• Applied Chemistry for Engineering
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• v.5 no.6
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• pp.981-989
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• 1994

For the development of new material used bentonite in ceramic/organic material composite, ABS(acrylonitrile-butadiene-styrene) material was used as a matrix polymer and a series of bentonite was blended together. This bentonite, filler like talc or mica for plastic material, was used since natural bentonite(Ca type) is easily obtainable in Korea, Na-bentonite changed from natural bentonite by $Na_2CO_3$ based on the specified compositions, changes in the static and dynamic mechanical properties. It was discovered that the increased content of natural and Na- bentonite results in higher modulus with reduced impact strength. And Rockwell hardness was constant. And Na- bentonite filled polymer showed improvement in impact strength and lower in modulus as the natural bentonite filled polymer. The storage modulus(E') of Na- bentonite filled ABS resin was higher than that of Ca- bentonite filled ABS resin, while higher temperature, storage modulus(E') decreased. At higher frequency, tan ${\delta}$ peak was shifted at high temperature.

• Polymer(Korea)
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• v.25 no.3
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• pp.435-440
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• 2001

The objective of this study was to examine the effect of oxidation inhibitor contents on the work of adhesion, fracture toughness, and impact strength of the unidirectional carbon-carbon composites (C/C composites). The molybdenum disilicide ($MoSi_2$) used as an oxidation inhibitor was impregnated with phenolic resins to improve the anti-oxidation properties of the composites in different concentrations of 4, 12 and 20 wt%. Based on Wilhelmy equation, the work of adhesion of C/C composites was calculated by contact angle methods. Fracture toughness and impact strength were pressured by three-point bending test for the critical intensity factor ($K_IC$) and Izod test method, respectively. As a result, the composites made with $MoSi_2$ resulted in an increasing of both fracture toughness and impact strength. Especially, the composites made with 12 wt% $MoSi_2$ content showed the highest value of London dispersive component, $W_A\;^L$, in work of adhesion, resulting from improving the interfacial adhesion force among fibers, filler, and matrix in this system.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.2 no.2
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• pp.11-18
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• 1982

The binder for hot mix type colored pavement must have the same physical qualities as the straight asphalt cement, but its color must not be dark-brown. We developed a kind of synthetic resin binder with light yellow color and confirmed its possibility as a binder for colored pavement through the several comparison tests between the straight asphalt cement concrete mixture and the mixture of binder and aggregate for colored pavement. For the pigment, it has been assured through tests that home products have the possiblities to be used. The binder has come to the stage of practical use through the trial mixing by asphalt mixing plant and the trial field placing. The mixing operation and the paving method of colored mixture are same as normal asphalt concrete mixture, but the quantity of pigment replaces that of mineral filler. The required content of pigment is decided by the trial mixing with other materials to be used.

• Journal of Power System Engineering
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• v.15 no.6
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• pp.67-72
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• 2011

In the present study, crack healing effect and residual stress of $Al_2O_3$ ceramics were investigated by changing the sintering temperature and heat treatment conditions. And also it was investigated that the influence of different filler loadings of nano-sized SiC particles on the crack healing behavior of $Al_2O_3$ ceramics. The test samples were characterized by three point bend flexural tests to evaluate their mechanical properties. The morphological changes were studied by FE-SEM and EDS. The test results indicated that the $Al_2O_3$ with nano-sized SiC ceramics sintered at $1800^{\circ}C$ were showed highest density. Sintering temperature at $1800^{\circ}C$, the bending strength of heat treatment in air atmosphere specimens showed about 42 % increment in comparison to the un-heat treated specimens. The cracked specimens can be healed by heat treatment in vacuum atmosphere but the crack healing effect of $Al_2O_3$ ceramics, which is heat treated in air atmosphere was higher than that of heat treated in vacuum atmosphere. $Al_2O_3$ with 30 wt% of SiC ceramics indicated higher crack healing ability than that with 15 wt% of SiC ceramics. The FE-SEM images showed that the median cracks and pores were disappeared after heat treatment in air.

• Applied Chemistry for Engineering
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• v.1 no.2
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• pp.232-239
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• 1990

${\gamma}$-Glycidoxy propyl trimethoxy slilane, CTBN rubber(carboxyl terminated butadiene acrylonitrile rubber) and GMA(glycidyl methacrylate) were reacted with the surface of silica one by one in existence of TEA(triethylamine) or BPO(benzoyl peroxide). The amount of reactant was 2.5~5.8% of treated silica weight. The treated silica was mixed with epoxy resin and MTHPA(methyltetrahydrophthalic anhydride) in the range of 0~60% (wt. %) of total component. The flexural and thermal properties were tested for cured products. In filler content 35~55%, the using of silica treated with silane/rubber or silane/rubber/vinyl represented 25% higher flexural strength, 5% lower flexural modulus and 13% higher than mixing liquid rubber 3% with epoxy resin containing untreated silica.

