• Polymer(Korea)
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• v.24 no.1
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• pp.65-71
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• 2000

The latent properties and cure kinetics of an acid anhydride-cured epoxy resin have been investigated by a near-infrared (NIR) reflection spectroscopy. The assignments of the latent properties and cure behaviors were performed by the measurements of the NIR reflectance for epoxide and hydroxyl groups at different temperatures. A comprehensive analysis of the origin, location, and shifts during reaction of all major NIR absorption peaks in the spectral range from 4000 to 7100 $cm^{-1}$ / was provided. The extent of reaction was determined from NIR absorption band at the 4530 $cm^{-1}$ / depending on epoxide concentration and cure temperature.

• Proceedings of the KIEE Conference
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• 1988.07a
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• pp.343-345
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• 1988

In this paper the fabrication and application of Composite-Thermistor were studied. Composite-Thermistor specimens were made by conventional process. Some compounds of vanadium oxides and semiconductor oxides as a fillers were used to fabricate Composite-Thermistor, and Epoxy Resins are used as a polymer matrix. The results of resistivity-temperature characteristics were measured in the range from -100 ($^{\circ}C$) to 200($^{\circ}C$). The harder polymer, Eccogel series #1365-80 and Spurr Epoxy are more preferable compared to the Eccogel (1365-45) with some fillers.

• Proceedings of the KIEE Conference
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• 1997.07e
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• pp.1813-1815
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• 1997

In this study, in order to develop outdoor insulating materials, SIN(simultaneous interpenetrating polymer network) was introduced to Epoxy resin and the environment resistance was investigated. Six kinds of specimen were manufacture by filler($SiO_2$) content. SEM was untilized in order to confirm their network structure changes. Also, tracking test, UV test and acid rain test were carried out investigate the environment resistance characteristic. Therefore it was confirmed that simultaneous interpenetrating polymer network specimens were more excellent than single network structure specimens. But, acid rain almost never changed resistance.

• Macromolecular Research
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• v.10 no.1
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• pp.24-33
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• 2002

Interfacial and microfailure properties of carbon fiber/epoxy composites were evaluated using both tensile fragmentation and compressive Broutman tests. A monomeric and two polymeric coupling agents were applied via the electrodeposition (ED) and the dipping applications. A monomeric and a polymeric coupling agent showed significant and comparable improvements in interfacial shear strength (IFSS) compared to the untreated case under both tensile and compressive tests. Typical microfailure modes including cone-shaped fiber break, matrix cracking, and partial interlayer failure were observed under tension, whereas the diagonal slipped failure at both ends of the fractured fiber appeared under compression. Adsorption and shear displacement mechanisms at the interface were described in terms of electrical attraction and primary and secondary bonding forces.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2004.04a
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• pp.151-154
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• 2004

Despite of the excellent properties of carbon nanofiber, The properties of carbon nanofiber filled polymer composites were not increased largely. The reason is that it is still difficult to ensure the uniform dispersion of carbon nanofiber in a polymer matrix. In this study, For improvement properties of carbon nanofiber filled epoxy composites, the effect of dispersion was investigated. The compounds were prepared by two methods, solution blending and mechanical mixing. Mixing of solution blending method was used using ultrasonic. Dispersion of carbon nanofiber was observed by optical microscope and scanning electron microscope (SEM). UV adsorption and turbidity measured by UV spectrometer was used for the comparison of dispersion of carbon nanofiber.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2000.11a
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• pp.17-21
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• 2000

Logarithmic electrical resistivity of the untreated or thin diameter carbon fiber composite increased suddenly to the infinity when the fiber fracture occurred by tensile electro-micromechanical test, whereas that of the ED or thick fiber composite increased relatively broadly up to the infinity. Electrical resistance of single-carbon fiber composite increased suddenly due to electrical disconnection by the fiber fracture in tensile electro-micromechanical test, whereas that of SFC increased stepwise due to the occurrence of the partial electrical contact with increasing the buckling or overlapping in compressive test. Electrical resistivity measurement can be very useful technique to evaluate interfacial properties and to monitor curing behavior of single-carbon fiber/epoxy composite under tensile/compressive loading.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.207-208
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• 2007

Recently, high performance microelectronic devices are designed in multi-layer structure in order to make dense wiring of metal conductors in compact size. Imprint lithography have received significant attention due to an alternative technology for photolithography on such devices. In this work, we synthesized dielectric composite materials based on epoxy resin, and investigated their thermal stabilities and dynamic mechanical properties for thermal imprint lithography. In order to enhance the mechanical properties and toughness of dielectric material, various modified polyetherimide(PEI) was applied in the resin system. Curing behaviours, thermal stabilities, and dynamic mechanical properties of the dielectric materials cured with various conditions were studied using dynamic differential scanning calorimetry (DSC), thermo gravimetric analysis (TGA), and Universal Test Method (INSTRON).

• Korean Journal of Materials Research
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• v.15 no.1
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• pp.1-5
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• 2005

Copper-based leadframe sheets were immersed in two kinds of hot alkaline solutions to form brown-oxide or black-oxide layer on the surface. The oxide-coated leadframe sheets were molded with epoxy molding compound (EMC). After post mold curing, the oxide-coated EMC-leadframe joints were machined to form sandwiched double-cantilever beam (SDCB) specimens. The SDCB specimens were used to measure the fracture toughness of the EMC/leadframe interfaces under quasi-Mode I loading conditions. Fracture surfaces were analyzed by various equipment to investigate failure path. The present paper deals with the failure path, and the cause of the failure path formation with an adhesion model will be treated in the succeeding paper.

• Korean Journal of Materials Research
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• v.15 no.1
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• pp.6-13
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• 2005

Copper based leadframe sheets were immersed in two kinds of hot alkaline solutions to form brown-oxide or blackoxide layer on the surface. The oxide-coated leadframe sheets were molded with epoxy molding compound (EMC). After post mold curing, the oxide-coated EMC-leadframe joints were machined to form sandwiched double-cantilever beam (SDCB) specimens. The SDCB specimens were used to measure the fracture toughness of the EMC/leadframe interfaces under quasi-Mode I loading conditions. After fracture toughness testing, the fracture surface were analyzed by various equipment to investigate failure path. An adhesion model was suggested to explain the failure path formation. The adhesion model is based on the strengthening mechanism of fiber-reinforced composite. The present paper deals with the introduction of the adhesion model. The explanation of the failure path with the proposed adhesion model was introduced in the companion paper.

• Bulletin of the Korean Chemical Society
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• v.13 no.3
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• pp.274-279
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• 1992

Immobilization method of lariat azacrown ethers, containing hydroxyl group in the side arm of crown ring, on the polymer matrix and the phase-transfer catalytic activity of thus obtained immobilized lariat azacrown ethers were studied. Polystyrene resins with crown ether structures and hydroxyl groups adjacent to the macrorings were prepared by the reaction of crosslinked polystyrene resins containing epoxy groups with monoaza-15-crown-5 or monoaza-18-crown-6. Microporous crosslinked polystyrene resins containing epoxy group for the syntheses of these immobilized lariat crown catalysts were prepared by suspension polymerization of styrene, divinylbenzene (DVB 2%) and vinylbenzylglycidyl ether. The immobilized lariat catalysts with 10-20% ring substitution exhibited maximal activity for the halogen exchange reactions of 1-bromooctane with aqueous KI or NaI under triphase heterogeneous conditions. Immobilized catalyst exhibited higher activity than corresponding catalyst without the hydroxyl group and this result was suggested that the active site have a structure in which the $K^+$ ion was bound by the cooperative coordination of the crown ring donors and the hydroxyl group in the side arm.