Multifunctional polymer foam with efficient antibacterial and photoinduced heating characteristics and preparation method

Abstract

The invention discloses multifunctional polymer foam with efficient antibacterial and photoinduced heating characteristics and a preparation method, and belongs to the technical field of multifunctional polymer foam materials. The preparation method comprises the following steps: (1) immersing polymer foam into a graphene suspension, and carrying out ultrasonic treatment to prepare graphene polymer foam; (2) potassium persulfate, potassium hydroxide and a silver nitrate solution are heated and stirred for a reaction, precipitates are collected and dispersed in a mixed solution of a surfactant and carboxylated chitosan, and a high / low-valence silver hybrid oxide coating is prepared; and (3) spraying the high / low-valence silver hybrid oxide coating on the surface of the graphene polymer foam, and drying to obtain the graphene polymer foam. The preparation method is simple, the preparation efficiency is high, the prepared multifunctional polymer foam has excellent photo-thermal conversion effect and efficient antibacterial property, and has excellent illumination-cooling cycle stability, and guarantee is provided for application of the multifunctional polymer foam in the aspects of photo-thermal and synergistic antibacterial functions.

Description

Technical Field

[0001] The present invention relates to the technical field of multifunctional polymer foam materials, and particularly relates to a multifunctional polymer foam with high-efficiency antibacterial and photoinduced heating characteristics and a preparation method thereof. Background Art

[0002] In recent years, the problem of the atmospheric environment has become increasingly prominent. Moreover, a large number of pathogenic bacteria exist in the air of some human activity environments, which poses a great harm to the health of the human respiratory system. Therefore, it is of great practical significance to prepare air purification and filtration materials with antibacterial functions. Traditional filter materials are generally composed of polymer fibers, and most of them can only intercept and electrostatically adsorb suspended particles in the air, and it is difficult to remove viruses and bacteria in the air.

[0003] Most of the antibacterial porous polymer filter purification materials prepared in the prior art achieve the antibacterial effect by adding antibacterial fillers to fiber non-woven fabrics. This method is difficult to fully exert the performance of the antibacterial fillers themselves. In addition, some existing antibacterial porous polymer materials only have a single antibacterial function, such as only photothermal response, and the integration of the two functions is very few. Existing patents such as the material prepared by impregnating a substrate of acrylic and spandex interwoven fabric in an aqueous solution of carbon nanotubes and an aqueous solution of silver nitrate disclosed in 201911280436.X has both photothermal effect and antibacterial property. However, the material obtained by this scheme has a slow photothermal conversion speed and a low elevated temperature (the temperature rises from 18.6 °C to 35.8 °C after 120 seconds of illumination), which cannot meet the requirements of high photothermal conversion efficiency for photothermal applications such as solar evaporation, photothermal catalysis, and energy production. Therefore, there is an urgent need to develop a flexible conductive composite material with high-efficiency antibacterial property and excellent photothermal conversion effect to meet the multifunctional application requirements of sterilizing air purification and filtration. Graphene is a two-dimensional carbon nanosheet with a large specific surface area and broad-spectrum sunlight photothermal conversion ability. At the same time, it also has certain antibacterial ability. However, there is currently no technology for directly modifying the surface of polymer foam with graphene with broad-spectrum sunlight absorption ability and nano high / low-valent silver hybrid oxide particles with high-efficiency antibacterial property to obtain multifunctional polymer foam materials and their applications in air purification and sterilization. Summary of the Invention

[0004] In order to solve the above technical problems, the purpose of the present invention is to provide a multifunctional polymer foam with high-efficiency antibacterial and photoinduced heating characteristics and a preparation method thereof, so as to solve the problems of slow photothermal conversion speed, low elevated temperature, low photothermal conversion efficiency, or only having a single antibacterial performance / photothermal response performance of the existing antibacterial porous polymer materials with photothermal effect.

