• Polymer(Korea)
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• v.25 no.3
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• pp.414-420
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• 2001

In this study, the effect of type of intercalant on properties of epoxy nanocomposites was investigated. Cetyltrimethylammoniumbromide (CTMA) as an alkylammonium salt and cetyltributylphosphoniumbromgide (CTBP) as an alkylphosphonium salt were used to modify sodium montmorillonite. In the case of using the CTMA as an intercalant, the long spacing of the silicate layer was about $18.8 {\AA}$. When CTBP was used, the long spacing of the silicate layer ( $23.8{\AA}$) was higher than that of CTMA. From these results, the characteristic length of the modified silicate was found to be significantly affected by the type of intercalant. We also noted that the thermal stability of modified MMT were affected by the type of intercalant, but in the epoxy nanocomposites prepared from the modified MMT, the thermal stability remains almost the same regardless of the type of intercalant. Tensile strength and elongation of epoxy nanocomposites prepared from MMT modified with CTBT were found to be higher than those of the epoxy nanocomposite prepare with WT modified with CTMA.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2001.10a
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• pp.125-128
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• 2001

In this wort, the $Na^+-MMT$ has organically modified with silane intercalant to prepare the polymer/clay nanocomposites. The pH. X-ray diffraction (XRD), and contact angles were used to analyze the surface properties of clay and the exfoliation phenomenon of clay interlayer, The mechanical interfacial properties of epoxy/clay nanocomposites were investigated by three-point bending test. From the experimental results. the surface modification made by silane intercalant on clay surface leads to an increase of distance of silicate layers, surface acid value. and electron acceptor parameter of organoclay. The treatments are also necessary and useful for epoxy to intercalate into the interlayer by interacting of electron donor-accepter between basic epoxy and clay surface. The mechanical interfacial properties of the nanocomposites was improved by the presence of dispersed clay nanolayer containing low content of organoclay in comparison with the conventional, which increase the interfacial adhesion between dispersed clay and epoxy resins.

• Macromolecular Research
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• v.8 no.2
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• pp.95-101
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• 2000

Clay/poly(styrene-co-acrylonitrile) copolymer (SAN) hybrids have been prepared by simple meltmixing of two components, SAN and organophilic clays with a twin screw extruder. Effects of intercalant on the dispersibility of silicate layers in clay-dispersed nanocomposite were studied by using five different organophilic clays modified with the intercalants of different chemical structures and different fractions of intercalant. The dispersibility of 10-$\AA$-thick silicate layers of clay in the hybrid was investigated by using an X-ray diffractometer and a transmission electron microscope. It was found that if the fraction of intercalant in the organophilic clay becomes too high, SAN is difficult to intercalate into the inter-gallery of silicate layers in the hybrid prepared at 180$\^{C}$, and thus the hybrid shows poor dispersibility of silicate layers. The flexural modulus of the hybrid increases as the dispersibility of silicate layers in the hybrid increases.

• Macromolecular Research
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• v.8 no.3
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• pp.120-124
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• 2000

Clay-dispersed nanocomposites have been prepared by simple melt-mixing of two components, styrenic polymers with different content of functional groups and two different organophilic clays (Cloisite(R) 25A and Cloisite(R)30A) with a twin screw extruder. Dispersibility of 10-$\AA$-thick silicate layers of clay in the hybrid was investigated by using an X-ray diffraction method and a transmission electron microscope. It was found that if the interaction force between intercalant and matrix polymer is attractive, the matrix polymer intercalates more rapidly into the gallery of silicate layers. The faster intercalation of matrix polymer leads to the better dispersibility of silicate layers in the matrix polymer.

• Analytical Science and Technology
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• v.10 no.3
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• pp.209-215
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• 1997

Li-AGICs as a anode of secondary battery were synthesized by high-pressure method as a function of the Li-contents. The characteristics of these prepared compounds were determined from the studies with X-ray diffraction method, UV/VIS spectrophotometric and differential scanning calorimeter(DSC) analysis. From the results of X-ray diffraction, it was found that the lower stage intercalation compounds were formed with increase of Li-contents. The mixed stages in these compounds were also observed. In the case of the $Li_{30wt%}$-AGIC, the compounds in the stage 1 structure were formed predominantly, but the structure of only pure stage 1 for structural defect of artificial graphite is not observed. According to UV/VIS spectrophotometric analysis, $Li_{30wt%}$-AGIC shows distinguishable energy state spectrum with the position of $R(%)_{min}$ values, but the characteristic spectra of almost all Li-AGICs are not observed. The enthalpy and entropy changes of the compounds can be obtained from the differential scanning calorimetric analysis results. From the results, it was found that exothermic and endothermic reactions of Li-AGICs are related to thermal stability of lithium between artificial graphite layers.

