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- 저자 : 양지우(Jee Woo Yang) (검색결과 6 건)
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지르코니아 나노섬유를 함유한 PAN계 탄소섬유의 제조 및 특성 분석
양지우,유재정,장혜진,용다경,원종성,이승구,Yang, Jee-Woo,Yoo, Jae Jung,Jang, Hae Jin,Yong, Da Kyung,Won, Jong Sung,Lee, Seung Goo 한국섬유공학회 2012 한국섬유공학회지 Vol.49 No.5
There has been steady needs for the PAN based carbon fibers, which have high thermal insulation properties and high mechanical properties. Thus, in this study, low thermal conductive PAN carbon fibers were prepared by using zirconia nanofibers, which were prepared from the electrospinning and sol-gel synthesis of zirconium oxide. Wet spun PAN fibers containing the zirconia nanofibers were stabilized and carbonized in order to prepare the composite carbon fibers. Based on the characterization results using scanning electron microscope (SEM), FT-IR, thermo-gravimetric analysis (TGA), and thermal conductivity measurement, the optimal conditions of composite carbon fibers were established. In addition, the thermal conductivity of prepared composite carbon fibers was reduced considerably by the effects of zirconia nanofiber inclusions.
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광개시제, 올리고머 그리고 Talc 함량에 따른 아크릴계 코팅제의 UV경화 및 박리특성
양지우 ( Jee Woo Yang ),서아영 ( Ah Young Seo ),이철우 ( Chul Woo Lee ) 한국공업화학회 2013 공업화학 Vol.24 No.5
As the usuage of tempered glass for touch panel increased rapidly with the development of industry, the amount of UV curable coating solution used to protect glass surfaces during a tempered glass manufacturing process increased as well. The UV curable coating has advantages compared to thermal curing such as shortened curing time and non-solvent. Appropriated polymer and monomer were used as an acid polymer to grant an alkali peeling ability. The monomers were 2-hydroxyl methylacrylate, 1,6-hexanediol diacrylate and dipentaerythritol hexaacrylate which have acryl groups of 1, 2, and 6, respectively. The combination of three different types of photoinhibitors were used and bisphenol A epoxy diacrylate was used as an oligomer. In this study, experiments were carried out by controlling the amount of photoinitiator, oligomer, and additive while maintaining the constant content of the acid polymer and the acrylic monomer. The changes in physical properties according to the additive content were investigated. It was found that the combination of photoinitiators was necessary to achieve the hardness above 4H and it was possible to control the delamination type of the coating film from a sheet to pieces by the addition of TPO as an initiator. The increase in oligomer contents increased the hardness and adhesiveness alongside dissection time. Talc content of 20 wt% showed the best results.
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MDI 처리 조건에 따른 폴리우레탄 수지와 폴리케톤 직물 사이의 접착특성에 관한 연구
조하니,양지우,임현수,이승구,Jo, Hani,Yang, Jee-Woo,Lim, Hyeon Soo,Lee, Seung Goo 한국섬유공학회 2017 한국섬유공학회지 Vol.54 No.2
Recently developed POK fibers are eco-friendly and economical material compared with other industrial fibers. POK fabric can be applied to awning materials because of its excellent mechanical properties and chemical resistance. In this study, the adhesive strength between polyketone (POK) fabric and polyurethane (PU) resin was investigated by treatment with MDI (methylene diphenyl diisocyanate) which acts as a chain extender on the fabric surface. The MDI treatment conditions of the POK fabric to improve the adhesion of the PU resin were investigated in terms of the amount of materials used and the heat treatment temperature. The changes in chemical structure were analyzed by FTIR. The microstructures of MDI-treated fiber surfaces and fractured surface were observed by FE-SEM. The surface free energy was calculated using contact angles measured with a sessile drop method. The adhesive strength was also analyzed by the T-peel test. Conclusively, by treating the isocyanate groups on the surface of the POK fabric, the bond strength between the POK fabric and the PU resin was more than doubled.
