• Polymer(Korea)
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• v.30 no.1
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• pp.75-79
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• 2006

Silica nanoparticles for polymeric dental restorative composites were prepared by Stober method, and then the effects of surface treatment of silica particles with Lmethacrylofpropyltrimethofsilane $(\gamma-MPS)$ on the dispersity of the silica particles in the organic matrix was investigated. Particles having various average size were prepared by using controlled amounts of tetraethylorthosilicate(TEOS), water, and catalyst and by changing solvent used for reaction. The site of particles prepared by using methanol as solvent was smaller than that prepared by using ethanol as solvent. In addition, the size of particles was increased by decreasing amounts of water and by increasing amounts of TEOS and catalyst. Hydrophobic silica nanoparticles was prepared by reacting hydrophilic nanoparticles with $\gamma-MPS$ to improve interfacial properties with organic matrix. Amounts of $\gamma-MPS$ per unit mass of the particles was increased by decreasing particle size. even though the amount of $\gamma-MPS$ per specific surface area were nearly the same regardless of the particle size. The dispersity of the silica particles in the organic matrix was improved when the surface treated silica particles were used for preparing the polymeric dental restorative composites.

• Polymer(Korea)
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• v.33 no.4
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• pp.347-352
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• 2009

Charged organic-inorganic composite particles were prepared for the application to electrophoretic display technology such as electronic paper. $TiO_2$ and $Co_3O_4$ particles were used for core particles and were coated with poly(methyl methacrylate) by dispersion polymerization. Composite particles were endowed with charge moiety for electrophoresis; positive charge for $TiO_2$ and negative charge for $Co_3O_4$ composite particles. Scanning electron microscopic results revealed that the charged composite particles have spherical shape. Densities of the composite particles were controlled to be that of medium of electrophoresis. Density of $TiO_2$ particle changed from 4.02 to 1.44 g/$cm^3$ after the polymer coating, and that of $Co_3O_4$ particles changed from 6.11 to 1.49 g/$cm^3$. Urea, melamine, and formaldehyde were used as wall materials for capsule, and microcapsule containing black or white particles inside were prepared by in-situ polymerization. Microcapsule showed the inspection by a video microscope demonstrated the formation of uniform transparent capsules.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.14 no.3
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• pp.83-89
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• 2004

In this work, HA/$TiO_2$ biocomposite to get high mechanical properties with biocompatibility were prepared. HA/$TiO_2$ biocomposite powders were prepared by mixing $TiO_2$ and HA powders which were synthesized through sol-gel, precipitation and hydrothermal methods. The mixing ratio was fixed at 1:1 ratio (HA/$TiO_2$, wt%). HA/$TiO_2$ biocomposite powders showed different microstructures depending on their particle size and shape. The smaller particles were coated on the surface of larger particles, whereas they were well mixed and dispersed when both $TiO_2$ and HA were nanocrystallites. HA/$TiO_2$ biocomposite powders with homogeneous microstructure showed high sintered density and good mechanical properties.

• Applied Chemistry for Engineering
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• v.7 no.6
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• pp.1061-1068
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• 1996

The conducting polymer composites were prepared by imbibing the porous particle wish the $FeCl_3$ oxidant solution, drying the imbibed porous particle, and imbibing again with pyrrole solution for polymerization to take place in the pore of porous particles. The effect of synthesis conditions on the conductivity of composite polymers were investigated. It was found that the conductivity of composite polymers was dependant on the concentration of pyrrole monomer, nature of the oxidants and solvents used for the oxidant and pyrrole, which influence the degree of penetration/distribution of polyprrole in the composite and reaction of dopant with pyrrole.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2011.03a
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• pp.56-56
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• 2011

알코올 환원법(alcohol reducing process)은 화학적 환원제가 필요하지 않은 화학합성법으로 메탄올, 에탄올, 프로판올, 이소프로판올, 부탄올 등 C1-C4의 알코올류, 에틸렌 글라이콜, 디에틸렌 글라이콜, 프로필렌 글라이콜과 같은 글리콜류 등이 용매이자 환원제로써 사용된다. 전형적으로 금속 전구체를 상기의 알코올류나 글리콜류에 용해 또는 분산시킨 후 그 용액을 환류 조건하에서 가열하게 되면 금속 이온과 용매간의 산화, 환원반응에 의하여 금속이온이 금속원자로 환원되며, 환원된 금속 입자들은 핵 행성과 성장 과정을 거쳐서 입자를 형성하게 된다. 본 연구에서는 알코올환원법을 이용하여 나노크기의 은입자제조를 시도하였고, 이를 PET 칩과의 마스터배치 제조을 시도하였으며, 이의 항균성능을 연구 고찰하였다. 30 ~ 80 nm의 은파우더를 제조할 수 있었으며, 우수한 항균성능을 갖는 Ag/PET 마스터배치를 제조할 수 있었다. 이를 활용하여 나노은입자기반의 항균섬유을 제조하여 이를 활용한 기모경편성물 제조의 기초데이타로 활용이 가능하리라고 사료된다.

