Porous nanofiber batch preparation device and application method thereof
Technical Field
The invention belongs to the technical field of porous nanofibers, electrostatic spinning technology and textile machinery, and particularly relates to a batch preparation device for porous nanofibers and a using method of the batch preparation device.
Background
A series of surprising properties occur when polymer fiber diameters are reduced from the micrometer scale to the submicrometer scale or the nanometer scale. Such as very large volume specific surface area, the volume specific surface area of nanofibers is substantially 1000 times that of microfibers; surface functionalization can be flexibly performed; compared with other known material forms, the material shows excellent effects and mechanical properties, such as surface and interface effects, small-size effects, quantum tunneling effects, rigidity, tensile strength and the like. These outstanding properties make nanofibers the first choice for many important applications, with great potential for development in the fields of high efficiency filtration, biomedical applications, intelligent sensing, etc. Considering the feasibility of operation, stability and controllability (including fiber diameter and distribution), material range, time consumption, etc., electrostatic spinning technology becomes the only method capable of producing continuous polymer nanofibers. With the rise and rapid development of the science of the nano materials, the preparation of the nano fibers by using the electrostatic spinning method becomes a research hotspot of the engineering material science community.
The traditional single-needle electrostatic spinning device is simple and mainly comprises a high-voltage power supply system, a liquid supply system and a collection system. The liquid supply system comprises a micro-injection pump, a medical needle tube and a plain end metal needle head, the flow of the high polymer solution is controlled by the micro-injection pump, the anode of the high-voltage power supply is connected with the plain end metal needle head, and the collection system is a metal flat plate and is grounded. High voltage power supply voltage crescent, the liquid drop of metal syringe needle forms the taylor awl gradually, and when high voltage power supply voltage further increases, the electric field force can overcome effects such as surface tension, the viscous force of high polymer solution and can appear whip phenomenon and reach ground connection metal collection board after forming tiny sharp efflux, and at this in-process, the solvent volatilizees, and the high polymer solidification forms the nanofiber deposit on metal collection board.
The electrostatic spinning nano-fiber has high specific surface area, but the porous fiber has more advantages than the smooth fiber in the fields of catalysis, biology and adsorption. Chinese patent ZL 201110168799.1 discloses a method for preparing porous nano-fiber with high specific surface area, PEO/CHCl3Solutions and DMF/CHCl3The solution is mixed and stirred uniformly and then mixed and stirred uniformly with PAN/DMF solution, the nanofiber is obtained through traditional single-needle electrostatic spinning, the solution is soaked in warm water at the temperature of 70 ℃ for 10 minutes to remove PEO, and the porous nanofiber is obtained through vacuum drying for more than 4 hours, the porous nanofiber can be prepared by the method, but the operation process is complicated, and the preparation yield is low; chinese patent ZL 201110375234.0 discloses the preparation of porous nanoparticles of polymers by mixed phase separationThe method for preparing the polymer porous nanofiber comprises the steps of mixing a polymer, an additive and a solvent according to a certain proportion, heating and stirring until the polymer, the additive and the solvent are completely dissolved to form a transparent solution, carrying out electrostatic spinning on the solution, depositing nascent fibers in an ice water bath or a water bath with the temperature of 0-20 ℃, carrying out thermally induced phase separation and non-solvent induced phase separation, and extracting the residual solvent and the additive through aftertreatment to obtain the polymer porous nanofiber.
The yield of the nanofiber obtained by the traditional electrostatic spinning device is very low, the requirement of the nanofiber in the process of large-scale application is difficult to meet, the problem that the needle head of the single-needle electrostatic spinning device is easy to block exists, and the smooth operation of the nanofiber spinning process can be seriously influenced.
