• 한국산업융합학회 논문집
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• 제2권1호
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• pp.69-75
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• 1999

Intending to develop a new rubber curing process using only microwave, the both the characteristics of cure and the mechanical properties of rubbers for the tire tread, for which a green styrene-butadiene compounds had been cured with 2.45 GHz microwave, have been compared with those of the custom thermal cured rubber. The unintentional hot spot formation in the compound during the microwave curing has not found where the compound has a microwave absorbing ceramic powders in 4.18 weight percents and the supplying voltage has been adjusted to 90 volts. The new microwave process accomplished preheating to 418K in a quarter of the thermal cure time. The average tensile strength of the microwave-cured rubber indicating $190kg/cm^3$ was compatible to that of the thermal cure. In conclusion, the new microwave cure had approved to be applicable in a commercial plant.

• Korean Chemical Engineering Research
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• 제58권1호
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• pp.44-51
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• 2020

n-Methylimidazole, acetonitrile, benzylbromide 및 sodiumhexafluoroantimonate를 이용하여 염기성 촉매 1-benzyle-3-mehyl-imidazolium hexafluoroantimonate (BMH)를 합성하고, tetramethyl biphenol (TMBP)과 epichlorohydrine을 이용하여 결정성 바이페닐 에폭시를 합성하여 FT-IR과 ¹H-NMR으로 구조를 분석하였다. 합성한 촉매 BMH의 경화 거동을 고찰하기 위하여 0 ℃에서 250 ℃까지 5 ℃/min의 속도로 승온시키면서 에폭시 수지에 대하여 BMH의 질량비를 0.5, 1.0, 2.0 wt.%로 변화시켜 시차주사 열량계(differential scanning calorimeter, DSC)로 분석하였다. 그 결과, BMH 촉매는 비스페놀 A형 에폭시와 양이온 중합체의 단계적 가열과정에서 빠른 경화 특성을 보였다. 또한 합성한 바이페닐 에폭시는 일정한 온도에서 급격히 점도가 낮아지는 특성과 바이페놀의 강직한 골격구조를 가지는 특성을 가지고 있기 때문에 결정성 구조 및 고내열성을 요구하는 반도체용 봉지재료의 대표격인 epoxy molding compound (EMC)의 원료로서의 적용 가능성을 고찰하였다. 그 결과, 본 연구에서 개발한 바이페닐 에폭시는 결정성 구조로 이루어진 것을 확인하였으며, 경화제로 페놀 노볼락수지와 고온에서의 경화반응 시, BMH 촉매 존재 시에는 150 ℃ 근처에서 경화반응이 관찰되어 EMC의 원료로 사용될 수 있음을 확인하였다.

• 반도체디스플레이기술학회지
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• 제21권2호
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• pp.57-67
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• 2022

The curing characteristics of naphthalene type epoxy resin systems according to the change of curing agent were investigated to develop a new next-generation EMC(Epoxy Molding Compound) with excellent warpage characteristics, low thermal expansion, and excellent fluidity for WLP(Wafer Level Package). As epoxy resins, DGEBA, which are representative bisphenol type epoxy resins, NE-16, which are the base resins of naphthalene type epoxy resins, and NET-OH, NET-MA, and NET-Epoxy resins newly synthesized based on NE-16 were used. As a curing agent, DDM (Diamino Diphenyl Methane) and CBN resin with naphthalene moiety were used. The curing reaction characteristics of these epoxy resin systems with curing agents were analyzed through thermal analysis experiments. In terms of curing reaction mechanism, DGEBA and NET-OH resin systems follow the nth curing reaction mechanism, and NE-16, NET-MA and NET-Epoxy resin systems follow the autocatalytic curing reaction mechanism in the case of epoxy resin systems using DDM as curing agent. On the other hand, it was found that all of them showed the nth curing reaction mechanism in the case of epoxy resin systems using CBN as the curing agent. Comparing the curing reaction rate, the epoxy resin systems using CBN as the curing agent showed a faster curing reaction rate than them with DDM as a hardener in the case of DGEBA and NET-OH epoxy resin systems following the same nth curing reaction mechanism, and the epoxy resin systems with a different curing mechanism using CBN as a curing agent showed a faster curing reaction rate than DDM hardener systems except for the NE-16 epoxy resin system. These reasons were comparatively explained using the reaction rate parameters obtained through thermal analysis experiments. Based on these results, low thermal expansion, warpage reduction, and curing reaction rate in the epoxy resin systems can be improved by using CBN curing agent with a naphthalene moiety.

