Fiber material with high fatigue resistance, high response and high elasticity and preparation method thereof

Abstract

The invention provides a high-fatigue-resistance high-response high-elastic fiber material and a preparation method thereof. The high-fatigue-resistance high-response high-elastic fiber material comprises a liquid crystal functional phase, the high-fatigue-resistance high-response high-elastic fiber material further comprises a thermoplastic polymer elastic matrix phase, and the thermoplastic polymer elastic matrix phase and the liquid crystal functional phase construct a modulus smooth transition gradient layer on a two-phase interface through gradient coupling and topological interlocking. The modulus smooth transition gradient layer is used for efficiently transmitting strain and smoothly dissipating stress; wherein the weight-average molecular weight (Mw) of the thermoplastic polymer elastic matrix phase is 8.2 * 10 < 4 > g / mol to 2.5 * 10 < 5 > g / mol; by mass, the usage amount of the thermoplastic polymer elastic matrix phase is 50-90 parts. The fiber material with high fatigue resistance, high response and high elasticity has efficient stimulation responsiveness, high elasticity and toughness and excellent fatigue resistance, and is better adapted to dynamic application scenes such as intelligent fabrics, wearable equipment and flexible actuators.

Description

Technical Field

[0001] This disclosure relates to the field of fiber materials technology, and in particular to a high fatigue resistance, high response, and high elastic fiber material and its preparation method. Background Technology

[0002] Liquid crystal elastomers (LCEs), as a unique class of smart materials, can efficiently convert external stimuli (such as heat and light energy) into mechanical work, showing great application potential in fields such as flexible actuators, adaptive systems, and artificial muscles. Related academic research has successfully verified that LCE fibers can exhibit reversible contraction behavior under thermal stimulation and achieve high driven strain under specific conditions, thus realizing the environmental response of LCE fibers.

[0003] In dynamic applications such as smart fabrics, wearable devices, and flexible actuators, core requirements for fiber materials far exceed those for static demonstrations: they must possess high elasticity, high toughness, and fatigue resistance to withstand long-term cyclic loads. For example, patent CN121228384A discloses a smart responsive liquid crystal elastomer, specifically revealing that the outer layer of this patent's smart responsive liquid crystal elastomer is made of silicone, and the silicone is attached to the surface of the liquid crystal elastomer through an impregnation process. However, because the silicone and LCE are only bonded through simple intermolecular physical bonding, there is a problem of poor molecular interface bonding between the LCE and silicone. This results in the final LCE failing to simultaneously possess the inherent contradiction of high stimulus responsiveness and high elasticity and toughness at the molecular interface, often exhibiting high stimulus responsiveness but low elasticity and toughness. Furthermore, the low elasticity and toughness of highly responsive smart LCEs essentially lack the flexible chain segments and effective energy dissipation mechanisms required by elastomers, causing existing smart responsive liquid crystal elastomers to suffer from poor elasticity and toughness and insufficient fatigue resistance. Summary of the Invention

[0004] The purpose of this disclosure is to overcome the shortcomings of the prior art and provide a high fatigue-resistant, high-response, and high-elastic fiber material and its preparation method that simultaneously possesses high efficiency in stimulus responsiveness, high elasticity and toughness, and excellent fatigue resistance, so as to better adapt to dynamic application scenarios such as smart fabrics, wearable devices, and flexible actuators.

[0005] The purpose of this disclosure is achieved through the following technical solution: A high fatigue resistance, high response, and high elastic fiber material includes a liquid crystal functional phase and a thermoplastic polymer elastic matrix phase. The thermoplastic polymer elastic matrix phase and the liquid crystal functional phase form a modulus smooth transition gradient layer at the interface of the two phases through gradient coupling and topological interlocking. The modulus smooth transition gradient layer is used to efficiently transfer strain and smooth dissipate stress. The thermoplastic polymer elastic matrix phase contains active groups, which include at least one of acid anhydride, epoxy, carboxyl, hydroxyl, amine and unsaturated double bond; The weight-average molecular weight (M) of the thermoplastic polymer elastic matrix phase w The value is 8.2 × 10 4 g / mol - 2.5 × 10 5 g / mol; The amount of the thermoplastic polymer elastic matrix phase used is 50-90 parts by weight.

[0006] In one embodiment, the thermoplastic polymer elastic matrix phase includes at least one of styrene block copolymers, thermoplastic polyester elastomers, thermoplastic polyurethane elastomers, and dynamically vulcanized thermoplastic elastomers.

[0007] In one embodiment, the styrene-based block copolymer includes at least one of maleic anhydride-grafted styrene-butadiene-styrene block copolymer and epoxidized styrene-butadiene-styrene block copolymer; and / or, The thermoplastic polyester elastomer comprises at least one of polybutylene terephthalate-polytetrahydrofuran ether block copolymer and maleic anhydride-grafted thermoplastic polyester elastomer; and / or, The thermoplastic polyurethane elastomer includes at least one of polyester-type polyurethane elastomers and polyether-type polyurethane elastomers; and / or, The dynamically vulcanized thermoplastic elastomer includes a polypropylene / ethylene propylene diene monomer (EPDM) rubber blend vulcanization system.

[0008] In one embodiment, the high elasticity of the high fatigue resistance, high response, and high elastic fiber material refers to a breaking elongation of >300%; and / or, The high fatigue resistance of the high fatigue-resistant, high-response, and high-elastic fiber material refers to an elastic recovery rate of >85% at 50% strain; and / or, The high response of the high fatigue resistance, high response, and high elastic fiber material refers to the reversible response deformation of the high fatigue resistance, high response, and high elastic fiber material being 5%-50%, and the response cycle life of the high fatigue resistance, high response, and high elastic fiber material being >5000 cycles.

[0009] In one embodiment, the monofilament diameter of the high fatigue resistance, high response, and high elasticity fiber material is 50µm-1000µm.

[0010] In one embodiment, the amount of liquid crystal functional phase used is 10 to 50 parts by weight.

[0011] A method for preparing a high fatigue-resistant, high-response, and high-elastic fiber material includes the following steps: Liquid crystal monomers, chain extenders, catalysts, crosslinking agents and initiators are mixed to obtain a precursor solution A of the liquid crystal functional phase; A thermoplastic polymer elastic matrix and a solvent are mixed to obtain a precursor solution B of the thermoplastic polymer elastic matrix phase; The precursor solution A and the precursor solution B are subjected to intermittent ultrasonic treatment to obtain a mixture; wherein the conditions for the intermittent ultrasonic treatment are: power of 300W-500W, frequency of 20kHz-40kHz, and time of 30min-60min. The mixture was subjected to vacuum centrifugation and degassing followed by gradient desolventizing to obtain composite masterbatch C. The composite masterbatch C was subjected to hot melt extrusion in-situ crosslinking spinning treatment, and fiber samples were obtained after cooling. The fiber sample is subjected to a stretching process to obtain the high fatigue resistance, high response, and high elasticity fiber material described in any of the above embodiments.

[0012] In one embodiment, the conditions for the vacuum centrifugal degassing treatment are: vacuum degree of 80kPa-100kPa, rotation speed of 3000rpm-5000rpm, and time of 10min-20min.

[0013] In one embodiment, the gradient desolventizing process includes a first desolventizing stage and a second desolventizing stage, wherein the conditions for the first desolventizing stage are: a vacuum degree of 20 kPa-40 kPa and standing at room temperature for 4-6 hours. The conditions for the second solvent removal stage are: vacuum degree > 95 kPa, temperature 55℃-85℃ for 6h-12h.

[0014] In one embodiment, the temperature during the hot melt extrusion in-situ crosslinking spinning process is 160°C-200°C, and the screw speed during extrusion is controlled at 30 rpm-150 rpm; and / or, In the step of mixing the liquid crystal monomer, chain extender, catalyst, crosslinking agent, and initiator, a low-dimensional nanofiller is also added; and / or, The liquid crystal monomer includes at least one of the following: thermally responsive nematic liquid crystal monomer, chiral liquid crystal monomer, chiral doped liquid crystal monomer, photoresponsive liquid crystal monomer, ionic liquid crystal monomer, hydrogen-containing liquid crystal monomer, and siloxane liquid crystal monomer.

