KR102637992B1 - Electrospinning module for manufacturing isotropic nanofiberous membrane and method of manufacturing isotropic nanofiberous membrane thereby - Google Patents

Abstract

The electrospinning module for producing an isotropic nanofiber membrane of the present invention includes (i) a connecting rod (R) in the form of a hollow tube extending along the horizontal direction from the rotation axis so that two or more unit electrospinning tubes (T) are located on the same plane. It is installed at each of the distal ends, and (ii) the longitudinal direction of the unit electrospinning tube (T) and the extension direction of the connecting rod (R) to which the unit electrospinning tube (T) is connected form an intersection angle (α). Unit electrospinning tubes (T) are formed to extend along a direction that does not form a straight line with the extension direction of the connecting rod (R), (iii) from the spinning solution supply pipe (P) at the center of the electrospinning module (M) A spinning solution inlet hole through which the spinning solution flows is formed, and (iv) the unit electrospinning tube (T) is in the form of a rectangular hollow tube with an empty interior except for the end portions on both sides, but the end portions on both sides are branched into two or more. As a result, two or more sharp edge portions (A) are formed at each end of both sides, and the lower portion (n1) of each of the sharp edge portions (A) is a shape selected from cylindrical and polygonal, and the upper portion (n2) is the lower portion (n1). ) is characterized in that a radiating hole (n) in the form of a cut half is formed adjacent to the outer line of the sharp corner portion (A).
The pinwheel-type electrospinning module of the present invention can produce nanofibers with good flexibility, and the nanofiber orientation direction in the nanofiber membrane can be easily controlled.
The isotropic nanofiber membrane manufactured by the present invention has curved nanofibers integrated in multiple layers, so the physical entanglement between nanofibers is good, so it has excellent mechanical properties, and the orientation angle with respect to the fiber axis direction is easily adjusted, making it isotropic. great.
Therefore, the isotropic nanofiber membrane manufactured by the present invention is useful as a membrane for secondary batteries.
In addition, the present invention is useful for manufacturing carbon nanofiber membranes that have excellent flexibility, do not break easily, and have excellent tensile strength.

Description

Electrospinning module for manufacturing isotropic nanofiber membrane and method of manufacturing isotropic nanofiber membrane using the same {Electrospinning module for manufacturing isotropic nanofiberous membrane and method of manufacturing isotropic nanofiberous membrane thereby}

The present invention relates to an electrospinning module for manufacturing an isotropic nanofiber membrane and a method for manufacturing an isotropic nanofiber membrane using the same. More specifically, it is composed of curved nanofibers, so that physical entanglement between nanofibers increases and the fiber axis direction increases. It is easy to control the orientation angle of the nanofibers, making it possible to manufacture isotropic nanofiber membranes with excellent isotropy and mechanical properties. In particular, it is possible to manufacture isotropic nanofiber membranes that can greatly improve flexibility and tensile strength when manufacturing carbon nanofiber membranes. It relates to a spinning module and a method of manufacturing an isotropic nanofiber membrane using the same.

In conventional electrospinning devices, spinning nozzles or spinning tubes have been widely used as devices for electrospinning a spinning solution.

Specifically, Korean Patent No. 10-1172267 relates to an electrospinning device that includes a polygonal tube inside instead of a spinning nozzle, and relates to electrospinning using both electrostatic force and centrifugal force.

As another prior art, Korean Patent No. 10-1263296 relates to an electrospinning device including a cylindrical spinning tube with a hollow portion having a polygonal cross-section inside, and relates to electrospinning by rotating the polygonal cylindrical tube.

As another prior art, Korean Patent No. 10-1291592 relates to an electrospinning device including a conical spinning tube with a hollow portion having a polygonal cross-section inside, and relates to electrospinning by rotating the polygonal conical tube.

