Self-healing aramid fiber / polyurethane composite fiber as well as preparation method and application thereof
By preparing a mixture of plasma-activated aramid and waterborne polyurethane with a hierarchical porous structure, the problems of poor performance and difficulty in recycling of high-performance fiber materials were solved, and a self-healing and biodegradable high-strength composite fiber was realized.
Patent Information
- Application Number
- CN202511012529.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-22
- Publication Date
- 2025-12-02
AI Technical Summary
Existing high-performance fiber materials suffer from poor performance, limited application areas, and difficulties in recycling.
Plasma-activated aramid fibers were mixed with waterborne polyurethane, and EGDP/AIBN, 4-carboxyphenylboronic acid/sorbitol and FeCl3/dopamine hydrochloride solution were added to form a dynamic network of disulfide bonds, dynamic borate ester bonds and metal coordination bonds. Combined with microfluidic spinning and a three-stage coagulation bath, self-healing composite fibers with a hierarchical porous structure were prepared.
It achieves high strength, high toughness, and self-healing properties of the fiber, can degrade under acidic conditions, has good recyclability and high porosity, and improves fracture toughness by 2 to 3 times.
Smart Images
Figure CN121046992A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of composite fiber technology, specifically to a self-healing aramid / polyurethane composite fiber, its preparation method, and its application. Background Technology
[0002] Traditional fiber materials suffer from several drawbacks, including outdated production processes. While the production processes for traditional fiber materials are relatively mature, they still present challenges such as high energy consumption, heavy pollution, and low production efficiency. Furthermore, the low added value of these products makes it difficult to meet the demands of the high-end market. High-performance fibers, on the other hand, are special fibers possessing superior properties such as high strength, high modulus, high temperature resistance, corrosion resistance, flame retardancy, and outstanding chemical stability. These fibers are prepared through modification and composite technologies to meet the needs of various application scenarios.
[0003] However, high-performance fiber materials have many problems: 1. Insufficient technological maturity and poor product performance; 2. High-performance fibers often have relatively simple properties, which limits their application areas; 3. The recycling technology of composite materials is not yet mature, the recycling cost is high, and the technology route for the reuse of recycled materials has not been fully developed. Summary of the Invention
[0004] In view of the technical problems existing in the background art, this application provides a self-healing aramid / polyurethane composite fiber, its preparation method and application, aiming to solve the problems of poor performance, relatively single performance and difficulty in recycling of existing high-performance fiber products.
[0005] In a first aspect, this application provides a self-healing aramid / polyurethane composite fiber, its preparation method, and its application, comprising the following steps:
[0006] S1. Preparation of plasma-activated aramid fibers;
[0007] S2. Dissolve the plasma-activated aramid in an NMP / CaCl2 mixed solution, and then degas and filter it to obtain an aramid spinning solution;
[0008] S3. The aramid spinning solution is mixed with an aqueous polyurethane solution, and then EGDP / AIBN mixed solution, 4-carboxyphenylboronic acid / sorbitol mixed solution, and FeCl3 / dopamine hydrochloride mixed solution are added sequentially to obtain a mixed spinning solution;
[0009] S4. The mixed spinning solution is extruded through a microfluidic spinning head, passed through a temperature gradient control zone, then formed in a three-stage coagulation bath, and then dried to obtain a self-healing aramid / polyurethane composite fiber.
[0010] In the technical solution of this application embodiment, plasma-activated aramid is mixed with waterborne polyurethane, and then EGDP / AIBN mixed solution, phenylboronic acid / sorbitol mixed solution and Fe are added sequentially. 3+ A mixed spinning solution with a dopamine mixture was obtained, featuring a triple dynamic network synergistic enhancement of disulfide bonds, dynamic borate ester bonds, and metal coordination bonds. Microfluidic gradient spinning technology, combined with a three-stage coagulation bath, yielded a self-healing composite fiber with a hierarchical porous structure. Among these components, Fe... 3+ - Dopamine coordination bonds penetrate the matrix as permanent cross-linking points: their ends are connected to disulfide bonds and borate ester bonds, respectively, bearing the main load and inhibiting crack propagation. Based on this, the disulfide bonds, with the rigid support of the coordination bonds, dissipate energy through reversible fracture-recombination synergistically in stress concentration areas, achieving rapid self-repair of microcracks. Simultaneously, the borate ester bonds, through synergistic effects with the coordination bonds, significantly enhance the biodegradability of the groups; as sacrificial bonds, they can selectively break under strong acids or high temperatures, triggering overall fiber dissociation and completing closed-loop recycling. Combining microfluidic gradient spinning and a three-stage coagulation bath, the composite fibers can possess a hierarchical porous structure, promoting multi-level branching of cracks at the mesopore walls and significantly extending the crack path; simultaneously, Fe enriched on the pore wall surface... 3+ - The dopamine coordination bond and the disulfide bond form a "rigid-reversible" interface, which converts local stress into energy dissipation, thereby increasing the fiber fracture toughness by 2 to 3 times.
