• 한국가스학회:학술대회논문집
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• 한국가스학회 2003년도 춘계학술발표회 논문집
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• pp.182-192
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• 2003

• 접착 및 계면
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• 제13권4호
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• pp.163-170
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• 2012

${\beta}$-cyclodextrin은 다른 분자를 포접하여 inclusion complex (포접착물)를 만드는 특성을 가지고 있기 때문에 의약품, 농약, 식품, 화장품, 산화방지제, 휘발방지제, 흡습방지제, 퇴색방지제, 유화제 등의 다양한 용도로 사용되고 있다. 이러한 장점에도 불구하고 ${\beta}$-cyclodextrin은 물이나 유기용매에 대한 용해도가 낮아 사용에 제약을 받아왔다. 본 연구에서는 이러한 문제를 해결하기 위해서 Bisphenol-A나 폴리우레탄(PU) 발포제인 cyclopropane에 대한 포접특성을 갖고 물이나 유기용매에 대한 용해도가 향상된 polyol type의 ${\beta}$-cyclodextrin 유도체를 합성한 후 그 특성을 고찰하였다. 연구결과 합성된 polyol을 사용해서 제조한 경질 PU foam은 기존의 polyol과 비교해서 더 우수한 열전도 특성과 압축강도를 나타내었다.

• 폴리머
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• 제25권4호
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• pp.528-535
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• 2001

본 연구에서는 polyol, MDI, 실리콘 유화제, 물을 기본 폴리우레탄 조성으로 설정하였으며, 경질 폴리우레탄 폼에 있어서 sitff-chain 요소인 에틸렌 글리콜의 첨가에 의하여 가교밀도가 증가하며, 이에 따른 셀의 크기, 발포 배율, cream time, gel time, take free time의 변화, 최종 자유 발포체 높이, 반응 온도, 단열도 변화를 관찰하였다. 발포제는 시클로펜탄을 사용하여 경질 물리우레탄을 발포하였으며, 상온, 상압에서 hand mixing 으로 5000 rpm, 4sec의 범위 안에서 혼합시킨 뒤에, 에틸렌 글리콜의 양을 변화시켜 200 ${\times}$ 200 ${\times}$ 200 mm 내의 나무 금형 안에서 발포 실험하였다. 이소시아네이트 인덱스를 고정시켰을 경우 에틸렌글리콜의 양이 증가함에 따라 셀의 크기는 약 5.1%와 열전도는 약 14%가 감소하였다.

• 폴리머
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• 제26권2호
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• pp.185-192
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• 2002

Polymeric 4,4'-diphenylmethane diisocyanate (PMDI), polyether polyol,1,4-butane diol, silicone surfactant와 발포제로 물을 사용하여 경질 폴리우레탄 폼 (PUF)을 제조하였다. PUF의 밀도는 0 php (parts per hundred polyol by weight)의 부탄다이올 양에 대하여 물의 양이 0.5~3.0 php로 증가함에 따라 173.7~41.7 kg/㎥로 감소하였다. PUF의 셀 크기는 10 php의 부탄다이올 양에 대하여 물의 양이 0.5~3.0 php로 증가함에 따라 115-258 $mu extrm{m}$로 증가하였다. PUF의 압축강도 측정 결과, 동일 밀도의 PUF에 대하여 압축강도는 물의 양이 증가함에 따라 증가하였다. 계면활성제가 PUF의 물성에 미치는 영향에 관한 연구에서, PUF의 셀 크기가 계면활성제 첨가량이 0~0.33 php로 증가함에 따라 360-146 $mu extrm{m}$로 감소하였으나 0.33 php 이상의 계면활성제 첨가량에 대해서는 더 이상의 셀 크기 변화가 관찰되지 않았다.

