• Polymer(Korea)
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• v.32 no.1
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• pp.19-25
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• 2008

The purpose of this study was improving the rheology properties of dentifrice by finding optimum binders polymer system which consists of carboxymethylcellulose (CMC), carbomer, and Mg/Al silicate. Response surface methodology (RSM) was employed to investigate the correlation between polymers and rheological properties of dentifrice and to optimize responses. Rheological properties were measured with oscillatory rheometer. As a result, it was identified that gel strength and yield stress were dependent on contents of CMC and carbomer and CMC caused long stringiness of dentifrice. And springness of dentifrice was dependent on contents of CMC and Mg/Al silicate. Optimum components proportion of polymers and silicate were obtained by responses optimization process. According to determined optimum components proportion, it was possible to observe a dentifrice with improved rheological properties.

• Archives of Pharmacal Research
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• v.7 no.2
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• pp.109-113
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• 1984

The critical micelle concentration (CMC) of crude ginseng saponin in water was determined by fluorometry and surface-tension measurement. These two methods gave the the CMC value, 0.015g/100ml AND 0.013G/100ml, respectively. The surface excess of the saponin and the area occupied by a saponin molecule at the monolayer adsorbed at air and waterinterface were calculated employing Gibbs adsorption equation. The presence of salt increased the surface activity of the saponin: it decreased the CMC, the surface tension at the CMC and the area occupied by a saponin molecule at the monolayer, which should be due to the salting-out effect of the salt.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.38 no.5 s.118
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• pp.38-46
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• 2006

Many researches for extensive uses of Hanji have been performed. With the advent of an information-oriented age, the development of Hanji which is printable has been considered as a new field of study. Since Hanji has many drawbacks in comparison with common printing papers, that is, rougher surface, huger absorption of ink and lower physical properties and printabilities. Improving the properties and printabilities of Hanji is therefore the most important work to deal with. This study was conducted to find out useful mixed agents for surface sizing suitable for printable Hanji. Four surface sizing agents (CMC, corn starch, PYA, AKD) were applied for mixture in this study. The physical properties of surface sized Hanji were measured. Results obtained were as follows. Based on designated agents according to concentration, each of the mixed agents was prepared. The kinds of mixture were corn starch (3%) and PVA (5%), corn starch (3%) and AKD (0.1%), corn starch (3%) and CMC (1%), AKD (0.1%) and CMC (1%), AKD (0.1%) and PVA (5%), CMC (1%) and PVA (5%). Each mixed surface sizing agents was included with these ratios (100:0, 90:10, 70:30, 50:50, 30:70, 10:90, 0:100) respectively. All the mixed agents improved the physical properties and printabilities of Hanji. Among them, mixed agent of CMC (1%) and corn starch (3%) with 90:10 ratio is superior to the others for not only smoothness but also ink printability. In view of the result achieved, it is regarded that it can be fit for using Hanji as a printing paper and turned out to be a good contribution to Hanji industry.

• Applied Chemistry for Engineering
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• v.16 no.6
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• pp.834-841
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• 2005

Polyethylene glycol esters (PEG-esters) were synthesized by condensation reaction of dicarboxylic acid such as adipic acid and sebacic acid and several PEGs. The PEG-esters were analyzed by FT-IR, $^1H-NMR$ and HPLC for structure analysis, and by GPC for molecular weight. Through the analysis of surface tension, critical micelle concentration (CMC), aluminum contact angle of water solution containing the PEG-ester, the synthetic PEG-esters are proven to exhibit surfactant properties. The surface tension ranged from 45 to 50 dyn/cm depended on the concentration and structures of the PEG-esters. The surface tension of PEG-esters with sebacic acid moiety and short polyoxyethylene unit resulted in lower value than that of PEG-ester with adipic acid moiety and long polyoxyethylene unit. The CMC of water solution containing 2.5 wt% PEG-ester with sebacic acid moiety estimated at $0.9{\times}10^{-5}{\sim}5.3{\times}10^{-3}mol/L$ depended on the structures of PEG-esters. The CMC of PEG-esters with long polyoxyethlene unit showed a higher value than that of PEG-esters with short polyoxyethylene unit. Meanwhile, the CMC of PEG-esters with adipic acid moiety was not distinct due to their high hydrophilic character. As the results of contact angle and cutting time aginst aluminum, the contact angle ranged from $45^{\circ}$ to $53^{\circ}$ depended on the concentration of PEG-esters. The cutting time of aluminum showed the shortest value at CMC, but the longest value above CMC. This fact indicates that the CMC of PEG-esters is a very important factor in drilling aluminum.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1996.10a
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• pp.52-57
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• 1996

Conductive Ceramic Matrix Composite(CMC) of TIC/Al2O3 and Metal Matrix Composite (MMC) of SiC/Al were experienced by the die sinking Electrical Discharge Machining(EDM) for different current and duty factor according to negative polarity. Inthis experimental study Material Removal Rate(MRR) maximum surface roughness four point bending stress distribution and Scanning Electron Microscopy(SEM) Photographs were analysed. the higher MRR was obtained for CMC than MMC but slowly decreased around duty factor of 0.67 for MMC and better surface morphology was found CMC than MMC. The SEM photographs of discharge traces for CMC showe uniform shape about 100 to 200${\mu}{\textrm}{m}$ in diameter but MMC showed irregular shape.

