• Title, Summary, Keyword: epoxy

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The Modification of Epoxy Resins with Liquid Rubbers (Liquid Rubber를 이용한 Epoxy Resin의 개질)

  • Choi, Sei-Young;Kim, Young-Jun;Yun, Ju-Ho
    • Elastomers and Composites
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    • v.31 no.1
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    • pp.13-22
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    • 1996
  • In order to Improve the fracture toughness of epoxy resin system, liquid chloroprene rubber(LCR) and liquid butadiene rubber (LBR) which have hydroxy group were used in the brittle epoxy system. Mechanical and toughness characterization of the modified epoxy resins were investigated as a function of liquid rubbers content. Epoxy resins modified with both of the liquid rubbers showed complete phase-separation microstructure : In all of the LCR content, it was observed that the domain size of LCR dispersed in the epoxy matrix ranging from $2{\mu}m\;to\;5{\mu}m$. It was found that fracture toughness, $K_{ic}$, of the modified LCR system was enhanced continuously as increasing LCR content. However around 10phr of LBR system showed maximum fracture toughness. Specifically, when BPA add to the modified LCR system, thermal and mechanical properties increased than neat epoxy. At the same time, fracture toughness was enhanced.

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Performance of Epoxy Resins for Repairing of Cracks in Concrete with Application Conditions (콘크리트 균열 보수용 에폭시의 시공조건에 따른 성능)

  • Lee, Chan-Young;Shim, Jae-Won;Kim, Hong-Bae
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.813-816
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    • 2004
  • This study was performed to investigate bonding performance of epoxy resins for repairing of cracks in concrete, as a part of project to establish quality control standard for epoxy resins. In the slant shear strength test for hard and soft type epoxy, hard type was higher about 3 times than soft one. From the results, it is thought that hard type is suitable for load carrying. Injection of epoxy resin in the notch made flexural strength increase about $47\%$ over the specimen that epoxy resin is not injected. There were no differences in bonding performances with viscosity. Application of epoxy resin on the wet concrete surface made slant shear strength decrease about $46\%$, but similar performance to the case of application on the dry surface appeared by using epoxy resin for wet condition.

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A Study of CT Development Applied Elastic Epoxy (탄성형 에폭시를 사용한 변류기 개발에 관한 연구)

  • Lee, K.W.;Lee, K.Y.;Chang, Y.M.;Choi, Y.S.;Park, D.H.
    • Proceedings of the KIEE Conference
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    • pp.197-199
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    • 2004
  • In this paper, we studied a accuracy for CT using elastic epoxy. According to industry development, the quality where also the electric material is various is demanded. Insulation material is widely used because epoxy is superior to electrical and mechanical property. Until now, the possibility where the crack will occur is high because epoxy used to electrical products had high hardness. If thermal expansion is different of two material, contraction of epoxy heavily transformed turns ratio of CT. Elastic epoxy absorbed in expansion and contraction of substance material by temperature. So we could design more exacted CT. We had elastic test of elastic epoxy and made CT using elastic epoxy. At the result, We obtained turns ratio of within 4% superior to existing CT.

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Current Transformer Using Epoxy (에폭시를 사용한 변류기)

  • Park, Chul-Woong;Kim, Hyang-Kon
    • Proceedings of the KIEE Conference
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    • pp.199-202
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    • 2008
  • In this paper, we studied a accuracy for CT using elastic epoxy. According to industry development, the quality where also the electric material is various is demanded. Insulation material is widely used because epoxy is superior to electrical and mechanical property. Until now, the possibility where the crack will occur is high because epoxy used to electrical products had high hardness. If thermal expansion is different of two material, contraction of epoxy heavily transformed turns ratio of CT Elastic epoxy absorbed in expansion and contraction of substance material by temperature. So we could design more exacted CT We had elastic test of elastic epoxy and made CT using elastic epoxy. At the result, We obtained turns ratio of within 4% superior to existing CT.

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Effects of Surface Modification with Amino Terminated Polydimethylsiloxane(ATP) on the Corrosion Protection of Epoxy Coating

  • Shon, MinYoung
    • Corrosion Science and Technology
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    • v.8 no.3
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    • pp.103-109
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    • 2009
  • An epoxy coating was designed to give a hydrophobic property on its surface by modifying it with three types of Amino Terminated Polydimethylsiloxane (ATP), and then effects of the modification on the structure, surface hydrophobic tendency, water transport behavior and hence corrosion protectiveness of the modified epoxy coating were examined using FT-IR spectroscopy, hydrothermal cyclic test, and impedance test. The surface of epoxy coating was changed from hydrophilic to hydrophobic property due primarily to a phase separation tendency between epoxy and modifier by the modification. The phase separation tendency is more appreciable when modified by ATP with higher molecular weight ATP at higher content. Water transport behavior of the modified epoxy coating decreased more in that with higher hydrophobic surface property. The resistance to localized corrosion of the modified epoxy coated carbon steel was well agreed with its water transport behavior and hydrophobic tendency.

