpm. This invention does not have a specific limitation on the stirring time, as long as the raw materials are mixed evenly.

[0035] The present invention mixes an initiator, a stabilizer and water to obtain a dispersed phase.

[0036] In this invention, the initiator is preferably a persulfate. As one embodiment, the persulfate may be potassium persulfate.

[0037] In this invention, the preferred mass ratio of the initiator to the monomer is (1~5):100. As one embodiment, the mass ratio of the initiator to the monomer can specifically be 1:100, 1.5:100, 2:100, 2.5:100, 3:100, 3.5:100, 4:100, 4.5:100, or 5:100.

[0038] This invention controls the type and amount of initiator, enabling the polymerization reaction to proceed smoothly, further increasing the porosity of porous materials, reducing pore size, and further improving the filtration performance of porous materials.

[0039] In this invention, the stabilizer preferably includes sodium chloride and / or calcium chloride.

[0040] In this invention, the preferred mass ratio of the stabilizer to the monomer is (1.5~3):100. As one embodiment, the mass ratio of the stabilizer to the monomer can specifically be 1.5:100, 2:100, 2.5:100, or 3:100.

[0041] This invention controls the type and amount of stabilizer, which can further improve the stability of high internal phase emulsion, thereby improving the mechanical properties of the polymerized porous material, the uniformity of the pore size of the porous material, and other properties, thereby further improving the filtration performance of the porous material.

[0042] In one implementation method, the water is deionized water.

[0043] The present invention does not have a special limitation on the amount of water used, as long as the volume fraction of the dispersed phase in the high internal phase emulsion is within the required range.

[0044] In one embodiment, the initiator, stabilizer, and water are mixed under ultrasonic conditions. The present invention does not impose specific limitations on the power and duration of the ultrasound, as long as the initiator and stabilizer are fully dissolved in the water.

[0045] After obtaining the continuous phase and the dispersed phase, the present invention mixes the continuous phase and the dispersed phase to obtain a pre-emulsified emulsion.

[0046] In this invention, the dispersed phase is preferably added dropwise to the continuous phase under stirring conditions. After the addition is completed, the mixture is stirred for 4 to 6 minutes to obtain a pre-emulsified emulsion.

[0047] In this invention, the stirring rate is preferably 150~450 rpm, more preferably 180~350 rpm, and even more preferably 200~250 rpm.

[0048] In this invention, the dropping rate of the dispersed phase is preferably 1~6 mL / min, more preferably 2~5 mL / min, and even more preferably 3 mL / min.

[0049] In this invention, the dripping is preferably carried out at room temperature.

[0050] In this invention, the volume fraction of the dispersed phase in the pre-emulsified emulsion is 75-90%. As one embodiment, the volume fraction of the dispersed phase in the pre-emulsified emulsion can specifically be 75%, 80%, 85%, or 90%. This invention controls the volume fraction of the dispersed phase in the pre-emulsified emulsion. When its volume dispersion is below 75%, it is not considered a high internal phase emulsion. When its volume dispersion is too high, it leads to excessively high viscosity in the high internal phase emulsion, resulting in large air bubbles during polymerization. This causes large air bubbles to appear inside the porous material, affecting its performance. Controlling the volume fraction of the dispersed phase in the pre-emulsified emulsion in this invention can improve the use and separation effect of porous materials.

[0051] After obtaining the pre-emulsified emulsion, the present invention shears the pre-emulsified emulsion to obtain a high internal phase emulsion; and then polymerizes the high internal phase emulsion to obtain a porous material.

[0052] In this invention, the shearing rate is preferably 9-18 krpm, more preferably 10-15 krpm, and even more preferably 12-13 krpm; the shearing time is preferably 1-5 min. By performing shearing and controlling the shearing rate and time, this invention enables the porous material to have uniform pore size and better connectivity.

[0053] In this invention, the preferred temperature for the polymerization reaction is 70-85°C; the preferred time for the polymerization reaction is 8-24 hours. As one embodiment, the specific temperature for the polymerization reaction can be 70°C, 71°C, 72°C, 73°C, 74°C, 75°C, 76°C, 77°C, 78°C, 79°C, 80°C, 81°C, 82°C, 83°C, 84°C, or 85°C; the specific time for the polymerization reaction can be 8 hours, 10 hours, 12 hours, 15 hours, 18 hours, 20 hours, 22 hours, or 24 hours. By controlling the temperature and time of the polymerization reaction within the above ranges, this invention allows the polymerization reaction to proceed fully and achieves a suitable polymerization rate, resulting in a more uniform pore size in the porous material.

