• Title/Summary/Keyword: epoxy

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The Study of Water Stability of MDF Cement Composite by Addition of Epoxy Resin and Manufacturing Process (Epoxy Resin 첨가 및 제조공정에 따른 MDF 시멘트 복합재료의 수분안정성 연구)

  • 노준석;김태진;박춘근;최상홀
    • Journal of the Korean Ceramic Society
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    • v.35 no.4
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    • pp.371-377
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    • 1998
  • The effect of epoxy resin on the water stability of HAC/PVA based MDF cement composite were stu-died through the three different forming methods calendering extruding and warm pressing. In prexing step the epoxy resin was added in 5-15wt% of cement weight. The 3-point flexural strength of each dry and wet specimen which were immersed in water during 3. 7, 14 days was estmated and the mi-crostructural change of epoxy resin-added MDF cement composite due to water immersion was charac-terized by scanning electron microscopy. As the addition amount of epoxy resin the im-provement of water stability of MDF cement composite was achieved in most case. Especially through the warm press forming method the effectiveness of epoxy resin addition to the water stability was enhanced. When the epoxy resin was added by 5wt% to 7wt% the optimum flexural strength and water stability

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An Estimation of the Long-Term Properties of Epoxy Used for Reinforcing Surface in Concrete (콘크리트 표면강화 에폭시의 장기특성 평가)

  • 김성욱;김도겸;이장화;김근경;김상조
    • Proceedings of the Korea Concrete Institute Conference
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    • 1999.10a
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    • pp.183-186
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    • 1999
  • Up to date, it is difficult to estimate the consistence of properties on the epoxy liner in service time because an estimation of the long term environment-deterioration with aging has not been processed. In the study, the estimation on epoxy liner is carried by the physical test 7 rounds. There are the elongation the and the crack bridging test in the part of physical tests. An elongation test is carried out with epoxy membrane and a crack bridging test is carried out with specimen painted epoxy on concrete. The subjects of test and estimation are a containment quality system and a fibre-glass reinforced system. The materials of these systems are a Robber added Epoxy, a Silica added Epoxy, and a Fiber reinforced Epoxy. Ensuring the test data, properties of epoxy liner was estimated and the change of properties was predicted on epoxy liners.

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Synthesis of Epoxy Functional Siloxane and its Effect on Thermal Stress

  • Hyun, Dae-Sup;Jeong, Noh-Hee
    • Journal of the Korean Applied Science and Technology
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    • v.26 no.4
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    • pp.379-384
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    • 2009
  • Epoxy resin based encapsulants are widely used in semiconductor packaging applications. Epoxy resin based encapsulants are often subject to crack or delamination during the reliability test due to the thermal stress caused by high modulus nature of epoxy resins. Epoxy functional siloxanes are often added into epoxy resin to reduce the modulus so that the thermal stress can be reduced. Epoxy functional siloxanes, additives for reduced modulus, were synthesized and added into the curable epoxy resins. The modulus and the coefficient of thermal expansion (CTE) were also measured to investigate the thermal stress and to see whether the epoxy functional siloxane adversely affects the CTE or not. As a result, around 26% to 72% of thermal stress reduction was observed with no adverse effect on CTE.

Properties of Epoxy Modified PVC-sol Sealants (에폭시가 함유된 PVC졸 실란트의 물성)

  • Lee, Seung-Jin;Kim, Hyun-Kyo;Park, Hwan-Man;Cho, Won-Jei;Ha, Chang-Sik
    • Elastomers and Composites
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    • v.34 no.3
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    • pp.199-211
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    • 1999
  • In this work, the effects of the addition of epoxy on the properties of PVC-sol sealants were investigated. PVC-sol was plasticized with dioctyl phthalates(DOP). Two kinds of epoxy resins having different epoxy equivalent weight (E.E.W.) were used. It was found that the properties of the PVC-sol sealants were significantly affected by the contents and types of the added epoxy resins. The viscosity behaviors of the epoxy-modified sealants, in the case of epoxy A addition, the viscosity was decreased with increasing the epoxy contents, but In the case of $CaCO_3$ addition, the viscosity was increased with increasing the $CaCO_3$ contents. The viscosity of epoxy modified sealants aged at $45^{\circ}C$ waterbath was decreased with increasing epoxy contents, since the epoxy acted on the sealants as a stabilizer. The thermal stability of the PVC-sol sealants was slightly improved by adding epoxy. The tensile strength and elongation of sealants modified with epoxy A(two functionalities of epoxy) were increased with increasing the epoxy contents up to a certain epoxy contents but was decreased with further increasing the epoxy contents. In the case of $CaCO_3$ addition, the tensile strength of sealants were decreased with increasing the $CaCO_3$ contents. In view of the electrical properties, such as tan ${\delta}$($0.1{\pm}0.04$) and ${\epsilon}_r$($0.5{\pm}0.04$), it was found that the epoxy modified sealants were as good as insulators.

