Preparation method of porous polyurethane
By synthesizing porous polyurethanes in a one-step reaction at room temperature using multifunctional acrylates and primary amine compounds as raw materials, the problems of complex synthesis, high energy consumption and difficult recycling in existing technologies are solved, and the efficient preparation and designability of environmentally friendly porous polyurethane materials are realized.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-22
- Publication Date
- 2026-04-07
AI Technical Summary
Existing methods for synthesizing porous polyurethane materials are complex, rely on external catalysts and foaming agents, consume a lot of energy, are difficult to control the material properties, and are difficult to recycle, resulting in environmental pollution and waste of resources.
Porous polyurethane was synthesized in a one-step reaction at room temperature using multifunctional acrylates and amine compounds containing primary amine groups as raw materials and ethanol solution as solvent, avoiding the use of catalysts, foaming agents and stabilizers, and utilizing a solvent removal method.
This method enables the efficient synthesis of porous polyurethanes at room temperature, simplifies the process, reduces energy consumption, avoids catalyst residue, improves the designability and biodegradability of the material, solves the material recycling problem, and is environmentally friendly.
Smart Images
Figure CN121801077A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of high polymer material synthesis, and particularly relates to a preparation method of porous polyurethane. BACKGROUND
[0002] Traditional synthesis methods of porous polymers usually rely on physical or chemical foaming processes, which are complex and require high equipment, often need detailed optimization of formula and conditions for specific reactions, and design and screening of special catalysts, which is time-consuming and labor-intensive. In addition, most of the current porous polymers are thermosetting materials, which are difficult to recycle after disposal, and are usually treated by incineration or landfill, which not only occupies a large amount of land, but also causes serious resource waste and environmental pollution problems.
[0003] Under this background, polyurethane, as a kind of degradable synthetic polymer containing both ester bond and tertiary amine group in the main chain, shows significant material chemistry research value and application potential due to its adjustable molecular structure and diverse functionalization ability. The ester bond endows it with good degradability, while the tertiary amine group not only provides a reaction site for subsequent modification, but also can realize functional regulation through protonation. Since it was first reported in the 1970s, especially after 2000, Langer et al. successfully constructed linear polyurethane through Michael addition polymerization and applied it to gene delivery system, this kind of polymer has gradually developed into a functional polymer system different from traditional polyesters, and is widely used in drug controlled release carriers, gene transduction and biomedical imaging.
[0004] However, the current research on polyurethane is mostly focused on linear topology and dense bulk materials, and porous polyurethane materials have not been systematically developed due to limited synthesis methods. In fact, this kind of material has great potential in the field of biomedicine, such as being used as a bone / cartilage repair scaffold with through-hole structure and good biocompatibility in tissue engineering, an implantable depot system capable of achieving long-acting drug release, and a wound repair matrix with biological factor controlled release function. Therefore, from the perspective of material chemistry, developing efficient and controllable synthesis strategies for porous polyurethane not only helps to enrich the structural diversity of porous polymer systems, but also has important scientific significance for promoting the design of green functional materials and sustainable development.
[0005] Although porous polyurethane materials have good application prospects, the current research is still limited. The existing reports mainly focus on two preparation paths: one is to add low-boiling alkanes such as pentane as a physical foaming agent in the reaction system, and to generate a polyurethane with a foam structure by volatilizing the alkanes by heating in the later stage of the reaction; the other is to add polymethylhydrogen siloxane (PMHS) in the reaction system, to achieve foaming by releasing hydrogen gas through the reaction of PMHS with amine compounds, and to use a polyether-siloxane block copolymer (such as TEGOSTAB E8930) as a stabilizer to inhibit bubble merging.
