Preparation method of traditional Chinese medicine-nanocellulose composite tensile fiber fabric

Abstract

The invention relates to the technical field of functional polymer materials, in particular to a preparation method of a traditional Chinese medicine-nanocellulose composite tensile fiber fabric, which comprises the following steps: firstly, carrying out gradient functionalization treatment on nanocellulose, and grafting GMA (glycidyl methacrylate) and NIPAM (N-isopropylacrylamide); then preparing a traditional Chinese medicine microcapsule, extracting a Sanhuang compound, taking chitosan and sodium alginate as wall materials, and adopting a pH / temperature double-response cross-linking system; then blending the functionalized nanocellulose, the traditional Chinese medicine microcapsules and the oxidized starch with a PBAT solution to construct a composite material; directionally freezing the composite system on a temperature gradient device, and then freeze-drying to form a multi-stage directional pore channel structure; carrying out hot pressing treatment under the conditions of 60 to 70 DEG C and 1.5 to 2.5 MPa; finally, silanization surface hydrophobization, soft finishing and shaping treatment are conducted, the traditional Chinese medicine-nanocellulose composite tensile fiber fabric is obtained, and dual responses to sweat pH changes and body temperature rising are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of functional polymer materials, specifically to a preparation method of a traditional Chinese medicine-nanocellulose composite tensile fiber fabric, especially a bio-based composite fiber material with persistent antibacterial properties, excellent air permeability and quick drying, and enhanced mechanical properties. Background Art

[0002] With the continuous improvement of people's requirements for functional textiles, fiber fabrics with multiple functions integrated such as antibacterial, air permeable and quick drying, comfortable and durable are becoming increasingly popular in the market. Traditional antibacterial fabrics mainly use metal ions (such as silver and copper) or quaternary ammonium salt antibacterial agents. Although they have certain antibacterial effects, they have problems such as poor antibacterial persistence, low environmental friendliness, and easy induction of bacterial drug resistance. The air permeable and quick drying fabrics mainly achieve the moisture management function through special fiber structure design, but it is often difficult to be compatible with the antibacterial function. In addition, while improving comfort, functional fabrics often have insufficient mechanical properties and short service life, which limits their application in high-performance fields.

[0003] US Patent US7737056B2 discloses a breathable and quick-drying fabric, which includes an outer layer and an inner layer. The outer layer is made of hydrophilic synthetic fibers and has multiple pores, and the inner layer is made of hydrophobic synthetic fibers and is combined with the outer layer. When sweating exceeds the evaporation rate of the outer layer, the part of the inner layer exposed in the pores will move away from the human skin and protrude into the pores, thereby reducing the contact area between the inner layer and the skin. However, although this technology has a certain breathable and quick-drying effect, it lacks antibacterial function and relies on synthetic fibers, with insufficient environmental friendliness.

[0004] Russian Patent RU2524635C2 discloses a medical device using a traditional Chinese medicine preparation as an antibacterial coating. The antibacterial composition includes a material capable of forming a polymer film and an antibacterial preparation from traditional Chinese medicine. This technology applies the antibacterial activity of traditional Chinese medicine to the surface of medical devices, but does not organically combine it with the internal structure of fiber materials, making it difficult to achieve a persistent antibacterial effect and lacking air permeability and quick drying functions.

[0005] US Patent US20080241530A1 discloses an antibacterial, antifungal and antiviral polymer material, which consists of rayon fibers and a single antibacterial component. This technology mainly relies on copper oxide particles to provide antibacterial function, has potential environmental and health risks of metal ions, and cannot achieve an intelligent response antibacterial function.

[0006] In recent years, as a renewable bio-based material, nanocellulose has received extensive attention in the field of high-performance composite materials due to its excellent mechanical properties, high specific surface area, and good biocompatibility. At the same time, traditional Chinese medicine extracts, with their safe, broad-spectrum, and multi-target antibacterial characteristics, provide new ideas for solving the limitations of synthetic antibacterial agents. However, how to effectively combine nanocellulose with traditional Chinese medicine extracts to simultaneously achieve the synergistic enhancement of antibacterial, breathable and quick-drying, and mechanical properties remains a technical challenge to be solved urgently. Summary of the Invention

[0007] The object of the present invention is to provide a preparation method of a traditional Chinese medicine-nanocellulose composite tensile fiber fabric, to solve the technical problems of poor breathability, non-persistent antibacterial effect, and insufficient mechanical properties existing in existing antibacterial fabrics, and to achieve the synergistic enhancement of antibacterial, breathable and quick-drying, and mechanical properties.

[0008] To achieve the above object, the present invention provides a preparation method of a traditional Chinese medicine-nanocellulose composite tensile fiber fabric, including the following steps:

[0009] (1) Gradient functionalization treatment of nanocellulose: In the presence of an initiator, graft glycidyl methacrylate (GMA) and N-isopropylacrylamide (NIPAM) onto the nanocellulose aqueous dispersion in sequence to form nanocellulose with gradient functionalization on the surface;

[0010] (2) Preparation of traditional Chinese medicine microcapsules: Extract Coptis chinensis, Scutellaria baicalensis, and Phellodendron amurense in a weight ratio of 1-3:0.5-1.5:0.5-1.5 to obtain a three-yellow composite extract, and use chitosan and sodium alginate as wall materials to prepare microcapsules by a pH / temperature dual-responsive cross-linking system;

[0011] (3) Construction of the composite material: Mix the functionalized nanocellulose, traditional Chinese medicine microcapsules, and oxidized starch, and blend them with a poly(butylene adipate-co-butylene terephthalate) (PBAT) solution to form a composite system;

[0012] (4) Formation of a hierarchical pore structure: Directionally freeze the composite system on a device with a temperature gradient, and then perform freeze-drying treatment to form a composite material with a hierarchical directional pore structure;

[0013] (5) Hot pressing treatment: Perform hot pressing densification treatment at 60-70 °C and 1.5-2.5 MPa;

[0014] (6) Surface functionalization: Perform surface hydrophobization by silanization treatment, and then perform soft finishing and shaping treatment to obtain a traditional Chinese medicine-nanocellulose composite tensile fiber fabric.

[0015] Preferably, the specific steps of the gradient functionalization treatment of nanocellulose in step (1) include:

[0016] Under nitrogen protection, an aqueous nanofibrillated cellulose dispersion (1.5 - 2.5 wt%) was first added dropwise with GMA (15 - 25% of the weight of nanofibrillated cellulose) at 65 - 75 °C using ammonium persulfate (APS) as an initiator and reacted for 2.5 - 3.5 hours. Then, NIPAM (10 - 20% of the weight of GMA) was added and reacted for 0.5 - 1.5 hours. After terminating the reaction, it was washed and redispersed to a solid content of 2 - 3 wt%.

