Automatic humidity control functional fiber film based on intelligent temperature sensing and method for manufacturing the same

Abstract

The application provides an automatic humidity adjusting type functional fiber membrane based on intelligent temperature sensing and a preparation method thereof. The method is to construct a new type of instantaneous free radical integrated polymerization gel composite fiber layer on the surface of the padding finished intelligent temperature sensing fiber membrane, and the two are organically combined to form a "double intelligent response system" functional fiber membrane finished product. Overall, the intelligent response characteristics of wash-resistant, wear-resistant, low temperature moisture absorption and high temperature one-way moisture transfer are realized, so that the raw fiber becomes a functional intelligent fiber fabric with excellent moisture permeability, air permeability, wear resistance and other multiple protection functions, and can realize wash-resistant ability and ultra-light design.

Description

Technical Field

[0001] This invention relates to functional fiber materials and their preparation methods, specifically to flexible nanofiber materials with intelligent temperature sensing and unidirectional moisture-wicking properties, and their preparation methods. Background Technology

[0002] Intelligent flexible materials refer to flexible fiber functional materials that integrate sensing, feedback, and response. They can perceive external changes in a timely, dynamic, and precise manner, mimicking certain functions of a living system. These materials are widely used in industries such as smart wearables, energy conservation and environmental protection, information technology, and biomedical materials, with particularly great application potential in apparel, medical, and military fields. Currently, various temperature-sensing fibers, or simply temperature-sensitive fibers, have emerged. These are textile materials that incorporate intelligent sensing polymers into the spinning solution, enabling precise response and control of wetting properties based on temperature changes, thus endowing the fiber materials with intelligent temperature-sensing response properties. For example:

[0003] Patent document CN 110512305A discloses an antibacterial temperature-controlled nanofiber and its preparation method. The method involves introducing an N-isopropylacrylamide temperature-sensitive polymer into a modified sericin solution to prepare a hydrogel, and then obtaining nanofibers with temperature-controlled properties through electrospinning.

[0004] Patent document CN 110528112 A discloses an antibacterial temperature-controlled micro / nanofiber and its preparation method, which involves introducing N-isopropylacrylamide into polyethylene oxide to prepare a spinning solution, and then preparing temperature-controlled nanofibers by microfluidic spinning.

[0005] Another patent document, CN 106758235 B, discloses a thermosensitive antibacterial fabric and its preparation method. It designs a chitosan / polyN-isopropylacrylamide spinning solution and also prepares fibers with both antibacterial and thermosensitive properties through microfluidic spinning.

[0006] Existing electrospinning or microfluidic spinning processes generally suffer from the technical drawback of demanding stringent fiber formation conditions. Because the preparation processes described in the literature require the spinning solution to be jetted into fibers under the action of an electrostatic field or tensile force, it is necessary to use excessive amounts of fiber-forming polymers, such as sericin and polyethylene oxide, as carriers of the spinning solution to overcome the technical problems of inability to spin or form fibers. However, this prevents the intelligent sensing component from being added arbitrarily as needed. Due to the low amount of intelligent temperature-sensing polymer added, the sensing response often fails to reach the required level. Furthermore, in the spinning technologies described above, the intelligent polymer is simply mixed directly with the fiber-forming polymer as an additive. This excessive exposure of the intelligent polymer in the spun fibers leads to rapid leakage during use, resulting in finished fibers that are not washable or abrasion-resistant, and whose intelligent response is not durable.

[0007] Existing technologies reveal that the development of multi-performance combinations in temperature-sensitive fibers is currently very limited. Most studies have only demonstrated that fibers exhibit different wettability at different temperatures. Furthermore, the variety of temperature-sensitive polymers and their varying properties mean that no substantial research has been conducted on which polymer's temperature control range significantly impacts its application in comfortable and protective clothing textiles. More importantly, current research adds antibacterial chitosan to temperature-controlled polymers to enhance antibacterial properties, but has not achieved breakthroughs in other technical performance areas, particularly in the more pressing need for unidirectional moisture wicking to achieve comfort control in clothing. On the other hand, current unidirectional moisture-wicking fiber products also suffer from the technical problem of limited functionality. Moreover, the reality is that temperature sensing and humidity guidance are being developed independently, and many, including researchers, consider them two unrelated technological development paths. The method for preparing intelligent one-way moisture-wicking fabric in patent document CN115071232A adopts a composite method of hydrophilic layer and hydrophobic layer. The hydrophilic layer is spun from hydrophilic fibers, and the hydrophobic layer is made by winding and twisting blended fibers and hydrophobic fibers. This composite fiber fabric has only a single one-way moisture-wicking property.

