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CN-121992577-A - Breathable nanofiber membrane with waterproof and intelligent thermal management functions and preparation method

CN121992577ACN 121992577 ACN121992577 ACN 121992577ACN-121992577-A

Abstract

The invention discloses a breathable nanofiber membrane with waterproof and intelligent thermal management functions and a preparation method thereof, and belongs to the technical field of functional nanofiber membrane preparation. The nanofiber membrane comprises a first fiber layer, a second fiber layer and a second fiber layer, wherein the first fiber layer comprises liquid crystal elastomer fibers, liquid crystal elements of the liquid crystal elastomer fibers are oriented along a first direction, fiber shafts of the second fiber layer comprise thermoplastic polyurethane fibers, the fiber shafts of the thermoplastic polyurethane fibers are oriented along a second direction, the two layers of fibers are compounded through hot-pressing crosslinking, and the first direction is intersected with the second direction. The invention uses the temperature response of the liquid crystal elastomer, the fiber layer contracts along the orientation direction at the height Wen Shidi, the aperture of the driving membrane is increased due to the restraint and the orthogonal arrangement of the second fiber layer, the air permeability is obviously improved, and the original state is restored at low temperature. The film has excellent waterproof performance (water pressure resistance is more than 40 kPa) and intelligent thermal management function (ventilation can be reversibly regulated between 9.6 and 55 mm/s), and has wide application prospects in the fields of functional clothing, intelligent wearing and the like.

Inventors

  • LU CHUN
  • XU BAOJIAN
  • LIU WENJUAN
  • LUO YONGJIAN

Assignees

  • 湖南中科纳威新材料有限公司

Dates

Publication Date
20260508
Application Date
20260407

Claims (10)

  1. 1. Breathable nanofiber membrane with waterproof and intelligent thermal management, characterized by comprising: A first fibrous layer comprising liquid crystal elastomer fibers having liquid crystal cells oriented in a first direction, and comprising silicone segments in a crosslinked network of the liquid crystal elastomer fibers; a second fibrous layer comprising thermoplastic polyurethane fibers having fiber axes oriented in a second direction; The first fiber layer and the second fiber layer are compounded through hot pressing crosslinking, and the first direction and the second direction are intersected.
  2. 2. The nanofiber membrane according to claim 1, wherein in the liquid crystal elastomer fiber, the liquid crystal cells are connected through a siloxane segment and form a crosslinked network, and the thermoplastic polyurethane fiber comprises polyurethane with NCO content of 1% -10%, preferably polyether polyurethane or polyester polyurethane.
  3. 3. The nanofiber membrane according to claim 1, characterized in that the angle between the first direction and the second direction is 80 ° to 100 °, preferably 90 °.
  4. 4. The nanofiber membrane of claim 1, wherein the nanofiber membrane has a temperature-responsive breathable function, when the ambient temperature rises from room temperature to the bright point of the liquid crystal elastomer, the liquid crystal elastomer fibers in the first fiber layer shrink in a first direction to drive the pore diameter of the nanofiber membrane to increase, when the ambient temperature decreases and is far away from the bright point of the liquid crystal elastomer, the liquid crystal elastomer fibers return to a long length, the pore diameter of the nanofiber membrane returns, and the bright point temperature of the liquid crystal elastomer is 55-62 ℃.
  5. 5. A method of preparing the nanofiber membrane of any one of claims 1 to 4, comprising the steps of: s1, providing a first spinning solution, wherein the first spinning solution comprises a liquid crystal monomer, hydrogen-containing siloxane and first polyurethane; S2, providing a second spinning solution, wherein the second spinning solution comprises second polyurethane; s3, carrying out electrostatic spinning on the first spinning solution, and collecting to obtain a first nanofiber membrane with a first orientation direction; S4, carrying out electrostatic spinning on the second spinning solution, and collecting to obtain a second nanofiber membrane with a second orientation direction; S5, carrying out hot-pressing treatment on the first nanofiber membrane and the second nanofiber membrane to enable the first nanofiber membrane and the second nanofiber membrane to be compounded, and carrying out a crosslinking reaction to obtain the nanofiber membrane; In step S5, the first orientation direction of the first nanofiber membrane and the second orientation direction of the second nanofiber membrane form a preset included angle.
  6. 6. The method according to claim 5, wherein the step S1 specifically comprises the steps of reacting the liquid crystal monomer, the hydrogen-containing siloxane and the catalyst in a solvent to obtain a reaction product, adding the first polyurethane into the reaction product, and uniformly mixing to obtain the first spinning solution; Preferably, the liquid crystal monomer is selected from one or more of 2-methyl-1, 4-phenyl 4- (3-acryloxypropoxy) benzoate, 4- (4-cyanobiphenyl-4' -yloxy) alkyl acrylate and 4-allyloxybenzoic acid p-cyanobenzene ester; Preferably, the hydrogen-containing siloxane is selected from one or more of single-end dihydroxyl hydrogen-containing siloxane, double-end monohydroxy hydrogen-containing siloxane, single-end diamino hydrogen-containing siloxane, double-end monoamino hydrogen-containing siloxane and single-end monoamino hydrogen-containing siloxane; preferably, the catalyst is potassium tert-butoxide or N-heterocyclic carbene; preferably, the mass ratio of the liquid crystal monomer to the hydrogen-containing siloxane is 0.1-50.
  7. 7. The method according to claim 5, wherein in step S3, the rotational speed of the electrospinning drum is 2500 to 6000 rpm to obtain the first nanofiber membrane having an oriented structure; In the step S4, the rotating speed of the electrostatic spinning roller is 1500-6000 rpm, so as to obtain the second nanofiber membrane with the orientation structure.
  8. 8. The method according to claim 5, wherein in step S5, the heat pressing is performed at a temperature of 60 ℃ to 135 ℃, a pressure of 0.05 MPa to 0.5 MPa, and a time of 0.5 min to 5 min.
  9. 9. The method according to claim 5, wherein the predetermined angle is 80 ° to 100 °, preferably 90 °.
  10. 10. Use of the nanofiber membrane of any one of claims 1 to 4 or the nanofiber membrane prepared by the method of any one of claims 5 to 9 in the preparation of functional garments, smart wear devices, smart packaging materials, gas separation membranes or battery separators.

