Nanofiber membrane with waterproof, breathable and radiative refrigeration, preparation method and application thereof

Abstract

The application relates to the technical field of nanofiber membrane materials, in particular to a nanofiber membrane with waterproof, breathable and radiation refrigeration functions, a preparation method and application thereof. The preparation method of the nanofiber membrane with waterproof, breathable and radiation refrigeration functions comprises the following steps: S1, spinning solution preparation: a thermoplastic polyurethane (TPU) polymer is dissolved in a composite organic solvent, after stirring and dissolving, polydimethylsiloxane (PDMS) is added, and inorganic nanoparticles are continuously added after stirring and dissolving, and the spinning solution is obtained; S2, nanofiber membrane preparation: the spinning solution of S1 is electrospun, and the nanofiber membrane is dried after spinning. The fiber membrane has the advantages of high elasticity, waterproofness and breathability while being capable of being cooled.

Description

Technical Field

[0001] This invention relates to the field of nanofiber membrane materials technology, and in particular to a nanofiber membrane that combines waterproof, breathable, radiative cooling, and waterproof properties, its preparation method, and its applications. Background Technology

[0002] In recent years, there has been considerable research on using "atmospheric windows" to prepare materials with high infrared emission characteristics, and combining these with materials with high solar reflectivity to prepare radiative cooling materials. However, the application of these cooling materials is currently mainly concentrated in the industrial field. In the clothing industry, in addition to cooling properties, materials must also possess a certain level of comfort. There are specific requirements regarding the material's softness, breathability, and moisture permeability. Furthermore, for outdoor applications, waterproof performance is also essential.

[0003] Electrospinning is a cutting-edge technology for nanofiber preparation, enabling the large-scale production of nanofiber membranes with ultra-fine fiber diameters, controllable pore structures, and tunable wettability, thus opening the door to the manufacture of high-performance hydrophobic microporous membranes. While electrospinning can be used to prepare nanofiber membranes with radiative cooling properties, most fiber membranes have limitations in terms of wearing comfort, particularly in balancing waterproofness and breathability. Summary of the Invention

[0004] The purpose of this invention is to provide a nanofiber membrane that combines waterproof, breathable, and radiative cooling. This fiber membrane has the advantages of high elasticity, waterproofness, and breathability while cooling the temperature.

[0005] The technical solution adopted by this invention to solve its technical problem is:

[0006] A method for preparing a nanofiber membrane that combines waterproofing, breathability, and radiative cooling, comprising the following steps: S1, preparation of spinning solution:

[0007] Thermoplastic polyurethane (TPU) polymer was dissolved in a composite organic solvent. After stirring and dissolving, polydimethylsiloxane (PDMS) was added. Inorganic nanoparticles were added while stirring and dissolving to obtain a spinning solution.

[0008] The amount of PDMS added is 4%-16% based on the total weight of the polymer and the composite organic solvent as 100%.

[0009] The inorganic nanoparticles are one of silica particles and glass microspheres. The amount of inorganic nanoparticles added is 0.1-1.0% based on the total weight of the polymer and composite organic solvent as 100%.

[0010] S2. Preparation of nanofiber membranes:

[0011] The spinning solution of S1 was electrospun, and the nanofiber membrane was dried after spinning.

[0012] Preferably, the composite organic solvent is two or more of N,N-dimethylformamide, acetone, or tetrahydrofuran. More preferably, the mass ratio of N,N-dimethylformamide (DMF) to tetrahydrofuran (THF) in the composite organic solvent is 1:1.

[0013] Preferably, the electrospinning feed rate is 1.2 mL / h, the distance from the needle tip to the receiving roller is 12 cm, and the spinning voltage is 6-15 kV.

[0014] Preferably, the amount of PDMS added is 8%-12% based on the total weight of the polymer and the complex organic solvent (100%). The optimal value is 12%.

[0015] Preferably, the amount of inorganic nanoparticles added is 0.3-0.5%. The optimal value is 0.5%.

[0016] A nanofiber membrane prepared by the method described in this invention.

[0017] The present invention relates to the application of a nanofiber membrane that combines waterproof, breathable, and radiative cooling properties in cooling, high-elasticity, and waterproof fabrics.

[0018] This invention uses polyurethane (TPU) and polydimethylsiloxane (PDMS) as the base materials, and adds functional nanoparticles to synergistically improve the solar reflectivity and infrared emissivity of the materials. At the same time, the low surface energy of PDMS endows the fiber membrane with certain hydrophobic properties. Furthermore, the porous fiber membrane is manufactured by electrospinning, which makes the membrane breathable.