• Journal of the Korean Applied Science and Technology
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• v.29 no.1
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• pp.47-53
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• 2012

This study is concerned with coemulsifier which is better emulsifiable properties than emulsifier itselves' use only. It's compound was synthesized by esterification of propylene glycol and succinic acid. The structure of them was comfirmed with FT-IR and $^1H$-NMR. Surface active properties with surface tension, cmc, emulsing power were tested respectively at given conditions. Their surface tensions in the aqueous solution was decreased to 33-35 dyne/cm and their cmc was evaluated by surface tension method. And it's emulsifying power was excellent in jojoba oil. As results, the synthesized dipropylene glycol succinate is expected to apply as O/W coemulsifier.

• Journal of the Chungcheong Mathematical Society
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• v.34 no.4
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• pp.387-395
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• 2021

In this paper, we give a characterization of a Delaunay surface in ℝ³. Let Σ be a CMC-H surface in ℝ³ with H ≠ 0. If Σ meets a plane with constant contact angle along a circle, then it is rotationally symmetric, i.e., Σ is part of a Delaunay surface.

• Journal of the Korean Applied Science and Technology
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• v.33 no.3
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• pp.449-458
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• 2016

Detergency and surface active properties of mixed anionic surfactants with amphoteric and nonionic were investigated. Sodium dodecyl sulfate (SDS) and ammonium dodecyl sulfate (ADS) as anionic surfactants and cocamidopropyl betaine (CAPB) as an amphoteric surfactant were used. Nonionic surfactants, which are butyl glucoside (BG), octyl glucoside (OG), decyl glucoside (DG), lauryl dimethylamine oxide (AO) and saponin were also used. To study the synergy effects of mixed SDS/ADS anionic surfactant systems, amphoteric and nonionic surfactants were added into the mixed anionic surfactants. Investigated properties of surfactant mixtures were critical micelle concentration (CMC), surface tension (${\gamma}$), wettability. In addition, based on these properties, detergency of each sample was examined. Surfactant mixtures are anionics (SDS/ADS), anionic/amphoteric/nonionic (SDS/ADS/CAPB/saponin), and anionic/nonionic (SDS/ADS/BG/saponin, SDS/ADS/OG/saponin, SDS/ADS/DG/saponin, and SDS/ADS/AO/saponin). With the addition of amphoteric and nonionic to mixed anionic surfactants, CMC and ${\gamma}$ were decreased. Addition of CAPB, which is amphoteric, showed the best property at CMC and ${\gamma}$. Furthermore, as the chain length of hydrocarbon in alkyl glucosides was increased, the CMC and ${\gamma}$ were enhanced. However, the wettability did not exactly match up with CMC and ${\gamma}$. The surfactant mixture, which contained DG, showed the best performance at wetting time. Detergency was measured at various temperatures ($15^{\circ}C$, $30^{\circ}C$, $50^{\circ}C$). The cleaning performance was enhanced by increasing washing temperature. Moreover, detergency was influenced by not only CMC and ${\gamma}$ but also wettability. Although CMC and ${\gamma}$ were not minimum at surfactant mixture that included DG, the best cleaning performance showed in that sample.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.42 no.5
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• pp.74-82
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• 2010

Curtain stability without curtain contraction is critical for a successful operation in curtain coating, and this can be influenced by the change in particle dynamics and rheological properties of coating colors. In this study, polyvinyl alcohol (PVA) and carboxymethyl cellulose (CMC) were added to control the rheology of GCC based curtain coating colors. Surface tension was increased slightly with increasing content of cobinder. Shear-thinning of viscosity was more pronounced for the CMC containing GCC coating colors. Complex modulus decreased when small amount of PVA was used as a cobinder, but it increased in other coating colors. Extensional viscosity was increased with increasing of the cobinder content, but CMC was more effective. Results indicate that pigment interaction with PVA is different from that with CMC. Dispersibility of coating colors was improved due to steric stabilization when small amounts of PVA was used, but flocculation occurred by bridging when the amount of PVA was increased. Dispersibility of coating colors was improved when small amount of CMC was added, while flocculation was observed by depletion effect when the concentration of CMC was increased in coating colors. Addition of cobinders at proper levels gave positive effects both in rheological properties and curtain stability. On the other hand, excessive amount of cobinders caused particle flocculation and this resulted in rheological and curtain stablity problems.

• Korean Journal of Mathematics
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• v.25 no.4
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• pp.555-561
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• 2017

We show that a closed curve invariant under inversions with respect to two intersecting circles intersecting at angle of an irrational multiple of $2{\pi}$ is a circle. This generalizes the well known fact that a closed curve symmetric about two lines intersecting at angle of an irrational multiple of $2{\pi}$ is a circle. We use the result to give a different proof of that a compact embedded cmc surface in ${\mathbb{R}}^3$ is a sphere. Finally we show that a closed embedded cmc surface which is invariant under the spherical reflections about two spheres, which intersect at an angle that is an irrational multiple of $2{\pi}$, is a sphere.