A micro-gear-shaped special-shaped stretchable conductive radiation-proof fiber and its preparation and application

Abstract

This invention belongs to the field of fiber material technology, and relates to a micro-gear-shaped, stretchable, conductive, and radiation-shielding fiber, its preparation, and application. The fiber is prepared by coaxial wet spinning of a core spinning solution and a shell spinning solution. The core spinning solution is obtained by dissolving TPU in a dispersion of radiation-shielding particles I / II / organic solvent, and the shell spinning solution is obtained by dissolving TPU in an MXene / organic solvent dispersion. The mass-to-volume ratio of TPU to organic solvent in the core spinning solution is 2.2~3g:10ml, and the mass-to-volume ratio of TPU to organic solvent in the shell spinning solution is 0.5~1g:10ml. The radiation-shielding fiber has a core-shell structure, with a circular core cross-section and a micro-gear-shaped shell cross-section, with an average gear protrusion height of 20~50µm. In application, it is processed into a stretchable, multifunctional fabric using a weaving process. This invention uses a coaxial wet spinning process to produce the product in one step; the product has high sensitivity and a wide sensing range; and it has a wide range of applications.

Description

Technical Field

[0001] This invention belongs to the field of fiber material technology, and relates to a micro-gear-shaped, stretchable, conductive, and radiation-shielding fiber, its preparation, and its application. Background Technology

[0002] In recent years, with the rapid development of society and the needs of industrial and defense forces, various electromagnetic technologies have been widely used in both civilian and industrial fields, including wireless communication, medical diagnosis and treatment, and national defense construction. Electromagnetic radiation is divided into two main categories: non-ionizing radiation and ionizing radiation. Ionizing radiation, such as X-rays, has extremely short wavelengths, high energy, and strong penetrating power. It is widely used in fields such as medical radiotherapy, nuclear energy maintenance, and electronic components. Long-term exposure to or contact with X-rays poses a great potential hazard to organisms, which may not only cause DNA damage but also lead to serious health problems such as cancer and genetic mutations. Therefore, the development of radiation protection clothing with high shielding performance is crucial for relevant personnel.

[0003] Studies have shown that currently, in clinical medicine, 80% of interventional procedures involving minimally invasive instruments and real-time medical imaging guidance require continuous X-ray exposure. Workers typically wear 8-10 kg lead aprons while maintaining a forward-leaning posture during surgery. This not only places a heavy burden on the lumbar spine but also significantly impacts worker comfort and joint flexibility. This is because existing protective suits are made from lead wire yarn through weaving and knitting, resulting in high rigidity and less than 30% flexibility. Furthermore, lead is highly toxic, making it unsuitable for skin contact, and its waste causes significant environmental pollution.

[0004] To overcome the above shortcomings, existing technologies have developed lead-free protective clothing. For example, patent application CN119877294A discloses a flexible lead-free X-ray protective coating fabric and its preparation method. This involves mixing bismuth oxide, transparent liquid silicone rubber A, transparent liquid silicone rubber B, and ethyl acetate, then repeatedly coating the mixture onto polyester fabric and curing it to obtain a lead-free X-ray protective fabric suitable for the examinee. This protective coating fabric has the advantages of being non-toxic, lightweight, and soft. However, its radiation-shielding components are singular, resulting in a low X-ray shielding efficiency of only 29.73%. Furthermore, post-treatment of the fabric reduces its comfort and breathability to some extent, making it difficult to meet the required protective effect and comfort requirements during X-ray irradiation. When the fabric stretches following the posture of the human body, the fibers create pores due to the Poisson effect, allowing X-rays to pass through, further reducing the protective effect.

[0005] Furthermore, existing radiation-shielding fibers utilize prestressing methods to create surface wrinkles or microcracks, but their structure is characterized by irregular corrugations, resulting in low sensitivity under tension. For example, the literature (Sensor Actuat A-phys, 2023, 360, 114510) achieves a sensitivity factor (GF) of 136,100 through a two-layer architecture, but this is only within a small strain range of 2%. Patent CN119468899A, through a three-layer membrane structure consisting of a stretchable elastic substrate, a strain-sensitive layer, and a stretchable elastic encapsulation, achieves a strain sensing range of 320%, but the maximum sensitivity is only around 650. Therefore, achieving both high sensing range and high sensitivity simultaneously with fibers remains a significant challenge.

[0006] Therefore, it is of great significance to study a micro-gear-shaped, stretchable, conductive, and radiation-shielding fiber, as well as its preparation and application, in order to solve the problems existing in the current technology. Summary of the Invention

[0007] The purpose of this invention is to solve the problems existing in the prior art and to provide a micro-gear-shaped, stretchable, conductive, and radiation-shielding fiber, as well as its preparation and application.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0009] A method for preparing a micro-gear-shaped, stretchable, conductive, and radiation-shielding fiber involves coaxial wet spinning of the core spinning solution and the shell spinning solution to obtain the micro-gear-shaped, stretchable, conductive, and radiation-shielding fiber.

[0010] The core spinning solution is obtained by dissolving TPU (thermoplastic polyurethane elastomer) in a dispersion of radiation shielding particles I / radiation shielding particles II / organic solvent, and the shell spinning solution is obtained by dissolving TPU in a dispersion of MXene / organic solvent.

[0011] The mass-to-volume ratio of TPU to organic solvent in the core spinning solution is 2.2~3g:10ml, and the mass-to-volume ratio of TPU to organic solvent in the shell spinning solution is 0.5~1g:10ml.

[0012] During coaxial wet spinning, the shell injection rate is 0.08~0.15 ml / min; a shell injection rate less than 0.08 ml / min will result in an excessively thin shell, causing the microgear structure to tend to disappear; a shell injection rate greater than 0.15 ml / min will also be detrimental to the formation of the microgear structure.

[0013] The coagulation bath used in coaxial wet spinning is a mixture of organic solvent, acetic acid, and water, with the organic solvent content in the coagulation bath being 15-20 wt%.

[0014] The core spinning solution, the shell spinning solution, and the organic solvent in the coagulation bath are all selected from one of DMSO, DMF, and DMAC.

[0015] As a preferred technical solution:

[0016] In the preparation method of the micro-gear-shaped irregular stretchable conductive radiation-shielding fiber described above, the content of acetic acid in the coagulation bath is 50~55wt%.

[0017] In the preparation method of the micro-gear-shaped irregular stretchable conductive radiation-shielding fiber described above, during coaxial wet spinning, the inner diameters of the inner and outer needles are 0.4 mm and 1.07 mm, respectively, and the length of the spinning guide tube is 25~30 cm to induce MXene orientation alignment; the core layer injection rate is 0.1~0.3 ml / min. If the core layer injection rate is too high, the core layer components will break through the shell layer, causing leakage.

[0018] The coagulation bath temperature is 25~30℃, and the coagulation bath soaking time is 3~5h. After coagulation and molding, the fiber is first washed with water to remove organic solvents, and then freeze-dried to ensure that the moisture is completely removed and to prevent the collapse of the internal pores and axial protrusions of the fiber.

[0019] The preparation method of the micro-gear-shaped, stretchable, conductive, radiation-shielding fiber described above, the preparation process of the radiation-shielding particle I / radiation-shielding particle II / organic solvent dispersion is as follows: radiation-shielding particle I and radiation-shielding particle II are added sequentially to the organic solvent, and the dispersion is obtained by ultrasonic shearing at 500W for 20 minutes.

[0020] Here, the well-known high-power ultrasonic-shear dispersion method is used. The process parameters of 500W power and 20min are gradually verified in actual operation. Low power dispersion results in a sedimentation rate of more than 40% for high-density radiation-shielding compound particles in organic solvents. At the same time, the processing time of less than 15min will also cause uneven dispersion. The appropriate parameters of 500W and 20min are the best parameter window that can balance stability and purity.

