Preparation method of barrier antibacterial TPU composite film

Abstract

The application discloses a preparation method of a barrier antibacterial TPU composite film. Graphene oxide is prepared by using an improved hummers method, fluorinated graphene is prepared by using hydrofluoric acid as a fluorine source, the fluorinated graphene is used as a carbon source, and fluorinated graphene quantum dots are prepared under the action of an oxidant and an alkaline condition. Chitosan is dissolved in an acetic acid solution and reacts with the FGQDs under the action of dodecanol to form a barrier antibacterial agent CS / FGQDs. The TPU composite film produced by using the barrier antibacterial agent not only has a certain improvement in antibacterial performance, but also has improved barrier performance, and can generate great social and economic benefits.

Description

Technical Field

[0001] This invention belongs to the field of polymer composite materials, specifically relating to a method for preparing a barrier antibacterial agent and its application in the preparation of TPU composite films. Background Technology

[0002] Thermoplastic polyurethane elastomer (TPU) is a linear polymer obtained by block copolymerization of diisocyanate, small molecule polyol, and large molecule polyester or polyether polyol. It has been widely used in adhesives, coatings, composite materials, and biomedical materials. However, with the development of science and technology, higher requirements have been placed on the antibacterial and barrier properties of TPU composite films in some fields, such as film. Water vapor and gas molecules can easily permeate through TPU films, thus affecting their application in barrier applications. Due to the large number of ester and ether bonds in TPU films, coupled with certain temperature and humidity conditions, bacteria can easily adhere to and grow on their surface, forming a biofilm.

[0003] Carbon quantum dots (GQDs) possess numerous advantages, including excellent optical properties, good water solubility, low toxicity, environmental friendliness, wide availability of raw materials, low cost, and good biocompatibility. Depending on the carbon source, these methods can be broadly categorized into "top-down" and "bottom-up" synthesis methods. The latter often uses small organic molecules or oligomers as carbon sources, such as citric acid, glucose, polyethylene glycol, urea, and ionic liquids. Fluorinated graphene refers to a novel sheet-like nanomaterial formed when the carbon atoms in graphene are partially or completely fluorinated. Due to the low polarizability, strong electronegativity, and small van der Waals radius of fluorine atoms, the doping of fluorine and perfluorinated groups with graphene endows graphene with unique physicochemical properties and physiological activities, actively promoting the rapid development and expansion of the graphene family. GQDs possess excellent properties; heteroatom-doped GQDs can further modulate their band structure, resulting in unexpected characteristics. To date, GQDs have been rapidly developed for use in solar cells, photodetectors, imaging, and light-emitting diodes. To further expand the applications of GQDs, doping with heteroatoms is an effective material modification method. Through doping, tunable gaps in GQDs can be effectively designed, surface structures modified, and other heteroatoms added to achieve chemical functionalization.

[0004] Chitosan is a product of the natural polysaccharide chitin, which has undergone partial acetyl group removal. It possesses various physiological functions, including biodegradability, biocompatibility, non-toxicity, antibacterial properties, anticancer effects, lipid-lowering effects, and immune enhancement. It is widely used in food additives, textiles, agriculture, environmental protection, beauty and health products, cosmetics, antibacterial agents, and other daily chemical industries. Chitosan is insoluble in water, alkalis, and common organic solvents. However, due to the presence of -NH2 groups in its structural units, it readily reacts with acids to form salts. Therefore, chitosan can dissolve in many dilute inorganic acids or certain organic acids, such as hydrochloric acid, formic acid, acetic acid, lactic acid, malic acid, and ascorbic acid. The active adsorption centers of chitosan are its surface free amino groups, allowing it to adsorb and bind many inorganic acids, organic acids, acidic compounds, and even amphoteric compounds. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by providing a method for preparing a barrier antibacterial agent and its application. TPU composite films produced using this barrier antibacterial agent not only exhibit improved antibacterial properties but also enhanced barrier properties, potentially generating significant socio-economic benefits.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A method for preparing a barrier antibacterial agent involves preparing graphene oxide using a modified Hummers method, preparing fluorinated graphene using hydrofluoric acid as a fluorine source, preparing FGQDs using fluorinated graphene as a carbon source, and then grafting chitosan and FGQDs in an acetic acid solution under the action of dodecanol to form the barrier antibacterial agent CS / FGQDs.

[0008] The method for preparing the aforementioned barrier antibacterial agent includes the following steps:

[0009] (1) Graphene oxide (GO) was prepared using improved hummers;

[0010] (2) Disperse the GO prepared in step (1) in deionized water to prepare GO dispersion. Take the GO dispersion in a beaker, weigh out hydrofluoric acid, add it and stir for 0.5 h. Then transfer it to a polytetrafluoroethylene reactor and carry out hydrothermal reaction to obtain FGO.

[0011] (3) Disperse the FGO prepared in step (2) in deionized water, sonicate for 2 hours, add hydrogen peroxide and ammonia, reflux at 70°C for 6 hours, filter, dialyze, freeze dry to obtain FGQDs;

[0012] (4) Chitosan was dissolved in acetic acid solution and stirred for 6 hours to fully dissolve it. Dodecanol was added and stirred for 0.5 hours. FGQDs were added and stirred for 12 hours at room temperature. The mixture was then dried at 60°C to form a film to obtain the barrier antibacterial agent CS / FGQDs.

