Fiber production system and method of producing fibers using the same

Abstract

The application discloses a fiber preparation system and a method for preparing fibers by using the fiber system. The fiber preparation system comprises a feeding device, a container and a flow guide set. The feeding device comprises a moving part and the container. The container is used for containing fiber stock solution. The container is provided with a liquid outlet. The moving part can move relative to the container to reduce the volume of the container, so that the fiber stock solution flows out of the liquid outlet. The flow guide set is in sealed connection with the feeding device. The flow guide set is provided with an air inlet and an air outlet. The liquid outlet extends into the inside of the air outlet or extends out of the air outlet to the outside of the flow guide set to form a single fiber. The fiber collecting device is used for collecting the single fiber. The fiber stock solution provided by the feeding device can form a single fiber under the traction of the airflow and be collected by the fiber collecting device. The continuous production is realized under the driving of the fiber collecting device.

Description

Technical Field

[0001] This invention relates to the field of fiber material preparation technology, and in particular to a fiber preparation system and a method for preparing fibers using the fiber system. Background Technology

[0002] Microfibers, with their submicron or nanometer-scale diameters and high aspect ratios, exhibit unique physical and mechanical properties not found in ordinary bulk or thin-film materials, such as ultra-high strength, flexibility, and electrical properties. As a dielectric polymer material, PVDF (polyvinylidene fluoride)-based microfibers not only possess excellent mechanical properties but also rich piezoelectric, dielectric, and pyroelectric properties, thus they have been widely studied and applied in the field of flexible electronics. With further research, scientists believe that directionally arranged PVDF-based fibers will undoubtedly be endowed with even more unique properties on top of their existing functions.

[0003] Currently, the methods for preparing PVDF-based microfibers include electrospinning, air spinning, and melt-blown spinning. However, the fibers prepared by these methods are all in a random arrangement and cannot be strictly oriented, which limits the further research and application of PVDF-based fibers. Summary of the Invention

[0004] The present invention aims to at least solve one of the technical problems existing in the prior art. To this end, the present invention proposes a fiber preparation system that can produce oriented fibers.

[0005] The present invention also proposes a method for preparing fibers using this fiber system.

[0006] In a first aspect, one embodiment of the present invention provides a fiber preparation system, comprising:

[0007] A feeding device includes a moving part and a container. The container has a receiving cavity for containing fiber solution. The container is provided with a liquid outlet. The moving part is movable relative to the container so that the fiber solution flows out from the liquid outlet.

[0008] A flow guide kit is sealed to the feeding device. The flow guide kit is provided with an air inlet and an air outlet. The liquid outlet extends into the interior of the air outlet or extends from the air outlet to the exterior of the flow guide kit to guide a single fiber.

[0009] A fiber collecting device for collecting the single fiber.

[0010] The fiber preparation system of this invention has at least the following beneficial effects: In this invention, the relative movement of the moving parts and the container in the feeding device allows the fiber raw liquid to flow out from the outlet. The fiber raw liquid after flowing out can be stretched into a directional ray-shaped liquid flow under the traction of the airflow. The solvent in the single liquid flow that is pulled out evaporates, and the liquid flow solidifies to form a directional single fiber. The formed single fiber is collected by the fiber collecting device, and continuous production is achieved under the drive of the fiber collecting device.

[0011] According to other embodiments of the fiber preparation system of the present invention, the fiber collecting device includes a drive motor and a drum, the drive motor being used to drive the drum to rotate. The drive motor is mechanically connected to the drum in the axial direction. The fiber collecting device is mainly used for single fibers generated by winding, and provides power through the traction of the drum's rotational torque to continuously generate single fibers, ultimately achieving continuous directional collection of single fibers. The drum serves two purposes: firstly, to utilize torque to continuously produce single fibers; and secondly, to achieve strictly directional winding and equidistant collection of fibers on the drum. When using a first drive device such as a reciprocating machine, the fiber spacing d can be controlled by adjusting the first drive device, its operating speed V (mm / min), and the drum's rotational speed w (rad / min), satisfying the following relationship:

[0012] In some embodiments, the speed of the drive motor is 0 to 1000 rad / min, the diameter of the roller is 10 mm, and the width is 31.4 mm.

[0013] According to other embodiments of the fiber preparation system of the present invention, a coating is provided on the roller; preferably, the coating is any one of writing paper, aluminum foil, or polymer film. Using the coating as a substrate, the coating is detachably mounted on the roller and can be removed together with the fibers after fiber collection. The coating can then be used as part of the fibers as a consumable.

