CN101126179A - Superfine polymer fiber high-speed air-blown electrospinning compound preparation method and device - Google Patents

Abstract

The composite preparation method and device of ultrafine polymer fiber high-speed air blowing electrostatic spinning of the present invention improve the electrostatic spinning speed through high-speed airflow. The air flow path and the solution path are separated by the casing, the central capillary is the polymer solution channel, and the outer tube is the air flow channel. Under the action of a strong electric field, a jet of polymer solution is ejected from the droplet. On the one hand, the high-speed air flow ejected from the outer casing produces a siphon effect on the polymer solution in the central capillary, helping to overcome the surface tension of the droplets and accelerating the injection of the solution jet; The volatilization of the solvent and the movement speed of the jet to the other pole. The spinning speed of the present invention is more than 10 times higher than that of single electrospinning, and meanwhile, the surface of the formed nanofiber is smooth, and the diameter size and diameter distribution are similar to those of fibers prepared by single electrospinning.

Description

Superfine polymer fiber high-speed air-blown electrospinning compound preparation method and device

Field:

The invention belongs to a composite processing technology of high-speed air blowing electrostatic spinning. In the present invention, the charged fluid at the tip is simultaneously acted on by the high-speed airflow and the high-voltage electric field, so that it rapidly forms a charged jet and shoots to the other pole of the electric field. Under the synergy of the driving force of the electric field and the high-speed moving airflow, the charged jet moves rapidly to the nanofiber collector (the other pole of the electric field), the solvent evaporates rapidly, the diameter of the jet decreases rapidly, and the jet finally solidifies to form nanofibers with uniform diameter.

Background technique:

Electrospinning technology is a kind of charged polymer solution or melt to generate fine jets in an electrostatic field. During the rapid movement of this jet from one pole to another, the solvent volatilizes and the solute solidifies or the melt cools. And the processing method of curing to form polymer ultrafine fibers. The diameter of electrospun polymer microfibers covers a broad spectrum size range from 1 nanometer to several microns, and its length covers the range of several centimeters to several meters (depending on the shape and collection method of the fiber collection device). The one-dimensional nanomaterial characteristics of the length enable it to be directly used as a macroscopic structural material to form an electrospun ultrafine fiber nonwoven fabric. This electrospun ultrafine fiber non-woven fabric (non-woven fabric) is highly porous, with a pore size as small as a few nanometers, and has excellent filtration properties. Due to strength issues, it can only be used or is being developed for air intakes of various engines (from automobiles, tank engines to turbine plants) in combination with other supporting materials with appropriate strength, and to filter dust in fire protection, medical and military protection. , smoke, bacteria, and even viruses. On the other hand, due to the good hand feeling caused by the softness of small-diameter fibers and the good hygroscopicity caused by high specific surface area, electrospun polymer nanofibers have great potential to enter the comfortable clothing industry; in terms of aerospace, American scientists are In research, this highly porous, resulting in low density, electrospun polymer nanofiber cloth is used to make light sails that propel spacecraft in space.

Ordinary electrospinning technology uses a hollow nozzle nozzle, and the polymer solution or melt forms suspended semi-droplets on the hollow tip or needle, and the latter forms a Taylor cone under the action of a high-voltage electric field. Finally, the electric field force is in The sharp cone breaks through the liquid surface tension to generate a charged jet and shoots to the other pole to form ultra-fine fibers. In this way of preparing ultrafine fibers, the output of a single nozzle (or single needle) is less than 0.5 grams per hour (lower at low concentrations), which greatly limits the industrial development of electrospun ultrafine fibers.

Contents of the invention

The purpose of the present invention is to provide a composite preparation method and device for superfine polymer fiber high-speed air blowing electrostatic spinning.

The device for composite preparation of ultra-fine polymer fiber by high-speed air-blowing electrospinning comprises: a nozzle, a high-voltage power supply, a metal needle, a nozzle jacket in a tapered tubular shape, a polymer solution nozzle in the middle of the nozzle, and a metal nozzle in the center of the nozzle. Needle, the tail of the metal needle is connected to a high-voltage power supply, an air distribution valve is provided between the nozzle pipe and the nozzle jacket, and a high-pressure air outlet is provided on the side wall of the nozzle jacket, and the high-pressure air outlet is connected to the distribution valve and the nozzle pipe.