[0021] The method for preparing a micro-gear-shaped, stretchable, conductive, radiation-shielding fiber as described above, wherein radiation-shielding particles I and radiation-shielding particles II are each independently selected from one of bismuth oxide (Bi2O3), tungsten carbide (W2C), barium sulfate (BaSO4), and tantalum pentoxide (Ta2O5); the average particle size of radiation-shielding particles I is 50~90nm, and the average particle size of radiation-shielding particles II is 80~120nm.

[0022] The preparation method of the micro-gear-shaped stretchable conductive radiation-shielding fiber described above, the preparation process of MXene / organic solvent dispersion is as follows: First, Ti3AlC2 powder is added to HCl solution containing LiF and stirred for 24 hours. Then, the reaction mixture is centrifuged and separated, the lower precipitate is retained and repeatedly washed with water until the solution is neutral. Then, the upper liquid is removed by centrifugation using the solvent displacement method, and then organic solvent is added and centrifuged to obtain MXene / organic solvent dispersion.

[0023] The preparation method of the micro-gear-shaped irregular stretchable conductive radiation-shielding fiber described above involves adding Ti3AlC2 powder to a LiF-containing HCl solution (HCl solution concentration is 9M). The concentration of Ti3AlC2 in the mixed solution is 0.04~0.06 g / ml, the concentration of LiF is 0.07~0.09 g / ml, and the concentration of MXene / organic solvent dispersion is 10~18 mg / ml.

[0024] The present invention also provides a micro-gear-shaped stretchable conductive radiation-shielding fiber prepared by the method described in any of the preceding claims, having a core-shell structure, a circular core cross-section, a micro-gear-shaped shell cross-section, and gear protrusions with an average height of 20~50µm and an average width of 10~55µm.

[0025] Both the core substrate and the shell substrate are TPU. The surface of the core substrate has an interwoven micron-sized pore structure, in which radiation-resistant particles I and radiation-resistant particles II are uniformly dispersed. MXene is uniformly dispersed in the shell substrate.

[0026] As a preferred technical solution:

[0027] The micro-gear-shaped, stretchable, conductive, and radiation-shielding fiber described above has an average diameter of 460~500µm and an average shell thickness of 35~40µm.

[0028] The contents of radiation-shielding particles I and II in the core layer are 35.7~56.4wt% and 17.8~25.7wt%, respectively, while the contents of MXene in the shell layer are 12~18wt%.

[0029] The micro-gear-shaped, stretchable, conductive, and radiation-shielding fiber described above exhibits a strain sensitivity range of 0–297% and a sensitivity range of 0–32483. After undergoing 2000 stretching cycles at 0–50% strain, the resistance drift of the micro-gear-shaped, stretchable, conductive, and radiation-shielding fiber is 2–5%, demonstrating the excellent stability of the conductive shell within this strain range. The fiber also exhibits a breaking elongation of 480–530% and an electrical conductivity of 145–280 S / m.

[0030] This invention also provides the application of a micro-gear-shaped, stretchable, conductive, and radiation-shielding fiber as described in any of the preceding claims, which is processed into a stretchable, multifunctional fabric using a weaving process.

[0031] The stretchable multifunctional fabric has a three-layer structure with a warp density of 480~560 threads / 10cm and a weft density of 250~370 threads / 10cm.

[0032] The stretchable multifunctional fabric has an X-ray shielding efficiency of over 90%.

[0033] Invention principle:

[0034] This invention utilizes coaxial wet spinning technology to prepare highly conductive, stretchable, profiled composite fibers in a single step, enabling large-scale mass production. The stretchable, profiled composite fibers prepared by this invention cleverly utilize the heterogeneous shrinkage of two-dimensional MXene and TPU during the wet spinning process, successfully constructing a dense and continuous conductive network on the surface of the radiation-shielding particle I / radiation-shielding particle II / TPU core fiber layer (see...). Figure 2 The fiber exhibits excellent molding with no significant gaps between the core and shell layers, overcoming the problem of existing doped conductive composite fibers struggling to balance high conductivity and mechanical properties. The fiber's interior forms an interwoven, interconnected micron-sized pore structure (see...). Figure 3 A multi-axial protrusion-shaped irregular structure is formed on the surface, thereby producing an X-ray shielding irregular composite fiber with high elongation at break, good flexibility, and high conductivity. The conductive irregular fiber has a larger MXene contact area at the junction of the protrusions and arcs in its cross-section, resulting in a denser conductive network structure. During stretching, this causes more slippage between the conductive MXene components, leading to higher sensitivity. The high concentration of polymer and radiation-shielding particles in the fiber core effectively ensures the fiber's mechanical properties, maintaining good conductivity even under high strain. Therefore, this composite fiber exhibits good conductivity, stability, flexibility, and highly efficient X-ray protection performance.

[0035] The forming mechanism of the micro-gear-shaped, stretchable, conductive, and radiation-shielding fiber in this invention is as follows: When the spinning solution enters the coagulation bath, the shell spinning solution comes into direct contact with the coagulation bath, resulting in solvent displacement between the solvent and the coagulation bath. The high-concentration organic solvent in the spinning solution (relative to the coagulation bath) rapidly penetrates into the coagulation bath, while the non-solvent in the coagulation bath gradually penetrates into the spinning solution, causing TPU phase separation and thus initially forming the fiber shell. The removal of the solvent causes the polymer chain segments to lose the solvation layer, increasing the intermolecular forces and generating shrinkage stress. However, due to the difference in polymer concentration, the low-concentration shell layer (relative to the core layer) generates greater shrinkage stress. After the initial formation of the fiber shell, the high-modulus (≈330 GPa) MXene is sandwiched between the rapidly shrinking thickness direction and the restricted in-plane direction. Under the pressure of the sudden increase in intermolecular forces after solvent removal, it "releases pressure" by stacking and wrinkling, becoming the prototype of the subsequent micro-gear protrusions. With the stacking of MXene sheets, the space allowing liquid to pass through is reduced, thus forming a barrier that hinders the bidirectional diffusion of the solvent, slowing down the entry of the coagulation bath components into the core layer and causing fiber shrinkage. At the same time, the high viscosity and density of the high-concentration TPU / radiation-resistant particle I / radiation-resistant particle II / organic solvent spinning solution in the core layer slows down the outward diffusion of the solvent. As the MXene content increases, the longitudinal conductivity further decreases, resulting in a huge difference in the shrinkage rate between the core and the shell. During the molding process, the shell layer continuously tightens and compresses towards the core layer, stacking to adapt to the slow shrinkage rate of the core layer, forming a micro-gear-shaped irregular structure in the cross section. After the initial phase separation is completed, water molecules and acetic acid in the coagulation bath can only penetrate the micropores on the surface of the nascent fiber shell layer for solvent replacement, slowing down the TPU phase separation rate in the core layer, and gradually forming a dense micron-sized porous structure inward in the core layer.

[0036] Beneficial effects:

[0037] (1) A method for preparing micro-gear-shaped irregular stretchable conductive radiation-shielding fiber of the present invention is to prepare micro-gear-shaped irregular core-shell fiber by coaxial wet spinning, using elastic polymer as substrate, and under the synergistic effect of appropriate spinning process parameters, core-shell substrate ratio and conductive filler ratio, high-performance micro-gear-shaped irregular stretchable conductive radiation-shielding fiber is prepared in one step. The micro-gear structure not only compensates for the reflection loss of X-rays in terms of structure, but also synergistically improves the high sensitivity and tensile stability of fiber material during stretching. It has the characteristics of simple preparation method, controllable structure and mass production capability.

