Negative ion enhanced antibacterial polymer fiber and preparation method thereof

Abstract

The invention discloses a negative ion enhanced antibacterial polymer fiber and a preparation method thereof, belongs to the technical field of fiber preparation, and is used for solving the technical problem that the antibacterial property and the tensile property of the antibacterial polymer fiber in the prior art need to be further improved. The method comprises the following steps: carrying out surface modification on modified acrylic fibers to obtain the antibacterial acrylic fibers, namely hybridizing an organic chain segment structure in acrylonitrile and methyl acrylate processes by preparing and using an antibacterial chain extender to obtain modified polyacrylonitrile, and carrying out melt spinning on the modified polyacrylonitrile and auxiliary materials to obtain the acrylic fibers, after ester groups on acrylic fibers are ammoniated through 4-allyl piperazine-1-amine, a double-bond structure is introduced, a phosphorus material is introduced through phosphorus-hydrogen addition, finally, quaternary ammonium salt and phosphonium salt are introduced to the surfaces of the fibers through bromoethane modification, and the high-performance antibacterial acrylic fibers are obtained.

Description

Technical Field

[0001] The present invention relates to the technical field of fiber preparation, and particularly relates to an antibacterial polymer fiber enhanced with negative ions and a preparation method thereof. Background Art

[0002] Initially, antibacterial fibers mainly relied on natural materials such as cotton and silk, and achieved basic antibacterial functions by soaking in solutions containing silver or copper. Their applications were mostly seen in the medical and textile fields.

[0003] In the mid-20th century, with the rise of synthetic fibers, materials such as polyester and nylon gradually became the mainstream. The antibacterial property was improved by physically adsorbing or chemically bonding metal ions, but the durability and safety were limited.

[0004] Entering the 21st century, nanotechnology has promoted the innovation of antibacterial fibers. The introduction of nanomaterials such as silver nanoparticles and titanium dioxide has significantly improved the antibacterial efficiency, and the fiber structure has been optimized through electrospinning and coating processes, expanding the application scope.

[0005] In the future, antibacterial fibers are expected to combine with intelligent technologies to develop fibers with self-adaptive antibacterial or controlled-release functions, meeting the growing needs in the medical, textile, and industrial fields, and promoting the industry to move towards high performance and sustainability.

[0006] For example, the prior art CN108716115B discloses an antibacterial fiber, a preparation method thereof, and an application, including the following steps: (1) dissolving gelatin in water to obtain solution A; (2) dissolving polyvinyl alcohol in an aqueous solution of dimethyl sulfoxide to obtain solution B; (3) mixing a silver-loaded antibacterial agent and absolute ethanol to obtain dispersion liquid C; (4) mixing solution A and solution B and stirring, adding dispersion liquid C, and mixing evenly to obtain a blend; (5) coating the blend on the fibril and drying. The molecular chain of this antibacterial fiber contains gelatin with abundant hydrophilic groups such as hydroxyl and amino groups, and forms a network space structure through cross-linking with polyvinyl alcohol containing a large number of hydroxyl groups. The surface is dense and uniform, having good water absorption and air permeability. At the same time, nano silver particles are evenly attached to the surface of the fiber, having good antibacterial properties.

[0007] However, in the above patent content, gelatin, polyvinyl alcohol, and a silver-loaded antibacterial agent are introduced on the surface of the fibril to obtain an antibacterial fiber. However, the silver-loaded antibacterial agent only relies on the release of silver ions to achieve sterilization, lacks additional functional modification, and cannot effectively destroy the bacterial cell membrane, resulting in limited antibacterial effects.

[0008] In addition, the coating process does not deeply optimize the molecular structure, the distribution and persistence of the antibacterial agent are poor, and due to the low molecular chain regularity of the gelatin and polyvinyl alcohol blend matrix, the crystallinity and orientation degree are insufficient, and a high-strength microstructure cannot be formed.

[0009] Meanwhile, due to the lack of introduction of inorganic reinforcing fillers, the interfacial bonding force is weak, and the coating process does not form an ordered fiber structure through tensile optimization, resulting in poor overall mechanical properties and difficulty in meeting high-strength requirements. Therefore, the performance of this fiber needs to be further improved. Summary of the Invention

[0010] The purpose of the present invention is to provide a negative ion-enhanced antibacterial polymer fiber and its preparation method to solve the technical problem that the antibacterial performance and tensile resistance of antibacterial polymer fibers in the prior art need to be further improved.

[0011] The purpose of the present invention can be achieved through the following technical solutions: A preparation method of a negative ion-enhanced antibacterial polymer fiber, comprising the following steps:

[0012] S1. Add the composite polyacrylonitrile material to a stirring kettle, raise the temperature of the stirring kettle to 210 - 220 °C, and keep stirring for 10 - 15 min to obtain a melt;

[0013] S2. Perform melt spinning on the melt to obtain modified acrylic fibers;

[0014] S3. Perform surface modification on the modified acrylic fibers to obtain antibacterial acrylic fibers;

[0015] Among them, the composite polyacrylonitrile material comprises the following raw materials by weight: 80 - 100 parts of modified polyacrylonitrile and 12 - 20 parts of auxiliary materials;

[0016] The preparation method of the modified polyacrylonitrile is as follows: Add acrylonitrile, methyl acrylate, and N,N-dimethylformamide to a reaction kettle and stir. After the temperature of the reaction kettle rises to 60 - 80 °C, add azobisisobutyronitrile to the reaction kettle. After keeping stirring for 2 - 3 h, continue to add an antibacterial chain extender, keep stirring for 30 - 40 min, and perform post-treatment to obtain modified polyacrylonitrile.

[0017] The reaction equation for preparing modified polyacrylonitrile is:

[0018]

[0019] In the formula: represents an antibacterial chain extender.

[0020] The reaction principle for preparing modified polyacrylonitrile is: Azobisisobutyronitrile decomposes under heating to generate free radicals. The monomer free radicals of acrylonitrile and methyl acrylate continuously add to form a polymer chain. The free radicals at the end continue to react with amino groups to form an extended chain structure, obtaining modified polyacrylonitrile.

