High-strength self-repairing polyvinyl alcohol fiber, preparation method and application thereof

Abstract

The application belongs to the technical field of high-performance fiber materials, and discloses a high-strength self-repairing polyvinyl alcohol fiber, a preparation method and application. By introducing collagen peptide into a PVA / boric acid dynamic crosslinking system, the hydration plasticizing effect and amorphous structure regulation effect of the collagen peptide are utilized to construct a two-phase structure cooperation of an amorphous collagen peptide dispersed phase and a boric acid ester dynamic crosslinking network in the amorphous region of a PVA crystalline continuous phase. The structure realizes 82% strength recovery rate under the condition of 20 DEG C normal temperature water triggering while maintaining ultrahigh strength, and for the first time, >700 MPa ultrahigh strength and >80% mild self-repairing efficiency are simultaneously obtained in a PVA-based fiber, thereby solving the long-standing problem of mutual contradiction between high strength and repair performance in the prior art.

Description

Technical Field

[0001] This invention relates to the field of high-performance fiber materials technology, and in particular to high-strength self-healing polyvinyl alcohol fiber, its preparation method, and its application. Background Technology

[0002] With the rapid development of flexible electronics, smart textiles, wearable sensors, and biomedical devices, high-performance fiber materials not only need to possess excellent mechanical properties to meet structural load-bearing requirements, but also need to have the ability to self-heal under long-term service conditions to improve material lifespan and system reliability. Currently, self-healing fiber materials are mainly divided into two categories: externally induced self-healing systems and intrinsically self-healing systems.

[0003] Externally-assisted self-healing systems typically encapsulate repair agents using microcapsules, microchannels, or coaxial fiber structures, releasing the repair agent to achieve healing when the fiber is damaged. However, this type of technology has inherent drawbacks such as one-time consumption of the repair agent, non-repeatable repair capabilities, complex preparation processes, and difficulty in large-scale production, failing to meet the practical application requirements for recyclable material repair. Intrinsic self-healing systems mainly rely on dynamic covalent bonds or supramolecular interactions to achieve self-repair after material damage. Currently common dynamic bonds include Diels-Alder bonds, disulfide bonds, imine bonds, and borate ester bonds. However, these dynamic bonds have significant limitations in practical applications: Diels-Alder systems typically require heating to 60-120°C for reverse reactions and recombination, making them unsuitable for human environments and wearable devices; disulfide bond systems rely on redox environments or catalysts, resulting in low repair efficiency in natural environments; imine bond systems, while capable of dynamic exchange at room temperature, are prone to hydrolysis and failure in high-humidity environments; and although borate ester bonds possess good biocompatibility and water-responsive properties, current research mainly focuses on hydrogels, elastomers, and soft polymer networks, whose mechanical strength is generally low (typically in the kPa to MPa range), making them unsuitable for use as structural load-bearing fibers.

[0004] To improve mechanical properties, researchers have attempted to introduce borate ester bonds into the polyvinyl alcohol (PVA) system to prepare high-strength fibers. PVA is a highly crystalline polymer with a large number of crystalline regions and a dense hydrogen bond network. While this gives the fibers high mechanical strength, it also leads to the following technical bottlenecks: (1) High crystallinity severely restricts the ability of chain segments to migrate. After the fiber breaks, the molecular chains are difficult to diffuse, and the dynamic bonds are difficult to contact and recombine, resulting in extremely low repair efficiency; (2) To overcome the limitation of chain segment movement, existing technologies usually require external stimulation such as heating, ultraviolet light irradiation, electrical stimulation, or chemical catalysts to achieve high repair efficiency, which cannot meet the self-repair requirements under normal temperature and mild conditions; (3) Strength and repair performance are difficult to balance. Reducing crystallinity can improve repair efficiency, but it will significantly sacrifice mechanical properties. While increasing crystallinity can enhance strength, it makes it more difficult for dynamic bonds to exchange. Therefore, how to achieve efficient self-repair under normal temperature and mild conditions while maintaining high strength load-bearing capacity is a key technical problem that urgently needs to be solved in the field of high-performance self-repairing fibers.

[0005] In view of this, the present invention is proposed. Summary of the Invention

[0006] The present invention aims to solve at least one of the above technical problems, and provides high-strength self-healing polyvinyl alcohol fiber, its preparation method and application.

