• Korean Chemical Engineering Research
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• v.51 no.1
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• pp.144-150
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• 2013

The kinetics of the transesterification of dimethyl terephthalate (DMT) with ethylene glycol (EG) was studied in a batch reactor. Bishydroxyethyl terephthalate (BHET), which is poly(ethylene terephthalate) (PET) monomer, can be produced by the transesterification reaction. Zinc acetate was used as a catalyst. Previous kinetic studies was carried out in a semi-batch reactor where generated methanol was removed so that reverse reactions were not considered in the kinetic expressions, resulting in inaccuracy of the kinetic model. Mathematical models of a batch reactor for the tranesterification reaction were developed and used to characterize the reaction kinetics and the composition distribution of the reaction products. More accurate models than previous ones were obtained and found to have a good agreement between model predictions and experimental data. Effect of process variables on the esterification reaction was investigated based on the experimental and simulation results.

• Polymer(Korea)
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• v.35 no.2
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• pp.146-151
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• 2011

The physical properties of poly (ethylene 2,6-naphthalate) (PEN) copolymers were studied. PEN copolymers were synthesized successfully from the mixtures of ethylene glycol(EG), 1,3-propanediol (PD) and l,4-butanediol (BD) with 2,6-dimethyl naphthalene dicarboxylate. The results indicated that PEN copolymers showed an amorphous state when the content of BD(PD) in applied EG/BD(EG/PD) mixtures was less than 40% during the polycondensation. As a result, the lowering of thermal properties, orientation, and mechanical properties was found, however, the dimensional stability was improved. This is a promising result to apply the synthesized PEN copolymers as flexibles substrates.

• Textile Coloration and Finishing
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• v.2 no.4
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• pp.223-230
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• 1990

This study was carried out with the view of fundamental investigating to improve the tactile and the hygroscopicity of Poly (ethylene terephthalate) (PET) fibers. Mono-sodium ethylene glycolate in ethylene glycol (MSEG-EG) solution was prepared and PET films were treated with it. The following conclusions were obtained. 1. The tensile strength decreased with increasing decomposition ratio while density, crystallinity and crystallite size increased with increasing decomposition ratio when PET films were treated with MSEG-EG solution. 2. Number of carboxyl end groups was increased until 10-20% decomposition ratio when PET films were treated with MSEG-EG solution. However, the decomposition ratio became more than 20%, the number of carboxyl end groups had tendency to decreased. 3. The surface tension of PET films increased for treating with MSEC-EG solution. Hydrogen bonding force and poler force among the components of surface tension increased while dispersion force among those decreased. 4. The moisture region of PET films increased with increasing decomposition ratio when PET films were treated with MSEG-EG solution.

• Applied Chemistry for Engineering
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• v.28 no.4
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• pp.485-489
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• 2017

Polyethylene terephthalate (PET) has been widely applied in polymers and packaging industries to produce synthetic fibers, films, drink bottles or food containers. Therefore, it has become one of the major plastic wastes. In this article, glycolysis known as one of the main methods in PET chemical recycling was investigated using a glycol to break down the polymer into a monomer. Glycolysis of PET and ethylene glycol was performed in a micro-tubing reactor under various conditions. The effect of glycolysis conditions on the product distribution was investigated at experimental conditions of the EG/PET ratio of 1~4, the reaction time of 15~90 min and the reaction temperature of $250{\sim}325^{\circ}C$ with Mn and Cu catalysts. The highest yield of bis (2-hydroxyethyl) terephthalate monomer (BHET) was obtained as 89.46 wt% under the condition of the reaction temperature of $300^{\circ}C$ and the time of 30 min using 10 wt% $Cu/{\gamma}-Al_2O_3$ catalyst, with the PET and ethylene glycol ratio of 1 : 2.

