Device for preparing three-dimensional fiber aerogel through airflow turbulence assisted centrifugal spinning

Abstract

The invention discloses equipment for preparing three-dimensional fiber aerogel through airflow turbulence assisted centrifugal spinning, and belongs to the technical field of centrifugal spinning.The equipment comprises a cross beam support, a high-speed centrifugal module, an airflow assisting module, a liquid supply module and a continuous collection module, and the high-speed centrifugal module comprises a high-speed motor, a ceramic bearing and a needleless spinning cup; the high-speed motor provides centrifugal force needed by spinning, spinning holes are formed in the cup wall of the needleless spinning cup, the continuous collecting module is located below the needleless spinning cup, the air compressor is communicated with the air path outlet rotating rod through the air path channel, and during centrifugal spinning, the intelligent injection pump pumps spinning liquid in the injector into the needleless spinning cup through the liquid conveying pipe; the air path outlet rotating rod ejects stable air flow to form turbulent flow, the fibers thrown out through the spinning holes are further stretched and wound under the turbulent flow effect, and finally the fibers are deposited in a three-dimensional structure and fall onto the continuous collecting module to be continuously collected. A high-voltage electric field and high temperature do not need to be applied, and the production efficiency is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of centrifugal spinning, and in particular relates to a device for preparing three-dimensional fiber aerogel by centrifugal spinning assisted by airflow turbulence. Background Art

[0002] At present, the most widely used fiber aerogel preparation methods are electrospinning and melt spinning. The electrospinning method refers to the spinning solution being applied to a certain propulsion speed under the action of a high-voltage electric field. The small droplets formed at the needle tip are diffracted in the form of a Taylor cone under the action of the electric field force to form a jet. In this process, the solvent evaporates and the fiber is solidified. Due to its advantages such as effective reduction of fiber diameter and regulation of fiber morphology, researchers have successfully prepared fiber aerogels for catalysis, biology, thermal insulation and other fields through electrospinning. However, the production efficiency of electrospinning is low, and the preparation process requires a high-voltage electrostatic field, which has certain production safety risks and is difficult to meet industrial production. The melt spinning method refers to the melt being applied to a certain centrifugal force under the action of high-speed rotation. When the centrifugal force is greater than the viscosity, adsorption and surface tension of the melt, the melt is stretched and solidified into fibers. Melt spinning is widely used in actual production due to its high production efficiency and the lack of an external electric field. However, melt spinning requires heating the material to a high temperature and liquefying it, which will result in high energy consumption, causing environmental pollution and energy waste. At the same time, as the operating temperature of ceramic fiber aerogels continues to increase, high-melting-point ceramic sources are difficult to be heated electrically to a spinnable molten state, which in turn limits the preparation of high-temperature ceramic fiber aerogels.

[0003] In contrast, the solution method combined with centrifugal spinning as a new fiber aerogel preparation technology has attracted much attention because it does not require a high-voltage electric field for electrospinning or a high-temperature furnace for melt spinning. Solution centrifugal spinning uses the centrifugal force generated by a high-speed spinning head to squeeze the spinning solution out of the spinning needle or spinning hole to form a jet. The spinning solution evaporates in the air under the action of inertia and is pulled into fibers. However, most existing technologies have problems such as the inability to continuously supply liquid and the inability to continuously collect in annular receiving.

[0004] Since the fibers need to be thrown out from the spinning needle or spinning hole at the edge of the spinning head under the action of centrifugal force, most of the collection devices are arranged with a ring-shaped collection baffle or collection rod, which makes it difficult to collect the fibers continuously and the collected fibers are in a ring shape and cannot be formed in one go. In addition, the deposition direction of the fibers spun by the existing centrifugal spinning equipment is consistent with the direction of the centrifugal force, and the fibers have obvious orientation, which makes it impossible to form a three-dimensional aerogel structure in one go.

[0005] Solution centrifugal spinning often requires a higher rotation speed than melt spinning, and the high rotation speed also brings limitations on the radius size of the spinning head. It also requires a higher concentricity between the spinning head and the motor rotor, otherwise it will cause catastrophic problems.

[0006] China Publication No.: CN220746155U discloses a hollow shaft centrifugal spinning device, which discloses the connection method between the spinning cup and the motor, ensuring the concentricity and safety of the equipment under high-speed rotation, but still has problems such as inability to continuously supply liquid and inability to continuously collect liquid.

[0007] Therefore, it is urgent to develop a high-speed centrifugal spinning equipment for preparing three-dimensional fiber aerogels that can achieve continuous liquid supply and continuous collection. Summary of the invention

[0008] Based on the above shortcomings, the purpose of the present invention is to provide a device for preparing three-dimensional fiber aerogel by centrifugal spinning assisted by air turbulence.

