• 대한화학회지
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• 제25권3호
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• pp.140-144
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• 1981

추진제 성형에 쓰이는 isophorone diisocyanate의 구조와 반응성을 EHT, DNDO/2 및 STO-3G 방법으로 고찰하였다. 반응성은 -NCO기의 탄소원자의 양전하로 결정되며, 이 화합물의 구조는 반응성이 느리고 균일한 matrix 성형이 이루어지도록 되어 있는 것을 알았다.

• 보존과학회지
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• 제28권2호
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• pp.131-139
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• 2012

석조문화재의 보존 복원 과정에 적용되는 에폭시 수지에 경화제의 혼합을 통하여 경화 시 발열 반응을 제어할 수 있는 접착 시스템을 연구하였다. 사용된 에폭시 주제는 hydrogenated bisphenol A (HBA), 경화제로는 속경화형 경화제 FH와 poly(propyleneglycol)bis(2-aminopropylether) (SH)를 사용하였으며, 무기 첨가물은 탈크를 사용하였다. 에폭시 수지와 경화제의 혼합비에 따라 경화 시 온도를 측정하고, differental scanning calorimeter (DSC)를 이용하여 경화동력학을 확인하였으며, 기계적 특성을 파악하기 위해 무기 첨가물의 함량에 따른 인장강도, 전단강도를 측정하였다. 연구 결과, 에폭시 수지의 경화제 혼합을 통하여 경화 시 반응열 상승폭 제어 및 경화 거동 제어의 가능성을 확인하였으며, 무기 첨가물 첨가를 통해 적절한 강도 조절이 가능하여 석조문화재에 적용 가능한 새로운 접착 시스템을 개발하였다.

• Restorative Dentistry and Endodontics
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• 제20권2호
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• pp.487-507
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• 1995

Composite resin repair requires strong bond strength between the new and old materials. The objective of the current study was to identify the optimal treatments for sufficient bond strengths. Bondings between same kinds of materials and cross bondings using chemical curing composites and light curing composites were tested. Surface treatments included the methods of sand-blasting, acid etching and coating of bonding agent. Seven kinds cases of combinations from three kinds of methods were experimented and compared with a control group of which surfaces were highly polished. Measurements of shear bond strength and observations of surface morphologic changes using a scanning electron microscope were done. Following conclusions were drawn : 1. The highest bond strength among composite resins were exhibited by the treatment of the sand-blasting and the coating of bonding agent. 2. Acid etched surfaces showed the lowest bond strength. Bond strengths obtained from experimental groups including acid etching were lower than those obtained from same kinds of experimental groups without acid etching. 3. Simple method of the coating of bonding agent produced the slightly increased bond strength on chemical curing composite and reduced bond strength on light curing composite. 4. Bonding surfaces of chemical curing composite resin showed slightly higher bond strengths than light curing composite resin, however significant differences were not confirmed statistically. 5. More significant irregular surfaces were created by sand-blasting method than acid etching method. 6. A principal component of fillers of both resins was silicon. Acid etching method produced the seperations and degradations of fillers, these were significant on light curing composite resins which containing barium fillers.

• 한국염색가공학회지
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• 제11권6호
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• pp.7-17
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• 1999

Aminophosphazene derivatives were prepared from hexachlorocyclotriphosphazene and used for the curing agents of epoxy resins. The effect of the curing agent on the dynamic viscoelastic properties, flame proofing, and heat resistance of the cured epoxy resins were investigated and compared with those for the epoxy resins cured with aliphatic and aromatic amines. The epoxy resin cured by 1,1-diamino-3,3,5,5-tetrachlorocyclotriphosphazene showed the highest storage modulus and glass transition temperature when cured at 19$0^{\circ}C$ for 6 hours. The epoxy resins cured with phosphazene derivatives showed superior flame proofing to those with aliphatic amine and aromatic amine. Particularly it is an effective curing agent for epoxy resins to enhance the storage modulus, flame proofing and resistance to heat.

• Elastomers and Composites
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• 제22권4호
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• pp.305-313
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• 1987

In this study, as one of the developing ways of the functional elastomer, improvement of the functionality of 1-Chlorobutadiene-Butadiene Copolymer(CB-BR) was attempt through curing reaction by moisture. The curing reaction of CB-BR was determined an use of $\gamma$-Aminopropyltriethoxysilane(APS) and $\gamma$-Aminopropylmethyldiethoxysilane(ADS) as a crosslinking agent with filler at so the uncrosslinked elastomer was exposured in the air and curing reaction by moisture in the air was studied. The results obtained are as follows. 1. APS was more efficient than ADS as a crosslinking agent for CB-BR 2. Optimum amount of APS for moisture cured elastomer was r=1.5(at the ratio of $[APS]/[Cl^*]$) also in case(r=1.5), elastomer formed after soaking $T_{72}$ had similar physical properties with elastomer crosslinked by sulfur and it was very good. 3. Uncrosslinked elastomer(CB-BR+APS+Silica) was easily crosslinked by exposure to the air, and the physical properties was also satisfactory.

