A strain interference resistant temperature sensing fiber and method of making same

Abstract

The application relates to the technical field of fibers, and discloses a strain-interference-resistant temperature sensing fiber and a preparation method thereof. The temperature sensor comprises a core layer and an outer layer wrapped outside the core layer; the core layer is a conductive layer, and the core layer has a spiral structure; and the outer layer is made of a polymer material. The strain-interference-resistant temperature sensing fiber provided by the application has a double-layer composite spiral structure obtained through cooperation of the core layer and the outer layer, and a disulfide bond dynamic network is introduced into the core layer. Through the design of the double-layer composite spiral structure and the disulfide bond dynamic network of the core layer, effective decoupling of strain and temperature signals is realized. Compared with a traditional temperature sensor, the temperature sensor provided by the application can significantly reduce the interference of strain on strain measurement under different strain levels, improve the accuracy of temperature measurement, and endow the temperature sensor with high strain-interference-resistant capability.

Description

Technical Field

[0001] This invention relates to the field of fiber technology, and in particular to a temperature sensing fiber resistant to strain interference and its preparation method. Background Technology

[0002] Flexible temperature sensors are in high demand in fields such as healthcare and industrial monitoring, but traditional sensors (such as metal thermistors and semiconductor devices) are susceptible to mechanical strain interference, leading to temperature signal distortion. Especially in wearable applications, strain generated by human movement can significantly affect measurement accuracy (error > 10%).

[0003] Currently, common temperature sensor types include thermocouples, thermistors, and semiconductor temperature sensors. Taking thermistors as an example, they measure temperature by utilizing the characteristic that the resistance of a material changes with temperature. However, thermistors suffer from relatively low sensitivity and slow response speed. Moreover, their resistance changes when subjected to mechanical strain, leading to deviations in temperature measurement results. Similarly, traditional wearable temperature sensors are difficult to guarantee in terms of measurement accuracy when subjected to strain such as stretching and bending during human movement. This means that traditional temperature sensors are susceptible to strain interference in complex environments, resulting in decreased measurement accuracy. Summary of the Invention

[0004] To address the aforementioned technical problems, the present invention provides a temperature sensing fiber resistant to strain interference, comprising a core layer and an outer layer covering the outside of the core layer; the core layer is a conductive layer and has a helical structure; the outer layer is made of a polymer material.

[0005] The core layer is prepared by a wet spinning process using a core layer spinning solution; the core layer spinning solution includes conductive filler, thermoplastic polyurethane, functional monomers containing disulfide bonds, and dibutyltin dynamic crosslinking catalyst.

[0006] Furthermore, the functional monomer containing disulfide bonds is diacrylic acid disulfide.

[0007] Furthermore, the dibutyltin dynamic crosslinking catalyst is dibutyltin dilaurate.

[0008] Furthermore, the conductive filler is a carbon nanotube.

[0009] Further, the mass fraction of conductive filler in the core spinning solution ranges from 0.40% to 1.40%; the mass ratio of the total amount of thermoplastic polyurethane, the functional monomer containing disulfide bonds, and the dibutyltin dynamic crosslinking catalyst to the conductive filler is 1:(0.05-0.17); the mass ratio of the functional monomer containing disulfide bonds to the thermoplastic polyurethane is (5-8):100; and the mass ratio of the dibutyltin dynamic crosslinking catalyst to the thermoplastic polyurethane is (0.1-0.3):100.

[0010] Furthermore, the helical pitch of the spiral structure ranges from 1 to 3 mm.

[0011] Furthermore, the outer layer is prepared using an outer layer spinning solution via a wet spinning process.

[0012] Furthermore, the outer spinning solution includes thermoplastic polyurethane.

[0013] Furthermore, the outer spinning solution also includes phenylboronic acid.

[0014] Another objective of this application is to provide a method for preparing the strain-resistant temperature sensing fiber as described above, comprising the following steps:

[0015] S1: Preparation of outer spinning solution;

[0016] S2: Preparation of core layer spinning solution;

[0017] S3: A wet spinning device with three coaxial needles is used. The inner needle extrudes the core spinning solution, the middle needle delivers deionized water, and the outer needle extrudes the outer spinning solution. The extrusion flow rate of the core spinning solution is 1-2 mL / h, the extrusion flow rate of the deionized water is 4 mL / h, and the extrusion flow rate of the outer spinning solution is 2 mL / h. The external drawing speed is 250-500 mm / min. After spinning, the temperature sensing fiber with the highest resistance to strain interference is obtained after preliminary shaping and drying.

[0018] The embodiments of the present invention have the following technical effects:

[0019] The strain-resistant temperature sensing fiber provided in this application has a double-layer composite helical structure formed by the combination of the core layer and the outer layer, and a disulfide bond dynamic network is introduced into the core layer. Through the design of this double-layer composite helical structure, combined with the disulfide bond dynamic network of the core layer, the strain and temperature signals are effectively decoupled. Under different strain levels, compared with traditional temperature sensors, the temperature sensor provided in this application can significantly reduce the interference of strain on strain measurement, improve the accuracy of temperature measurement, and endow the temperature sensor with high resistance to strain interference. Attached Figure Description

[0020] 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.

[0021] Figure 1 This is a schematic diagram of the wet spinning process used to prepare temperature-sensing fibers in this invention.

[0022] Figure 2 This is a schematic diagram of the sample preparation process for pitchless, large-pitch, and small-pitch samples in this invention;

[0023] Figure 3 These are electron microscope images of the surface and cross-section of the temperature sensing fiber prepared in Example 1 of this invention;

[0024] Figure 4 The relative resistance changes of sensing fibers with 1.08% and 1.40% CNT mass fraction in this invention correspond to strain ranges of 20%, 50%, and 100%.

[0025] Figure 5 This is a temperature-resistivity change rate graph of fibers with CNT concentrations of 0.40%-1.08%wt in this invention;

[0026] Figure 6 This is a temperature-resistivity change rate graph of fibers with a CNT concentration of 1.23%wt in this invention;

[0027] Figure 7 This is a temperature-resistance change rate graph of the temperature sensing fiber prepared in Example 1 of the present invention under stretching of 0%, 15%, and 30%. Detailed Implementation

[0028] 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 part of this invention.

[0029] Textile-based flexible temperature sensors can be mainly classified into thermal resistance-based and thermoelectric-based flexible temperature sensors according to their sensing mechanisms. The resistance of flexible sensors based on the thermal resistance effect tends to decrease or increase with increasing temperature, exhibiting negative temperature coefficient of resistance (NTC) and positive temperature coefficient of resistance (PTC) effects. Thermal resistance-based flexible temperature sensors have high sensitivity and simple fabrication processes, but are easily affected by strain during use.

[0030] Based on this, this application aims to solve the problem that traditional temperature sensors suffer from reduced measurement accuracy due to strain interference in complex environments, and provides a temperature sensing fiber with anti-strain interference capability, enabling it to accurately and stably measure temperature under complex working conditions such as human movement and industrial equipment vibration.

[0031] To address the problem of decreased measurement accuracy caused by strain interference in complex environments, this application provides a strain-resistant temperature sensing fiber. The temperature sensing fiber includes a core layer and an outer layer covering the outside of the core layer. The core layer is a conductive layer with a helical structure. The outer layer is a protective layer. To impart textile processability to the temperature sensing fiber, this application preferably uses a polymer material for the outer layer.

[0032] The detection principle of temperature sensing fibers mainly relies on the change in resistivity of the conductive layer with temperature. Therefore, the ambient temperature is usually deduced from the measured resistance value by measuring the change in resistance of the temperature sensing fiber and using the resistance-temperature relationship curve. However, in practical applications, especially in wearable scenarios, temperature sensing fibers are inevitably affected by mechanical strains such as tension and bending. These strains, such as tensile strain, can directly cause the conductive path to be elongated, thinned, or partially broken, increasing resistance. Bending strain can cause local stress concentration, changing local conductivity. The resistance change caused by this strain is superimposed and coupled with the resistance change caused by temperature change, resulting in temperature readings that are too high or too low. It is also difficult to distinguish whether the resistance change is caused by temperature change or strain, which seriously interferes with the temperature measurement results, produces errors, and may even cause the readings to fail.

[0033] This application sets the conductive layer as the core layer and sets the core layer as a spiral structure. Through a unique axial unfolding mechanism, it achieves physical decoupling of strain and temperature signals, effectively suppressing the interference of mechanical deformation on the stability of the conductive network.