[0013] Furthermore, in step (2), the concentration of the GO dispersion is 2 mg / ml, the volume ratio of the GO dispersion to hydrofluoric acid is 40:2, the hydrothermal condition is 150℃, and the reaction time is 24h.

[0014] Furthermore, the ratio of FGO, hydrogen peroxide, and ammonia used in step (3) is 1 mg: 1 ml: 0.1 ml; the dialysis time is 3 days.

[0015] Furthermore, the acetic acid solution used in step (4) has a concentration of 1 wt%, the mass ratio of chitosan to dodecanol is 1:0.7, and the mass ratio of chitosan to FGQDs is 7:3.

[0016] Application of the aforementioned barrier antibacterial agent in the preparation of TPU composite film: The barrier antibacterial agent is mixed with TPU solution in a certain proportion, and a coating instrument is used to prepare a TPU composite film with good barrier antibacterial properties.

[0017] Furthermore, the amount of the barrier antibacterial agent accounts for 1-3% of the weight of the TPU composite film.

[0018] Furthermore, the TPU solution is prepared by dissolving a certain amount of TPU particles in DMF organic solvent at a certain temperature, with a ratio of 1g:5ml, a reaction temperature of 80℃, and a reaction time of 5h; the blending is prepared by mechanically stirring CS / FGQDs and TPU solution until no bubbles are generated; the coating instrument temperature is 80℃.

[0019] This invention prepares graphene oxide using a modified Hummers method, and fluorinated graphene using hydrofluoric acid as the fluorine source. Fluorinated graphene is then used as the carbon source to prepare fibrillated quantum dots (FGQDs). In an acetic acid solution, chitosan and FGQDs undergo a grafting reaction under the action of dodecyl alcohol to form the barrier antibacterial agent CS / FGQDs. The graphene oxide prepared using the modified Hummers method exhibits superior oxidation performance. Fluorinated graphene prepared using hydrofluoric acid as the fluorine source has more layers than graphene oxide, achieving a better barrier effect. Bottom-up synthesis methods for carbon quantum dots often use small organic molecules or oligomers as carbon sources; therefore, FGO is used as the carbon source to prepare FGQDs. As a crosslinking agent, chitosan is crosslinked into a three-dimensional network structure. The addition of dodecyl alcohol plasticizes the chitosan, transforming it into a hydrated polymorph. This polymorph is then added to the matrix as an additive, giving it barrier and antibacterial effects.

[0020] The beneficial effects of this invention are as follows:

[0021] This invention first oxidizes graphite to obtain GO using a modified Hummers method. Hydrofluoric acid is then used as the fluorine source to prepare FGO via a hydrothermal method. FGO is then used as the carbon source to prepare FGQDs. Chitosan is dissolved in acetic acid and reacted with FGQDs using dodecyl alcohol to prepare a CS / FGDQs barrier antibacterial agent. The modified Hummers method yields GO with superior oxidation compared to the traditional Hummers method, allowing for greater fluorination under the influence of the fluorine source, resulting in more effective fluorinated graphene with a higher number of exfoliated layers than graphene oxide, thus enhancing its barrier properties. Chitosan dissolves in acetic acid solution, and under the influence of dodecyl alcohol, it undergoes plasticization and changes its original crystal form, facilitating grafting reactions with FGQDs. Chitosan possesses good biocompatibility, facilitating processing. Its cross-linked structure forms a dense spatial structure, maximizing its barrier and antibacterial properties.

[0022] Compared with pure TPU film, the TPU composite film prepared by mixing the barrier antibacterial agent obtained in this invention with TPU solution under magnetic stirring and then using a coating instrument has a more uniform film formation and more uniform additive dispersion, thus exhibiting a more efficient barrier antibacterial effect. Attached Figure Description

[0023] Figure 1 The Fourier transform infrared spectra of GO and FGO prepared in Example 5 are shown below. Comparing the infrared spectra of GO and FGO, it can be observed that GO is reduced by hydrofluoric acid under hydrothermal conditions, and the reduction occurs at 1170 cm⁻¹. -1 With 1135cm -1 The appearance of new absorption peaks indicates the covalent CF and half-ionic CF bonds, and the presence of these two peaks demonstrates the successful preparation of fluorinated graphene.

[0024] Figure 2 The image shows a SEM image of GO prepared in Example 5; the GO prepared by modifying hummers has a sheet-like structure and is relatively thin.

[0025] Figure 3 The image shows a SEM image of FGO prepared in Example 5. The microscopic surface of FGO is rougher than that of GO. Although both are lamellar structures, FGO is thicker.

[0026] Figure 4 The image shows a TEM image of the FGQDs prepared in Example 5. Small dots can be observed at around 10 nm, which proves that the FGQDs were successfully prepared.

[0027] Figure 5 The image shows a SEM image of the CS surface; the surface is relatively rough and there is no other material loaded on the surface.

