COMPOSITE FIBER AND METHOD FOR MANUFACTURING THE SAME

Abstract

A composite fiber includes a core comprising a MXene polymer fiber with MXene distributed as stacked nanosheets within a first polymer, a first coating layer of benzoic acid-based organic molecules on the MXene polymer fiber, a second polymer in fiber form on the first coating layer, and a second coating layer of a thermoplastic polymer with a thermal strain of about 80 C. or higher. The method for manufacturing the composite fiber involves mixing MXene and a first polymer, depositing a first coating layer, plying and twisting with a second polymer, and applying a second coating layer. The first polymer may include polyacrylonitrile (PAN), and the second polymer may include materials such as nylon or polyethylene terephthalate (PET). The process includes steps such as wet spinning and surface treatment at high temperatures.

Claims

1. A composite fiber comprising: a MXene polymer fiber comprising a first polymer comprising d MXene; a first coating layer on the MXene polymer fiber; a second polymer and disposed on a surface of the first coating layer; and a second coating layer on the first coating layer and the second polymer.

2. The composite fiber of claim 1, wherein the first polymer comprises polyacrylonitrile (PAN).

3. The composite fiber of claim 1, wherein a content of the MXene is about 20 to 40 wt % based on a total weight of the MXene polymer fiber.

4. The composite fiber of claim 1, wherein, in the MXene polymer fiber, the first polymer and the MXene are combined by an electrostatic interaction.

5. The composite fiber of claim 1, wherein the first coating layer comprises benzoic acid-based organic molecules.

6. The composite fiber of claim 1, wherein fineness of the second polymer is about 50 to 100d.

7. The composite fiber of claim 1, wherein the MXene polymer fiber coated with the first coating layer and the second polymer have a structure in which twists are repeated.

8. The composite fiber of claim 1, wherein the second coating layer is a thermoplastic polymer having a thermal strain of about 80 C. or higher and a degree of polymerization of about 1,000 to 1,000,000.

9. The composite fiber of claim 1, wherein, based on a total weight of the composite fiber, the MXene polymer fiber is included in an amount of about 0.5 to 2 wt %, the second polymer is included in an amount of about 96 to 99 wt %, and the second coating layer is included in an amount of about 0.8 to 3.5 wt %.

10. The composite fiber of claim 1, wherein the composite fiber has tensile strength of about 90 MPa or more and elongation of about 17% or more.

11. A composite fiber comprising: a core comprising a MXene polymer fiber, where the MXene is distributed within a first polymer as stacked nanosheets with the first polymer filling spaces between the nanosheets; a first coating layer applied on the MXene polymer fiber, the first coating layer comprising benzoic acid-based organic molecules; a second polymer having a shape of a fiber and disposed on a surface of the first coating layer; and a second coating layer on the first coating layer and the second polymer, the second coating layer comprising a thermoplastic polymer having a thermal strain of about 80 C. or higher and a degree of polymerization of about 1,000 to 1,000,000.

12. The composite fiber of claim 11, the first polymer comprises polyacrylonitrile (PAN), and the second polymer comprises nylon, polyethylene terephthalate (PET), polyethylene (PE), aramid, cotton, polyimide (PI), polyacrylic acid (PAA), or a combination thereof.

13. A method for manufacturing a composite fiber, the method comprising: mixing MXene and a first polymer to obtain a MXene polymer fiber; depositing a first coating layer on the MXene polymer fiber; a plying and twisting operation of plying and twisting the MXene polymer fiber and the second polymer to obtain a ply yarn; and obtaining a second coating layer on the plied yarn.

14. The method of claim 13, wherein the obtaining of the MXene polymer fiber comprises: preparing a first dispersion comprising MXene and a first solvent; preparing a second dispersion comprising a first polymer and a second solvent; obtaining a mixed solution comprising the first dispersion and the second dispersion; and a wet spinning operation of wet spinning the mixed solution to obtain a MXene polymer fiber.

15. The method of claim 14, wherein the first solvent and the second solvent are each independently at least one selected from the group consisting of methylpyrrolidone (1-methyl-2-pyrrolidinone-N-methyl-2-pyrrolidone (NMP)), dimethylformamide (N, N-dimethylformamide (DMF)), dimethylacetamide (DMAc), and dimethyl sulfoxide (DMSO).

16. The method of claim 13, wherein the MXene polymer fiber comprises a substrate comprising a first polymer and having a shape of a fiber and MXene distributed inside the substrate, and comprises about 20 to 40 wt % of the MXene.

17. The method of claim 13, wherein the obtaining of the first coating layer comprises immersing the MXene polymer fiber in a surface treatment solution comprising benzoic acid-based organic molecules.

18. The method of claim 17, wherein the immersing is performed at about 80 C. or higher for about 30 minutes or longer.

19. The method of claim 13, wherein the plying and twisting comprises plying the MXene polymer fiber and the second polymer and then rotating and twisting the entire fiber.