[0014] According to other embodiments of the fiber preparation system of the present invention, the fiber preparation system further includes a first driving device for driving the feeding device to perform unidirectional or reciprocating motion, the direction of which is perpendicular to the liquid outlet direction. The fiber solution is discharged along the liquid outlet direction and drawn by the airflow, then solidified to form oriented single fibers. The first driving device drives the feeding device to move perpendicular to the liquid outlet direction, thereby continuously generating single fibers that can be spaced and arranged on the fiber collecting device.

[0015] In some embodiments, the first driving device is a reciprocating machine. The reciprocating machine is a drive capable of linear reciprocating motion, has a connecting rod, and can perform reciprocating motion under the drive of a motor. In use, the feeding device is fixed to the connecting rod of the reciprocating machine, and moves with the reciprocating machine. The fixing method can be a mechanical rigid connection such as welding or screw fixing, or a detachable connection.

[0016] According to other embodiments of the fiber preparation system of the present invention, the feeding device further includes a second driving device for driving the moving component to move. The second driving device enables quantitative and stable driving of the moving component, thereby allowing precise control of the fiber solution flow rate.

[0017] In some embodiments, the second driving device is an injection pump. In some embodiments, the feeding device includes an injection pump and a syringe, wherein the structure formed by the piston and piston shaft of the syringe is equivalent to a moving part, and the needle of the syringe is equivalent to a liquid outlet. The injection pump can drive the syringe to quantitatively and stably provide the fiber solution.

[0018] In some embodiments, the flow guiding kit is cylindrical, the feeding device is a syringe, and the flow guiding kit is coaxial with the feeding device.

[0019] According to other embodiments of the fiber preparation system of the present invention, the distance between the end face of the liquid outlet and the end face of the air outlet is 0 mm to 10 mm. When the distance is 0 mm, it means that the liquid outlet extends into the interior of the air outlet. When the distance is greater than 0, it means that the liquid outlet extends out of the air outlet and is located outside the flow guide kit.

[0020] According to other embodiments of the fiber preparation system of the present invention, the liquid outlet direction is the same as the gas outlet direction. The liquid outlet direction and the gas outlet direction are aligned without any angle, resulting in straight, bend-free fibers that are oriented in the fiber collecting device.

[0021] In some embodiments of the fiber preparation system according to the present invention, the air inlet and the air outlet have the same cross-sectional area. The air inlet and air outlet are configured to have the same cross-sectional area. In some embodiments, both the air inlet and the air outlet are circular and have the same size, with the diameter of the air inlet being 1 mm to 5 mm and the diameter of the air outlet being 1 mm to 5 mm.

[0022] According to other embodiments of the fiber preparation system of the present invention, the air inlet direction is perpendicular to the air outlet direction, which facilitates ventilation operation.

[0023] According to other embodiments of the fiber preparation system of the present invention, the fiber preparation system further includes a gas supply device for introducing gas into the air inlet.

[0024] According to other embodiments of the fiber preparation system of the present invention, the gas supply device is any one of a vortex fan, a centrifugal fan, an air compressor, and a high-pressure gas cylinder. The gas provided by the present invention can be a flowing gas stream, and is not limited to compressed air. The types of gas provided include, but are not limited to, one or more of air, nitrogen, argon, and oxygen.

[0025] Secondly, an embodiment of the present invention provides a method for preparing fibers using the above-described fiber preparation system, comprising the following steps:

[0026] Add fiber solution to the receiving cavity, and move the moving part to make the fiber solution flow out from the outlet.

[0027] Start the air supply device and introduce a starting airflow into the air inlet to draw the fiber solution into a single fiber;

