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The method of preparing molybdenum disulfide/carbon composite fibers with an Electrospinning machine: Weigh 1.5 g PAN and 1.5 g ATTM, add them to 8.0 g DMF solvent, and stir at constant temperature for 12 hours to obtain a reddish-brown viscous solution. Electrospinning was performed under the conditions of spinning voltage 18-21 kV, receiving distance 9-11cm, needle diameter 0.8mm, and advancing speed 0.50 mL/h to prepare ATTM/PAN composite fiber, and use an optical microscope to make observations. The preferred ATTM/PAN composite fiber is pre-oxidized in a muffle furnace at a rate of 2°C/min to 250°C and kept at a constant temperature for 1 h, and then the pre-oxidized fiber membrane is placed in a tube furnace. The N2 atmosphere was raised to 800°C at a rate of 4°C/min and kept at a constant temperature for 1 h for carbonization treatment to obtain a molybdenum disulfide/carbon composite fiber.
Cr2o3 fiber electrospinning machine preparation method: experimental polyvinylpyrrolidone(PVC, 1.3 million molecular weight), chromium nitrate (Cr(NO3)3.9H2O), dimethylformamide(DMF) and absolute ethanol are all analytically pure. Weigh a certain amount of PVC and chromium nitrate, add them to the mixed solvent of DMF and absolute ethanol, magnetically stir for 6 hours, and then stand still to obtain a uniform spinning solution. Weigh a certain amount of PVC chromium nitrate, add it to the mixed solvent of DMF and absolute ethanol, magnetically stir for 6 hours and then stand still to obtain a uniform spinning solution. Use a needle syringe to suck the spinning solution and fix it in the electrospinning machine. The fixed negative high voltage is 5 kV, the positive high voltage is 17 kV, the injection speed is 0.2 mm/min, and the receiving distance is 20 cm for electrospinning. Put the spinning sample into the muffle furnace, and heat it up to 600 ℃ at 2 ℃/min for 2 hours to obtain the final product Cr2O3 fiber.
Ultrafine alumina-based ceramic fiber electrospinning machine and its fiber preparation: experimental raw material aluminum hypoacetate (BAA) chemical formula is Al(OH)2(OOCCH3)•1/3H3BO3, boric acid is used as a stabilizer; orthosilicic acid Ethyl ester (TEOS) is analytically pure, with SiO2 mass fraction of 28.0%; linear high molecular polymer P, formulated into a 16% mass fraction of ethanol solution as a spinning aid.
Experimental method: Add aluminum hypoacetate and ethyl orthosilicate to a solvent composed of deionized water and alcohol, and stir for 12 h in a water bath at 40°C. After full hydrolysis, a uniform and transparent sol is obtained. The composition of the target alumina-based fiber product is designed to have a mass ratio of m(Al2O3): m(SiO2): m(B2O3)=62:24:14, in order to obtain a stable spinning solution during the spinning process and a fiber product with good appearance In the experiment, 4 kinds of sols with different mass fractions were prepared: the mass fractions of the sols were expressed by the total mass fractions of aluminum hypoacetate and ethyl orthosilicate in the sols, which were 15.0%, 22.5%, 30.0% and 37.5%, respectively. The sol and the spinning aid are mixed and stirred evenly at a mass ratio of 1:3 to make a spinning solution and perform electrostatic spinning. The electrospinning test parameters are as follows: the voltage is 7.0 kV, the distance between the spinneret and the receiving plate is 15 cm, the liquid supply rate is 0.01 mL/min, and the temperature is 25°C. The spun fibers were sintered at 800°C and 1000°C for 1 h to obtain alumina-based ceramic fibers.
PVA-collagen micro-nanofibers---coaxial Electrospinning machine and its fiber preparation method:
1. The required raw materials are: polyvinyl alcohol (PVA-1788, relative molecular mass 85 000 ～124 000, degree of hydrolysis 87% ～89%, Sigma-Aldrich, collagen is obtained from fresh pig skin by pepsin method in the laboratory. It is a sponge-like collagen made by extracting from it, then purifying and freeze-drying for many times.
2. The required instruments are: high-speed refrigerated centrifuge, freeze dryer, scanning electron microscope.
The collagen sponge prepared by freeze-drying in the laboratory was added to 0.5 mol/L acetic acid solution, and dissolved by magnetic stirring at room temperature, and the mass concentrations were 18, 16, 14 g/L and 12 g/L. The collagen acetic acid aqueous solution is used as the shell solution for coaxial electrospinning. A certain amount of PVA-1788 powder was weighed and added into a three-way flask, and an appropriate amount of deionized water was added. Heated in a 85℃ water bath, electric stirring was carried out at the same time, and the solution was fully dissolved for 2h. The 8% PVA solution was prepared, which could be used as the core layer solution for coaxial electrostatic spinning.