[0021] Further, in step S1, the auxiliary materials include raw materials composed of the following parts by weight: 5-8 parts of antioxidant, 2-4 parts of lubricant, and 5-8 parts of heat stabilizer. Among them, the lubricant is one or more of calcium stearate and polyethylene wax; the antioxidant is one or more of triphenyl phosphite and dilauryl sulfide; the heat stabilizer is one or more of dibutyltin dilaurate and epoxidized soybean oil.

[0022] Further, in the preparation process of the modified polyacrylonitrile, the dosage ratio of acrylonitrile, methyl acrylate, N,N-dimethylformamide, azobisisobutyronitrile, and the antibacterial chain extender is 4-6 g: 2-3 g: 30-36 mL: 0.3-0.4 g: 0.5-0.8 g. The post-treatment includes: after the reaction is completed, the reaction kettle is cooled to room temperature, and the reaction solution is added into a rotary evaporator with a water bath temperature of 80-100 °C, and vacuum distilled until no liquid is extracted to obtain the modified polyacrylonitrile.

[0023] Further, the process of melt spinning is as follows: after the melt is filtered through a 300-500 mesh filter screen, a spinneret with a pore diameter of 0.15-0.30 mm and 200-400 holes is used for spinning. The spinning temperature is 200-210 °C, the extrusion speed is 1.2-1.5 g / min per hole, the side blowing cooling wind speed is 0.3-0.6 m / s, the wind temperature is 15-20 °C, and the relative humidity is 40-60%. The initial draft ratio is 3.0-4.5 times, the draft temperature is 90-110 °C, and the draft speed is 200-300 m / min; the heat setting temperature is 130-150 °C, and the setting time is 0.5-0.8 s; the winding speed is 3600-4000 m / min, and the tension is 0.1-0.2 cN / dtex.

[0024] Further, the preparation method of the antibacterial chain extender includes the following steps:

[0025] A1. Add tourmaline powder, sodium silicate, and deionized water into the reaction kettle and stir. During the stirring process, add silver nitrate solution dropwise to the reaction kettle at a uniform speed, ensuring that the silver nitrate solution is added dropwise within 30-40 min, and continue to stir for 20-30 min. After post-treatment, modified tourmaline is obtained;

[0026] A2. Add the modified tourmaline, 4-aminobutyltriethoxysilane, absolute ethanol, and deionized water into the reaction kettle and stir. After adjusting the pH of the reaction system to 8-10 with saturated sodium hydroxide aqueous solution, the temperature of the reaction kettle is raised to 40-50 °C, and keep stirring for 30-40 min. After post-treatment, the antibacterial chain extender is obtained.

[0027] The reaction principle for preparing the antibacterial chain extender is as follows: The silver nitrate solution is slowly added during stirring. The silver ions undergo chemical adsorption or coordination reactions with the active sites on the surface of tourmaline, fixing the silver ions on the surface of tourmaline to obtain modified tourmaline. The ethoxy groups of 4-aminobutyltriethoxysilane hydrolyze in water, and the generated silanol groups undergo condensation reactions with the silanol or aluminate hydroxyl groups on the surface of the modified tourmaline to form covalent bonds, grafting the aminosilane onto the surface of tourmaline, and finally obtaining the antibacterial chain extender.

[0028] Further, in step A1, the dosage ratio of tourmaline powder, sodium silicate, deionized water, and silver nitrate solution is 4 - 5 g: 5 - 6 g: 70 - 80 mL: 20 - 30 mL. Among them, the silver nitrate solution is obtained by mixing 7 - 8 g of silver nitrate and 20 - 30 mL of deionized water. The post-treatment includes: after the reaction is completed, when the temperature of the reactant system drops to room temperature, filter the reactant system to collect the filter cake. After washing the filter cake 3 - 5 times with absolute ethanol and deionized water, transfer the filter cake to a vacuum drying oven at 80 °C and vacuum dry it to constant weight to obtain the modified tourmaline.

[0029] Further, in step A2, the dosage ratio of modified tourmaline, 4-aminobutyltriethoxysilane, absolute ethanol, and deionized water is 5 - 6 g: 1 - 2 g: 20 - 25 mL: 12 - 15 mL. The post-treatment includes: after the reaction is completed, when the temperature of the reactant system drops to room temperature, filter the reactant system to collect the filter cake. After washing the filter cake 3 - 5 times with absolute ethanol and deionized water, transfer the filter cake to a vacuum drying oven at 80 °C and vacuum dry it to constant weight to obtain the antibacterial chain extender.

[0030] Further, in step S4, the surface modification operation includes the following steps:

[0031] B1. Slowly add the modified acrylic fiber, 4-allylpiperazin-1-amine, and deionized water into a three-necked flask equipped with a thermometer, a stirrer, and a reflux condenser in sequence. Under stirring conditions, heat the three-necked flask to reflux and then keep it refluxing for 5 - 6 h, and perform post-treatment to obtain the amidated acrylic fiber.

[0032] B2. Add the amidated acrylic fiber, diphenylphosphine, chloroplatinic acid, and absolute ethanol into a reaction kettle. Raise the temperature of the reaction kettle to 40 - 50 °C and keep the reaction for 1 - 2 h to obtain the phosphated acrylic fiber.

[0033] B3. Under the protection of nitrogen, add the phosphated acrylic fiber and absolute ethanol into the reaction kettle and stir. Then raise the temperature of the reaction kettle to 40 - 50 °C. After keeping it stirred for 20 - 30 min, add triethylamine to the reactant system, continue to keep it stirred for 10 - 12 min, then add bromoethane solution dropwise to the reactant system, continuously add it dropwise for 1 - 2 h, and keep it stirred for 3 - 4 h, and perform post-treatment to obtain the antibacterial acrylic fiber.

[0034] The reaction equation for preparing antibacterial acrylic fibers is as follows:

[0035]

[0036] In the formula:

[0037] The reaction principle for preparing antibacterial acrylic fibers is as follows: Under heating conditions, 4-allylpiperazin-1-amine ammoniates the modified acrylic fibers and introduces a double bond structure. Then, a phosphorus structure is introduced into the fiber structure by hydrophosphination. Finally, the lone pair electrons of the phosphorus atom attack the carbon atom of ethyl bromide to form new phosphorus-carbon and nitrogen-carbon bonds, while bromide ions are released to generate phosphonium salts and ammonium salts, thereby obtaining antibacterial acrylic fibers.

