• Elastomers and Composites
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• v.48 no.3
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• pp.190-194
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• 2013

In this study, sebacic acid made from castor oil was used as monomer with isophthalic acid and glycols for polyester polyol synthesis. Polyurethane adhesive was synthesized from the various polyester polyol. From the result of adhesion strength test, polyester polyol made from sebacic acid showed better adhesive force than that of adipic acid due to higher cohesive energy. Branched glycol containing methyl group represented better adhesion than linear glycol. In the chain extender, adhesion strength increased going from PG, EG, BD. From the measurement of TGA, BD showed the best heat stability, and followed by PG, EG. Glass transition temperature increased in the order PG, EG, BD by the result of DMA.

• Journal of the Korean Chemical Society
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• v.4 no.1
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• pp.13-14
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• 1957

Th-determination by the sebacic acid method was compared with the hydrogen peroxide method. The former is a little more complicated than the latter in the operation and at the same time it requires careful pH adjustment, but the time needed for determination could be decreased greatly by the former. As a result of the comparison between both methods we confirmed that, within ${\pm}$0.08 ${\%}$ of error, when $ThO_2$ was contained $5{\%}$ in the sample, we could use the sebacic acid method with an half time of that required for the hydrogen peroxide method. Thorium in Monazite sand was also determined by both methods and compared. In the case we found, too, that if we permitted the maximum error of ${\pm}$0.08 ${\%}$, we could prefer the sebacic acid method.

• Elastomers and Composites
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• v.49 no.1
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• pp.31-36
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• 2014

Polyester polyols were synthesized by using each one mole of sebacic acid, isophthalic acid, ethylene glycol, and neopentyl glycol. The synthesized polyol had 56.6 mg KOH/g of hydroxy value and 1980 g/mole of molecular weight. From FT-IR structure analysis of polyester polyol, Hydroxy group(-OH) was observed around 3600 $cm^{-1}$, -CH shoulder of sebacic acid at 2950 $cm^{-1}$, carbony group of ester around 1730 $cm^{-1}$, and benzene ring of isophthalic ring was represented at 1600 $cm^{-1}$, 740 $cm^{-1}$. In case of polyurethane, hydroxy peak was showed at 3600 $cm^{-1}$, and -NH group around 3300 $cm^{-1}$, 1530 $cm^{-1}$. From $^1H$ NMR measurement of polyester polyol, it was found that sebacic acid was represented at 1.3, 1.5, 2.1 ppm, isophthalic acid at 7.3, 8.1, 8.7 ppm, ethylene glycol at 4.2 ppm, and neopentyl glycol at 0.8, 3.2, 3.9 ppm, respectively. In the polyurethane, it is almost the same as spectrum of polyester polyol, but showed very week peak at 7 ppm by benzene ring of toluene diisocyanate.

• 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.

• Polymer(Korea)
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• v.37 no.3
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• pp.294-301
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• 2013

Polymersomes made of biodegradable triblock copolymers based on poly(fumaric acid-co-sebacoyl chloride)/PEG (PEG-co-P(FA/SC)-co-PEG) were prepared and studied in aqueous solutions. TEM confirmed the formation of vesicles in aqueous media. Aggregation behavior of the copolymers was studied by fluorescence spectroscopy of 8-anilino-1-naphthalenesulfonic acid, and the critical aggregation concentration (c.a.c.) of the copolymer was found to be ${\sim}26.2{\mu}M$ indicating desirable stability of the vesicles. Dynamic light scattering revealed that the size of the vesicles was distributed within the range of 170-270 nm. Turbidity measurements confirmed the relative short-term stability of the polymersomes. Carboxyfluorescein, a hydrophilic compound, was simply encapsulated in the vesicles during polymersome preparation. The release of encapsulant from the polymersomes at 25 and $37^{\circ}C$ lasted about 3 weeks, and the rate of release followed a first-order kinetics. The release is speculated to be primarily carried out through diffusion. These results confirm that these polymersomes are promising as controlled-release carriers of various drugs.