[0006] However, the above methods have obvious limitations: first, both of them need to rely on additional catalysts, foaming agents or stabilizers, and need to control the viscosity of the reaction system during foaming, which not only increases the process complexity and raw material cost, but also introduces the problem of subsequent product separation or residual of the additives; second, the reaction usually needs to be carried out under heating conditions of 50-70℃, which has certain dependence on equipment and high energy consumption; in addition, the foaming process is affected by many factors, especially the residual of the additives, which significantly affects the mechanical properties of the material, resulting in great difficulty in controlling the material performance and poor reproducibility. SUMMARY
[0007] In order to overcome the problems existing in the prior art, the purpose of the present application is to provide a preparation method of porous polyurethane, using multifunctional acrylate and amine compounds containing primary amine groups as raw materials, and ethanol solution as solvent to construct the reaction system, and adjusting the physical and chemical structure of the porous polyurethane by changing the mass ratio of the solvent and the reaction monomer, the structure and molecular weight of the reaction monomer; the preparation method of the present application has high activity at room temperature under natural conditions, and does not need to add additional catalysts, foaming agents and stabilizers, and the synthesis route is simple and environmentally friendly.
[0008] In order to achieve the above purpose, the technical scheme adopted by the present application is: A preparation method of porous polyurethane, comprising the following steps: (1) mixing components A and B after dissolving them in solvent C, and obtaining product PAE1 containing solvent C after a period of reaction; (2) removing solvent C from product PAE1 to obtain the final product PAE2, i.e. porous polyurethane; The component A is a mixture of multifunctional acrylate or multifunctional and difunctional acrylate, the component B is a mixture of amine compounds containing single or multiple primary amine groups and amine compounds containing single and multiple primary amine groups, the solvent C is a single alcohol solvent, a single organic solvent or a mixture of multiple solvents, and PAE is the abbreviation of the product porous polyurethane.
[0009] In addition, the synthesis of PAE2 can not only be used to prepare pure polyurethane foam in a container, but also can be used to prepare porous polyurethane composite material by impregnation and spraying process, in which the mixed solution of components A, B and solvent C is added into the porous substrate, and the multi-level network structure is generated in situ in the porous substrate after a certain reaction time.
[0010] The step (1) is specifically: Step 1): Components A and B are dissolved in solvent C respectively to obtain a uniform mixed solution, i.e. A / C solution and B / C solution; Step 2): The A / C solution and B / C solution obtained in step 1) are mixed and shaken uniformly, and then are placed in a room temperature environment for a period of time to obtain product PAE1 containing solvent C; The multi-functional acrylate structure is one of (1)-(8): The di-functional acrylate structure is one of (9)-(22): The amine compound containing a single primary amine group has a structure of one of (23)-(28): The amine compound containing multiple primary amine groups has a structure of one of (29)-(36): The single alcohol solvent is one of methanol, ethanol, n-butanol, isobutyl alcohol, propylene glycol and isopropyl alcohol; The organic solvent is one of dichloromethane, tetrahydrofuran, 1,4-dioxane, dimethyl sulfoxide and chloroform; The multiple solvent mixture is a mixture of ethanol and water, in which the content of ethanol is 95%-100%; In step (1), the molar ratio of the acrylate group in component A to the primary amine group in component B is 1:1-3, the reaction temperature is room temperature 18-25℃, and the reaction time is 5min-48h. More types of amine and acrylate reactions can be covered, and the higher the functionality of the acrylate and amine compound, the shorter the gelation time.
[0011] The solvent C is used in an amount of 65% to 90% of the total mass of the system, wherein the total mass of the system refers to the total mass of the component A, the component B and the solvent C, and the solvent accounts for 65% to 90%. The prepared sample is a porous polymer material as far as possible. If the amount of the solvent exceeds the range, the prepared sample can be a polymer elastomer.
[0012] The solvent removal method in the step (2) is a room temperature volatilization method and a solvent replacement + freeze drying method, and the specific processing steps include: Step 1): The room temperature volatilization method is used for removing the solvent in the product PAE1 obtained by reacting the component (2), (3) or (4) with an amine compound containing a single primary amine group in a low-boiling-point solvent: the product PAE1 is placed in a well-ventilated and uncontaminated environment, and the reaction solvent is volatilized by itself. After the solvent is removed, the final product PAE2, i.e., a porous polyurethane, is obtained.