[0011] In some embodiments, in step S2, the mass concentration of CaCl2 in the NMP / CaCl2 mixed solution is 3-7 wt%, and the mass concentration of aramid in the aramid spinning solution is 10-14 wt%.
[0012] In some embodiments, in step S3, the volume ratio of the aramid spinning solution to the aqueous polyurethane is 1:1, and the mass fraction of the aqueous polyurethane in the aqueous polyurethane solution is 25%.
[0013] In this embodiment, mixing a specific ratio of aramid spinning solution with an aqueous polyurethane solution allows for thorough cross-linking of the two in the subsequent process, resulting in composite fibers with better performance.
[0014] In some embodiments, in step S3, the mass concentrations of EGDP and AIBN in the mixed spinning solution are 2 wt% and 0.5 wt%, respectively; the mass concentrations of 4-carboxyphenylboronic acid and sorbitol in the mixed spinning solution are 1.5 wt% and 0.8 wt%, respectively; and the mass concentrations of FeCl3 and dopamine hydrochloride in the mixed spinning solution are 3 wt% and 2 wt%, respectively.
[0015] In this embodiment, disulfide bonds, borate ester bonds, and metal-coordination bonds are precisely introduced at this concentration, and the three work together to construct a dynamic cross-linking network: which not only endows the fiber with high strength and toughness, but also enables microcrack self-healing, high temperature / acid-triggered degradation and recycling, and further enhances heat resistance and interface stability with the help of dopamine-iron coordination.
[0016] In some embodiments, in step S4, the temperature settings of the temperature gradient control zone are 25°C, 35°C, 45°C, and 60°C respectively, from 25°C to 60°C.
[0017] In this embodiment, solvent is removed stepwise through a four-level gradient from 25 to 60°C and phase separation is induced, which first densifies the skin layer and then solidifies the core layer to form radial hierarchical pores. At the same time, the temperature is gently raised to activate disulfide bond exchange and borate ester pre-crosslinking, laying the structural foundation for subsequent self-healing and controllable degradation.
[0018] In some embodiments, in step S4, the channel of the microfluidic spinning head is Y-shaped, and the inner wall of the microfluidic spinning head has a nano-SiO2 coating.
[0019] In this embodiment, the Y-shaped microfluidic spinning head realizes the laminar flow structure of aramid and polyurethane pre-separation-re-convergence. The nano-SiO2 coating on the inner wall reduces adhesion and inhibits agglomeration, ensuring uniform coaxial extrusion of multiple components and maintaining a stable Taylor cone, thereby obtaining multi-level porous composite fibers with uniform diameter and clear interface.
[0020] In some embodiments, in step S4, the three coagulation baths are a water bath, a 30% DMF bath, and an anhydrous ethanol bath, respectively.
[0021] In this embodiment, the skin is rapidly cured in a water bath, the solvent is slowly released in a 30% DMF bath to form mesopores, and the residual solvent is completely removed and the pore structure is fixed in an anhydrous ethanol bath. The three-level gradient solidification synergistically constructs interconnected multi-level pores, improves the specific surface area and the accessibility of dynamic bonds, and takes into account both high strength and toughness and self-healing.
[0022] In some embodiments, the anhydrous ethanol bath contains graphene quantum dots with a mass concentration of 0.1 wt%.
[0023] In this embodiment, 0.1 wt% of graphene quantum dots are infiltrated into the pore walls with ethanol to construct a thermally / electrically conductive network, accelerating dynamic bond thermal response and crack self-healing; at the same time, as a nano-reinforcing phase, it improves fiber modulus and interface strength.
