• 한국생활과학회지
• /
• 제24권2호
• /
• pp.285-295
• /
• 2015

To identify optimized thermal properties of mold brassiere cup for improved thermal comfort during summer, we compared the thermal resistance and the water vapor permeability of Polyurethane (PU) foam, 3D spacer fabric and the two combined materials of the PU foam and the 3D spacer fabric. Four experimental mold brassieres were made of the materials for wearing test. Six women in their twenties evaluated the wearing sensation in the hot and humid environment. The changes in microclimate temperature and humidity while wearing test brassiere cups were measured. Results indicate that thermal resistance increased as more PU foam were combined, while the water vapor permeability was higher as the content of the 3D spacer fabric increased at thickness of 18mm and over. However, in the wear test, the PU foam brassiere was the most preferred in all ambient conditions due to its soft, flexible and smooth texture, despite its high thermal resistance and low water vapor permeability. This indicates that the textures of mold foams are more dominant properties than thermal properties for mold foams in determining the wear comfort of mold brassieres.

• 한국화재소방학회논문지
• /
• 제20권4호
• /
• pp.110-115
• /
• 2006

폴리우레탄에 인계 화합물을 첨가하여 폴리우레탄폼을 제조하였으며, 인계 화합물이 제조된 폴리우레탄폼의 기계적 물성과 난연성에 미치는 영향에 대하여 고찰하였다. 폴리우레탄과 인계 난연제인 Tri(chloroisopropyl) phosphate(TCPP), Triethyl phosphate(TEP), Trimethyl phosphate(TMP) 각각을 약 $90^{\circ}C$에서 혼합시켜 혼합물로부터 제조된 경질 폴리우레탄폼에 대한 여러 실험을 통하여 기계적 물성뿐만 아니라 난연 효과도 상당히 향상됨을 확인하였다. Cone calorimeter를 이용하여 열방출율(heat release rate, HRR)을 측정하여 난연 첨가제의 함량에 따른 재료별 난연 특성을 평가하였다. 그리고 Scanning Electron Microscope(SEM)을 사용하여 난연제를 첨가하여 만든 폴리우레탄폼의 morphology를 관찰한 결과 순수한 폼과 마찬가지로 매우 균일한 형태의 cell 분포를 가짐을 확인하였다.

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 2008년도 추계학술대회 논문집
• /
• pp.106-109
• /
• 2008

Polyurethane has been one of the most important materials for automobile elastic parts such as bumper, head rest, instrument panel and so on since it covers very wide range of mechanical characteristics with low production costs. The process variables such as formulation of ingredients and mold temperature, mixing speed, etc. can affect the quality of produced polyurethane foams so that process conditions should be determined appropriately. In this study, foaming behaviors of semi-rigid polyurethane were investigated by conducting cup foam tests with 2 major process variables such as environmental temperature and blowing agent content.

• 소성∙가공
• /
• 제18권3호
• /
• pp.256-261
• /
• 2009

Polyurethane has been one of the most important materials for automobile elastic parts such as bumper, head rest, instrument panel and so on since it covers very wide range of mechanical characteristics with low production costs. The processing variables such as formulation of ingredients and mold temperature, mixing speed, etc. can affect the quality of produced polyurethane foams so that process conditions should be determined appropriately. In this study, foaming behaviors of semi-rigid polyurethane were investigated by conducting cup foam tests with two major processing variables such as environmental temperature and blowing agent content. In addition, it was verified that processing conditions of real practice can be determined effectively by considering foaming characteristics obtained by the cup foam tests.

• KSBB Journal
• /
• 제7권3호
• /
• pp.172-178
• /
• 1992

담체로 사용된 polyurethane foam은 Rizopus chinensis의 균사가 부착하여 안정하게 증식할 수 있게 하였다. 고정화를 위해 사용된 네 종류의 polyurethane foam중 GP-160이 고정하ㅗ 매체로 우수한 성질을 보였고, 입자의 크기는 7-8mm가 적당하였다. Rizopus chinensis의 현탁 배양과 polyurethane foam에서의 고정화 배양을 비교할 때, 전체 리파아제의 활성도는 큰 변화가 없었지만, 고정화 배양의 경우 extracellualar lipase의 생성을 억제하여 intracellular lipase의 활성도를 현탁 배양의 경우보다 약 2배가량 높일 수가 있었다. 고정화 세포의 열안정성을 조사하기 위하여 35~$50^{\circ}C$사이에서 열에의한 비활성화 에너지값을 구해본 결과, 그 값이 28.7kcal/mol로서 본 연구에서 제조된 고정화 세포의 생촉매가 배교적 좋은 열안정성을 갖고 있다.

