• Journal of Industrial and Engineering Chemistry
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• 제67권
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• pp.123-131
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• 2018

Using mixed nonionic surfactants Span/Tween, we investigated the effects of HLB value on the O/W emulsion stability and rheological behaviors. In this study, MS-01 (Span 60 & Tween 60) and MS-02 (Span 80 & Tween 80) was used as mixed nonionic surfactants. We considered required HLB value 10.85 and selected corresponding HLB value range 8-13. The droplet size distributions, droplet morphology, rheological properties, zeta-potential and creaming index of the emulsion samples were obtained to understand the mechanism and interaction of droplets in O/W emulsion. The results indicated that optimal HLB number for O/W emulsions was 10.8 and 10.7, while using MS-01 surfactant and MS-02 surfactant respectively. MS-01 (HLB = 10.8) sample and MS-02 (HLB = 10.7) sample showed smallest droplet size and highest zeta-potential value. Rheological properties are measured to understand rheological behaviors of emulsion samples. All emulsion samples showed no phase separation until 30 days storage time at $25^{\circ}C$.

• 대한화장품학회지
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• 제38권3호
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• pp.201-207
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• 2012

Oil-in-ethanol (O/E) 마이크로에멀젼을 물에 희석하여 얻은 O/W 나노에멀젼의 성질에 대하여 다른 희석 과정의 영향을 연구하였다. 물/에탄올/비이온성계면활성제/실리콘 오일 계를 모델 계로 선택하였다. 희석과정은 물(또는 마이크로에멀젼)을 마이크로에멀젼(또는 물)에 단계별로 첨가하는 방법으로 구성되었다. O/E 마이크로에멀젼을 물에 첨가하여 혼합하면 30 nm 정도의 입경을 가진 나노에멀젼을 얻을 수 있었다. 반면에 물을 O/E 마이크로에멀젼에 첨가하면 400 nm의 입경을 가진 에멀젼을 얻을 수 있다. 희석 방법이 얻어지는 에멀젼의 성질에 중요한 역할을 하였다. 시간에 따른 나노에멀젼의 입자 변화는 관찰되지 않았으나 입자가 큰 에멀젼은 시간에 따라 입경이 증가하였으며 불안정화 기작은 오스트왈드 라이퍼닝으로 추정되었다.

• 대한화장품학회지
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• 제38권2호
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• pp.119-131
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• 2012

w/o 에멀젼은 내수성이 뛰어나고 보습 효과를 오랫동안 지속시킬 수 있으므로 화장품에 많이 사용하지만 안정도가 좋지 않기 때문에 안정한 w/o 에멀젼을 만들기 위해서는 전해질의 농도, 오일의 극성 정도, 수상의 비율, 유화제의 농도 등을 조절하는 것이 매우 중요하다. 안정도에 영향을 주는 여러 가지 요소 중에서 유화제의 구조에 따라 유화가능여부와 안정도가 어떻게 달라지는지에 초점을 맞추고, 유화제를 구조적으로 polyglyceryl ester 계열, silicone 계열, sugar 계열 유화제 등으로 나누어서 실험을 진행하였다. 또한 유상에 사용되는 오일의 실리콘 함량을 다르게 하여 유화제의 유화 능력을 검토하였다. 실험 결과를 참고하여 유화제에 따른 에멀젼의 입자, 점도의 경시 변화 등의 w/o 에멀젼의 특성을 찾아내고, 여러 조건에서 에멀젼의 안정도를 관찰하였다.

• 한국해양공학회지
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• 제14권2호
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• pp.44-52
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• 2000

The dispersion of surface oil is generally described as a break-up of oil slick into small oil droplets. These small droplets are subjected to turbulence and vertical circulation so that it can be entrained into subsurface. Sometimes they tend to be submerged into sea bottom permanently. The diameter of oil droplets is a critical parameter to determine their behavioral characteristics under water surface. At the same time the variations of droplet stability depends on the weathering of it. That is why the weathered oil has different mechanism from the unweathered one. The variability of physical properties of oil including viscosity and density contribute to interfere with effective separation of oil and emulsion droplets in water. Also in the presence of interactions among the droplets there are coalescing or coagulating effects on the dispersion process of droplets.

• 한국자동차공학회논문집
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• 제20권1호
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• pp.131-140
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• 2012

In this study, using the governing equation for thermohydrodyamic lubrication involving the homogeneous mixture of incompressible fluid derived by based on the principle of continuum mechanics, it is discussed the effects of water within engine oil on the performance of high speed journal bearing of a turbocharger. The governing equations are the general equations being able to be applied on the mixture of Newtonian fluid and non- Newtonian fluid. Here, the fluid viscosity index, n of power-law non-Newtonian fluid is supposed to be 1 for the application of the journal bearing in a turbocharger lubricated with the mixture of two Newtonian fluid, for example, water within engine oil. The results related with the bearing performance are shown that the bearing friction is to decrease and the side leakage and bearing load increase as increasing the water content in an engine oil.

