Titanium dioxide modified silk and preparation method thereof

Abstract

The invention relates to the technical field of silk modification, in particular to titanium dioxide modified silk and a preparation method thereof.The titanium dioxide modified silk is formed by treating silk through titanium dioxide modification liquid, and the titanium dioxide modification liquid comprises nanometer titanium dioxide, a dispersing agent, a cross-linking agent, a functional auxiliary, composite nanoparticles and deionized water; the coating comprises the following components in parts by mass: 5-15 parts of nano titanium dioxide, 1-5 parts of a dispersing agent, 2-8 parts of a cross-linking agent, 0.5-3 parts of a functional auxiliary agent, 1-4 parts of composite nanoparticles and 68-90 parts of deionized water. According to the titanium dioxide modified silk and the preparation method thereof, a multi-stage antibacterial system is formed through a functional auxiliary agent and composite nanoparticles, chitosan quaternary ammonium salt destroys bacterial cell membranes to achieve rapid bacteriostasis, nano-silver achieves long-acting sterilization by means of the slow release effect of metal ions, and nano-titanium dioxide decomposes bacterial remains through photocatalysis; the antibacterial rate on escherichia coli and staphylococcus aureus is stable, and the problems that a traditional single antibacterial agent is prone to generating drug resistance and short in time effect are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of silk modification, in particular to titanium dioxide-modified silk and a preparation method thereof. Background Art

[0002] Silk, a natural protein fiber, boasts excellent breathability, moisture absorption, and biocompatibility, and is widely used in textiles, medicine, and beauty. However, natural silk also has some drawbacks, such as poor antibacterial properties, weak UV protection, and mechanical properties that require improvement, which limit its application in some specialized fields. To improve the properties of silk, researchers have conducted extensive research. Modifying silk with nanomaterials is an effective approach. Titanium dioxide, a common nanomaterial, exhibits excellent antibacterial, UV-shielding, and chemical stability properties. Its application in silk modification is expected to enhance related properties. While some research has focused on titanium dioxide-modified silk, challenges remain regarding both the modification effect and the preparation process. For example, nano-titanium dioxide tends to aggregate in the modification solution, resulting in uneven dispersion on the silk surface and affecting the modification effect. Furthermore, some preparation methods are complex and costly, making them unsuitable for industrial production. Therefore, developing a simple and effective method for preparing titanium dioxide-modified silk is of great significance. Summary of the Invention

[0003] The present invention provides titanium dioxide-modified silk and a method for preparing the same. The modified silk exhibits excellent antibacterial properties, ultraviolet protection, mechanical properties, far-infrared emission, and self-cleaning properties, and the preparation method is simple and amenable to industrial production.

[0004] To achieve the above-mentioned object, the present invention provides the following technical solution: a titanium dioxide-modified silk, which is prepared by treating silk with a titanium dioxide-modifying liquid, wherein the titanium dioxide-modifying liquid comprises nano-titanium dioxide, a dispersant, a cross-linking agent, a functional additive, composite nanoparticles and deionized water, wherein the weight proportions of the components are as follows: 5-15 parts of nano-titanium dioxide, 1-5 parts of dispersant, 2-8 parts of cross-linking agent, 0.5-3 parts of functional additive, 1-4 parts of composite nanoparticles and 68-90 parts of deionized water; the functional additive is one of graphene quantum dots or chitosan quaternary ammonium salt; and the composite nanoparticles are a complex of nano-zinc oxide and nano-silver, and the mass ratio of nano-zinc oxide to nano-silver is 3:1.

[0005] Preferably, the average particle size of the nano-titanium dioxide is 10-50 nm.

[0006] Preferably, the dispersant is at least one of sodium lauryl sulfate, polyethylene glycol or a silane coupling agent.

[0007] Preferably, the cross-linking agent is at least one of glutaraldehyde, citric acid or epoxy resin.

[0008] Preferably, when the cross-linking agent is glutaraldehyde, the pH value during the cross-linking reaction is controlled between 6 and 8 to promote the occurrence of intermolecular cross-linking reaction and enhance the cross-linking effect.

