Humidity-responsive polyurethane-based fiber, and preparation method and application thereof

Abstract

The application relates to the technical field of high polymer materials, and provides a humidity-responsive polyurethane-based fiber as well as a preparation method and application thereof, which comprises the following steps: dissolving an oligomer polyol to form a viscous liquid A; adding a diisocyanate monomer into the viscous liquid A and pre-reacting at 60-70 DEG C to obtain a solution B; adding a catalyst into the solution B and reacting at 70-85 DEG C to obtain a solution C; adding x moles of an allyl-containing bisphenol substance into the solution C and continuously reacting at 70-85 DEG C to obtain a solution D; dissolving y moles of a dihydrazide compound in an organic solvent and then adding into the solution D and stirring and reacting at 45-55 DEG C to form a solution E; adding a polyhydroxy compound dropwise into the solution E and reacting at 65-77 DEG C to obtain a solution F; and preparing the solution F into a fiber in a non-solution liquid and airing and drying to obtain the humidity-responsive polyurethane-based fiber. The humidity-responsive polyurethane-based fiber has excellent sensitivity to humidity and excellent flexibility.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of high polymer materials, and particularly relates to a humidity-responsive polyurethane-based fiber and a preparation method and application thereof. BACKGROUND

[0002] In nature, many plants have formed a highly sensitive response mechanism to humidity changes through long-term evolution, and can dynamically adjust their own morphology according to environmental humidity to achieve specific biological functions. For example, the pinecone scales can close to protect the seeds in a humid environment and open to promote seed dissemination in a dry condition through differential movement of swelling by absorbing humidity and shrinking by losing humidity. The essence of the movement is the asymmetric structure deformation driven by the water gradient, which is highly consistent with the humidity actuation principle of the stimulus-responsive polymer in the high polymer material. By simulating the multi-scale structural characteristics and dynamic response behavior of such plant organs, a bionic actuator with environmental self-adaptability can be designed, which has potential application value in intelligent agricultural seeding equipment, environment-responsive soft robots and the like. The biological prototype highlights the guiding significance of the "structure-function integration" design concept in nature to the development of advanced functional materials.

[0003] At present, the research on humidity-responsive actuators still has limitations in morphology and performance. From the preparation process, the existing devices mainly rely on solution casting method for forming. Although this method is simple to operate, the prepared actuators are generally limited to two-dimensional thin film structure, which seriously restricts the application potential of the devices in complex environments. In terms of movement characteristics, due to the limitations of the structural characteristics and water diffusion dynamics of homogeneous materials, traditional thin film actuators can usually only realize simple basic deformation modes such as bending and curling, and it is difficult to reproduce the complex movement behaviors observed in biological systems. More notably, due to the long water transport path and slow diffusion rate in the material, the response speed of such actuators is generally slow (usually in the order of tens of seconds to several minutes), which seriously affects the application efficiency of the actuators in actual scenarios requiring fast response. In view of these technical bottlenecks, a humidity-responsive actuator with one-dimensional fiber structure prepared by wet spinning can be a solution. The unique high aspect ratio characteristics of the fiber material enable it to realize multi-dimensional deformation modes including twisting and stretching, and better simulate the complex movement behavior of natural plant tendrils. In addition, the self-supporting characteristics of the fiber itself effectively avoid the problem of interface failure.

[0004] However, most of the polymer fibers currently have obvious performance degradation in high humidity environment, including modulus drop and deformation ability weakening, and some hydrophilic materials even have structural disintegration in liquid water environment. In the preparation process, it is still challenging to control the microstructure and component distribution of the fiber in the wet spinning process, and the performance difference between batches will affect the reliability of the product. In addition, the existing fiber actuator has limited functional integration, and it is difficult to simultaneously achieve the coordinated optimization of multiple performance indicators such as fast response and large deformation. SUMMARY

[0005] The purpose of the present application is to provide a humidity-responsive polyurethane-based fiber and its preparation method and application, aiming to solve the problem that the existing polymer fiber is difficult to simultaneously achieve the coordinated optimization of multiple performance indicators such as fast response and large deformation.