[0013] Step 2): The solvent replacement + freeze drying method is used for removing the solvent in the product PAE1 obtained by reacting a multifunctional acrylate except the component (2), (3) or (4) with the amine compound containing multiple primary amine groups in the solvent C: a mixed solution of tert-butyl alcohol and the reaction solvent C used is used for gradient replacement, wherein the content of the tert-butyl alcohol in the mixed solution of the tert-butyl alcohol and the reaction solvent C used is 30%, 60% and 100% respectively, each gradient replacement is performed twice, each replacement is maintained for 8 to 12 hours, after the replacement is completed, the product PAE1 is frozen in a refrigerator for 24 to 72 hours, after the freezing is completed, the product PAE1 is freeze-dried in a freeze dryer for 48 to 72 hours to remove the tert-butyl alcohol, and finally the product PAE2, i.e., a porous polyurethane, is obtained.
[0014] The porous polyurethane prepared by the method is a white solid, and the polymer phase is formed by the fusion of the spherules, the spherules are used as the solid skeleton of the porous material, and the pores between the skeletons are used as the gas phase. The polymer phase is formed by the fusion of the spherules, and the average diameter of the spherules ranges from 1.5 to 10 microns.
[0015] The present application has the following beneficial effects: The present application uses the efficient chemical reaction between the acrylate and the primary amine, uses the different solubility of the products obtained before and after the reaction in the solvent, and synthesizes the porous polyurethane (Porous PAE) by one-pot method at room temperature in a natural environment without catalyst, foaming agent and stabilizer. In addition, the multifunctional acrylate and the amine compound containing single or multiple primary amines used as the reactants in the present application are easy to obtain, have high reactivity, and the reaction solvent is ethanol, which is friendly to the environment.
[0016] The application has high reactivity, simple reaction process, and can realize synthesis of porous polyurethane through one-step reaction in room temperature natural environment.
[0017] The application does not use additional catalysts, does not involve removal of subsequent catalysts, and avoids catalyst residue problems. The application does not use physical or chemical foaming agents and stabilizers, and the obtained product does not involve by-products and the like, and does not need further purification treatment. The solvent used in the application is ethanol and a mixture of ethanol and water (wherein the ethanol content is 95% to 100%), which is environmentally friendly.
[0018] The porous polyurethane prepared by the application has adjustable physical and chemical structures, good compression and rebound performance, and reworkable and degradable characteristics, which endows the material with high designability and processability, so that the material can be "customized" to adapt to more application scenarios, solves the recycling problem after material use, and is environmentally friendly. BRIEF DESCRIPTION OF DRAWINGS
[0019] Figure 1 The physical picture and scanning electron microscope picture of the porous polyurethane prepared for Example 1 are shown in (a) physical picture and (b) scanning electron microscope picture.
[0020] Figure 2 The physical picture and scanning electron microscope picture of the porous polyurethane prepared for Example 7 are shown in (a) physical picture and (b) scanning electron microscope picture.
[0021] Figure 3 The physical picture and scanning electron microscope picture of the porous polyurethane prepared for Example 8 are shown in (a) physical picture and (b) scanning electron microscope picture.
[0022] Figure 4 The physical picture and scanning electron microscope picture of the porous polyurethane prepared for Example 9 are shown in (a) physical picture and (b) scanning electron microscope picture.
[0023] Figure 5 The physical picture and scanning electron microscope picture of the porous polyurethane prepared for Example 10 are shown in (a) physical picture and (b) scanning electron microscope picture.
[0024] Figure 6 The physical picture and scanning electron microscope picture of the porous polyurethane prepared for Example 11 are shown in (a) physical picture and (b) scanning electron microscope picture.
[0025] Figure 7 The physical picture and scanning electron microscope picture of the porous polyurethane prepared for Example 12 are shown in (a) physical picture and (b) scanning electron microscope picture. DETAILED DESCRIPTION
[0026] The application will be further described in detail below with reference to the accompanying drawings.