[0009] Preferably, when preparing the composite nanoparticles, nano zinc oxide is first dispersed in an aqueous solution containing a dispersant, dispersed for 15-20 minutes under an ultrasonic power of 200-300 W, and then nano silver is added and ultrasonic dispersion is continued for 10-15 minutes to form a uniform composite nanoparticle dispersion liquid for the subsequent preparation of titanium dioxide modified liquid.

[0010] A method for preparing titanium dioxide-modified silk comprises the following steps: S1: preparing a titanium dioxide modified liquid: weighing nano-titanium dioxide, a dispersant, a cross-linking agent, a functional additive, composite nanoparticles, and deionized water in parts by mass, adding the nano-titanium dioxide, dispersant, and composite nanoparticles to the deionized water, stirring evenly, and then ultrasonically dispersing the mixture at a power of 100-200 W for 5-10 minutes, then ultrasonically dispersing the mixture at a power of 300-400 W for 10-20 minutes, then adding the cross-linking agent and functional additive, and continuing stirring for 10-20 minutes to obtain a titanium dioxide modified liquid; S2: Silk pretreatment: The silk was washed 2-3 times with deionized water and then dried in an oven at 60-80°C to constant weight; S3: Modification treatment: Place the pretreated silk into the titanium dioxide modification solution prepared in step (1), and soak it at 30-35°C for 1-2 hours, then at 40-45°C for 1-2 hours, and finally at 50-60°C for 1-3 hours, stirring every 30-60 minutes. S4: Post-treatment: The soaked silk is taken out, washed with deionized water until the washing liquid is neutral, and then placed in an oven at 60-80°C to dry to constant weight to obtain titanium dioxide-modified silk.

[0011] Preferably, during the modification process, S3 applies low-frequency stirring of 50-60 Hz to the titanium dioxide modification liquid to further promote the penetration of various components in the modification liquid into the interior of the silk and improve the modification uniformity.

[0012] Compared with the prior art, the present invention has the following beneficial effects: 1. The titanium dioxide-modified silk and its preparation method form a multi-stage antibacterial system through functional additives and composite nanoparticles. Chitosan quaternary ammonium salt destroys bacterial cell membranes to achieve rapid antibacterial effect. Nanosilver achieves long-term bactericidal effect through the sustained release of metal ions. Nanotitanium dioxide decomposes bacterial debris through photocatalysis, achieving the effect of maintaining a stable antibacterial rate against Escherichia coli and Staphylococcus aureus, solving the problem that traditional single antibacterial agents are prone to drug resistance and short efficacy.

[0013] 2. The titanium dioxide-modified silk and its preparation method form a complementary UV shielding network through nano-titanium dioxide and nano-zinc oxide, which, in combination with the protein fiber structure of silk itself, reduces UV transmittance and achieves the UPF50+ top protection standard, avoiding the defects of traditional organic sunscreens such as high volatility and strong irritation. Graphene quantum dots, with their unique conjugated structure, convert the heat energy radiated by the human body into 8-14μm far-infrared rays, allowing the modified silk to maintain a comfortable feel even in low-temperature environments and improve the warmth coefficient compared to ordinary silk fabrics.

[0014] 3. This titanium dioxide-modified silk and its preparation method utilize nano-titanium dioxide to generate hydroxyl radicals (・OH) under light conditions to decompose organic stain molecules. Combined with the hydrophilicity control of the composite nanoparticles, this improves the decomposition rate of common stains such as coffee and soy sauce while maintaining its stain removal ability, making silk fabric care easier. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0016] Figure 1 The present invention is a flow chart of the method for preparing titanium dioxide-modified silk. DETAILED DESCRIPTION

[0017] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. 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 making creative efforts are within the scope of protection of the present invention.

