• Applied Chemistry for Engineering
• /
• v.8 no.6
• /
• pp.979-984
• /
• 1997

Test specimens of polymer-cement concrete composites were prepared using styrene-butadiene rubber(SBR) latex, ethylenevinyl acetate(EVA) and polyacrylic ester(PAE) emulsions as polymer dispersions in cement modified system at constant slump($10{\pm}0.5cm$), then compressive and flexural strengths water absorption, pore size distribution, and microstructures were investigated. Compressive and flexural strengths of these composites were remarkably improved with an increase of polymer-cement ratio. These composites had a desirable pore size distribution against frost damage due to a small capillary pore volume. Continuous polymer film was able to form in higher than 15% of polymer cement ratio.

• Food Science and Biotechnology
• /
• v.18 no.5
• /
• pp.1161-1172
• /
• 2009

Food nanoemulsion systems consisting of water and oleoresin capsicum (OC), polyoxythylene sorbitan esters (Tween 20, 40, 60, and 80), propylene glycol (PG), sucrose monostearate (SM), and their corresponding mixtures were formulated to use as food vehicles. Tween 80 produced OC nanoemulsions with stable dispersions as one-phase systems, and the dertermined emulsification efficiencies clearly distinguished the ability of the various surfactants to emulsify OC. The nanoemulsions were prepared by both ultrasonication and self-assembly, and the nanoemulsion areas were determined using phase diagrams by measuring the sizes of the emulsions. One-phase nanoemulsions were presented, with a multiple cloudy region and phase separation that were dependent on the particle size of the emulsion. The OC nanoemulsions prepared by ultrasonication using systems of OC/Tween 80/water, OC/Tween 80/water+PG, and OC/Tween 80/water+SM, resulted in particle sizes ranging from 15 to 100 nm. Finally, the nanoemulsions maintained their initial sizes during storage, ranging from 65 to 92 nm.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.22 no.2
• /
• pp.167-173
• /
• 1996

The stability of gel structured emulsion and the effect of polyols on it have been studied by rheological property and interfacial tension. In this paper, three types of gel structured emulsions were prepared by using three polyols respectively(glycerine for sample 1, 1.3 BG for sample 2, PG for sample 3). And both complex modulus($G^*$) and loss angle[$\delta$ = tan-1(G"/G')] of samples were investigated against oscillating shear stress and frequency($\omega$). The results show sample 1 is most highly consistent with oscillating shear stress. And the results were compared with those of accelerated tests concerning storage stability of gel structured emulsion. To correlate consistency of rheological property with storage stability, interfacial tension from which adsorption efficiency of surfactant(Octyldodecyl Ether) could be known was measured. Sample 1 showed the largest value of [$d{\gamma}/dIn_{Cconc. of surfactant}$] in Gibbs equation. In summary, the prediction of stability could be correctly made by the consistency of rheological property(G*,$\gamma$) of gel structured emulsion against oscillating shear stress and it could be supported by measuring interfacial tension. And polyol affected the value of [$d{\gamma}/dIn_{Cconc. of surfactant}$], consequently affected the stability.lity.

• Journal of the Korean Applied Science and Technology
• /
• v.21 no.4
• /
• pp.267-273
• /
• 2004

It has been 40 years since emulsion inversion was observed. Emulsion inversion is a phenomenon in which O/W emulsion inverts to W/O emulsion or vice versa. In other words, the dispersed and continuous phase of an emulsion is reversed after emulsion inversion takes place. For three-phase emulsions, not only emulsion inversion but also emulsion transition has been observed. In emulsion transition the continuous phase of an emulsion remains unchanged, but the dispersed emulsion drops, which is basically a two-phase emulsion, experience emulsion inversion at a certain temperature. Such temperature is called the emulsion transition temperature. Emulsion transition was a product of theoretical speculation and was experimentally observed for a couple of ternary amphiphile/oil/water systems. This phenomenon is a novel one, which has been unreported to date. In this article emulsion inversion and emulsion transition are compared and discussed.