[0034] Specifically, this application sets the conductive layer as the core layer and sets the core layer as a spiral structure based on the detection principle of the temperature sensor. This spiral configuration spatially decouples the temperature sensing functional layer (CNT conductive network) from external strain through a physical separation mechanism, ensuring that temperature changes dominate the resistance response, while strain interference is absorbed by the deformation mechanism of the spiral, thereby achieving stable sensing of temperature signals in dynamic environments. In addition, when the fiber is subjected to tensile strain, the spiral structure disperses external stress by axially unfolding (i.e., increasing the spiral spacing) rather than directly stretching the conductive material itself. This deformation mode effectively avoids the breakage or irreversible deformation of the carbon nanotube conductive path, thereby maintaining the stability of the conductive network. Specifically, the spiral curling shape gradually unfolds under elastic constraints, transforming linear stretching into rotational deformation, which significantly reduces the effective strain applied to the conductive core layer. At the same time, the extended path design of the spiral structure (such as the small-pitch spiral having a longer conductive path for the same length) enhances the strain buffering capacity. Especially at higher strain levels (50%~100%), the small-pitch spiral, due to its compact structure, can suppress local stress concentration inside the fiber and significantly reduce resistance fluctuations (ΔR / R0), where R0 is the initial resistance and ΔR is the resistance change value.

[0035] Furthermore, this application preferably uses a core layer spinning solution prepared by a wet spinning process; and further preferably, the core layer spinning solution includes conductive filler, thermoplastic polyurethane, functional monomers containing disulfide bonds, and dibutyltin dynamic crosslinking catalyst, so as to introduce a dynamic network of disulfide bonds in the core layer. The disulfide bonds dissipate mechanical energy through reversible breakage / recombination, thereby improving stability and ensuring measurement accuracy through the physical decoupling synergistic effect of the dynamic bond network and the helical structure.

[0036] The strain-resistant temperature sensing fiber provided in this application has a double-layer composite helical structure formed by the combination of the core layer and the outer layer, and a disulfide bond dynamic network is introduced into the core layer. Through the design of this double-layer composite helical structure, combined with the disulfide bond dynamic network of the core layer, the strain and temperature signals are effectively decoupled. Under different strain levels (20%-100%), compared with traditional temperature sensors, the temperature sensor provided in this application can significantly reduce the interference of strain on strain measurement, improve the accuracy of temperature measurement, and endow the temperature sensor with high resistance to strain interference.

[0037] To introduce disulfide bonds, this application preferably uses diacrylic acid disulfide as the functional monomer containing disulfide bonds; and preferably uses dibutyltin dilaurate as the dynamic crosslinking catalyst.

[0038] To impart conductivity to the core layer, this application preferably includes a conductive filler in the core layer, and more preferably, the conductive filler is carbon nanotubes (CNTs).

[0039] Specifically, this application preferably uses a conductive filler mass fraction in the core spinning solution ranging from 0.40% to 1.40%, and further preferably from 0.83% to 1.08%, to ensure conductivity while achieving the optimal balance between the flexibility and strength of the temperature-sensing fiber. The preferred mass ratio of the total amount of thermoplastic polyurethane, the disulfide-containing functional monomer, and the dibutyltin dynamic crosslinking catalyst to the conductive filler is 1:(0.05-0.17); wherein the mass ratio of the disulfide-containing functional monomer to the thermoplastic polyurethane is (5-8):100; and the mass ratio of the dibutyltin dynamic crosslinking catalyst to the thermoplastic polyurethane is (0.1-0.3):100.

[0040] To ensure the temperature sensor's resistance to strain interference, this application preferably uses a spiral structure with a pitch range of 1-3 mm, so as to select appropriate pitch parameters according to different application scenarios and achieve effective resistance to different strain levels.

[0041] The outer layer of this application is preferably prepared by a wet spinning process using an outer spinning solution; and preferably, the outer spinning solution includes thermoplastic polyurethane (TPU). The outer TPU material gives the temperature sensing fiber good flexibility and processability, which makes it easy to integrate into textiles and broadens the application scope of temperature sensors in wearable devices and other fields.

[0042] Furthermore, this application preferably includes phenylboronic acid in the outer spinning solution, so as to modify TPU with phenylboronic acid, a borate ester dynamic bond modifier, by adding phenylboronic acid to the outer spinning solution, thereby preparing a composite material with a dynamic covalent bond network.

[0043] In this application, the mass of phenylboronic acid in the outer spinning solution is preferably 3%-5% of the mass of TPU.

[0044] As described above, the strain-resistant temperature sensing fiber provided in this application has a double-layer composite helical configuration, including an inner carbon nanotube conductive layer and an outer thermoplastic polyurethane protective layer. By adjusting the mass fraction of carbon nanotubes and the pitch parameters of the helical structure, the strain and temperature signals are decoupled, improving the accuracy of temperature measurement. The optimized CNT mass fraction and helical structure enable the temperature sensing fiber to have high sensitivity to temperature changes, allowing it to respond quickly to temperature changes and achieve accurate temperature monitoring, thus giving the temperature sensing fiber excellent temperature response performance.

[0045] Furthermore, the temperature sensing fiber adopts a double-layer composite spiral configuration. By controlling parameters such as the flow rate and stretching speed of the carbon nanotube solution in the core layer through a wet spinning process, the inner CNT conductive layer forms a spiral structure (pitch 1-3 mm), and the outer TPU protective layer forms a dynamic self-healing barrier. The spiral structure achieves physical decoupling of strain and temperature signals, and the dynamic disulfide bonds dissipate mechanical energy through reversible breakage / recombination, further suppressing resistance fluctuations caused by strain.

[0046] The temperature sensing fiber provided in this application possesses dynamic bond-enhanced stability and self-healing capabilities. By introducing a disulfide bond dynamic network into the inner CNT conductive layer and adding a borate ester bond modifier to the outer TPU protective layer, a synergistic enhancement of strain-temperature dual decoupling is achieved. The disulfide bonds dissipate mechanical energy through reversible fracture / recombination, while the borate ester bonds endow the protective layer with self-healing functionality, significantly improving the fiber's lifespan under complex operating conditions (such as vibration and repeated bending). The physical decoupling and synergistic effect of the dynamic bond network and the helical structure achieves high stability without additional encapsulation processes. This temperature sensing fiber exhibits high elongation at break and high tensile strength. The large-pitch helical structure fiber demonstrates high deformability at low mass fractions, meeting the requirements for sensor flexibility and durability in wearable devices and industrial monitoring, thus endowing the temperature sensing fiber with excellent mechanical properties.

[0047] Another objective of this application is to provide a method for preparing the strain-resistant temperature sensing fiber as described above. Preferably, the temperature sensing fiber is prepared by wet spinning, as illustrated in the schematic diagram of the wet spinning process. Figure 1 As shown; specifically, the preparation method includes the following steps:

[0048] S1: Preparation of outer spinning solution;

[0049] S2: Preparation of core layer spinning solution;

[0050] S3: A wet spinning device with three coaxial needles is used. The inner needle extrudes the core spinning solution, the middle needle delivers deionized water, and the outer needle extrudes the outer spinning solution. The extrusion flow rate of the core spinning solution is 1-2 mL / h, the extrusion flow rate of the deionized water is 4 mL / h, and the extrusion flow rate of the outer spinning solution is 2 mL / h. The external drawing speed is 250-500 mm / min, the coagulation bath temperature is 40-45℃, and the ambient humidity is 20±5% RH. The induced helical structure and dynamic bond network are formed synchronously. After spinning, the fiber is pre-shaped and dried to obtain the most strain-resistant temperature-sensing fiber. After spinning, the nascent fiber is immersed in a 0.5% H2O2 solution for oxidative curing for 1 hour, then annealed at 80℃ for 30 minutes, and then soaked in deionized water for 48 hours to shape the outer TPU layer. After drying for 24 hours, the finished fiber, i.e., the strain-resistant temperature-sensing fiber, is obtained.

[0051] The method for preparing strain-resistant temperature sensing fibers provided in this application involves precisely controlling the extrusion flow rate of each layer of solution and using the flow rate difference between the solutions to induce the CNT solution to form a spiral structure. The flow rate of the deionized water in the middle layer is lower than that of the inner layer, which can cause the inner layer to solidify instantly after it comes out, thus folding into a spiral shape. By adjusting the external stretching speed, the pitch parameters of the spiral structure are controlled, and temperature sensing fibers with different spiral pitches are prepared.

[0052] The sample preparation processes for no pitch, large pitch, and small pitch are as follows: Figure 2 As shown.

[0053] The preferred preparation method of the outer layer spinning solution in this application includes: adding thermoplastic polyurethane elastomer to a solvent, stirring until dissolved, adding phenylboronic acid, and magnetically stirring until completely dissolved to form a uniform and transparent modified outer layer spinning solution; wherein the ratio of thermoplastic polyurethane elastomer to the solvent is (3-4) g: 15 mL; and the mass of phenylboronic acid is 3%-5% of the mass of TPU. Preferably, the solvent used in the preparation of the outer layer spinning solution in this application is N,N-dimethylformamide (DMF).

