Chitosan / nanoclay antibacterial nonwoven fabric and preparation method and application thereof

Abstract

The application discloses a kind of chitosan / nano clay antibacterial non-woven fabrics and its preparation method and application.The method is: under the state of stirring, chitosan or its derivative is stirred and dissolved, and a certain amount of nano clay is added to obtain a mixed solution;Then the mixed solution is loaded on non-woven fabric (such as soaking, spraying, smearing), and the chitosan / nano clay antibacterial non-woven fabric is obtained after drying.The cloth has excellent antibacterial properties, including gram-positive bacteria, negative bacteria and fungi, and good softness and air permeability, and can be used for medical or disposable sanitary products such as masks, protective clothing, paper diapers.Compared with the prior art, the preparation method is simple and easy to operate, and has good application prospect.

Description

Technical Field

[0001] This invention belongs to the field of biomedical materials, specifically relating to a chitosan / nanoclay antibacterial nonwoven fabric, its preparation method, and its application. Background Technology

[0002] In recent years, bacterial diseases such as influenza A and pneumonia have seriously endangered people's health. To better prevent and control bacteria, researchers are constantly searching for and developing safer and more effective antibacterial materials. In the fields of medical and disposable hygiene products, nonwoven fabrics, which are easy to cut and breathable, have a wide range of applications, such as masks, protective clothing, and diapers. Nonwoven fabrics with optimized antibacterial properties not only improve product quality but also better meet the protective needs of daily life (Yang N, et al. Mango peel extract mediated novel route for synthesis of silver nanoparticles and antibacterial application of silver nanoparticles loaded onto non-woven fabrics. Ind Crops Prod. 2013, 48, 81-88). However, the existing silver antibacterial nonwoven fabric preparation process is cumbersome and costly, making it difficult to apply on a large scale (Gao YN, et al. Multifunctional cotton non-woven fabrics coated with silver nanoparticles and polymers for antibacterial, superhydrophobic and high performance microwave shielding. J Colloid Inter Sci. 2021, 582, 112-123).

[0003] As a natural polycationic polysaccharide, chitosan has the advantages of abundant sources, non-toxicity, and good compatibility, and can effectively inhibit the growth of various bacteria and fungi. However, its good film-forming properties make pure chitosan (or its derivatives) nonwoven fabrics less soft and harder, making them unsuitable for direct skin contact.

[0004] Naturally derived nanoclay is a layered silicate with a high specific surface area, good adsorption properties, and lower cost. Furthermore, the organically modified product exhibits superior antibacterial properties. Applying it to antibacterial nonwoven fabrics can effectively improve the fabric's softness. However, even modified and optimized nanoclay cannot meet the requirement of a high antibacterial rate. Therefore, by adjusting the ratio of the two materials, it is possible to improve softness and reduce costs while ensuring the antibacterial properties of the nonwoven fabric. Summary of the Invention

[0005] In order to overcome the shortcomings of the existing technology, the purpose of this invention is to provide a chitosan / nanoclay antibacterial nonwoven fabric, its preparation method and application.

[0006] The objective of this invention is achieved by at least one of the following technical solutions.

[0007] This invention provides a chitosan / nanoclay antibacterial nonwoven fabric and its preparation method. The method utilizes the physical interaction between nanoclay and chitosan or its derivatives, dissolving and mixing them in a certain proportion to obtain a chitosan or its derivative / nanoclay mixed solution; then, the chitosan or its derivative-nanoclay antibacterial agent is attached to the nonwoven fabric in a specific manner to achieve antibacterial effect.

[0008] The present invention provides a chitosan / nanoclay antibacterial nonwoven fabric, which is specifically a nonwoven fabric with a soft texture, good breathability and excellent antibacterial properties. This nonwoven fabric has an inhibitory effect on Gram-positive bacteria, Gram-negative bacteria and fungi.

[0009] This invention provides a chitosan / nanoclay antibacterial nonwoven fabric and its preparation method, comprising the following steps:

[0010] (1) Dissolve chitosan in solvent 1 or dissolve water-soluble chitosan derivatives in water, then add nano clay and stir evenly to obtain a chitosan or its derivatives / nano clay mixed solution.