[0008] The fiber-based waterproof and breathable membrane with intelligent one-way moisture-wicking function disclosed in patent document CN 105966006A uses one or more of sodium polyacrylate, polyacrylamide and polyvinyl alcohol to prepare a hydrophilic fiber layer by electrospinning. Then, a polyvinyl butyral adhesive layer is spun onto the surface of the hydrophilic layer by spraying, followed by a hydrophobic layer being spun onto the surface of the adhesive layer. Finally, it is heat-treated to form the three-layer composite membrane. Under low humidity conditions, it opens the pores to conduct steam, and under high humidity conditions, it closes the pores to conduct sweat. However, it does not have the ability to intelligently regulate the temperature and humidity and guide liquid. Summary of the Invention

[0009] The purpose of this patent application is to solve the problem of how to endow fiber membrane products with intelligent control combination and synergistic conversion characteristics of temperature sensing and moisture guiding, so as to realize the intelligent conversion of low temperature moisture absorption and high temperature unidirectional moisture guiding, while solving the technical problem of poor intelligent response durability due to poor washability and abrasion resistance. The invention provides an automatic moisture regulating functional fiber membrane based on intelligent temperature sensing and its preparation method.

[0010] The main technical content of the intelligent temperature-sensing automatic humidity-regulating functional fiber membrane technology solution provided in this patent application is: an intelligent temperature-sensing automatic humidity-regulating functional fiber membrane, which is prepared by the following process steps:

[0011] Step 1). Preparation of temperature-sensitive fiber membrane

[0012] a. Preparation of finishing agent

[0013] Add cage-type polysilsesquioxane to a poly(N-isopropylacrylamide) N,N-dimethylformamide solution, mix thoroughly, then add low-temperature unblocking isocyanate and 2-ethyl-4-methylimidazole, mix thoroughly, and obtain finishing agent;

[0014] The N,N-dimethylformamide solution of poly(N-isopropylacrylamide) comprises, by weight, the following:

[0015] 70-80 parts of N,N-dimethylformamide

[0016] 20-30 parts of poly-N-isopropylacrylamide;

[0017] Based on per 100 parts by weight of the solution, the cage-type polysilsesquioxane comprises 0.5-1 parts.

[0018] The low-temperature unblocking type of isocyanate is 0.5-1 part.

[0019] 0.05-0.1 parts of 2-ethyl-4-methylimidazole;

[0020] b. Processing to obtain temperature-sensitive fiber membrane

[0021] At room temperature, a polyacrylonitrile fiber membrane is immersed in a finishing agent, subjected to two dips and two rolls, and then baked at 60-80℃ to obtain a smart temperature-sensing fiber membrane.

[0022] Step 2). Preparation of the finished fiber membrane

[0023] a. Preparation of spinning solution

[0024] At room temperature and under a nitrogen atmosphere, N,N-methylenebisacrylamide and ammonium persulfate were added to an aqueous solution of N-isopropylacrylamide and mixed thoroughly. Then, low-temperature unblocking isocyanate was added and mixed thoroughly. Finally, sodium alginate was added to obtain the fiber core spinning solution.

[0025] The mass concentration of the N-isopropylacrylamide aqueous solution is 3-7%;

[0026] Based on the aforementioned aqueous solution per 100 parts by weight:

[0027]

[0028] b. Production of fiber membrane finished products

[0029] The spinning solution is the fiber core, and a 500mM calcium chloride solution is introduced into the sheath layer. Microfluidic spinning is performed on the surface of the intelligent temperature-sensing fiber membrane obtained in step 1) to form a gel fiber layer with a core-sheath structure, thus obtaining the finished functional fiber membrane.

[0030] One preferred embodiment of the above overall technical solution is microfluidic spinning at a temperature of 20-30℃, a spinning rate of 30-50 rad / min, and a flow rate of 20-30 uL / s.

[0031] This patent application also provides a method for preparing the above-mentioned intelligent temperature-sensing automatic humidity-regulating functional fiber membrane.