Description

Breathable nanofiber membrane with waterproof and intelligent thermal management functions and preparation method Technical Field The invention belongs to the technical field of functional nanofiber membrane preparation, and particularly relates to a breathable nanofiber membrane with waterproof and intelligent thermal management functions and a preparation method thereof. Background Along with the rapid development of outdoor exercises and intelligent wearing industries, the demands of markets for high-performance functional textile fabrics continuously rise, and particularly, intelligent protection materials with waterproof, moisture-permeable and sweat-releasing functions and self-adaptive temperature regulation and control functions become the core direction of industry research and development. The waterproof moisture-permeable membrane is used as a core layer of the functional garment, the barrier of external liquid water and the discharge of human sweat and water vapor are required to be realized at the same time, the traditional waterproof moisture-permeable membrane adopts a fixed micropore structure or a hydrophilic polymer system, passive moisture permeability can be realized only, intelligent regulation and control cannot be realized according to human activity and environmental temperature change, and natural contradiction exists between wearing comfort and protection performance due to the fact that the moisture-permeable sweat-discharging requirement under high-temperature high-movement strength and the heat-insulating requirement under low-temperature environment are difficult to be considered. At present, the main stream of waterproof and moisture permeable materials mainly comprises two main types, namely microporous membranes based on Polytetrafluoroethylene (PTFE), and waterproof and moisture permeable materials are realized by utilizing the principle that the pore diameter of the microporous membranes is smaller than that of water drops but larger than that of water vapor molecules. However, such films are susceptible to clogging of micropores by greasy dirt, sweat contamination, resulting in reduced moisture permeability, and the PTFE material itself is difficult to degrade, presenting an environmental risk (as shown in patent CN115323622a, the inherent drawbacks of PTFE remain, although the blending of TPU with PTFE is improved by the addition of modifiers). The other is a hydrophilic non-porous film based on Thermoplastic Polyurethane (TPU) that adsorbs and conducts water molecules through hydrophilic groups on its molecular chain. However, the moisture permeability of the film is greatly affected by environmental humidity, the driving force is reduced under the high-humidity environment, the moisture permeability efficiency is limited, and the waterproof performance and the moisture permeability often have contradictory relationship with each other (as shown in patent CN114855361A, the thermal regulation is realized by adding a fatty acid phase change material, but the moisture permeability mechanism still depends on the traditional hydrophilic conduction, and the performance improvement is limited). To further enhance the smart responsiveness of materials, researchers have attempted to introduce temperature responsive materials. For example, patent CN112160072a discloses a sheath-core phase-change temperature-regulating fiber film prepared by coaxial electrostatic spinning, which utilizes the heat storage property of the phase-change material to realize passive temperature regulation. However, the technology mainly relies on the self heat capacity of the material to buffer temperature change, but does not actively regulate the breathing function of the membrane structure, the moisture permeability of the technology depends on the intrinsic characteristics of the shell material, and dynamic and large-amplitude regulation and control of the air permeability are difficult to realize. The prior art has not provided an intelligent material capable of actively and reversibly adjusting a self-microporous structure through temperature change, thereby realizing remarkable dynamic change of air permeability while maintaining excellent water resistance. How to solve the contradiction between the waterproof property and the high moisture permeability and to enable the air permeability of the material to be regulated and controlled automatically according to the temperature requirement is a technical problem to be solved in the field. Disclosure of Invention The invention aims to overcome the defects of the prior art, and provides a nanofiber membrane with waterproof and intelligent thermal management functions and a preparation method thereof, so as to realize dynamic regulation and control of temperature responsiveness of material air permeability and simultaneously endow the material with excellent waterproof performance. In order to achieve the above purpose, the present invention provides