• 한국광물학회지
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• 제4권2호
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• pp.90-98
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• 1991

This study introduces a new structural model of 1M 2:1 trioctahedral clay minerals or, more generally, 2:1 trioctahedral phyllosilicates. The structural model requires only the chemical formulae of the clay minerals as an input and uses the regression relation (Radoslovich, 1962) to calculate the a- and b-dimensions of the phyllosilicates with the given chemical formulae. The atomic coordinates of the constituent atoms are geometrically calculated for C2/m space group under the assumption that the interatomic distances are constant. To determine the c-dimension, this study calculates the binding energies of 1M 2:1 trioctahedral phyllosilicates as a function of d(001) and find the minimum energy producing d(001). The structural model generates the cell dimensions, interaxial angles, interatomic distances, octahedral, tetrahedral and interlayer thickness, polyhedron deformation angles and atomic coordinates in the unit cell. The simulated structural parameters of phlogopite and annite are very close to the reported data by Hazen and Burnham (1973), suggesting that the structure simulation using only the chemical formule is successful, and thus, that the structural model of this study overcomes the difficulties in the previous models by other investigators.

• Bulletin of the Korean Chemical Society
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• 제10권1호
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• pp.27-30
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• 1989

Lithium has been intercalated into $FeMoO_4Cl$, and deintercalated from $LixFeMoO_4Cl$ both electrochemically and chemically. The inserted $Li^+$ ions are stabilized in the distorted octahedral field in interlayer space of $FeMoO_4Cl$. The crystal symmetry is reduced from tetragonal to monoclinic due to the reduction of ferric to ferrous ions in $LixFeMoO_4Cl$ upon lithium intercalation. From the magnetic and structural data, it has been concluded that the high-spin electronic configuration of $Fe^{2+}(d_{xz}^2{d_{y2}^1}{d_1}{2d_z^12}{\cdot}_y2)$, corresponding to $^5E_g$, group term in $D_{4h}$ symmetry, can be stabilized by the elongation of $FeO_4Cl_{2-}$octahedra in a weak ligand field.

• Bulletin of the Korean Chemical Society
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• 제21권10호
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• pp.1049-1051
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• 2000

A chromia-pillared clay has been prepared by ion exchange type intercalation reaction between the sodium ion in montmorillonite and the trimeric chromium oxyformate (TCF) ion, and by subsequent heat-treatment. The structural and thermal properties have been systematically studied by thermal analysis, powder XRD, IR spec-troscopy, and XAS. The gallery height of~6.8 $\AA$ upon intercalation of the TCF ion suggests that the $Cr_3O$ plane is parallel to the aluminosilicate layers. Even though the basal spacing of TCF intercalated clay decreases slightly upon heating, the layer structure was retained up to $550^{\circ}C$ as confirmed by XRD and TG/DTA. Ac-cording to the EXAFS spectroscopic analysis, it is identified that the (Cr-Cr) distance of 3.28 $\AA$ between vertex-linked CrO6 octahedra in TCF splits into 2.64 $\AA$, 2.98 $\AA$, and 3.77 $\AA$ due to the face-, edge-, and corner-shared CrO6 octahedra after heating at $400^{\circ}C$, implying that a nano-sized chromium oxide phase was stabilized within the interlayer space of clay.

• 한국전기전자재료학회논문지
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• 제21권6호
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• pp.544-551
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• 2008

We have studied the dielectric characteristics of low-k interlayer dielectric materials fabricated by PECVD for various precursor's flow rates. BTMSM precursor was introduced with the flow rates from 42 sccm to 60 sccm by 2 sccm step in the constant flow rate of 60 sccm $O_2$. The absorption intensities of Si-O-$CH_x$ bonding group and Si-$CH_x$ bonding group changed synchronously for the variation of precursor flow rate, but the intensity of Si-O-Si(C) responded asynchronously with the $CH_x$ combined bonds. The heat treatment reduced the FTIR absorption intensity of Si-O-$CH_x$ bonding group and Si-$CH_x$ bonding group but increased the intensity of Si-O-Si(C). The nanopore and free space formed by the increasement of caged link mode and cross link mode of Si-O-Si(C) group implied the origin of low-k SiOCH films.

• 공업화학
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• 제16권4호
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• pp.576-580
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• 2005

Magadiite 주형에 PFO (pyrolized fuel oil)와 Cobalt(II)2-ethylhexanoate 촉매를 함께 층간 삽입, $900{\sim}1100^{\circ}C$에서 3~24 h 동안 열분해하여 층간에 흑연 박막을 형성하고 magadiite 주형을 제거함으로서 다공성 흑연을 합성하였다. 소성시간이 길어질수록, 소성온도가 높을수록 흑연의 결정화도가 향상되었다. 비표면적은 PFO의 혼합비율, 소성시간, 소성온도에 따라 $261{\sim}400m^2/g$의 크게 다른 값을 나타내었다.

• 공업화학
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• 제28권5호
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• pp.495-500
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• 2017

본 연구에서는 마그네슘 이온 및 (3-aminopropyl)triethoxysilane (APTES)으로 표면에 amine group이 부착된 아미노클레이를 합성(AC)함과 동시에 천연 화합물인 프로폴리스 및 황련 추출물을 클레이 시트 사이에 삽입한 클레이를 합성(PIAC, CIAC)하였다. 주사전자현미경, 입도 분석법, FT-IR, TGA 및 XRD를 통해 클레이의 합성 및 천연 화합물의 삽입을 확인하였고, 특히 XRD data에서 천연 화합물의 삽입에 따른 층간거리(d-space)를 분석함으로써 명확하게 그 특성을 결정하였다. 또한 천연 화합물이 삽입된 클레이인 PIAC 및 CIAC의 경우 삽입되지 않은 아미노클레이(AC)에 비해 항균성이 향상된 것을 최소저해농도(MIC) 분석을 통해 확인하였다.

