Functionalized microporous elastic fibers and methods for making the same

Abstract

This invention provides a functionalized microporous elastic fiber and its preparation method. The preparation process involves first dissolving a predetermined mass of polyurethane prepolymer in a binary solvent to obtain a spinning solution; then mixing silicone oil and an emulsifier to obtain solution A; simultaneously, uniformly dispersing functional particles in deionized water to obtain dispersion B; then adding dispersion B to solution A and mixing to obtain an emulsion coagulation bath; finally, placing the prepared spinning solution in a spinning device and ejecting it through spinning holes, allowing the spun fibers to enter the prepared emulsion coagulation bath for a predetermined time, followed by stretching and drying to obtain functionalized microporous elastic fibers. This invention controls the difference in compatibility between the binary solvent and the water and silicone oil in the emulsion coagulation bath, enabling rapid shaping of the spun fibers and simultaneously achieving the preparation of functionalized fibers. Based on the principle of phase separation, by controlling the solvent ratio and the degree of emulsification in the coagulation bath, and further through stretching and high-temperature drying and setting, porous functionalized elastic fibers are obtained.

Description

Technical Field

[0001] This invention relates to the field of elastic fiber preparation technology, and in particular to a functionalized microporous elastic fiber and its preparation method. Background Technology

[0002] Spandex is an elastic fiber composed of urethane block copolymers. It has advantages such as good resilience and abrasion resistance, and is widely used in clothing for various purposes due to its huge market demand.

[0003] Non-solvent phase separation is a simple method for fiber preparation. The principle of non-solvent phase separation is to first dissolve the polymer in a solvent to form a homogeneous solution; then, a reagent with stronger miscibility with the solvent (called an extractant) is slowly added to extract the solvent, forming a two-phase structure with the polymer as the continuous phase and the solvent as the dispersed phase. The solvent is then removed to obtain a polymer with a specific porous structure. Patent application CN202210479446.1 discloses a method for preparing blended membranes using a solvent-free phase separation method. First, polyvinylidene fluoride (PVDF) and meta-aramid are dissolved in acetone and N,N-dimethylacetamide, followed by the addition of glycerol to obtain a casting solution. Then, glycerol and N,N-dimethylacetamide are prepared into a first-stage coagulation bath, and N,N-dimethylacetyl and deionized water are prepared into a second-stage coagulation bath. The casting solution is poured onto a substrate and formed into a liquid film using an automatic film scraper. The film is then slowly and uniformly placed into the first-stage coagulation bath, removed, and placed into the second-stage coagulation bath. The formed PVDF / meta-aramid blended membrane is then removed from the coagulation bath and immersed in deionized water to remove residual solvents and additives. After rinsing and drying, the blended membrane is obtained. This method requires multiple stages of coagulation bath replacement, making the preparation process cumbersome. Furthermore, the resulting porous membrane has a relatively simple structure and cannot be used to prepare functional materials with surface-functionalized particle layers.

[0004] In view of this, it is necessary to design an improved functionalized microporous elastic fiber and its preparation method to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide a functionalized microporous elastic fiber and its preparation method. In the preparation process, a polyurethane prepolymer is first dissolved in a binary solvent, and then an emulsion coagulation bath composed of water and silicone oil is prepared. The compatibility between the binary solvent and the water and silicone oil in the emulsion coagulation bath is controlled to cause non-solvent-induced phase separation in the coagulation bath. The spinning fine stream is rapidly formed. Under the action of non-solvent-induced phase separation, stretching and high-temperature drying and shaping, a functionalized microporous elastic fiber with a core-shell structure with multiple pore structures, rich pores and functional particles attached to the pore walls and surface is obtained.

[0006] To achieve the above-mentioned objective, this invention provides a method for preparing functionalized microporous elastic fibers, comprising the following steps:

[0007] S1. Dissolve a pre-defined mass of polyurethane prepolymer in a binary solvent to obtain a spinning solution;

[0008] S2. Mix silicone oil and emulsifier to obtain solution A; at the same time, uniformly disperse functional particles in deionized water to obtain dispersion B; then add dispersion B to solution A and mix to obtain emulsion coagulation bath;

[0009] S3. The spinning solution prepared in step S1 is placed in a spinning device and sprayed out through the spinning hole. The spinning fine stream enters the emulsion coagulation bath prepared in step S2 and is treated for a preset time. After stretching and drying, functionalized microporous elastic fibers are obtained.