[0007] To achieve the above objectives, the first technical solution adopted by the present invention is as follows: High-strength, self-healing polyvinyl alcohol (PVA) fiber is produced by wet spinning and low-temperature drying of a spinning solution containing PVA, collagen peptides, and boric acid. The fiber possesses a supramolecular interaction system, including: Crystallization-oriented polyvinyl alcohol phase; Collagen peptides dispersed in an amorphous state in the amorphous regions of the polyvinyl alcohol phase; and A dynamic cross-linked network of borate esters formed by boric acid, polyvinyl alcohol, and the hydroxyl groups of collagen peptides.

[0008] Preferably, by weight, the polyvinyl alcohol comprises 50-95 parts, the collagen peptide comprises 5-45 parts, and the boric acid comprises 1-5 parts; the average molecular weight of the collagen peptide is 2000-10000 Da.

[0009] Preferably, by weight, the composition is 63 parts polyvinyl alcohol, 35 parts collagen peptides, and 2 parts boric acid; the average molecular weight of the collagen peptides is 10,000 Da.

[0010] Preferably, the temperature for the low-temperature drying is 20~60℃.

[0011] The second technical solution adopted in this invention is: A method for preparing high-strength self-healing polyvinyl alcohol fibers includes: Polyvinyl alcohol, collagen peptides and boric acid are uniformly mixed to obtain a spinning solution; The spinning solution is wet-spun and drawn, and then dried at 20~60℃.

[0012] Preferably, the spinning solution contains 14-25% polyvinyl alcohol, 5-25% collagen peptides, and 0.5-5% boric acid.

[0013] Preferably, the coagulation bath for wet spinning is a saturated sodium sulfate solution with a pH of 9-14 and a temperature of 25-60°C.

[0014] Preferably, the drying is natural drying or hot air drying, and the drying time is 0.5 to 24 hours.

[0015] The third technical solution adopted in this invention is: Applications of high-strength self-healing polyvinyl alcohol fibers in the preparation of smart textiles, flexible electronic devices, biomedical dressings, or wearable devices.

[0016] Compared with the prior art, the present invention has the following beneficial effects: This invention introduces collagen peptides into a PVA / boronic acid dynamic crosslinking system, utilizing their hydration and plasticizing effects and amorphous structure regulation to construct a biphase structure combining an amorphous collagen peptide dispersion phase and a borate ester dynamic crosslinking network within the amorphous region of the continuous crystalline PVA phase. This structure maintains ultra-high strength while achieving an 82% strength recovery rate under water-triggered conditions at 20°C. For the first time, it simultaneously achieves ultra-high strength (>700 MPa) and a mild self-healing efficiency (>80%) in PVA-based fibers, resolving the long-standing problem of the contradiction between high strength and repair performance in existing technologies.

[0017] Unlike existing PVA-borate ester fibers that require heating, ultraviolet light, electrical stimulation, or chemical catalysts for repair, this invention utilizes the strong hydrophilic groups of collagen peptides to capture moisture in the environment, forming a high-density bound water layer at the fiber fracture interface. Through the local plasticization effect of the bound water, the activation energy of PVA chain segment migration and the dynamic bond exchange energy barrier are reduced, allowing the borate ester bonds to undergo reversible exchange and recombination under water contact conditions without any external stimulation. This is particularly suitable for the long-term service requirements of human body environments and wearable devices.

[0018] The fiber of this invention achieves highly efficient self-healing while maintaining ultra-high strength and high toughness. Its tensile strength reaches 703.86 MPa, far exceeding that of ordinary self-healing hydrogel materials (kPa to MPa level); its toughness reaches 1202.09 MJ / m. 3Compared to existing PVA fibers, this represents a 98.7% improvement. Small-angle X-ray scattering (SAXS) results show that the introduction of collagen peptides only moderately reduces the orientation of PVA, and the fibers still maintain a continuous phase skeleton with crystalline orientation, thus ensuring structural load-bearing capacity.

