Plant-based antibacterial fiber and preparation method thereof
Plant-based antibacterial fibers were prepared by mixing modified microcrystalline cellulose and polypropylene and treating with thiophene, which solved the problems of insufficient flame retardancy, antibacterial properties and aging resistance of plant-based fibers, and achieved excellent comprehensive performance.
Patent Information
- Application Number
- CN202511856993.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-10
- Publication Date
- 2026-02-06
AI Technical Summary
Plant-based fibers are deficient in terms of flame retardancy, antibacterial properties, and aging resistance, and are especially prone to mold growth in humid environments, which can affect health.
Plant-based antibacterial fibers were prepared by blending modified microcrystalline cellulose with modified polypropylene, melt spinning, and surface treatment with thiophene. The modification process included introducing hindered phenolic structures and trifluoromethyl groups onto the microcrystalline cellulose, introducing phosphorus and quaternary phosphonium salts onto the polypropylene, and using thiophene for surface finishing.
It achieves excellent flame retardant, antibacterial, waterproof and antistatic properties of plant-based fibers, improves the aging resistance of fibers, and is suitable for a variety of application environments.
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Abstract
Description
TECHNICAL FIELD
[0001] The application relates to the field of fibers, in particular to a plant-based antibacterial fiber and a preparation method thereof. BACKGROUND
[0002] The plant-based fiber is a fiber material extracted or processed from natural plants, has the characteristics of being renewable, degradable and environment-friendly, and is widely applied to the fields of textiles, medical treatment, packaging, aerospace and the like. The biodegradable material taking the plant fiber as the raw material has the advantages of being environment-friendly and renewable, and has become an important choice for replacing traditional materials.
[0003] The plant-based fiber indeed has obvious deficiencies in the aspect of flame retardancy, which is mainly related to the natural organic components and the chemical structure characteristics, and the porous structure of the plant fiber is easy to absorb moisture and sebum, and provides a breeding environment for bacteria and fungi. Especially in a humid environment, the plant fiber product is prone to mildew, releases mold spores, and causes harm to human health. Therefore, the application introduces a plant-based antibacterial fiber and a preparation method thereof. SUMMARY
[0004] The application aims to provide a plant-based antibacterial fiber and a preparation method thereof to solve the problems in the prior art.
[0005] A plant-based antibacterial fiber is prepared by mixing modified polypropylene and modified microcrystalline cellulose, melt spinning, and finally performing surface treatment with thiophene. The modified microcrystalline cellulose is prepared by sequentially reacting microcrystalline cellulose with 2-bromo-1-[3,5-di(tert-butyl)-4-hydroxyphenyl]ethanone and 3,5-di(trifluoromethyl)aniline. The modified polypropylene is prepared by sequentially reacting polypropylene with allyldiphenylphosphine and 3-chloromethylthiophene.
[0006] A preparation method of a plant-based antibacterial fiber mainly comprises the following preparation steps: (1) mixing pre-modified microcrystalline cellulose, 3,5-di(trifluoromethyl)aniline, Å-type molecular sieve and toluene according to a mass ratio of 4-6:1:2-3:20-30, stirring at 200-300 r / min and 158-162 DEG C for 23.5-24.5 h, cooling to room temperature, filtering, removing the molecular sieve, washing with methanol for 4-6 times, and vacuum drying at-10-0 DEG C for 23-25 h to prepare modified microcrystalline cellulose; (2) Mix pre-modified polypropylene, acetone and sodium iodide at a mass ratio of 4~6:48~52:0.6~0.8, stir at 38~42℃, 200~300r / min under nitrogen protection for 8~12min, add 0.18~0.22 times the mass of pre-modified polypropylene and stir for 5~7h, filter, wash with deionized water 4~6 times, and vacuum dry at -10~0℃ for 24~26h to obtain modified polypropylene; (3) Thiophene and chloroform are mixed evenly at a mass ratio of 1:11~13 to prepare a thiophene solution; the composite fiber is immersed in the thiophene solution and left to stand for 45~55s at 35~45℃ under nitrogen protection. After being taken out, it is vacuum dried at 35~45℃ for 24~26h, washed with ethanol 3~5 times, and vacuum dried at -10~0℃ for 22~26h to obtain plant-based fiber.