[0010] As a further improvement of the present invention, in step S1, the binary solvent includes a first solvent and a second solvent that are miscible with each other; the first solvent is miscible with both silicone oil and deionized water, but not with silicone oil; the second solvent is miscible with deionized water; and the mass ratio of the first solvent to the second solvent is 2:8-8:2.

[0011] As a further improvement of the present invention, the first solvent is tetrahydrofuran; the second solvent includes one of N,N-dimethylformamide, N,N-dimethylacetamide, and dimethyl sulfoxide.

[0012] As a further improvement of the present invention, in the spinning solution, the mass fraction of polyurethane prepolymer is 20%-45%, and the mass fraction of binary solvent is 55%-80%.

[0013] As a further improvement of the present invention, in step S2, the mass fraction of the emulsion coagulation bath is 0.5%-2%, the mass fraction of the functional particles is 0.1%-5%, and the mass fraction of the total of silicone oil and deionized water is 93%-99.7%.

[0014] As a further improvement of the present invention, the mass ratio of silicone oil to deionized water is 1:9-5:5.

[0015] As a further improvement of the present invention, the silicone oil includes one or more of dimethyl silicone oil, diethyl silicone oil, benzyl silicone oil, hydroxyl silicone oil, and methyl hydrogen silicone oil; the emulsifier includes one of sodium dodecyl sulfate, Tween, Triathon, tetraethyl silicate, and tris(hydroxymethyl)aminomethane; the functional particles include one or a mixture of multiple of conductive carbon black, graphene, carbon nanotubes, titanium dioxide, zirconium dioxide, magnesium oxide, copper oxide, silver nanowires, and boron nitride.

[0016] As a further improvement of the present invention, step S1 specifically involves placing a pre-set mass of polyurethane prepolymer in a binary solvent, mechanically stirring it at 20-30°C for 100-200 min, and then performing vacuum degassing treatment at 20-30°C to obtain a spinning solution.

[0017] As a further improvement of the present invention, step S2 specifically involves mixing silicone oil and emulsifier evenly and heating to 80-100°C to obtain solution A; simultaneously, adding functional particles to deionized water, ultrasonically dispersing, and heating to 80-100°C to obtain dispersion B; then adding dispersion B to solution A, mechanically stirring for 10-30 minutes, and finally emulsifying for 5-60 minutes to obtain an emulsion coagulation bath.

[0018] The present invention also provides a functionalized microporous elastic fiber, which is prepared by the preparation method described above.

[0019] The beneficial effects of this invention are:

[0020] (1) The present invention provides a method for preparing functionalized microporous elastic fibers. First, a polyurethane prepolymer is dissolved in a binary solvent. Then, an emulsion coagulation bath composed of water and silicone oil is prepared. The compatibility between the binary solvent and the water and silicone oil in the emulsion coagulation bath is controlled to cause non-solvent-induced phase separation in the coagulation bath, allowing the spinning fine stream to form rapidly. Based on the principle of non-solvent-induced phase separation, the polyurethane molecular chains are controlled to entangle to different degrees during the forming process, and the polyurethane and deionized water combine with each other to form a first pore structure on the surface and inside of the initially formed fiber. At the same time, functional particles in the emulsion coagulation bath are attached to the surface of the initially formed fiber and the pore walls of the first pore. Then, during the stretching and drying process, the arrangement of the polyurethane molecular chains is further fine-tuned, and the evaporation of water forms a second pore structure again. The functional particles in the emulsion coagulation bath are further attached to the pore walls of the second pore, finally obtaining a functionalized microporous elastic fiber with multiple pore structures, abundant pores, and functional particles attached to both the pore walls and the surface.

[0021] (2) This invention incorporates functional particles into an emulsion coagulation bath, allowing the functional particles to adhere to the surface and pore walls of the fiber while the fiber is rapidly formed, thus rapidly preparing high-performance porous elastic fibers with a core-shell structure in one step. Furthermore, the presence of functional particles can broaden the applications of porous elastic fibers in areas such as UV resistance, antibacterial properties, stain resistance, and degradation of organic pollutants. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in detail below with reference to specific embodiments.