The composite preparation method of superfine polymer fiber high-speed air-blown electrostatic spinning of the present invention is characterized in that: the inner and outer sleeves are used to separate the gas path from the solution channel, the high-speed air flow is sprayed from the outer sleeve, and the polymer solution is mechanically thrust, Under the joint action of the high-speed airflow "siphon" and the driving force of the high-voltage electric field, it is ejected from the end of the central capillary to form a stable high-speed jet, which shoots to the other pole as a collector. During the movement of the jet from one pole to the other, the solvent evaporates and the jet solidifies to form polymer microfibers. The electric field strength used in this high-speed air-blown electrospinning composite processing technology is between 30 and 120kV/m, the gas flow rate at the spinneret is in the range of 100m/s to 500m/s, and the spinning liquid consumption of a single nozzle is between 0.1 to 1.0 ml/min, the diameter of the formed polymer ultrafine fiber is in the range of 50nm to 1500nm.

The present invention uses high-pressure airflow and high-voltage electric field to act together to spin, that is, high-pressure airflow is used to accelerate the speed of electrostatic spinning. The polymer solution forms a highly dispersed jet under the joint action of high-pressure airflow and high-voltage electric field, and shoots to the other pole of the electric field. Advantages of the present invention:

The equipment used in the electrospinning process is simple and easy to operate, and can be used for electrospinning and blending of various polymer solutions, and even polymer solutions that are difficult to directly electrospin can be electrospun by this method. The technique can dramatically speed up electrospinning, which is nearly 10 times faster than electrospinning alone. At the same time, the nanofibers are formed without beads and have uniform diameters, and the diameters of the prepared nanofibers are between 1500-50nm.

Description of drawings

Figure 1 is a schematic diagram of the device for composite preparation of ultrafine polymer fibers by high-speed air-blown electrospinning

Figure 2 is the SEM photo of PAN nanofibers

Figure 3 is the SEM photo of PAA nanofibers

Figure 4 is the SEM photo of Nylon 4/6 nanofibers

Figure 5 is the SEM photo of PSA nanofibers

Figure 6 is the SEM photo of PLA nanofibers

Figure 7 is the SEM photo of PU nanofibers

specific embodiment

Example 1: A device for composite preparation of ultrafine polymer fibers by high-speed air-blowing electrospinning includes: nozzles, high-voltage power supplies, metal needles, and nozzle jackets are tapered tubes, and the middle part of the nozzles is provided with polymer solution nozzles 4, There is a metal needle 7 in the center of the nozzle 4, and the tail of the metal needle 7 is connected to the high-voltage power supply 2. There is an air uniform valve 6 between the nozzle 4 and the nozzle casing. The side wall of the nozzle casing is provided with a high-pressure air outlet 3 and a high-pressure air outlet 3 It is connected with the uniform gas valve and nozzle 4. The pipe wall between the jackets of the device prepared by high-speed air-blowing electrospinning of ultrafine polymer fibers separates the air flow and the polymer solution. A constant pressure is applied to the polymer solution, and the polymer solution flows out from the nozzle inner tube polymer solution nozzle 4 stably under the action of gravity or external pressure, and forms droplets at the outlet. The high-pressure airflow 5 is ejected from the periphery of the droplet, forming a "siphon" phenomenon and acting on the polymer droplet, thereby accelerating the outflow speed of the solution and the speed of the jet ejected from the droplet. The charged jet moves rapidly to the nanofiber collector, which is the other pole of the electric field, the solvent evaporates rapidly, the diameter of the jet decreases rapidly, and the jet finally solidifies to form nanofibers with uniform diameters. By adjusting the properties of the polymer solution, such as viscosity, conductivity, etc., the shape and diameter of nanofibers can be changed, and nanofibers with smooth surface and uniform diameter can be prepared.

The preparation method of example 2 polyacrylonitrile (PAN) spinning solution

Weigh 10g of PAN with an intrinsic viscosity of 2.3dl/g, add 90g N'N-dimethylacetamide (DMAc), control the solution mass concentration to be about 10%, add about 0.2% cetyltrimethyl Ammonium bromide (DEMAB) was used to increase the conductivity of the solution, and stirred at 100°C for 2 hours to form a uniform and transparent solution. The electric field strength of spinning is 50kV/m, the gas flow rate is 10L/min, the gas flow rate of the spinneret is 204m/s, the solution consumption (single nozzle) is 0.3ml/min, and the diameter of the nanofiber is 800-1500nm. The SEM photo of PAN nanofibers is shown in Figure 2.