[0038] (2) The preparation method of the micro-gear-shaped stretchable conductive radiation-proof fiber of the present invention not only effectively solves the problem that most lead-free clothing has low radiation protection performance and poor wearability in the prior art, but also provides a basis for realizing large-scale synchronous monitoring and sensing in X-ray environment in medical diagnosis and treatment. The micro-gear-shaped conductive shell improves the attenuation efficiency by extending the ray path and multiple reflections in a synergistic manner.

[0039] (3) The present invention provides a micro gear-shaped, stretchable, conductive, and radiation-resistant fiber. It utilizes a core-shell structure and uses conductive filler MXene to construct an efficient, complete, and stable conductive network. The core-shell interface is tightly bonded and uniformly formed, exhibiting good mechanical tensile properties. The fiber's irregular structure can be easily and economically controlled and produced on a large scale through parameter adjustment. Compared to the method of coating with functional materials, no additional coating is required, and it has better wearing comfort (breathable, wear-resistant, and washable).

[0040] (4) The present invention provides a micro-gear-shaped stretchable conductive radiation-shielding fiber with a larger MXene contact area at the micro-gear-shaped structure of the shell layer and a denser conductive network structure. When stretched, it causes more mutual slippage between the conductive components MXene, resulting in ultra-high sensitivity. Furthermore, the high-concentration polymer in the core layer can provide a high sensing range.

[0041] (5) The present invention provides a micro-gear-shaped, stretchable, conductive, and radiation-resistant fiber. Coaxial wet spinning forms a dense porous structure inside the fiber. Compared with uniaxial spinning, it can obtain loose and porous fiber during multiple stretching, with a reduced resistance change rate and better dynamic stability.

[0042] (6) The present invention provides a micro-gear-shaped, stretchable, conductive, and radiation-shielding fiber. The periodic surface structure of the micro-gear protrusions increases the reflection path of X-rays between the shell MXenes. The doped particles uniformly dispersed in the honeycomb microporous network increase the possibility of X-ray energy dissipation, thereby enhancing the radiation protection performance. At the same time, the structure of the micro-gear protrusions leads to an increase in specific surface area, and the abundant groups and active sites on the MXene surface are more fully exposed, resulting in enhanced reactivity compared to smooth fibers. Further post-processing can be used to achieve functionalization.

[0043] (7) The application of the micro-gear-shaped irregular stretchable conductive radiation-proof fiber of the present invention has a wide range of applications and has great application potential in many fields such as cold-resistant and warm clothing, electric heating products, thermotherapy and health care products, one-way water guide, sensors and capacitors. Attached Figure Description

[0044] Figure 1 This is a surface FE-SEM image of the fiber in Example 1 of the present invention;

[0045] Figure 2 This is a cross-sectional FE-SEM image of the fiber in Example 1 of the present invention;

[0046] Figure 3 This is a magnified FE-SEM cross-section of the fiber in Embodiment 1 of the present invention.

[0047] Figure 4The fiber sensing range and sensitivity GF obtained in Example 1 of this invention; wherein, R 2 It is a statistical index of goodness of fit, representing the degree of linear correlation between changes in resistance and strain. The closer the value is to 1, the closer it is to a linear relationship. Detailed Implementation

[0048] The present invention will be further described below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0049] The test methods involved in the performance indicators in the embodiments and comparative examples of this invention are as follows:

[0050] X-ray shielding efficiency: Tested according to GBZ / T 147-2002. X-ray shielding efficiency is the percentage difference in X-ray dose between the sample-free and sample-added doses relative to the initial measurement. The X-ray tube voltage is set to 130kV, and the filter copper plate thickness is 0.25mm. The X-ray shielding efficiency is calculated using the following formula:

[0051] η=(n0-n d ) / (n0-n b )×100%;

[0052] In the formula: η represents the shielding efficiency against X-rays (%), n0 is the dose rate at initial incidence, and n d n is the dose rate after passing through the sample. b This is the baseline rate.

[0053] Strain sensing range and sensitivity GF: The strain sensing range is the range within which the specimen device can monitor changes in resistance during stretching. Sensitivity is the percentage change in resistance relative to the change in length during stretching. A common measurement method involves clamping copper foil at both ends of the specimen (referring to a single micro-gear-shaped, stretchable, conductive, radiation-shielding fiber) and fixing it to a stretching device, connecting a multimeter to the ohm setting to form a circuit. As the stretching distance gradually increases, the resistance gradually increases until the resistance reading reaches infinity, at which point the test stops. The stretching distance during this process is the strain sensing range. Correspondingly, the sensitivity at a certain strain during stretching can be calculated using the following formula:

[0054] GF = ΔR / (R0*ε);

[0055] ε = ΔL / L0;

[0056] In the formula: GF is the sensitivity; R0 is the initial resistance of the sample; ΔR represents the difference between the resistance under a certain strain and the initial resistance; ε is the strain change; ΔL is the difference between a certain stretching length and the initial length; L0 is the initial length.

[0057] Elongation at break: According to GB / T 14344-2022 standard, a universal tensile testing machine is used to apply tensile strain to the fiber specimen. The gauge length is 10 mm, and the displacement speed is 10 mm / min. As the stretching distance gradually increases, shrinkage will occur in the direction perpendicular to the fiber length due to the Poisson effect until the fiber specimen breaks, at which point the test stops. The strain value corresponding to the break point of the stress-strain curve is the elongation at break.

[0058] Electrical conductivity: According to standard T / SZJL 8-2024, the four-point probe method was used to test a single fiber. The fiber sample was fixed to an insulating substrate, and a constant DC current I was applied along the fiber axis. The voltage drop ΔV was measured. The conductivity was calculated using the following formula:

[0059] σ = L / (R•A);

[0060] R = ΔV / I;

[0061] A=π(D 2 -d 2 ) / 4;

[0062] In the formula: L is the probe spacing, R is the resistance, A is the cross-sectional area of ​​the fiber shell, D is the outer diameter of the fiber, and d is the core diameter.

[0063] The sources of some of the materials in this invention are as follows:

[0064] TPU: Manufacturer: BASF, Brand: 1170A.

[0065] PVA: Manufacturer is Shanghai Aladdin Biochemical Technology Co., Ltd., brand name is 224.

[0066] Example 1

[0067] A method for preparing a micro-gear-shaped, stretchable, conductive, and radiation-shielding fiber, comprising the following specific steps:

[0068] (1) Preparation of raw materials:

[0069] TPU;

[0070] Radiation-resistant particle I: Bismuth oxide (Bi2O3), with an average particle size of 60 nm;

[0071] Radiation protection particles II: tungsten dicarbide (W2C), with an average particle size of 100 nm;

[0072] Organic solvent: dimethyl sulfoxide (DMSO);

[0073] (2) Preparation of Bi2O3 / W2C / DMSO dispersion:

[0074] Bi2O3 and W2C were added to DMSO sequentially, and the mixture was dispersed by ultrasonic shearing to obtain a Bi2O3 / W2C / DMSO dispersion.

[0075] The concentration of Bi2O3 in the Bi2O3 / W2C / DMSO dispersion is 380 mg / ml, and the concentration of W2C is 180 mg / ml.

[0076] (3) Preparation of core spinning solution:

[0077] TPU was dissolved in Bi2O3 / W2C / DMSO dispersion and stirred at 150 rpm for 24 h. After that, the mixture was filtered, sonicated at 100 W for 30 min, and allowed to stand to defoam, to obtain a core spinning solution with a TPU to DMSO mass-volume ratio of 2.5 g: 10 ml.

[0078] (4) Preparation of MXene / DMSO dispersion:

[0079] First, Ti3AlC2 powder was added to an HCl solution containing LiF and stirred at 36°C for 24 hours. Then, the reaction mixture was centrifuged and the lower precipitate was retained and repeatedly washed with water until the solution was neutral. Then, the upper liquid was removed by centrifugation using the solvent displacement method, and DMSO was added and centrifuged to obtain MXene / DMSO dispersion.