[0023] It should also be noted that, in order to avoid obscuring the present invention with unnecessary details, only the processing steps closely related to the solution of the present invention are shown in the specific embodiments, while other details that are not closely related to the present invention are omitted.

[0024] Additionally, it should be noted that the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0025] This invention provides a method for preparing functionalized microporous elastic fibers, comprising the following steps:

[0026] S1. Preparation of spinning solution:

[0027] First, mix the binary solvent evenly. Then, place the pre-set mass of polyurethane prepolymer into the binary solvent and mechanically stir at 20-30℃ for 100-200 min. After the polyurethane prepolymer is completely dissolved and a homogeneous solution is formed, continue vacuum degassing treatment at 20-30℃ for 100-200 min to obtain the spinning solution.

[0028] In the spinning solution, the mass fraction of the polyurethane prepolymer is 20%-45%, and the mass fraction of the binary solvent is 55%-80%. Specifically, the binary solvent includes a first solvent and a second solvent that are miscible with each other; the first solvent is miscible with both silicone oil and deionized water; the second solvent is miscible with deionized water but not with silicone oil; the mass ratio of the first solvent to the second solvent is 2:8-8:2. The first solvent is tetrahydrofuran; the second solvent includes one of N,N-dimethylformamide, N,N-dimethylacetamide, and dimethyl sulfoxide. (N,N-dimethylformamide has a higher miscibility with water than tetrahydrofuran.)

[0029] This setup provides favorable conditions for diverse replacements between different solvents in the subsequent coagulation bath, thereby forming fibers with different and abundant pore structures.

[0030] S2. Preparation of emulsion coagulation bath:

[0031] Silicone oil and emulsifier are mixed evenly and heated to 80-100℃ to obtain solution A; at the same time, functional particles are added to deionized water and ultrasonically dispersed for 5-60 minutes to obtain a homogeneous dispersion solution, which is then heated to 80-100℃ to obtain dispersion B; then the hot dispersion B is added to the hot solution A and mechanically stirred for 10-30 minutes, and finally emulsified using an emulsifier for 5-60 minutes to obtain a homogeneous emulsion coagulation bath.

[0032] In the emulsion coagulation bath, the mass fraction of emulsifier is 0.5%-2%, the mass fraction of functional particles is 0.1%-5%, and the total mass fraction of silicone oil and deionized water is 93%-99.7%. The mass ratio of silicone oil to deionized water is 1:9-5:5, that is, the amount of water used is greater than or equal to the amount of silicone oil. This emulsion coagulation bath can be called an oil-in-water emulsion system.

[0033] Specifically, the silicone oil includes one or more of dimethyl silicone oil, diethyl silicone oil, benzyl silicone oil, hydroxyl silicone oil, and methyl hydrogen silicone oil; the emulsifier includes one of sodium dodecyl sulfate, Tween, Triathon, tetraethyl silicate, and tris(hydroxymethyl)aminomethane; and the functional particles include one or a mixture of multiple of conductive carbon black, graphene, carbon nanotubes, titanium dioxide, zirconium dioxide, magnesium oxide, copper oxide, silver nanowires, and boron nitride.

[0034] During this process, a specific feeding method is used to achieve uniform dispersion of silicone oil, water, and functional particles.

[0035] S3. Spinning and forming:

[0036] The spinning solution prepared in step S1 is placed in a spinning device and sprayed out through the spinning hole. The spinning fine stream enters the emulsion coagulation bath prepared in step S2 and is treated for 15-30 minutes. After stretching, it is dried and shaped at a high temperature of 40-80℃ to obtain functionalized microporous elastic fibers.

[0037] The stretching ratio is 1-5 times.

