Electrospinning method for preparing superfine, non-adhesion polyether ketone ketone nanofiber membrane

Abstract

The application discloses a kind of electrospinning preparation methods of superfine, no adhesion polyether ketone ketone nanofiber membrane: polyether ketone ketone is dissolved in solvent to obtain polyether ketone ketone spinning solution;Polyether ketone ketone spinning solution is loaded in the injector of electrospinning device, and spinning is carried out;The concentration of ethanol or water in spinning environment is improved using solvent atomization between injector needle and collecting device, and polyether ketone ketone jet phase separation is accelerated;The nascent polyether ketone ketone nanofiber is collected into membrane;The fiber membrane collected is soaked in coagulation liquid to make solvent remaining in fiber precipitate, after taking out, dry, obtain polyether ketone ketone nanofiber membrane.The application realizes low concentration electrospinning using the unique interchain topological entanglement of polyether ketone ketone, and promotes phase separation by introducing solvent atomization between spinneret and collecting device, overcome the problem that other polymers are difficult to obtain continuous fiber and fiber is easy to adhere in low concentration electrospinning, and prepare superfine, no adhesion polyether ketone ketone nanofiber membrane.

Description

TECHNICAL FIELD

[0001] The application relates to a method for preparing superfine, non-adhesion polyether ketone ketone nanofiber membranes through low-concentration electrospinning, and belongs to the technical field of nanofibers. BACKGROUND

[0002] In recent years, fiber diameter refinement has become one of the main trends in the development of fiber materials. Fiber refinement brings rich size and surface effects, and has great application prospects in the fields of high-tech such as environment, energy, protection, medical treatment and health. Polyaryletherketone is a kind of semi-crystalline polymer with phenylene ring connected by ether bond and ketone bond, and has the advantages of low density, high strength, high temperature thermal stability, electrical insulation and the like, and is an ideal choice for developing high-end special fibers. How to develop it into micro-nano fiber, especially to refine the fiber diameter to below 100 nm, still faces many challenges.

[0003] There are some related technologies for preparing polyaryletherketone micro-nano fibers at present, but the fiber diameter distribution is uneven and it is difficult to reach below 100 nm. First, due to the strong solvent resistance of polyaryletherketone, concentrated sulfuric acid is generally used to make it sulfonated before electrospinning, but sulfonation changes the molecular chain structure of polyaryletherketone, which significantly reduces the fiber's resistance to solvents, heat and mechanical properties, and it is still difficult to control the uniform distribution of fiber diameter (Literature 1: X. F. Li, X. F. Hao, H. Na. Preparation of nanosilver particles into sulfonated poly(ether etherketone)(S-PEEK) nanostructures by electrospinning. Mater. Lett., 2007, 67(2), 421; Literature 2: Deng D. P., Li Y. L., Jia Y. C., Wang R. H., Zhang Q. X., Liu Y. Electrospinning preparation of polyether ketone ketone ultrafine fibers. Engineering Plastics Application, 2016, 44(4), 44). Some scholars also use dimethylformamide as a solvent for electrospinning of polyaryletherketone, but the obtained fiber diameter is only between 300-600 nm, which is difficult to further refine (Literature 3: Zhang H., Zhang T. J., Bao J. W. Preparation of polyaryletherketone ultrafine fiber nonwoven fabric by high-voltage electrospinning. Journal of Textile Research, 2011, 32(7), 23). In terms of related preparation technologies, Chinese invention patent ZL201910384665.X discloses a preparation method of crystalline polyaryletherketone nanofiber membrane. In view of the solvent resistance of polyaryletherketone, it is modified into soluble polyaryletherketone 1,3 dioxolane or polyaryletherketone imine, and NMP, DMAc or DMF is used as a solvent for electrospinning. Then, through acidification, drying and heat treatment, polyaryletherketone nanofiber with fiber diameter of 110-190 nm is prepared. However, this method is complex, has poor controllability, low production efficiency and small output, and the fiber has poor solvent resistance. Chinese invention patent application 202211043639.9 dissolves polyether ether ketone in a dispersion liquid containing nanoparticles at high temperature and high pressure, and obtains polyether ether ketone nanofiber through flash spinning. Finally, the fiber membrane is prepared through fiber separation, web laying and hot pressing, and the fiber diameter is 10-900 nm. The fiber diameter distribution range obtained by this method is large, and the continuity of the fiber is poor. Chinese invention patent application 202111490448.2 dissolves polyaryletherketone in a solvent at high temperature and a certain pressure (1-50 MPa) to obtain a spinning solution, which is sprayed through the spinneret of the flash spinning equipment. After the solvent is fully evaporated, polyaryletherketone fiber is obtained. The fiber diameter obtained by this patent is very uneven (10-5000 nm), and the dissolution needs to be carried out at high temperature.