[0024] Secondly, this application provides a self-healing aramid / polyurethane composite fiber, prepared using the aforementioned method. The self-healing aramid / polyurethane composite fiber has a tensile strength of 16–20 MPa, recovers 95% of its original strength within 30 minutes after fracture, completely degrades within 2 hours at pH 3, has a porosity of 30–70%, and a specific surface area ≥200 m². 2 / g.
[0025] In the technical solution of this application embodiment, the self-healing aramid / polyurethane composite fiber has good mechanical properties and self-healing effect. It can decompose under acidic conditions, is recyclable, and has high porosity, resulting in low sheet resistance.
[0026] Thirdly, this application provides an application of self-healing aramid / polyurethane composite fiber, wherein the aforementioned self-healing aramid / polyurethane composite fiber is applied to self-healing medical dressings, which can repair circuit substrates.
[0027] In the technical solution of this application embodiment, the self-healing aramid / polyurethane composite fiber first uses plasma technology to efficiently activate and dissolve the aramid, and then introduces a synergistic network of disulfide bonds, borate ester bonds and metal coordination bonds at the molecular level, so that the fiber has self-healing, biodegradability and high strength and toughness. Finally, a multi-level porous structure is constructed by microfluidic spinning combined with a three-stage coagulation bath, which amplifies the chemical advantages of the front end to the macroscopic fiber, realizing high-performance and sustainable integrated preparation.
[0028] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description
[0029] To more clearly illustrate the technical solutions of this application, the accompanying drawings used in this application will be briefly described below. Obviously, the drawings described below are merely some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without any creative effort.
[0030] Figure 1 This is a schematic diagram of the spinning process of the self-healing aramid / polyurethane composite fiber prepared in Example 1.
[0031] Figure 2 This is a SEM image of the self-healing aramid / polyurethane composite fiber prepared in Example 1.
[0032] Figure 3The image shows the self-healing aramid / polyurethane composite fiber prepared in Example 1 under an electron microscope.
[0033] Figure 4 The tensile breaking strength diagrams are for the self-healing aramid / polyurethane composite fibers prepared in Example 1 and Comparative Examples 1-3. Detailed Implementation
[0034] The embodiments of the technical solution of this application are described in detail below. The following embodiments are only used to illustrate the technical solution of this application more clearly, and are therefore only examples, and should not be used to limit the scope of protection of this application.
[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terms “comprising” and “having” and any variations thereof as used herein are for the purpose of describing particular embodiments only and are not intended to limit this application.
[0036] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.
[0037] To address the issues of poor performance, limited performance characteristics, and difficulties in recycling existing high-performance fiber products, this application provides a self-healing aramid / polyurethane composite fiber, its preparation method, and its applications. This application involves mixing plasma-activated aramid with aqueous polyurethane, followed by the sequential addition of an EGDP / AIBN mixed solution, a phenylboronic acid / sorbitol mixed solution, and Fe... 3+ A mixed spinning solution with a dopamine mixture was obtained, featuring a triple dynamic network synergistic enhancement of disulfide bonds, dynamic borate ester bonds, and metal coordination bonds. Microfluidic gradient spinning technology, combined with a three-stage coagulation bath, yielded a self-healing composite fiber with a hierarchical porous structure. Among these components, Fe... 3+- Dopamine coordination bonds penetrate the matrix as permanent cross-linking points: their ends are connected to disulfide bonds and borate ester bonds, respectively, bearing the main load and inhibiting crack propagation. Based on this, the disulfide bonds, with the rigid support of the coordination bonds, dissipate energy through reversible fracture-recombination synergistically in stress concentration areas, achieving rapid self-repair of microcracks. Simultaneously, the borate ester bonds, through synergistic effects with the coordination bonds, significantly enhance the biodegradability of the groups; as sacrificial bonds, they can selectively break under strong acids or high temperatures, triggering overall fiber dissociation and completing closed-loop recycling. Combining microfluidic gradient spinning and a three-stage coagulation bath, the composite fibers can possess a hierarchical porous structure, promoting multi-level branching of cracks at the mesopore walls and significantly extending the crack path; simultaneously, Fe enriched on the pore wall surface... 3+ - The dopamine coordination bond and the disulfide bond form a "rigid-reversible" interface, which converts local stress into energy dissipation, thereby increasing the fiber fracture toughness by 2 to 3 times.
