Antibacterial and bacteriostatic polyamide fiber and preparation method thereof

Abstract

The invention relates to an antibacterial polyamide fiber and a preparation method thereof, and belongs to the technical field of fiber preparation, and the preparation method specifically comprises the following steps: firstly, carrying out acid oxidation treatment on a multi-walled carbon nanotube to increase oxygen-containing functional groups such as carboxyl on the surface of the multi-walled carbon nanotube and improve the dispersity of the multi-walled carbon nanotube in an aqueous solution; then, a surfactant is used for further modifying the multi-walled carbon nanotubes subjected to acid oxidation treatment, the compatibility between the multi-walled carbon nanotubes and polyamide master batches is enhanced, and therefore uniform distribution of the multi-walled carbon nanotubes in the polyamide fibers is achieved. And mixing the dopamine modified carbon nanotubes, metal salt ions, a flexibilizer and polyamide master batches to prepare the polyamide fiber with excellent antibacterial and bacteriostatic properties. According to the method, not only are the dispersity and compatibility of the multi-walled carbon nanotubes in the polyamide fiber improved, but also chelation of metal ions is realized through metal-ion coordination bonds and an adsorption effect, and the antibacterial effect of the polyamide fiber is further enhanced.

Description

Technical Field

[0001] The present application relates to the technical field of fiber preparation, and more specifically, to an antibacterial and antimicrobial polyamide fiber and a preparation method thereof. Background Art

[0002] With the advancement of science and technology and the improvement of people's living standards, the functional requirements for fiber materials are getting higher and higher. Especially in the fields of medical care, hygiene, textiles, etc., antibacterial and antimicrobial properties have become one of the important indicators to measure the quality of fiber materials. As an important type of synthetic fiber, polyamide fiber is widely used due to its excellent mechanical properties and wear resistance. However, traditional polyamide fibers have deficiencies in antibacterial and antimicrobial properties and are difficult to meet the needs of specific fields. In order to improve the antibacterial and antimicrobial properties of polyamide fibers, researchers have conducted a lot of exploration. Among them, multi-walled carbon nanotubes are considered to be a potential antibacterial material due to their unique nanostructure and excellent physical and chemical properties. However, multi-walled carbon nanotubes have poor dispersibility and compatibility in the polymer matrix and are easy to agglomerate, which limits their antibacterial effect in polyamide fibers.

[0003] Based on the above statements, the present application provides an antibacterial and antimicrobial polyamide fiber and a preparation method thereof. Summary of the invention

[0004] In order to solve the problems raised in the background technology, the present application provides an antibacterial and antibacterial polyamide fiber and a preparation method thereof. First, multi-walled carbon nanotubes are subjected to acid oxidation treatment to increase oxygen-containing functional groups such as carboxyl groups on their surfaces and improve their dispersibility in aqueous solution. Subsequently, a surfactant is used to further modify the multi-walled carbon nanotubes after acid oxidation treatment to enhance their compatibility with polyamide masterbatch, thereby achieving uniform distribution of the multi-walled carbon nanotubes in the polyamide fiber. Subsequently, dopamine-modified carbon nanotubes, metal salt ions, toughening agents and polyamide masterbatch are mixed to prepare polyamide fibers with excellent antibacterial and antibacterial properties. This method not only improves the dispersibility and compatibility of multi-walled carbon nanotubes in polyamide fibers, but also realizes the chelation of metal ions through metal-ion coordination bonds and adsorption, further enhancing the antibacterial effect of polyamide fibers. The preparation method of the present invention is simple, easy to operate, and suitable for industrial production. The prepared antibacterial and antibacterial polyamide fiber maintains the excellent properties of traditional polyamide fibers, and has good antibacterial and antibacterial effects, and is suitable for a variety of textile applications.

[0005] The present application provides an antibacterial and antimicrobial polyamide fiber and a preparation method thereof, which adopts the following technical scheme:

[0006] A method for preparing antibacterial and antimicrobial polyamide fiber comprises the following preparation steps:

[0007] S1, subjecting multi-walled carbon nanotubes to acid oxidation treatment, and then sequentially modifying them using a surfactant and dopamine hydrochloride to prepare dopamine-modified carbon nanotubes;

[0008] S2. The dopamine-modified carbon nanotubes, metal salt ions, toughening agent and polyamide masterbatch obtained in step S1 are mixed, and then the system temperature is increased to 280-290° C. and maintained for 10-15 minutes, and then the obtained melt is melt-spinned to obtain an antibacterial and antimicrobial polyamide fiber.

