Preparation process of bio-based graphene quantum dot antibacterial fiber

Abstract

The invention discloses a bio-based graphene quantum dot antibacterial fiber preparation technology, and relates to the technical field of antibacterial fiber preparation. Comprising the steps of pretreatment of bio-based raw materials, preparation of a graphene quantum dot precursor, synthesis of bio-based graphene quantum dots, preparation of a spinning matrix, preparation of a spinning solution, filtration and defoaming, spinning, stretching treatment, heat setting, antibacterial after-treatment and the like. According to the process, bio-based graphene quantum dots are prepared through pretreatment and hydrothermal reaction of bio-based raw materials, so that the dispersity of the bio-based graphene quantum dots and the compatibility of the bio-based graphene quantum dots and a spinning matrix are improved; parameters of all links are accurately controlled, and stable fiber quality is ensured. The prepared antibacterial fiber has excellent antibacterial performance and mechanical performance, is lasting in antibacterial effect, good in biocompatibility and environment-friendly, adopts mature equipment, is convenient for industrial production, and has wide application prospects in the fields of medical treatment and public health, clothing textile and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of antibacterial fiber preparation, in particular to a preparation process of antibacterial fiber based on graphene quantum dots. BACKGROUND

[0002] Antibacterial fiber is a kind of fiber material with special function, which has a wide range of applications in the fields of medical and health, food packaging, household supplies, etc. With the continuous improvement of people's health and hygiene requirements, the market demand for antibacterial fiber is increasing.

[0003] In the prior art, there are various methods for preparing antibacterial fiber. Among them, physical blending method is a commonly used method, which is to mix antibacterial agent with spinning raw material and then spin. For example, silver-based antibacterial agent, zinc oxide and other inorganic antibacterial agents are blended with polyester, polyamide and other polymers, and antibacterial fiber is prepared by melt spinning. This method is relatively simple to operate and easy to realize industrialized production, but has some obvious shortcomings. First, the dispersion of inorganic antibacterial agent in polymer matrix is poor, which is easy to cause aggregation, resulting in uneven antibacterial performance of the fiber and affecting the use effect. Secondly, the compatibility of inorganic antibacterial agent and polymer is poor, which will reduce the mechanical properties of the fiber such as breaking strength and elongation at break. In addition, some inorganic antibacterial agents have certain toxicity, which may cause environmental pollution after the use and disposal of the fiber.

[0004] Chemical grafting method is also a method for preparing antibacterial fiber, which is to graft antibacterial groups to the surface or interior of the fiber through chemical reaction. For example, antibacterial monomers are grafted to the surface of cotton fiber by using ultraviolet irradiation, so that the fiber has antibacterial performance. Chemical grafting method can improve the bonding force between antibacterial agent and fiber and prolong the antibacterial time, but the process of this method is relatively complex, the reaction conditions are harsh, and the reaction temperature, time, monomer concentration and other parameters need to be accurately controlled, which results in high production cost. At the same time, some organic solvents and initiators may be used in the process of chemical grafting, and the volatilization of these substances will harm the health of the operators and also have negative impact on the environment.

[0005] In addition, some natural antibacterial agents such as chitosan and plant extracts are also applied in the preparation of antibacterial fiber. Natural antibacterial agents have the advantages of good biocompatibility and low toxicity, but the antibacterial effect of natural antibacterial agents is relatively weak, and they are easy to be damaged by high temperature and high pressure conditions in the spinning process, resulting in the decrease of antibacterial performance. At the same time, the stability of natural antibacterial agents is poor, which is easy to decompose during the storage and use of the fiber, affecting the durability of antibacterial performance.

[0006] In the application of graphene quantum dots, the existing technology has studied its use in antibacterial materials, but the process of combining bio-based raw materials with graphene quantum dots to prepare antibacterial fibers is not mature enough. In the current preparation process, the preparation of graphene quantum dots mostly uses chemical oxidation method, which requires the use of strong acid, strong alkali and other corrosive reagents, not only requiring high equipment, but also producing a large amount of wastewater and waste gas, polluting the environment. At the same time, the composite method of graphene quantum dots and bio-based raw materials is relatively simple, and the composite effect is not good, resulting in the performance of the antibacterial fiber not being ideal. In addition, the existing process does not control the parameters in the spinning process accurately, affecting the quality of the fiber and the stability of the antibacterial performance. SUMMARY

[0007] In view of the deficiencies of the prior art, the present application provides a bio-based graphene quantum dot antibacterial fiber preparation process, which solves the problems raised in the above background art.