• Journal of Adhesion and Interface
• /
• v.3 no.1
• /
• pp.13-19
• /
• 2002

We have studied on the surface and adhesion properties for acrylic terpolymers, having both hydrophobic and hydrophilic side chains, synthesized via solution polymerization. In order to develop a waterborne material. we tried to synthesize these terpolymers via emulsion polymerization. The polymeric emulsion synthesized was mainly composed of methyl methacrylate (MMA), methoxy-polyethyleneglycol methacrylate (MPEGMA) having hydrophilic side chains and methoxypolypropyleneglycol methacrylate (MPEGMA) having hydrophobic side chains. The viscosities of this series increased with an increase in the content of the co-monomer such as MPEGMA and (MPEGMA). This behavior resulted in the increase in the diameter and heterogeneity of the emulsion particle via AFM observation. Furthermore. the tensile adhesion strength and 90-degree peel strength of the adhesive of these polymeric emulsions were measured. In the case of polymeric emulsion composed of the same content of both hydrophilic and hydrophobic component, the adhesion property showed the highest value. However, since the adhesion properties as a practical applicable adhesive were poor, some improvements were required. When the composition above was modified with butyl acrylate (BA), the improvement effect on adhesion strength was accepted. In particular, 90-degree peel strength increased up to a maximum of 400% of the original value.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.11 no.1
• /
• pp.13-20
• /
• 1985

The decreased preservative effect by tale and $TiO_2$ for emulsions obtained with polyoxyethylene surfactant was studied by various analytical methods and biological test. The preservative effect of methyl p-hydroxybenzoate was decreased by the addition of talc and $TiO_2$ and this result was attributed to the adsorption of methyl p-hydroxybenzoate on them. Talc exhibited more decreased preservative effect than that of $TiO_2$. The amount of the adsorption of methyl p-phydroxybenzoate by talc at $20^{\circ}C$ could be represented by the following equation; $a=11.511C^{0.747}$.

• Journal of ILASS-Korea
• /
• v.16 no.3
• /
• pp.152-158
• /
• 2011

Fast pyrolysis of biomass is one of the most promising technologies for converting biomass to liquid fuels. The pyrolysis oil, also known as the bio crude oil (BCO), have been regarded as an alternative fuel for petroleum fuels to be used in diesel engine. However, the use of BCO in diesel engine requires modifications due to low energy density, high water contents, low acidity, and high viscosity of the BCO. One of the easiest way to adopt BCO to diesel engine without modifications is the use of BCO/diesel emulsions. In this study, a diesel engine operated with diesel, bio diesel (BD), and BCO/diesel emulsion was experimentally investigated. Performance and emission characteristics of a diesel engine fuelled by BCO/diesel emulsion were examined. Results showed that stable engine operation was possible with emulsion and engine output power was comparable to diesel and bio diesel operation. Long term validation of adopting BCO in diesel engine is still needed because the oil is acid, with consequent problems of corrosion especially in the injection system.

• Journal of Adhesion and Interface
• /
• v.13 no.2
• /
• pp.89-93
• /
• 2012

In this study, the properties of acryl emulsion with adjunction procedures of tackifier resin and tackifier emulsion were investigated. Glass transition temperature of acryl emulsions was increased with the content of tackifiers. The initial strength showed the maximum value when the contents of tackifier resin and tackifier emulsion were 10 phr and 15 phr, respectively. Additionally, the strengths on heat and water resistances were increased with the contents of tackifier.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.21 no.2
• /
• pp.94-111
• /
• 1995

In this study, the relationship between partition coefficients(Kw) of oils and antimicrobial effects Ivas investigated. The antimicrobial activity of paraben has been known to be controlled by the concentration of the paraben in the aqueous phase. The concentration of paraben in the aqueous phase was measured by the UV/VIS spectrophotometer at the wavelength of 256nm. It was found that the hydrocarbon oils and silicone oils had the lowest Kw value(<1.0) among the tested oils. Also, the emulsions which were made of oils having low Kw values had a good antimicrobial effects. Thus, the cosmetic safety against microorganisms could be improved by using the oils which have low Kw values.

• Korean Chemical Engineering Research
• /
• v.56 no.2
• /
• pp.143-150
• /
• 2018

Oil-in-water emulsion was prepared using cinnamoyl surfactants as emulsifiers. Cinnamoyl surfactants used in the present study were polyoxyethylene (20) sorbitan monolaurate-cinnamic acid conjugate (TW20CA), polyoxyethylene (20) cetyl ether-cinnamic acid conjugate (CE20CA), and polyoxyethylene(20) oleyl ether-cinnamic acid conjugate (OE20CA). The emulsion stabilized with TW20CA was the most stable, possibly because the polyoxyethylene segment of TW20CA would sterically stabilize the oil droplets effectively. In vivo UV protecting efficacy of surfactant and emulsion was investigated by determining the minimum amount of UV light (MAUL) to induce a black point on the back of hairless mice (HRM2). The mean MAUL of PARSOL, OE20CA, and emulsion stabilized with TW20CA was $1046.5mJ/cm^2$, $1163mJ/cm^2$, and $1308.5mJ/cm^2$, respectively. The high UV-protecting efficacy of the emulsion could be ascribed to not only the UV-absorbing property of cinnamoyl group but also the UV-scattering property of the oil droplets.