• Macromolecular Research
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• v.14 no.3
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• pp.331-337
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• 2006

In the present study we investigated the relationship between the morphology and mechanical properties of electrospun polysulfone (PSF)/polyurethane (PU) blend nonwovens, by using the electrospinning process to prepare three types of electrospun nonwovens: PSF, PU and PSF/PU blends. The viscosity, conductivity and surface tension of the polymer solutions, were measured by rheometer, electrical conductivity meter and tensiometer, respectively. The electrospun PSF/PU blend nonwovens were characterized by scanning electron microscopy (SEM) and with a universal testing machine. The SEM results revealed that the electrospun PSF nonwoven had a structure consisting of cross-bonding between fibers, whereas the electrospun PU nonwoven showed a typical, point-bonding structure. In the electrospun PSF/PU blend nonwovens, the exact nature of the point-bonding structure depended on the PU contents. The mechanical properties of the electrospun PSF/PU blend nonwoven were affected by the structure or the morphology. With increasing PU content, the mechanical behaviors, such as Young's modulus, yield stress, tensile strength and strain, of the electrospun PSF/PU blend nonwovens were by up to 80%.

• Current Research on Agriculture and Life Sciences
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• v.31 no.1
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• pp.11-17
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• 2013

To investigate the effects of co-solvents on the morphology of nano-scale zein materials, zein solutions were electrospun with different co-solvent ratios of EtOH/$H_2O$. Different zein solution concentrations were used to study the effects of the zein content on the electrospun materials. The resulting electrospun materials were all characterized using field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). The diameters of the electrospun nanoparticles and nanofibers were found to increase when increasing the EtOH ratio at certain zein concentrations. Furthermore, increasing the zein content changed the morphology of the electrospun materials from nanoparticles to nanofibers.

• Polymer(Korea)
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• v.36 no.2
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• pp.196-201
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• 2012

Electrospinning is a versatile process used to prepare micro or nano sized fibers from various materials dissolved in volatile solvents. This study reports electrospun pullulan fibrous webs fabricated through electrospinning using water as a solvent. The electrospinning conditions such as pullulan (PUL) concentration and applied voltage were optimized in order to obtain smooth electrospun fibers. The concentration of PUL greatly influenced the viscosity and surface tension of PUL solution. PUL beaded electrospun fibers were obtained from PUL solutions with concentrations lower than 5 wt%, while homogenous electrospun fibers were prepared from solutions with high concentration and high viscosity. The average diameters of PUL fibers were decreased to 200 nm when the polymer concentration was kept at 10 wt% and the applied voltage was fixed at 15 kV during electrospinning. PUL electrospun fiber exhibited higher solubility, flexibility, softness and adhesive strength.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.258-258
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• 2006

Electrospun fibers of poly(vinyl alcohol) (PVA) were successfully prepared and applied as drug carriers for transdermal drug delivery system. Sodium Salicylate (SS) was the model drug and it was incorporated in the PVA fibers by adding 20 % of SS in a PVA solution prior to electrospinning. Electrospinning of SS-containing PVA solution resulted in the formation of beaded fibers. In order to control the rate of SS release and decrease water solubility of PVA, the SS-loaded electrospun PVA mat was cross-linked by either glutaraldehyde or glyoxal vapor. The morphology, thermal behavior, swelling behavior, release characteristic, kinetics of drug release and also toxicity of the cross-linked sample were investigated.

• Journal of the Korean Ceramic Society
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• v.42 no.8 s.279
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• pp.548-553
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• 2005

$TiO_2$ nanofibers were fabricated by annealing electrospun $TiO_2$/PVP nanofibers for 3 h at $500^{\circ}C$ in air. Size and uniformity of electrospun $TiO_2$ nanofiber diameters were evaluated via XRD and SEM by varying electric field, PVP concentration, Ti tetraisopropoxide concentration and precursor flow rate. Experimental results revealed that the effect of PVP concentration on size and uniformity of electrospun $TiO_2$ nanofiber diameters was most profound, however, the other effects were relatively small. Uniform fibers with no beads were observed for the electrospun anatase titania nanofibers with a diameter of 170 nm.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1869-1874
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• 2003

Polymeric fibers with nanometer-scale diameters are produced by electrospinning. When the electrical forces at the surface of a polymer solution or melt overcome the surface tension then electrospinning occurs. Polyethylene oxide (PEO), Polycarbonate have been electrospun in our laboratory. Electrospun fibers are observed by optical microscopy or scanning electron microscopy. The average diameters of the electrospun fibers range from 300 nm to 30 nm when the electric field strength increasing from 1 kV/cm to 3 kV/cm. The average diameters of the electrospun fibers range from 200 nm to 30 nm when the concentration decreasing from 10 wt% to 4 wt%.