[0009] Furthermore, in step S1, the dopamine-modified carbon nanotubes are prepared by the following steps:

[0010] S11, adding the multi-walled carbon nanotube raw material to the mixed acid solution, ultrasonically dispersing, then raising the system temperature to 60-80° C., treating for 2-3 hours, cooling to room temperature, filtering, washing the filtered product, and obtaining acid-oxidized multi-walled carbon nanotubes;

[0011] S12. Mix the acid-oxidized multi-walled carbon nanotubes obtained in step S11 with a surfactant, disperse the system in deionized water, perform ultrasonic treatment, then wash, resuspend in deionized water, add EDC, NHS and dopamine hydrochloride, and stir for 20-30 hours at room temperature in an inert gas atmosphere to obtain dopamine-modified carbon nanotubes.

[0012] Furthermore, in step S1, the dopamine-modified carbon nanotubes are prepared by the following steps:

[0013] S11, adding a multi-walled carbon nanotube raw material to a mixed acid solution at a mass volume ratio of 1 g: (8-12) mL, ultrasonically dispersing for 30-40 minutes, then raising the system temperature to 60-80° C., treating for 2-3 hours, cooling to room temperature, filtering, and washing the filtered product with deionized water until the pH value of the washing solution is neutral, to obtain acid-oxidized multi-walled carbon nanotubes;

[0014] S12. The acid-oxidized multi-walled carbon nanotubes obtained in step S11 are mixed with a surfactant in a mass ratio of 1:(0.8-1.5), and the system is dispersed in deionized water in a mass volume ratio of 1 g:10 mL, and ultrasonically treated for 1-3 hours, followed by washing with deionized water, and resuspended in deionized water in a mass volume ratio of 1 g:10 mL, and EDC, NHS and dopamine hydrochloride are added, and stirred at a rate of 30-90 rpm for 20-30 hours at room temperature and in an inert gas atmosphere to obtain dopamine-modified carbon nanotubes.

[0015] In the above reaction process, a composite acid solution is used to perform acid oxidation treatment on multi-walled carbon nanotubes to increase the content of oxygen-containing functional groups such as carboxyl groups on the surface of multi-walled carbon nanotubes; then a surfactant is used to modify the acid-oxidized multi-walled carbon nanotubes, and the interactions such as adsorption inclusion and hydrogen bonds of carbon nanotubes are used to obtain surfactant-modified multi-walled carbon nanotubes. Then, under the EDC / NHS system, the amino groups on the dopamine molecules are used to react with the modified multi-walled carbon nanotubes to generate amide covalent bonds, thereby preparing dopamine-modified carbon nanotubes.

[0016] Preferably, in step S11, the mixed acid solution is composed of concentrated sulfuric acid and concentrated nitric acid; wherein the volume ratio of concentrated sulfuric acid to concentrated nitric acid is 3:1.

[0017] Preferably, in step S12, the frequency of ultrasonic treatment is 20-25KHz and the power is 300-500W.

[0018] Preferably, in step S12, the mass ratio of acidified multi-walled carbon nanotubes, EDC, NHS and dopamine hydrochloride is (1-6):(0.1-0.3):(0.05-0.2):(0.2-1).

[0019] Furthermore, in step S12, the surfactant is obtained by mixing sodium dodecylbenzene sulfonate, sodium octyl sulfonate and octyltrimethylammonium chloride in a mass ratio of 1:1:(0.1-1).

[0020] Furthermore, in step S2, the mass ratio of dopamine-modified carbon nanotubes, metal salt ions, toughening agent and polyamide masterbatch is (0.5-5):(0.1-1):(1-5):100.

[0021] Furthermore, the metal salt ion is at least one of copper chloride, copper sulfate, silver nitrate, zinc sulfate, magnesium sulfate and zinc chloride.

