Soft waterproof nanofiber membrane and preparation method thereof
A soft, waterproof nanofiber membrane was prepared by electrospinning and heat treatment of waterborne polyurethane emulsion and modified composite particles, which solved the environmental and health hazards of traditional preparation methods and achieved high-performance waterproof and breathable effects.
Patent Information
- Application Number
- CN202510979062.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-16
- Publication Date
- 2025-10-28
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
The use of organic solvents in the traditional electrospun nanofiber membrane preparation process poses hazards to the environment and human health, and also results in insufficient performance.
A soft, waterproof nanofiber membrane was prepared by electrospinning and heat treatment using waterborne polyurethane emulsion and modified composite particles. The hydrophobicity was enhanced by crosslinking of trimethylolpropane tris(2-methyl-1-azacyclopropane propionate) and thermally induced migration of silicon segments, and the mechanical properties were improved by introducing ZrO2 and SiO2 modified particles.
The prepared soft and waterproof nanofiber membrane has good hydrophobicity, air permeability and mechanical properties, avoids the use of toxic solvents, and improves the tensile strength and thermal stability of the fiber membrane.
Smart Images
Figure CN120844288A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of textile technology, specifically relating to a soft, waterproof nanofiber membrane and its preparation method. Background Technology
[0002] Electrospinning is a technique that uses a high-voltage electrostatic field to stretch polymer solutions or melts into nanofibers, which can then be used to obtain nanofiber membranes. Waterproof and breathable fabrics are functional textiles that can block liquid water penetration while allowing water vapor (sweat evaporation) to pass through. Their core characteristics are high water pressure resistance and high moisture permeability, making them widely used in outdoor clothing, medical protective equipment, and sports gear. Nanofiber membranes obtained through electrospinning can be applied to fabrics to improve their waterproof and breathable properties.
[0003] However, most traditional electrospun nanofiber membranes are prepared using organic solvents, which pose certain hazards to the environment and human health. Therefore, there is a need for an environmentally friendly nanofiber membrane with good performance. Summary of the Invention
[0004] The purpose of this invention is to provide a soft, waterproof nanofiber membrane and its preparation method, in order to solve the technical problems in the prior art.
[0005] To achieve the above objectives, the present invention adopts the following technical solution:
[0006] This invention provides a method for preparing a soft, waterproof nanofiber membrane, comprising the following steps:
[0007] Step (1) Polyethylene glycol, trimethylolpropane tris(2-methyl-1-azacyclopropane propionate), and modified composite particles are added to the modified polyurethane emulsion. After adding water, the mixture is stirred to obtain the spinning solution.
[0008] Step (2) The spinning solution is loaded into a syringe, and electrospinning is performed using aluminum foil as the substrate. Then, heat treatment is performed to obtain a soft and waterproof nanofiber membrane.
[0009] In the above process, heat treatment promotes the full crosslinking of trimethylolpropane tris(2-methyl-1-azacyclopropane propionate) with waterborne polyurethane, while thermal induction causes low surface energy silicon segments to migrate to the fiber surface to enhance hydrophobicity and obtain a soft and waterproof nanofiber membrane.
[0010] Preferably, in step (1), the ratio of polyethylene glycol, trimethylolpropane tris(2-methyl-1-azacyclopropane propionate), modified composite particles, modified polyurethane emulsion, and water is 0.8-1.6:0.2-0.4:0.4-0.8:20-40:15-30; the stirring conditions are: stirring time of 2-3 hours and stirring speed of 400-600 r / min.
[0011] Preferably, in step (2), the electrospinning conditions are as follows: spinning temperature is 28-32℃, spinning humidity is 30-40%, receiving distance is 25-27cm, spinning voltage is 28-32kV, spinning speed is 0.1-0.2mm / min; fiber membrane thickness is 0.06-0.07mm; heat treatment time is 1.5-2.5h, and heat treatment temperature is 60-70℃.
[0012] Preferably, in step (1), the method for preparing the modified composite particles includes the following steps:
[0013] P1: Nano ZrO2 and water were added to anhydrous ethanol, then acetic acid was added, and the mixture was sonicated. Then, tetraethyl orthosilicate was added dropwise, stirred, and stirred again. After centrifugation, the mixture was washed and dried to obtain composite particles. The composite particles and hexamethyldisilazane were added to ethanol, mixed and stirred, centrifuged and dried, and then ground to obtain hydrophobic composite particles.