20. The method of claim 13, wherein the obtaining of the second coating layer comprises immersing the plied yarn in a surface treatment solution comprising the second polymer and then performing drying.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0034] The above and other aspects, features, and advantages of the present disclosure will be more clearly understood from the following detailed description, taken in conjunction with the accompanying drawings, in which:

[0035] FIG. 1 is a diagram illustrating a cross-section of a composite fiber according to an embodiment of the present disclosure;

[0036] FIG. 2 is a diagram illustrating an SEM cross-section of a composite fiber according to an embodiment of the present disclosure;

[0037] FIG. 3 is a flowchart illustrating a method for manufacturing a composite fiber, which is an embodiment of the present disclosure;

[0038] FIG. 4 is a graph illustrating the results of heat resistance evaluation of a composite fiber of Example 1 of the present disclosure;

[0039] FIG. 5 is a graph illustrating FT-IR measurement results of the composite fiber of Example 1 of the present disclosure;

[0040] FIG. 6 is a graph illustrating the results of light resistance evaluation of the composite fiber of Example 1 of the present disclosure;

[0041] FIG. 7 is a graph illustrating the results of bending evaluation of the composite fiber of Example 1 of the present disclosure; and

[0042] FIG. 8 is a graph illustrating the results of torsion evaluation of the composite fiber of Example 1 of the present disclosure.

DETAILED DESCRIPTION

[0043] The objects described above, as well as other objects, features, and advantages, will be clearly understood from the following preferred embodiments with reference to the attached drawings. However, the present disclosure is not limited to the embodiments, and may be embodied in different forms. The embodiments are suggested only to offer a thorough and complete understanding of the disclosed context and to sufficiently inform those skilled in the art of the technical concept of the present disclosure.

[0044] Like reference numbers refer to like elements throughout the description of the figures. In the drawings, the sizes of structures may be exaggerated for clarity. It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be construed as being limited by these terms, which are used only to distinguish one element from another. For example, within the scope defined by the present disclosure, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element. Singular forms are intended to include plural forms as well, unless the context clearly indicates otherwise.

[0045] It will be further understood that terms, such as comprise or has, when used in this specification, specify the presence of stated features, integers, steps, operations, elements, components, or combinations thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof. In addition, it will be understood that, when an element, such as a layer, film, region, or substrate is referred to as being on another element, it may be directly on the other element, or an intervening element may also be present. It will also be understood that when an element, such as a layer, film, region, or substrate is referred to as being under another element, it may be directly under the other element, or an intervening element may also be present.

[0046] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used herein, the singular forms a, an and the are intended to include the plural forms as well, unless the context clearly indicates otherwise. These terms are merely intended to distinguish one component from another component, and the terms do not limit the nature, sequence or order of the constituent components. As used herein, the term and/or includes any and all combinations of one or more of the associated listed items. In addition, the terms unit, -er, -or, and module described in the specification mean units for processing at least one function and operation, and can be implemented by hardware components or software components and combinations thereof.

[0047] Although exemplary embodiment is described as using a plurality of units to perform the exemplary process, it is understood that the exemplary processes may also be performed by one or plurality of modules. Additionally, it is understood that the term controller/control unit refers to a hardware device that includes a memory and a processor and is specifically programmed to execute the processes described herein. The memory is configured to store the modules and the processor is specifically configured to execute said modules to perform one or more processes which are described further below.

[0048] Further, the control logic of the present disclosure may be embodied as non-transitory computer readable media on a computer readable medium containing executable program instructions executed by a processor, controller or the like. Examples of computer readable media include, but are not limited to, ROM, RAM, compact disc (CD)-ROMs, magnetic tapes, floppy disks, flash drives, smart cards and optical data storage devices. The computer readable medium can also be distributed in network coupled computer systems so that the computer readable media is stored and executed in a distributed fashion, e.g., by a telematics server or a Controller Area Network (CAN).

[0049] Unless specifically stated or obvious from context, as used herein, the term about is understood as within a range of normal tolerance in the art, for example within 2 standard deviations of the mean. About can be understood as within 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.5%, 0.1%, 0.05%, or 0.01% of the stated value. Unless otherwise clear from the context, all numerical values provided herein are modified by the term about.

[0050] Unless the context clearly indicates otherwise, all numbers, figures, and/or expressions that represent ingredients, reaction conditions, polymer compositions, and amounts of mixtures used in the specification are approximations that reflect various uncertainties of measurement occurring inherently in obtaining these figures, among other things. For this reason, it should be understood that, in all cases, the term about should be understood to modify all such numbers, figures and/or expressions. In addition, when numerical ranges are disclosed in the description, these ranges are continuous, and include all numbers from the minimum to the maximum, including the maximum within each range, unless otherwise defined. Furthermore, when a range refers to an integer, it includes all integers from the minimum to the maximum, including the maximum within the range, unless otherwise defined.