[0032] In this patent application, poly(N-isopropylacrylamide) serves as the first intelligent temperature control "response switch." Through low-temperature unsealing and double crosslinking of the blocked isocyanate and 2-ethyl-4-methylimidazolium, it is locked within the "cage" molecular structure of the cage-like polysilsesquioxane. An interpenetrating network (IPN) double crosslinking anchoring structure is constructed on the flexible skeleton of the polyacrylonitrile fiber membrane, effectively encapsulating the poly(N-isopropylacrylamide) within the IPN three-dimensional network structure. This solves the technical problem of functional polymer leakage and achieves wash resistance. Secondly, N,N-dimethylformamide solvent is selected. In addition, N,N-dimethylformamide forms micropores in the IPN structure to achieve rapid and intelligent humidity control, avoiding the blockage of fiber pore channels on the surface of the fiber membrane due to the polymer finishing layer, thus improving the moisture permeability and air permeability of the fiber membrane. While achieving durable intelligent temperature-sensing response, it also creates conditions for rapid water vapor transport. Thirdly, the low-temperature unsealing isocyanate also gives the finishing layer wear resistance and replaces the existing high-temperature baking method with a low-energy, low-temperature process mode, overcoming the technical problem of fiber membrane hardening due to high-temperature baking and maintaining the original flexibility of the fiber.

[0033] Using the treated temperature-sensitive fiber membrane as a substrate, a "skin-core" structured gel fiber layer with microfluidic free radical integral polymerization is formed on its surface. N,N-methylenebisacrylamide and low-temperature unblocking isocyanate are double-crosslinked with N-isopropylacrylamide NIPAM smart polymer, forming a double-crosslinked anchored core layer that constitutes the second layer of smart "temperature control response switch" in free radical polymerization. The smart polymer is sealed through a three-dimensional crosslinking network, and the calcium chloride in the sheath layer and the sodium alginate in the core layer undergo instantaneous free radical polymerization in microfluidic spinning to form an inner and outer coating gel. The crosslinked anchored smart polymer is coated in the core layer, further preventing smart polymer leakage and achieving high efficiency, washability, and durability.

[0034] In this invention patent solution, the microfluidic fiber is integrally formed by free radical molding and manufactured into a single spinning process. The process is simple, and because the sodium alginate molecular chain is extended and contains a large number of hydroxyl structural groups, its hydrophilic groups are continuously dissociated during the spinning process, which makes the microfluidic fiber membrane exhibit hydrophilic and moisture-absorbing properties.

[0035] The finishing layer designed in this application contains both hydrophilic amide groups and hydrophobic isopropyl groups in its poly(N-isopropylacrylamide) polymer structure. The polymer exhibits two modes of volume change near the low critical temperature (LCST): swelling and shrinkage. This application utilizes the hydrogen bonding between the hydrophilic groups and surrounding water molecules, and the hydrophobic association between the hydrophobic groups, to induce a change in wettability, giving the final product intelligent wettability regulation: At an LCST ambient temperature below 38°C, the hydrogen bonds between the amide groups of the poly(N-isopropylacrylamide) and water molecules in the finished polyacrylonitrile fiber membrane neutralize the hydrophobic interactions between the isopropyl groups, allowing the molecular chains to swell and expand fully under the influence of surrounding moisture. At this point, the functional fiber membrane exhibits hydrophilic wettability. Simultaneously, combined with the sodium alginate gel microfluidic composite fiber layer, the overall structure exhibits dual hydrophilic and hygroscopic properties. At ambient temperatures exceeding 38°C... At this time, the hydrogen bonding force between the hydrophilic amide groups of poly(N-isopropylacrylamide) and water molecules is significantly reduced, while the hydrophobic association between isopropyl groups is enhanced. The treated polyacrylonitrile fiber membrane exhibits hydrophobicity. It forms a Janus composite system with different wettability with the sodium alginate hydrophilic gel composite fiber membrane layer, forming a wetting gradient and differential capillary effect. The two work together, and under the "push-pull" action of droplet gravity, Yang-Laplace force and capillary pull, it enters the droplet unidirectional moisture-wicking mode, which can complete the function of rapid evaporation of sweat. Especially as a medical, military or sports protective clothing fabric, it can automatically switch to a liquid-oriented unidirectional moisture-wicking process when the external ambient temperature exceeds 38°C, and quickly expel body sweat. It achieves the technical purpose of automatic temperature sensing and regulation of wetting performance, which greatly improves the intelligent regulation and wearing comfort of this functional fiber membrane.