[0022] Furthermore, the toughening agent is at least one of a nanoparticle toughening agent, a polyolefin toughening agent, a rubber elastomer toughening agent, and a core-shell copolymer toughening agent.

[0023] In summary, this application has the following beneficial effects:

[0024] (1) In the technical solution of the present invention, the carboxyl and other oxygen-containing functional groups on the surface of the multi-walled carbon nanotubes are increased by acid oxidation treatment, thereby improving their dispersibility in aqueous solution; subsequently, a surfactant is used for further modification, thereby enhancing the compatibility between the carbon nanotubes and the polyamide masterbatch, and facilitating the uniform distribution of the carbon nanotubes in the polyamide fiber. The amino groups of dopamine are used to react with the modified multi-walled carbon nanotubes to generate amide covalent bonds, thereby preparing dopamine-modified carbon nanotubes. This makes it have excellent dispersibility and compatibility, and also gives the polyamide fiber good antibacterial and antimicrobial properties.

[0025] In the modification process of multi-walled carbon nanotubes, after the multi-walled carbon nanotubes are acidified, strong interactions occur between the molecules and the stacking becomes more compact. Surfactants are used to modify the multi-walled carbon nanotubes after acid oxidation treatment to improve their dispersibility in the system and promote the subsequent modification effect of dopamine hydrochloride.

[0026] (2) In the technical solution of the present invention, sodium dodecylbenzene sulfonate (SDBS), sodium octyl sulfonate (SDS) and octyl trimethyl ammonium chloride (CTAC) are used to prepare a surfactant system. The composite system can improve the dispersibility of multi-walled carbon nanotubes and promote the subsequent amidation reaction. The benzene ring structure of SDBS and the sp 2 Hybridized C=C bonds form π-π conjugation, which helps to disperse nanotubes; SDS, as a polar sulfonate, can disperse nanotubes in polar water. The compounded surfactant can more effectively coat the nanotubes and prevent them from reaggregating. The two are more likely to form a mixed micelle system after compounding with CTAC, which increases the density of active sites on the surface of multi-walled carbon nanotubes, thereby promoting the amidation reaction, making the obtained dopamine-modified carbon nanotubes have a better adsorption effect on metal salt ions.

[0027] (3) In the technical solution of the present invention, dopamine-modified carbon nanotubes, metal salt ions, toughening agents and polyamide masterbatches are mixed to prepare antibacterial and antimicrobial polyamide fibers. The catechol functional groups on the dopamine-modified carbon nanotubes can chelate metal ions with metal salt ions through metal-ion coordination bonds and the adsorption of multi-walled carbon nanotubes, thereby improving the antibacterial effect of metal salt ions on polyamide fibers. After modification, multi-walled carbon nanotubes and polyamide also contain amide bond functional groups, which makes the multi-walled carbon nanotubes more compatible with the matrix, and the prepared polyamide fibers have better mechanical properties.

[0028] At the same time, dopamine-modified carbon nanotubes (i.e., dopamine-modified multi-walled carbon nanotubes) contain catechol functional groups, which can make them adaptable to more types of toughening agents in the polyamide matrix, and promote the dispersion effect of each component in the system through hydrophobic interaction and π-π stacking with toughening agents containing alkane chains and benzene rings, thereby further improving the reinforcing effect of the toughening agent on polyamide fibers. DETAILED DESCRIPTION

[0029] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] The specific implementation methods of this application involve:

[0031] Polyamide masterbatch: amine value: 200-240 mgKOH / g, viscosity (40°C): 15000-35000 mPa.s.

[0032] Dopamine hydrochloride: CAS No. 62-31-7, provided by Shanghai Dibai Chemical Technology Co., Ltd., product No. K100381, purity 98%.