• Korean Journal of Pharmacognosy
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• v.38 no.3 s.150
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• pp.222-226
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• 2007

Seven compounds, scopoletin (1), p-hydroxyphenethyl trans-ferulate (2), $1-({\alpha}-L-rhamnosyl(1\;{\rightarrow}\;6)-{\beta}-D-glucopyranosyloxy)-3,4,5-trimethoxybenzene$ (3), benzyl ${\alpha}-L-rhamnopyranosyl(1\;{\rightarrow}\;6)-{\beta}-D-glucopyranoside$ (4), suberic acid (5), sebacic acid (6) and scopolin (7) were isolated from the methanol extract of the roots of Althaea rosea Canival. Compounds $1\;{\sim}\;7$ were first isolated from this plant. The isolated compounds were tested for their cytotoxicity against human cancer cell lines using a SRB method in vitro.

• Elastomers and Composites
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• v.54 no.4
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• pp.279-285
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• 2019

Bio-based polyester polyols were synthesized using esterification with azelaic acid, sebacic acid, and 1,3-propanediol. Polyurethanes were prepared using chain extenders (1,4-Butanediol, 1,3-Propanediol, and isosorbide) and 4,4'-diphenylmethane diisocyanate with a mixing ratio of 1:1:1.1. Subsequently, the properties of the polymers prepared using the different chain extenders were compared. The synthesis of polyurethane was confirmed by FT-IR, TGA, and GPC. The mechanical properties (hardness, ball rebound, and tensile strength) of the materials were analyzed using shore A tester, taber abrasion, and UTM. heat, chemical, and water resistances of the prepared materials were measured by comparing the tensile strengths according to external changes.

• Applied Chemistry for Engineering
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• v.34 no.4
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• pp.434-443
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• 2023

We have investigated the performance improvement of grease by synthesizing calcium sulfonate grease as an alternative to lithium grease, which is widely used globally. Since the composition ratio of the grease, when manufactured, is usually 50% base oil and 50% thickener, using grease as a lubricant in a cryogenic environment is not encouraged due to its inferior low-temperature performance. In this study, we have synthesized three types of calcium sulfonate grease with paraffin oil and PAO-based base oil and thickener. Furthermore, lithium grease was synthesized via saponification with PAO-based base oil, lithium hydroxide, 12-hydroxystearic acid, and sebacic acid. We have measured low-temperature characteristics using a rheometer and low-temperature torque meter, and tribology characteristics were obtained using a four-ball lubricant tester and schwingung reibung verschleiß (SRV). As a result, the flow point of the calcium sulfonate grease synthesized with a PAO-based base oil and thickener was found to be -40℃, overcoming the existing calcium sulfonate grease's low-temperature limitation. Moreover, the synthesized calcium sulfonate grease showed low-temperature performance similar to that of lithium grease synthesized with PAO base oil, but superior anti-wear, extreme pressure, coefficient of friction, heat resistance, adhesion, and corrosion resistance. It is thus expected to commercially replace the existing lithium grease.

• Journal of Biomedical Engineering Research
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• v.19 no.5
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• pp.511-518
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• 1998

In order to develop the aerosol bolus technique which is thought to be a potential tool for probing geometries or abnormalities of small airways, an experimental system of measuring fast time variations of particle concentration in the inhaled and exhaled breathing air was developed. The system generates monodisperse sebacic acrid particles of 1 micron size and 1.2 of geometric standard deviation in high concentration of $10^8$ particles/cc, delivers a short pulse of particles at the controlled instant during inhalation using a solenoid valve, and measures the fast change of particle concentration in using the laser light scattering. Successful operation of the generator and the measuring system was confirmed by smooth concentration profiles in inhalation. It was also confirmed that maintaining a constant breathing rate is essential to stable outputs and any disturbance in flow rate near the mode (maximum concentration) induces a large number of spurious peaks in the exhalation. Experimental data without strict control of breathing flow rate showed a substantial amount of scatter. The measured results showed an improvement in scatter over the existing results. When compared with theoretical predictions from 1-D convective diffusion equation and other experiments, general characteristics of dispersion for several penetration depths showed a good agreement, but there exists some difference in absolute values, which is attributed to the difference in body conditions. Improvements are needed in the theory, especially in relation to correcting for the effect of breathing flow rate.