• Elastomers and Composites
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• v.40 no.4
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• pp.258-265
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• 2005

To study the compressive stress, recovery force and permanent strain of foams for footwear midsole, polyurethane(PU), phylon(PH) and injection phylon(IP) foams were repetitively compressed with constant compressive stress. Maximum compressive stress of PU did not decrease with repetitive compression on the constant compressive stress, but that of IP largely decreased. Engineering strain of foams were formed by repetitively compressing the three types of foam. The engineering strain of PU was smaller than that of IP and PH. Compressive stress and recovery force of IP and PH at certain strain were decreased with repetitive compression, but that of PU was not noticeably changed.

• Elastomers and Composites
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• v.43 no.2
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• pp.124-132
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• 2008

Thermal and mechanical properties of flexible polyurethane foam modified by urushiol and cardanol which have been known to be antibiotic were investigated. It was observed from FT-IR spectra analysis that the urushiol reacted with isocyanate was participated in synthesis of polyurethane. It was also seen that the modification using urushiol and cardanol made the PU more thermally stable without deterioration of mechanical properties. The modified PU foams showed increased antibacterial properties compared with neat PU foam.

• Clean Technology
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• v.20 no.3
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• pp.277-282
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• 2014

In this study, PU-LMO was made by immobilization of LMO on urethane foam (PU) with using an EVA as a binder. PU-LMO was characterized by using X-Ray Diffractometer (XRD) and Scanning Electron Microscopy (SEM). The optimal ratio of EVA/LMO for preparation of PU-LMO was 0.26 gEVA/gLMO. The adsorption of lithium ions by PU-LMO was found to follow the pseudo-second-order kinetic model. The equilibrium data fitted well with Langmuir isotherm model and the maximum removal capacity of lithium ions was 17.09 mg/g. The PU-LMO was found to have a remarkably high selectivity of lithium ions and high adsorption capacity because the distribution coefficient ($K_d$) of lithium ion was higher than those of other metal ions.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2012.03a
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• pp.102-102
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• 2012

수분산 폴리우레탄 수지는 기능성이 뛰어나고 다양한 용도로 쓰임이 많기 때문에, 용제형 폴리우레탄 수지를 이용한 환경문제에 대처할 수 있는 대안으로 그 쓰임이 점차 늘어나고 있다. 그러나 수분산 폴리우레탄 수지는 용제형 폴리우레탄 수지에 비해 물리적 특성이 떨어지는 단점이 있다. 그래서 우수한 물리적 특성을 유지하면서 용제형 폴리우레탄 수지를 대체할 수 있는 환경친화성 폴리우레탄 수지에 대한 연구가 많이 이뤄지고 있다. 최근 산업환경 변화에 순응하는 환경 친화적 소재를 사용하여 자동차, 선박, 철도 등 수송용 인테리어 내장재를 구성하는 기술로서, 난연성 및 기계적 물성 유지 기술, 그리고 실내 쾌적감을 부여하기 위한 감성기술 및 심미적 요소를 부여하는 디자인 기술이 가미된 복합 기능화 기술개발이 요구되고 있다. 기존의 자동차용 시트 제품의 대부분은 습식 PU와 PVC를 사용하고 있고, 제조과정에서 용제와 가소제 사용 등으로 인해 환경적으로 많은 문제점이 있으며, 이를 대체하기 위한 노력이 많은 부분에서 이루어지고 있지만, 마땅히 대체할 소재를 찾지 못하고 있는 실정이다. 본 연구에서 제안하는 Frothing 기법을 이용한 친환경 foam 제조기술은 기존의 습식 PU foam과 PVC foam을 대체할 수 있는 기술로서, PUD foam의 기계적 물성 및 가공성이 보완된다면 상업적 용도로 많은 분야에서 활용될 것으로 판단된다.

• Korean Journal of Materials Research
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• v.23 no.7
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• pp.366-372
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• 2013

Flexible polyurethane/clay porous nanocomposite foams were synthesized using natural and organically modified montmorillonite clays such as bentonite, closite 10A and closite 30B. The content of nanoclays was varied from 1 to 5 wt% of polyol. Dispersion of clay in Polyurethane(PU) matrix was investigated by X-ray diffraction(Cu-$K{\alpha}$ rays of wavelength $1.54{\AA}$) using an X-ray diffractometer. Also, we determined that the thermal resistance of PU foam increased with added clay, compared to that of pure PU foam. The cell size and the fraction of open cells of the precursor foam were controlled by the addition of clay to the polyurethane foam. Modified clays were found to be more efficient cell openers than the unmodified clay. In addition, the tensile strength and elongation of the polyurethane/clay porous nanocomposites were examined. Increasing clay content increased the mechanical properties of the composites, such as tensile strength, and elongation at break. However, increasing the content over 5 wt% deteriorated the properties of the composites. We found that the nanofillers(bentonite, closite 10A and closite 30B) improved the thermal stability of the nanocomposite foam. The nanocomposite foam containing 3 wt% of closite 30B exhibited the best tensile strength and thermal stability.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2012.03a
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• pp.19-19
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• 2012