Since the nanofibers electrospun with the conventional electrospinning devices have a straight shape rather than a curved shape, the phenomenon of physically entangling each other within the manufactured nanofiber membrane does not occur smoothly, and the mechanical properties of the nanofiber membrane deteriorate, and the carbon When manufacturing nanofiber membranes, their flexibility was low and they broke easily, which limited their industrial use.

In addition, the nanofibers electrospun with the conventional electrospinning devices were difficult to provide isotropy within the nanofiber membrane and difficult to control orientation, so their mechanical properties were poor and their applications were limited.

The object of the present invention is to provide an electrospinning module capable of producing curved nanofibers with excellent flexibility.

Another task of the present invention is to provide an electrospinning module in which the isotropy of the nanofibers in the nanofiber membrane is excellent and the orientation can be easily adjusted when manufacturing the nanofiber membrane.

Another task of the present invention is to provide a method of manufacturing an isotropic nanofiber membrane in which curved nanofibers are integrated with good isotropy and has excellent mechanical properties, making it useful as a separator for secondary batteries.

Another task of the present invention is to provide a method of manufacturing a carbon nanofiber membrane composed of curved carbon nanofibers, which has excellent flexibility, does not easily break, and has excellent tensile strength.

In order to achieve this task, in the present invention, (i) the end portion of a connecting rod (R) in the form of a hollow tube extending along the horizontal direction from the rotation axis so that two or more unit electrospinning tubes (T) are located on the same plane. It is installed in each, and (ii) the longitudinal direction of the unit electrospinning tube (T) and the extension direction of the connecting rod (R) to which the unit electrospinning tube (T) is connected form an intersection angle (α), so that the unit Electrospinning tubes (T) are formed to extend along a direction that does not form a straight line with the extension direction of the connecting rod (R), and (iii) are separated from the spinning solution supply pipe (P) in the center of the electrospinning module (M). A spinning solution inlet hole is formed through which the solution flows, and (iv) the unit electrospinning tube (T) is in the form of a rectangular hollow tube with an empty interior except for the end portions on both sides, but the end portions on both sides are branched into two or more. Two or more sharp edge parts (A) are formed at each end of both ends, and the lower part (n1) of each of the sharp edge parts (A) is a shape selected from cylindrical and polygonal, and the upper part (n2) is the lower part (n1). A nanofiber membrane is manufactured using an electrospinning module for producing an isotropic nanofiber membrane in which a spinning hole (n) in the form of a half-cut portion is formed adjacent to the outer line of the sharp edge portion (A).

The isotropic nanofiber membrane manufactured by the present invention has curved nanofibers integrated in multiple layers, so the physical entanglement between nanofibers is good, so it has excellent mechanical properties, and the orientation angle with respect to the fiber axis direction is easily adjusted, making it isotropic. great.

In addition, the present invention makes it possible to manufacture an isotropic nanofiber membrane that has no difference in physical properties depending on the very precise direction of the nanofiber membrane and allows control of various properties, including pores, according to the directionality. This completely isotropic physical property control has the characteristic of enabling uniform physical properties according to direction due to the bendability of the manufactured nanofibers.

In the case of linear nanofibers generated from conventional electrospinning, etc., the orientation angle of the nanofibers in a direction perpendicular to the machine direction of the collector may occur depending on the direction, making it difficult to control various properties such as perfectly isotropic mechanical properties or pores.

Therefore, the nanofiber membrane produced by the present invention is useful as a membrane for secondary batteries.

In addition, the present invention is useful for manufacturing carbon nanofiber membranes that have excellent flexibility, do not break easily, and have excellent tensile strength.

The present invention covers the field of water treatment using superabsorbency/superhydrophobicity, superabsorption/superoil affinity, etc., as well as cathodes, anodes, and electrolytes such as air purification filters, sensors capable of two or more types of sensing, all-solid batteries, and all-solid supercapacitors. It can be used very widely, including energy storage systems and various catalysts.