[0006] To achieve the above application purpose, the technical scheme adopted by the present application is as follows:

[0007] A preparation method of a humidity-responsive polyurethane-based fiber, comprising the following steps:

[0008] S1. Dissolve the dried oligomeric polyol in an organic solvent to form a viscous liquid A, the concentration of the oligomeric polyol in the viscous liquid A is 1-5 g / mL; heat the viscous liquid A to 110-130°C to remove water;

[0009] S2. Slowly drop the diisocyanate monomer into the viscous liquid A from which water has been removed, and stir at 60-70°C for 1.5-2.5 h for pre-reaction to obtain solution B; the molar ratio of oligomeric polyol to diisocyanate monomer is 1:2-1:5.5;

[0010] S3. Add a catalyst to solution B and react at 70-85°C for 2.5-4 h to obtain solution C; the amount of catalyst is 0.01-0.07 wt% of the total mass of all reactants;

[0011] S4. Add x moles of bisphenol to solution C and continue to react at 70-85°C for 2.5-4 h to obtain solution D; the molar ratio of bisphenol to oligomeric polyol is 0:1-1:1;

[0012] S5. Dissolve y moles of diacylhydrazine compound in an organic solvent and then add it dropwise to solution D, and stir at 45-55°C for 4-8 h to form solution E, the molar ratio of diacylhydrazine compound to oligomeric polyol is 1:1-0:1; (x+y):a=1:1, where a is the moles of polyethylene glycol;

[0013] S6. Drop the polyhydroxy compound into solution E, and heat to react at 65~77℃ for 1.5~2.5h to obtain solution F; the amount of polyhydroxy compound is 1~5% of the mass of the oligomer polyol;

[0014] S7. Make solution F into fibers in a non-solution liquid, and dry to obtain the humidity-responsive polyurethane-based fibers.

[0015] As a possible design, the oligomer polyol is polyethylene glycol, polytetramethylene ether glycol, polypropylene glycol, polycarbonate glycol, or polycaprolactone glycol.

[0016] As a possible design, the organic solvent is N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethyl ethylenediamine, dimethyl sulfoxide, acetone, or ethanol.

[0017] As a possible design, the diisocyanate monomer is 4,4'-diisocyanate dicyclohexylmethyl as a possible design, the catalyst is dibutyl tin dilaurate, bismuth isooctoate, or stannous octoate.

[0018] As a possible design, the bisphenol is 2,2'-diallyl bisphenol A, 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(4-hydroxyphenyl)hexafluoropropane, 4,4'- (1-phenylethyl) bisphenol, or 2,2-bis(4-hydroxyphenyl)butane; the dihydrazide compound is adipic acid dihydrazide, malonic acid dihydrazide, sebacic acid dihydrazide, terephthalic acid dihydrazide, or isophthalic acid dihydrazide.

[0019] As a possible design, the polyhydroxy compound is glycerol, triethanolamine, pentaerythritol, trimethylolpropane, or trimethylolethane.

[0020] As a possible design, the heating temperature in step S1 is 120℃, and the stirring time is 2h; the heating temperature in step S2 is 70℃, and the stirring time is 2h; the heating temperature in step S3 is 80℃, and the stirring time is 3h; the heating temperature in step S4 is 80℃, and the stirring time is 2h; the heating temperature in step S5 is 50℃, and the stirring time is 5h; the heating temperature in step S6 is 70℃, and the stirring time is 2h.

[0021] The beneficial effects of the present application are:

[0022] 1. The humidity-responsive polyurethane-based fibers of the present application have good flexibility, with an elongation at break of 1418.7%, a single fiber that has not been broken after being stretched to 4 times the original length, and the fiber after stretching can quickly recover to the original length.

[0023] 2. The humidity-responsive polyurethane-based fiber of the present application has excellent sensitivity. A single fiber can quickly respond within 1s and continuously generate twisting and curling movements under humidity stimulation, and has excellent durability, maintaining good driving effect after multiple humidity driving.

[0024] 3. The humidity-responsive polyurethane-based fiber of the present application maintains sensitive humidity driving effect after being soaked in water for 12 hours and dried at room temperature.

[0025] 4. The humidity-responsive polyurethane-based fiber of the present application is made into fiber twist lines of different counts. The fiber twist lines can also generate curling and rotating movements under humidity stimulation, and can generate unspiral movements, and quickly recover after humidity removal.

