Reduced graphene oxide modified melt-blown cloth, preparation method thereof and filtering device

Abstract

The invention relates to reduced graphene oxide modified melt-blown cloth, a preparation method thereof and a filtering device. The preparation method of the reduced graphene oxide modified melt-blown cloth comprises the following steps: placing a melt-blown cloth in a graphene oxide dispersion liquid for ultrasonic treatment so as to form a graphene oxide coating layer on the surface of a fiber in the melt-blown cloth, and preparing the graphene oxide modified melt-blown cloth; and carrying out reduction treatment on the graphene oxide modified melt-blown cloth. The reduced graphene oxide modified melt-blown fabric prepared by the preparation method has relatively high filtering efficiency and relatively small filtering resistance, and also has relatively good antibacterial property.

Description

Technical Field

[0001] The present application relates to the field of material technology, and in particular to a reduced graphene oxide modified meltblown cloth, a preparation method thereof, and a filtering device. Background Art

[0002] Meltblown nonwoven fabric, also known as meltblown fabric, is a nonwoven fabric made of high molecular polymer as the main raw material and produced by meltblowing process. 2 The hybrid orbital is composed of a six-membered ring in a honeycomb-shaped two-dimensional carbon nanomaterial. It is a single carbon substance and one of the strongest materials known so far. It has strong tolerance, high hardness and good elasticity. It has a honeycomb network structure, a stable skeleton that is not easily destroyed, and exhibits good stability at room temperature. The composite of graphene and melt-blown nonwovens can improve the filtration performance, adsorption, infrared absorption and emission, and antibacterial and antibacterial properties of melt-blown nonwovens, and can be used in a variety of membrane separation fields such as air filtration, sewage treatment, temperature control, medical care, desalination, etc.

[0003] Traditional methods of compounding graphene and melt-blown nonwoven fabrics include: using graphene materials to modify polymer matrix, that is, mixing graphene materials and polymers, and then using melt-blown process to make melt-blown fibers and receive them into fabrics; or spraying graphene powder onto the still sticky surface of melt-blown fibers during the molding process to bond them into graphene-modified melt-blown nonwoven fabrics. However, the filtration resistance of graphene-modified melt-blown nonwoven fabrics prepared by traditional compounding methods is relatively large, and the filtration efficiency needs to be further improved. Summary of the invention

[0004] Based on this, the present application provides a reduced graphene oxide modified meltblown cloth with high filtration efficiency, a preparation method thereof, and a filtration device.

[0005] The technical solution of this application to solve the above technical problems is as follows.

[0006] On the one hand, the present application provides a method for preparing a melt-blown cloth modified by reduced graphene oxide, comprising the following steps:

[0007] placing a meltblown cloth in a graphene oxide dispersion for ultrasonic treatment to form a graphene oxide coating layer on the surface of fibers in the meltblown cloth to prepare a graphene oxide modified meltblown cloth;

[0008] The graphene oxide modified meltblown cloth is subjected to reduction treatment.

[0009] In some embodiments, in the method for preparing a melt-blown cloth modified with reduced graphene oxide, the concentration of the graphene oxide dispersion is 0.05 mg·mL -1 ~5 mg mL -1 .

[0010] In some of the embodiments, in the method for preparing reduced graphene oxide modified meltblown cloth, the power of the ultrasonic treatment is 300 W to 600 W, and the time is 1 s to 10 s.

[0011] In some embodiments, in the method for preparing a melt-blown fabric modified with reduced graphene oxide, the surface density of the melt-blown fabric is 10 g·m -2 ~100 g·m -2 ; and / or

[0012] The average diameter of the fibers in the meltblown cloth is 1 μm to 10 μm; and / or

[0013] The porosity of the meltblown cloth is 88% to 93%.

[0014] In some of the embodiments, in the method for preparing reduced graphene oxide modified meltblown cloth, the reduction treatment is performed by radiation reduction.

[0015] In some of the embodiments, in the method for preparing a melt-blown cloth modified by reduced graphene oxide, the wavelength of the radiation source used for the radiation reduction is 315 nm to 400 nm;

[0016] The power density of the irradiation reduction is 80 kW / m 2 ~ 100kW / m 2 ; and / or

[0017] The radiation reduction time is 1 min to 10 min.

[0018] In some of the embodiments, in the method for preparing the reduced graphene oxide modified meltblown cloth, after the ultrasonic treatment is completed, the method further includes the step of taking out and drying the meltblown cloth after the ultrasonic treatment.

[0019] In some of the embodiments, in the method for preparing meltblown cloth modified by reduced graphene oxide, after the reduction treatment step, the method further includes a step of electrostatically charging the composite material obtained in the reduction treatment step.