[0033] Example 1

[0034] The present application provides an antibacterial and antimicrobial polyamide fiber and a preparation method thereof, which adopts the following technical scheme:

[0035] A method for preparing antibacterial and antimicrobial polyamide fiber, specifically comprising the following preparation steps:

[0036] S1. A multi-walled carbon nanotube is subjected to acid oxidation treatment, and then modified with a surfactant and dopamine hydrochloride in sequence to prepare dopamine-modified carbon nanotubes. The specific steps are as follows:

[0037] S11, adding a multi-walled carbon nanotube raw material to a mixed acid solution at a mass volume ratio of 1 g: 8 mL, ultrasonically dispersing for 30 minutes, then raising the system temperature to 60° C., treating for 2 hours, cooling to room temperature, filtering, and washing the filtered product with deionized water until the pH value of the washing solution is neutral, to obtain acid-oxidized multi-walled carbon nanotubes;

[0038] The mixed acid solution is composed of concentrated sulfuric acid and concentrated nitric acid; wherein the volume ratio of concentrated sulfuric acid to concentrated nitric acid is 3:1;

[0039] S12, mixing the acid-oxidized multi-walled carbon nanotubes obtained in step S11 with a surfactant at a mass ratio of 1:0.8, dispersing the system in deionized water at a mass volume ratio of 1 g:10 mL, ultrasonically treating for 1 hour, then washing with deionized water, resuspending in deionized water at a mass volume ratio of 1 g:10 mL, adding EDC, NHS and dopamine hydrochloride, stirring at a rate of 30 rpm for 20 hours at room temperature and a nitrogen atmosphere, to obtain dopamine-modified carbon nanotubes;

[0040] The frequency of ultrasonic treatment is 20KHz and the power is 300W; the mass ratio of acidified multi-walled carbon nanotubes, EDC, NHS and dopamine hydrochloride is 1:0.1:0.05:0.2; and the surfactant is obtained by mixing sodium dodecylbenzene sulfonate, sodium octyl sulfonate and octyltrimethylammonium chloride in a mass ratio of 1:1:0.1.

[0041] S2, mixing the dopamine-modified carbon nanotubes, metal salt ions, toughening agent and polyamide masterbatch obtained in step S1, then raising the system temperature to 280° C. and maintaining for 10 minutes, and then melt-spinning the obtained melt, with a spinneret diameter of 0.3 mm and a winding speed of 20 rpm, to obtain an antibacterial and antimicrobial polyamide fiber;

[0042] The mass ratio of dopamine-modified carbon nanotubes, metal salt ions, toughening agent and polyamide masterbatch is 0.5:0.1:1:100; the metal salt ions are cupric chloride; and the toughening agent is butadiene rubber with an average Mw of 200,000-300,000.

[0043] Example 2

[0044] The present application provides an antibacterial and antimicrobial polyamide fiber and a preparation method thereof, which adopts the following technical scheme:

[0045] A method for preparing antibacterial and antimicrobial polyamide fiber, specifically comprising the following preparation steps:

[0046] S1. A multi-walled carbon nanotube is subjected to acid oxidation treatment, and then modified with a surfactant and dopamine hydrochloride in sequence to prepare dopamine-modified carbon nanotubes. The specific steps are as follows:

[0047] S11, adding a multi-walled carbon nanotube raw material to a mixed acid solution at a mass volume ratio of 1 g: 10 mL, ultrasonically dispersing for 30 minutes, then raising the system temperature to 70° C., treating for 2.5 hours, cooling to room temperature, filtering, and washing the filtered product with deionized water until the pH value of the washing solution is neutral, to obtain acid-oxidized multi-walled carbon nanotubes;

[0048] The mixed acid solution is composed of concentrated sulfuric acid and concentrated nitric acid; wherein the volume ratio of concentrated sulfuric acid to concentrated nitric acid is 3:1;

[0049] S12, mixing the acid-oxidized multi-walled carbon nanotubes obtained in step S11 with a surfactant at a mass ratio of 1:1.2, dispersing the system in deionized water at a mass volume ratio of 1 g:10 mL, ultrasonically treating for 2 hours, then washing with deionized water, resuspending in deionized water at a mass volume ratio of 1 g:10 mL, adding EDC, NHS and dopamine hydrochloride, stirring at room temperature and nitrogen atmosphere at a rate of 60 rpm for 25 hours, to obtain dopamine-modified carbon nanotubes;

[0050] The frequency of ultrasonic treatment is 22KHz and the power is 400W; the mass ratio of acidified multi-walled carbon nanotubes, EDC, NHS and dopamine hydrochloride is 4:0.2:0.1:0.6; and the surfactant is obtained by mixing sodium dodecylbenzene sulfonate, sodium octyl sulfonate and octyltrimethylammonium chloride in a mass ratio of 1:1:0.5.