[0080] In this mixture, after adding Ti3AlC2 powder to the LiF-containing HCl solution, the concentration of Ti3AlC2 in the mixed solution was 0.05 g / ml, the concentration of LiF was 0.08 g / ml, and the concentration of MXene / DMSO dispersion was 18 mg / ml.

[0081] (5) Preparation of shell spinning solution:

[0082] TPU was dissolved in MXene / DMSO dispersion to obtain a shell spinning solution with a TPU to DMSO mass-volume ratio of 0.85 g: 10 ml;

[0083] (6) The core spinning solution and the shell spinning solution are coaxially wet-spun. After obtaining the nascent fiber through the coagulation bath, the nascent fiber is placed in deionized water for 12 hours, then taken out and frozen at -20℃ for 12 hours, and finally freeze-dried for 24 hours to obtain micro gear-shaped shaped stretchable conductive radiation-proof fiber.

[0084] The process parameters for coaxial wet spinning are as follows:

[0085] The inner diameters of the inner and outer needles are 0.4 mm and 1.07 mm, respectively, and the length of the spinning guide tube is 27 cm;

[0086] The core injection rate was 0.1 ml / min, and the shell injection rate was 0.1 ml / min.

[0087] The coagulation bath used in coaxial wet spinning is a mixture of acetic acid, DMSO and water, with DMSO content of 15wt% and acetic acid content of 55wt%; the coagulation bath temperature is 25℃ and the coagulation bath soaking time is 4h.

[0088] like Figures 1-3 As shown, the finally obtained micro-gear-shaped stretchable conductive radiation-shielding fiber has a core-shell structure. The core layer has a circular cross-section, and the shell layer has a micro-gear-shaped cross-section. The average height of the gear protrusions is 30µm, and the average width is 20µm. Both the core layer substrate and the shell layer substrate are TPU. The surface of the core layer substrate has an interwoven micron-level pore structure, in which Bi2O3 and W2C are uniformly dispersed. MXene is uniformly dispersed in the shell layer substrate. The average diameter of the micro-gear-shaped stretchable conductive radiation-shielding fiber is 500µm, and the average thickness of the shell layer is 43.4µm. The elongation at break of the micro-gear-shaped stretchable conductive radiation-shielding fiber is 498%, and the electrical conductivity is 255S / m. Figure 4 As shown, the strain sensing range of the micro-gear-shaped stretchable conductive fiber is 0~297%, and the sensitivity range is 0~32483. After a single micro-gear-shaped stretchable conductive radiation shielding fiber undergoes 2000 stretching cycles at 0~50% strain, the resistance drift is 3.2%.

[0089] Micro-gear-shaped, stretchable, conductive, and radiation-shielding fibers are processed into a stretchable multifunctional fabric with a thickness of 1.65 cm using a weaving process. The stretchable multifunctional fabric has a three-layer structure with a warp density of 540 threads / 10 cm and a weft density of 300 threads / 10 cm. The X-ray shielding efficiency of the stretchable multifunctional fabric is 93.1%.

[0090] Comparative Example 1

[0091] A method for preparing conductive radiation-proof fiber is basically the same as in Example 1, except that the mass-volume ratio of TPU to DMSO in the shell spinning solution is changed from 0.85g:10ml to 1.5g:10ml.

[0092] The final conductive radiation shielding fiber shell has an average thickness of 100µm, a strain sensing range of 0~185%, and a sensitivity range of 0~9632. It is processed into a stretchable multifunctional fabric using a weaving process, and the stretchable multifunctional fabric has a shielding efficiency of 85.1% against X-rays.

[0093] Compared with Example 1, the strain sensing range and sensitivity of the conductive radiation shielding fiber in Comparative Example 1 decreased significantly, and the shielding efficiency of the fabric against X-rays decreased. This is because after increasing the mass fraction of TPU substrate in the shell spinning solution in Comparative Example 1, the difference in polymer concentration between the core and shell layers decreased, and the difference in shrinkage rate between the inside and outside decreased, resulting in insufficient formation of micro-gear-shaped structures. At the same time, a thicker circular shell layer was formed, which reduced the reflection loss of X-rays on the fiber surface. The conductivity of the outer layer decreased, and the relative slippage between MXenes generated during stretching decreased. The synergistic mechanism was missing, which combined to cause a significant decrease in the strain sensing range, sensitivity, and shielding efficiency of the fiber.

[0094] Comparative Example 2

[0095] A method for preparing conductive radiation-proof fiber is basically the same as in Example 1, except that: step (4) omits the process of preparing MXene and replaces MXene with an equal mass of single-walled carbon nanotubes (manufacturer: Jiangsu Xianfeng Nanomaterials Technology Co., Ltd., brand: XFS01), thus obtaining a single-walled carbon nanotube / DMSO dispersion.

[0096] The final conductive radiation shielding fiber shell has an average thickness of 40µm, a strain sensing range of 0~124%, and a sensitivity range of 0~12357. It is processed into a stretchable multifunctional fabric using a weaving process, and the stretchable multifunctional fabric has a shielding efficiency of 85.3% against X-rays.

[0097] Compared with Example 1, the strain sensing range and sensitivity of the conductive radiation shielding fiber in Comparative Example 2 were significantly reduced, and the shielding efficiency of the fabric against X-rays decreased. This is because in Comparative Example 2, MXene was replaced with single-walled carbon nanotubes of equal mass. The carbon nanotubes with a higher aspect ratio gradually align during spinning, hindering the increase in the difference between the inner and outer shrinkage rates, resulting in insufficient formation of micro-gear-shaped structures. At the same time, a thinner circular shell was formed, which reduced the reflection loss of X-rays on the fiber surface. Due to the addition of conductive filler carbon nanotubes, the outer layer has a high conductivity, but it is insufficient to support the large strain following the core layer during stretching, resulting in cracks. This leads to a significant decrease in the strain sensing range of the fiber, and the sensitivity and shielding efficiency against X-rays are lower than those in Example 1.

[0098] Comparative Example 3

[0099] A method for preparing a conductive radiation-proof fiber is basically the same as in Example 1, except that the shell injection rate in step (6) is 0.03 ml / min.

[0100] The final conductive radiation shielding fiber shell has an average thickness of 20µm, a strain sensing range of 0~207%, and a sensitivity range of 0~10549. It is processed into a stretchable multifunctional fabric using a weaving process, and the stretchable multifunctional fabric has a shielding efficiency of 83.6% for X-rays.

[0101] Compared with Example 1, Comparative Example 3 shows that the micro-gear-like structure on the surface of Comparative Example 3 disappears, the strain sensing range and sensitivity of the conductive radiation shielding fiber decrease significantly, and the shielding efficiency of the fabric against X-rays decreases. This is because Comparative Example 3 reduces the volume of spinning liquid in the shell layer that is in contact with the coagulation bath per unit time by reducing the shell layer injection speed, thus forming a thinner circular shell layer. Therefore, it is not easy to generate stacking that leads to micro-gear structures. The thinner smooth surface reduces the reflection loss of X-rays on the fiber surface. When stretched, the thinner shell layer is insufficient to support the large strain following the core layer, resulting in cracks. Consequently, the strain sensing range, sensitivity, and shielding efficiency of the fiber are lower than those of Example 1.

[0102] Comparative Example 4

[0103] A method for preparing a conductive radiation-proof fiber is basically the same as in Example 1, except that the shell injection rate in step (6) is 0.16 ml / min.