[0020] In some of the embodiments, in the method for preparing reduced graphene oxide modified meltblown cloth, the meltblown cloth includes polylactic acid meltblown cloth.

[0021] On the one hand, the present application provides a reduced graphene oxide modified meltblown cloth, which is prepared by the above-mentioned preparation method.

[0022] In some of the embodiments, in the reduced graphene oxide modified meltblown cloth, the graphene modified meltblown cloth includes a meltblown cloth and a graphene coating layer provided on the surface of the meltblown cloth.

[0023] In some of the embodiments, the mass proportion of graphene in the reduced graphene oxide modified meltblown cloth is 0.1%~1%.

[0024] On the one hand, the present application provides a filtering device, including the above-mentioned reduced graphene oxide modified meltblown cloth.

[0025] Compared with the prior art, the preparation method of reduced graphene oxide modified meltblown cloth of the present application has the following beneficial effects:

[0026] The preparation method of the reduced graphene oxide modified meltblown cloth of the present application comprises the following steps: placing the meltblown cloth in a graphene oxide dispersion for ultrasonic treatment, and utilizing the cavitation effect at the solid-liquid interface between the graphene oxide dispersion and the surface of the meltblown fibers in the meltblown cloth during ultrasonic propagation, so as to accelerate the mass transfer process at the solid-liquid interface, promote the graphene oxide dispersion to overcome the difference in affinity and wet the meltblown cloth, and at the same time drive the graphene oxide sheets in the graphene oxide dispersion to transfer from the liquid phase to the surface of the solid meltblown fibers, so as to form a tightly bonded graphene oxide coating layer on the surface of the fibers in the meltblown cloth; and then undergoing reduction treatment, a reduced graphene oxide modified meltblown cloth with a mesh porous structure is obtained without significantly changing the microscopic porous structure of the meltblown cloth, and the reduced graphene oxide modified meltblown cloth has high filtration efficiency, low filtration resistance, and good antibacterial properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present application and to more completely understand the present application and its beneficial effects, the following is a brief introduction to the drawings required for the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application, and those skilled in the art can obtain other drawings based on these drawings without creative work.

[0028] Figure 1 This is an optical microscopic image of the reduced graphene oxide coating layer on the surface of the melt-blown fiber in the reduced graphene oxide modified melt-blown cloth prepared in Example 1;

[0029] Figure 2 This is an optical microscopic image of the polylactic acid meltblown fabric prepared in step (1) of Example 1;

[0030] Figure 3 This is an optical microscopic image of the reduced graphene oxide coating layer on the surface of the melt-blown fibers in the reduced graphene oxide modified melt-blown cloth prepared in Comparative Example 2. DETAILED DESCRIPTION

[0031] The present application will be further described in detail below in conjunction with the accompanying drawings, implementation modes and examples. It should be understood that these implementation modes and examples are only used to illustrate the present application and are not used to limit the scope of the present application. The purpose of providing these implementation modes and examples is to make the understanding of the disclosure of the present application more thorough and comprehensive.

[0032] It should also be understood that the present application can be implemented in many different forms and is not limited to the embodiments and examples described herein. Those skilled in the art can make various changes or modifications without violating the connotation of the present application, and the equivalent forms obtained also fall within the scope of protection of the present application. For example, the features illustrated or described as part of one embodiment can be combined in another embodiment in a suitable manner to produce a new embodiment. In addition, in the description below, a large number of specific details are given in order to provide a more comprehensive understanding of the present application. It should be understood that the present application can be implemented without one or more of these details.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing implementation modes and embodiments and are not intended to limit this application.

[0034] Unless otherwise specified or incompatible herewith, the terms and phrases used herein shall have the following meanings:

[0035] In the present application, "plurality", "multiple", "multiple times", etc., unless otherwise specified, refer to a number greater than 2 or equal to 2. For example, "one or more" means one or greater than or equal to two.

[0036] As used herein, "combination thereof", "any combination thereof", "any combination thereof" etc. include all suitable combinations of any two or more of the listed items.

[0037] Herein, the “suitable” mentioned in “suitable combination”, “suitable method”, “any suitable method”, etc., shall be based on the ability to implement the technical solution of this application, solve the technical problems of this application, and achieve the expected technical effects of this application.

[0038] Herein, "preferred", "better", "more preferred", and "suitable" are only used to describe implementation methods or examples with better effects, and it should be understood that they do not constitute a limitation on the scope of protection of this application. If multiple "preferred" items appear in a technical solution, unless otherwise specified and there is no contradiction or mutual restriction, each "preferred" item is independent.