[0008] To achieve the above purpose, the present application realizes the following technical scheme: a bio-based graphene quantum dot antibacterial fiber preparation process, comprising the following steps: Step one: put the straw cellulose and chitosan into a high-speed mixer at a mass fraction of 80%-90%:10%-20%, mix at a speed of 700-900r / min and a temperature of 55-65℃ for 25-35min, and obtain a mixed bio-based raw material; then crush it to a particle size of 40-60μm for standby; Step two: mix citric acid and urea at a mass ratio of 2-4:1, add deionized water to make the solid-liquid ratio 1:4-6, stir until completely dissolved, and obtain a precursor solution; Step three: put the pretreated mixed bio-based raw material and the precursor solution into a hydrothermal reaction kettle at a mass ratio of 1:3-5, react at a temperature of 170-190℃ and a pressure of 1.8-2.2MPa for 5-7h; after reaction, cool to room temperature, centrifuge to take the supernatant, and dialyze to obtain a bio-based graphene quantum dot solution with a concentration of 1.2-1.8mg / mL; Step four: dry the polylactic acid particles, add them to a twin-screw extruder for melt extrusion, and obtain polylactic acid melt as a spinning matrix; Step five: put the bio-based graphene quantum dot solution and the polylactic acid melt into a static mixer at a volume ratio of 1:7-9, mix at a temperature of 160-180℃ and a pressure of 0.4-0.6MPa for 35-45min, and obtain a spinning solution with a viscosity of 700-900mPa・s; Step six: filter the spinning solution, put it into a debubbling tank at a temperature of 150-170℃ and a vacuum degree of-0.07 to-0.09MPa for 25-35min; Step seven: the defoaming spinning solution is sent into a melt spinning machine, and under the conditions of a spinning temperature of 170-190℃, a spinning speed of 900-1100m / min, and a spinneret hole diameter of 0.15-0.25mm, a nascent fiber is obtained; Step eight: the nascent fiber is introduced into a drawing machine for two-stage drawing, and the total drawing multiple is 2.5-3.5 times; Step nine: the drawn fiber is placed into a heat setting machine for heat setting under the conditions of a temperature of 90-110℃ and a tension of 4-6cN for 20-40s; Step ten: the heat set fiber is treated by padding with an antibacterial solution and then dried to obtain a bio-based graphene quantum dot antibacterial fiber.

[0009] Optionally, the degree of deacetylation of the chitosan in step one is 85%-90%.

[0010] Optionally, the purity of both the citric acid and the urea in step two is 99%, and the stirring speed is 400-600r / min.

[0011] Optionally, the rotation speed of the hydrothermal reaction kettle in step three is 7000-9000r / min, and the centrifugation time is 15-25min; the dialysis bag has a molecular weight cut-off of 800-1200Da, and the dialysis is performed in deionized water for 60-84h, with the deionized water being replaced every 6-10h; the dialysis bag is made of regenerated cellulose, and the volume of the deionized water is 40-60 times that of the product.

[0012] Optionally, the polylactic acid particles in step four have a molecular weight of 70000-90000, a density of 1.23-1.25g / cm³, and a melt index of 9-11g / 10min (190℃, 2.16kg); the particles are dried in a vacuum drying oven under the conditions of a temperature of 75-85℃ and a vacuum degree of -0.08 to -0.1MPa for 10-14h. The rotation speed of the screw is 140-160r / min, and the temperatures of the zones are 150-165℃, 160-175℃, 170-190℃, and 165-180℃.

[0013] Optionally, the number of mixing elements in step five is 8-12, and the length of each element is 40-60mm; and an online viscometer is used to monitor the viscosity.

[0014] Optionally, the plate and frame filter is used to filter the spinning solution in step six, and the filter screen has a hole diameter of 4-6μm.

[0015] Optionally, the cooling air temperature of the melt spinning machine in step seven is 20-30℃, the air speed is 0.4-0.6m / s, and the fiber winding tension is 8-12cN.

[0016] Optionally, the first-stage stretching temperature in step eight is 55-65 DEG C, the stretching multiple is 1.8-2.2 times; the second-stage stretching temperature is 75-85 DEG C, the stretching multiple is 1.3-1.7 times; the drawing speed is 45-55 m / min, and the stretching roller surface temperature fluctuation range is ±1-3 DEG C.

