A multifunctional textile modified with core-shell nanoparticles and its preparation method

Abstract

This invention discloses a multifunctional textile modified with core-shell nanoparticles and its preparation method. The method involves reacting a core-shell polymethyl methacrylate (PMMA)@TiO2 nanoparticle ionic liquid solution with the fabric. Through ionic liquid catalysis, the aldehyde and carboxyl groups in the green crosslinking agent, nano-oxidized chitosan microparticles, form Schiff bases, amide bonds, and acetal bonds with the amino and hydroxyl groups in the fabric, resulting in multi-site grafting of the core-shell nanoparticles onto the fabric surface. The core-shell nanoparticles are uniformly distributed in the fabric, exhibiting strong stability, high efficiency and long-lasting functionality, and good wash resistance. The preparation process of this invention is simple, low-cost, and uses mild and controllable reaction conditions without the use of any toxic additives, making it environmentally friendly. The prepared PMMA@TiO2 nanoparticle-grafted fabric is soft, moisture-wicking, breathable, and skin-friendly, providing comfortable wear. It also offers long-lasting antibacterial, wrinkle-resistant, UV-protective, and self-cleaning functions, demonstrating broad market prospects.

Description

Technical Field

[0001] This invention relates to a multifunctional textile modified with core-shell nanoparticles and its preparation method, and particularly to a technology for in-situ grafting of core-shell nanoparticles with textiles using a green crosslinking agent, nano-oxidized chitosan, which belongs to the field of functional textile material preparation technology. Background Technology

[0002] With the improvement of people's living standards and the acceleration of work pace, functional textiles are gradually penetrating into all aspects of daily life. Functional textiles based on nanomaterials have become a hot research topic, and are widely used in fields such as flame retardancy, antibacterial properties, superhydrophobicity, self-cleaning, UV resistance, and antistatic properties [Zhu Y, Long J. Development of a novel, sustainable and protective multi-flow dyeing methodology for silk substrate. Journal of Cleaner Production, 2023, 399:136632]. Nanomaterials exhibit a unique small-size effect, with significantly enhanced chemical activity, biological activity, adsorption capacity, and specific surface area, making them widely used as functional finishing agents for textiles. Small nanoparticles not only adhere to the fiber surface but can also enter the pores within the fiber to perform functional filling, while having minimal impact on the textile's hand feel, breathability, and other wearing properties, demonstrating unique application advantages.

[0003] Textiles are favored for their skin-friendliness, moisture absorption, breathability, and comfort, but most textiles have poor antibacterial properties, are prone to deformation after washing, are difficult to care for, and easily attract stains. With the accelerating pace of modern life, functional textiles are gaining increasing attention. As the global ecological environment continues to deteriorate and non-renewable resources such as oil and coal become increasingly scarce, the effective utilization of biomass renewable resources is receiving more and more extensive research. "Ecological priority and green, low-carbon" have become basic requirements for the development of various industries worldwide. The research and industrial application of textiles that are "healthy, comfortable, clean, convenient, and multifunctional" have broad market prospects and enormous development potential.

[0004] Titanium dioxide and chitosan are often used for functional modification of textiles due to their eco-friendliness, excellent performance, and low cost. However, both are subject to several limitations in practical applications: nano-TiO2 particles are prone to aggregation, affecting dispersion uniformity; TiO2 has a high probability of electron-hole recombination, resulting in low photocatalytic activity; and nano-TiO2 is difficult to firmly graft onto fiber surfaces. Large-molecule chitosan is almost insoluble in neutral water, requiring acidic solutions, molecular weight reduction, or other special methods to improve its water solubility. However, acidic solutions are highly corrosive, volatile, and pollute the environment. Furthermore, the chitosan backbone units contain only hydroxyl and amino groups, typically requiring chemical cross-linking agents such as glutaraldehyde and polycarboxylic acids for firm grafting onto fibers, thus affecting the biocompatibility advantages of chitosan and negatively impacting the excellent properties of fibers and human health.

[0005] In recent years, core-shell TiO2 composite materials have been widely used. Numerous studies have shown that the special bilayer structure, while retaining the original properties of both materials, promotes synergistic effects between them. By selecting appropriate materials, it is possible to help suppress the rapid recombination of TiO2 electron-hole pairs, improve the uniformity of TiO2 particle dispersion, increase the utilization rate of TiO2 visible light, or enhance the absorption capacity of TiO2 ultraviolet light. Furthermore, "organic-inorganic" core-shell materials can also increase reactive functional groups and improve the durability of TiO2 core-shell nanomaterials combined with fibers. Currently, the mature and low-cost organic "core" materials are mainly composite polymers based on polystyrene (PS). However, the preparation process uses a lot of initiators, surfactants and other reagents, and polystyrene has carcinogenic risks, which limits its application. In addition, polystyrene@TiO2 core-shell nanomaterials also need to be cross-linked with fabrics by chemical cross-linking agents, and the outer TiO2 particles are in direct contact with the fiber. During photocatalysis, the reactive oxygen species generated can photo-erode the fiber matrix, causing mechanical damage to textiles [Li Y, Shen Q, Guan R, et al. AC@TiO2yolk-shell hetero-structure for synchronous photothermal-photocatalytic degradation of organic pollutants. Journal of Materials Chemistry C, 2020, 8: 1025-1034]. Invention patent CN102677465B discloses a functionalized nano-chitosan and nano-TiO2 modified tussah silk fabric and its preparation method. The method involves dissolving chitosan in acetic acid solution, adding sodium tripolyphosphate (TPP) solution and nano-TiO2 sol dropwise, and stirring vigorously to obtain a chitosan / TiO2 composite nano-finishing solution with a particle size of less than 100 nm. This solution is then used to treat the tussah silk fabric to obtain antibacterial and UV-protective functional textiles. However, this method involves a complex preparation process, using butanetetracarboxylic acid, polymaleic acid, and tartaric acid as crosslinking agents and hypophosphite as a catalyst. Furthermore, the tussah silk fabric is baked at a high temperature of 165–170 °C, causing the crosslinking agents to undergo an esterification reaction with the silk, resulting in mechanical damage and reduced wearing performance of the tussah silk fabric.

[0006] This invention utilizes plant-based oil monomers methyl methacrylate (MMA) and hydroxyethyl acrylate (HEA) as raw materials to prepare polymethyl methacrylate (PMMA) microspheres as the "core" via a soap-free emulsion polymerization hydrothermal reaction. TiO2 is then added dropwise under ultrasonic conditions. + / TPP -Composite particle solutions are electrostatically assembled onto the periphery of PMMA microspheres to form a "shell," thereby preparing core-shell polymethyl methacrylate (PMMA)@TiO2 nanoparticles with uniform particle size. Then, under microwave irradiation in an ionic liquid, these core-shell nanoparticles are grafted onto the surface of a pretreated fabric via a green crosslinking agent, nano-oxidized chitosan, to obtain multifunctional textiles modified with core-shell nanoparticles. PMMA exhibits good transparency, increasing visible light utilization, and electrostatically attracts nano-TiO2, preventing the aggregation of nano-TiO2 particles. Simultaneously, the ester, carboxyl, aldehyde, and amino groups in the PMMA microspheres and nano-oxidized chitosan can attract photogenerated holes and electrons from TiO2, effectively preventing rapid recombination and enhancing photocatalytic activity. Monomers such as PMMA and hydroxyethyl acrylate are derived from natural plant oils, making them renewable, low-cost, safe, environmentally friendly, with fast polymerization rates and low auxiliary agent usage. Furthermore, the green crosslinking agent, nano-oxidized chitosan, is an amphoteric polyelectrolyte with a structure similar to proteins. It possesses superior water solubility, biocompatibility, degradability, long-lasting antibacterial properties, reactivity, and safety (non-toxicity). The numerous polar groups such as carboxyl, aldehyde, and amino groups in nano-oxidized chitosan readily react with fibers, thereby endowing textile materials with multiple functions such as antibacterial and antiviral properties, UV protection, wrinkle resistance, self-cleaning, biocompatibility, and comfortable wear, while avoiding the photocorrosion side effects of nano-TiO2 on the fiber matrix. The method of this invention is simple, low-cost, and uses mild reaction conditions, making it environmentally friendly. The resulting core-shell nanoparticle-modified multifunctional textiles have broad application prospects in textiles, apparel, home textiles, packaging, biomedicine, and environmental fields. Summary of the Invention

[0007] The purpose of this invention is to provide a method for preparing multifunctional textiles modified with core-shell nanoparticles, thereby enhancing the textile's antibacterial, UV-protective, wrinkle-resistant, moisture-wicking, breathable, skin-friendly, and self-cleaning properties. Polymethyl methacrylate (PMMA) microspheres are prepared as the "core" through a hydrothermal reaction-based soap-free emulsion polymerization of monomers methyl methacrylate (MMA) and hydroxyethyl acrylate (HEA). TiO2 is then added dropwise under ultrasonic conditions. + / TPP - Core-shell polymethyl methacrylate (PMMA) nanoparticles with uniform particle size are prepared by electrostatically assembling a composite particle solution around PMMA microspheres as a "shell". Then, under microwave irradiation in an ionic liquid, the core-shell nanoparticles are grafted onto the surface of a pretreated fabric using a green crosslinking agent, nano-chitosan oxide. This method is simple, low-cost, uses mild and controllable reaction conditions, does not use any toxic additives, is environmentally friendly, and has a wide range of applications.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0009] A multifunctional textile modified with core-shell nanoparticles is characterized in that: the multifunctional textile modified with core-shell nanoparticles is obtained by reacting an ionic liquid solution of core-shell polymethyl methacrylate@TiO2 nanoparticles with the fabric, and by using ionic liquid catalysis to catalyze the formation of Schiff bases, amide bonds, and acetal bonds between the aldehyde and carboxyl groups in the green crosslinking agent nano-oxidized chitosan particles and the amino and hydroxyl groups in the fabric, thereby grafting the core-shell polymethyl methacrylate@TiO2 nanoparticles onto the fabric surface at multiple sites.

