CN101328618B - Electrostatic spinning machine with special reticulate pattern electrode and application method thereof - Google Patents

Abstract

The invention relates to a high-efficiency electrostatic spinning film-making device capable of controlling the orientation of nano fibers, in particular to an electrostatic spinning machine with a special reticulate pattern electrode and a method for preparing a high-strength nano fiber film by applying the electrostatic spinning machine. The invention changes the common design concept of metal flat plate or metal roller electrodes in the common electrostatic spinning device, and the special mesh copper electrode is matched with the high-efficiency multi-needle nozzle to design a small electrostatic spinning machine to prepare the high-strength nanofiber film capable of controlling the orientation of the nanofibers.

Description

Electrospinning machine with special textured electrodes and method of application thereof

technical field

The invention relates to a high-efficiency electrospinning film-making device capable of controlling the orientation of nanofibers, in particular to an electrospinning machine with special mesh electrodes and a method for preparing high-strength nanofiber films using the electrospinning machine.

technical background

Electrospinning is an important method for preparing nanofibers and functional nanofiber films. At present, the research of electrospinning mainly focuses on basic research, and the simple device of single-needle nozzle and metal plate (or roller) receiving electrode is used to prepare various nanowires and nanocomposites.

The strength of nanofibers is usually high, but the strength of nanofiber membranes prepared by electrospinning is generally relatively low. The reason is that the nanofibrous membrane is formed by stacking layers of nanofibers, there is no fusion between layers, and there is not enough interpenetration and adhesion between fibers. Therefore, although this type of low-strength nanofibrous film shows some good properties, it is limited in practical application. In addition, the preparation capacity of electrospinning equipment with a single-needle nozzle is very low, and basically does not have the potential to develop into large-scale preparation. Therefore, the development of an efficient and multi-nozzle electrospinning device is the key to improving the preparation capacity of the electrospinning method; at the same time, only by greatly improving the mechanical strength of the nanofibrous membrane can we break through the limitations of electrospinning applications. Related patents such as:

US2002175449 (Apparatus and methods for electrospinning polymeric fibers and membranes), KR2003007633 (Fabrication of super-fine polymeric fibrouspolymer separator films for lithium secondary batteries).

Contents of the invention

One of the purposes of the present invention is to provide an electrospinning machine with special mesh electrodes in order to overcome the disadvantage that the above-mentioned common electrospinning equipment is not easy to prepare high-strength nanofiber membranes, and the electrospinning machine is controlled by the special mesh arrangement of the electrodes. The direction in which the nanofibers are ejected during the spinning process makes the fiber strands fully intersect, thereby "weaving" a high-strength nanofiber film.

The second object of the present invention is to provide an application method of the electrospinning machine provided by the first object.

The electrospinning machine and application method provided by the present invention with a special mesh electrode can directly spray the spraying liquid on the surface of the receiving roller of the electrospinning machine to form a high-strength polymer nanofiber diaphragm, which can solve the problem of high-porosity nanofiber membranes under normal conditions. The problem of low mechanical strength of fiber film.

The electrospinning machine with special textured electrodes of the present invention includes: a high-voltage direct current power supply, a high-efficiency multi-needle nozzle, a metering infusion pump, an engineering plastic smooth receiving roller embedded with a special textured copper electrode, a temperature control device, a mechanical control device, and the like.

An electrospinning machine with a temperature control device and a mechanical control device. The multi-needle nozzle of the electrospinning machine is connected to the high-voltage output of one end of the high-voltage DC power supply through a high-voltage wire, and the feed hole of the multi-needle spinneret is connected to the The metering infusion pump is connected; there is an engineering plastic receiving roller with a motor in front of the multi-needle nozzle, and a special textured copper electrode (or other machinable metal material) is embedded on the surface of the receiving roller; the multi-needle nozzle and the receiving roller The horizontal rotation axis of the roller is at the same height; the extended copper wire of the anilox copper electrode on the surface of the receiving roller is connected to the special ground wire through a wire and effectively grounded.