[0017] Optionally, the antibacterial solution in step ten is a chitosan quaternary ammonium salt solution with a mass fraction of 1.5-2.5%, a molecular weight of 40,000-110,000, and a pH value of 6.0-7.5; the treatment is carried out under the conditions of a padding pressure of 0.2-0.4 MPa and a pick-up rate of 75-85%; and then the fabric is placed in an oven and dried at a temperature of 75-85 DEG C for 15-25 min.

[0018] The application provides a preparation process of antibacterial fiber of bio-based graphene quantum dots. The preparation process of antibacterial fiber of bio-based graphene quantum dots mixes straw cellulose and chitosan at a specific ratio and grinds them to a suitable particle size, laying a foundation for uniform compounding of the bio-based graphene quantum dots.

[0019] In the synthesis process of the bio-based graphene quantum dots, a hydrothermal reaction method is used to make the bio-based raw materials and graphene quantum dot precursors fully react, forming bio-based graphene quantum dots with stable structures and improving the dispersibility of the bio-based graphene quantum dots in the spinning solution.

[0020] In the entire preparation process, the raw materials used are mostly bio-based materials such as straw cellulose and chitosan, which are widely available and low in price, thereby reducing production costs.

[0021] The graphene quantum dots have good antibacterial activity, and after being compounded with the bio-based raw material, the antibacterial effect is greatly enhanced. Meanwhile, the bio-based graphene quantum dots have high stability and are not easily damaged under high temperature and high pressure conditions in the spinning process. Through the close combination with the spinning matrix, the bio-based graphene quantum dots are not easily decomposed and lost in the storage and use of the fiber, and the durability of the antibacterial performance is ensured. DETAILED DESCRIPTION

[0022] The technical solutions in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are only some of the embodiments of the present application, but not all.

[0023] The preparation process of the antibacterial fiber of the bio-based graphene quantum dots comprises the following steps: Step one: put the straw cellulose and chitosan in a high-speed mixer at a mass ratio of 80%-90%:10%-20%, mix at a speed of 700-900 r / min and a temperature of 55-65 DEG C for 25-35 min, and obtain mixed bio-based raw material, the deacetylation degree of chitosan is 85%-90%, and then crush it to a particle size of 40-60 microns for standby; Step two: mix citric acid and urea at a mass ratio of 2-4:1, add deionized water to make the solid-liquid ratio 1:4-6, stir until completely dissolved, and obtain a precursor solution, wherein the purity of citric acid and urea is 99%, and the stirring speed is 400-600 r / min; Step three: put the pretreated mixed bio-based raw material and the precursor solution into a hydrothermal reaction kettle at a mass ratio of 1:3-5, react at a temperature of 170-190 DEG C and a pressure of 1.8-2.2 MPa for 5-7 h; after reaction, cool to room temperature, centrifuge to obtain supernatant, and dialysis to obtain a bio-based graphene quantum dot solution with a concentration of 1.2-1.8 mg / mL; The rotation speed of the hydrothermal reaction kettle is 7000-9000 r / min, the centrifugation time is 15-25 min; the dialysis bag has a molecular weight cut-off of 800-1200 Da, and is dialyzed in deionized water for 60-84 h, the deionized water is replaced every 6-10 h, the dialysis bag is made of regenerated cellulose, and the volume of deionized water is 40-60 times that of the product; Step four: dry the polylactic acid particles, add them into a twin-screw extruder for melt extrusion, obtain polylactic acid melt as a spinning matrix, the molecular weight of the polylactic acid particles is 70000-90000, the density is 1.23-1.25 g / cm3, and the melt index is 9-11 g / 10 min (190 DEG C, 2.16 kg); use a vacuum drying oven to dry at a temperature of 75-85 DEG C and a vacuum degree of-0.08 to-0.1 MPa for 10-14 h; Wherein, the screw rotation speed is 140-160 r / min, and the temperature of each zone is 150-165℃, 160-175℃, 170-190℃ and 165-180℃ respectively. Step five: the bio-based graphene quantum dot solution and polylactic acid melt are put into a static mixer at a volume ratio of 1:7-9, mixed at a temperature of 160-180℃ and a pressure of 0.4-0.6 MPa for 35-45 min to obtain a spinning solution, the viscosity of which is controlled at 700-900 mPa·s, the number of mixing elements is 8-12, and the length of each element is 40-60 mm; and an online viscometer is used to monitor the viscosity; Step six: after the spinning solution is filtered, it is put into a debubbling tank and debubbled at a temperature of 150-170℃ and a vacuum degree of -0.07 to -0.09 MPa for 25-35 min; the spinning solution is filtered by using a plate and frame filter, and the filter screen aperture is 4-6 μm; Step seven: the debubbled spinning solution is sent into a melt spinning machine to obtain a nascent fiber under the conditions of a spinning temperature of 170-190℃, a spinning speed of 900-1100 m / min and a spinneret aperture of 0.15-0.25 mm; the cooling air temperature of the melt spinning machine is 20-30℃, the air speed is 0.4-0.6 m / s, and the fiber winding tension is 8-12 cN; Step eight: the nascent fiber is introduced into a drawing machine for two-stage stretching, the total draw ratio is 2.5-3.5, the first-stage stretching temperature is 55-65℃, the draw ratio is 1.8-2.2, the second-stage stretching temperature is 75-85℃, the draw ratio is 1.3-1.7, the pulling speed is 45-55 m / min, and the surface temperature fluctuation range of the drawing roller is ±1-3℃; Step nine: the stretched fiber is put into a heat setting machine and heat set at a temperature of 90-110℃ and a tension of 4-6 cN for 20-40 s; Step ten: the heat set fiber is treated by immersion in an antibacterial solution and then dried to obtain a bio-based graphene quantum dot antibacterial fiber; the antibacterial solution is a chitosan quaternary ammonium salt solution with a mass fraction of 1.5-2.5%, a molecular weight of 40000-110000 and a pH value of 6.0-7.5; the treatment is carried out under the conditions of an immersion pressure of 0.2-0.4 MPa and a pick-up rate of 75-85%; and then the fiber is put into an oven and dried at a temperature of 75-85℃ for 15-25 min.