• 한국분말재료학회지
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• 제12권2호
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• pp.122-130
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• 2005

Layered silicate was synthesized at hydrothermal condition from silica adding to various materials. Nano-clay was synthesized by intercaltion of various amine compounds into synthetic layered silicate. The products were analysed by XRD, SEM, and FT-IR in order to examine the condition of synthesis and intercalation. From the results, it was confirmed that kaolinite was synthesized from precipitated silica and gibbsite at $220^{\circ}C$ during 10 days, and hetorite was synthesized from silica sol at $100^{\circ}C$ during 48 h. Na-Magadiite was synthesized from silica gel at $150^{\circ}C$ during 72 h, and Na-kenyaite was synthesized from silica gel at $160^{\circ}C$ during 84 h. Nano-clay was prepared using synthetic layered silicate intercalated with various amine compounds. Kenyaite was easily intercalated by various organic compounds, and has the highest basal-spacing value among other layered silicates. Basal-spacing was changed according to the length of alkyl chain of amine comopounds. Polymer can be easily intercalated by dispersion with large space of interlayer. Finally, epoxy/nano-clay nanocomposite can be easily prepared.

• Bulletin of the Korean Chemical Society
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• 제19권11호
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• pp.1185-1188
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• 1998

Layered nanocomposite, SiO2/TiO2 sol pillared clay, has been prepared by the ion exchange reaction of Na' ion in montmorillonite with positively charged mixed SiO2/TiO2 sol. The nanosized sol particles were synthesized by mixing SiO2 sol solution with TiO2 one, which is obtained by acidic hydrolysis of TEOS and TiCl4, respectively. From powder XRD, the basal spacing (d001) of the sample calcined at 400 ℃ was found to be ca. 60 Å, due to the multistacking of nanosized SiO2 and TiO2 sol particles, which was confirmed by the pore size analysis from 129Xe NMR and micropore analysis calculated from nitrogen adsorption. The BET specific surface area shows the value of 684 m2g-1 (Langmuir 1115 m2g-1), which is the highest among various pillared clays ever reported previously, and the total porosity is found to be 0.51 mlg-1, and the pores are mainly composed of micropore with a size of ca. 11.8 Å. This result agrees with the adsorption capacity obtained from water adsorption. According to diffuse reflectance ultraviolet-visible spectroscopy, it is found that the TiO2 particles stabilized in the interlayer space of montmorillonite are quantum-sized of ca. 20 Å.

• Bulletin of the Korean Chemical Society
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• 제21권3호
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• pp.305-309
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• 2000

The cerium ion intercalated aluminosilicate was prepared by ion exchange reaction between $Na^+$ in montmorillonite and $Ce^{+4}$ in aqueous solution. The X-ray absorption near edge structrure(XANES) analyses indicate that the $Ce^{+4}$ ions are partially reduced to the $Ce^{+3}$ ones during the intercalation into layered aluminosilicate due to a charge transfer between host and intercalant. From the EXAFS analysis, two different (Ce-O) bonding pairs could be characterized with the distances and coordination numbers of 2.31 $({\pm}0.02){\AA}$ ${\times}$ 8.2 $({\pm}1.5)$ and 2.66 $({\pm}0.02){\AA}$ ${\times}$ 2.7 $({\pm}1.0)$, respectively, with the oxygen atoms as the first nearest neighbor, and two (Ce-Ce) pairs at 3.78 ${\AA}$ as the second neighbor. It is therefore concluded that the most probable Ce-species stabilized in the interlayer space of aluminosilicate after the intercalation is the tetrameric Ce-polyoxy/hydorxy cations with the mixed valent state of 0.75 $Ce^{+4}$.0.25 $Ce^{+3}$.

• 폴리머
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• 제24권4호
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• pp.571-577
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• 2000

본 연구에서는 새로운 형태의 에폭시 -광물 라노복합재료를 합성하기 위한 충전재를 층상 화합물인 나트륨-montmorillonite (Na-MMT)와 octadecyltrimethylammonium bromide와의 이온교환 반응으로부터 얻었다. 이렇게 합성된 octadecyltrimethylammonium-MMT에 3-aminopropyl triethoxysilane (APS)를 반응시켜 층상물질의 내부에 aminopropyl기가 삽입된 $C_{18}$ H$_{37}$ N($CH_3$)$_3$-APS-MMT를 합성하였다. 개질된 MMT의 층간저리와 구조를 X-선 회절 (XRD), IR 그리고 고상 $^{29}$ Si CP/MAS NMR을 이용하여 확인하였다. 이어서 $C_{18}$ H$_{37}$ N($CH_3$)$_3$-APS-MMT 존재하에 diglycidyl ether of bisphenol A (DGEBA)를 중합시켜 광물-고분자 나노복합재료를 합성하였다. 그리고 얻어진 나노복합재료의 구조를 XRD, 투과전자현미경 (TEM) 그리고 주사전자현미경 (SEM)으로 확인하였다. 확인 결과 합성된 유기몬모릴로나이트는 에폭시 고분자 내에서 실리케이트 층이 완전히 박리되어 있으며 단일층으로 고분자 매트릭스 내에 잘 분산되어 있음을 알았다.