[0038] Furthermore, in step B1, the dosage ratio of the modified acrylic fibers, 4-allylpiperazin-1-amine, and deionized water is 4 - 5 g : 20 - 24 mL : 12 - 15 mL. The post-treatment includes: After the reaction is completed, when the temperature of the reaction kettle drops to room temperature, the fiber material is taken out, washed 3 - 5 times with absolute ethanol and deionized water, and then the fiber material is transferred to a vacuum drying oven at 80 °C and vacuum dried to constant weight to obtain ammoniated acrylic fibers;

[0039] Furthermore, in step B2, the dosage ratio of ammoniated acrylic fibers, diphenylphosphine, chloroplatinic acid, and absolute ethanol is 4 - 5 g : 0.5 - 0.8 g : 0.1 - 0.2 g : 20 - 24 mL. The post-treatment includes: After the reaction is completed, when the temperature of the reaction kettle drops to room temperature, the fiber material is taken out, washed 3 - 5 times with absolute ethanol and deionized water, and then the fiber material is transferred to a vacuum drying oven at 80 °C and vacuum dried to constant weight to obtain phosphated acrylic fibers;

[0040] Furthermore, in step B3, the dosage ratio of phosphated acrylic fibers, absolute ethanol, triethylamine, and ethyl bromide solution is 3 - 4 g : 20 - 24 mL : 0.5 - 0.8 g : 10 - 12 mL. Among them, the ethyl bromide solution is obtained by mixing ethyl bromide and absolute ethanol according to a dosage ratio of 1 - 2 g : 10 - 12 mL. The post-treatment includes: After the reaction is completed, when the temperature of the reaction kettle drops to room temperature, the fiber material is taken out, washed 3 - 5 times with absolute ethanol and deionized water, and then the fiber material is transferred to a vacuum drying oven at 80 °C and vacuum dried to constant weight to obtain antibacterial acrylic fibers.

[0041] The present invention also provides a negative ion-enhanced antibacterial polymer fiber, which is prepared by using the preparation method of the above-mentioned negative ion-enhanced antibacterial polymer fiber.

[0042] The present invention has the following beneficial effects:

[0043] 1. After the tourmaline is modified with silver silicate and a silane coupling agent, the surface active sites increase, the interaction with air water molecules is enhanced, the generation of negative ions is promoted, and the negative ion release is maintained for a long time after being embedded in the fiber matrix; secondly, the antibacterial chain extender forms a strong antibacterial layer through amino modification and the introduction of quaternary ammonium salts and phosphonium salts. The positive charges of the quaternary ammonium salts and phosphonium salts destroy the charge balance of the bacterial cell membrane, causing the cells to rupture. The slow release of silver ions further inhibits bacterial growth, synergistically improving the antibacterial effect. The quaternary ammonium salts and phosphonium salts interfere with the physiological activities of mites through electrostatic effects, reducing their attachment and reproduction ability. The chemical action of the phosphorus material destroys the metabolism of mites and enhances the mite removal performance. Furthermore, after the modified polyacrylonitrile is melt-spun and functionalized, a multifunctional composite structure is formed on the fiber surface. The negative ion release improves the air quality, the antibacterial performance effectively inhibits pathogens, and the mite removal function reduces the breeding of mites. It has excellent comprehensive performance and is suitable for the field of high-performance textiles.

[0044] 2. The present invention also introduces organic chain segments into the polymerization of acrylonitrile and methacrylate through an antibacterial chain extender to form a hybrid structure, optimize the regularity and intermolecular interaction of the polyacrylonitrile molecular chain, improve the crystallinity and orientation of the fiber, and thus significantly enhance the tensile strength; secondly, the modified tourmaline is uniformly dispersed in the fiber matrix as a high modulus inorganic filler, acting as a reinforcing agent, effectively dispersing external forces, reducing stress concentration, and improving the mechanical properties of the fiber; in addition, the chemical modification of silane coupling agent, quaternary ammonium salt and phosphonium salt enhances the interfacial bonding force between the fiber surface and the matrix, improves the structural stability, and makes the fiber less likely to break or delaminate during stretching; finally, the optimization of the melt spinning process prompts the polymer chain to form a highly ordered microstructure under tensile orientation, so that the fiber exhibits excellent strength and toughness when subjected to tensile force, further enhancing the tensile resistance and making it suitable for high-performance textile applications.

[0045] 3. The modified tourmaline used in the present invention as an inorganic filler has high thermal stability, can absorb heat and form a thermal insulation layer, slowing down the thermal decomposition and combustion process of the fiber; secondly, the phosphorus material introduced by phosphorus-hydrogen addition generates a coke layer containing phosphoric acid at high temperature. This carbon layer covers the fiber surface, isolates oxygen and heat, and effectively inhibits flame propagation; at the same time, the phosphorus compound releases non-combustible gas during combustion, diluting the oxygen concentration and further reducing the possibility of combustion. In addition, the introduction of quaternary ammonium salt and phosphonium salt improves the thermal stability of the fiber and delays the release of volatile combustibles during thermal decomposition. The molecular structure optimization of the modified polyacrylonitrile itself increases the pyrolysis temperature, making the fiber more difficult to decompose at high temperature; in summary, the excellent flame retardant properties of the fiber are jointly constructed through the thermal insulation effect of tourmaline, the carbonization and gas dilution effect of the phosphorus material, the thermal stability contribution of the quaternary ammonium salt and phosphonium salt, and the optimized molecular and fiber structure, which are suitable for the field of high-safety textiles. DETAILED DESCRIPTION

[0046] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative work belong to the scope of protection of the present invention.

[0047] The tourmaline powder used in the present invention is purchased from Shijiazhuang Ultra-fine New Material Technology Co., Ltd., and the model is CW54281;

[0048] The calcium stearate used in the present invention is purchased from Tianjin Siyanshi Biochemical Technology Co., Ltd., and the product number is C-08652 + 500g.