[0026] 5. The humidity-responsive polyurethane-based fiber of the present application can be used to make humidity-responsive actuators. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments or prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0028] Figure 1 is the Fourier transform infrared spectrum of the humidity-responsive polyurethane-based fiber prepared in Example 1 of the present application;

[0029] Figure 2 is the flexibility test result diagram of a single humidity-responsive polyurethane-based fiber prepared in Example 1 of the present application;

[0030] Figure 3 is the response behavior diagram of a single humidity-responsive polyurethane-based fiber prepared in Example 1 of the present application under humidity stimulation;

[0031] Figure 4 is the response behavior diagram of a single humidity-responsive polyurethane-based fiber prepared in Example 1 of the present application under humidity stimulation after the single fiber is soaked in deionized water for 12h;

[0032] Figure 5 is the twist line of different counts of the humidity-responsive polyurethane-based fiber prepared in Example 1 of the present application, wherein a is a single fiber twist line, b is a two-fiber twist line, and c is a six-fiber twist line;

[0033] Figure 6 is the humidity response behavior diagram of the six-fiber twist line made of the humidity-responsive polyurethane-based fiber prepared in Example 1 of the present application after twisting under humidity stimulation;

[0034] Figure 7 Figure 6 is a tensile property test result chart of six twisted fiber twisted after twisting of the humidity-responsive polyurethane-based fiber prepared by the embodiment 1 of the present application;

[0035] Figure 8 Figure 5 is a state chart of the solution F prepared by the embodiments and comparative example 2 of the present application, wherein a is the solution prepared by the embodiment 1, b is the solution prepared by the embodiment 2, and c is the solution prepared by the comparative example 2;

[0036] Figure 9 Figure 4 is a scanning electron microscope picture of a single fiber of the humidity-responsive polyurethane-based fiber prepared by the embodiment 1 of the present application;

[0037] Figure 10 Figure 3 is a scanning electron microscope picture of two fibers of the humidity-responsive polyurethane-based fiber prepared by the embodiment 1 of the present application;

[0038] Figure 11 Figure 2 is a scanning electron microscope picture of four fibers of the humidity-responsive polyurethane-based fiber prepared by the embodiment 1 of the present application;

[0039] Figure 12 Figure 1 is a stress-strain curve of the humidity-responsive polyurethane-based fiber prepared by the embodiments 1 and 2 of the present application. DETAILED DESCRIPTION

[0040] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clear and explicit, the present application will be further described in detail below in combination with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not to limit the present application.

[0041] The present application will be described below in combination with specific embodiments.

[0042] Embodiment 1

[0043] The present embodiment discloses a preparation method of a humidity-responsive polyurethane-based fiber, which specifically comprises the following steps:

[0044] 1) 5 g of dried polyethylene glycol (molecular weight 2000) is dissolved in 5 ml of N, N-dimethylformamide, the concentration of the polyethylene glycol is 1 g / ml, forming a viscous liquid A1, which is heated to 120°C and stirred for 2 hours to fully remove moisture.

[0045] 2) A certain amount of 4, 4'-diisocyanate dicyclohexyl methane is slowly added dropwise into the liquid A1, heated to 70°C and stirred for 2 hours for pre-reaction, forming a solution B1, the molar ratio of the polyethylene glycol to the 4, 4'-diisocyanate dicyclohexyl methane is 1:3.5;

[0046] 3) Add dibutyltin dilaurate dropwise into solution B1, heat to 80 °C and continue to react for 3 hours to obtain solution C1, the amount of dibutyltin dilaurate is 0.02 wt% of the total mass of the reactants;

[0047] 4) Add a certain amount of 2,2'-diallyl bisphenol A (x moles) into solution C1, heat to 80 °C and continue to stir for 2 hours to form solution D1, the molar ratio of 2,2'-diallyl bisphenol A to polyethylene glycol is 0.5:1;

[0048] 5) Dissolve adipic acid dihydrazide (y moles) in N,N-dimethylformamide, dropwise add into solution D1, heat to 50 °C and stir for 5 hours to form solution E1, the molar ratio of adipic acid dihydrazide to polyethylene glycol is 0.5:1, (x+y):a = 1:1, where a is the moles of polyethylene glycol;

[0049] 6) Add a certain amount of glycerol dropwise into solution E1, heat to 70 °C and react for 2 hours to obtain solution F1, the amount of glycerol is 1.5% of the mass of polyethylene glycol;

[0050] 7) Add viscous solution F1 (as shown in b of Figure 8 ) into a syringe, slowly push into the stirring deionized water, the size of the needle used is 0.7 mm, collect the fibers and air dry at room temperature to obtain the humidity-responsive polyurethane-based fibers, as shown in a of Figure 8 , named P1H 3.5 D 0.5 A 0.5 .