최근 산업환경 변화에 순응하는 환경 친화적 소재를 사용하여 자동차, 선박, 철도 등 수송용 인테리어 내장재를 구성하는 기술로서, 난연성 및 기계적 물성 유지 기술, 그리고 실내 쾌적감을 부여하기 위한 감성기술 및 심미적 요소를 부여하는 디자인 기술이 가미된 복합 기능화 기술개발이 구되고 있다. 기존의 자동차용 시트 제품은 대부분 PU Foam을 시트원단에 불꽃으로 Lamination 하는 방식으로 제조되었으며, 이러한 제조 방식은 많은 공정을 거치게 되고 PU Foam을 제조하는 공정 및 불꽃으로 Lamination 하는 공정에서 많은 환경유해가스가 발생하는 등 환경적으로도 많은 문제점을 감수하면서 생산하는 방식이다. 또한 각종 원단의 표피재로 많이 사용되고 있는 PU와 PVC의 경우 제조과정에서 용제와 가소제 사용 등으로 인해 환경적으로 많은 문제점이 있으며, 이를 대체하기 위한 노력이 많은 부분에서 이루어지고 있지만, 마땅히 대체할 소재를 찾지 못하고 있는 실정이다. 본 연구에서 제안하는 실리콘수지는 기존의 PU와 PVC를 대체할 수 있는 소재로서 각광받고 있으며, 응용기술 개발을 통해 충분히 적용이 가능한 소재라고 판단된다. 본 연구에서 개발하고자 하는 기술은 난연성을 가진 실리콘 내장 표피재에 불꽃으로 Lamination하는 공정을 배제한 친환경 PUD Foam을 바로 Back Coating함으로써 일체형 고 기능 친환경 제품을 개발함으로써 친환경 복합화 기술 및 SEAT 원단과 표피재의 일체형 모듈화 공법개발을 이루고자 한다.

• Journal of Biomedical Engineering Research
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• v.24 no.1
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• pp.31-36
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• 2003

Impact characteristics of six DM(Diabetes Mellitus) shoe insole materials (Podian, Plastazote black, Plastazote white, Flexible PU foam, Podialene 200 blue and Podia flex) and three multi-density insoles (AP, OS and PW insoles) were determined in the present study, using a self-designed impact measurement system. The coefficient of restitution, the median frequency and the attenuation index were calculated for each material, based on impact forces and linear accelerations. Podian revealed the superiority in the coefficient of restitution and the attenuation index. The median frequency of the Flexible PU foam was the smallest. Results also showed that the heel region was the most impact-attenuated among other areas in the insole. OS insole showed the better characteristics in the coefficient of restitution and the median frequency. but there was no significant difference in the attenuation index. Similar impact characteristics were found in all areas in PW insole. since it was basically of the same dual-density polyurethane.

• Journal of Powder Materials
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• v.20 no.6
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• pp.439-444
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• 2013

Fe foam with above 90% porosity and 2 millimeter pore size was successfully fabricated by a slurry coating process. In this study, the binder contents were controlled to produce the Fe foam with different pore size, strut thickness and porosity. Firstly, the slurry was prepared by uniform mixing with Fe powders, distilled water and polyvinyl alcohol(PVA) as initial materials. After slurry coating on the polyurethane(PU) foam the sample was dried at $80^{\circ}C$. The PVA and PU foams were then removed by heating at $700^{\circ}C$ for 3 hours. The debinded samples were subsequently sintered at $1250^{\circ}C$ with holding time of 3 hours under hydrogen atmosphere. The three dimensional geometries of the obtained Fe foams with open cell structure were investigated using X-ray micro CT(computed tomography) as well as the pore morphology, size and phase.

• Elastomers and Composites
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• v.58 no.4
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• pp.208-215
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• 2023

In this study, the properties of polyurethane-polydimethylsiloxane (PU-PDMS) hybrid foams containing different types and contents of physical blowing agents (PBAs) were investigated. Two types of blowing agents, namely physical blowing agents and thermally expandable microspheres (TEM), were applied. The apparent density was measured using precisely cut foam samples, and the pore size was measured using image software. In addition, the microstructure of the foam was confirmed via scanning electron microscopy and transmission electron microscopy. The thermal conductivities related to the microstructures of the different foams were compared. When 0.5 phr of the hydrocarbon-based PBA was added, the apparent density and pore size of the foam were minimal; however, the pore size was larger than that of neat foam. In contrast, the addition of 3 phr of TEM effectively reduced both the apparent density and pore size of the PBAs. The increase in resin viscosity owing to TEM could enhance bubble production stability, leading to the formation of more uniform and smaller pores. These results indicate that TEM is a highly efficient PBA that can be employed to decrease the weight and pore size of PU-PDMS hybrid foams.

• Journal of Powder Materials
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• v.21 no.4
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• pp.266-270
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• 2014

Metal foams have a cellular structure consisting of a solid metal containing a large volume fraction of pores. In particular, open, penetrating pores are necessary for industrial applications such as in high temperature filters and as a support for catalysts. In this study, Fe foam with above 90% porosity and 2 millimeter pore size was successfully fabricated by a slurry coating process and the pore properties were characterized. The Fe and $Fe_2O_3$ powder mixing ratios were controlled to produce Fe foams with different pore size and porosity. First, the slurry was prepared by uniform mixing with powders, distilled water and polyvinyl alcohol(PVA). After slurry coating on the polyurethane(PU) foam, the sample was dried at $80^{\circ}C$. The PVA and PU foams were then removed by heating at $700^{\circ}C$ for 3 hours. The debinded samples were subsequently sintered at $1250^{\circ}C$ with a holding time of 3 hours under hydrogen atmosphere. The three dimensional geometries of the obtained Fe foams with an open cell structure were investigated using X-ray micro CT(computed tomography) as well as the pore morphology, size and phase. The coated amount of slurry on the PU foam were increased with $Fe_2O_3$ mixing powder ratio but the shrinkage and porosity of Fe foams were decreased with $Fe_2O_3$ mixing powder ratio.