[0039] In the present application, "further", "further", "particularly" and the like are used for descriptive purposes to indicate differences in content, but should not be construed as limiting the scope of protection of the present application.

[0040] In this application, "optionally", "optional", and "optional" mean optional or dispensable, that is, any one of the two parallel schemes of "yes" or "no". If multiple "options" appear in a technical solution, unless otherwise specified and there is no contradiction or mutual restriction, each "optional" is independent.

[0041] In the present application, the terms "first", "second", "third", "fourth", etc. in "the first aspect", "the second aspect", "the third aspect", "the fourth aspect", etc. are used only for descriptive purposes and cannot be understood as indicating or implying relative importance or quantity, nor can they be understood as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first", "second", "third", "fourth", etc. only serve the purpose of non-exhaustive enumeration and description, and it should be understood that they do not constitute a closed limitation on quantity.

[0042] In the present application, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0043] In the present application, when it comes to a numerical interval (i.e., a numerical range), unless otherwise specified, the distribution of the optional numerical values ​​in the numerical interval is considered to be continuous, and includes the two numerical endpoints (i.e., the minimum value and the maximum value) of the numerical interval, and each numerical value between the two numerical endpoints. Unless otherwise specified, when the numerical interval only refers to the integers in the numerical interval, it includes the two endpoint integers of the numerical range, and each integer between the two endpoints, which is equivalent to directly listing each integer. When multiple numerical ranges are provided to describe features or characteristics, these numerical ranges can be combined. In other words, unless otherwise specified, the numerical range disclosed herein should be understood to include any and all sub-ranges included therein. The "numerical value" in the numerical interval can be any quantitative value, such as a number, a percentage, a ratio, etc. "Numerical interval" allows broadly including numerical interval types such as percentage intervals, ratio intervals, and ratio intervals.

[0044] The temperature parameters in this application, unless otherwise specified, are allowed to be either constant temperature treatment or to vary within a certain temperature range. It should be understood that the constant temperature treatment allows the temperature to fluctuate within the accuracy range controlled by the instrument. Fluctuations within the range of ±5°C, ±4°C, ±3°C, ±2°C, and ±1°C are allowed.

[0045] In this application, the term "room temperature" or "normal temperature" generally refers to 4°C to 35°C, for example, 20°C ± 5°C. In some embodiments of this application, "room temperature" or "normal temperature" refers to 10°C to 30°C. In some embodiments of this application, "room temperature" or "normal temperature" refers to 20°C to 30°C.

[0046] In this application, when referring to the unit of a data range, if there is a unit only after the right endpoint, it means that the units of the left and right endpoints are the same. For example, 3~5 h means that the units of the left endpoint "3" and the right endpoint "5" are both h (hours).

[0047] All documents mentioned in this application are cited as references in this application, just as each document is cited as reference separately. Unless they conflict with the invention purpose and / or technical solution of this application, the cited documents involved in this application are cited with all contents and all purposes. When the cited documents are involved in this application, the definitions of relevant technical features, terms, nouns, phrases, etc. in the cited documents are also cited. When the cited documents are involved in this application, the examples and preferred methods of the cited relevant technical features can also be incorporated into this application as references, but are limited to the implementation of this application. It should be understood that when the cited content conflicts with the description in this application, the present application shall prevail or be modified adaptively according to the description of this application.

[0048] The mass or weight of the relevant components mentioned in the specification of the embodiments of the present application may not only refer to the specific content of each component, but also indicate the proportional relationship of the mass or weight between the components. Therefore, as long as the content of the relevant components is proportionally enlarged or reduced according to the specification of the embodiments of the present application, it is within the scope disclosed in the specification of the embodiments of the present application. Specifically, the mass or weight described in the specification of the embodiments of the present application may be units known in the chemical industry such as μg, mg, g, and kg.

[0049] Graphene materials are used to mix and modify the polymer matrix, that is, after the graphene material and polymer are mixed, the melt-blown fiber is made by the melt-blown process and received into a cloth. The dispersion of graphene is poor, and it is difficult to give full play to the high specific surface area advantage of graphene, thus affecting the filtration resistance and filtration efficiency of the melt-blown cloth; during the molding process, graphene powder is sprayed onto the still sticky surface of the melt-blown fiber to bond it into a graphene-modified melt-blown non-woven fabric, which will change the pore structure of the melt-blown non-woven fabric, thereby affecting the filtration resistance, filtration efficiency and other properties of the melt-blown cloth, and there is also dust hazard.