Figure 1 is a schematic diagram of a process for producing an isotropic nanofiber membrane by electrospinning nanofibers (F) from the electrospinning module of the present invention with an intersection angle (α) of 90°.
Figure 2 is an enlarged schematic diagram of the edge portions (A) of both ends of the unit electrospinning tube (T) of the present invention.
Figure 3 is a perspective schematic diagram of an example of a radiation hole (n) formed in each of the edge portions (A) of both end portions of the unit electrospinning tube (T) of the present invention.
Figure 4 is a scanning electron microscope photograph of the isotropic nanofiber membrane prepared in Example 1.
Figure 5 is an enlarged scanning electron microscope photograph of Figure 4.
Figure 6 is a stress-strain correlation graph of the isotropic nanofiber membrane prepared in Example 1.

Hereinafter, the present invention will be described in detail through the attached drawings.

As shown in FIG. 1, the pinwheel-type electrospinning module according to the present invention includes a connecting rod (R) in the form of a hollow tube extending horizontally from the rotation axis so that two or more unit electrospinning tubes (T) are located on the same plane. It is provided with a structure installed at each end of the.

As shown in Figure 1, since the longitudinal direction of the unit electrospinning tube (T) and the extension direction of the connecting rod (R) to which the unit electrospinning tube (T) is connected form an intersection angle (α), the unit electrospinning tube (T) The radiating tubes (T) are formed to extend along a direction that is not in a straight line with the extending direction of the connecting rod (R).

In addition, a spinning solution inlet hole through which the spinning solution flows from the spinning solution supply pipe (P) is formed in the center of the electrospinning module (M).

The intersection angle (α) formed by the longitudinal direction of the unit electrospinning tube (T) and the extending direction of the connecting rod (R) to which the unit electrospinning tube (T) is connected is 1 to 179° or 181 to 359°.

An example of a form in which the longitudinal direction of the unit electrospinning tube (T) and the extending direction of the connecting rod (R) to which the unit electrospinning tube (T) is connected intersect, " "brother, " “Including my brother, etc.

The intersection angles (α) formed by the longitudinal direction of the unit electrospinning tubes (T) constituting the electrospinning module (M) and the extension direction of the connecting rod (R) to which the unit electrospinning tubes (T) are connected are the same. It may be possible, or it may be different from each other.

As shown in FIG. 2, the unit electrospun tube (T) is in the form of a square tube except for the end portions on both sides, but the end portions on both sides are branched into two or more and there are two or more sharp edge portions (A) on each end portion on both sides. A radiating hole (n) is formed in each of the sharp corner portions (A), wherein the lower end (n1) is in a shape selected from cylindrical and polygonal, and the upper end (n2) is in the form of a half of the lower end (n1) being cut. It has a structure formed adjacent to the outer line of the sharp edge portion (A).

Meanwhile, the height (h) of the upper end of the radiation hole (n2) of each unit electrospinning tube (T) constituting the electrospinning module (M) may be the same, or, more preferably, may be different from each other.

If the height (h) of the upper part of the spinning hole is different from each other, a nanofiber membrane can be composed of curved nanofibers with different orientation angles with respect to the fiber axis direction, and this can achieve the desired mechanical properties of the nanofiber membrane. It becomes possible.

In the present invention, the nanofibers produced by appropriately controlling the rotation direction and rotation speed of each unit electrospinning tube (T) are formed in a curved shape to increase entanglement between nanofibers and control the orientation angle of the nanofibers. The mechanical strength of nanofiber membranes can be improved.

The bendability of the radiated nanofibers, that is, the curved shape of the nanofibers, is appropriately adjusted according to the height (h) of the upper part (n2) of the spinning hole. Specifically, the straightness of the spinning solution stream electrospun from the spinning hole (n) is disturbed by the height (h) of the upper part (n2) of the spinning hole, so that nanofibers in a curved shape rather than a straight shape are manufactured.

Since the height (h) of the upper part of the spinning hole (n2) is open, the straight stream formed during the electrospinning process is formed early, and the centrifugal force of the rotating unit electrospinning tube (T) acts to create curved nanofibers. This is because mutual entanglement between the formed nanofibers is strong.

