Functional fiber embedded with boron nitride nanosheet and preparation method and application thereof

Abstract

The application relates to the technical field of fiber materials, and discloses a functional fiber embedded with boron nitride nanosheets as well as a preparation method and application of the functional fiber. The preparation method comprises the following steps: S1, dopamine-modified hexagonal boron nitride nanosheets; S2, the dopamine-modified hexagonal boron nitride nanosheets are dissolved in a bacterial cellulose solution, uniformly mixed, and then a wet spinning method is adopted to obtain the functional fiber, wherein the extrusion speed of the wet spinning method is 3 mL / h, and the pre-stretching winding speed is 0.1 r / min-0.9 r / min. The preparation method finally obtains the functional fiber, and through the design between the method steps, a fiber with high thermal conductivity and flexibility is obtained.

Description

Technical Field

[0001] This invention relates to the field of fiber materials technology, and in particular to a functional fiber with embedded boron nitride nanosheets, its preparation method, and its application. Background Technology

[0002] The textile industry is a pillar industry of my country's national economy and social development, a fundamental industry for addressing people's livelihood and beautifying life, and an advantageous industry for international cooperation and integrated development. However, my country's textile industry faces challenges such as a high proportion of low value-added products, resource and environmental pressures, rising labor costs, and insufficient innovation capabilities. The deepening of international regional investment and trade agreements is promoting the transfer of capital markets to labor-intensive regions such as Southeast Asia and South Asia, further altering the global investment and trade landscape of the textile industry. Currently, my country's textile industry faces unprecedented pressure and challenges. Transforming traditional textiles into high-tech functional textiles and intelligent textiles is a crucial development path to address these issues.

[0003] With the rapid development of the textile industry, people have placed higher demands on the fabric products they wear. The perceived warmth or coolness of fabric upon contact with human skin, which is the brain's perception of cold and heat based on the temperature stimulus emitted by the fabric, is a crucial indicator of thermal comfort. There are two main commercial technological approaches to achieving this: one is to alter the thermal conductivity of fibers, and the other is to indirectly change the specific heat capacity of the fabric by coating the surface with moisture-absorbing and heat-absorbing substances. However, currently, the process of altering the thermal conductivity of fibers is complex and costly. Inappropriate methods may not only result in poor fiber flexibility but also an increase in fiber diameter, ultimately preventing further weaving and processing, and thus hindering the formation of fabrics. Existing technologies include the use of boron nitride for modification; however, due to boron nitride's poor hydrophilicity and multilayered structure, the bonding between boron nitride and fibers becomes more difficult, leading to increased fiber diameter and poor flexibility.

[0004] In the midst of a new round of technological revolution, materials science and technology occupy a leading position, and the task of structural adjustment and industrial upgrading of fiber new materials characterized by high performance, multifunctionality, lightweight and flexibility is becoming increasingly urgent. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a functional fiber embedded with boron nitride nanosheets, its preparation method, and its application. The fiber of this invention not only possesses good flexibility but also high thermal conductivity.

[0006] This invention provides a method for preparing functional fibers embedded with boron nitride nanosheets, the method comprising the following steps:

[0007] S1. Obtaining dopamine-modified boron nitride nanosheets: Hexagonal boron nitride nanosheets were sintered in air at 800℃ for 1 hour. 30g of the sintered hexagonal boron nitride nanosheets were placed in a mixed solution, and the mixed solution was subjected to a hydrothermal reaction at 180℃ for 2 hours to obtain a paste. This paste was then ball-milled using zirconia balls with diameters of 1mm and 10mm, wherein the mass ratio of the 1mm and 10mm zirconia balls was 1:1. The mass ratio of the substance to zirconia spheres was 1:2, and the mixture was sonicated at 100 kHz for 30 min, centrifuged, and washed to obtain boron nitride nanosheets. The boron nitride nanosheets were dispersed in a dopamine solution, the pH of the dopamine solution was adjusted to 8, the concentration of the dopamine solution was 0.5 g / 200 mL, and the concentration of the boron nitride nanosheets in the dopamine solution was 1 g / 200 mL. Modification was carried out at room temperature to obtain dopamine-modified boron nitride nanosheets (PDA-BNNS).

[0008] S2: Dopamine-modified boron nitride nanosheets are dissolved in a bacterial cellulose (BC) solution, with the mass percentage of dopamine-modified boron nitride nanosheets in the bacterial cellulose solution being 50%. After uniform mixing, functional fibers are obtained by wet spinning, wherein the extrusion speed of the wet spinning method is 3 mL / h, the pre-stretching winding speed is 0.1 r / min-0.9 r / min, and the fibers are air-dried to obtain the functional fibers of the present invention.

[0009] Furthermore, the preparation process of the mixed solution in S1 involves dissolving sodium hydroxide and lithium chloride in deionized water.

[0010] Furthermore, the concentration of sodium hydroxide in the mixed solution is 6.66 g / L.

[0011] Furthermore, the concentration of lithium chloride in the mixed solution is 3.34 g / L.

[0012] Furthermore, the concentration of the 30g hexagonal boron nitride nanosheets sintered in S1 in the mixed solution is 30g / L.

[0013] Furthermore, the ball mill rotates at 500 rpm and the milling time is 4.5-5.5 hours.

[0014] Furthermore, in S1, the centrifugation speed is 1500rpm-2500rpm, and the centrifugation time is 3h-8h.

[0015] Furthermore, the washing includes rinsing with distilled water at least three times.

[0016] Those skilled in the art should understand that repeating the centrifugation and washing steps can help to fully obtain the boron nitride nanosheets in this experiment and improve the yield of boron nitride nanosheets.

[0017] Furthermore, the preparation process of the dopamine solution involves dissolving dopamine in deionized water.

[0018] Furthermore, the solution used to adjust the pH of the dopamine solution to 8 in S1 is tris(hydroxymethyl)aminomethane.

[0019] Furthermore, the modification step in S1 at room temperature is as follows: at 25°C, the dopamine solution containing boron nitride nanosheets is stirred at a speed of 400 rpm-600 rpm for 2.5 h-3 h.

[0020] Furthermore, after modification at room temperature, step S1 also includes filtering, washing, and drying the dopamine-modified boron nitride nanosheets.

[0021] Furthermore, the filtration can be performed using a PVDF (polyvinylidene fluoride) filter membrane.

[0022] Furthermore, the cleaning process includes rinsing with deionized water at least three times.

[0023] Furthermore, the drying temperature is 45℃-55℃, and the drying time is 10h-14h.

