Modular Melt Electrospinning Device for Ultrafine Fibers, Expansion Method and Application

Abstract

The present invention belongs to the technical field of melt electrospinning equipment, and discloses a modular melt electrospinning device for ultrafine fibers, an expansion method and an application. The method includes: freely combining and splicing a plurality of sub-modules with transverse and longitudinal hot channels formed inside to form an expandable module assembly, and adjusting the melt flow rate in the nozzles connected to each sub-module through the installed screw regulators, so that each nozzle generates ultrafine fibers with the actually required diameter. The present invention overcomes the defect of the original technology that when changing the number of nozzles for a large module, the entire large module needs to be reprocessed. The expandable small modules can be reused, greatly reducing the cost of industrial production; since the modules are independent of each other, it is more convenient for maintenance. Whichever nozzle is damaged can be replaced, overcoming the problem of inconvenient maintenance in the original technology.

Description

Technical Field

[0001] The present invention belongs to the technical field of melt electrostatic spinning equipment, and in particular relates to a modular melt electrostatic spinning device for ultrafine fibers, an expansion method and an application thereof. Background Art

[0002] Nanofibers have application advantages in many fields and have received attention from the industry. These fields include: air filtration, liquid filtration, energy battery diaphragms, biomedicine, sound absorbing materials, etc. There are many methods to manufacture nanofibers, such as stretching, template synthesis, self-assembly, microphase separation, electrospinning, etc. Among them, electrospinning is divided into solution electrospinning and melt electrospinning. At present, solution electrospinning has initially achieved industrial production. However, solution electrospinning has high requirements for environmental humidity and temperature, the solvent is easy to volatilize during the spinning process, and the spinning efficiency is low. In comparison, melt electrospinning can make up for the shortcomings of solution electrospinning to some extent, so melt electrospinning has become a new hotspot for industrial production.

[0003] The application of melt electrospinning in the industrial production process generally adopts the nozzle array method to produce fiber felts with a certain width, and uses a whole module to process the flow channel through hot runner technology, and then installs the nozzle on the module to obtain a fiber felt with a certain width.

[0004] The equipment for large-scale electrospinning is designed in advance. The entire module is fixed, and the number of nozzles is fixed and cannot be expanded. If you want to get fiber mats of other widths, you need to reprocess new modules and hot runners. The entire module is complex to process and the cost is high. Due to the different pressures in the flow channel, the flow rate of each spinning nozzle is uncontrollable, resulting in uneven fiber diameter. Since the module is a whole, if it is blocked, the entire module needs to be disassembled, which is inconvenient for maintenance.

[0005] Through the above analysis, the problems and defects of the prior art are as follows:

[0006] (1) Existing modules are all large, integrated modules that are not reusable and have high production costs.

[0007] (2) The existing large-scale electrospinning equipment has uncontrollable nozzle flow, is inconvenient to maintain and cannot be expanded, resulting in low production efficiency and the inability to further improve the product quality pass rate.

[0008] (3) The nozzles of existing large-scale electrospinning equipment are difficult to replace and maintain. Summary of the invention

[0009] The present invention is composed of multiple different sub - modules spliced into an expandable module assembly, which overcomes the problems of non - reusable and non - expandable modules in the prior art, and further improves production efficiency; moreover, the modules and the nozzles are independent of each other and can be disassembled or replaced separately, overcoming the problem of inconvenient replacement or maintenance in the prior art; the flow rate of each nozzle can be adjusted, and the diameter of the fibers generated by the nozzle can be precisely controlled, so that each nozzle generates fibers with a uniform diameter, overcoming the problem of uncontrollable nozzle flow rate in the prior art.

[0010] To overcome the problems existing in the related art, the disclosed embodiments of the present invention provide a modular melt electrospinning device, an expansion method and an application for ultrafine fibers.

[0011] The technical solution is as follows: An expansion method for a modular melt electrospinning device for ultrafine fibers, comprising:

[0012] Fix the first intermediate sub - module with transverse and longitudinal hot channels inside to the support frame, and then combine and splice multiple other sub - modules with the same structure as the first intermediate sub - module in a certain order to form an expandable module assembly. The expandable module assembly can increase or decrease the number of sub - modules according to actual needs in industrial production to meet the requirements; each of the sub - modules is equipped with a thread adjuster, and the flow rate of the melt in the nozzle connected to the sub - module is adjusted by thread rotation, so that each nozzle generates ultrafine fibers with the actual required diameter.

