Automatic humidity adjusting type functional fiber membrane based on intelligent temperature sensing and preparation method thereof

Abstract

The invention provides an automatic humidity adjusting type functional fiber membrane based on intelligent temperature sensing and a preparation method of the automatic humidity adjusting type functional fiber membrane. According to the method, a novel instantaneous free radical integrated polymerization gel composite fiber layer is constructed on the surface of an intelligent temperature-sensing fiber membrane subjected to padding finishing, and the instantaneous free radical integrated polymerization gel composite fiber layer and the intelligent temperature-sensing fiber membrane are organically combined to form a double-intelligent response system functional fiber membrane finished product, so that the intelligent response characteristics of washing resistance, wear resistance, low-temperature moisture absorption and high-temperature one-way moisture conduction are generally realized; therefore, the raw material fiber becomes the functional intelligent fiber fabric which has multiple protection functions of excellent moisture permeability, air permeability, wear resistance and the like, and can realize washability and ultralight design.

Description

Technical Field

[0001] The invention relates to a functional fiber material and a preparation method thereof, and in particular to a flexible nano fiber material with intelligent temperature sensing characteristics and unidirectional moisture conduction characteristics and a preparation method thereof. Background Art

[0002] Smart flexible materials refer to flexible fiber functional materials that integrate perception, feedback and response, can timely, dynamically and accurately perceive external changes, and imitate certain life system functions. They are widely used in industries such as smart wearables, energy conservation and environmental protection, information technology and biomedical materials, especially in clothing, medical and military aspects. They have great application potential. At present, there are many types of temperature-sensitive fibers, referred to as temperature-sensitive fibers. They are made by introducing intelligent sensing polymers into spinning solutions to prepare textile materials that can accurately respond to and regulate wetting properties according to temperature changes, giving fiber materials intelligent temperature-sensitive response properties. For example:

[0003] Patent document CN 110512305A discloses an antibacterial temperature-controlling nanofiber and a preparation method thereof, wherein N-isopropylacrylamide temperature-sensitive polymer is introduced into a modified sericin solution to prepare a hydrogel, and nanofibers with temperature-controlling properties are obtained by electrospinning.

[0004] Patent document CN 110528112 A discloses an antibacterial temperature-controlled micro-nano fiber and a preparation method thereof, wherein N-isopropylacrylamide is introduced into polyethylene oxide to prepare a spinning solution, and the temperature-controlled nanofiber is prepared by microfluid spinning.

[0005] Another patent document, CN 106758235 B, discloses a thermosensitive antibacterial fabric and a preparation method thereof. A chitosan / poly (N-isopropylacrylamide) spinning solution is designed, and fibers having both antibacterial and thermosensitive properties are prepared by a microfluidic spinning method.

[0006] The existing electrospinning or microfluidic spinning processes generally have the technical drawback of harsh fiber forming conditions. Because the preparation process provided by the literature requires the spinning solution to be jet-formed into fibers under the action of an electrostatic field or a tensile force, it is necessary to use excessive amounts of fiber-forming polymers, such as sericin, polyethylene oxide, etc., as carriers of the spinning solution to overcome the technical problems of being unable to spin and form fibers. However, this makes it impossible to add the intelligent sensing components as needed. Due to the low amount of intelligent temperature-sensitive polymers added, the sensing response is often difficult to reach the required level. Furthermore, in the spinning technology process recorded in the above-mentioned existing technology, the intelligent polymer is simply mixed directly with the fiber-forming polymer as an added component, and the intelligent polymer is excessively exposed in the spun fiber. During use, the intelligent polymer leaks too quickly, resulting in the finished fiber being not washable and wear-resistant, and the intelligent response is not durable.

[0007] It can also be known from the existing technology that the current technical development of temperature-sensitive fibers in the combination of multiple properties is extremely limited. Most of them have only confirmed that the fibers show different wettability at different temperatures. In addition, there are many types of temperature-sensitive polymers with different properties. There is no substantial research on which polymer has a temperature control range that has a significant impact on the application of comfortable and protective clothing textile materials. It is also worth noting that existing research adds antibacterial chitosan to temperature-control polymers to add antibacterial properties, but has not made breakthroughs in more technical properties, especially in the more demanding clothing comfort control performance through unidirectional moisture conduction. On the other hand, the current unidirectional moisture conduction fiber products also have the technical problem of single function. Moreover, the current reality is that the two sensing properties of temperature sensing and humidity guidance are independently developed in technical research and development. In the eyes of many people, including technical researchers, they are considered to be two unrelated technical research and development paths. Patent document CN115071232A discloses a method for preparing an intelligent unidirectional moisture-conducting fabric, which adopts a composite method of a hydrophilic layer and a 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. The composite fiber fabric has only a single unidirectional moisture-conducting property.