[0054] In one embodiment, the polymerization reaction is carried out in a mold; the mold is made of polytetrafluoroethylene.

[0055] In one implementation, the size and shape of the mold are such that porous materials can be selected as centrifuge cores.

[0056] After the polymerization reaction is completed, the products of the polymerization reaction are preferably washed and dried sequentially.

[0057] In this invention, the washing solution used is preferably ethanol; the volume of the ethanol is preferably 3 to 5 times the volume of the solid product after the polymerization reaction; and the washing time is preferably 24 hours. This invention uses washing to remove unreacted monomers, emulsifiers, and other raw materials.

[0058] In this invention, the drying process preferably includes atmospheric pressure drying, vacuum drying, or freeze drying.

[0059] In this invention, the temperature of atmospheric pressure drying is preferably 25~40℃; the time of atmospheric pressure drying is preferably 24~72h; the temperature of vacuum drying is preferably 30~55℃; the pressure of vacuum drying is preferably -90~-20kPa; the time of vacuum drying is preferably 24~48h; the temperature of freeze drying is preferably -90~-60℃; the time of freeze drying is preferably 24~48h.

[0060] The preparation method provided by this invention controls the size of the dispersed phase droplets in the high internal phase emulsion by controlling parameters such as the ratio of the dispersed phase to the continuous phase, the mass fraction of the emulsifier in the continuous phase, and the shear rate, thereby increasing the porosity and changing the pore size of the porous material. The pore size of the porous material is adjustable, and it has high porosity and open porosity. When used as a centrifuge core, it differs from traditional centrifuge tubes that utilize velocity sedimentation. The porous material centrifuge core can integrate centrifugal separation and size sieving technologies through its internal pore structure, achieving more precise and efficient separation. At the same time, the use of two monomers and the control of their mass ratio give the porous material better mechanical strength, making it more suitable for centrifugal separation. In addition, the preparation method of this invention is simple and easy to operate.

[0061] The present invention also provides porous materials prepared by the preparation method described in the above technical solution.

[0062] The porous materials prepared by this invention have a very high porosity (100%), a porosity of 80-92%, and a density of 0.07-0.21 g / cm³. 3 .

[0063] The present invention also provides the application of the porous material described in the above technical solution as a centrifuge core.

[0064] The porous material provided by this invention has high mechanical strength, high open area ratio and high porosity, and can be used as a centrifuge core.

[0065] This invention places porous materials in centrifuge tubes, then adds the sample to be separated, and performs centrifugation.

[0066] The porous material provided by this invention can be used as a centrifuge core in studies such as cell biology, molecular biology, and component separation. In these studies, it is often necessary to rapidly and efficiently separate components of specific sizes from mixed samples, such as separating circulating tumor cells from whole blood or separating cell nuclei and cell walls from lysates. The porous material prepared by this invention has an adjustable pore size, allowing for the preparation of porous materials with different pore sizes according to the particle size of the components to be separated. When used as a centrifuge core, it enables faster and more efficient separation of components of the desired size.

