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우종표 ( U Jong Pyo ),조선영 ( Jo Seon Yeong ) 한국유화학회 2003 한국응용과학기술학회지 Vol.20 No.4
N/A Aqueous polyurethane dispersion was synthesized using phosphorus compound which received significant attention for the replacement of halogenated flame retardants. In this study, polyols which have phosphorus moity in their structural unit were synthesized by two-step polycondensation reaction using dimethyl phenylphosphonate, ethylene glycols, adipic acid, and 1,4-butanediol. In the next step, polyurethane dispersion was prepared using these polyols, isophorone diisocyanate with dimethyl propionic acid. The particle size of polyurethane latex was reduced from 347㎚ to 240㎚ with increasing DMPA content. It was observed that the LOI values of prepared coatings increased from 27% to 35% with increasing phosphorus content.
PMMA 입자특성과 광확산필름의 광특성과의 상관관계에 관한 실험적 연구
우종표 ( U Jong Pyo ),홍진호 ( Hong Jin Ho ),안치희 ( An Chi Hui ),김윤재 ( Kim Yun Jae ) 한국유화학회 2003 한국응용과학기술학회지 Vol.20 No.4
N/A Crosslinked poly(methyl methacrylate) particles from 2.4 to 8.1㎛ in diameter were prepared by homogenized suspension polymerization. The effect of polymerization parameters such as homogenizing speed, homogenizing time and stabilizer concentration on the particle size were examined. Optical diffusion films were prepared with the crosslinked poly(methyl methacrylate) particles. The effect of film thickness, particle size, and particle distribution on transmittance and haze of optical diffusion film was examined. Transmittance of optical diffusion film increased with increasing particle size and decreasing film thickness. Haze increased with increasing film thickness and decreasing particle size. We also found the existence of an optimum ratio for optical performance when the mixture of small particle and large particle was used.
유화중합을 이용한 PMMA/Clay 나노컴포지트의 제조
김철우 ( Kim Cheol U ),우종표 ( U Jong Pyo ) 한국유화학회 2003 한국응용과학기술학회지 Vol.20 No.3
N/A Poly(methyl methacrylate)/clay nanocomposite particles with particle size of 275~292 nm range were successfully prepared using emulsion polymerization. The content of montmorillonite based on the methyl methacrylate monomer was chosen as 30 wt.%. 2,2-azobis(isobuthylamidine hydrochloride) and n-dodecyltrimethylammonium chloride were used as an initiator and a surfactant in anionic emulsion system. The evidence of intercalated /exfoliated structure of montmorillonite in the nanocomposite prepared in our experiment was confirmed by wide angle x-ray diffraction patterns of d_(001) plane. Thermal behavior of nanocomposite was traced using DSC and TGA. It was found that the nanocomposite particle prepared by cationic emulsion system showed intercalated structured. We also found that the nanocomposite particle obtained from anionic emulsion system resulted in the fully exfoliated structure.
KOH 활성화에 의한 피치계 고품질 활성탄의 제조 및 특성
이은지,권순형,최푸름,우종표,정지철,김명수,Lee, Eun-Ji,Kwon, Soon-Hyung,Choi, Poo-Reum,U, Jong-Pyo,Jung, Ji-Chul,Kim, Myung-Soo 한국응용과학기술학회 2014 한국응용과학기술학회지 Vol.31 No.3
In order to prepare high-quality activated carbons (ACs), coal tar pitch (CTP), and mixtures of CTP and petroleum pitch (PP) were activated with KOH. The ACs prepared by activation of CTP in the range of $700{\sim}1000^{\circ}C$ for 1~5 h had very porous textures with large specific surface areas of $2470{\sim}3081m^2/g$. The optimal activation conditions of CTP were determined as CTP/KOH ratio of 1:4, activation temperature of $900^{\circ}C$, and activation time of 3 h. The obtained AC showed the highest micro-pore volume, and pretty high specific surface area and meso-pore volume. The micro-pore volumes and specific areas of activated mixtures of CTP and PP were similar to each other but the meso-pore volume could be increased. In order to change the degree of crystallinity of precursors before KOH activation process, the CTPs were carbonized in the range of $500{\sim}900^{\circ}C$. As the carbonization temperature increased, the specific surface area and pore volume of the activated ACs with the same activation conditions for CTP decreased dramatically. It was demonstrated that the increased pore size distribution of AC electrodes in the range of 1 to 2 nm plays an important role in the performance of electric double-layer capacitor.
라텍스 입자구조가 필름형성 및 필름물성에 미치는 영향 (1) -모델 복합 라텍스 입자의 제조 및 특성-
주인호 ( Ju In Ho ),안재원 ( An Jae Won ),변자훈 ( Byeon Ja Hun ),우종표 ( U Jong Pyo ) 한국유화학회 2004 한국응용과학기술학회지 Vol.21 No.1
N/A In this study, various model composite latexes were synthesized using n-butyl acrylate and methyl methacrylate as comonomers by seeded multi-staged emulsion polymerization. Monodispersed model composite latex particles with size of 190 nm and polydispersity index of 1.05, which have various morphology including random copolymer particle, soft-core/hard-shell particle, hard-core/soft shell particle, and gradient-type copolymer particle, homopolymers particles were prepares. The designed morphology of model composite particles were confirmed.