[0008] Patent document CN 105966006A discloses a fiber-based waterproof and breathable membrane with intelligent unidirectional moisture conduction function. The hydrophilic fiber layer is prepared by electrospinning one or more of sodium polyacrylate, polyacrylamide and polyvinyl alcohol, and then the polyvinyl butyral bonding layer is sprayed on the surface of the hydrophilic layer. Then the hydrophobic layer is spun on the surface of the bonding layer, and finally heat-treated. The three-layer composite membrane conducts steam through open pores under low humidity conditions and conducts sweat through closed pores under high humidity conditions. It also does not have the ability to conduct liquid through intelligent temperature-sensing and humidity-controlled control. Summary of the invention

[0009] The invention purpose of this patent application is to solve how to give fiber membrane products the characteristics of intelligent control combination and synergistic conversion of temperature sensing and moisture guidance, realize the intelligent conversion of low-temperature moisture absorption and high-temperature unilateral moisture conduction, and at the same time solve the technical problem that the performance is not washable and wear-resistant, resulting in poor durability of intelligent response, and provide an automatic humidity-regulating functional fiber membrane based on intelligent temperature sensing and its preparation method.

[0010] The technical solution of the automatic humidity-adjusting functional fiber membrane based on intelligent temperature sensing provided in this patent application is mainly as follows: an automatic humidity-adjusting functional fiber membrane based on intelligent temperature sensing, and the functional fiber membrane is prepared by the following process steps:

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

[0012] a. Preparation of finishing agent

[0013] Adding cage-type polysilsesquioxane to a N,N-dimethylformamide solution of poly-N-isopropylacrylamide, mixing thoroughly, and then adding low-temperature deblocking blocked isocyanate and 2-ethyl-4-methylimidazole, mixing thoroughly to obtain a finishing agent;

[0014] Wherein, the N,N-dimethylformamide solution of poly-N-isopropylacrylamide is, by weight:

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

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

[0017] Based on the solution per hundred parts by weight, the cage-type polysilsesquioxane is 0.5-1 part

[0018] Low temperature unblocking blocked isocyanate: 0.5-1 part

[0019] 2-ethyl-4-methylimidazole: 0.05-0.1 part;

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

[0021] At room temperature, the polyacrylonitrile fiber membrane is immersed in the finishing agent, and after two immersions and two rollings, it is baked at 60-80℃ to obtain an intelligent temperature-sensitive fiber membrane;

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

[0023] a. Preparation of spinning solution

[0024] At room temperature and in a nitrogen atmosphere, N,N-methylenebisacrylamide and ammonium persulfate are added to an aqueous solution of N-isopropylacrylamide, the mixture is fully mixed, low-temperature deblocked blocked isocyanate is added, the mixture is fully mixed, and sodium alginate is added to obtain a core spinning solution;

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

[0026] Calculated by weight of the aqueous solution:

[0027]

[0028] b.Fiber membrane finished products

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

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

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

[0032] In the patent application, poly N-isopropylacrylamide is the first intelligent temperature control "response switch", which is unblocked at low temperature through double crosslinking of blocked isocyanate and 2-ethyl-4-methylimidazole, and locked into the "cage" molecular structure of cage-type polysilsesquioxane. An interpenetrating network IPN double crosslinking anchoring structure is constructed on the flexible skeleton of the polyacrylonitrile fiber membrane, and poly N-isopropylacrylamide is effectively locked and encapsulated in the IPN three-dimensional network structure, solving the technical problem of functional polymer leakage and achieving wash resistance; secondly, N,N-dimethylformamide solvent is selected; In addition, N,N-dimethylformamide forms micropores in the IPN structure for implementing rapid intelligent moisture control, avoiding the occlusion of fiber gap channels due to the polymer finishing layer on the surface of the fiber membrane, improving the moisture permeability and air permeability of the fiber membrane, and creating conditions for rapid water vapor transmission while obtaining durable intelligent temperature responsiveness: thirdly, the low-temperature deblocking of blocked isocyanate also makes the finishing layer wear-resistant, and replaces the existing high-temperature baking method with a low-energy low-temperature process mode, overcoming the technical problem of the fiber membrane becoming hardened due to high-temperature baking, and maintaining the original flexibility of the fiber.