[0051] S2, mixing the dopamine-modified carbon nanotubes, metal salt ions, toughening agent and polyamide masterbatch obtained in step S1, then raising the system temperature to 285° C. and maintaining for 12 minutes, and then melt-spinning the obtained melt, with a spinneret diameter of 0.3 mm and a winding speed of 20 rpm, to obtain an antibacterial and antimicrobial polyamide fiber;

[0052] The mass ratio of dopamine-modified carbon nanotubes, metal salt ions, toughening agent and polyamide masterbatch is 3:0.5:3:100; the metal salt ions are zinc sulfate; and the toughening agent is nano-calcium carbonate with a particle size of 20 nm.

[0053] Example 3

[0054] The present application provides an antibacterial and antimicrobial polyamide fiber and a preparation method thereof, which adopts the following technical scheme:

[0055] A method for preparing antibacterial and antimicrobial polyamide fiber, specifically comprising the following preparation steps:

[0056] S1. A multi-walled carbon nanotube is subjected to acid oxidation treatment, and then modified with a surfactant and dopamine hydrochloride in sequence to prepare dopamine-modified carbon nanotubes. The specific steps are as follows:

[0057] S11, adding a multi-walled carbon nanotube raw material to a mixed acid solution at a mass volume ratio of 1 g:12 mL, ultrasonically dispersing for 40 minutes, then raising the system temperature to 80° C., treating for 3 hours, cooling to room temperature, filtering, and washing the filtered product with deionized water until the pH value of the washing solution is neutral, to obtain acid-oxidized multi-walled carbon nanotubes;

[0058] The mixed acid solution is composed of concentrated sulfuric acid and concentrated nitric acid; wherein the volume ratio of concentrated sulfuric acid to concentrated nitric acid is 3:1;

[0059] S12, the acid-oxidized multi-walled carbon nanotubes obtained in step S11 were mixed with a surfactant at a mass ratio of 1:1.5, the system was dispersed in deionized water at a mass volume ratio of 1 g:10 mL, ultrasonically treated for 3 hours, then washed with deionized water, resuspended in deionized water at a mass volume ratio of 1 g:10 mL, EDC, NHS and dopamine hydrochloride were added, and stirred at room temperature and nitrogen atmosphere at a rate of 90 rpm for 30 hours to obtain dopamine-modified carbon nanotubes;

[0060] The frequency of ultrasonic treatment is 25KHz and the power is 500W; the mass ratio of acidified multi-walled carbon nanotubes, EDC, NHS and dopamine hydrochloride is 6:0.3:0.2:1; and the surfactant is obtained by mixing sodium dodecylbenzene sulfonate, sodium octyl sulfonate and octyltrimethylammonium chloride in a mass ratio of 1:1:1.

[0061] S2, mixing the dopamine-modified carbon nanotubes, metal salt ions, toughening agent and polyamide masterbatch obtained in step S1, then raising the system temperature to 290° C. and maintaining for 15 minutes, and then melt-spinning the obtained melt, with a spinneret diameter of 0.3 mm and a winding speed of 20 rpm, to obtain an antibacterial and antimicrobial polyamide fiber;

[0062] The mass ratio of dopamine-modified carbon nanotubes, metal salt ions, toughening agent and polyamide masterbatch is 5:1:5:100; the metal salt ions are zinc chloride; and the toughening agent is nano-calcium carbonate with a particle size of 20 nm.