[0015] Compared with the prior art, this disclosure has at least the following advantages: 1) Due to the high elasticity of the thermoplastic polymer elastic matrix phase, the addition of the thermoplastic polymer elastic matrix phase can enhance the elasticity of the liquid crystal functional phase, thereby improving the deformation recovery rate and cycle stability of the high fatigue resistance, high response, and high elasticity fiber material. The active groups (such as acid anhydrides, epoxy, carboxyl, hydroxyl, amino groups, and unsaturated double bonds) of the thermoplastic polymer elastic matrix phase can react with the active groups (hydroxyl, amino) of the liquid crystal functional phase through nucleophilic ring-opening / addition reactions, free radical grafting reactions, or click chemistry reactions to form stable chemical covalent bonds, constituting the strongest first-level strong interaction. Subsequently, the thermoplastic polymer elastic matrix... During the in-situ crosslinking and spinning process of the thermoplastic polymer elastic matrix phase and the liquid crystal functional phase, driven by a high shear field, the long molecular chains of both phases diffuse and entangle into each other. This allows the molecular chains of the thermoplastic polymer elastic matrix phase to generate sufficient physical entanglement density at the bonding interface. The entangled molecular chains of the thermoplastic polymer elastic matrix phase encapsulate the rigid network of the liquid crystal functional phase, forming secondary interactions including hydrogen bonding and a large number of van der Waals forces. This constitutes a second- and third-level bonding force, which is relatively weak but has a wide range. This continuous distribution from the first-level strong covalent bonds to the subsequent multiple weak interactions can form a modulus smooth transition gradient layer in the bonding interface region. The first-level strong covalent bonds of the modulus smooth transition gradient layer act as the fulcrum for stress transmission, ensuring the efficient and forced transmission of the driving force of the liquid crystal functional phase to the thermoplastic polymer elastic matrix phase. Meanwhile, the modulus smooth transition gradient layer formed by the penetration of the long molecular chains of the thermoplastic polymer elastic matrix phase effectively suppresses the concentration of stress at the edge of the brittle liquid crystal functional phase and smoothly dissipates the fatigue energy under cyclic loading. Through this point-to-surface collaborative interface construction mechanism, it is ensured that the prepared high fatigue resistance, high response and high elasticity fiber material can simultaneously achieve high elasticity (provided by the flexible chain segments of the thermoplastic polymer elastic matrix phase and the modulus smooth transition gradient layer), cycle stability (the modulus smooth transition gradient layer eliminates stress concentration and inhibits crack initiation) and excellent environmental responsiveness (covalent bonds and topological interlocking ensure synchronous deformation).

[0016] 2) During the diffusion and entanglement of the thermoplastic polymer elastic matrix phase and the liquid crystal functional phase, the molecular chains of the two phases do not exist independently, but rather form a three-dimensional continuous interpenetrating network structure that interpenetrates and intertwines with each other. This structure geometrically constitutes "topological interlocking," allowing the flexible molecular chains of the thermoplastic polymer elastic matrix phase to pass through the "mesh" of the relatively rigid liquid crystal functional phase like "threads," and the chain segments of the liquid crystal functional phase are also embedded in the entangled clusters of the thermoplastic polymer elastic matrix phase. When the liquid crystal functional phase is stimulated to shrink, its molecular network size decreases. Due to topological interlocking, the molecular chains of the intertwined thermoplastic polymer elastic matrix phase are mechanically pulled and straightened, directly converting the nanoscale phase transition displacement of the liquid crystal functional phase into a synergistic stretching of a large number of thermoplastic polymer elastic matrix phases, thereby efficiently amplifying it into a macroscopically observable large strain (such as >20% shrinkage). This process involves direct energy transfer with minimal hysteresis and high response efficiency. When the stimulus is removed, the entropic elastic restoring force (contraction force) stored in the stretched thermoplastic polymer elastic matrix phase becomes the main driving force. Similarly, through the topological interlocking structure, this restoring force acts in reverse on the liquid crystal functional phase, helping its molecular chains overcome internal friction, coordinate and quickly reorient and align, and return to a state that can respond again. This achieves bidirectional dynamic coordination, endowing the high fatigue resistance, high response, and high elastic fiber material with excellent shape recovery rate and cycle stability.

[0017] 3) Gradient coupling and topological interlocking are not independent, but rather two complementary properties and functional manifestations of the same interface structure. Gradient coupling ensures the strength and static reliability of the modulus smooth transition gradient layer, which is the basis for the stable existence and long-term function of the topological interlocking structure. Topological interlocking, on the other hand, endows the modulus smooth transition gradient layer with the dynamic function of efficiently transferring strain and energy. Together, they determine that the high fatigue resistance, high response, and high elasticity fiber material has both high efficiency in stimulus response, high elasticity and toughness, and excellent fatigue resistance, making it better suited for dynamic application scenarios such as smart fabrics, wearable devices, and flexible actuators.

[0018] 4) If the weight-average molecular weight (M) of the added thermoplastic polymer elastic matrix phase is... w If the molecular weight is too large, too small, too much, or too little, the resulting modulus-smooth transition gradient layer will fail to efficiently transfer strain and smoothly dissipate stress. Therefore, in this disclosure, by further controlling the weight-average molecular weight (Mi) of the thermoplastic polymer elastic matrix phase... w The value is 8.2 × 10 4 g / mol - 2.5 × 10 5The amount of the thermoplastic polymer elastic matrix phase used is 50-90 parts per mol. This ensures that the added thermoplastic polymer elastic matrix phase can effectively wrap and encapsulate the liquid crystal functional phase, while also ensuring that the formed modulus smooth transition gradient layer can efficiently transfer strain and smoothly dissipate stress. This ensures that the prepared high fatigue resistance, high response, and high elasticity fiber material has both high stimulus responsiveness, high elasticity and toughness, and excellent fatigue resistance. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of this disclosure and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram illustrating the gradient coupling and topological interlocking of the thermoplastic polymer elastic matrix phase and the liquid crystal functional phase of the present invention. Figure 2 This is a characterization diagram of the tensile fracture properties of the high fatigue resistance, high response, and high elasticity fiber material of Embodiment 1 of the present invention; Figure 3 This is a characterization diagram of the tensile cycle performance of the high fatigue resistance, high response, and high elasticity fiber material of Embodiment 1 of the present invention; Figure 4 This is a comparison of the microstructure of the high fatigue resistance, high response, and high elastic fiber material of Embodiment 1 of the present invention before and after environmental stimulus response. Detailed Implementation

[0021] To facilitate understanding of this disclosure, a more complete description will be given below with reference to the accompanying drawings, which illustrate preferred embodiments of the present disclosure. However, this disclosure can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure.

[0022] It should be noted that when an element is referred to as being "fixed to" another element, it can be directly attached to the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0023] 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 disclosure belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of this disclosure. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0024] To better understand the technical solutions and beneficial effects of this disclosure, the following detailed description is provided in conjunction with specific embodiments: One embodiment of the high-fatigue-resistant, high-response, and high-elasticity fiber material includes a liquid crystal functional phase, which enables the liquid crystal functional phase to provide responsiveness to external stimuli (heat, light, etc.). Upon stimulation, the liquid crystal functional phase undergoes a reversible phase transition and deformation to achieve the responsive performance of the high-fatigue-resistant, high-response, and high-elasticity fiber material. The high-fatigue-resistant, high-response, and high-elasticity fiber material also includes a thermoplastic polymer elastic matrix phase, which allows the added thermoplastic polymer elastic matrix phase to form a continuous mechanical skeleton, improving the overall high elasticity, high elongation at break, and processability of the material. The thermoplastic polymer elastic matrix phase and the liquid crystal functional phase construct a modulus smooth transition gradient layer at the two-phase interface through gradient coupling and topological interlocking. This modulus smooth transition gradient layer is used to efficiently transfer strain and smoothly dissipate stress.