[0010] The core-shell polymethyl methacrylate@TiO2 nanoparticles of this invention are obtained by the following method:

[0011] (1) Methyl methacrylate monomer and hydroxyethyl acrylate monomer are dissolved in deionized water to prepare a solution with a total mass concentration of 10-35%. Nitrogen gas is introduced for 15-30 min, and azobisisobutyramidine hydrochloride initiator is added to make its mass concentration in the solution 0.2-1.2%. Soap-free emulsion polymerization reaction is carried out at 60-85℃ with stirring at 250-800 r / min for 2-5 h. After the reaction, the solution is sieved through a 200-mesh standard sieve 3-5 times to obtain a uniform and stable milky white polymethyl methacrylate microsphere dispersion. The mass ratio of methyl methacrylate to hydroxyethyl acrylate is 1-12:1.

[0012] (2) Add deionized water to the dispersion from step (1) to make the mass concentration of polymethyl methacrylate microspheres 0.08–0.25%. Adjust the pH of the solution to 2.6–3.8 with 0.03 mol / L dilute hydrochloric acid solution to prepare anatase-phase nano-TiO2 sol with a mass concentration of 0.1–0.2%. Add negatively charged sodium tripolyphosphate (TPP) - Stir and mix evenly to form TiO2 + / TPP - Composite particles; then TiO2 is slowly and uniformly added dropwise at a rate of 1.2–2.6 mL / min using a constant pressure funnel. + / TPP - The composite particle solution was added to the polymethyl methacrylate (PMMA) microsphere dispersion, and simultaneously a probe-type ultrasonic instrument was turned on to treat the microspheres at 100–280 W and 25–40 °C for 30–60 min. This allowed the negatively charged groups such as ester and hydroxyl groups on the surface of the PMMA microspheres, as well as the cationic free radicals from the decomposition of the initiator azobisisobutyramidine hydrochloride, to react with TiO2. + / TPP -The composite particles generate electrostatic forces, which then electrostatically assemble them into a core-shell polymethyl methacrylate@TiO2 nanoparticle dispersion. The dispersion is then dried in a spray dryer for 25–45 min to obtain polymethyl methacrylate@TiO2 nanoparticle powder with uniform particle size and stable core-shell structure. The mass ratio of polymethyl methacrylate to anatase nano-TiO2 is 2–8:1, and the mass ratio of sodium tripolyphosphate to anatase nano-TiO2 is 1–6:1.

[0013] Preferably, the nano-TiO2 is anatase type with an average particle size of 32–50 nm and a Zeta potential of 28.66–40.19 mV; the core-shell polymethyl methacrylate@TiO2 nanoparticles have a particle size range of 315–520 nm, a Zeta potential of 30.24–47.93 mV, and a monodispersity index of 0.116–0.307.

[0014] Preferably, the spray dryer has an inlet air temperature of 75–100°C, a moisture evaporation rate of 10–32 kg / h, an outlet air temperature of 30–45°C, and a power of 30–76 kW.

[0015] Preferably, the fabric is a natural fiber or chemical fiber fabric or a blend of both.

[0016] The method for preparing multifunctional textiles modified with core-shell nanoparticles according to the present invention is as follows: core-shell polymethyl methacrylate@TiO2 nanoparticles are ultrasonically dispersed in an ionic liquid to prepare a finishing solution with a mass concentration of 0.2-0.8%; then, a green crosslinking agent, nano-oxidized chitosan, is added to make its mass concentration in the finishing solution 0.2-0.6%; and the pH of the finishing solution is adjusted to 4.0-5.2 by adding 0.1 mol / L HCl solution dropwise.

[0017] The fabric is immersed in a NaHCO3 solution with a mass concentration of 10-15 g / L at 80-90°C for 30-60 min, then ultrasonically cleaned with anhydrous ethanol until neutral, dried, and then placed in a high-density microwave plasma treatment instrument with air introduced. Glow discharge is performed at a vacuum degree of 30-62 Pa for 3-8 min, and air is introduced for another 12-18 min to obtain the pretreated fabric.

[0018] The pretreated fabric was placed in the finishing solution at a bath ratio of 1g:50mL and stirred at 30-45℃ for 1-3h under microwave radiation of 180-350W. The fabric was then removed and soaked in a mixture of anhydrous ethanol and deionized water at a volume ratio of 1:1 to remove the ionic liquid. The fabric was then placed in a supercritical carbon dioxide dryer for 45-90min and vacuum dried at 40℃ for 1-2h. After washing with deionized water 3-5 times and air-drying, a multifunctional textile modified with core-shell nanoparticles was obtained.

[0019] Preferably, the nano-oxidized chitosan has a degree of deacetylation ≥91.62%, an aldehyde content of 21.18–30.49% at C2 and C3 positions, a carboxyl content of 52.36–75.51% at C6 position, an isoelectric point pH of 5.8–6.1, an average particle size of 185–316 nm, and a Zeta potential of 27.13–38.54 mV; the structural formula of the nano-oxidized chitosan is as follows:

[0020]

[0021] Preferably, the ionic liquid is selected from 1-ethyl acetate-3-methylimidazolium tetrafluoroborate, 1-(3-sulfopropyl)caprolactam hydrogen sulfate, 1-(3-sulfopropyl)caprolactam hydrogen phosphate, 3-N,N,N-trimethylammonium propanesulfonic acid hydrogen sulfate, 1-hydroxyethyl-3-methylimidazolium hydrochloride, 1-hydroxyethyl-3-butylimidazolium hydrochloride, or 1-carboxymethyl-3-methylimidazolium hydrochloride.

[0022] Preferably, the high-density microwave plasma processor has a microwave power of 850–1260 W and a microwave frequency of 2.45 GHz.

[0023] Preferably, the supercritical carbon dioxide dryer has a power of 1.5 to 4.6 kW, a working pressure of 800 to 2500 psi, a drying temperature of -30 to 40°C, and a medium flow rate of 500 to 1200 mL / min.

[0024] By optimizing the mass concentration of core-shell polymethyl methacrylate@TiO2 nanoparticles and the green crosslinking agent nano-oxidized chitosan, the time and power of high-density microwave plasma treatment of the fabric, and the microwave radiation reaction time, temperature and power, a series of modified fabrics with different grafting rates of core-shell polymethyl methacrylate@TiO2 nanoparticles can be obtained.

[0025] Compared with existing technologies, the preparation principle and advantages of the multifunctional textiles modified with core-shell nanoparticles in this invention are as follows:

[0026] 1. This invention utilizes plant oil-based monomers methyl methacrylate and hydroxyethyl acrylate as raw materials, which are abundant, renewable, safe, and non-toxic. Polymethyl methacrylate (PMMA) microspheres are prepared as the "core" through hydrothermal soap-free emulsion polymerization. The biggest advantage of soap-free emulsion polymerization is that no emulsifier is used during the polymerization process. The resulting polymer emulsion has good water resistance, is pure, free of impurities, and has a low monomer concentration. The soap-free emulsion polymerization system mainly includes monomers, water, initiators, and possibly a small amount of ionic comonomers. Due to the purity of the product, it has important applications in drug sustained release, biomedicine, and other fields. In soap-free emulsion polymerization, methyl methacrylate monomers are slightly soluble in water, with a small portion existing in the continuous aqueous phase. Upon heating with a cationic initiator, these monomers decompose to form cationic primary free radicals, initiating the polymerization of methyl methacrylate monomers in the continuous aqueous phase to form oligomeric free radicals. Once these oligomeric free radicals reach a certain length, they precipitate from the water, forming "oligomeric free radical chains." Multiple "oligomeric free radical chains" attract and entangle with each other to form primary particles. These primary particles aggregate and simultaneously absorb methyl methacrylate monomers from the water, ultimately forming stable colloidal particles through the polymerization reaction. Because the number of particles formed during soap-free emulsion polymerization is relatively small, it easily results in polymer particles with a larger size (above 200 nm). Furthermore, polymethyl methacrylate (PMMA) prepared by soap-free emulsion polymerization is a type of acrylic glass, possessing advantages such as high transparency, good thermal stability, and low cost. When PMMA is coated with nano-TiO2, it forms core-shell polymethyl methacrylate@TiO2 nanoparticles, exhibiting strong stability, uniform particle size, and high photocatalytic activity.