[0028] The fiber collecting device is activated. After the fiber collecting device collects the single fiber, an auxiliary airflow is introduced into the air inlet or the airflow is shut off. The flow rate of the auxiliary airflow is less than the flow rate of the activating airflow. In this embodiment of the invention, the activating airflow pulls the fiber solution to produce a single fiber. After the single fiber is produced, the fiber collecting device pulls the single fiber to complete continuous fiber production. For example, in some embodiments, the rotational torque of the roller is used to complete subsequent continuous production. According to other embodiments of the invention, the flow rate of the activating airflow is 1 SLPM to 10 SLPM. The fiber solution flowing out of the outlet is stretched into a ray-shaped liquid stream under the traction of the activating airflow, moving forward to the fiber collecting device for collection. The flow rate of the activating airflow is determined based on factors such as the viscosity and surface tension of the fiber solution. The purpose is to pull the fiber solution into a single filament under the traction of the activating airflow. The required activating airflow is adjusted according to different fiber solutions. The reason for setting the auxiliary airflow rate to be less than the starting airflow rate is that the starting airflow needs to overcome the surface tension and viscosity of the fiber solution to pull out a single fiber, while the auxiliary airflow only assists in the continuous traction and pulling out of a single fiber. When the fiber collecting device can provide forward power for the fiber, such as when the fiber collecting device has a roller, the main forward power of the fiber is provided by the roller torque. The role of the auxiliary airflow is only to assist in traction and stretching and to assist in solvent evaporation. The flow rate of the auxiliary airflow should be less than the starting airflow rate, or it can be directly set to 0 SLPM (i.e., the airflow is off). After a single fiber is formed, the single liquid stream pulled at the outlet is rapidly evaporated by the solvent under the action of the fiber collecting device and the auxiliary airflow, and the liquid stream solidifies into a fiber.

[0029] According to other embodiments of the present invention, the fiber preparation system includes a first driving device that drives the feeding device to move. The first driving device operates at a speed of 1 mm / min to 100 mm / min, and the feeding device supplies the fiber solution at a rate of 0.1 μL / min to 100 μL / min. In some embodiments, the maximum stroke of the first driving device is 40 cm. According to other embodiments of the present invention, the method further includes the steps of: stacking and hot-pressing the fibers collected on the fiber collecting device, wherein the angle between the extension directions of different layers of fibers during the stacking process is 1° to 90°. In some embodiments, the hot-pressing temperature is 150°C to 200°C.

[0030] According to other embodiments of the present invention, the fiber solution comprises PVDF and a solvent. The fiber solution can be a PDVF solution or a PDVF-based dispersion suspension formed by adding nanoparticles to a PDVF solution. By controlling the molecular weight and content of the PVDF powder, the fiber solution has a certain surface tension and viscosity, thereby exhibiting the characteristic of being stretchable into fibers.

[0031] In some embodiments, the fiber solution further includes at least one of barium titanate, zinc oxide, silicon oxide, iron oxide, silver, and zirconium oxide. That is, nanoparticles such as barium titanate, zinc oxide, silicon oxide, iron oxide, silver, and zirconium oxide can be added to the PDVF solution, with the solid content of the nanoparticles ranging from 5 wt% to 30 wt%. The solvent used in the fiber solution includes one or more mixtures of DMF, DMAC, NMP, DMSO, and acetone. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the fiber preparation system of the first embodiment;

[0033] Figure 2 A schematic diagram showing the liquid outlet extending into the air outlet;

[0034] Figure 3 This is a schematic diagram of the fiber preparation system of the second embodiment;

[0035] Figure 4 This is a schematic diagram of the preparation process of PVDF mono-oriented fibers in Example 2;

[0036] Figure 5 This is a schematic diagram of gas-assisted startup of a single fiber in Example 2;

[0037] Figure 6 This is a microscopic morphology diagram of the PVDF mono-oriented fibers in Example 2;

[0038] Figure 7The XRD patterns of PVDF powder and PVDF mono-oriented fibers in Example 2 are shown below.

[0039] Figure 8 The image shows the microstructure of the PVDF / Ag composite mono-oriented fiber in Example 3.

[0040] Figure 9 The image shows the microstructure and elemental distribution of the PVDF / BaTiO3 composite mono-oriented fiber in Example 4.

[0041] Figure 10 The image shows the microstructure of the PVDF / BaTiO3 composite bidirectional fiber in Example 5.

[0042] Figure 11 The image shows the microstructure of the PVDF / BaTiO3 composite mono-directional fiber before and after hot pressing in Example 5. Detailed Implementation

[0043] The following will describe the concept and technical effects of the present invention clearly and completely with reference to embodiments, so as to fully understand the purpose, features and effects of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are all within the scope of protection of the present invention.

