Ultrasonic-assisted liquid-jet bubble spinning device

Abstract

The invention provides an ultrasonic-assisted liquid-jet bubble spinning device, and belongs to the field of spinning mechanical equipment. The spinning device comprises a bubble assembly, a liquid storage assembly, a drafting assembly, a flow dividing assembly and a receiving assembly. According to the device, gas is introduced into the liquid storage tank through the bubble assembly to generate bubbles, and the introduced large bubbles are dispersed into uniform small bubbles through the ultrasonic vibration device. And the bubbles are controlled to be output stage by stage through the guide wheel to realize uniform conveying of the bubbles. In addition, high-pressure airflow generated by an air compressor is used for blowing and breaking bubbles and drafting the bubbles, so that the preparation of nanofibers is realized. According to the bubble spinning device, uniform generation and supply of solution bubbles can be achieved, the bubbles are conveyed in stages, nanofibers are safely and efficiently prepared, and the bubble spinning device has the advantages of being stable, safe and efficient.

Description

Technical Field

[0001] The invention relates to an ultrasonic auxiliary liquid jet bubble spinning device, belonging to the technical field of spinning machinery and equipment. Background Art

[0002] Micro-nano fibers refer to fiber materials with diameters ranging from micrometers to nanometers. They have shown great application potential in many fields due to their high specific surface area, high porosity and unique surface effects. In recent years, with the continuous development of materials science and nanotechnology, the preparation technology and application research of micro-nano fibers have made significant progress.

[0003] At present, common methods for preparing nanofibers include electrospinning, centrifugal method, sol-gel method, bubble spinning method, liquid jet spinning method, etc. Among them, electrospinning is one of the most commonly used methods for preparing micro-nano fibers. Its principle is to form a jet from a polymer solution or melt under the action of a high-voltage electric field, and the jet is continuously stretched and refined under the action of the electric field force and solvent volatilization, and finally solidifies to form micro-nano fibers. This method has the advantages of simple equipment, convenient operation, and the ability to prepare micro-nano fibers of various materials. However, the electrospinning method has low production efficiency, extremely harsh spinning conditions, and strict requirements on solution configuration. At the same time, due to the presence of a high-voltage electrostatic field, there are certain production risks. Centrifugal spinning equipment and process costs are high, production efficiency is low, and requirements on solution properties are strict. In addition, the diameter of the obtained nanofibers is difficult to control, and the fiber orientation and arrangement are difficult to control. The sol-gel method has a long cycle time for preparing nanofibers, sensitive process parameters, and the use of organic solvents increases the risk of environmental pollution and health effects. In this regard, innovation in nanofiber production methods is extremely important.

[0004] Bubble spinning is a new type of spinning technology that usually does not require complex mechanical transmission and high-precision nozzle design. It mainly relies on the pressure and flow generated by gas to achieve spinning. Bubble spinning can achieve continuous production. Since the generation and rupture of bubbles are relatively fast, a large number of fibers can be prepared in a short time, which makes large-scale industrial production possible. Liquid jet spinning is a spinning technology that shears and stretches polymer solutions through high-speed airflow to form nano-scale fibers. It extrudes the polymer solution through the spinneret, uses the impact force of compressed gas to refine the solution flow, accelerates the evaporation of the solvent, and finally obtains a nanofiber membrane. Liquid jet bubble spinning is a nanofiber technology that combines bubble generation and airflow stretching. Compared with traditional spinning methods such as electrospinning, which requires high-voltage equipment, and melt-blown spinning, which requires high-temperature melting equipment, its equipment structure is relatively simple and has a high safety factor. At the same time, there is no need to strictly control parameters such as voltage and electric field distribution in electrospinning; there is no need to accurately control the basic speed and temperature of the solution like in solution spinning, which reduces the technical requirements and operation difficulty of operators. Liquid-jet bubble spinning can be used to blend a variety of polymer materials or different types of polymers to obtain fiber materials with special properties. It can also change the spinning parameters to prepare fibers of different diameters and shapes. In addition, this method does not use extreme conditions or large amounts of organic solvents, produces less waste, and has less pressure on the environment, which is in line with the development trend of green environmental protection.

