• Bulletin of the Korean Chemical Society
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• v.34 no.1
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• pp.112-116
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• 2013

Surface modification of montmorillonite (MMT) with 3-glycidoxypropyl trimethoxysilane (3GTO) in mild methanol/water mixture has been investigated in detail. The influence of reaction conditions (including silane concentration in feed, reaction time and reaction temperature) on the grafting amount and yield of silane, and further on the grafting pattern of silanes was studied by thermogravimetric analysis, elemental analysis, X-ray diffraction (XRD) and BET. Higher silane concentration, longer reaction time and higher reaction temperature are all benefit to higher grafting amount. When the grafting reaction was performed with 3 mmol/g silane concentration, at $90^{\circ}C$ for 24 h, the grafted amount and yield of silane reached 1.4443 mmol/g and 30%, respectively. Based on the XRD and BET data analysis, a speculation that the grafting pattern of silanes was concentration dependence was proposed.

• Polymer(Korea)
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• v.29 no.4
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• pp.399-402
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• 2005

In this study, ethyl cellulose (EC)/montmorilloniote(MMT) nanocomposite films plasticized with environmental-friendly plasticizer (BET, EBN, ESO) were prepared by melt process using Hakke mixer. The $T_g$ of plasticized EC films decreased from 122 to $71^{circ}C$ with the increase in the BET content up to 30 $wt\%$. The addition of 10 $wt\%$ epoxidized soybean oil (ESO) as the second plasticizer cause the further drop of $T_g$ from 81 to $61^{circ}C$. The plasticizer-effect of BET was better than that of EBN. When the plasticizer was added into the EC films, the mechanical properties of EC films was decreased, however the addition of monotmorillonite (MMT) into the EC films or the ring opening reaction of ESO plasticizer cause enhancement of mechanical properties.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.257-258
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• 2009

Nanocomposites of a epoxy resin are synthesized and evaluated the present study investigated. The effect of nanoclay additives on the properties of diglycidyl ether or bisphenol A(DGEBA) epoxy resin. DGEBA was mixed with 3~7 wt% organically modified layered silicate, Cloisite 30B for three hours. The average grain size of the specimens decreased with adding Cloisite 30B. The dielectric constant showed between 3.2 ~ 3.5 and the dielectric loss showed between 3.2 ~ 5.7 % in all specimens.

• Journal of the Korean Wood Science and Technology
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• v.39 no.5
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• pp.381-389
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• 2011

The effect of organoclays on the mechanical properties of cured phenol formaldehyde resin and oriented strand lumber made from Mountain Pine Beetle killed pine strands was analyzed. Three organoclays were used: a natural montmorillonite, hydrophobic organically modified 10 A, and hydrophilic organically modified 30 B. The oriented strand lumber samples were less creep deformation as well as improved internal bonding strength by adding organoclays in the order of 10 A 2% > MMT 2% > 30 B 2% > control. Furthermore, time-temperature superposition (TTS) analysis was proved to be able to predict the long-term creep behavior of MPB-OSL samples.

• Journal of the Korean Society of Safety
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• v.21 no.1 s.73
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• pp.79-85
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• 2006

Olefinic compatibilized blend(R-PP/R-PE)/layered silicate composites have been prepared by melt intercalation technique directed from $Na^{+}$ montmorillonite(MMT) or organophilic montmorillonites while using magnesium hydroxide as flame retardant. Morphology and flammability properties were characterized by X-ray diffraction(XRD), transmission electron microscopy(TEM), scanning electron microscopy(SEM), thermogravimetry analysis(TGA), limiting oxygen index(LOI), UL94 test. It is found that the compatibilized blend/layered silicate(Cloisite 20A) nanocomposites have a mixed immiscible-intercalated structure and there is better intercalation when a compatibilizer is combined with the polymer and layered silicate to be melt blended. A very large increase in the LOI value was observed with hybrid filler addition and further enhancement in thermal stability and compatibility of blend was obtained for the compatibilized blend containing small amount of layered silicate.

• Corrosion Science and Technology
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• v.9 no.6
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• pp.265-269
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• 2010

This paper describes the exfoliation and surface modification of muscovite mica for UV coating formulation. For the exfoliation of the mica, hydrothermal process was used in the presence of lithium nitrate ($LiNO_3$). After the cation exchange with $Li^+$ ions, the surface of the mica was modified with several amphiphilic substances to increase compatibility and storage stability in UV coating formulation. Such a hydrophobic surface modification affected colloidal stability as well as dispersibility of the exfoliated mica in UV coating solution. Anticorrosive property of mica/UV coated steel plates was tested by salt spray test (SST) and compared with sodium montmorillonite ($Na^+$-MMT)/UV coated steel plates.