[0028] Figure 6 This is a SEM image of the CS / FGQDs prepared in Example 5; the surface is relatively smooth, with fine particles adhering to the surface, compared to... Figure 5 Its surface is smoother because there is a hydrogen bond between FGQDs and CS, which makes the prepared film surface smoother. Detailed Implementation

[0029] The preparation of a barrier antibacterial TPU composite material includes the following steps:

[0030] (1) Graphene oxide (GO) was prepared by the modified Hummers method: under ice bath conditions, graphite was dispersed in a mixture of concentrated sulfuric acid and phosphoric acid (4:1, v / v), and NaNO3 was added. After stirring for 1 h, potassium permanganate was added (added in 2-3 h). After standing overnight, the mixture was transferred to 45°C and reacted for 4 h. The temperature was then raised to 85°C. At the same time as raising the temperature, 40 ml of deionized water was added per gram of graphite. After the temperature reached 85°C, hydrogen peroxide was added until no bubbles were generated. Concentrated hydrochloric acid was added to wash away the metal ions. The mixture was allowed to stand for 8-12 h. After centrifugation and washing until the washing liquid was neutral, the product was freeze-dried to obtain GO.

[0031] (2) Disperse the GO prepared in step (1) in deionized water to prepare GO dispersion. Take the GO dispersion in a beaker, weigh out hydrofluoric acid, add it and stir for 0.5 h. Then transfer it to a polytetrafluoroethylene reactor and carry out hydrothermal reaction to obtain FGO.

[0032] (3) Disperse the FGO prepared in step (2) in deionized water, sonicate for 2 hours, add hydrogen peroxide and ammonia, reflux at 70°C for 6 hours, filter, dialyze, freeze dry to obtain FGQDs;

[0033] (4) Dissolve chitosan in acetic acid solution, stir for 6 hours to fully dissolve it, add dodecanol and stir for 0.5 hours, add FGQDs, stir for 12 hours at room temperature, and dry at 60°C to form a film to obtain the barrier antibacterial agent CS / FGQDs.

[0034] (5) At room temperature, the CS / FGQDs obtained in step (4) are mixed with TPU solution in a certain proportion, and a coating instrument is used to prepare a TPU composite film with good barrier antibacterial properties.

[0035] In step (1), the mass ratio of graphite to potassium permanganate is 1:4, and the concentrated hydrochloric acid used is 5 times the mass of graphite.

[0036] The volume ratio of GO dispersion to hydrofluoric acid used in step (2) is 40:2.

[0037] The ratio of FGO, hydrogen peroxide and ammonia used in step (3) is 1mg:1ml:0.1ml.

[0038] The mass ratio of chitosan to dodecanol used in step (4) is 1:0.7, and the mass ratio of chitosan to FGQDs is 7:3;

[0039] The amount of the barrier antibacterial agent used in step (5) accounts for 1-3% of the weight of the TPU composite film; the TPU solution is a certain amount of TPU particles dissolved in DMF organic solution at a certain temperature, with a ratio of 1g:5ml, a reaction temperature of 80℃, and a reaction time of 5h; the blending is to mechanically stir CS / FGQDs and TPU solution until no bubbles are generated; the coating instrument temperature is 80℃.

[0040] To make the content of this invention easier to understand, the technical solution of this invention will be further described below with reference to specific embodiments, but this invention is not limited thereto.

[0041] Example 1

[0042] A method for preparing a barrier antibacterial TPU composite film includes the following steps:

[0043] (1) Take 1g of graphite and add it to a mixture of 32ml of 98w% concentrated sulfuric acid and 8ml of 85wt% phosphoric acid. Then add 1g of NaNO3 and place it in an ice bath. Stir for 12h and then add 4g of potassium permanganate (0.4g every 10 minutes, added over 2h). Transfer it to a water bath at 45℃ and react for 4h. Then raise the temperature to 80℃ and add 160ml of deionized water while raising the temperature. When the temperature reaches 85℃, add 30wt% hydrogen peroxide until no more bubbles are generated. Then add 6ml of 98wt% concentrated hydrochloric acid to wash away the metal ions and let it stand for 12h. Centrifuge and wash until the washing liquid is neutral. Then freeze dry the product to obtain GO.

[0044] (2) Weigh 80mg of GO from step (1) and disperse it in deionized water to prepare a GO dispersion of 2mg / ml. Use a pipette to extract 2ml of 99wt% hydrofluoric acid and add it to the dispersion. Stir for 0.5h and then transfer it to a polytetrafluoroethylene reactor. The reaction temperature is 150℃ and the reaction time is 24h to carry out the hydrothermal reaction to obtain FGO, which is then freeze-dried for later use.

[0045] (3) Disperse 60 mg of FGO obtained in step (2) in 60 ml of deionized water, sonicate for 2 h, add 60 ml of 30 wt% hydrogen peroxide and 0.4 ml of 20 wt% ammonia, reflux at 70 °C for 6 h, filter, dialyze, freeze dry to obtain FGQDs;

[0046] (4) Weigh 0.7g of chitosan and dissolve it in 100ml of 1wt% acetic acid solution. Stir for 6h to fully dissolve it, add 0.7g of dodecanol and stir for 0.5h, add 0.3g of FGQDs, stir for 12h at room temperature, and dry at 60℃ to form a film to obtain CS / FGQDs.

