• Bulletin of the Korean Chemical Society
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• v.34 no.12
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• pp.3733-3737
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• 2013

Polyacrylonitrile (PAN)-based ultrafine fibers and carbon fibers were produced by wet-spinning, and the crystal sizes and thermal and mechanical properties of the fibers were investigated. Scanning electron microscopy revealed that the superfine fibrils in the surfaces of the PAN/polyvinyl acetate (PVA) blend fibers increased slightly with increasing PAN content before removal of the PVA. Differential scanning calorimetry indicated that the PAN and PVA in the blend fibers do not mix and, therefore, each maintains their inherent thermal characteristics. The crystal sizes of the blend fibers prepared by removing PVA with water increased at 5 wt % water. The extent of the reaction of the PAN carbon fibers, as calculated from the FT-IR spectra, is maximized at the stepwise temperature of $230^{\circ}C$, and the density increased significantly above this temperature. The carbon fibers had relatively good mechanical properties, as shown by their tensile strength and modulus values of 2396 MPa and 213 GPa, respectively.

• Fiber Technology and Industry
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• v.1 no.3
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• pp.362-368
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• 1997

• Textile Coloration and Finishing
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• v.22 no.4
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• pp.325-331
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• 2010

The alkaline dissolution behavior of sea-island type ultrafine nylon fiber were dependent on the concentration of NaOH and treatment time, and the most appropriate condition for alkaline dissolution was to treat with 20g/l NaOH for 30 min at $80^{\circ}C$. The dyeing properties of sea-island type ultrafine nylon fiber and regular nylon fiber were examined with 3 different types of acid dyes in this study. The dye uptakes of ultrafine nylon fiber were higher than regular nylon fiber because of large surface area per unit mass, which increased as the dye bath pH decreased. The dyeing rates on ultrafine nylon fiber were faster and dye exhaustions were higher than regular nylon fiber, however color strength and rating of wash fastness were lower. It was also found that levelling type acid dye showed fast dyeing rate on both nylon fibers than metal-complex and milling type acid dyes.

• Applied Chemistry for Engineering
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• v.17 no.3
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• pp.255-259
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• 2006

Ultrafine fibers having approximately 800 nm diameter were prepared by an electrospinning method from cellulose acetate. Cellulose acetate dissolved in acetone solutions were electrospun at various conditions. The cellulose polymer solutions of various concentrations were applied under different voltages, flow rates, and tip-to-collector distances (TCD). The diameter of fibers depended on the electrospinning parameters such as its viscosity. The fibers were not formed from the polymer solutions less than 12.0 cP viscosity. The minimum diameter was 800 nm at 12.5 wt% of polymer concentration, 12 kV of voltage, $100{\mu}L/min$ of flow rate, and 7.5 cm TCD.

• Proceedings of the Korean Fiber Society Conference
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• 1998.10a
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• pp.406-409
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• 1998

Sound absorbing materials are divided into several types according to the appearances and the characteristics. Basic mechanism of sound absorption in various sound absorbing materials is the conversion of sound energy into hat energy. Here the important elements which govern by the conversion from sound into heat depend on the type of materials. (omitted)

• Proceedings of the Korean Fiber Society Conference
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• 2003.10b
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• pp.271-272
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• 2003

Electrospinning is a novel process for forming fibers with submicron scale diameters through the action of electrical force. In the previous study, we performed study on the ultrafine PVDF nanofiber production in the stable spinning condition. Recently it would be great interest to fabricate IP(inorganic particle) assemblies in nanofibe. since such IP/nanofiber hybrid materials might be used in a nonwoven form as nanowires, medical gauges for bums healing and cell growing, sensors, chemical and gas filteration. (omitted)

• Macromolecular Research
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• v.17 no.7
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• pp.533-537
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• 2009

This paper introduces a modified electro spinning system for biomedical wound-healing applications. The conventional electrospinning process requires a grounded electrode on which highly charged electro spun ultrafine fibers are deposited. Biomedical wound-healing membranes, however, require a very low charge and a low level of remnant solvent on the electrospun membrane, which the conventional process cannot provide. An electrohydrodynamic process complemented with field-controllable electrodes (an auxiliary electrode and guiding electrodes) and an air blowing system was used to produce a membrane, with a considerably reduced charge and low remnant solvent concentration compared to one fabricated using the conventional method. The membrane had a small average pore size (102 nm) and high porosity (85.1%) for prevention of bacterial contamination. In vivo tests on rats showed that these directly electro spun fibrous membranes produced using the modified electro spinning process supported the good healing of skin bums.

• Proceedings of the Korean Fiber Society Conference
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• 2003.10b
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• pp.275-276
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• 2003

Electrostatic spinning or electrospinning has been recently paid attention to prepare ultrafine fiber mats which are composed of diameters in a range of submicrons to nanoscale size[l]. Due to small diameters and porous structure, electrosun fibers have a high specific surface area and expected to use for broad applications, such as filters, membranes, wound dressing materials, artificial blood vessels. a nonwoven fabric, a reiforcement of nanocomposites[2,3], etc. (omitted)

• Proceedings of the Materials Research Society of Korea Conference
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• 2010.05a
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• pp.44.1-44.1
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• 2010

poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) is a bacterially derived copolymer produced by fermentation. PHBV has been attractive because of its potential environmental, pharmaceutical and biomedical applications. Recently, the electrospinning technique has been used to fabricate fibrous mat for biomedical applications such as artificial blood vessel, drug release and scaffolds, because this method is simple and easy to get ultrafine polymer fibers. Depending on speed of rotation drum collector, fiber structure was different. In this work, PHBV fiber was aligned by electrospinnning machine. Furthermore, alignment of PHBV fiber mats was given angle such as $45^{\circ}$, $60^{\circ}$ and $90^{\circ}$. The morphology of each aligned PHBV fiber mat was observed by SEM technique. The mechanical property was evaluated depending on alignment angle. Especially, cell attachment ability depending on alignment of PHBV fiber mats was carried out using MG- 63 osteoblast like cells.

• Macromolecular Research
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• v.13 no.6
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• pp.521-528
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• 2005

Electrospun polyacrylonitrile (PAN) nanofibers were carbonized with or without iron (III) acetylacetonate to induce catalytic graphitization within the range of 900-1,500$^{circ}C$, resulting in ultrafine carbon fibers with a diameter of about 90-300 nm. Their structural properties and morphologies were investigated. The carbon nanofibers (CNF) prepared without a catalyst showed amorphous structures and very low surface areas of 22-31 $m^{2}$/g. The carbonization in the presence of the catalyst produced graphite nanofibers (GNF). The hydrogen storage capacities of these CNF and GNF materials were evaluated through the gravimetric method using magnetic suspension balance (MSB) at room temperature and 100 bar. The CNFs showed hydrogen storage capacities which increased in the range of 0.16-0.50 wt$\%$ with increasing carbonization temperature. The hydrogen storage capacities of the GNFs with low surface areas of 60-253 $m^{2}$/g were 0.14-1.01 wt$\%$. Micropore and mesopore, as calculated using the nitrogen gas adsorption-desorption isotherms, were not the effective pore for hydrogen storage.