[0004] Electrospinning is the main method for preparing ultra-fine polymer fibers at present. The range of polymers that can be used for spinning is very wide, and common polymers include polyethylene oxide, nylon, polyester, polyacetylene, polyethylene oxide, polyvinylidene fluoride, polycarbonate, and polymethyl methacrylate. However, the diameters of the fibers prepared by existing processes are mostly above 200 nm. Some researchers have reduced the fiber diameter to tens of nanometers by reducing the concentration of the spinning solution, but the fibers are discontinuous and have serious beading. For example: (1) Chinese invention patent application 201510894143.6 discloses a technology for electrospinning ultra-fine nanofibers, which uses a nylon-4,6 / formic acid solution as the spinning dope, and adds a small amount of pyridine to increase the solution conductivity. The fiber diameter can be reduced to 1.6 nm when the solution mass concentration is 2%. However, the length of the fibers obtained by this method is not more than 100 nm, and only the fragment fibers can be ultra-fine, and the beading phenomenon on the fibers is very serious. (2) Chinese invention patent ZL201010505164.1 discloses a method for preparing polypropylene ultra-fine fibers at room temperature using electrospinning technology. Glutaraldehyde is used as a crosslinking agent to crosslink polyacrylamide to increase the molecular weight. By adjusting the process parameters (such as the amount of crosslinking agent, the concentration of the spinning solution, the spinning voltage, the receiving distance, etc.), crosslinked polyacrylamide ultra-fine fibers with a fiber diameter of 200-950 nm are finally obtained. The fiber diameter distribution obtained by this patent is uneven, and the proportion of ultra-fine fibers is low. (3) Chinese invention patent application 202110744242.1 mixes nylon 6 and modified silicon dioxide, melts to obtain a mixture, and slices it. Then cellulose acetate butyrate is added to the molten mixture after slicing, and they are put into a screw extruder together. After melt granulation, the mixture is pushed by the screw and stretched through the electrospinning mechanism to obtain a compounded fiber bundle. Finally, the compounded fiber bundle is passed through a solution of acetone and recycled several times to obtain nanofibers with a body diameter of less than 1 μm. The fiber membrane obtained by this patent is net-like, and the body fiber diameter is relatively large, not reaching the true nanometer level. (4) Chinese invention patent application 201210120027.5 adds polyethylene with a mass content of 0.1-5% and an antioxidant with a mass content of 0.005-2% to the corresponding solvent, and prepares a polyethylene spinning solution under high temperature conditions. Then electrospinning is performed, and the obtained fibers are placed in an extracting agent for 1-5 days to allow the solvent in the fibers to be removed, obtaining ultra-high molecular weight polyethylene ultra-fine fibers with a diameter of 80 nm-2 μm. The removal of the solvent by this patent takes a long time, and the process is complex. (5) Chinese invention patent ZL202110246362.9 dissolves polyvinylidene fluoride and tetrabutylammonium chloride in DMF and acetone, heats to 70°C, stirs for 3-4 h, then stirs for 18-20 h without heating to obtain a spinning solution. Electrospinning is performed to obtain a fiber membrane composed of fibers with a diameter of less than 100 nm. However, the fiber membrane obtained by this patent is a fully adhered net-like structure, and continuous single fibers cannot be prepared.Therefore, how to realize the controllable preparation of superfine and non-adhesion nanofiber is still a problem to be solved at present.

[0005] Generally speaking, the lower the concentration of the polymer solution in the electrospinning process, the smaller the diameter of the obtained nanofiber. However, after the concentration is reduced, the spinnability of the polymer solution is generally reduced, it is difficult to realize stable spinning, and the obtained fiber is seriously adhered, and cannot form a continuous fiber structure.