The surface of the receiving roller is embedded with a special textured copper electrode; the surface of the receiving roller is smooth after filling and grinding the gaps generated after the copper electrode is embedded on the surface of the receiving roller.

The reticulation pattern of the reticulated copper electrode is arranged in a regular hexagon, and three diagonal lines in the regular hexagon intersect in a star shape; the side length of the regular hexagon is 35-40mm, and the width of each side is 4-5mm .

The multi-needle shower head is installed on the shower head bracket, and a transmission rack is installed under the bracket of the shower head bracket, and the movement of the rack is controlled by a motor.

The mechanical control device drives the motors of the receiving roller and the multi-needle spray head through wire connections respectively, and controls the rotation of the receiving roller and the reciprocating motion of the multi-needle spinneret.

The high voltage output by the high-voltage DC power supply is connected to the multi-needle spinneret, the ground wire is connected to the receiving roller, and the receiving roller is connected to a special ground wire.

The multi-needle spinneret is a single-row multi-needle spinneret (as shown in Figure 2). The distance between two adjacent needles is 30-72mm, the number of needles is 6-10, the diameter of the pinhole is 0.6-0.8mm, and the length of the cylinder is 15-20mm.

The polymer solution used as the spinning raw material is accurately and quantitatively delivered to the high-efficiency multi-needle nozzle by the metering infusion pump; the high-voltage electric field is generated by the high-voltage DC power supply, and the high voltage output by the high-voltage DC power supply is connected to the multi-needle nozzle, and the ground wire is connected to the receiving roller. .

The charged polymer solution overcomes the surface tension at the tip of the multi-needle spinneret under the action of the electric field force, splits into nanofilaments and sprays them to the receiving roller, forming a high-porosity, high-strength network nanofiber film on the surface of the receiving roller. The temperature control device controls the temperature of the spinning area to be constant between 30 and 50°C.

The process parameters of electrospinning include electric field strength, receiving distance, temperature, spinneret moving speed, receiving roll rotating speed, etc. The electrospinning machine of the present invention can control the above-mentioned various parameters. The composition of the polymer solution is adjusted according to specific needs.

Applying the electrospinning machine with special mesh electrode of the present invention, the method for preparing polymer nanofiber membrane comprises the following steps:

(1) Prepare the polymer spraying liquid, and adjust the viscosity of the solution by controlling the concentration. Generally, the viscosity of the polymer solution suitable for electrospinning is between 300 and 700 mPa·S. The polymer spraying liquid is prepared with an organic solvent, the polymer weight content ranges from 5% to 12%, and the measured viscosity of the spraying liquid is between 300-700mPa·S.

(2) Set the operating parameters of the electrospinning machine according to the viscosity value of the polymer spray liquid measured in step (1). The distance between the spinneret and the receiving roll is adjusted to 5-15 cm, and the voltage is 5-20 kV; the moving speed of the spinneret is 30-60 cm/min, and the rotational speed of the receiving roll is 30-240 cm/min, preferably 30-240 cm/min. 120cm/min; solution delivery speed is 6-24mL/h per needle.

(3) Adjust the temperature in the temperature control device to be constant between 30 and 50°C, turn on the high-voltage power supply, the receiving roller drive motor, the metering infusion pump and the multi-needle nozzle control motor, and the polymer spraying liquid in step (1) is delivered to The needle tip of the multi-needle spinneret is polarized, and a nano-jet with a certain orientation is formed under the action of a strong electric field between the multi-needle spinneret and the reticulated copper electrode; the organic solvent is volatilized during the spraying process, and the formed nanofibers are collected On the surface of the receiving roll, a nanofiber film with high strength and high porosity is gradually formed.

The polymers include polyvinylpyrrolidone (PVP), polyethylene glycol (PEG), polyvinyl alcohol (PVA), polyacrylonitrile (PAN), polyvinylidene fluoride (PVDF), nylon-6 or various conductive polymer.