[0067] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0068] Example 1 A method for preparing a porous material is as follows: (1) At room temperature, 7.2g of monomer (5.4g of styrene, 1.8g of butyl acrylate), 1.2g of crosslinking agent (ethylene glycol dimethacrylate), 1.2g of emulsifier (Span 80) and 0.06g of co-emulsifier (dimethyl dioctadecyl ammonium chloride) are stirred and mixed evenly at 200rpm to obtain a continuous phase, wherein the mass ratio of styrene to butyl acrylate is 3:1, the mass ratio of crosslinking agent to monomer is 16.7:100, the mass fraction of emulsifier in the continuous phase is 12.4%, and the mass ratio of co-emulsifier to monomer is 0.83:100; (2) At room temperature, 0.18 g of initiator (potassium persulfate) and 0.15 g of stabilizer (sodium chloride) were added to 54 g of deionized water and dissolved by ultrasonication to obtain a dispersed phase, wherein the mass ratio of initiator to monomer was 2.5:100 and the mass ratio of stabilizer to monomer was 2.1:100; (3) Under the conditions of room temperature and stirring at 200 rpm, the dispersed phase was added dropwise to the continuous phase at a rate of 3 mL / min. After the addition was completed, the mixture was stirred at 250 rpm for 5 min to obtain a pre-emulsified emulsion. The volume fraction of the dispersed phase in the pre-emulsified emulsion was 85%. (4) The pre-emulsified emulsion obtained in step (3) is sheared at a rate of 12krpm for 2min to obtain a high internal phase emulsion. The high internal phase emulsion is poured into a mold and sealed. The polymerization reaction is carried out at 70℃ water bath for 24h. After the polymerization reaction is completed, it is washed with 4 times the volume of solid ethanol for 24h. Then it is vacuum dried at 50℃ and -50kPa for 48h to obtain a porous material.

[0069] Images of the porous material prepared in Example 1 are shown below. Figure 1 As shown.

[0070] The morphology of the porous material prepared in Example 1 was observed using a scanning electron microscope (SEM, S-3400, JEOL), and the results are as follows. Figure 2 As shown. From Figure 2 As can be seen, the pore size of the porous material is 2.73 μm.

[0071] The compressive strength of the porous material prepared in Example 1 was measured to be 0.86 MPa and the compressive modulus was 25.53 MPa using a universal testing machine (LD23.104), which meets the strength requirements under high-speed centrifugation.

[0072] The porous material prepared in Example 1 was placed in a commercially available 15 mL plastic centrifuge tube to separate 300 nm and 3 μm microspheres. The retention rate data are shown in Table 1.

[0073] Table 1 shows the retention rates of the porous material prepared in Example 1 for 300 nm and 3 μm microspheres when placed in ordinary commercially available 15 mL plastic centrifuge tubes.

[0074] Example 2 A method for preparing a porous material is as follows: (1) At room temperature, 7.2g of monomer (5.4g of styrene, 1.8g of butyl acrylate), 1.2g of crosslinking agent (ethylene glycol dimethacrylate), 1.2g of emulsifier (Span 80) and 0.06g of co-emulsifier (dimethyl dioctadecyl ammonium chloride) are stirred and mixed evenly at 200rpm to obtain a continuous phase, wherein the mass ratio of styrene to butyl acrylate is 3:1, the mass ratio of crosslinking agent to monomer is 16.7:100, the mass fraction of emulsifier in the continuous phase is 12.4%, and the mass ratio of co-emulsifier to monomer is 0.83:100; (2) At room temperature, 0.18 g of initiator (potassium persulfate) and 0.15 g of stabilizer (sodium chloride) were added to deionized water and dissolved by ultrasonication to obtain a dispersed phase, wherein the mass ratio of initiator to monomer was 2.5:100 and the mass ratio of stabilizer to monomer was 2.1:100; (3) Under the conditions of room temperature and stirring at 200 rpm, the dispersed phase was added dropwise to the continuous phase at a rate of 3 mL / min. After the addition was completed, the mixture was stirred at 250 rpm for 5 min to obtain a pre-emulsified emulsion. The volume fraction of the dispersed phase in the pre-emulsified emulsion was 75%. (4) The pre-emulsified emulsion obtained in step (3) is sheared at a rate of 12krpm for 2min to obtain a high internal phase emulsion. The high internal phase emulsion is poured into a mold and sealed. The polymerization reaction is carried out at 70℃ water bath for 24h. After the polymerization reaction is completed, it is washed with 4 times the volume of solid ethanol for 24h. Then it is vacuum dried at 50℃ and -50kPa for 48h to obtain a porous material.

[0075] The morphology of the porous material prepared in Example 2 was observed using a scanning electron microscope (SEM, S-3400, JEOL), and the results are as follows. Figure 3 As shown. From Figure 3 As can be seen, the pore size of the porous material is 1.27 μm.

[0076] The compressive strength of the porous material prepared in Example 2 was measured to be 2.08 MPa and the compressive modulus was 53.42 MPa using a universal testing machine (LD23.104), which meets the strength requirements under high-speed centrifugation.

