• Korean Chemical Engineering Research
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• v.54 no.6
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• pp.830-837
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• 2016

In order to improve the compressive strength of graphite foams (GFms), mesophase pitch (MP) was stabilized in air atmosphere and then fluorinated at different conditions. The Fluorine/Carbon (F/C) in surface-chemical contents of fluorinated MP has range of 23.75%~61.48% according to the different fluorine partial pressure. The compressive strengths of GFms prepared from fluorinated MP were increased in proportion to the apparent densities. The compressive strength of the GFm produced from MP with 35.93% of F/C (%) showed maximum value in $2.93{\pm}0.06MPa$, which was increased up to 27.95% than that of the GFm prepared from un-fluorinated MP. This result was attributed that the interface bonding between of MPs due to fluorine functional groups with high surface energy helped to improve compressive strength of the GFm.

• Proceedings of the KAIS Fall Conference
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• 2005.05a
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• pp.277-278
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• 2005

미생물 고정화를 위하여 PU 폼을 세 가지 처리 방법으로 처리하였다. 플라즈마 처리, 플라즈마 유도 그라프팅, 플라즈마 유도 그라프팅 후 플라즈마로 재처리 방법을 사용하였다. 플라즈마 처리는 bacteria adhesion에 큰 효과를 주지 못하였고, 아크릴산의 플라즈마 유도 그라프팅은 adhesion을 세 배 이상 증가시켰다. Bacteria의 adhesion 성능 향상은 표면의 친수성을 증가시키고 새로운 groove나 cavity들을 형성시킴으로 가능하였다. 반면, 그라프팅 후 plasma re-treatment는 미생물 고정화를 크게 향상시키지 못하였다. SEM 관찰을 통하여 대부분의 E.coli.는 groove나 cavities라는 shear-free area에 서식함을 알 수 있었다. PU폼의 bacteria adhesion은 미생물과 고분자 표면 사이의 정전기적 인력이나 van der Waals 인 력에 의해 주로 영향을 받는다고 사료된다.

• Proceedings of the KSME Conference
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• 2001.11a
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• pp.38-43
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• 2001

The interfacial adhesive joining characteristics of the foams are very important for the structural integrity of sandwich structures. Peel strength is one of the best criteria for the interfacial characteristics of the sandwich structures and peel energy is most commonly used for the interfacial characteristics. The peel strength is the first peak force per unit width of bond line required to produce progressive separation by the wedge or other crack opening type action of two adherends where one or both undergo significant bending and the peel energy is the surface active energy per unit width of bond line. In this work, to investigate the strengthening effect of resin treatment on the interfacial surface of foam material, peel strength and peel energy of epoxy resin treated polyurethane foam core sandwich structures were obtained by the cleavage peel tests and compared with those of non surface treated polyurethane foam core sandwich structures.

• KSBB Journal
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• v.18 no.5
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• pp.412-417
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• 2003

We first investigated basic characteristics of reticulated polyurethane (PU) foams as microbial carriers. In general, the specific surface area of PU foams increases with respect to decreasing pore sizes. However, the number of microbes adhered on the unit surface of reticulated PU foams decreases with respect to decreasing pore sizes. Thus, as a result of totally considering all effects such as apparent density, hydrolysis rate, and adhesion, we can know that PU foams with 45 PPI is the most appropriate microbial carrier. In this study, we can also investigate the effect of various physico-chemical surface treatments on the adhesion of microbes on the surface of PU foams. We used a chitosan treatment, a PEI (Polyethylene Imine) treatment, a xanthane treatment and a plasma treatment. As a result of comparing all surface treatments, the plasma surface treatment was the best.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.224.1-224.1
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• 2010

본 연구에서는 천연가스 수증기 개질반응에 니켈 촉매가 코팅된 금속 구조체 촉매를 적용하여 수소를 생산하였다. 금속구조체 촉매는 기존 펠릿 촉매가 충진 된 촉매반응기에 비해 열 및 물질 전달 특성이 우수하여 이를 여러 개질반응에 적용하고자하는 연구가 수행되어 왔다. 하지만, 기존 금속구조체 촉매의 개발에 있어 촉매와 금속 지지체간의 안정한 결합을 통한 열안정성 확보에 대한 문제는 여전히 해결과제로 남아 있다. 따라서, 본 연구에서는 니켈 촉매를 금속 지지체에 안정하게 부착하기 위한 금속 지지체 표면 처리 방법을 개발하였으며 금속 구조체의 형상에 상관없이 균일한 표면처리가 가능하였다. 개발된 표면 처리방법을 적용한 금속 구조체 촉매는 촉매와 금속지지체간의 결합력 향상으로 인해 120시간 이상 안정한 반응활성을 보였다. 또한, 빠른 공간속도에서도 펠릿촉매와 표면처리를 적용하지 않은 금속 구조체 촉매에 비해 높은 촉매 활성을 보였다. 뿐만 아니라, 본 연구에서 개발된 표면처리를 모노리스와 폼을 비롯한 다양한 형상의 금속구조체 촉매에 적용하여 기하학적 표면 특성에 따른 촉매의 활성 차이를 살펴보았다. 겉보기 표면적이 넓은 금속구조체일 수록 촉매의 고분산 코팅에 유리하여 높은 활성을 보였다.