[0006] Polyether ketone ketone is one of the important members of polyaryletherketone polymers. Compared with other polyaryletherketone polymers such as polyether ether ketone, polyether ketone ketone contains more ketone bonds, and the molecular structure has a difference in the ratio of para-benzene and meta-benzene (T / I), so it has a rich spatial topological structure, which greatly promotes the mutual entanglement between chains. Recently, Chinese invention patents ZL202111055042.1 and ZL202111401064.9 and Chinese invention patent applications 202210401927.0 and 202310087414.1 disclose the use of fluorine-based or chlorine-based polar solvents to dissolve polyether ketone ketone and develop high-performance fibers, composites, composite powders and insulating films and related technologies, which can be further used to develop superfine polyether ketone ketone fiber preparation technology. Therefore, based on the high solubility and interchain topological entanglement of polyether ketone ketone, it is expected to develop continuous nanofiber electrospinning at low concentration, and develop high-performance polyether ketone ketone nanofiber materials. SUMMARY

[0007] The technical problem to be solved by the present application is to provide a low-concentration electrospinning preparation method of superfine and non-adhesion polyether ketone ketone nanofiber.

[0008] In order to solve the above problems, the present application provides a low-concentration electrospinning preparation method of superfine and non-adhesion polyether ketone ketone nanofiber film, comprising the following steps:

[0009] Step 1): Dissolve polyether ketone ketone in a solvent at room temperature to obtain a uniform polyether ketone ketone spinning solution;

[0010] Step 2): Put the obtained polyether ketone ketone spinning solution into the syringe of the electrospinning device, connect the syringe needle to the positive electrode of the power supply, and connect the collecting drum to the negative electrode of the power supply, and then spin;

[0011] Step 3): Use solvent atomization between the syringe needle and the collecting device to increase the concentration of ethanol or water in the spinning environment, and accelerate the phase separation of polyether ketone ketone jet;

[0012] Step 4): Collect the primary spun polyether ketone ketone nanofiber into a film;

[0013] Step 5): The collected fiber membrane is soaked in a coagulation liquid to remove the residual solvent in the fiber, and then taken out and dried in an oven to obtain a poly (ether ketone ketone) nanofiber membrane.

[0014] Preferably, the poly (ether ketone ketone) in step 1) has a molar ratio of para-phenyl structure to ortho-phenyl structure of 50:50-100:0; the poly (ether ketone ketone) is selected from a powder with a particle size of ≤300 μm; the solvent is any one of fluorine-based or chlorine-based polar solvents, or a mixed solvent of any one of fluorine-based or chlorine-based polar solvents and dichloroethane; the process conditions for dissolving are as follows: stirring at a speed of 1200-1800 rpm at room temperature for 6-24 h; the mass concentration of the obtained poly (ether ketone ketone) spinning solution is 2-5%, preferably 2-3%.

[0015] More preferably, the fluorine-based or chlorine-based polar solvent is specifically trifluoroacetic acid, 3,3,3-trifluoro-2,2-dimethylpropionic acid, p-chlorophenol, dichloroacetic acid or dichloropropionic acid.

[0016] Preferably, the distance between the syringe needle and the collection device in step 2) is 8-15 cm, the voltage applied by the power source is 30-35 kV, and the advancing speed of the syringe is 0.2-1.0 mL / h.

[0017] Preferably, the solvent in step 3) is anhydrous ethanol, deionized water or a mixed solution of the two.

[0018] Preferably, the collection device of the membrane in step 4) is a flat plate or a roller; wherein the rotating speed of the roller for collection is 300-600 rpm.

[0019] Preferably, the coagulation liquid in step 5) is anhydrous ethanol, deionized water or a mixed liquid of the two, and the soaking time is 2-5 min; the drying temperature is 60-80℃, and the time is 6 h.

[0020] The application also provides a super-fine, non-adhesion poly (ether ketone ketone) nanofiber membrane prepared by the electrospinning method.

[0021] Preferably, the diameter of the fiber in the poly (ether ketone ketone) nanofiber membrane is 30-110 nm, wherein the proportion of fibers with a diameter of less than 60 nm is more than 80%, and the tensile strength of the fiber membrane reaches 12 MPa.