[0051] Example 2

[0052] 1) Dissolve 5 g of dried polyethylene glycol (molecular weight 2000) in 5 ml of N,N-dimethylformamide, the concentration of polyethylene glycol is 1 g / ml, form viscous liquid A2, heat to 120 °C and stir for 2 hours to remove water.

[0053] 2) Add a certain amount of 4,4'-diisocyanate dicyclohexyl methane slowly dropwise into liquid A2, heat to 70 °C and stir for 2 hours for pre-reaction, form solution B2, the molar ratio of polyethylene glycol to 4,4'-diisocyanate dicyclohexyl methane is 1:5.5;

[0054] 3) Add dibutyltin dilaurate dropwise into solution B2, heat to 80 °C and continue to react for 3 hours to obtain solution C2, the amount of dibutyltin dilaurate is 0.04 wt% of the total mass of the reactants;

[0055] 4) Add a certain amount of 2,2'-diallyl bisphenol A (x moles) into solution C2, heat to 80°C and continue stirring for 2 hours to form solution D2, the molar ratio of 2,2'-diallyl bisphenol A to polyethylene glycol is 0.5:1;

[0056] 5) Dissolve adipic acid dihydrazide (y moles) in N,N-dimethylformamide, dropwise add into solution D2, heat to 50°C and stir for 5 hours to form solution E2, the molar ratio of adipic acid dihydrazide to polyethylene glycol is 0.5:1, (x+y):a=1:1, where a is the molar amount of polyethylene glycol;

[0057] 6) Add a certain amount of glycerol dropwise into solution E2, heat to 70°C and react for 2 hours to obtain solution F2, the amount of glycerol is 1.5% of the mass of the oligomeric polyol;

[0058] 7) Add viscous solution F2 into a syringe, slowly push into the stirring deionized water, the size of the needle used is 0.7 mm, collect the fibers and air dry at room temperature to obtain the humidity-responsive polyurethane-based fibers, as shown in FIG. b of Figure 8 , named P1H 5.5 D 0.5 A 0.5 .

[0059] Comparative Example 1

[0060] 1) Dissolve 5 g of dried polyethylene glycol (molecular weight 2000) in 5 ml of N,N-dimethylformamide to form viscous liquid A3, the concentration of polyethylene glycol is 1 g / ml, heat to 120°C and stir for 2 hours to remove water.

[0061] 2) Add a certain amount of 4,4'-diisocyanate dicyclohexyl methane slowly dropwise into liquid A3, heat to 70°C and stir for 2 hours for pre-reaction to form solution B3, the molar ratio of polyethylene glycol to 4,4'-diisocyanate dicyclohexyl methane is 1:1.5;

[0062] 3) Add dibutyl tin dilaurate dropwise into solution B3, heat to 80°C and continue to react for 3 hours to obtain solution C3, the amount of dibutyl tin dilaurate is 0.02 wt% of the total mass of all reactants;

[0063] 4) Add a certain amount of 2,2'-diallyl bisphenol A (x moles) into solution C3, heat to 80°C and continue stirring for 2 hours to form solution D3, the molar ratio of 2,2'-diallyl bisphenol A to polyethylene glycol is 0.5:1;

[0064] 5) Dissolve adipic acid dihydrazide (y moles) in N,N-dimethylformamide, add it dropwise to solution D3, heat to 50°C and stir for 5 hours to form solution E3. The molar ratio of adipic acid dihydrazide to polyethylene glycol is 0.5:1, (x+y):a=1:1, where a is the molar amount of polyethylene glycol.

[0065] 6) A certain amount of glycerol was added dropwise to solution E3, and the mixture was heated to 70°C for 2 hours to obtain solution F3. The amount of glycerol used was 1.5%.

[0066] 7) Solution F3 has low viscosity and high fluidity, making it unable to form continuous fibers in water.

