• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 추계학술대회 논문집
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• pp.667-668
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• 2006

• 한국생산제조학회지
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• 제23권2호
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• pp.127-132
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• 2014

Micro/nano-injection molding is one of the main processing techniques for polymer micro-fabrication. Most of the difficulties encountered in polymer micro-molding are caused by the demolding, rather than the filling of molds. Therefore, studying the demolding process is vitally important for manufacturing polymer replicas. The most important parameters are the thermal stress, friction and adhesion forces, and mechanical strength of the resist. In this research, we determinedthe effects of the processing conditions on the ejection force for cases involving two common thermoplastic polymers. The results showed that the processing conditions noticeably influenced the ejection force.

• Tribology and Lubricants
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• 제22권4호
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• pp.182-189
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• 2006

In this paper, the adhesion characteristics between a fused silica without or with an anti-sticking layer and a thermoplastic polymer film used in thermal NIL were investigated experimentally in order to identify the release performance of the anti-sticking layer. The anti-sticking layers were derived from fluoroalkylsilanes, (1H, 1 H, 2H, 2H-perfluorooctyl)trichlorosilane ($F_{13}-OTS$) and (3, 3, 3-trifluoropropyl)trichlorosilane (FPTS), and coated on the silica surface in vapor phase. The commercial polymers, mr-I 7020 and 8020 (micro resist technology, GmbH), for thermal NIL were spin-coated on Si substrate with a rectangular island which was fabricated by conventional microfabrication process to achieve small contact area and easy alignment of flat contact sur- faces. Experimental conditions were similar to the process conditions of thermal NIL. When the polymer film on the island was separated from the silica surface after imprint process, the adhesion force between the silica surface and the polymer film was measured and the surfaces of the silica and the polymer film after the separation were observed. As a result, the anti-sticking layers remarkably reduced the adhesion force and the surface damage of polymer film and the chain length of silane affects the adhesion characteristics. The anti-sticking layers derived from FPTS and $F_{13}-OTS$ reduced the adhesion force per unit area to 38% and 16% of the silica sur-faces without an anti-sticking layer, respectively. The anti-sticking layer derived from $F_{13}-OTS$ was more effective to reduce the adhesion, while both of the anti-sticking layers prevented the surface damages of the polymer film. Finally, it is also found that the adhesion characteristics of mr-I 7020 and mr-I 8020 polymer films were similar with each other.

• 패션비즈니스
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• 제8권5호
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• pp.115-124
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• 2004

PTT(polytrimethylene terephthalate) is a thermoplastic that can be melt-spun into fibers and has extensive applications in carpets, textiles and apparel, engineering thermoplastics, nonwovens, and films or sheets. This polymer combines the good properties of nylon and polyester. Compared with other synthetic fibers such as nylon and acrylic, the PTT fibers feel softer, dye easier with vibrant colors, stretch and recover better. Moreover, the PTT fibers for carpets resist most stainings, clean better, and dry faster. The PTT was first patented in 1941, but it was not until the 1990's, when Shell Chemicals developed the practical method of producing PDO, the raw material for PTT. Many studies have been done including the retention of carpet texture using an image analysis technique, or compressional resilience of the carpet for long term use. In this study, PTT and nylon BCF carpets were compared in terms of the compressional properties including the resilience, using one of the KES system for repetitive measurements. The compression resilience(RC) values of the PTT BCF carpets far exceed those of nylon 6 BCF carpets. The RC values of the PTT BCF carpet(cut) specimens are $42{\sim}45%$ for 5 successive compression deformations, while those of the nylon BCF carpet specimens(cut) are $26{\sim}28%$. There is also a similar trend in the RC values for the other type of carpet which is the loop type. This resilience is one of the important factors of carpet usage evaluation.

• Elastomers and Composites
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• 제45권3호
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• pp.217-222
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• 2010

여름철 아스팔트의 표면 온도 상승으로 인한 도로의 소성변형과 겨울철 온도 강하로 인한 도로균열이 도로안전 운전을 위협하는 문제로 등장하면서 아스팔트 물성향상을 위한 아스팔트개질의 필요성이 대두되고 있다. 본 연구에서는 아스팔트의 탄성과 소성변형저항성을 증가시키기 위해 아스팔트 물성 노화의 직접적 원인인 햇빛, 특히 자외선을 이용하기 위해, 고분자중합에 사용되는 광개시제를 사용하여 고분자로 개질된 아스팔트를 다시 개질하였다. 인장시험기와 레오미터를 이용하여 기계적 물성과 유변학적 물성을 실험한 결과 열가소성고분자개질아스팔트는 자외선에 의한 가교반응으로 인해 인장강도와 저장탄성률이 크게 증가하였으나 열경화성고분자개질아스팔트에는 영향을 끼치지 못하였다. 장시간 자외선조사 시험에서는 조사시간이 길어짐에 따라 그 물성이 증가되거나 유지되는 거동을 보임으로써 자외선이 아스팔트의 사용수명이 20년이 될 수 있는 효과를 나타내었다.