[0014] In the above process, SiO2 is coated on the surface of ZrO2, and the surface of the composite particles is modified with hexamethyldisilazane to increase hydrophobicity.
[0015] P2: Disperse the hydrophobic composite particles in an ethanol aqueous solution, add KH-550, react, centrifuge, wash, and dry to obtain the modified composite particles.
[0016] In the above process, hexamethyldisilazane is hydrophobically modified and then modified with a small amount of KH-550 to improve its compatibility with waterborne polyurethane.
[0017] Preferably, in P1, the ultrasonic treatment conditions are as follows: ultrasonic treatment time is 2-3 hours, ultrasonic treatment power is 200-300W; the ratio of nano ZrO2, water, anhydrous ethanol, acetic acid, tetraethyl orthosilicate, hexamethyldisilazane, and ethanol is 25-50g:0.5-1mL:300-600mL:1-2mL:20-30mL:4-8mL:300-600mL; the stirring time is 0.5-1 hour; the re-stirring treatment conditions are as follows: re-stirring treatment temperature is 55-65℃, re-stirring treatment speed is 500-800rpm, and re-stirring treatment time is 6-8 hours; the washing method is: washing with ethanol and water 3-5 times respectively; the mixing and stirring time is 2-3 hours; and the grinding particle size is 100-150nm.
[0018] Preferably, in P2, the ratio of hydrophobic composite particles, ethanol aqueous solution, and KH-550 is 10-20g:120-240mL:0.05-0.1g; the ethanol aqueous solution has a volume ratio of ethanol to water of 9:1; the reaction conditions are: reaction temperature of 55-65℃ and reaction time of 3-5h.
[0019] Preferably, in step (1), the method for preparing the modified polyurethane emulsion includes the following steps:
[0020] S1: Hydroxyl-terminated polybutadiene and mercaptofuran were added to N-methylpyrrolidone, irradiated with blue light, and precipitated to obtain grafted hydroxyl-terminated polybutadiene.
[0021] In the above process, the reaction between the thiol group of mercaptofuran and the double bond of the hydroxyl-terminated polybutadiene is initiated by light.
[0022] The structural formula of grafted hydroxyl-terminated polybutadiene is as follows:
[0023]
[0024] S2: Hydroxyl-terminated polydimethylsiloxane and 4-methyl-m-phenylene diisocyanate were added to toluene, followed by the addition of dibutyltin dilaurate. The mixture was stirred and treated, and then N-(2-hydroxyethyl)maleimide and dibutyltin dilaurate were added. The reaction was continued, and impurities were removed to obtain grafted hydroxyl-terminated polydimethylsiloxane.
[0025] In the above process, the terminal hydroxyl groups of the hydroxyl-terminated polydimethylsiloxane react with the isocyanate groups of 4-methyl-m-phenylene diisocyanate to obtain an intermediate with terminal isocyanate groups. Then, the isocyanate groups react with the hydroxyl groups of N-(2-hydroxyethyl)maleimide to obtain the grafted hydroxyl-terminated polydimethylsiloxane.
[0026] S3: Add grafted hydroxyl polybutadiene and grafted hydroxyl polydimethylsiloxane to toluene and stir to obtain a dihydroxy polymer;
[0027] The structural formula of the dihydroxy polymer is as follows:
[0028]
[0029] S4: Mix polytetrahydrofuran ether diol, isophorone diisocyanate and dihydroxy polymer, preheat, raise the temperature, add bismuth 2-ethylhexanoate to continue the reaction, then add 2,2-dimethylolpropionic acid to continue the reaction, cool down, add triethanolamine to neutralize, and obtain a prepolymer. Pour the prepolymer into deionized water and shear disperse to obtain a modified polyurethane emulsion.
[0030] In the above process, polytetrahydrofuran ether diol and dihydroxy polymer together serve as the soft segment of waterborne polyurethane, introducing dihydroxy polymer with low surface energy.
