• Polymer(Korea)
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• v.33 no.6
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• pp.615-619
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• 2009

Pd-POSS nanoparticles were produced from the reaction of palladium (II) acetate and octa(3-aminopropyl)octasilsesquioxane octahydrochloride (POSS-${NH_3}^+$) in methanol at room temperature. Pd-POSS nanoparticles with a mean diameter of 60-80 nm were the highly ordered spherical aggregates. In contrast, Pd nanoparticles with a size of 4.0 nm were obtained when POSS-${NH_3}^+$ was not introduced. Pd-POSS/PAA nanocomposites of Pd-POSS nanoparticles and poly(acrylic acid) (PAA) were fabricated by utilizing ionic interactions between positively charged Pd-POSS nanoparticles and negatively charged carboxylate groups of PAA. PAA was used as a cross-linker for the preparation of hybrid nanocomposites with the controlled organized structures of Pd-POSS nanoparticles. That is, the self-organization of Pd-POSS nanoparticles was formed into the shape of continuous lines by using PAA as a cross-linker. The composition, structure, surface morphology, and thermal stability of the Pd-POSS/PAA nanocomposites were studied by FE-SEM, AFM, TEM, FT-IR, and TGA.

• Macromolecular Research
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• v.17 no.8
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• pp.626-629
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• 2009

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.4A
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• pp.761-766
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• 2006

Polymer composite are increasingly considered as structural components for use in civil engineering, on account of their enhanced strength-to-weight ratios. Unsaturated polyester (UP) resin have been widely used for the matrix of composites such as FRP and polymer composite, due to its excellent adhesive. Polymer nanocomposites are new class of composites derived from the nano scale inorganic particles with dimensions typically in the range of 1 to 1000 nm that are dispersed in the polymer matrix homogeneously. Owing to the high aspect ratio of the fillers, mechanical, thermal, flame, retardant and barrier properties are enhanced without significant loss of clarity, toughness or impact strength. To prepare the MMT (Montmorillonite)-UP exfoliated nanocomposites, UP was mixed with MMT at $60^{\circ}C$ for 3 hours by using pan mixer. XRD (X-ray diffraction) pattern of the composites and TEM (Transmission Electron Micrographs) showed that the interlayer spacing of the modified MMT were exfoliated in polymer matrix. The mechanical properties also supported these findings, since in general, tensile strength, modulus with modified MMT were higher than those of the composites with unmodified MMT. The thermal stability of MMT-UP nanocomposite is better than that of pure UP, and its glass transition temperature is higher than that of pure UP. The polymer concrete made with MMT-UP nanocomposite has better mechanical properties than of pure UP. Therefore, it is suggested that strength and elastic modulus of polymer concrete was found to be positively tensile strength and tensile modulus of the MMT-UP nanocomposites.

• Polymer(Korea)
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• v.30 no.4
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• pp.311-317
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• 2006

Poly-DCPD and poly-DCPD/silicates hybrids were prepared by in-situ ROMP poly-merization using $WCl_6$ catalyst. Good dispersion of silicates in DCPD medium can be accomplished by sonication method. Compared with nanocomposites prepared using $Na^+MMT$, the nanocomposites with CL 15A showed well dispersed silicate's morphology. superior thermal and mechanical properties. Additionally, well dispersed silicates in DCPD matrix enhanced the gas barrier property of the nanocomposites.

• Advances in nano research
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• v.2 no.2
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• pp.111-119
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• 2014

The chemical synthesis of anisotropic defective polyaniline/Ag composite (PANI/Ag) is explored using silver nitrate ($AgNO_3$) as the precursor material. This study provides a simple method for the formation of PANI/Ag nanocomposites at two different aniline concentrations $5{\mu}l$ (PANC5) and $10{\mu}l$ (PANC10). The composite PANC5 exhibits UV-Visible absorption peaks at 436 nm and 670 nm whereas, PANC10 exhibits absorption peaks at 446 nm and 697 nm. This shift is caused by the strong interaction between polyaniline and silver. The characterized FTIR peaks observed at around $3410cm^{-1}$ (PANC5) and $3420cm^{-1}$ (PANC10) was due to the N-H stretching vibrations. The appearance of a broad band instead of a sharp peak can be attributed due to the presence of a high concentration of N-H groups in the nanocomposite. The TEM images show that the sample contains defective spherical, truncated triangular and rod shaped particles. The results showed that the PANI/Ag nanocomposites are composed of nano-sized particles of 43-53 nm that contain Ag domains of 33-37 nm with polymer thickness 5.7-11.2 nm at two different aniline concentrations.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.260-260
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• 2010

