Micro-gear-shaped special-shaped stretchable conductive anti-radiation fiber as well as preparation and application thereof

Abstract

The invention belongs to the technical field of fiber materials, and relates to a micro-gear-shaped special-shaped stretchable conductive anti-radiation fiber and preparation and application thereof, a core layer spinning solution and a shell layer spinning solution are subjected to coaxial wet spinning to prepare the micro-gear-shaped special-shaped stretchable conductive anti-radiation fiber; the core layer spinning solution is obtained by dissolving TPU in anti-radiation particles I / anti-radiation particles II / organic solvent dispersion, and the shell layer spinning solution is obtained by dissolving TPU in MXene / organic solvent dispersion; the mass volume ratio of the TPU to the organic solvent in the core layer spinning solution is (2.2-3g): 10ml, and the mass volume ratio of the TPU to the organic solvent in the shell layer spinning solution is (0.5-1g): 10ml; the anti-radiation fiber is of a core-shell structure, the cross section of a core layer is circular, the cross section of a shell layer is of a micro-gear-shaped special-shaped structure, and the average height of gear protrusions is 20-50 m; when being applied, the fabric is processed into a stretchable multifunctional fabric by adopting a weaving process. According to the method, a coaxial wet spinning process is adopted to prepare the product in one step; the product has high sensitivity and a wide sensing range; the application range is wide.

Description

Technical Field

[0001] The present invention belongs to the technical field of fiber materials and relates to a micro-gear-shaped special-shaped stretchable conductive radiation-proof fiber and its preparation and application. Background Art

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

[0003] Studies have shown that currently in clinical medicine, 80% of interventional procedures for disease diagnosis and treatment using minimally invasive instruments and real-time guidance from medical imaging require continuous X-ray exposure. Workers typically wear 8-10kg lead protective clothing and maintain a forward-leaning posture while performing surgery. This not only places a heavy burden on the lumbar spine, but also significantly affects the worker's comfort and joint flexibility. This is because existing protective clothing is made of metal lead wire as yarn through weaving, knitting and other manufacturing methods. It is highly rigid and has a bending degree of less than 30%. In addition, lead materials are highly toxic and are not conducive to contact with the skin, and the waste causes significant environmental pollution.

[0004] To address these deficiencies, lead-free protective clothing has been developed. For example, patent application CN119877294A discloses a flexible, lead-free X-ray protective coating fabric and its preparation method. Bismuth oxide, transparent liquid silicone rubber A, transparent liquid silicone rubber B, and ethyl acetate are mixed and then applied multiple times to a polyester fabric. After curing and setting, the resulting lead-free X-ray protective fabric, suitable for examinees, is obtained. This protective coating fabric is non-toxic, lightweight, and flexible, but its single radiation-shielding component results in a low X-ray shielding efficiency of only 29.73%. Furthermore, post-processing reduces the comfort and breathability of the shielding fabric, making it difficult to meet the required protective and comfort requirements during X-ray exposure. When stretched to follow the posture of the human body, the fibers, due to the Poisson effect, create pores that allow X-rays to pass through, further reducing the protective effect.

[0005] In addition, existing radiation-proof fibers also use prestressing to form surface wrinkles or microcracks, but their structure is irregular corrugated and has low sensitivity under tension. For example, the document (Sensor Actuat A-phys, 2023, 360, 114510) achieves a sensitivity factor (GF) of 136100 by designing a double-layer structure, but only within a small strain range of 2%. Patent CN119468899A achieves a strain sensing range of 320% by designing a three-layer membrane structure consisting of a stretchable elastic substrate, a strain-sensitive layer, and a stretchable elastic package, but the maximum sensitivity is only around 650. In this regard, it is still challenging to develop fibers that simultaneously achieve a high sensing range and high sensitivity.

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

[0007] The purpose of the present invention is to solve the problems existing in the prior art and provide a micro-gear-shaped special-shaped stretchable conductive radiation-proof fiber and its preparation and application.

[0008] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0009] A method for preparing a micro-gear-shaped, special-shaped, stretchable, conductive, and radiation-proof fiber comprises coaxially wet-spinning a core layer spinning solution and a shell layer spinning solution to produce the micro-gear-shaped, special-shaped, stretchable, conductive, and radiation-proof fiber;

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

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

[0012] During coaxial wet spinning, the shell injection rate is 0.08~0.15ml / min. If the shell injection rate is less than 0.08ml / min, the shell thickness will be too small and the micro-gear structure will tend to disappear. If the shell injection rate is greater than 0.15ml / min, it will also be detrimental to the formation of the micro-gear structure.