[0027] 2. In this invention, anatase-phase nano-TiO2 sol is dispersed in a dilute hydrochloric acid solution with a pH of 2.6–3.8 to form positively charged nano-TiO2 particles. The positively charged nano-TiO2 particles attract the phosphate anions (P3O4) of sodium tripolyphosphate (TPP) through electrostatic attraction. 10 5- Combined to form stable TiO2 + / TPP - Composite particles are electrostatically bonded to the negatively charged groups such as ester and hydroxyl groups on the surface of polymethyl methacrylate (PMMA) microspheres and to the cationic free radicals generated from the decomposition of azobisisobutyramidine hydrochloride initiator, thereby electrostatically assembling into core-shell PMMA@TiO2 nanoparticles. Simultaneously, the negatively charged groups such as ester and hydroxyl groups on the PMMA microspheres and the cationic groups generated from the decomposition of azobisisobutyramidine hydrochloride initiator can attract photogenerated holes (positively charged) and electrons (negatively charged) from nano-TiO2, effectively inhibiting their rapid recombination and improving photocatalytic activity. Furthermore, the PMMA microspheres produced by soap-free emulsion polymerization have a large particle size, allowing for the electrostatic assembly of more TiO2 particles on their surface. They possess advantages such as uniform particle size distribution, stable core-shell structure, high bioactivity, no need for crosslinking agents, and strong photocatalytic ability.

[0028] 3. This invention uses TiO2 + / TPP - A composite particle solution was dropwise added to a polymethyl methacrylate (PMMA) microsphere dispersion. An ultrasonic probe was used to induce an ultrasonic reaction, followed by electrostatic assembly into core-shell nanospheres. In this ultrasonic chemical reaction, the multiple effects of ultrasound—dispersion, pulverization, and activation—promote both homogeneous reactions and nanoparticle dispersion. Simultaneously, ultrasound generates cavitation, leading to the formation, growth, and collapse of cavitation bubbles in the reaction solution. The collapse of these cavitation bubbles generates temperatures exceeding 5000 K and pressures exceeding 200 MPa within a very short time and a small space, providing an energy source for the ultrasonic chemical synthesis and significantly accelerating the reaction. Ultrasound also influences the reaction of PMMA microspheres, cationic initiators, and TiO2. + / TPP - The electrostatic bonding of the composite particles plays an activating role. The intense impact and cavitation of ultrasound dissociate water molecules adsorbed on the surface of nano-TiO2, forming hydroxyl groups. This increases the active groups on the surface of the TiO2 particles, promoting the ultrasonic chemical cross-linking of the nano-TiO2 particles with polymethyl methacrylate microspheres and a cationic initiator. This results in uniformly sized and highly stable polymethyl methacrylate@TiO2 core-shell nanoparticles. Simultaneously, the pH of the reaction solution (2.6–3.8) is lower than the isoelectric point of the TiO2 particles (pH ≥ 4.0), giving the TiO2 nanoparticles a positive charge. This significantly increases the electrostatic attraction and reaction efficiency of the positively charged TiO2 nanoparticles to the ester and hydroxyl groups on the surface of the negatively charged polymethyl methacrylate microspheres, thereby greatly increasing the dispersibility of the nano-TiO2 particles and their coating rate and stability on the polymethyl methacrylate microsphere surface.

[0029] 4. In this invention, hydroxyethyl acrylate monomer is added during the soap-free emulsion polymerization process. Hydroxyethyl acrylate has good compatibility with methyl methacrylate, and the monomer droplets formed in the emulsion are small in size, which helps to polymerize into polymethyl methacrylate microspheres with uniform particle size. In addition, the hydroxyethyl acrylate monomer contains more polar carboxyl groups, and the polymethyl methacrylate microspheres have a higher content of negatively charged carboxyl groups on their surface, which enhances the electrostatic attraction to positively charged TiO2 nanoparticles and is conducive to the formation of stable core-shell polymethyl methacrylate@TiO2 nanoparticles.

[0030] 5. This invention uses nano-oxidized chitosan as a green crosslinking agent for polymethyl methacrylate@TiO2 core-shell microparticles and fabrics. Oxidized chitosan selectively oxidizes the secondary hydroxyl groups at C2 and C3 positions of the chitosan molecule to aldehyde groups and the primary hydroxyl group at C6 position to carboxyl groups, thus maintaining the alkaline polysaccharide characteristics of chitosan. It has advantages such as good water solubility, biocompatibility, degradability, reactivity, antibacterial properties, environmental friendliness, and safety and non-toxicity. Nano-sized chitosan oxidized molecules contain negatively charged groups such as carboxyl, aldehyde, and hydroxyl groups, which enhance the electrostatic attraction with positively charged TiO2 nanoparticles and prevent the rapid recombination of photogenerated electron-hole pairs in TiO2. Simultaneously, the carboxyl group at the C6 position of nano-chitosan oxidized molecules can rotate freely in spatial conformation, exhibiting low steric hindrance and high chemical activity. It readily undergoes amide reactions with the amino groups of protein fibers, and the aldehyde groups of nano-chitosan oxidized molecules can also undergo Schiff base and acetal crosslinking with the amino and hydroxyl groups of fibers. This significantly improves the binding strength and grafting rate of core-shell polymethyl methacrylate@TiO2 nanoparticles on fabrics, resulting in more pronounced antibacterial, UV-protective, and self-cleaning functions of modified fabrics. Furthermore, the small size and uniform distribution of nano-chitosan oxidized particles on the fiber surface prevent the crosslinking and film formation of large-molecule chitosan, which can lead to a decrease in fabric feel and breathability. Nano-chitosan oxidized molecules can also penetrate into the internal pores of fibers, achieving functional filling. The large specific surface area provides modified fabrics with more active centers, resulting in superior performance and wider applications.

[0031] 6. This invention introduces hydrophilic groups such as aldehyde and carboxyl groups into nano-chitosan molecules, improving the biocompatibility and stability of the nanoparticles in aqueous solutions. By crosslinking core-shell polymethyl methacrylate (PMMA)@TiO2 nanoparticles with nano-chitosan, it achieves long-lasting antibacterial, wrinkle-resistant, UV-protective, and self-cleaning functions on the fabric surface. Simultaneously, nano-chitosan is environmentally friendly, has a broad-spectrum bactericidal effect, is stable, non-toxic, safe to use, and has a large specific surface area. Its synergistic effect with the photodynamic bactericidal PMMA@TiO2 core-shell nanoparticles further endows the modified fabric with dual antibacterial capabilities. Meanwhile, the pH of the finishing solution (4.0–5.2) is lower than the isoelectric point (pH 5.8–6.1) of nano-oxidized chitosan, causing the nano-oxidized chitosan particles to exhibit positive charge. This enhances the electrostatic attraction and grafting reaction efficiency with negatively charged cotton and silk fabrics (isoelectric point pH around 3.2). Furthermore, the aldehyde and carboxyl anions and amino cations in the nano-oxidized chitosan react with the TiO2 on the exterior of the polymethyl methacrylate@TiO2 core-shell particles. + / TPP -The composite particles form a strong electrostatic force, improving the bonding strength and grafting rate of polymethyl methacrylate (PMMA)@TiO2 core-shell nanoparticles on the fabric. Simultaneously, the green crosslinking agent, nano-oxidized chitosan, is grafted onto the fabric surface, and then electrostatically bonded to the PMMA@TiO2 core-shell nanoparticles. This effectively prevents the TiO2 particles from photo-eroding the fabric matrix, does not affect the fabric's mechanical properties, and the nano-oxidized chitosan is highly bioactive, biodegradable, safe, hygienic, and has good applicability.

[0032] 7. This invention involves immersing fabric in a core-shell polymethyl methacrylate@TiO2 nanoparticle ionic liquid under microwave irradiation. Due to the rapid heating speed of microwave irradiation, the reaction time is short and the uniformity is good. The core-shell nanoparticles can fully contact the active sites of the fabric, significantly accelerating the reaction rate. This effectively avoids the aggregation and uneven dispersion of nanoparticles caused by long-term treatment, and ensures that the core-shell nanoparticles are uniformly grafted onto the fabric surface. This solves the shortcomings of traditional water bath heating reaction process, such as long reaction time, low grafting reaction rate, easy agglomeration of nanoparticles in the finishing solution, and uneven distribution on the fabric surface. Meanwhile, core-shell nanoparticles are grafted onto the fabric surface using a green crosslinking agent, nano-oxidized chitosan, in an ionic liquid. The ionic liquid can absorb the water generated during the reaction of nano-oxidized chitosan with fabric amides, acetals, etc., promoting the forward progress of the grafting reaction, accelerating the reaction rate, improving grafting efficiency, and enhancing the functionality of the modified fabric. At the same time, the acidic ionic liquid can make the amino groups of nano-oxidized chitosan positively charged, catalyzing the nucleophilic addition reaction between nano-oxidized chitosan and the fabric, thereby improving the grafting efficiency of core-shell nanoparticles on the fabric surface.

[0033] 8. This invention utilizes supercritical carbon dioxide drying technology to dry fabrics grafted with core-shell polymethyl methacrylate (PMMA)@TiO2 nanoparticles. The drying medium, in a supercritical state, enters the interior of the fabric and undergoes a gentle and rapid exchange with solvent molecules, displacing the solvent. The fluid then transitions from a supercritical state to a gas and is released, achieving the drying effect. The modified fabric is dried under the critical temperature and pressure conditions of the drying medium. When the drying medium is in a supercritical state, the substance exists as a supercritical fluid with both gas and liquid properties. At this point, the gas-liquid interface of the drying medium disappears, and the surface tension of the supercritical fluid approaches zero. Therefore, it effectively prevents the volume shrinkage and fragmentation of the nanoparticles during drying, maintaining the original core-shell structure and state of the nanoparticles and preventing the aggregation of core-shell nanoparticles on the fabric surface. The supercritical fluid drying process is gentle, has a high diffusion coefficient, and dries faster. Under high pressure, it also has a bactericidal effect during solvent removal, resulting in high purity and safety. Supercritical fluid drying exhibits good thermal stability, allows for large-scale drying of samples with minimal sample damage, and can be applied on a large scale.