At present, electrostatic spinning nanofiber batch preparation devices have some reports at home and abroad. Chinese patent ZL200710036447.4 discloses an air-jet electrostatic spinning device, which forms bubbles on the free liquid surface of high polymer by introducing gas into the bottom of a liquid tank, and the bubbles form taylor cones and multiple jets under the action of electric field force to improve the yield of nano-fibers, but many bubble fragments with different shapes and sizes are stretched by the electric field force while the taylor cones formed by the bubbles break in the mechanism, resulting in wider diameter distribution of the fibers. The solvent on the free liquid surface of the larger high polymer is extremely easy to volatilize, and the spinning direction is limited; chinese patent ZL 201310032194.9 discloses an umbrella-shaped electrostatic spinning nozzle and an electrostatic spinning method, the method can realize batch preparation of nano fibers, but the free surface of the solution of the umbrella-shaped nozzle is in contact with the atmospheric environment, the solvent is extremely volatile, the spinning stability and the final nano fiber quality are affected, and the curvature of the solution at the edge of the free liquid level cannot be regulated; chinese patent ZL 201510278266.7 discloses an air-jet assisted multi-needle electrostatic spinning device, which can improve the yield of nanofibers in unit time, the spinning direction is not limited, but there is the easy shortcoming of blocking of needles, simultaneously, the arrangement mode of needles should consider the mutual influence between the electric fields after applying high-voltage static electricity, so the design of multi-needle electrostatic spinning device is comparatively loaded down with trivial details and complicated, is difficult to realize the narrow nanofiber product of mass production fiber diameter distribution. The inventor's chinese patent ZL 201710046822.7 discloses a spherical rotating brush type batch electrostatic spinning device and a method for using the same, which can realize spinning of spherical liquid film spinning solution, greatly improve the yield and diameter distribution control of nanofibers, but at present, porous nanofiber batch preparation is still lacking.
In the stage of preparing the spinning solution, a non-solvent system is mixed and stirred to hardly obtain a stable mixed solution, once stirring is stopped, the whole system develops towards the direction of similar phase agglomeration, and therefore, uniform and controllable porous nanofiber products are difficult to continuously prepare.
Disclosure of Invention
The invention aims to provide a device for preparing porous nanofibers in batches and a using method thereof, and solves the problems that the existing porous nanofibers are low in preparation yield, difficult in regulation and control of a porous nanofiber structure and difficult in industrial production.
In order to solve the above technical problem, the present invention provides a mass production apparatus for porous nanofibers, comprising: the porous nanofiber spinning device comprises a porous nanofiber spinning device, a spinning solution supply system and a pore-forming solvent supply system, and a porous nanofiber collecting device, wherein the spinning solution supply system and the pore-forming solvent supply system are respectively used for supplying spinning solution and a pore-forming solvent to the porous nanofiber spinning device; the porous nanofiber spinning device comprises a rotatable spherical spray head, a device used for enabling a pore-generating solvent to volatilize and then condense on the surface of the spherical spray head and further coating a layer of high polymer spinning solution on the surface of the spherical spray head, and a device used for forming jet flow on the surface of the spherical spray head and enabling the jet flow to fly to a porous nanofiber collecting device under the action of a high-voltage electrostatic field to form porous nanofibers.
Preferably, the spinning solution supply system comprises a spinning solution storage tank, a spinning solution peristaltic pump and a spinning solution guide pipe, wherein the spinning solution peristaltic pump is connected with the spinning solution storage tank and the spinning solution guide pipe, and the spinning solution guide pipe is connected with the porous nanofiber spinning device.
Preferably, the raw-pore solvent supply system comprises a raw-pore solvent liquid storage tank, a raw-pore solvent peristaltic pump and a raw-pore solvent liquid guide pipe, wherein the raw-pore solvent peristaltic pump is connected with the raw-pore solvent liquid storage tank and the raw-pore solvent liquid guide pipe, and the raw-pore solvent liquid guide pipe is connected with the porous nanofiber spinning device.
Preferably, the spinning solution reservoir, the spinning solution peristaltic pump, the spinning solution catheter, the raw pore solvent reservoir, the raw pore solvent peristaltic pump and the raw pore solvent catheter are all made of polytetrafluoroethylene.