[0007] As an optimization, the pre-modified microcrystalline cellulose in step (1) is prepared by mixing 2-bromo-1-[3,5-di(tert-butyl)-4-hydroxyphenyl] ethyl ketone, microcrystalline cellulose, and isopropanol in a mass ratio of 1:3~5:26~30, stirring at 58~62℃ and 200~300r / min for 12~13h, vacuum drying at -10~0℃ for 46~50h, washing with methanol 4~6 times, and vacuum drying at -10~0℃ for 23~25h.
[0008] As an optimization, the pre-modified polypropylene in step (1) is prepared by heating polypropylene with a degree of polymerization of 2000 to 180~182℃, stirring at 55~65r / min for 4~6min, adding allyl diphenylphosphine at 0.12~0.14 times the mass of polypropylene, stirring at 180~182℃ for 6~8min, adding dicumyl peroxide at 0.003~0.004 times the mass of polypropylene, stirring for 10~12min, cooling to room temperature, pulverizing to a particle size of 2~3mm, washing with deionized water 4~6 times, and vacuum drying at -10~0℃ for 24~26h.
[0009] As an optimization, the composite fiber in step (3) is prepared by mixing modified polypropylene and modified microcrystalline cellulose at a mass ratio of 1:1, heating to 166~170℃, stirring at 40~60r / min for 8~12min, melt spinning, placing the spun filaments into a parallel drawing machine with a drawing ratio of 1.9~2.1, letting it stand at 90~100℃ for 20~30s, and naturally cooling to room temperature.
[0010] As an optimization, the specific operation of melt spinning is as follows: spinning temperature 178~182℃, extrusion rate 19~21r / min, and winding rate 9~11r / min.
[0011] As an optimization, the thiophene solution in step (3) is prepared by mixing thiophene and chloroform in a mass ratio of 1:11~13.
[0012] Compared with the prior art, the beneficial effects achieved by the present invention are: In preparing plant-based antibacterial fibers, the present invention involves reacting microcrystalline cellulose sequentially with 2-bromo-1-[3,5-di(tert-butyl)-4-hydroxyphenyl]ethyl ketone and 3,5-di(trifluoromethyl)aniline to obtain modified microcrystalline cellulose; reacting polypropylene sequentially with allyl diphenylphosphine and 3-chloromethylthiophene to obtain modified polypropylene; mixing the modified polypropylene and modified microcrystalline cellulose, melt spinning, and finally surface treating with thiophene to obtain plant-based antibacterial fibers.
[0013] First, microcrystalline cellulose was reacted sequentially with 2-bromo-1-[3,5-di(tert-butyl)-4-hydroxyphenyl]ethyl ketone and 3,5-di(trifluoromethyl)aniline to prepare modified microcrystalline cellulose. Then, the microcrystalline cellulose was reacted with 2-bromo-1-[3,5-di(tert-butyl)-4-hydroxyphenyl]ethyl ketone to introduce a hindered phenolic structure onto the cellulose surface. The hindered phenolic structure contains large-volume tert-butyl substituents at the ortho position of the phenolic hydroxyl group, forming a steric hindrance effect that prevents direct contact between the phenolic hydroxyl group and metal ions or oxidants, while also maintaining molecular stability. This gives the microcrystalline cellulose excellent aging resistance. Further reaction with 3,5-di(trifluoromethyl)aniline introduces a trifluoromethyl group. The trifluoromethyl group, with its extremely low surface energy, can significantly reduce the contact angle between the material surface and water, thus giving the fiber excellent waterproofing capabilities.