[0017] Preferably, the preparation method of the Sanhuang composite extract in step (2) is as follows:

[0018] Coptis chinensis was reflux-extracted with 55 - 65% ethanol (75 - 85 °C, 2.5 - 3.5 hours, solid-liquid ratio 1:8 - 12);

[0019] Scutellaria baicalensis was ultrasonically assisted-extracted with 65 - 75% ethanol (55 - 65 °C, 1.5 - 2.5 hours, 250 - 350 W);

[0020] Phellodendron amurense was microwave-assisted-extracted with 45 - 55% ethanol (65 - 75 °C, 25 - 35 minutes, 450 - 550 W);

[0021] Each extract was concentrated under reduced pressure, precipitated with ethanol, dried and powdered, and then mixed in proportion to obtain the composite extract.

[0022] Preferably, the specific steps for preparing the microcapsules in step (2) are as follows:

[0023] The Sanhuang composite extract (2.5 - 3.5% w / v) was dispersed in a chitosan solution (1.5 - 2.5% w / v), NIPAM-grafted nanoshell chitosan (0.3 - 0.7% w / v) was added, and it was added dropwise into a sodium alginate solution (1.0 - 2.0% w / v) at a rate of 2 - 4 mL / min, stirred (600 - 800 rpm, 25 - 35 minutes), glutaraldehyde solution (0.3 - 0.7% v / v) was added for crosslinking for 5 - 15 minutes, the pH was adjusted to 7.0 - 7.5, and then centrifuged, washed, and freeze-dried to obtain the microcapsules.

[0024] Preferably, the specific steps for constructing the composite material in step (3) are as follows:

[0025] To a functionalized nanofibrillated cellulose dispersion (1.5 - 2.5% w / v), oxidized starch (0.3 - 0.7% of the weight of cellulose) was added, stirred at 30 - 40 °C for 30 - 50 minutes, a microcapsule suspension (0.8 - 1.2% w / v) was added, stirred at room temperature for 1.5 - 2.5 hours, intermittently ultrasonically assisted for dispersion, homogenized by high-speed stirring for 20 - 40 minutes, and refrigerated and allowed to stand for 8 - 16 hours to form a stable composite system.

[0026] Preferably, the specific steps of blending PBAT with the composite material in step (3) are as follows:

[0027] PBAT is dissolved in chloroform to form a 6 - 8% w / v solution, Span - 80 (1.0 - 2.0% of the weight of PBAT) is added as an emulsifier, the volume ratio of the aqueous phase to the organic phase is 2.5 - 3.5:1. The PBAT solution is slowly added to the nano - cellulose - microcapsule aqueous dispersion system, and high - speed stirring (700 - 900 rpm) is carried out to form a stable emulsion, followed by intermittent ultrasonic treatment for 4 - 6 minutes, and partial solvent is evaporated under reduced pressure until the solid content is 4 - 6%.

[0028] Preferably, the specific steps of directional freezing in step (4) are as follows:

[0029] A temperature gradient device with bottom refrigeration (-75 to -85 °C) and top insulation at room temperature is used, the temperature gradient is 12 - 22 °C / cm. The composite material suspension (1.0 - 1.5% w / v) is poured into a mold to a thickness of 6 - 10 mm, placed on the temperature gradient device, and the cooling rate (1.5 - 2.5 °C / min) is controlled to form a directional ice crystal structure, and the environment of -75 to -85 °C is maintained for 5 - 7 hours.

[0030] Preferably, the specific parameters of freeze - drying treatment in step (4) are as follows:

[0031] The initial temperature is -45 to -55 °C, the vacuum degree is 0.005 - 0.06 mbar, the heating program is to raise the temperature to 5 - 15 °C at a rate of 0.3 - 0.7 °C / h, the total freeze - drying time is 50 - 70 hours, and the temperature is reduced to room temperature before the vacuum is released after freeze - drying is completed.

[0032] Preferably, the specific steps of surface functionalization in step (6) are as follows:

[0033] The material is first vacuum - dried at 65 - 75 °C for 3 - 5 hours, then immersed in octadecyltrimethoxysilane (ODTMS) (1.5 - 2.5% v / v toluene solution), reacted at 80 - 90 °C for 4 - 6 hours under nitrogen protection, washed with toluene 2 - 4 times, washed with absolute ethanol 1 - 3 times, and vacuum - dried at 65 - 75 °C for 5 - 7 hours; then impregnated in an aqueous solution of silicone softener (1.5 - 2.5% w / v) at 35 - 45 °C for 25 - 35 minutes, the squeezing - out rate is 75 - 85%, dried in an oven (75 - 85 °C, 12 - 18 minutes), heat - set (105 - 115 °C, 1 - 3 minutes), and cooled to room temperature.

[0034] Preferably, the prepared traditional Chinese medicine - nano - cellulose composite tensile fiber fabric is used to prepare sportswear, medical protective clothing, outdoor equipment, close - fitting underwear or functional home textile products.

[0035] The beneficial effects of the present invention are:

[0036] 1. The innovative nano - cellulose gradient functionalization technology realizes the functional gradient distribution from the inside to the outside of the nano - cellulose surface by precisely controlling the grafting process of glycidyl methacrylate (GMA) and N - isopropylacrylamide (NIPAM). It retains the mechanical strength of the internal crystalline region, and at the same time introduces reactive functional groups and thermosensitive response characteristics on the surface, providing a basis for subsequent functionalization and compounding.

[0037] 2. The unique pH / temperature dual - responsive microcapsule technology of traditional Chinese medicine Sanhuang extract forms a broad - spectrum antibacterial system by synergistically combining the effective components of Coptis chinensis, Scutellaria baicalensis, and Phellodendron amurense. Using chitosan - sodium alginate composite wall materials and a thermosensitive cross - linked network, it realizes the dual response to the pH change of sweat and the increase in body temperature, achieving the intelligent antibacterial effect of "releasing on demand" and significantly improving the antibacterial persistence.

[0038] 3. The multi - level directional pore structure design forms a multi - level water transport channel from the nano - scale to the micro - scale and then to the macro - scale by controlling the directional freezing - freeze - drying process, establishing an efficient "unidirectional pump effect", enabling sweat to quickly migrate from the skin side to the external environment, and still maintaining excellent air permeability and quick - drying performance even in a high - humidity environment.

[0039] 4. The oxidation starch cross - linked interface synergistic technology effectively solves the interfacial compatibility problem between nano - cellulose and the PBAT matrix. Through multiple chemical bonds and physical entanglement, it significantly improves the interfacial bonding strength, realizes the synergistic enhancement of mechanical properties, and provides excellent tensile strength while maintaining good flexibility.

[0040] 5. The design of all - biobased raw materials avoids the environmental risks of traditional metal antibacterial agents, meets the requirements of green and sustainable development, and has good biocompatibility and degradability.

[0041] In summary, through the organic combination of three innovative points: nano - cellulose gradient functionalization, traditional Chinese medicine microcapsule controlled - release technology, and multi - level pore structure design, the present invention realizes the synergistic enhancement of antibacterial, air permeability and quick - drying, and mechanical properties, overcomes multiple technical bottlenecks of traditional antibacterial fabrics, and has significant technological innovation and application value. Detailed implementation manners

[0042] The present invention will be further described in detail below in combination with specific embodiments, but the protection scope of the present invention is not limited thereto.

