• 한국세라믹학회지
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• 제44권10호
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• pp.574-579
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• 2007

Porous $Al_2O_3$ ceramics were prepared by the gelcasting foams method (a slurry foaming process) with acrylamide monomer. The foaming and gelation behavior was investigated with the parameters such as the type and concentration of surfactant, solid loading of slurry, and the concentrations of initiator and catalyst. Density, porosity, microstructure, and strength of the green and sintered samples were characterized. Of the four kinds of surfactants tested, Triton X-114 showed the highest foaming ability for the solid loading of 55-30 vol%. The gelation condition giving the idle time off min was found to set the foamed structure without significant bubble enlargement and liquid lamella thinning. The green samples were fairly strong and machinable and showed maximum strength of 2.4 MPa in diametral compression. The sintered samples showed densities of 10-36% theoretical (i.e. porosity 90-64%) with a highly interconnected network of spherical pores with sizes ranging from 30 to $600{\mu}m$. The pore size and connectivity increased but the cell strut thickness decreased with decreasing the solid loading. Flexural strength of 37.8-1.7 MPa was obtained for the sintered samples.

• 상하수도학회지
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• 제24권4호
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• pp.369-376
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• 2010

The purpose of this study is to reprocess Waste-LCD(Liquid Crystal Display), to widely increase specific surface-area by foaming agent in the process of reprocessing and to use as a substrate of water treatment which is increased the ability of biological treatment, as well as to control non-point source pollutants produced by surface run off during rainfall with using this substrate, and to improve water quality of public watershed as developing substrate for water treatment to be able to purify second treated water which is exhausted at the wastewater treatment plant. The average removal efficiency of Waste-LCD that using the foaming technology was SS 71.2%, BOD 55.7%, COD 58.4%, T-N 29.5% and T-P was 50.3%. Almost Media, early stage showed low removal efficiency of SS and BOD. However, it became high when the microorganism adhered the Media. The variation of SS removal efficiency was high by inflow concentration of SS. The reason for the Media 4 showed high SS removal efficiency is that it has wide specific surface-area, and also it has a pore. All in all, it shows floating matter treatment ability not only inside but it also works outside of the substrate.

• 한국주조공학회지
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• 제28권2호
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• pp.79-84
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• 2008

Metal foam is one of the most interesting materials with various multi-functional properties such as light weight, energy absorption, high stiffness and damping capability. Among them, energy absorption property has keen interests in the field of automotives for passenger protection. Nowadays, researches about pore size and porosity control of the foam are increased to correspond them. However, though energy absorption properties are improved, these results are not cost-effective process. In present research, however, as a part of improving the energy absorption property of metallic foams, 606X aluminum alloy was used for cell wall material which has higher strength than pure aluminum. And its morphological features are characterized. As a results, porosity and pore size are uniformity distribution with increasing foaming temperature in the case of 6061 alloy foams. 6063 alloy foam specimens have opposite tendency because of the influence of alloying element and viscosity of the molten melt.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집C
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• pp.414-419
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• 2001

Microcellular foamed plastic is a foaming technology that is safer to the environment and has no significant deterioration of mechanical properties compared to the conventional foamed plastic. Currently, the development of the injection-molding machine for microcellular plastic (MCP) is nearing completion. Currently, researches on the mass production system for the MCP injection-molding machine are under progress. The purpose of this paper is to design the gas supply system suitable for microcellular foaming in the injection-molding machine. For the design process, Axiomatic Approach, a powerful tool for design, will be used.

• 소성∙가공
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• 제18권3호
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• pp.256-261
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• 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.

• Elastomers and Composites
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• 제49권4호
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• pp.323-329
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• 2014

MIF (Molded-In Foaming) 공법의 발포 거동에 적합한 고분자 기재를 선정하기 위해 SBC (K-resin KK38)와 SBS (KTR 101와 KTR 301)의 유변물성을 측정하였다. SBS의 유변물성 ($G^{\prime}$, $G^{{\prime}{\prime}}$, ${\eta}^*$)은 $155^{\circ}C$와 $170^{\circ}C$의 경우 시간에 따라 유변물성 값의 변화가 거의 없으나, $185^{\circ}C$와 $200^{\circ}C$의 경우에는 시간에 따라 증가하는 것을 볼 수 있었다. 특히, KTR 301의 유변물성 값이 시간에 따라 큰 폭으로 증가하였다. 시간에 따른 유변물성 상승의 정확한 원인을 확인하기 위해 $155^{\circ}C$와 $200^{\circ}C$에서 1800 s 이후의 KTR 301의 비선형 유변물성을 진폭에 대해 측정하였다. $155^{\circ}C$에서는 일반적인 수지와 같은 한 번의 박화(thinning)현상이 관찰되나 $200^{\circ}C$에서는 두 번의 박화현상이 관찰되었고 (Payne effect), 이는 고온에서 SBS가 겔화에 의한 경화가 일어난다고 볼 수 있다. 따라서 이러한 유변물성으로부터 MIF 공법에 요구되는 특성(발포 초기 낮은 점도와 발포 완료 이후 높은 점도)에 적합한 고분자 기재는 SBS KTR 301임을 확인할 수 있었다.

• 한국응용과학기술학회지
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• 제28권2호
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• pp.146-151
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• 2011

In this study, by using oleic acid and polypropylene glycol, good natured antifoaming agent for suitable electronics process under the alkaline conditions were synthesized. For the synthesized mono and diesters, acid value, hydroxyl value was measured, and identified by FT-IR and $^1H-NMR$ spectroscopy. Surface properties such as surface tension, critical micelle concentration(cmc) for diluted aqueous solution was measured, and tested the antifoaming properties according to the difference of alkyl chain length, various concentration, temperature and pH. The surface tension of synthesized antifoaming agent, PPMO(Polypropylene glycol monooleate) was 24.3 dyne/cm, PPDO(Polypropylene glycol dioleate) was 23.7 dyne/cm. By increasing of the alkyl chain length, surface tension was decreased slightly, and showed good antifoaming properties at 0.06 wt% concentration and $50^{\circ}C$, pH 11. These synthesized compounds are expected to apply as a suitable antifoaming agents in the semiconductor and the PCB(Printed Circuit Board) manufacturing process.

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

• Biotechnology and Bioprocess Engineering:BBE
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• 제8권3호
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• pp.167-172
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• 2003

Foam fractionation can be used to enrich a hydrophobic protein such as bromelain from an aerated dilute protein solution because the protein foams. On the other hand, a protein such as invertase, which is hydrophilic, is not likely to foam under similar aerated conditions. While a foam fractionation process may not be appropriate for recovering a hydrophilic protein alone, it is of interest to see how that non-foaming protein affects the foaming protein when the two are together in a mixture. The bromelain enrichment, activity and mass recovery were observed as a function of the solution pH in order to explore how invertase can affect the recovery of bromelain in a foam fractionation process.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2006년도 춘계학술발표대회 및 제10회 신소재 심포지엄 논문개요집
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• pp.7.2-7.2
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• 2006