[0054] The preferred preparation method of the core spinning solution in this application includes: adding thermoplastic polyurethane elastomer to a solvent, stirring, adding conductive filler, and simultaneously adding diacrylic acid disulfide (DSDA) and dibutyltin dilaurate catalyst; continuing to stir for 5 hours, and ultrasonically treating for 30 minutes to obtain a black inner layer spinning solution containing a dynamic disulfide bond network, i.e., the core spinning solution; the preferred solvent in this step is a mixed solvent composed of DMF and anhydrous ethanol in a volume ratio of 10:1.

[0055] In preparing the core spinning solution, magnetic stirring combined with ultrasonic treatment is used to improve the dispersibility of carbon nanotubes in the solution and ensure the uniformity and spinnability of the spinning solution.

[0056] This application employs a three-needle wet spinning process. By controlling parameters such as the flow rate of the core carbon nanotube solution and the stretching speed during the spinning process, the inner carbon nanotube solution is induced to form a helical structure, while the outer thermoplastic polyurethane solution forms a protective layer, thereby preparing a sensing fiber with a double-layer composite helical configuration.

[0057] To suppress the dynamic aggregation of carbon nanotubes (CNTs) during the spinning and extrusion process, this application introduces a real-time ultrasonic-assisted device in the wet spinning stage. Specifically, the three-layer needle assembly is immersed in the conductive medium (25°C deionized water) of an ultrasonic cleaner, and 40kHz ultrasonic irradiation (power density 0.5W / cm³) is applied simultaneously with fiber extrusion and solidification. This in-situ treatment continuously agitates the spinning solution flow through microjets generated by cavitation, effectively preventing the re-aggregation of CNTs during phase separation, thereby ensuring the uniformity of the conductive network in the core layer during the spiral structure formation process. The ultrasonic parameters are dynamically optimized based on the viscosity of the spinning solution: when the CNT mass fraction is ≥1.08%wt, the power density is increased to 0.8W / cm³ to avoid local aggregation in high-concentration systems due to insufficient ultrasonic energy.

[0058] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0059] Example 1

[0060] This embodiment provides a method for preparing a temperature sensing fiber resistant to strain interference, comprising the following steps:

[0061] S1: Preparation of outer TPU solution: Accurately measure 15ml of LDMF as solvent, add 3.50g of TPU particles, stir on a magnetic stirrer until completely dissolved, then add 0.18g of phenylboronic acid, stir magnetically until completely dissolved, to form a uniform and transparent outer spinning solution.

[0062] S2: Preparation of core layer CNT / TPU composite spinning solution: 10 mL of LDM and 1 mL of anhydrous ethanol were measured sequentially as a mixed solvent, 0.94 g of TPU particles were added, and after pre-stirring for 3 hours, 0.05 g of multi-walled carbon nanotubes (MWCNTs) were added, with a CNT mass fraction of 0.40%. Simultaneously, 0.06 g of diacrylate disulfide (DSDA, accounting for 6% of the TPU mass) and 0.002 g of dibutyltin dilaurate catalyst were added. After stirring for another 5 hours, ultrasonic treatment was performed for 30 minutes to obtain a black inner layer spinning solution containing a dynamic disulfide bond network, i.e., core layer spinning solution.

[0063] S3: Fiber Preparation: A wet spinning device with three coaxial needles was used, employing 22G / 17G / 13G coaxial needles (inner diameters of 0.4mm / 1.05mm / 1.9mm). The entire three-layer needle assembly was immersed in the conductive medium (25℃ deionized water) of an ultrasonic cleaner. Simultaneously with fiber extrusion and coagulation, 40kHz ultrasonic irradiation (power density 0.5W / cm³) was applied. 3The inner needle extrudes the core spinning solution, the middle needle delivers deionized water, and the outer needle extrudes the outer spinning solution. The extrusion flow rate of the core spinning solution is 1 mL / h, the extrusion flow rate of the deionized water is 4 mL / h, and the extrusion flow rate of the outer spinning solution is 2 mL / h. The stretching speed is adjusted to 500 mm / min, the coagulation bath temperature to 42℃, and the ambient humidity to 20% RH to induce the formation of a large pitch (3 mm) helical structure. The nascent fiber is oxidized and cured in 0.5% H2O2 solution for 1 hour, heat-annealed at 80℃ for 30 minutes, and then soaked in deionized water for 48 hours to shape the outer TPU layer. Finally, it is dried for 24 hours to obtain the finished fiber, which is a temperature sensing fiber resistant to strain interference.

[0064] The morphology and structure of the strain-resistant temperature-sensing fiber prepared in this embodiment were tested. The surface and cross-section of the fiber were observed using a desktop scanning electron microscope, revealing a clearly visible helical structure within the fiber. Figure 3 As shown, the inner fibers curl and attach to the outermost layer, the spiral fibers and outer microtubules fuse together, and a spiral trajectory is displayed on the surface.

[0065] Example 2

[0066] This embodiment provides a method for preparing a temperature sensing fiber resistant to strain interference, comprising the following steps:

[0067] S1: Preparation of outer TPU solution: Accurately measure 15ml of LDMF as solvent, add 3.50g of TPU particles, stir on a magnetic stirrer until completely dissolved, then add 0.18g of phenylboronic acid, stir magnetically until completely dissolved, to form a uniform and transparent outer spinning solution.

[0068] S2: Preparation of core layer CNT / TPU composite spinning solution: 10 mL of LDM and 1 mL of anhydrous ethanol were measured sequentially as a mixed solvent, 0.94 g of TPU particles were added, and after pre-stirring for 3 hours, 0.05 g of multi-walled carbon nanotubes (MWCNTs) were added, with a CNT mass fraction of 0.40%. Simultaneously, 0.06 g of diacrylate disulfide (DSDA, accounting for 6% of the TPU mass) and 0.002 g of dibutyltin dilaurate catalyst were added. After stirring for another 5 hours, ultrasonic treatment was performed for 30 minutes to obtain a black inner layer spinning solution containing a dynamic disulfide bond network, i.e., core layer spinning solution.

[0069] S3: Fiber Preparation: A wet spinning device with three coaxial needles was used, employing 22G / 17G / 13G coaxial needles (inner diameters of 0.4mm / 1.05mm / 1.9mm). The entire three-layer needle assembly was immersed in the conductive medium (25℃ deionized water) of an ultrasonic cleaner. Simultaneously with fiber extrusion and coagulation, 40kHz ultrasonic irradiation (power density 0.5W / cm³) was applied. 3The inner needle extrudes the core spinning solution, the middle needle delivers deionized water, and the outer needle extrudes the outer spinning solution. The extrusion flow rate of the core spinning solution is 2 mL / h, the extrusion flow rate of the deionized water is 4 mL / h, and the extrusion flow rate of the outer spinning solution is 2 mL / h. The stretching speed is adjusted to 250 mm / min, the coagulation bath temperature to 42℃, and the ambient humidity to 20% RH to induce the formation of a small pitch (1 mm) helical structure. The nascent fiber is oxidized and cured in 0.5% H2O2 solution for 1 hour, heat-annealed at 80℃ for 30 minutes, and then soaked in deionized water for 48 hours to shape the outer TPU layer. Finally, it is dried for 24 hours to obtain the finished fiber, which is a temperature sensing fiber resistant to strain interference.

[0070] Example 3

[0071] This embodiment provides a method for preparing a temperature sensing fiber resistant to strain interference, comprising the following steps:

[0072] S1: Preparation of outer TPU solution: Accurately measure 15ml of LDMF as solvent, add 3.50g of TPU particles, stir on a magnetic stirrer until completely dissolved, then add 0.18g of phenylboronic acid, stir magnetically until completely dissolved, to form a uniform and transparent outer spinning solution.

[0073] S2: Preparation of core layer CNT / TPU composite spinning solution: 10 mL of LDM and 1 mL of anhydrous ethanol were measured sequentially as a mixed solvent, 0.94 g of TPU particles were added, and after pre-stirring for 3 hours, 0.07 g of multi-walled carbon nanotubes (MWCNTs) were added, with a CNT mass fraction of 0.55%. Simultaneously, 0.06 g of diacrylate disulfide (DSDA, accounting for 6% of the TPU mass) and 0.002 g of dibutyltin dilaurate catalyst were added. After stirring for another 5 hours, ultrasonic treatment was performed for 30 minutes to obtain a black inner layer spinning solution containing a dynamic disulfide bond network, i.e., core layer spinning solution.