[0024] Furthermore, the preparation process of the bacterial cellulose solution includes: adding the dried bacterial cellulose to an N,N-dimethylacetamide solution containing lithium chloride, mixing evenly, and removing air bubbles.

[0025] Furthermore, the bacterial cellulose is present in a 2% mass ratio in an N,N-dimethylacetamide solution containing lithium chloride.

[0026] Furthermore, the mass ratio of lithium chloride in the N,N-dimethylacetamide solution containing lithium chloride is 8%.

[0027] Furthermore, the N,N-dimethylacetamide solution is prepared by dissolving N,N-dimethylacetamide in deionized water, with a volume ratio of N,N-dimethylacetamide to deionized water of 1:2.

[0028] Furthermore, the uniform mixing can be achieved by stirring. As an example, the stirring speed is 1000 rpm and the stirring time is 12 hours. Those skilled in the art can adjust the stirring speed and time according to the actual situation.

[0029] Furthermore, the removal of air bubbles can be achieved by allowing the mixture to stand for at least 12 hours.

[0030] Furthermore, the step of mixing evenly in S2 includes sonication and stirring.

[0031] Furthermore, the ultrasound duration is 25-35 minutes.

[0032] Furthermore, the stirring time is 5-7 hours, and the stirring temperature is 70-90℃.

[0033] The present invention also provides a method for preparing functional fibers with embedded boron nitride nanosheets to obtain functional fibers.

[0034] The present invention also provides the application of the functional fibers prepared by the method for preparing the aforementioned boron nitride nanosheets in fabrics.

[0035] The embodiments of the present invention have the following technical effects:

[0036] 1. The functional fibers obtained by this invention have good flexibility and thermal conductivity. These fibers can be successfully applied to fabrics, resulting in fabrics with high thermal conductivity. The method of this invention enables fiber functionalization and overcomes the technical problems of fiber thickening and decreased flexibility caused by functionalization. Specifically, it includes the following: First, by controlling the sintering temperature of hexagonal boron nitride nanosheets, the selection of the sintering temperature needs to consider the degree of oxidation of the hexagonal boron nitride nanosheets. On the one hand, the hexagonal boron nitride nanosheets need to be oxidized and then peeled off, which is beneficial for obtaining thinner boron nitride nanosheets. On the other hand, if the oxidation is excessive, it will cause the boron nitride nanosheets to break during subsequent peeling, which will not only affect the dopamine loading but also the final fiber flexibility. Based on the above, in this invention, sintering at 800℃ for 1 hour is used for the oxidation treatment.

[0037] To achieve better and more complete exfoliation of oxidized hexagonal boron nitride nanosheets, a staged exfoliation process involving hydrothermal reaction and ball milling was chosen. To control the degree of exfoliation, the added mass of hexagonal boron nitride nanosheets in the hydrothermal reaction was initially controlled at 30g, which facilitated the small-scale exfoliation of hexagonal boron nitride nanosheets in the first stage. During the ball milling process, the ball diameter and ball-to-material ratio were further optimized. Choosing ball diameters of 1mm and 10mm not only further exfoliated the hexagonal boron nitride nanosheets based on the hydrothermal reaction but also increased the lateral dimensions of the boron nitride, thus benefiting dopamine loading. This staged exfoliation process not only ensured the integrity of the hexagonal boron nitride nanosheet morphology and reduced breakage but also achieved a reduction in the final thickness of the boron nitride nanosheets. Ultrasonic treatment after ball milling further dispersed the material and ensured the complete exfoliation of any remaining incompletely exfoliated hexagonal boron nitride nanosheets. Considering that the hydrothermal reaction and ball milling have already carried out two exfoliation processes, 100 kHz ultrasound was used to ensure that the final boron nitride nanosheets have a complete morphology and a small thickness.

[0038] The above method yields thin, well-formed boron nitride nanosheets with a large lateral dimension. This reduces the risk of uneven dopamine deposition due to nanosheet breakage. On one hand, this prevents effective improvement of the hydrophilicity of the boron nitride nanosheets, hindering their integration with bacterial cellulose. On the other hand, uneven dopamine deposition can lead to larger boron nitride nanosheets, resulting in larger fiber diameters and affecting fabric formation. Therefore, the boron nitride nanosheets obtained in this invention achieve uniform and effective dopamine loading.

[0039] Based on this, the amount of boron nitride nanosheets and dopamine added was further adjusted so that the thickness of the modified boron nitride nanosheets could be further controlled on the basis of effective improvement by dopamine. In this invention, the concentration of boron nitride nanosheets in the dopamine solution was selected to be 1g / 200mL.

[0040] Finally, functional fibers were obtained by wet spinning dopamine-modified boron nitride nanosheets with bacterial cellulose. By adjusting the extrusion speed to 3 mL / h and the pre-stretching winding speed to 0.1 r / min-0.9 r / min, the boron nitride nanosheets were aligned along the axial direction to form an ordered structure. The gaps between the fibers and the dopamine-modified boron nitride nanosheets were reduced, which not only improved the flexibility of the fibers and gave them higher mechanical properties, but also further controlled the diameter of the final fibers.

[0041] In summary, the preparation method of the present invention ultimately yields functional fibers. Through the design of the steps in the method, a fiber with high thermal conductivity and flexibility is obtained.

[0042] 2. The method of the present invention is easy to implement and can be industrialized. Attached Figure Description

[0043] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0044] Figure 1 These are test result diagrams of embodiments and comparative examples of the present invention, wherein... Figure 1 (a) is an FTIR analysis. Figure 1 (b) is the Raman spectrum. Figure 1 (c) is XPS analysis. Figure 1 (d) is an XPS scan.

[0045] Figure 2 These are test result diagrams of embodiments and comparative examples of the present invention, wherein... Figure 2 (a) is the Raman spectrum. Figure 2 (b) is an FTIR analysis. Figure 2 (c) is the TG analysis chart. Figure 2 (d) is the XRD pattern.

[0046] Figure 3 These are electron microscope images of embodiments and comparative examples of the present invention, wherein... Figure 3 (a) is an electron microscope image of Comparative Example 5. Figure 3 (b) is an electron microscope image of Comparative Example 7. Figure 3 Image (c) is an electron microscope image of Example 1. Figure 3 The image in (d) is an electron microscope image of Comparative Example 5. Figure 3 (e) is an electron microscope image of Scale 7. Figure 3 Image (f) is an electron microscope image of Example 1.