[0025] It is understandable that the high elasticity of the thermoplastic polymer elastic matrix phase ensures that the added thermoplastic polymer elastic matrix phase can improve the elasticity of the liquid crystal functional phase, thereby enhancing the deformation recovery rate and cycle stability of the high fatigue resistance, high response, and high elasticity fiber material. Furthermore, the active groups (such as acid anhydrides, epoxy groups, carboxyl groups, hydroxyl groups, amino groups, and unsaturated double bonds) of the thermoplastic polymer elastic matrix phase can react with the active groups (hydroxyl and amino groups) of the liquid crystal functional phase, such as nucleophilic ring-opening / addition reactions, free radical grafting reactions, or click chemistry reactions, to form stable chemical covalent bonds, constituting the strongest binding force. The first level is strong interaction; subsequently, driven by the high shear field during the in-situ crosslinking and spinning process of the thermoplastic polymer elastic matrix phase and the liquid crystal functional phase through hot melt extrusion, the long molecular chain segments of the two phases diffuse and entangle into each other's phases. This allows the molecular chains of the thermoplastic polymer elastic matrix phase to generate sufficient physical entanglement density at the bonding interface region. The entangled molecular chains of the thermoplastic polymer elastic matrix phase encapsulate the rigid liquid crystal functional phase network, forming secondary interactions including hydrogen bonding forces and a large number of van der Waals forces. These constitute the second and third level of bonding forces, which are weaker but have a wider range. Please refer to [link to relevant documentation]. Figure 1This continuous distribution from the first-level strong covalent bonds to subsequent weak interactions forms a modulus smooth transition gradient layer in the bonding interface region. The first-level strong covalent bonds of the modulus smooth transition gradient layer act as the fulcrum for stress transfer, ensuring the efficient and forced transfer of the driving force of the liquid crystal functional phase to the thermoplastic polymer elastic matrix phase. Meanwhile, the modulus smooth transition gradient layer formed by the infiltration of long molecular chains of the thermoplastic polymer elastic matrix phase effectively suppresses stress concentration at the edge of the brittle liquid crystal functional phase, smoothly dissipating fatigue energy under cyclic loading. Through this point-to-surface synergistic interface construction mechanism, it is ensured that the prepared high-fatigue-resistant, high-response, and high-elasticity fiber material can simultaneously achieve high elasticity (provided by the flexible chain segments of the thermoplastic polymer elastic matrix phase and the modulus smooth transition gradient layer), cyclic stability (the modulus smooth transition gradient layer eliminates stress concentration and inhibits crack initiation), and excellent environmental responsiveness (covalent bonds and topological interlocking ensure synchronous deformation).

[0026] It can also be understood that during the diffusion and entanglement of the thermoplastic polymer elastic matrix phase and the liquid crystal functional phase, the molecular chains of the two phases do not exist independently, but rather form a three-dimensional continuous interpenetrating network structure that interpenetrates and intertwines with each other. This structure geometrically constitutes "topological interlocking," allowing the flexible molecular chains of the thermoplastic polymer elastic matrix phase to pass through the "mesh" of the relatively rigid liquid crystal functional phase like "threads," and the chain segments of the liquid crystal functional phase are also embedded in the entangled clusters of the thermoplastic polymer elastic matrix phase; when the liquid crystal functional phase is stimulated to shrink, its molecular network size decreases. Due to topological interlocking, the molecular chains of the intertwined thermoplastic polymer elastic matrix phase are mechanically pulled and straightened, so as to directly convert the nanoscale phase transition displacement of the liquid crystal functional phase into a synergistic stretching of a large number of thermoplastic polymer elastic matrix phases, thereby efficiently amplifying it into a macroscopically observable large strain (such as >20% shrinkage). This process involves direct energy transfer with minimal hysteresis and high response efficiency. When the stimulus is removed, the entropic elastic restoring force (contraction force) stored in the stretched thermoplastic polymer elastic matrix phase becomes the main driving force. Similarly, through the topological interlocking structure, this restoring force acts in reverse on the liquid crystal functional phase, helping its molecular chains overcome internal friction, coordinate and quickly reorient and align, and return to a state that can respond again. This achieves bidirectional dynamic coordination, endowing the high fatigue resistance, high response, and high elastic fiber material with excellent shape recovery rate and cycle stability.

[0027] It can also be understood that gradient coupling and topological interlocking are not independent, but rather two complementary properties and functional manifestations of the same interface structure. Gradient coupling ensures the toughness and static reliability of the modulus smooth transition gradient layer, which is the basis for the stable existence and long-term function of the topological interlocking structure. Topological interlocking, on the other hand, endows the modulus smooth transition gradient layer with the dynamic function of efficiently transferring strain and energy. Together, they determine that the high fatigue resistance, high response, and high elasticity fiber material has both high efficiency in stimulus response, high elasticity and toughness, and excellent fatigue resistance, making it better suited for dynamic application scenarios such as smart fabrics, wearable devices, and flexible actuators.

[0028] It should be noted that, since thermoplastic polymer elastic matrix phases are common materials for enhancing flexibility, such as the thermoplastic polyester elastomer composition disclosed in patent CN106459566A, some researchers have attempted to introduce this thermoplastic polyester elastomer composition (CN106459566A) into liquid crystal elastomers. Specifically, they have introduced the polyester of the modified hydrogenated styrene-based elastomer (with a number-average molecular weight of 30,000–80,000) into the liquid crystal functional phase. However, the molecular weight of this patented thermoplastic polyester elastomer composition is relatively small, making it difficult to effectively wrap around and encapsulate the liquid crystal functional phase. Therefore, this disclosure further optimizes the molecular chain and amount of the plastic polymer elastic matrix phase.

[0029] Furthermore, if the weight-average molecular weight (M) of the added thermoplastic polymer elastic matrix phase is high... w If the molecular weight is too large, too small, or the amount used is excessive or insufficient, the resulting modulus-smooth transition gradient layer will fail to efficiently transfer strain and smoothly dissipate stress. Therefore, in this disclosure, by further controlling the weight-average molecular weight (Mi) of the thermoplastic polymer elastic matrix phase... w The value is 8.2 × 10 4 g / mol - 2.5 × 10 5 The amount of g / mol and the thermoplastic polymer elastic matrix phase used is 50-90 parts. This ensures that the added thermoplastic polymer elastic matrix phase can effectively wrap and encapsulate the liquid crystal functional phase, while also ensuring that the formed modulus smooth transition gradient layer can efficiently transfer strain and smoothly dissipate stress. This ensures that the prepared high-fatigue-resistant, high-responsive, and high-elasticity fiber material possesses both high stimulus responsiveness, high elasticity and toughness, and excellent fatigue resistance. For details, please refer to [reference needed]. Figures 2 to 4 .

[0030] Specifically, from Figure 2As can be seen, this discloses the tensile fracture performance characterization curve of the high fatigue resistance, high response, and high elasticity fiber material. This figure shows the stress-strain relationship of the fiber material during the tensile process, reflecting that the material has extremely high elongation at break (e.g., exceeding 1600%) and excellent mechanical toughness, demonstrating the supporting role of the thermoplastic polymer matrix as a mechanical skeleton.

[0031] from Figure 3 As can be seen, the performance of the high fatigue resistance, high response, and high elasticity fiber material disclosed in this invention was characterized during multiple tensile cycles. This figure shows the stress-strain hysteresis loop distribution of the fiber material under cyclic loading; the high degree of overlap of the multiple cycle curves demonstrates that the material possesses excellent elastic recovery and superior fatigue resistance reliability.

[0032] from Figure 4 As can be seen, the microstructure comparison images of the high fatigue resistance, high response, and high elasticity fiber material disclosed in this paper before and after environmental stimulus response are shown. The left image (before response) shows the straight morphology of the fiber in its original state, with a smooth surface and dense structure. The right image (after response) visually demonstrates the obvious axial shrinkage deformation of the fiber after stimulation. The scale bar in the figures clearly quantifies the microscopic size of the fiber and its structural integrity during large-scale deformation, confirming the effective transmission of driving strain by the gradient coupling interface.

[0033] In one embodiment, the thermoplastic polymer elastic matrix phase includes at least one of styrene block copolymers, thermoplastic polyester elastomers, thermoplastic polyurethane elastomers, and dynamically vulcanized thermoplastic elastomers.

[0034] In one embodiment, the styrene-based block copolymer includes at least one of maleic anhydride-grafted styrene-butadiene-styrene block copolymer and epoxidized styrene-butadiene-styrene block copolymer, wherein the maleic anhydride-grafted styrene-butadiene-styrene block copolymer and the epoxidized styrene-butadiene-styrene block copolymer undergo a free radical grafting reaction with the liquid crystal functional phase to achieve gradient coupling and topological interlocking between the two phases.

[0035] In one embodiment, the thermoplastic polyester elastomer includes at least one of polybutylene terephthalate-polytetrahydrofuran ether block copolymer and maleic anhydride-grafted thermoplastic polyester elastomer to achieve gradient coupling and topological interlocking between the two phases.