Composite Fiber

[0051] FIG. 1 is a diagram illustrating a cross-section of a composite fiber 100, which is an embodiment of the present disclosure, and FIG. 2 is a diagram illustrating an SEM cross-section of the composite fiber 100, which is an embodiment of the present disclosure.

[0052] Referring to FIG. 1 and/or FIG. 2, the composite fiber 100, which is an embodiment of the present disclosure, includes a MXene polymer fiber 10 including a first polymer having the shape of a fiber and MXene distributed inside the first polymer; a first coating layer 20 coated on the MXene polymer fiber 10; a second polymer 30 having the shape of a fiber and disposed on a surface of the first coating layer 20; and a second coating layer 40 coated on the first coating layer 20 and the second polymer 30.

[0053] MXene is a new two-dimensional material having high electrical conductivity and electrochemical properties similar to metals. MXene has a hydrophilic surface and due to negatively charged functional groups (OH, O, F), MXene has excellent dispersibility and is easy to assemble into a structure. In addition, since MXene does not require post-processing like graphene oxide, the expected cost of the process is low. In the case of fibers manufactured as a structure, electrical and mechanical properties are significantly reduced. The reason why these physical properties are weak is because the MXene is formed of a plurality of stacked nanosheets and has low bonding strength due to pores between nanosheets inside the MXene.

[0054] Therefore, in an embodiment of the present disclosure, in order to solve the weak physical properties of MXene as described above, in the MXene polymer fiber 10, MXene is a plurality of nanosheets being stacked, and the first polymer fills between the nanosheets, and the first polymer fills pores between the nanosheets to have improved physical properties.

[0055] In an embodiment, based on the total weight of the MXene polymer fiber 10, the content of the MXene may be 20 to 40 wt %. If the content of MXene is less than 20 wt %, electrical conductivity may be reduced due to high resistance, and if the content of MXene exceeds 40 wt %, MXene may act as an impurity and cause radioactivity problems, such as fiber breakage when forming a fiber structure.

[0056] The first polymer may include monomers having a nitrile functional group and a polymer polymerized with a monomer having a nitrile functional group. For example, it may be polyacrylonitrile (PAN).

[0057] In the MXene polymer fiber 10, the first polymer and the MXene may be combined by electrostatic interaction.

[0058] In the MXene polymer fiber 10, a hydroxyl group, which is a functional group of the MXene, and the nitrile functional group, which is the functional group of the first polymer, may be combined by electrostatic interaction, thereby increasing the dispersibility of the composite fiber 100.

[0059] The MXene polymer fiber 10 may have a circular, oval, hollow, or flat cross-sectional shape. Specifically, in the present disclosure, the circular and flat types may have an aspect ratio of 1 to 30.

[0060] An embodiment of the present disclosure may include the first coating layer 20 coated on the MXene polymer fiber. The first coating layer 20 may activate the surface of the MXene polymer fiber and provide stability and bonding strength with the second polymer 30 and/or the second coating layer 40, which will be described below.

[0061] The first coating layer 20 may include benzoic acid-based organic molecules and, specifically, may be at least one selected from the group consisting of benzoic acid ester, benzoic acid amide, benzoyl chloride, benzoic acid anhydride, 2-bromobenzoic acid, 3-bromobenzoic acid, 4-bromobenzoic acid, salicylic acid, terephthalic acid, phthalic acid, and the like.

[0062] An embodiment of the present disclosure has the shape of a fiber and may include a second polymer disposed on the surface of the first coating layer 20. The second polymer may provide mechanical strength, elasticity, etc. to the composite fiber 100.

[0063] The fineness of the second polymer may be 50 to 100d. If the fineness of the second polymer is less than 50d, it may be difficult to weave, and if the fineness of the second polymer exceeds 100d, heat generation efficiency of the composite fiber 100 may be reduced.

[0064] The MXene polymer fiber 10 coated with the first coating layer 20 and the second polymer 30 may have a structure in which twists are repeated. The second polymer 30 may be twisted with the MXene polymer fiber 10 coated with the first coating layer 20 to improve elongation and tensile strength of the MXene polymer fiber 10. The twist may be clockwise or counterclockwise and is not particularly limited.

[0065] The second polymer is not particularly limited as long as it is a polymer that may be melt-spun, and the second polymer may be, for example, at least one selected from the group consisting of nylon, polyethylene terephthalate (PET), polyethylene (PE), aramid, cotton, polyimide (PI), polyacrylic acid (PAA), and the like.

[0066] An embodiment of the present disclosure may include the second coating layer 40 coated on the first coating layer 20 and the second polymer 30. The second coating layer 40 may prevent oxidation of the MXene polymer fiber 10, which is vulnerable to moisture, improve bonding strength of the braided yarn, and provide insulation.