[0047] Figure 4 These are electron microscope images of the morphological structure characterization of embodiments of the present invention, wherein... Figure 4 Image (a) is an electron microscope image of Example 2. Figure 4 (b) is an electron microscope image of Example 1. Figure 4 Image (c) is an electron microscope image of Example 4. Figure 4 Image (d) is an electron microscope image of Example 2. Figure 4Image (e) is an electron microscope image of Example 1. Figure 4 Image (f) is an electron microscope image of Example 4.

[0048] Figure 5 These are orientation changes in the embodiments and comparative examples of the present invention, wherein Figure 5 In (a), the orientation changes under different states are shown. Figure 5 (b) shows the orientation change at different winding speeds.

[0049] Figure 6 These are electron microscope images of embodiments and comparative examples of the present invention, wherein... Figure 6 (a) is an electron microscope image of Scale 8. Figure 6 (b) is an electron microscope image of Scale 9. Figure 6 Image (c) is an electron microscope image of Example 1. Figure 6 The image in (d) is an electron microscope image of Scale 8. Figure 6 (e) is an electron microscope image of Scale 9. Figure 6 Image (f) is an electron microscope image of Example 1.

[0050] Figure 7 These are thermal conductivity tests of embodiments and comparative examples of the present invention, wherein... Figure 7 In figure (a), the axial thermal conductivity varies with the draw ratio. Figure 7 Figure (b) shows the relationship between winding speed and the thermal conductivity of textiles. Figure 7 (c) is an optical image. Figure 7 (d) is an infrared image.

[0051] Figure 8 These are the thermal conductivity test results of the embodiments and comparative examples of the present invention, wherein... Figure 8 Image (a) shows a physical image of an LED lamp used for testing its heat transfer capacity. Figure 8 (b) is a schematic diagram of the heat transfer capacity test model of the hot plate. Figure 8 Image (c) is an infrared thermal image. Figure 8 The middle (d) graph is the surface temperature profile of the LED lamp. Figure 8 (e) is the fabric surface temperature curve. Figure 8 Image (f) is an infrared thermal image of the LED lamp surface. Detailed Implementation

[0052] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0053] In a first aspect, some embodiments of the present invention provide a method for preparing functional fibers embedded with boron nitride nanosheets, the method comprising the following steps:

[0054] S1. Obtaining Dopamine-Modified Boron Nitride Nanosheets: Hexagonal boron nitride nanosheets were sintered in air at 800℃ for 1 hour. 30g of the sintered hexagonal boron nitride nanosheets were placed in a mixed solution, and the mixed solution was subjected to a hydrothermal reaction at 180℃ for 2 hours to obtain a paste. The paste was ball-milled using zirconia balls with diameters of 1mm and 10mm, wherein the ratio of 1mm to 10mm zirconia balls was 1:1, and the mass ratio of the paste to the zirconia balls was 1:2. The paste was then sonicated at 100kHz for 30 minutes, centrifuged, and washed to obtain boron nitride nanosheets. The boron nitride nanosheets were dispersed in a dopamine solution and modified at room temperature. The pH of the dopamine solution was adjusted to 8, the concentration of the dopamine solution was 0.5g / 200mL, and the concentration of the boron nitride nanosheets in the dopamine solution was 1g / 200mL to obtain dopamine-modified boron nitride nanosheets.

[0055] S2: Dopamine-modified boron nitride nanosheets are dissolved in a bacterial cellulose solution, with the mass ratio of dopamine-modified boron nitride nanosheets in the bacterial cellulose solution being 50%. After uniform mixing, functional fibers are obtained by wet spinning, wherein the extrusion speed of the wet spinning method is 3 mL / h and the pre-stretching winding speed is 0.1 r / min-0.9 r / min.

[0056] In this invention, a boron nitride nanosheet with fewer layers and larger size is prepared through a staged exfoliation process by combining sintering, hydrothermal treatment, ball milling, ultrasonication, dopamine modification, and wet spinning with bacterial cellulose. By modifying the fiber with dopamine, the technical problems in the prior art, such as the increase in fiber volume due to modification leading to a decrease in fiber flexibility, are overcome. Finally, fibers with high thermal conductivity and good flexibility are obtained.

[0057] In some embodiments, the preparation process of the mixed solution in S1 involves dissolving sodium hydroxide and lithium chloride in deionized water.

[0058] In some embodiments, the concentration of sodium hydroxide in the mixed solution is 6.66 g / L.

[0059] In some embodiments, the concentration of lithium chloride in the mixed solution is 3.34 g / L.

[0060] In some embodiments, the concentration of the 30g hexagonal boron nitride nanosheets sintered in S1 in the mixed solution is 30g / L.

[0061] In some embodiments, the ball mill rotates at 500 rpm and the milling time is 4.5-5.5 hours.

[0062] In some embodiments, the centrifugation speed is 1500 rpm-2500 rpm, and the centrifugation time is 3 h-8 h.

[0063] In some embodiments, the washing includes rinsing with distilled water at least three times.

[0064] In some embodiments, the preparation process of the dopamine solution involves dissolving dopamine in deionized water.

[0065] In some embodiments, the solution used to adjust the pH of the dopamine solution to 8 in S1 is tris(hydroxymethyl)aminomethane.

[0066] In some embodiments, the modification step in S1 at room temperature is as follows: at 25°C, the dopamine solution containing boron nitride nanosheets is stirred at a speed of 400 rpm to 600 rpm for 50 min to 70 min.

[0067] In some embodiments, after modification at room temperature in step S1, the process further includes filtering, washing, and drying the dopamine-modified boron nitride nanosheets.

[0068] In some embodiments, the filtration may be performed using a PVDF filter membrane.

[0069] In some embodiments, the cleaning includes rinsing with deionized water at least three times.

[0070] In some embodiments, the drying temperature is 45°C-55°C, and the drying time is 10h-14h.

[0071] In some embodiments, the preparation process of the bacterial cellulose solution includes: adding dried bacterial cellulose to an N,N-dimethylacetamide solution containing lithium chloride, mixing thoroughly, and removing air bubbles.

[0072] In some embodiments, the bacterial cellulose is in a 2% mass ratio in an N,N-dimethylacetamide solution containing lithium chloride.

[0073] In some embodiments, the mass ratio of lithium chloride in the N,N-dimethylacetamide solution containing lithium chloride is 8%.

[0074] In some embodiments, the N,N-dimethylacetamide solution is prepared by dissolving N,N-dimethylacetamide in deionized water, with a volume ratio of N,N-dimethylacetamide to deionized water of 1:2.