[0033] The finished temperature-sensitive fiber membrane is used as the substrate, and a "skin-core" structure gel fiber layer of microfluidic free radical integrated polymerization is formed on its surface. The N,N-methylenebisacrylamide and the low-temperature deblocking closed isocyanate are double-crosslinked with the N-isopropylacrylamide NIPAM smart polymer to form a double-crosslinked anchored core layer of the second intelligent "temperature control response switch" of free radical polymerization. The smart polymer is closed by a three-dimensional cross-linked network, and the calcium chloride in the sheath layer and the sodium alginate in the core layer are instantly free radical polymerized in the microfluid spinning to form an inner and outer coated gel. The cross-linked and anchored smart polymer is coated in the core layer, which further avoids the leakage of the smart polymer and achieves high-efficiency washability and durability.

[0034] In the patent scheme of the present invention, the microfluidic realizes the integrated fiber forming and the spinning in one go by free radical one-piece molding. The process method is simple. Because the sodium alginate molecular chain is extended and contains a large number of hydroxyl structural groups, the hydrophilic groups are continuously dissociated during the spinning preparation, so that the microfluidic fiber membrane layer exhibits hydrophilic and hygroscopic properties.

[0035] The finishing layer designed in the present application contains both hydrophilic amide groups and hydrophobic isopropyl groups in the structure of the poly N-isopropylacrylamide polymer. The polymer will show two change modes of volume swelling or shrinking near the low critical temperature LCST. The present application utilizes the hydrogen bonding effect between the hydrophilic groups on its molecular chain and the surrounding water molecules and the hydrophobic association effect between the hydrophobic groups to cause wettability transformation, so that the final product of the present application has the performance of intelligent wettability regulation: when the ambient temperature is lower than the LCST of 38°C, the hydrogen bonding between the amide groups of the poly N-isopropylacrylamide and the water molecules on the finished polyacrylonitrile fiber membrane offsets the hydrophobic effect between the isopropyl groups, and the molecular chain is fully swollen and stretched by the surrounding water vapor. At this time, the functional fiber membrane shows hydrophilic wettability. At the same time, the composite fiber layer with the sodium alginate gel microfluidic shows a double-channel hydrophilic moisture absorption characteristic as a whole; when the ambient temperature is 38°C and above The hydrogen bonding force between the hydrophilic amide groups of poly (N-isopropylacrylamide) and water molecules is greatly reduced. At the same time, the hydrophobic association between the isopropyl groups is enhanced. The finished polyacrylonitrile fiber membrane shows hydrophobicity, and 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 synergistically, and under the "push-pull" action of droplet gravity, Young-Laplace force and capillary tension, the droplet enters a unidirectional moisture conduction mode, which can complete the rapid evaporation function of sweat, etc., especially as a fabric for medical, military or sports protective clothing, it can automatically convert into a unidirectional moisture conduction process of liquid directional transmission when the external ambient temperature exceeds 38°C, quickly discharge body sweat, and achieve the technical purpose of regulating the wetting performance based on automatic temperature sensing, which greatly improves the wearing comfort of the functional fiber membrane through intelligent regulation.

[0036] To sum up, this technical solution constructs a new type of instantaneous free radical integrated polymerization gel composite fiber layer on the surface of the impregnated and rolled smart temperature-sensitive fiber membrane. The organic combination of the two constitutes a "double smart response system" functional fiber membrane product. Its microstructure encapsulates cross-linked anchored smart polymers. On the basis of maintaining the original flexibility of the fiber membrane, its microchannels and micropores create conditions for the construction of organic regulation of the double-layer wetting gradient after smart temperature sensing and the effective performance of its performance. The functional fiber membrane product generally realizes the smart response characteristics of washability, wear resistance, low-temperature moisture absorption, and high-temperature unidirectional moisture conduction, making the raw fiber a functional intelligent fiber fabric with multiple protective functions such as excellent moisture permeability, breathability, wear resistance, and can achieve washability and ultra-light design. DETAILED DESCRIPTION

[0037] The following examples will further illustrate the technical content of the automatic humidity-adjusting functional fiber membrane based on intelligent temperature sensing and its preparation method of this patent application, and explain its application technical 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): 20 parts of poly (N-isopropylacrylamide) and 80 parts of N,N-dimethylformamide by weight, stirring for 30 minutes;

[0042] Add 0.5 parts of cage-type polysilsesquioxane to the N,N-dimethylformamide solution of poly-N-isopropylacrylamide, stir for 30 minutes, then add 0.5 parts of low-temperature deblocking blocked isocyanate and 0.05 parts of 2-ethyl-4-methylimidazole and stir for 30 minutes to obtain a finishing agent;

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

[0044] At room temperature, the polyacrylonitrile fiber membrane was immersed in the finishing agent, and after two immersions and two rollings, it was baked at 60° C. for 3 minutes to obtain the polyacrylonitrile intelligent temperature-sensitive fiber membrane.