[0031] Preferably, in S1, the ratio of hydroxyl-terminated polybutadiene, mercaptofuran, N-methylpyrrolidone, Ru(bpy)3Cl2, and p-toluidine is 54-108g:114-228g:60-120mL:55-110mg:2-4g; the blue light irradiation method is: irradiation with blue light at 25°C with a wavelength of 450-495nm and a power of 7W for 10-12h; the precipitation method is: precipitation in methanol after concentration.
[0032] Preferably, in step S2, the ratio of hydroxyl-terminated polydimethylsiloxane, 4-methyl-m-phenylene diisocyanate, toluene, dibutyltin dilaurate, N-(2-hydroxyethyl)maleimide, and dibutyltin dilaurate is 110-220g:8.8-17.6g:80-160mL:0.3-0.6g:7.1-14.2g:0.3-0.6g; the stirring treatment method is to stir at 55-65℃ for 6-8h; the reaction time is continued for 10-14h; the impurity removal method is to remove toluene by rotary evaporation.
[0033] Preferably, in step S3, the ratio of grafted hydroxyl polybutadiene, grafted hydroxyl polydimethylsiloxane, and toluene is 20-30g:54-108g:80-160mL; the stirring conditions are: stirring temperature of 70-80℃ and stirring time of 20-28h.
[0034] Preferably, in step S4, the ratio of polytetrahydrofuran ether diol, isophorone diisocyanate, dihydroxy polymer, bismuth 2-ethylhexanoate, 2,2-dimethylolpropionic acid, triethanolamine, and deionized water is 49.6-100g:16.7-33g:6-12g:0.25-0.5g:4-8g:4.8-9.6g:120-240mL; the preheating method is: preheating at 70-80℃ for 0.4-0.6h; the heating temperature is 85-91℃; the reaction time is 1-2h; the reaction time is 2-4h; the cooling temperature is 40-50℃; the neutralization time is 8-12min; and the shear dispersion conditions are: shear dispersion rate of 1100-1500r / min and shear dispersion time of 20-40min.
[0035] The soft and waterproof nanofiber membrane prepared by the aforementioned method is described.
[0036] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:
[0037] 1. In this invention, waterborne polyurethane uses water as the dispersion medium, avoiding the use of toxic solvents and meeting green textile standards.
[0038] 2. The soft, waterproof nanofiber membrane prepared by this invention utilizes waterborne polyurethane to regulate the ratio of hydrophilic / hydrophobic segments, introduces siloxane segments to enhance the flexibility and hydrophobicity of the emulsion, and combines this with a heat treatment process to create nanofibers with a surface rich in hydrophobic groups, forming stable interconnected channels between fibers. This results in a membrane with both small pore size and high porosity, enabling efficient transfer of air and water vapor while effectively blocking liquid water penetration. The modification of hexamethyldisilazane with composite particles increases the water contact angle and improves washability, with each component synergistically enhancing the hydrophobicity of the nanofiber membrane.
[0039] 3. This invention involves adding trimethylolpropane tris(2-methyl-1-azacyclopropane propionate) after heat treatment, causing crosslinking between the trimethylolpropane tris(2-methyl-1-azacyclopropane propionate) in the fiber membrane and the waterborne polyurethane. Simultaneously, thermal induced breakage of the DA bonds promotes the migration of silicon segments to the fiber surface, enhancing hydrophobicity. Dynamic urethane bonds (DA bonds) facilitate siloxane migration, reducing intermolecular forces between polyurethane molecules on the nanofiber surface, thus enhancing the mechanical properties of the fiber membrane. Furthermore, the rigidity and high hardness of ZrO2 increase the tensile strength of the fiber, improving the tensile strength and modulus of the fiber membrane and reducing deformation under stress. The Si-O-Si crosslinking points enhance the intermolecular forces of the waterborne polyurethane molecules, preventing fiber breakage. The SiO2 coating layer buffers the rigidity of ZrO2, preventing brittle fracture and increasing the thermal decomposition temperature of the fiber membrane. The amino groups of the modified composite particles are covalently crosslinked with the polyurethane, reducing interfacial slippage and increasing the modulus. All components synergistically enhance the mechanical properties of the nanofiber membrane. Composite ZnO / TiO2 nanoparticles provide excellent UV protection and improve the durability of fiber membranes. Attached Figure Description
[0040] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0041] Figure 1 This is a process flow diagram for preparing the soft, waterproof nanofiber membrane of the present invention;
[0042] Figure 2 This is a bar graph illustrating the water resistance and breathability of the soft, waterproof nanofiber membrane of the present invention. Detailed Implementation
[0043] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.