• Journal of the Korean Ceramic Society
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• v.53 no.4
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• pp.417-428
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• 2016

In this review, an attempt is made to calculate one-dimensional (1-D) electron density profiles from experimentally determined (00l) XRD intensities and possible structural models as well in an effort to understand the collective intracrystalline structures of intercalant molecules of two-dimensional (2-D) nanohybrids with heterostructures. 2-D ceramics, including layered metal oxides and clays, have received much attention due to their potential applicability as catalysts, electrodes, stabilizing agents, and drug delivery systems. 2-D nanohybrids based on such layered ceramics with various heterostructures have been realized through intercalation reactions. In general, the physico-chemical properties of such 2-D nanohybrids are strongly correlated with their heterostructures, but it is not easy to solve the crystal structures due to their low crystallinity and high anisotropic nature. However, the powder X-ray diffraction (XRD) analysis method is thought to be the most powerful means of understanding the interlayer structures of intercalant molecules. If a proper number of well-developed (00l) XRD peaks are available for such 2-D nanohybrids, the 1-D electron density along the crystallographic c-axis can be calculated via a Fourier transform analysis to obtain structural information about the orientations and arrangements of guest species in the interlayer space.

• Applied Chemistry for Engineering
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• v.16 no.2
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• pp.212-216
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• 2005

Benzotriazole which is used as a corrosion inhibitor for the zinc coated steel was intercalated into Na-MMT. X-ray diffraction experiments on intercalant/silicate composite samples demonstrated that the intercalation of intercalant leads to an increase in the spacing between silicate layers. Water soluble poly(ethylene-co-acrylic acid) (PEA) nanocomposites, to use as a coating agent, were prepared with these modified MMT. We found that mono-layered silicates were dispersed in PEA matrix and those resultants were exfoliated nanocomposites. From the result of salt spray test, we found that this coating agent prepared with water soluble poly(ethylene-co-acrylic acid) (PEA) nanocomposite provided good corrosion protection. These results were caused by decreasing the rate of oxygen permeation from silicate layers dispersed homogeneously in PEA matrix and the effect of corrosion inhibitor from benzotriazole.

• Journal of the Korean Society of Industry Convergence
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• v.12 no.1
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• pp.5-10
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• 2009

The Nylon/clay nanocomposite were prepared with Cloisite25A and Cloisite30B. And mechanical properties and thermal properties of Nylon/clay nanocomposites on the amount of MMT have been investigated. From the results of XRD and TEM, we found that mono layered silicates were dispersed in polymer matrix and those resultants were exfoliated nanocomposites. When Cloisite30B was used as an intercalant in the Nylon/Clay nanocomposites, the mechanical and thermal properties of Nylon were higher than those with Cloisite25A.

• Macromolecular Research
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• v.8 no.4
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• pp.186-191
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• 2000

Clay-dispersed nanocomposites have been prepared by simple melt-mixing of three components, i.e. poly (styrene co-acrylonitrile) copolymer (SAN), poly ($\xi$-caprolactone ) (PCL), and an organophilic clay(Cloisite(R) 30A). In the present study, poly($\xi$-caprolactone) was added in the mixtures in order to facilitate the intercalation of SAN into the gallery of silicate layers, and the molecular weight effects of PCL on the dispersion of silicate layers were compared by changing the amount of added PCL. The degree of dispersion of 10-$\AA$-thick silicate layers of clay in the nanocomposites was investigated by using an X-ray diffractometer and a transmission electron microscope. It was found that PCL added in the mixture facilitate the intercalation of SAN copolymers into the galleries of silicate layers modified with an organic intercalant, resulting in the better dispersion of clay. It was, also, observed that the processing temperature influences the degree of clay dispersion.

• Polymer(Korea)
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• v.27 no.1
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• pp.75-83
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• 2003

Dicyanate-clay nanocomposite has been prepared by a melt in-situ polymerization method for different modifiers and cation exchange capacity (CEC) values in order to study dispersion and mechanical property. Various dicyanate nanocomposites were prepared by using different MMT systems containing different intercalants which led to different initial gallery heights and packing density. Depending on compatibility between dicyanate and clays, the degree of dispersion varied. Dispersion of clay plates in dicyanate resin depended mainly on CEC and aliphatic chain length of modifier. The lower CEC and shorter aliphatic chain length of modifier gave the exfoliation structure. It was also found that the reactivity of intercalant with dicyanate resin was one of the key factors facilitating the intercalation/exfoliation process of dicyanate/MMT nanocomposites. Shear modulus of reaction-induced dicyanate nanocomposite was significantly increased.