[0047] (5) After 14.85g of TPU particles were placed in an 80℃ drying oven to swell for a period of time, they were dissolved in 75ml of DMF at 80℃. After stirring for 5h, they were fully dissolved. 0.15g of CS / FGQDs from step (4) was added to the mixture (1% of the total amount). After stirring for 3h, they were fully dissolved and some of the organic solvent was evaporated. Then, the air inside was extracted using a vacuum filter. The film was coated on a coating machine at 80℃ to obtain a CS / FGQDs / TPU composite film, which was then cut into 50cm pieces. 2 The discs were tested.

[0048] Example 2

[0049] A method for preparing a barrier antibacterial TPU composite film includes the following steps:

[0050] (1) Take 1g of graphite and add it to a mixture of 32ml of 98w% concentrated sulfuric acid and 8ml of 85wt% phosphoric acid. Then add 1g of NaNO3 and place it in an ice bath. Stir for 12h and then add 4g of potassium permanganate (0.4g every 10 minutes, added over 2h). Transfer it to a water bath at 45℃ and react for 4h. Then raise the temperature to 80℃ and add 160ml of deionized water while raising the temperature. When the temperature reaches 85℃, add 30wt% hydrogen peroxide until no more bubbles are generated. Then add 6ml of 98wt% concentrated hydrochloric acid to wash away the metal ions and let it stand for 12h. Centrifuge and wash until the washing liquid is neutral. Then freeze dry the product to obtain GO.

[0051] (2) Weigh 80mg of GO from step (1) and disperse it in deionized water to prepare a GO dispersion of 2mg / ml. Use a pipette to extract 2ml of 99wt% hydrofluoric acid and add it to the dispersion. Stir for 0.5h and then transfer it to a polytetrafluoroethylene reactor. The reaction temperature is 150℃ and the reaction time is 24h to carry out the hydrothermal reaction to obtain FGO, which is then freeze-dried for later use.

[0052] (3) Disperse 60 mg of FGO obtained in step (2) in 60 ml of deionized water, sonicate for 2 h, add 60 ml of 30 wt% hydrogen peroxide and 0.4 ml of 20 wt% ammonia, reflux at 70 °C for 6 h, filter, dialyze, freeze dry to obtain FGQDs;

[0053] (4) Weigh 0.7g of chitosan and dissolve it in 100ml of 1wt% acetic acid solution. Stir for 6h to fully dissolve it, add 0.7g of dodecanol and stir for 0.5h, add 0.3g of FGQDs, stir for 12h at room temperature, and dry at 60℃ to form a film to obtain CS / FGQDs.

[0054] (5) After 14.775g of TPU particles were placed in an 80℃ drying oven to swell for a period of time, they were dissolved in 75ml of DMF at 80℃. After stirring for 5 hours, they were fully dissolved. 0.225g of CS / FGQDs from step (4) was added to the mixture (1.5% of the total amount). After stirring for 3 hours, it was fully dissolved and some of the organic solvent was evaporated. Then, the air inside was extracted using a vacuum filter. The film was coated on a coating machine at 80℃ to obtain a CS / FGQDs / TPU composite film, which was then cut into 50cm pieces. 2 The discs were tested.

[0055] Example 3

[0056] A method for preparing a barrier antibacterial TPU composite film includes the following steps:

[0057] (1) Take 1g of graphite and add it to a mixture of 32ml of 98w% concentrated sulfuric acid and 8ml of 85wt% phosphoric acid. Then add 1g of NaNO3 and place it in an ice bath. Stir for 12h and then add 4g of potassium permanganate (0.4g every 10 minutes, added over 2h). Transfer it to a water bath at 45℃ and react for 4h. Then raise the temperature to 80℃ and add 160ml of deionized water while raising the temperature. When the temperature reaches 85℃, add 30wt% hydrogen peroxide until no more bubbles are generated. Then add 6ml of 98wt% concentrated hydrochloric acid to wash away the metal ions and let it stand for 12h. Centrifuge and wash until the washing liquid is neutral. Then freeze dry the product to obtain GO.

[0058] (2) Weigh 80mg of GO from step (1) and disperse it in deionized water to prepare a GO dispersion of 2mg / ml. Use a pipette to extract 2ml of 99wt% hydrofluoric acid and add it to the dispersion. Stir for 0.5h and then transfer it to a polytetrafluoroethylene reactor. The reaction temperature is 150℃ and the reaction time is 24h to carry out the hydrothermal reaction to obtain FGO, which is then freeze-dried for later use.

[0059] (3) Disperse 60 mg of FGO obtained in step (2) in 60 ml of deionized water, sonicate for 2 h, add 60 ml of 30 wt% hydrogen peroxide and 0.4 ml of 20 wt% ammonia, reflux at 70 °C for 6 h, filter, dialyze, freeze dry to obtain FGQDs;

[0060] (4) Weigh 0.7g of chitosan and dissolve it in 100ml of 1wt% acetic acid solution. Stir for 6h to fully dissolve it, add 0.7g of dodecanol and stir for 0.5h, add 0.3g of FGQDs, stir for 12h at room temperature, and dry at 60℃ to form a film to obtain CS / FGQDs.

