• Applied Chemistry for Engineering
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• v.17 no.4
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• pp.357-360
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• 2006

In this study, we studied the physical properties and application of PF foam as heat insulating materials. In the experimental results, the density of PF foam showed $0.030g/cm^3$ and the thermal conductivity showed $0.026kcal/m.h.^{\circ}C$. Also, thermal resistance of the prepared PF foam was volatilized about 71.7 wt% when the temperature was $500^{\circ}C$ (1 h). And the chemical structure of PF foam have a closed cell type in the important properties as heat insulating materials. Therefore, it was confirmed that the prepared PF foam had excellent performance as heat insulating materials.

• Polymer(Korea)
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• v.26 no.3
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• pp.344-352
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• 2002

In this work, two thermal cationic latent catalysts, i.e., triphenyl benzyl phosphonium hexafluoroantimonate (TBPH) and benzyl 2-methylpyrazinium hexafluoroantimonate (BMPH) were newly synthesized. And the thermal and mechanical properties of difunctional epoxy (diglycidylether of bisphenol h, DGEBA) resins initiated by 1 phr of either TBPH or BMPH catalyst were investigated. As experimental results, the epoxy/TBPH system showed higher curing temperature and critical stress intensity factor ($K_{IC}$) than those of epoxy/BMPH. This could be interpreted in terms of slow thermal diffusion rate and bulk structure of four phenyl groups in TBPH. However, the decomposed activation energy determined from Coats-Redfern method was lower in the case of epoxy/TBPH. This result was probably due to the fact that broken short chain structure was developed by steric hindrance of TBPH.

• Applied Chemistry for Engineering
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• v.10 no.5
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• pp.701-706
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• 1999

The effect of siloxane oligomer content on thermal stability and internal stress of DGEBA epoxy resin was investigated. Siloxane-epoxy polymers having terminal epoxy group were prepared by reaction of siloxane-DDM prepolymer with DGEBA epoxy resin. Thermal stability was studied in terms of the initial decomposition temperature(IDT), temperature of maximum rate of weight loss($T_{max}$), integral procedural decomposition temperature(IPDT), and decomposition activation energy($E_t$) using TGA data. The thermal stability increased with increasing the siloxane oligomer content and showed a maximum value in the case of 5 wt% siloxane oligomer content in the blend system. While, the coefficient of thermal expansion(${\alpha}_r$) and the flexural modulus($E_r$) allowed us to study internal stress of the blend system. As the content of siloxane oligomer increases, the internal stress systematically decreases as decreasing both ${\alpha}_r$ and $E_r$.

• Journal of Energy Engineering
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• v.8 no.1
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• pp.189-201
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• 1999

범용 열가소성 플라스틱(polyethylene(PE), polypropylene(PP), polystyrene(PS), polyethylene-terephthalate(PET), acrylonitrile-butandiene-styrene(ABS))과 폐윤활유의 동시처리 열분해반응 실험을 수행하였다. 반응실험은 40$m\ell$ 용량의 회분식 미분반응기(microreactor)를 이용한 실험과 1리터 용량의 autoclave를 이용한 실험의 두 가지로 구분하여 행하였다. 전자의 경우는 통계적 실험적계획법(statistical experimental design)의 하나인 회전계획실험(rotatable design experiments)으로서 오각형 실험계획(pentagonal experimental design)에 의거한 반응변수 실험을 수행한 후 반응표면(response surface)을 회기분석법에 의하여 분석함으로써 최대의 오일 수율을 얻을 수 있는 최적 반응조건을 추적, 결정하였다. Autoclave 반응실험의 기본적인 목적은 실제 연속공정에 있어서 열분해 반응기 거동을 모사하기 위한 전초단계로서 충분한 시료의 확보를 통하여 이 때 생성된 연로유의 체계적인 분석(비등점분포특성, 진공증류, 기체분석, 원소분석, 발열량, 비중 등)을 행함으로써 연료유 수율 및 품질을 모사하고자 하였다. 미분반응기 실험에 있어서 주 범용열가소성수지인 PE, PP 그리고 PS는 각각의 최적반응조건하에서 거의 100%에 가깝게 오일로 전환되었지만 응축수지인 PET와 그래프트공중합수지인 ABS의 오일수율은 각기 78% 및 90%로서 상대적으로 낮게 나타났다. Autoclave를 이용한 실험의 경우 혼합플라스틱을 폐유에 대하여 40wt% 혼합하여 열분해하였을 때, 80wt% 오일, 15wt% 코우크, 그리고 나머지 5wt%는 탄화수소기체(C1-C6)로 전환되었다. 진공증류(252$^{\circ}C$,2 torr) 결과, 기/액-분리도는 3으로서 이는 생성오일의 75wt%가 경질연료유(가솔린, 등유, 경유)로 회수 가능하였다.