• Journal of the Korean Wood Science and Technology
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• v.43 no.4
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• pp.518-527
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• 2015

In this study, nanocomposite mats consisting of cellulose nanocrystals (CNCs) and poly(lactic acide) (PLA) were electrospun from a suspension mixture consisting of tetrahydrofuran at room temperature. Morphology study showed that fibers of electrospun composite mats were aligned in three dimensional surface along the fiber long-axis. Average diameter of the electrospun fibers decreased with an increase in the CNC loading level. Tensile strength of the electrospun fibers mat decreased with an increase in the CNC loading level because of bead formation in the formed fibers and low interfacial bond strength between PLA and CNC. Meanwhile, thermal stability of the electrospun nanocomposite mats was effectively improved as the amount of CNC increased.

• Transactions of the Korean hydrogen and new energy society
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• v.33 no.2
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• pp.164-175
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• 2022

In this work, sulfonated poly (ether ether ketone) (SPEEK) composite membranes including strontium zirconate (SrZrO₃) were fabricated by the electrospinning method. Fourier-transform infrared spectroscopic analysis and X-ray diffraction analysis were used to identify the chemical structure and the crystallinity of SrZrO₃ and electrospun composite membranes. The thermal stability of the pure SPEEK and SPEEK/SrZrO₃ electrospun composite membranes were investigated by using thermogravimetric analysis. The physicochemical properties and proton conductivity were enhanced with the addition of different weight ratio of SrZrO₃ nanofiller (2, 4 and 6 wt%) in SPEEK polymer. The optimized SPEEK/SrZrO₃-4 electrospun membrane containing 4 wt% of SrZrO₃ showed a high proton conductivity compared to other electrospun SPEEK/SrZrO₃ composite membranes. The results indicate that electrospun composite membranes incorporating these perovskite nanofillers should be explored as potential candidates for use in proton exchange membrane fuel cells.

• Fibers and Polymers
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• v.5 no.2
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• pp.122-127
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• 2004

In this study, we evaluated the effect of the molecular weight of the polymer on electrospun poly(ethylene terephthalate) (PET) nonwovens, and their mechanical properties as a function of the linear velocity of drum surface. Polymer solutions and electrospun PET nonwovens were characterized by means of viscometer, tensiometer, scanning electron microscope(SEM), wide angle X-ray diffraction measurement (WAXD) and universal testing machine (UTM). By keeping the uniform solution viscosity, regardless of molecular weight differences, electrospun PET nonwovens with similar average diameter could be obtained. In addition, the mechanical properties of the electrospun PET nonwovens were strongly dependent on the linear velocity of drum surface. From the results of the WAXD scan, it was found that the polymer took on a particular molecular orientation when the linear velocity of drum surface was increased. The peaks became more definite and apparent, evolving from an amorphous pattern at 0 m/min to peaks and signifying the presence of crystallinity at 45 m/min.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2005.11a
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• pp.153-156
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• 2005

Nondestructive sensing of electrospun PYDF web and multi-wall carbon nanotube (MWCNT)/epoxy composites were investigated using electro-micromechanical technique. Electrospinning is a technique used to produce micron to submicron diameter polymeric fibers. Electrospun PVDF web was also evaluated for the sensing properties by micromechanical test and by measurement electrical resistance. CNT composite was especially prepared for high volume contents, 50 vol% of reinforcement. Electrical contact resistivity on humidity sensing was a good indicator for monitoring as for multifunctional applications. Work of adhesion using contact angle measurement was studied to correlate acid-base surface energy between carbon fiber and CNF composites, and will study furher for interfacial adhesion force by micromechanical test.