[0044] The substances and sources involved in the following examples and comparative examples are shown in Table 1:
[0045] Table 1
[0046]
[0047]
[0048] Example 1
[0049] This embodiment discloses a method for preparing modified composite particles, including the following steps:
[0050] P1: Add 38g of nano ZrO2 and 0.75mL of water to 450mL of anhydrous ethanol, then add 1.5mL of acetic acid. After sonication at 250W for 2.5h, add 25mL of tetraethyl orthosilicate dropwise and stir for 0.75h. Then, stir at 650rpm at 60℃ for 7h. After centrifugation, wash the precipitate with ethanol and water four times each, and dry to obtain composite particles. Add the composite particles and 6mL of hexamethyldisilazane to 450mL of ethanol and stir for 2.5h. After centrifugation and drying, grind to obtain hydrophobic composite particles.
[0051] P2: Disperse 10-20g of hydrophobic composite particles in 180mL of ethanol aqueous solution with a volume ratio of 9:1, add 0.075g of KH-550, react at 60℃ for 4h, centrifuge, wash, and dry to obtain modified composite particles.
[0052] Example 2
[0053] This embodiment discloses a method for preparing a modified polyurethane emulsion, including the following steps:
[0054] S1: Add 81g of hydroxyl-terminated polybutadiene and 171g of mercaptofuran to 80mL of N-methylpyrrolidone, then add 83mg of Ru(bpy)3Cl2 and 3g of p-toluidine. Irradiate with blue light at 25℃ for 11h at a wavelength of 470nm and a power of 7W. After concentration, precipitate in methanol to obtain grafted hydroxyl-terminated polybutadiene.
[0055] S2: 165g of hydroxyl-terminated polydimethylsiloxane and 13.2g of 4-methyl-m-phenylene diisocyanate were added to 120mL of toluene, followed by 0.45g of dibutyltin dilaurate. The mixture was stirred at 60℃ for 7h, then 10.7g of N-(2-hydroxyethyl)maleimide and 0.45g of dibutyltin dilaurate were added, and the reaction was continued for 12h. Toluene was removed by rotary evaporation to obtain the grafted hydroxyl-terminated polydimethylsiloxane.
[0056] S3: Add 25g of grafted hydroxyl polybutadiene and 81g of grafted hydroxyl polydimethylsiloxane to 120mL of toluene and stir at 75℃ for 24h to obtain a dihydroxy polymer.
[0057] S4: Mix 75g of polytetrahydrofuran ether diol, 25.1g of isophorone diisocyanate and 9g of dihydroxy polymer, preheat at 75℃ for 0.5h, then raise the temperature to 88℃, add 0.35g of bismuth 2-ethylhexanoate and continue the reaction for 1.5h, then add 6g of 2,2-dimethylolpropionic acid and react for 3h. After the temperature drops to 45℃, add 6.2g of triethanolamine to neutralize for 10min to obtain the prepolymer. Pour the prepolymer into 180mL of deionized water using the direct dispersion method and disperse at a shear rate of 1300r / min for 30min to obtain the modified polyurethane emulsion.
[0058] Example 3
[0059] See Figure 1 As shown in the figure, this embodiment discloses a method for preparing a soft, waterproof nanofiber membrane, including the following steps:
[0060] Step (1) Add 1.2g polyethylene glycol, 0.3g trimethylolpropane tris(2-methyl-1-azacyclopropane propionate), and 0.6g modified composite particles to 30g modified polyurethane emulsion, add 21g water, and stir at 500r / min for 2.5h to obtain spinning solution;
[0061] Step (2) The spinning solution is loaded into a syringe, and electrospinning is performed using aluminum foil as the substrate. Then, heat treatment is performed to obtain a soft and waterproof nanofiber membrane.