[0061] (5) After 14.7g of TPU particles were placed in an 80℃ drying oven to swell for a period of time, they were dissolved in 75ml of DMF at 80℃. After stirring for 5 hours, they were fully dissolved. 0.3g of CS / FGQDs from step (4) was added to the mixture (2% of the total amount). After stirring for 3 hours, it was fully dissolved and some of the organic solvent was evaporated. Then, the air inside was extracted using a vacuum filter. The film was coated on a coating machine at 80℃ to obtain a CS / FGQDs / TPU composite film, which was then cut into 50cm pieces. 2 The discs were tested.

[0062] Example 4

[0063] A method for preparing a barrier antibacterial TPU composite film includes the following steps:

[0064] (1) Take 1g of graphite and add it to a mixture of 32ml of 98w% concentrated sulfuric acid and 8ml of 85wt% phosphoric acid. Then add 1g of NaNO3 and place it in an ice bath. Stir for 12h and then add 4g of potassium permanganate (0.4g every 10 minutes, added over 2h). Transfer it to a water bath at 45℃ and react for 4h. Then raise the temperature to 80℃ and add 160ml of deionized water while raising the temperature. When the temperature reaches 85℃, add 30wt% hydrogen peroxide until no more bubbles are generated. Then add 6ml of 98wt% concentrated hydrochloric acid to wash away the metal ions and let it stand for 12h. Centrifuge and wash until the washing liquid is neutral. Then freeze dry the product to obtain GO.

[0065] (2) Weigh 80mg of GO from step (1) and disperse it in deionized water to prepare a GO dispersion of 2mg / ml. Use a pipette to extract 2ml of 99wt% hydrofluoric acid and add it to the dispersion. Stir for 0.5h and then transfer it to a polytetrafluoroethylene reactor. The reaction temperature is 150℃ and the reaction time is 24h to carry out the hydrothermal reaction to obtain FGO, which is then freeze-dried for later use.

[0066] (3) Disperse 60 mg of FGO obtained in step (2) in 60 ml of deionized water, sonicate for 2 h, add 60 ml of 30 wt% hydrogen peroxide and 0.4 ml of 20 wt% ammonia, reflux at 70 °C for 6 h, filter, dialyze, freeze dry to obtain FGQDs;

[0067] (4) Weigh 0.7g of chitosan and dissolve it in 100ml of 1wt% acetic acid solution. Stir for 6h to fully dissolve it, add 0.7g of dodecanol and stir for 0.5h, add 0.3g of FGQDs, stir for 12h at room temperature, and dry at 60℃ to form a film to obtain CS / FGQDs.

[0068] (5) After 14.625g of TPU particles were placed in an 80℃ drying oven to swell for a period of time, they were dissolved in 75ml of DMF at 80℃. After stirring for 5 hours, they were fully dissolved. 0.375g of CS / FGQDs from step (4) was added to the mixture (the amount added accounted for 2.5% of the total amount). After stirring for 3 hours, they were fully dissolved and some of the organic solvent was evaporated. Then, the air inside was extracted on a vacuum filter. The film was coated on a coating machine at 80℃ to obtain a CS / FGQDs / TPU composite film, which was then cut into 50cm pieces. 2 The discs were tested.

[0069] Example 5

[0070] A method for preparing a barrier antibacterial TPU composite film includes the following steps:

[0071] (1) Take 1g of graphite and add it to a mixture of 32ml of 98w% concentrated sulfuric acid and 8ml of 85wt% phosphoric acid. Then add 1g of NaNO3 and place it in an ice bath. Stir for 12h and then add 4g of potassium permanganate (0.4g every 10 minutes, added over 2h). Transfer it to a water bath at 45℃ and react for 4h. Then raise the temperature to 80℃ and add 160ml of deionized water while raising the temperature. When the temperature reaches 85℃, add 30wt% hydrogen peroxide until no more bubbles are generated. Then add 6ml of 98wt% concentrated hydrochloric acid to wash away the metal ions and let it stand for 12h. Centrifuge and wash until the washing liquid is neutral. Then freeze dry the product to obtain GO.

[0072] (2) Weigh 80mg of GO from step (1) and disperse it in deionized water to prepare a GO dispersion of 2mg / ml. Use a pipette to extract 2ml of 99wt% hydrofluoric acid and add it to the dispersion. Stir for 0.5h and then transfer it to a polytetrafluoroethylene reactor. The reaction temperature is 150℃ and the reaction time is 24h to carry out the hydrothermal reaction to obtain FGO, which is then freeze-dried for later use.

[0073] (3) Disperse 60 mg of FGO obtained in step (2) in 60 ml of deionized water, sonicate for 2 h, add 60 ml of 30 wt% hydrogen peroxide and 0.4 ml of 20 wt% ammonia, reflux at 70 °C for 6 h, filter, dialyze, freeze dry to obtain FGQDs;

[0074] (4) Weigh 0.7g of chitosan and dissolve it in 100ml of 1wt% acetic acid solution. Stir for 6h to fully dissolve it, add 0.7g of dodecanol and stir for 0.5h, add 0.3g of FGQDs, stir for 12h at room temperature, and dry at 60℃ to form a film to obtain CS / FGQDs.

