• Proceedings of the Korean Society of Veterinary Clinics Conference
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• 2006.11a
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• pp.97-97
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• 2006

• 월간산업보건
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• s.387
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• pp.21-25
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• 2020

소변에서 2-에톡시 아세트산(EAA)의 존재는 2-에톡시 에탄올이나 2-에톡시에틸 아세테이트의 노출이 있었다는 특정 지표가 된다. 2-에톡시 아세트산은 2-에톡시 에탄올 또는 2-에톡시에틸 아세테이트에 노출되지 않은 사람의 생물학적 시료에서는 존재하지 않는다. 생물학적 노출지표(Biologial Exposure Index, BEI)는 주중 마지막 교대가 끝날 때 채취한 소변의 2-에톡시 아세트산 측정으로 권고하고 있다. 측정치는 주중 누적 노출의 지표이다. 작업환경 노출의 주요 흡수 경로인 피부 흡수는 2-에톡시 아세트산의 소변 농도를 크게 증가시킨다.

• Journal of the Korean Chemical Society
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• v.32 no.3
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• pp.276-284
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• 1988

The crystallization behaviours of poly(ethylene terephthalate) modified by 1, 3-propane diol, 1, 5-pentane diol, 1, 6-hexane diol, or poly(ethylene glycol) of molecular weight 300 as a third component were studied by isothermal and nonisothermal crystallization. When the content of the third diol was about 4 mol %, the isothermal crystallization rate at the same supercooling below the melting temperature and the nonisothermal crystallization rate at the same overheating above the glass transition temperature were increased more by the shorter flexible diol unit. On the contrary the nonisothermal crystallization rate at the same supercooling below the melting temperature was increased more by the longer flexible diol unit.

• Journal of the Korean Institute of Gas
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• v.20 no.2
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• pp.16-22
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• 2016

Auto ignition characteristic is an important factor for handling combustible substance and fire prevention. This research studied about auto ignition characteristic and activation energy of Ethylene Glycol (EG) and Diethylene Glycol (DEG) by using ASTM D2155 type ignition temperature measuring apparatus. As the auto ignition temperatures, it was possible to get $434^{\circ}C$ for EG within sample amount range of $75{\sim}160{\mu}l$ and $387^{\circ}C$ for DEG within sample amount range of $130{\sim}150{\mu}l$. Also, it was possible to get $579^{\circ}C$ and $569^{\circ}C$ as instantaneous ignition temperatures with sample amount of $140{\mu}l$ for EG and DEG respectively. By using least square method from Semenov equation on measured ignition temperature and ignition delay time from this study, it was possible to calculate activation energy of EG as 25.41 Kcal/mol and DEG as 14.07 Kcal/mol. Therefore, it was possible to claim that DEG has more risk of auto ignition since the auto ignition temperature, instantaneous ignition temperature and activation energy of DEG is lower than EG.

• Journal of the korean veterinary medical association
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• v.22 no.11
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• pp.685-690
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• 1986

• KSBB Journal
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• v.26 no.3
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• pp.193-198
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• 2011

Polyester was prepared through the esterification reaction between watsepaper liquefied by ethylene glycol and carboxylic acid. Liquefaction was carried out at the previously determined condition of 100 minutes, $160^{\circ}C$, and 3% sulfuric acid, and the hydroxyl value of the liquefied product was 411 mg KOH/g. In order to remove bubbles produced during the curing step, the method to introduce a slight nitrogen stream into reaction vessel and/or the method to preheat a polyester film at $85^{\circ}C$ before curing step were used alone or in combination. But if curing temperature was $130^{\circ}C$, simple method to cure a film for 5 hours at $130^{\circ}C$ without using both methods was found to be most effective. The polyesters prepared with various carboxylic acids showed significant different physical properties, and maleic acid was best among them. Also, the effect of reaction time and temperature, C/H (carboxyl group/hydroxyl group) ratio, and type of additive on the crosslinkage of polyester was investigated. Lithium hydroxide or citric acid as additive was used to enhance the crosslinkage of polyester and citric acid was proved to be much more effective than lithium hydroxide. The effect of reaction temperature on the crosslinkage was marginal, but the crosslinkage decreased above $130^{\circ}C$. The crosslinkage was 86% when the polyester was prepared at an optimum condition such as $130^{\circ}C$ and 15 minutes of reaction condition, 1.5 of C/H ratio, $130^{\circ}C$ and 5 hours of curing condition, and 10% addition of citric acid.