[0063] Comparative Example 1

[0064] A method for preparing antibacterial and antimicrobial polyamide fiber, specifically comprising the following preparation steps:

[0065] S1. A multi-walled carbon nanotube is subjected to acid oxidation treatment, and then modified with dopamine hydrochloride to prepare dopamine-modified carbon nanotubes. The specific steps are as follows:

[0066] S11, adding a multi-walled carbon nanotube raw material to a mixed acid solution at a mass volume ratio of 1 g: 8 mL, ultrasonically dispersing for 30 minutes, then raising the system temperature to 60° C., treating for 2 hours, cooling to room temperature, filtering, and washing the filtered product with deionized water until the pH value of the washing solution is neutral, to obtain acid-oxidized multi-walled carbon nanotubes;

[0067] The mixed acid solution is composed of concentrated sulfuric acid and concentrated nitric acid; wherein the volume ratio of concentrated sulfuric acid to concentrated nitric acid is 3:1;

[0068] S12, placing the acid-oxidized multi-walled carbon nanotubes obtained in step S11 in deionized water at a mass volume ratio of 1 g:10 mL, adding EDC, NHS and dopamine hydrochloride, and stirring at a rate of 30 rpm for 20 hours at room temperature and a nitrogen atmosphere to obtain dopamine-modified carbon nanotubes;

[0069] The frequency of ultrasonic treatment is 20 KHz, the power is 300 W, and the mass ratio of acidified multi-walled carbon nanotubes, EDC, NHS and dopamine hydrochloride is 1:0.1:0.05:0.2.

[0070] Afterwards, the obtained dopamine-modified carbon nanotubes are mixed with metal salt ions, toughening agents and polyamide masterbatches to prepare the antibacterial and antimicrobial polyamide fibers. The specific method is as in step S2 of Example 1.

[0071] Comparative Example 2

[0072] A method for preparing antibacterial and antimicrobial polyamide fiber, specifically comprising the following preparation steps:

[0073] S1, subjecting multi-walled carbon nanotubes to acid oxidation treatment, and then modifying them with a surfactant to prepare modified carbon nanotubes, the specific steps being:

[0074] S11, adding a multi-walled carbon nanotube raw material to a mixed acid solution at a mass volume ratio of 1 g: 8 mL, ultrasonically dispersing for 30 minutes, then raising the system temperature to 60° C., treating for 2 hours, cooling to room temperature, filtering, and washing the filtered product with deionized water until the pH value of the washing solution is neutral, to obtain acid-oxidized multi-walled carbon nanotubes;

[0075] The mixed acid solution is composed of concentrated sulfuric acid and concentrated nitric acid; wherein the volume ratio of concentrated sulfuric acid to concentrated nitric acid is 3:1;

[0076] S12, mixing the acid-oxidized multi-walled carbon nanotubes obtained in step S11 with a surfactant at a mass ratio of 1:0.8, dispersing the system in deionized water at a mass volume ratio of 1 g:10 mL, ultrasonically treating for 1 hour, and then washing with deionized water to obtain modified carbon nanotubes;

[0077] The frequency of the ultrasonic treatment is 20 KHz and the power is 300 W; the surfactant is obtained by mixing sodium dodecylbenzene sulfonate, sodium octyl sulfonate and octyltrimethylammonium chloride in a mass ratio of 1:1:0.1.

[0078] Then, the obtained modified carbon nanotubes are mixed with metal salt ions, toughening agent and polyamide masterbatch to prepare the antibacterial and antimicrobial polyamide fiber. The specific method is as in step S2 of Example 1.

[0079] Comparative Example 3

[0080] A method for preparing antibacterial and antimicrobial polyamide fiber, specifically comprising the following preparation steps:

[0081] S1. Acid oxidation treatment is performed on multi-walled carbon nanotubes to prepare modified carbon nanotubes, the specific steps being:

[0082] The multi-walled carbon nanotube raw material was added to the mixed acid solution at a mass volume ratio of 1 g: 8 mL, and ultrasonically dispersed for 30 minutes, then the system temperature was raised to 60°C, and after treatment for 2 hours, it was cooled to room temperature and filtered, and the filtered product was washed with deionized water until the pH value of the washing solution was neutral, thereby obtaining acid-oxidized multi-walled carbon nanotubes;

[0083] The mixed acid solution is composed of concentrated sulfuric acid and concentrated nitric acid; the volume ratio of concentrated sulfuric acid to concentrated nitric acid is 3:1.

[0084] Then, the obtained acid-oxidized multi-walled carbon nanotubes are mixed with metal salt ions, toughening agent and polyamide masterbatch to prepare the antibacterial and antimicrobial polyamide fiber. The specific method is as shown in step S2 of Example 1.