[0050] After the graphene material is dispersed in the liquid phase, it is compounded with the meltblown cloth through chemical grafting, surface deposition, impregnation, etc. Since the polymer meltblown non-woven fabric material is not hydrophilic or has poor hydrophilicity, the graphene or meltblown cloth needs to be subjected to more complicated surface treatment and repeated operations, resulting in low preparation efficiency.

[0051] An embodiment of the present application provides a method for preparing a reduced graphene oxide modified meltblown cloth, comprising the following steps:

[0052] Step S10: placing the meltblown cloth in a graphene oxide dispersion for ultrasonic treatment to form a graphene oxide coating layer on the surface of the fibers in the meltblown cloth to prepare a graphene oxide modified meltblown cloth.

[0053] The meltblown cloth is placed in a graphene oxide dispersion for ultrasonic treatment. The cavitation effect at the solid-liquid interface between the graphene oxide dispersion and the meltblown fiber surface in the meltblown cloth during ultrasonic propagation can accelerate the mass transfer process at the solid-liquid interface, promote the graphene oxide dispersion to overcome the difference in affinity and wet the meltblown cloth, and drive the graphene oxide sheets in the graphene oxide dispersion to transfer from the liquid phase to the solid meltblown fiber surface, so as to form a tightly bonded graphene oxide coating layer on the surface of the fiber in the meltblown cloth. In some examples, in step S10, the concentration of the graphene oxide dispersion is 0.05 mg·mL -1 ~5 mg mL -1 .

[0054] It is understood that the concentration of the graphene oxide dispersion includes but is not limited to 0.05 mg·mL -1 , 0.1 mg·mL -1 , 0.15 mg·mL -1 , 0.2 mg·mL -1 , 0.25 mg·mL -1 , 0.3 mg·mL -1 , 0.35 mg·mL -1 , 0.4 mg·mL -1 , 0.45 mg·mL -1 , 0.5 mg·mL -1 , 0.8 mg·mL -1 , 1 mg·mL -1 , 1.5 mg·mL -1 , 2 mg·mL -1 , 2.5mg·mL -1 , 3 mg·mL -1 、3.5 mg·mL -1 , 4 mg·mL -1 , 4.5 mg·mL -1 , 5 mg·mL -1 ; In some examples, it can be within the range formed by any two of these point values ​​as end values, the same below.

[0055] In some of the examples, in step S10, the concentration of the graphene oxide dispersion is 0.05 mg·mL -1 ~3mg·mL -1 .

[0056] In some of the examples, in step S10, the concentration of the graphene oxide dispersion is 1 mg mL -1 ~3 mg mL -1 .

[0057] In some of the examples, in step S10, the power of the ultrasonic treatment is 300 W to 600 W, and the time is 1 s to 10 s.

[0058] It will be appreciated that the power of ultrasonic treatment includes but is not limited to 300 W, 320 W, 350 W, 380 W, 400 W, 420 W, 450 W, 480 W, 500 W, 520 W, 550 W, 580 W, and 600 W; the time of ultrasonic treatment includes but is not limited to 1 s, 2 s, 3 s, 4 s, 5 s, 6 s, 7 s, 8 s, 9 s, and 10 s.

[0059] In some of the examples, in step S10, the power of the ultrasonic treatment is 500 w to 600 w.

[0060] In some of the examples, in step S10, the ultrasonic treatment time is 8 s to 10 s.

[0061] In some of the examples, in step S10, the surface density of the meltblown fabric is 10 g·m -2 ~100 g·m -2 .

[0062] It is understood that the surface density of the meltblown cloth includes but is not limited to 10 g·m -2 , 15 g·m -2 , 20 g·m -2 , 25 g·m -2 、30 g·m -2 、35 g·m -2 , 40 g·m -2 45 g·m -2 , 50 g·m -2 , 55 g·m -2 、60 g·m -2 、65 g·m -2 、70 g·m -2 , 75 g·m -2 、80 g·m -2 、85 g·m -2 , 90 g·m-2 , 95 g·m -2 , 100 g·m -2 .

[0063] In some of the examples, in step S10, the surface density of the meltblown fabric is 25 g·m -2 ~60 g·m -2 .

[0064] In some of the examples, in step S10, the average diameter of the fibers in the meltblown cloth is 1 μm to 10 μm.

[0065] It will be appreciated that the average diameter of the fibers in the meltblown cloth includes, but is not limited to, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, and 10 μm.

[0066] In some of the examples, in step S10, the average diameter of the fibers in the meltblown cloth is 5 μm to 8 μm.

[0067] Optionally, the average diameter of the fibers in the meltblown cloth is 5 μm to 6 μm.

[0068] By controlling the average diameter of the fibers in the meltblown cloth, the filtration performance of the modified meltblown cloth can be further improved.