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

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

[0015] As the preferred technical solution:

[0016] In the method for preparing the micro-gear-shaped special-shaped stretchable conductive radiation-proof fiber as described above, the content of acetic acid in the coagulation bath is 50-55 wt %.

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

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

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

[0020] The well-known high-power ultrasonic-shear dispersion method is used here, and the operation treatment is carried out at 500W power and 20 minutes in a cell crusher. These are process parameters that have been gradually confirmed in actual operation. Low-power dispersion makes the sedimentation rate of high-density radiation-proof compound particles in organic solvents greater than 40%. At the same time, the treatment time of less than 15 minutes will also cause uneven dispersion. The use of a moderate 500W and 20 minutes is the preferred parameter window for the experiment to better balance stability and purity.

[0021] As described above, the method for preparing a micro-gear-shaped, special-shaped, stretchable conductive radiation-proof fiber, wherein the radiation-proof particles I and the radiation-proof 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 the radiation-proof particles I is 50~90nm, and the average particle size of the radiation-proof particles II is 80~120nm.

[0022] As described above, a method for preparing a micro-gear-shaped, special-shaped, stretchable conductive radiation-proof fiber, the preparation process of the MXene / organic solvent dispersion is as follows: first, Ti3AlC2 powder is added to a HCl solution containing LiF and stirred for reaction for 24 hours, then the reaction mixture is centrifuged, the lower layer of sediment is retained and repeatedly washed with water until the solution is neutral, and then a solvent replacement method is used to remove the upper layer of liquid by centrifugation, and then an organic solvent is added and centrifuged to obtain a MXene / organic solvent dispersion.

[0023] As described above, a method for preparing a micro-gear-shaped, special-shaped, stretchable conductive radiation-proof fiber is described. After Ti3AlC2 powder is added to a LiF-containing HCl solution (HCl solution concentration is 9M), the Ti3AlC2 concentration in the mixed solution is 0.04~0.06g / ml, and the LiF concentration is 0.07~0.09g / ml; the concentration of the MXene / organic solvent dispersion is 10~18mg / ml.

[0024] The present invention also provides a micro-gear-shaped, special-shaped, stretchable conductive radiation-proof fiber prepared by the method described in any one of the above, having a core-shell structure, wherein the core layer has a circular cross-section and the shell layer has a micro-gear-shaped special-shaped structure, and the average height of the gear protrusions is 20-50 μm and the average width is 10-55 μm;

[0025] Both the core layer substrate and the shell layer substrate are TPU. The surface of the core layer substrate has an interlaced micron-scale pore structure, in which radiation-proof particles I and radiation-proof particles II are evenly dispersed, and MXene is evenly dispersed in the shell layer substrate.

[0026] As the preferred technical solution:

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

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

[0029] As described above, the micro-gear-shaped shaped stretchable conductive radiation-proof fiber has a strain sensing range of 0~297% and a sensitivity range of 0~32483; after 2000 stretching cycles of the micro-gear-shaped shaped stretchable conductive radiation-proof fiber under a strain of 0~50%, the resistance drift is 2~5%, proving that the conductive shaped shell has excellent stability within this strain range; the micro-gear-shaped shaped stretchable conductive radiation-proof fiber has an elongation at break of 480~530% and a conductivity of 145~280S / m.

[0030] The present invention also provides an application of a micro-gear-shaped special-shaped stretchable conductive radiation-proof fiber as described in any one of the above items, 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 shielding efficiency of stretchable multifunctional fabric against X-rays is over 90%.

[0033] Principle of the invention:

[0034] The present invention uses coaxial wet spinning technology to produce highly conductive stretchable shaped composite fibers in one step, and can achieve large-scale batch production. The stretchable shaped composite fibers prepared by the present invention cleverly utilize the heterogeneous shrinkage of two-dimensional MXene and TPU during the wet spinning process to successfully construct a dense and continuous conductive network on the surface of the radiation shielding particles I / radiation shielding particles II / TPU core fiber (see Figure 2 ), well-formed, with no obvious gaps between the core and shell layers, overcoming the problem that existing doped conductive composite fibers are difficult to balance high conductivity and mechanical properties, and forming an interlaced micron-scale pore structure inside the fiber (see Figure 3 ), forming a shaped structure with multi-axial protrusions on the surface, thereby producing an X-ray-shielding shaped composite fiber with high elongation at break, good flexibility, and high conductivity. The intersection of the protrusions and the circular arc in the cross-section of this conductive shaped fiber has a larger MXene contact area, and the conductive network structure is denser. During stretching, more conductive components MXene slip between each other, resulting in higher sensitivity. The high concentration of polymer and radiation-shielding particles in the fiber core effectively safeguards the fiber's mechanical properties, maintaining a good conductive path under high strain. As a result, the composite fiber has good conductivity, stability, flexibility, and efficient X-ray protection.