[0038] This application provides a method for preparing self-healing aramid / polyurethane composite fibers, comprising the following steps:
[0039] S1. Preparation of plasma-activated aramid fibers;
[0040] S2. Dissolve the plasma-activated aramid in an NMP / CaCl2 mixed solution, and then degas and filter it to obtain an aramid spinning solution;
[0041] S3. The aramid spinning solution is mixed with an aqueous polyurethane solution, and then EGDP / AIBN mixed solution, 4-carboxyphenylboronic acid / sorbitol mixed solution, and FeCl3 / dopamine hydrochloride mixed solution are added sequentially to obtain a mixed spinning solution;
[0042] S4. The mixed spinning solution is extruded through a microfluidic spinning head, passed through a temperature gradient control zone, then formed in a three-stage coagulation bath, and then dried to obtain a self-healing aramid / polyurethane composite fiber.
[0043] In the technical solution of this application embodiment, plasma-activated aramid is mixed with waterborne polyurethane, and then EGDP / AIBN mixed solution, phenylboronic acid / sorbitol mixed solution and Fe are added sequentially. 3+ A mixed spinning solution with a dopamine mixture was obtained, featuring a triple dynamic network synergistic enhancement of disulfide bonds, dynamic borate ester bonds, and metal coordination bonds. Microfluidic gradient spinning technology, combined with a three-stage coagulation bath, yielded a self-healing composite fiber with a hierarchical porous structure. Among these components, Fe... 3+- Dopamine coordination bonds penetrate the matrix as permanent cross-linking points: their ends are connected to disulfide bonds and borate ester bonds, respectively, bearing the main load and inhibiting crack propagation. Based on this, the disulfide bonds, with the rigid support of the coordination bonds, dissipate energy through reversible fracture-recombination synergistically in stress concentration areas, achieving rapid self-repair of microcracks. Simultaneously, the borate ester bonds, through synergistic effects with the coordination bonds, significantly enhance the biodegradability of the groups; as sacrificial bonds, they can selectively break under strong acids or high temperatures, triggering overall fiber dissociation and completing closed-loop recycling. Combining microfluidic gradient spinning and a three-stage coagulation bath, the composite fibers can possess a hierarchical porous structure, promoting multi-level branching of cracks at the mesopore walls and significantly extending the crack path; simultaneously, Fe enriched on the pore wall surface... 3+ - The dopamine coordination bond and the disulfide bond form a "rigid-reversible" interface, which converts local stress into energy dissipation, thereby increasing the fiber fracture toughness by 2 to 3 times.
[0044] Furthermore, in some embodiments, in step S1, the preparation method of the plasma-activated aramid includes the following steps: placing the shredded aramid in a reaction chamber, evacuating to 5×10-2 Pa, then introducing argon gas (purity 99.999%) to a working pressure of 10 Pa, reacting for 120 min to obtain plasma-activated aramid.
[0045] Furthermore, in some embodiments, in step S2, the mass concentration of CaCl2 in the NMP / CaCl2 mixed solution is 3-7 wt%, and the mass concentration of aramid in the aramid spinning solution is 10-14 wt%.
[0046] Furthermore, in some embodiments, in step S3, the volume ratio of the aramid spinning solution to the aqueous polyurethane is 1:1, and the mass fraction of the aqueous polyurethane in the aqueous polyurethane solution is 25%.
[0047] In the technical solution of this application embodiment, mixing a specific ratio of aramid spinning solution with an aqueous polyurethane solution enables the two to fully crosslink in the subsequent process, resulting in composite fibers with better performance.
[0048] Further, in some embodiments, in step S3, the mass concentrations of EGDP and AIBN in the mixed spinning solution are 2 wt% and 0.5 wt%, respectively; the mass concentrations of 4-carboxyphenylboronic acid and sorbitol in the mixed spinning solution are 1.5 wt% and 0.8 wt%, respectively; and the mass concentrations of FeCl3 and dopamine hydrochloride in the mixed spinning solution are 3 wt% and 2 wt%, respectively.
[0049] In the technical solution of this application embodiment, disulfide bonds, borate ester bonds and metal-coordination bonds are precisely introduced according to the concentration, and the three work together to construct a dynamic cross-linking network: which not only endows the fiber with high strength and toughness, but also realizes microcrack self-healing, high temperature / acid triggered degradation and recycling, and further enhances heat resistance and interface stability with the help of dopamine-iron coordination.