• Reproductive and Developmental Biology
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• v.39 no.3
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• pp.77-81
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• 2015

This study was carried out to evaluate the effects of embryonic stage and toxicities of cryoprotectant on the rates of survival and development of the cryopreserved mouse early embryo and finally to establish the cryopreservation method of surplus embryos obtained during assisted reproductive technology. Toxicities of two cryoprotectants, dimethyl sulfoxide (DMSO) and ethylene glycol (EG) were investigated using a murine embryo model. Female F-1 mice were stimulated with gonadotropin, induced ovulation with hCG and mated. Two cell embryos were collected and cultured after exposure to either DMSO or EG. Embryo development was evaluated up to the blastocyst stage. The total cell count of blastocysts that were treated with DMSO ($68.1{\pm}24.1$) at the 2-cell stage was significantly lower than that were treated with EG ($81.2{\pm}27.0$) or the control ($99.0{\pm}18.3$) (p<0.001). On comparison of two cryoprotectant treated groups, the DMSO treated group showed a decreased cell count compared with the EG treated group (p<0.05). Both DMSO ($15.4{\pm}1.5$) and EG ($10.2{\pm}1.4$) treated groups showed higher apoptosis rates of cells in the blastocyst compared with the control ($6.1{\pm}0.9$, p<0.0001). In addition, the DMSO treated group showed more apoptotic cells than the EG treated group (p<0.001). The potential toxicity of cryoprotectants was uncovered by prolonged exposure of murine embryos to either DMSO or EG at room temperature. When comparing two cryoprotective agents, EG appeared to be less toxic than DMSO at least in a murine embryo model.

• Fibers and Polymers
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• v.1 no.1
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• pp.6-11
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• 2000

In the polycondensation reaction of polyethyleneterephthalate(PET), $Sb_2$$O_3$, can react effectively as a catalyst, if physically transformed. $Sb_2$$O_3$ powder is transformed into liquid solution by dissolving in ethylene glycol(EG). Homogeneous catalyst is made by mixing this liquid solution with glycols having different solubility. The efficient reaction of PET polymerization is expected by using homogeneous catalyst. PET was synthesized using homogeneous catalysts of 4 wt.% $Sb_2$$O_3$ solution dissolved in glycol[EG, 2,2-bis(4-(2-hydroxyethoxy)phenol)propane(BHPP), neopentyl glycol(NPO), and 1,3-propandiol(PD)]. PET using EG-BHPP($Sb_2$$O_3$) catalysts shows the highest I.V. within a reaction time of 120 min. In the p-d analysis, PET using EG-BHPP($Sb_2$$O_3$) catalysts has the fastest propagation rate and slowest degradation rate. EG-BHPP($Sb_2$$O_3$) catalysts are more efficient than EG($Sb_2$$O_3$) catalysts and $Sb_2$$O_3$ powder catalysts.

• Korean Journal of Poultry Science
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• v.40 no.3
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• pp.197-205
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• 2013

This study established a method for preserving chicken primordial germ cells (PGCs) that enables long-term storage in liquid nitrogen ($LN_2$) for preservation of the species. The purpose of this study was to compare the effects of Ethylene Glycol (EG) and Propylene Glycol (PG) on viability of cryopreserved PGCs with vitrification in Korean Native Chicken (Ogye), and to fine should be find or to the optimal protocol for PGCs freezing. One of the important components of cryopreservation process is cryopreservation medium that plays a vital role in preventing cellular injury during freeze-thawing. Cryoprotective agents have been known to improve cell viability after freeze-thawing. PGCs obtained from the germinal gonade of 5.5~6 day (stage 28) chick embryos, using the MACS method were suspended in a freezing medium containing a freezing and protecting agents. Gonads were harvested from stage 28 chick embryos and pooled in groups of 10E embryos, contributing gonads to the cell suspension. The gonadal cells, including PGCs, were then frozen in 1 of the following cryoprotectant treatments: 2.5% EG, 5% EG, 10% EG, 2.5% PG, 5% PG, 10% PG, and 0% cryoprotectant as a control. Effects of exposure to vitrification solution and vitrification, with different concentrations of the cryoprotectant solution, were examined. After freezing and thawing, survival rates of the frozen-thawed PGCs from the 0, 2.5, 5, 10 and 15% EG plus FBS treatment were 44.24%, 64.51%, 85.63%, 80.51% and 73.52% (p<0.05), respectively. The viability of PGCs after freeze-thawing was significantly higher for 10% EG plus FBS treatment than for 10% PG + FBS treatment (p<0.05)(85.63% vs 66.81%). Therefore, these systems may contribute in the improvement of cryopreservation for a scarce species in birds preservation. This study established a method for preserving chicken PGC that enables systematic storage and labeling of cryopreserved PGCs in liquid N at a germplasm repository and ease of entry into a database. In the future, the importance for this new technology is that poultry lines can be conserved while work is being conducted on improving the production of germline chimeras.