[0034] 9. This invention employs high-density microwave plasma for pretreatment of fabrics. Microwave plasma uses electromagnetic wave energy to excite the reactive gas, resulting in electrodeless discharge and no electrode pollution. Simultaneously, the microwave discharge region is concentrated rather than diffused, generating high-density and highly active ions that activate various atomic groups on the fiber surface, ensuring uniform sample treatment. Furthermore, the low self-bias voltage of microwave plasma minimizes damage to the material's structure and physical properties. Microwave plasma treatment is low-cost, simple, reliable, and fast. The high-density free radicals formed on the fiber surface by microwave plasma treatment undergo oxidation reactions under air conditions, introducing oxygen-containing polar groups such as carboxyl and carbonyl groups onto the fiber surface. These active groups are then used to graft onto nano-oxidized chitosan and core-shell nanoparticles, achieving durable and effective functionality. Simultaneously, microwave plasma treatment etches the fiber surface, making it rougher and effectively enhancing the grafting and adhesion strength of core-shell nanoparticles. This effectively avoids the use of adhesives and toxic crosslinking agents, reducing waste liquid generation and making it environmentally friendly.

[0035] 10. This invention uses a spray dryer to dry a core-shell polymethyl methacrylate (PMMA)@TiO2 nanoparticle dispersion. The solution is sprayed into a mist by a high-speed centrifugal atomizer, allowing it to come into contact with hot air and be dried into a finished product in a very short time. The drying speed is fast, and the surface area of ​​the solution is greatly increased after atomization. In the hot air flow, 95-98% of the water can be evaporated instantly, and the drying time is only a few seconds. The product has good particle distribution uniformity, flowability and solubility, high purity and good quality. Moreover, the production process is simplified and the operation and control are convenient. It can obtain PMMA@TiO2 nanoparticle powder with uniform particle size and stable core-shell structure. Attached Figure Description

[0036] Figure 1 This is a schematic diagram illustrating the principle of preparing core-shell polymethyl methacrylate@TiO2 nanoparticles according to the present invention.

[0037] Figure 2 This is a transmission electron microscope (TEM) image of the core-shell polymethyl methacrylate@TiO2 nanoparticles prepared in Comparative Example 2 of this invention.

[0038] Figure 3 This is a transmission electron microscope (TEM) image of the core-shell polymethyl methacrylate@TiO2 nanoparticles prepared in Example 3 of this invention.

[0039] Figure 4 This is a transmission electron microscope image of the nano-oxidized chitosan prepared in Example 3 of the present invention. Detailed Implementation

[0040] The present invention will be further described below with reference to the accompanying drawings and embodiments. The following reference embodiments are for illustrative purposes only and do not limit the present invention in any way.

[0041] I. Preparation of Multifunctional Textiles Modified with Core-Shell Nanoparticles

[0042] Example 1

[0043] (1) Methyl methacrylate monomer and hydroxyethyl acrylate monomer were dissolved in deionized water to prepare a solution with a total mass concentration of 12%, wherein the mass ratio of methyl methacrylate to hydroxyethyl acrylate was 12:1. Nitrogen gas was introduced for 18 min, and azobisisobutyramidine hydrochloride was added to make its mass concentration in the solution 0.2%. Soap-free emulsion polymerization was carried out at 60°C and stirred at 300 r / min for 2 h. After the reaction was completed, the solution was sieved 4 times through a 200 mesh standard sieve to obtain a uniform and stable milky white polymethyl methacrylate microsphere dispersion.

[0044] (2) Add deionized water to the dispersion from step (1) to make the mass concentration of polymethyl methacrylate microspheres 0.08%, and adjust the pH of the solution to 2.8 with 0.03 mol / L dilute hydrochloric acid solution; prepare an anatase phase nano-TiO2 sol (average particle size 42 nm, Zeta potential 30.57 mV) with a mass concentration of 0.1%, and add negatively charged sodium tripolyphosphate (TPP) - Stir and mix evenly to form TiO2 + / TPP - Composite particles were prepared to achieve a 1:1 mass ratio of sodium tripolyphosphate to anatase nano-TiO2; then, TiO2 was slowly and uniformly added dropwise at a rate of 1.5 mL / min using a constant pressure funnel. + / TPP - The composite particle solution was added to a polymethyl methacrylate (PMMA) microsphere dispersion, maintaining a PMMA to anatase-phase nano-TiO2 mass ratio of 8:1. Simultaneously, a probe-type ultrasonic instrument was used to treat the microspheres at 140W and 25℃ for 35 minutes. This allowed the negatively charged groups (ester groups, hydroxyl groups, etc.) on the surface of the PMMA microspheres, as well as the cationic free radicals from the decomposition of the initiator azobisisobutyramidine hydrochloride, to react with the TiO2. + / TPP - The composite particles generate electrostatic forces, which then electrostatically assemble them into a core-shell polymethyl methacrylate@TiO2 nanoparticle dispersion. The dispersion is then placed in a spray dryer (inlet air temperature of 78℃, water evaporation rate of 15kg / h, outlet air temperature of 35℃, and power of 36kW) for 30 minutes to obtain a core-shell polymethyl methacrylate@TiO2 nanoparticle powder with a uniform particle size range of 332nm, a Zeta potential of 31.70mV, and a monodispersity index of 0.289, and a stable core-shell structure.

[0045] (3) The core-shell polymethyl methacrylate@TiO2 nanoparticles obtained in step (2) were ultrasonically dispersed in 1-(3-sulfopropyl)caprolactam hydrogen sulfate ionic liquid to prepare a finishing solution with a mass concentration of 0.2%. Then, green crosslinking agent nano-oxidized chitosan (degree of deacetylation of 92.06%, aldehyde content of C2 and C3 positions of 24.63%, carboxyl content of C6 position of 54.18%, isoelectric point pH=6.0, average particle size of 196nm, and Zeta potential of 29.21mV) was added to make its mass concentration in the finishing solution 0.3%. The pH of the finishing solution was adjusted to 4.2 by adding 0.1mol / L HCl solution dropwise.

[0046] The viscose fabric was immersed in a 10 g / L NaHCO3 solution at 82°C for 35 min, then ultrasonically cleaned with anhydrous ethanol until neutral, dried, and then placed in a high-density microwave plasma treatment instrument with a microwave power of 920 W and a microwave frequency of 2.45 GHz. Air was introduced and glow discharge was performed at a vacuum degree of 42 Pa for 4 min. Air was then introduced for another 12 min to obtain the pretreated viscose fabric.

[0047] The pretreated viscose fabric was placed in the finishing solution at a bath ratio of 1g:50mL and stirred at 30℃ for 1.5h under microwave radiation with a power of 200W. The viscose fabric was then removed and soaked in a mixture of anhydrous ethanol and deionized water with a volume ratio of 1:1 to remove the 1-(3-sulfopropyl)caprolactam hydrogen sulfate ionic liquid. The viscose fabric was then placed in a supercritical carbon dioxide dryer with a power of 1.8kW, a working pressure of 980psi, a drying temperature of -10℃, and a medium flow rate of 600mL / min for 50min. It was then vacuum dried at 40℃ for 1h, washed 4 times with deionized water, and air-dried to obtain a multifunctional textile modified with core-shell nanoparticles.

[0048] Antibacterial tests were conducted on core-shell polymethyl methacrylate (PMMA)@TiO2 nanoparticle-modified viscose fabric according to AATCC Test Method 100-1999, "Quantitative Test Methods." The inhibition rate against Staphylococcus aureus was 99.17%, and against Escherichia coli was 99.03%. After 50 washes, it met the AAA-grade antibacterial textile standard. Wrinkle resistance tests were conducted according to GB / T3819-1997, "Determination of Crease Recovery of Textile Fabrics - Recovery Angle Method." The wrinkle recovery angle of the core-shell nanoparticle-modified viscose fabric was 129.7°, while that of the unmodified viscose fabric was 110.3°. According to GB / T18830-2009 "Evaluation of Ultraviolet Protection Performance of Textiles", the UPF value of the core-shell nanoparticle modified viscose fabric was 59.14, the UPF value of the unmodified viscose fabric was 16.83, and the UPF value of the modified viscose fabric after 50 washes was 45.36. After 6 hours of xenon lamp irradiation, the oil stains on the surface of the core-shell polymethyl methacrylate@TiO2 nanoparticle modified viscose fabric were basically cleaned. After 3 days of xenon lamp irradiation, the tensile strength of the core-shell polymethyl methacrylate@TiO2 nanoparticle modified viscose fabric decreased by 4.49%.

[0049] Example 2

[0050] (1) Methyl methacrylate monomer and hydroxyethyl acrylate monomer were dissolved in deionized water to prepare a solution with a total mass concentration of 16%, wherein the mass ratio of methyl methacrylate to hydroxyethyl acrylate was 9:1. Nitrogen gas was introduced for 20 min, and azobisisobutyramidine hydrochloride was added to make its mass concentration in the solution 0.4%. Soap-free emulsion polymerization was carried out at 70°C and stirred at 520 r / min for 2 h. After the reaction was completed, the solution was sieved 4 times through a 200 mesh standard sieve to obtain a uniform and stable milky white polymethyl methacrylate microsphere dispersion.