[0074] S3: Fiber Preparation: A wet spinning device with three coaxial needles was used, employing 22G / 17G / 13G coaxial needles (inner diameters of 0.4mm / 1.05mm / 1.9mm). The entire three-layer needle assembly was immersed in the conductive medium (25℃ deionized water) of an ultrasonic cleaner. Simultaneously with fiber extrusion and coagulation, 40kHz ultrasonic irradiation (power density 0.5W / cm³) was applied. 3The inner needle extrudes the core spinning solution, the middle needle delivers deionized water, and the outer needle extrudes the outer spinning solution. The extrusion flow rate of the core spinning solution is 1 mL / h, the extrusion flow rate of the deionized water is 4 mL / h, and the extrusion flow rate of the outer spinning solution is 2 mL / h. The stretching speed is adjusted to 500 mm / min, the coagulation bath temperature to 42℃, and the ambient humidity to 20% RH to induce the formation of a large pitch (3 mm) helical structure. The nascent fiber is oxidized and cured in 0.5% H2O2 solution for 1 hour, heat-annealed at 80℃ for 30 minutes, and then soaked in deionized water for 48 hours to shape the outer TPU layer. Finally, it is dried for 24 hours to obtain the finished fiber, which is a temperature sensing fiber resistant to strain interference.

[0075] Example 4

[0076] This embodiment provides a method for preparing a temperature sensing fiber resistant to strain interference, comprising the following steps:

[0077] S1: Preparation of outer TPU solution: Accurately measure 15ml of LDMF as solvent, add 3.50g of TPU particles, stir on a magnetic stirrer until completely dissolved, then add 0.18g of phenylboronic acid, stir magnetically until completely dissolved, to form a uniform and transparent outer spinning solution.

[0078] S2: Preparation of core layer CNT / TPU composite spinning solution: 10 mL of LDM and 1 mL of anhydrous ethanol were measured sequentially as a mixed solvent, 0.94 g of TPU particles were added, and after pre-stirring for 3 hours, 0.07 g of multi-walled carbon nanotubes (MWCNTs) were added, with a CNT mass fraction of 0.55%. Simultaneously, 0.06 g of diacrylate disulfide (DSDA, accounting for 6% of the TPU mass) and 0.002 g of dibutyltin dilaurate catalyst were added. After stirring for another 5 hours, ultrasonic treatment was performed for 30 minutes to obtain a black inner layer spinning solution containing a dynamic disulfide bond network, i.e., core layer spinning solution.

[0079] S3: Fiber Preparation: A wet spinning device with three coaxial needles was used, employing 22G / 17G / 13G coaxial needles (inner diameters of 0.4mm / 1.05mm / 1.9mm). The entire three-layer needle assembly was immersed in the conductive medium (25℃ deionized water) of an ultrasonic cleaner. Simultaneously with fiber extrusion and coagulation, 40kHz ultrasonic irradiation (power density 0.5W / cm³) was applied. 3The inner needle extrudes the core spinning solution, the middle needle delivers deionized water, and the outer needle extrudes the outer spinning solution. The extrusion flow rate of the core spinning solution is 2 mL / h, the extrusion flow rate of the deionized water is 4 mL / h, and the extrusion flow rate of the outer spinning solution is 2 mL / h. The stretching speed is adjusted to 250 mm / min, the coagulation bath temperature to 42℃, and the ambient humidity to 20% RH to induce the formation of a small pitch (1 mm) helical structure. The nascent fiber is oxidized and cured in 0.5% H2O2 solution for 1 hour, heat-annealed at 80℃ for 30 minutes, and then soaked in deionized water for 48 hours to shape the outer TPU layer. Finally, it is dried for 24 hours to obtain the finished fiber, which is a temperature sensing fiber resistant to strain interference.

[0080] Example 5

[0081] This embodiment provides a method for preparing a temperature sensing fiber resistant to strain interference, comprising the following steps:

[0082] S1: Preparation of outer TPU solution: Accurately measure 15ml of LDMF as solvent, add 3.50g of TPU particles, stir on a magnetic stirrer until completely dissolved, then add 0.18g of phenylboronic acid, stir magnetically until completely dissolved, to form a uniform and transparent outer spinning solution.

[0083] S2: Preparation of core layer CNT / TPU composite spinning solution: 10 mL of LDM and 1 mL of anhydrous ethanol were measured sequentially as a mixed solvent, 0.94 g of TPU particles were added, and after pre-stirring for 3 hours, 0.10 g of multi-walled carbon nanotubes (MWCNTs) were added, with a CNT mass fraction of 0.83%. Simultaneously, 0.06 g of diacrylate disulfide (DSDA, accounting for 6% of the TPU mass) and 0.002 g of dibutyltin dilaurate catalyst were added. After stirring for another 5 hours, ultrasonic treatment was performed for 30 minutes to obtain a black inner layer spinning solution containing a dynamic disulfide bond network, i.e., core layer spinning solution.

[0084] S3: Fiber Preparation: A wet spinning device with three coaxial needles was used, employing 22G / 17G / 13G coaxial needles (inner diameters of 0.4mm / 1.05mm / 1.9mm). The entire three-layer needle assembly was immersed in the conductive medium (25℃ deionized water) of an ultrasonic cleaner. Simultaneously with fiber extrusion and coagulation, 40kHz ultrasonic irradiation (power density 0.5W / cm³) was applied. 3The inner needle extrudes the core spinning solution, the middle needle delivers deionized water, and the outer needle extrudes the outer spinning solution. The extrusion flow rate of the core spinning solution is 1 mL / h, the extrusion flow rate of the deionized water is 4 mL / h, and the extrusion flow rate of the outer spinning solution is 2 mL / h. The stretching speed is adjusted to 500 mm / min, the coagulation bath temperature to 42℃, and the ambient humidity to 20% RH to induce the formation of a large pitch (3 mm) helical structure. The nascent fiber is oxidized and cured in 0.5% H2O2 solution for 1 hour, heat-annealed at 80℃ for 30 minutes, and then soaked in deionized water for 48 hours to shape the outer TPU layer. Finally, it is dried for 24 hours to obtain the finished fiber, which is a temperature sensing fiber resistant to strain interference.

[0085] Example 6

[0086] This embodiment provides a method for preparing a temperature sensing fiber resistant to strain interference, comprising the following steps:

[0087] S1: Preparation of outer TPU solution: Accurately measure 15ml of LDMF as solvent, add 3.50g of TPU particles, stir on a magnetic stirrer until completely dissolved, then add 0.18g of phenylboronic acid, stir magnetically until completely dissolved, to form a uniform and transparent outer spinning solution.

[0088] S2: Preparation of core layer CNT / TPU composite spinning solution: 10 mL of LDM and 1 mL of anhydrous ethanol were measured sequentially as a mixed solvent, 0.94 g of TPU particles were added, and after pre-stirring for 3 hours, 0.10 g of multi-walled carbon nanotubes (MWCNTs) were added, with a CNT mass fraction of 0.83%. Simultaneously, 0.06 g of diacrylate disulfide (DSDA, accounting for 6% of the TPU mass) and 0.002 g of dibutyltin dilaurate catalyst were added. After stirring for another 5 hours, ultrasonic treatment was performed for 30 minutes to obtain a black inner layer spinning solution containing a dynamic disulfide bond network, i.e., core layer spinning solution.

[0089] S3: Fiber Preparation: A wet spinning device with three coaxial needles was used, employing 22G / 17G / 13G coaxial needles (inner diameters of 0.4mm / 1.05mm / 1.9mm). The entire three-layer needle assembly was immersed in the conductive medium (25℃ deionized water) of an ultrasonic cleaner. Simultaneously with fiber extrusion and coagulation, 40kHz ultrasonic irradiation (power density 0.5W / cm³) was applied. 3The inner needle extrudes the core spinning solution, the middle needle delivers deionized water, and the outer needle extrudes the outer spinning solution. The extrusion flow rate of the core spinning solution is 2 mL / h, the extrusion flow rate of the deionized water is 4 mL / h, and the extrusion flow rate of the outer spinning solution is 2 mL / h. The stretching speed is adjusted to 250 mm / min, the coagulation bath temperature to 42℃, and the ambient humidity to 20% RH to induce the formation of a small pitch (1 mm) helical structure. The nascent fiber is oxidized and cured in 0.5% H2O2 solution for 1 hour, annealed at 80℃ for 30 minutes, and then soaked in deionized water for 48 hours to shape the outer TPU layer. Finally, it is dried for 24 hours to obtain the finished fiber, which is a temperature sensing fiber resistant to strain interference.

[0090] Example 7

[0091] This embodiment provides a method for preparing a temperature sensing fiber resistant to strain interference, comprising the following steps:

[0092] S1: Preparation of outer TPU solution: Accurately measure 15ml of LDMF as solvent, add 3.50g of TPU particles, stir on a magnetic stirrer until completely dissolved, then add 0.18g of phenylboronic acid, stir magnetically until completely dissolved, to form a uniform and transparent outer spinning solution.