[0049] Example 1

[0050] This example provides a preparation method of modified polyacrylonitrile for preparing anion-enhanced antibacterial polymer fibers, including the following steps:

[0051] Step Ⅰ. Preparation of modified tourmaline

[0052] Weigh: 70.0 g of silver nitrate and 200.0 mL of deionized water are mixed to obtain a silver nitrate solution;

[0053] Weigh: 40.0 g of tourmaline powder, 50.0 g of sodium silicate and 700.0 mL of deionized water are added to the reaction kettle and stirred. During the stirring process, 200.0 mL of silver nitrate solution is added dropwise to the reaction kettle at a constant speed, ensuring that the silver nitrate solution is added dropwise within 30 min. Then continue to stir for 30 min. After the reaction is completed, wait for the temperature of the reactant system to drop to room temperature, filter the reactant system to collect the filter cake. After washing the filter cake 3 times with absolute ethanol and deionized water, transfer the filter cake to a vacuum drying oven at 80 °C and vacuum dry to constant weight to obtain modified tourmaline.

[0054] Step Ⅱ. Preparation of antibacterial chain extender

[0055] Weigh: 50.0 g of modified tourmaline, 10.0 g of 4-aminobutyltriethoxysilane, 200.0 mL of absolute ethanol and 120.0 mL of deionized water are added to the reaction kettle and stirred. After adjusting the pH of the reaction system to 8 with saturated sodium hydroxide aqueous solution, the temperature of the reaction kettle is raised to 40 °C and kept stirring for 30 min. After the reaction is completed, wait for the temperature of the reactant system to drop to room temperature, filter the reactant system to collect the filter cake. After washing the filter cake 3 times with absolute ethanol and deionized water, transfer the filter cake to a vacuum drying oven at 80 °C and vacuum dry to constant weight to obtain the antibacterial chain extender.

[0056] Step Ⅲ. Preparation of modified polyacrylonitrile

[0057] Weigh: 40.0 g of acrylonitrile, 20.0 g of methyl acrylate and 300.0 mL of N,N-dimethylformamide are added to a reaction kettle and stirred. After the temperature of the reaction kettle rises to 60 °C, 3.0 g of azobisisobutyronitrile is added to the reaction kettle. After heat preservation and stirring for 2 h, 5.0 g of an antibacterial chain extender is added continuously, and heat preservation and stirring are carried out for 30 min. After the reaction is completed, the reaction kettle is cooled to room temperature, and the reaction solution is added to a rotary evaporator with a water bath temperature of 80 °C, and vacuum distillation is carried out until no liquid is extracted, and modified polyacrylonitrile is obtained.

[0058] Example 2

[0059] This example provides a preparation method of modified polyacrylonitrile for preparing anion-enhanced antibacterial polymer fibers, including the following steps:

[0060] Step I: Prepare modified tourmaline

[0061] Weigh: 80.0 g of silver nitrate and 300.0 mL of deionized water are mixed to obtain a silver nitrate solution;

[0062] Weigh: 50.0 g of tourmaline powder, 60.0 g of sodium silicate and 800.0 mL of deionized water are added to a reaction kettle and stirred. During the stirring process, 300.0 mL of the silver nitrate solution is added dropwise to the reaction kettle at a uniform speed, ensuring that the silver nitrate solution is added dropwise within 40 min. Continue stirring for 30 min. After the reaction is completed, wait for the temperature of the reactant system to drop to room temperature, filter the reactant system to collect the filter cake, wash the filter cake 5 times with absolute ethanol and deionized water, and then transfer the filter cake to a vacuum drying oven at 80 °C, and vacuum dry to constant weight to obtain modified tourmaline.

[0063] Step II: Prepare an antibacterial chain extender

[0064] Weigh: 60.0 g of modified tourmaline, 20.0 g of 4-aminobutyltriethoxysilane, 250.0 mL of absolute ethanol and 150.0 mL of deionized water are added to a reaction kettle and stirred. After adjusting the pH of the reaction system to 10 with a saturated sodium hydroxide aqueous solution, the temperature of the reaction kettle is raised to 50 °C, and heat preservation and stirring are carried out for 40 min. After the reaction is completed, wait for the temperature of the reactant system to drop to room temperature, filter the reactant system to collect the filter cake, wash the filter cake 5 times with absolute ethanol and deionized water, and then transfer the filter cake to a vacuum drying oven at 80 °C, and vacuum dry to constant weight to obtain an antibacterial chain extender.

[0065] Step III: Prepare modified polyacrylonitrile

[0066] Weigh: 60.0 g of acrylonitrile, 30.0 g of methyl acrylate and 360.0 mL of N,N-dimethylformamide were added to a reaction kettle and stirred. After the temperature of the reaction kettle was raised to 80 °C, 4.0 g of azobisisobutyronitrile was added to the reaction kettle. After keeping the temperature and stirring for 3 h, 8.0 g of an antibacterial chain extender was added continuously, and the temperature was kept and stirred for 40 min. After the reaction was completed, the reaction kettle was cooled to room temperature. The reaction solution was added to a rotary evaporator with a water bath temperature of 100 °C, and distilled under reduced pressure until no liquid was collected, to obtain modified polyacrylonitrile.

[0067] Example 3

[0068] This example provides a method for preparing modified polyacrylonitrile for preparing anion-enhanced antibacterial polymer fibers, including the following steps:

[0069] Step I. Prepare modified tourmaline

[0070] Weigh: 72.0 g of silver nitrate and 250.0 mL of deionized water were mixed to obtain a silver nitrate solution;

[0071] Weigh: 45.0 g of tourmaline powder, 54.0 g of sodium silicate and 720.0 mL of deionized water were added to a reaction kettle and stirred. During the stirring process, 250.0 mL of the silver nitrate solution was added dropwise to the reaction kettle at a constant speed, ensuring that the silver nitrate solution was added dropwise within 36 min. Stirring was continued for 24 min. After the reaction was completed, when the temperature of the reactant system decreased to room temperature, the reactant system was filtered by suction to collect the filter cake. After washing the filter cake 4 times with absolute ethanol and deionized water, the filter cake was transferred to a vacuum drying oven at 80 °C and vacuum dried to constant weight to obtain modified tourmaline.