The organic solvent includes ethanol, isopropanol, m-cresol, dimethylformamide, dimethylacetamide, acetone, dichloromethane, etc. or their mixtures.

In the electrospinning machine with a special mesh electrode, the mesh of the copper mesh embedded on the surface of the receiving roller is arranged in a regular hexagon (three diagonal lines in a regular hexagon intersect in a star shape), and the multi-needle spinneret The orientation of the electric field between the needle tip and the copper mesh is consistent with the mesh pattern. Under the action of this special electric field, the nano-jet flows intersect and weave to form a nanofiber film with high mechanical strength. The tensile strength varies with the material and the electrospinning process conditions, and is about 100-500kg/cm between ² . Compared with the tensile strength (ten to tens of kg/cm ² ) of the nanofiber membrane prepared by common electrospinning equipment, it is nearly an order of magnitude higher. The thickness of the nanofiber film is controllable and proportional to the spraying time; the porosity is 40-70%.

The present invention changes the common metal plate or metal drum electrode design concept in ordinary electrospinning devices, and designs a small electrospinning machine with special mesh copper electrodes and high-efficiency multi-needle nozzles, and prepares nanofibers that can control the orientation of nanofibers. High-strength nanofiber film.

Description of drawings

Figure 1. Schematic diagram of the electrospinning machine of the present invention with special textured electrodes.

Figure 2. Schematic diagram of the high-efficiency multi-needle nozzle of the electrospinning machine with special mesh electrodes of the present invention.

Figure 3. Schematic diagram of the anilox copper electrode embedded in the surface of the receiving roll of the electrospinning machine with the special anilox electrode of the present invention.

Fig. 4. SEM photos of the surface appearance of the polyvinylpyrrolidone nanofiber film of Example 2 of the present invention.

reference sign

1. High-voltage DC power supply 2. Multi-needle nozzle 3. Nozzle bracket

4. Drive rack 5. Motor 6. Metering infusion pump

7. Engineering plastic receiving roller 8. Textured copper electrode 9. Copper electrode extension wire

10. Metal bracket 11. Mechanical control device 12. Temperature control box

Detailed ways

Example 1

Please refer to Figures 1-3. An electrospinning machine (as shown in Figure 1 ) with a temperature control device 12 and a mechanical control device 11, the multi-needle nozzle 2 (as shown in Figure 2 ) of the electrospinning machine passes through the high-voltage wire and the high-voltage DC power supply 1. One end outputs a high-pressure connection, and the feed hole of the multi-needle spinneret is connected to the metering infusion pump 6 through a pipeline; there is an engineering plastic receiving roller 7 installed on a metal bracket 10 directly in front of the multi-needle nozzle, and the engineering plastic receives The roller 7 has a motor 5, and the surface of the receiving roller is embedded with a special textured copper electrode 8 (as shown in Figure 3); the multi-needle nozzle is at the same height as the horizontal rotation axis of the receiving roller; the extended copper electrode of the textured copper electrode on the surface of the receiving roller The wire 9 is connected to the dedicated ground wire through the wire and is effectively grounded.

The reticulation pattern of the reticulated copper electrode is arranged in a regular hexagon, and three diagonal lines in the regular hexagon intersect in a star shape; the side length of the regular hexagon is 40mm, and the width of each side is 5mm.

The multi-needle nozzle is installed on the nozzle bracket 3, and a transmission rack 4 is installed under the bracket of the nozzle bracket, and the movement of the rack is controlled by a motor; the number of needles of the multi-needle nozzle is 6, and the distance between two adjacent needles is 32mm, the multi-needle spinneret hole diameter is 0.6mm, and the length is 20mm.

The mechanical control device drives the motors of the receiving roller and the multi-needle spray head through wire connections respectively, and controls the rotation of the receiving roller and the reciprocating motion of the multi-needle spinneret.

The high voltage output by the high-voltage DC power supply is connected to the multi-needle spinneret, the ground wire is connected to the receiving roller, and the receiving roller is connected to a special ground wire.