[0019] The fiber of this invention possesses ultra-high strength, high toughness, and self-healing capability triggered by room temperature water. It is suitable for fields such as smart textiles (self-healing flexible wire carriers), flexible electronic devices (recoverable high-strength electrode substrates), biomedical dressings (high-strength sutures or scaffolds that adhere to wounds for a long time), and wearable devices (structural fibers resistant to bending fatigue). It can significantly improve the reliability and service life of materials in complex service environments. Attached Figure Description

[0020] Figure 1 The FT-IR spectra of Example 1, Comparative Example 1, and Comparative Example 8 are shown below. Figure 2 Comparison diagrams of two-dimensional SAXS spectra and orientation factors for Example 1, Comparative Example 1, and Comparative Example 8; Figure 3 The graphs show the dynamic water adsorption (DVS) curves for Example 1 and Comparative Example 1. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. It should be understood that these descriptions are merely exemplary and not intended to limit the scope of the invention. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concept of the invention. Unless otherwise specified, specific conditions in the embodiments are performed under conventional conditions or conditions recommended by the manufacturer. Reagents or instruments used, unless otherwise specified, are all commercially available conventional products.

[0022] The first embodiment of the present invention provides a high-strength self-healing polyvinyl alcohol fiber, which is obtained by wet spinning and low-temperature drying of a spinning solution containing polyvinyl alcohol, collagen peptides and boric acid. The fiber has a supramolecular interaction system, including: Crystallization-oriented polyvinyl alcohol phase; Collagen peptides dispersed in an amorphous state in the amorphous regions of the polyvinyl alcohol phase; and A dynamic cross-linked network of borate esters formed by boric acid, polyvinyl alcohol, and the hydroxyl groups of collagen peptides.

[0023] The fiber, by weight, comprises 50-95 parts polyvinyl alcohol, 5-45 parts collagen peptides, and 1-5 parts boric acid. In a preferred embodiment, by weight, polyvinyl alcohol comprises 63 parts, collagen peptides 35 parts, and boric acid 2 parts. Polyvinyl alcohol serves as the continuous phase framework, providing the primary mechanical strength; collagen peptides are dispersed in an amorphous state in the amorphous region, capturing water through their strong hydrophilic groups to form a high-density bound water layer, thus exerting a hydration and plasticizing effect; boric acid forms a dynamic cross-linked network of borate esters with the hydroxyl groups of PVA and collagen peptides, endowing the fiber with reversible self-repair capabilities.

[0024] Polyvinyl alcohol (PVA) is a highly crystalline polymer with numerous crystalline regions and a dense network of hydrogen bonds. During wet spinning and drawing processes, PVA molecular chains align to form a crystalline oriented phase, constituting the fiber's skeletal structure and endowing the fiber with excellent mechanical load-bearing capacity.

[0025] The collagen peptides described in this invention are small molecule peptides obtained by partial hydrolysis of collagen, preferably with a molecular weight of 2000-10000 Da, more preferably about 10000 Da. Collagen peptides in this molecular weight range have smaller molecular size and higher chain segment mobility, enabling them to be more uniformly dispersed in the amorphous region of PVA. They also have a higher proportion of exposed active hydrophilic groups such as hydroxyl, amino, and amide groups on their molecular chains, thereby constructing a denser hydrogen bond network and significantly enhancing the hydration and plasticizing effect and water-locking capacity. It should be noted that the molecular weight of the collagen peptides has a significant impact on their hydration and plasticizing effect and the self-repairing properties of the fibers. When the molecular weight is too small, the peptide chain is too short. Although it is easy to disperse, it is difficult to form a stable and effective hydrogen bond network and a local high-density bound water layer in the amorphous region of PVA. It also cannot fully participate in the formation of the dynamic cross-linking network of borate esters, resulting in insufficient hydration and plasticization effect and reduced repair efficiency. When the molecular weight is too large, although the total amount of hydrophilic groups increases, the molecular chain mobility decreases, the steric hindrance increases, the dispersion uniformity in the amorphous region of PVA decreases, and the resistance to chain segment migration increases, which weakens the hydration and plasticization effect and reduces the self-repair efficiency.

[0026] Further research by the inventors revealed that within the range of 2000–10000 Da, the self-repair efficiency of collagen peptides decreased with increasing molecular weight. This is because while increasing molecular weight helps maintain a certain level of interchain entanglement, it also reduces the mobility of the molecular chains and the uniformity of dispersion in the amorphous region of PVA, leading to a weakening of the hydration and plasticization effect.

