• 대한전자공학회논문지
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• 제21권3호
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• pp.39-45
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• 1984

Submicron gratings are fabricated holographically on thin film single mode and multimode waveguides. Thin film waveguides are made by spin-coating polyurethane solution on the substrates of microscope slide glass and Corning 7059 glass. In order to characterize thin film waveguides, the refract사e index and the thickness of thin films are measured by using the m-line spectroscopy. The fabricated gratings are tested as a grating coupler, a mode converter, and a beam splitter. Also chirped gratings are fabricated to observe beam expansion phenomena and thus the possibility of the wavelength demultiplexing.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 춘계학술대회 논문집
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• pp.362-365
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• 1997

In the field of Micro-Mechanics, it has been known diffcult to integrate the micro-machine with sensor and source line for the conventional copper line cnanot be used in compact and small size. We developed a system to make thethin copper film as a connect line on the poyurethane pipe (2mm in diameter) by the evaporation technique. This system consists of an evaporation chamber two long branches, substrate hoider and a Linear-Rotary motion feed feedthrough. The results showed that thin copper film coated polyurethanc pipe could be applied th the small medical devices such as the micro active endoscope.

• 공업화학
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• 제19권4호
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• pp.388-396
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• 2008

2액형 폴리우레탄(Polyurethane)도료는 폴리올과 폴리이소시아네이트가 반응하여 분자간 3차원 망상구조를 형성하기 때문에 도막물성 및 작업성이 매우 우수하여 공업용 소재의 도장용으로 많이 사용하고 있다. 2액형 폴리우레탄도료는 사용목적에 따라 크게 알키드 폴리올, 폴리에스테르 폴리올, 폴리에스테르 변성 아크릴 폴리올 및 아크릴 폴리올로 분류되고 있으며, 수지의 화학적 특성에 따라 반응성 및 건조조건에 따라 도막의 물성차이가 많이 발생하기 때문에 현장적용에 어려움이 있다. 따라서 본 연구는 폴리우레탄 도료의 균일한 반응성 및 물성을 개선하기 위하여 수지의 점도, 용제 및 산가를 동일한 조건으로 하고, 폴리올의 화학적 조성에 따라 분자 중 OH 함유량과 촉매를 다르게 하고, 여기에 폴리이소시아네이트를 경화제로 하여 각각의 반응속도 및 반응 정도를 Rheometer, DMA, FTIR 등을 이용하여 측정하였다. 그 결과 폴리우레탄 도료에서 폴리올과 폴리이소시아네이트와의 반응성은 촉매, 폴리올 중 OH 함유량 및 화학적 조성에 따라 각각 다른 결과를 나타내었으며, 반응 온도 및 촉매에 따라 폴리에스테르 폴리올이 가장 빨랐고, 알키드 폴리올이 가장 늦었다. 그리고 아크릴 폴리올과 변성 아크릴 폴리올은 반응온도 및 촉매에 따라 반응이 다르게 나타났고, OH 함량에 따른 반응성은 OH 함량이 높을수록 빠른 것을 알 수 있었다. 이상의 결과로부터 반응성 및 도막의 물성이 우수한 조건을 선택하면 현장적용의 어려움이 개선될 것으로 판단된다.

• 한국정밀공학회지
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• 제16권3호통권96호
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• pp.62-71
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• 1999

Integrating micro-machined sensors and actuators on the conventional devices with the copper power lines was incompatible to fabricate the mass produced micro electromechanical system (MEMS) devices. To achieve the compatibility of the wiring method between MEMS parts and devices, we developed the three-dimensional sputter-evaporation system that coats micropatterned thin copper films on the surface of the MEMS element. The system consists of a process chamber, two branch chambers, the substrate holder, and a linear-rotary motion feedthrough. Thin copper film was sputtered and evaporated on the biocompatible polymer, Pellethane$^{circed{R}}$ and silicone, catheter that is 2 mm in diameter and 700 mm in length. The metal film coating technique with three-dimensional thin film sputter-evaporation system was developed to apply the power and signal lines on the micro active endoscope. In this paper, we developed the three-dimensional metal film sputter-evaporation system operated on the low temperature for the biopolymeric substrates used in the medical MEMS devices.

