• 폴리머
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• 제28권5호
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• pp.391-396
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• 2004

기존의 에폭시/실리카 나노복합재료의 제조 방법에서 나타나는 문제점인 경화 반응 중의 휘발성 부산물 생성에 의한 미세기공 형성 및 치수 불안전성 등을 극복하고자 Si-N 전구체를 사용한 새로운 방법을 제안하고자 한다. 실리카 전구체로 부산물이 형성되지 않는 메틸트리페닐실란 (MTPS)을 합성하고 이를 이용하여 솔-젤 반응과 에폭시 경화 반응이 병행되는 동시 복합화 반응을 통하여 무기상의 고른 분산상태를 지닌 에폭시/실리카 나노복합재료를 제조하였으며, 이로부터 뛰어난 투명성뿐 아니라 기계적 물성과 열적특성에서 탁월한 물성의 증가를 얻을 수 있었다.

• 박물관보존과학
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• 제26권
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• pp.1-12
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• 2021

석조 문화재 보존처리 시 사용되고 있는 Bisphenol A계 Epoxy 수지의 Yellowing 현상개선과 재료의 다양성 확보를 위해 hydrogenated Bisphenol A계 주제 기반의 석조 문화재 보존용 Epoxy 수지를 제조하여 물성 비교 실험을 진행하였다. 실험 결과 제조한 Epoxy 수지가 인장강도, 접착 강도, 가공성에서 기존 재료보다 향상된 물성을 확인할 수 있었으며, 황변성은 약 5 ~ 8배 개선되었다. 이러한 결과는 대부분이 야외에 위치한 석조 문화재의 특성상 안정적인 보존 재료로서의 적용이 가능할 것으로 판단된다.

• Bulletin of the Korean Chemical Society
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• 제22권4호
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• pp.424-426
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• 2001

• Bulletin of the Korean Chemical Society
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• 제22권12호
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• pp.1393-1396
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• 2001

• Elastomers and Composites
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• 제57권2호
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• pp.48-54
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• 2022

A polymeric adhesion promoter was synthesized to improve the adhesive strength of the Ni lead frame/epoxy composite. Poly(itaconic acid-co-acrylamide) (IAcAAM) was prepared by copolymerizing itaconic acid and acrylamide. We compared the adhesive strength between the Ni lead frame and epoxy composite according to the molecular weight of IAcAAM. The molecular weight of IAcAAM was controlled using an initiator, which made it possible to use IAcAAM in the epoxy molding compound (EMC) manufacturing process by modulating the melting temperature. The adhesive strength of Ni lead frame/epoxy composite increased with the addition of IAcAAM to the epoxy composite. In addition, as the molecular weight of IAcAAM increased, the adhesive strength of the Ni lead frame/epoxy composite slightly increased. We confirmed that IAcAAM with an appropriate molecular weight can be used in the EMC manufacturing process and increase the adhesive strength of the Ni lead frame/epoxy composite.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2013년도 춘계 학술논문 발표대회
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• pp.305-307
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• 2013

In this paper, we test and evaluate in terms of workability the epoxy resin mortar and the EVA powder resin mortar used on the concrete structures. The initial viscosity of the epoxy resin mortar is lower than the EVA powder mortar, but after 20 minutes work can not be rapidly increased to 40 minutes. In the other hand, the EVA powder resin mortar is able to measure of viscosity for the past 40 minutes. In the flow test for evaluate workability, the flow of the epoxy resin mortar is rapidly decreased from 230 to 100 in the 90 minutes, but the flow of the EVA powder resin mortar is reduced to 198 to 175 that there is no significant change. In the coverage test of the pinhole on the concrete surface, the EVA powder mortar appears coverage in the all pinhole size but the epoxy resin mortar is not concealed from 2mm pinhole size.

