• Proceedings of the Optical Society of Korea Conference
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• 2009.10a
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• pp.76-77
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• 2009

• Bulletin of the Korean Chemical Society
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• v.33 no.6
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• pp.2075-2078
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• 2012

• Textile Coloration and Finishing
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• v.8 no.2
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• pp.16-24
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• 1996

Polyester microfiber fabrics were alcoholysed at 120, 140, and 16$0^{\circ}C$ in 0.5, 1.0, and 1.5% of sodiumglycerolate/glycerol solutions(NaGR) up to 80% and the characteristic decomposition features were compared and discussed with the results of the hydrolysis done by 5% sodium hydroxide solution(NaOH) at 80, 90, and 10$0^{\circ}C$. The resulting activation thermodynamic parameters calculated by the combined use of the Arrhenius equation and the Eyring equation were in NaOH case ${\Delta}H^*$=- 13.89 kcal/mol, ${\Delta}S^*$/=-38.12 cal/mol K, and ${\Delta}G^*$=25.25 kcal/mol and in NaGR case ${\Delta}H^*$=29.81 kcal/mol, ${\Delta}S^*$=-2.29 cal/mol K and ${\Delta}G^*$=30.49 kcal/mol. Since in all cases NaGR-PET system has higher activation thermodynamic parameters, it was concluded that NaGR-PET reaction system is more favorable at high temperatures and occurs in a less selective fashion, in comparison to the NaOH-PET reaction system.

• Textile Coloration and Finishing
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• v.9 no.3
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• pp.18-26
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• 1997

Polyester microfiber fabrics were decomposed at 100, 110, and 12$0^{\circ}C$ in saturated CaO/ethylene glycol solutions(CaO/EG), and the characteristics of decomposition kinetics were discussed in comparison to those by hot aqueous hydroxide solution(NaOH). The Arrhenius pre-exponential factor(A) was 9.17x $10^{14}$/M $sec^{-1}$and the activation energy($E_{a}$) was 8.19kcal/mol. While the A value was 1.947x $10^{14}$/M $sec^{-1}$ and the ($E_{a}$ value was about 15~19kcal/mol in NaOH-PET decomposition reaction. The much higher A value of the CaO/EG-PET decomposition reaction means that CaO/EG-PET decomposition reaction will occur in a less selective fashion in comparison to the NaOH-PET decomposition reaction. On the other hand, the lower ($E_{a}$) value of the CaO/EG-PET decomposition reaction than that of the NaOH-PET decomposition reaction means that CaO/EG-PET decomposition reaction is less sensitive on the variation of temperature than NaOH-PET decomposition reaction.

• Clean Technology
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• v.23 no.3
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• pp.270-278
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• 2017

This study introduces a method to easily fabricate highly monodisperse pectin hydrogel microfibers in a microfluidic device by using partial gelation. The hydrodynamic parameters between the pectin aqueous solution and the calcium ions containing oil solution are precisely controlled to form a stable elongation flow of the pectin aqueous solution, and partial gelation of the pectin aqueous solution is performed by the chelating of the calcium ions at the interface between the two phases. The partially gelled pectin aqueous solution is phase-separated from the oil solution in an aqueous calcium chloride solution outside the microfluidic device and is completely gelled to produce monodisperse pectin hydrogel microfibers. The thickness of the pectin hydrogel microfiber is controlled in a reproducible manner by controlling the volumetric flow rate of the initially injected pectin aqueous solution. The pectin hydrogel microfibers were 200 to 500 micrometers in diameter and had a coefficient of variation below 5% under all thickness conditions, indicating that the pectin hydrogel microfibers produced by partial gelation are highly monodisperse. In addition, biomaterials can be immobilized to the pectin hydrogel microfibers produced by a single process, demonstrating the possibility that our pectin hydrogel microfiber can be used as carriers for biomaterials or tissue engineering.

• Proceedings of the Korean Fiber Society Conference
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• 2003.04a
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• pp.293-294
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• 2003

견 피브로인은 대표적인 섬유상 단백질의 하나로 생체적합성, 생분해성, 저독성 등의 유용한 특성을 가지므로 생체재료로 상당한 관심과 연구의 대상이 되어왔다. 우리는 최근의 연구에서 견 피브로인을 생사로부터 추출한 다음, 포름산을 용제로 하여 전기방사함으로써 나노섬유를 제조하고 이들의 각화세포에 대한 친화력을 확인한 바 있다. 본 연구에서는 견 피브로인의 구조체를 나노섬유 부직포, 필름, 마이크로 섬유로 구성된 직물 둥의 형태로 하여 그들의 2차 구조를 비교함과 동시에 구조적 특성이 각화세포와의 친화력에 어떠한 영향을 미치는 가를 비교ㆍ검토 하고자 하였다. (중략)

• Proceedings of the Korean Fiber Society Conference
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• 2002.04a
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• pp.135-138
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• 2002

1990년 초 일본의 Shingosen이 출현하면서 범용화하고 있는 폴리에스테르 섬유가 고부가가치 상품으로 변신하게 되는 계기를 맞게 되었다. 합성 섬유가 갖는 일련의 장점을 유지하면서 천연섬유의 특성을 모방한 폴리에스테르 극세섬유의 등장으로 고급화 및 차별화 된 폴리에스테르 섬유의 상품 추구가 가능하게 되었다. 근래에 와서 통상적인 방법으로 얻어지는 극세사(Micro Fiber)는 약 1d이며, 현재에는 0.3d의 공업적 방사도 가능하게 되었다. (중략)

• Textile Coloration and Finishing
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• v.5 no.3
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• pp.188-193
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• 1993

Aqueous polyurethanes(APU) were prepared from polypropylene glycol(PPG), dimethylol propionic acid(DMPA), and isophoron diisocyanate(IPDI) following a prepolymer mixing process. APUs were applied as binder for nonwoven fabrics processing. APU treated nonwoven fabrics generally showed better tear and tensile strength as compared with the untreated ones. In addition, depending on the soft segment length and crosslinking density of the PU, tear strength of APU treated fabrics was favorably compared with solvent type treated one. Similar results were obtained with microfiber nonwoven fabrics, however, the effect was less significant.

• Proceedings of the Korean Fiber Society Conference
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• 2001.10a
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• pp.71-74
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• 2001

폴리에스테르 섬유는 섬도가 가늘어질수록 전체 표면적이 증가하므로 염색시 초기 염색속도가 빨라져 불균염의 원인이 되며, 겉보기 염착량은 감소하여 많은 염료를 사용해야 된다. 그래서 해도형 초극세 폴리에스테르 섬유는 레규라 폴리에스테르보다 세탁견뢰도 및 습마찰견뢰도가 현저히 저하하게 된다[1-3]. 또한 초극세 폴리에스테르 섬유는 환원세정을 하더라도 마무리 열고정이나 가공시에 가해주는 열로 인해 열이행이 많이 일어나는 것이 세탁견뢰도를 저하시키는 원인으로 지적되고 있다[4, 5]. (중략)

• 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.