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우레탄 코팅 폴리케톤 직물의 MDI 처리에 따른 열/수분 노화 특성
조하니,양지우,엄서빈,이승구,Jo, Hani,Yang, Jee-Woo,Eom, Seo Bin,Lee, Seung Goo 한국섬유공학회 2018 한국섬유공학회지 Vol.55 No.3
Polyketone is an environmentally friendly material because carbon monoxide produced as a byproduct of other processes can be used as a raw material for its production. Polyketone has excellent heat and impact resistance, and thus it is highly applicable to industrial fabrics, such as waterproof fabrics. On the other hand, polyurethane has been used as a coating material owing to its excellent abrasion, weather, and oil resistance, in addition to being waterproof. The waterproof properties of the fabric depend on the occurrence of defects on the resin-coated surface and the adhesion strength between the coating resin and fabric. In this study, the effects of environmental conditions, including temperature and humidity, on polyurethane-coated polyketone fabric systems were evaluated. The thermal and humid aging behaviors of the polyurethane-coated polyketone fabrics were investigated with methylene diphenyl diisocyanate (MDI) pretreatment. The surface of the polyketone fabric was pretreated with MDI following treatment conditions that were optimized in a previous study. The polyketone fabric was coated with polyurethane and aged under different thermal and humid conditions. In addition to tensile and tear strength measurements, the hydrostatic pressure of the polyketone/polyurethane coating system was measured to evaluate resistance to water penetration. Additionally, the adhesion strength between the polyurethane resin and polyketone fabric after thermal aging was analyzed by the T-peel test, and the fracture surface was observed using SEM. Further, XPS was used to confirm the surface chemical change after thermal aging, and the degree of discoloration of the polyurethane-coated polyketone fabrics after aging was measured with a colorimeter.
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백종규(Jong Gyu Paik),류병태(Byung Tae Rhu),권미라(Mira Kweon),이철우(Cheol Woo Lee),양지우(Jee Woo Yang) 한국추진공학회 2013 한국추진공학회 학술대회논문집 Vol.2013 No.12
B-KNO₃의 노화에 대한 원인을 규명하기위해 B-KNO₃ 점화제의 가속화 시험을 통한 노화특성을 해석하였다. 본 점화제는 미사일 고체 추진제에 사용되는 효과적인 점화제 중 하나로 저압 점화가 용이하고 연소 속도가 비교적 빠르고 안정되며 최대 압력 형성이 균일하다는 장점을 지니고 있다. 그러나 이들 점화제는 보관 방법이나 보관기간에 따라 점화 효율이 저하되는 경향이 있으며 안정된 사용을 위해서는 이에 대한 명확한 이해가 필요하다. 이를위해 미세구조와 결정구조 및 열분석을 통해 환경시험 조건에서 발생되는 변화를 이해하고 이들이 점화 특성에 끼치는 영향성을 규명하였다. 따라서 미세구조와 결정구조 및 열분석을 통해 환경시험 조건에서 발생되는 변화를 이해하고 이들이 점화 특성에 끼치는 영향성을 규명하고자 하였다. 특히 산화제로 첨가된 KNO₃의 내부 구조 변화를 심층 분석함으로써 점화제 노화에 끼치는 산화제 영향을 해석하였다. Aging effects on the B-KNO₃ mixture were investigated by analyzing the results of the accelerated environmental aging tests. The B-KNO₃ system is one of the most effective ignitor which could be applicable for solid rocket propellants of missiles. There are many good properties in B-KNO₃ system for the ignitor such as easy ignition at low pressure, high speed and stable combustion, and uniform formation of maximum pressure. However those ignitor systems showed the degradation in ignition properties depending on the method and period of storage. It should be found out the cause of the degradation. The main cause of the degradation was analyzed by microstructure analysis, XRD analysis and thermal properties analysis using DSC. It was found out that the lattice parameters of the KNO₃ as the oxidizer in the ignition system was changed into original value as the aging time increased. From this study the change of the crystal structure of oxidizer during the storage could be related to the aging properties of ignitor system.
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