[0027] Collagen peptides have an amorphous structure. This invention employs a low-temperature drying process, preserving the collagen peptides in their amorphous state within the fiber, thus retaining their active hydrophilic groups. If high-temperature setting is used, the collagen peptides will undergo high-temperature degradation or cross-linking, destroying the active hydrophilic groups and losing their hydration and plasticizing capabilities. The collagen peptide molecular chain contains numerous hydroxyl, amino, and amide groups, enabling the formation of a stable, high-density bound water layer. The introduction of collagen peptides provides additional hydrogen bond donors for the fiber system of this invention, strengthening the supramolecular interactions between the ternary components.

[0028] The boronic ester dynamic cross-linking network is formed by the reversible condensation reaction of boric acid with hydroxyl groups on PVA and collagen peptide molecular chains (B–O–C bonds). This cross-linking network provides structural stability in the intact fiber state; after fiber breakage and the interface is affected by water molecules, the boronic ester bonds undergo a reversible exchange reaction. This allows the broken molecular chains to re-entangle and form a new cross-linked network, thereby achieving efficient self-repair under normal temperature conditions.

[0029] The self-repair function of the fiber of this invention depends on the synergistic effect of the hydration and plasticization effect of collagen peptides and the dynamic cross-linking network of borate esters. Its mechanism can be divided into four stages: Phase 1: Localized Water Absorption. When the fiber is damaged, moisture in the environment is preferentially adsorbed by the collagen peptides. Dynamic moisture adsorption (DVS) tests show that, under 95% relative humidity, the equilibrium moisture absorption of the fiber of this invention reaches 83.69%, significantly higher than the 61.59% of PVA-boronic acid fiber without collagen peptides. Further analysis of the desorption curves reveals that the fiber of this invention exhibits a significant adsorption hysteresis phenomenon, and the residual water content is consistently higher than that of PVA-boronic acid fiber. This demonstrates that the complex hydrogen bond network constructed by the collagen peptides not only enhances the fiber's water absorption kinetics but also strengthens its ability to bind water molecules (water-locking effect) through intermolecular interactions.

[0030] The second stage: hydration and plasticization. The water captured by the collagen peptides forms a high-density water-bound layer at the fracture interface. The water-bound layer reduces the hydrogen bonding forces between PVA segments, increases the free volume, and lowers the activation energy for segment migration.

[0031] The third stage: interfacial diffusion. Under the action of hydration and plasticization, PVA molecular chains and collagen peptide molecular chains at the fracture interface diffuse rapidly and become entangled with each other.

[0032] Fourth stage: Dynamic bond recombination. The entangled molecular chains reconnect the dynamically cross-linked network of boronic esters distributed in the amorphous region, and the boronic ester bonds undergo exchange reactions: This forms a new cross-linked network, ultimately achieving efficient self-repair under normal temperature conditions.

[0033] After the introduction of collagen peptides, on the one hand, the crystallinity of PVA is reduced; on the other hand, a high-density bound water layer is formed. The bound water acts as a molecular lubricant, significantly reducing the activation energy of chain segment movement, interfacial diffusion resistance, and dynamic bond exchange energy barrier. This achieves a simultaneous improvement in both high strength and high repair efficiency.

[0034] Under the synergistic effect of the supramolecular interaction system and the hydration plasticization effect, the fiber of the present invention simultaneously achieves ultra-high mechanical strength and efficient self-healing triggered by room temperature water.

[0035] The second embodiment of the present invention provides a method for preparing high-strength self-healing polyvinyl alcohol fibers, comprising: Polyvinyl alcohol, collagen peptides and boric acid are uniformly mixed to obtain a spinning solution; The spinning solution is wet-spun and drawn, and then dried at 20~60℃.

[0036] The key to this implementation method is the use of low-temperature drying at 20~60℃. Within this temperature range, a reversible dynamic cross-linking network of borate esters is formed between boric acid and the hydroxyl groups of PVA and collagen peptides, rather than the permanent cross-linking obtained by high-temperature setting. Within this temperature range, the amorphous structure of collagen peptides is preserved, and its strong hydrophilic groups remain active, enabling it to exert subsequent hydration and plasticizing effects. If high-temperature setting is used, the borate ester bonds will be irreversibly solidified, the active hydrophilic groups of collagen peptides will be destroyed, and a homogeneous permanent cross-linked solidified body will be formed inside the fiber, completely losing its self-repairing ability.