• Macromolecular Research
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• 제17권11호
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• pp.856-862
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• 2009

This study examined the effects of liquid and solid additives on the morphological, mechanical and thermal insulating properties of rigid polyurethane foams (PUFs). The PUFs synthesized with tetramethylsilane (TEMS) as a liquid-type additive showed a smaller average cell size and lower thermal conductivity than those with the aerosil 200 and clay 30B as solid-type additives. When TEMS was added, the average cell size of the PUF became more uniform and finer due to the reduced surface tension of the polymer solution, which increased the nucleation rate and number of bubbles produced and reduced cell size. The PUFs with TEMS showed the highest closed cell contents among the PUFs prepared using TEMS, aerosil 200 and clay 30B. This suggests that the insulation properties of PUF can be determined by both the size of the cell structure and the amount of closed cell contents in the system. The compression and flexural strengths of the PUF increased slightly when the aerosil 200, clay 30B and TEMS were added compared those of the neat PUF. The reaction profiles of the PUFs showed a similar gel and tack tree time with the reaction time among the PUFs synthesized with three different additives and neat PUF. This suggests that the nucleating additives used in this study do not affect the bubble growth of the chemical reaction, and the additives may act as nucleating agents during the formation of PUF. From the above results of the cell size, thermal conductivity, closed cell contents and reaction profile of the PUFs, liquid-type nucleating agent, such as TEMS, is more effective in decreasing the thermal conductivity of the PUF than solid-type nucleating agent, such as aerosil 200 and clay 30B.

• International Journal of Safety
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• 제4권1호
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• pp.14-17
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• 2005

Recycled polyol was obtained by glycolysis of MDI-based Polyurethane(PU) rigid foam. The chemical structure of the recycled pclyol was confirmed by GC(gas chromatography) and 1H-NMR. The recycled polyol throughout the glycolysis contained liquid polyol and methylenedianiline(MDA). MDA which could cause liver cancer is carcinogenic material. TWA(Time Weighted Average.) amount for MDA in MSDS(Material Safety Data Sheets) was confined less than 0.1 ppm. The melting temperature of MDA is $92^{\circ}C$, and boiling temperature is $398^{\circ}C$. During the gylcolysis most of MDA was dissolved in liquid polyol. The probability that MDA diffuses into the atmosphere is low but there could be an absorption of MDA into skin. Furthermore because MDA is amine compound, recycled polyol which contained MDA had a difficulty in reaction control of polyurethane. Therefore reduction of MDA amount was needed strongly. In this study the elimination of MDA were performed through deamination of the recycled polyol by glycidyl ether compounds. As glycolysis was proceeded, the amount of MDA was 9.8 wt % at early stage and increased up to 14.0 wt % after 8 hours reaction. It was found that 2-Ethylhexyl glycidyl ether which contains aliphatic moiety was very effective compound for eliminating the primary aromatic amine compound :md the optimal mole ratio of 2-ethylhexyl glycidyl ether to MAD was 3. The final polyol after deamination by 2-ethylhexyl glycidyl ether has an appropriate viscosity(less than 500 centi poise) for polyurethane reaction.

• KIEAE Journal
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• 제14권2호
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• pp.77-86
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• 2014

Plenty of efforts have been made in the traditional architecture of Korea, Hanok, to develop various elements such as restoration, the introduction of new design, and energy-saving while systemic setups on standard and evaluation of eco-friendly energy design of Hanok are lacking. If we evaluate energy performance based on current standards without reflecting unique features of Hanok on the system, Hanok will be included in the very low grade among the residential buildings being included in the approval system of eco-friendly architecture or the unique features will be modified and the burden of increased construction cost. Therefore, this study is to prepare the basic reference for the introductory evaluation system by evaluating the energy performance level of NEO-Hanok based on the current building energy rating system. The result for NEO-Hanok based on the building energy rating system, we propose the rating standard with scorecard elements of NEO-Hanok by considering the necessity of identity and standard for NEO-Hanok. As a result of infiltration test to check the tightness, it was measured as 10.81 times/h (50 ACH). As we switch from the main insulation for the wall from the glass wool 64k(0.035W/mk) to rigid polyurethane foam first class first unit (0.024W/mk), the result was slightly increased from the first demand quantity rating yield $249.8kWh/m^2{\cdot}yr$ to $235.0kWh/m^2{\cdot}yr$. Current certificate system is focused more on the heating load than the cooling load, it is disadvantageous for Hanok, which has less cooling energy consumption in summer. The rating result from the target building study is level 4.