[0072] Step II. Prepare an antibacterial chain extender

[0073] Weigh: 54.0 g of modified tourmaline, 16.0 g of 4-aminobutyltriethoxysilane, 240.0 mL of absolute ethanol and 120.0 mL of deionized water were added to a reaction kettle and stirred. After adjusting the pH of the reaction system to 9 with a saturated sodium hydroxide aqueous solution, the temperature of the reaction kettle was raised to 45 °C, and the temperature was kept and stirred for 36 min. After the reaction was completed, when the temperature of the reactant system decreased to room temperature, the reactant system was filtered by suction to collect the filter cake. After washing the filter cake 4 times with absolute ethanol and deionized water, the filter cake was transferred to a vacuum drying oven at 80 °C and vacuum dried to constant weight to obtain an antibacterial chain extender.

[0074] Step III. Prepare modified polyacrylonitrile

[0075] Weigh: 50.0 g of acrylonitrile, 24.0 g of methyl acrylate and 320.0 mL of N,N-dimethylformamide were added to a reaction kettle and stirred. After the temperature of the reaction kettle was raised to 70 °C, 3.6 g of azobisisobutyronitrile was added to the reaction kettle. After keeping the temperature and stirring for 3 h, 7.2 g of an antibacterial chain extender was added, and the temperature was kept and stirred for 36 min. After the reaction was completed, the reaction kettle was cooled to room temperature. The reaction solution was added to a rotary evaporator with a water bath temperature of 90 °C, and vacuum distillation was carried out until no liquid was collected, and modified polyacrylonitrile was obtained.

[0076] Example 4

[0077] This example provides a preparation method of modified acrylic fibers for preparing anion-enhanced antibacterial polymer fibers, including the following steps:

[0078] Step ①, prepare the melt

[0079] Weigh: 80.0 parts of modified polyacrylonitrile, 5.0 parts of triphenyl phosphite, 2.0 parts of calcium stearate and 5.0 parts of dibutyltin dilaurate were added to a stirring kettle. The temperature of the stirring kettle was raised to 210 °C, and it was kept warm and stirred for 10 min to obtain the melt.

[0080] Step ②, prepare the modified acrylic fiber

[0081] After the melt was filtered through a 300-mesh filter screen, a spinneret with a pore diameter of 0.15 mm and 200 holes was used for spinning. The spinning temperature was 200 °C, the extrusion speed was 1.0 g / min per hole, the side blow cooling air speed was 0.3 m / s, the air temperature was 15 °C, and the relative humidity was 40%. The initial draft ratio was 3.0 times, the draft temperature was 90 °C, and the draft speed was 200 m / min; the heat setting temperature was 130 °C, and the setting time was 0.5; the winding speed was 3600 m / min, and the tension was 0.1 cN / dtex, and the modified acrylic fiber was obtained.

[0082] Example 5

[0083] This example provides a preparation method of modified acrylic fibers for preparing anion-enhanced antibacterial polymer fibers, including the following steps:

[0084] Step ①, prepare the melt

[0085] Weigh: 100.0 parts of modified polyacrylonitrile, 8.0 parts of triphenyl phosphite, 4.0 parts of calcium stearate and 8.0 parts of dibutyltin dilaurate were added to a stirring kettle. The temperature of the stirring kettle was raised to 220 °C, and it was kept warm and stirred for 15 min to obtain the melt.

[0086] Step ②, prepare the modified acrylic fiber

[0087] After the melt is filtered through a 500-mesh filter screen, a spinneret with a pore diameter of 0.30 mm and 400 holes is used for spinning. The spinning temperature is 210 °C, the extrusion speed is 1.5 g / min per hole, the side-blowing cooling wind speed is 0.6 m / s, the wind temperature is 20 °C, and the relative humidity is 60%. The primary drawing ratio is 4.5 times, the drawing temperature is 110 °C, and the drawing speed is 300 m / min; the heat setting temperature is 150 °C, and the setting time is 0.8 s; the winding speed is 4000 m / min, and the tension is 0.2 cN / dtex, obtaining modified acrylic fibers.

[0088] Example 6

[0089] This example provides a preparation method of modified acrylic fibers for preparing anion-enhanced antibacterial polymer fibers, including the following steps:

[0090] Step ①, prepare the melt

[0091] Weigh: 90.0 parts of modified polyacrylonitrile, 6.0 parts of triphenyl phosphite, 3.0 parts of calcium stearate, and 6.0 parts of dibutyltin dilaurate and add them to a stirring kettle. The temperature of the stirring kettle is raised to 220 °C, and it is kept stirring for 12 min to obtain the melt.

[0092] Step ②, prepare modified acrylic fibers

[0093] After the melt is filtered through a 400-mesh filter screen, a spinneret with a pore diameter of 0.20 mm and 300 holes is used for spinning. The spinning temperature is 210 °C, the extrusion speed is 1.5 g / min per hole, the side-blowing cooling wind speed is 0.5 m / s, the wind temperature is 18 °C, and the relative humidity is 50%. The primary drawing ratio is 4.0 times, the drawing temperature is 100 °C, and the drawing speed is 250 m / min; the heat setting temperature is 140 °C, and the setting time is 0.5 s; the winding speed is 4000 m / min, and the tension is 0.2 cN / dtex, obtaining modified acrylic fibers.

[0094] Example 7

[0095] This example provides a preparation method of antibacterial acrylic fibers for preparing anion-enhanced antibacterial polymer fibers, including the following steps:

[0096] Step ㈠, prepare ammoniated acrylic fibers

[0097] Weigh: 40.0 g of modified acrylic fiber, 200.0 mL of 4 - allylpiperazin - 1 - amine, and 120.0 mL of deionized water were slowly added to a three - necked flask equipped with a thermometer, a stirrer, and a cooling reflux device. Under stirring conditions, the three - necked flask was heated to reflux and then kept refluxing for 5 h. After the reaction was completed, when the temperature of the reaction kettle decreased to room temperature, the fiber material was taken out. After washing the fiber material 3 times with absolute ethanol and deionized water, the fiber material was transferred to a vacuum drying oven at 80 °C and dried to a constant weight to obtain ammoniated acrylic fiber.