If the upper half of the spinning hole (n2), in which half of the lower part of the spinning hole (n1) is open, is not formed, that is, if the height (h) is 0, the spun nanofibers are not formed in a curved shape, but are manufactured in a straight shape. , the entanglement phenomenon between nanofibers is also significantly reduced. This is because the mutual interference of linear streams during the electrospinning process is reduced, so when the formed nanofibers are integrated into the collector, the straightness of the nanofibers is maintained and integrated into the collector.

The electrospinning module for producing isotropic nanofiber membranes of the present invention specifically manufactures carbon nanofiber membranes using polyacrylonitrile or polyamic acid, which are raw materials for carbon nanofibers, through a stabilization process or an imide process followed by a carbonization process. In order to provide flexibility, it is very important that the shape of nanofibers such as polyacrylonitrile or polyamic acid is curved rather than straight nanofibers. This is a very useful shape that can be controlled without a separate post-process. It is an electrospinning system.

Next, we will look at a method of manufacturing a nanofiber membrane in which nanofibers with excellent flexibility are integrated using the pinwheel-type electrospinning module of the present invention.

The method of manufacturing a nanofiber membrane according to the present invention uses a high voltage generator (HV) to each of the electrospinning module for manufacturing the isotropic nanofiber membrane of the present invention and the collector (C) located on the electrospinning module for manufacturing the isotropic nanofiber membrane. While applying voltage, supply the spinning solution to each unit electrospinning tube (T) through the spinning solution inlet hole formed in the center of the electrospinning module (M) for producing the isotropic nanofiber membrane, and then electrospinning using a rotating device. The module (M) is rotated in either clockwise or counterclockwise direction to electrospun nanofibers (F) in the direction of the collector (C) through the spinning hole (n).

In the present invention, since the electrospinning module (M) rotates, it is easy to control the orientation angle of the nanofibers along the nanofiber axis direction and improves the entanglement phenomenon between nanofibers.

As an example of implementation of the present invention, two or more electrospinning modules (M) for manufacturing isotropic nanofiber membranes according to the present invention can be installed under one collector (C), and in this case, two or more pinwheel-type electrospinning modules Among the (M), the electrospinning modules (M) for producing isotropic nanofiber membranes installed in odd numbers based on one side of the collector (C) are rotated in either clockwise or counterclockwise direction and are arranged in overlapping even numbers. The electrospinning modules (M) for manufacturing nanofiber membranes can easily adjust the orientation angle of the nanofibers along the nanofiber axis direction by rotating them in either clockwise or counterclockwise direction and prevent entanglement between nanofibers. It is desirable to improve the mechanical properties of the nanofiber membrane by improving the phenomenon.

In addition, spinning solutions of different polymers may be supplied to each of the unit electrospinning tubes (T) constituting the electrospinning module (M) for producing an isotropic nanofiber membrane, or spinning solutions of the same polymer may be supplied to each other.

In addition, in the present invention, the nanofibers spun by moving the electrospinning module (M) for producing an isotropic nanofiber membrane back, forth, left, and right are randomly arranged on the collector, so that there is no difference between the width direction mechanical properties and the longitudinal mechanical properties of the nanofiber membrane. Nanofiber membranes can also be manufactured.

The present invention relates to the manufacture of a carbon nanofiber membrane with excellent flexibility, resistance to brittleness, and excellent tensile strength when the precursor carbonizes a nanofiber membrane composed of polyacrylonitrile or polyamic acid, which are raw materials for carbon nanofibers, at high temperature. becomes possible.

The present invention manufactures a nanofiber membrane by supplying a spinning solution of a polymer containing an inorganic material to each of the unit electrospinning tubes (T) constituting the electrospinning module (M) for producing an isotropic nanofiber membrane, and then produces a nanofiber membrane. A nanofiber membrane composed only of inorganic nanofibers can be manufactured by heat treating at high temperature.