[0036] In summary, this technical solution constructs a novel instantaneous free radical integrated polymer gel composite fiber layer on the surface of the impregnated intelligent temperature-sensing fiber membrane. The organic combination of the two constitutes a functional fiber membrane product with a "dual intelligent response system". Its microstructure encapsulates and cross-links the intelligent polymer. While maintaining the original flexibility of the fiber membrane, its microchannels and micropores create conditions for the construction of organic regulation of the dual-layer wetting gradient after intelligent temperature sensing and the effective performance. The finished functional fiber membrane product generally achieves intelligent response characteristics such as washability, abrasion resistance, low-temperature moisture absorption, and high-temperature unidirectional moisture conduction. This makes the raw fiber a functional intelligent fiber fabric with multiple protective functions such as excellent moisture permeability, air permeability, and abrasion resistance, and can achieve washability and ultra-light design. Detailed Implementation

[0037] The following examples will further illustrate the technical content of the intelligent temperature-sensing automatic humidity-regulating functional fiber membrane and its preparation method based on this patent application, and explain its application effects.

[0038] Example 1

[0039] 1) Preparation of temperature-sensitive fiber membrane

[0040] a. Preparation of finishing agent

[0041] Preparation of N,N-dimethylformamide solution of poly-N-isopropylacrylamide: by weight, 20 parts of poly-N-isopropylacrylamide and 80 parts of N,N-dimethylformamide are stirred for 30 min;

[0042] Add 0.5 parts of cage-type polysilsesquioxane to a poly(N-isopropylacrylamide) N,N-dimethylformamide solution and stir for 30 min. Then add 0.5 parts of low-temperature unblocking isocyanate and 0.05 parts of 2-ethyl-4-methylimidazole and stir for 30 min to obtain the finishing agent.

[0043] b. Processing to obtain temperature-sensitive fiber membrane

[0044] At room temperature, the polyacrylonitrile fiber membrane is immersed in the finishing agent, subjected to two dips and two rolls, and then baked at 60°C for 3 minutes to obtain the polyacrylonitrile intelligent temperature-sensing fiber membrane.

[0045] Step 2). Preparation of the finished fiber membrane

[0046] a. Preparation of spinning solution

[0047] At room temperature and under nitrogen protection, 3 parts by weight of N-isopropylacrylamide were added to 97 parts by weight to prepare an aqueous solution of N-isopropylacrylamide. The solution was stirred for 30 min, then 0.2 parts of N,N-methylenebisacrylamide and 0.2 parts of ammonium persulfate were added and stirred for 30 min. Then 0.5 parts of low-temperature unblocking isocyanate were added and stirred for another 30 min. Finally, 4 parts of sodium alginate were added to prepare the fiber core spinning solution.

[0048] b. Production of fiber membrane finished products

[0049] The spinning solution is the fiber core, and a 500mM calcium chloride solution is introduced into the sheath layer. Microfluidic spinning is performed on the surface of the polyacrylonitrile intelligent temperature-sensing fiber membrane obtained in step 1) to form a gel fiber layer with a core-sheath structure, thus obtaining the finished fiber membrane. The microfluidic spinning temperature is 20℃, the spinning rate is 30rad / min, and the flow rate is 20uL / s.

[0050] Example 2

[0051] 1) Preparation of temperature-sensitive fiber membrane

[0052] a. Preparation of finishing agent

[0053] Preparation of N,N-dimethylformamide solution of poly-N-isopropylacrylamide: by weight, 23 parts of poly-N-isopropylacrylamide and 77 parts of N,N-dimethylformamide are stirred for 30 min;

[0054] Add 0.6 parts of cage-type polysilsesquioxane to a poly(N-isopropylacrylamide) N,N-dimethylformamide solution and stir for 30 min. Then add 0.6 parts of low-temperature unblocking isocyanate and 0.06 parts of 2-ethyl-4-methylimidazole and stir for 30 min to obtain the finishing agent.

[0055] b. Processing to obtain temperature-sensitive fiber membrane

[0056] At room temperature, the polyacrylonitrile fiber membrane is immersed in the finishing agent, subjected to two dips and two rolls, and then baked at 65°C for 3 minutes to obtain the polyacrylonitrile intelligent temperature-sensing fiber membrane.

