• Journal of the Korean Ceramic Society
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• v.23 no.5
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• pp.41-46
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• 1986

공침법에 의하여 얻어진 고순도 극미립자인 $BaTiO_3$ 분말의 분산거동을 조사하였다 분산매로는 수용매와 비수용매인 methyl ethyl ketone(MEK)과 ethanol (ETOH)을 이용하였다 Suspension 에서의 입자의 분산상태는 pH 변화와 MEK, ETOH의 몰 비를 조절하여 각각의 suspensions에 polymer(polyvinyl butyral)를 첨가시켜 변화하였으며 그 거동은 유동학적 성질 침강 거동 electrokinetic 성질을 측정함으로써 파악되었다 비 수용매의 몰 비가 3:1 MEK/ETOH-$BaTiO_3$에서 polymer를 0.5~1% 첨가시켰을 때 입자의 분산이 가장 잘 이루어졌다.

• Journal of the Korean Ceramic Society
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• v.38 no.6
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• pp.537-544
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• 2001

뮬라이트, 지르코니아, 뮬라이트/지르코니아 비수성 현탁액의 분산 및 레올로지에 미치는 공정보조제의 영향이 침전밀도, 점도, 입자크기를 측정함으로써 검토되었다. 현탁액의 분산안정성 (높은 침전밀도와 낮은 점도로 특징 된)은 분산제+가소제+결합제를 함유하는 경우에 비하여 분산제 또는 분산제+가소제를 함유하는 경우가 우수하였다. Ball mulling 후의 입자크기분포는 공정보조제의 종류에 거의 영향을 받지 않았다. 결합제를 부가적으로 함유하는 현탁액은 상대적으로 강한 shear thinning 거동을 나타내었다.

• Korean Journal of Materials Research
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• v.22 no.8
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• pp.433-438
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• 2012

A chemical process involves polymerization within microspheres, whereas a physical process involves the dispersion of polymer in a nonsolvent. Nano-sized monodisperse microspheres are usually prepared by chemical processes such as water-based emulsions, seed suspension polymerization, nonaqueous dispersion polymerization, and precipitation polymerizations. Polymerization was performed in a four-necked, separate-type flask equipped with a stirrer, a condenser, a nitrogen inlet, and a rubber stopper for adding the initiator with a syringe. Nitrogen was bubbled through the mixture of reagents for 1 hr. before elevating the temperature. Functional silane (3-mercaptopropyl)trimethoxysilane (MPTMS) was used for the modification of silica nanoparticles and the self-assembled monolayers obtained were characterized by X-ray photoelectron spectroscopy (XPS), laser scattering system (LSS), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), elemental analysis (EA), and thermogravimetric analysis (TGA). In addition, polymer microspheres were polymerized by radical polymerization of ${\gamma}$-mercaptopropyl modified silica nanoparticles (MPSN) and acrylamide monomer via precipitation polymerization; then, their characteristics were investigated. From the elemental analysis results, it can be concluded that the conversion rate of acrylamide monomer was 93% and that polyacrylamide grafted to MPSN nanospheres via the radical precipitation polymerization with AAm in ethanol solvent. The microspheres were successfully polymerized by the 'graft from' method.