[0005] As people's requirements for fibers increase, the nanofiber spinning technology has begun to be optimized and designed. The preparation of spinning solution, the generation and control of bubbles, the control of the spinning process, and the collection and post-processing of fibers are the key processes of spinning. Among them, the generation and control of bubbles play a vital role in the formation of fibers. The formation and rupture of bubbles can generate the power to stretch the spinning solution into fibers. If bubbles cannot be generated or the generation efficiency is unstable, it is difficult to provide continuous and stable power to form fibers from the spinning solution. At the same time, the uniformity and stability of bubble generation are directly related to the stability of the spinning solution jet. The bubbles generated uniformly and stably can make the spinning solution ejected from the jet port at a uniform speed and flow rate, forming a stable jet, which is conducive to continuous and uniform fiber preparation. On the contrary, the uneven or irregular generation of bubbles will lead to unstable jets, causing problems such as uneven thickness and breakage of fibers. CN209468530U discloses a porous bubble electrostatic spinning device, wherein the upper end of the bubble generator is provided with a plurality of evenly distributed small holes, so that evenly distributed bubbles are generated on the liquid surface, so that the bubbles are broken in a certain pattern, thereby making the nanofiber membrane more uniform. In the invention disclosure patent of CN105937056B, a bubble electrostatic spinning device and method with controllable gas volume is disclosed, which is connected to the solenoid valve and the precision injection pump respectively through a programmable controller, and is used to control the on and off of the solenoid valve and the working stroke of the screw nut in the precision injection pump for a single operation, so as to control the gas volume to control the shape of the bubble and improve the quality of nano spinning. In the invention disclosure patent of CN105671656B, a device is disclosed that uses a bubble device to form bubbles, and after the bubbles burst, a high-speed airflow is used as a power to stretch and refine the production of micro-nano fibers. CN112981557B discloses a waterwheel-type bubble spinning device, which uses a waterwheel-type bracket to rotate and drive the spinning solution in the liquid storage tank, and uses the jet airflow to achieve uninterrupted continuous spinning. CN105350090B discloses a negative pressure bubble electrostatic spinning device, which realizes the directional deposition of nanofibers on the collector into fibers with a specific shape structure through a high-voltage power supply device and a negative pressure receiving device.

[0006] Currently, common nanofiber preparation processes include electrospinning, centrifugal spinning, sol-gel method, etc., but these processes require relatively complex solution conditions, production processes and production conditions, and have certain safety hazards, endangering the lives and health of production personnel.

[0007] The most commonly used bubble spinning process currently uses electric field force as traction force and utilizes the principle of bubble dynamics to make the polymer solution or melt form a Taylor cone under the action of electric field force and produce countless tiny bubbles. These bubbles are stretched and refined under the action of electric field force, and finally form nano-scale fibers. This method has the problems of large jet angle and unstable jet, which makes it difficult to control the spinning conditions, wastes raw materials, and pollutes the environment.

[0008] At present, the commonly used methods of bubble spinning to produce bubbles include pressurized dissolution, vortex, heating evaporation and mechanical stirring. The pressurized and heated methods of producing bubbles have a certain risk factor; the vortex and stirring methods cannot control the amount and stability of bubbles produced, and these uncertain factors will affect production. Summary of the invention

[0009] The purpose of the present invention is to provide an ultrasonic-assisted liquid-jet bubble spinning device, which generates bubbles in the spinning solution by gas introduction and ultrasonic assistance, thereby stretching the spinning solution by high-pressure gas to produce nanofibers. Large bubbles are introduced into the spinning solution by a gas generating device, and then the large bubbles are dispersed into uniform small bubbles by ultrasonic vibration, so as to output them for spinning, thereby achieving continuous and uniform generation of bubbles and continuous and uniform preparation of nanofibers.