[0035] The micro-gear-shaped, stretchable, conductive, and radiation-protective fiber fabricated in this invention is formed by the following mechanism: When the spinning solution enters the coagulation bath, the shell spinning solution comes into direct contact with the coagulation bath, resulting in solvent exchange between the two. The high-concentration organic solvent in the spinning solution (relative to the coagulation bath) rapidly permeates the coagulation bath, while the non-solvent in the coagulation bath gradually seeps into the spinning solution, causing TPU phase separation and the initial formation of the fiber shell. Solvent removal causes the polymer chains to lose their solvation layer, enhancing interchain forces and generating shrinkage stress. However, due to the difference in polymer concentration, the low-concentration shell (relative to the core) generates greater shrinkage stress. After the initial formation of the fiber shell, the high-modulus MXene (≈330 GPa) is sandwiched between the rapidly shrinking thickness direction and the constrained in-plane direction. Under the pressure of the sudden increase in interchain forces after solvent removal, the stacking arrangement causes wrinkling, which "relieving pressure," forming the precursor to the subsequent micro-gear protrusions. Under the stacking of MXene sheets, the space allowed for liquid to pass through is reduced, 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 core layer's high-concentration TPU / radiation-proof particles I / radiation-proof particles II / organic solvent spinning solution itself make the solvent expand slowly. With the increase of MXene content, the longitudinal solubility rate further decreases, resulting in a huge difference in the core-shell shrinkage rate. The shell layer continuously tightens and compresses toward the core layer during the molding process, and stacks to adapt to the slow shrinkage rate of the core layer, forming a micro-gear-shaped special-shaped structure in the cross section; after the initial phase separation is completed, the water molecules and acetic acid in the coagulation bath can only penetrate the micropores on the surface of the primary fiber shell layer for solvent replacement, and the phase separation rate of the core layer TPU is slowed down, and a dense micron-level pore structure of the core layer is gradually formed inward.

[0036] Beneficial effects:

[0037] (1) The present invention provides a method for preparing a micro-gear-shaped special-shaped stretchable conductive radiation-proof fiber, which is prepared by coaxial wet spinning. The micro-gear-shaped special-shaped core-shell fiber is used as the substrate. Under the synergistic effect of appropriate spinning process parameters, core-shell substrate ratio, and conductive filler ratio, high-performance micro-gear-shaped special-shaped stretchable conductive radiation-proof fiber is prepared in one step. The micro-gear structure not only structurally compensates for the reflection loss of the enhanced X-ray, but also synergistically improves the high sensitivity and tensile stability of the fiber material during stretching. The method has the characteristics of simple preparation method, controllable structure, and mass production.

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

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

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

[0041] (5) The micro-gear-shaped special-shaped stretchable conductive radiation-proof fiber of the present invention forms a dense pore structure inside the fiber by coaxial wet spinning. Compared with uniaxial spinning, loose porous fibers can be obtained when stretched multiple times, with a lower resistance change rate and better dynamic stability.

[0042] (6) The present invention relates to a micro-gear-shaped, special-shaped, stretchable conductive radiation-proof fiber. The periodic surface structure of the micro-gear protrusions increases the reflection path of X-rays between the shell MXene layers. 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 rich groups and active sites on the MXene surface are more fully exposed, and the reaction activity is enhanced compared to smooth fibers, which can be further post-processed to achieve functionalization.

[0043] (7) The micro-gear-shaped special-shaped 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, thermal therapy and health care products, one-way water guides, sensors and capacitors. BRIEF DESCRIPTION OF THE DRAWINGS

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

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

[0046] Figure 3 This is an enlarged FE-SEM image of the cross section of the fiber of Example 1 of the present invention.

[0047] Figure 4The fiber sensing range and sensitivity GF obtained in Example 1 of the present invention are as follows; wherein, R 2 It is a statistical indicator of goodness of fit, reflecting the degree of linear correlation between resistance change and strain. The closer the value is to 1, the closer it is to a linear relationship. DETAILED DESCRIPTION

[0048] Below in conjunction with specific embodiment, further set forth the present invention.Should be understood that these embodiments are only used to illustrate the present invention and are not used in limiting the scope of the present invention.In addition, should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall equally within the scope limited by the appended claims of the application.

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

[0050] X-ray shielding efficiency: The test is carried out in accordance with the provisions of GBZ / T 147-2002. The X-ray shielding efficiency is the percentage of the difference in X-ray dose between the sample without and the sample added to the initial dose. 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 according to the following formula:

[0051] η=(n0-n d ) / (n0-n b )×100%;

[0052] Where: η represents the shielding rate of X-rays (%), n0 is the dose rate at the initial incidence, n d is the dose rate after passing through the sample, n b is the background rate.