[0104] The final conductive radiation shielding fiber shell has an average thickness of 90µm, an overall fiber diameter of 400µm, and a circular cross-section. The strain sensing range of the conductive fiber is 0~143%, and the sensitivity range is 0~9600. It is processed into a stretchable multifunctional fabric using a weaving process. The stretchable multifunctional fabric has a shielding efficiency of 72.8% against X-rays.

[0105] Comparing Comparative Example 4 with Example 1, it can be found that the strain sensing range, sensitivity range, and X-ray shielding efficiency of Comparative Example 4 are significantly reduced. This is because the shell injection rate in Comparative Example 4 is relatively large, and the matching of the core and shell rates is poor. As a result, the formed fiber not only has a significantly increased shell thickness and a decreased core diameter, but also a gap is formed between the core and shell, leading to poor interfacial bonding, which in turn affects the strain sensing range and sensitivity range during stretching.

[0106] Comparative Example 5

[0107] A method for preparing conductive radiation-shielding fiber is basically the same as in Example 1, except that TPU is replaced with polyvinyl alcohol (PVA) in both the core substrate and the shell substrate, and the coagulation bath is a mixture of 75% acetone and 25 wt% deionized water.

[0108] The final obtained electro-radiation shielding fiber has a circular cross-section, a smooth surface, a shell thickness of 15µm, a strain sensing range of 0~40%, and a sensitivity range of 0~67. It is processed into a stretchable multifunctional fabric using a weaving process. The stretchable multifunctional fabric has a shielding efficiency of 82.1% against X-rays.

[0109] Compared with Example 1, the strain sensing range and sensitivity of the conductive radiation shielding fiber in Comparative Example 5 decreased significantly, and the shielding efficiency of the fabric against X-rays decreased. This is because the substrate of Comparative Example 5 is PVA, and the composition of the coagulation bath was also changed accordingly, resulting in a thinner circular shell. Since a strong hydrogen bond network is formed between PVA and MXene, only a small amount of MXene undergoes relative slippage during stretching. Furthermore, the circular structure is not conducive to enhancing the reflection loss of X-rays, and the synergistic mechanism is missing. As a result, the strain sensing range, sensitivity, and shielding efficiency of the fiber all decreased significantly.

[0110] Example 2

[0111] A method for preparing a micro-gear-shaped, stretchable, conductive, and radiation-shielding fiber, comprising the following specific steps:

[0112] (1) Preparation of raw materials:

[0113] TPU;

[0114] Radiation-shielding particle I: Tantalum pentoxide (Ta2O5), with an average particle size of 50 nm;

[0115] Radiation protection particles II: tungsten dicarbide (W2C), with an average particle size of 80 nm;

[0116] Organic solvent: N,N-dimethylformamide (DMF);

[0117] (2) Preparation of Ta2O5 / W2C / DMF dispersion:

[0118] Ta2O5 and W2C were added to DMF sequentially, and the mixture was ultrasonically sheared and dispersed to obtain a Ta2O5 / W2C / DMF dispersion.

[0119] The concentration of Ta2O5 in the Ta2O5 / W2C / DMF dispersion is 415 mg / ml, and the concentration of W2C is 190 mg / ml.

[0120] (3) Preparation of core spinning solution:

[0121] TPU was dissolved in a Ta2O5 / W2C / DMF dispersion and stirred at 150 rpm for 24 h. The mixture was then filtered, sonicated at 100 W for 30 min, and allowed to stand to defoam, resulting in a core spinning solution with a TPU to DMF mass-to-volume ratio of 2.2 g:10 ml.

[0122] (4) Preparation of MXene / DMF dispersion:

[0123] First, Ti3AlC2 powder was added to an HCl solution containing LiF and stirred at 36°C for 24 hours. Then, the reaction mixture was centrifuged and the lower precipitate was retained and repeatedly washed with water until the solution was neutral. Then, the upper liquid was removed by centrifugation using the solvent displacement method, and DMF was added and centrifuged to obtain MXene / DMF dispersion.

[0124] In this mixture, after adding Ti3AlC2 powder to the LiF-containing HCl solution, the concentration of Ti3AlC2 in the mixed solution was 0.05 g / ml, the concentration of LiF was 0.08 g / ml, and the concentration of MXene / DMF dispersion was 10 mg / ml.

[0125] (5) Preparation of shell spinning solution:

[0126] TPU was dissolved in MXene / DMF dispersion to obtain a shell spinning solution with a TPU to DMF mass-volume ratio of 0.7 g:10 ml;

[0127] (6) The core spinning solution and the shell spinning solution are coaxially wet-spun. After obtaining the nascent fiber through the coagulation bath, the nascent fiber is placed in deionized water for 12 hours, then taken out and frozen at -20℃ for 12 hours, and finally freeze-dried for 24 hours to obtain micro gear-shaped shaped stretchable conductive radiation-proof fiber.

[0128] The process parameters for coaxial wet spinning are as follows:

[0129] The inner diameters of the inner and outer needles are 0.4 mm and 1.07 mm, respectively, and the length of the spinning guide tube is 25 cm.

[0130] The core injection rate was 0.1 ml / min, and the shell injection rate was 0.13 ml / min.

[0131] The coagulation bath used in coaxial wet spinning is a mixture of acetic acid, DMF and water, with DMF content of 15wt% and acetic acid content of 55wt%; the coagulation bath temperature is 25℃ and the coagulation bath soaking time is 5h.

[0132] The final fabricated micro-gear-shaped stretchable conductive radiation-shielding fiber has a core-shell structure. The core layer has a circular cross-section, while the shell layer has a micro-gear-shaped cross-section. The average height of the gear protrusions is 23.2 µm, and the average width is 13.3 µm. Both the core and shell substrates are TPU. The surface of the core substrate has an interwoven micron-sized pore structure, in which Ta₂O₅ and W₂C are uniformly dispersed. The shell substrate contains uniformly dispersed MXene. The average diameter of the micro-gear-shaped stretchable conductive radiation-shielding fiber is 475 µm, and the average thickness of the shell is 37.3 µm. The elongation at break of the micro-gear-shaped stretchable conductive radiation-shielding fiber is 480%, and its conductivity is 145 S / m. The strain sensitivity range of the micro-gear-shaped stretchable conductive radiation-shielding fiber is 0–283%, and its sensitivity range is 0–27800. After 2000 tensile cycles at 0–50% strain, the resistance drift of a single micro-gear-shaped stretchable conductive radiation-shielding fiber is 2%.

[0133] Micro-gear-shaped, stretchable, conductive, and radiation-shielding fibers are processed into a stretchable multifunctional fabric with a thickness of 1.58 cm using a weaving process. The stretchable multifunctional fabric has a three-layer structure with a warp density of 560 threads / 10 cm and a weft density of 370 threads / 10 cm. The X-ray shielding efficiency of the stretchable multifunctional fabric is 95.3%.

[0134] Example 3

[0135] A method for preparing a micro-gear-shaped, stretchable, conductive, and radiation-shielding fiber, comprising the following specific steps:

[0136] (1) Preparation of raw materials:

[0137] TPU;

[0138] Radiation-resistant particle I: Bismuth oxide (Bi2O3), with an average particle size of 80 nm;

[0139] Radiation protection particles II: Barium sulfate (BaSO4), with an average particle size of 110 nm;

[0140] Organic solvent: N,N-dimethylacetamide (DMAC);

[0141] (2) Preparation of Bi2O3 / BaSO4 / DMAC dispersion:

[0142] Bi2O3 and BaSO4 were added to DMAC sequentially, and the mixture was ultrasonically sheared and dispersed to obtain a Bi2O3 / BaSO4 / DMAC dispersion.

[0143] The concentration of Bi2O3 in the Bi2O3 / BaSO4 / DMAC dispersion is 270 mg / ml, and the concentration of BaSO4 is 135 mg / ml.