[0044] In the description of the embodiments of the present invention, if a feature is referred to as "setting," "fixing," "connecting," or "installing" on another feature, it can be directly set, fixed, or connected to the other feature, or it can be indirectly set, fixed, connected, or installed on the other feature. The use of "first" and "second" in the description is for the purpose of distinguishing technical features only, and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0045] Example 1

[0046] See Figure 1 , Figure 1This is a schematic diagram of the fiber preparation system according to the first embodiment of the present invention, including a feeding device 100, a flow guiding kit 200, and a fiber collecting device 400. The feeding device 100 includes a moving part 110 and a container 120. The container 120 has a receiving cavity for containing fiber solution. The container 120 is provided with a liquid outlet 121. The receiving volume of the container 120 can be reduced by driving the moving part 110 to move or by moving the container 120, so that the fiber solution contained in the container 120 flows out from the liquid outlet 121. The flow guide kit 200 is sealed to the feeding device 100. The flow guide kit 200 is provided with an air inlet 210 and an air outlet 220. The function of the sealed connection is to ensure that the gas introduced by the air supply device 300 comes out along the air outlet 220, so as to control the direction and flow rate of the gas. The liquid outlet 121 extends into the interior of the air outlet 220 or extends out of the air outlet 220 to the outside of the flow guide kit 200. This allows the gas introduced from the air inlet 210 to come out of the air outlet 220, and the gas wraps around and pulls the outflowing fiber liquid to form a single fiber 122. The formed single fiber 122 is collected by the fiber collecting device 400.

[0047] In some embodiments, the fiber collecting device 400 includes a drive motor 410 and a roller 420. The roller 420 is axially mechanically connected to the drive motor 410 and is used to pull single fibers for continuous production and to wind single fibers for directional collection. During collection, the liquid outlet 121 is aligned with or slightly above the upper surface of the roller 420. The fiber liquid flowing out of the liquid outlet 121 moves forward to the upper surface of the roller 420 under the traction of the airflow, and then winds around the roller 420 as the roller 420 rotates. In some embodiments, the speed of the drive motor is 0 to 1000 rad / min, the diameter of the roller is 10 mm, and the width is 31.4 mm. In some embodiments, the roller 420 is provided with a film, which includes, but is not limited to, writing paper, aluminum foil, polymer film, or other flexible films. Single fibers 122 are formed on the film and can be removed together with the fibers after collection. They can then be used as part of the fiber as consumables.

[0048] In some embodiments, the fiber preparation system includes a gas supply device 300, which includes, but is not limited to, a vortex fan, a centrifugal fan, an air compressor, or a high-pressure gas cylinder, and the gas supplied is one or more of air, nitrogen, argon, or oxygen.

[0049] In some embodiments, the liquid outlet 121 extends into the center of the air outlet 220, which enables the gas coming out of the air outlet 220 to uniformly wrap the fiber liquid flowing out of the liquid outlet 121, that is, the gas pressure around the fiber liquid is balanced, thereby making the force of the gas pulling the fiber liquid uniform, and thus making the formed single fiber 122 pulled out in a straight line.

[0050] In some embodiments, the liquid outlet 121 has the same liquid outlet direction as the gas outlet 220. The liquid outlet direction and the gas outlet direction are consistent and without angle, so that the fibers that can be formed are straight and without bends.

[0051] In some embodiments, the air inlet 210 and the air outlet 220 have the same cross-sectional area, such as the air inlet 210 and the air outlet 220 being circles with the same radius.

[0052] In some embodiments, the air inlet 210 is perpendicular to the air outlet 220, which facilitates ventilation.

[0053] In some embodiments, the feeding device 100 is a syringe, the moving part 110 is a structure formed by the piston and piston shaft of the syringe, the liquid outlet 121 is the needle of the syringe, the open end 230 of the flow guide kit 200 is sealed to the end of the feeding device 100 having the liquid outlet 121, so that the flow guide kit 200 is sealed to the feeding device 100, and the needle extends into the air outlet 220 of the flow guide kit 200 and extends out from the air outlet 220. In other embodiments, the flow guide 200 is cylindrical and coaxial with the syringe. The diameter of the air inlet 210 is 1mm to 5mm, and the diameter of the air outlet 220 is 1mm to 5mm. The center of the air inlet 210 is located 5mm from the open end 230. The distance between the end of the liquid outlet 121 and the end face of the air outlet 220 is 0mm to 10mm (when the distance between the end of the liquid outlet 121 and the end face of the air outlet 220 is greater than 0, it indicates that the end face of the liquid outlet 121 extends from the outer surface 222 of the air outlet 220 to the outside of the flow guide 200, such as...). Figure 1 The location shown. See also Figure 2 The liquid outlet 121 is located within the air outlet 220. Specifically, when the liquid outlet 121 extends between the inner surface 221 and the outer surface 222 of the air outlet 220, the distance between the end faces is 0 mm, meaning the liquid outlet 121 extends into the interior of the air outlet 220. The diameters of the air inlet 210 and the air outlet 220 are consistent, and the flow guide assembly 200 is sealed to the syringe.

