A heat and moisture dual-response intelligent knitted fabric and a preparation method thereof

Abstract

This invention relates to a thermo- and moisture-responsive smart knitted fabric and its preparation method. The fabric includes a fabric substrate and a thermo-responsive shape memory coated yarn embedded within the fabric substrate. Moisture-responsive modified wool yarn and Artemisia argyi yarn are interwoven in the fabric substrate to form an open-knitted structure with air layers. The thermo-responsive shape memory coated yarn is a three-dimensional network structure coated yarn formed by coating the surface of Artemisia argyi yarn with a polycaprolactone / polyethylene glycol blend solution and crosslinking it under ultraviolet light under the action of a photoinitiator and a crosslinking agent. The moisture-responsive modified wool yarn is a wool yarn treated with sodium hypochlorite. The thermo-responsive shape memory coated yarn is threaded into the fabric from the reverse loop of the moisture-responsive modified wool yarn. Utilizing the melt-induced shrinkage effect of the thermo-responsive shape memory coated yarn under temperature and the moisture-absorbing deformation behavior of the moisture-responsive modified wool yarn under humidity, a synergistic coupling of structural relaxation and driving enhancement is achieved, applicable to the fields of smart clothing and human body thermo- and moisture-regulating systems.

Description

Technical Field

[0001] This invention relates to the field of smart textile materials and shape memory polymer technology, specifically to a heat and moisture dual-response smart knitted fabric and its preparation method. Background Technology

[0002] With the increasing demand for comfort and intelligence in clothing, intelligent responsive textiles have become an important research direction in materials science and textile engineering. The temperature and humidity of the human body's microclimate fluctuate significantly under different environmental and exercise conditions. For example, in high temperatures or during exercise, the body surface temperature rises and is accompanied by profuse sweating, while in static or low-temperature environments, it exhibits low temperature and low humidity characteristics. Ideal intelligent clothing should be able to autonomously adjust its breathability, thermal conductivity, and moisture transfer properties according to these dynamic changes, thereby achieving precise control over the body's thermal and humidity comfort. Existing research has developed various functional fabrics for single-stimuli response. Studies have shown that through material design or structural control, fabrics can respond to external stimuli, thereby improving the body's thermal and humidity comfort to a certain extent.

[0003] Currently, functional textiles used for thermo-humidity regulation are mainly based on the aforementioned single regulation mechanisms. For example, heat-responsive fabrics typically rely on phase change materials or thermosensitive polymers undergoing phase changes or deformations at specific temperatures to adjust their heat retention properties; moisture-responsive fabrics mainly rely on moisture-absorbing and expanding fibers or hydrogel materials undergoing volume changes during moisture absorption, thereby passively altering the fabric's pore structure. Typical examples include PNIPAM-based thermosensitive fabrics undergoing hydrophilic-hydrophobic transitions near critical temperatures, and hydrogel fibers expanding in high-humidity environments to increase breathability. However, changes in the human body's microclimate are essentially a dynamic process of coupled temperature and humidity evolution. For instance, during exercise, increased body surface temperature is accompanied by increased sweat secretion, requiring not only enhanced heat dissipation but also accelerated moisture excretion; conversely, in low-temperature environments, it is necessary to simultaneously suppress heat loss and moisture evaporation. Therefore, relying solely on a single response mechanism is insufficient to achieve synergistic regulation of heat and moisture, resulting in limited fabric adaptability in complex environments.

[0004] Furthermore, existing thermo- and moisture-controlled fabrics still have significant shortcomings in structural design: most fabrics have fixed pore structures and lack reversible adjustment capabilities; there is a lack of effective coupling between thermal and moisture response mechanisms, with functional superposition often achieved through simple layering or finishing methods, resulting in low structural integration, poor synergy of responses, and insufficient long-term stability. Although stimulus-responsive materials (such as shape memory materials and moisture-responsive materials) have been extensively studied, their functions are mostly limited to the material level, and synergistic coupling and regulation of thermal and moisture responses have not yet been achieved at the fabric structural scale, thus limiting their further application in the field of smart clothing. Summary of the Invention

[0005] This invention aims to address the problems of single response mechanism, asynchronous temperature and humidity regulation, and insufficient structural stability in existing smart textile technologies, and provides a temperature and humidity dual-response smart knitted fabric and its preparation method. This knitted fabric can achieve coordinated deformation of the fabric structure and dynamic regulation of the opening structure under coupled temperature and humidity changes, thereby enhancing the fabric's adaptive adjustment capability to the human body's microclimate.

[0006] This invention also provides a method for preparing a heat- and moisture-responsive smart knitted fabric. Based on an air-layer open knitted structure, in-situ photocrosslinking technology imparts a reversible thermo-induced shape memory effect to the Artemisia / polycaprolactone / polyethylene glycol composite yarn, while ultrasonic chlorination technology imparts sensitive moisture-induced deformation capabilities to the wool yarn. Utilizing the synergistic coupling effect between the thermo-induced shrinkage of the heat-responsive yarn and the moisture absorption and expansion of the moisture-responsive yarn, the fabric's open structure is driven to dynamically open and close under heat and moisture conditions. This results in significantly higher heat and moisture regulation efficiency and response sensitivity compared to fabrics with a single response mechanism, thereby achieving dynamic regulation of the body surface microclimate and improved comfort.

[0007] The technical problem solved by this invention is achieved through the following technical solution: A heat and moisture dual-response smart knitted fabric includes a fabric substrate and a heat-responsive shape memory coated yarn embedded in the fabric substrate; The fabric base includes a wet-response modified wool yarn for the woven surface layer and an artemisia yarn for the woven bottom layer. The wet-response modified wool yarn and the artemisia yarn are interwoven to form an open knitted structure with an air layer. The thermally responsive shape memory coated yarn is a three-dimensional network structure coated yarn formed by coating the surface of Artemisia argyi yarn with a polycaprolactone / polyethylene glycol blend solution and cross-linking under ultraviolet light under the action of photoinitiator and cross-linking agent. The wet-responsive modified wool yarn is a wool yarn that has been chlorinated with sodium hypochlorite. The heat-responsive shape memory coated yarn is inserted into the fabric from the reverse loop of the wet-responsive modified wool yarn in a crosswise and / or longitudinal manner, using an interlocking method of 1-through-1 or 2-through-2.

