• Journal of the Korean Ceramic Society
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• v.49 no.5
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• pp.423-426
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• 2012

$Al_2O_3$/NiO powder was obtained through hydrolysis-condensation reactions and thermal treatments. An organic additive, triblock copolymer surfactant P123, was added to the starting materials to control the surface area and morphology. The synthesized powder was characterized by X-ray diffractometry (XRD), field-emission scanning electron microscopy (FE-SEM) and a Brunner-Emmett-Teller surface analysis (BET). The heterogeneous catalytic activity of this powder was applied to an epoxidation reaction of styrene and was monitored using a gas chromatograph with mass spectrophotometry (GC/MS).

• Bulletin of the Korean Chemical Society
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• v.27 no.10
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• pp.1562-1566
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• 2006

Mesoporous silica films with three different pore sizes were prepared by using cationic surfactant, non-ionic surfactant, or triblock copolymer as structure directing agents with tetramethylorthosilicate as silica source in order to control the pore size and wall thickness. They were synthesized by an evaporation-induced self-assembly process and spin-coated on Si wafer. Mesoporous silica films with three different pore sizes of 2.9, 4.6, and 6.6 nm and wall thickness ranging from $\sim$1 to $\sim$3 nm were prepared by using three different surfactants. These materials were optically transparent mesoporous silica films and crack free when thickness was less than 1 m m. The photoluminescence spectra found in the visible range were peaked at higher energy for smaller pore and thinner wall sized materials, consistent with the quantum confinement effect within the nano-sized walls of the silica pores.

• Proceedings of the SCSK Conference
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• 2003.09a
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• pp.232-257
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• 2003

It has been shown that transparent microemulsion gels of flexibly adjustable viscosity containing less than 10％ w/w surfactants can be obtained just by cooling down through a new 1-step preparation procedure (via 4 different in-situ colloidal systems) using PIT-technology with a range of emulsifiers, co-emulsifiers and lipids. They can be used for a wide scope of applications. Specific examples have been given with antiperspirant formulas that proof the stability of these thickened microemulsions even with high content of electrolytes and low pH. We propose that the structure of these microemulsion gels can be described by cross-linking of nano-fine oil droplets via an ABA-triblock copolymer. A new generation of transparent antiperspirant roll-ons with significantly improved skin tolerance can now be formulated as an attractive alternative to alcohol-based products.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.180-180
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• 2006

A novel preparation method for core/shell nanoparticles with protein drug-loaded lipid core was designed and characterized. The lipid core is composed of lecithin and protein drug and the polymeric shell is composed of Pluronics (poly (ethylene oxide)-poly (propylene oxide)-poly(ethylene oxide) triblock copolymer, F-127 For the application of core/shell nanoparticles as a protein drug carrier, lysozyme and Vascular Endothelial Growth Factor (VEGF) were loaded into the core/shell nanoparticles by electrostatic interaction and the drug release pattern was observed by manipulating the polymeric shell.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.199-199
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• 2006

Microwave-irradiation has become a common heat source in organic chemistry in the last decade. In recent years, polymer chemists also discovered the advances of microwave heating that include fast and efficient heating as well as the homogeneous heat profile and the easy access to pressurized reaction conditions. In this contribution, we report our investigations on the cationic ring-opening polymerization of 2-oxazolines that lead to a tremendous acceleration from several days to several minutes polymerization time. In addition, the optimized microwave-assisted polymerization procedure was applied for the preparation of libraries of diblock and triblock copolymers that were used for the determination of structure-property relationships in poly(2-oxazoline)s.

• Proceedings of the Polymer Society of Korea Conference
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• 2006.10a
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• pp.380-380
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• 2006

Styrene-Butadiene diblock or styrene-butadiene-styrene triblock copolymers are industrially important materials for asphalt modification and adhesives. A kinetic modeling study on non-isothermal anionic styrene-butadiene diblock copolymerization system is presented. The model deals with the association/dissociation reaction of initiator and propagating ion pairs in its kinetic scheme. By comparing model calculation results with real plant data, it is possible to obtain useful ideas for more efficient plant operation. For example, the model clearly provides important relation between the reaction temperature profile and the conversion of monomers.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2003.10a
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• pp.111-114
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• 2003