[0067] The second coating layer 40 may be a thermoplastic polymer having a thermal strain of 80 C. or higher and a degree of polymerization of 1,000 to 1,000,000, and may be specifically at least one selected from the group consisting of polycarbonate (PC), polyvinylidene fluoride (PVDF), and the like.

[0068] Based on the total weight of the composite fiber 100, the MXene polymer fiber 10 may be included in an amount of 0.5 to 2 wt %, the second polymer 30 may be included in an amount of 96 to 99 wt %, the second coating layer 40 may be included in an amount of 0.8 to 3.5 wt %, and the first coating layer 20 may be included in an amount of 0.01 wt % or less.

[0069] The tensile strength of the composite fiber 100 may be 90 MPa or more, and the elongation may be 17% or more.

[0070] The composite fiber 100 is not particularly limited, but may have a diameter of, for example, 10 to 300 m.

[0071] The composite fiber 100 may be used in various fields, such as fabric, knit, and non-woven heating members.

[0072] The composite fiber 100 may have improved oxidation prevention, durability, elongation, and tensile strength compared to existing MXene fibers, etc., and may have higher stability against external stimuli.

Method for Manufacturing Composite Fiber

[0073] Hereinafter, a method for manufacturing the composite fiber 100 according to the present disclosure is described in detail. In the above manufacturing method, the composite fiber 100 including MXene, the first polymer, the second polymer, the first coating layer 20, and the second coating layer 40 is the same as the composite fiber 100 described above, so a detailed description thereof is omitted.

[0074] FIG. 3 is a flowchart illustrating a method for manufacturing the composite fiber 100, which is an embodiment of the present disclosure. Referring to FIG. 3, the method for manufacturing the composite fiber 100, which is an embodiment of the present disclosure, may include mixing MXene and a first polymer to obtain a MXene polymer fiber (S10); depositing a first coating layer on the MXene polymer fiber 10 (S20); a plying and twisting operation of plying and twisting the MXene polymer fiber 10 and the second polymer to obtain a ply yarn (S30); and obtaining a second coating layer on the plied yarn (S40).

[0075] An embodiment of the present disclosure may include an operation (S10) of obtaining a MXene polymer fiber by mixing MXene and the first polymer. Specifically, the operation (S10) of obtaining the MXene polymer fiber may include preparing a first dispersion including MXene and a first solvent; preparing a second dispersion including a first polymer and a second solvent; obtaining a mixed solution including the first dispersion and the second dispersion; and a wet spinning operation of wet spinning the mixed solution to obtain MXene polymer fiber.

[0076] The first dispersion may have a MXene concentration of 10 to 45 mg/mL. If the concentration of MXene is less than 10 mg/mL, when mixed with the first polymer, a low viscosity mixed solution may be produced and radioactivity may be lowered, and if the concentration of MXene exceeds 45 mg/mL, aggregation of MXene and the first polymer may occur and the viscosity may be very high and therefore radioactivity may be lowered.

[0077] MXene has excellent dispersibility in water because it has hydrophilic functional groups on the surface. However, MXene dispersed in water is difficult to use practically when produced in high concentration. The reason is because MXene is difficult to redisperse in water.

[0078] In addition, it is difficult to prepare a uniform dispersion because nanosheets in MXene tend to agglomerate with each other. Therefore, in the present disclosure, an organic solvent may be used as the first solvent.

[0079] The second dispersion may have a concentration of the first polymer of 50 to 500 mg/mL. If the concentration of the first polymer is less than 50 mg/mL, the mixed solution may not solidify, and if the concentration of the first polymer exceeds 500 mg/mL, uniform spinning may not be achieved due to high conductivity of the mixed solution.

[0080] The first solvent and the second solvent may be independently at least one selected from the group consisting of methylpyrrolidone (1-methyl-2-pyrrolidinone-N-methyl-2-pyrrolidone (NMP)), dimethylformamide (N, N-Dimethylformamide (DMF)), dimethylacetamide (DMAc), dimethyl sulfoxide (DMSO), etc.

[0081] The first polymer may include polyacrylonitrile (PAN), and since polyacrylonitrile is not dispersed in moisture, an organic solvent may be used as the second solvent as described above.

[0082] When an organic solvent is used as a solvent for both the MXene and the first and second dispersions, they are stable at high concentrations, so a uniform mixed solution may be obtained without agglomeration of MXene.

[0083] In addition, MXene dispersed in an organic solvent exhibits high affinity with a polyacrylonitrile solution due to a surface functional group thereof, so a stable mixed solution may be obtained. That is, solution stability is excellent, a high concentration spinning solution may be prepared, and a mixed solution having high oxidation stability may be obtained.