[0008] Furthermore, the crosslinking agent is triallyl isocyanurate, the photoinitiator is benzophenone, and the mass ratio of triallyl isocyanurate to benzophenone is 1:1.

[0009] A method for preparing a heat and moisture dual-response smart knitted fabric includes the following steps: Step 1: Prepare thermally responsive shape memory coated yarn: (1) Preparation of polycaprolactone / polyethylene glycol blend solution: Polycaprolactone and polyethylene glycol were added to dichloromethane at a mass ratio of 10:0 to 6:4 and stirred at room temperature until completely dissolved to obtain a polycaprolactone / polyethylene glycol blend solution. (2) Preparation of coating solution containing photoinitiator and crosslinking agent: Add benzophenone and triallyl isocyanurate in a mass ratio of 1:1 to a polycaprolactone / polyethylene glycol blend solution, wherein the total amount of benzophenone and triallyl isocyanurate added is 3wt% to 9wt% of the total mass of the blend solution. Continue stirring for 1.5h until the mixture is uniform to obtain a coating solution containing photoinitiator and crosslinking agent. (3) Yarn coating and drying: The Artemisia argyi yarn is immersed in a coating solution containing a photoinitiator and a crosslinking agent, or the coating solution is uniformly coated onto the surface of the Artemisia argyi yarn, and then dried at room temperature in a ventilated place to remove the dichloromethane solvent, thus obtaining a dry coated yarn. (4) Ultraviolet crosslinking treatment: The dried coated yarn is subjected to cross-linking treatment by irradiating it under ultraviolet light for 20 minutes. Benzophenone and triallyl isocyanurate are then subjected to free radical polymerization in a mixture of polycaprolactone and polyethylene glycol to form a three-dimensional network structure coated yarn, thus obtaining a thermally responsive shape memory coated yarn.

[0010] Step 2: Preparation of wet-response modified wool yarn: (1) Preparation of sodium hypochlorite chlorination reaction solution: Add 6-12 mL of 5% sodium hypochlorite solution to deionized water and bring the volume up to 50 mL. Then add 0.5 g of nano calcium carbonate and 0.13 mL of hydrochloric acid. Stir at room temperature for 30 min until uniformly dispersed to obtain sodium hypochlorite chlorination reaction solutions of different concentrations. (2) Ultrasonic chlorination treatment: The wool yarn was completely immersed in sodium hypochlorite chlorination reaction solution and placed in an ultrasonic cleaner for 30-60 minutes at a frequency of 35kHz and a power of 40W. (3) Washing and drying: The wool yarn after ultrasonic chlorination treatment is taken out, washed with deionized water until neutral, and dried in an oven at 50°C to obtain wet-response modified wool yarn.

[0011] Step 3: Prepare a heat and moisture dual-response smart knitted fabric: (1) Fabric base for weaving: Using a computerized flat knitting machine, wet-responsive modified wool yarn and artemisia yarn are interwoven to weave a fabric base with an open air layer structure. The number of open needles is 12, 16, 20 or 24. The wet-responsive modified wool yarn is used to weave the surface layer and the artemisia yarn is used to weave the bottom layer. (2) Embedded thermally responsive shape memory coated yarn: By inserting heat-responsive shape memory coated yarn from the reverse loop of wet-responsive modified wool yarn into the internal structure of the fabric in a way that alternates between 1 or 2 loops, a heat- and moisture-responsive smart knitted fabric is obtained.

[0012] Furthermore, in step 1, the mass ratio of polycaprolactone to polyethylene glycol is 8:2, and the total amount of benzophenone and triallyl isocyanurate added is 5 wt%.

[0013] Furthermore, in step 2, the amount of sodium hypochlorite chlorination reaction solution added is 10 mL, and the ultrasonic treatment time is 40 min.

[0014] Furthermore, in step 3, the number of opening needles in the air layer opening structure is 20, and the embedding method is longitudinal, with 2 needles inserted every other needle.

[0015] The advantages and positive effects of this invention are: 1. This invention constructs a dual-function yarn synergistic driving system by introducing thermally responsive shape memory coated yarn and wet-responsive modified wool yarn into the knitted structure, realizing the coupling of thermal response and wet response at the fabric structure level, which significantly improves environmental adaptability compared with existing single-response fabrics.

[0016] 2. This invention utilizes the synergistic effect between the thermal response shrinkage driving force and the wet response structural relaxation effect to enable the fabric opening structure to achieve dynamic control under temperature and humidity coupling conditions, thus solving the problems of asynchronous response and low control efficiency in traditional fabrics.

[0017] 3. The fabric of this invention exhibits significant improvements in structural response and transmission performance in high temperature and high humidity environments. Its air permeability, moisture permeability, and thermal conductivity are all significantly better than those of conventional fabrics, realizing the transformation from static heat preservation to dynamic heat dissipation.

[0018] 4. The thermally responsive shape memory coated yarn or wet-responsive modified wool yarn of the present invention can be used directly as a raw material for textile processing. It can be woven on conventional knitting equipment without complex finishing processes, and has good process adaptability and potential for large-scale application.