[0053] Strain sensing range and sensitivity GF: The strain sensing range is the range in which the sample device can monitor the resistance change during the stretching process, and the sensitivity is the percentage of the resistance change of the sample during the stretching process to the length change. The common measurement method is to clamp copper foil at both ends of the sample (referring to a single micro-gear-shaped special-shaped stretchable conductive radiation-proof fiber) and fix it on the stretching device, and connect the ohmmeter of the multimeter to form a path. As the stretching distance gradually increases, the resistance gradually increases accordingly. When the resistance reading is infinite, the test stops. The stretching distance in this process is the strain sensing range. Accordingly, the sensitivity under strain at a certain moment in the stretching process can be calculated according to the following formula:

[0054] GF=ΔR / (R0*ε);

[0055] ε=ΔL / L0;

[0056] Where: 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 the stretched length at a certain section and the initial length; L0 is the initial length.

[0057] Elongation at break: In accordance with GB / T 14344-2022, tensile strain is applied to fiber specimens using a universal tensile testing machine with a gauge length of 10 mm and a displacement rate of 10 mm / min. As the stretching distance gradually increases, the fiber contracts perpendicular to its length due to the Poisson effect until the fiber specimen breaks, at which point the test is terminated. The strain value corresponding to the breaking point of the stress-strain curve is the elongation at break.

[0058] Conductivity: Based on the standard T / SZJL 8-2024, a single fiber is tested using the four-point probe method. The fiber sample is fixed to an insulating substrate, a constant DC current I is applied along the fiber axis, and the voltage drop ΔV is measured. Calculate using the following formula:

[0059] σ = L / (R • A);

[0060] R=ΔV / I;

[0061] A=π(D 2 -d 2 ) / 4;

[0062] Where: L is the probe distance, 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 substances of the present invention are as follows:

[0064] TPU: The manufacturer is BASF, and the brand is 1170A.

[0065] PVA: The manufacturer is Shanghai Aladdin Biochemical Technology Co., Ltd., and the brand number is 224.

[0066] Example 1

[0067] A method for preparing micro-gear-shaped, special-shaped, stretchable, conductive, radiation-proof fiber, comprising the following steps:

[0068] (1) Preparation of raw materials:

[0069] TPU;

[0070] Radiation protection particles I: bismuth oxide (Bi2O3), average particle size 60nm;

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

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

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

[0074] Bi2O3 and W2C were sequentially added to DMSO, and Bi2O3 / W2C / DMSO dispersion was obtained by ultrasonic shear dispersion.

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

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

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

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

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

[0080] Among them, after adding Ti3AlC2 powder to the HCl solution containing LiF, the concentration of Ti3AlC2 in the mixed solution was 0.05g / ml and the concentration of LiF was 0.08g / ml; the concentration of MXene / DMSO dispersion was 18mg / ml;

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

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

[0083] (6) The core layer spinning solution and the shell layer spinning solution were coaxially wet-spun to obtain nascent fibers after a coagulation bath. The nascent fibers were then immersed in deionized water for 12 hours, then taken out and frozen at -20 ° C for 12 hours, and finally freeze-dried for 24 hours to obtain micro-gear-shaped, special-shaped, stretchable, conductive, and radiation-proof fibers.

[0084] The process parameters of 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 spinning tube length is 27 cm;

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

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

[0088] like Figures 1-3 As shown in the figure, the final micro-gear-shaped stretchable conductive radiation-proof fiber has a core-shell structure, the core layer cross-section is circular, the shell layer cross-section is a micro-gear-shaped structure, the average height of the gear protrusion is 30µm, and the average width is 20µm; the core layer substrate and the shell layer substrate are both TPU, and the surface of the core layer substrate has an interlaced micron-scale pore structure, Bi2O3 and W2C are uniformly dispersed in the micron-scale pore structure, and MXene is uniformly dispersed in the shell layer substrate; the average diameter of the micro-gear-shaped stretchable conductive radiation-proof fiber is 500µm, and the average thickness of the shell layer is 43.4μm; the micro-gear-shaped stretchable conductive radiation-proof fiber has an elongation at break of 498% and an electrical conductivity of 255S / m; as shown in the figure Figure 4 As shown in the figure, the strain sensing range of the micro-gear-shaped special-shaped stretchable conductive fiber is 0~297%, and the sensitivity range is 0~32483; after 2000 stretching cycles of a single micro-gear-shaped special-shaped stretchable conductive radiation-proof fiber under 0~50% strain, the resistance drift is 3.2%.