• Elastomers and Composites
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• 제55권1호
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• pp.6-12
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• 2020

Poly(ethylene-co-vinyl acetate) compounds and vulcanizates containing dicumyl peroxide (DCP) (HD) were prepared, and the curing agent and reaction products were analyzed using gas chromatography/mass spectrometry (GC/MS). Samples containing trially cyanurate (TAC) and DCP (HDT) were also prepared and analyzed. Some raw DCP were decomposed in the injector region of GC to produce acetophenone. DCP was detected in the HD compound but was not observed in the HD vulcanizate, and instead acetophenone and 2-phenyl-2-propanol were detected. Both DCP and TAC were observed in the HDT compound but not in the HDT vulcanizate, where acetophenone and 2-phenyl-2-propanol were detected. Thus, some of the DCP decomposed during the compounding process. The formation mechanism for acetophenone and 2-phenyl-2-propanol during the crosslinking reaction was identified, and differences in the crosslinking reactions of HD and HDT compounds were discussed.

• Bulletin of the Korean Chemical Society
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• 제33권2호
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• pp.473-482
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• 2012

A novel malemide epoxy containing Co(II), Ni(II) and Cu(II) ions have been synthesized by curing malemide epoxy resin (MIEB-13) and Co(II), Ni(II) and Cu(II) complexes of macrocyclic bis-hydrazone Schiff base. The Schiff base was synthesized by reacting 1,4-dicarbnyl phenyl dihydrazide with 2,6-diformyl-4-methyl phenol. The Schiff base and its Co(II), Ni(II) and Cu(II) complexes have been characterized by elemental analyses, spectral (IR, $^1H$ NMR, UV-vis., FAB mass, ESR), thermal and magnetic data. The curing reaction of maleimide epoxy compound with metal complexes was studied as curing agents. The stability of cured samples was studied by thermo-gravimetric analyses and which have excellent chemical (acid/alkali/solvent) and water absorption resistance. Further, the scanning electron microscopy (SEM) and definitional scanning colorimetric (DSC) techniques were confirmed the phase homogeneity of the cured systems.

• 한국도로학회논문집
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• 제20권2호
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• pp.27-34
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• 2018

PURPOSES : It is necessary to prevent premature failure of concrete pavements caused by durability problems. The purpose of this study was to find factors affecting the durability of concrete pavements, and suggest improvement methods for existing concrete mix design. METHODS : Factors influencing durability were derived from laboratory test data for common field failure conditions and main properties of concrete cores taken from the field. The improvement of concrete properties was investigated by evaluating the performance of existing and proposed mix proportion designs and curing methods. RESULTS : The compressive strength and the absorbing performance of the low Blaine cement and the high-strength mixture were better than those of the Type I cement. Wet curing showed better compressive strength, elastic modulus, coefficient of thermal expansion, and absorption performance than air curing or compound curing. As a result of comparing concrete cores collected in the field, the sections with good durability showed good performance in terms of resistance to chloride ion penetration, absorption, and initial absorption rate. CONCLUSIONS : The absorption performance was considered as a possible foactor affecting durability of cement concrete pavements as a result of field core tests. In order to improve the durability of the pavement concrete, it is necessary to improve the existing mixtures and curing methods.