[0036] In one embodiment, the thermoplastic polyurethane elastomer includes at least one of polyester-type polyurethane elastomer and polyether-type polyurethane elastomer to achieve gradient coupling and topological interlocking between the two phases.

[0037] In one embodiment, the dynamically vulcanized thermoplastic elastomer comprises a polypropylene / ethylene propylene diene monomer (EPDM) rubber blend vulcanization system to achieve gradient coupling and topological interlocking between the two phases.

[0038] In one embodiment, the high elasticity of the high fatigue resistance, high response, and high elastic fiber material obtained by compounding 50-90 parts of a plastic polymer elastic matrix phase with 10-50 parts of a liquid crystal functional phase refers to the elongation at break of the high fatigue resistance, high response, and high elastic fiber material being >300%; the high fatigue resistance of the high fatigue resistance, high response, and high elastic fiber material refers to the elastic recovery rate of the high fatigue resistance, high response, and high elastic fiber material being >85% at 50% strain; and the high response of the high fatigue resistance, high response, and high elastic fiber material refers to the reversible response deformation of the high fatigue resistance, high response, and high elastic fiber material being 5%-50%, thereby ensuring that the prepared high fatigue resistance, high response, and high elastic fiber material simultaneously possesses high efficiency in stimulus response, high elasticity and toughness, and excellent fatigue resistance.

[0039] In one embodiment, the elongation at break of the high fatigue resistance, high response, and high elastic fiber material is 600%-1800%.

[0040] In one embodiment, the monofilament diameter of the high fatigue resistance, high response, and high elasticity fiber material is 50µm-1000µm.

[0041] It should be noted that current traditional methods for preparing smart responsive liquid crystal elastomers typically require templates, which presents a complexity in the process. Furthermore, the presence of templates restricts the free orientation of liquid crystal monomers, resulting in low orientation of the multi-domain liquid crystal elastomer fibers formed after cross-linking. This leads to limitations in response sensitivity and deformation, hindering their suitability for dynamic applications such as smart fabrics, wearable devices, and flexible actuators.

[0042] Therefore, this disclosure also provides a method for preparing a high-fatigue-resistant, high-response, and high-elastic fiber material. First, a liquid crystal monomer, a chain extender, a catalyst, a crosslinking agent, and an initiator are mixed to obtain a precursor solution A of the liquid crystal functional phase. Next, a thermoplastic polymer elastic matrix and a solvent are mixed to obtain a precursor solution B of the thermoplastic polymer elastic matrix phase. Subsequently, the precursor solution A and the precursor solution B are subjected to intermittent ultrasonic treatment to obtain a mixture. The conditions for the intermittent ultrasonic treatment are: power of 300W-500W, frequency of 20kHz-40kHz, and time of 30min-60min. Immediately afterwards, the mixture is subjected to vacuum centrifugation degassing and gradient desolventizing treatment to obtain a composite masterbatch C. Then, the composite masterbatch C is subjected to hot melt extrusion in-situ crosslinking spinning treatment, and after cooling, a fiber sample is obtained. Finally, the fiber sample is subjected to stretching treatment to obtain a high-fatigue-resistant, high-response, and high-elastic fiber material.

[0043] The above-mentioned method for preparing high fatigue resistance, high response, and high elasticity fiber materials does not require an auxiliary template, thus effectively simplifying the preparation steps. Furthermore, the shear force field of the hot melt extrusion in-situ crosslinking spinning process can precisely induce the orderly orientation of the liquid crystal monomer units along the fiber axis, allowing the high response characteristics of the liquid crystal monomers to be fully utilized. At the same time, the shear force field of the hot melt extrusion in-situ crosslinking spinning process also causes the long molecular chain segments of the two phases to diffuse and entangle into each other to form a modulus smooth transition gradient layer. This ensures that the prepared high fatigue resistance, high response, and high elasticity fiber materials simultaneously possess high efficiency in stimulus response, high elasticity and toughness, and excellent fatigue resistance, making them better suited for applications in dynamic scenarios such as smart fabrics, wearable devices, and flexible actuators.

[0044] One embodiment of a high fatigue resistance, high response, and high elasticity fiber material includes some or all of the following steps: S101. Mix the liquid crystal monomer, chain extender, catalyst, crosslinking agent and initiator to obtain a precursor solution A of the liquid crystal functional phase.

[0045] It is understandable that the added liquid crystal monomers provide the foundation for the subsequent formation of responsive liquid crystal building blocks. Chain extenders can lengthen molecular chains, which is beneficial for constructing a three-dimensional continuous interpenetrating network structure that is interconnected and interwoven. Furthermore, chain extenders can adjust the molecular chain length and initial modulus of the precursor solution A of the liquid crystal functional phase, reducing the modulus difference between it and the precursor solution B of the thermoplastic polymer elastic matrix phase, thus providing a modulus-matching basis for constructing a smooth modulus transition layer. By uniformly premixing the liquid crystal monomers, chain extenders, catalysts, crosslinking agents, and initiators to obtain a uniform and stable precursor solution A of the liquid crystal functional phase, a uniform modulus-smooth transition gradient layer can be prepared, avoiding the problem of local modulus abrupt changes in the smooth modulus transition gradient layer.

[0046] It is also understandable that, since liquid crystal monomers, chain extenders, and crosslinking agents are mostly small molecules or oligomers, they have good compatibility and can be premixed uniformly without the aid of solvents. This avoids the interaction between the solvent and the structural units of the liquid crystal monomers (such as cyanobiphenyl and cyclohexane-benzene ring rigid skeletons), preventing the destruction of the ordered structure of the liquid crystal monomer units and preserving their ability to form an oriented liquid crystal network. This ensures that the high fatigue resistance, high response, and high elasticity fiber material prepared in the end has high responsiveness. It also avoids the solvent from prematurely initiating the reaction of the crosslinking agent and initiator, preventing local crosslinking and solidification of the liquid crystal functional phase during the mixing stage. This ensures that the liquid crystal monomers can be uniformly dispersed in a flowable precursor state, guaranteeing uniform mixing with the precursor solution B of the thermoplastic polymer elastic matrix phase.

[0047] In one embodiment, the liquid crystal monomer includes at least one of thermally responsive nematic liquid crystal monomers, chiral liquid crystal monomers, chiral doped liquid crystal monomers, photoresponsive liquid crystal monomers, ionic liquid crystal monomers, hydrogen-containing liquid crystal monomers, and siloxane liquid crystal monomers.

[0048] In one embodiment, the thermally responsive nematic liquid crystal monomer includes at least one of (meth)acrylate monomers, cyanobiphenyl monomers, terphenyl monomers, cyclohexane-phenyl ring monomers, and biphenyl ring rigid framework monomers.

[0049] In one embodiment, the (meth)acrylate monomers include at least one of RM23, RM105, RM149, RM257, RM84, RM82, RM2, RM111, C6M, and C12M.

[0050] In one embodiment, the cyanobiphenyl monomer includes at least one of 5CB and 8CB.

[0051] In one embodiment, the cyanotriphenyl monomer includes 7CT.

[0052] In one embodiment, the cyclohexane-phenyl ring monomer includes LC104.

[0053] In one embodiment, the biphenyl ring rigid framework monomer includes LC242.

[0054] In one embodiment, the chiral liquid crystal monomer includes at least one of LC756 and MLC-204.

[0055] In one embodiment, the photoresponsive liquid crystal monomer includes at least one of azobenzene monomers, cinnamate monomers, anthracene or diarylethylene monomers, and spiropyran / oxazine monomers.

[0056] In one embodiment, the chain extender comprises at least one selected from a difunctional thiol compound, a difunctional diacrylate compound, and a difunctional diisocyanate compound. Further, difunctionality refers to a functionality of 2.

[0057] In one embodiment, the bifunctional thiol compound includes at least one of 1,8-octanedithiol, 1,6-hexanedithiol, and 1,4-butanedithiol.

[0058] In one embodiment, the bifunctional diacrylate compound includes at least one selected from ethylene glycol di(3-mercaptopropionate) (EGDMP), polyethylene glycol di(3-mercaptopropionate), 1,4-butanediol diacrylate (BDDA), 1,6-hexanediol diacrylate (HDDA), polyethylene glycol diacrylate (PEGDA), and tripropylene glycol diacrylate (TPGDA).

