• 한국산학기술학회논문지
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• 제13권6호
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• pp.2846-2851
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• 2012

미세하게 분쇄된 폐타이어 분말(GTR)과 미발포 $Expancel^{(R)}$ 분말이 경질 폴리우레탄 발포체(PUF)의 열전도 특성에 미치는 영향을 연구하였다. 마이크론 크기로 분쇄된 GTR과 $100^{\circ}C$ 이상의 온도 영역에서 약 40배 부피로 팽창 가능한 $Expancel^{(R)}$ 미세분말을 사용하였고 이들이 경질 PUF 생성 시의 발포 기핵제 역할에 의한 기포크기 감소효과 및 이로 인한 PUF의 열전도특성 개선 효과를 집중적으로 살펴보았다. 연구의 결과로서, GTR이 충전된 PUF 샘플들의 열전도도는 GTR 함량이 증가함에 따라 선형적으로 증가하는 현상을 나타내는 반면, $Expancel^{(R)}$이 도입된 샘플들은 농도에 따라 약간 감소하는 특성을 보여 주었다. 이러한 결과로부터 GTR은 PUF 생성에서 증량제의 역할이 상대적으로 우세하여 단열 특성에 기여하지 못하는 반면, $Expancel^{(R)}$은 분말의 표면극성으로 인한 발포 기핵 작용에 의하여 셀 크기를 감소시킴으로서 단열효과에 기여할 수 있는 것으로 생각되었다.

• Macromolecular Research
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• 제15권7호
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• pp.676-681
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• 2007

A process designed to synthesize rigid polyurethane foam (PUF) with insulative properties via the modulation of PUF cell size via the addition of clay and the application of ultrasound was assessed. The blowing agents utilized in this study include water, cyclopentane, and HFC-365mfc, all of which are known to be environmentally-friendly blowing agents. The rigid PUFs were prepared from polymeric 4,4'-diphenylmethane diisocyanate (PMDI) and polyether polyol with a density of $50kg/m^3$. In addition, rigid PUFs/clay nanocomposites were synthesized with clay modified by PMDI with and without the application of ultrasound. The PUF generated using water as a blowing agent evidenced the highest tensile strength. The tensile strength of the PUF/nanocomposites was higher than that of the neat PUF and the strength was even higher with the application of ultrasound. The cell size of the PUF/clay nanocomposites was less than that of the neat PUF, regardless of the type of blowing agent utilized. It appears that the higher tensile strength and lower cell size of the PUF/clay nanocomposites may be attributable to the uniform dispersion of the clay via ultrasonic agitation. The thermal conductivity of the PUF/clay nanocomposites generated with HCFC-141b evidenced the lowest value when PUF/clay nanocomposites were compared with other blowing agents, including HFC-365mfc, cyclopentane, and water. Ultrasound has also proven effective with regard to the reduction of the thermal conductivity of the PUF/clay nanocomposites with any of the blowing agents employed in this study. It has also been suggested that the uniformly dispersed clay particles in the PUF matrix function as diffusion barriers, which prevent the amelioration of the thermal insulation property.

• Macromolecular Research
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• 제11권6호
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• pp.488-494
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• 2003

We have fabricated gelatin-immobilized polyurethane foams (PUFG) by dipping polyurethane foam (PUF) in an aqueous solution containing gelatin and by subsequent reaction with glutaraldehyde after freeze-drying. Gelatin aqueous solutions of different concentrations were used as the dipping solutions to control the amount of immobilized gelatin. The average pore size of PUF decreased with an increase in gelatin concentration. It was found from the hepatocyte adhesion experiment that the amount of hepatocytes seeded on PUFG1, prepared by using a 1% aqueous gelatin solution, was higher than that on other PUFGs. The hepatocytes inoculated in PUFG1, were slightly aggregated as the incubation time increased. The cells inoculated in PUFG1 showed higher ammonia removal ability than those monolayer-cultured on a gelatin-immobilized polystyrene dish (PSG) after 1 and 4 days of incubation time. The inoculated cells exhibited higher albumin secretion relative to monolayer-cultured hepatocytes on PSG. Albumin secretion by hepatocytes seeded on PUFG1 was increased by the presence of serum and was further increased by both the presence of serum and cytokines. The results obtained from a 3-(3,4-dimethylthiazol-2yl)-2,5-diphenyltetrazolium bromide (MTT) assay indicated that PUFG can provide a better microenvironment for hepatocyte culture along with nutrition and metabolite transfer through the high porosity of PUF.