• Proceedings of the Optical Society of Korea Conference
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• 2006.07a
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• pp.457-458
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• 2006

졸겔공정을 이용하여 Ag나노입자가 형성된 석영유리계 유리박막을 제조하였다. Dip-coating 과 건조 및 소결처리를 거쳐 $60{\sim}275nm$ 두께의 박막을 제조하였고, TEM 분석 결과 $2{\sim}5nm$ 크기의 Ag나노 입자가 유리박막에 형성된 것을 확인하였다.

• Applied Chemistry for Engineering
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• v.21 no.6
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• pp.676-679
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• 2010

Nano composite particles were synthesized from a bulk ZrVFe alloy ingot by transferred DC thermal plasma. Effects of plasma gas flow rate on the characteristics of the produced nano composite particles were investigated. The characteristics of the synthesized powder were analyzed by field scanning electron microscopy (FE-SEM), light scattering particle size analyzer (PSA), energy dispersive X-ray spectroscopy (EDS), X-ray diffractometer (XRD), and Brunauer-Emmett-Teller (BET) surface area analyzer. As the flow rate of plasma gas increased from 20 L/min to 40 L/min, the average particle size decreased from 91 nm to 55 nm, the particle size distribution became narrower, the surface area increased from $200\;m^2/g$ to $255\;m^2/g$, the particle composition was nearly unaffected, and the particle crystallinity was improved.

• Applied Chemistry for Engineering
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• v.9 no.6
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• pp.846-851
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• 1998

An experimental research on the preparation of zinc oxide fine particles in w/o emulsions was conducted. Precipitation solutions were zinc nitrate aqueous solutions with hexamethylenetetramine(HMTA) as precipitant. The precipitation solutions formed stable w/o emulsions with kerosine in the presence of Span 80. Homogeneous precipitation reaction occurred in the w/o emulsion after the resultant w/o emulsion was heated above the decomposition temperature of HMTA and zinc oxide particles were precipitated. In some case, zinc oxide particles of bi-modal distribution were obtained. However, zinc oxide fine particles of narrow particle size distribution could be obtained, even when the initial zinc concentration of precipitation solution and the conversion to zinc oxide are both higher that those in bulk homogeneous precipitation.

• Proceedings of the Korean Fiber Society Conference
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• 2003.04a
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• pp.21-24
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• 2003

SiO$_2$ 입자는 촉매, 촉매의 담체, 크로마토그래피를 위한 충진제등 여러 산업에 응용되고 있다.$^{1)}$ 본 연구 에서는 기능성을 가지는 입자를 제조하기 위해 SiO$_2$로써 기본적인 입자를 제조하고, 그 속에 소취특성을 가지는 TiO$_2$와 날염을 위한 EVA-microsphere를 포함시켜서 소취제로서, 그리고 날염 분체로서의 기능을 가진 입자들을 제조하고자 하였다. 실리카(silica)는 일반적으로 규소산화물을 지칭하는 명칭으로서, SiO$_2$뿐 아니라 결정구조상 4-6개의 산소원자로 둘러싸인 모든 형태의 규소산화물을 지칭 하는 것이고$^{2)}$ 수용액상의 물유리는 실리카 졸의 값싼 상품으로 산업분야에 널리 알려져 있다. (중략)

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.266-266
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• 2010

실리콘 나노잉크를 이용한 프린팅 공정을 적용하여 결정질 실리콘 박막을 제조하였으며, 다양한 공정조건에 따른 박막의 특성을 연구하였다. 기존의 실리콘 박막형 제조 기술은 고가의 진공프로세스이므로, 비진공 프린팅 공정의 대체를 통하여 박막 태양전지의 제조원가를 획기적으로 절감할 수 있다. 실리콘 나노입자는 저온 플라즈마를 사용하여 합성하였으며, 스핀코팅 (spin coating), 드롭핑 (dropping), 딥핑 (dipping) 등의 프린팅 공정을 이용하여 단결정 실리콘 웨이퍼 위에 박막을 형성하였다. 사용된 실리콘 나노입자는 10 ~ 50 nm 의 크기와 단결정 구조를 갖는다. 이러한 실리콘 나노입자는 Propylene Glycol 용매에 분산시켜 하부기판에 프린팅 하였다. 이렇게 증착된 나노입자들은 $600{\sim}1000^{\circ}C$의 온도와 다양한 분위기에서 열처리되어 고밀도화 되었다. 제조된 실리콘 박막의 물성 분석은 SEM, EDX, 그리고 X-ray 회절 측정을 통하여 수행되었다.