[0067] Comparative Example 2

[0068] 1) Dissolve 5g of dried polyethylene glycol (molecular weight 2000) in 5ml of N,N-dimethylformamide to form a viscous liquid A4. The concentration of polyethylene glycol is 1g / ml. Heat at 120℃ and stir for 2 hours to remove moisture completely.

[0069] 2) Take a certain amount of 4,4′-diisocyanate dicyclohexylmethane and slowly add it dropwise to liquid A4. Heat to 70°C and stir for 2 hours to carry out the pre-reaction, forming solution B4. The molar ratio of polyethylene glycol to 4,4′-diisocyanate dicyclohexylmethane is 1:6.5.

[0070] 3) Add dibutyltin dilaurate dropwise to solution B4, heat to 80°C and continue the reaction for 3 hours to obtain solution C4. The amount of dibutyltin dilaurate used is 0.02 wt%.

[0071] 4) Add a certain amount of 2,2′-diallyl bisphenol A (x moles) to solution C4, heat to 80℃ and continue stirring for 2 hours to form solution D4. The molar ratio of 2,2′-diallyl bisphenol A to polyethylene glycol is 0.5:1.

[0072] 5) Dissolve adipic acid dihydrazide (y moles) in N,N-dimethylformamide, add it dropwise to solution D4, heat at 50°C and stir for 5 hours to form solution E4. The molar ratio of adipic acid dihydrazide to polyethylene glycol is 0.5:1, (x+y):a=1:1, where a is the molar amount of polyethylene glycol.

[0073] 6) A certain amount of glycerol was added dropwise to solution E, and the mixture was heated to 70°C for 2 hours to obtain solution F4. The amount of glycerol used was 1.5% of the mass of polyethylene glycol.

[0074] 7) The resulting polymer is too viscous, such as... Figure 8 As shown in c, fibers cannot be prepared using a needle.

[0075] The humidity-responsive polyurethane-based fibers prepared in Example 1 were subjected to single-fiber, two-fiber winding, and four-fiber winding electron microscopy. The results are as follows: Figures 9-11 As shown.

[0076] Stress-strain tests were performed on individual fibers of the humidity-responsive polyurethane-based fibers prepared in Examples 1 and 2, and the results are as follows: Figure 12 As shown, by Figure 12 It can be seen that the fiber breaking elongation is 596.86% and 533.84%, respectively, and the tensile strength is 0.98 MPa and 1.54 MPa, respectively. There is no significant difference between the two fibers in terms of moisture response performance.

[0077] The Fourier transform infrared spectrum of the humidity-responsive polyurethane-based fiber prepared in Example 1 is shown below. Figure 1 As shown, by Figure 1 It can be seen that the broad peak formed near the wavenumber is attributed to the absorption peak of the NH bond on the urethane group (-NH(CO)O-) and the urea group (-NHCONH-), 1721 cm⁻¹. -1 and 1639 cm -1 The peaks at this location are attributed to the stretching vibrations of the C=O groups on the urethane and urea groups, respectively. (1533 cm⁻¹) -1 The nearby peaks are due to the NH bending vibration of the urethane group. Additionally, P1H... 3.5 D 0.5 A 0.5 Polymer at 2260 cm -1 No obvious peaks of isocyanate group formation were observed nearby, indicating that in P1H 3.5 D 0.5 A 0.5 All isocyanate groups in the polymer participate in the reaction to generate carbamate and urea functional groups.

[0078] The flexibility test of the humidity-responsive polyurethane-based fiber prepared in Example 1 is as follows: Figure 2 As shown, by Figure 2 It is known that a single fiber does not break even after being stretched to four times its original length, and the stretched fiber can quickly return to its original length and has excellent sensitivity, thus exhibiting good flexibility.

[0079] The humidity-responsive polyurethane-based fiber prepared in Example 1 was used as a stimulus when water mist generated by a humidifier was applied. The results were as follows: Figure 3 As shown, by Figure 3 It is known that a single fiber can respond rapidly within 1 second and continuously generate twisting and curling motions under moisture stimulation, and has excellent durability, maintaining good driving effect even after multiple moisture drives.