[0059] In one embodiment, the bifunctional diisocyanate compound includes at least one of isophorone diisocyanate (IPDI) and hexamethylene diisocyanate (HDI).

[0060] In one embodiment, the catalyst includes at least one of triethylamine (TEA), N,N-diisopropylethylamine (DIPEA), di-n-propylamine (DPA), 1,8-diazabicycloundec-7-ene (DBU), 4-dimethylaminopyridine (DMAP), dibutyltin dilaurate (DBTDL), stannous octoate (Sn(Oct)2), cobalt naphthenate, iron acetylacetone, phosphoric acid, and p-toluenesulfonic acid.

[0061] In one embodiment, the crosslinking agent includes at least one of a multifunctional thiol compound and a multifunctional acrylate compound. Further, multifunctionality refers to a functionality ≥3.

[0062] In one embodiment, the multifunctional acrylate compound includes at least one of trimethylolpropane tris(3-mercaptopropionate) (TMPMP), tris[(3-mercaptopropionyloxy)-ethyl]-isocyanurate (TEMIC), pentaerythritol tetraacrylate (PETA), trimethylolpropane triacrylate (TMPTA), dipentaerythritol penta / hexaacrylate (DPEPA), ethoxylated trimethylolpropane triacrylate, and triallyl isocyanurate (TAIC).

[0063] In one embodiment, the initiator includes benzoyl peroxide (BPO), dicumyl peroxide (DCP), azobisisobutyronitrile (AIBN), azobisisoheptanenitrile (ABVN), lauroyl peroxide (LPO), potassium persulfate (KPS), ammonium persulfate (APS), 2,2'-azobis(2-methylpropanediamine) dihydrochloride (V-50), di(2-ethylhexyl) percarbonate (EHP), tert-butyl hydroperoxide (TBHP); 2-hydroxy At least one of 2-methyl-1-phenyl-1-propanone (1173), 1-hydroxycyclohexylphenyl ketone (184), 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone (369), phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide (819), 2,2-dimethoxy-2-phenylacetophenone (651), benzoin dimethyl ether (651) and 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (TPO).

[0064] In one embodiment, during the step of mixing the liquid crystal monomer, chain extender, catalyst, crosslinking agent and initiator, a low-dimensional nanofiller is also added to enhance the flexibility of the modulus smooth transition gradient layer. This facilitates the construction of a continuous modulus gradient transition from the liquid crystal phase (high modulus) to the nanofiller (medium modulus) to the thermoplastic polymer elastic matrix phase (low modulus), thereby ensuring the formation of a suitable modulus smooth transition gradient layer.

[0065] In one embodiment, the amount of low-dimensional nanofiller used is 0.1 to 2 parts by weight.

[0066] In one embodiment, the low-dimensional nanofiller includes at least one of carbon nanotubes (CNTs), carbon black, graphene, and gold nanoparticles.

[0067] In one embodiment, the carbon nanotubes are carboxylated multi-walled carbon nanotubes. By introducing carboxyl active groups into the multi-walled carbon nanotubes, the compatibility of the carboxylated multi-walled carbon nanotubes with liquid crystal monomers, thermoplastic polymer elastic matrices, chain extenders, catalysts, crosslinking agents, and initiators is improved. This facilitates the preparation of a homogeneous and stable precursor solution A of the liquid crystal functional phase with numerous active groups, ensuring that the carboxylated multi-walled carbon nanotubes can effectively bridge the liquid crystal functional phase and the thermoplastic polymer elastic matrix phase. This, in turn, is beneficial for preparing a high-flexibility, high-modulus, smooth-transition gradient layer. Furthermore, the added carbon nanotubes possess high conductivity, thereby improving the responsiveness of the high-fatigue-resistant, high-response, and high-elasticity fiber material, making it better suited for dynamic applications such as smart fabrics, wearable devices, and flexible actuators.

[0068] In one embodiment, the step of mixing the liquid crystal monomer, chain extender, catalyst, crosslinking agent, initiator, and low-dimensional nanofiller includes the following specific steps: placing the liquid crystal monomer, chain extender, catalyst, crosslinking agent, initiator, and low-dimensional nanofiller in a specific temperature field formed by a constant temperature water bath or oil bath at 75℃-85℃ in a light-protected environment, first using magnetic stirring (300rpm-600rpm) for initial mixing for 1h to ensure preliminary compatibility of the components; then switching to mechanical stirring (800rpm-1200rpm) for high-speed stirring for 2h-4h to obtain a precursor solution A for preparing a uniform and stable liquid crystal functional phase.

[0069] In one embodiment, the precursor solution A of the liquid crystal functional phase comprises, by mass parts, 15-20 parts of liquid crystal monomer, 2-5 parts of chain extender, 0.1-2 parts of catalyst, 0.5-2 parts of crosslinking agent, 0.1-1.5 parts of initiator and 0.1-2 parts of low-dimensional nanofiller.

[0070] S102. The thermoplastic polymer elastic matrix and solvent are mixed to obtain a precursor solution B of the thermoplastic polymer elastic matrix phase.

[0071] It should be noted that in current methods for preparing smart responsive liquid crystal elastomers, such as those disclosed in patent CN 121228384A, liquid crystal monomers, crosslinking agents, photoinitiators, and catalysts are typically added to an organic solvent and stirred to dissolve, resulting in a mixed solution. This mixed solution is then injected into a template for the first crosslinking. After the solution crosslinks into fibers, the fibers are removed from the template, dried, and a multi-domain liquid crystal elastomer fiber, denoted as P-LCE fiber, is obtained. The obtained P-LCE fiber is then stretched and impregnated in a silica gel solution. The impregnated P-LCE fiber is then removed and suspended to allow the silica gel solution coating the fiber surface to dry and solidify before a second crosslinking process is performed to obtain the smart responsive liquid crystal elastomer. It is evident that the traditional approach involves first mixing the organic solvent with the liquid crystal monomer. If this disclosure directly employs the traditional preparation method, the thermoplastic polymer elastic matrix phase will exhibit a solvent-free state. The molecular chains of the solvent-free thermoplastic polymer elastic matrix phase are in a tangled and aggregated state. If directly mixed with the liquid crystal functional phase, the liquid crystal functional phase will be locally entrained and aggregated. Furthermore, the weight-average molecular weight (Mw) of the thermoplastic polymer elastic matrix phase used in this disclosure is 8.2 × 10⁻⁶. 4 g / mol - 2.5 × 10 5 The relatively large g / mol ratio results in relatively long molecular chains, which makes the problem of liquid crystal phase monomers being trapped and aggregated more pronounced, making it impossible to prepare a suitable modulus smooth transition gradient layer.

[0072] Therefore, in this disclosure, the solvent and the thermoplastic polymer elastic matrix are grouped together, so that the added solvent can fully wet and swell the thermoplastic polymer elastic matrix, allowing its molecular chains to fully extend and form a continuous and uniform fluid phase. On the one hand, this provides a stable carrier framework for the subsequent encapsulation and dispersion of the liquid crystal functional phase, effectively preventing particle agglomeration and local liquid crystal phase monomers from being trapped and aggregated during the mixing process, thus ensuring the uniformity of the two-phase dispersion from the source. On the other hand, it also ensures that the organic solvent can be thoroughly removed from the thermoplastic polymer elastic matrix during the subsequent gradient solvent removal process, effectively avoiding the problem that the liquid crystal monomers are squeezed and aggregated during the gradient solvent removal process, making it impossible to prepare a suitable gradient layer with a smooth modulus transition.

[0073] It is also understandable that the flexible molecular chains of the thermoplastic polymer elastic matrix are more flexible and more likely to form transition regions with molecular entanglement, hydrogen bonding, or van der Waals forces at the interface between the two phases, rather than simple physical contact. This greatly enhances the interfacial bonding force between the two phases, which is conducive to building a uniform and suitable modulus smooth transition gradient layer. This ensures that stress can be uniformly transmitted inside the high fatigue resistance, high response, and high elasticity fiber material, effectively avoiding the problem of stress not being uniformly transmitted inside due to the appearance of locally sharp or narrow modulus smooth transition gradient layers at the interface between the two phases.

