Hot-air-flow-assisted electrospinning method for improving yield of nanofibers

Abstract

The invention provides a hot airflow-assisted electrospinning method for improving the yield of nanofibers, which comprises the following steps: dissolving a high-molecular polymer in a solvent to prepare a spinning solution; and carrying out electrostatic spinning on the spinning solution to a collection substrate by utilizing a hot air flow auxiliary electrospinning device to obtain the nanofiber. According to the method, the volatilization speed of solvents (including water systems and non-water systems) in the spinning process is remarkably increased, the problem that spinning is difficult to conduct through a spinning solution with the low solvent volatilization speed is solved, and the water-based spinning solution with the high-molecular polymer concentration as low as 1 wt% can be electrospun; spinning jet flow is further stretched and split through hot air flow, fibers with smaller diameters are formed and deposited on a collecting substrate, the yield is increased, meanwhile, the specific surface area of the nanofibers is increased, functional substances are saved, the functional effect of the nanofibers is improved, and the yield of the prepared nanofibers can reach 10 g / h; and the problem that the needle head is blocked when a solvent near the needle head is promoted to volatilize by heating is avoided.

Description

Technical Field

[0001] The invention belongs to the field of textile technology, and in particular relates to a hot air flow assisted electrospinning method for improving the yield of nanofibers. Background Art

[0002] As an advanced material, nanofibers have shown broad application prospects in energy production, water treatment, environmental remediation, biomedicine, flexible electronics, aerospace, etc. due to their excellent mechanical properties, extremely high specific surface area, high porosity and other characteristics. A variety of nanofiber preparation technologies have been reported, but some methods are only suitable for laboratory-scale research and are difficult to apply on a large scale in industrial production, such as template synthesis, molecular self-assembly and hydrothermal method. Although melt-blown spinning technology has been industrialized, the fiber diameter prepared by this method is generally coarse, and this method can only produce thermoplastic polymers.

[0003] Electrospinning is used as a universal method for preparing nanofibers in various fields due to its excellent versatility, simplicity and low cost of processing system. However, this technology also has some problems: 1) The production process requires the addition of high-voltage static electricity of more than ten to several tens of kilovolts; 2) There is a problem of low production efficiency; 3) The spinning effect on water-based spinning solution is not good because the solvent (water) evaporates too slowly, resulting in adhesion and droplet residue problems; 4) Generally, organic solvents with faster evaporation rates are selected, such as acetone, N,N-dimethylformamide, dichloromethane, dimethylacetamide, tetrahydrofuran, etc., but these organic solvents usually cause serious harm to the environment and human body, and there are also safety hazards such as flammability and explosion.

[0004] Hot air flow assisted electrospinning can accelerate solvent volatilization, but existing hot air flow auxiliary components generally form a coaxial structure with the spinning head, with the inner layer being the spinning solution and the outer layer being the auxiliary hot air flow. This design easily causes blockage of the inner spinning head. Summary of the invention

[0005]

Technical issues

[0006] Electrospinning technology has a poor effect on spinning water-based spinning solutions. It is difficult to spin uniform, small-diameter nanofibers from water-based spinning solutions, and the production efficiency is low and the required voltage is high. Hot air flow-assisted electrospinning can accelerate solvent evaporation, but the existing hot air flow auxiliary components generally form a coaxial structure with the spinning head, which easily causes the inner spinning head to be blocked, which is not conducive to improving production efficiency.

[0007]

Technical solution

[0008] In order to solve the above problems, the present invention provides a hot air flow assisted electrospinning device, wherein the hot air flow auxiliary device is located on the side of the spinning nozzle. During the electrospinning process, the auxiliary air flow is blown onto the spinning jet, thereby avoiding needle blockage, accelerating the volatilization of the solvent, and solving the problem that the polymer solution with a low solvent volatilization rate is difficult to spin; the spinning jet is stretched and split by the hot air flow to form nanofibers with finer diameters that are deposited on the collecting substrate.

[0009] The first object of the present invention is to provide a hot air flow assisted electrospinning method for improving the yield of nanofibers, comprising the steps of:

[0010] (1) dissolving a high molecular weight polymer in a solvent to obtain a spinning solution;

[0011] (2) Using a hot air flow-assisted electrospinning device, the spinning solution is electrospun onto a collecting substrate to obtain nanofibers.

[0012] In one embodiment of the present invention, in step (1), the high molecular polymer is one or more of carboxymethyl chitosan, polyethylene oxide, dimethylformamide, polyvinyl alcohol, sodium alginate, hyaluronic acid, polycaprolactone, polyacrylic acid, polyvinyl pyrrolidone, polylactic acid, sodium alginate, silk protein, polyacrylonitrile, cellulose acetate, polyvinyl acetate alcohol, polyvinyl butyral, polyvinylidene fluoride, and polystyrene.