[0011] (2) Load the mixed solution onto the nonwoven fabric and dry it to obtain the chitosan / nanoclay antibacterial nonwoven fabric.

[0012] Further, the water-soluble chitosan derivative in step (1) includes one or more of chitosan quaternary ammonium salt, carboxymethyl chitosan, hydroxypropyl chitosan and hydroxymethyl chitosan.

[0013] Preferably, the chitosan or water-soluble chitosan derivative mentioned in step (1) is a dry powder of chitosan or water-soluble chitosan derivative, and its purity level is analytical grade.

[0014] Further, the chitosan or water-soluble chitosan derivative mentioned in step (1) is purified chitosan or water-soluble chitosan derivative; the specific purification method is as follows:

[0015] Under stirring, chitosan is dissolved in solvent 1 or a water-soluble chitosan derivative is dissolved in water and mixed evenly to obtain a chitosan or derivative solution; the chitosan or derivative solution is dialyzed and freeze-dried to obtain purified chitosan or derivative.

[0016] Preferably, solvent 1 is one or more of acetic acid, formic acid, and hydrochloric acid, with a pH value of 4-6; the water-soluble chitosan derivative is soluble in pure water; and the mass percentage concentration of chitosan or its derivative in solvent 1 or pure water is 0.5-5%.

[0017] Preferably, the stirring time is 30-60 minutes.

[0018] Preferably, the dialysis is performed in a pure water environment, the dialysis time is 3-5 days, and the molecular weight cutoff of the dialysis bag is 1000-3500D.

[0019] Further, the nano-clay mentioned in step (2) includes one or more of lithium saponite, kaolin, montmorillonite, organically modified lithium saponite, and organically modified montmorillonite.

[0020] Preferably, the organically modified lithium saponite is lithium saponite modified with CTAB (hexadecyltrimethylammonium bromide); the organically modified montmorillonite is montmorillonite modified with CTAB (hexadecyltrimethylammonium bromide).

[0021] Preferably, the preparation method of the organic modified lithium saponite (or montmorillonite) specifically involves preparing a 5g suspension of lithium saponite (or montmorillonite) with a mass percentage concentration of 2%, stirring at high speed for 30 minutes to disperse it evenly, and placing it in a microwave radiation instrument; dissolving 1g of CTAB (hexadecyltrimethylammonium bromide) in 25mL of deionized water, and adding it dropwise to the suspension at 800W and 85℃ for microwave reaction for 60 minutes; washing the product three times with distilled water by centrifugation (centrifuge speed 4000rpm, centrifugation time 5min), and collecting the centrifuged product to obtain the organic modified lithium saponite (or montmorillonite).

[0022] Further, the mass ratio of chitosan or its derivative to nanoclay in step (1) is 10:1 to 1:10.

[0023] Further, in step (1), solvent 1 is one or more of acetic acid, formic acid, and hydrochloric acid, with a pH value of 4-6; the water-soluble chitosan derivative is soluble in pure water; the mass percentage concentration of chitosan or its derivative in solvent 1 or pure water is 0.5-5%.

[0024] Furthermore, the stirring time in step (1) is 30-60 min.

[0025] Further, the loading in step (2) includes one or more of the following: completely immersing the nonwoven fabric in the mixed solution; uniformly spraying the mixed solution onto the nonwoven fabric; and uniformly adding the mixed solution to the nonwoven fabric using a dropper.

[0026] Preferably, the soaking time is 30-60 minutes.

[0027] Furthermore, the drying temperature in step (2) is 30-70℃, and the drying time is 3-24h;

[0028] Further, the solid content of the mixed solution in step (2) is 1:1 to 1:4 of the mass of the nonwoven fabric.

[0029] This invention provides a chitosan / nanoclay antibacterial nonwoven fabric prepared by any of the above-described methods.

[0030] The present invention also provides the application of the above-mentioned chitosan / nanoclay antibacterial nonwoven fabric in biomedical materials.