Method 1: Fix the spinning flow rate of the core layer PVA solution at 0.5mL/h, and the shell layer collagen solution at 0.6mL/h; the spinning distance is fixed at 15cm, and the spinning voltage is 15, 20, 25kV, respectively. Coaxial electrospinning fibers with different morphologies can be obtained.
Method 2: The spinning flow rate of the fixed core layer PVA solution is 0.5mL/h, the shell layer collagen solution flow rate is 0.6mL/h; the spinning voltage is 20kV, and the spinning distance is 10, 15, and 20 cm, respectively. Coaxial electrospinning fibers with different morphologies can be obtained.
The method of preparing nitrogen-doped TiO2 nanofibers with an electrospinning machine: The preparation of nitrogen-doped TiO2 nanofibers is divided into three steps.
Step 1: Add 1g of tetra butyl titan ate (TBOT) and 2ml of acetic acid (ACOH) to 2ml of ethanol slowly under the stirring of a magnetic stir bar, and fully stir to obtain A sol. Let A sol stand still at room temperature for 1 to 2 hours to fully hydrolyze it. Add 0.4g of polyvinylpyrrolidone (PVP) and 1ml of dimethylformamide (DMF) to 4ml of ethanol under stirring with a magnetic stirrer, and stir well to obtain B sol. Mix A sol and B sol, and mix them with a magnetic stirring bar for 3 hours to obtain C sol and then stand in the air for aging for 2 to 3 hours to obtain TiO2 wet sol.
Step 2: Inhale 2~3ml of TiO2 wet sol into a medical syringe, use an 8mm stainless steel needle as the spinneret, connect the spinneret and the syringe with a PTFE catheter, connect the spinneret to a 60kV DC power supply, and use a micro-syringe pump to deliver the wet TiO2 sol to the spinneret through the catheter. Lay a piece of zinc flake flat 15cm under the spinneret, and place the quartz flake on the zinc flake to receive electrospinning. Adjust the sol delivery rate, the distance between the spinneret and the zinc flake, etc., so that the wet TiO2 sol forms a stable Taylor cone on the spinneret. Under the action of a high-voltage electric field, the wet TiO2 sol forms a jet, which is deposited on the quartz plate receiving electrospinning along with the volatilization of the solvent to obtain electrospun TiO2 nanofibers.
Step 3: The obtained TiO2 nanofibers are calcined in a NH3 atmosphere at 500-600°C for 3 hours to obtain nitrogen-doped TiO2 nanofibers. The obtained TiO2 nanofibers were calcined at 500-600°C in an air atmosphere for 3 hours to obtain undoped pure TiO2 nanofibers as a comparative sample.
Method for preparing bacteriostatic polyimide nanofibers with electrospinning machine: Reagents and instruments Biphenyltetracarboxylic dianhydride (BPDA), dried at 160℃ for 5h before use; 4,4-diaminodiphenyl ether ( ODA), dry storage; N, IV. Dimethylformamide (DMF), analytical grade, dried with anhydrous magnesium sulfate and distilled under reduced pressure; nitric acid (AgNO), analytical grade, attenuated total reflection-Fourier transform infrared spectrometer, X-ray diffraction (XRD) instrument, contact Angle tester; field emission scanning electron microscope (SEM); high-resolution transmission electron microscope (TEM). Preparation of nanofibers. 0.606g (1.50 mmo1) ODA was dissolved in 10 mL DMF. After the ODA was completely dissolved, 0.8904g (1.51 mmo1) BPDA was added in batches. After the complete dissolution, a uniform light yellow transparent liquid was obtained. ; Then add 0.0784g (0.23mmo1) AgNO and react continuously for 4h under the protection of N gas at room temperature to obtain a viscous and transparent pale yellow silver-containing polyamic acid (PAA) solution with a viscosity of about 0.80dL/g. Electrospin the silver-containing PAA solution with a voltage of 18kV, a receiving distance of 20cm, a temperature of 25°C, and an air humidity of 40% to obtain a silver-containing PAA spun fiber; then 100, 120, 160, 220 Treated for 0.5h and imidized at 300℃ for 2h (heating rate of 5℃/min) to prepare PI/Ag nanofibers. Refer to the same method to prepare PI nanofibers as a control.
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