[0014] Secondly, modified polypropylene was prepared by reacting polypropylene sequentially with allyl diphenylphosphine and 3-chloromethylthiophene. The polypropylene was then reacted with allyl diphenylphosphine to introduce phosphorus, followed by reaction with 3-chloromethylthiophene to generate a quaternary phosphonium salt. This salt absorbs a large amount of heat during thermal decomposition, releasing non-flammable gases such as hydrogen bromide, forming a heat-insulating layer to prevent flame spread, and exhibiting excellent flame-retardant properties. Simultaneously, the positively charged quaternary phosphonium salt adsorbs onto the negatively charged bacterial cell membrane surface through electrostatic interactions, disrupting the membrane structure and causing leakage of cell contents. It also inhibits the activity of key enzymes such as bacterial dehydrogenases and oxidases, interfering with energy metabolism and substance synthesis, thereby achieving an antibacterial effect. Finally, modified polypropylene and modified microcrystalline cellulose were mixed, melt-spun, and then surface-treated with thiophene to obtain plant-based antibacterial fibers. Thiophene finishing was then applied to form a layer of polythiophene on the surface. Polythiophene, as a conductive polymer, can improve the antistatic properties of the fibers. Detailed Implementation
[0015] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention. Example 1:
[0016] A method for preparing plant-based antibacterial fibers mainly includes the following preparation steps: (1) 2-bromo-1-[3,5-di(tert-butyl)-4-hydroxyphenyl] ethyl ketone, microcrystalline cellulose, and isopropanol were mixed in a mass ratio of 1:3:26, stirred at 58℃ and 200 r / min for 12 h, dried under vacuum at -10℃ for 46 h, washed with methanol 4 times, and dried under vacuum at -10℃ for 23 h to obtain pre-modified microcrystalline cellulose; pre-modified microcrystalline cellulose, 3,5-di(trifluoromethyl)aniline, Å-type molecular sieve, and toluene were mixed in a mass ratio of 4:1:2:20, stirred at 200 r / min and 158℃ for 23.5 h, cooled to room temperature, filtered, molecular sieve removed, washed with methanol 4 times, and dried under vacuum at -10℃ for 23 h to obtain modified microcrystalline cellulose; (2) Polypropylene with a degree of polymerization of 2000 was heated to 180°C and stirred at 55 r / min for 4 min. Then, allyl diphenylphosphine with a mass of 0.12 times that of polypropylene was added and stirred at 180°C for 6 min. Dicumyl peroxide with a mass of 0.003 times that of polypropylene was added and stirred for 10 min. The mixture was cooled to room temperature, pulverized to a particle size of 2 mm, washed 4 times with deionized water, and vacuum dried at -10°C for 24 h to obtain pre-modified polypropylene. Pre-modified polypropylene, acetone and sodium iodide were mixed at a mass ratio of 4:48:0.6 and stirred at 38°C, 200 r / min and nitrogen protection for 8 min. 3-chloromethylthiophene with a mass of 0.18 times that of pre-modified polypropylene was added at a uniform rate at 8 min. The mixture was stirred for 5 h, filtered, washed 4 times with deionized water, and vacuum dried at -10°C for 24 h to obtain modified polypropylene. (3) Modified polypropylene and modified microcrystalline cellulose were mixed at a mass ratio of 1:1, heated to 166℃, stirred at 40r / min for 8min, melt spun at a spinning temperature of 178℃, extrusion rate of 19r / min, and winding rate of 9r / min. The spun filaments were placed in a parallel drawing machine with a drawing ratio of 1.9, and allowed to stand at 90℃ for 20s. The filaments were then allowed to cool naturally to room temperature to obtain composite fibers. Thiophene and chloroform were mixed evenly at a mass ratio of 1:11 to obtain a thiophene solution. The composite fibers were immersed in the thiophene solution and allowed to stand at 35℃ under nitrogen protection for 45s. The fibers were then removed, vacuum dried at 35℃ for 24h, washed three times with ethanol, and vacuum dried at -10℃ for 22h to obtain plant-based fibers. Implementation: 2:
[0017] A method for preparing plant-based antibacterial fibers mainly includes the following preparation steps: (1) 2-bromo-1-[3,5-di(tert-butyl)-4-hydroxyphenyl] ethyl ketone, microcrystalline cellulose, and isopropanol were mixed in a mass ratio of 1:4:28, stirred at 60℃ and 250 r / min for 12.5 h, dried under vacuum at -5℃ for 48 h, washed with methanol 5 times, and dried under vacuum at -5℃ for 24 h to obtain pre-modified microcrystalline cellulose; pre-modified microcrystalline cellulose, 3,5-di(trifluoromethyl)aniline, Å-type molecular sieve, and toluene were mixed in a mass ratio of 5:1:2.5:25, stirred at 250 r / min and 160℃ for 24 h, cooled to room temperature, filtered, molecular sieve removed, washed with methanol 5 times, and dried under vacuum at -5℃ for 24 h to obtain modified microcrystalline cellulose; (2) Polypropylene with a degree of polymerization of 2000 was heated to 181°C and stirred at 60 r / min for 5 min. Then, allyl diphenylphosphine with a mass of 0.13 times that of polypropylene was added and stirred at 181°C for 7 min. Then, dicumyl peroxide with a mass of 0.0035 times that of polypropylene was added and stirred for 11 min. The mixture was cooled to room temperature, pulverized to a particle size of 2.5 mm, washed with deionized water 5 times, and vacuum dried at -5°C for 25 h to obtain pre-modified polypropylene. Pre-modified polypropylene, acetone and sodium iodide were mixed at a mass ratio of 5:50:0.7 and stirred at 40°C, 250 r / min and nitrogen protection for 10 min. 3-chloromethylthiophene with a mass of 0.2 times that of pre-modified polypropylene was added at a uniform rate at 9 min. The mixture was stirred for 6 h, filtered, washed with deionized water 5 times, and vacuum dried at -5°C for 25 h to obtain modified polypropylene. (3) Modified polypropylene and modified microcrystalline cellulose are mixed at a mass ratio of 1:1, heated to 168°C, stirred at 50 r / min for 10 min, melt spun at a spinning temperature of 180°C, extrusion rate of 20 r / min, and winding rate of 10 r / min. The spun yarn is placed in a parallel drawing machine with a drawing ratio of 2, and left to stand at 95°C for 25 s. It is then naturally cooled to room temperature to obtain composite fiber. Thiophene and chloroform are mixed evenly at a mass ratio of 1:12 to obtain thiophene solution. The composite fiber is immersed in the thiophene solution, left to stand at 40°C under nitrogen protection for 50 s, removed, and vacuum dried at 40°C for 25 h. It is then washed 4 times with ethanol and vacuum dried at -5°C for 24 h to obtain plant-based fiber. Implementation: 3:
[0018] A method for preparing plant-based antibacterial fibers mainly includes the following preparation steps: (1) 2-bromo-1-[3,5-di(tert-butyl)-4-hydroxyphenyl] ethyl ketone, microcrystalline cellulose, and isopropanol were mixed in a mass ratio of 1:5:30, stirred at 62℃ and 300 r / min for 13 h, dried under vacuum at 0℃ for 50 h, washed with methanol 6 times, and dried under vacuum at 0℃ for 25 h to obtain pre-modified microcrystalline cellulose; pre-modified microcrystalline cellulose, 3,5-di(trifluoromethyl)aniline, Å-type molecular sieve, and toluene were mixed in a mass ratio of 6:1:3:30, stirred at 300 r / min and 162℃ for 24.5 h, cooled to room temperature, filtered, molecular sieve removed, washed with methanol 6 times, and dried under vacuum at 0℃ for 25 h to obtain modified microcrystalline cellulose; (2) Polypropylene with a degree of polymerization of 2000 was heated to 182°C and stirred at 65 r / min for 6 min. Then, allyl diphenylphosphine with a mass of 0.14 times that of polypropylene was added and stirred at 182°C for 8 min. Dicumyl peroxide with a mass of 0.004 times that of polypropylene was added and stirred for 12 min. The mixture was cooled to room temperature, pulverized to a particle size of 3 mm, washed with deionized water 6 times, and vacuum dried at 0°C for 26 h to obtain pre-modified polypropylene. Pre-modified polypropylene, acetone and sodium iodide were