[0037] The drawn fibers are then naturally dried or dried with hot air at 20–60°C for 0.5–24 hours. For example, they can be naturally dried at 25°C for 12 hours or dried with hot air at 40°C for 4 hours.

[0038] The preparation of the spinning solution is carried out using conventional techniques in this field, in which the raw materials are prepared into solutions and then mixed evenly.

[0039] The polyvinyl alcohol (PVA) solution is prepared by adding PVA to deionized water and heating under stirring to dissolve it. The solid-liquid mass ratio (PVA:water) is 1:3 to 1:6, preferably 1:4. The dissolution temperature is 85 to 98°C, and the dissolution time is 2 to 6 hours, preferably 4 hours at 95°C. The resulting PVA solution has a mass concentration of 14% to 25%. This suitable concentration range ensures that the spinning solution undergoes appropriate double diffusion in the coagulation bath, forming a dense and uniform nascent fiber structure. This provides a basis for molecular chain orientation and crystallization during the subsequent drawing process, thereby ensuring the tensile strength of the final fiber.

[0040] As an example, a method for preparing a collagen peptide solution involves adding collagen peptides to deionized water and stirring under mild conditions to dissolve them, thereby obtaining a collagen peptide solution. The solid-liquid mass ratio (collagen peptide:water) is 1:3 to 1:6, preferably 1:4. The dissolution temperature is 20 to 40°C, and the stirring time is 10 to 60 minutes, preferably 25°C for 30 minutes. The mass concentration of the resulting collagen peptide solution is 5% to 25%.

[0041] It is important to note that using a low temperature of 20-40℃ to dissolve collagen peptides, along with subsequent low-temperature drying, ensures that the collagen peptides remain in an amorphous state within the fibers, maintaining their hydration and plasticizing activity. If the temperature is too high during the initial dissolution or subsequent drying process, the active hydrophilic groups of the collagen peptides will be damaged, causing the fibers to lose their self-repairing ability.

[0042] The above polyvinyl alcohol solution, collagen peptide solution and boric acid (preferably 0.5%~5% by mass) are uniformly mixed in a predetermined ratio and then vacuum degassed to obtain a stable blend spinning solution.

[0043] As examples, the mixing temperature is 80~95℃ and the mixing time is 0.5~2 hours. This temperature range is adaptively adjusted according to the fluidity of the PVA solution and the stability of the collagen peptides. After mixing, vacuum degassing is used to eliminate air bubbles in the spinning solution. The vacuum degassing time is 0.5~2 hours to avoid filament breakage or defects during the spinning process.

[0044] The homogeneous spinning solution prepared above is extruded through a wet spinning machine and placed in a coagulation bath. Through double diffusion, the solvent and non-solvent exchange occurs, causing polymer precipitation to form nascent fibers. After being formed in the coagulation bath, the nascent fibers undergo stretching and drying.

[0045] Wet spinning is a conventional technique for preparing PVA fibers in this field. The spinning process parameters can be adjusted according to the fiber specifications and spinning equipment. For example, the spinning speed can be controlled between 0.3 and 3 L / h, preferably 1.5 L / h.

[0046] The coagulation bath uses a saturated sodium sulfate solution with a pH of 9-14, preferably 13; the coagulation bath temperature is 25-60℃, preferably 45℃. The alkaline environment (pH 9-14) facilitates the initial condensation of boric acid with the vicinal diol hydroxyl groups on the PVA and collagen peptide molecular chains, forming a borate ester pre-crosslinked structure. Simultaneously, the saturated sodium sulfate solution promotes rapid diffusion and precipitation of water from the spinning solution through osmotic pressure difference, causing the fiber to solidify and take shape.

[0047] The third embodiment of the present invention provides the application of high-strength self-healing polyvinyl alcohol fiber in the preparation of smart textiles, flexible electronic devices, biomedical dressings or wearable devices.

[0048] The high-strength self-healing polyvinyl alcohol fiber described in this invention possesses both ultra-high mechanical strength and self-healing capability triggered by room-temperature water. When applied to smart textiles, it can serve as a structural carrier fiber for flexible wires or sensors. In smart clothing or smart fabrics, after mechanical damage such as bending and abrasion, the fiber can self-repair through environmental moisture or sweat, restoring conductive pathways and structural integrity, thus extending the lifespan of the textile.