[0005] The technical solution of the present invention to solve the above technical problems is as follows:

[0006] A method for preparing a multifunctional polymer foam with high-efficiency antibacterial and photoinduced heating properties, comprising the following steps:

[0007] (1) Preparation of graphene polymer foam: Immerse the polymer foam in a graphene suspension and perform ultrasonic treatment to obtain it.

[0008] (2) Preparation of high / low-valent silver hybrid oxide coating: First, mix and heat a potassium persulfate solution and a potassium hydroxide solution, then add a silver nitrate solution and stir to react. Finally, collect the precipitate of high / low-valent silver hybrid oxide and disperse it in a mixed solution of a surfactant and carboxylated chitosan to obtain it.

[0009] (3) Preparation of multifunctional polymer foam: Spray the high / low-valent silver hybrid oxide coating obtained in step (2) on the surface of the graphene polymer foam obtained in step (1), and dry it to obtain it.

[0010] The beneficial effects of the present invention are as follows: In the present invention, graphene sheets are embedded on the surface of the polymer foam pore walls through ultrasonic treatment, and then high / low-valent silver hybrid oxide is attached to the surface of the graphene polymer foam through a high-speed spraying technique, successfully preparing a multifunctional polymer foam with excellent photothermal conversion effect and high-efficiency antibacterial property at the same time. The preparation method is simple and the preparation efficiency is high.

[0011] Further, in step (1), the polymer foam is a polyurethane or polyolefin open-cell foam material; the solvent of the graphene suspension includes any one of ethanol, dimethylformamide, benzene, dichloromethane, tetrahydrofuran, methyl ethyl ketone, cyclohexanone, ethyl acetate, and toluene; the mass fraction of graphene in the graphene polymer foam is 10%-15%.

[0012] Further, the polyolefin includes any one of polyethylene, polystyrene, ethylene-vinyl acetate copolymer (EVA), and ethylene propylene diene monomer (EPDM).

[0013] The beneficial effects of adopting the above further technical solution are as follows: The polymer substrate used in the present invention is a commercial porous polymer foam with an open-cell foam structure, which has been widely used in the purification and filtration of liquids and air. Compared with the porous structure of the usual non-woven fiber membrane, there are obvious differences. The foam pores have a more direct matching effect with the spherical structures of usual filtered particles including viruses and bacteria, so it is more conducive to the design and application of the high-performance filtration and purification structure of the product.

[0014] Further, in step (1), the concentration of the graphene dispersion is 5-40 mg / mL; the time of ultrasonic treatment is 10-60 min.

[0015] The beneficial effects of adopting the above further technical solution are as follows: Under the action of ultrasonic waves, the two-dimensional graphene sheets in the suspension attack the polymer foam skeleton with their sharp nano-thick edges, and finally exist in the form of fish-scale-like packages inserted tightly on the surface of the polymer substrate, thus having a firm and reliable bonding force with the polymer scaffold, rather than being deposited on the surface of the foam substrate in the usual way of lying flat and stacking layer by layer. This surface modification structure can also fully expose each graphene sheet layer to provide a large specific surface area for each, providing a material basis for the uniform dispersion of the subsequent hybrid silver oxide and the antibacterial and photothermal effects of the functionalized polymer foam.

[0016] Further, in step (2), the concentration of the potassium persulfate solution is 0.075 - 0.225 mol / L, the concentration of the potassium hydroxide solution is 1 - 3 mol / L, and the concentration of the silver nitrate solution is 0.05 - 0.1 mol / L; the volume ratio of the potassium persulfate solution, the potassium hydroxide solution, and the potassium nitrate solution is (1 - 3):(0.4 - 0.8):(2 - 4).

[0017] Further, in step (2), the temperature for mixed heating is 50 - 70 °C, and the stirring reaction time is 20 - 30 min.

[0018] Further, in step (2), the surfactant includes at least one of polyvinylpyrrolidone, polyvinyl alcohol, dimethylformamide, and polysorbate 80; the mass-volume ratio of the surfactant, carboxylated chitosan, and solvent in the surfactant and carboxylated chitosan mixed solution is 1 g:(1.2 - 5) g:(250 - 900) mL.