[0085] Comparative Example 4

[0086] The difference between this comparative example and Example 1 is that the step S2 of this comparative example is:

[0087] The dopamine-modified carbon nanotubes, toughening agent and polyamide masterbatch obtained in step S1 are mixed, and then the system temperature is raised to 280° C. and maintained for 10 minutes, and then the obtained melt is melt-spun, with a spinneret diameter of 0.3 mm and a winding speed of 20 rpm, to obtain an antibacterial and antimicrobial polyamide fiber;

[0088] Among them, the mass ratio of dopamine-modified carbon nanotubes, toughening agent and polyamide masterbatch is 0.6:1:100;

[0089] The remaining steps (such as steps S11 and S12) are the same as those in Example 1.

[0090] Comparative Example 5

[0091] The difference between this comparative example and Example 1 is that in step S1, the surfactant is obtained by mixing sodium dodecylbenzene sulfonate and sodium octyl sulfonate in a mass ratio of 1:1.1. The remaining steps are the same as in Example 1.

[0092] Performance Testing

[0093] Now the mechanical properties of the polyamide fibers prepared in Examples 1-3 and Comparative Examples 1-5 are tested. 10 cm of the polyamide fibers prepared in different groups are taken as samples. The samples prepared in different groups are tested for Young's modulus, tensile strength, and elongation at break using a fiber tensile tester, and the tensile rate of the fiber tensile tester is set to 10 mm / min. Each sample is tested 5 times, and the average value is recorded. The specific performance test results are shown in Table 1 below:

[0094] Table 1

[0095] Group Young's modulus(GPa) Tensile strength(Mpa) Elongation at break (%) Example 1 0.53 108.3 47.6 Example 2 0.57 112.3 49.6 Example 3 0.55 110.0 47.7 Comparative Example 1 0.51 106.3 47.0 Comparative Example 2 0.50 104.2 46.3 Comparative Example 3 0.48 95.9 26.5 Comparative Example 4 0.48 100.6 35.9 Comparative Example 5 0.52 105.3 46.2

[0096] From the results shown in Table 1 above, it can be seen that the mechanical properties including Young's modulus, tensile strength and elongation at break of the polyamide fibers prepared in Examples 1-3 of the present application are significantly better than those of the products prepared in Comparative Examples 1-5, that is, within the technical solution defined in the present application, the performance of the polyamide fibers prepared is excellent.

[0097] The polyamide fibers prepared in Examples 1-3 and Comparative Examples 1-5 are now tested for their antibacterial effects. The killing effects of the fibers on Gram-positive bacteria, Gram-negative bacteria and fungi were measured. Bacillus, Escherichia coli and Candida albicans were taken as test strains. The polyamide fibers prepared in different groups were washed 5 times with deionized water and dried naturally to obtain fiber samples. 5 mL of sterilized culture medium was poured into a 25 mL sterilized culture dish for solidification. In the solidified culture medium, a hole was made in the agar culture medium using a sterile steel drill with a pore size of 6 mm. The microbial suspension was evenly applied to the surface of the solidified medium with a sterile swab, and 0.1 g of fiber sample was added to each well with the help of a micropipette. The plate was incubated at 37 ° C for 24 hours to achieve antibacterial activity, and at 25 ° C for 48 hours to obtain antifungal activity. Five readings were obtained for each sample and averaged, and the test results are shown in Table 2 below.

[0098] Table 2

[0099] Group Bacillus inhibition rate (%) Escherichia coli inhibition rate (%) Candida albicans inhibition rate (%) Example 1 96.8 98.9 98.3 Example 2 96.3 99.8 98.7 Example 3 96.5 99.1 98.5 Comparative Example 1 94.8 96.8 96.0 Comparative Example 2 95.2 97.0 96.3 Comparative Example 3 86.9 89.0 88.7 Comparative Example 4 90.3 92.5 91.8 Comparative Example 5 96.0 97.8 97.1

[0100] From the results in Table 2, it can be seen that the polyamide fiber prepared in Example 2 shows good antibacterial effects on Bacillus, Escherichia coli and Candida albicans, among which the inhibitory effect on Escherichia coli is the best. From the results in Comparative Examples 1 and 5, it can be seen that after the multi-walled carbon nanotubes are modified with a surfactant, the dispersion of the multi-walled carbon nanotube material in the system is promoted, and the antibacterial enhancement effect of the multi-walled carbon nanotubes on the polyamide fiber can be further improved. From the results in Comparative Examples 2 and 4, it can be seen that the use of metal salt ions can play a synergistic role with dopamine-modified carbon nanotubes in the antibacterial performance of polyamide fibers.

