• Journal of the Korean Chemical Society
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• v.46 no.5
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• pp.444-456
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• 2002

To protect the occurrence of the oxidation of car body, we developed antioxidizing device made with sacrificial anode. Because car body is made of iron and iron-alloy and oxidation potential of Mg, Al and Zn is higher than that of iron, sacrificial anodes were made with Mg, Al and Zn. Accordingly, Mg, Al and Zn are better oxidizing than car body, iron and iron-alloy can be protected from oxidizing. We have made an antioxidizing device and evaluated their anti-corrosive effect for iron piece in the solution of hydrochloric, nitric and sulfuric acid using balance, SEM and XPS. When iron pieces were connected with antioxidizing device of car body, weight loss by oxidation was remarkably reduced and surface corrosion of iron piece was protected. It was shown that the surface of iron pieces which is not con-nected to the device was changed to iron(Ⅲ) oxide, Fe$_2$O$_3$. Therefore, if this device is attached to car body, corrosion and oxidation of car body will be reduced, considerably.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1996.04b
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• pp.113-116
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• 1996

기유의 soot 분산 성능 실험과 엔진유의 산화 및 분산성 실험을 하여 다음과 같은 결론을 얻었다. 1. 윤활기유는 soot의 분산 성능에 매우 큰 영향을 미치며 고급 기유일수록 soot의 함량이 클수록 우수한 성능을 보인다. 2. VHVI 기유는 산화 시험 시간이 경과할수록 광유계 기유보다 우수한 산화안정성을 나타낸다. 3. 산화방지제는 산화방지뿐 아니라 분산성에도 영향을 미친다. 4. 광유계 기유를 사용한 경우 ZnDDP는 산화 방지 및 분산성을 향상 시키지 못하나 VHVI 기유에 ZnDDP를 투여한 경우에는 산화방지효과와 분산성능을 향상시킨다.

• Korean Journal of Food Science and Technology
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• v.26 no.6
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• pp.690-695
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• 1994

The perilla seed and the germinated perilla seed $(25{\sim}28^{\circ}C$, $2{\sim}3\;days)$ were extracted by n-hexane, and from the extracted oil the antioxidative components were separated, and then the effect of the change in the contents of antioxidative components by germination on the oxidative stability of the perilla oil was studied. The perilla oils were solved acetone and methanol, and kept at $-60^{\circ}C$ overnight and separated into the frozen oil fraction and unfrozen solvent soluble fraction. By comparing the antioxidative stability of the frozen oil fraction the antioxidative components in the perilla oil were found to be methanol soluble. The methanol soluble fraction of perilla oil was applied to silica gel column chromatography and the separated fractions were compared in terms of antioxidative activity. The fraction of n-hexane : ethyl acetate (7 : 3, v/v) showing the highest antioxidative activity was further separated by TLC. The components included in the band $(R_f\;0.71)$ showing the highest antioxidative activity was separated by HPLC. Four peaks were observed on the HPLC chromatogram and the peak areas were changed by germination (perilla seed : peak 1; 46.5%, peak 2; 25.6%, peak 3; 22.6%, germinated perilla seed : peak 1; 43.8%, peak 2; 20.6%, peak 3; 29.8%). The comparative change in the contents of these components was considered to be one factor affecting the antioxidative stability of perilla oil by germination.

• Polymer(Korea)
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• v.37 no.2
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• pp.156-161
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• 2013

Phenolic antioxidants are effective stabilizers that provide excellent long-term heat stability by preventing thermo-oxidative degradation during processing and service life. However, under a selected set of circumstances, certain types of phenolics have been susceptible to discoloration due to prolonged storage in an environment containing oxides of nitrogen. It is investigated that the effect of addition of secondary antioxidant and chemical structure of primary antioxidant on discoloration of amorphous poly-${\alpha}$-olefin (APAO), which is especially prone to be decomposed in high processing temperature. From the result, it is concluded that a higher level of steric hindrance of phenolic antioxidant provided by long alkyl chain allows a more enhanced synergic effect with secondary antioxidant.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2015.11a
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• pp.285-286
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• 2015

반도체 패키지 솔더범프용 주석계 도금액에 적용 가능한, 친환경 산화방지제 몇 종에 대하여 연구하였다. 주석계 전기도금액에 포함된 산화방지제는 주석의 산화방지 외에도, 전류효율, 도금액의 안정성, 그리고 형성된 솔더범프의 특성 등에 영향이 있음을 확인 하였다.