• Elastomers and Composites
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• 제50권4호
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• pp.297-303
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• 2015

Ammonium polyphosphate-polyurethane foam composite (APP-PUF) was prepared from poly(adipate)diol/ammonium polyphosphate composite (f = 2), polyether polyol (f = 4.6), and PMDI (f = 2.5). As a blowing agent, $H_2O$ was used at various concentrations. The thermal decomposition behavior, morphology, closed-cell content, and density of APP-PUF were characterized. At the $H_2O$ concentrations lower than 3.5 php, the cell size of pure polyurethane foams (PUF) and APP-PUFs were close each other. As the $H_2O$ concentration became greater than 5.0 php, the cell size of the PUFs greatly increased compared to that of APP-PUFs. Addition of 1.5~1.9 wt% ammonium polyphosphate to the PUFs greatly enhanced the thermal stability of the PUFs, so 50 wt% residual temperature of APP-PUFs increased to $380{\sim}488^{\circ}C$, which were $30{\sim}70^{\circ}C$ higher than those of the PUFs. Thermal stability of the PUFs and APP-PUFs increased with $H_2O$ content and then decreased once $H_2O$ content exceeded 5 php.

• 공업화학
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• 제19권4호
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• pp.427-431
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• 2008

해수 하에서 경시변화에 따른 경질 폴리우레탄 폼의 물성변화를 알아보기 위해 이소시아네이트 인덱스를 변화시키며 경질 폴리우레탄 폼(PUF)을 합성하였다. 해수 하에서 이소시아네이트의 인덱스가 90, 100, 130, 150으로 증가함에 따라 PUF의 인장강도는 각각 10%, 3%, 7%, 4%씩 감소하였고, 압축강도는 각각 7%, 6%, 5%, 4%씩 감소하였다. PUF의 물성저하를 규명하기 위해 PUF의 기공을 확인한 결과 기공의 변화는 없었다. 해수 하에서 PUF의 유리전이온도($T_g$), 인장 모듈러스는 증가하였는데 적외선 스펙트럼 분석결과 우레아, 알로파네이트, 바이우렛이 증가하는 것을 알 수 있었다. 해수 하에서 PUF는 가교도 증가하고 이로 인해 폼이 brittle하게 형성되어 $T_g$의 증가에도 불구하고 기계적 물성이 저하된 것으로 사료된다. 해수 하에서 PUF의 물성변화를 고찰하기 위해 만능시험기, 시차 주사 열량계, 주사 전자 현미경, 적외선 분광계를 이용하였다.

• 한국산업융합학회 논문집
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• 제10권2호
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• pp.73-80
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• 2007

The preparation of oil absorbent using waste polyurethane was studied. And the effects of shape, size, and contents of waste polyurethane foam was investigated. The waste foam was treated in shape of powder, cube and bar type generated from rigid sandwich panel process. The tests for flexural strength, combustibility, and water absorptivity were carried out to investigate the mechanical and physical properties of the recycled foams. And the cell microstructure was evaluated through Scanning Electron Micrograph. The recycled foam containing powder-shaped underfilled and showed poor properties that was generated through reactivity of the resins and increasing of slurry viscosity. For the recycled foam with the cube and bar-shaped, the underfilling was caused by interference between the waste PUFs and increasing surface areas of PUF. Low cell density, non-uniformity of cell shape and size, and low adhesion of the boundary surface (new/recycled) was showed as a result of the poor properties. Considering underfilling and the properties of PUF (new/recycled), maximum recycle contents were less than 20 wt% for the powder and above 40 wt% for the cube and bar.