[0089] The micro-gear-shaped special-shaped stretchable conductive radiation-proof fiber is 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 stretchable multifunctional fabric has a shielding efficiency of 93.1% against X-rays.

[0090] Comparative Example 1

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

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

[0093] Comparing Comparative Example 1 with Example 1, the strain sensing range and sensitivity of the conductive radiation-proof fiber of Comparative Example 1 are significantly reduced, and the shielding efficiency of the fabric against X-rays is reduced. This is because after the mass fraction of the TPU substrate in the shell spinning solution is increased in Comparative Example 1, the difference in core-shell polymer concentration is reduced, and the difference in inner and outer shrinkage rates is reduced, resulting in insufficient formation of a micro-gear special-shaped structure. At the same time, a thicker circular shell is formed, which reduces the reflection loss of X-rays on the fiber surface, reduces the electrical conductivity of the outer layer, reduces the relative slip between the MXenes generated during stretching, and lacks a synergistic mechanism, which leads to a significant decrease in the strain sensing range, sensitivity, and X-ray shielding efficiency of the fiber.

[0094] Comparative Example 2

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

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

[0097] Comparing Comparative Example 2 with Example 1, the strain sensing range and sensitivity of the conductive radiation-proof fiber of Comparative Example 2 are significantly reduced, and the shielding efficiency of the fabric against X-rays is reduced. This is because MXene is replaced with single-walled carbon nanotubes of equal mass in Comparative Example 2. The carbon nanotubes with a higher aspect ratio are gradually oriented during the spinning process, which hinders the increase in the difference in shrinkage rate between the inside and outside, resulting in insufficient formation of a micro-gear special-shaped structure. At the same time, a thinner circular shell is formed, which reduces the reflection loss of X-rays on the fiber surface. Due to the addition of conductive filler carbon nanotubes, the outer layer has a higher conductivity, but when stretched, the outer layer is not enough to support the larger strain following the core layer, resulting in cracks, resulting in a significant decrease in the strain sensing range of the fiber, and a decrease in sensitivity and X-ray shielding efficiency compared to Example 1.

[0098] Comparative Example 3

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

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

[0101] Comparing Comparative Example 3 with Example 1, the micro-gear-like structure on the surface of Comparative Example 3 disappears, the strain sensing range and sensitivity of the conductive radiation-proof fiber are significantly reduced, and the shielding efficiency of the fabric against X-rays is reduced. This is because Comparative Example 3 reduces the volume of shell spinning solution in contact with the coagulation bath per unit time by reducing the shell injection speed, thereby forming a thinner circular shell layer, so it is not easy to produce stacking and lead to micro-gear structure. The thinner smooth surface reduces the reflection loss of X-rays on the fiber surface. When stretched, the thinner shell layer is not sufficient to support the larger strain following the core layer, resulting in cracks, resulting in the strain sensing range, sensitivity and X-ray shielding efficiency of the fiber being reduced compared with Example 1.

[0102] Comparative Example 4

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

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

[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 greatly reduced. This is because the shell injection rate in Comparative Example 4 is relatively large, and the rate matching between the core layer and the shell layer is poor. The formed fiber not only has a greatly increased shell thickness and a decreased core layer diameter, but also forms a gap between the core layer and the shell layer, resulting in poor interface bonding, which in turn affects the strain sensing range and sensitivity range during stretching.

[0106] Comparative Example 5

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

[0108] The final electric radiation-proof 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 an X-ray shielding efficiency of 82.1%.

[0109] Comparing Comparative Example 5 with Example 1, the strain sensing range and sensitivity of the conductive radiation-proof fiber of Comparative Example 5 are significantly reduced, and the shielding efficiency of the fabric against X-rays is reduced. This is because the substrate of Comparative Example 5 is PVA, and the composition of the coagulation bath is also changed accordingly, thereby forming a thinner circular shell layer. Due to the strong hydrogen bond network formed between PVA and MXene, only a small amount of MXene produces relative slip during stretching, and the circular structure is not conducive to enhancing the reflection loss of X-rays, and the synergistic mechanism is missing, which leads to a significant decrease in the strain sensing range, sensitivity, and X-ray shielding efficiency of the fiber.