• Journal of Adhesion and Interface
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• v.8 no.3
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• pp.1-8
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• 2007

An atmospheric plasma pre-treatment method was applied to polyurethane foam to improve its contact angle and adhesion. In order to investigate the optimum reaction condition of plasma treatment, type of reaction gas (nitrogen, argon, oxygen, air), rate of gas flow (30~150 mL/min), and reaction time (0~30 sec) were examined in a plate plasma reactor. Also, the effects were compared to those of a conventional vacuum plasma pre-treatment system. The result of the surface modification with respect to the treatment procedure was characterized by using SEM and ATR-FTIR. Due to a decrease of the contact angle of polyurethane foam, the greatest adhesion strength was achieved at a flow rate of 100 mL/min and at a reaction time of 10s for N2 gas. Consequently, the atmospheric plasma treatment reduced the contact angle of the polyurethane foam and also resulted in the improvement of the peel strength.

• Korean Chemical Engineering Research
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• v.53 no.4
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• pp.425-430
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• 2015

ZSM-5 crystals grew by hydrothermal synthesis method on the surface of foam type porous silicon carbide ceramics which fabricated by polymer replica method. Oxide layer was developed on the surface of the porous silicon carbide ceramics to induce growth of ZSM-5 from the surface. In this study, hydrothermal synthesis was carried out for 7 h at $150^{\circ}C$ using TEOS, $Al(NO_3){\cdot}9H_2O$ and TPAOH as raw materials in the presence of the porous silicon carbide ceramics. X-ray Powder Diffraction (XRD) and Scanning Electron Microscope (SEM) analyses were confirmed $1{\sim}3{\mu}m$ sized ZSM-5 crystals have grown on the surface of porous silicon carbide ceramics. BET data shows that small pores about $10{\AA}$ size drastically enhanced and surface area increased from $0.83m^2/g$ to $30.75m^2/g$ after ZSM-5 synthesis on the surface of foam type porous silicon carbide ceramics.

• Journal of Conservation Science
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• v.31 no.4
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• pp.351-360
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• 2015

This is the result of the study on the temporary fortifier using sublimation type Consolidate is Cyclododecane to prepare plan for reinforcement of the surface part that can be damaged during the dismantling of stone cultural heritages. To supplement the disadvantages of the existing reinforcement methods using intumescent urethane foam, Cyclododecane was diluted in solvent to reinforce the surface and inside desquamation, and after dismantling the framework, it sublimated by imposing heat of about $60^{\circ}C$. Such method can guarantee the strength needed for reinforcement of the damaged surface with outstanding reversibility of Cyclododecane being entirely sublimated. But, it shows big difference of effect according to the solvent, so it shall be diluted in petroleum ether or heated in a double boiler. Therefore, considering the working conditions at the site, it seems the most appropriate to use petroleum ether double boiler heating method for injection and filling of the desquamation part and temporary reinforcement processing with Cyclododecane diluted in petroleum ether for surface spraying.

• Journal of the Korean Wood Science and Technology
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• v.42 no.6
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• pp.714-722
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• 2014

In the previous study, a variety of wood-based panels was thermally decomposed to manufacture carbonized boards that had been proved to be high abilities of insect and fungi repellence, corrosion and fire resistant, electronic shielding, and formaldehyde adsorption as well as sound absorption performance. Based on the previous study, carbonized medium density fiberboard (c-MDF) was chosen to improve sound absorption performance by holing and sanding process. Three different types of holes (cross shape, square shape, and line) with three different sanding thickness (1, 2, and 3 mm) were applied on c-MDF and then determined sound absorption coefficient (SAC). The control c-MDF without holes had 14% of SAC, however, those c-MDFs with holes had 16.01% (square shape), 15.68% (cross shape), and 14.25% (line) of SAC. Therefore, making holes on the c-MDF did not significantly affect on the SAC. As the degree of sanding increased, the SAC of c-MDF increased approximately 65% on sanding treated c-MDFs (21.5, 21.83, and 19.37%, respectively) compared to the control c-MDF (13%). Based on these results, composite sound absorbing panel was developed with c-MDF and MDF (11 mm). The noise reduction coefficient of composite sound absorbing panel was 0.45 which was high enough to certify as sound absorbing material.

• Applied Chemistry for Engineering
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• v.34 no.1
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• pp.30-35
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• 2023

The glass bead surface was coated using a TiO₂ sol, after which dry-treated (TB) and calcined (TBc) samples were prepared. Photocatalytic degradation of methylene blue and toluene, as well as characterization of the TiO₂ thin films, were carried out. The TiO₂ thin film of the TB sample had the same shape as the sponge foam, according to FE-SEM, XPS, and FTIR analyses, and contained both amorphous and crystalline TiO₂. On the other hand, crystalline TiO₂ was mainly present in the TiO₂ thin film of the TBc sample, and needle-shaped particles and tiny ones were mixed. The adsorption capacity for methylene blue and the degradation rate of the TBc sample were less than 10 % compared with those of the TB sample, and the adsorption capacity and degradation rate of the TBc sample decreased similarly as the amount of TiO₂ coating increased. The amount of toluene adsorption for the TBc sample (46 mg/g) was smaller than that of the TB sample with the same coating amount, but the degradation rate was similar. In the case of the TB sample, the degradation rate for toluene decreased less than the adsorption capacity as the amount of TiO₂ coating increased. This result is considered to be because, in the non-calcined TB sample, the active site reduction of the crystalline particles occurred less and the specific surface area of the amorphous texture decreased as the amount of TiO₂ coating increased.