[0013] In one embodiment, splicing structures are provided on the sub - modules for seamless splicing of the sub - modules in a certain order; the splicing structures include protrusions and depressions, which are located on different sides of the sub - module respectively.

[0014] In one embodiment, the hot channels opened inside each sub - module are accurately docked with the transverse hot channels of adjacent sub - modules.

[0015] In one embodiment, after the expandable module assembly is spliced, the hot channels in the outermost circle of the expandable module assembly are blocked with wooden plugs or rubber plugs, so that the melt flows inside the expandable module assembly and prevents the melt from flowing out.

[0016] Another object of the present invention is to provide a modular melt electrospinning device for ultrafine fibers implementing an expansion method of the modular melt electrospinning device for ultrafine fibers, comprising: an extruder, and a support frame fixed on a working platform, wherein the support frame is fixedly provided with an expandable module assembly through bolts, and a melt inlet of the expandable module assembly is connected to the extruder; the expandable module assembly is connected with a nozzle through module fixing threads, and the nozzle is communicated with a thread adjuster installed on the expandable module assembly, and the thread adjuster is used for adjusting the flow rate of the melt in the nozzle, so as to enable each nozzle to generate ultrafine fibers with an actually required diameter.

[0017] In one embodiment, the expandable module assembly is freely combined and spliced by a plurality of sub-modules with transverse and longitudinal hot channels opened inside;

[0018] The sub-modules include a first intermediate sub-module, a second peripheral sub-module, a third peripheral sub-module, a fourth peripheral sub-module and a fifth peripheral sub-module;

[0019] The first intermediate module is fixedly installed at the exact center above the support frame through bolts, and a melt inlet is arranged directly above the first intermediate sub-module and is connected to the extruder;

[0020] The second peripheral sub-module, the third peripheral sub-module, the fourth peripheral sub-module and the fifth peripheral sub-module are spliced on the first intermediate sub-module through a splicing structure.

[0021] In one embodiment, the first intermediate sub-module, the second peripheral sub-module, the third peripheral sub-module, the fourth peripheral sub-module and the fifth peripheral sub-module are all fixedly installed above the support frame through bolts.

[0022] Another object of the present invention is to provide a 3×3 modular melt electrospinning device expanded by using the expansion method of the modular melt electrospinning device for ultrafine fibers.

[0023] Another object of the present invention is to provide a 6×6 modular melt electrospinning device expanded by using the expansion method of the modular melt electrospinning device for ultrafine fibers.

[0024] Another object of the present invention is to provide an application of the expansion method of the modular melt electrospinning device for ultrafine fibers in the preparation of nanofibers for air filtration, liquid filtration, energy / battery separators, biomedicine, and sound absorption materials.

[0025] Combining all the above technical solutions, the advantages and positive effects possessed by the present invention are as follows:

[0026] First, in view of the technical problems existing in the above-mentioned prior art and the difficulty of solving these problems, closely combining with the technical solution to be protected by the present invention, as well as the results and data during the R & D process, etc., analyze in detail and profoundly how the technical solution of the present invention solves the technical problems and the creative technical effects brought about after solving the problems. The specific description is as follows: The present invention overcomes the problems of uncontrollable nozzle flow rate, inconvenient maintenance, and non-expandability.

[0027] The present invention provides a modular melt electrospinning device for ultrafine fibers. Compared with the traditional melt electrospinning device for mass-producing ultrafine fibers, the original entire fixed module of the present invention is composed of several small modules. A hot runner is processed in each small module. According to actual needs, the small modules are spliced into an expandable module combination to achieve the expandability of the modules. Since each small module is independent of the nozzle, it is also convenient for maintenance. The flow rate of the nozzle can also be adjusted by threads, so that each nozzle can produce ultrafine fibers with a uniform diameter.

[0028] Second, regarding the technical solution as a whole or from the perspective of the product, the technical effects and advantages of the technical solution to be protected by the present invention are specifically described as follows:

[0029] The present invention provides a modular melt electrospinning device for ultrafine fibers. Multiple groups of nozzles and modules are distributed in an array to produce a fiber mat with a certain width, which can increase the output and simplify the industrialization process of melt electrospinning.

