• Journal of the Korean Ceramic Society
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• v.38 no.8
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• pp.755-760
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• 2001

본 연구에서는 카본전극의 표면개질에 따른 리튬이온 전지의 전지특성 변화에 대해서 연구하였다. 즉, mesocarbon microbeads(MCMB) 카본에 에폭시 수지(resin)를 코팅시킴으로서 카본전극 표면에 개질시켰으며, 이에 따른 전극의 전기화학적 특성을 고찰하였다. 에폭시 수지에 의한 카본의 표면코팅은 30%의 H$_2$SO$_4$용액에서 2시간 동안 refluxing한 MCMB를 에폭시 수지를 용해시킨 THF(tetrahydrofuran) 용액에 넣어 혼합함으로써 MCMB 표면에 에폭시 수지가 코팅되도록 하였다. 이렇게 에폭시 수지가 코팅된 MCMB를 약 1000-130$0^{\circ}C$로 열처리하여 고분해능 투과전자현미경으로 관찰한 결과, 코팅층은 비정질 카본 구조를 갖게됨을 알 수 있었다. 또한, 에폭시 수지에 의하여 코팅된 MCMB는 코팅되지 않은 MCMB보다 더 높은 BET 비표면적을 나타내었다. Li/MCMB 전지 cell을 만들어 충방전시험을 수행한 결과, 에폭시 수지에 의하여 코팅된 MCMB로 만든 전극이 더 우수한 충방전 용량과 싸이클 특성을 나타내었다. 에폭시 수지 코팅으로 전극 표면을 개질시킴으로서 전지특성이 개선된 원인에 관하여 에폭시 코팅의 결정구조와 전극계면에서의 부동태 피막(passivation film) 형성과 연계하여 논의하였다.

• Proceedings of the Korea Concrete Institute Conference
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• 1993.10a
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• pp.79-84
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• 1993

철근의 부식은 철근 콘크리트 구조물에 있어서 심각한 열화현상을 유발할 수 있으며 최근 들어 이로 인한 피해가 많이 보고되고 있다. 이와 같은 부식의 억제방안 중 철근에 직접 에폭시를 도막하는 것이 가장 효과적인 것으로 알려져 있다. 그러나 이 경우 에폭시 도막에 따른 부착성능의 저하가 우려되는 바 본 연구는 철근부식방지를 위해 에폭시를 도막한 철근의 부착특성을 고찰하기 위해 수행되었다. 주된 변수는 콘크리트 압축강도, 부착길이, 에폭시 도막두께이며 각 변수별로 부착특성의 변화를 관찰하였고 이를 통해 에폭시도막 철근의 사용성을 검토하였다. 본 실험결과에 기초하여 부착강도 예측식을 제안하였고 실험결과와 예측치를 비교하였다.

• Proceedings of the Korean Society For Composite Materials Conference
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• 1999.11a
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• pp.172-176
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• 1999

에폭시 수지의 강인성 향상을 위하여 양말단에 아민 반응기를 가지는 PES-CTBN-PES triblock copolymer를 합성하여 이를 에폭시 수지의 강인화제로 사용하였으며 경화제로는 p-DDS(p-dichlorodiphenylsulfone)를 사용하였다. 또한 공중합체에 의한 물성 향상효과를 CTBN과 PES-NH$_2$의 블렌드에 의한 경우와 비교하였다. 강인화된 에폭시 수지의 물성은 강인성 및 굴곡특성을 측정하여 분석하였으며, 열특성은 DSC, TGA, 및 DMA에 의해 실시되었다. 그리고 강인화된 에폭시 수지의 강인성 향상 mechanism을 규명하기 위하여 파단면을 SEM으로 분석하여 상분리 거동을 고찰하였다. 높은 유리전이온도와 우수한 기계적 물성을 가지는 고성능 기능성 폴리설폰(PES-NH$_2$)과 상용 액상 고무 첨가제인 CTBN을 이용하여 합성된 공중합체를 강인화제로 사용함으로써 열안정성, 탄성률 및 내식성의 감소없이 에폭시 수지의 쳐대 단점인 강인성을 최적 수준으로 개선시킬 수 있었으며 공중합체의 에폭시 수지에 대한 우수한 용해도에 따른 가공성이 향상되었다.

• International Journal of Highway Engineering
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• v.14 no.1
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• pp.17-24
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• 2012

This study evaluated the performance of Korean epoxy asphalt mixtures using several laboratory tests. Four types of epoxy asphalt mixtures were manufactured based on 13mm dense graded asphalt mixtures: three Korean and one Japanese epoxy asphalt mixtures where 20% or 40% of asphalt binder was replaced by epoxy resins. Curing time was determined as 3 and 6 hours for the mixtures containing 40% and 20% of epoxy resins, respectively. From the laboratory tests including wheel tracking, indirect tension fatigue, bending beam, and moisture susceptibility tests, it was concluded that the epoxy asphalt mixtures had superior performance than conventional asphalt mixtures except moisture susceptibility. Also, the performance of the Korean epoxy asphalt mixtures was comparable to the Japanese mixtures. Thermal coefficient, bond strength, and indirect tension tests were conducted to examine the applicability of the Korean epoxy asphalt mixtures to concrete repair. Its adhesion was strong enough to be bonded to surrounding concrete materials and its tensile strength was comparable to the concrete, but thermal expansion coefficient was 5 times greater than the surrounding concrete.