[0019] 5. This invention utilizes the melt-induced shrinkage effect of thermally responsive shape memory coated yarn under temperature and the moisture-absorbing deformation behavior of moisture-responsive modified wool yarn under humidity to achieve a synergistic coupling of structural relaxation and driving enhancement: the thermally responsive shape memory coated yarn provides the dominant driving force through axial shrinkage under heating conditions, while the moisture-responsive modified wool yarn exhibits axial elongation and diameter reduction after absorbing water, leading to a decrease in inter-yarn contact pressure and weakened coil constraint, generating a moisture-induced "relaxation effect." This reduces bending stiffness, weakens structural constraint, and makes the thermal shrinkage driving force more likely to induce fabric instability and rollover, achieving a transformation from a planar state to a three-dimensional arched shape. By optimizing the air layer opening structure parameters, such as the arrangement ratio of thermally responsive and moisture-responsive yarns and the coil density, a balance between structural stiffness and relaxation is achieved, thereby realizing dynamic control of the fabric's pore structure. When the water absorption rate increases from 0 to 100%, the diameter of the coil pores on the reverse side of the fabric increases from 0.12 mm to 0.28 mm, and the pore area ratio increases from 18.5% to 34.2%, demonstrating a significant humidity response regulation capability. Driven by the combined effects of 50℃ and 100% water absorption rate, the shrinkage resistance of the heat-responsive shape memory coated yarn is significantly reduced, the vertical roll-up height of the fabric reaches 3.561 mm, and the air permeability and moisture permeability reach 310 mm / s and 790 g / (m²), respectively. 2 The thermal conductivity jumps from 0.15 W / (m·K) at room temperature to 0.24 W / (m·K), achieving a smart transformation from heat preservation to heat dissipation. This fabric exhibits excellent structural responsiveness and weaving adaptability, making it suitable for applications in smart clothing and human body temperature and humidity control. Attached Figure Description

[0020] Figure 1 (a) is a diagram showing the unidirectional shape memory performance of thermally responsive shape memory coated yarns with different mass ratios of polycaprolactone (PCL) and polyethylene glycol (PEG) in Examples 1 and 2 of the present invention; Figure 1 (b) is a diagram showing the bidirectional shape memory properties of thermally responsive shape memory coated yarns with different mass ratios of polycaprolactone (PCL) and polyethylene glycol (PEG) in Examples 1 and 2 of the present invention; Figure 1 (c) is a diagram showing the bidirectional shape memory properties of the thermally responsive shape memory coated yarns with different contents of benzophenone (BP) and triallyl isocyanurate (TAIC) in Examples 1 and 3 of the present invention; Figure 2 (a) is a shape memory performance diagram of wet-response modified wool yarn treated with different sodium hypochlorite concentrations in Examples 1 and 2 of the present invention; Figure 2 (b) is a shape memory performance diagram of wet-response modified wool yarns treated with different chlorination times in Examples 1 and 3 of the present invention; Figure 3 (a) is a diagram of the reverse coil structure of the wet-response modified wool yarn in the dry state according to Embodiment 1 of the present invention; Figure 3 (b) is a diagram of the reverse coil structure of the wet-response modified wool yarn in Example 1 of the present invention in a wet state; Figure 4 (a) shows the air permeability of heat and moisture dual-response smart knitted fabrics with different opening needle counts in Examples 1 and 4 of the present invention at different temperatures; Figure 4 (b) shows the air permeability of the heat and moisture dual-response smart knitted fabrics with different opening needle counts in Examples 1 and 4 of the present invention under different water absorption rates; Figure 5 (a) is a graph showing the moisture permeability of heat and moisture dual-response smart knitted fabrics with different opening needle counts in Examples 1 and 4 of the present invention at different temperatures; Figure 5 (b) is a graph showing the moisture permeability of heat and moisture dual-response smart knitted fabrics with different opening needle counts in Examples 1 and 4 of the present invention under different water absorption rates; Figure 6 The graphs show the thermal conductivity of heat and moisture dual-response smart knitted fabrics with different opening needle counts in Examples 1 and 4 of the present invention at different temperatures. Detailed Implementation

[0021] The present invention will be further described in detail below through specific embodiments. The following embodiments are merely descriptive and not limiting, and should not be used to limit the scope of protection of the present invention.

[0022] A heat and moisture dual-response smart knitted fabric includes a fabric substrate and heat-responsive shape memory coated yarns embedded in the fabric substrate; the fabric substrate includes a moisture-responsive modified wool yarn for the woven surface layer and an artemisia yarn for the woven bottom layer, the moisture-responsive modified wool yarn and the artemisia yarn interlacing to form an air-layer open knitted structure.

[0023] The thermally responsive shape memory coated yarn is a three-dimensional network structure coated yarn formed by coating the surface of Artemisia argyi yarn with a polycaprolactone / polyethylene glycol (PCL / PEG) blend solution and crosslinking it under ultraviolet light in the presence of a photoinitiator and a crosslinking agent. It generates shrinkage driving force under elevated temperature conditions. The crosslinking agent is triallyl isocyanurate (TAIC), and the photoinitiator is benzophenone (BP). The mass ratio of triallyl isocyanurate (TAIC) to benzophenone (BP) is 1:1.

[0024] The wet-response modified wool yarn is a wool yarn treated with sodium hypochlorite. Its fiber surface scale structure is etched and hydrophilic groups are introduced, which produce a deformation response of axial elongation and radial shrinkage during the moisture absorption process. The heat-responsive shape memory coated yarn is inserted into the fabric from the reverse loop of the wet-responsive modified wool yarn in a crosswise and / or longitudinal manner, with an interlocking pattern of 1-through-1 or 2-through-2, so that the fabric produces a synergistic deformation response under temperature and humidity stimulation.

[0025] The present invention provides a heat and humidity dual-response smart knitted fabric that can achieve coordinated deformation of the fabric structure and dynamic control of the opening structure under coupled temperature and humidity changes, thereby improving the fabric's ability to adapt to the human body's microclimate.