[0013] In one embodiment of the present invention, in step (1), the solvent is one or more of water, N,N-dimethylformamide, dimethylacetamide, dichloromethane, tetrahydrofuran, acetone, methanol, and ethanol.

[0014] In one embodiment of the present invention, in step (1), the concentration of the high molecular weight polymer in the spinning solution is 1 to 25 wt %.

[0015] In one embodiment of the present invention, in step (2), the hot air flow assisted electrospinning device includes components: a hot air flow assisted device, a spinning nozzle, a high voltage power supply, and a collecting substrate; the hot air flow assisted device is located on the side of the spinning nozzle.

[0016] In one embodiment of the present invention, in step (2), the distance between the hot air flow auxiliary device and the spinning nozzle is 45 to 60 cm. When the hot air flow temperature is high, the distance between the hot air flow auxiliary device and the spinning nozzle needs to be larger.

[0017] In one embodiment of the present invention, the collecting substrate is a fabric, a yarn or a metal receiver.

[0018] In one embodiment of the present invention, in step (2), the voltage of electrospinning is 2 to 50 kV.

[0019] In one embodiment of the present invention, in step (2), the electrospinning solution propulsion speed is 0.8 to 50 mL / h.

[0020] In one embodiment of the present invention, in step (2), the spinning distance of electrospinning is 15 to 70 cm.

[0021] In one embodiment of the present invention, in step (2), the width of the collected substrate is 200 to 2000 mm.

[0022] In one embodiment of the present invention, in step (2), the auxiliary hot air flow pressure of electrospinning is 0.1-0.7 MPa.

[0023] In one embodiment of the present invention, in step (2), the temperature of the auxiliary hot air flow for electrospinning is 100 to 580°C.

[0024] In one embodiment of the present invention, in step (1), a high molecular polymer and a functional substance are dissolved in a solvent to prepare a spinning solution.

[0025] In one embodiment of the present invention, in step (1), the concentration of the functional substance in the spinning solution is 0.1 to 10 wt %.

[0026] In one embodiment of the present invention, the functional substance is one of an antibacterial substance, a warming substance, and a cooling substance.

[0027] In one embodiment of the present invention, the functional substance is an antibacterial substance, and the antibacterial substance is one or more of phenol antibacterial agents, silicone quaternary ammonium salt antibacterial agents, guanidine antibacterial agents, polysaccharide antibacterial agents, silver ion antibacterial agents, and imidazole antibacterial agents.

[0028] In one embodiment of the present invention, the functional substance is an antibacterial substance, and the antibacterial substance is one or more of triclosan, 3-(trimethoxysilyl)propyldimethyloctadecylammonium chloride, polyhexamethylene biguanide hydrochloride, 3-(trimethoxysilyl)propyldimethyltetradecyl quaternary ammonium salt, chitin, chitosan, and Ag zeolite.

[0029] The second object of the present invention is to provide nanofibers prepared by the above method.

[0030] The third object of the present invention is to provide functional nanofibers prepared by the above method.

[0031] The fourth object of the present invention is to provide antibacterial nanofibers prepared by the above method.

[0032] The fifth object of the present invention is to provide application of the above antibacterial nanofibers in antibacterial textiles.

[0033] In one embodiment of the present invention, the antimicrobial textiles include shirts, coats, socks, underwear, bed sheets, towels, protective clothing, masks, and gloves.

[0034] Beneficial effects:

[0035] The present invention adopts a hot air flow-assisted electrospinning device, which significantly improves the volatilization rate of the solvent (including aqueous and non-aqueous systems) in the spinning process, and solves the problem that the spinning solution with a low solvent volatilization rate is difficult to spin.

[0036] The present invention adopts a hot air flow assisted electrospinning device, which can further stretch and split the spinning jet to form fibers with finer diameters and deposit them on a collecting substrate, thereby improving the yield and increasing the specific surface area of ​​the nanofibers, saving functional substances and improving the functional effects of the nanofibers.

[0037] Compared with the electrospinning device in which the hot air flow is coaxial with the needle, the hot air flow assisted electrospinning device used in the present invention avoids the problem of needle clogging caused by heating to promote the volatilization of the solvent near the needle.

[0038] The invention can electrospin a water-based spinning solution with a high molecular polymer concentration as low as 1wt%. The prepared nanofibers are uniform and smooth without a beaded structure and have a good inhibitory effect on Staphylococcus aureus and Escherichia coli.