[0031] The preparation method provided by the present invention involves mixing a certain proportion of nano-clay with a chitosan or its derivative solution to obtain a chitosan or its derivative-nano-clay mixed solution, then attaching the chitosan (derivative)-nano-clay composite antibacterial agent to a nonwoven fabric in a certain manner, and finally drying the fabric.

[0032] This invention aims to reduce material costs by using inexpensive nanoclay to partially replace chitosan or its derivatives through the physical interaction between nanoclay and chitosan and its derivatives, without affecting the antibacterial effect and softness. Furthermore, the resulting nonwoven fabric exhibits good softness, breathability, and antibacterial properties, making it a green antibacterial nonwoven fabric with potential clinical applications.

[0033] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0034] (1) The preparation method of the green antibacterial nonwoven fabric provided by the present invention is simple and easy to implement, the preparation process is clean and green, and the requirements for equipment and environment are not high, and the cost is low.

[0035] (2) The green antibacterial nonwoven fabric provided by the present invention is soft in texture and has good breathability;

[0036] (3) The green antibacterial nonwoven fabric provided by the present invention utilizes the interaction between chitosan or its derivatives and nano clay to construct a system of synergistic antibacterial action, giving full play to its antibacterial advantages and showing significant inhibitory effects on Gram-positive bacteria, Gram-negative bacteria and fungi.

[0037] (4) The green antibacterial nonwoven fabric provided by the present invention has a simple process and low energy consumption, and can be used for large-scale industrial production, expanding its application in medical or disposable hygiene products. Attached Figure Description

[0038] Figure 1 The bar chart shows the inhibition rate of the sample in Example 1 against different bacterial species.

[0039] Figure 2 The bar chart shows the inhibition rate of Staphylococcus aureus against samples from Examples 2, 3, and 4 (from left to right: carboxymethyl chitosan / lithium saponite nonwoven fabric, hydroxypropyl chitosan / montmorillonite nonwoven fabric, hydroxymethyl chitosan / organically modified montmorillonite nonwoven fabric).

[0040] Figure 3 The image shows the results of the heart-shaped hanging height measurement of the sample in Example 1, ordinary non-woven fabric, and pure chitosan quaternary ammonium salt fabric. Detailed Implementation

[0041] The following examples further illustrate specific implementations of the present invention, but the implementation and protection of the present invention are not limited thereto. It should be noted that any processes not specifically described below are those that can be implemented or understood by those skilled in the art by referring to existing technology. Reagents or instruments whose manufacturers are not specified are considered to be conventional products that can be purchased commercially.

[0042] Example 1

[0043] Add 10g of chitosan quaternary ammonium salt powder to 200mL of pure water (solution mass percentage concentration is 5%), stir for 30min until completely dissolved, dialyze for 5 days using a dialysis bag with a molecular weight cutoff of 3500D, freeze dry to obtain purified chitosan quaternary ammonium salt.

[0044] Add 1g of purified chitosan quaternary ammonium salt to 100mL of pure water and stir for 40min until completely dissolved. Add 2g of organic modified lithium soapstone (the mass ratio of chitosan quaternary ammonium salt to nano clay is 1:2) and continue stirring for 30min to obtain a mixed solution of chitosan quaternary ammonium salt / organic modified lithium soapstone.

[0045] Cut 12g of nonwoven fabric (the sum of the masses of quaternized chitosan and organically modified lithium saponite: the mass of nonwoven fabric = 1:4) and completely immerse it in the mixed solution for 30 minutes. Then remove it and place it in a hot air drying oven and dry it at 70℃ for 3 hours to obtain the quaternized chitosan / organically modified lithium saponite antibacterial nonwoven fabric.

[0046] The antibacterial properties of nonwoven fabric were tested by co-culturing 0.01g of nonwoven fabric sample with different types of bacterial suspensions (Staphylococcus aureus, Escherichia coli, and Candida albicans) for 4 hours. The bacterial suspensions were then diluted and plated. After incubation at suitable temperatures for a period of time (Staphylococcus aureus and Escherichia coli at 37℃ for 24 hours, and Candida albicans at 27℃ for 48 hours), the colony counts were recorded, and the corresponding inhibition rate formulas are shown below.