[0026] Example 1 A method for preparing a heat and moisture dual-response smart knitted fabric includes the following steps: Step 1: Prepare thermally responsive shape memory coated yarn: (1) Preparation of polycaprolactone / polyethylene glycol (PCL / PEG) blend solution: Polycaprolactone (PCL) and polyethylene glycol (PEG) were added to dichloromethane at a mass ratio of 8:2 and stirred at room temperature until completely dissolved to obtain a polycaprolactone / polyethylene glycol (PCL / PEG) blend solution. (2) Preparation of coating solution containing photoinitiator and crosslinking agent: Add benzophenone (BP) and triallyl isocyanurate (TAIC) in a mass ratio of 1:1 to a polycaprolactone / polyethylene glycol (PCL / PEG) blend solution, wherein the total amount of benzophenone (BP) and triallyl isocyanurate (TAIC) added is 5 wt% of the total mass of the blend solution. Continue stirring for 1.5 h until the mixture is homogeneous to obtain a coating solution containing photoinitiator and crosslinking agent. (3) Yarn coating and drying: The coating solution containing photoinitiator and crosslinking agent was uniformly coated onto the surface of Artemisia argyi yarn, and then dried at room temperature in a ventilated place to remove the dichloromethane solvent, resulting in a dry coated yarn. (4) Ultraviolet crosslinking treatment: The dried coated yarn is subjected to cross-linking treatment by irradiating it under ultraviolet light for 20 minutes. Benzophenone (BP) and triallyl isocyanurate (TAIC) are then subjected to free radical polymerization in a mixture of polycaprolactone / polyethylene glycol to form a three-dimensional network structure coated yarn, thus obtaining a thermally responsive shape memory coated yarn.

[0027] Step 2: Preparation of wet-response modified wool yarn: (1) Preparation of sodium hypochlorite chlorination reaction solution: Add 10 mL of 5% sodium hypochlorite solution to deionized water and bring the volume up to 50 mL to prepare a 10% solution. Then add 0.5 g of nano calcium carbonate and 0.13 mL of hydrochloric acid and stir at room temperature for 30 min until uniformly dispersed to obtain a sodium hypochlorite chlorination reaction solution with a concentration of 10 g / L. (2) Ultrasonic chlorination treatment: The wool yarn was completely immersed in sodium hypochlorite chlorination reaction solution and placed in an ultrasonic cleaner for 40 minutes at a frequency of 35kHz and a power of 40W. (3) Washing and drying: The wool yarn after ultrasonic chlorination treatment is taken out, washed with deionized water until neutral, and dried in an oven at 50°C to obtain wet-response modified wool yarn.

[0028] Step 3: Prepare a heat and moisture dual-response smart knitted fabric: (1) Fabric base for weaving: Using a computerized flat knitting machine, wet-responsive modified wool yarn and artemisia yarn are interwoven to weave a fabric base with an air-layer open structure, with 20 open stitches; the wet-responsive modified wool yarn is woven into the surface layer, and the artemisia yarn is woven into the bottom layer. (2) Embedded thermally responsive shape memory coated yarn: By inserting heat-responsive shape memory coated yarn from the reverse loop of wet-responsive modified wool yarn into the internal structure of the fabric in a longitudinal direction with an interleaved 2-through-2 embedding method, a heat- and moisture-responsive smart knitted fabric is obtained.

[0029] The heat and moisture dual-response smart knitted fabric prepared in Example 1 exhibited optimal performance. For example... Figure 1 As shown in (a) and (b), the shape fixation rate of the thermally responsive shape memory coated yarn is approximately 91%, the shape recovery rate is nearly 97%, and the reversible strain is approximately 10.1%; Figure 2 As shown in (a) and (b), the wet-response modified wool yarn with a hypochlorous acid concentration of 10 g / L and a treatment time of 40 min reached its maximum and remained stable during the wet-dry cycle; as shown in Table 1 and Figure 3 As shown in (a) and (b), the fabric pore diameter is 0.12 mm when the water absorption rate is 0%, and increases to 0.28 mm when the water absorption rate is 100%. The proportion of the fabric pore area in the wet state increases from 18.5% in the dry state to 34.2%. As can be seen from Table 2, under the dual driving force of 50℃ and 100% water absorption rate, the vertical roll-up height reaches 3.561 mm. Under the synergistic effect of heat and moisture, Figure 4 As can be seen from (a) and (b), the wet air permeability at 50℃ exceeds 370 mm / s. Figure 5 (a) and (b) show that the moisture permeability reaches 790 g / (m³) at 50℃. 2 ·h), Figure 6 It can be seen that the thermal conductivity jumps from 0.15 W / (m·K) at room temperature to about 0.24 W / (m·K) at 50℃, realizing the intelligent transformation from heat preservation to heat dissipation. It has the best comprehensive thermal and humidity management performance. The fabric has good structural response and weaving and processing adaptability, and can be applied to the fields of smart clothing and human body thermal and humidity control.

[0030] Example 2 A method for preparing a heat and moisture dual-response smart knitted fabric includes the following steps: Step 1: Prepare thermally responsive shape memory coated yarn: (1) Preparation of polycaprolactone / polyethylene glycol (PCL / PEG) blend solution: Polycaprolactone (PCL) and polyethylene glycol (PEG) were added to dichloromethane at a mass ratio of 6:4 and stirred at room temperature until completely dissolved to obtain a polycaprolactone / polyethylene glycol (PCL / PEG) blend solution. (2) Preparation of coating solution containing photoinitiator and crosslinking agent: Add benzophenone (BP) and triallyl isocyanurate (TAIC) in a mass ratio of 1:1 to a polycaprolactone / polyethylene glycol (PCL / PEG) blend solution, wherein the total amount of benzophenone (BP) and triallyl isocyanurate (TAIC) added is 5 wt% of the total mass of the blend solution. Continue stirring for 1.5 h until the mixture is homogeneous to obtain a coating solution containing photoinitiator and crosslinking agent. (3) Yarn coating and drying: The coating solution containing photoinitiator and crosslinking agent was uniformly coated onto the surface of Artemisia argyi yarn, and then dried at room temperature in a ventilated place to remove the dichloromethane solvent, resulting in a dry coated yarn. (4) Ultraviolet crosslinking treatment: The dried coated yarn is subjected to cross-linking treatment by irradiating it under ultraviolet light for 20 minutes. Benzophenone (BP) and triallyl isocyanurate (TAIC) are then subjected to free radical polymerization in a mixture of polycaprolactone / polyethylene glycol to form a three-dimensional network structure coated yarn, thus obtaining a thermally responsive shape memory coated yarn.