[0069] In some of the examples, in step S10, the porosity of the meltblown cloth is 88%~93%.

[0070] It can be understood that the porosity of meltblown cloth includes but is not limited to 88%, 89%, 90%, 91%, 92%, and 93%.

[0071] In some of the examples, in step S10, after the ultrasonic treatment is completed, the step of taking out and drying the meltblown cloth after the ultrasonic treatment is also included.

[0072] Furthermore, the drying temperature is ≤60°C, and the drying time is 5 s to 30 s.

[0073] Optionally, the drying temperature is 40°C to 60°C, and the drying time is 10 s to 20 s.

[0074] Furthermore, the drying is performed by blowing hot air, and it is understood that the temperature of the hot air is ≤ 60°C.

[0075] In some of the examples, in step S10, the meltblown cloth includes polylactic acid meltblown cloth.

[0076] Using biodegradable polylactic acid as the raw material of meltblown nonwoven fabrics makes the modified polylactic acid meltblown fabrics more environmentally friendly.

[0077] In some of the examples, in step S10, the preparation of the meltblown cloth includes the following steps:

[0078] The polymer raw materials of the meltblown fabric are melt-spun and bonded into a web in sequence.

[0079] Furthermore, the polymer raw material of the meltblown cloth is heated and melted by a twin-screw extruder to form a polymer melt, which is then transported to the spinning hole by a melt metering pump for extrusion. The polymer melt moves with the high-temperature and high-speed air outside the spinning hole and deforms and stretches to form meltblown fibers, which are randomly interlaced with each other on a receiving plane, bonded together, and cooled to room temperature to form a meltblown cloth.

[0080] It is understood that in some of these examples, the polymer raw material of the meltblown fabric includes polylactic acid.

[0081] Step S20: performing a reduction treatment on the graphene oxide modified meltblown cloth prepared in step S10.

[0082] The graphene oxide modified meltblown cloth prepared in step S10 is subjected to reduction treatment to obtain a reduced graphene oxide modified meltblown cloth with a mesh porous structure without significantly changing the microscopic porous structure of the meltblown cloth. The reduced graphene oxide modified meltblown cloth has high filtration efficiency, low filtration resistance, and good antibacterial properties.

[0083] In the preparation method of the reduced graphene oxide modified meltblown cloth of the present application, the reduced graphene oxide flakes are dispersed on the surface of the formed meltblown cloth fibers and form a coating layer, so that the high specific surface area advantage of the reduced graphene oxide can be brought into play, so that the reduced graphene oxide modified meltblown cloth has higher filtration efficiency and smaller filtration resistance.

[0084] The preparation method of the reduced graphene oxide modified meltblown cloth of the present application does not require a melt mixing process, does not require a dust spraying process, and does not require a surface chemical treatment, thereby avoiding the influence of graphene materials on the flow properties of polymer melts and the influence of the powder mixing process on the environment. Under the conditions of no blending process, no surface chemical treatment, and no dust spraying, efficient composite of graphene materials and meltblown cloth is achieved, which is environmentally friendly.

[0085] The preparation method of the reduced graphene oxide modified meltblown cloth of the present application can promote the application of graphene-modified polymer meltblown nonwoven materials in the fields of filtration, adsorption, medical hygiene, etc.

[0086] In some of the examples, in step S20, the reduction treatment is performed by radiation reduction.

[0087] In some of the examples, in step S21, the wavelength of the radiation source used for radiation reduction is 315 nm to 400 nm.

[0088] It will be appreciated that the wavelength of the radiation source used for radiation reduction includes but is not limited to 315 nm, 320 nm, 325 nm, 330 nm, 335 nm, 340 nm, 345 nm, 350 nm, 355 nm, 360 nm, 365 nm, 370 nm, 375 nm, 380 nm, 385 nm, 390 nm, 395 nm, and 400 nm.

[0089] In some of the examples, in step S21 , the wavelength of the radiation source used for radiation reduction is 365 nm.

[0090] In some of the examples, in step S21, the power density of the irradiation reduction is 80 kW / m 2 ~ 100kW / m 2 .

[0091] It is understood that the power density of radiation reduction includes but is not limited to 80 kW / m 2 , 90 kW / m 2 , 100kW / m 2 .

[0092] In some of the examples, in step S21, the radiation reduction time is 1 min to 10 min.

[0093] It will be understood that the time for irradiation reduction includes but is not limited to 1 min, 2 min, 3 min, 4 min, 5 min, 6 min, 7 min, 8 min, 9 min, and 10 min.