[0049] When applied to flexible electronic devices, it can serve as a substrate fiber for stretchable electrodes, flexible circuit boards, or wearable sensors. Microcracks generated during long-term repeated deformation of the device can be repaired by triggering repair with room temperature and humidity, improving the reliability and durability of the device under dynamic service conditions.

[0050] When applied to biomedical dressings, it can serve as a reinforcing fiber for high-strength absorbable sutures, tissue engineering scaffolds, or chronic wound dressings. After implantation in the human body, the fiber can trigger micro-damage repair through body fluids (high humidity environment); at the same time, both PVA and collagen peptides have good biocompatibility and are suitable for medical devices that come into long-term contact with human tissues.

[0051] When applied to wearable devices, it can be used as a structural fiber in components such as smartwatch straps, fitness tracker straps, and flexible battery encapsulation. During daily wear and washing, the fiber can self-repair through environmental moisture, maintaining the structural stability and wearing comfort of the device.

[0052] The preparation and properties of high-strength self-healing polyvinyl alcohol fiber are described in detail below through several examples.

[0053] The polyvinyl alcohol used in the following examples is PVA 26-99; the collagen peptides were obtained by hydrolysis of bovine hide and have a molecular weight of 10,000 Da.

[0054] In the following examples, "parts" refers to "parts by weight".

[0055] Example 1 63 parts of PVA were mixed and dissolved with deionized water at a solid-liquid mass ratio of 1:4 at 95°C to obtain a homogeneous PVA solution with a mass concentration of 25wt%. 35 portions of collagen peptides were mixed with deionized water at a solid-liquid mass ratio of 1:4 at 25°C to obtain a homogeneous collagen peptide solution with a mass concentration of 25 wt%. The PVA solution and collagen peptide solution obtained above were mixed evenly with 2 parts of boric acid at 95°C, and then vacuum degassing was performed for 1 hour to obtain a uniform spinning solution. Using wet spinning equipment, the above spinning solution is extruded through a spinneret into a coagulation bath at a spinneret speed of 1.5 L / h. The coagulation bath is a saturated sodium sulfate solution with a pH of 13 and a temperature of 45°C. After entering the coagulation bath, the spinning solution forms nascent fibers. After being stretched, the nascent fibers are naturally dried at 20°C to obtain high-strength self-healing polyvinyl alcohol fibers (PVA / Col-BA).

[0056] Comparative Example 1 The sample preparation method in Example 1 is the same as that in Example 1, except that collagen peptides were not added to the raw materials, and the collagen peptides were replaced with an equal amount of PVA. The raw materials by mass were 98 parts PVA and 2 parts boric acid.

[0057] Comparative Example 2 The sample preparation method is the same as in Example 1, except that the drying temperature is 230°C.

[0058] Comparative Example 3 The sample preparation method in Example 1 was the same, except that boric acid was not added to the raw materials, and the raw materials by mass were 63 parts PVA and 35 parts collagen peptides.

[0059] Comparative Example 4 The sample preparation method is the same as in Example 1, except that the raw materials, by mass, are: 48 parts PVA, 50 parts collagen peptides, and 2 parts boric acid.

[0060] Example 2 The sample preparation method is the same as in Example 1, except that the drying temperature is 60°C.

[0061] Example 3 The sample preparation method is the same as in Example 1, except that the raw materials, by mass, are: 93 parts PVA, 5 parts collagen peptides, and 2 parts boric acid.

[0062] Example 4 85 parts of PVA were mixed and dissolved with deionized water at a solid-liquid mass ratio of 1:4 at 90℃ to obtain a PVA solution with a mass concentration of 25 wt%. Ten parts of collagen peptides were mixed with deionized water at a solid-liquid mass ratio of 1:4 at 30℃ to obtain a collagen peptide solution with a mass concentration of 25 wt%. The PVA solution and collagen peptide solution obtained above were mixed with 1 part of boric acid at 90°C for 1 hour, and then vacuum degassed for 1 hour to obtain a uniform spinning solution. Using a wet spinning equipment, the above spinning solution is extruded through a spinneret into a coagulation bath at a spinneret speed of 5 L / h. The coagulation bath is a saturated sodium sulfate solution with a pH of 13 and a temperature of 45℃. After the spinning solution enters the coagulation bath, it forms nascent fibers. After being stretched, the nascent fibers are naturally dried at 20°C to obtain high-strength self-healing polyvinyl alcohol fibers.

