• Proceedings of the Korea Concrete Institute Conference
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• 2005.11a
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• pp.793-797
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• 2005

This study was undertaken to examine the feasibility of recycling waste concrete fine aggregate to prepare polymer-modified mortars. The specimens of polymer-modified mortars were prepared by using styrene-butadiene rubber(SBR) latex and polyacrylic ester(PAE) emulsion as a polymer modifier. The formulations for specimens were prepared with various replacing ratios of waste concrete fine aggregates as parts of standard sand and various polymer cement ratios. For the evaluation of the performance of polymer-modified mortars, various physical properties were investigated. As a results, water cement ratio of polymer-modified fresh mortars increased with an increase of recycled fine aggregate, but decreased with an increase of polymer modifiers. The compressive and flexural strengths of polymer-modified mortars decreased with an increase of recycled fine aggregate, but flexural strengths increased with an increase of polymer modifiers.

• Journal of Adhesion and Interface
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• v.12 no.4
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• pp.117-124
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• 2011

This study was made on the poly(vinyl acetate) (PVAc) and poly(vinyl acetate- ethylene) (VAE) emulsion polymer blend which used PVA as protective colloid, and the PVA used as protective colloid was existed in each emulsion film before blend and even in the film after the blend consecutively. It makes us expect excellent adhesive power among particles that form the blend. Emulsion blends with different Tg are important target of concerning, and PVAc/VAE emulsion blend suggested simple and excellent research method. As a result of blend, elongation was lowered by the increase of PVAc, and the plasticizer used in making PVAc affected on the Tg of blend and lowered Tg of VAE emulsion, and the synergy effect of two blends was seen for the tensile strength, thermal resistance, and adhesive strength.

• Proceedings of the PSK Conference
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• 2003.04a
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• pp.299.2-300
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• 2003

Various bupivacaine-Ioaded microspheres were prepared with poly (d,l-Iactide) (PLA) by solvent extraction method. The internal solution of polymer(PLA R104) and drug in glacial acetic acid was introduced into the external phase of polyvinylpyrrolidone (PVP K-30) in polyethyleneglycol (PEG), and emulsified to be an oil-in-oil (o/o) emulsion. The o/o emulsion was poured to the buffer solution. (omitted)

• Journal of Adhesion and Interface
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• v.3 no.4
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• pp.27-36
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• 2002

The organic/organic core-shell composite polymer for nonwomen binder were synthesized by stage polymerization of methyl methacrylate and styrene with ammonium persulfate after preparing monomer pre-emulsion in the presence of anionic surfactant. We study the effect of initiator concentration, $0.79{\times}10^{-3}{\sim}3.16{\times}10^{-3}mol/L$ for core polymer, $2.0{\times}10^{-4}{\sim}8.0{\times}10^{-4}mol/L$ for shell polymer, sulfactant concentration, $1.45{\times}10^{-5}{\sim}4.15{\times}10^{-5}mol/L$ for core polymer, $0.73{\times}10^{-5}{\sim}2.91{\times}10^{-5}mol/L$ for shell polymer on core-shell structure of polymethyl methacrylate/polystyrene and polystyrene/polymethyl methacrylate. Emulsion stability was major test method, particle size and particle size distribution were measured using particle size analyzer and the morphology of the core-shell composite polymer was determined using transmission electron microscope, glass temperature was also measured using differential scanning calorimeter.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.536-539
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• 2004

A novel ink-jet printing method was investigated for fine patterning of phosphor layer in PDP using a precision nozzle printing. A reverse emulsion method was developed for the synthesis of nano-sized phosphor powder that could be formulated in the phosphor ink. The composition of the phosphor ink including charge controlling agents, solvent, dispersant and nano-sized phosphor powder was optimized for the fine patterning of phosphor layer for high resolution PDP.

• Proceedings of the Korea Concrete Institute Conference
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• 1993.04a
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• pp.93-98
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• 1993

In order to discuss the mechanical properties of fiber reinforced composites with fly ash, lime, gypsum and polymer emulsion-Stylene Butadiene Rubber Latex (SBR) , experimental studies on FRC were carried out. The kinds of fiber used in FRC are PAN-dervied and Pitch-derived carbon fiver, alkali-resistance glass fiber. As a test results, the flexural strength and tougthness of fiber reinforced fly ash. lime.gypsum cement composites are remarkably increased by fiber contents ,but compressive strength of the composites are influenced by kinds of fiber more than by fiber contents. Also, addition of a polymer emulsion (SBR) to the composites decreased the bulk specific gravity, but compressive and flexural strengths, toughness of the composites are not influenced by it, are considerably improved by increasing fiber contents.