[0054] In some embodiments, the feeding device 100 further includes a second driving device 130 for quantitatively and stably driving the movement of the moving component 110. In some embodiments, the second driving device 130 is an injection pump. In some embodiments, the feeding device 100 includes an injection pump and a syringe. The injection pump can control the flow rate of the syringe within the range of 0.1 μL / min to 100 μL / min, the inner diameter of the syringe cavity is controlled within the range of 3 mm to 8 mm, and the syringe tube material can be one of metal, polymer, or glass. In some embodiments, the inner diameter of the syringe needle tip is within the range of 90 μm to 1000 μm, the needle shape is conical or cylindrical, and the material is one of polymer, glass, or metal.

[0055] See Figure 3 , Figure 3 This is a schematic diagram of the fiber preparation system according to the second embodiment of the present invention. The fiber preparation system also includes a first driving device 500. The feeding device 100 is fixed on the first driving device 500 and can move unidirectionally or reciprocally with the first driving device 500. The direction of the unidirectional or reciprocating movement is perpendicular to the liquid outlet direction of the liquid outlet 121. For example, in some embodiments, the feeding device 100 discharges liquid in the horizontal direction, and then the single fiber 122 is horizontally drawn under the traction of the gas introduced by the gas supply device 300, and then collected on the fiber collecting device 400. The first driving device 500 moves in the horizontal plane perpendicular to the liquid outlet direction, so that the single fiber 122 formed after being pulled and stretched after the liquid is discharged can be oriented and spaced.

[0056] In some embodiments, the first drive device 500 is a reciprocating machine, and the feeding device 100 is mechanically rigidly connected, such as by welding or screw fixing, or detachably connected to the reciprocating machine, and moves unidirectionally or reciprocally with the reciprocating machine. In some embodiments, the movement speed of the reciprocating machine is 1 mm / min to 100 mm / min, and the maximum stroke is 40 cm.

[0057] Taking the fiber preparation system of the second embodiment as an example, its working process is as follows:

[0058] The prepared fiber solution is loaded into the container 120 of the feeding device 100, and the moving part 110 is moved by the driving device 130 so that the fiber solution contained in the container 120 flows out from the outlet 121.

[0059] The gas supply device 300 is turned on to provide gas. The gas enters from the air inlet 210 of the flow guide kit 200 and exits from the air outlet 220. The fiber liquid flowing out of the liquid outlet 121 is stretched into a ray-shaped liquid flow under the traction of the air flow. It moves forward to form a single fiber 122 and is collected by the fiber collection device 400.

[0060] The first driving device 500 drives the feeding device 100 to perform unidirectional or reciprocating motion. The direction of the unidirectional or reciprocating motion is perpendicular to the liquid discharge direction of the liquid outlet 121, so that the single fibers 122 are oriented and spaced on the fiber collecting device 400.

[0061] Example 2: PVDF unidirectional fiber

[0062] See Figure 4 This embodiment provides a PVDF unidirectional fiber, prepared using the fiber preparation system of Example 1, specifically including the following preparation steps:

[0063] (1) Preparation of fiber solution: Take 8g DMF and 2g acetone and put them into a glass bottle. Mix them evenly by shaking. Then weigh 2g of PVDF powder with a molecular weight of 60W and add it to the glass bottle. Seal the glass bottle and stir at 70℃ for 6 hours to obtain a transparent and clear PVDF fiber solution.

[0064] (2) In this embodiment, the feeding device includes a syringe and an injection pump. The first driving device used is a reciprocating machine, and the fiber collection device used includes a drive motor and a roller. After the fiber solution is cooled to room temperature, it is loaded into the syringe. The gas in the syringe is emptied, and a metal needle with an inner diameter of 120 micrometers is installed. The syringe is fixed to the injection pump, and the flow rate of the syringe is set to 19 μL / min. The reciprocating machine is set to run in one direction at a speed of 1 mm / min. The flow guide kit is tightly fixed to the front end of the syringe so that the length of the needle extending out of the air port is 1 mm. The flow rate of the starting airflow introduced by the air supply device is set to 8 SLPM. A layer of PP film is covered on the surface of the roller. The drive motor is turned on, and the roller speed is set to 250 rad / min.

[0065] (3) After completing the above preparations, turn on the drive motor, air supply device, injection pump and reciprocating machine in sequence.