[0051] (2) Add deionized water to the dispersion from step (1) to make the mass concentration of polymethyl methacrylate microspheres 0.12%. Adjust the pH of the solution to 3.0 with 0.03 mol / L dilute hydrochloric acid solution to prepare an anatase phase nano-TiO2 (average particle size 42 nm, Zeta potential 30.57 mV) sol with a mass concentration of 0.14%. Add negatively charged sodium tripolyphosphate (TPP) - Stir and mix evenly to form TiO2 + / TPP - Composite particles were prepared to achieve a mass ratio of sodium tripolyphosphate to anatase nano-TiO2 of 2:1; then, TiO2 was slowly and uniformly added dropwise at a rate of 1.8 mL / min using a constant pressure funnel. + / TPP -The composite particle solution was added to a polymethyl methacrylate (PMMA) microsphere dispersion, maintaining a PMMA to anatase-phase nano-TiO2 mass ratio of 6:1. Simultaneously, a probe-type ultrasonic instrument was used to treat the microspheres at 180W and 30℃ for 45 minutes. This allowed the negatively charged groups (ester groups, hydroxyl groups, etc.) on the surface of the PMMA microspheres, as well as the cationic free radicals from the decomposition of the initiator azobisisobutyramidine hydrochloride, to react with the TiO2. + / TPP - The composite particles generate electrostatic forces, which then electrostatically assemble them into a core-shell polymethyl methacrylate@TiO2 nanoparticle dispersion. The dispersion is then placed in a spray dryer (inlet air temperature of 82℃, water evaporation rate of 20kg / h, outlet air temperature of 35℃, power of 50kW) and dried for 40 minutes to obtain a core-shell polymethyl methacrylate@TiO2 nanoparticle powder with a uniform particle size range of 385nm, a Zeta potential of 36.52mV, and a monodispersity index of 0.241, and a stable core-shell structure.

[0052] (3) The core-shell polymethyl methacrylate@TiO2 nanoparticles obtained in step (2) were ultrasonically dispersed in 1-(3-sulfopropyl)caprolactam hydrogen phosphate ionic liquid to prepare a finishing solution with a mass concentration of 0.4%. Then, green crosslinking agent nano-oxidized chitosan (degree of deacetylation of 94.10%, aldehyde content of C2 and C3 positions of 26.35%, carboxyl content of C6 position of 62.04%, isoelectric point pH=6.0, average particle size of 282nm, and Zeta potential of 31.38mV) was added to make its mass concentration in the finishing solution 0.4%. The pH of the finishing solution was adjusted to 4.5 by adding 0.1mol / L HCl solution dropwise.

[0053] The wool fabric was immersed in a NaHCO3 solution with a mass concentration of 12 g / L at 85°C for 40 min, then ultrasonically cleaned with anhydrous ethanol until neutral, dried, and then placed in a high-density microwave plasma treatment instrument with a microwave power of 1100 W and a microwave frequency of 2.45 GHz. Air was introduced and glow discharge was performed at a vacuum degree of 46 Pa for 5 min. Air was then introduced for another 15 min to obtain the pretreated wool fabric.

[0054] The pretreated wool fabric was placed in the finishing solution at a bath ratio of 1g:50mL and stirred at 35℃ for 2h under microwave radiation with a power of 240W. The wool fabric was then removed and soaked in a mixture of anhydrous ethanol and deionized water with a volume ratio of 1:1 to remove the 1-(3-sulfopropyl)caprolactam hydrogen phosphate ionic liquid. The wool fabric was then placed in a supercritical carbon dioxide dryer with a power of 2.5kW, a working pressure of 1600psi, a drying temperature of -5℃, and a medium flow rate of 800mL / min for 60min. It was then vacuum dried at 40℃ for 1.5h, washed 4 times with deionized water, and air-dried to obtain a multifunctional textile modified with core-shell nanoparticles.

[0055] Antibacterial tests were conducted on core-shell polymethyl methacrylate (PMMA)@TiO2 nanoparticle-modified wool fabrics according to AATCC Test Method 100-1999, "Quantitative Test Methods." The inhibition rate against Staphylococcus aureus was 99.35%, and against Escherichia coli was 99.41%. After 50 washes, it met the AAA-grade antibacterial textile standard. Wrinkle resistance tests were conducted according to GB / T3819-1997, "Determination of Crease Recovery of Textile Fabrics - Recovery Angle Method." The wrinkle recovery angle of the core-shell nanoparticle-modified wool fabric was 213.2°, while that of the unmodified wool fabric was 178.4°. UV protection tests were conducted according to GB / T18830-2009, "Evaluation of Ultraviolet Protection Performance of Textiles." The UPF value of the core-shell nanoparticle-modified wool fabric was 77.35, while that of the unmodified wool fabric was 23.07. After 50 washes, the UPF value of the modified wool fabric was 50.14. After 5 hours of xenon lamp irradiation, the oil stains on the surface of the core-shell polymethyl methacrylate@TiO2 nanoparticle modified wool fabric were basically cleaned. After 3 days of xenon lamp irradiation, the tensile strength of the core-shell polymethyl methacrylate@TiO2 nanoparticle modified wool fabric decreased by 5.36%.

[0056] Example 3

[0057] (1) Methyl methacrylate monomer and hydroxyethyl acrylate monomer were dissolved in deionized water to prepare a solution with a total mass concentration of 20%, wherein the mass ratio of methyl methacrylate to hydroxyethyl acrylate was 6:1. Nitrogen gas was introduced for 25 min, and azobisisobutyramidine hydrochloride was added to make its mass concentration in the solution 0.6%. Soap-free emulsion polymerization was carried out at 75°C with stirring at 620 r / min for 3 h. After the reaction was completed, the solution was sieved 5 times with a 200 mesh standard sieve to obtain a uniform and stable milky white polymethyl methacrylate microsphere dispersion.

[0058] (2) Add deionized water to the dispersion from step (1) to make the mass concentration of polymethyl methacrylate microspheres 0.16%. Adjust the pH of the solution to 3.2 with 0.03 mol / L dilute hydrochloric acid solution to prepare an anatase phase nano-TiO2 sol (average particle size 35 nm, Zeta potential 38.22 mV) with a mass concentration of 0.16%. Add negatively charged sodium tripolyphosphate (TPP) - Stir and mix evenly to form TiO2 + / TPP - Composite particles were prepared to achieve a mass ratio of sodium tripolyphosphate to anatase nano-TiO2 of 4:1; then, TiO2 was slowly and uniformly added dropwise at a rate of 2.0 mL / min using a constant pressure funnel. + / TPP - The composite particle solution was added to a polymethyl methacrylate (PMMA) microsphere dispersion, maintaining a PMMA to anatase-phase nano-TiO2 mass ratio of 4:1. Simultaneously, a probe-type ultrasonic instrument was used to treat the microspheres at 200W and 35℃ for 50 minutes. This allowed the negatively charged groups (ester groups, hydroxyl groups, etc.) on the surface of the PMMA microspheres, as well as the cationic free radicals from the decomposition of the initiator azobisisobutyramidine hydrochloride, to react with the TiO2. + / TPP - The composite particles generate electrostatic forces, which then electrostatically assemble them into a core-shell polymethyl methacrylate@TiO2 nanoparticle dispersion. The dispersion is then placed in a spray dryer (inlet air temperature of 85℃, water evaporation rate of 24kg / h, outlet air temperature of 40℃, and power of 58kW) and dried for 40 minutes to obtain a core-shell polymethyl methacrylate@TiO2 nanoparticle powder with a uniform particle size range of 408nm, a Zeta potential of 43.16mV, and a monodispersity index of 0.127, and a stable core-shell structure.

[0059] (3) The core-shell polymethyl methacrylate@TiO2 nanoparticles obtained in step (2) were ultrasonically dispersed in 1-hydroxyethyl-3-methylimidazolium hydrochloride ionic liquid to prepare a finishing solution with a mass concentration of 0.5%. Then, green crosslinking agent nano-oxidized chitosan (deacetylation degree of 95.26%, aldehyde content of C2 and C3 positions of 28.14%, carboxyl content of C6 position of 68.84%, isoelectric point pH=5.8, average particle size of 245nm, and Zeta potential of 36.51mV) was added to make its mass concentration in the finishing solution 0.4%. The pH of the finishing solution was adjusted to 4.5 by adding 0.1mol / L HCl solution dropwise.

[0060] The degummed silk fabric was immersed in a 12 g / L NaHCO3 solution at 85°C for 50 min, then ultrasonically cleaned with anhydrous ethanol until neutral, and dried. The fabric was then placed in a high-density microwave plasma treatment instrument with a microwave power of 1150 W and a microwave frequency of 2.45 GHz, and air was introduced. Glow discharge was performed at a vacuum degree of 50 Pa for 6 min, and air was introduced for another 16 min to obtain the pretreated silk fabric.

[0061] The pretreated silk fabric was placed in the finishing solution at a bath ratio of 1g:50mL and stirred at 40℃ for 3h under microwave radiation with a power of 280W. The silk fabric was then removed and soaked in a mixture of anhydrous ethanol and deionized water with a volume ratio of 1:1 to remove the 1-hydroxyethyl-3-methylimidazolium hydrochloride ionic liquid. The silk fabric was then placed in a supercritical carbon dioxide dryer with a power of 3.2kW, a working pressure of 1800psi, a drying temperature of -2℃, and a medium flow rate of 1000mL / min for 70min. It was then vacuum dried at 40℃ for 1.5h, washed 5 times with deionized water, and air-dried to obtain a multifunctional textile modified with core-shell nanoparticles.