[0062] Spinning conditions: spinning temperature 30℃, spinning humidity 35%, receiving distance 26cm, spinning voltage 30kV, spinning speed 0.15mm / min; fiber membrane thickness 0.06mm; heat treatment time 2h, heat treatment temperature 65℃.
[0063] The resulting soft, waterproof nanofiber membrane has a tensile strength of over 9.31 MPa and an elongation of 40.15%.
[0064] Example 4
[0065] See Figure 1 As shown in the figure, this embodiment discloses a method for preparing a soft, waterproof nanofiber membrane, including the following steps:
[0066] Step (1) Add 0.8g polyethylene glycol, 0.4g trimethylolpropane tris(2-methyl-1-azacyclopropane propionate), and 0.4g modified composite particles to 40g modified polyurethane emulsion, add 15g water, and stir at 600r / min for 2h to obtain spinning solution;
[0067] Step (2) The spinning solution is loaded into a syringe, and electrospinning is performed using aluminum foil as the substrate. Then, heat treatment is performed to obtain a soft and waterproof nanofiber membrane.
[0068] Spinning conditions: spinning temperature 32℃, spinning humidity 30%, receiving distance 27cm, spinning voltage 28kV, spinning speed 0.2mm / min; fiber membrane thickness 0.06mm; heat treatment time 2.5h, heat treatment temperature 60℃.
[0069] The resulting soft, waterproof nanofiber membrane has a tensile strength of over 8.69 MPa and an elongation of 41.15%.
[0070] Example 5
[0071] See Figure 1 As shown in the figure, this embodiment discloses a method for preparing a soft, waterproof nanofiber membrane, including the following steps:
[0072] Step (1) Add 1.6g polyethylene glycol, 0.2g trimethylolpropane tris(2-methyl-1-azacyclopropane propionate), and 0.8g modified composite particles to 20g modified polyurethane emulsion, add 30g water, and stir at 400r / min for 3h to obtain spinning solution.
[0073] Step (2) The spinning solution is loaded into a syringe, and electrospinning is performed using aluminum foil as the substrate. Then, heat treatment is performed to obtain a soft and waterproof nanofiber membrane.
[0074] Spinning conditions: spinning temperature 28℃, spinning humidity 40%, receiving distance 25cm, spinning voltage 32kV, spinning speed 0.1mm / min; fiber membrane thickness 0.07mm; heat treatment time 1.5h, heat treatment temperature 70℃.
[0075] The resulting soft, waterproof nanofiber membrane has a tensile strength of over 9.79 MPa and an elongation of 40.39%.
[0076] Comparative Example 1
[0077] Compared with Example 3, Comparative Example 1 did not add modified composite particles during the preparation of the soft waterproof nanofiber membrane, and all other conditions remained unchanged.
[0078] The obtained soft and waterproof nanofiber membrane has a tensile strength of 4.21 MPa and an elongation of 31.39%.
[0079] Comparative Example 2
[0080] Compared with Example 3, in the process of preparing the soft waterproof nanofiber membrane, the modified composite particles in Comparative Example 2 were replaced with nano ZrO2, while other conditions remained unchanged.
[0081] The obtained soft and waterproof nanofiber membrane has a tensile strength of 5.21 MPa and an elongation of 33.69%.
[0082] Comparative Example 3
[0083] Compared with Example 3, in the process of preparing the soft waterproof nanofiber membrane, the modified composite particles in Comparative Example 2 were replaced with nano-SiO2, while other conditions remained unchanged.
[0084] The obtained soft, waterproof nanofiber membrane has a tensile strength of 5.42 MPa and an elongation of 34.19%.
[0085] Comparative Example 4
[0086] Compared with Example 3, Comparative Example 4 used commercially available waterborne polyurethane instead of modified polyurethane emulsion in the process of preparing the soft waterproof nanofiber membrane, while keeping other conditions unchanged.
[0087] The resulting soft, waterproof nanofiber membrane has a tensile strength of over 5.97 MPa and an elongation of 30.97%.