[0030] Compared with the prior art, in industrial production, for the modular melt electrospinning device for ultrafine fibers, compared with the entire large module, each module is independent. The number of expandable module combinations can be spliced according to the needs of industrial production. The entire large module is replaced by expandable small modules. Moreover, the expandable small modules overcome the defect of the original large module that the entire large module needs to be reprocessed when the number of nozzles is changed. The expandable small modules can be reused, greatly reducing the cost of mass-producing ultrafine fibers in industrial production; since the modules are independent of each other, it is more convenient for maintenance. Which nozzle is damaged can be replaced, overcoming the problem of inconvenient maintenance in the prior art; the flow rate of each nozzle can be adjusted by threads so that the flow rate of each nozzle tends to be consistent in industrial production, thereby enabling each nozzle to produce ultrafine fibers with a uniform diameter.

[0031] Third, as the creative auxiliary evidence of the claims of the present invention, it is also reflected in the following important aspects:

[0032] (1) In the industrial mass production of ultrafine fibers, the present invention greatly improves the production efficiency while reducing the production cost and simplifying the production process;

[0033] (2) The present invention breaks through the application bottleneck of this technology at home and abroad, and the sub-modules spliced into an expandable module assembly will be quickly and widely applied to the entire industry;

[0034] (3) The technical solution of the present invention overcomes three major problems of the prior art: it overcomes the problems of non-reusable and non-expandable modules in the original technology; it overcomes the problem of inconvenience in replacement or maintenance in the original technology; it overcomes the problem of uncontrollable nozzle flow rate in the original technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The accompanying drawings here are incorporated into the specification and form a part of this specification, showing embodiments consistent with the present disclosure, and are used together with the specification to explain the principles of the present disclosure;

[0036] Figure 1 is a schematic diagram of a modular melt electrospinning device for ultrafine fibers provided by an embodiment of the present invention;

[0037] Figure 2 is a three-dimensional schematic diagram of a modular melt electrospinning device for ultrafine fibers provided by an embodiment of the present invention;

[0038] Figure 3 is a three-dimensional schematic diagram of a 5×5 module splicing main structure provided by an embodiment of the present invention;

[0039] Figure 4 is a schematic diagram of the main structure of a single sub-module and a nozzle provided by an embodiment of the present invention;

[0040] Figure 5 is a three-dimensional structure schematic diagram of the module splicing sequence provided by an embodiment of the present invention (taking a 3×3 module as an example);

[0041] In the figure: 1, extruder; 2, expandable module assembly; 2-1, first intermediate sub-module; 2-2, second peripheral sub-module; 2-3, third peripheral sub-module; 2-4, fourth peripheral sub-module; 2-5, fifth outer peripheral module; 3, hot runner; 4, support frame; 5, nozzle; 6, thread adjuster; 7, bolt; 8, sub-module fixing thread. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0042] To make the above objects, features, and advantages of the present invention more apparent and understandable, the following detailed description of the specific embodiments of the present invention is made with reference to the accompanying drawings. Many specific details are set forth in the following description to fully understand the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0043] I. Explanation of the embodiment:

[0044] An embodiment of the present invention provides an expansion method for a modular melt electrospinning device of ultrafine fibers, including:

[0045] First, fix the first intermediate sub-module 2-1 with horizontal and vertical hot runners 3 inside to the support frame 4, and then combine and splice multiple other sub-modules with the same structure as the first intermediate sub-module 2-1 in a certain order to form an expandable module assembly 2. The expandable module assembly 2 can increase or decrease the number of sub-modules according to actual needs in industrial production to meet the requirements; each sub-module is equipped with a thread adjuster 6, and the melt flow rate in the nozzle 5 connected to the sub-module is adjusted by thread rotation, so that each nozzle 5 produces ultrafine fibers with the actual required diameter.

[0046] Exemplarily, the other sub-modules include a second peripheral sub-module 2-2, a third peripheral sub-module 2-3, a fourth peripheral sub-module 2-4, and a fifth peripheral sub-module 2-5.