• 자연과학논문집
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• 제8권2호
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• pp.21-26
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• 1996

시중에서 판매하는 중국산 옻칠을 그대로 혹은 유기용매에 녹는 부분과 녹지 않는 부분으로 분리하고 각각의 경화현상을 연구하였다. 그대로 사용하는 경우에는 상온에서 수분이 포화된 상태에서 경화를 관찰하였으며 유기용매로 분리한 부분의 경화는 섭씨 $100^{\circ}C$와 $150^{\circ}C$에서 경화를 관찰하였다. 서로 다른 방법으로 얻어낸 도막의 성질을 서로 비교하였으며 옻 중 유기용매에 녹는 부분과 1,6-diisocyanohexane, toluendiisocyanate(TDI)를 공중합하였을 때 얻어지는 도막과 다른 도막과의 성질로 비교하였다. 가열하여 형성된 도막은 매우 깨어지는 성질(취성)이 매우 높았으며 자연상태로 경화된 도막에 비하여 친수성이 낮았다. Diisocyanate를 사용하지 않은 경우에는 경화에 산소가 필수적이어서 오랜 시간이 지나도 내부는 경화가 되지 않았다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 C
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• pp.1697-1699
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• 1996

EPDM compound can be cured with either the sulfur and peroxide based systems. In this study, heat resistance and weatherability of EPDM compounds depending on curing systems were investigated. The test results showed that the peroxide-cured EPDM was more resistant to heat ageing and UV photo-degradation than the sulfur-cured EPDM and it is due to C-C bond is more stable than C-S, S-S bond.

• 폴리머
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• 제27권2호
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• pp.142-151
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• 2003

PMMA 판재를 생산하기 위한 두 가지 형태의 방법이 있는 데 셀 주형 방법과 벨트 주형 방법이다. 그러나 이 방법들은 생산성이나 생산 단가 면에서 각각의 단점을 갖고 있다. 그러므로 고분자 가공연구자들은 플라스틱 필름을 주형으로 이용하여 PMMA 판재를 생산하는 새로운 가공 방법기 개발에 많은 관심을 갖게 되었는데 그 이유는 이러한 새로운 가공 방법이 벨트 주형 방법의 생산 단가를 낮출 수 있을 뿐만 아니라 셀 주형 방법의 생산성을 향상시킬 수 있기 때문이다. 그러한 새로운 주형 방법의 개발에 대한 하나의 해결책을 주기 위하여 본 연구에서는 MMA 배합물의 조성 및 경화 조건 PMMA 판재의 가공성 및 기계적 강도에 미치는 영향을 조사하였다. 폴리(비닐 아세테이트) 필름이 PMMA 판재의 생산을 위한 플라스틱 필름 주형으로 사용되었다. 우수한 가공성 및 경화 후 우수한 기계적 특성을 나타내는 MMA 배합물을 결정하기 위하여 성분 및 그들의 조성이 단계적으로 최적화 되었다. 결합제 및 개질제로 작용하는 아크릴산이 PMMA 판재의 기계적 특성의 향상에 중요한 역할을 하는 것으로 나타났다.

• 한국재료학회:학술대회논문집
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• 한국재료학회 1994년도 추계 학술발표 강연 및 논문 개요집
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• pp.125-126
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• 1994

The chemorheological changes and kinetics during curing reaction of an silica filled epoxy system (DGEBA with curing agent Polyxoypropylenediamine) were investigated. This study concentrates on the influence of silica on the reaction kinetics and rheological behavior of the eopxy system. The concentration of the filler was varied 0~200phr. Curing behavior of the silica filled epoxy system was measured at various heating rates with DSC. Conversion was also measured by integrating the obtained DSC curve and Kinetic parameters measured by using the nonlinear regression method. DSC experiments showed that the presence of silica was found to accelerate the progress of the curing reaction and of reduce the heat of reaction compared with that of unfilled epoxy systems . Rheological experiments were conducted on a Physica by using a disposable parallel plate fixture. Material properites were measured such as the elastic modulus(G′), the loss modulus(G"), the loss tangent(tan $\delta$), and the viscosity was at the initial stahe, and the more the silica filler was added, and the lower the gel temperature was in the epoxy system. In this study it is concluded that the curing of the silica filled epoxy system was found to be accelerated, as silica was added to the epoxy compound.