[0088] Experimental example
[0089] The properties of the flexible waterproof nanofiber membranes prepared in Examples 3-5 and Comparative Examples 1-4 were tested:
[0090] Hydrophobicity was tested in 2 μL of water using a contact angle (CA) tester (DSA25S KRUSS, Germany); moisture permeability was tested according to ISO 2528; water pressure resistance was tested according to ISO 811; and air permeability was tested according to GB / T5453-1997. The test results are shown in Table 2.
[0091] Table 2
[0092]
[0093] From Examples 3-5 and Comparative Examples 1-4, it can be seen that the soft waterproof nanofiber membrane prepared in Example 3 of the present invention has good air permeability, moisture permeability, waterproofness, and mechanical properties. A comparison of Comparative Examples 1-3 and Examples 3-6 shows that in the process of preparing the soft waterproof nanofiber membrane, the absence of modified composite particles, the use of nano-ZrO2 as the modified composite particles, and the replacement of the modified composite particles with nano-SiO2 all lead to a deterioration in the overall performance of the soft waterproof nanofiber membrane. A comparison of Comparative Example 4 and Examples 3-5 shows that in the process of preparing the soft waterproof nanofiber membrane, the use of commercially available waterborne polyurethane instead of modified polyurethane emulsion leads to a deterioration in the overall performance of the soft waterproof nanofiber membrane.
[0094] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.
[0095] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to specific implementations. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.
Claims
1. A method for preparing a soft, waterproof nanofiber membrane, characterized in that, Includes the following steps: Step (1) Polyethylene glycol, trimethylolpropane tris(2-methyl-1-azacyclopropane propionate), and modified composite particles are added to the modified polyurethane emulsion. After adding water, the mixture is stirred to obtain the spinning solution. Step (2) The spinning solution is loaded into a syringe, and electrospinning is performed using aluminum foil as the substrate. Then, heat treatment is performed to obtain a soft and waterproof nanofiber membrane.
2. The method for preparing the soft, waterproof nanofiber membrane according to claim 1, characterized in that, In step (1), the ratio of polyethylene glycol, trimethylolpropane tris(2-methyl-1-azacyclopropane propionate), modified composite particles, modified polyurethane emulsion, and water is 0.8-1.6:0.2-0.4:0.4-0.8:20-40:15-30; the stirring conditions are: stirring time of 2-3 hours and stirring speed of 400-600 r / min. In step (2), the electrospinning conditions are as follows: spinning temperature is 28-32℃, spinning humidity is 30-40%, receiving distance is 25-27cm, spinning voltage is 28-32kV, spinning speed is 0.1-0.2mm / min; fiber membrane thickness is 0.06-0.07mm; heat treatment time is 1.5-2.5h, and heat treatment temperature is 60-70℃.
3. The method for preparing the soft, waterproof nanofiber membrane according to claim 1, characterized in that, The method for preparing the modified composite particles in step (1) includes the following steps: P1: Nano ZrO2 and water were added to anhydrous ethanol, then acetic acid was added, and the mixture was sonicated. Then, tetraethyl orthosilicate was added dropwise, stirred, and stirred again. After centrifugation, the mixture was washed and dried to obtain composite particles. The composite particles and hexamethyldisilazane were added to ethanol, mixed and stirred, centrifuged and dried, and then ground to obtain hydrophobic composite particles. P2: Disperse the hydrophobic composite particles in an ethanol aqueous solution, add KH-550, react, centrifuge, wash, and dry to obtain the modified composite particles.
4. The method for preparing the soft, waterproof nanofiber membrane according to claim 3, characterized in that, In P1, the ultrasonic treatment conditions are as follows: ultrasonic treatment time is 2-3 hours, ultrasonic treatment power is 200-300W; the ratio of nano ZrO2, water, anhydrous ethanol, acetic acid, tetraethyl orthosilicate, hexamethyldisilazane, and ethanol is 25-50g:0.5-1mL:300-600mL:1-2mL:20-30mL:4-8mL:300-600mL; the stirring time is 0.5-1 hour; the re-stirring treatment conditions are as follows: re-stirring treatment temperature is 55-65℃, re-stirring treatment speed is 500-800rpm, and re-stirring treatment time is 6-8 hours; the washing method is: washing with ethanol and water 3-5 times respectively; the mixing and stirring time is 2-3 hours; the grinding particle size is 100-150nm.