[0009] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present invention is as follows: an airflow turbulence-assisted centrifugal spinning device for preparing three-dimensional fiber aerogels, comprising a crossbeam bracket, a high-speed centrifugal module, an airflow auxiliary module, a liquid supply module and a continuous collection module, the high-speed centrifugal module comprising a high-speed motor, a ceramic bearing, and a needleless spinning cup, the high-speed motor is invertedly mounted on the crossbeam of the bracket, the output shaft of the high-speed motor is connected to the needleless spinning cup through a ceramic bearing to provide it with the centrifugal force required for spinning, the needleless spinning cup is a concave-shaped round-bottomed hollow cup, and spinning holes of different shapes and diameters are arranged on the cup wall according to the spinning requirements, the continuous collection module is located below the needleless spinning cup, the airflow auxiliary module comprises an air compressor with an air heating device and an air outlet rotary rod, the air compressor provides dry compressed air with a continuous and controllable flow rate, and the air compressor passes The air path channel is connected to the air path outlet rotary rod, the air path outlet rotary rod is fixedly connected to the side wall of the bracket, the extension line direction of the air path outlet rotary rod intersects with the radial extension line of the needleless spinning cup, and the intersection angle is 135°; the liquid supply module includes an intelligent injection pump and a syringe, the upper port of the infusion tube is connected to the syringe, and the lower port thereof extends to the bottom surface of the needleless spinning cup and is in virtual contact with the bottom surface; during centrifugal spinning, the needleless spinning cup rotates at a high speed driven by a high-speed motor, and the intelligent injection pump pumps the spinning liquid in the syringe into the needleless spinning cup through the infusion tube, and then infiltrates into the inner wall of the needleless spinning cup and is thrown out from the spinning hole, the air path outlet rotary rod shoots a stable airflow into the cavity of the needleless spinning cup and forms turbulence in the space, and the fibers thrown out through the spinning hole are further stretched and entangled by the turbulent flow, and finally deposited in a three-dimensional structure and fall onto the continuous collection module for continuous collection.

[0010] Furthermore, the side wall of the needleless spinning cup is provided with 2-6 spinning holes, the diameter of the spinning holes is 0.1-0.5 mm, and the diameter of the spinning cup is 4-10 cm.

[0011] Furthermore, the jet velocity of the air outlet rotary rod is 0-10m / s.

[0012] Furthermore, the speed of the high-speed motor reaches 10000 rpm.

[0013] Another object of the present invention is to provide a method for spinning continuous three-dimensional fiber aerogel, using the above-mentioned device, comprising the following steps:

[0014] S1. Centrifugal spinning solution preparation: dissolving the polymer or ceramic source in a suitable solvent to obtain a spinnable solution with good fluidity;

[0015] S2, inject the spinning solution into the syringe, and the intelligent injection pump controls the step speed to continuously inject the spinning solution into the needle-free spinning cup;

[0016] S3. Turn on the high-speed motor to make the needle-free spinning cup rotate at high speed, turn on the airflow auxiliary module and adjust the flow rate, the spinning liquid is continuously thrown out, and the spinning liquid is pulled into fibers under the physical field of vortex and centrifugal force coupling, and disorderly entangled into a three-dimensional structure; under the action of airflow turbulence, the spun fibers are deposited downward in a three-dimensional structure and fall onto the continuous collection module for continuous collection under the action of airflow turbulence.

[0017] The present invention has the following beneficial effects and advantages:

[0018] (1) Air flow turbulence is used to assist spinning. In addition to the centrifugal force field and cyclone field generated by the high-speed rotation of the spinning head in normal centrifugal spinning, a second-phase turbulent field is introduced, so that the fibers are more disorderly entangled under the action of multi-physical fields, and secondary traction is achieved to form a fiber aerogel with a three-dimensional structure.

[0019] (2) Spinning is carried out from top to bottom, and the air flow turbulence is assisted to collect the fibers in a directional manner. Combined with the continuous production and preparation with a conveyor belt, the problem of the equipment being unable to collect continuously due to the annular collection and the fiber morphology being annular is solved.

[0020] (3) Liquid is continuously supplied to the spinning cup through an infusion hose. The spinning liquid flows out from the port of the infusion tube and infiltrates the lower wall of the spinning cup. The spinning liquid is pulled to the outside on the high-speed rotating cup wall and obtains a certain initial jet velocity, and is finally thrown out from the spinning hole. The driving force for the spinning liquid to be thrown out into fibers is not only the centrifugal force in the tangential direction, but also the initial jet velocity along the spinning hole direction. Therefore, under the action of the same centrifugal force, the fiber can be stretched into fibers more effectively and fully. At the same time, the continuous pumping of the spinning liquid is realized during the centrifugal spinning process, so that the centrifugal spinning equipment can be used for industrial continuous large-scale production.

