• Membrane Journal
• /
• v.19 no.1
• /
• pp.47-53
• /
• 2009

The aim of this paper is to prepare metal/ceramic composite ultrafiltration membranes by coating inorganic particles on a metallic hollow fiber filter. The diameter and the pore size of the filter was 2.0 mm and $2{\sim}8{\mu}m$. The metal/ceramic composite ultrafiltration membranes were obtained by a coating process of silica and titania sols on top of the metallic filter. For this purpose the method of fast freeze drying and dip-coating were used. It was found that the pore size of the membrane was about 50 nm from SEM and PMI characterization. The pore size was controlled by changing the size of the particles, sintering period and temperature.

• Applied Chemistry for Engineering
• /
• v.24 no.4
• /
• pp.357-362
• /
• 2013

Monodispersed polystyrene latex spheres (PLS) and PS-MPS/silica composite nanospheres were used to test high efficiency particulate air (HEPA) filters. Prior to filter tests, all nanospheres used in this work were characterized by measuring their average particle diameters and coefficients of variation (CV) for assessing them as artificial dusts. The average particle sizes of PLS and composite nanospheres could be well controlled in the range of 100~300 nm well by changing reaction temperature and the amount of a stabilizer during emulsion polymerization. The CV of all nanospheres were also in the range of 3~7%, lower than 15% that is the criterion for monodispersed particle distributions. Furthermore the results of HEPA filter tests show that all nanospheres used were quite proper as artificial dusts for testing air filters.

• Elastomers and Composites
• /
• v.43 no.3
• /
• pp.157-165
• /
• 2008

Suspension polymerization was carried out to synthesize poly(butyl methacrylate) (PBMA) composite particles containing carbon black. Water was selected as a reaction medium, hydrophobic silica as a stabilizer and azobisisobutyronitrile as an initiator. Concentration of stabilizer was varied from 0.67 to 2.55 weight% with respect to the water, and that of initiator was varied from 0.25 to 3.00 weight% with respect to the butyl methacrylate (BMA) monomer. All polymerization reactions were conducted at 75$^{\circ}C$. It is found that stabilizer concentration has no impact on reaction kinetics, while an increase in initiator concentration enhances polymerization reaction rate. Increase of carbon black concentration from 1 to 3 to 5 wt% into PBMA displayed progressive decrease in reaction conversion. The particle diameter of PBMA composite particles containing carbon black was found to be between 5 and 30 ${\mu}m$. Glass transition was determined to range from 23.8 to 24.7$^{\circ}C$, irrespective of variation in the concentration of stabilizer, initiator or carbon black.

• Membrane Journal
• /
• v.27 no.2
• /
• pp.182-188
• /
• 2017

Sulfonated poly(arylene ether sulfone) (SPAES)-3-mercaptopropyl silica gel (3MPTSG) composite membranes with improved oxidative stability were prepared for polymer electrolyte fuel cell application. It has been reported that ether part of main chain of aromatic hydrocarbon based membranes were weak to radical attack to decrease membrane durability. In this study, the hydrophilic inorganic particles were introduced by minimizing a decrease in ion conductivity and increasing an oxidative stability. The composite membranes were investigated in terms of ionic conductivity, ion exchange capacity (IEC), FT-IR, TGA and contact angle, etc. As a result, increasing amount of the 3MPTSG resulted in decrease in proton conductivities and water uptakes at 100% R.H. but enhanced thermal and oxidative stabilities.

• Korean Journal of Materials Research
• /
• v.19 no.12
• /
• pp.649-656
• /
• 2009

Inorganic oxide colloids dispersed in alcohol were applied to a stainless steel substrate to produce oxide coatings for the purpose of minimizing emissive thermal transfer. The microstructure, roughness, infrared emissive energy, and surface heat loss of the coated substrate were observed with a variation of the nano oxide sol and coating method. It was found that the indium tin oxide, antimony tin oxide, magnesium oxide, silica, titania sol coatings may reduce surface heat loss of the stainless steel at 300${\circ}C$. It was possible to suppress thermal oxidation of the substrate with the oxide sol coatings during an accelerated thermal durability test at 600${\circ}C$. The silica sol coating was most effective to suppress thermal oxidation at 600${\circ}C$, so that it is useful to prevent the increase of radiative surface heat loss as a heating element. Therefore, the inorganic oxide sol coatings may be applied to improve energy efficiency of the substrate as the heating element.

• 한국가스학회:학술대회논문집
• /
• 2003.10a
• /
• pp.114-119
• /
• 2003

• Proceedings of the Membrane Society of Korea Conference
• /
• 2004.11a
• /
• pp.46-49
• /
• 2004

• Proceedings of the Korean Ceranic Society Conference
• /
• 2000.10a
• /
• pp.186.2-186
• /
• 2000

• Proceedings of the Materials Research Society of Korea Conference
• /
• 2005.05a
• /
• pp.135-135
• /
• 2005

• Macromolecular Research
• /
• v.17 no.9
• /
• pp.718-720
• /
• 2009