• Korean Chemical Engineering Research
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• v.43 no.5
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• pp.579-587
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• 2005

Phase separations of Poly(4-vinylphenol)(PVPh)/acetone and PVPh/methyl ethyl ketone solutions were measured using the thermal optical analysis (TOA) method. The phase separations of these system showed the behaviors of LCST-type (lower critical solution temperature). The measured cloud temperatures were lowered with increasing molecular weight of PVPh, and cloud temperatures of PVPh/MEK solutions shifted to higher temperature regions, compared to the PVPh/acetone solutions. Phase equilibria of PVPh/ketone solutions were described with taking account of self-associations of PVPh and cross-associations between PVPh and solvent, by using the PC-SAFT equation of state. PC-SAFT EoS parameters of PVPh and cross-association parameters were determined by simultaneously fitting liquid density data of PVPh and VLE data of the PVPh/acetone system. The estimated parameters of PVPh and cross-association parameters were utilized to calculations of the binodal and spinodal curves, and the calculated binodal curves were in good agreements with the experimental cloud temperatures.

• Korean Chemical Engineering Research
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• v.56 no.1
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• pp.29-41
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• 2018

Separating a mixture having an azeotrope or low relative volatility with single distillation column is difficult. Separating water-acetic acid mixture and water-ethanol mixture with a distillation column consumes a lot of energy. Pervaporation membrane can be used to separate the mixture in the concentration region where separation is difficult with distillation. We simulated a distillation-membrane hybrid process where membrane is located on the head of the distillation column for efficient separation of water-acetic acid and water-ethanol mixture. Permeability data were obtained from experiments and literature. We formulated an optimization problem for the process with total annual cost (TAC) as an objective function and major design variables as optimization variables. Major optimization variable affecting TAC of the hybrid process was shown to be distillate concentration. We also suggested a simplified optimization procedure to get a close-to-optimal solution.

• Polymer Science and Technology
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• v.15 no.3
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• pp.327-333
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• 2004

블록공중합체를 한 블록에 대해서만 선택적인 용매에 용해시키면 자발적인 상분리에 의하여 크기가 50 nm에서 200 nm 정도인 마이셀 구조로 자기 조립되며, 그 크기와 형태는 벌크상에서와 마찬가지로 블록공중합체의 분자량, 각 블록의 부피비, 각 블록간과 블록과 용매간의 Flory-Huggins 상호작용계수 ($\chi$)등에 의해서 결정된다. (중략)

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.61-61
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• 2010

니켈 니켈 와이어를 증류수 및 에탄올 등의 유기용매 중에서 펄스파워 기술을 이용하여 전기적으로 폭발 시켰다. 폭발에 의하여 생성된 입자들은 직경이 수 마이크로미터 에서 수 십 나노미터에 이르는 넓은 입도분포를 보였다. 본 연구에서는 원심분리기술을 이용하여 입자의 크기별로 분리 회수가 가능함을 증명하였다. 또한 유기용매 중에서 제조된 니켈분말에 탄소가 포함되어 있으며, 열처리를 통하여 제거가 가능함을 실험을 통하여 밝혔다.

• Proceedings of the Membrane Society of Korea Conference
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• 1997.10a
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• pp.79-80
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• 1997

1. 서론 : 열유도 상분리법(TIPS)은 일반적으로 상온에서 적정용매가 없는 고분자 소재를 아용하여 고분자-희석제 2성분계의 혼합물을 적절한 냉각 속도로 상분리 온도 이하로 급냉시켜 연속상과 분산상의 상분리를 일으킨 후 matrix전체에 다공성을 부여하여 분리막을 제조하는 공정이다. 폴리올레핀계 고분자를 중심으로 나일론11. 폴리카보네이트, PVC, ABS 수지 등을 소재로 plasmapheresis, 인공심폐기, breathing wear 등의 용도로 많이 응용되어 왔으며 현재 한외여과나 정밀여과 등 수투과 공정 및 battery separator 등으로의 응용이 활발하게 연구되고 있다. TIPS공정에 의해 제조된 고분자 분리막은 기존의 분리막에 비해 내열성 및 내약품성이 우수하며 여러 가지 다양한 변수로 부터 막의 미세구조를 조절할 수 있어 기공의 크기 및 모양이 조절 가능하다. 본 연구에서는 TIPS 공정을 이용한 고분자 분리막의 제조시 take-up speed와 air gap 등을 변화시켜 이에 따른 영향을 조사하였고 또한 cold stretching에 의한 구조변화를 알아보았다.

• Proceedings of the Membrane Society of Korea Conference
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• 2003.11a
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• pp.207-209
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• 2003

• Proceedings of the Korean Fiber Society Conference
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• 2001.04a
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• pp.145-148
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• 2001

• Proceedings of the Korean Nuclear Society Conference
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• 1999.05a
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• pp.306-306
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• 1999

• Korean Chemical Engineering Research
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• v.43 no.6
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• pp.704-714
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• 2005

Phase separations of Poly(4-vinylphenol)(PVPh)/Ethyl Acetate and PVPh/Butyl Acetate solutions were measured using the thermal optical analysis (TOA) method. The experimental phase separation data were correlated with liquid-liquid equilibria relations based on PC-SAFT equation of state. The phase separations of these system showed the behaviors of LCST (lower critical solution temperature)-type. The measured cloud temperatures were lowered with increasing in molecular weights of polymer(PVPh), and cloud temperatures of PVPh/Ethyl Acetate solutions shifted to lower temperature regions, compared to the PVPh/Butyl Acetate solutions. Extents of cross-association between solvent molecule and polymer in the PVPh/Ethyl Acetate solutions were measured using the FT-IR spectrum analysis method, and cross-association parameters of PC-SAFT model were estimated from experimental extents of cross-association. By using the estimated cross-association parameters between PVPh and solvent molecule, binodal and spinodal curves of liquid-liquid equilibria in PVPh/Ethyl Acetate and PVPh/Butyl Acetate solutions were calculated from PC-SAFT equation of state. The calculated binodal curves of these system were shown to be well agreeable with the experimental cloud temperature curves.

• Clean Technology
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• v.29 no.2
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• pp.109-117
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• 2023

The purpose of this study is to develop a method for separating antioxidants and sugars from grape skin extract. The extract was first mixed with a variety of organic solvents to investigate whether the separation was feasible. When employing acetone, ethanol, dimethylsulfoxide, or dimethylformamide, the organic solvent-extract combination formed a single phase. However, when benzene, ethyl acetate, or n-hexane was added to the extract, the mixture separated into an organic and an aqueous phase and the pigments remained in the aqueous phase. On the other hand, when polyethylene glycol-2,000 (PEG-2000) and sodium citrate were added to the extract, the mixture was separated into three layers, with the majority of the flavonoids migrating to the top layer and 53% of the extract's glucose migrating to the bottom layer. The top layer had significant antioxidant activity, whereas the bottom layer showed no antioxidant activity. The glucose recovery in the bottom layer increased as the molecular weight of PEG increased and the highest recovery (67%) was observed when PEG-8,000 was added. The highest flavonoid separation was observed with PEG-2,000, followed by PEG-8,000 and PEG-400. The flavonoid separation when PEG-2,000 was added resulted in a flavonoid recovery of 48% and 0.2% from the top and bottom layers, respectively. Examining the effect of the separated solution using the agar disc diffusion method on yeast cell growth confirmed that the addition of the extract, the top, and the bottom layer did not inhibit cell growth.