• International Journal of Highway Engineering
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• v.19 no.2
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• pp.67-74
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• 2017

PURPOSES : The objective of this study is to ascertain the curing period of cementless cold central plant recycled asphalt base-layer, using mechanical analyses and specimen quality tests on the field. METHODS : Cold central plant recycled asphalt base-layer mixture was produced in the plant from reclaimed asphalt, natural aggregate, filler for the cold mix, and the modified emulsion AP using asphalt mix design and plant mix design. In order to examine the applicability of the curing period during the field test, the international standards for the possibility of core extraction and the degree of compaction and LFWD deflection were analyzed. Moreover, Marshall stability test, porosity test, and indirect tensile strength test were performed on the specimens of asphalt mix and plant mix design. RESULTS : The plant production process and compaction method of cementless cold central plant recycled asphalt base-layer were established, and the applicability of the optical moisture content for producing the mixture was verified through the field test. In addition, it was determined that the core extraction method of the conventional international curing standard was insufficient to ensure performance, and the LFWD test demonstrated that the deflection converges after a two-day curing. However, the back-calculation analysis reveals that a three-day curing is satisfactory, resulting in a general level of performance of dense asphalt base-layer. Moreover, from the result of the specimen quality test of the asphalt mix design and plant mix design according to the curing period, it was determined that the qualities satisfied both domestic and international standards, after a two-day curing. However, it was determined that the strength and stiffness after three-day curing are higher than those after a two-day curing by approximately 3.5 % and 20 %, respectively. CONCLUSIONS:A three-day curing period is proposed for the cementless cold central plant recycled asphalt base-layer; this curing period can be demonstrated to retain the modulus of asphalt-base layer in the field and ensure stable quality characteristics.

• Journal of the Korea institute for structural maintenance and inspection
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• v.16 no.5
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• pp.59-67
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• 2012

During the manufacturing of Portland cement, CO2 gas is also necessarily produced through both decarbonation of calcium carbonate and kiln burning. By partially replacing the Portland cement with limestone powder, which is an inert filler in a concrete mixture, CO2 consumption can be reduced in a construction field. This study is to investigate the fundamental durability characteristics of limestone powder added concrete. Experimental variable was the replacement ratio of limestone powder from 0% to 25% with 5% increment. Durability characteristics were investigated by resistance to freeze-thaw, alkali-silica reaction and de-icing chemical in addition to the properties of fresh concrete. From test results, it was observed that the addition of limestone powder did not significantly affect the resistance to freeze-thaw reaction and de-icing chemical. The addition of limestone powder reduced the occurrence potential of alkali-silica reaction by reducing an alkali content in Portland cement.

• Korean Chemical Engineering Research
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• v.50 no.1
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• pp.167-172
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• 2012

A new type of thermoplastic elastomer (TPE) based on EPDM ionomer as an elastomer and polyamide-6 as a reinforcing crystalline polymer was prepared and the thermal properties of TPEs were investigated. Especially effects of neutralization of maleated EPDM (MA-EPDM) to prepare EPDM ionomer with zinc oxide and the content of polyamide-6 on the thermal properties of the blends were investigated. Both the neutralization and blending were carried out employing a twin screw extruder. It was found that the neutralization of MA-EPDM results in the increase of cooling crystallization temperatures. Polyamide-6 plays the role of reinforcing filler in the blends due to the high crystallinity. Fine dispesion of polyamide-6 in the blends was confirmed and attributed to the imide formation between the maleic anhydride of MA-EPDM and amine group of polyamide-6. TPEs based on EPDM ionomer/Polyamide-6 blends showed balanced mechanical properties with improvement in heat resistance.

• Journal of the Microelectronics and Packaging Society
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• v.7 no.3
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• pp.37-44
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• 2000

The corrosion behavior of aluminum pad coated with epoxy molding compound (EMC) was investigated using electrochemical impedance spectroscopy (EIS). The impedance change was evaluated by the absorption of deionized water (DI water) to EMC coating and the interface between EMC and aluminum. During the absorption a decrease in resistance and thus an increase in capacitance of EMC as well as the interface of EMC/Al could be observed. Up to about 170 hours of absorption the EMC was saturated with the water molecules and ions generated from EMC. Subsequently the ionic water was penetrated to the interface and finally the corrosion of aluminum was occurred by the Dl water and ions. From measuring the adhesion strength with the Dl water absorption it was expected that the saturation of water and ions in the interface decreased the adhesion strength. The higher filler content of EMC should be necessary to inhibit the corrosion of aluminum electrode in microelectronic packages.

• Polymer(Korea)
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• v.35 no.5
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• pp.488-492
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• 2011

Three isocyanatopropyldimethoxysilylpolydimethylsiloxanes(IDMSi-PDMS) were synthesised from the reaction of isocyanatopropyltrimethoxysilane with monohydroxyl group termainated PDMS having different molecular weight($M_n$=5000, 10000, and 20000). Then PDMS modified polyurethane hybrid elastomer(PSMPH) were prepared from the reaction of IDMSi-PDMS with ${\alpha}$, ${\omega}$-hydroxyl group terminated polyurethane. PSMPH sealant was prepared by compounding PSMPH elastomer with additives such as plasticizer, adhesion promoter, crosslinking agent, vicosity increasing agent, inorganic filler, and catalyst at room temperature under nitrogen atmosphere. The methoxy group in the PSMPH sealant should be crosslinked with the hydroxyl group in the building stone or moisture by typical sol-gel reaction. The adhesive strength of the sealant having PDMS of $M_n$=5000 showed 40.28 kg of maxium load and 20.14 kg of break load. The shrinkage rate of the sealant having PDMS of $M_n$=20000 was 5.7% as the best result. Also, their skin over time, slump, oil content after 8 days under oil soaked paper and alkaline resistance characteristics show good results.