• Journal of Dairy Science and Biotechnology
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• 제23권2호
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• pp.115-123
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• 2005

Microcapsules consisting of natural, biodegradable polymers for controlled and/or sustained core release applications are needed. Physicochemical properties of whey proteins suggest that they may be suitable wall materials in developing such microcapsules. The objectives of the research were to develop water-insoluble, whey protein-based microcapsules containing a model water-soluble drug using a chemical cross-linking agent, glutaraldehyde, and to investigate core release from these capsules at simulated physiological conditions. A model water soluble drug, theophylline, was suspended in whey protein isolate (WPI) solution. The suspension was dispersed in a mixture of dichloromethane and hexane containing 1% biomedical polyurethane. Protein matrices were cross-linked with 7.5-30 ml of glutaraldehyde-saturated toluene (GAST) for 1-3 hr. Microcapsules were harvested, washed, dried and analyzed for core retention, microstructure, and core release in enzyme-free simulated gastric fluid (SGF) and simulated intestinal fluid(SIF) at $37^{\circ}C$. A method consisting of double emulsification and heat gelation was also developed to prepare water-insoluble, whey protein-based microcapsules containing anhydrous milkfat (AMF) as a model apolar core. AMF was emulsified into WPI solution (15${\sim}$30%, pH 4.5-7.2) at a proportion of 25${\sim}$50%(w/w, on dry basis). The oil-in-water emulsion was then added and dispersed into corn oil ($50^{\circ}C$) to form an O/W/O double emulsion and then heated at $85^{\circ}C$ for 20 min for gelation of whey protein wall matrix. Effects of emulsion composition and pH on core retention, microstructure, and water-solubility of microcapsules were determined. Overall results suggest that whey proteins can be used in developing microcapsules for controlled and sustained core release applications.

• 대한화장품학회지
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• 제6권1호
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• pp.38-74
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• 1977

• 멤브레인
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• 제30권6호
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• pp.359-372
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• 2020

기름/물 분리막은 다른 분리 기술들에 비해 낮은 에너지 비용과 높은 성능 수준을 갖고 있다. 초친수성과 수중에서 소유성은 효과적인 기름/물 분리막을 개발하는 데 가장 중요한 요인으로 작용한다. 이와 더불어 방오속성과 생분해성도 효과적인 기름/물 분리막을 개발할 때에 고려되는 중요한 요소들이다. 본 리뷰 논문에서는 다양한 화학성분과 형태를 변형시켜 개발된 기름/물 분리막의 특성과 분리 효율을 개선한 연구들을 소개한다.

• 해양환경안전학회:학술대회논문집
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• 해양환경안전학회 2006년도 춘계학술발표회
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• pp.103-108
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• 2006

새롭게 적용되는 IMO 규정에 적합한 선박의 15ppm Bilge Separator를 개발하기 위하여 Bilge 폐수에 함유된 Emulsion 의 처리가 매우 중요하다. 에멀젼의 경우 그 안정성으로 인해 육상에서도 처리하기가 매우 까다로운데 본 연구에서는 화학적인 방법을 이용하여 Emulsion의 안정성을 파괴하여 처리하고자 하였다 파괴된 기름 입자는 서로 응집하여 부상처리 되는데, 선박은 특성상 장치의 설치장소가 협소하기 때문에 Bilge 폐수의 처리에 시간이 충분치 않다. 이러한 문제의 해결과 화학적 처리에 가장 기본이 되는 응집제의 선정과 기본적인 환경요인들을 결정하여 실험을 진행하였다. 실험결과 국내 제품 중의 응집제를 선정하였고 가장 응집 효과가 좋은 pH 영역과 응집제의 투여량을 결정하였으며 기초 실험을 통해 최적효율을 나타내는 부상방법을 결정하여 이를 바탕으로 Pilot Plant를 제작하여 에멀젼 함유 Bilge 폐수를 처리한 결과 IMO에서 정한 기준을 만족하는 결과를 얻을 수 있었다.

• 대한화장품학회지
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• 제22권2호
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• pp.132-140
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• 1996

The effect of a novel delivery system, water in oil emulsion containing chitosan hydrogel as a inner phase (W/O-C) was evaluated, and the relationships between the skin permeation, the skin primary irritation and the skin turnover rate of AHAs were discussed. We selected glycolic acid (GA), lactic acid (LA), malic acid (MA), and tartaric acid (TA) as model AHAs. The steady state fluxes of 4 AHAs across the excised hairless mouse skin increased as the molecular weights of the AHAs decreased. (GA>LA>MA>TA). The skin turnover times were shortened in all AHAs, compared with control. The skin permeation and the skin primary irritation of the LA decreased and the skin turnover time increased, as the pH increased. The maximum therapeutic index was obtained with pH 3.8, 0.5 M LA. It was suggested that the skin permeability of LA might be a main factor for prediction of the skin irritation and the skin turnover time. On the other hand, the W/O-C containing pH 3.8, 0.5 M LA indicated a good sustained release property of LA, compared with water in oil emulsion without chitosan hydrogel (W/O) or oil in water emulsion (O/W). The skin permeability and the skin irritation of AHAs from the W/O-C edcreased, compared with W/O or O/W, however the skin turnover time showed almost the same value as W/O or O/W. In conclusion, we suggest that the control of the skin permeation of AHAs would be an important tool for reducing the skin irritation and for maintaining the positive effect of AHAs, and the W/O-C system could be a potential candidate for future cosmetological application of AHAs.