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The Toughness of Polyurethane and Epoxy Resins IPNs (폴리우레탄-에폭시 IPNs의 강인성)

  • Kim, Jong Seok;Hong, Suk Pyo
    • Applied Chemistry for Engineering
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    • v.9 no.3
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    • pp.445-450
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    • 1998
  • Interpenetrating polymer networks(IPNs) were prepared from castor oil-type polyurethanes(PUs) and epoxy resin. Two types of PU were prepared by using polypropylene ether glycol(PPG) as a chain extending agent and caster oil(CO) as a crosslinking agent. COPU/epoxy simultaneous interpenetrating polymer networks(SINs) based on CO had a better compatibility over the all composition than PPGPU/epoxy SINs based on PPG. The flexural strength of all PPGPU/epoxy SINs was decreased with decreasing entanglement of networks. COPU/epoxy SINs showed the higher fracture toughness and mechanial properties than the PPGPU/epoxy SINs. Fracture surfaces of all of the SINs showed the localized shear deformation and crack deflection rather than generation of stress whitening associated with the cavitation.

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Cure Properties of Isocyanurate Type Epoxy Resin Systems for FO-WLP (Fan Out-Wafer Level Package) Next Generation Semiconductor Packaging Materials (FO-WLP (Fan Out-Wafer Level Package) 차세대 반도체 Packaging용 Isocyanurate Type Epoxy Resin System의 경화특성연구)

  • Kim, Whan Gun
    • Journal of the Semiconductor & Display Technology
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    • v.18 no.1
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    • pp.65-69
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    • 2019
  • The cure properties of ethoxysilyl diglycidyl isocyanurate(Ethoxysilyl-DGIC) and ethylsilyl diglycidyl isocyanurate (Ethylsilyl-DGIC) epoxy resin systems with a phenol novolac hardener were investigated for anticipating fan out-wafer level package(FO-WLP) applications, comparing with ethoxysilyl diglycidyl ether of bisphenol-A(Ethoxysilyl-DGEBA) epoxy resin systems. The cure kinetics of these systems were analyzed by differential scanning calorimetry with an isothermal approach, and the kinetic parameters of all systems were reported in generalized kinetic equations with diffusion effects. The isocyanurate type epoxy resin systems represented the higher cure conversion rates comparing with bisphenol-A type epoxy resin systems. The Ethoxysilyl-DGIC epoxy resin system showed the highest cure conversion rates than Ethylsilyl-DGIC and Ethoxysilyl-DGEBA epoxy resin systems. It can be figured out by kinetic parameter analysis that the highest conversion rates of Ethoxysilyl-DGIC epoxy resin system are caused by higher collision frequency factor. However, the cure conversion rate increases of the Ethylsilyl-DGEBA comparing with Ethoxysilyl-DGEBA are due to the lower activation energy of Ethylsilyl-DGIC. These higher cure conversion rates in the isocyanurate type epoxy resin systems could be explained by the improvements of reaction molecule movements according to the compact structure of isocyanurate epoxy resin.

The Effects of a Chain Extending Agent and Crosslinking Agent on the Toughness of Castor Oil based Polyurethane-Epoxy IPNs (Castor Oil형 폴리우레탄-에폭시 IPNs에서 사슬연장제와 가교제의 영향에 의한 강인성)

