• Elastomers and Composites
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• 제41권1호
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• pp.27-39
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• 2006

본 연구에서는 컴파운딩법 (compounding method)과 라텍스법 (latex method)을 이용하여 dodecylamine으로 유기화한 MMT(DA-MMT)로 보강된 천연고무-클레이 나노 복합재료를 제조하였다. 또한 Cloisite 15A, carbon black, Na-MMT 충전 배합고무와 라텍스법 (latex method)을 이용한 DA-MMT 충전 배합고무의 가황 특성 및 기계적 물성을 비교하였다. 카본블랙을 제외한 모든 충전제의 함량은 10 phr로 고정하였다. XRD 패턴을 분석한 결과 롤밀 작업 후에 가장 많은 삽입과 박리가 이루어져 NR/DA-MMT 나노 복합재료에서는 DA-MMT의 전체 silicates layer가 $13{\sim}14$층에서 $2{\sim}3$층의 silicates의 형태로 박리된 것을 확인할 수 있었다. 하지만, 가교 과정에서의 높은 열과 압력으로 인해 일부 유기화제가 빠져나감으로써 층간 거리가 감소된 DA-MMT도 존재하였다. 이는 TEM 결과에서도 확인할 수 있었다. 가교도의 경우 NR/Cloisite 15A 컴파운드가 가장 높은 값을 나타내었다. 하지만 가황 특성에서 동일 함량의 충전제가 첨가된 고무의 가황 특성을 비교하면, NR/DA-MMT 컴파운드가 가장 높은 ODR 토크 값을 나타내었고, 또한 가장 높은 인장 강도, 모듈러스 및 인열강도를 나타냄을 확인할 수 있었다. 이러한 기계적 물성 증가는 가교도의 증가 효과보다 나노 크기로 분산된 DA-MMT의 우수한 보강 효과 때문이다. 또한 혼합 방법을 달리한 NR/DA-MMT 나노 복합재료(컴파운딩법) 대비 NR/DA-MMT 나노 복합재료(라텍스법)가 클레이의 박리정도 및 분산도의 차이로 인해 높은 모듈러스, 인장강도 및 인열강도를 나타냄을 확인할 수 있었다

• 한국포장학회지
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• 제15권3호
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• pp.99-104
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• 2009

Soy protein isolate (SPI)-based nanocomposite films with three different types of nanoclays, such as Cloisite $Na^+$, Cloisite 20A, and Cloisite 30B, were prepared using a solution casting method, and their optical, tensile, and water vapor barrier properties were determined to investigate the effect of nano-clay type on film properties. Among the tested nanoclays, Cloisite $Na^+$, a hydrophilic montmorillonite (MMT), exhibited the highest transparency with least opaqueness, the highest tensile strength, and the highest water vapor barrier properties, indicating Cloisite $Na^+$ is the most compatible with SPI polymer matrix to form nanocomposite films. The film properties of SPI/Cloisite $Na^+$ nanocomposite films were strongly dependent on the concentration of the clay. Film properties such as optical, tensile, and water vapor barrier properties improved significantly (p<0.05) as the concentration of clay increased. However, the effectiveness of addition of the clay reduced above a certain level (i.e., 5wt%), indicating that there is an optimum amount of clay addition to exploit the full advantage of nanocmposite films.

• 한국포장학회:학술대회논문집
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• 한국포장학회 2006년도 정기총회 및 추계학술발표대회
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• pp.54-73
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• 2006

Four different types of chitosan-based nanocomposite films were prepared using a solvent casting method by incorporating with four types of nanoparticles, i.e., an unmodified montmorillonite (Na-MMT), an organically modified montmorillonite (Cloisite 30B), a Nano-silver, and a Ag-zeolite (Ag-Ion). X-ray diffraction patterns of the nanocomposite films indicated that a certain degree of intercalation was formed in the nanocomposite films, with the highest intercalation in the Na-MMT-incorporated films followed by films with Cloisite 30B and Ag-Ion. SEM micrographs showed that in all the nanocomposite films, except the Nanosilver-incorporated one, nanoparticles were dispersed homogeneously throughout the chitosan polymer matrix. Consequently, mechanical and barrier properties of chitosan films were affected through intercalation of nanoparticles, i.e., tensile strength (TS) increased by 7-16%, while water vapor permeability (WVP) decreased by 25-30% depending on the nanoparticle material tested. In addition, chitosan-based nanocomposite films, especially silver-containing ones, showed a promising range of antimicrobial activity.

• 한국안전학회지
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• 제21권1호
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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.

• International Journal of Precision Engineering and Manufacturing
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• 제9권4호
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• pp.63-65
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• 2008

The increased interest in reducing the environmental effects caused by releasing organic compounds and aqueous waste has motivated the development of polymeric materials in supercritical fluids. Recently, supercritical fluids have been used in material synthesis and processing because of their special properties, such as high diffusivity, low viscosity, and low surface tension. Supercritical carbon dioxide is the most attractive because it is non-toxic, non-flammable, and has moderate critical temperature and critical pressure values. Supercritical carbon dioxide can also swell most polymers. In this study, we prepared polymer/clay nanocomposites using supercritical fluids. Cloisites 10A, 15A, 25A, and 30B used in this study are montmorillonites modified with a quaternary ammonium salt. The nanocomposites of polymer/clay were characterized by X-ray diffraction, thermogravimetric analysis, and differential scanning calorimetry.