[0057] Step 2). Preparation of the finished fiber membrane

[0058] a. Preparation of spinning solution

[0059] At room temperature and under nitrogen protection, 4 parts by weight of N-isopropylacrylamide were added to 96 parts by weight to prepare an aqueous solution of N-isopropylacrylamide. The solution was stirred for 30 min, then 0.25 parts of N,N-methylenebisacrylamide and 0.25 parts of ammonium persulfate were added and stirred for 30 min. Subsequently, 0.6 parts of low-temperature unblocking isocyanate were added and the solution was stirred for another 30 min. Finally, 4.5 parts of sodium alginate were added to prepare the fiber core spinning solution.

[0060] b. Production of fiber membrane finished products

[0061] The spinning solution is the fiber core, and a 500mM calcium chloride solution is introduced into the sheath layer. Microfluidic spinning is performed on the surface of the polyacrylonitrile intelligent temperature-sensing fiber membrane obtained in step 1) to form a gel fiber layer with a core-sheath structure, thus obtaining the finished fiber membrane. The microfluidic spinning temperature is 22℃, the spinning rate is 33rad / min, and the flow rate is 22uL / s.

[0062] Example 3

[0063] 1) Preparation of temperature-sensitive fiber membrane

[0064] a. Preparation of finishing agent

[0065] Preparation of N,N-dimethylformamide solution of poly-N-isopropylacrylamide: by weight, 26 parts of poly-N-isopropylacrylamide and 74 parts of N,N-dimethylformamide are stirred for 30 min;

[0066] Add 0.7 parts of cage-type polysilsesquioxane to a poly(N-isopropylacrylamide) N,N-dimethylformamide solution and stir for 30 min. Then add 0.7 parts of low-temperature unblocking isocyanate and 0.07 parts of 2-ethyl-4-methylimidazole and stir for 30 min to obtain the finishing agent.

[0067] b. Processing to obtain temperature-sensitive fiber membrane

[0068] At room temperature, the polyacrylonitrile fiber membrane is immersed in the finishing agent, subjected to two dips and two rolls, and then baked at 70°C for 3 minutes to obtain the polyacrylonitrile intelligent temperature-sensing fiber membrane.

[0069] Step 2). Preparation of the finished fiber membrane

[0070] a. Preparation of spinning solution

[0071] At room temperature and under nitrogen protection, 5 parts by weight of N-isopropylacrylamide were added to 95 parts by weight to prepare an aqueous solution of N-isopropylacrylamide. The solution was stirred for 30 min, then 0.3 parts of N,N-methylenebisacrylamide and 0.3 parts of ammonium persulfate were added and stirred for 30 min. Then 0.7 parts of low-temperature unblocking isocyanate were added and stirred for another 30 min. Finally, 5 parts of sodium alginate were added to prepare the fiber core spinning solution.

[0072] b. Production of fiber membrane finished products

[0073] The spinning solution is the fiber core, and a 500mM calcium chloride solution is introduced into the sheath layer. Microfluidic spinning is performed on the surface of the polyacrylonitrile intelligent temperature-sensing fiber membrane obtained in step 1) to form a gel fiber layer with a core-sheath structure, thus obtaining the finished fiber membrane. The microfluidic spinning temperature is 23℃, the spinning rate is 40rad / min, and the flow rate is 25uL / s.

[0074] Example 4

[0075] 1) Preparation of temperature-sensitive fiber membrane

[0076] a. Preparation of finishing agent

[0077] Preparation of N,N-dimethylformamide solution of poly-N-isopropylacrylamide: by weight, 28 parts of poly-N-isopropylacrylamide and 72 parts of N,N-dimethylformamide are stirred for 30 min;

[0078] Add 0.8 parts of cage-type polysilsesquioxane to a poly(N-isopropylacrylamide) N,N-dimethylformamide solution and stir for 30 min. Then add 0.8 parts of low-temperature unblocking isocyanate and 0.08 parts of 2-ethyl-4-methylimidazole and stir for 30 min to obtain the finishing agent.

[0079] b. Processing to obtain temperature-sensitive fiber membrane

[0080] At room temperature, the polyacrylonitrile fiber membrane is immersed in the finishing agent, subjected to two dips and two rolls, and then baked at 75°C for 3 minutes to obtain the polyacrylonitrile intelligent temperature-sensing fiber membrane.