[0024] Example 1: a bio-based graphene quantum dot antibacterial fiber is prepared according to the above process, and the specific parameters are as follows: In step one, the mass fraction of straw cellulose is 85%, and the mass fraction of chitosan is 15%; the high-speed mixer is operated at a rotation speed of 800 r / min, a temperature of 60℃ and for 30 min; and the pulverizer is used to crush the mixture to a particle size of 50 μm. The mass ratio of citric acid to urea in step two is 3:1, the solid-liquid ratio is 1:5, and the rotating speed of the magnetic stirrer is 500 r / min. In step three, the mass ratio of the mixed bio-based raw material to the precursor solution is 1:4, the temperature of the hydrothermal reactor is 180℃, the pressure is 2 MPa, the reaction time is 6 h, the rotating speed of the centrifuge is 8000 r / min, the centrifugation time is 20 min, the molecular weight cut-off of the dialysis bag is 1000 Da, the dialysis time is 72 h, and the concentration of the bio-based graphene quantum dot solution is 1.5 mg / mL. In step four, the drying temperature of the polylactic acid particles is 80℃, the vacuum degree is-0.09 MPa, and the drying time is 12 h; the rotating speed of the screw of the twin-screw extruder is 150 r / min, and the temperature of each zone is 160℃, 170℃, 180℃, and 175℃. In step five, the volume ratio of the bio-based graphene quantum dot solution to the polylactic acid melt is 1:8, the temperature of the static mixer is 170℃, the pressure is 0.5 MPa, and the mixing time is 40 min; the viscosity of the spinning solution is 800 mPa・s. In step six, the pore size of the filter screen of the plate-and-frame filter is 5 μm, the temperature of the defoaming tank is 160℃, the vacuum degree is-0.08 MPa, and the defoaming time is 30 min. In step seven, the spinning temperature of the melt spinning machine is 180℃, the spinning speed is 1000 m / min, the pore size of the spinneret is 0.2 mm, the cooling air temperature is 25℃, the air speed is 0.5 m / s, and the winding tension is 10 cN. In step eight, the first-stage stretching temperature is 60℃, the stretching multiple is 2 times, the second-stage stretching temperature is 80℃, the stretching multiple is 1.5 times, the pulling speed is 50 m / min, and the surface temperature fluctuation of the stretching roller is ±2℃. In step nine, the temperature of the heat setting machine is 100℃, the tension is 5 cN, and the heat setting time is 30 s. In step ten, the mass fraction of the chitosan quaternary ammonium salt is 2%, the molecular weight is 50-100 thousand, and the pH value is 6.5-7.0; the pressure of the padding machine is 0.3 MPa, the rolling rate is 80%, the oven temperature is 80℃, and the drying time is 20 min.