[0144] (3) Preparation of core spinning solution:

[0145] TPU was dissolved in Bi2O3 / BaSO4 / DMAC dispersion and stirred at 150 rpm for 24 h. After that, the mixture was filtered, sonicated at 100 W for 30 min, and allowed to stand to defoam, to obtain a core spinning solution with a TPU to DMAC mass-volume ratio of 3 g:10 ml.

[0146] (4) Preparation of MXene / DMAC dispersion:

[0147] First, Ti3AlC2 powder was added to an HCl solution containing LiF and stirred at 36°C for 24 hours. Then, the reaction mixture was centrifuged and the lower precipitate was retained and repeatedly washed with water until the solution was neutral. Then, the upper liquid was removed by centrifugation using the solvent displacement method, and DMAC was added and centrifuged to obtain MXene / DMAC dispersion.

[0148] In this mixture, after adding Ti3AlC2 powder to the LiF-containing HCl solution, the concentration of Ti3AlC2 in the mixed solution was 0.05 g / ml, the concentration of LiF was 0.08 g / ml, and the concentration of MXene / DMAC dispersion was 18 mg / ml.

[0149] (5) Preparation of shell spinning solution:

[0150] TPU was dissolved in MXene / DMAC dispersion to obtain a shell spinning solution with a TPU to DMAC mass-volume ratio of 1g:10ml;

[0151] (6) The core spinning solution and the shell spinning solution are coaxially wet-spun. After obtaining the nascent fiber through the coagulation bath, the nascent fiber is placed in deionized water for 12 hours, then taken out and frozen at -20℃ for 12 hours, and finally freeze-dried for 24 hours to obtain micro gear-shaped shaped stretchable conductive radiation-proof fiber.

[0152] The process parameters for coaxial wet spinning are as follows:

[0153] The inner diameters of the inner and outer needles are 0.4 mm and 1.07 mm, respectively, and the length of the spinning guide tube is 30 cm.

[0154] The core injection rate was 0.2 ml / min, and the shell injection rate was 0.1 ml / min.

[0155] The coagulation bath used in coaxial wet spinning is a mixture of acetic acid, DMAC and water, with DMAC content of 20wt% and acetic acid content of 50wt%; the coagulation bath temperature is 27℃ and the coagulation bath soaking time is 3h.

[0156] The final fabricated micro-gear-shaped stretchable conductive radiation-shielding fiber has a core-shell structure. The core layer has a circular cross-section, while the shell layer has a micro-gear-shaped cross-section with an average gear protrusion height of 25.5µm and an average width of 10µm. Both the core and shell substrates are TPU. The core substrate surface has an interwoven micron-sized pore structure, in which Bi2O3 and BaSO4 are uniformly dispersed. The shell substrate contains uniformly dispersed MXene. The average diameter of the micro-gear-shaped stretchable conductive radiation-shielding fiber is 460µm, and the average thickness of the shell layer is 35µm. The fiber has a breaking elongation of 530% and an electrical conductivity of 198S / m. The strain sensitivity range of the fiber is 0–257%, and the sensitivity range is 0–27094. After 2000 tensile cycles at 0–50% strain, the resistance drift of a single micro-gear-shaped stretchable conductive radiation-shielding fiber is 5%.

[0157] Micro-gear-shaped, stretchable, conductive, and radiation-shielding fibers are processed into a stretchable multifunctional fabric with a thickness of 1.52 cm using a weaving process. The stretchable multifunctional fabric has a three-layer structure with a warp density of 480 threads / 10 cm and a weft density of 250 threads / 10 cm. The X-ray shielding efficiency of the stretchable multifunctional fabric is 91.2%.

[0158] Example 4

[0159] A method for preparing a micro-gear-shaped, stretchable, conductive, and radiation-shielding fiber, comprising the following specific steps:

[0160] (1) Preparation of raw materials:

[0161] TPU;

[0162] Radiation-shielding particle I: Tungsten dicarbide (W2C), with an average particle size of 90 nm;

[0163] Radiation protection particles II: Barium sulfate (BaSO4), with an average particle size of 120 nm;

[0164] Organic solvent: dimethyl sulfoxide (DMSO);

[0165] (2) Preparation of W2C / BaSO4 / DMSO dispersion:

[0166] W2C and BaSO4 were added to DMAC sequentially, and the mixture was ultrasonically sheared and dispersed to obtain a W2C / BaSO4 / DMSO dispersion.

[0167] The concentration of W2C in the W2C / BaSO4 / DMSO dispersion is 330 mg / ml, and the concentration of BaSO4 is 150 mg / ml.

[0168] (3) Preparation of core spinning solution:

[0169] TPU was dissolved in W2C / BaSO4 / DMSO dispersion and stirred at 150 rpm for 24 h. After stirring, the mixture was filtered, sonicated at 100 W for 30 min, and allowed to stand to defoam, resulting in a core spinning solution with a TPU to DMSO mass-to-volume ratio of 2.6 g:10 ml.

[0170] (4) Preparation of MXene / DMSO dispersion:

[0171] First, Ti3AlC2 powder was added to an HCl solution containing LiF and stirred at 36°C for 24 hours. Then, the reaction mixture was centrifuged and the lower precipitate was retained and repeatedly washed with water until the solution was neutral. Then, the upper liquid was removed by centrifugation using the solvent displacement method, and DMSO was added and centrifuged to obtain MXene / DMSO dispersion.

[0172] In this mixture, after adding Ti3AlC2 powder to the LiF-containing HCl solution, the concentration of Ti3AlC2 in the mixed solution was 0.04 g / ml, the concentration of LiF was 0.07 g / ml, and the concentration of MXene / DMSO dispersion was 15 mg / ml.

[0173] (5) Preparation of shell spinning solution:

[0174] TPU was dissolved in MXene / DMSO dispersion to obtain a shell spinning solution with a TPU to DMSO mass-volume ratio of 0.75 g: 10 ml;

[0175] (6) The core spinning solution and the shell spinning solution are coaxially wet-spun. After obtaining the nascent fiber through the coagulation bath, the nascent fiber is placed in deionized water for 12 hours, then taken out and frozen at -20℃ for 12 hours, and finally freeze-dried for 24 hours to obtain micro gear-shaped shaped stretchable conductive radiation-proof fiber.

[0176] The process parameters for coaxial wet spinning are as follows:

[0177] The inner diameters of the inner and outer needles are 0.4 mm and 1.07 mm, respectively, and the length of the spinning guide tube is 25 cm.

[0178] The core injection rate was 0.2 ml / min, and the shell injection rate was 0.08 ml / min.

[0179] The coagulation bath used in coaxial wet spinning is a mixture of acetic acid, DMSO and water, with DMSO content of 18wt% and acetic acid content of 52wt%; the coagulation bath temperature is 28℃ and the coagulation bath soaking time is 3h.

[0180] The final fabricated micro-gear-shaped stretchable conductive radiation-shielding fiber has a core-shell structure. The core layer has a circular cross-section, while the shell layer has a micro-gear-shaped cross-section with an average gear protrusion height of 20µm and an average width of 17.9µm. Both the core and shell substrates are TPU. The core substrate surface has an interwoven micron-sized pore structure, in which W2C and BaSO4 are uniformly dispersed, while MXene is uniformly dispersed in the shell substrate. The average diameter of the micro-gear-shaped stretchable conductive radiation-shielding fiber is 487µm, and the average thickness of the shell layer is 38.6µm. The breaking elongation of the micro-gear-shaped stretchable conductive radiation-shielding fiber is 521%, and its conductivity is 214S / m. The strain sensing range of the micro-gear-shaped stretchable conductive radiation-shielding fiber is 0~274%, and its sensitivity range is 0~28743. After 2000 tensile cycles at 0~50% strain, the resistance drift of a single micro-gear-shaped stretchable conductive radiation-shielding fiber is 4.5%.