[0093] S2: Preparation of core layer CNT / TPU composite spinning solution: 10 mL of LDM and 1 mL of anhydrous ethanol were measured sequentially as mixed solvents, 0.94 g of TPU particles were added, and after pre-stirring for 3 hours, 0.13 g of multi-walled carbon nanotubes (MWCNTs) were added, with a CNT mass fraction of 1.08%. Simultaneously, 0.06 g of diacrylate disulfide (DSDA, accounting for 6% of the TPU mass) and 0.002 g of dibutyltin dilaurate catalyst were added. After stirring for another 5 hours, ultrasonic treatment was performed for 30 minutes to obtain a black inner layer spinning solution containing a dynamic disulfide bond network, i.e., core layer spinning solution.

[0094] S3: Fiber Preparation: A wet spinning device with three coaxial needles was used, employing 22G / 17G / 13G coaxial needles (inner diameters of 0.4mm / 1.05mm / 1.9mm). The entire three-layer needle assembly was immersed in the conductive medium (25℃ deionized water) of an ultrasonic cleaner. Simultaneously with fiber extrusion and coagulation, 40kHz ultrasonic irradiation (power density 0.5W / cm³) was applied. 3The inner needle extrudes the core spinning solution, the middle needle delivers deionized water, and the outer needle extrudes the outer spinning solution. The extrusion flow rate of the core spinning solution is 1 mL / h, the extrusion flow rate of the deionized water is 4 mL / h, and the extrusion flow rate of the outer spinning solution is 2 mL / h. The stretching speed is adjusted to 500 mm / min, the coagulation bath temperature to 42℃, and the ambient humidity to 20% RH to induce the formation of a large pitch (3 mm) helical structure. The nascent fiber is oxidized and cured in 0.5% H2O2 solution for 1 hour, heat-annealed at 80℃ for 30 minutes, and then soaked in deionized water for 48 hours to shape the outer TPU layer. Finally, it is dried for 24 hours to obtain the finished fiber, which is a temperature sensing fiber resistant to strain interference.

[0095] Example 8

[0096] This embodiment provides a method for preparing a temperature sensing fiber resistant to strain interference, comprising the following steps:

[0097] S1: Preparation of outer TPU solution: Accurately measure 15ml of LDMF as solvent, add 3.50g of TPU particles, stir on a magnetic stirrer until completely dissolved, then add 0.18g of phenylboronic acid, stir magnetically until completely dissolved, to form a uniform and transparent outer spinning solution.

[0098] S2: Preparation of core layer CNT / TPU composite spinning solution: 10 mL of LDM and 1 mL of anhydrous ethanol were measured sequentially as mixed solvents, 0.94 g of TPU particles were added, and after pre-stirring for 3 hours, 0.13 g of multi-walled carbon nanotubes (MWCNTs) were added, with a CNT mass fraction of 1.08%. Simultaneously, 0.06 g of diacrylate disulfide (DSDA, accounting for 6% of the TPU mass) and 0.002 g of dibutyltin dilaurate catalyst were added. After stirring for another 5 hours, ultrasonic treatment was performed for 30 minutes to obtain a black inner layer spinning solution containing a dynamic disulfide bond network, i.e., core layer spinning solution.

[0099] S3: Fiber Preparation: A wet spinning device with three coaxial needles was used, employing 22G / 17G / 13G coaxial needles (inner diameters of 0.4mm / 1.05mm / 1.9mm). The entire three-layer needle assembly was immersed in the conductive medium (25℃ deionized water) of an ultrasonic cleaner. Simultaneously with fiber extrusion and coagulation, 40kHz ultrasonic irradiation (power density 0.8W / cm³) was applied. 3The inner needle extrudes the core spinning solution, the middle needle delivers deionized water, and the outer needle extrudes the outer spinning solution. The extrusion flow rate of the core spinning solution is 2 mL / h, the extrusion flow rate of the deionized water is 4 mL / h, and the extrusion flow rate of the outer spinning solution is 2 mL / h. The stretching speed is adjusted to 250 mm / min, the coagulation bath temperature to 42℃, and the ambient humidity to 20% RH to induce the formation of a small pitch (1 mm) helical structure. The nascent fiber is oxidized and cured in 0.5% H2O2 solution for 1 hour, heat-annealed at 80℃ for 30 minutes, and then soaked in deionized water for 48 hours to shape the outer TPU layer. Finally, it is dried for 24 hours to obtain the finished fiber, which is a temperature sensing fiber resistant to strain interference.

[0100] Example 9

[0101] This embodiment provides a method for preparing a temperature sensing fiber resistant to strain interference, comprising the following steps:

[0102] S1: Preparation of outer TPU solution: Accurately measure 15ml of LDMF as solvent, add 3.50g of TPU particles, stir on a magnetic stirrer until completely dissolved, then add 0.18g of phenylboronic acid, stir magnetically until completely dissolved, to form a uniform and transparent outer spinning solution.

[0103] S2: Preparation of core layer CNT / TPU composite spinning solution: 10 mL of LDM and 1 mL of anhydrous ethanol were measured sequentially as a mixed solvent, 0.94 g of TPU particles were added, and after pre-stirring for 3 hours, 0.15 g of multi-walled carbon nanotubes (MWCNTs) were added, with a CNT mass fraction of 1.23%. Simultaneously, 0.06 g of diacrylate disulfide (DSDA, accounting for 6% of the TPU mass) and 0.002 g of dibutyltin dilaurate catalyst were added. After stirring for another 5 hours, ultrasonic treatment was performed for 30 minutes to obtain a black inner layer spinning solution containing a dynamic disulfide bond network, i.e., core layer spinning solution.

[0104] S3: Fiber Preparation: A wet spinning device with three coaxial needles was used, employing 22G / 17G / 13G coaxial needles (inner diameters of 0.4mm / 1.05mm / 1.9mm). The entire three-layer needle assembly was immersed in the conductive medium (25℃ deionized water) of an ultrasonic cleaner. Simultaneously with fiber extrusion and coagulation, 40kHz ultrasonic irradiation (power density 0.8W / cm³) was applied. 3The inner needle extrudes the core spinning solution, the middle needle delivers deionized water, and the outer needle extrudes the outer spinning solution. The extrusion flow rate of the core spinning solution is 1 mL / h, the extrusion flow rate of the deionized water is 4 mL / h, and the extrusion flow rate of the outer spinning solution is 2 mL / h. The stretching speed is adjusted to 500 mm / min, the coagulation bath temperature to 42℃, and the ambient humidity to 20% RH to induce the formation of a large pitch (3 mm) helical structure. The nascent fiber is oxidized and cured in 0.5% H2O2 solution for 1 hour, heat-annealed at 80℃ for 30 minutes, and then soaked in deionized water for 48 hours to shape the outer TPU layer. Finally, it is dried for 24 hours to obtain the finished fiber, which is a temperature sensing fiber resistant to strain interference.

[0105] Example 10

[0106] This embodiment provides a method for preparing a temperature sensing fiber resistant to strain interference, comprising the following steps:

[0107] S1: Preparation of outer TPU solution: Accurately measure 15ml of LDMF as solvent, add 3.50g of TPU particles, stir on a magnetic stirrer until completely dissolved, then add 0.18g of phenylboronic acid, stir magnetically until completely dissolved, to form a uniform and transparent outer spinning solution.

[0108] S2: Preparation of core layer CNT / TPU composite spinning solution: 10 mL of LDM and 1 mL of anhydrous ethanol were measured sequentially as a mixed solvent, 0.94 g of TPU particles were added, and after pre-stirring for 3 hours, 0.15 g of multi-walled carbon nanotubes (MWCNTs) were added, with a CNT mass fraction of 1.23%. Simultaneously, 0.06 g of diacrylate disulfide (DSDA, accounting for 6% of the TPU mass) and 0.002 g of dibutyltin dilaurate catalyst were added. After stirring for another 5 hours, ultrasonic treatment was performed for 30 minutes to obtain a black inner layer spinning solution containing a dynamic disulfide bond network, i.e., core layer spinning solution.

[0109] S3: Fiber Preparation: A wet spinning device with three coaxial needles was used, employing 22G / 17G / 13G coaxial needles (inner diameters of 0.4mm / 1.05mm / 1.9mm). The entire three-layer needle assembly was immersed in the conductive medium (25℃ deionized water) of an ultrasonic cleaner. Simultaneously with fiber extrusion and coagulation, 40kHz ultrasonic irradiation (power density 0.8W / cm³) was applied. 3The inner needle extrudes the core spinning solution, the middle needle delivers deionized water, and the outer needle extrudes the outer spinning solution. The extrusion flow rate of the core spinning solution is 2 mL / h, the extrusion flow rate of the deionized water is 4 mL / h, and the extrusion flow rate of the outer spinning solution is 2 mL / h. The stretching speed is adjusted to 250 mm / min, the coagulation bath temperature to 42℃, and the ambient humidity to 20% RH to induce the formation of a small pitch (1 mm) helical structure. The nascent fiber is oxidized and cured in 0.5% H2O2 solution for 1 hour, heat-annealed at 80℃ for 30 minutes, and then soaked in deionized water for 48 hours to shape the outer TPU layer. Finally, it is dried for 24 hours to obtain the finished fiber, which is a temperature sensing fiber resistant to strain interference.