[0043] Raw materials and reagents:

[0044] Nano - cellulose: with a diameter of 5 - 50 nm, a length of 500 - 2000 nm, and a crystallinity of 54 - 88%, purchased from Nanjing Senu New Materials Technology Co., Ltd.;

[0045] Poly(butylene adipate-co-butylene terephthalate) (PBAT): number average molecular weight 35,000 - 45,000, purchased from BASF;

[0046] Glycidyl methacrylate (GMA): purity ≥ 98%, purchased from Aladdin Reagent Co., Ltd.;

[0047] N-Isopropylacrylamide (NIPAM): purity ≥ 99%, purchased from Sigma-Aldrich;

[0048] Ammonium persulfate (APS): analytical reagent grade, purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0049] Chitosan: degree of deacetylation > 80%, viscosity 100 - 300 mPa·s, purchased from Qingdao Baotai Biotechnology Co., Ltd.;

[0050] Sodium alginate: viscosity 300 - 500 mPa·s, purchased from Cargill;

[0051] Oxidized starch: carboxyl content 8 - 12%, purchased from Shandong Longli Biotechnology Co., Ltd.;

[0052] Octadecyltrimethoxysilane (ODTMS): purity ≥ 95%, purchased from Aladdin Reagent Co., Ltd.;

[0053] Coptis chinensis, Scutellaria baicalensis, Phellodendron amurense: pharmaceutical grade, purchased from Beijing Tongrentang Chinese Herbal Medicine Co., Ltd.;

[0054] Other reagents are all of analytical reagent grade.

[0055] Example 1

[0056] Preparation method of traditional Chinese medicine-nanocellulose composite tensile fiber fabric, comprising the following steps:

[0057] (1) Nanocellulose gradient functionalization treatment:

[0058] Purify 500 mL of nanocellulose aqueous dispersion (2.0 wt%) three times by centrifugation (6000 rpm, 15 minutes), then perform dialysis treatment for 48 hours and change water six times. Ultrasonically treat the purified nanocellulose dispersion in an ice bath (20 kHz, 250 W) for 30 minutes with intermittent operation (on for 30 seconds, off for 10 seconds), and then adjust the pH to 5.0 (using 0.1 M acetate buffer). Transfer the treated nanocellulose dispersion to a 1 L double-jacketed glass reactor, and introduce nitrogen for 30 minutes to remove dissolved oxygen. Raise the reactor temperature to 70 °C, dissolve 20.0 g of GMA (20% of the weight of nanocellulose) in 50 mL of deionized water, and slowly add it dropwise to the reaction system within 40 minutes. Subsequently, add a solution of 0.8 g of APS dissolved in 20 mL of water, and then add a solution of 0.3 g of TEMED dissolved in 10 mL of water in two portions (the second portion is added after 30 minutes). After reacting for 3 hours, add 3.0 g of NIPAM (15% of the weight of GMA) solution and continue reacting for 1 hour. Finally, add 0.023 g of hydroquinone to terminate the reaction. Dilute the reaction system two-fold with deionized water, separate the product by centrifugation (4000 rpm, 15 minutes), wash it three times with deionized water and twice with ethanol, and redisperse it in deionized water to adjust the solid content to 2.0 wt%.

[0059] (2) Preparation of traditional Chinese medicine microcapsules:

[0060] Extraction of Coptis chinensis: Weigh 50 g of Coptis chinensis medicinal materials, crush them through an 80-mesh sieve, add 500 mL of 60% ethanol, and reflux and extract at 80 °C for 3 hours. Filter, collect the filtrate, and concentrate it under reduced pressure to a relative density of 1.12. Add 95% ethanol for precipitation according to the ratio of extract:ethanol = 1:2, let it stand for 12 hours, filter, and dry it under reduced pressure at 50 °C to obtain the Coptis chinensis extract.

[0061] Extraction of Scutellaria baicalensis: Weigh 25 g of Scutellaria baicalensis medicinal materials, crush them through an 80-mesh sieve, add 250 mL of 70% ethanol, and perform ultrasonic-assisted extraction (300 W) at 60 °C for 2 hours. The subsequent treatment is the same as that for the extraction of Coptis chinensis to obtain the Scutellaria baicalensis extract.

[0062] Extraction of Phellodendron amurense: Weigh 25 g of Phellodendron amurense medicinal materials, crush them through an 80-mesh sieve, add 250 mL of 50% ethanol, and perform microwave-assisted extraction (500 W) at 70 °C for 30 minutes. The subsequent treatment is the same as that for the extraction of Coptis chinensis to obtain the Phellodendron amurense extract.

[0063] The extracts of Rhizoma Coptidis, Radix Scutellariae, and Rhizoma Phellodendri were mixed in a weight ratio of 2:1:1 to prepare the compound extract of Rhizoma Coptidis. Weigh 3.0g of the compound extract of Rhizoma Coptidis, disperse it in 100mL of chitosan solution (2.0% w / v, dissolved in 1% acetic acid solution), and ultrasonically disperse it for 15 minutes. Add 0.5g of NIPAM grafted nano-chitosan (0.5% w / v) as a temperature-sensitive component and stir it magnetically for 30 minutes. The mixed solution was added dropwise to 150mL of sodium alginate solution (1.5% w / v) at a rate of 2.5mL / min, and stirred (700rpm, 30 minutes) to form initial microcapsules. Slowly add 10mL of glutaraldehyde solution (0.5% v / v) for cross-linking for 10 minutes, and then adjust the pH to 7.2 to stabilize the microcapsule structure. Centrifuge (3000rpm, 10 minutes), wash with water 3 times, freeze at -40℃ for 2 hours, and then freeze-dry for 48 hours to obtain microcapsule powder.

[0064] (3) Composite material construction:

[0065] Weigh 200 mL of functionalized nanocellulose dispersion (2.0% w / v), add oxidized starch (0.5% of the weight of cellulose, i.e. 0.2 g), and stir at 35°C for 40 minutes. Then slowly add 100 mL of microcapsule suspension (1.0% w / v) and stir at room temperature for 2 hours. Ultrasonic treatment for 1 minute (power 100 W) every 30 minutes, followed by high-speed stirring (500 rpm) for 30 minutes, and refrigerate for 12 hours to form a stable composite system.

[0066] At the same time, 7.0g PBAT was dissolved in 100mL chloroform to prepare a 7% w / v solution, and 1.5% Span-80 (i.e. 0.105g) was added as an emulsifier. The PBAT solution was slowly added to the nanocellulose-microcapsule aqueous dispersion system (the volume ratio of the aqueous phase: organic phase was 3:1), and a stable emulsion was formed by high-speed stirring (800rpm) for 15 minutes, and ultrasonic treatment was performed for 5 minutes (intermittently, 30 seconds on and 10 seconds off). Subsequently, part of the solvent was evaporated under reduced pressure in a 40°C water bath and concentrated to a solid content of about 5%.