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

[0046] a. Preparation of spinning solution

[0047] At room temperature and under nitrogen protection, 3 parts of N-isopropylacrylamide were added to 97 parts of water by weight to prepare an N-isopropylacrylamide aqueous solution, which was stirred for 30 minutes, and 0.2 parts of N,N-methylenebisacrylamide and 0.2 parts of ammonium persulfate were added, and stirred for 30 minutes, and then 0.5 parts of low-temperature deblocking blocked isocyanate were added, and stirring was continued for 30 minutes, and finally 4 parts of sodium alginate were added to prepare a core spinning solution;

[0048] b.Fiber membrane finished products

[0049] The spinning solution is the fiber core, and the sheath layer is introduced with a 500 mM calcium chloride solution, and microfluid spinning is performed on the surface of the polyacrylonitrile intelligent temperature-sensitive fiber membrane obtained in step 1) to form a gel fiber layer with a skin-core structure, thereby obtaining a finished fiber membrane. The microfluid spinning temperature is 20°C, the spinning rate is 30 rad / min, and the flow rate is 20 uL / 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): 23 parts of poly (N-isopropylacrylamide) and 77 parts of N,N-dimethylformamide by weight, stirring for 30 minutes;

[0054] Add 0.6 parts of cage-type polysilsesquioxane to the N,N-dimethylformamide solution of poly-N-isopropylacrylamide, stir for 30 minutes, then add 0.6 parts of low-temperature deblocking blocked isocyanate and 0.06 parts of 2-ethyl-4-methylimidazole and stir for 30 minutes to obtain a finishing agent;

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

[0056] At room temperature, the polyacrylonitrile fiber membrane was immersed in the finishing agent, and after two immersions and two rollings, it was baked at 65° C. for 3 minutes to obtain the polyacrylonitrile intelligent temperature-sensitive fiber membrane.

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

[0058] a. Preparation of spinning solution

[0059] At room temperature and under nitrogen protection, 4 parts of N-isopropylacrylamide were added to 96 parts of water by weight to prepare an N-isopropylacrylamide aqueous solution, which was stirred for 30 minutes, and 0.25 parts of N,N-methylenebisacrylamide and 0.25 parts of ammonium persulfate were added, and stirred for 30 minutes, and then 0.6 parts of low-temperature deblocking blocked isocyanate were added, and stirring was continued for 30 minutes, and finally 4.5 parts of sodium alginate were added to prepare a core spinning solution;

[0060] b.Fiber membrane finished products

[0061] The spinning solution is the fiber core, and the sheath layer is introduced with a 500 mM calcium chloride solution, and microfluid spinning is performed on the surface of the polyacrylonitrile intelligent temperature-sensitive fiber membrane obtained in step 1) to form a gel fiber layer with a skin-core structure, thereby obtaining a finished fiber membrane. The microfluid spinning temperature is 22° C., the spinning rate is 33 rad / min, and the flow rate is 22 uL / 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): 26 parts of poly (N-isopropylacrylamide) and 74 parts of N,N-dimethylformamide by weight, stirring for 30 minutes;

[0066] Add 0.7 parts of cage-type polysilsesquioxane to the N,N-dimethylformamide solution of poly-N-isopropylacrylamide, stir for 30 minutes, then add 0.7 parts of low-temperature deblocking blocked isocyanate and 0.07 parts of 2-ethyl-4-methylimidazole and stir for 30 minutes to obtain a finishing agent;

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

[0068] At room temperature, the polyacrylonitrile fiber membrane was immersed in the finishing agent, and after two immersions and two rollings, it was baked at 70° C. for 3 minutes to obtain the polyacrylonitrile intelligent temperature-sensitive fiber membrane.