[0010] To solve the above technical problems, the purpose of the present invention is achieved as follows:

[0011] The ultrasonic-assisted liquid-jet bubble spinning device of the present invention comprises a bubble component, a liquid storage component, a drafting component, a flow diversion component and a receiving component;

[0012] The bubble assembly comprises a bubble generating device and a bubble conveying device, wherein the bubble generating device is used to generate bubbles, and the bubble conveying device is used to convey the bubbles into the polymer solution;

[0013] The liquid storage component includes a liquid storage tank, a liquid storage cover and an ultrasonic vibration device. The liquid storage tank is used to place the polymer solution, and the liquid storage cover is used to seal the top of the liquid storage tank to ensure the formation of a negative pressure space. There are multiple ultrasonic vibration devices, which are placed around the liquid storage tank and are used to provide ultrasonic vibration to disperse the large bubbles transported by the bubble component into small bubbles.

[0014] The stretching assembly includes an air compressor, a pressure regulating valve and a gas delivery pipeline, wherein the air compressor is used to generate high-pressure air; the pressure regulating valve is used to adjust the gas pressure of the air compressor; and the gas delivery pipeline is used to transport high-pressure air to stretch the polymer solution and bubbles;

[0015] The diversion component includes a speed controller, a motor and a guide wheel. The speed controller is used to control the speed of the motor; the motor is used to drive the guide wheel to rotate, and the guide wheel is used to rotate and extrude the bubble transport hose.

[0016] On the basis of the above scheme and as a preferred scheme of the above scheme: the receiving component includes a transmission wheel, a receiving mesh curtain, a fixing device and a base, the transmission wheel is used to drive the receiving mesh curtain to rotate, the receiving mesh curtain is used to receive nanofibers, the fixing device is used to fix the transmission wheel and the receiving mesh curtain, and the base is used to support the entire receiving component.

[0017] On the basis of the above scheme and as a preferred scheme of the above scheme: the guide wheel is a three-way guide wheel with three external wheel sets; the external wheel sets are rotatable.

[0018] On the basis of the above solution and as a preferred solution of the above solution: a sealing strip is provided inside the liquid storage cover.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1. In the present invention, the introduction and dispersion of bubbles are achieved by air flow introduction and ultrasonic vibration assistance. The bubble generating device is used to deliver bubbles into the liquid storage tank. The bubbles are subjected to ultrasonic vibration and decomposed into a number of uniform small bubbles, thereby increasing the coverage of the polymer solution.

[0021] 2. In the present invention, a three-way guide wheel is designed to control the uniform output of bubbles. The three-way guide wheel is driven by the central motor and rotates at a uniform speed at a set speed. The guide wheel regularly and slowly squeezes the hose to control the delivery and stop of bubbles in the hose, forming a segmented output of bubbles.

[0022] 3. In the present invention, the three-way guide wheel is used to uniformly squeeze the hose to transport the bubbles, forming a negative pressure area in the liquid storage area, and the bubbles are automatically transported to the outlet under the action of pressure.

[0023] 4. In the present invention, high-pressure airflow is used to blow bubbles and stretch the polymer solution. The electrostatic field effect is eliminated and replaced by high-pressure and high-speed airflow, which reduces production risks and simplifies process difficulty. At the same time, the air compressor valve can be adjusted to control the thickness of the obtained fiber by adjusting the air pressure.

[0024] 5. In the present invention, the liquid-jet spinning process and the bubble spinning process are combined, and the bubbles are blown up by high-pressure airflow to volatilize the solvent and draw the nanofibers. This nanofiber production process greatly increases the output of nanofibers. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic structural diagram of the ultrasonic-assisted liquid-jet bubble spinning device involved in the present invention;

[0026] Figure 2 It is a technical roadmap of the ultrasonic-assisted liquid-jet bubble spinning device involved in the present invention;

[0027] Figure 3 is a SEM image of nanofibers prepared by the ultrasonic-assisted liquid-jet bubble spinning device of the present invention;

[0028] Figure 4 It is a diameter distribution diagram of nanofibers prepared by the ultrasonic-assisted liquid-jet bubble spinning device of the present invention;

[0029] Figure 5 It is a schematic diagram of the structure of a liquid jet spinning device used in the prior art;

[0030] Figure 6 It is a SEM picture of nanofibers prepared by using a liquid jet spinning device using the existing technology;

[0031] Figure 7 It is a diameter distribution diagram of nanofibers prepared by using a liquid jet spinning device using existing technology. DETAILED DESCRIPTION

[0032] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0033] Example

[0034] Combination Figures 1 to 4 The present embodiment is described in detail. The ultrasonic-assisted liquid-jet bubble spinning device of the present embodiment comprises a bubble assembly 10 , a liquid storage assembly 20 , a drafting assembly 30 , a flow diversion assembly 40 and a receiving assembly 50 .