[0098] Step (ii), preparation of phosphated acrylic fiber

[0099] Weigh: 40.0 g of ammoniated acrylic fiber, 5.0 g of diphenylphosphine, 1.0 g of chloroplatinic acid, and 200.0 mL of absolute ethanol were added to a reaction kettle. The temperature of the reaction kettle was raised to 40 °C and kept reacting for 1 h. After the temperature of the reaction kettle decreased to room temperature, the fiber material was taken out. After washing the fiber material 3 times with absolute ethanol and deionized water, the fiber material was transferred to a vacuum drying oven at 80 °C and dried to a constant weight to obtain phosphated acrylic fiber.

[0100] Step (iii), preparation of antibacterial acrylic fiber

[0101] Weigh: 10.0 g of bromoethane and 100.0 mL of absolute ethanol were mixed to obtain a bromoethane solution;

[0102] Under the protection of nitrogen, weigh: 30.0 g of phosphated acrylic fiber and 200.0 mL of absolute ethanol were added to a reaction kettle and stirred. Then the temperature of the reaction kettle was raised to 40 °C and kept stirring for 20 min. After that, 5.0 g of triethylamine was added to the reaction system, and stirring was continued for 10 min. Then, 100.0 mL of the bromoethane solution was added dropwise to the reaction system, and the dropping continued for 1 h. Stirring was continued for 3 h. After the reaction was completed, when the temperature of the reaction kettle decreased to room temperature, the fiber material was taken out. After washing the fiber material 3 times with absolute ethanol and deionized water, the fiber material was transferred to a vacuum drying oven at 80 °C and dried to a constant weight to obtain antibacterial acrylic fiber.

[0103] Example 8

[0104] This example provides a preparation method of antibacterial acrylic fiber for preparing anion - enhanced antibacterial polymer fiber, including the following steps:

[0105] Step (i), preparation of ammoniated acrylic fiber

[0106] Weigh: 50.0 g of modified acrylic fiber, 240.0 mL of 4 - allylpiperazin - 1 - amine, and 150.0 mL of deionized water were slowly added to a three - necked flask equipped with a thermometer, a stirrer, and a cooling reflux device. Under stirring conditions, the three - necked flask was heated to reflux and then kept refluxing for 5 h. After the reaction was completed, when the temperature of the reaction kettle decreased to room temperature, the fiber material was taken out. After washing the fiber material 5 times with absolute ethanol and deionized water, the fiber material was transferred to a vacuum drying oven at 80 °C and vacuum - dried to constant weight to obtain ammoniated acrylic fiber.

[0107] Step (ii), Preparation of phosphated acrylic fiber

[0108] Weigh: 50.0 g of ammoniated acrylic fiber, 8.0 g of diphenylphosphine, 2.0 g of chloroplatinic acid, and 240.0 mL of absolute ethanol were added to a reaction kettle. The temperature of the reaction kettle was raised to 50 °C and kept reacting for 2 h. After the temperature of the reaction kettle decreased to room temperature, the fiber material was taken out. After washing the fiber material 5 times with absolute ethanol and deionized water, the fiber material was transferred to a vacuum drying oven at 80 °C and vacuum - dried to constant weight to obtain phosphated acrylic fiber.

[0109] Step (iii), Preparation of antibacterial acrylic fiber

[0110] Weigh: 20.0 g of bromoethane and 120.0 mL of absolute ethanol were mixed to obtain a bromoethane solution;

[0111] Under the protection of nitrogen, weigh: 40.0 g of phosphated acrylic fiber and 240.0 mL of absolute ethanol were added to a reaction kettle and stirred. Then the temperature of the reaction kettle was raised to 50 °C. After keeping stirring for 30 min, 8.0 g of triethylamine was added to the reactant system. After continuing to keep stirring for 120.0 min, 120.0 mL of the bromoethane solution was added dropwise to the reactant system, and the dropping continued for 2 h. Then keep stirring for 4 h. After the reaction was completed, when the temperature of the reaction kettle decreased to room temperature, the fiber material was taken out. After washing the fiber material 5 times with absolute ethanol and deionized water, the fiber material was transferred to a vacuum drying oven at 80 °C and vacuum - dried to constant weight to obtain antibacterial acrylic fiber.

[0112] Example 9

[0113] This example provides a preparation method of antibacterial acrylic fiber for preparing anion - enhanced antibacterial polymer fiber, including the following steps:

[0114] Step (i), Preparation of ammoniated acrylic fiber

[0115] Weigh: 45.0 g of modified acrylic fiber, 210.0 mL of 4 - allylpiperazin - 1 - amine, and 150.0 mL of deionized water were slowly added to a three - necked flask equipped with a thermometer, a stirrer, and a cooling reflux device. Under stirring conditions, the three - necked flask was heated to reflux and then kept refluxing for 6 h. After the reaction was completed, when the temperature of the reaction kettle decreased to room temperature, the fiber material was taken out. After washing the fiber material 4 times with absolute ethanol and deionized water, the fiber material was transferred to a vacuum drying oven at 80 °C and vacuum - dried to a constant weight to obtain ammonia - modified acrylic fiber.

[0116] Step (ii), Preparation of phosphated acrylic fiber

[0117] Weigh: 45.0 g of ammonia - modified acrylic fiber, 6.0 g of diphenylphosphine, 1.5 g of chloroplatinic acid, and 210.0 mL of absolute ethanol were added to a reaction kettle. The temperature of the reaction kettle was raised to 50 °C and kept reacting for 2 h. After the temperature of the reaction kettle decreased to room temperature, the fiber material was taken out. After washing the fiber material 4 times with absolute ethanol and deionized water, the fiber material was transferred to a vacuum drying oven at 80 °C and vacuum - dried to a constant weight to obtain phosphated acrylic fiber.

[0118] Step (iii), Preparation of antibacterial acrylic fiber

[0119] Weigh: 16.0 g of bromoethane and 120.0 mL of absolute ethanol were mixed to obtain a bromoethane solution;

[0120] Under the protection of nitrogen, weigh: 36.0 g of phosphated acrylic fiber and 210.0 mL of absolute ethanol were added to a reaction kettle and stirred. Then the temperature of the reaction kettle was raised to 45 °C and kept stirring for 24 min. After that, 7.2 g of triethylamine was added to the reaction system, and stirring was continued for 12 min. Then, 120.0 mL of the bromoethane solution was added dropwise to the reaction system, and the dropping continued for 2 h. Stirring was kept for 3 h. After the reaction was completed, when the temperature of the reaction kettle decreased to room temperature, the fiber material was taken out. After washing the fiber material 4 times with absolute ethanol and deionized water, the fiber material was transferred to a vacuum drying oven at 80 °C and vacuum - dried to a constant weight to obtain antibacterial acrylic fiber.