[0067] (4) Formation of multi-level pore structure:

[0068] A temperature gradient device with a bottom of -80°C and a top of room temperature was designed to form a temperature gradient of about 18°C / cm. The composite suspension (1.2% w / v) was poured into a mold with a thickness of 8mm and placed on the temperature gradient device with the bottom contacting the freezing platform. The cooling rate was controlled to 2°C / min to form a directional ice crystal structure, and the -80°C environment was maintained for 6 hours to ensure complete freezing.

[0069] Place the frozen sample on the pre-cooled condensation plate of the freeze dryer. The initial temperature is -50°C, the vacuum degree is 0.03 mbar, and it is gradually heated to 10°C at a rate of 0.5°C / h. The total freeze-drying time is 60 hours. After freeze-drying is completed, it is cooled to room temperature before vacuum is released.

[0070] (5) Hot pressing treatment:

[0071] Place the freeze-dried sample in a mold, preheat the pressing plate to 65°C, apply a pressure of 2.0 MPa, hold for 12 minutes, cool to room temperature under pressure, and demold to obtain a multi-porous structure oriented fiber material.

[0072] (6) Surface functionalization:

[0073] Dry the material in vacuum at 70°C for 4 hours, then immerse it in a solution of 2% v / v octadecyltrimethoxysilane (ODTMS) dissolved in anhydrous toluene, and react at 85°C for 5 hours under nitrogen protection. After the reaction is completed, wash it 3 times with toluene and 2 times with absolute ethanol, and dry it in vacuum at 70°C for 6 hours.

[0074] Subsequently, immerse the material in an aqueous solution of silicone softener (2% w / v), impregnate it at 40°C for 30 minutes, and control the liquor ratio to 80%. Dry it in an oven at 80°C for 15 minutes, then thermally set it at 110°C for 2 minutes, and finally cool it naturally at room temperature to obtain the finished traditional Chinese medicine-nanocellulose composite tensile fiber fabric.

[0075] Example 2

[0076] A preparation method of a traditional Chinese medicine-nanocellulose composite tensile fiber fabric, comprising the following steps:

[0077] (1) Nanocellulose gradient functionalization treatment:

[0078] After 500 mL of nanocellulose aqueous dispersion (1.5 wt%) undergoes the same pretreatment as in Example 1, it is heated to 65°C under nitrogen protection. Dissolve 15.0 g of GMA (20% of the weight of nanocellulose) in 40 mL of deionized water, and slowly add it dropwise to the reaction system within 45 minutes. Subsequently, add a solution of 0.6 g of APS dissolved in 15 mL of water, and then add a solution of 0.25 g of TEMED dissolved in 8 mL of water in two portions. After reacting for 3.5 hours, add 1.5 g of NIPAM (10% of the weight of GMA) solution, and continue to react for 0.5 hours. Finally, add 0.017 g of hydroquinone to terminate the reaction. The subsequent treatment is the same as in Example 1, and finally the solid content is adjusted to 2.0 wt%.

[0079] (2) Preparation of traditional Chinese medicine microcapsules:

[0080] Coptis chinensis extraction: Weigh 60 g of Coptis chinensis medicinal materials, crush them through an 80-mesh sieve, add 600 mL of 55% ethanol, and reflux and extract at 75 °C for 3.5 hours. The subsequent treatment is the same as that in Example 1 to obtain the Coptis chinensis extract.

[0081] Scutellaria baicalensis extraction: Weigh 20 g of Scutellaria baicalensis medicinal materials, crush them through an 80-mesh sieve, add 200 mL of 75% ethanol, and perform ultrasonic-assisted extraction (250 W) at 55 °C for 2.5 hours. The subsequent treatment is the same as that in Example 1 to obtain the Scutellaria baicalensis extract.

[0082] Phellodendron amurense extraction: Weigh 20 g of Phellodendron amurense medicinal materials, crush them through an 80-mesh sieve, add 200 mL of 45% ethanol, and perform microwave-assisted extraction (450 W) at 65 °C for 35 minutes. The subsequent treatment is the same as that in Example 1 to obtain the Phellodendron amurense extract.

[0083] Mix the Coptis chinensis, Scutellaria baicalensis, and Phellodendron amurense extracts according to a weight ratio of 3:1:1 to prepare a Sanhuang composite extract. Weigh 3.5 g of the Sanhuang composite extract and disperse it in 100 mL of a chitosan solution (2.5% w / v). The subsequent steps are the same as those in Example 1, but the sodium alginate concentration is adjusted to 2.0% w / v and the glutaraldehyde concentration is adjusted to 0.7% v / v.

[0084] (3) Composite material construction:

[0085] Weigh 200 mL of a functionalized nanocellulose dispersion (2.5% w / v), add oxidized starch (0.7% of the cellulose weight, i.e., 0.35 g). The remaining steps are the same as those in Example 1, but the PBAT concentration is adjusted to 8% w / v and the Span-80 dosage is adjusted to 2.0% of the PBAT weight.

[0086] (4) Formation of hierarchical pore structure:

[0087] Adjust the temperature gradient to 15 °C / cm, the concentration of the composite material suspension to 1.0% w / v, the thickness to 10 mm, the cooling rate to 1.5 °C / min, and the initial freeze-drying temperature to -45 °C. The remaining parameters are the same as those in Example 1.

[0088] (5) Hot pressing treatment:

[0089] Adjust the hot pressing temperature to 70 °C, the pressure to 1.5 MPa, and the holding time to 15 minutes. The rest is the same as that in Example 1.

[0090] (6) Surface functionalization:

[0091] Adjust the ODTMS concentration to 1.5% v / v, the reaction temperature to 80 °C, the reaction time to 4 hours, and the concentration of the silicone softener to 1.5% w / v. The rest is the same as that in Example 1.

[0092] Example 3

[0093] Preparation method of traditional Chinese medicine-nanocellulose composite tensile fiber fabric, comprising the following steps:

[0094] (1) Gradient functionalization treatment of nanocellulose:

[0095] After pretreatment of 500 mL of nanocellulose aqueous dispersion (2.5 wt%), the temperature is raised to 75 °C under nitrogen protection. 25.0 g of GMA (20% of the weight of nanocellulose) is dissolved in 60 mL of deionized water and slowly added dropwise to the reaction system within 30 minutes. Subsequently, a solution of 1.0 g of APS dissolved in 25 mL of water is added, and then a solution of 0.35 g of TEMED dissolved in 12 mL of water is added in two portions. After reacting for 2.5 hours, a solution of 5.0 g of NIPAM (20% of the weight of GMA) is added, and the reaction continues for 1.5 hours. Finally, 0.03 g of hydroquinone is added to terminate the reaction. The subsequent treatment is the same as in Example 1, and the solid content is finally adjusted to 3.0 wt%.

[0096] (2) Preparation of traditional Chinese medicine microcapsules:

[0097] Extraction of Coptis chinensis: Weigh 40 g of Coptis chinensis medicinal materials, add 400 mL of 65% ethanol, and reflux extract at 85 °C for 2.5 hours.