mixed at a mass ratio of 6:52:0.8 and stirred at 42°C, 300 r / min and nitrogen protection for 12 min. 3-chloromethylthiophene with a mass of 0.22 times that of pre-modified polypropylene was added at a uniform rate at 10 min and stirred for 7 h. The mixture was filtered, washed with deionized water 6 times, and vacuum dried at 0°C for 26 h to obtain modified polypropylene. (3) Modified polypropylene and modified microcrystalline cellulose were mixed at a mass ratio of 1:1, heated to 170°C, stirred at 60 r / min for 12 min, melt spun at a spinning temperature of 182°C, extrusion rate of 21 r / min, and winding rate of 11 r / min. The spun filaments were placed in a parallel drawing machine with a drawing ratio of 2.1, and allowed to stand at 100°C for 30 s. The filaments were then allowed to cool naturally to room temperature to obtain composite fibers. Thiophene and chloroform were mixed evenly at a mass ratio of 1:13 to obtain a thiophene solution. The composite fibers were immersed in the thiophene solution and allowed to stand at 45°C under nitrogen protection for 55 s. The fibers were then removed, vacuum dried at 45°C for 26 h, washed with ethanol 5 times, and vacuum dried at 0°C for 26 h to obtain plant-based fibers.
[0019] Comparative Example 1: The difference between the preparation method of the plant-based antibacterial fiber in Comparative Example 1 and that in Example 2 lies in step (1). Step (1) is modified as follows: 2-bromo-1-[3,5-di(tert-butyl)-4-hydroxyphenyl] ethyl ketone, microcrystalline cellulose, and isopropanol are mixed in a mass ratio of 1:4:28, stirred at 60°C and 250 r / min for 12.5 h, vacuum dried at -5°C for 48 h, washed five times with methanol, and vacuum dried at -5°C for 24 h to obtain modified microcrystalline cellulose. The remaining steps are the same as in Example 2.
[0020] Comparative Example 2: The preparation method of the plant-based antibacterial fiber in Comparative Example 2 differs from that in Example 2 in that the microcrystalline cellulose is not modified. The remaining steps are the same as in Example 2.
[0021] Comparative Example 3: The difference between the preparation method of the plant-based antibacterial fiber in Comparative Example 3 and that in Example 2 lies in step (3). Step (3) is modified as follows: Modified polypropylene and modified microcrystalline cellulose are mixed at a mass ratio of 1:1, heated to 168°C, stirred at 50 r / min for 10 min, melt-spun at a spinning temperature of 180°C, an extrusion rate of 20 r / min, and a winding rate of 10 r / min. The spun filament is placed in a parallel drawing machine with a drawing ratio of 2, allowed to stand at 95°C for 25 s, and then naturally cooled to room temperature to obtain the plant-based fiber. The remaining steps are the same as in Example 2.
[0022] Comparative Example 4: The difference between the preparation method of the plant-based antibacterial fiber in Comparative Example 3 and that in Comparative Example 3 lies in step (2). Step (2) is modified as follows: The difference between the preparation method of the plant-based antibacterial fiber in Comparative Example 3 and that in Example 2 lies in step (3). Step (3) is modified as follows: Polypropylene with a degree of polymerization of 2000 is heated to 181°C and stirred at 60 r / min for 5 min. Then, 0.13 times the mass of polypropylene is added to allyl diphenylphosphine, and stirring is continued at 181°C for 7 min. Then, 0.0035 times the mass of polypropylene is added to dicumyl peroxide, and stirring is continued for 11 min. The mixture is cooled to room temperature, pulverized to a particle size of 2.5 mm, washed 5 times with deionized water, and vacuum dried at -5°C for 25 h to obtain modified polypropylene. The remaining steps are the same as in Comparative Example 3.
[0023] Comparative Example 5: The preparation method of the plant-based antibacterial fiber in Comparative Example 3 differs from that in Comparative Example 3 in that it does not modify polypropylene. The remaining steps are the same as in Comparative Example 3.