[0047] In the embodiment of the present invention, splicing structures are provided on the sub-modules for seamless splicing between the sub-modules in a certain order; the splicing structures include protrusions and depressions, which are located on different sides of the sub-modules respectively. Embodiment

[0048] Such as Figure 1 、 Figure 2 As shown, an embodiment of the present invention provides a modular melt electrospinning device for ultrafine fibers, including an extruder 1, an expandable module assembly 2, a hot runner 3, a support frame 4, a nozzle 5, a thread adjuster 6, and a bolt 7; the expandable module assembly 2 includes five types of sub-modules, including a first intermediate sub-module 2-1, a second peripheral sub-module 2-2, a third peripheral sub-module 2-3, a fourth peripheral sub-module 2-4, and a fifth peripheral sub-module 2-5;

[0049] The support frame 4 is horizontally fixed on the working platform, and the first intermediate module 2-1 in the expandable module assembly 2 is fixed to the exact center position above the support frame 4 through the bolt 7. The melt inlet is located directly above the first intermediate sub-module 2-1 and is connected to the extruder 1, as Figure 2 、 Figure 3 shown;

[0050] The second peripheral sub-module 2-2, the third peripheral sub-module 2-3, the fourth peripheral sub-module 2-4, and the fifth peripheral sub-module 2-5 are spliced onto the first intermediate sub-module 2-1 through the splicing structure according to a certain rule;

[0051] In an embodiment of the present invention, the first intermediate sub-module 2-1, the second peripheral sub-module 2-2, the third peripheral sub-module 2-3, the fourth peripheral sub-module 2-4, and the fifth peripheral sub-module 2-5 can also be fixed above the support frame 4 by bolts 7, making the expandable module assembly 2 more firm. Two mutually perpendicular hot runners 3 are provided in each of the first intermediate sub-module 2-1, the second peripheral sub-module 2-2, the third peripheral sub-module 2-3, the fourth peripheral sub-module 2-4, and the fifth peripheral sub-module 2-5, as Figure 4 shown;

[0052] In the completed expandable module assembly 2, the hot runners 3 are accurately docked with each other and run through the entire expandable module assembly 2 to ensure the molten state of the melt;

[0053] In an embodiment of the present invention, in industrial mass production, the number of sub-modules in the expandable module assembly 2 can be expanded according to the actual number of nozzles 5 used and the sub-modules can be spliced, as Figure 5 shown.

[0054] In an embodiment of the present invention, after the expandable module assembly 2 is spliced, the hot runners 3 in the outermost circle of the expandable module assembly 2 are firmly blocked with wooden plugs or rubber plugs to prevent the melt from flowing out. Finally, the nozzle 5 is tightened to the first intermediate sub-module 2-1, the second peripheral sub-module 2-2, the third peripheral sub-module 2-3, the fourth peripheral sub-module 2-4, and the fifth peripheral sub-module 2-5 through the sub-module fixing thread 8 on the nozzle 5, as Figure 4 shown. And the flow rate of each nozzle 5 can be adjusted by a thread adjuster 6.

[0055] In an embodiment of the present invention, the first intermediate sub-module 2-1, the second peripheral sub-module 2-2, the third peripheral sub-module 2-3, the fourth peripheral sub-module 2-4, and the fifth peripheral sub-module 2-5 all have different convex and concave splicing structures for splicing between the sub-modules, making it easier to position between the first intermediate sub-module 2-1, the second peripheral sub-module 2-2, the third peripheral sub-module 2-3, the fourth peripheral sub-module 2-4, and the fifth peripheral sub-module 2-5 and accurately docking the hot runners 3 between the first intermediate sub-module 2-1, the second peripheral sub-module 2-2, the third peripheral sub-module 2-3, the fourth peripheral sub-module 2-4, and the fifth peripheral sub-module 2-5. It can also effectively prevent the melt from leaking through the gaps between the first intermediate sub-module 2-1, the second peripheral sub-module 2-2, the third peripheral sub-module 2-3, the fourth peripheral sub-module 2-4, and the fifth peripheral sub-module 2-5. The hot runners 3 at the outermost periphery of the completed expandable module assembly 2 are blocked with wooden plugs or rubber plugs to make the melt fill the entire spliced hot runner 3.