• Elastomers and Composites
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• v.31 no.3
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• pp.175-182
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• 1996

Polymer latices, prepared from the emulsion polymerization of vinyl monomer compounds, are widely used for many industrial applications. Included among these are uses in paints, adhesives, flocculants, and heavy-duty plastics as well as their original use in synthetic rubber compounds. The emulsion polymerization process with chemical initiator has chemical disadvantage such as removal of initiator which was left after polymerization. In this study, polystyrene latex was prepared by using ultrasonic irradiation which generate the free radical, and then it was analyzed by GPC. Reaction temperature hardly have an effect on average molecular weight. Average molecular weight is increased by increasing amount of surfactant, i.e. SDS, but polydispersity is decreased. After 90 minutes of reaction time, increase and decrease of average molecular weight Is repeated. It is proposed that monodisperse polymer is obtained by controlling ultrasonic irradiation time and surfactant concentration.

• Magazine of the Korea Concrete Institute
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• v.10 no.5
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• pp.217-225
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• 1998

분쇄한 FRP(Fiver-Reinforced Plastics) 폐기물을 사용한 폴리머 모르타르의 물성에 고나하여 조사하였다. 분쇄한 FRP 폐기물을 시멘트 모르타르의 세골재로 재활용하기 위하여 세골재에 대하여 0~50wt% 치환.사용하였고, FRP 폐기물의 사용으로 나타나는 강도 저하현상을 보완하기 위하여 3종류 폴리머 혼화제의 첨가량을 변화시켜 각종 공시체를 제작하였다. 폴리머 혼화제로서는 styrene-bytadiene rubber(SBR) 라텍스, polyacrylic ester(PAE) 에멀젼 및 ethylene-vinyl acetate(EVA)에멀젼을 사용하였다. 분쇄한 FRP 폐기물을 사용한 시멘트 모르타르에 폴리머 혼화제를 첨가하여 만든 폴리머 시멘트 모르타르는 폴리머 혼화제를 첨가하지 않은 모르타르보다 압축 및 휨강도가 크게 증가하였다. 폴리머 시멘트비 10wt%에서 세골재 대용으로 분쇄한 FRP 폐기물의 적정 치환량은 20wt%로 나타났다. 8$0^{\circ}C$에서 가열양생하여 제조한 폴리머 시멘트 모르타르는 폴리머 시멘트비 10wt%이하에서 표준양생한 모르타르보다 강도가 저하되었다. 폴리머 시멘트 포르타르의 흡수율은 폴리머 시멘트비가 증가함에 따라 크게 감소하였다.

• Korea-Australia Rheology Journal
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• v.15 no.3
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• pp.125-130
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• 2003

The emulsion stability of cosmetic creams based on the water-in-oil (W/O) high internal phase emulsions (HIPEs) containing water, squalane oil and cetyl dimethicone copolyol was investigated with various compositional changes, such as electrolyte concentration, oil polarity and water phase volume fraction. The rheological consistency was mainly destroyed by the coalescence of the deformed water droplets. The slope change of complex modulus versus water phase volume fraction monitored in the linear viscoelastic region could be explained with the resistance to coalescence of the deformed interfacial film of water droplets in concentrated W/O emulsions: the greater the increase of complex modulus was, the more the coalescence occurred and the less consistent the emulsions were. Emulsion stability was dependent on the addition of electrolyte to the water phase. Increasing the electrolyte concentration increased the refractive index of the water phase, and thus decreased the refractive index difference between oil and water phases. This decreased the attractive force between water droplets, which resulted in reducing the coalescence of droplets and increasing the stability of emulsions. Increasing the oil polarity tended to increase emulsion consistency, but did not show clear difference in cream hardness among the emulsions.

• Journal of the Korean Applied Science and Technology
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• v.23 no.1
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• pp.1-11
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• 2006

The W/O emulsion was formed by mixing hydrophobic nonion surfactants of span 80 and tween 60 with kerosine, and by adding sodium silicate aqueous solution. Precipitating the W/O emulsion by sodium bicarbonate resulted in spherical silica particles. Shape and size distribution of silica particles were observed. The particles were spherical and they have narrow size distribution. Particle sizes were 9.29, 7.39 and $5.73\;{\mu}m$ at homogenizer speed of 2500, 3000, and 3500 rpm, respectively. The particle size was decreased by increasing agitation speed due to the formation of emulsion droplet. At fixed agitation speed, absorbed paraffin oil weight were measured and the $SiO_2/Na_2O$ mole ratio effects on particle size were investigated. Particle size was decreased by increasing the mole ratio of $SiO_2/Na_2O$.