[0063] Example 5 The raw materials, by weight, are 75 parts PVA, 20 parts collagen peptides, and 3 parts boric acid. The drying temperature is 40°C, and the rest of the preparation process is the same as in Example 3.

[0064] Example 6 The raw materials, by weight, are 55 parts PVA, 40 parts collagen peptides, and 5 parts boric acid. The drying temperature is 60°C, and the rest of the preparation process is the same as in Example 3.

[0065] Example 7 The raw materials, by weight, are 50 parts PVA, 45 parts collagen peptides, and 4 parts boric acid. The remaining preparation process is the same as in Example 3.

[0066] Example 8 The raw materials, by weight, are 95 parts PVA, 5 parts collagen peptides, and 3 parts boric acid. The remaining preparation process is the same as in Example 3.

[0067] The strength and toughness of the polyvinyl alcohol fiber samples prepared in the above embodiments and comparative examples were tested, and the strength self-healing rate was calculated. The results are shown in Table 1.

[0068] The fiber strength was evaluated using a YM06E electronic fiber strength tester (Electronic Instrument Ltd., Laizhou, China) according to GB / T 14337-2022 standard. Samples with a length of 2 cm, an elongation rate of 10 mm / min, and a pretension of 0.2 cN were tested. The experiments were conducted at room temperature and 65% relative humidity. The toughness value was obtained by calculating the integral area under the stress-strain curve.

[0069] To assess the healing effect, each fiber sample was cut into two pieces using a razor blade. With the two halves in contact, 10 ml of water was dripped onto the wound. Without applying any external force, the fibers self-healed for 24 hours. Subsequently, tensile tests (10 mm / min) were performed on the fibers before and after healing. The healing efficiency was determined by the ratio of the fracture stress before and after healing. Each experiment was repeated three times, and the average value was taken as the strength self-healing rate.

[0070] Table 1 .

[0071] Example 9 The fiber sample prepared in Example 1 was cut to prepare standard test strips. The cut strips were placed under the following four environmental conditions, all at a controlled temperature of 20°C, for 24 hours: 30% RH (low humidity environment), 60% RH (medium humidity environment), 95% RH (high humidity environment), and water immersion (fully wetted state), and were respectively numbered Group 1, Group 2, Group 3, and Group 4. The sample prepared in Comparative Example 1 was also prepared as a standard test strip and placed in a 95% RH (high humidity environment). After 24 hours, the strength self-healing rate of each group of samples was tested and calculated. The results are shown in Table 2.

[0072] Table 2 .

[0073] Comparative Example 8 The process parameters of Example 1 are the same, except that there is no boric acid crosslinking agent and no collagen peptides, and the raw material is 100 parts by mass of PVA.

[0074] Fourier transform infrared (FT-IR) spectroscopy was performed on the samples prepared in Example 1 (PVA / Col-BA), Comparative Example 1 (PVA-BA), and Comparative Example 8 (PVA). The specific method is as follows: Fourier transform infrared (FT-IR) spectra were recorded at room temperature using a Nicolet IS10 FT-IR spectrometer (ThermoFisher Scientific, USA) with a resolution of 4 cm⁻¹. -1 The range is 4000–400 cm. -1 .

[0075] Small-angle X-ray scattering (SAXS) was performed using a 5 Xeuss 2.0 system (Xenocs SA, France) equipped with a two-dimensional detector (600×600 pixels, pixel size: 172×172 μm²). Measurements were conducted using Cu Kα radiation (λ=1.54 Å). The sample-to-detector distance for SAXS was 539 mm. Fiber orientation was evaluated using orientation degree (π).

[0076] The dynamic moisture capture capacity of the fibers was assessed using a dynamic moisture adsorption tester (DVSIntrinsic, UK). The test humidity ranged from 0-95%RH, and the temperature was 25°C.