[0022] The present application is based on the technical breakthrough that polyether ketone ketone can be dissolved in fluorine-based and chlorine-based polar solvents, and nanofibers are prepared by electrospinning of polyether ketone ketone solution. In view of the technical limitation that the diameter of the existing polyaryletherketone electrospun fiber can only be refined to 300-600 nm, the present application innovatively develops an electrospinning preparation technology of superfine and non-adhesion polyether ketone ketone nanofiber at low concentration (<3 wt%) by using the unique high solubility and interchain topological entanglement ability of polyether ketone ketone. The concentration of ethanol or water in the spinning environment is increased by using solvent atomization between the syringe needle and the collection device, the polyether ketone ketone jet phase separation is accelerated, and polyether ketone ketone nanofiber with a diameter of 30-110 nm is obtained, in which the fiber with a diameter of less than 60 nm accounts for more than 80%. The present application overcomes the problems that continuous fibers are difficult to obtain and fibers are prone to adhesion in low-concentration electrospinning of other polymers, and a superfine and non-adhesion polyether ketone ketone nanofiber membrane is prepared. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 The schematic diagram of the preparation device used in the present application is shown in the figure;

[0024] Figure 2 The scanning electron microscope image of the polyether ketone ketone nanofiber membrane prepared in Example 1 is shown in the figure;

[0025] Figure 3 The scanning electron microscope image of the polyether ketone ketone nanofiber membrane prepared in Example 2 is shown in the figure;

[0026] Figure 4 The scanning electron microscope image of the polyether ketone ketone nanofiber membrane prepared in Example 3 is shown in the figure;

[0027] Figure 5 The scanning electron microscope image of the polyether ketone ketone superfine fiber membrane prepared in Comparative Example 1 is shown in the figure;

[0028] Figure 6 The scanning electron microscope image of the polyether ketone ketone superfine fiber membrane prepared in Comparative Example 2 is shown in the figure;

[0029] Figure 7 The diameter distribution graph of the polyether ketone ketone nanofiber membrane prepared in Example 2 is shown in the figure;

[0030] Figure 8 The tensile curve of the polyether ketone ketone nanofiber membrane prepared in Example 2 is shown in the figure;

[0031] Figure 9 The differential scanning calorimetry test curve of the polyether ketone ketone nanofiber membrane prepared in Example 2 in a nitrogen environment is shown in the figure;

[0032] Figure 10 The thermogravimetric test curve of the polyether ketone ketone nanofiber membrane prepared in Example 2 in a nitrogen environment is shown in the figure. DETAILED DESCRIPTION

[0033] In order to make the present application more apparent, the preferred embodiments are described in detail below with reference to the accompanying drawings.

[0034] The device used in each embodiment, as shown in Figure 1 includes a syringe 1, a power supply 2, a collection roller 4, and an ethanol atomizing device 3 for spraying liquid between the syringe 1 and the collection roller 4 (the arrows in the figure indicate the spraying direction).

[0035] Example 1

[0036] The present embodiment provides a method for preparing ultrafine, non-adhesive polyether ketone ketone nanofiber membranes by low-concentration electrospinning, which comprises the following steps:

[0037] Step 1: Dissolve 5 g of polyether ketone ketone powder (the molar ratio of para-phenyl structure to ortho-phenyl structure is denoted as T / I ratio of 70:30) in 95 g of trifluoroacetic acid solution, and stir at room temperature using a magnetic stirrer (speed 1500 rpm) for 8 h to obtain a polyether ketone ketone spinning solution with a concentration of 5 wt%.

[0038] Step 2: After the electrospinning device is assembled, set the following technical parameters: spinning speed 0.4 ml / h, spinning voltage 30 kV, needle distance from the receiving device 12.5 cm, roller speed 350 rpm, spinning humidity 35%, spinning temperature 25°C, and ethanol content in the spinning area 35%, and start spinning for 30 min.

[0039] Step 3: Place the polyether ketone ketone fiber membrane prepared above in a 75% ethanol solution and coagulate for 3 min to completely precipitate the solvent in the polyether ketone ketone fiber membrane. The coagulated polyether ketone ketone film is dried in an oven at 60°C for 6 h to obtain a polyether ketone ketone ultrafine fiber membrane with an average diameter of 80 nm.