[0025] Example 2, compared with Example 1, only the temperature of the hydrothermal reaction in step three is changed to 200℃, the pressure is 2.5 MPa, and other parameters remain unchanged, to prepare the bio-based graphene quantum dot antibacterial fiber.

[0026] Example 3, compared with Example 1, only the spinning speed of the melt spinning machine in step seven is changed to 1200 m / min, and other parameters remain unchanged, to prepare the bio-based graphene quantum dot antibacterial fiber.

[0027] Comparative Example 1 Using the existing physical blending method, zinc oxide antibacterial agent and polylactic acid are mixed in a mass ratio of 5:95 to prepare antibacterial fibers by melt spinning, with a spinning temperature of 180℃ and a spinning speed of 1000 m / min.

[0028] Comparative Example 2 The antibacterial monomer was grafted with the cotton fiber under ultraviolet irradiation by using the existing chemical grafting method, the reaction temperature was 60℃, and the reaction time was 2h, to prepare the antibacterial fiber.

[0029] Performance comparison table of examples and comparative examples

[0030] Conclusion: The preparation process of the bio-based graphene quantum dot antibacterial fiber (Examples 1-3) provided by the application is significantly better than the prior art (Comparative Examples 1-2) in comprehensive performance.

[0031] The antibacterial effect of Examples 1-3 on Escherichia coli and Staphylococcus aureus is better than that of Comparative Example 1, and the antibacterial performance stability is higher, and there is no antibacterial rate fluctuation problem caused by antibacterial agent aggregation in Comparative Example 1; compared with Comparative Example 2, the long-term antibacterial effect of Examples is more advantageous, and the antibacterial rate retention rate is significantly higher after 50 times of washing, which reflects more durable antibacterial performance. The breaking strength and elongation at break of Examples 1-3 are higher than those of Comparative Examples 1 and 2, which shows that the present process effectively solves the problem of mechanical property decline caused by poor compatibility of antibacterial agent and matrix in the prior art by optimizing the pretreatment of bio-based raw materials, spinning parameters and stretching process, so that the fiber has excellent antibacterial property and mechanical strength at the same time. In terms of environmental protection and safety, Examples 1-3 use bio-based raw materials throughout the process, and there is no wastewater and waste gas emission in the production process, and the biocompatibility is excellent, which avoids the toxicity risk of inorganic antibacterial agent in Comparative Example 1 and the environmental hazards of organic solvent volatilization in Comparative Example 2, and meets the requirements of green and sustainable development; In summary, the present application successfully overcomes the defects of uneven antibacterial performance, poor mechanical property, insufficient environmental protection and complex process in the existing antibacterial fiber preparation technology through the synergistic design of bio-based raw materials and graphene quantum dots, precise parameter control in multiple steps and optimization of environmentally friendly process route, and the prepared antibacterial fiber has high application value in the fields of medical health, clothing and textiles.

[0032] The above is only the preferred specific implementation method of the present application, but the protection scope of the present application is not limited to this, any skilled person in the technical field according to the technical solution and the inventive concept of the present application within the technical range disclosed by the present application makes equivalent replacement or change, which should be covered in the protection scope of the present application.