[0019] Electrospinning has the advantage of producing nanofiber membranes with a mesh structure, giving them a certain degree of breathability. This invention improves the water resistance of the fiber membrane while maintaining its breathability by adding a low surface energy compound to the spinning solution. The addition of functional nanoparticles synergistically enhances the infrared emission and water resistance of the fiber membrane at the "atmospheric window." These multiple functional additions allow the radiative cooling nanofiber membrane to be better applied in the textile industry. Attached Figure Description

[0020] Figure 1 Contact angle tests for Examples 1-4;

[0021] Figure 2 The air permeability tests for Examples 1-4;

[0022] Figure 3 For Examples 3, 5-8, solar reflectance and "atmospheric window emissivity" tests were conducted.

[0023] Figure 4 Characterization tests (SEM of nanofiber membrane surface (a) and fiber diameter distribution (b)) and scattering efficiency simulation (c) for Example 7;

[0024] Figure 5 The results show the reflectivity of the nanofiber membrane prepared in Example 7 in the solar radiation band and the emissivity in the mid-far-infrared band (a), and the comparison of outdoor cooling tests of Example 7 (TPU / PDMS / SiO2-0.5) with cotton fabric and air (b).

[0025] Figure 6 The stress-strain curve (a) and air permeability test results (b) of Example 7 are shown.

[0026] Figure 7 The results are the contact angle test results for Comparative Example 1(a) and Example 7(b). Detailed Implementation

[0027] The technical solution of the present invention will be further described in detail below through specific embodiments. It should be understood that the implementation of the present invention is not limited to the following embodiments, and any modifications and / or alterations made to the present invention will fall within the protection scope of the present invention.

[0028] In this invention, unless otherwise specified, all parts and percentages are by weight, and the equipment and raw materials used are commercially available or commonly used in the art. Unless otherwise specified, the methods in the following embodiments are conventional methods in the art.

[0029] Unless otherwise specified, the reagents used in the following examples can be purchased from a regular biochemical reagent store.

[0030] Example 1

[0031] A method for preparing a nanofiber membrane that combines waterproof, breathable, radiative cooling, and other properties, comprising the following specific steps:

[0032] Preparation of spinning solution: Weigh 2.5g of TPU particles and dissolve them in 7.5g of N,N-dimethylformamide (DMF) and tetrahydrofuran (THF) (the mass ratio of DMF to THF is 1:1, the same below). Stir for 12h. After complete dissolution, add 4% (based on the total weight of polymer and composite organic solvent as 100%) of PDMS and stir thoroughly to obtain the spinning solution.

[0033] Nanofiber membrane preparation: The prepared spinning solution was poured into a syringe for electrospinning. The spinning parameters were set as follows: voltage: 10 kV, receiving distance: 12 cm, spinning speed: 1.2 mL / h. After spinning for 6 h, the spun nanofiber membrane was removed and dried at 50 °C for 5 h. Subsequently, the obtained nanofiber membrane was characterized.

[0034] Example 2

[0035] Preparation of spinning solution: Weigh 2.5g of TPU particles and dissolve them in 7.5g of N,N-dimethylformamide (DMF) and tetrahydrofuran (THF). Stir for 12h and after complete dissolution, add 8% (based on the total weight of polymer and composite organic solvent as 100%) of PDMS and stir thoroughly to obtain the spinning solution.

[0036] Nanofiber membrane preparation: The prepared spinning solution was poured into a syringe for electrospinning. The spinning parameters were set as follows: voltage: 10 kV, receiving distance: 12 cm, spinning speed: 1.2 mL / h. After spinning for 6 h, the spun nanofiber membrane was removed and dried at 50 °C for 5 h. Subsequently, the obtained nanofiber membrane was characterized.

[0037] Example 3

[0038] Preparation of spinning solution: Weigh 2.5g of TPU particles and dissolve them in 7.5g of N,N-dimethylformamide (DMF) and tetrahydrofuran (THF). Stir for 12h and after complete dissolution, add 12% (based on the total weight of polymer and composite organic solvent as 100%) of PDMS and stir thoroughly to obtain the spinning solution.

[0039] Nanofiber membrane preparation: The prepared spinning solution was poured into a syringe for electrospinning. The spinning parameters were set as follows: voltage: 10 kV, receiving distance: 12 cm, spinning speed: 1.2 mL / h. After spinning for 6 h, the spun nanofiber membrane was removed and dried at 50 °C for 5 h. Subsequently, the obtained nanofiber membrane was characterized.