[0056] In an embodiment of the present invention, as Figure 4As shown in the figure, the nozzle 5 is firmly fixed on the first intermediate sub-module 2-1, the second peripheral sub-module 2-2, the third peripheral sub-module 2-3, the fourth peripheral sub-module 2-4 and the fifth outer peripheral module 2-5 through the sub-module fixing thread 8. Thread regulators 6 are installed above the first intermediate sub-module 2-1, the second peripheral sub-module 2-2, the third peripheral sub-module 2-3, the fourth peripheral sub-module 2-4 and the fifth outer peripheral module 2-5. The thread regulators 6 are connected to the inside of the nozzle 5. By rotating the thread regulator 6 through the thread, the distance inside the nozzle 5 is adjusted to adjust the flow rate of each nozzle 5, so as to make each nozzle 5 produce ultrafine fibers with a uniform diameter.

[0057] The working principle of the present invention: Add polypropylene solid particles into the extruder 1. The extruder 1 is heated by a heating coil to melt and plasticize the polypropylene solid particles. The propeller in the extruder 1 rotates to extrude the melt. The melt enters the hot runner 3 of the expandable module assembly 2 from the inlet of the intermediate sub-module 2-1. With the continuous feeding of the extruder 1, the melt fills the entire hot runner 3. The melt flows into the nozzle 5 through the hot runner 3. Each nozzle 5 also has a heating coil to ensure the molten state of the melt. When the melt in the nozzle 5 reaches a certain level, turn on the high-voltage electrostatic generator. The receiving plate is connected to high voltage, and the support frame 4 is grounded. A high-voltage electrostatic field is generated between the receiving plate and the nozzle 5, making the nozzle 5 inductively charged to form a jet, so that the nozzle 5 generates fibers. Adjust the magnitude of the high-voltage electrostatic and adjust the flow rate of each nozzle 5 through the thread regulator 6, so that all nozzles 5 produce ultrafine fibers with a uniform diameter, thereby producing a fiber felt with a certain width.

[0058] Example 2

[0059] As Figure 5 shown, taking the 3×3 module as an example, the first intermediate sub-module 2-1 is fixed at the exact center position above the support frame 4;

[0060] The second peripheral sub-module 2-2 is spliced at two places above and below the first intermediate sub-module 2-1. The third peripheral sub-module 2-3 is spliced on the left and right sides of the first intermediate sub-module 2-1. The fourth peripheral sub-module 2-4 is spliced at two places in the lower right and upper left of the first intermediate sub-module 2-1. The fifth outer peripheral module 2-5 is spliced at two places in the lower left and upper right of the first intermediate sub-module 2-1. The expandable module assembly 2 is centrosymmetric with respect to the first intermediate sub-module 2-1. Example

[0061] In the embodiment of the present invention, the splicing of a larger-scale 5×5 module is carried out on the basis of the splicing of the 3×3 module. Example

[0062] In the embodiments of the present invention, the splicing of larger-scale modules such as 6×6 modules is based on the splicing of 3×3 modules.

[0063] In the above embodiments, the descriptions of the respective embodiments have their own focuses. For the parts not detailed or recorded in a certain embodiment, reference may be made to the relevant descriptions of other embodiments.

[0064] II. Application embodiments:

[0065] Application example

[0066] Applying the technology of the present invention to industrial production, compared with the original technology, it greatly exceeds the original technology in terms of both production efficiency and product quality. Especially during the process of replacing templates and maintenance, the process has changed from extremely complex in the past to extremely simple now, which not only saves time but also greatly reduces costs.

[0067] III. Evidence of the related effects of the embodiments:

[0068] Compared with the entire large module in the original technology, if the number of nozzles 5 needs to be changed in the original technical solution, the existing module has to be abandoned and a suitable large module has to be reprocessed, which requires a large amount of manpower and financial resources and also wastes a lot of time for processing the new module. However, the technology of the present invention does not require such cumbersome operations. It only needs to add or reduce modules on the original expandable module assembly 2 according to needs, which greatly saves the processing cost. In addition, the module is easy to install. Compared with traditional modules, if the nozzle 5 becomes blocked, the entire module has to be disassembled to solve the problem. In the technology of the present invention, each module is independent and can be freely disassembled, which is convenient for maintenance. In the original technology, since the module is a whole, the flow rate of the nozzle 5 cannot be accurately controlled, resulting in different fiber diameters and greatly reducing the product quality. In the technology of the present invention, the flow rate of each nozzle 5 can be accurately adjusted through the threaded regulator 6, so that each nozzle 5 produces ultra-fine fibers with the same diameter, improving the product quality while increasing the efficiency.