[0047]

[0048] have to Figure 1 The bar chart showing the antibacterial rate indicates that this nonwoven fabric has good antibacterial properties, with an inhibition rate of over 99% against Staphylococcus aureus, Escherichia coli, and Candida albicans.

[0049] Example 2

[0050] Add 10g of carboxymethyl chitosan powder to 2000mL of pure water (solution mass percentage concentration is 0.5%), stir for 40min until completely dissolved, dialyze using a dialysis bag with a molecular weight cutoff of 1000D for 4 days, freeze dry to obtain purified carboxymethyl chitosan.

[0051] Add 1g of purified carboxymethyl chitosan to 200mL of pure water and stir for 50min until completely dissolved. Add 5g of lithium saponite (the mass ratio of carboxymethyl chitosan to lithium saponite is 1:5) and continue stirring for 30min to obtain a mixed solution of carboxymethyl chitosan / lithium saponite.

[0052] Cut 18g of nonwoven fabric (the sum of the masses of carboxymethyl chitosan and lithium saponite: the mass of the nonwoven fabric = 1:3) and completely immerse it in the mixed solution for 60 minutes. Then remove it and place it in a hot air drying oven and dry it at 30°C for 24 hours to obtain the carboxymethyl chitosan / lithium saponite antibacterial nonwoven fabric.

[0053] Example 3

[0054] Add 10g of hydroxypropyl chitosan powder to 250mL of pure water (solution mass percentage concentration is 4%), stir for 60min until completely dissolved, dialyze using a dialysis bag with a molecular weight cutoff of 2000D for 3 days, freeze dry to obtain purified hydroxypropyl chitosan.

[0055] Add 1g of purified hydroxypropyl chitosan to 20mL of pure water and stir for 60min until completely dissolved. Add 0.5g of montmorillonite (the mass ratio of hydroxypropyl chitosan to montmorillonite is 2:1) and continue stirring for 50min to obtain a hydroxypropyl chitosan / montmorillonite mixed solution.

[0056] Cut 3g of nonwoven fabric (the sum of the masses of hydroxypropyl chitosan and montmorillonite: the mass of nonwoven fabric = 1:2), and use a dropper to evenly add the mixed solution to the surface of the nonwoven fabric. Then remove it and place it in a hot air drying oven, and dry it at 40℃ for 18h to obtain the hydroxypropyl chitosan / montmorillonite antibacterial nonwoven fabric.

[0057] Example 4

[0058] Add 10g of hydroxymethyl chitosan powder to 1000mL of pure water (solution mass percentage concentration is 1%), stir for 50min until completely dissolved, dialyze using a dialysis bag with a molecular weight cutoff of 3500D for 4 days, freeze dry to obtain purified hydroxymethyl chitosan.

[0059] Add 1g of purified hydroxymethyl chitosan to 50mL of pure water and stir for 30min until completely dissolved. Add 1g of organically modified montmorillonite (the mass ratio of hydroxymethyl chitosan to organically modified montmorillonite is 1:2) and continue stirring for 30min to obtain a hydroxymethyl chitosan / organically modified montmorillonite mixed solution.

[0060] Cut 2g of nonwoven fabric (the sum of the masses of hydroxymethyl chitosan and organically modified montmorillonite: the mass of nonwoven fabric = 1:1), and spray the mixed solution evenly onto both sides of the nonwoven fabric using a spray bottle. Then remove it and place it in a hot air drying oven, and dry it at 60℃ for 8 hours to obtain the hydroxymethyl chitosan / organically modified montmorillonite nonwoven fabric.

[0061] Example 5

[0062] Add 10g of chitosan powder to 500mL of pH=5 acetic acid solution (solution mass percentage concentration is 2%), stir for 60min until completely dissolved, dialyze using a dialysis bag with a molecular weight cutoff of 2000D for 4 days, freeze dry to obtain purified chitosan.