[0050] Furthermore, in some embodiments, in step S4, the temperature setting of the temperature gradient control zone is 25°C, 35°C, 45°C, and 60°C respectively, from 25°C to 60°C.
[0051] In the technical solution of this application embodiment, the solvent is removed stepwise by a four-level gradient from 25 to 60°C and phase separation is induced, so that the skin layer is first densified and the core layer is then cured, forming radial multi-level pores; at the same time, the temperature is gently raised to activate the disulfide bond exchange and the pre-crosslinking of borate ester, laying the structural foundation for subsequent self-healing and controllable degradation.
[0052] Furthermore, in some embodiments, in step S4, the channel of the microfluidic spinning head is Y-shaped, and the inner wall of the microfluidic spinning head has a nano-SiO2 coating.
[0053] In the technical solution of this application embodiment, the Y-type microfluidic spinning head realizes the laminar flow structure of aramid and polyurethane pre-separation-re-convergence. The nano-SiO2 coating on the inner wall reduces adhesion and inhibits agglomeration, ensuring uniform coaxial extrusion of multiple components and maintaining a stable Taylor cone, thereby obtaining multi-level porous composite fibers with uniform diameter and clear interface.
[0054] Furthermore, in some embodiments, in step S4, the three coagulation baths are a water bath, a 30% DMF bath, and an anhydrous ethanol bath, respectively.
[0055] In the technical solution of this application embodiment, the skin layer is rapidly cured in a water bath, the solvent is slowly released in a 30% DMF bath to form mesopores, and the residual solvent is completely removed and the pore structure is fixed in an anhydrous ethanol bath. The three-level gradient solidification synergistically constructs interconnected multi-level pores, improves the specific surface area and dynamic bond accessibility, and takes into account both high strength and toughness and self-healing.
[0056] Furthermore, in some embodiments, in step S4, the anhydrous ethanol bath contains graphene quantum dots with a mass concentration of 0.1 wt%.
[0057] In the technical solution of this application embodiment, 0.1 wt% of graphene quantum dots are infiltrated into the pore walls with ethanol to construct a thermally / electrically conductive network, which accelerates dynamic bond thermal response and crack self-repair; at the same time, it serves as a nano-reinforcing phase to improve fiber modulus and interface strength.
[0058] Secondly, this application provides a self-healing aramid / polyurethane composite fiber, prepared using the aforementioned method. The self-healing aramid / polyurethane composite fiber has a tensile strength of 16–20 MPa, recovers 95% of its original strength within 30 minutes after fracture, completely degrades within 2 hours at pH 3, has a porosity of 30–70%, and a specific surface area ≥200 m². 2 / g.
[0059] In the technical solution of this application embodiment, the self-healing aramid / polyurethane composite fiber has good mechanical properties and self-healing effect. It can decompose under acidic conditions, is recyclable, and has high porosity, resulting in low sheet resistance.
[0060] Thirdly, this application provides an application of self-healing aramid / polyurethane composite fiber, wherein the aforementioned self-healing aramid / polyurethane composite fiber is applied to self-healing medical dressings, which can repair circuit substrates.
[0061] In the technical solution of this application embodiment, the self-healing aramid / polyurethane composite fiber first uses plasma technology to efficiently activate and dissolve the aramid, and then introduces a synergistic network of disulfide bonds, borate ester bonds and metal coordination bonds at the molecular level, so that the fiber has self-healing, biodegradability and high strength and toughness. Finally, a multi-level porous structure is constructed by microfluidic spinning combined with a three-stage coagulation bath, which amplifies the chemical advantages of the front end to the macroscopic fiber, realizing high-performance and sustainable integrated preparation.
[0062] The following are some specific embodiments. It should be noted that the embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they shall be performed in accordance with the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.
[0063] Example 1
[0064] This embodiment provides a method for preparing self-healing aramid / polyurethane composite fibers, specifically including the following steps:
[0065] (1) Place the shredded aramid in the reaction chamber, evacuate to 5×10-2Pa, then introduce argon gas (purity 99.999%) to the working pressure of 10Pa, react for 120min to obtain plasma-activated aramid.