[0021] (5) The present invention does not require the application of a high voltage electric field or a high temperature, and can safely prepare fiber aerogels with three-dimensional structures in large quantities in a continuous manner, thereby improving production efficiency and having the advantage of a simple device structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a simplified structural diagram of the device of the present invention;

[0023] Figure 2 This is a schematic top view of the structure of the needle-free spinning cup of the present invention;

[0024] Figure 3 This is a schematic diagram of the front view of the needleless spinning cup of the present invention;

[0025] Figure 4 It is a schematic diagram of multi-physics field computational fluid dynamics wind field simulation of the present invention;

[0026] Figure 5 These are electron microscope photos of the prepared zirconia fiber aerogel, (a) electron microscope photo of the three-dimensional entanglement of the prepared aerogel fibers, and (b) electron microscope photo of the prepared aerogel single fiber.

[0027] Figure numerals: 1-high-speed motor; 2-needleless spinning cup; 21-spinning hole; 4-gas outlet rotary rod; 5-continuous collection module; 12-ceramic bearing; 31-intelligent injection pump; 32-syringe; 33-infusion tube. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0029] Example 1

[0030] like Figure 1-3As shown, an airflow turbulence-assisted centrifugal spinning device for preparing three-dimensional fiber aerogels comprises a crossbeam support, a high-speed centrifugal module, an airflow auxiliary module, a liquid supply module and a continuous collection module 5, wherein the high-speed centrifugal module comprises a high-speed motor 1, a ceramic bearing 12 and a needleless spinning cup 2, wherein the high-speed motor 1 is invertedly mounted on the crossbeam of the support and the output shaft of the high-speed motor 1 is adjusted to be in a vertical state, wherein the output shaft of the high-speed motor 1 is connected to the needleless spinning cup 2 through a ceramic bearing 12 to provide the centrifugal force required for spinning, wherein the needleless spinning cup 2 is a concave-shaped round-bottomed hollow cup, wherein spinning holes 21 of different shapes and diameters are arranged on the cup wall according to the spinning requirements, wherein the continuous collection module is located below the needleless spinning cup 21, and the airflow auxiliary module comprises an air compressor with an air heating device and an air outlet vortex Rod 4, the air compressor provides dry compressed air with a continuous and controllable flow rate, the air compressor is connected to the air outlet rotary rod 4 through the air path channel, the air outlet rotary rod 4 is fixedly connected to the side wall of the bracket, the extension line direction of the air outlet rotary rod 4 intersects with the radial extension line of the needleless spinning cup 2, and the intersection angle is 135°; the liquid supply module includes an intelligent injection pump 31 and a syringe 32, the upper port of the infusion tube 33 is connected to the syringe 32, and the lower port thereof extends to the bottom surface of the needleless spinning cup 2 and is in virtual contact with the bottom surface; during centrifugal spinning, the needleless spinning cup 2 rotates at a high speed driven by the high-speed motor 1, and the intelligent injection pump 31 pumps the spinning solution in the syringe 32 into the needleless spinning cup 2 through the infusion tube 33, and then infiltrates into the inner wall of the needleless spinning cup 2 and is thrown out from the spinning hole 21, such as Figure 4 As shown, the air outlet rotary rod 4 emits a stable airflow into the cavity of the needle-free spinning cup 2 and forms turbulence in the space. The fibers thrown out through the spinning hole 21 are further stretched and entangled by the turbulence, and finally deposited in a three-dimensional structure and fall onto the continuous collection module 5 for continuous collection, which effectively solves the problem that it is difficult to prepare aerogel with a three-dimensional structure under the action of centrifugal force alone and the spun fibers are ring-shaped and difficult to be continuously received.

[0031] The needle-free spinning cup 2 described in this embodiment is made of hardened aluminum, and has a "concave" shape in macroscopic view. The top is a radial plane structure with a central through hole to prevent the spinning liquid from splashing due to excessive pump speed and centrifugal force; its side wall is evenly spaced with spinning holes 21, the number is 2-6, and the hole diameter is 0.1-0.5mm.

[0032] Example 2

[0033] This embodiment uses the equipment of embodiment 1 to obtain a method for spinning continuous three-dimensional fiber aerogel, and the steps are as follows:

[0034] (1) According to the ratio of zirconium carbonate basic carbonate: glacial acetic acid: yttrium nitrate hexahydrate = 1: (1-2.5): 0.02, 100 g of zirconium carbonate basic carbonate, 50 g of glacial acetic acid, and 3.98 g of yttrium nitrate hexahydrate were weighed into a beaker, and an appropriate amount of polymer spinning aid was added. The mixture was stirred in a water bath at 60° C. until the solution was completely clarified to form a polyhydroxy zirconium oxide spinning solution.