[0084] In the mixed solution, MXene may be included in an amount of 20 to 40 wt % based on the total weight of MXene and the first polymer. If the content of MXene is less than 20 wt %, conductivity may decrease due to an increase in electrical resistance, and if the content of MXene exceeds 40 wt %, it may be impossible to form a gel capable of spinning fiber and spinning may not be possible.

[0085] The wet spinning operation (S10) of obtaining MXene polymer fibers by wet spinning the mixed solution may be an operation of obtaining MXene polymer fibers by wet spinning the mixed solution into a coagulation solution. Specifically, wet spinning in the present disclosure may be, for example, a method in which spinning is performed into a coagulating liquid in which fibers are solidified through a spinneret (nozzle) by applying pressure to a mixed solution so that solidification proceeds by diffusion of a solvent into the coagulating liquid to be leached to form fibers.

[0086] The mixed solution may be spun at a rate of 0.1 to 35 mL/h. If the spinning speed exceeds 35 mL/h, there may be a problem in that non-uniform fibers are spun due to lack of constant shear stress in the mixed solution.

[0087] The coagulating liquid may be at least one selected from the group consisting of water, acetone, methanol, ethyl alcohol, isopropyl alcohol, methyl acetate, ethyl acetate, propyl acetate, acetic acid, acetonitrile, 1-methyl-2-pyrrolidinone-N-methyl-2-pyrrolidone (NMP), dimethylformamide (N, N-dimethylformamide (DMF), dimethylacetamide (DMAc), dimethyl sulfoxide (DMSO), tetrahydrofuran (THF), etc. For example, the coagulating liquid may include water and ethanol in a volume ratio of 3:7 to 7:3.

[0088] A temperature of the coagulating liquid may be 20 C. to 60 C. If the temperature of the coagulating liquid is less than 20 C., a coagulation speed may be slow and irregular shrinkage may occur during a drying process of a remaining solvent, which may deteriorate the physical properties. If the temperature of the coagulating liquid exceeds 60 C., a solvent diffusion rate may increase and the solvent on the surface of the fiber may quickly escape and solidify, so the solvent inside the fiber may remain, which may deteriorate the physical properties thereof.

[0089] The wet spinning may use a spinneret having a diameter of 10 to 1500 m. Specifically, a spinneret having a diameter of 100 to 1000 m, more specifically 100 to 500 m, and even more specifically 100 to 410 m, may be used. If the diameter of the spinneret is less than 10 m, a problem may occur in which spinning through the nozzle may not proceed, and if the diameter of the spinneret exceeds 1500 m, the orientation and density of the fibers may decrease due to insufficient shear stress, which may deteriorate mechanical properties.

[0090] The MXene polymer fiber 10 may be stretched 1 to 20 times. Through the stretching, the degree to which the nanosheets in the MXene and the first polymer are aligned in an axial direction of the fiber, that is, the degree of orientation, may be improved.

[0091] An embodiment of the present disclosure may include depositing a first coating layer on the MXene polymer fiber 10 (S20). The first coating layer 20 may provide plying of the MXene polymer fiber 10, the second polymer and/or the second coating layer 40 stability and bonding strength.

[0092] The operation (S20) of obtaining the first coating layer may be an operation of immersion in a surface treatment solution including benzoic acid-based organic molecules. The benzoic acid-based organic molecules may be the same as the organic molecules described above.

[0093] The immersion operation may be performed at 80 to 150 C. for 30 minutes or more. In the aforementioned range, the benzoic acid-based organic molecules may be easily coated on the MXene polymer fiber 10.

[0094] The MXene polymer fiber 10 on which the first coating layer 20 is formed may be surface treated to be hydrophilic, thereby increasing the bonding strength with the second polymer 30 and/or the second coating layer 40.

[0095] An embodiment of the present disclosure may include a plying and twisting operation (S30) of plying and twisting the MXene polymer fiber 10 and the second polymer to obtain a plied yarn. The MXene polymer fiber 10 may be a fiber on which the first coating layer 20 is formed. The elongation and tensile strength of the MXene polymer fiber 10 may be improved by plying the MXene polymer fiber 10 and the second polymer and then twisting them.

[0096] The plying and twisting operation (S30) may include plying the MXene polymer fiber 10 and the second polymer, then rotating and twisting the entire fiber. If the MXene polymer fiber 10 and the second polymer are not plied, manufacturing time, costs, etc. may increase and it may be difficult to improve the elongation of the MXene polymer fiber 10, and if the MXene polymer fiber 10 and the second polymer are not twisted, the elongation of the manufactured composite fiber 100 may be insufficient and a short circuit of the MXene polymer fiber 10 may occur.

[0097] In the plying and twisting operation (S30), a twisting speed may be greater than 0 and less than or equal to 100 RPM. If the twisting speed is 0 RPM, twisting may not proceed, and if the twisting speed exceeds 100 RPM, breakage of the fiber may occur.