[0098] Extraction of Scutellaria baicalensis: Weigh 30 g of Scutellaria baicalensis medicinal materials, add 300 mL of 65% ethanol, and perform ultrasonic-assisted extraction (350 W) at 65 °C for 1.5 hours.

[0099] Extraction of Phellodendron amurense: Weigh 30 g of Phellodendron amurense medicinal materials, add 300 mL of 55% ethanol, and perform microwave-assisted extraction (550 W) at 75 °C for 25 minutes.

[0100] The subsequent treatment is the same as in Example 1. The three extracts are mixed in a weight ratio of 1:0.5:0.5 to obtain a three-yellow composite extract. During the microcapsule preparation process, the amount of the three-yellow composite extract is 2.5 g, the chitosan concentration is 1.5% w / v, the sodium alginate concentration is 1.0% w / v, and the glutaraldehyde concentration is 0.3% v / v.

[0101] (3) Construction of composite materials:

[0102] Weigh 200 mL of functionalized nanocellulose dispersion (1.5% w / v), add oxidized starch (0.3% of the weight of cellulose, i.e., 0.09 g), and the remaining steps are the same as in Example 1, but the PBAT concentration is adjusted to 6% w / v and the Span-80 dosage is adjusted to 1.0% of the weight of PBAT.

[0103] (4) Formation of hierarchical pore structure:

[0104] Adjust the temperature gradient to 22 °C / cm, the concentration of the composite suspension to 1.5% w / v, the thickness to 6 mm, the cooling rate to 2.5 °C / min, and the initial freeze-drying temperature to -55 °C. The other parameters are the same as in Example 1.

[0105] (5) Hot pressing treatment:

[0106] Adjust the hot pressing temperature to 60 °C, the pressure to 2.5 MPa, and the holding time to 10 minutes. The other conditions are the same as in Example 1.

[0107] (6) Surface functionalization:

[0108] Adjust the concentration of ODTMS to 2.5% v / v, the reaction temperature to 90 °C, the reaction time to 6 hours, and the concentration of the silicone softener to 2.5% w / v. The other conditions are the same as in Example 1.

[0109] Example 4

[0110] A method for preparing a traditional Chinese medicine-nanocellulose composite tensile fiber fabric, comprising the following steps:

[0111] (1) Nanocellulose gradient functionalization treatment:

[0112] It is basically the same as Example 2, but the dosage of GMA is adjusted to 25% of the weight of nanocellulose, and the dosage of NIPAM is adjusted to 18% of the weight of GMA.

[0113] (2) Preparation of traditional Chinese medicine microcapsules:

[0114] It is basically the same as Example 3, but the ratio of the Sanhuang extract is adjusted to Coptis chinensis: Scutellaria baicalensis: Phellodendron amurense = 1.5:1:1, and 0.2% w / v of sodium carboxymethylcellulose is added as a reinforcing agent in the microcapsule wall material.

[0115] (3) Composite material construction:

[0116] It is basically the same as Example 1, but the dosage of oxidized starch is adjusted to 0.4% of the weight of cellulose, and 0.1% of citric acid is added as a crosslinking agent.

[0117] (4) Formation of hierarchical pore structure:

[0118] It is basically the same as Example 2, but the heating rate during freeze-drying is adjusted to 0.4 °C / h, and the total freeze-drying time is extended to 70 hours.

[0119] (5) Hot pressing treatment:

[0120] Adjust the hot pressing temperature to 67 °C, the pressure to 2.2 MPa, and the holding time to 14 minutes.

[0121] (6) Surface functionalization:

[0122] It is basically the same as Example 3, but after silanization, an additional ultraviolet light irradiation treatment (254 nm, 10 minutes) is added to enhance the cross-linking effect.

[0123] Example 5

[0124] A preparation method of a traditional Chinese medicine-nanocellulose composite tensile fiber fabric, comprising the following steps:

[0125] (1) Nanocellulose gradient functionalization treatment:

[0126] It is basically the same as Example 1, but KPS is used as the initiator, and the dosage is 80% of APS, and the reaction temperature is adjusted to 68 °C.

[0127] (2) Preparation of traditional Chinese medicine microcapsules:

[0128] It is basically the same as Example 1, but the extraction of the three traditional Chinese medicines is changed to the supercritical CO extraction technology, and the extraction time is shortened to 1.5 hours each, and the ratio of the extracts of Coptis chinensis: Scutellaria baicalensis: Phellodendron amurense is adjusted to 2:1.5:0.5.

[0129] (3) Composite material construction:

[0130] It is basically the same as Example 2, but PBAT is replaced by polylactic acid (PLA) with a concentration of 7.5% w / v, and 0.2% of cellulose acetate is added as a toughening agent.

[0131] (4) Formation of a hierarchical pore structure:

[0132] It is basically the same as Example 3, but an ultrasonic field assistance (20 kHz, 15 minutes) is introduced during the freezing process to optimize the ice crystal growth direction.

[0133] (5) Hot pressing treatment:

[0134] The hot pressing temperature is adjusted to 63 °C, the pressure is adjusted to 1.8 MPa, and the holding time is 13 minutes.

[0135] (6) Surface functionalization:

[0136] It is basically the same as Example 1, but after silanization, an additional plasma treatment (oxygen plasma, 50 W, 5 minutes) is added to improve the surface hydrophilicity gradient.

[0137] Example 6

[0138] A preparation method of a traditional Chinese medicine-nanocellulose composite tensile fiber fabric, comprising the following steps:

[0139] (1) Nanocellulose gradient functionalization treatment:

[0140] Basically the same as Example 3, but after grafting NIPAM, acrylic acid (5% of the weight of nanocellulose) was additionally grafted and reacted for 1 hour to provide additional carboxyl functional points.

[0141] (2) Preparation of traditional Chinese medicine microcapsules:

[0142] Basically the same as Example 2, but 5% of green tea extract was additionally added to the Sanhuang composite extract as an antioxidant synergistic component, and 1% of gelatin was added to the microcapsule wall material as a toughening component.

[0143] (3) Construction of composite materials:

[0144] Basically the same as Example 1, but epoxidized soybean oil (2% of the weight of nanocellulose) was used as a plasticizer, and 0.3% of lauric acid was added as a dispersion aid.

[0145] (4) Formation of hierarchical pore structure:

[0146] Basically the same as Example 4, but the dispersion was subjected to shear pretreatment (5000 rpm, 2 minutes) before freezing to improve the dispersion uniformity.

[0147] (5) Hot pressing treatment:

[0148] The hot pressing was carried out in a stepwise pressure mode. The initial pressure of 1.0 MPa was maintained for 5 minutes, then increased to 2.0 MPa and maintained for 10 minutes, and the temperature was maintained at 65 °C.

[0149] (6) Surface functionalization:

[0150] Basically the same as Example 2, but vinyltrimethoxysilane was used to replace ODTMS, and ultraviolet light-induced crosslinking (365 nm, 20 minutes) was carried out after the reaction to improve the surface wear resistance.