[0039] The productivity of the nanofibers prepared by the present invention can be as high as 10 g / hour. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 Schematic diagram of hot air flow assisted electrospinning device;

[0041] In the figure: 1. Spinning jet; 2. Spinning nozzle; 3. Spinning solution; 4. High voltage power supply; 5. Auxiliary air flow; 6. Collecting substrate.

[0042] Figure 2 This is the SEM photograph of the water-soluble CMCS / PEO nanofibers prepared in Example 1.

[0043] Figure 3 The antibacterial effect of the water-soluble CMCS / PEO nanofibers prepared in Example 1 on Staphylococcus aureus (a) and Escherichia coli (b).

[0044] Figure 4 This is the SEM photograph of the water-insoluble triclosan / PCL nanofibers prepared in Example 4. DETAILED DESCRIPTION

[0045] Example 1

[0046] A hot air flow assisted electrospinning method for improving the yield of nanofibers comprises the following steps:

[0047] (1) 3 g of carboxymethyl chitosan (CMCS) (molecular weight of 180,000, 95% N-deacetylation) and 0.2 g of polyethylene oxide (PEO) (molecular weight of 5 million) were dissolved in 40 g of deionized water and magnetically stirred at room temperature for 4 h until the solution became transparent and uniform, thereby preparing an aqueous spinning solution.

[0048] (2) Using a hot air flow assisted electrospinning device, the hot air flow assisted device was 52 cm away from the spinning nozzle, and the aqueous spinning solution was electrospun. The spinning solution propulsion speed was 3.5 mL / h, the spinning distance was 50 cm, the width of the collecting substrate was 500 mm, the voltage was 3 kV, the auxiliary hot air flow pressure was 0.3 MPa, and the auxiliary hot air flow temperature was 300 ° C to obtain CMCS / PEO antibacterial nanofibers.

[0049] For the aqueous spinning solution, the yield of nanofibers prepared by the hot air flow-assisted electrospinning device can be as high as 6 g / hour.

[0050] The morphology of the prepared CMCS / PEO antibacterial nanofibers is shown in Figure 2 As shown in the figure, the CMCS / PEO antibacterial nanofibers are uniform and smooth without beaded structures. Hot air flow can accelerate the volatilization of solvents. Faster solvent volatilization can bring higher spinning rates and also increase the spinnability of solution systems with slower solvent volatilization rates such as water-based polymers.

[0051] CMCS is an electrospinnable polymer with antibacterial properties. Figure 3 As shown, the prepared CMCS / PEO antibacterial nanofibers have good inhibitory effects on Staphylococcus aureus and Escherichia coli.

[0052] Example 2

[0053] A hot air flow assisted electrospinning method for improving the yield of nanofibers comprises the following steps:

[0054] (1) 10 g of polyvinyl alcohol (PVA) (molecular weight 18,000) and 0.1 g of triclosan were dissolved in 90 g of deionized water and magnetically stirred at 60 degrees Celsius for 12 hours until the solution became transparent and uniform, thereby preparing an aqueous spinning solution.

[0055] (2) Using a hot air flow assisted electrospinning device, the hot air flow assisted device was 55 cm away from the spinning nozzle, and the aqueous spinning solution was electrospun. The spinning solution propulsion speed was 3 mL / h, the spinning distance was 50 cm, the width of the collecting substrate was 500 mm, the voltage was 3 kV, the auxiliary hot air flow pressure was 0.3 MPa, and the auxiliary hot air flow temperature was 350°C to obtain PVA antibacterial nanofibers.

[0056] The prepared nanofibers are uniform and smooth without beaded structures.

[0057] Example 3

[0058] A hot air flow assisted electrospinning method for improving the yield of nanofibers comprises the following steps:

[0059] (1) 0.15 g of polyethylene oxide (PEO) (molecular weight 5 million) and 0.6 g of sodium alginate (molecular weight 5000) were dissolved in 20 g of deionized water and magnetically stirred at 40 degrees Celsius for 6 hours until the solution became transparent and uniform, thereby preparing an aqueous spinning solution.

[0060] (2) Using a hot air flow assisted electrospinning device, the hot air flow assisted device is 50 cm away from the spinning nozzle, and the aqueous spinning solution is electrospun. The spinning solution propulsion speed is 3.5 mL / h, the spinning distance is 50 cm, the width of the collecting substrate is 500 mm, the voltage is 2.5 kV, the auxiliary hot air flow pressure is 0.35 MPa, and the auxiliary hot air flow temperature is 250°C to obtain nanofibers.

[0061] The prepared nanofibers are uniform and smooth without beaded structures.