[0075] In some embodiments, the uniform mixing can be achieved by stirring. As an example, the stirring speed is 1000 rpm and the stirring time is 12 hours. Those skilled in the art can adjust the stirring speed and time according to the actual situation.

[0076] In some embodiments, the removal of air bubbles can be achieved by allowing the air to stand for at least 12 hours.

[0077] In some embodiments, the step of mixing uniformly in S2 includes sonication and stirring.

[0078] In some embodiments, the ultrasound duration is 25-35 minutes.

[0079] In some embodiments, the stirring time is 5-7 hours, and the stirring temperature is 70-90°C.

[0080] Secondly, some embodiments also provide the method for preparing the functional fibers with embedded boron nitride nanosheets to obtain the functional fibers.

[0081] Thirdly, some embodiments also provide the application of the preparation method of the functional fiber with embedded boron nitride nanosheets in the preparation of functional fibers.

[0082] The following description, in conjunction with specific embodiments, provides further details.

[0083] Example 1:

[0084] Hexagonal boron nitride nanosheets were sintered in air at 800°C for 1 hour. 30 g of the sintered hBN (hexagonal boron nitride nanosheets) powder, 6.66 g of NaOH (sodium hydroxide), 3.34 g of LiCl (lithium chloride), and 1 L of water were mixed and stirred until homogeneous. The resulting solution was then transferred to a stainless steel high-pressure reactor with a stirred polytetrafluoroethylene liner and subjected to hydrothermal treatment at 180°C for 2 hours. After the reaction solution was allowed to stand for 30 minutes, two-thirds of the solution was poured off. The resulting paste was transferred to a ball mill equipped with 1 mm and 10 mm zirconia balls and milled at 500 rpm for 5 hours. The mass ratio of 1 mm zirconia balls to 10 mm zirconia balls was 1:1, and the mass ratio of the paste to the zirconia balls was 1:2. After the reaction, the mixture was sonicated at 100 kHz for 30 min, followed by centrifugation at 2000 rpm for 15 min to remove any large, incompletely exfoliated components. The supernatant was slowly poured off, washed with distilled water, and then sonicated and centrifuged twice more. Finally, the collected supernatant was filtered through a polytetrafluoroethylene (PTFE) membrane, washed several times with copious amounts of distilled water, and freeze-dried for preservation to obtain the exfoliated boron nitride nanosheets (denoted as BNNS or HB-BNNS). 1 g of BNNS was uniformly dispersed in 200 mL of deionized water. Then, 0.5 g of dopamine was added to the mixture, and the pH was adjusted to 8 by adding tris(hydroxymethyl)aminomethane. The mixture was then stirred at 500 rpm for 1 hour at room temperature (25 °C). After the reaction, PDA-BNNS was filtered through a PVDF membrane (0.8 μm pore size), washed several times with deionized water, and dried in a 50 °C air-circulating oven for 12 h to obtain dopamine-modified boron nitride nanosheets (PDA-BNNS).

[0085] The bacterial cellulose solution was prepared as follows: First, a homogeneous BC suspension was freeze-dried for 48 h. The dried BC (2 wt%) was then added to a DMAC (N,N-dimethylacetamide) solution containing lithium chloride (8 wt%), and mechanically stirred (1000 rpm) for 12 h until completely dissolved. After standing for 12 h to remove air bubbles, a homogeneous bacterial cellulose solution was obtained for later use. The DMAC (N,N-dimethylacetamide) solution was prepared with a DMAC:deionized water volume ratio of 1:2.

[0086] The preparation process of PDA-BNNS / BC sol is as follows: An appropriate amount of the above bacterial cellulose solution was weighed and magnetically stirred at 60℃ for 3 hours to ensure complete dissolution. A certain amount of PDA-BNNS was added, and ultrasonically dispersed for 30 minutes to better disperse PDA-BNNS in the bacterial cellulose solution. The mass percentage of PDA-BNNS in the bacterial cellulose solution was 50%. Subsequently, the solution was magnetically stirred at 80℃ for 6 hours to ensure thorough dispersion, resulting in a uniform PDA-BNNS / BC sol with a certain viscosity. The sol was extruded using a syringe with an inner diameter of 0.72 mm at a speed of 3 mL / h. The axial orientation of PDA-BNNS was then adjusted by changing the pre-stretch winding speed by 0.6 r / min. The PDA-BNNS / BC gel was washed with deionized water to remove excess DMAC solvent and air-dried at 25℃ to obtain functional fibers. Example 1 is denoted as PDA-BNNS / BC or 3-0.6-dry or 3-0.6 or BC / 50PDA-BNNS or 50PDA-BNNS / BC.

[0087] Example 2: The pre-stretching winding speed was 0.1 r / min, and other test parameters were the same as in Example 1. Example 2 is denoted as 3-0.1.

[0088] Example 3: The pre-stretching winding speed was 0.3 r / min, and other test parameters were the same as in Example 1. Example 3 is denoted as 3-0.3.

[0089] Example 4: Pre-stretching winding speed 0.9 r / min, other test parameters are the same as in Example 1, Example 4 is denoted as: 3-0.9.

[0090] Comparative Example 1: Pure cotton fabric, denoted as Cotton.

[0091] Comparative Example 2: Fibers were obtained by wet spinning of bacterial cellulose solution using a syringe with an inner diameter of 0.72 mm. The extrusion speed was 3 mL / h, and the winding speed was 0.6 r / min. The BC gel was washed with deionized water to remove excess DMAC solvent and air-dried at 25°C. Comparative Example 2 is denoted as BC.

[0092] Comparative Example 3: Hexagonal boron nitride nanosheets, denoted as hBN.

[0093] Comparative Example 4: Hexagonal boron nitride nanosheets were sintered in air at 800°C for 1 hour. 30 g of the sintered hBN (hexagonal boron nitride nanosheets) powder, 6.66 g of NaOH (sodium hydroxide), 3.34 g of LiCl (lithium chloride), and 1 L of water were mixed and stirred until homogeneous. The resulting solution was then transferred to a stainless steel high-pressure reactor with a stirred polytetrafluoroethylene liner and subjected to hydrothermal treatment at 180°C for 2 hours. Comparative Example 4 is denoted as H-BNNS.

[0094] Comparative Example 5: The dopamine-modified boron nitride nanosheets (PDA-BNNS) from Example 1 were placed in a bacterial cellulose solution and magnetically stirred at 60°C for 3 hours to ensure complete dissolution. Ultrasonic dispersion for 30 minutes further dispersed the PDA-BNNS in the bacterial cellulose solution, achieving a PDA-BNNS mass percentage of 50%. Subsequently, the solution was magnetically stirred at 80°C for 6 hours to fully disperse the PDA-BNNS / BC sol with a uniform viscosity, which was then freeze-dried. Comparative Example 5 is designated 3-0-wet.