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

[0070] a. Preparation of spinning solution

[0071] At room temperature and under nitrogen protection, 5 parts of N-isopropylacrylamide were added to 95 parts of water by weight to prepare an N-isopropylacrylamide aqueous solution, which was stirred for 30 minutes, and 0.3 parts of N,N-methylenebisacrylamide and 0.3 parts of ammonium persulfate were added, and stirred for 30 minutes, and then 0.7 parts of low-temperature deblocking blocked isocyanate were added, and stirring was continued for 30 minutes, and finally 5 parts of sodium alginate were added to prepare a core spinning solution;

[0072] b.Fiber membrane finished products

[0073] The spinning solution is the fiber core, and the sheath layer is introduced with a 500 mM calcium chloride solution, and microfluid spinning is performed on the surface of the polyacrylonitrile intelligent temperature-sensitive fiber membrane obtained in step 1) to form a gel fiber layer with a skin-core structure to obtain a finished fiber membrane. The microfluid spinning temperature is 23° C., the spinning rate is 40 rad / min, and the flow rate is 25 uL / 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): 28 parts of poly (N-isopropylacrylamide) and 72 parts of N,N-dimethylformamide by weight, stirring for 30 minutes;

[0078] Add 0.8 parts of cage-type polysilsesquioxane to the N,N-dimethylformamide solution of poly-N-isopropylacrylamide, stir for 30 minutes, then add 0.8 parts of low-temperature deblocking blocked isocyanate and 0.08 parts of 2-ethyl-4-methylimidazole and stir for 30 minutes to obtain a finishing agent;

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

[0080] At room temperature, the polyacrylonitrile fiber membrane was immersed in the finishing agent, and after two immersions and two rollings, it was baked at 75° C. for 3 minutes to obtain the polyacrylonitrile intelligent temperature-sensitive fiber membrane.

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

[0082] a. Preparation of spinning solution

[0083] At room temperature and under nitrogen protection, 6 parts of N-isopropylacrylamide were added to 94 parts of water by weight to prepare an N-isopropylacrylamide aqueous solution, which was stirred for 30 minutes, and 0.35 parts of N,N-methylenebisacrylamide and 0.35 parts of ammonium persulfate were added, and stirred for 30 minutes, and then 0.8 parts of low-temperature deblocking blocked isocyanate were added, and stirring was continued for 30 minutes, and finally 5.5 parts of sodium alginate were added to prepare a core spinning solution;

[0084] b.Fiber membrane finished products

[0085] The spinning solution is the fiber core, and the sheath layer is introduced with a 500 mM calcium chloride solution, and microfluid spinning is performed on the surface of the polyacrylonitrile intelligent temperature-sensitive fiber membrane obtained in step 1) to form a gel fiber layer with a skin-core structure, thereby obtaining a finished fiber membrane. The microfluid spinning temperature is 26°C, the spinning rate is 45 rad / min, and the flow rate is 28 uL / 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): 30 parts of poly (N-isopropylacrylamide) and 70 parts of N,N-dimethylformamide by weight, stirring for 30 minutes;

[0090] Add 1 part of cage-type polysilsesquioxane to the N,N-dimethylformamide solution of poly-N-isopropylacrylamide, stir for 30 minutes, then add 1 part of low-temperature deblocking blocked isocyanate and 0.1 part of 2-ethyl-4-methylimidazole and stir for 30 minutes to obtain a finishing agent;

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

[0092] At room temperature, the polyacrylonitrile fiber membrane was immersed in the finishing agent, and after two immersions and two rollings, it was baked at 80° C. for 3 minutes to obtain the polyacrylonitrile intelligent temperature-sensitive fiber membrane.

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

[0094] a. Preparation of spinning solution

[0095] At room temperature and under nitrogen protection, 7 parts of N-isopropylacrylamide were added to 93 parts of water by weight to prepare an N-isopropylacrylamide aqueous solution, which was stirred for 30 minutes, and 0.4 parts of N,N-methylenebisacrylamide and 0.4 parts of ammonium persulfate were added, and stirred for 30 minutes, and then 1 part of low-temperature deblocking blocked isocyanate was added, and stirring was continued for 30 minutes, and finally 6 parts of sodium alginate were added to prepare a core spinning solution;

[0096] b.Fiber membrane finished products

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

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

[0099] Water vapor permeability test, in accordance with GB / T 12704.2-2009 standard test;

[0100] Air permeability test, tested according to GB / T5453-1997 standard;

[0101] Washability test, tested in accordance with GB / T8629-2017 standard;

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

[0103] Cumulative one-way transmission index and liquid water dynamic transmission index are 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. Facile fabrication and mass production of TPU / Silica / STF coated aramid fabric with excellent flexibility and quasi-static stab resistance for versatile protection [J]. Progress in Organic Coatings, 2021, 151: 106088). The sample size was 50×51 mm. 2Place the 0mm-13mm portion of the sample on a horizontal platform and fix it. Extend the remaining 38mm portion to the outside of the platform. Hang a 20g weight on the end of the sample and let it hang naturally. Measure the height between the hanging end of the sample and 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 drops are dropped into the polyacrylonitrile fiber layer of the functional fiber membrane product of each embodiment.