[0074] In one embodiment, the solvent includes at least one of chloroform, N,N-dimethylformamide (DMF), tetrahydrofuran (THF), dichloromethane (DCM), dimethyl sulfoxide (DMSO), N-methylpyrrolidone (NMP), γ-butyrolactone (GBL), ethyl acetate, acetone, toluene, benzene, xylene (ortho, meta, para), mesitylene, anisole, and carbon tetrachloride.

[0075] In one embodiment, the mass ratio of solvent to thermoplastic polymer elastic matrix is ​​60-80 parts: 20-40 parts, to ensure that the added solvent can fully wet and swell the thermoplastic polymer elastic matrix, thereby ensuring that the molecular chains of the thermoplastic polymer elastic matrix are fully extended and form a continuous and uniform fluid phase.

[0076] In one embodiment, the thermoplastic polymer elastic matrix and solvent are mixed by mechanical stirring (500 rpm-700 rpm) for 1 h-2 h to obtain a homogeneous and stable precursor solution B of the thermoplastic polymer elastic matrix phase.

[0077] S103. The precursor solution A and the precursor solution B are subjected to intermittent ultrasonic treatment to obtain a mixture. It is understood that continuous ultrasonic treatment can lead to excessively high local temperatures, causing the initiator to react prematurely, thus preventing the preparation of a suitable modulus smooth transition gradient layer. Therefore, in this disclosure, intermittent ultrasonic treatment effectively avoids the problem of excessively high local temperatures caused by continuous ultrasonication, preventing premature initiator reaction. Furthermore, the cavitation effect generated by intermittent ultrasonic treatment can break the interface between the two phases, allowing the liquid crystal functional phase to be uniformly dispersed at the micro-nano scale in the thermoplastic polymer elastic matrix phase, preventing phase separation. This ensures that a suitable modulus smooth transition gradient layer can be constructed at the interface between the two phases, guaranteeing the preparation of a highly uniform, fatigue-resistant, highly responsive, and highly elastic fiber material.

[0078] In one embodiment, the conditions for the interval ultrasonic treatment are: power of 300W-500W, frequency of 20kHz-40kHz, and time of 30min-60min, to achieve interval ultrasonic treatment of precursor solution A and precursor solution B.

[0079] In one embodiment, the step of intermittently ultrasonically treating the precursor solution A and the precursor solution B includes the following specific steps: intermittently ultrasonically treating with a high-power probe (power 300W-500W, frequency 20kHz-40kHz) for 30min-60min, using ultrasonic cavitation to break up the aggregates of carboxylated multi-walled carbon nanotubes and liquid crystal monomer microregions, so that the liquid crystal functional phase is uniformly dispersed in the thermoplastic polymer elastic matrix phase, which is beneficial to constructing a suitable modulus smooth transition gradient layer.

[0080] S103. The mixture is subjected to vacuum centrifugation degassing and gradient desolventizing treatment in sequence to effectively remove bubbles and solvents from the mixture, while also improving the uniformity of the two-phase mixing, so as to obtain a highly compatible, bubble-free and microstructure-uniform composite masterbatch C.

[0081] In one embodiment, the vacuum centrifugation degassing treatment conditions are: vacuum degree of 80kPa-100kPa, rotation speed of 3000rpm-5000rpm, and time of 10min-20min. On the one hand, this can improve the uniformity of the mixture dispersion, and on the other hand, it can better remove the bubbles in the liquid dispersion. This is beneficial to the preparation of high fatigue resistance, high response, and high elasticity fiber materials that simultaneously possess high efficiency in stimulus response, high elasticity and toughness, and excellent fatigue resistance.

[0082] In one embodiment, the gradient desolventizing process includes a first desolventizing stage and a second desolventizing stage. The conditions for the first desolventizing stage are: a vacuum degree of 20 kPa-40 kPa and standing at room temperature for 4-6 hours, allowing a large amount of solvent to evaporate slowly and steadily, effectively preventing violent boiling and the generation of more voids, thereby ensuring that the two phases maintain a uniform dispersion state during the desolventizing process, which is conducive to the formation of a structurally stable composite masterbatch C, and effectively avoiding the problem of severe shrinkage of the thermoplastic polymer elastic matrix phase and aggregation of the liquid crystal functional phase caused by rapid solvent removal. The conditions for the second desolventizing stage are: a vacuum degree >95 kPa and a temperature of 55℃-85℃ for 6-12 hours, to completely remove residual solvent, so as to obtain a composite masterbatch C with highly compatible components, no bubbles and uniform microstructure.

[0083] In one embodiment, the mixture undergoes vacuum centrifugation degassing and gradient desolventizing treatment sequentially, including the following specific steps: the mixture is transferred to a high-speed centrifuge / vacuum degassing integrated device and pretreated at a speed of 3000rpm-5000rpm for 10min-20min; then the mixture after vacuum centrifugation degassing is placed in a vacuum drying oven for the first desolventizing stage (vacuum degree of 20kPa-40kPa, standing at room temperature for 4h-6h), then the vacuum degree is increased to above 95kPa, and the temperature is simultaneously raised to 55℃-85℃ for 6h-12h to complete the second desolventizing stage.

[0084] S104. The composite masterbatch C is subjected to hot melt extrusion in-situ crosslinking spinning treatment, and fiber samples are obtained after cooling.

[0085] It is understandable that hot melt extrusion in-situ crosslinking spinning treatment enables liquid crystal monomers to undergo in-situ crosslinking reactions within the thermoplastic polymer matrix. This allows the active groups (such as acid anhydrides, epoxy groups, carboxyl groups, hydroxyl groups, amino groups, and unsaturated double bonds) of the thermoplastic polymer elastic matrix phase to react with the active groups (hydroxyl and amino groups) of the liquid crystal functional phase, such as nucleophilic ring-opening / addition reactions, free radical grafting reactions, or click chemistry reactions, to form stable chemical covalent bonds, constituting the strongest first-level strong interaction. On the other hand, the high shear generated by hot melt extrusion in-situ crosslinking spinning treatment... The shear field can drive the long molecular chain segments of the two phases to diffuse and entangle into each other, so that the molecular chains of the thermoplastic polymer elastic matrix phase can generate sufficient physical entanglement density in the bonding interface region. The entangled molecular chains of the thermoplastic polymer elastic matrix phase will wrap the rigid liquid crystal functional phase network, forming secondary interactions including hydrogen bonding forces and a large number of van der Waals forces. This constitutes the second and third level bonding forces, which are relatively weak but have a wide range. This continuous distribution from the first level strong covalent bonds to the subsequent multiple weak interactions can form a modulus smooth transition gradient layer in the bonding interface region.

[0086] It is also understandable that cooling treatment can quickly fix the initial shape of the fiber sample, ensure the dimensional stability of the fiber sample, and avoid structural deformation problems during subsequent drawing processes.

[0087] In one embodiment, the temperature during the hot melt extrusion in-situ crosslinking spinning process is 160℃-200℃ to ensure that the liquid crystal monomer can undergo a sufficient in-situ crosslinking reaction inside the thermoplastic polymer matrix. The screw speed during extrusion is controlled at 30rpm-150rpm to ensure that the high shear force field generated by the hot melt extrusion in-situ crosslinking spinning process can achieve sufficient diffusion and entanglement of the two phases, which is beneficial for preparing a suitable modulus smooth transition gradient layer.

[0088] In one embodiment, the hot melt extrusion in-situ crosslinking spinning process includes the following steps: adding composite masterbatch C into a hot melt extrusion device, completely melting it at a temperature of 160℃-200℃, and then starting a UV lamp with a center wavelength of 365nm, setting the irradiation intensity to 80mW / cm². 2 -150mW / cm 2 The extrusion screw speed is 30rpm-150rpm to achieve gradient coupling and topological interlocking between the thermoplastic polymer elastic matrix phase and the liquid crystal functional phase.

[0089] S105. The fiber sample is subjected to a stretching treatment to obtain the high fatigue resistance, high responsiveness, and high elasticity fiber material described in any of the above embodiments. It can be understood that stretching can orient the molecular chains of the thermoplastic polymer elastic matrix phase along the stretching direction, improving the mechanical strength and fatigue resistance of the high fatigue resistance, high responsiveness, and high elasticity fiber material. Oriented molecular chains can more uniformly disperse external forces, reducing stress concentration. Simultaneously, stretching can further improve the alignment degree of the liquid crystal functional phase units, enhancing the response sensitivity and deformation of the high fatigue resistance, high responsiveness, and high elasticity fiber material, ensuring that the finally prepared high fatigue resistance, high responsiveness, and high elasticity fiber material simultaneously possesses high-efficiency stimulus response, high elasticity and toughness, and excellent fatigue resistance.