[0077] The porous material prepared in Example 2 was placed in a commercially available 15 mL plastic centrifuge tube to separate 300 nm and 3 μm microspheres. The retention rate data are shown in Table 2.

[0078] Table 2 shows the retention rates of the porous material prepared in Example 2 for 300 nm and 3 μm microspheres when placed in ordinary commercially available 15 mL plastic centrifuge tubes.

[0079] Example 3 A method for preparing a porous material is as follows: (1) At room temperature, 7.2g of monomer (5.4g of styrene, 1.8g of butyl acrylate), 1.2g of crosslinking agent (ethylene glycol dimethacrylate), 1.2g of emulsifier (Span 80) and 0.06g of co-emulsifier (dimethyl dioctadecyl ammonium chloride) are stirred and mixed evenly at 200rpm to obtain a continuous phase, wherein the mass ratio of styrene to butyl acrylate is 3:1, the mass ratio of crosslinking agent to monomer is 16.7:100, the mass fraction of emulsifier in the continuous phase is 12.4%, and the mass ratio of co-emulsifier to monomer is 0.83:100; (2) At room temperature, 0.18 g of initiator (potassium persulfate) and 0.15 g of stabilizer (sodium chloride) were added to deionized water and dissolved by ultrasonication to obtain a dispersed phase, wherein the mass ratio of initiator to monomer was 2.5:100 and the mass ratio of stabilizer to monomer was 2.1:100; (3) Under the conditions of room temperature and stirring at 200 rpm, the dispersed phase was added dropwise to the continuous phase at a rate of 3 mL / min. After the addition was completed, the mixture was stirred at 250 rpm for 5 min to obtain a pre-emulsified emulsion. The volume fraction of the dispersed phase in the pre-emulsified emulsion was 80%. (4) The pre-emulsified emulsion obtained in step (3) is sheared at a rate of 12krpm for 2min to obtain a high internal phase emulsion. The high internal phase emulsion is poured into a mold and sealed. The polymerization reaction is carried out at 70℃ water bath for 24h. After the polymerization reaction is completed, it is washed with 4 times the volume of solid ethanol for 24h. Then it is vacuum dried at 50℃ and -50kPa for 48h to obtain a porous material.

[0080] The morphology of the porous material prepared in Example 3 was observed using a scanning electron microscope (SEM, S-3400, JEOL), and the results are as follows. Figure 4 As shown. From Figure 4 As can be seen, the pore size of the porous material is 1.65 μm.

[0081] The compressive strength of the porous material prepared in Example 3 was measured to be 1.04 MPa and the compressive modulus was 40.28 MPa using a universal testing machine (LD23.104), which meets the strength requirements under high-speed centrifugation.

[0082] The porous material prepared in Example 3 was placed in a commercially available 15mL plastic centrifuge tube to separate 300nm and 3μm microspheres. The retention rate data are shown in Table 3.

[0083] Table 3 shows the retention rates of the porous material prepared in Example 3 for 300 nm and 3 μm microspheres when placed in ordinary commercially available 15 mL plastic centrifuge tubes.

[0084] Example 4 A method for preparing a porous material is as follows: (1) At room temperature, 7.2g of monomer (5.4g of styrene, 1.8g of butyl acrylate), 1.2g of crosslinking agent (ethylene glycol dimethacrylate), 1.2g of emulsifier (Span 80) and 0.06g of co-emulsifier (dimethyl dioctadecyl ammonium chloride) are stirred and mixed evenly at 200rpm to obtain a continuous phase, wherein the mass ratio of styrene to butyl acrylate is 3:1, the mass ratio of crosslinking agent to monomer is 16.7:100, the mass fraction of emulsifier in the continuous phase is 12.4%, and the mass ratio of co-emulsifier to monomer is 0.83:100; (2) At room temperature, 0.18 g of initiator (potassium persulfate) and 0.15 g of stabilizer (sodium chloride) were added to deionized water and dissolved by ultrasonication to obtain a dispersed phase, wherein the mass ratio of initiator to monomer was 2.5:100 and the mass ratio of stabilizer to monomer was 2.1:100; (3) Under the conditions of room temperature and stirring at 200 rpm, the dispersed phase was added dropwise to the continuous phase at a rate of 3 mL / min. After the addition was completed, the mixture was stirred at 250 rpm for 5 min to obtain a pre-emulsified emulsion. The volume fraction of the dispersed phase in the pre-emulsified emulsion was 90%. (4) The pre-emulsified emulsion obtained in step (3) is sheared at a rate of 12krpm for 2min to obtain a high internal phase emulsion. The high internal phase emulsion is poured into a mold and sealed. The polymerization reaction is carried out at 70℃ water bath for 24h. After the polymerization reaction is completed, it is washed with 4 times the volume of solid ethanol for 24h. Then it is vacuum dried at 50℃ and -50kPa for 48h to obtain a porous material.