• Restorative Dentistry and Endodontics
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• 제42권1호
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• pp.27-33
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• 2017

Objectives: To determine the optimal timing for post space preparation of root canals sealed with epoxy resin-based AH Plus sealer in terms of its polymerization and influence on apical leakage. Materials and Methods: The epoxy polymerization of AH Plus (Dentsply DeTrey) as a function of time after mixing (8, 24, and 72 hours, and 1 week) was evaluated using Fourier transform infrared (FTIR) spectroscopy and microhardness measurements. The change in the glass transition temperature ($T_g$) of the material with time was also investigated using differential scanning calorimetry (DSC). Fifty extracted human single-rooted premolars were filled with gutta-percha and AH Plus, and randomly separated into five groups (n = 10) based on post space preparation timing (immediately after root canal obturation and 8, 24, and 72 hours, and 1 week after root canal obturation). The extent of apical leakage (mm) of the five groups was compared using a dye leakage test. Each dataset was statistically analyzed by one-way analysis of variance and Tukey's post hoc test (${\alpha}=0.05$). Results: Continuous epoxy polymerization of the material with time was observed. Although the $T_g$ values of the material gradually increased with time, the specimens presented no clear $T_g$ value at 1 week after mixing. When the post space was prepared 1 week after root canal obturation, the leakage was significantly higher than in the other groups (p < 0.05), among which there was no significant difference in leakage. Conclusions: Poor apical seal was detected when post space preparation was delayed until 1 week after root canal obturation.

• Bulletin of the Korean Chemical Society
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• 제27권10호
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• pp.1542-1548
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• 2006

Maleimide modified epoxy compounds were prepared by reacting N-(4-hydroxyphenyl) maleimide (HPM) with diglycidylether of bisphenol-A. Triphenylphosphine was used as catalyst and methylethylketone as solvent. The resulting compound possessed both the oxirane ring and maleimide group. The curing reaction of the maleimide epoxy compound with amine curing agents such as 1-(2-aminoethyl) piperazine (AEP) and 5-amino-1,3,3-trimethylcyclohexane methylamine isophorone diamine, IPDA) were studied. Incorporation of maleimide groups in the epoxy resin provides cyclic imide structure and high cross-linking density to the cured resins. The cured samples were found to have good thermal stability, chemical resistance (acid/alkali/solvent) and water absorption resistance.

• 한국표면공학회지
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• 제53권1호
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• pp.29-35
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• 2020

In this study, five different specimen preparation methods were introduced and their advantages and disadvantages were presented. One of them, an epoxy mounting method has advantages of constant exposure area, ease of surface preparation without touching the specimen surface during polishing or cleaning, use of small amount of material and ease of specimen reuse by polishing or etching. However, in order to eliminate unexpected errors resulting from preferable reaction at the specimen/epoxy interface and contact resistance between the specimen and copper conducting line for electrical connection, it is recommended to cover the wall side of the specimen with porous anodic oxide films and to remain the contact resistance lower than 1 ohm. The increased contact resistance between the specimen and Cu conducting line appeared to result in increases of anodizing voltage and solution temperature during anodizing by which thickness and hardness of anodizing film on Al2024 alloy were drastically decreased and color of the films became more brightened.

• 한국염색가공학회지
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• 제24권2호
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• pp.145-151
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• 2012

Polymer alloys of poly(ethylene terephthalate)(PET) and nylon6(PA6) which were not miscible each other by themselves were successfully prepared through melt compounding using a twin-screw extruder by utilizing epoxy as reactive compatibilizer. At the epoxy(DGEBA) amount of 0.5~2wt%, the domain size(average diameter) of the discontinuous phase could be reduced up to 0.2${\mu}m$ from 1-5${\mu}m$ that of the simple blend without epoxy. The reaction was presumed to happen mostly at interphase from the result of maximum increase of melt viscosity at the middle range of PET/PA6 blend ratio. It is expected that alloy fibers of PET/epoxy/PA6 with enough mechanical strength for use can be prepared.