[0075] (5) After 14.55g of TPU particles were placed in an 80℃ drying oven to swell for a period of time, they were dissolved in 75ml of DMF at 80℃. After stirring for 5 hours, they were fully dissolved. 0.45g of CS / FGQDs from step (4) was added to the mixture (3% of the total amount). After stirring for 3 hours, they were fully dissolved and some of the organic solvent was evaporated. Then, the air inside was extracted using a vacuum filter. The film was coated on a coating machine at 80℃ to obtain a CS / FGQDs / TPU composite film, which was then cut into 50cm pieces. 2 The discs were tested.

[0076] Comparative Example 1 (Pure TPU)

[0077] 15g of TPU granules were placed in an 80℃ drying oven to swell for a period of time, then dissolved in 75ml of DMF at 80℃. After stirring for 5 hours, the granules were fully dissolved and some of the organic solvent was evaporated. The air inside was then removed using a vacuum filter. A coating film was then formed on a coating machine at 80℃ to obtain a CS / FGQDs / TPU composite film, which was then cut into 50cm pieces. 2 The discs were tested.

[0078] Comparative Example 2 (with only GO added)

[0079] (1) Take 1g of graphite and add it to a mixture of 32ml of 98w% concentrated sulfuric acid and 8ml of 85wt% phosphoric acid. Then add 1g of NaNO3 and place it in an ice bath. Stir for 12h and then add 4g of potassium permanganate (0.4g every 10 minutes, added over 2h). Transfer it to a water bath at 45℃ and react for 4h. Then raise the temperature to 80℃ and add 160ml of deionized water while raising the temperature. When the temperature reaches 85℃, add 30wt% hydrogen peroxide until no more bubbles are generated. Then add 6ml of 98wt% concentrated hydrochloric acid to wash away the metal ions and let it stand for 12h. Centrifuge and wash until the washing liquid is neutral. Then freeze dry the product to obtain GO.

[0080] (2) After 14.55g of TPU particles were placed in an 80℃ drying oven to swell for a period of time, they were dissolved in 75ml of DMF at 80℃. After stirring for 5 hours, they were fully dissolved. 0.45g of GO from step (1) was added to the mixture (3% of the total amount). After stirring for 3 hours, it was fully dissolved and some of the organic solvent was evaporated. Then, the air inside was extracted using a vacuum filter. The film was coated on a coating machine at 80℃ to obtain a GO / TPU composite film, which was then cut into 50cm pieces. 2 The discs were tested.

[0081] Comparative Example 3 (CS only)

[0082] 14.55g of TPU granules were placed in an 80℃ drying oven to swell for a period of time, then dissolved in 75ml of DMF at 80℃. After stirring for 5 hours, the mixture was fully dissolved. 0.45g of CS (3% of the total amount) was added to the mixture, and after stirring for 3 hours, it was fully dissolved and some of the organic solvent evaporated. The air inside was then removed using a vacuum filter. A coating film was then formed on a coating machine at 80℃ to obtain a CS / TPU composite film, which was cut into 50cm pieces. 2 The discs were tested.

[0083] Comparison Example 4 (FGO only)

[0084] (1) Take 1g of graphite and add it to a mixture of 32ml of 98w% concentrated sulfuric acid and 8ml of 85wt% phosphoric acid. Then add 1g of NaNO3 and place it in an ice bath. Stir for 12h and then add 4g of potassium permanganate (0.4g every 10 minutes, added over 2h). Transfer it to a water bath at 45℃ and react for 4h. Then raise the temperature to 80℃ and add 160ml of deionized water while raising the temperature. When the temperature reaches 85℃, add 30wt% hydrogen peroxide until no more bubbles are generated. Then add 6ml of 98wt% concentrated hydrochloric acid to wash away the metal ions and let it stand for 12h. Centrifuge and wash until the washing liquid is neutral. Then freeze dry the product to obtain GO.

[0085] (2) Weigh 80mg of GO from step (1) and disperse it in deionized water to prepare a GO dispersion of 2mg / ml. Use a pipette to extract 2ml of 99wt% hydrofluoric acid and add it to the dispersion. Stir for 0.5h and then transfer it to a polytetrafluoroethylene reactor. The reaction temperature is 150℃ and the reaction time is 24h to carry out the hydrothermal reaction to obtain FGO, which is then freeze-dried for later use.

[0086] (3) After 14.55g of TPU particles were placed in an 80℃ drying oven to swell for a period of time, they were dissolved in 75ml of DMF at 80℃. After stirring for 5 hours, they were fully dissolved. 0.45g of FGO from step (2) was added to the mixture (3% of the total amount). After stirring for 3 hours, it was fully dissolved and some of the organic solvent was evaporated. Then, the air inside was extracted using a vacuum filter. The film was coated on a coating machine at 80℃ to obtain an FGO / TPU composite film, which was then cut into 50cm pieces. 2 The discs were tested.