[0062] Antibacterial tests were conducted on core-shell polymethyl methacrylate (PMMA)@TiO2 nanoparticle-modified silk fabrics according to AATCC Test Method 100-1999, "Quantitative Test Methods." The inhibition rate against Staphylococcus aureus was 99.67%, and against Escherichia coli was 99.96%. After 50 washes, it met the AAA-grade antibacterial textile standard. Wrinkle resistance tests were conducted according to GB / T3819-1997, "Determination of Crease Recovery of Textile Fabrics - Recovery Angle Method." The wrinkle recovery angle of the core-shell nanoparticle-modified silk fabric was 162.4°, while that of the unmodified silk fabric was 133.5°. According to GB / T18830-2009 "Evaluation of Ultraviolet Protection Performance of Textiles", the UPF value of the core-shell nanoparticle modified silk fabric was 121.26, the UPF value of the unmodified silk fabric was 21.30, and the UPF value of the modified silk fabric after 50 washes was 93.08. After 4.5 hours of xenon lamp irradiation, the oil stains on the surface of the core-shell polymethyl methacrylate@TiO2 nanoparticle modified silk fabric were basically cleaned. After 3 days of xenon lamp irradiation, the tensile strength of the core-shell polymethyl methacrylate@TiO2 nanoparticle modified silk fabric decreased by 3.05%.

[0063] Example 4

[0064] (1) Methyl methacrylate monomer and hydroxyethyl acrylate monomer were dissolved in deionized water to prepare a solution with a total mass concentration of 25%, wherein the mass ratio of methyl methacrylate to hydroxyethyl acrylate was 3:1. Nitrogen gas was introduced for 25 min, and azobisisobutyramidine hydrochloride was added to make its mass concentration in the solution 1.0%. Soap-free emulsion polymerization was carried out at 80°C and stirred at 700 r / min for 4 h. After the reaction was completed, the solution was sieved 5 times through a 200 mesh standard sieve to obtain a uniform and stable milky white polymethyl methacrylate microsphere dispersion.

[0065] (2) Add deionized water to the dispersion from step (1) to make the mass concentration of polymethyl methacrylate microspheres 0.2%. Adjust the pH of the solution to 3.5 with 0.03 mol / L dilute hydrochloric acid solution to prepare an anatase phase nano-TiO2 sol (average particle size 35 nm, Zeta potential 38.22 mV) with a mass concentration of 0.16%. Add negatively charged sodium tripolyphosphate (TPP) - Stir and mix evenly to form TiO2 + / TPP - Composite particles were prepared to achieve a mass ratio of sodium tripolyphosphate to anatase nano-TiO2 of 6:1; then, TiO2 was slowly and uniformly added dropwise at a rate of 2.2 mL / min using a constant pressure funnel. + / TPP - The composite particle solution was added to a polymethyl methacrylate (PMMA) microsphere dispersion, maintaining a PMMA to anatase-phase nano-TiO2 mass ratio of 2:1. Simultaneously, a probe-type ultrasonic instrument was used to treat the microspheres at 220W and 40℃ for 50 minutes. This allowed the negatively charged groups (ester groups, hydroxyl groups, etc.) on the surface of the PMMA microspheres, as well as the cationic free radicals from the decomposition of the initiator azobisisobutyramidine hydrochloride, to react with the TiO2. + / TPP - The composite particles generate electrostatic forces, which then electrostatically assemble them into a core-shell polymethyl methacrylate@TiO2 nanoparticle dispersion. The dispersion is then placed in a spray dryer (inlet air temperature of 90℃, water evaporation rate of 26kg / h, outlet air temperature of 40℃, power of 62kW) and dried for 40 minutes to obtain polymethyl methacrylate@TiO2 nanoparticle powder with uniform particle size range of 457nm, Zeta potential of 40.14mV, and monodispersity index of 0.193 and stable core-shell structure.

[0066] (3) The core-shell polymethyl methacrylate@TiO2 nanoparticles obtained in step (2) were ultrasonically dispersed in 3-N,N,N-trimethylammonium propanesulfonic acid ammonium bisulfate ionic liquid to prepare a finishing solution with a mass concentration of 0.5%. Then, green crosslinking agent nano-oxidized chitosan (degree of deacetylation of 96.41%, aldehyde content of C2 and C3 positions of 29.05%, carboxyl content of C6 position of 70.11%, isoelectric point pH=5.8, average particle size of 271nm, and Zeta potential of 33.54mV) was added to make its mass concentration in the finishing solution 0.5%. The pH of the finishing solution was adjusted to 4.8 by adding 0.1mol / L HCl solution dropwise.

[0067] A 40% degummed silk / 60% polyester blended fabric was immersed in a 15 g / L NaHCO3 solution at 88°C for 60 min, then ultrasonically cleaned with anhydrous ethanol until neutral, and dried. The blended fabric was then placed in a high-density microwave plasma treatment instrument with a microwave power of 1200 W and a microwave frequency of 2.45 GHz, and air was introduced. Glow discharge was performed at a vacuum degree of 54 Pa for 6 min, followed by air introduction for another 16 min, to obtain a pretreated 40% degummed silk / 60% polyester blended fabric.

[0068] The pretreated blended fabric was placed in the finishing solution at a bath ratio of 1g:50mL and stirred at 40℃ for 3h under microwave radiation with a power of 300W. The blended fabric was then removed and soaked in a mixture of anhydrous ethanol and deionized water with a volume ratio of 1:1 to remove the ionic liquid of 3-N,N,N-trimethylammonium propanesulfonic acid ammonium bisulfate. The blended fabric was then placed in a supercritical carbon dioxide dryer with a power of 3.5kW, a working pressure of 2000psi, a drying temperature of -2℃, and a medium flow rate of 1050mL / min for 75min. It was then vacuum dried at 40℃ for 2h, washed 5 times with deionized water, and air-dried to obtain a multifunctional textile modified with core-shell nanoparticles.

[0069] Antibacterial tests were conducted on a 40% degummed silk / 60% polyester blended fabric modified with core-shell polymethyl methacrylate@TiO2 nanoparticles according to AATCC Test Method 100-1999, "Quantitative Test Methods." The fabric showed an inhibition rate of 99.39% against Staphylococcus aureus and 99.52% against Escherichia coli. After 50 washes, it met the AAA-grade antibacterial textile standard. Wrinkle resistance tests were performed according to GB / T3819-1997, "Determination of Crease Recovery of Textile Fabrics - Recovery Angle Method." The wrinkle recovery angle of the core-shell nanoparticle-modified blended fabric was 278.7°, while that of the unmodified blended fabric was 236.3°. According to GB / T18830-2009 "Evaluation of Ultraviolet Protection Performance of Textiles", the UPF value of the core-shell nanoparticle modified blended fabric was 80.68, the UPF value of the unmodified blended fabric was 26.45, and the UPF value of the modified silk fabric after 50 washes was 55.72. After 5 hours of xenon lamp irradiation, the oil stains on the surface of the core-shell polymethyl methacrylate@TiO2 nanoparticle modified blended fabric were basically cleaned. After 3 days of xenon lamp irradiation, the tensile strength of the core-shell polymethyl methacrylate@TiO2 nanoparticle modified blended fabric decreased by 4.22%.

[0070] Comparative Example 1 (Ungrafted core-shell polymethyl methacrylate@TiO2 nanoparticles)

[0071] Preparation of pretreated silk fabrics:

[0072] The degummed silk fabric was immersed in a 12 g / L NaHCO3 solution at 85°C for 50 min, then ultrasonically cleaned with anhydrous ethanol until neutral, and dried. The fabric was then placed in a high-density microwave plasma treatment instrument with a microwave power of 1150 W and a microwave frequency of 2.45 GHz, and air was introduced. Glow discharge was performed at a vacuum degree of 50 Pa for 6 min, and air was introduced for another 16 min to obtain the pretreated silk fabric.

[0073] Antibacterial tests were conducted on the pretreated silk fabric according to AATCC Test Method 100-1999, "Quantitative Test Methods." The inhibition rate against Staphylococcus aureus was 41.62%, and against Escherichia coli was 26.85%. Wrinkle resistance tests were conducted according to GB / T3819-1997, "Determination of Crease Recovery of Textile Fabrics - Recovery Angle Method," and the crease recovery angle of the pretreated silk fabric was 133.5°. UV protection tests were conducted according to GB / T18830-2009, "Evaluation of Ultraviolet Protection Performance of Textiles," and the UPF value of the pretreated silk fabric was 21.30. After 12 hours of xenon lamp irradiation, the oil stains on the surface of the pretreated silk fabric remained essentially unchanged. After 3 days of xenon lamp irradiation, the tensile strength of the pretreated silk fabric decreased by 3.54%.

[0074] Comparative Example 2 (without the addition of hydroxyethyl acrylate monomer and without high-density microwave plasma treatment)

[0075] (1) Dissolve methyl methacrylate monomer in deionized water to prepare a solution with a total mass concentration of 20%. Purge with nitrogen for 25 min, add initiator azobisisobutyramidine hydrochloride to make its mass concentration in the solution 0.6%, and carry out soap-free emulsion polymerization reaction at 75°C and 620 r / min for 3 h. After the reaction is completed, sieve through a 200 mesh standard sieve 5 times to obtain a uniform and stable milky white polymethyl methacrylate microsphere dispersion.