• Proceedings of the Korean Fiber Society Conference
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• 2003.10b
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• pp.167-168
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• 2003

Dimethyl-2,6-naphthalenedicarboxylate(2,6-NDC)와 ethylene glycol(EG)로부터 유도되는 폴리에틸렌 나프탈레이트(PEN)는 폴리에틸렌 테레프탈레이트(PET)보다 열적 및 기계적 특성이 우수한 열가소성 고분자이며[1-2], 폴리에틸렌 글리콜(PEG)은 diol기를 함유한 친수성 고분자로서 의약품 및 기타 가공제로 널리 쓰이는 물질이다. 이미 PET는 이러한 PEC를 PET 합성과정에서 공단량체로 사용해 공중합시킴으로서 친수성을 갖는 PET로 개질하고자 하는 연구[3-4]가 다수 보고되어 왔으나, PEN의 경유는 아직 이에 관한 연구보고가 없는 실정이다. (중략)

• Journal of Environmental Health Sciences
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• v.23 no.3
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• pp.85-90
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• 1997

The objective of this study was to investigate biodegradation of TPA(terephthalic acid) and EG (ethylene glycol), treatment efficiency of polyester weight loss wastewater and microbial characteristics by aerated submerged biolfilm(ASB) p.rocess. In a batch reactor, pH increased from 7.0 to 8. 5 in the biodegradation of TPA. Whereas, in case of EG, decreased from 7.0 to 5.2. COD concentration rapidly decreased within 24hr in the biodegradation of TPA and EG. COD removal velocity constant(k) were 0.065-0.088 hr$^{-1}$. The biodegradation velocity of TPA was 1.4 times faster than that of EG. The ratio of suspended biomass to the total biomass in the reactor was 18.3-33.3%, increased as a high ratio of EG content. Biofilm thickness, biofilm dry density and attached biomass were 346-432 $\mu$m, 41.8-61.9 mg/cm$^3$, 1.45-2.67 mg/cm$^2$, respectively. There values increased as a high ratio of TPA content. In the hydraulic retention time of 36 hr, organic loading rate of 4 kgCOD/m$^3\cdot$ day and packing ratio of 70%, the effluent concentrations of TCOD, SCOD in a continuous flow reator were 1,388 mg/l, 147 mg/l and removal efficiencies were 77%, 97.6%, respectively.

• Journal of Veterinary Clinics
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• v.34 no.2
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• pp.156-160
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• 2017

We investigated the effect of ethylene glycol and antioxidants such as taurine, hypotaurine and trehalose with extenders during cryopreservation of Korean Jeju Black Bull spermatozoa. The cryopreservation of freshly collected spermatozoa was conducted with four different conditions. As a control, spermatozoa were cryopreserved with Tris egg-yolk extenders added 5% ethylene glycol (EG). Taurine (20 mM), hypotaurine (20 mM) and trehalose (20 mM) were individually added into tris egg-yolk extenders with 5% EG. After thawing of frozen spermatozoa with four different conditions, sperm viability, motility, acrosomal integrity, and membrane integrity were investigated. The significant (p < 0.05) improvement of sperm viability showed in all antioxidant treated thawed spermatozoa (taurine; $68.1%{\pm}4.4$, hypotaurine; $69.2%{\pm}6.7$ and trehalose; $68.0%{\pm}4.4$) when compared to control ($63.4%{\pm}5.6$). Neither positive nor detrimental effects of three antioxidants were shown sperm motility after thawing. The results of hypo-osmotic swelling test showed that the membrane integrity of taurine, hypotaurine or trehalose treated thawed spermatozoa ($64.1%{\pm}5.4$, $61.5%{\pm}3.7$ and $59.0%{\pm}4.0$, respectively) had significantly (p < 0.05) higher rate of the swollen sperm compared to control ($53.7%{\pm}9.7$). Hypotaurine treated frozen-thawed spermatozoa had siginificantly higher (p < 0.05) F pattern ratio than taurine, trehalose and control treated frozen-thawed spermatozoa. Trehalose added frozen-thawed spermatozoa had significantly higher (p < 0.05) acrosome reaction pattern ratio than taurine and hypotaurine added frozen-thawd spermatozoa. In this study, we found that antioxidants such taurine, hypotaurine and trehalose treatments during cryopreservation process could reduce damage of spermatozoa of Korean Jeju Black Bull and improved sperm capability of fertilization.