[0090] The following are some specific examples. When %, it refers to a percentage by weight. It should be noted that the following examples do not exhaustively list all possible scenarios, and unless otherwise specified, the materials used in the examples are commercially available.

[0091] Example 1 1) 18g of liquid crystal monomer RM257, 5g of chain extender (1,6-hexanedithiol), 2g of catalyst (triethylamine), 2g of crosslinking agent (tracelyl isocyanurate), 1g of initiator (benzoyl peroxide), and 1g of carboxylated multi-walled carbon nanotubes were used as LCE precursors. The above components were placed in a specific temperature field formed by a constant temperature water bath at 75°C in a light-protected environment. First, the components were initially mixed by magnetic stirring (600 rpm) for 1 h to ensure initial compatibility. Then, the mixture was switched to mechanical stirring (1000 rpm) for high-speed stirring for 2 h to obtain precursor solution A for preparing the liquid crystal functional phase. 2) 71g of thermoplastic polymer elastic matrix SEBS-g-MAH (weight average molecular weight (M... w ) is 2.0 × 10 5 The precursor solution B for preparing the thermoplastic polymer elastic matrix phase was prepared by mixing the solution (g / mol) in 215g solvent (tetrahydrofuran) with mechanical stirring (600rpm) for 2h. 3) Introduce precursor solution A from step 1) into precursor solution B from step 2), and perform intermittent ultrasonic treatment using a high-power probe (500W power, 40kHz frequency) for 30 minutes to obtain a mixture; then transfer it to a high-speed centrifuge / vacuum degassing integrated device, and process it at 5000rpm for 15 minutes under a vacuum of 80kPa. After that, place it in a vacuum drying oven for gradient desolventizing treatment: in the first desolventizing stage, set the vacuum degree to 20kPa-40kPa and let it stand at room temperature for 4 hours; in the second desolventizing stage, set the vacuum degree to above 95kPa and simultaneously raise the temperature to 75℃ for 8 hours to completely remove residual solvent, and obtain composite masterbatch C with highly compatible components, no bubbles and uniform microstructure.

[0092] 4) Add composite masterbatch C to the hot melt extrusion equipment and melt it completely at 180℃. Then, turn on the UV lamp assembly with a center wavelength of 365nm and set the UV light intensity to 120mW / cm². 2 In-situ cross-linking spinning was performed under the condition that the extrusion screw speed was 80 rpm, and after cooling, fiber samples with gradient coupling and topological interlocking interfaces were obtained. 5) The fiber sample was post-treated and stretched, and then water-cooled and dried to obtain a high fatigue resistance, high response and high elasticity fiber material with a diameter of 200µm.

[0093] Example 2: The only difference from Example 1 is that the liquid crystal monomer RM257 in step 1) is replaced with the thermally responsive monomer RM82, and the temperature of the in-situ crosslinking spinning process in step 4) is adjusted according to the melting point of RM82. Everything else remains the same.

[0094] Example 3: The only difference from Example 1 is that the thermoplastic polymer elastic matrix SEBS-g-MAH in step 2) is replaced with thermoplastic polyamide elastomer (PEBA), and the temperature of the in-situ crosslinking spinning treatment in step 4) is adjusted according to the PEBA. The rest remains unchanged.

[0095] Example 4: The only difference from Example 1 is that the 18g liquid crystal monomer RM257 in step 1) is replaced with 36g liquid crystal monomer RM257, and the 71g thermoplastic polymer elastic matrix SEBS-g-MAH in step 2) is replaced with 53g thermoplastic polymer elastic matrix phase SEBS-g-MAH, while the rest remain unchanged.

[0096] Example 5: The only difference from Example 1 is that 5g of azobenzene photoresponsive monomer is added in step 1), and 71g of thermoplastic polymer elastic matrix SEBS-g-MAH in step 2) is replaced with 66g of thermoplastic polymer elastic matrix SEBS-g-MAH, while the rest remains unchanged.

[0097] Comparative Example 1: The only difference from Example 1 is that the thermoplastic polymer elastic matrix SEBS-g-MAH (weight-average molecular weight (M)) in step 2) is changed. w ) is 2.0 × 10 5 Replace g / mol) with the thermoplastic polymer elastic matrix SEBS-g-MAH (weight-average molecular weight (M) w The value is 8.1 × 10 4 g / mol), the rest remain unchanged.

[0098] Comparative Example 2: The only difference from Example 1 is that the thermoplastic polymer elastic matrix SEBS-g-MAH (weight-average molecular weight (M)) in step 2) is changed. w ) is 2.0 × 10 5 Replace g / mol) with the thermoplastic polymer elastic matrix SEBS-g-MAH (weight-average molecular weight (M) w ) is 3.0×10 5 g / mol), the rest remain unchanged.

[0099] Comparative Example 3: The only difference from Example 1 is that the 215g solvent in step 2) is added in step 1), i.e., step 2) only contains 71g of thermoplastic polymer elastic matrix SEBS-g-MAH (weight average molecular weight (M)). w ) is 2.0 × 10 5 g / mol), the rest remain unchanged.

[0100] Comparative Example 4: The only difference from Example 1 is that step 3) of intermittent ultrasound for 30 minutes is omitted, which is continuous ultrasound; the rest remains the same.

[0101] Comparative Example 5: The only difference from Example 1 is that the power of 500W and frequency of 40kHz in step 3) is replaced with the power of 600W and frequency of 15kHz, while the rest remain unchanged.

[0102] Comparative Example 6: The only difference from Example 1 is that the second desolventizing stage in step 3) is omitted, while the rest remains the same.

[0103] Comparative Example 7: The only difference from Example 1 is that the screw speed of 80 rpm in step 4) is replaced with a screw speed of 20 rpm, while the rest remain unchanged.

[0104] The high fatigue resistance, high response, and high elasticity fiber materials prepared in Examples 1-5 and Comparative Examples 1-7 were tested for elongation at break (%), reversible response deformation (%), and cycle life (cycles), and the experimental data are shown in Table 1 below: The method for testing elongation at break was as follows: Referencing GB / T 14344-2022 "Test Method for Tensile Properties of Chemical Fiber Filaments". A constant rate of elongation (CRE) universal testing machine was used, with a spacing length of 30 mm, a tensile speed of 20 mm / min, an ambient temperature of 20 ± 2℃, and a relative humidity of 65% ± 5%. The elongation at break was calculated by recording the ratio of the elongation at break to the initial spacing length. Detection method for reversible response deformation: In-situ microscopic imaging analysis was employed. A single fiber was placed horizontally under a polarizing microscope equipped with a temperature-controlled stage. Under no-load conditions, the length change of the fiber before and after stimulation was captured by a digital imaging system. The initial temperature (isotropic state) was set to 25℃, and the response temperature to 100℃. After the length stabilized, the fiber length was measured using image processing software and calculated according to the formula Ɛ=(L0-L) / L0×100%. Each group of samples was tested 5 times, and the average value was taken. Method for testing response cycle life: A dynamic thermomechanical fatigue testing system was used. The initial fiber pretension was set to 0.1 cN / dtex, and continuous heating and cooling cycles were performed within a specific temperature range (e.g., 25℃-100℃). The reversible shrinkage rate was recorded every 100 cycles. Judgment criteria: When the reversible response deformation of the fiber decayed to less than 80% of the initial value (i.e., the decay rate exceeded 20%) or the fiber physically broke, the test was stopped, and the number of cycles at this point was recorded as the response cycle life. The method for testing elastic recovery rate is as follows: Refer to GB / T 14344-2022 "Test Method for Tensile Properties of Chemical Fiber Filaments" and combine it with the characteristics of this fiber. At 20℃, a fiber of length L0 (30 mm) is stretched to 50% strain (L) at a speed of 20 mm / min. max =45mm), hold at this position for 1 minute to allow the stress to fully relax. Unload at the same speed until the force value is zero, the fiber rebounds, and the length L1 at this point is recorded; keep in an unloaded state, immediately apply environmental stimulation (such as heating or ultraviolet light irradiation of a specific intensity), and use the liquid crystal phase contraction force to drive the fiber to further reset, and record the final length L2 after the length stabilizes. Final elastic recovery rate R e =(L max -L2) / (L max -L0)x100%.