[0027] Example 1 Component A has structure (3), component B has structure (24), and solvent C is ethanol. To a sample bottle containing 0.29 g of component A, 1 mL of solvent C was added, to a sample bottle containing 0.1 g of component B, 1 mL of solvent C was added, the A / C solution and the B / C solution were mixed respectively, and then mixed together, and the mixed solution was shaken well using a vortex shaker, and then left to stand in a sealed room at room temperature (18°C) for a period of time, after a small amount of solvent was precipitated, a white solid containing C was obtained, and finally the residual solvent C in the product was evaporated in a fume hood, and after the solvent was removed, a porous polyurethane was obtained.
[0028] As shown in Figure 1 , the obtained porous polyurethane is composed of polymer phases formed by the fusion of spherical particles with an average diameter of 5.44 μm, and the solid skeleton of the porous material, and the pores of the solid skeleton form the gas phase. Figure 1 (a) is a physical map, Figure 1 (b) is a scanning electron microscope image.
[0029] Example 2 Component A has structure (3), component B has structure (37), and solvent C is ethanol. To a sample bottle containing 0.37 g of component A, 1 mL of solvent C was added, to a sample bottle containing 0.02 g of component B, 1 mL of solvent C was added, the A / C solution and the B / C solution were mixed respectively, and then mixed together, and the mixed solution was shaken well using a vortex shaker, and then left to stand in a sealed room at room temperature (20°C) for a period of time, after a small amount of solvent was precipitated, a white solid containing C was obtained, and then the solvent C was replaced with 100% t-butanol by solvent gradient replacement, and then frozen in a refrigerator for at least 24 h, and finally dried in a freeze dryer, to obtain a porous polyurethane.
[0030] Example 3 Component A has structures (3) and (31), component B has structure (24), and solvent C is ethanol. To a sample bottle containing 0.49 g of component A with structure (3), 1.4 mL of solvent C was added, to a sample bottle containing 0.02 g of component A with structure (10), 1.4 mL of solvent C was added, to a sample bottle containing 0.17 g of component B, 1 mL of solvent C was added, the A / C solution and the B / C solution were mixed respectively, and then mixed together, and the mixed solution was shaken well using a vortex shaker, and then left to stand in a sealed room at room temperature (23°C) for a period of time, after a small amount of solvent was precipitated, a white solid containing C was obtained, and finally the residual solvent C in the product was evaporated in a fume hood, and after the solvent was removed, a porous polyurethane was obtained.
[0031] Example 4 Component A has structures (3) and (9), component B has structures (24) and (30), and solvent C is ethanol. 2.5 mL of solvent C was added to the sample bottle containing 0.8 g of component A (3) structure, 2.5 mL of solvent C was added to the sample bottle containing 0.8 g of component A (9) structure, 2.5 mL of solvent C was added to the sample bottle containing 0.23 g of component B (24) structure, and 2.5 mL of solvent C was added to the sample bottle containing 0.14 g of component B (30) structure. The four sample bottles were shaken and mixed thoroughly. Then, the mixtures of the two structures of component A and component B were placed into the same sample bottle. The A / C solution and the B / C solution were mixed thoroughly and then combined. The mixture was shaken thoroughly using a vortex shaker. The mixed solution was allowed to stand in a sealed room temperature (21°C) environment for a period of time. After a small amount of solvent precipitated, a white solid containing C was obtained. Finally, the residual solvent C in the product was evaporated in a fume hood. After solvent removal, porous polyurethane was obtained.
[0032] Example 5 Component A has a (3) structure, component B has a (24) structure, and solvent C is dichloromethane. 1 mL of solvent C was added to a sample bottle containing 0.49 g of component A and 1 mL of solvent C was added to a sample bottle containing 0.17 g of component B. The A / C solution and the B / C solution were mixed thoroughly and then mixed. After shaking, the mixed solution was allowed to stand in a sealed room temperature (22℃) environment for a period of time. After a small amount of solvent precipitated, a white solid containing C was obtained. Finally, the residual solvent C in the product was evaporated in a fume hood. After solvent removal, porous polyurethane was obtained.