[0085] The morphology of the porous material prepared in Example 4 was observed using a scanning electron microscope (SEM, S-3400, JEOL), and the results are as follows. Figure 5 As shown. From Figure 5 As can be seen, the pore size of the porous material is 2.94 μm.

[0086] The compressive strength of the porous material prepared in Example 4 was measured to be 0.37 MPa and the compressive modulus was 15.42 MPa using a universal testing machine (LD23.104), which meets the strength requirements under high-speed centrifugation.

[0087] The porous material prepared in Example 4 was placed in a commercially available 15 mL plastic centrifuge tube to separate 300 nm and 3 μm microspheres. The retention rate data are shown in Table 4.

[0088] Table 4 shows the retention rates of the porous material prepared in Example 4 for 300 nm and 3 μm microspheres when placed in ordinary commercially available 15 mL plastic centrifuge tubes.

[0089] Example 5 A method for preparing a porous material is as follows: (1) At room temperature, 7.2g of monomer (5.4g of styrene, 1.8g of butyl acrylate), 1.2g of crosslinking agent (ethylene glycol dimethacrylate), 0.74g of emulsifier (Span 80) and 0.06g of co-emulsifier (dimethyl dioctadecyl ammonium chloride) are stirred and mixed evenly at 200rpm to obtain a continuous phase, wherein the mass ratio of styrene to butyl acrylate is 3:1, the mass ratio of crosslinking agent to monomer is 16.7:100, the mass fraction of emulsifier in the continuous phase is 8%, and the mass ratio of co-emulsifier to monomer is 0.83:100; (2) At room temperature, 0.18 g of initiator (potassium persulfate) and 0.15 g of stabilizer (sodium chloride) were added to deionized water and dissolved by ultrasonication to obtain a dispersed phase, wherein the mass ratio of initiator to monomer was 2.5:100 and the mass ratio of stabilizer to monomer was 2.1:100; (3) Under the conditions of room temperature and stirring at 200 rpm, the dispersed phase was added dropwise to the continuous phase at a rate of 3 mL / min. After the addition was completed, the mixture was stirred at 250 rpm for 5 min to obtain a pre-emulsified emulsion. The volume fraction of the dispersed phase in the pre-emulsified emulsion was 85%. (4) The pre-emulsified emulsion obtained in step (3) is sheared at a rate of 12krpm for 2min to obtain a high internal phase emulsion. The high internal phase emulsion is poured into a mold and sealed. The polymerization reaction is carried out at 70℃ water bath for 24h. After the polymerization reaction is completed, it is washed with 4 times the volume of solid ethanol for 24h. Then it is vacuum dried at 50℃ and -50kPa for 48h to obtain a porous material.

[0090] The morphology of the porous material prepared in Example 5 was observed using a scanning electron microscope (SEM, S-3400, JEOL), and the results are as follows. Figure 6 As shown. From Figure 6 As can be seen, the pore size of the porous material is 1.42 μm.

[0091] The compressive strength of the porous material prepared in Example 5 was measured to be 0.64 MPa and the compressive modulus was 17.6 MPa using a universal testing machine (LD23.104), which meets the strength requirements under high-speed centrifugation.

[0092] The porous material prepared in Example 5 was placed in a commercially available 15mL plastic centrifuge tube to separate 300nm and 3μm microspheres. The retention rate data are shown in Table 5.

[0093] Table 5 shows the retention rates of the porous material prepared in Example 5 for 300 nm and 3 μm microspheres when placed in ordinary commercially available 15 mL plastic centrifuge tubes.