[0095] Comparative Example 6: The dopamine-modified boron nitride nanosheets (PDA-BNNS) from Example 1 were placed in a bacterial cellulose solution and magnetically stirred at 60°C for 3 hours to completely dissolve them. Ultrasonic dispersion for 30 minutes further dispersed the PDA-BNNS in the bacterial cellulose solution, resulting in a PDA-BNNS mass percentage of 50%. Subsequently, the solution was magnetically stirred at 80°C for 6 hours to fully disperse the PDA-BNNS / BC sol, yielding a uniform PDA-BNNS / BC sol with a certain viscosity. The sol was extruded using a syringe with an inner diameter of 0.72 mm at a speed of 3 mL / h. The winding speed was 0 r / min. The PDA-BNNS / BC gel was washed with deionized water to remove excess DMAC solvent and air-dried at 25°C to obtain fibers. Comparative Example 6 is designated 3-0.

[0096] Comparative Example 7: The dopamine-modified boron nitride nanosheets (PDA-BNNS) from Example 1 were placed in a bacterial cellulose solution and magnetically stirred at 60°C for 3 hours to ensure complete dissolution. Ultrasonic dispersion for 30 minutes further dispersed the PDA-BNNS in the bacterial cellulose solution, resulting in a PDA-BNNS mass percentage of 50%. Subsequently, the solution was magnetically stirred at 80°C for 6 hours to fully disperse the PDA-BNNS / BC sol, yielding a uniform PDA-BNNS / BC sol with a certain viscosity. The sol was extruded using a syringe with an inner diameter of 0.72 mm at a speed of 3 mL / h. The winding speed was 0.6 r / min. The PDA-BNNS / BC gel was washed with deionized water to remove excess DMAC solvent and then freeze-dried. Comparative Example 7 is denoted as 3-0.6-wet.

[0097] Comparative Example 8: The mass percentage of PDA-BNNS in the bacterial cellulose solution was 10%, and other parameters were the same as in Example 1.

[0098] Comparative Example 9: The mass percentage of PDA-BNNS in the bacterial cellulose solution was 30%, and other parameters were the same as in Example 1.

[0099] The functional fibers obtained in this case were also tested:

[0100] One of the key prerequisites for flexible BNNS-based composite films is the preparation of large, ultrathin BNNS sheets with good dispersibility. Large lateral dimensions of few-layer BNNS are particularly effective in enhancing the thermal conductivity of composite materials, which not only facilitates uniform and effective dopamine loading in the later stages but also allows for better control of the final composite fiber material thickness. Due to the strong lip-lip interactions between hBN sheets, it is difficult to exfoliate them into ultrathin nanosheets. A combined hydrothermal and ball milling method is used to exfoliate these sheets, forming few-layered and uniformly large BNNS sheets. During the hydrothermal process, under a synergistic effect, NaOH and LiCl insert into the interlayer spaces of adjacent hBN lattices, causing the hBN layer structure to expand. Rapid stirring promotes relative movement between adjacent hBN layers, and more ions enter the interlayer spaces, causing the nanosheets to become increasingly thinner under lateral forces. Subsequently, due to the increased spacing between hBN layers, in-situ ball milling with zirconia spheres makes it easier to exfoliate hBN into few-layered BNNS. This method significantly reduces the thickness of the BNNS, with a relatively small thickness dispersion, mostly between 1.6 nm and 2.5 nm.

[0101] To investigate the morphological changes during the exfoliation of boron nitride nanosheets, scanning electron microscopy (SEM) was used to analyze the morphology of the products at each stage. It was found that the thickness of the BNNS exfoliated by hydrothermal and ball milling gradually decreased, and the lateral dimension also decreased. The lateral dimension of the irregularly edged BNNS was approximately 1 μm-2 μm, with no obvious aggregation or stacking. The lateral dimension of the almost transparent BNNS was approximately 1.5 μm, and the lattice spacing of the boron nitride nanosheets became 0.34 nm, demonstrating that the thickness of the boron nitride nanosheets obtained by this invention is reduced.

[0102] Figure 1 The FTIR spectra of hBN, H-BNNS and HB-BNNS are as follows: Figure 1 As shown, in Figure 1 (a) The characteristic peaks are at 1365 cm⁻¹. -1 and 808cm -1 BN stretching and BN bending at the left and right sides. Compared with bulk hBN, H-BNNS and HB-BNNS at 3400cm -1The additional characteristic peaks are attributed to hydroxyl groups, indicating that the hexagonal boron nitride nanosheets not only achieved a reduction in the thickness of hexagonal boron nitride during hydrothermal and ball milling processes, but also achieved effective functionalization, which is beneficial for dispersion in water and lays the foundation for achieving uniform dopamine loading in dopamine solution in the later stage. Figure 1 (c) shows the XRD patterns of hBN, H-BNNS, and HB-BNNS samples. The peak values ​​of H-BNNS and HB-BNNS on the (002) plane show a significant decrease, with the peak value of HB-BNNS on the (002) plane decreasing from 26.74° to 26.69°. The interplanar distance (d-value) of hexagonal boron nitride after hydrothermal and ball milling increases from 0.3331 nm to 0.3434 nm, demonstrating that the greater decrease in the d-value of the (002) plane after hydrothermal and ball milling exfoliation is due to the acquisition of few-layer boron nitride nanosheets. Raman spectroscopy studies, such as... Figure 1 As shown in (b), the method of the present invention further demonstrates the structural change of hexagonal boron nitride nanosheets. Untreated hexagonal boron nitride nanosheets (hBN) have a structure at 1366 cm⁻¹. −1 A characteristic E2g peak appeared, corresponding to the high-frequency vibration of the in-plane B−N bond. In the HB-BNNS curve, a significant shift in the Raman shift of the E2g peak of the HB-BNNS obtained after hydrothermal ball milling was observed, indicating that the thickness of the hexagonal boron nitride nanosheets decreased after treatment using the method of this invention. XPS analysis showed... Figure 1 As shown in (d), the chemical structure of the boron nitride nanosheets of the present invention is further characterized, showing a B1 peak of 190.5 eV, an N1 peak of 397.8 eV, an O1 peak of 531.8 eV, and a C1 peak of 283.9 eV. The O and C peaks are attributed to background, which is typically detected in the support material during testing. The binding energy of the B1s electrons indicates that more O atoms are bound to B atoms on the surface of the boron nitride nanosheets of the present invention than in the original hBN. This is because the hexagonal boron nitride formed after hydrothermal treatment and ball milling brings in O atoms through the formation of functional hydroxyl groups. The presence of BO on the surface of the boron nitride nanosheets also verifies the presence of OH- groups on the surface of the boron nitride nanosheets.