[0031] Step 2: Preparation of wet-response modified wool yarn: (1) Preparation of sodium hypochlorite chlorination reaction solution: Add 10 mL of 5% sodium hypochlorite solution to deionized water and bring the volume up to 50 mL. Then add 0.5 g of nano calcium carbonate and 0.13 mL of hydrochloric acid. Stir at room temperature for 30 min until uniformly dispersed to obtain a sodium hypochlorite chlorination reaction solution with a concentration of 10 g / L. (2) Ultrasonic chlorination treatment: The wool yarn was completely immersed in sodium hypochlorite chlorination reaction solution and placed in an ultrasonic cleaner for 30 minutes at a frequency of 35kHz and a power of 40W. (3) Washing and drying: The wool yarn after ultrasonic chlorination treatment is taken out, washed with deionized water until neutral, and dried in an oven at 50°C to obtain wet-response modified wool yarn.

[0032] Step 3: Prepare a heat and moisture dual-response smart knitted fabric: (1) Fabric base for weaving: Using a computerized flat knitting machine, wet-responsive modified wool yarn and artemisia yarn are interwoven to weave a fabric base with an air-layer open structure, with 20 open stitches; the wet-responsive modified wool yarn is woven into the surface layer, and the artemisia yarn is woven into the bottom layer. (2) Embedded thermally responsive shape memory coated yarn: By inserting heat-responsive shape memory coated yarn from the reverse loop of wet-responsive modified wool yarn into the internal structure of the fabric in a longitudinal direction with an interleaved 2-through-2 embedding method, a heat- and moisture-responsive smart knitted fabric is obtained.

[0033] The shape memory properties of the thermoresponsive shape memory coated yarns with different polycaprolactone / polyethylene glycol ratios prepared in Example 2 are as follows: Figure 1 As shown in (a) and (b), the thermally responsive yarn exhibits limited performance: excessively high PEG content weakens PCL crystallization; this significantly reduces the shape recovery rate and reversible strain of the thermally responsive yarn, ultimately resulting in a significantly weaker overall thermally driven shrinkage and curling height compared to Example 1. The properties of the prepared wet-response modified wool yarn are as follows: Figure 2 (b) It can be seen that when the treatment time is 30 min, the reversible length change rate is 16.07%, which is 2.21% lower than that in Example 1 (40 min treatment, reversible length change rate 18.28%). This is because when the ultrasonic treatment time is short, the sodium hypochlorite does not oxidize and etch the wool scale layer sufficiently, the amount of hydrophilic cysteine ​​groups introduced is limited, the water penetration capacity and the activation degree of the internal hydrogen bond network of the fiber are insufficient, and the wet response deformation capacity is not fully activated.

[0034] Example 3 A method for preparing a heat and moisture dual-response smart knitted fabric includes the following steps: Step 1: Prepare thermally responsive shape memory coated yarn: (1) Preparation of polycaprolactone / polyethylene glycol (PCL / PEG) blend solution: Polycaprolactone (PCL) and polyethylene glycol (PEG) were added to dichloromethane at a mass ratio of 8:2 and stirred at room temperature until completely dissolved to obtain a polycaprolactone / polyethylene glycol (PCL / PEG) blend solution. (2) Preparation of coating solution containing photoinitiator and crosslinking agent: Add benzophenone (BP) and triallyl isocyanurate (TAIC) in a mass ratio of 1:1 to a polycaprolactone / polyethylene glycol (PCL / PEG) blend solution, wherein the total amount of benzophenone (BP) and triallyl isocyanurate (TAIC) added is 9 wt% of the total mass of the blend solution. Continue stirring for 1.5 h until the mixture is homogeneous to obtain a coating solution containing photoinitiator and crosslinking agent. (3) Yarn coating and drying: The coating solution containing photoinitiator and crosslinking agent was uniformly coated onto the surface of Artemisia argyi yarn, and then dried at room temperature in a ventilated place to remove the dichloromethane solvent, resulting in a dry coated yarn. (4) Ultraviolet crosslinking treatment: The dried coated yarn is subjected to cross-linking treatment by irradiating it under ultraviolet light for 20 minutes. Benzophenone (BP) and triallyl isocyanurate (TAIC) are then subjected to free radical polymerization in a mixture of polycaprolactone / polyethylene glycol to form a three-dimensional network structure coated yarn, thus obtaining a thermally responsive shape memory coated yarn.

[0035] Step 2: Preparation of wet-response modified wool yarn: (1) Preparation of sodium hypochlorite chlorination reaction solution: Add 6 mL of 5% sodium hypochlorite solution to deionized water and bring the volume up to 50 mL. Then add 0.5 g of nano calcium carbonate and 0.13 mL of hydrochloric acid. Stir at room temperature for 30 min until uniformly dispersed to obtain a sodium hypochlorite chlorination reaction solution with a concentration of 6 g / L. (2) Ultrasonic chlorination treatment: The wool yarn was completely immersed in sodium hypochlorite chlorination reaction solution and placed in an ultrasonic cleaner for 40 minutes at a frequency of 35kHz and a power of 40W. (3) Washing and drying: The wool yarn after ultrasonic chlorination treatment is taken out, washed with deionized water until neutral, and dried in an oven at 50°C to obtain wet-response modified wool yarn.

[0036] Step 3: Prepare a heat and moisture dual-response smart knitted fabric: (1) Fabric base for weaving: Using a computerized flat knitting machine, wet-responsive modified wool yarn and artemisia yarn are interwoven to weave a fabric base with an air-layer open structure, with 20 open stitches; the wet-responsive modified wool yarn is woven into the surface layer, and the artemisia yarn is woven into the bottom layer. (2) Embedded thermally responsive shape memory coated yarn: By inserting heat-responsive shape memory coated yarn into the internal structure of the fabric in a 2-through-2 manner from the reverse loop of the wet-responsive modified wool yarn, a heat- and wet-responsive smart knitted fabric is obtained.