[0076] (2) Add deionized water to the dispersion from step (1) to make the mass concentration of polymethyl methacrylate microspheres 0.16%. Adjust the pH of the solution to 3.2 with 0.03 mol / L dilute hydrochloric acid solution to prepare an anatase phase nano-TiO2 sol (average particle size 35 nm, Zeta potential 38.22 mV) with a mass concentration of 0.16%. Add negatively charged sodium tripolyphosphate (TPP) - Stir and mix evenly to form TiO2 + / TPP - Composite particles were prepared to achieve a mass ratio of sodium tripolyphosphate to anatase nano-TiO2 of 4:1; then, TiO2 was slowly and uniformly added dropwise at a rate of 2.0 mL / min using a constant pressure funnel. + / TPP - The composite particle solution was added to a polymethyl methacrylate (PMMA) microsphere dispersion, maintaining a PMMA to anatase-phase nano-TiO2 mass ratio of 4:1. Simultaneously, a probe-type ultrasonic instrument was used to treat the microspheres at 200W and 35℃ for 50 minutes. This allowed the negatively charged groups (ester groups, hydroxyl groups, etc.) on the surface of the PMMA microspheres, as well as the cationic free radicals from the decomposition of the initiator azobisisobutyramidine hydrochloride, to react with the TiO2. + / TPP - The composite particles generate electrostatic forces, which then electrostatically assemble them into a core-shell polymethyl methacrylate@TiO2 nanoparticle dispersion. The dispersion is then placed in a spray dryer (inlet air temperature of 85℃, water evaporation rate of 24kg / h, outlet air temperature of 40℃, power of 58kW) and dried for 40 minutes to obtain polymethyl methacrylate@TiO2 nanoparticle powder with a particle size range of 374nm, a Zeta potential of 31.08mV, and a monodispersity index of 0.302.

[0077] (3) The core-shell polymethyl methacrylate@TiO2 nanoparticles obtained in step (2) were ultrasonically dispersed in 1-hydroxyethyl-3-methylimidazolium hydrochloride ionic liquid to prepare a finishing solution with a mass concentration of 0.5%. Then, green crosslinking agent nano-oxidized chitosan (deacetylation degree of 95.26%, aldehyde content of C2 and C3 positions of 28.14%, carboxyl content of C6 position of 68.84%, isoelectric point pH=5.8, average particle size of 245nm, and Zeta potential of 36.51mV) was added to make its mass concentration in the finishing solution 0.4%. The pH of the finishing solution was adjusted to 4.5 by adding 0.1mol / L HCl solution dropwise.

[0078] The degummed silk fabric was immersed in a NaHCO3 solution with a mass concentration of 12 g / L at 85°C for 50 min, and then ultrasonically cleaned with anhydrous ethanol until neutral to obtain the pretreated silk fabric.

[0079] The pretreated silk fabric was placed in the finishing solution at a bath ratio of 1g:50mL and stirred at 40℃ for 3h under microwave radiation with a power of 280W. The silk fabric was then removed and soaked in a mixture of anhydrous ethanol and deionized water with a volume ratio of 1:1 to remove the 1-hydroxyethyl-3-methylimidazolium hydrochloride ionic liquid. The silk fabric was then placed in a supercritical carbon dioxide dryer with a power of 3.2kW, a working pressure of 1800psi, a drying temperature of -2℃, and a medium flow rate of 1000mL / min for 70min. It was then vacuum dried at 40℃ for 1.5h, washed 5 times with deionized water, and air-dried to obtain a multifunctional textile modified with core-shell nanoparticles.

[0080] Antibacterial tests were conducted on core-shell polymethyl methacrylate (PMMA)@TiO2 nanoparticle-modified silk fabrics according to AATCC Test Method 100-1999, "Quantitative Test Methods." The inhibition rate against Staphylococcus aureus was 97.04%, and against Escherichia coli was 95.73%. After 50 washes, it met the AA-grade antibacterial textile standard. Wrinkle resistance tests were conducted according to GB / T3819-1997, "Determination of Crease Recovery of Textile Fabrics - Recovery Angle Method." The wrinkle recovery angle of the core-shell nanoparticle-modified silk fabric was 153.7°, while that of the unmodified silk fabric was 133.5°. According to GB / T18830-2009 "Evaluation of Ultraviolet Protection Performance of Textiles", the UPF value of the core-shell nanoparticle modified silk fabric was 66.25, the UPF value of the unmodified silk fabric was 21.30, and the UPF value of the modified silk fabric after 50 washes was 41.13. After 8 hours of xenon lamp irradiation, the oil stains on the surface of the core-shell polymethyl methacrylate@TiO2 nanoparticle modified silk fabric were basically cleaned. After 3 days of xenon lamp irradiation, the tensile strength of the core-shell polymethyl methacrylate@TiO2 nanoparticle modified silk fabric decreased by 3.64%.

[0081] Comparative Example 3 (Silk Fabric Treated with Nano TiO2)

[0082] (1) Prepare an anatase phase nano-TiO2 sol with a mass concentration of 0.16% (average particle size of 35nm, Zeta potential of 38.22mV) and adjust the pH of the sol to 3.2 with 0.03mol / L dilute hydrochloric acid solution.

[0083] (2) The anatase phase nano-TiO2 sol obtained in step (1) was ultrasonically dispersed in 1-hydroxyethyl-3-methylimidazolium hydrochloride ionic liquid to prepare a finishing solution with a mass concentration of 0.5%. Then, the pH of the finishing solution was adjusted to 4.5 by adding 0.1 mol / L HCl solution.

[0084] The degummed silk fabric was immersed in a 12 g / L NaHCO3 solution at 85°C for 50 min, then ultrasonically cleaned with anhydrous ethanol until neutral, and dried. The fabric was then placed in a high-density microwave plasma treatment instrument with a microwave power of 1150 W and a microwave frequency of 2.45 GHz, and air was introduced. Glow discharge was performed at a vacuum degree of 50 Pa for 6 min, and air was introduced for another 16 min to obtain the pretreated silk fabric.

[0085] The pretreated silk fabric was placed in the finishing solution at a bath ratio of 1g:50mL and stirred at 40℃ for 3h under microwave radiation with a power of 280W. The silk fabric was then removed and soaked in a mixture of anhydrous ethanol and deionized water with a volume ratio of 1:1 to remove the 1-hydroxyethyl-3-methylimidazolium hydrochloride ionic liquid. The silk fabric was then placed in a supercritical carbon dioxide dryer with a power of 3.2kW, a working pressure of 1800psi, a drying temperature of -2℃, and a medium flow rate of 1000mL / min for 70min. It was then vacuum dried at 40℃ for 1.5h, washed 5 times with deionized water, and air-dried to obtain a multifunctional textile modified with core-shell nanoparticles.

[0086] Antibacterial tests were conducted on nano-TiO2 modified silk fabrics according to AATCC Test Method 100-1999, "Quantitative Test Methods." The inhibition rate against Staphylococcus aureus was 97.83%, and against Escherichia coli was 99.01%. After 50 washes, it meets the AA-grade antibacterial textile standard. Wrinkle resistance tests were conducted according to GB / T3819-1997, "Determination of Crease Recovery of Textile Fabrics - Recovery Angle Method." The wrinkle recovery angle of the nano-TiO2 modified silk fabric was 149.3°, while that of the unmodified silk fabric was 133.5°. UV protection tests were conducted according to GB / T18830-2009, "Evaluation of Ultraviolet Protection Performance of Textiles." The UPF value of the nano-TiO2 modified silk fabric was 70.74, compared to 21.30 for the unmodified silk fabric. After 50 washes, the UPF value of the modified silk fabric was 37.19. After 5 hours of xenon lamp irradiation, the oil stains on the surface of the nano-TiO2 modified silk fabric were basically cleaned. After 3 days of xenon lamp irradiation, the tensile strength of the nano-TiO2 modified silk fabric decreased by 28.25%.

[0087] II. Testing the samples obtained in the above embodiments.

[0088] Test Item 1: Oil Stain Decomposition Test of Multifunctional Textiles Modified with Core-Shell Nanoparticles

[0089] Three silk fabric samples were taken: the first sample was fabric A, obtained by pretreating silk fabric according to the method of Comparative Example 1; the second sample was modified fabric B, obtained by treating silk fabric according to the method of Comparative Example 2; and the third sample was modified fabric C, obtained by treating silk fabric according to the method of Example 3. A drop of red oil was placed on the surface of each silk fabric sample using a dropper. Then, the silk fabric with the red oil adhering to it was irradiated with a xenon lamp with a wavelength range of 200–600 nm and a power of 100 W. The K / S value of the core-shell nanoparticle modified silk fabric sample with the oil adhering to it was measured at the maximum absorption wavelength of 460 nm using a colorimeter under different irradiation times. The K / S value of the fabric can represent the ability of the modified fabric to decompose oil stains. The lower the K / S value, the better the self-cleaning performance of the modified silk fabric. The test results are shown in Table 1.

[0090] Table 1. K / S values ​​of core-shell nanoparticle-modified silk fabrics after different light exposure times.