[0066] See Figure 5 After the air supply device is turned on, the fiber liquid flowing from the tip of the syringe needle is stretched into a ray-shaped liquid stream under the traction of the airflow. It moves forward to the surface of the roller and adheres to it. Then, under the torque and high-speed rotation of the roller, it wraps around its surface. After a single fiber is started, the airflow of the air supply device is adjusted to 4 SLPM to form an auxiliary airflow. Under the action of the roller torque stretching and the auxiliary airflow, the solvent in the single liquid stream pulled out from the needle tip evaporates rapidly, and the liquid stream solidifies into fiber.

[0067] As the roller rotates, the fiber solution continuously supplied at the needle is drawn out and solidified into fibers, which are then wound around the surface of the roller. When the reciprocating machine carries the needle and moves unidirectionally along the roller axis, a fixed spacing is generated between two adjacent turns of the wound fibers, and each turn of the fibers is parallel to each other.

[0068] After collection is complete, stop the injection pump, reciprocating machine, air supply device, and drive motor in sequence. Cut the PP film on the surface of the roller along the axial direction and unfold it to obtain PVDF unidirectional fibers with a length equal to the circumference of the roller.

[0069] Figure 6 The image shows the microstructure of the PVDF mono-oriented fiber prepared in this embodiment. As can be seen from the image, the PVDF mono-oriented fiber has a high degree of orientation, a fiber diameter of 4 μm, and a center-to-center distance of 4 μm between adjacent fibers. Figure 7 The images show the XRD patterns of PVDF powder and the PVDF unidirectional fiber prepared in this embodiment. The PVDF powder is in the γ phase, while the PVDF unidirectional fiber prepared by the method of this embodiment is in the β phase. This indicates that the PVDF unidirectional fiber was subjected to strong stretching during the preparation process, which caused the PVDF to undergo a phase transformation and obtain a high degree of crystallinity. As a result, the PVDF unidirectional fiber prepared in this embodiment has better mechanical and electrical properties.

[0070] Example 3: PVDF / Ag composite unidirectional fiber

[0071] This embodiment provides a PVDF / Ag composite unidirectional fiber, prepared using the fiber preparation system of Example 1, specifically including the following preparation steps:

[0072] (1) Preparation of fiber solution: Take 9g DMF, 1g acetone and 0.2g Ag nanoparticles and put them into a glass bottle. Disperse and mix them evenly by ultrasonication. Then weigh 1.8g of PVDF powder with a molecular weight of 50W and add it to the glass bottle. Seal the glass bottle and stir at 70℃ for 6h to obtain green viscous PVDF / Ag fiber solution.

[0073] (2) In this embodiment, the feeding device includes a syringe and an injection pump. The first driving device used is a reciprocating machine, and the fiber collection device used includes a drive motor and a roller. After the fiber solution is cooled to room temperature, it is loaded into the syringe, the gas in the syringe is emptied, and a metal needle with an inner diameter of 160 micrometers is installed. The syringe is fixed to the injection pump, and the injection speed is set to 12 μL / min. The reciprocating machine is set to run in one direction at a speed of 1 mm / min. The flow guide kit is tightly fixed to the front end of the syringe so that the length of the needle extending out of the air port is 1 mm. The flow rate of the starting airflow into the air supply device is set to 9 SLPM. A layer of PP film is covered on the surface of the roller, the starting motor is turned on, and the roller speed is set to 400 rad / min.

[0074] (3) After completing the above preparations, turn on the drive motor, air supply device, injection pump, and reciprocating machine in sequence. The fiber solution injected from the needle tip of the syringe is stretched into a ray-shaped liquid stream under the traction of the airflow, moves forward to the surface of the roller and adheres to it. Then, under the action of the roller's torque and high-speed rotation, it wraps around its surface. After a single fiber is started, the airflow of the air supply device is adjusted to 4 SLPM to form an auxiliary airflow. Under the action of the roller's torque stretching and the auxiliary airflow, the solvent of the single liquid stream pulled out from the needle tip evaporates rapidly, and the liquid stream solidifies into fiber.

[0075] As the roller rotates, the raw liquid continuously supplied at the needle is drawn out and solidified into fibers, which are then wrapped around the surface of the roller. When the reciprocating machine carries the needle and moves unidirectionally along the roller axis, a fixed spacing is generated between two adjacent loops of fibers, and each loop of fibers is parallel to each other.

[0076] After collection is complete, stop the injection pump, reciprocating machine, air supply device, and drive motor in sequence. Cut the PP film on the surface of the roller along the axial direction and unfold it to obtain PVDF / Ag composite monodirectional fibers with a length equal to the circumference of the roller.