[0033] Example 6 Component A has a (3) structure, component B has a (24) structure, and solvent C is an ethanol / water mixture with an ethanol content of 95%. 1 mL of solvent C was added to a sample bottle containing 0.29 g of component A and 1 mL of solvent C was added to a sample bottle containing 0.1 g of component B. The A / C solution and the B / C solution were mixed thoroughly and then vortexed. The mixture was allowed to stand in a sealed room temperature (22°C) environment for a period of time. After a small amount of solvent precipitated, a white solid containing C was obtained. Then, solvent C was replaced with 100% tert-butanol by solvent gradient displacement. The mixture was then frozen in a refrigerator for at least 24 hours and finally dried in a freeze dryer to obtain porous polyurethane.
[0034] Example 7 Component A has a (3) structure, component B has a (24) structure, and solvent C is ethanol. 1 mL of solvent C was added to a sample bottle containing 0.39 g of component A and 1 mL of solvent C was added to a sample bottle containing 0.13 g of component B. The A / C solution and the B / C solution were mixed thoroughly and then mixed together. The mixture was shaken and shaken using a vortex shaker. The mixed solution was allowed to stand in a sealed room temperature (18°C) environment for a period of time. After a small amount of solvent precipitated, a white solid containing C was obtained. Finally, the residual solvent C in the product was evaporated in a fume hood. After the solvent was removed, porous polyurethane was obtained.
[0035] like Figure 2 As shown, the obtained porous polyurethane is a polymer phase formed by the fusion of spherical particles with an average diameter of 4.09 μm, which serves as the solid skeleton of the porous material, and the pores of the solid skeleton constitute the gas phase. Figure 2 (a) is a picture of the actual object. Figure 2 (b) is a scanning electron microscope image.
[0036] Example 8 Component A has a (1) structure, component B has a (24) structure, and solvent C is ethanol. 1 mL of solvent C was added to a sample bottle containing 0.30 g of component A and 1 mL of solvent C was added to a sample bottle containing 0.09 g of component B. The A / C solution and the B / C solution were mixed thoroughly and then mixed together. The mixture was shaken and shaken using a vortex shaker. The mixed solution was allowed to stand in a sealed room temperature (18°C) environment for a period of time. After a small amount of solvent precipitated, a white solid containing C was obtained. Solvent C was replaced with 100% tert-butanol by solvent gradient displacement. The solid was then frozen in a refrigerator for at least 24 hours and finally dried in a freeze dryer to obtain porous polyurethane.
[0037] like Figure 3 As shown, the obtained porous polyurethane is a polymer phase formed by the fusion of spherical particles with an average diameter of 3.61 μm, which serves as the solid skeleton of the porous material, and the pores of the solid skeleton constitute the gas phase. Figure 3 (a) is a picture of the actual object. Figure 3 (b) is a scanning electron microscope image.
[0038] Example 9 Component A has a (2) structure, component B has a (24) structure, and solvent C is ethanol. 1 mL of solvent C was added to a sample bottle containing 0.30 g of component A and 1 mL of solvent C was added to a sample bottle containing 0.09 g of component B. The A / C solution and the B / C solution were mixed thoroughly and then mixed together. The mixture was shaken and shaken using a vortex shaker. The mixed solution was allowed to stand in a sealed room temperature (18°C) environment for a period of time. After a small amount of solvent precipitated, a white solid containing C was obtained. Finally, the residual solvent C in the product was evaporated in a fume hood. After the solvent was removed, porous polyurethane was obtained.
[0039] like Figure 4 As shown, the obtained porous polyurethane is a polymer phase formed by the fusion of spherical particles with an average diameter of 7.94 μm, which serves as the solid skeleton of the porous material, and the pores of the solid skeleton constitute the gas phase. Figure 4 (a) is a picture of the actual object. Figure 4 (b) is a scanning electron microscope image.