[0018] See also Figure 1The present invention provides a technical solution: a titanium dioxide-modified silk, which is prepared by treating silk with a titanium dioxide-modified liquid. The titanium dioxide-modified liquid includes nano-titanium dioxide, a dispersant, a cross-linking agent, a functional additive, composite nanoparticles, and deionized water. The mass fractions of each component are: 5-15 parts of nano-titanium dioxide, 1-5 parts of dispersant, 2-8 parts of cross-linking agent, 0.5-3 parts of functional additive, 1-4 parts of composite nanoparticles, and 68-90 parts of deionized water. The functional additive is either graphene quantum dots or chitosan quaternary ammonium salt. Graphene quantum dots have excellent electrical and thermal conductivity and chemical stability, which can impart far-infrared emission to silk, enhancing its thermal insulation properties. Chitosan quaternary ammonium salt has excellent antibacterial and biocompatibility, and synergistically with nano-titanium dioxide can further enhance the antibacterial effect of silk. The composite nanoparticles are a combination of nano-zinc oxide and nano-silver, with a mass ratio of 3:1. Nano-zinc oxide has certain antibacterial and UV-shielding properties, while nano-silver has a strong antibacterial effect. When combined with nano-titanium dioxide, these two can significantly enhance the overall properties of silk. This synergistic effect reduces the use of a single nanomaterial and lowers costs. The average particle size of nano-titanium dioxide is 10-50nm. This particle size range offers a large specific surface area and high activity, allowing for better bonding with silk and enhancing the modification effect. The dispersant is at least one of sodium lauryl sulfate, polyethylene glycol or a silane coupling agent. These dispersants can effectively prevent nano-titanium dioxide and the like from agglomerating in the modified liquid and improve its dispersion stability.

[0019] The cross-linking agent is at least one of glutaraldehyde, citric acid or epoxy resin. The cross-linking agent can form a chemical bond between nano-titanium dioxide and silk, thereby enhancing the bonding force between the two and improving the durability of the modified silk. The present invention also provides a method for preparing the titanium dioxide-modified silk, comprising the following steps: S1: Preparation of titanium dioxide modified liquid: Weigh nano-titanium dioxide, dispersant, cross-linking agent, functional additive, composite nanoparticles and deionized water by mass, add nano-titanium dioxide, dispersant and composite nanoparticles into deionized water, stir evenly, and then ultrasonically disperse at a power of 100-200W for 5-10 minutes, and then ultrasonically disperse at a power of 300-400W for 10-20 minutes. Use step-by-step ultrasonic dispersion, first with a lower power for preliminary dispersion to avoid direct impact of high power that may cause partial destruction of the nanoparticle structure, and then further break up the agglomerates with a higher power to make the nanoparticles more evenly dispersed. Then add the cross-linking agent and functional additive, continue stirring for 10-20 minutes, and obtain the titanium dioxide modified liquid. S2: Silk pretreatment: Wash the silk with deionized water 2-3 times to remove surface impurities, then dry it in an oven at 60-80°C to constant weight to prevent moisture from affecting the modification process.

[0020] S3: Modification treatment: The pretreated silk is placed in the titanium dioxide modification liquid prepared in step (1). A gradient temperature increase method is used. First, the silk is soaked at 30-35°C for 1-2 hours. At this temperature, the silk fiber structure is relatively stable, which facilitates the initial penetration of the modification liquid. Then, the silk is soaked at 40-45°C for 1-2 hours. The increased temperature promotes fiber swelling, which facilitates the further penetration of the modification liquid into the fiber. Finally, the silk is soaked at 50-60°C for 1-3 hours. The higher temperature accelerates the reaction and allows the nanoparticles and the like to better combine with the silk. During this period, the silk is stirred every 30-60 minutes to allow the silk to fully absorb the modification liquid and improve the modification effect. S4: Post-treatment: The soaked silk is taken out and washed with deionized water until the washing liquid is neutral to remove excess modification liquid on the surface, and then placed in an oven at 60-80°C to dry to constant weight to obtain titanium dioxide-modified silk. Step S3: During the soaking, the bath ratio of silk to titanium dioxide modification liquid is 1:20-1:50, which can ensure that the silk has enough modification liquid for contact and absorption while avoiding waste of the modification liquid. Example 1

