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Electrospinning nanofibers

Electrospinning nanofibers. Chitosan [poly(b-1/4)-2-amino-2-deoxy-D-glucopyranose] is a polycationic property that has a partial or total effect by incorporating chitin into the cell wall of oysters and some fungi will. Deacetylation in alkaline medium is a biopolymer. Many researchers have found that chitosan is often preferred in biomedical applications due to its biocompatibility, biodegradability, non-toxicity, potential for cell adhesion and proliferation, antimicrobial activity, and its aid in rapid wound healing. However, chitosan can be produced in the form of powder, gel, foam, film, fiber and thread and used in many different forms in many fields (Tikhonov et al., 2006; Peter, 1996; Rao and Sharma, 1994; Rinaudo, 2006) . It is one of the synthetic polymers with mechanical and physical properties, biocompatible and biodegradable.

Electrospinning nanofibers

It is generally obtained by ring-opening polymerization of “ε-caprolactam”. It has a very wide range of uses, especially in the textile industry. Electrospinning can be briefly defined as the production of submicron fineness fibers by the application of electrostatic forces to a polymer solution or melt. This method includes operational steps such as (i) charging the solution with electric charges (ii) Taylor coning (iii) diluting the polymer jet by instability (whiplash instability) in the electric field (iv) diluting, collecting and solidifying. The polymer jet is converted into fibers on the collection mechanism.

Diameter and morphology of fibers obtained by electrospinning processes, solution properties (viscosity, conductivity, molecular weight and polymer concentration, surface tension, type of solvent), process parameters (electric field strength, distance between feeder and collector, feed amount of solution) and environmental conditions (temperature, humidity) (Chong et al., 2007; Lee et al., 2004). It can be seen that the academic and industry interest in the electrospinning method has increased in recent years as it allows the use of simple and efficient nanofibers. Production of natural and synthetic polymers

Nanofiber-based structures are considered as potential materials, due to their high surface-to-volume ratio, high porosity, and very small pore size (Li and Xia, 2004) As the surface tension increases sharply, electrostatic attraction is said to cause various problems. To overcome this problem, smooth nanofibers can be obtained by blending various polymers.

The chitosan (CS) produced at 2% by weight was dissolved homogeneously in 90% strength acetic acid with stirring for 24 h at room temperature. For 7 hours, homogeneous solution, electrogravity tests were performed. The solutions were mixed using a magnetic stirrer (Stuart, SB 162) for two hours at room temperature. The pH of the prepared solutions was determined using indicator cards (indicator strips, Merck) and their viscosity values. Their conductivity was determined using a Brookfield viscometer (DV-E viscometer). It was measured with a WTW brand device (Cond 3110). A spindle of the type S21 with a rotation of 30 rpm was used for viscometer measurements.

The electrospinning process was performed using a laboratory machine (NanoFMG, NS24) designed on the principle of vertical work. Each solution was transferred to syringes with a volume of 10 ml and introduced into an aluminum foil-covered cylindrical manifold using a 20-gauge delivery unit (nozzle), and the amount of the feed solutions was measured in an electric field of 0.50 ml/hour definitely. And the distance was adjusted to 15 cm. A voltage of 34 kV was applied in electrogravity experiments. Alternating current (AC) was used to create the electric field. The experiments were carried out at a relative humidity of 35-42% and at variable temperatures between 26-31 degrees Celsius.

The polycationic nature of chitosan and the strong intramolecular and intermolecular interactions in its chemical structure create significant problems in the electrospinning process. Strong hydrogen bonds prevent the free movement of polymer chain blocks in the electric field and lead to nozzle cracking during the electrospinning process [Li and Hsieh, 2006; Desai and Keith, 2008). In addition, the repulsive forces between the ionic groups in the polymer chain sufficiently prevent entanglement (entanglement) of the polymer chains. This prevents the formation of sufficient and continuous fibers during stretching, bending and impact instability of the polymer jet. These problems result in the formation of globules or irregular beaded fibers during the elongation of the polymer stream rather than the formation of regular fibers as a result of the electrospinning process.