Hereinafter, the present invention will be examined in more detail through examples.

Example 1

Polyamic acid was dissolved in dimethylformamide to prepare a spinning solution with a solid content of 15% by weight.

Next, using a high voltage generator (HV), four unit electrospinning tubes (T) are attached to each end of the connecting rod (R) extending horizontally from the rotation axis at an intersection angle (α) of 90° as shown in Figure 1. A voltage of 35 kV is applied to each of the electrospinning module (M) for manufacturing the isotropic nanofiber membrane according to the present invention, which is installed as After supplying the spinning solution to each unit electrospinning tube (T) at a supply rate of 1.5 cc/min through the spinning solution inlet hole formed in the center of the electrospinning module (M) for producing the isotropic nanofiber membrane, the isotropic A nanofiber membrane was manufactured by electrospinning while rotating the electrospinning module (M) clockwise at a rotation speed of 1,000 rpm.

At this time, the unit electrospinning tube (T) has the overall shape of a square hollow tube, but the end portions on both sides are branched into two, and two sharp edge portions (A) are formed on each of the two end portions, and each of the sharp edge portions (A) has a lower end ( n1) is a cylindrical shape with a diameter of 0.8 mm, the upper part (n2) has a height (h) of 5.0 mm, and the radial hole (n), which is a semi-cylindrical shape with half of the cylindrical shape at the lower part (n1) cut, is sharp at the corner (A). A unit electrospinning tube (T) with a total length of 120 mm formed adjacent to the outline of was used.

The scanning electron microscope image of the polyamic acid isotropic nanofiber membrane prepared as above was shown in Figure 4, and the scanning electron microscope image taken by enlarging Figure 4 was shown in Figure 5.

The results of measuring the stress-strain correlation graph in the longitudinal and transverse machine directions (direction perpendicular to the machine direction) of the polyamic acid isotropic nanofiber membrane prepared as above are shown in Figure 6. As can be seen in Figure 6, the polyamic acid isotropic nanofiber membrane prepared in Example 1 clearly shows that it is an isotropic sample. This isotropy of tensile strength is a very important characteristic in industrial applications where the effect depending on direction is shown when applied to filters and secondary battery separators.

A: Sharp edges formed at both ends of the unit electrospinning tube (T)
C: Collector HV: High voltage generator
T: Unit electrospinning tube M: Nanofiber membrane
F: Nanofiber P: Spinning solution supply pipe
R: connecting rod n: radiating hole
n1: lower part of radiating hole n2: upper part of radiating hole
h: Height of the upper part of the radiation hole (n2)
X: Longitudinal (machine direction) stress-strain correlation graph of the isotropic nanofiber membrane prepared in Example 1
Y: Transverse direction (direction perpendicular to the machine direction) stress-strain correlation graph of the isotropic nanofiber membrane prepared in Example 1

Claims (13)