[0101] In the description of the specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0102] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the invention or exceed the scope defined by the claims, they shall all fall within the protection scope of the present invention.

Claims

1. A method for preparing antibacterial and antimicrobial polyamide fiber, characterized in that: The method comprises the following preparation steps: S1, subjecting multi-walled carbon nanotubes to acid oxidation treatment, and then sequentially modifying them using a surfactant and dopamine hydrochloride to prepare dopamine-modified carbon nanotubes; S2. The dopamine-modified carbon nanotubes, metal salt ions, toughening agent and polyamide masterbatch obtained in step S1 are mixed, and then the system temperature is increased to 280-290° C. and maintained for 10-15 minutes, and then the obtained melt is melt-spinned to obtain an antibacterial and antimicrobial polyamide fiber.

2. The method for preparing an antibacterial and antimicrobial polyamide fiber according to claim 1, characterized in that: In step S1, dopamine-modified carbon nanotubes are prepared by the following steps: S11, adding the multi-walled carbon nanotube raw material to the mixed acid solution, ultrasonically dispersing, then raising the system temperature to 60-80° C., treating for 2-3 hours, cooling to room temperature, filtering, washing the filtered product, and obtaining acid-oxidized multi-walled carbon nanotubes; S12. Mix the acid-oxidized multi-walled carbon nanotubes obtained in step S11 with a surfactant, disperse the system in deionized water, perform ultrasonic treatment, then wash, resuspend in deionized water, add EDC, NHS and dopamine hydrochloride, and stir for 20-30 hours at room temperature in an inert gas atmosphere to obtain dopamine-modified carbon nanotubes.

3. The method for preparing an antibacterial and antimicrobial polyamide fiber according to claim 2, characterized in that: In step S11, the mixed acid solution is composed of concentrated sulfuric acid and concentrated nitric acid, wherein the volume ratio of concentrated sulfuric acid to concentrated nitric acid is 3:

1.

4. The method for preparing an antibacterial and antimicrobial polyamide fiber according to claim 2, characterized in that: In step S12, the frequency of ultrasonic treatment is 20-25KHz and the power is 300-500W.

5. The method for preparing an antibacterial and antimicrobial polyamide fiber according to claim 2, characterized in that: In step S12, the mass ratio of acidified multi-walled carbon nanotubes, EDC, NHS and dopamine hydrochloride is (1-6):(0.1-0.3):(0.05-0.2):(0.2-1).

6. The method for preparing an antibacterial and antimicrobial polyamide fiber according to claim 2, characterized in that: In step S12, the surfactant is obtained by mixing sodium dodecylbenzene sulfonate, sodium octyl sulfonate and octyltrimethylammonium chloride in a mass ratio of 1:1:(0.1-1).

7. The method for preparing an antibacterial and antimicrobial polyamide fiber according to claim 1, characterized in that: In step S2, the mass ratio of dopamine-modified carbon nanotubes, metal salt ions, toughening agent and polyamide masterbatch is (0.5-5):(0.1-1):(1-5):

100.

8. The method for preparing an antibacterial and antimicrobial polyamide fiber according to claim 1, characterized in that: In step S2, the metal salt ion is at least one of copper chloride, copper sulfate, silver nitrate, zinc sulfate, magnesium sulfate and zinc chloride.

9. The method for preparing an antibacterial and antimicrobial polyamide fiber according to claim 1, characterized in that: In step S2, the toughening agent is at least one of a nanoparticle toughening agent, a polyolefin toughening agent, a rubber elastomer toughening agent, and a core-shell copolymer toughening agent.

10. A polyamide fiber obtained by the method for preparing antibacterial and antimicrobial polyamide fibers according to any one of claims 1 to 9.