[0021] Disclosed is titanium dioxide-modified silk. The components of the titanium dioxide modification liquid are as follows: 5 parts by weight of nano-titanium dioxide, 1 part of sodium lauryl sulfate, 2 parts of glutaraldehyde, 0.5 parts of graphene quantum dots, 1 part of composite nanoparticles (0.75 parts of nano-zinc oxide and 0.25 parts of nano-silver), and 90 parts of deionized water. The average particle size of the nano-titanium dioxide is 10 nm. The preparation method comprises the following steps: S1: Preparation of titanium dioxide modified solution: Weigh the above components by mass, add nano-titanium dioxide, sodium lauryl sulfate, and composite nanoparticles to deionized water, stir evenly, and then ultrasonically disperse at 100 W power for 5 minutes, then at 300 W power for 10 minutes, then add glutaraldehyde and graphene quantum dots, and continue stirring for 10 minutes to obtain titanium dioxide modified solution; S2: Silk pretreatment: The silk was washed twice with deionized water and then dried in an oven at 60°C to constant weight; S3: Modification treatment: The pretreated silk was placed in a titanium dioxide modification solution with a bath ratio of 1:20. The solution was first soaked at 30°C for 1 hour, then at 40°C for 1 hour, and finally at 50°C for 1 hour using a gradient temperature increase method. The solution was stirred every 30 minutes. S4: Post-treatment: The soaked silk is taken out, washed with deionized water until the washing liquid is neutral, and then placed in an oven at 60° C. to dry to constant weight to obtain titanium dioxide-modified silk. Example 2

[0022] Disclosed is titanium dioxide-modified silk. The components of the titanium dioxide modification liquid are as follows by weight: 10 parts of nano-titanium dioxide, 3 parts of polyethylene glycol, 5 parts of citric acid, 2 parts of chitosan quaternary ammonium salt, 2.5 parts of composite nanoparticles (1.875 parts of nano-zinc oxide and 0.625 parts of nano-silver), and 76.5 parts of deionized water. The average particle size of the nano-titanium dioxide is 30 nm. The preparation method comprises the following steps: S1: Preparation of titanium dioxide modified solution: Weigh the above components by mass, add nano-titanium dioxide, polyethylene glycol, and composite nanoparticles into deionized water, stir evenly, and then ultrasonically disperse at 150 W power for 8 minutes, then at 350 W power for 15 minutes, then add citric acid and chitosan quaternary ammonium salt, and continue stirring for 15 minutes to obtain titanium dioxide modified solution; S2: Silk pretreatment: The silk was washed three times with deionized water and then dried in an oven at 70°C to constant weight; S3: Modification treatment: The pretreated silk was placed in a titanium dioxide modification solution with a bath ratio of 1:35. The solution was first soaked at 32°C for 1.5 h, then at 42°C for 1.5 h, and finally at 55°C for 2 h, with stirring every 45 min. S4: Post-treatment: The soaked silk is taken out, washed with deionized water until the washing liquid is neutral, and then placed in an oven at 70° C. to dry to constant weight to obtain titanium dioxide-modified silk. Example 3

[0023] Disclosed is titanium dioxide-modified silk. The components of the titanium dioxide modification liquid are as follows: 15 parts by weight of nano-titanium dioxide, 5 parts of a silane coupling agent, 8 parts of an epoxy resin, 3 parts of a chitosan quaternary ammonium salt, 4 parts of composite nanoparticles (3 parts of nano-zinc oxide and 1 part of nano-silver), and 68 parts of deionized water. The average particle size of the nano-titanium dioxide is 50 nm. The preparation method comprises the following steps: S1: Preparation of titanium dioxide modified solution: Weigh the above components by mass, add nano-titanium dioxide, silane coupling agent, and composite nanoparticles to deionized water, stir evenly, and then ultrasonically disperse at 200 W power for 10 minutes, then at 400 W power for 20 minutes, then add epoxy resin and chitosan quaternary ammonium salt, and continue stirring for 20 minutes to obtain titanium dioxide modified solution; S2: Silk pretreatment: The silk was washed three times with deionized water and then dried in an oven at 80°C to constant weight; S3: Modification treatment: The pretreated silk was placed in a titanium dioxide modification solution with a bath ratio of 1:50. A gradient temperature rise method was used, first soaking at 35°C for 2 hours, then at 45°C for 2 hours, and finally at 60°C for 3 hours, with stirring every 60 minutes. S4: Post-treatment: The soaked silk is taken out, washed with deionized water until the washing liquid is neutral, and then placed in an oven at 80° C. to dry to constant weight to obtain titanium dioxide-modified silk. The performance of the titanium dioxide-modified silk prepared in Examples 1-3 above was tested, and the results are shown in the following table:

[0024] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a..." does not exclude the presence of additional identical elements in the process, method, article, or device comprising the element.