[0035] The bubble assembly 10 includes a bubble generating device 11 and a bubble conveying device 12 . The bubble generating device 11 is used to generate bubbles, and the bubble conveying device 12 is used to convey the bubbles into the polymer solution.

[0036] The liquid storage component 20 includes a liquid storage tank 21, a liquid storage cover 22 and an ultrasonic vibration device 23. The liquid storage tank 21 is used to place the polymer solution, and the liquid storage cover 22 is used to seal the top of the liquid storage tank 21 to ensure the formation of a negative pressure space; there are multiple ultrasonic vibration devices 23, which are placed around the liquid storage tank 21 to provide ultrasonic vibration to disperse the large bubbles transported by the bubble component 10 into small bubbles.

[0037] The stretching assembly 30 includes an air compressor 31, a pressure regulating valve 32 and a gas delivery pipeline 33. The air compressor 31 is used to generate high-pressure air; the pressure regulating valve 32 is used to adjust the gas pressure of the air compressor 31; and the gas delivery pipeline 33 is used to transport high-pressure air to stretch the polymer solution and bubbles.

[0038] The diversion component 40 includes a speed controller 41, a motor 42 and a guide wheel 43. The speed controller 41 is used to control the speed of the motor 42; the motor 42 is used to drive the guide wheel 43 to rotate, and the guide wheel 43 is used to rotate and squeeze the bubble transport hose.

[0039] Furthermore, the guide wheel 43 is a three-way guide wheel having three external wheel sets; the external wheel sets are rotatable.

[0040] The receiving component 50 includes a transmission wheel 51, a receiving mesh curtain 52, a fixing device 53 and a base 54. The transmission wheel 51 is used to drive the receiving mesh curtain 52 to rotate, and the receiving mesh curtain 52 is used to receive nanofibers. The fixing device 53 is used to fix the transmission wheel 51 and the receiving mesh curtain 52. The base 54 is used to support and fix the entire receiving component 50 to prevent it from tipping over.

[0041] Furthermore, the liquid storage cover 22 has a sealing strip inside for sealing the liquid storage tank 21 .

[0042] In order to better illustrate the process provided by the present invention, the implementation process of the ultrasonic-assisted liquid-jet bubble spinning device is shown, as described in the following steps:

[0043] 1. Preparation of spinning solution

[0044] According to different production requirements, polymer solutions with different functions are configured.

[0045] 2. Preparation of Nanofibers

[0046] The nanofiber preparation process used in the present invention is air bubble spinning, which is a method of forming fibers from bubbles or liquid films generated by polymer solutions or melts by means of flow. The airflow can stretch and pull the bubbles or liquid films, so that the polymers therein are solidified and formed into fibers during the flow process, thus avoiding problems such as electrostatic pollution caused by high voltage static electricity.

[0047] First, turn on the air compressor 31 in the drafting component 30, and set the required air flow pressure by adjusting the pressure regulating valve 32. Secondly, turn on the built-in motor in the receiving component 50 to set a suitable rotation speed, drive the transmission wheel 51 to rotate, and thus drive the receiving mesh curtain 52 to rotate. Turn on the motor 42 in the diversion component 40, adjust the speed controller 41 to the required speed, and start the guide wheel 43 to rotate. Inject the configured polymer solution into the liquid storage tank 21 in the liquid storage component 20, turn on the bubble generating device 11 in the bubble component 10, and transport bubbles into the liquid storage tank 21. Turn on the ultrasonic vibration device 23 around the liquid storage tank to disperse the large bubbles introduced by the bubble component 10 into uniform small bubbles.