Example 2

Preparation weight concentration is the polyvinylpyrrolidone (PVP) ethanol solution of 11%, the viscosity of solution is between 300～400mPa S, stirs 3 days at 25 ℃, adopts the electrospinning machine of embodiment 1, single row of multi-needle nozzles Horizontal reciprocating scanning spraying. Set the rotational speed of the receiving roll to be 30cm/min, the distance between the spinneret and the receiving roll to be 8-10cm, the applied electric field strength to be 1-1.2kV/cm (voltage 8-12kV), and the moving speed of the spinneret to be 40-45cm/min, the solution delivery speed is 8mL/h per needle. Turn on the high-voltage power supply, the drive motor of the receiving roller, the metering infusion pump and the drive motor of the multi-needle nozzle, the operating environment temperature is 30°C, the spraying time is 30 minutes, and the spraying volume is controlled to be 36m ² /h. A uniform polyvinylpyrrolidone nanofiber film is obtained on the surface of the receiving roller, and its surface appearance scanning electron microscope photo (SEM, Fig. 4) shows that the nanofibers forming the film are in an obvious star-shaped intersection, which is consistent with the reticulated shape of the reticulated copper electrode. unanimous. The actual measured net film thickness is 25 μm, and the porosity is 65-70%. The tensile strength is 160~180kg/cm ² .

Example 3

The structure of the electrospinning machine with special mesh electrodes is the same as that in Example 1.

Prepare a polyvinyl alcohol ethanol solution with a weight concentration of 8.2%, the solution viscosity is between 600-700mPa·S, stir at 25°C for 3 days, and use a single row of multi-needle nozzles for horizontal reciprocating scanning and spraying. Set the rotational speed of the receiving roller to 60cm/min, the distance between the nozzle and the receiving roller to be 8-10cm, the applied electric field strength to be 1.2-1.5kV/cm (voltage 10-15kV), and the moving speed of the spinneret to be 40-45cm /min, the solution delivery rate is 15mL/h per needle. Turn on the high-voltage power supply, the drive motor of the receiving roller, the metering infusion pump and the driving motor of the multi-needle nozzle, the operating environment temperature is 40°C, the spraying volume is set to 48mL/h, and the spraying time is 15 minutes, and a uniform white polyvinyl alcohol is obtained on the surface of the receiving roller nanofiber film. The actual measured net film thickness is 19 μm, and the porosity is 58%. The tensile strength is 137kg/cm ² .

Example 4

The structure of the electrospinning machine with special mesh electrodes is the same as that in Example 1.

Prepare a polyacrylonitrile (PAN) DMF solution with a weight concentration of 7%. The viscosity of the solution is between 500 and 600mPa·S. Stir at 25°C for 3 days, and use a single row of multi-needle nozzles to scan and spray horizontally. Set the rotational speed of the receiving roller to 60cm/min, the distance between the nozzle and the receiving roller to be 12-14cm, the applied electric field strength to be 1.2-1.5V/cm (voltage 15-21kV), and the moving speed of the spinneret to be 40-45cm /min, the solution delivery rate is 20mL/h per needle. Turn on the high-voltage power supply, the drive motor of the receiving roller, the metering infusion pump and the drive motor of the multi-needle nozzle, the operating environment temperature is 50°C, the spraying volume is controlled at 48mL/h, and the spraying time is 30 minutes. A uniform film of polyacrylonitrile nanofibers was obtained on the surface of the take-up roll. The actual measured net film thickness is 24 μm, and the porosity is 60-65%. The tensile strength is 260-270kg/cm ² .

Example 5

The structure of the electrospinning machine with special mesh electrodes is the same as that in Example 1.