[0062] Example 4

[0063] A hot air flow assisted electrospinning method for improving the yield of nanofibers comprises the following steps:

[0064] (1) 38 g of N,N-dimethylformamide and 56 g of tetrahydrofuran solvent were mixed, and 1 g of antibacterial agent triclosan (triclosan, C 12 H 7 Cl 3 O 2 ), stirred at room temperature for 30 minutes, and then 6 g of polycaprolactone (PCL, molecular weight 120,000) was added, and magnetic stirring was carried out at room temperature for 12 hours until the solution became transparent and uniform, thereby obtaining a non-aqueous spinning solution.

[0065] (2) Using a hot air flow assisted electrospinning device, the hot air flow assisted device is 50 cm away from the spinning nozzle, and the non-aqueous spinning solution is electrospun. The spinning solution propulsion speed is 5 mL / h, the spinning distance is 50 cm, the width of the collecting substrate is 500 mm, the voltage is 4.5 kV, the auxiliary hot air flow pressure is 0.2 MPa, and the auxiliary hot air flow temperature is 250°C to obtain antibacterial nanofibers.

[0066] For non-aqueous spinning solutions, the device can produce nanofibers at a yield of up to 10 g / hour.

[0067] Example 5

[0068] The difference from Example 1 is that in step (1), 0.1 g of triclosan and 1 g of polyethylene oxide PEO are dissolved in 98.9 g of deionized water.

[0069] Comparative Example 1

[0070] The difference from Example 1 is that the temperature of the auxiliary hot air flow is room temperature.

[0071] Large areas of polymer droplets and incompletely solidified fibers were obtained on the substrate, indicating that satisfactory fiber structures could not be obtained using room temperature airflow to assist spinning.

[0072] The embodiments provided above are not intended to limit the scope of the present invention, and the steps described are not intended to limit the execution order thereof. Those skilled in the art may make obvious improvements to the present invention in combination with existing common knowledge, which also fall within the scope of protection defined by the claims of the present invention.

Claims

1. A hot air flow assisted electrospinning method for improving the yield of nanofibers, characterized in that: Includes steps: (1) dissolving a high molecular weight polymer in a solvent to obtain a spinning solution; (2) Using a hot air flow-assisted electrospinning device, the spinning solution is electrospun onto a collecting substrate to obtain nanofibers.

2. The method according to claim 1, characterized in that In step (1), the high molecular polymer is one or more of carboxymethyl chitosan, polyethylene oxide, polyvinyl alcohol, sodium alginate, hyaluronic acid, polycaprolactone, polyacrylic acid, polyvinyl pyrrolidone, polyethylene imine, polyacrylamide, polylactic acid, polyacrylonitrile, cellulose acetate, polyvinyl acetate alcohol, polyvinyl butyral, polyvinylidene fluoride, and polystyrene; the solvent is one or more of water, N,N-dimethylformamide, dimethylacetamide, dichloromethane, tetrahydrofuran, acetone, methanol, and ethanol; and the high molecular polymer concentration of the spinning solution is 1 to 25wt%.

3. The method according to claim 1, characterized in that In step (2), the hot air flow assisted electrospinning device comprises components: a hot air flow assisted device (1), a spinning nozzle (2), a high voltage power supply (4), and a collecting substrate (6); the hot air flow assisted device is located on the side of the spinning nozzle; and the hot air flow assisted device is 45 to 60 cm away from the spinning nozzle.

4. The method according to claim 1, characterized in that In step (2), during electrospinning, the voltage is 2 to 50 kV, the spinning solution propulsion speed is 0.8 to 50 mL / h, the spinning distance is 15 to 70 cm, the width of the collecting substrate is 200 to 2000 mm, the auxiliary hot air flow pressure is 0.1 to 0.7 MPa, and the auxiliary hot air flow temperature is 100 to 580°C.

5. The method according to claim 1, characterized in that In step (1), a high molecular weight polymer and a functional substance are dissolved in a solvent to prepare a spinning solution; the concentration of the functional substance in the spinning solution is 0.1 to 10 wt%.

6. The method according to claim 5, characterized in that The functional substance is an antibacterial substance, and the antibacterial substance is one or more of phenol antibacterial agents, silicone quaternary ammonium salt antibacterial agents, guanidine antibacterial agents, polysaccharide antibacterial agents, silver ion antibacterial agents, and imidazole antibacterial agents.

7. Nanofibers prepared by the method of claim 1.

8. The functional nanofiber prepared by the method of claim 5.

9. The antibacterial nanofiber prepared by the method of claim 6.

10. Use of the antibacterial nanofiber according to claim 9 in antibacterial textiles.

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