• Journal of environmental and Sanitary engineering
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• v.14 no.1
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• pp.31-41
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• 1999

Several new ion exchange resins have been synthesized from chloromethyl styrene-1, 4-di-vinylbenzene with 1%, 2%, 5% and 10%-crosslinking and macrocyclic ligands of cryptand type by interpolymerization method. The adsorption characteristics and the pH, time, solvents and concentration dependence of the adsorption of metal ions by this resin were studied. The correlation between the separation characteristics of uranium and transition metal on the resins and the stability constants of complexes with macrocyclic ligands have been examined. The resins were very stable in both acidic and basic media and had good resistance to heat at $280^{\circ}C$. The $UO_2^{2+}$ aqueous solution was not adsorbed on the resins below pH 3.0, but the power of adsorption of $UO_2^{2+}$ increased rapidly above pH 4.0. The optimum equilibrium time for adsorption of metallic ions was twenty minutes and adsorptive power decreased in proportion to crosslinking size of the resins and order of dielectric constants of solvents used and the selective sequence for metal cations is in the order of $UO_2^{2+}$, $Cu^{2+}$ and $Ce^{3+}$ .

• Journal of Conservation Science
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• v.28 no.2
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• pp.131-139
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• 2012

The exothermic cure kinetics of epoxy resin was controlled by hardener containing fast and slow curing agents. The epoxy risen comprises hydrogenated bisphenol A-based epoxide (HBA), fast curing agent (FH) and slow curing agent poly(propyleneglycol)bis(2-aminopropylether) (SH). Talc was used as an inorganic additive. In the process of curing, cure kinetics along with temperature was monitored by differential scanning calorimeter (DSC) and thermocouple to show that the temperature increase was well controlled by adjusting the hardener mixture. Additionally, bending and tensile strengths of the epoxy/talc composites were also measured to be lower and higher with the amount of the talc inorganic additive, respectively. It is thus concluded that the increase in the temperature during exothermic curing reaction and mechanical properties of epoxy resins are tuned by optimizing hardener mixture for successful stone conservation.

• Elastomers and Composites
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• v.45 no.1
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• pp.12-16
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• 2010

In this work, the effect of hydrophobic treated silica on the water absorption, thermal stabilities, and mechanical properties of the epoxy nanocomposites were investigated as a function of the silica content. As filler, fumed silica treated by dimethyldichlorosilane was used. It was found that the silica was well dispersed in the epoxy resins by the melt-mixing method with the addition of a silane coupling agent. The water absorption of the nanocomposites decreased with an increase of the silica content due to the effect of hydrophobic treated silica. The thermal properties, such as thermal degradation temperature, glass transition temperature ($T_g$), and coefficient of thermal expansion (CTE), of the nanocomposites were improved by the addition of silica. Furthermore, the mechanical properties of the nanocomposites, that is, the tensile strength and modulus, were enhanced with increasing silica content. This was attributed to the physically strong interaction between silica and epoxy resins.

• Journal of the Korean Chemical Society
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• v.40 no.1
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• pp.81-86
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• 1996

The physical properties of epoxy molding compound (EMC) according to the change of softening point of epoxy resin have been investigated in order to study the relationship between the properties of o-cresol novolac epoxy resin, which is main component of EMC for semiconductor encapsulation, and EMC. The softening points of used epoxy resin are 65.1 $^{\circ}C$, 72.2 $^{\circ}C$, and 83.0 $^{\circ}C$, respectively. The flexural strength and flexural modulus as mechanical properties were measured, and thermal expansion coefficient, thermal conductivity and glass transition temperature (Tg) as thermal properties, and spiral flow as moldability have been investigated to see the change of physical properties of EMC. The flexural modulus, thermal expansion coefficients in the glass state (${\alpha}_1$), and thermal conductivity of EMC were found to be keep constant value irrespective of the change of softening point, but Tg increased with softening point of epoxy resin, and the spiral flow decreased with that. It can be considered that these phenomena are due to the increase of crosslinking density of EMC according to the increase of softening point. The transition points were found out in the thermal expansion coefficient data in the rubbery state (${\alpha}_2$) and the flexural strength data. These can show the decrease of filler dispersion according to increase of epoxy resin viscosity.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2011.11a
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• pp.470-473
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• 2011

본 연구에서는 산업현장에서 에폭시 강화촉진제, 도로용 첨가제 등으로 많이 사용되고 있는 경화제(M.E.K)의 혼합비에 따른 자연발화 위험성을 알아보고 산업 현장의 화재 예방을 위한 기초자료로 제공하고자 하였다. M.E.K와 에포비아 수지를 각기 다른 비율로 혼합한 상태에서 시간경과에 따른 시료의 온도변화 와 유증기 발생 및 자연발화 여부를 관찰한 결과 합성수지와 경화제의 혼합시 경화제가 5% 이상으로 혼합될 경우 혼합 수지의 내부온도가 약 $40^{\circ}C$ 이상으로 상승하면서 발포 현상과 함께 다량의 유증기가 발생하였고, 유증기가 발생된 모든 조건에 대하여 자연발화 여부는 확인할 수 없었다.

• Journal of Korea Foresty Energy
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• v.22 no.1
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• pp.24-29
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• 2003

Using woodceramics made from sawdust board of Larix leptolepis thinning logs, change in surface temperature were investigated, by the rate of resin impregnation and burning temperature. As the surface temperature of silicon rubber heater was going up, that of woodceramics also increase rapidly. Woodceramics made from under the condition of the rate of resin impregnation 70-80% and burning temperature 800-$1000^{\circ}C$, were higher than that of surface temperature. Also, it was found that woodceramics maintained heat for a long time because the descending velocity of their surface temperature was lower than that of the heater.