Preferably, the device for volatilizing the porogen and condensing the porogen on the surface of the spherical nozzle and coating a layer of high polymer spinning solution on the surface of the spherical nozzle comprises a polytetrafluoroethylene insulation seat, a nozzle rotation control motor and an insulation transmission shaft, wherein the polytetrafluoroethylene insulation seat is provided with a solution tank to be spun and a porogen supply tank, the solution tank to be spun is connected with a spinning solution supply system and used for storing the spinning solution, the solution supply tank to be spun is connected with the porogen supply system and used for storing the porogen, one part of the spherical nozzle is arranged on the upper side of the solution supply tank and the other part is arranged in the solution tank to be spun, the spherical nozzle is connected with the insulation transmission shaft, the insulation transmission shaft is connected with the nozzle rotation control motor, the nozzle rotation control motor can drive the spherical nozzle to rotate through the insulation transmission shaft, the porogen in the porogen supply tank volatilizes and condenses on the surface of the spherical nozzle, the spherical nozzle is driven by the nozzle rotation control motor to rotate to the liquid tank to be spun, and the surface of the spherical nozzle is coated with a layer of high polymer spinning liquid.
More preferably, the device for forming the jet flow on the surface of the spherical nozzle and making the jet flow fly to the porous nanofiber collecting device under the action of the high-voltage electrostatic field to form the porous nanofiber comprises a high-voltage positive bearing interface and a high-voltage lead, wherein the high-voltage positive bearing interface is sleeved on the insulating transmission shaft, one end of the high-voltage positive bearing interface is connected with the positive electrode of the high-voltage generator, and the other end of the high-voltage positive bearing interface is reliably connected with the spherical nozzle through the high-voltage lead.
More preferably, the porous nanofiber collection apparatus is a cylindrical rotatable metal drum driven by a variable speed drive motor.
More preferably, the material of the rotary spherical nozzle is stainless steel or metal copper.
More preferably, the nozzle rotation control motor includes a PLC programming module that can set the rotation speed, torque and direction.
More preferably, the spinning solution supply system supplies the spinning solution through an insulated spinning solution peristaltic pump, the liquid supply speed is 0-10mL/min, and the spinning solution is pumped out of a spinning solution storage tank and enters a solution tank to be spun.
More preferably, the porogen solvent supply system supplies porogen solvent to the porogen solvent supply tank by an insulated porogen solvent peristaltic pump at a supply rate of 0-4 mL/min.
More preferably, the spinning solution supply system and the porogen solvent supply system can both control the temperature of the spinning solution and the porogen solvent to be-5 ℃ to 60 ℃.
More preferably, the voltage regulation range of the high voltage generator is 0-120 KV.
More preferably, the insulation transmission shaft is made of polytetrafluoroethylene and is arranged at the axis of the spherical nozzle.
More preferably, the rotating control motor is a motor with adjustable speed, the rotating speed of the motor is 0-20r/min, and the motor is controlled by a PLC programming module.
More preferably, the porous nanofiber collecting device is grounded or connected to the negative electrode of a high voltage generator.
More preferably, the diameter of the metal roller is 90mm-1200mm, and the rotating speed of the driving motor is 0-150 r/min.
The invention also provides a method for batch production of porous nanofibers by using the device for batch production of porous nanofibers, which is characterized by comprising the following steps:
step 1: grounding the metal roller, and adjusting the distance between the metal roller and the spherical spray head;
step 2: opening a driving motor of the metal roller and setting the rotating speed of the roller;
and step 3: opening a switch of the pore-forming solvent supply system, adjusting the temperature of the pore-forming solvent, and supplying the pore-forming solvent to a pore-forming solvent supply tank through an insulated pore-forming solvent peristaltic pump;
and 4, step 4: opening a switch of a spinning solution supply system, adjusting the temperature of spinning solution, and supplying the spinning solution to a solution tank to be spun through an insulated spinning solution peristaltic pump;
and 5: opening a driving motor of the spherical nozzle, setting a spinning rotation program, condensing a pore-forming solvent at a certain temperature on the surface of the spherical nozzle after the pore-forming solvent is volatilized, driving the spherical nozzle to rotate by a rotation control motor through an insulating transmission shaft, and coating a layer of high polymer spinning solution;
step 6: opening a high-voltage generator switch, and increasing the voltage to the required spinning voltage; a large amount of jet flow is generated at a liquid film of the spherical nozzle, the jet flow flies to the metal roller under the action of a high-voltage electrostatic field, the solvent is volatilized, and the jet flow is stretched, solidified and deposited on the metal roller to form a large amount of porous nano fibers.