[0077] like Figure 1 As shown, in the spectrum of pure PVA fibers, 3432.96 cm⁻¹ -1 The broad peak at 2939 cm⁻¹ is attributed to the stretching vibration of -OH, while the peak at 2939 cm⁻¹ is attributed to the stretching vibration of -OH. -1 1462 cm -1 and 1090cm -1These correspond to CH stretching, -CH2- bending, and CO stretching vibrations, respectively. After the introduction of boric acid (PVA-BA), the -OH characteristic peak significantly red-shifted to 3264.63 cm⁻¹. -1 This indicates that a strong hydrogen bond network has been formed between boronic acid and the PVA chain. Meanwhile, at 1420 cm⁻¹... -1 With 1331cm -1 The newly emerging asymmetric tensile vibration peak corresponds to the BOC bond, confirming the tetrahedral coordination crosslinking structure formed by the hydroxyl group and the borate ion. For PVA / Col-BA fibers, the -OH peak further shifts to 3253.55 cm⁻¹. -1 This study revealed that the introduction of collagen peptides provided additional hydrogen bond donors for the system, enhancing the supramolecular interactions between the ternary components.

[0078] The micro-orientation degree of the fibers was quantitatively evaluated using small-angle X-ray scattering (SAXS), and the results are as follows: Figure 2 As shown in the figure. The study found that PVA-BA fibers exhibited the highest orientation factor, while the orientation factor (f) significantly decreased from 0.891 to 0.797 after the introduction of collagen peptides. Figure 2 As shown, the two-dimensional SAXS pattern of PVA / Col-BA fibers evolves from narrow stripes to diffuse rings, with increasingly blurred edge features. This phenomenon directly demonstrates that the intervention of amorphous collagen disrupts the long-range regularity of PVA molecular chains, resulting in a looser polymer network and reduced interchain entanglement. This transition from a highly oriented state to a random network state provides the necessary spatial tolerance for the free movement of chain segments at room temperature.

[0079] The moisture absorption and water retention properties of the fibers were quantitatively evaluated using dynamic moisture adsorption (DVS). Figure 3 As shown, the mass change of PVA / Col-BA and PVA-BA fibers is small in low humidity environments (RH < 60%); however, the adsorption capacity increases rapidly when the relative humidity exceeds 80%. At near-saturation at 95% RH, the equilibrium adsorption capacity of PVA / Col-BA fibers reaches 83.69%, far exceeding the 61.59% of PVA-BA fibers, confirming the significant contribution of biomass components to the hygroscopic performance.

[0080] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. High-strength self-healing polyvinyl alcohol fiber, characterized in that, The fiber is prepared by wet spinning and low-temperature drying from a spinning solution containing polyvinyl alcohol, collagen peptides, and boric acid. The fiber possesses a supramolecular interaction system, including: Crystallization-oriented polyvinyl alcohol phase; Collagen peptides dispersed in an amorphous state in the amorphous regions of the polyvinyl alcohol phase; and A dynamic cross-linked network of borate esters formed by boric acid, polyvinyl alcohol, and the hydroxyl groups of collagen peptides.

2. The high-strength self-healing polyvinyl alcohol fiber as described in claim 1, characterized in that, By weight, the polyvinyl alcohol comprises 50-95 parts, collagen peptides 5-45 parts, and boric acid 1-5 parts; the average molecular weight of the collagen peptides is 2000-10000 Da.

3. The high-strength self-healing polyvinyl alcohol fiber as described in claim 2, characterized in that, By weight, the composition is 63 parts polyvinyl alcohol, 35 parts collagen peptides, and 2 parts boric acid; the average molecular weight of the collagen peptides is 10,000 Da.

4. The high-strength self-healing polyvinyl alcohol fiber as described in claim 1, characterized in that, The temperature for the low-temperature drying is 20~60℃.

5. The method for preparing high-strength self-healing polyvinyl alcohol fiber as described in any one of claims 1-4, characterized in that, include: Polyvinyl alcohol, collagen peptides and boric acid are uniformly mixed to obtain a spinning solution; The spinning solution is wet-spun and drawn, and then dried at 20~60℃.

6. The preparation method according to claim 5, characterized in that, The spinning solution contains 14-25% polyvinyl alcohol, 5-25% collagen peptides, and 0.5-5% boric acid.

7. The preparation method according to claim 5, characterized in that, The coagulation bath for the wet spinning process is a saturated sodium sulfate solution with a pH of 9-14 and a temperature of 25-60℃.

8. The preparation method according to claim 5, characterized in that, The drying process is either natural drying or hot air drying, and the drying time is 0.5 to 24 hours.

9. The use of the high-strength self-healing polyvinyl alcohol fiber as described in any one of claims 1-4 in the preparation of smart textiles, flexible electronic devices, biomedical dressings or wearable devices.

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