[0037] Example 3 prepared thermally responsive shape memory coated yarns with different crosslinking agent concentrations. Figure 1 (c) It can be seen that excessively high crosslinking agent concentration leads to restricted molecular motion and inhibited crystallization behavior. Compared with Example 1, the shape recovery rate and reversible strain of the yarn are significantly reduced; the properties of the prepared wet-response modified wool yarn are as follows: Figure 2 (a) It can be seen that when the sodium hypochlorite concentration is too low (6 g / L), the chlorination on the surface of the wool fibers is insufficient, and the introduction of hydrophilic groups is inadequate. This results in insufficient moisture absorption elongation of the yarn and weak wet response performance. The reversible length change rate of the wet-response yarn in the wet-dry cycle is only maintained at about 11.8%, and the pore opening of the fabric in the moisture-absorbing state is far less than that in Example 1.

[0038] Example 4 A method for preparing a heat and moisture dual-response smart knitted fabric includes the following steps: Step 1: Prepare thermally responsive shape memory coated yarn: (1) Preparation of polycaprolactone / polyethylene glycol (PCL / PEG) blend solution: Polycaprolactone (PCL) and polyethylene glycol (PEG) were added to dichloromethane at a mass ratio of 8:2 and stirred at room temperature until completely dissolved to obtain a polycaprolactone / polyethylene glycol (PCL / PEG) blend solution. (2) Preparation of coating solution containing photoinitiator and crosslinking agent: Add benzophenone (BP) and triallyl isocyanurate (TAIC) in a mass ratio of 1:1 to a polycaprolactone / polyethylene glycol (PCL / PEG) blend solution, wherein the total amount of benzophenone (BP) and triallyl isocyanurate (TAIC) added is 9 wt% of the total mass of the blend solution. Continue stirring for 1.5 h until the mixture is homogeneous to obtain a coating solution containing photoinitiator and crosslinking agent. (3) Yarn coating and drying: The coating solution containing photoinitiator and crosslinking agent was uniformly coated onto the surface of Artemisia argyi yarn, and then dried at room temperature in a ventilated place to remove the dichloromethane solvent, resulting in a dry coated yarn. (4) Ultraviolet crosslinking treatment: The dried coated yarn is subjected to cross-linking treatment by irradiating it under ultraviolet light for 20 minutes. Benzophenone (BP) and triallyl isocyanurate (TAIC) are then subjected to free radical polymerization in a mixture of polycaprolactone / polyethylene glycol to form a three-dimensional network structure coated yarn, thus obtaining a thermally responsive shape memory coated yarn.

[0039] Step 2: Preparation of wet-response modified wool yarn: (1) Preparation of sodium hypochlorite chlorination reaction solution: Add 10 mL of 5% sodium hypochlorite solution to deionized water and bring the volume up to 50 mL. Then add 0.5 g of nano calcium carbonate and 0.13 mL of hydrochloric acid. Stir at room temperature for 30 min until uniformly dispersed to obtain a sodium hypochlorite chlorination reaction solution with a concentration of 10 g / L. (2) Ultrasonic chlorination treatment: The wool yarn was completely immersed in sodium hypochlorite chlorination reaction solution and placed in an ultrasonic cleaner for 40 minutes at a frequency of 35kHz and a power of 40W. (3) Washing and drying: The wool yarn after ultrasonic chlorination treatment is taken out, washed with deionized water until neutral, and dried in an oven at 50°C to obtain wet-response modified wool yarn.

[0040] Step 3: Prepare a heat and moisture dual-response smart knitted fabric: (1) Fabric base for weaving: Using a computerized flat knitting machine, wet-responsive modified wool yarn and artemisia yarn are interwoven to weave a fabric base with an air-layer open structure, with 12 open needles; the wet-responsive modified wool yarn is woven into the surface layer and the artemisia yarn is woven into the bottom layer. (2) Embedded thermally responsive shape memory coated yarn: By inserting heat-responsive shape memory coated yarn from the reverse loop of wet-responsive modified wool yarn into the internal structure of the fabric in a longitudinal direction with an interleaved 2-through-2 embedding method, a heat- and moisture-responsive smart knitted fabric is obtained.

[0041] The heat and humidity responsive smart knitted fabric prepared in Example 4 exhibited a limited upper limit for pore expansion. In this example, due to the limited number of open needles (only 12), the fabric structure was too dense. Under high temperature and humidity conditions, the shrinkage stroke of the heat-responsive yarn was severely limited, resulting in the open structure failing to open fully. Figure 4 (a), (b) Figure 5 (a), (b) Figure 6 As shown in Table 2, under the strongest dual drive of 50℃ and 100% water absorption rate, its vertical roll-up height is constrained by the structure. The wet limit air permeability at 50℃ hovers only around 230mm / s (far lower than 370mm / s in Example 1). The jump in thermal conductivity is also limited, and it fails to achieve the excellent dynamic heat and moisture control effect of the 20-needle structure in Example 1.

[0042] Example 5 A method for preparing a heat and moisture dual-response smart knitted fabric includes the following steps: Step 1: Prepare thermally responsive shape memory coated yarn: (1) Preparation of polycaprolactone / polyethylene glycol (PCL / PEG) blend solution: Polycaprolactone (PCL) and polyethylene glycol (PEG) were added to dichloromethane at a mass ratio of 8:2 and stirred at room temperature until completely dissolved to obtain a polycaprolactone / polyethylene glycol (PCL / PEG) blend solution. (2) Preparation of coating solution containing photoinitiator and crosslinking agent: Add benzophenone (BP) and triallyl isocyanurate (TAIC) in a mass ratio of 1:1 to a polycaprolactone / polyethylene glycol (PCL / PEG) blend solution, wherein the total amount of benzophenone (BP) and triallyl isocyanurate (TAIC) added is 5 wt% of the total mass of the blend solution. Continue stirring for 1.5 h until the mixture is homogeneous to obtain a coating solution containing photoinitiator and crosslinking agent. (3) Yarn coating and drying: The coating solution containing photoinitiator and crosslinking agent was uniformly coated onto the surface of Artemisia argyi yarn, and then dried at room temperature in a ventilated place to remove the dichloromethane solvent, resulting in a dry coated yarn. (4) Ultraviolet crosslinking treatment: The dried coated yarn is subjected to cross-linking treatment by irradiating it under ultraviolet light for 20 minutes. Benzophenone (BP) and triallyl isocyanurate (TAIC) are then subjected to free radical polymerization in a mixture of polycaprolactone / polyethylene glycol to form a three-dimensional network structure coated yarn, thus obtaining a thermally responsive shape memory coated yarn.