[0094] In some of the examples, in the method for preparing the reduced graphene oxide modified meltblown cloth, after step S20 is completed, step S30 is further included:

[0095] The composite material obtained in step S20 is subjected to electrostatic charging.

[0096] In some of the examples, in step S30, the voltage of the electrostatic electret is 30 kV to 60 kV.

[0097] It can be understood that the voltage of the electrostatic charge includes but is not limited to 30 kV, 40 kV, 50 kV, and 60 kV.

[0098] Furthermore, the voltage of the electrostatic charge is 60 kV.

[0099] One embodiment of the present application provides a reduced graphene oxide modified meltblown cloth, which is prepared by the above-mentioned preparation method.

[0100] In some of the examples, the reduced graphene oxide modified meltblown fabric includes a meltblown fabric and a reduced graphene oxide coating layer disposed on the surface of the meltblown fabric.

[0101] It can be understood that the meltblown fibers in the meltblown cloth are randomly arranged and staggeredly bonded to form a microscopic mesh porous structure; the reduced graphene oxide sheet layer is coated on the surface of the meltblown fibers to form a reduced graphene oxide coating layer and together constitute a microscopic network porous structure.

[0102] In some of these examples, the mass proportion of reduced graphene oxide in the reduced graphene oxide modified meltblown fabric is 0.1%~1%.

[0103] It can be understood that the mass proportion of reduced graphene oxide in the reduced graphene oxide modified meltblown fabric refers to the mass of reduced graphene oxide in the reduced graphene oxide modified meltblown fabric accounting for 0.1% to 1% of the total mass of the reduced graphene oxide modified meltblown fabric. Further, the mass proportion of reduced graphene oxide in the reduced graphene oxide modified meltblown fabric includes but is not limited to 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, and 1.0%.

[0104] The reduced graphene oxide modified meltblown cloth provided in the present application has high filtration efficiency and small filtration resistance, and also has good antibacterial properties, especially good antibacterial rates against Staphylococcus aureus, Escherichia coli, and Candida albicans.

[0105] In some of the examples, the filtration efficiency of reduced graphene oxide modified meltblown cloth for sodium chloride aerosol with an aerodynamic diameter of 0.25 μm is ≥90% and the filtration resistance is ≤30 Pa under ventilation conditions of 32 L / min.

[0106] In some of the examples, the antibacterial rates of reduced graphene oxide-modified meltblown cloth against Staphylococcus aureus, Escherichia coli, and Candida albicans were ≥90%.

[0107] One embodiment of the present application provides a filtering device, comprising the above-mentioned reduced graphene oxide modified meltblown cloth.

[0108] The filter device uses the above-mentioned reduced graphene oxide modified meltblown cloth, which can give the filter device higher filtration efficiency and smaller filtration resistance, and also give the filter device better antibacterial properties.

[0109] It will be understood that the filtering device includes but is not limited to medical masks, air purifiers, industrial air filtration systems, automobile air conditioning filters, water purifiers, etc.

[0110] The present application is further described in detail below in conjunction with specific implementation methods, but the implementation methods of the present application are not limited thereto.

[0111] Example 1

[0112] (1) The fiber-grade polylactic acid was dried at 100°C, heated to melt at 220°C, and transported to a spinning plate at 230°C through a screw and a metering pump. -1 The average fiber diameter was 5 μm and the surface density was 25 g·m -2 Polylactic acid meltblown cloth;

[0113] (2) The polylactic acid meltblown fabric prepared in step (1) was immersed in 1 mg ml -1 The melt-blown cloth modified with graphene oxide was prepared by adding the melt-blown cloth to a graphene oxide aqueous dispersion and applying 300 W ultrasonic treatment for 1 s. The melt-blown cloth was taken out after draining the excess dispersion and drying it with hot air at 40°C for 10 s.

[0114] (3) The graphene oxide modified meltblown fabric prepared in step (2) was irradiated and reduced at a wavelength of 365 nm (power density 80 kW / m 2 ) for 3 min and 60 kV electrostatic electret to obtain reduced graphene oxide modified melt-blown cloth; the content of reduced graphene oxide in the reduced graphene oxide modified melt-blown cloth is 0.4%.

[0115] The optical microscopic image of the graphene oxide coating layer on the surface of the melt-blown fiber in the graphene oxide modified melt-blown cloth prepared in step (2) of Example 1 is as follows: Figure 1 As shown; the optical microscopic image of the polylactic acid meltblown fabric prepared in step (1) is as shown Figure 2 shown.

[0116] from Figure 1~Figure 2 It can be seen that the meltblown fabric fibers are interwoven to form an irregular mesh porous structure. After being modified with graphene oxide, a graphene oxide coating layer is formed on the fiber surface, and the porous structure of the fiber is retained.