The preparation method of example 3 polyamic acid (PAA) spinning solution

Take 50 g of the original PAA/DMAc solution with a synthetic concentration of about 15% and an intrinsic viscosity of 2.02dl/g, add 5 g of tetrahydrofuran (THF) to dilute to a total mass concentration of the solution of about 12%, and add about 0.2% of organic salt DEMAB was stirred at 0°C for 2 hours to form a uniform and transparent solution. The electric field strength of spinning is 60KV/m, the gas flow rate is 20L/min, the gas flow rate of the spinneret is 408m/s, the solution consumption (of a single nozzle) is 0.25ml/min, and the diameter of the nanofiber is 390-700nm. The SEM photo of PAA nanofibers is shown in Figure 3.

The preparation method of example 4Nylon 4/6 spinning solution

Weigh 20g of Nylon 4/6 with an intrinsic viscosity of 2.1dl/g, add 80g of formic acid, control the mass concentration of the solution to about 20%, add about 0.2% of organic salt DEMAB, and stir at room temperature for 8 hours to form a uniform Clear solution. The electric field strength of spinning is 65KV/m, the gas flow rate is 18L/min, the solution flow rate is 0.3ml/min, the diameter of the nanofiber is 100-180nm, and the SEM photo of Nylon 4/6 nanofiber is shown in Figure 4.

The preparation method of example 5 polysulfone aramid fiber (PSA) spinning solution

Take by weighing 20g of PSA with an intrinsic viscosity of 1.32dl/g, add 113.3g DMAc, control the mass concentration of the solution to be about 15%, add about 0.2% organic salt DEMAB, and stir for 8 hours at normal temperature to form a uniform and transparent solution. The electric field strength of spinning is 60KV/m, the air flow rate is 15L/min, the gas flow rate at the spinneret is 306m/s, the flow rate of the solution (single nozzle) is 0.25ml/min, and the diameter of the nanofiber is 100-450nm. The SEM photo of PSA nanofibers is shown in Figure 5.

The preparation method of example 6 polylactic acid (PLA) spinning solution

Weigh 10g of PLA with an intrinsic viscosity of 3.3-4.3dl/g, add 138g of chloroform, control the mass concentration of the solution to about 3.5%, add about 0.2% of organic salt DEMAB, and stir at room temperature for 8 hours to form Homogeneous and transparent solution. The electric field strength of spinning is 45KV/m, the gas flow rate is 10L/min, the gas flow rate of the spinneret is 204m/s, the solution consumption (of a single nozzle) is 0.3ml/min, and the diameter of the nanofiber is 500-850nm. The SEM photo of PLA nanofibers is shown in Figure 6.

The preparation method of example 7 polyurea (PU) spinning solution

Weigh 15g of PU with an intrinsic viscosity of 1.36dl/g, add 75g N'N-dimethylformamide (DMF) and 25g THF, control the total mass concentration of the solution to be about 15%, and add about 0.2% organic salt DEMAB was stirred at room temperature for 8 hours to form a uniform and transparent solution. The electric field strength of spinning is 60KV/m, the gas flow rate is 18L/min, the gas flow rate of the spinneret is 367m/s, the solution consumption (single nozzle) is 0.35ml/min, and the diameter of the nanofiber is 500-850nm. The SEM photo of PU nanofibers is shown in Figure 7.

Claims (2)

1. the device of the compound preparation of ultra-fine polymer fibre high-speed air-blowing static spinning, it is characterized in that: comprise nozzle, high voltage source (2), metal needle, the nozzle overcoat is a tapered tubular, the nozzle middle part is provided with polymer solution jet pipe (4), jet pipe 4 central authorities are provided with metal needle (7), metal needle (7) afterbody is connected with high voltage source (2), be provided with even air valve (6) between jet pipe 4 and the nozzle overcoat, the nozzle sleeve side wall is provided with high pressure draught outlet (3), high pressure draught outlet (3) and even air valve (6), jet pipe (4) UNICOM.

2. ultra-fine polymer fibre high-speed air-blowing static spinning composite preparation method, it is characterized in that: gas circuit and solution channel are separated with internal and external casing, high velocity air sprays from outer tube, polymer solution ejects from center capillary end under the acting in conjunction of mechanical thrust, high velocity air " siphon " and high voltage electric field driving force, form stable high-speed jet, directive is as another utmost point of gatherer.Jet from a utmost point to the motion process of another utmost point, solvent evaporates, jet solidifies, and forms polymer superfine fibre.The used electric-field intensity of this high-speed air-blowing static spinning Combined Machining Technology is between 30 to 120kV/m, the spinning nozzle gas flow rate is in 100m/s arrives the 500m/s scope, the spinning solution consumption of single shower nozzle is 0.1 to 1.0ml/min, and the diameter of the polymer superfine fibre that forms is in 50nm arrives the 1500nm scope.

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