[0063] Add 1g of purified chitosan to 100mL of pH=6 acetic acid solution and stir for 60min until completely dissolved. Add 1g of kaolin (the mass ratio of chitosan to kaolin is 1:1) and continue stirring for 50min to obtain a chitosan / kaolin mixed solution.

[0064] Cut 4g of nonwoven fabric (the ratio of the sum of the masses of chitosan and kaolin to the mass of the nonwoven fabric is 1:2), and spray the mixed solution evenly onto both sides of the nonwoven fabric using a spray bottle. Then, remove it and place it in a hot air drying oven, and dry it at 50℃ for 10 hours to obtain the chitosan / kaolin antibacterial nonwoven fabric.

[0065] Example 6

[0066] 10g of chitosan powder was added to 400mL of pH=6 hydrochloric acid solution (solution mass percentage concentration of 2.5%), stirred for 50min until completely dissolved, dialyzed for 4 days using a dialysis bag with a molecular weight cutoff of 3000D, and then freeze-dried to obtain purified chitosan.

[0067] Add 1g of purified chitosan to 100mL of pH=5 formic acid solution and stir for 50min until completely dissolved. Add 10g of organically modified montmorillonite (the mass ratio of chitosan to organically modified montmorillonite is 1:10) and continue stirring for 50min to obtain a chitosan / organically modified montmorillonite mixed solution.

[0068] Cut 6g of nonwoven fabric (the sum of the masses of chitosan and organically modified montmorillonite: the mass of nonwoven fabric = 1:2), and use a spray bottle to evenly spray the mixed solution onto both sides of the nonwoven fabric. Then remove it and place it in a hot air drying oven, and dry it at 60℃ for 8 hours to obtain the chitosan / organically modified montmorillonite antibacterial nonwoven fabric.

[0069] Example 7

[0070] 10g of chitosan powder was added to 250mL of formic acid solution with pH=5.5 (solution mass percentage concentration of 4%), stirred for 60min until completely dissolved, dialyzed for 5 days using a dialysis bag with a molecular weight cutoff of 3000D, and then freeze-dried to obtain purified chitosan.

[0071] Add 5g of purified chitosan to 100mL of pH=6 acetic acid solution and stir for 50min until completely dissolved. Add 0.5g of organic modified lithium saponite (the mass ratio of chitosan to organic modified lithium saponite is 10:1) and continue stirring for 40min to obtain a chitosan / organic modified lithium saponite mixed solution.

[0072] Cut 12g of nonwoven fabric (the sum of the masses of chitosan and organically modified lithium saponite to the mass of nonwoven fabric = 1:4) and completely immerse it in the mixed solution for 40 minutes. Then remove it and place it in a hot air drying oven and dry it at 50°C for 6 hours to obtain the chitosan / organically modified lithium saponite antibacterial nonwoven fabric.

[0073] Effect verification

[0074] Figure 1A bar chart is provided showing the inhibition rates of the quaternized chitosan / organically modified lithium soapstone antibacterial nonwoven fabric prepared in Example 1 against Staphylococcus aureus, Escherichia coli, and Candida albicans. The mass fractions of quaternized chitosan and organically modified lithium soapstone were both 1%, and the mass ratio of antibacterial agent to nonwoven fabric was 1:1. The component contents of each group of samples were consistent. Samples were cut into 0.01g pieces, and then 5mL of bacterial solution was added and cultured under suitable conditions for 4h. The cultured bacterial solution was then diluted to 1×10⁻⁶ with 0.9% physiological saline. 4 CFU / mL, and 100 μL of bacterial suspension was plated separately. The plated plates were incubated in an incubator, and after a period of time, the colony count was counted to determine the inhibition rate. Compared with the control group, the colony count in the sample group was significantly reduced. Calculations showed that the nonwoven fabric exhibited an inhibition rate of over 99% against Staphylococcus aureus, Escherichia coli, and Candida albicans, demonstrating excellent bactericidal effects.