In recent years, polymer/clay nanocomposites have generated a great interest, both in industry and in academia, because they often exhibit remarkable improvement in material properties when compared with the virgin polymer or conventional micro and macro-composites. Among these properties are stiffness, strength, dimensional stability and permeability. [1-3] The dispersion of hydrophilic silicates in a hydrophobic matrix like Polyethylene (PE) is difficult because of the difference in character between PE and Montmorillonite (MMT). Therefore, it is necessary to modify PE with polar groups, which can increase the hydrophilicity of PE. In this study, High density polyethylene (HDPE)/$Mg(OH)_2$/Montmorillonite (MMT) nanocomposites having a various compositions were prepared by a melt blending technique with an internal mixer and properties namely mechanical, morpology, rheological and thermal properties were investigated

• Composites Research
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• v.33 no.6
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• pp.321-328
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• 2020

Recently, development of nanocomposite materials for applying in various fields has been actively underway. Of the two-dimensional nanomaterials, graphene nanoplatelets (GnPs) are highly utilized because of their excellent properties, but a problem of strong aggregations is occurred when GnPs are fabricated with polymer nanocomposites, so there is a growing demand for research on the methods of dispersion. In this review paper, the research on GnP nanocomposites with improved properties through various dispersion methods of GnPs. The welldispersed GnP nanocomposites will be applied in more diverse fields in the future.

• Journal of Adhesion and Interface
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• v.16 no.3
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• pp.108-115
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• 2015

In the present work, we investigated poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV)/graphene nanocomposites. The electrical, hydrophobic properties and thermal properties of the nanocomposite films having different graphene contents were investigated. The scanning electron microscopy (SEM) morphology showed good dispersion of graphene layers in the PHBV matrix. Based on the X-ray diffraction and differential scanning calorimetry, the addition of graphene increased the crystallinity of PHBV. Thermal stability, hydrophobicity, and electrical conductivity of the nanocomposites were increased with increasing the graphene contents.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.6
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• pp.73-80
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• 2007

Nanocomposites are used as a new class of polymer system and many researchers have been interested in the clay nanocomposite because of its good mechanical properties, heat resistance, flame retardancy, and barrier property. Modified layered silicates as fillers are dispersed at a nanometer-level within a polymer matrix and then new extraordinary properties are observed. In this study, polypropylene/clay nanocomposites were prepared in a twin screw extruder by the melt compounding method. In order to increase the compatibility of PP with the clay, the MAPP was used as a compatibilizer. And organic modified clays were used as a nanometric filler during the melt extrusion. Through the analysis of SAXS, WAXS, the dispersion of clay was investigated. These nanocomposites compared with a neat polypropylene/talc composite have high modulus, low toughness, and reduced shrinkage at the stable dispersion.

• Polymer(Korea)
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• v.26 no.3
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• pp.381-388
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• 2002

The properties of polyurethane (PU) nanocomposites with organoclay have been compared in terms of their thermo-mechanical properties, morphology, and gas permeability. Hexadecylamine-montmorillonite ($C_{16}$-MMT) was used as an organoclay to make PU hybrid films. The properties were investigated as a function of organoclay content (1-4 wt%) in the PU matrix. Transmission electron microscopy (TEM) photographs showed that most clay layers were dispersed homogeneously into the matrix polymer in nano-scale, although some particles of clay were agglomerated. We also found that the addition of only a small amount of organoclay was enough to improve the thermal stabilities and mechanical properties of PU hybrid films while gas permeability was reduced. Even at low organoclay content (<5 wt%), the PU nanocomposite showed much better thermo-mechanical properties, and lower gas permeability than pure PU.