[0040] Example 10 Component A has a (5) structure, component B has a (24) structure, and solvent C is ethanol. 1 mL of solvent C was added to a sample bottle containing 0.30 g of component A and 1 mL of solvent C was added to a sample bottle containing 0.09 g of component B. The A / C solution and the B / C solution were mixed thoroughly and then mixed together. The mixture was shaken and shaken using a vortex shaker. The mixed solution was allowed to stand in a sealed room temperature (22°C) environment for a period of time. After a small amount of solvent precipitated, a white solid containing C was obtained. Solvent C was replaced with 100% tert-butanol by solvent gradient displacement. The solid was then frozen in a refrigerator for at least 24 hours and finally dried in a freeze dryer to obtain porous polyurethane.
[0041] like Figure 5 As shown, the obtained porous polyurethane is a polymer phase formed by the fusion of spherical particles with an average diameter of 2.06 μm, which serves as the solid skeleton of the porous material, and the pores of the solid skeleton constitute the gas phase. Figure 5 (a) is a picture of the actual object. Figure 5 (b) is a scanning electron microscope image.
[0042] Example 11 Component A has a (3) structure, component B has a (24) structure, and solvent C is ethanol. 1 mL of solvent C was added to a sample bottle containing 0.50 g of component A and 1 mL of solvent C was added to a sample bottle containing 0.17 g of component B. The A / C solution and the B / C solution were mixed thoroughly and then mixed together. The mixture was shaken and shaken using a vortex shaker. The mixed solution was allowed to stand in a sealed room temperature (18°C) environment for a period of time. After a small amount of solvent precipitated out, a white solid containing C was obtained. Finally, the residual solvent C in the product was evaporated in a fume hood. After the solvent was removed, porous polyurethane was obtained.
[0043] like Figure 6 As shown, the obtained porous polyurethane is a polymer phase composed of stacked rod-shaped structures with an average diameter of 1.51 μm, which serves as the solid skeleton of the porous material, and the pores of the solid skeleton constitute the gas phase. Figure 6 (a) is a picture of the actual object. Figure 6 (b) is a scanning electron microscope image.
[0044] Example 12 Component A has a (3) structure, component B has a (24) structure, and solvent C is ethanol. 1 mL of solvent C was added to a sample bottle containing 0.63 g of component A and 1 mL of solvent C was added to a sample bottle containing 0.22 g of component B. The A / C solution and the B / C solution were mixed thoroughly and then mixed together. The mixture was shaken and shaken using a vortex shaker. The mixed solution was allowed to stand in a sealed room temperature (18°C) environment for a period of time. After a small amount of solvent precipitated out, a white solid containing C was obtained. Finally, the residual solvent C in the product was evaporated in a fume hood. After the solvent was removed, porous polyurethane was obtained.
[0045] like Figure 7 As shown, the obtained porous polyurethane is a polymer phase formed by the fusion of coral-like and rod-like structures, which serves as the solid skeleton of the porous material, and the pores of the solid skeleton constitute the gas phase. Figure 7 (a) is a picture of the actual object. Figure 7 (b) is a scanning electron microscope image.
[0046] Example 13 Component A has (3) and (10) structures, component B has (24) structure, and solvent C is ethanol. 1.4 mL of solvent C was added to the sample bottle containing 0.49 g of component A with (3) structure, 1.4 mL of solvent C was added to the sample bottle containing 0.02 g of component A with (10) structure, and 1 mL of solvent C was added to the sample bottle containing 0.17 g of component B. The A / C solution and the B / C solution were mixed evenly and then mixed. After shaking, the mixed solution was allowed to stand in a sealed room temperature (23℃) for a period of time. After a small amount of solvent precipitated, a white solid containing C was obtained. Most of the ethanol was then evaporated in a fume hood, and then further dried in a vacuum drying oven to obtain porous polyurethane.