[0048] The polymer solution envelops tiny bubbles in the liquid storage tank 21, and is gradually moved to the hose in an orderly manner due to the negative pressure brought by the diversion component 40. The output speed of the bubbles is controlled by the regular squeezing of the hose by the guide wheel 43. When the bubbles reach the hose outlet, the high-pressure and high-speed airflow generated by the air compressor 31 will blow the bubbles apart and stretch the polymer solution, so that the polymer solidifies into nanofibers and falls on the receiving mesh curtain 52.

[0049] The spinning experiment was carried out using the ultrasonic-assisted liquid-jet bubble spinning device of the present invention, and the specific process is as follows:

[0050] The polymer solution for making nanofibers is composed of polyacrylonitrile PAN, C3H3N and N,N-dimethylformamide DMF, C3H7NO. The precursor solution can be obtained by 8%-16% PAN and corresponding DMF by mass fraction. This product uses a spinning solution with a PAN content of 14% and a DMF content of 86%. It is formed after stirring at 60-75°C for 3-5 hours. This product is obtained by heating and stirring at 70°C for 3 hours.

[0051] When producing nanofibers, add the polymer solution to the liquid storage tank, turn on the air compressor, set the air pressure to 0.025Mpa-0.040Mpa, and this product uses 0.030Mpa. Turn on the receiving device, the receiving distance is 50cm, and the receiving net curtain starts to rotate at a uniform speed of 10cm / min. Turn on the control switch of the guide wheel 43 and adjust the speed to 30rpm. Turn on the bubble generating device with a delivery volume of 0.5L / min, so that the bubbles enter the polymer solution, turn on the ultrasonic vibration device around the liquid storage tank, and disperse the large bubbles into small bubbles.

[0052] The polymer solution enters the transport hose in the form of tiny bubbles under the action of the bubble generating device and the ultrasonic vibration device. As the guide wheel rotates, a negative pressure area is formed in the liquid storage area, causing the polymer bubbles to slowly move toward the outlet. Through the orderly rotation of the guide wheel, the bubbles are transported to the nozzle in a pointed manner. The high-pressure airflow generated by the air compressor is used to blow and stretch the polymer bubbles to form nanofibers. The receiving device obtains a nanofiber web with uniform thickness by continuously rotating at a uniform speed.

[0053] Comparative Example

[0054] The liquid jet spinning device used in this comparative example is Figure 5 As shown, it is mainly composed of a push injection assembly 60, a stretching assembly 70, a nozzle assembly 80 and a receiving assembly 90.

[0055] The push injection assembly 60 includes a syringe 61, a micro-injection pump 62 and an infusion catheter 63. The syringe 61 is used to store the polymer solution, the micro-injection pump 62 is used to push the syringe to squeeze out the polymer solution, and the infusion catheter 63 is used to transport the polymer solution.

[0056] The drafting assembly 70 includes an air compressor 71, a pressure regulating valve 72 and a gas delivery pipeline 73. The air compressor 71 is used to generate high-pressure gas, the pressure regulating valve 72 is used to adjust the air pressure, and the gas delivery pipeline 73 is used to deliver high-pressure gas.

[0057] The spray head assembly 80 includes a nozzle 81 and a needle 82. The nozzle 81 is used to adjust the direction of high-pressure gas, and the needle 82 is used to spray polymer.

[0058] The receiving component 90 includes a transmission wheel 91, a receiving mesh curtain 92, a fixing device 93 and a base 94. The transmission wheel 91 is used to drive the receiving mesh curtain 92 to rotate, the receiving mesh curtain 92 is used to receive nanofibers, the fixing device 93 is used to fix the transmission wheel 91 and the receiving mesh curtain 92, and the base 94 is used to support the entire receiving component 90.