[0066] (2) The plasma-activated aramid was dissolved in a NMP / CaCl2 mixed solution with a mass concentration of 5 wt%, and then degassed and filtered to obtain an aramid spinning solution with a mass concentration of 12 wt%.
[0067] (3) The above aramid spinning solution was mixed with a 25% aqueous polyurethane solution at a volume ratio of 1:1. Then, an EGDP / AIBN mixed solution, a 4-carboxyphenylboronic acid / sorbitol mixed solution, and a FeCl3 / dopamine hydrochloride mixed solution were added sequentially to obtain a mixed spinning solution. The mass concentrations of EGDP and AIBN in the mixed spinning solution were 2 wt% and 0.5 wt%, respectively; the mass concentrations of 4-carboxyphenylboronic acid and sorbitol were 1.5 wt% and 0.8 wt%, respectively; and the mass concentrations of FeCl3 and dopamine hydrochloride were 3 wt% and 2 wt%, respectively.
[0068] (4) Figure 1 As shown, the above mixed spinning solution is extruded through a Y-shaped microfluidic spinning head with a nano-SiO2 coating on the inner wall, and then passed through a temperature gradient from 25℃ to 60℃, namely 25℃, 35℃, 45℃, and 60℃, and then passed through a water bath, a 30% DMF bath, and an anhydrous ethanol bath in sequence, and then dried to obtain self-healing aramid / polyurethane composite fiber.
[0069] SEM image of the self-healing aramid / polyurethane composite fiber prepared in this embodiment, as shown below. Figure 2 .
[0070] Depend on Figure 2 The SEM images show that the prepared self-healing aramid / polyurethane composite fiber has a porous structure.
[0071] Figure 3 This is a self-healing image of the self-healing aramid / polyurethane composite fiber prepared in this embodiment under an electron microscope.
[0072] Depend on Figure 3 It can be seen that the composite fiber has good self-healing properties.
[0073] Comparative Examples 1-3
[0074] Comparative Examples 1 to 3 provide a method for preparing self-healing aramid / polyurethane composite fibers. Compared with Example 1, the difference is that in step (3), Comparative Example 1 only adds EGDP / AIBN mixed solution, Comparative Example 2 only adds 4-carboxyphenylboronic acid / sorbitol mixed solution, and Comparative Example 3 only adds FeCl3 / dopamine hydrochloride mixed solution. Other steps are roughly the same as in Example 1, and will not be repeated here.
[0075] The properties of the self-healing aramid / polyurethane composite fibers prepared in Examples 1 and Comparative Examples 1-3 are shown in Table 1. The tensile breaking strength diagrams of the self-healing aramid / polyurethane composite fibers prepared in Examples 1 and Comparative Examples 1-3 are shown in... Figure 4 As shown.
[0076] Table 1. Properties of self-healing aramid / polyurethane composite fibers prepared in Comparative Examples 1-3
[0077] Examples / Comparative Examples Example 1 Comparative Example 1 Comparative Example 2 Comparative Example 3 Self-healing efficiency (%) 95 90 70 50 Tensile breaking strength (MPa) 18.3 13.2 15.1 16.9
[0078] As can be seen from Table 1, due to the synergistic effect of the three bond energies, the self-healing efficiency of Example 1 is significantly higher than that of the comparative example. It can recover to 95% of the original strength within half an hour, and the tensile fracture strength also reaches 18.3 MPa, which is significantly higher than that of the comparative example.
[0079] In summary, this application provides a self-healing aramid / polyurethane composite fiber, its preparation method, and its application. This application involves mixing plasma-activated aramid with aqueous polyurethane, followed by the sequential addition of an EGDP / AIBN mixed solution, a phenylboronic acid / sorbitol mixed solution, and Fe... 3+ A mixed spinning solution with a dopamine mixture was obtained, featuring a triple dynamic network synergistic enhancement of disulfide bonds, dynamic borate ester bonds, and metal coordination bonds. This solution was then used in conjunction with microfluidic gradient spinning technology and a three-stage coagulation bath to produce self-healing composite fibers with a hierarchical porous structure. Fe 3+ - Dopamine coordination bonds penetrate the matrix as permanent cross-linking points: their ends are connected to disulfide bonds and borate ester bonds, respectively, bearing the main load and inhibiting crack propagation. Based on this, the disulfide bonds, with the rigid support of the coordination bonds, dissipate energy through reversible fracture-recombination synergistically in stress concentration areas, achieving rapid self-repair of microcracks. Simultaneously, the borate ester bonds, through synergistic effects with the coordination bonds, significantly enhance the biodegradability of the groups; as sacrificial bonds, they can selectively break under strong acids or high temperatures, triggering overall fiber dissociation and completing closed-loop recycling. Combining microfluidic gradient spinning and a three-stage coagulation bath, the composite fibers can possess a hierarchical porous structure, promoting multi-level branching of cracks at the mesopore walls and significantly extending the crack path; simultaneously, Fe enriched on the pore wall surface... 3+ - The dopamine coordination bond and the disulfide bond form a "rigid-reversible" interface, which converts local stress into energy dissipation, thereby increasing the fiber fracture toughness by 2 to 3 times.