[0106] The performance parameters of the finished fiber membranes of the above-mentioned embodiments are as follows:

[0107]

[0108]

[0109] After the finished fiber membranes of the above-mentioned embodiments were washed 5 times, the performance parameters were as follows:

[0110]

[0111] It can be seen from the test data that the functional fiber membrane product of this patent application has durable intelligent temperature sensing and control performance; and when the ambient temperature is lower than 38°C, the functional fiber membrane product presents hydrophilic hygroscopic properties. Whether before or after washing, the moisture permeability of the composite fiber membrane at room temperature is significantly higher than that of the membrane at 38°C, mainly due to the strong hygroscopicity of the composite membrane at room temperature. In terms of unidirectional moisture conduction performance, under room temperature conditions, the cumulative unidirectional transmission index is negative, indicating that the water volume on the upper and lower surfaces of the composite fiber membrane is not much different, showing bidirectional hygroscopic properties; when the ambient temperature is higher than 38°C, the functional fiber membrane product presents unidirectional moisture conduction properties, and high temperature is transmitted through liquid directionally, effectively expelling sweat and heat from the body. At the same time, the water contact angle test also confirms that when the ambient temperature is higher than 38°C, the surface of the polyacrylonitrile membrane changes from hydrophilic to hydrophobic, and can construct a Janus structure with the microfluidic gel fiber layer. It proves that the functional fiber membrane product has good moisture permeability, breathability, comfort, wear resistance and flexibility, and its comprehensive performance is excellent.

Claims

1. A functional fiber membrane with automatic humidity control based on intelligent temperature sensing, characterized in that: The functional fiber membrane is prepared by the following process steps: Step 1). Preparation of intelligent temperature-sensitive fiber membrane a. Preparation of finishing agent Adding cage-type polysilsesquioxane to a N,N-dimethylformamide solution of poly-N-isopropylacrylamide, mixing thoroughly, adding low-temperature deblocking blocked isocyanate and 2-ethyl-4-methylimidazole, mixing thoroughly to obtain a finishing agent; Wherein, the N,N-dimethylformamide solution of poly-N-isopropylacrylamide is, by weight: 70-80 parts of N,N-dimethylformamide 20-30 parts of poly (N-isopropylacrylamide); Based on the solution per hundred parts by weight, the Cage polysilsesquioxane 0.5-1 part Low temperature unblocking blocked isocyanate: 0.5-1 part 2-ethyl-4-methylimidazole: 0.05-0.1 part; b. Finishing to obtain temperature-sensitive fiber membrane At room temperature, the polyacrylonitrile fiber membrane is immersed in the finishing agent, and after two immersions and two rollings, it is baked at 60-80℃ to obtain an intelligent temperature-sensitive fiber membrane; Step 2). Preparation of finished fiber membrane a. Preparation of spinning solution At room temperature and in a nitrogen atmosphere, N,N-methylenebisacrylamide and ammonium persulfate are added to an aqueous solution of N-isopropylacrylamide, the mixture is fully mixed, low-temperature deblocked blocked isocyanate is added, the mixture is fully mixed, and sodium alginate is added to obtain a core spinning solution; Wherein, the mass concentration of the N-isopropylacrylamide aqueous solution is 3-7%; Calculated by weight of the aqueous solution: b.Fiber membrane finished products The spinning solution is the fiber core, and a 500 mM calcium chloride solution is introduced into the sheath layer. Microfluid spinning is performed on the surface of the intelligent temperature-sensitive fiber membrane obtained in step 1) to form a gel fiber layer with a skin-core structure, thereby obtaining a functional fiber membrane product.

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

3. The automatic humidity-control functional fiber membrane based on intelligent temperature sensing according to claim 1 is characterized in that: The baking time is 3 minutes.

4. A method for preparing the automatic humidity-adjusting functional fiber membrane based on intelligent temperature sensing as described in any one of claims 1-3.

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