5. The method for preparing the soft, waterproof nanofiber membrane according to claim 3, characterized in that, In P2, the ratio of hydrophobic composite particles, ethanol aqueous solution, and KH-550 is 10-20g:120-240mL:0.05-0.1g; the ethanol aqueous solution has a volume ratio of ethanol to water of 9:1; the reaction conditions are: reaction temperature of 55-65℃ and reaction time of 3-5h.
6. The method for preparing the soft, waterproof nanofiber membrane according to claim 1, characterized in that, In step (1), the method for preparing the modified polyurethane emulsion includes the following steps: S1: Hydroxyl-terminated polybutadiene and mercaptofuran were added to N-methylpyrrolidone, irradiated with blue light, and precipitated to obtain grafted hydroxyl-terminated polybutadiene. S2: Hydroxyl-terminated polydimethylsiloxane and 4-methyl-m-phenylene diisocyanate were added to toluene, followed by the addition of dibutyltin dilaurate. The mixture was stirred and treated, and then N-(2-hydroxyethyl)maleimide and dibutyltin dilaurate were added. The reaction was continued, and impurities were removed to obtain grafted hydroxyl-terminated polydimethylsiloxane. S3: Add grafted hydroxyl polybutadiene and grafted hydroxyl polydimethylsiloxane to toluene and stir to obtain a dihydroxy polymer; S4: Mix polytetrahydrofuran ether diol, isophorone diisocyanate and dihydroxy polymer, preheat, raise the temperature, add bismuth 2-ethylhexanoate to continue the reaction, then add 2,2-dimethylolpropionic acid to continue the reaction, cool down, add triethanolamine to neutralize, and obtain a prepolymer. Pour the prepolymer into deionized water and shear disperse to obtain a modified polyurethane emulsion.
7. The method for preparing the soft, waterproof nanofiber membrane according to claim 6, characterized in that, In S1, the ratio of hydroxyl-terminated polybutadiene, mercaptofuran, N-methylpyrrolidone, Ru(bpy)3, and Cl2-toluidine is 54-108g:114-228g:60-120mL:55-110mg:2-4g; the blue light irradiation method is to irradiate with blue light at 25℃ with a wavelength of 450-495nm and a power of 7W for 10-12h; the precipitation method is to precipitate in methanol after concentration. In S2, the ratio of hydroxyl-terminated polydimethylsiloxane, 4-methyl-m-phenylene diisocyanate, toluene, dibutyltin dilaurate, N-(2-hydroxyethyl)maleimide, and dibutyltin dilaurate is 110-220g:8.8-17.6g:80-160mL:0.3-0.6g:7.1-14.2g:0.3-0.6g; the stirring treatment method is to stir at 55-65℃ for 6-8h; the reaction time is continued for 10-14h; the impurity removal method is to remove toluene by rotary evaporation.
8. The method for preparing the flexible waterproof nanofiber membrane according to claim 6, characterized in that, In step S3, the ratio of grafted hydroxyl polybutadiene, grafted hydroxyl polydimethylsiloxane, and toluene is 20-30g:54-108g:80-160mL; the stirring conditions are: stirring temperature of 70-80℃ and stirring time of 20-28h.
9. The method for preparing the flexible waterproof nanofiber membrane according to claim 6, characterized in that, In S4, the ratio of polytetrahydrofuran ether diol, isophorone diisocyanate, dihydroxy polymer, bismuth 2-ethylhexanoate, 2,2-dimethylolpropionic acid, triethanolamine, and deionized water is 49.6-100g:16.7-33g:6-12g:0.25-0.5g:4-8g:4.8-9.6g:120-240mL; the preheating method is: preheating at 70-80℃ for 0.4-0.6h; the heating temperature is 85-91℃; the reaction time is 1-2h; the reaction time is 2-4h; the cooling temperature is 40-50℃; the neutralization time is 8-12min; the shear dispersion conditions are: shear dispersion rate of 1100-1500r / min and shear dispersion time of 20-40min.
10. A soft, waterproof nanofiber membrane prepared by the method according to any one of claims 1-9.