Compared with the prior art, the invention has the beneficial effects that:
the invention relates to a porous nanofiber batch preparation device and a using method thereof. The invention has the advantages that a layer of very thin solvent is supplied on the surface of the spray head by adopting a raw pore solvent supply system through gas phase state solvent agglutination, the infiltration amount of the raw pore solvent is regulated and controlled through the temperature difference of the spinning solution and the raw pore solvent, the uniform injection of a trace amount of the raw pore solvent into jet flow in the free liquid level electrostatic spinning process can be realized, the regulation and control of the batch preparation process of the porous nanofiber are further realized, the technology is simple and easy to implement, and the method has great potential in the application fields of energy, filtration, biology and medical treatment.
Drawings
FIG. 1 is a schematic view of a batch manufacturing apparatus for porous nanofibers;
FIG. 2 is a schematic view of a liquid film on the surface of a spherical nozzle;
FIG. 3 is a schematic view of a jet of a ball-type sprinkler;
fig. 4 is a scanning electron microscope image of porous nanofibers prepared by the porous nanofiber batch apparatus.
Detailed Description
The invention will be further illustrated with reference to the following specific examples. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Further, it should be understood that various changes or modifications of the present invention may be made by those skilled in the art after reading the teaching of the present invention, and such equivalents may fall within the scope of the present invention as defined in the appended claims.
Example 1
As shown in fig. 1, the apparatus for mass-producing porous nanofibers according to the present invention includes a porous nanofiber spinning apparatus, a spinning solution supply system and a pore-forming solvent supply system for supplying a spinning solution and a pore-forming solvent to the porous nanofiber spinning apparatus, respectively, and a porous nanofiber collecting apparatus for collecting porous nanofibers.
The porous nanofiber spinning device comprises a rotatable spherical spray nozzle 15, a device which is used for enabling a pore-generating solvent to be condensed on the surface of the spherical spray nozzle 15 after being volatilized, and coating a layer of high polymer spinning solution 22 on the surface of the spherical spray nozzle 15, and a device which is used for forming jet flow on the surface of the spherical spray nozzle 15 and enabling the jet flow to fly to a porous nanofiber collecting device under the action of a high-voltage electrostatic field to form porous nanofibers.
The spinning solution supply system is used for supplying high polymer spinning solution 22 and comprises a spinning solution storage tank 23, a spinning solution peristaltic pump 20 and a spinning solution guide pipe 17, the spinning solution peristaltic pump 20 is connected with the spinning solution storage tank 23 and the spinning solution guide pipe 17, and the spinning solution guide pipe 17 is connected with a porous nanofiber spinning device.
The pore-generating solvent supply system supplies a layer of very thin pore-generating solvent 2 on the surface of the spherical nozzle 15 through gas phase solvent agglutination, and comprises a pore-generating solvent liquid storage tank 1, a pore-generating solvent peristaltic pump 21 and a pore-generating solvent liquid guide pipe 3, wherein the pore-generating solvent peristaltic pump 21 is connected with the pore-generating solvent liquid storage tank 1 and the pore-generating solvent liquid guide pipe 3, and the pore-generating solvent liquid guide pipe 3 is connected with the porous nanofiber spinning device.
The spinning solution reservoir 23, the spinning solution peristaltic pump 20, the spinning solution guide tube 17, the raw pore solvent reservoir 1, the raw pore solvent peristaltic pump 21 and the raw pore solvent guide tube 3 are all made of polytetrafluoroethylene.