• 한국염색가공학회지
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• 제17권6호
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• pp.27-35
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• 2005

Conventional pad- dry-cure(thermo-fixation) process usually produces functional performance on both sides of a fabric. UV curing technique was applied to impart water- and oil-repellent finish effective only on the face of a PET knitted fabric. The preferential one-side coating, by virtue of the limited penetration of UV light, was achieved by W curing after padding of a fluorocarbon agent without special coating or printing equipments. The difference in the functional property of face and back sides was examined by measuring water and oil repellency at each side of the treated fabric. The influence of pre/post-irradiation dose and agent concentration on the performance of the finished fabrics were investigated. While increase in both resin concentration and post-irradiation did not have significant effect on the finish, UV pre-irradiation of PET fabrics caused remarkable influence presumably due to appropriate surface modification of PET fabrics required for facile wetting of the resin. The dimensional stability and color change of the UV cured fabrics measured by FAST and reflectance spectrophotometry showed significantly decreased color difference and increased percent extension compared with the samples pre-irradiated without agent application.

• 한국응용과학기술학회지
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• 제18권1호
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• pp.29-39
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• 2001

An acrylic resin was synthesized with several monomers, styrene(St), 2-hydroxyethyl methacrylate(2-HEMA), n-butyl acrylate, methyl methacrylate, and acetoacetoxyethl methacrylate(AAEM) to prepare a high-solid coatings. Then, a high-solid acryl/melamine coatings was prepared by curing the acrylic resin with a curing agent, hexamethoxymethylmelamine(HMMM). The curing behavior of the acrylic resin with HMMM was investigated by the Ozawa method using DSC. For AAEM/HMMM and 2-HEMA/HMMM curing reactions, activation energies were 33.01 and 27.12 kcal/mol and frequency factors were $9.54{\times}10^{15}}$ and 1.53{\times}10^{13} $min^{-1}$, respectively. From the results, it was found out that 2-HEMA showed higher reactivity with the curing agent than AAEM.

• International Journal of Ocean System Engineering
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• 제3권2호
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• pp.102-110
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• 2013

The purpose of this study was to improve the properties of epoxy resin using titanium oxide nanoparticles. The effects of particle weight fraction, dispersion agent, and curing agents with different molecular weights on the thermal and mechanical properties of titanium-oxide-reinforced epoxy resin were investigated. In addition, the effect of the particle dispersion condition on the mechanical properties of nanocomposites was studied. As a result, it was found that the glass transition temperature of film-shaped nanocomposites decreased with an in-crease in the nanoparticle content. Because nanoparticles interrupted the cross linkage between the epoxy resin and the amine curing agent, the cross-link density of the epoxy became lower and led to a decrease in $T_g$ in the nanocompo-sites. The tensile strength and modulus in film-shaped nanocomposites also increased with the particles content. But in the case of dog-bone-shaped nanocomposites, the values were not similar to the trend for the film-shaped nanocompo-sites. This was probably a result of the different nanoparticles dispersions in the epoxy resins resulting from the respective-thicknesses of the film and dog-bone-shaped samples.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2020년도 가을 학술논문 발표대회
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• pp.10-11
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• 2020

This research is part of the research for unifying the mass concrete and utilizing the rate of super retarding agent. We analyzed the performance of super retarding agent under low temperature conditions. It was found that there was no deterioration in fluidity and air quality due to the change in the super retarding agent mixing rate. It was found that when super retarding agent was mixed up to 0.5 %, it was delayed for 22.3 hours at 20℃, 48.2 hours at 10℃, and 48.5 hours at 5℃. Therefore in order to ensure the performance required at the site, the super retarding agent mixing rate must be determined by fully considering the situation at the site. In addition it will be analyzed that super retarding agent performance analysis at high temperature will be required in subsequent studies.

• 폴리머
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• 제25권4호
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• pp.503-511
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• 2001

기존 실리카 분산제는 주로 Zn, K의 지방산 유도체이며 지방산과 금속비누의 혼합물은 활성을 높이는데 사용되었다. Zn-K 비누 형태의 실리카 분산제는 탄화수소 사슬의 유동성을 증가시켜 실리카가 함유된 고무 배합물의 점도를 낮추어 주며 그 결과 가공성이 향상된다. 실리카 분산제는 가류 특성에 영향을 미쳐서는 안되는데 Zn-K 비누형태의 분산제는 스코치 및 가류시간을 단축시켰다. 그러나 새로이 개발된 분산제의 경우 금속을 함유하지 않은 non-metal 형태이며 분산제가 실리카와 고무간의 interaction을 유도하여 실리카 분산도를 크게 향상시켰으며 이로 인해 경도 및 점도 저하를 유도하였다. 또한 새로운 분산제는 실리카 고무배합물의 가교특성 및 스코치 안정성에 영향을 미치지 않았다.