[0094] Example 6 A method for preparing a porous material is as follows: (1) At room temperature, 7.2g of monomer (5.4g of styrene, 1.8g of butyl acrylate), 1.2g of crosslinking agent (ethylene glycol dimethacrylate), 1.86g of emulsifier (Span 80) and 0.06g of co-emulsifier (dimethyl dioctadecyl ammonium chloride) are stirred and mixed evenly at 200rpm to obtain a continuous phase, wherein the mass ratio of styrene to butyl acrylate is 3:1, the mass ratio of crosslinking agent to monomer is 16.7:100, the mass fraction of emulsifier in the continuous phase is 18%, and the mass ratio of co-emulsifier to monomer is 0.83:100; (2) At room temperature, 0.18 g of initiator (potassium persulfate) and 0.15 g of stabilizer (sodium chloride) were added to deionized water and dissolved by ultrasonication to obtain a dispersed phase, wherein the mass ratio of initiator to monomer was 2.5:100 and the mass ratio of stabilizer to monomer was 2.1:100; (3) Under the conditions of room temperature and stirring at 200 rpm, the dispersed phase was added dropwise to the continuous phase at a rate of 3 mL / min. After the addition was completed, the mixture was stirred at 250 rpm for 5 min to obtain a pre-emulsified emulsion. The volume fraction of the dispersed phase in the pre-emulsified emulsion was 85%. (4) The pre-emulsified emulsion obtained in step (3) is sheared at a rate of 12krpm for 2min to obtain a high internal phase emulsion. The high internal phase emulsion is poured into a mold and sealed. The polymerization reaction is carried out at 70℃ water bath for 24h. After the polymerization reaction is completed, it is washed with 4 times the volume of solid ethanol for 24h. Then it is vacuum dried at 50℃ and -50kPa for 48h to obtain a porous material.

[0095] The morphology of the porous material prepared in Example 6 was observed using a scanning electron microscope (SEM, S-3400, JEOL), and the results are as follows. Figure 7 As shown. From Figure 7 As can be seen, the pore size of the porous material is 1.94 μm.

[0096] The compressive strength of the porous material prepared in Example 6 was measured to be 0.51 MPa and the compressive modulus was 18.14 MPa using a universal testing machine (LD23.104), which meets the strength requirements under high-speed centrifugation.

[0097] The porous material prepared in Example 6 was placed in a commercially available 15mL plastic centrifuge tube to separate 300nm and 3μm microspheres. The retention rate data are shown in Table 6.

[0098] Table 6 shows the retention rates of the porous material prepared in Example 6 for 300 nm and 3 μm microspheres when placed in ordinary commercially available 15 mL plastic centrifuge tubes.

[0099] Example 7 The amount of monomer used in step (1) of Example 1 was replaced with 4.8g of styrene and 2.4g of butyl acrylate, with a mass ratio of styrene to butyl acrylate of 2:1. All other aspects were the same as in Example 1.

[0100] The compressive strength of the porous material prepared in Example 7 was measured to be 0.41 MPa and the compressive modulus was 14.44 MPa using a universal testing machine (LD23.104), which meets the strength requirements under high-speed centrifugation.

[0101] Example 8 The amount of monomer used in step (1) of Example 1 was replaced with 5.76g of styrene and 1.44g of butyl acrylate, with a mass ratio of styrene to butyl acrylate of 4:1. All other aspects were the same as in Example 1.

[0102] The compressive strength of the porous material prepared in Example 8 was measured to be 0.59 MPa and the compressive modulus was 15.75 MPa using a universal testing machine (LD23.104), which meets the strength requirements under high-speed centrifugation.

[0103] Comparative Example 1 Steps (1) to (3) are the same as in Example 1, to obtain a pre-emulsified emulsion; (4) The pre-emulsified emulsion was not sheared and was directly poured into the mold for sealing. The polymerization reaction was carried out in a water bath at 70°C for 24 hours. After the polymerization reaction was completed, it was washed with 4 times the volume of solid ethanol for 24 hours and then vacuum dried at 50°C and -50 kPa for 48 hours to obtain the porous material.