[0038] In this process, the spun yarns ejected from the spinneret enter the emulsion coagulation bath. The first solvent in the binary solvent of the spun yarns is extracted by the silicone oil in the emulsion coagulation bath, causing the spun yarns to form rapidly. At the same time, it also replaces the deionized water in the emulsion coagulation bath. The two processes are in a competitive relationship. The second solvent replaces the deionized water in the emulsion coagulation bath, and the first and second solvents are still in a competitive relationship during the replacement process with deionized water. Under the simultaneous existence and competition of the above different phase separation processes, the polyurethane molecular chains are entangled to varying degrees, and the polyurethane and deionized water combine with each other to form the first pore structure on the surface and inside of the initially formed fiber. At the same time, functional particles in the emulsion coagulation bath attach to the surface of the initially formed fiber and the pore walls of the first pores. Next, during the stretching process, the intertwining of polyurethane molecular chains undergoes further changes and becomes more stable, and the first pore structure is also finely adjusted. After high-temperature drying, as the moisture evaporates, the arrangement of polyurethane molecular chains is further finely adjusted, and the evaporation of moisture again forms a second pore structure. In the emulsion coagulation bath, functional particles further adhere to the pore walls of the second pores, ultimately resulting in functionalized microporous elastic fibers with multiple pore structures, abundant pores, and functional particles attached to both the pore walls and the surface.

[0039] The present invention will now be described in detail through specific embodiments.

[0040] Example 1

[0041] A method for preparing functionalized microporous elastic fibers includes the following steps:

[0042] S1. Preparation of spinning solution:

[0043] First, the binary solvent is mixed evenly. Then, a pre-set mass of polyurethane prepolymer is placed in the binary solvent and mechanically stirred at 25°C for 120 minutes. After the polyurethane prepolymer is completely dissolved and a homogeneous solution is formed, vacuum degassing treatment is continued at 25°C for 120 minutes to obtain the spinning solution.

[0044] In the spinning solution, the mass fraction of the polyurethane prepolymer is 35%, and the mass fraction of the binary solvent is 65%. The first solvent is tetrahydrofuran, and the second solvent is N,N-dimethylformamide, meaning the binary solvent is a mixture of tetrahydrofuran and N,N-dimethylformamide (N,N-dimethylformamide is more compatible with water than tetrahydrofuran). The mass ratio of tetrahydrofuran to N,N-dimethylformamide is 3:7.

[0045] S2. Preparation of emulsion coagulation bath:

[0046] Dimethyl silicone oil and sodium dodecyl sulfate emulsifier were mixed evenly and heated to 90°C to obtain solution A. Simultaneously, carbon nanotube functional particles were added to deionized water and ultrasonically dispersed for 30 min to obtain a homogeneous dispersion solution, which was then heated to 90°C to obtain dispersion B. Then, the hot dispersion B was added to the hot solution A and mechanically stirred for 20 min. Finally, the mixture was emulsified using an emulsifier for 30 min to obtain a homogeneous emulsion coagulation bath.

[0047] In the emulsion coagulation bath, the mass fraction of emulsifier was 1.2%, the mass fraction of functional particles was 3%, and the total mass fraction of silicone oil and deionized water was 95.8%. The mass ratio of silicone oil to deionized water was 2:8.

[0048] S3. Spinning and forming:

[0049] The spinning solution prepared in step S1 is placed in a spinning device and sprayed out through the spinning hole. The spinning fine stream enters the emulsion coagulation bath prepared in step S2 and is treated for 15 minutes. After stretching, it is dried and shaped at a high temperature of 60°C to obtain functionalized microporous elastic fibers.

[0050] The stretching factor is 3.

[0051] Example 2 and Comparative Examples 1-2

[0052] A method for preparing functionalized microporous elastic fibers differs from Example 1 in that, in step S1, the mass fractions (i.e., mass percentages) of polyurethane prepolymer and binary solvent in the spinning solution are different. Otherwise, the method is largely the same as in Example 1 and will not be repeated here.

[0053] The functionalized microporous elastic fibers prepared in Examples 1-2 and Comparative Examples 1-2 were subjected to performance tests, and the results are shown in Table 1.

[0054] Table 1 Functionalized microporous elastic fibers prepared in Examples 1-2 and Comparative Examples 1-2

[0055]

[0056] As shown in Table 1, with the increase of polyurethane solid content in the spinning solution, the porosity and elongation at break of the fiber first increase and then decrease, while the elastic Young's modulus fluctuates. This is attributed to the fact that the increase of polyurethane solid content reduces the amount of solvent, making the fiber forming process stable and slow, thus affecting the porosity and mechanical properties of the fiber.