Investigation of Cure Kinetics and Storage Stability of the o-Cresol Novolac Epoxy Nanocomposites with Pre-intercalated Phenolic Hardeners

  • Hwang, Tae-Yong;Lee, Jae-Wook;Lee, Sang-Min;Nam, Gi-Joon
    • Macromolecular Research
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    • v.17 no.2
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    • pp.121-127
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    • 2009
  • The cure kinetics of the epoxy-layered, silicate nanocomposites were studied by differential scanning calorimetry under isothermal and dynamic conditions. The materials used in this study were o-cresol novolac epoxy resin and phenol novolac hardener, with organically modified layered silicates. Various kinetic parameters, including the reaction order, activation energy, and kinetic rate constants, were investigated, and the storage stability of the epoxy-layered silicate nanocomposites was measured. To synthesize the epoxy-layered silicate nanocomposites, the phenolic hardener underwent pre-intercalation by layered silicate. From the cure kinetics analyses, the organically modified layered silicate decreased the activation energy during cure reaction in the epoxy/phenolic hardener system. In addition, the storage stability of the nanocomposite with the pre-intercalated phenolic hardener was significantly increased compared to that of the nanocomposite with direct mixing of epoxy, phenolic hardener, and layered silicate. This was due to the protective effect of the reaction between onium ions and epoxide groups.

Effect of surface treatment of graphene nanoplatelets for improvement of thermal and electrical properties of epoxy composites

  • Kim, Minjae;Kim, Yeongseon;Baeck, Sung Hyeon;Shim, Sang Eun
    • Carbon letters
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    • v.16 no.1
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    • pp.34-40
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    • 2015
  • In this study, in order to improve the thermal and electrical properties of epoxy/graphene nanoplatelets (GNPs), surface modifications of GNPs are conducted using silane coupling agents. Three silane coupling agents, i.e. 2-(3,4-epoxycyclohexyl)-ethyltrimethoxysilane (ETMOS), 3-glycidoxypropyltriethoxysilane (GPTS), and 3-glycidoxypropyltrimethoxysilane (GPTMS), were used. Among theses, GPTMS exhibits the best modification performance for fabricating GNP-incorporated epoxy composites. The effect of the silanization is evaluated using transmission electron microscopy (TEM), scanning electron microscopy, thermogravimetric analysis, and energy dispersive X-ray spectroscopy. The electrical and thermal conductivities are characterized. The epoxy/silanized GNPs exhibits higher thermal and electrical properties than the epoxy/raw GNPs due to the improved dispersion state of the GNPs in the epoxy matrix. The TEM microphotographs and Turbiscan data demonstrate that the silane molecules grafted onto the GNP surface improve the GNP dispersion in the epoxy.

Effect of chemically reduced graphene oxide on epoxy nanocomposites for flexural behaviors

  • Lee, Seul-Yi;Chong, Mi-Hwa;Park, Mira;Kim, Hak-Yong;Park, Soo-Jin
    • Carbon letters
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    • v.15 no.1
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    • pp.67-70
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    • 2014
  • In this work, nanocomposites of epoxy resin and chemically reduced graphene oxide (RGO) were prepared by thermal curing process. X-ray diffractions confirmed the microstructural properties of RGO. Differential scanning calorimetry was used to evaluate the curing behaviors of RGO/epoxy nanocomposites with different RGO loading amounts. We investigated the effect of RGO loading amounts on the mechanical properties of the epoxy nanocomposites. It was found that the presence of RGO improved both flexural strength and modulus of the epoxy nanocomposites till the RGO loading reached 0.4 wt%, and then decreased. The optimum loading achieved about 24.5 and 25.7% improvements, respectively, compared to the neat-epoxy composites. The observed mechanical reinforcement might be an enhancement of mechanical interlocking between the epoxy matrix and RGO due to the unique planar structures.

A study on the fracture toughness of seawater-absorbed carbon nanotube/epoxy/basalt composites

  • Kim, Man Tae;Rhee, Kyong Yop;Kim, Hyun Ju;Jung, Dong Ho
    • Carbon letters
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    • v.14 no.3
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    • pp.190-192
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    • 2013
  • It has been demonstrated in a previous study that carbon nanotube (CNT)/epoxy/basalt composites produce better flexural properties than epoxy/basalt composites. In this study, mode I fracture tests were conducted using CNT/epoxy/basalt composites with and without seawater absorption in order to investigate the effect of the seawater absorption on the mode I fracture toughness ($G_{Ic}$) of the CNT/epoxy/basalt composites. The results demonstrated that the compliance of the seawater-absorbed specimen was larger than that of the dry specimen at the same crack length, while the opposite result was obtained for the fracture load. The $G_{Ic}$ value of the seawater-absorbed CNT/epoxy/basalt composites was approximately 20% lower than that of the dry CNT/epoxy/basalt composites.

The Effect of Thermal Decomposition of Epoxy Resin for a Variation of Hardener (에폭시수지의 경화제 변화량에 따르는 열분해 영향)

  • Park, Keun-Ho;Lee, Yong-Sook;Song, Ju-Yeong;Lee, Soo;Kim, Sung-Il
    • Journal of the Korean Applied Science and Technology
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    • v.24 no.4
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    • pp.393-398
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    • 2007
  • We investigated heat stability of epoxy resin products and epoxy resin according to the influence hardener. The heat flow which shows the degree of thermal decomposition of the epoxy resin product and epoxy resin measured by using the differential scanning calorimeter (DSC). As a result, we found that in the case of heat stability for epoxy resin as hardener was added, the ratio of one to one (epoxy resin : hardener) was the most suitable in air condition and nitrogen atmosphere.