[0181] The micro-gear-shaped, stretchable, conductive, and radiation-shielding fiber from Example 4 was processed into a stretchable multifunctional fabric with a thickness of 1.62 cm using a weaving process. The stretchable multifunctional fabric has a three-layer structure with a warp density of 500 threads / 10 cm and a weft density of 280 threads / 10 cm. The X-ray shielding efficiency of the stretchable multifunctional fabric is 92.3%.

[0182] Example 5

[0183] A method for preparing a micro-gear-shaped, stretchable, conductive, and radiation-shielding fiber, comprising the following specific steps:

[0184] (1) Preparation of raw materials:

[0185] TPU;

[0186] Radiation-resistant particle I: Bismuth oxide (Bi2O3), with an average particle size of 60 nm;

[0187] Radiation protection particles II: Tantalum pentoxide (Ta2O5), with an average particle size of 80 nm;

[0188] Organic solvent: dimethyl sulfoxide (DMF);

[0189] (2) Preparation of Bi2O3 / Ta2O5 / DMF dispersion:

[0190] Bi2O3 and Ta2O5 were added to DMF in sequence, and the mixture was dispersed by ultrasonic shearing to obtain a Bi2O3 / Ta2O5 / DMF dispersion.

[0191] The concentration of Bi2O3 in the Bi2O3 / Ta2O5 / DMF dispersion is 405 mg / ml, and the concentration of Ta2O5 is 195 mg / ml.

[0192] (3) Preparation of core spinning solution:

[0193] TPU was dissolved in a Bi2O3 / Ta2O5 / DMF dispersion and stirred at 150 rpm for 24 h. The mixture was then filtered, sonicated at 100 W for 30 min, and allowed to stand to defoam, resulting in a core spinning solution with a TPU to DMF mass-to-volume ratio of 2.5 g:10 ml.

[0194] (4) Preparation of MXene / DMF dispersion:

[0195] First, Ti3AlC2 powder was added to an HCl solution containing LiF and stirred at 36°C for 24 hours. Then, the reaction mixture was centrifuged and the lower precipitate was retained and repeatedly washed with water until the solution was neutral. Then, the upper liquid was removed by centrifugation using the solvent displacement method, and DMF was added and centrifuged to obtain MXene / DMF dispersion.

[0196] In this mixture, after adding Ti3AlC2 powder to the LiF-containing HCl solution, the concentration of Ti3AlC2 in the mixed solution was 0.06 g / ml, the concentration of LiF was 0.09 g / ml, and the concentration of MXene / DMF dispersion was 10 mg / ml.

[0197] (5) Preparation of shell spinning solution:

[0198] TPU was dissolved in MXene / DMF dispersion to obtain a shell spinning solution with a TPU to DMF mass-volume ratio of 0.5 g: 10 ml;

[0199] (6) The core spinning solution and the shell spinning solution are coaxially wet-spun. After obtaining the nascent fiber through the coagulation bath, the nascent fiber is placed in deionized water for 12 hours, then taken out and frozen at -20℃ for 12 hours, and finally freeze-dried for 24 hours to obtain micro gear-shaped shaped stretchable conductive radiation-proof fiber.

[0200] The process parameters for coaxial wet spinning are as follows:

[0201] The inner diameters of the inner and outer needles are 0.4 mm and 1.07 mm, respectively, and the length of the spinning guide tube is 30 cm.

[0202] The core injection rate was 0.3 ml / min, and the shell injection rate was 0.15 ml / min.

[0203] The coagulation bath used in coaxial wet spinning is a mixture of acetic acid, DMF and water, with DMF content of 15wt% and acetic acid content of 55wt%; the coagulation bath temperature is 29℃ and the coagulation bath soaking time is 4h.

[0204] The final fabricated micro-gear-shaped stretchable conductive radiation-shielding fiber has a core-shell structure. The core layer has a circular cross-section, while the shell layer has a micro-gear-shaped cross-section with an average gear protrusion height of 50µm and an average width of 55µm. Both the core and shell substrates are made of TPU. The core substrate surface has an interwoven micron-sized pore structure, in which Bi2O3 and Ta2O5 are uniformly dispersed. The shell substrate contains uniformly dispersed MXene. The average diameter of the micro-gear-shaped stretchable conductive radiation-shielding fiber is 496µm, and the average thickness of the shell layer is 40µm. The breaking elongation of the micro-gear-shaped stretchable conductive radiation-shielding fiber is 512%, and its conductivity is 280S / m. The strain sensing range of the micro-gear-shaped stretchable conductive radiation-shielding fiber is 0~269%, and its sensitivity range is 0~28904. After 2000 tensile cycles at 0~50% strain, the resistance drift of a single micro-gear-shaped stretchable conductive radiation-shielding fiber is 2.7%.

[0205] Micro-gear-shaped, stretchable, conductive, and radiation-shielding fibers were processed into a stretchable multifunctional fabric with a thickness of 1.63 cm using a weaving process. The stretchable multifunctional fabric has a three-layer structure with a warp density of 520 threads / 10 cm and a weft density of 370 threads / 10 cm. The X-ray shielding efficiency of the stretchable multifunctional fabric is 94.8%.

[0206] Example 6

[0207] A method for preparing a micro-gear-shaped, stretchable, conductive, and radiation-shielding fiber, comprising the following specific steps:

[0208] (1) Preparation of raw materials:

[0209] TPU;

[0210] Radiation-resistant particle I: Barium sulfate (BaSO4), with an average particle size of 60 nm;

[0211] Radiation-resistant particles II: Tantalum pentoxide (Ta2O5), with an average particle size of 100 nm;

[0212] Organic solvent: N,N-dimethylacetamide (DMAC);

[0213] (2) Preparation of BaSO4 / Ta2O5 / DMAC dispersion:

[0214] BaSO4 and Ta2O5 were added to DMAC sequentially, and the mixture was ultrasonically sheared and dispersed to obtain a BaSO4 / Ta2O5 / DMAC dispersion.

[0215] The concentration of BaSO4 in the BaSO4 / Ta2O5 / DMAC dispersion is 425 mg / ml, and the concentration of Ta2O5 is 175 mg / ml.

[0216] (3) Preparation of core spinning solution:

[0217] TPU was dissolved in BaSO4 / Ta2O5 / DMAC dispersion and stirred at 150 rpm for 24 h. After stirring, the mixture was filtered, sonicated at 100 W for 30 min, and allowed to stand to defoam, resulting in a core spinning solution with a TPU to DMAC mass-to-volume ratio of 2.5 g:10 ml.

[0218] (4) Preparation of MXene / DMAC dispersion:

[0219] First, Ti3AlC2 powder was added to an HCl solution containing LiF and stirred at 36°C for 24 hours. Then, the reaction mixture was centrifuged and the lower precipitate was retained and repeatedly washed with water until the solution was neutral. Then, the upper liquid was removed by centrifugation using the solvent displacement method, and DMAC was added and centrifuged to obtain MXene / DMAC dispersion.

[0220] In this mixture, after adding Ti3AlC2 powder to the LiF-containing HCl solution, the concentration of Ti3AlC2 in the mixed solution was 0.06 g / ml, the concentration of LiF was 0.09 g / ml, and the concentration of MXene / DMAC dispersion was 18 mg / ml.

[0221] (5) Preparation of shell spinning solution:

[0222] TPU was dissolved in MXene / DMAC dispersion to obtain a shell spinning solution with a TPU to DMAC mass-volume ratio of 1g:10ml;

[0223] (6) The core spinning solution and the shell spinning solution are coaxially wet-spun. After obtaining the nascent fiber through the coagulation bath, the nascent fiber is placed in deionized water for 12 hours, then taken out and frozen at -20℃ for 12 hours, and finally freeze-dried for 24 hours to obtain micro gear-shaped shaped stretchable conductive radiation-proof fiber.