[0024] Test Example 1: Antistatic, waterproof and flame retardant tests: Antistatic testing method: Test the surface resistivity of the material; Flame retardant test method: The limiting oxygen index is tested according to GB / T5454 test standard; Waterproofing test: The surface water contact angle of the test material was measured. The results are shown in Table 1.
[0025] Table 1
[0026] A comparison of the experimental data in Table 1 shows that the plant-based antibacterial fiber prepared by this invention has good antistatic, flame-retardant and waterproof properties.
[0027] A comparison of the experimental data of Examples 1, 2, 3 and Comparative Example 1 in Table 1 reveals that Examples 1, 2, and 3 have larger water contact angles. The difference between Comparative Example 1 and the Examples is that trifluoromethyl groups were not introduced. This indicates that trifluoromethyl groups, with their extremely low surface energy, can significantly reduce the contact angle between the material surface and water, thereby giving the fiber excellent waterproofing capabilities. A comparison of the experimental data from Examples 1, 2, 3 and Comparative Example 3 reveals that Examples 1, 2, and 3 have low surface resistivity. The difference between Comparative Example 3 and the Examples is that thiophene was not used for post-treatment, indicating that a layer of polythiophene is generated on the surface. As a conductive polymer, polythiophene can improve the antistatic ability of the fiber.
[0028] A comparison of the experimental data from Examples 1, 2, 3 and Comparative Example 5 reveals that Examples 1, 2, and 3 have a high limiting oxygen index. The difference between Comparative Example 5 and the Examples is that phosphorus was not introduced, indicating that it can absorb a large amount of heat during thermal decomposition and release non-flammable gases such as hydrogen bromide, forming a heat insulation layer to prevent the spread of flames, thus exhibiting excellent flame retardant capabilities.
[0029] Test Example 2: Antibacterial test: Test method: The test was conducted according to GB / T20944.3, with Escherichia coli and Staphylococcus aureus selected as the bacterial strains. The results are shown in Table 2.
[0030] Table 2
[0031] A comparison of the experimental data in Table 2 shows that the plant-based antibacterial fiber prepared by this invention has good antibacterial ability.
[0032] A comparison of the experimental data from Examples 1, 2, 3 and Comparative Example 4 in Table 2 reveals that Examples 1, 2, and 3 exhibit high antibacterial rates. The difference between Comparative Example 4 and the Examples lies in the absence of quaternary phosphonium salts. This indicates that quaternary phosphonium salts carry a positive charge and adsorb onto the negatively charged bacterial cell membrane surface through electrostatic interactions, thereby disrupting the membrane structure and causing leakage of cell contents. Furthermore, they can inhibit the activity of key enzymes such as bacterial dehydrogenases and oxidases, interfering with energy metabolism and substance synthesis, thus achieving an antibacterial effect.
[0033] Test Example 3: Aging resistance test: Aging resistance test method: The fibers prepared in each example and comparative example were tested. The tensile strength was tested according to GB / T9997 and recorded as A0. The samples were irradiated with a fluorescent ultraviolet lamp UV-A340 for 15 days, and the tensile strength was tested again and recorded as A1. The tensile strength retention rate was calculated, where the tensile strength retention rate = A1 / A0 × 100%. The results are shown in Table 3.
[0034] Table 3
[0035] A comparison of the experimental data in Table 3 shows that the plant-based antibacterial fiber prepared by this invention has good aging resistance.
[0036] A comparison of the experimental data of Examples 1, 2, 3 and Comparative Example 2 in Table 3 reveals that Examples 1, 2, and 3 exhibit high fracture strength retention rates. The difference between Comparative Example 2 and the Examples is that hindered phenol was not introduced. This indicates that a large-volume tert-butyl group or other substituent exists at the ortho position of the phenolic hydroxyl group in the hindered phenol structure, forming a steric hindrance effect that prevents the phenolic hydroxyl group from directly contacting metal ions or oxidants. At the same time, it maintains molecular stability, resulting in excellent aging resistance of the fiber.