[0117] Examples 2 to 10 are basically the same as Example 1, wherein one or more of the parameters such as the average diameter of the fibers in the meltblown cloth obtained in step (1), the surface density of the meltblown cloth, or the concentration of the graphene oxide dispersion in step (2), the power of ultrasonic treatment, the time of ultrasonic treatment, or the power density and time of irradiation reduction in step (3) are different, as shown in Table 1.

[0118] Comparative Example 1

[0119] The method is basically the same as Example 1, except that in step (2), the polylactic acid meltblown cloth is immersed in water, as follows:

[0120] (1) The fiber-grade polylactic acid was dried at 100°C, heated to melt at 220°C, and transported to a spinning plate at 230°C through a screw and a metering pump. -1 The average fiber diameter was 5 μm and the surface density was 25 g·m -2 Polylactic acid meltblown cloth;

[0121] (2) The polylactic acid meltblown fabric was immersed in water and subjected to 300 W ultrasonic treatment for 1 s. The fabric was then taken out and the excess water dispersion was drained. The fabric was dried by hot air blowing at 40 °C for 10 s and irradiated with 365 nm wavelength (power density 80 kW / m 2 ) for 3 min and 60kV electrostatic charging to obtain the modified melt-blown cloth.

[0122] Comparative Example 2

[0123] The method is basically the same as Example 1, except that in step (2), the graphene oxide aqueous dispersion is applied to the surface of the polylactic acid meltblown cloth by blade coating, as follows:

[0124] (1) The fiber-grade polylactic acid was dried at 100°C, heated to melt at 220°C, and transported to a spinning plate at 230°C through a screw and a metering pump. -1 The average fiber diameter was 5 μm and the surface density was 25 g·m -2 Polylactic acid meltblown cloth;

[0125] (2) 1 mg ml -1 The graphene oxide aqueous dispersion was heated to 50 mL·m -2 Apply the coating to one side of the polylactic acid meltblown fabric and dry it with hot air at 40°C for 10 s;

[0126] (3) The graphene oxide modified meltblown fabric prepared in step (2) was irradiated and reduced at a wavelength of 365 nm (power density 80 kW / m 2 ) for 3 min and 60 kV electrostatic electret to obtain reduced graphene oxide modified melt-blown cloth.

[0127] The optical microscopic image of the graphene oxide coating layer on the surface of the melt-blown fiber in the graphene oxide modified melt-blown cloth prepared in step (2) of comparative example 2 is as follows: Figure 3 shown.

[0128] from Figure 3 It can be seen that graphene oxide overlaps the fibers to form a thin film on the surface of the meltblown cloth, eventually covering a large area of ​​the fiber mesh porous structure of the meltblown cloth.

[0129] Comparative Example 3

[0130] The same as Example 1, except that in step (2), the polylactic acid meltblown cloth is immersed in 1 mg ml -1 The graphene oxide aqueous dispersion was not subjected to ultrasonic treatment, as follows:

[0131] (1) The fiber-grade polylactic acid was dried at 100°C, heated to melt at 220°C, and transported to a spinning plate at 230°C through a screw and a metering pump. -1 The average fiber diameter was 5 μm and the surface density was 25 g·m -2 Polylactic acid meltblown cloth;

[0132] (2) immersing the polylactic acid meltblown cloth prepared in step (1) into a 1 mg ml-1 graphene oxide aqueous dispersion, applying 300 W ultrasonic treatment for 1 s, then taking it out, draining the excess dispersion, and drying it with hot air at 40°C for 10 s to prepare a graphene oxide modified meltblown cloth;

[0133] (3) The graphene oxide modified melt-blown fabric prepared in step (2) was irradiated and reduced at a wavelength of 365 nm (power density 80 kW / m2) for 3 min and subjected to 60 kV electrostatic charging to obtain a reduced graphene oxide modified melt-blown fabric.

[0134] Comparative Example 4

[0135] Graphene and fiber-grade polylactic acid were dried at 100°C, and the mass of graphene accounted for 0.4% of the total mass of graphene-modified melt-blown cloth. The dried graphene and fiber-grade polylactic acid were added into a screw extruder, heated and melted at 220°C, and transported to a spinning plate at 230°C through a screw and a metering pump, and then subjected to a spinning process at 250°C and 9 m·s -1 The average fiber diameter was 10 μm and the surface density was 25 g·m -2 Graphene / polylactic acid meltblown cloth.