[0019] Further, the particle size range of the high / low-valent silver hybrid oxide particles obtained in step (2) is 75 - 120 nm.

[0020] Further, the high / low-valent silver hybrid oxide coating obtained in step (2) contains monovalent silver and divalent silver, and the mass ratio of monovalent silver to divalent silver is (1 - 4):(6 - 9).

[0021] Preferably, the mass ratio of monovalent silver to divalent silver in the high / low-valent silver hybrid oxide coating obtained in step (2) is 3:7.

[0022] Further, in step (3), spraying and drying are repeated 3 - 5 times, and the drying temperature is 50 - 80 °C.

[0023] Further, the mass fraction of the high / low-valent silver hybrid oxide in the multifunctional polymer foam obtained in step (3) is 0.1% - 4%.

[0024] Preferably, the mass fraction of the high / low-valent silver hybrid oxide in the multifunctional polymer foam obtained in step (3) is 0.3% - 1.2%.

[0025] The beneficial effects of adopting the above further technical solution are as follows: Through the synergistic effect of monovalent silver and divalent silver in the high / low-price silver hybrid oxide coating, the present invention achieves a stronger bactericidal effect compared with elemental silver and low-price anions.

[0026] A multifunctional polymer foam with high-efficiency antibacterial and photo-induced heating properties is prepared by the above preparation method.

[0027] Application of the above multifunctional polymer foam with high-efficiency antibacterial and photo-induced heating properties in air purification and disinfection.

[0028] The present invention has the following beneficial effects:

[0029] The multifunctional polymer foam prepared by the present invention simultaneously has excellent photothermal conversion effect and high-efficiency antibacterial property. On the one hand, under sunlight irradiation, it will produce a photothermal effect. After 2 minutes of illumination, its surface temperature can reach 72 °C, and it has excellent light illumination-cooling cycle stability, providing a guarantee for its application in photothermal and synergistic antibacterial functions. On the other hand, graphene with a large specific surface area not only increases the loading area of high / low-price silver hybrid oxide particles on the surface of the polymer foam, but also has a certain antibacterial effect itself. The synergistic effect of the two makes the product have a significant inhibitory effect on common Gram-negative bacteria - Escherichia coli and Gram-positive bacteria - Staphylococcus aureus, etc. Description of the Drawings

[0030] Figure 1 It is a transmission electron microscope picture of the high / low-price silver hybrid oxide in Test Example 1;

[0031] Figure 2 It is a surface SEM diagram of the multifunctional polymer foam and the commercial polymer foam in Test Example 1, where a is the commercial polymer foam and b is the multifunctional polymer foam;

[0032] Figure 3 It is a graph of the antibacterial experiment results of the multifunctional polymer foam and the commercial polymer foam in Test Example 1. Detailed Embodiments

[0033] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only used to explain the present invention and are not intended to limit the scope of the present invention. For those not specified in the examples, the conventional conditions or the conditions recommended by the manufacturer are followed. For the reagents or instruments not specified by the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0034] Example 1:

[0035] A preparation method of a multifunctional polymer foam with high-efficiency antibacterial and photo-induced heating properties includes the following steps:

[0036] (1) Preparation of Graphene Polymer Foam

[0037] Pretreatment of Polymer Foam:

[0038] After cutting the polyurethane open-cell foam material, it is placed in an ethanol solution with a volume fraction of 50% and ultrasonically cleaned for 20 min to remove impurities on the foam surface and improve its wettability, facilitating the loading of graphene.

[0039] Loading of Graphene:

[0040] The pretreated foam substrate is immersed in a beaker containing a graphene dispersion solution with a concentration of 20 mg / mL and subjected to ultrasonic treatment for 20 min, and then cleaned to remove the graphene that is not firmly attached, obtaining a graphene polymer foam with graphene sheets attached, where the mass fraction of graphene is 10%.