[0081] Step 2). Preparation of the finished fiber membrane

[0082] a. Preparation of spinning solution

[0083] At room temperature and under nitrogen protection, 6 parts by weight of N-isopropylacrylamide were added to 94 parts by weight to prepare an aqueous solution of N-isopropylacrylamide. The solution was stirred for 30 min, then 0.35 parts of N,N-methylenebisacrylamide and 0.35 parts of ammonium persulfate were added and stirred for 30 min. Subsequently, 0.8 parts of low-temperature unblocking isocyanate were added and the solution was stirred for another 30 min. Finally, 5.5 parts of sodium alginate were added to prepare the fiber core spinning solution.

[0084] b. Production of fiber membrane finished products

[0085] The spinning solution is the fiber core, and a 500mM calcium chloride solution is introduced into the sheath layer. Microfluidic spinning is performed on the surface of the polyacrylonitrile intelligent temperature-sensing fiber membrane obtained in step 1) to form a gel fiber layer with a core-sheath structure, thus obtaining the finished fiber membrane. The microfluidic spinning temperature is 26℃, the spinning rate is 45rad / min, and the flow rate is 28uL / s.

[0086] Example 5

[0087] 1) Preparation of temperature-sensitive fiber membrane

[0088] a. Preparation of finishing agent

[0089] Preparation of N,N-dimethylformamide solution of poly-N-isopropylacrylamide: by weight, 30 parts of poly-N-isopropylacrylamide and 70 parts of N,N-dimethylformamide are stirred for 30 min;

[0090] Add 1 part of cage-type polysilsesquioxane to a poly(N-isopropylacrylamide) N,N-dimethylformamide solution and stir for 30 min. Then add 1 part of low-temperature unblocking isocyanate and 0.1 part of 2-ethyl-4-methylimidazolium and stir for 30 min to obtain the finishing agent.

[0091] b. Processing to obtain temperature-sensitive fiber membrane

[0092] At room temperature, the polyacrylonitrile fiber membrane is immersed in the finishing agent, subjected to two dips and two rolls, and then baked at 80°C for 3 minutes to obtain the polyacrylonitrile intelligent temperature-sensing fiber membrane.

[0093] Step 2). Preparation of the finished fiber membrane

[0094] a. Preparation of spinning solution

[0095] At room temperature and under nitrogen protection, 7 parts by weight of N-isopropylacrylamide were added to 93 parts by weight to prepare an aqueous solution of N-isopropylacrylamide. The solution was stirred for 30 min, then 0.4 parts of N,N-methylenebisacrylamide and 0.4 parts of ammonium persulfate were added and stirred for 30 min. Then, 1 part of low-temperature unblocking isocyanate was added and stirred for another 30 min. Finally, 6 parts of sodium alginate were added to prepare the fiber core spinning solution.

[0096] b. Production of fiber membrane finished products

[0097] The spinning solution is the fiber core, and a 500mM calcium chloride solution is introduced into the sheath layer. Microfluidic spinning is performed on the surface of the polyacrylonitrile intelligent temperature-sensing fiber membrane obtained in step 1) to form a gel fiber layer with a core-sheath structure, thus obtaining the finished fiber membrane. The microfluidic spinning temperature is 30℃, the spinning rate is 50rad / min, and the flow rate is 30uL / s.

[0098] The finished products of the above embodiments were subjected to the following tests, and the test standards are as follows:

[0099] Moisture permeability test shall be conducted in accordance with GB / T 12704.2-2009 standard;

[0100] Air permeability testing was conducted according to GB / T5453-1997 standard;

[0101] The water wash resistance test was conducted according to the GB / T8629-2017 standard.

[0102] Abrasion resistance test, conducted according to ASTM D3884-2013 standard;

[0103] Cumulative unidirectional transfer index and liquid water dynamic transfer index were tested according to AATCC 195 standard;

[0104] Flexibility test: The flexibility test was conducted according to the test method reported by Zhang Xiayun et al. (ZHANG X, LI TT, WANG Z, et al. Fabrication and mass production of TPU / Silica / STF coated aramid fabric with excellent flexibility and quasi-staticstab resistance for versatile protection[J]. Progress in Organic Coatings, 2021, 151:106088). The sample size was 50×51mm. 2Place the 0mm-13mm portion of the sample on a horizontal platform and fix it in place. Extend the remaining 38mm portion to the outer edge of the platform. Suspend a 20g weight at the end of the sample and let it hang naturally. Measure the height of the hanging end of the sample compared to the horizontal end without the weight. The higher the height, the better the flexibility of the fabric.

[0105] In the water contact angle test, water droplets were dropped from the polyacrylonitrile fiber layer of the functional fiber membrane product of each embodiment.