Prepare a polyvinylidene fluoride (PVDF) DMF/acetone solution with a weight concentration of 9%, the viscosity of the solution is between 600-700mPa·S, stir at 25°C for 3 days, and use a single row of multi-needle nozzles to scan and spray horizontally. Set the rotational speed of the receiving roller to 30cm/min, the distance between the nozzle and the receiving roller to be 10-12cm, the applied electric field strength to be 1.2-1.5V/cm (voltage 12-18kV), and the moving speed of the spinneret to be 45cm/min , the solution delivery rate is 10mL/h per needle. Turn on the high-voltage power supply, the drive motor of the receiving roller, the metering infusion pump and the driving motor of the multi-needle nozzle, the operating environment temperature is 40°C, the spraying time is 30 minutes, and the spraying amount is controlled to 48mL/h, and a uniform polyvinylidene fluoride is obtained on the surface of the receiving roller nanofiber film. The actual measured net film thickness is 24 μm, and the porosity is 55-60%. The tensile strength is 480～500kg/cm ² .

Claims (3)

1. electrostatic spinning machine with special reticulate pattern electrode, this electrostatic spinning machine comprises: high-voltage DC power supply, spininess shower nozzle, metering infusion pump, embed the smooth reception roller of engineering plastics, temperature control equipment and the machine control unit of special reticulate pattern copper electrode; It is characterized in that:

One has the electrostatic spinning machine of temperature control equipment and machine control unit, and the spininess shower nozzle of this electrostatic spinning machine is connected with the end output high pressure of high-voltage DC power supply through high-voltage conducting wires, and the charging hole of spininess spinning head is connected with the metering infusion pump through pipeline; Have the engineering plastics that have motor to receive roller in the dead ahead of spininess shower nozzle, the surface of this reception roller embeds has the special reticulate pattern copper electrode; Spininess shower nozzle and height such as reception roller horizontal axis of rotation grade; The extension copper cash that receives roller surface crazing copper electrode is connected with special-purpose ground wire and effective grounding through lead;

The reticulate pattern of described reticulate pattern copper electrode is regular hexagon arranges, three diagonal star junctions in this regular hexagon; The orthohexagonal length of side is 35～40mm, and the width on each bar limit is 4～5mm;

Described spininess shower nozzle is installed on the head cartridge, below the support of head cartridge, driving rack is installed, and moving of tooth bar controlled by motor;

Described machine control unit connects the motor that drives reception roller and spininess shower nozzle through lead respectively, and control receives the rotation of roller and the reciprocating motion of spininess spinning head;

The height of described high-voltage DC power supply output is crimped on the spininess spinning head, and ground wire is connected on and receives on the roller, receives roller and is connected with special-purpose ground wire;

Described spininess spinning head is single spininess spinning head, and adjacent two pin spacings are 30～72mm, and pinhole aperture is 0.6～0.8mm.

2. electrostatic spinning machine according to claim 1 is characterized in that: the pin number of described spininess spinning head is 6～10, and syringe length is 15～20mm.

3. an application rights requires 1 or 2 described electrostatic spinning machines to prepare the method for high polymer nanometer fiber membrane, it is characterized in that this method may further comprise the steps:

(1) with organic solvent prepared polymer spray coating liquor, the polymer weight content range is 5%～12%, measures spray coating liquor viscosity between 300～700mPaS;

The viscosity number of the polymer spray coating liquor that (2) records according to step (1) is set the running parameter of electrostatic spinning machine; Distance adjustment to 5～15cm between spininess spinning head and the reception roller, voltage-regulation scope 5～20kV; The spinning head rate travel is 30～60cm/min, and receiving roller rotational line speed is 30～240cm/min, and the spray coating liquor transporting velocity is every pin 6～24mL/h;

(3) regulate the interior temperature constant of temperature control equipment between 30～50 ℃; Open high voltage source, receive the roller CD-ROM drive motor, measure infusion pump and spininess shower nozzle control motor; The polymer spray coating liquor of step (1) is transported to the polarization of spininess spinning head needle point place, under the effect of highfield between spininess spinning head and the reticulate pattern copper electrode, is formed with the nanometer jet of certain orientation; Organic solvent volatilizees in course of injection, and the nanofiber of formation is collected in and receives on the roller surface, forms nano-fiber film gradually.

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