[0037] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., 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 plant-based antibacterial fiber, characterized in that, The plant-based antibacterial fiber is prepared by mixing modified polypropylene and modified microcrystalline cellulose, melt spinning, and finally surface treatment with thiophene. The modified microcrystalline cellulose is prepared by reacting microcrystalline cellulose sequentially with 2-bromo-1-[3,5-di(tert-butyl)-4-hydroxyphenyl] ethyl ketone and 3,5-di(trifluoromethyl)aniline. The modified polypropylene is prepared by reacting polypropylene sequentially with allyl diphenylphosphine and 3-chloromethylthiophene.
2. A method for preparing plant-based antibacterial fibers, characterized in that, The preparation method of the plant-based antibacterial fiber mainly includes the following preparation steps: (1) Premodified microcrystalline cellulose, 3,5-di(trifluoromethyl)aniline, Å-type molecular sieve and toluene are mixed in a mass ratio of 4~6:1:2~3:20~30, stirred at 200~300r / min and 158~162℃ for 23.5~24.5h, cooled to room temperature, filtered, molecular sieve removed, washed with methanol 4~6 times, and vacuum dried at -10~0℃ for 23~25h to obtain modified microcrystalline cellulose; (2) Mix pre-modified polypropylene, acetone and sodium iodide at a mass ratio of 4~6:48~52:0.6~0.8, stir at 38~42℃, 200~300r / min under nitrogen protection for 8~12min, add 0.18~0.22 times the mass of pre-modified polypropylene and stir for 5~7h, filter, wash with deionized water 4~6 times, and vacuum dry at -10~0℃ for 24~26h to obtain modified polypropylene; (3) Thiophene and chloroform are mixed evenly at a mass ratio of 1:11~13 to prepare a thiophene solution; the composite fiber is immersed in the thiophene solution and left to stand for 45~55s at 35~45℃ under nitrogen protection. After being taken out, it is vacuum dried at 35~45℃ for 24~26h, washed with ethanol 3~5 times, and vacuum dried at -10~0℃ for 22~26h to obtain plant-based fiber.
3. The method for preparing a plant-based antibacterial fiber according to claim 2, characterized in that, The pre-modified microcrystalline cellulose in step (1) is prepared by mixing 2-bromo-1-[3,5-di(tert-butyl)-4-hydroxyphenyl] ethyl ketone, microcrystalline cellulose, and isopropanol in a mass ratio of 1:3~5:26~30, stirring at 58~62℃ and 200~300r / min for 12~13h, vacuum drying at -10~0℃ for 46~50h, washing with methanol 4~6 times, and vacuum drying at -10~0℃ for 23~25h.
4. The method for preparing a plant-based antibacterial fiber according to claim 2, characterized in that, The pre-modified polypropylene in step (1) is prepared by heating polypropylene with a degree of polymerization of 2000 to 180~182℃, stirring at 55~65r / min for 4~6min, adding allyl diphenylphosphine at 0.12~0.14 times the mass of polypropylene, stirring at 180~182℃ for 6~8min, adding dicumyl peroxide at 0.003~0.004 times the mass of polypropylene, stirring for 10~12min, cooling to room temperature, pulverizing to a particle size of 2~3mm, washing with deionized water 4~6 times, and vacuum drying at -10~0℃ for 24~26h.
5. The method for preparing a plant-based antibacterial fiber according to claim 2, characterized in that, The composite fiber described in step (3) is prepared by mixing modified polypropylene and modified microcrystalline cellulose at a mass ratio of 1:1, heating to 166~170℃, stirring at 40~60r / min for 8~12min, melt spinning, placing the spun filaments into a parallel drawing machine with a drawing ratio of 1.9~2.1, letting it stand at 90~100℃ for 20~30s, and then naturally cooling to room temperature.
6. The method for preparing a plant-based antibacterial fiber according to claim 5, characterized in that, The specific operation of melt spinning is as follows: spinning temperature 178~182℃, extrusion rate 19~21r / min, and winding rate 9~11r / min.
7. The method for preparing a plant-based antibacterial fiber according to claim 2, characterized in that, The thiophene solution in step (3) is prepared by mixing thiophene and chloroform in a mass ratio of 1:11~13.