[0121] Comparative Example 1

[0122] The difference between this comparative example and Example 9 is that in the preparation process of the modified acrylic fiber used in step (i), in the preparation process of the modified polyacrylonitrile used in step ①, tourmaline powder was used to replace the modified antibacterial agent in equal amount.

[0123] Comparative Example 2

[0124] The difference between this comparative example and Example 9 is that step (ii) was cancelled.

[0125] Comparative Example 3

[0126] The difference between this comparative example and Example 9 is that step (iii) is cancelled.

[0127] Performance test:

[0128] Referring to the standard GB / T 30128-2013 "Detection and Evaluation of Anion Generation Quantity of Textiles", the anion concentration of the antibacterial acrylic fibers prepared in Examples 7-9 and Comparative Examples 1-3 was tested;

[0129] Referring to the standard GB / T 24253-2009 "Evaluation of Textile Anti-mite Performance", the anti-mite performance of the antibacterial acrylic fibers prepared in Examples 7-9 and Comparative Examples 1-3 was evaluated;

[0130] Referring to the standard GB / T 20944.3-2008 "Evaluation of Textile Antibacterial Properties - Part 3: Oscillation Method", the antibacterial rate of the antibacterial acrylic fibers prepared in Examples 7-9 and Comparative Examples 1-3 was detected. Among them, the selected bacterial strains were Staphylococcus aureus and Candida albicans respectively;

[0131] Referring to the standard GB / T 1040.3-2006 "Determination of Tensile Properties of Plastics - Part 3: Test Conditions for Films and Sheets", the tensile strength of the antibacterial acrylic fibers prepared in Examples 7-9 and Comparative Examples 1-3 was determined;

[0132] Referring to the standard GB / T 2408-2021 "Determination of Plastics Burning Performance - Horizontal Method and Vertical Method", the vertical burning grade of the antibacterial acrylic fibers prepared in Examples 7-9 and Comparative Examples 1-3 was tested. The specific data are shown in Table 1.

[0133] Table 1 - Performance Test Data Sheet of Each Specimen

[0134]

[0135] Data analysis:

[0136] By comparing and analyzing the data in Table 1, it can be found that the anion concentration released by the antibacterial acrylic fibers prepared in the present invention is 7458, the anti-mite ability is extremely strong, the killing rate of Staphylococcus aureus is 99.7%, the killing rate of Candida albicans is 99.6%, the tensile strength is 64.4 MPa, and the vertical burning grade is V-0 at the same time. All data are better than those of the comparative examples;

[0137] After comparative analysis of the negative ion concentrations in Table 1, it was found that the antibacterial acrylic fibers prepared in Comparative Example 1 were significantly lower than those in Example 9. This indicates that in Example 9, tourmaline was double-modified with silver silicate and silane coupling agent, enhancing the surface active sites, having a stronger interaction with water molecules in the air, generating a large number of negative ions, and maintaining long-term stable release after being embedded in the fiber matrix. In Comparative Example 1, tourmaline was used to replace the antibacterial chain extender. Although the negative ion generation ability of tourmaline was retained, the lack of synergistic effect of organic modification led to a lower negative ion release efficiency than that in Example 9.

[0138] After comparative analysis of the antibacterial and acaricidal properties in Table 1, it can be found that the antibacterial and acaricidal properties of Comparative Examples 1-3 were significantly weaker than those in Example 8. This shows that in Example 9, amino groups were introduced through an antibacterial chain extender and modified with quaternary ammonium salts and phosphonium salts to form a potent antibacterial layer. The positive charges destroy the cell structures of bacteria and mites, and silver ions and phosphorus materials further enhance the antibacterial and acaricidal effects. In Comparative Example 1, since tourmaline was used to replace the antibacterial chain extender, the negative ion release performance of the material decreased, resulting in a significant decline in antibacterial and acaricidal abilities. In Comparative Example 2, no phosphating was carried out, losing the inhibitory effect of phosphorus materials on mite metabolism, with the acaricidal performance limited and the antibacterial performance not reaching the best. In Comparative Example 3, no quaternary ammonium salinization and phosphonium salinization were carried out, lacking the core antibacterial and acaricidal mechanisms, resulting in a significant decline in antibacterial and acaricidal properties.

[0139] After comparative analysis of the tensile resistance and flame retardant properties in Table 1, it can be found that in Example 9, excellent tensile resistance was achieved through molecular optimization of modified polyacrylonitrile, the enhancing effect of tourmaline, improvement of interfacial bonding force, and optimization of the spinning process. The charring effect of phosphorus materials and the heat insulation effect of tourmaline endow it with strong flame retardancy. In Comparative Example 1, due to the lack of molecular hybridization of the antibacterial chain extender, insufficient interfacial bonding force and structural optimization, the tensile strength decreased. In Comparative Example 2, no phosphating was carried out, the tensile performance was not fully optimized, and the flame retardancy decreased significantly due to the lack of the charring effect of phosphorus compounds. In Comparative Example 3, no quaternary ammonium salinization and phosphonium salinization were carried out, the tensile performance was limited due to insufficient interfacial modification, and the flame retardancy decreased due to the lack of heat stability contribution.

[0140] Ultimately, it shows that in the present invention, after modifying the surface of tourmaline with silver silicate material, modified tourmaline was obtained, and an antibacterial chain extender was obtained by modifying amino groups on the surface of the modified tourmaline with a silane coupling agent. The antibacterial chain extender hybridized the organic chain segment structure during the process of acrylonitrile and methyl acrylate to obtain modified polyacrylonitrile. The acrylonitrile fiber was obtained by melt spinning of the modified polyacrylonitrile and auxiliary materials. After ammoniating the ester groups on the acrylonitrile fiber with 4-allylpiperazine-1-amine, a double bond structure was introduced, and phosphorus materials were introduced through hydrophosphination. Finally, through bromoethane modification, quaternary ammonium salts and phosphonium salts were introduced on the fiber surface to obtain a high-performance antibacterial acrylic fiber.