[0106] The performance parameters of the fiber membrane products from the above embodiments are as follows:

[0107]

[0108]

[0109] The performance parameters of the fiber membranes from the above embodiments after five water washes are as follows:

[0110]

[0111] Test data shows that the functional fiber membrane product of this patent application possesses durable intelligent temperature-sensing and regulating properties. Furthermore, when the ambient temperature is below 38℃, the functional fiber membrane product exhibits hydrophilic and hygroscopic characteristics. Whether before or after washing, the moisture permeability of the composite fiber membrane at room temperature is significantly higher than that at 38℃, mainly due to the strong hygroscopicity of the composite membrane at room temperature. Regarding unidirectional moisture conduction, the cumulative unidirectional transfer index is negative at room temperature, indicating that the difference in water content between the upper and lower surfaces of the composite fiber membrane is not significant, exhibiting bidirectional moisture absorption characteristics. When the ambient temperature is above 38℃, the functional fiber membrane product exhibits unidirectional moisture conduction characteristics. High temperatures are effectively expelled through directional liquid transport, removing sweat and heat from the body. Simultaneously, water contact angle testing also confirms that when the ambient temperature is above 38℃, the polyacrylonitrile membrane surface changes from hydrophilic to hydrophobic, allowing it to form a Janus structure with the microfluidic gel fiber layer. This demonstrates that the functional fiber membrane product possesses excellent moisture permeability, breathability, comfort, abrasion resistance, and flexibility, exhibiting superior overall performance.

Claims

1. A functional fiber membrane based on intelligent temperature sensing and automatic humidity regulation, characterized in that, The functional fiber membrane is prepared by the following process steps: Step 1). Preparation of the intelligent temperature-sensing fiber membrane a. Preparation of finishing agent Add cage-type polysilsesquioxane to a poly(N-isopropylacrylamide) N,N-dimethylformamide solution, mix thoroughly, then add low-temperature unblocking isocyanate and 2-ethyl-4-methylimidazole, mix thoroughly, and obtain finishing agent; The N,N-dimethylformamide solution of poly(N-isopropylacrylamide) comprises, by weight, the following: 70-80 parts of N,N-dimethylformamide 20-30 parts of poly-N-isopropylacrylamide; Based on the solution per hundred parts by weight, the The cage-type polysilsesquioxane is 0.5-1 part. The low-temperature unblocking type of isocyanate is 0.5-1 part. 0.05-0.1 parts of 2-ethyl-4-methylimidazole; b. Processing to obtain temperature-sensitive fiber membrane At room temperature, a polyacrylonitrile fiber membrane is immersed in a finishing agent, and after two dips and two rolls, it is baked at 60-80℃ to obtain a smart temperature-sensing fiber membrane. Step 2). Preparation of the finished fiber membrane a. Preparation of spinning solution At room temperature and under a nitrogen atmosphere, N,N-methylenebisacrylamide and ammonium persulfate were added to an aqueous solution of N-isopropylacrylamide and mixed thoroughly. Then, low-temperature unblocking isocyanate was added and mixed thoroughly. Finally, sodium alginate was added to obtain the fiber core spinning solution. The mass concentration of the N-isopropylacrylamide aqueous solution is 3-7%. Based on the aforementioned aqueous solution per hundred parts by weight: 0.2-0.4 parts of N,N-methylenebisacrylamide Ammonium persulfate 0.2-0.4 parts Low-temperature unsealing of blocked isocyanates: 0.5-1 part 4-6 parts sodium alginate; b. Production of fiber membrane finished products The spinning solution is the fiber core, and the sheath is introduced with a 500 mM calcium chloride solution. Microfluidic spinning is performed on the surface of the intelligent temperature-sensing fiber membrane obtained in step 1) to form a gel fiber layer with a core-sheath structure, thus obtaining the finished functional fiber membrane.

2. The automatic humidity-regulating functional fiber membrane based on intelligent temperature sensing according to claim 1, characterized in that, Microfluidic spinning was performed at a temperature of 20-30℃, a spinning rate of 30-50 rad / min, and a flow rate of 20-30 uL / s.

3. The automatic humidity regulating functional fiber membrane based on intelligent temperature sensing according to claim 1, characterized in that, The baking process described herein takes 3 minutes.

4. A method for preparing the intelligent temperature-sensing automatic humidity-regulating functional fiber membrane according to any one of claims 1-3.

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