[0041] (2) Preparation of High / Low-Valent Silver Hybrid Oxide Coating

[0042] First, 0.6 mL of 1 mol / L potassium hydroxide solution is added to a beaker containing 2 mL of 0.075 mol / L potassium persulfate solution, and the mixed solution is heated in a water bath at 60 °C; then 3 mL of 0.08 mol / L silver nitrate solution is injected into the beaker, and the mixture is stirred and reacted for 30 min; finally, the black precipitate of high / low-valent silver hybrid oxide is collected, washed 3 times with deionized water until the pH = 7, and then filtered. The black solid is redispersed in a mixed solution of 280 mL containing 1 g of polyvinylpyrrolidone (Mw = 10000) and 1.4 g of carboxylated chitosan to obtain a high / low-valent silver hybrid oxide coating.

[0043] (3) Preparation of Multifunctional Polymer Foam

[0044] First, the graphene polymer foam obtained in step (1) is laid on a polytetrafluoroethylene plate, and then the high / low-valent silver hybrid oxide coating is placed in a spray gun. The spray gun is at a 90° angle to the plane of the graphene polymer foam and sprayed for 10 s, and then dried at 80 °C. The spraying and drying are repeated 3 times to obtain a multifunctional polymer foam.

[0045] Example 2:

[0046] A preparation method of a multifunctional polymer foam with high-efficiency antibacterial and photoinduced heating properties, comprising the following steps:

[0047] (1) Preparation of Graphene Polymer Foam

[0048] Pretreatment of Polymer Foam:

[0049] After cutting the polyurethane open-cell foam material, it was placed in an ethanol solution with a volume fraction of 50% and ultrasonically cleaned for 20 min to remove impurities on the foam surface while improving its wettability, facilitating the loading of graphene.

[0050] Graphene loading:

[0051] The pretreated foam substrate was immersed in a beaker containing a graphene dispersion solution with a concentration of 40 mg / mL and subjected to ultrasonic treatment for 20 min, and then washed to remove the graphene that was not firmly attached, obtaining a graphene polymer foam with graphene sheets attached, where the mass fraction of graphene was 15%.

[0052] (2) Preparation of high / low-valent silver hybrid oxide coating

[0053] First, 0.6 mL of 1 mol / L potassium hydroxide solution was added to a beaker containing 2 mL of 0.075 mol / L potassium persulfate solution, and the mixed solution was heated in a water bath at 60 °C; then 3 mL of 0.1 mol / L silver nitrate solution was injected into the beaker, and the mixture was stirred and reacted for 30 min; finally, the black precipitate of high / low-valent silver hybrid oxide was collected and washed 3 times with deionized water until the pH reached 7, and then filtered. The black solid was redispersed in a mixed solution of 420 mL containing 1 g of polyethylene glycol (Mw = 2000) and 2.1 g of carboxylated chitosan to obtain a high / low-valent silver hybrid oxide coating.

[0054] (3) Preparation of multifunctional polymer foam

[0055] First, the graphene polymer foam obtained in step (1) was laid on a polytetrafluoroethylene plate, and then the high / low-valent silver hybrid oxide coating was placed in a spray gun. The spray gun was at a 90° angle to the plane of the graphene polymer foam and sprayed for 10 s, and then dried at 50 °C. The spraying and drying were repeated 4 times to obtain a multifunctional polymer foam.

[0056] Example 3:

[0057] A preparation method of a multifunctional polymer foam with high-efficiency antibacterial and photoinduced heating properties, comprising the following steps:

[0058] (1) Preparation of graphene polymer foam

[0059] Polymer foam pretreatment:

[0060] After cutting the polyurethane open-cell foam material, it was placed in an ethanol solution with a volume fraction of 50% and ultrasonically cleaned for 20 min to remove impurities on the foam surface while improving its wettability, facilitating the loading of graphene.

[0061] Graphene loading:

[0062] The pretreated foam substrate was immersed in a beaker containing a graphene dispersion with a concentration of 15 mg / mL and subjected to ultrasonic treatment for 60 min, and then washed to remove the loosely attached graphene, resulting in a graphene polymer foam with graphene sheets attached, where the mass fraction of graphene was 13%.