[0110] Example 2

[0111] A method for preparing micro-gear-shaped, special-shaped, stretchable, conductive, radiation-proof fiber, comprising the following steps:

[0112] (1) Preparation of raw materials:

[0113] TPU;

[0114] Radiation protection particles I: Tantalum pentoxide (Ta2O5), average particle size 50nm;

[0115] Radiation protection particles II: tungsten carbide (W2C), average particle size 80nm;

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

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

[0118] Ta2O5 and W2C were sequentially added to DMF, and Ta2O5 / W2C / DMF dispersion was obtained by ultrasonic shear 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 layer spinning solution:

[0121] TPU was dissolved in Ta2O5 / W2C / DMF dispersion, stirred at 150 rpm for 24 h, filtered, ultrasonicated at 100 W for 30 min, and allowed to stand for defoaming to obtain a core spinning solution with a mass volume ratio of TPU to DMF of 2.2 g:10 ml;

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

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

[0124] Among them, after adding Ti3AlC2 powder to the HCl solution containing LiF, the concentration of Ti3AlC2 in the mixed solution is 0.05g / ml, the concentration of LiF is 0.08g / ml; the concentration of MXene / DMF dispersion is 10mg / 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 layer spinning solution and the shell layer spinning solution were coaxially wet-spun to obtain nascent fibers after a coagulation bath. The nascent fibers were then immersed in deionized water for 12 hours, then taken out and frozen at -20 ° C for 12 hours, and finally freeze-dried for 24 hours to obtain micro-gear-shaped, special-shaped, stretchable, conductive, and radiation-proof fibers.

[0128] The process parameters of 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 spinning tube length is 25 cm;

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

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

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

[0133] The micro-gear-shaped special-shaped stretchable conductive radiation-proof fiber is 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 stretchable multifunctional fabric has a shielding efficiency of 95.3% against X-rays.

[0134] Example 3

[0135] A method for preparing micro-gear-shaped, special-shaped, stretchable, conductive, radiation-proof fiber, comprising the following steps:

[0136] (1) Preparation of raw materials:

[0137] TPU;

[0138] Radiation protection particles I: bismuth oxide (Bi2O3), average particle size 80nm;

[0139] Radiation protection particles II: barium sulfate (BaSO4), average particle size 110nm;

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

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

[0142] Bi2O3 and BaSO4 were sequentially added to DMAC, and Bi2O3 / BaSO4 / DMAC dispersion was obtained by ultrasonic shear dispersion.

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

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

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

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

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

[0148] Among them, after adding Ti3AlC2 powder to the HCl solution containing LiF, the concentration of Ti3AlC2 in the mixed solution was 0.05g / ml and the concentration of LiF was 0.08g / ml; the concentration of MXene / DMAC dispersion was 18mg / ml;

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

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

[0151] (6) The core layer spinning solution and the shell layer spinning solution were coaxially wet-spun to obtain nascent fibers after a coagulation bath. The nascent fibers were then immersed in deionized water for 12 hours, then taken out and frozen at -20 ° C for 12 hours, and finally freeze-dried for 24 hours to obtain micro-gear-shaped, special-shaped, stretchable, conductive, and radiation-proof fibers.

[0152] The process parameters of 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 spinning tube length is 30 cm;

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

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

[0156] The final micro-gear-shaped stretchable conductive radiation-proof fiber has a core-shell structure, with a circular core cross-section and a micro-gear-shaped shell cross-section. The average height of the gear protrusions is 25.5µm and the average width is 10µm. Both the core and shell substrates are TPU. The surface of the core substrate has an interlaced and interconnected micron-scale pore structure, in which Bi2O3 and BaSO4 are uniformly dispersed, and the shell substrate is uniformly dispersed with MXene. The average diameter of the micro-gear-shaped stretchable conductive radiation-proof fiber is 460µm, and the average thickness of the shell is 35μm. The elongation at break of the micro-gear-shaped stretchable conductive radiation-proof fiber is 530%, and the conductivity is 198S / m. The strain sensing range of the micro-gear-shaped stretchable conductive fiber is 0-257%, and the sensitivity range is 0-27094. After 2000 stretching cycles of a single micro-gear-shaped stretchable conductive radiation-proof fiber under a strain of 0-50%, the resistance drift is 5%.

[0157] The micro-gear-shaped special-shaped stretchable conductive radiation-proof fiber is 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 stretchable multifunctional fabric has a shielding efficiency of 91.2% against X-rays.

[0158] Example 4

[0159] A method for preparing micro-gear-shaped, special-shaped, stretchable, conductive, radiation-proof fiber, comprising the following steps:

[0160] (1) Preparation of raw materials:

[0161] TPU;

[0162] Radiation protection particles I: tungsten carbide (W2C), average particle size 90nm;

[0163] Radiation protection particles II: barium sulfate (BaSO4), average particle size 120nm;

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

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

[0166] W2C and BaSO4 were sequentially added to DMAC, and W2C / BaSO4 / DMSO dispersion was obtained by ultrasonic shear dispersion.