[0040] Example 4

[0041] Preparation of spinning solution: Weigh 2.5g of TPU particles and dissolve them in 7.5g of N,N-dimethylformamide (DMF) and tetrahydrofuran (THF). Stir for 12h and after complete dissolution, add 16% (based on the total weight of polymer and composite organic solvent as 100%) of PDMS and stir thoroughly to obtain the spinning solution.

[0042] Nanofiber membrane preparation: The prepared spinning solution was poured into a syringe for electrospinning. The spinning parameters were set as follows: voltage: 10 kV, receiving distance: 12 cm, spinning speed: 1.2 mL / h. After spinning for 6 h, the spun nanofiber membrane was removed and dried at 50 °C for 5 h. Subsequently, the obtained nanofiber membrane was characterized.

[0043] Example 5

[0044] Preparation of spinning solution: Weigh 2.5g of TPU particles and dissolve them in 7.5g of N,N-dimethylformamide (DMF) and tetrahydrofuran (THF). Stir for 12h until completely dissolved, then add 12% PDMS and continue stirring until completely dissolved. Finally, add 0.11% hydrophobic fumed silica (SiO2) and stir thoroughly to obtain the spinning solution.

[0045] Nanofiber membrane preparation: The prepared spinning solution was poured into a syringe for electrospinning. The spinning parameters were set as follows: voltage: 10 kV, receiving distance: 12 cm, spinning speed: 1.2 mL / h. After spinning for 6 h, the spun nanofiber membrane was removed and dried at 50 °C for 5 h. Subsequently, the obtained nanofiber membrane was characterized.

[0046] Example 6

[0047] Preparation of spinning solution: Weigh 2.5g of TPU particles and dissolve them in 7.5g of N,N-dimethylformamide (DMF) and tetrahydrofuran (THF). Stir for 12h until completely dissolved, then add 12% PDMS and continue stirring until completely dissolved. Finally, add 0.3% hydrophobic fumed silica (SiO2) and stir thoroughly to obtain the spinning solution.

[0048] Nanofiber membrane preparation: The prepared spinning solution was poured into a syringe for electrospinning. The spinning parameters were set as follows: voltage: 10 kV, receiving distance: 12 cm, spinning speed: 1.2 mL / h. After spinning for 6 h, the spun nanofiber membrane was removed and dried at 50 °C for 5 h. Subsequently, the obtained nanofiber membrane was characterized.

[0049] Example 7

[0050] Preparation of spinning solution: Weigh 2.5g of TPU particles and dissolve them in 7.5g of N,N-dimethylformamide (DMF) and tetrahydrofuran (THF). Stir for 12h until completely dissolved. Then add 12% PDMS and continue stirring until completely dissolved. Finally, add 0.55% hydrophobic fumed silica (SiO2) and stir thoroughly to obtain the spinning solution.

[0051] Nanofiber membrane preparation: The prepared spinning solution was poured into a syringe for electrospinning. The spinning parameters were set as follows: voltage: 10 kV, receiving distance: 12 cm, spinning speed: 1.2 mL / h. After spinning for 6 h, the spun nanofiber membrane was removed and dried at 50 °C for 5 h. Subsequently, the obtained nanofiber membrane was characterized.

[0052] Example 8

[0053] Preparation of spinning solution: Weigh 2.5g of TPU particles and dissolve them in 7.5g of N,N-dimethylformamide (DMF) and tetrahydrofuran (THF). Stir for 12h until completely dissolved. Then add 12% PDMS and continue stirring until completely dissolved. Finally, add 0.8% hydrophobic fumed silica (SiO2) and stir thoroughly to obtain the spinning solution.

[0054] Nanofiber membrane preparation: The prepared spinning solution was poured into a syringe for electrospinning. The spinning parameters were set as follows: voltage: 10 kV, receiving distance: 12 cm, spinning speed: 1.2 mL / h. After spinning for 6 h, the spun nanofiber membrane was removed and dried at 50 °C for 5 h. Subsequently, the obtained nanofiber membrane was characterized.

[0055] Comparative Example 1

[0056] 2.5g of TPU particles were weighed and dissolved in 7.5g of N,N-dimethylformamide (DMF) and tetrahydrofuran (THF). The mixture was stirred for 12 hours until completely dissolved, and then electrospun. The spinning parameters were set as follows: 12kV, receiving distance: 12cm, and spinning speed: 1.2mL / h. After spinning for 6 hours, the spun nanofiber membrane was removed and dried at 50℃ for 5 hours.

[0057] Various tests were performed on the nanofiber membranes prepared in Examples 1-8 and Comparative Example 1.