[0077] Figure 8 The image shows the microstructure of the PVDF / Ag composite mono-oriented fiber prepared in this embodiment. As can be seen from the image, the PVDF / Ag composite mono-oriented fiber has a high degree of orientation, a fiber diameter of 2.5 μm, and a center-to-center distance of 2.5 μm between adjacent fibers.

[0078] Example 4: PVDF / BaTiO3 composite unidirectional fiber

[0079] This embodiment provides a PVDF / BaTiO3 composite unidirectional fiber, which is prepared using the fiber preparation system of Example 1, and specifically includes the following preparation steps:

[0080] (1) Preparation of fiber solution: Take 9g DMF, 1g acetone and 0.4g BaTiO3 nanoparticles and put them into a glass bottle. Mix them evenly by ultrasonic dispersion and high-speed stirring. Then weigh 1.6g of PVDF powder with a molecular weight of 40W and add it to the glass bottle while stirring. Seal the glass bottle and stir at 70℃ for 6h to obtain a white viscous PVDF / BaTiO3 fiber solution.

[0081] (2) In this embodiment, the feeding device includes a syringe and an injection pump. The first driving device used is a reciprocating machine, and the fiber collection device used includes a drive motor and a roller. After the spinning solution is cooled to room temperature, it is loaded into the syringe, the gas in the syringe is purged, and a metal needle with an inner diameter of 160 micrometers is installed. The syringe is fixed to the injection pump, and the injection speed is set to 2.5 μL / min. The reciprocating machine is set to run in one direction at a speed of 5 mm / min. The flow guide kit is tightly fixed to the front end of the syringe so that the length of the needle extending out of the air port is 2 mm. The flow rate of the starting airflow into the air supply device is set to 10 SLPM. A layer of aluminum foil is covered on the surface of the roller, the starting motor is turned on, and the roller speed is set to 500 rad / min.

[0082] (3) After completing the above preparations, turn on the drive motor, air supply device, injection pump, and reciprocating machine in sequence. The original liquid injected from the needle tip is stretched into a ray-shaped liquid stream under the traction of the airflow, moves forward to the surface of the roller and adheres to it. Then, under the action of the roller's torque and high-speed rotation, it wraps around its surface. After the single fiber is started, the airflow of the air supply device is adjusted to 6 SLPM to form an auxiliary airflow. Under the action of the roller's torque stretching and the auxiliary airflow, the solvent of the single liquid stream pulled out from the needle tip evaporates rapidly, and the liquid stream solidifies into fiber.

[0083] As the roller rotates, the raw liquid continuously supplied at the needle is drawn out and solidified into fibers, which are then wrapped around the surface of the roller. When the reciprocating machine carries the needle and moves unidirectionally along the roller axis, a fixed spacing is generated between two adjacent loops of fibers, and each loop of fibers is parallel to each other.

[0084] After collection is complete, stop the injection pump, reciprocating machine, air supply device, and drive motor in sequence. Cut the PP film on the surface of the roller along the axial direction and unfold it to obtain PVDF / BaTiO3 composite unidirectional fibers with a length equal to the circumference of the roller.

[0085] Figure 9 The image shows the microstructure and elemental distribution of the PVDF / BaTiO3 composite mono-oriented fibers prepared in this embodiment. As can be seen from the image, the PVDF / BaTiO3 composite mono-oriented fibers have a high degree of orientation, a fiber diameter of 1 μm, and a center-to-center distance of 5 μm between adjacent fibers. EDS elemental analysis shows that the distribution of Ti, Ba, and F elements is completely consistent with the distribution of the fibers, indicating that the BaTiO3 particles are very uniformly dispersed in the PVDF matrix.

[0086] Example 5: PVDF / BaTiO3 composite bidirectional fiber

[0087] This embodiment provides a PVDF / BaTiO3 composite bidirectional fiber, which is prepared according to the following steps:

[0088] (1) Preparation of PVDF / BaTiO3 composite unidirectional fiber: The preparation process is the same as in Example 4, except that the roller surface is covered with aluminum foil and the spacing between adjacent fibers is different.

[0089] (2) Take two aluminum foils loaded with PVDF / BaTiO3 composite unidirectional fibers, stack the fiber-loaded sides together, and make the cross angle of the two fiber layers 90°; place the stacked aluminum foils horizontally on a ceramic heating table, and apply pressure horizontally above them using a ceramic plate. The heating temperature is set to 160℃, the pressure is 0.3 MPa, and the hot pressing time is 30 min. Here, the pressure should be applied after the temperature rises to 160℃. After the hot pressing is completed, slowly cool down to room temperature to obtain PVDF / BaTiO3 composite bidirectional fibers.