(i) Two or more unit electrospinning tubes (T) are installed at each end of a connecting rod (R) in the form of a hollow tube extending in the horizontal direction from the rotation axis so that it is located on the same plane, and (ii) the unit The longitudinal direction of the electrospinning tube (T) and the extension direction of the connecting rod (R) to which the unit electrospinning tube (T) is connected form an intersection angle (α), so that the unit electrospinning tube (T) is connected to the connecting rod ( It is formed to extend along a direction that does not form a straight line with the direction of extension of R), and (iii) a spinning solution inflow hole is formed in the center of the electrospinning module (M) through which the spinning solution flows from the spinning solution supply pipe (P). (iv) The unit electrospun tube (T) is in the form of a rectangular hollow tube with an empty interior except for the end portions on both sides, but the end portions on both sides are branched into two or more and there are two or more sharp corners on each end portion on both sides ( A) are formed, and in each of the sharp corner portions (A), the lower part (n1) is a shape selected from cylindrical and polygonal, and the upper part (n2) is a radiating hole ( Electrospinning module for producing an isotropic nanofiber membrane, characterized in that n) is formed adjacent to the outer line of the sharp edge portion (A). The method of claim 1, wherein the intersection angle (α) formed between the longitudinal direction of the unit electrospinning tube (T) and the extending direction of the connecting rod (R) to which the unit electrospinning tube (T) is connected is 1 to 179°. Electrospinning module for manufacturing isotropic nanofiber membranes. The method of claim 1, wherein the intersection angle (α) formed between the longitudinal direction of the unit electrospinning tube (T) and the extending direction of the connecting rod (R) to which the unit electrospinning tube (T) is connected is 181 to 359°. Electrospinning module for manufacturing isotropic nanofiber membranes. The method of claim 1, wherein the intersection angle formed by the longitudinal direction of the unit electrospinning tubes (T) constituting the electrospinning module (M) and the extension direction of the connecting rod (R) to which the unit electrospinning tubes (T) are connected ( α) Electrospinning module for manufacturing an isotropic nanofiber membrane, characterized in that the elements are identical to each other. The method of claim 1, wherein the intersection angle formed by the longitudinal direction of the unit electrospinning tubes (T) constituting the electrospinning module (M) and the extension direction of the connecting rod (R) to which the unit electrospinning tubes (T) are connected ( α) Isotropic nanofibers, characterized in that the intersection angles (α) formed by the longitudinal direction of the unit electrospinning tubes (T) and the extending direction of the connecting rod (R) to which the unit electrospinning tubes (T) are connected are different. Electrospinning module for membrane manufacturing. The method of claim 1, wherein the height (h) of the upper end of the spinning hole (n2) of each of the unit electrospinning tubes (T) constituting the electrospinning module (M) is the same as each other. Electrospinning for producing an isotropic nanofiber membrane. module. The method of claim 1, wherein the height (h) of the upper end of the spinning hole (n2) of each of the unit electrospinning tubes (T) constituting the electrospinning module (M) is different from each other. module. Using a high voltage generator (HV), apply voltage to each of the electrospinning module for manufacturing the isotropic nanofiber membrane of claim 1 and the collector (C) located on the electrospinning module (M) for manufacturing the isotropic nanofiber membrane, After supplying the spinning solution to each unit electrospinning tube (T) through the spinning solution inlet hole formed in the center of the electrospinning module for membrane production, the electrospinning module (M) is rotated clockwise and counterclockwise using a rotary device. A method of manufacturing an isotropic nanofiber membrane, characterized in that the nanofibers (F) are electrospun in the collector (C) direction through the spinning hole (n) by rotating in one of the directions. The method of claim 8, wherein two or more electrospinning modules (M) for producing isotropic nanofiber membranes are installed under the collector (C). According to claim 9, among the two or more electrospinning modules (M) for isotropic nanofiber membrane production, the electrospinning modules (M) for isotropic nanofiber membrane production installed in odd numbers based on one side of the collector (C) are rotated clockwise and An isotropic nanofiber membrane characterized in that it is rotated in one of the counterclockwise directions, and the electrospinning modules (M) for producing isotropic nanofiber membranes installed in even numbers are rotated in either the other direction of clockwise or counterclockwise. Manufacturing method. The method of claim 8, wherein spinning solutions of different polymers are supplied to each unit electrospinning tube (T) constituting the electrospinning module (M) for producing an isotropic nanofiber membrane. The method of claim 8, wherein a nanofiber membrane is manufactured by supplying a spinning solution of a polymer containing an inorganic substance to each of the unit electrospinning tubes (T) constituting the electrospinning module (M) for producing an isotropic nanofiber membrane, and then manufacturing the nanofiber membrane. A method of producing an isotropic nanofiber membrane, characterized in that the nanofiber membrane is heat-treated at a high temperature so that it consists only of inorganic nanofibers. The method of claim 8, wherein the electrospinning module (M) for producing the isotropic nanofiber membrane is moved forward, left, right, and left to randomly arrange the spun nanofibers on the collector (C).