[0025] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A titanium dioxide-modified silk, characterized in that: The invention is prepared by treating silk with a titanium dioxide modification liquid, wherein the titanium dioxide modification liquid comprises nano titanium dioxide, a dispersant, a cross-linking agent, a functional additive, composite nanoparticles and deionized water, wherein the weight proportions of the components are as follows: 5-15 parts of nano titanium dioxide, 1-5 parts of dispersant, 2-8 parts of cross-linking agent, 0.5-3 parts of functional additive, 1-4 parts of composite nanoparticles and 68-90 parts of deionized water; the functional additive is one of graphene quantum dots or chitosan quaternary ammonium salt; the composite nanoparticles are a composite of nano zinc oxide and nano silver, and the weight ratio of nano zinc oxide to nano silver is 3:

1.

2. The titanium dioxide-modified silk according to claim 1, characterized in that: The average particle size of the nano titanium dioxide is 10-50 nm.

3. The titanium dioxide-modified silk according to claim 1, characterized in that: The dispersant is at least one of sodium lauryl sulfate, polyethylene glycol or a silane coupling agent.

4. The titanium dioxide-modified silk according to claim 1, characterized in that: The cross-linking agent is at least one of glutaraldehyde, citric acid or epoxy resin.

5. The titanium dioxide-modified silk according to claim 1, characterized in that: When the cross-linking agent is glutaraldehyde, the pH value during the cross-linking reaction is controlled between 6 and 8 to promote the occurrence of the intermolecular cross-linking reaction and enhance the cross-linking effect.

6. The titanium dioxide-modified silk according to claim 1, characterized in that: When preparing the composite nanoparticles, nano zinc oxide is first dispersed in an aqueous solution containing a dispersant, dispersed for 15-20 minutes under an ultrasonic power of 200-300W, and then nano silver is added and ultrasonic dispersion is continued for 10-15 minutes to form a uniform composite nanoparticle dispersion liquid for the subsequent preparation of titanium dioxide modified liquid.

7. A method for preparing titanium dioxide-modified silk according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1: preparing a titanium dioxide modified liquid: weighing nano-titanium dioxide, a dispersant, a cross-linking agent, a functional additive, composite nanoparticles, and deionized water in parts by mass, adding the nano-titanium dioxide, dispersant, and composite nanoparticles to the deionized water, stirring evenly, and then ultrasonically dispersing the mixture at a power of 100-200 W for 5-10 minutes, then ultrasonically dispersing the mixture at a power of 300-400 W for 10-20 minutes, then adding the cross-linking agent and functional additive, and continuing stirring for 10-20 minutes to obtain a titanium dioxide modified liquid; S2: Silk pretreatment: The silk was washed 2-3 times with deionized water and then dried in an oven at 60-80°C to constant weight; S3: Modification treatment: Place the pretreated silk into the titanium dioxide modification solution prepared in step (1), and soak it at 30-35°C for 1-2 hours, then at 40-45°C for 1-2 hours, and finally at 50-60°C for 1-3 hours, stirring every 30-60 minutes. S4: Post-treatment: The soaked silk is taken out, washed with deionized water until the washing liquid is neutral, and then placed in an oven at 60-80°C to dry to constant weight to obtain titanium dioxide-modified silk.

8. The titanium dioxide-modified silk and the preparation method thereof according to claim 7, characterized in that: During the modification process, S3 applies low-frequency stirring of 50-60 Hz to the titanium dioxide modification liquid to further promote the penetration of various components in the modification liquid into the interior of the silk and improve the modification uniformity.

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