• Polymer(Korea)
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• v.38 no.4
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• pp.518-524
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• 2014

Electrospinning has gained interests as a polymer processing technique for nanofiber fabrications. It is well known that both polymer solutions and polymer melts can be electrospun. Among them, melt electrospinning is environmentally friendly technique due to the absence of solvent. However, the diameter of melt-electrospun fibers is typically thicker than solution-electrospun fibers. By using a home-made melt-electrospinning device, micron-sized fibers with smooth and even surfaces were electrospun successfully. We demonstrate that low-density polyethylene fibers can be reduced in diameter with a viscosity-reducing additive such as low molecular weight polyethylene monoalcohol and polyethylene wax. The diameter was further reduced by blending it with oxidized polyethylene wax due to polarity increment. Additionally, parameters affecting the diameter were analyzed such as an applied voltage and a spinning distance.

• Korean Chemical Engineering Research
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• v.55 no.1
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• pp.68-73
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• 2017

The removal of particulate matter ranging from $0.01{\mu}m{\sim}10{\mu}m$ can be performed by using membrane filters composed of fibers. Electrospinning techniques offer the production of very thin fibers with a uniform fiber diameter over conventional techniques including template synthesis, melt-blown, phase separation, etc. Air filtration will be improved with electrospun membranes due to the open pore structures, high porosity, and large surface area of the membranes. In the present study, filtration efficiency increased with pore size decrease and fiber density increase induced by carbon nanotube and the increased CA (cellulose acetate) concentration during electrospinning process.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.1
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• pp.41-48
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• 2017

Fine polymeric fibers have been gaining interest from the energy harvesting/storage, tissue, and bioengineering industries because of advantages such as the small diameter, high porosity, permeability, and similarities to a natural extracellular matrix. Electrospinning is one of the most popular methods used to fabricate polymeric fibers because it is not as limited in regards to the materials selection, and it does not require expensive or complex equipment. However, electrospun fibers have a severe aerodynamic instability because the small diameter fibers are able to pass through the atmospheric layer when there is a high electric field. As a result, electrospun fibrous mats have serious difficulties with controlling its shape and geometric properties. In this study, a hybrid nano/microfibrous mat is presented that is fabricated using electrospinning with two different solvent-based PCL solutions. This provides control of the fiber diameter, mat porosity, and mechanical properties. Various hybrid fibrous mats were fabricated after an experimental investigation of the effects of solvent on fiber diameter. It was then demonstrated that the mechanical properties and porosity of the fabricated various hybrid mats could be successfully controlled.

• Science of Emotion and Sensibility
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• v.19 no.3
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• pp.43-50
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• 2016

The uniform nanofibers of polyurethane with different contents of Juniperus Chinensis extracts were successfully prepared by electrospinning method. Polyurethane is widely used as functional polymers in the industrials, medical field as their properties can be tailor-made by adjusting their compositions. Juniperus Chinensis has been reported for anti-tumor, anti-bacterial, anti-fungal, and anti-viral activities. PU/Juniperus Chinensis extracts composite nanofibers were produced at different Juniperus Chinensis extracts concentrations (0.25, 0.5, 1, 1.5wt.%). The effects of the major parameters in electrospinning process such as tip to collector distance (TCD), voltage, polymer concentration on the average diameter of electrospun nanoweb were investigated. As results, 12wt% PU solution concentration, 8kV applied voltage and 15cm tip to collector distance were identified as optimum conditions for electrospinning the composite nanofibers. The diameter and morphology of the nanocomposite nanofibers were confirmed by a scanning electron microscopy (SEM). The resulting fibers exhibited a uniform diameter ranging from 435nm~547nm. It has been found that the average diameters of fibers decreased by the adding of Juniperus Chinensis extracts. These nanowebs can be used for medical materials, protective clothing, and antimicrobial filters.

• Science of Emotion and Sensibility
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• v.13 no.2
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• pp.391-402
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• 2010

In this study, breathable waterproof materials were prepared by electrospinning. Five kinds of electrospun nanofiber web layered systems with different levels of nanofiber web density, as well as different substrates and layer structures were fabricated, and their mechanical properties (tensile, bending, shear, compression, surface, and thickness & weight) were measured by the KES-FB system and compared with those of conventional breathable waterproof fabrics (densely woven fabric, PTFE laminated fabric and PU coated fabric). The KES-FB measurements demonstrate that the lab-scale nanofiber web layered systems are more flexible and fuller than commercial nanofiber web layered systems, which have a more compact structure than the lab-scale nanofiber web layered systems. Densely woven fabrics and lab-scale nanofiber web layered systems showed lower values of tensile linearity (LT), bending stiffness (B), and shear stiffness (G) than those of PU coated and PTFE laminated fabric. These results indicate that they are more flexible and have less resistance to the shearing movement, corresponding to a more pliable material having a better drape, than PU coated fabrics and PTFE laminated fabrics.

