• Journal of Korean Society of Environmental Engineers
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• v.31 no.12
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• pp.1075-1080
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• 2009

The partial lipid degradation with the saturation of double-bond at the acidogenesis stage is known to help subsequent methanogenesis during anaerobic digestion. Acidogenic reactions in an anaerobic sequencing batch reactor (ASBR) and a continuously stirred tank reactor (CSTR) were carried out to compare their performances. A mixture of two unsaturated (oleate and linoleate) and two saturated (palmitate and stearate) long-chain fatty acids (LCFAs) was used as a model substrate. Biomass retention in the ASBR contributed to the enhanced performance at hydraulic retention time (HRT) below 15 hr. Biomass retention in the ASBR contributed to the enhanced performance compared to CSTR even at shorter HRT. ASBR would be a proper reactor configuration for the acidogenesis of lipid-containing wastewater.

• Journal of the Korean Chemical Society
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• v.25 no.4
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• pp.283-290
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• 1981

The reaction rates for the transesterification reaction were measured on the excess sucrose with the five fatty acid methyl ester systems such as methyl laurate, methyl myristate, methyl palmitate, methyl stearate and methyl oleate at temperature range of $50^{\circ}C$ to $90^{\circ}C$ in N,N-dimethylformamide solvent and potassium carbonate as a catalyst. Their activation parameters as well as rate constants were calculated from these measurements. And these reactions were found to be pseudo-first order and depended mainly on the structural changes in fatty acid residue of methyl esters. Also their reactions were found to be of enthalpy-controlled, which were disfavored in the order of methyl laurate, methyl myristate, methyl palmitate, methyl oleate and methyl stearate. Correspondingly their activation energies were 9.3, 9.9, 10.3, 10.9 and 11.1 kcal/mole, respectively.

• Polymer(Korea)
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• v.30 no.1
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• pp.22-27
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• 2006

The effect of transesterification on the rheological property of poly(ethylene naphthalate)/poly(butylene tore-phthalate) (PEN/PBT) blends has been investigated. The melt viscosity of PEN/PBT blends decreased with increasing PBT content due to the relatively low melt viscosity of PBT as well as introducing ransesterification between PEN and PBT Further melt viscosity decrease was achieved by the thermal annealing which caused both the chain scission and the acceleration of transesterfication. Calcium stearate (CaST) was applied as a lubricant in order to lower the melt viscosity of PEN and it was found that CaST was acting as the catalyst of transesterification as well. In general, reactive melt blending of PEN and PBT by transesterification resulted in the decrease of molecular weight of PEN and PBT, as a result, the loss of mechanical properties in PEN/PET blend was inevitable.

• Applied Chemistry for Engineering
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• v.3 no.4
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• pp.639-648
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• 1992

For recycling cement hydrate(CH) as waterproofers for mortar and concrete or a filler for rubber & plastics, the cement hydrates were treated with stearic acid(SA). And the bonding characteristics and the water repellency of the CH-SA compounds were investigated by using FT-IR, TGA, SEM, XRD, and contact angle measuring apparatus. Water tightness of the remitars used CH-SA compounds was also tested. The results are summarized as follows : 1) If the cement hydrates are treated with over 2.0% of stearic acid, the CH-SA compounds show very strong water repellency. 2) The stearic acids are solidified on the surfaces of cement hydrate in calcium stearate and aluminium stearate. 3) If CH-SA compounds which is cement hydrate treated with 5~10% of stearic acid are used 3%~6% in remitar, water absorption ratio and water permeatility ratio of remitar are decreased in below 30% of those of the ordinary remitar.

• Polymer(Korea)
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• v.30 no.2
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• pp.118-123
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• 2006

The effect of transesterification on the rheological properties in the melt reactive blending of poly(butylene terephthalate)(PBT) with poly(ethylene terephthalate)(PET) has been studied. The melt viscosity depression in PBT was found in PBT/PET blends due to the intrinsic low melt viscosity of PET compared to PBT. In addition, the thermal degradation in the melt blending and transesterification between two polyesters were considered as other factors fer the lowering of the melt viscosity in the blends. In the PBT/PET blends, calcium stearate was less effective than in PBT as a lubricant, however it accelerated both the thermal degradation and transesterification during melt blending. As a result, further melt viscosity drop was obtained in the reactive melt blending of PBT/PET.