[0098] According to the plying and twisting operation (S30), a weight ratio of the MXene polymer fiber 10 and the second polymer may be 0.5 to 2:96 to 99 with respect to the total content of the plied yarn. If the content ratio of the MXene polymer fiber 10 is less than the aforementioned weight ratio, the heat generation performance of the composite fiber 100 may be inferior, and if the content ratio of the MXene polymer fiber 10 exceeds the above range, the mechanical strength and elasticity of the composite fiber 100 may be inferior.

[0099] An embodiment of the present disclosure may include obtaining a second coating layer on the plied yarn (S40). The second coating layer 40 may prevent oxidation of the MXene polymer fiber 10 due to moisture, etc., and may provide bonding strength and insulation to the braided yarn in the plying and twisting operation (S30).

[0100] The operation (S40) of obtaining the second coating layer may be an operation of immersing the plied yarn in the surface treatment solution including the second polymer and then drying the same. Drying conditions are not particularly limited, but for example, drying may be performed at 100 to 200 C. for about 1 to 60 seconds.

[0101] The plying and twisting operation (S30) and the operation (S40) of obtaining the second coating layer may be performed simultaneously. For example, the plied yarn may be twisted as it is introduced into a guide rod, and at the same time, a raw material for the second coating layer 40 may be fed to immerse the plied yarn inside the guide rod.

[0102] The composite fiber manufactured according to the method for manufacturing the composite fiber 100, which is an embodiment of the present disclosure, may have improved oxidation prevention, durability, elongation, and tensile strength of MXene and may have high stability against external stimuli.

EXAMPLE

[0103] Hereinafter, Examples of an embodiment is described in detail. The following Examples are intended to describe an embodiment in more detail and are not intended to limit the embodiment.

Manufacturing Example

1. Example 1

(1) Manufacturing of MXene Polymer Fiber

[0104] A first dispersion including MXene and dimethyl sulfoxide at a concentration of 9.09 mg/mL and a second dispersion including polyacrylonitrile and dimethyl sulfoxide at a concentration of 100 mg/mL were mixed to produce a mixed solution having a weight ratio of MXene and polyacrylonitrile 3:7 was prepared.

[0105] The mixed solution was introduced into a plastic syringe equipped with a spinneret having a diameter of 100 m, and spun into a coagulation bath at a rate of 15 mL/h using an injection pump to obtain MXene polymer fibers having a fineness of 1d. At this time, the temperature of a coagulating liquid in the coagulation bath was 20 C., and the liquid was a mixed liquid of water and ethanol in a volume ratio of 3:7. The obtained MXene polymer fiber was dried through a drying heater at 60 C. and further dried at 80 C. for heat fixation.

(2) Manufacturing of Composite Fiber

[0106] The prepared MXene polymer fiber was immersed in a mixed solution of 4-aminobenzoic acid and urea at 120 C. for about 30 minutes to prepare a MXene polymer fiber having a first coating layer.

[0107] The prepared MXene polymer fiber and PET having a fineness of 50d at a weight ratio of 2:98 as a second polymer, were plied and then all fibers were rotated and twisted to produce a plied yarn.

[0108] After immersing the plied yarn in a polyvinylidene fluoride (PVDF) solution at 120 C. for about 30 minutes, the PVDF solution including 10 wt % of butyl alcohol was fed to a T-shaped tube maintained at 50 C. at 0.5 mL/s, and the plied yarn was allowed to pass at 3 cm/s and dried at 130 C. for 10 seconds to prepare a composite fiber having the second coating layer, which is illustrated in Table 1 below.

2. Example 2

[0109] A composite fiber was manufactured in the same manner as Example 1, except that the fineness of the second polymer was changed to 100d in Example 1, which is illustrated in Table 1 below.

3. Example 3

[0110] A composite fiber was manufactured in the same manner as Example 1, except that the second polymer was changed to nylon in Example 1, which is illustrated in Table 1 below.

4. Example 4

[0111] A composite fiber was manufactured in the same manner as Example 1, except that the material of the second coating layer was changed to polycarbonate (PC) in Example 1, which is illustrated in Table 1 below.

5. Comparative Example 1

[0112] A composite fiber was manufactured in the same manner as Example 1, except that the first coating layer was not prepared in Example 1, which is illustrated in Table 1 below.

6. Comparative Example 2

[0113] A composite fiber was manufactured in the same manner as Example 1, except that the composite fiber was coated with hydrochloric acid (HCl) as a first coating layer solution in Example 1, which is illustrated in Table 1 below.

7. Comparative Example 3

[0114] A composite fiber was manufactured in the same manner as Example 1, except that plying and twisting with the second polymer were not performed in Example 1, which is illustrated in Table 1 below.

8. Comparative Example 4

[0115] A composite fiber was manufactured in the same manner as Example 1, except that twisting with the second polymer was not performed, which is illustrated in Table 1 below.