[0103] PDA was used to modify the surface of boron nitride nanosheets to improve their miscibility and hydrophilicity with bacterial cellulose. To demonstrate the successful grafting of PDA onto the boron nitride nanosheet surface, FTIR spectra of BNNS and PDA-BNNS were acquired, such as... Figure 2 As shown in (b). In Figure 2 (b) PDA-BNNS at 1367.49cm -1 and 813.93cm -1Two sharp peaks appear nearby, corresponding to the B-N bending of the in-plane ring vibration in the E1u mode and the B-N-B bending of the out-of-plane vibration in the A2u mode, respectively. In addition, the PDA-BNNS peaks at 3400 cm⁻¹... -1 An OH stretching vibration peak also appears at this location, and it is more pronounced than the peak value of boron nitride nanosheets at this location. This is because a large amount of PDA is attached to the surface of boron nitride nanosheets, indicating that the method of the present invention can successfully load dopamine onto the surface of boron nitride nanosheets.

[0104] The PDA content is evaluated by analyzing the TGA curve. In the prior art, raw hBN is thermally stable when heated to 800°C. In this invention, as... Figure 2 As shown in (c), the mass loss of BNNS at heating to 800℃ is approximately 1.83%, which may be due to the adhesion of a small amount of -OH groups on the surface of the boron nitride nanosheets during ball milling in NaOH aqueous solution. The mass loss of PDA-BNNS is approximately 3.81%, considering that the weight loss rate of PDA at 800℃ is approximately 51.3%. [1] In this invention, the PDA content deposited on the surface of BNNS is about 3.86%, which also verifies that the dopamine of this invention was successfully loaded onto the surface of boron nitride nanosheets.

[0105] From the perspective of Raman spectroscopy, such as Figure 2 As shown in (a), the E2g peak of the few-layer BNNS is at 1369.3 cm⁻¹. -1 The E2g peak of the modified PDA-BNNS shifted to 1356.8 cm⁻¹. -1 The XRD results show that, Figure 2 As shown in (d), the modified PDA-BNNS has a significant and sharp peak at 26.65°, which is the peak value of BNNS on the (002) crystal plane, indicating that the modified PDA-BNNS still has a complete crystal plane structure.

[0106] During wet spinning, the extrusion speed and pre-stretching winding speed need to be matched. The pre-stretching winding speed enables the orientation and arrangement of nanofibers and the volume control of macrofibers. When PDA-BNNS / BC sol enters the coagulation bath through wet spinning, due to the limited space in the coagulation bath, the extrusion speed needs to be further adjusted according to the designed pre-stretching winding speed to ensure that the PDA-BNNS / BC sol is fully stretched after extrusion.

[0107] To ensure constant stretching conditions, a fixed winding roller diameter and winding speed were used, ranging from 0.1 r / min to 0.9 r / min, to obtain nanocomposite fibers with different strains. This embodiment used a winding speed of 0.6 r / min. This process ensures continuous fabrication and achieves a stretching rate of 100%, which is almost impossible to achieve with traditional wet-spun composite fibers. The cross-sectional morphology of the nanofibers during the fabrication process was characterized using SEM, such as... Figure 3 As shown, when the PDA-BNNS / BC sol is squeezed into the coagulation bath through a fine needle, the nanofibers are in a disordered state, and low-magnification cross-sectional electron microscopy reveals large pores between the nanofiber nanosheets, resembling a "lotus root" shape. Figure 3 (a) and Figure 3 As shown in (d), when the gel is wound at a certain speed, it is clearly observed that the gaps between the nanofibers and the dopamine-modified boron nitride nanosheets become smaller. This is because during the stretching process, as the DMAC solution evaporates and is replaced by water, the stretching force causes the nanofibers to slip and arrange themselves in an orderly manner, thus achieving good alignment of the nanofibers and greatly reducing macroscopic fiber defects. However, the presence of BC nanofibers can still be clearly observed, such as... Figure 3 (b) and Figure 3 As shown in (e), a densely ordered PDA-BNNS / BC nanocomposite fiber was obtained after further air drying of the gel, as shown in [example image]. Figure 3 As shown in (c) and (f), it can be seen that in this invention, the pre-winding speed can achieve good alignment of nanofibers and reduce the diameter of macrofibers.

[0108] From the cross-sectional image of the macroscopic fiber, such as Figure 4 (e)- Figure 4 As shown in (g). It can be seen that with the increase of winding speed (where... Figure 4 (e) has a winding speed of 0.1 r / min. Figure 4 (f) has a winding speed of 0.6 r / min. Figure 4(g) With a winding speed of 0.9 r / min, more nanofibers were observed to align along the stretching direction. The dense, layered stacking structure is similar to the layered structure of nacre and plant cell walls, indicating that the composite fiber has high mechanical properties. This is due to the combined effect of DMAC volatilization and winding speed; the layered structure of the nanofibers gradually becomes denser with increasing winding speed, but winding speeds greater than 0.9 r / min can cause excessive stress on the fibers, leading to breakage. As DMAC volatilizes, the nanofibers tend to assemble into more compact microfiber bundles through hydrogen bonding, resulting in a more compact macrofiber structure. At an extrusion speed of 3 mL / h, when the PDA-BNNS / BC sol enters the coagulation bath through wet spinning, the limited space can induce PDA-BNNS self-assembly, thereby promoting the directional alignment of nanofibers. Figure 4 As shown in (f), under the constraint effect of effective volume, the cross-sectional image of the fibers reveals an axially ordered arrangement in the PDA-BNNS. It is evident that achieving the directional ordered arrangement of nanofibers requires balancing the extrusion speed and the pre-stretching winding speed.