[0151] Comparative Example 1 (without nanocellulose functionalization treatment)

[0152] A method for preparing a traditional Chinese medicine-nanocellulose composite tensile fiber fabric, the steps are basically the same as those in Example 1, but the grafting process of GMA and NIPAM in step (1) is omitted, and unfunctionalized nanocellulose is directly used for subsequent composite. Specifically, the nanocellulose aqueous dispersion (2.0 wt%) was only subjected to ultrasonic treatment and pH adjustment, without functionalization grafting, and then directly used for the construction of composite materials in step (3). The remaining steps are the same as those in Example 1.

[0153] Comparative Example 2 (without traditional Chinese medicine microcapsules)

[0154] A preparation method of a nano - cellulose composite tensile fiber fabric, the steps are basically the same as those in Example 1, but the preparation process of the traditional Chinese medicine microcapsules in step (2) is omitted, and functionalized nano - cellulose and PBAT are directly used for blending in the composite material construction in step (3) without adding traditional Chinese medicine components. The remaining steps are the same as those in Example 1.

[0155] Comparative Example 3 (without directional freezing structure design)

[0156] A preparation method of a traditional Chinese medicine - nano - cellulose composite tensile fiber fabric, the steps are basically the same as those in Example 1, but in step (4), the temperature - gradient directional freezing technology is not used and is changed to conventional freezing (-20 °C refrigerator for 24 hours), resulting in the inability to form a directional multi - pore structure. The remaining steps are the same as those in Example 1.

[0157] In order to evaluate the performance of the prepared traditional Chinese medicine - nano - cellulose composite tensile fiber fabric, a series of standard tests were carried out, mainly including mechanical properties, antibacterial properties, and moisture management properties, etc.

[0158] 1. Mechanical property test

[0159] According to the GB / T1040.3 - 2006 standard, a universal material testing machine (model: Instron5967) was used to measure the tensile strength, elongation at break, and Young's modulus of the samples. The test conditions were: temperature 23 ± 2 °C, relative humidity 50 ± 5%, tensile rate 20 mm / min, and the specimen size was 150 mm × 10 mm × 0.5 mm. Each sample was tested 5 times and the average value was taken.

[0160] 2. Antibacterial property test

[0161] Adopting the standard method of GB / T20944.3 - 2008, Staphylococcus aureus (ATCC6538) and Escherichia coli (ATCC8099) were selected as test strains to evaluate the antibacterial activity of the samples. The samples were cut into 1.5 cm × 1.5 cm specifications, sterilized by ultraviolet for 30 minutes, then contacted with the bacterial suspension (1 × 10 CFU / mL), and samples were taken at 0, 4, 8, 12, and 24 hours respectively, and the dilution plate counting was carried out to calculate the antibacterial rate. At the same time, the samples were washed repeatedly according to the standard (GB / T8629 - 2017), and the antibacterial persistence after 10 washes was tested.

[0162] 3. Moisture management property test

[0163] (1) Water vapor transmission rate (WVTR) test: According to the ASTM E96 - 00 standard, the cup method was used to measure the water vapor transmission rate of the samples, and the test conditions were 23 °C / 50% RH.

[0164] (2) Vertical moisture absorption test: According to the standard of GB / T21655.1-2008, measure the vertical moisture absorption height of the sample within 30 minutes.

[0165] (3) Drying rate test: Immerse the sample until it is completely saturated, place it under the conditions of 35°C and 65% RH, weigh it every 5 minutes, and record the time required to recover to 95% of the initial weight.

[0166] 4. Structural characterization

[0167] Use a field emission scanning electron microscope (FE-SEM, Hitachi S-4800) to observe the microstructure of the sample, with an acceleration voltage of 5 kV. Use Fourier transform infrared spectroscopy (FTIR, Nicoleti S50) and X-ray photoelectron spectroscopy (XPS, Thermo ESCALAB250Xi) to analyze the chemical structure and surface composition of the sample.

[0168] 5. The test results are as follows:

[0169] Table 1 Mechanical property test results of each example and comparative example

[0170] Sample Tensile strength (MPa) Elongation at break (%) Young's modulus (MPa) Example 1 38.5 312 415 Example 2 35.8 345 385 Example 3 41.2 278 450 Example 4 39.6 305 430 Example 5 37.3 320 400 Example 6 40.5 290 440 Comparative Example 1 25.2 310 275 Comparative Example 2 39 315 410 Comparative Example 3 35.1 290 395 Pure PBAT 23.5 520 190

[0171] Table 2 Antibacterial property test results of each example and comparative example

[0172]

[0173] Table 3 Moisture management property test results of each example and comparative example

[0174] Sample <![CDATA[Water vapor transmission rate (g / m 2 ·24h)]]> Vertical moisture absorption height (cm) Drying time (min) Example 1 9500 15.5 18 Example 2 8750 14.2 21 Example 3 10200 16.3 15 Example 4 9850 15.8 17 Example 5 9300 14.8 19 Example 6 9750 16 16 Comparative Example 1 7200 12.3 28 Comparative Example 2 9450 15.3 18 Comparative Example 3 5600 10.5 35 Ordinary cotton fabric 3800 8.2 45

[0175] Through the analysis of the above test results, the following conclusions can be drawn:

[0176] 1. Mechanical properties: Examples 1-6 all showed excellent mechanical properties. The tensile strength was increased by 50-75% compared with pure PBAT, and at the same time, good flexibility was maintained (elongation at break > 270%). In Comparative Example 1, no nanocellulose functionalization treatment was carried out, and its tensile strength was significantly lower than that of the examples, indicating that the gradient functionalization of nanocellulose plays a key role in enhancing the interfacial bonding force and improving the mechanical properties of the composite material.

[0177] 2. Antibacterial performance: Examples 1-6 all showed excellent antibacterial effects. The 24-hour antibacterial rates against Staphylococcus aureus and Escherichia coli were both above 99%, and the antibacterial activity remained above 85% after 10 standard washes. In Comparative Example 2, no Chinese medicine microcapsules were added, and it had almost no antibacterial ability, proving that the compound extract of the three Huang herbs in Chinese medicine is the core source of the antibacterial function of the material. Although Comparative Examples 1 and 3 had certain antibacterial properties, the antibacterial retention rate after washing was significantly lower than that of the examples, indicating that the functionalization of nanocellulose and the hierarchical pore structure play an important role in antibacterial persistence.

[0178] 3. Moisture management performance: The water vapor transmission rates of Examples 1-6 were all above 8700 g / m 2 ·24h, the vertical moisture absorption height exceeded 14 cm, and the drying time was less than 21 minutes, showing excellent air permeability and quick-drying characteristics. In Comparative Example 3, the directional freezing technology was not used, and the water vapor transmission rate and moisture absorption height were significantly lower than those of the examples, and the drying time was almost doubled, proving that the hierarchical directional pore structure plays a decisive role in the air permeability and quick-drying performance of the material.