[0035] (2) 50 ml of the prepared spinning solution is placed in a syringe and installed on an intelligent syringe pump, which is set to pump at a speed of 5 ml / min.

[0036] (3) The spinning speed is set to 10000 rpm, the spinning cup diameter is 8 cm, the spinning aperture is 0.3 mm, the receiving distance is 30 cm, and the conveying speed of the collecting device is 0.2 m / min. The high-speed motor and the intelligent injection pump are turned on, and the polyhydroxy zirconium oxide precursor fiber is collected by the conveyor belt of the continuous collection module, and finally the zirconium oxide fiber is obtained by ceramic crystallization treatment.

[0037] The electron microscope photo of the zirconia fiber prepared in this example is shown in Figure 5 As shown, the zirconia fiber prepared in this embodiment has a good three-dimensional structure, good fiber continuity, and a uniform diameter distribution between 1.5-2.5 μm.

Claims

1. An airflow turbulence-assisted centrifugal spinning device for preparing three-dimensional fiber aerogels, comprising a beam support, a high-speed centrifugal module, an airflow auxiliary module, a liquid supply module and a continuous collection module, characterized in that: The high-speed centrifugal module includes a high-speed motor, a ceramic bearing, and a needle-free spinning cup. The high-speed motor is inverted and installed on the crossbeam of the bracket. The output shaft of the high-speed motor is connected to the needle-free spinning cup through a ceramic bearing to provide it with the centrifugal force required for spinning. The needle-free spinning cup is a hollow cup with a concave bottom and a round bottom. Spinning holes of different shapes and diameters are arranged on the cup wall according to the spinning requirements. The continuous collection module is located below the needle-free spinning cup. The airflow auxiliary module includes an air compressor with an air heating device and an air outlet rotary rod. The air compressor provides dry compressed air with a continuous and controllable flow rate. The air compressor is connected to the air outlet rotary rod through an air channel. The air outlet rotary rod is fixedly connected to the side wall of the bracket. The extension line direction of the air outlet rotary rod intersects with the radial extension line of the needleless spinning cup, and the intersection angle is 135°; the liquid supply module includes an intelligent injection pump and a syringe, the upper port of the infusion tube is connected to the syringe, and the lower port thereof extends to the bottom surface of the needleless spinning cup and is in virtual contact with the bottom surface of the needleless spinning cup; during centrifugal spinning, the needleless spinning cup rotates at high speed driven by the high-speed motor, and the intelligent injection pump pumps the spinning liquid in the syringe into the needleless spinning cup through the infusion tube, and then infiltrates into the inner wall of the needleless spinning cup and is thrown out from the spinning hole. The air outlet rotary rod shoots a stable airflow into the cavity of the needleless spinning cup and forms turbulence in the space. The fibers thrown out through the spinning hole are further stretched and entangled by the turbulent flow, and finally deposited in a three-dimensional structure and fall onto the continuous collection module for continuous collection.

2. The device for preparing three-dimensional fiber aerogel by centrifugal spinning assisted by air turbulence according to claim 1, characterized in that: The side wall of the needleless spinning cup is provided with 2-6 spinning holes, the diameter of the spinning holes is 0.1-0.5 mm, and the diameter of the spinning cup is 4-10 cm.

3. The device for preparing three-dimensional fiber aerogel by centrifugal spinning assisted by air turbulence according to claim 1, characterized in that: The jet velocity of the rotary rod at the gas outlet is 0-10m / s.

4. The device for preparing three-dimensional fiber aerogel by centrifugal spinning assisted by air turbulence according to claim 1, characterized in that: The speed of the high-speed motor reaches 10000 rpm.

5. A method for continuous three-dimensional fiber aerogel spinning obtained by the device for preparing three-dimensional fiber aerogel by centrifugal spinning assisted by airflow turbulence according to any one of claims 1 to 4, characterized in that: The steps include: S1. Centrifugal spinning solution preparation: dissolving the polymer or ceramic source in a suitable solvent to obtain a spinnable solution with good fluidity; S2, inject the spinning solution into the syringe, and the intelligent injection pump controls the step speed to continuously inject the spinning solution into the needle-free spinning cup; S3. Turn on the high-speed motor to make the needle-free spinning cup rotate at high speed, turn on the airflow auxiliary module and adjust the flow rate, the spinning liquid is continuously thrown out, and the spinning liquid is pulled into fibers under the physical field of vortex and centrifugal force coupling, and disorderly entangled into a three-dimensional structure; under the action of airflow turbulence, the spun fibers are deposited downward in a three-dimensional structure and fall onto the continuous collection module for continuous collection under the action of airflow turbulence.

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