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

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

[0169] TPU was dissolved in W2C / BaSO4 / DMSO dispersion, stirred at 150 rpm for 24 h, filtered, ultrasonicated at 100 W for 30 min, and allowed to stand for defoaming to obtain a core spinning solution with a mass volume ratio of TPU to DMSO of 2.6 g:10 ml;

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

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

[0172] Among them, after adding Ti3AlC2 powder to the HCl solution containing LiF, the concentration of Ti3AlC2 in the mixed solution was 0.04g / ml and the concentration of LiF was 0.07g / ml; the concentration of MXene / DMSO dispersion was 15mg / ml;

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

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

[0175] (6) The core layer spinning solution and the shell layer spinning solution were coaxially wet-spun to obtain nascent fibers after a coagulation bath. The nascent fibers were then immersed in deionized water for 12 hours, then taken out and frozen at -20 ° C for 12 hours, and finally freeze-dried for 24 hours to obtain micro-gear-shaped, special-shaped, stretchable, conductive, and radiation-proof fibers.

[0176] The process parameters of 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 spinning tube length is 25 cm;

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

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

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

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

[0182] Example 5

[0183] A method for preparing micro-gear-shaped, special-shaped, stretchable, conductive, radiation-proof fiber, comprising the following steps:

[0184] (1) Preparation of raw materials:

[0185] TPU;

[0186] Radiation protection particles I: bismuth oxide (Bi2O3), average particle size 60nm;

[0187] Radiation protection particles II: tantalum pentoxide (Ta2O5), average particle size 80nm;

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

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

[0190] Bi2O3 and Ta2O5 were sequentially added to DMF, and Bi2O3 / Ta2O5 / DMF dispersion was obtained by ultrasonic shear 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 layer spinning solution:

[0193] TPU was dissolved in Bi2O3 / Ta2O5 / DMF dispersion, stirred at 150 rpm for 24 h, filtered, ultrasonicated at 100 W for 30 min, and allowed to stand for defoaming to obtain a core spinning solution with a mass volume ratio of TPU to DMF of 2.5 g:10 ml;

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

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

[0196] Among them, after adding Ti3AlC2 powder to the HCl solution containing LiF, the concentration of Ti3AlC2 in the mixed solution was 0.06g / ml and the concentration of LiF was 0.09g / ml; the concentration of MXene / DMF dispersion was 10mg / ml;

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

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

[0199] (6) The core layer spinning solution and the shell layer spinning solution were coaxially wet-spun to obtain nascent fibers after a coagulation bath. The nascent fibers were then immersed in deionized water for 12 hours, then taken out and frozen at -20 ° C for 12 hours, and finally freeze-dried for 24 hours to obtain micro-gear-shaped, special-shaped, stretchable, conductive, and radiation-proof fibers.

[0200] The process parameters of 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 spinning tube length is 30 cm;

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

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

[0204] The final micro-gear-shaped stretchable conductive radiation-proof fiber has a core-shell structure, with a circular core cross-section and a micro-gear-shaped shell cross-section. The average height of the gear protrusions is 50µm and the average width is 55µm. Both the core and shell substrates are TPU. The surface of the core substrate has an interlaced and interconnected micron-scale pore structure, in which Bi2O3 and Ta2O5 are uniformly dispersed, while the shell substrate is uniformly dispersed with MXene. The average diameter of the micro-gear-shaped stretchable conductive radiation-proof fiber is 496µm, and the average thickness of the shell is 40μm. The elongation at break of the micro-gear-shaped stretchable conductive radiation-proof fiber is 512%, and the conductivity is 280S / m. The strain sensing range of the micro-gear-shaped stretchable conductive fiber is 0-269%, and the sensitivity range is 0-28904. After 2000 stretching cycles of a single micro-gear-shaped stretchable conductive radiation-proof fiber under a strain of 0-50%, the resistance drift is 2.7%.

[0205] The micro-gear-shaped special-shaped stretchable conductive radiation-proof fiber is 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 stretchable multifunctional fabric has a shielding efficiency of 94.8% against X-rays.

[0206] Example 6

[0207] A method for preparing micro-gear-shaped, special-shaped, stretchable, conductive, radiation-proof fiber, comprising the following steps:

[0208] (1) Preparation of raw materials:

[0209] TPU;

[0210] Radiation protection particles I: barium sulfate (BaSO4), average particle size 60nm;

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

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

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

[0214] BaSO4 and Ta2O5 were sequentially added to DMAC, and the dispersion was obtained by ultrasonic shearing.

