• Clean Technology
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• v.16 no.2
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• pp.73-79
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• 2010

Vinyl acetate(VAc) was dispersion-polymerized using supercritical carbon dioxide that has many environmental advantages. To get poly(vinyl acetate) (PVAc) of larger molecular weights from conventional emulsion polymerization, VAc was polymerized at temperatures between 333.15 and 343.15 K and pressures between 20 and 40 MPa with initiator (0.5 ~ 5% of monomer) and silicone-based stabilizer (1 ~ 10% of monomer) for 2 ~ 50 hr. The resulting PVAc was analyzed to see the variations in the yield and the molecular weight. The final product of this research, PVA (poly(vinyl alcohol)), was prepared from PVAc by saponification. The effect of saponification conditions on the yield and the molecular weight of polymer were also studied.

• Applied Biological Chemistry
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• v.33 no.1
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• pp.43-51
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• 1990

Meat emulsions containing 0, 15, 30 and 45% of soy protein isolate(SPI), Na-caseinate(Na-CN) and their mixtures were prepared in order to determine the effect of these non-meat proteins on the physical properties and their sensory quality in emulsion type sausage. It was found that SPI was better fat stabilizer and better binder than Na-CN. The mixtures of SPI and Na-CN didn't exert any significant effect on emulsion stability. From the texture profile analysis by using Instron two-cycle compression tests, decrease in the substitution levels and increase in the ratio of SPI/Na-CN resulted in a significant increase in the textural values of hardness, adhesiveness, gumminess, chewiness. The finished products showed that the substituted product for 15 % meat protein had higher textural values than the unsubstituted product. The sensory quality evaluated for the final products showed no significant difference between the SPI substituted product for 15 % meat protein and the unsubstituted product. However, all of the substituted products for 15 % meat protein and some of those for 30 % substitution with SPI and 67 % SPI received higher scores than average.

• Korean Journal of Food Science and Technology
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• v.22 no.3
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• pp.319-324
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• 1990

The effects of pH, protein and fat content, addition of emulsifiers, stabilizer, sugar, salt and calcium salt on the stability of soymilk suspension were investigated by analyzing the cream separated and precipitates of soymilk which is prepared by various conditions. In the alkaline region of pH, soymilk showed a good stability of the suspension and particularly, above pH 10, precipitates were not formed. When 1.5% of palm oil with 0.4% of glycerine monostearate was added to soymilk in the hydrophile-lipophile balance (HLB) value of 4 to 7, resulted maximal emulsion stability occured below H LB 6. The stability was decreased with increasing the fat concentration and soy oil showed better emulsion stability than that of palm oil. Among the commercial stabilizers, 0.03% of carrageenan was most effective. The stability was not decreased by addition of sugar up to 3% while it was decreased by addition of sodium salt and calcium salt at low level.

• Bulletin of the Korean Chemical Society
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• v.32 no.5
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• pp.1534-1538
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• 2011

Uniform, hollow nanosilica spheres were prepared by the chemical coating of cationic polystyrene (cPS) with tetraethylorthosilicate (TEOS), followed by calcination at 600 $^{\circ}C$ under air. cPS was synthesized by surfactant-free emulsion polymerization using 2,2'-azobis (2-methyl propionamidine) dihydrochloride as the cationic initiator, and poly(vinyl pyrrolidone) as a stabilizer. The resulting cPS spheres were 280 nm in diameter, and showed monodispersion. After coating, the hollow silica product was spherically shaped, and 330 nm in diameter, with a narrow distribution of sizes. Dispersion was uniform. Wall thickness was 25 nm, and surface area was 96.4 $m^2/g$, as determined by BET. The uniformity of the wall thickness was strongly dependent upon the cPS surface charge. The effects of TEOS and ammonia concentrations on shape, size, wall thickness, and surface roughness of hollow $SiO_2$ spheres were investigated. We observed that the wall thicknesses of hollow $SiO_2$ spheres increased and that silica size was simultaneously enhanced with increases in TEOS concentrations. When ammonia concentrations were increased, the irregularity of rough surfaces and aggregation of spherical particles were more severe because higher concentrations of ammonia result in faster hydrolysis and condensation of TEOS. These changes caused the silica to grow faster, resulting in hollow $SiO_2$ spheres with irregular, rough surfaces.

• Korean Journal of Food Science and Technology
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• v.6 no.2
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• pp.91-97
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• 1974

This paper was developed for production of the humanized milk, comprising similarly to the composition and characteristic of human milk. Humanized milk of superior quality can be made directly from the fresh raw milk mixed vegetable oil, corn syrup, whey powder, ${\beta}-lactose$, sugar, vitamin, ${\beta}-carotene$ and minerals showing formulation of the humanized milk at table 2. The improving effects of adding vegetable oil and corn syrup are both more reformed the chemical and physical properties of humanized milk. The former enhanced the essential fatty acid and energy source in this product, the latter has the most solving function in water and induced amount of emulsion and stabilizer. The products contain about 13% protein, 23% fat, 58.3% carbohydrate, 2% ash and ensue reasonably balance of essential amino acid, poly-unsaturated fatty acid for the requirement of infants and controlled component of the humanized milk such as human milk.