[0224] The process parameters for coaxial wet spinning are as follows:

[0225] The inner diameters of the inner and outer needles are 0.4 mm and 1.07 mm, respectively, and the length of the spinning guide tube is 28 cm;

[0226] The core injection rate was 0.3 ml / min, and the shell injection rate was 0.09 ml / min.

[0227] The coagulation bath used in coaxial wet spinning is a mixture of acetic acid, DMAC and water, with DMAC content of 20wt% and acetic acid content of 50wt%; the coagulation bath temperature is 30℃ and the coagulation bath soaking time is 5h.

[0228] The final fabricated micro-gear-shaped, stretchable, conductive, and radiation-shielding fiber has a core-shell structure. The core layer has a circular cross-section, while the shell layer has a micro-gear-shaped cross-section. The average height of the gear protrusions is 32.2 µm, and the average width is 21.5 µm. Both the core and shell substrates are TPU. The surface of the core substrate has an interwoven micron-sized pore structure, in which BaSO4 and Ta2O5 are uniformly dispersed. MXene is uniformly dispersed in the shell substrate. The micro-gear-shaped, stretchable fiber... The conductive radiation shielding fiber has an average diameter of 498µm and an average shell thickness of 37.6µm; the micro-gear-shaped stretchable conductive radiation shielding fiber has a breaking elongation of 515% and an electrical conductivity of 175S / m; the strain sensing range of the micro-gear-shaped stretchable conductive fiber is 0~290%, and the sensitivity range is 0~31565; after a single micro-gear-shaped stretchable conductive radiation shielding fiber undergoes 2000 tensile cycles at 0~50% strain, the resistance drift is 2.9%.

[0229] Micro-gear-shaped, stretchable, conductive, and radiation-shielding fibers were processed into a stretchable multifunctional fabric with a thickness of 1.64 cm using a weaving process. The stretchable multifunctional fabric has a three-layer structure with a warp density of 540 threads / 10 cm and a weft density of 330 threads / 10 cm. The X-ray shielding efficiency of the stretchable multifunctional fabric is 93.9%.

Claims

1. A method for preparing a micro-gear-shaped, stretchable, conductive, and radiation-shielding fiber, characterized in that: Micro-gear-shaped, stretchable, conductive, and radiation-shielding fibers were prepared by coaxial wet spinning of the core layer spinning solution and the shell layer spinning solution. The core spinning solution is obtained by dissolving TPU in a dispersion of radiation-shielding particles I / radiation-shielding particles II / organic solvent, and the shell spinning solution is obtained by dissolving TPU in a dispersion of MXene / organic solvent. The mass-to-volume ratio of TPU to organic solvent in the core spinning solution is 2.2~3g:10ml, and the mass-to-volume ratio of TPU to organic solvent in the shell spinning solution is 0.5~1g:10ml. During coaxial wet spinning, the core injection rate is 0.1~0.3 ml / min, and the shell injection rate is 0.08~0.15 ml / min. The coagulation bath used in coaxial wet spinning is a mixture of organic solvent, acetic acid, and water, with the organic solvent content in the coagulation bath being 15-20 wt%. The core spinning solution, the shell spinning solution, and the organic solvent in the coagulation bath are all selected from one of DMSO, DMF, and DMAC.

2. The method for preparing a micro-gear-shaped, stretchable, conductive, and radiation-shielding fiber according to claim 1, characterized in that, The acetic acid content in the coagulation bath is 50-55 wt%.

3. The method for preparing a micro-gear-shaped, stretchable, conductive, and radiation-shielding fiber according to claim 2, characterized in that, During coaxial wet spinning, the inner diameters of the inner and outer needles are 0.4 mm and 1.07 mm, respectively, and the length of the spinning guide tube is 25~30 cm. The coagulation bath temperature is 25~30℃, and the coagulation bath soaking time is 3~5h; after coagulation and shaping, it is first washed with water and then freeze-dried.

4. The method for preparing a micro-gear-shaped, stretchable, conductive, and radiation-shielding fiber according to claim 1, characterized in that, The preparation process of the radiation protection particle I / radiation protection particle II / organic solvent dispersion is as follows: radiation protection particle I and radiation protection particle II are added to the organic solvent in sequence, and the dispersion is obtained by ultrasonic shearing.

5. The method for preparing a micro-gear-shaped, stretchable, conductive, and radiation-shielding fiber according to claim 4, characterized in that, Radiation-resistant particles I and radiation-resistant particles II are each independently selected from one of bismuth oxide, tungsten carbide, barium sulfate, and tantalum pentoxide; the average particle size of radiation-resistant particles I is 50~90nm, and the average particle size of radiation-resistant particles II is 80~120nm.

6. The method for preparing a micro-gear-shaped, stretchable, conductive, and radiation-shielding fiber according to claim 1, characterized in that, The preparation process of MXene / organic solvent dispersion is as follows: First, Ti3AlC2 powder is added to HCl solution containing LiF and stirred for 24 hours. Then, the reaction mixture is centrifuged and the lower precipitate is retained and repeatedly washed with water until the solution is neutral. Then, the upper liquid is removed by centrifugation using the solvent displacement method, and then organic solvent is added and centrifuged to obtain MXene / organic solvent dispersion.

7. The method for preparing a micro-gear-shaped, stretchable, conductive, and radiation-shielding fiber according to claim 6, characterized in that, After adding Ti3AlC2 powder to an HCl solution containing LiF, the concentration of Ti3AlC2 in the mixed solution is 0.04~0.06 g / ml, the concentration of LiF is 0.07~0.09 g / ml, and the concentration of MXene / organic solvent dispersion is 10~18 mg / ml.

8. A micro-gear-shaped, stretchable, conductive, and radiation-shielding fiber prepared by the method according to any one of claims 1 to 7, characterized in that: It has a core-shell structure, with a circular core cross-section and a micro-gear-shaped irregular structure in the shell cross-section. The average height of the gear protrusions is 20~50µm and the average width is 10~55µm. Both the core substrate and the shell substrate are TPU. The surface of the core substrate has an interwoven micron-sized pore structure, in which radiation-resistant particles I and radiation-resistant particles II are uniformly dispersed. MXene is uniformly dispersed in the shell substrate.

9. The micro-gear-shaped, irregularly shaped, stretchable, conductive, and radiation-shielding fiber according to claim 8, characterized in that, The average diameter of the micro-gear-shaped, stretchable, conductive, and radiation-shielding fiber is 460~500µm, and the average thickness of the shell is 35~40µm. The contents of radiation-shielding particles I and II in the core layer are 35.7~56.4wt% and 17.8~25.7wt%, respectively, while the contents of MXene in the shell layer are 12~18wt%.

10. A micro-gear-shaped, irregularly shaped, stretchable, conductive, and radiation-shielding fiber according to claim 9, characterized in that, The strain sensing range of the micro-gear-shaped stretchable conductive fiber is 0~297%, and the sensitivity range is 0~32483. After 2000 stretching cycles at 0~50% strain, the resistance drift of the micro-gear-shaped stretchable conductive radiation shielding fiber is 2~5%.

11. The application of the micro-gear-shaped, stretchable, conductive, and radiation-shielding fiber as described in any one of claims 8 to 10, characterized in that: It is processed into a stretchable, multifunctional fabric using machine weaving technology; The stretchable multifunctional fabric has a three-layer structure with a warp density of 480~560 threads / 10cm and a weft density of 250~370 threads / 10cm. The stretchable multifunctional fabric has an X-ray shielding efficiency of over 90%.

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