[0179] Example 3 showed the best comprehensive performance. Its tensile strength reached 41.2 MPa, the antibacterial persistence was the best (the retention rate after 10 washes was 92.1%), and the moisture management performance was also the most excellent (the water vapor transmission rate was 10200 g / m 2 ·24h, and the drying time was only 15 minutes). This may be related to its higher GMA grafting amount, lower concentration of the wall material of the Sanhuang microcapsules, and higher temperature gradient. These factors work together to form the best structural and functional synergistic effect.

[0180] The excellent performance of the Chinese medicine-nanocellulose composite tensile fiber fabric of the present invention stems from multiple synergistic action mechanisms:

[0181] 1. Synergistic enhancement mechanism of gradient-functionalized nanocellulose: The surface gradient functionalization of nanocellulose is achieved by controlling the grafting process of GMA and NIPAM. In the initial stage of the reaction, the initiator concentration is high, and GMA preferentially reacts with the hydroxyl groups on the surface of nanocellulose to form a highly functionalized outer layer region. As the reaction proceeds, the initiator concentration gradually decreases, and the degree of functionalization inside the fiber weakens accordingly, forming a gradient structure with a gradually decreasing degree of functionalization from the outside to the inside. This gradient structure retains the natural crystalline regions inside the fiber, maintains the mechanical strength of the material, and at the same time forms a highly active functional layer on the surface, providing conditions for the subsequent combination with the PBAT matrix.

[0182] The epoxy groups grafted with GMA can react with the terminal carboxyl and hydroxyl groups in PBAT to form covalent bond connections. FTIR analysis shows that the characteristic ester group peak at 1730 cm-1 and the weakening of the characteristic epoxy group peak at 910 - 920 cm-1 appear in the products of Examples 1 - 6, confirming the formation of chemical bonds between GMA and PBAT. At the same time, the grafted methacrylic acid chain segments are physically entangled with the PBAT molecular chains, increasing the interfacial entanglement points. As an interfacial compatibilizer, the carboxyl groups of oxidized starch form hydrogen bond networks with the hydroxyl groups of nanocellulose and the ester groups of PBAT, further enhancing the interfacial bonding. XPS analysis shows that in the interfacial region of Example 1, the content of C - O bonds increases by 25% compared with the raw materials, confirming the formation of a rich hydrogen bond and covalent bond network at the interface.

[0183] This multiple action mechanism significantly improves the interfacial tensile strength between the nanofibers and the matrix, makes the stress distribution more uniform, reduces stress concentration, and thus improves the overall tensile properties of the material. In Comparative Example 1, no functionalization treatment of nanocellulose was carried out, and its interfacial shear strength was only 1.8 MPa, while the interfacial shear strengths of Examples 1 - 6 were all above 3.5 MPa, nearly doubling.

[0184] 2. Multilevel structure moisture management synergistic mechanism: Through the directional freezing - lyophilization process, a hierarchical moisture transport channel network is formed. SEM observation shows that there is a three - level moisture transport channel structure in the products of Examples 1 - 6:

[0185] Nanoscale channels (2 - 5 nm): Capillary channels formed between nanocellulose molecules, providing a strong initial moisture absorption capacity

[0186] Micron - scale channels (5 - 20 μm): Oriented micropores formed by the growth of oriented ice crystals, providing a rapid moisture transport path

[0187] Macroscopic channels (50 - 200 μm): A network of ventilation pores formed in the whole material, promoting the evaporation and diffusion of moisture

[0188] This multilevel structure forms an efficient "unidirectional pump effect". The surface hydrophobic layer prevents external moisture from infiltrating, while the internal hydrophilic region absorbs sweat through capillary action. Due to the existence of the gradient structure, a concentration and surface energy gradient of moisture is formed in the material, generating a unidirectional and oriented transport effect, prompting moisture to always migrate from the skin side to the external environment, and still maintaining a dry feeling even in a high - humidity environment. Thermal infrared imaging observation shows that within 15 minutes after being wetted, the surface temperature of Example 3 drops by 3.5 °C, while that of Comparative Example 3 only drops by 1.2 °C, confirming that the multilevel pore structure significantly enhances the moisture evaporation and cooling effect.

[0189] In Comparative Example 3, the directional freezing technology was not adopted, and a randomly distributed porous structure was formed, lacking directionality, resulting in a significant reduction in the water transport efficiency. The dynamic water transport test showed that the one-way water transport index (OWTI) of Examples 1-6 was above 300, while that of Comparative Example 3 was only 120, indicating that the hierarchical pore structure formed by directional freezing is the key to achieving efficient one-way water transport.

[0190] 3. Synergistic antibacterial mechanism of the controlled release of traditional Chinese medicine extracts: The microcapsule system designed a dual response mechanism of pH and temperature. Chitosan swells in an acidic environment (pH < 6.5), and sodium alginate swells in an alkaline environment. This complementary property enables the microcapsules to increase permeability due to the swelling of the wall material when contacting sweat (pH 4.5 - 6.5). At the same time, the NIPAM grafted chains undergo a phase transition and shrink when the temperature is higher than 32 - 34 °C, further promoting the release of the contents. The fluorescence tracer experiment showed that the drug release rate of Example 1 reached 58% under the conditions of pH 5.5 and 35 °C for 24 hours, while it was only 12% under the conditions of pH 7.4 and 25 °C, confirming the effectiveness of the dual response mechanism.

[0191] The Sanhuang composite extract has a synergistic antibacterial effect through multiple mechanisms: Coptis chinensis (berberine) destroys the integrity of the bacterial cell membrane; Scutellaria baicalensis (baicalin) inhibits the activity of DNA gyrase; Phellodendron amurense (obacunone) inhibits cell wall synthesis. This multi-target synergistic effect not only improves the antibacterial efficiency but also reduces the risk of the development of bacterial drug resistance. The antibacterial mechanism study found that the Staphylococcus aureus cells treated with Example 1 shrank and ruptured, the ATP content decreased by 85%, and DNA synthesis was significantly inhibited.

[0192] The antibacterial experiment comparing single traditional Chinese medicine extracts showed that the minimum inhibitory concentration (MIC) of using only the Coptis chinensis extract was 128 μg / mL, while the MIC of the Sanhuang composite extract was only 50 μg / mL, a reduction of more than 60%, confirming the multi-component synergistic antibacterial effect. In Comparative Example 2, no traditional Chinese medicine components were added, and it had almost no antibacterial ability. In Comparative Example 1, although it contained traditional Chinese medicine components but was not functionally treated, its antibacterial persistence was significantly reduced, indicating that the functionalization of nanocellulose plays an important role in controlling the release of traditional Chinese medicine components.

[0193] In summary, the traditional Chinese medicine-nanocellulose composite tensile fiber fabric of the present invention realizes the synergistic enhancement of antibacterial, breathable and quick-drying, and mechanical properties through the organic combination of three innovative points: nanocellulose gradient functionalization, traditional Chinese medicine microcapsule controlled release technology, and hierarchical pore structure design, overcomes multiple technical bottlenecks of traditional antibacterial fabrics, and has significant technological innovation and application value. This material is expected to be widely used in the fields of sportswear, medical protective clothing, outdoor equipment, skin-friendly underwear, and functional home textile products.

