Authors: Chun Xue Zhang, Bo Sun
Abstract: Polyacrylonitrile (PAN) ultrafine fiber was prepared by electrospinning of PAN solution made from waste PAN. Diameters of the electrospun fibers as well as distribution of them were characterized by scanning electron microscope. The results show that the waste polyacrylonitrile/ N,N-dimethylformamide solution can be used for electrospinning after simply treatment-filtration. Uniform ultrafine fibers with diameters between 100 nm and 250nm could be obtained. With increasing concentration of waste PAN from 9% to 10%, the morphology was changed from beaded fiber to uniform fiber structure and the fiber diameter was also increased from110nm to 184 nm gradually. A narrow distribution of fiber diameters was observed at a voltage of 22kV. However, more beaded fibers were observed for longer tip–collecting foil distance.
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Authors: Nawinda Chinatangkul, Sirikarn Pengon, Chutima Limmatvapirat, Sontaya Limmatvapirat
Abstract: Electrospun shellac nanofibers might be potentially used for wound dressing application due to its natural origin and excellent protective properties. In this study, a full factorial design with three replicated center points was performed in order to investigate the main and interaction effects of shellac content (35-40% w/w), applied voltage (9-27 kV) and flow rate (0.4-1.2 mL/hr) on the morphology of shellac nanofibers. A total of 11 experiments were conducted. The response variables were the diameter of nanofibers, the distribution of diameter and the amount of beads. The results showed that the concentration of shellac was the most significant impact on shellac nanofiber diameter, while applied voltage, interaction between shellac content and voltage, and feed rate were minor factors, respectively. Shellac content and applied voltage had negative relationships with bead amount. When reducing the concentration of shellac and voltage, the amount of beads was increased. However, the influence of these parameters on diameter distribution seemed to be not significant. Based on response surface plot, nanofibers with thinner diameter (~493 nm) and less number of beads (~0.47) could be obtained at the optimum conditions; the shellac content of 38.5% w/w, the voltage of 21 kV and the feed rate of 0.4 mL/hr.
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