[0057] Examples 3-4 and Comparative Examples 3-4

[0058] A method for preparing functionalized microporous elastic fibers differs from Example 1 in that the mass ratio of tetrahydrofuran and N,N-dimethylformamide in the binary solvent is different in step S1. The rest is roughly the same as in Example 1 and will not be repeated here.

[0059] The functionalized microporous elastic fibers prepared in Examples 3-4 and Comparative Examples 3-4 were subjected to performance tests, and the results are shown in Table 2.

[0060] Table 2 Functionalized microporous elastic fibers prepared in Examples 3-4 and Comparative Examples 3-4

[0061]

[0062] As shown in Table 2, with the increase of tetrahydrofuran content in the binary solvent, the porosity of the fiber gradually decreases, while the elastic Young's modulus and elongation at break first increase and then decrease. This is mainly because with the change of tetrahydrofuran content, the strength of the interaction between solvents during the fiber coagulation bath molding process changes, which alters the synergistic effect of the dual diffusion between different solvents and emulsion system components, causing changes in the pore structure of the fiber and thus affecting the fiber's performance. However, it does not affect the loading of functional particles in the fiber or the functional gain of the fiber.

[0063] Examples 5-6 and Comparative Examples 5-6

[0064] A method for preparing functionalized microporous elastic fibers differs from Example 1 in that the type of binary solvent is different in step S1, while the rest is largely the same as in Example 1 and will not be repeated here.

[0065] The functionalized microporous elastic fibers prepared in Examples 5-6 and Comparative Examples 5-6 were subjected to performance tests, and the results are shown in Table 3.

[0066] Table 3 Functionalized microporous elastic fibers prepared in Examples 5-6 and Comparative Examples 5-6

[0067]

[0068]

[0069] As shown in Table 3, when the binary solvent system changes, and only one solvent is soluble in both water and silicone oil, while the other solvent is insoluble in both water (acetone is very miscible with water) and silicone oil, the porosity of the fiber decreases significantly. This is mainly because, at this time, only the exchange between tetrahydrofuran, water, and silicone oil occurs in the coagulation bath, and the coexistence and competition of diversified substitutions cannot be achieved, which makes the porosity of the fiber decrease significantly, thus affecting the mechanical properties, but does not affect the loading of functional particles in the fiber or the functional gain effect.

[0070] Example 7 and Comparative Examples 7-8

[0071] A method for preparing functionalized microporous elastic fibers differs from Example 1 in that the mass ratio of silicone oil and deionized water is different in step S2. The rest is roughly the same as in Example 1 and will not be repeated here.

[0072] The functionalized microporous elastic fibers prepared in Example 7 and Comparative Examples 7-8 were subjected to performance tests, and the results are shown in Table 4.

[0073]

[0074]

[0075] Table 4 shows the functionalized microporous elastic fibers prepared in Example 7 and Comparative Examples 7-8.

[0076] As shown in Table 4, the porosity changes when the oil-to-water ratio in the emulsion changes. This is due to the change in the miscibility between the solvent system and the emulsion, which affects its mechanical properties. Since the functional particles are uniformly dispersed in deionized water, when the ratio of silicone oil to water changes, it will affect the loading of particles in the fiber and thus affect the functional properties imparted to the fiber.

[0077] Examples 8-10 and Comparative Examples 9-12

[0078] A method for preparing functionalized microporous elastic fibers differs from Example 1 in that, in step S2, the mass fraction (i.e., mass percentage) of the total amount of emulsifier, functional particles, silicone oil, and deionized water in the emulsion coagulation bath is different. Otherwise, it is largely the same as Example 1 and will not be repeated here.

[0079] The functionalized microporous elastic fibers prepared in Examples 8-10 and Comparative Examples 9-12 were subjected to performance tests, and the results are shown in Table 5.

[0080] Table 5 Functionalized microporous elastic fibers prepared in Examples 8-10 and Comparative Examples 9-12

[0081]

[0082] Table 5 shows that the addition of nanoparticles has a relatively small impact on porosity, but a significant impact on the mechanical properties of the fibers. The addition of emulsifiers has a greater impact on fiber porosity. This is because the appropriate amount of emulsifier ensures uniform oil-water dispersion in the emulsion coagulation bath. However, the immiscibility of emulsifiers and binary solvents hinders the molding process, thus affecting the pore structure. These two factors contribute to the influence of emulsifiers on the porosity and mechanical properties of the fibers. Simultaneously, the functional particles are dispersed in a deionized water system; when the emulsion system changes, the corresponding loading of functional particles in the fibers changes.