[0087] Comparative Example 5 (FGQDs only)

[0088] (1) Take 1g of graphite and add it to a mixture of 32ml of 98w% concentrated sulfuric acid and 8ml of 85wt% phosphoric acid. Then add 1g of NaNO3 and place it in an ice bath. Stir for 12h and then add 4g of potassium permanganate (0.4g every 10 minutes, added over 2h). Transfer it to a water bath at 45℃ and react for 4h. Then raise the temperature to 80℃ and add 160ml of deionized water while raising the temperature. When the temperature reaches 85℃, add 30wt% hydrogen peroxide until no more bubbles are generated. Then add 6ml of 98wt% concentrated hydrochloric acid to wash away the metal ions and let it stand for 12h. Centrifuge and wash until the washing liquid is neutral. Then freeze dry the product to obtain GO.

[0089] (2) Weigh 80mg of GO from step (1) and disperse it in deionized water to prepare a GO dispersion of 2mg / ml. Use a pipette to extract 2ml of 99wt% hydrofluoric acid and add it to the dispersion. Stir for 0.5h and then transfer it to a polytetrafluoroethylene reactor. The reaction temperature is 150℃ and the reaction time is 24h to carry out the hydrothermal reaction to obtain FGO, which is then freeze-dried for later use.

[0090] (3) Disperse 60 mg of FGO obtained in step (2) in 60 ml of deionized water, sonicate for 2 h, add 60 ml of 30 wt% hydrogen peroxide and 0.4 ml of 20 wt% ammonia, reflux at 70 °C for 6 h, filter, dialyze, freeze dry to obtain FGQDs;

[0091] (4) After 14.55g of TPU particles were placed in an 80℃ drying oven to swell for a period of time, they were dissolved in 75ml of DMF at 80℃. After stirring for 5h, they were fully dissolved. 0.45g of FGQDs from step (3) was added to the mixture (3% of the total amount). After stirring for 3h, they were fully dissolved and some of the organic solvent was evaporated. Then, the air inside was extracted on a vacuum filter. The film was coated on a coating machine at 80℃ to obtain an FGQDs / TPU composite film, which was then cut into 50cm2 discs for testing.

[0092] Comparative Example 6

[0093] A method for preparing a barrier antibacterial TPU composite film includes the following steps:

[0094] (1) Take 1g of graphite and add it to a mixture of 32ml of 98w% concentrated sulfuric acid and 8ml of 85wt% phosphoric acid. Then add 1g of NaNO3 and place it in an ice bath. Stir for 12h and then add 4g of potassium permanganate (0.4g every 10 minutes, added over 2h). Transfer it to a water bath at 45℃ and react for 4h. Then raise the temperature to 80℃ and add 160ml of deionized water while raising the temperature. When the temperature reaches 85℃, add 30wt% hydrogen peroxide until no more bubbles are generated. Then add 6ml of 98wt% concentrated hydrochloric acid to wash away the metal ions and let it stand for 12h. Centrifuge and wash until the washing liquid is neutral. Then freeze dry the product to obtain GO.

[0095] (2) Weigh 80mg of GO from step (1) and disperse it in deionized water to prepare a GO dispersion of 2mg / ml. Use a pipette to extract 2ml of 99wt% hydrofluoric acid and add it to the dispersion. Stir for 0.5h and then transfer it to a polytetrafluoroethylene reactor. The reaction temperature is 150℃ and the reaction time is 24h to carry out the hydrothermal reaction to obtain FGO, which is then freeze-dried for later use.

[0096] (3) Disperse 60 mg of FGO obtained in step (2) in 60 ml of deionized water, sonicate for 2 h, add 60 ml of 30 wt% hydrogen peroxide and 0.4 ml of 20 wt% ammonia, reflux at 70 °C for 6 h, filter, dialyze, freeze dry to obtain FGQDs;

[0097] (4) Weigh 0.7g of chitosan and dissolve it in 100ml of 1wt% acetic acid solution. Stir for 6h to fully dissolve it, add 0.7g of dodecanol and stir for 0.5h, add 0.3g of FGQDs, stir for 12h at room temperature, and dry at 60℃ to form a film to obtain CS / FGQDs.

[0098] (5) After 14.40g of TPU particles were placed in an 80℃ drying oven to swell for a period of time, they were dissolved in 75ml of DMF at 80℃. After stirring for 5 hours, they were fully dissolved. 0.6g of CS / FGQDs from step (4) was added to the mixture (4% of the total amount). After stirring for 3 hours, they were fully dissolved and some of the organic solvent was evaporated. Then, the air inside was extracted using a vacuum filter. The film was coated on a coating machine at 80℃ to obtain a CS / FGQDs / TPU composite film, which was then cut into 50cm pieces. 2 The discs were tested.

[0099] The TPU test strips obtained from the examples and comparative examples were subjected to performance tests, and the results are shown in Table 1.

[0100] The testing standards are based on the following national standards;

[0101] Tensile strength and elongation at break:

[0102] According to GB / T 1040.3-2006, the tensile properties and elongation at break of composite films were determined. Standard film strips were prepared by melt casting, and the tensile speed was set to 500 mm / min. The TPU samples were tested repeatedly 5 times, and the average value was taken to reduce experimental error.

[0103] The formula for tensile strength is as shown in equation (1-1):

[0104] Formula (1-1)

[0105] In the formula: σ t 1 represents tensile strength in MPa; P represents maximum load in N; b represents specimen width in mm; d represents specimen thickness in mm.