[0110] Example 11

[0111] This embodiment provides a method for preparing a temperature sensing fiber resistant to strain interference, comprising the following steps:

[0112] S1: Preparation of outer TPU solution: Accurately measure 15ml of LDMF as solvent, add 3.50g of TPU particles, stir on a magnetic stirrer until completely dissolved, then add 0.18g of phenylboronic acid, stir magnetically until completely dissolved, to form a uniform and transparent outer spinning solution.

[0113] S2: Preparation of core layer CNT / TPU composite spinning solution: 10 mL of LDM and 1 mL of anhydrous ethanol were measured sequentially as a mixed solvent, 0.94 g of TPU particles were added, and after pre-stirring for 3 hours, 0.17 g of multi-walled carbon nanotubes (MWCNTs) were added, with a CNT mass fraction of 1.40%. Simultaneously, 0.06 g of diacrylate disulfide (DSDA, accounting for 6% of the TPU mass) and 0.002 g of dibutyltin dilaurate catalyst were added. After stirring for another 5 hours, ultrasonic treatment was performed for 30 minutes to obtain a black inner layer spinning solution containing a dynamic disulfide bond network, i.e., core layer spinning solution.

[0114] S3: Fiber Preparation: A wet spinning device with three coaxial needles was used, employing 22G / 17G / 13G coaxial needles (inner diameters of 0.4mm / 1.05mm / 1.9mm). The entire three-layer needle assembly was immersed in the conductive medium (25℃ deionized water) of an ultrasonic cleaner. Simultaneously with fiber extrusion and coagulation, 40kHz ultrasonic irradiation (power density 0.8W / cm³) was applied. 3The inner needle extrudes the core spinning solution, the middle needle delivers deionized water, and the outer needle extrudes the outer spinning solution. The extrusion flow rate of the core spinning solution is 1 mL / h, the extrusion flow rate of the deionized water is 4 mL / h, and the extrusion flow rate of the outer spinning solution is 2 mL / h. The stretching speed is adjusted to 500 mm / min, the coagulation bath temperature to 42℃, and the ambient humidity to 20% RH to induce the formation of a large pitch (3 mm) helical structure. The nascent fiber is oxidized and cured in 0.5% H2O2 solution for 1 hour, heat-annealed at 80℃ for 30 minutes, and then soaked in deionized water for 48 hours to shape the outer TPU layer. Finally, it is dried for 24 hours to obtain the finished fiber, which is a temperature sensing fiber resistant to strain interference.

[0115] Example 12

[0116] This embodiment provides a method for preparing a temperature sensing fiber resistant to strain interference, comprising the following steps:

[0117] S1: Preparation of outer TPU solution: Accurately measure 15ml of LDMF as solvent, add 3.50g of TPU particles, stir on a magnetic stirrer until completely dissolved, then add 0.18g of phenylboronic acid, stir magnetically until completely dissolved, to form a uniform and transparent outer spinning solution.

[0118] S2: Preparation of core layer CNT / TPU composite spinning solution: 10 mL of LDM and 1 mL of anhydrous ethanol were measured sequentially as a mixed solvent, 0.94 g of TPU particles were added, and after pre-stirring for 3 hours, 0.17 g of multi-walled carbon nanotubes (MWCNTs) were added, with a CNT mass fraction of 1.40%. Simultaneously, 0.06 g of diacrylate disulfide (DSDA, accounting for 6% of the TPU mass) and 0.002 g of dibutyltin dilaurate catalyst were added. After stirring for another 5 hours, ultrasonic treatment was performed for 30 minutes to obtain a black inner layer spinning solution containing a dynamic disulfide bond network, i.e., core layer spinning solution.

[0119] S3: Fiber Preparation: A wet spinning device with three coaxial needles was used, employing 22G / 17G / 13G coaxial needles (inner diameters of 0.4mm / 1.05mm / 1.9mm). The entire three-layer needle assembly was immersed in the conductive medium (25℃ deionized water) of an ultrasonic cleaner. Simultaneously with fiber extrusion and coagulation, 40kHz ultrasonic irradiation (power density 0.8W / cm³) was applied. 3The inner needle extrudes the core spinning solution, the middle needle delivers deionized water, and the outer needle extrudes the outer spinning solution. The extrusion flow rate of the core spinning solution is 2 mL / h, the extrusion flow rate of the deionized water is 4 mL / h, and the extrusion flow rate of the outer spinning solution is 2 mL / h. The stretching speed is adjusted to 250 mm / min, the coagulation bath temperature to 42℃, and the ambient humidity to 20% RH to induce the formation of a small pitch (1 mm) helical structure. The nascent fiber is oxidized and cured in 0.5% H2O2 solution for 1 hour, heat-annealed at 80℃ for 30 minutes, and then soaked in deionized water for 48 hours to shape the outer TPU layer. Finally, it is dried for 24 hours to obtain the finished fiber, which is a temperature sensing fiber resistant to strain interference.

[0120] Comparative Example 1

[0121] This comparative example provides a method for preparing a temperature sensing fiber resistant to strain interference, comprising the following steps:

[0122] S1: Preparation of outer TPU solution: Accurately measure 15ml of LDMF as solvent, add 3.50g of TPU particles, stir on a magnetic stirrer until completely dissolved, then add 0.18g of phenylboronic acid, stir magnetically until completely dissolved, to form a uniform and transparent outer spinning solution.

[0123] S2: Preparation of core layer CNT / TPU composite spinning solution: 10 mL of LDM and 1 mL of anhydrous ethanol were measured sequentially as a mixed solvent, 0.94 g of TPU particles were added, and after pre-stirring for 3 hours, 0.05 g of multi-walled carbon nanotubes (MWCNTs) were added, with a CNT mass fraction of 0.40%. Simultaneously, 0.06 g of diacrylate disulfide (DSDA, accounting for 6% of the TPU mass) and 0.002 g of dibutyltin dilaurate catalyst were added. After stirring for another 5 hours, ultrasonic treatment was performed for 30 minutes to obtain a black inner layer spinning solution containing a dynamic disulfide bond network, i.e., core layer spinning solution.

[0124] S3: Fiber Preparation: Using a 22G / 17G coaxial needle (inner diameter 0.4mm / 1.05mm), the entire needle assembly was immersed in the conductive medium (25℃ deionized water) of an ultrasonic cleaner. Simultaneously, 40kHz ultrasonic irradiation (power density 0.5W / cm³) was applied while the fiber was extruded and solidified. 3 The inner needle extrudes the core spinning solution, and the outer needle extrudes the outer spinning solution. The extrusion flow rate of the core spinning solution is 5 mL / h, and the extrusion flow rate of the outer spinning solution is 10 mL / h. The stretching speed is adjusted to 300 mm / min, the coagulation bath temperature to 42℃, and the ambient humidity to 20% RH to induce the formation of a pitchless structure. The nascent fiber is oxidized and cured in 0.5% H2O2 solution for 1 hour, annealed at 80℃ for 30 minutes, and then soaked in deionized water for 48 hours to shape the outer TPU layer. Finally, it is dried for 24 hours to obtain the finished fiber, which is a temperature sensing fiber resistant to strain interference.

[0125] Comparative Example 2

[0126] This comparative example provides a method for preparing a temperature sensing fiber resistant to strain interference, comprising the following steps:

[0127] S1: Preparation of outer TPU solution: Accurately measure 15ml of LDMF as solvent, add 3.50g of TPU particles, stir on a magnetic stirrer until completely dissolved, then add 0.18g of phenylboronic acid, stir magnetically until completely dissolved, to form a uniform and transparent outer spinning solution.

[0128] S2: Preparation of core layer CNT / TPU composite spinning solution: 10 mL of LDM and 1 mL of anhydrous ethanol were measured sequentially as a mixed solvent, 0.94 g of TPU particles were added, and after pre-stirring for 3 hours, 0.07 g of multi-walled carbon nanotubes (MWCNTs) were added, with a CNT mass fraction of 0.55%. Simultaneously, 0.06 g of diacrylate disulfide (DSDA, accounting for 6% of the TPU mass) and 0.002 g of dibutyltin dilaurate catalyst were added. After stirring for another 5 hours, ultrasonic treatment was performed for 30 minutes to obtain a black inner layer spinning solution containing a dynamic disulfide bond network, i.e., core layer spinning solution.