[0083] Examples 11-12 and Comparative Example 13

[0084] A method for preparing functionalized microporous elastic fibers differs from Example 1 in that the draw ratio is different in step S3, while the rest is largely the same as in Example 1 and will not be described again here.

[0085] The functionalized microporous elastic fibers prepared in Examples 11-12 and Comparative Example 13 were subjected to performance tests, and the results are shown in Table 6.

[0086] Table 6. Functionalized microporous elastic fibers prepared in Examples 11-12 and Comparative Example 13.

[0087]

[0088] As shown in Table 6, the fiber porosity decreases as the draw ratio increases, thus affecting its mechanical properties.

[0089] Comparative Example 14

[0090] A method for preparing functionalized microporous elastic fibers differs from Example 1 in that, in step S2, instead of directly preparing an emulsion coagulation bath, solution A is used as the first coagulation bath and dispersion B is used as the second coagulation bath. The spinning fine stream first enters the first coagulation bath and then enters the second coagulation bath. The rest is roughly the same as in Example 1 and will not be repeated here.

[0091] Comparative Example 15

[0092] A method for preparing functionalized microporous elastic fibers differs from Example 1 in that functional particles are added to the spinning solution. Step S1 prepares a spinning solution containing polyurethane prepolymer and functional particles; in step S2, no functional particles are added. The rest is largely the same as in Example 1 and will not be repeated here. In the porous fibers prepared in Comparative Example 16, the functional particles are distributed within the polyurethane, i.e., the functional particles are distributed both inside and on the surface of the fiber.

[0093] Comparative Example 16

[0094] A method for preparing functionalized microporous elastic fibers differs from Example 1 in that, in step S2, no silicone oil or emulsifier is added to the coagulation bath; only water and functional particles are used. That is, the porous fibers are prepared using the traditional wet spinning method. Otherwise, the method is largely the same as in Example 1 and will not be repeated here.

[0095] Comparative Example 17

[0096] A method for preparing functionalized microporous elastic fibers differs from Example 1 in that, in step S2, the solvent of the spinning solution in step S1 is tetrahydrofuran, and no water is added to the coagulation bath in step S2; instead, it is a combination of silicone oil and functional particles. That is, porous fibers are prepared solely through the principle of non-solvent-induced phase separation. Other aspects are largely the same as in Example 1 and will not be repeated here.

[0097] The functionalized microporous elastic fibers prepared in Comparative Examples 14-17 were subjected to performance tests, and the results are shown in Table 7.

[0098] Table 7 shows the functionalized microporous elastic fibers prepared in Comparative Examples 14-17.

[0099] Example Porosity (%) Young's modulus (MPa) Elongation at break (%) Example 1 73 0.31 120.78 Comparative Example 15 58 0.26 109.31 Comparative Example 16 73 0.35 118.62 Comparative Example 17 83 0.19 111.31 Comparative Example 18 0 0.41 98.51

[0100] As shown in Table 7, based on the data from Comparative Example 1, when the spinning fibers are first introduced into the oil coagulation bath and then into the water coagulation bath, the porosity of the fibers decreases significantly. This indicates that the simultaneous occurrence of multiple forms of solvent exchange results in a richer pore structure.

[0101] As can be seen from the data of Comparative Example 16, when porous fibers are prepared using only a single coagulation pure water system, although the porosity is improved, the pore formation principle is that water and coagulation bath undergo double diffusion, resulting in a simple pore structure and some deviation in mechanical properties. Furthermore, without the dispersion of functional particles in the emulsion system, the particles cannot bind tightly to the polymer matrix, thus failing to impart functionality to the elastic fibers.

[0102] The data from Comparative Example 17 show that when fibers are prepared using only a single silicone oil coagulation bath, the solvent diffuses in only one direction, resulting in fibers with virtually no porous structure. This indicates that changes in the coagulation bath system and preparation steps directly affect the pore structure of the fibers. Furthermore, when pure silicone oil is used for spinning, no porous structure is generated, thus directly affecting the mechanical properties.