[0141] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to only the specific implementation manners. Obviously, according to the content of this specification, many modifications and changes can be made. These embodiments are selected and specifically described in this specification in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can well understand and utilize the present invention. The present invention is only limited by the claims and their full scope and equivalents.

Claims

1. A method for preparing an anion-enhanced antibacterial polymer fiber, characterized in that, It includes the following steps: S1. Add the composite polyacrylonitrile material into a stirring kettle, raise the temperature of the stirring kettle to 210 - 220 °C, keep stirring for 10 - 15 min to obtain a melt; S2. Conduct melt spinning on the melt to obtain modified acrylic fibers; S3. Conduct surface modification on the modified acrylic fibers to obtain antibacterial acrylic fibers; Among them, the composite polyacrylonitrile material comprises raw materials in the following parts by weight: 80 - 100 parts of modified polyacrylonitrile and 12 - 20 parts of auxiliary materials; The preparation method of the modified polyacrylonitrile is: Add acrylonitrile, methyl acrylate and N,N - dimethylformamide into a reaction kettle and stir. After the temperature of the reaction kettle rises to 60 - 80 °C, add azobisisobutyronitrile into the reaction kettle. After keeping stirring for 2 - 3 h, continue to add an antibacterial chain extender, keep stirring for 30 - 40 min, and conduct post - treatment to obtain modified polyacrylonitrile.

2. The preparation method of an anion-enhanced antibacterial polymer fiber according to claim 1, characterized in that, In step S1, the auxiliary materials comprise raw materials in the following parts by weight: 5 - 8 parts of antioxidant, 2 - 4 parts of lubricant and 5 - 8 parts of heat stabilizer; In the preparation process of the modified polyacrylonitrile, the dosage ratio of acrylonitrile, methyl acrylate, N,N - dimethylformamide, azobisisobutyronitrile and the antibacterial chain extender is 4 - 6 g:2 - 3 g:30 - 36 mL:0.3 - 0.4 g:0.5 - 0.8 g.

3. The preparation method of an anion-enhanced antibacterial polymer fiber according to claim 1, characterized in that, The preparation method of the antibacterial chain extender includes the following steps: A1. Add tourmaline powder, sodium silicate and deionized water into a reaction kettle and stir. During the stirring process, dropwise add silver nitrate solution into the reaction kettle at a constant speed, ensure that the silver nitrate solution is added dropwise within 30 - 40 min, continue to stir for 20 - 30 min, and conduct post - treatment to obtain modified tourmaline; A2. Add the modified tourmaline, 4 - aminobutyltriethoxysilane, absolute ethanol and deionized water into a reaction kettle and stir. After using saturated sodium hydroxide aqueous solution to adjust the pH of the reaction system to 8 - 10, raise the temperature of the reaction kettle to 40 - 50 °C, keep stirring for 30 - 40 min, and conduct post - treatment to obtain the antibacterial chain extender.

4. The preparation method of an anion-enhanced antibacterial polymer fiber according to claim 3, characterized in that, In step A1, the dosage ratio of tourmaline powder, sodium silicate, deionized water and silver nitrate solution is 4 - 5 g:5 - 6 g:70 - 80 mL:20 - 30 mL, where the silver nitrate solution is obtained by mixing 7 - 8 g of silver nitrate and 20 - 30 mL of deionized water; In step A2, the dosage ratio of the modified tourmaline, 4 - aminobutyltriethoxysilane, absolute ethanol and deionized water is 5 - 6 g:1 - 2 g:20 - 25 mL:12 - 15 mL.

5. The preparation method of an anion-enhanced antibacterial polymer fiber according to claim 1, characterized in that, In step S4, the surface modification operation includes the following steps: B1. Slowly add the modified acrylic fibers, 4 - allylpiperazin - 1 - amine and deionized water into a three - necked flask equipped with a thermometer, a stirrer and a cooling reflux device in sequence. Under the stirring condition, heat the three - necked flask to reflux, keep refluxing for 5 - 6 h, and conduct post - treatment to obtain ammoniated acrylic fibers; B2. Add the ammoniated acrylic fibers, diphenylphosphine, chloroplatinic acid and absolute ethanol into a reaction kettle, raise the temperature of the reaction kettle to 40 - 50 °C, keep reacting for 1 - 2 h to obtain phosphated acrylic fibers; B3. Under the protection of nitrogen, add phosphonitrile acrylic fiber and absolute ethanol into the reaction kettle, stir, then raise the temperature of the reaction kettle to 40 - 50 °C, keep warm and stir for 20 - 30 min, add triethylamine to the reactant system, continue to keep warm and stir for 10 - 12 min, then dropwise add bromoethane solution to the reactant system, continuously dropwise add for 1 - 2 h, keep warm and stir for 3 - 4 h, and carry out post-treatment to obtain antibacterial acrylic fiber.

6. The preparation method of an anion-enhanced antibacterial polymer fiber according to claim 5, characterized in that, In step B1, the dosage ratio of the modified acrylic fiber, 4 - allylpiperazin - 1 - amine and deionized water is 4 - 5 g : 20 - 24 mL : 12 - 15 mL; in step B2, the dosage ratio of the ammoniated acrylic fiber, diphenylphosphine, chloroplatinic acid and absolute ethanol is 4 - 5 g : 0.5 - 0.8 g : 0.1 - 0.2 g : 20 - 24 mL.

7. The preparation method of an anion-enhanced antibacterial polymer fiber according to claim 5, characterized in that In step B3, the dosage ratio of the phosphonitrile acrylic fiber, absolute ethanol, triethylamine and bromoethane solution is 3 - 4 g : 20 - 24 mL : 0.5 - 0.8 g : 10 - 12 mL, wherein the bromoethane solution is obtained by mixing bromoethane and absolute ethanol according to the dosage ratio of 1 - 2 g : 10 - 12 mL.

8. An anion-enhanced antibacterial polymer fiber, characterized in that, This anion - enhanced antibacterial polymer fiber is prepared by using the preparation method of an anion - enhanced antibacterial polymer fiber as described in any one of claims 1 - 7.

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