[0075] Figure 2 Bar charts are provided showing the inhibition rates of carboxymethyl chitosan / lithium soapstone, hydroxypropyl chitosan / montmorillonite, and hydroxymethyl chitosan / organically modified montmorillonite antibacterial nonwoven fabrics against Staphylococcus aureus prepared in Examples 2, 3, and 4. 0.01 g of sample was cultured with Staphylococcus aureus bacterial suspension according to the above method, spread, and counted. Compared with the blank group, the colony count in the sample groups was significantly reduced, and the inhibition rate against Candida albicans was greater than 99%, all exhibiting good antibacterial activity.

[0076] Figure 3 The softness of the fabric was tested using the heart-shaped drape method. The heart-shaped method can be used to test lightweight fabrics. The sample size is 2cm × 25cm, with a mark at each end at 2.5cm. The effective length of the sample is 20cm. The sample is clamped at the marked points using a horizontal clamp, forming a heart shape under its own weight. After 1 minute, the distance from the top of the horizontal clamp to the bottom of the heart shape is measured, representing the softness of the fabric, called the drape height. The greater the drape height, the softer the fabric. The pure chitosan quaternary ammonium salt fabric was prepared by replacing the organically modified lithium soapstone in Example 1 with chitosan quaternary ammonium salt, while keeping other procedures unchanged. As shown in the figure, the chitosan quaternary ammonium salt / organically modified lithium soapstone antibacterial nonwoven fabric has better softness than the pure chitosan quaternary ammonium salt fabric. Therefore, using nano-clay composites with chitosan (or its derivatives) helps improve the softness of the fabric.

[0077] The above embodiments are merely preferred embodiments of the present invention and are only used to explain the present invention, not to limit the present invention. Any changes, substitutions, modifications, etc., made by those skilled in the art without departing from the spirit and essence of the present invention should be within the protection scope of the present invention.

Claims

1. A method for preparing a chitosan / nanoclay antibacterial nonwoven fabric, characterized by, Includes the following steps: (1) Dissolve the water-soluble chitosan derivative in pure water, then add nano clay and stir evenly to obtain a chitosan derivative / nanoclay mixed solution; The water-soluble chitosan derivative is a purified water-soluble chitosan derivative; the specific purification method is as follows: under stirring, the water-soluble chitosan derivative is dissolved in water and mixed evenly to obtain a chitosan derivative solution; the chitosan derivative solution is dialyzed and freeze-dried to obtain the purified chitosan derivative. The dialysis is performed in a pure water environment, and the dialysis time is 3-5 days. The molecular weight cutoff of the dialysis bag is 1000-3500D. The chitosan derivative has a mass percentage concentration of 0.5-5% in pure water; the stirring time is 30-60 min. The nano-clay in step (1) includes one or more of lithium saponite, kaolin, montmorillonite, organically modified lithium saponite, and organically modified montmorillonite; the mass ratio of the chitosan derivative to the nano-clay in step (1) is 10:1 to 1:

10. (2) Load the mixed solution onto a nonwoven fabric and dry it to obtain the chitosan / nanoclay antibacterial nonwoven fabric; The solid content of the mixed solution in step (2) is 1:1 to 1:4 of the mass of the nonwoven fabric; the drying temperature in step (2) is 30-70℃ and the drying time is 3-24h.

2. The method for preparing chitosan / nanoclay antibacterial nonwoven fabric according to claim 1, characterized in that, The water-soluble chitosan derivative in step (1) includes one or more of chitosan quaternary ammonium salt, carboxymethyl chitosan, hydroxypropyl chitosan and hydroxymethyl chitosan.

3. The method for preparing chitosan / nanoclay antibacterial nonwoven fabric according to claim 1, characterized in that, The loading in step (2) includes completely immersing the nonwoven fabric in the mixed solution for 30-60 minutes; uniformly spraying the mixed solution onto the nonwoven fabric; and uniformly adding the mixed solution to the nonwoven fabric using a dropper.

4. A chitosan / nanoclay antibacterial nonwoven fabric prepared by the preparation method according to any one of claims 1-3.

5. The application of the chitosan / nanoclay antibacterial nonwoven fabric according to claim 4 in biomedical materials.

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