• Steel and Composite Structures
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• 제27권6호
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• pp.717-725
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• 2018

One of the most important design criteria in military tunnels and armoured doors is to resist the blast loads with minimum structural weight. This can be achieved by using steel sandwich panels. In this paper, the nonlinear behaviour of steel sandwich panels, with different core materials: (1) Hollow (no core material); (2) Rigid Polyurethane Foam (RPF); and (3) Vulcanized Rubber (VR) under free air blast loads, was investigated using detailed 3D nonlinear finite element models in Ansys Autodyn. The accuracy of the finite element model proposed was verified using available experimental test data of a similar steel sandwich panel tested. The results show the developed finite element model can be reliably used to simulate the nonlinear behaviour of the steel sandwich panels under free air blast loads. The verified finite element model was used to examine the different parameters of the steel sandwich panel with different core materials. The result shows that the sandwich panel with RPF core material is more efficient than the VR sandwich panel followed by the Hollow sandwich panels. The average maximum displacement of RPF sandwich panel under different ranges of TNT charge (1 kg to 10 kg at a standoff distance of 1 m) is 49% and 53% less than the VR and Hollow sandwich panels, respectively. Detailed empirical design equations were provided to quantify the maximum deformation of the steel sandwich panels with different core materials and core thickness under a different range of blast loads. The developed equations can be used as a guide for engineer to design steel sandwich panels with RPF and VR core material under a different range of free air blast loads.

• Computers and Concrete
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• 제14권6호
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• pp.767-783
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• 2014

The use of composite materials to strengthen reinforced concrete (RC) structures against blast terror has great interests from engineering experts in structural retrofitting. The composite materials used in this study are rigid polyurethane foam (RPF) and aluminum foam (ALF). The aim of this study is to use the RPF and the ALF to strengthen the RC panels under blast load. The RC panel is considered to study the RPF and the ALF as structural retrofitting. Field blast test is conducted. The finite element analysis (FEA) is also used to model the RC panel under shock wave. The RC panel performance is studied based on detonating different TNT explosive charges. There is a good agreement between the results obtained by both the field blast test and the proposed numerical model. The composite materials improve the RC panel performance under the blast wave propagation.

• 한국산학기술학회논문지
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• 제16권4호
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• pp.2945-2950
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• 2015

경질 폴리우레탄 폼(RPUF) 제조에서의 단열성 향상을 위하여 사용되는 PFA (Perfluoroalkane)는 액상의 발포 기핵제로서 성능은 뛰어나지만 매우 고가일 뿐만 아니라 불소화합물로서 환경 유해성 물질이다. 따라서 이를 대체할 수 있는 고성능의 대체 기핵제 개발에 대한 많은 연구가 진행되고 있다. 본 연구에서는 이에 대하여 다중벽 탄소나노튜브(MWCNT)를 고상 기핵제로 사용하여 제조한 샘플에서의 셀 크기 및 단열 성능과 기계적 물성에 미치는 영향을 비교 연구하여 보고자 하였다. 셀의 평균크기는 $165.6{\mu}m$에서 $162.9{\mu}m$로 상대적으로 더 작아졌으며, 표준 편차 역시 각각 45.6 및 35.2로서 상대적으로 더 균일한 셀 크기 분포를 가진 것으로 나타났다. k-factor 값 역시 0.01763 및 $0.01745kcal/m.hr.^{\circ}C$의 값으로서 1.02%가 감소된 더 작은 값을 나타내었다. 또한 압축 응력 시험에서의 초기 모듈러스는 상대적으로 더 큰 값을 나타내었으나 압축항복 응력은 약 $0.030{\times}105Pa$로서 거의 같은 값을 나타내었다. 이러한 결과들로 부터 MWCNT는 매우 우수한 기핵제로 작용함을 알 수 있었고, 따라서 소량의 MWCNT를 기핵제로 사용하여 경제적이면서도 우수한 단열효과와 기계적 물성을 지닌 친환경적인 경질 폴리우레탄 폼을 제조할 수 있음을 알 수 있었다.