[0058] Figure 1 , Figure 2 Contact angle and breathability tests were conducted on different dosages of polydimethylsiloxane (Examples 1-4). As the dosage increased, the waterproof performance of the nanofiber membrane improved, but the breathability decreased. To balance breathability and waterproof performance, a dosage of 12% was deemed most suitable.

[0059] Figure 3To investigate the solar reflectance and "atmospheric window" emissivity of different amounts of silica (Examples 4-8), when the silica content was 0%, the solar reflectance of the film reached 91%, while the emissivity was only 84.3%. When the content exceeded 0.5%, the reflectance and emissivity of the film decreased to some extent. This is because when too much fumed silica is added, the viscosity of the spinning solution becomes too high, the structure of the film changes, more fibers adhere together, and the number of nanopores decreases. The refractive difference between the polymer and the pores becomes smaller. Therefore, a silica content of 0.5% is most suitable.

[0060] SEM images of the nanofiber membrane surface (a) and fiber diameter distribution (b) are shown below. Figure 4 As shown; the TPU / PDMS / SiO2 nanofibers have a uniform diameter, distributed at approximately 1.2 μm. Figure 4 (C) shows the simulation of the scattering efficiency of TPU / PDMS / SiO2 nanofiber membrane in the solar band. The fibers with a diameter of about 1.2 μm have good scattering efficiency, thereby enhancing the solar reflectivity of the nanofiber membrane.

[0061] The reflectance in the solar band and the emissivity in the mid-to-far-infrared band of the nanofiber membrane prepared in Example 7 are compared with those of Example 7 (TPU / PDMS / SiO2) in outdoor cooling tests with cotton fabric and air (b). Figure 5 As shown, the nanofiber membrane has a solar reflectivity of up to 95.6% and an infrared emissivity of up to 93.2% in the "atmospheric window." In actual outdoor cooling tests, compared with cotton fabric, the prepared nanofiber membrane can achieve a cooling effect of up to 10°C. It has excellent cooling performance.

[0062] Figure 6 (a) shows the stress-strain curves of Comparative Example 1 and Example 7. Although the elongation at break of the TPU / PDMS / SiO2 nanofiber membrane decreased, it still reached about 380%, and the tensile strength was significantly improved. Figure 6 (b) shows the air permeability test of Example 7. Under a pressure of 100 MPa, the air permeability of the TPU / PDMS / SiO2 nanofiber membrane reached more than 10 mm / s, indicating that it has certain air permeability performance.

[0063] The contact angle test results of Comparative Example 1(a) and Example 7(b) are as follows: Figure 7 As shown. Compared with TPU nanofiber membranes, TPU / PDMS / SiO2 nanofiber membranes have superior waterproof performance.

[0064] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to in the method section.

[0065] The present invention has provided a detailed description of the waterproof, breathable, radiative cooling nanofiber membrane, its preparation method, and its applications. Specific examples have been used to illustrate the principles and implementation methods of the invention. These examples are merely illustrative and are intended to aid in understanding the method and core concepts of the invention. It should be noted that those skilled in the art can make various improvements and modifications to the invention without departing from its principles, and these improvements and modifications also fall within the scope of protection of the claims.

Claims

1. A method for preparing a nanofiber membrane that combines waterproof, breathable, radiative cooling, characterized in that... The method includes the following steps: S1. Preparation of spinning solution: Thermoplastic polyurethane (TPU) polymer was dissolved in a composite organic solvent, and after stirring and dissolving, polydimethylsiloxane (PDMS) was added. Inorganic nanoparticles were added while stirring and dissolving to obtain a spinning solution. The amount of PDMS added is 8%-12% based on the total weight of the polymer and the composite organic solvent as 100%. The inorganic nanoparticles are hydrophobic fumed silica particles, and the amount of inorganic nanoparticles added is 0.3-0.5% based on the total weight of the polymer and composite organic solvent as 100%. The mass ratio of TPU polymer to composite organic solvent is 1:3; S2. Preparation of nanofiber membranes: The spinning solution of S1 was electrospun at a feed rate of 1.2 mL / h, a distance of 12 cm from the needle tip to the receiving roller, and a spinning voltage of 6-15 kV. After spinning, the nanofiber membrane was dried at 50°C for 5 h. The composite organic solvent is N,N-dimethylformamide and tetrahydrofuran, with a mass ratio of 1:1 between N,N-dimethylformamide (DMF) and tetrahydrofuran (THF).

2. A nanofiber membrane prepared by the preparation method according to claim 1.

3. The application of a nanofiber membrane with waterproof, breathable, and radiative cooling properties as described in claim 2 in the field of cooling, high-elasticity, and waterproof fabrics.

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