• Science of Emotion and Sensibility
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• v.19 no.2
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• pp.35-42
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• 2016

Electrospinning is a simple and effective process for producing nanofiber with diameter range from nanometers to micrometers which have high specific surface area. Hence, medicated nanofibers can be readily fabricated using a solution containing a mixture of a plant-extracts and a polymer. It has proved that Juniperus Chinensis can be effectively used for the prevention of UV and SLS-induced advers skin reaction such as radical production, inflammation and skin cell damage. It also found that Juniperus Chinensis has efficient ingredient of antifungal activity and house dust mite repellent effect. The fabrication of PVA nanofibers containing Juniperus Chinensis extracts by electrospinning has been studied. PVA/Juniperus Chinensis extracts composite nanofibers were produced at different Juniperus Chinensis concentrations (0.25, 0.5, 1.5 wt. %). The parameters of electrospinning including polymer contents, voltage and tip-to-collector distance (TCD) were optimized for fabrication process. The study show that 12 wt. % PVA, 10kV applied voltage and TCD 10~20 cm are the best condition to obtain uniform PVA/Juniperus Chinensis extracts composite nanofibers. Morphologies of the electrospun composite nanofiber were observed by using a field emission scanning electron microscope. It has been found that the average diameters of fibers increased by the adding of Juniperus Chinensis extracts. As the results, PVA/Juniperus Chinensis extracts composite nanofibers having a diameter in the range from 310~360 nm were successfully prepared via an electrospinning.

• Proceedings of the Korean Fiber Society Conference
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• 2002.04a
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• pp.263-264
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• 2002

무정형 고분자인 폴리카보네이트는 투명하고 뛰어난 기계적 성질(특히 내충격성) 내열성 내한성ㆍ전기적 성질을 균형 있게 갖추고, 무독하고 자기소화성(自己消火性)도 있는 엔지니어링 플라스틱이다. 본 연구의 목적은 이러한 특성을 가지는 폴리카보네이트를 이용하여 전기방사법으로 sub-micron의 섬유직경으로 구성된 부직포를 제조하는데 있다. (중략)

• Proceedings of the Korean Fiber Society Conference
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• 2003.04a
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• pp.388-389
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• 2003

전기방사를 이용하여 나노섬유를 제조하려는 많은 연구가 진행되고 있다. 고분자 재료 측면에서 피브로인, 키토산, 콜라겐 등 천연고분자는 생분해성, 생체적합성, 환경친화성이 뛰어나 이들을 나노섬유소재로 개발할 경우 의료용소재 뿐만아니라 생명공학소재로서의 이용가능성이 크다. 특히, 실크피브로인은 생체적합성, 산소투과능, 세포부착능 둥 생체재료로서의 성능뿐만 아니라 우수한 물성과 기계적 성질을 가지고 있으므로 다양한 형태로 성형화시킴으로써 소재 성능을 높일 수 있다. (중략)

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2017.05a
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• pp.168.2-168.2
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• 2017

발열체는 전기 에너지를 열 에너지로 변환시키는 전기 저항체인데, Ni-Cr계 합금이 발열 가능 온도가 범위가 크고 열 효율 및 내 산화성, 내 부식성이 우수하여 발열체로 많이 사용되고 있다. 그리고 기존의 선형 발열체의 효율성을 개선한 면상 발열체가 개발되었고, 최근 나노 기술의 발달로 나노크기의 ITO(Indium Tin Oxide) 입자나 탄소나노튜브가 코팅된 형태의 투명 면상 발열체가 개발되어 주목을 받고 있다. 투명 면상 발열체는 발열체의 형태를 거시적으로 확인할 수 없기 때문에 자동차의 전면 유리 히터 및 건축용 기능성 창호 등의 심미적 효과를 요구하는 제품에 사용될 수 있다. 본 연구에서는 PVP(Poly vinyl Pirrolidone)을 이용하여 Ni-Cr Nanofiber 제조를 위한 효율적인 전기 방사 조건을 도출한다. PVP 질량에 따라서 Ethanol과 Methanol, 물을 이용하여 viscosity와 ion conduciviy를 조절하였고, 전기방사 조건으로 bead를 최소화 하는 나노섬유를 얻었다. 이어서 Ni-Cr/PVP 용액은 Metal Precursor wt.% 조절 및 방사조건으로 100~300nm의 직경을 가진 나노 섬유를 얻을 수 있었다. 산화/환원 열처리 후 PVP와 Oxide가 제거된 Ni-Cr nanofiber를 합성하였다. Nanofiber 형상은 FE-SEM으로 측정하였으며, XRD, FT-IR 분석을 통해 제작된 나노 섬유의 구조적 특성을 확인하였다.

• Proceedings of the Korean Fiber Society Conference
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• 2001.10a
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• pp.348-350
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• 2001

Polyurethane(PU)은 내마모성, 내약품성, 내용제성이 좋으며 내노화성과 산소에 대한 안정성이 뛰어난 고분자로서 spandex를 비롯하여 코팅, 고무, 도료, 플라스틱, 복합재료 등의 여러 분야에서 이용되어지며 PU를 전기방사 하여 얻은 부직포는 wound dressing, anti-bacteria mask, 인조 피혁, stent 등에 이용할 수 있을 것으로 기대된다. (중략)