[0109] Using small-angle X-ray scattering (SAXS) characterization techniques, the orientation degree is quantified by calculating the Hellmann orientation parameters, such as... Figure 5 As shown. In Figure 5 In (a), the orientation degree (f) was quantified by calculating the Hermann orientation parameters. The orientation degree (f) was obtained by azimuth scanning in SAXS mode using the Ruland stripe method. The orientation degree (f) was calculated for composite fibers before winding (i.e., 3-0-wet), after winding at a speed of 0.6 r / min (i.e., 3-0.6-wet), and after air-drying at a speed of 0.6 r / min (i.e., 3-0.6-dry). The calculation results showed that from the start of wet spinning to the end of air-drying, the orientation degree (f) of PDA-BNNS in the composite fiber increased from 0.66 to 0.78. The continuous increase in the draw ratio indicates that the preferred winding speed, acting as a strong external shear force, is more conducive to fiber alignment along the axial direction. The orientation degree (f) was calculated for composite fibers prepared at different winding speeds and after air-drying, as follows: Figure 5 As shown in (b), it can be observed that the orientation degree (f) of the composite fiber increases with increasing winding speed; the cross-sectional diameter of the fiber also decreases from 472.8 μm to 122.9 μm with increasing winding speed, and a denser lamellar structure is observed, such as... Figure 4 (a)- Figure 4 (c) Verification (wherein) Figure 4 (a) The winding speed is 0.1 r / min. Figure 4 (b) The winding speed is 0.6 r / min. Figure 4(c) The winding speed is 0.9 r / min. In summary, PDA-BNNS / BC fibers exhibit superior orientation and a highly packed lamellar structure when combined with winding and extrusion speeds.

[0110] Furthermore, to investigate the mechanism of action of PDA-BNNS in PDA-BNNS / BC composite fibers, the changes in the morphology and structure of composite fibers with different PDA-BNNS contents were also studied. For example... Figure 6 Electron micrographs of composite fibers with different PDA-BNNS contents from Example 1 and Comparative Examples 8-9 are shown. The cross-section of pure BC nanocomposite fibers exhibits an irregular shape, as shown... Figure 6 (a) and Figure 6 As shown in (d) (Comparative Example 8), with the increase of PDA-BNNS content, the cross-section of the PDA-BNNS / BC composite fiber gradually approaches a circle, as shown in Comparative Example 9. Figure 6 (b) and Figure 6 (e) and Example 1 ( Figure 6 (c)- Figure 6 As shown in (f), this is because PDA-BNNS are tightly packed between nanofibers, and the wet spinning volume effect restricts the cross-sectional shape of the composite fiber. The formation of hydrogen bonds between nanofibers and PDA-BNNS helps to make the surface of PDA-BNNS / BC composite fiber smoother.

[0111] Thermal control capability is crucial for the function and lifespan of electronic components, especially in portable electronics and wearable devices. Therefore, the thermal pathway of PDA-BNNS / BC nanocomposite fiber woven fabric was characterized using the transient planar heat flow method. Figure 7 As shown in (b), the thermal conductivity (Ka) in the fabric plane was tested by preparing PDA-BNNS / BC nanocomposite fiber woven fabrics at different winding speeds. ∥ ).exist Figure 7 In (b), it can be observed that changing the winding speed can improve the in-plane thermal conductivity of the fabric. When PDA-BNNS is randomly or ordered distributed in the bacterial cellulose polymer material, the thermal conductivity of the PDA-BNNS / BC fabric gradually increases. Considering both thermal conductivity and composite fiber volume factor, the optimal winding speed during wet spinning is 0.6 r / min, and the optimal extrusion speed is 3 mL / h.

[0112] Due to the well-designed oriented PDA-BNNS / BC micronetwork, this composite nanofiber and woven textile exhibit impressive thermal conductivity. In this study, a transient electrothermal technique (TET) was used to measure the axial thermal conductivity of the nanocomposite fibers. Figure 7As shown in (a), the axial thermal conductivity of the PDA-BNNS / BC composite fiber is shown. Studies have found that with the same amount of PDA-BNNS added, a certain winding speed helps improve the axial thermal conductivity of the composite fiber. This is mainly due to the highly anisotropic thermal conductivity of PDA-BNNS. Due to the synergistic effect between volume confinement and winding speed, PDA-BNNS can self-assemble into more ordered, axially aligned heat transfer paths, thereby promoting effective axial phonon transport, thus improving the thermal conductivity of the fabric. A certain winding speed promotes the axial alignment of PDA-BNNS, increases the connection between PDA-BNNS sheets, and reduces interfacial phonon scattering within the composite fiber. Therefore, in Figure 7 (a) The thermal conductivity of the composite fibers can reach 7.92 W / (m·K). Furthermore, according to the transient plane heat flow meter method, PDA-BNNS / BC textiles can have a high thermal conductivity of 0.294 W / (m·K), such as... Figure 7 As shown in (b).

[0113] The personal cooling performance of the textile of Example 1 compared to pure cotton textile was studied using infrared camera testing. The cooling efficiency of the attached textile was demonstrated by measuring its outer surface temperature, which reflects the heat exchange efficiency between the textile and the surrounding environment. Both the textile of Example 1 and the pure cotton textile were attached to the skin for a period of time until the outer surface temperature stabilized. Then, the temperature distribution was recorded using an infrared thermal imaging camera. Figure 7 (c)- Figure 7 As shown in (d), the results indicate that the outer surface temperature of the BC / 50PDA-BNN textile can reach 30°C, which is 0.7°C higher than that of pure cotton textiles and closer to the temperature of human skin. This means that, due to the effective phonon transmission within the composite fibers of this invention, the heat generated by the human body can be effectively transferred to the outer surface of the textile. The higher surface temperature of the textile facilitates the transfer of heat generated by the body from the skin to the external environment through thermal radiation and heat exchange, playing an important role in the wearer's thermal comfort.

[0114] To further examine the cooling efficiency of the composite fiber of the present invention for electronic devices, heat dissipation experiments were conducted on fabric samples woven from 50PDA-BNN / BC composite fibers and pure cotton fabrics, respectively. Figure 8 (a) An LED module (rated power approximately 10W) ​​was used. An infrared thermal imaging camera was used to record the hotspot temperature of the LED chip. The resulting temperature distribution and the infrared thermal image of the fabric are shown below. Figure 8 (d) and Figure 8As shown in (f), the results clearly show that the surface temperature of the fabric sample woven using the prepared 50PDA-BNN / BC composite fiber rose to 43.8℃ within 120 s, which is 3.9℃ lower than the 47.7℃ of the pure cotton fabric. To further simulate the heat dissipation performance of the 50PDA-BNN / BC composite fiber woven fabric sample on the human body, both the cotton fabric and the 50PDA-BNN / BC composite fiber woven fabric sample were simultaneously placed on a 40℃ hot plate, as shown in (f). Figure 8 (b) Record the temperature change of the sample over time, and the results are as follows: Figure 8 (c) and Figure 8 As shown in (e), at 60 s, the surface temperature of the fabric sample woven from 50PDA-BNNS / BC composite fibers reached 39°C, which is 3.4°C higher than the surface temperature of pure cotton fabric (35.6°C). This demonstrates that the fabric woven from 50PDA-BNNS / BC composite fibers can quickly transfer the temperature from the surface of the heating element. This high thermal conductivity is due to the synergistic effect of several factors: First, the method of this invention yields fibers with good flexibility, small pinholes, and high tensile force. Furthermore, the PDA-BNNS fibers are aligned and aligned along the in-plane direction, so the in-plane thermal conductivity is mainly determined by the thermal conductivity of the (002) plane. Second, the overlapping of sheet-like PDA-BNNS fibers significantly reduces the thermal resistance between nanosheets, and the abundant, continuous PDA-BNNS nanosheets form a dense thermally conductive network through the polymer.