• Macromolecular Research
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• 제17권8호
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• pp.616-622
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• 2009

In-depth understanding of the influence of hot pressing and melt processing on the properties of thermoplastic polyurethane (TPU) is critical for effective mechanical recycling of TPU scraps. Therefore, this study focused on the effects of hot pressing and melt mixing on molecular weight (MW), polydispersity index (PDI), melt index (MI), characteristic IR peaks, hardness, thermal degradation and mechanical properties of TPU. The original TPU pellet (o-TPU) showed two broad peaks at lower and higher MW regions. However, four TPU film samples, TPU-0 prepared only by hot pressing of o-TPU pellet and TPU-1, TPU-2 and TPU-3 obtained by hot pressing of melt mixed TPUs (where the numbers indicate the run number of melt mixing), exhibited only a single peak at higher MW region. The TPU-0 film sample had the highest $M_n$ and the lowest PDI and hardness. The TPU-1 film sample had the highest $M_w$ and tensile modulus. As the run number of melt mixing increased, the peak-intensity of hydrogen bonded C=O stretching increased, however, the free C=O peak intensity, tensile strength/elongation at break and average MW decreased. All the samples showed two stage degradations. The degradation temperatures of TPU-0 sample (359 $^{\circ}C$ and 394 $^{\circ}C$)were higher than those of o-TPU (342 $^{\circ}C$ and 391 $^{\circ}C$). While all the melt mixed samples degraded at almost the same temperature (365 $^{\circ}C$ and 381 $^{\circ}C$). The first round of hot pressing and melt mixing was found to be the critical condition which led to the significant changes of $M_n$/$M_w$/PDI, MI, mechanical property and thermal degradation of TPU.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
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• pp.1212-1215
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• 2004

Diffraction modes of holographic grating were fabricated with polyurethane acrylates(PUA). Two types of silica (AEROSIL 200 and AEROSIL R812) were added to reduce the shrinkage of polymer matrix. It was founded that shrinkage of PUA composite film was reduced with the addition of silica. HPDLC based PUA/silica composite also showed high diffraction efficiency. The morphology of the resultant gratings was analyzed by using scanning electron microscopy(SEM) and Tg of the polymer matrix by dynamic mechanical thermal analysis(DMTA).

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 2002년도 봄 학술발표회 논문집
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• pp.289-292
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• 2002

전분을 이용한 환경친화성 고분자 플라스틱 재료에는 전분충진형, blend형 등이 있으나, 대체로 전분은 보조재료로 사용된다. 이에 반해 extruder를 이용한 전분발포체나 TPS (Thermoplastic starch) 등은 전분을 주재료로 사용하여 플라스틱 재료를 만드는 것이지만, TPS 필름의 Tg가 실온보다 높아 glassy 상태의 brittle한 성질로 인해 물성이 낮으며, 수분 친화적인 성질로 인해 플라스틱 재료로서의 사용이 제한되는 단점이 있다[1,2]. (중략)

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 1990년도 춘계공동학술대회논문집; 한국과학기술원; 28 Apr. 1990
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• pp.171-185
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• 1990

In order to measure the shape deformation of seat surfaces, an indentation measurement mat was devised. The 50cm * 50 cm mat containing small polyethylene beads were made using two sheets of polyurethane film. The indentation measurement mat was shaped by vacuuming between the subject and the testing seat. This method showed less than 5mm of deformation measurement error. Deformation of CADILLAC and MAXIMA seats were compared to demonstrate usefulness of the new method.

• 한국기계가공학회지
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• 제21권5호
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• pp.105-109
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• 2022

In the field of medical and marine industries, antibacterial surfaces have been emerged as one of the most important issues. Recently, many researchers have been studying antibacterial surfaces to kill bacteria or prevent the adhesion of bacteria. In their researches, various materials and structures are suggested to inhibit the adhesion of bacteria or kill the attached bacteria. However, chemical materials such as antibiotics or metal could be toxic. Moreover, frequent use of antibiotics causes super bacteria having resistance to antibiotics. In this study, nano-pillar structured surface was fabricated using polyurethane acrylate (PUA) and the mechanically induced antibacterial function was confirmed based on the fabricated nanostructures. Nanostructures can damage the bacterial membrane of Gram-negative bacteria through stretching of bacterial membrane via interaction with the nanostructures and the bacterial membrane. Consequently, the proposed transparent, flexible and nanostructured PUA films can be one of promising candidates for antifouling and antibacterial surfaces which can be applied in various industries.

• 한국염색가공학회지
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• 제32권3호
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• pp.176-183
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• 2020

In order to study wearable air cushion materials capable of responding to massive impact in high-altitude fall situation, high tenacity woven fabrics were bonded by heat only depending on various type of thermoplastic films and then mechanical properties were measured. Tensile strength, elongation, and 100% modulus measurement results for 4 types of films show that TPU-2 has higher impact resistance and easier expansion than PET-1. After thermal bonding, the combination with the highest tensile strength was a material with a TPU-2 film for nylon and a PET-2 film for PET, so there was a difference by type of fabric. The tear strength of the bonded materials were increased compared to the fabric alone, which shows that durability against damage such as tearing can be obtained through film adhesion. All of the peel strengths exceeded the values required by automobile airbags by about 5 times, and the TPU-2 bonded fabric showed the highest value. The air permeability was 0 L/dm2 /min. For both the film and the bonded material, which means tightness between the fabric and the film through thermal bonding. It is expected to be applied as a wearable air cushion material by achieving a level of mechanical properties similar to or superior to that of automobile airbags through the method of bonding film and fabric by thermal bonding.