[0043] Step 2: Preparation of wet-response modified wool yarn: (1) Preparation of sodium hypochlorite chlorination reaction solution: Add 10 mL of 5% sodium hypochlorite solution to deionized water and bring the volume up to 50 mL. Then add 0.5 g of nano calcium carbonate and 0.13 mL of hydrochloric acid. Stir at room temperature for 30 min until uniformly dispersed to obtain a sodium hypochlorite chlorination reaction solution with a concentration of 10 g / L. (2) Ultrasonic chlorination treatment: The wool yarn was completely immersed in sodium hypochlorite chlorination reaction solution and placed in an ultrasonic cleaner for 40 minutes at a frequency of 35kHz and a power of 40W. (3) Washing and drying: The wool yarn after ultrasonic chlorination treatment is taken out, washed with deionized water until neutral, and dried in an oven at 50°C to obtain wet-response modified wool yarn.

[0044] Step 3: Prepare a heat and moisture dual-response smart knitted fabric: (1) Fabric base for weaving: Using a computerized flat knitting machine, wet-responsive modified wool yarn and artemisia yarn are interwoven to weave a fabric base with an air-layer open structure, with 20 open stitches; the wet-responsive modified wool yarn is woven into the surface layer, and the artemisia yarn is woven into the bottom layer. (2) Embedded thermally responsive shape memory coated yarn: By inserting heat-responsive shape memory coated yarn from the reverse loop of wet-responsive modified wool yarn into the internal structure of the fabric in a transverse manner with an alternate loop, a heat- and moisture-responsive smart knitted fabric is obtained.

[0045] The heat and moisture dual-response smart knitted fabric prepared in Example 5 exhibits limited macroscopic three-dimensional deformation capability. (See Table 1 and...) Figure 5 (a), (b) Figure 6 It is evident that, especially when using a transverse, alternate-one-through-one-through-the-yarn threading method, the transverse driving force direction is inconsistent with the natural roll-up direction of the fabric, and the excessive number of constraint points caused by the alternate-one-through-the-yarn threading severely limits the effective shrinkage length of the heat-responsive yarn. Under 50°C triggering conditions, this transverse short-span puncture trajectory cannot effectively drive the reverse coil to undergo significant unwinding, and the fabric's vertical roll-up height (Hmax) is only 0.296 mm, far lower than the 1.434 mm of Example 1 (longitudinal, alternate-two-through-the-yarn threading). Overall, the intelligent breathability and thermal management performance are significantly inferior to the longitudinal, alternate-two-through-the-yarn threading method of Example 1.

[0046] Table 1 Thermal response performance of Examples 1 and 5

[0047] Table 2. Thermal and moisture management performance of dual-response smart knitted fabrics with different needle counts in Examples 1 and 4.

[0048] The heat and moisture dual-response smart knitted fabric of the present invention achieves its function by relying on the thermo-induced reversible deformation mechanism of the heat-responsive shape memory coated yarn, the moisture-induced reversible deformation mechanism of the moisture-responsive modified wool yarn, and the synergistic heat and moisture regulation mechanism of the two in the fabric. The above three mechanisms are explained below.

[0049] I. Thermo-induced Reversible Deformation Mechanism of Thermally Responsive Shape Memory Coated Yarn: The bidirectional shape memory behavior of thermally responsive coated yarn originates from the synergistic effect of the reversible crystallization-melting phase transition of PCL segments and the BP / TAIC photocrosslinked three-dimensional network. Under ultraviolet light irradiation, BP abstracts hydrogen to generate free radicals, which activate PCL / PEG molecular chains and add to the allyl double bonds of TAIC, forming a stable chemical crosslinked network as a permanent stationary phase. When the temperature is raised above the melting point of PCL, the crystalline regions melt, and the chain segments are in a disordered coiled state. After being stretched by external force, the crosslinked network stores elastic internal stress. When the temperature is lowered, the PCL segments crystallize and orient along the direction of the force, which is macroscopically manifested as crystallization-induced elongation (CIE). When the temperature is raised again, the crystalline regions melt, and the release of internal stress drives the chain segments to return to the coiled conformation, which is macroscopically manifested as melt-induced shrinkage (MIC). Through repeated heating and cooling cycles, the material achieves a reversible transformation between the CIE and MIC mechanisms, endowing the yarn with bidirectional shape memory function. The PEG component is used to regulate the crystallinity and melting temperature of PCL, so that its response temperature range matches the human body surface temperature.

[0050] II. Mechanism of Reversible Deformation in Wet-Response Modified Wool Yarn: The deformation behavior of wet-responsive wool yarn originates from the synergistic effect of the disulfide bond cross-linking network (permanent phase) and the hydrogen bond network (reversible phase) within the fiber. NaClO chlorination treatment etches the surface scale layer and chlorinates the disulfide bonds into hydrophilic cysteine ​​groups (-SO3H), significantly enhancing water permeability. Upon wetting, water molecules enter the amorphous region, disrupting hydrogen bonds, causing molecular chain segment rearrangement, fiber straightening and radial shrinkage, macroscopically manifested as axial elongation and diameter reduction in the yarn. During drying, hydrogen bonds are reconstructed under the new conformation, fixing the temporary shape. Upon reabsorption of water, hydrogen bonds dissociate, the disulfide bond cross-linking network releases entropic elastic internal stress, driving the fiber to return to its initial crimped state, and the yarn recovers its original length. Reversible deformation is achieved through wet-dry cycles.