[0090] Figure 10 This is a microscopic morphology image of the PVDF / BaTiO3 composite bidirectional fibers prepared in this embodiment. As can be seen from the image, the PVDF / BaTiO3 composite bidirectional fibers have a high degree of orientation in two directions, with a transverse spacing of 50 μm, a vertical spacing of 55 μm, an angle of 90° between the two directions, and a fiber diameter of 3 μm. Figure 11 As shown, before hot pressing, the fibers at the intersections are not connected but only in contact. After hot pressing, the fibers at the intersections are fused together, and the bidirectional fibers become one, forming a regular network structure.

[0091] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention. Furthermore, the embodiments of the present invention and the features thereof can be combined with each other unless otherwise specified.

Claims

1. A method of making a fiber with a fiber making system, characterized by, The fiber preparation system includes: A feeding device includes a moving part and a container. The container has a receiving cavity for containing fiber solution. The container is provided with a liquid outlet. The moving part is movable relative to the container so that the fiber solution flows out from the liquid outlet. A flow guide kit is sealed to the feeding device. The flow guide kit is provided with an air inlet and an air outlet. The liquid outlet extends into the interior of the air outlet or extends from the air outlet to the exterior of the flow guide kit to form a single fiber. A fiber collecting device for collecting the single fiber; The fiber collecting device includes a drive motor and a drum, wherein the drive motor is used to drive the drum to rotate; The fiber preparation system further includes a first driving device, which drives the feeding device to perform unidirectional or reciprocating motion, the direction of which is perpendicular to the liquid outlet direction; the first driving device is a reciprocating machine. The method includes the following steps: A fiber solution is added to the container of the feeding device, and the moving part is moved to make the fiber solution flow out from the outlet; the fiber solution includes PVDF and a solvent. Start the air supply device and introduce a starting airflow into the air inlet to draw the fiber solution into a single fiber; The fiber collecting device is started, and the rotational speed of the roller in the fiber collecting device is controlled to be 250 rad / min to 500 rad / min. After the fiber collecting device collects the single fiber, an auxiliary airflow is introduced into the air inlet or the airflow is turned off. The subsequent continuous growth is completed by the traction of the rotational torque of the roller. During this preparation process, the single fiber is stretched by the rotational torque of the roller, causing the PVDF in it to undergo a phase transformation from the γ phase to the β phase. The flow rate of the auxiliary airflow is less than the flow rate of the starting airflow. The feeding device is driven by the first driving device to perform the unidirectional motion or the reciprocating motion, so that the single fibers are oriented and evenly spaced on the fiber collecting device.

2. The method of claim 1, wherein, The roller is covered with a film.

3. The method of claim 2, wherein, The coating can be any one of writing paper, aluminum foil, or polymer film.

4. The method of claim 1, wherein, The feeding device further includes a second driving device, which is used to drive the moving component to move.

5. The method of claim 4, wherein, The second driving device is an injection pump.

6. The method according to any one of claims 1 to 5, characterized in that, The flow guiding kit is cylindrical, the feeding device is a syringe, and the flow guiding kit is coaxial with the feeding device.

7. The method according to any one of claims 1 to 5, characterized in that, The liquid outlet has the same liquid outlet direction as the gas outlet direction.

8. The method according to any one of claims 1 to 5, characterized in that, The air inlet and the air outlet have the same cross-sectional area.

9. The method according to any one of claims 1 to 5, characterized in that, The fiber preparation system also includes a gas supply device for introducing gas into the air inlet.

10. The method of claim 1, wherein, The flow rate of the starting airflow is 1 SLPM to 10 SLPM.

11. The method of claim 1, wherein, The first driving device operates at a speed of 1 mm / min to 100 mm / min, and the feeding device supplies the fiber solution at a speed of 0.1 μL / min to 100 μL / min.

12. The method of claim 1, wherein, The method also includes the steps of: stacking and hot-pressing the fibers collected on the fiber collecting device, wherein the angle between the extension directions of different layers of fibers during the stacking process is 1° to 90°.

13. The method according to any one of claims 1, 10 to 12, characterized in that, The fiber solution also includes at least one of barium titanate, zinc oxide, silicon oxide, iron oxide, silver, and zirconium oxide.

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