[0136] Table 1

[0137]

[0138] The modified meltblown fabrics prepared in the embodiments and comparative examples were used as filter layers in disposable respiratory filters to test the particle filtration efficiency (T / JSAS 031-2022), filtration resistance (T / JSAS 031-2022) and antibacterial rate (GB / T 20944.3-2008, Staphylococcus aureus, Escherichia coli, Candida albicans) of the disposable respiratory filters. The test results are shown in Table 2.

[0139] Table 2

[0140]

[0141] As can be seen from Table 2, compared with Comparative Example 1 in which the polylactic acid meltblown cloth is immersed in water instead of graphene oxide aqueous dispersion, Comparative Example 2 in which the graphene oxide aqueous dispersion is applied on the surface of the polylactic acid meltblown cloth by scraping, and Comparative Example 3 in which the polylactic acid meltblown cloth is immersed in 1 mg ml -1 The graphene oxide aqueous dispersion was not ultrasonically treated, and the graphene and fiber-grade polylactic acid were simultaneously melt-spun into melt-blown cloth in Comparative Example 4. The reduced graphene oxide modified melt-blown cloth prepared in each embodiment has high filtration efficiency, small filtration resistance, and good antibacterial properties. Among them, in Comparative Example 2, the graphene oxide aqueous dispersion was applied to the surface of the polylactic acid melt-blown cloth by scraping, and its filtration resistance reached 1500 Pa, which would cause suffocation to the individual wearer and increase the energy consumption of the air filter.

[0142] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0143] The above-described embodiments only express several implementation methods of the present application, which is convenient for understanding the technical solution of the present application in detail, but it cannot be understood as limiting the scope of protection of the invention patent. It should be pointed out that for ordinary technicians in this field, without departing from the concept of the present application, several modifications and improvements can be made, which all belong to the scope of protection of the present application. It should be understood that the technical solutions obtained by those skilled in the art through logical analysis, reasoning or limited experiments on the basis of the technical solutions provided in the present application are all within the scope of protection of the claims attached to the present application. Therefore, the scope of protection of the patent of this application shall be based on the contents of the attached claims, and the description and drawings can be used to explain the contents of the claims.

Claims

1. A method for preparing a meltblown cloth modified by reduced graphene oxide, characterized in that: The following steps are involved: placing a meltblown cloth in a graphene oxide dispersion for ultrasonic treatment to form a graphene oxide coating layer on the surface of fibers in the meltblown cloth to prepare a graphene oxide modified meltblown cloth; The graphene oxide modified meltblown cloth is subjected to reduction treatment.

2. The preparation method according to claim 1, characterized in that The concentration of the graphene oxide dispersion is 0.05 mg·mL -1 ~5 mg mL -1 .

3. The preparation method according to claim 1, characterized in that: The power of the ultrasonic treatment is 300 W to 600 W, and the time is 1 s to 10 s.

4. The preparation method according to claim 1, characterized in that: The surface density of the meltblown cloth is 10 g·m -2 ~100g·m -2 ; and / or The average diameter of the fibers in the meltblown cloth is 1 μm to 10 μm; and / or The porosity of the meltblown cloth is 88% to 93%.

5. The preparation method according to any one of claims 1 to 4, characterized in that The reduction treatment is carried out by radiation reduction.

6. The preparation method according to claim 5, characterized in that: The wavelength of the radiation source used in the radiation reduction is 315 nm to 400 nm; The power density of the irradiation reduction is 80 kW / m 2 ~ 100kW / m 2 ; and / or The radiation reduction time is 1 min to 10 min.

7. The preparation method according to any one of claims 1 to 4 and 6, characterized in that: After the ultrasonic treatment is completed, the process also includes taking out and drying the meltblown cloth after the ultrasonic treatment.

8. The preparation method according to any one of claims 1 to 4 and 6, characterized in that: After the reduction treatment step, the method further includes a step of subjecting the composite material obtained in the reduction treatment step to electrostatic charging.

9. The preparation method according to any one of claims 1 to 4 and 6, characterized in that: The meltblown cloth comprises polylactic acid meltblown cloth.

10. A reduced graphene oxide modified meltblown cloth, characterized in that: The method is prepared according to any one of claims 1 to 9.

11. The reduced graphene oxide modified meltblown fabric according to claim 10, characterized in that: The graphene-modified meltblown cloth comprises a meltblown cloth and a reduced graphene oxide coating layer arranged on the surface of the meltblown cloth.

12. The reduced graphene oxide modified meltblown fabric according to claim 11, characterized in that: The mass proportion of reduced graphene oxide in the reduced graphene oxide modified meltblown cloth is 0.1% to 1%.

13. A filtering device, characterized in that: It comprises the reduced graphene oxide modified meltblown cloth as described in any one of claims 10 to 12.

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