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

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

[0217] TPU was dissolved in BaSO4 / Ta2O5 / DMAC dispersion, stirred at 150 rpm for 24 h, filtered, ultrasonicated at 100 W for 30 min, and allowed to stand for defoaming to obtain a core spinning solution with a mass volume ratio of TPU to DMAC of 2.5 g:10 ml;

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

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

[0220] Among them, after adding Ti3AlC2 powder to the HCl solution containing LiF, the concentration of Ti3AlC2 in the mixed solution was 0.06g / ml and the concentration of LiF was 0.09g / ml; the concentration of MXene / DMAC dispersion was 18mg / ml;

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

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

[0223] (6) The core layer spinning solution and the shell layer spinning solution were coaxially wet-spun to obtain nascent fibers after a coagulation bath. The nascent fibers were then immersed in deionized water for 12 hours, then taken out and frozen at -20 ° C for 12 hours, and finally freeze-dried for 24 hours to obtain micro-gear-shaped, special-shaped, stretchable, conductive, and radiation-proof fibers.

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

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

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

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

[0228] The final micro-gear-shaped stretchable conductive radiation-proof fiber has a core-shell structure. The core layer cross section is circular, and the shell layer cross section is a micro-gear-shaped structure. The average height of the gear protrusion is 32.2µm and the average width is 21.5µm. Both the core layer substrate and the shell layer substrate are TPU. The surface of the core layer substrate has an interlaced micron-scale pore structure. BaSO4 and Ta2O5 are uniformly dispersed in the micron-scale pore structure, and MXene is uniformly dispersed in the shell layer substrate. The average diameter of the conductive radiation-proof fiber is 498µm, and the average thickness of the shell is 37.6μm; the elongation at break of the micro-gear-shaped special-shaped stretchable conductive radiation-proof fiber is 515%, and the conductivity is 175S / m; the strain sensing range of the micro-gear-shaped special-shaped stretchable conductive radiation-proof fiber is 0~290%, and the sensitivity range is 0~31565; after 2000 stretching cycles of a single micro-gear-shaped special-shaped stretchable conductive radiation-proof fiber under 0~50% strain, the resistance drift is 2.9%.

[0229] The micro-gear-shaped special-shaped stretchable conductive radiation-proof fiber is 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 stretchable multifunctional fabric has a shielding efficiency of 93.9% against X-rays.

Claims

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

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

3. The method for preparing a micro-gear-shaped special-shaped stretchable conductive radiation-proof fiber according to claim 2, characterized in that: During coaxial wet spinning, the inner and outer needle diameters were 0.4 mm and 1.07 mm, respectively, and the spinning tube length was 25–30 cm. The core layer injection rate was 0.1–0.3 ml / min. The coagulation bath temperature is 25~30℃, and the coagulation bath immersion time is 3~5h; after coagulation and forming, it is first washed with water and then freeze-dried.

4. The method for preparing a micro-gear-shaped special-shaped stretchable conductive radiation-proof fiber according to claim 1, characterized in that: The preparation process of the radiation-proof particle I / radiation-proof particle II / organic solvent dispersion is: adding radiation-proof particles I and radiation-proof particles II to the organic solvent in sequence, and obtaining the radiation-proof particle I / radiation-proof particle II / organic solvent dispersion by ultrasonic shear dispersion.

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

6. The method for preparing a micro-gear-shaped special-shaped stretchable conductive radiation-proof 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 a HCl solution containing LiF and stirred for reaction for 24 hours. Then, the reaction mixture is centrifuged, the lower precipitate is retained and repeatedly washed with water until the solution is neutral. Then, the solvent replacement method is used to remove the upper liquid by centrifugation, and then an organic solvent is added and centrifuged to obtain a MXene / organic solvent dispersion.

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

8. A micro-gear-shaped, special-shaped, stretchable conductive radiation-proof 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 shell cross section. The average height of the gear protrusions is 20-50µm, and the average width is 10-55µm. Both the core layer substrate and the shell layer substrate are TPU. The surface of the core layer substrate has an interlaced micron-scale pore structure, in which radiation-proof particles I and radiation-proof particles II are evenly dispersed, and MXene is evenly dispersed in the shell layer substrate.

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

10. The micro-gear-shaped special-shaped stretchable conductive radiation-proof fiber according to claim 9, characterized in that: The strain sensing range of the micro-gear-shaped special-shaped stretchable conductive fiber is 0~297%, and the sensitivity range is 0~32483; after 2000 stretching cycles of the micro-gear-shaped special-shaped stretchable conductive radiation-proof fiber under 0~50% strain, the resistance drift is 2~5%.

11. Use of the micro-gear-shaped, special-shaped, stretchable conductive radiation-proof fiber according to any one of claims 8 to 10, characterized in that: It is processed into stretchable multifunctional fabric using 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 shielding efficiency of stretchable multifunctional fabric against X-rays is over 90%.

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