[0129] S3: Fiber Preparation: Using a 22G / 17G coaxial needle (inner diameter 0.4mm / 1.05mm), the entire needle assembly was immersed in the conductive medium (25℃ deionized water) of an ultrasonic cleaner. Simultaneously, 40kHz ultrasonic irradiation (power density 0.5W / cm³) was applied while the fiber was extruded and solidified. 3 The inner needle extrudes the core spinning solution, and the outer needle extrudes the outer spinning solution. The extrusion flow rate of the core spinning solution is 5 mL / h, and the extrusion flow rate of the outer spinning solution is 10 mL / h. The stretching speed is adjusted to 300 mm / min, the coagulation bath temperature to 42℃, and the ambient humidity to 20% RH to induce the formation of a pitchless structure. The nascent fiber is oxidized and cured in 0.5% H2O2 solution for 1 hour, annealed at 80℃ for 30 minutes, and then soaked in deionized water for 48 hours to shape the outer TPU layer. Finally, it is dried for 24 hours to obtain the finished fiber, which is a temperature sensing fiber resistant to strain interference.

[0130] Comparative Example 3

[0131] This comparative example provides a method for preparing a temperature sensing fiber resistant to strain interference, comprising the following steps:

[0132] S1: Preparation of outer TPU solution: Accurately measure 15ml of LDMF as solvent, add 3.50g of TPU particles, stir on a magnetic stirrer until completely dissolved, then add 0.18g of phenylboronic acid, stir magnetically until completely dissolved, to form a uniform and transparent outer spinning solution.

[0133] S2: Preparation of core layer CNT / TPU composite spinning solution: 10 mL of LDM and 1 mL of anhydrous ethanol were measured sequentially as a mixed solvent, 0.94 g of TPU particles were added, and after pre-stirring for 3 hours, 0.10 g of multi-walled carbon nanotubes (MWCNTs) were added, with a CNT mass fraction of 0.83%. Simultaneously, 0.06 g of diacrylate disulfide (DSDA, accounting for 6% of the TPU mass) and 0.002 g of dibutyltin dilaurate catalyst were added. After stirring for another 5 hours, ultrasonic treatment was performed for 30 minutes to obtain a black inner layer spinning solution containing a dynamic disulfide bond network, i.e., core layer spinning solution.

[0134] S3: Fiber Preparation: Using a 22G / 17G coaxial needle (inner diameter 0.4mm / 1.05mm), the entire needle assembly was immersed in the conductive medium (25℃ deionized water) of an ultrasonic cleaner. Simultaneously, 40kHz ultrasonic irradiation (power density 0.5W / cm³) was applied while the fiber was extruded and solidified. 3 The inner needle extrudes the core spinning solution, and the outer needle extrudes the outer spinning solution. The extrusion flow rate of the core spinning solution is 5 mL / h, and the extrusion flow rate of the outer spinning solution is 10 mL / h. The stretching speed is adjusted to 300 mm / min, the coagulation bath temperature to 42℃, and the ambient humidity to 20% RH to induce the formation of a pitchless structure. The nascent fiber is oxidized and cured in 0.5% H2O2 solution for 1 hour, annealed at 80℃ for 30 minutes, and then soaked in deionized water for 48 hours to shape the outer TPU layer. Finally, it is dried for 24 hours to obtain the finished fiber, which is a temperature sensing fiber resistant to strain interference.

[0135] Comparative Example 4

[0136] This comparative example provides a method for preparing a temperature sensing fiber resistant to strain interference, comprising the following steps:

[0137] S1: Preparation of outer TPU solution: Accurately measure 15ml of LDMF as solvent, add 3.50g of TPU particles, stir on a magnetic stirrer until completely dissolved, then add 0.18g of phenylboronic acid, stir magnetically until completely dissolved, to form a uniform and transparent outer spinning solution.

[0138] S2: Preparation of core layer CNT / TPU composite spinning solution: 10 mL of LDM and 1 mL of anhydrous ethanol were measured sequentially as mixed solvents, 0.94 g of TPU particles were added, and after pre-stirring for 3 hours, 0.13 g of multi-walled carbon nanotubes (MWCNTs) were added, with a CNT mass fraction of 1.08%. Simultaneously, 0.06 g of diacrylate disulfide (DSDA, accounting for 6% of the TPU mass) and 0.002 g of dibutyltin dilaurate catalyst were added. After stirring for another 5 hours, ultrasonic treatment was performed for 30 minutes to obtain a black inner layer spinning solution containing a dynamic disulfide bond network, i.e., core layer spinning solution.

[0139] S3: Fiber Preparation: Using a 22G / 17G coaxial needle (inner diameter 0.4mm / 1.05mm), the entire needle assembly was immersed in the conductive medium (25℃ deionized water) of an ultrasonic cleaner. Simultaneously, 40kHz ultrasonic irradiation (power density 0.8W / cm³) was applied while the fiber was extruded and solidified. 3 The inner needle extrudes the core spinning solution, and the outer needle extrudes the outer spinning solution. The extrusion flow rate of the core spinning solution is 5 mL / h, and the extrusion flow rate of the outer spinning solution is 10 mL / h. The stretching speed is adjusted to 300 mm / min, the coagulation bath temperature to 42℃, and the ambient humidity to 20% RH to induce the formation of a pitchless structure. The nascent fiber is oxidized and cured in 0.5% H2O2 solution for 1 hour, annealed at 80℃ for 30 minutes, and then soaked in deionized water for 48 hours to shape the outer TPU layer. Finally, it is dried for 24 hours to obtain the finished fiber, which is a temperature sensing fiber resistant to strain interference.

[0140] Comparative Example 5

[0141] This comparative example provides a method for preparing a temperature sensing fiber resistant to strain interference, comprising the following steps:

[0142] S1: Preparation of outer TPU solution: Accurately measure 15ml of LDMF as solvent, add 3.50g of TPU particles, stir on a magnetic stirrer until completely dissolved, then add 0.18g of phenylboronic acid, stir magnetically until completely dissolved, to form a uniform and transparent outer spinning solution.

[0143] S2: Preparation of core layer CNT / TPU composite spinning solution: 10 mL of LDM and 1 mL of anhydrous ethanol were measured sequentially as a mixed solvent, 0.94 g of TPU particles were added, and after pre-stirring for 3 hours, 0.15 g of multi-walled carbon nanotubes (MWCNTs) were added, with a CNT mass fraction of 1.23%. Simultaneously, 0.06 g of diacrylate disulfide (DSDA, accounting for 6% of the TPU mass) and 0.002 g of dibutyltin dilaurate catalyst were added. After stirring for another 5 hours, ultrasonic treatment was performed for 30 minutes to obtain a black inner layer spinning solution containing a dynamic disulfide bond network, i.e., core layer spinning solution.

[0144] S3: Fiber Preparation: Using a 22G / 17G coaxial needle (inner diameter 0.4mm / 1.05mm), the entire needle assembly was immersed in the conductive medium (25℃ deionized water) of an ultrasonic cleaner. Simultaneously, 40kHz ultrasonic irradiation (power density 0.8W / cm³) was applied while the fiber was extruded and solidified. 3The inner needle extrudes the core spinning solution, and the outer needle extrudes the outer spinning solution. The extrusion flow rate of the core spinning solution is 5 mL / h, and the extrusion flow rate of the outer spinning solution is 10 mL / h. The stretching speed is adjusted to 300 mm / min, the coagulation bath temperature to 42℃, and the ambient humidity to 20% RH to induce the formation of a pitchless structure. The nascent fiber is oxidized and cured in 0.5% H2O2 solution for 1 hour, annealed at 80℃ for 30 minutes, and then soaked in deionized water for 48 hours to shape the outer TPU layer. Finally, it is dried for 24 hours to obtain the finished fiber, which is a temperature sensing fiber resistant to strain interference.

[0145] Comparative Example 6

[0146] This comparative example provides a method for preparing a temperature sensing fiber resistant to strain interference, comprising the following steps:

[0147] S1: Preparation of outer TPU solution: Accurately measure 15ml of LDMF as solvent, add 3.50g of TPU particles, stir on a magnetic stirrer until completely dissolved, then add 0.18g of phenylboronic acid, stir magnetically until completely dissolved, to form a uniform and transparent outer spinning solution.

[0148] S2: Preparation of core layer CNT / TPU composite spinning solution: 10 mL of LDM and 1 mL of anhydrous ethanol were measured sequentially as a mixed solvent, 0.94 g of TPU particles were added, and after pre-stirring for 3 hours, 0.17 g of multi-walled carbon nanotubes (MWCNTs) were added, with a CNT mass fraction of 1.40%. Simultaneously, 0.06 g of diacrylate disulfide (DSDA, accounting for 6% of the TPU mass) and 0.002 g of dibutyltin dilaurate catalyst were added. After stirring for another 5 hours, ultrasonic treatment was performed for 30 minutes to obtain a black inner layer spinning solution containing a dynamic disulfide bond network, i.e., core layer spinning solution.