Claims

1. A process for preparing antibacterial fibers containing bio-based graphene quantum dots, characterized in that: The following steps are involved: Step 1: Place straw cellulose and chitosan in a high-speed mixer at a mass ratio of 80%-90%:10%-20%, and mix them at a speed of 700-900 r / min and a temperature of 55-65°C for 25-35 minutes to obtain a mixed bio-based raw material; then crush it to a particle size of 40-60 μm for later use; Step 2: Mix citric acid and urea in a mass ratio of 2-4:1, add deionized water to make a solid-liquid ratio of 1:4-6, and stir until completely dissolved to obtain a precursor solution; Step 3: Place the pretreated mixed bio-based raw materials and the precursor solution in a hydrothermal reactor at a mass ratio of 1:3-5, and react at a temperature of 170-190°C and a pressure of 1.8-2.2 MPa for 5-7 hours; after the reaction, cool to room temperature, centrifuge, and obtain the supernatant, which is dialyzed to obtain a bio-based graphene quantum dot solution with a concentration of 1.2-1.8 mg / mL; Step 4: After the polylactic acid particles are dried, they are added to a twin-screw extruder for melt extrusion to obtain a polylactic acid melt as a spinning matrix; Step 5: Place the bio-based graphene quantum dot solution and the polylactic acid melt in a static mixer at a volume ratio of 1:7-9, and mix them at a temperature of 160-180°C and a pressure of 0.4-0.6 MPa for 35-45 minutes to obtain a spinning solution with a viscosity of 700-900 mPa·s; Step 6: After filtering the spinning solution, place it in a degassing tank and degas for 25-35 minutes at a temperature of 150-170°C and a vacuum degree of -0.07 to -0.09 MPa; Step 7: The deaerated spinning solution is fed into a melt spinning machine to obtain nascent fibers at a spinning temperature of 170-190°C, a spinning speed of 900-1100 m / min, and a spinneret aperture of 0.15-0.25 mm. Step 8: Introduce the spun fiber into a stretching machine for two-stage stretching, with a total stretching ratio of 2.5-3.5 times; Step 9: Place the stretched fiber into a heat setting machine and heat set it for 20-40 seconds at a temperature of 90-110°C and a tension of 4-6 cN. Step 10: The heat-set fiber is subjected to padding treatment with an antibacterial solution and then dried to obtain a bio-based graphene quantum dot antibacterial fiber.

2. The process for preparing antibacterial fiber containing bio-based graphene quantum dots according to claim 1, characterized in that: In the step 1, the degree of deacetylation of chitosan is 85%-90%.

3. The process for preparing antibacterial fiber containing bio-based graphene quantum dots according to claim 1, characterized in that: In the step 2, the purity of citric acid and urea is 99%, and the stirring speed is 400-600 r / min.

4. The process for preparing antibacterial fiber containing bio-based graphene quantum dots according to claim 1, characterized in that: In step 3, the speed of the hydrothermal reactor is 7000-9000 r / min, and the centrifugation time is 15-25 min; the dialysis bag has a molecular weight cutoff of 800-1200 Da, and the dialysis is carried out in deionized water for 60-84 h, with the deionized water being replaced every 6-10 h. The dialysis bag is made of regenerated cellulose, and the volume of deionized water is 40-60 times the volume of the product.

5. The process for preparing antibacterial fiber containing bio-based graphene quantum dots according to claim 1, characterized in that: The polylactic acid particles in step 4 have a molecular weight of 70,000-90,000, a density of 1.23-1.25 g / cm³, and a melt index of 9-11 g / 10 min (190°C, 2.16 kg); and are dried in a vacuum drying oven at a temperature of 75-85°C and a vacuum degree of -0.08 to -0.1 MPa for 10-14 hours; Among them, the screw speed is 140-160r / min, and the temperature of each zone is 150-165℃, 160-175℃, 170-190℃, and 165-180℃.

6. The process for preparing antibacterial fiber containing bio-based graphene quantum dots according to claim 1, characterized in that: In step 5, the number of mixing elements is 8-12, and the length of each element is 40-60 mm; The viscosity was monitored using an online viscometer.

7. The process for preparing antibacterial fiber containing bio-based graphene quantum dots according to claim 1, characterized in that: In step 6, the spinning solution is filtered using a plate and frame filter with a filter mesh size of 4-6 μm.

8. The process for preparing antibacterial fiber containing bio-based graphene quantum dots according to claim 1, characterized in that: In the step 7, the cooling air temperature of the melt spinning machine is 20-30° C., the wind speed is 0.4-0.6 m / s, and the fiber winding tension is 8-12 cN.

9. The process for preparing antibacterial fiber containing bio-based graphene quantum dots according to claim 1, characterized in that: In step eight, the first-stage stretching temperature is 55-65°C, and the stretching ratio is 1.8-2.2 times; the second-stage stretching temperature is 75-85°C, and the stretching ratio is 1.3-1.7 times; the traction speed is 45-55m / min, and the surface temperature fluctuation range of the stretching roller is ±1-3°C.

10. The process for preparing antibacterial fiber containing bio-based graphene quantum dots according to claim 1, characterized in that: The antibacterial solution in step 10 is a chitosan quaternary ammonium salt solution with a mass fraction of 1.5-2.5%, a molecular weight of 40,000-110,000, and a pH value of 6.0-7.5; the solution is treated under a padding pressure of 0.2-0.4 MPa and a padding rate of 75-85%; and then placed in an oven and dried at a temperature of 75-85° C. for 15-25 minutes.

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