The device for condensing the pore-forming solvent on the surface of the spherical nozzle 15 after volatilization and coating a layer of high polymer spinning solution 22 on the surface of the spherical nozzle 15 comprises a polytetrafluoroethylene insulating base 19, a nozzle rotation control motor 7 and an insulating transmission shaft 6, wherein the polytetrafluoroethylene insulating base 19 is provided with a solution tank 16 to be spun and a pore-forming solvent supply tank 18, the solution tank 16 to be spun is connected with a spinning solution supply system and used for storing the spinning solution, the pore-forming solvent supply tank 18 is connected with the pore-forming solvent supply system and used for storing the pore-forming solvent, one part of the spherical nozzle 15 is arranged at the upper side of the pore-forming solvent supply tank 18, the other part of the spherical nozzle 15 is arranged in the solution tank 16 to be spun, the rotating spherical nozzle 15 is connected with the insulating transmission shaft 6, the insulating transmission shaft 6 is connected with the nozzle rotation control motor 7, and the nozzle rotation control motor 7 can drive the spherical, the pore-forming solvent in the pore-forming solvent supply tank 18 is evaporated and then condensed on the surface of the spherical nozzle 15, the spherical nozzle 15 is driven by the nozzle rotation control motor 7 to rotate into the solution tank 18 to be spun, and the surface of the spherical nozzle 15 is coated with a layer of high polymer spinning solution 22, as shown in fig. 2.
The device for forming jet flow on the surface of the spherical nozzle 15 and enabling the jet flow to fly to the porous nanofiber collecting device under the action of the high-voltage electrostatic field to form porous nanofiber comprises a high-voltage positive bearing interface 8 and a high-voltage lead 9, wherein the high-voltage positive bearing interface 8 is sleeved on an insulating transmission shaft 6, one end of the high-voltage positive bearing interface 8 is connected with the positive electrode of the high-voltage generator 4, and the other end of the high-voltage positive bearing interface 8 is reliably connected with the spherical nozzle 15 through the high-voltage lead 9.
The porous nanofiber collecting device is a cylindrical metal roller 11 capable of rotating and is driven by a speed-adjustable driving motor 10.
The material of the spherical nozzle 15 is stainless steel or metal copper. The nozzle rotation control motor 7 comprises a PLC programming module and can set rotation speed, torque and direction. The spinning solution supply system supplies the spinning solution through an insulated spinning solution peristaltic pump 20, the liquid supply speed is 0-10mL/min, and the spinning solution is pumped out of a spinning solution storage tank 23 and enters a solution tank 16 to be spun. The pore-forming solvent supply system supplies a pore-forming solvent 22 to the pore-forming solvent supply tank 18 through an insulated pore-forming solvent peristaltic pump 21 at a supply rate of 0-4 mL/min. The spinning solution supply system and the pore-forming solvent supply system can control the temperatures of the spinning solution and the pore-forming solvent to be-5 ℃ to 60 ℃.
The voltage regulating range of the high voltage generator 4 is 0-120 KV. The insulating transmission shaft 6 is made of polytetrafluoroethylene and is arranged at the axis of the spherical nozzle 15. The rotating control motor 7 is a motor with adjustable speed, the rotating speed of the motor is 0-20r/min, and the rotating control motor is controlled by a PLC programming module. The porous nanofiber collecting device is grounded 13, the diameter of the metal roller 11 is 90mm-1200mm, and the rotating speed of the driving motor 10 is 0-150 r/min.
Porous nanofibers were prepared using a high polymer solution prepared from Polyacrylonitrile (PAN) (molecular weight (86000)) N-N Dimethylformamide (DMF) and chloroform solvent. Preparing PAN/DMF high polymer spinning solution with the mass fraction of 12%. The pore-forming solvent 22 is chloroform.
The method for carrying out the batch production of the porous nanofibers by using the device for preparing the porous nanofibers in batches comprises the following steps: grounding 13 the metal roller 11, and adjusting the distance between the metal roller 11 and the spherical spray head 15 to be 18 cm; opening a driving motor 10 of a metal roller 11, and setting the rotating speed of the roller to be 60 r/min; opening a switch of the porogen supply system, adjusting the temperature of the porogen to room temperature, and supplying the porogen 2 to a porogen supply tank 18 through an insulated porogen peristaltic pump 21; opening a switch of a spinning solution supply system, adjusting the temperature of the spinning solution to room temperature, and supplying the spinning solution to a solution tank 16 to be spun through an insulated spinning solution peristaltic pump 20; opening a driving motor 7 of the spherical nozzle 15, setting a spinning rotation program to be 2.5r/min clockwise, volatilizing a pore-forming solvent 18 at a certain temperature, condensing the volatilized solvent on the surface of the spherical nozzle 15, driving the spherical nozzle 15 to rotate by a rotation control motor 7 through an insulating transmission shaft 6, and coating a layer of high polymer spinning solution 22; turning on a switch of the high-voltage generator 4, and slowly increasing the voltage to 60 KV; as shown in fig. 3, a large number of jets 14 are generated at the liquid film of the spherical nozzle 15; the jet 14 flies to the metal roller 11 under the action of the high-voltage electrostatic field, the solvent is volatilized, and the jet is stretched, solidified and deposited on the metal roller 11 to form a large number of porous nanofibers 12, as shown in fig. 4.