[0104] Images of the porous materials prepared in Comparative Example 1 are shown below. Figure 8 As shown. From Figure 8 As can be seen, the lack of shear emulsification results in large and non-uniform droplet sizes. The continuous phase film between these large droplets is relatively thick, making it difficult to completely break down and form through-pores during polymerization shrinkage. At the same time, some droplets undergo local merging before polymerization, ultimately forming closed-pore structures. Comparing Example 1 and Comparative Example 1, it can be seen that shear emulsification has high energy, which can further break down droplets, making the emulsion more stable and resulting in a well-distributed pore structure after polymerization.

[0105] Comparative Example 2 5.4g styrene, 1.8g butyl acrylate, 1.2g ethylene glycol dimethacrylate and 0.18g azobisisobutyronitrile were stirred and mixed evenly, then poured into a mold and sealed. The mixture was polymerized in a water bath at 70℃ for 24h. After the polymerization reaction was completed, the mixture was washed with 4 times its volume of solid ethanol for 24h, and then vacuum dried at 50℃ and -50kPa for 48h to obtain a porous material.

[0106] The morphology of the porous material prepared in Comparative Example 2 was observed using a scanning electron microscope (SEM, S-3400, JEOL). The results are as follows: Figure 9 As shown. From Figure 9 As can be seen, porous materials have a closed-cell structure. When a porous material has a closed-cell structure, the material cannot be sieved out, and the centrifugal separation effect cannot be achieved; therefore, it cannot be used as a centrifuge core.

[0107] In summary, the preparation method provided by this invention can prepare porous materials with high porosity and different pore sizes. Furthermore, simulation separation using microspheres shows that the porous material can separate particles of different sizes and can be used as a centrifuge core to achieve separation.

[0108] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a porous material, characterized in that, Includes the following steps: (1) The monomer, crosslinking agent, emulsifier and co-emulsifier are mixed to obtain a continuous phase; the monomer includes styrene monomers and acrylate monomers; the mass fraction of the emulsifier in the continuous phase is 8~28%; (2) Mix the initiator, stabilizer and water to obtain the dispersed phase; (3) The continuous phase obtained in step (1) and the dispersed phase obtained in step (2) are mixed to obtain a pre-emulsified emulsion; the volume fraction of the dispersed phase in the pre-emulsified emulsion is 75-90%; (4) The pre-emulsified emulsion obtained in step (3) is sheared to obtain a high internal phase emulsion; the high internal phase emulsion is polymerized to obtain a porous material; The steps (1) and (2) are not in any particular order.

2. The preparation method according to claim 1, characterized in that, The styrene monomers in step (1) include styrene and / or methylstyrene; the acrylate monomers include one or more of butyl acrylate, ethyl acrylate and isooctyl acrylate; the mass ratio of the styrene monomers to the acrylate monomers is (1~4):

1.

3. The preparation method according to claim 1, characterized in that, The crosslinking agent in step (1) includes alcohol ester organic compounds and / or amide organic compounds; the mass ratio of the crosslinking agent to the monomer is (4~17):

100.

4. The preparation method according to claim 1, characterized in that, The emulsifier in step (1) includes one or more of Span 80, Span 20 and polyglycerol-3-diisostearate.

5. The preparation method according to claim 1, characterized in that, The co-emulsifier in step (1) includes one or more of dimethyl dioctadecyl ammonium chloride, di-long-chain alkyl ester quaternary ammonium salt, dihydrogenated tartrate dimethyl ammonium chloride, and polyglycerol-3 polyricinoleate; the mass ratio of the co-emulsifier to the monomer is (0.5~1):

100.

6. The preparation method according to claim 1, characterized in that, The initiator in step (2) is persulfate; the mass ratio of the initiator in step (2) to the monomer in step (1) is (1~5):

100.

7. The preparation method according to claim 1, characterized in that, The stabilizer in step (2) includes sodium chloride and / or calcium chloride; the mass ratio of the stabilizer in step (2) to the monomer in step (1) is (1.5~3):

100.

8. The preparation method according to claim 1, characterized in that, The polymerization temperature in step (4) is 70~85℃ and the polymerization time is 8~24h.

9. The porous material prepared by the preparation method according to any one of claims 1 to 8.

10. The application of the porous material of claim 9 as a centrifuge core.

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