[0059] The nanofibers are prepared by using a liquid jet spinning device, and the specific process is as follows:

[0060] The polymer solution used in the liquid-jet spinning device for producing nanofibers is composed of polyacrylonitrile PAN, C3H3N and N,N-dimethylformamide DMF, C3H7NO. The precursor solution can be obtained from PAN with a mass fraction of 8%-16% and the corresponding DMF. This product uses a spinning solution with a PAN content of 14% and a DMF content of 86%. It is formed after stirring at 60-75°C for 3-5 hours. This product is obtained by heating and stirring at 70°C for 3 hours. The liquid-jet nanofiber production process consists of a push injection component, a drafting component, a nozzle component and a receiving component. The extrusion rate of the polymer solution during the production of this product is 0.09mL / min, the air pressure is 0.025Mpa, the inner diameter of the needle is 0.39mm, and the receiving distance is 50cm.

[0061] The microstructure and fiber diameter of the nanofibers prepared in the embodiment and the comparative example are compared. Figure 4 and Figure 5 The SEM image of the nanofibers prepared in the example and the three-dimensional image of the distribution of fiber diameters are shown in Figure 1. It can be found from the figure that the diameters of the nanofibers produced by ultrasonic-assisted liquid-jet spinning are mainly distributed between 0.3 and 1.0 microns, and are mainly concentrated between 0.5 and 0.6 microns, that is, between 500 and 600 nanometers.

[0062] Figure 6 and Figure 7 The SEM image of the nanofibers prepared in the comparative example and the three-dimensional image of the distribution of fiber diameters are shown in Figure 1. It can be found from the figure that the diameters of the nanofibers produced by liquid jet spinning are mainly distributed between 0.2-1.3 microns, and are mainly concentrated between 0.6-0.8 microns, that is, between 600-800 nanometers.

[0063] However, the diameter of the nanofibers prepared by the ultrasonic-assisted liquid-jet bubble spinning device of the present invention is thinner.

[0064] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. An ultrasonic-assisted liquid-jet bubble spinning device, characterized in that: It comprises a bubble assembly (10), a liquid storage assembly (20), a drafting assembly (30), a flow diversion assembly (40) and a receiving assembly (50); The bubble assembly (10) comprises a bubble generating device (11) and a bubble conveying device (12), wherein the bubble generating device (11) is used to generate bubbles, and the bubble conveying device (12) is used to convey the bubbles into the polymer solution; The liquid storage component (20) comprises a liquid storage tank (21), a liquid storage cover (22) and an ultrasonic vibration device (23); the liquid storage tank (21) is used to store the polymer solution; the liquid storage cover (22) is used to seal the top of the liquid storage tank (21) to ensure the formation of a negative pressure space; the ultrasonic vibration device (23) is a plurality of devices disposed around the liquid storage tank (21) to provide ultrasonic vibration to disperse large bubbles transported by the bubble component (10) into small bubbles; The stretching assembly (30) comprises an air compressor (31), a pressure regulating valve (32) and a gas delivery pipeline (33), wherein the air compressor (31) is used to generate high-pressure air; the pressure regulating valve (32) is used to adjust the gas pressure of the air compressor (31); and the gas delivery pipeline (33) is used to transport high-pressure air to stretch the polymer solution and bubbles; The flow diversion component (40) comprises a speed controller (41), a motor (42) and a guide wheel (43), wherein the speed controller (41) is used to control the speed of the motor (42); the motor (42) is used to drive the guide wheel (43) to rotate, and the guide wheel (43) is used to rotate and extrude the bubble transport hose.

2. The ultrasonic-assisted liquid-jet bubble spinning device according to claim 1, characterized in that: The receiving assembly (50) comprises a transmission wheel (51), a receiving net curtain (52), a fixing device (53) and a base (54); the transmission wheel (51) is used to drive the receiving net curtain (52) to rotate; the receiving net curtain (52) is used to receive nanofibers; the fixing device (53) is used to fix the transmission wheel (51) and the receiving net curtain (52); and the base (54) is used to support the entire receiving assembly (50).

3. The ultrasonic-assisted liquid-jet bubble spinning device according to claim 1, characterized in that: The guide wheel (43) is a three-way guide wheel having three external wheel groups; the external wheel groups are rotatable.

4. The ultrasonic-assisted liquid-jet bubble spinning device according to claim 1, characterized in that: The liquid storage cover (22) has a sealing strip inside.

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