Example 2
The porous nanofiber is prepared by adopting a high polymer solution prepared from Polyacrylonitrile (PAN) and N-N Dimethylformamide (DMF) and a trichloromethane solvent. Preparing 15 percent of PAN/DMF high polymer spinning solution by mass percent. The pore-forming solvent 22 is chloroform.
The method for mass production of porous nanofibers using the porous nanofiber mass production apparatus in example 1 includes: grounding 13 the metal roller 11, and adjusting the distance between the metal roller 11 and the spherical spray head 15 to be 20 cm; opening a driving motor 10 of a metal roller 11, and setting the rotating speed of the roller to be 90 r/min; opening a switch of the porogen supply system, adjusting the temperature of the porogen to room temperature, and supplying the porogen 2 to a porogen supply tank 18 through an insulated porogen peristaltic pump 21; opening a switch of a spinning solution supply system, adjusting the temperature of the spinning solution to room temperature, and supplying the spinning solution to a solution tank 16 to be spun through an insulated spinning solution peristaltic pump 20; opening a driving motor 7 of the spherical nozzle 15, setting a spinning rotation program to be 4r/min clockwise, volatilizing a pore-forming solvent 18 at a certain temperature, condensing the volatilized solvent on the surface of the spherical nozzle 15, driving the spherical nozzle 15 to rotate by a rotation control motor 7 through an insulating transmission shaft 6, and coating a layer of high polymer spinning solution 22; turning on a switch of the high-voltage generator 4, and slowly increasing the voltage to 80 KV; a large number of jets 14 are generated at the liquid film of the spherical nozzle 15; the jet flow 14 flies to the metal roller 11 under the action of a high-voltage electrostatic field, the solvent is volatilized, and the jet flow is stretched, solidified and deposited on the metal roller 11 to form a large number of porous nanofibers 12.
Example 3
Next, porous nanofibers were prepared using a high polymer solution prepared from Polystyrene (PS) and Tetrahydrofuran (THF) and a cyclohexane solvent. The mass fraction of PS/THF high polymer spinning solution is 28%, and the pore-forming solvent 22 is cyclohexane.
The method for mass production of porous nanofibers using the porous nanofiber mass production apparatus in example 1 includes: grounding 13 the metal roller 11, and adjusting the distance between the metal roller 11 and the spherical spray head 15 to be 18 cm; opening a driving motor 10 of a metal roller 11, and setting the rotating speed of the roller to be 60 r/min; opening a switch of the porogen supply system, adjusting the temperature of the porogen to room temperature, and supplying the porogen 2 to a porogen supply tank 18 through an insulated porogen peristaltic pump 21; opening a switch of a spinning solution supply system, adjusting the temperature of the spinning solution to room temperature, and supplying the spinning solution to a solution tank 16 to be spun through an insulated spinning solution peristaltic pump 20; opening a driving motor 7 of the spherical nozzle 15, setting a spinning rotation program to be 2.5r/min clockwise, volatilizing a pore-forming solvent 18 at a certain temperature, condensing the volatilized solvent on the surface of the spherical nozzle 15, driving the spherical nozzle 15 to rotate by a rotation control motor 7 through an insulating transmission shaft 6, and coating a layer of high polymer spinning solution 22; turning on a switch of the high-voltage generator 4, and slowly increasing the voltage to 70 KV; a large number of jets 14 are generated at the liquid film of the spherical nozzle 15; the jet flow 14 flies to the metal roller 11 under the action of a high-voltage electrostatic field, the solvent is volatilized, and the jet flow is stretched, solidified and deposited on the metal roller 11 to form a large number of porous nanofibers 12.