• Composites Research
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• 제34권1호
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• pp.16-22
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• 2021

폴리우레탄폼(PUF)은 연질, 반경질, 경질 형태로 제작이 가능하여 산업적으로 다양한 분야에서 활용되고 있다. 그 중에서도 경질 폴리우레탄폼은 우수한 기계적 특성과 낮은 열전도도를 가지고 있어, 건축물의 단열재와 천연가스 운수송 분야에서 보냉재로 사용되고 있다. 해당 분야에서는 기계적 강도는 높이고 열전도도는 낮추고자 하는 기술적 수요가 꾸준히 요구되고 있다. 본 연구에서는 경질 폴리우레탄폼을 제작하고, 교반기의 임펠러 형태(Propeller, Dispersed turbine)에 따른 폼의 미세구조와 물성 변화를 연구하였다. FE-SEM 이미지 및 Micro-CT 분석을 통해 Dispersed turbine으로 제조한 폼의 평균 기공 크기가 Propeller로 제조한 기공보다 21.5% 작은 것을 확인하였다. 압축 강도는 작은 기공을 가진 폼에서 15.4% 향상되었고, 열전도도는 3.1% 감소하였다. 이러한 결과는 PUF 복합재 제조에 활용될 수 있다.

• Journal of Microbiology and Biotechnology
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• 제13권1호
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• pp.29-34
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• 2003

A Pseudomonas sp. strain NGK1 (NCIM 5120) capable of utilizing salicylate was immobilized in alginate and polyurethane foam (PUF). The degradation rate of salicylate by freely suspended cells was compared with the degradation rate by immobilized cells. In an initial 20 and 40 mM salicylate, free cells ($2{\times}10^{11}\;cfu\;ml^{-1}$) degraded to 16 and 14 mM, alginate-entrapped cells degraded to 18 and 26 mM, and PUF-entrapped cells degraded to 20 and 32 mM salicylate, respectively, in batch cultures. The alginate-and PUF-entrapped cells were used in repeated batch and continuous culture systems. The efficiency of both the immobilized systems f3r the degradation of salicylate was compared. It has been observed that the PUF-entrapped cells could be reused for more than 20 cycles whereas alginate-entrapped cells could be reused for a maximum of only 12 cycles, after which a decrease in degradation rat was observed with the initial 20 and 40 mM salicylate. The continuous degradation of sallcylate by freely suspended cells showed a negligible degradation rate of salicylate when compared with immobilized cells. With the immobilized cells in both alginate and polyurethane foam, the degradation rate increased with an increase in the dilution rate up to $2\;h^{-1}$ for 20 mM, and $1.5\;h^{-1}$ for 40 mM salicylate. The results revealed that PUF-entrapped cells were more efficient for the degradation of salicylate than alginate-entrapped cells and freely suspended cells.

• 한국대기환경학회지
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• 제26권1호
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• pp.77-84
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• 2010

The diffusion and partition coefficients of polyurethane foam (PUF) are estimated using a microbalance experiment and small chamber test. The microbalance is used to measure sorption/desorption kinetics and equilibrium data. When the diffusion condition is controlled in the chamber of the sample, interactions between volatile organic compounds (VOCs) and PUF can lead to the estimation of a relatively homogenous rate of mass transfer in the interiors and surfaces of PUF. The estimates of the material/air partition coefficient (K) and the material-phase diffusion coefficient (D) are shown to be independent of the concentrations of VOCs. This approach, if applied to a diffusion-controlled or physically-based model, can facilitate more precise prediction of their source/sink behavior. Although further research and more rigorous validation is needed, an emission model applied with the diffusion and partition coefficients from this research holds promise for the improvement of reliability in predicting the behavior of VOCs emitted from porous building materials by D and K.

• 대한조선학회논문집
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• 제56권4호
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• pp.291-297
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• 2019

Polyurethane foam is the most efficient, high-performance insulation material, used for liquefied natural gas carrier (LNGC) insulation. Because LNGC is exposed to sloshing impact load due to ship motion of 6 degrees of freedom, polyurethane foam should be sufficient dynamic properties. The dynamic properties of these polyurethane foam depends on temperature and density. Therefore, this study investigates the dynamic response of polyurethane foam for various temperature($25^{\circ}C$, $-70^{\circ}C$, $-163^{\circ}C$) and density($90kg/m^3$, $113kg/m^3$, $134kg/m^3$, $150kg/m^3$) under drop impact test with impact energy of 20J, 50J, and 80J. For dynamic response was evaluated in terms of peak force, peak displacement, absorb energy, and the mechanical property with minimized density effects. The results show the effect of temperature and density on the polyurethane foam material for the dynamic response.