• Journal of Adhesion and Interface
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• v.10 no.4
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• pp.182-190
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• 2009

In this work, effect of antistrip additives to reduce moisture damage of asphalt mixture were studied. Asphalt antistripping agents were prepared by condensation of formaldehyde with tetraethylene pentamine (TEPA), triethylenetetramine (TETA) and bis(hexamethylene)-triamine (BHMT), respectively. And also the metal type antistripping agent was prepatred by neutralization of stearic acid or palmitic acid with metal hydroxide. Mechanical characteristics of the asphalt mixture added antistripping agent were evaluated with Marshall stability, submerging residuals and coating rate. It was found that antistripping agent prepared in this study reduced moisture damages of asphalt mixtures. In particular, asphalt mixtures added BHMT and C/S (Calcium stearate hydroxide) antistripping agent showed highest submerging and coating rate. Because BHMT and C/S type antistripping agent was to improve bonding between asphalt and aggregate owing to increase of amine concentration and role of metal surfactant.

• Journal of the Korean Chemical Society
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• v.55 no.2
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• pp.163-168
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• 2011

The variations of molar conductivity of various surfactants such as sodium caprylate, sodium laurate, sodium palmitate, sodium stearate, sodium oleate, sodium dodecyl sulphate, and lithium dodecyl sulphate with concentrations of the surfactants for each of the solutions consisting of mixtures of varying concentrations of N-methyl acetamide in water at constant temperature of $30{\pm}0.2^{\circ}C$ were studied. The critical micelle concentration (CMC) for each surfactant is measured. It is found that the CMC values in mixtures of N-methyl acetamide and water solutions of various surfactants are lower than the CMC values in water, and the driving force for micelle formation correlates with solvophobicity. The surfactant-solvent interactions that drive amphiphilic self-organization in N-methyl acetamide in water are discussed. Thermodynamic parameters were evaluated for micellar system to explain the results.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.30 no.2
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• pp.153-158
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• 2004

In cosmetics, the saturated lecithin, one of the main surfactants to prepare liposome has been used for its stability but it has been substituting with unsaturated lecithin which has excellent skin affinity and penetration property. So we studied to prepare nano-liposome that size of particles were below than 50nm by unsaturated lecithin. It was important that many factors including solvent such as propylene glycol, pH balance, homogenizing pressure, various cosurfactants and stabilizers to make stable nano-liposome. In our experimental conditions, cosurfactants with stearate class as lipophilic part were more suitable than others for our purpose. But in liposome by saturated lecithin, cosurfactants had negative effect and appropriate amount of oil should be used to be stable. These results indicated that unsaturated lecithin were more suitable than saturated lecithin to prepare nano-liposome.

• Korean Journal of Food Science and Technology
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• v.21 no.5
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• pp.726-734
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• 1989

To analyze the components of dense coat fractions associated with fat globule membrane, The membrane was treated with various concentrations of Triton X-100, a non-ionic detergent, and the composition of lipids associated to the detergent insoluble material was analyzed. The amount of protein, phospholipid, cholesterol and ganglioside in milk fat globule membrane was reduced consistently with increasing concentrations of Triton X-100. Butyrophilin (band 12), xanthine oxidase (band 3) and band 16 as constituents of insoluble coat materials was revealed after electrophorisis on SDS-polyacrylamide gels. Phosphatidyl ethanolamine, phosphatidyl choline, phosphatidyl serine, phosphatidyl inositol and sphingomyelin were identified as the major phospholipids of the coat materials without selective concentration relative to the original membranes. Percentages of total phospholipid were not changed by any of the treatments. Fatty acids of total lipid were myristate, palmitate, stearate (major saturated acids), oleate and linoleate (major unsaturated acids). Cholesterol contents on a protein basis were slightly reduced with increasing concentrations of Triton X-100. Cholesterol adhered to protein more tightly than other constituents The contents of gangliosides was proportionally refuted with increasing concentration of Triton X-100.

• Polymer(Korea)
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• v.29 no.5
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• pp.475-480
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• 2005

The lowering of melt viscosity has been investigated to achieve the processability enhancement in poly(ethylene naphthalate) (PEN) melt processing by the reactive melt blending with poly(ethylene terephthalate) (PET) and introducing lubricant as well. CaST lubricant resulted in the lowering of PEN melt viscosity but noticeable mechanical property drop was found in PEN with more than $2wt\%$ of lubricant due to the acceleration of thermal degradation by excess lubricant. PEN/PET (90/10) blend has less melt viscosity than PEN and transesterification between two polymers caused the additional viscosity depression. further viscosity lowering was found in PEN/PET blend with CaST since CaST is acting as the catalyst of transesterification as well as a lubricant in PEN/PET blend.