[0103] In summary, this invention provides a functionalized microporous elastic fiber and its preparation method. The preparation process involves first dissolving a polyurethane prepolymer in a binary solvent, then preparing an emulsion coagulation bath composed of water and silicone oil. The compatibility between the binary solvent and the water and silicone oil in the emulsion coagulation bath is controlled to induce non-solvent-induced phase separation in the coagulation bath, allowing for rapid spinning of fine fibers. Based on the principle of phase separation and utilizing the compatibility of solvents, by controlling the solvent ratio, functionalized microporous elastic fibers with diverse pore structures, abundant pores, and core-shell structures with functional particles attached to the pore walls and surface are obtained. This invention adds functional particles to the emulsion coagulation bath, allowing the functional particles to adhere to the fiber surface and pore walls while the fiber is rapidly formed, enabling the one-step rapid preparation of high-performance functional porous elastic fibers with a core-shell structure. The presence of functional particles can broaden the application fields of porous elastic fibers.

[0104] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for preparing functionalized microporous elastic fibers, characterized in that, Includes the following steps: S1. Dissolve a pre-defined mass of polyurethane prepolymer in a binary solvent to obtain a spinning solution; S2. Mix silicone oil and emulsifier to obtain solution A; at the same time, uniformly disperse functional particles in deionized water to obtain dispersion B; then add dispersion B to solution A and mix to obtain emulsion coagulation bath; S3. The spinning solution prepared in step S1 is placed in a spinning device and sprayed out through the spinning hole. The spinning fine stream enters the emulsion coagulation bath prepared in step S2 and is treated for a preset time. After stretching and drying, functionalized microporous elastic fibers are obtained. In step S1, the binary solvent includes a first solvent and a second solvent that are miscible with each other; the first solvent is miscible with both silicone oil and deionized water; the second solvent is miscible with deionized water but not with silicone oil; the mass ratio of the first solvent to the second solvent is 2:8-8:

2. The first solvent is tetrahydrofuran; the second solvent includes one of N,N-dimethylformamide, N,N-dimethylacetamide, and dimethyl sulfoxide. In the spinning solution, the mass fraction of polyurethane prepolymer is 35%-45%, and the mass fraction of binary solvent is 55%-65%. In step S2, the emulsion coagulation bath contains an emulsifier with a mass fraction of 0.5%-2%, functional particles with a mass fraction of 0.1%-5%, and the total mass fraction of silicone oil and deionized water is 93%-99.7%. The mass ratio of silicone oil to deionized water is 1:9-5:5; The silicone oil includes one or more of dimethyl silicone oil, diethyl silicone oil, benzyl silicone oil, hydroxyl silicone oil, and methyl hydrogen silicone oil; the emulsifier includes one of sodium dodecyl sulfate, Tween, Triton, tetraethyl silicate, and tris(hydroxymethyl)aminomethane. The stretching ratio is 1-5 times.

2. The method for preparing functionalized microporous elastic fibers according to claim 1, characterized in that, The functional particles include one or a mixture of multiple of the following: conductive carbon black, graphene, carbon nanotubes, titanium dioxide, zirconium dioxide, magnesium oxide, copper oxide, silver nanowires, and boron nitride.

3. The method for preparing functionalized microporous elastic fibers according to claim 1, characterized in that, Step S1 specifically involves placing a pre-set mass of polyurethane prepolymer in a binary solvent, mechanically stirring at 20-30°C for 100-200 min, and then vacuum degassing at 20-30°C to obtain a spinning solution.

4. The method for preparing functionalized microporous elastic fibers according to claim 1, characterized in that, Step S2 is as follows: Mix silicone oil and emulsifier evenly and heat to 80-100℃ to obtain solution A; at the same time, add functional particles to deionized water, disperse ultrasonically, and heat to 80-100℃ to obtain dispersion B; then add dispersion B to solution A, stir mechanically for 10-30 minutes, and finally emulsify for 5-60 minutes to obtain emulsion coagulation bath.

5. A functionalized microporous elastic fiber, characterized in that, It is prepared by the preparation method according to any one of claims 1 to 4.

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