• Journal of Pharmaceutical Investigation
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• v.38 no.1
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• pp.39-43
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• 2008

Cyclosporin A (CyA), a potent immunosuppressive drug used in allogeneic transplants and autoimmune disease, is a typical water-insoluble drug. Recently, nanoparticle carriers were investigated to improve the intestinal absorption of drugs. In this study, CyA-loaded nanostructured lipid carriers (NLCs) were prepared from a hot o/w emulsion using the high pressure homogenization method. The NLCs were consisted of cationic lipids, solid lipids, liquid lipids (oils), surfactant and stabilizer. Encapsulation efficiency of CyA in NLCs was approximately 71%. The average particle size and zeta potential of NLCs were below 250 nm and above +40 mV, respectively. The morphology of NLCs was confirmed by transmission electron microscopy (TEM) analysis. Compared to the CyA powder, higher in vitro release of CyA from NLCs was observed after burst release within 30 min. Thus, CyA-loaded NLCs could be applied not only for parenteral route but also for gastrointestinal administration, which needs further investigation.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.35 no.2
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• pp.103-110
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• 2009

The objective of this study is to analyze the influences of fatty alcohols and fatty acids on rheological properties of oil in water (O/W) emulsions using viscosity and rheograms. As the chain length of fatty alcohols and fatty acids lengthened, the viscosity of emulsions was increased. The influence of fatty alcohols on viscosity enhancement was stronger than that of fatty acids. Both stearyl alcohol and cetearyl alcohol, which have carbon chain length similar to lipophilic portion of surfactant used in emulsion preparation, had showed the best increase in viscosity of O/W emulsions. O/W emulsions prepared with fatty alcohols and fatty acids were pseudo-plastic fluid and they showed shear thinning behaviour like as the common cosmetic emulsions. O/W emulsions prepared with cetyl alcohol, cetearyl alcohol and stearyl alcohol were thixotropic fluids and thixotropy increased with an increase in the concentration of fatty alcohols and fatty acids. Also O/W emulsions prepared with fatty alcohols were more thixotropic than those prepared with fatty acids. For the sake of viscosity increase related to O/W emulsions stability and spreadability enhancement related to payoff, it is thought that fatty alcohols are more useful than fatty acids in the O/W emulsions as the emulsion stabilizer.

• Korean Chemical Engineering Research
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• v.50 no.6
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• pp.1076-1081
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• 2012

For the purpose of development of the latex suitable for latex modified concrete, experimental researches on the preparation of carboxylated styrene butadiene latex by the method of the two-step emulsion polymerization and application to concrete were performed. Sodium dodecylbenzene sulfonate and sodium salt of lauryl sulfonate were selected as anionic emulsifiers, and nonylphenoxy poly(ethyleneoxy) ethanols (n=10, 20, 40) as latex stabilizer. Potassium persulfate and sodium bisulfite were used as redox initiator, besides $Na_2HPO_4$ and $K_2CO_3$ as electrolytes. Polymerization recipe of latex suitable for latex modified concrete were suggested from the experimental researches on the effects of anionic emulsifiers and their concentration on the polymerization stability, and the effect of electrolytes concentration on the particle size of latex. Physical properties, such as slump, air contents, compressive and flexural strength, of latex prepared by suggested polymerization recipe were examined. The experimental results showed that latex modified concrete satisfied the quality standards in slump and air contents. Furthermore, it was turned out that the compressive and the flexural strength of latex modified concrete with 28 days curing time showed appreciably improvements.

• Applied Chemistry for Engineering
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• v.24 no.4
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• pp.357-362
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• 2013

Monodispersed polystyrene latex spheres (PLS) and PS-MPS/silica composite nanospheres were used to test high efficiency particulate air (HEPA) filters. Prior to filter tests, all nanospheres used in this work were characterized by measuring their average particle diameters and coefficients of variation (CV) for assessing them as artificial dusts. The average particle sizes of PLS and composite nanospheres could be well controlled in the range of 100~300 nm well by changing reaction temperature and the amount of a stabilizer during emulsion polymerization. The CV of all nanospheres were also in the range of 3~7%, lower than 15% that is the criterion for monodispersed particle distributions. Furthermore the results of HEPA filter tests show that all nanospheres used were quite proper as artificial dusts for testing air filters.

• Korean Chemical Engineering Research
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• v.50 no.5
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• pp.789-794
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• 2012

For the purpose of development of the latex suitable for polymer cement mortar, experiments on the preparation of carboxylated styrene butadiene latex by the method of the two-step emulsion polymerization were performed. Methyl methacrylate, methacrylic acid and acrylic acid were selected as carboxylic co-monomer, styrene and butadiene as monomer, sodium dodecylbenzene sulfonate and sodium salt of lauryl sulfonate as anionic emulsifiers, and nonylphenoxy poly (ethyleneoxy) ethanol (n=10, 20, 40) as latex stabilizer. Potassium persulfate and sodium bisulfite were also used as redox initiator, and sodium monohydrogen phosphate and potassium carbonate as electrolytes. The effects of categories and concentration of carboxylic co-monomer, molecular weight control agent, crosslinking agent, and styrene/butadiene monomer ratio on the characteristics of latex were investigated. Polymerization recipes for preparation of polymer cement mortar could be proposed. The prepared latexes were tested for the physical properties such as compressive and flexural strength when latexes were mixed with cement mortar. The results showed that the latex could be adapted to polymer cement mortar. Also, it was recognized that the compressive and flexural strength were exhibited 25.4% and 45.3% respectively higher improvement than the quality standards at 28 days curing time.