9. Comparative Example 5

[0116] A composite fiber was manufactured in the same manner as Example 1, except that the second coating layer was not prepared, which is illustrated in Table 1 below.

10. Comparative Example 6

[0117] Fibers that did not undergo additional processing in the MXene polymer fibers prepared in Example 1 were made into composite fibers, which is illustrated in Table 1 below.

11. Comparative Example 7

[0118] Using a silkscreen process, the composite fibers of Comparative Example 6 were introduced on a polyimide (PI) film and then covered with the PI film again to manufacture composite fibers.

TABLE-US-00001 TABLE 1 Type of Fineness (d) Type of Type of first second of second Plying/ second coating layer polymer polymer twisting coating layer Example 1 4-aminobenzoic PET 50 PVDF acid Example 2 4-aminobenzoic PET 100 PVDF acid Example 3 4-aminobenzoic Nylon 50 PVDF acid Example 4 4-aminobenzoic PET 50 PC acid Comparative PET 30~50 PVDF Example 1 Comparative HCl PET 30~50 PVDF Example 2 Comparative 4-aminobenzoic PVDF Example 3 acid Comparative 4-aminobenzoic PET 30~50 X PVDF Example 4 acid Comparative 4-aminobenzoic PET 50 Example 5 acid Comparative X Example 6 Comparative X Example 7

Evaluation Example

1. Measurement of Chemical Changes

[0119] The composite fibers of Examples 1 to 4 and Comparative Examples 1 to 7 were evaluated for heat resistance, light resistance, and moisture resistance, and a case in which there was no abnormality in any of the evaluations in Table 2 below was recorded as no abnormality.

(1) Evaluation of Heat Resistance

[0120] Using MS 210-05, each of the composite fibers of Examples 1 to 4 and Comparative Examples 1 to 7 was exposed to a total of 3 cycles of 100 C. for 3 hours, 40 C. for 3 hours, and 50 C. for 7 hours. Thereafter, the heat generation performance was measured, which is illustrated in Table 2 below.

[0121] In addition, the measurement results of evaluation of heat resistance of the composite fiber of Example 1 are illustrated in FIG. 4. In addition, the composite fiber of Example 1 was measured by FT-IR to determine whether there was a change in the chemical structure, which are illustrated in FIG. 5.

(2) Evaluation of Lightfastness

[0122] The heat generation performance of the composite fibers of Examples 1 to 4 and Comparative Examples 1 to 7 was measured before UV exposure, after exposure to 42 MJ of UV, and after exposure to 84 MJ, which is illustrated in Table 2 below.

[0123] In addition, the measurement results of evaluation of heat resistance of the composite fiber of Example 1 are illustrated in FIG. 6.

(3) Evaluation of Moisture Resistance

[0124] The condition of the composite fibers of Examples 1 to 4 and Comparative Examples 1 to 7 was measured after being placed in a chamber at 50 C. and 95% relative humidity for one day, which is illustrated in Table 2 below.

2. Measurement of Physical Changes

[0125] The composite fibers of Examples 1 to 4 and Comparative Examples 1 to 7 were evaluated for bending and torsion properties, and a case in which there was no abnormality in even one evaluation in Table 2 below was indicated as no abnormality.

(1) Evaluation of Bending

[0126] Both ends of the yarn were fixed such that one end of each of the composite fibers of Examples 1 to 4 and Comparative Examples 1 to 7 was fixed the other end thereof was fixed to a device capable of moving left and right at a constant speed.

[0127] Thereafter, a cycle was performed in which each composite fiber was rotated 1000 times at angles of 90 and 180, and in order to evaluate a short circuit of the composite fiber, electrical resistance was measured. A case in which the electrical resistance was measured to be the same as an initial state was indicated as X and a case in which the electrical resistance was not measured to be the same as the initial state was indicated as O in Table 2 below.

[0128] In addition, the measurement results of evaluation of bending of the composite fiber of Example 1 are illustrated in FIG. 7.

(2) Evaluation of Torsion

[0129] Both ends of the yarn were fixed such that one end of each of the composite fibers of Examples 1 to 4 and Comparative Examples 1 to 7 was fixed the other end thereof was fixed to a device capable of moving left and right at a constant speed.

[0130] Thereafter, in an environment in which no tension was applied to the fabric and yarn, they were rotated at 90, 180, 270, 360, and 720, and to evaluate a short circuit of the composite fiber, electrical resistance was measured. A case in which the electrical resistance was measured to be the same as an initial state was indicated as X and a case in which the electrical resistance was not measured to be the same as the initial state was indicated as O in Table 2 below.

[0131] In addition, the measurement results of evaluation of torsion of the composite fiber of Example 1 are illustrated in FIG. 8.

3. Evaluation of Feasibility of Weaving

[0132] The composite fibers of Examples 1 to 4 and Comparative Examples 1 to 7 were stretched at a constant rate using MS300-32 to evaluate tensile strength and elongation at the time of fracture.