• Korean Journal of Food Science and Technology
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• v.50 no.3
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• pp.286-291
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• 2018

This study aimed to investigate the antioxidant ability of a cumin seeds ethanol extract (CE). The DPPH and ABTS radical scavenging activities of 0.25, 0.5, and 1.0 mg/mL of CE were found to be 24.6, 41.4, and 73.4 and 14.5, 27.2, and 50.1%, respectively (p<0.05), suggesting a dose-dependent effect. Moreover, the total phenolic content of CE was $61.0{\mu}M$ tannic acid equivalent/g extract and the FRAP value was $429{\mu}M$ ascorbic acid equivalent/g extract. In 9 hours of oil oxidation, CDA and ${\rho}-AV$ was significantly reduced to 13.4 and 59.1%, respectively, at a CE concentration of 100 ppm compared with that in the control (p<0.05). Major volatile compounds of CE were found to be ${\alpha}$-pinene, 2-butenal, cyclohexene, ${\beta}$-pinene, cis-sabinene, ${\rho}$-cymene, and limonene. These results suggest that CE containing volatile compounds has excellent antioxidant ability and oxidation stability, and thus could be used as a natural antioxidant to prevent oxidation in lipid foods.

• Polymer(Korea)
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• v.26 no.4
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• pp.452-461
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• 2002

In this study, the effect of various concentrations of antioxidants on thermo-oxidative degradation of polyamide 6 was investigated. Unstabilized and stabilized polyamides 6 were subjected to long-term oven aging in ambient atmosphere at 70~$160^{\circ}C$. All of specimens were discolored within 100 hr at temperature range of 70~$160^{\circ}C$. Optimum antioxidant concentration was determined from the data of mechanical properties, yellowness index and relative viscosity. The synergistic effect of each primary and secondary antioxidant concentrations was not observed. Yellowing phenomenon was explained by using NMR, IR and EA. Different carbonyl groups were detected by $^{13}C$/NMR. During thermooxidative degradation, oxygen consumptions were determined by EA. The lifetime after long-term aging was predicted using Arrhenius equation.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.178.2-178.2
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• 2011

바이오디젤이란 식물성 기름, 동물성 지방, 폐식용유 등의 재생 가능한 자원을 촉매 존재 하에 알코올과 반응시켜 생성되는 에스테르 혼합물을 말하며 경유와 물성이 유사하므로 경유에 혼합하여 압축착화 방식인 디젤엔진에 사용할 수 있다. 그러나 바이오디젤은 경유에 비하여 탄소-탄소 간 이중결합을 가지고 있는 성분을 많이 함유하고 있기 때문에 공기에 의해 산화가 일어나기 쉽다. 일반적으로 폐놀계 향산화제인 t-buthylhydroquinone(TBHQ)를 사용하여 산화안정성을 향상시키나 국내에서 사용되는 산화방지제는 전량 수입에 의존하고 있어 제품 개발에 의한 국산화가 시급한 실정이다. 본 연구에서는 폐유지로부터 생산한 바이오디젤의 산화안정성 향상을 위하여 폐놀 및 아민계 등의 산화방지제를 합성하여 바이오디젤에 적용하였으며, 다양한 물성시험방법을 적용하여 석유 및 석유대체연료 사업법에서 규정하는 바이오디젤의 품질기준을 확인하였다. 또한 EN 14112 바이오디젤 산화안정성 시험방법으로 폐놀 및 아민계 등의 산화안정성을 확인하였다. 본 연구는 산학연 공동기술개발 1차년도 사업으로 한국화학연구원과 공동으로 수행하였으며, 산화방지제 적용평가를 통해 우수한 제품을 선정하여 2차년도에는 차량 테스트를 통해 연료 첨가제로서의 적합성을 검증할 예정이다.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2016.11a
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• pp.165.2-165.2
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• 2016

현재, 솔더범프용 주석계 도금액의 필수성분인 산화방지제의 경우, 국내외 경쟁사에서는 가격 및 성능이 우수한 벤젠/페놀 계열을 적용 중이다. 그러나, 최근 대형 고객사에서 페놀류 산화방지지제를 환경규제물질로 규정함에 따라, 자사에서는, 특허 이슈 해소 가능한 친환경 대체 산화방지제 개발을 해오고 있다. 본 연구에서는, 반도체 패키지용 주석계 도금액의 산화방지제 종류와 농도에 따른 주요 특성 (Particle, 전류 효율, 안정성 (변색, 침전 외), 범프 두께의 편차, 감광제의 침해, Reflow 후 빈공간 등)에 대하여 살펴보았다.

• Korean Journal of Food Science and Technology
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• v.23 no.4
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• pp.433-436
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• 1991

Natural compounds which could improve the oxidative stability of fish oil was screened from spices, herbs and naturally occurring antioxidants. Induction period of fish oil determined from oxidation curve by Rancimat ($80^{\circ}C$) was hardly affected with the addition of water-soluble and lipid-soluble fractions of garlic, leek, sesame leave and orange peel, and of organic acids such as citric acid, EDTA and selenium. Caffeic acid, catechin, quercetin and gallic acid laurylester, however, could extend the induction periods by $2.2{\sim}3.8$ times with the addition level of 0.1%(w/w). Rosemary extract and sesamol have a marked effect in retarding oxidation of fish oil. For example, induction periods of the oil samples stabilized with 0.1 rosemary extract and 0.1 sesamol were 16.4 hr and 11.6 hr, respectively, as compared to 4.0 hr of a control. When rosemary extract was used in combination with ascorbic acid (0.02%) or 8-tocopherol (0.2%), induction period could be extended to ca. 28 hr due to the synergism.