Claims
1. A method for preparing a porous polyurethane, characterized in that, Includes the following steps; (1) Dissolve components A and B in solvent C respectively and mix them. After reacting for a period of time, product PAE1 containing solvent C is obtained. (2) After removing solvent C from product PAE1, the final product PAE2, namely porous polyurethane, is obtained. Component A is a polyfunctional acrylate or a mixture of polyfunctional and difunctional acrylates; Component B is an amine compound containing one or more primary amine groups and a mixture of amine compounds containing one or more primary amine groups; solvent C is a single alcohol solvent, a single organic solvent, or a mixture of multiple solvents.
2. The method for preparing a porous polyurethane according to claim 1, characterized in that, The specific steps (1) are as follows: Step 1): Dissolve component A and component B in solvent C respectively to obtain a homogeneous mixture, namely A / C solution and B / C solution; Step 2): Mix the A / C solution and B / C solution obtained in Step 1), shake well, and let stand at room temperature for a period of time to obtain product PAE1 containing solvent C.
3. The method for preparing a porous polyurethane according to claim 1, characterized in that, The multifunctional acrylate structure is one of (1)-(8): The difunctional acrylate structure is one of (9)-(22): 。 4. The method for preparing a porous polyurethane according to claim 1, characterized in that, The amine compound containing a single primary amine group has one of the structures of (23)-(28): The amine compound containing multiple primary amine groups has one of the structures of (30)-(37): 。 5. The method for preparing a porous polyurethane according to claim 1, characterized in that, The single alcohol solvent is one of methanol, ethanol, n-butanol, isobutanol, propylene glycol, and isopropanol; The organic solvent is one of dichloromethane, tetrahydrofuran, 1,4-dioxane, dimethyl sulfoxide, and trichloromethane; The mixture of multiple solvents is a mixture of ethanol and water, wherein the ethanol content is 95%~100%.
6. The method for preparing a porous polyurethane according to claim 1, characterized in that, In step (1), the molar ratio of acrylate groups in component A to primary amine groups in component B is 1:1~3, the reaction temperature is room temperature (18~25℃), and the reaction time is 5min~48h.
7. The method for preparing a porous polyurethane according to claim 1, characterized in that, In step (1), the amount of solvent C used is 65% to 90% of the total mass of the system. The total mass of the system refers to the total mass of component A, component B and solvent C, of which the solvent accounts for 65% to 90%.
8. The method for preparing a porous polyurethane according to claim 1, characterized in that, The solvent removal methods in step (2) are room temperature evaporation and solvent replacement + freeze-drying. The specific processing steps include: Step 1): Room temperature evaporation method for removing the solvent from product PAE1 containing components (2), (3) or (4) and amine compounds containing a single primary amine group in a low boiling point solvent: Place product PAE1 in a well-ventilated and pollution-free environment to allow the reaction solvent to evaporate on its own. After solvent removal, the final product PAE2, i.e., porous polyurethane, is obtained. Step 2): Solvent replacement + freeze-drying method for removing solvent from product PAE1 obtained by reacting multifunctional acrylates (excluding those containing components (2), (3) or (4)) with amine compounds containing multiple primary amine groups in solvent C: Gradient replacement is performed using a mixed solution of tert-butanol and the reaction solvent C, wherein the contents of tert-butanol in the mixed solution of tert-butanol and the reaction solvent C are 30%, 60% and 100%, respectively. Each gradient replacement is performed twice, and each replacement is maintained for 8h~12h. After the replacement is completed, product PAE1 is placed in a refrigerator and frozen for 24~72h. After freezing, it is freeze-dried in a freeze dryer for 48~72h to remove tert-butanol, and finally product PAE2, namely porous polyurethane, is obtained.
9. A porous polyurethane prepared by the method according to any one of claims 1-8, characterized in that, It is a white solid, which forms a polymer phase through varying degrees of fusion between particles, serving as the solid framework of the porous material, while the pores between the framework serve as the gas phase. Its polymer phase is formed by the fusion of spheres, with an average diameter of 1.5~10μm.