[0133] Based on the above measurement results, a case in which the composite fiber had a tensile strength of 95 MPa or more and an elongation of 17% or more was evaluated as feasibility of weaving, and a case in which the composite fiber had a tensile strength less than 95 MPa or the elongation less than 17% was evaluated as infeasibility of weaving.

4. Evaluation of Heat Generation Efficiency

[0134] According to a radiant heat warmer parts test method, an IR camera was installed at a distance of about 7 cm from a heating portion formed of the composite fibers of Examples 1 to 4 and Comparative Examples 1 to 7, and a power amount and time for the heating portion to rise to a reference temperature were measured. was measured, and a (heat generation efficiency of composite fiber/heat generation efficiency of copper wire) values, compared to the heat generation efficiency of the heating portion formed of copper wire are illustrated in Table 2 below.

TABLE-US-00002 TABLE 2 Chemical Feasibility Heat generation efficiency change Physical change of weaving (compared to copper wire) Example 1 no abnormality no abnormality 65 times Example 2 no abnormality no abnormality 65 times Example 3 no abnormality no abnormality 65 times Example 4 no abnormality no abnormality 65 times Comparative Oxidized Separation of X impossible to measure Example 1 coating layer Comparative Impossible to Impossible to X impossible to measure Example 2 manufacture manufacture Comparative no abnormality fiber short- X impossible to measure Example 3 circuit Comparative no abnormality fiber short- X impossible to measure Example 4 circuit Comparative oxidized fiber short- X impossible to measure Example 5 circuit Comparative oxidized fiber short- X impossible to measure Example 6 circuit Comparative no abnormality no abnormality X impossible to measure Example 7

[0135] Referring to Table 2, it can be seen that the composite fibers of Examples 1 to 4 have no chemical or physical changes, are feasible for weaving, and have excellent heat generation efficiency. Referring to FIG. 4, it can be seen that the composite fiber of Example 1, which is an embodiment of the present disclosure, has almost the same heat generation efficiency even after exposure to a heat resistance cycle, exhibiting excellent heat resistance.

[0136] Referring to FIG. 5, the composite fiber of Example 1, which is an embodiment of the present disclosure, has substantially the same FR-IR evaluation results for blue at 0 cycle, red at 1 cycle, and black at 3 cycle, confirming that the chemical structure was not changed.

[0137] Referring to FIG. 6, it can be seen that the composite fiber of Example 1, which is an embodiment of the present disclosure, has almost the same heat generation efficiency even after exposure to the light resistance cycle, confirming excellent light fastness.

[0138] Referring to FIG. 7, it can be seen that the composite fiber of Example 1, which is an embodiment of the present disclosure, has almost the same heat generation efficiency in the bending evaluation, confirming excellent bendability.

[0139] Referring to FIG. 8, it can be seen that the composite fiber of Example 1, which is an embodiment of the present disclosure, has almost the same heat generation efficiency even in the torsion evaluation, confirming excellent torsion properties.

[0140] Meanwhile, referring to Table 2, it can be seen that the composite fibers of Comparative Examples 1 to 7 had significant chemical and physical changes, so they were not feasible to weaving, so the heat generation efficiency was not able to be evaluated.

[0141] Specifically, in Comparative Example 1, which does not include a first coating layer, the composite fiber was oxidized in a chemical change evaluation and the polymer layer was peeled off due to a low interface, confirming that it is not feasible to weaving. In Comparative Example 2, in which acid (HCl) treatment was performed, it can be seen that the fibers expanded due to acid treatment, making weaving impossible. Comparative Examples 3 and 4, in which no plying and twisting were performed or no twisting was performed, had excellent chemical evaluations, but were not feasible to weaving due to poor bending and torsion properties. In Comparative Example 5, in which the second polymer coating treatment was not performed, MXene was oxidized and the fibers were short-circuited, making weaving impossible. In Comparative Example 6, which is the MXene polymer fiber itself, it can be seen that MXene was oxidized and the fibers were short-circuited, making weaving impossible. Comparative Example 6, a heating element manufactured in Comparative Example 6, has no chemical structural changes, but is difficult to weave.

[0142] The composite fiber, which is an embodiment of the present disclosure, may have improved oxidation prevention and durability.

[0143] The composite fiber, which is an embodiment of the present disclosure, may have improved elongation and tensile strength.

[0144] The composite fiber, which is an embodiment of the present disclosure, may have high stability against external stimuli.

[0145] The composite fiber manufactured according to the method for manufacturing a composite fiber, which is an embodiment of the present disclosure, may have improved oxidation prevention, durability, elongation, and tensile strength of MXene and may have high stability against external stimuli.

[0146] While example embodiments have been illustrated and described above, it will be apparent to those skilled in the art that modifications and variations could be made without departing from the scope of the present disclosure as defined by the appended claims.