Thermosets are highly cross-linked polymers with a three-dimensional molecular structure. The network structure gives rise to mechanical properties, however, one major drawback of thermosets, which also results from their network structure, is their poor resistance to impact and to crack initiation. In this study, to solve this problem, the reactive thermoplastics such as amine terminated polyetherimide (ATPEI), ATPEI-CTBN-ATPEI(ABA) triblock copolymer, CTBN-ATPEI(AB) diblock copolymer, and carboxyl group modified ATPEI was synthesized, after that blended with epoxy resin, and the carbon fiber reinforced composites were fabricated. The impact load, energy, and delamination were investigated by using drop weight impact test and C-scan test. As a results, the ABA/epoxy blend system showed good impact properties.

• Proceedings of the Korean Society For Composite Materials Conference
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• 1999.11a
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• pp.172-176
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• 1999

에폭시 수지의 강인성 향상을 위하여 양말단에 아민 반응기를 가지는 PES-CTBN-PES triblock copolymer를 합성하여 이를 에폭시 수지의 강인화제로 사용하였으며 경화제로는 p-DDS(p-dichlorodiphenylsulfone)를 사용하였다. 또한 공중합체에 의한 물성 향상효과를 CTBN과 PES-NH$_2$의 블렌드에 의한 경우와 비교하였다. 강인화된 에폭시 수지의 물성은 강인성 및 굴곡특성을 측정하여 분석하였으며, 열특성은 DSC, TGA, 및 DMA에 의해 실시되었다. 그리고 강인화된 에폭시 수지의 강인성 향상 mechanism을 규명하기 위하여 파단면을 SEM으로 분석하여 상분리 거동을 고찰하였다. 높은 유리전이온도와 우수한 기계적 물성을 가지는 고성능 기능성 폴리설폰(PES-NH$_2$)과 상용 액상 고무 첨가제인 CTBN을 이용하여 합성된 공중합체를 강인화제로 사용함으로써 열안정성, 탄성률 및 내식성의 감소없이 에폭시 수지의 쳐대 단점인 강인성을 최적 수준으로 개선시킬 수 있었으며 공중합체의 에폭시 수지에 대한 우수한 용해도에 따른 가공성이 향상되었다.

• Proceedings of the Korea Crystallographic Association Conference
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• 2002.11a
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• pp.49-49
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• 2002

A strategy for the synthesis of more stable and large periodic mesoporous organo-silica materials has been developed for the 2D hexagonal mesoporous organosilica by the core-shell approach using nonionic PEO-PLGA-PEO triblock copolymer templates. The BET surface area of the solvent-extracted hexagonal mesoporous organosilica is estimated to be 1,016 ㎡/g and the pore volume, pore diameter, and wall thickness are 1.447 ㎤/g, 65 Å, and 43 Å, respectively. More hydrophobic PLGA block than the PPO block used for templates of mesoporous silica proves to be quite effective in confining the organosilicates within the PEO phase. Reaction temperature and acid concentration of an initial solution as well as the chemical nature of the bloc k copolymer templates also demonstrate to be important experimental parameters for ordered organosilica mesophase. Moreover, the mesoporous organosilicas prepared with the PEO-PLGA-PEO block templates maintain their structural integrity for up to 25 days in boiling water at 100℃. The mesoporous materials with large pores and high hydrothermal stability prepared in this study has a potential for many applications.

• Proceedings of the KOSOMBE Conference
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• v.1996 no.11
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• pp.327-330
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• 1996

Poly(L-leucine)(PLL)/poly(ethylene oxide)(PEO)/poly (L-leucine)(PLL) block copolymers were synthsized by polymerization of L-leucine N-carboxyanhydride with diamine-terminated PEO for possibility of wound dressing which may have several advantages such as 1) increase of solubility, 2) control of biodegradation, 3) absorption of body fluid. 4) non-immunogenic effect than PLL homopolymer wound dressing aleady commercialized. Water content increased with an increase of PEO content in the block copolymer due to the hydrophilicity of PEO. Release of silver sulfadiazine(AgSD) from AgSD loaded wound dressing increased with an increase of PEO content in the block copolymer. It was found that the number of Pseudomonas aeruginosa decrease with an increase of PEO content due to the fast release of antibacterial agents with an increase of PEO content in the block copolymer.