[0106] The formula for elongation at break is as shown in equation (1-2):

[0107] Formula (1-2)

[0108] In the formula: δ represents the elongation at break; L represents the gauge length at break of the specimen, in mm; L0 represents the original gauge length of the specimen, in mm.

[0109] Oxygen permeability:

[0110] The oxygen permeability of the TPU film was tested according to GB / T 31354-2014, "Test Method for Oxygen Permeability of Packaging and Containers". The film was cut into 50 cm pieces. 2 The films were tested three times for each group of thin film materials, and the average value was taken. The lower the oxygen permeability, the better the barrier performance of the film, and the more difficult it is for gas to pass through the film.

[0111] Antibacterial test:

[0112] The antibacterial properties of TPU membrane materials were tested according to the national standard GB / T37206-2018, "Test Method for Antibacterial Properties of Organic Separation Membranes".

[0113] Table 1 Performance Test Results

[0114]

[0115] As shown in Table 1, the tensile strength of the composite membrane was significantly improved with the addition of antibacterial barrier agents CS / FGQDs in Examples 1-5. Combined with the data from Comparative Examples 1-5, the addition of GO, CS, FGO, and FGQDs all contribute to improving the tensile strength of the composite material. The tensile strength of the composite membrane increased after the addition of CS / FGQDs because FGQDs, through the plasticizing effect of dodecanol, crosslinked multiple layers of CS into sheets, forming a dense two-dimensional structure. Simultaneously, the elongation at break of the composite membrane also increased, due to the addition of fillers altering the original structure of the TPU membrane. Furthermore, the oxygen permeability of the composite membrane decreased continuously with the increase of the amount of antibacterial barrier agents CS / FGQDs, achieving a good barrier effect, and its antibacterial rate also increased.

[0116] Comparing the data from Example 5 and Comparative Example 5, the composite membrane with added barrier antibacterial agent CS / FGQDs exhibits better barrier and antibacterial properties compared to the addition of FGQDs. This is because FGQDs act as a crosslinker, tightly binding CS into a dense two-dimensional structure, thus reducing its oxygen permeability. CS also possesses excellent antibacterial effects, and its addition can improve the antibacterial performance of the composite membrane.

[0117] Comparing the data of Example 5 and Comparative Example 6, it can be seen that when CS / FGQDs is added at 4%, the excessive addition damages the original structure of the membrane material, resulting in a decrease in mechanical properties. Therefore, the optimal addition ratio of CS / FGQDs is 3%.

[0118] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made within the scope of the claims of the present invention should be included in the scope of the present invention.

Claims

1. A method for preparing a barrier antibacterial agent, characterized in that: Includes the following steps: (1) Graphene oxide (GO) was prepared using improved hummers; (2) Disperse the GO prepared in step (1) in deionized water to prepare GO dispersion. Take the GO dispersion in a beaker, weigh out hydrofluoric acid, add it and stir for 0.5 h. Then transfer it to a polytetrafluoroethylene reactor and carry out hydrothermal reaction to obtain FGO. (3) Disperse the FGO prepared in step (2) in deionized water, sonicate for 2 hours, add hydrogen peroxide and ammonia, reflux at 70°C for 6 hours, filter, dialyze, freeze dry to obtain FGQDs; (4) Chitosan was dissolved in acetic acid solution and stirred for 6 hours to fully dissolve it. Dodecanol was added and stirred for 0.5 hours. FGQDs were added and stirred at room temperature for 12 hours. The mixture was then dried at 60°C to obtain the barrier antibacterial agent CS / FGQDs. In step (2), the concentration of GO dispersion is 2 mg / ml, the volume ratio of GO dispersion to hydrofluoric acid is 40:2, the hydrothermal condition is 150℃, and the reaction time is 24h. The ratio of FGO, hydrogen peroxide, and ammonia used in step (3) is 1 mg: 1 ml: 0.1 ml; the dialysis time is 3 days. The acetic acid solution used in step (4) has a concentration of 1 wt%, the mass ratio of chitosan to dodecanol is 1:0.7, and the mass ratio of chitosan to FGQDs is 7:

3.

2. A barrier antibacterial agent prepared by the method described in claim 1.

3. The application of the barrier antibacterial agent as described in claim 2 in the preparation of TPU composite films, characterized in that: A TPU composite film with barrier and antibacterial properties was prepared by mixing a barrier antibacterial agent with a TPU solution in a certain proportion and using a coating instrument.

4. The application of the barrier antibacterial agent according to claim 3 in the preparation of TPU composite films, characterized in that: The amount of the barrier antibacterial agent is 1-3% of the weight of the TPU composite film.

5. The application of the barrier antibacterial agent according to claim 3 in the preparation of TPU composite films, characterized in that: The TPU solution is prepared by dissolving TPU particles in DMF at a certain temperature, with a ratio of 1g:5ml, a reaction temperature of 80℃, and a reaction time of 5h; the blending is prepared by mechanically stirring CS / FGQDs and the TPU solution until no bubbles are generated; the temperature of the coating apparatus is 80℃.

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