[0051] III. Mechanism of Co-regulation of Fabric Heat and Moisture: The fabric incorporates heat-responsive yarns embedded in the air-layer opening structure of the moisture-responsive wool yarn weave, achieving a synergistic effect of heat and moisture. During temperature rise, the bottom heat-responsive yarns contract axially, providing an active opening driving force; during moisture absorption, the surface wool yarns elongate axially and decrease in diameter, causing the coil structure to relax and reducing bending stiffness. This moisture-induced relaxation effect weakens structural constraints, making it easier for the heat-shrinkage driving force to induce the fabric to transform from a planar closed state to a three-dimensional arched open state. At room temperature and dryness, the openings are closed, resulting in low thermal conductivity and a heat-insulating state; at high temperature and high humidity, the openings open, causing a step increase in thermal conductivity and a significant improvement in air and moisture permeability, achieving an intelligent transformation from static heat preservation to active heat dissipation.

[0052] Although embodiments and drawings of the present invention have been disclosed for illustrative purposes, those skilled in the art will understand that various substitutions, variations and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the scope of the present invention is not limited to the contents disclosed in the embodiments and drawings.

Claims

1. A heat and moisture dual-response smart knitted fabric, characterized in that: This includes the fabric substrate and the thermally responsive shape memory coated yarn embedded within the fabric substrate; The fabric base includes a wet-response modified wool yarn for the woven surface layer and an artemisia yarn for the woven bottom layer. The wet-response modified wool yarn and the artemisia yarn are interwoven to form an open knitted structure with an air layer. The thermally responsive shape memory coated yarn is a three-dimensional network structure coated yarn formed by coating the surface of Artemisia argyi yarn with a polycaprolactone / polyethylene glycol blend solution and cross-linking under ultraviolet light under the action of photoinitiator and cross-linking agent. The wet-responsive modified wool yarn is a wool yarn that has been chlorinated with sodium hypochlorite. The heat-responsive shape memory coated yarn is inserted into the fabric from the reverse loop of the wet-responsive modified wool yarn in a crosswise and / or longitudinal manner, using an interlocking method of 1-through-1 or 2-through-2.

2. The heat and moisture dual-response smart knitted fabric according to claim 1, characterized in that: The crosslinking agent is triallyl isocyanurate, and the photoinitiator is benzophenone. The mass ratio of triallyl isocyanurate to benzophenone is 1:

1.

3. A method for preparing a heat and moisture dual-response smart knitted fabric as described in any one of claims 1 to 2, characterized in that: Includes the following steps: Step 1: Prepare thermally responsive shape memory coated yarn: (1) Preparation of polycaprolactone / polyethylene glycol blend solution: Polycaprolactone and polyethylene glycol were added to dichloromethane at a mass ratio of 10:0 to 6:4 and stirred at room temperature until completely dissolved to obtain a polycaprolactone / polyethylene glycol blend solution. (2) Preparation of coating solution containing photoinitiator and crosslinking agent: Add benzophenone and triallyl isocyanurate in a mass ratio of 1:1 to a polycaprolactone / polyethylene glycol blend solution, wherein the total amount of benzophenone and triallyl isocyanurate added is 3wt% to 9wt% of the total mass of the blend solution. Continue stirring for 1.5h until the mixture is uniform to obtain a coating solution containing photoinitiator and crosslinking agent. (3) Yarn coating and drying: The Artemisia argyi yarn is immersed in a coating solution containing a photoinitiator and a crosslinking agent, or the coating solution is uniformly coated onto the surface of the Artemisia argyi yarn, and then dried at room temperature in a ventilated place to remove the dichloromethane solvent, thus obtaining a dry coated yarn. (4) Ultraviolet crosslinking treatment: The dried coated yarn is subjected to cross-linking treatment by irradiating it under ultraviolet light for 20 minutes. Benzophenone and triallyl isocyanurate are then subjected to free radical polymerization in a mixture of polycaprolactone and polyethylene glycol to form a three-dimensional network structure coated yarn, thus obtaining a thermally responsive shape memory coated yarn. Step 2: Preparation of wet-response modified wool yarn: (1) Preparation of sodium hypochlorite chlorination reaction solution: Add 6-12 mL of 5% sodium hypochlorite solution to deionized water and bring the volume up to 50 mL. Then add 0.5 g of nano calcium carbonate and 0.13 mL of hydrochloric acid. Stir at room temperature for 30 min until uniformly dispersed to obtain sodium hypochlorite chlorination reaction solutions of different concentrations. (2) Ultrasonic chlorination treatment: The wool yarn was completely immersed in sodium hypochlorite chlorination reaction solution and placed in an ultrasonic cleaner for 30-60 minutes at a frequency of 35kHz and a power of 40W. (3) Washing and drying: The wool yarn after ultrasonic chlorination treatment is taken out, washed with deionized water until neutral, and dried in an oven at 50°C to obtain wet-response modified wool yarn. Step 3: Prepare a heat and moisture dual-response smart knitted fabric: (1) Fabric base for weaving: Using a computerized flat knitting machine, wet-responsive modified wool yarn and artemisia yarn are interwoven to weave a fabric base with an open air layer structure. The number of open needles is 12, 16, 20 or 24. The wet-responsive modified wool yarn is used to weave the surface layer and the artemisia yarn is used to weave the bottom layer. (2) Embedded thermally responsive shape memory coated yarn: By inserting heat-responsive shape memory coated yarn from the reverse loop of wet-responsive modified wool yarn into the internal structure of the fabric in a way that alternates between 1 or 2 loops, a heat- and moisture-responsive smart knitted fabric is obtained.

4. The method for preparing a heat and moisture dual-response smart knitted fabric according to claim 3, characterized in that: In step 1, the mass ratio of polycaprolactone to polyethylene glycol is 8:2, and the total amount of benzophenone and triallyl isocyanurate added is 5 wt%.

5. The method for preparing a heat and moisture dual-response smart knitted fabric according to claim 3, characterized in that: In step 2, the amount of sodium hypochlorite chlorination reaction solution added is 10 mL, and the ultrasonic treatment time is 40 min.

6. The method for preparing a heat and moisture dual-response smart knitted fabric according to claim 3, characterized in that: In step 3, the number of opening needles in the air layer opening structure is 20, and the embedding method is longitudinal, with 2 needles inserted every other needle.

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