  • Kim, Jong-Seok;Yang, Yeong-Seok
    • Applied Chemistry for Engineering
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    • v.10 no.5
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    • pp.639-643
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    • 1999
  • Interpenetrating polymer networks(IPNs) composed of castor oil(CO) polyurethane(PU) and epoxy resin were prepared by the simultaneous polymerization technique. Two types of PU were prepared using 1,4-butanediol(BD) and BD/trimethylolpropane(TMP) as a chain extending agent and crosslinking agent. The PU/epoxy based on BD as a chain extending agent showed more shift in the damping peak than PU/epoxy based on BD/TMP as the PU content was increased. BDPU/epoxy simultaneous interpenetrating polymer networks(SINs) had a better compatibility than BD/TMP-PU/epoxy SINs. For both systems, it was postulated that unique network formation of PU/epoxy SINs as a chain extending agent and crosslinking agent had occurred to a significant extent of phase mixing. The types of chain extender in the PU were found to be an important factor in determining the phase mixing of the IPNs. When the BD/TMP-PU reaction was faster than epoxy network, the extent of phase mixing was retarded by decreasing entanglement of networks. It was found that both PU/epoxy SINs provided enhanced flexural properties and fracture toughness, fracture surfaces of BDPU/epoxy and BD/TMP-PU/epoxy SINs showed the localized shear deformation and generation of stress whitening associated with the cavitation.

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Dielectric Properties of Epoxy/Micro-sized Alumina Composite and of Epoxy/Micro-sized/Nano-sized Alumina Composite

  • Park, Jae-Jun
    • Transactions on Electrical and Electronic Materials
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    • v.16 no.6
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    • pp.338-341
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    • 2015
  • Epoxy/micro-sized alumina composite was prepared, and the effects of alumina content on the dielectric properties were investigated in order to develop an insulation material for gas-insulated switchgears (GIS). Nano-sized alumina (average particle size: 30 nm) was also incorporated into the epoxy/micro-sized alumina composite. Dielectric tests were carried out in ASTM D 150, and capacitance (Cp) and dielectric loss (tanδ) were measured. The dielectric constant increased with increasing alumina content in the epoxy/micro-alumina system and the epoxy/micro-alumina/nano-alumina system. As 1,3-diglycidyl glyceryl ether (DGE) content increased, the dielectric constant decreased and dielectric loss increased. This ocurred as a result of the weak electric field enhancement due to homogeneous dispersion of micro- and nano-sized alumina particles in an epoxy composite.

Experimental Evaluation on Degradation Characteristics of Epoxy Coating by Using Adhesion Force and Impedance (부착력과 임피던스를 이용한 에폭시 도장재 열화 특성에 관한 실험적 평가)

  • Nah, Hwan-Seon;Kim, Noh-Yu;Kwon, Ki-Joo;Song, Young-Chol
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.7 no.2
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    • pp.149-157
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    • 2003
  • The purpose of this paper is to quantitatively investigate aging state of epoxy coating on containment structure at nuclear power plant. In order to evaluate an physical bonding of the epoxy coating, adhesion test was performed on a degraded epoxy coating on concrete specimens fabricated by accelerated aging experiment. In addition, impedance data by ultrasonic test were measured to compare with adhesion data. From almost 50 % of the specimens, aging phenomena of epoxy coating such as pin hole, blistering was discovered. To improve reliability on quality degradation of epoxy, co-relation between two kinds of different data was analyzed. By tracing co-related these data, it was possible to figure out physical state of as-built epoxy coating. The possibility to develop new methodology of time - dependent aging state on epoxy coating was found and discussed.

Study on Hygrothermal Degradation and Corrosion Protection of Epoxy Coatings Cured by Different Amine Based Curing Agents

  • Shon, Min-Young;Kwon, Huck-Sang
    • Corrosion Science and Technology
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    • v.9 no.5
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    • pp.201-208
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    • 2010
  • Epoxy coatings cured by different amine based curing agents have been prepared. Atomic force microscopy (AFM) has been used to monitor the surface topology changes of epoxy coatings before and after hygrothermal cyclic test. The glass transition temperature ($T_g$) and coefficient of thermal expansion (CTE) of the epoxy coating were measured by Thermo-mechanical Analysis (TMA). The Electrochemical impedance spectroscopy (EIS) with hygrothermal cyclic test has been introduced to evaluate the corrosion protection of the epoxy coatings. In conclusion, thermal properties of epoxy coatings were in good agreement with the results of corrosion protection of epoxy coated carbon steel obtained result by EIS with hygrothermal cyclic test. The relationship between thermal properties, surface roughness changes and corrosion protection of epoxy coatings are discussed in this study.