[0040] Example 2

[0041] The present embodiment provides a method for preparing ultrafine, non-adhesive polyether ketone ketone nanofiber membranes by low-concentration electrospinning, which comprises the following steps:

[0042] Step 1: Dissolve 5 g of polyether ketone ketone powder (the molar ratio of para-phenyl structure to ortho-phenyl structure is denoted as T / I ratio of 70:30) in 95 g of trifluoroacetic acid solution, and stir at room temperature using a magnetic stirrer (speed 1500 rpm) for 8 h to obtain a polyether ketone ketone spinning solution with a concentration of 5 wt%.

[0043] Step 2: After the electrospinning device was assembled, the following technical parameters were set: the spinning speed was 0.6 ml / h, the spinning voltage was 32 kV, the distance between the needle and the receiving device was 15 cm, the drum rotation speed was 350 rpm, the spinning humidity was 40%, the spinning temperature was 25°C, and the ethanol content in the spinning area was 40%, and the spinning was started for 30 min.

[0044] Step 3: The same as step 3 in Example 1, a polyether ketone ketone ultrafine fiber membrane with an average diameter of 60 nm was obtained.

[0045] The polyether ketone ketone nanofiber membrane prepared above was subjected to performance testing after being solidified by anhydrous ethanol, precipitating the solvent and drying at 60°C for 3 h. Among them, the fiber membrane was cut into a 1 x 3 cm strip for tensile testing, and the tensile speed was 0.1 mm / min, and the results are shown in Figure 8 The film was subjected to DSC and TG testing, and the results are shown in Figure 9 、 Figure 10 From the test results, it can be seen that the prepared polyether ketone ketone nanofiber membrane has good mechanical properties and thermal properties, and at the same time, the continuous non-adhesion polyether ketone ketone nanofiber membrane is prepared through the above steps.

[0046] Example 3

[0047] The present embodiment provides a method for preparing ultrafine and non-adhesion polyether ketone ketone nanofiber membrane by low concentration electrospinning, comprising the following steps:

[0048] Step 1: 2 g of polyether ketone ketone powder (the molar ratio of para-phenyl structure and ortho-phenyl structure is denoted as T / I ratio of 60:40) was dissolved in 98 g of trifluoroacetic acid-dichloroethane mixed solution, and the mass ratio of trifluoroacetic acid and dichloroethane in the mixed solution was 7:3. The solution was stirred at room temperature using a magnetic stirrer (rotation speed 1500 rpm) for 8 h to obtain a polyether ketone ketone spinning solution with a concentration of 2 wt%.

[0049] Step 2: After the electrospinning device was assembled, the following technical parameters were set: the spinning speed was 0.9 ml / h, the spinning voltage was 35 kV, the distance between the needle and the receiving device was 13 cm, the drum rotation speed was 500 rpm, the spinning humidity was 40%, the spinning temperature was 25°C, and the ethanol content in the spinning area was 50%, and the spinning was started for 30 min.

[0050] Step 3: The same as step 3 in Example 1, a polyether ketone ketone ultrafine fiber membrane with an average fiber diameter of 50 nm was obtained.

[0051] Comparative Example 1

[0052] Step 1: 7 g of polyether ketone ketone powder (molar ratio of para-phenyl structure and ortho-phenyl structure, denoted as T / I ratio of 70:30) was dissolved in 93 g of trifluoroacetic acid solution, and stirred at room temperature using a magnetic stirrer (speed of 1500 rpm) for 8 h to obtain a polyether ketone ketone spinning solution with a concentration of 7 wt%.

[0053] Step 2: After the electrospinning device was assembled, the following technical parameters were set: spinning speed of 0.2 ml / h, spinning voltage of 25 kV, needle distance from the receiving device of 15 cm, drum speed of 400 rpm, spinning humidity of 35%, spinning temperature of 25°C, and ethanol content in the spinning area of 35%, and spinning was started for 30 min.

[0054] Step 3: The polyether ketone ketone fiber membrane prepared above was placed in a 75% ethanol solution and coagulated for 3 min to completely precipitate the solvent in the polyether ketone ketone fiber membrane. The coagulated polyether ketone ketone film was dried in an oven at 60°C for 6 h to obtain a polyether ketone ketone nanofiber membrane with an average diameter of 500 nm.