• International Journal of Advanced Culture Technology
• /
• 제3권1호
• /
• pp.21-30
• /
• 2015

Ceramic foams are prepared as positive images corresponding to a plastic foam structure which exhibits high porosities (85-90%). This structure makes the ceramic foams attractive as a catalyst in a dry reforming process, because it could reduce a high pressure drop problem. This problem causes low mass and heat transfers in the process. Furthermore, the reactants would shortly contact to catalyst surface, thus low conversion could occur. Therefore, this research addressed the preparation of dry reforming catalysts using a sol-gel catalyst preparation via a polymeric sponge method. The specific objectives of this work are to investigate the effects of polymer foam structure (such as porosity, pore sizes, and cell characteristics) on a catalyst performance and to observe the influences of catalyst preparation parameters to yield a replica of the original structure of polymeric foam. To accomplish these objectives industrial waste foams, polyurethane (PU) and polyvinyl alcohol (PVA) foams, were used as a polymeric template. Results indicated that the porosity of the polyurethane and polyvinyl alcohol foams were about 99% and 97%. Their average cell sizes were approximate 200 and 50 micrometres, respectively. The cell characteristics of polymer foams exhibited the character of a high permeability material that can be able to dip with ceramic slurry, which was synthesized with various viscosities, during a catalyst preparation step. Next, morphology of ceramic foams was explored using scanning electron microscopy (SEM), and catalyst properties, such as; temperature profile of catalyst reduction, metal dispersion, and surface area, were also characterized by $H_2-TPR$ and $H_2-TPD$ techniques, and BET, respectively. From the results, it was found that metal-particle dispersion was relatively high about 5.89%, whereas the surface area of ceramic foam catalysts was $64.52m^2/g$. Finally, the catalytic behaviour toward hydrogen production through the dry reforming of methane using a fixed-bed reactor was evaluated under certain operating conditions. The approaches from this research provide a direction for further improvement of marketable environmental friendly catalyst production.

• 한국음향학회지
• /
• 제30권1호
• /
• pp.17-21
• /
• 2011

수중에서 음향신호를 측정할 때에 청음기 주위에서의 유동에 의해 발생하는 초저주파 대역 자체소음을 저감시키기 위해 청음기 주위에 다공성 발포재를 씌우는 기법의 효과를 해상 실험을 통해 고찰하였다. 두께가 다른 10 ppi 폴리우레탄 발포재를 이용하여 실험한 결과, 2-10 Hz 대역에서 발포재의 두께가 1 cm일 때에는 최대 20 dB 그리고 발포재의 두께가 3 cm인 경우에는 최대 28 dB의 자체소음 저감 효과가 있음을 확인하였다.

• 한국가스학회지
• /
• 제16권5호
• /
• pp.66-75
• /
• 2012

본 연구에서는 석유계 폴리올을 대체하기 위하여 식물성 천연유인 피마자유를 개질한 천연유 기반 폴리올(Castor Oil based Polyol, COP)을 사용하여 폴리우레탄 폼을 합성하였다. 접촉각과 표면장력실험을 통해 계면활성제에 따른 석유계 폴리올과 COP와의 상용성을 측정하였다. 최적의 COP 함량과 계면활성제(surfactant)를 찾기 위해 COP 함량을 0 wt%에서 80 wt%까지 변화시키고, 계면활성제 L-580K, DC-5950, BF-2470를 사용하여 폴리우레탄 폼을 합성한 결과 COP의 함량이 30wt%이고 계면활성제로 BF-2470을 사용하였을 때 가장 우수한 기계적 물성을 나타내었다.

• 한국가스학회지
• /
• 제9권1호
• /
• pp.16-20
• /
• 2005

LNG저장탱크용 경질 폴리우레탄 폼의 발포에 많이 사용되어온 것은 CFC-11이었으며 현재 사용되고 있는 것은 HCFC-l4lb이다. 하지만 CFC-11과 이의 대안으로 사용되고 있는 HCFC-l4lb는 성층권에 존재하는 오존층(ozone layer)을 파괴하기 때문에, 선진국의 경우 CFC-11은 1996년부터 사용이 금지되어 왔으며 HCFC-141b도 2005년부터 사용이 금지될 예정이다. 이러한 국제적 제약으로 인해 이들 발포제를 대체할 차세대 발포제와 이를 이용한 폴리우레탄 폼에 대한 연구가 활발히 진행되고 있다. 본 논문에서는 HFC계 발포제를 사용하여 합성한 경질폴리우레탄 폼의 물리적, 기계적 특성을 측정하였으며 이 결과를 HCFC-l4lb를 사용하여 합성한 경질폴리우레탄 폼의 특성과 비교하였으며 이로부터 LNG저장탱크용 단열재에 있어서 HFC계 발포제의 HCFC-l4lb대체가능성에 대하여 검토하였다.

• Elastomers and Composites
• /
• 제58권1호
• /
• pp.32-43
• /
• 2023

The worldwide use of polyurethane foam products generates large amounts of waste, which in turn has detrimental effects on the surroundings. Hence, finding an economical and environmentally friendly way to dispose of or recycle foam waste is an utmost priority for researchers to overcome this problem. In that sense, the glycolysis of waste flexible polyurethane foam (WFPF) from automotive seat cushions using different industrial-grade glycols and potassium hydroxide as a catalyst to produce recovered polyol was investigated. The effect of different molecular weight polyols, catalyst concentration, and material ratio (PU foam: Glycols) on the reaction conversion and viscosity of the recovered polyols was determined. The obtained recovered polyols are obtained as single or split-phase reaction products. Besides, the foaming characteristics and physical properties such as cell morphology, thermal stability, and compressive stress-strain nature of the regenerated flexible foams based on the recovered polyols were discussed. It was observed that the regenerated flexible foams displayed good seating comfort properties as a function of hardness, sag factor, and hysteresis loss compared to the reference virgin foam. With the growing demand for a sustainable and circular economy, a global valorization of glycolysis products from polyurethane scraps can be realized by transforming them into profitable substances.