[0069] The above is only a relatively preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention by those skilled in the art within the technical scope disclosed by the present invention shall be covered by the protection scope of the present invention.

Claims

1. An expansion method for a modular melt electrospinning device of ultrafine fibers, characterized in that, The method includes: Fixing a first intermediate sub-module (2-1) with horizontal and vertical hot runners (3) inside to a support frame (4), and then sequentially combining and splicing a plurality of sub-modules with the same structure as the first intermediate sub-module (2-1) into an expandable module assembly (2). The number of sub-modules in the expandable module assembly (2) can be increased or decreased according to actual needs during industrial production to meet requirements; each sub-module is equipped with a thread adjuster (6), and the melt flow rate inside the nozzle (5) connected to the sub-module is adjusted by thread rotation, so that each nozzle (5) generates ultrafine fibers with the actually required diameter. Splicing structures are provided on each of the sub-modules for seamless splicing between the sub-modules; the splicing structures include matching protrusions and depressions, which are located on different sides of the sub-modules respectively. The hot runner (3) opened inside each sub-module is docked with the horizontal hot runner (3) of the adjacent sub-module. After the expandable module assembly (2) is spliced, the hot runners (3) in the outermost circle of the expandable module assembly (2) are blocked with wooden plugs or rubber plugs, so that the melt flows inside the expandable module assembly (2) and the melt outflow is prevented. The extruder (1) is heated by a heating coil, and each nozzle (5) also has a heating coil.

2. An ultrafine fiber modular melt electrospinning device implementing the extended method of the ultrafine fiber modular melt electrospinning device described in claim 1, comprising: The extruder (1) and the support frame (4) fixed on the working platform are characterized in that the support frame (4) is fixed with an expandable module assembly (2) by bolts (7), and the melt inlet of the expandable module assembly (2) is connected to the extruder (1); the expandable module assembly (2) is connected with a nozzle (5) through a sub-module fixing thread (8), and the nozzle (5) is communicated with a thread adjuster (6) installed on the expandable module assembly (2). The thread adjuster (6) is used to adjust the flow rate of the melt inside the nozzle (5), so that each nozzle (5) generates ultrafine fibers with the actually required diameter.

3. The modular melt electrospinning device for ultrafine fibers according to claim 2, wherein, The expandable module assembly (2) is freely combined and spliced by a plurality of sub-modules with horizontal and vertical hot runners (3) opened inside. The sub-modules include a first intermediate sub-module (2-1), a second peripheral sub-module (2-2), a third peripheral sub-module (2-3), a fourth peripheral sub-module (2-4) and a fifth peripheral sub-module (2-5). The first intermediate sub-module (2-1) is fixed at the exact center position above the support frame (4) by bolts (7), and the melt inlet is above the first intermediate sub-module (2-1), which is connected to the extruder (1). The second peripheral sub-module (2-2), the third peripheral sub-module (2-3), the fourth peripheral sub-module (2-4) and the fifth peripheral sub-module (2-5) are spliced onto the first intermediate sub-module (2-1) through the splicing structure.

4. The modular melt electrospinning device for ultrafine fibers according to claim 3, characterized in that, The first intermediate sub-module (2-1), the second peripheral sub-module (2-2), the third peripheral sub-module (2-3), the fourth peripheral sub-module (2-4) and the fifth peripheral sub-module (2-5) are all fixed above the support frame (4) by bolts (7).

5. A 3×3 modular melt electrospinning device expanded by the expansion method of the modular melt electrospinning device using the ultrafine fibers described in claim 1.

6. A 6×6 modular melt electrospinning device expanded by the expansion method of the modular melt electrospinning device using the ultrafine fibers described in claim 1.

7. Application of the expansion method of the modular melt electrospinning device using the ultrafine fibers described in claim 1 in the preparation of nanofibers for air filtration, liquid filtration, energy / battery separator, biomedicine, and sound absorption materials.

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