[0105] Table 1 Summary of Comprehensive Performance Data As can be seen from Examples 1-5 in Table 1 above, under the same ratio, the comprehensive performance of the high fatigue resistance, high response, and high elastic fiber material obtained by combining liquid crystal monomer (RM257) with thermoplastic polymer elastic matrix phase (SEBS-g-MAH) is significantly better than that of RM82 / SEBS-g-MAH and RM257 / PEBA. Among them, Example 1 has the best comprehensive index.

[0106] A comparison of Example 1 and Comparative Examples 1-2 shows that, due to the lower weight-average molecular weight (Mb) of the thermoplastic polymer elastic matrix phase SEBS-g-MAH in Example 1, the molecular weight of the thermoplastic polymer elastic matrix phase SEBS-g-MAH is significantly lower. w ) at 8.2×10 4 g / mol - 2.5 × 10 5 The g / mol ratio makes the overall performance of Example 1 significantly better than that of Comparative Examples 1-2.

[0107] As can be seen from the comparison between Example 1 and Comparative Example 3, the solvent in Example 1 can fully wet and swell the thermoplastic polymer elastic matrix, while the solvent in Comparative Example 3 is mixed with the liquid crystal monomer and cannot effectively wet and swell the thermoplastic polymer elastic matrix, resulting in the overall performance of Comparative Example 3 being significantly worse than that of Example 1.

[0108] As can be seen from the comparison between Example 1 and Comparative Example 4, the residual heat generated by the continuous ultrasonic treatment in Comparative Example 4 causes the thermoplastic polymer elastic matrix and liquid crystal monomer to crosslink prematurely, resulting in the overall performance of Comparative Example 4 being significantly worse than that of Example 1.

[0109] As can be seen from the comparison between Example 1 and Comparative Example 5, since the power of the continuous ultrasonic treatment in Comparative Example 5 is not in the range of 300W-500W and the frequency is not in the range of 20kHz-40kHz, the overall performance of Comparative Example 5 is significantly worse than that of Example 1.

[0110] As can be seen from the comparison between Example 1 and Comparative Example 6, since Comparative Example 6 only uses the first desolventizing stage, a large amount of solvent remains in the composite masterbatch C, resulting in the overall performance of Comparative Example 6 being significantly worse than that of Example 1.

[0111] As can be seen from the comparison between Example 1 and Comparative Example 7, since the screw speed of Comparative Example 7 is not in the range of 30rpm-150rpm, it cannot provide a high shear force field, resulting in the overall performance of Comparative Example 7 being significantly worse than that of Example 1.

[0112] The embodiments described above are merely illustrative of several implementations of this disclosure, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the disclosed patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this disclosure, and these all fall within the protection scope of this disclosure. Therefore, the protection scope of this patent should be determined by the appended claims.

Claims

1. A high-fatigue-resistant, high-response, and high-elasticity fiber material, comprising a liquid crystal functional phase, characterized in that, The high fatigue resistance, high response, and high elasticity fiber material also includes a thermoplastic polymer elastic matrix phase. The thermoplastic polymer elastic matrix phase and the liquid crystal functional phase form a modulus smooth transition gradient layer at the interface of the two phases through gradient coupling and topological interlocking. The modulus smooth transition gradient layer is used to efficiently transfer strain and smoothly dissipate stress. The thermoplastic polymer elastic matrix phase contains active groups, which include at least one of acid anhydride, epoxy, carboxyl, hydroxyl, amine and unsaturated double bond; The weight-average molecular weight (M) of the thermoplastic polymer elastic matrix phase w The value is 8.2 × 10 4 g / mol - 2.5 × 10 5 g / mol; The amount of the thermoplastic polymer elastic matrix phase used is 50-90 parts by weight.

2. The high fatigue resistance, high response, and high elasticity fiber material according to claim 1, characterized in that, The thermoplastic polymer elastic matrix phase includes at least one of styrene block copolymers, thermoplastic polyester elastomers, thermoplastic polyurethane elastomers, and dynamically vulcanized thermoplastic elastomers.

3. The high fatigue resistance, high response, and high elasticity fiber material according to claim 2, characterized in that, The styrene block copolymers include at least one of maleic anhydride-grafted styrene-butadiene-styrene block copolymers and epoxidized styrene-butadiene-styrene block copolymers; and / or The thermoplastic polyester elastomer comprises at least one of polybutylene terephthalate-polytetrahydrofuran ether block copolymer and maleic anhydride-grafted thermoplastic polyester elastomer; and / or, The thermoplastic polyurethane elastomer includes at least one of polyester-type polyurethane elastomers and polyether-type polyurethane elastomers; and / or, The dynamically vulcanized thermoplastic elastomer includes a polypropylene / ethylene propylene diene monomer (EPDM) rubber blend vulcanization system.

4. The high fatigue resistance, high response, and high elasticity fiber material according to claim 1, characterized in that, The high elasticity of the high fatigue resistance, high response, and high elastic fiber material refers to a breaking elongation > 300%; and / or... The high fatigue resistance of the high fatigue-resistant, high-response, and high-elastic fiber material refers to an elastic recovery rate of >85% at 50% strain; and / or, The high response of the high fatigue resistance, high response, and high elastic fiber material refers to the reversible response deformation of the high fatigue resistance, high response, and high elastic fiber material being 5%-50%, and the response cycle life of the high fatigue resistance, high response, and high elastic fiber material being >5000 cycles.

5. The high fatigue resistance, high response, and high elasticity fiber material according to claim 1, characterized in that, The monofilament diameter of the high fatigue resistance, high response, and high elasticity fiber material is 50µm-1000µm.

6. The high fatigue resistance, high response, and high elasticity fiber material according to claim 1, characterized in that, The amount of the liquid crystal functional phase used is 10 to 50 parts by weight.

7. A method for preparing a high fatigue-resistant, high-response, and high-elastic fiber material, characterized in that, Includes the following steps: Liquid crystal monomers, chain extenders, catalysts, crosslinking agents and initiators are mixed to obtain a precursor solution A of the liquid crystal functional phase; A thermoplastic polymer elastic matrix and a solvent are mixed to obtain a precursor solution B of the thermoplastic polymer elastic matrix phase; The precursor solution A and the precursor solution B are subjected to intermittent ultrasonic treatment to obtain a mixture; wherein the conditions for the intermittent ultrasonic treatment are: power of 300W-500W, frequency of 20kHz-40kHz, and time of 30min-60min. The mixture was subjected to vacuum centrifugation and degassing followed by gradient desolventizing to obtain composite masterbatch C. The composite masterbatch C was subjected to hot melt extrusion in-situ crosslinking spinning treatment, and fiber samples were obtained after cooling. The fiber sample is subjected to a stretching process to obtain the high fatigue resistance, high response, and high elasticity fiber material as described in any one of claims 1-6.

8. The method for preparing the high fatigue resistance, high response, and high elasticity fiber material according to claim 7, characterized in that, The conditions for the vacuum centrifugation degassing treatment are: vacuum degree of 80kPa-100kPa, rotation speed of 3000rpm-5000rpm, and time of 10min-20min.

9. The method for preparing the high fatigue resistance, high response, and high elasticity fiber material according to claim 7, characterized in that, The gradient desolventizing process includes a first desolventizing stage and a second desolventizing stage. The conditions for the first desolventizing stage are: vacuum degree of 20kPa-40kPa and standing at room temperature for 4h-6h. The conditions for the second solvent removal stage are: vacuum degree > 95 kPa, temperature 55℃-85℃ for 6h-12h.

10. The method for preparing the high fatigue resistance, high response, and high elasticity fiber material according to claim 7, characterized in that, The temperature during the hot melt extrusion in-situ crosslinking spinning process is 160℃-200℃, and the screw speed during extrusion is controlled at 30rpm-150rpm; and / or, In the step of mixing the liquid crystal monomer, chain extender, catalyst, crosslinking agent, and initiator, a low-dimensional nanofiller is also added; and / or, The liquid crystal monomer includes at least one of the following: thermally responsive nematic liquid crystal monomer, chiral liquid crystal monomer, chiral doped liquid crystal monomer, photoresponsive liquid crystal monomer, ionic liquid crystal monomer, hydrogen-containing liquid crystal monomer, and siloxane liquid crystal monomer.

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