• Journal of the Korean Society for Nondestructive Testing
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• v.36 no.3
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• pp.211-216
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• 2016

In several industrial fields, epoxy resin is widely used as an adhesive for co-curing and manufacturing various structures. Controlling the manufacturing process is required for ensuring robust bonding performance and the stability of the structures. A fiber optic sensor is suitable for the cure monitoring of epoxy resin owing to the thready shape of the sensor. In this paper, a fiber Bragg grating (FBG) sensor was applied for the cure monitoring of epoxy resin. Based on the experimental results, it was demonstrated that the FBG sensor can monitor the status of epoxy resin curing by measuring the strain caused by volume shrinkage and considering the compensation of temperature. In addition, two types of epoxy resin were used for the cure-monitoring; moreover, when compared to each other, it was found that the two types of epoxy had different cure-processes in terms of the change of strain during the curing. Therefore, the study proved that the FBG sensor is very profitable for the cure-monitoring of epoxy resin.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.2
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• pp.465-470
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• 2015

The curing of epoxy asphalt mixture depends on the chemical reaction of epoxy resin and the curing agent. The curing level of epoxy asphalt mixture needs to be predicted in order to decide traffic opening time and to establish further construction plans. In this study, chemical analysis of the prediction model was executed to expand the applicability of the previous prediction model. Consequently, the curing level prediction model of epoxy asphalt concrete mixture was proposed using the concentration ratio and the acid value ratio. According to the results of outdoor curing experiments, the final prediction model showed that the correlation coefficient is greater than 0.971. Precise prediction results of different composition epoxy asphalt were obtained by reflecting the chemical composition ratios in the curing level prediction model.

• Polymer(Korea)
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• v.35 no.1
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• pp.47-51
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• 2011

In this study, illite, an environmental friendly, low cost, and high aspect ratio additive, was used to improve flame retardant property of epoxy and it was fluorinated to enhance dispersion of hydrophilic illite in hydrophobic epoxy by introducing hydrophobic functional groups. Fluorination of illite enhanced illite dispersion ill epoxy solution before curing and that in the complex after curing. These enhanced dispersions were attributed to the increased affinity of illite to hydrophobic epoxy solution induced by fluorination of illite and the increased intercalation of epoxy polymer or exfoliation of illite by epoxy curing. Hence, limited oxygen index(LOI) of fluorinated illite/epoxy complex increased by 24%, compared to that of epoxy, suggesting that the preparation of fluorinated illite/epoxy complex increased their flame retardant properties.

• Elastomers and Composites
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• v.43 no.2
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• pp.113-123
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• 2008

Epoxy resins are thermoset polymers that exhibit good adhesion, creep resistance, heat resistance, and chemical resistance. These polymers, however, give poor resistance to crack propagation and low impact strength. In this study, epoxy/carboxyl-terminated butadiene acrylonitrile (CTBN) and epoxy/amine-terminated butadiene acrylonitrile (ATBN) composites were prepared with different ratio of CTBN and ATBN to improve low impact strength of epoxy resin. The impact strength of epoxy/elastomeric composites shows high values with increasting nonpolar surface free energy while the tensile strength and the glass transition are decreased. The highest surface free energy, impact strength observed when 15 phr CTBN and 15 phr ATBN added, respectively. It can be concluded that as liquid rubber to improve impact strength of epoxy resin, ATBN is more preferable to CTBN.

• Journal of Conservation Science
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• v.25 no.1
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• pp.77-86
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• 2009

The physical properties of the epoxy resins were studied with an addition of filler content and the application of artificial weathering test. When talc as a filler was added to the epoxy resin (L-30), the water resistance seemed to be increased because of the results of the reducing of water absorption rate and the increasing of contact angle. Although the adhesive strength of epoxy resins was not affected by the increasing amount of talc, its compressive strength was reduced. The physical properties of the epoxy resins had different trends according to the site environments. The artificial weathering test with the change of temperature and humidity showed that the changes of water absorption rate and colour differences of the epoxy resins containing talc were lower than the pure epoxy resin itself. However, the contact angle was higher. The artificial weathering test with ultraviolet irradiations showed the opposite result; the damage of epoxy resins was increased with the increasing of talc content. These mean the site environment of the stone monuments should be considered to determine the content of talc added to increase the durability of epoxy resin.

• Composites Research
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• v.27 no.4
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• pp.168-173
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• 2014

The optimum condition of glass fiber/epoxy composites was investigated according to mixing ratio of two epoxy matrices. Novolac type epoxy and isocyanate modified epoxy were used as composites matrix. Based on chemical composition of mixing matrix, optimum mixing ratio of epoxy resins was obtained through various experiments. In order to investigate thermal stability and interface of epoxy resin, glass transition temperature was observed by DSC instrument, and static contact angle was measured by reflecting microscope. Change of IR peak and $T_g$ was conformed according to different epoxy mixing ratio. After fabrication of glass fiber/epoxy composites, tensile, compression, and flexural properties were tested by UTM by room and high temperature. The composites exhibited best mechanical properties when epoxy mixing ratio was 1:1.