Claims

1. Preparation method of traditional Chinese medicine-nanocellulose composite tensile fiber fabric, characterized in that It includes the following steps: (1) Nano-cellulose gradient functionalization treatment: In the presence of an initiator, graft glycidyl methacrylate (GMA) and N-isopropylacrylamide (NIPAM) onto the nano-cellulose aqueous dispersion in sequence to form nano-cellulose with gradient-functionalized surface; (2) Preparation of traditional Chinese medicine microcapsules: Extract Coptis chinensis, Scutellaria baicalensis, and Phellodendron amurense in a weight ratio of 1 - 3:0.5 - 1.5:0.5 - 1.5 to obtain a three-yellow composite extract, and use chitosan and sodium alginate as wall materials to prepare microcapsules by a pH / temperature dual-responsive cross-linking system; (3) Construction of composite materials: Mix the functionalized nano-cellulose, traditional Chinese medicine microcapsules, and oxidized starch, and blend them with a poly(butylene adipate-co-butylene terephthalate) (PBAT) solution to form a composite system; (4) Formation of hierarchical pore structure: Directionally freeze the composite system on a device with a temperature gradient, and then perform freeze-drying treatment to form a composite material with a hierarchical and oriented pore structure; (5) Hot pressing treatment: Perform hot pressing densification treatment under the conditions of 60 - 70 °C and 1.5 - 2.5 MPa; (6) Surface functionalization: Perform surface hydrophobization by silanization treatment, and then perform soft finishing and shaping treatment to obtain a traditional Chinese medicine-nano-cellulose composite tensile fiber fabric.

2. The preparation method according to claim 1, wherein The specific steps of the nano-cellulose gradient functionalization treatment in step (1) include: Under nitrogen protection, add the nano-cellulose aqueous dispersion (1.5 - 2.5 wt%) dropwise to GMA (15 - 25% of the weight of nano-cellulose) at 65 - 75 °C for 2.5 - 3.5 hours with ammonium persulfate (APS) as the initiator, then add NIPAM (10 - 20% of the weight of GMA) and react for 0.5 - 1.5 hours. After terminating the reaction, wash and redisperse to a solid content of 2 - 3 wt%.

3. The preparation method according to claim 1, characterized in that, The preparation method of the three-yellow composite extract in step (2) is: Coptis chinensis is extracted by refluxing with 55 - 65% ethanol (75 - 85 °C, 2.5 - 3.5 hours, solid-liquid ratio 1:8 - 12); Scutellaria baicalensis is extracted by ultrasonic-assisted extraction with 65 - 75% ethanol (55 - 65 °C, 1.5 - 2.5 hours, 250 - 350 W); Phellodendron amurense is extracted by microwave-assisted extraction with 45 - 55% ethanol (65 - 75 °C, 25 - 35 minutes, 450 - 550 W); Each extract is concentrated under reduced pressure, precipitated with ethanol, dried and powdered, and then mixed in proportion to obtain a composite extract.

4. The preparation method according to claim 1, characterized in that, The specific steps of microcapsule preparation in step (2) are: Disperse the three-yellow composite extract (2.5 - 3.5% w / v) in a chitosan solution (1.5 - 2.5% w / v), add NIPAM-grafted nano-chitosan (0.3 - 0.7% w / v), and dropwise add it to a sodium alginate solution (1.0 - 2.0% w / v) at a rate of 2 - 4 mL / min, stir (600 - 800 rpm, 25 - 35 minutes), add a glutaraldehyde solution (0.3 - 0.7% v / v) and cross-link for 5 - 15 minutes, adjust the pH to 7.0 - 7.5, and obtain microcapsules by centrifugal separation, washing, and freeze-drying.

5. The preparation method according to claim 1, characterized in that, The specific steps of composite material construction in step (3) are: Add oxidized starch (0.3 - 0.7% of the weight of cellulose) to the functionalized nanocellulose dispersion (1.5 - 2.5% w / v), stir at 30 - 40 °C for 30 - 50 minutes, add the microcapsule suspension (0.8 - 1.2% w / v), stir at room temperature for 1.5 - 2.5 hours, perform intermittent ultrasonic-assisted dispersion, stir at high speed and homogenize for 20 - 40 minutes, and refrigerate and let stand for 8 - 16 hours to form a stable composite system.

6. The preparation method according to claim 1, characterized in that, The specific steps for blending PBAT with the composite material in step (3) are as follows: PBAT is dissolved in chloroform to make a 6 - 8% w / v solution, add Span-80 (1.0 - 2.0% of the weight of PBAT) as an emulsifier, the volume ratio of the water phase to the organic phase is 2.5 - 3.5:1, slowly add the PBAT solution to the nanocellulose-microcapsule aqueous dispersion system, stir at high speed (700 - 900 rpm) to form a stable emulsion, perform intermittent ultrasonic treatment for 4 - 6 minutes, and evaporate part of the solvent under reduced pressure until the solid content is 4 - 6%.

7. The preparation method according to claim 1, wherein The specific steps for directional freezing in step (4) are as follows: Use a temperature gradient device with bottom refrigeration (-75 to -85 °C) and top insulation at room temperature, the temperature gradient is 12 - 22 °C / cm, pour the composite material suspension (1.0 - 1.5% w / v) into a mold to a thickness of 6 - 10 mm, place it on the temperature gradient device, control the cooling rate (1.5 - 2.5 °C / min) to form a directional ice crystal structure, and maintain the environment at -75 to -85 °C for 5 - 7 hours.

8. The preparation method according to claim 1, wherein, The specific parameters for freeze-drying treatment in step (4) are as follows: The initial temperature is -45 to -55 °C, the vacuum degree is 0.005 - 0.06 mbar, the heating program is to increase the temperature to 5 - 15 °C at a rate of 0.3 - 0.7 °C / h, the total freeze-drying time is 50 - 70 hours, and after freeze-drying is completed, it is cooled to room temperature before the vacuum is released.

9. The preparation method according to claim 1, characterized in that, The specific steps for surface functionalization in step (6) are as follows: The material is first vacuum-dried at 65 - 75 °C for 3 - 5 hours, then immersed in octadecyltrimethoxysilane (ODTMS) (1.5 - 2.5% v / v toluene solution), react at 80 - 90 °C for 4 - 6 hours under nitrogen protection, wash with toluene 2 - 4 times, wash with absolute ethanol 1 - 3 times, and vacuum-dry at 65 - 75 °C for 5 - 7 hours; then immerse in an aqueous solution of silicone softener (1.5 - 2.5% w / v) at 35 - 45 °C for 25 - 35 minutes, the squeezing ratio is 75 - 85%, dry in an oven (75 - 85 °C, 12 - 18 minutes), perform heat setting (105 - 115 °C, 1 - 3 minutes), and cool to room temperature.

10. The preparation method according to claim 1, characterized in that, The prepared traditional Chinese medicine-nanocellulose composite tensile fiber fabric is used to prepare sportswear, medical protective clothing, outdoor equipment, skin-friendly underwear or functional home textile products.

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