[0055] Comparative Example 2

[0056] Step 1: 3 g of polyether ketone ketone powder (molar ratio of para-phenyl structure and ortho-phenyl structure, denoted as T / I ratio of 60:40) was dissolved in 97 g of trifluoroacetic acid solution, and stirred at room temperature using a magnetic stirrer (speed of 1500 rpm) for 8 h to obtain a polyether ketone ketone spinning solution with a concentration of 3 wt%.

[0057] Step 2: After the electrospinning device was assembled, the following technical parameters were set: spinning speed of 0.6 ml / h, spinning voltage of 32 kV, needle distance from the receiving device of 15 cm, drum speed of 350 rpm, spinning humidity of 40%, and spinning temperature of 25°C, and spinning was started for 30 min.

[0058] Step 3: The same as Step 3 in Example 1, a polyether ketone ketone fiber membrane with more string beads and serious adhesion was obtained.

Claims

1. A method for preparing ultrafine, non-adhesive polyether ketone ketone nanofiber membranes by electrospinning, characterized in that, Includes the following steps: Step 1): At room temperature, polyetherketoneketone is dissolved in a solvent to obtain a uniform polyetherketoneketone spinning solution; in the polyetherketoneketone, the molar ratio of p-phenyl structure to ortho-phenyl structure is 50:50 to 100:0; the solvent is any one of fluorine-based or chlorine-based polar solvents, or any one of fluorine-based or chlorine-based polar solvents mixed with dichloroethane. Step 2): The obtained polyether ketone ketone spinning solution is loaded into the syringe of the electrospinning device. The syringe needle is connected to the positive terminal of the power supply, and the collecting roller is connected to the negative terminal of the power supply for spinning. Step 3): The concentration of ethanol or water in the spinning environment is increased by solvent atomization between the syringe needle and the collecting device to accelerate the separation of the polyether ketone jet phase; the solvent is anhydrous ethanol, deionized water or a mixture of both. Step 4): Collect the initially spun polyether ketone nanofibers into a membrane; Step 5): Immerse the collected fiber membrane in a coagulation solution to allow the residual solvent in the fiber to precipitate out. After removal, dry it in an oven to finally obtain a polyether ketone nanofiber membrane.

2. The method for preparing ultrafine, non-adhesive polyether ketone ketone nanofiber membranes by electrospinning as described in claim 1, characterized in that, The polyether ketone ketone used in step 1) is a powder with a particle size ≤300μm; the dissolution process conditions are: stirring at 1200-1800rpm for 6-24h at room temperature; the mass concentration of the resulting polyether ketone ketone spinning solution is 2-5%.

3. The method for preparing ultrafine, non-adhesive polyether ketone ketone nanofiber membranes by electrospinning as described in claim 2, characterized in that, The fluorinated or chlorinated polar solvents are specifically trifluoroacetic acid, 3,3,3-trifluoro-2,2-dimethylpropionic acid, p-chlorophenol, dichloroacetic acid, or dichloropropionic acid.

4. The method for preparing ultrafine, non-adhesive polyether ketone ketone nanofiber membranes by electrospinning as described in claim 1, characterized in that, In step 2), the distance between the syringe needle and the collecting device is 8-15 cm, the voltage applied by the power supply is 30-35 kV, and the syringe advance speed is 0.2-1.0 mL / h.

5. The method for preparing ultrafine, non-adhesive polyether ketone ketone nanofiber membranes by electrospinning as described in claim 1, characterized in that, In step 4), the membrane collection device is a flat plate or a drum; wherein the drum collection speed is 300-600 rpm.

6. The method for preparing ultrafine, non-adhesive polyether ketone ketone nanofiber membranes by electrospinning as described in claim 1, characterized in that, The coagulation solution in step 5) is anhydrous ethanol, deionized water, or a mixture of the two, and the soaking time is 2 to 5 minutes; the drying temperature is 60 to 80°C, and the time is 6 hours.

7. The ultrafine, non-adhesive polyether ketone ketone nanofiber membrane prepared by the electrospinning method according to any one of claims 1-6.

8. The ultrafine, non-adhesive polyether ketone ketone nanofiber membrane as described in claim 7, characterized in that, The diameter of the polyether ketone nanofiber membrane is 30-110 nm, of which fibers with a diameter of less than 60 nm account for more than 80%.

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