• KSBB Journal
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• v.25 no.3
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• pp.251-256
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• 2010

A novel method to prepare polyester from wastepaper through liquefaction and crosslinking stages was studied. At the first stage, the liquefaction of wastepaper was carried out in the presence of ethylene glycol under acidic conditions. The factors that affect on liquefaction yield were found to be reaction time, temperature, and acid concentration, and their ranges were 60~120 minutes, $150{\sim}170^{\circ}C$, and 2~4%, respectively. The optimum condition was found to be 100 minutes, $160^{\circ}C$, and 3% sulfuric acid concentration, and the liquefaction yield at this condition was 67%. At the second stage, polyester was prepared from the liquefied wastepaper obtained at the optimum liquefaction condition by crosslinking with succinic anhydride. The effect of reaction time and carboxylic group/hydroxyl group ratio on crosslinkage were investigated at conditions covering 30~50 minutes of reaction time and 1.5~2.5 of carboxylic group/hydroxyl group ratio. The crosslinkages of polyester prepared were 80~90%, which were almost same regardless of reaction conditions.

• Polymer(Korea)
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• v.31 no.6
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• pp.550-554
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• 2007

Atom transfer radical polymerization (ATRP) has been widely used in bioconjugation as it is an efficient and facile method to prepare polymers with pre-designed structures. Quite often, bioconjugation with proteins employs primary amines in proteins as a functional group to attach an initiator. When 2-bromoisobutryl bromide, the most widely used precursor for ATRP initiator, is used, ${\alpha}-halo$ amide initiating groups are formed in the proteins, which are known to exhibit slow initiation behavior in the ATRP process. Here we studied the ATRP of [poly(ethylene glycol)methyl ether] methacrylate (PEGMA) using amide-based initiator. PEGMA differs for both the nature and size of the polymer side branches and shows good solubility in water and a property that made it an ideal candidate for biomaterials. While normal ATRP produced ill-defined p(PEGMA) with amide based initiators, the halogen exchange method and the external additional of deactivator effectively improved the control of ATRP of PEGMA.

• Korean Chemical Engineering Research
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• v.43 no.5
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• pp.603-608
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• 2005

The molded macroporous poly (glycidyl methacrylate-co-ethylene glycol dimethacrylate) rods produced by a facile molding process were polymerized in situ within a tubular mold, chromatographic column ($4.6{\times}100mm$) by free radical polymerization. It was complemented by epoxy derivatized monolithic column and chemical modification of the epoxide groups with the sulphuric acid. By variation of the polymerization conditions, such as the ratio of the monomers, the porogen (pore generating material), and the temperature, the pore size could be varied, so the retention time of the samples may be adjusted. For the mixture of caffeine and tryptophan in the prepared monolithic column, the influences of polymerization material compositions to the efficiency, selectivity, and resolution of the monolithic column were investigated.

• Clean Technology
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• v.17 no.3
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• pp.244-249
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• 2011

We synthesized low molecular-weight polymers bearing hydrophobic and hydrophilic parts in a chain through $CO_2$/propylene oxide copolymerization. When hydrophilic poly (ethylene glycol) bearing -OH group (s) at the end group (s) was added as a chain transfer agent in the $CO_2$/propylene oxide copolymerization catalyzed by a highly active catalyst, block polymers were formed. If poly (ethylene glycol) (PEG) bearing -OH group only at an end was fed, PEG-block-PPC diblock copolymer was obtained. When PEG bearing -OH group at both ends was fed, PPC-block-PEG-block-PPC triblock copolymer was obtained. We confirmed formation of block copolymers by $^1H$-NMR spectroscopy and GPC studies.