[0149] S3: Fiber Preparation: Using a 22G / 17G coaxial needle (inner diameter 0.4mm / 1.05mm), the entire needle assembly was immersed in the conductive medium (25℃ deionized water) of an ultrasonic cleaner. Simultaneously, 40kHz ultrasonic irradiation (power density 0.8W / cm³) was applied while the fiber was extruded and solidified. 3 The inner needle extrudes the core spinning solution, and the outer needle extrudes the outer spinning solution. The extrusion flow rate of the core spinning solution is 5 mL / h, and the extrusion flow rate of the outer spinning solution is 10 mL / h. The stretching speed is adjusted to 300 mm / min, the coagulation bath temperature to 42℃, and the ambient humidity to 20% RH to induce the formation of a pitchless structure. The nascent fiber is oxidized and cured in 0.5% H2O2 solution for 1 hour, annealed at 80℃ for 30 minutes, and then soaked in deionized water for 48 hours to shape the outer TPU layer. Finally, it is dried for 24 hours to obtain the finished fiber, which is a temperature sensing fiber resistant to strain interference.

[0150] The strain resistance of the temperature sensing fibers prepared in the above embodiments and comparative examples was tested:

[0151] Using a self-assembly push-pull test platform, the temperature sensing properties of the fiber were measured while different strains were applied. The prepared fiber was subjected to multiple stretch-release cycles at 20%, 50%, and 100% strain at a speed of 900 mm / min.

[0152] like Figure 4 As shown, at a low strain level (20% strain), the large pitch fiber... The fluctuation amplitude is relatively moderate, while the fluctuation amplitude of small-pitch fibers is slightly larger, indicating that the internal structure of large-pitch fibers is more advantageous in suppressing resistance changes and has better strain resistance. When entering a medium strain level (50% strain), the large-pitch fibers... The degree of fluctuation and resistance change is higher in large-pitch fibers than in small-pitch fibers. At this point, the structure of small-pitch fibers can more effectively resist the interference of strain on conductivity, exhibiting superior strain resistance. However, at high strain levels (100% strain), large-pitch fibers... The large spikes and extremely drastic fluctuations observed in the large-pitch fibers, compared to the relatively milder fluctuations in the small-pitch fibers, further confirm that small-pitch fibers have a superior strain resistance under high strain conditions. Overall, large-pitch fibers exhibit stronger strain resistance at low strain, while small-pitch fibers are better able to resist the effects of strain on electrical conductivity at medium to high strain.

[0153] Among them, the sensing fiber with a CNT mass fraction of 1.40% has the best resistance to strain interference, with a resistance change rate of less than 6% at 200% strain.

[0154] The temperature sensing performance of the temperature sensing fibers prepared in the above embodiments and comparative examples was tested:

[0155] Using a multi-channel temperature meter and a multimeter, the resistance change of the sensor during the same temperature rise process was measured, and the resistance at different temperatures was recorded. (See [reference needed]). Figure 5 , Figure 6 As shown, the relative resistance changes with different pitches and mass fractions are compared.

[0156] (1) Comparison of different pitches:

[0157] No pitch (green square): At the same temperature, the rate of change of relative resistivity for no pitch remains at a moderate level. Its curve decreases relatively gently, indicating that the rate of change of resistance with temperature is relatively stable for no pitch, and its sensitivity to temperature is relatively moderate.

[0158] Small pitch (purple dot): At all temperature points, the rate of change of relative resistivity is usually the lowest for small pitch. As the temperature increases, the rate of change of relative resistivity decreases significantly, indicating that the resistance is more sensitive to temperature changes under small pitch conditions, and the resistance decreases faster as the temperature rises.

[0159] Large pitch (blue triangle): The relative resistivity change rate is generally the highest at the same temperature for large pitch. The curve drops significantly, especially in the high-temperature region, where the decrease in the relative resistivity change rate is more pronounced, indicating that the resistance is greatly affected by temperature at large pitches, and the resistance decreases more significantly at high temperatures.

[0160] (2) Comparison of quality scores for different CNTs:

[0161] The smaller absolute value of the conductivity slope in the range of 0.40%-0.55% indicates that the resistance changes slowly with temperature. This is because the lower mass fraction of carbon nanotubes results in weaker conductivity. The absolute value of the slope increases with the carbon nanotube content in the range of 1.08%-1.23%, and the relative rate of change in resistance is more significant. At the same time, the resistance changes faster under high temperature (70-120℃) conditions compared to low temperature (30-70℃).

[0162] Temperature performance test for resistance to strain interference:

[0163] Using a multi-channel temperature tester and a multimeter, the resistance change of the temperature sensor during the same heating process was measured, the resistance at different temperatures was recorded, and the relative resistance changes under different stretching states were compared. Figure 7 The study shows the trend of relative resistivity change rate with temperature (°C) under three stretching conditions: 0%, 15%, and 30%. It can be seen that the relative resistivity change rate is not significantly different under the three stretching conditions, demonstrating that the fiber has good resistance to strain disturbance.

[0164] In summary, this application utilizes carbon nanotubes (CNTs) as conductive fillers and thermoplastic polyurethane (TPU) as a flexible matrix material through material selection and proportioning. By precisely controlling the mass fraction of CNTs between 0.40% and 1.40%, a composite material with good electrical conductivity and mechanical properties is prepared. The mass fraction of CNTs has a significant impact on the performance of the sensing fibers; a mass fraction of 0.83%–1.08% achieves a good balance between the fiber's flexibility and strength.

[0165] The structural design of this application adopts a double-layer composite spiral configuration. Utilizing a wet spinning process, by controlling parameters such as the flow rate of the carbon nanotube solution in the core layer and the drawing speed during spinning, the inner CNT conductive layer forms a spiral structure, while the outer layer is a TPU protective layer. The spiral structure design enables physical decoupling of strain and temperature signals, effectively reducing strain interference with temperature measurement. The large-pitch spiral structure exhibits excellent strain resistance under low-strain conditions, while the small-pitch spiral structure is more effective in suppressing strain interference under medium-to-high strain conditions.

[0166] 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.

Claims

1. A temperature sensing fiber resistant to strain interference, characterized in that, It includes a core layer and an outer layer covering the outside of the core layer; the core layer is a conductive layer and has a spiral structure; the outer layer is made of a polymer material. The core layer is prepared by a wet spinning process using a core layer spinning solution; the core layer spinning solution includes conductive filler, thermoplastic polyurethane, functional monomers containing disulfide bonds, and dibutyltin dynamic crosslinking catalyst. The functional monomer containing disulfide bonds is diacrylic acid disulfide; The conductive filler is a carbon nanotube; The outer layer is prepared by a wet spinning process using an outer layer spinning solution; The outer spinning solution includes thermoplastic polyurethane; The outer spinning solution also includes phenylboronic acid.

2. The temperature sensing fiber resistant to strain interference as described in claim 1, characterized in that, The dibutyltin dynamic crosslinking catalyst is dibutyltin dilaurate.

3. The temperature sensing fiber resistant to strain interference as described in claim 1, characterized in that, The conductive filler in the core spinning solution has a mass fraction ranging from 0.40% to 1.40%; the total mass ratio of the thermoplastic polyurethane, the disulfide-containing functional monomer, and the dibutyltin dynamic crosslinking catalyst to the conductive filler is 1:(0.05-0.17); the mass ratio of the disulfide-containing functional monomer to the thermoplastic polyurethane is (5-8):100; and the mass ratio of the dibutyltin dynamic crosslinking catalyst to the thermoplastic polyurethane is (0.1-0.3):

100.

4. The temperature sensing fiber resistant to strain interference as described in claim 1, characterized in that, The pitch of the spiral structure ranges from 1 to 3 mm.

5. A method for preparing a strain-resistant temperature sensing fiber as described in any one of claims 1-4, characterized in that, Includes the following steps: S1: Preparation of outer spinning solution; S2: Preparation of core layer spinning solution; S3: A wet spinning device with three coaxial needles is used. The inner needle extrudes the core spinning solution, the middle needle delivers deionized water, and the outer needle extrudes the outer spinning solution. The extrusion flow rate of the core spinning solution is 1-2 mL / h, the extrusion flow rate of the deionized water is 4 mL / h, and the extrusion flow rate of the outer spinning solution is 2 mL / h. The external drawing speed is 250-500 mm / min. After spinning, the temperature sensing fiber with the highest resistance to strain interference is obtained after preliminary shaping and drying.

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