[0091]

[0092] As shown in Table 1, the red oil stains on the pretreated silk fabric surface only diffused and penetrated inwards, causing the oil stain color on the fabric surface to lighten until it stabilized, but it had no ability to decompose the oil stains. The K / S value after 8 hours of xenon lamp irradiation was still around 2.63, and the oil stains on the fabric surface did not change. However, the K / S values ​​of silk fabrics B and C modified with core-shell polymethyl methacrylate@TiO2 nanoparticles decreased significantly after 4 hours of light irradiation, and the K / S value decreased even more after 6 hours of light irradiation, indicating that the core-shell polymethyl methacrylate@TiO2 nanoparticle modified silk fabric has strong self-cleaning oil stain performance. Meanwhile, compared with modified silk fabric B, modified silk fabric C has a smaller K / S value after being exposed to light for different times, and a stronger ability to decompose oil stains. This is because the core-shell nanoparticles used in modified silk fabric B lack hydroxyethyl acrylate monomer, which reduces the negatively charged groups such as carboxyl and ester groups on the surface of polymethyl methacrylate microspheres. The number of positively charged TiO2 nanoparticles electrostatically bonded to the surface of the core-shell microparticles is also smaller, affecting the photocatalytic activity. In addition, modified silk fabric B did not undergo microwave plasma pretreatment, and no oxygen-containing active groups were introduced into the silk surface. The modified silk fabric has fewer grafted core-shell nanoparticles, which affects the photodynamic decomposition effect of the modified fabric on oil stains. The modified silk fabric C uses core-shell nanoparticles with added hydroxyethyl acrylate monomer. The polymethyl methacrylate microspheres formed by copolymerizing hydroxyethyl acrylate and methyl methacrylate have a high content of negatively charged carboxyl groups on their surface, which enhances the electrostatic attraction to positively charged TiO2 particles. At the same time, the silk surface treated with microwave plasma introduces oxygen-containing polar groups such as carboxyl and carbonyl groups, which significantly improves the grafting efficiency of core-shell nanoparticles. Furthermore, the microwave plasma treatment produces etching and roughness on the silk surface, which increases the bonding strength of core-shell nanoparticles to the silk surface. As a result, the modified silk fabric exhibits highly efficient self-cleaning oil stain ability.

[0093] In summary, this invention reacts a core-shell polymethyl methacrylate (PMMA)@TiO2 nanoparticle ionic liquid solution with fabric. Through ionic liquid catalysis, the aldehyde and carboxyl groups in the green crosslinking agent nano-oxidized chitosan particles form Schiff bases, amide bonds, and acetal bonds with the amino and hydroxyl groups in the fabric, resulting in multi-site grafting of the PMMA nanoparticles onto the fabric surface. The PMMA nanoparticles are uniformly distributed in the fabric, exhibiting strong stability, high efficiency and long-lasting functionality, and good washability. Furthermore, the grafting of the green crosslinking agent nano-oxidized chitosan onto the fabric surface effectively prevents the TiO2 in the PMMA@TiO2 nanoparticles from photo-eroding the textile substrate, without affecting the textile's mechanical, hand feel, breathability, and other performance properties. The preparation process of this invention is simple and easy to implement, low in cost, with mild and controllable reaction conditions, and does not use any toxic additives, making it environmentally friendly. The resulting PMMA@TiO2 nanoparticle-grafted fabric is soft, moisture-wicking, breathable, and skin-friendly, providing comfortable wear. It also offers long-lasting antibacterial, wrinkle-resistant, UV-protective, and self-cleaning functions, demonstrating broad market application prospects.

[0094] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A core-shell nanoparticle modified multifunctional textile, characterized in that: The core-shell type nano-particle modified multifunctional textile is obtained by the reaction of the core-shell type polymethyl methacrylate@TiO2 nano-particle ionic liquid solution with the fabric, and the formation of Schiff base, amide bond and acetal bond by the ionic liquid catalyzed green crosslinking agent nano-oxidized chitosan particles aldehyde group and carboxyl group in the fabric amino group and hydroxyl group, so that the core-shell type polymethyl methacrylate@TiO2 nano-particle is grafted on the fabric surface in multiple sites; the core-shell type polymethyl methacrylate@TiO2 nano-particle is obtained by the following method: (1) methyl methacrylate monomer and hydroxyethyl acrylate monomer are dissolved in deionized water to prepare a solution with a total mass concentration of 10-35%, nitrogen is introduced for 15-30 min, initiator azobisdimethylaminoformamide hydrochloride is added to make its mass concentration in the solution 0.2-1.2%, and the solution is stirred at a speed of 250-800 r / min at 60-85℃ for 2-5 h to carry out soap-free emulsion polymerization reaction, and after the reaction is completed, the solution is screened 3-5 times with a 200 mesh standard screen to obtain a uniform and stable milky white polymethyl methacrylate microsphere dispersion liquid; the mass ratio of methyl methacrylate to hydroxyethyl acrylate is 1-12:1; (2) adding deionized water to the dispersion liquid of step (1) to make the mass concentration of polymethyl methacrylate microspheres 0.08-0.25%, adjusting the solution pH to 2.6-3.8 with 0.03 mol / L dilute hydrochloric acid solution; preparing anatase nano-TiO2 sol with a mass concentration of 0.1-0.2%, and adding negatively charged sodium tripolyphosphate TPP - stirring and mixing uniformly to form TiO2 + / TPP - composite particles; then slowly and uniformly adding TiO2 + / TPP - composite particle solution to the polymethyl methacrylate microsphere dispersion liquid at a speed of 1.2-2.6 mL / min, and simultaneously starting a probe-type ultrasonic instrument to treat at 100-280 W, 25-40°C for 30-60 min, so that the negative groups on the surface of the polymethyl methacrylate microspheres and the cationic radicals after decomposition of the initiator azobisdimethylamidinium hydrochloride are respectively combined with TiO2 + / TPP - composite particles to generate electrostatic force, and further electrostatically assembled into core-shell type polymethyl methacrylate@TiO2 nanoparticle dispersion liquid; and then drying the dispersion liquid in a spray dryer for 25-45 min to obtain core-shell type polymethyl methacrylate@TiO2 nanoparticle powder; the mass ratio of the polymethyl methacrylate to the anatase nano-TiO2 is 2-8:1; and the mass ratio of the sodium tripolyphosphate to the anatase nano-TiO2 is 1-6:

1.

2. A multi-functional textile modified with core-shell type nanoparticles as claimed in claim 1, wherein: The average particle size of the anatase phase nano-TiO2 is 32-50 nm, and the Zeta potential is 28.66-40.19 mV; the particle size of the core-shell type polymethyl methacrylate@TiO2 nano-particle is 315-520 nm, the Zeta potential is 30.24-47.93 mV, and the monodisperse coefficient is 0.116-0.

307.

3. The multi-functional textile modified with core-shell type nanoparticles according to claim 1, characterized in that: The air inlet temperature of the spray dryer is 75-100℃, the water evaporation amount is 10-32 kg / h, the air outlet temperature is 30-45℃, and the power is 30-76 kW.

4. The multi-functional textile modified with core-shell type nanoparticles according to claim 1, characterized in that: The fabric is a natural fiber or chemical fiber fabric or a blended fabric of the two.

5. A method for preparing the multi-functional textile modified with the core-shell nanoparticle according to any one of claims 1 to 4, characterized by: The core-shell type polymethyl methacrylate@TiO2 nano-particle is ultrasonically dispersed in the ionic liquid to prepare a finishing liquid with a mass concentration of 0.2-0.8%, and then a green crosslinking agent nano-oxidized chitosan is added to make its mass concentration in the finishing liquid 0.2-0.6%, and the pH of the finishing liquid is adjusted to 4.0-5.2 by adding 0.1 mol / L HCl solution dropwise; The fabric is immersed in a NaHCO3 solution with a mass concentration of 10-15 g / L at 80-90℃ for 30-60 min, and then ultrasonically cleaned with anhydrous ethanol until neutral, and the dried fabric is placed in a high-density microwave plasma treatment instrument, air is introduced, and the vacuum degree is 30-62 Pa, the glow discharge is carried out for 3-8 min, and then air is continuously introduced for 12-18 min to obtain the pretreated fabric. The pretreated fabric is put into the finishing liquid with a bath ratio of 1g:50mL, and is stirred and reacted at 30-45 DEG C under microwave radiation with a power of 180-350W for 1-3h, then the fabric is taken out, soaked in a mixture of anhydrous ethanol and deionized water with a volume ratio of 1:1 to remove the ionic liquid, and then the fabric is put into a supercritical carbon dioxide drying machine for 45-90min, and vacuum dried at 40 DEG C for 1-2h, and after washing with deionized water for 3-5 times and air drying, a multi-functional textile modified by core-shell type nano-particles is obtained.

6. The method of claim 5, wherein: The deacetylation degree of the nano-oxidized chitosan is greater than or equal to 91.62%, the content of aldehyde groups at C2 and C3 is 21.18-30.49%, the content of carboxyl groups at C6 is 52.36-75.51%, the isoelectric point is pH=5.8-6.1, the average particle size is 185-316nm, and the Zeta potential is 27.13-38.54mV; the structural formula of the nano-oxidized chitosan is as follows: 。 7. The method of claim 5, wherein: The ionic liquid is selected from 1-ethyl acetate-3-methyl imidazole tetrafluoroborate, 1-(3-sulfopropyl) caprolactam hydrogen sulfate, 1-(3-sulfopropyl) caprolactam hydrogen phosphate, 3-N,N,N-trimethyl ammonium propyl sulfonic acid ammonium hydrogen sulfate, 1-hydroxyethyl-3-methyl imidazole hydrochloride, 1-hydroxyethyl-3-butyl imidazole hydrochloride or 1-carboxymethyl-3-methyl imidazole hydrochloride.

8. The method of claim 5, wherein: The microwave power of the high-density microwave plasma processor is 850-1260W, and the microwave frequency is 2.45GHz.

9. The method of claim 5, wherein: The power of the supercritical carbon dioxide drying machine is 1.5-4.6kW, the working pressure is 800-2500psi, the drying temperature is -30-40 DEG C, and the medium flow rate is 500-1200mL / min.

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