• Polymer(Korea)
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• v.37 no.2
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• pp.225-231
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• 2013

Poly(vinyl alcohol) (PVA) hybrid films containing 5 wt% pristine clay mineral were synthesized in the water solution. The various PVA hybrid films were synthesized from structurally different pristine clays: saponite (SPT), montmorillonite (MMT), hectorite (SWN), hydrophilic bentonite (PGV), and mica (Mica). The thermo-optical properties and morphologies of the PVA hybrid films were evaluated with various pristine clays. The nanostructure of the hybrid films was observed using transmission electron microscopy, which showed that the clay layers were well dispersed into the matrix polymer, although some clusters or agglomerated particles were also detected. The addition of pristine clay was more effective with regard to improving the thermal properties and gas barrier characteristics, whereas the optical transparency of the PVA hybrid films deteriorated with pristine clay.

• Polymer(Korea)
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• v.29 no.2
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• pp.190-197
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• 2005

Nanocomposites of three different polyesters with dodecyltriphenylphosphonium-montmorillonite $(C_{12}PPh-MMT)$ as an organoclay are compared with their thermal properties, mechanical properties, and morphologies. Poly (butylene terephthalate) (PBT), poly(ethylene terephthalate) (PET), and poly(trimethylene terephthalate) (PTT) were used as matrix polymers in the fabrication of polyester nanocomposite fibers. The variations of their properties with organoclay content in the polymer matrix and draw ratio (DR) are discussed. Transmission electron microscopy (TEM) micrographs show that some of the clay layers are dispersed homogeneously within the polymer matrix on the nano-scale, although some clay particles are agglomerated. We also found that the addition of only a small amount of organoclay is enough to improve the thermal stabilities and mechanical properties of the polyester nanocomposite fibers. Even polymers with low organoclay contents $(<5\;wt\%)$ were found to exhibit much higher strength and modulus values than pure polyester fibers. In the cases of all polyester hybrid fibers, the values of the tensile mechanical properties were found to decrease linearly with increasing DR. However, the initial tensile modulus of the PTT hybrid fibers were found to be independent of DR.

• Polymer(Korea)
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• v.27 no.2
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• pp.135-141
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• 2003

A series of organophilic montmorillonites (MMTs) modified with various alkyl siloxane amino oligomer groups have been synthesized and their properties were investigated. New organophilic MMTs containing siloxane amino oligomers with alkyl group instead of conventional alkyl amines were synthesized to improve thermal stability as well as gallery spacing. The organophilic MMTs were synthesized from MMT by utilizing the siloxane amino oligomers with various alkyl groups in the water/dioxane solution, which was performed without aq. HCl. Thermal decomposition temperature, gallery spacing, and hydrophobicity of synthesized organophilic MMTs were investigated. X-ray diffraction and TEM experiment results on new organophilic MMTs demonstrated that introduction of siloxane amine oligomers increased d-spacing between silicate layers. The decomposition temperatures of new organophilic MMTs measured by TGA was remarkably improved above 200℃ as compared with those of conventional alkyl substituted organophilic MMTs.

• Korean Chemical Engineering Research
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• v.51 no.3
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• pp.382-387
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• 2013

Biodegradable polyurethane (PU)/clay nanocomposite films were prepared via extrusion compounding process followed by casting film process. Organically modified montmorillonite (denoted as C30B) with a large amount of hydroxyl groups on its surface was used for the formation of strong bonding with PU resin. From both XRD analysis and TEM observations, the intercalated and exfoliated structure, and dispersion state of silicate platelets in the compounded nanocomposite films were confirmed. In addition, the rheological and tensile properties, optical transparency, oxygen permeability of the prepared nanocomposites were investigated as a function of added nanoclay content, and moreover based on these results, the corelation between the morphology and the resulting properties of the nanocomposites could be presented. The inclusion of nanoclays at appropriate content resulted in remarkable improvement in the nanocomposite performance including tensile modulus, elongation, transparency, and oxygen barrier property, however at excess amount of nanoclays, reduction or very slight increase was observed due to poor dispersion. The biodegradability of the prepared nanocomposite film was evaluated by examining the deterioration in the barrier and tensile properties during degradation period under compost.