[0063] (2) Preparation of high / low-valent silver hybrid oxide coating

[0064] First, 0.6 mL of 1 mol / L potassium hydroxide solution was added to a beaker containing 2 mL of 0.15 mol / L potassium persulfate solution, and the mixed solution was heated in a water bath at 60 °C; then 3 mL of 0.05 mol / L silver nitrate solution was injected into the beaker, and the mixture was stirred and reacted for 30 min; finally, the black precipitate of high / low-valent silver hybrid oxide was collected, washed 3 times with deionized water until the pH reached 7, and then filtered. The black solid was redispersed in 840 mL of a mixed solution containing 1 g of polyvinylpyrrolidone (Mw = 1300000) and 4.2 g of carboxylated chitosan to obtain the high / low-valent silver hybrid oxide coating.

[0065] (3) Preparation of multifunctional polymer foam

[0066] First, the graphene polymer foam obtained in step (1) was laid on a polytetrafluoroethylene plate, and then the high / low-valent silver hybrid oxide coating was placed in a spray gun. The spray gun was held at a 90° angle to the plane of the graphene polymer foam and sprayed for 10 s, and then dried at 60 °C. The spraying and drying process was repeated 5 times to obtain the multifunctional polymer foam.

[0067] Test Example 1:

[0068] (1) Physical and chemical property characterization

[0069] The high / low-valent silver hybrid oxide prepared in Example 1 was analyzed by transmission electron microscopy and XPS, and the multifunctional polymer foam prepared in Example 1 and a commercial polyurethane open-cell foam material were characterized by scanning electron microscopy. The experimental results are shown in Table 1 - Table 2 and Figure 1 - Figure 2 as follows.

[0070] Table 1 XPS analysis of high / low-valent silver hybrid oxide

[0071]

[0072] Table 2 Valence state proportion of silver element in high / low-valent silver hybrid oxide

[0073]

[0074] Tables 1 and 2 show the elemental analysis results of the high / low-valent silver hybrid oxide powder prepared by the present invention using XPS. It can be known from the results that the ratio of oxygen (O) to silver (Ag) in the high / low-valent silver hybrid oxide powder is 1:1, indicating a relatively high purity of AgO. In the AgO powder, the ratio of monovalent silver to divalent silver is 7:3. The successful preparation of divalent silver is one of the keys for the multifunctional polymer foam prepared by the present invention to achieve rapid antibacterial activity. Figure 1 The transmission electron microscope image of the high / low-valent silver hybrid oxide prepared by the present invention shows that the high / low-valent silver hybrid oxide prepared by the present invention is in the shape of irregular flakes with a particle size of 75 - 120 nm. Figure 2 Figure a in it shows the surface morphology of the commercial polymer foam. Figure 2 Figure b in it shows the surface morphology of the multifunctional polymer foam prepared in Example 1.

[0075] (2) Antibacterial performance

[0076] An antibacterial experiment was carried out on the multifunctional polymer foam material prepared in Example 1 of the present invention against Gram-positive bacteria (Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli). Commercial polymer foam and multifunctional polymer foam materials with a size of 10 mm × 10 mm × 0.6 mm were placed in a shaking tube. After adding the bacterial solution, they were shaken and cultured for 90 min, and then spread and cultured. The results of the antibacterial experiment are as Figure 3 shown.

[0077] It can be seen from the antibacterial results that the commercial polymer foam basically has no ability to inhibit the growth of Escherichia coli and Staphylococcus aureus, while the multifunctional polymer foam prepared in Example 1 of the present invention has a strong effect on both bacteria, and the survival rate is less than 0.1%. Among them, the sterilization efficiency against Escherichia coli reaches 100%.

[0078] (3) Air resistance and photothermal effect

[0079] A pressure gauge was used to measure the air flow pressure difference between the porous polymer foams prepared in Examples 1 - 3 and the commercial polymer foam. The results show that at a gas flow rate of 1.0 m / s, the air resistance is less than 40 MPa, and there is no significant change in the air resistance of the porous foam before and after modification.