[0080] After the humidity-responsive polyurethane-based fiber prepared in Example 1 is soaked in deionized water for 12 hours and dried at room temperature, the fiber still maintains a sensitive humidity-driven effect, as shown in Figure 4

[0081] Different count fiber twist yarns can be obtained by twisting two or several humidity-responsive polyurethane-based fibers prepared in Example 1, Figure 5 Different count fiber twist yarns are shown. The fiber twist yarns can also curl and rotate under the stimulation of humidity.

[0082] Figure 6 The six-count humidity-responsive polyurethane-based fiber twist yarns shown can undergo despiralization under the stimulation of humidity and quickly recover after the humidity is removed.

[0083] The mechanical properties of the six-count fiber twist yarns are tested using an INSTRON 5965 (Norwood, MA) universal tensile testing machine, and the test results are shown in Figure 7 The elongation at break reaches 1418.7%, proving that the fiber twist yarns have excellent flexibility.

[0084] In summary, the preparation method of the present application is simple and easy to implement, and can be widely applied.

[0085] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present application shall be included in the protection scope of the present application.​

Claims

1. A method for preparing a humidity-responsive polyurethane-based fiber, characterized by, The preparation method comprises the following steps: S1. Dissolve the dried oligomer polyol in an organic solvent to form a viscous liquid A, the concentration of the oligomer polyol in the viscous liquid A is 1-5 g / mL; heat the viscous liquid A to 110-130 DEG C to remove water; S2. Slowly drop the diisocyanate monomer into the viscous liquid A from which water is removed, and stir at 60-70 DEG C for 1.5-2.5 h to perform pre-reaction, to obtain solution B; the molar ratio of the oligomer polyol and the diisocyanate monomer is 1:2-1:5.5; S3. Add a catalyst to the solution B, and react at 70-85 DEG C for 2.5-4 h to obtain solution C; the amount of the catalyst is 0.01-0.07 wt% of the total mass of all reactants; S4. Add x moles of bisphenol to the solution C, and continue to react at 70-85 DEG C for 2.5-4 h to obtain solution D; the molar ratio of the bisphenol and the oligomer polyol is 0.5:1; S5. Dissolve y moles of dihydrazide compound in an organic solvent, and drop the solution into the solution D, and stir at 45-55 DEG C for 4-8 h to form solution E; the molar ratio of the dihydrazide compound and the oligomer polyol is 0.5:1; (x+y):a=1:1, wherein a is the molar amount of the oligomer polyol; S6. Drop a polyhydroxy compound into the solution E, and react at 65-77 DEG C for 1.5-2.5 h to obtain solution F; the amount of the polyhydroxy compound is 1-5% of the mass of the oligomer polyol; S7. Form a fiber from the solution F in a non-solution liquid, and dry to obtain the humidity-responsive polyurethane-based fiber; The oligomer polyol is polyethylene glycol; the diisocyanate monomer is 4,4'-diisocyanate dicyclohexyl methane; the bisphenol is 2,2'-diallyl bisphenol A; the dihydrazide compound is adipic acid dihydrazide; and the polyhydroxy compound is glycerol.

2. The method for preparing humidity-responsive polyurethane-based fibers according to claim 1, characterized in that, The organic solvent is N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethyl ethylenediamine, dimethyl sulfoxide, acetone or ethanol.

3. The method for preparing humidity-responsive polyurethane-based fibers according to claim 1, characterized in that, The catalyst is dibutyl tin dilaurate, bismuth isooctoate or stannous octoate.

4. The method for preparing humidity-responsive polyurethane-based fibers according to claim 1, characterized in that, In step S1, the heating temperature is 120 DEG C, and the stirring time is 2 h; in step S2, the heating temperature is 70 DEG C, and the stirring time is 2 h; in step S3, the heating temperature is 80 DEG C, and the stirring time is 3 h; in step S4, the heating temperature is 80 DEG C, and the stirring time is 2 h; in step S5, the heating temperature is 50 DEG C, and the stirring time is 5 h; and in step S6, the heating temperature is 70 DEG C, and the stirring time is 2 h.

5. The humidity-responsive polyurethane-based fiber prepared according to the production method of any one of claims 1 to 4, characterized in that, The humidity-responsive polyurethane-based fiber contains urethane groups and urea groups; the humidity-responsive polyurethane-based fiber completes humidity response within 1 s; and the breaking elongation rate can reach 1418.7%.

6. Application of the humidity-responsive polyurethane-based fiber in claim 5 in a humidity-responsive actuator.

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