[0115] This study utilizes a wet spinning process to prepare a biodegradable, thermally conductive PDA-BNNS / BC textile, which is low-cost, environmentally friendly, and suitable for large-scale production. The PDA-BNNS / BC nanocomposite fibers exhibit a high tensile strength of 86 MPa and a good axial thermal conductivity of 7.92 W / (m·K), superior to most polymer / boron nitride composite fibers. Due to the uniform dispersion and orderly arrangement of PDA-BNNS, infrared camera tests show that when the woven PDA-BNNS / BC textile is attached to the skin, it provides better static personal cooling than commercial cotton textiles, displaying a surface temperature closer to that of the skin, thus facilitating heat dissipation. Furthermore, the PDA-BNNS / BC textile still exhibits good thermal conductivity under LED lights and on a heated platform. The synergistic effect between these excellent thermal conductivity properties also endows it with remarkable personal cooling effects, offering new possibilities for wearable electronic device systems.

[0116] In summary, this invention successfully embeds boron nitride into fibers, resulting in a composite fiber with improved thermal conductivity and reduced volume, thus achieving a composite fiber with smaller volume and better thermal conductivity.

[0117] It should be noted that the terminology used in this invention is for describing specific embodiments only and is not intended to limit the scope of this application. As shown in this specification, unless the context clearly indicates otherwise, words such as "a," "an," "an," and / or "the" do not specifically refer to the singular and may include the plural. The terms "comprising," "including," or any other variations thereof are intended to cover a non-exclusive inclusion, such that a process, method, 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 a process, method, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, or apparatus that includes said element.

[0118] It should also be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. Unless otherwise expressly specified and limited, the terms "installed," "connected," "linked," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components. For those skilled in the art, the specific meaning of the above terms in the present invention can be understood according to the specific circumstances.

[0119] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the technical solutions of the embodiments of the present invention.

[0120] References:

[0121] [1]SHEN H, GUO J, WANG H, et al. Bioinspired modification of h-BN forhigh thermal conductive composite films with aligned structure[J]. ACSApplied Materials&Interfaces, 2015, 7(10): 5701-5708.

Claims

1. A functional fiber with embedded boron nitride nanosheets, characterized in that, The method for preparing the functional fiber includes the following steps: S1. Obtaining dopamine-modified boron nitride nanosheets: Hexagonal boron nitride was sintered in air at 800℃ for 1 hour. 30g of the sintered hexagonal boron nitride was placed in a mixed solution, and the mixed solution was subjected to a hydrothermal reaction at 180℃ for 2 hours to obtain a paste. The paste was ball-milled using zirconia balls with diameters of 1mm and 10mm, wherein the mass ratio of the 1mm and 10mm zirconia balls was 1:1, and the mass ratio of the paste to the zirconia balls was 1:

2. The paste was then sonicated at 100kHz for 30 minutes, centrifuged, and washed to obtain boron nitride nanosheets. The boron nitride nanosheets were dispersed in a dopamine solution and modified at room temperature. The pH of the dopamine solution was adjusted to 8, the concentration of the dopamine solution was 0.5g / 200mL, and the concentration of the boron nitride nanosheets in the dopamine solution was 1g / 200mL. The modification was carried out at room temperature to obtain dopamine-modified boron nitride nanosheets. S2: Dopamine-modified boron nitride nanosheets are dissolved in a bacterial cellulose solution, with the mass ratio of dopamine-modified boron nitride nanosheets in the bacterial cellulose solution being 50%. After uniform mixing, functional fibers are obtained by wet spinning, wherein the extrusion speed of the wet spinning method is 3 mL / h, the pre-stretching winding speed is 0.6 r / min, and the fibers are air-dried to obtain the functional fibers. Air dry at 25℃; The preparation process of the bacterial cellulose solution includes: adding the dried bacterial cellulose to an N,N-dimethylacetamide solution containing lithium chloride, mixing evenly, and removing air bubbles.

2. The functional fiber according to claim 1, characterized in that, The preparation process of the mixed solution in S1 is to dissolve sodium hydroxide and lithium chloride in water; The concentration of sodium hydroxide in the mixed solution is 6.66 g / L; The concentration of lithium chloride in the mixed solution is 3.34 g / L.

3. The functional fiber according to claim 1, characterized in that, The concentration of the 30g hexagonal boron nitride nanosheets sintered in S1 in the mixed solution is 30g / L.

4. The functional fiber according to claim 1, characterized in that, The ball mill operates at a speed of 500 rpm and the milling time is 4.5-5.5 hours. The centrifugation speed is 1500rpm-2500rpm, and the centrifugation time is 3h-8h.

5. The functional fiber according to claim 1, characterized in that, The solution in S1 used to adjust the pH of the dopamine solution to 8 is tris(hydroxymethyl)aminomethane.

6. The functional fiber according to claim 1, characterized in that, The modification step in S1 at room temperature is as follows: at 25°C, the dopamine solution containing boron nitride nanosheets is stirred at a speed of 400-600 rpm for 50-70 minutes.

7. The functional fiber according to claim 1, characterized in that, The bacterial cellulose was present at a mass ratio of 2% in an N,N-dimethylacetamide solution containing lithium chloride. The mass ratio of lithium chloride in the N,N-dimethylacetamide solution containing lithium chloride is 8%.

8. The functional fiber according to claim 1, characterized in that, The step of uniform mixing in S2 includes ultrasonication and stirring; The ultrasound duration is 25-35 minutes. The stirring time is 5-7 hours, and the stirring temperature is 70℃-90℃.

9. The use of the functional fiber according to any one of claims 1-8 in fabrics.

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