[0080] The photothermal effect test was carried out on Example 1 and the commercial polymer foam. The test method was: irradiate under sunlight for 2 min, and measure its temperature at 20 s, 60 s, 90 s, and 120 s.

[0081] The experimental results are shown in Table 3.

[0082] Table 3 Results of the photothermal conversion experiment data

[0083]

[0084] As can be seen from Table 3, compared with commercial polymer foams, the multifunctional polymer foam prepared in Example 1 of the present invention has significantly better photothermal effects.

[0085] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for preparing a multifunctional polymer foam having high-efficiency antibacterial and photothermal properties, characterized in that: The following steps are involved: (1) Preparation of graphene polymer foam: immersing the polymer foam in a graphene suspension and ultrasonically treating the polymer foam; (2) Preparation of high / low-valent silver hybrid oxide coating: firstly, potassium persulfate solution and potassium hydroxide solution are mixed and heated, then silver nitrate solution is added and stirred for reaction, finally, the precipitated high / low-valent silver hybrid oxide is collected and dispersed in a mixed solution of surfactant and carboxylated chitosan to obtain; (3) Preparation of multifunctional polymer foam: spraying the high / low valent silver hybrid oxide coating obtained in step (2) onto the surface of the graphene polymer foam obtained in step (1), and drying to obtain the multifunctional polymer foam.

2. The method for preparing the multifunctional polymer foam with high-efficiency antibacterial and photothermal properties according to claim 1, characterized in that: The polymer foam in step (1) is a polyurethane or polyolefin open-cell foam material; the solvent of the graphene suspension includes any one of ethanol, dimethylformamide, benzene, dichloromethane, tetrahydrofuran, butanone, cyclohexanone, ethyl acetate and toluene; and the mass fraction of graphene in the graphene polymer foam is 10%-15%.

3. The method for preparing the multifunctional polymer foam with high-efficiency antibacterial and photothermal properties according to claim 1, characterized in that: In the step (1), the concentration of the graphene dispersion is 5-40 mg / mL; and the ultrasonic treatment time is 10-60 min.

4. The method for preparing the multifunctional polymer foam with high-efficiency antibacterial and photothermal properties according to claim 1, characterized in that: In the step (2), the concentration of the potassium persulfate solution is 0.075-0.225 mol / L, the concentration of the potassium hydroxide solution is 1-3 mol / L, and the concentration of the silver nitrate solution is 0.05-0.1 mol / L; the volume ratio of the potassium persulfate solution, the potassium hydroxide solution and the potassium nitrate solution is (1-3): (0.4-0.8): (2-4).

5. The method for preparing the multifunctional polymer foam with high-efficiency antibacterial and photothermal properties according to claim 1, characterized in that: The mixing and heating temperature in step (2) is 50-70° C., and the stirring reaction time is 20-30 min.

6. The method for preparing the multifunctional polymer foam with high-efficiency antibacterial and photothermal properties according to claim 1, characterized in that: The surfactant in step (2) comprises at least one of polyvinyl pyrrolidone, polyvinyl alcohol, dimethylformamide and polysorbate 80; the mass volume ratio of the surfactant, carboxylated chitosan and solvent in the mixed solution of the surfactant and carboxylated chitosan is 1g: (1.2-5)g: (250-900)mL.

7. The method for preparing the multifunctional polymer foam with high-efficiency antibacterial and photothermal properties according to claim 1, characterized in that: In the step (3), the spraying and drying are repeated 3-5 times, and the drying temperature is 50-80°C.

8. The method for preparing the multifunctional polymer foam with high-efficiency antibacterial and photothermal properties according to claim 1, characterized in that: The mass fraction of the high / low-valent silver hybrid oxide in the multifunctional polymer foam obtained in step (3) is 0.1%-4%.

9. A multifunctional polymer foam with high-efficiency antibacterial and photothermal properties, characterized in that: The method is prepared by the method according to any one of claims 1 to 8.

10. Use of the multifunctional polymer foam with high-efficiency antibacterial and photothermal properties as claimed in claim 9 in air purification and sterilization.

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