[0080] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.
Claims
1. A method for preparing self-healing aramid / polyurethane composite fibers, characterized in that, Includes the following steps: S1. Preparation of plasma-activated aramid fibers; S2. Dissolve the plasma-activated aramid in an NMP / CaCl2 mixed solution, and then degas and filter it to obtain an aramid spinning solution; S3. The aramid spinning solution is mixed with an aqueous polyurethane solution, and then EGDP / AIBN mixed solution, 4-carboxyphenylboronic acid / sorbitol mixed solution, and FeCl3 / dopamine hydrochloride mixed solution are added sequentially to obtain a mixed spinning solution; S4. The mixed spinning solution is extruded through a microfluidic spinning head, passed through a temperature gradient control zone, then formed in a three-stage coagulation bath, and then dried to obtain a self-healing aramid / polyurethane composite fiber.
2. The method for preparing self-healing aramid / polyurethane composite fibers according to claim 1, characterized in that, In step S2, the mass concentration of CaCl2 in the NMP / CaCl2 mixed solution is 3-7 wt%, and the mass concentration of aramid in the aramid spinning solution is 10-14 wt%.
3. The method for preparing self-healing aramid / polyurethane composite fibers according to claim 1, characterized in that, In step S3, the volume ratio of the aramid spinning solution to the aqueous polyurethane solution is 1:1, and the mass fraction of the aqueous polyurethane in the aqueous polyurethane solution is 25%.
4. The method for preparing self-healing aramid / polyurethane composite fibers according to claim 1, characterized in that, In step S3, the mass concentrations of EGDP and AIBN in the mixed spinning solution are 2 wt% and 0.5 wt%, respectively; the mass concentrations of 4-carboxyphenylboronic acid and sorbitol in the mixed spinning solution are 1.5 wt% and 0.8 wt%, respectively; and the mass concentrations of FeCl3 and dopamine hydrochloride in the mixed spinning solution are 3 wt% and 2 wt%, respectively.
5. The method for preparing self-healing aramid / polyurethane composite fibers according to claim 1, characterized in that, In step S4, the temperature settings of the temperature gradient control zone are 25℃, 35℃, 45℃, and 60℃ respectively, from 25℃ to 60℃.
6. The method for preparing self-healing aramid / polyurethane composite fiber according to claim 1, characterized in that, In step S4, the channel of the microfluidic spinning head is Y-shaped, and the inner wall of the microfluidic spinning head has a nano-SiO2 coating.
7. The method for preparing self-healing aramid / polyurethane composite fiber according to claim 1, characterized in that, In step S4, the three coagulation baths are a water bath, a 30% DMF bath, and an anhydrous ethanol bath, respectively.
8. The method for preparing self-healing aramid / polyurethane composite fiber according to claim 7, characterized in that, The anhydrous ethanol bath contains graphene quantum dots with a mass concentration of 0.1 wt%.
9. A self-healing aramid / polyurethane composite fiber, characterized in that, The self-healing aramid / polyurethane composite fiber is prepared using the preparation method described in claims 1-8; the self-healing aramid / polyurethane composite fiber has a tensile strength of 16-20 MPa, can recover 95% of its original strength within 30 minutes after fracture, completely degrades within 2 hours under pH=3 conditions, has a porosity of 30-70%, and a specific surface area ≥200 m². 2 / g.
10. An application of a self-healing aramid / polyurethane composite fiber, characterized in that, The self-healing aramid / polyurethane composite fiber described in claim 9 is used in self-healing medical dressings to repair circuit substrates.